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Machine-learned multi-system surrogate models for materials prediction

丛书名： 198 p. :

1000年

作者： alexander L. g.

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npj Computational Materials 2019年第1期5卷 702-707页

作者： Chandramouli Nyshadham Matthias Rupp Brayden Bekker alexander v.Shapeev Tim Mueller Conrad W.Rosenbrock gábor Csányi David W.Wingate gus L.W.Hart Department of Physics and Astronomy Brigham Young UniversityProvoUT 84602USA Fritz Haber Institute of the Max Planck Society Faradayweg 4–614195 BerlinGermany Skolkovo Institute of Science and Technology Skolkovo Innovation CenterBuilding 3Moscow 143026Russia Department of Materials Science and Engineering Johns Hopkins UniversityBaltimoreMD 21218USA Engineering Laboratory University of CambridgeTrumpington StreetCambridge CB21PZUK Computer Science Department Brigham Young UniversityProvoUT 84602USA Citrine Informatics 702 Marshall StreetRedwood CityCA 94063USA

Surrogate machine-learning models are transforming computational materials science by predicting properties of materials with the accuracy of ab initio methods at a fraction of the computational *** demonstrate surrogate models that simultaneously interpolate energies of different materials on a dataset of 10 binary alloys(AgCu,AlFe,AlMg,AlNi,AlTi,CoNi,CuFe,CuNi,Fev,and NbNi)with 10 different species and all possible fcc,bcc,and hcp structures up to eight atoms in the unit cell,15,950 structures in *** find that the deviation of prediction errors when increasing the number of simultaneously modeled alloys isv/*** state-of-the-art materials representations and learning algorithms were found to qualitatively agree on the prediction errors of formation enthalpy with relative errors of<2.5% for all systems.

关键词： alloys prediction CoNi

Synergistic effect of chitin nanofibers and polyacrylamide on electrochemical performance of their ternary composite with polypyrrole

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Journal of Energy Chemistry 2018年第3期27卷 843-853页

作者： Michael A.Smirnov Maria P.Sokolova Natalya v.Bobrova alexander M.Toikka Pierfrancesco Morganti Erkki Lahderanta Lappeenranta University of Technology 53850 LappeenrantaFinland Institute of Macromolecular compounds Russian Academy of Sciences199004 Saint PetersburgRussia St.Petersburg State University PeterhofSaint Petersburg 198504Russia Dermatological Institute II University of Naples80138 NaplesItaly

Development of simple methods for preparation of polymeric electrode materials with nanofibrous network structure is a perspective way toward cheap supercapacitors with high specific capacitance and energy density. In this work one-pot synthesis of electroactive ternary composite based on polypyrrole, polyacrylamide and chitin nanofibers with beneficial morphology was elaborated. Ternary system demonstrates better electrochemical performance in comparison with both polypyrrole–polyacrylamide and polypyrrole–chitin binary composites. Possible mechanism of synergistic effect of simultaneous influence of polyacrylamide and chitin nanofibers on the formation of composite＇s structure is *** highest attained specific capacitance of electroactive polypyrrole in ternary composite reached 249 F/g at 0.5 A/g and 150 F/g at 32 A/g. Symmetrical supercapacitor was assembled using the elaborated electrode material. High specific capacitance 89 F/g and good cycling stability with capacitance retention of 90% after 3000 cycles at 2 A/g were measured.

关键词： Energy materials Nanocomposites Natural fibers Electrical properties

Clustering of Pathogen-Response genes in the genome of Arabidopsis thaliana

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Journal of Integrative Plant Biology 2011年第10期53卷 824-834页

作者： Olga A.Postnikova Natalia Y.Minakova alexander M.Boutanaev Lev g.Nemchinov United States Department of Agriculture Agricultural Research ServicePlant Sciences InstituteMolecular Plant Pathology Laboratory Institute of Basic Biological Problems Russian Academy of Sciences

