Wood preservation hygiene and environment in the lime-light of actually

Summary Under the ?Bois plus? scheme, the CTBA is currently developing a third party certification, based on the Scrivener law, with the aim of defending the consumers' interests. At this early stage, wood preservatives and treated wood are checked for the efficacy of treatments in order to ensure the stability and security of works in buildings and civil engineering. According to the different classes of risks in service, ?Bois plus? provides the most adeguate level of protection. In the close future, the industry is planning to incorporate, with the help of the CTBA and experts, health criteria within the frame of the ?Bois plus? certification scheme. The means could beSafety indexes, which are objectives of quality for professionals.Safety indexes are concentrations of substances in wood which can be taken as safe for humans and the general environment, while still toxic for the wood pests. This attractive experience aims to make with the brandname ?Bois plus? a synonym of efficacy and safety. This approach meets the essential requirements 1, 3, 4 of the 89/106 EEC directive: mechanical resistance and stability/hygiene, health and environment/safety in use.     

Further studies of human whole-body radiofrequency absorption rates

Further studies of human whole-body radiofrequency (RF) absorption rates were carried out using a TEM-cell exposure system. Experiments were done at one frequency near the grounded resonance frequency (approximately 40 MHz), and at several below-resonance frequencies. Absorption rates are small for the K and H orientations of the body, even when grounded. For the body trunk in an E orientation, the absorption rate of a sitting person is about half of the rate for the same person standing with arms at the sides; the latter in turn is about half the rate for the same subject standing with arms over the head. Two-body interactions cause no increase in absorption rates for grounded people. They do, however, increase the absorption rates for subjects in an E orientation in free space; the largest interaction occurs when one subject is lambda/2 behind the other (as seen by the incident wave). When these results are applied to practical occupational exposure situations, the whole-body specific absorption rate does not exceed the ANSI limit of 0.4 W/kg for exposures permitted by the ANSI standard (C95.1-1982) at frequencies from 7 to 40 MHz.     

Survival of Aeromonas hydrophila and Listeria monocytogenes on fresh vegetables stored under moderate vacuum

Storage at 6.5°C under moderate vacuum effectively prevented growth of Aeromonas hydrophila on chicory endive, but had only a limited inhibitory effect on the growth of the organism on mung bean sprouts. Growth of Listeria monocytogenes on chicory endive was strongly stimulated under these conditions, whereas it was decreased on mung-bean sprouts.     

A Simple and Safe Device for Spreading Ultrathin Sections with Chloroform

A simple and safe device for spreading ultrathin sections for electron microscopy is described. The use of this device minimizes the release of chloroform vapor during section spreading.     

Rumen contents as a reservoir of enterohemorrhagic Escherichia coli

Abstract We investigatedthe role of the rumen fermentation as a barries to the foodborne pathogen, Escherichia coli O157:H7. Strains of E. coli , including several isolates of O157:H7, grew poorly in media which simulated the ruminal environment of a well-fed animal. Strains of E. coli O157:H7 did not display a superior tolerance to ruminal conditions which may facilitate their colonization of the bovine digestive tract. Unrestricted growth of E. coli was observed in rumen fluid collected from fasted cattle. Growth was inhibited by rumen fluid collected from well-fed animals. Well-fed animals appear less likely to become reservoirs for pathogenic E. coli . These results have implications for cattle slaughter practices and epidemiological studies of E. coli O157:H7.     

基于拉曼技术的单细胞生长检测方法

目的 单细胞生长检测可以更加科学地揭示微生物代谢变化的规律,为后期微生物工程应用提供指导。针对微生物生长应用于食品安全期和最佳食用期的精准检测问题,本文提出一种基于拉曼技术的单细胞生长检测方法。方法 首先,通过同步培养实验采集了枯草芽孢杆菌两个批次共900个单细胞拉曼光谱（SCRS）数据,其中600个用于训练和测试,另一批次300个用于模型验证。其次,基于主成分分析的特征关系矩阵,提出CP-SP特征评估方法以筛选SCRS特征用于模型检测。再基于XGBoost构建检测模型,并应用网格搜索和交叉验证对检测模型进行调优。最后,应用混淆矩阵、ROC曲线评估模型对细胞滞后期、对数期和稳定期的检测准确率、敏感性和特异性。结果 选用CP-SP筛选的第一、第二和第四主成分较特征贡献率前3个主成分的分类性能提高了3.1%,调优后的细胞生长检测模型测试准确率为96.0%,验证准确率为92.3%。结论 基于拉曼技术的单细胞生长检测方法能准确识别单细胞生长状态且具有较高的泛化能力,可为食品安全和保鲜制定精准调控机制提供科学指导。     

Hazards of power supplies

Electrophoretic power supplies which are not isolated from the power lines are an unnecessary lethal hazard. Their use should be discouraged.     

Survival and transfer in the human gut of poorly mobilizable (pBR322) and of transferable plasmids from the same carrier E. coli

We examined the survival of a host Escherichia coli K-12 bacterium containing two transferable plasmids (pLM2, pSL222-4) and one poorly mobilizable plasmid (pBR322), and the transfer of these three plasmids to endogenous bacteria in the human intestinal tract. The survival of this plasmid-carrying host organism in four human volunteers was 3.5 to 6 days at recovery rates of 10^?1 to 10^?4. This finding was similar to our previous survival data on the same organism bearing a single plasmid. The K-12 strain appeared to be under a strong selective disadvantage in the human gut, since, even when bearing a tetracycline-resistant plasmid, its titer did not increase despite the administration of tetracycline. Studies of transferability showed that, while the transfer-depressed incFII plasmid pSL222-4 transferred at a frequency of 10^?1 in culture, its transfer in the human gut was much less frequent. The number of new recipients per donor cell ingested was about 10^?5, which included new recipients arising by multiplication. The recovery of pSL222-4 transcipients was enhanced by the administration of tetracycline on day 6. Neither the transfer-repressed, broad host range incP plasmid pLM2, nor the plasmid pBR322, could be detected in any endogenous host bacteria. Using the transfer and mobilization frequencies obtained in culture and the number of new recipients of pSL222-4 in the intestinal tract, we estimated that any in vivo mobilization of pBR322 to a new recipient could not occur at a frequency higher than 10^?12.     

Assessment of environmental contamination associated with a mammalian cell transformation assay

Summary To estimate worker exposures to, and environmental contamination from, test chemicals and organic solvents used in an in vitro assay to assess the carcinogenic potential of chemicals, sodium fluorescein, a noncarcinogenic fluorescent material, was dissolved in tissue culture medium used to maintain early passage hamster embryo cells. Personal and environmental samples were taken over a 14-d period. The assay was performed according to standard procedures in a ventilated glove box or laminar flow safety cabinet. Considerably more than 99% of the chemical contamination found was recovered from the interiors of the glove box and hood and from disposable equipment. Contamination outside the containment units (less than 1 μg) resulted from intralaboratory transport of chemicals, treated cultures, and contaminated equipment. We conclude that the standard operating practices and procedures provided adequate safeguards for personnel and the environment. Research sponsored by the National Cancer Institute under Contract N01-CO-75380, with Litton Bionetics, Inc.