Intermolecular interactions

International Nuclear Information System (INIS)

Kaplan, I.G.; Rodimova, O.B.; AN SSSR, Tomsk. Inst. Optiki Atmosfery)

1978-01-01

The present state of the intermolecular interaction theory is described. The general physical picture of the molecular interactions is given, the relative contributions of interactions of different types are analyzed (electrostatic, resonance, induction, dispersion, relativistic, magnetostatic and exchange), and the main ones in each range of separations are picked out. The methods of the potential curve calculations are considered, specific for definite separations between the interacting systems. The special attention is paid to the analysis of approximations used in different theoretical calculation methods

Argon intermolecular potential from a measurement of the total scattering cross-section

International Nuclear Information System (INIS)

Wong, Y.W.

1975-01-01

An inversion method to obtain accurate intermolecular potentials from experimental total cross section measurements is presented. This method is based on the high energy Massey--Smith approximation. The attractive portion of the potential is represented by a multi-parameter spline function and the repulsive part by a Morse function. The best fit potential is obtained by a least squares minimization based on comparison of experimental cross sections with those obtained by a Fourier transform of the reduced Massey--Smith phase shift curve. An experimental method was developed to obtain the total cross sections needed for the above inversion procedure. In this technique, integral cross sections are measured at various resolutions and the total cross section is obtained by extrapolating to infinite resolution. Experimental results obtained for the Ar--Ar system are in excellent agreement with total cross sections calculated using the Barker-Fisher-Watts potential. Inversion of the data to obtain a potential distinguishable from the BFW-potential requires an extension of the method based on the Massey--Smith approximation to permit use of JWKB phase shifts and was not attempted

New models for intermolecular repulsion and their application to Van Der Waals complexes and crystals of organic molecules

International Nuclear Information System (INIS)

Tsui, H.H.Y.

2001-01-01

Model intermolecular potentials are required for simulations of molecules in the gas, liquid, or solid phase. The widely used isotropic atom-atom model potentials are empirically fitted and based on the assumptions of transferability, combining rules and that atoms in molecules are spherical. This thesis develops a non-empirical method of modelling repulsion by applying the overlap model, which we show as a general non-empirical method of deriving repulsion potentials for a specific molecule. In this thesis, the repulsion parameters for an exponential atom-atom model potential are obtained from the ab initio charge density of a small organic molecule by making the assumption that the repulsion is proportional to the overlap of a pair of molecules. The proportionality constant is fixed by a limited number of intermolecular perturbation theory (IMPT) calculations. To complete the model potential, the electrostatic interaction is represented by a distributed multipole analysis, and the Slater-Kirkwood formula is used for the dispersion. These non-empirical potentials can reproduce experimental crystal structure when applied to crystal structure prediction of an oxyboryl derivative. A detailed study on further improving the overlap model was carried out for phenol-water, by including other minor intermolecular contributions of charge-transfer and penetration. High quality ab initio calculations on the complex were performed for use in comparison. To compare with experimental data, diffusion Monte Carlo simulations were performed with the potential, so that the effects of anharmonic zero-point motion on structure and energy of the system are included. When the system is too large for an IMPT calculation, the proportionality constant can be determined empirically by fitting the cell volume as shown in our study of crystal structures of chlorothalonil. This is used with an anisotropic repulsion model that has been derived for Cl and N atoms in chlorothalonil. This model

Ground state analytical ab initio intermolecular potential for the Cl2-water system

International Nuclear Information System (INIS)

Hormain, Laureline; Monnerville, Maurice; Toubin, Céline; Duflot, Denis; Pouilly, Brigitte; Briquez, Stéphane; Bernal-Uruchurtu, Margarita I.; Hernández-Lamoneda, Ramón

2015-01-01

The chlorine/water interface is of crucial importance in the context of atmospheric chemistry. Modeling the structure and dynamics at this interface requires an accurate description of the interaction potential energy surfaces. We propose here an analytical intermolecular potential that reproduces the interaction between the Cl 2 molecule and a water molecule. Our functional form is fitted to a set of high level ab initio data using the coupled-cluster single double (triple)/aug-cc-p-VTZ level of electronic structure theory for the Cl 2 − H 2 O complex. The potential fitted to reproduce the three minima structures of 1:1 complex is validated by the comparison of ab initio results of Cl 2 interacting with an increasing number of water molecules. Finally, the model potential is used to study the physisorption of Cl 2 on a perfectly ordered hexagonal ice slab. The calculated adsorption energy, in the range 0.27 eV, shows a good agreement with previous experimental results

The effect of the intermolecular potential formulation on the state-selected energy exchange rate coefficients in N2-N2 collisions.

Science.gov (United States)

Kurnosov, Alexander; Cacciatore, Mario; Laganà, Antonio; Pirani, Fernando; Bartolomei, Massimiliano; Garcia, Ernesto

2014-04-05

The rate coefficients for N2-N2 collision-induced vibrational energy exchange (important for the enhancement of several modern innovative technologies) have been computed over a wide range of temperature. Potential energy surfaces based on different formulations of the intramolecular and intermolecular components of the interaction have been used to compute quasiclassically and semiclassically some vibrational to vibrational energy transfer rate coefficients. Related outcomes have been rationalized in terms of state-to-state probabilities and cross sections for quasi-resonant transitions and deexcitations from the first excited vibrational level (for which experimental information are available). On this ground, it has been possible to spot critical differences on the vibrational energy exchange mechanisms supported by the different surfaces (mainly by their intermolecular components) in the low collision energy regime, though still effective for temperatures as high as 10,000 K. It was found, in particular, that the most recently proposed intermolecular potential becomes the most effective in promoting vibrational energy exchange near threshold temperatures and has a behavior opposite to the previously proposed one when varying the coupling of vibration with the other degrees of freedom. Copyright © 2014 Wiley Periodicals, Inc.

Transport properties in mixtures involving carbon dioxide at low and moderate density: test of several intermolecular potential energies and comparison with experiment

Science.gov (United States)

Moghadasi, Jalil; Yousefi, Fakhri; Papari, Mohammad Mehdi; Faghihi, Mohammad Ali; Mohsenipour, Ali Asghar

2009-09-01

It is the purpose of this paper to extract unlike intermolecular potential energies of five carbon dioxide-based binary gas mixtures including CO2-He, CO2-Ne, CO2-Ar, CO2-Kr, and CO2-Xe from viscosity data and compare the calculated potentials with other models potential energy reported in literature. Then, dilute transport properties consisting of viscosity, diffusion coefficient, thermal diffusion factor, and thermal conductivity of aforementioned mixtures are calculated from the calculated potential energies and compared with literature data. Rather accurate correlations for the viscosity coefficient of afore-cited mixtures embracing the temperature range 200 K < T < 3273.15 K is reproduced from the present unlike intermolecular potentials energy. Our estimated accuracies for the viscosity are to within ±2%. In addition, the calculated potential energies are used to present smooth correlations for other transport properties. The accuracies of the binary diffusion coefficients are of the order of ±3%. Finally, the unlike interaction energy and the calculated low density viscosity have been employed to calculate high density viscosities using Vesovic-Wakeham method.

Transport properties in mixtures involving carbon dioxide at low and moderate density: test of several intermolecular potential energies and comparison with experiment

Energy Technology Data Exchange (ETDEWEB)

Moghadasi, Jalil; Yousefi, Fakhri [Shiraz University, Department of Chemistry, Shiraz (Iran); Papari, Mohammad Mehdi; Faghihi, Mohammad Ali [Shiraz University of Technology, Department of Chemistry, Shiraz (Iran); Mohsenipour, Ali Asghar [University of Waterloo, Department of Chemical Engineering, Waterloo (Canada)

2009-09-15

It is the purpose of this paper to extract unlike intermolecular potential energies of five carbon dioxide-based binary gas mixtures including CO{sub 2}-He, CO{sub 2}-Ne, CO{sub 2}-Ar, CO{sub 2}-Kr, and CO{sub 2}-Xe from viscosity data and compare the calculated potentials with other models potential energy reported in literature. Then, dilute transport properties consisting of viscosity, diffusion coefficient, thermal diffusion factor, and thermal conductivity of aforementioned mixtures are calculated from the calculated potential energies and compared with literature data. Rather accurate correlations for the viscosity coefficient of afore-cited mixtures embracing the temperature range 200 Kintermolecular potentials energy. Our estimated accuracies for the viscosity are to within {+-}2%. In addition, the calculated potential energies are used to present smooth correlations for other transport properties. The accuracies of the binary diffusion coefficients are of the order of {+-}3%. Finally, the unlike interaction energy and the calculated low density viscosity have been employed to calculate high density viscosities using Vesovic-Wakeham method. (orig.)

Determination of intermolecular transfer integrals from DFT calculations

Energy Technology Data Exchange (ETDEWEB)

Baumeier, Bjoern; Andrienko, Denis [Max-Planck Institute for Polymer Research, Mainz (Germany)

2010-07-01

Theoretical studies of charge transport in organic conducting systems pose a unique challenge since they require multiscale schemes that combine quantum-chemical, molecular dynamics and kinetic Monte-Carlo calculations. The description of the mobility of electrons and holes in the hopping regime relies on the determination of intermolecular hopping rates in large scale morphologies. Using Marcus theory these rates can be calculated from intermolecular transfer integrals and on-site energies. Here we present a detailed computational study on the accuracy and efficiency of density-functional theory based approaches to the determination of intermolecular transfer integrals. First, it is demonstrated how these can be obtained from quantum-chemistry calculations by forming the expectation value of a dimer Fock operator with frontier orbitals of two neighboring monomers based on a projective approach. We then consider the prototypical example of one pair out of a larger morphology of Tris(8-hydroxyquinolinato)aluminium (Alq3) and study the influence of computational parameters, e.g. the choice of basis sets, exchange-correlation functional, and convergence criteria, on the calculated transfer integrals. The respective accuracies and efficiencies are compared in order to derive an optimal strategy for future simulations based on the full morphology.

Determination of a silane intermolecular force field potential model from an ab initio calculation

International Nuclear Information System (INIS)

Li, Arvin Huang-Te; Chao, Sheng D.; Chang, Chien-Cheng

2010-01-01

Intermolecular interaction potentials of the silane dimer in 12 orientations have been calculated by using the Hartree-Fock (HF) self-consistent theory and the second-order Moeller-Plesset (MP2) perturbation theory. We employed basis sets from Pople's medium-size basis sets [up to 6-311++G(3df, 3pd)] and Dunning's correlation consistent basis sets (up to the triply augmented correlation-consistent polarized valence quadruple-zeta basis set). We found that the minimum energy orientations were the G and H conformers. We have suggested that the Si-H attractions, the central silicon atom size, and electronegativity play essential roles in weakly binding of a silane dimer. The calculated MP2 potential data were employed to parametrize a five-site force field for molecular simulations. The Si-Si, Si-H, and H-H interaction parameters in a pairwise-additive, site-site potential model for silane molecules were regressed from the ab initio energies.

Intermolecular potential and rovibrational states of the H2O–D2 complex

International Nuclear Information System (INIS)

Avoird, Ad van der; Scribano, Yohann; Faure, Alexandre; Weida, Miles J.; Fair, Joanna R.; Nesbitt, David J.

2012-01-01

Graphical abstract: H 2 O–D 2 potential surface and pH 2 O–oD 2 ground state wave function, for planar geometries. Highlights: ► The interaction between H 2 O and H 2 is of great astrophysical interest. ► The rovibrational states of H 2 O–D 2 were computed on an ab initio potential surface. ► Results are compared with the rovibrational states of H 2 O–H 2 computed recently. ► We measured the high-resolution infrared spectrum of H 2 O–D 2 in the H 2 O bend region. ► Comparison with the calculations provides information on H 2 O–H 2 potential surface. - Abstract: A five-dimensional intermolecular potential for H 2 O–D 2 was obtained from the full nine-dimensional ab initio potential surface of Valiron et al. [P. Valiron, M. Wernli, A. Faure, L. Wiesenfeld, C. Rist, S. Kedžuch, J. Noga, J. Chem. Phys. 129 (2008) 134306] by averaging over the ground state vibrational wave functions of H 2 O and D 2 . On this five-dimensional potential with a well depth D e of 232.12 cm −1 we calculated the bound rovibrational levels of H 2 O–D 2 for total angular momentum J = 0–3. The method used to compute the rovibrational levels is similar to a scattering approach—it involves a basis of coupled free rotor wave functions for the hindered internal rotations and the overall rotation of the dimer—while it uses a discrete variable representation of the intermolecular distance coordinate R. The basis was adapted to the permutation symmetry associated with the para/ortho (p/o) nature of both H 2 O and D 2 , as well as to inversion symmetry. As expected, the H 2 O–D 2 dimer is more strongly bound than its H 2 O–H 2 isotopologue [cf. A. van der Avoird, D.J. Nesbitt, J. Chem. Phys. 134 (2011) 044314], with dissociation energies D 0 of 46.10, 50.59, 67.43, and 73.53 cm −1 for pH 2 O–oD 2 , oH 2 O–oD 2 , pH 2 O–pD 2 , and oH 2 O–pD 2 . A rotationally resolved infrared spectrum of H 2 O–D 2 was measured in the frequency region of the H 2 O bend

Improving intermolecular interactions in DFTB3 using extended polarization from chemical-potential equalization

Energy Technology Data Exchange (ETDEWEB)

Christensen, Anders S., E-mail: andersx@chem.wisc.edu, E-mail: cui@chem.wisc.edu; Cui, Qiang, E-mail: andersx@chem.wisc.edu, E-mail: cui@chem.wisc.edu [Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, Wisconsin 53706 (United States); Elstner, Marcus [Theoretische Chemische Biologie, Universität Karlsruhe, Kaiserstr. 12, 76131 Karlsruhe (Germany)

2015-08-28

Semi-empirical quantum mechanical methods traditionally expand the electron density in a minimal, valence-only electron basis set. The minimal-basis approximation causes molecular polarization to be underestimated, and hence intermolecular interaction energies are also underestimated, especially for intermolecular interactions involving charged species. In this work, the third-order self-consistent charge density functional tight-binding method (DFTB3) is augmented with an auxiliary response density using the chemical-potential equalization (CPE) method and an empirical dispersion correction (D3). The parameters in the CPE and D3 models are fitted to high-level CCSD(T) reference interaction energies for a broad range of chemical species, as well as dipole moments calculated at the DFT level; the impact of including polarizabilities of molecules in the parameterization is also considered. Parameters for the elements H, C, N, O, and S are presented. The Root Mean Square Deviation (RMSD) interaction energy is improved from 6.07 kcal/mol to 1.49 kcal/mol for interactions with one charged species, whereas the RMSD is improved from 5.60 kcal/mol to 1.73 for a set of 9 salt bridges, compared to uncorrected DFTB3. For large water clusters and complexes that are dominated by dispersion interactions, the already satisfactory performance of the DFTB3-D3 model is retained; polarizabilities of neutral molecules are also notably improved. Overall, the CPE extension of DFTB3-D3 provides a more balanced description of different types of non-covalent interactions than Neglect of Diatomic Differential Overlap type of semi-empirical methods (e.g., PM6-D3H4) and PBE-D3 with modest basis sets.

Central-field intermolecular potentials from the differential elastic scattering of H2(D2) by other molecules

International Nuclear Information System (INIS)

Kuppermann, Aron; Gordon, R.J.; Coggiola, M.J.

1974-01-01

Differential elastic scattering cross sections for the systems H 2 +O 2 , SF 6 , NH 3 , CO, and CH 4 and for D 2 +O 2 , SF 6 , and NH 3 have been obtained from crossed beam studies. In all cases, rapid quantum oscillations have been resolved which permit the determination of intermolecular potentiel parameters if a central-field assumption is adopted. These potentials were found to be independent of both the isotopic form of the hydrogen molecule, and the relative collision energy. As a result of this, and the ability of these spherical potentials to quantitatively describe the measured scattering, it is concluded that anisotropy effects do not seem important in these H 2 (D 2 ) systems

Desensitization of metastable intermolecular composites

Science.gov (United States)

Busse, James R [South Fork, CO; Dye, Robert C [Los Alamos, NM; Foley, Timothy J [Los Alamos, NM; Higa, Kelvin T [Ridgecrest, CA; Jorgensen, Betty S [Jemez Springs, NM; Sanders, Victor E [White Rock, NM; Son, Steven F [Los Alamos, NM

2011-04-26

A method to substantially desensitize a metastable intermolecular composite material to electrostatic discharge and friction comprising mixing the composite material with an organic diluent and removing enough organic diluent from the mixture to form a mixture with a substantially putty-like consistency, as well as a concomitant method of recovering the metastable intermolecular composite material.

Characterizing the Polymer:Fullerene Intermolecular Interactions

KAUST Repository

Sweetnam, Sean

2016-02-02

Polymer:fullerene solar cells depend heavily on the electronic coupling of the polymer and fullerene molecular species from which they are composed. The intermolecular interaction between the polymer and fullerene tends to be strong in efficient photovoltaic systems, as evidenced by efficient charge transfer processes and by large changes in the energetics of the polymer and fullerene when they are molecularly mixed. Despite the clear presence of these strong intermolecular interactions between the polymer and fullerene, there is not a consensus on the nature of these interactions. In this work, we use a combination of Raman spectroscopy, charge transfer state absorption, and density functional theory calculations to show that the intermolecular interactions do not appear to be caused by ground state charge transfer between the polymer and fullerene. We conclude that these intermolecular interactions are primarily van der Waals in nature. © 2016 American Chemical Society.

Intermolecular and surface forces

CERN Document Server

Israelachvili, Jacob N

2011-01-01

This reference describes the role of various intermolecular and interparticle forces in determining the properties of simple systems such as gases, liquids and solids, with a special focus on more complex colloidal, polymeric and biological systems. The book provides a thorough foundation in theories and concepts of intermolecular forces, allowing researchers and students to recognize which forces are important in any particular system, as well as how to control these forces. This third edition is expanded into three sections and contains five new chapters over the previous edition.· starts fr

Competing Intramolecular vs. Intermolecular Hydrogen Bonds in Solution

Directory of Open Access Journals (Sweden)

Peter I. Nagy

2014-10-01

Full Text Available A hydrogen bond for a local-minimum-energy structure can be identified according to the definition of the International Union of Pure and Applied Chemistry (IUPAC recommendation 2011 or by finding a special bond critical point on the density map of the structure in the framework of the atoms-in-molecules theory. Nonetheless, a given structural conformation may be simply favored by electrostatic interactions. The present review surveys the in-solution competition of the conformations with intramolecular vs. intermolecular hydrogen bonds for different types of small organic molecules. In their most stable gas-phase structure, an intramolecular hydrogen bond is possible. In a protic solution, the intramolecular hydrogen bond may disrupt in favor of two solute-solvent intermolecular hydrogen bonds. The balance of the increased internal energy and the stabilizing effect of the solute-solvent interactions regulates the new conformer composition in the liquid phase. The review additionally considers the solvent effects on the stability of simple dimeric systems as revealed from molecular dynamics simulations or on the basis of the calculated potential of mean force curves. Finally, studies of the solvent effects on the type of the intermolecular hydrogen bond (neutral or ionic in acid-base complexes have been surveyed.

Calculation of intermolecular potentials for H2−H2 and H2−O2 dimers ab initio and prediction of second virial coefficients

International Nuclear Information System (INIS)

Pham Van, Tat; Deiters, Ulrich K.

2015-01-01

Highlights: • We construct the angular orientations of dimers H 2 −H 2 and H 2 −O 2 . • We calculate the ab initio intermolecular interaction energies for all built orientations. • Extrapolating the interaction energies to the complete basis set limit aug-cc-pV23Z. • We develop two 5-site ab initio intermolecular potentials of dimers H 2 −H 2 , H 2 −O 2 . • Calculating the virial coefficients of dimer H 2 −H 2 and H 2 −O 2 . - Abstract: The intermolecular interaction potentials of the dimers H 2 −H 2 and H 2 −O 2 were calculated from quantum mechanics, using coupled-cluster theory CCSD(T) and correlation-consistent basis sets aug-cc-pVmZ (m = 2, 3); the results were extrapolated to the basis set limit aug-cc-pV23Z. The interaction energies were corrected for the basis set superposition error with the counterpoise scheme. For comparison also Møller–Plesset perturbation theory (at levels 2–4) with the basis sets aug-cc-pVTZ were considered, but the results proved inferior. The quantum mechanical results were used to construct analytical pair potential functions. From these functions the second virial coefficients of hydrogen and the cross virial coefficients of the hydrogen–oxygen system were obtained by integration; in both cases corrections for quantum effects were included. The results agree well with experimental data, if available, or with empirical correlations

Intermolecular potential and rovibrational states of the H{sub 2}O-D{sub 2} complex

Energy Technology Data Exchange (ETDEWEB)

Avoird, Ad van der, E-mail: A.vanderAvoird@theochem.ru.nl [Theoretical Chemistry, Institute for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen (Netherlands); Scribano, Yohann [Laboratoire Interdisciplinaire Carnot de Bourgogne-UMR 5209, CNRS-Universite de Bourgogne, 9 Av. Alain Savary, B.P. 47870, F-21078 Dijon Cedex (France); Faure, Alexandre [UJF-Grenoble 1/CNRS, Institut de Planetologie et d' Astrophysique de Grenoble (IPAG) UMR 5274, Grenoble F-38041 (France); Weida, Miles J. [Daylight Solutions, 15378 Avenue of Science, San Diego, CA 92128 (United States); Fair, Joanna R. [Department of Radiology, MSC10 5530, 1 University of New Mexico, Albuquerque, NM 87131-0001 (United States); Nesbitt, David J. [JILA, University of Colorado and National Institute of Standards and Technology, and Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309-0440 (United States)

2012-05-03

Graphical abstract: H{sub 2}O-D{sub 2} potential surface and pH{sub 2}O-oD{sub 2} ground state wave function, for planar geometries. Highlights: Black-Right-Pointing-Pointer The interaction between H{sub 2}O and H{sub 2} is of great astrophysical interest. Black-Right-Pointing-Pointer The rovibrational states of H{sub 2}O-D{sub 2} were computed on an ab initio potential surface. Black-Right-Pointing-Pointer Results are compared with the rovibrational states of H{sub 2}O-H{sub 2} computed recently. Black-Right-Pointing-Pointer We measured the high-resolution infrared spectrum of H{sub 2}O-D{sub 2} in the H{sub 2}O bend region. Black-Right-Pointing-Pointer Comparison with the calculations provides information on H{sub 2}O-H{sub 2} potential surface. - Abstract: A five-dimensional intermolecular potential for H{sub 2}O-D{sub 2} was obtained from the full nine-dimensional ab initio potential surface of Valiron et al. [P. Valiron, M. Wernli, A. Faure, L. Wiesenfeld, C. Rist, S. Kedzuch, J. Noga, J. Chem. Phys. 129 (2008) 134306] by averaging over the ground state vibrational wave functions of H{sub 2}O and D{sub 2}. On this five-dimensional potential with a well depth D{sub e} of 232.12 cm{sup -1} we calculated the bound rovibrational levels of H{sub 2}O-D{sub 2} for total angular momentum J = 0-3. The method used to compute the rovibrational levels is similar to a scattering approach-it involves a basis of coupled free rotor wave functions for the hindered internal rotations and the overall rotation of the dimer-while it uses a discrete variable representation of the intermolecular distance coordinate R. The basis was adapted to the permutation symmetry associated with the para/ortho (p/o) nature of both H{sub 2}O and D{sub 2}, as well as to inversion symmetry. As expected, the H{sub 2}O-D{sub 2} dimer is more strongly bound than its H{sub 2}O-H{sub 2} isotopologue [cf. A. van der Avoird, D.J. Nesbitt, J. Chem. Phys. 134 (2011) 044314], with dissociation energies D

Noncovalent Intermolecular Interactions in Organic Electronic Materials: Implications for the Molecular Packing vs Electronic Properties of Acenes

KAUST Repository

Sutton, Christopher; Risko, Chad; Bredas, Jean-Luc

2015-01-01

Noncovalent intermolecular interactions, which can be tuned through the toolbox of synthetic chemistry, determine not only the molecular packing but also the resulting electronic, optical, and mechanical properties of materials derived from π

Character of intermolecular interaction in pyridine-argon complex: Ab initio potential energy surface, internal dynamics, and interrelations between SAPT energy components

Energy Technology Data Exchange (ETDEWEB)

Makarewicz, Jan, E-mail: jama@amu.edu.pl; Shirkov, Leonid [Faculty of Chemistry, Adam Mickiewicz University, Umultowska 89b, 61-614 Poznań (Poland)

2016-05-28

The pyridine-Ar (PAr) van der Waals (vdW) complex is studied using a high level ab initio method. Its structure, binding energy, and intermolecular vibrational states are determined from the analytical potential energy surface constructed from interaction energy (IE) values computed at the coupled cluster level of theory with single, double, and perturbatively included triple excitations with the augmented correlation consistent polarized valence double-ζ (aug-cc-pVDZ) basis set complemented by midbond functions. The structure of the complex at its global minimum with Ar at a distance of 3.509 Å from the pyridine plane and shifted by 0.218 Å from the center of mass towards nitrogen agrees well with the corresponding equilibrium structure derived previously from the rotational spectrum of PAr. The PAr binding energy D{sub e} of 392 cm{sup −1} is close to that of 387 cm{sup −1} calculated earlier at the same ab initio level for the prototypical benzene-Ar (BAr) complex. However, under an extension of the basis set, D{sub e} for PAr becomes slightly lower than D{sub e} for BAr. The ab initio vdW vibrational energy levels allow us to estimate the reliability of the methods for the determination of the vdW fundamentals from the rotational spectra. To disclose the character of the intermolecular interaction in PAr, the symmetry-adapted perturbation theory (SAPT) is employed for the analysis of different physical contributions to IE. It is found that SAPT components of IE can be approximately expressed in the binding region by only two of them: the exchange repulsion and dispersion energy. The total induction effect is negligible. The interrelations between various SAPT components found for PAr are fulfilled for a few other complexes involving aromatic molecules and Ar or Ne, which indicates that they are valid for all rare gas (Rg) atoms and aromatics.

Ab initio study of the CO-N2 complex: a new highly accurate intermolecular potential energy surface and rovibrational spectrum

DEFF Research Database (Denmark)

Cybulski, Hubert; Henriksen, Christian; Dawes, Richard

2018-01-01

A new, highly accurate ab initio ground-state intermolecular potential-energy surface (IPES) for the CO-N2 complex is presented. Thousands of interaction energies calculated with the CCSD(T) method and Dunning's aug-cc-pVQZ basis set extended with midbond functions were fitted to an analytical...... function. The global minimum of the potential is characterized by an almost T-shaped structure and has an energy of -118.2 cm-1. The symmetry-adapted Lanczos algorithm was used to compute rovibrational energies (up to J = 20) on the new IPES. The RMSE with respect to experiment was found to be on the order...... of 0.038 cm-1 which confirms the very high accuracy of the potential. This level of agreement is among the best reported in the literature for weakly bound systems and considerably improves on those of previously published potentials....

Desensitization and recovery of metastable intermolecular composites

Science.gov (United States)

Busse, James R [South Fork, CO; Dye, Robert C [Los Alamos, NM; Foley, Timothy J [Los Alamos, NM; Higa, Kelvin T [Ridgecrest, CA; Jorgensen, Betty S [Jemez Springs, NM; Sanders, Victor E [White Rock, NM; Son, Steven F [Los Alamos, NM

2010-09-07

A method to substantially desensitize a metastable intermolecular composite material to electrostatic discharge and friction comprising mixing the composite material with an organic diluent and removing enough organic diluent from the mixture to form a mixture with a substantially putty-like consistency, as well as a concomitant method of recovering the metastable intermolecular composite material.

Noncovalent Intermolecular Interactions in Organic Electronic Materials: Implications for the Molecular Packing vs Electronic Properties of Acenes

KAUST Repository

Sutton, Christopher

2015-10-30

Noncovalent intermolecular interactions, which can be tuned through the toolbox of synthetic chemistry, determine not only the molecular packing but also the resulting electronic, optical, and mechanical properties of materials derived from π-conjugated molecules, oligomers, and polymers. Here, we provide an overview of the theoretical underpinnings of noncovalent intermolecular interactions and briefly discuss the computational chemistry approaches used to understand the magnitude of these interactions. These methodologies are then exploited to illustrate how noncovalent intermolecular interactions impact important electronic properties-such as the electronic coupling between adjacent molecules, a key parameter for charge-carrier transport-through a comparison between the prototype organic semiconductor pentacene with a series of N-substituted heteropentacenes. Incorporating an understanding of these interactions into the design of organic semiconductors can assist in developing novel materials systems from this fascinating molecular class. © 2015 American Chemical Society.

Modeling Adsorption-Desorption Processes at the Intermolecular Interactions Level

Science.gov (United States)

Varfolomeeva, Vera V.; Terentev, Alexey V.

2018-01-01

Modeling of the surface adsorption and desorption processes, as well as the diffusion, are of considerable interest for the physical phenomenon under study in ground tests conditions. When imitating physical processes and phenomena, it is important to choose the correct parameters to describe the adsorption of gases and the formation of films on the structural materials surface. In the present research the adsorption-desorption processes on the gas-solid interface are modeled with allowance for diffusion. Approaches are proposed to describe the adsorbate distribution on the solid body surface at the intermolecular interactions level. The potentials of the intermolecular interaction of water-water, water-methane and methane-methane were used to adequately modeling the real physical and chemical processes. The energies calculated by the B3LYP/aug-cc-pVDZ method. Computational algorithms for determining the average molecule area in a dense monolayer, are considered here. Differences in modeling approaches are also given: that of the proposed in this work and the previously approved probabilistic cellular automaton (PCA) method. It has been shown that the main difference is due to certain limitations of the PCA method. The importance of accounting the intermolecular interactions via hydrogen bonding has been indicated. Further development of the adsorption-desorption processes modeling will allow to find the conditions for of surface processes regulation by means of quantity adsorbed molecules control. The proposed approach to representing the molecular system significantly shortens the calculation time in comparison with the use of atom-atom potentials. In the future, this will allow to modeling the multilayer adsorption at a reasonable computational cost.

Ab initio calculation of intermolecular potentials for dimer Cl_2-Cl_2 and prediction of second virial coefficients

International Nuclear Information System (INIS)

Nguyen Thanh Duoc; Nguyen Thi Ai Nhung; Tran Duong; Pham Van Tat

2015-01-01

The results presented in this paper are the ab initio intermolecular potentials and the second virial coefficient, B_2 (T) of the dimer Cl_2-Cl_2. These ab initio potentials were proposed by the quantum chemical calculations at high level of theory CCSD(T) with basis sets of Dunning valence correlation-consistent aug-cc-pVmZ (m = 2, 3); these results were extrapolated to complete basis set limit aug-cc-pV23Z. The ab initio energies of complete basis set limit aug-cc-pV23Z resulted from the exponential extrapolation were used to construct the 5-site pair potential functions. The second virial coefficients for this dimer were predicted from those with four-dimensional integration. The second virial coefficients were also corrected to first-order quantum effects. The results turn out to be in good agreement with experimental data, if available, or with those from empirical correlation. The quality of ab initio 5-site potentials proved the reliability for prediction of molecular thermodynamic properties. (author)

Rhodium(III)-Catalyzed Activation of C(sp3)-H Bonds and Subsequent Intermolecular Amidation at Room Temperature.

Science.gov (United States)

Huang, Xiaolei; Wang, Yan; Lan, Jingbo; You, Jingsong

2015-08-03

Disclosed herein is a Rh(III)-catalyzed chelation-assisted activation of unreactive C(sp3)-H bonds, thus enabling an intermolecular amidation to provide a practical and step-economic route to 2-(pyridin-2-yl)ethanamine derivatives. Substrates with other N-donor groups are also compatible with the amidation. This protocol proceeds at room temperature, has a relatively broad functional-group tolerance and high selectivity, and demonstrates the potential of rhodium(III) in the promotive functionalization of unreactive C(sp3)-H bonds. A rhodacycle having a SbF6(-) counterion was identified as a plausible intermediate. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Theoretical studies for the N2–N2O van der Waals complex: The potential energy surface, intermolecular vibrations, and rotational transition frequencies

International Nuclear Information System (INIS)

Zheng, Rui; Zheng, Limin; Yang, Minghui; Lu, Yunpeng

2015-01-01

Theoretical studies of the potential energy surface (PES) and bound states are performed for the N 2 –N 2 O van der Waals (vdW) complex. A four-dimensional intermolecular PES is constructed at the level of single and double excitation coupled-cluster method with a non-iterative perturbation treatment of triple excitations [CCSD(T)] with aug-cc-pVTZ basis set supplemented with bond functions. Two equivalent T-shaped global minima are located, in which the O atom of N 2 O monomer is near the N 2 monomer. The intermolecular fundamental vibrational states are assigned by inspecting the orientation of the nodal surface of the wavefunctions. The calculated frequency for intermolecular disrotation mode is 23.086 cm −1 , which is in good agreement with the available experimental data of 22.334 cm −1 . A negligible tunneling splitting with the value of 4.2 MHz is determined for the ground vibrational state and the tunneling splitting increases as the increment of the vibrational frequencies. Rotational levels and transition frequencies are calculated for both isotopomers 14 N 2 –N 2 O and 15 N 2 –N 2 O. The accuracy of the PES is validated by the good agreement between theoretical and experimental results for the transition frequencies and spectroscopic parameters

Importance of the Donor:Fullerene intermolecular arrangement for high-efficiency organic photovoltaics

KAUST Repository

Graham, Kenneth; Cabanetos, Clement; Jahnke, Justin P.; Idso, Matthew N.; El Labban, Abdulrahman; Ngongang Ndjawa, Guy Olivier; Heumueller, Thomas; Vandewal, Koen; Salleo, Alberto; Chmelka, Bradley F.; Amassian, Aram; Beaujuge, Pierre; McGehee, Michael D.

2014-01-01

The performance of organic photovoltaic (OPV) material systems are hypothesized to depend strongly on the intermolecular arrangements at the donor:fullerene interfaces. A review of some of the most efficient polymers utilized in polymer:fullerene PV devices, combined with an analysis of reported polymer donor materials wherein the same conjugated backbone was used with varying alkyl substituents, supports this hypothesis. Specifically, the literature shows that higher-performing donor-acceptor type polymers generally have acceptor moieties that are sterically accessible for interactions with the fullerene derivative, whereas the corresponding donor moieties tend to have branched alkyl substituents that sterically hinder interactions with the fullerene. To further explore the idea that the most beneficial polymer:fullerene arrangement involves the fullerene docking with the acceptor moiety, a family of benzo[1,2-b:4,5-b]dithiophene-thieno[3,4-c]pyrrole-4,6-dione polymers (PBDTTPD derivatives) was synthesized and tested in a variety of PV device types with vastly different aggregation states of the polymer. In agreement with our hypothesis, the PBDTTPD derivative with a more sterically accessible acceptor moiety and a more sterically hindered donor moiety shows the highest performance in bulk-heterojunction, bilayer, and low-polymer concentration PV devices where fullerene derivatives serve as the electron-accepting materials. Furthermore, external quantum efficiency measurements of the charge-transfer state and solid-state two-dimensional (2D) 13C{1H} heteronuclear correlation (HETCOR) NMR analyses support that a specific polymer:fullerene arrangement is present for the highest performing PBDTTPD derivative, in which the fullerene is in closer proximity to the acceptor moiety of the polymer. This work demonstrates that the polymer:fullerene arrangement and resulting intermolecular interactions may be key factors in determining the performance of OPV material systems

Importance of the Donor:Fullerene intermolecular arrangement for high-efficiency organic photovoltaics

KAUST Repository

Graham, Kenneth

2014-07-09

The performance of organic photovoltaic (OPV) material systems are hypothesized to depend strongly on the intermolecular arrangements at the donor:fullerene interfaces. A review of some of the most efficient polymers utilized in polymer:fullerene PV devices, combined with an analysis of reported polymer donor materials wherein the same conjugated backbone was used with varying alkyl substituents, supports this hypothesis. Specifically, the literature shows that higher-performing donor-acceptor type polymers generally have acceptor moieties that are sterically accessible for interactions with the fullerene derivative, whereas the corresponding donor moieties tend to have branched alkyl substituents that sterically hinder interactions with the fullerene. To further explore the idea that the most beneficial polymer:fullerene arrangement involves the fullerene docking with the acceptor moiety, a family of benzo[1,2-b:4,5-b]dithiophene-thieno[3,4-c]pyrrole-4,6-dione polymers (PBDTTPD derivatives) was synthesized and tested in a variety of PV device types with vastly different aggregation states of the polymer. In agreement with our hypothesis, the PBDTTPD derivative with a more sterically accessible acceptor moiety and a more sterically hindered donor moiety shows the highest performance in bulk-heterojunction, bilayer, and low-polymer concentration PV devices where fullerene derivatives serve as the electron-accepting materials. Furthermore, external quantum efficiency measurements of the charge-transfer state and solid-state two-dimensional (2D) 13C{1H} heteronuclear correlation (HETCOR) NMR analyses support that a specific polymer:fullerene arrangement is present for the highest performing PBDTTPD derivative, in which the fullerene is in closer proximity to the acceptor moiety of the polymer. This work demonstrates that the polymer:fullerene arrangement and resulting intermolecular interactions may be key factors in determining the performance of OPV material systems

Systematic study on intermolecular valence-band dispersion in molecular crystalline films

International Nuclear Information System (INIS)

Yamane, Hiroyuki; Kosugi, Nobuhiro

2015-01-01

Highlights: • Intermolecular valence-band dispersion of crystalline films of phthalocyanines. • Intermolecular transfer integral versus lattice constant. • Site-specific intermolecular interaction and resultant valence-band dispersion. • Band narrowing effect induced by elevated temperature. - Abstract: Functionalities of organic semiconductors are governed not only by individual properties of constituent molecules but also by solid-state electronic states near the Fermi level such as frontier molecular orbitals, depending on weak intermolecular interactions in various conformations. The individual molecular property has been widely investigated in detail; on the other hand, the weak intermolecular interaction is difficult to investigate precisely due to the presence of the structural and thermal energy broadenings in organic solids. Here we show quite small but essential intermolecular valence band dispersions and their temperature dependence of sub-0.1-eV scale in crystalline films of metal phthalocyanines (H_2Pc, ZnPc, CoPc, MnPc, and F_1_6ZnPc) by using angle-resolved photoemission spectroscopy (ARPES) with synchrotron radiation. The observed bands show intermolecular and site dependent dispersion widths, phases, and periodicities, for different chemical substitution of terminal groups and central metals in the phthalocyanine molecule. The precise and systematic band-dispersion measurement would be a credible approach toward the comprehensive understanding of intermolecular interactions and resultant charge transport properties as well as their tuning by substituents in organic molecular systems.

Synthesis of benzimidazoles by potassium tert-butoxide-promoted intermolecular cyclization reaction of 2-iodoanilines with nitriles.

Science.gov (United States)

Xiang, Shi-Kai; Tan, Wen; Zhang, Dong-Xue; Tian, Xian-Li; Feng, Chun; Wang, Bi-Qin; Zhao, Ke-Qing; Hu, Ping; Yang, Hua

2013-11-14

The synthesis of benzimidazoles by intermolecular cyclization reaction of 2-iodoanilines with nitriles has been developed. These reactions proceeded without the aid of any transition metals or ligands and just using KOBu(t) as the base. A variety of substituted benzimidazole derivatives can be synthesized by the approach.

Similarities between intra- and intermolecular hydrogen bonds in RNA kissing complexes found by means of cross-correlated relaxation

International Nuclear Information System (INIS)

Dittmer, Jens; Kim, Chul-Hyun; Bodenhausen, Geoffrey

2003-01-01

The bond lengths and dynamics of intra- and intermolecular hydrogen bonds in an RNA kissing complex have been characterized by determining the NMR relaxation rates of various double- and triple-quantum coherences that involve an imino proton and two neighboring nitrogen-15 nuclei belonging to opposite bases. New experiments allow one to determine the chemical shift anisotropy of the imino protons. The bond lengths derived from dipolar relaxation and the lack of modulations of the nitrogen chemical shifts indicate that the intermolecular hydrogen bonds which hold the kissing complex together are very similar to the intramolecular hydrogen bonds in the double-stranded stem of the RNA

Single-molecule magnets ``without'' intermolecular interactions

Science.gov (United States)

Wernsdorfer, W.; Vergnani, L.; Rodriguez-Douton, M. J.; Cornia, A.; Neugebauer, P.; Barra, A. L.; Sorace, L.; Sessoli, R.

2012-02-01

Intermolecular magnetic interactions (dipole-dipole and exchange) affect strongly the magnetic relaxation of crystals of single-molecule magnets (SMMs), especially at low temperature, where quantum tunneling of the magnetization (QTM) dominates. This leads to complex many-body problems [l]. Measurements on magnetically diluted samples are desirable to clearly sort out the behaviour of magnetically-isolated SMMs and to reveal, by comparison, the effect of intermolecular interactions. Here, we diluted a Fe4 SMM into a diamagnetic crystal lattice, affording arrays of independent and iso-oriented magnetic units. We found that the resonant tunnel transitions are much sharper, the tunneling efficiency changes significantly, and two-body QTM transitions disappear. These changes have been rationalized on the basis of a dipolar shuffling mechanism and of transverse dipolar fields, whose effect has been analyzed using a multispin model. Our findings directly prove the impact of intermolecular magnetic couplings on the SMM behaviour and disclose the magnetic response of truly-isolated giant spins in a diamagnetic crystalline environment.[4pt] [1] W. Wernsdorfer, at al, PRL 82, 3903 (1999); PRL 89, 197201 (2002); Nature 416, 406 (2002); IS Tupitsyn, PCE Stamp, NV Prokof'ev, PRB 69, 132406 (2004).

Quantifying intermolecular interactions of ionic liquids using cohesive energy densities

Science.gov (United States)

2017-01-01

For ionic liquids (ILs), both the large number of possible cation + anion combinations and their ionic nature provide a unique challenge for understanding intermolecular interactions. Cohesive energy density, ced, is used to quantify the strength of intermolecular interactions for molecular liquids, and is determined using the enthalpy of vaporization. A critical analysis of the experimental challenges and data to obtain ced for ILs is provided. For ILs there are two methods to judge the strength of intermolecular interactions, due to the presence of multiple constituents in the vapour phase of ILs. Firstly, cedIP, where the ionic vapour constituent is neutral ion pairs, the major constituent of the IL vapour. Secondly, cedC+A, where the ionic vapour constituents are isolated ions. A cedIP dataset is presented for 64 ILs. For the first time an experimental cedC+A, a measure of the strength of the total intermolecular interaction for an IL, is presented. cedC+A is significantly larger for ILs than ced for most molecular liquids, reflecting the need to break all of the relatively strong electrostatic interactions present in ILs. However, the van der Waals interactions contribute significantly to IL volatility due to the very strong electrostatic interaction in the neutral ion pair ionic vapour. An excellent linear correlation is found between cedIP and the inverse of the molecular volume. A good linear correlation is found between IL cedIP and IL Gordon parameter (which are dependent primarily on surface tension). ced values obtained through indirect methods gave similar magnitude values to cedIP. These findings show that cedIP is very important for understanding IL intermolecular interactions, in spite of cedIP not being a measure of the total intermolecular interactions of an IL. In the outlook section, remaining challenges for understanding IL intermolecular interactions are outlined. PMID:29308254

Quantifying intermolecular interactions of ionic liquids using cohesive energy densities.

Science.gov (United States)

Lovelock, Kevin R J

2017-12-01

For ionic liquids (ILs), both the large number of possible cation + anion combinations and their ionic nature provide a unique challenge for understanding intermolecular interactions. Cohesive energy density, ced , is used to quantify the strength of intermolecular interactions for molecular liquids, and is determined using the enthalpy of vaporization. A critical analysis of the experimental challenges and data to obtain ced for ILs is provided. For ILs there are two methods to judge the strength of intermolecular interactions, due to the presence of multiple constituents in the vapour phase of ILs. Firstly, ced IP , where the ionic vapour constituent is neutral ion pairs, the major constituent of the IL vapour. Secondly, ced C+A , where the ionic vapour constituents are isolated ions. A ced IP dataset is presented for 64 ILs. For the first time an experimental ced C+A , a measure of the strength of the total intermolecular interaction for an IL, is presented. ced C+A is significantly larger for ILs than ced for most molecular liquids, reflecting the need to break all of the relatively strong electrostatic interactions present in ILs. However, the van der Waals interactions contribute significantly to IL volatility due to the very strong electrostatic interaction in the neutral ion pair ionic vapour. An excellent linear correlation is found between ced IP and the inverse of the molecular volume. A good linear correlation is found between IL ced IP and IL Gordon parameter (which are dependent primarily on surface tension). ced values obtained through indirect methods gave similar magnitude values to ced IP . These findings show that ced IP is very important for understanding IL intermolecular interactions, in spite of ced IP not being a measure of the total intermolecular interactions of an IL. In the outlook section, remaining challenges for understanding IL intermolecular interactions are outlined.

An optimized intermolecular force field for hydrogen-bonded organic molecular crystals using atomic multipole electrostatics

International Nuclear Information System (INIS)

Pyzer-Knapp, Edward O.; Thompson, Hugh P. G.; Day, Graeme M.

2016-01-01

An empirically parameterized intermolecular force field is developed for crystal structure modelling and prediction. The model is optimized for use with an atomic multipole description of electrostatic interactions. We present a re-parameterization of a popular intermolecular force field for describing intermolecular interactions in the organic solid state. Specifically we optimize the performance of the exp-6 force field when used in conjunction with atomic multipole electrostatics. We also parameterize force fields that are optimized for use with multipoles derived from polarized molecular electron densities, to account for induction effects in molecular crystals. Parameterization is performed against a set of 186 experimentally determined, low-temperature crystal structures and 53 measured sublimation enthalpies of hydrogen-bonding organic molecules. The resulting force fields are tested on a validation set of 129 crystal structures and show improved reproduction of the structures and lattice energies of a range of organic molecular crystals compared with the original force field with atomic partial charge electrostatics. Unit-cell dimensions of the validation set are typically reproduced to within 3% with the re-parameterized force fields. Lattice energies, which were all included during parameterization, are systematically underestimated when compared with measured sublimation enthalpies, with mean absolute errors of between 7.4 and 9.0%

Electronic transitions and intermolecular forces

International Nuclear Information System (INIS)

Hemert, M.C. van.

1981-01-01

This thesis describes two different subjects - electronic transitions and intermolecular forces - that are related mainly by the following observation: The wavenumber at which an electronic transition in an atom or molecule occurs, depends on the environment of that atom or molecule. This implies, for instance, that when a molecule becomes solvated its absorption spectrum may be shifted either to the blue or to the red side of the original gasphase spectrum. In part I attention is paid to the experimental aspects of VUV spectroscopy, both in the gasphase and in the condensed phase. In part II a series of papers are presented, dealing with the calculation of intermolecular forces (and some related topics) both for the ground state and for the excited state interactions, using different non-empirical methods. The calculations provide, among other results, a semiquantitative interpretation of the spectral blue shifts encountered in our experiments. (Auth.)

Iron(II)-catalyzed intermolecular amino-oxygenation of olefins through the N-O bond cleavage of functionalized hydroxylamines.

Science.gov (United States)

Lu, Deng-Fu; Zhu, Cheng-Liang; Jia, Zhen-Xin; Xu, Hao

2014-09-24

An iron-catalyzed diastereoselective intermolecular olefin amino-oxygenation reaction is reported, which proceeds via an iron-nitrenoid generated by the N-O bond cleavage of a functionalized hydroxylamine. In this reaction, a bench-stable hydroxylamine derivative is used as the amination reagent and oxidant. This method tolerates a range of synthetically valuable substrates that have been all incompatible with existing amino-oxygenation methods. It can also provide amino alcohol derivatives with regio- and stereochemical arrays complementary to known amino-oxygenation methods.

Room temperature ionic liquids: A simple model. Effect of chain length and size of intermolecular potential on critical temperature.

Science.gov (United States)

Chapela, Gustavo A; Guzmán, Orlando; Díaz-Herrera, Enrique; del Río, Fernando

2015-04-21

A model of a room temperature ionic liquid can be represented as an ion attached to an aliphatic chain mixed with a counter ion. The simple model used in this work is based on a short rigid tangent square well chain with an ion, represented by a hard sphere interacting with a Yukawa potential at the head of the chain, mixed with a counter ion represented as well by a hard sphere interacting with a Yukawa potential of the opposite sign. The length of the chain and the depth of the intermolecular forces are investigated in order to understand which of these factors are responsible for the lowering of the critical temperature. It is the large difference between the ionic and the dispersion potentials which explains this lowering of the critical temperature. Calculation of liquid-vapor equilibrium orthobaric curves is used to estimate the critical points of the model. Vapor pressures are used to obtain an estimate of the triple point of the different models in order to calculate the span of temperatures where they remain a liquid. Surface tensions and interfacial thicknesses are also reported.

On the influence of the intermolecular potential on the wetting properties of water on silica surfaces

Science.gov (United States)

Pafong, E.; Geske, J.; Drossel, B.

2016-09-01

We study the wetting properties of water on silica surfaces using molecular dynamics (MD) simulations. To describe the intermolecular interaction between water and silica atoms, two types of interaction potential models are used: the standard BródkA and Zerda (BZ) model and the Gulmen and Thompson (GT) model. We perform an in-depth analysis of the influence of the choice of the potential on the arrangement of the water molecules in partially filled pores and on top of silica slabs. We find that at moderate pore filling ratios, the GT silica surface is completely wetted by water molecules, which agrees well with experimental findings, while the commonly used BZ surface is less hydrophilic and is only partially wetted. We interpret our simulation results using an analytical calculation of the phase diagram of water in partially filled pores. Moreover, an evaluation of the contact angle of the water droplet on top of the silica slab reveals that the interaction becomes more hydrophilic with increasing slab thickness and saturates around 2.5-3 nm, in agreement with the experimentally found value. Our analysis also shows that the hydroaffinity of the surface is mainly determined by the electrostatic interaction, but the van der Waals interaction nevertheless is strong enough that it can turn a hydrophobic surface into a hydrophilic surface.

Thz Spectroscopy and DFT Modeling of Intermolecular Vibrations in Hydrophobic Amino Acids

Science.gov (United States)

Williams, michael R. C.; Aschaffenburg, Daniel J.; Schmuttenmaer, Charles A.

2013-06-01

Vibrations that involve intermolecular displacements occur in molecular crystals at frequencies in the 0.5-5 THz range (˜15-165 cm^{-1}), and these motions are direct indicators of the interaction potential between the molecules. The intermolecular potential energy surface of crystalline hydrophobic amino acids is inherently interesting simply because of the wide variety of forces (electrostatic, dipole-dipole, hydrogen-bonding, van der Waals) that are present. Furthermore, an understanding of these particular interactions is immediately relevant to important topics like protein conformation and pharmaceutical polymorphism. We measured the low-frequency absorption spectra of several polycrystalline hydrophobic amino acids using THz time-domain spectroscopy, and in addition we carried out DFT calculations using periodic boundary conditions and an exchange-correlation functional that accounts for van der Waals dispersion forces. We chose to investigate a series of similar amino acids with closely analogous unit cells (leucine, isoleucine, and allo-isoleucine, in racemic or pseudo-racemic mixtures). This allows us to consider trends in the vibrational spectra as a function of small changes in molecular arrangement and/or crystal geometry. In this way, we gain confidence that peak assignments are not based on serendipitous similarities between calculated and observed features.

A general intermolecular force field based on tight-binding quantum chemical calculations

Science.gov (United States)

Grimme, Stefan; Bannwarth, Christoph; Caldeweyher, Eike; Pisarek, Jana; Hansen, Andreas

2017-10-01

A black-box type procedure is presented for the generation of a molecule-specific, intermolecular potential energy function. The method uses quantum chemical (QC) information from our recently published extended tight-binding semi-empirical scheme (GFN-xTB) and can treat non-covalently bound complexes and aggregates with almost arbitrary chemical structure. The necessary QC information consists of the equilibrium structure, Mulliken atomic charges, charge centers of localized molecular orbitals, and also of frontier orbitals and orbital energies. The molecular pair potential includes model density dependent Pauli repulsion, penetration, as well as point charge electrostatics, the newly developed D4 dispersion energy model, Drude oscillators for polarization, and a charge-transfer term. Only one element-specific and about 20 global empirical parameters are needed to cover systems with nuclear charges up to radon (Z = 86). The method is tested for standard small molecule interaction energy benchmark sets where it provides accurate intermolecular energies and equilibrium distances. Examples for structures with a few hundred atoms including charged systems demonstrate the versatility of the approach. The method is implemented in a stand-alone computer code which enables rigid-body, global minimum energy searches for molecular aggregation or alignment.

THz absorption spectrum of the CO2–H2O complex: Observation and assignment of intermolecular van der Waals vibrations

DEFF Research Database (Denmark)

Andersen, Jonas; Heimdal, J.; Wallin Mahler Andersen, Denise

2014-01-01

have been assigned and provide crucial observables for benchmark theoretical descriptions of this systems’ flat intermolecular potential energy surface. A (semi)-empirical value for the zero-point energy of 273 ± 15 cm−1 from the class of intermolecular van der Waals vibrations is proposed...... and the combination with high-level quantum chemical calculations provides a value of 726 ± 15 cm−1 for the dissociation energy D0...

Characterizing the Polymer:Fullerene Intermolecular Interactions

KAUST Repository

Sweetnam, Sean; Vandewal, Koen; Cho, Eunkyung; Risko, Chad; Coropceanu, Veaceslav; Salleo, Alberto; Bredas, Jean-Luc; McGehee, Michael D.

2016-01-01

the polymer and fullerene, there is not a consensus on the nature of these interactions. In this work, we use a combination of Raman spectroscopy, charge transfer state absorption, and density functional theory calculations to show that the intermolecular

Intermolecular cleavage by UmuD-like mutagenesis proteins

Science.gov (United States)

McDonald, John P.; Frank, Ekaterina G.; Levine, Arthur S.; Woodgate, Roger

1998-01-01

The activity of a number of proteins is regulated by self-processing reactions. Elegant examples are the cleavage of the prokaryotic LexA and λCI transcriptional repressors and the UmuD-like mutagenesis proteins. Various studies support the hypothesis that LexA and λCI cleavage reactions are predominantly intramolecular in nature. The recently described crystal structure of the Escherichia coli UmuD′ protein (the posttranslational cleavage product of the UmuD protein) suggests, however, that the region of the protein corresponding to the cleavage site is at least 50 Å away from the catalytic active site. We considered the possibility, therefore, that the UmuD-like proteins might undergo self-processing that, in contrast to LexA and λCI, occurs via an intermolecular rather than intramolecular reaction. To test this hypothesis, we introduced into E. coli compatible plasmids with mutations at either the cleavage or the catalytic site of three UmuD-like proteins. Cleavage of these proteins only occurs in the presence of both plasmids, indicating that the reaction is indeed intermolecular in nature. Furthermore, this intermolecular reaction is completely dependent upon the multifunctional RecA protein and leads to the restoration of cellular mutagenesis in nonmutable E. coli strains. Intermolecular cleavage of a biotinylated UmuD active site mutant was also observed in vitro in the presence of the wild-type UmuD′ protein, indicating that in addition to the intact UmuD protein, the normal cleavage product (UmuD′) can also act as a classical enzyme. PMID:9465040

Intermolecular cope-type hydroamination of alkenes and alkynes using hydroxylamines.

Science.gov (United States)

Moran, Joseph; Gorelsky, Serge I; Dimitrijevic, Elena; Lebrun, Marie-Eve; Bédard, Anne-Catherine; Séguin, Catherine; Beauchemin, André M

2008-12-31

The development of the Cope-type hydroamination as a method for the metal- and acid-free intermolecular hydroamination of hydroxylamines with alkenes and alkynes is described. Aqueous hydroxylamine reacts efficiently with alkynes in a Markovnikov fashion to give oximes and with strained alkenes to give N-alkylhydroxylamines, while unstrained alkenes are more challenging. N-Alkylhydroxylamines also display similar reactivity with strained alkenes and give modest to good yields with vinylarenes. Electron-rich vinylarenes lead to branched products while electron-deficient vinylarenes give linear products. A beneficial additive effect is observed with sodium cyanoborohydride, the extent of which is dependent on the structure of the hydroxylamine. The reaction conditions are found to be compatible with common protecting groups, free OH and NH bonds, as well as bromoarenes. Both experimental and theoretical results suggest the proton transfer step of the N-oxide intermediate is of vital importance in the intermolecular reactions of alkenes. Details are disclosed concerning optimization, reaction scope, limitations, and theoretical analysis by DFT, which includes a detailed molecular orbital description for the concerted hydroamination process and an exhaustive set of calculated potential energy surfaces for the reactions of various alkenes, alkynes, and hydroxylamines.

Observation of aggregation triggered by Resonance Energy Transfer (RET) induced intermolecular pairing force.

Science.gov (United States)

Pan, Xiaoyong; Wang, Weizhi; Ke, Lin; Zhang, Nan

2017-07-20

In this report, we showed the existence of RET induced intermolecular pairing force by comparing their fluorescence behaviors under room illumination vs standing in dark area for either PFluAnt solution or PFluAnt&PFOBT mixture. Their prominent emission attenuation under room illumination brought out the critical role of photo, i.e. RET induced intermolecular pairing force in induction of polymer aggregation. Constant UV-Vis absorption and fluorescence spectra in terms of both peak shapes and maximum wavelengths implied no chemical decomposition was involved. Recoverable fluorescence intensity, fluorescence lifetime as well as NMR spectra further exclude photo induced decomposition. The controllable on/off state of RET induced intermolecular pairing force was verified by the masking effect of outside PFluAnt solution which function as filter to block the excitation of inside PFluAnt and thus off the RET induced intermolecular pairing force. Theoretical calculation suggest that magnitude of RET induced intermolecular pairing force is on the same scale as that of van der Waals interaction. Although the absolute magnitude of RET induced intermolecular pairing force was not tunable, its effect can be magnified by intentionally turn it "on", which was achieved by irradiance with 5 W desk lamp in this report.

Rubrene: The interplay between intramolecular and intermolecular interactions determines the planarization of its tetracene core in the solid state

KAUST Repository

Sutton, Christopher

2015-06-15

Rubrene is one of the most studied molecular semiconductors; its chemical structure consists of a tetracene backbone with four phenyl rings appended to the two central fused rings. Derivatization of these phenyl rings can lead to two very different solid-state molecular conformations and packings: One in which the tetracene core is planar and there exists substantive overlap among neighboring π-conjugated backbones; and another where the tetracene core is twisted and the overlap of neighboring π-conjugated backbones is completely disrupted. State-of-the-art electronic-structure calculations show for all isolated rubrene derivatives that the twisted conformation is more favorable (by -1.7 to -4.1 kcal mol-1), which is a consequence of energetically unfavorable exchange-repulsion interactions among the phenyl side groups. Calculations based on available crystallographic structures reveal that planar conformations of the tetracene core in the solid state result from intermolecular interactions that can be tuned through well-chosen functionalization of the phenyl side groups, and lead to improved intermolecular electronic couplings. Understanding the interplay of these intramolecular and intermolecular interactions provides insight into how to chemically modify rubrene and similar molecular semiconductors to improve the intrinsic materials electronic properties.

Quantitative analysis of intermolecular interactions in orthorhombic rubrene

Directory of Open Access Journals (Sweden)

Venkatesha R. Hathwar

2015-09-01

Full Text Available Rubrene is one of the most studied organic semiconductors to date due to its high charge carrier mobility which makes it a potentially applicable compound in modern electronic devices. Previous electronic device characterizations and first principles theoretical calculations assigned the semiconducting properties of rubrene to the presence of a large overlap of the extended π-conjugated core between molecules. We present here the electron density distribution in rubrene at 20 K and at 100 K obtained using a combination of high-resolution X-ray and neutron diffraction data. The topology of the electron density and energies of intermolecular interactions are studied quantitatively. Specifically, the presence of Cπ...Cπ interactions between neighbouring tetracene backbones of the rubrene molecules is experimentally confirmed from a topological analysis of the electron density, Non-Covalent Interaction (NCI analysis and the calculated interaction energy of molecular dimers. A significant contribution to the lattice energy of the crystal is provided by H—H interactions. The electron density features of H—H bonding, and the interaction energy of molecular dimers connected by H—H interaction clearly demonstrate an importance of these weak interactions in the stabilization of the crystal structure. The quantitative nature of the intermolecular interactions is virtually unchanged between 20 K and 100 K suggesting that any changes in carrier transport at these low temperatures would have a different origin. The obtained experimental results are further supported by theoretical calculations.

The Raman and vibronic activity of intermolecular vibrations in aromatic-containing complexes and clusters

International Nuclear Information System (INIS)

Maxton, P.M.; Schaeffer, M.W.; Ohline, S.M.; Kim, W.; Venturo, V.A.; Felker, P.M.

1994-01-01

Theoretical and experimental results pertaining to the excitation of intermolecular vibrations in the Raman and vibronic spectra of aromatic-containing, weakly bound complexes and clusters are reported. The theoretical analysis of intermolecular Raman activity is based on the assumption that the polarizability tensor of a weakly bound species is given by the sum of the polarizability tensors of its constituent monomers. The analysis shows that the van der Waals bending fundamentals in aromatic--rare gas complexes may be expected to be strongly Raman active. More generally, it predicts strong Raman activity for intermolecular vibrations that involve the libration or internal rotation of monomer moieties having appreciable permanent polarizability anisotropies. The vibronic activity of intermolecular vibrations in aromatic-rare gas complexes is analyzed under the assumption that every vibronic band gains its strength from an aromatic-localized transition. It is found that intermolecular vibrational excitations can accompany aromatic-localized vibronic excitations by the usual Franck--Condon mechanism or by a mechanism dependent on the librational amplitude of the aromatic moiety during the course of the pertinent intermolecular vibration. The latter mechanism can impart appreciable intensity to bands that are forbidden by rigid-molecule symmetry selection rules. The applicability of such rules is therefore called into question. Finally, experimental spectra of intermolecular transitions, obtained by mass-selective, ionization-detected stimulated Raman spectroscopies, are reported for benzene--X (X=Ar, --Ar 2 , N 2 , HCl, CO 2 , and --fluorene), fluorobenzene--Ar and --Kr, aniline--Ar, and fluorene--Ar and --Ar 2 . The results support the conclusions of the theoretical analyses and provide further evidence for the value of Raman methods in characterizing intermolecular vibrational level structures

Intermolecular failure of L-type Ca2+ channel and ryanodine receptor signaling in hypertrophy.

Directory of Open Access Journals (Sweden)

Ming Xu

2007-02-01

Full Text Available Pressure overload-induced hypertrophy is a key step leading to heart failure. The Ca(2+-induced Ca(2+ release (CICR process that governs cardiac contractility is defective in hypertrophy/heart failure, but the molecular mechanisms remain elusive. To examine the intermolecular aspects of CICR during hypertrophy, we utilized loose-patch confocal imaging to visualize the signaling between a single L-type Ca(2+ channel (LCC and ryanodine receptors (RyRs in aortic stenosis rat models of compensated (CHT and decompensated (DHT hypertrophy. We found that the LCC-RyR intermolecular coupling showed a 49% prolongation in coupling latency, a 47% decrease in chance of hit, and a 72% increase in chance of miss in DHT, demonstrating a state of "intermolecular failure." Unexpectedly, these modifications also occurred robustly in CHT due at least partially to decreased expression of junctophilin, indicating that intermolecular failure occurs prior to cellular manifestations. As a result, cell-wide Ca(2+ release, visualized as "Ca(2+ spikes," became desynchronized, which contrasted sharply with unaltered spike integrals and whole-cell Ca(2+ transients in CHT. These data suggested that, within a certain limit, termed the "stability margin," mild intermolecular failure does not damage the cellular integrity of excitation-contraction coupling. Only when the modification steps beyond the stability margin does global failure occur. The discovery of "hidden" intermolecular failure in CHT has important clinical implications.

Intermolecular interactions between σ- and π-holes of bromopentafluorobenzene and pyridine: computational and experimental investigations.

Science.gov (United States)

Yang, Fang-Ling; Yang, Xing; Wu, Rui-Zhi; Yan, Chao-Xian; Yang, Fan; Ye, Weichun; Zhang, Liang-Wei; Zhou, Pan-Pan

2018-04-25

The characters of σ- and π-holes of bromopentafluorobenzene (C6F5Br) enable it to interact with an electron-rich atom or group like pyridine which possesses an electron lone-pair N atom and a π ring. Theoretical studies of intermolecular interactions between C6F5Br and C5H5N have been carried out at the M06-2X/aug-cc-pVDZ level without and with the counterpoise method, together with single point calculations at M06-2X/TZVP, wB97-XD/aug-cc-pVDZ and CCSD(T)/aug-cc-pVDZ levels. The σ- and π-holes of C6F5Br exhibiting positive electrostatic potentials make these sites favorably interact with the N atom and the π ring of C5H5N with negative electrostatic potentials, leading to five different dimers connected by a σ-holen bond, a σ-holeπ bond or a π-holeπ bond. Their geometrical structures, characteristics, nature and spectroscopy behaviors were systematically investigated. EDA analyses reveal that the driving forces in these dimers are different. NCI, QTAIM and NBO analyses confirm the existence of intermolecular interactions formed via σ- and π-holes of C6F5Br and the N atom and the π ring of C5H5N. The experimental IR and Raman spectra gave us important information about the formation of molecular complexes between C6F5Br and C5H5N. We expect that the results could provide valuable insights into the investigation of intermolecular interactions involving σ- and π-holes.

Intermolecular Interactions and Cooperative Effects from Electronic Structure Calculations: An Effective Means for Developing Interaction Potentials for Condensed Phase Simulations

Energy Technology Data Exchange (ETDEWEB)

Xantheas, Sotiris S.

2004-05-01

The modeling of the macroscopic properties of homogeneous and inhomogeneous systems via atomistic simulations such as molecular dynamics (MD) or Monte Carlo (MC) techniques is based on the accurate description of the relevant solvent-solute and solvent-solvent intermolecular interactions. The total energy (U) of an n-body molecular system can be formally written as [1,2,3

Programmable display of DNA-protein chimeras for controlling cell-hydrogel interactions via reversible intermolecular hybridization.

Science.gov (United States)

Zhang, Zhaoyang; Li, Shihui; Chen, Niancao; Yang, Cheng; Wang, Yong

2013-04-08

Extensive studies have been recently carried out to achieve dynamic control of cell-material interactions primarily through physicochemical stimulation. The purpose of this study was to apply reversible intermolecular hybridization to program cell-hydrogel interactions in physiological conditions based on DNA-antibody chimeras and complementary oligonucleotides. The results showed that DNA oligonucleotides could be captured to and released from the immobilizing DNA-functionalized hydrogels with high specificity via DNA hybridization. Accordingly, DNA-antibody chimeras were captured to the hydrogels, successfully inducing specific cell attachment. The cell attachment to the hydrogels reached the plateau at approximately half an hour after the functionalized hydrogels and the cells were incubated together. The attached cells were rapidly released from the bound hydrogels when triggering complementary oligonucleotides were introduced to the system. However, the capability of the triggering complementary oligonucleotides in releasing cells was affected by the length of intermolecular hybridization. The length needed to be at least more than 20 base pairs in the current experimental setting. Notably, because the procedure of intermolecular hybridization did not involve any harsh condition, the released cells maintained the same viability as that of the cultured cells. The functionalized hydrogels also exhibited the potential to catch and release cells repeatedly. Therefore, this study demonstrates that it is promising to regulate cell-material interactions dynamically through the DNA-programmed display of DNA-protein chimeras.

Multi-property isotropic intermolecular potentials and predicted spectral lineshapes of collision-induced absorption (CIA), collision-induced light scattering (CILS) and collision-induced hyper-Rayleigh scattering (CIHR) for H2sbnd Ne, -Kr and -Xe

Science.gov (United States)

El-Kader, M. S. A.; Godet, J.-L.; Gustafsson, M.; Maroulis, G.

2018-04-01

Quantum mechanical lineshapes of collision-induced absorption (CIA), collision-induced light scattering (CILS) and collision-induced hyper-Rayleigh scattering (CIHR) at room temperature (295 K) are computed for gaseous mixtures of molecular hydrogen with neon, krypton and xenon. The induced spectra are detected using theoretical values for induced dipole moment, pair-polarizability trace and anisotropy, hyper-polarizability and updated intermolecular potentials. Good agreement is observed for all spectra when the literature and the present potentials which are constructed from the transport and thermo-physical properties are used.

Cohesion: a scientific history of intermolecular forces

National Research Council Canada - National Science Library

Rowlinson, J. S

2002-01-01

.... The final section gives an account of the successful use in the 20th century of quantum mechanics and statistical mechanics to resolve most of the remaining problems. Throughout the last 300 years there have been periods of tremendous growth in our understanding of intermolecular forces but such interest proved to be unsustainable, and long periods of...

The iodine molecule insights into intra- and intermolecular perturbation in diatomic molecules

CERN Document Server

Lukashov, Sergey; Pravilov, Anatoly

2018-01-01

This book presents experimental and theoretical spectroscopic studies performed over the last 25 years on the iodine molecule’s excited states and their perturbations. It is going to be of interest to researchers who study intra- and intermolecular perturbations in diatomic molecules and more complex systems. The book offers a detailed treatment of the nonadiabatic perturbations of valence, ion pair and Rydberg states induced by intramolecular as well as intermolecular interactions in collisions or in weakly-bound complexes. It also provides an overview of current instrumentation and techniques as well as theoretical approaches describing intra- and intermolecular perturbations. The authors are experts in the use of spectroscopy for the study of intrinsic and collision-induced perturbations in diatomic iodine. They introduced new methods of two- and three-step optical population of the iodine ion-pair states. The iodine molecule has 23 valence states correlating with three dissociation limits, 20 so-called ...

Influence of pressure on the crystallization of systems characterized by different intermolecular attraction

Science.gov (United States)

Koperwas, K.; Affouard, F.; Gerges, J.; Valdes, L.-C.; Adrjanowicz, K.; Paluch, M.

2017-12-01

In this paper, we examine, in terms of the classical nucleation theory, how the strengthening of the attractive intermolecular interactions influences the crystallization process for systems like Lennard-Jones at different isobaric conditions. For this purpose, we modify the standard Lennard-Jones potential, and as a result, we obtain three different systems characterized by various strengths of attractive potentials occurring between molecules, which are in direct relationship to the physical quantities describing molecules, e.g., its polarizability or dipole moment. Based on performed analysis, we demonstrate that the molecular attraction primarily impacts the thermodynamics of the interface between liquid and crystal. This is reflected in the behavior of nucleation and overall crystallization rates during compression of the system.

Orientation correlation and intermolecular structure of GeCl4, VCl4 and other tetrachloride liquids

International Nuclear Information System (INIS)

Nath, P.P.; Sarkar, S.; Joarder, R.N.

2007-01-01

The intermolecular structure and correlation of GeCl 4 , VCl 4 and other tetrachloride liquids can be well described by Misawa's orientation correlation model originally applied to liquid CCl 4 . The model supports on average a specific 'corner' to 'face' correlation, but evidently very different from 'Apollo' type model. The Misawa model appears to work, in some respect, even better than reference interaction site model (RISM) used for long to describe intermolecular structure of such molecular systems. The test and comparison are made through the calculation of small asymmetric part of the intermolecular structure and evaluation of partial atom-atom distribution functions

Dancing Crystals: A Dramatic Illustration of Intermolecular Forces

Science.gov (United States)

Mundell, Donald W.

2007-01-01

Crystals of naphthalene form on the surface of an acetone solution and dance about in an animated fashion illustrating surface tension, crystallization, and intermolecular forces. Additional experiments reveal the properties of the solution. Flows within the solutions can be visualized by various means. Previous demonstrations of surface motion…

Phase transitions in liquids with directed intermolecular bonding

OpenAIRE

Son, L.; Ryltcev, R.

2005-01-01

Liquids with quasi - chemical bonding between molecules are described in terms of vertex model. It is shown that this bonding results in liquid - liquid phase transition, which occurs between phases with different mean density of intermolecular bonds. The transition may be suggested to be a universal phenomena for those liquids.

Intermolecular spectroscopy

International Nuclear Information System (INIS)

Gelbart, W.M.

