bluuebunny/crossref_metadata_2025_split huggingface dataset:
Additivity Rule of the Partial Molal Volume. 4. Its Proof Based on the Postulate of Independent Volume Changes for Unit Reactions
Authors: Yoshimura Y. , Nakahara M. 
Published: July 2012

AbstractThe additivity rule of the partial molal volume is proved to be equivalent to the postulate of independent volume changes for unit reactions which states that the (configurational) volume changes are determined by the reaction sites and not affected by the other sites in the composite molecule. The postulate of independent volume change leads to the reduction of the multiple body distribution function to the product of the pair distribution functions between the nearest‐neighbor sites in the composite molecule. The postulate is applied to the model system of n‐alkane solution composed of hard spheres. The calculated result based on a proper pair cavity distribution function well reproduces the characteristics of the additivity rule of the partial molal volume of n‐alkanes, and predicts molecular dimensions of n‐alkane in a reasonable manner.
Deuterium Isotope Effect in the Photophysics of Chromium (III) Alkylamine Complexes
Authors: Ditze Alexander , Wasgestian F. 
Published: July 2012

AbstractThe photophysical properties of a series of chromium alkylamines with CrN6 skeletons were studied in a mixture of dimethylsulfoxide (DMSO) and water (1:1 vv). For the analogous N‐deuterated compounds DMSO/D2O (1:1 vv) was used as the solvent Absorption spectra, phosphorescence quantum yields, and phosphorescence decay times were measured. At low temperatures the protonated complexes were found to decay mainly nonradiatively with NH stretching modes accepting the excitation energy. In the deuterated species the radiative decay became important. Phosphorescence quantum yields as high as 0.42 were obtained. ND stretching modes did not significantly contribute to the nonradiative deactivation in agreement with Kupka's theory. At higher temperatures (250–295 K) a smaller isotope effect was observed. The apparent activation energies of the high temperature decay increased on deuteration.
Periodic Precipitation During Internal Oxidation of Iron‐Doped Magnesium Oxide Crystals
Authors: Ricoult D. L. , Schmalzried H. 
Published: July 2012

Abstract(Mg,Fe)O single‐crystals have been oxidized in air, at temperatures ranging from 700 to 1150°C. The oxidation occurs internally and yields spinel precipitates (MgFe2O4) dispersed in a matrix of almost pure MgO. In several samples annealed at 900°C, periodical precipitation could be observed. This first observation in a ceramic material of a phenomenon long reported in colloidal systems is discussed in terms of point defect transport properties.
Excess Properties of Liquid Cyclohexane/Hydrocarbon Mixtures III. Application of an Extended Prigogine‐Flory‐Patterson‐Theory
Authors: Wagner H. , Heintz A. , Lichtenthaler R. N. 
Published: July 2012

AbstractExperimental results ofHEandGEfor mixtures of cyclohexane with saturated and unsaturated alkanes are interpreted by an extended version of thePrigogine‐FIory‐Patterson‐Theory (PFP‐theory) which accounts for the effect of theCorrelation ofMolecularOrder (CMO) observed for longer n‐alkanes in the liquid state. Theoretically based expressions of the enthalpic and the entropic contribution to the CMO are presented and tested. The results show that the theoretical predictions are in principal correct, i. e. all the approximations made are reasonable. In case of mixtures containing unsaturated hydrocarbons a qualitätive and sometimes even quantitative description of the excess properties within the framework of the PFP‐theory is possible.
Interfaces in Solid‐State Reactions
Authors: Carter C. B. 
Published: July 2012

AbstractIllustrations of the structure of phase boundaries involved in solid‐state reactions in ceramic oxides and of the formation of grain boundaries by the movement of phase boundaries are presented. Examples of experimental studies have been chosen to emphasise how both the cations and anions can influence the structure of the phase boundaries and the manner in which the reaction proceeds. In the oxide systems discussed here, the phase boundaries tend to facet parallel to certain planes even in the case where the anion sublattice is effectively undisturbed. This observation emphasises that, although the anion sublattice often determines the interface structure, the influence of the cations on the selection of the boundary plane cannot be neglected. The discussion is focused here on the growth of spinel in three different oxide matrices, namely in a wustite phase (NiO), a rhombohedral sesquioxide (Al2O3) and an olivine ((FeMg)2SiO4).
Structure and Thermodynamics of H‐Insertion in Mo(W)‐Oxides
Authors: Hibble S. J. , Dickens P. G. 
Published: July 2012

