A Note on the Prime Spectrums of Character Rings of Finite Groups

0Introduction LetGbeafinitegroupoforder|G|=g,andletR(G)denotethecharacterringofG,whichisgeneratedbyalltheirreduciblecomplexcharactersofG.LetZbetherationalintegerringandNthesetofnatural numbers,andletZ[ω]betheintegralextensiongeneratedbyaprimitiveg throotωofunity.SupposethatSisasubringof thealgebraicnumberfieldsuchthatZ[ω]S.πisasetofra tionalprimenumbersdefinedasfollowsπ={p｜pisarationalprimenumbersuchthatp-1S}.Definition1WecallthataconjugacyclassCofthefinite groupGisaπregularconju…     

The role of protein surface charges in ion binding

Protein engineering is a means of probing the role of electrostatic interactions in protein functions; this elegant technique has been applied to the elucidation of electrostatic effects in enzyme catalysis. Here we show how the use of mutant proteins allows the determination of the contributions of individual charges to the free energy of ion binding to proteins. We have investigated the importance of three negatively charged side chains in the binding of Ca2+ to bovine calbindin D9K (ref.2): these are clustered around the calcium sites but are not directly involved as ligands. Each of these charges is found to contribute approximately 7 kJ mol-1 to the free energy of binding of two Ca2+ ions and to affect the cooperativity of Ca2+ binding. The influence of surface charges on ion binding to proteins may be more common than generally supposed and could have important consequences for protein function.     

Quantum chemical studies on tuning the second-order nonlinear optical molecular switching of triarylborane derivatives

In this work, density functional theory (DFT) combined with the finite field (FF) method has been adopted to analyze the second-order nonlinear optical (NLO) properties of the triarylborane (TAB) derivatives obtained by introducing different inductive electron groups into the phenylene ring of the TAB (RTAB, where R=2-C6H5-C2B10H10(1),R=F(2), R=Me(3),R=NO2(4),R=NH2(5)). The static first hyperpolarizabilities (βtot) of the RTAB molecules can be switched by binding one F- to the boron center (RTAB′) or one-electron reduction (RTAB"). The DFT-FF calculations show that the βtot values of 2′, 3′ and 5′ decrease while those of 1′ and 4′ increase compared with the values of their neutral molecules, which was attributed to the fact that the charge transfers of 2, 3 and 5 become smaller and those of 1 and 4 become larger by binding one F- ion to the boron center, according to time-domain DFT (TD-DFT) analysis. However, the incorporation of one electron enhances the second-order NLO properties of the RTAB molecules remarkably, especially for system 1. It is notable that the βtot value of reduced form 1″ is 508.69×10-30 esu, i.e. about 578 times larger than that of system 1. Frontier molecular orbital (FMO) and natural bond orbital (NBO) analyses suggest that the reversal of the charge distribution between the neutral molecules and their reduced forms leads to low HOMO-LUMO energy gaps (E0) and thus large βtot values for the reduced forms.     

An Improved Genetic Algorithm for Problem of Genome Rearrangement

In view of the fact that the problem of sorting unsigned permutation by reversal is NP-hard, while the problem of sorting signed permutation by reversal can be solved easily, in this paper, we first transform an unsigned permutation of length n,π （π1 ,… ,πn）, into a set S（π） containing 2^n signed permutations, so that the reversal distance of π is equal to the reversal distance of the optimal signed permutation in S（π）. Then analyze the structural features of S（π） by creating a directed graph and induce a new computing model of this question. Finally, an improved genetic algorithm for solving the new model is proposed. Experimental results show that the proposed model and algorithm is very efficient in practice.     

