Influence of liquid- and solid-state coupling anaerobic digestion process on methane production of cow manure and rice straw

Journal of Material Cycles and Waste Management - Based on the different characteristics of cow manure and rice straw, liquid- and solid-state coupling anaerobic digestion (L-SS-AD) is designed in...     

Rheology of Lyocell Solutions from Different Cellulose Sources

Rheological measurements were used to characterize the behavior of lyocell solutions, i.e., cellulose dissolved in N-methymorpholine-N-oxide. Cellulose sources included dissolving pulp, kraft pulp, sugar cane fibers, and kenaf fibers. The dominance of viscous behavior, G values, over elastic behavior, G values, is affected by cellulose concentration and molecular weight. At lower concentrations and degrees of polymerization (DP), dissolving pulp solutions show viscous, inelastic behavior at low frequencies. At higher concentration and DP, dissolving pulp solutions are more elastic at higher frequencies. Solutions prepared with kenaf and sugar cane fibers show similar properties to those using pure dissolving pulp, and comparisons suggest the molecular weight and/or the presence of other substances such as lignin in the cellulose from these alternative sources affect the rheology.     

Trace elements in biodeposits and sediments from mussel culture in the Ria de Arousa (Galicia, NW Spain)

The trace elements present at highest concentrations were Cr and Zn, which probably originated from the dumping of effluent from a tanning factory. High proportions of these two elements were associated with the residual fraction. Biodeposits and sediments showed high concentrations of Cd and Pb in the reactive fraction, with a high proportion of the concentration in the reactive fraction being associated with carbonates. Nickel showed a higher degree of pyritization than the previous elements, although most of the Ni was associated with the residual and reactive fractions. Arsenic, Hg and Cu showed high degrees of pyritization, particularly below a depth of 5 cm. The results demonstrate that those elements with a high degree of pyritization may be released into the water through oxidation of the metal sulphides that they form when in suspension in oxic sea water, with the subsequent risk of increased bioavailability to benthic fauna.     

Selecting peptide ligands of microcystin-LR from phage displayed random libraries

In the present study, we investigated to find novel ligands for low molecular weight environmental toxin, microcystin-LR (MC-LR) by using phage display technology. Two random libraries, displaying linear 12-mer peptides and cyclic 7-mer peptides, were screened against the immobilized target respectively. After three rounds of panning, phage clones that recognized microcystin-LR specifically were obtained from both the linear and the constrained libraries, proved by enzyme-linked immumosorbent assays and immunoprecipitation assays. DNA sequencing indicated that peptides displayed on some of the selected clones shared consensus sequences. Compared with traditional methods, this approach provided a cheaper and more rapid alternative to screen specific ligands for microcystin-LR. Moreover, since it is rather difficult to take small molecules as targets of phage display libraries, the success of this experiment expanded the applications of phage display technology, and provided a new avenue to study environmental small molecular toxins.     

Automated radioxenon monitoring for the comprehensive nuclear-test-ban treaty in two distinctive locations: Ottawa and Tahiti

In preparation for verification of the Comprehensive Nuclear-Test-Ban-Treaty, automated radioxenon monitoring is performed in two distinctive environments: Ottawa and Tahiti. These sites are monitored with SPALAX (Systeme de Prelevement d'air Automatique en Ligne avec l'Analyse des radioXenons) technology, which automatically extracts radioxenon from the atmosphere and measures the activity concentrations of (131m,133m,133,135)Xe. The resulting isotopic concentrations can be useful to discern nuclear explosions from nuclear industry xenon emissions. Ambient radon background, which may adversely impact analyser sensitivity, is discussed. Upper concentration limits are reported for the apparently radioxenon free Tahiti environment. Ottawa has a complex radioxenon background due to proximity to nuclear reactors and medical isotope facilities. Meteorological models suggest that, depending on the wind direction, the radioxenon detected in Ottawa can be characteristic of the normal radioxenon background in the Eastern United States, Europe, and Japan or distinctive due to medical isotope production.     

Mercury in surface waters of a macrotidal urban estuary (River Adour, south-west France)

Surface waters were collected in the River Adour estuary (south-western France) during different sampling periods from 1998 to 2001 in order to investigate the phase distribution and speciation of methylmercury (MeHg⁺). Although a high variability is observed, significant higher average concentrations of total MeHg⁺ (dissolved and particulate) are measured during the warm seasons, at 4.40±8.18 pM and 3.90±1.87 pM for July 1998 and September 1999, compared with the winter seasons, with concentrations at 0.99±2.85 pM and 1.00±1.75 pM for February 1998 and February 2001, respectively (one-tailed t-test, P=0.01). The seasonal variations are explained with enhanced bacterial activity during summer and sedimentation/resuspension phenomena. Additionally, signi-ficant longitudinal variations of the MeHg⁺ concentrations are observed. The highest levels in both dissolved and particulate fractions are found within the downstream urban estuarine area. This can be explained by the high methylation potential of the sediments, but direct anthropogenic inputs of MeHg⁺ from specific discharge points cannot be neglected. Biogeochemical factors like phytoplankton biomass and salinity also show a relationship with MeHg⁺ partitioning in the surface waters of the Adour estuary.     

江苏、南部下、中侏罗统的划分

江苏南部的下、中侏罗统,长期以来笼统称之为象山群。本文根据地层岩性特征和大量动植物化石的研究,结合与邻区地层之对比,将江苏南部下、中侏罗统进一步划分为下侏罗统南象山组及中侏罗统北象山组;前者为含煤地层,大致相当于原象山群下部(或下段为),后者为红色地层,大致相当于原象山群上部(或上段)。     

Effects of aluminum on physiological metabolism and antioxidant system of wheat (Triticum aestivum L.)

We have found that rice bran effectively adsorbed chloroform from tap water. The amount of chloroform adsorbed was plotted against the equilibrium concentration of chloroform in solution on a logarithmic scale. A linear relationship was obtained, indicating that the adsorption reaction was a Freundlich type. The removal of chloroform by rice bran was attributed to the uptake into intracellular particles called spherosomes.     

Assessment of current exposure levels in different population groups of the Kola Peninsula

Activity concentrations of 137Cs and 90Sr in samples of vegetation and natural food products collected in the Kola Peninsula in 1998 and 1999 indicate a very slow decrease in contamination levels during the last decade, mainly due to the physical decay of the radionuclides. The activity concentrations of 137Cs in reindeer meat decreased with a half-life of about 9 years. 137Cs in lichen, moss and fungi is significantly higher than in natural vegetation (grasses) and agricultural plants (potatoes). The activity concentrations of 137Cs in reindeer meat were two orders of magnitude higher than those in locally produced beef and pork. Consumption of reindeer meat, fish, mushrooms and berries constituted the main contribution to the internal dose from 137Cs and 90Sr for reindeer-breeders in the Lovozero area. The estimated committed doses due to 137Cs intake in this group were about 10 microSv per month in summer 1998 and 15 microSv per month in winter, 1999. There was good agreement between internal dose estimates based on intake assessment and whole body measurements. The population of Umba settlement, which is not involved in reindeer breeding, received individual committed doses due to 137Cs intake of about 0.5 microSv per month, about a factor of 20 less than the reindeer-breeders in Lovozero. In this case, the main contribution to the internal dose of the general population came from consumption the of 137Cs in mushrooms and forest berries. The contribution of 90Sr to the internal dose varied from 1% to 5% in the different population groups studied.