Fundamentals

基础知识
  • 文章类型: Journal Article
    由于脉冲洗脱-LC×LC(PE-LC×LC)中第一(1D)和第二(2D)维度的解耦,与快速综合LC×LC相比,方法开发更加灵活和直接,其中两个维度之间的关键参数的依赖性限制了其灵活性。在这项研究中,我们提出了一种脉冲生成方法,这是基于一个切换阀,在一个泵之间交替输送梯度和第二泵,提供低洗脱强度的暂停状态。因此,在流速为0.2和0.4mL/min的情况下,可以规避系统的停留时间,并在编程和观察到的流动相组成之间具有令人满意的精度(相对偏差为6.0%),可以产生7.5和3.75倍的短脉冲宽度。我们研究了包括脉冲宽度和步长在内的关键参数,2D梯度时间和流速影响PE-LC×LC中的峰值容量。将产生PE-LC×LC-高分辨率质谱(HRMS)系统的最高峰容量的条件应用于废水流出物样品。将结果与一维(1D)-LC-HRMS色谱图进行比较。在校正欠采样后,峰值容量从1D-LC运行的112增加到PE-LC×LC-HRMS的3770。PE-LC×LC-HRMS的分析时间为12.1小时,而1D-LC-HRMS的分析时间为67.5分钟。对于低和高碰撞能量迹线,PE-LC×LC-HRMS的质谱纯度提高了2.6倍(p值3.3×10-6)和2.0倍(p值2.5×10-3)与1D-LC-HRMS分析相比。此外,与基于42种鉴定化合物的1D-LC-HRMS分离相比,信噪比(S/N)高4.2倍(范围:0.06-56.7,p值3.8×10-2)。在PE-LC×LC-HRMS中获得的较低的峰体积解释了S/N的改善。
    Due to the decoupling of the first (1D) and second (2D) dimension in pulsed elution-LC × LC (PE-LC × LC), method development is more flexible and straightforward compared to fast comprehensive LC × LC where the dependencies of key parameters between the two dimensions limits its flexibility. In this study we present a method for pulse generation, which is based on a switching valve alternating between one pump that delivers the gradient and a second pump that delivers low eluotrophic strength for the pause state. Consequently, the dwell volume of the system was circumvented and 7.5, and 3.75 times shorter pulse widths could be generated at flow rates of 0.2, and 0.4 mL/min with satisfactory accuracies between programmed and observed mobile phase composition (relative deviation of 6.0 %). We investigated how key parameters including pulse width and step height, 2D gradient time and flow rate affected the peak capacity in PE-LC × LC. The conditions yielding the highest peak capacity for the PE-LC × LC- high-resolution mass spectrometry (HRMS) system were applied to a wastewater effluent sample. The results were compared to a one dimensional (1D)-LC-HRMS chromatogram. The peak capacity increased with a factor 34 from 112 for the 1D-LC run to 3770 for PE-LC × LC-HRMS after correction for undersampling. The analysis time for PE-LC × LC-HRMS was 12.1 h compared to 67.5 min for the 1D-LC-HRMS run. The purity of the mass spectra improved for PE-LC × LC-HRMS by a factor 2.6 (p-value 3.3 × 10-6) and 2.0 (p-value 2.5 × 10-3) for the low and high collision energy trace compared to the 1D-LC-HRMS analysis. Furthermore, the signal-to-noise ratio (S/N) was 4.2 times higher (range: 0.06-56.7, p-value 3.8 × 10-2) compared to the 1D-LC-HRMS separation based on 42 identified compounds. The improvements in S/N were explained by the lower peak volume obtained in the PE-LC × LC-HRMS.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    气体传感器在环境监测中至关重要,工业安全,和医学诊断。由于对精确可靠的气体检测的需求不断增加,对具有卓越灵敏度的尖端气体传感器的需求不断增长,选择性,和稳定性。由于其可调的电性能,高密度表面活性位点,和显著的表面体积比,纳米材料在这方面得到了广泛的研究。传统的气体传感器使用均质材料进行感测,其中吸附的表面氧物种在其感测活动中起着至关重要的作用。然而,它们的选择性气体传感性能仍然不能令人满意,因为所采用的高温导致稳定性差。异质结构纳米材料可以轻松调整传感性能及其不同的能带结构,工作函数,电荷载流子浓度和极性,和界面带对齐可以精确地设计用于低温下的高性能选择性气体传感。在这篇评论文章中,我们详细讨论了半导体气体传感的基本原理及其机理。Further,我们强调了半导体气体传感存在的挑战。此外,我们从不同的角度回顾了半导体气体传感器设计应用的最新进展。最后,最后讨论了改进气体传感性能的结论和未来前景。
    Gas sensors are crucial in environmental monitoring, industrial safety, and medical diagnostics. Due to the rising demand for precise and reliable gas detection, there is a rising demand for cutting-edge gas sensors that possess exceptional sensitivity, selectivity, and stability. Due to their tunable electrical properties, high-density surface-active sites, and significant surface-to-volume ratio, nanomaterials have been extensively investigated in this regard. The traditional gas sensors utilize homogeneous material for sensing where the adsorbed surface oxygen species play a vital role in their sensing activity. However, their performance for selective gas sensing is still unsatisfactory because the employed high temperature leads to the poor stability. The heterostructures