1980-01-01

In this article some of the theoretical background is presented for the following papers on 'Intermolecular Spectroscopy and Dynamical Properties of Dense Systems'. In Section 1 we outline a simple semi-classical description of the interaction between optical radiation and matter. The motion of a many-body polarizability is introduced; limiting forms of this complicated quantity lead to the familiar cases of light scattering spectra. In Section 2 we consider the linear response approximation, and the equation of motion for the many-body density matrix is solved to first order in the matter-radiation interaction. The often quoted fluctuation-dissipation theorem and the time-dependent, equilibrium correlation functions are discussed. Section 3 treats the problem of the local field. In Section 4 we consider the special case of collision-induced light scattering by atomic fluids in the low-density limit. This allows us to focus on determining the interaction polarizability for simple gases. Finally, in Section 5 we distinguish between collision-induced and multiple light scattering, and discuss the double-light-scattering analyses which provide new information about critical and thermodynamically unstable fluids. (KBE)

Digital communication through intermolecular fluorescence modulation.

Science.gov (United States)

Raymo, F M; Giordani, S

2001-06-14

[see reaction]. Ultraminiaturized processors incorporating molecular components can be developed only after devising efficient strategies to communicate signals at the molecular level. We have demonstrated that a three-state molecular switch responds to ultraviolet light, visible light, and H+, attenuating the emission intensity of a fluorescent probe. Intermolecular communication is responsible for the transduction of three input signals into a single optical output. The behavior of the communicating ensemble of molecules corresponds to that of a logic circuit incorporating seven gates.

Controlled Self-Assembly of Low-Dimensional Alq3 Nanostructures from 1D Nanowires to 2D Plates via Intermolecular Interactions

Science.gov (United States)

Gu, Jianmin; Yin, Baipeng; Fu, Shaoyan; Jin, Cuihong; Liu, Xin; Bian, Zhenpan; Li, Jianjun; Wang, Lu; Li, Xiaoyu

2018-03-01

Due to the intense influence of the shape and size of the photon building blocks on the limitation and guidance of optical waves, an important strategy is the fabrication of different structures. Herein, organic semiconductor tris-(8-hydroxyquinoline)aluminium (Alq3) nanostructures with controllable morphology, ranging from one-dimensional nanowires to two-dimensional plates, have been prepared through altering intermolecular interactions with employing the anti-solvent diffusion cooperate with solvent-volatilization induced self-assembly method. The morphologies of the formed nanostructures, which are closely related to the stacking modes of the molecules, can be exactly controlled by altering the polarity of anti-solvents that can influence various intermolecular interactions. The synthesis strategy reported here can potentially be extended to other functional organic nanomaterials.

Symmetry in the polarization expansion for intermolecular forces

International Nuclear Information System (INIS)

Chipman, D.M.; Hirschfelder, J.O.

1980-01-01

In the usual polarization expansion for intermolecular forces, exchange effects that determine the separations of energy levels within the manifold of interacting states are ignored. Previous low order calculations on simple physical systems have indicated that these exchange terms can be described reasonably well by an appropriate ad hoc symmetrization of the polarization wave function (the SYM-P method). But theoretical considerations suggest that the SYM-P method should be good for only one of the interacting states and not for the others in the manifold. Here this long standing apparent conflict between theoretical expectations and actual results is explained by consideration of a simple model system in which the relevant equations can be solved exactly. It is concluded that while the SYM-P method is potentially exact for only one of the interacting states, it may provide good approximations to the other states of the manifold in the case of large separations of the interacting subsystems

Effect of intermolecular cohesion on coal liquefaction. 3. Reactivity of oxygen methylated coal; Sekitan teibunshika hanno ni okeru bunshikan gyoshuryoku no koka. 3. O-methyl ka tan no hanno tokusei

Energy Technology Data Exchange (ETDEWEB)

Sasaki, M.; Nagaishi, H.; Yoshida, T. [Hokkaido National Industrial Research Institute, Sapporo (Japan)

1996-10-28

The reactivity of oxygen methylated coal was studied to control hydrogen bond in bituminous coal liquefaction and intermolecular cohesion such as van der Waals force. In experiment, crushed and dried Illinois coal of 100mesh or less was used as specimen, and oxygen methylated coal was prepared by Liotta`s method using tetrabutylammonium halide. Coal liquefaction was conducted in an electromagnetic agitation autoclave using tetralin solvent under initial hydrogen pressure of 100kg/cm{sup 2} while heating. The molecular weight distribution of the products obtained was measured by gel permeation chromatography (GPC) analysis. The experimental results are as follows. The effect of intermolecular cohesion in bituminous coal on the reactivity is mainly derived from decomposing reaction from preasphaltene to oil. Yields of oil fraction by methylation increase corresponding to release of intermolecular cohesion. Since the thermal release is promoted with temperature rise, the difference in yield due to different treatments decreases. 5 refs., 3 figs., 1 tab.

Intermolecular interactions in the condensed phase

DEFF Research Database (Denmark)

Christensen, Anders S.; Kromann, Jimmy Charnley; Jensen, Jan Halborg

2017-01-01

To facilitate further development of approximate quantum mechanical methods for condensed phase applications, we present a new benchmark dataset of intermolecular interaction energies in the solution phase for a set of 15 dimers, each containing one charged monomer. The reference interaction energy...... and solution phases. As most approximate QM methods are parametrized and evaluated using data measured or calculated in the gas phase, the dataset represents an important first step toward calibrating QM based methods for application in the condensed phase where polarization and exchange repulsion need...

Effect of intermolecular hydrogen bonding, vibrational analysis and molecular structure of 4-chlorobenzothioamide

Science.gov (United States)

Çırak, Çağrı; Sert, Yusuf; Ucun, Fatih

2013-09-01

In the present work, the experimental and theoretical vibrational spectra of 4-chlorobenzothioamide were investigated. The FT-IR (400-4000 cm-1) and μ-Raman spectra (100-4000 cm-1) of 4-chlorobenzothioamide in the solid phase were recorded. The geometric parameters (bond lengths and bond angles), vibrational frequencies, Infrared and Raman intensities of the title molecule in the ground state were calculated using ab initio Hartree-Fock and density functional theory (B3LYP) methods with the 6-311++G(d,p) basis set for the first time. The optimized geometric parameters and the theoretical vibrational frequencies were found to be in good agreement with the corresponding experimental data and with the results found in the literature. The vibrational frequencies were assigned based on the potential energy distribution using the VEDA 4 program. The dimeric form of 4-chlorobenzothioamide was also simulated to evaluate the effect of intermolecular hydrogen bonding on the vibrational frequencies. It was observed that the Nsbnd H stretching modes shifted to lower frequencies, while the in-plane and out-of-plane bending modes shifted to higher frequencies due to the intermolecular Nsbnd H⋯S hydrogen bond. Also, the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies and diagrams were presented.

Decomposition of Intermolecular Interactions in the Crystal Structure of Some Diacetyl Platinum(II Complexes: Combined Hirshfeld, AIM, and NBO Analyses

Directory of Open Access Journals (Sweden)

Saied M. Soliman

2016-12-01

Full Text Available Intermolecular interactions play a vital role in crystal structures. Therefore, we conducted a topological study, using Hirshfeld surfaces and atom in molecules (AIM analysis, to decompose and analyze, respectively, the different intermolecular interactions in six hydrazone-diacetyl platinum(II complexes. Using AIM and natural bond orbital (NBO analyses, we determined the type, nature, and strength of the interactions. All the studied complexes contain C-H⋯O interactions, and the presence of bond critical points along the intermolecular paths underlines their significance. The electron densities (ρ(r at the bond critical points (0.0031–0.0156 e/a03 fall within the typical range for H-bonding interactions. Also, the positive values of the Laplacian of the electron density (∇2ρ(r revealed the depletion of electronic charge on the interatomic path, another characteristic feature of closed-shell interactions. The ratios of the absolute potential energy density to the kinetic energy density (|V(r|/G(r and ρ(r are highest for the O2⋯H15-N3 interaction in [Pt(COMe2(2-pyCMe=NNH2] (1; hence, this interaction has the highest covalent character of all the O⋯H intermolecular interactions. Interestingly, in [Pt(COMe2(H2NN=CMe-CMe=NNH2] (3, there are significant N-H⋯Pt interactions. Using the NBO method, the second-order interaction energies, E(2, of these interactions range from 3.894 to 4.061 kJ/mol. Furthermore, the hybrid Pt orbitals involved in these interactions are comprised of dxy, dxz, and s atomic orbitals.

Study of intermolecular interactions in binary mixtures of ethanol in methanol

Science.gov (United States)

Maharolkar, Aruna P.; Khirade, P. W.; Murugkar, A. G.

2016-05-01

Present paper deals with study of physicochemical properties like viscosity, density and refractive index for the binary mixtures of ethanol and methanol over the entire concentration range were measured at 298.15 K. The experimental data further used to determine the excess properties viz. excess molar volume, excess viscosity, excess molar refraction. The values of excess properties further fitted with Redlich-Kister (R-K Fit) equation to calculate the binary coefficients and standard deviation. The resulting excess parameters are used to indicate the presence of intermolecular interactions and strength of intermolecular interactions between the molecules in the binary mixtures. Excess parameters indicate structure making factor in the mixture predominates in the system.

Derivative discontinuity with localized Hartree-Fock potential

Energy Technology Data Exchange (ETDEWEB)

Nazarov, V. U. [Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan (China); Vignale, G. [Department of Physics, University of Missouri-Columbia, Columbia, Missouri 65211 (United States)

2015-08-14

The localized Hartree-Fock potential has proven to be a computationally efficient alternative to the optimized effective potential, preserving the numerical accuracy of the latter and respecting the exact properties of being self-interaction free and having the correct −1/r asymptotics. In this paper we extend the localized Hartree-Fock potential to fractional particle numbers and observe that it yields derivative discontinuities in the energy as required by the exact theory. The discontinuities are numerically close to those of the computationally more demanding Hartree-Fock method. Our potential enjoys a “direct-energy” property, whereby the energy of the system is given by the sum of the single-particle eigenvalues multiplied by the corresponding occupation numbers. The discontinuities c{sub ↑} and c{sub ↓} of the spin-components of the potential at integer particle numbers N{sub ↑} and N{sub ↓} satisfy the condition c{sub ↑}N{sub ↑} + c{sub ↓}N{sub ↓} = 0. Thus, joining the family of effective potentials which support a derivative discontinuity, but being considerably easier to implement, the localized Hartree-Fock potential becomes a powerful tool in the broad area of applications in which the fundamental gap is an issue.

Alkylation of Zwitterionic Thiooxalic Acid Derivatives

Directory of Open Access Journals (Sweden)

Manfred Michalik

2001-05-01

Full Text Available The new S-alkyl thiooxal-1-hydrazono-2-amidrazonium halides 2-4 were synthesized by reaction of the corresponding zwitterionic thiooxalic acid derivatives 1 with alkyl halides in methanol. The structures of compounds 4b and 4d were proven by X-ray structural analysis. Both compounds form an interesting intermolecular network of hydrogen bonds in the solid state.

Lack of evidence for intermolecular epistatic interactions between adiponectin and resistin gene polymorphisms in Malaysian male subjects

Directory of Open Access Journals (Sweden)

Cia-Hin Lau

2012-01-01

Full Text Available Epistasis (gene-gene interaction is a ubiquitous component of the genetic architecture of complex traits such as susceptibility to common human diseases. Given the strong negative correlation between circulating adiponectin and resistin levels, the potential intermolecular epistatic interactions between ADIPOQ (SNP+45T > G, SNP+276G > T, SNP+639T > C and SNP+1212A > G and RETN (SNP-420C > G and SNP+299G > A gene polymorphisms in the genetic risk underlying type 2 diabetes (T2DM and metabolic syndrome (MS were assessed. The potential mutual influence of the ADIPOQ and RETN genes on their adipokine levels was also examined. The rare homozygous genotype (risk alleles of SNP-420C > G at the RETN locus tended to be co-inherited together with the common homozygous genotypes (protective alleles of SNP+639T > C and SNP+1212A > G at the ADIPOQ locus. Despite the close structural relationship between the ADIPOQ and RETN genes, there was no evidence of an intermolecular epistatic interaction between these genes. There was also no reciprocal effect of the ADIPOQ and RETN genes on their adipokine levels, i.e., ADIPOQ did not affect resistin levels nor did RETN affect adiponectin levels. The possible influence of the ADIPOQ gene on RETN expression warrants further investigation.

Intermolecular Modes between LH2 Bacteriochlorophylls and Protein Residues: The Effect on the Excitation Energies.

Science.gov (United States)

Anda, André; De Vico, Luca; Hansen, Thorsten

2017-06-08

Light-harvesting system 2 (LH2) executes the primary processes of photosynthesis in purple bacteria; photon absorption, and energy transportation to the reaction center. A detailed mechanistic insight into these operations is obscured by the complexity of the light-harvesting systems, particularly by the chromophore-environment interaction. In this work, we focus on the effects of the protein residues that are ligated to the bacteriochlorophylls (BChls) and construct potential energy surfaces of the ground and first optically excited state for the various BChl-residue systems where we in each case consider two degrees of freedom in the intermolecular region. We find that the excitation energies are only slightly affected by the considered modes. In addition, we see that axial ligands and hydrogen-bonded residues have opposite effects on both excitation energies and oscillator strengths by comparing to the isolated BChls. Our results indicate that only a small part of the chromophore-environment interaction can be associated with the intermolecular region between a BChl and an adjacent residue, but that it may be possible to selectively raise or lower the excitation energy at the axial and planar residue positions, respectively.

Effects of pair correlation functions on intermolecular nuclear relaxation by translational and rotational diffusion in liquids

International Nuclear Information System (INIS)

Fries, P.

1978-01-01

In order to study the intermolecular relaxation due to magnetic dipolar interactions, we calculate the spectral densities resulting from random translational and rotational motions of spherical molecules carrying off-centre spins. The relative translational motion is treated in the frame-work of a general diffusion equation (the Smoluchowski equation) which takes into account the existence of effective forces between the molecules. This model implies a pair correlation function. i.e. a non unifom relative distribution of the molecules. The analytical calculations are carried out by taking correctly into account the hard sphere boundary conditions for the molecules. Explicit numerical calculations of the spectral densities are performed using finite difference methods and the pair correlation function of Verlet and Weiss obtained by computer experiments. The resulting calculations allow one to interpret the relaxation exhibited by benzene and some of its monohalogen derivatives which has been measured by Jonas et al. at various pressures. The effects of pair correlation and eccentricity contribute to a noticeable enhancement of the spectral densities, especially as the frequency increases. The translational correlation times calculated from the Stokes formula and those deduced from intermolecular relaxation studies are compared. It is shown that in order to distinguish which of the dynamical models is appropriate, measurements must be made as a function of frequency [fr

Kinetics of dihydro-dibenz[b,f]azepine derivatives sublimation

International Nuclear Information System (INIS)

Krongauz, V.V.; Ling, M.T.K.; Woo, L.; Purohit, U.

2007-01-01

Sublimation of dihydro-dibenz[b,f]azepine derivatives upon heating was studied and confirmed by thermogravimetry (TGA) and differential scanning calorimetry (DSC). DSC was used to analyze thermodynamics of melting. The kinetics of dihydro-dibenz[b,f]azepine derivatives sublimation were monitored by TGA as a function of temperature. Activation energies of sublimation were deduced and correlated with melting enthalpies and molecular structure. The results indicated that the sublimation was controlled by intermolecular forces in the crystalline lattice of dihydro-dibenz[b,f]azepine derivatives

Newtonian potential and geodesic completeness in infinite derivative gravity

Science.gov (United States)

Edholm, James; Conroy, Aindriú

2017-08-01

Recent study has shown that a nonsingular oscillating potential—a feature of infinite derivative gravity theories—matches current experimental data better than the standard General Relativity potential. In this work, we show that this nonsingular oscillating potential can be given by a wider class of theories which allows the defocusing of null rays and therefore geodesic completeness. We consolidate the conditions whereby null geodesic congruences may be made past complete, via the Raychaudhuri equation, with the requirement of a nonsingular Newtonian potential in an infinite derivative gravity theory. In doing so, we examine a class of Newtonian potentials characterized by an additional degree of freedom in the scalar propagator, which returns the familiar potential of General Relativity at large distances.

Structural variability and the nature of intermolecular interactions in Watson-Crick B-DNA base pairs.

Science.gov (United States)

Czyznikowska, Z; Góra, R W; Zaleśny, R; Lipkowski, P; Jarzembska, K N; Dominiak, P M; Leszczynski, J

2010-07-29

A set of nearly 100 crystallographic structures was analyzed using ab initio methods in order to verify the effect of the conformational variability of Watson-Crick guanine-cytosine and adenine-thymine base pairs on the intermolecular interaction energy and its components. Furthermore, for the representative structures, a potential energy scan of the structural parameters describing mutual orientation of the base pairs was carried out. The results were obtained using the hybrid variational-perturbational interaction energy decomposition scheme. The electron correlation effects were estimated by means of the second-order Møller-Plesset perturbation theory and coupled clusters with singles and doubles method adopting AUG-cc-pVDZ basis set. Moreover, the characteristics of hydrogen bonds in complexes, mimicking those appearing in B-DNA, were evaluated using topological analysis of the electron density. Although the first-order electrostatic energy is usually the largest stabilizing component, it is canceled out by the associated exchange repulsion in majority of the studied crystallographic structures. Therefore, the analyzed complexes of the nucleic acid bases appeared to be stabilized mainly by the delocalization component of the intermolecular interaction energy which, in terms of symmetry adapted perturbation theory, encompasses the second- and higher-order induction and exchange-induction terms. Furthermore, it was found that the dispersion contribution, albeit much smaller in terms of magnitude, is also a vital stabilizing factor. It was also revealed that the intermolecular interaction energy and its components are strongly influenced by four (out of six) structural parameters describing mutual orientation of bases in Watson-Crick pairs, namely shear, stagger, stretch, and opening. Finally, as a part of a model study, much of the effort was devoted to an extensive testing of the UBDB databank. It was shown that the databank quite successfully reproduces the

Boiling points of halogenated ethanes: an explanatory model implicating weak intermolecular hydrogen-halogen bonding.

Science.gov (United States)

Beauchamp, Guy

2008-10-23

This study explores via structural clues the influence of weak intermolecular hydrogen-halogen bonds on the boiling point of halogenated ethanes. The plot of boiling points of 86 halogenated ethanes versus the molar refraction (linked to polarizability) reveals a series of straight lines, each corresponding to one of nine possible arrangements of hydrogen and halogen atoms on the two-carbon skeleton. A multiple linear regression model of the boiling points could be designed based on molar refraction and subgroup structure as independent variables (R(2) = 0.995, standard error of boiling point 4.2 degrees C). The model is discussed in view of the fact that molar refraction can account for approximately 83.0% of the observed variation in boiling point, while 16.5% could be ascribed to weak C-X...H-C intermolecular interactions. The difference in the observed boiling point of molecules having similar molar refraction values but differing in hydrogen-halogen intermolecular bonds can reach as much as 90 degrees C.

Chemical origin of blue- and redshifted hydrogen bonds: intramolecular hyperconjugation and its coupling with intermolecular hyperconjugation.

Science.gov (United States)

Li, An Yong

2007-04-21

Upon formation of a H bond Y...H-XZ, intramolecular hyperconjugation n(Z)-->sigma*(X-H) of the proton donor plays a key role in red- and blueshift characters of H bonds and must be introduced in the concepts of hyperconjugation and rehybridization. Intermolecular hyperconjugation transfers electron density from Y to sigma*(X-H) and causes elongation and stretch frequency redshift of the X-H bond; intramolecular hyperconjugation couples with intermolecular hyperconjugation and can adjust electron density in sigma*(X-H); rehybridization causes contraction and stretch frequency blueshift of the X-H bond on complexation. The three factors--intra- and intermolecular hyperconjugations and rehybridization--determine commonly red- or blueshift of the formed H bond. A proton donor that has strong intramolecular hyperconjugation often forms blueshifted H bonds.

Gold-catalyzed intermolecular coupling of sulfonylacetylene with allyl ethers: [3,3]- and [1,3]-rearrangements

Directory of Open Access Journals (Sweden)

Jungho Jun

2013-08-01

Full Text Available Gold-catalyzed intermolecular couplings of sulfonylacetylenes with allyl ethers are reported. A cooperative polarization of alkynes both by a gold catalyst and a sulfonyl substituent resulted in an efficient intermolecular tandem carboalkoxylation. Reactions of linear allyl ethers are consistent with the [3,3]-sigmatropic rearrangement mechanism, while those of branched allyl ethers provided [3,3]- and [1,3]-rearrangement products through the formation of a tight ion–dipole pair.

Singlet Fission via an Excimer-Like Intermediate in 3,6-Bis(thiophen-2-yl)diketopyrrolopyrrole Derivatives.

Science.gov (United States)

Mauck, Catherine M; Hartnett, Patrick E; Margulies, Eric A; Ma, Lin; Miller, Claire E; Schatz, George C; Marks, Tobin J; Wasielewski, Michael R

2016-09-14

Singlet fission (SF) in polycrystalline thin films of four 3,6-bis(thiophen-2-yl)diketopyrrolopyrrole (TDPP) chromophores with methyl (Me), n-hexyl (C6), triethylene glycol (TEG), and 2-ethylhexyl (EH) substituents at the 2,5-positions is found to involve an intermediate excimer-like state. The four different substituents yield four distinct intermolecular packing geometries, resulting in variable intermolecular charge transfer (CT) interactions in the solid. SF from the excimer state of Me, C6, TEG, and EH takes place in τSF = 22, 336, 195, and 1200 ps, respectively, to give triplet yields of 200%, 110%, 110%, and 70%, respectively. The transient spectra of the excimer-like state and its energetic proximity to the lowest excited singlet state in these derivatives suggests that this state may be the multiexciton (1)(T1T1) state that precedes formation of the uncorrelated triplet excitons. The excimer decay rates correlate well with the SF efficiencies and the degree of intermolecular donor-acceptor interactions resulting from π-stacking of the thiophene donor of one molecule with the DPP core acceptor in another molecule as observed in the crystal structures. Such interactions are found to also increase with the SF coupling energies, as calculated for each derivative. These structural and spectroscopic studies afford a better understanding of the electronic interactions that enhance SF in chromophores having strong intra- and intermolecular CT character.

Effects of sodium salt types on the intermolecular interaction of sodium alginate/antarctic krill protein composite fibers.

Science.gov (United States)

Zhang, Rui; Guo, Jing; Liu, Yuanfa; Chen, Shuang; Zhang, Sen; Yu, Yue

2018-06-01

Sodium alginate (SA) and antarctic krill protein (AKP) were blended to fabricate the SA/AKP composite fibers by the conventional wet spinning method using 5% CaCl 2 as coagulation solution. The sodium salt was added to the SA/AKP solution to adjust the ionization degree and intermolecular interaction of composite system. The main purpose of this study is to investigate the influences of sodium salt types (NaCl, CH 3 COONa, Na 2 SO 4 ) on the intermolecular interaction of SA/AKP composite fibers. The intermolecular interaction, morphology, crystallinity, thermal stability and mechanical properties of SA/AKP composite fibers were analyzed by fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), x-ray diffraction (XRD), thermogravimetric analysis (TGA). The results show that the types of sodium salt have obvious influences on the content of both β-sheet, intermolecular hydrogen bond, breaking strength and surface morphology in SA/AKP composite fibers, but have a negligible effect on the crystallinity and thermal stability. Copyright © 2018 Elsevier Ltd. All rights reserved.

Altering intra- to inter-molecular hydrogen bonding by dimethylsulfoxide: A TDDFT study of charge transfer for coumarin 343

Science.gov (United States)

Liu, Xiaochun; Yin, Hang; Li, Hui; Shi, Ying

2017-04-01

DFT and TDDFT methods were carried out to investigate the influences of intramolecular and intermolecular hydrogen bonding on excited state charge transfer for coumarin 343 (C343). Intramolecular hydrogen bonding is formed between carboxylic acid group and carbonyl group in C343 monomer. However, in dimethylsulfoxide (DMSO) solution, DMSO 'opens up' the intramolecular hydrogen bonding and forms solute-solvent intermolecular hydrogen bonded C343-DMSO complex. Analysis of frontier molecular orbitals reveals that intramolecular charge transfer (ICT) occurs in the first excited state both for C343 monomer and complex. The results of optimized geometric structures indicate that the intramolecular hydrogen bonding interaction is strengthened while the intermolecular hydrogen bonding is weakened in excited state, which is confirmed again by monitoring the shifts of characteristic peaks of infrared spectra. We demonstrated that DMSO solvent can not only break the intramolecular hydrogen bonding to form intermolecular hydrogen bonding with C343 but also alter the mechanism of excited state hydrogen bonding strengthening.

Effect of intermolecular hydrogen bonding, vibrational analysis and molecular structure of a biomolecule: 5-Hydroxymethyluracil

Science.gov (United States)

Çırak, Çağrı; Sert, Yusuf; Ucun, Fatih

2014-06-01

In the present work, the experimental and theoretical vibrational spectra of 5-hydroxymethyluracil were investigated. The FT-IR (4000-400 cm-1) spectrum of the molecule in the solid phase was recorded. The geometric parameters (bond lengths and bond angles), vibrational frequencies, Infrared intensities of the title molecule in the ground state were calculated using density functional B3LYP and M06-2X methods with the 6-311++G(d,p) basis set for the first time. The optimized geometric parameters and theoretical vibrational frequencies were found to be in good agreement with the corresponding experimental data, and with the results found in the literature. The vibrational frequencies were assigned based on the potential energy distribution using the VEDA 4 program. The dimeric form of 5-hydroxymethyluracil molecule was also simulated to evaluate the effect of intermolecular hydrogen bonding on its vibrational frequencies. It was observed that the Nsbnd H stretching modes shifted to lower frequencies, while its in-plane and out-of-plane bending modes shifted to higher frequencies due to the intermolecular Nsbnd H⋯O hydrogen bond. Also, the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies and diagrams were presented.

Photoinduced intermolecular electron transfer and off-resonance Raman characteristics of Rhodamine 101/N,N-diethylaniline

International Nuclear Information System (INIS)

Jiang, Li-lin; Liu, Wei-long; Song, Yun-fei; He, Xing; Wang, Yang; Wang, Chang; Wu, Hong-lin; Yang, Fang; Yang, Yan-qiang

2014-01-01

Highlights: • Mechanism of PIET reaction process for the Rh101 + /DEA system is investigated. • The significant geometrical changes of the charge–transfer complex are explained. • Forward Electron transfer from DEA to Rh101 +∗ occurs with lifetime of 425–560 fs. • Backward electron transfer occurs with a time constant of 46.16–51.40 ps. • Intramolecular vibrational relaxation occurs with lifetime of 2.77–5.39 ps. - Abstract: The ultrafast photoinduced intermolecular electron transfer (PIET) reaction of Rhodamine 101 (Rh101 + ) in N,N-diethylaniline (DEA) was investigated using off-resonance Raman, femtosecond time-resolved multiplex transient grating (TG) and transient absorption (TA) spectroscopies. The Raman spectra indicate that the C=C stretching vibration of the chromophore aromatic ring is more sensitive to ET compared with the C-C stretching mode. The ultrafast photoinduced intermolecular forward ET (FET) from DEA to Rh101 +∗ occurs on a time scale of τ FET = 425–560 fs. The backward ET (BET) occurs in the inverted region with a time constant of τ BET = 46.16–51.40 ps. The intramolecular vibrational relaxation (IVR) process occurs on the excited state potential energy surface with the time constant of τ IVR = 2.77–5.39 ps

Photophysical and computational investigation of the intermolecular interactions of pyrene with phenothiazine and promazine

Energy Technology Data Exchange (ETDEWEB)

Güloğlu, Pınar; Acar, Nursel, E-mail: nursel.acar@ege.edu.tr

2016-10-20

Highlights: • Intermolecular interactions of pyrene with phenothiazine/promazine were investigated. • All investigated systems were optimized at ωB97XD/6-31G(d,p) level in gas phase. • The electronic transitions were determined using frontier orbitals. • Both Py–Pheno and Py–Prom are potential candidates for charge transfer systems. - Abstract: The intermolecular interactions between the pyrene (Py) (as acceptor) and phenothiazine (Pheno), promazine (Prom) (as donors) were investigated using UV/Vis absorption and fluorescence spectroscopy. Fluorescence quenching rate constants for Py–Pheno and Py–Prom systems have been calculated approximately 10{sup 10} M{sup −1} s{sup −1}, indicating diffusion controlled processes. A computational investigation has also been carried out in gas phase at ωB97XD/6-31G(d,p) level. Time-dependent density functional theory (TDDFT) was used to calculate the electronic transitions of molecules at B3LYP/6-311++G(d,p) level. Total electronic energies, complexation energies, free energy differences, excitation wavelengths, and HOMO–LUMO energy gaps are discussed in gas phase. Analyses of first excited singlet states have indicated charge transfers transitions between Py and Pheno, Prom through π–π stacking in gas phase at 433 nm and 466 nm, respectively. Due to its charge transfer character, Py–Pheno and Py–Prom systems seem to be appropriate models to investigate and design photosensitive materials.

Connecting Protein Structure to Intermolecular Interactions: A Computer Modeling Laboratory

Science.gov (United States)

Abualia, Mohammed; Schroeder, Lianne; Garcia, Megan; Daubenmire, Patrick L.; Wink, Donald J.; Clark, Ginevra A.

2016-01-01

An understanding of protein folding relies on a solid foundation of a number of critical chemical concepts, such as molecular structure, intra-/intermolecular interactions, and relating structure to function. Recent reports show that students struggle on all levels to achieve these understandings and use them in meaningful ways. Further, several…

Intermolecular G-quadruplex structure-based fluorescent DNA detection system.

Science.gov (United States)

Zhou, Hui; Wu, Zai-Sheng; Shen, Guo-Li; Yu, Ru-Qin

2013-03-15

Adopting multi-donors to pair with one acceptor could improve the performance of fluorogenic detection probes. However, common dyes (e.g., fluorescein) in close proximity to each other would self-quench the fluorescence, and the fluorescence is difficult to restore. In this contribution, we constructed a novel "multi-donors-to-one acceptor" fluorescent DNA detection system by means of the intermolecular G-quadruplex (IGQ) structure-based fluorescence signal enhancement combined with the hairpin oligonucleotide. The novel IGQ-hairpin system was characterized using the p53 gene as the model target DNA. The proposed system showed an improved assay performance due to the introduction of IGQ-structure into fluorescent signaling probes, which could inhibit the background fluorescence and increase fluorescence restoration amplitude of fluoresceins upon target DNA hybridization. The proof-of-concept scheme is expected to provide new insight into the potential of G-quadruplex structure and promote the application of fluorescent oligonucleotide probes in fundamental research, diagnosis, and treatment of genetic diseases. Copyright © 2012 Elsevier B.V. All rights reserved.

Structural modeling and intermolecular correlation of liquid chlorine dioxide

International Nuclear Information System (INIS)

Ogata, Norio; Hironori, Shimakura; Kawakita, Yukinobu; Ohara, Yukoji; Kohara, Shinji; Takeda, Shinichi

2009-01-01

Chlorine dioxide (ClO 2 ) is water-soluble yellow gas at room temperature. It has long been used as a disinfectant of tap water and various commodities owing to its strong oxidizing activity against various microbial proteins. The oxidizing activity is believed to be due to the presence of unpaired electron in its molecular orbital. Despite wealth of physicochemical studies of gaseous ClO 2 , little is known about liquid ClO 2 , especially about fine molecular structure and intermolecular interactions of liquid ClO 2 . The purpose of this study is to elucidate the fine structure and intermolecular orientations of ClO 2 molecules in its liquid state using a high-energy X-ray diffraction technique. The measurements of liquid ClO 2 were carried out at -50 to 0 degree Celsius using a two-axis diffractometer installed at the BL04B2 beamline in the third-generation synchrotron radiation facility SPring-8 (Hyogo, Japan). The incident X-ray beamline was 113.4 keV in energy and 0.1093 Armstrong in wavelength from a Si(111) monochromator with the third harmonic reflection. Liquid ClO 2 held in a quartz capillary tube was placed in a temperature-controlled vacuum chamber. We obtained a structure factor S(Q) to a range of Q = 0.3-30 Amstrong -1 and a pair distribution function g(r) upon Fourier transform of the S(Q). The total g(r) showed peaks at 1.46, 2.08, 2.48, 3.16 and 4.24 Armstrong. From intramolecular bond lengths of 1.46 Armstrong for Cl-O and 2.48 Armstrong for O-O, O-Cl-O bond angle was estimated to be 116.1 degrees. Peaks at 3.16 and 4.24 Armstrong in the total g(r) strongly indicate presence of specific intermolecular orientations of ClO 2 molecules that are distinct from those observed as a dimer in the solid phase ClO 2 . This view was further supported by molecular simulation using a reverse Monte Carlo method (RMC). (author)

Catalytic Intermolecular Cross-Couplings of Azides and LUMO-Activated Unsaturated Acyl Azoliums

KAUST Repository

Li, Wenjun; Ajitha, Manjaly John; Lang, Ming; Huang, Kuo-Wei; Wang, Jian

2017-01-01

An example for the catalytic synthesis of densely functionalized 1,2,3-triazoles through a LUMO activation mode has been developed. The protocol is enabled by intermolecular cross coupling reactions of azides with in situ-generated alpha

Structural analysis and antimicrobial activity of 2[1H]-pyrimidinethione/selenone derivatives

Science.gov (United States)

Żesławska, Ewa; Korona-Głowniak, Izabela; Szczesio, Małgorzata; Olczak, Andrzej; Żylewska, Alicja; Tejchman, Waldemar; Malm, Anna

2017-08-01

Four new crystal structures of sulfur and selenium analogues of 2[1H]-pyrimidinone derivatives were determined with the use of X-ray diffraction method. The molecular geometry and intermolecular interactions of the investigated molecules were analyzed in order to find the structural features and geometrical parameters, which can be responsible for antimicrobial activities. The influence of chalcogen substituents (sulfur and selenium) on the crystal packing was also studied. The main differences in the molecular structures exist in mutual arrangement of two aromatic rings. The intermolecular interactions in all investigated compounds are similar. Furthermore, the in vitro antibacterial and antifungal activities for these compounds were evaluated. Preliminary investigations have identified two highly potent antibacterial compounds containing selenium atom, which display selectivity towards staphylococci and micrococci. This selectivity was not observed for a control compound used as a drug, namely vancomycin. These compounds possess also good antifungal activity. This is the first report of biological activities of 2[1H]-pyrimidineselenone derivatives.

Photoinduced intermolecular electron transfer and off-resonance Raman characteristics of Rhodamine 101/N,N-diethylaniline

Energy Technology Data Exchange (ETDEWEB)

Jiang, Li-lin [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China); School of Mechanical and Electronic Engineering, Hezhou University, Hezhou 542800 (China); Liu, Wei-long; Song, Yun-fei; He, Xing; Wang, Yang; Wang, Chang; Wu, Hong-lin [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China); Yang, Fang [National Key Laboratory of Science and Technology on Tunable Laser, Department of Optoelectronics Information Science Technology, Harbin Institute of Technology, Harbin 150001 (China); Yang, Yan-qiang, E-mail: yqyang@hit.edu.cn [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China); National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900, Sichuan (China)

2014-01-31

Highlights: • Mechanism of PIET reaction process for the Rh101{sup +}/DEA system is investigated. • The significant geometrical changes of the charge–transfer complex are explained. • Forward Electron transfer from DEA to Rh101{sup +∗} occurs with lifetime of 425–560 fs. • Backward electron transfer occurs with a time constant of 46.16–51.40 ps. • Intramolecular vibrational relaxation occurs with lifetime of 2.77–5.39 ps. - Abstract: The ultrafast photoinduced intermolecular electron transfer (PIET) reaction of Rhodamine 101 (Rh101{sup +}) in N,N-diethylaniline (DEA) was investigated using off-resonance Raman, femtosecond time-resolved multiplex transient grating (TG) and transient absorption (TA) spectroscopies. The Raman spectra indicate that the C=C stretching vibration of the chromophore aromatic ring is more sensitive to ET compared with the C-C stretching mode. The ultrafast photoinduced intermolecular forward ET (FET) from DEA to Rh101{sup +∗} occurs on a time scale of τ{sub FET} = 425–560 fs. The backward ET (BET) occurs in the inverted region with a time constant of τ{sub BET} = 46.16–51.40 ps. The intramolecular vibrational relaxation (IVR) process occurs on the excited state potential energy surface with the time constant of τ{sub IVR} = 2.77–5.39 ps.

The effect of strong intermolecular and chemical interactions on the compatibility of polymers

International Nuclear Information System (INIS)

Askadskii, Andrei A

1999-01-01

The data on compatibility and on the properties of polymer blends are generalised. The emphasis is placed on the formation of strong intermolecular interactions (dipole-dipole interaction and hydrogen bonding) between the components of blends, as well as on the chemical reactions between them. A criterion for the prediction of compatibility of polymers is described in detail. Different cases of compatibility are considered and the dependences of the glass transition temperatures on the composition of blends are analysed. The published data on the effect of strong intermolecular interactions between the blend components on the glass transition temperature are considered. The preparation of interpolymers is described whose macromolecules are composed of incompatible polymers, which leads to the so-called 'forced compatibility.' The bibliography includes 80 references.

Anterior cruciate ligament-derived cells have high chondrogenic potential.

Science.gov (United States)

Furumatsu, Takayuki; Hachioji, Motomi; Saiga, Kenta; Takata, Naoki; Yokoyama, Yusuke; Ozaki, Toshifumi

2010-01-01

Anterior cruciate ligament (ACL)-derived cells have a character different from medial collateral ligament (MCL)-derived cells. However, the critical difference between ACL and MCL is still unclear in their healing potential and cellular response. The objective of this study was to investigate the mesenchymal differentiation property of each ligament-derived cell. Both ligament-derived cells differentiated into adipogenic, osteogenic, and chondrogenic lineages. In chondrogenesis, ACL-derived cells had the higher chondrogenic property than MCL-derived cells. The chondrogenic marker genes, Sox9 and alpha1(II) collagen (Col2a1), were induced faster in ACL-derived pellets than in MCL-derived pellets. Sox9 expression preceded the increase of Col2a1 in both pellet-cultured cells. However, the expression level of Sox9 and a ligament/tendon transcription factor Scleraxis did not parallel the increase of Col2a1 expression along with chondrogenic induction. The present study demonstrates that the balance between Sox9 and Scleraxis have an important role in the chondrogenic differentiation of ligament-derived cells. Copyright 2009 Elsevier Inc. All rights reserved.

Enthalpies of vaporization of some acetylene peroxy derivatives of carboranes-12

International Nuclear Information System (INIS)

Dibrivnyj, V.N.; Pistun, Z.E.; Van-Chin-Syan, Yu.Ya.; Yuvchenko, A.P.; Zvereva, T.D.

1999-01-01

Temperature dependences of saturated vapor pressure and vaporization enthalpies of five acetylene peroxy derivatives of carboranes-12 are determined by the Knudsen effusion method. Enthalpies and melting points of crystals, as well as temperatures of liquid compounds decomposition start are determined by the method of differential scanning calorimetry. Comparison of evaporation enthalpies determined in the study confirms the conclusions on non-additive character of intermolecular interaction in carboranes and their derivatives, which have been made previously [ru

Intermolecular potential energy surface and thermophysical properties of propane.

Science.gov (United States)

Hellmann, Robert

2017-03-21

A six-dimensional potential energy surface (PES) for the interaction of two rigid propane molecules was determined from supermolecular ab initio calculations up to the coupled cluster with single, double, and perturbative triple excitations level of theory for 9452 configurations. An analytical site-site potential function with 14 sites per molecule was fitted to the calculated interaction energies. To validate the analytical PES, the second virial coefficient and the dilute gas shear viscosity and thermal conductivity of propane were computed. The dispersion part of the potential function was slightly adjusted such that quantitative agreement with the most accurate experimental data for the second virial coefficient at room temperature was achieved. The adjusted PES yields values for the three properties that are in very good agreement with the best experimental data at all temperatures.

Effective nucleus-nucleus potentials derived from the generator coordinate method

Energy Technology Data Exchange (ETDEWEB)

Friedrich, H; Canto, L F [Oxford Univ. (UK). Dept. of Theoretical Physics

1977-11-07

The equivalence of the generator coordinate method (GCM) and the resonating group method (RGM) and the formal equivalence of the RGM and the orthogonality condition model (OCM) lead to a relation connecting the effective nucleus-nucleus potentials of the OCM with matrix elements of the GCM. This relation may be used to derive effective nucleus-nucleus potentials directly from GCM matrix elements without explicit reference to the potentials of the RGM. In a first application local and l-independent effective potentials are derived from diagonal GCM matrix elements which represent the energy surfaces of a two-centre shell model. Using these potentials the OCM can reproduce the results of a full RGM calculation very well for the elastic scattering of two ..cap alpha..-particles and fairly well for elastic /sup 16/O-/sup 16/O scattering.

Scalar potential from higher derivative N=1 superspace

International Nuclear Information System (INIS)

Ciupke, David

2016-05-01

The supersymmetric completion of higher-derivative operators often requires introducing corrections to the scalar potential. In this paper we study these corrections systematically in the context of theories with N=1 global and local supersymmetry in D=4 focusing on ungauged chiral multiplets. In globally supersymmetric theories the most general off-shell effective scalar potential can be captured by a dependence of the Kaehler potential on additional chiral superfields. For supergravity we find a much richer structure of possible corrections. In this context we classify the leading order and next-to-leading order superspace derivative operators and determine the component forms of a subclass thereof. Moreover, we present an algorithm that simplifies the computation of the respective on-shell action. As particular applications we study the structure of the supersymmetric vacua for these theories and comment on the form of the corrections to shift-symmetric no-scale models. These results are relevant for the computation of effective actions for string compactifications and, in turn, for moduli stabilization and string inflation.

Placenta-derived exosomes: potential biomarkers of preeclampsia.

Science.gov (United States)

Pillay, Preenan; Moodley, Kogi; Moodley, Jagidesa; Mackraj, Irene

2017-01-01

Preeclampsia remains a leading cause of maternal and fetal mortality, due to ineffective treatment and diagnostic strategies, compounded by the lack of clarity on the etiology of the disorder. Although several clinical and biological markers of preeclampsia have been evaluated, they have proven to be ineffective in providing a definitive diagnosis during the various stages of the disorder. Exosomes have emerged as ideal biomarkers of pathological states, such as cancer, and have more recently gained interest in pregnancy-related complications, due to their role in cellular communication in normal and complicated pregnancies. This occurs as a result of the specific placenta-derived exosomal molecular cargo, which may be involved in normal pregnancy-associated immunological events, such as the maintenance of maternal-fetal tolerance. This review provides perspectives on placenta-derived exosomes as possible biomarkers for the diagnosis/prognosis of preeclampsia. Using keywords, online databases were searched to identify relevant publications to review the potential use of placenta-derived exosomes as biomarkers of preeclampsia.

Instantaneous normal mode analysis for intermolecular and intramolecular vibrations of water from atomic point of view.

Science.gov (United States)

Chen, Yu-Chun; Tang, Ping-Han; Wu, Ten-Ming

2013-11-28

By exploiting the instantaneous normal mode (INM) analysis for models of flexible molecules, we investigate intermolecular and intramolecular vibrations of water from the atomic point of view. With two flexible SPC/E models, our investigations include three aspects about their INM spectra, which are separated into the unstable, intermolecular, bending, and stretching bands. First, the O- and H-atom contributions in the four INM bands are calculated and their stable INM spectra are compared with the power spectra of the atomic velocity autocorrelation functions. The unstable and intermolecular bands of the flexible models are also compared with those of the SPC/E model of rigid molecules. Second, we formulate the inverse participation ratio (IPR) of the INMs, respectively, for the O- and H-atom and molecule. With the IPRs, the numbers of the three species participated in the INMs are estimated so that the localization characters of the INMs in each band are studied. Further, by the ratio of the IPR of the H atom to that of the O atom, we explore the number of involved OH bond per molecule participated in the INMs. Third, by classifying simulated molecules into subensembles according to the geometry of their local environments or their H-bond configurations, we examine the local-structure effects on the bending and stretching INM bands. All of our results are verified to be insensible to the definition of H-bond. Our conclusions about the intermolecular and intramolecular vibrations in water are given.

Highly Stereoselective Intermolecular Haloetherification and Haloesterification of Allyl Amides

Science.gov (United States)

Soltanzadeh, Bardia; Jaganathan, Arvind; Staples, Richard J.

2016-01-01

An organocatalytic and highly regio-, diastereo-, and enantioselective intermolecular haloetherification and haloesterification reaction of allyl amides is reported. A variety of alkene substituents and substitution patterns are compatible with this chemistry. Notably, electronically unbiased alkene substrates exhibit exquisite regio- and diastereoselectivity for the title transformation. We also demonstrate that the same catalytic system can be used in both chlorination and bromination reactions of allyl amides with a variety of nucleophiles with little or no modification. PMID:26110812

On the representation of the electric charge distribution in ethane for calculations of the molecular quadrupole moment and intermolecular electrostatic energy

DEFF Research Database (Denmark)

Hansen, Flemming Yssing; Alldredge, G. P.; Bruch, L. W.

1985-01-01

and gives a repulsive rather than an attractive electrostatic interaction at typical intermolecular distances. In the local multipole model, the atom-site dipoles give the largest contribution to both the molecular quadrupole moment and the intermolecular interaction. The Journal of Chemical Physics...

Evaluation of coupling terms between intra- and intermolecular vibrations in coarse-grained normal-mode analysis: Does a stronger acid make a stiffer hydrogen bond?

Science.gov (United States)

Houjou, Hirohiko

2011-10-01

Using theory of harmonic normal-mode vibration analysis, we developed a procedure for evaluating the anisotropic stiffness of intermolecular forces. Our scheme for coarse-graining of molecular motions is modified so as to account for intramolecular vibrations in addition to relative translational/rotational displacement. We applied this new analytical scheme to four carboxylic acid dimers, for which coupling between intra- and intermolecular vibrations is crucial for determining the apparent stiffness of the intermolecular double hydrogen bond. The apparent stiffness constant was analyzed on the basis of a conjunct spring model, which defines contributions from true intermolecular stiffness and molecular internal stiffness. Consequently, the true intermolecular stiffness was in the range of 43-48 N m-1 for all carboxylic acids studied, regardless of the molecules' acidity. We concluded that the difference in the apparent stiffness can be attributed to differences in the internal stiffness of the respective molecules.

Gibb's energy and intermolecular free length of 'Borassus Flabellifier' (BF) and Adansonia digitata (AnD) aqueous binary mixture

International Nuclear Information System (INIS)

Phadke, Sushil; Shrivastava, Bhakt Darshan; Ujle, S K; Mishra, Ashutosh; Dagaonkar, N

2014-01-01

One of the potential driving forces behind a chemical reaction is favourable a new quantity known as the Gibbs free energy (G) of the system, which reflects the balance between these forces. Ultrasonic velocity and absorption measurements in liquids and liquid mixtures find extensive application to study the nature of intermolecular forces. Ultrasonic velocity measurements have been successfully employed to detect weak and strong molecular interactions present in binary and ternary liquid mixtures. After measuring the density and ultrasonic velocity of aqueous solution of 'Borassus Flabellifier' BF and Adansonia digitata And, we calculated Gibb's energy and intermolecular free length. The velocity of ultrasonic waves was measured, using a multi-frequency ultrasonic interferometer with a high degree of accuracy operating Model M-84 by M/s Mittal Enterprises, New Delhi, at a fixed frequency of 2 MHz. Natural sample 'Borassus Flabellifier' BF fruit pulp and Adansonia digitata AnD powder was collected from Dhar, District of MP, India for this study.

Polyelectrolyte brushes in mixed ionic medium studied via intermolecular forces

Science.gov (United States)

Farina, Robert; Laugel, Nicolas; Pincus, Philip; Tirrell, Matthew

2011-03-01

The vast uses and applications of polyelectrolyte brushes make them an attractive field of research especially with the growing interest in responsive materials. Polymers which respond via changes in temperature, pH, and ionic strength are increasingly being used for applications in drug delivery, chemical gating, etc. When polyelectrolyte brushes are found in either nature (e.g., surfaces of cartilage and mammalian lung interiors) or commercially (e.g., skin care products, shampoo, and surfaces of medical devices) they are always surrounded by mixed ionic medium. This makes the study of these brushes in varying ionic environments extremely relevant for both current and future potential applications. The polyelectrolyte brushes in this work are diblock co-polymers of poly-styrene sulfonate (N=420) and poly-t-butyl styrene (N=20) which tethers to a hydrophobic surface allowing for a purely thermodynamic study of the polyelectrolyte chains. Intermolecular forces between two brushes are measured using the SFA. As multi-valent concentrations are increased, the brushes collapse internally and form strong adhesion between one another after contact (properties not seen in a purely mono-valent environment).

Solvation study of the non-specific lipid transfer protein from wheat by intermolecular NOEs with water and small organic molecules

International Nuclear Information System (INIS)

Liepinsh, Edvards; Sodano, Patrick; Tassin, Severine; Marion, Didier; Vovelle, Francoise; Otting, Gottfried

1999-01-01

Intermolecular nuclear Overhauser effects (NOEs) were measured between the protons of various small solvent or gas molecules and the non-specific lipid transfer protein (ns-LTP) from wheat. Intermolecular NOEs were observed with the hydrophobic pocket in the interior of wheat ns-LTP, which grew in intensity in the order cyclopropane (saturated solution) < methane (140 bar) < ethane (40 bar) < acetonitrile (5% in water) < cyclohexane (saturated solution) < benzene (saturated solution). No intermolecular NOEs were observed with dioxane (5% in water). The intermolecular NOEs were negative for all of the organic molecules tested. Intermolecular NOEs between wheat ns-LTP and water were weak or could not be distinguished from exchange-relayed NOEs. As illustrated by the NOEs with cyclohexane versus dioxane, the hydrophobic pocket in wheat ns-LTP preferably binds non-polar molecules. Yet, polar molecules like acetonitrile can also be accommodated. The pressure dependence of the NOEs between methane and wheat ns-LTP indicated incomplete occupancy, even at 190 bar methane pressure. In general, NOE intensities increased with the size of the ligand molecule and its vapor pressure. NMR of the vapor phase showed excellent resolution between the signals from the gas phase and those from the liquid phase. The vapor concentration of cyclohexane was fivefold higher than that of the dioxane solution, supporting the binding of cyclohexane versus uptake of dioxane

The Potential for Synovium-derived Stem Cells in Cartilage Repair

DEFF Research Database (Denmark)

Kubosch, Eva Johanna; Lang, Gernot Michael; Fürst, David

2018-01-01

for the treatment of large, isolated, full thickness cartilage defects. Several disadvantages such as the need for two surgical procedures or hypertrophic regenerative cartilage, underline the need for alternative cell sources. OBJECTIVE: Mesenchymal stem cells, particularly synovium-derived mesenchymal stem cells......, represent a promising cell source. Synovium-derived mesenchymal stem cells have attracted considerable attention since they display great chondrogenic potential and less hypertrophic differentiation than mesenchymal stem cells derived from bone marrow. The aim of this review was to summarize the current...... knowledge on the chondrogenic potential for synovial stem cells in regard to cartilage repair purposes. RESULTS: A literature search was carried out identifying 260 articles in the databases up to January 2017. Several in vitro and initial animal in vivo studies of cartilage repair using synovia stem cell...

Pharmaceutical cocrystals, salts and multicomponent systems; intermolecular interactions and property based design.

Science.gov (United States)

Berry, David J; Steed, Jonathan W

2017-08-01

As small molecule drugs become harder to develop and less cost effective for patient use, efficient strategies for their property improvement become increasingly important to global health initiatives. Improvements in the physical properties of Active Pharmaceutical Ingredients (APIs), without changes in the covalent chemistry, have long been possible through the application of binary component solids. This was first achieved through the use of pharmaceutical salts, within the last 10-15years with cocrystals and more recently coamorphous systems have also been consciously applied to this problem. In order to rationally discover the best multicomponent phase for drug development, intermolecular interactions need to be considered at all stages of the process. This review highlights the current thinking in this area and the state of the art in: pharmaceutical multicomponent phase design, the intermolecular interactions in these phases, the implications of these interactions on the material properties and the pharmacokinetics in a patient. Copyright © 2017 Elsevier B.V. All rights reserved.

Catalyst-Controlled and Tunable, Chemoselective Silver-Catalyzed Intermolecular Nitrene Transfer: Experimental and Computational Studies.

Science.gov (United States)

Dolan, Nicholas S; Scamp, Ryan J; Yang, Tzuhsiung; Berry, John F; Schomaker, Jennifer M

2016-11-09

The development of new catalysts for selective nitrene transfer is a continuing area of interest. In particular, the ability to control the chemoselectivity of intermolecular reactions in the presence of multiple reactive sites has been a long-standing challenge in the field. In this paper, we demonstrate examples of silver-catalyzed, nondirected, intermolecular nitrene transfer reactions that are both chemoselective and flexible for aziridination or C-H insertion, depending on the choice of ligand. Experimental probes present a puzzling picture of the mechanistic details of the pathways mediated by [( t Bu 3 tpy)AgOTf] 2 and (tpa)AgOTf. Computational studies elucidate these subtleties and provide guidance for the future development of new catalysts exhibiting improved tunability in group transfer reactions.

The origins of the directionality of noncovalent intermolecular interactions.

Science.gov (United States)

Wang, Changwei; Guan, Liangyu; Danovich, David; Shaik, Sason; Mo, Yirong

2016-01-05

The recent σ-hole concept emphasizes the contribution of electrostatic attraction to noncovalent bonds, and implies that the electrostatic force has an angular dependency. Here a set of clusters, which includes hydrogen bonding, halogen bonding, chalcogen bonding, and pnicogen bonding systems, is investigated to probe the magnitude of covalency and its contribution to the directionality in noncovalent bonding. The study is based on the block-localized wavefunction (BLW) method that decomposes the binding energy into the steric and the charge transfer (CT) (hyperconjugation) contributions. One unique feature of the BLW method is its capability to derive optimal geometries with only steric effect taken into account, while excluding the CT interaction. The results reveal that the overall steric energy exhibits angular dependency notably in halogen bonding, chalcogen bonding, and pnicogen bonding systems. Turning on the CT interactions further shortens the intermolecular distances. This bond shortening enhances the Pauli repulsion, which in turn offsets the electrostatic attraction, such that in the final sum, the contribution of the steric effect to bonding is diminished, leaving the CT to dominate the binding energy. In several other systems particularly hydrogen bonding systems, the steric effect nevertheless still plays the major role whereas the CT interaction is minor. However, in all cases, the CT exhibits strong directionality, suggesting that the linearity or near linearity of noncovalent bonds is largely governed by the charge-transfer interaction whose magnitude determines the covalency in noncovalent bonds. © 2015 Wiley Periodicals, Inc.

Mechanism of intermolecular hydroacylation of vinylsilanes catalyzed by a rhodium(I) olefin complex: a DFT study.

Science.gov (United States)

Meng, Qingxi; Shen, Wei; Li, Ming

2012-03-01

Density functional theory (DFT) was used to investigate the Rh(I)-catalyzed intermolecular hydroacylation of vinylsilane with benzaldehyde. All intermediates and transition states were optimized completely at the B3LYP/6-31G(d,p) level (LANL2DZ(f) for Rh). Calculations indicated that Rh(I)-catalyzed intermolecular hydroacylation is exergonic, and the total free energy released is -110 kJ mol(-1). Rh(I)-catalyzed intermolecular hydroacylation mainly involves the active catalyst CA2, rhodium-alkene-benzaldehyde complex M1, rhodium-alkene-hydrogen-acyl complex M2, rhodium-alkyl-acyl complex M3, rhodium-alkyl-carbonyl-phenyl complex M4, rhodium-acyl-phenyl complex M5, and rhodium-ketone complex M6. The reaction pathway CA2 + R2 → M1b → T1b → M2b → T2b1 → M3b1 → T4b → M4b → T5b → M5b → T6b → M6b → P2 is the most favorable among all reaction channels of Rh(I)-catalyzed intermolecular hydroacylation. The reductive elimination reaction is the rate-determining step for this pathway, and the dominant product predicted theoretically is the linear ketone, which is consistent with Brookhart's experiments. Solvation has a significant effect, and it greatly decreases the free energies of all species. The use of the ligand Cp' (Cp' = C(5)Me(4)CF(3)) decreased the free energies in general, and in this case the rate-determining step was again the reductive elimination reaction.

Synthesis, antimalarial activity in vitro, and docking studies of novel neolignan derivatives.

Science.gov (United States)

Pereira, Glaécia A N; Souza, Gisele C; Santos, Lourivaldo S; Barata, Lauro E S; Meneses, Carla C F; Krettli, Antoniana U; Daniel-Ribeiro, Cláudio Tadeu; Alves, Cláudio Nahum

2017-09-01

The absence of effective vaccines against malaria and the difficulties associated with controlling mosquito vectors have left chemotherapy as the primary control measure against malaria. However, the emergence and spread of parasite resistance to conventional antimalarial drugs result in a worrisome scenario making the search for new drugs a priority. In the present study, the activities of nine neolignan derivatives were evaluated as follows: (i) against blood forms of chloroquine-resistant Plasmodium falciparum (clone W2), using the tritiated hypoxanthine incorporation and anti-HRPII assays; (ii) for cytotoxic activity against cultured human hepatoma cells (HepG2); and (iii) for intermolecular interaction with the P. falciparum cysteine protease of falcipain-2 (F2) by molecular docking. The neolignan derivatives 9 and 10 showed activity against the blood form of the chloroquine-resistant P. falciparum clone W2 and were not cytotoxic against cultured human hepatoma cells. A molecular docking study of these two neolignans with FP2 revealed several intermolecular interactions that should guide the design of future analogs. © 2017 John Wiley & Sons A/S.

Studying Intermolecular Forces with a Dual Gas Chromatography and Boiling Point Investigation

Science.gov (United States)

Cunningham, William Patrick; Xia, Ian; Wickline, Kaitlyn; Huitron, Eric Ivan Garcia; Heo, Jun

2018-01-01

A procedure for the study of structural differences and intermolecular attraction between ethanol and 1-butanol based in laboratory work is described. This study provides comparisons of data retrieved from both a determination of boiling point and gas chromatography traces for the mixture. The methodology reported here should provide instructors…

Contrasting intermolecular and intramolecular exciplex formation of a 1,4-dicyano-2-methylnaphthalene-N,N-dimethyl-p-toluidine dyad.

Science.gov (United States)

Imoto, Mitsutaka; Ikeda, Hiroshi; Fujii, Takayuki; Taniguchi, Hisaji; Tamaki, Akihiro; Takeda, Motonori; Mizuno, Kazuhiko

2010-05-07

An intramolecular exciplex is formed upon excitation of the cyclohexane solution of the 1,4-dicyano-2-methylnaphthalene-N,N-dimethyl-p-toluidine dyad, but little if any intramolecular CT complex exists in the ground state of this substance in solution. In contrast, in the crystalline state, the dyad forms an intermolecular mixed-stack CT complex in the ground state and an intermolecular exciplex when it is photoexcited.

The Effect of Intermolecular Halogen Bond on 19F DNP Enhancement in 1, 4-Diiodotetrafluorobenzene/4-OH-TEMPO Supramolecular Assembly

Directory of Open Access Journals (Sweden)

GAO Shan

2017-12-01

Full Text Available Halogen bond, as hydrogen bond, is a non-covalent bond. Dynamic nuclear polarization (DNP technique has been used previously to study hydrogen bonds-mediated intermolecular interactions. However, no study has been carried out so far to study the halogen bond-mediated intermolecular interactions with DNP. In this work, 19F DNP polarization efficiency of the halogen bonds existing in supramolecular assembling by 4-OH-TEMPO and 1,4-diiodotetrafluorobenzene (DITFB was studied on a home-made DNP system. The formation of intermolecular halogen bonds appeared to increase 19F DNP polarization efficiency, suggesting that the spin-spin interactions among electrons were weakened by the halogen bonds, resulting in an increased T2e and a larger saturation factor.

Direct measurements of intermolecular forces by chemical force microscopy

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Vezenov, Dmitri Vitalievich

1999-12-01

Detailed description of intermolecular forces is key to understanding a wide range of phenomena from molecular recognition to materials failure. The unique features of atomic force microscopy (AFM) to make point contact force measurements with ultra high sensitivity and to generate spatial maps of surface topography and forces have been extended to include measurements between well-defined organic molecular groups. Chemical modification of AFM probes with self-assembled monolayers (SAMs) was used to make them sensitive to specific molecular interactions. This novel chemical force microscopy (CFM) technique was used to probe forces between different molecular groups in a range of environments (vacuum, organic liquids and aqueous solutions); measure surface energetics on a nanometer scale; determine pK values of the surface acid and base groups; measure forces to stretch and unbind a short synthetic DNA duplex and map the spatial distribution of specific functional groups and their ionization state. Studies of adhesion forces demonstrated the important contribution of hydrogen bonding to interactions between simple organic functionalities. The chemical identity of the tip and substrate surfaces as well as the medium had a dramatic effect on adhesion between model monolayers. A direct correlation between surface free energy and adhesion forces was established. The adhesion between epoxy polymer and model mixed SAMs varied with the amount of hydrogen bonding component in the monolayers. A consistent interpretation of CFM measurements in polar solvents was provided by contact mechanics models and intermolecular force components theory. Forces between tips and surfaces functionalized with SAMs terminating in acid or base groups depended on their ionization state. A novel method of force titration was introduced for highly local characterization of the pK's of surface functional groups. The pH-dependent changes in friction forces were exploited to map spatially the

Molecular structure, Hirshfeld surface analysis, theoretical investigations and nonlinear optical properties of a novel crystalline chalcone derivative: (E)-1-(5-bromothiophen-2-yl)-3-(p-tolyl)prop-2-en-1-one

Science.gov (United States)

Pramodh, B.; Lokanath, N. K.; Naveen, S.; Naresh, P.; Ganguly, S.; Panda, J.

2018-06-01

In the present work, the crystal structure of a novel chalcone derivative, (E)-1-(5-bromothiophen-2-yl)-3-(p-tolyl) prop-2-en-1-one has been confirmed by X-ray diffraction studies. Hirshfeld surface analysis was carried out to explore the intermolecular interactions. From the Hirshfeld surface analysis it was observed that H⋯H (26.7%) and C⋯H (26.3%) are the major contributors to the intermolecular interactions which stabilizes the crystal structure. The coordinates were optimized using the density functional theory (DFT) calculations using B3LYP hybrid functions with 6-31G(d) basis set. The structural parameters obtained from XRD studies compliment with those calculated using DFT calculations. The HOMO and LUMO energy gap was found to be 4.1778 eV. The molecular electrostatic potential (MEP) was plotted to identify the possible reactions sites of the molecule. Further, non-linear optical (NLO) properties were investigated by calculating hyperpolarizabilities which indicate that the title compound would be a potential candidate for the NLO applications.

Salting Effects as an Illustration of the Relative Strength of Intermolecular Forces

Science.gov (United States)

Person, Eric C.; Golden, Donnie R.; Royce, Brenda R.

2010-01-01

This quick and inexpensive demonstration of the salting of an alcohol out of an aqueous solution illustrates the impact of intermolecular forces on solubility using materials familiar to many students. Ammonium sulfate (fertilizer) is added to an aqueous 35% solution of isopropyl alcohol (rubbing alcohol and water) containing food coloring as a…

A Polarizable and Transferable PHAST CO 2 Potential for Materials Simulation

KAUST Repository

Mullen, Ashley L.; Pham, Tony; Forrest, Katherine A.; Cioce, Christian R.; McLaughlin, Keith; Space, Brian

2013-01-01

Reliable PHAST (Potentials with High Accuracy Speed and Transferability) intermolecular potential energy functions for CO2 have been developed from first principles for use in heterogeneous systems, including one with explicit polarization

Strong Intermolecular Exciton Couplings in Solid-State Circular Dichroism of Aryl Benzyl Sulfoxides

Czech Academy of Sciences Publication Activity Database

Padula, Daniele; Di Pietro, S.; Capozzi, M. A. M.; Cardellicchio, C.; Pescitelli, G.

2014-01-01

Roč. 26, č. 9 (2014), s. 462-470 ISSN 0899-0042 Institutional support: RVO:61388963 Keywords : organic crystals * TDDFT CD calculations * pairwise additive approximation * two-body effects * intermolecular forces in crystal lattices Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.886, year: 2014

1,2,3-Triazole–Diketopyrrolopyrrole Derivatives with TunableSolubility and Intermolecular Interactions

OpenAIRE

Punzi, Angela; Maiorano, Eliana; Nicoletta, Francesca; Blasi, Davide; Ardizzone, Antonio; Ventosa Rull, Nora; Ratera Bastardas, Immaculada; Veciana Miró, Jaume; Farinola, Gianluca M.

2016-01-01

1,2,3-Triazole rings bearing hydrophobic aliphatic or hydrophilic oligoether chains were easily introduced at the two ends of the conjugated skeleton of bisthiophene–diketopyrrolopyrrole (TDPP) derivatives by simple click cycloaddition reactions. The combination of side chains with different structures and polarities on the triazole rings with the side chains on the N-atoms of the lactam groups of the TDPP moiety enabled the solubility and the solid-state spectroscopic properties of the resul...

Deriving muscle fiber diameter from recorded single fiber potential.

Science.gov (United States)

Zalewska, Ewa

2017-12-01

The aim of the study was to estimate muscle fiber diameters through analysis of single muscle fiber potentials (SFPs) recorded in the frontalis muscle of a healthy subject. Our previously developed analytical and graphic method to derive fiber diameter from the analysis of the negative peak duration and the amplitude of SFP, was applied to a sample of ten SFPs recorded in vivo. Muscle fiber diameters derived from the simulation method for the sample of frontalis muscle SFPs are consistent with anatomical data for this muscle. The results confirm the utility of proposed simulation method. Outlying data could be considered as the result of a contribution of other fibers to the potential recorded using an SFEMG electrode. Our graphic tool provides a rapid estimation of muscle fiber diameter. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Intermolecular Interactions in the TMEM16A Dimer Controlling Channel Activity.

Science.gov (United States)

Scudieri, Paolo; Musante, Ilaria; Gianotti, Ambra; Moran, Oscar; Galietta, Luis J V

2016-12-08

TMEM16A and TMEM16B are plasma membrane proteins with Ca 2+ -dependent Cl - channel function. By replacing the carboxy-terminus of TMEM16A with the equivalent region of TMEM16B, we obtained channels with potentiation of channel activity. Progressive shortening of the chimeric region restricted the "activating domain" to a short sequence close to the last transmembrane domain and led to TMEM16A channels with high activity at very low intracellular Ca 2+ concentrations. To elucidate the molecular mechanism underlying this effect, we carried out experiments based on double chimeras, Forster resonance energy transfer, and intermolecular cross-linking. We also modeled TMEM16A structure using the Nectria haematococca TMEM16 protein as template. Our results indicate that the enhanced activity in chimeric channels is due to altered interaction between the carboxy-terminus and the first intracellular loop in the TMEM16A homo-dimer. Mimicking this perturbation with a small molecule could be the basis for a pharmacological stimulation of TMEM16A-dependent Cl - transport.

Brain Potentials for Derivational Morphology: An ERP Study of Deadjectival Nominalizations in Spanish

Science.gov (United States)

Havas, Viktoria; Rodriguez-Fornells, Antoni; Clahsen, Harald

2012-01-01

This study investigates brain potentials to derived word forms in Spanish. Two experiments were performed on derived nominals that differ in terms of their productivity and semantic properties but are otherwise similar, an acceptability judgment task and a reading experiment using event-related brain potentials (ERPs) in which correctly and…

A trans-Complementing Recombination Trap Demonstrates a Low Propensity of Flaviviruses for Intermolecular Recombination▿

Science.gov (United States)

Taucher, Christian; Berger, Angelika; Mandl, Christian W.

2010-01-01

Intermolecular recombination between the genomes of closely related RNA viruses can result in the emergence of novel strains with altered pathogenic potential and antigenicity. Although recombination between flavivirus genomes has never been demonstrated experimentally, the potential risk of generating undesirable recombinants has nevertheless been a matter of concern and controversy with respect to the development of live flavivirus vaccines. As an experimental system for investigating the ability of flavivirus genomes to recombine, we developed a “recombination trap,” which was designed to allow the products of rare recombination events to be selected and amplified. To do this, we established reciprocal packaging systems consisting of pairs of self-replicating subgenomic RNAs (replicons) derived from tick-borne encephalitis virus (TBEV), West Nile virus (WNV), and Japanese encephalitis virus (JEV) that could complement each other in trans and thus be propagated together in cell culture over multiple passages. Any infectious viruses with intact, full-length genomes that were generated by recombination of the two replicons would be selected and enriched by end point dilution passage, as was demonstrated in a spiking experiment in which a small amount of wild-type virus was mixed with the packaged replicons. Using the recombination trap and the JEV system, we detected two aberrant recombination events, both of which yielded unnatural genomes containing duplications. Infectious clones of both of these genomes yielded viruses with impaired growth properties. Despite the fact that the replicon pairs shared approximately 600 nucleotides of identical sequence where a precise homologous crossover event would have yielded a wild-type genome, this was not observed in any of these systems, and the TBEV and WNV systems did not yield any viable recombinant genomes at all. Our results show that intergenomic recombination can occur in the structural region of flaviviruses

Catalytic Intermolecular Cross-Couplings of Azides and LUMO-Activated Unsaturated Acyl Azoliums

KAUST Repository

Li, Wenjun

2017-02-15

An example for the catalytic synthesis of densely functionalized 1,2,3-triazoles through a LUMO activation mode has been developed. The protocol is enabled by intermolecular cross coupling reactions of azides with in situ-generated alpha,beta-unsaturated acyl azoliums. High yields and broad scope as well as the investigation of reaction mechanism are reported.

Therapeutic Potential of Mesenchymal Stem Cell-Derived Exosomes in the Treatment of Eye Diseases.

Science.gov (United States)

Harrell, C Randall; Simovic Markovic, Bojana; Fellabaum, Crissy; Arsenijevic, Aleksandar; Djonov, Valentin; Arsenijevic, Nebojsa; Volarevic, Vladislav

2018-05-18

Mesenchymal stem cells (MSCs) were, due to their immunomodulatory and pro-angiogenic characteristics, extensively explored as new therapeutic agents in cell-based therapy of uveitis, glaucoma, retinal and ocular surface diseases.Since it was recently revealed that exosomes play an important role in biological functions of MSCs, herewith we summarized current knowledge about the morphology, structure, phenotype and functional characteristics of MSC-derived exosomes emphasizing their therapeutic potential in the treatment of eye diseases.MSC-derived exosomes were as efficient as transplanted MSCs in limiting the extent of eye injury and inflammation. Immediately after intravitreal injection, MSC-derived exosomes, due to nano-dimension, diffused rapidly throughout the retina and significantly attenuated retinal damage and inflammation. MSC-derived exosomes successfully delivered trophic and immunomodulatory factors to the inner retina and efficiently promoted survival and neuritogenesis of injured retinal ganglion cells. MSC-derived exosomes efficiently suppressed migration of inflammatory cells, attenuated detrimental Th1 and Th17 cell-driven immune response and ameliorated experimental autoimmune uveitis. MSC-derived exosomes were able to fuse with the lysosomes within corneal cells, enabling delivering of MSC-derived active β-glucuronidase and consequent catabolism of accumulated glycosaminoglycans, indicating their therapeutic potential in the treatment of Mucopolysaccharidosis VII (Sly Syndrome). Importantly, beneficent effects were noticed only in animals that received MSC-derived exosomes and were not seen after therapy with fibroblasts-derived exosomes confirming specific therapeutic potential of MSCs and their products in the treatment of eye diseases.In conclusion, MSC-derived exosomes represent potentially new therapeutic agents in the therapy of degenerative and inflammatory ocular diseases.

Construction of integrable model Kohn-Sham potentials by analysis of the structure of functional derivatives

International Nuclear Information System (INIS)

Gaiduk, Alex P.; Staroverov, Viktor N.

2011-01-01

A directly approximated exchange-correlation potential should, by construction, be a functional derivative of some density functional in order to avoid unphysical results. Using generalized gradient approximations (GGAs) as an example, we show that functional derivatives of explicit density functionals have a very rigid inner structure, the knowledge of which allows one to build the entire functional derivative from a small part. Based on this analysis, we develop a method for direct construction of integrable Kohn-Sham potentials. As an illustration, we transform the model potential of van Leeuwen and Baerends (which is not a functional derivative) into a semilocal exchange potential that has a parent GGA, yields accurate energies, and is free from the artifacts inherent in existing semilocal potential approximations.

