Home About us Contact
|
Home About us Contact | ||
|
|
||
Rapid Process (rapid + process)
Selected AbstractsFacile Gram-Scale Growth of Single-Crystalline Nanotetrapod-Assembled ZnO Through a Rapid ProcessEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 20 2008Jianye Li Abstract From a rapid combustion and catalyst-free method, puresingle-crystalline nanotetrapod-assembled bulk nano-ZnO was grown on a gram-scale for the first time. The gram-scale bulk nano-ZnO is synthesized from ZnO powder with great reliability and repeatability, and also a high conversion efficiency. All four arms of the nanotetrapods are cone shaped and grow in the [001] direction. The photoluminescence properties of the nanotetrapod-assembled ZnO were studied and a mechanism was suggested for the growth of the bulk nanotetrapod-assembled ZnO. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] CD2+/CD14+ monocytes rapidly differentiate into CD83+ dendritic cellsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 2 2003Di Pucchio, Tiziana Abstract Since denditric cells (DC) represent the main players linking innate and adaptive immunity, their prompt generation from blood cells would be instrumental for an efficient immune response to infections. Consistent with this, CD2+ monocytes were found to express the DC maturation marker CD83, along with acquisition of high antigen-presenting activity, after a surprisingly short time in culture. This rapid process is associated with expression of IFN-,/, genes and secretion of low levels of pro-inflammatory cytokines. Exposure of monocytes to IFN-,, but not to IL-4, induced persistence of CD2+/CD83+ cells, which were fully competent in stimulating primary responses by naive T cells. These results unravel the natural pathway by which infection-induced signals rapidly transform pre-armed monocytes into active DC. [source] Removal of Cadmium and Lead from Aqueous Solution by,Enterococcus faecium,StrainsJOURNAL OF FOOD SCIENCE, Issue 1 2010A. Topcu ABSTRACT:, Foods may be contaminated with heavy metals, which, even in small quantities, possess detrimental effects on human health. The aim of the present study was to investigate the uptake of cadmium or lead from an aqueous medium frequently found in foods, by 2,Enterococcus faecium,strains (E. faecium,EF031 and,E. faecium,M74). Also, the effects of the bacterial viability, incubation (contact) time, and pH on the binding capacities and binding stability were assessed. The results showed that both of the strains efficiently removed cadmium and lead. While EF031 removed 77.3% to 98.1% of cadmium and 66.9% to 98.9% of lead, M74 removed 53.5% to 91% of cadmium and 42.9% to 93.1% of lead throughout a 48 h incubation period at pH 5. It was found that, at 1 h, EF031 and M74 strains removed cadmium and lead, which was more than 60% of total removed cadmium and lead throughout the whole incubation period of 48 h. It suggests that the uptake of cadmium and lead by EF031 and M74 strains is a rapid process. The binding of both heavy metals increased with increasing pH of an aqueous medium and was the highest at pH 5. Also, the complexes formed between both heavy metals and bacterial cells were found to be stable. These findings indicate that,E. faecium,strains used in the study are able to bind the 2 heavy metals and may be used in the production of fermented functional foods, which will be healthy via its detoxification properties. [source] Stabilizer-free dispersion copolymerization of maleic anhydride and vinyl acetate.JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 17 2005Abstract A novel dispersion copolymerization of maleic anhydride (MAn) and vinyl acetate (VAc) without adding stabilizer is developed, which gives uniform copolymer microspheres with tunable sizes. Some principal factors affecting the microspheres, such as reaction time, monomer concentration and feed ratio, reaction media, and cosolvent, were investigated. It was found that the stabilizer-free dispersion copolymerization of MAn and VAc is a rapid process, and the particle size grows in accordance with the evolution of polymerization. The chemical composition of the copolymer microspheres was characterized by FT-IR and 13C NMR spectroscopies. Over a wide range of monomer concentrations, the microspheres can always be formed and stably dispersed, with uniform sizes ranging from 180 nm to 740 nm. The yield of copolymer microspheres reaches a maximum at 1:1 feed ratio of MAn to VAc, owing to the alternating copolymerization between the binary monomers by a known charge-transfer-complex mechanism. However, the diameter of microspheres drastically increases when MAn content is enhanced. Only some specific alkyl ester solvents, such as n -butyl acetate, isobutyl acetate, n -amyl acetate, are desirably fit for this unique stabilizer-free dispersion polymerization. Furthermore, we found that when some acetone is added as a cosolvent, the copolymer microspheres can still be formed, with much larger diameters. