Differential chemosensitivity in oncogene-transformed cells

The effects of anticancer drugs on cell growth have been investigated by MTT colorimetric assay using mouse and rat cultured cells transformed by various oncogenes and tumor viruses. Aclarubicin, mitomycin C and 1-hexylcarbamoyl-5-fluorouracil showed higher growth-inhibitory activities toward transformed cells than those toward the normal counterparts. Nimustine, bleomycin and 5-fluorouracil also showed selective growth-suppressive activities toward transformed cells except for a few cell lines. ras-oncogene-transformed cells were more sensitive toward 5-fluorouracil and 1-hexylcarbamoyl-5-fluorouracil than the normal parent cells and other transformed cells. These drugs would thus be effective in the chemotherapy of ras-induced cancer.     

Who wins when price information is more ubiquitous? An experiment to assess how infomediaries influence price

Internet retailers often make use of price search services (infomediaries) that have the effect of reducing consumer search and expanding seller market presence. Research on price and advertising suggests that this may not be a profitable strategy. We develop an experimental posted-offer market to estimate the impact of infomediaries on price of homogenous goods. We analyze panel data from a range of market conditions that address how infomediaries services affect both seller-level offered price as well as market-level transacted price. We find that, while sellers attempt to extract higher prices through a higher initial offer price when using an infomediary, they fail to successfully collect it; transacted prices remain largely unchanged. As a consequence the benefits of infomediaries fall primarily to the buyer who faces largely unchanged transacted prices, and substantially reduced search costs. Search costs are, in essence shifted to the seller. Sellers who participate in this sort of price comparison should be aware that they are following a high-volume/low profit per unit strategy.     

Evaluation of Two Sets of Sorghum Bagasse Samples as the Feedstock for Fermentable Sugar Recovery via the Calcium Capturing by Carbonation (CaCCO) Process

Abstract: Sorghum bagasse samples from two sets (n6 and bmr6; n18 and bmr18) of wild-type and corresponding “brown midrib” (bmr) mutant strains of sweet sorghum were evaluated as the feedstock for fermentable sugar recovery via the calcium capturing by carbonation (CaCCO) process, which involves Ca(OH)₂ pretreatment of bagasse with subsequent neutralization with CO₂ for enzymatic saccharification. Saccharification tests under various pretreatment conditions of the CaCCO process at different Ca(OH)₂ concentrations, temperatures or residence periods indicated that bmr strains are more sensitive to the pretreatment than their counterparts are. It is expected that variant bmr6 is more suitable for glucose recovery than its wild-type counterpart because of the higher glucan content and better glucose recovery with less severe pretreatment. Meanwhile, bmr18showed higher scores of glucose recovery than its counterpart did, only at low pretreatment severity, and did not yield higher sugar recovery under the more severe conditions. The trend was similar to that of xylose recovery data from the two bmr strains. The advantages of bmr strains were also proven by means of simultaneous saccharification and fermentation of CaCCO-pretreated bagasse samples by pentose-fermenting yeast strain Candida shehatae Cs 4R. The amounts needed for production of 1 L of ethanol from n6, bmr6, n18, and bmr18samples were estimated as 4.11, 3.46, 4.03, and 3.95 kg, respectively. The bmr strains seem to have excellent compatibility with the CaCCO process for ethanol production, and it is expected that integrated research from the feedstock to bioprocess may result in breakthroughs for commercialization.     

Microorganisms in landfill bioreactors for accelerated stabilization of solid wastes

Landfill bioreactors (LBRs) with management of leachate and biogas have presented numerous advantages such as accelerated stabilization of solid wastes, reduced amount of leachate, and in situ leachate treatment. Such advantages have minimized environmental risks, have allowed extension of the useful life of the landfill site, and have fostered cost reduction. LBRs of three types have been developed using both anaerobic and aerobic modes: anaerobic, aerobic, and hybrid. Microorganisms in landfills cause various reactions related with organic fractions and heavy metals. Such functions have been stimulated in LBRs by recirculation of leachate with or without aeration. To date, most studies of microorganisms in LBRs have analyzed bacteria and archaea based on 16S rRNA genes and have analyzed fungi based on 18S rRNA genes from a taxonomical viewpoint. Indicator genes for specific functions in LBRs such as nitrification, denitrification, and methane production have also been monitored. The population dynamics of microorganisms in LBRs have been partially clarified, but the obtained data remain limited because of highly heterogeneous features of solid wastes inside LBRs. Systematic monitoring of microorganisms should be established to improve LBR performance.     

