N-Cyclohexyl-N′ -isopropylcarbodiimide: a hybrid that combines the structural features of DCC and DIC

N-Cyclohexyl-N′ -isopropylcarbodiimide was prepared and used for peptide couplings by various procedures. Reaction between Z-Val and Gly-OEt was used for yield studies and determination of the extent of the side reaction in solution. The value of this reagent for solid peptide synthesis was demonstrated by the synthesis of sequences comprising the 65–74 residues of acyl carrier protein. The efficiency of activation was determined by competition experiments. From all these studies the conclusion can be drawn that N-cyclohexyl-N′-isopropylcarbodiimide is comparable to or even better than the commonly used DCC for mediation of peptide bond formation in solid phase synthesis. By virtue of the solubility of N-cyclohexyl-N′-isopropylurea in dichloromethane, the carbodiimide seems to be a good candidate for practical execution of peptide bond formation by the standard carbodiimide procedure.     

基本技能比赛在外科学总论实习教学中的应用与评价

在外科学总论实习教学中,通过举办基本技能比赛,将日常教学与比赛内容紧密结合,充分发挥教师与学生的主观能动性,促进学生的训练和学习.比赛后对学生的问卷调查以及比赛成绩与考试成绩的分析结果表明,比赛有助于提高学生的外科学基本技能.     

竞争模型假设与广义F检验的研究

在传统教科书中,如象t检验、方差分析、回归分析、协方差分析等统计假设检验方法的目的都可以归纳为究竟选用什么数学模型来分析观察数据的结构的问题。本文所提出广义F检验的方法就是这一思想的体现。该法不仅逻辑清晰、易于理解,而且使很多传统假设检验方法在竞争模型假设的思想下形成系统化的概念。广义F检验有三个步骤:(一)根据观察资料的特征及研究的目的建立某些竞争模型假设,每一假设为观察数据的拟合提供一个数学模型;(二)计算观察数据拟合每个竞争模型的剩余平方和及自由度;(三)计算广义F值,并根据相应的F分布的概率特征对竞争模型作出合理的推断。     

Measurement of tumour reactive antibody and antibody conjugate by competition, quantitated by flow cytofluorimetry

Binding of unlabelled monoclonal antibody preparations has been assessed by cometition at saturation with fluorochrome labelled homologous antibody for binding to antigen bearing target cells. The extent of competition was measured by quantitative flow cytofluorimetry, and simple mathematical procedures have been developed to allow the interpretation of competition data in terms of antibody binding activity. In the system studied, non-specific (non-competitive) fluorescence was minimal, but an iterative method to calculate its contribution to the measured signal is given. This approach has the advantage that the antibody preparation to be tested does not need to be labelled or modified; this is particularly important when evaluating the binding activity of therapeutic antibody conjugates. Comparison with a well characterized standard antibody preparation provides a rapid, sensitive and accurate quality control procedure. This test is also simple to perform, requiring only the mixing of labelled and unlabelled antibodies with target cells, a single incubation, followed by analysis without washing of the target cells.     

Hospital competition, managed care, and mortality after hospitalization for medical conditions in California

OBJECTIVE: To assess the effect of hospital competition and health maintenance organization (HMO) penetration on mortality after hospitalization for six medical conditions in California. DATA SOURCE: Linked hospital discharge and vital statistics data for short-term general hospitals in California in the period 1994-1999. The study sample included adult patients hospitalized for one of the following conditions: acute myocardial infarction (N=227,446), hip fracture (N=129,944), stroke (N=237,248), gastrointestinal hemorrhage (GIH, N=216,443), congestive heart failure (CHF, N=355,613), and diabetes (N=154,837). STUDY DESIGN: The outcome variable was 30-day mortality. We estimated multivariate logistic regression models for each study condition with hospital competition, HMO penetration, hospital characteristics, and patient severity measures as explanatory variables. PRINCIPAL FINDINGS: Higher hospital competition was associated with lower 30-day mortality for three to five of the six study conditions, depending on the choice of competition measure, and this finding was robust to a variety of sensitivity analyses. Higher HMO penetration was associated with lower mortality for GIH and CHF. CONCLUSIONS: Hospitals that faced more competition and hospitals in market areas with higher HMO penetration provided higher quality of care for adult patients with medical conditions in California. Studies using linked hospital discharge and vital statistics data from other states should be conducted to determine whether these findings are generalizable.     

护生竞争与合作策略取向的研究与分析

竞争与合作是获取成功的2种不同策略。大学生对于合作与竞争的态度在一定程度上反映了学习的动力、对获取成功的策略取向以及自我评价能力的高低,能为素质教育提供有用的参考工具[1]。21世纪,护理专业的发展对护理人员提出了“既要有知识、技能,还要有团结精神与人合作的能力”     

2013年全国寄生虫病防治技术竞赛成绩分析:蠕虫检测能力分析

目的了解我国各级疾控机构寄生虫病防治人员的蠕虫检测能力,推动各级疾控机构能力建设。方法 2013年6月,以省为单位,每省选送4名疾控机构在职专业技术人员参加全国寄生虫病防治技术竞赛,收集竞赛结果进行分析。结果来自全国30个省(市、自治区)和新疆生产建设兵团的31支代表队共124人参赛,选手的蠕虫镜检及制片平均成绩分别为27.3分和7.6分,较2012年均有显著提高(t=3.169、5.009,P均0.05)。蠕虫平均检出率为62.7%,较2012年显著提高(c2=28.630,P0.05)。不同性别、年龄、职称选手的成绩差异有统计学意义(t=1.400、2.080,F=2.366~3.864,P均0.05),有血防任务的省份成绩显著高于无任务的省份(t=6.650、4.630,P均0.01)。结论全国寄生虫病防治技术竞赛提高了各省寄生虫病防治专业人员,尤其是年轻人员的专业技术能力,但选手对常见土源性线虫虫卵的识别能力有待加强。建议在寄生虫病低度流行区和无防治任务的省份设立监测点,并加大人才培养力度。     

What makes a great resident? The programme director perspective

A career in orthopedic surgery in the United Kingdom is highly competitive. Great residents are trainees who understand that ultimately, they are responsible for their own training. They need to work with their Training Program Director to plan their career, to develop as surgeons, to reflect on their performance and any feedback they receive, be flexible, and plan ahead. There is competition but it is fair for everyone and the great resident will excel within this environment and will be successful in the long term.