共查询到20条相似文献,搜索用时 15 毫秒
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Antineoplastic platinum complexes represent new-developed inorganic cytostatics, which interfere with intracellular nucleic acids, especially with DNA. The main representative is cis-diamminedichloroplatinum (II) (cis-platin, DDP). It has proven effective against human urogenital tumors and against carcinomas of the head and neck. The most severe side effects are nephrotoxicity and gastrointestinal irritation. Stimulated by the clinical success of cisplatin, a series of platinum complexes of the second generation has been recently developed. Moreover, anti-tumor properties were detected for various organometallic complexes containing titanium, vanadium, tin, or iron as central atoms. 相似文献
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A review on usnic acid,an interesting natural compound 总被引:1,自引:0,他引:1
Lichens are a world-widespread consortium of fungal and photosynthetic partners. Usnic acid is one of the most common and abundant lichen metabolites, well known as an antibiotic, but also endowed with several other interesting properties. This review summarises the most relevant studies on usnic acid, focusing on a number of biological activities in different fields. On the basis of the existing literature, usnic acid seems to be an exclusive lichen product. No synthetic derivatives more effective than the natural form are known. Both the (+) and (-) enantiomers of usnic acid are effective against a large variety of Gram-positive (G+) bacterial strains, including strains from clinical isolates, irrespective of their resistant phenotype. Of particular relevance is the inhibition of growth of multi-resistant strains of Streptococcus aureus, enterococci and mycobacteria. The (+)-usnic acid enantiomer appears to be selective against Streptococcus mutans without inducing perturbing side effects on the oral saprophyte flora. On the other hand, the (-)-usnic acid enantiomer is a selective natural herbicide because of its blocking action against a specific key plant enzyme. Other recognised characteristics of usnic acid are ultraviolet absorption and preserving properties. The toxicology, the in vitro anti-inflammatory effects and the mechanism of action of usnic acid need to be investigated in greater detail in order to reach clinical trials and to allow further applications. Furthermore, more research is needed to make possible intensive lichen culture, in order to produce large quantities of lichen substances for pharmaceutical, cosmetic and agricultural purposes. Some biological aspects, i.e. the possible biological roles of usnic acid, are discussed. 相似文献
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《Journal of Cleaner Production》2007,15(13-14):1287-1294
Although there is a pragmatic side of nanotechnology, active and applicable today, its possible applications in the paper industry, especially in emissions reduction and dematerialisation, have attracted only limited consideration.Nanotechnology plays a major role in the development of new products to substitute existing production equipment, materials and chemicals with improved performance resulting in potential environmental and cost savings. Reduced consumption of materials also benefits the environment. Moreover, nanotechnology gives possibilities to organise and develop production processes in a more sustainable way—eventually as close to the zero-emissions approach as possible.This study looks at the current role of nanotechnology in the paper industry and its possible future implications with an analysis of both challenges and opportunities with respect to environmentally sound papermaking and consumer concerns such as health effects. 相似文献
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气候作为人类生存活动与发展的支撑,其变化也必然对城市"社会-经济-自然"复合生态系统的各个方面产生影响。另一方面,城市建设过程中通过人口增长、经济发展、空间扩张、资源能源消耗等对气候变化产生反作用,以定性与定量分析相结合的方法建立了城市系统与气候变化耦合关系指标,以南京市为例运用Spearman相关系数构建城市系统与气候变化交互作用的相关耦合关系模型,定量揭示出两者耦合的关系。 相似文献
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David H. Kingsley 《Food and environmental virology》2013,5(1):1-12
High pressure processing (HPP) is an increasingly popular non-thermal food processing technology. Study of HPP’s potential to inactivate foodborne viruses has defined general pressure levels required to inactivate hepatitis A virus, norovirus surrogates, and human norovirus itself within foods such as shellfish and produce. The sensitivity of a number of different picornaviruses to HPP is variable. Experiments suggest that HPP inactivates viruses via denaturation of capsid proteins which render the virus incapable of binding to its receptor on the surface of its host cell. Beyond the primary consideration of treatment pressure level, the effects of extending treatment times, temperature of initial pressure application, and matrix composition have been identified as critical parameters for designing HPP inactivation strategies. Research described here can serve as a preliminary guide to whether a current commercial process could be effective against HuNoV or HAV. 相似文献
