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1.
Samal Kaumbekova Mehdi Amouei Torkmahalleh Naoya Sakaguchi Masakazu Umezawa Dhawal Shah 《Frontiers of Environmental Science & Engineering》2023,17(2):15
2.
Yuuki Miyata Kensuke Miyazaki Masahiro Miura Yasutaka Shimotori Masakazu Aoyama Hisayuki Nakatani 《Journal of Polymers and the Environment》2013,21(1):115-121
A novel solventless delignification of a defatted Picea glehnii wood flour sample was performed using a TiO2/polyethylene oxide (PEO) photocatalyst system. A cell wall structure of the wood flour was directly observed, showing that its lignin fraction was removed by the photodegradation. The total lignin amount was slightly decreased as compared with that of the pristine sample, and the vanillin formation was confirmed by the 1H-NMR measurement. The TiO2 worked as a radical initiator, and simultaneously acid and aldehyde compounds produced by the PEO photolysis did as an accelerator for the solventless delignification. Although the photocatalyst system showed high delignification activity even for a low molecular lignin model, the delignification of the wood flour sample was confined to the surface. It was found that the suppressed delignification behavior was due to crosslinked structure of lignin. 相似文献
3.
The actual standard in vitro fertilization (IVF) protocol recommends an overnight gamete co-incubation. All of the culture media used for human IVF are supplemented with serum or albumin. In the present study, we determined the concentrations of perfluorinated chemicals (PFCs) in IVF media (IVFM) and related samples by liquid chromatography with tandem mass spectrometry (LC/MS/MS). The results indicated that the concentrations of PFOS and PFOA in the protein source were higher than those in the IVFM samples. Compared with human plasma concentrations of PFCs, PFCs in all of the IVFM samples, such as PFBS, PFHxS and PFOA, were either not detected or present at only trace levels, even when protein source was added. LC/MS/MS could be used to determine PFCs in IVFM samples in future studies of the effects of PFC exposure on intrauterine insemination. 相似文献
4.
A sample of commercial BADGE was fractioned by HPLC and eight impurities including novel propyl derivatives (2), (5) and (6) were identified by NMR spectrometry, FAB-MS and GC-MS. The estrogenicity, both agonist and antagonist, of fractions containing these impurities was measured with a yeast two-hybrid assay incorporating the human (hER alpha) and a competitive binding assay for hER alpha (ELISA). In the yeast two-hybrid assay, estrogenic antagonist activity was found in two fractions, while estrogenic agonist activity was not found in any. In the ELISA method, the binding affinity to hER alpha was found in three fractions. It is probable that a comprehensive assessment of the estrogenic properties of commercial BADGE, and their implications for human health, will require examination of all its components as described here. 相似文献
5.
6.
Behavior and prediction of photochemical degradation of chlorinated polycyclic aromatic hydrocarbons in cyclohexane 总被引:3,自引:0,他引:3
The photochemical degradation of 11 chlorinated polycyclic aromatic hydrocarbons (ClPAHs) and the corresponding 5 parent PAHs was examined to simulate the compound’s fate on aerosol surfaces. All the ClPAHs and PAHs decayed according to the first-order reaction rate kinetics. The photolysis rates of ClPAHs varied greatly according to the skeleton of PAHs; the rates of chlorophenanthrenes (ClPhes) and 1-chloropyrene were higher than those of corresponding parent PAHs, whereas chlorofluoranthenes, 7-chlorobenz[a]anthracene and 6-chlorobenzo[a]pyrene were more stable under irradiation compared to respective parent PAH. Considering the photoproducts of ClPhes detected, the oxidation could occur immediately at positions of the highest frontier electron density. Finally, the quantitative structure-property relationship models were developed for direct photolysis half-lives and average quantum yields of the ClPAHs and parent PAHs, in which the significant factors affecting photolysis were ELUMO+1, total energy and surface area, and ELUMO, ELUMO − EHOMO and total energy, respectively. 相似文献
7.
Formation of dioxins (PCDDs/PCDFs) by dioxin-free fly ash as a catalyst and relation with several chlorine-sources 总被引:2,自引:0,他引:2
Simplified thermal formation experiments have been conducted using dioxin-free fly ash as a catalyst with many kinds of combustible samples such as newspaper, kerosene, paraffin, PE (polyethylene), PP (polypropylene) and PVC. Chlorine sources were PVC, NaCl and HCl. The combustion of samples containing chlorine in the absence of dioxin-free fly ash produced dioxins at a low level although HCl was present in the gas stream. On the other hand, the combustion of samples without chlorine with dioxin-free fly ash increased dioxins formation to a level around 10 times higher than that upon heating dioxin-free fly ash alone. This result is considered to be due to the presence of metal chloride in the fly ash and hydrocarbons in the gas stream. The combustion of samples containing either an organic or inorganic chlorine source or using a HCl stream with dioxin-free fly ash increased dioxin level dramatically. 相似文献
8.
