Immunochemical Properties of Proteins Glycosylated Through Maillard Reaction: β-Lactoglobulin-Lactose and Ovalbumin-Glucose Systems

β-Lactoglobulin and ovalbumin were glycosylated through Maillard reaction with glucose and lactose, respectively. The immunoreactivity between β-lactoglobulin-lactose and its specific antibody was inhibited strongly by free galactose and lactose, whereas free glucose did not at all inhibit the reaction between ovalbumin-glucose and its specific antibody. Furthermore, the antibody directed against β-lactoglobulin-lactose reacted also with other lactosylated proteins but the antibody to ovalbumin-glucose had no reactivity with the other proteins glycosylated with glucose, indicating that lactose attached to carrier proteins through Maillard reaction could be a hapten-like antigen but glucose could not.     

Determination of Emulsifying Properties of Some Proteins by Conductivity Measurements

A method was developed to measure the emulsifying activity and emulsion stability of proteins using a simple apparatus consisting of a glass column with a conductivity cell. A significant correlation was observed between the emulsifying activity and emulsion stability of 10 proteins determined by the conductivity method examined in this paper and the turbidity method of Pearce and Kinsella (1978). These results suggest that the emulsifying properties can be estimated by measuring changes in the conductivity of emulsion. The advantages of the conductivity method are to measure accurately and simply the emulsifying properties of proteins, because this method directly and automatically measures changes in the physical constant (that is, conductivity) of emulsion.     

Heat-Induced Changes in Free Amino Acids on Manufacturing Heated Pulps, Purées and Pastes from Tomatoes

The effect of heating on the free amino acid composition of processed tomato products, heated pulps, purées and pastes was examined. The major components of the fresh pulp were glutamic acid, γ-aminobutyric acid, aspartic acid, glutamine and asparagine. The heating process caused about a 40% loss of the total amino acids, which was attributable mostly to decreases in glutamic acid, glutamine and aspartic acid. Neither aromatic amino acids nor basic amino acids decreased in this process. Additional low temperature heating applied to the heated pulp to manufacture purées and pastes caused less effects than the high temperature heating used to prepare the pulp.     

Survey of Rabbit Skeletal Muscle Peptidases Active at Neutral pH Regions

A survey of oligopeptide hydrolases active at neutral pH regions responsible for increased free ammo acids on aging of high ultimate pH muscles were performed examining chromatographic behavior and substrate specificity of rabbit skeletal muscle extract. The DEAE-cellulose chromatography of muscle extract revealed five major activity peaks respectively ascribable to a dipeptidase, an aminotripeptidase, an ammopeptidase, leucine aminopeptidase and the 160,000 dalton-aminopeptidase purified previously by us. Since the 160,000 dahon-ammopeptidase showed a broader substrate specificity than the two other aminopeptidases, it is most likely that this enzyme shares the largest part in the tetrapeptide hydrolysis in rabbit skeletal muscle at neutral pH regions.     

地下车库颗粒受限扩散下的凝并特性

为研究车辆排放颗粒在地下车库内凝并率的分布规律及其对颗粒受限扩散的影响程度.根据颗粒物扩散和凝并理论,采用Realizable k-ε模型模拟空气流场分布特性,并结合数值模拟中的场函数方法将颗粒凝并和扩散过程相结合,分析地下车库不同数量车辆在受限扩散条件下颗粒半衰时间的变化和粒径变化.结果表明:在排气管附近,颗粒半衰时间最短,凝并作用最强.在沿高度方向2 m以下的区域内,当启动车辆数不多于2台时,颗粒半衰时间随高度线性下降,当启动车辆数不少于4台时,半衰时间随高度呈对数下降.凝并作用对中间段和大粒径段粒子数浓度的变化影响更大,颗粒呈现出由小变大的粒径变化趋势.启动车辆数越多,凝并导致的粒径分布不均匀性越明显.     

Stability of ZrO2 Phases in Ultrafine ZrO2-Al2O3 Mixtures

Mixtures of ultrafine monoclinic zirconia and aluminum hydroxide were prepared by adding NH₄OH to hydrolyzed zirconia sols containing varied amounts of aluminum sulfate. The mixtures were heat-treated at 500° to 1300°C. The relative stability of monoclinic and tetragonal ZrO₂ in these ultrafine particles was studied by X-ray diffractometry. Growth of ZrO₂ crystallites at elevated temperatures was strongly inhibited by Al₂O₃ derived from aluminum hydroxide. The monoclinic-to-tetragonal phase transformation temperature was lowered to ∼500°C in the mixture containing 10 vol% Al₂O₃, and the tetragonal phase was retained on cooling to room temperature. This behavior may be explained on the basis of Garvie's hypothesis that the surface free energy of tetragonal ZrO₂ is lower than that of the monoclinic form. With increasing A1₂O₃ content, however, the transformation temperature gradually increased, although the growth of ZrO₂ particles was inhibited; this was found to be affected by water vapor formed from aluminum hydroxide on heating. The presence of atmospheric water vapor elevates the transformation temperature for ultrafine ZrO₂. The reverse tetragonal-to-monoclinic transformation is promoted by water vapor at lower temperatures. Accordingly, it was concluded that the monoclinic phase in fine ZrO₂ particles was stabilized by the presence of water vapor, which probably decreases the surface energy.     