Previously, we used heterologous expressed sequence tag （EST） mapping to generate a profile of 4 935 pathogen-response genes of Arabidopsis thaliana. In this work, we performed a computer analysis of this profile, revealing 1594 non-homologous clustered genes distributed among all A. thafiana chromosomes, whose co-regulation may be related to host responses to pathogens. To supplement computer data, we arbitrarily selected two clusters and analyzed their expression levels in A. thaliana ecotypes Col-0 and C24 during infection with the yellow strain of Cucumber mosaic virus CMv（Y）. Ecotype Col-0 is susceptible to CMv（Y）, whereas C24 contains the dominant resistance gene RCY1. Upon infection with CMv（Y）, all clustered genes were significantly activated in the resistant ecotype C24. In addition, we demonstrated that posttranslational histone modifications associated with trimethylation of histone H3 lysine 27 are most likely involved in regulation of several cluster genes described in this study. Overall, our experiments indicated that pathogen-response genes in the genome of A. thaliana may be clustered and co-regulated.

关键词： CMv H3K27me3 heterologous EST mapping clustering of defense-related genes.

Planning to Plan-Integrating Control Flow

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Tsinghua Science and Technology 2003年第1期8卷 1-7页

作者： alexander Nareyek Computer Science Department Carnegie Mellon University

In many planning situations, computation itself becomes a resource to be planned and scheduled. We model such computational resources as conventional resources which are used by control-flow actions, e.g., to direct the planning process. Control-flow actions and conventional actions are planned/scheduled in an integrated way and can interact with each other. Control-flow actions are then executed by the planning engine itself. The approach is illustrated by examples, e.g., for hierarchical planning, in which tasks that are temporally still far away impose only rough constraints on the current schedule, and control-flow tasks ensure that these tasks are refined as they approach the current time. Using the same mechanism, anytime algorithms can change appropriate search methods or parameters over time, and problems like scheduling critical time-outs for garbage collection can be made part of the planning itself.

关键词： meta-planning resource-bounded reasoning online planning integrated planning, sensing and execution integrated planning and scheduling hierarchical planning anytime algorithms local search metaheuristics

New Findings of Latest Early Olenekian(Early Triassic)Fossils in South Primorye,Russian Far East,and Their Stratigraphical Significance

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Journal of Earth Science 2021年第3期32卷 554-572页

作者： Yuri D.Zakharov Liana g.Bondarenko alexander M.Popov Olga P.Smyshlyaeva Far Eastern geological Institute Far Eastern BranchRussian Academy of SciencesVladivostok 690022Russia

Information on latest early Olenekian(latest Smithian)ammonoids is available apparently from only seven regions of the world,including South *** Smithian evidences on this topic are recorded from the West SMID(abbreviation from the Russian name of the quarry:"Building Materials and Details"),East SMID and golyj Cape areas in South *** provides additional information on systematic composition of latest Smithian ammonoid,as well as conodont and brachiopod assemblages from the recently identified Shimanskyites shimanskyi Zone,located between lower Olenekian Anasibirites nevolini Zone and upper Olenekian Tirolites subcassianus *** are many common ammonoid species in the Shimanskyites shimanskyi Zone and the underlying Anasibirites nevolini Zone,e.g.,Prosphingitoides sp.,Arctoceras septentrionale(Diener),Churkites syskoi Zakharov et Shigeta,Submeekoceras?subhhydaspis(Kiparisova),Prionites markevichi Zakharov et Smyshlyaeva,?Anasibirites?simanenkoi Zakharov et Smyshlyaeva,Xenoceltites?subvariocostatus Zakharov et Smyshlyaeva,and Mianwaliites zimini Zakharov et *** base of the Shimanskyites shimanskyi Zone,marked by a negativeδ13Corg excursion in the Kamenushka-2 Section by our previous study,coincides with the FO(first occurrence)of ammonoids Shimanskyites shimanskyi Zakharov et Smyshlyaeva and glyptophiceras ***(Waagen)and conodont Hindeodella budurovi *** zone is characterized additionally by some fossils common for the overlying upper Olenekian Tirolites subcassianus Zone:ammonoids of the genus Kamenushkaites,brachiopods Bittnerihyris margaritovi(Bittner)and Lepismatina *** conodont?Neogondolella?(=?Borinella)jubata *** latest Smithian ammonoids recorded from the Shimanskyites shimanskyi Zone totally consist of 30 taxa belonging to 11 families(Sageceratidae,Ussuiriidae,Aspenitidae,Paranannitidae,Arctoceratidae,Proptychitidae,?galfetitidae,Prionitidae,?Kashmiritidae,Xenoceltitidae and Palaeophyllitidae).Th

