活性炭—超滤组合工艺处理南方微污染原水的研究

研究了活性炭—超滤组合工艺对主要污染物的去除效果,以及超滤膜污染情况。组合工艺出水浊度一般为0.01~0.03 NTU,粒径大于2μm的颗粒数低于10个/mL。组合工艺对CODMn、UV254和TOC的去除率分别为47%、88%和60%,其中炭吸附起主要作用,分别占39%、86%和57%。总细菌数和异养菌平板计数(HPC)在炭吸附池出水中分别为1~1 300 CFU/mL和190~2 880 CFU/mL,而其在超滤出水中分别为0~5 CFU/mL和0~40 CFU/mL,这显著提高了微生物安全保障水平。浮游动物能穿透炭砂滤层,但超滤对浮游动物有非常好的截留效果,出水中偶有检出轮虫,最大为2.5个/100 L。超滤膜污染为由金属离子和有机物造成的综合性污染,金属离子包括Fe3+、Al3+等高价离子,以及Ca2+、Mg2+等二价离子;有机物主要为烷烃和芳香烃等。活性炭—超滤组合工艺非常适合于我国南方地区高温高湿气候,以及季节性有机污染和微生物污染的水质特征。     

Teamwork and Organizational Innovation: The Moderating Role of the HRM Context

Evidence is accumulating on the role of teams in shaping a variety of business outcomes, but our knowledge on the effect of teamwork on organizational innovation is still evolving. This study examines whether the extent to which two staff groups are organized in teams (production staff and management/administrative staff) affects organizational innovation and whether human resource management (HRM) systems, which can be of facilitating or constraining nature, enhance the teamwork/innovation relationships. Hypotheses were tested with lagged and longitudinal data derived from 18 to 45 organizations from the UK manufacturing sector. Results suggest that the more widespread the use of teamwork in organizations, the higher the level of organizational innovation. Furthermore, this effect depends, particularly for production teams, on the overall quality of the HRM systems that exist in their organizations. Teamwork/innovation relationships are further moderated (for management and administrative teams) by an HRM practice that provides teams with time for thoughtful reflection. Thus, HRM systems can be of more or less facilitating or constraining nature for teams in organizations.     

Deficiency of adenosine deaminase not associated with severe combined immunodeficiency

The 12-year-old Kung ("Bushman') boy from South West Africa who has marked deficiency of red cell adenosine deaminase has been found to have 2 to 3% of enzyme activity in red blood cells, 10 to 12% in leukocytes, and 10 to 30% in cultured fibroblasts. The enzyme has ADA 1 electrophoretic mobility: SV40 transformation of cultured fibroblasts caused a decrease of "tissue ADA' and an increase in "red cell ADA' isozymes. A battery of investigations revealed that the child has normal humoral and cellular immunity. A family study showed that a sibling had the same level of red cell ADA and the parents had intermediate levels. Studies of the Kung population from which the child comes have shown that the allele responsible for the condition, and which we designate ADA8, is polymorphic.     

Formation of a mosaic of neuronal activity from microfoci of excitation in rat cerebral cortex

Responses of several neurons from area 17 in the rat visual cortex to illumination with round spots of growing size were recorded. The size and shape of receptive fields of the neurons were determined. When the spot was placed into the central part of the receptive fields of neurons situated along one vertical run, distribution analysis of excited, inhibited, and non-responding neurons here showed that microlocus of excitation was being formed in the middle layers of the visual cortex. As the spot became larger, the neuronal ensemble "grew" up to a certain critical size, beyond which the microlocus of excitation divided, and the mosaic of neuronal ensembles began to form reaching maximal clear-cutness of diffuse illumination of the eye.     

