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51.
52.
In vitro fertilization (IVF) is one of the most important treatments of infertility to provide a chance of conceiving. In IVF treatment, sperm are washed and motile sperm are isolated with sperm washing media (SWM) for the purpose of fertilization; fertilized ova are then incubated for a maximum of 5 or 6 d in media for IVF (IVFM). The exposure of fertilized ova to chemicals via such media has not been studied. We determined the concentrations of two contaminants; di(2-ethylhexyl)phthalate (DEHP) and its hydrolyzed product mono(2-ethylhexyl)phthalate (MEHP) in IVFM, SWM, and protein sources (PS: human serum albumin or serum substitute) for IVFM and SWM. The DEHP and MEHP in these media were extracted by a liquid-liquid extraction method and their concentrations determined by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Fifteen IVFM, nine SWM, and six PS obtained in Japan were examined. The concentrations of DEHP and MEHP in IVFM and SWM were <10-114 and <2.0-263 ng mL−1, respectively. The concentrations of both DEHP and MEHP were higher in the media containing PS than in those without PS. Either MEHP alone or both DEHP and MEHP were detected in PS. The concentrations of DEHP and MEHP in PS were <10-982 and 47.0-1840 ng mL−1, respectively. The DEHP and MEHP detected in these media were derived from PS. This is the first study on the chemical contamination of IVFM, SWM, and PS.  相似文献   
53.
Here we propose a method to quantitatively assess and examine Global No Net Loss (GNNL) of forest biodiversity on a global scale. The method produces a GNNL index of existing forest and enables future predictions of forest loss under different assumptions. The method tests the feasibility of the GNNL index and enables discussion of policy for future global scale sustainable forest management up to 2050. The GNNL index was estimated from an equation including forest areas per country per forest type (primary forest, secondary forest and plantation forest), diversity of forest ecosystem, and species density. Estimates derived from historical data revealed an approximate 7% reduction in GNNL index between 1990 and 2005. Predictions of the GNNL index until 2050 emphasize the importance of regenerating large portions of forests felled for agricultural land (or other uses) with secondary forests.  相似文献   
54.
This study focused on steam gasification and reforming of waste biomass using a reforming catalyst. The purpose of the study was to evaluate the durability of a commercial Ni reforming catalyst and the effect of CaO on the reforming behavior, and to clarify detailed factors of catalytic performance, as well as the effect of operating parameters on the characteristics of produced gas composition. Moreover, catalyst regeneration was carried out and the behavior of catalytic activity based on gas composition was investigated. Using a fluidized bed gasifier and a fixed bed reformer, gasification and reforming of waste biomass were carried out. Commercial Ni-based catalyst and calcined limestone (CaO) were applied to the reforming reaction. Temperature of the gasifier and reformer was almost 1023 K. Ratio of steam to carbon in the feedstock [mol mol−1] and equivalence ratio (i.e., ratio of actual to theoretical amount of oxygen) [-] were set at about 2 and 0.3, respectively. The feed rate of the feedstock into the bench-scale gasifier was almost 15 kg h−1. The results of waste biomass gasification confirmed the improvement in H2 composition by the CO2 absorption reaction using the reforming catalyst and CaO. In addition, CaO proved to be especially effective in decreasing the tar concentration in the case of woody biomass gasification. Catalytic activity was maintained by means of catalyst regeneration processing by hydrogen reduction after air oxidation when woody biomass was used as feedstock.  相似文献   
55.
There is a strong need for the development of relatively rapid and low-cost bioassays for the determination of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and dioxin-like polychlorinated biphenyls (dl-PCBs) in environmental and food samples. In this study, we applied a reporter gene assay using DR-EcoScreen cells (DR-cell assay), which is highly sensitive to dioxins, to the determination of PCDD/Fs and dl-PCBs in fish and seafood samples. The PCDD/Fs and dl-PCBs were extracted from homogenated samples (10 g) of 30 fish and shellfish, purified by clean-up procedure using a multilayered silica gel column and an alumina column, and applied to DR-cell assay. Interestingly, the bioanalytical equivalent (BEQ) values obtained from the DR-cell assay [<0.1 ∼ 5.4 pg BEQ g−1 wet weight (ww)] were closely correlated with the toxicity equivalent (TEQ) values from conventional high-resolution gas chromatography/high-resolution mass spectrometry (HRGC-HRMS) analysis (r2 = 0.912), and the slope of regression line was 0.913. Therefore, we multiplied the BEQ values from the DR-cell assay by a conversion coefficient (1.095, the reciprocal of 0.913) to approximate the TEQ values from the HRGC-HRMS analysis. Furthermore, we used this DR-cell assay to perform a prescreening test of PCDD/Fs and dl-PCBs in 16 fish and seafood samples purchased from a supermarket, revealing that a sample from the fatty flesh of a bluefin tuna exceeded 8 pg TEQ g−1 ww (the European Union-tolerance limit). Taken together, these results suggest that the DR-cell assay might be applicable as a rapid and low-cost prescreening method to determine dioxin levels in fish and seafood samples.  相似文献   
56.
Many of the new particle sizing instruments utilize light scattering principles to detect and size aerosolparticles. The sensitivity of such nstruments is quite good, although extensive light shielding and focusingmethods must be used. A visible He-Ne gas laser cavity with its low gain is very sensitive to disturbances in its optical cavity and so may provide a new particle sizing approach.  相似文献   
57.