Study of interaction in silica glass via model potential approach

Science.gov (United States)

Mann, Sarita; Rani, Pooja

2016-05-01

Silica is one of the most commonly encountered substances in daily life and in electronics industry. Crystalline SiO2 (in several forms: quartz, cristobalite, tridymite) is an important constituent of many minerals and gemstones, both in pure form and mixed with related oxides. Cohesive energy of amorphous SiO2 has been investigated via intermolecular potentials i.e weak Van der Waals interaction and Morse type short-range interaction. We suggest a simple atom-atom based Van der Waals as well as Morse potential to find cohesive energy of glass. It has been found that the study of silica structure using two different model potentials is significantly different. Van der Waals potential is too weak (P.E =0.142eV/molecule) to describe the interaction between silica molecules. Morse potential is a strong potential, earlier given for intramolecular bonding, but if applied for intermolecular bonding, it gives a value of P.E (=-21.92eV/molecule) to appropriately describe the structure of silica.

Human DNA ligase III bridges two DNA ends to promote specific intermolecular DNA end joining

Science.gov (United States)

Kukshal, Vandna; Kim, In-Kwon; Hura, Gregory L.; Tomkinson, Alan E.; Tainer, John A.; Ellenberger, Tom

2015-01-01

Mammalian DNA ligase III (LigIII) functions in both nuclear and mitochondrial DNA metabolism. In the nucleus, LigIII has functional redundancy with DNA ligase I whereas LigIII is the only mitochondrial DNA ligase and is essential for the survival of cells dependent upon oxidative respiration. The unique LigIII zinc finger (ZnF) domain is not required for catalytic activity but senses DNA strand breaks and stimulates intermolecular ligation of two DNAs by an unknown mechanism. Consistent with this activity, LigIII acts in an alternative pathway of DNA double strand break repair that buttresses canonical non-homologous end joining (NHEJ) and is manifest in NHEJ-defective cancer cells, but how LigIII acts in joining intermolecular DNA ends versus nick ligation is unclear. To investigate how LigIII efficiently joins two DNAs, we developed a real-time, fluorescence-based assay of DNA bridging suitable for high-throughput screening. On a nicked duplex DNA substrate, the results reveal binding competition between the ZnF and the oligonucleotide/oligosaccharide-binding domain, one of three domains constituting the LigIII catalytic core. In contrast, these domains collaborate and are essential for formation of a DNA-bridging intermediate by adenylated LigIII that positions a pair of blunt-ended duplex DNAs for efficient and specific intermolecular ligation. PMID:26130724

Modulation of intermolecular interactions in single-molecule magnets

Science.gov (United States)

Heroux, Katie Jeanne

Polynuclear manganese clusters exhibiting interesting magnetic and quantum properties have been an area of intense research since the discovery of the first single-molecule magnet (SMM) in 1993. These molecules, below their blocking temperature, function as single-domain magnetic particles which exhibit classical macroscale magnetic properties as well as quantum mechanical phenomena such as quantum tunnelling of magnetization (QTM) and quantum phase interference. The union of classical and quantum behavior in these nanomaterials makes SMMs ideal candidates for high-density information storage and quantum computing. However, environmental coupling factors (nuclear spins, phonons, neighboring molecules) must be minimized if such applications are ever to be fully realized. The focus of this work is making small structural changes in well-known manganese SMMs in order to drastically enhance the overall magnetic and quantum properties of the system. Well-isolated molecules of high crystalline quality should lead to well-defined energetic and spectral properties as well. An advantage of SMMs over bulk magnetic materials is that they can be chemically altered from a "bottom-up" approach providing a synthetic tool for tuning magnetic properties. This systematic approach is utilized in the work presented herein by incorporating bulky ligands and/or counterions to "isolate" the magnetic core of [Mn4] dicubane SMMs. Reducing intermolecular interactions in the crystal lattice (neighboring molecules, solvate molecules, dipolar interactions) is an important step toward developing viable quantum computing devices. Detailed bulk magnetic studies as well as single crystal magnetization hysteresis and high-frequency EPR studies on these sterically-isolated complexes show enhanced, and sometimes even unexpected, quantum dynamics. The importance of intra- and intermolecular interactions remains a common theme throughout this work, extending to other SMMs of various topology including

Intermolecular hydrogen transfer catalyzed by a flavodehydrogenase, bakers' yeast flavocytochrome b2

International Nuclear Information System (INIS)

Urban, P.; Lederer, F.

1985-01-01

Bakers yeast flavocytochrome b2 is a flavin-dependent L-2-hydroxy acid dehydrogenase which also exhibits transhydrogenase activity. When a reaction takes place between [2- 3 H]lactate and a halogenopyruvate, tritium is found in water and at the halogenolactate C2 position. When the halogenopyruvate undergoes halide ion elimination, tritium is also found at the C3 position of the resulting pyruvate. The amount tau of this intermolecular tritium transfer depends on the initial keto acid-acceptor concentration. At infinite acceptor concentration, extrapolation yields a maximal transfer of 97 +/- 11%. This indicates that the hydroxy acid-derived hydrogen resides transiently on enzyme monoprotic heteroatoms and that exchange with bulk solvent occurs only at the level of free reduced enzyme. Using a minimal kinetic scheme, the rate constant for hydrogen exchange between Ered and solvent is calculated to be on the order of 10(2) M-1 S-1, which leads to an estimated pK approximately equal to 15 for the ionization of the substrate-derived proton while on the enzyme. It is suggested that this hydrogen could be shared between the active site base and Flred N5 anion. It is furthermore shown that some tritium is incorporated into the products when the transhydrogenation is carried out in tritiated water. Finally, with [2-2H]lactate-reduced enzyme, a deuterium isotope effect is observed on the rate of bromopyruvate disappearance. Extrapolation to infinite bromopyruvate concentration yields DV = 4.4. An apparent inverse isotope effect is determined for bromide ion elimination. These results strengthen the idea that oxidoreduction and elimination pathways involve a common carbanionic intermediate

An approach to the intermolecular energy in pure liquids

Directory of Open Access Journals (Sweden)

GAbriel Hernández de la Torre

2010-07-01

Full Text Available Se propone un método para: estimar la energía potencial de repulsión de cualquier molécula central como una función de las densidades ortobáricas en líquidos puros no auto asociados; estimar los parámetros necesarios para calcular la energía de dispersión de London; calcular los números de coordinación promedio, distancias intermoleculares de interacción, diámetros moleculares y de grupos; en moléculas globulares, moléculas planas y parafinas normales.

Localized-overlap approach to calculations of intermolecular interactions

Science.gov (United States)

Rob, Fazle

Symmetry-adapted perturbation theory (SAPT) based on the density functional theory (DFT) description of the monomers [SAPT(DFT)] is one of the most robust tools for computing intermolecular interaction energies. Currently, one can use the SAPT(DFT) method to calculate interaction energies of dimers consisting of about a hundred atoms. To remove the methodological and technical limits and extend the size of the systems that can be calculated with the method, a novel approach has been proposed that redefines the electron densities and polarizabilities in a localized way. In the new method, accurate but computationally expensive quantum-chemical calculations are only applied for the regions where it is necessary and for other regions, where overlap effects of the wave functions are negligible, inexpensive asymptotic techniques are used. Unlike other hybrid methods, this new approach is mathematically rigorous. The main benefit of this method is that with the increasing size of the system the calculation scales linearly and, therefore, this approach will be denoted as local-overlap SAPT(DFT) or LSAPT(DFT). As a byproduct of developing LSAPT(DFT), some important problems concerning distributed molecular response, in particular, the unphysical charge-flow terms were eliminated. Additionally, to illustrate the capabilities of SAPT(DFT), a potential energy function has been developed for an energetic molecular crystal of 1,1-diamino-2,2-dinitroethylene (FOX-7), where an excellent agreement with the experimental data has been found.

Placenta-derived exosomes: potential biomarkers of preeclampsia

Directory of Open Access Journals (Sweden)

Pillay P

2017-10-01

Full Text Available Preenan Pillay,1,2 Kogi Moodley,1 Jagidesa Moodley,3 Irene Mackraj3 1Discipline of Human Physiology, Nelson R Mandela School of Medicine, School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, South Africa; 2Pearson Institute of Higher Education, Midrand, South Africa; 3Women’s Health and HIV Research Group, Nelson R Mandela School of Medicine, School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, South Africa Abstract: Preeclampsia remains a leading cause of maternal and fetal mortality, due to ineffective treatment and diagnostic strategies, compounded by the lack of clarity on the etiology of the disorder. Although several clinical and biological markers of preeclampsia have been evaluated, they have proven to be ineffective in providing a definitive diagnosis during the various stages of the disorder. Exosomes have emerged as ideal biomarkers of pathological states, such as cancer, and have more recently gained interest in pregnancy-related complications, due to their role in cellular communication in normal and complicated pregnancies. This occurs as a result of the specific placenta-derived exosomal molecular cargo, which may be involved in normal pregnancy-associated immunological events, such as the maintenance of maternal–fetal tolerance. This review provides perspectives on placenta-derived exosomes as possible biomarkers for the diagnosis/prognosis of preeclampsia. Using keywords, online databases were searched to identify relevant publications to review the potential use of placenta-derived exosomes as biomarkers of preeclampsia. Keywords: placenta-derived exosomes, preeclampsia, biomarkers

Equations of state of nonspherical fluids by spherical intermolecular potentials

International Nuclear Information System (INIS)

Bastea, S; Ree, F H

1999-01-01

The equilibrium properties of anisotropic molecular fluids can be in principle calculated in a statistical mechanics framework, but the theory is generally too cumbersome for many practical applications. Fortunately, at high densities and temperatures the anisotropy can be averaged-out by means of a density and temperature independent potential (the median) that produces reliable thermodynamics[1,2]. The proposal of Shaw and Johnson[1], which turns out to be the so-called median potential[2], is very successful in predicting the thermodynamics of simple fluids such as N(sub 2) and CO(sub 2) at reasonable high pressures and temperatures[3]. Lebowitz and Percus[2] pointed out some time ago that the success of this approximation could perhaps be understood in terms of a simple theory that treats the asphericity as a perturbation. The median appears to be the best choice for hard nonspherical potential[4], which may explain its success for fluids at high densities, where the hard core contribution is known to be dominant

A chemical approach for site-specific identification of NMR signals from protein side-chain NH3+ groups forming intermolecular ion pairs in protein–nucleic acid complexes

International Nuclear Information System (INIS)

Anderson, Kurtis M.; Nguyen, Dan; Esadze, Alexandre; Zandrashvili, Levani; Gorenstein, David G.; Iwahara, Junji

2015-01-01

Protein–nucleic acid interactions involve intermolecular ion pairs of protein side-chain and DNA or RNA phosphate groups. Using three protein–DNA complexes, we demonstrate that site-specific oxygen-to-sulfur substitution in phosphate groups allows for identification of NMR signals from the protein side-chain NH 3 + groups forming the intermolecular ion pairs. A characteristic change in their 1 H and 15 N resonances upon this modification (i.e., substitution of phosphate to phosphorodithioate) can represent a signature of an intermolecular ion pair. Hydrogen-bond scalar coupling between protein side-chain 15 N and DNA phosphorodithiaote 31 P nuclei provides direct confirmation of the intermolecular ion pair. The same approach is likely applicable to protein–RNA complexes as well

A Polarizable and Transferable PHAST CO 2 Potential for Materials Simulation

KAUST Repository

Mullen, Ashley L.

2013-12-10

Reliable PHAST (Potentials with High Accuracy Speed and Transferability) intermolecular potential energy functions for CO2 have been developed from first principles for use in heterogeneous systems, including one with explicit polarization. The intermolecular potentials have been expressed in a transferable form and parametrized from nearly exact electronic structure calculations. Models with and without explicit many-body polarization effects, known to be important in simulation of interfacial processes, are constructed. The models have been validated on pressure-density isotherms of bulk CO 2 and adsorption in three metal-organic framework (MOF) materials. The present models appear to offer advantages over high quality fluid/liquid state potentials in describing CO2 interactions in interfacial environments where sorbates adopt orientations not commonly explored in bulk fluids. Thus, the nonpolar CO2-PHAST and polarizable CO 2-PHAST* potentials are recommended for materials/interfacial simulations. © 2013 American Chemical Society.

Potential of commercial microwave link network derived rainfall for river runoff simulations

Science.gov (United States)

Smiatek, Gerhard; Keis, Felix; Chwala, Christian; Fersch, Benjamin; Kunstmann, Harald

2017-03-01

Commercial microwave link networks allow for the quantification of path integrated precipitation because the attenuation by hydrometeors correlates with rainfall between transmitter and receiver stations. The networks, operated and maintained by cellphone companies, thereby provide completely new and country wide precipitation measurements. As the density of traditional precipitation station networks worldwide is significantly decreasing, microwave link derived precipitation estimates receive increasing attention not only by hydrologists but also by meteorological and hydrological services. We investigate the potential of microwave derived precipitation estimates for streamflow prediction and water balance analyses, exemplarily shown for an orographically complex region in the German Alps (River Ammer). We investigate the additional value of link derived rainfall estimations combined with station observations compared to station and weather radar derived values. Our river runoff simulation system employs a distributed hydrological model at 100 × 100 m grid resolution. We analyze the potential of microwave link derived precipitation estimates for two episodes of 30 days with typically moderate river flow and an episode of extreme flooding. The simulation results indicate the potential of this novel precipitation monitoring method: a significant improvement in hydrograph reproduction has been achieved in the extreme flooding period that was characterized by a large number of local strong precipitation events. The present rainfall monitoring gauges alone were not able to correctly capture these events.

Effects of Substitutions on the Biodegradation Potential of Benzotriazole Derivatives

Science.gov (United States)

Abu-Dalo, M. A.; O'Brien, I.; Hernandez, M. T.

2018-02-01

Fourteen benzotriazole derivatives were subjected to microcosm tests to study the influence of substitutions on their biodegradation potential. Methylated, nitrated, carboxylated, and propionated bezotriazoles, a heterocyclic triazole, as well as methylated benzimidazoles, were introduced to activated sludge and soil enrichment cultures as the only carbon source. Some of the enrichment cultures were derived from airport soils that had been previously contaminated with aircraft deicing fluids and subsequently enriched with the commercially significant corrosion inhibitor methylbenzotriazole. The 5-methylbenzotriazole and only the carboxylated derivatives were degraded by soil or activated sludge biomass regardless of acclimation conditions. Radiotracer studies of [U-14C] 5-methylbenzotriazole, and [U-14C] 5-carboxybenzotriazole confirmed that relatively high concentrations (25mg L-1) of these derivatives can be completely mineralized in relatively short time frames by microbial consortia regardless of prior exposure. Observations suggested that the growth yield on these compounds is likely low. Biodegradation patterns suggested that carboxylated benzotriazole derivatives are more readily biodegradable than their more popular methylated counterparts.

Recent developments in Cope-type hydroamination reactions of hydroxylamine and hydrazine derivatives.

Science.gov (United States)

Beauchemin, André M

2013-11-07

Cope-type hydroaminations are versatile for the direct amination of alkenes, alkynes and allenes using hydroxylamines and hydrazine derivatives. These reactions occur via a concerted, 5-membered cyclic transition state that is the microscopic reverse of the Cope elimination. This article focuses on recent developments, including intermolecular variants, directed reactions, and asymmetric variants using aldehydes as tethering catalysts, and their applications in target-oriented synthesis.

Toward precise potential energy curves for diatomic molecules, derived from experimental line positions

International Nuclear Information System (INIS)

Helm, H.

1984-01-01

An inverted, first-order perturbation approach is used to derive potential energy curves for diatomic molecules from experimental line positions of molecular bands. The concept adopted here is based on the inverted perturbation analysis (IPA) proposed by Kozman and Hinze, but uses radial eigenfunctions of the trial potential energy curves as basis sets for the perturbation correction. Using molecular linepositions rather than molecular energy levels we circumvent the necessity of defining molecular constants for the molecule prior to the derivation of the potential energy curves. (Author)

The anisotropic potential of molecular hydrogen determined from the scattering of oriented H2 on inert gases

International Nuclear Information System (INIS)

Zandee, A.P.L.M.

1977-01-01

This thesis deals with an experiment aimed at determining the angle dependence of an intermolecular potential between H 2 molecule and a rare gas atom. The small relative difference in total collision cross section for beams of differently oriented H 2 molecules colliding with inert gas atoms in a scattering box is measured (anisotropy A). Through variation of the orientation and by studying its influence on the total collision cross sections, the angle dependence of the intermolecular potential can be arrived at

Quantum electrodynamics with nonrelativistic sources. V. Electromagnetic field correlations and intermolecular interactions between molecules in either ground or excited states

International Nuclear Information System (INIS)

Power, E.A.; Thirunamachandran, T.

1993-01-01

Spatial correlations between electromagnetic fields arising from neutral sources with electric-dipole transition moments are calculated using nonrelativistic quantum electrodynamics in the multipolar formalism. Expressions for electric-electric, magnetic-magnetic, and electric-magnetic correlation functions at two points r and r' are given for a source molecule in either a ground or an excited state. In contrast to the electric-electric and magnetic-magnetic cases there are no electric-magnetic correlations for a ground-state molecule. For an excited molecule the downward transitions contribute additional terms which have modulating factors depending on (r-r')/λ. From these correlation functions electric and magnetic energy densities are found by setting r=r'. These energy densities are then used in a response formalism to calculate intermolecular energy shifts. In the case of two ground-state molecules this leads to the Casimir-Polder potential. However, for a pair of molecules, one or both excited, there are additional terms arising from downward transitions. An important feature of these energies is that they exhibit an R -2 dependence for large intermolecular separations R. This dependence is interpreted in terms of the Poynting vector, which itself can be obtained by setting r=r' in the electric-magnetic correlation function

Theoretical investigations of two adamantane derivatives: A combined X-ray, DFT, QTAIM analysis and molecular docking

Science.gov (United States)

Al-Wahaibi, Lamya H.; Sujay, Subramaniam; Muthu, Gangadharan Ganesh; El-Emam, Ali A.; Venkataramanan, Natarajan S.; Al-Omary, Fatmah A. M.; Ghabbour, Hazem A.; Percino, Judith; Thamotharan, Subbiah

2018-05-01

A detailed structural analysis of two adamantane derivatives namely, ethyl 2-[(Z)-1-(adamantan-1-yl)-3-(phenyl)isothioureido]acetate I and ethyl 2-[(Z)-1-(adamantan-1-yl)-3-(4-fluorophenyl)isothioureido]acetate II is carried out to understand the effect of fluorine substitution. The introduction of fluorine atom alters the crystal packing and is completely different from its parent compound. The fluorine substitution drastically reduced the intermolecular H⋯H contacts and this reduction is compensated by intermolecular F⋯H and F⋯F contacts. The relative contributions of various intermolecular contacts present in these structures were quantified using Hirshfeld surface analysis. Energetically significant molecular pairs were identified from the crystal structures of these compounds using PIXEL method. The structures of I and II are optimized in gas and solvent phases using the B3LYP-D3/6-311++G(d,p) level of theory. The quantum theory of atoms-in-molecules (QTAIM) analysis was carried out to estimate the strengths of various intermolecular contacts present in these molecular dimers. The results suggest that the Hsbnd H bonding take part in the stabilization of crystal structures. The experimental and theoretical UV-Vis results show the variations in HOMO and LUMO energy levels. In silico docking analysis indicates that both compounds I and II may exhibit inhibitory activity against 11-β-hydroxysteroid dehydrogenase 1 (11-β-HSD1).

Assessment of the Larvicidal potentials of Thymol derivatives on ...

African Journals Online (AJOL)

DR. MIKE HORSFALL

*Corresponding author: E-mail. Assessment of the Larvicidal potentials of Thymol derivatives on Anopheles mosquitoes. 1JACK, I R; 1OKOROSAYE-ORUBITE, K; 2BOBMANUEL, R B. 1Department of Chemistry, Rivers State University of Science and Technology, P.M.B. 5080, Port Harcourt, Nigeria. 2Department of Biology ...

Dispersion correction derived from first principles for density functional theory and Hartree-Fock theory.

Science.gov (United States)

Guidez, Emilie B; Gordon, Mark S

2015-03-12

The modeling of dispersion interactions in density functional theory (DFT) is commonly performed using an energy correction that involves empirically fitted parameters for all atom pairs of the system investigated. In this study, the first-principles-derived dispersion energy from the effective fragment potential (EFP) method is implemented for the density functional theory (DFT-D(EFP)) and Hartree-Fock (HF-D(EFP)) energies. Overall, DFT-D(EFP) performs similarly to the semiempirical DFT-D corrections for the test cases investigated in this work. HF-D(EFP) tends to underestimate binding energies and overestimate intermolecular equilibrium distances, relative to coupled cluster theory, most likely due to incomplete accounting for electron correlation. Overall, this first-principles dispersion correction yields results that are in good agreement with coupled-cluster calculations at a low computational cost.

The sesquiterpenoid nootkatone and the absolute configuration of a dibromo derivative.

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Sauer, Anne M; Fronczek, Frank R; Zhu, Betty C R; Crowe, William E; Henderson, Gregg; Laine, Roger A

2003-05-01

Nootkatone, or (4R,4aS,6R)-4,4a,5,6,7,8-hexahydro-4,4a-dimethyl-6-(1-methylethenyl)naphthalen-2(3H)-one, C(15)H(22)O, a sesquiterpene with strong repellent properties against Formosan subterranean termites and other insects, has the valencene skeleton. The dibromo derivative (1S,3R,4S,4aS,6R,8aR)-1,3-dibromo-6-isopropyl-4,4a-dimethyl-1,2,3,4,5,6,7,8-octahydronaphthalen-2-one, C(15)H(24)Br(2)O, has two independent molecules in the asymmetric unit, which differ in the rotation of the isopropyl group with respect to the main skeleton. The C-Br distances are in the range 1.950 (4)-1.960 (4) A. Both independent molecules form zigzag chains, with very short intermolecular carbonyl-carbonyl interactions, having the perpendicular motif and O...C distances of 2.886 (6) and 2.898 (6) A. These chains are flanked by intermolecular Br...Br interactions of distances in the range 4.067 (1)-4.218 (1) A. The absolute configuration of the dibromo derivative was determined, from which that of nootkatone was inferred.

Intermolecular detergent-membrane protein noes for the characterization of the dynamics of membrane protein-detergent complexes.

Science.gov (United States)

Eichmann, Cédric; Orts, Julien; Tzitzilonis, Christos; Vögeli, Beat; Smrt, Sean; Lorieau, Justin; Riek, Roland

2014-12-11

The interaction between membrane proteins and lipids or lipid mimetics such as detergents is key for the three-dimensional structure and dynamics of membrane proteins. In NMR-based structural studies of membrane proteins, qualitative analysis of intermolecular nuclear Overhauser enhancements (NOEs) or paramagnetic resonance enhancement are used in general to identify the transmembrane segments of a membrane protein. Here, we employed a quantitative characterization of intermolecular NOEs between (1)H of the detergent and (1)H(N) of (2)H-perdeuterated, (15)N-labeled α-helical membrane protein-detergent complexes following the exact NOE (eNOE) approach. Structural considerations suggest that these intermolecular NOEs should show a helical-wheel-type behavior along a transmembrane helix or a membrane-attached helix within a membrane protein as experimentally demonstrated for the complete influenza hemagglutinin fusion domain HAfp23. The partial absence of such a NOE pattern along the amino acid sequence as shown for a truncated variant of HAfp23 and for the Escherichia coli inner membrane protein YidH indicates the presence of large tertiary structure fluctuations such as an opening between helices or the presence of large rotational dynamics of the helices. Detergent-protein NOEs thus appear to be a straightforward probe for a qualitative characterization of structural and dynamical properties of membrane proteins embedded in detergent micelles.

A general transformation to canonical form for potentials in pairwise interatomic interactions.

Science.gov (United States)

Walton, Jay R; Rivera-Rivera, Luis A; Lucchese, Robert R; Bevan, John W

2015-06-14

A generalized formulation of explicit force-based transformations is introduced to investigate the concept of a canonical potential in both fundamental chemical and intermolecular bonding. Different classes of representative ground electronic state pairwise interatomic interactions are referenced to a chosen canonical potential illustrating application of such transformations. Specifically, accurately determined potentials of the diatomic molecules H2, H2(+), HF, LiH, argon dimer, and one-dimensional dissociative coordinates in Ar-HBr, OC-HF, and OC-Cl2 are investigated throughout their bound potentials. Advantages of the current formulation for accurately evaluating equilibrium dissociation energies and a fundamentally different unified perspective on nature of intermolecular interactions will be emphasized. In particular, this canonical approach has significance to previous assertions that there is no very fundamental distinction between van der Waals bonding and covalent bonding or for that matter hydrogen and halogen bonds.

Intermolecular RNA Recombination Occurs at Different Frequencies in Alternate Forms of Brome Mosaic Virus RNA Replication Compartments

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Hernan Garcia-Ruiz

2018-03-01

Full Text Available Positive-strand RNA viruses replicate their genomes in membrane-bound replication compartments. Brome mosaic virus (BMV replicates in vesicular invaginations of the endoplasmic reticulum membrane. BMV has served as a productive model system to study processes like virus-host interactions, RNA replication and recombination. Here we present multiple lines of evidence showing that the structure of the viral RNA replication compartments plays a fundamental role and that recruitment of parental RNAs to a common replication compartment is a limiting step in intermolecular RNA recombination. We show that a previously defined requirement for an RNA recruitment element on both parental RNAs is not to function as a preferred crossover site, but in order for individual RNAs to be recruited into the replication compartments. Moreover, modulating the form of the replication compartments from spherular vesicles (spherules to more expansive membrane layers increased intermolecular RNA recombination frequency by 200- to 1000-fold. We propose that intermolecular RNA recombination requires parental RNAs to be recruited into replication compartments as monomers, and that recruitment of multiple RNAs into a contiguous space is much more common for layers than for spherules. These results could explain differences in recombination frequencies between viruses that replicate in association with smaller spherules versus larger double-membrane vesicles and convoluted membranes.

Resonance energy transfer (RET)-Induced intermolecular pairing force: a tunable weak interaction and its application in SWNT separation.

Science.gov (United States)

Pan, Xiaoyong; Chen, Hui; Wang, Wei Zhi; Ng, Siu Choon; Chan-Park, Mary B

2011-07-21

This paper explores evidence of an optically mediated interaction that is active in the separation mechanism of certain selective agents through consideration of the contrasting selective behaviors of two conjugated polymers with distinct optical properties. The involvement of a RET-induced intermolecular pairing force is implied by the different illumination response behaviors. The magnitude of this interaction scales with the external stimulus parameter, the illumination irradiance (I), and thus is tunable. This suggests a facile technique to modify the selectivity of polymers toward specific SWNT species by altering the polymer structure to adjust the corresponding intermolecular interaction. This is the first experimental verification and application of a RET-induced intermolecular pairing force to SWNT separation. With this kind of interaction taken into account, reasonable interpretation of some conflicting data, especially PLE maps, can be easily made. The above conclusion can be applied to other substances as long as they are electrically neutral and there is photon-induced RET between them. The significant magnitude of this interaction makes direct manipulation of molecules/particles possible and is expected to have applications in molecular engineering. © 2011 American Chemical Society

Study of interaction in silica glass via model potential approach

Energy Technology Data Exchange (ETDEWEB)

Mann, Sarita, E-mail: saritaiitr2003@gmail.com [Department of Physics, Panjab University, Chandigarh-160014 (India); Rani, Pooja [D.A.V. College, Sec-10, Chandigarh-160010 (India)

2016-05-06

Silica is one of the most commonly encountered substances in daily life and in electronics industry. Crystalline SiO{sub 2} (in several forms: quartz, cristobalite, tridymite) is an important constituent of many minerals and gemstones, both in pure form and mixed with related oxides. Cohesive energy of amorphous SiO{sub 2} has been investigated via intermolecular potentials i.e weak Van der Waals interaction and Morse type short-range interaction. We suggest a simple atom-atom based Van der Waals as well as Morse potential to find cohesive energy of glass. It has been found that the study of silica structure using two different model potentials is significantly different. Van der Waals potential is too weak (P.E =0.142eV/molecule) to describe the interaction between silica molecules. Morse potential is a strong potential, earlier given for intramolecular bonding, but if applied for intermolecular bonding, it gives a value of P.E (=−21.92eV/molecule) to appropriately describe the structure of silica.

Potential antitumor therapeutic strategies of human amniotic membrane and amniotic fluid-derived stem cells.

Science.gov (United States)

Kang, N-H; Hwang, K-A; Kim, S U; Kim, Y-B; Hyun, S-H; Jeung, E-B; Choi, K-C

2012-08-01

As stem cells are capable of self-renewal and can generate differentiated progenies for organ development, they are considered as potential source for regenerative medicine and tissue replacement after injury or disease. Along with this capacity, stem cells have the therapeutic potential for treating human diseases including cancers. According to the origins, stem cells are broadly classified into two types: embryonic stem cells (ESCs) and adult stem cells. In terms of differentiation potential, ESCs are pluripotent and adult stem cells are multipotent. Amnion, which is a membranous sac that contains the fetus and amniotic fluid and functions in protecting the developing embryo during gestation, is another stem cell source. Amnion-derived stem cells are classified as human amniotic membrane-derived epithelial stem cells, human amniotic membrane-derived mesenchymal stem cells and human amniotic fluid-derived stem cells. They are in an intermediate stage between pluripotent ESCs and lineage-restricted adult stem cells, non-tumorigenic, and contribute to low immunogenicity and anti-inflammation. Furthermore, they are easily available and do not cause any controversial issues in their recovery and applications. Not only are amnion-derived stem cells applicable in regenerative medicine, they have anticancer capacity. In non-engineered stem cells transplantation strategies, amnion-derived stem cells effectively target the tumor and suppressed the tumor growth by expressing cytotoxic cytokines. Additionally, they also have a potential as novel delivery vehicles transferring therapeutic genes to the cancer formation sites in gene-directed enzyme/prodrug combination therapy. Owing to their own advantageous properties, amnion-derived stem cells are emerging as a new candidate in anticancer therapy.

INTERACTIONS: DESIGN, IMPLEMENTATION AND EVALUATION OF A COMPUTATIONAL TOOL FOR TEACHING INTERMOLECULAR FORCES IN HIGHER EDUCATION

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Francisco Geraldo Barbosa

2015-12-01

Full Text Available Intermolecular forces are a useful concept that can explain the attraction between particulate matter as well as numerous phenomena in our lives such as viscosity, solubility, drug interactions, and dyeing of fibers. However, studies show that students have difficulty understanding this important concept, which has led us to develop a free educational software in English and Portuguese. The software can be used interactively by teachers and students, thus facilitating better understanding. Professors and students, both graduate and undergraduate, were questioned about the software quality and its intuitiveness of use, facility of navigation, and pedagogical application using a Likert scale. The results led to the conclusion that the developed computer application can be characterized as an auxiliary tool to assist teachers in their lectures and students in their learning process of intermolecular forces.

Unambiguous Determination of Intermolecular Hydrogen Bond of NMR Structure by Molecular Dynamics Refinement Using All-Atom Force Field and Implicit Solvent Model

International Nuclear Information System (INIS)

Jee, Jun Goo

2010-01-01

It has been shown that AMD refinement is very useful for defining an intermolecular hydrogen bond in NMR structure calculation. The refined structure also provides a clue for explaining the pH dependence in Ub and UIM complexes. As reported by Choi et al., serine-mediated hydrogen bonds are the third most populated hydrogen bonds found in protein-protein intermolecular interactions, after the backbone-backbone and backbone-aspartate ones. The abundance imposes the requirement of an method to determine the interface of protein-protein complexes. The precise geometry is particularly important in the complex structures between Ub and UBDs. Ub recognizes various targets with the same surface, where both hydrophobic and hydrophobic interactions are involved. Hence, the details of the hydrophilic interactions are necessary to find the common binding modes. The structure determination of a biomolecule by NMR depends heavily on the distance restraints derived by the NOE cross peaks that are observed between two protons within 6 A through space. Therefore, the existence of the NOE peaks and their correct assignments to two corresponding protons are essential for an accurate and precise structure determination. Recent developments of NOE assignment and calculation algorithms have enabled the determination of protein 3D structures without any manual interpretation, provided chemical shifts are assigned in most atoms and sufficient NOE peaks exist. Along with these advances, the necessity of determining complicated structures such as complexes is increasing

A chemical approach for site-specific identification of NMR signals from protein side-chain NH{sub 3}{sup +} groups forming intermolecular ion pairs in protein–nucleic acid complexes

Energy Technology Data Exchange (ETDEWEB)

Anderson, Kurtis M. [University of Texas Health Science Center at Houston, Department of NanoMedicine and Biomedical Engineering and Institute of Molecular Medicine (United States); Nguyen, Dan; Esadze, Alexandre; Zandrashvili, Levani [University of Texas Medical Branch, Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics (United States); Gorenstein, David G. [University of Texas Health Science Center at Houston, Department of NanoMedicine and Biomedical Engineering and Institute of Molecular Medicine (United States); Iwahara, Junji, E-mail: juiwahar@utmb.edu, E-mail: j.iwahara@utmb.edu [University of Texas Medical Branch, Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics (United States)

2015-05-15

Protein–nucleic acid interactions involve intermolecular ion pairs of protein side-chain and DNA or RNA phosphate groups. Using three protein–DNA complexes, we demonstrate that site-specific oxygen-to-sulfur substitution in phosphate groups allows for identification of NMR signals from the protein side-chain NH{sub 3}{sup +} groups forming the intermolecular ion pairs. A characteristic change in their {sup 1}H and {sup 15}N resonances upon this modification (i.e., substitution of phosphate to phosphorodithioate) can represent a signature of an intermolecular ion pair. Hydrogen-bond scalar coupling between protein side-chain {sup 15}N and DNA phosphorodithiaote {sup 31}P nuclei provides direct confirmation of the intermolecular ion pair. The same approach is likely applicable to protein–RNA complexes as well.

Synthesis of naturally-derived macromolecules through simplified electrochemically mediated ATRP

Directory of Open Access Journals (Sweden)

Paweł Chmielarz

2017-11-01

Full Text Available The flavonoid-based macroinitiator was received for the first time by the transesterification reaction of quercetin with 2-bromoisobutyryl bromide. In accordance with the “grafting from” strategy, a naturally-occurring star-like polymer with a polar 3,3',4',5,6-pentahydroxyflavone core and hydrophobic poly(tert-butyl acrylate (PtBA side arms was synthesized via a simplified electrochemically mediated ATRP (seATRP, utilizing only 78 ppm by weight (wt of a catalytic CuII complex. To demonstrate the possibility of temporal control, seATRP was carried out utilizing a multiple-step potential electrolysis. The rate of the polymerizations was well-controlled by applying optimal potential values during preparative electrolysis to prevent the possibility of intermolecular coupling of the growing polymer arms. This appears to be the first report using on-demand seATRP for the synthesis of QC-(PtBA-Br5 pseudo-star polymers. The naturally-derived macromolecules showed narrow MWDs (Đ = 1.08–1.11. 1H NMR spectral results confirm the formation of quercetin-based polymers. These new flavonoid-based polymer materials may find applications as antifouling coatings and drug delivery systems.

Analysis of intermolecular RNA-RNA recombination by rubella virus

International Nuclear Information System (INIS)

Adams, Sandra D.; Tzeng, W.-P.; Chen, M.-H.; Frey, Teryl K.

2003-01-01

To investigate whether rubella virus (RUB) undergoes intermolecular RNA-RNA recombination, cells were cotransfected with pairs of in vitro transcripts from genomic cDNA plasmid vectors engineered to contain nonoverlapping deletions: the replicative transcript maintained the 5'-proximal nonstructural (NS) ORF (which contained the replicase, making it RNA replication competent), had a deletion in the 3'-proximal structural protein (SP) ORF, and maintained the 3' end of the genome, including the putative 3' cis-acting elements (CSE), while the nonreplicative transcript consisted of the 3' half of the genome including the SP-ORF and 3' CSE. Cotransfection yielded plaque-forming virus that synthesized the standard genomic and subgenomic RNAs and thus was generated by RNA-RNA recombination. Using transcripts tagged with a 3'-terminal deletion, it was found that recombinants contained the 3' end derived from the replicative strand, indicating a cis-preference for initiation of negative-strand synthesis. In cotransfections in which the replicative transcript lacked the 3' CSE, recombination occurred, albeit at lower efficiency, indicating that initiation in trans from the NS-ORF can occur. The 3' CSE was sufficient as a nonreplicative transcript, showing that it can serve as a promoter for negative-strand RNA synthesis. While deletion mutagenesis showed that the presence of the junction untranslated region (J-UTR) between the ORFs appeared to be necessary on both transcripts for recombination in this region of the genome, analysis with transcripts tagged with restriction sites showed that the J-UTR was not a hot spot for recombination compared to neighboring regions in both ORFs. Sequence analysis of recombinants revealed that both precise (homologous) and imprecise recombination (aberrant, homologous resulting in duplications) occurred; however, imprecise recombination only involved the J-UTR or the 3' end of the NS-ORF and the J-UTR (maintaining the NS-ORF), indicating

The study of intermolecular interactions in NLO crystal melaminium chloride hemihydrate using DFT simulation and Hirshfeld surface analysis

Science.gov (United States)

Sangeetha, K.; Kumar, V. R. Suresh; Marchewka, M. K.; Binoy, J.

2018-05-01

Since, the intermolecular interactions play a crucial role in the formation of crystalline network, its analysis throws light on structure dependent crystalline properties. In the present study, DFT based vibrational spectral investigation has been performed in the stretching region (3500 cm-1 - 2800 cm-1) of IR and Raman spectra of melaminium chloride hemihydrates. The intermolecular interaction has been investigated by analyzing the half width of the OH and NH stretching profile of the deconvoluted spectra. Correlation of vibrational spectra with Hirshfeld surface analysis and finger print plot has been contemplated and molecular docking studies has been performed on melaminium chloride hemihydrate to assess its role in the drug transport mechanism and toxicity to human body.

Synthesis, characterization, crystal structure and quantum chemical investigations of three novel coumarin-benzenesulfonohydrazide derivatives

Science.gov (United States)

Chethan Prathap, K. N.; Lokanath, N. K.

2018-04-01

Coumarin derivatives are an important class of heterocyclic compounds due to their physical and biological properties. Coumarin derivatives have been identified with many significant electro-optical properties and biological activities. Three novel coumarin derivatives containing benzene sulfonohydrazide group were synthesized by condensation reaction. The synthesized compounds were characterized by various spectroscopic techniques (Mass, 1H/13C NMR and FTIR). Thermal and optical properties were investigated by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and UV-Vis spectroscopic studies. Finally their structures were confirmed by single crystal X-ray diffraction (XRD) studies. The three compounds exhibit diverse intermolecular interactions, as observed by the crystal packing and Hirshfeld surface analysis. Further, their structures were optimized by density functional theory (DFT) calculations using B3LYP hybrid functionals with 6-311G+(d,p) level basis set. The Mulliken charge, molecular electrostatic potential (MEP), frontier molecular orbitals (HOMO-LUMO) were investigated. The experimentally determined parameters were compared with those calculated theoretically and they complement each other with a very good correlation. The transitions among the molecular orbitals were investigated using time-dependent density functional theory (TD-DFT) and the electronic absorption spectra obtained showed very good agreement with the experimentally measured UV-Vis spectra. Furthermore, non-linear optical (NLO) properties were investigated by calculating polarizabilities and hyperpolarizabilities. All three compounds exhibit significantly high hyperpolarizabilities compared to the reference material urea, which makes them potential candidates for NLO applications.

Effective intermolecular potential and critical point for C60 molecule

Science.gov (United States)

Ramos, J. Eloy

2017-07-01

The approximate nonconformal (ANC) theory is applied to the C60 molecule. A new binary potential function is developed for C60, which has three parameters only and is obtained by averaging the site-site carbon interactions on the surface of two C60 molecules. It is shown that the C60 molecule follows, to a good approximation, the corresponding states principle with n-C8H18, n-C4F10 and n-C5F12. The critical point of C60 is estimated in two ways: first by applying the corresponding states principle under the framework of the ANC theory, and then by using previous computer simulations. The critical parameters obtained by applying the corresponding states principle, although very different from those reported in the literature, are consistent with the previous results of the ANC theory. It is shown that the Girifalco potential does not correspond to an average of the site-site carbon-carbon interaction.

Photochemical reduction of water-soluble C60 derivatives (EPR study)

International Nuclear Information System (INIS)

Brezova, V.; Stasko, A.; Dvoranova, D.; Asmus, K.D.; Guldi, D.M.

1999-01-01

The photochemical reduction of three bis-functionalized C 60 derivatives resulted in the formation of a single radical product, characterized by relatively narrow EPR line (g M = 2.0007, pp < 0.02 mT). In the irradiated aqueous solutions containing L-ascorbic acid, in the addition to the EPR line related to bis-adduct mono-anion, also 6-line EPR spectrum of ascorbyl radical was observed. Consequently, the photoinduced formation of ascorbyl radical was attributed to the intermolecular quenching of fullerenes excited states. (authors)

Coiodação de alquenos com nucleófilos oxigenados: reações intermoleculares

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Sanseverino Antonio Manzolillo

2001-01-01

Full Text Available A review on the electrophilic addition of iodine to alkenes in the presence of oxygen containing nucleophiles (cohalogenation reaction is presented. The intermolecular reactions are discussed with emphasis in methods of reaction and synthetic applications of the resulting vicinal iodo-functionalized products (iodohydrins, beta-iodoethers and beta-iodocarboxylates.

Intermolecular potential energy surface and thermophysical properties of ethylene oxide.

Science.gov (United States)

Crusius, Johann-Philipp; Hellmann, Robert; Hassel, Egon; Bich, Eckard

2014-10-28

A six-dimensional potential energy hypersurface (PES) for two interacting rigid ethylene oxide (C2H4O) molecules was determined from high-level quantum-chemical ab initio calculations. The counterpoise-corrected supermolecular approach at the MP2 and CCSD(T) levels of theory was utilized to determine interaction energies for 10178 configurations of two molecules. An analytical site-site potential function with 19 sites per ethylene oxide molecule was fitted to the interaction energies and fine tuned to agree with data for the second acoustic virial coefficient from accurate speed of sound measurements. The PES was validated by computing the second virial coefficient, shear viscosity, and thermal conductivity. The values of these properties are substantiated by the best experimental data as they tend to fall within the uncertainty intervals and also obey the experimental temperature functions, except for viscosity, where experimental data are insufficient. Due to the lack of reliable data, especially for the transport properties, our calculated values are currently the most accurate estimates for these properties of ethylene oxide.

MSCs-derived exosomes: cell-secreted nanovesicles with regenerative potential

Directory of Open Access Journals (Sweden)

Ana Marote

2016-08-01

Full Text Available Exosomes are membrane-enclosed nanovesicles (30-150 nm that shuttle active cargoes between different cells. These tiny extracellular vesicles have been recently isolated from mesenchymal stem cells (MSCs conditioned medium, a population of multipotent cells identified in several adult tissues. MSCs paracrine activity has been already shown to be the key mediator of their elicited regenerative effects. On the other hand, the individual contribution of MSCs-derived exosomes for these effects is only now being unraveled. The administration of MSCs-derived exosomes has been demonstrated to restore tissue function in multiple diseases/injury models and to induce beneficial in vitro effects, mainly mediated by exosomal-enclosed miRNAs. Additionally, the source and the culture conditions of MSCs have been shown to influence the regenerative responses induced by exosomes. Therefore, these studies reveal that MSCs-derived exosomes hold a great potential for cell-free therapies that are safer and easier to manipulate than cell-based products. Nevertheless, this is an emerging research field and hence, further studies are required to understand the full dimension of this complex intercellular communication system and how it can be optimized to take full advantage of its therapeutic effects. In this mini-review, we summarize the most significant new advances in the regenerative properties of MSCs-derived exosomes and discuss the molecular mechanisms underlying these effects.

Vegetable oil-derived epoxy monomers and polymer blends: A comparative study with review

Directory of Open Access Journals (Sweden)

T. P. Schuman

2013-03-01

Full Text Available Glycidyl esters of epoxidized fatty acids derived from soybean oil (EGS and linseed oil (EGL have been synthesized to have higher oxirane content, more reactivity and lower viscosity than epoxidized soybean oil (ESO or epoxidized linseed oil (ELO. The EGS and ESO, for comparison, were used neat and in blends with diglycidyl ether of bisphenol A (DGEBA. Thermosetting resins were fabricated with the epoxy monomers and either BF3 catalyst or anhydride. The curing behaviors, glass transition temperatures, crosslink densities and mechanical properties were tested. The results indicated that polymer glass transition temperatures were mostly a function of oxirane content with additional influence of glycidyl versus internal oxirane reactivity, pendant chain content, and chemical structure and presence of saturated components. EGS provided better compatibility with DGEBA, improved intermolecular crosslinking and glass transition temperature, and yielded mechanically stronger polymerized materials than materials obtained using ESO. Other benefits of the EGS resin blend systems were significantly reduced viscosities compared to either DGEBA or ESO-blended DGEBA counterparts. Therefore, EGS that is derived from renewable sources has improved potential for fabrication of structural and structurally complex epoxy composites, e.g., by vacuum-assisted resin transfer molding.

Structure formation in bis(terpyridine) derivative adlayers: molecule-substrate versus molecule-molecule interactions.

Science.gov (United States)

Hoster, Harry E; Roos, Matthias; Breitruck, Achim; Meier, Christoph; Tonigold, Katrin; Waldmann, Thomas; Ziener, Ulrich; Landfester, Katharina; Behm, R Jürgen

2007-11-06

The influence of the substrate and the deposition conditions-vapor deposition versus deposition from solution-on the structures formed upon self-assembly of deposited bis(terpyridine) derivative (2,4'-BTP) monolayers on different hexagonal substrates, including highly oriented pyrolytic graphite (HOPG), Au(111), and (111)-oriented Ag thin films, was investigated by high-resolution scanning tunneling microscopy and by model calculations of the intermolecular energies and the lateral corrugation of the substrate-adsorbate interaction. Similar quasi-quadratic network structures with almost the same lattice constants obtained on all substrates are essentially identical to the optimum configuration expected from an optimization of the adlayer structure with C-H...N-type bridging bonds as a structure-determining factor, which underlines a key role of the intermolecular interactions in adlayer order. Slight distortions from the optimum values to form commensurate adlayer structures on the metal substrates and the preferential orientation of the adlayer with respect to the substrate are attributed to the substrate-adsorbate interactions, specifically, the lateral corrugation in the substrate-adsorbate interaction upon lateral displacement and rotation of the adsorbed BTP molecules. The fact that similar adlayer structures are obtained on HOPG under ultrahigh vacuum conditions (solid|gas interface) and on HOPG in trichlorobenzene (solid|liquid interface) indicates that the intermolecular interactions are not severely affected by the solvent.

Antifouling potentials of eight deep-sea-derived fungi from the South China Sea.

Science.gov (United States)

Zhang, Xiao-Yong; Xu, Xin-Ya; Peng, Jiang; Ma, Chun-Feng; Nong, Xu-Hua; Bao, Jie; Zhang, Guang-Zhao; Qi, Shu-Hua

2014-04-01

Marine-derived microbial secondary metabolites are promising potential sources of nontoxic antifouling agents. The search for environmentally friendly and low-toxic antifouling components guided us to investigate the antifouling potentials of eight novel fungal isolates from deep-sea sediments of the South China Sea. Sixteen crude ethyl acetate extracts of the eight fungal isolates showed distinct antibacterial activity against three marine bacteria (Loktanella hongkongensis UST950701-009, Micrococcus luteus UST950701-006 and Pseudoalteromonas piscida UST010620-005), or significant antilarval activity against larval settlement of bryozoan Bugula neritina. Furthermore, the extract of Aspergillus westerdijkiae DFFSCS013 displayed strong antifouling activity in a field trial lasting 4 months. By further bioassay-guided isolation, five antifouling alkaloids including brevianamide F, circumdatin F and L, notoamide C, and 5-chlorosclerotiamide were isolated from the extract of A. westerdijkiae DFFSCS013. This is the first report about the antifouling potentials of metabolites of the deep-sea-derived fungi from the South China Sea, and the first stage towards the development of non- or low-toxic antifouling agents from deep-sea-derived fungi.

Binding Cellulose and Chitosan via Intermolecular Inclusion Interaction: Synthesis and Characterisation of Gel

Directory of Open Access Journals (Sweden)

Jiufang Duan

2015-01-01

Full Text Available A novel cellulose-chitosan gel was successfully prepared in three steps: (1 ferrocene- (Fc- cellulose with degrees of substitution (DS of 0.5 wt% was synthesised by ferrocenecarboxylic acid and cellulose within dimethylacetamide/lithium chloride (DMAc/LiCl; (2 the β-cyclodextrin (β-CD groups were introduced onto the chitosan chains by reacting chitosan with epichlorohydrin in dimethyl sulphoxide and a DS of 0.35 wt%; (3 thus, the cellulose-chitosan gel was obtained via an intermolecular inclusion interaction of Fc-cellulose and β-CD-chitosan in DMA/LiCl, that is, by an intermolecular inclusion interaction, between the Fc groups of cellulose and the β-CD groups on the chitosan backbone at room temperature. The successful synthesis of Fc-cellulose and β-CD-chitosan was characterised by 13C-NMR spectroscopy. The gel based on β-CD-chitosan and Fc-cellulose was formed under mild conditions which can engender autonomous healing between cut surfaces after 24 hours: the gel cannot self-heal while the cut surfaces were coated with a solution of a competitive guest (adamantane acid. The cellulose-chitosan complex made by this method underwent self-healing. Therefore, this study provided a novel method of expanding the application of chitosan by binding it with another polymer.

Intermolecular rhodium-catalyzed [2 + 2 + 2] carbocyclization reactions of 1,6-enynes with symmetrical and unsymmetrical alkynes†

Science.gov (United States)

Andrew Evans, P.; Sawyer, James R.; Lai, Kwong Wah; Huffman, John C.

2006-01-01

The crossed intermolecular rhodium-catalyzed [2 + 2 + 2] carbocyclization of carbon and heteroatom tethered 1,6-enynes can be accomplished with symmetrical and unsymmetrical alkynes, to afford the corresponding bicyclohexadienes in an efficient and highly selective manner. PMID:16075089

Synthesis of novel (-)-epicatechin derivatives as potential endothelial GPER agonists: Evaluation of biological effects.

Science.gov (United States)

Sarmiento, Viviana; Ramirez-Sanchez, Israel; Moreno-Ulloa, Aldo; Romero-Perez, Diego; Chávez, Daniel; Ortiz, Miguel; Najera, Nayelli; Correa-Basurto, Jose; Villarreal, Francisco; Ceballos, Guillermo

2018-02-15

To potentially identify proteins that interact (i.e. bind) and may contribute to mediate (-)-epicatechin (Epi) responses in endothelial cells we implemented the following strategy: 1) synthesis of novel Epi derivatives amenable to affinity column use, 2) in silico molecular docking studies of the novel derivatives on G protein-coupled estrogen receptor (GPER), 3) biological assessment of the derivatives on NO production, 4) implementation of an immobilized Epi derivative affinity column and, 5) affinity column based isolation of Epi interacting proteins from endothelial cell protein extracts. For these purposes, the Epi phenol and C3 hydroxyl groups were chemically modified with propargyl or mesyl groups. Docking studies of the novel Epi derivatives on GPER conformers at 14 ns and 70 ns demostrated favorable thermodynamic interactions reaching the binding site. Cultures of bovine coronary artery endothelial cells (BCAEC) treated with Epi derivatives stimulated NO production via Ser1179 phosphorylation of eNOS, effects that were attenuated by the use of the GPER blocker, G15. Epi derivative affinity columns yielded multiple proteins from BCAEC. Proteins were electrophoretically separated and inmmunoblotting analysis revealed GPER as an Epi derivative binding protein. Altogether, these results validate the proposed strategy to potentially isolate and identify novel Epi receptors that may account for its biological activity. Copyright © 2018 Elsevier Ltd. All rights reserved.

Intermolecular interaction studies of glyphosate with water

Science.gov (United States)

Manon, Priti; Juglan, K. C.; Kaur, Kirandeep; Sethi, Nidhi; Kaur, J. P.

2017-07-01

The density (ρ), viscosity (η) and ultrasonic velocity (U) of glyphosate with water have been measured on different ultrasonic frequency ranges from 1MHz, 2MHz, 3MHz & 5MHz by varying concentrations (0.05%, 0.10%, 0.15%, 0.20%, 0.25%, 0.30%, 0.35%, & 0.40%) at 30°C. The specific gravity bottle, Ostwald's viscometer and quartz crystal interferometer were used to determine density (ρ), viscosity (η) and ultrasonic velocity (U). These three factors contribute in evaluating the other parameters as acoustic impedance (Z), adiabatic compressibility (β), relaxation time (τ), intermolecular free length (Lf), free volume (Vf), ultrasonic attenuation (α/f2), Rao's constant (R), Wada's constant (W) and relative strength (R). Solute-solvent interaction is confirmed by ultrasonic velocity and viscosity values, which increases with increase in concentration indicates stronger association between solute and solvent molecules. With rise in ultrasonic frequency the interaction between the solute and solvent particles decreases. The linear variations in Rao's constant and Wada's constant suggest the absence of complex formation.

Intermolecular Interactions in Crystalline Theobromine as Reflected in Electron Deformation Density and (13)C NMR Chemical Shift Tensors.

Science.gov (United States)

Bouzková, Kateřina; Babinský, Martin; Novosadová, Lucie; Marek, Radek

2013-06-11

An understanding of the role of intermolecular interactions in crystal formation is essential to control the generation of diverse crystalline forms which is an important concern for pharmaceutical industry. Very recently, we reported a new approach to interpret the relationships between intermolecular hydrogen bonding, redistribution of electron density in the system, and NMR chemical shifts (Babinský et al. J. Phys. Chem. A, 2013, 117, 497). Here, we employ this approach to characterize a full set of crystal interactions in a sample of anhydrous theobromine as reflected in (13)C NMR chemical shift tensors (CSTs). The important intermolecular contacts are identified by comparing the DFT-calculated NMR CSTs for an isolated theobromine molecule and for clusters composed of several molecules as selected from the available X-ray diffraction data. Furthermore, electron deformation density (EDD) and shielding deformation density (SDD) in the proximity of the nuclei involved in the proposed interactions are calculated and visualized. In addition to the recently reported observations for hydrogen bonding, we focus here particularly on the stacking interactions. Although the principal relations between the EDD and CST for hydrogen bonding (HB) and stacking interactions are similar, the real-space consequences are rather different. Whereas the C-H···X hydrogen bonding influences predominantly and significantly the in-plane principal component of the (13)C CST perpendicular to the HB path and the C═O···H hydrogen bonding modulates both in-plane components of the carbonyl (13)C CST, the stacking modulates the out-of-plane electron density resulting in weak deshielding (2-8 ppm) of both in-plane principal components of the CST and weak shielding (∼ 5 ppm) of the out-of-plane component. The hydrogen-bonding and stacking interactions may add to or subtract from one another to produce total values observed experimentally. On the example of theobromine, we demonstrate

On the trends of Fukui potential and hardness potential derivatives in isolated atoms vs. atoms in molecules.

Science.gov (United States)

Bhattacharjee, Rituparna; Roy, Ram Kinkar

2014-10-28

In the present study, trends of electronic contribution to molecular electrostatic potential [Vel(r¯)(r=0)], Fukui potential [v(+)f|(r=0) and v(-)f|(r=0)] and hardness potential derivatives [Δ(+)h(k) and Δ(-)h(k)] for isolated atoms as well as atoms in molecules are investigated. The generated numerical values of these three reactivity descriptors in these two electronically different situations are critically analyzed through the relevant formalism. Values of Vel(r¯) (when r → 0, i.e., on the nucleus) are higher for atoms in molecules than that of isolated atoms. In contrast, higher values of v(+)|(r=0) and v(-)|(r=0) are observed for isolated atoms compared to the values for atoms in a molecule. However, no such regular trend is observed for the Δ(+)h(k) and Δ(-)h(k) values, which is attributed to the uncertainty in the Fukui function values of atoms in molecules. The sum of Fukui potential and the sum of hardness potential derivatives in molecules are also critically analyzed, which shows the efficacy of orbital relaxation effects in quantifying the values of these parameters. The chemical consequence of the observed trends of these descriptors in interpreting electron delocalization, electronic relaxation and non-negativity of atomic Fukui function indices is also touched upon. Several commonly used molecules containing carbon as well as heteroatoms are chosen to make the investigation more insightful.

Novel Thiazole Derivatives of Medicinal Potential: Synthesis and Modeling

Directory of Open Access Journals (Sweden)

Nour E. A. Abdel-Sattar

2017-01-01

Full Text Available This paper reports on the synthesis of new thiazole derivatives that could be profitably exploited in medical treatment of tumors. Molecular electronic structures have been modeled within density function theory (DFT framework. Reactivity indices obtained from the frontier orbital energies as well as electrostatic potential energy maps are discussed and correlated with the molecular structure. X-ray crystallographic data of one of the new compounds is measured and used to support and verify the theoretical results.

The potential of induced pluripotent stem cell derived hepatocytes.

Science.gov (United States)

Hannoun, Zara; Steichen, Clara; Dianat, Noushin; Weber, Anne; Dubart-Kupperschmitt, Anne

2016-07-01

Orthotopic liver transplantation remains the only curative treatment for liver disease. However, the number of patients who die while on the waiting list (15%) has increased in recent years as a result of severe organ shortages; furthermore the incidence of liver disease is increasing worldwide. Clinical trials involving hepatocyte transplantation have provided encouraging results. However, transplanted cell function appears to often decline after several months, necessitating liver transplantation. The precise aetiology of the loss of cell function is not clear, but poor engraftment and immune-mediated loss appear to be important factors. Also, primary human hepatocytes (PHH) are not readily available, de-differentiate, and die rapidly in culture. Hepatocytes are available from other sources, such as tumour-derived human hepatocyte cell lines and immortalised human hepatocyte cell lines or porcine hepatocytes. However, all these cells suffer from various limitations such as reduced or differences in functions or risk of zoonotic infections. Due to their significant potential, one possible inexhaustible source of hepatocytes is through the directed differentiation of human induced pluripotent stem cells (hiPSCs). This review will discuss the potential applications and existing limitations of hiPSC-derived hepatocytes in regenerative medicine, drug screening, in vitro disease modelling and bioartificial livers. Copyright © 2016 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

Intermolecular Interactions between Eosin Y and Caffeine Using 1H-NMR Spectroscopy

Directory of Open Access Journals (Sweden)

Macduff O. Okuom

2013-01-01

Full Text Available DETECHIP has been used in testing analytes including caffeine, cocaine, and tetrahydrocannabinol (THC from marijuana, as well as date rape and club drugs such as flunitrazepam, gamma-hydroxybutyric acid (GHB, and methamphetamine. This study investigates the intermolecular interaction between DETECHIP sensor eosin Y (DC1 and the analyte (caffeine that is responsible for the fluorescence and color changes observed in the actual array. Using 1H-NMR, 1H-COSY, and 1H-DOSY NMR methods, a proton exchange from C-8 of caffeine to eosin Y is proposed.

The same number of optimized parameters scheme for determining intermolecular interaction energies

DEFF Research Database (Denmark)

Kristensen, Kasper; Ettenhuber, Patrick; Eriksen, Janus Juul

2015-01-01

We propose the Same Number Of Optimized Parameters (SNOOP) scheme as an alternative to the counterpoise method for treating basis set superposition errors in calculations of intermolecular interaction energies. The key point of the SNOOP scheme is to enforce that the number of optimized wave...... as numerically. Numerical results for second-order Møller-Plesset perturbation theory (MP2) and coupled-cluster with single, double, and approximate triple excitations (CCSD(T)) show that the SNOOP scheme in general outperforms the uncorrected and counterpoise approaches. Furthermore, we show that SNOOP...

Skin appendage-derived stem cells: cell biology and potential for wound repair.

Science.gov (United States)

Xie, Jiangfan; Yao, Bin; Han, Yutong; Huang, Sha; Fu, Xiaobing

2016-01-01

Stem cells residing in the epidermis and skin appendages are imperative for skin homeostasis and regeneration. These stem cells also participate in the repair of the epidermis after injuries, inducing restoration of tissue integrity and function of damaged tissue. Unlike epidermis-derived stem cells, comprehensive knowledge about skin appendage-derived stem cells remains limited. In this review, we summarize the current knowledge of skin appendage-derived stem cells, including their fundamental characteristics, their preferentially expressed biomarkers, and their potential contribution involved in wound repair. Finally, we will also discuss current strategies, future applications, and limitations of these stem cells, attempting to provide some perspectives on optimizing the available therapy in cutaneous repair and regeneration.

Highly Convergent Total Synthesis of (+)-Lithospermic Acid via a Late-Stage Intermolecular C–H Olefination

Science.gov (United States)

Wang, Dong-Hui; Yu, Jin-Quan

2011-01-01

The total synthesis of (+)-lithospermic acid is reported, which exploits two successive C–H activation reactions as the key steps. Rh-catalyzed carbene C–H insertion reaction using Davies’ catalyst built the dihydrobenzofuran core, and a late-stage intermolecular C–H olefination coupled the olefin unit with the dihydrobenzofuran core to construct the molecule in a highly convergent manner. PMID:21443224

An Efficient Method to Evaluate Intermolecular Interaction Energies in Large Systems Using Overlapping Multicenter ONIOM and the Fragment Molecular Orbital Method

Science.gov (United States)

Asada, Naoya; Fedorov, Dmitri G.; Kitaura, Kazuo; Nakanishi, Isao; Merz, Kenneth M.

2012-01-01

We propose an approach based on the overlapping multicenter ONIOM to evaluate intermolecular interaction energies in large systems and demonstrate its accuracy on several representative systems in the complete basis set limit at the MP2 and CCSD(T) level of theory. In the application to the intermolecular interaction energy between insulin dimer and 4′-hydroxyacetanilide at the MP2/CBS level, we use the fragment molecular orbital method for the calculation of the entire complex assigned to the lowest layer in three-layer ONIOM. The developed method is shown to be efficient and accurate in the evaluation of the protein-ligand interaction energies. PMID:23050059

TOWARDS PHASE TRANSFERABLE POTENTIAL FUNCTIONS - METHODOLOGY AND APPLICATION TO NITROGEN

NARCIS (Netherlands)

JORDAN, PC; VAN MAAREN, PJ; MAVRI, J; VAN DER SPOEL, D; BERENDSEN, HJC

1995-01-01

We describe a generalizable approach to the development of phase transferable effective intermolecular potentials and apply the method to the study of N-2 The method is based on a polarizable shell model description of the isolated molecule and uses experimental data to establish the parameters.

Chondrogenic potential of physically treated bovine cartilage matrix derived porous scaffolds on human dermal fibroblast cells.

Science.gov (United States)

Moradi, Ali; Ataollahi, Forough; Sayar, Katayoun; Pramanik, Sumit; Chong, Pan-Pan; Khalil, Alizan Abdul; Kamarul, Tunku; Pingguan-Murphy, Belinda

2016-01-01

Extracellular matrices have drawn attention in tissue engineering as potential biomaterials for scaffold fabrication because of their bioactive components. Noninvasive techniques of scaffold fabrication and cross-linking treatments are believed to maintain the integrity of bioactive molecules while providing proper architectural and mechanical properties. Cartilage matrix derived scaffolds are designed to support the maintenance of chondrocytes and provide proper signals for differentiation of chondroinducible cells. Chondroinductive potential of bovine articular cartilage matrix derived porous scaffolds on human dermal fibroblasts and the effect of scaffold shrinkage on chondrogenesis were investigated. An increase in sulfated glycosaminoglycans production along with upregulation of chondrogenic genes confirmed that physically treated cartilage matrix derived scaffolds have chondrogenic potential on human dermal fibroblasts. © 2015 Wiley Periodicals, Inc.

Rubrene: The interplay between intramolecular and intermolecular interactions determines the planarization of its tetracene core in the solid state

KAUST Repository

Sutton, Christopher; Marshall, Michael S.; Sherrill, C. David; Risko, Chad; Bredas, Jean-Luc

2015-01-01

exchange-repulsion interactions among the phenyl side groups. Calculations based on available crystallographic structures reveal that planar conformations of the tetracene core in the solid state result from intermolecular interactions that can be tuned

Microscopic optical potentials derived from ab initio translationally invariant nonlocal one-body densities

Science.gov (United States)

Gennari, Michael; Vorabbi, Matteo; Calci, Angelo; Navrátil, Petr

2018-03-01

Background: The nuclear optical potential is a successful tool for the study of nucleon-nucleus elastic scattering and its use has been further extended to inelastic scattering and other nuclear reactions. The nuclear density of the target nucleus is a fundamental ingredient in the construction of the optical potential and thus plays an important role in the description of the scattering process. Purpose: In this paper we derive a microscopic optical potential for intermediate energies using ab initio translationally invariant nonlocal one-body nuclear densities computed within the no-core shell model (NCSM) approach utilizing two- and three-nucleon chiral interactions as the only input. Methods: The optical potential is derived at first order within the spectator expansion of the nonrelativistic multiple scattering theory by adopting the impulse approximation. Nonlocal nuclear densities are derived from the NCSM one-body densities calculated in the second quantization. The translational invariance is generated by exactly removing the spurious center-of-mass (COM) component from the NCSM eigenstates. Results: The ground-state local and nonlocal densities of He 4 ,6 ,8 , 12C, and 16O are calculated and applied to optical potential construction. The differential cross sections and the analyzing powers for the elastic proton scattering off these nuclei are then calculated for different values of the incident proton energy. The impact of nonlocality and the COM removal is discussed. Conclusions: The use of nonlocal densities has a substantial impact on the differential cross sections and improves agreement with experiment in comparison to results generated with the local densities especially for light nuclei. For the halo nuclei 6He and 8He, the results for the differential cross section are in a reasonable agreement with the data although a more sophisticated model for the optical potential is required to properly describe the analyzing powers.

Metal-Catalyzed Intra- and Intermolecular Addition of Carboxylic Acids to Alkynes in Aqueous Media: A Review

Directory of Open Access Journals (Sweden)

Javier Francos

2017-11-01

Full Text Available The metal-catalyzed addition of carboxylic acids to alkynes is a very effective tool for the synthesis of carboxylate-functionalized olefinic compounds in an atom-economical manner. Thus, a large variety of synthetically useful lactones and enol-esters can be accessed through the intra- or intermolecular versions of this process. In order to reduce the environmental impact of these reactions, considerable efforts have been devoted in recent years to the development of catalytic systems able to operate in aqueous media, which represent a real challenge taking into account the tendency of alkynes to undergo hydration in the presence of transition metals. Despite this, different Pd, Pt, Au, Cu and Ru catalysts capable of promoting the intra- and intermolecular addition of carboxylic acids to alkynes in a selective manner in aqueous environments have appeared in the literature. In this review article, an overview of this chemistry is provided. The synthesis of β-oxo esters by catalytic addition of carboxylic acids to terminal propargylic alcohols in water is also discussed.

Structural changes and intermolecular interactions of filled ice Ic structure for hydrogen hydrate under high pressure

International Nuclear Information System (INIS)

Machida, S; Hirai, H; Kawamura, T; Yamamoto, Y; Yagi, T

2010-01-01

High-pressure experiments of hydrogen hydrate were performed using a diamond anvil cell under conditions of 0.1-44.2 GPa and at room temperature. Also, high pressure Raman studies of solid hydrogen were performed in the pressure range of 0.1-43.7 GPa. X-ray diffractometry (XRD) for hydrogen hydrate revealed that a known high-pressure structure, filled ice Ic structure, of hydrogen hydrate transformed to a new high-pressure structure at approximately 35-40 GPa. A comparison of the Raman spectroscopy of a vibron for hydrogen molecules between hydrogen hydrate and solid hydrogen revealed that the extraction of hydrogen molecules from hydrogen hydrate occurred above 20 GPa. Also, the Raman spectra of a roton revealed that the rotation of hydrogen molecules in hydrogen hydrate was suppressed at around 20 GPa and that the rotation recovered under higher pressure. These results indicated that remarkable intermolecular interactions in hydrogen hydrate between neighboring hydrogen molecules and between guest hydrogen molecules and host water molecules might occur. These intermolecular interactions could produce the stability of hydrogen hydrate.

Improved effective potential in curved spacetime and quantum matter--higher derivative gravity theory

International Nuclear Information System (INIS)

Elizalde, E.; Odintsov, S.D.; Romeo, A.

1995-01-01

We develop a general formalism to study the renormalization-group- (RG-)improved effective potential for renormalizable gauge theories, including matter-R 2 -gravity, in curved spacetime. The result is given up to quadratic terms in curvature, and one-loop effective potentials may be easily obtained from it. As an example, we consider scalar QED, where dimensional transmutation in curved space and the phase structure of the potential (in particular, curvature-induced phase transitions) are discussed. For scalar QED with higher-derivative quantum gravity (QG), we examine the influence of QG on dimensional transmutation and calculate QG corrections to the scalar-to-vector mass ratio. The phase structure of the RG-improved effective potential is also studied in this case, and the values of the induced Newton and cosmological coupling constants at the critical point are estimated. The stability of the running scalar coupling in the Yukawa theory with conformally invariant higher-derivative QG, and in the standard model with the same addition, is numerically analyzed. We show that, in these models, QG tends to make the scalar sector less unstable

Organophotocatalysis: Insights into the Mechanistic Aspects of Thiourea-Mediated Intermolecular [2+2] Photocycloadditions.

Science.gov (United States)

Vallavoju, Nandini; Selvakumar, Sermadurai; Pemberton, Barry C; Jockusch, Steffen; Sibi, Mukund P; Sivaguru, Jayaraman

2016-04-25

Mechanistic investigations of the intermolecular [2+2] photocycloaddition of coumarin with tetramethylethylene mediated by thiourea catalysts reveal that the reaction is enabled by a combination of minimized aggregation, enhanced intersystem crossing, and altered excited-state lifetime(s). These results clarify how the excited-state reactivity can be manipulated through catalyst-substrate interactions and reveal a third mechanistic pathway for thiourea-mediated organo-photocatalysis. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Extended Ladder-Type Benzo[ k ]tetraphene-Derived Oligomers

Energy Technology Data Exchange (ETDEWEB)

Lee, Jongbok [Department of Chemistry, Texas A& M University, 3255 TAMU College Station TX 77843-3255 USA; Li, Huanbin [MOE Key Laboratory of Macromolecular Synthesis and Functionalization, State Key Laboratory of Silicon Materials, Department of Polymer Science and Engineering, Zhejiang University, 38 Zheda Rd Hangzhou 310027 China; Kalin, Alexander J. [Department of Chemistry, Texas A& M University, 3255 TAMU College Station TX 77843-3255 USA; Yuan, Tianyu [Department of Materials Science and Engineering, Texas A& M University, 3003 TAMU College Station TX 77843-3003 USA; Wang, Chenxu [Department of Materials Science and Engineering, Texas A& M University, 3003 TAMU College Station TX 77843-3003 USA; Olson, Troy [Department of Chemistry, Texas A& M University, 3255 TAMU College Station TX 77843-3255 USA; Li, Hanying [MOE Key Laboratory of Macromolecular Synthesis and Functionalization, State Key Laboratory of Silicon Materials, Department of Polymer Science and Engineering, Zhejiang University, 38 Zheda Rd Hangzhou 310027 China; Fang, Lei [Department of Chemistry, Texas A& M University, 3255 TAMU College Station TX 77843-3255 USA; Department of Materials Science and Engineering, Texas A& M University, 3003 TAMU College Station TX 77843-3003 USA

2017-10-02

Well-defined, fused-ring aromatic oligomers represent promising candidates for the fundamental understanding and application of advanced carbon-rich materials, though bottom-up synthesis and structure–property correlation of these compounds remain challenging. In this work, an efficient synthetic route was employed to construct extended benzo[k]tetraphene-derived oligomers with up to 13 fused rings. The molecular and electronic structures of these compounds were clearly elucidated. Precise correlation of molecular sizes and crystallization dynamics was established, thus demonstrating the pivotal balance between intermolecular interaction and molecular mobility for optimized processing of highly ordered solids of these extended conjugated molecules.