Formation and enhanced biocidal activity of water-dispersable organic nanoparticles

Water-insoluble organic compounds are often used in aqueous environments in various pharmaceutical and consumer products. To overcome insolubility, the particles are dispersed in a medium during product formation, but large particles that are formed may affect product performance and safety. Many techniques have been used to produce nanodispersions-dispersions with nanometre-scale dimensions-that have properties similar to solutions. However, making nanodispersions requires complex processing, and it is difficult to achieve stability over long periods. Here we report a generic method for producing organic nanoparticles with a combination of modified emulsion-templating and freeze-drying. The dry powder composites formed using this method are highly porous, stable and form nanodispersions upon simple addition of water. Aqueous nanodispersions of Triclosan (a commercial antimicrobial agent) produced with this approach show greater activity than organic/aqueous solutions of Triclosan.     

Independence of serum lipid levels and dietary habits. The Tecumseh study

Serum cholesterol and triglyceride levels were correlated with dietary habits of 4,057 adult participants in a prospective epidemiologic survey of cardiovascular disease in Tecumseh, Mich. Frequency of consumption of 110 different food items was determined for each participant and average weekly consumption rates of foods high in fat, sugar, starch, and alcohol content were calculated. Frequency of consumption of these nutrients was then correlated with serum cholesterol and triglyceride levels of individual subjects. Serum cholesterol and triglyceride values were not positively correlated with selection of dietary constituents. Positive correlations between serum lipid levels and adiposity were statistically significant. These findings suggest that serum cholesterol and triglyceride levels among Americans are more dependent on degree of adiposity than on frequency of consumption of fat, sugar, starch, or alcohol.     

Chemical Ecology of Cave-Dwelling Millipedes: Defensive Secretions of the Typhloiulini (Diplopoda,Julida, Julidae)

Cave animals live under highly constant ecological conditions and in permanent darkness, and many evolutionary adaptations of cave-dwellers have been triggered by their specific environment. A similar “cave effect” leading to pronounced chemical interactions under such conditions may be assumed, but the chemoecology of troglobionts is mostly unknown. We investigated the defensive chemistry of a largely cave-dwelling julid group, the controversial tribe “Typhloiulini”, and we included some cave-dwelling and some endogean representatives. While chemical defense in juliform diplopods is known to be highly uniform, and mainly based on methyl- and methoxy-substituted benzoquinones, the defensive secretions of typhloiulines contained ethyl-benzoquinones and related compounds. Interestingly, ethyl-benzoquinones were found in some, but not all cave-dwelling typhloiulines, and some non-cave dwellers also contained these compounds. On the other hand, ethyl-benzoquinones were not detected in troglobiont nor in endogean typhloiuline outgroups. In order to explain the taxonomic pattern of ethyl-benzoquinone occurrence, and to unravel whether a cave-effect triggered ethyl-benzoquinone evolution, we classed the “Typhloiulini” investigated here within a phylogenetic framework of julid taxa, and traced the evolutionary history of ethyl-benzoquinones in typhloiulines in relation to cave-dwelling. The results indicated a cave-independent evolution of ethyl-substituted benzoquinones, indicating the absence of a “cave effect” on the secretions of troglobiont Typhloiulini. Ethyl-benzoquinones probably evolved early in an epi- or endogean ancestor of a clade including several, but not all Typhloiulus (basically comprising a taxonomic entity known as “Typhloiulus sensu stricto”) and Serboiulus. Ethyl-benzoquinones are proposed as novel and valuable chemical characters for julid systematics.     

Morphology and mechanical properties of polypropylene/polyamide 6 nanocomposites prepared by a two‐step melt‐compounding process

Polypropylene/polyamide 6 blends and their nanocomposites with layered silicates or talc were prepared in a melt‐compounding process to explore their mechanical performance. The thermomechanical behavior, crystallization effects, rheology, and morphology of these materials were studied with a wide range of experimental techniques. In all cases, the inorganic filler was enriched in the polyamide phase and resulted in a phase coarsening of the polypropylene/polyamide nanocomposite in comparison with the nonfilled polypropylene/polyamide blend. The mechanical properties of these nanoblends were consequently only slightly better than those of the pure polymers with respect to the modulus, whereas the impact level was below that of the pure polymers, reflecting the heterogeneity of the nanoblend. Polymer‐specific organic modification of the nanoclays did not result in a better phase distribution, which would be required for better overall performance. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 283–291, 2006