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Solvation Effects on the Dielectric Constant of 1 M LiPF6 in Ethylene Carbonate:Ethyl Methyl Carbonate 3:7

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Energy & Environmental Materials 2024年第1期7卷 253-256页

作者： Julian Self nathan T.Hahn Kristin A.Persson Department of Chemical Engineering Polytechnique MontrealMontrealQC H3T 1J4Canada Department of Materials Science and Engineering University of CaliforniaBerkeleyCA 94720USA Energy Technologies Area Lawrence Berkeley National LaboratoryBerkeleyCA 94720USA Material Physical and Chemical Sciences CenterSandia National LaboratoriesAlbuquerqueNM 87185USA

we report the dielectric constant of 1 M LiPF_(6)in EC:EMC 3∶7 w/w(ethylene carbonate/ethyl methyl carbonate)in addition to neat EC:EMC 3∶7 w/*** three Debye relaxations,the static permittivity value,or dielectric constant,is extrapolated to 18.5,which is compared to 18.7 for the neat solvent *** EC solvent is found to strongly coordinate with the Li^(+)cations of the salt,which results in a loss of dielectric contribution to the ***,the small amplitude and large uncertainty in relaxation frequency for EMC cloud definitive identification of the Li^(+)solvation ***,the loss of the free EC permittivity contribution due to Li^(+)solvation is almost completely balanced by the positive contribution of the associated LiPF_(6)salt,demonstrating that a significant quantity of dipolar ion pairs exists in 1 M LiPF_(6)in EC:EMC 3∶7.

关键词： batteries dielectric relaxation spectroscopy electrolytes

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BMPRⅡ^(+)neural precursor cells isolated and characterized from organotypic neurospheres:an in vitro model of human fetal spinal cord development

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Neural Regeneration Research 2024年第2期19卷 447-457页

作者： Michael w.weible II Michael D.Lovelace Hamish D.Mundell Tsz wai Rosita Pang Tailoi Chan-Ling Bosch Institute Discipline of Anatomy and Histology(F13)University of SydneySydneyNSWAustralia School of Environment and Science Griffith UniversityNathanQLDAustralia Discipline of Medicine Nepean Clinical SchoolFaculty of Medicine and HealthUniversity of SydneyKingswoodNSWAustralia New South wales Brain Tissue Resource Centre School of Medical SciencesFaculty of Medicine and HealthUniversity of SydneyCharles Perkins Centre(D17)SydneyNSWAustralia

Roof plate secretion of bone morphogenetic proteins(BMPs)directs the cellular fate of sensory neurons during spinal cord development,including the formation of the ascending sensory columns,though their biology is not well ***-ⅡBMP receptor(BMPRⅡ),the cognate receptor,is expressed by neural precursor cells during embryogenesis;however,an in vitro method of enriching BMPRⅡ^(+)human neural precursor cells(hNPCs)from the fetal spinal cord is *** was undertaken on intact second-trimester human fetal spinal cord using antibodies to BMPRⅡand leukemia inhibitory factor(LIF).Regions of highest BMPRⅡ^(+)immunofluorescence localized to sensory *** and meningeal-associated BMPRⅡ^(+)vascular cells were identified in both intact fetal spinal cord and cortex by co-positivity with vascular lineage markers,CD34/*** immunostaining identified a population of somas concentrated in dorsal and ventral horn interneurons,mirroring the expression of LIF receptor/CD118.A combination of LIF supplementation and high-density culture maintained culture growth beyond 10 passages,while synergistically increasing the proportion of neurospheres with a stratified,*** neurospheres were characterized by BMPRⅡ^(+)/MAP2ab^(+/–)/βⅢ-tubulin^(+)/nestin^(–)/vimentin^(–)/GFAP^(–)/NeuN^(–)surface hNPCs surrounding a heterogeneous core ofβⅢ-tubulin^(+)/nestin^(+)/vimentin^(+)/GFAP^(+)/MAP2ab^(–)/NeuN^(–)multipotent *** cultures from tripotential neurospheres contained neuronal(βⅢ-tubulin^(+)),astrocytic(GFAP+),and oligodendrocytic(O4+)lineage ***-activated cell sorting-sorted BMPRⅡ^(+)hNPCs were MAP2ab^(+/–)/βⅢ-tubulin^(+)/GFAP^(–)/O4^(–)in *** is the first isolation of BMPRⅡ^(+)hNPCs identified and characterized in human fetal spinal *** data show that LIF combines synergistically with high-density reaggregate cultures to support the organotypic reorganization of neurospheres,characterize