关键词： ammonoids conodonts brachiopods biostratigraphy Smithian Russia

激光辐射波长和脉冲寿命对碲化镉熔化阈值的影响

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材料导报 2024年第7期38卷 40-45页

作者：列维茨基·谢尔盖曹泽祥柯巴·亚历山大柯巴·玛丽亚乌克兰国家科学院半导体物理研究所基辅03028 乌克兰国立技术大学物理技术学院基辅03058 乌克兰国民警卫研究所国家安全系基辅03028

碲化镉的相对分子量为240,密度为5.885 g/cm^(3),熔点为1092℃。碲化镉是一种Ⅱ-Ⅵ族的化合物半导体材料,属于直接带隙型,带隙宽度为1.56 ev。碲化镉是制造X射线、伽马射线和红外线探测器的基本材料。对碲化镉的特别关注主要是由于其大... 详细信息

碲化镉的相对分子量为240,密度为5.885 g/cm^(3),熔点为1092℃。碲化镉是一种Ⅱ-Ⅵ族的化合物半导体材料,属于直接带隙型,带隙宽度为1.56 ev。碲化镉是制造X射线、伽马射线和红外线探测器的基本材料。对碲化镉的特别关注主要是由于其大原子数和大的光电吸收截面。在基于CdTe的伽马辐射势垒探测器结构中,其表面的处理方法之一是纳秒激光照射,在某些情况下,纳秒激光照射可以在触点(Ag、In、Au)和势垒形成的技术处理阶段优化所需的表面参数。另一种方法是在脉冲激光照射下在碲化镉表面形成有序的纳米结构。对基于半导体及其结构的脉冲激光器,可根据其不同的脉冲持续时间τ_(p)和辐射波长λ将其分类。例如,红宝石激光器(λ=694 nm)、钕激光器(一次谐波1064 nm和两次谐波532 nm)、准分子KrF激光器(248 nm)和XeF激光器(351 nm)等,其脉冲持续时间分别为7、20、80、120 ns。这些激光器常被应用于表面修饰等领域。因此,往往有必要事先知道或至少估计在脉冲激光辐射下碲化镉表面的熔化温度和阈值,这取决于激光脉冲持续时间τ_(p)、辐射波长(光吸收系数α(λ))以及碲化镉表面本身的电物理参数,特别是表面重组率S和非平衡电荷载流子的寿命。这些参数取决于表面处理的方法和掺杂物的浓度。在上述情况下,实验研究是非常耗费人力和时间的,因此基于τ_(p)、α(λ)和碲化镉表面本身的电物理参数对融化阈值th和表面温度进行理论计算变得非常重要。本工作采用激光照射碲化镉,辐射波长为300~800 nm,脉冲持续时间为7~120 ns。为了以非破坏性的和有效的方法来管理接近表面层状态的CdTe,在T=80 K下进行了光致发光实验。为了监测熔化阈值,研究了由Acrorad公司制造和抛光的尺寸为5 mm×5 mm×0.5 mm的Cl补偿p-CdTe(111)单晶的光致发光光谱。经过研究发现,在激光脉冲寿命从7ns到1μs的范围内,CdTe熔化阈值明显取决于光吸收系数α(λ)。因为在脉冲寿命长于1μs的情况下,热扩散深度明显大于CdTe中的激光辐射穿透深度,并开始依赖于反射系数R(λ)。对于较短的激光脉冲长度τ_(p),当辐射波长λ变化时,熔化阈值会发生显著变化。同时,非平衡过剩载流子参数的变化(如表面重组速度S从10^(3)m/s增加到10^(5)m/s,还有扩散深度LD从0.4μm增加到2μm)会对CdTe熔化阈值产生至少25%的影响。而且红宝石激光的脉冲持续时间在(20±5)ns区间内的变化导致相对熔化阈值的变化(ΔIth/Ith)为35%。CdTe熔化阈值的计算值可以有效地被用于优化脉冲激光对晶体的表面处理与掺杂。

