生物无机化学实验室的“三废”绿色化处理措施研究

生物无机化学实验中不可避免地产生的某些有毒气体、液体和固体,都需要及时排弃,特别是某些剧毒物质,如果直接排出就可能污染周围空气和水源,使环境污染,损害人体健康。因此,生物无机化学实验室内必须对废液和废气、废渣处理后才可排弃。     

细菌类生物制品生物危害程度分类探讨

以卫生部《人间传染的病原微生物名录》为基础,根据细菌类生物制品生产用菌(毒)种的特点以及该病原微生物的传染性、感染后对个体或者群体的危害程度,将生物制品生产用菌(毒)种中结核杆菌与肉毒梭菌分为第二类,灭活疫苗、组分疫苗、类毒素生产用菌(毒)种为第三类;活疫苗与微生态活菌制剂中除芽孢菌与条件致病菌为第三类外,其他为第四类。     

虚拟生物实验室实例

虚拟生物实验室在生物课程资源中有巨大并且尚未开发的潜力。它对于不同级别学生的学习都是有利的。介绍了虚拟生物实验室的一些实例。并展望了其应用前景。     

细菌生物被膜与食品生物危害

食源性病原菌生物被膜是威胁食品安全的一个重大隐患。生物被膜一旦在食品加工过程中形成,易引起相当严重的交叉污染和加工后污染,产生极大危害,从而导致一系列严重的健康问题。本文就食源性病原菌生物被膜的分布、形成机制以及防治措施进行了综述。     

美国医院微生物学实验室在处理生物恐怖事件中的作用

2001年9月和10月的炭疽暴发事件中,很多医院临床微生物学实验室对粉末及各种环境中的物质进行检验。自“911”事件后的炭疽暴发,即组成了实验室应急反应网络(1abomtoryresI)onsenetW0rk,LRN),但是很多实验室不熟悉或全然不知其在实验室应急反应网络中的作用。由炭疽发生的经验可知,微生物学工作者所询问的一个主要问题是：“如     

生物实验室

将原来“技术与方法”栏目改为“生物实验室”。刊发的文章主要侧重于从实验室科研人员的角度,深度报道使用某种仪器设备进行实验后所获得的最新结果,交流由此衍生出的新技术新方法。希望此栏目能够成为架起实验室与实验室,以及实验室与仪器生产商之间联系的桥梁。     

生物实验室

将原来“技术与方法”栏目改为“生物实验室”。刊发的文章主要侧重于从实验室科研人员的角度,深度报道使用某种仪器设备进行实验后所获得的最新结果,交流由此衍生出的新技术新方法。希望此栏目能够成为架起实验室与实验室,以及实验室与仪器生产商之间联系的桥梁。     

研究型生物实验室的管理

随着科学研究的作用越来越突出,国家和社会在科技方面的投入也日益增加,科研条件已得到极大的改善。实验室是进行科学研究、取得科研成果、培养科研人才的场所。如何使实验室健康、高效地运转是一个系统的工程,也是一个值得科研工作者关注、探讨的问题。我们根据生物实验室的特点,讨论了生物实验室仪器的使用与管理、人员管理、实验室安全、废物的回收和处理等问题。     

生物实验室

将原来“技术与方法”栏目改为“生物实验室”。刊发的文章主要侧重于从实验室科研人员的角度,深度报道使用某种仪器设备进行实验后所获得的最新结果,交流由此衍生出的新技术新方法。希望此栏目能够成为架起实验室与实验室,以及实验室与仪器生产商之间联系的桥梁。     

生物实验室

将原来“技术与方法”栏目改为“生物实验室”。刊发的文章主要侧重于从实验室科研人员的角度,深度报道使用某种仪器设备进行实验后所获得的最新结果,交流由此衍生出的新技术新方法。希望此栏目能够成为架起实验室与实验室,以及实验室与仪器生产商之间联系的桥梁。     

Environmental health research on hazards in the home and the duty to warn

When environmental health researchers study hazards in the home, they often discover information that may be relevant to protecting the health and safety of the research subjects and occupants. This article describes the ethical and legal basis for a duty to warn research subjects and occupants about hazards in the home and explores the extent of this duty. Investigators should inform research subjects and occupants about the results of tests conducted as part of the research protocol only if the information is likely to be accurate, reliable, and medically useful. Investigators should warn subjects and occupants about hazards they happen to discover while they are in the home, if a reasonable person would warn the subjects and occupants about those hazards. Investigators should not report illegal hazards discovered in the home to the authorities, unless those hazards constitute abuse or neglect of children or mentally disabled people living in the home. When investigators decide to warn research subjects and occupants about hazards in the home, they should take some steps to help them make effective use of this information, such as providing additional counselling or making a referral for remediation or medical treatment. Investigators should discuss these issues with research subjects during the informed consent process.     