关键词： BMPRⅡ bone morphogenetic protein histotypic human spinal cord development leukemia inhibitory factor neurosphere organotypic reaggregate sensory columns

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X-射线荧光分析硅酸盐岩石的最佳精确度和准确度

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世界地质 1987年第2期 205-215页

作者： bower nathan w. 姜桂兰

作者用理学3064型谱仪测量了10个地球化学参考样品中的十种主要元素和12种痕量元素.确定了X-射线荧光测量的精确度.本文介绍一种采用新方程式评价影响分析精确度和准确度来源的完善方法.测量数据表明,对于许多次测量,要得到最小的分析误... 详细信息

作者用理学3064型谱仪测量了10个地球化学参考样品中的十种主要元素和12种痕量元素.确定了X-射线荧光测量的精确度.本文介绍一种采用新方程式评价影响分析精确度和准确度来源的完善方法.测量数据表明,对于许多次测量,要得到最小的分析误差(RSD为1％)计数时间一分钟为宜.同时,分析时间受样品制备误差的限制,延长分析时间其精确度反而变差.

关键词：参考样品分析时间精度误差来源硅酸盐岩石样品制备基体校正射线荧光分析助熔剂媒熔剂分析者计数时间

Informatic analysis reveals Legionella as a source of novel natural products

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Synthetic and Systems Biotechnology 2016年第2期1卷 130-136页

作者： Chad w.Johnston Jonathan Plumb Xiang Li Sergio Grinstein nathan A.Magarvey The Michael G.DeGroote Institute for Infectious Disease Research Department of Biochemistry and Biomedical SciencesMcMaster UniversityHamiltonONCanada L8N 3Z5 Department of Chemistry and Chemical Biology McMaster UniversityHamiltonONCanada L8N 3Z5 Cell Biology Program Hospital for Sick ChildrenTorontoOntarioCanada M5G 1X8

Microbial natural products are a crucial source of bioactive molecules and unique chemical *** their importance,rediscovery of known natural products from established productive microbes has led to declining interest,even while emergent genomic data suggest that the majority of microbial natural products remain to be ***,new sources of microbial natural products must be defined in order to provide chemical scaffolds for the next generation of small molecules for therapeutic,agricultural,and industrial *** this work,we use specialized bioinformatic programs,genetic knockouts,and comparative metabolomics to define the genus Legionella as a new source of novel natural *** show that Legionella *** a diverse collection of biosynthetic gene clusters for the production of polyketide and nonribosomal peptide natural *** confirm this bioinformatic survey,we create targeted mutants of *** and use comparative metabolomics to identify a novel polyketide *** spectroscopic techniques,we show that this polyketide possesses a new chemical scaffold,and firmly demonstrate that this unexplored genus is a source for novel natural products.

关键词： Natural products Legionella Polyketides PRISM

Reconstructing evolutionary timescales using phylogenomics

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Zoological Systematics 2016年第4期41卷 343-351页

作者： K.Jun Tong nathan Lo Simon Y.w.Ho School of Life and Environmental Sciences University of Sydney

Reconstructing the timescale of the Tree of Life is one of the principal aims of evolutionary biology. This has been greatly aided by the development of the molecular clock, which enables evolutionary timescales to be estimated from genetic data. In recent years, high-throughput sequencing technology has led to an increase in the feasibility and availability ofgenome-scale data sets. These represent a rich source of biological information, but they also bring a set of analytical challenges. In this review, we provide an overview of phylogenomic dating and describe the challenges associated with analysing genome-scale data. we also report on recent phylogenomic estimates of the evolutionary timescales of mammals, birds, and insects.

关键词： Molecular clock phylogenetic analysis genomes rate variation placentalmammals birds insects.

