一维和二维多势阱能谱的Bsplines计算

用Bsplines函数基计算了一维多势阱和二维Henon Heiles势的能谱,得到了精度较高的结果.将这一结果与采用高斯基函数计算的结果进行比较,结果表明:Bsplines函数基用于研究一维束缚态问题比高斯函数基方法更方便,具有灵活、可塑性强、效率高等优点,适用于不同形式势作用下的系统的变分求解.     

Reaction mechanisms between methylamine and a few Schiff bases: Ab initio potential energy surfaces of a catalytic step in semicarbazide sensitive amino oxidases (SSAO)

The potential energy surfaces for the transamination reaction catalyzed by SSAO were explored for some of the possible reactants considered in a preliminary investigation (Comput Chem 2000, 24 , 311). The proton transfer to methylamine (as a model of the catalytic base belonging to the enzyme active site)—either from the keto or enol form of the reactant Schiff bases with one of the possible cofactors, pyridoxal phosphate, PLP (using as a model the pyridoxal ring protonated at N)—was investigated. The enol form seems to be preferred in the region of the neutral intermediate, because even the keto form undergoes a spontaneous rearrangement to the enol form once the C_α proton is delivered to methylamine, producing methylammonium. When the proton is returned back to the Schiff base (on C₁), the adduct is about 1.4 kcal/mol more stable than the reactants, while a canonical electron distribution is obtainable only for the enol form. The proton transfer to methylamine was also studied in the presence of the other possible cofactor (para or ortho) topaquinone, TQ. A steep uphill pathway, similar to the keto‐pyridoxal Schiff base one, is obtained using the Schiff base with pTQ, which requires a rearrangement to the final intermediate. On the contrary, using the oTQ structures with the quinonoid O on the same side of methylamine, the proton abstracted from the Schiff base goes spontaneously onto the other quinonoid oxygen. The effect on the barrier heights produced by the presence of a variety of functional groups in the vicinity of the pyridoxal ring nitrogen was also examined. © 2001 John Wiley & Sons, Inc. Int J Quant Chem, 2001     

Synthesis of Calix[4]resorcinarene Schiff Bases

Introduction Calix[4]resorcinarenes are cyclic tetramers in which four resorcinol units are linked via alkylmethylene bridges in the o-position to each resorcinic hydroxyl group[1]. Their structures resemble that of p-butylcalix[n]arenes and render them of interest as host compounds in many contemporary fields of supramolecular chemistry.     

Number of graphene layers exhibiting an influence on oxidation of DNA bases: Analytical parameters

This article investigates the analytical performance of double-, few- and multi-layer graphene upon oxidation of adenine and guanine. We observed that the sensitivity of differential pulse voltammetric response of guanine and adenine is significantly higher at few-layer graphene surface than single-layer graphene. We use glassy carbon electrode as substrate coated with graphenes. Our findings shall have profound influence on construction of graphene based genosensors.     

The Detection of Native Fluorescence in Peroxidized Fatty-Acids

Abstract

Peroxidized unsaturated fatty-acids show fluorescent properties in the absence of amino groups. Compounds formed from linolenic acid autooxidized for 5 days have been separated on thin-layer chromatograms with paired zero-time controls then located by their thiobarbituric acid and peroxidase reactivity. Spectrofluorimetric analysis of the eluted 5-day zones showed that two had ultraviolet fluorescence and a third visible fluorescence.     

Characterization of Solid Cones

The author gives a dual characterization of solid cones in locally convex spaces. From this the author obtains some criteria for judging convex cones to be solid in various kinds of locally convex spaces. Using a general expression of the interior of a solid cone, the author obtains a number of necessary and sufficient conditions for convex cones to be solid in the framework of Banach spaces. In particular, the author gives a dual relationship between solid cones and generalized sharp cones. The related known results are improved and extended.     

Zinc(II) complexes with Schiff bases derived from ethylenediamine and salicylaldehyde: the synthesis and photoluminescent properties

The effect of the nature of organic ligands and complex formation on the photoluminescent characteristics (relative quantum yield, excited-state lifetime) and thermal stability of tetradentate Schiff bases (H₂L), derivatives of salicylaldehyde (H₂(SAL)¹, H₂(SAL)²), o-vanillin (H₂(MO)¹, H₂(MO)²) with ethylenediamine and o-phenylenediamine, and their zinc(II) complexes was studied. Zinc(II) complexes were synthesized by the reaction of H₂L with Zn(AcO)₂·2H₂O in MeOH at room temperature or under reflux. In the case of H₂L = H₂(SAL)², H₂(MO)¹, H₂(MO)², complexes of the composition ZnL·H₂O were isolated irrespective of the temperature. For H₂L = H₂(SAL)¹, the reaction results in Zn(SAL)¹·H₂O at room temperature and in anhydrous dimeric complex [Zn(SAL)¹]₂ under reflux. Density functional calculations of H₂L and ZnL confirmed that (1) luminescence of these compounds is due to the π-π* transition between orbitals of the organic ligand and (2) enhancement of conjugation of the chain and introduction of electron-donating substituents lead to a decrease of the energy gap and, there-fore, to a bathochromic shift of the emission maximum. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1846–1855, September, 2008.     

Thermally latent synthesis of networked polymers from multifunctional hemiacetal ester and diepoxide catalyzed by Schiff‐base‐zinc chloride complex

Thermally latent reaction of a copolymer ( P1 ) bearing hemiacetal ester and n‐butyl methacrylate moieties and glycidyl phenyl ether ( 2 ) was catalyzed by bis(p‐methoxybenzylidene)‐1,2‐diiminoethane/zinc chloride complex (ZnCl₂/ 3 ) at 30–150 °C for 6 h. No reaction of P1 and 2 took place below 70 °C, and it smoothly proceeded above 120 °C. The latencies and activities mean that ZnCl₂/ 3 meets both the high latencies at ambient conditions and the high activities at desired temperatures. Thermal crosslinking reaction employing multifunctional derivatives was carried out using ZnCl₂/ 3 at 140 °C for 6 h to afford a networked polymer in high yields. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3682–3689, 2008     

NON-COMMUTATIVE GRÖBNER BASES UNDER COMPOSITION

Polynomial composition is the operation of replacing the variables in a polynomial with other polynomials. In this paper we give sufficient and necessary conditions on a set Θ of non-commutative polynomials to assure that the set G ○ Θ of composed polynomials is a Gröbner basis in the free associative algebra whenever G is. The subject was initiated by Hong, treating the commutative analogue in (1998, J. Symb. Comput. 25, 643–663).