Astrophysical S-factors from asymptotic normalization coefficients

S-factors for direct capture reactions can be found at astrophysical energies from asymptotic normalization coefficients which provide the normalization of the tail of the overlap function. For example the overlap for ⁸B → ⁷Be+p defines the S-factor for ⁷Be (p, γ)⁸B. Peripheral transfer reactions offer a technique to determine these asymptotic normalization coefficients. As a test of the technique, the ¹⁶O(³He, d)¹⁷F reaction has been used to determine asymptotic normalization coefficients for transitions to the ground and first excited states of ¹⁷F. The S-factors for ¹⁶O(p, γ)¹⁷F calculated from these ¹⁷F → ¹⁶O+p asymptotic normalization coefficients are found to be in very good agreement with recent measurements. Following the same technique, the ¹⁰B(⁷Be, ⁸B)⁹Be and ¹⁴N(⁷Be, ⁸B)¹³C reactions have been used to measure the asymptotic normalization coefficient for ⁷Be(p, γ)⁸B. This result provides an indirect determination of S ₁₇(0).     

A Concise Review of Current In Vitro Chemical and Cell-Based Antioxidant Assay Methods

Antioxidants remain interesting molecules of choice for suppression of the toxic effects of free radicals in foods and human systems. The current practice involves the use of mainly synthetic molecules as potent antioxidant agents. However, due to the potential negative impact on human health, there is an intensive effort within the research community to develop natural alternatives with similar antioxidant efficacy but without the negative side effects of synthetic molecules. Still, the successful development of new molecules depends on the use of reliable chemical or cell culture assays to screen antioxidant properties. Chemical antioxidant assays include the determination of scavenging ability against free radicals such as DPPH, superoxide anion radicals, hydroxyl radicals, hydrogen peroxide, and nitric oxide. Other antioxidant tests include the ability of compounds to bind and sequester prooxidant metal cations, reduce ferric iron, and attenuate the rate of lipid oxidation. Ex vivo tests utilize cell cultures to confirm entry of the molecules into cells and the ability to quench synthetic intracellular free radicals or to stimulate the increased biosynthesis of endogenous antioxidants. In order to assist researchers in their choice of antioxidant evaluation methods, this review presents background scientific information on some of the most commonly used antioxidant assays with a comparative discussion of the relevance of published literature data to food science and human nutrition applications.     

多谱线耦合系统辐射束缚问题的理论处理

提出一种处理多荧光谱线耦合系统辐射束缚问题的理论方法．这里的耦合包括激发态间的碰撞传能和当谱线重叠时对荧光的交叉吸收．首先将描述辐射束缚的Ｈｏｌｓｔｅｉｎ方程扩展为适用于描述多个激发能级且包括交叉耦合项的微分积分方程组，并将其纳入矢量、矩阵的形式．然后直接通过算符运算求解，给出按算符展开的级数解式．最后对级数解进行约化，导出一个只用有限项便可对系统行为进行完整描述的、远较简单截断近似优越的结果．还给出了一个双激发能级系统的计算实例     

Functional Characterization of Mung Bean Meal Protein-Derived Antioxidant Peptides

The aim of this work was to characterize the antioxidant properties of some of the peptides present in bromelain mung bean meal protein hydrolysate (MMPH). The MMPH was subjected to two rounds of bioassay-guided reversed-phase HPLC separation followed by peptide identification in the most potent fractions using tandem mass spectrometry. Twelve antioxidant peptides, namely, HC, CGN, LAN, CTN, LAF, CSGD, MMGW, QFAAD, ERF, EYW, FLQL, and QFAW were identified and assayed for antioxidant properties. CTN, HC, CGN, and CSGD were the most potent (p < 0.05) DPPH radical scavengers with EC₅₀ values of 0.30, 0.29, 0.28, and 0.30 mg/mL, respectively, which are lower than the 0.03 mg/mL obtained for reduced glutathione (GSH). CTN, HC, CGN, and CSGD exhibited the most potent (p < 0.05) scavenging activities against hydroxyl and superoxide radicals with EC₅₀ values that are similar to those of GSH. The cysteine-containing peptides also had stronger ferric reducing antioxidant power and metal chelation activity than peptides devoid of cysteine. In contrast, MMGW, ERF, and EYW had poor radical scavenging and metal chelation activities. We conclude that the availability of the sulfhydryl group may have enhanced antioxidant potency while the presence of bulky groups such phenylalanine and tryptophan had an opposite effect.     