Enzyme-based strategy for toxic waste treatment and waste minimization

The increasing amounts of pesticides used throughout the world, as well as the increasingly stringent governmental regulations concerning waste disposal, mandates improved techniques of waste disposal and minimization. In this article, parathion hydrolase, an enzyme with proven effectiveness at hydrolyzing organophosphates, was used to treat a cattle dipping liquid containing the pesticide, coumaphos, which is used to kill a disease-causing tick. Waste is generated from this process when a toxic dechlorination product of coumaphos, potasan, accumulates to concentrations hazardous to the cattle. This pesticide system was used as a model to demonstrate how enzyme technology can be applied to waste treatment and minimization. Kinetic experiments showed that the hydrolysis of the two organophosphate substrates can be modeled as first-order reactions with identical rate constants. It was further shown that the enzyme is capable of hydrolyzing only dissolved substrates. Because of the eightfold greater solubility of potasan than coumaphos (16.9 vs. 2.2 mumol/L), it was possible to utilize the enzyme to hydrolyze potasan selectively. Thus, by limiting the amount of enzyme, it is possible to remove potasan selectively to extend the lifetime of the cattle dipping liquid, thereby reducing the amount of waste generated. Based upon experimental results, a mathematical model describing the system was developed and verified. The mathematical model was then used to simulate the ability of the enzyme to hydrolyze the total amount of organophosphates, and to degrade selectively all of the toxic potasan without a significant loss of coumaphos.     

Isolation of a microbial consortium from activated sludge for the biological treatment of food waste

The bacterial community in the activated sludge of a local wastewater treatment plant was studied in an effort to understand and exploit the metabolic versatility of microorganisms for the efficient biological treatment of food waste. Microorganisms capable of and efficient in degrading domestic food waste were screened based on their ability to produce areas of clearing on selective media containing protein, fat, cellulose and starch. Nine microbial species belonging to the genera Flavobacterium, Pseudomonas, Micrococcus, Aeromonas, Xanthomonas, Vibrio and Sphingomonas were found to degrade all components of food waste. These bacteria were added to domestic wastewater and shown to cause a 60% reduction in the biochemical oxygen demand (BOD) level of wastewater compared to a control in which no microorganisms were added. The ability of the microbial consortium to degrade domestic wastewater as evidenced by the decrease in BOD levels suggests its potential for use in the biological treatment of food waste.     

Estimating cumulative treatment effects in the presence of nonproportional hazards

Summary .   Often in medical studies of time to an event, the treatment effect is not constant over time. In the context of Cox regression modeling, the most frequent solution is to apply a model that assumes the treatment effect is either piecewise constant or varies smoothly over time, i.e., the Cox nonproportional hazards model. This approach has at least two major limitations. First, it is generally difficult to assess whether the parametric form chosen for the treatment effect is correct. Second, in the presence of nonproportional hazards, investigators are usually more interested in the cumulative than the instantaneous treatment effect (e.g., determining if and when the survival functions cross). Therefore, we propose an estimator for the aggregate treatment effect in the presence of nonproportional hazards. Our estimator is based on the treatment-specific baseline cumulative hazards estimated under a stratified Cox model. No functional form for the nonproportionality need be assumed. Asymptotic properties of the proposed estimators are derived, and the finite-sample properties are assessed in simulation studies. Pointwise and simultaneous confidence bands of the estimator can be computed. The proposed method is applied to data from a national organ failure registry.     

On corrected score approach for proportional hazards model with covariate measurement error

In the presence of covariate measurement error with the proportional hazards model, several functional modeling methods have been proposed. These include the conditional score estimator (Tsiatis and Davidian, 2001, Biometrika 88, 447-458), the parametric correction estimator (Nakamura, 1992, Biometrics 48, 829-838), and the nonparametric correction estimator (Huang and Wang, 2000, Journal of the American Statistical Association 95, 1209-1219) in the order of weaker assumptions on the error. Although they are all consistent, each suffers from potential difficulties with small samples and substantial measurement error. In this article, upon noting that the conditional score and parametric correction estimators are asymptotically equivalent in the case of normal error, we investigate their relative finite sample performance and discover that the former is superior. This finding motivates a general refinement approach to parametric and nonparametric correction methods. The refined correction estimators are asymptotically equivalent to their standard counterparts, but have improved numerical properties and perform better when the standard estimates do not exist or are outliers. Simulation results and application to an HIV clinical trial are presented.     

Simple emission-reducing measures in an open biological waste treatment plant

In the course of composting biological waste, concentrations of various thermophilic and thermotolerant microorganisms increase. Moving piles of compost results in increased emissions of Actinomycetes and fungi. The present investigation deals with the reduction of airborne microorganism emission and immission in large-scale composting plants with open piles. Simple measures were introduced in order to reduce the release of bioaerosols when turning piles and the release of dust and bioaerols at large. These measures included the sealing of turning machinery with rubber mats, the wetting of piles before and after turning and regular cleaning and wetting driveways during the dry season.Concentrations of airborne microorganisms during the summer season were determined on 5 days before and after the introduction of emission-reducing measures using the six-stage Andersen cascade sampler. The investigation showed that following the introduction of emission-reducing measures there was, at all locations, a highly significant reduction not only of all culturable indicator organisms (thermophilic actinomycetes and Aspergillus fumigatus) but also of total microorganism concentrations (p < 0,001). The introduction of the simple emission-reducing measures mentioned above, however, reduced the immission in the vicinity of the plant to such a degree that the natural background levels were reached at a distance of 150 m.