Estimation methods for Maximum Residue Limits for pesticides

Maximum Residue Limits (MRLs) are standards that represent the maximum residue concentration expected to be found if a pesticide is applied according to good agricultural practice (GAP). MRLs are established only where the residues in food resulting from particular use patterns of the pesticide pass the public health risk assessment. Foodstuffs are monitored for MRL compliance and MRL exceedance can have economic and trade consequences. There is a trade-off when deciding on values for MRLs. The aim is to establish MRLs at levels that are high enough to prevent chance exceedance but not so high that misuse will not be detected. Small data sets typically available for estimating MRLs present problems for establishing consistent values. A review of MRL estimation methods is presented together with an assessment of the various methods.     

牛奶及奶制品中兽药残留的监控

在食品安全领域中，兽药残留控制计划程序是一新的管理模式。本文较全面系统地阐述了食源性动物兽药的应用特点；制定监控计划的基本原则；主管机构、生产企业及检测实验室的主要责任；监控结果及反馈控制程序；监控样品抽取及传递程序；监控检测实验室及管理等各主要环节的制定原则及实施要点。为牛奶及奶制品中兽药残留监控计划的科学制定提供了系统的参考依据。     

HPLC法测定动物源性食品中呋喃唑酮残留的研究

〔目的〕建立一套适用于批量样品检测的动物源性食品中呋喃唑酮的检测方法。〔方法〕该法采用乙腈做提取剂 ,经过提取、净化、过滤、浓缩 ,即可直接上样分析。〔结果〕该法简便、快速、稳定、易于掌握 ,回收率高 ,经济适用。当取样量为 10 .0g时 ,该法的最低检测限量为 1.0 μg ml ,已达到欧盟对我国出口水产品检测限量的要求。应用该法 ,测定了余杭区地产畜禽、水产品 68份。检出含呋喃唑酮的样品 3 5份 ,检出率为 5 1.4%。呋喃唑酮残留量范围 :1.3～ 5 4 4μg kg。〔结论〕该法简便、快速且敏感性好。     

Insecticide and fungicide effect on thermal and olfactory behavior of bees and their disappearance in bees’ tissues

Plant protection products may affect the behavior of organisms which are not a target of control. The effect of Karate Zeon 050 CS (λ-Cyhalothrin -based insecticide; λ-CBI) and Amistar 250 SC (Azoxystrobin-based fungicide; ABF) was determined on Apis mellifera worker attraction towards their own colony odour, along with temperature preferences. Bees exposed to pesticides prefer the environment with the odour of their nest less often than the control group, and that insecticide-treated bees chose warmer environments than the control insects. The observed differences in the bees, especially with attraction towards their own colony, were dependent on the time of day. Chromatographic analyses indicated that λ-Cyhalothrin elimination was half that of Azoxystrobin in bee organisms, and both agents retarded each other’s clearance. Mathematical modeling estimated that despite a relatively high disappearance rate, both compounds might have been bio-accumulated at relatively high level.     

不同病灶部位脑卒中患者吞咽障碍特点分析

目的 探讨不同病灶部位脑卒中患者吞咽障碍特点。 方法 纳入2015年1月至2016年8月期间在我院治疗且病变局限于单侧大脑或脑干的92例脑卒中患者作为研究对象。根据病变部位分为3组,其中单侧脑干病变29例（纳入单侧脑干组）,左侧半球（皮质+白质）病变37例（纳入左侧半球组）,右侧半球（皮质+白质）病变26例（纳入右侧半球组）。入院后所有患者进行吞咽造影检查,记录并对比各组患者口腔运送、吞咽启动、残留、渗漏、误吸、咳嗽反射及环咽肌开放等指标结果。 结果 3组患者在口腔运送（χ2=0.712,P=0.918）、吞咽启动（χ2=1.564,P=0.458）、渗漏（χ2=5.615,P=0.060）、咳嗽反射（χ2=5.882,P=0.053）方面组间差异均无统计学意义,单侧脑干组在会厌谷、梨状窦残留（χ2=6.508,P=0.011）和误吸（χ2=7.803,P=0.005）方面与左侧半球组间差异具有统计学意义,单侧脑干组在环咽肌开放方面与左侧半球组及右侧半球组间差异均具有统计学意义（χ2分别为29.555和24.630,均P<0.05）。 结论 单侧脑干较单侧大脑半球卒中更容易发生咽期吞咽障碍,主要表现为残留、误吸及环咽肌开放异常等方面,两侧大脑半球卒中后吞咽障碍特点无明显差异。     

Separating stimulus‐driven and response‐related LRP components with Residue Iteration Decomposition (RIDE)

When the lateralized readiness potential (LRP) is recorded in stimulus–response compatibility (SRC) tasks, two processes may overlap in the LRP, stimulus‐driven response priming and activation based on response selection rules. These overlapping processes are hard to disentangle with standard analytical tools. Here, we show that Residue Iteration Decomposition (RIDE), based on latency variability, separates the overlapping LRP components from a Simon task into stimulus‐driven and response‐related components. SRC affected LRP amplitudes only in the stimulus‐driven component, whereas LRP onsets were affected only in the response‐locked component. Importantly, the compatibility effect in reaction times was more similar to the effect in the onsets of the RIDE‐derived response‐locked LRP component than in the unseparated LRP. Thus, RIDE‐separated LRP components are devoid of distortions inherent to standard LRPs.     

