2014年参加全国γ能谱分析质量控制比对结果

目的 总结2014年放射性核素γ能谱分析质量控制比对,验证放射性核素分析方法的可靠性。方法 采用国家标准,利用γ能谱仪分析土壤比对样品中²⁰⁸Tl、¹³⁷Cs、²²⁸Ac和⁴⁰K放射性核素的含量。结果 我所实验室比对样品的测量值相对校准值偏差均< 10%,各核素比对结果无论是准确度还是精确度均满足比对要求,判定结果为"合格"。结论 比对结果证明,我所γ能谱测量系统的质量保证体系和质量控制技术是完善和有效的,放射性核素的测量分析方法、数据的处理方法也是可靠的。     

核辐射应急情况下放射性核素的γ能谱快速分析方法

目的 建立核辐射事件发生后应急情况下环境样品中放射性核素的γ能谱快速分析方法。方法 通过调研国内外核辐射应急标准，并结合我国实际，制定了在核辐射事件发生后应急情况下，对环境样品样品的采集、预处理、γ能谱测量、出具结果报告的流程。结果 采用2 L马林杯样品盒，在测量10 min的情况下，¹³¹I和¹³⁷Cs的最小可探测活度浓度在10²（Bq/kg）量级。结论 建立了一种测量核辐射应急情况下放射性核素的γ能谱快速分析方法，满足核应急情况下对OIL6中的要求。     

Genie2000软件在环境样品测量中的应用

目的 通过对Genie2000软件的应用,提高对γ能谱分析软件的认识,更加精确地完成γ能谱测量工作。方法 以环境样品为例,介绍γ谱分析软件Genie2000的应用。结果 规范Genie2000分析放射性核素的方法。结论 通过对Genie2000软件的熟练使用,可快速、准确的分析环境样品中放射性核素的活度。     

2018年参加全国放射性核素γ能谱分析比对结果

目的 验证本实验室所用的γ能谱测量系统,确认γ放射性核素测量分析方法和技术的可靠性。方法 通过参加2018年中国疾病预防控制中心辐射防护与核安全医学所组织的全国放射性核素γ能谱质量控制分析比对,分别用相对比较法和效率曲线法分析土壤样品中核素²³²Th、⁴⁰K、¹³⁷Cs的活度浓度。结果 相对比较法测得的3种核素的活度浓度与参考值的偏差为0%~14.1%,U检验值为0.15~2.35;效率曲线法测得的3种核素的活度浓度相对参考值的偏差为2.8%~18.5%,U检验值为0.42~2.58,均在合格范围内。结论 本实验室所用的γ能谱测量系统性能稳定,分析方法可靠,但测量结果与参考值的相对偏差较大,实验室质量控制技术有待进一步完善。     

2009-2016年高纯锗γ能谱分析方法比对结果分析

目的 保证高纯锗γ能谱仪对样品中放射性核素含量检测的准确度，不断提高实验室放射性核素的检测分析水平。方法 连续参加由中国疾病预防控制中心组织的全国放射性核素γ能谱分析能力比对考核，对2009-2016年的比对测量结果进行分析。结果 本实验室2009-2016年比对考核结果均为合格，25个测量结果的相对偏差范围在-17.58%至13.06%之间。结论 本实验室使用的放射性核素的测量分析方法正确，出具的检测报告准确可信。     

全身计数器NaIγ谱的非线性曲线拟合重峰分析

目的 给出全身计数器NaIγ谱中²¹⁴Bi、¹³⁷Cs的609.3keV、661.66keV全能峰计数率。方法 采用已知活度的¹³⁷Cs放射性点源进行测量,对γ谱中感兴趣区域,利用基于Matlab的非线性曲线拟合方法进行重峰分析。结果 分析得出的¹³⁷Cs活度测量值与已知活度间相对偏差的绝对值小于10%。结论 非线性曲线拟合方法是一种简便、快捷、可靠的重峰分析方法之一。     

2018—2020年参加全国放射性核素γ能谱考核结果分析

目的 保证γ放射性核素实验室活动和结果的有效性,提高实验室γ放射性核素检测的能力。方法 对影响全国γ放射性核素考核结果的相对偏差、准确度、精确度、相对合成不确定度进行统计分析。结果 本实验室2018—2020年全国γ放射性核素考核上报结果均满足合格要求,其中2019年被评为优秀,2018—2020年11个测量结果相对偏差最大为18.01%,2018年|Z_检验|≤1、U_检验≤2.58,2019年|Z_检验|≤1、U_检验≤1,2020年U_检验≤1、U_rel≤20%。结论 本实验室采用的放射性核素γ能谱分析方法正确,检测数据准确、可靠。     

