Carcinogenesis in tissue culture 26: malignant transformation of rat liver cells in vitro associated with paradoxical electrokinetic changes

Periodical examinations of the electrophoretic mobility of rat liver cells of two culture strains, RLC-10(2) and JTC-25.P3, were performed after the treatment with 3.3 X 10(-6) M 4-nitroquinoline 1-oxide (4NQO) for 30 min in culture. As early as 47th day after a single treatment with 4NQO, both control and treated cells of RLC-10(2) were found to produce tumors in animals on back-transplantation. At this stage, however, little difference was yet observed in electrokinetic patterns between the treated cells and the original antecedent cells. In contrast, a subline, JTC-25.P3, treated twice with 4NQO under the same conditions demonstrated a malignant electrokinetic pattern resembling that of rat ascites hepatocarcinoma strains, although its tumorigenicity was not verified. These discrepancies between changes of electrokinetic pattern and tumorigenicity were discussed with special references to the antigenic difference between cultured cell strains and each original host rats.     

Thermal Decomposition of Some Acetoxyoctadecenoates and Acetoxyoctadecadienoates

The rates of the thermal decomposition (dehydroacetoxylation) and the activation energies of the following three samples have been determined: A) acetylated methyl ricinoleate; B) methyl ester mixture of vicinally unsaturated acetoxyoctadecenoates prepared by reacting methyl oleate and mercuric acetate in acetic acid; C) methyl ester mixture of vicinally unsaturated acetoxyoctadecadienoates prepared by reacting methyl linoleate and mercuric acetate in acetic acid. The thermal decomposition is shown to be a first-order reaction.     

Ethanol-tolerant Saccharomyces cerevisiae strains isolated under selective conditions by over-expression of a proofreading-deficient DNA polymerase δ

Ethanol damages the cell membrane and functional proteins, gradually reducing cell viability, and leading to cell death during fermentation which impairs effective bioethanol production by budding yeast Saccharomyces cerevisiae. To obtain more suitable strains for bioethanol production and to gain a better understanding of ethanol tolerance, ethanol-tolerant mutants were isolated using the novel mutagenesis technique based on the disparity theory of evolution. According to this theory evolution can be accelerated by affecting the lagging-strand synthesis in which DNA polymerase δ is involved. Expression of the pol3-01 gene, a proofreading-deficient of DNA polymerase δ, in S. cerevisiae W303-1A grown under conditions of increasing ethanol concentration resulted in three ethanol-tolerant mutants (YFY1, YFY2 and YFY3), which could grow in medium containing 13% ethanol. Ethanol productivity also increased in YFY strains compared to the wild-type strain in medium containing 25% glucose. Cell morphology of YFY strain cells was normal even in the presence of 8% ethanol, whereas W303-1A cells were expanded by a big vacuole. Furthermore, two of these mutants were also resistant to high-temperature, Calcofluor white and NaCl. Expression levels of TPS1 and TSL1, which are responsible for trehalose biosynthesis, were higher in YFY strains relative to W303-1A, resulting in high levels of intracellular trehalose in YFY strains. This contributed to the multiple-stress tolerance that makes YFY strains suitable for the production of bioethanol.     

Coronary artery fistula with left atrial myxoma: report of a case

A 64-year-old male was referred for surgical treatment of left atrial myxoma. Preoperative coronary angiography revealed coronary artery fistula from the left anterior descending artery and the circumflex artery draining into the main pulmonary artery. Operative treatment was performed including resection of the myxoma, patch closure of the atrial septal defect, and closure of the fistula with pledgeted mattress sutures from within the main pulmonary artery on cardiopulmonary bypass. His postoperative course was uneventful, and disappearance of the left atrial myxoma and the coronary artery fistula was ascertained by echocardiography and coronary angiography.     

Photosensitivities and rates of photocrosslinking of poly(vinyl α-cyanocinnamate) and poly(vinyl α-cyanocinnamoxy acetate)

The photosensitivities and the rates of photocrosslinking of poly(vinyl α-cyanocinamate) and poly(vinyl α-cyanocinnamoxyacetate) were investigated. The photocrosslinkings of these polymers proceeded mainly through radical addition, and these polymers showed higher photosensitivities than poly(vinyl cinnamate) and poly(vinyl cinnamoxyacetate), in spite of lower rates of photocrosslinking of the former polymers.     

Multiple scattering effects of MeV electrons in very thick amorphous specimens

Multiple scattering has an important influence on the analysis of microns-thick specimens with MeV electrons. In this paper, we report on effects of multiple scattering of MeV electrons on electron transmission and imaging of tilted and thick amorphous film specimens by experiment and theoretical analysis. Electron transmission for microns-thick epoxy-resin and SiO₂ specimens calculated by the multiple elastic-scattering theory is in good agreement with measurements in the ultrahigh voltage electron microscope (ultra-HVEM) at Osaka University. Electron transmission and electron energy are then presented in an approximate power law. The bright-field ultra-HVEM images of gold particles on the top or bottom surfaces of 5 and 15 μm thick specimens further illustrate the effect of multiple scattering on image quality. The observed top‐bottom effect for the very thick specimens appears to be mainly caused by multiple elastic scattering. With increase in the accelerating voltage from 1 to 2 MV, image blurring, contrast, the signal-to-noise ratio, and the top‐bottom effect are improved because of reduction in the influence of multiple scattering. However, the effect of specimen thickness on image blurring is shown to be stronger than that of accelerating voltage. At the 2 MV accelerating voltage, the 100 nm gold particle can be imaged with less blurring of ∼4 nm when located at the bottom surface of a 15 μm thick epoxy-resin specimen.     