2018年秦山核电站周边饮用水中总α和总β放射性水平的监测与分析

目的 了解秦山核电站周边的饮用水中总α、总β放射性本底水平。方法 根据国家卫生健康委员会方案,2018年在海盐县内距秦山核电站周围30 km范围内的11个监测点,在上半年和下半年分别采集水源水、出厂水和管网末梢水各1次,依据GB/T 5750.13-2006《生活饮用水标准检验方法放射性指标》进行采样、检测分析。检测的饮用水中总α、总β放射性水平按GB 5749-2006《生活饮用水卫生标准》进行评价,并比较2018年与2016-2017年末梢水中总α、总β放射性水平。结果 11个采样点分别在2018年4月和9月共采得水样22份,测得饮用水蒸干后的残渣率与不同类型水体有关,水源水残渣率稍高,达0.033 7%。不同类型水体中总α放射性水平范围为0.008~0.040 Bq/L,平均值为（0.015±0.009）Bq/L,总β放射性水平范围为0.014~0.320 Bq/L,平均值为（0.188±0.068）Bq/L。水源水和出厂水总α放射性水平比较,差异具有统计学意义（Z=-2.286,P<0.05）;残渣量与总α、总β放射性水平无线性关系,差异均无统计学意义（P>0.05）。2018年末梢水与2016-2017年比较,总α、总β放射性水平比较差异有统计学意义（Z=-2.976、-2.031,P<0.05）,2017年末梢水与2016年比较,总α、总β放射性水平比较差异有统计学意义（Z=-2.042、-3.214,P<0.05）,2018年末梢水与2017年比较,总α、总β放射性水平比较差异有统计学意义（Z=-20.112、-2.511,P<0.05）,但均符合标准要求。结论 核电站运行未对其周围饮用水的放射性水平产生影响,秦山核电站周围饮用水是安全的。     

Protein Interfacial Pocket Engineering via Coupled Computational Filtering and Biological Focusing Criterion

To engineer bio-macromolecular systems, protein–substrate interactions and their configurations need to be understood, harnessed, and utilized. Due to the inherent large numbers of combinatorial configurations and conformational complexity, methods that rely on heuristics or stochastics, such as practical computational filtering (CF) or biological focusing (BF) criterions, when used alone rarely yield insights into these complexes or successes in (re)designing them. Here we use a coupled CF–BF criterion upon an amenable interfacial pocket (IP) of a protein scaffold complexed with its substrate to undergo residue replacement and R-group refinement (R⁴) to filter out energetically unfavorable residues and R-group conformations, and focus in on those that are evolutionarily favorable. We show that this coupled filtering and focusing can efficiently provide a putative engineered IP candidate and validate it computationally and empirically. The CF–BF criterion may permit holistic understanding of the nuances of existing protein IPs and their scaffolds and facilitate bioengineering efforts to alter substrate specificity. Such approach may contribute to accelerated elucidation of engineering principles of bio-macromolecular systems. Electronic supplementary material The online version of this article (doi: ) contains supplementary material, which is available to authorized users.     

137颗残根残冠治疗与修复的临床效果分析

目的 探讨残根残冠经根管治疗与冠修复后的临床治疗效果.方法 选择2001～2005年在门诊收治的137颗残根残冠为研究对象,经根管治疗后行桩核冠修复,随访观察6个月～4年,分析其临床疗效.结果 经6个月～4年随访,137颗患牙中122颗修复成功,8颗牙根出现不同程度的松动,4颗出现龈瘘,1例核桩因继发龋脱落;2例因牙周炎拔牙.结论 在严格选择适应证的前提下,残根残冠经完善根管治疗与冠修复后可达到满意的临床治疗效果.     

杰力试纸法在检测手术器械残留血渍中的应用

目的检测常规经手刷清洗后的手术器械有无残留血渍. 方法经对国内7所大医院洗涤后1 044件手术器械,用杰力试纸法检测常规方法清洗的手术器械的洁净度. 结果经目测确认符合清洁的标准,再用试纸法检测,其残留血渍检出阳性率39.6%. 结论手术后的器械要彻底刷洗达到清洁,但目前缺乏科学客观的检测手段检验清洗程度,杰力试纸对清洗后器械的洁净检测提供了一个较好的方法.