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1.
Environmental Science and Pollution Research - Aedes aegypti and Culex quinquefasciatus are vectors of diseases that constitute public health problems. The discovery of products capable of...  相似文献   

2.
Mosquitoes transmit dreadful diseases, causing millions of deaths every year. Therefore, screening for larvicidal and pupicidal activity of microbial extracts attributes could lead to development of new and improved mosquito control methods that are economical and safe for nontarget organisms and are ecofriendly. Synthetic chemical insecticides occupy predominant position in control strategies. These hazardous chemicals exert unwarranted toxicity and lethal effects on nontarget organisms, develop physiological resistance in target, and cause adverse environmental effect. For vector control, fungal-mediated natural products have been a priority in this area at present. In the current study, effective larvicidal and pupicidal effect of mycosynthesized silver nanoparticles (Ag NPs) using an entomopathogenic fungi Trichoderma harzianum against developmental stages of the dengue vector Aedes aegypti was investigated. An attractive possibility of green nanotechnology is to use microorganisms in the synthesis of nanosilver especially Ag NPs. The mycosynthesized Ag NPs were characterized to find their unique properties through UV-visible spectrophotometer, X-ray diffraction analysis, Fourier transform infrared, and surface characteristics by scanning electron microscopy. To analyze the bioefficacy, different test concentrations for extracellular filtrate (0.2, 0.4, 0.6, 0.8, and 1.0 %) and Ag NPs (0.05, 0.10, 0.15, 0.20, and 0.25 %) were prepared to a final volume of 200 mL using deionized water; 20 larvae of each instars (I–IV) and pupa were exposed to each test concentration separately which included a set of control (distilled water) group with five replicates. Characterization of the synthesized Ag NPs were about 10–20 nm without aggregation. Susceptibility of larval instars to synthesized Ag NPs was higher than the extracellular filtrate of T. harzianum alone after 24-h exposure, where the highest mortality was recorded as 92 and 96 % for first and second instars and 100 % for third, fourth instars, and pupa. Lethal concentration 50 values of 0.079, 0.084, 0.087, 0.068, and 0.026 % were recorded for I–IV instars and pupa, respectively, when exposed to Ag NPs at 0.25 % concentration. Toxicity was exhibited against first (1.076 %), second (0.912 %), third (0.770 %), fourth (0.914 %) instars larvae, and pupa (0.387 %) with extracellular filtrate at a concentration of 1 % that was three- to fourfold higher compared to Ag NPs; no mortality was observed in the control. The present study is the first report on effective larvicidal and pupicidal activity of Ag NPs synthesized from an entomopathogenic fungi T. harzianum extracellular filtrate and could be an ideal ecofriendly, single-step, and inexpensive approach for the control of A. aegypti.  相似文献   

3.
With the aid of integral transforms, analytical solutions for the transport of a decay chain in homogenous porous media are derived. Unidirectional steady-state flow and radial steady-state flow in single and multiple porosity media are considered. At least in Laplace domain, all solutions can be written in closed analytical formulae. Partly, the solutions can also be inverted analytically. If not, analytical calculation of the steady-state concentration distributions, evaluation of temporal moments and numerical inversion are still possible. Formulae for several simple boundary conditions are given and visualized in this paper. The derived novel solutions are widely applicable and are very useful for the validation of numerical transport codes.  相似文献   

4.
Environmental Science and Pollution Research - The control of storage insect pests is largely based on synthetic pesticides. However, due to fast growing resistance in the targeted insects,...  相似文献   

5.
Environmental Science and Pollution Research - Plastic usage increases year by year, and the growing trend is projected to continue. However as of 2017, only 9% of the 9 billion tons of plastic...  相似文献   

6.
从南京禄口水产养殖基地淡水鱼塘取淤泥作为分离菌株的土源,采用选择性富集培养法,从中分离到能以硫酸铵为氮源的菌株7株,对7个菌株进行氨氮降解实验,它们氨氮转化率分别为14.8%、19.7%、53.4%、94.2%、29.1%、63.5%和41.7%,其中AN-4菌株的转化率最高且生长良好。通过AN-4菌株16S rRNA基因序列分析以及生理生化方法,鉴定此菌株为克雷伯氏菌属(Klebsiellasp.)。对菌株AN-4转化氨氮的特性及温度、pH值、氨氮初始浓度和菌株接种量对其氨氮转化率的影响研究,结果表明,菌株AN-4降解氨氮的最适条件为:温度为30℃和pH值为8.0;当氨氮初始浓度为30mg/L时,AN-4菌株在24 h内的氨氮降解率可达85%以上,且能耐受高达200 mg/L的氨氮浓度;AN-4活化菌液浓度为108cfu/mL,当接种量为3×106cfu/mL时,AN-4菌株在24 h内的氨氮降解率为87.75%。综合上述结果,符合淡水养殖水环境条件,说明AN-4菌株适合在水产养殖中应用,为将菌株AN-4应用于水产养殖环境修复提供了理论依据。  相似文献   

