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Variant selection in laser powder bed fusion of non-spherical Ti-6Al-4V powder

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Journal of Materials Science & Technology 2023年第16期147卷 56-67页

作者： Mohammadreza Asherloo Ziheng Wu Julian E.C.Sabisch Iman Ghamarian anthony d.Rollett Amir Mostafaei department of Mechanical Materials and Aerospace EngineeringIllinois Institute of Technology10 W 32nd StreetChicagoIL 60616United States Materials Engineering division Lawrence Livermore National Laboratory7000 East AveLivermoreCA 94550United States Samuel Roberts Noble Microscopy Laboratory University of OklahomaNormanOK 73019United States School of Aerospace and Mechanical Engineering University of OklahomaNormanOK 73019United States department of Materials Science and Engineering Carnegie Mellon UniversityPittsburghPA 15213United States

The presence ofα/αon priorβ/βgrain boundaries directly impacts the final mechanical properties of the titanium ***β/βgrain boundary variant selection of titanium alloys has been assumed to be unlikely owing to the high cooling rates in laser powder bed fusion(L-PBF).However,we hypothesize that powder characteristics such as morphology(non-spherical)and particle size(50–120μm)could affect the initial variant selection in L-PBF processed Ti-6Al-4V alloy by locally altering the cooling *** the high cooling rate found in L-PBF,results showed the presence ofβ/βgrain boundaryαlath growth inside two adjacent priorβ*** backscatter diffraction micrographs confirmed the presence ofβ/βgrain boundary variant selection,and synchrotron X-ray high-speed imaging observation revealed the role of the“shadowing effect”on the locally decreased cooling rate because of keyhole depth reduction and the consequentβ/βgrain boundaryαlath *** self-accommodation mechanism was the main variant selection driving force,and the most abundantα/αboundary variant was type 4(63.26°//[10553¯]).The dominance of Category IIαlath clusters associated with the type 4α/αboundary variant was validated using the phenomenological theory of martensite transformations and analytical calculations,from which the stress needed for theβ→αtransformation was calculated.

关键词： Variant selection Phase formation Additive Manufacturing Hydride-dehydride powder Texture analysis Electron backscattered diffraction

Helicobacter pylori:High dose amoxicillin does not improve primary or secondary eradication rates in an Irish cohort

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World Journal of Clinical Cases 2024年第16期12卷 2773-2779页

作者： Conor Costigan Aoife M O'Sullivan Jim O'Connell Shreyashee Sengupta Thomas Butler Stephen Molloy Fintan John O'Hara Barbara Ryan Niall Breslin Sarah O'donnell anthony O'Connor Sinead Smith deirdre McNamara Trinity Academic Gastroenterology Group School of Medicine-Trinity College DublinDublin D2Ireland department of Gastroenterology Tallaght University HospitalDublin D24 NR0AIreland

BACKGROUNd Helicobacter pylori(***)eradication rates have fallen globally,likely in large part due to increasing antibiotic resistance to traditional *** areas of high clarithromycin and metronidazole resistance such as ours,Maastricht VI guidelines suggest high dose amoxicillin dual therapy(HdAdT)can be considered,subject to evidence for local *** this study we assess efficacy of HdAdT therapy for *** eradication in an Irish *** To assess the efficacy of HdAdT therapy for *** eradication in an Irish cohort as both first line,and subsequent therapy for patients diagnosed with *** All patients testing positive for *** in a tertiary centre were treated prospectively with HdAdT(amoxicillin 1 g tid and esomeprazole 40 mg bid×14 d)over a period of 8 *** was confirmed with Urea Breath Test at least 4 wk after cessation of therapy.A delta-over-baseline>4%was considered *** demographics and treatment outcomes were recorded,analysed and controlled for basic demographics and prior *** *** One hundred and ninety-eight patients were identified with *** infection,10 patients were excluded due to penicillin allergy and 38 patients refused follow up *** all 139 were included in the analysis,55%(n=76)were female,mean age was 46.6 ***,93(67%)of patients were treatment-naïve and 46(33%)had received at least one previous course of *** groups were statistically ***-reported compliance with HdAdT was 97%,mild side-effects occurred in 7%.There were no serious adverse drug *** the eradication rate for our cohort was 56%(78/139).Eradication rates were worse for those with previous treatment[43%(20/46)vs 62%(58/93),P=0.0458,odds ratio=2.15].Age and Gender had no effect on eradication *** Overall eradication rates with HdAdT were *** being a simple and possibly better tolerated regime,these results do not