Determination of nutritional and bioactive properties of peptides in enzymatic pea, chickpea, and mung bean protein hydrolysates

Within the primary structure of many pea and mung bean proteins are peptide sequences that can potentially be used in the formulation of therapeutic products for the treatment and prevention of human diseases. However, these peptide sequences need protease treatments before they can be released free of the parent proteins. Unlike chemical hydrolysis, enzymatic treatment enables more efficient tailoring of peptide products without formation of toxic by-products or destruction of amino acids. This review provides information on current methods that have been used to convert inactive pea and mung bean proteins into bioactive peptides. It focuses on 3 main bioactive properties, such as inhibitions of (1) angiotensin converting enzyme (ACE) activity; (2) calmodulin (CaM)-dependent enzymes; and (3) copper-chelating activity. ACE is an established marker for hypertension, high levels of some CaM-dependent enzymes are risk factors for various human diseases including cancer and Alzheimer's disease, and high vascular copper concentrations may potentiate atherosclerosis. Also reviewed are the production and evaluation of activity of hypoallergenic peptides that may offer protection against anaphylactic reactions. The 3 main proteins discussed are chickpea, mung bean, and field pea.     

Error Bounds for Hermite Interpolation by Quadratic Splines on an {alpha}-Triangulation

For l, an -triangulation F of a planar domain is such that,for every T F, there holds 1 R_T/2r_T , where R_T (resp. r_T)denotes the radius of the circumscribed (resp. inscribed) circleof the triangle T. When T is varying in F the centre of itsinscribed circle is varying in a compact interior to T and itsorthogonal projections on the sides are varying in compact intervalsinterior to these sides. Precise results are given about thesizes of these compacts and are used for the computation oferror constants in the problem of Hermite interpolation by Powell-Sabinquadratic finite elements, bringing to the fore their dependenceon the parameter .     

Competitive adsorption between egg yolk lipoproteins and whey proteins on oil-in-water interfaces

Adsorption characteristics of mixtures of egg yolk lipoproteins and whey protein isolate (WPI) were studied in emulsions (20% oil, v/v 0.5% protein, w/v pH 7.0) made with pure triolein or n-tetradecane. Emulsions stabilized by granule lipoproteins (GLP) or low-density lipoproteins (LDL) had smaller particle sizes than emulsions stabilized by WPI. In protein mixtures containing egg yolk lipoproteins and WPI, there was a decrease in particle size with increased concentration of the yolk lipoproteins. The reduction in particle size of emulsions was greater when WPI was mixed with LDL than with GLP, for both n-tetradecane and triolein. Emulsions made with triolein had smaller particle sizes than those made with n-tetradecane, irrespective of the type or ratio of lipoproteins used. Therefore, the protein concentration per unit area of the interface was greater for emulsions containing n-tetradecane than for triolein. In displacement experiments, emulsions made with only WPI were mixed with 0.1 and 0.5% GLP or LDL for a given period of time and the relative concentrations of β-lactoglobulin and -lactalbumin determined. Displacement of β-lactoglobulin by LDL increased with time and was greater in emulsions made with n-tetradecane than with triolein. However, displacement of β-lactoglobulin by GLP was greater in emulsions made with triolein than with n-tetradecane. -lactalbumin was completely displaced from the interface within 1 min of addition of either 0.5% GLP or LDL, whereas addition of 0.1% GLP or LDL resulted only in a partial displacement. The results suggest that egg yolk lipoproteins are more surface active than WPI and that LDL penetrates the n-tetradecane–water interface more than GLP, while GLP penetrates the triolein–water interface more than LDL.     

肉苁蓉精油化学成分的研究

肉苁蓉 Cistanche Salsa(C.A.Mey.)G.Beak 是列当科 Orobanchaceae 植物肉苁蓉的肉质茎;又名大芸,纵蓉。它分布在北疆地区荒漠戈壁地带,有益肾壮阳,延年益寿等功能,故有“沙漠人参”之称。肉苁蓉是一种常用的中药,新疆地区资源丰富,其精油化学成分在国内外未见报道。为了整理和发掘祖国医药学宝库,我们对其化学成分进行了研究。