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581.
Holth TF Beckius J Zorita I Cajaraville MP Hylland K 《Marine environmental research》2011,72(3):127-134
There is a need for sensitive biological effect methods by which to detect impacts of chronic exposure to low concentrations of contaminants. Two methods shown to be potentially useful for monitoring purposes in fish include lysosomal membrane stability and peroxisome proliferation. These biological endpoints were assessed in Atlantic cod (Gadus morhua) head kidney following exposure to a mixture of produced water components including polycyclic aromatic hydrocarbons, phenol, and alkylphenols. Lysosomal damage of head kidney cells occurred within the first two weeks and did not recover during the entire exposure period (32 weeks). Lysosomal membrane stability was not affected by gender and was responsive at low concentrations of contamination, indicating that lysosomal membrane stability measured in the head kidney could be a useful biomarker for effects of offshore pollution. Peroxisome proliferation, measured as acyl-CoA oxidase activity in the head kidney, appeared to be a potential biomarker in male cod exposed less than 16 weeks. 相似文献
582.
B. S. K. REDDY K. R. KUMAR G. BALAKRISHNAIAH K. R. GOPAL R. R. REDDY V. SIVAKUMAR S. Md. ARAFATH A. P. LINGASWAMY S. PAVANKUMARI K. UMADEVI Y. N. AHAMMED 《大气科学进展》2013,30(1):235-246
Surface measurements of aerosol physical properties were made at Anantapur(14.62°N,77.65 °E,331 m a.s.l),a semiarid rural site in India,during August 2008-July 2009.Measurements included the segregated sizes of aerosolsas as well as total mass concentration and size distributions of aerosols measured at low relative humidity(RH<75%) using a Quartz Crystal Microbalance(QCM) in the 25-0.05 μm aerodynamic diameter range.The hourly average total surface aerosol mass concentration in a day varied from 15 to 70 μg m-3,with a mean value of 34.02±9.05μgm-3 for the entire study period.A clear diurnal pattern appeared in coarse,accumulation and nucleation-mode particle concentrations,with two local maxima occurring in early morning and late evening hours.The concentration of coarse-mode particles was high during the summer season,with a maximum concentration of 11.81±0.98μgm-3 in the month of April,whereas accumulationmode concentration was observed to be high in the winter period contributed >68% to the total aerosol mass concentration.Accumulation aerosol mass fraction,A f(=Ma/Mt) was highest during winter(mean value of Af~0.80) and lowest(Af~0.64) during the monsoon season.The regression analysis shows that both R eff and R m are dependent on coarse-mode aerosols.The relationship between the simultaneous measurements of daily mean aerosol optical depth at 500 nm(AOD500) and PM 2.5 mass concentration([PM2.5]) shows that surface-level aerosol mass concentration increases with the increase in columnar aerosol optical depth over the observation period. 相似文献
583.
Viral nervous necrosis(VNN)has emerged to become a major problem in the culture of larval and juvenile marine fish worldwide.Bioactive phytochemicals isolated from commonly available medicinal plants are often screened for their efficacy in controlling fish viral diseases.Occurrence of newer viral strains and resistance to existing antiviral drugs are problems currently as-sociated with treatment of VNN,which necessitates looking for alternate sources for effective antiviral drugs.The aim of the present study was to screen antiviral potential of gymnemagenol(C30H50O4)previously extracted from leaves of Gymnema sylvestre.The fish nodavirus,grouper nervous necrosis virus(GNNV)in infected Sahul Indian Grouper Eye(SIGE)cell lines were used to study the antiviral activity of gymnemagenol under in vitro conditions.The susceptibility of the virus to gymnemagenol was confirmed by measuring the viral titre(TCID50 mL?1)in virus-infected SIGE cells every 24 h.Gymnemagenol at 20 μg mL?1 inhibited the prolifera-tion of GNNV to 53% at the end of the 6th d by inhibiting the proliferation of GNNV-infected SIGE cells.The viable SIGE cells were reduced to 47% as determined by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT)assay.The viral titre(TCID50 mL?1)was also reduced to log 2.8 at the end of the 7th d in gymnemagenol-treated SIGE cells after inoculated with GNNV when compared to untreated control SIGE cell viral titre(log 4.1).Based on our results it can be concluded that gymnemagenol could be used as an antiviral agent against GNNV infection. 相似文献
584.
The Ca II K filtergrams from Kodaikanal Solar Observatory have been used to study solar activity.The images are dominated by the chromospheric network and plages.Programs have been developed to obtain the network and plage indices from the daily images as functions of solar latitude and time.Preliminary results from the analysis are reported here.The network and plage indices were found to follow the sunspot cycle.A secondary peak is found during the period of declining activity in both the indices.A comparison of network indices from the northern and the southern hemispheres shows that the former is more active than the latter.However such an asymmetry is not clearly seen in the plage index. 相似文献
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587.
The results obtained from an investigation of suspended particulate matter in the metropolitan city of Lahore (Pakistan) are reported and analysed in this paper. X-ray diffraction studies of the airborne matter collected from various urban and suburban sites show that non-clay minerals such as quartz, calcite and albite are contained in most of the samples in almost comparable amounts. Chemical analysis of some samples was carried out for complementing the x-ray diffraction data. The amount of quartz in the samples of dusty areas was found to be an order of magnitude more than in the samples of relatively cleaner areas. As the dust particles of these compounds are poor substrate for promoting nucleation of ice in the atmospheric clouds, they are liable to stay steadily in the atmosphere as pollutants.A comparison of the results of the airborne particulates and the soil samples collected from various sites show that the sources of quartz, calcite and albite in the airborne matter are both local and remot 相似文献
589.
本文第1部份,描述从SAS-2卫星得到的能量大于100MeV的宇宙Υ射线数据来证认有Υ射线的活动星系核。11个类星体、3个BLLac天体和1个射电星系的Υ射线辐射已得到证认。 本文第2部分描述活动星系核对河外Υ射线背景辐射的影响。SAS-2的Υ辐射数据,已被用来测定类星体和赛弗特星系的Υ辐射绝对光度与光学绝对光度间的函数关系,并由此导出它们对河外Υ射线背景辐射的贡献。我们指出,类星体(B<20)、赛弗特星系(1型和1.5型)对35—100MeV能量范围的弥散Υ射线背景辐射有相当大的贡献(59%)。由此我们得出河外Υ射线背景辐射可能是由类星体和赛弗特星系这类活动星系产生的结论。 本文第3部份我们对3个有Υ辐射的活动星系核综合其Υ波段和其他波段的数据,以探索这些天体辐射的发射机制。这些综合的数据对发射机制给出严格的限制。我们指出,对这3个天体的数据,与同步自康普顿模型(SSC)的预计是一致的。 相似文献
590.
Compositional data on the sterol and alcohol fractions isolated from deep-sea marine sediments from the Okinawa Trough were obtained to determine the relative contribution from. marine and terrestrial inputs. Following extraction, the sterol plus alcohol fraction was isolated by layer chromatography, derivatized with BSTFA and then analysed by capillary GC and GC-MS. A suite of C26-C29 stenols and stanols and C30-C32 keto - alcohols were identified in the sediments. The thermal stability of the compounds in these sediments was studied by heating portions of the surface sediment in glass tubes fpr 16 hours at temperatures from 50℃ to 200℃.The C27 stanol/stenol ratio increased when temperatures went up to 175℃ , but the distribution of C30-C32 Keto - alcohols remained unaffected. At 200℃ most of the sterols and Keto - alcohols were destroyed. 相似文献