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41.
The sulfur butterfly, Colias erate, utilizes various legumes as host plants. We examined the chemical constituents of its primary host plant, Trifolium repens (white clover), to identify phytochemicals inducing oviposition by C. erate females. Since one of the four aqueous subfractions prepared from a methanolic extract of the plant has previously been shown to be the most responsible for the oviposition-stimulatory activity exerted by the plant, chemical analyses were conducted of the fraction concerned. Activity-directed fractionation of the subfraction by ion-exchange chromatography revealed that the key substance(s) resided in the neutral fraction. Preparative TLC of the neutral fraction and subsequent spectral analyses identified d-(+)-pinitol, glycerin, methyl β-d-glucoside, and myo-inositol as characteristic components together with ubiquitous sugars (e.g., sucrose and glucose). Of these, only pinitol singly evoked significant oviposition responses at concentrations over 0.05%. In dual-choice bioassays, however, females laid significantly more eggs on pinitol solutions admixed with glycerin or methyl β-d-glucoside than on pinitol alone. Two cyanoglucosides, linamarin, and lotaustralin, occurring in the other aqueous subfractions, also synergistically increased the oviposition response in combination with pinitol. The results clearly indicated that pinitol is a crucial oviposition stimulant involved in host recognition, while glycerin, methyl β-d-glucoside, linamarin, and lotaustralin function as synergists. We further examined the oviposition responses of C. erate females to aqueous fractions, along with their chemical compositions, that had been prepared from five other host plants and a non-host plant, Aristolochia debilis (Aristolochiaceae), on which oviposition occasionally took place in an outdoor cage during the experiments. The plant species accepted by ovipositing females were all found to contain pinitol in amounts enough to induce egg laying by the butterfly, thus leading to the conclusion that pinitol serves as the essential mediator in recognizing and accepting potential host plants.  相似文献   
42.
The objective of this study was to investigate the properties of poly(vinyl alcohol)/chitosan nanocomposite films reinforced with different concentration of amorphous LCNFs. The properties analyzed were morphological, physical, chemical, thermal, biological, and mechanical characteristics. Oil palm empty fruit bunch LCNFs obtained from multi-mechanical stages were more dominated by amorphous region than crystalline part. Varied film thickness, swelling degree, and transparency of PVA/chitosan nanocomposite films reinforced with amorphous part were produced. Aggregated LCNFs, which reinforced PVA/chitosan polymer blends, resulted in irregular, rough, and uneven external surfaces as well as protrusions. Based on XRD analysis, there were two or three imperative peaks that indicated the presence of crystalline states. The increase in LCNFs concentration above 0.5% to PVA/chitosan polymer blends led to the decrease in crystallinity index of the films. A noticeable alteration of FTIR spectra, which included wavenumber and intensity, was obviously observed along with the inclusion of amorphous LCNFs. That indicated that a good miscibility between amorphous LCNFs and PVA/chitosan polymer blend generated chemical interaction of those polymers during physical blending. Reinforcement of PVA/chitosan polymer blends with amorphous LCNFs influenced the changes of Tg (glass transition temperature), Tm (melting point temperature), and Tmax (maximum degradation temperature). Three thermal phases of PVA/chitosan/LCNFs nanocomposite films were also observed, including absorbed moisture evaporation, PVA and chitosan polymer backbone structural degradation and LCNFs pyrolysis, and by-products degradation of these polymers. The addition of LCNFs 0.5% had the highest tensile strength and the addition of LCNFs above 0.5% decreased the strength. The incorporation of OPEFB LCNFs did not show anti-microbial and anti-fungal properties of the films. The addition of amorphous LCNFs 0.5% into PVA/chitosan polymer blends resulted in regular and smooth external surfaces, enhanced tensile strength, increased crystallinity index, and enhanced thermal stability of the films.  相似文献   
43.
Food and Environmental Virology - Highly sensitive detection of pathogens is effective for screening meat during quarantine inspection and export. The “micro-amount of virion enrichment...  相似文献   
44.
Results of surveys on Polychlorinated biphenyls (PCB) and organochlorine insecticides (HCH and DDT) in fish and shellfish from Lake Biwa were summarized from 1987 to 1996. In 1975, fish and shellfish in Lake Biwa were highly contaminated with PCB, HCH and DDT but recently in 1992–1996 the concentrations of these chemicals were very low and nearly constant. In the composition of HCH isomers, β‐HCH was dominant in all kinds of fish and shellfish. In the composition of DDT and DDT metabolites, pp'‐DDE was similarly dominant in all kinds of fish and shellfish. Further, the data in Lake Biwa were compared with those in Lake Michigan and Lake Baikal.  相似文献   
45.
An accurate estimation of a plant's age is required for the prediction of yield and management practices. This study demonstrates the relationship between backscattering properties (σ°) of Phased Array type L-band Synthetic Aperture Radar (PALSAR) dual polarimetric data with cashew plants' biophysical parameters (height, age, crown diameter, diameter at breast height, basal area, tree density, and biomass) in Cambodia. PALSAR σ° has shown a positive correlation with the biophysical parameters of cashew plants. The value of σ° increases with the age of cashew plants. At a young stage, the cashew plants show a higher rate of an increase in σ° compared to that at the mature stage. The σ° horizontal polarization transmitted and vertical received (HV) shows higher sensitivity to the plant's growth than σ° horizontal polarization transmitted and received (HH). High backscattering and low variations were observed at mature stage (8–12 years) of cashew plantation. Saturation in backscattering has shown from the age of about 13 years. The validation results indicate strong coefficient of determination (R 2?=?0.86 and 0.88) for PALSAR-predicted age and biomass of cashew plants with root mean square error?=?1.8 years and 16.3 t/ha for age and biomass, respectively. The correlations of σ° (HH) with biophysical parameters observed in the dry season were better than those of the rainy season because soil moisture interferes with backscattering in the rainy season. Biomass accumulation rate of cashew plants has been predicted that would be useful for selection of plants species to enhance carbon sequestration. This study provides an insight to use PALSAR for the monitoring of growth stages of plants at the regional level.  相似文献   
46.