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E-DNA scaffold sensors and the reagentless, single- step, measurement of HIV-diagnostic antibodies in human serum

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Microsystems & Nanoengineering 2020年第1期6卷 1141-1148页

作者： Claudio Parolo Ava S.Greenwood nathan E.Ogden Di Kang Chase Hawes Gabriel Ortega Netzahualcoyotl Arroyo-Curras Kevin w.Plaxco Department of Chemistry and Biochemistry University of CaliforniaSanta BarbaraSanta BarbaraCAUSA Department of Materials University of CaliforniaSanta BarbaraSanta BarbaraCAUSA Department of Pharmacology and Molecular Sciences Johns Hopkins School of MedicineBaltimoreMD 21205USA Interdepartmental Program in Biomolecular Science and Engineering University of CaliforniaSanta BarbaraSanta BarbaraCA 93106USA

The multiplexed,point-of-care measurement of specific antibodies could improve the speed with which diseases are diagnosed and their treatment *** this end,we are developing E-DNA scaffold sensors,which consist of a rigid,nucleic acid“scaffold”attached on one end to an electrode and presenting both a redox reporter and an epitope on the *** the absence of antibody,the reporter efficiently transfers electrons when interrogated ***-induced steric hindrance limits movement,reducing electron transfer in a manner that is both easily measured and quantitatively related to target *** we have used monoclonal antibodies to explore the analytical performance of E-DNA sensors,showing that they support the rapid,single-step,quantitative detection of multiple antibodies in small volume ***,in contrast,we employ authentic human samples to better explore the platform’s clinical ***,we developed E-DNA sensors targeting three HIV-specific antibodies and then compared the analytical and clinical performance of these against those of gold standard serological *** so we find that,although the multistep amplification of an ELISA leads to a lower detection limits,the clinical sensitivity of ELISAs,E-DNA sensors and lateral-flow dipsticks are indistinguishable across our test *** thus appears that,by merging the quantitation and multiplexing of ELISAs with the convenience and speed of dipsticks,E-DNA scaffold sensors could significantly improve on current serological practice.

关键词： antibodies attached initiated

Is There an Association between Bacterial Vaginosis Infection and HIV-1 Infection Acquisition among women Aged 18 - 35 Years in Soweto?

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Open Journal of Preventive Medicine 2016年第9期6卷 197-213页

作者： nathan B. w. Chimbatata School of Public Health Witwatersrand University Johannesburg South Africa Mzuzu University Mzuzu Malawi

Background: Studies suggest that there is association between Bacterial Vaginosis and Human Immunodeficiency Virus infection but its temporal effect has not been sufficiently investigated. Methods: It is a secondary data analysis following a cohort study. It was carried out to describe Bacterial Vaginosis infection association to Human Immunodeficiency Virus acquisition. The primary cohort study registered 750 study participants. A gram stain slide prepared from a vaginal swab was used to measure Bacterial Vaginosis as the primary exposure. A score of 7 or above was considered positive for Bacterial Vaginosis. The determination of the dependent variable Human Immunodeficiency Virus infection was achieved through dual rapid tests which were confirmed by using a third generation ELISA. Incident Human Immunodeficiency Virus infection rate was calculated. To test significance, Kaplan Meier survival time analysis and log rank test were carried out. The association of Bacterial Vaginosis with Human Immunodeficiency Virus infection was investigated using Cox regression. Results: The baseline prevalence of Bacterial Vaginosis was 52%, 95% CI;45 - 59. There were 21 Human Immunodeficiency Virus seroconversions in total of which 7 had no Bacterial Vaginosis results and were left out in the analysis. The analysis only involved 14 seroconversions and these were followed for a mean time of 0.40 of a year and total time at risk of 286 person years. This shows incident rate of Human Immunodeficiency Virus infection of 4.9 per 100 person years of follow up, 95 % CI: 2.9 - 8.27. Kaplan Meier curves revealed a higher risk of incident infection among women who were Bacterial Vaginosis positive than the women who were Bacterial Vaginosis negative. A log rank test showed that the probability of incident infection differed among the women depending on Bacterial Vaginosis status, X2 value 3.8, p value 0.05. Adjusting for the other variables, incident Human Immunodeficiency Virus infection