关键词：碲化镉熔化阈值脉冲激光辐照半导体激光掺杂

Characterization and Electrochemical Properties of Nanostructured Zr-Doped Anatase TiO_2 Tubes Synthesized by Sol–gel Template Route

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Journal of Materials Science & Technology 2017年第6期33卷 527-534页

作者： Denis P.Opra Sergey v.gnedenkov Sergey L.Sinebryukhov Elena I.voit alexander A.Sokolov Evgeny B.Modin Anatoly B.Podgorbunsky Yury v.Sushkov veniamin v.Zheleznov Institute of Chemistry Far Eastern Branch of Russian Academy of Sciences Far Eastern Federal University National Research Centre "Kurchatov Institute"

A series of nanostructured Zr-doped anatase TiO_2 tubes with the Zr/Ti molar ratio of 0.01, 0.02, 0.03, and0.09 were prepared by a sol–gel technology on a carbon fiber template. The electrochemical performance of Zr-doped anatase TiO_2 as anodes for rechargeable lithium batteries was investigated and compared with undoped titania. Tests represented that after 35-fold charge/discharge cycling at C/10 the reversible capacity of Zr-doped titania（Zr/Ti = 0.03） reaches 135 m A h g^（-1）, while the capacity of undoped titania（Zr/Ti = 0） yielded only 50 m A h g^（-1）. Based on the results of the physicochemical investigation, three reasons of improving electrochemical performance of Zr-doped titania were suggested. According to the scanning electron microscopy and transmission electron microscopy, Zr^（4＋） doping induces a decrease in nanoparticle size, which facilitates the Li＋diffusion. The Raman investigations show the more open structure of Zr-doped TiO_2 as compared to undoped titania due to changing of the unit cell parameters, that significantly affects on the reversibility of the insertion/extraction process. The electrochemical impedance spectroscopy results indicate that substitution of Zr^（4＋） for Ti^（4＋） into anatase TiO_2 has favorable effects on the conductivity.

关键词： Li-ion batteries Anatase titania Nanostructured materials Sol–gel template process Doping Electrochemical performance

Engineering osteoarthritic cartilage model through differentiating senescent human mesenchymal stem cells for testing disease-modifying drugs

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Science China(Life Sciences) 2022年第2期65卷 309-327页

作者： Ning Wang Yuchen He Silvia Liu Meagan J.Makarcyzk guanghua Lei alexander Chang Peter g alexander Tingjun Hao Anne-Marie Padget Nuria de Pedro Tsapekos Menelaos Hang Lin Department of Orthopaedic Surgery University of Pittsburgh School of MedicinePittsburgh PA 15219USA Department of Orthopedic Surgery Xiangya HospitalCentral South UniversityChangsha 410008China Department of Pathology University of Pittsburgh School of MedicinePittsburgh PA 15219USA Department of Bioengineering University of Pittsburgh Swanson School of EngineeringPittsburgh PA 15219USA Department of Bioinformatics University of Pittsburgh School of MedicinePittsburgh PA 15219USA Mcgowan Institute for Regenerative Medicine University of Pittsburgh School of MedicinePittsburgh PA 15219USA Department of Biology University of Pittsburgh Dietrich School of Arts and SciencePittsburgh PA 15219USA Department of Research B2B Life Length SLMadrid 28010Spain Xiangya Third Hospital Central South UniversityChangsha 410013China