Symbiont-induced male-killing phenotypes have been found in a variety of insects. Conventionally, these phenotypes have been
divided into two categories according to the timing of action: early male killing at embryonic stages and late male killing
at late larval stages. In Drosophila species, endosymbiotic bacteria of the genus Spiroplasma have been known to cause early male killing. Here, we report that a spiroplasma strain normally causing early male killing
also induces late male killing depending on the maternal host age: male-specific mortality of larvae and pupae was more frequently
observed in the offspring of young females. As the lowest spiroplasma density and occasional male production were also associated
with newly emerged females, we proposed the density-dependent hypothesis for the expression of early and late male-killing
phenotypes. Our finding suggested that (1) early and late male-killing phenotypes can be caused by the same symbiont and probably
by the same mechanism; (2) late male killing may occur as an attenuated expression of early male killing; (3) expression of
early and late male-killing phenotypes may be dependent on the symbiont density, and thus, could potentially be affected by
the host immunity and regulation; and (4) early male killing and late male killing could be alternative strategies adopted
by microbial reproductive manipulators. 相似文献
9.
Katase T Okuda K Kim YS Eun H Takada H Uchiyama T Saito H Makino M Fujimoto Y 《Chemosphere》2008,70(11):1961-1972
Thirteen isomers of branched para-nonylphenols (para-NP) in three technical mixtures were isomer-specifically determined using their synthesized standards by SIM of structurally specific ions, m/z 135, 149 or 163 with GC–MS. Of the 13 isomers, four isomers, 4-(2,4-dimethylheptan-4-yl)phenol, 4-(4-methyloctan-4-yl)phenol, 4-(3-ethyl-2-methylhexan-2-yl)phenol (3E22NP) and 4-(2,3-dimethylheptan-2-yl)phenol synthesized for their determinations were first used as standard substances. The 13 isomers in the technical mixtures individually occurred at mass percent portion of more than 2%. The total mass percent portions in the mixtures from Tokyo Chemical Industry (TCI), Aldrich, and Fluka covered with 89 ± 2%, 75 ± 4% and 77 ± 2%, respectively. The abundance of 4-(3,6-dimethylheptan-3-yl)phenol in the three mixtures was the largest with 11.1 ± 2% to 9.9 ± 0.3%, while that of 4-(2-methyloctan-2-yl)phenol was the smallest with 2.9 ± 0.3% to 3.0 ± 0.2%. Additionally, structures of four new isomers of more than 1% portion present in a technical mixture were elucidated as two pairs of diastereomeric isomers: two types of 4-(3,4-dimethylheptan-4-yl)phenol (344NP) and those of 4-(3,4-dimethylheptan-3-yl)phenol (343NP). By estrogenic assay of 13 isomers with yeast estrogen screen system, the activity of 3E22NP was the highest, while that of 4-(3-methyloctan-3-yl)phenol was the least. Their relative activities to that of 3E22NP were individually calculated. Estrogenic equivalent concentrations of the three technical mixtures were predictively evaluated. The ratio of the EEC to the conventional concentration, total mass percent portions of the 13 isomers in technical mixtures were 0.208 for TCI, 0.206 for Aldrich and 0.205 for Fluka. The predicted estrogenic activity of measured concentration of para-NP in technical mixtures was approximately 5-fold greater than the measured estrogen agonist activity. 相似文献
10.
Two sets of new diastereomeric 4-nonylphenol (NP) isomers [4-(3,4-dimethylheptan-4-yl)phenol (344NP, NP-J, L) and 4-(3,4-dimethylheptan-3-yl)phenol (343NP, NP-K, P)] were separated from a commercial NP mixture. The mixture of these diastereomers was synthesized at the same time by a single Friedel-Crafts reaction of 3,4-dimethyl-4-heptanol and phenol, and the mixture was separated into individual NPs by HPLC equipped with Hypercarb column. For the first time, in this study the stereostructure-estrogenic activity relationship of NP diastereomers was investigated. The NP isomers (NP-L and NP-P) having the beta-methyl group over the benzene ring were found to be 2-4 times more estrogenic than their diastereomers (NP-J and NP-K). In the case of the other set of diastereomer [4-(3,5-dimethylheptan-3-yl)phenol, (353NP, NP-E, G)] containing gamma-methyl group in the molecule, the gamma-methyl proton signal (delta 0.49) in the more estrogenic isomer (NP-G) also appeared in a higher field than the corresponding methyl signal (delta 0.76) of the less estrogenic isomer (NP-E). 相似文献