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1.
Recent progress in optical time-division-multiplexed (TDM) transmission technologies is reviewed including optical short pulse generation, time-division multiplexing/demultiplexing, timing extraction, and waveform measurement. The latest 400-Gbit/s transmission experiments based on optical signal processing are presented and the possibility of terabit/second TDM transmission is discussed 相似文献
2.
Self-frequency conversion of ultrashort optical pulses into arbitrary multiwavelength components without the use of a pump is achieved by using supercontinuum generation. Frequency conversion of a randomly-modulated 1.535-1.560 μm, 2.5 ps pulse stream at 6.3 Gbit/s into 1.41-1.64 μm, 0.29-1.0 ps pulse streams is demonstrated for the first time. The method features ultrawide tunability of over 200 nm, and multiwavelength, pulsewidth-tunable output for flexible WDM distribution networks 相似文献
3.
N Kubodera H Watanabe T Kawanishi M Matsumoto 《Chemical & pharmaceutical bulletin》1992,40(6):1494-1499
Six analogues of 1 alpha,25-dihydroxy-22-oxavitamin D3 (OCT) (2), 26,27-dimethyl OCT (5), 26,27-diethyl OCT (6), 24-norOCT (7), 24-homoOCT (8), 24-dihomoOCT (9), and 24-trihomoOCT (10) were synthesized from the 20(S)-alcohol (11) as the common starting material. In the activity inducing differentiation of human myeloid leukemia cells (HL-60) into macrophages, 26,27-dimethyl OCT (5) and 24-homoOCT (8) showed the highest activities. The binding properties of these analogues to the chick embryonic intestinal 1 alpha,25-dihydroxyvitamin D3 (1) receptor are also described. 相似文献
4.
Yuji Kawanishi Yasuzo Suzuki Masako Sakuragi Hisamitsu Kamezaki Kunihiro Ichimura 《Journal of photochemistry and photobiology. A, Chemistry》1994,80(1-3):433-438
The alignment of nematic liquid crystalline (LC) molecules with respect to the LC cell surface was regulated between the homeotropic (H) state and the parallel (P) state by the photochromic trans—cis isomerization of surface-attached azobenzene (Az) moieties. By bringing the angular-selective photoreaction into the system, the orientational order in the P state was significantly improved to attain a universal orientational axis over the entire irradiated area, which was rotatable and erasable photochemically. Laser pulse experiments revealed that the allignment relaxation time τ was reduced from 1000 to 30 ms by increasing the pulse intensity from 10 to 20 mJ cm−2. Strong coupling between the LC and Az molecules was indicated. 相似文献
5.
M. M. R. Talukder M. M. Zaman Y. Hayashi J. C. Wu T. Kawanishi 《Applied biochemistry and biotechnology》2007,141(1):77-83
The thermostability of Cromobacterium viscosum lip ase (EC 3.1.1.3) entrapped in AOT (sodium bis-[2-ethylhexyl] sulfosuccinate) reverse micelles was in creased by the addition
of short-chain polyethylene glycol (PEG 400). Two different approaches were considered: (1) the determination of half-life
time and (2) the mechanistic analysis of deactivation kinetics. The half-life of lipase entrapped in AOT/isooctane reverse
micelles with PEG 400 at 60°C was 28h, ninefold higher than that in reverse micelles without PEG 400. The lip ase entrapped
in both reverse micellar systems followed a series-type deactivation mechanism involving two first-order steps. The deactivation
constant for the first step at 60°C in PEG containing reverse micelles was 0.055 h11, 11-fold lower than that in reverse micelles without PEG, whereas it remained almost constant for the second step. The inactivation
energy of the lip ase entrapped in reverse micelles with and without PEG 400 was 88.12 and 21.97 kJ/mol, respectively. 相似文献
6.