nanomaterials can easily tune sensing performance and their different energy band structures, work functions, charge carrier concentration and polarity, and interfacial band alignments can be precisely designed for high-performance selective gas sensing at low temperature. In this review article, we discuss in detail the fundamentals of semiconductor gas sensing along with their mechanisms. Further, we highlight the existed challenges in semiconductor gas sensing. In addition, we review the recent advancements in semiconductor gas sensor design for applications from different perspective. Finally, the conclusion and future perspectives for improvement of the gas sensing performance are discussed.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    自2004年以来,美国胃肠和内窥镜外科医生协会(SAGES)对腹腔镜手术基础(FLS)的实施一直需要在普通外科培训中对腹腔镜技能的教育结构。这项研究着眼于FLS如何影响腹腔镜手术的居民自我效能(SE)。
    我们进行了一项全国调查,与2020年美国外科培训考试委员会(ABSITE)相关,来自325个美国普通外科培训计划的9275名居民参加了该计划。在线调查包括多模式问题,分析参与者是否认为他们可以在居民中执行最常记录的腹腔镜手术[腹腔镜阑尾切除术(LA),腹腔镜胆囊切除术(LC),腹腔镜右半结肠切除术(LRH),诊断腹腔镜检查(DL)]无需教职员工协助。这使用了5点量表评估,范围从“不能够”到“绝对能够”。“多变量分析确定完成FLS对居民自我效能感是否有影响,按研究生年(PGY)分层。
    在调查时,2300报告完成FLS。FLS完成的百分比从PGY1增加到PGY5(4.2%n=59vs85.8%n=893)。完成FLS的PGY1居民,来自48个不同的机构,在LA(p=0.001)和LRH(p=0.012)中,SE的显着增加(p<0.05),感知的自我效能感明显更高。PGY2和PGY3居民表明DL中SE升高(分别为p=0.037,p=0.015),基于FLS完成。这些FLS效应在更高级的班级中不太明显。
    完成FLS可以说对更多的初级居民有最大的好处,因为它建立了腹腔镜知识和技能的基础,可以在此基础上进行进一步的住院医师培训。成功完成腹腔镜手术基础提供的课程和评估,可以提高早期学员的能力。
    Implementation of the Fundamentals of Laparoscopic Surgery (FLS) by the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) has served a need for educational structure for laparoscopic skill within General Surgery training since 2004. This study looks at how FLS affects resident self-efficacy (SE) with laparoscopic procedures.
    We conducted a national survey, linked to the 2020 American Board of Surgery In-Training Examination (ABSITE), in which 9275 residents from 325 US General Surgery Training Programs participated. The online survey included multimodal questions that analyzed whether participants felt they could perform the most commonly-logged laparoscopic operations among residents [Laparoscopic Appendectomy (LA), Laparoscopic Cholecystectomy (LC), Laparoscopic Right Hemicolectomy (LRH), Diagnostic Laparoscopy (DL)] without faculty assistance. This used a 5-point scaled assessment, ranging from \"not able to\" to \"definitely able to.\" Multivariate analyses determined if completion of FLS made a difference for resident self-efficacy, stratified by post-graduate year (PGY).
    At the time of the survey, 2300 reported completion of FLS. The percentage of FLS completion increased from PGY1 to PGY5 (4.2% n = 59 vs 85.8% n = 893). PGY1 residents who completed FLS, from 48 diverse institutions, demonstrated the most significant increases in SE (p < 0.05) with significantly higher perceived self-efficacy in LA (p = 0.001) and LRH (p = 0.012). PGY2 and PGY3 residents indicated increased SE in DL (p = 0.037, p = 0.015, respectively), based on FLS completion. These FLS effects were less evident in the more senior classes.
    Completion of FLS arguably has the greatest benefits for more junior residents, as it establishes a foundation of laparoscopic knowledge and skill, upon which further residency training can build. Successful completion of the curriculum and assessment offered by the Fundamentals of Laparoscopic Surgery leads to greater sense of ability in early trainees.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    背景:美国外科委员会(ABS)自2018年以来一直要求普外科申请人进行内窥镜手术(FES)基础认证。建议在参加FES考试之前完成灵活的内窥镜检查课程(FEC)。研究的目的是确定完成FEC是否使个人能够通过FES手动技能测试。
    方法:参与者包括2014年6月至2019年2月的首次尝试FES考生。对去识别的数据进行了审查,自我报告的数据包括性别,PGY,手套尺寸,上部(UE)和下部(LE)内窥镜检查经验,模拟训练时间,并参与内窥镜检查旋转(ER)。FES技能考试成绩由FES工作人员报告。那些完成所有的vs.没有比较FEC。