Similarity-transformed perturbation theory on top of truncated local coupled cluster solutions: Theory and applications to intermolecular interactions

Energy Technology Data Exchange (ETDEWEB)

Azar, Richard Julian, E-mail: julianazar2323@berkeley.edu; Head-Gordon, Martin, E-mail: mhg@cchem.berkeley.edu [Kenneth S. Pitzer Center for Theoretical Chemistry, Department of Chemistry, University of California and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

2015-05-28

Your correspondents develop and apply fully nonorthogonal, local-reference perturbation theories describing non-covalent interactions. Our formulations are based on a Löwdin partitioning of the similarity-transformed Hamiltonian into a zeroth-order intramonomer piece (taking local CCSD solutions as its zeroth-order eigenfunction) plus a first-order piece coupling the fragments. If considerations are limited to a single molecule, the proposed intermolecular similarity-transformed perturbation theory represents a frozen-orbital variant of the “(2)”-type theories shown to be competitive with CCSD(T) and of similar cost if all terms are retained. Different restrictions on the zeroth- and first-order amplitudes are explored in the context of large-computation tractability and elucidation of non-local effects in the space of singles and doubles. To accurately approximate CCSD intermolecular interaction energies, a quadratically growing number of variables must be included at zeroth-order.

Derivative discontinuity and exchange-correlation potential of meta-GGAs in density-functional theory.

Science.gov (United States)

Eich, F G; Hellgren, Maria

2014-12-14

We investigate fundamental properties of meta-generalized-gradient approximations (meta-GGAs) to the exchange-correlation energy functional, which have an implicit density dependence via the Kohn-Sham kinetic-energy density. To this purpose, we construct the most simple meta-GGA by expressing the local exchange-correlation energy per particle as a function of a fictitious density, which is obtained by inverting the Thomas-Fermi kinetic-energy functional. This simple functional considerably improves the total energy of atoms as compared to the standard local density approximation. The corresponding exchange-correlation potentials are then determined exactly through a solution of the optimized effective potential equation. These potentials support an additional bound state and exhibit a derivative discontinuity at integer particle numbers. We further demonstrate that through the kinetic-energy density any meta-GGA incorporates a derivative discontinuity. However, we also find that for commonly used meta-GGAs the discontinuity is largely underestimated and in some cases even negative.

Derivative discontinuity and exchange-correlation potential of meta-GGAs in density-functional theory

International Nuclear Information System (INIS)

Eich, F. G.; Hellgren, Maria

2014-01-01

We investigate fundamental properties of meta-generalized-gradient approximations (meta-GGAs) to the exchange-correlation energy functional, which have an implicit density dependence via the Kohn-Sham kinetic-energy density. To this purpose, we construct the most simple meta-GGA by expressing the local exchange-correlation energy per particle as a function of a fictitious density, which is obtained by inverting the Thomas-Fermi kinetic-energy functional. This simple functional considerably improves the total energy of atoms as compared to the standard local density approximation. The corresponding exchange-correlation potentials are then determined exactly through a solution of the optimized effective potential equation. These potentials support an additional bound state and exhibit a derivative discontinuity at integer particle numbers. We further demonstrate that through the kinetic-energy density any meta-GGA incorporates a derivative discontinuity. However, we also find that for commonly used meta-GGAs the discontinuity is largely underestimated and in some cases even negative

Probing intermolecular protein-protein interactions in the calcium-sensing receptor homodimer using bioluminescence resonance energy transfer (BRET)

DEFF Research Database (Denmark)

Jensen, Anders A.; Hansen, Jakob L; Sheikh, Søren P

2002-01-01

-induced intermolecular movements in the CaR homodimer using the new bioluminescence resonance energy transfer technique, BRET2, which is based on the transference of energy from Renilla luciferase (Rluc) to the green fluorescent protein mutant GFP2. We tagged CaR with Rluc and GFP2 at different intracellular locations...

Amniotic membrane-derived stem cells: immunomodulatory properties and potential clinical application

Directory of Open Access Journals (Sweden)

Insausti CL

2014-03-01

Full Text Available Carmen L Insausti,1 Miguel Blanquer,1 Ana M García-Hernández,1 Gregorio Castellanos,2 José M Moraleda11Unidad de Trasplante Hematopoyético y Terapia Celular, 2Servicio de Cirugía, Hospital Clínico Universitario Virgen de la Arrixaca, IMIB, Campus Mare Nostrum, Universidad de Murcia, El Palmar, Murcia, SpainAbstract: Epithelial and mesenchymal cells isolated from the amniotic membrane (AM possess stem cell characteristics, differentiation potential toward lineages of different germ layers, and immunomodulatory properties. While their expansion and differentiation potential have been well studied and characterized, knowledge about their immunomodulatory properties and the mechanisms involved is still incomplete. These mechanisms have been evaluated on various target cells of the innate and the adaptive system and in animal models of different inflammatory diseases. Some results have evidenced that the immunomodulatory effect of AM-derived cells is dependent on cell-cell contact, but many of them have demonstrated that these properties are mediated through the secretion of suppressive molecules. In this review, we present an update on the described immunomodulatory properties of the derived amniotic cells and some of the proposed involved mechanisms. Furthermore, we describe some assays in animal models of different inflammatory diseases which reveal the potential use of these cells to treat such diseases.Keywords: epithelial cells, mesenchymal cells, cell therapy, immunomodulation

Influence of intramolecular hydrogen bonds on the binding potential of methylated β-cyclodextrin derivatives

Directory of Open Access Journals (Sweden)

Gerhard Wenz

2012-11-01

Full Text Available Various heptasubstituted derivatives of β-cyclodextrin (β-CD bearing 1, 2 and 3 methyl substituents per glucose unit were synthesized by regioselective methods. Binding free energies and binding enthalpies of these hosts towards 4-tert-butylbenzoate and adamantane-1-carboxylate were determined by isothermal titration microcalorimetry (ITC. It was found that methyl substituents at the secondary positions of β-CD lead to a tremendous reduction of the binding potential, while methylation at the primary positions significantly improved binding. Stabilizing intramolecular hydrogen bonds between the glucose units were made responsible for the high binding potentials of those β-CD derivatives that possess secondary hydroxy groups.

Correction for dispersion and Coulombic interactions in molecular clusters with density functional derived methods: Application to polycyclic aromatic hydrocarbon clusters

Science.gov (United States)

Rapacioli, Mathias; Spiegelman, Fernand; Talbi, Dahbia; Mineva, Tzonka; Goursot, Annick; Heine, Thomas; Seifert, Gotthard

2009-06-01

The density functional based tight binding (DFTB) is a semiempirical method derived from the density functional theory (DFT). It inherits therefore its problems in treating van der Waals clusters. A major error comes from dispersion forces, which are poorly described by commonly used DFT functionals, but which can be accounted for by an a posteriori treatment DFT-D. This correction is used for DFTB. The self-consistent charge (SCC) DFTB is built on Mulliken charges which are known to give a poor representation of Coulombic intermolecular potential. We propose to calculate this potential using the class IV/charge model 3 definition of atomic charges. The self-consistent calculation of these charges is introduced in the SCC procedure and corresponding nuclear forces are derived. Benzene dimer is then studied as a benchmark system with this corrected DFTB (c-DFTB-D) method, but also, for comparison, with the DFT-D. Both methods give similar results and are in agreement with references calculations (CCSD(T) and symmetry adapted perturbation theory) calculations. As a first application, pyrene dimer is studied with the c-DFTB-D and DFT-D methods. For coronene clusters, only the c-DFTB-D approach is used, which finds the sandwich configurations to be more stable than the T-shaped ones.

Derivatives of phenyl tribromomethyl sulfone as novel compounds with potential pesticidal activity

Directory of Open Access Journals (Sweden)

Krzysztof M. Borys

2012-02-01

Full Text Available A halogenmethylsulfonyl moiety is incorporated in numerous active herbicides and fungicides. The synthesis of tribromomethyl phenyl sulfone derivatives as novel potential pesticides is reported. The title sulfone was obtained by following three different synthetic routes, starting from 4-chlorothiophenol or 4-halogenphenyl methyl sulfone. Products of its subsequent nitration were subjected to the SNAr reactions with ammonia, amines, hydrazines and phenolates to give 2-nitroaniline, 2-nitrophenylhydrazine and diphenyl ether derivatives. Reduction of the nitro group of 4-tribromomethylsulfonyl-2-nitroaniline yielded the corresponding o-phenylenediamine substrate for preparation of structurally varied benzimidazoles.

Oleanolic Acid and Its Derivatives: Biological Activities and Therapeutic Potential in Chronic Diseases

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Taiwo Betty Ayeleso

2017-11-01

Full Text Available The increasing demand for natural products as an alternative therapy for chronic diseases has encouraged research into the pharmacological importance of bioactive compounds from plants. Recently, there has been a surge of interest in the therapeutic potential of oleanolic acid (OA in the prevention and management of chronic diseases. Oleanolic acid is a pentacyclic triterpenoid widely found in plants, including fruits and vegetables with different techniques and chromatography platforms being employed in its extraction and isolation. Several studies have demonstrated the potential therapeutic effects of OA on different diseases and their symptoms. Furthermore, oleanolic acid also serves as a framework for the development of novel semi-synthetic triterpenoids that could prove vital in finding therapeutic modalities for various ailments. There are recent advances in the design and synthesis of chemical derivatives of OA to enhance its solubility, bioavailability and potency. Some of these derivatives have also been therapeutic candidates in a number of clinical trials. This review consolidates and expands on recent reports on the biological effects of oleanolic acid from different plant sources and its synthetic derivatives as well as their mechanisms of action in in vitro and in vivo study models. This review suggests that oleanolic acid and its derivatives are important candidates in the search for alternative therapy in the treatment and management of chronic diseases.

Effect of surface tension on the behavior of adhesive contact based on Lennard-Jones potential law

Science.gov (United States)

Zhu, Xinyao; Xu, Wei

2018-02-01

The present study explores the effect of surface tension on adhesive contact behavior where the adhesion is interpreted by long-range intermolecular forces. The adhesive contact is analyzed using the equivalent system of a rigid sphere and an elastic half space covered by a membrane with surface tension. The long-range intermolecular forces are modeled with the Lennard‒Jones (L‒J) potential law. The current adhesive contact issue can be represented by a nonlinear integral equation, which can be solved by Newton‒Raphson method. In contrast to previous studies which consider intermolecular forces as short-range, the present study reveals more details of the features of adhesive contact with surface tension, in terms of jump instabilities, pull-off forces, pressure distribution within the contact area, etc. The transition of the pull-off force is not only consistent with previous studies, but also presents some new interesting characteristics in the current situation.

Intermolecular Interactions in Ternary Glycerol–Sample–H2O

DEFF Research Database (Denmark)

Westh, Peter; Rasmussen, Erik Lumby; Koga, Yoshikata

2011-01-01

We studied the intermolecular interactions in ternary glycerol (Gly)–sample (S)–H2O systems at 25 °C. By measuring the excess partial molar enthalpy of Gly, HGlyEHEGly, we evaluated the Gly–Gly enthalpic interaction, HGly-GlyEHEGly--Gly, in the presence of various samples (S). For S, tert...... little effect on HGly-GlyEHEGly--Gly. This contrasts with our earlier studies on 1P–S–H2O in that Na+, F− and Cl− are found as hydration centers from the induced changes on HIP-IPEHEIP--IP in the presence of S, while Br−, I−, and SCN− are found to act as hydrophiles. In comparison with the Hofmeister...... ranking of these ions, the kosmotropes are hydration centers and the more kosmotropic the higher the hydration number, consistent with the original Hofmeister’s concept of “H2O withdrawing power.” Br−, I− and SCN−, on the other hand, acted as hydrophiles and the more chaotropic they are the more...

Simulations of molecular self-assembled monolayers on surfaces: packing structures, formation processes and functions tuned by intermolecular and interfacial interactions.

Science.gov (United States)

Wen, Jin; Li, Wei; Chen, Shuang; Ma, Jing

2016-08-17

Surfaces modified with a functional molecular monolayer are essential for the fabrication of nano-scale electronics or machines with novel physical, chemical, and/or biological properties. Theoretical simulation based on advanced quantum chemical and classical models is at present a necessary tool in the development, design, and understanding of the interfacial nanostructure. The nanoscale surface morphology, growth processes, and functions are controlled by not only the electronic structures (molecular energy levels, dipole moments, polarizabilities, and optical properties) of building units but also the subtle balance between intermolecular and interfacial interactions. The switchable surfaces are also constructed by introducing stimuli-responsive units like azobenzene derivatives. To bridge the gap between experiments and theoretical models, opportunities and challenges for future development of modelling of ferroelectricity, entropy, and chemical reactions of surface-supported monolayers are also addressed. Theoretical simulations will allow us to obtain important and detailed information about the structure and dynamics of monolayer modified interfaces, which will guide the rational design and optimization of dynamic interfaces to meet challenges of controlling optical, electrical, and biological functions.

Intermolecular symmetry-adapted perturbation theory study of large organic complexes

International Nuclear Information System (INIS)

Heßelmann, Andreas; Korona, Tatiana

2014-01-01

Binding energies for the complexes of the S12L database by Grimme [Chem. Eur. J. 18, 9955 (2012)] were calculated using intermolecular symmetry-adapted perturbation theory combined with a density-functional theory description of the interacting molecules. The individual interaction energy decompositions revealed no particular change in the stabilisation pattern as compared to smaller dimer systems at equilibrium structures. This demonstrates that, to some extent, the qualitative description of the interaction of small dimer systems may be extrapolated to larger systems, a method that is widely used in force-fields in which the total interaction energy is decomposed into atom-atom contributions. A comparison of the binding energies with accurate experimental reference values from Grimme, the latter including thermodynamic corrections from semiempirical calculations, has shown a fairly good agreement to within the error range of the reference binding energies

INS study of intermolecular interaction at the silicone-fumed silica interface

International Nuclear Information System (INIS)

Sheka, E.F.; Natkaniec, I.

1999-01-01

Complete text of publication follows. The paper presents results related to the interface formed between finned silica particles and polydimethylsiloxane polymers, presented in the study by a five-member cyclic oligomer SiS. The substrate surface is terminated by either hydroxyl units or by trimethylsiloxy ones. When the interface is formed, methyl units are the main constituents providing neutron scattering. Protium/deuterium exchange has been used to distinguish the latter belonging to either adsorbate or substrate. A detailed analysis of the intermolecular interaction impact on both adsorbed molecule and substrate has been performed. The observed features are supported by the vibrational spectra calculations performed on the basis of a modem quantum-chemical approach and supplemented by the solution of the inverse spectral problem. (author)

Quantum mechanical calculations on weakly interacting complexes

NARCIS (Netherlands)

Heijmen, T.G.A.

1998-01-01

Symmetry-adapted perturbation theory (SAPT) has been applied to compute the intermolecular potential energy surfaces and the interaction-induced electrical properties of weakly interacting complexes. Asymptotic (large R) expressions have been derived for the contributions to the collision-induced

Solar resources and power potential mapping in Vietnam using satellite-derived and GIS-based information

International Nuclear Information System (INIS)

Polo, J.; Bernardos, A.; Navarro, A.A.; Fernandez-Peruchena, C.M.; Ramírez, L.; Guisado, María V.; Martínez, S.

2015-01-01

Highlights: • Satellite-based, reanalysis data and measurements are combined for solar mapping. • Plant output modeling for PV and CSP results in simple expressions of solar potential. • Solar resource, solar potential are used in a GIS for determine technical solar potential. • Solar resource and potential maps of Vietnam are presented. - Abstract: The present paper presents maps of the solar resources in Vietnam and of the solar potential for concentrating solar power (CSP) and for grid-connected photovoltaic (PV) technology. The mapping of solar radiation components has been calculated from satellite-derived data combined with solar radiation derived from sunshine duration and other additional sources of information based on reanalysis for several atmospheric and meteorological parameters involved. Two scenarios have been selected for the study of the solar potential: CSP Parabolic Trough of 50 MWe and grid-connected Flat Plate PV plant of around 1 MWe. For each selected scenario plant performance simulations have been computed for developing simple expressions that allow the estimation of the solar potential from the annual solar irradiation and the latitude of every site in Vietnam. Finally, Geographic Information Systems (GIS) have been used for combining the solar potential with the land availability according each scenario to deliver the technical solar potential maps of Vietnam

Myocardial regeneration potential of adipose tissue-derived stem cells

Energy Technology Data Exchange (ETDEWEB)

Bai, Xiaowen, E-mail: baixw01@yahoo.com [Department of Molecular Pathology, The University of Texas M.D. Anderson Cancer Center, 1515 Holcombe, Houston, TX 77030 (United States); Alt, Eckhard, E-mail: ealt@mdanderson.org [Department of Molecular Pathology, The University of Texas M.D. Anderson Cancer Center, 1515 Holcombe, Houston, TX 77030 (United States)

2010-10-22

Research highlights: {yields} Various tissue resident stem cells are receiving tremendous attention from basic scientists and clinicians and hold great promise for myocardial regeneration. {yields} For practical reasons, human adipose tissue-derived stem cells are attractive stem cells for future clinical application in repairing damaged myocardium. {yields} This review summarizes the characteristics of cultured and freshly isolated stem cells obtained from adipose tissue, their myocardial regeneration potential and the, underlying mechanisms, and safety issues. -- Abstract: Various tissue resident stem cells are receiving attention from basic scientists and clinicians as they hold promise for myocardial regeneration. For practical reasons, adipose tissue-derived stem cells (ASCs) are attractive cells for clinical application in repairing damaged myocardium based on the following advantages: abundant adipose tissue in most patients and easy accessibility with minimally invasive lipoaspiration procedure. Several recent studies have demonstrated that both cultured and freshly isolated ASCs could improve cardiac function in animal model of myocardial infarction. The mechanisms underlying the beneficial effect of ASCs on myocardial regeneration are not fully understood. Growing evidence indicates that transplantation of ASCs improve cardiac function via the differentiation into cardiomyocytes and vascular cells, and through paracrine pathways. Paracrine factors secreted by injected ASCs enhance angiogenesis, reduce cell apoptosis rates, and promote neuron sprouts in damaged myocardium. In addition, Injection of ASCs increases electrical stability of the injured heart. Furthermore, there are no reported cases of arrhythmia or tumorigenesis in any studies regarding myocardial regeneration with ASCs. This review summarizes the characteristics of both cultured and freshly isolated stem cells obtained from adipose tissue, their myocardial regeneration potential, and the

Myocardial regeneration potential of adipose tissue-derived stem cells

International Nuclear Information System (INIS)

Bai, Xiaowen; Alt, Eckhard

2010-01-01

Research highlights: → Various tissue resident stem cells are receiving tremendous attention from basic scientists and clinicians and hold great promise for myocardial regeneration. → For practical reasons, human adipose tissue-derived stem cells are attractive stem cells for future clinical application in repairing damaged myocardium. → This review summarizes the characteristics of cultured and freshly isolated stem cells obtained from adipose tissue, their myocardial regeneration potential and the, underlying mechanisms, and safety issues. -- Abstract: Various tissue resident stem cells are receiving attention from basic scientists and clinicians as they hold promise for myocardial regeneration. For practical reasons, adipose tissue-derived stem cells (ASCs) are attractive cells for clinical application in repairing damaged myocardium based on the following advantages: abundant adipose tissue in most patients and easy accessibility with minimally invasive lipoaspiration procedure. Several recent studies have demonstrated that both cultured and freshly isolated ASCs could improve cardiac function in animal model of myocardial infarction. The mechanisms underlying the beneficial effect of ASCs on myocardial regeneration are not fully understood. Growing evidence indicates that transplantation of ASCs improve cardiac function via the differentiation into cardiomyocytes and vascular cells, and through paracrine pathways. Paracrine factors secreted by injected ASCs enhance angiogenesis, reduce cell apoptosis rates, and promote neuron sprouts in damaged myocardium. In addition, Injection of ASCs increases electrical stability of the injured heart. Furthermore, there are no reported cases of arrhythmia or tumorigenesis in any studies regarding myocardial regeneration with ASCs. This review summarizes the characteristics of both cultured and freshly isolated stem cells obtained from adipose tissue, their myocardial regeneration potential, and the underlying

Ab initio intermolecular potential energy surface and thermophysical properties of hydrogen sulfide.

Science.gov (United States)

Hellmann, Robert; Bich, Eckard; Vogel, Eckhard; Vesovic, Velisa

2011-08-14

A six-dimensional potential energy hypersurface (PES) for two interacting rigid hydrogen sulfide molecules was determined from high-level quantum-mechanical ab initio computations. A total of 4016 points for 405 different angular orientations of two molecules were calculated utilizing the counterpoise-corrected supermolecular approach at the CCSD(T) level of theory and extrapolating the calculated interaction energies to the complete basis set limit. An analytical site-site potential function with eleven sites per hydrogen sulfide molecule was fitted to the interaction energies. The PES has been validated by computing the second pressure virial coefficient, shear viscosity, thermal conductivity and comparing with the available experimental data. The calculated values of volume viscosity were not used to validate the potential as the low accuracy of the available data precluded such an approach. The second pressure virial coefficient was evaluated by means of the Takahashi and Imada approach, while the transport properties, in the dilute limit, were evaluated by utilizing the classical trajectory method. In general, the agreement with the primary experimental data is within the experimental error for temperatures higher than 300 K. For lower temperatures the lack of reliable data indicates that the values of the second pressure virial coefficient and of the transport properties calculated in this work are currently the most accurate estimates for the thermophysical properties of hydrogen sulfide.

Formation of an intermolecular charge-transfer compound in UHV codeposited tetramethoxypyrene and tetracyanoquinodimethane

DEFF Research Database (Denmark)

Medjanik, K.; Perkert, S.; Naghavi, S.

2010-01-01

Ultrahigh vacuum (UHV)-deposited films of the mixed phase of tetramethoxypyrene and tetracyanoquinodimethane (TMP -TCNQ ) on gold have been studied using ultraviolet photoelectron spectroscopy (UPS), x-ray diffraction (XRD), infrared (IR) spectroscopy, and scanning tunneling spectroscopy (STS......). The formation of an intermolecular charge-transfer (CT) compound is evident from the appearance of new reflexes in XRD (d =0.894nm and d =0.677nm). A softening of the CN stretching vibration (redshift by 7 cm⊃-1) of TCNQ is visible in the IR spectra, being indicative of a CT on the order of 0.3e from TMP...

A general approach to intermolecular carbonylation of arene C-H bonds to ketones through catalytic aroyl triflate formation

Science.gov (United States)

Garrison Kinney, R.; Tjutrins, Jevgenijs; Torres, Gerardo M.; Liu, Nina Jiabao; Kulkarni, Omkar; Arndtsen, Bruce A.

2018-02-01

The development of metal-catalysed methods to functionalize inert C-H bonds has become a dominant research theme in the past decade as an approach to efficient synthesis. However, the incorporation of carbon monoxide into such reactions to form valuable ketones has to date proved a challenge, despite its potential as a straightforward and green alternative to Friedel-Crafts reactions. Here we describe a new approach to palladium-catalysed C-H bond functionalization in which carbon monoxide is used to drive the generation of high-energy electrophiles. This offers a method to couple the useful features of metal-catalysed C-H functionalization (stable and available reagents) and electrophilic acylations (broad scope and selectivity), and synthesize ketones simply from aryl iodides, CO and arenes. Notably, the reaction proceeds in an intermolecular fashion, without directing groups and at very low palladium-catalyst loadings. Mechanistic studies show that the reaction proceeds through the catalytic build-up of potent aroyl triflate electrophiles.

Quantitative assessment of intermolecular interactions by atomic force microscopy imaging using copper oxide tips

Science.gov (United States)

Mönig, Harry; Amirjalayer, Saeed; Timmer, Alexander; Hu, Zhixin; Liu, Lacheng; Díaz Arado, Oscar; Cnudde, Marvin; Strassert, Cristian Alejandro; Ji, Wei; Rohlfing, Michael; Fuchs, Harald

2018-05-01

Atomic force microscopy is an impressive tool with which to directly resolve the bonding structure of organic compounds1-5. The methodology usually involves chemical passivation of the probe-tip termination by attaching single molecules or atoms such as CO or Xe (refs 1,6-9). However, these probe particles are only weakly connected to the metallic apex, which results in considerable dynamic deflection. This probe particle deflection leads to pronounced image distortions, systematic overestimation of bond lengths, and in some cases even spurious bond-like contrast features, thus inhibiting reliable data interpretation8-12. Recently, an alternative approach to tip passivation has been used in which slightly indenting a tip into oxidized copper substrates and subsequent contrast analysis allows for the verification of an oxygen-terminated Cu tip13-15. Here we show that, due to the covalently bound configuration of the terminal oxygen atom, this copper oxide tip (CuOx tip) has a high structural stability, allowing not only a quantitative determination of individual bond lengths and access to bond order effects, but also reliable intermolecular bond characterization. In particular, by removing the previous limitations of flexible probe particles, we are able to provide conclusive experimental evidence for an unusual intermolecular N-Au-N three-centre bond. Furthermore, we demonstrate that CuOx tips allow the characterization of the strength and configuration of individual hydrogen bonds within a molecular assembly.

Synthesis and description of intermolecular interactions in new sulfonamide derivatives of tranexamic acid

Science.gov (United States)

Ashfaq, Muhammad; Arshad, Muhammad Nadeem; Danish, Muhammad; Asiri, Abdullah M.; Khatoon, Sadia; Mustafa, Ghulam; Zolotarev, Pavel N.; Butt, Rabia Ayub; Şahin, Onur

2016-01-01

Tranexamic acid (4-aminomethyl-cyclohexanecarboxylic acid) was reacted with sulfonyl chlorides to produce structurally related four sulfonamide derivatives using simple and environmental friendly method to check out their three-dimensional behavior and van der Walls interactions. The molecules were crystallized in different possibilities, as it is/after alkylation at its O and N atoms/along with a co-molecule. All molecules were crystallized in monoclinic crystal system with space group P21/n, P21/c and P21/a. X-ray studies reveal that the molecules stabilized themselves by different kinds of hydrogen bonding interactions. The molecules are getting connected through O-H⋯O hydrogen bonds to form inversion dimers which are further connected through N-H⋯O interactions. The molecules in which N and O atoms were alkylated showed non-classical interaction and generated centro-symmetric R22(24) ring motif. The co-crystallized host and guest molecules are connected to each other via O-H⋯O interactions to generate different ring motifs. By means of the ToposPro software an analysis of the topologies of underlying nets that correspond to molecular packings and hydrogen-bonded networks in structures under consideration was carried out.

Waste Derived Sorbents and Their Potential Roles in Heavy Metal Remediation Applications

Directory of Open Access Journals (Sweden)

Chiang Y. W.

2013-04-01

Full Text Available Inorganic waste materials that have the suitable inherent characteristics could be used as precursors for the synthesis of micro- and mesoporous materials, which present great potential to be re-utilized as sorbent materials for heavy metal remediation. Three inorganic waste materials were studied in the present work: water treatment residuals (WTRs from an integrated drinking water/wastewater treatment plant, and fly ash and bottom ash samples from a municipal solid waste incinerator (MSWI. These wastes were converted into three sorbent materials: ferrihydrite-like materials derived from drying of WTRs, hydroxyapatite-like material derived from ultrasound assisted synthesis of MSWI fly ash with phosphoric acid solution, and a zeolitic material derived from alkaline hydrothermal conversion of MSWI bottom ash. The performance of these materials, as well as their equivalent commercially available counterparts, was assessed for the adsorption of multiple heavy metals (As, Cd, Co, Ni, Pb, Zn from synthetic solutions, contaminated sediments and surface waters; and satisfactory results were obtained. In addition, it was observed that the combination of sorbents into sorbent mixtures enhanced the performance levels and, where applicable, stabilized inherently mobile contaminants from the waste derived sorbents.

Syntheses of planar 1,5,2,4,6,8-dithiotetrazocine derivatives and thermodynamic study on intermolecular charge transfer for developing efficient organic solar cell

Energy Technology Data Exchange (ETDEWEB)

Zhang, Chao-Zhi, E-mail: zhangchaozhi@nuist.edu.cn [Department of Chemistry, Nanjing University of Information Science & Technology, Nanjing 210044 (China); Shen, Dan [Department of Chemistry, Nanjing University of Information Science & Technology, Nanjing 210044 (China); Yuan, Yang [Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Nanjing University of Information Science & Technology, Nanjing 210044 (China); Song, Ming-Xia; Li, Shi-Juan [Department of Chemistry, Nanjing University of Information Science & Technology, Nanjing 210044 (China); Cao, Hui, E-mail: yccaoh@hotmail.com [Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Nanjing University of Information Science & Technology, Nanjing 210044 (China)

2016-07-01

A series of planar 1,5,2,4,6,8-dithiotetrazocine derivatives were synthesized for study on charge transfer at donor/acceptor interface. The fluorescence quenching spectra, and the highest occupied molecular orbital (−6.10 ∼ −6.25 eV) and the lowest unoccupied molecular orbital (−3.45 ∼ −3.58 eV) energy levels of these 1,5,2,4,6,8-dithiotetrazocine derivatives show that they would be potential acceptor materials. Based on theoretical calculations, thermodynamic study on charge transfer at donor/acceptor interface was carried out. The results of experiments and theoretical calculations show that the electrons could transfer spontaneously from poly(3-hexylthiophene) to these acceptors. The percentages of fluorescence quenching increase with negative Gibbs free energy values increasing in the charge transfer procedures. Therefore, short circuit current values of organic solar cells would increase with the Gibbs free energy values increasing. This paper suggests a useful way for developing efficient organic solar cells. - Highlights: • Syntheses of planar 1,5,2,4,6,8-dithiotetrazocine derivatives for develop effective acceptor. • Electrons at excited state in P3HT could transfer spontaneously to these acceptors. • Thermodynamic study on charge transfer at donor/acceptor interface. • Short circuit currents would be predicted by Gibbs free energy in procedure of charge transfer.

Crystal structures and intermolecular interactions of two novel antioxidant triazolyl-benzimidazole compounds

International Nuclear Information System (INIS)

Karayel, A.; Özbey, S.; Ayhan-Kılcıgil, G.; Kuş, C.

2015-01-01

The crystal structures of 5-(2-(p-chlorophenylbenzimidazol-1-yl-methyl)-4-(3-fluorophenyl)-2, 4-dihydro-[1,2,4]-triazole-3-thione (G6C) and 5-(2-(p-chlorophenylbenzimidazol-1-yl-methyl)-4-(2-methylphenyl)-2, 4-dihydro-[1,2,4]-triazole-3-thione (G4C) have been determined by single-crystal X-ray diffraction. Benzimidazole ring systems in both molecules are planar. The triazole part is almost perpendicular to the phenyl and the benzimidazole parts of the molecules in order to avoid steric interactions between the rings. The crystal structures are stabilized by intermolecular hydrogen bonds between the amino group of the triazole and the nitrogen atom of benzimidazole of a neighboring molecule

JCZS: An Intermolecular Potential Database for Performing Accurate Detonation and Expansion Calculations

Energy Technology Data Exchange (ETDEWEB)

Baer, M.R.; Hobbs, M.L.; McGee, B.C.

1998-11-03

Exponential-13,6 (EXP-13,6) potential pammeters for 750 gases composed of 48 elements were determined and assembled in a database, referred to as the JCZS database, for use with the Jacobs Cowperthwaite Zwisler equation of state (JCZ3-EOS)~l) The EXP- 13,6 force constants were obtained by using literature values of Lennard-Jones (LJ) potential functions, by using corresponding states (CS) theory, by matching pure liquid shock Hugoniot data, and by using molecular volume to determine the approach radii with the well depth estimated from high-pressure isen- tropes. The JCZS database was used to accurately predict detonation velocity, pressure, and temperature for 50 dif- 3 Accurate predictions were also ferent explosives with initial densities ranging from 0.25 glcm3 to 1.97 g/cm . obtained for pure liquid shock Hugoniots, static properties of nitrogen, and gas detonations at high initial pressures.

Dielectric behaviour and intermolecular association between L(+) ascorbic acid and ethanol

International Nuclear Information System (INIS)

Rudyk, R.A.; Torres, M.C.; Acuna Molina, M.A.

1990-01-01

In order to determine the dipole moment of L(+) ascorbic acid and the relation to its structure the experimental variations of permitivities, refractive indices and specific volumes of a series of dilute ethanolic solutions at 25 deg C were examined. The average moment (μ) using Buckingham equation was found to be 5,58 D considering the spherical approximation and 7,81 D if the ellipsoidal form factor was considered. The calculated μ value through vectorial addition was 4,98 D. The solute partial molal volume in the studied range was calculated to be 94,73 cm 3 instead of the theoretical value of 106,71 cm 3 . Both discrepancies are attributed to intermolecular solute-solvent interactions. A possible electronic displacement which favours hydrogen bonding with the solvent is postulated. (Author) [es

Influence of packing motives on charge Carrier mobility in perylene tetracarboxdiimide derivatives

Energy Technology Data Exchange (ETDEWEB)

May, Falk; Andrienko, Denis [Max-Planck Institute for Polymer Research, Mainz (Germany); Marcon, Valentina [Center of Smart Interfaces, Darmstadt (Germany)

2010-07-01

Discotic mesophases are known for their ability to self-assemble into columnar structures and can serve as semiconducting molecular wires. Charge carrier mobility along these wires strongly depends on molecular packing which is controlled by intermolecular interactions. In this work we compare the influence of side chains on the packing motives of perylene tetracarboxdiimide (PDI) derivatives. Two different (alkyl and glycol) side chains are considered. We first establish how the packing of side chains affects the molecular orientation within the columns using molecular dynamics. Then, using the high temperature non-adiabatic limit of Marcus theory for hopping rates and solving the rate equation for charge transport, we analyze the link between the secondary structure and charge carrier mobility. This analysis eventually provides a pathway to rational design of columnar assemblies of PDI derivatives with high charge mobilities.

Intermolecular proton transfer in anionic complexes of uracil with alcohols

International Nuclear Information System (INIS)

Haranczyk, Maciej; Rak, Janusz; Gutowski, Maciej S.; Radisic, Dunja; Stokes, Sarah T.; Bowen, Kit H.

2005-01-01

A series of eighteen alcohols (ROH) has been designed with an enthalpy of deprotonation (H DP ) in a range of 13.8-16.3 eV. The effects of excess electron attachment to the binary alcohol-uracil (ROH...U) complexes have been studied at the density functional level with a B3LYP exchange-correlation functional and at the second order Moeller-Plesset perturbation theory level. The photoelectron spectra of anionic complexes of uracil with three alcohols (ethanol, 2,2,3,3,3-pentafluoroethanol and 1,1,1,3,3,3-hexafluoro-2-propanol) have been measured with 2.54 eV photons. For ROHs with deprotonation enthalpies larger than 14.8 eV only the ROH...U - minimum exists on the potential energy surface of the anionic complex. For alcohols with deprotonation enthalpies in a range of 14.3-14.8 eV two minima might exist on the anionic potential energy surface, which correspond to the RO - ...HU . and ROH...U - structures. For ROHs with deprotonation enthalpies smaller than 14.3 eV, the excess electron attachment to the ROH...U complex always induces a barrier-free proton transfer from the hydroxyl group of ROH to the O8 atom of U, with the product being RO - ...HU . . A driving force for the intermolecular proton transfer is to stabilize the excess negative charge localized on a orbital of uracil. Therefore, these complexes with proton transferred to the anionic uracil are characterized by larger values of electron vertical detachment energy (VDE). The values of VDE for anionic complexes span a range from 1.0 to 2.3 eV and roughly correlate with the acidity of alcohols. However, there is a gap of ∼0.5 eV in the values of VDE, which separates the two families, ROH...U - and RO - ...HU . , of anionic complexes. The energy of stabilization for the anionic complexes spans a range from 0.6 to 1.7 eV and roughly correlates with the acidity of alcohols. The measured photoelectron spectra are in good agreement with the theoretical predictions

Effects of discontinuities of the derivatives of the inflaton potential

Energy Technology Data Exchange (ETDEWEB)

Cadavid, Alexander Gallego [Instituto de Fisica, Universidad de Antioquia, A.A.1226, Medellin (Colombia); Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto (Japan); Romano, Antonio Enea, E-mail: aer@physics.uoc.gr [Instituto de Fisica, Universidad de Antioquia, A.A.1226, Medellin (Colombia); Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto (Japan); Department of Physics, University of Crete, 71003, Heraklion (Greece)

2015-12-12

We study the effects of a class of features of the inflaton potential, corresponding to discontinuities in its derivatives. We perform fully numerical calculations and derive analytical approximations for the curvature perturbations spectrum and the bispectrum which are in good agreement with the numerical results. The spectrum of primordial perturbations has oscillations around the scale k{sub 0} which leaves the horizon at the time τ{sub 0} when the feature occurs, with the amplitude and phase of the oscillations determined by the size and the order of the discontinuity. The large scale bispectrum in the squeezed and equilateral limits have a very similar form and are linearly suppressed. Both in the squeezed and the equilateral small scale limit the bispectrum has an oscillatory behavior whose phase depends on the parameters determining the discontinuity, and whose amplitude is inversely proportional to the scale. Given the generality of this class of features they could be used to model or classify phenomenologically different types of non-Gaussian features encountered in observational data such as the cosmic microwave background radiation or large scale structure.

Effects of discontinuities of the derivatives of the inflaton potential

Energy Technology Data Exchange (ETDEWEB)

Gallego Cadavid, Alexander [Universidad de Antioquia, Instituto de Fisica, Medellin (Colombia); Kyoto University, Yukawa Institute for Theoretical Physics, Kyoto (Japan); Enea Romano, Antonio [Universidad de Antioquia, Instituto de Fisica, Medellin (Colombia); Kyoto University, Yukawa Institute for Theoretical Physics, Kyoto (Japan); University of Crete, Department of Physics, Heraklion (Greece)

2015-12-15

We study the effects of a class of features of the inflaton potential, corresponding to discontinuities in its derivatives. We perform fully numerical calculations and derive analytical approximations for the curvature perturbations spectrum and the bispectrum which are in good agreement with the numerical results. The spectrum of primordial perturbations has oscillations around the scale k{sub 0} which leaves the horizon at the time τ{sub 0} when the feature occurs, with the amplitude and phase of the oscillations determined by the size and the order of the discontinuity. The large scale bispectrum in the squeezed and equilateral limits have a very similar form and are linearly suppressed. Both in the squeezed and the equilateral small scale limit the bispectrum has an oscillatory behavior whose phase depends on the parameters determining the discontinuity, and whose amplitude is inversely proportional to the scale. Given the generality of this class of features they could be used to model or classify phenomenologically different types of non-Gaussian features encountered in observational data such as the cosmic microwave background radiation or large scale structure. (orig.)

Electron-deficient anthraquinone derivatives as cathodic material for lithium ion batteries

Science.gov (United States)

Takeda, Takashi; Taniki, Ryosuke; Masuda, Asuna; Honma, Itaru; Akutagawa, Tomoyuki

2016-10-01

We studied the electronic and structural properties of electron-deficient anthraquinone (AQ) derivatives, Me4N4AQ and TCNAQ, and investigated their charge-discharge properties in lithium ion batteries along with those of AQ. Cyclic voltammogram, X-ray structure analysis and theoretical calculations revealed that these three acceptors have different features, such as different electron-accepting properties with different reduction processes and lithium coordination abilities, and different packing arrangements with different intermolecular interactions. These differences greatly affect the charge-discharge properties of lithium ion batteries that use these compounds as cathode materials. Among these compounds, Me4N4AQ showed a high charge/discharge voltage (2.9-2.5 V) with high cyclability (>65% of the theoretical capacity after 30 cycles; no decrease after 15 cycles). These results provide insight into more in-depth design principles for lithium ion batteries using AQ derivatives as cathodic materials.

Graphene-enhanced intermolecular interaction at interface between copper- and cobalt-phthalocyanines

Energy Technology Data Exchange (ETDEWEB)

Dou, Wei-Dong [Department of Physics, Shaoxing University, Shaoxing 312000 (China); Center of Super-Diamond and Advanced Films (COSDAF) and Department of Physics and Material Science, City University of Hong Kong, Hong Kong (China); Huang, Shu-Ping [Department of Chemistry, University of South Dakota, Vermillion, South Dakota 57069 (United States); Lee, Chun-Sing, E-mail: apcslee@cityu.edu.hk [Center of Super-Diamond and Advanced Films (COSDAF) and Department of Physics and Material Science, City University of Hong Kong, Hong Kong (China)

2015-10-07

Interfacial electronic structures of copper-phthalocyanine (CuPc), cobalt-phthalocyanine (CoPc), and graphene were investigated experimentally by using photoelectron spectroscopy. While the CuPc/graphene interface shows flat band structure and negligible interfacial dipole indicating quite weak molecule-substrate interaction, the CuPc/CoPc/graphene interface shows a large interfacial dipole and obvious energy level bending. Controlled experiments ruled out possible influences from the change in film structure of CuPc and pure π–π interaction between CoPc and CuPc. Analysis based on X-ray photoelectron spectroscopy and density functional theory reveals that the decrease in the work function for the CuPc/CoPc/graphene system is induced by the intermolecular interaction between CuPc and CoPc which is enhanced owning to the peculiar electronic properties at the CoPc-graphene interface.

Semiclassical derivation of a local optical potential for heavy-ion elastic scattering. [Coupling to other processes

Energy Technology Data Exchange (ETDEWEB)

Donangelo, R; Canto, L F [Rio de Janeiro Univ. (Brazil). Inst. de Fisica; Hussein, M S [Sao Paulo Univ. (Brazil). Inst. de Fisica

1979-05-21

A semiclassical method to determine the contribution to the optical potential in the elastic channel due to the coupling to other processes taking place in heavy-ion collisions is developed. An application is made to the case of Coulomb excitation. The lowest-order term of the potential used is shown to be identical to the potential derived by Baltz et al.

Synthesis, molecular modeling and structural characterization of vanillin derivatives as antimicrobial agents

Science.gov (United States)

Sun, Juan; Yin, Yong; Sheng, Gui-Hua; Yang, Zhi-Bo; Zhu, Hai-Liang

2013-05-01

Two vanillin derivatives have been designed and synthesized and their biological activities were also evaluated for antimicrobial activity. Their chemical structures are characterized by single crystal X-ray diffraction studies, 1H NMR, MS, and elemental analysis. Structural stabilization of them followed by intramolecular as well as intermolecular H-bonds makes these molecules as perfect examples in molecular recognition with self-complementary donor and acceptor units within a single molecule. Docking simulations have been performed to position compounds into the FtsZ active site to determine their probable binding model. Compound 3a shows the most potent biological activity, which may be a promising antimicrobial leading compound for the further research.

PROPOSED CARDIAC STEM CELLS DERIVED FROM “CARDIOSPHERES” LACK CARDIOMYOGENIC POTENTIAL

DEFF Research Database (Denmark)

Andersen, Ditte Caroline

   Recent studies have reported that clinical relevant numbers of cardiac stem cells (CSCs) with cardiomyogenic potential can be obtained from small heart tissue biopsies, by an intrinsic ability of CSCs to form beating cardiospheres (CSs) during ex vivo culture. Such data have provided optimism...... that injuried heart tissue may be repaired by stem cell therapy using autologous CS derived cells, and pre-clinical studies have already been described in literature.    Herein, we established CSs from neonatal rats, and by immunofluorescence, qRT-PCR, and microscopic examination we demonstrated...... to form CSs by themselves. Phenotypically, CS cells largely resembled fibroblasts, and they lacked cardiomyogenic as well as endothelial differentiation potential.    Our data imply that at least the murine cardiosphere model seems unsuitable for enrichment of cardiac stem cells with cardiomyogenic...

An accurate method for the determination of unlike potential parameters from thermal diffusion data

International Nuclear Information System (INIS)

El-Geubeily, S.

1997-01-01

A new method is introduced by means of which the unlike intermolecular potential parameters can be determined from the experimental measurements of the thermal diffusion factor as a function of temperature. The method proved to be easy, accurate, and applicable two-, three-, and four-parameter potential functions whose collision integrals are available. The potential parameters computed by this method are found to provide a faith full representation of the thermal diffusion data under consideration. 3 figs., 4 tabs

Mechanism of Intermolecular Electron Transfer in Bionanostructures

Science.gov (United States)

Gruodis, A.; Galikova, N.; Šarka, K.; Saulė, R.; Batiuškaitė, D.; Saulis, G.

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors worldwide. Most patients are inoperable and hepatoma cells are resistant to conventional chemotherapies. Thus, the development of novel therapies for HCC treatment is of paramount importance. Amongst different alimentary factors, vitamin C and vitamin K3 In the present work, it has been shown that the treatment of mouse hepatoma MH-22A cells by vitamin C and vitamin K3 at the ratio of 100:1 greatly enhanced their cytotoxicity. When cells were subjected to vitamin C at 200 μM or to vitamin K3 at 2 μM separately, their viability reduced by only about 10%. However, when vitamins C and K3 were combined at the same concentrations, they killed more than 90% of cells. To elucidate the mechanism of the synergistic cytotoxicity of the C&K3 mixture, theoretical quantum-chemical analysis of the dynamics of intermolecular electron transfer (IET) processes within the complexes containing C (five forms) and K3 (one form) has been carried out. Optimization of the ground state complex geometry has been provided by means of GAUSSIAN03 package. Simulation of the IET has been carried out using NUVOLA package, in the framework of molecular orbitals (MO). The rate of IET has been calculated using Fermi Golden rule. The results of simulations allow us to create the preliminary model of the reaction pathway.

Potential differentiation of islet-like cells from pregnant cow-derived placental stem cells.

Science.gov (United States)

Peng, Shao-Yu; Chou, Chien-Wen; Kuo, Yu-Hsuan; Shen, Perng-Chih; Shaw, S W Steven

2017-06-01

Type 1 diabetes is an autoimmune disease that destroys islet cells and results in insufficient insulin secretion by pancreatic β-cells. Islet transplantation from donors is an approach used for treating patients with diabetes; however, this therapy is difficult to implement because of the lack of donors. Nevertheless, several stem cells have the potential to differentiate from islet-like cells and enable insulin secretion for treating diabetes in animal models. For example, placenta is considered a waste material and can be harvested noninvasively during delivery without ethical or moral concerns. To date, the differentiation of islet-like cells from cow-derived placental stem cells (CPSCs) has yet to be demonstrated. The investigation of potential differentiation of islet-like cells from CPSCs was conducted by supplementation with nicotinamide, exendin-4, glucose, and poly-d-lysine and was detected through reverse transcription polymerase chain reaction, dithizone staining, and immunocytochemical methods. Our results indicated that CPSCs are established and express mesenchymal stem cell surface antigen markers, such as CD73, CD166, β-integrin, and Oct-4, but not hematopoietic stem cell surface antigen markers, such as CD45. After induction, the CPSCs successfully differentiated into islet-like cells. The CPSC-derived islet-like cells expressed islet cell development-related genes, such as insulin, glucagon, pax-4, Nkx6.1, pax-6, and Fox. Moreover, CPSC-derived islet-like cells can be stained with zinc ions, which are widely distributed in the islet cells and enable insulin secretion. Altogether, islet-like cells have the potential to be differentiated from CPSCs without gene manipulation, and can be used in diabetic animal models in the future for preclinical and drug testing trial investigations. Copyright © 2017. Published by Elsevier B.V.

Resolution enhancement in MR spectroscopy of red bone marrow fat via intermolecular double-quantum coherences

Science.gov (United States)

Bao, Jianfeng; Cui, Xiaohong; Huang, Yuqing; Zhong, Jianhui; Chen, Zhong

2015-08-01

High-resolution 1H magnetic resonance spectroscopy (MRS) is generally inaccessible in red bone marrow (RBM) tissues using conventional MRS techniques. This is because signal from these tissues suffers from severe inhomogeneity in the main static B0 field originated from the intrinsic honeycomb structures in trabecular bone. One way to reduce effects of B0 field inhomogeneity is by using the intermolecular double quantum coherence (iDQC) technique, which has been shown in other systems to obtain signals insensitive to B0 field inhomogeneity. In the present study, we employed an iDQC approach to enhance the spectral resolution of RBM. The feasibility and performance of this method for achieving high resolution MRS was verified by experiments on phantoms and pig vertebral bone samples. Unsaturated fatty acid peaks which overlap in the conventional MRS were well resolved and identified in the iDQC spectrum. Quantitative comparison of fractions of three types of fatty acids was performed between iDQC spectra on the in situ RMB and conventional MRS on the extracted fat from the same RBM. Observations of unsaturated fatty acids with iDQC MRS may provide valuable information and may hold potential in diagnosis of diseases such as obesity, diabetes, and leukemia.

Proteome profiling of neuroblastoma-derived exosomes reveal the expression of proteins potentially involved in tumor progression.

Directory of Open Access Journals (Sweden)

Danilo Marimpietri

Full Text Available Neuroblastoma (NB is the most common extracranial solid tumor in childhood, with grim prognosis in a half of patients. Exosomes are nanometer-sized membrane vesicles derived from the multivesicular bodies (MVBs of the endocytic pathway and released by normal and neoplastic cells. Tumor-derived exosomes have been shown in different model systems to carry molecules that promote cancer growth and dissemination. In this respect, we have here performed the first characterization and proteomic analysis of exosomes isolated from human NB cell lines by filtration and ultracentrifugation. Electron microscopy demonstrated that NB-derived exosomes exhibited the characteristic cup-shaped morphology. Dynamic light scattering studies showed a bell-shaped curve and a polydispersity factor consistent with those of exosomes. Zeta potential values suggested a good nanoparticle stability. We performed proteomic analysis of NB-derived exosomes by two dimension liquid chromatography separation and mass spectrometry analyses using the multidimensional protein identification technology strategy. We found that the large majority of the proteins identified in NB derived exosomes are present in Exocarta database including tetraspanins, fibronectin, heat shock proteins, MVB proteins, cytoskeleton-related proteins, prominin-1 (CD133, basigin (CD147 and B7-H3 (CD276. Expression of the CD9, CD63 and CD81 tetraspanins, fibronectin, CD133, CD147 and CD276 was validated by flow cytometry. Noteworthy, flow cytometric analysis showed that NB-derived exosomes expressed the GD2 disialoganglioside, the most specific marker of NB. In conclusion, this study shows that NB-derived exosomes express a discrete set of molecules involved in defense response, cell differentiation, cell proliferation and regulation of other important biological process. Thus, NB-derived exosomes may play an important role in the modulation of tumor microenvironment and represent potential tumor biomarkers.

Constructing high-accuracy intermolecular potential energy surface with multi-dimension Morse/Long-Range model

Science.gov (United States)

Zhai, Yu; Li, Hui; Le Roy, Robert J.

2018-04-01

Spectroscopically accurate Potential Energy Surfaces (PESs) are fundamental for explaining and making predictions of the infrared and microwave spectra of van der Waals (vdW) complexes, and the model used for the potential energy function is critically important for providing accurate, robust and portable analytical PESs. The Morse/Long-Range (MLR) model has proved to be one of the most general, flexible and accurate one-dimensional (1D) model potentials, as it has physically meaningful parameters, is flexible, smooth and differentiable everywhere, to all orders and extrapolates sensibly at both long and short ranges. The Multi-Dimensional Morse/Long-Range (mdMLR) potential energy model described herein is based on that 1D MLR model, and has proved to be effective and accurate in the potentiology of various types of vdW complexes. In this paper, we review the current status of development of the mdMLR model and its application to vdW complexes. The future of the mdMLR model is also discussed. This review can serve as a tutorial for the construction of an mdMLR PES.

Design, Synthesis and Biological Evaluation of Benzohydrazide Derivatives Containing Dihydropyrazoles as Potential EGFR Kinase Inhibitors

Directory of Open Access Journals (Sweden)

Hai-Chao Wang

2016-08-01

Full Text Available A series of novel benzohydrazide derivatives containing dihydropyrazoles have been synthesized as potential epidermal growth factor receptor (EGFR kinase inhibitors and their biological activities as potential antiproliferative agents have been evaluated. Among these compounds, compound H20 exhibited the most potent antiproliferative activity against four cancer cell line variants (A549, MCF-7, HeLa, HepG2 with IC50 values of 0.46, 0.29, 0.15 and 0.21 μM respectively, which showed the most potent EGFR inhibition activities (IC50 = 0.08 μM for EGFR. Molecular modeling simulation studies were performed in order to predict the biological activity and activity relationship (SAR of these benzohydrazide derivatives. These results suggested that compound H20 may be a promising anticancer agent.

Synthesis, crystal structure, Hirshfeld surfaces analysis and anti-ischemic activity of cinnamide derivatives

Science.gov (United States)

Zhong, Jian-gang; Han, Jia-pei; Li, Xiao-feng; Xu, Yi; Zhong, Yan; Wu, Bin

2018-02-01

Two cinnamide derivatives, namely, (E)-1-(4-(bis(4-methylphenyl)- methyl)piperazin-1-yl)-3-(3,4-diethoxyphenyl)prop-2-en-1-one (5) and (E)-1-(4-(bis- (4-fluorophenyl)methyl)piperazin-1-yl)-3-(4-methoxyphenyl)prop-2-en-1-one (6), have been synthesized and characterized by IR spectra, High resolution mass spectra, 1H NMR spectra, 13C NMR spectra. The compound 5 is a novel compound and has never been reported in the literature. Their crystal structures were studied by single-crystal X-ray diffraction. They all crystallize in the monoclinic system. The single-crystal X-ray revealed that compound 5 has infinite X-shaped 1-D polymeric chains structure and compound 6 has a layered 3-D structure by intermolecular interactions. Hirshfeld surface analysis demonstrated the presence of H⋯H, O⋯H, C⋯H, F⋯H, Csbnd H⋯π and π⋯π intermolecular interactions. In addition, the MTT assay results indicated that the compounds 5 and 6 display effective activities against neurotoxicity which is induced by glutamine in PC12 cells. The in vivo experiment indicated that the compound 6 has a good protective effect on cerebral infarction.

Structural characterizations, Hirshfeld surface analyses, and third-order nonlinear optical properties of two novel chalcone derivatives

Science.gov (United States)

Maidur, Shivaraj R.; Jahagirdar, Jitendra R.; Patil, Parutagouda Shankaragouda; Chia, Tze Shyang; Quah, Ching Kheng

2018-01-01

We report synthesis, characterizations, structure-property relationships, and third-order nonlinear optical studies for two new chalcone derivatives, (2E)-1-(anthracen-9-yl)-3-(4-bromophenyl)prop-2-en-1-one (Br-ANC) and (2E)-1-(anthracen-9-yl)-3-(4-chlorophenyl)prop-2-en-1-one (Cl-ANC). These derivatives were crystallized in the centrosymmetric monoclinic P21/c crystal structure. The intermolecular interactions of both the crystals were visualized by Hirshfeld surface analyses (HSA). The crystals are thermally stable up to their melting points (180.82 and 191.16 °C for Cl-ANC and Br-ANC, respectively). The geometry optimizations, FT-IR spectra, 1H and 13C NMR spectra, electronic absorption spectra, electronic transitions, and HOMO-LUMO energy gaps were studied by Density Functional Theory (DFT) at B3LYP/6-311+G(d, p) level. The theoretical results provide excellent agreement with experimental findings. The electric dipole moments, static polarizabilities, molecular electrostatic potentials (MEP) and global chemical reactivity descriptors (GCRD) were also theoretically computed. The materials exhibited good nonlinear absorption (NLA), nonlinear refraction (NLR) and optical limiting (OL) behavior under diode-pumped solid-state (DPSS) continuous wave (CW) laser excitation (532 nm and 200 mW). The NLO parameters such as NLA coefficient (β∼10-5 cmW-1), NLR index (n2∼10-10 cm2 W-1) and third-order NLO susceptibilities (χ(3) ∼10-7 esu) were measured. Further, we estimated one-photon and two-photon figures of merit, which satisfy the demands (W > 1 and T < 1) for all-optical switching. Thus, the present chalcone derivatives with anthracene moiety are potential materials for OL and optical switching applications.

Collision-induced spectroscopy with long-range intermolecular interactions: A diagrammatic representation and the invariant form of the induced properties

International Nuclear Information System (INIS)

Kouzov, A. P.; Chrysos, M.; Rachet, F.; Egorova, N. I.

2006-01-01

Collision-induced properties of two interacting molecules a and b are derived by means of a general diagrammatic method involving M molecule-molecule and N photon-molecule couplings. The method is an extension of previous graphical treatments of nonlinear optics because it exhaustively determines interaction-induced polarization mechanisms in a trustworthy and handy fashion. Here we focus on long-range intermolecular interactions. Retardation effects are neglected. A fully quantum-mechanical treatment of the molecules is made whereas second quantization for the electromagnetic field, in the nonrelativistic approximation, is implicitly applied. The collision-induced absorption, Raman, and hyper-Raman processes are viewed and studied, through guiding examples, as specific cases N=1, 2, and 3, respectively. In Raman (N=2), the standard first-order (M=1) dipole-induced dipole term of the incremental polarizability, Δα, is the result of a coupling of the two photons with distinct molecules, a and b, which perturb each other via a dipole-dipole mechanism. Rather, when the two photons interact with the same molecule, a or b, the (N=2, M=1) graphs predict the occurrence of a nonlinear polarization mechanism. The latter is expected to contribute substantially to the collision-induced Raman bands by certain molecular gases

Monte Carlo study of one-dimensional confined fluids with Gay-Berne intermolecular potential

Science.gov (United States)

Moradi, M.; Hashemi, S.

2011-11-01

The thermodynamic quantities of a one dimensional system of particles with Gay-Berne model potential confined between walls have been obtained by means of Monte Carlo computer simulations. For a number of temperatures, the systems were considered and their density profiles, order parameter, pressure, configurational temperature and average potential energy per particle are reported. The results show that by decreasing the temperature, the soft particles become more ordered and they align to the walls and also they don't show any tendency to be near the walls at very low temperatures. We have also changed the structure of the walls by embedding soft ellipses in them, this change increases the total density near the wall whereas, increasing or decreasing the order parameter depend on the angle of embedded ellipses.

Structure-based design of nitrosoureas containing tyrosine derivatives as potential antimelanoma agents.

Science.gov (United States)

Gadjeva, Vesselina

2002-04-01

Two new nitrosoureas (TNUs), containing tyrosine derivatives as carriers of nitrosourea cytotoxic group have been synthesised. The physicochemical properties such as half-life time (tau(0.5)), alkylating and carbamoylating activities were determined. The nitrosoureas showed a higher inhibiting effect on the DOPA-oxidase activity of mushroom tyrosinase than that of the antitumour drug N'-cyclohexyl-N-(2-chloroethyl)-N-nitrosourea (lomustine, CCNU). In vitro cytotoxic effects of newly synthesised tyrosine containing nitrosoureas have been studied and compared to those of CCNU. A higher cytotoxicity to B16 melanoma cells than to YAC-1 and to lymphocytes was demonstrated for the tyrosine containing nitrosoureas in comparison with CCNU. Based on the results presented, we accept that a new trend for synthesis of more selective and less toxic nitrosourea derivatives as potential antimelanomic drugs might be developed.

The role of pancreatic cancer-derived exosomes in cancer progress and their potential application as biomarkers.

Science.gov (United States)

Jin, H; Wu, Y; Tan, X

2017-08-01

Pancreatic cancer is one of the most deadly cancers, with dismal prognosis due to its poor early detection rate and high metastatic rate. Thus, elucidation of the molecular mechanisms accounting for its metastasis and discovery of competent biomarkers is required. Exosomes are multivesicular body-derived small extracellular vesicles released by various cell types that serve as important message carriers during intercellular communication. They are also known to play critical roles during cancer-genesis, cancer-related immune reactions, and metastasis. They also possess promising potential as novel biomarkers for cancer early detection. Therefore, extensive studies on pancreatic cancer-derived exosomes are currently being performed because they hold the promising potential of elevating the overall survival rate of patients with pancreatic cancer. In the present review, we focus on the role of exosomes in pancreatic cancer-related immune reactions, metastasis, and complications, and on their potential application as pancreatic cancer biomarkers.

Resonance Raman spectra of organic molecules absorbed on inorganic semiconducting surfaces: Contribution from both localized intramolecular excitation and intermolecular charge transfer excitation

International Nuclear Information System (INIS)

Ye, ChuanXiang; Zhao, Yi; Liang, WanZhen

2015-01-01

The time-dependent correlation function approach for the calculations of absorption and resonance Raman spectra (RRS) of organic molecules absorbed on semiconductor surfaces [Y. Zhao and W. Z. Liang, J. Chem. Phys. 135, 044108 (2011)] is extended to include the contribution of the intermolecular charge transfer (CT) excitation from the absorbers to the semiconducting nanoparticles. The results demonstrate that the bidirectionally interfacial CT significantly modifies the spectral line shapes. Although the intermolecular CT excitation makes the absorption spectra red shift slightly, it essentially changes the relative intensities of mode-specific RRS and causes the oscillation behavior of surface enhanced Raman spectra with respect to interfacial electronic couplings. Furthermore, the constructive and destructive interferences of RRS from the localized molecular excitation and CT excitation are observed with respect to the electronic coupling and the bottom position of conductor band. The interferences are determined by both excitation pathways and bidirectionally interfacial CT

Refuse derived fuel potential in DKI Jakarta

Science.gov (United States)

Widyatmoko, H.

2018-01-01

Combustible waste fractions of municipal solid waste (MSW) which can not be easily separated or sorted, reused or recycled, may have a high calorifiv value (CV) that can be used in a fuel for energy recovery. The objective of this study was to explore the Refuse Derived Fuel (RDF) potential of municipal solid waste from DKI Jakarta to produce electricity and to promote it to be socially and politically acceptable. For this purpose, 24 sampels of RDF were taken from Bantargebang, cabonized, molded and pressed to be briquette. All samples were analized for moisture, ash, and calorific value in the physical and chemistry Laboratory of ITB Bandung. The analysis of calorific value (CV) shows the CV difference of 1815.8 cal/g between the briquettes (8051.25 cal/g) and the RDF (9867.12 cal/g. The total waste DKI which can be used as briquettes 5253 ton / day or equivalent with 49154115 kWh / day. If the efficiency of electricity production from RDF was 25%, then Jakarta is able to generate electricity from RDF of 12288529 kWh / day or as much as energy needed by 573,480 middle-class households with energy needs of 642.84 kWh/month.

CORONAL MAGNETIC FIELDS DERIVED FROM SIMULTANEOUS MICROWAVE AND EUV OBSERVATIONS AND COMPARISON WITH THE POTENTIAL FIELD MODEL

Energy Technology Data Exchange (ETDEWEB)

Miyawaki, Shun; Nozawa, Satoshi [Department of Science, Ibaraki University, Mito, Ibaraki 310-8512 (Japan); Iwai, Kazumasa; Shibasaki, Kiyoto [Nobeyama Solar Radio Observatory, National Astronomical Observatory of Japan, Minamimaki, Nagano 384-1305 (Japan); Shiota, Daikou, E-mail: shunmi089@gmail.com [Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya, Aichi 464-8601 (Japan)

2016-02-10

We estimated the accuracy of coronal magnetic fields derived from radio observations by comparing them to potential field calculations and the differential emission measure measurements using EUV observations. We derived line-of-sight components of the coronal magnetic field from polarization observations of the thermal bremsstrahlung in the NOAA active region 11150, observed around 3:00 UT on 2011 February 3 using the Nobeyama Radioheliograph at 17 GHz. Because the thermal bremsstrahlung intensity at 17 GHz includes both chromospheric and coronal components, we extracted only the coronal component by measuring the coronal emission measure in EUV observations. In addition, we derived only the radio polarization component of the corona by selecting the region of coronal loops and weak magnetic field strength in the chromosphere along the line of sight. The upper limits of the coronal longitudinal magnetic fields were determined as 100–210 G. We also calculated the coronal longitudinal magnetic fields from the potential field extrapolation using the photospheric magnetic field obtained from the Helioseismic and Magnetic Imager. However, the calculated potential fields were certainly smaller than the observed coronal longitudinal magnetic field. This discrepancy between the potential and the observed magnetic field strengths can be explained consistently by two reasons: (1) the underestimation of the coronal emission measure resulting from the limitation of the temperature range of the EUV observations, and (2) the underestimation of the coronal magnetic field resulting from the potential field assumption.

Measuring Intermolecular Binding Energies by Laser Spectroscopy.

Science.gov (United States)

Knochenmuss, Richard; Maity, Surajit; Féraud, Géraldine; Leutwyler, Samuel

2017-02-22

The ground-state dissociation energy, D0(S0), of isolated intermolecular complexes in the gas phase is a fundamental measure of the interaction strength between the molecules. We have developed a three-laser, triply resonant pump-dump-probe technique to measure dissociation energies of jet-cooled M•S complexes, where M is an aromatic chromophore and S is a closed-shell 'solvent' molecule. Stimulated emission pumping (SEP) via the S0→S1 electronic transition is used to precisely 'warm' the complex by populating high vibrational levels v" of the S0 state. If the deposited energy E(v") is less than D0(S0), the complex remains intact, and is then mass- and isomer-selectively detected by resonant two-photon ionization (R2PI) with a third (probe) laser. If the pumped level is above D0(S0), the hot complex dissociates and the probe signal disappears. Combining the fluorescence or SEP spectrum of the cold complex with the SEP breakoff of the hot complex brackets D0(S0). The UV chromophores 1-naphthol and carbazole were employed; these bind either dispersively via the aromatic rings, or form a hydrogen bond via the -OH or -NH group. Dissociation energies have been measured for dispersively bound complexes with noble gases (Ne, Kr, Ar, Xe), diatomics (N2, CO), alkanes (methane to n-butane), cycloalkanes (cyclopropane to cycloheptane), and unsaturated compounds (ethene, benzene). Hydrogen-bond dissociation energies have been measured for H2O, D2O, methanol, ethanol, ethers (oxirane, oxetane), NH3 and ND3.

Hamiltonian and potentials in derivative pricing models: exact results and lattice simulations

Science.gov (United States)

Baaquie, Belal E.; Corianò, Claudio; Srikant, Marakani

2004-03-01

The pricing of options, warrants and other derivative securities is one of the great success of financial economics. These financial products can be modeled and simulated using quantum mechanical instruments based on a Hamiltonian formulation. We show here some applications of these methods for various potentials, which we have simulated via lattice Langevin and Monte Carlo algorithms, to the pricing of options. We focus on barrier or path dependent options, showing in some detail the computational strategies involved.

Current knowledge on agarolytic enzymes and the industrial potential of agar-derived sugars.

Science.gov (United States)

Yun, Eun Ju; Yu, Sora; Kim, Kyoung Heon

2017-07-01

Agar is a major cell wall carbohydrate of red macroalgae (Rhodophyta). Sugars derived from agar, such as agarooligosaccharides (AOSs), neoagarooligosaccharides (NAOSs), neoagarobiose (NAB), and 3,6-anhydro-L-galactose (L-AHG), possess various physiological activities. These agar-derived sugars can be produced by hydrolysis using chemicals or agarolytic enzymes. Despite the industrial potential of agar-derived sugars, their application has been hampered mainly due to the absence of efficient processes for the liquefaction and saccharification of agar. In this review, we have focused on strategies for producing high value-added sugars from agarose via chemical or enzymatic liquefaction and enzymatic saccharification. The liquefaction of agarose is a key step for preventing gelling and increasing the solubility of agarose in water by prehydrolyzing agarose into AOSs or NAOSs. For the industrial use of agar-derived sugars, AOS, NAOS, NAB, and L-AHG can be used as functional biomaterials owing to their physiological activities such as antiinflammation, skin whitening, and moisturizing. Recently, it was reported that AHG could be considered as a new anticariogenic sugar to replace xylitol. This review provides a comprehensive overview of processes for the hydrolysis of agar or agarose to produce high value-added sugars and the industrial application of these sugars.

Intermolecular potential for Ar + D2O from differential scattering cross sections, and its implications for the water pair potential

International Nuclear Information System (INIS)

Brooks, R.; Porter, R.A.R.; Kalos, F.; Grosser, A.E.

1975-01-01

A velocity selected molecular beam of D 2 O was crossed with a nozzle beam of Ar and the angular distribution of the scattered D 2 O was measured mass spectrometrically. By varying the velocity of the D 2 O beam, the differential cross section was measured at two collision energies. The experimental results were compared with synthetic differential cross sections calculated from Lennard-Jones and Kihara-Stockmayer trial potentials to determine potential parameters. Implications for the H 2 O pair potential are discussed

Intermolecular interactions of decamethoxinum and acetylsalicylic acid in systems of various complexity levels

Directory of Open Access Journals (Sweden)

O. V. Vashchenko

2016-07-01

Full Text Available Intermolecular interactions between decamethoxinum (DEC and acetylsalicylic acid (ASА have been studied in the phospholipid-containing systems of escalating complexity levels. The host media for these substances were solvents, L-α-dipalmitoylphosphatidylcholine (DPPC membranes, and samples of human erythrocytes. Peculiar effects caused by DEC-ASА interaction have been observed in each system using appropriate techniques: (a DEC-ASА non-covalent complexes formation in DPPC-containing systems were revealed by mass spectrometry with electrospray ionization; (b joint DEC-ASА action on DPPC model membranes led to increasing of membrane melting temperature Tm, whereas individual drugs caused pronounced Tm decreasing, which was demonstrated by differential scanning calorimetry; (c deceleration of DEC-induced haemolysis of erythrocytes under joint DEC-ASА application was observed by optical microscopy.

Conformation of an Shc-derived phosphotyrosine-containing peptide complexed with the Grb2 SH2 domain

International Nuclear Information System (INIS)

Ogura, Kenji; Tsuchiya, Shigeo; Terasawa, Hiroaki; Yuzawa, Satoru; Hatanaka, Hideki; Mandiyan, Valsan; Schlessinger, Joseph; Inagaki, Fuyuhiko

1997-01-01

We have determined the structure of an Shc-derived phosphotyrosine-containing peptide complexed with Grb2 SH2 based on intra-and intermolecular NOE correlations observed by a series of isotope-filtered NMR experiments using a PFG z-filter. In contrast to an extended conformation of phosphotyrosine-containing peptides bound to Src, Syp and PLC γ SH2s, the Shc-derived peptide formed a turn at the +1 and +2 positions next to the phosphotyrosine residue. Trp 121 , located at the EF1 site of Grb2 SH2, blocked the peptide binding in an extended conformation. The present study confirms that each phosphotyrosine-containing peptide binds to the cognate SH2 with a specific conformation, which gives the structural basis for the binding specificity between SH2s and target proteins

Novel NSAID-Derived Drugs for the Potential Treatment of Alzheimer’s Disease

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Ivana Cacciatore

2016-06-01

Full Text Available Nonsteroidal anti-inflammatory drugs (NSAIDs have been suggested for the potential treatment of neurodegenerative diseases, such as Alzheimer’s disease (AD. Prolonged use of NSAIDs, however, produces gastrointestinal (GI toxicity. To overcome this serious limitation, the aim of this study was to develop novel NSAID-derived drug conjugates (Anti-inflammatory-Lipoyl derivatives, AL4–9 that preserve the beneficial effects of NSAIDS without causing GI problems. As such, we conjugated selected well-known NSAIDs, such as (S-naproxen and (R-flurbiprofen, with (R-α-lipoic acid (LA through alkylene diamine linkers. The selection of the antioxidant LA was based on the proposed role of oxidative stress in the development and/or progression of AD. Our exploratory studies revealed that AL7 containing the diaminoethylene linker between (R-flurbiprofen and LA had the most favorable chemical and in vitro enzymatic stability profiles among the synthesized compounds. Upon pretreatment, this compound exhibited excellent antioxidant activity in phorbol 12-miristate 13-acetate (PMA-stimulated U937 cells (lymphoblast lung from human and Aβ(25–35-treated THP-1 cells (leukemic monocytes. Furthermore, AL7 also modulated the expression of COX-2, IL-1β and TNF-α in these cell lines, suggesting anti-inflammatory activity. Taken together, AL7 has emerged as a potential lead worthy of further characterization and testing in suitable in vivo models of AD.

Chain-length-dependent intermolecular packing in polyphenylenes: a high pressure study

CERN Document Server

Heimel, G; Oehzelt, M; Hummer, K; Koppelhuber-Bitschnau, B; Porsch, F; Ambrosch-Draxl, C; Resel, R

2003-01-01

We report on pressure-induced structural changes in crystalline oligo(para-phenylenes) containing two to six phenyl rings. The results are discussed with particular emphasis put on the implications these changes in intermolecular distances and molecular arrangement have on important bulk properties of this class of materials, such as optical response and charge transport. We performed energy dispersive x-ray diffraction in a systematic study on polycrystalline powders of biphenyl, para-terphenyl, p-quaterphenyl, p-quinquephenyl and p-sexiphenyl under hydrostatic pressure up to 60 kbar. Revisiting the crystal structures at ambient conditions reveals details in the packing principle. A linear relationship between the density at ambient conditions and the number of phenyl rings is found. High pressure data not only yields pressure-dependent lattice parameters and hints towards pressure-induced changes in the molecular arrangement but also allows for an analysis of the equations of state of these substances as a ...