Talukder MM Takeyama T Hayashi Y Wu JC Kawanishi T Shimizu N Ogino C 《Applied biochemistry and biotechnology》2003,110(2):101-112
The activity and stability of Chromobacterium viscosum lipase (glycerolester hydrolase, EC 3.1.1.3)-catalyzed olive oil hydrolysis in sodium bis (2-ethyl-1-hexyl)sulfosuccinate (AOT)/isooctane reverse micelles is increased appreciably when low molecular weight polyethylene
glycol (PEG 400) is added to the reverse micelles. To understand the effect of PEG 400 on the phase behavior of the reverse
micellar system, the phase diagram of AOT/PEG 400/water/isooctane system was studied. The influences of relevant parameters
on the catalytic activity in AOT/PEG 400 reverse micelles were investigated and compared with the results in the simple AOT
reverse micelles. In the presence of PEG 400, the linear decreasing trend of the lipase activity with AOT concentration, which
is observed in the simple AOT reverse micelles, disappeared. Enzyme entrapped in AOT/PEG reverse micelles was very stable,
retaining>75% of its initial activity after 60 d, whereas the half-life in simple AOT reverse micelles was 38 d. The kinetics
parameter maximum velocity (V
max)exhibiting the temperature dependence and the activation energy obtained by Arrhenius plot was suppressed significantly by
the addition of PEG 400. 相似文献
7.
Novel aryl-β-C-glucosidation method using glucal boronate was developed. This protocol can offer several advantages including use of non-toxic, easily handling glucal boronate as a crystalline solid and storable at room temperature for several months. Tri-O-methylnorbergenin (8,10-di-O-methylbergenin), an anti-HIV active bergenin derivative, was concisely synthesized by application of the aryl-β-C-glucosidation method. 相似文献
8.
In this study, we achieved the first total synthesis of natural prunustatin A (1), a novel inhibitor of glucose-regulated protein 78 (GRP78) expression. A key feature included a 15-membered ring macrocyclization, which was successfully accomplished by employing Shiina macrolactonization using 2-methyl-6-nitrobenzoic anhydride (MNBA) and 4-dimethylaminopyridine (DMAP). 相似文献
9.
Kobayashi T Kawai H Suzuki T Kawanishi T Hayakawa T 《Rapid communications in mass spectrometry : RCM》2004,18(10):1156-1160
This report describes an enhancement of the signal intensities of proteins and peptides in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS). When alpha-cyano-4-hydroxycinnamic acid (CHCA) premixed with human transferrin (Tf) was used as a matrix, the signal intensity of insulin was amplified to more than ten times that of the respective control in CHCA without Tf. The detection limit of insulin was 0.39 fmol on-probe in the presence of Tf, while it was 6.3 fmol in the absence of Tf. The signal intensity of insulin was also enhanced when the CHCA matrix was premixed with proteins other than Tf (80 kDa), such as horse ferritin (20 kDa), bovine serum albumin (BSA, 66 kDa), or human immunoglobulin G (150 kDa). The optimum spectrum of insulin was obtained when the added amount of protein was in the range 0.26-0.62 pmol, regardless of the molecular weight of the added protein. Tf and BSA outperformed the other tested proteins, as determined by improvements in the resulting spectra. When the mass spectra of several peptides and proteins were recorded in the presence of Tf or BSA, the signal intensities of large peptides such as glucagon were enhanced, though those of smaller peptides were not enhanced. In addition, the signal enhancement achieved with Tf and BSA was more pronounced for the proteins, including cytochrome C, than for the large peptides. This enhancement effect could be applied to improve the sensitivity of MALDI-TOFMS to large peptides and proteins. 相似文献
10.
Daikoku M. Morita I. Taga H. Tanaka H. Kawanishi T. Sakamoto T. Miyazaki T. Fujita T. 《Lightwave Technology, Journal of》2007,25(1):139-145
In order to realize a future 100-Gb Ethernet (100 GbE) transport, 100-Gb/s transmission without 100-GHz-class electronics and optical time-division-multiplexing technique was demonstrated. By using a differential quadrature phase-shift-keying (DQPSK) modulation format and commercially available electronics, 2- and 50-km transmissions of 100-Gb/s signal were successfully achieved over a standard single mode fiber. The receiver sensitivity, chromatic dispersion, and differential group delay tolerances of 100-Gb/s DQPSK signal were also evaluated. Through these evaluations, the possibility of DQPSK modulation for future 100-GbE transport is verified 相似文献