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Tribological behavior of lubricant-impregnated porous polyimide

Friction 2024年第4期12卷 711-725页

作者： Jinbang LI Ningning ZHOU janet S.S.WONG School of Mechanical Engineering and Mechanics Ningbo UniversityNingbo 315211China Beijing Key Laboratory of Long-life Technology of Precise Rotation and Transmission Mechanisms Beijing Institute of Control EngineeringBeijing 100029China Department of Mechanical Engineering Imperial College LondonLondon SW72AZUK

Porous materials impregnated with lubricants can be used in conditions where limited lubricant is desirable.In this work,three porous polyimides(PPI)with different densities were prepared.Polyalphaolefin(PAO)impregnated PPI(iPPI)discs were rubbed against steel and sapphire balls.In operando observations of the iPPI-sapphire contacts show that oil is released under an applied load,forming a meniscus around contacts.Cavitation at the outlet is created at high sliding speeds.The amount of released oil increases with increasing PPI porosity.Contact moduli,E*,estimated based on the actual contact size show that trapped oil in iPPIs contributes to load support.At higher speeds,tribological rehydration of the contact occurs in low density iPPI,with that E*rises with speed.For high density PPIs,high speeds give a constantly high E*which is limited by the viscoelastic properties of the PPI network and possibly the rate of oil exudation.Friction of iPPI-steel contacts is governed by the mechanical properties of the PPI,the flow of the lubricant,and the roughness of the PPI surfaces.For low-and medium-density(highly porous,high roughness)PPIs,large amount of oil is released,and lubrication is mainly via lubricant restricted in the contact in the pores and possibly tribological rehydration.For high density(low porosity)PPI,with lower roughness,hydrodynamic lubrication is achieved which gives the lowest friction.Our results show that polymeric porous materials for effective lubrication require the optimization of its surface roughness,stiffness,oil flow,and oil retentions.

关键词： polyimide porous material friction mechanism polymer limited lubrication

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A Vertex Network Model of Arabidopsis Leaf Growth

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Communications on Applied Mathematics and Computation 2024年第1期6卷 454-488页

作者： Luke Andrejek janet Best Ching-Shan Chou Aman Husbands Department of Mathematics The Ohio State UniversityColumbusOHUSA Department of Biology The University of PennsylvaniaPhiladelphiaPAUSA

Biology provides many examples of complex systems whose properties allow organisms to develop in a highly reproducible,or robust,manner.One such system is the growth and development of flat leaves in Arabidopsis thaliana.This mechanistically challenging process results from multiple inputs including gene interactions,cellular geometry,growth rates,and coordinated cell divisions.To better understand how this complex genetic and cellular information controls leaf growth,we developed a mathematical model of flat leaf production.This two-dimensional model describes the gene interactions in a vertex network of cells which grow and divide according to physical forces and genetic information.Interestingly,the model predicts the presence of an unknown additional factor required for the formation of biologically realistic gene expression domains and iterative cell division.This two-dimensional model will form the basis for future studies into robustness of adaxial-abaxial patterning.

关键词： Robustness Adaxial-abaxial patterning Mathematical modeling Gene regulatory networks(GRNs) Transcription factors Small RNAs

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Limb Lengthening and Reconstruction Society orthopedic surgeons in the United States:An analysis of geographical distribution,academic,leadership,and demographic characteristics

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World Journal of Orthopedics 2024年第2期15卷 147-155页

作者： Amir Human Hoveidaei Reza Niakan Seyed Hossein Hosseini-Asl Abijith Annasamudram janet D Conway International Center for Limb Lengthening Rubin Institute for Advanced OrthopedicsSinai Hospital of BaltimoreBaltimoreMD 21215United States Student Research Committee Shiraz University of Medical SciencesShiraz 73Iran Students’Scientific Research Center Tehran University of Medical SciencesTehran ***Iran

