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A soft actuator mimicking natural muscles (artificial muscle) has been developed using a flexible conducting polymer of polypyrrole films, which were driven by electrical stimulus in a saline solution. The work characteristics were studied under various load stresses and found to behave like natural muscles. The artificial muscles shrunk and stiffened by the positive electrical stimulus by 2-3% at the maximum force of 5 MPa, and relaxed by application of negative voltages. At larger load stresses, the artificial muscle shrunk slowly as natural muscles do. The driving current also lasted longer at larger loads, indicating that the muscle sensed the magnitude of the load stress. During contraction of the muscle, the conversion efficiency from the electrical input and mechanical output energies was estimated to be around 0.06%. The maximum volumetric work was approximately estimated to be 100 kJ m(-3). These figures are unexpectedly small compared with those of natural muscles. 相似文献
64.
MpkA-Dependent and -independent cell wall integrity signaling in Aspergillus nidulans 总被引:1,自引:0,他引:1 下载免费PDF全文
Fujioka T Mizutani O Furukawa K Sato N Yoshimi A Yamagata Y Nakajima T Abe K 《Eukaryotic cell》2007,6(8):1497-1510
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Exercise-induced lipid peroxidation and leakage of enzymes before and after vitamin E supplementation 总被引:11,自引:0,他引:11
1. The purpose of this study was to investigate the effects of vitamin E on serum levels of malondialdehyde following the acute exhaustive exercise in human, and to determine whether the magnitude of leakage of enzyme would be affected by vitamin E supplementation. 2. Increase of malondialdehyde after exercise before vitamin E supplementation was slight (but statistically significant), however after supplementation with vitamin E, malondialdehyde level after exercise was significantly decreased. 3. Leakage of enzyme was significantly increased after exercise before vitamin E supplementation, but it was lower following exercise after vitamin E supplementation. 4. Lipid peroxidation following a bout of acute heavy exercise can be inhibited by vitamin E supplementation. 相似文献
67.
A mixture of steamed soybean and boiled rice with seeded Aspergillus oryzae was naturally fermented without addition of yeasts or Lactobacilli, and kept matured for 12 months at room temperature. Chemical analysis of this rice-koji miso sample for lipid changes during maturation showed that triacylglycerol was gradually decomposed into free fatty acid, with distinct formation of fatty acid ethyl ester which, six months after the start of fermentation, came to account for 35.0% of total lipid. The ester was constituted primarily with linoleic acid (ca. 50%) and oleic acid (ca. 20%), no appreciable change in this proportion being observed during maturation. Also, the proportion was unique in that this did not reflect the fatty acid composition in a mixture of the two materials. It is possible to monitor the maturation of the rice-koji miso by following up the increase with time in fatty acid ethyl ester. 相似文献
68.
Kentaro?HayashiEmail author Masanori?Okazaki Norihiro?Itsubo Atsushi?Inaba 《The International Journal of Life Cycle Assessment》2004,9(1):13-22
Background Acidification is one of the important impact categories for life cycle impact assessment. Although its characterization has
progressed during this decade through the employment of midpoint approaches, only limited studies of endpoint approaches have
been performed. Objective. This study aimed at developing damage function of acidification for terrestrial ecosystems in Japan.
Damage function expresses a quantitative relationship between the inventory and endpoint damage.
Methods The geographical boundary was limited in Japan both for emission and impact. In this study, sulfur dioxide (SO2), nitrogen monoxide (NO), nitrogen dioxide (NO2) (NO and NO2 collectively mean NOx), hydrogen chloride (HC1), and ammonia (NH3) were considered as major causative substances of acidification. Net primary production (NPP) of existing vegetation was
adopted as an impact indicator of terrestrial ecosystems. The aluminum toxicity was adopted as the major factor of effect
on terrestrial ecosystems due to acidification. The leachate concentration of monomeric inorganic aluminum ions was selected
to express the plant toxicity of aluminum.
Results and Discussion The results of damage function gave utilizable factors both for a midpoint approach and an endpoint approach; Atmospheric
Deposition Factor (ADF) and Damage Factor (DF) applicable to the former and the latter, respectively. The ADF indicates an
increase of H+ deposition per unit area to an additional emission of causative sustance. The additional emission corresponds to some alternatives
in industry, not the baseline emission. The DF indicates the total NPP damage in all of Japan due to the additional emission
of causative substances. The derived NPP damage is on the order of one millionth of the NPP itself. HC1 and NH3 showed larger
ADFs and DFs than that of SO2 and NOx. The reason was ascribed to the relatively large source-receptor relationships (SRR) of HC1 and NH3. However, since the method applied to determine the SRR of HC1 and NH3 has larger uncertainties than that of SO2 and NOx, attention is needed to handle the difference.
Conclusion The damage function easily defines the concrete NPP damage due to an additional emission. The impact indica tor, NPP, also
has an advantage in its mass unit that is directly summable through the entire impact categories. Expansion of endpoints,
such as in aquatic ecosystems, material degradation, human health, and biodiversity aspects of terrestrial ecosystems, is
an important subject for future work. Further, uncertain analyses for major parameters will provide helpful information on
the reliability of damage function. 相似文献
69.
The primary amino groups of biomolecules such as aminophospholipids, as well as proteins, are the potential targets of covalent modifications by lipid peroxidation products; however, little attention has been paid to the modification of aminophospholipids such as phosphatidylethanolamine (PE). The purpose of this study is to characterize the formation of a novel modified phospholipid, N-(hexanoyl)phosphatidylethanolamine (HEPE), in the reaction of PE with lipid hydroperoxides using mass spectrometric analyses. Upon reaction of egg PE with 13-hydroperoxyoctadecadienoic acid or other oxidized polyunsaturated fatty acids followed by phospholipase D-mediated hydrolysis, the formation of N-(hexanoyl)ethanolamine (HEEA), a head group of HEPE, was confirmed by isotope dilution liquid chromatography/tandem mass spectrometry. Moreover, increasing HEEA was detected in the hydrolysates of oxidized erythrocyte ghosts and low-density lipoprotein with their increasing lipid peroxidation levels. Collectively, these results suggest that the N-hexanoylated product of phospholipid, HEPE, can be generated during lipid peroxidation and may serve as one mechanism for the covalent modification of aminophospholipids in vivo. 相似文献
70.
Toc75 is postulated to form the protein translocation channel in the chloroplastic outer envelope membrane. Proteins homologous to Toc75 are present in a wide range of organisms, with the closest homologs occurring in cyanobacteria. Therefore, an endosymbiotic origin of Toc75 has been postulated. Recently, a gene encoding a paralog to Toc75 was identified in Arabidopsis and its product was named atToc75-V. In the present study, we characterized this new Toc75 paralog, and investigated extensively the relationships among Toc75 homologs from higher plants and bacteria in order to gain insights into the evolutionary origin of the chloroplastic protein translocation channel. First, we found that the native molecular weight of atToc75-V is 80 kDa and renamed it (AtOEP80) Arabidopsis thalianaouter envelope protein of 80 kDa. Second, we found that AtOEP80 and Toc75 utilize different mechanisms for their targeting to the chloroplastic envelope. Toc75 is directed with a cleavable bipartite transit peptide partly via the general import pathway, whereas AtOEP80 contains the targeting information within its mature sequence, and its targeting is independent of the general pathway. Third, we undertook phylogenetic analyses of Toc75 homologs from various organisms, and found that Toc75 and OEP80 represent two independent gene families that are most likely derived from cyanobacterial sequences. Our results suggest that Toc75 and OEP80 diverged early in the evolution of plastids from their common ancestor with modern cyanobacteria. 相似文献