一类一维p-Laplacian非线性奇异三点边值问题正解的存在性

利用Leray-Schauder非线性抉择定理和锥不动点定理证明一类一维非线性奇异p-Laplacian三点边值问题{(Φ(u′))′+q(t)f(u(t))=0,0t1,u(0)=0,u(1)=αu(η),0η1,0α1存在一个正解u∈C[0,1]∩C1(0,1],在(0,1]上u0,其中Φ(s)=s p-2s,p1,允许q(t)在t=0有奇性,并且非线性项f在u=0处具有奇性.     

Assignment of Soret MLCT band of reduced form of copper binuclear cluster in cytochrome c oxidase film

Low concentration of dithionite results in the reduction of Cu-Cn binuclear and heine a active sites of the cytochrome c oxidase thin solid film immersed in the acidic phosphate buffer, but Fe-Cu binuclear center keeps in the oxidation state. It manifests as a negative peak at 426 nm and a positive one at -408 nln in the difference spectra induced by dithionite. The former implies decrease of the oxidized form of heme a center, that is, Fea^3 →Fea^2 . And the latter results from the contribution of metal-ligand charge transfer (MLCT) transition in the reduced binuclear Cu-Cu cluster, rather than from that of heine a center. This stronger Soret MLCT band must be helpful to overcoming the difficulty in distinguishing the weaker copper sign from the stronger one of iron when studying copper-iron protein.     

The superoxide-generating NADPH oxidase: structural aspects and activation mechanism

Flavocytochrome b ₅₅₈ is the catalytic core of the respiratory-burst oxidase, an enzyme complex that catalyzes the NADPH-dependent reduction of O₂ into the superoxide anion O₂ ^- in phagocytic cells. Flavocytochrome b ₅₅₈ is anchored in the plasma membrane. It is a heterodimer that consists of a large glycoprotein gp91phox (phox for phagocyte oxidase) (β subunit) and a small protein p22phox (α subunit). The other components of the respiratory-burst oxidase are water-soluble proteins of cytosolic origin, namely p67phox, p47phox, p40phox and Rac. Upon cell stimulation, they assemble with the membrane-bound flavocytochrome b ₅₅₈ which becomes activated and generates O₂ ^-. A defect in any of the genes encoding gp91phox, p22phox, p67phox or p47phox results in chronic granulomatous disease, a genetic disorder characterized by severe and recurrent infections, illustrating the role of O₂ ^- and the derived metabolites H₂O₂ and HOCl in host defense against invading microorganisms. The electron carriers, FAD and hemes b, and the binding site for NADPH are confined to the gp91phox subunit of flavocytochrome b ₅₅₈ . The p22phox subunit serves as a docking site for the cytosolic phox proteins. This review provides an overview of current knowledge on the structural organization of the O₂ ^--generating flavocytochrome b ₅₅₈ , its kinetics, its mechanism of activation and the regulation of its biosynthesis. Homologues of gp91phox, called Nox and Duox, are present in a large variety of non-phagocytic cells. They exhibit modest O₂ ^--generating oxidase activity, and some act as proton channels. Their role in various aspects of signal transduction is currently under investigation and is briefly discussed. Received 28 May 2002; received after revision 20 June 2002; accepted 24 June 2002     

电聚合吡咯膜修饰的葡萄糖氧化酶电极

自制的铂丝电极经铂化处理后,将葡萄糖氧化酶与单体吡咯用循环伏安法共聚合到电极上,铂化后电极表面积的增大增加了固定的酶量,同时也增大了电极对Ｈ２Ｏ２的催化能力,使电极对葡萄糖的响应电流增大到７．５ｍＡ／（ｍｏｌ·Ｌ＾－１）,还测试了聚合液中酶浓度、ｐＨ值和聚合时间等因素对电极特性的影响。     

P*-型非线性互补问题解的存在性

首先利用Poincare‐Bohl定理给出择一性定理,然后用该定理证明非线性互补问题解的存在性,并获得互补问题有解的充分条件。     

橡椀单宁降解酶特性的研究

借助于没食子酸丙酯为模型化合物作为底物,对一株能抵抗橡椀单宁(鞣花类单宁)生物毒性并能有效降解这种单宁的菌株的降解特性进行了研究。结果表明这株菌不仅具有单宁酶的活性,而且具有多酚氧化酶（PPO）的活性。通过对不同底物对内胞霉PPO酶促反应速度的影响研究证实橡椀单宁的降解不仅与单宁酶有关还与多酚氧化酶有关。     

对日语文艺作品中另类文化表现的考察

日本近现代文学和影视作品中,有些文化元素由于表现形式异于常态,甚至是另类,有悖于传统文化柔美顺和的基调,经常被冠以变态、恐怖、残酷、畸形等称呼。这些文化元素具有审美主义、性爱取向、生死观三个方面的文化根源。     

Zn^2＋与苹果多酚氧化酶相互作用研究

为探讨苹果多酚氧化酶（简称PPO）的结构与功能关系,应用紫外差示光谱、同步荧光光谱及圆二色性光谱（CD）等生物物理技术和酶活性测定研究了外加Zn^2＋对苹果PPO的分子构象和酶活性的影响。结果表明,微景锌的加入能增加酶的活性和提高α-螺旋含量,当[Zn^2＋]／[PPO]为2．0左右时,苹果PPO活性最高,继续增加[Zn^2＋]／[PPO]比值,酶活性开始下降,比值为2．7以后,Zn^2＋表现了对PPO活性的抑制,α-螺旋含量下降;Zn（Ⅱ）可能与PPO中的组氨酸残基进行了配位,（ImH）σN＋σN→Zn^2＋、（ImH）σ→Zn^2＋、（ImH）π1→Zn^2＋、（ImH）Ⅱπ→Zn^2＋分别为227,241,265,335（nm）;色氨酸和酪氨酸的荧光均受到Zn^2＋的猝灭,但它们的微环境在Zn（Ⅱ）-PPO的相互作用中基本保持不变。     

提高磁钢电火花线切割加工速度的实验研究

采用一般的脉冲电源对磁钢进行电火花线切割加工,不可避免地将引起充磁,造成排屑困难。本文介绍了一种交变电流的脉冲电源,可以减少对磁钢的充磁效应,并通过实验得出了反向脉宽和反向电流的最佳值。     

高粱BTx623幼苗多酚氧化酶Real-time PCR引物扩增效率的检测

介绍了一种检测实时荧光定量PCR技术引物扩增效率的方法,以期为进一步应用实时荧光定量PCR奠定基础。同时通过实时荧光定量PCR技术,研究高粱BTx623幼苗中的多酚氧化酶基因SbPPO的表达情况,结果发现SbPPO2,SbPPO5,SbPPO6的相对表达量较高,这3个SbPPO可能在高粱BTx623幼苗中起到重要功能。