AbstractHydrogen insertion compounds HxMOn are formed from many transition oxides by the reaction of dissociated hydrogen at ambient temperature. Well known examples are provided by WO3 (ReO3 like structure) and MoO3 (layer structure).—In the present work hydrogen insertion compounds formed by the simple and mixed oxides in the (Mo, W)O3 system are discussed. Structural information has been obtained for a number of compounds using elastic and inelastic neutron scattering and the bonding of the inserted hydrogen is discussed. Thermochemical measurements have been made and the enthalpies of hydrogen insertion into the oxides determined; these are compared with the Gibbs free energies determined from electrochemical measurements.
Exsolution and Phase Transformations in Synthetic Pyroxenes X‐Ray and TEM‐Studies at Elevated Temperatures
Authors: Fuess H. , Schröpfer L. , Feuer H. 
Published: July 2012

AbstractMany important pyroxene minerals undergo subsolidus reactions during their formation process between ∼ 700°C and ∼ 1200°C. The nature of these reactions depends on chemical composition, temperature and pressure. As a reaction result various microtextures may be observed by transmission electron microscopy. These include stacking sequence faults, twinning and antiphase domains which may be related to structural phase transitions.—Exsolution in clinopyroxenes produces lamellae of Ca‐rich (augite) and Ca‐poor (pigeonite) pyroxenes parallel to (100) and (001). The exsolution may result from fluctuations in chemical composition (spinodal decomposition) or from nucleation and growth. The appearance of the final lamellae does not reflect the original process.—Direct in‐situ heating experiments give some indication for the subsolidus reactions. By precession photographs a simultaneous occurrence of lamellae parallel to (001) and (100) is observed. Attempts are made to classify the observations, determine a time‐temperature‐transformation (TTT)‐diagram, and to correlate the observed microstructure with the thermal history of the mineral. The experiments described were carried out on synthetic samples with known cooling rates.
An Equation of State for Binary Fluid Mixtures to High Temperatures and High Pressures
Authors: Christoforakos M. , Franck E. U. 
Published: July 2012

AbstractAn equation of state has been constructed which can describe and predict phase equilibria and critical curves of fluid binary systems. The equation is particularly suitable for regions of elevated temperatures and pressures and for systems with molecules of high polarity, for example for aqueous systems. The computer simulation based Carnahan‐Starling term with temperature dependent particle diameter describes the repulsion. The attraction term uses a square well potential. The values of the parameters in the equation are derived from critical data of the pure mixture partners or have a defined relation to the chosen model of molecular interaction. Thus predictions are possible. The experimental critical curve of the H2O‐N2system to 250 MPa could be well represented with two adjusted parameters. With the same set of adjusted parameter values critical curves of the systems H2O‐CH4and H2O‐Xe have been calculated to 220 MPa. Critical curve and the binodal (phase‐equilibrium) surface in the pressure‐temperature‐composition diagram could be calculated for H2O‐CO2above about 500 K to 200 MPa with a different pair of mixture parameters. A comparison with other equations is made. The possibility to predict excess molar volumes of supercritical dense H2O‐CH4‐mixtures to 400°C and 150 MPa is demonstrated.
Electronegativities and Hardnesses of the Main Group Elements from Density Functional Theory: Dependence on the Hybridization of the Chemical Bond
Authors: Böhm Michael C. , Schmidt Peter C. 
Published: July 2012

AbstractAtomic electronegativities χa are calculated for all main group elements (besides the rare gas atoms) as a function of both the partial atomic charge q and the hybridization (relative s and p character) of the valence orbital srp1‐r·χa(q,r) is calculated by studying the total atomic energy Ea as a function of q and r using the Iczkowski and Margrave definition for χa. Within a good approximation it is found that χa can be fitted by a polynominal χa(q,r) = A0 + B0r)+(A1+B1r)q + (A2 + B2r)q2. The Ai and Bi are given for all atoms considered here. From the principle of equalization of electronegativity partial charges and group electronegativities are calculated. The results are compared with data available from the literature.
Helical Twisting Power of Induced Twisted Smectic C* Phases
Authors: Stegemeyer H. , Kersting H.‐J. , Kuczynski W. 
Published: July 2012

