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191.
The in vivo toxic impact of chromium in its two forms (trivalent and hexavalent) on glycogen metabolism in the liver and kidney of a fresh water teleost Anabas scandens was studied. In a sub-chronic exposure of 30 days, depletion of glycogen and glucose reserves reflected in the activity patterns of glycogen phosphorylases a and ab. While both forms of chromium induced alterations in enzyme activities and metabolite levels in the two tissues, Cr+6 exerted greater effects in the kidney.School of Life Sciences, University of Hyderabad, Hyderabad - 500 134, India 相似文献
192.
Estuarine sediments in the<63 μm size fraction were collected from 15 stations within the Tambaraparni River Estuary, located on the east coast of India. The distribution of the heavy metals Cd, Co, Cr, Cu, Ni, Pb and Zn was recorded. Our analysis distinguished two groups of elements. First, Cd, Pb and Zn, which occurred in higher than expected concentrations indicative of pollution, and second, Co, Cr, Cu and Ni, which occurred at background levels. The highest metal concentration found in the study area was for Zn (1200 μ g·g?1), and the lowest was for Cd (0.42 μ g·g?1). It is presumed that river run-off, industrial waters and untreated domestic waters are major contributors to heavy metal pollution in the Tambaraparni River Estuary. The concentrations of heavy metal species in surface sediments (<2 m water depth) of the Tambaraparni Estuary were studied to determine the extent of anthropogenic inputs from catchment areas and to understand anthropogenic effects on geochemical process in this tropical estuarine system. 相似文献
193.
The photocatalytic degradation of the herbicide isoproturon under solar light was investigated in aqueous solution containing a Bi–TiO2/zeolite photocatalyst. The catalysts were characterized using X-ray diffraction, UV-Vis diffuse reflectance spectroscopy, Fourier transform-infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy. The effect of Bi–TiO2 loading onto the zeolite support and influence of the parameters such as catalyst amount, pH, and initial concentration of isoproturon on the degradation rate were evaluated. The recycling ability of the catalyst was found to be sustainable for elongated periods. The high activity of the Bi–TiO2/zeolite was attributed to its absorptivity of visible light and its high adsorption capacity for the pollutant molecules. 相似文献
194.
For the first time, gliadin films with excellent strength and water stability have been developed without using any crosslinking
agents. So far, it has not been possible to obtain water stable gliadin films even after crosslinking. In this research, a
novel method of using aqueous urea and ethanol has been developed to obtain highly water stable gliadin films without using
crosslinking chemicals. The effects of concentrations of gliadin, urea and ethanol on the strength of the films and the stability
of the films in water at high temperatures and various pH conditions has been studied. Gliadin films developed in this research
have strength of about 30 MPa similar to the strength of previously reported gliadin films crosslinked with aldehydes and
cysteine. Gliadin films obtained in this research were stable in pH 7.2 water at 50 °C for 20 days. The gliadin films did
not dissolve in 70% ethanol which readily dissolves gliadin powder. 相似文献
195.
S. Aulong B. Chaudhuri L. Farnier S. Galab J. Guerrin H. Himanshu P. Prudhvikar Reddy 《Regional Environmental Change》2012,12(3):423-436
Global changes are already having an impact on South Indian farmers. Climate change is affecting the agricultural sector since it is dependent on climatic conditions and water resource availability. The impacts tend to be greater in semi-arid hard rock areas with few water resources. Furthermore, South India area is experiencing a profound agrarian crisis, which is linked, among others, to debt and credit problems. The study reported in this paper aims to develop a methodology to compare and rank farmers according to their ability to adapt to global change. The definition of adaptive capacity is based on a livelihood assets approach. Indicators are evaluated through individual surveys among farmers, then, weighted using the analytic hierarchy process and aggregated via compromise programming. The result is a standardized score measuring the distance of each farmer from an ideal adaptive capacity. Farmers are ranked according to this distance, which allows a comparison of their relative ability to adapt. At the basin scale, it shows that the geographic position of farmers is a significant factor in adaptation performance. The proximity of an administrative center contributes to an increase of their adaptive capacity. Small farming areas limit the adaptive capacities of marginal and small farmers while the largest farmers are constrained by economic factors such as large loans. These study findings offer interesting indications on the variability of farmers’ weaknesses and are bringing a better understanding of the causes of poor performance. 相似文献
196.
Physiological responses of glyphosate-resistant and glyphosate-sensitive soybean to aminomethylphosphonic acid, a metabolite of glyphosate 总被引:2,自引:0,他引:2
Aminomethylphosphonic acid (AMPA) is formed in glyphosate-treated glyphosate-resistant (GR) and glyphosate-sensitive (GS) soybean [Glycine max (L.) Merr.] plants and is known to cause yellowing in soybean. Although, AMPA is less phytotoxic than glyphosate, its mode of action is different from that of glyphosate and is still unknown. Greenhouse studies were conducted at Stoneville, MS to determine the effects of AMPA on plant growth, chlorophyll content, photosynthesis, nodulation, nitrogenase activity, nitrate reductase activity, and shoot nitrogen content in GR and GS soybeans. AMPA was applied to one- to two-trifoliolate leaf stage soybeans at 0.1 and 1.0 kg ha(-1), representing a scenario of 10% and 100% degradation of glyphosate (1.0 kg ae ha(-1) use rate) to AMPA, respectively. Overall, AMPA effects were more pronounced at 1.0 kg ha(-1) than at 0.1 kg ha(-1) rate. Visual plant injury (18-27%) was observed on young leaves within 3d after treatment (DAT) with AMPA at the higher rate regardless of soybean type. AMPA injury peaked to 46-49% at 14 DAT and decreased to 17-18% by 28 DAT, in both soybean types. AMPA reduced the chlorophyll content by 37%, 48%, 66%, and 23% in GR soybean, and 17%, 48%, 57%, and 22% in GS soybean at 3, 7, 14, and 28 DAT, respectively. AMPA reduced the photosynthesis rate by 65%, 85%, and 77% in GR soybean and 59%, 88%, and 69% in GS soybean at 3, 7, and 14 DAT, respectively, compared to non-treated plants. Similarly, AMPA reduced stomatal conductance to water vapor and transpiration rates at 3, 7, and 14 DAT compared to non-treated plants in both soybean types. Photosynthesis rate, stomatal conductance, and transpiration rate recovered to the levels of non-treated plants by 28 DAT. Plant height and shoot dry weight at 28 DAT; nodulation, nitrogenase activity at 10 DAT, and nitrate reductase activity at 3 and 14 DAT were unaffected by AMPA. AMPA reduced root respiration and shoot nitrogen content at 10 DAT. These results suggest that a foliar application of AMPA could indirectly reduce photosynthesis through decreased chlorophyll content in GR and GS soybean up to 14 DAT, but affected plants can recover to normal growth by 28 DAT. 相似文献
197.
