Intermolecular interactions of formic acid with benzene: Energy decomposition analyses with ab initio MP2 and double‐hybrid density functional computations

The intermolecular interactions of formic acid (HCOOH) with benzene (C₆H₆) have been investigated using localized molecular orbital energy decomposition analyses (LMO‐EDA) with ab initio MP2 and several double‐hybrid density functionals. The molecular geometries of five HCOOH…C₆H₆ complexes and corresponding benchmark total interaction energies at the CCSD(T)/CBS level are taken from literature (Zhao et al., J. Chem. Theory Comput. 2009, 5, 2726). According to the results of LMO‐EDA with the MP2 method, the dispersion energies are found to be as important as the electrostatic energies for the total interaction energies of the five HCOOH…C₆H₆ complexes. Based on LMO‐EDA with the double‐hybrid density functionals of B2PLYP, B2K‐PLYP, B2T‐PLYP, and B2GP‐PLYP computations, two new parameters for the framework of B2PLYP are extrapolated. These two new parameters are tested with other 10 complexes involving C₆H₆ (Crittenden, J. Phys. Chem. A 2009, 113, 1663), and they perform well on predicting the corresponding total interaction energies. Interestingly, these two new parameters for the framework of B2PLYP also perform well on the noncovalent complexation energies database (NCCE31/05) developed by Truhlar's group (Zhao and Truhlar, J. Phys. Chem. A 2005, 109, 5656). Therefore, these two new parameters appear to be suitable for investigating the noncovalent interactions, and they are denoted as B2N‐PLYP, where N stands for the noncovalent interaction. This study is expected to provide new insight into the derivation of double‐hybrid density functionals for studying the noncovalent interactions. © 2013 Wiley Periodicals, Inc.     

姜黄素及其改性产物与皮胶原作用研究

我国使用天然染料历史悠久,但随着近代化学工业的发展,出现了合成染料,合成染料以其丰富多彩的色彩和优良的染色牢度而得以广泛应用,天然染料则受到冷落.     

On Some Topological Indices Defined via the Modified Sombor Matrix

Let G be a simple graph with the vertex set V={v1,…,vn} and denote by dvi the degree of the vertex vi. The modified Sombor index of G is the addition of the numbers (dvi2+dvj2)−1/2 over all of the edges vivj of G. The modified Sombor matrix AMS(G) of G is the n by n matrix such that its (i,j)-entry is equal to (dvi2+dvj2)−1/2 when vi and vj are adjacent and 0 otherwise. The modified Sombor spectral radius of G is the largest number among all of the eigenvalues of AMS(G). The sum of the absolute eigenvalues of AMS(G) is known as the modified Sombor energy of G. Two graphs with the same modified Sombor energy are referred to as modified Sombor equienergetic graphs. In this article, several bounds for the modified Sombor index, the modified Sombor spectral radius, and the modified Sombor energy are found, and the corresponding extremal graphs are characterized. By using computer programs (Mathematica and AutographiX), it is found that there exists only one pair of the modified Sombor equienergetic chemical graphs of an order of at most seven. It is proven that the modified Sombor energy of every regular, complete multipartite graph is 2; this result gives a large class of the modified Sombor equienergetic graphs. The (linear, logarithmic, and quadratic) regression analyses of the modified Sombor index and the modified Sombor energy together with their classical versions are also performed for the boiling points of the chemical graphs of an order of at most seven.     

Ultrasensitive Simultaneous Detection of Multiple Rare Modified Nucleosides as Promising Biomarkers in Low-Put Breast Cancer DNA Samples for Clinical Multi-Dimensional Diagnosis

Early cancer diagnosis is essential for successful treatment and prognosis, and modified nucleosides have attracted widespread attention as a promising group of cancer biomarkers. However, analyzing these modified nucleosides with an extremely low abundance is a great challenge, especially analyzing multiple modified nucleosides with a different abundance simultaneously. In this work, an ultrasensitive quantification method based on chemical labeling, coupled with LC-MS/MS analysis, was established for the simultaneous quantification of 5hmdC, 5fdC, 5hmdU and 5fdU. Additionally, the contents of 5mdC and canonical nucleosides could be obtained at the same time. Upon derivatization, the detection sensitivities of 5hmdC, 5fdC, 5hmdU and 5fdU were dramatically enhanced by several hundred times. The established method was further applied to the simultaneous detection of nine nucleosides with different abundances in about 2 μg genomic DNA of breast tissues from 20 breast cancer patients. The DNA consumption was less than other overall reported quantification methods, thereby providing an opportunity to monitor rare, modified nucleosides in precious samples and biology processes that could not be investigated before. The contents of 5hmdC, 5hmdU and 5fdU in tumor tissues and normal tissues adjacent to the tumor were significantly changed, indicating that these three modified nucleosides may play certain roles in the formation and development of tumors and be potential cancer biomarkers. While the detection rates of 5hmdC, 5hmdU and 5fdU alone as a biomarker for breast cancer samples were 95%, 75% and 85%, respectively, by detecting these three cancer biomarkers simultaneously, two of the three were 100% consistent with the overall trend. Therefore, simultaneous detection of multiple cancer biomarkers in clinical samples greatly improved the accuracy of cancer diagnosis, indicating that our method has great application potential in clinical multidimensional diagnosis.     