Empirical temperature-dependent intermolecular potentials determined by data mining from crystal data

Science.gov (United States)

Hofmann, D. W. M.; Kuleshova, L. N.

2018-05-01

Modern force fields are accurate enough to describe thermal effects in molecular crystals. Here, we have extended our earlier approach to discrete force fields for various temperatures to a force field with a continuous function. For the parametrisation of the force field, we used data mining on experimental structures with the temperature as an additional descriptor. The obtained force field can be used to minimise energy at a finite temperature and for molecular dynamics with zero-K potentials. The applicability of the method has been demonstrated for the prediction of crystal density, temperature density gradients and transition temperature.

Epipolythiodiketopiperazines from the Marine Derived Fungus Dichotomomyces cejpii with NF-κB Inhibitory Potential

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Henrik Harms

2015-08-01

Full Text Available The Ascomycota Dichotomomyces cejpii was isolated from the marine sponge Callyspongia cf. C. flammea. A new gliotoxin derivative, 6-acetylmonodethiogliotoxin (1 was obtained from fungal extracts. Compounds 2 and 3, methylthio-gliotoxin derivatives were formerly only known as semi-synthetic compounds and are here described as natural products. Additionally the polyketide heveadride (4 was isolated. Compounds 1, 2 and 4 dose-dependently down-regulated TNFα-induced NF-κB activity in human chronic myeloid leukemia cells with IC50s of 38.5 ± 1.2 µM, 65.7 ± 2.0 µM and 82.7 ± 11.3 µM, respectively. The molecular mechanism was studied with the most potent compound 1 and results indicate downstream inhibitory effects targeting binding of NF-κB to DNA. Compound 1 thus demonstrates potential of epimonothiodiketopiperazine-derived compounds for the development of NF-κB inhibitors.

Chemical cross-linking with thiol-cleavable reagents combined with differential mass spectrometric peptide mapping--a novel approach to assess intermolecular protein contacts

DEFF Research Database (Denmark)

Bennett, K L; Kussmann, M; Björk, P

2000-01-01

The intermolecular contact regions between monomers of the homodimeric DNA binding protein ParR and the interaction between the glycoproteins CD28 and CD80 were investigated using a strategy that combined chemical cross-linking with differential MALDI-MS analyses. ParR dimers were modified in vit...

Bone Marrow Stem Cell Derived Paracrine Factors for Regenerative Medicine: Current Perspectives and Therapeutic Potential

Directory of Open Access Journals (Sweden)

Tom J. Burdon

2011-01-01

Full Text Available During the past several years, there has been intense research in the field of bone marrow-derived stem cell (BMSC therapy to facilitate its translation into clinical setting. Although a lot has been accomplished, plenty of challenges lie ahead. Furthermore, there is a growing body of evidence showing that administration of BMSC-derived conditioned media (BMSC-CM can recapitulate the beneficial effects observed after stem cell therapy. BMSCs produce a wide range of cytokines and chemokines that have, until now, shown extensive therapeutic potential. These paracrine mechanisms could be as diverse as stimulating receptor-mediated survival pathways, inducing stem cell homing and differentiation or regulating the anti-inflammatory effects in wounded areas. The current review reflects the rapid shift of interest from BMSC to BMSC-CM to alleviate many logistical and technical issues regarding cell therapy and evaluates its future potential as an effective regenerative therapy.

Synthesis of an estradiol glucuronide derivative and investigation of its radiopharmaceutical potential

International Nuclear Information System (INIS)

Biber, F.Z.; Unak, P.; Ertay, T.; Medine, E.I.; Zihnioglu, F.; Tasci, C.; Durak, H.

2006-01-01

The aim of the current study was to synthesize a derivative of estradiol glucuronide, which is able to be labeled with 99m Tc and to investigate its radiopharmaceutical potential using imaging and biodistribution studies. An estrogen derivative, β-estradiol (1,3,5,[10]-estratriene-3,17β-diol) attached to diethylenetriamine pentaacetic acid (DTPA) was synthesized in six steps. At the end of these steps a compound of estradiol and DTPA derivative called deoxy demethyl homoestradiolyl diethylenetriamine pentaacetic acid (ESTDTPA) was synthesized. Afterwards, this compound was reacted with UDP-glucuronyl transferase (UDPGT). Following the glucuronidation reaction, the product called deoxy demethyl homoestradiolyl diethylenetriamine pentaaceticacid-glucuronide (ESTDTPAG) was obtained. Synthesized products were purified using high performance liquid chromatography (HPLC). The identification of the purified products and impurities were also established using HPLC. Synthesized compound was labeled with 99m Tc. Thin layer radio chromatography (TLRC) technique was used to determine their radiochemical yields and stabilities. Labeling yield was over 96%. The biodistribution studies were performed on female Albino Wistar rats. The activity per gram tissue was calculated and time-activity curves were plotted. The target organs (tumor, as well as uterus, ovaries, adrenals and other ER containing tissues) retain the estradiol derivative longer than nontarget organs, but even these lost most of their activity within a few hours. In addition, the imaging studies were performed on normal and tumor bearing female Albino Wistar rats using Camstar XR/T gamma camera. In γ-scintigraphic imaging studies with 99m Tc-ESTDTPAG the breast tumors could be well visualized up to 24 h

Isoprene emission potentials from European oak forests derived from canopy flux measurements: an assessment of uncertainties and inter-algorithm variability

Science.gov (United States)

Langford, Ben; Cash, James; Acton, W. Joe F.; Valach, Amy C.; Hewitt, C. Nicholas; Fares, Silvano; Goded, Ignacio; Gruening, Carsten; House, Emily; Kalogridis, Athina-Cerise; Gros, Valérie; Schafers, Richard; Thomas, Rick; Broadmeadow, Mark; Nemitz, Eiko

2017-12-01

Biogenic emission algorithms predict that oak forests account for ˜ 70 % of the total European isoprene budget. Yet the isoprene emission potentials (IEPs) that underpin these model estimates are calculated from a very limited number of leaf-level observations and hence are highly uncertain. Increasingly, micrometeorological techniques such as eddy covariance are used to measure whole-canopy fluxes directly, from which isoprene emission potentials can be calculated. Here, we review five observational datasets of isoprene fluxes from a range of oak forests in the UK, Italy and France. We outline procedures to correct the measured net fluxes for losses from deposition and chemical flux divergence, which were found to be on the order of 5-8 and 4-5 %, respectively. The corrected observational data were used to derive isoprene emission potentials at each site in a two-step process. Firstly, six commonly used emission algorithms were inverted to back out time series of isoprene emission potential, and then an average isoprene emission potential was calculated for each site with an associated uncertainty. We used these data to assess how the derived emission potentials change depending upon the specific emission algorithm used and, importantly, on the particular approach adopted to derive an average site-specific emission potential. Our results show that isoprene emission potentials can vary by up to a factor of 4 depending on the specific algorithm used and whether or not it is used in a big-leaf or canopy environment (CE) model format. When using the same algorithm, the calculated average isoprene emission potential was found to vary by as much as 34 % depending on how the average was derived. Using a consistent approach with version 2.1 of the Model for Emissions of Gases and Aerosols from Nature (MEGAN), we derive new ecosystem-scale isoprene emission potentials for the five measurement sites: Alice Holt, UK (10 500 ± 2500 µg m-2 h-1); Bosco Fontana, Italy (1610 �

Identification of intra- and intermolecular disulfide bridges in the multidrug resistance transporter ABCG2

DEFF Research Database (Denmark)

Henriksen, Ulla Birk; Fog, Jacob U; Litman, Thomas

2005-01-01

cysteines predicted to be on the extracellular face of ABCG2. Upon mutation of Cys-592 or Cys-608 to alanine (C592A and C608A), ABCG2 migrated as a dimer in SDS-PAGE under non-reducing conditions; however, mutation of Cys-603 to Ala (C603A) caused the transporter to migrate as a single monomeric band....... Despite this change, C603A displayed efficient membrane targeting and preserved transport function. Because the transporter migrated as a dimer in SDS-PAGE, when only Cys-603 was present (C592A-C608A), the data suggest that Cys-603 forms a symmetrical intermolecular disulfide bridge in the ABCG2 homodimer...

Kinetics of isotope exchange reactions involving intra- and intermolecular reactions: 1. Rate law for a system with two chemical compounds and three exchangeable atoms

International Nuclear Information System (INIS)

Xuelei Chu; Ohmoto, Hiroshi

1991-01-01

For an isotopic exchange reaction between two compounds (X and AB) in a homogeneous system, such as a gaseous or aqueous system, where one (AB) of them possesses two exchangeable atoms in non-equivalent positions and where one intramolecular isotope exchange (A ↔ B) and two intermolecular isotope exchange reactions (X ↔ A and X ↔ B) may occur, its rate law no longer obeys a pseudo-first order rate equation described for simple two-component systems by many previous investigators. The change with time of the δ value of each of the three components (X, A, and B) in a closed and homogeneous system is a complicated function of the initial δ values of the three components, the chemical concentrations of the two compounds, and the overall rate constants of the forward and reverse reactions involving the two intermolecular and one intramolecular reactions of isotope exchanges. Also, for some one of the three components, the change of its δ value with time may not be monotonic, and the relationship of 1n (1 - F) with time may be non-linear in a plot of 1n (1 - F) vs. t. In addition, the rate law of the isotope exchange reaction in this system also provides a quantitative method to estimate the overall rate constants for the one-intra-and two intermolecular isotope exchanges and the equilibrium isotopic fractionation factors among the three components

Chondrogenic potential of mesenchymal stromal cells derived from equine bone marrow and umbilical cord blood

DEFF Research Database (Denmark)

Berg, Lise Charlotte; Koch, Thomas Gadegaard; Heerkens, T.

2009-01-01

Objective: Orthopaedic injury is the most common cause of lost training days or premature retirement in the equine athlete. Cell-based therapies are a potential new treatment option in musculo-skeletal diseases. Mesenthymal stromal cells (MSC) have been derived from multiple sources in the horse...

Substituent effects on the electronic characteristics of pentacene derivatives for organic electronic devices: dioxolane-substituted pentacene derivatives with triisopropylsilylethynyl functional groups.

Science.gov (United States)

Griffith, Olga Lobanova; Anthony, John E; Jones, Adolphus G; Shu, Ying; Lichtenberger, Dennis L

2012-08-29

The intramolecular electronic structures and intermolecular electronic interactions of 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS pentacene), 6,14-bis-(triisopropylsilylethynyl)-1,3,9,11-tetraoxa-dicyclopenta[b,m]-pentacene (TP-5 pentacene), and 2,2,10,10-tetraethyl-6,14-bis-(triisopropylsilylethynyl)-1,3,9,11-tetraoxa-dicyclopenta[b,m]pentacene (EtTP-5 pentacene) have been investigated by the combination of gas-phase and solid-phase photoelectron spectroscopy measurements. Further insight has been provided by electrochemical measurements in solution, and the principles that emerge are supported by electronic structure calculations. The measurements show that the energies of electron transfer such as the reorganization energies, ionization energies, charge-injection barriers, polarization energies, and HOMO-LUMO energy gaps are strongly dependent on the particular functionalization of the pentacene core. The ionization energy trends as a function of the substitution observed for molecules in the gas phase are not reproduced in measurements of the molecules in the condensed phase due to polarization effects in the solid. The electronic behavior of these materials is impacted less by the direct substituent electronic effects on the individual molecules than by the indirect consequences of substituent effects on the intermolecular interactions. The ionization energies as a function of film thickness give information on the relative electrical conductivity of the films, and all three molecules show different material behavior. The stronger intermolecular interactions in TP-5 pentacene films lead to better charge transfer properties versus those in TIPS pentacene films, and EtTP-5 pentacene films have very weak intermolecular interactions and the poorest charge transfer properties of these molecules.

Induced pluripotent stem cells (iPSCs) derived from different cell sources and their potential for regenerative and personalized medicine.

Science.gov (United States)

Shtrichman, R; Germanguz, I; Itskovitz-Eldor, J

2013-06-01

Human induced pluripotent stem cells (hiPSCs) have great potential as a robust source of progenitors for regenerative medicine. The novel technology also enables the derivation of patient-specific cells for applications to personalized medicine, such as for personal drug screening and toxicology. However, the biological characteristics of iPSCs are not yet fully understood and their similarity to human embryonic stem cells (hESCs) is still unresolved. Variations among iPSCs, resulting from their original tissue or cell source, and from the experimental protocols used for their derivation, significantly affect epigenetic properties and differentiation potential. Here we review the potential of iPSCs for regenerative and personalized medicine, and assess their expression pattern, epigenetic memory and differentiation capabilities in relation to their parental tissue source. We also summarize the patient-specific iPSCs that have been derived for applications in biological research and drug discovery; and review risks that must be overcome in order to use iPSC technology for clinical applications.

Neutron vibrational spectroscopic studies of novel tire-derived carbon materials.

Science.gov (United States)

Li, Yunchao; Cheng, Yongqiang; Daemen, Luke L; Veith, Gabriel M; Levine, Alan M; Lee, Richard J; Mahurin, Shannon M; Dai, Sheng; Naskar, Amit K; Paranthaman, Mariappan Parans

2017-08-23

Sulfonated tire-derived carbons have been demonstrated to be high value-added carbon products of tire recycling in several energy storage system applications including lithium, sodium, potassium ion batteries and supercapacitors. In this communication, we compared different temperature pyrolyzed sulfonated tire-derived carbons with commercial graphite and unmodified/non-functionalized tire-derived carbon by studying the surface chemistry and properties, vibrational spectroscopy of the molecular structure, chemical bonding such as C-H bonding, and intermolecular interactions of the carbon materials. The nitrogen adsorption-desorption studies revealed the tailored micro and meso pore size distribution of the carbon during the sulfonation process. XPS and neutron vibrational spectra showed that the sulfonation of the initial raw tire powders could remove the aliphatic hydrogen containing groups ([double bond splayed left]CH 2 and -CH 3 groups) and reduce the number of heteroatoms that connect to carbon. The absence of these functional groups could effectively improve the first cycle efficiency of the material in rechargeable batteries. Meanwhile, the introduced -SO 3 H functional group helped in producing terminal H at the edge of the sp 2 bonded graphite-like layers. This study reveals the influence of the sulfonation process on the recovered hard carbon from used tires and provides a pathway to develop and improve advanced energy storage materials.

Intermolecular potential energy surface and thermophysical properties of the CH4-N2 system.

Science.gov (United States)

Hellmann, Robert; Bich, Eckard; Vogel, Eckhard; Vesovic, Velisa

2014-12-14

A five-dimensional potential energy surface (PES) for the interaction of a rigid methane molecule with a rigid nitrogen molecule was determined from quantum-chemical ab initio calculations. The counterpoise-corrected supermolecular approach at the CCSD(T) level of theory was utilized to compute a total of 743 points on the PES. The interaction energies were calculated using basis sets of up to quadruple-zeta quality with bond functions and were extrapolated to the complete basis set limit. An analytical site-site potential function with nine sites for methane and five sites for nitrogen was fitted to the interaction energies. The PES was validated by calculating the cross second virial coefficient as well as the shear viscosity and binary diffusion coefficient in the dilute-gas limit for CH4-N2 mixtures. An improved PES was obtained by adjusting a single parameter of the analytical potential function in such a way that quantitative agreement with the most accurate experimental values of the cross second virial coefficient was achieved. The transport property values obtained with the adjusted PES are in good agreement with the best experimental data.

A Closer Look at Trends in Boiling Points of Hydrides: Using an Inquiry-Based Approach to Teach Intermolecular Forces of Attraction

Science.gov (United States)

Glazier, Samantha; Marano, Nadia; Eisen, Laura

2010-01-01

We describe how we use boiling-point trends of group IV-VII hydrides to introduce intermolecular forces in our first-year general chemistry classes. Starting with the idea that molecules in the liquid state are held together by some kind of force that must be overcome for boiling to take place, students use data analysis and critical reasoning to…

A thiourea derivative as potential ionophore for copper sensing

Science.gov (United States)

Ying, Kook Shih; Heng, Lee Yook; Hassan, Nurul Izzaty; Hasbullah, Siti Aishah

2018-04-01

A new thiourea derivative, N1,N3-bis[[3,5-bis(trifluoromethyl)phenyl]carbamothioyl]isophthalamide (TPC), as a potential copper ionophore was investigated. TPC was immobilized via drop casting method into poly(n-butyl acrylate) pBA membrane and the sensor was characterized by potentiometric method. The sensor fabricated based on TPC showed a Nernstian response towards copper ion with the slope of 27.07±2.84 mV/decade in the range of 1.0×10-6 - 1.0-10-4 M and limit of detection of 6.24 × 10-7 M. In addition, based on the separate solution method (SSM), the logarithm selectivity coefficients were less than -3.00 for monovalent, divalent and trivalent cations that are present in the environmental water samples such as K+, Ca2+, Mg2+ and Fe3+. This confirmed that the sensor fabricated with TPC exhibited good sensitivity and selectivity towards copper ion.

In vitro cardiomyogenic potential of human umbilical vein-derived mesenchymal stem cells

International Nuclear Information System (INIS)

Kadivar, Mehdi; Khatami, Shohreh; Mortazavi, Yousef; Shokrgozar, Mohammad Ali; Taghikhani, Mohammad; Soleimani, Masoud

2006-01-01

Cardiomyocyte loss in the ischemically injured human heart often leads to irreversible defects in cardiac function. Recently, cellular cardiomyoplasty with mesenchymal stem cells, which are multipotent cells with the ability to differentiate into specialized cells under appropriate stimuli, has emerged as a new approach for repairing damaged myocardium. In the present study, the potential of human umbilical cord-derived mesenchymal stem cells to differentiate into cells with characteristics of cardiomyocyte was investigated. Mesenchymal stem cells were isolated from endothelial/subendothelial layers of the human umbilical cords using a method similar to that of human umbilical vein endothelial cell isolation. Isolated cells were characterized by transdifferentiation ability to adipocytes and osteoblasts, and also with flow cytometry analysis. After treatment with 5-azacytidine, the human umbilical cord-derived mesenchymal stem cells were morphologically transformed into cardiomyocyte-like cells and expressed cardiac differentiation markers. During the differentiation, cells were monitored by a phase contrast microscope and their morphological changes were demonstrated. Immunostaining of the differentiated cells for sarcomeric myosin (MF20), desmin, cardiac troponin I, and sarcomeric α-actinin was positive. RT-PCR analysis showed that these differentiated cells express cardiac-specific genes. Transmission electron microscopy revealed a cardiomyocyte-like ultrastructure and typical sarcomers. These observations confirm that human umbilical cord-derived mesenchymal stem cells can be chemically transformed into cardiomyocytes and can be considered as a source of cells for cellular cardiomyoplasty

In vitro phototoxic potential and photochemical properties of imidazopyridine derivative: a novel 5-HT4 partial agonist.

Science.gov (United States)

Onoue, Satomi; Igarashi, Naoko; Yamauchi, Yukinori; Kojima, Takashi; Murase, Noriaki; Zhou, Yu; Yamada, Shizuo; Tsuda, Yoshiko

2008-10-01

Drug-induced phototoxic skin responses have been recognized as undesirable side effects, and as we previously proposed the determination of reactive oxygen species (ROS) from photo-irradiated compounds can be effective for the prediction of phototoxic potential. In this investigation, we evaluated the photosensitizing properties of imidazopyridine derivative, a novel 5-HT(4) partial agonist, using ROS assay and several analytical/biochemical techniques. Exposure of the compound to simulated sunlight resulted in the significant production of singlet oxygen, which is indicative of its phototoxic potential. In practice, an imidazopyridine derivative under UVA/B light exposure also showed significant photodegradation and even photobiochemical events; peroxidation of fatty acid and genetic damage after DNA-binding, which are considered as causative agents for phototoxic dermatitis. Interestingly, both photodegradation and lipoperoxidation were dramatically attenuated by the addition of radical scavengers, especially singlet oxygen quenchers, suggesting the possible involvement of ROS generation in the phototoxic pathways. In the 3T3 neutral red uptake phototoxicity test, imidazopyridine derivative also showed the phototoxic effect on 3T3 mouse fibroblast cells. These results suggest the phototoxic risk of newly synthesized imidazopyridine derivative and also verify the usefulness of ROS assay for phototoxicity prediction. (c) 2008 Wiley-Liss, Inc. and the American Pharmacists Association

Explicit correlation treatment of the potential energy surface of CO{sub 2} dimer

Energy Technology Data Exchange (ETDEWEB)

Kalugina, Yulia N., E-mail: kalugina@phys.tsu.ru [Tomsk State University, 36 Lenin Ave., Tomsk 634050 (Russian Federation); Buryak, Ilya A. [Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences, Moscow (Russian Federation); Chemistry Department, Lomonosov Moscow State University, Moscow (Russian Federation); Ajili, Yosra [Université Paris-Est, Laboratoire Modélisation et Simulation Multi Echelle, MSME UMR 8208 CNRS, 5 Bd Descartes, 77454 Marne-La-Vallée (France); Laboratoire de Spectroscopie Atomique, Moléculaire et Applications - LSAMA Université de Tunis El Manar (Tunisia); Vigasin, Andrei A. [Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences, Moscow (Russian Federation); Jaidane, Nejm Eddine [Laboratoire de Spectroscopie Atomique, Moléculaire et Applications - LSAMA Université de Tunis El Manar (Tunisia); Hochlaf, Majdi [Université Paris-Est, Laboratoire Modélisation et Simulation Multi Echelle, MSME UMR 8208 CNRS, 5 Bd Descartes, 77454 Marne-La-Vallée (France)

2014-06-21

We present an extensive study of the four-dimensional potential energy surface (4D-PES) of the carbon dioxide dimer, (CO{sub 2}){sub 2}. This PES is developed over the set of intermolecular coordinates. The electronic computations are carried out at the explicitly correlated coupled cluster method with single, double, and perturbative triple excitations [CCSD(T)-F12] level of theory in connection with the augmented correlation-consistent aug-cc-pVTZ basis set. An analytic representation of the 4D-PES is derived. Our extensive calculations confirm that “Slipped Parallel” is the most stable form and that the T-shaped structure corresponds to a transition state. Later on, this PES is employed for the calculations of the vibrational energy levels of the dimer. Moreover, the temperature dependence of the dimer second virial coefficient and of the first spectral moment of rototranslational collision-induced absorption spectrum is derived. For both quantities, a good agreement is found between our values and the experimental data for a wide range of temperatures. This attests to the high quality of our PES. Generally, our PES and results can be used for modeling CO{sub 2} supercritical fluidity and examination of its role in planetary atmospheres. It can be also incorporated into dynamical computations of CO{sub 2} capture and sequestration. This allows deep understanding, at the microscopic level, of these processes.

Synthesis of an estradiol glucuronide derivative and investigation of its radiopharmaceutical potential

Energy Technology Data Exchange (ETDEWEB)

Biber, F.Z. [Department of Nuclear Applications, Institute of Nuclear Sciences, Ege University, 35100 Bornova Izmir (Turkey)]. E-mail: fazilet.zumrut.biber@ege.edu.tr; Unak, P. [Department of Nuclear Applications, Institute of Nuclear Sciences, Ege University, 35100 Bornova Izmir (Turkey); Ertay, T. [Department of Nuclear Medicine, Faculty of Medicine, Dokuz Eylul University, Inciralti Izmir (Turkey); Medine, E.I. [Department of Nuclear Applications, Institute of Nuclear Sciences, Ege University, 35100 Bornova Izmir (Turkey); Zihnioglu, F. [Department of Biochemistry, Faculty of Sciences, Ege University, 35100 Bornova Izmir (Turkey); Tasci, C. [Department of Biochemistry, Faculty of Sciences, Ege University, 35100 Bornova Izmir (Turkey); Durak, H. [Department of Biochemistry, Faculty of Sciences, Ege University, 35100 Bornova Izmir (Turkey)

2006-07-15

The aim of the current study was to synthesize a derivative of estradiol glucuronide, which is able to be labeled with {sup 99m}Tc and to investigate its radiopharmaceutical potential using imaging and biodistribution studies. An estrogen derivative, {beta}-estradiol (1,3,5,[10]-estratriene-3,17{beta}-diol) attached to diethylenetriamine pentaacetic acid (DTPA) was synthesized in six steps. At the end of these steps a compound of estradiol and DTPA derivative called deoxy demethyl homoestradiolyl diethylenetriamine pentaacetic acid (ESTDTPA) was synthesized. Afterwards, this compound was reacted with UDP-glucuronyl transferase (UDPGT). Following the glucuronidation reaction, the product called deoxy demethyl homoestradiolyl diethylenetriamine pentaaceticacid-glucuronide (ESTDTPAG) was obtained. Synthesized products were purified using high performance liquid chromatography (HPLC). The identification of the purified products and impurities were also established using HPLC. Synthesized compound was labeled with {sup 99m}Tc. Thin layer radio chromatography (TLRC) technique was used to determine their radiochemical yields and stabilities. Labeling yield was over 96%. The biodistribution studies were performed on female Albino Wistar rats. The activity per gram tissue was calculated and time-activity curves were plotted. The target organs (tumor, as well as uterus, ovaries, adrenals and other ER containing tissues) retain the estradiol derivative longer than nontarget organs, but even these lost most of their activity within a few hours. In addition, the imaging studies were performed on normal and tumor bearing female Albino Wistar rats using Camstar XR/T gamma camera. In {gamma}-scintigraphic imaging studies with {sup 99m}Tc-ESTDTPAG the breast tumors could be well visualized up to 24 h.

Dynamic Support Culture of Murine Skeletal Muscle-Derived Stem Cells Improves Their Cardiogenic Potential In Vitro

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Klaus Neef

2015-01-01

Full Text Available Ischemic heart disease is the main cause of death in western countries and its burden is increasing worldwide. It typically involves irreversible degeneration and loss of myocardial tissue leading to poor prognosis and fatal outcome. Autologous cells with the potential to regenerate damaged heart tissue would be an ideal source for cell therapeutic approaches. Here, we compared different methods of conditional culture for increasing the yield and cardiogenic potential of murine skeletal muscle-derived stem cells. A subpopulation of nonadherent cells was isolated from skeletal muscle by preplating and applying cell culture conditions differing in support of cluster formation. In contrast to static culture conditions, dynamic culture with or without previous hanging drop preculture led to significantly increased cluster diameters and the expression of cardiac specific markers on the protein and mRNA level. Whole-cell patch-clamp studies revealed similarities to pacemaker action potentials and responsiveness to cardiac specific pharmacological stimuli. This data indicates that skeletal muscle-derived stem cells are capable of adopting enhanced cardiac muscle cell-like properties by applying specific culture conditions. Choosing this route for the establishment of a sustainable, autologous source of cells for cardiac therapies holds the potential of being clinically more acceptable than transgenic manipulation of cells.

Symmetric bi-pyridyl banana-shaped molecule and its intermolecular hydrogen bonding liquid-crystalline complexes

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Sui, Dan; Hou, Qiufei; Chai, Jia; Ye, Ling; Zhao, Liyan; Li, Min; Jiang, Shimei

2008-11-01

A new symmetric bi-pyridyl banana-shaped molecule 1,3-phenylene diisonicotinate (PDI) was designed and synthesized. Its molecular structure was confirmed by FTIR, Elemental analysis and 1H NMR. X-ray crystallographic study reveals that there is an angle of approximate 118° among the centroids of the three rings (pyridyl-phenyl-pyridyl) in each PDI molecule indicating a desired banana shape. In addition, a series of liquid crystal complexes nBA:PDI:nBA induced by intermolecular hydrogen bonding between PDI (proton acceptor) and 4-alkoxybenzoic acids (nBA, proton donor) were synthesized and characterized. The mesomorphism properties and optical textures of the complex of nBA:PDI:nBA were investigated by differential scanning calorimetry, polarizing optical microscope and X-ray diffraction.

Intermolecular Force Field Parameters Optimization for Computer Simulations of CH4 in ZIF-8

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Phannika Kanthima

2016-01-01

Full Text Available The differential evolution (DE algorithm is applied for obtaining the optimized intermolecular interaction parameters between CH4 and 2-methylimidazolate ([C4N2H5]− using quantum binding energies of CH4-[C4N2H5]− complexes. The initial parameters and their upper/lower bounds are obtained from the general AMBER force field. The DE optimized and the AMBER parameters are then used in the molecular dynamics (MD simulations of CH4 molecules in the frameworks of ZIF-8. The results show that the DE parameters are better for representing the quantum interaction energies than the AMBER parameters. The dynamical and structural behaviors obtained from MD simulations with both sets of parameters are also of notable differences.

Isoprene emission potentials from European oak forests derived from canopy flux measurements: an assessment of uncertainties and inter-algorithm variability

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B. Langford

2017-12-01

Full Text Available Biogenic emission algorithms predict that oak forests account for ∼ 70 % of the total European isoprene budget. Yet the isoprene emission potentials (IEPs that underpin these model estimates are calculated from a very limited number of leaf-level observations and hence are highly uncertain. Increasingly, micrometeorological techniques such as eddy covariance are used to measure whole-canopy fluxes directly, from which isoprene emission potentials can be calculated. Here, we review five observational datasets of isoprene fluxes from a range of oak forests in the UK, Italy and France. We outline procedures to correct the measured net fluxes for losses from deposition and chemical flux divergence, which were found to be on the order of 5–8 and 4–5 %, respectively. The corrected observational data were used to derive isoprene emission potentials at each site in a two-step process. Firstly, six commonly used emission algorithms were inverted to back out time series of isoprene emission potential, and then an average isoprene emission potential was calculated for each site with an associated uncertainty. We used these data to assess how the derived emission potentials change depending upon the specific emission algorithm used and, importantly, on the particular approach adopted to derive an average site-specific emission potential. Our results show that isoprene emission potentials can vary by up to a factor of 4 depending on the specific algorithm used and whether or not it is used in a big-leaf or canopy environment (CE model format. When using the same algorithm, the calculated average isoprene emission potential was found to vary by as much as 34 % depending on how the average was derived. Using a consistent approach with version 2.1 of the Model for Emissions of Gases and Aerosols from Nature (MEGAN, we derive new ecosystem-scale isoprene emission potentials for the five measurement sites: Alice Holt, UK (10 500 ± 2500�

Synthesis and study of thiocarbonate derivatives of choline as potential inhibitors of acetylcholinesterase.

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Boyle, N A; Talesa, V; Giovannini, E; Rosi, G; Norton, S J

1997-09-12

Fourteen alkyl and aryl thiocarbonate derivatives of choline were synthesized and studied as potential inhibitors of acetylcholinesterase (AChE). Twelve of the compounds inhibited AChEs derived from calf forebrain, human red blood cells, and octopus brain ranging from low to moderately high inhibition potency. The concentration of each inhibitory compound giving 50% inhibition of enzyme activity (IC50 values, which ranged from 1 x 10(-2) to 8 x 10(-7) M) was determined and is reported; inhibitor constants (Ki values) for the most inhibitory compounds, (1-pentylthiocarbonyl)choline chloride and (1-heptylthiocarbonyl)choline chloride, were calculated from kinetic data and are also reported. The inhibitors are competitive with substrate, and they are not hydrolyzed by the AChE activities. Certain of these new compounds may provide direction for the development of new drugs that have anticholinesterase activity and may be used for the treatment of Alzheimer's disease.

Rational design of viscosity reducing mutants of a monoclonal antibody: hydrophobic versus electrostatic inter-molecular interactions.

Science.gov (United States)

Nichols, Pilarin; Li, Li; Kumar, Sandeep; Buck, Patrick M; Singh, Satish K; Goswami, Sumit; Balthazor, Bryan; Conley, Tami R; Sek, David; Allen, Martin J

2015-01-01

High viscosity of monoclonal antibody formulations at concentrations ≥100 mg/mL can impede their development as products suitable for subcutaneous delivery. The effects of hydrophobic and electrostatic intermolecular interactions on the solution behavior of MAB 1, which becomes unacceptably viscous at high concentrations, was studied by testing 5 single point mutants. The mutations were designed to reduce viscosity by disrupting either an aggregation prone region (APR), which also participates in 2 hydrophobic surface patches, or a negatively charged surface patch in the variable region. The disruption of an APR that lies at the interface of light and heavy chain variable domains, VH and VL, via L45K mutation destabilized MAB 1 and abolished antigen binding. However, mutation at the preceding residue (V44K), which also lies in the same APR, increased apparent solubility and reduced viscosity of MAB 1 without sacrificing antigen binding or thermal stability. Neutralizing the negatively charged surface patch (E59Y) also increased apparent solubility and reduced viscosity of MAB 1, but charge reversal at the same position (E59K/R) caused destabilization, decreased solubility and led to difficulties in sample manipulation that precluded their viscosity measurements at high concentrations. Both V44K and E59Y mutations showed similar increase in apparent solubility. However, the viscosity profile of E59Y was considerably better than that of the V44K, providing evidence that inter-molecular interactions in MAB 1 are electrostatically driven. In conclusion, neutralizing negatively charged surface patches may be more beneficial toward reducing viscosity of highly concentrated antibody solutions than charge reversal or aggregation prone motif disruption.

Moringa oleifera Seed Derivatives as Potential Bio-Coagulant for Microalgae Chlorella sp. Harvesting

International Nuclear Information System (INIS)

Azizah Endut; Azizah Endut; Siti Hajar Abdul Hamid; Fathurrahman Lananan; Helena Khatoon

2016-01-01

Microalgae is an economical and potential raw material of biomass energy, which offer a wide range of commercial potential to produce valuable substances for applications in aquaculture feed, pharmaceutical purposes and bio fuels production. However, lack of an economical, efficient and convenient method to harvest microalgae is a bottleneck to boost their full-scale application. Hence, this study was performed to investigate the potentialities of Moringa oleifera seed derivatives as an environmentally bio-coagulant to harvest microalgae Chlorella sp. biomass from the water column, which acts as a binder to coagulate particulate impurities to form larger aggregates. Results shown M. oleifera to have better biomass recovery of 122.51 % as compared to 37.08 % of alum at similar dosages of 10 mgL"-"1. In addition, it was found that the zeta potential values of mixed microalgae-coagulant suspension shows positive correlation on the flocculation parameters. For biomass recovery, the correlation for M. oleifera protein powder showed the R"2-value of 0.9565 whereas the control chemical flocculant, alum with the R"2-value of 0.7920. It was evidence that M. oleifera has a great potential in efficient and economical for environmentally microalgae harvesting and the adaptation of biological harvesting technology especially for the purpose of aquaculture feed in Malaysia. (author)

Intermolecular interactions between B. mori silk fibroin and poly(L-lactic acid) in electrospun composite nanofibrous scaffolds

Energy Technology Data Exchange (ETDEWEB)

Taddei, Paola, E-mail: paola.taddei@unibo.it [Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Via Belmeloro 8/2, 40126 Bologna (Italy); Tozzi, Silvia [Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Via Belmeloro 8/2, 40126 Bologna (Italy); Zuccheri, Giampaolo [Dipartimento di Farmacia e Biotecnologie e Centro Interdipartimentale di Ricerca Industriale Scienze della Vita e Tecnologie per la Salute, Università di Bologna, Via Irnerio 48, 40126 Bologna (Italy); Centro S3, Istituto Nanoscienze, Consiglio Nazionale delle Ricerche, Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali (Italy); Martinotti, Simona; Ranzato, Elia [Dipartimento di Scienze e Innovazione Tecnologica, DiSIT, Università del Piemonte Orientale, viale Teresa Michel 11, 15121 Alessandria (Italy); Chiono, Valeria; Carmagnola, Irene [Dipartimento di Ingegneria Meccanica e Aerospaziale, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Tsukada, Masuhiro [Division of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, 3-15-1, Tokida, Ueda, Nagano 386-8567 (Japan)

2017-01-01

In this study, composite nanofibrous scaffolds were obtained by electrospinning a trifluoroacetic acid solution containing B. mori silk fibroin (SF) and poly(L-lactic acid) (PLLA) in a 1:1 weight ratio. SF, PLLA and SF/PLLA nanofibres were prepared with average diameter sizes of 360 ± 90 nm, 470 ± 240 nm and 580 ± 220 nm, respectively, as assessed by SEM analysis. Vibrational and thermal analyses showed that upon blending in the SF/PLLA nanofibres, the crystallisation of PLLA was hindered by the presence of SF, which crystallized preferentially and underwent conformational changes that did not significantly change its prevailing β-sheet structure. The two components were thermodynamically compatible and the intermolecular interactions between them were revealed for the first time. Human keratinocytes were cultured on nanofibres and their viability and proliferation were determined. Preliminary in vitro tests showed that the incorporation of SF into the PLLA component enhanced cell adhesion and proliferation with respect to the unfunctionalised material. SF has been successfully used to modify the biomaterial properties and confirmed to be an efficient bioactive protein to mediate cell-biomaterial interaction. - Highlights: • Composite silk fibroin-poly(L-lactic acid) scaffolds were obtained by electrospinning. • Intermolecular interactions between SF and PLLA were revealed for the first time. • Upon blending, the crystallisation of PLLA was hindered by the presence of SF. • SF crystallized preferentially and maintained its prevailing β-sheet structure. • The incorporation of SF into PLLA enhanced human keratinocytes adhesion and proliferation.

Evaluation of hematopoietic potential generated by transplantation of muscle-derived stem cells in mice.

Science.gov (United States)

Farace, Francoise; Prestoz, Laetitita; Badaoui, Sabrina; Guillier, Martine; Haond, Celine; Opolon, Paule; Thomas, Jean-Leon; Zalc, Bernard; Vainchenker, William; Turhan, Ali G

2004-02-01

Muscle tissue of adult mice has been shown to contain stem cells with hematopoietic repopulation ability in vivo. To determine the functional characteristics of stem cells giving rise to this hematopoietic activity, we have performed hematopoietic reconstitution experiments by the use of muscle versus marrow transplantation in lethally irradiated mice and followed the fate of transplanted cells by Y-chimerism using PCR and fluorescence in situ hybridization (FISH) analysis. We report here that transplantation of murine muscle generate a major hematopoietic chimerism at the level of CFU-C, CFU-S, and terminally-differentiated cells in three generations of lethally irradiated mice followed up to 1 year after transplantation. This potential is totally abolished when muscle grafts were performed by the use of muscle from previously irradiated mice. As compared to marrow transplantation, muscle transplants were able to generate similar potencies to give rise to myeloid, T, B, and natural killer (NK) cells. Interestingly, marrow stem cells that have been generated in primary and then in secondary recipients were able to contribute efficiently to myofibers in the muscle tissue of tertiary recipients. Altogether, our data demonstrate that muscle-derived stem cells present a major hematopoietic repopulating ability with evidence of self-replication in vivo. They are radiation-sensitive and similar to marrow-derived stem cells in terms of their ability to generate multilineage hematopoiesis. Finally, our data demonstrate that muscle-derived hematopoietic stem cells do not lose their ability to contribute to myofiber generation after at least two rounds of serial transplantation, suggesting a potential that is probably equivalent to that generated by marrow transplantation.

Design, Synthesis and Biological Evaluation of C(6-Modified Celastrol Derivatives as Potential Antitumor Agents

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Kaiyong Tang

2014-07-01

Full Text Available New six C6-celastrol derivatives were designed, synthesized, and evaluated for their in vitro cytotoxic activities against nine human cancer cell lines (BGC-823, H4, Bel7402, H522, Colo 205, HepG2 and MDA-MB-468. The results showed that most of the compounds displayed potent inhibition against BGC823, H4, and Bel7402, with IC50s of 1.84–0.39 μM. The best compound NST001A was tested in an in vivo antitumor assay on nude mice bearing Colo 205 xenografts, and showed significant inhibition of tumor growth at low concentrations. Therefore, celastrol C-6 derivatives are potential drug candidates for treating cancer.

Potential of cancer cell-derived exosomes in clinical application: a review of recent research advances.

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Sun, Yu; Liu, Jing

2014-06-01

Exosomes are 30- to 100-nm, membrane-bound vesicles that are released by most types of cells, including tumor cells. Exosomes contain a great variety of bioactive molecules, including signal peptides, microRNA, lipids, and DNA. In cancer, tumor cells aberrantly secrete large quantities of exosomes to transport paracrine signals or to contribute to tumor-environment interaction at a distance. The goal of this review was to discuss the recent advances on the mechanism of cancer-derived exosomes in tumor regulation. Pertinent articles and abstracts were identified through searches of PubMed for literature published from 1983 to December 2013. Search terms included exosome, tumor, cancer, diagnosis, and therapy. All of the exposed evidence points to communication between cancer cells and their surroundings, either mediated by cancer cell-derived exosomes or by stromal cell-derived exosomes. This communication probably supports tumor proliferation, motility, invasion, angiogenesis, and premetastatic niche preparation. In addition, recent research implies that cancer cell-derived exosomes play a suppressive role in cancer-directed immune response. The biomarkers detected in bodily fluid-derived exosomes imply a potential for exosomes in cancer diagnosis. Also, exosomes could be used as a vehicle to selectively deliver therapeutic nucleic-acid drugs or conventional drugs for tumor therapy. The tolerability and feasibility of cancer exosomes in diagnosis and therapy need to be further evaluated. Copyright © 2014 Elsevier HS Journals, Inc. All rights reserved.

Atomistic modeling of zirconium hydride precipitation: methodology for deriving a tight-binding potential

International Nuclear Information System (INIS)

Dufresne, Alice

2014-01-01

The zirconium-hydrogen system is of nuclear safety interest, as the hydride precipitation leads to the cladding embrittlement, which is made of zirconium-based alloys. The cladding is the first safety barrier confining the radioactive products: its integrity shall be kept during the entire fuel-assemblies life, in reactor, including accidental situation, and post-operation (transport and storage). Many uncertainties remain regarding the hydrides precipitation kinetics and the local stress impact on their precipitation. The atomic scale modeling of this system would bring clarifications on the relevant mechanisms. The usual atomistic modeling methods are based on thermo-statistic approaches, whose precision and reliability depend on the interatomic potential used. However, there was no potential allowing a rigorous study of the Zr-H system. The present work has indeed addressed this issue: a new tight-binding potential for zirconium hydrides modeling is now available. Moreover, this thesis provides a detailed manual for deriving such potentials accounting for spd hybridization, and fitted here on DFT results. This guidebook has be written in light of modeling a pure transition metal followed by a metal-covalent coupling (metallic carbides, nitrides and silicides). (author)

Human iPS Cell-Derived Germ Cells: Current Status and Clinical Potential

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Tetsuya Ishii

2014-10-01

Full Text Available Recently, fertile spermatozoa and oocytes were generated from mouse induced pluripotent (iPS cells using a combined in vitro and in vivo induction system. With regard to germ cell induction from human iPS cells, progress has been made particularly in the male germline, demonstrating in vitro generation of haploid, round spermatids. Although iPS-derived germ cells are expected to be developed to yield a form of assisted reproductive technology (ART that can address unmet reproductive needs, genetic and/or epigenetic instabilities abound in iPS cell generation and germ cell induction. In addition, there is still room to improve the induction protocol in the female germline. However, rapid advances in stem cell research are likely to make such obstacles surmountable, potentially translating induced germ cells into the clinical setting in the immediate future. This review examines the current status of the induction of germ cells from human iPS cells and discusses the clinical potential, as well as future directions.

Biological characteristics of human-urine-derived stem cells: potential for cell-based therapy in neurology.

Science.gov (United States)

Guan, Jun-Jie; Niu, Xin; Gong, Fei-Xiang; Hu, Bin; Guo, Shang-Chun; Lou, Yuan-Lei; Zhang, Chang-Qing; Deng, Zhi-Feng; Wang, Yang

2014-07-01

Stem cells in human urine have gained attention in recent years; however, urine-derived stem cells (USCs) are far from being well elucidated. In this study, we compared the biological characteristics of USCs with adipose-derived stem cells (ASCs) and investigated whether USCs could serve as a potential cell source for neural tissue engineering. USCs were isolated from voided urine with a modified culture medium. Through a series of experiments, we examined the growth rate, surface antigens, and differentiation potential of USCs, and compared them with ASCs. USCs showed robust proliferation ability. After serial propagation, USCs retained normal karyotypes. Cell surface antigen expression of USCs was similar to ASCs. With lineage-specific induction factors, USCs could differentiate toward the osteogenic, chondrogenic, adipogenic, and neurogenic lineages. To assess the ability of USCs to survive, differentiate, and migrate, they were seeded onto hydrogel scaffold and transplanted into rat brain. The results showed that USCs were able to survive in the lesion site, migrate to other areas, and express proteins that were associated with neural phenotypes. The results of our study demonstrate that USCs possess similar biological characteristics with ASCs and have multilineage differentiation potential. Moreover USCs can differentiate to neuron-like cells in rat brain. The present study shows that USCs are a promising cell source for tissue engineering and regenerative medicine.

In Vitro Osteogenic Potential of Green Fluorescent Protein Labelled Human Embryonic Stem Cell-Derived Osteoprogenitors

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Intekhab Islam

2016-01-01

Full Text Available Cellular therapy using stem cells in bone regeneration has gained increasing interest. Various studies suggest the clinical utility of osteoprogenitors-like mesenchymal stem cells in bone regeneration. However, limited availability of mesenchymal stem cells and conflicting evidence on their therapeutic efficacy limit their clinical application. Human embryonic stem cells (hESCs are potentially an unlimited source of healthy and functional osteoprogenitors (OPs that could be utilized for bone regenerative applications. However, limited ability to track hESC-derived progenies in vivo greatly hinders translational studies. Hence, in this study, we aimed to establish hESC-derived OPs (hESC-OPs expressing green fluorescent protein (GFP and to investigate their osteogenic differentiation potential in vitro. We fluorescently labelled H9-hESCs using a plasmid vector encoding GFP. The GFP-expressing hESCs were differentiated into hESC-OPs. The hESC-OPsGFP+ stably expressed high levels of GFP, CD73, CD90, and CD105. They possessed osteogenic differentiation potential in vitro as demonstrated by increased expression of COL1A1, RUNX2, OSTERIX, and OPG transcripts and mineralized nodules positive for Alizarin Red and immunocytochemical expression of osteocalcin, alkaline phosphatase, and collagen-I. In conclusion, we have demonstrated that fluorescently labelled hESC-OPs can maintain their GFP expression for the long term and their potential for osteogenic differentiation in vitro. In future, these fluorescently labelled hESC-OPs could be used for noninvasive assessment of bone regeneration, safety, and therapeutic efficacy.

Effect of donor orientation on ultrafast intermolecular electron transfer in coumarin-amine systems

International Nuclear Information System (INIS)

Singh, P. K.; Nath, S.; Bhasikuttan, A. C.; Kumbhakar, M.; Mohanty, J.; Sarkar, S. K.; Mukherjee, T.; Pal, H.

2008-01-01

Effect of donor amine orientation on nondiffusive ultrafast intermolecular electron transfer (ET) reactions in coumarin-amine systems has been investigated using femtosecond fluorescence upconversion measurements. Intermolecular ET from different aromatic and aliphatic amines used as donor solvents to the excited coumarin-151 (C151) acceptor occurs with ultrafast rates such that the shortest fluorescence lifetime component (τ 1 ) is the measure of the fastest ET rate (τ 1 =τ ET fast =(k ET fast ) -1 ), assigned to the C151-amine contact pairs in which amine donors are properly oriented with respect to C151 to maximize the acceptor-donor electronic coupling (V el ). It is interestingly observed that as the amine solvents are diluted by suitable diluents (either keeping solvent dielectric constant similar or with increasing dielectric constant), the τ 1 remains almost in the similar range as long as the amine dilution does not cross a certain critical limit, which in terms of the amine mole fraction (x A ) is found to be ∼0.4 for aromatic amines and ∼0.8 for aliphatic amines. Beyond these dilutions in the two respective cases of the amine systems, the τ 1 values are seen to increase very sharply. The large difference in the critical x A values involving aromatic and aliphatic amine donors has been rationalized in terms of the largely different orientational restrictions for the ET reactions as imposed by the aliphatic (n-type) and aromatic (π-type) nature of the amine donors [A. K. Satpati et al., J. Mol. Struct. 878, 84 (2008)]. Since the highest occupied molecular orbital (HOMO) of the n-type aliphatic amines is mostly centralized at the amino nitrogen, only some specific orientations of these amines with respect to the close-contact acceptor dye [also of π-character; A. K. Satpati et al., J. Mol. Struct. 878, 84 (2008) and E. W. Castner et al., J. Phys. Chem. A 104, 2869 (2000)] can give suitable V el and thus ultrafast ET reaction. In contrary, the

A comparative study of the broadening effect on rotational lines by methane and noble gases

International Nuclear Information System (INIS)

Kircz, J.G.

1979-01-01

Line broadening measurements for the mixtures HCl-CH 4 and HCl-CD 4 have been performed and the results of these experiments are reported. Current theoretical models for the systems studied are briefly discussed. In order to identify specific effects the authors have tried to find a generalisation for linewidth cross-sections for the HCl-noble gas systems. This is done in the spirit of the well known corresponding state treatment in statistical mechanics in an attempt to find, in terms of reduced variables, a generalised intermolecular potential for these systems. Extensive calculations on the HCl-Ar and HCl-Kr intermolecular potentials, as derived from linewidth measurements, are reported in an attempt to extract a more exact potential for these systems. The results are compared with other recent results from the literature. The use of a semi-empirical method for the evaluation of the experimental data is described. This empirical method has been used in a comparison between the HCl-noble gas experiments and the present experiments of HCl-methane. The possibility of splitting the observed data into a 'noble gas' part and a 'extra' part due to the intermolecular interactions which result from the coupling of the HCl rotations with the internal degrees of freedom of the methane molecules is discussed. (Auth.)

Synthesis of Phthalimide Derivatives as Potential PPAR-γ Ligands

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So Hyeon Eom

2016-06-01

Full Text Available Paecilocin A, a phthalide derivative isolated from the jellyfish-derived fungus Paecilomyces variotii, activates PPAR-γ (Peroxisome proliferator-activated receptor gamma in rat liver Ac2F cells. Based on a SAR (Structure-activity relationships study and in silico analysis of paecilocin A-mimetic derivatives, additional N-substituted phthalimide derivatives were synthesized and evaluated for PPAR-γ agonistic activity in both murine liver Ac2F cells and in human liver HepG2 cells by luciferase assay, and for adipogenic activity in 3T3-L1 cells. Docking simulation indicated PD6 was likely to bind most strongly to the ligand binding domain of PPAR-γ by establishing crucial H-bonds with key amino acid residues. However, in in vitro assays, PD1 and PD2 consistently displayed significant PPAR-γ activation in Ac2F and HepG2 cells, and adipogenic activity in 3T3-L1 preadipocytes.

Solid state synthesis, structural, physicochemical and optical properties of an inter-molecular compound: 2-hydroxy-1, 2-diphenylethanone-4-nitro-o-phenylenediamine system

Science.gov (United States)

Rai, U. S.; Singh, Manjeet; Rai, R. N.

2017-09-01

The phase diagram of 2-hydroxy-1, 2-diphenylethanone (HDPE)-4-nitro-o-phenylenediamine (NOPDA) system, determined by the thaw-melt method, gives two eutectics E1 (m p = 66.0 °C) and E2 (m p = 155.0 °C) with 0.30 and 0.55 mol fractions of NOPDA, respectively, and an 1:1 inter-molecular compound (IMC) (m p 162.0 °C). This IMC was synthesized by adopting the green synthetic method of solid state reaction. While its formation and structure were confirmed by the X-ray diffraction and spectroscopic methods, the ORTEP view gives mode of crystal packing, C‒H…O, C‒H…N, π-π stacking and the inter-molecular hydrogen bonding in the compound. The single crystal of the IMC shows 53% transmission and emits significantly higher dual fluorescence, and the band gap was computed to be 3.04 eV. The values of solubility of the IMC, measured in the temperature range 304-322 K, satisfy the mole fraction (X) and temperature equation: Xeq= 5.1324 × 10-7 e 0.01356T.

Synthesis of functionalized pyrazolopyran derivatives: comparison of ...

Indian Academy of Sciences (India)

Administrator

1. The crystal structure as elucidated by X-ray diffraction methods shows the presence of different intermolecular interactions, and the nature and energetics associated with these inter- actions have been characterized using PIXEL software.

Chondrogenic potential of canine articular cartilage derived cells (cACCs

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Nowak Urszula

2016-01-01

Full Text Available In the present paper, the potential of canine articular cartilage-derived cells (cACCs for chondrogenic differentiation was evaluated. The effectiveness of cACCs’ lineage commitment was analyzed after 14 days of culture in chondorgenic and non-chondrogenic conditions. Formation of proteoglycan-rich extracellular matrix was assessed using histochemical staining – Alcian Blue and Safranin-O, while elemental composition was determined by means of SEM-EDX. Additionally, ultrastructure of cACCs was evaluated using TEM. The expression of genes involved in chondrogenesis was monitored with quantitative Real Time PCR. Results obtained indicate that the potential of cACCs for cartilagous extracellular matrix formation may be maintained only in chondrogenic cultures. The formation of specific chondro-nodules was not observed in a non-chondrogenic culture environment. The analysis of cACCs’ ultrastructure, both in non-chondrogenic and chondrogenic cultures, revealed well-developed rough endoplasmatic reticulum and presence of mitochondria. The cACCs in chondrogenic medium shed an increased number of microvesicles. Furthermore, it was shown that the extracellular matrix of cACCs in chondrogenic cultures is rich in potassium and molybdenum. Additionally, it was determined that gene expression of collagen type II, aggrecan and SOX-9 was significantly increased during chondrogenic differentiation of cACCs. Results obtained indicate that the culture environment may significantly influence the cartilage phenotype of cACCs during long term culture.

Analytic equation of state for FCC C60 solid based on analytic mean-field potential approach

International Nuclear Information System (INIS)

Sun Jiuxun

2006-01-01

The analytic mean-field approach (AMFP) was applied to the FCC C60 solid. For the intermolecular forces the Girifalco potential has been utilized. The analytic expressions for the Helmholtz free energy, internal energy and equation of state have been derived. The numerical results of thermodynamic quantities are compared with the molecular dynamic (MD) simulations and the unsymmetrized self-consistent field approach (CUSF) in the literature. It is shown that our AMFP results are in good agreement with the MD data both at low and high temperatures. The results of CUSF are in accordance with the AMFP at low temperature, but at high temperature the difference becomes prominent. Especially the AMFP predicted that the FCC C60 solid is stable upto 2202 K, the spinodal temperature, in good agreement with 2320 K from the MD simulation. However, the CUST just gives 1916 K, a temperature evidently lower than the MD data. The AMFP qualifies as a useful approach that can reasonably consider the anharmonic effects at high temperature

Interplay between intramolecular and intermolecular structures of 1,1,2,2-tetrachloro-1,2-difluoroethane

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Rovira-Esteva, M.; Murugan, N. A.; Pardo, L. C.; Busch, S.; Tamarit, J. Ll.; Pothoczki, Sz.; Cuello, G. J.; Bermejo, F. J.

2011-08-01

We report on the interplay between the short-range order of molecules in the liquid phase of 1,1,2,2-tetrachloro-1,2-difluoroethane and the possible molecular conformations, trans and gauche. Two complementary approaches have been used to get a comprehensive picture: analysis of neutron-diffraction data by a Bayesian fit algorithm and a molecular dynamics simulation. The results of both show that the population of trans and gauche conformers in the liquid state can only correspond to the gauche conformer being more stable than the trans conformer. Distinct conformer geometries induce distinct molecular short-range orders around them, suggesting that a deep intra- and intermolecular interaction coupling is energetically favoring one of the conformers by reducing the total molecular free energy.

Propagator formalism and computer simulation of restricted diffusion behaviors of inter-molecular multiple-quantum coherences

International Nuclear Information System (INIS)

Cai Congbo; Chen Zhong; Cai Shuhui; Zhong Jianhui

2005-01-01

In this paper, behaviors of single-quantum coherences and inter-molecular multiple-quantum coherences under restricted diffusion in nuclear magnetic resonance experiments were investigated. The propagator formalism based on the loss of spin phase memory during random motion was applied to describe the diffusion-induced signal attenuation. The exact expression of the signal attenuation under the short gradient pulse approximation for restricted diffusion between two parallel plates was obtained using this propagator method. For long gradient pulses, a modified formalism was proposed. The simulated signal attenuation under the effects of gradient pulses of different width based on the Monte Carlo method agrees with the theoretical predictions. The propagator formalism and computer simulation can provide convenient, intuitive and precise methods for the study of the diffusion behaviors

Derivative chameleons

International Nuclear Information System (INIS)

Noller, Johannes

2012-01-01

We consider generalized chameleon models where the conformal coupling between matter and gravitational geometries is not only a function of the chameleon field φ, but also of its derivatives via higher order co-ordinate invariants (such as ∂ μ φ∂ μ φ,□φ,...). Specifically we consider the first such non-trivial conformal factor A(φ,∂ μ φ∂ μ φ). The associated phenomenology is investigated and we show that such theories have a new generic mass-altering mechanism, potentially assisting the generation of a sufficiently large chameleon mass in dense environments. The most general effective potential is derived for such derivative chameleon setups and explicit examples are given. Interestingly this points us to the existence of a purely derivative chameleon protected by a shift symmetry for φ → φ+c. We also discuss potential ghost-like instabilities associated with mass-lifting mechanisms and find another, mass-lowering and instability-free, branch of solutions. This suggests that, barring fine-tuning, stable derivative models are in fact typically anti-chameleons that suppress the field's mass in dense environments. Furthermore we investigate modifications to the thin-shell regime and prove a no-go theorem for chameleon effects in non-conformal geometries of the disformal type

Derivative chameleons

Energy Technology Data Exchange (ETDEWEB)

Noller, Johannes, E-mail: johannes.noller08@imperial.ac.uk [Theoretical Physics, Blackett Laboratory, Imperial College London, Prince Consort Road, London, SW7 2BZ (United Kingdom)

2012-07-01

We consider generalized chameleon models where the conformal coupling between matter and gravitational geometries is not only a function of the chameleon field φ, but also of its derivatives via higher order co-ordinate invariants (such as ∂{sub μ}φ∂{sup μ}φ,□φ,...). Specifically we consider the first such non-trivial conformal factor A(φ,∂{sub μ}φ∂{sup μ}φ). The associated phenomenology is investigated and we show that such theories have a new generic mass-altering mechanism, potentially assisting the generation of a sufficiently large chameleon mass in dense environments. The most general effective potential is derived for such derivative chameleon setups and explicit examples are given. Interestingly this points us to the existence of a purely derivative chameleon protected by a shift symmetry for φ → φ+c. We also discuss potential ghost-like instabilities associated with mass-lifting mechanisms and find another, mass-lowering and instability-free, branch of solutions. This suggests that, barring fine-tuning, stable derivative models are in fact typically anti-chameleons that suppress the field's mass in dense environments. Furthermore we investigate modifications to the thin-shell regime and prove a no-go theorem for chameleon effects in non-conformal geometries of the disformal type.

PAMAM Dendrimers as Potential Carriers of Gadolinium Complexes of Iminodiacetic Acid Derivatives for Magnetic Resonance Imaging

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Magdalena Markowicz-Piasecka

2015-01-01

Full Text Available This is the first study describing the utilization of PAMAM dendrimers as delivery vehicles of novel magnetic resonance imaging (MRI contrast agents. The purpose of this paper was to establish the potential of G4 PAMAM dendrimers as carriers of gadolinium complexes of iminodiacetic acid derivatives and determine imaging properties of synthesized compounds in in vivo studies. Furthermore, we examined the influence of four synthesized complexes on the process of clot formation, stabilization, and lysis and on amidolytic activity of thrombin. Biodistribution studies have shown that the compounds composed of PAMAM G4 dendrimers and gadolinium complexes of iminodiacetic acid derivatives increase signal intensity preferably in liver in range of 59–116% in MRI studies which corresponds with the greatest accumulation of gadolinium after administration of the compounds. Synthesized compounds affect kinetic parameters of the proces of clot formation, its stabilization, and lysis. However, only one synthesized compound at concentration 10-fold higher than potential plasma concentrations contributed to the increase of general parameters such as the overall potential of clot formation and lysis (↑CLAUC and total time of the process (↑T. Results of described studies provide additional insight into delivery properties of PAMAM dendrimers but simultaneously underscore the necessity for further research.

Exciplex: An Intermolecular Charge-Transfer Approach for TADF.

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Sarma, Monima; Wong, Ken-Tsung

2018-04-03

Organic materials that display thermally activated delayed fluorescence (TADF) are a striking class of functional materials that have witnessed a booming progress in recent years. In addition to pure TADF emitters achieved by the subtle manipulations of intramolecular charge transfer processes with sophisticated molecular structures, a new class of efficient TADF-based OLEDs with emitting layer formed by blending electron donor and acceptor molecules that involve intermolecular charge transfer have also been fabricated. In contrast to pure TADF materials, the exciplex-based systems can realize small ΔEST (0-0.05 eV) much more easily since the electron and hole are positioned on two different molecules, thereby giving small exchange energy. Consequently, exciplex-based OLEDs have the prospective to maximize the TADF contribution and achieve theoretical 100% internal quantum efficiency. Therefore, the challenging issue of achieving small ΔEST in organic systems could be solved. In this article, we summarize and discuss the latest and most significant developments regarding these rapidly evolving functional materials, wherein the majority of the reported exciplex forming systems are categorized into two sub-groups, viz. (a) exciplex as TADF emitters and (b) those as hosts for fluorescent, phosphorescent and TADF dopants according to their structural features and applications. The working mechanisms of the direct electroluminescence from the donor/acceptor interface and the exciplex-forming systems as co-host for the realization of high efficiency OLEDs are reviewed and discussed. This article delivers a summary of the current progresses and achievements of exciplex-based researches and points out the future challenges to trigger more research endeavors to this growing field.

Relating derived relations as a model of analogical reasoning: reaction times and event-related potentials.

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Barnes-Holmes, Dermot; Regan, Donal; Barnes-Holmes, Yvonne; Commins, Sean; Walsh, Derek; Stewart, Ian; Smeets, Paul M; Whelan, Robert; Dymond, Simon

2005-11-01

The current study aimed to test a Relational Frame Theory (RFT) model of analogical reasoning based on the relating of derived same and derived difference relations. Experiment 1 recorded reaction time measures of similar-similar (e.g., "apple is to orange as dog is to cat") versus different-different (e.g., "he is to his brother as chalk is to cheese") derived relational responding, in both speed-contingent and speed-noncontingent conditions. Experiment 2 examined the event-related potentials (ERPs) associated with these two response patterns. Both experiments showed similar-similar responding to be significantly faster than different-different responding. Experiment 2 revealed significant differences between the waveforms of the two response patterns in the left-hemispheric prefrontal regions; different-different waveforms were significantly more negative than similar-similar waveforms. The behavioral and neurophysiological data support the RFT prediction that, all things being equal, similar-similar responding is relationally "simpler" than, and functionally distinct from, different-different analogical responding. The ERP data were fully consistent with findings in the neurocognitive literature on analogy. These findings strengthen the validity of the RFT model of analogical reasoning and supplement the behavior-analytic approach to analogy based on the relating of derived relations.

Automated grouping of action potentials of human embryonic stem cell-derived cardiomyocytes.

Science.gov (United States)

Gorospe, Giann; Zhu, Renjun; Millrod, Michal A; Zambidis, Elias T; Tung, Leslie; Vidal, Rene

2014-09-01

Methods for obtaining cardiomyocytes from human embryonic stem cells (hESCs) are improving at a significant rate. However, the characterization of these cardiomyocytes (CMs) is evolving at a relatively slower rate. In particular, there is still uncertainty in classifying the phenotype (ventricular-like, atrial-like, nodal-like, etc.) of an hESC-derived cardiomyocyte (hESC-CM). While previous studies identified the phenotype of a CM based on electrophysiological features of its action potential, the criteria for classification were typically subjective and differed across studies. In this paper, we use techniques from signal processing and machine learning to develop an automated approach to discriminate the electrophysiological differences between hESC-CMs. Specifically, we propose a spectral grouping-based algorithm to separate a population of CMs into distinct groups based on the similarity of their action potential shapes. We applied this method to a dataset of optical maps of cardiac cell clusters dissected from human embryoid bodies. While some of the nine cell clusters in the dataset are presented with just one phenotype, the majority of the cell clusters are presented with multiple phenotypes. The proposed algorithm is generally applicable to other action potential datasets and could prove useful in investigating the purification of specific types of CMs from an electrophysiological perspective.

Potential roles of cell-derived microparticles in ischemic brain disease.

Science.gov (United States)

Horstman, Lawrence L; Jy, Wenche; Bidot, Carlos J; Nordberg, Mary L; Minagar, Alireza; Alexander, J Steven; Kelley, Roger E; Ahn, Yeon S

2009-10-01

The objective of this study is to review the role of cell-derived microparticles in ischemic cerebrovascular diseases. An extensive PubMed search of literature pertaining to this study was performed in April 2009 using specific keyword search terms related to cell-derived microparticles and ischemic stroke. Some references are not cited here as it is not possible to be all inclusive or due to space limitation. Cell-derived microparticles are small membranous vesicles released from the plasma membranes of platelets, leukocytes, red cells and endothelial cells in response to diverse biochemical agents or mechanical stresses. They are the main carriers of circulating tissue factor, the principal initiator of intravascular thrombosis, and are implicated in a variety of thrombotic and inflammatory disorders. This review outlines evidence suggesting that cell-derived microparticles are involved predominantly with microvascular, as opposed to macrovascular, thrombosis. More specifically, cell-derived microparticles may substantially contribute to ischemic brain disease in several settings, as well as to neuroinflammatory conditions. If further work confirms this hypothesis, novel therapeutic strategies for minimizing cell-derived microparticles-mediated ischemia are available or can be developed, as discussed.

Vibrational Spectra of β″-Type BEDT-TTF Salts: Relationship between Conducting Property, Time-Averaged Site Charge and Inter-Molecular Distance

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Takashi Yamamoto

2012-07-01

Full Text Available The relationship between the conducting behavior and the degree of charge fluctuation in the β″-type BEDT-TTF salts is reviewed from the standpoints of vibrational spectroscopy and crystal structure. A group of β″-type ET salts demonstrates the best model compounds for achieving the above relationship because the two-dimensional structure is simple and great diversity in conducting behavior is realized under ambient pressure. After describing the requirement for the model compound, the methodology for analyzing the results of the vibrational spectra is presented. Vibrational spectroscopy provides the time-averaged molecular charge, the charge distribution in the two-dimensional layer, and the inter-molecular interactions, etc. The experimental results applied to 2/3-filled and 3/4-filled β″-type ET salts are reported. These experimental results suggest that the conducting property, the difference in the time-averaged molecular charges between the ionic and neutral-like sites, the alternation in the inter-molecular distances and the energy levels in the charge distributions are relevant to one another. The difference in the time-averaged molecular charges, ∆ρ, is a useful criterion for indicating conducting behavior. All superconductors presented in this review are characterized as small but finite ∆ρ.

Spectral investigations and DFT studies of 3,7-dihydro-1,3,7-trimethyl-1H-purine-2,6-dione (caffeine) interaction and recognition by single amino acid derived self-assembled nanostructures

Science.gov (United States)

Govindhan, R.; Karthikeyan, B.

2018-03-01

Recognition of xanthine alkaloid caffeine with 3,5-bis(trifluoromethyl)benzylamine derived peptide nanotubes (BTTPNTs) through chemical interaction have been achieved through the host-guest like interaction. DFT simulation is carried out for caffeine interacted with BTTPNTs system and also experimentally characterized by ultraviolet-visible (UV-vis) absorbance, confocal Raman spectra (CRS) with microscopic imaging (CRM), FT-Raman, surface enhanced Raman scattering (SERS), UV-diffuse reflectance spectra (UV-DRS), high resolution transmission electron microscopy (HR-TEM) and cyclic voltammetry (CV) studies. The results are used to examine the morphologies, size of the nanostructure and study of its interaction with the caffeine molecule. The results show that BTTPNTs is having potential for sensing the caffeine molecules through the binding occurred from the NH2 of tyrosine moiety of the BTTPNTs. This intermolecular association through face-to-face stacking of BTTPNTs is explained by detailed DFT calculations.

Modeling the Alzheimer Abeta17-42 fibril architecture: tight intermolecular sheet-sheet association and intramolecular hydrated cavities.

Science.gov (United States)

Zheng, Jie; Jang, Hyunbum; Ma, Buyong; Tsai, Chung-Jun; Nussinov, Ruth

2007-11-01

We investigate Abeta(17-42) protofibril structures in solution using molecular dynamics simulations. Recently, NMR and computations modeled the Abeta protofibril as a longitudinal stack of U-shaped molecules, creating an in-parallel beta-sheet and loop spine. Here we study the molecular architecture of the fibril formed by spine-spine association. We model in-register intermolecular beta-sheet-beta-sheet associations and study the consequences of Alzheimer's mutations (E22G, E22Q, E22K, and M35A) on the organization. We assess the structural stability and association force of Abeta oligomers with different sheet-sheet interfaces. Double-layered oligomers associating through the C-terminal-C-terminal interface are energetically more favorable than those with the N-terminal-N-terminal interface, although both interfaces exhibit high structural stability. The C-terminal-C-terminal interface is essentially stabilized by hydrophobic and van der Waals (shape complementarity via M35-M35 contacts) intermolecular interactions, whereas the N-terminal-N-terminal interface is stabilized by hydrophobic and electrostatic interactions. Hence, shape complementarity, or the "steric zipper" motif plays an important role in amyloid formation. On the other hand, the intramolecular Abeta beta-strand-loop-beta-strand U-shaped motif creates a hydrophobic cavity with a diameter of 6-7 A, allowing water molecules and ions to conduct through. The hydrated hydrophobic cavities may allow optimization of the sheet association and constitute a typical feature of fibrils, in addition to the tight sheet-sheet association. Thus, we propose that Abeta fiber architecture consists of alternating layers of tight packing and hydrated cavities running along the fibrillar axis, which might be possibly detected by high-resolution imaging.

A consistent derivation of the real and imaginary parts of the heavy ion potential below and above the Coulomb barrier

International Nuclear Information System (INIS)

Vinh Mau, N.

1987-03-01

In a model including approximately a large set of non elastic channels, the real and imaginary potentials are consistently derived. The anomaly of the real potential which sharply increases in the vicinity of the Coulomb barrier where the imaginary potential is strongly reduced is studied in 16 0+ 40 Ca and 16 O+ 208 Pb systems. The results on the imaginary potential are discussed and compared to our previous calculation

Computational study of molecular electrostatic potential, docking and dynamics simulations of gallic acid derivatives as ABL inhibitors.

Science.gov (United States)

Raghi, K R; Sherin, D R; Saumya, M J; Arun, P S; Sobha, V N; Manojkumar, T K

2018-04-05

Chronic myeloid leukemia (CML), a hematological malignancy arises due to the spontaneous fusion of the BCR and ABL gene, resulting in a constitutively active tyrosine kinase (BCR-ABL). Pharmacological activity of Gallic acid and 1,3,4-Oxadiazole as potential inhibitors of ABL kinase has already been reported. Objective of this study is to evaluate the ABL kinase inhibitory activity of derivatives of Gallic acid fused with 1,3,4-Oxadiazole moieties. Attempts have been made to identify the key structural features responsible for drug likeness of the Gallic acid and the 1,3,4-Oxadiazole ring using molecular electrostatic potential maps (MESP). To investigate the inhibitory activity of Gallic acid derivatives towards the ABL receptor, we have applied molecular docking and molecular dynamics (MD) simulation approaches. A comparative study was performed using Bosutinib as the standard which is an approved CML drug acting on the same receptor. Furthermore, the novel compounds designed and reported here in were evaluated for ADME properties and the results indicate that they show acceptable pharmacokinetic properties. Accordingly these compounds are predicted to be drug like with low toxicity potential. Copyright © 2018 Elsevier Ltd. All rights reserved.

Complete relaxation and conformational exchange matrix (CORCEMA) analysis of intermolecular saturation transfer effects in reversibly forming ligand-receptor complexes.

