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Particuology 2019年第5期17卷 22-29页

作者： m. Hafizur rahman Lius Daniel Ujash Shah Xiaotao Bi john r. Grace C.Jim Lim Fluidization research Centre Department of Chemical & Biological Engineering University of British Columbia 2360 East Mall Vancouver British Columbia V6T1Z3 Canada

Operation of a dual fluidized bed, consisting of a riser as combustor and bubbling bed as gasifier, for synthesis gas production from a solid fuel requires determination of the solids circulation rate and char transfer rate. The performance relies on supplying sufficient heat from the combustor to the gasifier by circulation of solids between these two reactors. The flow rate of char is required to track the heat generated in the combustor, which supports endothermic reactions in the gasifier. Direct measurement of these two critical parameters is difficult, with the number of reported techniques capable of working at high temperatures extremely small. An indirect method was developed, using mass and energy balances over the entire system and individual reactors, to estimate the solids circulation rate and char transfer rate. There was general agreement between heat losses estimated from energy-balance calculations and from direct measurement of the outer reactor surface temperature. Under typical gasification conditions, the solids circulation fluxes were estimated to be 45.2 and 55.6 kg/(m^2 s) in two independent tests, which were in good agreement with values obtained using a thermal tracer;char transfer rates were calculated to be 1.2 and 0.6 kg/h, which were in reasonable agreement with average biomass feed rates. This method can be applied to dual gasification systems at any temperature or flow rate.

关键词： Solids circulation rate Char transfer rate Pilot-plant gasifier Dual fluidized bed mass and energy balance

Functionalized, carbon nanotube material for the catalytic degradation of organophosphate nerve agents

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Nano research 2014年第3期7卷 390-398页

作者： mark m. bailey john m. Heddleston Jeffrey Davis Jessica L. Staymates Angela r. Hight Walker National Institute of Standards and Technology (NIST) Semiconductor and Dimensional Metrology Division Gaithersburg MD USA National Institute of Standards and Technology (NIST) Materials Measurement Science Division Gaithersburg MD USA Present Address: United States Army medical research Institute of Infectious Diseases (USAmrIID) Center for Aerobiological Sciences Fort Detrick MD USA

recent world events have emphasized the need to develop innovative, functional materials that will safely neutralize chemical warfare （CW） agents in situ to protect military personnel and civilians from dermal exposure. Here, we demonstrate the efficacy of a novel, proof-of-concept design for a Cu-containing catalyst, chemically bonded to a single-wall carbon nanotube （SWCNT） structural support, to effectively degrade an organophosphate simulant. SWCNTs have high tensile strength and are flexible and light-weight, which make them a desirable structural component for unique, fabric-like materials. This study aims to develop a self-decontaminating, carbon nanotube-derived material that can ultimately be incorporated into a wearable fabric or protective material to minimize dermal exposure to organophosphate nerve agents and to prevent accidental exposure during decontamination procedures. Carboxylated SWCNTs were functionalized with a polymer, which contained Cu-chelating bipyridine groups, and their catalytic activity against an organophosphate simulant was measured over time. The catalytically active, functionalized nanomaterial was characterized using X-ray fluorescence and raman spectroscopy. Assuming zeroth-order reaction kinetics, the hydrolysis rate of the organophosphate simulant, as monitored by UV-vis absorption in the presence of the catalytically active nanomaterial, was 63 times faster than the uncatalyzed hydrolysis rate for a sample containing only carboxylated SWCNTs or a control sample containing no added nanotube materials.

关键词： single-wall carbonnanotubefunctionalization catalytically-activenanomaterial chemical warfare agent

resolution of acute gastroenteritis symptoms in children and adults treated with a novel polyphenol-based prebiotic

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World Journal of Gastroenterology 2014年第34期20卷 12301-12307页

作者： Telma Noguera robert Wotring Chris r melville Kara Hargraves Jochen Kumm john m morton Instituto Centroamericano de Investigación Clínica Managua 050-008-4Nicaragua Greenteaspoon Inc StanfordCA 94305United States Department of Biology Stanford UniversityStanfordCA 94305United States bariatric and minimally Invasive Surgery Stanford School of MedicineStanfordCA 94305United States

AIm: To test efficacy and durability of a polyphenol-based prebiotic treatment for acute gastroenteritis in a 300 patient double-blinded clinical study.

