Interactive effects of the electron acceptor sulphate and o-cresol on the methanogenic degradation of hexanoate

A three-stage continuous culture system was used to segregate the component microbial groups of a methanogenic hexanoate-degrading association enriched from anaerobic refuse. The inhibitory effects of o-cresol concentrations (2-20 mM) on the fermentative, acetogenic, sulphate-reducing and methanogenic bacteria were then assessed in the presence of either 1.4 or 3.5 mM sulphate in the influent medium. The sulphate-reducing bacteria (SRB) in the 1.4 mM sulphate-supplemented systems were the most sensitive to o-cresol, with 29.3 and 56.6% inhibition on supplementation with 4 and 6 mM o-cresol, respectively. With 3.5mM supplementation, inhibition was 4.5 and 19.4%, respectively. Methanogenesis was not inhibited by concentrations < 10 mM o-cresol, and complete inhibition was recorded only at concentrations > or = 10 mM. Both fermentation and acetogenesis were affected by inhibition of the electron sinks. The increase in influent sulphate concentration promoted electron flow to sulphidogenesis, as predicted on thermodynamic criteria, but did not affect the relative sensitivity of the different physiological groups.     

Vaginal colonization with Group B beta-hemolytic streptococcus as a risk factor for post-cesarean section febrile morbidity

Vaginal colonization of mothers with Group B beta-hemolytic streptococcus (GBS) has been recognized as a risk factor for neonatal morbidity. The relationship of GBS colonization to risks for the mother who undergoes cesarean section has not been defined. In this study, we found that, among patients who underwent cesarean section, the 19% of them who were colonized with GBS had a higher incidence of standard fever (66.6% vs. 30.5%), clinical diagnosis of endomyometritis (61.1% vs. 12.5%), and use of antibiotics (61.1% vs. 26.3%) in relationship to a significantly increased frequency of premature rupture of the membranes (50.0% vs. 14.8%). Reasons for the association between vaginal colonization and increased morbidity are discussed.     

Identification of potent human anti-IL-1RI antagonist antibodies

Interleukin-1 (IL-1) blockade by IL-1 receptor antagonist benefits some arthritis patients by reducing joint damage. This fact inspired us to develop antagonist human therapeutic antibodies against IL-1R(I) using phage libraries that display single-chain variable fragment (scFv) antibody fragments. Panning libraries against human IL-1R(I) generated 39 unique scFv-phage whose binding to IL-1R(I) was competed by IL-1 ligands. Fifteen of these scFv-phage, identified using IL-1R(I)-binding assays and dissociation rate ranking, were reformatted as scFv-Fc and IgG(4) molecules. The ease of producing antibodies in the scFv-Fc format permitted rapid identification of four lead clones (C10, C13, C14, C15) that inhibit NF-kappaB nuclear translocation induced by IL-1. Reformatting these clones as IgG(4) molecules increased their inhibition potency by 相似文献   

Fatty acid profile of traditional soymilk

Soymilk is a water extract of soybeans, closely resembling dairy milk in physical appearance and composition. Most fatty acids in soybean and its derivates are unsaturated, and therefore susceptible to oxidation. The aim of this study was to evaluate the possible effect of the thermal conditions during the elaboration process of soymilk on its fatty acid profile. For this, the fatty acid composition of soymilk, okara (soymilk residue), and soybean were studied by gas chromatography with flame ionization detection (GC-FID). No major differences in the fatty acid patterns were found.     

PBDEs, PBBs, and PCNs in three communities of free-ranging killer whales (Orcinus orca) from the northeastern Pacific Ocean

Polybrominated diphenyl ethers (PBDEs), polybrominated biphenyls (PBBs), and polychlorinated naphthalenes (PCNs) were quantified in blubber biopsy samples collected from free-ranging male and female killer whales (Orcinus orca) belonging to three distinct communities (southern residents, northern residents, and transients) from the northeastern Pacific Ocean. High concentrations of sigmaPBDE were observed in male southern residents (942+/-582 ng/g Iw), male and female transients (1015+/-605 and 885+/-706 ng/g Iw, respectively), and male and female northern residents (203+/-116 and 415+/-676 ng/g Iw, respectively). Because of large variation within sample groups, sigmaPBDE levels generally did not differ statistically with the exception of male northern residents, which had lower sigmaPBDE concentrations than male southern residents, male transients, and female transients, perhaps reflecting the consumption of less contaminated prey items. Male transient killer whales, which consume high trophic level prey including other cetaceans and occasionally spend time near populated areas, had sigmaPBDE concentrations approximately equal to southern residents. No significant age-related relationships were observed for sigmaPBDE concentrations. sigmaPBDE concentrations were approximately 1-3 orders of magnitude greater than those of sigmaPBB (3.0-31 ng/g Iw) and sigmaPCN (20-167 ng/g Iw) measured in a subset of samples, suggesting that PBDEs may represent a contaminant class of concern in these marine mammals.     

