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Polymeric compounds in activated sludge supernatant -- Characterisation and retention mechanisms at a full-scale municipal membrane bioreactor 总被引:3,自引:0,他引:3
Lyko S Al-Halbouni D Wintgens T Janot A Hollender J Dott W Melin T 《Water research》2007,41(17):3894-3902
In this study, for the first time a full-scale membrane bioreactor (MBR) was investigated with focus on organic compounds in activated sludge over a period of approximately 2 years. Soluble extracellular polymeric substances (EPS) in the sludge supernatant and permeate as well as bound EPS extracted from fouled membranes were determined photospectrometrically and revealed a typical composition of three main components in the order metals>humic acids>carbohydrates>proteins. Results showed an important influence on membrane fouling by soluble humic substances and carbohydrates in complexes with metal cations. It was found that Fe(2+) and Fe(3+) play a decisive role in natural organic matter (NOM) complexation and subsequent membrane blockage. The determination of molar mass distribution in supernatant and permeate by size exclusion chromatography (SEC) revealed a significant retention of macromolecular compounds by the porous membranes in the range of 10-50%. 相似文献
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The construction of a slide for examining living cells under the microscope under controlled conditions is described. 相似文献
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Thermophiles as Potential Source of Novel Endotoxin Antagonists: the Full Structure and Bioactivity of theLipo‐oligosaccharide from Thermomonas hydrothermalis 下载免费PDF全文
Dr. Flaviana Di Lorenzo Dr. Ida Paciello Dr. Luigi Lembo Fazio Dr. Luciana Albuquerque Dr. Luisa Sturiale Prof. Milton S. da Costa Prof. Rosa Lanzetta Prof. Michelangelo Parrilli Prof. Domenico Garozzo Prof. Maria Lina Bernardini Dott. Alba Silipo Prof. Antonio Molinaro 《Chembiochem : a European journal of chemical biology》2014,15(14):2146-2155
Thermomonas hydrothermalis is a Gram‐negative thermophilic bacterium that is able to live at 50 °C. This ability is attributed to chemical modifications, involving those to bacterial cell‐wall components, such as proteins and (glyco)lipids. As the main component of the outer membrane of Gram‐negative bacteria, lipopolysaccharides (LPSs) are exposed to the environment, thus they can undergo structural chemical changes to allow thermophilic bacteria to live at their optimal growth temperature. Furthermore, as one of the major target of the eukaryotic innate immune system, LPS elicits host immune response in a structure‐dependent mode; thus the uncommon chemical features of thermophilic bacterial LPSs might exert a different biological action on the innate immune system—an antagonistic effect, as shown in studies of LPS structure–activity relationship in the ongoing research into antagonist LPS candidates. Here, we report the complete structural and biological activity analysis of the lipo‐oligosaccharide isolated from Thermomonas hydrothermalis, achieved by a multidisciplinary approach (chemical analysis, NMR, MALDI MS and cellular immunology). We demonstrate a tricky and interesting structure combined with a very interesting effect on human innate immunity. 相似文献
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Antonio Albano Dott. Ing. Giorgio Ghelli Ph.D. Renzo Orsini Dott. 《The VLDB Journal The International Journal on Very Large Data Bases》1995,4(3):403-444
Fibonacci is an object-oriented database programming language characterized by static and strong typing, and by new mechanisms for modeling data-bases in terms of objects with roles, classes, and associations. A brief introduction to the language is provided to present those features, which are particularly suited to modeling complex databases. Examples of the use of Fibonacci are given with reference to the prototype implementation of the language. 相似文献
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Although assistive technology provides a promising means to accommodate for barriers to independence and self-determination for people with mental retardation, such devices are underutilized by this population. The Arc conducted a national survey of the use of assistive technology by people with mental retardation. In four of five areas, the percentage of individuals who used a device was under 10%. In two of these areas, the percentage of individuals who might benefit from a device exceeded the percentage who used a device, and in a third area, the percentage using devices was nearly equal to those who did not use but might benefit from a device. Availability and cost were reported as primary barriers. Suggestions were made to address these issues. 相似文献
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Kieny M.P.; Lathe R.; Rlvl?re Y.; Dott K.; Schmitt D.; Girard M.; Montagnler L.; Lecocq J.-P. 《Protein engineering, design & selection : PEDS》1988,2(4):317
Table I of this communication inadvertently contains an error.In the column headed Shedding of gp120 into the culturesupernatant, for recombinant 1136 ++ should read . 相似文献
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It was examined, whether methane can be used as hydrogen donor for an in situ denitrification of groundwater. It is demonstrated, that groundwater can serve as liquid medium and that the denitrification can occur at 10 degrees C. Efforts to enrich methanotrophic bacteria under anoxic conditions have not been successful. No methane oxidation occurred in the absence of oxygen. For this reason, the denitrification with methane must be performed in a two-stage process with aerobic methanotrophic bacteria producing metabolites, that are used as hydrogen donor by non-methanotrophic bacteria in anoxic areas. This kind of indirect denitrification was proved by quantifying nitrogen and nitrous oxide in enrichment cultures that were not stirred or shaken. Large numbers of non-methanotrophic bacteria being able to denitrify with methanol, acetate or proteins as sole hydrogen donor were enriched besides the methanotrophic bacteria under these conditions. 相似文献
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Large amounts of lubricants having strong environmental effects are released into the environment. This has led to the development of so‐called ‘environmentally acceptable’ lubricants based on synthetic and/or native esters. The aquatic toxicity of these lubricants is low and they are readily biodegradable. However, the biodegradation rate can be reduced after application. The aim of this study is to understand the lower biodegradation rate and the processes occurring during application. The changes are quantified using elemental analyses, high performance liquid chromatography with evaporative light scattering detector and mass spectrometer, as well as a combined screening method consisting of Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy and electrospray ionization mass spectrometry. The results of chemical analyses indicate that the main components are cracked, and double bonds of the main components are eliminated by oxidation causing polymerization effects. The intensity of these effects is dependent on the kind of use and the presence of additives. These modifications are responsible for the changes in the ecological and technical characteristics. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献