In-situ measurement of microwave absorption properties at 2.45 GHz for the polycondensation of lactic acid

For the construction of a microwave-assisted organic synthesis plant, it is necessary to know the dielectric properties of the reaction system. Measurements of the dielectric properties of lactic acid aqueous solution, anhydrated lactic acid, oligo(lactic acid) and water, which are constituent materials in the polycondensation of lactic acid, confirm that dielectric properties decrease as reaction progresses. Calculated microwave penetration depths, obtained from the dielectric properties, show that microwaves penetrate deeply into the reaction system. This work should be useful for the development of microwave-assisted organic syntheses in the chemical industry.     

Contribution of high p34cdc2 kinase activity to premature chromosome condensation of injected somatic cell nuclei in rat oocytes

The present study was undertaken to clarify the relationship between the p34cdc2 kinase activity of in vitro-aged or enucleated rat oocytes and the premature chromosome condensation (PCC) of microinjected cumulus cell nuclei. Wistar rat oocytes were placed in vitro up to 120 min after the animal was killed. The p34cdc2 kinase activity of the oocytes decreased in a time-dependent manner. The incidence of PCC was higher when nuclear injection into intact oocytes was completed in 15-45 min rather than 46-120 min. When rat oocytes were enucleated for subsequent nuclear injection, the p34cdc2 kinase activity transiently increased soon after enucleation but drastically decreased after 30 min. Removal of the cytoplasm instead of the meta-phase-plate did not affect the p34cdc2 kinase activity even after 60 min. PCC occurred in intact and cytoplasm-removed oocytes but not in enucleated oocytes. In contrast, oocytes from BDF1 mice exhibited a p34cdc2 kinase level twice that of rat oocytes and supported PCC despite enucleation. The p34cdc2 kinase level of intact rat oocytes was reduced to the equivalent level of aged (120 min) or enucleated (+60 min) oocytes by a 45 min treatment with roscovitine, an inhibitor of p34cdc2 kinase. None of the roscovitine-treated oocytes supported PCC while half of the control oocytes did. When rat oocytes were treated with MG132, a proteasome inhibitor, delayed inactivation of the p34cdc2 kinase was observed in the MG132-treated oocytes. A significantly higher proportion of the MG132-treated oocytes supported PCC when compared with the control oocytes. Moreover, a higher proportion of MG132-treated and enucleated oocytes carried two pseudo-pronuclei after cumulus cell injection and developed to the two-cell stage when compared with the enucleated oocytes at the telophase-II stage. These results suggest that the decreased level of p34cdc2 kinase activity in aged or enucleated rat oocytes is responsible for their inability to support PCC of microinjected donor cell nuclei and that inhibition of p34cdc2 kinase inactivation by chemicals such as MG132 is in part effective for rat oocytes to promote PCC and further development.     

Digital fault location for high resistance grounded transmissionlines

This paper demonstrates that the presence of multiple load taps cannot be neglected for single-phase-to-ground fault location. A new method has been developed taking this into consideration, that can be applied to correct the location error due to intermediate power sources. Then fault location methods for parallel double-circuit two-terminal transmission lines are discussed. Finally, a new fault location method is proposed for high-resistance grounded double-circuit transmission lines with three terminals     

Preparation of Cu2ZnSnS4 thin films by sulfurizing electroplated precursors

Cu₂ZnSnS₄ (CZTS) thin films were prepared by sulfurizing precursors deposited by electroplating. The precursors (Cu/Sn/Zn stacked layers) were deposited by electroplating sequentially onto Mo-coated glass substrates. Aqueous solutions containing copper sulfate for Cu plating, tin sulfate for Sn plating and zinc sulfate for Zn plating were used as the electrolytes. The precursors were sulfurized by annealing with sulfur at temperatures of 300, 400, 500 and 600 °C in an N₂ gas atmosphere. The X-ray diffraction peaks attributable to CZTS were detected in thin films sulfurized at temperatures above 400 °C. A photovoltaic cell using a CZTS thin film produced by sulfurizing an electroplated Sn-rich precursor at 600 °C exhibited an open-circuit voltage of 262 mV, a short-circuit current of 9.85 mA/cm² and an efficiency of 0.98%.     

Wide bandwidth of over 50 GHz travelling-wave electrodeelectroabsorption modulator integrated DFB lasers

A travelling-wave electrode electroabsorption modulator integrated distributed feedback laser to overcome the CR-induced bandwidth limitation is developed. A bandwidth much wider than 50 GHz is achieved. A 40 Gbit/s eye-diagram is observed. The device has a potentiality for future 100 Gbit/s transmission     