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This study investigates the effects of four different variables (initial workpiece temperature, side rake angle, edge radius/feed rate, and nose radius/depth of cut) on ductile regime machining of a bioceramic material known as nanohydroxyapatite (nano-HAP) using 3D numerical simulation. AdvantEdge FEM Version 5.9 is used to conduct turning simulations of the nano-HAP workpiece. Tecplot 360 is used to analyze the results of the simulations. Because the workpiece is thin, the entire workpiece is set to a uniform initial temperature to simulate laser preheating of the material. Initial workpiece temperature, rake angle (side rake angle), edge radius, and nose radius are varied, and the effects of these operating conditions on critical feed are investigated. It is found that critical feed increases as initial workpiece temperature increases, and also as negativity of rake angle increases. For the edge radius, it is concluded that an initial increase causes an increase in critical feed – however, at some value of edge radius, critical feed shows no further increase; for the nose radius, critical feed appears to show no significant dependence. 相似文献
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《Environmental Science & Policy》2003,6(2):167-174
Environmental measures have sometimes unintended side effects. The paper focuses on side effects that are the result of relations and feedback mechanisms between economic activities and industries in production–consumption chains. The theoretical framework of the chain analysis tools, life cycle assessment and substance flow analysis is used to define five different types of environmental measures: volume measures (1), efficiency measures (2), end-of-pipe emission reduction measures (3), re-use and recycling (4) and useful application of waste products (5). Each of these types of measures can re-direct substance flow in a different process, thus causing pollutant emissions to the environment to shift to similar or other emissions upstream or downstream in the economic chain. Using this categorization, the occurrence of a number of different processes that can lead to side effects can be predicted. 相似文献
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《环境科学学报(英文版)》2023,35(7):128-138
Bacterial infections have become a great threat to public health in recent years. A primary lysozyme is a natural antimicrobial protein; however, its widespread application is limited by its instability. Here, we present a poly (N-isopropylacrylamide) hydrogel inverse opal particle (PHIOP) as a microcarrier of lysozyme to prolong and enhance the efficiency against bacteria. This PHIOP-based lysozyme (PHIOP-Lys) formulation is temperature-responsive and exhibits long-term sustained release of lysozyme for up to 16 days. It shows a potent antibacterial effect toward both Escherichia coli and Staphylococcus aureus, which is even higher than that of free lysozyme in solution at the same concentration. PHIOPs-Lys were demonstrated to effectively inhibit bacterial infections and enhance wound healing in a full-thickness skin wound rat model. This study provides a novel pathway for prolonging the enzymatic activity and antibacterial effects of lysozyme. 相似文献
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Katsuyuki Nakano 《Mitigation and Adaptation Strategies for Global Change》2018,23(3):433-449
The primary vector of the dengue fever virus, the Aedes aegypti mosquito, is distributed across the tropical and sub-tropical latitudes; however, the area at risk of infection has been expanding steadily. This study aimed to identify the industries most vulnerable to the effects of dengue fever by 2030. The assessment was done by considering the international supply chain, with aspects such as the labor intensity, and the relevant geographical and socioeconomic aspects being taken into account. In addition, multi-regional input-output tables were employed to analyze the ripple effects of productivity losses resulting from workers contracting the disease. The results indicate that more than 10% of the workers involved in the supply chain of all the major industries in the United States (USA), China, Japan, and Germany could be considered at risk of contracting dengue fever by 2030. Moreover, the risk was even higher in India and Brazil, namely, more than 70%. The effect of widespread dengue fever infection could influence industrial activities severely, not only in the regions most at risk (India and Brazil) but also in the other regions (USA, Japan, and Germany). Labor-intensive industries, such as agriculture, fisheries, and the distribution sector are particularly at risk and will have to consider appropriate contingency measures. It is recommended that the downstream side of the supply chain, the industries in the USA, Japan, and Germany, supports the introduction of worker’s health management system against the infectious disease into their business partners. This study employed limited data and only estimated the possible effects of the disease by 2030. Further comprehensive analysis is required with more data modeled for the future to verify and enhance the reliability of the present results. 相似文献
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彭友德 《安全.健康和环境》2002,2(1):11-14
针对消防水系统存在的问题,进行了系统可靠性分析.从提高系统可靠性方面,提出了优化消防水系统结构,提高系统可靠性的改造方案,并论证实施后的效果. 相似文献
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Francisco Sánchez Carmi Korine Burt P. Kotler Berry Pinshow 《Die Naturwissenschaften》2008,95(6):561-567
