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Amyotrophic lateral sclerosis (ALS), most commonly known as Lou Gehrig's disease, is a progressive neurodegenerative disease that attacks nerve cells in the brain and spinal cord resulting in muscle weakness and atrophy. The ALS A...
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Amyotrophic lateral sclerosis (ALS), most commonly known as Lou Gehrig's disease, is a progressive neurodegenerative disease that attacks nerve cells in the brain and spinal cord resulting in muscle weakness and atrophy. The ALS Association's national Web site provides comprehensive information on a wide variety of topics pertinent to ALS patients, caregivers, family members, and health care professionals. This well-organized, easy-to-navigate site is an excellent resource for anyone seeking to learn about ALS.
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Exchangeable aluminium (Al_(KCI)) and CaCl_2-extractable aluminium (Al_(CaCl_2) approximately the same value in the prognosis of detrimental effect on plants. Additional, more in-depth research should show which of the two applied...
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Exchangeable aluminium (Al_(KCI)) and CaCl_2-extractable aluminium (Al_(CaCl_2) approximately the same value in the prognosis of detrimental effect on plants. Additional, more in-depth research should show which of the two applied methods of exchangeable
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Using the phase-field crystal method, we investigated the bcc {1 1 0} vicinal surface growth from melts at the atomic scale with emphasis on the growth kinetics of two growth modes: step flow growth and island growth on terrace. S...
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Using the phase-field crystal method, we investigated the bcc {1 1 0} vicinal surface growth from melts at the atomic scale with emphasis on the growth kinetics of two growth modes: step flow growth and island growth on terrace. Simulation results show that, for step flow growth, with the decrease of terrace width, the competition for feeding atoms between neighboring steps causes growth rate vs. step density to deviate from a linear relationship, and finally converge to a finite value. The step crystal direction also strongly influences the growth kinetics: vicinal surface with steps along the closest packed direction— [111] grows slower than that with [001] step. For island growth on terrace, the growth exponent of each layer in multi-layer island gradually transits from 1/2 for the top layer to 1/3 for the bottom layer, which demonstrates the transition from global diffusion controlled growth for top layer to surface diffusion controlled growth for bottom layer. The growth mechanism selection map with respect to terrace width and supersaturation is summarized and atom attaching rates of different growth mechanisms are also compared.
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Представлены результаты исследований методом теории функционала плотности (DFT) стыковки по грани (111) блоков (первичных наноча...
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Представлены результаты исследований методом теории функционала плотности (DFT) стыковки по грани (111) блоков (первичных наночастиц) низкотемпературных метастабильных оксидов алюминия (η-Al2O3 и χ-Al2O3). Рассчитана удельная поверхностная энергия грани (111) кристалла Al2O3, рассмотрено прохождение доменной границы через различные катионные слои, определены константы ядерного квадрупольного взаимодействия для ядер 27Аl.
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The paper proposes a new theoretical model based on local thermodynamic equilibrium enabling the prediction of gas generation during the reaction of aluminum-based thermites. We demonstrate that the model has the capability to pre...
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The paper proposes a new theoretical model based on local thermodynamic equilibrium enabling the prediction of gas generation during the reaction of aluminum-based thermites. We demonstrate that the model has the capability to predict the total pressure and the partial pressures of its components as a function of the reaction extent and compaction. Al/CuO, Al/Bi2O3, Al/Sb2O3, Al/MoO3, and Al/WO3 thermites are modeled and their capability to generate pressure is compared. Simulation results are also validated through dedicated experiments and show general agreement beyond the state of the art. Mechanisms underlying pressure generation are detailed. A two-stage process for the pressure increase in Al/CuO reaction, also observed experimentally, is shown to be driven by oxygen generation as produced by CuO and Cu2O vaporization through different kinetics. Comparison with experimental data stresses the issue of understanding the complex chemical processes taking place during vaporization and subsequent gas phase reactions and the need to determine their thermodynamic constants.
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We study the motion of a planar thermal wave, which is simultaneously a phase boundary in a thin cooled film, driven by the application of an electrical current and Joule heating. Based on theoretical modeling by Brener and Temkin...
