Qatar Foundation Annual Research Conference Proceedings Volume 2014 Issue 1
- تاريخ المؤتمر: 18-19 Nov 2014
- الموقع: Qatar National Convention Center (QNCC), Doha, Qatar
- رقم المجلد: 2014
- المنشور: ١٨ نوفمبر ٢٠١٤
101 - 150 of 480 نتائج
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A Framework For Assessing Soil, Climate And Market Constraints To Improve Food Security In Qatar
المؤلفون: Abul Huda, Simeon Kaitibie, Phil Moody, Munshi Haq, Abukari Issaka, Kenzu Abdella, Ahmed Moustafa, Ipek Goktepe, Kep Coughlan, Marco Pollanen and Noel VockImproving agricultural production in Qatar faces a number of challenges mainly related to adverse climatic conditions, quality of soils, scarcity of irrigation water, inappropriate crop rotations, market constraints and ineffective agricultural subsidies. Strategies to overcome these problems may include a) increasing domestic production in Qatar by using a combination of high-tech water-efficient field and greenhouse production systems focussed on high quality end-products to fill gaps in the supply market, and b) land purchase and contract farming of broad-acre crops in more resource-rich countries such as Australia. Qatar produces only about 8-10 percent of food consumed, yet domestic production is significantly constrained by lack of market access. In this paper, a holistic framework is developed for assessing climate, soil and market constraints, and for generating an optimized list of food crops that could be grown under output price uncertainty and severely limiting arable land and water conditions in Qatar. Components of the framework include assessing the yield potential of selected crops through simulation modelling using historical climate and soils data. In a case study using wheat as a selected crop, potential yields were simulated using soils and long-term climate data for five Australian locations. These locations are Dalby in Queensland; Trangie and Junee in New South Wales; Esperance and Jerramungup in Western Australia. An assessment has been made of the site/soil constraints to identify yield limiting factors. In addition, the module will be adapted to identify suitable locations for producing vegetable crops in Qatar. Soil and climate data from five locations in Qatar (Al Sulaiteen Agricultural and Industrial Complex site, Qatar University Farm site, Arab-Qatari Farm site, Outoriya, and Rodhat Al Faras) are being collected for this purpose. The framework will be informed by a large amount of historical data in Qatar, including crop types and yield, land and water use coefficients, food import and export data, food prices, and food preferences. Output obtained from the framework will allow Qatari investment operations in Australia and other countries to determine the best locations for wheat production. At the same time we will generate a prioritized list of profitable vegetables that can be grown in Qatar in order to improve the food security situation. The findings of this paper will contribute towards achieving the goals of our research project "Improving Food Security in Qatar: Assessing Alternative Cropping Systems Feasibility and Productivity in Variable Climates, Soil and Marketing Environments" (NPRP6-064-4-001) funded by Qatar National Research Fund (QNRF) through its National Research Priority Program.
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Zinc Oxide Nanostructures For High Efficiency Solar Cells
المؤلفون: Amir Abdallah and Nouar TaebtThe main two challenges hindering the deployment of solar cells in large scale are the high cost and low efficiency. One of the strategies to reduce the cost is by using thin film materials with enhanced solar cell conversion efficiency. However, thin film materials suffer from weak absorption and the presence of defects, which act as recombination canters for charge carriers. Various studies were conducted to improve absorption in thin film solar cells. However, those approaches are not optimized yet for high efficiency solar cells. In this study, we focus on enhancing light absorption of thin film silicon solar cells by using Zinc Oxide (ZnO) nanostructures.
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Innovative Non-specific Elemental And Molecular Fingerprint Strategy For Produced Water Before Reuse
المؤلفون: Hugues Preudhomme, Claude Sadois, Philippe Julien, Genevieve Lebas and Basem ShomarBackground and Objectives Produced water for future reuse is a key component of Qatar's Water Security Grand Challenge (WSGC) and forward progress within the Grand Challenge is dependent on comprehensive characterization and potential risks. To date, only major compounds of produced waters are characterized. For safety reason, a global fingerprint of both natural and anthropogenic trace organic and inorganic constituents must be created before any treatment or reuse. The main objective of this innovative strategy is to reach an accurate, non-specific monitoring of organic and inorganic ultra-trace compounds by mass spectrometry. Methods Produced water samples were collected in Qatar's oil field from various Qatar's produced wells with a high water cut in order to evaluate the water quality and to select produced waters for further studies for treatment and reuse. To highlight the benefit of this innovative analytical approach, the study was focused on highly hydrophilic compounds which remain in the aqueous phase even after oil separation. Naphtenic acids, Fluorinated acids, BTEX biodegradation byproducts, halo acetic acids, and trace metals (Ni, Cr, Fe, Cd, U etc.) are related to produced water characteristics, oil and gas industry and well tubing. The quantifications were firstly completed by UHPLC-ESIqQqTOF Maxis HD (Bruker) and by ICP-MS Aurora Elite (Bruker). All analyses were performed in QEERI laboratories. The direct analyses of produced water were based on synergic used of ultra high pressure liquid chromatography, non-specific high resolution and inductively coupled plasma mass spectrometry. The development of robust, accurate and high end methods allows us to generate high quality data for immediate chemical information extraction, long term inter sample comparison and long term raw data storage for further studies. The in silico storage of water's nonspecific fingerprint is an interesting and promising alternative to long term storage of diluted media like water samples which are always critical. Results The current study was performed using Qatar's produced waters and on Congo and Angola's produced waters as reference waters. Despite the sub-ppb level quantification limit, the results of Qatar's produced waters analyzed do not show significant trace of halogenated acetic acids, perfluorinated compounds or BTEX biodegradation byproducts in comparison to the African's produced waters. Trace elements and radionuclides analysis are currently ongoing. Conclusions Here, we introduce innovative analytical strategies on produced water by synergic used of high resolution and multi-elemental mass spectrometry for accurate fingerprint on organic and inorganic ultra-trace contaminants study of water characteristics. Its part of an ongoing process focused on optimizing and developing analytical approaches suitable for Qatar's produced water quality prior to sustainable reuse. The methodology developed (isotopic dilution, standard addition…), is the first bimodal study of its kind. It can be used in the future to perform a non-specific screening of ultra-traces acids, metals and radionuclides compounds. The relative analytical results are being used to drive research efforts within the WSGC.
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Advanced Hard Coatings: Towards A Whole New World
BACKGROUND & OBJECTIVES: Improving materials properties is one of the biggest scientific issues of all the times. When it becomes impossible to further manipulate the raw material, one feasible way to push its properties beyond the theoretical limits is to modify the properties of the surface. That is where advanced surface coatings come in. From a manufacturing point of view, tools for machining are of particular interest. These tools are usually made of hard steels and cemented carbide (WC-Co). For specialized applications, such as aluminium machining, diamond or polycrystalline cubic boron nitride are also used. The main problem with steel, is that it exhibits a relatively low hardness (below 10 GPa) which strongly decreases upon annealing above about 600 K. Thus, the majority of modern tools are nowadays coated with hard coatings, in order to: (i) increase the hardness, (ii) decrease the coefficient of friction, and (iii) protect the tools against oxidation. A similar approach has been recently used to obtain a longer duration of the dies for aluminium die-casting. Multi-component and nanostructured materials represent a promising class of protective hard coatings due to their enhanced mechanical and thermal oxidation properties. METHODS: Three different thin hard nitrogen-rich coatings were mechanically, microstructurally, and thermally characterized: (i) a 2.5 micron-thick nano-layered CrN-NbN, (ii) a 11.7 micron-thick monolayer TiAlN, and (iii) a 2.92 micron-thick multilayer AlTiCrxNy. The main feature of the CrN-NbN coating is the fabrication by the alternate deposition of 4 nm thick-nanolayer of NewChrome (new type of CrN, with strong adhesion and low coating temperature). All the three coatings can reach values of hardness and elastic modulus exceeding 20 and 250 GPa, respectively. Their main applications include stainless steel drawing, plastic materials forming and extrusion, and aluminum alloys die-casting. The here studied TiAlN (SBN, super booster nitride) is one of the latest evolution of TiAlN coatings for cutting applications, where maximum resistance to wear and oxidation are required. The AlTiCrxNy combines the very high wear resistance of the Cr-coatings with peculiarities of the Al-containing coatings, such as high thermal stability and high-temperature hardness. All the coatings were deposited on a S600 tool steel. The coatings were subjected to two different thermal cycling tests: (i) 100 thermal cycles consisting of 60 s dwelling time, respectively at the high- (573 to 1173 K) and at the room-temperature, and (ii) 100 thermal cycles consisting of 115 s dwelling time, at same temperatures of the first test, followed by 5 s dwelling at room-temperature. The temperature induced hardness and elastic modulus coating variations were measured by nanoindentation. RESULTS: During thermal cycling, the TiAlN monolayer coating and the AlTiCrxNy multilayer coating showed a high oxidation resistance even at high temperature, while the CrN-NbN nano-layer coating undergoes a oxidation phenomena, for temperatures above 873 K. CONCLUSIONS: The investigated coatings showed a sufficient-to-optimal thermal response either in terms of mechanical stability, such hardness and elastic modulus, and in terms of oxidation degradation.
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Test Sample Development And Test Procedures For Establishing A Chloride Stress Corrosion Cracking Corrosion Atlas For Qatar
المؤلفون: Hanan Farhat, Roy Johnsen and Demian RoulstonTest Sample Development and Test Procedures for Establishing a Chloride Stress Corrosion Cracking Corrosion Atlas for Qatar H. Farhat*, R. Johnsen** & D. Roulston** Abstract Oil and gas production, and petrochemical plants in offshore and onshore locations in Qatar are exposed to severe environmental conditions. The combination of high humidity, high concentration of chloride ions, high temperature and the presence of residual tensile stresses due to welding or other forming process make these facilities susceptible to chloride-induced stress corrosion cracking (CSCC). High temperature causes seawater to evaporate, condensate, and dry on metal surfaces, thereby enhancing local build-up of aggressive species, such as chloride on the metals' surfaces. If the surface of the metal is insulated, the condensate may be trapped under the insulation leading to high localized corrosion damage. This is complicated by sand storms which leave sand particles with aggressive species such as chloride and sulfide on the surfaces exposed to this environment. A corrosion atlas for chloride stress corrosion cracking was developed in Qatar. Seven different stainless, duplex and high nickel alloy steels were investigated. One hundred samples of each material were exposed to a stress equivalent to 80% and 100% of their yield strength. They were then, distributed in different onshore and offshore sites for Qatar Petroleum, and were inspected periodically for CSCC. The temperature, humidity and time to failure were recorded. This paper describes the samples, and sample rack design, testing procedure, as well as the stress application method applied to the samples. *College of the North Atlantic-Qatar ** Qatar Petroleum Research and Technology Department
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Highly Efficient Electrocatalysts For Recycling Co2
المؤلفون: Shahid Rasul and Kazuhiro TakanabeThe development of artificial photosynthesis is one of the greatest scientific challenges of our times, not only to protect the environment but also to ensure global economic security. To mimic the natural photosynthesis process, a complete understanding of the natural photosynthesis process at the molecular level is essential to enable the production of inexpensive, lightweight, and high-energy-density fuels. Artificial photosynthesis may involve photo/electrocatalytic H2 generation by water splitting or the use of H2 in combination with atmospheric/industrially sourced CO2 conversion products to provide a continuous supply of high-energy carrier fuels at small/medium scales. Recently, Cu2O has received considerable attention in various energy-conversion applications, including photo/electrochemical hydrogen production and the photo/electrochemical conversion of carbon dioxide (CO2) to energy-carrier fuels. The Cu(I) state, with its d10 electronic configuration, is required for cuprous oxides to exhibit photo/electrochemical and chemical catalytic activity. For electrochemical CO2 reduction, Cu(I) sites are proposed to stabilize reaction intermediates such as CO, carbonates (CO23−), formates (HCOO−), and methoxy (H3CO−) adsorbates, as expected from their high heats of adsorption. Although the Cu(I) state makes these materials attractive, the stability of Cu(I) species toward redox reactions remains an issue to be solved. In this study, we report the novel design of multi-metal based electrocatalysts which may introduce different (other than Cu) active species due to effect of the hetro-atoms on the Cu surface. As a result the reaction intermediates on the surface may be stabilized generating CO exclusively as a reaction product of electrochemical reduction of aqueous CO2 while suppressing the competitive H2 generation. The higher selectivity towards CO generation may be attributed to perturbing the d-band metal center or the geometric effects caused by the second metal center around Cu.
