Fast patterning and dry-etch of SiNχ for high resolution nanoimprint templates

We developed a simplified nanofabrication process for imprint templates by fast speed electron beam lithography (EBL) and a dry etch technique on a SiNx substrate, intended for large area manufacturing. To this end,the highly sensitive chemically amplified resist (CAR), NEB-22, with negative tone was used. The EBL process first defines the template pattern in NEB-22, which is then directly used as an etching mask in the subsequent reactive ion etching (RIE) on the SiNx to form the desired templates. The properties of both e-beam lithography and dry etch of NEB-22 were carefully studied, indicating significant advantages of this process with some drawbacks compared to when Cr was used as an etching mask. Nevertheless, our results open up a good opportunity to fabricate high resolution imprint templates with the prospect of wafer scale manufacturing.     

Chemical comparison of coat and kernel of mung bean by nuclear magnetic resonance-based metabolic fingerprinting approach

To utilize the wasted coat resources, which are usually discarded in the process of mung bean derived food, and understand the traditional use of mung bean, nuclear magnetic resonance-based metabolic fingerprinting approach was used to compare the chemical composition between the coat and kernel. The results showed that the flavonoids, isovitexin and vitexin, were only present in the coat, while the kernel contained higher levels of amino acids and sugars. In addition, the coat showed much stronger 2,2-diphenyl-1-picrylhydrazyl scavenging activity than the kernel, which was in accordance with the analysis result from the biplot of partial least squares.     

Influence of ultrasound treatment on the physicochemical and antioxidant properties of mung bean protein hydrolysate

This study aimed to investigate influence of ultrasonic treatment on physicochemical and antioxidant properties of mung bean protein hydrolysate (MPH). Physicochemical properties of MPH were evaluated by Tricine-SDS-PAGE, particle size distribution, fourier transform infrared spectroscopy (FTIR) and fluorescence spectroscopy, among others. Radicals scavenging activities of ABTS, hydroxyl, superoxide anion, Fe²⁺ chelating ability and reducing power characterized antioxidant activities of MPH. MPH contained four bands of 25.6, 12.8, 10.6 and 4.9 kDa, in which 4.9 kDa was the most abundant. Ultrasonic treatment increased the contents of aromatic and hydrophobic amino acids in MPH. Ultrasonic treatment decreased the content of α-helix of MPH and increased β-sheet and β-turn compared to MPH. MPH-546 W (ultrasonic treatment 546 W, 20 min) had the lowest average particle size (290.13 nm), zeta potential (-36.37 mV) and surface hydrophobicity (367.95 A.U.). Antioxidant activities of ultrasonicated-MPH increased with the ultrasonic power, achieving the lowest IC₅₀ (mg/mL) of 0.1087 (ABTS), 1.796 (hydroxyl), 1.003 (superoxide anion) and 0.185 (Fe²⁺ chelating ability) in 546 W power. These results indicated ultrasonic treatment would be a promising method to improve the antioxidant properties of MPH, which would broaden the application scope of MPH as bioactive components in the food industry.     

La relation structure chimique–propriétés physiques des galactomannanes extraits de la caroube

Carob galactomannan fine chemical structure is closely related to the physical behavior developed in aqueous solution. Three elements of structural characterization are mainly described in the literature: the degree of galactose substitution, chain length, and galactose units distribution. This review article will attempt to highlight the impact of different structural features on physical properties such as solubility, viscosity, formation of hydrogels or gels in combination with other saccharides. The impact of industrial purification process on the structure and physical properties is also developed.     

蚕豆花精油化学成份的研究

用毛细管气相色谱-质谱-数据系统联用技术分析了蚕豆花精油的化学成份。已鉴定的十六个化学成份为芳樟醇、松油醇、4-甲氧苯基乙酮及其异构体、丁香酚及其异构体、2,6-二甲氧基-4-丙基-2-苯酚、十四碳烷酸、6,10,14-三甲基十五烷酮-2、十六碳烷酸、十七碳烷酸、十八碳三烯醛、十八碳二烯酸的异构体和十八碳烷酸。它们共占精油含量的90%左右。     

New insight into the mechanism of cellulose and callose biosynthesis: proteases may regulate callose biosynthesis upon wounding