关键词： Helicobacter pylori eradication Helicobacter pylori High dose amoxicillin High dose amoxicillin dual therapy Triple therapy

Ethical challenges in mass drug administration for reducing childhood mortality:a qualitative study

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Infectious diseases of Poverty 2022年第5期11卷 93-94页

作者： Ahmed Alasmar Alex C.Kong anthony d.So Matthew deCamp 不详 division of General Internal Medicine and Center for Bioethics and Humanities Department of MedicineUniversity of Colorado School of MedicineUniversity of Colorado Anschutz Medical Campus13080 E.19th AveMail Stop B137AuroraCO 80045USA

Background:Mass drug administration(MdA)of medications to entire at-risk communities or populations has shown promise in the control and elimination of global infectious *** of the broad-spectrum antibiotic azithromycin has demonstrated the potential to reduce childhood mortality in children at risk of premature death in some global ***,MdA of antibiotics raises complex ethical challenges,including weighing near-term benefts against longer-term risks—particularly the development of antimicrobial resistance that could diminish antibiotic efectiveness for current or future *** aim of this study was to understand how key actors involved in MdA perceive the ethical challenges of ***:We conducted 35 semi-structured interviews from december 2020–February 2022 with investigators,funders,bioethicists,research ethics committee members,industry representatives,and others from both highincome countries(HICs)and low-and middle-income countries(LMICs).Interview participants were identifed via one of seven MdA studies purposively chosen to represent diversity in terms of use of the antibiotic azithromycin;use of a primary mortality endpoint;and whether the study occurred in a high child mortality *** were analyzed using constructivist grounded theory ***:The most frequently discussed ethical challenges related to meaningful community engagement,how to weigh risks and benefts,and the need to target MdA We developed a concept map of how participants considered ethical issues in MdA for child mortality;it emphasizes MdA’s place alongside other public health interventions,empowerment,and *** over an ethical double standard in weighing risks and benefts emerged as a unifying theme,albeit one that participants interpreted in radically diferent *** thought MdA for reducing child mortality was ethically obligatory;others suggested it was ***:Ethical challenges raised by MdA of antib

关键词： Antimicrobial resistance decolonizing global health Mass drug administration Child mortality Ethics Global health equity

Inducing imperfections in germanium nanowires

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Nano Research 2017年第5期10卷 1510-1523页

作者： Subhajit Biswas Sven Barth Justin d. holmes Materials Chemistry & Analysis Group Department of Chemistry and the Tyndall National lnstitute University College Cork Cork Ireland AMBER@CRANN Trinity College Dublin Dublin 2 Ireland Vienna University of Technology Institute of Materials Chemistry Getreidemarkt 9/BCI02 1060 Vienna Austria

Nanowires with inhomogeneous heterostructures such as polytypes and periodic twin boundaries are interesting due to their potential use as components for optical, electrical, and thermophysical applications. Additionally, the incorporation of metal impurities in semiconductor nanowires could substantially alter their electronic and optical properties. In this highlight article, we review our recent progress and understanding in the deliberate induction of imperfections, in terms of both twin boundaries and additional impurities in germanium nanowires for new/enhanced functionalities. The role of catalysts and catalyst-nanowire interfaces for the growth of engineered nanowires via a three-phase paradigm is explored. Three-phase bottom-up growth is a feasible way to incorporate and engineer imperfections such as crystal defects and impurities in semiconductor nanowires via catalyst and/or interfacial manipulation. ＂Epitaxial defect transfer＂ process and catalyst-nanowire interfacial engineering are employed to induce twin defects parallel and perpendicular to the nanowire growth axis. By inducing and manipulating twin boundaries in the metal catalysts, twin formation and density are controlled in Ge nanowires. The formation of Ge polytypes is also observed in nanowires for the growth of highly dense lateral twin boundaries. Additionally, metal impurity in the form of Sn is injected and engineered via third-party metal catalysts resulting in above-equilibrium incorporation of Sn adatoms in Ge nanowires. Sn impurities are precipitated into Ge bi-layers during Ge nanowire growth, where the impurity Sn atoms become trapped with the deposition of successive layers, thus giving an extraordinary Sn content （〉6 at.%） in Ge nanowires. A larger amount of Sn impingement （〉9 at.%） is further encouraged by utilizing the eutectic solubility of Sn in Ge along with impurity trapping.

