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关键词： 食品   微生物   污染   分析  

摘要： 由于食品中有大量的营养成分,所以为微生物的生长创造了良好的生存环境,也因此使食品在加工过程中容易受到微生物的污染,现阶段,这种食品污染已成为广大消费者和生产者共同关注的热点话题,食品污染为人们的身体健康带来了巨大隐患,尤其是现在社会中广泛出现的食物中毒问题,造成了大多数人们得了食源性疾病,毒物会导致集体正常的生理工程造成破坏,从而引发集体中毒,甚至会导致身体死亡的可怕性毒物。那么,如何有效控制这种污染呢。

关键词： 标本制备   实验室   医院   质量控制  

摘要： 目的对不合格临床检验标本进行综合分析，探讨原因及发生的比例，达到提高标本分析前质量的目的。方法采用回顾性研究方法，分析2012年3月至2013年2月广州军区广州总医院分析前不合格的血液标本1728例、尿液标本829例、粪便标本372例，运用统计学方法对数据进行综合分析。结果血液、尿液、粪便标本不合格率分别是3．71‰、3．61‰、11．53‰。不合格原因：血液标本以标本凝块最常见占3．42‰，其中又以紫色EDTA-K：管发生标本凝块的风险最高（x^2=248．779，P〈0．001）；尿液不合格标本主要原因是量少占2．08‰；粪便不合格主要原因是无标本占7．19‰。结论及时反馈结果给临床医护人员，共同建立完善的控制标本不合格率的制度，降低标本不合格率，确保分析前质量。

关键词： 农民工   工资率   劳动合同形式   分位数回归  

摘要： 本文基于国家卫生计生委流动人口动态监测调查数据,依托OLS方法检验劳动合同形式对农民工工资率的影响,并借助分位数回归方法细致深入地诠释其作用机制。研究结果表明,签订劳动合同将会显著提升农民工的工资率,有固定期限的劳动合同对农民工,尤其是对中低收入的农民工,工资促进效应更为突出。

关键词： Switching costs   Changed preferences   Contract design   Equilibrium price  

摘要： This paper compares three contract forms, including short-term contract with price discrimination, short-term contract without price discrimination, and long-term contract with price commitment for consumers with switching costs and changed preferences. We find that long-term contract generates the largest profit for firms. Moreover, we find that switching costs make the market more competitive when consumers have changed preferences, and the higher the switching costs, the more competitive. Our theory combines linear-city duopoly and switching-cost model and the results are consistent with literature, for example price commitment is valuable. Our findings shed light on the practice of different forms of dynamic pricing in various industries including telecommunication industry and airline industry. (C) 2015 Elsevier B.V. All rights reserved.

关键词： incivility   self-control   exhaustion   interaction records   diary study  

摘要： Scholars have hypothesized that experiencing incivility not only negatively affects well-being, but may even trigger further antisocial behavior. Previous research, however, has focused mainly on the relation between incivility and well-being. Thus, little is known about the behavioral consequences of incivility. With this in mind, we conducted an interaction-record diary study to examine whether supervisor incivility causes retaliatory incivility against the supervisor. Using the self-control strength model as a framework, we further examined whether the target's trait (trait self-control) and state (exhaustion) self-regulatory capacities moderate this effect. In addition, we examined the role of time by testing the duration of the effect. When we analyzed the full data set, we found no support for our hypotheses. However, using a subset of the data in which the subsequent interaction happened on the same day as the prior interaction, our results showed that experiencing incivility predicted incivility in the subsequent interaction, but only when the time lag between the two interactions was short. Furthermore, in line with the assumption that self-regulatory capacities are required to restrain a target from retaliatory responses, the effect was stronger when individuals were exhausted. In contrast to our assumption, trait self-control had no effect on instigated incivility. Copyright (c) 2015 John Wiley & Sons, Ltd.

关键词： hydrazone   Raman   gold nanoparticles   surface anchoring mode   pH-dependent cleavage  

摘要： We conducted a comparative study of the pH-dependent anchoring behaviors of 3-methyl-2-benzothiazolinone hydrazone (3M2BH) and benzophenone hydrazone (BPH) on gold nanoparticles (AuNPs) by means of interfacial Raman spectroscopy. We found that several bands of 3M2BH in the highly alkaline pH region disappeared as the colloidal conditions became more neutral and acidic. The vibrational band at 919, 1174, and 1222 cm(-1) at pH 10.0 disappeared below pH 9.2, which may be because of the hydrolysis reactions that cleave the labile =N-NH2 group of 3M2BH, indicating a rather perpendicular orientation via the sulfur atom at the surfaces. A fairly high transition pH value was assumed to be because of the interaction of the =N-NH2 group in the vicinity of the surfaces. Several characteristic bands, including 1584 and 1617 cm(-1), also exhibited different intensities, suggesting that the adsorbates on Au surfaces underwent structural transformations of the =N-NH2 group after the pH value became neutral or acidic. These changes were not observed for BPH, presumably because of the direct and robust binding of the hydrazone onto Au surfaces. Our results revealed that the pH-dependent cleavage reactions may vary depending on the surface anchoring modes of the adsorbates. Copyright (C) 2015 John Wiley & Sons, Ltd.

