Showing papers on "Water environment published in 2002"

Mine Water: Hydrology, Pollution, Remediation

Abstract: Foreword R.F. Rubio. Preface. 1. Mining and the Water Environment. 2. Mine Water Chemistry. 3. Mine Water Hydrology. 4. Active Treatment of Polluted Mine Waters. 5. Passive Treatment of Polluted Mine Waters. Appendix. References. Index.

Microbial Agents Associated with Waterborne Diseases

Abstract: Many classes of pathogens excreted in feces are able to initiate waterborne infections. There are bacterial pathogens, including enteric and aquatic bacteria, enteric viruses, and enteric protozoa, which are strongly resistant in the water environment and to most disinfectants. The infection dose of viral and protozoan agents is lower than bacteria, in the range of one to ten infectious units or oocysts. Waterborne outbreaks of bacterial origin (particularly typhoid fever) in the developing countries have declined dramatically from 1900s. Therefore, some early bacterial agents such as Shigella sonnei remains prevalent and new pathogens of fecal origin such as zoonotic C. jejuni and E. coli O157:H7 may contaminate pristine waters through wildlife or domestic animal feces. The common feature of these bacteria is the low inoculum (a few hundred cells) that may trigger disease. The emergence in early 1992 of serotype O139 of V. cholerae with epidemic potential in Southeast Asia suggests that other serotypes than V. cholerae O1 could also getting on epidemic. Some new pathogens include environmental bacteria that are capable of surviving and proliferating in water distribution systems. Other than specific hosts at risk, the general population is refractory to infection with ingested P. aeruginosa. The significance of Aeromonas spp. in drinking water to the occurrence of acute gastroenteritis remains a debatable point and has to be evaluated in further epidemiological studies. Legionella and Mycobacterium avium complex (MAC) are environmental pathogens that have found an ecologic niche in drinking and hot water supplies. Numerous studies have reported Legionnaires' disease caused by L. pneumophila occurring in residential and hospital water supplies. M. avium complex frequently causes disseminated infections in AIDS patients and drinking water has been suggested as a source of infection; in some cases the relationship has been proven. More and more numerous reports show that Helicobacter pylori DNA can be amplified from feces samples of infected patients, which strongly suggests fecal-to-oral transmission. Therefore, it is possible that H. pylori infection is waterbome, but these assumptions need to be substantiated. Giardiasis has become the most common cause of human waterborne disease in the U.S. over the last 30 years. However, as a result of the massive outbreak of waterborne cryptosporidiosis in Milwaukee, Wisconsin, affecting an estimated 403,000 persons, there is increasing interest in the epidemiology and prevention of new infection disease caused by Cryptosporidium spp. as well as monitoring water quality. The transmission of Cryptosporidium and Giardia through treated water supplies that meet water quality standards demonstrates that water treatment technologies have become inadequate, and that a negative coliform no longer guarantees that water is free from all pathogens, especially from protozoan agents. Substantial concern persists that low levels of pathogen occurrence may be responsible for the endemic transmission of enteric disease. In addition to Giardia and Cryptosporidium, some species of genera Cyclospora, Isospora, and of family Microsporidia are emerging as opportunistic pathogens and may have waterborne routes of transmission. More than 15 different groups of viruses, encompassing more than 140 distinct types can be found in the human gut. Some cause illness unrelated with the gut epithelium, such as Hepatitis A virus (HAV) and Hepatitis E virus (HEV). Numerous large outbreaks have been documented in the U.S. between 1950 and 1970, and the incidence rate has strongly declined in developing countries since the 1970s. Hepatitis E is mostly confined to tropical and subtropical areas, but recent reports indicate that it can occur at a low level in Europe. A relatively small group of viruses have been incriminated as causes of acute gastroenteritis in humans and fewer have proven to be true etiologic agents, including rotavirus, calicivirus, astrovirus, and some enteric adenovirus. These enteric viruses have infrequently been identified as the etiologic agents of waterborne disease outbreaks, because of inadequate diagnostic technology, but many outbreaks of unknown etiology currently reported are likely due to viral agents. Actually, Norwalk virus and Norwalk-like viruses are recognized as the major causes of waterborne illnesses world-wide. The global burden of infectious waterborne disease is considerable. Reported numbers highly underestimate the real incidence of waterborne diseases. The most striking concern is that enteric viruses such as caliciviruses and some protozoan agents, such as Cryptosporidium, are the best candidates to reach the highest levels of endemic transmission, because they are ubiquitous in water intended for drinking, being highly resistant to relevant environmental factors, including chemical disinfecting procedures. Other concluding concerns are the enhanced risks for the classic group of debilitated subjects (very young, old, pregnant, and immunocompromised individuals) and the basic requirement of to take specific measures aimed at reducing the risk of waterborne infection diseases in this growing, weaker population.

