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21.
The half wave potential of reduction of Sb5+ in 16Na2O x 10CaO x 74SiO2 glass melts was examined by differential pulse voltammetry up to 1873 K. The half wave potential shifted to the positive direction with an increase in temperature. The results indicate that the equilibrium of Sb5+/Sb3+ shifted to negative direction with an increase in temperature. The half wave potential shifted to positive direction (48 mV at 1473 K) when the atmosphere over the melts changed from pure oxygen gas to air, in agreement with the theoretical prediction. The reversibility of Pt:O2 reference electrode is confirmed. 相似文献
22.
T. Matsuo T. Maekawa A. Inaba O. Yamamuro M. Ohama M. Ichikawa T. Tsuchida 《Journal of Molecular Structure》2006,790(1-3):129
The heat capacities of HCrO2 and DCrO2 have been measured at temperatures between 5 and 360 K. A lambda anomaly occurred at 320 K for DCrO2 but not for HCrO2. Infrared spectra were recorded at temperatures between 5 and 405 K. The spectrum of DCrO2 changed at 320 K with respect to the peak wave-number and splitting of some of the vibrations, while those of HCrO2 depended smoothly on temperature. These experimental results are discussed in terms of a deuteration-induced phase transition. 相似文献
23.
The irradiation of N-(4-substituted benzoyl)-α-dehydroarylalanine alkyl esters (1) in methanol containing triethylamine (TEA) was found to quantitatively give cis- and trans-4,5-dihydrooxazole derivatives (2), which were described as being formed via electron transfer from TEA to the excited-state (E)-1 followed by kinetically-controlled cyclization of the (E)-1-derived anion radical. A product composition analysis showed that the cis-2/trans-2 composition ratio is greatly varied depending on the stereoelectronic properties of the substituents, the polarity of protic solvents and the concentration of TEA. 相似文献
24.
The electronic state in layered cobalt oxides with a hexagonal structure is examined. We find that the electronic structure reflects the nature of the Kagomé lattice hidden in the CoO2 layer which consists of stacked triangular lattices of oxygen ions and of cobalt ions. A fundamental model for the electron system is proposed, and the mechanism of the unique transport and magnetic properties of the cobalt oxides are discussed in light of the model. 相似文献
25.
Maekawa T Kobayashi T Yamaguchi S Yoshinaga K Igami H Uchida M Tanaka H Asakawa M Terumichi Y 《Physical review letters》2001,86(17):3783-3786
Extraordinary (X) waves are perpendicularly injected for electron Bernstein (B) wave heating into an Ohmically heated plasma from the inboard side in the WT-3 tokamak. Measurements show that absorption does not take place at the electron cyclotron resonance layer nor the upper hybrid resonance layer, but does happen midway between them. This is consistent with the ray tracing prediction, i.e., the poloidal field and poloidal inhomogeneity of toroidal field lead the B waves to have a large parallel refractive index N( parallel) (>1), and the B waves are damped away via the Doppler-shifted cyclotron resonance. 相似文献
26.
We theoretically study the electron transport through a magnetic point contact (PC) with special attention given to the effect of an atomic scale domain wall (DW). The spin precession of a conduction electron is forbidden in such an atomic scale DW and the sequence of quantized conductances depends on the relative orientation of magnetizations between left and right electrodes. The magnetoresistance is strongly enhanced for the narrow PC and oscillates with the conductance. 相似文献
27.
Zhenya Zhang Taisheng Quan Pomin Li Yansheng Zhang Norio Sugiura Takaaki Maekawa 《Applied biochemistry and biotechnology》2004,115(1-3):1033-1039
We studied biogas fermentation from alcohol waste fluid to evaluate the anaerobic digestion process and the production of
vitamin B12 as a byproduct. Anaerobic digestion using acclimated methanogens was performed using the continuously stirred tank reactor
(CSTR) and fixed-bed reactor packed with rock wool as carrier material at 55°C. We also studied the effects of metal ions
added to the culture broth on methane and vitamin B12 formation. Vitamin B12 production was 2.92 mg/L in the broth of the fixed-bed reactor, twice that of the CSTR. The optimum concentrations of trace
metal ions added to the culture liquid for methane and vitamin B12 production were 1.0 and 8 mL/L for the CSTR and fixed-bed reactor, respectively. Furthermore, an effective method for extracting
and purifying vitamin B12 from digested fluid was developed. 相似文献
28.