7.
8.
Direct measurement of arsenic release requires a good sampling and analysis procedure in order to capture and detect the total amount of metals emitted. The literature is extensively reviewed in order to evaluate the efficiency of full field-scale and laboratory scale techniques for capturing particulate and gaseous emissions of arsenic from the thermo-chemical treatment of different sources of arsenic. Furthermore, trace arsenic concentrations in ambient air, national standard sampling methods and arsenic analysis methods are considered. Besides sampling techniques, the use of sorbents is also reviewed with respect to both approaches (1) to prevent the metals from exiting with the flue gas and (2) to react or combine with the metals in order to be collected in air pollution control systems. The most important conclusion is that submicron arsenic fumes are difficult to control in conventional air pollution control devices. Complete capture of the arsenic species requires a combination of particle control and vapour control devices.  相似文献   

9.
Some of pathogenic bacteria and fungi have the ability to produce fetal toxins which may be the direct causes of cytotoxicity or cellular dysfunction in the colonization site. Biological and non-biological environmental factors, challenge and microbes influence the effect of toxins on these pathogens. Modern research mentions that many natural materials can reduce the production of toxins in pathogenic microbes. However, researches that explain the mechanical theories of their effects are meager. This review aimed to discuss the ameliorative potential role of plant-derived compounds and probiotics to reduce the toxin production of food-borne microbes either in poultry bodies or poultry feedstuff. Moreover, studies that highlight their own toxicological mechanisms have been discussed. Adding natural additives to feed has a clear positive effect on the enzymatic and microbiological appearance of the small intestine without any adverse effect on the liver. Studies in this respect were proposed to clarify the effects of these natural additives for feed. In conclusion, it could be suggested that the incorporation of probiotics, herbal extracts, and herbs in the poultry diets has some beneficial effects on productive performance, without a positive impact on economic efficiency. In addition, the use of these natural additives in feed has a useful impact on the microbiological appearance of the small intestine and do not have any adverse impacts on intestinal absorption or liver activity as evidenced by histological examination.  相似文献   

10.
室内霉菌污染原因及其控制对策   总被引:3,自引:0,他引:3  
通过对建筑墙体内湿气迁移过程的研究,详细分析了霉菌污染产生的原因。通过夏、冬两季平均气候条件下沿墙厚度温度、相对湿度分布和湿积累量的具体计算,得出墙内的相对湿度将达到或超过70%,有时甚至处于饱和状态,从而为霉菌的生长提供了有利条件。基于分析结果,提出了对于室内霉菌污染的控制对策。  相似文献   

11.
Environmental Science and Pollution Research - Pollution control policies have achieved remarkable results in China. However, industrial firms still lack enthusiasm for technological innovation to...  相似文献   

12.
冷轧生产过程中,带钢表面的氧化铁皮由于振动而在车间发生沿程脱落,车间扬尘污染问题严重,影响工人的身体健康和产品的质量.用于带钢氧化铁皮除尘的吹吸式尘源控制技术,利用喷嘴产生的高速射流将带钢上下表面松动的氧化铁皮粉尘清除,使粉尘在源头脱落,并随高速气流运动,经吸气罩排走.基于计算流体力学基本理论,应用CFX计算软件,选择...  相似文献   

13.

Background, aim, and scope  

Arthropods, with over a million species described, are ubiquitous throughout different environments. Knowledge of their responses to human impact is crucial for understanding and predicting changes in ecosystem structure and functions. Our aim was to investigate the general patterns and to identify sources of variation in changes of the diversity, abundance and fitness of terrestrial arthropods (including Arachnida, Collembola and Insecta) in habitats affected by point polluters.  相似文献   