Biological water at the protein surface: dynamical solvation probed directly with femtosecond resolution.

Abstract: Biological water at the interface of proteins is critical to their equilibrium structures and enzyme function and to phenomena such as molecular recognition and protein-protein interactions. To actually probe the dynamics of water structure at the surface, we must examine the protein itself, without disrupting the native structure, and the ultrafast elementary processes of hydration. Here we report direct study, with femtosecond resolution, of the dynamics of hydration at the surface of the enzyme protein Subtilisin Carlsberg, whose single Trp residue (Trp-113) was used as an intrinsic biological fluorescent probe. For the protein, we observed two well separated dynamical solvation times, 0.8 ps and 38 ps, whereas in bulk water, we obtained 180 fs and 1.1 ps. We also studied a covalently bonded probe at a separation of approx 7 A and observed the near disappearance of the 38-ps component, with solvation being practically complete in (time constant) 1.5 ps. The degree of rigidity of the probe (anisotropy decay) and of the water environment (protein vs. micelle) was also studied. These results show that hydration at the surface is a dynamical process with two general types of trajectories, those that result from weak interactions with the selected surface site, giving rise to bulk-type solvation (approx 1 ps), and those that have a stronger interaction, enough to define a rigid water structure, with a solvation time of 38 ps, much slower than that of the bulk. At a distance of approx 7 A from the surface, essentially all trajectories are bulk-type. The theoretical framework for these observations is discussed.

High-resolution solid-state CPMAS NMR study of archaeological woods.

Abstract: High-resolution nuclear magnetic resonance of carbon-13 was employed to characterize archaeological wood samples from the 11th century excavation site in the lake Paladru at Charavines, France. Structural and chemical modifications were assessed by comparing the structural features of archaeological wood of beech with modern wood. The main results concern the strong decrease of a sugar moiety with a complete disappearance of hemicelluloses. During aging in a water environment, the β-O-4 interunit linkages of lignins have not been degraded. The analysis of the NMR spectra reveals that the residues occurring during depletion of sugars were not recombined inside the lignocellulosic matrix. Finally, in this article we illustrate the possibility of analyzing small amounts (4−6 mg) of starting material within reasonable experimental time using modern equipment.

Rivers as living systems

Abstract: 1. Fresh water and the ecosystem functions of catchments are essential to all life, and provide benefits upon which society depends. Yet there is widespread evidence of increasing degradation of river quality in many parts of the world. 2. Rivers are complex living systems, and must be managed on a systemic basis. Historic parochial approaches to management can exacerbate wider-scale problems by degrading ecosystem functions. 3. Reversal of long-term ecosystem degradation, not merely reducing the rate of ongoing damage to ecosystem functioning, is vital for achieving sustainability. In an already ecologically impoverished world, restoring ecosystem functions and the capacity of catchments to support human needs may be the only form of investment in a sustainable longer-term future. 4. A ‘building block’ approach can enable local issues to be addressed by technologies that protect or restore ecosystem functions at the catchment scale. They may also represent a cost-effective means for targeting investment. 5. Shifts in thinking and action are required if a move from a reactive to a systemic approach to the water environment is to be achieved. These shifts include acknowledgement of the central importance of ecosystem functions, protecting these functions through management action, valuing them appropriately, and taking longer-term and wider-scale perspectives in management decisions. A focus on restoration of function at the catchment scale, achieved through greater inclusion of all sectors of society in decision-making, is an essential element of this approach. Copyright © 2002 John Wiley & Sons, Ltd.