基于边界积分方程法的圆弧齿轮强度分析

提出用边界积分方程法(boundary integral equation method,BIEM)进行圆弧齿轮强度分析的设汁方法。在研究中依据弹性理论的柯西型积分,建立适合于各种载荷作用轮齿不同位置的齿轮强度分析数学模型。在理论方程式建模中采用间接式边界积分方程法,以应力函数作为解析对象,直接求解齿轮应力、轮齿刚度变形等。文中方法具有理论公式推导简捷、软件设计容易、使用方便的优点。本研究还进行了软件设计和实例应用解析,并通过与其他方法的结果比较证实本方法正确有效和实用价值。     

改定JASS 5における再生骨材コンクリ一トの規定の概要

日本建築学会建築工事標準仕様書JASS 5鉄筋コンクリート工事が2009年2月に大改定された.今回の改定では、新技術の取込みはもとより、エコセメントや再生骨材コンクリートの節の新設などによる環境配慮への取組みの強化、かぶり厚さなどの規定の検査方法の充実、計画供用期間の級の超長期への対応や耐久性向上にかかわる乾燥収縮率*ヤング係数*許容ひび割れ幅などのコンクリートの品質基準の設定、調合強度の定め方の合理化を目指した構造体強度補正値(S値)の適用の拡大など、きわめて多岐にわたっている.また、水密コンクリートをはじめ特別な仕様のコンクリートについて、より実情に即した形で規定の充実が図られている.この報告は、そのうち、再生骨材コンクリートに関する規定について紹介する.     

Electron-beam doping-electron radiation effects in impurity overlayers and semiconductor substrates

3-9 MeV electrons were used to introduce impurity Ge atoms into Si wafers from Ge sheets, which are in contact with a Si surface at 20-60‡C in water bath. Concentration-dependent diffusivities of ∼10-18-10^-14 cm²sec^-1 for Ge in Si were measured. Activation energies of sputtering yield for Ge and of the diffusivity of Ge in Si are estimated to be ∼0.3 eV and ∼0.58 eV, respectively. In a case of hot (∼250‡C) irradiation in ∼1x10^-3 Torr vacuum, also the similar concentration profiles of impurity atoms in the substrates were observed.     

Factors affecting soluble selenium removal by a selenate-reducing bacterium Bacillus sp. SF-1

High concentrations of soluble selenium, selenate and selenite, have acute and chronic toxicity toward living things. With the aim of developing a biological process for selenium removal, the effects of a variety of parameters on the reduction of soluble selenium by a Bacillus sp. strain SF-1, which is capable of reductively transforming selenate into selenite and, subsequently, into nontoxic insoluble elemental selenium, were studied. The bacterial strain could effectively reduce 20 mM of selenate to selenite and 2 mM of selenite to elemental selenium in the presence of an appropriate carbon source and in the absence of oxygen. The reduction rate of selenate to selenite was much higher than that of selenite to elemental selenium, resulting in the transient accumulation of selenite during selenate reduction. The selenate reduction rate increased with increases in the selenate concentration up to 20 mM, while the rate of selenite reduction decreased sharply at selenite concentrations of more than 2 mM. The elemental selenium transformed from selenate via selenite was found both inside and outside the cells. Bacillus sp. SF-1 was able to utilize a variety of organic acids or sugars as a carbon source in selenate reduction. Although the copresence of sulfate did not inhibit selenate reduction, it was completely inhibited by some other oxyanions, including nitrate. A model sequencing batch system using the bacterial strain was developed and exhibited good performance in the treatment of wastewater containing high concentrations of selenate.     

Photovoltaic system using buck-boost PWM power inverter

This paper presents a buck-boost PWM power inverter and its application for the residential photovoltaic system. The PWM power inverter is realized by driving an inverter constructed with a high-frequency buck-boost chopper in the discontinuous conduction mode (DCM). The photovoltaic system with the power inverter has the following advantages: (1) the power generated by the photovoltaic array can be transferred to the load and the utility line under any array voltage; (2) isolation between the photovoltaic array and the utility line is performed by a small high-frequency reactor operating as energy storage element; (3) there is no need of a reactor to link the utility line; (4) unity power factor operation is provided; and (5) the system configuration is very simple. the input-output characteristics of the system are analyzed. As a result, the ripple component of the array current and the power flow between the interface and the utility line are derived and verified experimentally.