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Effect Of Sewage Sludge Application And Method Of Seeding On The Yield Of Barley Using Surface And Sprinkler Irrigation
المؤلفون: Basel Ahmad Alar'raj and Henda MahmoudiArid regions in the world occupy about one quarter of the land surface area. In such regions, satisfactory crop production is impossible without irrigation because of irregular, sporadic and unpredictable rainfall leading to water shortage subsequently supplemental irrigation is a must for reasonable yield. Soil in these regions has poor physical and chemical properties. Since sludge is a source for organic matter and contains many essential nutrients for plant it can be used in these areas to improve soil physical condition and fertility status of such soil. On the other hand a proper irrigation system with proper seeding method will lead to maximum yield. The objectives of current research are to compare the effects of two irrigation systems (sprinkler and surface) on the yield of barley crop in sludge amended arid soil with different sewage sludge rates and to compare the effects of traditional and modern method of seeding. Two experiments were conducted. The first experiment was split plot in randomized complete block design and consisted of two irrigation methods (surface and sprinkler) with four replications. The split plot treatment were two seeding methods the row seeding to a depth of 5 cm and in pre-established furrows of 35 cm depth (5 cm below the bottom of the furrow). Sludge was added at a rate of 30 ton/ha. Results indicated that furrow seeded under diked end surface irrigation treatment produced significantly the highest barley yield because it increases water storage by increasing the infiltration opportunity time. Also the furrows worked as water catchments which reduced run-off. The second experiment was randomized complete block design with four replications. Sludge was added at four different rates (0, 10, 30 and 60 ton/ha). Barley was planted using diked furrow seeding and irrigated by sprinklers. The highest significant barley yield was at 30 ton sludge/ha treatment. The significant increase in barley yield due to sludge is attributed to the increase of soil fertility status by sludge addition as well as to the improvement of soil chemical and physical properties. Using furrow seeding with diked surface irrigation in crusted soils increased barley yield significantly owing to the increase in soil water availability and controlling salinity in the root zone through leaching that affected the yield.
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Roasted-modified Date Pits In Remediation Of Bromide Ions From Desalinated Water: Kinetic Studies
Disinfection of drinking water is one of the extreme public health activities in Qatar. Chlorination, ozonation, ultra-violet, chloramination, and others are the most important treatment processes used and they can cause the formation of toxic by-products. The existence of bromide (Br-), for example, in water sources might cause in formation of brominated toxic by-products. Up-to-date drinking water treatment methodologies are challenged to successfully eliminate Br- before final consumption. Remediation onto activated carbons has a number of restrictions. Date pits are suitable as raw remediating adsorbent for preparing various modified adsorbents, because particular surface functional groups and the micro-pore structures can be attained by active modifications. The overall objective of this study was to develop an economical and environmentally acceptable process to safely eliminate the levels of Br- from desalinated water. Roasted date pits (RODPs) and activated charcoal (AC) (used as a control) were crushed and sieved with four different particles size ranges. The percentage of Br- removal was also studied under different experimental conditions such as pH, sorbent mass and initial concentration. In addition, surface characterization was also investigated. Experimental date analyses were investigated using different isotherm and kinetic sorption models. The modification of the date pits surface enhanced the Br- removal capacity at high initial concentration of bromide (200 ppm) by 27%. Using scanning electron microscope (SEM), the date pits surface images showed a different in pore sizes upon modification. Removal capacity of RODPs reached 39% at pH 4. In this study the heterogeneity of adsorbing mechanisms and the fitting with pseudo second order model and inter particulate diffusion models were concluded, and more than 35% of Br- removal efficiency was achieved within the RODPs at the first hour of contact time. The adsorption Br- onto RODPs was not fitted well with the pseudo-first order model. It was found that the kinetics of Br- adsorption was followed the pseudo-second order. It was also observed fluctuations in the removal efficiency for smaller particle sizes; indicating heterogeneity of adsorption/desorption and potential chemical bindings, this particular behaviour was not observed and investigated elsewhere in the literature (Figure below). The surface of RODPs contains oxygen functional groups such hydroxyl; hence the presence of such functional groups on the surface of date pits considerably influences on the adsorption mechanism of organic and inorganic compounds on the RODP. Economically RODPs are successfully used to remove Br-, comparing to AC. However, both adsorbents have nearly the same removal efficiency after one hour contact time. Apparently, the removal efficiency of both systems was quite significant. This may cover the way for the cheap and widely available date pits to be used as an adsorbent in water purification process.
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Expression Patterns Of Genes Encoding Antioxidative Enzymes In Date Palm(phoenix Dactylifera) In Response To Salinity Stress
Background Salinity is one of the major abiotic stresses threatening crop productivity worldwide. Plants exposed to severe salinity suffer ionic toxicities, osmotic stress and oxidative damage that lead to inhibition of active photosynthesis, reduction of growth and cell death. Plants ability to detoxify reactive oxygen species (ROS, free radicals) and avoid oxidative damage is considered as one of the important mechanisms to cope with salinity. Accumulation of ROS causes oxidation of various cellular components, damage to DNA and proteins, and can lead to oxidative destruction of the cell. Detoxification of ROS in plant cells is controlled by a combination of antioxidants such as ascorbate (AsA) and glutathione (GSH), and antioxidative enzymes such as superoxide dismutase (SOD), ascorbate peroxidase (APX) and catalase (CAT). Antioxidative enzymes involved on the regeneration of AsA and GSH such as monodehydroascorbate reductase (MDAR) and glutathione reductase (GR) are essential to maintain active pools of both antioxidants. Objectives: The aim of this work was to analyze the expression patterns of the date palm genes encoding antioxidative enzymes under various levels of salt stress. Material and methods: Similar plantlets of date palm cultivar (Khalas) were selected for all treatments in MS medium. Plantlets were subjected to various concentrations of NaCl (100mM, 200mM, 300mM and 400 mM) in addition to control. The expression analysis was performed by RT-PCR Results and Conclusions: The expression patterns of the date palm genes encoding antioxidative enzymes under various levels of salt stress was analyzed. Results showed that remarkable induction of PdCAT, PdGR, PdMDAR, PdSOD and PdAPX was observed. Highest induction of PdCAT and PdGR was observed at 100 mM NaCl while PdMDAR maintained its highest expression at up to 400 mM NaCl. Following salt exposure time course, all the genes maintained up-regulated expression levels up to 6 days compared to control conditions. Moreover, a high and steady induction of glutathione S-transferase (PdGST) was observed, the enzyme that plays key roles in the detoxification of xenobiotics compounds and oxidative stress mechanism. These results suggest that antioxidative enzymes involved in either ROS detoxification or antioxidants regeneration may play crucial roles in the tolerance of date palm to salt stress.
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The Sabkhas Of Qatar: An Ideal Place To Study The Origin Of Dolomitic Hydrocarbon Reservoir Rocks
Many hydrocarbon reservoirs - in Qatar and worldwide - are constituted of dolomite. For this reason, the origin of this Ca-Mg carbonate mineral has been extensively studied by generations of geologists, with the goal of exploiting gas and oil from rock reservoirs in the most efficient way. However, despite more than two centuries of research, several fundamental questions regarding the origin of sedimentary dolomite remain without a convincing answer. Recent research conducted in the field of geobiology suggests that dolomite formation may be the result of a microbial process, that is, organic molecules that in natural environments are produced by microorganisms seem to play a key role for dolomite nucleation at low temperatures in many geological settings. However, this innovative hypothesis is far from being unanimously accepted by the scientific community, and many details on the exact mechanism through which microorganisms mediate dolomite formation are still to be fully understood. The aim of this contribution is to summarize the most recent scientific studies that support the microbial model for dolomite formation, providing examples from culture experiments conducted in the laboratory using artificial growth solutions and from modern dolomite forming environments, such as the hypersaline lagoons located in the State of Rio de Janeiro (Brazil), the sabkhas of Abu Dhabi (UAE), and the sabkhas of Dohat Faishakh and Khor Al-Adaid (Qatar). Furthermore, we will elaborate on why we consider the coastal sabkhas of Qatar to be among the most ideal places on Earth where it is possible to study microbe-mineral interactions in evaporitic environments. In fact, thanks to the distinctive geology that characterizes this region, it is possible to obtain samples documenting the progressive transformation of the living microbial mats that mediate dolomite formation and other authigenic minerals into a fully lithified sediment, which is analogous to dolomite formations constituting economically important gas/oil reservoir rocks. This approach will provide key insights to test whether dolomite present in ancient evaporitic sequences can be interpreted as a fully biological product associated with early diagenesis or whether most of the dolomite forms during later stage metamorphic/replacement events that are controlled by purely abiotic processes. Finally, considering not only the scientific importance but also the aesthetic beauty of the Qatari evaporitic environments, we will discuss the idea and the challenges of transforming selected areas of the modern sabkhas into geoparks - protected natural reserves that would be of interest for the local Qatari population, as well as for tourists visiting Qatar.
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Life Cycle Assessment Of Bio Diethyl Carbonate
المؤلفون: Hind Mamlouk, Christian Nissing and Daniel Curulla FerreDue to the continuous increase in Earth's atmosphere of carbon dioxide, under the threat of climate change, green processes based on chemical fixation of CO2 have recently attracted much attention. A systematic and standardized methodology to evaluate environmental impacts of products is life-cycle assessment (LCA). Along the entire life cycle, all material and energy flows are collected. These flows are linked to potential environmental impacts such as global warming and resource depletion, among many others. The approach of LCA allows understanding the different life-cycle stages of our processes and their environmental impacts. Therefore, LCA seems a suitable methodology for evaluating the environmental impacts of CO2. The aim of this TOTAL study is to investigate and to qualify the environmental performance of bio diethyl carbonate (bioDEC) as compared to a fossil fuel in terms of greenhouse gas emissions by means of a Life Cycle Assessment (LCA). The bioDEC synthesis process, from CO2, used as raw material, and bioethanol is studied, where bioethanol is used from three different biomass feedstocks, namely sugar cane, sugar beet and corn. These different biomass feedstocks will give different diethyl carbonate (DEC) synthesis routes. The results were compared to a fossil fuel (gasoline) and ethanol. To facilitate this goal, the study intends to consider the bioDEC molecule as a whole, taking into account the part of its origin from the CO2 raw material. For this purpose, different system boundaries were considered, showing that the CO2 raw material flow can be considered as neutral throughout the system considered, whatever its origin (CO2 raw material input is equal to related CO2 emissions released during combustion of final fuel). In summary, it can be stated in this study that all investigated bioDEC cases are alternatives to fossil gasoline as they emit less GHGs. When comparing bioDEC and ethanol as final fuels, one observes that ethanol has the better environmental performance of both fuels when considering the same feedstock. That means that for improving the environmental performance, from a GHG emissions perspective regarding bioDEC, we have to consider the following points: * Utilization of ethanol as final fuel without further processing to bioDEC, * Production of bioDEC from another ethanol feedstock, * Utilization of bioDEC as a structural molecule (example plastics) and not as a fuel. We report here the description of the bioDEC product and its pathways, the GHG emissions calculation, the life cycle inventory and the results of life cycle impact assessment.
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Peripheral Co2 Flooding To Enhance Gas Recovery In Carbonate Reservoir
المؤلفون: Tarek Ali, Karim Youssef and Michael FraimManagement of production from gas reservoirs can be a challenging process. The challenge gets bigger when the reservoir is characterized by having a small pore size, such as the tight carbonate reservoirs which are prominent in this part of the world. In such conditions, condensate blockage becomes a real threat to productivity. Carbon dioxide can be injected into the reservoir to combat this threat. We built a reservoir model to conduct a simulation study with the goal of finding the most feasible method for overcoming the negative impact of condensate formation. We have attempted to simulate huff-n-puff enhanced gas recovery in the same reservoir model, but this method did not achieve much success in alleviating the damage caused by condensate blockage. As a result, according to the model and data we collected, using huff-n-puff is not efficient since it failed to maintain the average reservoir pressure as well as CO2 did, therefore peripheral CO2 injection have been tested. The minimum requirement again is to achieve gas plateau production, while also maximizing the condensate recovery and minimizing the CO2 breakthrough into the wells. It was decided that seven CO2 injector wells were to be placed at strategic locations (injectors have been planned to be drilled away from the reservoir and producing wells) across the field in order to enhance the sweeping of condensate as well as minimize CO2 breakthrough. In other words, the injectors had to be at a distance where it can achieve all our simulation objectives. We ended up understanding the effect of the CO2 injection on condensate formation. As a result, it could be notice how the saturation of oil is high near the producing end of the core, this kind of saturation can completely nullify the relative permeability of gas, whereas after using CO2 flooding, the saturation is decreased significantly and the amount of condensate throughout the core is also much less.
