摘要：Fast electron-hole recombination issues during titanium dioxide(TiO_(2))photocatalysis limit its application in preventing bacterial infection during bone defect *** this study,TiO_(2)@reduced graphene oxide(rGO)composites were synthesized using a hydrothermal method in which rGO,which possesses very high electrical conductivity,promotes the separation of photoelectron-hole pairs of TiO_(2),thus improving the efficiency of photocatalytic production of reactive oxygen species(ROS).Subsequently,TiO_(2)@rGO composites were introduced into poly-L-lactic acid(PLLA)to prepare bone scaffolds with photocatalytic antibacterial function via selective laser *** results showed that TiO_(2)grew on the surface of rGO and formed a covalent bond connection(Ti-O-C)with rGO.A decreased electrochemical impedance of TiO_(2)@rGO composites was observed,and the transient photocurrent intensity increased from 0.05 to 0.5μA/cm^(2).Analysis of electron spin resonance found that the photocatalytic products of TiO_(2)were·OH and·O^(2-),two kinds of ROS capable of killing bacteria via disrupting the structure of the bacterial membrane in *** experiments showed that the PLLA/TiO_(2)@rGO scaffolds had good antibacterial properties against Escherichia coli and Staphylococcus ***,we report that these scaffolds exhibited both enhanced mechanical properties due to the addition of TiO_(2)@rGO as a reinforcement material and good biocompatibility during cell proliferation.

摘要：Fuel cells have attracted extensive attention due to their high conversion efficiency and environmental ***,their wider application is limited by the poor activity and high cost of platinum(Pt),which is widely used as the cathode catalyst to overcome the slow kinetics associated with oxygen reduction reaction(ORR).Pt‐based composites with one‐dimensional(1D)nanoarchitectures demonstrate great advantages towards efficient ORR *** review focuses on the recent advancements in the design and synthesis of 1D Pt‐based ORR *** introducing the fundamental ORR mechanism and the advanced 1D architectures,their synthesis strategies(template‐based and template‐free methods)are ***,their morphology and structure optimization are highlighted,followed by the superstructure assembly using 1D Pt‐based ***,the challenges and perspectives on the synthesis innovation,structure design,physical characterization,and theoretical investigations are proposed for 1D Pt‐based ORR *** anticipate this study will inspire more research endeavors on efficient ORR nanocatalysts in fuel cell application.

摘要：*** Power and sample size estimation constitutes an important component of designing and planning modern scientific *** provides information for assessing the feasibility of a study to detect treatment effects and for estimating the resources needed to conduct the *** tutorial discusses the basic concepts of power analysis and the major differences between hypothesis testing and power *** also

摘要：地点:某年末平均人口为9084 名囚犯的监狱系统。目的:确定在一个较长时期内的结核病传播动力学;确定该结核杆菌株是否为监狱系统中结核病流行的主要原因;确定社区病例分离株的成簇性是否和监狱系统有联系。设计:对过去9 年中监狱系统报告的结核病例进行回顾性流行病学分析。另外,将囚犯结核杆菌分离株的IS6110-RFLP 图谱与其它病例进行总体比较。将RFLP 分析结果与流行病学调查结果进行对照。结果:监狱系统中约80%的病例分离株成簇。在过去的9 年中50%以上病例属同一结核杆菌株。社区内由同一株结核杆菌引起的病例与监狱系统存在明显关联。结论:虽然已实行了强有力的结核病控制措施,但是某结核杆菌株仍在监狱系统持续流行。在被诊断和治疗之前,其持留性可使潜伏感染复燃,并感染其他患者,从而使传播链持续下去。

摘要：背景:超过生理需要的铁聚集可通过增强铁催化、自由基介导的氧化应激而导致心血管疾病风险增高。目的:在一组有症状性外周动脉疾病(PAD)患者中验证静脉切开降低机体铁储备可影响患者临床结局的假说。设计、机构和患者:基于铁(Fe)和动脉粥样硬化研究(FeAST)(VA合作研究#410)进行一项多中心、随机、对照、单盲性临床试验,该试验于1999年5月1日至2005年4月30日实施,属于退伍军人事务部合作研究项目,共纳入1277例有症状但病情稳定的PAD患者。

