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1.
Blood lead concentrations, estimated in epidemiological surveys of adult women in Wales, have shown a fall of over 30% since 1972. During the same period the amount of lead in petrol has changed little but general traffic flow has steadily increased; there has been no change in the amount of lead in water.  相似文献   

2.
Summary Oleic acid esterification by ethanol has been performed by an immobilized lipase fromMucor miehei in supercritical carbon dioxide and in n-hexane as solvents. In both media, determination of apparent kinetic constants has been achieved and influence of water content has been shown to be different due to various rates of water solubilities. Stability of the lipase has been proved to be correct and similar in both solvents. Inhibition by ethanol excess has been found but is greater in n-hexane. That can explain the higher initial velocities obtained in supercritical carbon dioxide for the highest ethanol concentrations.  相似文献   

3.
Recent advances in fetal nucleic acids in maternal plasma.   总被引:7,自引:0,他引:7  
The discovery of cell-free fetal DNA in maternal plasma in 1997 has opened up new possibilities for noninvasive prenatal diagnosis. Circulating fetal DNA molecules have been detected in maternal plasma from the first trimester onwards and can be robustly detected using a variety of molecular methods. This approach has been used for the prenatal investigation of sex-linked diseases, fetal RhD status, and prenatal exclusion of beta-thalassemia major. Recently, fetal RNA has also been found in maternal plasma. Such fetal RNA has been shown to originate from the placenta and to be remarkably stable. The use of microarray-based approaches has made it feasible to rapidly generate new circulating RNA markers. It is hoped that further developments in this field will make the routine and widespread practice of noninvasive nucleic acid-based prenatal diagnosis for common pregnancy-associated disorders feasible in the near future.  相似文献   

4.
A. K. Basu 《Genetica》1996,97(3):279-290
Genetic research on cotton in India in recent times is reviewed. Establishment of a gene bank with global accessions of the four cultivated species, as well as wild relatives, has facilitated genetic improvement of cotton in India. Genetic control of the economic traits has been studied by biometrical approaches, particularly the line x tester analysis, diallel cross and generation mean analysis. Both additive and non-additive gene actions have been reported for most of the traits. Heritability estimates are low to high. Studies on G×E interaction and stability parameters indicate availability of lines which are stable in their performance over locations and seasons. Genetic improvement of yield, fibre properties, lint percent, seed oil, earliness and resistance to key pests and diseases has been targeted and considerable success has been achieved. Single cross, three-way cross, multiple cross, back cross, biparental mating, mutation breeding and heterosis breeding are the main procedures employed for improvement of yield. Heterosis breeding has, however, made the most significant contributions in improvement of both yield and fibre quality in recent times. While resistant genotypes have been developed for most of the pests and diseases, resistance against cotton bollworms has not been achieved. Genetic engineering to incorporate the Bt gene in cotton to impart resistance to bollworms is in progress. Keeping in view the increased requirements of cotton in the future, thrust areas in genetic research have been indicated.  相似文献   

5.
异养鞭毛虫原位生长研究进展   总被引:2,自引:0,他引:2  
近年来,异养鞭毛虫随水体生态内浮游动物小型化进程的加剧,所占比重越来越,已成为当前生态学研究的重要对象,其研究方法也伴随着发生了革命性变化,通过简单介绍异养鞭毛虫的原位研究方法,并就近来研究成果进行了系统综述。  相似文献   

6.
The emergence of 'shotgun proteomics' has paved the way for high-throughput proteome analysis, by which thousands of proteins can be identified simultaneously from complex samples. Although the shotgun approach has the potential to monitor many different post-translational modifications, further technological development is needed to enrich each post-translational 'modificome'. Large-scale in vivo phosphorylation site mapping, so-called shotgun phosphoproteomics, has become feasible in various organisms, including plants, owing to recent technological breakthroughs. Shotgun phosphoproteomics is not a mature technology, but progress has been rapid. In this review, we highlight the scope and limitations of current methods, and some key technological issues in this field.  相似文献   

7.
The water quality of Lake Geneva has declined steadily since the 1960s, due to a continuous increase of external phosphorus loading. Average P level in the lake increased steadily to a peak in 1979, and even 1981 in the case of P content in the trophogenic layer. Since then, reduced external inputs related to the delayed effects of phosphorus removal from waste waters initiated many years previously has led to a decrease in P level, and resulted in present stabilization and even improvement in water quality. Long-term changes in zooplankton abundance correspond quite closely to eutrophication level changes. After increasing since the 1960s, maximum zooplankton biomass was recorded for the first time in 1971; a second main peak appeared in 1981 together with the highest eutrophication level. Over the last seven years, zooplankton abundance has decreased continuously, while water transparency has decreased and phytoplankton production has remained at a high level.  相似文献   