Science.gov (United States)

Jayalakshmi, V; Krishna, N Rama

2002-03-01

A couple of recent applications of intermolecular NOE (INOE) experiments as applied to biomolecular systems involve the (i) saturation transfer difference NMR (STD-NMR) method and (ii) the intermolecular cross-saturation NMR (ICS-NMR) experiment. STD-NMR is a promising tool for rapid screening of a large library of compounds to identify bioactive ligands binding to a target protein. Additionally, it is also useful in mapping the binding epitopes presented by a bioactive ligand to its target protein. In this latter application, the STD-NMR technique is essentially similar to the ICS-NMR experiment, which is used to map protein-protein or protein-nucleic acid contact surfaces in complexes. In this work, we present a complete relaxation and conformational exchange matrix (CORCEMA) theory (H. N. B. Moseley et al., J. Magn. Reson. B 108, 243-261 (1995)) applicable for these two closely related experiments. As in our previous work, we show that when exchange is fast on the relaxation rate scale, a simplified CORCEMA theory can be formulated using a generalized average relaxation rate matrix. Its range of validity is established by comparing its predictions with those of the exact CORCEMA theory which is valid for all exchange rates. Using some ideal model systems we have analyzed the factors that influence the ligand proton intensity changes when the resonances from some protons on the receptor protein are saturated. The results show that the intensity changes in the ligand signals in an intermolecular NOE experiment are very much dependent upon: (1) the saturation time, (2) the location of the saturated receptor protons with respect to the ligand protons, (3) the conformation of the ligand-receptor interface, (4) the rotational correlation times for the molecular species, (5) the kinetics of the reversibly forming complex, and (6) the ligand/receptor ratio. As an example of a typical application of the STD-NMR experiment we have also simulated the STD effects for a

Spectroscopic study on the intermolecular interaction of SO{sub 2} absorption in poly-ethylene glycol+H{sub 2}O systems

Energy Technology Data Exchange (ETDEWEB)

He, Zhiqiang; Liu, Jinrong; Zhang, Jianbin; Zhang, Na [Inner Mongolia University of Technology, Huhhot (China)

2014-03-15

Poly-Ethylene Glycol (PEG) 300+H{sub 2}O solutions (PEGWs) has been used as a promising medium for the absorption of SO{sub 2}. We investigated the UV, FTIR, {sup 1}H-NMR, and fluorescence spectra in the absorption processes of SO{sub 2} in PEGWs to present an important absorption mechanism. Based on the spectral results, the possibility of intermolecular hydrogen bond formation by hydroxyl oxygen atom in the PEG molecule with hydrogen atom in H{sub 2}O and S…O interaction formation by the oxygen atoms in PEG with the sulfur atom in SO{sub 2} are discussed. This shows that the spectral changes may be due to the formation of -CH{sub 2}CH{sub 2}O(H)…HOH… and -CH{sub 2}-CH{sub 2}-O(CH{sub 2}-CH{sub 2}-)…HOH… in PEGWs and the formation of -CH{sub 2}CH{sub 2}OH…OSO…, and intermolecular S…O interaction between PEG and SO{sub 2} as the formation of -CH{sub 2}CH{sub 2}OCH{sub 2}CH{sub 2}O(H)…(O)S(O)… and -CH{sub 2}-CH{sub 2}-O(CH{sub 2}-CH{sub 2}-) …(O)S(O)…. The existence of these bonds benefits the absorption and desorption processes of SO{sub 2} in PEGWs.

Intra- versus Intermolecular Hydrogen Bonding: Solvent-Dependent Conformational Preferences of a Common Supramolecular Binding Motif from 1 H NMR and Vibrational Circular Dichroism Spectra.

Science.gov (United States)

Demarque, Daniel P; Merten, Christian

2017-12-19

When predicting binding properties of small molecules or larger supramolecular aggregates, intra- and intermolecular hydrogen bonds are often considered the most important factor. Spectroscopic techniques such as 1 H NMR spectroscopy are typically utilized to characterize such binding events, but interpretation is often qualitative and follows chemical intuition. In this study, we compare the effects of intramolecular hydrogen bonding and solvation on two chiral 2,6-pyridinediyl-dialkylamides. In comparison with 1 H NMR spectroscopy, vibrational circular dichroism (VCD) spectroscopy proved to be more sensitive to conformational changes. In fact, the change of the solvent from CDCl 3 to [D 6 ]DMSO generates mirror-image VCD spectra for the same enantiomer. Here, the common sense that the sterically less hindered group is more prone to solvation proved to be wrong according predicted VCD spectra, which clearly show that both asymmetric amide hydrogens are equally likely to be solvated, but never simultaneously. The competition between intra- and intermolecular hydrogen bonding and their importance for a correct prediction of spectral properties are discussed. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis and radioiodination of ergoline derivatives: potential in-vivo dopamine receptor site mapping radiopharmaceuticals

International Nuclear Information System (INIS)

Mikhail, E.A.

1985-01-01

The need of a dopamine-receptor based radiopharmaceutical for brain imaging is apparent. If such an agent is made available to physicians, it could provide means for detecting brain tumors, and diagnose such mental disorders as parkinsonism, schizophrenia and psychosis. Currently, such agents are yet to be discovered. Procedures were developed to synthesize and label four ergoline derivatives which could potentially exhibit affinity to dopamine receptors. Labelling with 125 I was accomplished in some cases by displacing a suitably positioned leaving group with 125 I-anion, while in other cases iodine exchange procedures were utilized. Formulations of the labeled derivatives were achieved via the formation of their water soluble tartarate salts. Biodistribution studies in mature Sprague-Dawley rats showed that of the four radioactive compounds injected, the highest uptake in the brain and adrenals was achieved with 8 β-[I-125]-iodomethyl-6-propylergoline. In addition, high target/nontarget ratios were obtained with the above mentioned compound. On the other hand, the least brain and adrenal uptake as well as the lowest target/nontarget ratios were exhibited by 8 β-[I-125]-(p-iodobenzenesulfonyl)-lysergol presumably due to its in-vivo instability. A comparative biodistribution study for ergoline derivatives and N-isopropyl-[I-123]-p-iodoamphetamine was conducted. The biodistribution studies showed that the brain to blood ratio for the ergoline derivative 8 β-[I-125]-iodomethyl-6-propylergoline to be very close to that for 125 I-IMP at 1 minute after dose administration. However after 15 minutes the brain/blood ratio of compound XLVI was half the value of 123 I-IMP. Different mechanisms of brain influx and efflux are known to occur with the amphetamine and ergoline derivatives

Rewetting phenomena and their relation to intermolecular forces between a hot wall and the fluid

International Nuclear Information System (INIS)

Gerweck, V.

1989-12-01

The rewetting phenomena and the different physical concepts which are used in their modelisation are reviewed. The present work studies the effect of the intermolecular forces between the hot wall and the fluid on this phase transition. Using suitable approximations, a local equation of state is obtained by the treatment of the fluid-fluid and fluid-wall intermolecular interactions. This local equation of state depends on the distance from the wall, and the critical pressure and temperature become a function of the distance from the wall, whereas the critical density is left constant throughout the fluid. At the wall, the critical pressure and temperature are half their bulk values and increase towards the bulk value as the distance from the wall increases. The penetration of a temperature profile in this fluid is studied by assuming that the liquid density is not strongly affected by this temperature profile as long as there is no phase transition. It is shown that the phase transition will occur extremely rapidly when the interfacial temperature upon contact is higher than the minimum of the local spinodal temperature, which varies with the distance from the wall. The result ist cast in the form of an interfacial rewetting temperature fT c above which rewetting of the surface by liquid-wall contacts is not expected because these contacts will be terminated in extremely short times. Comparing the theory with available data shows that in the usual rewetting situations the theory reduces to the use of the bulk spinodal temperature. For surfaces coated with poorly wetted materials the correction factor due to surface effects applies, reducing the rewetting temperature, in agreement with the experimental data. For liquid metals it appears that the theory is applied in a region where the basic theoretical approximations are very coarse; but even in that case the experimental trend is qualitatively predicted by the theory. (author) 43 figs., 11 tabs., 105 refs

Chondrogenic potential of bone marrow–derived mesenchymal stem cells on a novel, auricular-shaped, nanocomposite scaffold

Directory of Open Access Journals (Sweden)

Kavi H Patel

2013-12-01

Full Text Available Reconstruction of the human auricle remains a challenge to plastic surgeons, and current approaches are not ideal. Tissue engineering provides a promising alternative. This study aims to evaluate the chondrogenic potential of bone marrow–derived mesenchymal stem cells on a novel, auricular-shaped polymer. The proposed polyhedral oligomeric silsesquioxane-modified poly(hexanolactone/carbonateurethane/urea nanocomposite polymer has already been transplanted in patients as the world’s first synthetic trachea, tear duct and vascular bypass graft. The nanocomposite scaffold was fabricated via a coagulation/salt-leaching method and shaped into an auricle. Adult bone marrow–derived mesenchymal stem cells were isolated, cultured and seeded onto the scaffold. On day 21, samples were sent for scanning electron microscopy, histology and immunofluorescence to assess for neocartilage formation. Cell viability assay confirmed cytocompatability and normal patterns of cellular growth at 7, 14 and 21 days after culture. This study demonstrates the potential of a novel polyhedral oligomeric silsesquioxane-modified poly(hexanolactone/carbonateurethane/urea scaffold for culturing bone marrow–derived mesenchymal stem cells in chondrogenic medium to produce an auricular-shaped construct. This is supported by scanning electron microscopy, histological and immunofluorescence analysis revealing markers of chondrogenesis including collagen type II, SOX-9, glycosaminoglycan and elastin. To the best of our knowledge, this is the first report of stem cell application on an auricular-shaped scaffold for tissue engineering purposes. Although many obstacles remain in producing a functional auricle, this is a promising step forward.

Intermolecular interactions in aqueous solutions of gallic acid at 296-306 K according to spectrofluorimetry and densimetry data

Science.gov (United States)

Grigoryan, K. R.; Sargsyan, L. S.

2015-12-01

Features of intermolecular interactions in aqueous solutions of gallic acid (GA) are studied by means of densimetry and fluorescence spectroscopy (intrinsic fluorescence, 2D spectra, and excitation/ emission matrix fluorescence spectra, 3D) at 296.15, 301.15, and 306.15 K in the concentration range of 5.88 × 10-4-5.88 × 10-2 mol L-1. It is shown by analyzing the concentration and temperature dependences of the apparent molar volumes and fluorescence parameters of GA that the equilibrium between nonassociated and associated species in the solution and the hydration of these species undergo changes.

The therapeutic potential of plant-derived vaccines and antibodies.

Science.gov (United States)

Rodgers, P B; Hamilton, W D; Adair, J R

1999-03-01

The production of recombinant proteins in plants is reviewed with a particular focus on plant-derived vaccines and antibodies for human healthcare. Issues relating to foreign gene expression, such as protein yield, localisation and glycosylation are also considered. Emphasis is placed on reporting progress with preclinical and clinical evaluation of plant-derived vaccines and antibodies. An assessment is made of the likely future direction of research and development in this area.

Hypoxia Epigenetically Confers Astrocytic Differentiation Potential on Human Pluripotent Cell-Derived Neural Precursor Cells

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Tetsuro Yasui

2017-06-01

Full Text Available Human neural precursor cells (hNPCs derived from pluripotent stem cells display a high propensity for neuronal differentiation, but they require long-term culturing to differentiate efficiently into astrocytes. The mechanisms underlying this biased fate specification of hNPCs remain elusive. Here, we show that hypoxia confers astrocytic differentiation potential on hNPCs through epigenetic gene regulation, and that this was achieved by cooperation between hypoxia-inducible factor 1α and Notch signaling, accompanied by a reduction of DNA methylation level in the promoter region of a typical astrocyte-specific gene, Glial fibrillary acidic protein. Furthermore, we found that this hypoxic culture condition could be applied to rapid generation of astrocytes from Rett syndrome patient-derived hNPCs, and that these astrocytes impaired neuronal development. Thus, our findings shed further light on the molecular mechanisms regulating hNPC differentiation and provide attractive tools for the development of therapeutic strategies for treating astrocyte-mediated neurological disorders.

Substance P enhances proliferation and paracrine potential of adipose-derived stem cells in vitro

International Nuclear Information System (INIS)

Kim, Suna; Piao, Jiyuan; Son, Youngsook; Hong, Hyun Sook

2017-01-01

Stem cells have tremendous promise to treat intractable diseases. Notably, adipose-derived stem cells (ADSCs) are actively being investigated because of ease of sampling and high repopulation capacity in vitro. ADSCs can exert a therapeutic effect through differentiation and paracrine potential, and these actions have been proven in many diseases, including cutaneous and inflammatory diseases. Transplantation of ADSCs necessitates therapeutic quantities and thus, long term ex vivo culture of ADSCs. However, this procedure can impair the activity of ADSCs and provoke cellular senescence, leading to low efficacy in vivo. Accordingly, strategies to restore cellular activity and inhibit senescence of stem cells during ex vivo culture are needed for stem cell-based therapies. This study evaluated a potential supplementary role of Substance P (SP) in ADSC ex vivo culture. After confirming that the ADSC cell cycle was damaged by passage 6 (p6), ADSCs at p6 were cultured with SP, and their proliferation rates, cumulative cell numbers, cytokine profiles, and impact on T/endothelial cells were assessed. Long-term culture weakened proliferation ability and secretion of the cytokines, transforming growth factor-beta 1 (TGF-beta1), vascular endothelial growth factor (VEGF), and stromal cell derived factor-1 alpha (SDF-1alpha) in ADSCs. However, SP treatment reduced the population doubling time (PDT), enabling gain of a sufficient number of ADSCs at early passages. In addition, SP restored cytokine secretion, enhancing the ADSC-mediated paracrine effect on T cell and human umbilical vein endothelial cells (HUVECs). Taken together, these results suggest that SP can retain the therapeutic effect of ADSCs by elevating their proliferative and paracrine potential in ex vivo culture. - Highlights: • Long-term culture of ADSCs leads to cell senescence. • Paracrine potential of ADSC decreases as passage number increases. • SP enhances the weakened proliferation capacity of

Effects of Weak Intermolecular Interactions on the Molecular Isomerism of Tricobalt Metal Chains

International Nuclear Information System (INIS)

Poulsen, R.; Overgaard, J.; Schulman, A.; Stergaard, C.; Murillo, C.; Spackman, M.; Iversen, B.

2009-01-01

Depending on the number of interstitial solvent molecules, n, crystals of the linear chain compound Co3(dipyridylamide)4Cl2·nCH2Cl2 adopt either symmetrical or unsymmetrical metal chain structures. We explore here the possible reasons for such behavior using Hirshfeld surface analysis of intermolecular interactions as well as the charge density determined from 100(1) K X-ray diffraction data on the unsymmetrical complex Co3(dipyridylamide)4Cl2·2.11CH2Cl2, u-1, and crystal structures of u-1 determined from single crystal synchrotron X-ray diffraction data at 20, 150, and 300 K. The new crystal structures are compared with previous structural results on a crystal with slightly different solvent content. This change in solvent content only affects the bond distances to atom Co(3), which are also strongly affected by temperature changes due to a spin crossover transition. Large differences in intermolecular interactions are revealed by the Hirshfeld surface analysis between symmetrical (s-1) and unsymmetrical (u-1) crystal solvates, suggesting that the molecular isomerism is strongly influenced by crystal packing effects. Topological analysis of the static electron density of u-1 suggests that there is direct metal-metal bonding for both the shorter Co(1)-Co(2) and the longer Co(2)-Co(3) contact. The approximate description of the system as a (Co2)2+-dimer and an isolated Co2+-ion is reflected in the character of the metal-ligand interactions, which are more ionic for the isolated Co(3) atom, and the topological charges Co(1)+0.50, Co(2)+0.77, and Co(3)+1.36. The two termini of u-1 are found to be very different, both in terms of structural surroundings as well as topology. The central Co(2) atom is similar to a cobalt atom in a tetragonally distorted octahedral environment resulting in preferred occupancy in the t2g orbitals. The Co(1) atom has significant deformation in the xz and yz planes (z along the chain axis, x and y toward ligands) reflecting covalent

Evaluation of 18F-labeled icotinib derivatives as potential PET agents for tumor imaging

International Nuclear Information System (INIS)

Hongyu Ren; Hongyu Ning; Jin Chang; Mingxia Zhao; Yong He; Yan Chong; Chuanmin Qi

2016-01-01

In this study, three 18 F-labeled crown ether fused anilinoquinazoline derivatives ([ 18 F]11a-c) were synthesized and evaluated as potential tumor imaging probes. The biodistribution results of [ 18 F]11b were good. Compared with [ 18 F]-fludeoxyglucose and l-[ 18 F]-fluoroethyltyrosine in the same animal model, [ 18 F]11b had better tumor/brain, tumor/muscle, and tumor/blood uptake ratios. Overall, these results suggest that [ 18 F]11b is promising as a tumor imaging agent for positron emission tomography. (author)

Preparation of new boron compounds with potential for application in 10B NCT: Derivatives of monocarbon carboranes

International Nuclear Information System (INIS)

Morris, J.H.; Khan, S.A.; Mair, F.; Peters, G.

1992-01-01

In order to extend the range and versatility of boron clusters appropriate to NCT the authors have studied routes to derivatives of the anions 1-carba-closo-dodecahydrododecaborate-1, [CB 11 H 12 ] - , (1), and its synthetic precursor, 7-carba-nido-tridecahydroundecaborate-1, [CB 10 H 13 ] - , (2). Substitution chemistry of closo-[CB 11 H 12 ] - and its derivatives had been examined previously primarily with respect to substituents at the C-atom. The different isomeric sites of boron substitution, which have been much less studied, offer potential scope for subtle modification of properties of the substituted species. They have sought to prepare thiol substituted derivatives analogous to the widely studied species [B 12 H 11 SH] 2- . The preliminary experiments to introduce the thiol substituent by routes analogous to those for the preparation of [B 12 H 11 SH] 2- or 1- and 2-[B 10 H 9 SH] 2- were unsuccessful. Therefore they considered routes involving prior substitution of either the precursor nido-[CB 10 H 13 ] - and its derivatives, or the monoboron species used for boron insertion

Relativistic effects in the intermolecular interaction-induced nuclear magnetic resonance parameters of xenon dimer

DEFF Research Database (Denmark)

Hanni, Matti; Lantto, Perttu; Ilias, Miroslav

2007-01-01

Relativistic effects on the 129Xe nuclear magnetic resonance shielding and 131Xe nuclear quadrupole coupling (NQC) tensors are examined in the weakly bound Xe2 system at different levels of theory including the relativistic four-component Dirac-Hartree-Fock (DHF) method. The intermolecular...... interaction-induced binary chemical shift d, the anisotropy of the shielding tensor ?s, and the NQC constant along the internuclear axis ?ll are calculated as a function of the internuclear distance. DHF shielding calculations are carried out using gauge-including atomic orbitals. For comparison, the full...... is obtained for d and ?s in Xe2. For these properties, the currently most complete theoretical description is obtained by a piecewise approximation where the uncorrelated relativistic DHF results obtained close to the basis-set limit are corrected, on the one hand, for NR correlation effects and, on the other...

ECM microenvironment unlocks brown adipogenic potential of adult human bone marrow-derived MSCs.

Science.gov (United States)

Lee, Michelle H; Goralczyk, Anna G; Kriszt, Rókus; Ang, Xiu Min; Badowski, Cedric; Li, Ying; Summers, Scott A; Toh, Sue-Anne; Yassin, M Shabeer; Shabbir, Asim; Sheppard, Allan; Raghunath, Michael

2016-02-17

Key to realizing the diagnostic and therapeutic potential of human brown/brite adipocytes is the identification of a renewable, easily accessible and safe tissue source of progenitor cells, and an efficacious in vitro differentiation protocol. We show that macromolecular crowding (MMC) facilitates brown adipocyte differentiation in adult human bone marrow mesenchymal stem cells (bmMSCs), as evidenced by substantially upregulating uncoupling protein 1 (UCP1) and uncoupled respiration. Moreover, MMC also induced 'browning' in bmMSC-derived white adipocytes. Mechanistically, MMC creates a 3D extracellular matrix architecture enshrouding maturing adipocytes in a collagen IV cocoon that is engaged by paxillin-positive focal adhesions also at the apical side of cells, without contact to the stiff support structure. This leads to an enhanced matrix-cell signaling, reflected by increased phosphorylation of ATF2, a key transcription factor in UCP1 regulation. Thus, tuning the dimensionality of the microenvironment in vitro can unlock a strong brown potential dormant in bone marrow.

Assessment of some straw-derived materials for reducing the leaching potential of Metribuzin residues in the soil

Energy Technology Data Exchange (ETDEWEB)

Cara, Irina Gabriela, E-mail: coroirina@yahoo.com [“Ion Ionescu de la Brad” University of Agricultural Sciences and Veterinary Medicine, Faculty of Agriculture, 3M. Sadoveanu Alley, 700490 Iasi (Romania); Trincă, Lucia Carmen, E-mail: lctrinca@uaiasi.ro [“Ion Ionescu de la Brad” University of Agricultural Sciences and Veterinary Medicine, Faculty of Horticulture, 3 M. Sadoveanu Alley, 700490 Iasi (Romania); Trofin, Alina Elena, E-mail: aetrofin@yahoo.com [“Ion Ionescu de la Brad” University of Agricultural Sciences and Veterinary Medicine, Faculty of Horticulture, 3 M. Sadoveanu Alley, 700490 Iasi (Romania); Cazacu, Ana, E-mail: anagarlea@gmail.com [“Ion Ionescu de la Brad” University of Agricultural Sciences and Veterinary Medicine, Faculty of Horticulture, 3 M. Sadoveanu Alley, 700490 Iasi (Romania); Ţopa, Denis, E-mail: topadennis@yahoo.com [“Ion Ionescu de la Brad” University of Agricultural Sciences and Veterinary Medicine, Faculty of Agriculture, 3M. Sadoveanu Alley, 700490 Iasi (Romania); Peptu, Cătălina Anişoara, E-mail: catipeptu@yahoo.co.uk [“Gheorghe Asachi” Technical University of Iasi, Faculty of Chemical Engineering and Environmental Protection, 73 D. Mangeron Street, 700050 Iasi (Romania); Jităreanu, Gerard, E-mail: gerardj@uaiasi.ro [“Ion Ionescu de la Brad” University of Agricultural Sciences and Veterinary Medicine, Faculty of Agriculture, 3M. Sadoveanu Alley, 700490 Iasi (Romania)

2015-12-15

Highlights: • Surface characteristics of activated straw (wheat, corn, soybean) were assessed. • Modification methods to enhance materials sorption were presented. • Adsorption mechanism of metribuzin was revealed and discussed. - Abstract: Biomass (straw waste) can be used as raw to obtain materials for herbicide removal from wastewater. These by-products have some important advantages, being environmentally friendly, easily available, presenting low costs, and requiring little processing to increase their adsorptive capacity. In the present study, some materials derived from agricultural waste (wheat, corn and soybean straw) were investigated as potential adsorbents for metribuzin removal from aqueous solutions. The straw wastes were processed by grinding, mineralisation (850 °C) and KOH activation in order to improve their functional surface activity. The materials surface characteristics were investigated by scanning electron microscopy, energy dispersive X-ray spectroscopy and atomic force microscopy. The adsorbents capacity was evaluated using batch sorption tests and liquid chromatography coupled with mass spectrometry for herbicide determination. For adsorption isotherms, the equilibrium time considered was 3 h. The experimental adsorption data were modelled by Freundlich and Langmuir models. The activated straw and ash-derived materials from wheat, corn and soybean increased the adsorption capacity of metribuzin with an asymmetrical behaviour. Overall, our results sustain that activated ash-derived from straw and activated straw materials can be a valuable solution for reducing the leaching potential of metribuzin through soil.

Assessment of some straw-derived materials for reducing the leaching potential of Metribuzin residues in the soil

International Nuclear Information System (INIS)

Cara, Irina Gabriela; Trincă, Lucia Carmen; Trofin, Alina Elena; Cazacu, Ana; Ţopa, Denis; Peptu, Cătălina Anişoara; Jităreanu, Gerard

2015-01-01

Highlights: • Surface characteristics of activated straw (wheat, corn, soybean) were assessed. • Modification methods to enhance materials sorption were presented. • Adsorption mechanism of metribuzin was revealed and discussed. - Abstract: Biomass (straw waste) can be used as raw to obtain materials for herbicide removal from wastewater. These by-products have some important advantages, being environmentally friendly, easily available, presenting low costs, and requiring little processing to increase their adsorptive capacity. In the present study, some materials derived from agricultural waste (wheat, corn and soybean straw) were investigated as potential adsorbents for metribuzin removal from aqueous solutions. The straw wastes were processed by grinding, mineralisation (850 °C) and KOH activation in order to improve their functional surface activity. The materials surface characteristics were investigated by scanning electron microscopy, energy dispersive X-ray spectroscopy and atomic force microscopy. The adsorbents capacity was evaluated using batch sorption tests and liquid chromatography coupled with mass spectrometry for herbicide determination. For adsorption isotherms, the equilibrium time considered was 3 h. The experimental adsorption data were modelled by Freundlich and Langmuir models. The activated straw and ash-derived materials from wheat, corn and soybean increased the adsorption capacity of metribuzin with an asymmetrical behaviour. Overall, our results sustain that activated ash-derived from straw and activated straw materials can be a valuable solution for reducing the leaching potential of metribuzin through soil.

Derivation of a configuration space Hamiltonian for heavy atoms: three body potentials

International Nuclear Information System (INIS)

Mittleman, M.H.

1981-01-01

A brief history of the difficulties associated with the derivation of a configuration space Hamiltonian is presented. One of the problems encountered is the definition of the projection operators which must occur. A variational definition is obtained and, with simplifying assumptions, the optimum projection operators are those which project onto Hartree-Fock orbitals. This puts many previously performed numerical calculations on a firm footing. The form of the two body interactions is discussed in the context of the gauge freedom. The Coulomb gauge is the favored one but it is pointed out that it has never been proven to be the best one. Finally a form for the relativistic three election potential is given and the possibility of its observation is discussed

Natural Product-Derived Treatments for Attention-Deficit/Hyperactivity Disorder: Safety, Efficacy, and Therapeutic Potential of Combination Therapy

Science.gov (United States)

Ahn, James; Ahn, Hyung Seok; Cheong, Jae Hoon; dela Peña, Ike

2016-01-01

Typical treatment plans for attention-deficit/hyperactivity disorder (ADHD) utilize nonpharmacological (behavioral/psychosocial) and/or pharmacological interventions. Limited accessibility to behavioral therapies and concerns over adverse effects of pharmacological treatments prompted research for alternative ADHD therapies such as natural product-derived treatments and nutritional supplements. In this study, we reviewed the herbal preparations and nutritional supplements evaluated in clinical studies as potential ADHD treatments and discussed their performance with regard to safety and efficacy in clinical trials. We also discussed some evidence suggesting that adjunct treatment of these agents (with another botanical agent or pharmacological ADHD treatments) may be a promising approach to treat ADHD. The analysis indicated mixed findings with regard to efficacy of natural product-derived ADHD interventions. Nevertheless, these treatments were considered as a “safer” approach than conventional ADHD medications. More comprehensive and appropriately controlled clinical studies are required to fully ascertain efficacy and safety of natural product-derived ADHD treatments. Studies that replicate encouraging findings on the efficacy of combining botanical agents and nutritional supplements with other natural product-derived therapies and widely used ADHD medications are also warranted. In conclusion, the risk-benefit balance of natural product-derived ADHD treatments should be carefully monitored when used as standalone treatment or when combined with other conventional ADHD treatments. PMID:26966583

Different Angiogenic Potentials of Mesenchymal Stem Cells Derived from Umbilical Artery, Umbilical Vein, and Wharton’s Jelly

Directory of Open Access Journals (Sweden)

Lu Xu

2017-01-01

Full Text Available Human mesenchymal stem cells derived from the umbilical cord (UC are a favorable source for allogeneic cell therapy. Here, we successfully isolated the stem cells derived from three different compartments of the human UC, including perivascular stem cells derived from umbilical arteries (UCA-PSCs, perivascular stem cells derived from umbilical vein (UCV-PSCs, and mesenchymal stem cells derived from Wharton’s jelly (WJ-MSCs. These cells had the similar phenotype and differentiation potential toward adipocytes, osteoblasts, and neuron-like cells. However, UCA-PSCs and UCV-PSCs had more CD146+ cells than WJ-MSCs (P<0.05. Tube formation assay in vitro showed the largest number of tube-like structures and branch points in UCA-PSCs among the three stem cells. Additionally, the total tube length in UCA-PSCs and UCV-PSCs was significantly longer than in WJ-MSCs (P<0.01. Microarray, qRT-PCR, and Western blot analysis showed that UCA-PSCs had the highest expression of the Notch ligand Jagged1 (JAG1, which is crucial for blood vessel maturation. Knockdown of Jagged1 significantly impaired the angiogenesis in UCA-PSCs. In summary, UCA-PSCs are promising cell populations for clinical use in ischemic diseases.

Bimolecular Master Equations for a Single and Multiple Potential Wells with Analytic Solutions.

Science.gov (United States)

Ghaderi, Nima

2018-04-12

The analytic solutions, that is, populations, are derived for the K-adiabatic and K-active bimolecular master equations, separately, for a single and multiple potential wells and reaction channels, where K is the component of the total angular momentum J along the axis of least moment of inertia of the recombination products at a given energy E. The analytic approach provides the functional dependence of the population of molecules on its K-active or K-adiabatic dissociation, association rate constants and the intermolecular energy transfer, where the approach may complement the usual numerical approaches for reactions of interest. Our previous work, Part I, considered the solutions for a single potential well, whereby an assumption utilized there is presently obviated in the derivation of the exact solutions and farther discussed. At the high-pressure limit, the K-adiabatic and K-active bimolecular master equations may each reduce, respectively, to the K-adiabatic and K-active bimolecular Rice-Ramsperger-Kassel-Marcus theory (high-pressure limit expressions) for bimolecular recombination rate constant, for a single potential well, and augmented by isomerization terms when multiple potential wells are present. In the low-pressure limit, the expression for population above the dissociation limit, associated with a single potential well, becomes equivalent to the usual presumed detailed balance between the association and dissociation rate constants, where the multiple well case is also considered. When the collision frequency of energy transfer, Z LJ , between the chemical intermediate and bath gas is sufficiently less than the dissociation rate constant k d ( E' J' K') for postcollision ( E' J' K), then the solution for population, g( EJK) + , above the critical energy further simplifies such that depending on Z LJ , the dissociation and association rate constant k r ( EJK), as g( EJK) + = k r ( EJK)A·BC/[ Z LJ + k d ( EJK)], where A and BC are the reactants, for

Crystal structures of 4-chloropyridine-2-carbonitrile and 6-chloropyridine-2-carbonitrile exhibit different intermolecular π-stacking, C—H...Nnitrile and C—H...Npyridine interactions

Directory of Open Access Journals (Sweden)

Matthew J. Montgomery

2015-07-01

Full Text Available The two title compounds are isomers of C6H3ClN2 containing a pyridine ring, a nitrile group, and a chloro substituent. The molecules of each compound pack together in the solid state with offset face-to-face π-stacking, and intermolecular C—H...Nnitrile and C—H...Npyridine interactions. 4-Chloropyridine-2-carbonitrile, (I, exhibits pairwise centrosymmetric head-to-head C—H...Nnitrile and C—H...Npyridine interactions, forming one-dimensional chains, which are π-stacked in an offset face-to-face fashion. The intermolecular packing of the isomeric 6-chloropyridine-2-carbonitrile, (II, which differs only in the position of the chloro substituent on the pyridine ring, exhibits head-to-tail C—H...Nnitrile and C—H...Npyridine interactions, forming two-dimensional sheets which are π-stacked in an offset face-to-face fashion. In contrast to (I, the offset face-to-face π-stacking in (II is formed between molecules with alternating orientations of the chloro and nitrile substituents.

Algorithms for Computing the Magnetic Field, Vector Potential, and Field Derivatives for Circular Current Loops in Cylindrical Coordinates

Energy Technology Data Exchange (ETDEWEB)

Walstrom, Peter Lowell [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-08-24

A numerical algorithm for computing the field components B_r and B_z and their r and z derivatives with open boundaries in cylindrical coordinates for circular current loops is described. An algorithm for computing the vector potential is also described. For the convenience of the reader, derivations of the final expressions from their defining integrals are given in detail, since their derivations (especially for the field derivatives) are not all easily found in textbooks. Numerical calculations are based on evaluation of complete elliptic integrals using the Bulirsch algorithm cel. Since cel can evaluate complete elliptic integrals of a fairly general type, in some cases the elliptic integrals can be evaluated without first reducing them to forms containing standard Legendre forms. The algorithms avoid the numerical difficulties that many of the textbook solutions have for points near the axis because of explicit factors of 1=r or 1=r² in the some of the expressions.

The differentiation potential of adipose tissue-derived mesenchymal stem cells into cell lineage related to male germ cells

Directory of Open Access Journals (Sweden)

P. Bräunig

Full Text Available ABSTRACT The adipose tissue is a reliable source of Mesenchymal stem cells (MSCs showing a higher plasticity and transdifferentiation potential into multilineage cells. In the present study, adipose tissue-derived mesenchymal stem cells (AT-MSCs were isolated from mice omentum and epididymis fat depots. The AT-MSCs were initially compared based on stem cell surface markers and on the mesodermal trilineage differentiation potential. Additionally, AT-MSCs, from both sources, were cultured with differentiation media containing retinoic acid (RA and/or testicular cell-conditioned medium (TCC. The AT-MSCs expressed mesenchymal surface markers and differentiated into adipogenic, chondrogenic and osteogenic lineages. Only omentum-derived AT-MSCs expressed one important gene marker related to male germ cell lineages, after the differentiation treatment with RA. These findings reaffirm the importance of adipose tissue as a source of multipotent stromal-stem cells, as well as, MSCs source regarding differentiation purpose.

Preferential Redistribution of Fine-Grained Particles in the Panama Basin and Potential Errors in 230Th-Derived Focusing Factors

Science.gov (United States)

Marcantonio, F.; Lyle, M. W.; Ibrahim, R.

2013-12-01

The 230Th constant-flux proxy technique, commonly used in paleoceanography to estimate sediment fluxes, is thought to differentiate lateral from vertical fluxes of sediment at sites that have undergone sediment redistribution. However, redistribution processes (focusing or winnowing) are expected to fractionate fine particles from those that are coarse. Since fine particles with greater surface area are known to contain greater concentrations of 230Th, one might expect that sediment redistribution would bias 230Th-derived sediment mass accumulation rates (MARs). We investigate this possibility in two regions of the Panama Basin where significant sediment focusing has been hypothesized to occur. We examine multicore sediments from paired sites at two locations, one close to the equator at the southern limit of the Panama Basin (Carnegie Ridge) where upwelling and primary productivity are high, and one at 6°N at the northern boundary of the Panama Basin (Cocos Ridge), where primary productivity is lower. The multicores, which are constrained by radiocarbon ages that span the latest Holocene at each paired site, represent regions that have undergone potential winnowing and focusing (thin vs thick sediment drapes identified using seismic reflection) at each Panama Basin location. Since the distance separating the paired sites at each location is no more than about 50 km, one would expect the 230Th-derived MARs to be similar, i.e., the rain rate should not be significantly different at each of the paired sites. The radiocarbon-derived sand fraction (>63-μm) MARs, which likely represent the vertical rain of particles not transported by bottom currents, are identical at each of the paired sites, with fluxes at the Carnegie Ridge about 3.5 times greater than those at the Cocos Ridge over the past several thousand years. Over the same time period, the 230Th-normalized MARs are relatively similar at both the Carnegie and Cocos sites, but are different by about 60% at each

The Potential Biomarkers and Immunological Effects of Tumor-Derived Exosomes in Lung Cancer

Directory of Open Access Journals (Sweden)

Shamila D. Alipoor

2018-04-01

Full Text Available Lung cancer remains the leading cause of cancer-related deaths worldwide. Despite considerable achievements in lung cancer diagnosis and treatment, the global control of the disease remains problematic. In this respect, greater understanding of the disease pathology is crucially needed for earlier diagnosis and more successful treatment to be achieved. Exosomes are nano-sized particles secreted from most cells, which allow cross talk between cells and their surrounding environment via transferring their cargo. Tumor cells, just like normal cells, also secrete exosomes that are termed Tumor-Derived Exosome or tumor-derived exosome (TEX. TEXs have gained attention for their immuno-modulatory activities, which strongly affect the tumor microenvironment and antitumor immune responses. The immunological activity of TEX influences both the innate and adaptive immune systems including natural killer cell activity and regulatory T-cell maturation as well as numerous anti-inflammatory responses. In the context of lung cancer, TEXs have been studied in order to better understand the mechanisms underlying tumor metastasis and progression. As such, TEX has the potential to act both as a biomarker for lung cancer diagnosis as well as the response to therapy.

Influence of intermolecular amide hydrogen bonding on the geometry, atomic charges, and spectral modes of acetanilide: An ab initio study

Science.gov (United States)

Binoy, J.; Prathima, N. B.; Murali Krishna, C.; Santhosh, C.; Hubert Joe, I.; Jayakumar, V. S.

2006-08-01

Acetanilide, a compound of pharmaceutical importance possessing pain-relieving properties due to its blocking the pulse dissipating along the nerve fiber, is subjected to vibrational spectral investigation using NIR FT Raman, FT-IR, and SERS. The geometry, Mulliken charges, and vibrational spectrum of acetanilide have been computed using the Hartree-Fock theory and density functional theory employing the 6-31G (d) basis set. To investigate the influence of intermolecular amide hydrogen bonding, the geometry, charge distribution, and vibrational spectrum of the acetanilide dimer have been computed at the HF/6-31G (d) level. The computed geometries reveal that the acetanilide molecule is planar, while twisting of the secondary amide group with respect to the phenyl ring is found upon hydrogen bonding. The trans isomerism and “amido” form of the secondary amide, hyperconjugation of the C=O group with the adjacent C-C bond, and donor-acceptor interaction have been investigated using computed geometry. The carbonyl stretching band position is found to be influenced by the tendency of the phenyl ring to withdraw nitrogen lone pair, intermolecular hydrogen bonding, conjugation, and hyperconjugation. A decrease in the NH and C=O bond orders and increase in the C-N bond orders due to donor-acceptor interaction can be observed in the vibrational spectra. The SERS spectral analysis reveals that the flat orientation of the molecule on the adsorption plane is preferred.

The potential of tumor-derived exosomes for noninvasive cancer monitoring.

Science.gov (United States)

Whiteside, Theresa L

2015-01-01

Tumor-derived exosomes (TEX) are emerging as a new type of cancer biomarker. TEX are membrane-bound, virus-size vesicles of endocytic origin present in all body fluids of cancer patients. Based on the expanding albeit incomplete knowledge of their biogenesis, secretion by tumor cells and cancer cell-specific molecular and genetic contents, TEX are viewed as promising, clinically-relevant surrogates of cancer progression and response to therapy. Preliminary proteomic, genetic and functional profiling of tumor cell-derived or cancer plasma-derived exosomes confirms their unique characteristics. Alterations in protein or nucleic acid profiles of exosomes in plasma of cancer patients responding to therapies appear to correlate with clinical endpoints. However, methods for TEX isolation and separation from the bulk of human plasma-derived exosomes are not yet established and their role as biomarkers remains to be confirmed. Further development and validation of TEX as noninvasive, liquid equivalents of tumor biopsies are necessary to move this effort forward.

Assessment of the Bacteriocinogenic Potential of Marine Bacteria Reveals Lichenicidin Production by Seaweed-Derived Bacillus spp.

Directory of Open Access Journals (Sweden)

Gillian E. Gardiner

2012-10-01

Full Text Available The objectives of this study were (1 to assess the bacteriocinogenic potential of bacteria derived mainly from seaweed, but also sand and seawater, (2 to identify at least some of the bacteriocins produced, if any and (3 to determine if they are unique to the marine environment and/or novel. Fifteen Bacillus licheniformis or pumilus isolates with antimicrobial activity against at least one of the indicator bacteria used were recovered. Some, at least, of the antimicrobials produced were bacteriocins, as they were proteinaceous and the producers displayed immunity. Screening with PCR primers for known Bacillus bacteriocins revealed that three seaweed-derived Bacillus licheniformis harbored the bli04127 gene which encodes one of the peptides of the two-peptide lantibiotic lichenicidin. Production of both lichenicidin peptides was then confirmed by mass spectrometry. This is the first definitive proof of bacteriocin production by seaweed-derived bacteria. The authors acknowledge that the bacteriocin produced has previously been discovered and is not unique to the marine environment. However, the other marine isolates likely produce novel bacteriocins, as none harboured genes for known Bacillus bacteriocins.

Modeling the intermolecular interactions: molecular structure of N-3-hydroxyphenyl-4-methoxybenzamide.

Science.gov (United States)

Karabulut, Sedat; Namli, Hilmi; Kurtaran, Raif; Yildirim, Leyla Tatar; Leszczynski, Jerzy

2014-03-01

The title compound, N-3-hydroxyphenyl-4-methoxybenzamide (3) was prepared by the acylation reaction of 3-aminophenol (1) and 4-metoxybenzoylchloride (2) in THF and characterized by ¹H NMR, ¹³C NMR and elemental analysis. Molecular structure of the crystal was determined by single crystal X-ray diffraction and DFT calculations. 3 crystallizes in monoclinic P2₁/c space group. The influence of intermolecular interactions (dimerization and crystal packing) on molecular geometry has been evaluated by calculations performed for three different models; monomer (3), dimer (4) and dimer with added unit cell contacts (5). Molecular structure of 3, 4 and 5 was optimized by applying B3LYP method with 6-31G+(d,p) basis set in gas phase and compared with X-ray crystallographic data including bond lengths, bond angles and selected dihedral angles. It has been concluded that although the crystal packing and dimerization have a minor effect on bond lengths and angles, however, these interactions are important for the dihedral angles and the rotational conformation of aromatic rings. Copyright © 2013 Elsevier Inc. All rights reserved.

Second vertical derivative of potential fields using an adaptation of ...

African Journals Online (AJOL)

The second vertical derivative of magnetic fields is commonly used for resolution of anomalies in gravity and magnetic fields. It is also commonly used as an aid to geologic mapping i.e. for the delineation of geological discontinuities in the subsurface. Frequency domain methods for calculating second vertical derivatives ...

Synthesis and Electrochemical Study of a TCAA Derivative – A potential bipolar redox-active material

International Nuclear Information System (INIS)

Hagemann, Tino; Winsberg, Jan; Wild, Andreas; Schubert, Ulrich S.

2017-01-01

The 2,3,7,8-tetracyano-1,4,5,6,9,10-hexazaanthracene (TCAA) derivatives represent an interesting substance class for future research on organic electronic devices, such as solar cells, organic batteries or redox-flow batteries (RFBs). Because of their multivalent redox behavior they are potentially “bipolar”, usable both as cathode and anode activ charge-storage materials. Furthermore, they show a strong absorption and fluorescence behavior both in solution and solid state, rendering them a promising emitter for electroluminescence devices, like lamps or displays. In order to evaluate a TCAA for electrochemical applications the derivative 2,3,7,8-tetracyano-5,10-diphenyl-5,10-dihydrodipyrazino[2,3-b:2′,3′-e] pyrazine (2) was synthesized in two straightforward synthesis steps. The electrochemical behavior of 2 was initially determined by density functional theory (DFT) calculation and afterwards investigated via rotating disc electrode (RDE), UV–vis–NIR spectroelectrochemical as well as cyclic voltammetry (CV) measurements. It features a quasi-reversible oxidation and re-reduction at E ½ = 1.42 V vs. Fc + /Fc with a peak split of 96 mV and a quasi-reversible reduction and re-oxidation at E ½ = −1.49 V vs. Fc + /Fc with a peak split of 174 mV, which lead to a theoretical potential difference of 2.91 V.

Hyaluronan preserves the proliferation and differentiation potentials of long-term cultured murine adipose-derived stromal cells

International Nuclear Information System (INIS)

Chen, P.-Y.; Huang, Lynn L.H.; Hsieh, H.-J.

2007-01-01

For long-term culture, murine adipose-derived stromal cells (mADSCs) at latter passages demonstrated a marked decline in proliferative activity, exhibited senescent morphology and reduced differentiation potentials, particularly osteogenesis. To extend the lifespan of mADSCs, two culture conditions containing hyaluronan (HA) was compared in our study, one as a culture medium supplement (SHA), and the other where HA was pre-coated on culture surface (CHA). mADSCs cultivated with SHA exhibited a prolonged lifespan, reduced cellular senescence, and enhanced osteogenic potential compared to regular culture condition (control). Upon CHA treatment, mADSCs tended to form cell aggregates with gradual growth profiles, while their differentiation activities remained similar to SHA groups. After transferring mADSCs from CHA to control surface, they were shown to have an extended lifespan and an increase of osteogenic potential. Our results suggested that HA can be useful for preserving the proliferation and differentiation potentials of long-term cultured mADSCs

Value-added potential of expeller-pressed canola oil refining: characterization of sinapic acid derivatives and tocopherols from byproducts.

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Chen, Yougui; Thiyam-Hollander, Usha; Barthet, Veronique J; Aachary, Ayyappan A

2014-10-08

Valuable phenolic antioxidants are lost during oil refining, but evaluation of their occurrence in refining byproducts is lacking. Rapeseed and canola oil are both rich sources of sinapic acid derivatives and tocopherols. The retention and loss of sinapic acid derivatives and tocopherols in commercially produced expeller-pressed canola oils subjected to various refining steps and the respective byproducts were investigated. Loss of canolol (3) and tocopherols were observed during bleaching (84.9%) and deodorization (37.6%), respectively. Sinapic acid (2) (42.9 μg/g), sinapine (1) (199 μg/g), and canolol (344 μg/g) were found in the refining byproducts, namely, soap stock, spent bleaching clay, and wash water, for the first time. Tocopherols (3.75 mg/g) and other nonidentified phenolic compounds (2.7 mg sinapic acid equivalent/g) were found in deodistillates, a byproduct of deodorization. DPPH radical scavenging confirmed the antioxidant potential of the byproducts. This study confirms the value-added potential of byproducts of refining as sources of endogenous phenolics.

Evaluation of substituted ebselen derivatives as potential trypanocidal agents.

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Gordhan, Heeren M; Patrick, Stephen L; Swasy, Maria I; Hackler, Amber L; Anayee, Mark; Golden, Jennifer E; Morris, James C; Whitehead, Daniel C

2017-02-01

Human African trypanosomiasis is a disease of sub-Saharan Africa, where millions are at risk for the illness. The disease, commonly referred to as African sleeping sickness, is caused by an infection by the eukaryotic pathogen, Trypanosoma brucei. Previously, a target-based high throughput screen revealed ebselen (EbSe), and its sulfur analog, EbS, to be potent in vitro inhibitors of the T. brucei hexokinase 1 (TbHK1). These molecules also exhibited potent trypanocidal activity in vivo. In this manuscript, we synthesized a series of sixteen EbSe and EbS derivatives bearing electron-withdrawing carboxylic acid and methyl ester functional groups, and evaluated the influence of these substituents on the biological efficacy of the parent scaffold. With the exception of one methyl ester derivative, these modifications ablated or blunted the potent TbHK1 inhibition of the parent scaffold. Nonetheless, a few of the methyl ester derivatives still exhibited trypanocidal effects with single-digit micromolar or high nanomolar EC 50 values. Copyright © 2016 Elsevier Ltd. All rights reserved.

Withanolides derived from Physalis peruviana (Poha) with potential anti-inflammatory activity.

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Sang-Ngern, Mayuramas; Youn, Ui Joung; Park, Eun-Jung; Kondratyuk, Tamara P; Simmons, Charles J; Wall, Marisa M; Ruf, Michael; Lorch, Sam E; Leong, Ethyn; Pezzuto, John M; Chang, Leng Chee

2016-06-15

Three new withanolides, physaperuvin G (1), with physaperuvins I (2), and J (3), along with seven known derivatives (4-10), were isolated from the aerial parts of Physalis peruviana. The structures of 1-3 were determined by NMR, X-ray diffraction, and mass spectrometry. Compounds 1-10 were evaluated in lipopolysaccharide (LPS)-activated murine macrophage RAW 264.7 cells. Compounds 4, 5, and 10 with potent nitric oxide inhibitory activity in LPS-activated RAW 264.7 cells, with IC50 values in the range of 0.32-7.8μM. In addition, all compounds were evaluated for potential to inhibit tumor necrosis factor-alpha (TNF-α)-activated nuclear factor-kappa B (NF-κB) activity with transfected human embryonic kidney cells 293. Compounds 4-7 inhibited TNF-α-induced NF-κB activity with IC50 values in the range of 0.04-5.6μM. Copyright © 2016 Elsevier Ltd. All rights reserved.

ReaxFF molecular dynamics simulation of intermolecular structure formation in acetic acid-water mixtures at elevated temperatures and pressures

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Sengul, Mert Y.; Randall, Clive A.; van Duin, Adri C. T.

2018-04-01

The intermolecular structure formation in liquid and supercritical acetic acid-water mixtures was investigated using ReaxFF-based molecular dynamics simulations. The microscopic structures of acetic acid-water mixtures with different acetic acid mole fractions (1.0 ≥ xHAc ≥ 0.2) at ambient and critical conditions were examined. The potential energy surface associated with the dissociation of acetic acid molecules was calculated using a metadynamics procedure to optimize the dissociation energy of ReaxFF potential. At ambient conditions, depending on the acetic acid concentration, either acetic acid clusters or water clusters are dominant in the liquid mixture. When acetic acid is dominant (0.4 ≤ xHAc), cyclic dimers and chain structures between acetic acid molecules are present in the mixture. Both structures disappear at increased water content of the mixture. It was found by simulations that the acetic acid molecules released from these dimer and chain structures tend to stay in a dipole-dipole interaction. These structural changes are in agreement with the experimental results. When switched to critical conditions, the long-range interactions (e.g., second or fourth neighbor) disappear and the water-water and acetic acid-acetic acid structural formations become disordered. The simulated radial distribution function for water-water interactions is in agreement with experimental and computational studies. The first neighbor interactions between acetic acid and water molecules are preserved at relatively lower temperatures of the critical region. As higher temperatures are reached in the critical region, these interactions were observed to weaken. These simulations indicate that ReaxFF molecular dynamics simulations are an appropriate tool for studying supercritical water/organic acid mixtures.

Tumor imaging and targeting potential of an Hsp70-derived 14-mer peptide.

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Mathias Gehrmann

Full Text Available We have previously used a unique mouse monoclonal antibody cmHsp70.1 to demonstrate the selective presence of a membrane-bound form of Hsp70 (memHsp70 on a variety of leukemia cells and on single cell suspensions derived from solid tumors of different entities, but not on non-transformed cells or cells from corresponding 'healthy' tissue. This antibody can be used to image tumors in vivo and target them for antibody-dependent cellular cytotoxicity. Tumor-specific expression of memHsp70 therefore has the potential to be exploited for theranostic purposes. Given the advantages of peptides as imaging and targeting agents, this study assessed whether a 14-mer tumor penetrating peptide (TPP; TKDNNLLGRFELSG, the sequence of which is derived from the oligomerization domain of Hsp70 which is expressed on the cell surface of tumor cells, can also be used for targeting membrane Hsp70 positive (memHsp70+ tumor cells, in vitro.The specificity of carboxy-fluorescein (CF- labeled TPP (TPP to Hsp70 was proven in an Hsp70 knockout mammary tumor cell system. TPP specifically binds to different memHsp70+ mouse and human tumor cell lines and is rapidly taken up via endosomes. Two to four-fold higher levels of CF-labeled TPP were detected in MCF7 (82% memHsp70+ and MDA-MB-231 (75% memHsp70+ cells compared to T47D cells (29% memHsp70+ that exhibit a lower Hsp70 membrane positivity. After 90 min incubation, TPP co-localized with mitochondrial membranes in memHsp70+ tumors. Although there was no evidence that any given vesicle population was specifically localized, fluorophore-labeled cmHsp70.1 antibody and TPP preferentially accumulated in the proximity of the adherent surface of cultured cells. These findings suggest a potential association between membrane Hsp70 expression and cytoskeletal elements that are involved in adherence, the establishment of intercellular synapses and/or membrane reorganization.This study demonstrates the specific binding and rapid

Potential radiosensitizing agents. 5. 2-Substituted benzimidazole derivatives

International Nuclear Information System (INIS)

Gupta, R.P.; Larroquette, C.A.; Agrawal, K.C.

1982-01-01

A series of 2-substituted benzimidazoles and their derivatives have been synthesized and tested for their ability to selectively sensitize hypoxic Chinese hamster cells (V-79) toward the lethal effect of ionizing radiation. These compounds were prepared by reacting the 2-substituted benzimidazoles with 1,2-epoxy-3-methoxypropane in the presence of potassium carbonate. Reaction of the 2-nitro and 2-methylfonyl analogue with the epoxide also yielded a cyclized material, which was confirmed to be a benzimidazo[2,1-b]oxazole. In an attempt to increase the electron affinity, 5- or 6-nitro-2-substituted-benzimidazoles were also synthesized and then reacted with the epoxide to yield the corresponding 1-substituted derivatives. The results of the biological tests for the radiosensitizing activity of these agents against Chinese hamster cells (V-79) in culture indicated that the 2-nitro-substituted analogues were the most effective sensitizers in this series

Human Amniotic Membrane-Derived Products in Sports Medicine: Basic Science, Early Results, and Potential Clinical Applications.

Science.gov (United States)

Riboh, Jonathan C; Saltzman, Bryan M; Yanke, Adam B; Cole, Brian J

2016-09-01

Amniotic membrane (AM)-derived products have been successfully used in ophthalmology, plastic surgery, and wound care, but little is known about their potential applications in orthopaedic sports medicine. To provide an updated review of the basic science and preclinical and clinical data supporting the use of AM-derived products and to review their current applications in sports medicine. Systematic review. A systematic search of the literature was conducted using the Medline, EMBASE, and Cochrane databases. The search term amniotic membrane was used alone and in conjunction with stem cell, orthopaedic, tissue engineering, scaffold, and sports medicine. The search identified 6870 articles, 80 of which, after screening of the titles and abstracts, were considered relevant to this study. Fifty-five articles described the anatomy, basic science, and nonorthopaedic applications of AM-derived products. Twenty-five articles described preclinical and clinical trials of AM-derived products for orthopaedic sports medicine. Because the level of evidence obtained from this search was not adequate for systematic review or meta-analysis, a current concepts review on the anatomy, physiology, and clinical uses of AM-derived products is presented. Amniotic membranes have many promising applications in sports medicine. They are a source of pluripotent cells, highly organized collagen, antifibrotic and anti-inflammatory cytokines, immunomodulators, and matrix proteins. These properties may make it beneficial when applied as tissue engineering scaffolds, improving tissue organization in healing, and treatment of the arthritic joint. The current body of evidence in sports medicine is heavily biased toward in vitro and animal studies, with little to no human clinical data. Nonetheless, 14 companies or distributors offer commercial AM products. The preparation and formulation of these products alter their biological and mechanical properties, and a thorough understanding of these

A zeta potential value determines the aggregate's size of penta-substituted [60]fullerene derivatives in aqueous suspension whereas positive charge is required for toxicity against bacterial cells.

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Deryabin, Dmitry G; Efremova, Ludmila V; Vasilchenko, Alexey S; Saidakova, Evgeniya V; Sizova, Elena A; Troshin, Pavel A; Zhilenkov, Alexander V; Khakina, Ekaterina A; Khakina, Ekaterina E

2015-08-08

The cause-effect relationships between physicochemical properties of amphiphilic [60]fullerene derivatives and their toxicity against bacterial cells have not yet been clarified. In this study, we report how the differences in the chemical structure of organic addends in 10 originally synthesized penta-substituted [60]fullerene derivatives modulate their zeta potential and aggregate's size in salt-free and salt-added aqueous suspensions as well as how these physicochemical characteristics affect the bioenergetics of freshwater Escherichia coli and marine Photobacterium phosphoreum bacteria. Dynamic light scattering, laser Doppler micro-electrophoresis, agarose gel electrophoresis, atomic force microscopy, and bioluminescence inhibition assay were used to characterize the fullerene aggregation behavior in aqueous solution and their interaction with the bacterial cell surface, following zeta potential changes and toxic effects. Dynamic light scattering results indicated the formation of self-assembled [60]fullerene aggregates in aqueous suspensions. The measurement of the zeta potential of the particles revealed that they have different surface charges. The relationship between these physicochemical characteristics was presented as an exponential regression that correctly described the dependence of the aggregate's size of penta-substituted [60]fullerene derivatives in salt-free aqueous suspension from zeta potential value. The prevalence of DLVO-related effects was shown in salt-added aqueous suspension that decreased zeta potential values and affected the aggregation of [60]fullerene derivatives expressed differently for individual compounds. A bioluminescence inhibition assay demonstrated that the toxic effect of [60]fullerene derivatives against E. coli cells was strictly determined by their positive zeta potential charge value being weakened against P. phosphoreum cells in an aquatic system of high salinity. Atomic force microscopy data suggested that the

Exploring the biocombinatorial potential of benzoxazoles: generation of novel caboxamycin derivatives.

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Losada, Armando A; Méndez, Carmen; Salas, José A; Olano, Carlos

2017-05-25

The biosynthesis pathway of benzoxazole compounds caboxamycin and nataxazole have been recently elucidated. Both compounds share one of their precursors, 3-hydroxyanthranilate (two units in the case of nataxazole). In addition, caboxamycin structure includes a salicylate moiety while 6-methylsalycilate is the third scaffold in nataxazole. Pathways cross-talk has been identified in caboxamycin producer Streptomyces sp. NTK937, between caboxamycin and enterobactin pathways, and nataxazole producer Streptomyces sp. Tü6176, between nataxazole and coelibactin pathways. These events represent a natural form of combinatorial biosynthesis. Eleven novel caboxamycin derivatives, and five putative novel derivatives, bearing distinct substitutions in the aryl ring have been generated. These compounds were produced by heterologous expression of several caboxamycin biosynthesis genes in Streptomyces albus J1074 (two compounds), by combinatorial biosynthesis in Streptomyces sp. NTK937 expressing nataxazole iterative polyketide synthase (two compounds) and by mutasynthesis using a nonproducing mutant of Streptomyces sp. NTK937 (12 compounds). Some of the compounds showed improved bioactive properties in comparison with caboxamycin. In addition to the benzoxazoles naturally biosynthesized by the caboxamycin and nataxazole producers, a greater structural diversity can be generated by mutasynthesis and heterologous expression of benzoxazole biosynthesis genes, not only in the respective producer strains but also in non-benzoxazole producers such as S. albus strains. These results show that the production of a wide variety of benzoxazoles could be potentially achieved by the sole expression of cbxBCDE genes (or orthologs thereof), supplying an external source of salicylate-like compounds, or with the concomitant expression of other genes capable of synthesizing salicylates, such as cbxA or natPK.

Trifluoromethyl Boron Dipyrromethene Derivatives as Potential Photosensitizers for Photodynamic Therapy

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Jian-Yong Liu

2018-02-01

Full Text Available In this study, two novel boron dipyrromethene-based photosensitizers (BDP3 and BDP6 substituted with three or six trifluoromethyl groups have been synthesized and characterized with various spectroscopic methods, and their photo-physical, photo-chemical, and photo-biological properties have also been explored. The two photosensitizers are highly soluble and remain nonaggregated in N,N-dimethylformamide as shown by the intense and sharp Q-band absorption. Under red light irradiation (λ = 660 nm, 1.5 J/cm2, both photosensitizers show high and comparable cytotoxicity towards HepG2 human hepatocarcinoma and HeLa human cervical carcinoma cells with IC50 values of 0.42–0.49 μM. The high photocytotoxicity of BDP3 and BDP6 can be due to their high cellular uptake and low aggregation tendency in biological media, which result in a high efficiency to generate reactive oxygen species inside the cells. Confocal laser fluorescence microscopic studies indicate that they have superior selective affinities to the mitochondria and lysosomes of HepG2 and HeLa cells. The results show that these two trifluoromethyl boron dipyrromethene derivatives are potential anticancer agents for photodynamic therapy.

Correlating electronic structure with corrosion inhibition potentiality of some bis-benzimidazole derivatives for mild steel in hydrochloric acid: Combined experimental and theoretical studies

International Nuclear Information System (INIS)

Dutta, Alokdut; Saha, Sourav Kr.; Banerjee, Priyabrata; Sukul, Dipankar

2015-01-01

Highlights: • Bis-benzimidazole derivatives as good corrosion inhibitors for mild steel in acid. • Simultaneous both way electron-transfer is expected to occur during adsorption. • Role of molecular conformation on inhibition efficiency is demonstrated. • Good correlation between inhibition efficiency and molecular parameters established. • MD simulation results support experimental observations. - Abstract: Four different bis-benzimidazole (BBI) derivatives, tested as potential corrosion inhibitors for mild steel in 1 M HCl, have revealed good inhibition efficiency for long period of exposure. Inhibitors impart high resistance towards charge transfer across metal–electrolyte interface and behave broadly as mixed type. DFT calculations are used to correlate inhibition potentiality with intrinsic molecular parameters. From the optimized geometry of BBI derivatives, electron distribution in HOMO and LUMO and Fukui indices of each atom, possible modes of interaction of BBI derivatives with mild steel surface have been predicted. Energy corresponding to inhibitor-metal surface interaction is evaluated following molecular dynamics simulation

Identification of novel 3,5-diarylpyrazoline derivatives containing salicylamide moiety as potential anti-melanoma agents.

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Li, Qing-Shan; Lv, Xian-Hai; Zhang, Yan-Bin; Dong, Jing-Jun; Zhou, Wen-Ping; Yang, Yang; Zhu, Hai-Liang

2012-11-01

There is an accumulating body of experimental evidences validating oncogenic BRAF(V600E) as a therapeutic target and offering opportunities for anti-melanoma drug development. Encouraged by the positive results of pyrazole derivatives as BRAF(V600E) inhibitors, we sought to design diverse novel potential BRAF(V600E) inhibitors as antitumor agents based on pyrazole skeleton. In silico and in vitro screening of our designed pyrazole derivatives has identified Hit 1 as BRAF(V600E) inhibitor. Based on its structure and through further structure modification, compound 25, which exhibited the most potent inhibitory activity with an IC(50) value of 0.16 μM for BRAF(V600E) and GI(50) value of 0.24 μM for mutant BRAF-dependent melanoma cells, was obtained. The 3D-QSAR models and the molecular docking simulation were introduced to analyze the structure-activity relationship. Copyright © 2012 Elsevier Ltd. All rights reserved.

The Potential of Chitosan and Its Derivatives in Prevention and Treatment of Age-Related Diseases

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Kerch, Garry

2015-01-01

Age-related, diet-related and protein conformational diseases, such as atherosclerosis, diabetes mellitus, cancer, hypercholesterolemia, cardiovascular and neurodegenerative diseases are common in the elderly population. The potential of chitosan, chitooligosaccharides and their derivatives in prevention and treatment of age-related dysfunctions is reviewed and discussed in this paper. The influence of oxidative stress, low density lipoprotein oxidation, increase of tissue stiffness, protein conformational changes, aging-associated chronic inflammation and their pathobiological significance have been considered. The chitosan-based functional food also has been reviewed. PMID:25871293

The mobility of Li+ and K+ ions in helium and argon at 294 and 80 K and derived interaction potentials

International Nuclear Information System (INIS)

Cassidy, R.A.; Elford, M.T.

1983-01-01

The analysis of mobility data is a valuable technique for deriving ion-atom interaction potentials or testing at initio potentials particularly at relatively large internuclear separations. In order to obtain the most complete information on the long range part of the potential it is necessary to have mobility data at sufficiently low gas temperatures and small values of E/N that the mobility is determined only by the dipole polarization force. Although this condition can be reasonably well met at room temperature for gases of high polarizability, this is not the case for ions in helium and in particular for the most well studied case, that of Li + in helium. The prime purpose of the present measurements was to obtain low temperature data for Li + in helium in order to determine more accurately the attractive long range tail of the potential. The measurements were also extended to argon to demonstrate the effect of the polarizability on the derivation of potentials. The mobility measurements were made using a drift tube-mass spectrometer system employing the Bradbury-Nielsen time of flight technique. Measurements were performed at 294 K and 80 K. The 'three temperature' theory of Lin, Viehland and Mason was used to fit interaction potentials to the present data. Detailed comparisons are made here only for the case of Li + ions in helium. The new data for 80 K provide additional information on the potential at internuclear separations which cover the range to 5 A. (Authors)

Synthesis and Pharmacological Evaluation of Novel Benzenesulfonamide Derivatives as Potential Anticonvulsant Agents

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Zhiming Wang

2015-09-01

Full Text Available A novel series of benzenesulfonamide derivatives containing 4-aminobenzenesul-fonamide and α-amides branched valproic acid or 2,2-dimethylcyclopropanecarboxylic acid moieties were synthesized and screened for their anticonvulsant activities in mice maximal electroshock seizure (MES and subcutaneous pentylenetetrazole (scPTZ test. The activity experimental study showed that 2,2-dipropyl-N1-(4-sulfamoylphenylmalonamide (18b had the lowest median effective dose (ED50 of 16.36 mg/kg in MES test, and 2,2-dimethyl-N-(4-sulfamoylphenylcyclopropane-1,1-dicarboxamide (12c had the lowest ED50 of 22.50 mg/kg in scPTZ test, which resulted in the protective indexe (PI of 24.8 and 20.4, respectively. These promising data suggest the new compounds have good potential as new class of anticonvulsant agents with high effectiveness and low toxicity for the treatment of epilepsy.

New bases for the evaluation of interaction energies: An ab initio study of the CO-Ne van der Waals complex intermolecular potential and ro-vibrational spectrum

International Nuclear Information System (INIS)

Bouzon Capelo, Silvia; Baranowska-Laczkowska, Angelika; Fernandez, Berta

2011-01-01

Graphical abstract: CO-Ne IPES. Highlights: → From the LPol, MLPol, and aug-pc-2 bases we obtained new bases for the evaluation of CO-Ne interaction energies. → We checked the bases on the evaluation of the rovibrational spectrum. → The results were satisfactory, being the new bases more efficient than those previously available. - Abstract: Recently we have derived new efficient basis sets for the evaluation of interaction energies in the X-Y (X, Y = He, Ne, Ar) van der Waals complexes. Here we extend the study to the CO-Ne complex. For this, we start with a systematic basis set study, where the LPol, MLPol and Jensen's aug-pc-2 basis sets are considered as starting point (for the Ne atom LPol bases are developed). As reference we take interaction energy results obtained with Dunning's augmented correlation consistent polarized valence basis sets. In all cases we test extensions with different sets of midbond functions. With the selected bases we evaluate CCSD(T) interaction potentials, and to check the potentials further, we obtain the ro-vibrational spectrum of the complex. The results are compared to the available experimental data.

Safe handling of potential peroxide forming compounds and their corresponding peroxide yielded derivatives.

Energy Technology Data Exchange (ETDEWEB)

Sears, Jeremiah Matthew; Boyle, Timothy J.; Dean, Christopher J.

2013-06-01

This report addresses recent developments concerning the identification and handling of potential peroxide forming (PPF) and peroxide yielded derivative (PYD) chemicals. PPF chemicals are described in terms of labeling, shelf lives, and safe handling requirements as required at SNL. The general peroxide chemistry concerning formation, prevention, and identification is cursorily presented to give some perspective to the generation of peroxides. The procedure for determining peroxide concentrations and the proper disposal methods established by the Hazardous Waste Handling Facility are also provided. Techniques such as neutralization and dilution are provided for the safe handling of any PYD chemicals to allow for safe handling. The appendices are a collection of all available SNL documentation pertaining to PPF/PYD chemicals to serve as a single reference.

Investigation on intermolecular interaction between berberine and β-cyclodextrin by 2D UV-Vis asynchronous spectra.

Science.gov (United States)

He, Anqi; Kang, Xiaoyan; Xu, Yizhuang; Noda, Isao; Ozaki, Yukihiro; Wu, Jinguang

2017-10-05

The interaction between berberine chloride and β-cyclodextrin (β-CyD) is investigated via 2D asynchronous UV-Vis spectrum. The occurrence of cross peaks around (420nm, 420nm) in 2D asynchronous spectrum reveals that specific intermolecular interaction indeed exists between berberine chloride and β-CyD. In spite of the difficulty caused by overlapping of cross peaks, we manage to confirm that the 420nm band of berberine undergoes a red-shift, and its bandwidth decreases under the interaction with β-CyD. The red-shift of the 420nm band that can be assigned to n-π* transition indicates the environment of berberine becomes more hydrophobic. The above spectral behavior is helpful in understanding why the solubility of berberine is enhanced by β-CyD. Copyright © 2017. Published by Elsevier B.V.

Articular cartilage-derived cells hold a strong osteogenic differentiation potential in comparison to mesenchymal stem cells in vitro

International Nuclear Information System (INIS)

Salamon, Achim; Jonitz-Heincke, Anika; Adam, Stefanie; Rychly, Joachim; Müller-Hilke, Brigitte; Bader, Rainer; Lochner, Katrin; Peters, Kirsten

2013-01-01

Cartilaginous matrix-degenerative diseases like osteoarthritis (OA) are characterized by gradual cartilage erosion, and also by increased presence of cells with mesenchymal stem cell (MSC) character within the affected tissues. Moreover, primary chondrocytes long since are known to de-differentiate in vitro and to be chondrogenically re-differentiable. Since both findings appear to conflict with each other, we quantitatively assessed the mesenchymal differentiation potential of OA patient cartilage-derived cells (CDC) towards the osteogenic and adipogenic lineage in vitro and compared it to that of MSC isolated from adipose tissue (adMSC) of healthy donors. We analyzed expression of MSC markers CD29, CD44, CD105, and CD166, and, following osteogenic and adipogenic induction in vitro, quantified their expression of osteogenic and adipogenic differentiation markers. Furthermore, CDC phenotype and proliferation were monitored. We found that CDC exhibit an MSC CD marker expression pattern similar to adMSC and a similar increase in proliferation rate during osteogenic differentiation. In contrast, the marked reduction of proliferation observed during adipogenic differentiation of adMSC was absent in CDC. Quantification of differentiation markers revealed a strong osteogenic differentiation potential for CDC, however almost no capacity for adipogenic differentiation. Since in the pathogenesis of OA, cartilage degeneration coincides with high bone turnover rates, the high osteogenic differentiation potential of OA patient-derived CDC may affect clinical therapeutic regimens aiming at autologous cartilage regeneration in these patients. - Highlights: • We analyze the mesenchymal differentiation capacity of cartilage-derived cells (CDC). • CDC express mesenchymal stem cell (MSC) markers CD29, CD44, CD105, and CD166. • CDC and MSC proliferation is reduced in adipogenesis and increased in osteogenesis. • Adipogenic differentiation is virtually absent in CDC, but

Articular cartilage-derived cells hold a strong osteogenic differentiation potential in comparison to mesenchymal stem cells in vitro

Energy Technology Data Exchange (ETDEWEB)

Salamon, Achim, E-mail: achim.salamon@med.uni-rostock.de [Department of Cell Biology, Rostock University Medical Center, Schillingallee 69, D-18057 Rostock (Germany); Jonitz-Heincke, Anika, E-mail: anika.jonitz@med.uni-rostock.de [Biomechanics and Implant Technology Research Laboratory, Department of Orthopedics, Rostock University Medical Center, Doberaner Straße 142, D-18057 Rostock (Germany); Adam, Stefanie, E-mail: stefanie.adam@med.uni-rostock.de [Department of Cell Biology, Rostock University Medical Center, Schillingallee 69, D-18057 Rostock (Germany); Rychly, Joachim, E-mail: joachim.rychly@med.uni-rostock.de [Department of Cell Biology, Rostock University Medical Center, Schillingallee 69, D-18057 Rostock (Germany); Müller-Hilke, Brigitte, E-mail: brigitte.mueller-hilke@med.uni-rostock.de [Institute of Immunology, Rostock University Medical Center, Schillingallee 68, D-18057 Rostock (Germany); Bader, Rainer, E-mail: rainer.bader@med.uni-rostock.de [Biomechanics and Implant Technology Research Laboratory, Department of Orthopedics, Rostock University Medical Center, Doberaner Straße 142, D-18057 Rostock (Germany); Lochner, Katrin, E-mail: katrin.lochner@med.uni-rostock.de [Biomechanics and Implant Technology Research Laboratory, Department of Orthopedics, Rostock University Medical Center, Doberaner Straße 142, D-18057 Rostock (Germany); Peters, Kirsten, E-mail: kirsten.peters@med.uni-rostock.de [Department of Cell Biology, Rostock University Medical Center, Schillingallee 69, D-18057 Rostock (Germany)

2013-11-01

Cartilaginous matrix-degenerative diseases like osteoarthritis (OA) are characterized by gradual cartilage erosion, and also by increased presence of cells with mesenchymal stem cell (MSC) character within the affected tissues. Moreover, primary chondrocytes long since are known to de-differentiate in vitro and to be chondrogenically re-differentiable. Since both findings appear to conflict with each other, we quantitatively assessed the mesenchymal differentiation potential of OA patient cartilage-derived cells (CDC) towards the osteogenic and adipogenic lineage in vitro and compared it to that of MSC isolated from adipose tissue (adMSC) of healthy donors. We analyzed expression of MSC markers CD29, CD44, CD105, and CD166, and, following osteogenic and adipogenic induction in vitro, quantified their expression of osteogenic and adipogenic differentiation markers. Furthermore, CDC phenotype and proliferation were monitored. We found that CDC exhibit an MSC CD marker expression pattern similar to adMSC and a similar increase in proliferation rate during osteogenic differentiation. In contrast, the marked reduction of proliferation observed during adipogenic differentiation of adMSC was absent in CDC. Quantification of differentiation markers revealed a strong osteogenic differentiation potential for CDC, however almost no capacity for adipogenic differentiation. Since in the pathogenesis of OA, cartilage degeneration coincides with high bone turnover rates, the high osteogenic differentiation potential of OA patient-derived CDC may affect clinical therapeutic regimens aiming at autologous cartilage regeneration in these patients. - Highlights: • We analyze the mesenchymal differentiation capacity of cartilage-derived cells (CDC). • CDC express mesenchymal stem cell (MSC) markers CD29, CD44, CD105, and CD166. • CDC and MSC proliferation is reduced in adipogenesis and increased in osteogenesis. • Adipogenic differentiation is virtually absent in CDC, but

Effects of intermolecular interactions on the stability of carbon nanotube–gold nanoparticle conjugates in solution

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Konczak L

2016-11-01

Full Text Available Lukasz Konczak,1 Jolanta Narkiewicz-Michalek,2 Giorgia Pastorin,3 Tomasz Panczyk1 1Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Cracow, 2Department of Chemistry, Maria Curie-Sklodowska University, Lublin, Poland; 3Department of Pharmacy, National University of Singapore, Singapore Abstract: This work deals with the role of intermolecular interactions in the stability of a carbon nanotube (CNT capped by functionalized gold nanoparticles (AuNPs. The importance of such a system is due to its potential application as a pH-controlled drug carrier. Our preliminary experimental studies showed that fabrication of such a nanobottle/nanocontainer is feasible and it is possible to encapsulate the anticancer drug cisplatin inside the inner space of a CNT and seal its ends by functionalized AuNPs. The expected behavior, that is, detachment of AuNPs at acidic pH and the release of cisplatin, was, however, not observed. On the other hand, our theoretical studies of chemically identical system led to the conclusion that the release of cisplatin at acidic pH should be observed. Therefore, in this work, a deeper theoretical analysis of various factors that could be responsible for the disagreement between experimental and theoretical results were performed. The study found that the major factor is a large dispersion interaction component acting between CNT and AuNP in solution in the case of the experimental system. This factor can be controlled to some extent by tuning the system size or the ratio between AuNP diameter and CNT diameter. Thus, such kind of a pH-sensitive drug carrier is still of great interest, but its structural parameters need to be properly adjusted. Keywords: hydrazone bond, drug delivery, dispersion interactions, cisplatin, acidic pH

Intermolecular interactions of trifluorohalomethanes with Lewis bases in the gas phase: an ab initio study.