Isotope effect of the stereodynamics in the reactions F+HCl→HF+Cl and F+DCl→DF+Cl

Using a new ground-state ab initio potential energy surface reported by Deskevich et al., the product polarizations in the reactions F+HCl→HF+Cl and F+DCl→DF+Cl were studied by employing the quasi-classical trajectory method. At a collision energy of 10 kcal/mol, the four generalized polarization-dependent differential cross-sections (2π/σ)(dσ₀₀/dω _t ), (2π/σ)(dσ₂₀/dω _t ), (2π/σ)(dσ₂₂₊/dω _t ) and (2π/σ)(dσ₂₁₋/dω _t ) were calculated in the center-of-mass frame. The distribution of the angle between k and j′, P(θ _r ), the distribution of the dihedral angle denoting the k-k′-j′ correlation, P(φ _r ), and the angular distribution of the product rotational vectors in the form of polar plots P(θ _r , φ _r ) were also calculated. The evident influence of isotope substitution on the product polarization is revealed. This effect may result from the different mass factors of the two reactions.     

Synthesis of L-cystine bridgedbis（β-cyclodextrin） and its cooperative binding toward guest molecules

A novel p-cyclodextrin derivative, L-cystine bridged bis(β-cyclodextrin) 1 has been synthesized and characterized by 1H NMR, 13C NMR, IR, Raman and combustion analyses. Spectrofluorometric titrations have been performed in aqueous phosphate buffer solution (pH=7.20) at 25℃ to give the complex stability constants (Ks) and Gibbs free energy changes (-△G°) for the stoichiometric 1 : 1 inclusion complexation of 1 with four dyes. The binding abilities and molecular selectivities are discussed from the viewpoint of size/shape-fit and electrostatic interactions between hosts and guests. 2D ROESY investigation for the complexation between host and guest further confirms the cooperative binding of bridged cyclodextrin 1 with guest.     

Preparation of Ln3-xEuxS4 （Ln=Ce,Pr, and Nd） ceramics by pressureless sintering

The preparation of ternary rare earth sulfides of Ln3-xEuxS4 （Ln = Ce, Pr, and Nd） ceramics was investigated, and the effect of Eu substitution on Ln3-xEuxS4 ceramics was also studied. Ln3-xEuxS4 powders were synthesized by the sulfurization of their oxide powders using carbon disulfide gas. Ln3-xEuxS4 ceramics were sintered by pressure-less sintering method. All pressureless sintered Ln3-xEuxS4 ceramics crystallized in y-phase. It was found that Eu substitution could improve the density of Ln3-xEuxS4 ceramics. Furthermore, Eu substitution might narrow the optical band gaps of Ln3-xEuxS4 ceramics.     

New crystal structure of molecular complex 1-piperidine carboxylate-piperidinium-H<Subscript>2</Subscript>O studied by X-ray single crystal diffraction

Piperidine absorbs CO2 and H2O in air to form a molecular complex： piperidium-l-piperidinecarboxylate-H2O. The structure of the complex was characterized by X-ray single crystal diffraction. The crystal structure was determined to be triclinic, space group P1^-with a=0.648 6（8） nm, b=0.809 200） nm, c= 1.357 1（16） nm, a=96.96706）°, β =102.506（15）°,γ=104.202 05）°, Z=2. The complex is stabilized via five hydrogen bonds between the three components, N-O electrostatic interaction and O-O interaction （electron transfer） betweenl-piperidinecarboxylate and H2O. Due to electron transference of carbamate ion, the oxygen atom in water molecule is strongly negatively charged and the O-H bond is considerably shorter than that of the free molecule of water. The formation of the molecular complex is a reversible process and will decompose upon heating. The mechanism of formation and stabilization is further investigated herein.     

An approach to Hang Seng Index in Hong Kong stock market based on network topological statistics

THE STOCK MARKET IS A STRONGLY FLUCTUATING AND INTER- ACTING COMPLEX SYSTEM. IN A STOCK MARKET, A SINGLE NUMBER, NAMELY THE STOCK INDEX, COMPACTLY CHARACTER- IZES ITS PERFORMANCE. THE FLUCTUATIONS OF THE STOCK IN- DEX BRING ABOUT AN EVOLVING COMPLEX SYSTE…     

蛋白质系统突变分析及系综优化算法的计算机实现

蛋白质突变分析是研究蛋白质活性位点、蛋白质相互作用分析及蛋白质功能的重要手段,由于常规的实验方法费时费力,计算机模拟蛋白质位点系统突变,并对突变的效果作合理的评价就显得尤为重要.介绍了计算机模拟蛋白质位点系统突变的实现方法,利用系综优化算法对各突变体的自由能进行计算,并提出合理的评估标准.与现有的生物学实验结果相比较,计算机模拟计算的正确率为69.23%,假阳性率为30.77%.     