Reddy MS Okuda T Nakai S Nishijima W Okada M 《Waste management (New York, N.Y.)》2011,31(8):1848-1851
Wet gravity separation technique has been regularly practiced to separate the polypropylene (PP) and polyethylene (PE) (light plastic films) from chlorinated plastic films (CP films) (heavy plastic films). The CP films including poly vinyl chloride (PVC) and poly vinylidene chloride (PVDC) would float in water even though its density is more than 1.0 g/cm3. This is because films are twisted in which air is sometimes entrapped inside the twisted CP films in real existing recycling plant. The present research improves the current process in separating the PP and PE from plastic packaging waste (PPW), by reducing entrapped air and by increasing the hydrophilicity of the CP films surface with ozonation. The present research also measures the hydrophilicity of the CP films.In ozonation process mixing of artificial films up to 10 min reduces the contact angle from 78° to 62°, and also increases the hydrophilicity of CP films. The previous studies also performed show that the artificial PVDC films easily settle down by the same. The effect of ozonation after the wet gravity separation on light PPW films obtained from an actual PPW recycling plant was also evaluated. Although actual light PPW films contained 1.3% of CP films however in present case all the CP films were removed from the PPW films as a settled fraction in the combination process of ozonation and wet gravity separation. The combination process of ozonation and wet gravity separation is the more beneficial process in recovering of high purity PP and PE films from the PPW films. 相似文献
198.
Adoption and adaptation of natural resource management innovations in smallholder agriculture: reflections on key lessons and best practices 总被引:2,自引:0,他引:2
Bekele A. Shiferaw Julius Okello Ratna V. Reddy 《Environment, Development and Sustainability》2009,11(3):601-619
Many smallholder farmers in vulnerable areas continue to face complex challenges in adoption and adaptation of resource management
and conservation strategies. Although much has been learned from diverse experiences in sustainable resource management, there
is still inadequate understanding of the market, policy and institutional failures that shape and structure farmer incentives
and investment decisions. The policy and institutional failures exacerbate market failures, locking smallholder resource users
into a low level equilibrium that perpetuates poverty and land degradation. Improved market access that raises the returns
to land and labor is often the driving force for adoption of new practices in agriculture. Market linkages, access to credit
and availability of pro-poor options for beneficial conservation are critical factors in stimulating livelihood and sustainability-enhancing
investments. Future interventions need to promote joint innovations that ensure farmer experimentation and adaptation of new
technologies and careful consideration of market, policy and institutional factors that stimulate widespread smallholder investments.
Future projects should act as ‘toolboxes’, giving essential support to farmers to devise complementary solutions based on
available options. Addressing the externalities and institutional failures that prevent private and joint investments for
management of agricultural landscapes will require new kinds of institutional mechanisms for empowering communities through
local collective action that would ensure broad participation and equitable distributions of the gains from joint conservation
investments.
Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue. 相似文献
199.
Marco-Urrea E Parella T Gabarrell X Caminal G Vicent T Adinarayana Reddy C 《Chemosphere》2008,70(3):404-410
The white-rot fungus Trametes versicolor degraded trichloroethylene (TCE), a highly oxidized chloroethene, and produced 2,2,2-trichloroethanol and carbon dioxide as the main products of degradation, based on the results obtained using [13C]-TCE as the substrate. For a range of concentrations of TCE between 2 and 20 mg l(-1), 53% of the theoretical maximum chloride expected from complete degradation of TCE was observed. Laccase was shown to be induced by TCE, but did not appear to play a role in TCE degradation. Cytochrome P-450 appears to be involved in TCE degradation, as evidenced by marked inhibition of degradation of TCE in the presence of 1-aminobenzotriazole, a known inhibitor of cytochrome P-450. Our results suggested that chloral (trichloroacetaldehyde) was an intermediate of the TCE degradation pathway. The results indicate that the TCE degradation pathway in T. versicolor appears to be similar to that previously reported in mammals and is mechanistically quite different from bacterial TCE degradation. 相似文献
200.
ABSTRACT: A closed form solution is presented for determining the shape and location of the interface between two dissimilar fluids (having different densities) when steady flow takes place through a homogeneous and isotropic porous medium, into a sheetpile cofferdam; the interface is assumed to be sharp and the lower fluid stationary. The solution is obtained using the inverse hodograph. Numerical results are presented in nondimensional form for various parametric conditions in the physical plane; the interface pattern, as also the seepage discharge and exit gradient distribution are shown. The critical conditions of the interface are studied. 相似文献