AbstractThe helically structured cholesteric and smectic C* phases have been induced by chiral guest molecules in liquid crystalline host systems exhibiting nematic as well as Scphases. The helical twisting power δ has been measured for those systems: i) In all cases values of δchol> δc*were obtained; ii) in the induced Sc* but not in the cholesteric phases there exists a threshold mole fraction x0Gof the chiral guest molecules below which no helical twist will be induced.—These experimental results are discussed in terms of the layer structure of the Scphase. By means of a simple structure model of the induces S*cphase the occurance of a threshold guest concentration can be understood. A relation between the ratio δchol/δc*and x0Ghas been derived from the model in good agreement with the experimental data.
1H NMR studies of the system Ti3SbHx
Authors: Rajalakshmi Natarajan , Rama Rao K. V. S. , Weiss Alarich 
Published: July 2012

AbstractProton magnetic resonance measurements were carried out on hydrogenated samples Ti3SbHx, at different hydrogen concentrations in the range 0.3 ≤x≤ 1.74. From a comparison of the experimental second moment of the1H NMR line with the calculated one it was inferred that hydrogen occupies the tetrahedral interstitial sites surrounded by Ti atoms in the Ti3Sb lattice. The influence of temperature in the range 100 ≤T/K≤ 300 on the1H NMR in some of the hydrides showed the occurrence of motional narrowing from which the correlation frequency (vc), activation energy (Ea) and diffusion coefficient (D) were evaluated as 104Hz, 0.10 eV, and 10−12cm2/s, respectively. It was found that the hydrogen diffusion is easier in the Ti3Sb lattice compared to other Ti based alloys.
Electrochemical on line mass spectrometry on a rotating electrode inlet system
Authors: Tegtmeyer D. , Heitbaum J. , Heindrichs A. 
Published: July 2012

AbstractA rotating inlet system was constructed in order to combine the rotating disc technique with on line mass spectrometry. The quantitative correlation between the Faradaic current by which a species is formed and the ion current at the detector of the mass spectrometer is used to calculate collection efficiencies on two different types of electrodes and for different types of reactions. On the basis of these results transport to and from and inside the porous catalyst layer is discussed.
Scattering of Light, X‐rays and Neutrons in Solutions of Biological Macromolecules
Authors: Eisenberg Henryk 
Published: July 2012

AbstractIt is shown that the forward scattering of light, X‐rays and neutrons conceptually relates to osmotic pressure and ultracentrifugation, allowing the correct determination of molecular masses, hydration and solvent interactions in multicomponent and polyelectrolyte systems. Combination of neutron scattering length and mass density increments in contrast variation experiments is shown to be particularly useful for the calculation of interaction parameters and partial specific volumes. Whereas static size, shape and other parameters may be derived from the angular dependence of the intensities of scattering, quasi‐elastic laser light scattering yields dynamic information about motion and internal dynamics of biological macromolecules. —Application to nucleic acids and to proteins from extremely halophilic enzymes is briefly indicated.
Ionic Dynamics in [(CH3)4N]SbF6 Crystals as Studied by the Temperature Dependence of 1H and 19F NMR Spin‐Lattice Relaxation Times
Authors: Sato Setsuko , Kondo Miyuki , Nakamura Daiyu , Ikeda Ryuichi 
Published: July 2012

AbstractThe temperature dependence studies of 1H and 19F NMR spin‐lattice relaxation times (T1) as well as differential thermal analysis measurements were carried out for [(CH3)4N]SbF6 crystals. A phase transition assignable to the second order one was located at 200 K, above which temperature the temperature gradient of 1H T1 and 19F T1 curves became slightly gentler. The appearance of the 1H T1 curve was BPP like one although a maximum was detected at ca. 110 K. The 1H T1 minimum was explained as resulting from the CH3 C3 reorientation and the overall reorientation of the cation activated at almost the same temperature. The 19F T1 curves observed at 19.5 and 32 MHz were somewhat complicated. On the high temperature region above ca. 120 K, 19F T1 was determined mainly by the motion of the cation activated at higher temperatures than that of the anion through 1H‐19F magnetic dipolar interactions. On the other hand, 19F T1 observed below 120 K have a broad minimum attributable to the overall reorientation of the complex anion. The motional parameters for the above motions were derived. On the analysis of the T1 curves observed, cross relaxation mechanism operative between 1H and 19F nuclei is fully considered.
Effects of aripiprazole and its active metabolite dehydroaripiprazole on the activities of drug efflux transporters expressed both in the intestine and at the blood–brain barrier
Authors: Nagasaka Yasuhisa , Oda Kazuo , Iwatsubo Takafumi , Kawamura Akio , Usui Takashi 
Published: July 2012