关键词： Prebiotic Gastroenteritis Diarrhea rotavirus Infant mortality Dehydration Heartburn Polyphenol Aliva Greenteaspoon

Nanoengineering of Flux Pinning Sites in High-T_c Superconductors

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Tsinghua Science and Technology 2003年第3期8卷 280-291页

作者： m.r.Koblischka Institute of Experimental Physics University of SaarbryckenP.O.Box 15 11 50D-66041 SaarbruckenGermany

Volume pinning forces were determined for a variety of bulk high-Tc superconductors of the 123-type from magnetization measurements. By means of scaling of the pinning forces, the acting pinning mechanisms in various temperature ranges were identified. The Nd-based superconductors and some YBCO crystals exhibited a dominating pinning of the δTc-type (i.e. , small, superconducting pinning sites). In contrast to this, the addition of insulating 211 particles provided pinning of the δ/-type; providing effective pinning in the entire temperature range acting as a 'background' pinning mechanism for the peak effect. Due to the small coherence lengths of the high-Tc compounds, effective pinning sites are defects or particles of nanometer size relative to ζ3. Integral magnetic measurements of the magnetization as a function of temperature in large applied magnetic fields (up to 7 T) revealed that practically all high-Tc compounds were spatially inhomogeneous, which could be caused by oxygen deficiency (YBCO), solid solutions of Nd/ba (NdBCO and other light rare earth compounds), intergrowths (Bi-based superconductors), and doping by pair-breaking dopants like Zn, Pr. This implies that the superconducting sample consists of stronger and weaker superconducting areas, coupled together. In large applied fields, this coupling gets broken and the magnetization versus temperature curves revealed more than one superconducting transition. In contrast, irradiation experiments by neutrons, protons, and heavy-ions enabled the artificial introduction of very effective pinning sites into the high-Tc superconductors, thus creating a large variety of different observations using magnetic data. From all these observations, we construct a pinning diagram for bulk high-Tc superconductors explaining many features observed in high-Tc samples.

关键词： flux pinning critical current densities peak effect spatial variations of the transition temperature nanoengineering of pinning sites

Tribo-charging of binary mixtures composed of coarse and fine particles in gas-solid pipe flow

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Particuology 2019年第2期17卷 101-109页

作者： Haifeng Wang Farzam Fotovat Xiaotao T. Bi john r. Grace Department of Chemical Engineering China University of Mining and Technology. Xuzliou 221166 China Department of Chemical and Petroleum Engineering Sharif University of Technology Azadi Avenue P.O. Box 11365-9465 Tehran Iran Fluidization research Centre Department of Chemical and Biological Engineering University of British Columbia. Vancouver V6T 1Z3 Canada

Experiments were conducted to investigate the effect of adding fines on the tribo-charging of coarse glass beads. Four types of fines, i.e., copper, stainless steel, uncoated and silver-coated fine glass beads, mixed w让h 240-830 μm glass beads were conveyed by air through a stainless-steel spiral pipe acting as a tribo-charger. regardless of the type or electrical conductivity of the fine particles tested, adding small amounts of fines (up to 10wt%) to coarse glass beads resulted in a sharp increase in the mass and surface charge densities of the particles. In gen eral, the profiles of the mass and surface charge den sides of the fine-coarse particle mixtures as a function of the mixture composition were determined by the relative magnitude of contact potential differences and the total surface areas of all the comp on ents. The domi nant particle tri bo-electrification mecha nism switched from coarse particle-wall con tacts to fine particle-wall contacts when the fines weight percentage in the mixture exceeded 10%. A model was developed to predict the mass charge density of bi nary mixtures as a function of the mixture composition.