14.
With the goal in mind to minimize the application of environmentally hazardous chemical insecticides, the larvicidal activity of two plant extracts along with deltamethrin was studied at University of Mysore. The extracts of Solidago canadensis and Eugenia jambolana were employed for working out the synergistic efficacy against Aedes aegypti larvae, as the extracts of both the plants exhibited high efficacy when applied individually. The deltamethrin when analyzed separately, LC50 and LC90 values were 0.00045 and 0.00148 ppm, respectively. Synergistic studies with two plant extracts on deltamethrin revealed S. canadensis as more effective with synergistic factor(SF) of 4.090 for LC50 value and 4.781 for LC90 followed by E. jambolana with SF 1.80 for LC50 and 2.467 for LC90 at 1:1 ratio of the phytoextracts and deltamethrin. Thus, S. canadensis was found to be a better larvicidal and synergistic agent. Combination of phytochemical and insecticide were found to be more effective than insecticides or phytochemicals alone which could be a good ecofriendly and cost-effective approach to reduce the dose of chemicals with high residual effect to be applied in vector control programs.  相似文献   

15.
Environmental Science and Pollution Research - A study area was selected from the industrial region of Gaoshawo Town, Yanchi County, Ningxia, to explore the level of heavy metal pollution in desert...  相似文献   

16.
对上海市二十余年畜禽养殖污染治理实践经验和启示进行回顾与评价,探讨了当前畜禽规模养殖污染治理项目的管理需求,并结合上海市十二五期间畜禽规模养殖污染现状特征及减排形势,研究了适于畜禽规模养殖污染治理的项目管理机制,包括项目实施管理和工程建成运行监管,为工程推进实施和长效稳定运行提供技术保障,确保其长期发挥生态环境效益。  相似文献   

17.
Human populations are using oceans as their household dustbins, and microplastic is one of the components which are not only polluting shorelines but also freshwater bodies globally. Microplastics are generally referred to particles with a size lower than 5 mm. These microplastics are tiny plastic granules and used as scrubbers in cosmetics, hand cleansers, air-blasting. These contaminants are omnipresent within almost all marine environments at present. The durability of plastics makes it highly resistant to degradation and through indiscriminate disposal they enter in the aquatic environment. Today, it is an issue of increasing scientific concern because these microparticles due to their small size are easily accessible to a wide range of aquatic organisms and ultimately transferred along food web. The chronic biological effects in marine organisms results due to accumulation of microplastics in their cells and tissues. The potential hazardous effects on humans by alternate ingestion of microparticles can cause alteration in chromosomes which lead to infertility, obesity, and cancer. Because of the recent threat of microplastics to marine biota as well as on human health, it is important to control excessive use of plastic additives and to introduce certain legislations and policies to regulate the sources of plastic litter. By setup various plastic recycling process or promoting plastic awareness programmes through different social and information media, we will be able to clean our sea dustbin in future.  相似文献   

18.
Plant susceptibility to acidifying atmospheric pollution was investigated for a wide range of plant species under normal environmental conditions. Physiological and biochemical parameters were recorded for each plant species. Multivariate analysis using hierarchical clustering, principal component analysis ordination, as well as regression analysis were used to interpret the data. Analysis of the data separated plants into pioneer tree species, ruderal herbaceous species and climax, slow growing species. Pioneer and ruderal species showed higher potential for foliar nitrate assimilation coupled with higher base cation content and a tendency to a more neutral leaf pH than climax species. Acidic buffering capacities for leaf tissue from pioneer and ruderal species were higher than those of climax species. Nitrate assimilation produces hydroxyl ions, which in conjunction with high base cation content and more neutral leaf pH, provides better metabolic buffering and therefore make pioneer and ruderal species less susceptible to acidifying inputs. Climax species are less able to buffer against acidifying inputs and are subsequently more prone to acidifying air pollution damage.  相似文献   

19.
Environmental Science and Pollution Research - In this editorial trend, we aim to collect and present recently available data about the characteristics of SARS-CoV-2 virus, severity, infection,...  相似文献   

20.
机动车尾气排放是城市大气污染的重要来源,介绍了美国对机动车尾气控制管理的先进经验。首先美国建立了以《清洁空气法》为核心、多项法律为支撑的法律体系,将机动车与燃料作为一个系统,制定容易实施的燃料标准和污染物排放标准,并从能源效率控制、生产过程管理、在用车辆管理等多方面实施机动车污染控制的全过程管理。此外,在实施过程中,美国环境保护署和交通运输部紧密配合,职责分工明确,共同推动机动车污染控制,针对不同阶段的污染特征,逐步调整控制重点。在分析美国经验的基础上,结合中国目前机动车污染现状,从立法层面、管理手段、管理机构等方面对中国的机动车污染控制提出了相关对策建议。  相似文献   

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