Subpicosecond spectroscopy of liquid water in the infrared: Effect of deuteration on the structural and vibrational dynamics

Abstract: The spectral substructure and the dynamics of the OH- and OD-stretching bands of HDO in the diluted isotopic mixtures with D2O and for the first time H2O are investigated using 2-color IR spectroscopy with tunable subpicosecond pulses. From the observed transient band shapes, we derive four major spectral components within the OH-band of HDO in the solvent D2O peaked at approximately 3330 cm-1 (I), 3390 cm-1(II), 3460 cm-1 (III), and 3520 cm-1 (IV), as well as three corresponding species in the case of the OD-band in the solvent H2O. The components display no distinct temperature dependence of position and spectral width in the investigated temperature range 273−343 K. Comparing the OH-stretching mode of HDO:D2O to the OD-vibration of HDO:H2O, the population lifetime increases significantly from 1.0 ps for OH to 1.8 ps (±0.2 ps) for OD at room temperature, whereas spectral relaxation, assigned to structural changes, seems to slow from 1.0 ± 0.4 ps to 2.0 ± 0.8 ps in the protonated water environment.

The Underwater Life of Secondarily Aquatic Plants: Some Problems and Solutions

Abstract: The freshwater secondarily aquatic plants, most of which are higher plants, are those returned to the water environment after spending a period of time living on land. The readaptation to living underwater has made it necessary for these plants to put in place morphological and functional strategies to cope with some major problems due to features of the aquatic environment, but also deriving from the specialized organization of their “terrestrial” bodies. The poor O2 availability underwater accounted for the evolution of wide aerenchyma tissues throughout the plant organs to improve the photosynthetic O2 flux from the shoot to the roots buried in anoxic sediments and to the neighboring rhizosphere. This favors sediment oxygenation, sustains the aerobic metabolism of roots, and improves the availability and uptake of mineral nutrients, whose delivery to the entire plants, without a transpirational flux, is ensured by an acropetal mass transport depending on root pressure, guttation from hydathodes and cha...

Interdecadal change in the upper water column environment and spring diatom community structure in the Japan Sea: an early summer hypothesis

Abstract: Diatom community structure in the offshore Tsushima Current area of the Japan Sea was studied from 1972 to 1999 in relation to temporal variability of the upper water environment. We observed a distinct change in the community structure in spring during the 1980s, the period after the 1976/77 climate regime shift which has been reported to occur in the vast areas of the North Pacific. Chlorophyll a (chl a) concentration and chl a per cell were markedly low, and summer species includ- ing Pseudonitzschia spp. dominated the diatom community in spring during the 1980s. Mixed layer phosphate concentrations during the 1980s were lower in spring compared to the1970s and 1990s, suggesting that nutrient depletion to levels limiting diatom growth might occur early. This change seemed subsequently to cause a shift in the dominant diatom species from those adapted to eutrophic conditions to those adapted to oligotrophic conditions. Density profiles between the surface and 300 m showed the thickness of the surface Tsushima Current water and the cold subsurface water decreasing and increasing, respectively, from the late 1970s to the late 1980s. In addition, spring solar radiation increased during the 1980s. These conditions indicate intensified stratification of the upper water column. Increases in the phosphate gradient between the surface and subsurface layers sug- gested that the intensified stratification reduced nutrient supply to the surface and may be responsi- ble for early formation of the summer-like oligotrophic conditions. Based on these results, we propose the 'early summer hypothesis' as the cause of the apparent decline of the spring phytoplankton bio- mass in the Japan Sea during the 1980s.