Hyperbranched poly(arylene ether phosphine oxide)s

Summary New AB₂ and A₂B monomers, bis(4-fluorophenyl)-4'-hydroxyphenylphosphine oxide and bis(4-hydroxyphenyl)-4'-fluorophenyl-phosphine oxide were prepared and converted to corresponding hyperbranched poly(arylene ether phosphineoxide)s with hydroxyphenyl and fluorophenyl end functional groups. While the dihydroxy monomer gave a low molecular weight polymer, the difluoro monomer produced a high molecular weight hyperbranched polymer. The glass transition temperature of the obtained polymers was 266°C and 230°C, and 5% weight loss temperature was 491 °C and 391 °C, respectively. The fluorophenyl-terminated hyperbranched polymer was soluble in CHCl₃, but the hydroxyphenyl-terminated polymer was not soluble in CHCl3 even though it has lower molecular weight than the fluorophenyl-terminated polymer, indicating that properties of the hyperbranched polymers markedly depend on end functional groups as well as their molecular weight. Received: 23 August 2000/Revised version: 19 October 2000/Accepted: 31 October 2000     

Use of multivariate analysis for the improvement in prediction accuracy of bacterial aerobic plate count by flow cytometry

Flow cytometry (FCM) and aerobic plate count (APC) by the culture method were performed on green tea samples spiked with Escherichia coli type strain NCTC9001 (ATCC11775) solutions of different concentrations. In FCM, fluorescence signals from multiple stained bacteria and other fluorophores are detected using detector channels, and recorded as events with a voltage at each channel. FCM data were analyzed in two ways: conventional and multivariate analysis. In the former, the number of events with voltages larger than the defined threshold values was regarded as the predicted APC. In the latter, voltage histograms of all channels were obtained and merged horizontally to serve as explanatory variables. Then a partial least squares regression (PLSR) model was built to predict APC from the histogram data. The coefficient of determination (R²) and the root mean square error (RMSE) between APC by the culture method and that predicted by conventional FCM were 0.916 and 1.08 cfu/ml². The APC values predicted by the PLSR model and those measured were in good agreement with R² of 0.982 and RMSE of 0.417 cfu/ml, which verified the potential of the proposed method for improving APC prediction accuracy by FCM.     

Stone-Wales Rearrangement Pathways from the Hinge-Opened [2+2] C60 Dimer to Ipr C120 Fullerenes. Vibrational Analysis of Intermediates

Abstract

Possibility of the previously proposed hinge-opened product 2 of [2+2] C₆₀, dimer 1 transforming itself into IPR C₁₂₀ fullerenes by a series of generalized Stone-Wales (GSW) rearrangements has been tested by seeking all topologically acceptable pathways with the help of a graphical search program. the first IPR isomer 4 appeared after 20 GSW steps from the wide-bridged dumb-bell shaped precursor 3. More than 1,000 C₁₂₀ fullerene structures were generated during subsequent ten GSW steps, but the outstanding T _d C₁₂₀ global minimum 5 was not reached. Semiempirical vibrational calculations predict characteristic transition in the vibrational spectra in the course of rearrangement pathway.     

Natural convection heat transfer from a horizontal cylinder in liquid sodium: Part 2: generalized correlation for laminar natural convection heat transfer

Rigorous numerical solution of natural convection heat transfer, from a horizontal cylinder with uniform surface heat flux or with uniform surface temperature, to liquid sodium was derived by solving the fundamental equations for laminar natural convection heat transfer without the boundary layer approximation. It was made clear that the local and average Nusselt numbers experimentally obtained and reported in part 1 of this paper were described well by the numerical solutions for uniform surface heat fluxes, but that those for uniform surface temperatures could not describe the angular distribution of the local Nusselt numbers and about 10% underpredicted the average Nusselt numbers. Generalized correlation for natural convection heat transfer from a horizontal cylinder with a uniform surface heat flux in liquid metals was presented based on the rigorous theoretical values for a wide range of Rayleigh numbers. It was confirmed that the correlation can describe the authors’ and other workers’ experimental data on horizontal cylinders in various kinds of liquid metals for a wide range of Rayleigh numbers. Another correlation for a horizontal cylinder with a uniform surface temperature in liquid metals, which may be applicable for special cases such as natural convection heat transfer in a sodium-to-sodium heat exchanger etc. was also presented based on the rigorous theoretical values for a wide range of Rayleigh numbers. These correlations can also describe the rigorous numerical solutions for non-metallic liquids and gases for the Prandtl numbers up to 10.     

Isolated retrograde amnesia following viral encephalitis

We describe a patient who presented with isolated retrograde amnesia of 2-year duration after recovery from viral encephalitis. The patient was a 29-year-old right-handed male dentist and was admitted to our hospital with a complaint of generalized convulsion. Cerebrospinal fluid (CSF) showed mononuclear pleocytosis. Neuroradiological examinations (X-ray CT, MRI and 123I-IMP SPECT) revealed no significant abnormality. Immunological method showed no specific increase of viral antibody titers. However, with a tentative diagnosis of viral encephalitis, administration of acyclovir was started. After 3 weeks he became comprehensive, and several kinds of neuropsychological tests were performed. His intelligence and immediate memory were normal, and his procedural memory of dentist was intact. On the other hand, he could not recall any information about events, both personal and public, occurred within 2 years before the onset of present illness. His autobiographical memory disorder was also demonstrated using a series of weekly comic. In isolated retrograde amnesia following viral encephalitis like this case, memory of relatively short time duration, acquired prior to the onset of present illness, tend to be disturbed.