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1.
Takeshi Sasaki Atsushi Iizuka Masayuki Watanabe Teruhisa Hongo Akihiro Yamasaki 《Waste management (New York, N.Y.)》2014,34(10):1829-1835
Solid adsorbent materials, prepared from waste cement powder and concrete sludge were assessed for removal of arsenic in the form of arsenic (As(V)) from water. All the materials exhibited arsenic removal capacity when added to distilled water containing 10–700 mg/L arsenic. The arsenic removal isotherms were expressed by the Langmuir type equations, and the highest removal capacity was observed for the adsorbent prepared from concrete sludge with heat treatment at 105 °C, the maximum removal capacity being 175 mg-As(V)/g. Based on changes in arsenic and calcium ion concentrations, and solution pH, the removal mechanism for arsenic was considered to involve the precipitation of calcium arsenate, Ca3(AsO4)2. The enhanced removal of arsenic for the adsorbent prepared from concrete sludge with heat treatment was thought to reflect ion exchange by ettringite. The prepared adsorbents, derived from waste cement and concrete using simple procedures, may offer a cost effective approach for arsenic removal and clean-up of contaminated waters, especially in developing countries. 相似文献
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One of the major consequences of global warming is a rise in sea surface temperature which may affect the survival of marine
organisms including phytoplankton. Here, we provide experimental evidence for heat-induced cell death in a symbiotic microalga.
Shifting Symbiodinium microadriaticum from 27 to 32°C resulted in an increase in mortality, an increase in caspase 3-like activity, and an increase in nitric oxide
(NO) production. The caspase-like activity was strongly correlated with the production of NO in thermally challenged microalgae.
For this experiment, the application of Ac-DEVD-CHO, a mammalian caspase 3-specific inhibitor, partly prevented (by 65%) the
increase in caspase-like activity. To verify the relationship between NO and the caspase-like activity, S. microadriaticum were subsequently incubated with 1.0 mM of the following chemical NO donors: sodium nitroprusside (SNP), S-nitrosoglutathione (GSNO), S-nitroso-N-acetylpenicillamine (SNAP) and 3,3bis(Aminoethyl)-1-hydroxy-2-oxo-1-triazene (NOC-18). The supplementation of both SNP and
NOC-18 caused a significant increase in caspase-like activity compared to the control treatment. Pre-treatment of the microalgae
with the inhibitor Ac-DEVD-CHO before the supplementation of the different NO donors completely prevented the increase in
caspase-like activity. These results suggest that NO could play a role in the induction of cell death in heat-stressed S. microadriaticum by mediating an increase in caspase-like activity. 相似文献
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Mamoru Nishioka Nakamichi Yamasaki Hiroshi Amano Masanori Higuchi 《Waste management (New York, N.Y.)》1992,12(4)
Tritium is generally disposed of as an oxide form, and immobilization of tritium oxide with Portland cement is the most popular disposal method. However, the cement solidified body is rather leachable for tritium and is poor in some physical properties. A silicate powder, such as borosilicate glass powder, forms a synthetic rock by the hydrothermal hot-pressing (HHP) technique, making it a technique for immobilization of tritium oxide. Tritium oxide with borosilicate glass powder was solidified by the HHP technique. Leachability of tritium from the produced solidified bodies and the behavior of fixed tritium oxide during the heating were studied and discussed. The amount of tritium oxide fixed by the present procedure was almost the same as that fixed by the ordinary cement solidifying procedure. The diffusivity of tritium from the body by this procedure was much lower than that from the cement body and the compressive strength of the body was higher than that of the cement body. 相似文献
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Isoprene emission from tropical trees in Okinawa Island, Japan 总被引:1,自引:0,他引:1
Tambunan P Baba S Kuniyoshi A Iwasaki H Nakamura T Yamasaki H Oku H 《Chemosphere》2006,65(11):2138-2144