Some Aspects of Speciation of Mercury in a Water Environment

Abstract: Extreme toxicity of some species of mercury, the ability of this element to bioaccumulate in particular in fish meat, and the known cases of lethal poisoning by mercury have drawn particular attention to this element's presence in the natural environment. Due to the relatively long time of its presence in the air, elemental mercury can be transported over large distances, hence the presence of mercury of anthropogenic origin is detected practically all over the world. Apart from the elemental mercury, the main species of mercury in water are Hg(II) and mercury-organic species, in particular methylmercury. The latter undergoes strong bioaccumulation in living organisms and concentration in the trophic chains. That is why the relative concentration of mercury in organisms is determined by its presence in water. The concentration of mercury in water is related to the processes of methylation and demethylation, influenced by biotic and abiotic factors such as the activity of microogranisms, access to oxygen, illumination, temperature, pH and others. Despite intense studies, full and reliable recognition of the ecological and health effects of pollution by this toxic metal is still impossible. The aim of this paper is to present the problems related to speciation of mercury, and describe some conversion and migration processes of mercury in the water environment.

Key issues in the computational simulation of GPCR function: representation of loop domains.

Abstract: Some key concerns raised by molecular modeling and computational simulation of functional mechanisms for membrane proteins are discussed and illustrated for members of the family of G protein coupled receptors (GPCRs). Of particular importance are issues related to the modeling and computational treatment of loop regions. These are demonstrated here with results from different levels of computational simulations applied to the structures of rhodopsin and a model of the 5-HT2A serotonin receptor, 5-HT2AR. First, comparative Molecular Dynamics (MD) simulations are reported for rhodopsin in vacuum and embedded in an explicit representation of the membrane and water environment. It is shown that in spite of a partial accounting of solvent screening effects by neutralization of charged side chains, vacuum MD simulations can lead to severe distortions of the loop structures. The primary source of the distortion appears to be formation of artifactual H-bonds, as has been repeatedly observed in vacuum simulations. To address such shortcomings, a recently proposed approach that has been developed for calculating the structure of segments that connect elements of secondary structure with known coordinates, is applied to 5-HT2AR to obtain an initial representation of the loops connecting the transmembrane (TM) helices. The approach consists of a simulated annealing combined with biased scaled collective variables Monte Carlo technique, and is applied to loops connecting the TM segments on both the extra-cellular and the cytoplasmic sides of the receptor. Although this initial calculation treats the loops as independent structural entities, the final structure exhibits a number of interloop interactions that may have functional significance. Finally, it is shown here that in the case where a given loop from two different GPCRs (here rhodopsin and 5-HT2AR) has approximately the same length and some degree of sequence identity, the fold adopted by the loops can be similar. Thus, in such special cases homology modeling might be used to obtain initial structures of these loops. Notably, however, all other loops in these two receptors appear to be very different in sequence and structure, so that their conformations can be found reliably only by ab initio, energy based methods and not by homology modeling.

Characterizing and Modeling the Hydrolysis of Polyamide-11 in a pH 7 Water Environment

Abstract: Multiangle laser light scattering (MALLS) is used to monitor changes in molecular weight during solid state aging of polyamide-11 (PA-11). A mathematical model is presented which successfully describes the degradation kinetics of PA-11 in pH 7 water. The MALLS results demonstrate that there is a recombination reaction in the solid state, which may be described as a cage effect during hydrolysis−degradation of the amide bond. During aging, the competing recombination and hydrolysis reactions lead to the formation of an equilibrium molecular weight. The equilibrium molecular weight is surprisingly high at about 26 000 in pH 7 water, a value close to the ductile−brittle transition. The activation energy of hydrolysis is 81 to 87 kJ/mol, close to the values of previous acid degradation studies and a recent value of 96 kJ/mol for hydrolysis of the peptide amide bond.

Environmental effects induced by human activities in arid Shiyang River basin, Gansu province, northwest China

Abstract: Shiyang River basin is located in Hexi Corridor, central-west Gansu province, northwest China It is an area of typical arid to semiarid features During the last century, especially the last half century, mankind's production activities have caused a series of detrimental environmental effects, which are summarized: water environment change, land desertification and salinization, and vegetation degeneracy Changes in the water environment include the surface water system, water quantities, continuous lowering of the groundwater table and degradation of groundwater quality Vegetation cover in the lower reaches is seriously degenerated, resulting in land desertification, salinization and dust storms Analysis indicates that the rate of the groundwater table lowering in Shiyang River basin generally exceeds 03 m/year, and the mean annual rate of groundwater decrease in Wuwei and Minqing sub-basins reaches 111–398% Until 1998, the shortage of groundwater volume was 4526×108 m3 If no effective measures are taken, this figure will be 6728×108 m3 in 2010 Remedial actions include: (1) recovery and protection of the water conservancy function of the mountain forests to ensure the sustainable development of this recharge area; (2) establishment of an authoritative agency to reasonably allocate the total water resources in Shiyang River basin; and (3) enactment of legislation and economic control to build up a water-saving society in Shiyang River basin