ABSTRACTThe inhibition potencies of aripiprazole and its active metabolite, dehydroaripiprazole, on the activities of human multidrug resistance protein 1 (MDR1/ABCB1; P‐glycoprotein), breast cancer resistance protein (BCRP/ABCG2) and multidrug resistance‐associated protein 4 (MRP4/ABCC4), that are drug efflux transporters expressed both in the intestine and at the blood–brain barrier (BBB), were investigated. Aripiprazole and dehydroapripiprazole showed relatively strong inhibitory effects on human MDR1 with IC50 values of 1.2 and 1.3 µm in human MDR1‐transfected Mardin‐Darby canine kidney (MDCKII‐MDR1) cells, respectively. The inhibition potencies of other atypical antipsychotics (risperidone, paliperidone, olanzapine and ziprasidone) for human MDR1 were also evaluated using the same in vitro experimental system and IC50 values were more than 10‐fold higher than those of the two compounds. Aripiprazole and dehydroaripiprazole also had inhibition potencies against human BCRP with IC50 values of 3.5 and 0.52 µm, respectively. The ratios of steady‐state unbound concentrations of aripiprazole and dehydroaripiprazole to their IC50 values against human MDR1 and BCRP activities were less than 0.1, whereas the theoretically maximum gastrointestinal concentration of aripiprazole ([I]2) to its IC50 values was much higher than the cut‐off value of 10, proposed by the International Transporter Consortium (ITC) and the Food and Drug Administration (FDA). In contrast, aripiprazole and dehydroaripiprazole showed almost no inhibitory effect against the activity of human MRP4. These findings indicate that aripiprazole is unlikely to cause drug–drug interactions (DDIs) at the BBB when co‐administered with substrate drugs of these drug transporters investigated. However, interactions at the intestinal absorption process may be of concern. Copyright © 2012 John Wiley & Sons, Ltd.
Effect of pH, mucin and bovine serum on rifampicin permeability through Caco‐2 cells
Authors: Gonçalves José Eduardo , Ballerini Fernandes Mariane , Chiann Chang , Gai Maria Nella , De Souza Jacqueline , Storpirtis Sílvia 
Published: July 2012

ABSTRACTRifampicin, a poorly soluble drug, has great importance in therapeutics as it is the main drug used to treat tuberculosis. The characterization of its permeability and the factors that influence it represent an important tool for predicting its bioavailability. Caco‐2 cell monolayers were used as models of the intestinal mucosa to assess the uptake and transport of rifampicin and the effects of various experimental conditions were investigated, in order to establish the influence of these variables on rifampicin permeability. Different pHs (5.8, 6.8 and 7.4) in the apical medium, the presence or absence of mucin (3.0% w/v) in the donor site and the presence or absence of bovine serum albumin (4.0% v/v) in the receptor chamber were the evaluated conditions. The quantification of rifampicin in the apical or basolateral chambers was performed by a validated HPLC‐UV method. The change in the donor chamber pH showed that permeability values were greater at pH 6.8, although this increase does not result in an alteration of the qualitative classification of rifampicin, which has high permeability. Mucin and bovine serum showed no effects on the permeability of rifampicin at the concentration tested. Overall, the current study suggests that pH, artificial mucin and bovine serum proteins have no influence on rifampicin permeability. Copyright © 2012 John Wiley & Sons, Ltd.
Mechanistic analysis of solute transport in an in vitro physiological two‐phase dissolution apparatus
Authors: Mudie Deanna M. , Shi Yi , Ping Haili , Gao Ping , Amidon Gordon L. , Amidon Gregory E. 
Published: July 2012