Science.gov (United States)

Wang, Yi-Siang; Yin, Chih-Chien; Chao, Sheng D

2014-10-07

We perform an ab initio computational study of molecular complexes with the general formula CF3X-B that involve one trifluorohalomethane CF3X (X = Cl or Br) and one of a series of Lewis bases B in the gas phase. The Lewis bases are so chosen that they provide a range of electron-donating abilities for comparison. Based on the characteristics of their electron pairs, we consider the Lewis bases with a single n-pair (NH3 and PH3), two n-pairs (H2O and H2S), two n-pairs with an unsaturated bond (H2CO and H2CS), and a single π-pair (C2H4) and two π-pairs (C2H2). The aim is to systematically investigate the influence of the electron pair characteristics and the central atom substitution effects on the geometries and energetics of the formed complexes. The counterpoise-corrected supermolecule MP2 and coupled-cluster single double with perturbative triple [CCSD(T)] levels of theory have been employed, together with a series of basis sets up to aug-cc-pVTZ. The angular and radial configurations, the binding energies, and the electrostatic potentials of the stable complexes have been compared and discussed as the Lewis base varies. For those complexes where halogen bonding plays a significant role, the calculated geometries and energetics are consistent with the σ-hole model. Upon formation of stable complexes, the C-X bond lengths shorten, while the C-X vibrational frequencies increase, thus rendering blueshifting halogen bonds. The central atom substitution usually enlarges the intermolecular bond distances while it reduces the net charge transfers, thus weakening the bond strengths. The analysis based on the σ-hole model is grossly reliable but requires suitable modifications incorporating the central atom substitution effects, in particular, when interaction components other than electrostatic contributions are involved.

Embryonic stem cells derived from in vivo or in vitro-generated murine blastocysts display similar transcriptome and differentiation potential.

Directory of Open Access Journals (Sweden)

Rhodel K Simbulan

Full Text Available The use of assisted reproductive technologies (ART such as in vitro fertilization (IVF has resulted in the birth of more than 5 million children. While children conceived by these technologies are generally healthy, there is conflicting evidence suggesting an increase in adult-onset complications like glucose intolerance and high blood pressure in IVF children. Animal models indicate similar potential risks. It remains unclear what molecular mechanisms may be operating during in vitro culture to predispose the embryo to these diseases. One of the limitations faced by investigators is the paucity of the material in the preimplantation embryo to test for molecular analysis. To address this problem, we generated mouse embryonic stem cells (mESC from blastocysts conceived after natural mating (mESCFB or after IVF, using optimal (KSOM + 5% O2; mESCKAA and suboptimal (Whitten's Medium, + 20% O2, mESCWM conditions. All three groups of embryos showed similar behavior during both derivation and differentiation into their respective mESC lines. Unsupervised hierarchical clustering of microarray data showed that blastocyst culture does not affect the transcriptome of derived mESCs. Transcriptomic changes previously observed in the inner cell mass (ICM of embryos derived in the same conditions were not present in mESCs, regardless of method of conception or culture medium, suggesting that mESC do not fully maintain a memory of the events occurring prior to their derivation. We conclude that the fertilization method or culture media used to generate blastocysts does not affect differentiation potential, morphology and transcriptome of mESCs.

Potential of a polygonal prism and lamina; Takakuchu men no potential

Energy Technology Data Exchange (ETDEWEB)

Koyama, S

1996-05-01

With the use of rectangular coordinates O-XYZ, the potential of a calculation point P is expressed in the form of a triple repeated integral of a density {sigma} at point Q in the mass. The potential at the density {sigma} assumed to be 1 is named the potential of a polygonal prism. Further, a double repeated integral with an integral concerning Z removed from the triple integral is named the potential of polygonal lamina. This potential can be expressed in a quadratic form (linear form) with 2nd order partial derivative (1st order partial derivative) as a coefficient. On the contrary, in order to extract the 1st/2nd order partial derivatives from this potential by partial differential, it requires partial differentiation with these partial derivatives considered to be a constant. The reason that they can be realized is attributable to the zero result of the linear form which has as the coefficient a 3rd order partial derivative concerning the variable of integration in a primitive function. If this relation is used, the integral calculation and description may be simplified. An explanation was given with examples enumerated so that these conditions might be understood.

Influence of obstetric factors on osteogenic potential of umbilical cord-derived mesenchymal stem cells

Directory of Open Access Journals (Sweden)

Canella Alessandro

2009-10-01

Full Text Available Abstract Wharton's jelly from the umbilical cord is a noncontroversial source of mesenchymal stem cells (WJMSCs with high plasticity, proliferation rate and ability to differentiate towards multiple lineages. WJMSCs from different donors have been characterized for their osteogenic potential. Although there is large evidence of WJMSCs plasticity, recently scientific debate has focused on MSCs selection, establishing predictable elements to discriminate the cells with most promising osteoprogenitor cell potential. In the present study a comparative study between the presence of osteoblastic markers and different parameters that pertain to both the newborn and the mother was performed. Umbilical cords were collected after all patients signed the informed consent and local ethical commettee approved the study. Obstetric parameters, including baby's gender and birth weight, mother's age at delivery, gestational stage at parturition and mode of delivery were examined. After characterization and expansion, WJMSCs were analyzed for two osteoblastic markers, alkaline phosphatase (ALP activity, and the expression level of RUNX-2 transcription factor, and for their ability to deposit mineralized matrix after osteogenic induction. We found that osteoblastic potential was not influenced by baby's gender and mode of delivery. On the contrary, the highest degree of osteoblastic potential has been shown by WJMSCs with RUNX-2 high basal levels, selected from umbilical cords of the heaviest term babies. Even if further evaluation is required, our hypothesis is that our findings may help in selecting the optimal umbilical cord donors and in collecting high potential Wharton's jelly-derived osteoprogenitors efficiently.

Quantum mechanical force field for water with explicit electronic polarization.

Science.gov (United States)

Han, Jaebeom; Mazack, Michael J M; Zhang, Peng; Truhlar, Donald G; Gao, Jiali

2013-08-07

A quantum mechanical force field (QMFF) for water is described. Unlike traditional approaches that use quantum mechanical results and experimental data to parameterize empirical potential energy functions, the present QMFF uses a quantum mechanical framework to represent intramolecular and intermolecular interactions in an entire condensed-phase system. In particular, the internal energy terms used in molecular mechanics are replaced by a quantum mechanical formalism that naturally includes electronic polarization due to intermolecular interactions and its effects on the force constants of the intramolecular force field. As a quantum mechanical force field, both intermolecular interactions and the Hamiltonian describing the individual molecular fragments can be parameterized to strive for accuracy and computational efficiency. In this work, we introduce a polarizable molecular orbital model Hamiltonian for water and for oxygen- and hydrogen-containing compounds, whereas the electrostatic potential responsible for intermolecular interactions in the liquid and in solution is modeled by a three-point charge representation that realistically reproduces the total molecular dipole moment and the local hybridization contributions. The present QMFF for water, which is called the XP3P (explicit polarization with three-point-charge potential) model, is suitable for modeling both gas-phase clusters and liquid water. The paper demonstrates the performance of the XP3P model for water and proton clusters and the properties of the pure liquid from about 900 × 10(6) self-consistent-field calculations on a periodic system consisting of 267 water molecules. The unusual dipole derivative behavior of water, which is incorrectly modeled in molecular mechanics, is naturally reproduced as a result of an electronic structural treatment of chemical bonding by XP3P. We anticipate that the XP3P model will be useful for studying proton transport in solution and solid phases as well as across

From potential to reality. Yeasts derived from ethanol production for animal nutrition

International Nuclear Information System (INIS)

Fernandes, E.A.N.; Trevizam, A.B.; Nepomuceno, N.; Amorim, H.V.

1998-01-01

The high costs of cereals and vegetable protein supplements used for animal nutrition have directed much attention toward non-conventional alternative protein sources. Brazil has a significant potential to provide such material, since it is the world's largest producer of ethanol (13 billion liters per year) derived from fermentation by yeasts (sugar cane being the basic raw material). Distilleries are recovering surplus yeast to produce dry yeast for use in animal food formulations. With regard to the yeast biomass elemental composition, INAA analyses performed on a pool of samples from various different fermentations have shown the presence of various trace elements, e.g. As, Br, Ca, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Na, Rb, Sc, Sm, Th, and Zn. This reinforces the need for additional studies concerning the suitability of yeast in terms of maximum tolerable levels of these elements in formulations for domestic animals. (author)

"Precipitation on Nanoparticles": Attractive Intermolecular Interactions Stabilize Specific Ligand Ratios on the Surfaces of Nanoparticles.

Science.gov (United States)

Chu, Zonglin; Han, Yanxiao; Kral, Petr; Klajn, Rafal

2018-04-19

Confining organic molecules to the surfaces of inorganic nanoparticles can induce intermolecular interactions between them, which can affect the composition of the mixed self-assembled monolayers obtained by co-adsorption from solution of two different molecules. Here, we study co-adsorption of two thiolated ligands-a dialkylviologen and a zwitterionic sulfobetaine-that can interact with each other electrostatically, onto gold nanoparticles. Consequently, the nanoparticles favor a narrow range of ratios of these two molecules that is largely independent of the molar ratio in solution. We show that changing the solution molar ratio of two ligands by a factor of ~5,000 affects the on-nanoparticle ratio of these ligands by only 3 times. This behavior is reminiscent of the formation of insoluble inorganic salts (e.g., AgCl), which similarly compensate positive and negative charges upon crystallizing. Our results pave the way towards developing well-defined hybrid organic-inorganic nanostructures. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Intermolecular and very strong intramolecular C-SeO/N chalcogen bonds in nitrophenyl selenocyanate crystals.

Science.gov (United States)

Wang, Hui; Liu, Ju; Wang, Weizhou

2018-02-14

Single-crystal X-ray diffraction reveals that polymorphic ortho-nitrophenyl selenocyanate (o-NSC, crystals 1a and 1b) and monomorphic para-nitrophenyl selenocyanate (p-NSC, crystal 2) crystals are all stabilized mainly by intermolecular and very strong intramolecular C-SeO/N chalcogen bonds, as well as by other different interactions. Thermogravimetric (TG) and differential scanning calorimetry thermogram (DSC) analyses show that the starting decomposition temperatures and melting points of the three crystals are different, following the order 1b > 1a > 2, which is consistent with the structural characteristics of the crystals. In addition, atoms in molecules (AIM) and natural bond orbital (NBO) analyses indicate that the total strengths of the C-SeO and C-SeN chalcogen bonds decrease in the order 1b > 1a > 2. This study could be significant for engineering functional crystals based on robust C-SeO and C-SeN chalcogen bonds, and for designing drugs containing selenium as well as understanding their interaction in biosystems.

5-Bromo-2-aryl benzimidazole derivatives as non-cytotoxic potential dual inhibitors of α-glucosidase and urease enzymes.

Science.gov (United States)

Arshad, Tanzila; Khan, Khalid Mohammed; Rasool, Najma; Salar, Uzma; Hussain, Shafqat; Asghar, Humna; Ashraf, Mohammed; Wadood, Abdul; Riaz, Muhammad; Perveen, Shahnaz; Taha, Muhammad; Ismail, Nor Hadiani

2017-06-01

On the basis of previous report on promising α-glucosidase inhibitory activity of 5-bromo-2-aryl benzimidazole derivatives, these derivatives were further screened for urease inhibitory and cytotoxicity activity in order to get more potent and non-cytotoxic potential dual inhibitor for the patients suffering from diabetes as well as peptic ulcer. In this study, all compounds showed varying degree of potency in the range of (IC 50 =8.15±0.03-354.67±0.19μM) as compared to standard thiourea (IC 50 =21.25±0.15μM). It is worth mentioning that derivatives 7 (IC 50 =12.07±0.05μM), 8 (IC 50 =10.57±0.12μM), 11 (IC 50 =13.76±0.02μM), 14 (IC 50 =15.70±0.12μM) and 22 (IC 50 =8.15±0.03μM) were found to be more potent inhibitors than standard. All compounds were also evaluated for cytotoxicity towards 3T3 mouse fibroblast cell line and found to be completely non-toxic. Previously benzimidazole 1-25 were also showed α-glucosidase inhibitory potential. In silico studies were performed on the lead molecules i.e.2, 7, 8, 11, 14, and 22, in order to rationalize the binding interaction of compounds with the active site of urease enzyme. Copyright © 2017 Elsevier Inc. All rights reserved.

Anti-addiction Drug Ibogaine Prolongs the Action Potential in Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes.

Science.gov (United States)

Rubi, Lena; Eckert, Daniel; Boehm, Stefan; Hilber, Karlheinz; Koenig, Xaver

2017-04-01

Ibogaine is a plant alkaloid used as anti-addiction drug in dozens of alternative medicine clinics worldwide. Recently, alarming reports of life-threatening cardiac arrhythmias and cases of sudden death associated with the ingestion of ibogaine have accumulated. Using whole-cell patch clamp recordings, we assessed the effects of ibogaine and its main metabolite noribogaine on action potentials in human ventricular-like cardiomyocytes derived from induced pluripotent stem cells. Therapeutic concentrations of ibogaine and its long-lived active metabolite noribogaine significantly retarded action potential repolarization in human cardiomyocytes. These findings represent the first experimental proof that ibogaine application entails a cardiac arrhythmia risk for humans. In addition, they explain the clinically observed delayed incidence of cardiac adverse events several days after ibogaine intake. We conclude that therapeutic concentrations of ibogaine retard action potential repolarization in the human heart. This may give rise to a prolongation of the QT interval in the electrocardiogram and cardiac arrhythmias.

Arginine-phosphate salt bridges between histones and DNA: Intermolecular actuators that control nucleosome architecture

Science.gov (United States)

Yusufaly, Tahir I.; Li, Yun; Singh, Gautam; Olson, Wilma K.

2014-10-01

Structural bioinformatics and van der Waals density functional theory are combined to investigate the mechanochemical impact of a major class of histone-DNA interactions, namely, the formation of salt bridges between arginine residues in histones and phosphate groups on the DNA backbone. Principal component analysis reveals that the configurational fluctuations of the sugar-phosphate backbone display sequence-specific directionality and variability, and clustering of nucleosome crystal structures identifies two major salt-bridge configurations: a monodentate form in which the arginine end-group guanidinium only forms one hydrogen bond with the phosphate, and a bidentate form in which it forms two. Density functional theory calculations highlight that the combination of sequence, denticity, and salt-bridge positioning enables the histones to apply a tunable mechanochemical stress to the DNA via precise and specific activation of backbone deformations. The results suggest that selection for specific placements of van der Waals contacts, with high-precision control of the spatial distribution of intermolecular forces, may serve as an underlying evolutionary design principle for the structure and function of nucleosomes, a conjecture that is corroborated by previous experimental studies.

Conformer-Specific IR Spectroscopy of Laser-Desorbed Sulfonamide Drugs: Tautomeric and Conformational Preferences of Sulfanilamide and its Derivatives

Science.gov (United States)

Uhlemann, Thomas; Seidel, Sebastian; Müller, Christian W.

2017-06-01

Molecules containing the sulfonamide group R^{1}-SO_2-NHR^{2} have a longstanding history as antimicrobial agents. Even though nowadays they are not commonly used in treating humans anymore, they continue to be studied as effective inhibitors of metalloenzyme carbonic anhydrases. These enzymes are important targets for a variety of diseases, such as, for instance, breast cancer, glaucoma, and obesity. Here we present the results of our laser desorption single-conformation UV and IR study of sulfanilamide (NH_2Ph-SO_2-NHR, R=H), a variety of singly substituted derivatives, and their monohydrated complexes. Depending on the substituent, the sulfonamide group can either adopt an amino or an imino tautomeric form. The form prevalent in the crystal is not necessarily also the tautomeric form we identified in the molecular beam after laser desorbing the sample. Furthermore, we explored the effect of complexation with a single water molecule on the tautomeric and conformational preferences of the sulfonamides. Our conformer-specific IR spectra in the NH and OH stretch region (3200-3750 \\wn) suggest that the intra- and intermolecular interactions governing the structures of the monomers and water complexes are surprisingly diverse. We have undertaken both Quantum Theory of Atoms in Molecules (QTAIM) and Interacting Quantum Atoms (IQA) analyses of calculated electron densities to quantitatively characterize the nature and strengths of the intra- and intermolecular interactions prevalent in the monomer and water complex structures.

Prolonged hypoxic culture and trypsinization increase the pro-angiogenic potential of human adipose tissue-derived stem cells

DEFF Research Database (Denmark)

Rasmussen, Jeppe Grøndahl; Frøbert, Ole; Pilgaard, Linda

2011-01-01

Transplantation of mesenchymal stromal cells (MSC), including adipose tissue-derived stem cells (ASC), is a promising option in the treatment of vascular disease. Short-term hypoxic culture of MSC augments secretion of anti-apoptotic and angiogenic cytokines. We hypothesized that prolonged hypoxic...... (1% and 5% oxygen) culture and trypsinization would augment ASC expression of anti-apoptotic and angiogenic cytokines and increase the angiogenic potential of ASC-conditioned media....

The Role and Potential Therapeutic Application of Myeloid-Derived Suppressor Cells in Allo- and Autoimmunity

Directory of Open Access Journals (Sweden)

Qi Zhang

2015-01-01

Full Text Available Myeloid-derived suppressor cells (MDSCs are a heterogeneous population of cells that consists of myeloid progenitor cells and immature myeloid cells. They have been identified as a cell population that may affect the activation of CD4+ and CD8+ T-cells to regulate the immune response negatively, which makes them attractive targets for the treatment of transplantation and autoimmune diseases. Several studies have suggested the potential suppressive effect of MDSCs on allo- and autoimmune responses. Conversely, MDSCs have also been found at various stages of differentiation, accumulating during pathological situations, not only during tumor development but also in a variety of inflammatory immune responses, bone marrow transplantation, and some autoimmune diseases. These findings appear to be contradictory. In this review, we summarize the roles of MDSCs in different transplantation and autoimmune diseases models as well as the potential to target these cells for therapeutic benefit.

Theoretical investigation of potential energy surface and bound states for the van der Waals complex Ar–BrCl dimer

Energy Technology Data Exchange (ETDEWEB)

Zheng, Rui [School of Mathematics and Information Science, North China University of Water Resources and Electric Power, Zhengzhou (China); Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Centre for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan (China); Li, Song, E-mail: lsong@yangtzeu.edu.cn [School of Physics and Optoelectronic Engineering, Yangtze University, Jingzhou (China); Chen, Shan-Jun; Chen, Yan [School of Physics and Optoelectronic Engineering, Yangtze University, Jingzhou (China); Zheng, Li-Min [Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Centre for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan (China)

2015-09-08

Highlights: • A two-dimensional potential for Ar–BrCl is constructed at the CCSD(T) level. • The PES is characterized by three minima and two saddle points between them. • Bound state calculations were carried out for the complex. - Abstract: The intermolecular potential energy surface (PES) of the ground electronic state for the Ar–BrCl dimer is constructed at the CCSD(T) level with the aug-cc-pVQZ basis set and mid-bond functions. The PES is characterized by three minima and two saddle points. The global minimum corresponding to a collinear Ar–BrCl configuration, which has been observed experimentally, is located at R = 4.10 Å and θ = 2.5° with a well depth of −285.207 cm{sup −1}. A nearly T-shaped structure and an anti-linear Ar–ClBr geometry is also predicted. The bound state calculations are preformed to study intermolecular vibrational modes, rotational levels and average structures for the complex. Our transition frequencies, spectroscopic constants and average structures for all isotopomers of the collinear isomer agree well with experimental data. We have also provided pure rotational transitional frequencies for both nearly T-shaped and anti-linear isomers. These results are significant for further experimental investigations of the Ar–BrCl dimer.

Study of quartz-glass using Roentgen- and neutron-diffraction

International Nuclear Information System (INIS)

Sikkenk, P.J.

1988-08-01

An X-ray diffraction measurement, with wavelength 0.0711 nm, is made of a vitreous silica to kappa of 200nm -1 . (faculty of materials science) A second X-ray diffraction measurement has been executed (National Laboratory Oak Ridge). For this research we also used neutron diffraction measurement (IRI), with wavelength 0.085 nm of a vitreous silica to kappa of 132 nm -1 . The intermolecular scattering functions derived from the X-ray measurements and neutron measurements by omitting the intramolecular scattering contribution. A theoretical model for the structure of vitreous silica is used, derived from a mixture of Si en SiO-4 units. The partial scattering functions i-S-i---S-i is determined with help of the model and the intermolecular X-ray scattering functions and intermolecular neutron scattering functions and intermolecular neutron scatteirng functions. The fouriertransform of the partial scattering function i-S-i---S-i leads to the partial radial correlation function. When this partial radial correlation function is compared to a correlation function directly obtained by the intermolecular scattering function, a considerable increase of the resolution is observed in the partial correlation function if r > 0.29 nm and r < 0.45 nm. (author). 16 refs.; 30 figs.; 9 tabs

CP/MAS 13C NMR characterization of the isomeric states and intermolecular packing in tris(8-hydroxyquinoline) aluminum(III) (Alq3).

Science.gov (United States)

Kaji, Hironori; Kusaka, Yasunari; Onoyama, Goro; Horii, Fumitaka

2006-04-05

The isomeric states and intermolecular packing of tris(8-hydroxyquinoline) aluminum(III) (Alq(3)) in the alpha-, gamma-, and delta-crystalline forms and in the amorphous state, which are important for understanding the light-emitting and electron-transport properties, have been analyzed by CP/MAS (13)C NMR. This simple NMR experiment shows that the isomeric state of alpha- and amorphous Alq(3) is meridional, whereas that of gamma- and delta-Alq(3) is facial. In the amorphous Alq(3), the inclusion of facial isomers has been under debate. Our experiments show that meridional isomers are dominant in the amorphous Alq(3), although the existence of facial isomers cannot be completely denied. The local structure of amorphous Alq(3) is similar to that of alpha-Alq(3) and is significantly different from those of gamma- and delta-Alq(3). Among these Alq(3) samples, the effect of intermolecular interaction is not found only for gamma-Alq(3). This finding can explain the good solvent solubility of gamma-Alq(3), compared with the other crystalline forms. It is also shown that the structures are locally disordered not only for amorphous Alq(3) but also for alpha-Alq(3), although clear X-ray diffraction peaks are observed for alpha-Alq(3). In contrast, the local structures of gamma- and delta-Alq(3) are well defined. A clear relation is found between the spectral patterns of CP/MAS (13)C NMR and the fluorescence wavelengths; the samples, which consist of facial isomers, show blue-shifted fluorescence compared with those of meridionals.

Ligand field and intermolecular interactions tuning the magnetic properties of spin-crossover Fe(II) polymer with 4,4′-bipyridine

Energy Technology Data Exchange (ETDEWEB)

Luo, Yang-Hui; Liu, Qing-Ling; Yang, Li-Jing; Ling, Yang; Wang, Wei; Sun, Bai-Wang, E-mail: chmsunbw@seu.edu.cn

2015-02-15

A new spin crossover coordination polymer (SCO-CPs) of Fe(II)-4,4′-bipyridine (4,4′-bipy) family: (Fe(4,4′-bipy){sub 2}(H{sub 2}O){sub 2})·(4,4′-bipy)· 8(H{sub 2}O)·2(ClO{sub 4}) (3), which displays half spin transitions between 100 and 300 K, has been synthesized and structurally characterized. Compound 3 featured with two-dimensional (2-D) grids connected by hydrogen bonds and π…π packing between one-dimensional (1-D) chains, the 2-D grids expand to three-dimensional (3-D) architecture supported by a “S-shaped holder” involving lattice 4-4′-bipy, water molecules and perchlorate anion. We compared 3 with the other two analogous complexes: ((Fe(4,4′-bipy) (H{sub 2}O){sub 2} (NCS){sub 2})·4,4′-bipy, 1 and (Fe(4,4′-bipy){sub 2}(NCS){sub 2})·mSolv, 2) through Hirshfeld surfaces analysis, which revealed that the low ligand field strength (NCS{sup −}) and lone-pair…H contacts contribute to the stabilization of HS (high-spin) state of the Fe(II) ion, while the high ligand field strength (4,4′-bipy) and strong intermolecular contacts (hydrogen bonds and π…π packing interactions) make for the LS (low-spin) state. - Highlights: ●A new member of Fe(||)-4,4′-bipy family has been prepared. ●It displays half spin transitions tuned by ligand field and intermolecular interactions. ●We have made a detailed comparison of this new member with two other analogous complexes.

Temperature-dependent interaction potential between NF3 molecules and thermophysical properties of gaseous NF3

International Nuclear Information System (INIS)

Damyanova, M; Balabanova, E; Hohm, U

2014-01-01

A temperature-dependent effective intermolecular interaction potential is applied to describe the interaction between two nitrogen fluoride (NF 3 ) molecules in gas phase. To this end, a spherically-symmetric (n-6) Lennard-Jones temperature-dependent potential (LJTDP) is used. The (n-6) LJTDP takes into account the influence of vibrational excitation of the molecules on the potential parameters, namely, the equilibrium distance r m and the potential well depth ε. The potential parameters at T = 0 K were obtained from the very small amount of existing thermophysical equilibrium and transport properties of low-density NF 3 gas. Fitting formulae are tabulated for a fast and reliable prediction of the thermophysical properties and potential parameters in the temperature range between 200 K and 1200 K. A comparison is also presented between our estimates for some thermophysical properties of the NF 3 gas with the available experimental and calculated data.

Drosophila melanogaster "a potential model organism" for identification of pharmacological properties of plants/plant-derived components.

Science.gov (United States)

Panchal, Komal; Tiwari, Anand K

2017-05-01

Plants/plant-derived components have been used from ancient times to treat/cure several human diseases. Plants and their parts possess several chemical components that play the vital role in the improvement of human health and their life expectancy. Allopathic medicines have been playing a key role in the treatment of several diseases. Though allopathic medicines provide fast relief, long time consumption cause serious health concerns such as hyperallergic reactions, liver damage, etc. So, the study of medicinal plants which rarely cause any side effect is very important to mankind. Plants contain many health benefit properties like antioxidant, anti-aging, neuroprotective, anti-genotoxic, anti-mutagenic and bioinsecticidal activity. Thus, identification of pharmacological properties of plants/plant-derived components are of utmost importance to be explored. Several model organisms have been used to identify the pharmacological properties of the different plants or active components therein and Drosophila is one of them. Drosophila melanogaster "fruit fly" is a well understood, high-throughput model organism being used more than 110 years to study the different biological aspects related to the development and diseases. Most of the developmental and cell signaling pathways and ∼75% human disease-related genes are conserved between human and Drosophila. Using Drosophila, one can easily analyze the pharmacological properties of plants/plant-derived components by performing several assays available with flies such as survivorship, locomotor, antioxidant, cell death, etc. The current review focuses on the potential of Drosophila melanogaster for the identification of medicinal/pharmacological properties associated with plants/plant-derived components. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Relativistic effects in the intermolecular interaction-induced nuclear magnetic resonance parameters of xenon dimer.

Science.gov (United States)

Hanni, Matti; Lantto, Perttu; Ilias, Miroslav; Jensen, Hans Jorgen Aagaard; Vaara, Juha

2007-10-28

Relativistic effects on the (129)Xe nuclear magnetic resonance shielding and (131)Xe nuclear quadrupole coupling (NQC) tensors are examined in the weakly bound Xe(2) system at different levels of theory including the relativistic four-component Dirac-Hartree-Fock (DHF) method. The intermolecular interaction-induced binary chemical shift delta, the anisotropy of the shielding tensor Deltasigma, and the NQC constant along the internuclear axis chi( parallel) are calculated as a function of the internuclear distance. DHF shielding calculations are carried out using gauge-including atomic orbitals. For comparison, the full leading-order one-electron Breit-Pauli perturbation theory (BPPT) is applied using a common gauge origin. Electron correlation effects are studied at the nonrelativistic (NR) coupled-cluster singles and doubles with perturbational triples [CCSD(T)] level of theory. The fully relativistic second-order Moller-Plesset many-body perturbation (DMP2) theory is used to examine the cross coupling between correlation and relativity on NQC. The same is investigated for delta and Deltasigma by BPPT with a density functional theory model. A semiquantitative agreement between the BPPT and DHF binary property curves is obtained for delta and Deltasigma in Xe(2). For these properties, the currently most complete theoretical description is obtained by a piecewise approximation where the uncorrelated relativistic DHF results obtained close to the basis-set limit are corrected, on the one hand, for NR correlation effects and, on the other hand, for the BPPT-based cross coupling of relativity and correlation. For chi( parallel), the fully relativistic DMP2 results obtain a correction for NR correlation effects beyond MP2. The computed temperature dependence of the second virial coefficient of the (129)Xe nuclear shielding is compared to experiment in Xe gas. Our best results, obtained with the piecewise approximation for the binary chemical shift combined with the

Machine Learning Intermolecular Potentials for 1,3,5-Triamino-2,4,6-trinitrobenzene (TATB) Using Symmetry-Adapted Perturbation Theory

Science.gov (United States)

2018-04-25

Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that...speech recognition,3 fraud prevention,4 spam email filtering,5 unmanned vehicle operation ,6 finance,7 and even drunk driver detection,8 ML has now...Ridge Regression KRR can be derived from Eq. 2 by ignoring the bias term b, setting ε = 0, and squaring the “ slack variables” ξ. This yields the

Solvable potentials derived from supersymmetric quantum mechanics

International Nuclear Information System (INIS)

Levai, G.

1994-01-01

The introduction of supersymmetric quantum mechanics has generated renewed interest in solvable problems of non-relativistic quantum mechanics. This approach offers an elegant way to describe different, but isospectral potentials by interpreting the degeneracy of their energy levels in terms of supersymmetry. The original ideas of supersymmetric quantum mechanics have been developed further in many respects in the past ten years, and have been applied to a large variety of physical problems. The purpose of this contribution is to give a survey of supersymmetric quantum mechanics and its applications to solvable quantum mechanical potentials. Its relation to other models describing isospectral potentials is also discussed here briefly, as well as some of its practical applications in various branches of physics. (orig.)

Nitroxide stable radicals interacting as Lewis bases in hydrogen bonds: A search in the Cambridge structural data base for intermolecular contacts

Science.gov (United States)

Alkorta, Ibon; Elguero, José; Elguero, Eric

2017-11-01

1125 X-ray structures of nitroxide free radicals presenting intermolecular hydrogen bonds have been reported in the Cambridge Structural Database. We will report in this paper a qualitative and quantitative analysis of these bonds. The observation in some plots of an excluded region was statistically analyzed using convex hull and kernel smooting methodologies. A theoretical study at the MP2 level with different basis has been carried out indicating that the nitronyl nitroxide radicals (five electrons) lie just in between nitroso compounds (four electrons) and amine N-oxides (six electrons) as far as hydrogen-bond basicity is concerned.

THERMODYNAMIC DEPRESSION OF IONIZATION POTENTIALS IN NONIDEAL PLASMAS: GENERALIZED SELF-CONSISTENCY CRITERION AND A BACKWARD SCHEME FOR DERIVING THE EXCESS FREE ENERGY

International Nuclear Information System (INIS)

Zaghloul, Mofreh R.

2009-01-01

Accurate and consistent prediction of thermodynamic properties is of great importance in high-energy density physics and in modeling stellar atmospheres and interiors as well. Modern descriptions of thermodynamic properties of such nonideal plasma systems are sophisticated and/or full of pitfalls that make it difficult, if not impossible, to reproduce. The use of the Saha equation modified at high densities by incorporating simple expressions for depression of ionization potentials is very convenient in that context. However, as it is commonly known, the incorporation of ad hoc or empirical expressions for the depression of ionization potentials in the Saha equation leads to thermodynamic inconsistencies. The problem of thermodynamic consistency of ionization potentials depression in nonideal plasmas is investigated and a criterion is derived, which shows immediately, whether a particular model for the ionization potential depression is self-consistent, that is, whether it can be directly related to a modification of the free-energy function, or not. A backward scheme is introduced which can be utilized to derive nonideality corrections to the free-energy function from formulas of ionization potentials depression derived from plasma microfields or in ad hoc or empirical fashion provided that the aforementioned self-consistency criterion is satisfied. The value and usefulness of such a backward method are pointed out and discussed. The above-mentioned criterion is applied to investigate the thermodynamic consistency of some historic models in the literature and an optional routine is introduced to recover their thermodynamic consistencies while maintaining the same functional dependence on the species densities as in the original models. Sample computational problems showing the effect of the proposed modifications on the computed plasma composition are worked out and presented.

Effects on the structure of monolayer and submonolayer fluid nitrogen films by the corrugation in the holding potential of nitrogen molecules

DEFF Research Database (Denmark)

Hansen, Flemming Yssing

2001-01-01

of interactions were indicated by the comparison of the calculated and measured isosteric heats of adsorption in fluid films of nitrogen molecules on graphite. The melting temperatures were lowered by 7K and a region of liquid-gas coexistence was observed for films on the smooth graphite surface indicating......The effects of corrugation in the holding potential of nitrogen molecules on the structure of fluid monolayer and submonolayer films of the molecules on a solid substrate was studied using molecular dynamics simulation. Including McLachlan mediation of the intermolecular potential in a model...

Therapeutic potential of helminths in autoimmune diseases: helminth-derived immune-regulators and immune balance.

Science.gov (United States)

Wang, Meng; Wu, Linxiang; Weng, Rennan; Zheng, Weihong; Wu, Zhongdao; Lv, Zhiyue

2017-08-01

Helminths have accompanied human throughout history by releasing immune-evasion molecules that could counteract an aberrant immune response within the host. In the past decades, helminth infections are becoming less prevalent possibly due to the developed sanitation. Meanwhile, the incidence of autoimmune diseases is increasing, which cannot be exclusively explained by the changes of susceptibility genes. While the hygiene hypothesis casts light on the problem. The infections of helminths are believed to interact with and regulate human immunity with the byproduct of suppressing the autoimmune diseases. Thus, helminths are potential to treat or cure the autoimmune diseases. The therapeutic progresses and possible immune suppression mechanisms are illustrated in the review. The helminths that are studied most intensively include Heligmosomoides polygyrus, Hymenolepis diminuta, Schistosoma mansoni, Trichinella spiralis, and Trichuris suis. Special attentions are paid on the booming animal models and clinical trials that are to detect the efficiency of immune-modulating helminth-derived molecules on autoimmune diseases. These trials provide us with a prosperous clinical perspective, but the precise mechanism of the down-regulatory immune response remains to be clarified. More efforts are needed to be dedicated until these parasite-derived immune modulators could be used in clinic to treat or cure the autoimmune diseases under a standard management.

Skin appendage-derived stem cells: cell biology and potential for wound repair

OpenAIRE

Xie, Jiangfan; Yao, Bin; Han, Yutong; Huang, Sha; Fu, Xiaobing

2016-01-01

Stem cells residing in the epidermis and skin appendages are imperative for skin homeostasis and regeneration. These stem cells also participate in the repair of the epidermis after injuries, inducing restoration of tissue integrity and function of damaged tissue. Unlike epidermis-derived stem cells, comprehensive knowledge about skin appendage-derived stem cells remains limited. In this review, we summarize the current knowledge of skin appendage-derived stem cells, including their fundament...

Potential of iPSC-Derived Mesenchymal Stromal Cells for Treating Periodontal Disease

Directory of Open Access Journals (Sweden)

K. Hynes

2018-01-01

Full Text Available Mesenchymal stromal cell-like populations have been derived from mouse-induced pluripotent stem cells (miPSC-MSC with the capability for tissue regeneration. In this study, murine iPSC underwent differentiation towards an MSC-like immunophenotype. Stable miPSC-MSC cultures expressed the MSC-associated markers, CD73, CD105, and Sca-1, but lacked expression of the pluripotency marker, SSEA1, and hematopoietic markers, CD34 and CD45. Functionally, miPSC-MSC exhibited the potential for trilineage differentiation into osteoblasts, adipocytes, and chondrocytes and the capacity to suppress the proliferation of mitogen-activated splenocytes. The efficacy of miPSC-MSC was assessed in an acute inflammation model following systemic or local delivery into mice with subcutaneous implants containing heat-inactivated P. gingivalis. Histological analysis revealed less inflammatory cellular infiltrate within the sponges in mice treated with miPSC-MSC cells delivered locally rather than systemically. Assessment of proinflammatory cytokines in mouse spleens found that CXCL1 transcripts and protein were reduced in mice treated with miPSC-MSC. In a periodontitis model, mice subjected to oral inoculation with P. gingivalis revealed less bone tissue destruction and inflammation within the jaws when treated with miPSC-MSC compared to PBS alone. Our results demonstrated that miPSC-MSC derived from iPSC have the capacity to control acute and chronic inflammatory responses associated with the destruction of periodontal tissue. Therefore, miPSC-MSC present a promising novel source of stromal cells which could be used in the treatment of periodontal disease and other inflammatory systemic diseases such as rheumatoid arthritis.

The interaction of MnH(X 7Sigma+) with He: ab initio potential energy surface and bound states.

Science.gov (United States)

Turpin, Florence; Halvick, Philippe; Stoecklin, Thierry

2010-06-07

The potential energy surface of the ground state of the He-MnH(X (7)Sigma(+)) van der Waals complex is presented. Within the supermolecular approach of intermolecular energy calculations, a grid of ab initio points was computed at the multireference configuration interaction level using the aug-cc-pVQZ basis set for helium and hydrogen and the relativistic aug-cc-pVQZ-DK basis set for manganese. The potential energy surface was then fitted to a global analytical form which main features are discussed. As a first application of this potential energy surface, we present accurate calculations of bound energy levels of the (3)He-MnH and (4)He-MnH complexes.

The interaction of MnH(X 7Σ+) with He: Ab initio potential energy surface and bound states

Science.gov (United States)

Turpin, Florence; Halvick, Philippe; Stoecklin, Thierry

2010-06-01

The potential energy surface of the ground state of the He-MnH(X Σ7+) van der Waals complex is presented. Within the supermolecular approach of intermolecular energy calculations, a grid of ab initio points was computed at the multireference configuration interaction level using the aug-cc-pVQZ basis set for helium and hydrogen and the relativistic aug-cc-pVQZ-DK basis set for manganese. The potential energy surface was then fitted to a global analytical form which main features are discussed. As a first application of this potential energy surface, we present accurate calculations of bound energy levels of the H3e-MnH and H4e-MnH complexes.

Effects of Intermolecular Coupling on Excimer Formation and Singlet Fission

Science.gov (United States)

Mauck, Catherine McKay

compelling strategy for improving organic photovoltaic device efficiencies. The formation of triplet states through singlet fission can be characterized using femtosecond visible transient absorption spectroscopy (fsTA). However, in PDI, the triplet-triplet absorption spectrum is strongly overlapped with the ground state bleach absorption. Here, a dyad molecule where PDI is covalently attached to an apocarotene triplet acceptor is synthesized, and studied in solution aggregates and thin films with fsTA, to demonstrate that apocarotene can be used as a sensitive spectral tag for triplet formation in PDI due to triplet-triplet energy transfer from PDI to the carotenoid. The efficiency of singlet fission in DPP can be tuned by modulating the crystal packing in the solid state. By synthesizing 3,6-bis(thiophene) derivatives of DPP with a series of different sidechains, thin film DPP singlet fission is related to the crystal structure intermolecular geometries, to more precisely determine the relationship between interchromophore coupling and singlet fission rate, which will inform the design of more robust chromophores for singlet fission. Finally, the role of the dielectric environment and stabilization of charge transfer configurations and charge transfer states is explored in DPP singlet fission, through aqueous nanoparticles of 3,6-bis(phenylthiophene) with different surface area-to-volume ratios, and a covalently linked dimer of DPP in solvents of varying polarity which can undergo symmetry-breaking charge separation.

Stereoselective synthesis of diazaspiro[5.5]undecane derivatives via base promoted [5+1] double Michael addition of N,N-dimethylbarbituric acid to diaryliedene acetones

Directory of Open Access Journals (Sweden)

Mohammad Shahidul Islam

2017-01-01

Full Text Available The nitrogen containing spiro-heterocycle is one of the privileged synthetic motif that constitutes various naturally occurring molecules and displays a broad range of pharmaceutical and biological activities. A new methodology was developed for the synthesis of 2,4-diazaspiro[5.5]undecane-1,3,5,9-tetraones spiro-heterocyclic derivatives via cascade cyclization of [5+1] double Michael addition reaction of N,N-dimethylbarbituric acid with the derivatives of diaryldivinylketones in the presence of diethylamine at ambient temperature. The developed protocol is highly capable of furnishing diazaspiro[5.5]undecane derivatives 3a–m in excellent yields (up to 98%, from easily accessible symmetric and non-symmetric divinylketones 2a–m, containing aryl and heteroaryl substituents. The diazaspiro-heterocyclic structure was mainly elucidated by NMR and X-ray crystallographic techniques. The single-crystal X-ray studies revealed that, the cyclohexanone unit of spirocycles often prefers a chair conformation rather than twisted conformation. The intermolecular hydrogen bonding and CArH⋯π, π–π stacking interactions driving forces are mainly responsible for the crystal packing.

Spectroscopy and reaction dynamics of collision complexes containing hydroxyl radicals

Energy Technology Data Exchange (ETDEWEB)

Lester, M.I. [Univ. of Pennsylvania, Philadelphia (United States)

1993-12-01

The DOE supported work in this laboratory has focused on the spectroscopic characterization of the interaction potential between an argon atom and a hydroxyl radical in the ground X{sup 2}II and excited A {sup 2}{summation}{sup +} electronic states. The OH-Ar system has proven to be a test case for examining the interaction potential in an open-shell system since it is amenable to experimental investigation and theoretically tractable from first principles. Experimental identification of the bound states supported by the Ar + OH (X {sup 2}II) and Ar + OH(A {sup 2}{summation}{sup +}) potentials makes it feasible to derive realistic potential energy surfaces for these systems. The experimentally derived intermolecular potentials provide a rigorous test of ab initio theory and a basis for understanding the dramatically different collision dynamics taking place on the ground and excited electronic state surfaces.

6-Nitrobenzimidazole derivatives: potential phosphodiesterase inhibitors: synthesis and structure-activity relationship.

Science.gov (United States)

Khan, K M; Shah, Zarbad; Ahmad, V U; Ambreen, N; Khan, M; Taha, M; Rahim, F; Noreen, S; Perveen, S; Choudhary, M I; Voelter, W

2012-02-15

6-Nitrobenzimidazole derivatives (1-30) synthesized and their phosphodiesterase inhibitory activities determined. Out of thirty tested compounds, ten showed a varying degrees of phosphodiesterase inhibition with IC(50) values between 1.5±0.043 and 294.0±16.7 μM. Compounds 30 (IC(50)=1.5±0.043 μM), 1 (IC(50)=2.4±0.049 μM), 11 (IC(50)=5.7±0.113 μM), 13 (IC(50)=6.4±0.148 μM), 14 (IC(50)=10.5±0.51 μM), 9 (IC(50)=11.49±0.08 μM), 3 (IC(50)=63.1±1.48 μM), 10 (IC(50)=120.0±4.47 μM), and 6 (IC(50)=153.2±5.6 μM) showed excellent phosphodiesterase inhibitory activity, much superior to the standard EDTA (IC(50)=274±0.007 μM), and thus are potential molecules for the development of a new class of phosphodiesterase inhibitors. A structure-activity relationship is evaluated. All compounds are characterized by spectroscopic parameters. Copyright © 2011 Elsevier Ltd. All rights reserved.

SERCA plays a crucial role in the toxicity of a betulinic acid derivative with potential antimalarial activity.

Science.gov (United States)

Diedrich, Denise; Wildner, Andreia C; Silveira, Thayse F; Silva, Gloria N S; Santos, Francine Dos; da Silva, Elenilson F; do Canto, Vanessa P; Visioli, Fernanda; Gosmann, Grace; Bergold, Ana M; Zimmer, Aline R; Netz, Paulo A; Gnoatto, Simone C B

2018-05-01

Malaria is one of the most significant infectious diseases that affect poor populations in tropical areas throughout the world. Plants have been shown to be a good source for the development of new antimalarial chemotherapeutic agents, as shown for the discovery of quinine and artemisinin derivatives. Our research group has been working with semisynthetic triterpene derivatives that show potential antimalarial activity toward different strains of Plasmodium falciparum by specifically modulating calcium pathways in the parasite. Promising results were obtained for nanomolar concentrations of the semisynthetic betulinic acid derivative LAFIS13 against the P. falciparum 3D7 strain in vitro, with a selectivity index of 18 compared to a mammalian cell line. Continuing these studies, we present here in vitro and in vivo toxicological evaluations of this compound, followed by docking studies with PfATP6, a sarco/endoplasmic reticulum Ca +2 -ATPase (SERCA) protein. LAFIS13 showed an LD 50 between 300 and 50 mg/kg, and the acute administration of 50 mg/kg (i.p.) had no negative effects on hematological, biochemical and histopathological parameters. Based on the results of the in vitro assays, LAFIS13 not exerted significant effects on coagulation parameters of human peripheral blood, but a hemolytic activity was verified at higher concentrations. According to the molecular docking study, the PfATP6 protein may be a target for LAFIS13, which corroborates its previously reported modulatory effects on calcium homeostasis in the parasite. Notably, LAFIS13 showed a higher selectivity for the mammalian SERCA protein than for PfATP6, thus impairing the selectivity between parasite and host. In summary, the direct interaction with calcium pumps and the hemolytic potential of the compound proved to be plausible mechanism of LAFIS13 toxicity. Copyright © 2018 Elsevier B.V. All rights reserved.

Release of bisphenol A and its derivatives from orthodontic adhesive systems available on the European market as a potential health risk factor

Directory of Open Access Journals (Sweden)

Konrad Małkiewicz

2015-02-01

1 In conditions of the current experiment it was demonstrated that most of the assessed orthodontic adhesive resins available on the European market and released into the outside environment – biologically harmful bisphenol A or its derivatives, posing a potential threat to the patients’ health. 2 Release of BPA and its derivatives into aqueous solutions is the highest in the early stages of sample incubation.

Genetic plasticity of the Shigella virulence plasmid is mediated by intra- and inter-molecular events between insertion sequences.

Science.gov (United States)

Pilla, Giulia; McVicker, Gareth; Tang, Christoph M

2017-09-01

Acquisition of a single copy, large virulence plasmid, pINV, led to the emergence of Shigella spp. from Escherichia coli. The plasmid encodes a Type III secretion system (T3SS) on a 30 kb pathogenicity island (PAI), and is maintained in a bacterial population through a series of toxin:antitoxin (TA) systems which mediate post-segregational killing (PSK). The T3SS imposes a significant cost on the bacterium, and strains which have lost the plasmid and/or genes encoding the T3SS grow faster than wild-type strains in the laboratory, and fail to bind the indicator dye Congo Red (CR). Our aim was to define the molecular events in Shigella flexneri that cause loss of Type III secretion (T3S), and to examine whether TA systems exert positional effects on pINV. During growth at 37°C, we found that deletions of regions of the plasmid including the PAI lead to the emergence of CR-negative colonies; deletions occur through intra-molecular recombination events between insertion sequences (ISs) flanking the PAI. Furthermore, by repositioning MvpAT (which belongs to the VapBC family of TA systems) near the PAI, we demonstrate that the location of this TA system alters the rearrangements that lead to loss of T3S, indicating that MvpAT acts both globally (by reducing loss of pINV through PSK) as well as locally (by preventing loss of adjacent sequences). During growth at environmental temperatures, we show for the first time that pINV spontaneously integrates into different sites in the chromosome, and this is mediated by inter-molecular events involving IS1294. Integration leads to reduced PAI gene expression and impaired secretion through the T3SS, while excision of pINV from the chromosome restores T3SS function. Therefore, pINV integration provides a reversible mechanism for Shigella to circumvent the metabolic burden imposed by pINV. Intra- and inter-molecular events between ISs, which are abundant in Shigella spp., mediate plasticity of S. flexneri pINV.

Biological Activity Predictions and Hydrogen Bonding Analysis in Quinolines

Science.gov (United States)

Gupta, Palvi; Kamni

The paper has been designed to make a comprehensive review of a particular series of organic molecular assembly in the form of compendium. An overview of general description of fifteen quinoline derivatives has been given. The biological activity spectra of quinoline derivatives have been correlated on structure activity relationships base which provides the different Pa (possibility of activity) and Pi (possibility of inactivity) values. Expositions of the role of intermolecular interactions in the identified derivatives have been discussed with the standard distance and angle cut-off criteria criteria as proposed by Desiraju and Steiner (1999) in an International monogram on crystallography. Distance-angle scatter plots for intermolecular interactions are presented for a better understanding of the packing interactions which exist in quinoline derivatives.

Mexico; Financial Sector Assessment Program Update: Technical Note: Derivatives Market: Overview and Potential Vulnerabilities

OpenAIRE

International Monetary Fund

2007-01-01

This technical note provides an overview of Mexico’s derivatives markets, and describes concisely the derivatives regulatory framework and risk management practices in financial institutions active in these markets. The most important derivatives market in Mexico is the over-the-counter (OTC) derivatives market, which is fully integrated with the global derivatives market. The origin of the OTC derivatives market can be traced back to the 1994 Mexican crisis that forced Mexico to abandon its ...

Long-stem shaped multifunctional molecular beacon for highly sensitive nucleic acids determination via intramolecular and intermolecular interactions based strand displacement amplification.

Science.gov (United States)

Xu, Jianguo; Zheng, Tingting; Le, Jingqing; Jia, Lee

2017-11-20

Occurrence and application of oligonucleotide probes have promoted great progress in the biochemical analysis field due to their unique biological and chemical properties. In this work, a long-stem shaped multifunctional molecular beacon (LS-MMB) that is responsive to a cancer-related gene, p53, is well-prepared. By designing the probe with long-paired bases at its two ends and short-paired bases between the middle region and the 3' end, the LS-MMB is intelligently endowed with the ability to recognize the target analyte, serve as the polymerization primer/template, and signal the hybridization event synchronously, which is distinctly advantageous over the traditional molecular beacons (MBs). Moreover, it is excitingly found that the LS-MMB can be employed to exert intramolecular and intermolecular interactions for strand displacement amplification (SDA) without the involvement of any assistant probes; this therapy results in a really easy and rapid sensing system that provides an extremely low background noise and high target output signal. In this case, an excellent sensitivity and specificity to detect target gene down to picomolar level and resolution to even one nucleotide variation are achieved, respectively. In addition, the application potential for real genomic DNA analysis is realized. We envision that the probe of LS-MMB can act as a universal platform for biosensing and biomedical research.

New insights into the dual fluorescence of methyl salicylate: effects of intermolecular hydrogen bonding and solvation.

Science.gov (United States)

Zhou, Panwang; Hoffmann, Mark R; Han, Keli; He, Guozhong

2015-02-12

In this paper, we propose a new and complete mechanism for dual fluorescence of methyl salicylate (MS) under different conditions using a combined experimental (i.e., steady-state absorption and emission spectra and time-resolved fluorescence spectra) and theoretical (i.e., time-dependent density function theory) study. First, our theoretical study indicates that the barrier height for excited state intramolecular proton transfer (ESIPT) reaction of ketoB depends on the solvent polarity. In nonpolar solvents, the ESIPT reaction of ketoB is barrierless; the barrier height will increase with increasing solvent polarity. Second, we found that, in alcoholic solvents, intermolecular hydrogen bonding plays a more important role. The ketoB form of MS can form two hydrogen bonds with alcoholic solvents; one will facilitate ESIPT and produce the emission band in the blue region; the other one precludes ESIPT and produces the emission band in the near-UV region. Our proposed new mechanism can well explain previous results as well as our new experimental results.

A new terthiophene derivative as a fluorescent sensor for protein detection

International Nuclear Information System (INIS)

Hu, Jingqiu; Xia, Bing; Elioff, Michael S.

2016-01-01

A terthiophene carboxylic derivative, 3,3″-dihexyl-2,2′:5′,2″-terthiophene-5-carboxylic acid (3TC6A), was synthesized and its application as fluorescent biosensor was investigated using Bovine Serum Albumin (BSA) and Lectin from Triticum as the target proteins. The photophysical properties of terthiophene carboxylic acid depend on the solvent polarity and the pH of the solution. At low concentrations, the dye exhibits monomer emission in organic solvents. In acidic and neutral aqueous solutions, it displays dimer emission (490–500 nm). The emission can be completely quenched by heptyl viologen in aqueous solutions due to intermolecular electron transfer. While no emission enhancement was observed in the presence of cytochrome C, hemoglobin, or lysozyme, upon binding to trace amounts of BSA, the dye displayed strongly enhanced monomer emission at 450 nm. Upon binding to Lectin from Triticum vulgaris, the dye displayed enhanced dimer emission at 490 nm. In both cases, the fluorescence intensity is proportional to the concentration of proteins, making this organic dye a promising reagent for protein analysis.

A new terthiophene derivative as a fluorescent sensor for protein detection

Energy Technology Data Exchange (ETDEWEB)

Hu, Jingqiu [Department of Chemistry, West Chester University of Pennsylvania, West Chester, PA 19383 (United States); Xia, Bing [RD Platform Technology & Science, GlaxoSmithKline, Waltham, MA 02451 (United States); Elioff, Michael S., E-mail: melioff@millersville.edu [Department of Chemistry, Millersville University of Pennsylvania, Millersville, PA 17551 (United States)

2016-05-15

A terthiophene carboxylic derivative, 3,3″-dihexyl-2,2′:5′,2″-terthiophene-5-carboxylic acid (3TC6A), was synthesized and its application as fluorescent biosensor was investigated using Bovine Serum Albumin (BSA) and Lectin from Triticum as the target proteins. The photophysical properties of terthiophene carboxylic acid depend on the solvent polarity and the pH of the solution. At low concentrations, the dye exhibits monomer emission in organic solvents. In acidic and neutral aqueous solutions, it displays dimer emission (490–500 nm). The emission can be completely quenched by heptyl viologen in aqueous solutions due to intermolecular electron transfer. While no emission enhancement was observed in the presence of cytochrome C, hemoglobin, or lysozyme, upon binding to trace amounts of BSA, the dye displayed strongly enhanced monomer emission at 450 nm. Upon binding to Lectin from Triticum vulgaris, the dye displayed enhanced dimer emission at 490 nm. In both cases, the fluorescence intensity is proportional to the concentration of proteins, making this organic dye a promising reagent for protein analysis.

Proper construction of ab initio global potential surfaces with accurate long-range interactions

International Nuclear Information System (INIS)

Ho, Tak-San; Rabitz, Herschel

2000-01-01

An efficient procedure based on the reproducing kernel Hilbert space interpolation method is presented for constructing intermolecular potential energy surfaces (PES) using not only calculated ab initio data but also a priori information on long-range interactions. Explicitly, use of the reciprocal power reproducing kernel on the semiinfinite interval [0,∞) yields a set of exact linear relations between dispersion (multipolar) coefficients and PES data points at finite internuclear separations. Consequently, given a combined set of ab initio data and the values of dispersion (multipolar) coefficients, the potential interpolation problem subject to long-range interaction constraints can be solved to render globally smooth, asymptotically accurate ab initio potential energy surfaces. Very good results have been obtained for the one-dimensional He-He potential curve and the two-dimensional Ne-CO PES. The construction of the Ne-CO PES was facilitated by invoking a new reproducing kernel for the angular coordinate based on the optimally stable and shape-preserving Bernstein basis functions. (c) 2000 American Institute of Physics

Synthesis and Structural Characterization of 1- and 2-Substituted Indazoles: Ester and Carboxylic Acid Derivatives

Directory of Open Access Journals (Sweden)

Isabel Bento

2006-11-01

Full Text Available A series of indazoles substituted at the N-1 and N-2 positions with ester-containing side chains -(CH2nCO2R of different lengths (n = 0-6, 9, 10 are described.Nucleophilic substitution reactions on halo esters (X(CH2nCO2R by 1H-indazole inalkaline solution lead to mixtures of N-1 and N-2 isomers, in which the N-1 isomerpredominates. Basic hydrolysis of the ester derivatives allowed the synthesis of thecorresponding indazole carboxylic acids. All compounds were fully characterised bymultinuclear NMR and IR spectroscopies, MS spectrometry and elemental analysis; theNMR spectroscopic data were used for structural assignment of the N-1 and N-2 isomers.The molecular structure of indazol-2-yl-acetic acid (5b was determined by X-raydiffraction, which shows a supramolecular architecture involving O2-H...N1intermolecular hydrogen bonds.

Probing the global potential energy minimum of (CH2O)2: THz absorption spectrum of (CH2O)2 in solid neon and para-hydrogen

DEFF Research Database (Denmark)

Andersen, Jonas; Voute, A.; Mihrin, Dmytro

2017-01-01

)2 embedded in cryogenic neon and enriched para-hydrogen matrices. A (semi)-empirical value for the change of vibrational zero-point energy of 5.5 ± 0.3 kJ mol−1 is proposed for the dimerization process. These THz spectroscopic observations are complemented by CCSD(T)-F12/aug-cc-pV5Z (electronic......The true global potential energy minimum configuration of the formaldehyde dimer (CH2O)2, including the presence of a single or a double weak intermolecular CH⋯O hydrogen bond motif, has been a long-standing subject among both experimentalists and theoreticians as two different energy minima...... conformations of Cs and C2h symmetry have almost identical energies. The present work demonstrates how the class of large-amplitude hydrogen bond vibrational motion probed in the THz region provides excellent direct spectroscopic observables for these weak intermolecular CH⋯O hydrogen bond motifs...

Adipose-derived stem cells retain their regenerative potential after methotrexate treatment

International Nuclear Information System (INIS)

Beane, Olivia S.; Fonseca, Vera C.; Darling, Eric M.

2014-01-01

In musculoskeletal tissues like bone, chemotherapy can impair progenitor cell differentiation and proliferation, resulting in decreased bone growth and mineralization throughout a patient's lifetime. In the current study, we investigated the effects of chemotherapeutics on adipose-derived stem cell (ASC) function to determine whether this cell source could be a candidate for repairing, or even preventing, chemotherapy-induced tissue damage. Dose-dependent proliferation rates of ASCs and normal human fibroblasts (NHFs) were quantified after treatment with cytarabine (CY), etoposide (ETO), methotrexate (MTX), and vincristine (VIN) using a fluorescence-based assay. The influence of MTX on the multipotency of ASCs and freshly isolated stromal vascular fraction (SVF) cells was also evaluated using lineage-specific stains and spectrophotometry. ASC and NHF proliferation were equally inhibited by exposure to CY and ETO; however, when treated with MTX and VIN, ASCs exhibited greater resistance. This was especially apparent for MTX-treated samples, with ASC proliferation showing no inhibition for clinically relevant MTX doses ranging from 0.1 to 50 μM. Additional experiments revealed that the differentiation potential of ASCs was not affected by MTX treatment and that upregulation of dihydrofolate reductase possibly contributed to this response. Moreover, SVF cells, which include ASCs, exhibited similar resistance to MTX impairment, with respect to cellular proliferation, clonogenicity, and differentiation capability. Therefore, we have shown that the regenerative properties of ASCs resist the cytotoxicity of MTX, identifying these cells as a potential key for repairing musculoskeletal damage in patients undergoing chemotherapy. - Highlights: • Long-term effects of chemotherapeutics can include musculoskeletal dysfunction. • A screen of common drugs showed disparate effects on ASCs and fibroblasts. • One drug, methotrexate, did not impair ASC growth

Adipose-derived stem cells retain their regenerative potential after methotrexate treatment

Energy Technology Data Exchange (ETDEWEB)

Beane, Olivia S. [Center for Biomedical Engineering, Brown University, Providence, RI (United States); Fonseca, Vera C. [Department of Molecular Pharmacology, Physiology, and Biotechnology, Brown University, Providence, RI (United States); Darling, Eric M., E-mail: Eric_Darling@brown.edu [Center for Biomedical Engineering, Brown University, Providence, RI (United States); Department of Molecular Pharmacology, Physiology, and Biotechnology, Brown University, Providence, RI (United States); Department of Orthopaedics, Brown University, Providence, RI (United States); School of Engineering, Brown University, Providence, RI (United States)

2014-10-01

In musculoskeletal tissues like bone, chemotherapy can impair progenitor cell differentiation and proliferation, resulting in decreased bone growth and mineralization throughout a patient's lifetime. In the current study, we investigated the effects of chemotherapeutics on adipose-derived stem cell (ASC) function to determine whether this cell source could be a candidate for repairing, or even preventing, chemotherapy-induced tissue damage. Dose-dependent proliferation rates of ASCs and normal human fibroblasts (NHFs) were quantified after treatment with cytarabine (CY), etoposide (ETO), methotrexate (MTX), and vincristine (VIN) using a fluorescence-based assay. The influence of MTX on the multipotency of ASCs and freshly isolated stromal vascular fraction (SVF) cells was also evaluated using lineage-specific stains and spectrophotometry. ASC and NHF proliferation were equally inhibited by exposure to CY and ETO; however, when treated with MTX and VIN, ASCs exhibited greater resistance. This was especially apparent for MTX-treated samples, with ASC proliferation showing no inhibition for clinically relevant MTX doses ranging from 0.1 to 50 μM. Additional experiments revealed that the differentiation potential of ASCs was not affected by MTX treatment and that upregulation of dihydrofolate reductase possibly contributed to this response. Moreover, SVF cells, which include ASCs, exhibited similar resistance to MTX impairment, with respect to cellular proliferation, clonogenicity, and differentiation capability. Therefore, we have shown that the regenerative properties of ASCs resist the cytotoxicity of MTX, identifying these cells as a potential key for repairing musculoskeletal damage in patients undergoing chemotherapy. - Highlights: • Long-term effects of chemotherapeutics can include musculoskeletal dysfunction. • A screen of common drugs showed disparate effects on ASCs and fibroblasts. • One drug, methotrexate, did not impair ASC growth

Data in support of intermolecular interactions at early stage of protein/detergent particle association induced by salt/polyethylene glycol mixtures

Directory of Open Access Journals (Sweden)

Takayuki Odahara

2016-06-01

Full Text Available The data provide information in support of the research article, “Intermolecular interactions at early stage of protein/detergent particle association induced by salt/polyethylene glycol mixtures” [1]. The data regarding variation of absorption spectra is used as an indicator of the duration of Rp. viridis PRU and RC, Rb. sphaeroides RC and LH2, and Rb. capsulatus LH2 in the native state in the presence of NaCl/polyethylene glycol (PEG mixture. The data about minimum concentrations of salt and PEG whose aqueous phases are mutually separated presents information on additional influence of Tris buffer and N-octyl-β-d-glucoside on the salt–PEG phase separation.

Ultrafast responses of dipolar and V-shaped dipicolinate derivatives with potential applications in the labeling of biomolecules

Science.gov (United States)

Wang, Yaochuan; Liu, Siyuan; Liu, Dajun; Wang, Guiqiu; Xiao, Haibo

2016-02-01

A dipolar dipicolinate derivative, trans-dimethyl-4-[4'-(N,N-diphenylamino)-styry1]-pyridin-2,6-dicarboxylate (P-1), and a P-1based V-shaped compound, {4-[(E)-2-(2,6-dimethoxycarbonylpyridin-4-yl) vinyl]}-N-phenyl-N-{4-[(E)-2-(2,6-dimethoxycarbonylpyridin-4-yl)vinylphenyl]}aniline (P-2), with intense two-photon fluorescence emission properties were systematically investigated by using steady-state absorption and fluorescence spectroscopy, open-aperture Z-scans, and two-photon excited fluorescence (TPF). The two-photon absorption cross-section of the V-shaped compound P-2 in tetrahydrofuran (THF) was determined to be 208 GM, which represents a 6.5-fold enhancement compared with its dipolar counterpart P-1 (32 GM). Extension of the intramolecular charge transfer (ICT) in the V-shaped dipicolinate derivative has been suggested as the mechanism of enhancement. The excited state dynamics from transient absorption spectroscopy were analyzed and discussed. The formation and relaxation lifetimes of the ICT state for these dipicolinate derivatives in THF solutions were found to be several picoseconds and several hundred picoseconds, respectively. The results show an increased ICT character of the V-shaped compound and a potential application for this compound in two-photon fluorescence imaging fields.

Ultrafast responses of dipolar and V-shaped dipicolinate derivatives with potential applications in the labeling of biomolecules

Directory of Open Access Journals (Sweden)

Yaochuan Wang

2016-02-01

Full Text Available A dipolar dipicolinate derivative, trans-dimethyl-4-[4′-(N,N-diphenylamino-styry1]-pyridin-2,6-dicarboxylate (P-1, and a P-1based V-shaped compound, {4-[(E-2-(2,6-dimethoxycarbonylpyridin-4-yl vinyl]}-N-phenyl-N-{4-[(E-2-(2,6-dimethoxycarbonylpyridin-4-ylvinylphenyl]}aniline (P-2, with intense two-photon fluorescence emission properties were systematically investigated by using steady-state absorption and fluorescence spectroscopy, open-aperture Z-scans, and two-photon excited fluorescence (TPF. The two-photon absorption cross-section of the V-shaped compound P-2 in tetrahydrofuran (THF was determined to be 208 GM, which represents a 6.5-fold enhancement compared with its dipolar counterpart P-1 (32 GM. Extension of the intramolecular charge transfer (ICT in the V-shaped dipicolinate derivative has been suggested as the mechanism of enhancement. The excited state dynamics from transient absorption spectroscopy were analyzed and discussed. The formation and relaxation lifetimes of the ICT state for these dipicolinate derivatives in THF solutions were found to be several picoseconds and several hundred picoseconds, respectively. The results show an increased ICT character of the V-shaped compound and a potential application for this compound in two-photon fluorescence imaging fields.

Breakdown of the single-exchange approximation in third-order symmetry-adapted perturbation theory.

Science.gov (United States)

Lao, Ka Un; Herbert, John M

2012-03-22

We report third-order symmetry-adapted perturbation theory (SAPT) calculations for several dimers whose intermolecular interactions are dominated by induction. We demonstrate that the single-exchange approximation (SEA) employed to derive the third-order exchange-induction correction (E(exch-ind)((30))) fails to quench the attractive nature of the third-order induction (E(ind)((30))), leading to one-dimensional potential curves that become attractive rather than repulsive at short intermolecular separations. A scaling equation for (E(exch-ind)((30))), based on an exact formula for the first-order exchange correction, is introduced to approximate exchange effects beyond the SEA, and qualitatively correct potential energy curves that include third-order induction are thereby obtained. For induction-dominated systems, our results indicate that a "hybrid" SAPT approach, in which a dimer Hartree-Fock calculation is performed in order to obtain a correction for higher-order induction, is necessary not only to obtain quantitative binding energies but also to obtain qualitatively correct potential energy surfaces. These results underscore the need to develop higher-order exchange-induction formulas that go beyond the SEA. © 2012 American Chemical Society

Effect of secondary structure on the interactions of peptide T4 LYS (11-36) in mixtures of aqueous sodium chloride and 2,2,2,-Trifluoroethanol

Energy Technology Data Exchange (ETDEWEB)

Anderson, Camille O.; Spiegelberg, Susanne; Prausnitz, John M.; Blanch, Harvey W.

2001-10-01

The potential of mean force for protein-protein interactions is key to the development of a statistical-mechanical model for salt-induced protein precipitation and crystallization, and for understanding certain disease states, including cataract formation and {beta}-amyloid pathology in Alzheimer's disease. Fluorescence anisotropy provides a method for quantitative characterization of intermolecular interactions due to reversible association. Monomer-dimer equilibria for the peptide T4 LYS(11-36) were studied by fluorescence anisotropy. This peptide, derived from the {beta}-sheet region of the T4 lysozyme molecule, has the potential to form amyloid fibrils. 2,2,2-trifluoroethanol (TFE) induces a change in peptide secondary structure, and was used in aqueous solutions at concentrations from 0 to 50% (v/v) at 25 and 37 C to examine the role of peptide conformation on peptide-peptide interactions. The association constant for dimerization increased with rising TFE concentration and with falling temperature. The peptide-peptide potential of mean force was computed from these association constants. Circular-dichroism measurements showed that the secondary structure of the peptide plays an important role in these strong attractive interactions due to intermolecular hydrogen-bond formation and hydrophobic interactions.

Investigation of acetyl migrations in furanosides

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Migaud ME

2006-07-01

Full Text Available Abstract Standard reaction conditions for the desilylation of acetylated furanoside (riboside, arabinoside and xyloside derivatives facilitate acyl migration. Conditions which favour intramolecular and intermolecular mechanisms have been identified with intermolecular transesterifications taking place under mild basic conditions when intramolecular orthoester formations are disfavoured. In acetyl ribosides, acyl migration could be prevented when desilylation was catalysed by cerium ammonium nitrate.

Therapeutic potential of CAR-T cell-derived exosomes: a cell-free modality for targeted cancer therapy.

Science.gov (United States)

Tang, Xiang-Jun; Sun, Xu-Yong; Huang, Kuan-Ming; Zhang, Li; Yang, Zhuo-Shun; Zou, Dan-Dan; Wang, Bin; Warnock, Garth L; Dai, Long-Jun; Luo, Jie

2015-12-29

Chimeric antigen receptor (CAR)-based T-cell adoptive immunotherapy is a distinctively promising therapy for cancer. The engineering of CARs into T cells provides T cells with tumor-targeting capabilities and intensifies their cytotoxic activity through stimulated cell expansion and enhanced cytokine production. As a novel and potent therapeutic modality, there exists some uncontrollable processes which are the potential sources of adverse events. As an extension of this impactful modality, CAR-T cell-derived exosomes may substitute CAR-T cells to act as ultimate attackers, thereby overcoming some limitations. Exosomes retain most characteristics of parent cells and play an essential role in intercellular communications via transmitting their cargo to recipient cells. The application of CAR-T cell-derived exosomes will make this cell-based therapy more clinically controllable as it also provides a cell-free platform to diversify anticancer mediators, which responds effectively to the complexity and volatility of cancer. It is believed that the appropriate application of both cellular and exosomal platforms will make this effective treatment more practicable.

