薄层色谱画像解析法快速判定鱼肉的脂质氧化度

为了快速判定鱼肉的脂质氧化度,建立薄层色谱画像(thin layer chromatography image,TLC-i)解析法快速测定鱼类氧化生成的极性化合物含量。取黄鳍金枪鱼油0.5μL点样于硅胶板上,用正己烷-乙醚-醋酸(30∶70∶1,V/V)的混合液展开12 min后,3%醋酸铜磷酸溶液喷雾显色,150℃加热15 min后,将氧化生成的极性化合物通过面积分析软件进行半定量分析。结果表明,此方法测得的极性化合物含量与常用的过氧化值(peroxide value,POV)、羰基值(carbonyl value,CV)相比,具有较好的相关性,相关系数分别为0.993 8和0.972 5。将此方法用于判定远东多线咸鱼在4℃贮藏期间的脂质氧化情况,发现极性化合物含量与POV具有较好的正相关性(R~2=0.962 5)。将此方法用于判定盐渍红鲑在-5℃贮藏期间的脂质氧化情况,发现极性化合物含量与a*值具有较好的负相关性(R~2=-0.822 9)。结果表明,该方法具有简单化、快速化、微量化、可视化的优点,且不需要昂贵的设备,适合鱼肉脂质氧化度的快速评价。     

Spectroscopic Measurement of Shock Waves in an Arcjet Plasma Expanding Through a Conical Nozzle

A diamond-shaped shock wave was created in a helium arcjet plasma. Visi- ble/ultraviolet emission spectroscopy was used to investigate the condition for the formation of stable shocks and to determine characteristics of the plasma. Dependence of the position of the shock front on the gas pressure in the expansion region was investigated. It was found that the shock wave arises from the collision of plasma particles and residual neutral atoms in that region. Continuum and line spectra of neutral helium were measured, from which the electron temper- atures were derived. The electron density was deduced from the Inglis-Teller limit of the He I 2p 3 P-3d 3 D series. The temperature and density were found to have almost constant values of 0.2 eV and 8.5×10 13 cm 3 , respectively, across the shock front.     

Electron transport behaviors across single grain boundaries in <Emphasis Type="Italic">n</Emphasis>-type BaTiO<Subscript>3</Subscript>, SrTiO<Subscript>3</Subscript> and ZnO

In some electroceramic materials, their unique electrical properties are due to potential barriers, i.e., double Schottky barriers (DSBs), formed at grain boundaries. So far, some researchers have revealed that the electrical properties of DSB are closely related to grain boundary characters, especially grain boundary coherency. For example, highly coherent boundary does not give PTCR or varistic property, while random types exhibit clear resistivity jump or abrupt current increment. Therefore, a concept of grain boundary design will be required for future device manufacturing, even in bulk materials. But it has not been clarified yet why the electron transport behaviors depend on them. In order to address this question, it is necessary to carry out a systematic experiment focusing on single grain boundaries using well-defined bicrystals.In the present study, we have summarized our studies with a special interest in electron transport behavior across single grain boundaries for n-type BaTiO₃, SrTiO₃ and ZnO.     

Emulsifying Properties of Bovine Blood Globin: A Comparison with Some Proteins and Their Improvement

The emulsifying properties of bovine blood globin were compared with those of bovine serum albumin, hemoglobin and ovalbumin. Although the emulsifying activity of globin was greater than that of hemoglobin and ovalbumin, it decreased in the isoelectric zone owing to the low solubility of globin. Acetylation increased the emulsifying activity of globin in the isoelectric zone, but decreased in the acidic pH region. Pepsin digestion did not increase the emulsifying activity of globin, but addition of CMC to pepsin-digested globin improved both its emulsifying activity and the emulsion stability.     

建筑与结构设计之"合"——石上纯也与佐藤淳的合作访谈

现代建筑发展潮流中,日本建筑的设计风格独树一帜,新生代建筑师层出不穷,这离不开其独特的建筑文化环境,比如师承体系,与结构师之间的紧密合作等.此次访谈以建筑师与结构师的合作为主题,采访了石上纯也和佐藤淳两位先生,以了解和学习他们的工作模式.本文包括三部分:第一部分探讨合作模式,通过初期项目的讨论,阐述了双方合作开始的契机与发展,而海外项目中与当地事务所合作经验的对比,更显示出他们合作模式的独特性;第二部分探讨设计理念,通过两位老师在以往展览和建筑设计项目中关于自然的讨论,对场地的回应等,表达出他们彼此对建筑和结构设计理念的理解与思考;第三部分探讨对未来教育模式、新材料、新技术的建议与展望.     

Effects of docosahexaenoic acid or arachidonic acid supplementation on the behavior of cardiomyocytes derived from human pluripotent stem cells

Background: Human heart changes its energetic substrates from lactate and glucose to fatty acids during the neonatal period. Noticing the lack of fatty acids in media for the culture of cardiomyocytes derived from human pluripotent stem cells (hiPS-CM), researchers have supplemented mixtures of fatty acids to hiPS-CM and reported the enhancement in the maturation of hiPS-CM. In our previous studies, we separately supplemented two polyunsaturated fatty acids (PUFAs), docosahexaenoic acid (DHA) or arachidonic acid (AA), to rat fetal cardiomyocytes and found that the supplementations upregulated the expressions of mRNAs for cardiomyocyte differentiation, fatty acid metabolism, and cellular adhesion. The enhancement in cellular contractility was attributed to the improvement in intercellular connection rather than a direct enhancement of the contractile force. Methods: This study reports the successive results of the effects of DHA or AA supplementation on hiPS-CM. In addition to the contractile force and mRNA measurements used in the previous study, we further investigated the effect of different cellular aggregations on the contractile force output by means of finite element analysis, measured glucose and fatty acids metabolites, and assessed cTNT and MLC2v expressions through immunofluorecsence evaluation. Results: It showed that the sole supplementation of albumin-conjugated DHA or AA can be taken up by hiPS-CM without other uptake-enhancing factors, and the supplementations may activate the CD36_­ERRγ metabolic pathway. DHA or AA supplementation increased the cellular contractile ratio on collagen gels and AA supplementation stimulated hiPS-CM aggregation to form cellular clusters. The enhancement effect on the hiPS-CM contractile force was modest since the increase in contractile force was not significant. AA supplementation was more effective than DHA supplementation because it significantly upregulated mRNA expressions of P300 and CD36. However, finite element analysis showed that the formation of clusters on a collagen gel attenuated the contractile force exerted by the gel on its surroundings. Conclusion: DHA and AA, as having been supplemented in infant formulas, have no direct and significant enhancement effect on the performance of the hiPS-CM when they were supplemented individually, although they were able to enter the cellular metabolic system. The AA supplementation showed some auxiliary effect on the maturation of hiPS-CM, which is worthy of further investigation under the consideration of membrane composition alteration and remodeling of membrane molecules.