ABSTRACTIn vitro dissolution methodologies that adequately capture the oral bioperformance of solid dosage forms are critical tools needed to aid formulation development. Such methodologies must encompass important physiological parameters and be designed with drug properties in mind. Two‐phase dissolution apparatuses, which contain an aqueous phase in which the drug dissolves (representing the dissolution/solubility component) and an organic phase into which the drug partitions (representing the absorption component), have the potential to provide meaningful predictions of in vivo oral bioperformance for some BCS II, and possibly some BCS IV drug products. Before such an apparatus can be evaluated properly, it is important to understand the kinetics of drug substance partitioning from the aqueous to the organic medium. A mass transport analysis was performed of the kinetics of partitioning of drug substance solutions from the aqueous to the organic phase of a two‐phase dissolution apparatus. Major assumptions include pseudo‐steady‐state conditions, a dilute aqueous solution and diffusion‐controlled transport. Input parameters can be measured or estimated a priori. This paper presents the theory and derivation of our analysis, compares it with a recent kinetic approach, and demonstrates its effectiveness in predicting in vitro partitioning profiles of three BCS II weak acids in four different in vitro two‐phase dissolution apparatuses. Very importantly, the paper discusses how a two‐phase apparatus can be scaled to reflect in vivo absorption kinetics and for which drug substances the two‐phase dissolution systems may be appropriate tools for measuring oral bioperformance. Copyright © 2012 John Wiley & Sons, Ltd.
The effect of context‐specific versus nonspecific subconscious goals on employee performance
Authors: Latham Gary P. , Piccolo Ronald F. 
Published: July 2012

AbstractWe investigated the effect of context‐specific versus general subconscious goals on job performance in a call center. Employees (n = 54) were randomly assigned to a condition where they were primed by (a) a photograph of people making telephone calls in a call center, (b) a woman winning a race, or (c) a control group. Job performance was measured by the (1) number of and (2) monetary value of pledges from donors. None of the participants in the two experimental conditions showed conscious awareness of a prime. Analysis of variance indicated that both a subconscious context‐specific and a subconscious general goal aroused the implicit need for achievement as assessed by a projective measure, the Thematic Apperception Test (TAT). Both types of primed goals led to a significant increase in the number of pledges during a four‐day workweek. Consistent with goal‐setting theory, employees in the context‐specific condition raised more money than those in the general achievement (one‐tailed t‐test) and control (two‐tailed t‐test) conditions. © 2012 Wiley Periodicals, Inc.
Blockade of JNK and NFAT pathways attenuates orthopedic particle‐stimulated osteoclastogenesis of human osteoclast precursors and murine calvarial osteolysis
Authors: Yamanaka Yasuhiro , Clohisy John C.F. , Ito Hiroshi , Matsuno Takeo , Abu‐Amer Yousef 
Published: July 2012

AbstractParticles released from orthopedic implants attract immune host defense cells to the bone‐implant interface and contribute to development of inflammation. The inflammatory microenvironment supports recruitment and differentiation of osteoclasts, the primary culprit of osteolysis. Therefore, understanding the complex signals that contribute to osteoclastogenesis and osteolysis is a sensible approach to design strategies to inhibit bone loss. The signaling cascades that coordinate osteoclastogenesis have been widely investigated. These include MAP kinases, Akt/PI3K pathway, NF‐κB signal transduction pathway, and NFAT pathway. We have recently reported that polymethylmethacrylate (PMMA) particles activate the NFAT pathway in murine osteoclast precursors and that NFAT inhibitors dose‐dependently block PMMA‐induced osteoclastogenesis. In the current study, we examined the role of JNK and NFATc1 in mice in response to PMMA particles using murine calvaria model. We show that locally administered MAPK/JNK inhibitor SP600125 and calcineurin/NFAT inhibitor cyclosporine‐A effectively blocked PMMA‐induced osteolysis in murine calvaria. To buttress the clinical relevance of JNK/NFATc1‐based regulation of PMMA‐induced osteoclastogenesis, we evaluated the effect of PMMA using human macrophages. We demonstrate that SP600125 and cyclosporine‐A abolished particle‐induced osteoclastogenesis in human osteoclast progenitors retrieved from patients undergoing total hip replacement. Thus JNK and NFATc1 appear to act as significant mediators of orthopedic particle‐induced osteolysis in humans. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:67–72, 2012