Relationship between an increased serum kynurenine/tryptophan ratio and atherosclerotic parameters in hemodialysis patients

Essential amino acid tryptophan (Trp) is mainly catabolized by indoleamine 2,3‐dioxygenase, which leads to the formation of kynurenine (Kyn). In this study, we reexamined whether an increased indoleamine 2,3‐dioxygenase activity, as estimated by the Kyn/Trp ratio (μM/mM), is associated with atherosclerotic parameters in hemodialysis (HD) patients. Serum Trp and Kyn were measured in 243 HD patients by liquid chromatography/electrospray ionization tandem mass spectrometry. We measured carotid artery intima‐medial thickness, brachial‐ankle pulse wave velocity, ankle‐brachial pressure index, and the cardio‐ankle vascular index. Log‐transformed Kyn/Trp ratio was significantly correlated with log‐transformed time on HD (ρ=0.28, P<0.01), log‐transformed highly sensitive C‐reactive protein (ρ=0.20, P<0.01), and peripheral total lymphocyte count (ρ=?0.13, P<0.05). A significant association was found between log‐transformed Kyn/Trp ratio and mean carotid artery intima‐medial thickness (ρ=0.18, P<0.01). Mean carotid artery intima‐medial thickness was significantly higher in the lowest quartile of Kyn/Trp ratio (<165) (0.62±0.12 mm) when compared with the highest quartile (≥304) (0.68±0.15 mm) (P<0.01). Ankle‐brachial pressure index was lower in the second quartile (1.01±0.20), the third quartile (1.01±0.19), and the fourth quartile (1.03±0.15) compared with that in the first quartile (1.09±0.13) (P<0.05). It follows from these findings that the Kyn/Trp ratio increases with time on HD, and is associated with advanced atherosclerotic changes in chronic HD patients.     

耐热型碱显影感光树脂的合成及性能研究

选用羟基封端的聚酰亚胺为耐热链段，将其与双羟甲基丙酸(DMPA)和异氟尔酮二异氰酸酯(IPDI)反应，制备了异氰基团封端的聚酰亚胺。进一步使用得到的产物与甲基丙烯酸羟乙酯(HEMA)反应，制备了含氨酯-丙烯酸酯的聚酰亚胺树脂。通过对聚酰亚胺的羟基封端的方式的改变，研究了对最终树脂热稳定性的影响。实验结果表明聚酰亚胺结构的引入能够改善树脂的热稳定性，尤其是芳基取代时对热稳定性的提高最为明显。     

Judging Degradation of Lithium‐Ion Batteries Using a Real‐Time Capacitance Measurement

A novel method was proposed to judge degradation/health of lithium‐ion batteries (LIBs) using the capacitance that was estimated from the real‐time voltage and current characteristics of the batteries. It is thought that the capacitance of LIBs decreases with degradation because of undesirable components formed on the electrodes that are the main cause of the degradation. As the LIBs are active, the capacitance was evaluated from the differential equation, ?Q /?v = I /(?v /?t ) = i /(dv /dt ), using the voltage and current characteristics during the charging or discharging. The capacitances of the commercial LIBs with different SOHs; 100%, 92%, and 88% were estimated during the charging and discharging using the equation. The average capacitance in the specific voltage region of the batteries was directly proportional to the state of health. Therefore, the proposed measurement is thought to be a useful method for judging degradation of LIBs.     

ANTIMICROBIAL ACTIVITY OF FATTY ACIDS AND THEIR ESTERS AGAINST A FILM-FORMING YEAST IN SOY SAUCE

Antimicrobial activity of fatty acids and their glycerol and sugar esters against a film-forming yeast isolated from raw soy sauce was determined in diluted soy sauce. In a series of fatty acids (alkyl chain length of 7, 9, 11 and 13) and their monglycerides, capric acid and monolaurin had the highest inhibitory activity. Two selected sugar esters (sucrose monocaprate and sucrose monolaurate) could not completely inhibit the growth of test organism throughout 3 weeks.