8.
Although the philosophy of the community mental health center has been applied to alcoholism since the early part of this decade, it has been pursued much more intensively in recent years, and there has been a decentralization in the management of alcoholics in a series of stages from the jail or work-house to the state hospital and to the clinic and the community. The medical practitioner now has opportunity to treat the alcoholic in private practice.Advances have been made in two directions. Advances in medical management have included reinforcement of the importance of hydration and electrolyte balance, particularly magnesium. Psychopharmacology has contributed three drugs particularly important in the management of acute alcoholism and its complications. These drugs are chlordiazepoxide, chlorpromazine, and thioridazine. Another drug, Antabuse, when properly used, has proven extremely valuable as a deterrent.Equally important have been administrative advances. The importance of the environment and its manipulation has been recognized, and a series of institutional and non-institutional resources, such as clinics, half-way houses, foster homes, and Alcoholics Anonymous has made it less likely that a patient will be turned away without help.  相似文献   

9.
Many years of study were devoted to fructicose flora of plantings in the city of Vladivostok. Species diversity bearing on the type of planting has been studied. Contribution of each species to the city’s landscaping has been assessed quantitatively. The vitality of shrubs has been diagnosed and their stability in the conditions of urban ecosystems has been estimated.  相似文献   

10.
《Plains anthropologist》2013,58(83):29-34
Abstract

The study of diseases, anomalies and abnormalities in skeletal or mummified bodies representing peoples of the past, has been the stepchild of Archaeology and medical pathology for many years. In the past the emphasis has been on documentation of unusual findings. Little effort has been made to educate researchers and teachers in this field. A course of instruction in Paleopathology was held for 4 years at the U.S. National Museum. In an assessment of the teaching of Paleopathology in North America Kerley found that 68 of 340 anthropology departments and museums with physical anthropology sections offered such courses. There was considerable variation in the organization of the courses, material covered, teaching aids available, instruction methods, and the general orientation of the instruction. In 1972 a course in Paleopathology was first offered at the University of Tennessee-Knoxville and has continued since. The problem of communicating concepts of pathology, epidemiology, and demography to inexperienced university students has necessitated continuing modification of the course. Education in Paleopathology has received little emphasis in the past. Our teaching methods may be of value to others. We are documenting our experiences with the hope that they are helpful and that in the future there may be increased interest in and some standardization of teaching methods.  相似文献   

11.
Recent trends in functional food science and the industry in Japan   总被引:2,自引:0,他引:2  
International recognition of functional foods has resulted in the recent global development of this field, which originated in Japan. The national policy on functional foods, in terms of "foods for specified health use", also has been developing and has motivated the food industry to produce a variety of new food items. In Japan as well as in many other countries, academic and industrial scientists have been working in collaboration for the analysis and practical applications of functional food science. Emphasis has been placed on the study of antioxidant and anticarcinogenic food factors as well as pre- and probiotics. This review pinpoints recent trends in the science and industry in this field.  相似文献   

12.
The effect of a virulent S. typhimurium strain and its cAMP-deficients mutant on the level of cAMP in macrophages in the process of phagocytosis has been studied. The virulent strain has been shown to induce the 3-fold increase of the level of cAMP in macrophages, while the mutant renders no such effect.  相似文献   

13.
A method of analysis for comparing the variability of two samples drawn from two populations has been developed. The method is also suitable for the nonnumeric form of data. A test based on ordered observations for testing the null hypothesis of equality of two variances has been given. The test statistic is a function of the sum of ranks assigned to smaller size sample. Ranking procedure has been modified to depict the variability in the data by the sum of ranks. The null distribution of the test-statistic has been worked out for small samples and it turns out to be chi-square distribution for large samples. The analytical procedure has been explained by a numerical example on the productivity and production of rice and wheat in India from 1950–51 to 1983–84.  相似文献   