Synthesis,characterization and photoluminescence of aluminum <Emphasis Type="Italic">N</Emphasis>-aryloxo functionalized <Emphasis Type="Italic">β</Emphasis>-ketoiminate complexes

The synthesis, characterization and luminescent properties of aluminum complexes containing a dianionic N-aryloxo functionalized β-ketoiminate ligand are presented. 4-(2-Hydroxy-5-R-phenyl)imino-2-pentanone (R = Me, L¹H₂; R = tert-butyl, L²H₂) ligands reacted with AlEt₃ in tetrahydrofuran to give the aluminum complexes (L¹AlEt)₂ (1) and (L²AlEt)₂ (2) in reasonable isolated yields. X-ray diffraction revealed that complexes 1 and 2 have solvent-free centrosymmetric dimeric structures, and each aluminum center has distorted trigonal bipyramidal geometry. At room temperature, complexes 1 and 2 exhibit blue photoluminescence in acetonitrile with maximum emission wavelengths of 419 and 413 nm, respectively.     

Nbn(n=2-15)小团簇的第一性原理研究

【目的】研究纳米尺寸Nbn小团簇的结构演变过程,为进一步讨论Nbn小团簇的催化氧化性质提供参考。【方法】采用基于密度泛函理论(包括PW91和BLYP函数)的第一性原理计算方法对Nbn(n=2-15)小团簇的几何结构进行优化计算。【结果】随着原子数n的增加,Nbn(n=2-15)小团簇的结构及其特性具有明显的变化,平均每原子结合能(Binding Energy)随着原子数的增加呈递减趋势。【结论】Nbn(n=2-15)小团簇随尺寸变化具有明显的奇偶震荡性,n为偶数时比n为奇数时的结构稳定,其中Nb4、Nb6、Nb8、Nb10、Nb12小团簇结构较为稳定。     

Thermodynamic determination of fragility in La-based glass-forming liquid

Differences in the thermodynamic functions between the liquid and crystalline states of La-based bulk metallic glasses alloys were calculated with the specific heat capacity Cp and the fusion heat ΔHf,which we measured. Fragility indexes having different thermodynamic definitions were calculated from the temperature dependence of excess entropy ΔSliq-cry. It is ambiguous for La-based glass-forming liquid to evaluate fragility from the intercepts of ΔSliq-cry-temperature curves. We found that the thermodynam...     

New method on constructing analytic potential function of diatomic molecules

A new method on constructing analytical potential energy functions is presented, and then a relatively universal analytical potential energy function for precisely calculating the spectra of diatomic molecules and ions is derived. Furthermore, six kinds of common potential energy curves containing three main potential curves i.e. steady state, metastable state and repulsive state are obtained from this potential energy function. Finally, spectroscopic parameters of thirteen diatomic molecules and ions including BeD-X ² Σ ⁺, BeT-X ² Σ ⁺ and Na₂-X ¹ Σ _g ⁺ etc are calculated by using the potential function, as a consequence, all calculation results are in good agreement with experimental data. Biography: YU Changfeng (1962–), male, Associate professor, research direction: theoretical physics.     

