bluuebunny/crossref_metadata_2025 huggingface dataset:
Starch‐entrapped microspheres extend in vitro fecal fermentation, increase butyrate production, and influence microbiota pattern
Authors: Rose Devin J. , Keshavarzian Ali , Patterson John A. , Venkatachalam Mahesh , Gillevet Patrick , Hamaker Bruce R.
Published: October 2008

Previous research has revealed that waxy corn starch which has been entrapped in a matrix of electrostatically cross‐linked alginate, shows a slow digestion rate such that much of the starch may reach the colon; thus making this a new type of resistant starch. The purpose of this research was to test the fermentative properties of starch‐entrapped microspheres using a batch fecal fermentation method. Fermentation of starch‐entrapped microspheres showed significantly lower rates of gas production compared to waxy corn starch, and showed significant increases in total SCFAs during the latter stages of fermentation (24–48 h), whereas waxy corn starch did not. Cooking the starch‐entrapped microspheres increased the amount of SCFAs and the molar fraction of butyrate produced during fermentation. Bacterial fingerprinting revealed that uncooked starch‐entrapped microspheres have a unique effect on the microbiota that is different from waxy corn starch alone, but cooking causes a shift toward a pattern more closely resembling that of the starch. Starch‐entrapped microspheres may deliver slowly fermentable carbohydrate to the colon, with the ability to influence the microbiota. Further human studies are required to determine whether these characteristics occur in vivo.
Meshfree simulation of failure modes in thin cylinders subjected to combined loads of internal pressure and localized heat
Authors: Qian Dong , Eason Thomas , Li Shaofan , Liu Wing Kam
Published: October 2008

This paper focuses on the non‐linear responses in thin cylindrical structures subjected to combined mechanical and thermal loads. The coupling effects of mechanical deformation and temperature in the material are considered through the development of a thermo‐elasto‐viscoplastic constitutive model at finite strain. A meshfree Galerkin approach is used to discretize the weak forms of the energy and momentum equations. Due to the different time scales involved in thermal conduction and failure development, an explicit–implicit time integration scheme is developed to link the time scale differences between the two key mechanisms. We apply the developed approach to the analysis of the failure of cylindrical shell subjected to both heat sources and internal pressure. The numerical results show four different failure modes: dynamic fragmentation, single crack with branch, thermally induced cracks and cracks due to the combined effects of pressure and temperature. These results illustrate the important roles of thermal and mechanical loads with different time scales. Copyright © 2008 John Wiley & Sons, Ltd.
The stem cell niche
Authors: Walker MR , Patel KK , Stappenbeck TS
Published: October 2008

Virtually every tissue of the adult organism maintains a population of putatively slowly‐cycling stem cells that maintain homeostasis of the tissue and respond to injury when challenged. These cells are regulated and supported by the surrounding microenvironment, referred to as the stem cell ‘niche’. The niche includes all cellular and non‐cellular components that interact in order to control the adult stem cell, and these interactions can often be broken down into one of two major mechanistic categories—physical contact and diffusible factors. The niche has been studied directly and indirectly in a number of adult stem cell systems. Herein, we will first focus on the most well‐understood niches supporting the germline stem cells in the lower organisms Caenorhabditis elegans and Drosophila melanogaster before concentrating on the more complex, less well‐understood mammalian niches supporting the neural, epidermal, haematopoietic and intestinal stem cells. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Comparative proteomics profile of osteoblasts cultured on dissimilar hydroxyapatite biomaterials: An iTRAQ‐coupled 2‐D LC‐MS/MS analysis
Authors: Xu Jinling , Khor Khiam Aik , Sui Jianjun , Zhang Jianhua , Tan Tuan Lin , Chen Wei Ning
Published: October 2008

Hydroxyapatite (HA) and its derived bioceramic materials have been widely used for skeletal implants and/or bone repair scaffolds. It has been reported that carbon nanotube (CNT) is able to enhance the brittle ceramic matrix without detrimental to the bioactivity. However, interaction between osteoblasts and these bioceramics, as well as the underlying mechanism of osteoblast proliferation on these bioceramic surfaces remain to be determined. Using iTRAQ‐coupled 2‐D LC‐MS/MS analysis, we report the first comparative proteomics profiling of human osteoblast cells cultured on plane HA and CNT reinforced HA, respectively. Cytoskeletal proteins, metabolic enzymes, signaling, and cell growth proteins previous associated with cell adhesion and proliferation were found to be differentially expressed on these two surfaces. The level of these proteins was generally higher in cells adhered to HA surface, indicating a higher level of cellular proliferation in these cells. The significance of these findings was further assessed by Western blot analysis. The differential protein profile in HA and CNT strengthened HA established in our study should be valuable for future design of biocompatible ceramics.
Multi‐constraint computational design suggests that native sequences of germline antibody H3 loops are nearly optimal for conformational flexibility
Authors: Babor Mariana , Kortemme Tanja
Published: October 2008