关键词： Bacterial Vaginosis Human Immunodeficiency Virus Infection women Soweto South Africa

Illness Narrative: Perceptions and Lived Experiences of Kidney Recipient Clients in Shanghai, China

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Open Journal of Nephrology 2016年第3期6卷 67-77页

作者： nathan B. w. Chimbatata Chao Hu School of Public Health Fudan University Shanghai China Mzuzu University Mzuzu Malawi Department of Urology Fudan University Shanghai China

Terminal kidney disease is a life threatening condition and cause for loss of hope to affected individuals. It affects the individuals physically as well as mentally. The advancement in medical knowledge and technology in transplant surgery has steadily increased the number of kidney recipients. This offers hope for the new lease of life and a wide range of perceptions and experiences with self, society and the new organ. There is minimal research on perceptions and lived experiences of kidney transplant recipients. This study explored the perceptions and lived experiences of individuals with a kidney problem living with a kidney transplant in Shanghai, China. Five in-depth interviews were conducted with five clients. The participant’s age ranged from 25 to 45 years. There were three females and two males. Content analysis using NVivo (11.0) software was applied in data analysis. The findings revealed improved quality of life among kidney recipients;however the clients had low knowledge levels on the condition as well as self care practices in the post transplant period. This caused a lot of psychosocial stress in the clients. The post kidney transplant management strategies should include effective education programs to increase awareness on the condition and self care practices so as to reduce factors associated with psychosocial stress in order to improve the quality of life for the clients in the post kidney transplantation period.

关键词： Kidney Transplant Psychosocial Stress Perceptions Lived Experiences Shanghai China

Oxygen Electrocatalysis on Mixed-Metal Oxides/Oxyhydroxides:From Fundamentals to Membrane Electrolyzer Technology

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Accounts of Materials Research 2021年第7期2卷 548-558页

作者： Raina A.Krivina Yingqing Ou Qiucheng Xu Liam P.Twight T.nathan Stovall Shannon w.Boettcher Department of Chemistry and Biochemistry and the Oregon Center for Electrochemistry University of OregonEugeneOregon 97403United States College of Chemistry and Chemical Engineering Chongqing UniversityChongqingChina Department of Materials Science East China University of Science and TechnologyShanghaiChina

CONSPECTUS:Catalyzing the oxygen evolution reaction(OER)is important for key energy-storage technologies,particularly water electrolysis and photoelectrolysis for hydrogen fuel *** neutral-to-alkaline conditions,first-row transitionmetal oxides/(oxy)hydroxides are the fastest-known OER catalysts and have been the subject of intense study for the past *** to their high performance is the intentional or accidental addition of Fe to Ni/Co oxides that convert to layered(oxy)hydroxide structures during the *** the role that Fe plays in the catalysis and the molecular identity of the true“active site”has proved challenging,however,due to the dynamics of the host structure and absorbed Fe sites as well as the diversity of local structures in these disordered active *** this Account,we highlight our work to understand the role of Fe in Ni/Co(oxy)hydroxide OER *** first discuss how we characterize the intrinsic activity of the first-row transition-metal(oxy)hydroxide catalysts as thin films by accounting for the contributions of the catalyst-layer thickness(mass loading)and electrical conductivity as well as the underlying substrate’s chemical interactions with the catalyst and the presence of Fe species in the *** show how Fe-doped Ni/Co(oxy)hydroxides restructure during catalysis,absorb/desorb Fe,and in some cases degrade or regenerate their activity during electrochemical *** highlight the relevant techniques and procedures that allowed us to better understand the role of Fe in activating other first-row transition metals for *** find several modes of Fe incorporation in Ni/Co(oxy)hydroxides and show how those modes correlate with activity and *** also discuss how this understanding informs the incorporation of earthabundant transition-metal OER catalysts in anion-exchange-membrane water electrolyzers(AEMwE)that provide a locally basic anode environment but run on pure water and have advan

关键词： hydroxide catalyst catalysis