This study surveyed isoprene emission from 42 indigenous and exotic tropical trees in subtropic Okinawa, Japan. Of the 42 trees studied, 4 emitted isoprene at a rate in excess of 20 μg g−1 h−1, and 28 showed the rates of 1–10 μg g−1 h−1. The remainder emitted less than 1 μg g−1 h−1. The majority of trees in this study may therefore fall within the lower emitting species. However, species in Moraceae that is indigenous in Okinawa emitted isoprene at relatively higher rates with an average of 14.2 μg g−1 h−1. The highest emission rate of 107.1 μg g−1 h−1 for Ficus virgata yielded the area basis rate of 47.4 nmol m−2 s−1, which is almost equivalent to the rate of high emitting species. Furthermore, a linear relationship between light intensity and isoprene emission was noted with Ficus virgata up to 1700 μmol m−2 s−1. These findings may show the potential importance of subtropical areas as sources of isoprene to the atmosphere. 相似文献
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Yasuhiro Yamasaki Sou Nagasoe Tadashi Matsubara Tomoyuki Shikata Yohei Shimasaki Yuji Oshima Tsuneo Honjo 《Marine Biology》2007,152(1):157-163
We investigated the growth interaction between Cochlodinium polykrikoides and Akashiwo sanguinea using bi-algal cultures. When cultured together, morphologically abnormal cells of A. sanguinea appeared and the growth of A. sanguinea notably decreased. When C. polykrikoides and A. sanguinea were cultured separately in inner and outer wells separated by a membrane with a pore size of 3 μm, neither species showed
suppressed growth and no morphologically abnormal cells of A. sanguinea were observed. Furthermore, filtrates from C. polykrikoides cultures did not affect the cell morphology or the growth of A. sanguinea. When the abnormal cells of A. sanguinea were transferred from bi-algal cultures into fresh medium and cultured as a mono-algal culture, cells recovered their normal
morphology and multiplied. Therefore, the growth inhibition and formation of morphologically abnormal cells of A. sanguinea would be induced by constant cell contact with C. polykrikoides. 相似文献
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Ken Sasaki Kazuhisa Yamasaki Koji Tsuchida Takashi Nagao 《Die Naturwissenschaften》2009,96(5):625-629
In social insects, biogenic amines are thought to play regulatory roles in the transition between reproductive states in females.
To determine the effect of dopamine on the reproductive development of workers in primitively eusocial societies, isolated
workers of the paper wasp Polistes chinensis were supplied with oral dopamine. Ovarian development was accelerated in dopamine-fed workers as compared to control workers
of the same age fed only sucrose solution. Oral dopamine increased brain levels of dopamine and its metabolite (N-acetyldopamine). Brain levels of tyramine or octopamine were also increased by dopamine application in one of two colonies;
levels of the tyramine metabolite N-acetyltyramine were unchanged. These results indicate that dopamine plays a gonadotropic role in isolated workers in the
primitively eusocial wasp, similar to the gonadotropic role previously reported for juvenile hormone. This is the first study
to report effects of dopamine on ovarian development in workers of the paper wasp. 相似文献
10.
Shinohara N Kumagai K Yamamoto N Yanagisawa Y Fujii M Yamasaki A 《Journal of the Air & Waste Management Association (1995)》2004,54(4):419-424
A carbonyl sampler originally designed for the active sampling method (Sep-Pak XPoSure) was used for long-term passive sampling, and its applicability as a passive sampler was examined through field experiments. The uptake rates of passive sampling were determined experimentally from collocated passive and active samplings for various sampling periods. The obtained uptake rates of formaldehyde, acetaldehyde, and acetone were 1.48, 1.23, and 1.08 mL/min, respectively. These uptake rates were consistent for a wide range of the sampling term (12 hr-2 weeks). Uptake rates of each carbonyl were proportional to the diffusion coefficients of each. Therefore, the ratios of diffusion coefficients were used to calculate the uptake rates of carbonyls for which the rates were not determined experimentally. Lower limits of determination were 2.16-17.5 microg/m3 for 2-week sampling. It was confirmed that 2-week monitoring of carbonyl concentrations up to 118-229 microg/m3 was possible. Relative standard deviations of the passive method generated from the repeatability test were 2-12.3% error for five samplings, and the recovery efficiencies were larger than 90%. Thus, the passive sampler was found to be highly suitable for long-term monitoring of carbonyl compounds. 相似文献