The limited size of the germline antibody repertoire has to recognize a far larger number of potential antigens. The ability of a single antibody to bind multiple ligands due to conformational flexibility in the antigen‐binding site can significantly enlarge the repertoire. Among the six complementarity determining regions (CDRs) that generally comprise the binding site, the CDR H3 loop is particularly variable. Computational protein design studies showed that predicted low energy sequences compatible with a given backbone structure often have considerable similarity to the corresponding native sequences of naturally occurring proteins, indicating that native protein sequences are close to optimal for their structures. Here, we take a step forward to determine whether conformational flexibility, believed to play a key functional role in germline antibodies, is also central in shaping their native sequence. In particular, we use a multi‐constraint computational design strategy, along with the Rosetta scoring function, to propose that the native sequences of CDR H3 loops from germline antibodies are nearly optimal for conformational flexibility. Moreover, we find that antibody maturation may lead to sequences with a higher degree of optimization for a single conformation, while disfavoring sequences that are intrinsically flexible. In addition, this computational strategy allows us to predict mutations in the CDR H3 loop to stabilize the antigen‐bound conformation, a computational mimic of affinity maturation, that may increase antigen binding affinity by preorganizing the antigen binding loop. In vivo affinity maturation data are consistent with our predictions. The method described here can be useful to design antibodies with higher selectivity and affinity by reducing conformational diversity. Proteins 2009. © 2008 Wiley‐Liss, Inc.
Natural history of the E1‐like superfamily: Implication for adenylation, sulfur transfer, and ubiquitin conjugation
Authors: Burroughs A. Maxwell , Iyer Lakshminarayan M. , Aravind L.
Published: October 2008

The E1‐like superfamily is central to ubiquitin (Ub) conjugation, biosynthesis of cysteine, thiamine, and MoCo, and several secondary metabolites. Yet, its functional diversity and evolutionary history is not well understood. We develop a natural classification of this superfamily and use it to decipher the major adaptive trends occurring in the evolution of the E1‐like superfamily. Within the Rossmann fold, E1‐like proteins are closest to NAD(P)/FAD‐dependent dehydrogenases and S‐AdoMet‐dependent methyltransferases. Hence, their phosphotransfer activity is an independent catalytic “invention” with respect to such activities seen in other Rossmannoid folds. Sequence and structure analysis reveals a striking diversity of residues and structures involved in adenylation, sulfotransfer, and substrate binding between different E1‐like families, allowing us to predict previously uncharacterized functional adaptations. E1‐like proteins are fused to several previously undetected domains, such as a predicted sulfur transfer domain containing a novel superfamily of the TATA‐binding protein fold, different types of catalytic domains, a novel winged helix‐turn‐helix domain and potential adaptor domains related to Ub conjugation. On the basis of these fusions, we develop a generalized model for the linking of E1 catalyzed adenylation/thiolation with further downstream reactions. This is likely to involve a dynamic interplay between the E1 active sites and diverse fused C‐terminal domains. We also predict participation of E1‐like domains in previously uncharacterized bacterial secondary metabolism pathways, new cysteine biosynthesis systems, such as those associated with archaeal O‐phosphoseryl tRNA, metal–sulfur cluster assembly (e.g., in nitrogen fixation) and Ub‐conjugation. Evolutionary reconstructions suggest that the last universal common ancestor contained a single E1‐like domain possessing both phosphotransfer and thiolating activities and participating in multiple sulfotransfer reactions. The E1‐like superfamily subsequently expanded to include 26 families clustering into three major radiations. These are broadly involved in Ub activation, cofactor and cysteine biosynthesis, and biosynthesis of secondary metabolites. In light of this, we present evidence that in eukaryotes other E1‐like enzymes such as Urm1 were independently recruited for Ubl conjugation, probably functioning without conventional E2‐like enzymes. Proteins 2009. © 2008 Wiley‐Liss, Inc.
Specials: a financial warning!
Authors: Klein Leslie , Riley Genine , DasGupta Mark
Published: October 2008

An analysis of specials prescribing in one PCT found the average cost to be £102, with prices reaching over £2000. The authors suggest how the expense of prescribing specials can be kept to a minimum. Copyright © 2008 Wiley Interface Ltd
Charge ordering in EDO‐TTF salts and their optical spectra: toward the first‐principles understanding of photoinduced phase transition
Authors: Iwano Kaoru , Shimoi Yukihiro
Published: October 2008

A new scheme to calculate the ground and excited states of molecular crystals has been proposed for the purpose of studying their photoinduced phase transitions and demonstrated in a quasi‐one‐dimensional compound, (EDO‐TTF)2PF6, by the present authors [Phys. Rev. B 77, 075120 (2008)]. The principal results in that paper have been the successfully reproduced (0110)‐type charge ordering in the ground state and the optical conductivity spectrum consistent with the observed one.