Significant cellular senescence has been observed in cartilage harvested from patients with osteoarthritis(OA).In this study,we aim to develop a senescence-relevant OA-like cartilage model for developing disease-modifying OA drugs(DMOADs).Spe-cifically,human bone marrow-derived mesenchymal stromal cells(MSCs)were expanded in vitro up to passage 10(P10-MSCs).Following their senescent phenotype formation,P10-MSCs were subjected to pellet culture in chondrogenic *** from qRT-PCR,histology,and immunostaining indicated that cartilage generated from P10-MSCs displayed both senescent and OA-like phenotypes without using other OA-inducing agents,when compared to that from normal passage 4(P4)-***,the same gene expression differences observed between P4-MSCs and P10-MSC-derived cartilage tissues were also observed between the preserved and damaged OA cartilage regions taken from human samples,as demonstrated by RNA sequencing data and other analysis ***,the utility of this senescence-initiated OA-like cartilage model in drug development was assessed by testing several potential DMOADs and *** results suggest that pre-existing cellular senescence can induce the generation of OA-like changes in *** P4-and P10-MSCs derived cartilage models also represent a novel platform for predicting the efficacy and toxicity of potential DMOADs on both preserved and damaged cartilage in humans.

关键词： osteoarthritis MSC senescence cartilage tissue engineering disease-modifying OA drug senolytic

Enhanced expression of interleukin-18 in serum and pancreas of patients with chronic pancreatitis

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World Journal of gastroenterology 2006年第40期12卷 6507-6514页

作者： alexander Schneider Stephan L Haas Ralf Hildenbrand Sren Siegmund Iris Reinhard Helmut Nakovics Manfred v Singer Peter Feick Department of Medicine II (gastroenterology Hepatology and Infectious Diseases) Univer-sity Hospital of Heidelberg at Mannheim Mannheim Germany Institute of Pathology University Hospital of Heidelberg at Mannheim Mannheim Germany Central Institute of Mental Health Mannheim Germany

AIM： To investigate interleukin-18 （IL-18） in patients with chronic panreatitis （CP）. METHODS： We studied 29 patients with CP and 30 healthy controls. Peripheral blood mononuclear cells （PBMC） were isolated and incubated with 50 mmol/L ethanol, lipopolysaccharide （LPS）（doses 25 g/L, 250 g/L, 2500 g/L） and both agents for 24 h. Levels of IL-18 in the supernatants, and levels of IL-18, IL-12, interferon （IFN）-T and soluble CD14 in the serum were analysed by EI_ISA technique. Expression of IL-18 in PBMC was investigated by reverse-transcription （RT）-PCR. IL-18 protein levels in CP tissue and in normal pancreas were studied by ELISA technique. IL-18 levels in PBMC and pancreatic tissue were determined by Westernblot. Immunohistochemistry for pancreatic IL-18 expression was performed.RESULTS： In patients, IL-18 serum levels were significantly enhanced by 76% （mean： 289.9 ± 167.7 ng/L） compared with controls （mean： 165.2 ± 43.6 ng/L; P 〈 0.0005）. IL-12 levels were enhanced by 25% in patients （18.3 ± 7.3 ng/L） compared with controls （14.7 ± 6.8 ng/L, P = 0.0576） although not reaching the statistical significance. IFN-γ, and soluble CD14 levels were not increased. In vitro, LPS stimulated significantly and dosedependently IL-18 secretion from PBMC. Incubation with ethanol reduced LPS-stimulated IL-18 secretion by about 50%. The mRNA expression of IL-18 in PBMC and the response of PBMC to ethanol and LPS was similar in CP patients and controls. In PBMC, no significant differences in IL-18 protein levels were detected between patients and controls. IL-18 protein levels were increased in CP tissues compared to normal pancreatic tissues. IL-18 was expressed by pancreatic acinar cells and by infiltrating inflammatory cells within the pancreas. CONCLUSION： IL-18 originates from the chronically inflammed pancreas and appears to be involved in the fibrotic destruction of the organ.

关键词： Chronic pancreatitis Cytokines Interleukin- 18 Pancreatic fibrosis