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3760,3770, 2005 [source] Modes and mechanisms of speciation in pteridophytes: Implications of contrasting patterns in ferns representing temperate and tropical habitatsPLANT SPECIES BIOLOGY, Issue 3 2000Christopher H. Haufler Abstract Discovering how biological diversification results in species is one of the primary challenges facing evolutionary biologists. In the ferns, evidence indicates that dissimilar speciation modes and mechanisms may differentiate some temperate and tropical groups. The Polypodium sibiricum group contains three related diploid species that all inhabit rock outcrops in temperate forests. Although differing lettle in gross leaf morphology and joined by the distinctive morphological synapomorphy of sporangiasters, these three species have an average interspecific genetic identity developed from isozymic com-parisons of only 0.460. A likely mode of speciation is that periodic glaciation pushed Po. sibiricum populations south and, with the retreat of the glaciers, southern populations persisted, evolved diagnostic traits, and ultimately erected postzygotic barriers to interbreeding. This hypothesis follows a classic allopatric speciation model and interspecific distinctions may have been reinforced through contact mediated by subsequent ice ages. In contrast, a monophyletic group of four diploid, epiphytic Pleopeltis species centered in Mexico has an isozymically-determined average interspecific genetic identity value of 0.849. In spite of this high value, these species show greater morphological discrimination than do the Polypodium species. Although the species ranges overlap, they appear to occupy ecologically discrete habitats. These Pleopeltis species may have originated through adaptation to different ecological zones and developed individual morphologies in the process. The high interspecific genetic identity values among the Pleopeltis species suggest a relatively recent and/or rapid process. These hypotheses should be tested by further biosystematic investigations and the discovery of additional monophyletic assemblages with similar patterns of speciation. [source] Health behaviours, risk-taking and conceptual changes among schoolchildren aged 7 to 19 years in semi-rural SwedenCHILD: CARE, HEALTH AND DEVELOPMENT, Issue 3 2008A. Olsson Abstract Background This study covers a broad age group (7,19 years) and includes a wide range of themes. The aim is to describe how various behaviours, complaints and conceptual changes come into play and to discuss the factors that might support or hamper the happiness and well-being of growing children and adolescents. We also discuss the implications of our findings for future prevention programmes. Methods This cross-sectional study included all schoolchildren in a semi-rural district in Sweden (2181 pupils). A structured classroom questionnaire was used but the children were also given the opportunity to describe in their own words what was important for their happiness and well-being. Results Mean response rate was 85%. Most changes in behaviour occurred between 11 and 14 years of age. Girls had a more rapid process of change than boys. Both girls and boys experienced stress in their relations with peers, parents and teachers. Gender differences in emotional support were prominent. Regardless of age and sex, all schoolchildren asked for a richer choice of leisure time activities, a place where they could meet with friends and caring teachers, parents and adults in the surrounding community. Conclusions Adolescence was perceived as a risky and problematic period not only by adults but also by the adolescents themselves. However, the perceived risks and the worries differed. While the adults mainly worried about the early onset of smoking and drug use, the schoolchildren worried about their social situation and their personal relationships. After decades of preventive programmes in Swedish schools, only modest results are seen. To be effective, future preventive programmes probably have to focus more on the conceptual world of the growing child. [source] | ||||||||||