关键词： germamum nanowire vapor-liquid-solid (VLS)growth twinning impurity incorporation

24-Hour movement behaviours and COVId-19 among children in the Kingdom of Saudi Arabia:A repeat cross-sectional study

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Sports Medicine and Health Science 2022年第3期4卷 177-182页

作者： Yazeed A.Alanazi Anne-Maree Parrish anthony d.Okely Early Start and School of Health&Society University of WollongongWollongongNSW2522Australia College of Sport Science and Physical Activity King Saud UniversityRiyadh12372Saudi Arabia Illawarra Health and Medical Research Institute WollongongNSW2522Australia

This study investigated how children's 24-hour(24-h)movement behaviours were affected by SARS-CoV-2(COVId-19)in the Kingdom of Saudi *** research examined 24-h movement behaviours in Saudi Arabia seven months after the World Health Organization(WHO)declared COVId-19 a global *** repeat cross-sectional study examined changes in 24-h movement behaviours 12 months after the WHO *** Time 2 survey repeated five months(1 March–15 May 2021)after Time 1 survey(1 October–11 November 2020).The survey was distributed to parents of children aged 6–12 years across Saudi Arabia via an online *** were classified as meeting 24-h movement guidelines if they reported uninterrupted sleep for 9–11 h per night,2 h of recreational sedentary screen time(RST)per day and-60 min of moderate-to vigorous-intensity physical activity(MVPA)per day.A total of 1045 parents from all regions of Saudi Arabia responded(42.4%).Only 1.8%of children met all components of the guidelines,compared to 3.4%in Time *** the present study,girls spent more days per week in MVPA-60 min duration than boys(3.0 vs 2.6;p=0.025),while boys had spent more days per week engaged in activities that strengthened muscle and bone than girls(3.0 vs 2.8;p=0.019).Healthy levels of physical activity(PA),sedentary behaviour(SB)and sleep further declined in Saudi children five months after the Time 1 *** challenges require urgent intervention to ensure children's movement behaviours improve as Saudi Arabia moves out of the COVId-19 pandemic.

关键词： Sleep Sedentary behaviour Physical activity Children COVId-19

Synthesis of phosphonated graphene oxide by electrochemical exfoliation to enhance the performance and durability of high-temperature proton exchange membrane fuel cells

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Journal of Energy Chemistry 2023年第1期76卷 448-458,I0011页

作者： Jianuo Chen Zunmin Guo Maria Perez-Page Yifeng Jia Ziyu Zhao Stuart M.holmes department of Chemical Engineering and Analytical Science University of ManchesterOxford RoadManchester M139PLUnited Kingdom Chemistry Research Laboratory Department of ChemistryUniversity of Oxford12 Mansfield RoadOxford OX13TAUnited Kingdom

The doping of functionalized graphene oxide(GO)in the membranes becomes a promising method for improving the performance of high-temperature proton exchange membrane fuel cells(HT-PEMFC).Phosphonated graphene oxide(PGO)with a P/O ratio of 8.5%was quickly synthesised by one-step electrochemical exfoliation based on a three-dimensiaonal(3d)printed reactor and natural graphite *** with the GO prepared by the two-step electrochemical exfoliation method,the PGO synthesized by the one-step electrochemical exfoliation can better improve the performance of the membrane-electrode-assembly(MEA)based on the polybenzimidazole(PBI)membrane in the *** doping of 1.5 wt%GO synthesised by electrochemical exfoliation with the 2-step method or reactor method in PBI increased the peak power density by 17.4%or 35.4%compared to MEA based on pure PBI membrane at 150℃,*** addition,the doping of PGO in PBI improves its durability under accelerated stress test(AST).

关键词： Electrochemical exfoliation Phosphonated graphene oxide High-temperature fuel cells

An Accurate and Scalable direction-Splitting Solver for Flows Laden with Non-Spherical Rigid Bodies–Part 1:Fixed Rigid Bodies

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Communications in Computational Physics 2023年第9期34卷 1079-1132页

作者： Aashish Goyal anthony Wachs department of Chemical and Biological Engineering University of British Columbia2360 East MallV6T 1Z3VancouverBritish ColumbiaCanada department of Mathematics University of British Columbia1984 Mathematics RoadV6T 1Z4VancouverBritish ColumbiaCanada