Phthalate esters (PEs) have been suspected to be environmental endocrine disruptors and the detailed mechanism remains unclear. The activities of these chemicals can be enhanced through chemical modification under the environmental conditions. We demonstrate that PEs acquire unequivocal estrogenic activity by light exposure. Through UV exposure of an aqueous PE solution, one active photoproduct, identified as 4-hydroxyPE (PE-4OH) based on its characteristic UV and mass spectra, was detected in an estrogen receptor alpha-dependent transactivation assay. PE-4OH was effectively generated by UV 290 nm. The PE-4OH production accompanied H2O2 generation in a UV dose-dependent manner. Both PE and UV irradiation were indispensable in the generation of H2O2. Addition of H2O2 to the PE solution increased PE-4OH production under UV irradiation. The PE-4OH production was also observed in the PE reaction with the Fenton reagent generating hydroxyl radical without UV irradiation. The proposed mechanism for PE-4OH production based on these results is such that by PE-mediated photosensitization H2O2 is generated from O2 and H+ and decomposed to hydroxyl radical, thus oxidizing the PE benzene ring. The PEs-4OH are remarkably active estrogenic products of PEs and would be involved in ER-mediated endocrine disruption.  相似文献   
47.
To assess the capacity of the natural environment for degrading PHB/V, the film-MPN method proposed previously was modified to estimate the numbers of PHB/V degrading microorganisms (degraders) in various environments. The First-Order Reaction (FOR) model was used to determine the appropriate incubation period for the method. Numbers of aerobic PHB/V degraders were estimated in garden soil, paddy field soil, farm soil, river bank soil, infertile garden soil, river water, activated sludge, and seawater by the film-MPN method. Results were compared with those estimated by the clear-zone technique and showed that the film-MPN method was suitable for estimating the numbers of PHB/V degraders in the environments tested. On the other hand, biodegradability of injection molded PHB/V samples was investigated in several kinds of environments. The changes of weight were studied and results showed that biodegradability of PHB/V related to the numbers of PHB/V degraders in similar ecosystem in different regions. In different environments the biodegradability of PHB/V not only related to the number of PHB/V degraders, but also depended on whether there were conditions for the PHB/V degraders to grow and proliferate easily in the environment.  相似文献   
48.
To control the emission of halides into the environment, an experiment on the nonthermal plasma decomposition of the halides CF4, CHF3, C2HCl3, and CHClF2 was conducted in a wire-in-tube corona reactor. It was found that the decomposition of C2HCl3 and CHClF2 was easy compared with the decomposition of CF4 and CHF3. With the addition of H2 in N2 gas, the decomposition ratio of CF4, C2HCl3, and CHClF2 increased. In contrast, the decomposition ratio of CHF3 in a hydrogen-rich atmosphere was lower than that in an N2 atmosphere. It was demonstrated that the yields of HF and/or HCl formed during halide decomposition clearly increased in the presence of H2 in N2 gas. Furthermore, in order to prevent the production of unwanted products from halide decomposition, a combination of plasma decomposition and in situ alkaline absorption was devised by coating a layer of Ca(OH)2 onto the surface of the grounding electrode. It was demonstrated that the Ca(OH)2 sorbent played an effective role as a scavenger, participating in halide decomposition by capturing reaction products such as HCl and HF, therefore resulting in increased halide decomposition.  相似文献   
49.
From the point of view of a sustainable and environment-friendly society based on the recycling of material resources, it is preferable to utilize waste gypsum as a substitute for lime, which is currently produced by the calcination of limestone. In the present work, the reductive decomposition of CaSO4 was investigated under an atmosphere of CO: 2 vol%, CO2: 30 vol%, with N2 as a carrier gas without and with the addition of SiO2, Al2O3, or Fe2O3. It was found that the decomposition temperature of CaSO4 was significantly reduced from 1673 K to 1223 K when only 5 wt% Fe2O3 was added to CaSO4. In the case of the addition of SiO2 or Al2O3 to CaSO4, the decomposition temperature was reduced from 1673 K to 1623 K. This was due to the formation of composite oxides (calcium ferrite, calcium silicate, or calcium aluminate) during the reaction of CaSO4 with the additives at a lower temperature. In addition, the formation of unfavorable product CaS was inhibited in the presence of 5 wt% Fe2O3, and this inhibition effect further increased as the addition of Fe2O3 was increased. In contrast, no significant effect on the inhibition of CaS formation was observed on the addition of SiO2 or Al2O3.  相似文献   
50.
高压喷射注浆加固地基RJP工法及北京现场试验   总被引:1,自引:0,他引:1  
为满足土木工程建设对大直径旋喷桩和超深基础防漏止水的需要,1988年RJP(RodinJetPile)工法应运而生。其旋喷桩直径达240~320厘米,固结体质量优良,工艺可靠,成本较低。1996年5月在旋喷发明人、本工法专利权拥有者中西涉博士的指导下,中日数公司在北京探矿机械厂内联合进行了RJP工法现场试验。旋喷桩直径达3米,团结强度良好,施工工艺简单。试验结果表明,在拥有三重管旋喷设备和经验的中国有良好的推广应用价值和发展前景。  相似文献   
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