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61.
Moniruzzaman M Talukder MR Hayashi Y Kawanishi T 《Applied biochemistry and biotechnology》2007,142(3):253-262
The activity and conformation of Chromobacterium viscosum lipase-pretreated with various organic solvents were investigated. The pretreatment of lipase led to a substantial increase
of enzyme activity in AOT (sodium bis [2-ethyl -1-hexyl] sulfosuccinate)/isooctane/water reverse micelles. Among the organic
solvents used, n-hexane was found to be most effective. It was observed that higher hexane content with shorter agitation time and vice versa
had almost the same effect on the initial activity of lipase. The kinetic study showed that the Michaelis constant (K
m) and the substrate adsorption equilibrium constant (K
ad) were reduced by the pretreatment of lipase with hexane, whereas the change in the maximum reaction rate (V
max) was insignificant. The two spectroscopic techniques (Fluorescence spectra of lipase encapsulated in RMs and Fourier transform
infrared [FTIR] spectra of lipase powders) were performed to detect possible conformational changes in the enzyme caused by
the pretreatment. A correlation between the maximum fluorescence intensity and the activity of treated lipase was found as
a function of agitation time. The FTIR spectrum of lipase showed a new shape peak corresponding to 1,500 cm−1 as a result of pretreatment with organic solvents. 相似文献
62.
M. Suzuki H. Kiriyama I. Daito Y. Ochi H. Okada M. Sato Y. Tamaoki T. Yoshii J. Maeda S. Matsuoka H. Kan P. R. Bolton A. Sugiyama K. Kondo S. Kawanishi 《Applied physics. B, Lasers and optics》2011,105(2):181-184
The authors have demonstrated an optical parametric chirped-pulse amplification (OPCPA)/Yb:YAG ceramic thin disk hybrid laser system having hundred mJ level pulse energy sub-picosecond pulse duration with high temporal contrast. At an input chirped-pulse energy of 3.8?mJ from an OPCPA preamplifier an output energy of 130?mJ has been generated from multipass diode-pumped Yb:YAG ceramic thin disk amplifier. A recompressed pulse duration of 450?fs with a contrast level of less than 7.2×10?9 at ?150?ps before the main pulse has been obtained. The contrast level is the highest value achieved in Yb:YAG chirped-pulse amplification (CPA) laser system at 100?mJ level. 相似文献
63.
Rapid and sensitive method for measuring the plasma concentration of doxorubicin and its metabolites
Doxorubicin is an anti-cancer drug with a wide therapeutic range. However, it and its metabolites cause severe side effects, limiting its clinical use. Therefore, measuring the plasma concentration of doxorubicin and its metabolites is important to study the dosing regimen of doxorubicin. We developed a rapid and sensitive method by ultra-high-performance liquid chromatography with fluorescent detection for measuring the plasma concentration of doxorubicin and its metabolites in small volumes (around 10?μL), enabling repeated measurements from the same mouse. The sensitivity of 7-deoxydoxorubicinolone, a major metabolite of doxorubicin, increased about 5 times than those ever reported using conventional HPLC, and the run time was within 3?min. The area under the curve (AUC0-24?h) of doxorubicin was 5.9?μg h/mL similar to the value of 4.16?μg?h/mL obtained previously using a conventional HPLC method. This method would provide information that could be used to refine the therapeutic approach to doxorubicin use. 相似文献
64.
H Shibata H Saito T Kawanishi H Okuda C Yomota 《Chemical & pharmaceutical bulletin》2012,60(8):967-975
Generic versions of Neoral, a microemulsion capsule formulation of cyclosporine, have been approved worldwide. However, there are concerns about the quality and efficacy of the generics due to the formulation specificity and differences in inactive ingredients among products. In this study, we measured the physicochemical properties of both the innovator and the generic formulations, and compared their bioavailability in rats. When the capsule contents were dispersed in water, the absorbance (600?nm wavelength) of generic products was higher than that of the innovator. Whereas the dispersion solution of the innovator in Fed State Simulated Intestinal Fluid was nearly clear, that of all the generics became white and turbid. The mean diameter of the microemulsion (or emulsion) formed in water by the generics was 39.7, 57.7, 64.5, and 74.8?nm, all of which were larger than that of the innovator (26.4?nm). Although the Tmax of the generics tended to be long relative to that of the innovator, there were no significant differences between the innovator and generics with regard to maximum blood concentration (Cmax ) or area under the curve (AUC). These results suggest that the physicochemical differences between the innovator and the generics will not have a significant effect on Cmax or AUC, which is necessary to ensure bioequivalence. 相似文献
65.