Preparation of novel derivatives of pyridothiazine-1,1-dioxide and their CNS and antioxidant properties.

Abstract: Starting from isothiazolopyridine-1,1-dioxide (1), corresponding derivatives of 3-aryl-4-hydroxypyrido[3,2-e]-1,2-thiazine-1,1-dioxide (6) possessing the 3-[4-(substituted-phenyl)piperazinyl]propyl or 3-(4-substituted-piperidinyl)propyl side chain by the nitrogen atom of the thiazine ring were prepared. Under pharmacological central nervous system (CNS) screening in animal models (mice), all of the six pyridothiazines 6 tested exhibited analgesic action as the predominant profile of their activity ('writhing' test 12.5-50 mg/kg). Moreover, the radical scavenging activity against peroxyl radicals of the representative pyridothiazines 6 was evaluated in vitro in water environment and some of them proved to be moderate antioxidants.

Water pollution and degradation in Pearl River Delta, South China.

Abstract: The Pearl River Delta Economic Zone is the most dynamic economic area in South China. One of the major problems in the region is the sustainable utilization of the water resources. On the basis of analysis of the water environment status and pollution sources, it is suggested that domestic sewage is the primary cause of pollution. Two new concepts "degradation coefficient" and "degradation volume" of water resources, due to pollution, which may be used to assess macroscopically the carrying capacity of the water resources and sustainability of the water environment, are proposed by the authors. The results calculated indicate that the volumes of degraded water resources will be up to 204, 352, and 537 million m3 in 2002, 2010, and 2020. It is suggested that water for daily consumption and domestic sewage must be controlled more effectively and there should be cross-regional coordination in tackling problems of water environment.

Turning type fine bubbles production apparatus

Abstract: PROBLEM TO BE SOLVED: To provide a fine bubble production apparatus with a simple structure, in which fine bubbles are efficiently produced to efficiently dissolve a gas such as air or oxygen in city water, river water or other liquid or to carry out water purification and the revival of water environment. SOLUTION: The turning type fine bubbles production apparatus is constituted of a vessel main body having a conical space 100 or a bowl or wine bottle shaped space, a pressurized liquid introducing port 50 opened in the tangential direction at a part of the inside wall circumferential surface of the space, a gas introducing port 80 opened in the bottom part 300 of the space and a turning gas liquid introducing port 101 opened at the top part of the space. COPYRIGHT: (C)2003,JPO

Late Quaternary Evolution of the Orinoco Delta, Venezuela

Abstract: The modern Orinoco Delta is the latest of a series of stacked deltas that have infilled the Eastern Venezuelan Basin (EVB) since the Oligocene. During the late Pleistocene sea-level lowstand (20,000 to 16,000 yrs BP), bedrock control points at the position of the present delta apex prevented the river channel from incising as deeply as many other major river systems. Shallow seismic data indicate that the late Pleistocene Orinoco incised into the present continental shelf, where it formed a braided-river complex that transported sediment to a series of shelf-edge deltas. As sea level rose from 16,000 to 9,500 yrs BP, the Orinoco shoreline shifted rapidly land ward, causing shallow marine waves and currents to form a widespread transgressive sand u nit. Decelerating sea -level rise and a warmer wetter climate during the early Holocene (9,500 to 6,000 yrs BP) induced delta development within the relatively quiet -water environment or the EVB embayment. Sea level approached its present stand in the middle Holocene (6,000 to 3,000 yrs BP), and the Orinoco coast prograded, broadening the delta plain and infilling the EVB embayment. Significant quantities or Amazon sediment begun to be transported to the Orinoco coast by littoral currents. Continued progradation in the late Holocene caused the constriction at Boca de Serpientes to alter nearshore and shelf hydrodynamics and subdivide the submarine delta into two distinct areas: the Atlantic shelf and the Gulf of Paria. The increased influence or littoral currents along the coast promoted mudcape development. Because most or the water and sediment were transported across the delta plain through the Rio Grande distributary in the southern delta, much or the central and northwestern delta plain became sediment starved, promoting widespread accumulation of peat deposits. Human impacts on the delta are mostly associated with the Volcan Dam on Canu Manamo. However, human activities have had relatively little effect on the delta processes and environments.