    结果:在确定的2023名参与者中,809(40.0%)报告完成了所有FEC组件,1053(52.1%)完成了一些,161名(8.0%)未完成。男性和在居住后期服用FES的候选人更有可能完成所有FEC要求(p=0.002,p<0.001)。完成所有FEC组件的FES通过率高于未完成的人(88.4%vs72.7%,p<0.001)。在逻辑回归分析中,完成所有组件(OR2.3,95%CI1.5-3.7,p<0.001)和男性(OR3.1,95%CI1.7-5.7,p<0.001)是通过的预测因子,而手套尺寸(OR1.5,95%CI1.0-2.5,p=0.08),模拟器时间(OR1.1,95%CI0.9-1.4,p=0.37)和PGY未(OR1.1,95%CI0.9-1.4,p=0.38)。在控制手套尺寸和性别的多变量分析中,完成所有FEC组件仍与通过FES技能考试的可能性较高相关(OR1.6,95%CI1.2-2.1,p<0.001).
    结论:完成FEC与通过FES技能测试密切相关。这项研究支持ABS建议在参加FES技能测试之前完成FEC。
    The American Board of Surgery (ABS) has required Fundamentals of Endoscopic Surgery (FES) certification for general surgery applicants since 2018. Flexible Endoscopy Curriculum (FEC) completion is recommended prior to taking the FES exam. The objective of the study was to determine if FEC completion prepares individuals to pass the FES manual skills test.
    Participants included first-attempt FES examinees from June 2014 to February 2019. De-identified data were reviewed, Self-reported data included gender, PGY, glove size, upper (UE) and lower (LE) endoscopy experience, simulation training time, and participation in an endoscopy rotation (ER). FES skills exam performance was reported by FES staff. Those completing all vs. none of the FEC were compared.
    Of 2023 participants identified, 809 (40.0%) reported completion of all FEC components, 1053 (52.1%) completed of some, and 161 (8.0%) completed none. Men and candidates taking FES later in residency were more likely to complete all FEC requirements (p = 0.002, p < 0.001). FES pass rates were higher for those who completed all FEC components compared to those who completed none (88.4% vs 72.7%, p < 0.001). On logistic regression analysis, completion of all components (OR 2.3, 95% CI 1.5-3.7, p < 0.001) and male gender (OR 3.1, 95% CI 1.7-5.7, p < 0.001) were predictors of passing, while glove size (OR 1.5, 95% CI 1.0-2.5, p = 0.08), simulator time (OR 1.1, 95% CI 0.9-1.4, p = 0.37) and PGY were not (OR 1.1, 95% CI 0.9-1.4, p = 0.38). On multivariate analysis controlling for glove size and gender, completion of all FEC components was still associated with a higher likelihood of passing the FES skills exam (OR 1.6, 95% CI 1.2-2.1, p < 0.001).
    Completion of FEC is strongly associated with passing the FES skills test. This study supports the ABS recommendation for completion of FEC prior to taking the FES skills test.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    Raising electrocatalysis by rationally devising catalysts plays a core role in almost all renewable energy conversion and storage systems. The principal catalytic properties can be controlled and improved well by manipulation of interfaces, ascribed to the interactions among different components/players at the interfaces. In particular, manipulating interfaces down to atomic scales is becoming increasingly attractive, not only because those atoms at around the interface are the key players during electrocatalysis, but also, understandings on the atomic level electrocatalysis allow one to gain deep insights into the reaction mechanism. With the feature down-sizing to atomic scales, there is a timely need to redefine the interfaces, as some of them have gone beyond the conventionally perceived interfacial concept. In this overview, the key active players participating in the interfacial manipulation of electrocatalysts are examined, from a new angle of \"atomic interface,\" including those individual atoms, defects, and their interactions, together with the essential characterization techniques for them. The specific approaches and pathways to engineer better atomic interfaces are investigated, and thus to enable the unique electrocatalysis for targeted applications. Looking beyond recent progress, the challenges and prospects of the atomic level interfacial engineering are also briefly visited.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Sci-hub)