Formation of haloacetic acids during monochloramination

Factors that affect the formation of haloacetic acids (HAAs) during monochloramination, such as monochloramine application techniques, the initial chlorine (Cl) to ammonia-N (N) ratios, the bromide concentrations, and the wastewater quality, were studied. Aqueous humic acid solutions and undisinfected wastewater effluent samples obtained from two Hong Kong Sewage Treatment Works (STWs) were monochloraminated under various conditions. HAA formation was strongly affected by the monochloramine application techniques. The formation of trichloroacetic acid (TCAA) and total HAAs was reduced by adding preformed monochloramine. A higher initial Cl:N ratio indicated a higher chlorine demand and consequently led to higher HAA yields. Increasing the bromide concentration shifted HAAs from chlorinated species to brominated species and increased the yields of total HAAs, concurrent with decreases in the yields of dichloroacetic acid (DCAA) and TCAA but with increases in those of the other HAAs measured. Variations in the patterns of HAA formation were observed in monochloraminated wastewater effluent samples. The variations cannot be simply explained by the chlorine chemistry involving ammonia and/or bromide but are likely attributable to the combining effects of the water quality and the characteristics of the organics in the wastewater.     

An editing tool that manages device associations in an in-home environment

The forthcoming home environment will comprise numerous computationally enhanced artifacts that are autonomous, but interconnected via an invisible web of network-based services. The approach presented in this paper is to enable end users to make their own applications by linking such artifacts, which are treated as reusable components. A key requirement to achieve this is the availability of editing tools that meet the needs of different classes of users. A tool of this kind designed for end users is presented in this paper, together with the outcome of user evaluation sessions.     

Environmental exposure assessment of fluoroquinolone antibacterial agents from sewage to soil

The behavior of fluoroquinolone antibacterial agents (FQs) during mechanical-biological wastewater treatment was studied by mass flow analysis. In addition, the fate of FQs in agricultural soils after sludge application was investigated. Concentrations of FQs in filtered wastewater (raw sewage, primary, secondary, and tertiary effluents) were determined using solid-phase extraction with mixed phase cation exchange disk cartridges and reversed-phase liquid chromatography with fluorescence detection. FQs in suspended solids, sewage sludge (raw, excess, and anaerobically digested sludge), and sludge-treated soils were determined as described for the aqueous samples but preceded by accelerated solvent extraction. Wastewater treatment resulted in a reduction of the FQ mass flow of 88-92%, mainly due to sorption on sewage sludge. A sludge-wastewater partition coefficient (log Kd approximately 4) was calculated in the activated sludge reactors with a hydraulic residence time of about 8 h. No significant removal of FQs occurred under methanogenic conditions of the sludge digesters. These results suggest sewage sludge as the main reservoir of FQ residues and outline the importance of sludge management strategies to determine whether most of the human-excreted FQs enter the environment. Field experiments of sludge-application to agricultural land confirmed the long-term persistence of trace amounts of FQs in sludge-treated soils and indicated a limited mobility of FQs into the subsoil.     

Rapidly increasing polybrominated diphenyl ether concentrations in the Columbia River system from 1992 to 2000

Concentrations and congener patterns of 32 individual PBDE congeners from mono- through hexa-brominated were investigated in two fish species occupying similar habitats--but having different diets and trophic levels--and surficial sediments from several locations on the major river system of western North America, the Columbia River, in southeastern British Columbia, Canada. Total PBDE concentrations have increased by up to 12-fold over the period from 1992 to 2000 in mountain whitefish from the Columbia River, with a doubling period of 1.6 years. The rate at which PBDE concentrations are increasing in whitefish is greater than has been previously reported worldwide. At the current rate of increase, sigmaPBDE will surpass those of sigmaPCB by 2003 to become the most prevalent organo-halogen contaminant in this region. SigmaPBDE in whitefish from the mainstem of the Columbia River range up to 72 ng/g wet weight, concentrations that are 20-50-fold higher than in a nearby pristine watershed affected only by atmospheric contaminant transport. Conversely, sigmaPBDE in largescale suckers were approximately an order of magnitude lower than in whitefish, demonstrating the influence of biomagnification and feeding habits. Congener patterns in whitefish from the Columbia River directly correlated with the two major commercial penta-BDE mixtures in use and represent the first time free-swimming aquatic biota such as fish have been found to contain PBDE congener patterns so similar to commercial mixtures. PBDE concentrations in sediments were not linked to a variety of investigated point sources but were instead inversely correlated with the ratio of organic carbon:organic nitrogen in surficial sediments with a pattern suggesting the dominant influence of septic field inputs from the primarily rural population.