Preliminary discussion on eutrophication status of lakes,reservoirs and rivers in china and overseas

Abstract: With human's increasing development and use of environmental resources, industrial and agricultural production have rapidly expanded and developed, especially since entering new century. Industrialization results in urbanization, which a large amount of domestic sewage containing nitrogen and phosphorus are discharged into nearby lake, reservoir and river, and increase nutrient load of water bodies. For improvement of agricultural production, more and more chemical fertilizer and livestock night soil are used year after year, and thus nutrient in water increases gradually by rain scouring and penetration. Human activities that cause excess nutrients to enter water body speed up the eutrophication process. Investigation shows that about 30%～40% of the worldwide reservoirs and lakes have been eutrophied to a different extent, and lake eutrophication trends to aggravate in recent years in China, from 41% eutrophied lakes in the later 1980s to 77% in 1990s. Reservoir eutrophication is also serious, i.e. number and storage of eutrophied reservoir account for 30.8% and 11.2% of the total. In general, the extent and scope of water body trend to aggravate. Extent of eutrophication in urban lakes and reservoirs nearby city are higher than that in other region. Eutrophication in the relative still water bodies, such as lake and reservoir, is more serious than those in other regions Eutrophication in the relative stagnant water bodies, such as lakes and reservoirs, is more serious than that in rivers, but river eutrophication shouldn't neglect. Eutrophication has become one of important environment issues in world water environment protection.

Coalfield closure and the water environment in Europe

Abstract: Some of the negative consequences that coalfield closure can have for the water environment are now well documented in Western Europe, providing a useful check-list for possible eventualities during the restructuring of the coal industry in Eastern Europe. As individual mines have closed over the years the burden of dewatering has been passed on to ever fewer remaining collieries, until the last working mines in a coalfield may have to carry economically insupportable pumping rates - approaching 15 t of water pumped from the workings for every tonne of coal raised. The final closure of an entire coalfield is usually accompanied by the termination of decades (or even centuries) of regional-scale dewatering, which can have diverse consequences, including: (i) relief from some of the negative side-effects of dewatering, such as where the dewatering effluents were too saline for costeffective treatment prior to disposal; (ii) loss of some former benefits of dewatering, such as the dilution of other su...

Towards the determination of partition coefficients of cosurfactants at surfactant bilayer interfaces by muon spin resonance spectroscopy

Abstract: Avoided level crossing muon spin resonance (ALC-μSR) studies on the muonated cyclohexadienyl radical derived from the amphiphilic cosurfactant 2-phenylethanol have been used to derive cosurfactant partitioning and local environment information when dispersed in a concentrated lamellar phase dispersion. The study of partitioning at the bilayer/water interface at high surfactant concentrations is technically difficult and has consequently received very little attention. Calibration of the working range of fundamental resonance positions facilitates direct determination of cosurfactant partitioning with respect to the oil/water environment. Additional resonances yield other information about the local environment such as the degree of ordering at bilayer interfaces, thereby presenting a self-consistent picture of the local environment of the tracer molecule.

Condensed oil waste water deep treating and reusing technology

Abstract: The condensed oil waste water deep treating and reusing technology includes the technological measures of eliminating oil, eliminating suspended matter, eliminating silicon, softening slurry dewatering, etc. The oil field waste water after being deep treated may be used for refilling to low permeation oil field and in hot oil extraction boiler, and this realizes zero drainage of condensed oil waste water, protects water environment, and reaches the enclosed circulation and dynamic balance of water system in oil field. With low cost and high treating effect, the technology may be used widely in waste water treatment and reuse in oil field.