BACKGROUND The Limb Lengthening and Reconstruction Society(LLRS)is a premier orthopedic specialty organization that promotes limb reconstruction for all ages.LLRS membership characteristics,however,are poorly reported.This study delineates orthopedic surgeon LLRS members’demographic traits,academic achievement,leadership attainment,and geographical distribution across the United States.AIM To inform aspiring orthopedic professionals,as well as to promote growth and diversity in both the LLRS organization and overarching field.METHODS This cross-sectional study examined United States LLRS members’academic,leadership,demographic,and geographical attributes.After reviewing the 2023 LLRS member directory,Google search results were matched to the listings and appended to the compiled data.Sex and ethnicity were evaluated visually utilizing retrieved images.The Hirsch index(H-index)of academic activity,residency and fellowship training,other graduate degrees,leadership positions,practice type(academic or non-academic),and spoken languages were categorized.LLRS members per state and capita determined geographic distribution.The Mann Whitney U test was applied to compare H-index between males and females,as well as to assess member differences pertaining to affiliation with academic vs non-academic practice facilities.RESULTS The study included 101 orthopedic surgeons,78(77.23%)Caucasian and 23(22.77%)non-Caucasian,79(78.22%)male and 22(21.78%)female.Surgeons with DO degrees comprised only 3.96%(4)of the cohort,while the vast majority held MDs[96.04%(97)].Mean H-index was 10.55,with male surgeons having a significantly higher score(P=0.002).Most orthopedic surgeons(88.12%,)practiced in academic centers.Of those professionals who occupied leadership positions,14%were women,while 86%were men.Additionally,19(37.25%)United States regions and the District of Columbia lacked an LLRS-member orthopedic surgeon.Total per capita rate across the United States was 0.30 LLRS orthopedic surgeons per 1 million people.CONCLUSION Over 21

关键词： Limb lengthening and reconstruction Orthopedic surgeon demographics Orthopedic surgeon societal membership Orthopedic fellowships

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流水车间加工信息测度与控制

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中国科学：技术科学 2024年第6期54卷 1091-1104页

作者：张志峰 janet David 刘俊桂林航天工业学院管理学院桂林541004 Department of Engineering Science University of OxfordOxford OX13PJUK 华中科技大学机械科学与工程学院武汉430074

流水车间加工信息的有效测度是实施加工批量决策的前提.当前多品种小批量生产信息控制研究多以生产技术、范式及智能算法等理论优化工作为主,极少开展生产的加工批量与其状态控制所需信息之间关系的研究,导致研究结论过于理论化而难以... 详细信息

流水车间加工信息的有效测度是实施加工批量决策的前提.当前多品种小批量生产信息控制研究多以生产技术、范式及智能算法等理论优化工作为主,极少开展生产的加工批量与其状态控制所需信息之间关系的研究,导致研究结论过于理论化而难以应用于现实生产.针对此研究局限性,本文从信息论角度出发,根据制造马尔科夫过程,定义流水车间的加工批量信息熵并解析其度量特性.进一步,构建流水车间加工批量信息熵函数,理论上证明其函数单调递减性.通过建立流水车间加工批次信息测度模型,确定生产线批次加工信息的组成结构,实现对工件加工所需信息量的测度.实证研究中,将平均调整准备时间、平均加工时间及完工时间等观测数据应用于实际企业的减速器生产线,做出不同参量与加工批量变化关系图,确定相关参数条件下生产线的最优加工批量.根据研究结果,提出有效减少管理与控制生产线所需信息量的对策,在验证所建熵模型科学性与有效性的同时,也为实际生产中的批量决策提供准确的现实指导.

关键词：流水车间加工批量熵函数信息测度

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锌转运体8自身抗体对急性起病糖尿病患者分型诊断的价值

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中华医学杂志 2010年第36期90卷 2536-2540页

作者：杨琳罗说明黄干彭健颜湘 janet wenzlau Howard W Davidson John C Hutton 周智广中南大学湘雅二医院内分泌科中南大学代谢内分泌研究所中南大学糖尿病中心长沙410011 PO Box 6511 1775 Ursul a Court Aurora CO 80045 Barbara Davis Center for Childhood Diabetes University of Colorado at Denver and Health Sciences Center USA

目的探讨锌转运体8自身抗体（ZnT8A）对急性起病糖尿病患者分型诊断的价值.方法 453例急性起病糖尿病患者根据谷氨酸脱羧酶抗体（GADA）和酪氨酸磷酸酶抗体（IA2-A）阳性分为A＋组276例（任一抗体阳性）和A-组177例（抗体皆为阴性）将... 详细信息