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Adsorptive Desulfurization Of Thiophene, Benzothiophene And Dibenzothiophene From Model Fuel By Carbons Derived From Waste Rubber Tires
المؤلفون: Tawfik A. Saleh and Ibrahim DanmalikiThe removal of sulfur compounds from petroleum is increasingly important. In addition to its contribution to form particulate pollution, sulfur emission may cause some health problems. Regarding the negative impact of sulfur in industry, small amount of sulfur may poison the catalysts or diminish its efficiency. A commonly used method for the removal of sulfur-bearing species from fuel is hydrodesulphurization. However, due to the regulations required removal of sulfur to very low levels, several alternative technologies have also been reported for sulfur removal from liquids such as catalytic oxidation, biological sulfur removal and membrane separation. Desulfurization by adsorption has been regarded as the most promising approach. In this work, porous activated carbon was derived from waste rubber tires. Then, it was characterized by means field emission scanning electron microscopy, energy-dispersive X-ray, X-ray diffraction and Fourier transform infrared spectroscopies. The carbons then were used as adsorbents for adsorptive desulfurization. Model fuel samples with known amounts of thiophene, benzothiophene and dibenzothiophene compounds were prepared and used to test the efficiency of the derived carbons for adsorptive desulfurization. The amount of compounds adsorbed was found to follow the order of dibenzothiophene > benzothiophene > thiophene. Adsorption process was found to well fit pseudo second-order kinetic model. The adsorption mechanism was studied by intraparticle diffusion model. The experimental data were fitted to Langmuir, Freundlich and Temkin isotherm models. Adsorption capacity is governed by chemical interaction and pore volume of the adsorbents. The results revealed that Freundlich isotherm provided a better fit to the experimental data. The developed sorbent exhibited the advantages of being inexpensive and of double benefit to the environment.
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Trends In Aerosol Optical Thickness Over The Middle East: Impacts On Solar Power Generation
المؤلفون: Mohammed AyoubQatar and the region are experiencing transformative growth over relatively very short periods of time, due primarily to hydrocarbon based energy resources. As the country pushes to meet growing global demand for its finite fossil fuel reserves, it is looking also to capitalize on renewable energy sources including solar power generation. However, the high ambient humidity, high annual average surface temperature, high atmospheric aerosols including haze, secondary organic aerosols and dust particulates, all negatively impact the efficiency of solar power generation technology. We will present over ten years of Aerosol Optical Thickness (AOT) measurements from both ground and satellite based remote sensing data from NASA's Aerosol Robotic Network (AERONET) and Multi-angle Imaging SpectroRadiometer (MISR) instrument onboard the TERRA satellite. AOT is a measure of the atmosphere's ability to attenuate incoming solar radiation. As AOT increases, surface insolation decreases which in-turn decreases the theoretical limit for solar power generation. The data shows a net positive trend in AOT of >1% per annum over most of the Arabian Peninsula, including Qatar. The positive trend is associated with increased intensity of dust events, but not necessarily in the frequency of the events. The trend is observed over the operational spectral range of Photovoltaic (PV) cells (340-1020 nm.) The AOT trend is positive for all months of the year, except November, but exhibits a strong seasonal signature that indicates the dusty months are becoming dustier (March through July) and less productive for solar power generation. Trends in the angstrom parameter, an indicator of the size of the atmospheric aerosols, during the less dusty winter months, indicate an increase in the average size of the atmospheric aerosols, i.e. the winter months too are becoming dustier. Work continues on quantifying the net impact of the observed trend on solar power generation.
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A Systematic Approach To Carbon Footprint Reduction Stategries In Industrial Parks
المؤلفون: Dhabia Al-mohannadi and Patrick LinkeGlobal concerns of the effects of increased carbon dioxide emissions have pushed policy makers to adopt strict emission targets .The introduction of such targets will require strategies to achieve them in efficient ways. In Qatar, the world highest per capita carbon emitter, stationary emission sources are responsible for the majority of the country's footprint. Concentrated in industrial parks or clusters emissions cuts would be more significant and efficient to achieve as part of a national emission reduction strategy. Conventional mitigation techniques involve fossil fuel replacement, increasing energy efficiency and the use of carbon capture and sequestration. This research proposes an alternative method based on utilization or conversion of carbon dioxide within the industrial city. Carbon dioxide can be chemically or biologically converted into fuel, polymers, food supplements, fodder or another value added product could be used in applications of enhanced oil and gas recovery. Based on concepts of classical network design and Industrial Ecology (IE), a systematic approach was developed to obtain a cost-optimal network of carbon reduction. The integrated analysis of utilization options together with the capture, separation, compression and transmission of carbon dioxide will be required to determine the most economically attractive footprint reduction solutions. The optimization was illustrated using a case study.
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Power Monitoring In Integrated Circuits
المؤلفون: Anas Al BastamiPower monitoring is needed in most electrical systems, and is crucial for ensuring reliability in everything from industrial and telecom applications, to automotive and consumer electronics. Power monitoring of integrated circuits (ICs) is also essential, as today ICs exist in most electrical and electronic systems, in a vast range of applications. Many ICs have functional blocks across the chip that are used for different purposes. Power ICs also have multiple circuit blocks, each performing their own function. Measuring circuit block currents in both analog and digital ICs is important in a wide range of applications, including power management as well as IC testing and fault detection and analysis. For example, the presence of different kinds of faults in IC circuit blocks during IC fabrication causes the currents flowing through these circuit blocks to change from the expected values. There has been general interest in monitoring currents through different circuit blocks in an attempt to identify the location and type of the faults. Previous works on nonintrusive load monitoring as well as on power-line communications (PLCs) provide motivation for the work presented here. The techniques are extended and used to develop a new method for power monitoring in ICs. Most solutions to the challenge of measuring currents in different circuit blocks of the IC involve adding circuitry that is both costly and power consuming. In this work, a new method is proposed to enable individual measurement of current consumed in each circuit block within an IC while adding negligible area and power overhead. This method works by encoding the individual current signatures in the main supply current of the IC, which can then be sensed and sampled off-chip, and then disaggregated through signal processing. A demonstration of this power monitoring scheme is given on a modular discrete platform that is implemented based on the UC3842 current-mode controller IC, which can also be used for educational purposes.
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Optical Properties And Surface Structure Of Anatase Tio2 For Solar Cells
المؤلفون: N.h JufairiTitanium dioxide (TiO2) films have been prepared by sol-gel dip coating technique, using titanium isopropoxide (TIP) as precursors. The structure and the phase of TiO2 films were analyzed by x-ray diffraction (XRD) and showed that films were anatase. Optical properties of the films were characterized by ultraviolet-visible (UV) spectroscopy. The optical band gap was calculated for anatase film layers 50, 100, 150 and 200nm as 3.95, 3.87, 3.75 and 3.70eV, respectively. The refractive index of these films was computed by ellipsometry which were in range from 1.9 to 2.3 at a wavelength range from 380 to 600nm. The thickness of the films was obtained from ellipsometry as of 58nm per one dip. The surface of TiO2 thin films were investigated by sanning electron micropscpe (SEM). The images obtained by SEM show cracks and shrinkage particles in the film. Whereas, the images obtained by atomic force microscope (AFM) showed a homogeneous distribution of elongated shapes of nanoparticles through the film. In addition, the composition of TiO2 thin films checked via energy dispersive spectrometer (EDS), which found small amount of Ti. The results showed that anatase titania (TiO2) nanomaterials have a promised potential for applications in solar cells.
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Synthesis Of Transition Metal Nanoparticles Using Combustion Based Techniques
المؤلفون: Anchu Ashok, Anchu Ashok, Anand Kumar and Yussuf Olasunkanmi KutiSolution combustion synthesis (SCS) is a widely used technique for synthesizing variety of high purity oxide nanoparticles. Two basic modes for combustion synthesis are the self-propagating high temperature synthesis (SHS) and Volume Combustion Synthesis (VCS). The first method is based on the reaction that is locally ignited by an external source (laser, tungsten coil etc) which ends up with an exothermic redox reaction in a self-sustained manner without requiring any further energy for the combustion. Second method is the uniform heating of the entire sample in a controlled manner using a constant heat until the reaction occurs simultaneously throughout the volume. SCS typically involved a self-sustained reaction in a homogeneous solution of oxidizer (metal precursor) and oxygen containing fuels (urea, glycine, hydrazine etc). The selection of fuel is based on the reactive groups such as amino, hydroxyl and carboxyl bonded to a hydrocarbon chain. In our total work, we used two modes of synthesis: VCS and ILCS (impregnated layer combustion synthesis) to synthesize transition metal nanoparticles. The precursors used in this work were Nickel nitrate hexahydrate, Ni(NO3)2.6H2O, Copper nitrate hexahydrate, Cu(NO3)23H2O, Cobalt nitrate hexahydrate, Co(NO3)2. 6H2O and Glycine CH2NH2COOH. The ratio of metal nitrates and glycine were optimized to give pure metals of high surface area. The precursors were thermally analyzed using TGA/DTA to understand the metal phase development with increasing temperature. Phase Composition and average particle size were analyzed using XRD and the specific surface area of the synthesized particle was calculated using BET method, while its morphology was analyzed by SEM. The objective of our work is to synthesize nanoparticle with high surface area, selectivity and reactivity, which will be more suitable to be act as catalysts for electrochemical reaction in the conversion of CO2 to valuable products The XRD calculations indicated crystallite size to be in the range of 8nm - 15 nm indicating small nanoparticles with high surface area suitable of catalytic applications. The XRD profile of Copper-Nickel in glycine for different stiochiometric ratios shows the presence of pure alloy of Copper Nickel at its higher value of ?, say it as 1.75. The multiple peaks in XRD for its lower stiochiometric ratio indicates the presence of oxide. The objective of our work is to synthesize nanoparticle with high surface area, selectivity and reactivity, which will be more suitable to be act as catalysts for electrochemical reaction in the conversion of CO2 to valuable products The large surface area for Copper Nanoparticles were synthesized first which having large surface active sites, they become excellent catalysts in metallurgical and petrochemical Investigation has been done based on the basic mechanism to describe the phase transformation in the combustion front. The SEM analysis pointed a remarkable change in the particle distribution, grain size, porosity and its microstructure by changing the oxidizer/ fuel ratio These nanoparticles are currently being investigated for catalytic reduction of CO2 to valuable chemicals.
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Thermodynamic Analysis Of Heat And Mass Transport Phenomina In Phase Change Regenerators With Conductive Packing
المؤلفون: Abdelhakim Mohamed Hassabou, Markus Spinnler and Wolfgang PolifkeThis paper discusses a comparative study on the role of conductive packing in Humidification-Dehumidification (HDH) solar desalination cycles under steady state conditions. Experimental and theoretical studies have been performed at the Technical University of Munich, Germany on HDH desalination system equipped with phase change material (PCM) encapsulated in spherical plastic shells and used as a conductive packing media in the evaporator and condenser. Moreover, a solar collector and an external PCM thermal storage are used to drive the HDH plant. The external PCM thermal storage is used to guarantee continuous operation of the plant day and night round the clock under the transient behaviour of solar irradiation. The objective of using PCM elements in the evaporator and condenser was for heat storage as a backup during cloudy hours or for part-time night operation. During analysis of steady state conditions, it was discovered that the PCM packing media seem to enhance their thermal performance through locally establishing multiple-effects of heating/humidification (MEHH) and cooling/dehumidification (MECD) while air passing through the successive packing layers in the evaporator and condenser respectively. The multiple-effect phenomena are attributed solely to existence of conductive packing media, which act as heat and mass exchangers. Thus, the focus of the study lies on the thermal conductivity rather than the thermal capacity or solid-liquid phase change processes of the packing in the two columns. The performance of the evaporator and condenser technologies filled with PCM as a conductive packing was examined experimentally in comparison with empty spherical shells with the same size as well as with a conventional industrial plastic packing with high specific surface area. Comparisons were made between different packing types under similar operating conditions to examine the thermal behavior of the evaporator and condenser at atmospheric pressure. Transient simulation models for the individual components in the HDH system have been established and validated against experimental measurements. Using both experiment and simulation, a detailed heat and mass transfer analysis for the performance of the evaporator and condenser over a wide range of operation conditions under steady state has been performed using different types of packing materials. Furthermore, a yearly parametric analysis for the whole HDH plant has been performed under real weather conditions for two locations in Egypt. The overall performance analysis focuses on the optimum operation conditions of the HDH system, with optimum conductive filling material, with and without external PCM thermal buffer.