14.
The relaxation-activation autoregulative method (RAM) is a psychoregulative procedure characterized by typical autonomic patterns of relaxation and activation phases (blood pressure, electric skin resistance, heart beat, EEG, etc.). They are used as feedback information in the training of autoregulative abilities. RAM has a multidimensional (non-specific) tuning effect which is manifested by changes in the psychophysiological state (emotional tuning, physiological functioning and performance). It has a therapeutical effect on disorders with a psychic pathogenic component, e.g., essential hypertension. The increased production of adrenaline following the application of RAM was found in previous experiments.--The present experiment with a sample of six persons well mastering RAM has shown that the cortisol level following this psychoregulative intervention also rises significantly and that this rise has been recorded over three days, i.e., over the whole period of saliva sampling. It may be said that RAM has a non-specific, ergotropic (activating) subsequent effect and that this effect has the character of stress, more accurately eustress. Autogenic training, on the other hand, reduces the cortisol level.  相似文献   

15.
An effect of isosorbide dinitrate on blood pressure values in the pulmonary circulation and the right heart has been investigated in 25 patients with a history of the first transmural myocardial infarction. Group I including 12 patients has been given 5 mg isosorbide nitrate in a 60-minute intravenous infusion while group II of 13 patients has been given 10 mg of the drug in the same way. Both groups have been matched in clinical data and blood pressure value in the pulmonary circulation which has been normal. Pulmonary blood pressure has been measured with Swan-Ganz catheter prior to the administration of drug, and 15, 30, 45 and 60 minutes following an infusion. Isosorbide dinitrate in a dose of 5 mg did not decrease blood pressure in the pulmonary circulation statistically significantly. The differences in blood pressure falls did exceed 9%. Filling pressure in the right ventricle did not change either while systolic blood pressure decrease by 16.6%. A double dose of isosorbide dinitrate reduced blood pressure in the pulmonary artery by about 1/3 of the baseline value, and blood pressure in the right ventricle (mean right atrial pressure) by 57.2%. Both systolic and diastolic arterial pressures were reduced. Isosorbide dinitrate reduced blood pressure in the pulmonary circulation in patients who underwent myocardial infarction, and hypotensive effect has been dose-related. A reduction in the right ventricular filling pressure has been a one of important mechanisms decreasing pulmonary pressures.  相似文献   

16.
17.
Autophagy: in sickness and in health   总被引:36,自引:0,他引:36  
The degradation of intracellular components in lysosomes (autophagy) has recaptured the attention of cell biologists in recent years. The main reason for this renewed interest is the dissection of the molecular machinery that participates in this process, because the identification of new intracellular elements involved in autophagy has provided new tools to trace, quantify and manipulate autophagy in a growing number of organisms. As a result, a better understanding of the physiological roles of autophagy, the consequences of its malfunctioning and its participation in different pathological processes has emerged. This article reviews our current knowledge of the role of autophagy in disease and the efforts to reconcile its proposed dual function as both a cell protector and a cell killer.  相似文献   

18.
观赏植物花期调控途径及其分子机制   总被引:4,自引:0,他引:4  
王翊  马月萍  戴思兰 《植物学报》2010,45(6):641-653
开花期控制对观赏植物的生产和应用具有重要意义。目前关于高等植物成花机理的研究已经取得了突破性进展, 为观赏植物花期调控开辟了新途径。该文总结了观赏植物花期调控的途径和方法, 并对改良观赏植物花期的技术思路做了初步分析。通过与高等植物成花机制研究的对比分析发现, 观赏植物开花机理的研究已有了长足发展, 一些观赏植物的转基因研究也取得了丰硕成果。利用分子设计育种途径改良观赏植物的开花期, 突破了传统方法的局限性, 其研究和应用前景非常广阔。  相似文献   

19.
Progress in biosensors has mainly been made by the improvement of the biological components and the implementation of microsystem technologies. Enzymes are still the most appropriate recognition elements because they combine high chemical specificity and inherent biocatalytic signal amplification. A breakthrough has been achieved in the application of membrane-integrated receptor systems for analyte recognition and signal transduction in biosensors. Sensor integration of RNA aptamers has been initiated, and the performance of fully synthetic molecularly imprinted polymers has been improved.  相似文献   

20.
The state of skin microcirculation system has been studied in healthy volunteers aged from 20 to 77, using laser Doppler flowmetry. To reveal the reaction of microvascular bed in response to short-term ischemia, occlusive test has been carried out. During experiment the age-induced reduction of microcirculation index has been observed at rest. In response to stopping occlusion the 3.5--4-aliquot increase of microcirculation index has been revealed during reactive post-occlusive hyperemia in all age groups. The data obtained suggest maintenance of high reserve resources of skin microcirculation in ageing in response to ischemia.  相似文献   

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