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731.
Summary The impacts of human activities on the bio-geophysical and socio-economic environment of the Himalayas are analysed. The main man-induced activities which have accelerated ecological degradation and threatened the equilibrium of Himalayan mountain ecosystems are stated as: unplanned land use, cultivation on steep slopes, overgrazing, major engineering activities, over-exploitation of village or community forests, lopping of broad leaved plant species, shifting cultivation (short cycle) in north-east India, tourism and recreation. Monoculture in forests, erosion and landslides have resulted in one–third of the total Himalayan land area becoming environmentally derelict. Cold desert conditions prevail in 41,500 km2 of north-west Himalayas and are encouraged by traditional pasturalism. The geo-morphological conditions are major factors responsible for landslides which cause major havoc every year in the area. Other physical problems exist, such as eutrophication, drying up of the natural springs, the recession of the glaciers and changes in surface and ground water hydrology. Wild fauna, like musk deer (Moschus mischiferus) and the snow leopard (Panthera uncia), are now under threat partially due to changes in their habitat and the introduction of exotic plant species. Population pressure and migration are major factors responsible for poverty in the hills. The emigration of the working male population has resulted in the involvement of women as a major work-force. This work includes trekking for hours to collect fodder, timber and drinking water in addition to household duties. Guidelines, with special emphasis on the application of environmental impact assessments for the management of the Himalayas, are proposed.Drs Ahmad and Rawat are scientists, and Dr Rai is a research associate, at the Government of India, Ministry of Environment and Forests, G.B. Pant Institute of Himalayan Environment and Development. Correspondence should be addressed to Dr Afroz Ahmad. 相似文献
732.
733.
Mojgan Yazdi Masoud Yavarmanesh Masumeh Bahreini Mohebbat Mohebbi 《Food and environmental virology》2017,9(1):103-113
The aim of this research was to preliminary track fecal source male-specific F+RNA coliphages including human and animals in lettuce. At first, two published virus extraction procedures of ultracentrifugation and PEG precipitation were compared using DAL assay for determining the recovery efficiency in lettuce spiked artificially with three concentrations (102, 104, 106 pfu/100 ml) of MS2 coliphage. The results showed that PEG precipitation had the highest recovery in which the recovery efficiency at the spiked level of 106 pfu/100 ml was 16.63 %. Aqueous phase obtained from the final step of PEG method was applied for enumeration of coliphage and viral RNA extraction in naturally contaminated lettuce samples (N = 30) collected from two sources (market and farm). The samples were then analyzed based on (I, II, III, and IV primer sets) using RT-PCR method. Coliphages were detected in 9 (60 %) and 12 (80 %) out of 15 market and farm samples, respectively, using DAL assay, whereas male-specific F+RNA coliphages were detected using the RT-PCR method in 9 (60 %) and 13 (86.6 %) out of 15 samples of market and farm, respectively. Based on the results, only genotype I of male-specific F+RNA coliphages was detected in lettuce samples and no sample tested was positive for other genotypes (II, III, and IV). 相似文献
734.
Oxidation of sulfide in aqueous solution by hydrogen peroxide was investigated in the presence of hydrated ferric oxide catalyst. The
ferric oxide catalyst was synthesized by sol gel technique from ferric chloride and ammonia. The synthesized catalyst was characterized
by Fourier transform infrared spectroscopy, X-Ray di raction analysis, scanning electrom microscope and energy dispersive X-ray
analysis. The catalyst was quite e ective in oxidizing the sulfide by hydrogen peroxide. The e ects of sulfide concentration, catalyst
loading, H2O2 dosing and temperature on the kinetics of sulfide oxidation were investigated. Kinetic equations and activation energies
for the catalytic oxidation reaction were calculated based on the experimental results. 相似文献
735.
Megat Hanafiah Megat Ahmad Kamal Wan Mat Khalir Wan Khaima Azir MohamedKasmawati Zakaria Haslizaidi Wan Ngah Wan Saime 《环境科学学报(英文版)》2010,22(2):248-256
Rubber leaf powder (an agricultural waste) was treated with potassium permanganate followed by sodium carbonate and its
performance in the removal of Pb(II) ions from aqueous solution was evaluated. The interactions between Pb(II) ions and functional
groups on the adsorbent surface were confirmed by Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy
(SEM) coupled with X-ray energy dispersive spectroscopy (EDX). The effects of several important parameters which can affect
adsorption capacity such as pH, adsorbent dosage, initial lead concentration and contact time were studied. The optimum pH range
for lead adsorption was 4–5. Even at very low adsorbent dosage of 0.02 g, almost 100% of Pb(II) ions (23 mg/L) could be removed.