Ethanol occurs in fleshy fruit as a result of sugar fermentation by both microorganisms and the plant itself; its concentration [EtOH] increases as fruit ripens. At low concentrations, ethanol is a nutrient, whereas at high concentrations, it is toxic. We hypothesized that the effects of ethanol on the foraging behavior of frugivorous vertebrates depend on its concentration in food and the body condition of the forager. We predicted that ethanol stimulates food consumption when its concentration is similar to that found in ripe fruit, whereas [EtOH] below or above that of ripe fruit has either no effect, or else deters foragers, respectively. Moreover, we expected that the amount of food ingested on a particular day of feeding influences the toxic effects of ethanol on a forager, and consequently shapes its feeding decisions on the following day. We therefore predicted that for a food-restricted forager, ethanol-rich food is of lower value than ethanol-free food. We used Egyptian fruit bats (Rousettus aegyptiacus) as a model to test our hypotheses, and found that ethanol did not increase the value of food for the bats. High [EtOH] reduced the value of food for well-fed bats. However, for food-restricted bats, there was no difference between the value of ethanol-rich and ethanol-free food. Thus, microorganisms, via their production of ethanol, may affect the patterns of feeding of seed-dispersing frugivores. However, these patterns could be modified by the body condition of the animals because they might trade-off the costs of intoxication against the value of nutrients acquired. 相似文献
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《Journal of Cleaner Production》2007,15(13-14):1373-1381
This paper presents four strategic approaches for sustainable regional development: The Natural Step Framework, Zero Emissions, Eco-Industrial Parks, and The Rocky Mountains Institute's Economic Renewal program. An analysis against the requirements of regional planning shows a great synergy potential among these concepts. A joint approach would be advisable, not only on the content side, as the presented concepts differently fulfil the requirements of regional planning, but also on the organisational side, in terms of coordinating efforts and allocating personnel, time and financial resources. However, all four concepts seem to lack two aspects: First, a project must meet the needs of the residents and fit their regional and personal identities in order to get them involved, and second, most development projects need clear monitoring structures. In order to close these gaps, we propose to integrate a tool that helps to understand people's livelihood systems, as well as monitoring tools such as Ecological Footprint accounts, Factor X models or Material Impact calculations. 相似文献
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Lake Maryout is an important fishing lake lining Alexandria City, Egypt at its southern side. It has no direct connection with the Mediterranean Sea. Most of the landed fish come from its Main Basin (one of the lakes four sub-basins). This basin, area 6000 acres, since the sixties of the last century is suffering from pollution as it receives untreated sewage and industrial effluents from Alexandria City at four hot spots, distributed along the coasts of its eastern half. This has led to a noticeable decline with time in the quantity and quality of the fish catch and to subsequent social and economic problems to the fishermen. In a solution for these problems the government has erected two treatment plants in 1993 to primary treat these waste effluents before discharging into this Main Basin at only two sites. One at a (an old) site lies at its southeast side where one of the plants discharges is indirectly reaching the lake via an agricultural drain while the other plant discharge is directly flowing at a new site lies at the lake northwest side. Obviously the other three old hot spots are completely blocked. Water (on monthly basis) and sediment samples were collected from the Main Basin as well as from the other basins of the lake to study the state of the water quality and level of some priority metal pollutants in addition to organic carbon (org-C) in the sediments of the lake after the erection of the two treatment plants. The results reveal that the water at the (north) eastern side of the Main Basin gets improvement while that in front of the new site at its northwest side becomes polluted and its sediments become enriched with the studied metals (Ag, As, Sb, Cr, Hg, Ni, (Pb), Cd, Zn and Cu). The enrichment was more noticeable for the (spoiled) sediments in front of all the old hot spots in addition to those off the new source. Also, this basin as a whole still shows remarkable high levels of sewage indicating elements including nutrients, organic carbon, fecal coliform, biochemical oxygen demand (BOD), chemical oxygen demand (COD) and hydrogen sulfide (H2S) simultaneously with noticeable low levels of total dissolved solids and dissolved oxygen relative to the other lake basins. The last basins are in healthy conditions as they only fed with agricultural drainage waters free from the treatment plants effluents. The elevated concentrations particularly for the last six studied metals in the sediments are found to be at levels comparable to their corresponding of the median effect-range of Long and Morgan recommended by the U.S. Environmental Protection Agency (EPA), that may have possible effect on bottom fauna and other organisms (including edible fish) live in this polluted basin. This situation makes this important lake basin as a dangerous source for health-hazard fish. Suggested solutions are presented here for rehabilitation of the lake and its sediments. The most accepted ones by the government include diversion of the sources simultaneously with dredging of the spoiled sediments and advanced treatments of the effluents to reuse them for irrigation of reclaimed neighboring desert lands. 相似文献