Preparation of α,ω-bis(p-vinylbenzyl)-terminated polystyrene and α-methylstyrene tetramer

Summary Telechelic macromers composed of only hydrocarbon were prepared by the end-capping reactions of two-ended living polystyrenes and dianion of -methylstyrene tetramer with p-vinylbenzyl chloride. ,-bis(p-vinylbenzyl)polystyrene obtained was found to have a narrow molecular weight distribution and high functionality. In the end-capping reaction of the tetrameric dianion, the yield of ,-(p-vinylbenzyl)-methylstyrene tetramer was 84 % at most, profoundly depending on the concentration of the dianion. To isolate the functionalized tetramer, the fractional dissolution of a crude product was performed with H₂O/MeOH and the result was desirable.     

Studies of the crystallisation of gallium hydroxide precipitated from hydrochloric acid solutions by various alkalis

Gallium hydroxide precipitated from aqueous gallium chloride solution on addition of alkalis at varying pH have been aged in the mother liquors for different periods of time. The resulting precipitates have been examined by X-ray diffraction and i.r. spectrophotometry. It is found that the precipitate, separated immediately from the mother liquor after preparation, exists in an amorphous type and transforms to α-gallium oxyhydroxide during aging independent of pH.     

Formation and Crystallization in the Yttrium Aluminosilicate Glasses Containing Zinc Oxide

Formation of yttrium aluminosilicate glasses containing zinc oxide from batches melted at 1550°C was investigated. Densities, thermal expansion coefficients, and Vickers hardnesses were measured for some glasses. In a specific compositional region, crystals with a convex and pyramidal habit were observed on the glass surface. The crystal was identified as ZnAl₂O₄ (gahnite) which has a Moh's hardness number of ∼8.     

烧结钢的应力-弹性及塑性应变曲线的制作与评价

根据拉伸试验(TT)得到的应力-应变曲线和通过声音脉冲方法(APM)得到的声速,计算并比较了烧结钢的弹性模量(E)和泊松比(v).Err和vTT的值分别小于EAPM和vAPM,这是因为在烧结钢的应力-应变中不仅包含了弹性应变,而且也包含了塑性应变.利用由EAPM和vAPM的值计算得到的纵向和横向弹性应变,从纵向和横向应力-应变中分离出纵向和横向的塑性应变.在小应变时烧结钢没有显示线性应力-应变的情况下,可以很简单地由纵向塑性应力表中求出弹性极限或0.2%的屈服强度.对于同样的应力,每个样品的弹性应变和塑性应变的不同,可以由基于孔隙特征(孔隙的大小、形状、相互连接及微观结构的不同)的模型来解释.     

Disulfide bond formation in refolding of thermophilic fungal protein disulfide isomerase

Disulfide bond formation in the refolding of thermophilic fungal protein disulfide isomerase (PDI) was investigated. It was revealed that (i) a disulfide bond buried inside the molecule is preferentially formed and contributes to the thermal stability and the isomerizing power of PDI, and (ii) formation of disulfide bonds in active sites located on the molecular surface causes deformation of the optimum conformation resulting in a decrease in the thermal stability.     

Production of recombinant human midkine in yeast, Pichia pastoris

Recombinant human midkine was expressed in the cells of Pichia pastoris under the control of the AOX1 gene promoter. The expression of midkine was efficiently induced by methanol in a high cell density fermentation. Approximately 0.3 g/l culture of midkine accumulated in the cells by 72 h after induction. When the cells were disrupted, midkine was recovered in an insoluble form, and was insoluble even in the presence of 7 M urea. The precipitate was dissolved in the buffer solution (pH 8) containing 8 M guanidine hydrochloride, 10 mM dithiothreitol, 1 mM EDTA and 50 mM Tris-Cl, and then, midkine was renatured by dialysis at high concentration against the buffer solution (pH 8) containing 0.5 M sodium chloride and 20 mM Tris-Cl. The renatured midkine was recovered using a SP-Sepharose column, and purified further by Heparin-Sepharose column chromatography. Approximately 64 mg/l culture of the purified midkine was obtained. The amino acid sequence of amino-terminus and the amino acid composition of midkine were the same as those of Met-midkine that has a methionine residue at the amino-teminus. Mass spectrometry of purified Met-midkine showed a mass of 13370.7 Da (average), almost the theoretical mass for it. The Met-midkine enhanced the proliferation of Chinese hamster ovary (CHO) cells.     

Deficiency of Lipin2 Results in Enhanced NF-κB Signaling and Osteoclast Formation in RAW-D Murine Macrophages

Lipin2 is a phosphatidate phosphatase that plays critical roles in fat homeostasis. Alterations in Lpin2, which encodes lipin2, cause the autoinflammatory bone disorder Majeed syndrome. Lipin2 limits lipopolysaccharide (LPS)-induced inflammatory responses in macrophages. However, little is known about the precise molecular mechanisms underlying its anti-inflammatory function. In this study, we attempted to elucidate the molecular link between the loss of lipin2 function and autoinflammatory bone disorder. Using a Lpin2 knockout murine macrophage cell line, we showed that lipin2 deficiency enhances innate immune responses to LPS stimulation through excessive activation of the NF-κB signaling pathway, partly because of TAK1 signaling upregulation. Lipin2 depletion also enhanced RANKL-mediated osteoclastogenesis and osteoclastic resorption activity accompanied by NFATc1 dephosphorylation and increased nuclear accumulation. These results suggest that lipin2 suppresses the development of autoinflammatory bone disorder by fine-tuning proinflammatory responses and osteoclastogenesis in macrophages. Therefore, this study provides insights into the molecular pathogenesis of monogenic autoinflammatory bone disorders and presents a potential therapeutic intervention.     

Thermodynamic modeling of hydrogen fueling process from high-pressure storage tank to vehicle tank

This study develops a hydrogen fueling station (HFS) thermodynamic model that simulates the actual fueling process in which hydrogen is supplied from a high-pressure (HP) storage tank into a fuel cell electric vehicle (FCEV) tank. To make the model as accurate as possible, we use the same components and specifications as in actual HFSs, such as a pressure control valve, a pre-cooling system, and an FCEV tank. After the components and their specifications are set, pressure and temperature profiles are set as the HP tank supply conditions. Based on the pressure and temperature profiles, the model solves for the temperature, pressure, and mass flow rate of hydrogen at each downstream position, including the inside of the vehicle tank. The values predicted by the model are compared with experimental data, and we show that the developed model makes it possible to accurately simulate those values at any position during the fueling process.     

基于可再生能源的全球电气化路径与远景分析

为满足清洁能源转型的深度脱碳要求,描绘一幅基于可再生能源电气化的蓝图,全面阐述了基于可再生能源的电气化路径,分析其在工业、交通、建筑等部门面对的挑战,评估不同技术路径的应用前景和效益,提出政策、技术和市场方面的措施建议。研究结果表明,基于可再生能源的电气化路径不仅技术可行,同时也会产生重要的经济和社会效益。