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Qatalum's 1st Cut Spl; Treatment And Applications
المؤلفون: Omar Al-jarod and Aboubakr AbdullahSpent Pot Lining (SPL) is produced in thousands of tons annually as a waste from the aluminum industry. SPL is classified into two types, 1st and 2nd Cut SPL. The 1st cut, which is the material under investigation in this study, is a contaminated graphite/ceramics material (50 - 60% of graphite) that is used in lining the electrolytic cell within which aluminum is produced by the reduction of molten Al2O3. 1st Cut SPL is considered as a hazardous material since it contains many other contaminants such as fluorides, cyanides, lead and chromium in addition to its production of flammable gases when it comes in contact with water e.g. ammonia, phosphine, hydrogen and methane. The aim of this study is threefold: (i) fully characterize the 1st Cut SPL produced by Qatalum in Qatar to help in creating the materials safety data sheet (MSDS), (ii) chemically treat this 1st Cut SPL in order to extract the graphite component to use it in other applications in addition to the Cryolite and finally (iii) use the extracted graphite in removing heavy metal ions from aqueous solutions. In this work, the first treatment for 1st Cut SPL was washing it with deionized water. The produced gases were collected in gas bags and characterized using GC-MS which confirmed the evolution of H2 gas when the 1st Cut SPL comes in contact of water. The second step was washing the 1st Cut SPL powder several times with organic solvents to dissolve the existing organic compounds and characterize the eluent using HPLC-MS technique to identify the dissolved organics. A thermal treatment to get rid of the undissolved organic materials was done. Next, surface characterization was carried out for the dried powder which confirmed the absence of any organic materials. Later, the powder was treated with cycles of different concentrations of NaOH, HNO3 and deionized water to remove the remaining inorganic contaminants. The eluents, resulted from the chemical treatment and washing processes, were collected and analyzed using HPLC-MS and ICP. The purity of the produced graphite powder was characterized using XRD to check its purity. The produced graphite powder was functionalized through boiling in 1:1 of H2SO4 : HNO3, washing with deionized water, hot NaOH and finally with deionized water to increase the carboxylate groups on the graphite surface which increases the negative charge on the graphite's surface once mixed with water. The functionalized graphite was proved to Cu ions from aqueous solutions at different pH values with efficiency close to 100 % at pH 10.
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Synthesizing New Anodes From Qatalum's 1st Cut Spl
المؤلفون: Abdullah Hani Holozadah, Aboubakr Abdullah, Mufeed Odeh and Chris Devadas,Aluminum industry produces hundreds of tons of spent pot lining (SPL) waste every year. SPL is classified into two types: 1st cut and 2nd cut. The 1st cut SPL which is the material under study in this work is mainly composed of graphite (~ 60%), ceramic material and Al metal (~ 10%). On contrary with the 2nd Cut SPL, there is a consensus that the 1st cut SPL is a hazardous material and must be treated before dumping it in a landfill. Recycling it will be more beneficial if possible. The aim of this study is using the extracted graphite material from the 1st Cut SPL to produce new carbonaceous anodes for the Al molten electrolytic cells. The idea is to mix the extracted graphitic material with new binder materials e.g. o-phenylenediamine (C6H4(NH2)2), polyaniline or phosphorous (also a mixture of two or all of them) to increase the thermal and chemical stability and electrical conductivity of these new anodes compared to the currently used anodes in Qatalum (Qatalum uses 70% petroleum coke + 30% Coal Tar Pitch (CTP) as a binder). This might result in extending the life time of the carbon anodes and decrease the number of carbon dioxide kilograms that are released per a ton of produced Al metal. For comparison, the anodes were synthesized using the extracted graphite material from the 1st cut SPL, a commercial one and a petroleum coke (PC). The thermal properties were characterized using thermal gravimetric analysis. Also, the electrical conductivity of the new produced anodes was measured. In addition, the impedance spectra for the new anodes were measured at different temperatures and compared to the currently used anodes at Qatalum. Results have shown that anodes prepared from 50% of the extracted graphite with 10% of the commercial graphite and 40% coal tar pitch have impedance of one order of magnitude lower than the currently used anodes in Qatalum.
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The Use Of Wireless Sensor Networks In Agricultute A Tool For A Sustainable Food Supply In The Arab World
المؤلفون: Mustafa Ibrahim AliTHE USE OF WIRELESS SENSOR NETWORKS IN AGRICULTUTE A TOOL FOR A SUSTAINABLE FOOD SUPPLY IN THE ARAB WORLD In this paper some ideas of how to apply the technological advancement of the wireless sensor networks (WSN) in agriculture as a tool for food security is discussed. This will include some examples where the technology can be applied, what changes can this technology brings to the traditional farming, which can help within the solution of the Arab World food security problems. This will help the region to develop and be part of the global strategy for the World food security. WSN features of having a low power consummation nature with different options of using different energy sources will make it as the just technology suitable in a remote and less or without infrastructural bases environment for many countries within the region. The applications of WSN which are suitable for the purpose will be discussed. Keywords: WSN, Food Security, Agriculture in Arab region, WSN Farmer Kits Tool, Energy Sources. Introduction Arabic countries are naturally rich, many countries within the region have a wide virgin land. But unfortunately some of these countries have been a focus in term of food shortages for long time which cause by many factors like land degradation, water crisis, land deals, climate change, agricultural disease, governing system, wars, population growth, land use change, living style change, high prices and lack of technology. As technology has rational parts in solving the most difficult problems for today's society, WSN can be applied in agriculture to reduce or solve this problem. Use of WSN in Agriculture as a solution As traditional farming is the lead in the region, people use their own human sense to perceive the surrounding to investigate the soil and predict the weather. But the remote sensing of the WSN as an activity of recording, observing, perceiving objects or events, wirelessly these happenings are processes and analyzed in a real time. The idea of applying this technology is to be adopted in different applications shortly can be said here. *Soil Investigation by using the specialized soil test sensor detectors to determine the fertility of soil nutrient deficiencies, elements like Nitrogen is very important for plants. *Weather Prediction by using a web data from WSN can be transmitted enabling a remote online interactive retrieval access, and then these data can be shared with the farmers. *Detection of ground water using WSN the level and the amount of sufficient water can be detected before planting. *Using the WSN the water and the area can be controlled during irrigation which will help in reducing the energy consumption. *Food storage system will be advanced by the use of WSN in knowing usage validity time and the space of storing. *Knowing where how and when to deliver what kind of product by using WSN will help in the logistical distribution of crops. *Farming Dissemination by using an integrated WSN tool kit messages can be disseminated.
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Source Term Modeling Of Cryogenic Liquid Vapor Formation By Experimental Investigation - Evaporation Regime And Convection Effect
المؤلفون: Asma Sadia, Waqas Nawaz, Tomasz Olewski and Luc VechotSafe handling, storage and transportation of Liquefied Natural Gas (LNG) has been the root concern in the process industry due to the growing demand for ecological and clean alternative energy namely natural gas. Due to economic advantages in transportation, natural gas is transported in the liquid form. This calls for a thorough research in LNG safety due to its hazardous flammability properties. The study of consequence of loss of containment of LNG is critical to the risk assessment for LNG facilities. This is especially important for Qatar since it is the largest exporter of LNG accounting for about 32 % of the global LNG exports as of 2013. It is important to conduct fundamental and applied research to enrich the knowledge of LNG related safe operations. It is necessary to be able to model consequences of accidental LNG spill to assure sustainability of its production. The loss of containment of LNG leads to the generation of flammable vapor that gets dispersed in the atmosphere. This phenomenon is the same for any cryogenic liquid and is usually split into two stages: vapor formation (source term) and atmospheric dispersion. The vapor formation rate will be determined by its storage conditions (temperature and pressure) and the condition of the release (geometry and location of the dike/bund and the release point, ground temperature and weather data). During the dispersion stage, the behavior of the fluid is controlled by the atmospheric conditions (atmosphere stability class, wind speed, air temperature). The division of the phenomenon into two stages is a convenient approach from modeling perspective. Historically, less attention has been given to source term modeling. Simultaneously, the output of source term is the input into dispersion modeling, and thus, if the former is not accurately estimated the latter cannot be. Moreover, source term modeling is very complex and it cannot be well defined and validated since there is a lack of useful experimental data. This work aims at filling the gap and improving the experimental database. The scope of this part of project includes study of the convective heat flux to the cryogenic liquid pool, which is a part of source term model and study of evaporation regime. It also looks at different scales (small and medium) of experiments and the effect of spilled liquid composition. Currently, experimental results are available for spill of liquid nitrogen at small (0.001 m3) and medium scale (0.023 m3). The aim is to study the transition to evaporation regime and to validate existing evaporation models. It was determined that at the small scale five of the six models were valid but at the medium scale only one model gave close prediction. The deviation increase with scale up, which could be expected as most of the existing models were developed utilizing small scale experimental data. In near future, more investigations will be carried out at the large scale for better understanding of the phenomena.
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Role Of Aromatics In Synthetic Fuels
المؤلفون: Muaz Selam, Wajdi Ahmed, Moiz Bohra, Hafis Mohamed, Rehan Hussain and Nimir ElbashirThis paper describes our investigation into the effects of adding aromatic compounds to synthetic aviation fuels on the performance of these fuels. The work was done as an undergraduate research (UREP) project and was an extension to our group's previous studies which were aimed at characterizing blends of conventional and synthetic aviation fuels [1] and identifying optimum paraffinic building blocks for SPK [2]. Aromatics play a key role in aviation fuels as they enhance the density and elastomer swelling properties of these fuels. However, they are absent from synthetic gas-to-liquids (GTL) derived aviation fuels such as synthetic paraffinic kerosene (SPK) and thus must be added in from another source. In the first part of this study, standard analytical tests were conducted on blends of SPK and aromatic additives (styrene and Shell A150) in different concentrations from 0 to 25 % to measure certain fuel properties (i.e. density, flash point, freezing point, heat content and viscosity) using relevant ASTM procedures. The measured properties were then compared with the desired values for certification according to the ASTM D-1655 and D-7566 standards for conventional and hybrid (i.e. mixtures of oil-derived and synthetic fuels obtained from either natural gas or coal) jet fuels, respectively. In particular, ASTM D-7566 specifies the use of the 50-50 synthetic fuel blend with jet A-1; our group's efforts are aimed at increasing the workable synthetic ratio in the fuel. The experimental work was conducted in the Fuel Characterization Lab at Texas A&M University at Qatar. The data generated from these experiments was used to identify correlations between blend compositions and properties. In the second part of this study, small amounts (i.e. 1 vol %) of specialty aromatic compounds (such as benzaldehyde) were added to the blends from the first part of the study, specifically to enhance the elastomer swelling characteristics of these blends. This is a crucial property of aviation fuels as it ensures a tight seal in fuel tanks, thus preventing potentially catastrophic leakages. The added aromatic compounds were identified based on a Hansen solubility parameter analysis, and it was found that their addition favorably increased both the density and elastomer swelling characteristics of the SPK. Notably, three of the blends tested outperformed the elastomer swelling characteristics of conventional Jet A-1 by about a factor of 2. With respect to freezing point, viscosity, heat content, and flash point, the performance of all of the blends tested were in agreement with ASTM standards. These experimental results demonstrate the favorability our approach to synthetic fuel design i.e. the focused introduction of additives to improve the performance of synthetic fuels to standards at par with or, in some cases, surpassing those of conventional jet fuel.
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Fiberglass Casing And Tubing In Highly Corrosive Environments
المؤلفون: Ahmed Abdul RaufThe UER formation in the Dukhan Field, Qatar has an aquifer associated with it. The formation water and sour crude associated with the formation and aquifer lead to many corrosion-related problems, and casings are being replaced at an almost bi-annual rate. Our research proposal was to replace these with fiberglass casing and tubing. Any tubing and casing that is replaced would need to withstand similar pressures and temperatures as the original steel and fulfill the same functions. Despite plenty of mechanical testing data available on fiberglass as a material, there is very little existing research on fiberglass tubing and casing. This was essential as the manufacturing and therefore composition of fiberglass varies greatly depending on the application. Therefore field-specific, quantative and mechanical research on fiberglass casing and tubing is required. Before conducting physical research, we compiled industrial advantages of fiberglass through fiberglass manufacturer guarentees and product ratings. In the laboratory, we re-established the high resistance to corrosion of fiberglass, and demonstrated comparable resistances to compressive pressure and shear of fiberglass piping to that of steel. In some cases, the fiberglass even proved to perform better and failed at a higher pressure than steel. Latex cement was used to cement the casing and tubing models together, this cement is oil wet and bonds to the inner surface of the fiberglass piping. The cement bonded very well and held even after until the piping had failed under compression. Piping made of fiberglass would not only be cheaper to transport and install, but also more resistant to corrosion, lighter to handle and easier to push into deviated or horizontal wells. (Williams 1987). Overtime, there will be a lower cost of corrosion-control and remediation. Indeed, fiberglass casing and tubing can be employed in the place of steel not only in the UER formation, but in a large number of highly corrosive environments, both down hole and on surface. The use of fiberglass instead of steel casings will not only reduce the affect on the environment due to pollutants, but also contribute to material safety and cost savings.