Using a silver-enhanced, gold-secondary antibody immuno-location approach, we investigated the mechanisms for the switch from -1,4- to -1,3-glucan biosynthesis upon wounding. Antibodies against -1,4- and -1,3-glucan synthases were used to locate these synthases before and after wounding of Mung bean (Vigna radiata var Berken) hypocotyls. Within 5 min of wounding, -1,4-glucan synthases which were densely localized on plasma membranes adjacent to the secondary walls at the wound site completely disappeared, and -1,3-glucan synthases became labeled. The immuno-location of the -1,3-glucan synthases in the secondary walls was in good accordance with the region where the -1,4-glucan synthases were localized before wounding. Aniline blue was also utilized to visualize the deposition of callose upon wounding. Within 5 min of wounding, callose had accumulated in the corresponding region where the immuno-labeling of -1,3-glucan synthase was detected after wounding. The -1,3-glucan synthases were always detected from the sieve plate and plasmodesmata which are known to have constitutive synthesis of callose regardless of wounding. Secondary walls located distantly into the tissue away from the wound site were consistently labeled by the -1,4-glucan synthase antibody even after wounding. Immuno-blot analysis clearly shows that the levels of -1,4-glucan synthase subunit Ces A decreased dramatically within 30 min, whereas the -1,3-glucan synthase subunit CFL1 levels increased significantly after wounding. The intensity of labeling reached a maximum at the wound site, and gradually decreased in correspondence with the distance from the wound site. When a protease inhibitor cocktail was applied upon wounding, neither the -1,3-glucan synthase appeared nor callose was deposited during the first 5 min of wounding. On the other hand, -1,4-glucan synthase was detected at the wound site, implying that activation of -1,3-glucan synthase may rely on the degradation of the -1,4-glucan synthase. Our study may provide new insight into -glucan synthesis in higher plants.     

Phase transition of locust bean gum-, tara gum- and guar gum-water systems

Phase transition behaviour of neutral galactomannans, i.e., locust bean gum (LBG), tara gum (Tara-G) and guar gum (GG)-water systems is investigated. In this study, water content {W_c=(gram of water)/(gram of dry sample)} of these systems was varied from 0.2 to 3.6 g g^-1. In the DSC heating curves, glass transition (T_g), cold crystallization (T_cc) and melting (T_m) were observed in all three samples. In addition, liquid crystal transition (T*) was observed in GG-water systems at a temperature higher than Tm. Using T_g, T_cc, Tm and T*, phase diagrams of each system were established. From the melting enthalpy of ice in the systems, three types of water, non-freezing water (W_nf), freezing bound water (W_fb) and free water were calculated. The maximum amount of Wnf was observed at Wc=0.7 g g-1, where Tg showed the lowest temperature. The amount of Wnf in LBG and GG is higher than that of Tara-G, whereas the highest amount of Wfb is found in GG. T* was only observed in GG-water systems. It is concluded that frequency of the side chains in the repeating unit of the main chains of these three galactomannan affects the frozen structure of the glassy state in the presence of water. This revised version was published online in July 2006 with corrections to the Cover Date.     

二维多层PtRu/PtNd纳米薄膜的结构效应及电催化氧化活性

采用离子束多靶溅射技术控制膜层结构制备出二维多层PtRu/PtNd纳米合金薄膜作为微型直接甲醇燃料电池(DMFCs)阳极催化电极材料. 应用X射线光电子能谱(XPS)、原子力显微镜(AFM)、X射线衍射(XRD)、掠入射X射线衍射(GIXD)研究了薄膜表面的化学状态、形貌以及薄膜表层、次表层和体相的结构,并用CO-stripping伏安法、循环伏安法(CV)、线性扫描伏安法(LSV)、计时电流法(CA)等电化学方法测试薄膜催化剂的电化学活性比表面积及其对甲醇的电催化氧化. 结果表明, 多次交替沉积制备的PtRu/PtNd薄膜, 由于溅射产生的Pt+、Ru+和Pt+、Nd+之间的相互作用, 使薄膜表面的化学状态和膜层结构发生变化, 其衍射谱峰呈现异常宽化, Pt与Nd之间产生电子转移, 证实了PtRu/PtNd纳米合金薄膜是一种具有特殊膜层结构和电子结构的二维多层PtRu/PtNd纳米合金薄膜, 电化学活性比表面积高达115.00m2 ·g-1, 在酸性溶液中电催化氧化甲醇的活性显著提高.