NaI(Tl)γ能谱谱线分析技术的研究

目的 提高NaI(Tl)γ能谱的测量精度,拓展其应用范围。方法 针对NaI(Tl)γ能谱的谱型特征,利用权重最小二乘法进行解谱。结果 介绍了低本底NaI(Tl)γ能谱仪的常用解谱方法,着重介绍了权重最小二乘法(WLSQ)的原理和算法,并在Matlab平台下编程。结论 同一样品谱利用WLSQ求解的结果与HPGe谱仪测量的结果的偏差小于10%。     

核电站周边和敏感地区食品放射性调查方案概述

目的 建立核电站周边和敏感地区食品中放射性核素调查方案。方法 根据既往对国内外核试验监测和对苏联切尔诺贝利核电站事故监测的实践经验,参照国家相关标准,建立了核事故应急监测调查方案。结果 提出了核电站和敏感地区放射性调查的项目,采样点的布局,样品的采集与处理和放射性核素γ能谱定量分析方法,简述了本次调查的质量保证方法。结论 本文提出的核电站周边和敏感地区食品放射性调查方案,可以作为核事故应急放射性核素监测的技术导则使用。     

超声测定人体胸壁厚度及组织成分在内照射监测中的应用

目的 采用医疗诊断超声成像技术对参与放射性操作的工作人员胸壁厚度及组织成分进行精确测量,减小人体胸壁厚度、组织成分不确定引起的人员内照射测量及剂量估算的误差。方法 采用超声成像技术对26人进行定位测量,采集超声图片,分析几何胸壁厚度和肌肉、脂肪含量。结果 超声图片分析结果结合肌肉等效胸壁厚度公式,通过计算,将几何胸壁厚度转化为肌肉等效胸壁厚度,归一胸壁不同组织对肺内出射的不同能量的γ、X射线的阻挡作用。结论 当内照射测量对象为发射低能光子的核素时,该方法较传统的公式计算法更精确,将减少肺部计数器探测效率±20%的误差。能极大减小活体测量工作人员肺内放射性核素滞留量、估算内照射剂量的系统误差。     

Contamination of individuals by radon daughters: a preliminary study

Body radon daughter contamination reflects relative individual respiratory exposures to radon daughters; counts can be related both to household radon levels and to lung cancer risk factors such as sex and tobacco smoking. Radon daughters were counted by gamma spectroscopy from 180 adult residents of eastern Pennsylvania. A seven-position, 35-min scan was conducted in a mobile body counter, generally during afternoon or evening hours. Track-etch detectors for household radon were distributed, and were recovered from 80% of the subjects. Over 75% of the population had environmentally enhanced radon daughter contamination. House radon levels were strongly related, as anticipated, to radon daughter contamination in the 112 subjects for whom both sets of measurements were available (p less than .001); basement measurements were as strongly related to personal contamination as were living area measurements; bedroom measurements were slightly more strongly correlated. Both sex (p less than .02) and cigarette smoking (p less than .01) significantly modified the relationships, after nonlinear adjustment for travel times. Using a logarithmic model, a given house living-area radon level was associated in females with body contamination by radon daughters 2-3 times that in males. Nonsmokers had 2-4 times higher levels of contamination than smokers. Results are for the total of internal and external contamination, these being highly correlated in preliminary experiments. Time usage and activity patterns of the subjects are believed to be important in explaining these findings, and may become important variables in radon risk assessment.     

Use of epidemiological data and direct bioassay for prioritization of affected populations in a large-scale radiation emergency

Following a radiation emergency, evacuated, sheltered or other members of the public would require monitoring for external and/or internal contamination and, if indicated, decontamination. In addition, the potentially-impacted population would be identified for biodosimetry/bioassay or needed medical treatment (chelation therapy, cytokine treatment, etc.) and prioritized for follow-up. Expeditious implementation of these activities presents many challenges, especially when a large population is affected. Furthermore, experience from previous radiation incidents has demonstrated that the number of people seeking monitoring for radioactive contamination (both external and internal) could be much higher than the actual number of contaminated individuals. In the United States, the Department of Health and Human Services is the lead agency to coordinate federal support for population monitoring activities. Population monitoring includes (1) monitoring people for external contamination; (2) monitoring people for internal contamination; (3) population decontamination; (4) collecting epidemiologic data regarding potentially exposed and/or contaminated individuals to prioritize the affected population for limited medical resources; (5) administering available pharmaceuticals for internal decontamination as deemed necessary by appropriate health officials; (6) performing dose reconstruction; and (7) establishing a registry to conduct long-term monitoring of this population for potential long-term health effects. This paper will focus on screening for internal contamination and will describe the use of early epidemiologic data as well as direct bioassay techniques to rapidly identify and prioritize the affected population for further analysis and medical attention.     