  • 文章类型: Journal Article
    OBJECTIVE: As the Fundamentals of Laparoscopic Surgery (FLS) and Fundamentals of Endoscopic Surgery (FES) have been used for general surgery assessment, the Fundamentals of Vascular Surgery (FVS) has recently been developed to evaluate core operative skills for vascular trainees. This study examines the 3 year implementation of FVS for general surgery residents and it gathers validity evidence using Messick\'s framework. We hypothesized that the curriculum and assessment tool enhance general surgery resident training and assessment.
    METHODS: This is a retrospective review of FVS assessments of residents using descriptive and multivariate analyses.
    METHODS: This study was conducted at an academic institution, where simulation-based teaching sessions occur in coordination between the general surgery and the integrated vascular surgery residency programs.
    METHODS: Seventeen general surgery residents were assessed in FVS skills by an expert rater from 2018 to 2020.
    RESULTS: Overall, 86 assessments were completed.
    BACKGROUND: Assessment focuses on 3 open vascular skills (End-to-Side Anastomosis, Patch Angioplasty and Clockface Suturing). Response Process: 7 items comprise a graded rating for a skills score. Additionally, a global summary score is designated. Internal Structure: The assessment tool has a Cronbach\'s alpha of 0.87, demonstrating good internal consistency. Addition of the second rater correlated with Cohen\'s kappa -0.69 (p < 0.001), indicating poor interrater reliability. Relationships to other variables: The most significant improvement occurred in total scores between PGY2s (17.4 ± 2.37) and PGY4s (23.2 ± 3.00), p < 0.001, indicating adequate level discernment.
    CONCLUSIONS: The validity evidence of FVS assessment in this study supports its use in general surgery residency at a time when opportunities for open vascular skills assessment may be decreasing due to case availability and shifting paradigms. Further study into quality rater training is needed to optimize national implementation of FVS and ensure consistency in grading.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Sci-hub)