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Investigating New Imaging Modality: Magnetic Particle Imaging
المؤلفون: Ahmed El Ghamrawy and Steven M. WrightMagnetic Particle Imaging (MPI) is a newly found imaging modality. It utilizes superparamagnetic materials as tracers in the blood stream to obtain very high resolutions. MPI promises to have high sensitivity, high spatial resolution and no radiation compared to other imaging modalities. Most commercially available MRI tracers (used for MPI for now) are all non-harmful when compared to Iodine (used for CT scan) and Gadolinium (used for MRI). MPI research is divided into three categories: MPI scanner development, superparamagnetic materials development, and image reconstruction techniques. In this project a small scale LabView-based system will be developed for use on small lab created phantoms, using 25 nm superparamagnetic iron oxide (SPIO) particles. At first a relaxometer will be developed, the imager will come as the next step. Transmitting and receiving signals will be implemented using LabView and a National Instruments PXI-1033 Chassis. Lab-built coils will be used to send the excitation signal and receive the signal induced by those SPIO's. The objective of this project is to be introduced to a new imaging modality that can have various applications and at the same time considered safe. The system being built is considered inexpensive and shows most of the aspects of how magnetic particle imaging works, starting with the physical phenomena, superparamagnetic nanoparticle properties and relaxation, signal generation and acquisition, and an introduction to the hardware of MPI. The system can be used to introduce engineers and engineering students to the MPI physical phenomena.
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Screening Of Some Qatari Plant Extracts For Anti Fungal Activities Of Plant Pathogenic Fungi
المؤلفون: Ibtihal Mohamed and Talaat AhmadThe present study aimed to evaluate the antifungal activity of three desert plants extracts grown naturally in Qatar: (Al-rayhan) Ocimum basilicum, Shafallah (Capparis spinosa) and Qwaif(Prosopis juliflora)to study their inhibitory effect against three pathogenic fungi: Aspergillus niger, Fusarium oxysporum and Giberella baccata. Samples were collected from Qatar University farm. Filter disk method was used for antagonistic study and four chemical solvents: distilled water, n-butanol, ethyle acetate and chloroform were used to extract the plant materials. The fungi were diluted by DMSO and then treated by 0,5, 10 and 20 mg/ml concentration of extracts in addition to the control group. The study revealed thatCapparis spinosa and Prosopis juliflora extracts had the highest inhibitory effect against Aspergillus niger, Fusarium oxysporum and Giberella baccata while Osmium basilicum of n-butanol and chloroform extracts showed no significant effecton Gibberella baccata. Distilled water and ethyl acetate extracts of Osmium basilicumat 20% concentration showed high inhibition against Gibberella baccata. The study revealed that ethyl acetate at 20% concentration significantly reduced Aspergillus niger growth when treated with Prosopis juliflora and Capparis spinosa extracts (0.88 and 0.93 cm), respectively. Ocimum basilicumalsosignificantly minimizedthe growth ofFusariumoxysporum (0.92 cm) using the same solvent concentration. It could be concluded that the studied plants are promising in the treatment of pathogenic fungi when treated using the appropriate solvents and concentration.
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Dna Barcoding Of Lizards (reptilia, Squamata) Of Qatar
Recent rapid development in Qatar has brought awareness and recognition of the importance to catalogue, describe and preserve its biodiversity. Traditional methods of using morphological characteristics for species identification, although important, requires years of experience and is in need of complete specimens before identity is certain. Recent worldwide endeavor of DNA barcoding by using a segment of the mitochondrial gene cytochrome oxidase c 1 (CO1) to describe all species in the world, has gained recognition and popularity. In this student-centered research supported by Undergraduate Research Experience Program (UREP) of Qatar National Research Fund (QNRF), the objective is to sequence the barcoding gene CO1 of the lizards in Qatar and to compare the sequence among closely related species to facilitate future identification. The final results of this study will make available the barcode sequences of CO1 to be included in the GenBank database. Lizard species were collected across Qatar and photographs were taken for appropriated morphological identification. About 0.5 cm3 of muscle tissues were obtained from each specimen for DNA extraction. Currently between 8 to 12 different primer pairs suggested in literature and primer pair combinations were used for 7 species and a variety of programs of polymerase chain reaction (PCR) were employed in order to amplify the segment of gene of about 650 bp. Among the successfully amplified sequences from the 7 species currently analyzed, three species, Trachylepis septemtaeniata, Mesalina brevirostris, and Uromastyx aegyptia produced PCR products. To eliminate the presence of multiple sequences in the PCR product, PCR fragments were ligated to cloning vector in order to amplify one single sequence for each species. The current total success rate (<43%) based on the primer sequences obtained from publish results and from internal primers developed in this study further supports that the universal primers for reptiles are difficult to develop due to deep phylogenetic divergence. Future studies seeking universal primers should focus on candidate genes that evolve more slowly than CO1 gene to ensure higher homology of sequences among the reptilian species.
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Bacteriophage Diversity In The Ecology Of Qatar
المؤلفون: Umm-kulthum Ismail Umlai and Annette VincentThe Science Education Alliance (SEA) Phage Hunters Advancing Genomics and Evolutionary Science, or PHAGES, is a national initiative in the United States, funded by the Howard Hughes Medical Institute (HHMI) and led by Professor Graham Hatfull from the University of Pittsburgh. This project is built around the discovery and analysis of mycobacteriophages in the biodiversity of the United States. For the first time, this research is being done in Qatar at Carnegie Mellon University to discover the possible existence of bacteriophages within the soil and sand of this Gulf State. The aim was to isolate and purify the phages present within the local ecology to be used as subjects of phage related medicinal therapy. Mycobacterium smegmatis (M.smeg) was used as the host bacteria strain in order to identify the presence of its phages within the sand and soil. This host was chosen due to its non pathogenic nature, fast growing ability and for being a universal host. M.Smeg also has physiological similarities with pathogenic species from the same family; M.tuberculosis causes tuberculosis, and M.leprae causes leprosy. Such efforts are intended to allow us to better understand the mechanisms by which to treat such bacterial diseases using phage therapy as opposed to using increasingly ineffective drugs. Although M.smeg failed to act as a host for the isolated phages from local environmental samples, future works to identify the suitability of other bacterial hosts such as Arthrobacter sp. for these phages will be carried out. Furthermore, analysis of the microbial composition of environmental samples will be conducted to identify specific bacteria hosts that exist in Qatar's ecology.
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New Hereditary Hearing Loss (hhl) Genes/mutations Identified By High Throughput Technologies In The Qatari Population
Objectives: Hereditary Hearing Loss (HHL) is a common genetic disorder accounting for at least 60% of prelingual deafness in children. The long tradition of consanguinity, which is widespread among populations of Arabian Peninsula, increases the prevalence of HHL. It is one of the most frequent causes for school failure in Qatar. GJB2 gene plays a worldwide major role in HHL recessive forms while in Qatar it has a minor role thus strongly suggesting the presence of additional causative genes. To overcome the remarkable genetic heterogeneity of HHL in Qatar population, an extremely powerful 2 steps "gene-identification strategy" was designed (Figure 1). STEP1 consists in a screening of 96 HHL genes by targeted re-sequencing (TS). Positive cases contribute to define an accurate molecular epidemiology picture while negative ones undergo STEP2, a combination of linkage studies and whole exome sequencing (WES) or directly to WES (depending on pedigree size). Methods: Ion Torrent (Life Technologies) (400X of mean target coverage and 581.000 Kb of targets size) was used for STEP1 and Illumina genotyping and Ion Proton (Life Technologies) (90X of mean coverage and 60Mb of target size) were used for STEP2. Sequencing variants were annotated/filtered according to standard pipelines. This strategy was applied to a first series of Qatari families. Results: STEP1 characterized 53% of Qatari families with HHL leading to the identification of 20 novel alleles in known HHL genes (i.e. GJB2, P2RX2, TECTA, TMPRSS3, LOXHD1, MYO15A, TMC1, TRIOBP, WFS1). STEP2 had already led to the discovery of 1 new gene (BDP1). The p*2625Gluext*11 mutation resulting in an elongation of 11 residues of the BDP1 protein was identified in a Qatari recessive family and its expression in the inner ear was confirmed by immunohistochemistry. Conclusion: This combined and powerful strategy proved to be very successful by explaining several HHL unsolved cases and by defining an accurate molecular epidemiology picture of Qatari genes/mutations. Moreover, this approach will be used for developing a "Qatari tailored" molecular diagnostic assay opening new important diagnostic perspectives for a such heterogeneous disorder as well as for defining targets for new possible therapeutic interventions
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Metformin Reverses Glucose Starvation Induced Endoplasmic Reticulum Stress And Autophagy In The Microvascular Endothelium
المؤلفون: Suparna Ghosh, Samson Mathews Samuel, Hong Ding and Christopher TriggleBackground and Objective: Diabetes Mellitus is associated with a higher incidence of myocardial infarction (MI) and poor prognosis in affected individuals; however, treatment with the oral hypoglycemic drug, metformin, is associated with a reduction in cardiovascular morbidity and mortality. A MI reduces oxygen delivery and results in nutrient/glucose starvation (GS) with micro-vascular endothelial cells (MECs) receiving the initial impact, the effect being more profound in a diabetic individual as glucose levels drop from hyperglycemia to GS. It is, however, not known whether GS triggers endoplasmic reticulum (ER) stress and autophagy in MECs and whether metformin has any effect on GS associated ER stress and autophagy. Thus, protocols were designed to determine whether GS-induced ER stress and autophagic events could be rescued. Methods— Mouse Microvasuclar Endothelial Cells (MMECs) were subjected to GS for 24h in the presence and absence of sodium-4-phenylbutyrate (chemical chaperone, 4PBA, 10mM) or metformin (50µM and 2mM) and western blot analysis was performed to assess the induction of ER stress and autophagy. Immunofluorescence staining was also done to assess LC3B punctae staining in cells, indicating autophagy. Results- GS caused ER stress as evidenced by significant increase in the levels of ER stress markers such as GRP78, ATF4 and CHOP. Significant increases in the levels of LC3A-II and LC3B-II and an increase in the level of LC3B punctae staining in glucose starved cells confirmed autophagic activation. Treatment with 10mM 4PBA significantly reversed GS induced ER stress and subsequent autophagy. The effects of varying concentrations of metformin (10µM-2mM) were studied. Metformin (2mM) significantly reversed ER stress and autophagy in glucose starved endothelial cells while lower concentrations that were in the therapeutic range had no effect. Markedly decreased LC3B punctae staining in metformin treated glucose deprived cells also ascertained the reversal of autophagy. Conclusions— This study demonstrates for the first time that GS induced ER stress and autophagy in the microvascular endothelium can be reversed by metformin, albeit only at mM concentrations. This work has been supported by QNRF grants JSREP- 3- 016-3-009 and NPRP 4-910-3-244.
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Exercise Induced Changes In Erythrocyte Membrane Proteome
More than 30 years ago people have learned that exercise promotes oxidative damage in human tissues. Since then, our knowledge on exercise-induced free radical production and their effect has advanced markedly. In the beginning research has mainly focused on detrimental effects of exercise-induced free radical production (e.g. oxidation of macromolecules); however today a new era of redox biology exist that centers on the cell-signaling effects of exercise-induced free radicals, such as reactive oxygen species (ROS) that were shown to play a crucial role in muscle adaptation to exercise. Erythrocytes are rich in membrane polyunsaturated free fatty acid content and have high cellular concentrations of oxygen and haemoglobin that makes them susceptible to ROS induced damage. However, mild oxidative stress has beneficial effect by increasing endogenous antioxidant mechanisms. Thus, in the present work we have used sensitive mass spectrometry techniques to assess the potentially beneficial oxidative modifications of erythrocyte membrane proteins in response to exercise. We have recruited 3 healthy volunteers and their blood was drawn before exercise, immediately after and few hours after exercise. Erythrocyte membranes ("ghosts") were prepared and membrane proteins isolated. Proteins were then separated by 1-D gel electrophoresis, digested with trypsin and peptides analyzed by Orbitrap ELITE coupled with the Easy n-LC II for nano LC-MS/MS. The acquired data was searched with Proteome Discoverer 1.4 against Homo sapiens database to reveal the changes in the erythrocyte membrane proteome. Furthermore, data acquired was also searched through the database using the comprehensive workflow that included several dynamic modifications of peptides, including N-terminal carboxymethyl, C-terminal oxidation and terminal independent oxidation and trioxidation of peptides. The results obtained revealed several proteins that have translocated from the cytoplasm into the membrane following exercise. Moreover, numerous proteins showed exercise dependent modifications and up/down regulation. Exercise induced proteome changes were demonstrated to play an important role in several signaling pathways related to healthy living and lifestyle.