Fumihiko Maekawa Okiru Komine Katsushige Sato Tomoyuki Kanamatsu Motoaki Uchimura Kohichi Tanaka Hiroko Ohki-Hamazaki 《BMC neuroscience》2006,7(1):1-13
Background
Results of the Women's Health Initiative Memory Study (WHIMS) raised concerns regarding the timing and formulation of hormone interventions. Conjugated equine estrogens (CEE), used as the estrogen therapy in the WHIMS trial, is a complex formulation containing multiple estrogens, including several not secreted by human ovaries, as well as other biologically active steroids. Although the full spectrum of estrogenic components present in CEE has not yet been resolved, 10 estrogens have been identified. In the present study, we sought to determine which estrogenic components, at concentrations commensurate with their plasma levels achieved following a single oral dose of 0.625 mg CEE (the dose used in the WHIMS trial) in women, are neuroprotective and whether combinations of those neuroprotective estrogens provide added benefit. Further, we sought, through computer-aided modeling analyses, to investigate the potential correlation of the molecular mechanisms that conferred estrogen neuroprotection with estrogen interactions with the estrogen receptor (ER).Results
Cultured basal forebrain neurons were exposed to either β-amyloid25–35 or excitotoxic glutamate with or without pretreatment with estrogens followed by neuroprotection analyses. Three indicators of neuroprotection that rely on different aspects of neuronal damage and viability, LDH release, intracellular ATP level and MTT formazan formation, were used to assess neuroprotective efficacy. Results of these analyses indicate that the estrogens, 17α-estradiol, 17β-estradiol, equilin, 17α-dihydroequilin, equilinen, 17α-dihydroequilenin, 17β-dihydroequilenin, and Δ8,9-dehydroestrone were each significantly neuroprotective in reducing neuronal plasma membrane damage induced by glutamate excitotoxicity. Of these estrogens, 17β-estradiol and Δ8,9-dehydroestrone were effective in protecting neurons against β-amyloid25–35-induced intracellular ATP decline. Coadministration of two out of three neuroprotective estrogens, 17β-estradiol, equilin and Δ8,9-dehydroestrone, exerted greater neuroprotective efficacy than individual estrogens. Computer-aided analyses to determine structure/function relationships between the estrogenic structures and their neuroprotective activity revealed that the predicted intermolecular interactions of estrogen analogues with ER correlate to their overall neuroprotective efficacy.Conclusion
The present study provides the first documentation of the neuroprotective profile of individual estrogens contained within the complex formulation of CEE at concentrations commensurate with their plasma levels achieved after an oral administration of 0.625 mg CEE in women. Our analyses demonstrate that select estrogens within the complex formulation of CEE contribute to its neuroprotective efficacy. Moreover, our data predict that the magnitude of neuroprotection induced by individual estrogens at relatively low concentrations may be clinically undetectable and ineffective, whereas, a combination of select neuroprotective estrogens could provide an increased and clinically meaningful efficacy. More importantly, these data suggest a strategy for determining neurological efficacy and rational design and development of a composition of estrogen therapy to alleviate climacteric symptoms, promote neurological health, and prevent age-related neurodegeneration, such as AD, in postmenopausal women. 相似文献29.
In the thermochemical water-splitting iodine–sulfur process for hydrogen production, new polymer electrolyte membranes were applied in an electro-membrane process (electro-electrodialysis, EED) to increase the HI molality of HIx solution (HI + I2 + H2O mixture) to be over quasi-azeotropic. Radiation grafting of a styrene monomer into a poly(ethylene-co-tetrafluoroethylene) base film and subsequent sulfonation provided electrolyte membranes that had ion exchange capacities (IECs) of 1.1–1.6 mmol/g. With the EED of the HIx solutions using [HI] = [I2] = 10 mol/kg at 40 °C the transport number of protons, ratio of permeated quantities of water to the protons, and current efficiency all appeared to depend on the IEC of the resulting membranes. When compared to Nafion, the self-made membranes exhibited lower electric cell resistance, and thereby decreasing up to 32% of the overall energy required in the concentration operation. 相似文献
30.
Prof. Dr. Yasutomo Segawa Takehisa Maekawa Prof. Dr. Kenichiro Itami 《Angewandte Chemie (International ed. in English)》2015,54(1):66-81
Activation of aromatic C? H bonds by a transition metal catalyst has received significant attention in the synthetic chemistry community. In recent years, rapid and site‐selective extension of π‐electron systems by C–H activation has emerged as an ideal methodology for preparing organic materials with extended π‐systems. This Review focuses on recently reported π‐extending C–H activation reactions directed toward new optoelectronic conjugated materials. 相似文献