Suppression of proliferative cholangitis in a rat model with direct adenovirus-mediated retinoblastoma gene transfer to the biliary tract

Two genes for Ca2+-dependent protein kinases, PCaPK-alpha and PCaPK-beta, were isolated from a Paramecium genomic DNA library. The coding region of PCaPK-alpha encoded 481 amino acids and that of PCaPK-beta encoded 493 amino acids, predicting molecular masses of 55603 Da and 57131 Da for each putative protein. The sequences of the protein kinase catalytic domains of PCaPK-alpha and PCaPK-beta were closely related to those of the Ca2+-dependent protein kinases (CDPKs) from Plasmodium, Eimeria, and several plants, and the catalytic region of the Ca2+/calmodulin-dependent protein kinase family (35-48% identity). In the junction region between the catalytic and regulatory regions, only 9 of 31 amino acid residues are the same in the two Paramecium genes, and the sequences encoded in the Paramecium genes differ from those in the plant CDPK genes in about 20 of 31 residues in the junction region. The C-terminal region of the Paramecium kinases shared sequence similarity with Paramecium calmodulin (30-34% identity). Two Ca2+-dependent protein kinases previously characterized from Paramecium (52 kDa CaPK-1, and 50 kDa CaPK-2) are activated by Ca2+ in the micromolar concentration range and they directly bind Ca2+ in a 45Ca2+ overlay blot assay. The size predicted from the genes, the presence of four putative Ca2+-binding motifs encoded in PCaPK-alpha and PCaPK-beta, and the immunological cross-reaction of expressed cloned fragments of these genes with CaPK-2, suggest that they encode proteins of the same family.     

Antioxidative activities of tocotrienols on phospholipid liposomes

Antioxidative activity of tocotrienol (Toc3) was studied in the oxidation of dilinoleoylphosphatidylcholine (DLPC) liposomes. The objective was to measure the differences in the antioxidative activities betweenα-Toc3 andα-tocopherol (α-Toc), and betweenγ-Toc3 andγ-Toc. When each antioxidant was added to the already prepared DLPC liposome solution, the antioxidative activity of Toc3 was larger than that of Toc. However, when incorporated into the liposomal membrane, the antioxidative activities of Toc3 and Toc were the same and were intermediate between those of the added Toc3 and Toc. When added to the liposome solution, the consumption of Toc3 during the induction period was larger than that of Toc. When incorporated into the liposomal membrane, the consumptions of Toc3 and Toc were the same and were intermediate between those of the added Toc3 and Toc. These results suggest that the reactions of Toc3 and Toc with phospholipid peroxide within the membrane are inhibited to a different degree depending on the dosing manner of Toc3 and Toc. Namely, the degree of inhibition decreases in the following order: Toc(added)> Toc(incorporated)= Toc3(incorporated)> Toc3(added).     

Morphologies and mechanical properties of polylactide blends with medium chain length poly(3‐hydroxyalkanoate) and chemically modified poly(3‐hydroxyalkanoate)

Blends of bacterial poly(3‐hydoroxyalkanoate) (PHA) with a medium‐length side chain and polylactide (PLA), and blends of the chemically modified PHA (ePHA) with PLA, were prepared. The morphologies, some physical properties, and thermal behavior of the blends based on PLA were investigated by electron microscopies, testing machines, and a differential scanning calorimeter, respectively. A blend of uncrystallized rubbery second components, PHA and ePHA, produced an increase in the impact toughness of the PLA blends in contrast to a decrease in the tensile strength value. PHA, especially, with an inserted epoxy group side chain was more effective in improving the morphology and the physical properties than PHA. The ePHA particles existed in the PLA domain as a dispersed phase having a size of 0.1–1 μm. The results of the biodegradation test demonstrated that the PLA blends still maintained their biodegradability and were more accessible to hydrolysis and microbial attack, resulting in a greater weight loss than the pure PLA. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2363–2369, 2004     

预应变对不同含碳量钢材疲劳特性的影响

通过对非预应变15号、35号和45号钢及其各种预应变材料进行实验,研究了预应变量对不同含碳量钢材疲劳强度和疲劳裂纹发生的影响。实验结果表明:在相同的预应变预量的条件下,材料的疲劳极限随含碳量的增加而提高;当预应变量较低时,预应变材料的疲劳极限低于非预应变材料,含碳量越高降低的程度越明显;当预应变量较高时,材料的疲劳极限随预应变量的增加而恢复或提高。     