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The Immune-related Role Of Braf In Melanoma
BACKGROUND. The existence of a dichotomy between immunologically active and quiescent phenotypes has been recently recognized in several types of cancer. The activation of a Th1 type of immune signature has been shown to confer better prognosis and likelihood to respond to immunotherapy. However, whether such dichotomy depends on the genetic make-up of individual cancers is not known yet. In melanoma, BRAF and NRAS mutations are frequently acquired during development. We recently proposed a genetic classification of melanoma metastases based on copy number variation and consistency of genes expressed in vivo and in vitro. We found that genes consistently expressed by 15 melanoma cell lines (CMs) and their parental tissues (TMs) were critical for oncogenesis and their respective copy number influenced their expression. Most importantly, these genes were able to categorize melanoma metastases into two divergent phenotypes (TARA class: transcriptional adjustments related to amplification/deletions): one with prevalent expression of cancer testis antigens, enhanced cyclin activity, WNT signaling, and a Th17 immune phenotype (Class A) and the other one with prevalent expression of genes associated with melanoma signaling and with a Th1 immune phenotype (Class B). An intermediate third class (Class C) was further identified. Here, we tested whether these phenotypes might be at least in part explained by BRAF and NRAS mutations in melanoma. METHODS. One-hundred-thirteen melanoma metastases were processed for microarray analysis and BRAF and NRAS sequencing. Allele-specific PCR (AS-PCR) was also performed to exclude low-frequency mutations. RESULTS. Comparison between BRAF and NRAS mutant versus wild type samples identified mostly constituents or regulators of MAPK and related pathways. When testing gene lists discriminative of BRAF, NRAS and MAPK alterations, we found that 112 BRAF-specific transcripts (p<0.01) were able to distinguish the two immune-related phenotypes already described in melanoma, with the poor phenotype associated mostly with BRAF mutation. Noteworthy, such association resulted stronger in samples displaying low BRAF mRNA expression. When testing NRAS mutation and expression, we could not find the same association. Class comparison between BRAF mutant samples displaying high levels of BRAF mRNA expression and wild type samples revealed that there is much more similarity between the two than with the low expressing BRAF mutant samples. To gain further insights concerning this surprising finding we performed functional interpretation analysis of the 6296 genes differentially expressed between BRAF mutants with high and low expression of the same gene; deregulated pathways included IL-2 and JAK/Stat signaling pathways, supporting the immunoregulatory role of BRAF. CONCLUSION. This study suggests that BRAF mutation-related specific transcripts associate with a poor phenotype in melanoma and provide a nest for further investigation.
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Prevalence Of Conventional Versus Non-conventional Cardiovascular Risk Factors In Patients Following Percutaneous Coronary Intervention For Acute Coronary Syndrome
المؤلفون: R. Jay Widmer, Mohamed Gomaa, Martin Reriani, Timothy Morgenthaler, Jassim Al Suwaidi and Amir LermanTraditional risk factors often fail to correlate with event incidence, thus there is a need for novel risk assessment in order to predict events and guide therapy in patients with acute coronary syndromes (ACS) following percutaneous coronary intervention (PCI). Peripheral endothelial dysfunction (PED) and obstructive sleep apnea (OSA) can both predict cardiovascular events, yet the prevalence of PED and OSA in patients hospitalized for ACS following PCI is unknown. Patients in the USA (n=65) and Qatar (n=352) were consented, enrolled following PCI for ACS, and underwent endothelial function testing (EndoPAT) on day 5 and home OSA testing (WatchPAT) following PCI. Baseline demographics at the time of patient admission showed only a modest prevalence of traditional CVD risk factors (Figure 1). The prevalence of PED (defined by EndoPAT<2.0) in this cohort was 73% (mean EndoPAT score of 1.8+0.5), and that of OSA 82% (Apnea Hypopnea Index>5; Figure 1). These functional, non-traditional risk factors were significantly more prevalent (p<0.0001) in this population than traditional risk factors, such as prior MI (6%), hypertension (52%), hyperlipidemia (47%), BMI>30 (43%), diabetes (36%), smoking (30%), CHF (1%), or family history of CVD (37%). Prevalence of both PED and OSA was present in 57% of participants. The current study demonstrated a higher prevalence of PED and OSA following ACS than the traditional CVD risk factors, underscoring their potential value for patient management. Detection and treatment of these functional risk factors may predict events and guide therapy in patients with ACS.
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Infection Rates And Phylogenetic Analysis Of Hepatitis G Virus (hgv)/gb Virus C (gbv-c) Among Qatari Blood Donors
Background: A new immerging nonpathogenic single stranded human RNA virus known as GBV-C/HGV was discovered in 1995. Both GBV-C virus and HCV have similar genome, but they replicate in different cell types. The incidence of GBV-C infection has been studied worldwide, however, to our knowledge; no previous studies were conducted in Qatar, thus the objectives of this study are: (i) to determine the rate of GBV-C infection in Qatar among healthy blood donors and liver-diseased patient and (ii) to determine the most predominant GBV-C genotype in Qatar. Methods: 755 blood plasma samples from blood bank (593) and virology section (162) at HMC were collected. RNA was extracted, reversed transcribed, and then subjected for GBV-C detection by nested PCR using primers targeting a 205 bp of the 5' hypervariable untranslated region (5'-UTR) of the GBV-C/HGV. For genotyping, the 5'-UTR PCR product were T/A cloned into pDrive plasmid. The plasmids were transformed into DH5α™, and then plasmids were purified and digested by EcoRI to detect the positive clones. Plasmid were then purified and sequenced. Phylogenetic analysis was conducted by analyzing the 5'-UTR sequence from randomly picked positive clones. The resulted sequences were assembled and analyzed using CLC and MEGA5 software. Results: we found that HGV infection rate among healthy blood donors was 13.5 %, while in liver-diseased patient was 8.6 %. Moreover, there was no significant difference in the GBV-C infection rate among Qatari (13.3%) and Non-Qatari (14.4%) healthy donors. Sequence analysis of 25 5'-UTR PCR amplicons yielded the European genotype (genotype 2) as the most predominant in Qatar. Conclusion: Our results indicate that there is no correlation between GVC- infection rate and other liver-infecting viruses such as HB&CV. Not surprising, genotype 2 was also reported to be dominant in countries surrounding Qatar such as UAE and Kuwait. Finally, we think our results should benefit epidemiologists in the region and may have an impact on the blood screening policy in blood banks.
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"whole Exome Sequencing Of A Family With 3 Sibling Affected By Bicuspid Aortic Valve Disease"
المؤلفون: Cornelia Carr, Despina Sanoudou, M. Dilawar, S. Helmi, Emmeleia Nana, Kholoud Al-shafai, Paul Barton, A. Al Khulaifi and Magdi YacoubBackground: Bicuspid aortic valve (BAV) is the most common cardiac malformation affecting 1-2% people worldwide. Despite its high prevalence, the pathogenesis of BAV is largely undetermined, although gene mutations leading to alterations in cell migration and signal transduction, in conjunction with non-genetic factors such as blood flow during valvulogenesis, may contribute to its formation prenatally. Objective: The determination of genetic factors contributing to the presentation of BAV in a family with three affected daughters. Methods: We applied next generation whole exome sequencing (>3Gigabases per individual) to high quality DNA from the blood samples of the three affected daughters and their unaffected parents. The >36.000.000 reads of each of the 5 individuals were analyzed with the bioinformatics tools Burrow-Wheeler Aligner, SOAPsnp, Sam tools, Varscan, and GATK to identify single nucleotide polymorphisms and insertions/deletions. Results: We identified over 38,000 SNPs and 3,400 Indels in each individual, of which >1,000 and >580, respectively, were novel. Forty one SNPs were detected in at least two of the affected siblings but neither parent, and only 3 of those were detected in all three BAV patients: HFM1 (ATP dependent DNA helicase), TSPAN2 (tetraspanin family member) and TTF2 (transcription termination factor, RNA polymerase II - pre-mRNA splicing regulator). All 3 genes carried exonic, non-synonymous SNVs, with highly significant pathogenicity prediction scores (SIFT, PhyloP, MutationTaster, LRT). Eight Indels were detected in at least two of the siblings, and only one of them was common across all three siblings: CCNL2 (cyclin L2). CCLN2 is a regulator of the pre-mRNA splicing process, as well as inducer of apoptosis, by modulating the expression of apoptotic and antiapoptotic proteins. In our patients it was found to carry a four base deletion affecting a splice site. None of the previously reported BAV-related genes were found to carry a common mutation across all, and unique to the BAV patients of this family. Conclusion: We have detected 4 genetic variants, shared by all three BAV patients but neither parent. These genes have not been associated with BAV to date. Of particular interest is the novel variant in TSPAN2, a gene of largely unexplored function, belonging to a transmembrane protein family known to mediate signal transduction events that play a role in the regulation of cell development, activation, growth, adhesion and motility.
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Alterations Of The Tumor Microenvironment By Her-2-neu-induced Creb Activation And Localization And Hypoxia
Cancer incidence is rising fast in Qatar, including in particular breast cancer. The expression of the oncogenic protein HER-2/neu is associated with an aggressive phenotype, and agents targeting this molecule have been successful in prolonging survival of breast cancer patients. Despite treatment progresses, metastatic breast cancer is still a fatal condition, and mechanisms of HER-2/neu regulation/resistance are not fully explained. Therefore a better knowledge of the dynamic of HER-2/neu regulation would enable to define new generation targeted therapy agents. The cAMP responsive element-binding protein (CREB) is involved in tumor initiation as well as tumor progression, but a link between HER-2/neu-induced transformation, CREB activation and alterations of the tumor micromilieu including hypoxia-mediated increased angiogenesis has not yet been established. Therefore, the effect of CREB activation on angiogenesis and its modulation by hypoxia was analysed in CREBhigh and CREBlow HER-2/neu+ murine fibroblasts in vitro as well as in vivo. Human tumor cells transfected with HER-2/neu or a mutant deficient in HER-2/neu signalling served as controls. By determination the number and density of blood vessels, necrosis and hypoxic areas a decreased tumorigenicity coupled with a reduced angiogenesis, but increased necrotic cells and hypoxic areas was found upon injection of CREBlow vs. CREBhigh HER-2/neu-transformed cells. In vitro, a time-dependent increase of pCREBSer133, but not of pCREBSer121 in the presence of hypoxia was detected, which was dependent on HER-2/neu signalling and accompanied by an upregulation of HIF-1α, GLUT1 and VEGF as well as of cell migration and invasion mediated by an increased expression of metalloproteinases. Under normoxic conditions, CREBhigh, but not CREBlow HER-2/neu+ cells showed a low intracellular pH, which was restored by CREB silencing. This was at least partially increased in the presence of hypoxia and correlated with an upregulation of lactate in the cellular supernatant of all cells. Furthermore, a hypoxia-mediated post-transcriptional modification due to an increased ubiquitination of CREB and altered cellular distribution of CREB was found. Under hypoxia CREB was translocated into mitochondria, which was accompanied by an altered expression of mitochondrial genes and enhanced apoptosis sensitivity. Thus, HER-2/neu-mediated CREB activation and localization is modulated by the hypoxic and acidic tumor microenvironment, thereby affecting the tumorigenic phenotype. In conclusion a link between HER-2/neu-mediated CREB activation and changes in the microenvironment and CREB localization was found, which contributes to the pathogenesis of HER-2/neu-expressing tumors, including mammary carcinoma. HER-2/neu-mediated CREB activation stimulates angiogenesis and hypoxia and is increased during hypoxia thereby causing translocation of CREB to the mitochondria, which enhances the malignant phenotype. Thus, targeting molecules downstream of HER-2/neu, like CREB, appear to be promising targets for the development of novel innovative therapies of HER-2/neu overexpressing tumors.