关键词： Milk analysis   Solubilization with N,N-dimethylformamide, High efficiency sample introduction system   Inductively coupled plasma mass spectrometry   Principal component analysis  

摘要： A single-step procedure for trace elements analysis of milk samples is presented. Solubilization with small amounts of dymethylformamide (DMF) was assayed prior to inductively coupled plasma mass spectrometry (ICPMS) detection with a high efficiency sample introduction system. All main instrumental conditions were optimized in order to readily introduce the samples without matrix elimination. In order to assess and mitigate matrix effects in the determination of As, Cd, Co, Cu, Eu, Ga, Gd, Ge, Mn, Mo, Nb, Nd, Ni, Pb, Pr, Rb, Sm, S, Sr, Ta, Tb, V, Zn, and Zr, matrix matching calibration with Rh-103 as internal standard (IS) was performed. The obtained limits of detection were between 0.68 (Tb) and 30 (Zn) mu g L-1. For accuracy verification, certified Skim milk powder reference material (BCR 063R) was employed. The developed method was applied to trace elements analysis of commercially available milks. Principal components analysis was used to correlate the content of trace metals with the kind of milk, obtaining a classification according to adults, baby or baby fortified milks. The outcomes highlight a simple and fast approach that could be trustworthy for routine analysis, quality control and traceability of milks. (C) 2015 Elsevier B.V. All lights reserved.

关键词： 贫血   鉴别诊断   血液检验   临床分析  

摘要： 目的研究血液检验在贫血类型的鉴别诊断中的发挥的作用。方法该院选择2013年3月—2015年3月间诊治的120例贫血患者,根据贫血类型将其分为两组,60例为溶血性贫血组,60例为缺铁性贫血组,同时选择60例正常的患者进行对比分析,对所选患者进行血细胞检测,比较3组患者血液中的红细胞(RBC)、平均红细胞容积(MCV)、血红蛋白(Hb)、平均红细胞血红蛋白(MCH)、红细胞分布宽度(RDW)等存在的差异,同时比较观察组的两组患者特异性、灵敏度以及符合率之间的不同。结果通过对3组患者进行比较,溶血性贫血组患者中的RBC明显比对照组低,缺铁性贫血组患者的Hb指标明显比对照组及溶血性贫血组患者低,而3组患者中,对照组患者的MCH最高,3组患者差异有统计学意义(P<0.05)。缺铁性贫血组及溶血性贫血组患者血液检测的特异度、灵敏度以及符合率差异无统计学意义(P>0.05)。结论通过血液检测能够分辨出一些贫血类型,通过比较简单方便的方法进行鉴别诊断,能够有效提升贫血的筛查诊断。

关键词： 社会资本   异质性   农民工   就业过程  

摘要： 本文利用2014年北京市农民工调查数据,基于过程推进视角实证检验了异质性社会资本对于农民工职业获取、职业流动及职业发展的影响效应。研究发现,农民工的城市就业存在明显的职业分割;"整合型"社会资本对于农民工实现低端就业具有促进作用,拥有"跨越型"社会资本能够降低农民工低端就业的可能性,但两类社会资本对于农民工获取中高端职业身份均没有显著影响,且也不会造成农民工更频繁的职业流动。同时,"跨越型"社会资本对农民工职业发展具有显著的正向影响,"整合型"社会资本反而会制约农民工向上的职业流动。此外,受教育程度、职业培训经历和外出务工经历都对农民工的职业发展具有回报效应。

关键词： 生化指标   肝硬化   作用  

摘要： 目的：探讨生化检验指标在肝硬化疾病诊断中的作用。方法选取2015年3月～2015年9月在我院进行肝硬化诊断的患者58例，将患者作为观察组，另外从健康中心选取进行过体检的健康人员58例，作为对照组，对两组患者进行生化检验，并对生化检验指标进行比较。结果经过检验，观察组患者的天冬氨酸氨基转移酶、白蛋白、总胆红素以及球蛋白的比值，高于对照组成员。另外，检验中，还发现观察组患者的Ⅲ型前胶原、血清透明质酸、Ⅳ型胶原以及层粘连蛋白等比对照组的人员数值高。结论在对肝硬化患者的诊断中，生化指标检验，可以作为肝硬化患者诊断的重要指标和诊断依据，可帮助患者了解治疗缩短的时间，进而更好地实现针对性的治疗。