Chromosome observation by scanning electron microscopy using ionic liquid

Electron microscopy has been used to visualize chromosome since it has high resolution and magnification. However, biological samples need to be dehydrated and coated with metal or carbon before observation. Ionic liquid is a class of ionic solvent that possesses advantageous properties of current interest in a variety of interdisciplinary areas of science. By using ionic liquid, biological samples need not be dehydrated or metal-coated, because ionic liquid behaves as the electronically conducting material for electron microscopy. The authors have investigated chromosome using ionic liquid in conjunction with electron microscopy and evaluated the factors that affect chromosome visualization. Experimental conditions used in the previous studies were further optimized. As a result, prewarmed, well-mixed, and low concentration (0.5～1.0%) ionic liquid provides well-contrasted images, especially when the more hydrophilic and the higher purity ionic liquid is used. Image contrast and resolution are enhanced by the combination of ionic liquid and platinum blue staining, the use of an indium tin oxide membrane, osmium tetroxide-coated coverslip, or aluminum foil as substrate, and the adjustment of electron acceleration voltage. The authors conclude that the ionic-liquid method is useful for the visualization of chromosome by scanning electron microscopy without dehydration or metal coating.     

Investigation of high-pressure micro jet technology as an alternative to diamond disc conditioning in ILD CMP

The efficacy of an alternative to conventional diamond conditioning in chemical mechanical planarization (CMP) was evaluated in this study. The high pressure micro jet (HPMJ) system sprays ultra-pure water (UPW) at pressures ranging from 10 to 20 MPa onto a CMP pad to clean the pad of slurry residue, remove embedded slurry particles, and re-establish pad asperities. The system is employed in an ex situ fashion and is compared to in situ and ex situ diamond conditioning as well as using no conditioning. Real-time frictional force acquisition allows for coefficient of friction (COF) analysis, which indicates the extent of pad wear. Removal rate analysis, SEM imagery, and pad surface profilometry are also used to evaluate HPMJ as an alternative conditioning technology. Removal rates significantly lower than those associated with diamond conditioning are obtained for the HPMJ system when UPW conditioning is directly followed by polishing. SEM imagery and pad profilimetry indicate these low HPMJ removal rates are due to differences in pad surface chemistry, not pad surface topography. Experiments including a 30 s silicon wafer polish with slurry following HPMJ conditioning to re-establish pad surface chemistry were performed and result in removal rates that are comparable to those obtained using ex situ conditioning. The removal rates obtained using HPMJ conditioning for relative wafer-platen velocities of 0.31 and 0.62 m/s are 8 and 1% higher than those obtained using ex situ diamond conditioning and 18% lower than those obtained using ex situ diamond conditioning for 0.93 m/s. The average COF values for HPMJ conditioning using the intermediate silicon wafer polishes are 15% lower than average COF values associated with ex situ diamond conditioning, suggesting a possible increase in pad life for the HPMJ system.     

多联式空调机组室外机与环境换热的数值模拟研究

将肋片盘管结构近似为多孔介质,应用CFD模拟方法分析了室外机与环境空气的换热过程,实验测试获得的速度和温度分布结果验证了CFD模拟方法的准确性.应用CFD模拟方法分析了不同布置方案下室外机的进风温度,得出3台室外机呈直线布置时的优化方案:相邻2台机组之间的最小距离为0.2 m,机组主要进风侧与其周围高于机组的竖直壁面的极限间距为0.8 m.     

Chloride chemical form in various types of fly ash

Chloride content is a critical problem for the reuse of fly ash as a raw material in cement, and the method used by recyclers to reduce the fly ash chloride content depends on the chemical form of the chlorides. However, limited information is available on the quantitative distribution of chlorides and the identity of some chlorides such as Friedel's salt. We examined chloride forms and percentages using X-ray absorption near edge structure and X-ray diffraction analyses, as well as corresponding washing experiments. Approximately 15% of the chlorine in raw fly ash was estimated to be in the form of NaCI, 10% in KCl, 50% in CaCl2, and the remainder in the form of Friedel's salt. Fly ash collected in a bag filter with the injection of calcium hydroxide for acid gas removal (CaFA) contained 35% chlorine as NaCl, 11% as KCI, 37% as CaCl2, 13% as Friedel's salt, and the remaining 4% as CaClOH. In fly ash collected in a bag filter with the injection of sodium bicarbonate for acid gas removal (NaFA), approximately 79% of chlorine was in NaCl, 12% was in KCl, and 9% was in Friedel's salt.