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Effects Of Rituximab On The Response To Influenza Vaccine In Complete Remission Lymphoma Patients
Hematological Malignancies (e.g., leukemia and lymphoma) are among the top 5 causes of cancer death in the Middle Eastern Countries, including Qatar, Kuwait and Saudi Arabia. The monoclonal antibody rituximab, directed at the CD20 antigen, has become an essential drug for the treatment of Non Hodgkin Lymphoma (NHL). Although transient B cells depletion frequently occurs after rituximab treatment, it usually resolves after 6-9 months. Nevertheless, high frequency of non-neutropenic infections and persistent hypogammaglobulinaemia during follow-up period have been recently reported. However, impaired humoral response to the recall and primary antigens was found in NHL patients during (or few months after), rituximab treatment. Influenza vaccination is generally recommended in lymphoma patients, but few data are available about the activity of this vaccine after rituximab-containing regimens (RCR). It is presently unclear whether patients treated with RCR regain normal immunocompetence after achievement of complete remission. We present integrated data of 3 sequential studies conduced at our Institutions assessing the humoral response to seasonal influenza vaccination (2008/2009, 2009/2010 and 2011/2012 seasons; RIT-01, RIT-02, and RIT-03 studies, respectively) in NHL patients in complete remission (CR) for at least 6 months after treatment with rituximab-containing regimens (RCR). Overall, we found that patients treated with RCR have a significant lack of humoral response to both recall and naive influenza antigens as compared with HV and with cancer patients treated with chemotherapy not containing rituximab. This weakness was associated with depletion of CD27+ memory b cells. To determine early transcriptional changes predictive of immunoresponsiveness and to determine differences in innate immunity activation among patients treated with RCR, HV, and patients treated with chemotherapy without rituximab, PBMC were collected just before and 1 day after vaccination (RIT-03 study). Whole-genome gene expression analysis of these samples using microarray analysis reveals that the intradermal vaccination was associated with dramatic transcriptomic changes in PBMC, already detectable 24 hours after vaccination. These changes underlie modulation of innate response (eg, interferon stimulated genes, NK-releted transcripts) and differs according to the treatment administered (eg chemotherapy with or without rituximab). In conclusions: a) patients previously treated with RCR should be strictly monitored during influenza epidemic season; b) anti-neoplastic treatments containing rituximab result in prolonged and specific immune alterations.
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Lifetime Prevalence Of Common Mental Disorders In Qatar: Using Who Composite International Diagnostic Interview (who-cidi)
Background: Mental Disorders, particularly Depression, are recognised as one of the biggest burden of disease worldwide. Two of the top three burdens of disease in Qatar are mental health related. Yet, there is scarcity of lifetime prevalence data available to understand the impact in this country. Aim: This study uses the WHO Composite International Diagnostic Interview (WHO-CIDI), to measure the lifetime prevalence of the most presenting mental disorders in the adult Qatari population, aged 18-65, and examine their symptom patterns and co-morbidity. Design: This is a cross sectional study conducted during the period from April 2010 to October 2011. Setting: Five Primary Health Care (PHC) Centres distributed around the country. Subjects: A total of 1,500 Qatari subjects aged 18 to 65 years were approached; 1,063 (70.8%) gave consent and participated in this study. Methods: Four field supervisors from Qatar were trained and certified as trainers by IDRAAC, the education and training centre responsible for the Arabic translation and validation of CIDI. Variations in Arabic dialect were reported to IDRAAC for verification and approval. In line with the World Health Organization (WHO) World Mental Health (WMH) Survey Initiative, a nationally representative psychiatric epidemiological survey was carried out in Qatar. Prevalence and severity of ICD-10 disorders were assessed with the WHO Composite International Diagnostic Interview (CIDI, Version 3.0). Results: Of the studied 1063 subjects, 50.1% were males and 49.9% were females. Most of the respondents were in the age group 18-34 years (46.1%), followed by 35-49 years (34.1%), then 50-65 years (19.8%). The most common ICD-10 disorders were specific generalized anxiety disorders (20.4)%, and major depression (19.1%), with a higher prevalence in women. 20.6% of the sample had chronic physical conditions. There were high levels of statistically significant differences between age groups and gender regarding Generalized Anxiety Disorders, Social phobia, specific phobia, major depression, and personality disorders screen. Women performed significantly worse as assessed by the 30 day functioning screen (p < 0.001). Conclusion: The findings of this study in lifetime prevalence of mental disorders in Qatar are comparable with international figures. Women were more likely than men to have mental illness. Overall, Generalized Anxiety Disorders; Social phobia, specific phobia, major depression, and personality disorders were the commonest disorders.
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Characterization Of Circular Rnas In Ovarian Cancer
المؤلفون: Ikhlak Ahmed, Thasni K. A. Azis, Eman K. Al-azwani, Yasmin Ali Mohamoud, Arash Rafii and Joel MalekNoncoding RNAs such as ribosomal RNAs (rRNA), transfer RNAs (tRNA) micro RNAs (miRNA), small interfering RNAs (siRNA) and long noncoding RNAs (lncRNA) are the dominant products of eukaryotic transcription and collectively represent more than 95% of total RNA of the cell. In addition to contributing as the core components of the translational machinery (rRNAs and tRNAs), these noncoding RNAs have been shown to be involved in a myriad of biological processes such as gene expression regulation and genome defence. Recently, a novel class of endogenously encoded species of RNA called circular RNAs (circRNA) has been shown to regulate gene expression in mammals by competing with miRNA targets under diverse scenarios. To investigate the role and regulatory potency of circRNAs in ovarian cancer, we performed paired-end RNA sequencing of 9 ovarian cancer samples from three patients at primary and metastatic stages and developed an in-house computational pipeline to identify and characterize the circRNA candidates. Our results show that circRNAs are widely expressed in ovarian cancer and oncogenic factors in cancer-associated pathways are particularly enriched for circRNAs. We also show that isoform diversity of circRNAs is comparable to that of the linear counterparts and a significant fraction of exons are preferentially expressed as circular forms compared to the canonical linear RNA form. Further, these candidate circRNAs are particularly enriched for miRNA seed matches and the hybridization energies of interaction favourably predicts formation of stable structural dimers between circRNAs and miRNA mature sequences. A large number of candidate circRNAs are also differentially expressed between primary and metastatic stages of ovarian cancer and show co-expression with their gene targets, implying a role for circRNAs in regulating expression of oncogenic factors. Taken together this study adds an important new dimension to the role of miRNAs vis-à-vis circRNAs in fine-tuning of gene expression and disease progression in ovarian cancer.
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Hospital 7 Days Working. Recommendations And Feasibility
المؤلفون: Rozh Jalil, Andrew Brodie and Jeetesh BhardwaHospital 7 days working. Recommendations and feasibility Introduction: There is increasing evidence that mortality rates for patients admitted to hospitals are higher at weekends. Furthermore, there is evidence that five-day working costs lives. Increased mortality rates over weekends equate to an increased risk of dying of 11% for a patient presenting on a Saturday and a similar rise of 16% for a Sunday when compared to patients presenting Monday to Friday. One reason suggested for this increased mortality rate is the lack of senior doctor cover and the decreased availability of services over the weekend. During the weekend, on average, only 10-15% of consultants are present in the hospital, even though the weekend comprises 30% of the week. There is also data that shows that the risk of death from an elective procedure is 1.4 times higher if the operation is done on a Friday and 1.8 times higher for a Saturday. We review Sir Bruce Keoh's report -NHS medical Director of the UK by focusing on the feasibility and the impact on health services by putting patient in the centre of care. Methods: The Keoh report was published in November 2013 after concerns have been raised about the discrepancy in mortality and morbidity between weekday and weekends. Levels of service has been categorised into 4 levels as shown in the table 1 Most Hospitals currently are at the level 2-3. Results: In order to implement this change into the health care, 10 standards have been recommended (table 2). The local and national incentives are estimated to be over a 3 year period as follows: Year 1 - local contracts will include an Action Plan to deliver the clinical standards within the Service Year 2 - Clinical standards with the greatest impact will be incorporated into the NHS Standard Contract. Year 3 - all clinical standards will be incorporated nationally into the NHS Standard Contract with sanctions in place for non-compliance. Conclusion: With the implementation of this 7 days working model, morbidity and mortality for the weekends is estimated to decrease to the weekday level, resulting in an overall reduction in total mortality and morbidity rates over the whole week. Furthermore, the inappropriate admissions caused by the decreased availability of weekend senior decision making will diminish, in turn, reducing the costs incurred by unnecessary and protracted hospital stays and additional use of health services. Nevertheless one should consider the constrains of such services (table 3) These recommendations are set for the National Health services of the UK and perhaps could be adjusted as per country, locality and patient needs.
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Apolipoprotein E Gene Polymorphism And The Risk Of Left Ventricular Dysfunction Among Egyptian Β-thalassemia Major.
المؤلفون: Mona El-tagui, Mona Hamdy, Iman Shaheen, Hoda Agha and Hoda Abd-elfatahIn Egypt, β-thalassemia is the most common hereditary hemolytic anemia. Cardiac dysfunction, secondary to iron overload with formation of oxygen free radicals, is the most common cause of death in β-thalassemia patients. This study was designed to determine whether the allelic genotype of apolipoprotein E (Apo E), which exhibits antioxidant properties, could represent a genetic risk factor for the development of left ventricular (LV) dysfunction in β-thalassemia major. Fifty Egyptian β-thalassemia major patients were subjected to echocardiography to assess LV function. Apo E genotyping by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) was done for all patients in addition to 50 age and sex matched healthy control subjects. Patients were classified into three groups. Group I and II were clinically asymptomatic. Group II subjects had evidence of LV dilatation, while Group III patients had clinical and echocardiographic findings of LV failure. Apo E4 allele was significantly higher among Group II and III than in controls. In conclusion, Apo E4 allele can be considered as a genetic risk factor for LV dysfunctions in β-thalassemic patients. It could be used as predictive indicator for additional risk of LV failure, particularly in asymptomatic patients with LV dilatation, requiring a closer follow-up, to prevent further disease progression
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A Comprehensive Approach To The Prediction Of Acute Calcular Cholangitis - The Qatar Experience
المؤلفون: Hisham Allam, Mohammed Al Dosouky, Abdulaziz Farooq, Ahmed Naggar and Adarsh VijayIntroduction: The aim of the present study is to identify clinical, laboratory and radiological factors that can predict which patients may develop cholangitis. Methods: This is a retrospective case-control study based on patients admitted to Hamad Hospital from June'06 to November'10 with a diagnosis of AC secondary to CBD stones. The control group included patients with obstructive lithiasic jaundice not complicated by cholangitis. Both groups were compared and analysed with respect to demographics, previous medical/surgical history, laboratory investigations and surgical/endoscopic procedures. Results: The study comprised of 112 patients of 24 different nationalities. 53 patients presented with AC and 59 were admitted for management of obstructive jaundice. Although Asians had a greater prevalence of cholangitis (57.4%) compared to Middle Easterners (35.7%) and Africans (33.3%), this was not statistically significant (P=0.066). Laboratory tests significantly correlated to AC were leukocytosis (P<0.001), elevated Bilirubin (P=0.005), prolonged prothrombin time (P=0.001), elevated INR (P=0.001), elevated serum Creatinine (P=0.001) and BUN (P=0.001). In univariate analysis the logistic regression model showed that dark urine, fever, elevated WBC and BUN were strongly associated with cholangitis. Conclusions: Typical clinical signs of acute cholangitis, history of chronic liver disease, together with certain biochemical criteria are strongly associated with occurrence of acute lithiasic cholangitis. A larger prospective study may probably confirm these findings and help create a reproducible and simple predictive scoring system.
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Environment Gene Interaction In Parkinson's Disease (egi-pd).