Test models for hygienic handrub and hygienic handwash: the effects of two different contamination and sampling techniques.

Two methods for artificial contamination of hands and two sampling techniques to recover the test organisms were compared for their effects on the results of two post-contamination hand treatments: a handrub with two portions of 3 ml of 2-propanol 60% v/v for 1 min, and a handwash with liquid soap 20% w/v for 1 min followed by a 15 s rinse. The two contamination methods involved a short immersion of the hands (up to the middle of the mid-hand) in a suspension of the test organism followed by either air-drying (3 min) or drying by rubbing the hands' vigorously against each other (3 min) in a standardized way. The two sampling techniques consisted of rubbing the fingertips in either 10 ml trypticase soy broth (TSB) against the bottom of a Petri dish; or 100 ml TSB against glass beads contained in a bowl. Sixteen volunteers were randomly allotted to four blocks of four. They carried out the four possible combinations of two treatments and two contamination methods in a series of four tests arranged in a Latin-square design. In addition, the two sampling techniques were compared with each other concurrently by sampling of the right and left hand each with a different one of the two techniques. The alcoholic handrub reduced the release of test organisms significantly (2P less than 0.005) more effectively, by 1.1-1.3 x log10, than did the handwash with liquid soap, regardless of the contamination or sampling method. Whereas the two recovery techniques yielded virtually identical results in corresponding situations, the method of artificial contamination affected the mean reduction factors, strongly.(ABSTRACT TRUNCATED AT 250 WORDS)     

种子包衣剂多·克·福经皮染毒对大鼠的亚急性毒性

目的　检测多·克·福种衣剂经皮肤接触的亚急性毒性反应。方法　Wistar大鼠经皮染毒 ,剂量为 2 15 ,86 ,4 3mg/kg。观察体重、血常规及血液生化指标、脏体比值的变化。结果　高、中剂量组体重明显低于对照组。高剂量组白细胞总数明显高于对照组。结论　经皮接触多·克·福种衣剂对大鼠机体会产生一定损害。     

Cerebral blood flow and mental processes in schizophrenia.

The patterns of cerebral blood flow associated with three syndromes of schizophrenic symptoms are compared with the loci of cerebral activation in normal subjects during the performance of mental processes implicated in the three syndromes. The psychomotor poverty syndrome, which has been shown to involve a diminished ability to generate words, is associated with decreased perfusion of the dorsolateral prefrontal cortex at a locus which is activated in normal subjects during the internal generation of words. The disorganization syndrome, which has been shown to involve impaired suppression of inappropriate responses (eg in the Stroop test), is associated with increased perfusion of the right anterior cingulate gyrus at a location activated in normal subjects performing the Stroop test. The reality distortion syndrome, which evidence suggests arises from disordered internal monitoring of activity, is associated with increased perfusion in the medial temporal lobe at a locus activated in normal subjects during the internal monitoring of eye movements.     

Design and operation of a whole-body monitoring system for the Goiania radiation accident

With as many individuals involved in the Goiania 137Cs accident who had high levels of internal contamination, it was necessary to improvise a whole-body counter installation in loco. The in-vivo counting system was located in a 4.0 X 3.5 X 3.5-m room, where seven layers of 2-mm lead sheets with dimensions of 2.0 m X 1.0 m were overlaid on the floor at loci that were equidistant from the walls. A 20-cm diameter NaI (Tl) detector was installed at a height of 2.05 m above the floor at the center of the room. The detector was shielded and collimated with 5 cm of lead. The enormous amounts of activity in the subjects required the detector to be positioned at a height of 2.05 m. Subjects were required to wear disposable clothing and lie on a reclining, fiberglass chair. Counting time for the subjects was 2 min (live-time). The minimum detectable 137Cs activity for this counting time was 7.3 kBq* (0.05 significance level). Besides the accident victims, all individuals who had direct or indirect contact with contaminated people or areas were also monitored. More than 300 people of both sexes, with ages varying from a few months to 72 y, were measured for whole-body radioactivity. The observed activities ranged from less than the minimum detectable activity (MDA) to 59 MBq.     