  • 文章类型: Journal Article
    As a ubiquitous vapor-liquid phase-change process, dropwise condensation has attracted tremendous research attention owing to its remarkable efficiency of energy transfer and transformative industrial potential. In recent years, advanced functional surfaces, profiting from great progress in modifying micro/nanoscale features and surface chemistry on surfaces, have led to exciting advances in both heat transfer enhancement and fundamental understanding of dropwise condensation. In this review, we discuss the development of some key components for achieving performance improvement of dropwise condensation, including surface wettability, nucleation, droplet mobility, and growth, and discuss how they can be elaborately controlled as desired using surface design. We also present an overview of dropwise condensation heat transfer enhancement on advanced functional surfaces along with the underlying mechanisms, such as jumping condensation on nanostructured superhydrophobic surfaces, and new condensation characteristics (e.g., Laplace pressure-driven droplet motion, hierarchical condensation, and sucking flow condensation) on hierarchically structured surfaces. Finally, the durability, cost, and scalability of specific functional surfaces are focused on for future industrial applications. The existing challenges, alternative strategies, as well as future perspectives, are essential in the fundamental and applied aspects for the practical implementation of dropwise condensation.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Sci-hub)

  • 文章类型: Journal Article
    CE-MS作为代谢组学的分析工具越来越有动力,由于它能够获得有关生物样品中最极性元素的信息。通过电泳图(动员图)的迁移率标度表示,提高了峰识别的鲁棒性,这一点得到了帮助。作为促进将CE-MS用于非靶向代谢组学数据的必要步骤,作者以前开发和介绍了罗马,通过简单且独立的用户界面自动生成大型非目标数据集的移动图的软件。在这里,我们引入了新版本的ROMANCE,包括与其他类型数据(目标MS数据和2DUV-Vis吸收样电泳图)的兼容性等新功能,以及转换参数中非常需要的额外灵活性(包括字段斜坡和二级标记的使用),更多的测量条件(取决于检测和积分模式),最重要的是解决定量峰值转换的问题。首先,我们对当前关于峰值表征的理论框架进行了回顾,我们开发了多标记峰面积校正的新公式,为了预测峰值位置精度,并用于评估峰形畸变。然后,软件的新版本是提出和实验验证。我们将多标记物移动性转换与以前的结果进行了对比,发现峰值位置精度提高,最后,我们展示了实际非目标代谢组学数据的应用。
    CE-MS is increasingly gaining momentum as an analytical tool in metabolomics, due to its ability to obtain information about the most polar elements in biological samples. This has been helped by improvements of robustness in peak identification by means of mobility-scale representations of the electropherograms (mobilograms). As a necessary step toward facilitating the use of CE-MS for untargeted metabolomics data, the authors previously developed and introduced ROMANCE, a software automating mobilogram generation for large untargeted datasets through a simple and self-contained user interface. Herein, we introduce a new version of ROMANCE including new features such as compatibility with other types of data (targeted MS data and 2D UV-Vis absorption-like electropherograms), and the much needed additional flexibility in the transformation parameters (including field ramping and the use of secondary markers), more measurement conditions (depending on detection and integration modes), and most importantly tackling the issue of quantitative peak conversion. First, we present a review of the current theoretical framework with regard to peak characterization, and we develop new formulas for multiple marker peak area corrections, for anticipating peak position precision, and for assessing peak shape distortion. Then, the new version of the software is presented and validated experimentally. We contrast the multiple marker mobility transformations with previous results, finding increased peak position precision, and finally we showcase an application to actual untargeted metabolomics data.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Sci-hub)

       PDF(Pubmed)

  • 文章类型: Journal Article
    Alkali and alkaline earth metal adducts of a branched glycan, XXXG, were analyzed with helium charge transfer dissociation (He-CTD) and low-energy collision-induced dissociation (LE-CID) to investigate if metalation would impact the type of fragments generated and the structural characterization of the analyte. The studied adducts included 1+ and 2+ precursors involving one or more of the cations: H+ , Na+ , K+ , Ca2+ , and Mg2+ . Regardless of the metal adduct, He-CTD generated abundant and numerous glycosidic and cross-ring cleavages that were structurally informative and able to identify the 1,4-linkage and 1,6-branching patterns. In contrast, the LE-CID spectra mainly contained glycosidic cleavages, consecutive fragments, and numerous neutral losses, which complicated spectral interpretation. LE-CID of [M + K + H]2+ and [M + Na]+ precursors generated a few cross-ring cleavages, but they were not sufficient to identify the 1,4-linkage and 1,6-branching pattern of the XXXG xyloglucan. He-CTD predominantly generated 1+ fragments from 1+ precursors and 2+ product ions from 2+ precursors, although both LE-CID and He-CTD were able to generate 1+ product ions from 2+ adducts of magnesium and calcium. The singly charged fragments derive from the loss of H+ from the metalated product ions and the formation of a protonated complementary product ion; such observations are similar to previous reports for magnesium and calcium salts undergoing electron capture dissociation (ECD) activation. However, during He-CTD, the [M + Mg]2+ precursor generated more singly charged product ions than [M + Ca]2+ , either because Mg has a higher second ionization potential than Ca or because of conformational differences and the locations of the charging adducts during fragmentation. He-CTD of the [M + 2Na]2+ and the [M + 2 K]2+ precursors generated singly charged product ions from the loss of a sodium ion and potassium ion, respectively. In summary, although the metal ions influence the mass and charge state of the observed product ions, the metal ions had a negligible effect on the types of cross-ring cleavages observed.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Sci-hub)

       PDF(Pubmed)

  • 文章类型: Journal Article
    循证医学的前提是将最佳研究证据与临床专业知识和患者价值相结合,以告知护理。在医学研究中,通常使用几种不同的度量来描述变量之间的关联,对这些普遍措施的良好理解是临床医生解释能力的基础,合成,并应用医学文献中的现有证据。因此,本文旨在提供有关医学研究中一些最普遍的关联和风险量化措施的教育教程/主题入门,包括赔率比,相对风险,绝对风险,以及需要治疗的数量,使用医学文献中的几个现实世界的例子。
    Evidence-based medicine is predicated on the integration of best available research evidence with clinical expertise and patient values to inform care. In medical research, several distinct measures are commonly used to describe the associations between variables, and a sound understanding of these pervasive measures is foundational in the clinician\'s ability to interpret, synthesize, and apply available evidence from the medical literature. Accordingly, this article aims to provide an educational tutorial/topic primer on some of the most ubiquitous measures of association and risk quantification in medical research, including odds ratios, relative risk, absolute risk, and number needed to treat, using several real-world examples from the medical literature.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Sci-hub)

       PDF(Pubmed)

公众号