The aim of this study was to determine whether there is increased leakage of neuron-specific enolase (NSE) and S-100 protein into amniotic fluid in pregnancies with neural tube defects, since both these proteins are produced by neural tissue, and to compare the value of these substances for detecting such defects with that of the more conventional techniques of alpha-fetoprotein (AFP) and acetylcholinesterase (AChE) gel electrophoresis. Amniotic samples from 25 mid-pregnancies (15–17 weeks' gestation) with neural tube defects (14 with open spina bifida and 11 with anencephaly) and from seven mid-pregnancies with abdominal wall defects were compared with a control material consisting of 80 amniotic fluid samples from 80 consecutive mid-pregnancy amniocenteses, with normal karyotypes and AFP concentrations. All of the above cases of abnormalities were primarily detected through increased AFP levels in the amniotic fluid. Amniotic fluid samples from 13 pregnancies with fetuses with autosomal chromosomal abnormalities and seven amniotic fluid samples contaminated with blood were also included in the investigation. It is concluded from the results that the conventional AFP assay combined with AChE gel electrophoresis is the best method for screening amniotic fluid for neural tube defects and defects of the abdominal wall. Neither NSE nor S-100 assay alone proved to be superior for the detection of these cases in mid-trimester amniotic fluid. The S-100 assay, however, could give additional information in cases where AChE gel electrophoresis is not decisive; for example, in samples contaminated with blood. 相似文献
Environmental psychology research in Sweden is reviewed beginning with studies in the 1960s. The traditional main foci of the Swedish research are the visual perception of form, space, colour, and texture, the meaning of social and physical environments; and the effects of the indoor and outdoor ambient environment (noise, air quality and temperature). More recent research foci include environmental cognition (perceptual categorization, cognitive mapping, orientation, planning), affective reactions to the environment, and systems applications. It is concluded that the Swedish research is integrated with environmental psychology research in other countries in terms of a common data base and methodology, despite the fact that the problems investigated are to some extent national in tone. It is also pointed out that the Swedish research appears to have the potential of theoretical contributions to environmental psychology, which is badly needed within the field as a whole. 相似文献
A bacterial strain was isolated from activated sludge and has been identified as Pseudomonas sp. S-42 capable of decolorizing azo dyes such as Diamira Brilliant Orange RR (DBO-RR), Direct Brown M (DBM), Eriochrome Brown R (EBR) and so on. The growing cells, intact cells, cell-free extract and purified enzyme of strain S-42 could decolorize azo dyes under similar conditions at the optimum pH 7.0 and temperature of 37℃. The efficiencies of decolorization for DBO-RR, DBM, EBR with intact cells stood more than 90%. When the cell concentration was 15mg (wet)/ml and the reaction time was 5 hours, the decolorizing activities of intact cells for above three azo dyes were 1.75, 2.4, 0.95 μg dye/mg cell, respectively. Cell-free extract and purified enzyme belonged to azoreductase with molecular weight about 34000±2000 and Vmax and Km values for DBO-RR of 13μmol/mg protein/nun and 54μmol, respectively. The results from the detection of the biodegradation products of DBO-RR by spectrophotometric and NaNO2 reaction methods showed that the biodegradation of azo dyes was initiated by the reducing cleavage of azo bonds. The biodegradation metabolism path for DBO-RR by Psued. S-42 was hypothesized. 相似文献
This paper presents a numerical study involving the deformation of contact faces in the metal-to-metal seal in a typical pressure relief valve. The valve geometry is simplified to an axisymmetric problem, which comprises a simple geometry consisting of only 3 components. A cylindrical nozzle, which has a valve seat on top, contacts with a disk, which is preloaded by a compressed linear spring. All the components are made of AISI type 316N(L) steel defined using the multilinear kinematic hardening model based on monotonic and cyclic tests at 20° C. In-service observations show that there is a limited fluid leakage through the valve seat at operational pressures about 90% of the set pressure, which is caused by the fluid penetrating into surface asperities at the microscale. Nonlinear FEA in ANSYS using the fluid pressure penetration (FPP) technique revealed that there is a limited amount of fluid penetrating into gap, which is caused by the plastic deformation of the valve seat at the macroscale. Prediction of the fluid pressure distribution over the valve seat just before the valve lift is addressed in this study considering the FPP interaction on multiscale. This is the principal scope, since it allows adjustment of the valve spring force in order to improve the leak tightness. 相似文献
Some of the challenges of BGT were answered by two multi-disciplinary projects of the ICMR on Pathology and Toxicology and Pathophysiology. Unlike other chemical disasters, the aerosol inhaled by the Bhopal victims contained a mixture of MIC and its trimers and dimers, as well as aqueous and thermal decomposition products, including HCN. A coordinated GC–MS study of the blood and autopsy tissues and chemicals in the Tank residue confirmed their role.
Autopsy studies revealed the pathological changes in the acute, sub-acute and chronic phases progressive changes of pulmonary edema and bronchiolitis, followed by chronic pulmonary fibrosis. Cerebral edema resulted in ‘acute histotoxic anoxia’. Intensive experimental studies with the help of newer tools of molecular biology might throw more light on the underlying mechanisms and newer therapeutic approaches.
The initial finding of cherry-red discoloration of lungs led to a suspicion of cyanide toxicity. Eventually, elevated blood and tissue cyanide levels confirmed the prompt therapeutic response to NaTS and accompanying increase of urinary NaSCN excretion. However, periodic clinical recurrences and relapses pointing towards ‘chronic cyanide toxicity’ remained enigmatic.
Specific changes the 2–3 DPG levels and Blood Gases were explained on the basis of N-carbamoylation of end-terminal valine residues of Hb. Soon, several other end-terminal -amino groups of tissue proteins were also found to be N-carbamoylated. Had the attempts at demonstrate S-carbamoylation of glutathione and other SH radicals of tissue enzymes like rhodanese succeeded, perhaps the underlying mechanism of chronic cyanide toxicity due to MIC might have been resolved.
Based on the practical lessons learnt in Bhopal, an attempt will be made to present the salient pathological and toxicological findings, followed by a brief outline of the principles of planned laboratory management for alleviation of human suffering from future chemical disasters. 相似文献
Cooling water is used by many industrial facilities. The largest user of cooling water is the electric power industry, although other significant users include the pulp and paper, chemical, iron and steel, aluminum, and petroleum refining industries. The US Environmental Protection Agency (EPA) is currently developing regulations to implement section 316(b) of the Clean Water Act, which deals with cooling water intake structures. The EPA will examine cooling water use patterns at various industries. Data pertaining to cooling water use patterns at utility plants are readily available; however, no information has been assembled for cooling water use at electric power generating facilities owned or operated by entities other than utilities (nonutilities). This paper presents data concerning cooling water use from two subsets of the nonutility sector and focuses on plants using once-through cooling systems. The first subset includes 123 nonutility plants that each generate at least 150 MW of power. Collectively, they represent 41,494 MW of generating capacity, or about 56% of the total nonutility generating capacity. Approximately 17% of the installations within that subset utilize once-through cooling water. The second subset includes 58 waste-to-energy facilities, which individually produce less than 80 MW but collectively generate about 2200 MW. Only 11% of this subset of plants uses once-through cooling water. The total 15,372 MW generated by once-through nonutilities is equivalent to only 6% of the 258,906 MW generated by utilities utilizing once-through cooling. From a national perspective this share may appear relatively insignificant. However, in some states, the nonutility once-through total is equivalent to a more significant percentage of the utility once-through total. 相似文献