M. Suzuki H. Kiriyama I. Daito H. Okada Y. Nakai S. Orimo M. Sato Y. Tamaoki T. Yoshii J. Maeda S. Matsuoka H. Kan P. R. Bolton H. Daido S. Kawanishi 《Applied physics. B, Lasers and optics》2009,97(2):379-382
We report the highest energy broadband laser pulses at a center wavelength of 1030 nm based on optical parametric chirped-pulse amplification (OPCPA). We have demonstrated amplification of 1030 nm femtosecond laser pulses from a broadband Yb oscillator to over 6.5 mJ with a total gain of greater than 107 achieved in a single pass through only 56 mm of gain material at a 10 Hz repetition rate. The amplified spectral bandwidth of 10.8 nm affords recompression to a 230 fs pulse duration following amplification. As an alternative to the regenerative amplifier (RA) this system is one of the more promising candidates for realizing compact, high intensity, direct diode-pumped, high repetition rate femtosecond Yb:YAG chirped-pulse amplification (CPA) in laser systems. 相似文献
66.
S. Oikawa T. Kawanishi K. Higuma Y. Matsuo M. Izutsu 《Photonics Technology Letters, IEEE》2003,15(2):221-223
We propose a resonant-type LiNbO/sub 3/ optical modulator with low halfwave voltage. We optimize the phase constant of the electric wave with thick electrodes to reduce the halfwave voltage. The halfwave voltage of the fabricated modulator with 20-/spl mu/m-thick electrodes is 5.8 V at 10.6 GHz. 相似文献
67.
This paper discusses eye diagram measurement using asynchronous sampling. Simple bit error rate (BER) estimation from eye diagrams is performed. The use of high-speed asynchronous optoelectrical (OE) sampling enables the monitoring of fixed timing Q-factors to be performed simply. 相似文献
68.
A new phase lock loop (PLL) is proposed and demonstrated for clock recovery from an ultrahigh-speed time-division multiplexed (TDM) optical signal. A traveling-wave laser-diode amplifier (TW-LDA) is used as a phase detector, and the cross-correlation component between the optical signal and an optical clock pulse train is detected as a four-wave-mixing (FWM) signal generated in the TW-LDA. A timing clock from a TDM signal is extracted as a prescaled electrical clock, and this prescaled clock is directly recovered from a randomly modulated TDM optical signal. A prescaled 6.3 GHz clock is successfully extracted from a 100 Gb/s signal using the timing comparison output obtained as the cross-correlation between the optical signal and a short (<10 ps) 6.3 GHz optical clock pulse train in the generated FWM light. A comparison of the PLL phase noise with a previously reported gain modulation method is also shown, and the possibility of the Tbit/s operation of this PLL is also considered in the experiments 相似文献
69.
N Kubodera K Miyamoto M Matsumoto T Kawanishi H Ohkawa T Mori 《Chemical & pharmaceutical bulletin》1992,40(3):648-651
1 alpha,25-Dihydroxy-21-norvitamin D3 (3) was synthesized from 1 alpha-hydroxydehydroepiandrosterone (4). Certain biological properties of 3 were examined in comparison with those of 1 alpha,25-dihydroxyvitamin D3 (1) and 1 alpha,25-dihydroxy-21-nor-20-oxavitamin D3 (2) to evaluate the effect of the 21-methyl substituent on biological activities. The differentiation-inducing activity of 3 towards human myeloid leukemia cells was approximately one-fifth of that of 1, while in the binding affinity with chick intestinal cytosolic receptor, 3 was about one-tenth of that of 1. The rather weak effect of 3 on serum calcium levels in normal mice at a dosage of 500 micrograms/kg (intravenous administration) indicates that the essential importance of the 21-methyl moiety may lie in its effect on the regulation of calcium metabolism. 相似文献
70.
F Kiuchi S Nishizawa H Kawanishi S Kinoshita H Ohsima A Uchitani N Sekino M Ishida K Kondo Y Tsuda 《Chemical & pharmaceutical bulletin》1992,40(12):3234-3244
The nematocidal activity of amides and amines having a long alkyl chain against the second-stage larva of dog roundworm, Toxocara canis, was examined. Long chain acyl amides with smaller substituents on the nitrogen showed stronger activity and the activity of cyclic amine amides was stronger than that of acyclic ones. In a series of homologous amides, the activity was dependent on the alkyl chain length: it reached a maximum at an optimal chain length and decreased in both shorter and longer homologues. The relationship between the activity and hydrophobicity of the homologues was analysed by the use of the bilinear model. The hydrophobicity of a compound, which gives a maximal activity, was similar for all neutral amides, but amides which have an additional amine group in the molecule had different values. Tertiary amines and their salts having a long alkyl chain also showed nematocidal activities comparable to those of the corresponding amides. The salts killed the larva at concentrations lower than their critical micell concentration, suggesting that they behave as a single molecule for the nematocidal action. 相似文献