ABSTRACT

This study investigated spatio-temporal variations of selected pesticide residues in the Kurose River in Higashi-Hiroshima city (Hiroshima Prefecture), Japan. Water samples were collected from the river at seven sites every month for 1 year (March 2016 to February 2017). Pesticide residues were extracted from the samples by a solid phase extraction using Sep Pack C18 cartridges. Once extracted, the samples were analyzed for cyanazine, simetryn, fenarimol, isoprothiolane, and diazinon using a reversed-phase high-performance liquid chromatography ultraviolet visible (HPLC-UV Vis) system. The limits of detection were 3.60, 4.10, 2.80, 6.50, and 7.30 ng L-1 for cyanazine, simetryn, fenarimol, isoprothiolane, and diazinon, respectively. Good recovery rates (88%–102%), and mean percent relative standard deviation range (1.00%–5.70%) (n = 6) were obtained with a spiking at 0.20 µg L-1. The maximum concentrations of 282, 391, 60, 1086, and 1194 ng L-1 were obtained for cyanazine, simetryn, isoprothiolane, fenarimol, and diazinon, respectively. Cyanazine was the most frequently detected pesticide (64% of the samples, n = 84), followed by simetryn (58%), and then diazinon (57%). The highest and lowest pesticide concentrations were measured during the periods May–June, and January–February, respectively. Principal component analysis revealed three principal components in which the pesticides were linked to dissolved organic matter and total suspended solids. The major water quality parameters (electrical conductivity, pH, Na+, K+, Mg2+, Ca2+, NH4+, NO3?, Cl?, SO42?, NO2?, and temperature) showed no clear trends for these pesticides. The presence of simetryn and isoprothiolane was largely attributed to rice paddy farms, whereas diazinon was associated mostly with vegetable farms and orchards. The diazinon and isoprothiolane patterns were consistent with their use of controlling insects and fungi in the prefecture. The maximum diazinon concentration detected was higher than the human safe level specified by the European Union (100 ng L-1) in Council Directive 98/83/EC. This is of concern because of the bioconcentration potential of these residues in fish and other marine animals consumed by humans.  相似文献   
58.
Sri Lanka being an agrarian country, the role of water is important for agricultural production. In Sri Lanka, various tank cascade systems, earthen dams and distribution canals have been accepted as few of the most complex ancient traditional water systems of the world. Rainfall, surface water, groundwater and runoff are linked with each other, they have close interactions to land cover classes such as forests and agriculture. The monitoring of vegetation conditions can show subsurface manifestations of groundwater. In this study, an effort to understand the role of traditional water reservoirs and groundwater recharge was made using remote sensing techniques. We have analyzed various vegetation indices such as Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI-2), Soil-Adjusted Vegetation Index (SAVI), tasselled cap transformation analysis (TCA brightness, greenness and wetness) and their relations with the existence of soil, vegetation and water. Result shows that EVI, SAVI, and TCA-based Greenness Index indicates good relationship with the vegetation conditions as compared to other indices. Therefore, these indices could play a crucial role in depicting the interaction between soil, vegetation, and water. However, multi-temporal observations can provide significant results about these interactions more accurately.  相似文献   
59.
We investigated the respiratory uptake kinetics of polychlorinated biphenyls (PCBs), organohalogen pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs), and 2,2′,4,4′-tetrabrominated diphenyl ether (BDE #47) in a marine benthic fish, Pseudopleuronectes yokohamae. The respiratory uptake efficiencies (EW) of the chemicals, of which there have been no reports for the majority of persistent organic pollutants (POPs), were obtained by measuring the respiratory uptake rate constants (k1) and the oxygen consumption rates of fish. Fish were exposed to water in which these chemicals were dissolved at environmentally relevant concentrations for 28 d, followed by 168 d of depuration in clean seawater. The k1 and EW values for 99 compounds were obtained, and they ranged from 2000 to 42 000 L kg-lipid−1 d−1 and from 0.060 to 1.3, respectively. The EW values of the chemicals, except for PAHs, tended to increase with increasing values of the log octanol–water partition coefficients (KOW) of the chemicals up to a log KOW of 5. For log KOW in the range 3–5, the EW values in this study were much lower than those in a published study (about one-third). As a result of analysis by a two-phase resistance model, the resistance of transport rates to the lipid phase in this study was lower than was the case in the published study. These findings indicate that the EW predicted by the published study for log KOW in the range 3–5 may differ among fish species and water temperature, and further study is needed.  相似文献   
60.
Sedimentation and remobilization processes of radiocesium were investigated from time-series observations at nine stations in the coastal area of Ibaraki, 70–110 km south of the Fukushima Dai-ichi Nuclear Power Plant (1FNPP). Sediment samples were collected four times between June 2011 and January 2012, and concentrations of radiocesium as well as sediment properties such as grain size and elemental compositions were analyzed. Cumulative inventory of 137Cs in sediment (0–10 cm) ranged between 4?×?103 and 3?×?104 Bq/m2 as of January 2012. This amount was generally higher at stations nearer 1FNPP and has remained at the same level since August 2011. From these results, it can be inferred that dissolved radiocesium advected southward from the region adjacent to the 1FNPP and was deposited to the sediment of the study area in the early stage after the accident. The incorporation of radiocesium into sediments was almost irreversible, and higher concentrations of 137Cs were obtained from the finer-grained fraction of sediments. In the northern offshore stations, resuspension of the fine-grained sediments formed a high-turbidity layer 10–20 m above the seabed. These results indicate that radiocesium-enriched fine particles were transported from the coast to offshore regions through the bottom high-turbidity layer.  相似文献   
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