摘要：Developing efficient platinum(Pt)-based electrocatalysts is enormously significant for fuel ***,we report an integrated electrocatalyst of ultralow-Pt alloy encapsulated into nitrogen-doped nanocarbon architecture for efficient oxygen reduction *** hybrid Pt-based catalyst achieves a mass activity of 3.46 A mg^(-1)_(pt)the potential of 0.9 V *** with a negligible stability decay after 10,000 *** importantly,this half-cell activity can be expressed at full cell level with a high Pt utilization of 10.22 W mg^(-1)_(Pt cathode)and remarkable durability after 30,000 cycles in *** and theoretical investigations reveal that a highly strained Pt structure with an optimal Pt-0 binding energy is induced by the incorporation of Co/Ni into Pt lattice,which would account for the improved reaction *** synergistic catalysis due to nitrogen-doped nanocarbon architecture and active Pt component is responsible for the enhanced catalytic ***,the strong metal-support interaction and optimized hydrophilic properties of nanocarbon matrix facilitate efficient mass transport and water *** work may provide significant insights in designing the low-Pt integrated electrocatalysts for fuel cells and beyond.

摘要：背景：接受非心脏手术的老年患者出现红细胞压积异常和心血管并发症的危险较高。尽管患者术前几乎都要进行红细胞压积筛查，但是有关术前贫血及红细胞增多症的不良影响的证据较为有限。目的：于实施非心脏大手术的退伍老兵中评估术前贫血和红细胞增多症的发生率及其对术后30天预后的影响。设计：利用全国退伍军人事务委员会（VA）于术质量改进计划数据库进行回顾性队列研究。根据术前红细胞压积水平将患者分为三类：贫血（红细胞压积〈39．0％）、正常（红细胞压积39．0％～53．9％）和红细胞增多症（红细胞压积≥54％）。对红细胞压积异常与术后30天心血管事件发生率及死亡率的关系进行评估。地点及患者：纳入1997至2004年于全美132个退伍军人医疗中心接受非心脏大手术的310311例患者（年龄≥65岁）。主要观测指标：主要观测指标为术后30天死亡率，次要观测指标包括术后30天死亡率或心脏事件（心脏骤停或Q波心肌梗死）发生率。结果：与红细胞压积正常者相比，红细胞压积发生正向或负向偏离者术后30天死亡率和心脏事件发生率均有所增加。研究发现，红细胞压积水平较正常范围每增减1个百分点，术后30天死亡率就可增加1．6％（95％可信区间，1．1％-2．2％）。进一步分析显示，当红细胞压积降至39％以下或超过51％时，校正后30天死亡风险和心脏病患病风险就开始增加。结论：接受非心脏大手术的老年患者（绝大多数为男性退伍军人）术前轻度贫血及红细胞增多症均可增加术后发生死亡和心脏事件的危险。今后的研究应明确上述发现可否见于其他人群，明确术前纠正贫血和红细胞增多症能否降低术后死亡风险。

摘要：目的 比较子宫颈癌筛查中传统子宫颈涂片、单层细胞学,以及人乳头状瘤病毒检测的敏感性、特异性和观察者间的可信性。 设计 对同时进行了此3项检查并有参考标准(阴道镜和组织学)者进行横断面研究。 研究单位 法国的公立大学和私人诊所,本研究完全独立于病例提供者。 研究对象 因先前检出的细胞学异常而进行阴道镜检查的828名妇女和参加常规涂片检查的1757名妇女。 主要结果判定指标 临床读片和最优化解释(为取得一致所进行的双盲读片)。根据诊断异常的不同阈值计算出敏感性、特异性和加权κ值。 结果 根据Bethesda系统,传统子宫颈涂片检查得到的结果更为满意(91％比87％),比单层细胞学更可靠(加权κ值0.70比0.57),其敏感性和特异性更高。这些结果适用于临床读片和最优化解释,区分高级别和低级别病变,以及有低和高异常发生率的人群。人乳头状瘤病毒检测与单层细胞学检查同时进行,不论是系统性的还是只对于意义不明的非典型细胞,并不比传统涂片检查优越。 结论 在子宫颈癌筛选中,单层细胞学检查不如传统子宫颈涂片检查可靠,且更容易出现假阳性和假阴性结果。

摘要：本针刺随机对照试验(Randomised controlled trials, RCT)专家共识是基于目前针刺试验面临的最普遍、最关键问题,由临床医生、研究人员、从事针灸和外科的临床试验专家、统计专家、临床流行病学和方法学专家以及患者组成的国际临床研究小组联合制订。该共识将有助于临床试验资助者、注册者以及期刊编辑等评估针刺RCT方案及研究结果的相关性、重要性和质量。