Generating new marine cell lines and transgenic species--conference summary.

Abstract: Marine species offer a tremendous diversity of life histories, physiologies, genetics, behaviors, and biologies, reflecting myriad adaptations to the water environment. Historically, marine vertebrates, particularly fish, have played significant roles in a wide range of disciplines, including environmental toxicology, genetics, developmental biology, and physiology, among others. Much still remains to be learned from these animals, and there is a growing need for new marine models. Models for expression of marine animal genes have been limited to heterologous expression systems. While there is still a great deal to gain from heterologous expression systems, the interactions of genes with one another can best be determined in homologous expression systems where appropriate interactions are possible. This has become particularly important with the development of functional genomics in marine models. These homologous gene expression systems will be key to the use of functional genomics for marine animal molecular physiology and toxicology.

Nickel-base alloy product and method of producing the same

Abstract: (1) A nickel-base alloy product having, on the surface thereof, an oxide film comprising at least two layers, namely a first layer mainly composed of Cr 2 O 3 and having a chromium content of not less than 50% relative to the total amount of metal elements and a second layer occurring outside the first layer and mainly composed of MnCr 2 O 4 , wherein the grain size of Cr 2 O 3 crystals in the first layer is 50 to 1,000 nm and the total oxide film thickness is 180 to 1,500 nm (2) A method of producing the nickel-base alloy product as specified above under (1) which comprises subjecting a nickel-base alloy product to oxide film formation treatment by maintaining the same at a temperature of 650 to 1,200° C in a hydrogen atmosphere or hydrogen-argon mixed atmosphere showing a dew point of −60° C to +20° C for 1 to 1,200 minutes The product mentioned above (1) allows only a very low level of Ni release in a high-temperature water environment over a long period of time and is particularly suited for use as a nuclear reactor member

Albumin adsorption onto pyrolytic carbon: a molecular mechanics approach.

Abstract: A number of implants of cardiac valve prosthesis, vascular prosthesis, and coronary stents present a pyrolytic carbon interface to blood. Plasma protein adsorption is essential for the hemocompatibility of the implanted devices. This work quantitatively evaluates the molecular interaction force between a biomaterial surface (pyrolytic carbon) and plasma protein (albumin) binding sites through a simplified molecular model of the interface consisting of (i) multioriented graphite microcrystallites; (ii) selected fragments of albumin; and (iii) a water environment. A number of simplifying assumptions were made in the calculation: the albumin molecule was divided into hydrophobic and hydrophilic subunits (helices); an idealized clean, nonoxidized polycrystalline graphite surface was assumed to approximate the surface of pyrolytic carbon. The interaction forces between albumin helices and pyrolytic carbon surfaces are evaluated from potential energy data. These forces are decomposed into a normal and a tangential component. The first one is calculated using a docking procedure (F⊥tot MAX = 4.16 × 10−20 N). The second one (F‖), calculated by mean of geometric models estimating the energy variation associated with the protein sliding on the material surface, varies within the range ±9.62 × 10−21 N. The molecular simulations were performed using the commercial software package Hyperchem 5.0 (Hyperchem, Hypercube, Canada). © 2001 Wiley Periodicals, Inc. J Biomed Mater Res 59: 329–339, 2002

Impacts of Change of Industrial Structure on the Water Environment in Taihu Basin: A Case Study of Suzhou-Wuxi-Changzhou District

Abstract: Since the reforming and opening up of China in 1980s, Taihu basin has witnessed great progress in social economic development and economic restructuring as well as the deterioration of water environment The paper focuses on the change of manufacturing structure and its impacts on the water environment in the Suzhou Wuxi Changzhou District It is showed that there exists certain relationship between the change of industrial structure and TP and COD in Taihu Lake, especially the manufacturing structure change in the past 20 years It is urgent to make adjustments to industry structure and reform pattern of economic development to protect water environment in Taihu Lake basin The paper also gives some suggestions about the studying on the relationship between industry structure and water environment in the future