Disposal of heavy metal bearing hazardous waste using chemical fixation and solidification

The Chemical Fixation and Solidification (CFS) process has been successfully applied to flyash from a glass-manufacturer and to arsenic trioxide wastes from roasting auriferous pyrite concentrates. Both wastetypes have been solidified with or without chemical fixation by addition of various amounts of Portland Cement. Leachability and unconfined compressive strength of the produced solidified waste were used as parameters to assess the efficacy of the CFS process. Leachability data for the solidified wastes was obtained by conducting standard leaching tests such as the Toxicity Characteristic Leaching Procedure (TCLP) and the Dynamic Leach Test (DLT). For the arsenic trioxide waste the leachability data was used to model long term leachability. This paper outlines the results from the application of the CFS process to industrial flyash and of arsenic trioxide waste and discuss the long term leaching models developed to predict leaching from arsenic trioxide waste

Rhythmic Diurnal Gene Expression in Human Adipose Tissue From Individuals Who Are Lean, Overweight, and Type 2 Diabetic

OBJECTIVE Previous animal studies suggest a functional relationship between metabolism, type 2 diabetes, and the amplitude of daily rhythms in white adipose tissue (WAT). However, data interpretation is confounded by differences in genetic background and diet or limited sampling points. We have taken the novel approach of analyzing serial human WAT biopsies across a 24-h cycle in controlled laboratory conditions.RESEARCH DESIGN AND METHODS Lean (n = 8), overweight/obese (n = 11), or overweight/obese type 2 diabetic (n = 8) volunteers followed a strict sleep-wake and dietary regimen for 1 week prior to the laboratory study. They were then maintained in controlled light-dark conditions in a semirecumbent posture and fed hourly during wake periods. Subcutaneous WAT biopsies were collected every 6 h over 24 h, and gene expression was measured by quantitative PCR.RESULTS Lean individuals exhibited significant (P 0.05) of increased body weight or type 2 diabetes on rhythmic gene expression.CONCLUSIONS The robust nature of these rhythms and their relative phasing indicate that WAT now can be considered as a peripheral tissue suitable for the study of in vivo human rhythms. Comparison of data between subject groups clearly indicates that obesity and type 2 diabetes are not related to the amplitude of rhythmic WAT gene expression in humans maintained under controlled conditions. Diabetes 60:1577-1581, 201

Sludge Management for the 21st Century Selected Proceedings of the International Specialist Conference on Sludge Management for the 21st Century, held in Freemantle, Western Australia, 8-10 April 1999

With improvements in wastewater treatment has come an increase in the production of sewage sludge. In addition the materials disposed into the sewerage system by modern society mean that sludge is not only rich in organic carbon and pathogens, but also in heavy metals and other pollutants. The IWA Specialist Group in Sludge Management recognised these challenges, and is addressing them in a series of specialist conferences: the one in April 1999 in Perth, Australia focused on thermal processes and their management. With over a hundred participants from more than 30 countries the conference proved highly successful. These proceedings contain papers which were selected from the original 37 presentations after passing through the review process. Papers covered the whole range of thermal processes: hydrothermal oxidation, gasification, pyrolysis, incineration, melting to reuse of process residues. Management issues and assessment of sustainability of thermal processes based on life-cycle analyses were debated, with a focus on "value-adding" sludge management systems and renewable resource options

Rhythmic gene expression in human adipose tissue from individuals who are lean, overweight and have type 2 diabetes

OBJECTIVE Previous animal studies suggest a functional relationship between metabolism, type 2 diabetes, and the amplitude of daily rhythms in white adipose tissue (WAT). However, data interpretation is confounded by differences in genetic background and diet or limited sampling points. We have taken the novel approach of analyzing serial human WAT biopsies across a 24-h cycle in controlled laboratory conditions.RESEARCH DESIGN AND METHODS Lean (n = 8), overweight/obese (n = 11), or overweight/obese type 2 diabetic (n = 8) volunteers followed a strict sleep-wake and dietary regimen for 1 week prior to the laboratory study. They were then maintained in controlled light-dark conditions in a semirecumbent posture and fed hourly during wake periods. Subcutaneous WAT biopsies were collected every 6 h over 24 h, and gene expression was measured by quantitative PCR.RESULTS Lean individuals exhibited significant (P 0.05) of increased body weight or type 2 diabetes on rhythmic gene expression.CONCLUSIONS The robust nature of these rhythms and their relative phasing indicate that WAT now can be considered as a peripheral tissue suitable for the study of in vivo human rhythms. Comparison of data between subject groups clearly indicates that obesity and type 2 diabetes are not related to the amplitude of rhythmic WAT gene expression in humans maintained under controlled conditions. Diabetes 60:1577-1581, 201

Experimental support for the “E pathway hypothesis” of coupled transmembrane e(–) and H(+) transfer in dihemic quinol:fumarate reductase

Reconciliation of apparently contradictory experimental results obtained on the quinol:fumarate reductase, a diheme-containing respiratory membrane protein complex from Wolinella succinogenes, was previously obtained by the proposal of the so-called “E pathway hypothesis.” According to this hypothesis, transmembrane electron transfer via the heme groups is strictly coupled to cotransfer of protons via a transiently established pathway thought to contain the side chain of residue Glu-C180 as the most prominent component. Here we demonstrate that, after replacement of Glu-C180 with Gln or Ile by site-directed mutagenesis, the resulting mutants are unable to grow on fumarate, and the membrane-bound variant enzymes lack quinol oxidation activity. Upon solubilization, however, the purified enzymes display ≈1/10 of the specific quinol oxidation activity of the wild-type enzyme and unchanged quinol Michaelis constants, K(m). The refined x-ray crystal structures at 2.19 Å and 2.76 Å resolution, respectively, rule out major structural changes to account for these experimental observations. Changes in the oxidation–reduction heme midpoint potential allow the conclusion that deprotonation of Glu-C180 in the wild-type enzyme facilitates the reoxidation of the reduced high-potential heme. Comparison of solvent isotope effects indicates that a rate-limiting proton transfer step in the wild-type enzyme is lost in the Glu-C180 → Gln variant. The results provide experimental evidence for the validity of the E pathway hypothesis and for a crucial functional role of Glu-C180