Particle-resolved direct numerical flow solvers predominantly use a projection method to decouple the non-linear mass and momentum conservation *** computing performance of such solvers often decays beyond O(1000)cores due to the cost of solving at least one large three-dimensional pressure Poisson problem per time *** parallelization may perform moderately well only or even poorly sometimes despite using an efficient algebraic multigrid preconditioner[38].We present an accurate and scalable solver using a direction splitting algorithm[12]to transform all three-dimensional parabolic/elliptic problems(and in particular the elliptic pressure Poisson problem)into a sequence of three one-dimensional parabolic sub-problems,thus improving its scalability up to multiple thousands of *** employ this algorithm to solve mass and momentum conservation equations in flows laden with fixed non-spherical rigid *** consider the presence of rigid bodies on the(uniform or non-uniform)fixed Cartesian fluid grid by modifying the diffusion and divergence stencils on the impacted grid node near the rigid body *** to[12],we use a higher-order interpolation scheme for the velocity field to maintain a secondorder stress estimation on the particle boundary,resulting in more accurate dimensionless coefficients such as drag C_(d)and lift C_(l).We also correct the interpolation scheme due to the presence of any nearby particle to maintain an acceptable accuracy,making the solver robust even when particles are densely packed in a sub-region of the computational *** present classical validation tests involving a single or multiple(up to O(1000))rigid bodies and assess the robustness,accuracy and computing speed of the *** further show that the direction Splitting solver is∼5 times faster on 5120 cores than our solver[38]based on a classical projection method[5].

关键词： Highly scalable solver particle-laden flow particle resolved direct numerical simulation incompressible flow non-spherical rigid bodies

Effect of lignite amendment on carbon and nitrogen mineralization from raw and composted manure during incubation with soil

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Pedosphere 2022年第5期32卷 785-795页

作者： Robert IMPRAIM anthony WEATHERLEY deli CHEN Helen SUTER School of Agriculture and Food Faculty of Veterinary and Agricultural Sciences.The University of MelbourneParkvilleVictoria 3010(Australia)

The application of animal manure as a source of plant nutrients requires the determination of the amount and pattern of nutrient mineralization from manure.A laboratory incubation study was conducted to investigate the influence of lignite amendment and lignite type on carbon(C)and nitrogen(N)mineralization in raw(feedstock)and composted cattle manure following application to soil at 30 and 60 t ha^(-1).The mineralization of C and N was determined by measuring changes in CO_(2) evolution and mineral N(NH_(4)^(+)-N+NO_(3)^(-)-N)over 40 *** results showed that lignite amendment suppressed the amount of manure C mineralized in both feedstock and compost,with the effect being more pronounced in the *** the 40-d incubation,the percentage of applied C mineralized was 26.4%-27.8%and 16.3%-21.4%in unamended and lignite-amended feedstocks,*** corresponding C mineralized in the composts was 12.4%-14.1%and 3.5%-6.5%.Lignite had no significant effect on the net N mineralized in compost(4.8%-6.7%and2.5%-7.8%in unamended and lignite-amended composts,respectively).Lignite had either no effect or increased the net N mineralized in feedstock(from3.2%-8.7%without lignite to 10.4%-13.5%)depending on the type of lignite *** study suggests that using lignite-amended manure,especially when composted,has the potential to build up soil organic C without limiting the availability of mineral N.

关键词： CO_(2)evolution manure mineralization mineral N nitrification soil incubation

The effect of protein oxidation on the formation of advanced glycation end products after chicken myofibrillar protein glycation

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Food Science and Human Wellness 2023年第5期12卷 1571-1579页

作者： Zongshuai Zhu anthony Pius Bassey Ming Huang Iftikhar Ali Khan College of Food Science and Technology Nanjing Agricultural UniversityNanjing 210095China National R&d Center for Poultry Processing Technology Nanjing Huangjiaoshou Food Science and Technology Co.Ltd.Nanjing 211200China Institution of Agricultural Products Processing Jiangsu Academy of Agricultural SciencesNanjing 210095China

Investigation that protein oxidation to the formation of advanced glycation end products(AGEs)after chicken myofibrillar protein glycation is *** of protein oxidation induced by different concentrations of hydroxyl radicals(·OH)were developed after the chicken myofibrillar protein mild glycation(MPG).Results exhibited that levels of AGEs and surface hydrophobicity(H_(0))steadily increased with the a ddition of h ydrogen peroxide(H_(2)O_(2))***,levels of s ulfhydryl group,free amino group,and particle size gradually decreased with the H_(2)O_(2)*** protein carbonyl value increased in H_(2)O_(2)concentration until 10 mmol/***'s correlation indicated that MPG structure modification(unfolding and degradation)induced by protein oxidation were significantly positively correlated with AGEs concentration(Pd to hypothesize t he effect of protein oxidation on the formation of AGEs under MPG conditions.

关键词： Protein oxidation Glycated myofibrillar protein Structure changes Advanced glycation end products