The adsorption capacity was also dependent on lead concentration and contact time, and relatively a short period of time (60–90
min) was required to reach equilibrium. The equilibrium data were analyzed with Langmuir, Freundlich and Dubinin-Radushkevich
isotherms. Based on Langmuir model, the maximum adsorption capacity of lead was 95.3 mg/g. Three kinetic models including pseudo
first-order, pseudo second-order and Boyd were used to analyze the lead adsorption process, and the results showed that the pseudo
second-order fitted well with correlation coefficients greater than 0.99. 相似文献
736.
The consumption of contaminated food crops, meat and milk has significantly increased the concentrations of trace metals in human blood as compared to the control area. 相似文献
737.
738.
A new series of 3-phenoxyazetidin-2-ones (β-lactams) were designed and synthesized for the evaluation as selective cyclooxygenase-2 (COX-2) inhibitors. In this study, the effects of a synthetic of β-lactam-structured COX-2 inhibitor with 4-(4-(methylsulfonyl)phenyl)-3-phenoxy-1-phenylazetidin-2-one on cell viability of cancerous lymphoblast isolated from patients diagnosed with acute lymphocytic leukemia (ALL) and normal lymphocytes collected from healthy donors were investigated. The viability % of cancer lymphoblast and normal lymphocyte treated 4-(4-(methylsulfonyl)phenyl)-3-phenoxy-1-phenylazetidin-2-one were tested with MTT assay. Apoptosis and necrosis were measured by double stains of annexin V and propidium iodide, and caspase-3 as a final mediator in apoptotic death measured by colorimetric assay. Mitochondria were isolated from both cancerous lymphoblast and normal lymphocytes to measure parameters of mitochondrial damage such as reactive oxygen species (ROS) formation, mitochondrial membrane potential decrease, swelling, and cytochrome c release following the administration of azithidine-2-one derivative, 4-(4-(methylsulfonyl)phenyl)-3-phenoxy-1-phenylazetidin-2-one. Our results showed that 4-(4-(methylsulfonyl)phenyl)-3-phenoxy-1-phenylazetidin-2-one inhibited proliferation of cancerous lymphoblast in a concentration-dependent manner by inducing apoptosis but not in normal lymphocytes. Treatment with azithidine-2-one derivative produced a rapid loss of mitochondrial transmembrane potential, stimulation of release of ROS and mitochondrial cytochrome c into cytosol, and subsequent induction of procaspase-9 processing. Data suggest that 4-(4-(methylsulfonyl)phenyl)-3-phenoxy-1-phenylazetidin-2-one-induced ROS production led to mitochondria-mediated death signaling that resulted in apoptosis in cancerous lymphoblast cells. The induction of apoptosis by azithidine-2-one compounds, such as 4-(4-(methylsulfonyl)phenyl)-3-phenoxy-1-phenylazetidin-2-one, may provide a mechanism for its cancer chemopreventive action in acute lymphocytic leukemia cells. 相似文献
739.
740.
Haoran Dong Guangming Zeng Chang Zhang Jie Liang Kito Ahmad Piao Xu Xiaoxiao He Mingyong Lai 《环境科学学报(英文版)》2015
This study investigated the interaction between Cu2 + and nano zero-valent iron (NZVI) coated with three types of stabilizers (i.e., polyacrylic acid [PAA], Tween-20 and starch) by examining the Cu2 + uptake, colloidal stability and mobility of surface-modified NZVI (SM-NZVI) in the presence of Cu2 +. The uptake of Cu2 + by SM-NZVI and the colloidal stability of the Cu-bearing SM-NZVI were examined in batch tests. The results showed that NZVI coated with different modifiers exhibited different affinities for Cu2 +, which resulted in varying colloidal stability of different SM-NZVI in the presence of Cu2 +. The presence of Cu2 + exerted a slight influence on the aggregation and settling of NZVI modified with PAA or Tween-20. However, the presence of Cu2 + caused significant aggregation and sedimentation of starch-modified NZVI, which is due to Cu2 + complexation with the starch molecules coated on the surface of the particles. Column experiments were conducted to investigate the co-transport of Cu2 + in association with SM-NZVI in water-saturated quartz sand. It was presumed that a physical straining mechanism accounted for the retention of Cu-bearing SM-NZVI in the porous media. Moreover, the enhanced aggregation of SM-NZVI in the presence of Cu2 + may be contributing to this straining effect. 相似文献