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We study the motion of a planar thermal wave, which is simultaneously a phase boundary in a thin cooled film, driven by the application of an electrical current and Joule heating. Based on theoretical modeling by Brener and Temkin (1996) [1] we employ a phase field model that reproduces the analytical predictions for planar front propagation and interface stability. Three-dimensional simulations of the growth of a filament advancing from one electrode to the other demonstrate the applicability of the model towards more complex geometries and problems originating from the microstructure formation in phase change materials.
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The contamination of drinking and irrigation water by arsenic is a severe health risk to millions of people, particularly in developing countries. Arsenic treatment methods therefore need to advance to more durable and cost-effect...
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The contamination of drinking and irrigation water by arsenic is a severe health risk to millions of people, particularly in developing countries. Arsenic treatment methods therefore need to advance to more durable and cost-effective solutions. In recent years, the unique properties of nanomaterials have received much attention in water treatment research, and their properties (e.g., high number of reactive surface binding sites) may make them suitable for arsenic removal. The aluminum nanoclusters Al13 (AlO4Al12(OH)24H2O12 7+) and Al30 (Al2O8Al28(OH)56(H2O)26 18+) have high specific surface charge, deprotonate over a wide pH range and exhibit a high reactivity due to a great number of OH− and H2O groups. This contribution evaluates these chemical properties of aluminum nanoclusters and their efficiency for water treatment, particularly for arsenic removal. It assesses the advantages and constraints when applied in an industrially produced aluminum coagulant or in Al granulate during water treatment.
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The mobility of aluminium in sediments was evaluated through a one-step extraction with a strong chelating agent. Single and sequential extraction procedures for the extraction of Al were applied to four sediments from a polluted ...
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The mobility of aluminium in sediments was evaluated through a one-step extraction with a strong chelating agent. Single and sequential extraction procedures for the extraction of Al were applied to four sediments from a polluted region. A single-step extraction with 0.05 mol L~(-1) ethylenediaminetetraacetic acid (EDTA) was used, and compared with a standardized SEP as reference. The Al contents extracted into Na2EDTA were in good agreement with the sequential extraction that yeilds mobile and potentially mobile portion of Al. Extracted EDTA contents make up more than 70% of the first-three-step sum of the five-step extraction procedure. Thus, Na2EDTA extraction of Al could be applied to assess aluminium mobility changes in sediments and soils.
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Populations of water starwort, a winter annual or biennial weed in the pink family (Caryophyllaceae), can no longer be controlled by tribenuron following successive use of this herbicide over several years. Whole-plant bioassays h...
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Populations of water starwort, a winter annual or biennial weed in the pink family (Caryophyllaceae), can no longer be controlled by tribenuron following successive use of this herbicide over several years. Whole-plant bioassays have established that the resistant water starwort populations JS17, JS08, JS16, and JS07 showed high-level (from 203-fold to 565-fold) resistance to tribenuron. In vitro acetolactate synthase (ALS) assays revealed that resistance was due to reduced sensitivity of the ALS enzyme to tribenuron. The half-maximal inhibitory concentration (I50) values for JS17, JS08, JS16, and JS07 were 72, 71, 70, and 76 times greater, respectively, than were those of the susceptible population JS24. This altered ALS sensitivity in the resistant populations was due to a mutation in the ALS gene resulting in a Pro197 to Ser substitution (JS17, JS08, and JS16) and a Pro197 to Leu substitution (JS07). This study established the first documented case, to our knowledge, of evolved tribenuron resistance in water starwort and concluded that the molecular basis of resistance is due, at least in part, to a target-site modification at Pro197 in the ALS gene.
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The silicon core and carbon mantle particles were produced by using the advanced carbon coating method which enables direct covering with the carbon layer using an electron microscope. The growth of SiC crystal was observed upon h...
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The silicon core and carbon mantle particles were produced by using the advanced carbon coating method which enables direct covering with the carbon layer using an electron microscope. The growth of SiC crystal was observed upon heating at 500℃ in vacuum. The growth process of SiC on both the carbon layer and silicon particles was directly observed by in situ observation. The inward movement of carbon into silicon began at the twinned part. The growth rate of SiC on the carbon mantle layer was estimated from in situ images and found to be 8 times faster than the growth rate of silicon carbide in silicon particles.
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