林业集,运材作业工人全身振动的测试及卫生学评价

为了解林业作业工人全身振动的职业危害现状，运用先进的振动测试技术和手段对从事林业集、运材作业的工人进行了全身振动测试。三轴向振动测试结果表明，３种类型集、运材车辆Ｚ轴振动强度全部超过了ＩＳＯ２６３１的４小时暴露极限值；水平轴向振动强度因车型而异，集材拖拉机Ｘ和Ｙ轴、运材汽车Ｘ轴振动强度较大，均接近或超过ＩＳＯ２６３１的８小时暴露极限值；而运材汽车Ｙ轴振动强度较低，但也超过了ＩＳＯ２６３１的８小时疲劳－减效界限值     

Is manganese an essential supplement for parenteral nutrition?

PURPOSE OF REVIEW: To summarize the role of the essential trace element, manganese, its potential toxicity, monitoring methods and dosage recommendations for nutrition support. RECENT FINDINGS: Parenteral nutrition usually contains manganese as part of a fixed concentration multiple trace element supplement. Recent literature identifies potential problems in this approach and reports toxic symptoms resulting from hypermanganesaemia in paediatric and long-term home patients. Elimination by the hepatobiliary system is frequently impaired, and parenteral administration bypasses the regulatory mechanisms of homeostasis. Together with occasional oral intake and product contamination, this can lead to brain accumulation and neurotoxicity, with individual responses to supplementation difficult to predict. Regular monitoring is recommended, but plasma and serum analyses are poor indicators of body stores. Whole blood concentrations are more accurate and correlate with signal intensity of MRI. We have identified a need for individual trace element additives to be more widely available and for multitrace element products to be reformulated. There is now a persuasive argument for not routinely adding manganese to parenteral nutrition admixtures. SUMMARY: High intravenous doses of manganese can lead to neurotoxicity. Current dosage guidelines and trace element formulations need revision. Frequent monitoring to identify tissue accumulation is recommended for paediatric and long-term home parenteral nutrition patients.     

Development and evaluation of a real-time FRET probe based multiplex PCR assay for the detection of prohibited meat and bone meal in cattle feed and feed ingredients

A novel real-time fluorescent multiplex polymerase chain reaction (PCR) assay for detecting and discriminating between bovine, ovine, and caprine contaminates in cattle feed was developed that simultaneously performs quality control monitoring on both the DNA extraction process and the level of PCR inhibition in the final DNA extract in a single PCR run. The assay used a single set of primers and two sets of FRET probes targeting the ruminant-specific mitochondrial cytochrome b gene. An internal control PCR reaction targeting a region of the chloroplast RNA polymerase beta-subunit (rpobeta) gene, which is conserved among plants, was incorporated into the ruminant multiplex PCR reaction in order to both monitor the DNA extraction method and to test for the presence of PCR inhibitors. The detection limit for bovine and ovine contaminates was evaluated over a period of two sets of six trials on 15 different types of cattle feed and feed ingredients spiked with known concentrations of bovine meat and bone meal (BMBM) and lamb meat and bone meal (LMBM). The assay was able to detect 0.05% w/w BMBM contamination and 0.1% w/w LMBM contamination in all samples of cattle feed and feed ingredients tested.     

Microbial contamination of arterial infusions used for hemodynamic monitoring: a randomized trial of contamination with sampling through conventional stopcocks versus a novel closed system

Arterial catheters are now commonly used to monitor blood pressure and obtain blood samples for arterial blood gas and other laboratory determinations. Stopcocks inserted into the pressure monitoring circuit have been the primary means of obtaining blood from arterial catheters. However, these stopcock systems have been associated with nosocomial contamination and bacteremias. Because of the problems of bacterial contamination and blood wasting with the stopcock sampling systems, we compared the frequency and extent of contamination of external sampling ports and the monitoring tubing fluid in stopcocks with that of a novel closed needle-sampling system (Lab-Site, Migada Ltd, Rehovot, Israel), incorporated into pressure monitoring tubing (Abbott Laboratories Inc., North Chicago, Illinois). We found that use of the novel sampling system resulted in significantly fewer episodes of internal bacterial contamination of the arterial monitoring line (7%) than did the use of a stopcock system (61%). External contamination of the sampling port was also lower in the novel system (8%) than in the stopcock system (37%). This suggests that the closed system may reduce the risk of nosocomial infections in patients requiring arterial pressure monitoring.