Solid state crystallisation of oligosaccharide ester derivatives

Energy Technology Data Exchange (ETDEWEB)

Wright, Elaine Ann

2002-07-01

An investigation of the solid state properties of oligosaccharide ester derivatives (OEDs) with potential applications in drug delivery has been carried out. The amorphous form of two OEDs, trehalose octa-acetate (TOAC) and 6:6'-di-({beta}-tetraacetyl glucuronyl)-hexaacetyl trehalose (TR153), was investigated as a matrix for the sustained release of active ingredients. The matrices showed a tendency to crystallise and so polymorph screens were performed to provide crystalline samples for structural analysis. The crystal structures of TOAC methanolate and TR153 acetonitrile solvate have been determined by single-crystal laboratory X-ray diffraction. TOAC methanolate crystallises in the orthorhombic space group P2{sub 1}2{sub 1}2{sub 1} with a = 15.429(18) A, b = 17.934(19) A and c = 13.518(4) A at 123 K. The structure is isomorphous with the previously reported structure of TOAC monohydrate form II. TR153 acetonitrile solvate crystallises in the monoclinic spacegroup C2 with a = 30:160(6) A, b = 11.878(3) A, c 20.6645(5) A and {beta} = 115.027 (10) deg at 123 K. The crystal structures of both TOAC methanolate and TR153 acetonitrile solvate are stabilised by complex networks of intermolecular C--H...O contacts. Two model compounds were selected for dissolution studies: diltiazem hydrochloride, as a water- soluble organic salt, and ketoprofen as a poorly water-soluble organic compound. Dissolution of both compounds from amorphous TOAC and TR153 matrices was investigated. The release of both drugs was more rapid and complete from TOAC matrices than from TR153 matrices, with both matrices showing a tendency to crystallise (devitrify) during the course of the dissolution experiments. This tendency was greater for the TOAC matrix, which transformed to the extent of ca. 100% within 48 hours. The available evidence suggests that devitrification of the matrix in contact with water produces a polycrystalline, non-monolithic structure rich in microscopic cracks and pores

Solid state crystallisation of oligosaccharide ester derivatives

International Nuclear Information System (INIS)

Wright, Elaine Ann

2002-01-01

An investigation of the solid state properties of oligosaccharide ester derivatives (OEDs) with potential applications in drug delivery has been carried out. The amorphous form of two OEDs, trehalose octa-acetate (TOAC) and 6:6'-di-(β-tetraacetyl glucuronyl)-hexaacetyl trehalose (TR153), was investigated as a matrix for the sustained release of active ingredients. The matrices showed a tendency to crystallise and so polymorph screens were performed to provide crystalline samples for structural analysis. The crystal structures of TOAC methanolate and TR153 acetonitrile solvate have been determined by single-crystal laboratory X-ray diffraction. TOAC methanolate crystallises in the orthorhombic space group P2 1 2 1 2 1 with a = 15.429(18) A, b = 17.934(19) A and c = 13.518(4) A at 123 K. The structure is isomorphous with the previously reported structure of TOAC monohydrate form II. TR153 acetonitrile solvate crystallises in the monoclinic spacegroup C2 with a = 30:160(6) A, b = 11.878(3) A, c 20.6645(5) A and β = 115.027 (10) deg at 123 K. The crystal structures of both TOAC methanolate and TR153 acetonitrile solvate are stabilised by complex networks of intermolecular C--H...O contacts. Two model compounds were selected for dissolution studies: diltiazem hydrochloride, as a water- soluble organic salt, and ketoprofen as a poorly water-soluble organic compound. Dissolution of both compounds from amorphous TOAC and TR153 matrices was investigated. The release of both drugs was more rapid and complete from TOAC matrices than from TR153 matrices, with both matrices showing a tendency to crystallise (devitrify) during the course of the dissolution experiments. This tendency was greater for the TOAC matrix, which transformed to the extent of ca. 100% within 48 hours. The available evidence suggests that devitrification of the matrix in contact with water produces a polycrystalline, non-monolithic structure rich in microscopic cracks and pores which allows diffusion of

Higher derivative analysis for the interpretation of self-potential profiles at southern part of the Nile Delta, Egypt

International Nuclear Information System (INIS)

Hafez, M.; EL-Qady, G.; Awad, S.; Elsayed, E.

2006-01-01

One of the most important, but also one of the most tedious, problems confronting the mineral industries in dealing with the sulfides and graphite is estimating the depth of a buried object from self-potential anomalies. A peat layer has been encountered in the subsurface Holocene sediments of the eastern part of the Nile Delta at depths range from 7 to 13 meters. The maximum thickness of the peat (3m) has been recorded in the southern part of the Mansoura city and it decreases gradually in a configuration parallel to Damietta branch of the Nile. To elucidate the peat layer in terms of depth and thickness, a self-potential survey was carried at Mansoura city, Nile Delta of Egypt, in terms of eight profiles. Interpretation of data was performed through the correction and processing using the derivative analysis of higher orders by means of an algorithm developed by the authors. Depth, shape factor and the optimum order of the regional components are determined. A rough estimation of the relief of the peat layer was derived. Based in the results, the depth to the peat layer varies from 11.8 up to 13.1 meters which correlates very well with the available information and the lithological data in the area. (author)

Non-covalent interactions across organic and biological subsets of chemical space: Physics-based potentials parametrized from machine learning

Science.gov (United States)

Bereau, Tristan; DiStasio, Robert A.; Tkatchenko, Alexandre; von Lilienfeld, O. Anatole

2018-06-01

Classical intermolecular potentials typically require an extensive parametrization procedure for any new compound considered. To do away with prior parametrization, we propose a combination of physics-based potentials with machine learning (ML), coined IPML, which is transferable across small neutral organic and biologically relevant molecules. ML models provide on-the-fly predictions for environment-dependent local atomic properties: electrostatic multipole coefficients (significant error reduction compared to previously reported), the population and decay rate of valence atomic densities, and polarizabilities across conformations and chemical compositions of H, C, N, and O atoms. These parameters enable accurate calculations of intermolecular contributions—electrostatics, charge penetration, repulsion, induction/polarization, and many-body dispersion. Unlike other potentials, this model is transferable in its ability to handle new molecules and conformations without explicit prior parametrization: All local atomic properties are predicted from ML, leaving only eight global parameters—optimized once and for all across compounds. We validate IPML on various gas-phase dimers at and away from equilibrium separation, where we obtain mean absolute errors between 0.4 and 0.7 kcal/mol for several chemically and conformationally diverse datasets representative of non-covalent interactions in biologically relevant molecules. We further focus on hydrogen-bonded complexes—essential but challenging due to their directional nature—where datasets of DNA base pairs and amino acids yield an extremely encouraging 1.4 kcal/mol error. Finally, and as a first look, we consider IPML for denser systems: water clusters, supramolecular host-guest complexes, and the benzene crystal.

Effective Fragment Potential Method for H-Bonding: How To Obtain Parameters for Nonrigid Fragments.

Science.gov (United States)

Dubinets, Nikita; Slipchenko, Lyudmila V

2017-07-20

Accuracy of the effective fragment potential (EFP) method was explored for describing intermolecular interaction energies in three dimers with strong H-bonded interactions, formic acid, formamide, and formamidine dimers, which are a part of HBC6 database of noncovalent interactions. Monomer geometries in these dimers change significantly as a function of intermonomer separation. Several EFP schemes were considered, in which fragment parameters were prepared for a fragment in its gas-phase geometry or recomputed for each unique fragment geometry. Additionally, a scheme in which gas-phase fragment parameters are shifted according to relaxed fragment geometries is introduced and tested. EFP data are compared against the coupled cluster with single, double, and perturbative triple excitations (CCSD(T)) method in a complete basis set (CBS) and the symmetry adapted perturbation theory (SAPT). All considered EFP schemes provide a good agreement with CCSD(T)/CBS for binding energies at equilibrium separations, with discrepancies not exceeding 2 kcal/mol. However, only the schemes that utilize relaxed fragment geometries remain qualitatively correct at shorter than equilibrium intermolecular distances. The EFP scheme with shifted parameters behaves quantitatively similar to the scheme in which parameters are recomputed for each monomer geometry and thus is recommended as a computationally efficient approach for large-scale EFP simulations of flexible systems.

Tuning the redox potential of vitamin K3 derivatives by oxidative functionalization using a Ag(i)/GO catalyst.

Science.gov (United States)

El-Hout, S I; Suzuki, H; El-Sheikh, S M; Hassan, H M A; Harraz, F A; Ibrahim, I A; El-Sharkawy, E A; Tsujimura, S; Holzinger, M; Nishina, Y

2017-08-03

We propose herein initial results to develop optimum redox mediators by the combination of computational simulation and catalytic functionalization of the core structure of vitamin K 3 . We aim to correlate the calculated energy value of the LUMO of different vitamin K 3 derivatives with their actual redox potential. For this, we optimized the catalytic alkylation of 1,4-naphthoquinones with a designed Ag(i)/GO catalyst and synthesized a series of molecules.

New chroman-4-one/thiochroman-4-one derivatives as potential anticancer agents

Directory of Open Access Journals (Sweden)

Seref Demirayak

2017-11-01

Full Text Available The synthesis of 3-[3/4-(2-aryl-2-oxoethoxyarylidene]chroman/thiochroman-4-one derivatives (1–34 and evaluation of their anticancer activities were aimed in this work. Final compounds were obtained in multistep synthesis reactions using phenol/thiophenol derivatives as starting materials. For anticancer activity evaluation, all compounds were offered to National Cancer Institute (NCI, USA and selected ones were tested against sixty human tumor cell lines derived from nine neoplastic diseases. The activity results were evaluated according to the drug screening protocol of the institute. Compounds containing thiochromanone skeleton exhibited higher anticancer activity.

Towards interpretation of intermolecular paramagnetic relaxation enhancement outside the fast exchange limit.

Science.gov (United States)

Ceccon, Alberto; Marius Clore, G; Tugarinov, Vitali

2016-09-01

In an exchanging system between major and minor species, the transverse paramagnetic relaxation enhancement rate observed on the resonances of the major species (Γ 2 (app) ) is dependent upon the exchange regime between the species. Quantitative analysis of PRE data in such systems typically assumes that the overall exchange rate k ex between the species is fast on the PRE time scale (k ex ≫ Γ2). Recently, we have characterized the kinetics of binding of the model protein ubiquitin to large (LUV) and small (SUV) unilamellar lipid-based nanoparticles or liposomes (Ceccon A, Tugarinov V, Bax A, Clore GM (2016). J Am Chem Soc 138:5789-5792). Building upon these results and taking advantage of a strong paramagnetic agent with an isotropic g-tensor, Gd(3+), we were able to measure intermolecular methyl carbon and proton PREs between paramagnetically-tagged liposomes and ubiquitin. In the limit of fast exchange (k ex ≫ Γ2) the ratio of the apparent proton to carbon methyl PREs, ((1)Hm-Γ 2 (app) )/((13)Cm-Γ 2 (app) ), is equal to the square of the ratio of the gyromagnetic ratios of the two nuclei, (γΗ/γC)(2). However, outside the fast exchange regime, under intermediate exchange conditions (e.g. when Γ2 is comparable in magnitude to k ex) the ((1)Hm-Γ 2 (app) )/((13)Cm-Γ 2 (app) ) ratio provides a reliable measure of the 'true' methyl PREs.

Size-dependent disproportionation (in 2-20 nm regime) and hybrid Bond Valence derived interatomic potentials for BaTaO2N

Science.gov (United States)

Anbalagan, Kousika; Thomas, Tiju

2018-05-01

Interatomic potentials for complex materials (like ceramic systems) are important for realistic molecular dynamics (MD) simulations. Such simulations are relevant for understanding equilibrium, transport and dynamical properties of materials, especially in the nanoregime. Here we derive a hybrid interatomic potential (based on bond valence (BV) derived Morse and Coulomb terms), for modeling a complex ceramic, barium tantalum oxynitride (BaTaO2N). This material has been chosen due to its relevance for capacitive and photoactive applications. However, the material presents processing challenges such as the emergence of non-stoichiometric phases during processing, demonstrating complex processing-property correlations. This makes MD investigations of this material both scientifically and technologically relevant. The BV based hybrid potential presented here has been used for simulating sintering of BaTaO2N nanoparticles ( 2-20 nm) under different conditions (using the relevant canonical ensemble). Notably, we show that sintering of particles of diameter 10 nm in size results in the formation of a cluster of tantalum and oxygen atoms at the interface of the BaTaO2N particles. This is in agreement with the experimental reports. The results presented here suggest that the potential proposed can be used to explore dynamical properties of BaTaO2N and related systems. This work will also open avenues for development of nanoscience-enabled aid-free sintering approaches to this and related materials.

Potential Biosignificant Interest and Surface Activity of Efficient Heterocyclic Derivatives.

Science.gov (United States)

El-Sayed, Refat; Althagafi, Ismail

2016-01-01

Some functionalized pyridine and fused system derivatives were synthesized using enaminonitrile derivative 5 as a starting material for the reaction, with various reagents under different conditions. Propoxylation of these compounds using different moles of propylene oxide (3, 5 and 7 moles) leads to a novel group of surface active agents. The antimicrobial and surface activities of the synthesized compounds were investigated. Most of the evaluated compounds proved to be active as antibacterial and antifungal agents and showed good surface activity, which makes them suitable for diverse applications such as the manufacturing of emulsifiers, cosmetics, drugs, pesticides, etc. Additionally, biodegradation testing exhibits significant breakdown within six to seven days, and hence, lowers the toxicity to human beings and becomes environmentally friendly.

Synthesis and modifications of heterocyclic derivatives of D-arabinose: potential inhibitors of glucose-6-phosphate isomerase and glucosamine-6-phosphate synthase

International Nuclear Information System (INIS)

Viana, Renato Marcio Ribeiro; Prado, Maria Auxiliadora Fontes; Alves, Ricardo Jose

2008-01-01

The synthesis of -5-(D-arabino-1,2,3,4-tetrahydroxybutyl)tetrazole and -2-(d-arabino-1,2,3,4-tetra-acetoxybutyl)-5-methyl-1,3,4-oxadiazole from d-arabinose is described. Attempts at removing the protecting groups of the oxadiazole derivative were unsuccessful, leading to products resulting from the opening of the oxadiazole ring. The unprotected tetrazole derivative was selectively phosphorylated at the primary hydroxyl group with diethyl phosphoryl chloride. The resulting 5-[d-arabino-4-(diethylphosphoryloxy)-1,2,3-trihydroxybutyl]tetrazole is a protected form of a potential inhibitor of the enzymes glucose-6-phosphate isomerase and glucosamine synthase. (author)

Design and Synthesis of Bis-amide and Hydrazide-containing Derivatives of Malonic Acid as Potential HIV-1 Integrase Inhibitors

Directory of Open Access Journals (Sweden)

Nouri Neamati

2008-10-01

Full Text Available HIV-1 integrase (IN is an attractive and validated target for the development of novel therapeutics against AIDS. In the search for new IN inhibitors, we designed and synthesized three series of bis-amide and hydrazide-containing derivatives of malonic acid. We performed a docking study to investigate the potential interactions of the title compounds with essential amino acids on the IN active site.

Conformational polymorphism and aromaticity in crystalline dibenzotetraaza[14]annulene derivatives

Science.gov (United States)

Śliwiński, Jan; Eilmes, Julita; Oleksyn, Barbara J.; Stadnicka, Katarzyna

2004-06-01

The structures of two single crystal modifications, orange and yellow, of 7,16-dibenzoyl-6,8,15,17-tetramethyl-5,14-dihydrodibenzo [b,i][1,4,8,11]tetraazacyclotetradecine were determined in room and low temperatures. The aromaticity of the 14-membered macrocyclic ring system was studied with the use of HOMA index and compared to the values calculated for the structures found in the Cambridge Structural Database System. The nature of the polymorphism of the investigated molecules was elucidated. The molecules of the orange and yellow modifications differ in the mutual orientation of the benzoyl groups. The molecular conformation in the yellow crystals is stabilized by two intramolecular hydrogen bonds, C-H⋯OC, which do not occur in the orange modification. Weak, but numerous, intermolecular bonds of this type occur in both modifications, but in the orange polymorph a π-π interaction is also observed, while in the yellow modification a C-H⋯N intermolecular bond is formed.

Impact of low oxygen tension on stemness, proliferation and differentiation potential of human adipose-derived stem cells

Energy Technology Data Exchange (ETDEWEB)

Choi, Jane Ru; Pingguan-Murphy, Belinda; Wan Abas, Wan Abu Bakar [Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia); Noor Azmi, Mat Adenan; Omar, Siti Zawiah [Department of Obstetrics and Gynaecology, Faculty of Medicine, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia); Chua, Kien Hui [Department of Physiology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur (Malaysia); Wan Safwani, Wan Kamarul Zaman, E-mail: wansafwani@um.edu.my [Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia)

2014-05-30

Highlights: • Hypoxia maintains the stemness of adipose-derived stem cells (ASCs). • ASCs show an increased proliferation rate under low oxygen tension. • Oxygen level as low as 2% enhances the chondrogenic differentiation potential of ASCs. • HIF-1α may regulate the proliferation and differentiation activities of ASCs under hypoxia. - Abstract: Adipose-derived stem cells (ASCs) have been found adapted to a specific niche with low oxygen tension (hypoxia) in the body. As an important component of this niche, oxygen tension has been known to play a critical role in the maintenance of stem cell characteristics. However, the effect of O{sub 2} tension on their functional properties has not been well determined. In this study, we investigated the effects of O{sub 2} tension on ASCs stemness, differentiation and proliferation ability. Human ASCs were cultured under normoxia (21% O{sub 2}) and hypoxia (2% O{sub 2}). We found that hypoxia increased ASC stemness marker expression and proliferation rate without altering their morphology and surface markers. Low oxygen tension further enhances the chondrogenic differentiation ability, but reduces both adipogenic and osteogenic differentiation potential. These results might be correlated with the increased expression of HIF-1α under hypoxia. Taken together, we suggest that growing ASCs under 2% O{sub 2} tension may be important in expanding ASCs effectively while maintaining their functional properties for clinical therapy, particularly for the treatment of cartilage defects.

Green One-pot Synthesis of Novel Polysubstituted Pyrazole Derivatives as Potential Antimicrobial Agents.

Science.gov (United States)

Beyzaei, Hamid; Motraghi, Zahra; Aryan, Reza; Zahedi, Mohammad Mehdi; Samzadeh-Kermani, Alireza

2017-12-01

Various biological properties of natural and synthetic pyrazole derivatives such as anti-inflammatory, antimicrobial, neuroprotective, anticonvulsant, antidepressant and anticancer activities encouraged us to propose a new, fast, green and eco-friendly procedure for the preparation of some novel 5-amino-3-(aryl substituted)-1-(2,4-dinitrophenyl)-1H-pyrazole-4-carbonitriles. They were efficiently synthesized via one-pot two-step process reaction of malononitrile, 2,4-dinitrophenylhydrazine and different benzaldehydes in deep eutectic solvent (DES) glycerol/potassium carbonate. The products yield and reaction times were considerably improved in the presence of applied DES. Antibacterial effects of all newly synthesized pyrazoles in comparison with several common antibiotics were evaluated against a variety of Gram-positive and Gram-negative pathogenic bacteria. In addition to, their inhibitory activities on three fungi were compared to some current antifungal agents. The moderate to good antimicrobial potentials particularly against fungi were observed in the major heterocyclic compounds according to the IZD, MIC, MBC and MFC results.

Effect of water on the local electric potential of simulated ionic micelles

Energy Technology Data Exchange (ETDEWEB)

Brodskaya, Elena N.; Vanin, Alexander A., E-mail: alexvanin@yandex.ru [Institute of Chemistry, St. Petersburg State University, Universitetskiy pr. 26, Petrodvoretz, St. Petersburg 198504 (Russian Federation)

2015-07-28

Ionic micelles in an aqueous solution containing single-charged counter-ions have been simulated by molecular dynamics. For both cationic and anionic micelles, it has been demonstrated that explicit description of solvent has strong effect on the micelle’s electric field. The sign of the local charge alters in the immediate vicinity of the micellar crown and the electric potential varies nonmonotonically. Two micelle models have been examined: the hybrid model with a rigid hydrocarbon core and the atomistic model. For three molecular models of water (Simple Point Charge model (SPC), Transferable Intermolecular Potential 5- Points (TIP5P) and two-centered S2), the results have been compared with those for the continuum solvent model. The orientational ordering of solvent molecules has strong effect on the local electric field surprisingly far from the micelle surface.

An efficient method for the determination of fourth virial coefficient with Lennard-Jones (12-6) potential and its application

Energy Technology Data Exchange (ETDEWEB)

Mamedov, Bahtiyar A. [Department of Physics, Gaziosmanpaşa University, 60250, Tokat (Turkey); Somuncu, Elif; Askerov, Iskender M. [Department of Physics, Giresun University, Giresun (Turkey)

2016-08-10

In this work, a new theoretical approach is proposed for calculating fourth virial coefficient with Lennard-Jones potential. The established algorithm can be used to evaluate the thermodynamics properties and the intermolecular interaction potentials of liquids and gases with an improved accuracy. Note that the evaluation of the high-order virial coefficients is very valuable for accurate calculation of thermodynamic parameters. By using the suggested method, the fourth virial coefficient of CH{sub 4}, Ar, C{sub 2}H{sub 6} and SF{sub 6} molecules are evaluated. The calculation results are useful for accurate interpretation of the experimental data and of the determination of related physical properties.

Mössbauer spectroscopic and powder X-ray diffraction studies on incorporation of gaseous organic molecules into intermolecular nano-voids of mixed-valence trinuclear iron pentafluorobenzoate complex

International Nuclear Information System (INIS)

Sakai, Yoichi; Onaka, Satoru; Ogiso, Ryo; Takayama, Tsutomu; Takahashi, Masashi; Nakamoto, Tadahiro

2013-01-01

Incorporation of gaseous organic molecules into polycrystalline mixed-valence trinuclear iron (Fe 3+ ,Fe 3+ ,Fe 2+ ) pentafluorobenzoate complex Fe 3 O(C 6 F 5 COO) 6 (C 5 H 5 N) 3 with intermolecular nano-voids was studied by 57 Fe-Mössbauer spectroscopic and powder XRD measurements. Organic-molecule incorporation was mainly chased by using iron-valence fluctuation observed in a Mössbauer spectrum, and also researched supportively by a powder XRD technique. (author)

Potential of laryngeal muscle regeneration using induced pluripotent stem cell-derived skeletal muscle cells.

Science.gov (United States)

Dirja, Bayu Tirta; Yoshie, Susumu; Ikeda, Masakazu; Imaizumi, Mitsuyoshi; Nakamura, Ryosuke; Otsuki, Koshi; Nomoto, Yukio; Wada, Ikuo; Hazama, Akihiro; Omori, Koichi

2016-01-01

Conclusion Induced pluripotent stem (iPS) cells may be a new potential cell source for laryngeal muscle regeneration in the treatment of vocal fold atrophy after recurrent laryngeal nerve paralysis. Objectives Unilateral vocal fold paralysis can lead to degeneration, atrophy, and loss of force of the thyroarytenoid muscle. At present, there are some treatments such as thyroplasty, arytenoid adduction, and vocal fold injection. However, such treatments cannot restore reduced mass of the thyroarytenoid muscle. iPS cells have been recognized as supplying a potential resource for cell transplantation. The aim of this study was to assess the effectiveness of the use of iPS cells for the regeneration of laryngeal muscle through the evaluation of both in vitro and in vivo experiments. Methods Skeletal muscle cells were generated from tdTomato-labeled iPS cells using embryoid body formation. Differentiation into skeletal muscle cells was analyzed by gene expression and immunocytochemistry. The tdTomato-labeled iPS cell-derived skeletal muscle cells were transplanted into the left atrophied thyroarytenoid muscle. To evaluate the engraftment of these cells after transplantation, immunohistochemistry was performed. Results The tdTomato-labeled iPS cells were successfully differentiated into skeletal muscle cells through an in vitro experiment. These cells survived in the atrophied thyroarytenoid muscle after transplantation.

Analysis and Ranking of Protein-Protein Docking Models Using Inter-Residue Contacts and Inter-Molecular Contact Maps

KAUST Repository

Oliva, Romina; Chermak, Edrisse; Cavallo, Luigi

2015-01-01

In view of the increasing interest both in inhibitors of protein-protein interactions and in protein drugs themselves, analysis of the three-dimensional structure of protein-protein complexes is assuming greater relevance in drug design. In the many cases where an experimental structure is not available, protein-protein docking becomes the method of choice for predicting the arrangement of the complex. However, reliably scoring protein-protein docking poses is still an unsolved problem. As a consequence, the screening of many docking models is usually required in the analysis step, to possibly single out the correct ones. Here, making use of exemplary cases, we review our recently introduced methods for the analysis of protein complex structures and for the scoring of protein docking poses, based on the use of inter-residue contacts and their visualization in inter-molecular contact maps. We also show that the ensemble of tools we developed can be used in the context of rational drug design targeting protein-protein interactions.

Analysis and Ranking of Protein-Protein Docking Models Using Inter-Residue Contacts and Inter-Molecular Contact Maps

KAUST Repository

Oliva, Romina

2015-07-01

In view of the increasing interest both in inhibitors of protein-protein interactions and in protein drugs themselves, analysis of the three-dimensional structure of protein-protein complexes is assuming greater relevance in drug design. In the many cases where an experimental structure is not available, protein-protein docking becomes the method of choice for predicting the arrangement of the complex. However, reliably scoring protein-protein docking poses is still an unsolved problem. As a consequence, the screening of many docking models is usually required in the analysis step, to possibly single out the correct ones. Here, making use of exemplary cases, we review our recently introduced methods for the analysis of protein complex structures and for the scoring of protein docking poses, based on the use of inter-residue contacts and their visualization in inter-molecular contact maps. We also show that the ensemble of tools we developed can be used in the context of rational drug design targeting protein-protein interactions.

Removal potential of toxic 2378-substituted PCDD/F from incinerator flue gases by waste-derived activated carbons.

Science.gov (United States)

Hajizadeh, Yaghoub; Onwudili, Jude A; Williams, Paul T

2011-06-01

The application of activated carbons has become a commonly used emission control protocol for the removal or adsorption of persistent organic pollutants from the flue gas streams of waste incinerators. In this study, the 2378-substituted PCDD/F removal efficiency of three types of activated carbons derived from the pyrolysis of refuse derived fuel, textile waste and scrap tyre was investigated and compared with that of a commercial carbon. Experiments were carried out in a laboratory scale fixed-bed reactor under a simulated flue gas at 275°C with a reaction period of four days. The PCDD/F in the solid matrices and exhaust gas, were analyzed using gas chromatography coupled with a triple quadrupole mass spectrometer. In the absence of activated carbon adsorbent, there was a significant increase in the concentration of toxic PCDD/F produced in the reacted flyash, reaching up to 6.6 times higher than in the raw flyash. In addition, there was a substantial release of PCDD/F into the gas phase, which was found in the flue gas trapping system. By application of the different commercial, refuse derived fuel, textile and tyre activated carbons the total PCDD/F toxic equivalent removal efficiencies in the exhaust gas stream were 58%, 57%, 64% and 52%, respectively. In general, the removal of the PCDDs was much higher with an average of 85% compared to PCDFs at 41%. Analysis of the reacted activated carbons showed that there was some formation of PCDD/F, for instance, a total of 60.6 μg I-TEQ kg(-1) toxic PCDD/F was formed in the refuse derived fuel activated carbon compared to 34 μg I-TEQ kg(-1) in the commercial activated carbon. The activated carbons derived from the pyrolysis of waste, therefore, showed good potential as a control material for PCDD/F emissions in waste incinerator flue gases. Copyright © 2011 Elsevier Ltd. All rights reserved.

Quantum chemical analysis of potential anti-Parkinson agents

Indian Academy of Sciences (India)

Intermolecular binding energy components could not be analyzed by docking and due to this .... Cluster analysis was performed on the docked results with regard to RMS ... gard, docking simulation is a key tool in structural mo- lecular biology ...

Study of intermolecular interactions in binary mixtures of 2-(dimethylamino)ethanol with methanol and ethanol at various temperatures

International Nuclear Information System (INIS)

Pandey, Puneet Kumar; Pandey, Vrijesh Kumar; Awasthi, Anjali; Nain, Anil Kumar; Awasthi, Aashees

2014-01-01

Graphical abstract: The densities and ultrasonic speeds of the binary mixtures over the entire composition range were measured at various temperatures at atmospheric pressure. The excess molar volumes, isentropic compressibilities, and molar isentropic compressions have been calculated. The variations of these parameters with composition and temperature are discussed. The IR spectra were recorded they further supported the conclusion drawn from excess parameters, which indicates the presence of intermolecular hydrogen bonding between the oxygen atom of DMAE molecules and hydrogen atom of methanol and ethanol molecules in these mixtures.. - Highlights: • The study reports density and ultrasonic velocity data of 2-(dimethylamino)ethanol + methanol/ethanol mixtures. • To elucidate the interactions in 2-(dimethylamino)ethanol + methanol/ethanol binary mixtures. • Provides information on nature and relative strength of interactions in these mixtures. • Correlates physicochemical properties with interactions in these mixtures. - Abstract: The densities, ρ and ultrasonic speeds, u of the binary mixtures of 2-(dimethylamino)ethanol (DMAE) with methanol/ethanol, including those of pure liquids, over the entire composition range were measured at 298.15, 308.15 and 318.15 K. From the experimental data, the excess molar volumes, V m E and excess isentropic compressibilities, κ s E have been calculated. The excess partial molar volumes, V ¯ m,1 E and V ¯ m,2 E and excess partial molar isentropic compressions, K ¯ s,m,1 E and K ¯ s,m,2 E over the whole composition range; and partial molar volumes, V ¯ m,1 ° and V ¯ m,2 ° , partial molar isentropic compressions, K ¯ s,m,1 ° and K ¯ s,m,2 ° , excess partial molar volumes, V ¯ m,1 °E and V ¯ m,2 °E , and excess partial molar isentropic compressions, K ¯ s,m,1 °E and K ¯ s,m,2 °E at infinite dilution have also been calculated. The variations of these parameters with composition and temperature are

A potential pro-anagogic cell therapy with human placenta-derived mesenchymal cells

International Nuclear Information System (INIS)

Nishishita, Toshihide; Ouchi, Kunie; Zhang, Xiaohong; Inoue, Mariko; Inazawa, Takeshi; Yoshiura, Kenta; Kuwabara, Koichiro; Nakaoka, Takashi; Watanabe, Nobukazu; Igura, Koichi; Takahashi, Tsuneo A.; Yamashita, Naohide

2004-01-01

Recently several strategies to treat ischemic diseases have been proposed but the ideal way has to be determined. We explored whether human placenta-derived mesenchymal cells (hPDMCs) can be used for this purpose because placenta is very rich in vessels. First, production of human vascular endothelial growth factor (hVEGF) from hPDMCs was examined. The amount of hVEGF secreted by hPDMCs was similar to the amount produced by HeLa cells. hVEGF was barely detected in human umbilical vein endothelial cells (hUVECs) or human peripheral blood mononuclear cells. hVEGF secreted from hPDMCs stimulated the proliferation of hUVECs, indicating its biological activity. Transplantation of hPDMCs to the ischemic limbs of NOD/Shi-scid mice significantly improved the blood flow of the affected limbs. Blood vessel formation was more prominently observed in the limbs of treated mice as compared to the control mice. Real-time RT-PCR revealed that hPDMCs produced hVEGF for at least 7 days after transplantation. Thus, transplantation of hPDMCs could potentially be a promising treatment for human ischemic diseases

MAu2GeS4-Chalcogel (M = Co, Ni): Heterogeneous Intra- and Intermolecular Hydroamination Catalysts

KAUST Repository

Davaasuren, Bambar

2017-08-08

High surface area macroporous chalcogenide aerogels (chalcogels) MAu2GeS4 (M = Co, Ni) were prepared from K2Au2GeS4 precursor and Co(OAc)2 or NiCl2 by one-pot sol-gel metathesis reactions in aqueous media. The MAu2GeS4-chalcogels were screened for catalytic intramolecular hydroamination of 4-pentyn-1-amine substrate at different temperatures. 87% and 58% conversion was achieved at 100 °C, using CoAu2GeS4- and NiAu2GeS4-chalcogels respectively, and the reaction kinetics follows the first order. It was established that the catalytic performance of the aerogels is associated with the M(2+) centers present in the structure. Intermolecular hydroamination of aniline with 1-R-4-ethynylbenzene (R = -H, -OCH3, -Br, -F) was carried out at 100 °C using CoAu2GeS4-chalcogel catalyst, due to its promising catalytic performance. The CoAu2GeS4-chalcogel regioselectively converted the pair of substrates to respective Markovnikov products, (E)-1-(4-R-phenyl)-N-phenylethan-1-imine, with 38% to 60% conversion.

MAu2GeS4-Chalcogel (M = Co, Ni): Heterogeneous Intra- and Intermolecular Hydroamination Catalysts

KAUST Repository

Davaasuren, Bambar; Emwas, Abdul-Hamid M.; Rothenberger, Alexander

2017-01-01

High surface area macroporous chalcogenide aerogels (chalcogels) MAu2GeS4 (M = Co, Ni) were prepared from K2Au2GeS4 precursor and Co(OAc)2 or NiCl2 by one-pot sol-gel metathesis reactions in aqueous media. The MAu2GeS4-chalcogels were screened for catalytic intramolecular hydroamination of 4-pentyn-1-amine substrate at different temperatures. 87% and 58% conversion was achieved at 100 °C, using CoAu2GeS4- and NiAu2GeS4-chalcogels respectively, and the reaction kinetics follows the first order. It was established that the catalytic performance of the aerogels is associated with the M(2+) centers present in the structure. Intermolecular hydroamination of aniline with 1-R-4-ethynylbenzene (R = -H, -OCH3, -Br, -F) was carried out at 100 °C using CoAu2GeS4-chalcogel catalyst, due to its promising catalytic performance. The CoAu2GeS4-chalcogel regioselectively converted the pair of substrates to respective Markovnikov products, (E)-1-(4-R-phenyl)-N-phenylethan-1-imine, with 38% to 60% conversion.

In vitro fermentation and prebiotic potential of novel low molecular weight polysaccharides derived from agar and alginate seaweeds.

Science.gov (United States)

Ramnani, Priya; Chitarrari, Roberto; Tuohy, Kieran; Grant, John; Hotchkiss, Sarah; Philp, Kevin; Campbell, Ross; Gill, Chris; Rowland, Ian

2012-02-01

Fermentation properties and prebiotic potential of novel low molecular weight polysaccharides (LMWPs) derived from agar and alginate bearing seaweeds was investigated. Ten LMWPs were supplemented to pH, temperature controlled anaerobic batch cultures inoculated with human feces from three donors, in triplicate. Microbiota changes were monitored using Fluorescent in-situ hybridization and short chain fatty acids, the fermentation end products were analysed using gas chromatography. Of the ten LMWPs tested, Gelidium seaweed CC2253 of molecular weight 64.64 KDa showed a significant increase in bifidobacterial populations from log(10) 8.06 at 0 h to log(10) 8.55 at 24 h (p = 0.018). For total bacterial populations, alginate powder CC2238 produced a significant increase from log(10) 9.01 at 0 h to log(10) 9.58 at 24 h (p = 0.032). No changes were observed in the other bacterial groups tested viz. Bacteroides, Lactobacilli/Enterococci, Eubacterium rectale/Clostridium coccoides and Clostridium histolyticum. The polysaccharides also showed significant increases in total SCFA production, particularly acetic and propionic acids, indicating that they were readily fermented. In conclusion, some LMWPs derived from agar and alginate bearing seaweeds were fermented by gut bacteria and exhibited potential to be used a novel source of prebiotics. Copyright © 2011 Elsevier Ltd. All rights reserved.

Synthesis, crystal structure, vibrational spectra and theoretical calculations of quantum chemistry of a potential antimicrobial Meldrum's acid derivative

Science.gov (United States)

Campelo, M. J. M.; Freire, P. T. C.; Mendes Filho, J.; de Toledo, T. A.; Teixeira, A. M. R.; da Silva, L. E.; Bento, R. R. F.; Faria, J. L. B.; Pizani, P. S.; Gusmão, G. O. M.; Coutinho, H. D. M.; Oliveira, M. T. A.

2017-10-01

A new derivative of Meldrum's acid 5-((5-chloropyridin-2-ylamino)methylene)-2,2-dimethyl-1,3-dioxane-4,6-dione (CYMM) of molecular formula C12H11ClN2O4 was synthesized and structurally characterized using single crystal X-ray diffraction technique. The vibrational properties of the crystal were studied by Fourier Transform infrared (FT-IR), Fourier Transform Raman (FT-Raman) techniques and theoretical calculations of quantum chemistry using Density functional theory (DFT) and Density functional perturbation theory (DFPT). A comparison with experimental spectra allowed the assignment of all the normal modes. The descriptions of the normal modes were carried by means of potential energy distribution (PED). Additionally, analysis of the antimicrobial activity and antibiotic resistance modulatory activity was carried out to evaluate the antibacterial potential of the CYMM.

Microwave Assisted Synthesis of Some New Heterocyclic Spiro-Derivatives with Potential Antimicrobial and Antioxidant Activity

Directory of Open Access Journals (Sweden)

Mohamed Mohamed Youssef

2010-12-01

Full Text Available Homophthalic anhydride reacts with different aromatic amines to produce N-substituted homophthalimides. Bromination of the latter produces 4,4-dibromo-homophthalimide derivatives that can be used as precursors for spiro-derivatives. The dibromo derivatives react with different binucleophilic reagents to produce several spiro-isoquinoline derivatives. Reaction of the dibromo derivatives with malononitrile produces dicyanomethylene derivatives which react with different binucleophiles to produce new spiro-derivatives. Structures of the newly synthesized compounds are proved using spectroscopic methods such as IR, 1H-NMR and 13C-NMR. The newly synthesized compounds were tested for their antimicrobial and antioxidant activities, showing weak or no antimicrobial activity. On the other hand select compounds showed promising antioxidant activities.

Generalized magnetic Rosenbluth potentials

International Nuclear Information System (INIS)

Hassan, M.H.A.

1977-12-01

It is shown that the coefficients of friction and diffusion of the magnetized Balescu-Lenard equation describing the interaction of ion test particles with electron field particles can be derived from two scalar potentials, which reduce to the potentials derived previously when wave effects are neglected. The parts of the potentials describing ''wave effects'' are evaluated explicitly in the case of Maxwellian electrons and the results are compared with the unmagnetized Rosenbluth potentials. The correction is dominant when eta=Ωsub(e)/ωsub(e)(>)1

CPM Is a Useful Cell Surface Marker to Isolate Expandable Bi-Potential Liver Progenitor Cells Derived from Human iPS Cells.

Science.gov (United States)

Kido, Taketomo; Koui, Yuta; Suzuki, Kaori; Kobayashi, Ayaka; Miura, Yasushi; Chern, Edward Y; Tanaka, Minoru; Miyajima, Atsushi

2015-10-13

To develop a culture system for large-scale production of mature hepatocytes, liver progenitor cells (LPCs) with a high proliferation potential would be advantageous. We have found that carboxypeptidase M (CPM) is highly expressed in embryonic LPCs, hepatoblasts, while its expression is decreased along with hepatic maturation. Consistently, CPM expression was transiently induced during hepatic specification from human-induced pluripotent stem cells (hiPSCs). CPM(+) cells isolated from differentiated hiPSCs at the immature hepatocyte stage proliferated extensively in vitro and expressed a set of genes that were typical of hepatoblasts. Moreover, the CPM(+) cells exhibited a mature hepatocyte phenotype after induction of hepatic maturation and also underwent cholangiocytic differentiation in a three-dimensional culture system. These results indicated that hiPSC-derived CPM(+) cells share the characteristics of LPCs, with the potential to proliferate and differentiate bi-directionally. Thus, CPM is a useful marker for isolating hiPSC-derived LPCs, which allows development of a large-scale culture system for producing hepatocytes and cholangiocytes. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Intermolecular Dehydrative Coupling Reaction of Arylketones with Cyclic Alkenes Catalyzed by a Well-Defined Cationic Ruthenium-Hydride Complex: A Novel Ketone Olefination Method via Vinyl C–H Bond Activation

Science.gov (United States)

Yi, Chae S.; Lee, Do W.

2010-01-01

Summary The cationic ruthenium-hydride complex [(η6-C6H6)(PCy3)(CO)RuH]+BF4− was found to be a highly effective catalyst for the intermolecular olefination reaction of arylketones with cycloalkenes. The preliminary mechanistic analysis revealed that electrophilic ruthenium-vinyl complex is the key species for mediating both vinyl C–H bond activation and the dehydrative olefination steps of the coupling reaction. PMID:20567607

The role of the ion-molecule and molecule-molecule interactions in the formation of the two-ion average force interaction potential

CERN Document Server

Ajrian, E A; Sidorenko, S N

2002-01-01

The effect of the ion-molecule and intermolecular interactions on the formation of inter-ion average force potentials is investigated within the framework of a classical ion-dipole model of electrolyte solutions. These potentials are shown to possess the Coulomb asymptotics at large distances while in the region of mean distances they reveal creation and disintegration of solvent-shared ion pairs. The calculation results provide a qualitatively authentic physical picture which is experimentally observed in strong electrolytes solutions. In particular, an increased interaction between an ion and a molecule enhances formation of ion pairs in which the ions are separated by one solvent molecule

4-Aminoquinoline derivatives

DEFF Research Database (Denmark)

Singh, Shailja; Agarwal, Drishti; Sharma, Kumkum

2016-01-01

and found them to be effective against Plasmodium falciparum under in vitro conditions. Further, we selected four most active derivatives 1m, 1o, 2c and 2j and evaluated their antimalarial potential against Plasmodium berghei in vivo. These 4-aminoquinolines cured BALB/c mice infected with P. berghei......Synthetic quinoline derivatives continue to be considered as candidates for new drug discovery if they act against CQ-resistant strains of malaria even after the widespread emergence of resistance to CQ. In this study, we explored the activities of two series of new 4-aminoquinoline derivatives...... for structure activity relationship to find lead molecules for treating multidrug-resistant Plasmodium falciparum and Plasmodium vivax....

Probing Intermolecular Electron Delocalization in Dimer Radical Anions by Vibrational Spectroscopy

International Nuclear Information System (INIS)

Mani, Tomoyasu; Brookhaven National Laboratory; Grills, David C.

2017-01-01

Delocalization of charges is one of the factors controlling charge transport in conjugated molecules. It is considered to play an important role in the performance of a wide range of molecular technologies, including organic solar cells and organic electronics. Dimerization reactions are well-suited as a model to investigate intermolecular spatial delocalization of charges. And while dimerization reactions of radical cations are well investigated, studies on radical anions are still scarce. Upon dimerization of radical anions with neutral counterparts, an electron is considered to delocalize over the two molecules. By using time-resolved infrared (TRIR) detection coupled with pulse radiolysis, we show that radical anions of 4-n-hexyl-4'-cyanobiphenyl (6CB) undergo such dimerization reactions, with an electron equally delocalized over the two molecules. We have recently demonstrated that nitrile ν(C≡N) vibrations respond to the degree of electron localization of nitrile-substituted anions: we can quantify the changes in the electronic charges from the neutral to the anion states in the nitriles by monitoring the ν(C≡N) IR shifts. In the first part of this article, we show that the sensitivity of the ν(C≡N) IR shifts does not depend on solvent polarity. In the second part, we describe how probing the shifts of the nitrile IR vibrational band unambiguously confirms the formation of dimer radical anions, with K dim = 3 × 10 4 M –1 . IR findings are corroborated by electronic absorption spectroscopy and electronic structure calculations. We find that the presence of a hexyl chain and the formation of π–π interactions are both crucial for dimerization of radical anions of 6CB with neutral 6CB. Our study provides clear evidence of spatial delocalization of electrons over two molecular fragments.

Effect of temperature dependence of the Langmuir constant molecular pair potentials on gas hydrates formation mechanism

Energy Technology Data Exchange (ETDEWEB)

Mokhtari, B.; Enayati, M. [Iranian Offshore Oil Co., Tehran (Iran, Islamic Republic of); Heidaryan, E. [Islamic Azad Univ., Tehran (Iran, Islamic Republic of). Masjidosolayman Branch

2008-07-01

Theoretical methods show that crystalline hydrates can form from single-phase systems consisting of both vapor water with gaseous hydrate former and liquid water with dissolved hydrate former. Two phase systems consist of both liquid water with gaseous hydrate former and with liquid hydrate former on the surface. This paper presented a Langmuir constant related model for the prediction of equilibrium pressures and cage occupancies of pure component hydrates. Intermolecular potentials were fit to quantum mechanical energies to obtain the Langmuir constants, which differed from the procedure utilized with the vdWP model. The paper described the experimental method and model calculations. This included the Fugacity model and Van der Waals and Platteeuw model. The paper also discussed pair potential of non-spherical molecules, including the multicentre (site-site) potential; Gaussian overlap potential; Lennard-Jones potential; and Kihara generalized pair potential. It was concluded that fraction of occupied cavities is a function of pair potentials between hard core and empty hydrate lattice. These pair potentials could be calculated from some model as Kihara cell potential, Gaussian potential, Lennard-Jones potential and multicentre pair potential. 49 refs., 3 figs.

In Silico Screening and Designing Synthesis of Cinchona Alkaloids Derivatives as Potential Anticancer

Directory of Open Access Journals (Sweden)

Muhammad Hanafi

2017-06-01

Full Text Available P-glycoprotein (P-gp resistance in cancer cells decreases intracellular accumulation of various anticancer drugs. This multidrug resistance (MDR protein can be modulated by a number of non-cytotoxic drugs. We have screened 30 chincona alkaloids derivatives as a potent P-gp inhibitor agent in silico. Hereby, we report the highest potential inhibitions of P-gp is Cinchonidine isobutanoate through molecular docking approach. with affinity energy -8.6 kcal/mol and inhibition constant, Ki is 4.89 x 10-7 M. Cinchonidine isobutanoate is also known has molecular weight below 500, Log P value 3.5, which is indicated violation free of Lipinski`s rule of five. Thus, Cinchonidine isobutanoate is the most potent compound as anticancer compare to other Cinchona alkaloids. Ultimately, we design Cinchonidine isobutanoate for further lead synthesis by using DBSA, act as a combined Brønsted acid-surfactant-catalyst (BASC to obtain high concentration of organic product by forming micellar aggregates which is very powerful catalytic application in water environment.

Tuberculosis: finding a new potential antimycobacterium derivative in a aldehyde-arylhydrazone-oxoquinoline series.

Science.gov (United States)

da C Santos, Fernanda; Castro, Helena C; Lourenço, Maria Cristina S; Abreu, Paula A; Batalha, Pedro N; Cunha, Anna C; Carvalho, Guilherme S L; Rodrigues, Carlos R; Medeiros, Cid A; Souza, Simone D; Ferreira, Vitor F; de Souza, Maria C B V

2012-10-01

Tuberculosis (TB) is a contagious disease caused by Mycobacterium tuberculosis, which remains a serious public health problem. The emergence of resistant bacterial strains has continuously increased and new treatment options are currently in need. In this work, we identified a new potential aldehyde-arylhydrazone-oxoquinoline derivative (4e) with interesting chemical structural features that may be important for designing new anti-TB agents. This 1-ethyl-N'-[(1E)-(5-nitro-2-furyl)methylene]-4-oxo-1,4-dihydroquinoline-3-carbohydrazide (4e) presented an in vitro active profile against M. tuberculosis H37Rv strain (minimum inhibitory concentration, MIC = 6.25 μg/mL) better than other acylhydrazones described in the literature (MIC = 12.5 μg/mL) and close to other antitubercular agents currently on the market. The theoretical analysis showed the importance of several structural features that together with the 5-nitro-2-furyl group generated this active compound (4e). This new compound and the analysis of its molecular properties may be useful for designing new and more efficient antibacterial drugs.

An In Vitro Potency Assay for Monitoring the Immunomodulatory Potential of Stromal Cell-Derived Extracellular Vesicles

Directory of Open Access Journals (Sweden)

Karin Pachler

2017-07-01

Full Text Available The regenerative and immunomodulatory activity of mesenchymal stromal cells (MSCs is partially mediated by secreted vesicular factors. Extracellular vesicles (EVs exocytosed by MSCs are gaining increased attention as prospective non-cellular therapeutics for a variety of diseases. However, the lack of suitable in vitro assays to monitor the therapeutic potential of EVs currently restricts their application in clinical studies. We have evaluated a dual in vitro immunomodulation potency assay that reproducibly reports the inhibitory effect of MSCs on induced T-cell proliferation and the alloantigen-driven mixed leukocyte reaction of pooled peripheral blood mononuclear cells in a dose-dependent manner. Phytohemagglutinin-stimulated T-cell proliferation was inhibited by MSC-derived EVs in a dose-dependent manner comparable to MSCs. In contrast, inhibition of alloantigen-driven mixed leukocyte reaction was only observed for MSCs, but not for EVs. Our results support the application of a cell-based in vitro potency assay for reproducibly determining the immunomodulatory potential of EVs. Validation of this assay can help establish reliable release criteria for EVs for future clinical studies.

Proton tunnelling in intermolecular hydrogen bonds

Energy Technology Data Exchange (ETDEWEB)

Horsewill, A J [Nottingham Univ. (United Kingdom); Johnson, M R [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France); Trommsdorff, H P [Grenoble-1 Univ., 38 (France)

1997-04-01

The wavefunctions of particles extend beyond the classically accessible regions of potential energy-surfaces (PES). A manifestation of this partial delocalization is the quantum-mechanical tunneling effect which enables a particle to escape from a metastable potential-well. Tunnelling is most important for the lightest atoms, so that the determination of its contribution to proton transfer, one of the most fundamental chemical reactions, is an important issue. QENS and NMR techniques have been employed to study the motion of protons in the hydrogen bond of benzoic-acid crystals, a system which has emerged as a particularly suitable model since proton transfer occurs in a near symmetric double-well potential. The influence of quantum tunnelling was revealed and investigated in these experiments. This work provides an experimental benchmark for theoretical descriptions of translational proton-tunnelling. (author). 7 refs.

Synthesis, Spectroscopic Characterization and Biological Activities of Transition Metal Complexes Derived from a Tridentate Schiff Base

Directory of Open Access Journals (Sweden)

J. Senthil Kumaran

2013-01-01

Full Text Available A new series of Cu (II, Ni (II, Co (II and Zn (II complexes have been synthesized from the Schiff base derived from 4-hydroxy-3-methoxybenzylidine-4-aminoantipyrine and 2-aminophenol. The structural features have been determined from their elemental analysis, magnetic susceptibility, molar conductance, Mass, IR, UV-Vis, 1H-NMR, 13C-NMR and ESR spectral studies. The redox behavior of the copper complex has been studied by cyclic voltammetry. The data confirm that the complexes have composition of ML2 type. The electronic absorption spectral data of the complexes propose an octahedral geometry around the central metal ion. All the metal complexes with DNA structure were guided by the presence of inter-molecular C–H⋯O and C–H⋯N hydrogen bonds. The biological activity of the synthesized compounds were tested against the bacterial species such as Bacillus subtilis, Staphylococcus aureus, Proteus vulgaris and fungal species such as Candida albicans by the well-diffusion method.

Septipyridines as conformationally controlled substitutes for inaccessible bis(terpyridine-derived oligopyridines in two-dimensional self-assembly

Directory of Open Access Journals (Sweden)

Daniel Caterbow

2011-07-01

Full Text Available The position of the peripheral nitrogen atoms in bis(terpyridine-derived oligopyridines (BTPs has a strong impact on their self-assembly behavior at the liquid/HOPG (highly oriented pyrolytic graphite interface. The intermolecular hydrogen bonding interactions in these peripheral pyridine units show specific 2D structures for each BTP isomer. From nine possible constitutional isomers only four have been described in the literature. The synthesis and self-assembling behavior of an additional isomer is presented here, but the remaining four members of the series are synthetically inaccessible. The self-assembling properties of three of the missing four BTP isomers can be mimicked by making use of the energetically preferred N–C–C–N transoid conformation between 2,2'-bipyridine subunits in a new class of so-called septipyridines. The structures are investigated by scanning tunneling microscopy (STM and a combination of force-field and first-principles electronic structure calculations.

The potential effect of differential ambient and deployment chamber temperatures on PRC derived sampling rates with polyurethane foam (PUF) passive air samplers

Energy Technology Data Exchange (ETDEWEB)

Kennedy, Karen, E-mail: k.kennedy@uq.edu.a [University of Queensland, EnTox (National Research Centre for Environmental Toxicology), 39 Kessels Rd., Coopers Plains QLD 4108 (Australia); Hawker, Darryl W. [Griffith University, School of Environment, Nathan QLD 4111 (Australia); Bartkow, Michael E. [University of Queensland, EnTox (National Research Centre for Environmental Toxicology), 39 Kessels Rd., Coopers Plains QLD 4108 (Australia); Carter, Steve [Queensland Health Forensic and Scientific Services, Coopers Plains QLD 4108 (Australia); Ishikawa, Yukari; Mueller, Jochen F. [University of Queensland, EnTox (National Research Centre for Environmental Toxicology), 39 Kessels Rd., Coopers Plains QLD 4108 (Australia)

2010-01-15

Performance reference compound (PRC) derived sampling rates were determined for polyurethane foam (PUF) passive air samplers in both sub-tropical and temperate locations across Australia. These estimates were on average a factor of 2.7 times higher in summer than winter. The known effects of wind speed and temperature on mass transfer coefficients could not account for this observation. Sampling rates are often derived using ambient temperatures, not the actual temperatures within deployment chambers. If deployment chamber temperatures are in fact higher than ambient temperatures, estimated sampler-air partition coefficients would be greater than actual partition coefficients resulting in an overestimation of PRC derived sampling rates. Sampling rates determined under measured ambient temperatures and estimated deployment chamber temperatures in summer ranged from 7.1 to 10 m{sup 3} day{sup -1} and 2.2-6.8 m{sup 3} day{sup -1} respectively. These results suggest that potential differences between ambient and deployment chamber temperatures should be considered when deriving PRC-based sampling rates. - Internal deployment chamber temperatures rather than ambient temperatures may be required to accurately estimate PRC-based sampling rates.

Synthesis and evaluation of two novel 2-nitroimidazole derivatives as potential PET radioligands for tumor imaging

Energy Technology Data Exchange (ETDEWEB)

Zha Zhihao; Zhu Lin [Key Laboratory of Radiopharmaceuticals, Beijing Normal University, Ministry of Education, Beijing 100875 (China); Department of Radiology, University of Pennsylvania, Philadelphia, PA 19014 (United States); Liu Yajing; Du Fenghua; Gan Hongmei; Qiao Jinping [Key Laboratory of Radiopharmaceuticals, Beijing Normal University, Ministry of Education, Beijing 100875 (China); Kung, Hank F., E-mail: kunghf@gmail.co [Key Laboratory of Radiopharmaceuticals, Beijing Normal University, Ministry of Education, Beijing 100875 (China); Department of Radiology, University of Pennsylvania, Philadelphia, PA 19014 (United States)

2011-05-15

Introduction: Nitroimidazole (azomycin) derivatives labeled with radioisotopes have been developed as cancer imaging and radiotherapeutic agents based on the oncological hypoxic mechanism. By attaching nitroimidazole core with different functional groups, we synthesized new nitroimidazole derivatives and evaluated their potentiality as tumor imaging agents. Methods: Starting with commercially available 2-nitroimidazole, 2-fluoro-N-(2-(2-nitro-1H-imidazol-1-yl)ethyl)acetamide (NEFA, [{sup 19}F]7) and 2-(2-methyl-5-nitro-1H-imidazol-1-yl)ethyl 2-fluoroacetate (NEFT, [{sup 19}F]8), as well as radiolabeling precursors, the bromo-substituted analogs were quickly synthesized through a three-step synthetic pathway. The precursors were radiolabeled with [{sup 18}F]F{sup -}/18-crown-6/KHCO{sub 3} in dimethyl sulfoxide at 90{sup o}C for 10 min followed by purification with an Oasis HLB cartridge. Biodistribution studies were carried out in EMT-6 tumor-bearing mice. The uptake (%ID/g) in tumors and normal tissues were measured at 30 min postinjection. Liquid chromatography-electrospray ionization mass spectrometry (LC/MS) was used to distinguish metabolites from parent drugs in urine and plasma of rat injected with 'cold' NEFA ([{sup 19}F]7) and NEFT ([{sup 19}F]8). Results: Two radiotracers, [{sup 18}F]NEFA ([{sup 18}F]7) and [{sup 18}F]NEFT ([{sup 18}F]8), were prepared with average yields of 6%-7% and 9%-10% (not decay corrected). Radiochemical purity for both tracers was >95% as determined by HPLC. Biodistribution studies in EMT-6 tumor-bearing mice indicated that the tumor to blood and tumor to liver ratios of both [{sup 18}F]7 (0.96, 0.61) and [{sup 18}F]8 (0.98, 1.10) at 30 min were higher than those observed for [{sup 18}F]FMISO (1) (0.91, 0.59), a well-investigated azomycin-type hypoxia radiotracer. Liquid chromatography-electrospray ionization mass spectrometry analysis demonstrated that fluoroacetate was the main in vivo metabolite for both NEFA ([{sup 19

Algorithms for Computing the Magnetic Field, Vector Potential, and Field Derivatives for a Thin Solenoid with Uniform Current Density

Energy Technology Data Exchange (ETDEWEB)

Walstrom, Peter Lowell [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-08-07

A numerical algorithm for computing the field components B_r and B_z and their r and z derivatives with open boundaries in cylindrical coordinates for radially thin solenoids with uniform current density is described in this note. An algorithm for computing the vector potential A_θ is also described. For the convenience of the reader, derivations of the final expressions from their defining integrals are given in detail, since their derivations are not all easily found in textbooks. Numerical calculations are based on evaluation of complete elliptic integrals using the Bulirsch algorithm cel. The (apparently) new feature of the algorithms described in this note applies to cases where the field point is outside of the bore of the solenoid and the field-point radius approaches the solenoid radius. Since the elliptic integrals of the third kind normally used in computing B_z and A_θ become infinite in this region of parameter space, fields for points with the axial coordinate z outside of the ends of the solenoid and near the solenoid radius are treated by use of elliptic integrals of the third kind of modified argument, derived by use of an addition theorem. Also, the algorithms also avoid the numerical difficulties the textbook solutions have for points near the axis arising from explicit factors of 1/r or 1/r² in the some of the expressions.

Structure and evaluation of antibacterial and antitubercular properties of new basic and heterocyclic 3-formylrifamycin SV derivatives obtained via 'click chemistry' approach.

Science.gov (United States)

Pyta, Krystian; Klich, Katarzyna; Domagalska, Joanna; Przybylski, Piotr

2014-09-12

Thirty four novel derivatives of 3-formylrifamycin SV were synthesized via reductive alkylation and copper(I)-catalysed azide-alkyne cycloaddition. According to the obtained results, 'click chemistry' can be successfully applied for modification of structurally complex antibiotics such as rifamycins, with the formation of desired 1,2,3-triazole products. However, when azide-alkyne cycloaddition on 3-formylrifamycin SV derivatives demanded higher amount of catalyst, lower temperature and longer reaction time because of the high volatility of substrates, an unexpected intramolecular condensation with the formation of 3,4-dihydrobenzo[g]quinazoline heterocyclic system took place. Structures of new derivatives in solution were determined using one- and two-dimensional NMR methods and FT-IR spectroscopy. Computational DFT and PM6 methods were employed to correlate their conformation and acid-base properties to biological activity and establish SAR of the novel compounds. Microbiological, physico-chemical (logP, solubility) and structural studies of newly synthesised rifamycins indicated that for the presence of relatively high antibacterial (MIC ~0.01 nmol/mL) and antitubercular (MIC ~0.006 nmol/mL) activities, a rigid and basic substituent at C(3) arm, containing a protonated nitrogen atom "open" toward intermolecular interactions, is required. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Interpretation of field potentials measured on a multi electrode array in pharmacological toxicity screening on primary and human pluripotent stem cell-derived cardiomyocytes

NARCIS (Netherlands)

Tertoolen, L.G.J.; Braam, S. R.; van Meer, B.J.; Passier, R.; Mummery, C. L.

2018-01-01

Multi electrode arrays (MEAs) are increasingly used to detect external field potentials in electrically active cells. Recently, in combination with cardiomyocytes derived from human (induced) pluripotent stem cells they have started to become a preferred tool to examine newly developed drugs for

In vivo hepatic differentiation potential of human umbilical cord-derived mesenchymal stem cells: Therapeutic effect on liver fibrosis/cirrhosis

OpenAIRE

Zhang, Guo-Zun; Sun, Hui-Cong; Zheng, Li-Bo; Guo, Jin-Bo; Zhang, Xiao-Lan

2017-01-01

AIM To investigate the hepatic differentiation potential of human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) and to evaluate their therapeutic effect on liver fibrosis/cirrhosis. METHODS A CCl4-induced liver fibrotic/cirrhotic rat model was used to assess the effect of hUC-MSCs. Histopathology was assessed by hematoxylin and eosin (H&E), Masson trichrome and Sirius red staining. The liver biochemical profile was measured using a Beckman Coulter analyzer. Expression analysis was ...

Modeling the effect of intermolecular force on the size-dependent pull-in behavior of beam-type NEMS using modified couple stress theory

Energy Technology Data Exchange (ETDEWEB)

Beni, Yaghoub Tadi; Karimipour, Iman [Shahrekord University, Shahrekord (Iran, Islamic Republic of); Abadyan, Mohamadreza [Islamic Azad University, Shahrekord (Iran, Islamic Republic of)

2014-09-15

Experimental observations reveal that the physical response of nano structures is size-dependent. Herein, modified couple stress theory has been used to study the effect of intermolecular van der Waals force on the size dependent pull-in of nano bridges and nano cantilevers. Three approaches including using differential transformation method, applying numerical method and developing a simple lumped parameter model have been employed to solve the governing equation of the systems. The pull-in parameters i.e. critical tip deflection and instability voltage of the nano structures have been determined. Effect of the van der Waals attraction and the size dependency and the importance of coupling between them on the pull-in performance have been discussed.

Modeling the effect of intermolecular force on the size-dependent pull-in behavior of beam-type NEMS using modified couple stress theory

International Nuclear Information System (INIS)

Beni, Yaghoub Tadi; Karimipour, Iman; Abadyan, Mohamadreza

2014-01-01

Experimental observations reveal that the physical response of nano structures is size-dependent. Herein, modified couple stress theory has been used to study the effect of intermolecular van der Waals force on the size dependent pull-in of nano bridges and nano cantilevers. Three approaches including using differential transformation method, applying numerical method and developing a simple lumped parameter model have been employed to solve the governing equation of the systems. The pull-in parameters i.e. critical tip deflection and instability voltage of the nano structures have been determined. Effect of the van der Waals attraction and the size dependency and the importance of coupling between them on the pull-in performance have been discussed.

Attention effects at auditory periphery derived from human scalp potentials: displacement measure of potentials.

Science.gov (United States)

Ikeda, Kazunari; Hayashi, Akiko; Sekiguchi, Takahiro; Era, Shukichi

2006-10-01

It is known in humans that electrophysiological measures such as the auditory brainstem response (ABR) are difficult to identify the attention effect at the auditory periphery, whereas the centrifugal effect has been detected by measuring otoacoustic emissions. This research developed a measure responsive to the shift of human scalp potentials within a brief post-stimulus period (13 ms), that is, displacement percentage, and applied it to an experiment to retrieve the peripheral attention effect. In the present experimental paradigm, tone pips were exposed to the left ear whereas the other ear was masked by white noise. Twelve participants each conducted two conditions of either ignoring or attending to the tone pips. Relative to averaged scalp potentials in the ignoring condition, the shift of the potentials was found within early component range during the attentive condition, and displacement percentage then revealed a significant magnitude difference between the two conditions. These results suggest that, using a measure representing the potential shift itself, the peripheral effect of attention can be detected from human scalp potentials.

Synthesis, properties and applications of biodegradable polymers derived from diols and dicarboxylic acids: from polyesters to poly(ester amide)s.

Science.gov (United States)

Díaz, Angélica; Katsarava, Ramaz; Puiggalí, Jordi

2014-04-25

Poly(alkylene dicarboxylate)s constitute a family of biodegradable polymers with increasing interest for both commodity and speciality applications. Most of these polymers can be prepared from biobased diols and dicarboxylic acids such as 1,4-butanediol, succinic acid and carbohydrates. This review provides a current status report concerning synthesis, biodegradation and applications of a series of polymers that cover a wide range of properties, namely, materials from elastomeric to rigid characteristics that are suitable for applications such as hydrogels, soft tissue engineering, drug delivery systems and liquid crystals. Finally, the incorporation of aromatic units and α-amino acids is considered since stiffness of molecular chains and intermolecular interactions can be drastically changed. In fact, poly(ester amide)s derived from naturally occurring amino acids offer great possibilities as biodegradable materials for biomedical applications which are also extensively discussed.

Synthesis and In Vitro Evaluation of New Thiosemicarbazone Derivatives as Potential Antimicrobial Agents

Directory of Open Access Journals (Sweden)

Zafer Asım Kaplancıklı

2016-01-01

Full Text Available In an effort to develop potent antimicrobial agents, new thiosemicarbazone derivatives were synthesized via the reaction of 4-[4-(trifluoromethylphenyl]thiosemicarbazide with aromatic aldehydes. The compounds were evaluated for their inhibitory effects on pathogenic bacteria and yeasts using the CLSI broth microdilution method. Microplate Alamar Blue Assay was also carried out to determine the antimycobacterial activities of the compounds against Mycobacterium tuberculosis H37Rv. Among these derivatives, compounds 5 and 11 were more effective against Enterococcus faecalis (ATCC 29212 than chloramphenicol, whereas compounds 1, 2, and 12 and chloramphenicol showed the same level of antibacterial activity against E. faecalis. Moreover, compound 2 and chloramphenicol exhibited the same level of antibacterial activity against Staphylococcus aureus. On the other hand, the most potent anticandidal derivatives were found as compounds 2 and 5. These derivatives and ketoconazole exhibited the same level of antifungal activity against Candida glabrata. According to the Microplate Alamar Blue Assay, the tested compounds showed weak to moderate antitubercular activity.

Establishing clonal cell lines with endothelial-like potential from CD9(hi, SSEA-1(- cells in embryonic stem cell-derived embryoid bodies.

Directory of Open Access Journals (Sweden)

Qizhou Lian

Full Text Available BACKGROUND: Differentiation of embryonic stem cells (ESCs into specific cell types with minimal risk of teratoma formation could be efficiently directed by first reducing the differentiation potential of ESCs through the generation of clonal, self-renewing lineage-restricted stem cell lines. Efforts to isolate these stem cells are, however, mired in an impasse where the lack of purified lineage-restricted stem cells has hindered the identification of defining markers for these rare stem cells and, in turn, their isolation. METHODOLOGY/PRINCIPAL FINDINGS: We describe here a method for the isolation of clonal lineage-restricted cell lines with endothelial potential from ESCs through a combination of empirical and rational evidence-based methods. Using an empirical protocol that we have previously developed to generate embryo-derived RoSH lines with endothelial potential, we first generated E-RoSH lines from mouse ESC-derived embryoid bodies (EBs. Despite originating from different mouse strains, RoSH and E- RoSH lines have similar gene expression profiles (r(2 = 0.93 while that between E-RoSH and ESCs was 0.83. In silico gene expression analysis predicted that like RoSH cells, E-RoSH cells have an increased propensity to differentiate into vasculature. Unlike their parental ESCs, E-RoSH cells did not form teratomas and differentiate efficiently into endothelial-like cells in vivo and in vitro. Gene expression and FACS analysis revealed that RoSH and E-RoSH cells are CD9(hi, SSEA-1(- while ESCs are CD9(lo, SSEA-1(+. Isolation of CD9(hi, SSEA-1(- cells that constituted 1%-10% of EB-derived cultures generated an E-RoSH-like culture with an identical E-RoSH-like gene expression profile (r(2 = 0.95 and a propensity to differentiate into endothelial-like cells. CONCLUSIONS: By combining empirical and rational evidence-based methods, we identified definitive selectable surface antigens for the isolation and propagation of lineage-restricted stem cells

Derivative expansions of renormaliztion group effective potentials for φ4 field theories

International Nuclear Information System (INIS)

Shepard, J.R.; McNeil, J.A.

1995-01-01

We approximate an exact Renormalization Group (RG) equation for the flow of the effective action of φ 4 field theories by including next-to-leading order (NLO) terms in a derivative expansion. This level of approximation allows us to treat effects of wavefunction renormalization which are beyond the scope of the leading order (LO) formulation. We compare calculations based on a open-quote latticized close quotes version of our RG equation in 3 Euclidean dimensions directly with Monte Carlo (MC) results and find excellent overall agreement as well as substantial improvement over LO calculations. We solve the continuum form of our equation to find the Wilson fixed point and determine the critical exponent η (0.046). We also find the critical exponents ν (0.666) and ω (0.735). These latter two are in much improved agreement with open-quote world's bestclose quotes values com- pared to those obtained at LO (where no prediction for η is possible). We also find that the open-quote universal potential close-quote determined via MC methods by Tsypin can be understood quantitatively using our NLO RG equations. Careful analysis shows that ambiguities which plague open-quote smooth cutoffclose quotes formulations do not arise with our RG equations

Accumulation and potential dissolution of Chernobyl-derived radionuclides in river bottom sediment

International Nuclear Information System (INIS)

Sanada, Yukihisa; Matsunaga, Takeshi; Yanase, Nobuyuki; Nagao, Seiya; Amano, Hikaru; Takada, Hideshige; Tkachenko, Yuri

2002-01-01

Areas contaminated with radionuclides from the Chernobyl nuclear accident have been identified in Pripyat River near the Chernobyl Nuclear Power Plant. The river bottom sediment cores contained 137 Cs (10 5 - 10 6 Bq/m 2 ) within 0-30 cm depth, whose concentration is comparable to that in the ground soil in the vicinity of the nuclear power plant (the Exclusion Zone). The sediment cores also accumulated 90 Sr (10 5 Bq/m 2 ), 239,240 Pu (10 4 Bq/m 2 ) and 241 Am (10 4 Bq/m 2 ) derived from the accident. Several nuclear fuel particles have been preserved at 20-25 cm depth that is the peak area of the concentrations of the radionuclides. Th ese inventories in the bottom sediments were compared with those of the released radionuclides during the accident. An analysis using a selective sequential extraction technique was applied for the radionuclides in the sediments. Results suggest that the possibility of release of 137 Cs and 239,240 Pu from the bottom sediment was low compared with 90 Sr. The potential dissolution and subsequent transport of 90 Sr from the river bottom sediment should be taken into account with respect to the long-term radiological influence on the aquatic environment

Alchemical derivatives of reaction energetics

Science.gov (United States)

Sheppard, Daniel; Henkelman, Graeme; von Lilienfeld, O. Anatole

2010-08-01

Based on molecular grand canonical ensemble density functional theory, we present a theoretical description of how reaction barriers and enthalpies change as atoms in the system are subjected to alchemical transformations, from one element into another. The change in the energy barrier for the umbrella inversion of ammonia is calculated along an alchemical path in which the molecule is transformed into water, and the change in the enthalpy of protonation for methane is calculated as the molecule is transformed into a neon atom via ammonia, water, and hydrogen fluoride. Alchemical derivatives are calculated analytically from the electrostatic potential in the unperturbed system, and compared to numerical derivatives calculated with finite difference interpolation of the pseudopotentials for the atoms being transformed. Good agreement is found between the analytical and numerical derivatives. Alchemical derivatives are also shown to be predictive for integer changes in atomic numbers for oxygen binding to a 79 atom palladium nanoparticle, illustrating their potential use in gradient-based optimization algorithms for the rational design of catalysts.

Intermolecular crosslinks mediate aggregation of phospholipid vesicles by pulmonary surfactant-associated protein SAP-35

International Nuclear Information System (INIS)