关键词： Tribo-charging Electrostatics Fine particles Binary mixture Gas-solid flow

Influence of Lanthanum on the microstructural and Dielectric Properties of Polycrystalline ba(Ti0.5Fe0.5)O3

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Chinese Physics Letters 2012年第4期29卷 213-216页

作者： m.r.Shah A.K.m.Akther Hossain Department of Physics Primeasia UniversityBananiDhaka-1213Bangladesh Department of Physics Bangladesh University of Engineering and TechnologyDhaka-1000Bangladesh

Various polycrystalline ba1-x Lax (Ti0.5 Fe0.5 )O3 are prepared by using the standard solid state reaction *** shaped samples prepared from each composition are sintered at 1200℃ for 5 h.X-ray diffraction patterns of these compositions confirm the formation of a single phase perovskite *** lattice parameters are decreased but the average grain size increases with the increase of La *** dielectric constant,dielectric loss and ac conductivity are studied as a function of frequency for various compositions,and their behaviors are explained on the basis of the maxwell-Wagner model A three-times enhancement of the dielectric constant is observed with the increase of La content.

关键词： Ti structure technique

Advantages of using the CrISPr/Cas9 system of genome editing to investigate male reproductive mechanisms using mouse models

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Asian Journal of Andrology 2015年第4期17卷 623-627页

作者： Samantha Am Young r john Aitken masahito Ikawa Priority research Centre in reproductive Science Discipline of Biological Sciences Faculty of Scienceand IT University of Newcastle Callaghan NSWAustralia Animal resource Centre for InfectiousDiseases Research Institute for Microbial DiseasesOsaka University Suita Osaka Japan.Correspondence: Prof. M Ikawa

Gene disruption technology has long been beneficial for the study of male reproductive biology. However, because of the time and cost involved, this technology was not a viable method except in specialist laboratories. The advent of the CrISPr/Cas9 system ofgene disruption has ushered in a new era of genetic investigation. Now, it is possible to generate gene-disrupted mouse models in very tittle time and at very little cost. 1his Highlight article discusses the application of this technology to study the genetics of male fertility and looks at some of the future uses of this system that could be used to reveal the essential and nonessential genetic components of male reproductive mechanisms.

关键词： Advantages investigate mechanisms

Provenance and depositional setting of the Late miocenePleistocene clastic sediments in the eastern Arabian Peninsula and western Iraq using rare earth elements geochemistry

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Acta Geochimica 2024年第2期43卷 399-410页

作者： Salih m.Awadh Zinah S.Al-Ankaz mohanad r.A.Al-Owaidi john S.Armstrong-Altrin Department of Geology College of ScienceUniversity of BaghdadBaghdadIraq Department of Geology College of ScienceUniversity of WasitWasit 52011Iraq Department of Applied Geology College of ScienceUniversity of BabylonBabylon 51001Iraq Unidad de Procesos Oceanicos y Costeros Instituto de Ciencias del Mar y LimnologíaUniversidad Nacional Autonoma de MexicoCiudad Universitaria04510 Mexico CityCDMXMexico Department of marine Sciences Bharathidasan UniversityTiruchirapalliTamil Nadu 620024India

The sandstones of the Late miocene–Pliocene Dibdibba Formation in the Najaf–Karbala Plateau and basra were examined to determine their source rocks and origin. The rare earth elements(rEE) and trace elements(Sc, Co, V, and Th) concentrations in these sandstones revealed that they likely derived from a single source. The steep light rare earth elements(LrEE) and flat, heavy rare earth element(HrEE) patterns, negative Eu anomaly, and high ΣrEE contents in sandstones suggest its derivation from a suggests that a passive continental margin environment and originated from felsic source rocks. The average concentration of ΣrEE is 93.5 ppm, which is lower than that of the average crustal compositions like Upper Continental Crust and Post Archean Australian Shale. The higher proportion of LrEE compared to HrEE implies that these sandstones were recycled and derived from a distal source. The Th/Co, Th/Sc, La/Sc, La/Co, Eu/Eu*and(La/Lu)cn elemental ratios indicated that these Late miocene–Pliocene sandstones were derived from felsic rocks located in the marginal region of the Arabian Shield.

