Technical basis for EPA's proposed regulation on the cleanup of sites contaminated with radioactivity

The U.S. Environmental Protection Agency is proposing a regulation for the protection of the public from radioactive contamination at sites that are to be cleaned up and released for public use. The rule will apply to sites under the control of Federal agencies, and will impose limits on radiation doses to individuals living or working on a site following cleanup; it will thereby provide site owners and managers with uniform, consistent cleanup criteria for planning and carrying out remediation. This paper presents an overview of EPA's approach to assessing some of the beneficial and adverse effects associated with various possible values for the annual dose limit. In particular, it discusses the method developed to determine how the choice of cleanup criterion affects (1) the time-integrated potential numbers of non-fatal and fatal radiogenic cancers averted among future populations, (2) the occurrence of radiogenic cancers among remediation workers and the public caused by the cleanup process itself, and (3) the volumes of contaminated soil that may require remediation. The analytic methods described here were used to provide input data and assumptions for the Regulatory Impact Analysis (RIA) that supports the proposed regulation; the RIA also considered non-radiological benefits and costs (i.e., public health, economic, and ecological) of the standards.     

Solid-phase extraction cleanup for ivermectin in liver tissue

Extraction of liver tissue with organic solvent produces coextractants with compounds of interest. The solid-phase extraction (SPE) cleanup of liver tissue developed for ivermectin removes nonpolar coextractants. Liver extract that has been reduced to dryness is reconstituted in 0.5 mL acetonitrile. The mixture is passed through 0.1 g C18 SPE column, and the eluate is collected. The column is eluted further with 2 mL acetonitrile. Combined eluates are derivatized with 1-methylimidazole and trifluoroacetic anhydride, and the ivermectin derivative is determined by liquid chromatography with fluorescence detection.     

新型生物反应墙原位修复石油烃污染地下水

以功能微生物、泥炭和粗砂为填充介质设计新型生物反应墙,研究了反应墙对地下水中石油烃污染物的修复效果与机理.结果表明:运行期内生物反应墙修复效果良好,苯系物、萘系物及菲去除率为83.6%～99.85%,其中71.23%～99.71%在墙体前半部分被去除.泥炭介质和功能微生物能够稳定发挥对污染物的吸附与降解功能,32.63%～77.98%的BTEX和97.14%～99.81%的目标PAHs被泥炭吸附去除;18.96%～50.98%的BTEX和已吸附于泥炭上的大部分石油烃污染物均显示被生物降解.微生物对污染物的降解可有效延长泥炭的吸附寿命,泥炭对功能微生物的营养供给可使反应墙内长期保持较高的功能微生物数量,每克干介质约含有3.46×106～6.16×109个.因此新型生物反应墙原位修复石油烃污染地下水是可行的.     

In situ detection of apoptosis at sites of chronic bacterially induced inflammation in human gingiva

Apoptosis is a key phenomenon in the regulation of the life span of terminally differentiated leukocytes. Human gingiva represents an established model to study immune responses to bacterial infection. In this investigation, we used the TUNEL (terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling) technique to evaluate presence and topographic location of apoptosis-associated DNA damage in human gingival biopsies along with the expression of the p53 and Bcl-2 apoptosis-regulating proteins. Qualitative data analysis showed high densities of cells expressing DNA damage and p53 both within the epithelial attachment to the tooth and in the perivascular infiltrate (infiltrated connective tissue [ICT]) immediately underlying the site of chronic bacterial aggression. Topographic consistency between DNA damage- and p53-positive cells was consistently observed. Quantitative analysis of the ICT showed mean densities of DNA damage- and p53-positive cells of 345 +/- 278 and 403 +/- 182 cells/mm2, respectively. Numerical consistency was confirmed by multivariate regression analysis: densities of DNA damage-positive cells were significantly predicted by densities of p53-positive cells (P = 0. 001, r2 = 0.84). In the ICT, cells displaying biotinylated DNA nicks were 3.8% +/- 2.7% of total cellularity, while p53- and Bcl-2-positive cells represented 4.4% +/- 1.7% and 15.4% +/- 6.7% of total cells, respectively. It is suggested that p53 expression associated with DNA damage is a prevalent phenomenon in chronically inflamed human gingiva, and that apoptosis may be a relevant process for the maintenance of local immune homeostasis at sites of chronic bacterial challenge in vivo.     