目的探讨锌转运体8自身抗体（ZnT8A）对急性起病糖尿病患者分型诊断的价值.方法 453例急性起病糖尿病患者根据谷氨酸脱羧酶抗体（GADA）和酪氨酸磷酸酶抗体（IA2-A）阳性分为A＋组276例（任一抗体阳性）和A-组177例（抗体皆为阴性）将555例2型糖尿病患者和405名健康者作为对照.分析ZnT8A在急性起病糖尿病患者和亚组中的分布规律、相关因素和ZnT8A阳性者的临床特征.抗体检测采用放射配体法.结果（1）ZnT8A在急性起病糖尿病组的阳性率为24.3%,显著高于2型糖尿病组（1.8%）和健康对照组（1.0%）（均P＜0.01）而且ZnT8A在A＋组中的检出率为29.7%,显著高于A-组患者15.8%（x2=11.318,P＜0.01）.（2）ZnT8A阳性率在＜30岁各亚组高于≥30岁亚组（0～9岁,34.9% 10～19岁,26.7% 20～29岁,26.3%比≥30岁,18.3% 均P＜0.05）在体质指数（BMI）＜21.0 kg/m2和21.0～25.0 kg/m2亚组高于BMI＞25.0 kg/m2亚组（25.5%和25.9%比8.7%,均P＜0.05）.（3）ZnT8A水平与IA2-A滴度间呈正相关（r=0.165,P=0.01）.（4）3种抗体联合测定使自身免疫检出率从60.9%提高到67.1%.（5）与抗体阴性者相比,ZnT8A单独阳性者日胰岛素需要量较多[（35.5±9.3）U/d比（29.8±14.7）U/d,P＜0.05],而收缩压和舒张压均较低[（107±15）mm Hg比（113±16）mm Hg,（69±12）mm Hg比（73±12）mm Hg,均P＜0.05].结论 ZnT8A对急性起病糖尿病患者的免疫分型诊断有一定价值,在常见抗体（GADA和IA2-A）阴性者中可识别出一类更接近于经典1型糖尿病的临床表型.

关键词：糖尿病,1型诊断 ZnT8自身抗体急性起病

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Hypotension prediction index together with cerebral oxygenation in guiding intraoperative hemodynamic management: a case report

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The Journal of Biomedical Research 2022年第1期36卷 73-77页

作者： Yun Li janet Phan Azaam Mamoor Hong Liu Department of Anesthesiology the Second Hospital of Anhui Medical UniversityHefeiAnhui 230601China Department of Anesthesiology and Pain Medicine University of California Davis HealthSacramentoCA 95817USA California Northstate University College of Medicine SacramentoCA 95757USA

Intraoperative hypotension happens in everyday clinical practice. It was suggested to have a strong association with adverse postoperative outcomes. Hypotension prediction index(HPI) was developed to predict intraoperative hypotension(mean arterial pressure <65 mmHg) in real time. However, pressure autoregulation also plays an important role in maintaining adequate organ perfusion/oxygenation during hypotension. A cerebral oxygenation monitor provides clinicians with the values of organ oxygenation. We reported a case that the cerebral oxygenation monitor was used together with HPI to guide intraoperative blood pressure management. We found that cerebral oxygenation was maintained in the event of hypotension during surgery. The patient had no intraoperative or postoperative adverse outcomes despite the hypotension. We believe this can provide an individualized intraoperative blood pressure management to avoid over-or under-treating hypotension.

关键词： hypotension prediction index cerebral oxygenation hemodynamic intraoperative

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Status of precision medicine approaches to traumatic brain injury

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Neural Regeneration Research 2022年第10期17卷 2166-2171页

作者： Sahithi Reddi Smita Thakker-Varia janet Alder Anna O.Giarratana Department of Neuroscience and Cell Biology Rutgers Robert Wood Johnson Medical SchoolPiscatawayNJUSA

Traumatic brain injury(TBI)is a serious condition in which trauma to the head causes damage to the brain,leading to a disruption in brain function.This is a significant health issue worldwide,with around 69 million people suffering from TBI each year.Immediately following the trauma,damage occurs in the acute phase of injury that leads to the primary outcomes of the TBI.In the hours-to-days that follow,secondary damage can also occur,leading to chronic outcomes.TBIs can range in severity from mild to severe,and can be complicated by the fact that some individuals sustain multiple TBIs,a risk factor for worse long-term outcomes.Although our knowledge about the pathophysiology of TBI has increased in recent years,unfortunately this has not been translated into effective clinical therapies.The U.S.Food and Drug Administration has yet to approve any drugs for the treatment of TBI;current clinical treatment guidelines merely offer supportive care.Outcomes between individuals greatly vary,which makes the treatment for TBI so challenging.A blow of similar force can have only mild,primary outcomes in one individual and yet cause severe,chronic outcomes in another.One of the reasons that have been proposed for this differential response to TBI is the underlying genetic differences across the population.Due to this,many researchers have begun to investigate the possibility of using precision medicine techniques to address TBI treatment.In this review,we will discuss the research detailing the identification of genetic risk factors for worse outcomes after TBI,and the work investigating personalized treatments for these higher-risk individuals.We highlight the need for further research into the identification of higher-risk individuals and the development of personalized therapies for TBI.