关键词： rEE Dibdibba formation Clastic sediments Passive continental margin

Targeted proteomics for biomarker discovery and validation of hepatocellular carcinoma in hepatitis C infected patients

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World Journal of Hepatology 2015年第10期7卷 1312-1324页

作者： Gul m mustafa Denner Larry john r Petersen Cornelis J Elferink Department of Pharmacology and Toxicology University of Texas Medical Branch Department of Internal medicine University of Texas Medical Branch Department of Pathology School of medicine University of Texas Medical Branch

Hepatocellular carcinoma(HCC)-related mortality is high because early detection modalities are hampered by inaccuracy,expense and inherent procedural *** there is an urgent need for minimally invasive,highly specific and sensitive biomarkers that enable earlydisease detection when therapeutic intervention remains practical. Successful therapeutic intervention is predicated on the ability to detect the cancer early. Similar unmet medical needs abound in most fields of medicine and require novel methodological approaches. Proteomic profiling of body fluids presents a sensitive diagnostic tool for early cancer detection. Here we describe such a strategy of comparative proteomics to identify potential serum-based biomarkers to distinguish high-risk chronic hepatitis C virus infected patients from HCC patients. In order to compensate for the extraordinary dynamic range in serum proteins,enrichment methods that compress the dynamic range without surrendering proteome complexity can help minimize the problems associated with many depletion methods. The enriched serum can be resolved using 2D-difference in-gel electrophoresis and the spots showing statistically significant changes selected for identification by liquid chromatographytandem mass spectrometry. Subsequent quantitative verification and validation of these candidate biomarkers represent an obligatory and rate-limiting process that is greatly enabled by selected reaction monitoring(Srm). Srm is a tandem mass spectrometry method suitable for identification and quantitation of target peptides within complex mixtures independent on peptidespecific antibodies. Ultimately,multiplexed Srm and dynamic multiple reaction monitoring can be utilized for the simultaneous analysis of a biomarker panel derived from support vector machine learning approaches,which allows monitoring a specific disease state such as early HCC. Overall,this approach yields high probability biomarkers for clinical validation in large patient

关键词： Hepatocellular carcinoma Biomarkers Early detection Selected reaction monitoring Targetedproteomics

Hydrolysis of filter-paper cellulose to glucose by two recombinant endogenous glycosyl hydrolases of Coptotermes formosanus

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Insect Science 2010年第3期17卷 245-252页

作者： Dunhua Zhang Alan r. Lax john m. Bland Jiujiang Yu Natalie Fedorova William C. Nierman Formosan Subterranean Termite research Unit Southern Regional Research Center ARS USDA New Orleans Food & Feed Safety research Unit Southern Regional Research Center ARS USDA New Orleans Department of Biochemistry and molecular Biology The George Washington University School of Medicine Washington DC The J. Craig Venter Institute Rockville MD USA

Genes encoding for glycosyl hydrolases （GH） in multiple families were recovered from an expression sequence tag library of Coptotermesformosanus, a xylophagous lower termite species. Functional analyses of these genes not only shed light on the mechanisms the insect employs to successfully use cellulosic materials as energy sources, which may serve as strategic targets for designing molecular-based bio-pesticides, but also enrich discoveries of new cellulolytic enzymes for conversion ofbiomass into biofuel. Our study demonstrated that cellulose could be converted to glucose by two recombinant endogenous glycosyl hydrolases （endo-β- 1,4 glucanase in GH9 and β-glucosidase in GH1）. While the former cleaved cellulose to cellobiose and cellotriose, the resulting simple cellodextrins were digested to glucose. Both of the Escherichia coli-expressed recombinant proteins showed properties that could be incorporated in a glucose-based ethanol production program.

关键词： biofuel cellulose digestion endo-β-1,4 glucanase,β-glucosidase termite