Synthesis,characterization and α‐amylase and α‐glucosidase inhibition studies of novel vanadyl chalcone complexes

A series of chalcone ligands and their corresponding vanadyl complexes of composition [VO (L^I–IV)₂(H₂O)₂]SO₄ (where L^I = 1,3‐Diphenylprop‐2‐en‐1‐one, L^II = 3‐(2‐Hydroxy‐phenyl)‐1‐phenyl‐propenone, L^III = 3‐(3‐Nitro‐phenyl)‐1‐phenyl‐propenone, L^IV = 3‐(4‐Methoxy‐phenyl)‐1‐phenyl‐propenone) have been synthesized and characterized using various spectroscopic (Fourier‐transform infrared, electrospray ionization mass, nuclear magnetic resonance, electron paramagnetic resonance, thermogravimetric analysis, vibrating sample magnetometer) and physico‐analytic techniques. Antidiabetic activities of synthesized complexes along with chalcones were evaluated by performing in vitro and in silico α‐amylase and α‐glucosidase inhibition studies. The obtained results displayed moderate to significant inhibition activity against both the enzymes by vanadyl chalcone complexes. The most potent complexes were further investigated for the enzyme kinetic studies and displayed the mixed inhibition for both the enzymes. Further, antioxidant activity of vanadyl chalcone complexes was evaluated for their efficiency to release oxidative stress using 2,2‐diphenyl‐1‐picryl‐hydrazyl‐hydrate assay, and two complexes (Complexes 2 and 4 ) have demonstrated remarkable antioxidant activity. All the complexes were found to possess promising antidiabetic and antioxidant potential.     

中空Ag纳米球壳的制备及性能表征

以改性聚苯乙烯微球为模板,采用化学镀法在聚苯乙烯微球表面包覆一层银,在四氢呋喃溶液中将聚苯乙烯微球溶解,得到中空Ag纳米球壳。采用扫描电镜、透射电镜和X射线衍射仪对样品进行了表征及分析,并用紫外可见分光光度计研究了粒子的光学性质。实验结果表明：运用此法成功地制备出中空Ag纳米球壳的内径为250 nm,壁厚约为15 nm,并且成功地使纳米粒子的紫外吸收光谱由600 nm红移至900 nm左右,实现了在可见光至近红外光区调节Ag纳米结构的吸收峰。     

多裂纹问题积分方程方法及相关问题

The content of thisreview consists of recent developments covering an advancedtreatment of multiple crack problems in plane elasticity. Severalelementary solutions are highlighted, which are the fundamentalsfor the formulation of the integral equations. The elementarysolutions include those initiated by point sources or by adistributed traction along the crack face. Two kinds of singularintegral equations, three kinds of Fredholm integral equations,and one kind of hypersingular integral equation are suggested forthe multiple crack problems in plane elasticity. Regularizationprocedures are also investigated. For the solution of the integralequations, the relevant quadrature rules are addressed. A varietyof methods for solving the multiple crack problems is introduced.Applications for the solution of the multiple crack problems arealso addressed. The concept of the modified complex potential(MCP) is emphasized, which will extend the solution range, forexample, from the multiple crack problem in an infinite plate tothat in a circular plate. Many multiple crack problems areaddressed. Those problems include: (i) multiple semi-infinitecrack problem, (ii) multiple crack problem with a general loading,(iii) multiple crack problem for the bonded half-planes, (iv)multiple crack problem for a finite region, (v) multiple crackproblem for a circular region, (vi) multiple crack problem inantiplane elasticity, (vii) T-stress in the multiple crackproblem, and (viii) periodic crack problem and many others. Thisreview article cites 187 references.      

Structure and catalytic activity of metal complexes fixed on carriers. Hydrodehalogenation of p-bromotoluene with chemically bonded hydrogen,catalyzed by immobilized rhodium(II) complexes

The structure of Rh(II) complexes with vigorous ligands immobilized on -aminopropyl-containing silicagel (-AMPS) and polymers containing 3(5)-methyl-pyrazole and imidazole groups, was investigated. It was shown by IR spectroscopy that the ligand surroundings are maintained after application only for the Rh(II) acetate complex. For the acetonitrile and hexafluoroacetylacetonate complexes there is a replacement of the ligands by amino groups of the carrier. [Rh₂(O₂CCH₃)₄] is significantly more active than other metal complexes immobilized on -AMPS in the hydrodehalogenation of p-bromotoluene by transfer of hydrogen from NaBH₄ and propanol-2.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 65–70, January, 1992.