关键词： apolipoprotein E biomarkers brain injury brain-derived neurotrophic factor clinical trials personalized treatments precision medicine tau translational research traumatic brain injury

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Towards high strength cast Mg-RE based alloys:Phase diagrams and strengthening mechanisms

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Journal of Magnesium and Alloys 2022年第6期10卷 1401-1427页

作者： janet M.Meier Josh Caris Alan A.Luo Department of Materials Science and Engineering The Ohio State UniversityColumbusOH 43210USA Terves LLC EuclidOH 44117USA Department of Integrated Systems Engineering The Ohio State UniversityColumbusOH 43210USA

Mg-rare earth(RE)based systems provide several important commercial alloys and many alloy development opportunities for high strength applications,especially in aerospace and defense industries.The phase diagrams,microstructure,and strengthening mechanisms of these multicomponent systems are very complex and often not well understood in literature.We have calculated phase diagrams of important binary,ternary,and multicomponent RE-containing alloy systems,using CALPHAD(CALculation of PHAse Diagrams).Based on these phase diagrams,this paper offers a critical overview on phase equilibria and strengthening mechanisms in these alloy systems,including precipitation,long period stacking order(LPSO),and other intermetallic phases.This review also summarized several promising Mg-RE based cast alloys in comparison with commercial WE54 and WE43 alloys;and explored new strategies for future alloy development for high strength applications.It is pointed out that the combination of precipitation and LPSO phases can lead to superior strength and ductility in Mg-RE based cast alloys.The precipitates and LPSO phases can form a complex three-dimensional network that effectively impedes dislocation motion on the basal and non-basal planes.The LPSO phases can also prevent the coarsening of precipitates when they interact,thus providing good thermal stability at elevated temperatures.Future research is needed to determine how the combination of these two types of phases can be used in alloy design and industrial scale applications.

关键词： Magnesium alloys Phase diagrams Precipitation strengthening Long period stacking order(LPSO) Alloy development CALPHAD

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Role of locoregional therapies in the management of patients with hepatocellular carcinoma

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Hepatoma Research 2022年第1期8卷 106-126页

作者： janet Wui Cheung Kung Kelvin Kwok Chai Ng Department of Surgery The Chinese University of Hong KongHong Kong 999077China

Hepatocellular carcinoma(HCC)was the sixth most common cancer and the third cause of cancer-related deaths worldwide in 2020.Liver resection and transplantation remain the cornerstone for patients with early-stage disease and represent the only option for potential cure in HCC.However,fewer than 10%of patients are considered suitable for surgery at the time of diagnosis.Locoregional therapies,defined as minimally invasive image-guided liver tumour-directed procedures,are integral to in the management of HCC.This review discusses the role of locoregional therapies in HCC management in the emergence of immune and systemic treatments.

关键词： Locoregional therapy hepatocellular carcinoma ablation transarterial embolization radiation therapy

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The"weekend effect"does not impact on outcome of trauma laparotomy–Experience from a level 1 trauma centre in New Zealand

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中华创伤杂志：英文版 2023年第2期26卷 73-76页

作者： Jonathan Ko Victor Kong janet Amey Damien Ah Yen Damian Clarke Grant Christey Department of Surgery University of AucklandAucklandNew Zealand Department of Trauma Waikato HospitalHamiltonNew Zealand Department of Surgery University of the WitwatersrandJohannesburgSouth Africa Te Manawa Taki Trauma System WaikatoNew Zealand

Purpose:Trauma centres have been proven to provide better outcomes in developed countries for overall trauma,but there is limited literature on the systematic factors that describe any discrepancies in outcomes for trauma laparotomies in these centres.This study was conducted to examine and interrogate the effect of systematic factors on patients undergoing a trauma laparotomy in a developed country,intending to identify potential discrepancies in the outcome.Methods:This was a retrospective study of all laparotomies performed for trauma at a level 1 trauma centre in New Zealand.All adult patients who had undergone an index laparotomy for trauma between February 2012 and November 2020 were identified and laparotomies for both blunt and penetrating trauma were included.Repeat laparotomies and trauma laparotomies in children were excluded.The primary clinical outcomes reviewed included morbidity,length of hospital stay,and mortality.All statistical analysis was performed using R v.4.0.3.Results:During the 9-year study period,204 trauma laparotomies were performed at Waikato hospital.The majority(83.3%)were performed during office hours(170/204),and the remaining 16.7%were performed after hours(34/204).And 61.3%were performed on a weekday(125/204),whilst 38.7%were performed on the weekend/public holiday(79/204).Most of the parameters in office hours and after hours groups had no statistically significant difference,except lactate(p=0.026).Most of the variables in weekday and weekend groups had no statistically significant difference,except pH,lactate,length of stay,and gastrointestinal complications(p=0.012,p<0.001,p=0.003,p=0.020,respectively).Conclusion:The current trauma system at Waikato hospital is capable of delivering care for trauma laparotomy patients with the same outcome regardless of working hours or after hours,weekday or weekend.This confirms the importance of a robust trauma system capable of responding to the sudden demands placed on it.

关键词： Wounds and injuries General surgery Trauma surgery Abdominal trauma Systematic factors

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