Do recorded doses overestimate true doses received by Chernobyl cleanup workers? Results of cytogenetic analyses of Estonian workers by fluorescence in situ hybridization

Immunoscreening of an expression library constructed with Toxoplasma gondii tachyzoite mRNA with sera from toxoplasmosis-positive humans has led to the identification of a new parasite antigen. Sequence analysis of the gene encoding this antigen allowed the calculation of the theoretical molecular mass (25,857 Da) and showed that the protein contains a putative signal sequence. The C-terminal region contains two hydrophobic regions, the last of which has the characteristics of a membrane-spanning domain. When the protein was heterologously expressed in E. coli and tested by Western blot, it reacted with the human sera originally used for screening. The new antigen also reacted with a monoclonal antibody raised against the entire parasite. Ultrastructural analysis showed that the protein is localized in the dense granules. After host cell invasion, the protein is secreted into the vacuolar network, the parasitophorous vacuole membrane, and into extensions protruding in the cytoplasm. Therefore, it is suggested to designate this new dense granule protein GRA7, following the established nomenclature for this protein family.     

Method development for trace analysis of heteroaromatic compounds in contaminated groundwater

An analytical method providing high sensitivity (limit of quantitation of 50 ng/l) with acceptable reproducibility (mean R.S.D. 19%) has been developed for determining heteroaromatic compounds in creosote-contaminated groundwater. The best technique (highest recovery and reproducibility) found between liquid-liquid extraction using either dichloromethane, diethyl ether or pentane and solid-phase extraction with reversed-phase bonded columns, was the classical liquid extraction with dichloromethane from weak basic solutions and GC-MS (selective ion monitoring) analysis of concentrated extracts.     

A method for identifying splice sites and translational start sites in eukaryotic mRNA

History of the IInd Gynaecological and Obstetric Clinic of 1st Faculty of Medicine, Charles University in Prague is recorded here from its establishment in 1920 to the end of World War II. The activities of the Clinic are depicted in characterization of prominent personalities who worked here in this period. The characterization is focussed mostly on head physicians and their clinical, pedagogical and scientific activities and their works published.     

增材制造用金属粉末原材料检测技术

增材制造技术又称3D打印,自提出以来受到国内外学者的广泛关注。金属材料的增材制造相比于其他材料难度较大,对于原材料、工艺控制等方面的要求更严苛。针对国内的增材制造用粉末生产及使用情况,本文从金属粉末粒度分布、形貌和流动性检测方法三个方面,结合实际生产、检测的经验,分别讨论了各种粉末检测方法对于增材制造技术的适用性和可行性。     

航空用钛合金阻燃技术

综述了航空用钛合金的阻燃技术和阻燃机理,介绍了国内外阻燃技术的研究和应用状况。     

推荐两项铜加工节能减排工艺

在简述我国节能减排的形势基础上推荐了两项铜加工的节能减排工艺:铜管坯连铸工艺和铜板带的连铸连轧工艺,并对其节能减排的效果作了定量的分析。     

钨湿法冶炼新工艺技术的应用

简述了郴州钻石钨制品有限责任公司在钨湿法冶炼新工艺技术方面的应用，并对钨湿法冶炼工艺今后的发展提出了建议。     

The nature of the changes in the immunity of the women who worked in the cleanup of the sequelae of the accident at the Chernobyl Atomic Electric Power Station and were evacuated from the radioactively contaminated area

During examination of 37 women taking part in elimination of consequences of Chernobyl's disaster was revealed, that complex of disaster factors action resulted the formation of disbalance in the system of immunocompetence cells and caused the oppression of functional activity of neutrophils. In 110 women living on the radioactive contaminated zone (5-40 Ci/km) the phenomena of the secondary immunodeficiency in the form of defeat as cellular as humoral factors of immunity and nonspecific resistance system was diagnosed.