Synthesis and properties of novel biodegradable polyamides containing α-amino acids

Polyamides are useful biomaterials owing to their biodegradability and good mechanical strength. We have obtained novel polyamides from succinylsarcosine and ethylenediamine by polycondensation in water using 1-ethyl-3-(3-dimethyl-aminopropyl)-carbodiimide (EDC·HCl) and 1-hydroxybenzotriazole. The molecular weight of the obtained polyamides depends on the concentration of the monomers or EDC·HCl, and reached a maximum of over 200,000. The optimal polycondensation temperature was between 10 and 20 °C. We also obtained copolymers of succinylsarcosine and succinylisoleucine by the same method. When the succinylisoleucine content increased, the obtained polyamides showed lower melting points, higher enzymatic degradability, and higher cell adhesion rates. Thermally responsive polyamides containing an elastin-derived pentapeptide, VPGVG, succinylsarcosine, and succinylisoleucine were obtained by the same method. The temperature-dependent precipitation of the polyamide occurred reversibly, and the temperature of precipitation varied from below room temperature to over 80 °C, depending on the ratios of succinylsarcosine and succinylisoleucine.     

Identification of trail pheromone precursors from Subterranean termite,Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae)

Whole-body extracts of the termite,Coptotermes formosanus Shiraki served for examining the presence of trail pheromone precursor(s). Three trail pheromone precursor candidates, identified as dodecatrienyl stearate, dodecatrienyl oleate, and dodecatrienyl linoleate, were isolated using various chromatographic methods in conjunction with bioassay and by capillary GC-MS analyses.     

煤焦气化反应过程中灰的熔融特性变化

抽样选出具有代表性的一种高灰熔点煤种和一种低灰熔点煤种,在TGA-51H型高温热天平上进行煤焦-O2、煤焦-CO2和煤焦-水蒸气气化反应实验,通过扫描电镜(SEM)考察了不同气氛下煤焦气化反应过程中高、低灰熔点煤灰的熔融变化过程,并利用EDX分析了灰的熔融机制。实验结果表明:同种煤样还原性气氛下的灰熔点比氧化性气氛下低;相同条件下灰在CO2气氛下的灰熔点比其在水蒸气气氛下低。在气化反应的过程中,由于气化反应为强吸热过程,大部分热量提供给煤炭气化反应,导致Ca与Fe元素的还原反应进行缓慢,灰熔融温度比较高。     

Preparation and properties of soluble and colorless fluorine-containing photoreactive polyimide precursors

Photoreactive polyimide precursors, which are readily soluble in common organic solvents and optically transparent at light of 365 nm wavelength (i-line), similar to aliphatic polyimide precursors, were obtained by polycondensation of biphenyltetracarboxylic dianhydride (BPDA) and fluorine-containing diamine compounds. In particular, the polyimide precursor prepared from 2,2 bis(3-amino-4-methylphenyl) hexatluoropropane showed high solubility in common organic solvents and complete transparence at i-line wavelength. A 3 μm thick film of the polyimide precursor on a silicon wafer was exposed and developed, and offered high resolution (0.5μm line) patterns with an aspect ratio of 6.0. This polymide precursor swells very little in the developing solvent, resulting in the high resolution. Conversion of polyamic acid to polyimide at several curing temperatures was observed by infrared spectrophotometer and thermogravimetry.     

Dissolution inhibition mechanisms of naphthoquinone diazides

Dissolution inhibition mechanisms of naphthoquinone diazides in novolak based positive photoresists were investigated from three different aspects:

• ? Dipolar interaction.
• ? Interfacial chemical reactions.
• ? Chemical structures of naphthoquinone diazides.

The results suggest that there exists a hydrogen bonding interaction between the compounds with the matrix novolak resin and that naphthoquinone diazides would crosslink the resin in contact with an alkaline developer, both of which contribute to dissolution inhibition mechanisms. However, there seems to exist another dissolution inhibition mechanism; namely, 1,2-naphthoquinone diazide does not inhibit dissolution of the matrix novolak resin at all while a clear dissolution inhibition effect Is observed for its derivatives containing sulfonyl groups. In the present paper, three dissolution inhibition mechanisms of naphthoquinone diazides will be proposed.