Spectroscopic investigation of the interaction between human serum albumins and 10-hydroxycamptothecin

The binding reaction between 10-hydroxycamptothecin (10-HCPT) and human serum albumins (HSA) is studied by means of fluorescence spectroscopy, UV-Vis absorption spectrum, 1H NMR spectrum, and molecular simulation. The results indicate that the binding reaction of 10-HCPT and HSA is a single static quenching process, and the binding equilibrium constant for 10-HCPT binding with HSA is estimated K ₀= 4.93×10⁴ L · mol⁻¹ at 25 °C with the molar ratio of 1:1. The distance (r) and energy transfer efficiency (E) between donor (HSA) and acceptor (10-HCPT) are obtained as follows, r =3.51 nm; E =0.27. The enthalpy change (ΔH ^⦵) and entropy change (ΔS ^⦵) are calculated at different temperatures, and the hydrophobic force and shidipole force are the functions in the reaction. The results show that 10-HCPT binds within the subdomain II A of HSA by the hydrophobic force, and the 10-OH and 20-OH of 10-HCPT bind with both residue Leu-238 of HSA and Ala 291 of HSA by hydrogen bonds. Biography: LI Guizhi(1962–), female, Associate professor, research direction: organic analysis.     

Application of an Optical Biosensor to Study the Interaction between Porphyrins and Wheat Germ Agglutinin

0Introduction Porphyrinderivativeshavebeenusedasphotosensitizersinphotodynamictherapy(PDT),anewapproachdevel opedforthetreatmentofcancer[1].Cationwater solublepor phyrinsareofconsiderableinterestowingtotheirpossiblebio medicalapplications[2].Inwhich,theinhibiteffectonthe growthmetabolismofE.coliandcancercellHL60ofmeso tetra(4N ethylacetatepyridyl)porphyrin(H2NEAE pp)and itsZn(Ⅱ)complexform(ZnNEAE pp)havebeenrecentlyin vestigated[3,4].Toenhancetumor locationandanticancerac tivitiesofdr…     

Molecule modification and mass deposition induced by the implantation of low energy Fe+ ion beams into amino acids

Fe⁺ ion beams with the energy of 110 keV were implanted into films of L(+)-cysteine (HSCH₂CH(NH₂)COOH). One of the single crystals grown in hydrochloric acid solution with the implanted samples through slow evaporation was structurally characterized by the X-ray crystallography. The crystal is monoclinic, space group C2, with a = 1.8534(4) nm, b = 0.5234(1) nm, c = 0.7212(1) nm, β= 103.72°, V = 0.67965(3) nm³, Z = 4, F(000) = 144.0, D{clac} = 1.763 g · cm⁻³, μ(MoK _a = 1.06 mm⁻¹, T = 293(2) K. R = 0.0379, wR = 0.0835 for 660 observed reflections (I > 2σ(I)). The structural formula of the crystal compound is (CH₂CH(NH₂)NO₂)ClFe (M _r = 180.38 u). Products of heavy ion beam irradiation were purified and it was directly confirmed that the implanted Fe⁺ ions had been deposited in the novel molecules. The same doses of Fe⁺ ion beams of the same energy were implanted into films of L(+)-cysteine hydrochloride monohydrate. FTIR spectroscopy of the implanted samples proved that some of the original molecules were seriously damaged and significant modifications were induced.     

Roles of Phe58 residue in stabilizing structure of cytochrome b<Subscript>5</Subscript>

To understand effect of π-stacking interactions between the side chain of aromatic amino acids and the porphyrin ring on structures and properties in cytochrome b₅ (cyt b₅), the Phe58 residue was mutated to tyrosine and tryptophan, respectively by site-directed mutagenesis. The denaturation of cyt b₅ F58W and F58Y toward guanidine hydrochloride was examined by UV-visible and fluorescence spectroscopy. The kinetics of heme transfer reactions between apo-myoglobin and the mutants were studied. The results indicated that the mutation of F58 residue for Y58 or W58 reduced the interaction between of peptide and the heme group, resulting in decrease of the T _m and C _m values of the proteins, increase of the heme transfer reaction rate, and shifts of the redox potential.     

Genetic Algorithm-Based Approaches for Optimizing S-Boxes

0 Introduction Being as unique nonlinear components of block ci- pher algorithms, S-boxes provide the most important confusion effect, and directly influence the security of the algorithms. There are many ways to construct S-boxes[1-5]. On one hand, diffe…