المؤلفون: Mohamed Salama, Thomas Rösler, Ali Shalash, Abdelhaleem Tantawy and Günter HöglingerEnvironment Gene Interaction in Parkinson's disease (EGI-PD) Mohamed M. Salama1, Thomas W. Rösler2, Ali Shalash3, Abdelhaleem Tantawy4, , Günter U. Höglinger2,5 1Toxicology Department, Faculty of Medicine, Mansoura University, Mansoura, Egypt 2Department for Translational Neurodegeneration, German Center for Neurodegenerative Diseases (DZNE), Munich, Germany 3. Department of Neurology, Faculty of Medicine, Ain Shams University, Cairo, Egypt 4. Department of Neurology, Faculty of Medicine, Mansoura University, Mansoura, Egypt 3 Department of Neurology, Technical University, Munich, Germany Introduction: The prevalence of PD is increased in Egypt compared to reports in other countries. Both genetic and environmental causes might be responsible. E.g. a high rate of LRRK2 mutations has been reported in other North African countries, but has not been systematically studied in Egypt. Also, several epidemiologic studies have supported the hypothesis that broadly defined pesticide exposure may increase the risk of PD. A high degree of pesticide use occurs in Egypt due to the limited availability of agricultural areas in the country. Moreover, lack of precautionary measures on applying pesticides leads to increased pesticide exposures. We aimed to study the link between genes encoding detoxifying enzymes and PD-risk genes on one hand and exposure to pesticides on the other hand in the etiology of PD in Egypt. Methods: This work is undertaken in collaboration between the Technische Universtität München, Germany and a network of 16 Egyptian Universities leaded by Mansoura University (Egyptian Network of Neurodegenerative Diseases [ENND]). PD cases from all over Egypt are recruited. Half of the cases were chosen in areas of low pesticide exposure, the other half with high pesticides exposure (farmers 50 years of age or older). Similar numbers of non-PD controls are chosen from two sources; first, patients arriving to outpatient clinic who are not suffering from any other neurodegenerative disorder; secondly, persons accompanying participating PD patients. Controls are further stratified into low pesticides and high pesticides controls, as described for the PD cases. Patients are assessed with a standardized questionnaire to evaluate past exposure to pesticides or other Parkinson-related environmental factors, a standardized clinical neurological examination to verify presence of PD (UK brain bank criteria) and to quantify disease severity (Hoehn & Yahr stage, UPDRS motor part) and genotyping for presence or absence of risk-carrying alleles in detoxification and Parkinson's associated genes. Results: We were able to establish ENND which is the first collaborative network of this type in Egypt. Moreover, we established a functional Standard Operation Procedure to collect and ship clinical data and blood for analysis to the German cooperation partner at TUM. So far, we collected blood and epidemiological data from 70 cases and 80 controls. Preliminary data on the analysis of gene-environment interaction analysis will be presented. Conclusion: This work will provide further insights into the mechanisms of gene environment interplay in the etiology of PD and hopefully insights which allow the establishment of primary preventive measures. Funding: DAAD-funded Al-Tawasul project EGI-PD
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Overexpression Of Human S100a4 Gene In Drosophila Melanogaster Can Promote Metastasis
مزيد أقلThe major problem with cancer is the ability of cancer cells to infiltrate surrounding tissue (invasion) or to spread to distant organs (metastasis), decreasing patient survival. One of the Ca2+ binding proteins of the S100 family, S100A4, is expressed at elevated level in several forms of cancer and has the ability to induce metastasis and invasion in benign mammary cells. In order to generate a genetically tractable experimental model of S100A4-mediated metastasis, we have expressed the human S100A4 in the fruit fly Drosophila melanogaster to uncover players in tumour progression, invasion and metastasis. Here we demonstrate that the expression of full open reading frame of human S100A4 wild type protein in cooperation with RasVal12 into Drosophila, developed metastatic phenotypes. Fly larvae expressing the human S100A4 as determined by Western blot exhibit metastasis in the ventral nerve cord when crossed with Drosophila strains expressing oncogenic RasVal12 targeted to the optic lobes by the UAS-GAL4 system. However, the mutant of S100A4 (S100A4/∆2) missing the last two lysine reduced the tumour dissemination into the ventral nerve cord in Drosophila flies expressing RasVal12 oncogene. Downstream genes associated with the metastatic behaviour including JNK and MMPs (metalloproteinase) proteins are also investigated. We showed that the MMPs and the JNK are also activated in the flies with S100A4/ RasVal12 genotype. Loss this activation in flies with S100A4∆2/RasVal12 genotype indicated that MMPs and JNK proteins are essential in tumour progression and metastasis pathways. Therefore, MMPs and JNK are excellent targets for cancer therapy.
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Inhaled Magnesium For Moderate And Severe Pediatric Asthma
Objective: We hypothesized that nebulized magnesium sulfate added to combined bronchodilator and systemic steroid therapy would shorten time to discharge without undue risk. Study design: Patients aged 2 to 14 y with moderate and severe asthma (PRAM severity score >4) admitted to infirmary care were randomized double-blind to 800 mg nebulized isotonic magnesium sulfate or normal saline placebo via Aeroneb Pro and Idehaler, after intensive therapy with combined albuterol-ipratropium and intravenous methylprednisolone. Time to medical readiness for discharge was the primary outcome. Improvement over time in PRAM severity score and other secondary outcomes were compared for the overall group and severe asthma subset. Results: 191 magnesium sulfate and 174 placebo patients met criteria for analysis. The groups were similar with mean baseline PRAM scores>7. Blinded active therapy significantly increased blood magnesium level 2 h post-treatment 0.85 (SD 0.07) vs 0.82 (SD 0.06) mmol/L, p=0.001). There were no important adverse effects. Accelerated failure time analysis showed a non-significantly relatively shortened time to medical readiness for discharge of 14% favoring the magnesium sulfate group, OR=1.14, 95% CI 0.93 to 1.40, p=0.20, with an absolute prolonged time at 24 h of 2.1 h, p=0.5 . Mean times until readiness for discharge were 14.6 h [SD 9.7] vs 15.6 h [SD 11.3] for the investigational and placebo groups, respectively, p=0.9. Conclusions: Adding nebulized magnesium sulfate to combined nebulized bronchodilator and systemic steroid therapy is either very weakly or very rarely effective, or futile for benefitting pediatric patients with moderate or severe asthma.
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Application Of Bioluminescence, Cyto And Genotoxicity To Measure The Efficacy Of Oregano Oil As An Antimicrobial Agent
المؤلفون: Nahla Omer Eltai, Vyv Salisbury and John GreenmanObjectives To develop and validate a new technique for hand hygiene for use in healthcare settings; to evaluate correlation between bioluminescence and conventional time consuming viable counting methods; to use bioluminescent constructs of bacterial pathogens as a real time biosensors for rapid bactericidal monitoring and to conduct in vitro toxicity tests of the Himalayan oregano oil (HOO) against human cell lines. The ultimate aim of this study is to improve the quality of care of patients through application of a new hand hygiene which could be more acceptable to users while maintaining the efficacy of current hand hygiene disinfectant. Methods: Representatives of the common UK bacterial pathogens Escherichia coli, Pseudomonas aeruginosa and Methicillin sensitive Staphylococcus aureus were used in experiments. Strains used had been previously genetically modified with addition of lux CDABE operon to express bioluminescence in order that they could be used as reporter of viable metabolically active cells to show a real time in situ antimicrobial effect of HOO. Oregano oil samples were analysed for the percentage contents of thymol and carvacrol using gas chromatography. Potential toxicity of Oregano oil at a range of concentrations on cultured human keratinocytes and Jurkat cells were determined using Neutral Red, WST and MTS assays. Results: High correlation was obtained between viable count and bioluminescence. Application of HOO in concentrations effective against bacteria was found to be safe to human keratinocytes (fig.1 and 2) Conclusions: Bioluminescence has the capability to replace the plate culture method for evaluating the efficacy of a new antimicrobial product as it provides a rapid means of collecting data on the antimicrobial action of HOO. HOO may have the potential as a natural potent antimicrobial agent in the health care setting, as it has demonstrated biocidal action towards significant pathogens in a short time. Application of the oil in the correct dilution was found to be safe on human keratinocytes.
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Insulin Resistance-associated Impairment Of Preadipocyte Differentiation In Human Abdominal Obesity
OBJECTIVE: Differentiation capacity of human preadipocytes exhibits depot specific variation and is influenced by local cytokine production. The effect of obesity-induced insulin resistance on preadipocyte differentiation and its relation to proinflammatory cytokine release was investigated. RESEARCH DESIGN AND METHODS: Differentiation of preadipocytes obtained from subcutaneous & omental tissue biopsies isolated from obese patients undergoing weight reduction surgery and their cytokines release were compared between insulin sensitive and insulin resistant subjects. RESULTS: Compared to subcutaneous-derived cells, omental cells expanded from the same patients showed diminished differentiation, marked by increased proinflammatory cytokines secretion. When subjects were dichotomized into insulin sensitive & insulin resistant depending on their HOMA-IR, preadipocytes derived from insulin sensitive subjects exhibited a greater ability to differentiate into larger adipocytes with more lipid droplets, marked by a lower expression and secretion of IL-6 and TNFα. Addition of these cytokines inhibited preadipocyte differentiation in insulin sensitive-derived cultures, suggesting that proinflammatory cytokines may underlie inhibition of differentiation seen in insulin resistant patients-derived cultures. CONCLUSIONS: These findings suggest that insulin-resistance is associated with impaired preadipocyte differentiation and increased proinflammatory cytokines release. Understanding mechanisms underlying impaired preadipocyte differentiation associated with insulin resistance may help future treatment strategies.
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Map Kinase Phosphatase Dusp1 Is Overexpressed In Human Obese And Modulated By Physical Exercise
Chronic low-grade inflammation and uncontrolled metabolic stress response are cardinal features of obesity; a major risk factor for the development diabetes. Dual specificity protein phosphatase 1 (DUSP1) is implicated in metabolism and energy expenditure. Mice lacking DUSP1 are resistant to high fat diet-induced obesity. However, the expression of DUSP1 has not been investigated in human obesity. In the current study, we compared the expression pattern of DUSP1 between lean and obese non-diabetic human subjects using subcutaneous adipose tissue and peripheral blood mononuclear cells. The levels of DUSP1 mRNA and protein were significantly increased in obese subjects with concomitant decrease in the phosphorylation of p38 MAPK and PGC-1α and an increase in the levels of phospho-JNK and phospho-ERK. Moreover, obese subjects had higher levels of circulating DUSP1 protein that correlated positively with various obesity indicators, triglycerides, glucagon, insulin, leptin and PAI-1 (P<0.05), but negatively with VO2, Max and high-density lipoprotein (P<0.05). The observation that DUSP1 was overexpressed in obese subjects prompted us to investigate if physical exercise could reduce its expression. In this study, we report for the first time that physical exercise significantly attenuated the expression of DUSP1 with a parallel increase in the expression of PGC-1α and a reduction in JNK and ERK activities along with attenuated inflammatory response. Collectively, our data suggest that DUSP1 upregulation is strongly linked to adiposity and physical exercise modulates its expression. This gives further evidence that exercise might be useful as a strategy for managing obesity and preventing its associated complications.
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Effect Of Using Gingival Stem Cells And Therapeutic Ultrasound On Periodontal Ligament During Orthodontic Treatment In Beagle Dogs.
Previous studies have shown that low intensity pulsed ultrasound (LIPUS) can prevent orthodontically induced teeth root resorption (OITRR) in human. Also, stem cells have been used to treat different types of bone defects. Severe OITRR is still untreatable problem in orthodontics. The aim of this study was to evaluate the effect of local injection of osteogenically induced gingival stem cells (OIGSCs) and LIPUS on periodontal ligament (PDL) during tooth movement that induces OITRR in beagle dogs. We hypothesized that local injection of OIGSCs and LIPUS can enhance PDL metabolism and hence enhances the reparative effect of OITRR. Seven adolescent beagle dogs were used and their third and fourth premolars were moved orthodontically. Gingival stem cells were isolated, characterized by flowcytometry and were differentiated into osteoblast -like cells using osteogenic medium to produce osteogenically induced gingival cells (OIGCs). OIGSCs were then re-injected into the alveolar bone in the proximity of the roots of the orthodontically moved teeth. Premolars were randomly divided into five groups. 1) Negative control (OITRR only); 2) Local injection of BMP; 3) OIGSCs; 4) LIPUS and 5) LIPUS +OIGSCs. In LIPUS groups, premolars were treated for four weeks. Animals were then euthanized and tissue blocks were processed for histological and histomorphometric analysis. Cementum thickness, PDL thickness and PDL cell number were counted using Metamorph software. Measurements were made at three levels of the tested roots. Level 1 is the coronal level 9towards the crown); level 2 (middle level of the root) and level 3 (apical, towards the apex of the roots). Variables were compared between groups by Wilcoxon Signed Ranks Test using SPSS statistical package. Results showed that LIPUS, BMP2 and LIPUS+OIGCs significantly increased cementum thickness compared to control group in the apical area of the teeth roots (P<0.05). There was statistically significant increases in PDL thickness and PDL cell count in all groups compared to control group (P<0.05). The combined LIPUS+OIGCs showed the highest cell count between al the groups. Conclusion: LIPUS + OIGCs showed the highest PDL regeneration potential and may be used in clinical cases with severe OITRR.
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