In this article, we explain technical and scientific details that have not been touched in the previous paper. In particular, we are concerned with the validity of our scheme; a cluster calculation augmented by self‐consistent environmental charges. The detailed behavior of the convergence of the self‐consistency is discussed. In addition, its effectiveness in other cases is also checked, with the high‐temperature phase as the first extension. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Charge transfer processes in cyano‐bridged transition metals
Authors: Kamioka Hayato , Moritomo Yutaka , Kosaka Wataru , Ohkoshi Shin‐ichi
Published: October 2008

We have applied a time‐resolved absorption spectroscopy to investigate the charge transfer (CT) processes in the Prussian Blue‐type cyanides MII[FeIII(CN)6]0.675H2O (M = Mn, Co) embedded in a Nafion film. In the Mn‐Fe cyanide, we observed the bleaching of the CT band at 2.4 eV, similar to that found in the Co‐Fe cyanide.

We found that the lifetime of the photo‐induced CT state in Mn‐Fe cyanide shows significant dependence on the excitation photon energy. This is in sharp contrast to the case of the Co‐Fe cyanide. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of external magnetic field and confinement on spectrum rearrangement and exciton polaritons in optical microcavity
Authors: Kaputkina Natalia , Lozovik Yuri
Published: October 2008

Influence of external magnetic field and confinement on direct and spatially‐indirect excitons is studied. Exciton‐photon interaction and exciton polariton formation are discussed for single and coupled quantum wells or quantum dots embedded in optical microcavity. Possibility to control polariton resonance, polariton splitting and polariton dispersion by magnetic field is studied analitically and numerically. Magnetic field changes effective mass of magnetoexciton. Magneticfield increases effective steepness of confining potential in quantum dots also. This leads to the transformation of exciton energy spectrum. At low temperatures spontaneous coherence and Kosterlitz‐Thouless transition to superfluid state of exciton polaritons in the system of coupled quantum wells embedded in microcavity or Bose‐Einstein condensation of exciton polaritons in the system of coupled quantum dots embedded in optical microcavity can take place. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical studies of hydrogenbonded dielectrics TlH2PO4
Authors: Kawai Taketoshi , Ohno Nobuhito
Published: October 2008

We have for the first time investigated optical properties of thallium dihydrogen phosphate TlH2PO4 (TDP) up to vacuum ultraviolet energy region at low temperature. The remarkable dispersion‐like structures due to the first exciton transitions are observed around 5.8 eV above the fundamental absorption edge at 5.2 eV. The origin of the first excitons in TDP is ascribed to the cationic transition from 6s2 to 6s 6p electronic states in Tl+ ions.

In the higher energy region, characteristic peak structures appear at 15.6 and 16.7 eV. The peak structures are attributed to the core excitons based on the transitions from 5d106s2 to 5d96s26p states in Tl+ions. A broad luminescence band with a large Stokes shift is observed at 2.9 eV, stimulated efficiently at the first exciton transition region. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photoluminescence of forsterite single crystals excited by vacuum ultraviolet radiation
Authors: Kitaura Mamoru , Ohnishi Akimasa
Published: October 2008

Emission and excitation spectra of forsterite have been measured using synchrotron radiation. The 2.55 eV and 2.85 eV bands dominates the emission spectra under excitation above and below the fundamental absorption edge at 7.6 eV, respectively. From the feature of excitation spectra, the 2.55 eV band is assigned to an intrinsic origin in forsterite. That is, this band most likely originates from a self‐trapped exciton (STE) state. The 2.85 eV band is ascribed to an extrinsic origin such as imperfections. The excitation spectrum for the 2.55 eV band exhibits the threshold for the electron‐hole (e ‐h) multiplication at around 21 eV, which is caused by inelastic scattering of hot photoelectrons with valence electrons. The structure of STEs and e ‐h relaxation processes induced by vacuum ultraviolet (VUV) photons are discussed on the basis of a comparison of experiment and theoretical calculation. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optically induced lattice distortion and its spatial diffusion in the relaxed excited state of a quantum paraelectric material
Authors: Kohmoto T. , Hatano N. , Yamaki M. , Koyama Y. , Moriyasu T.
Published: October 2008

We have investigated the diffusion dynamics of the optically induced lattice distortion in the quantum paraelectric region of strontium titanate SrTiO3. The time evolution of the lattice distortion, which is accompanied by the polarization in the relaxed excited state, was observed by using the polarization spectroscopy with the pump‐probe technique. The observed signal of the optically induced lattice distortion has a component which decays in the nanosecond region.

The decay curve of the lattice distortion depends on the beam diameter. The relaxation time becomes shorter as the beam diameter is decreased. We observed the lattice distortion induced by the separated pump beam from the probe beam. The signal of the lattice distortion appears later as the separation between the pump and probe beams becomes larger. These experimental results suggest that the optically induced lattice distortion diffuses spatially. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cavity polariton dispersion of a single‐crystalline anthracene film embedded in a microcavity
Authors: Kondo H. , Tongu K. , Yamamoto Y. , Yamamoto S. , Kurisu H.
Published: October 2008

We study anisotropic behavior of cavity polaritons in an organic microcavity composed of a single crystalline anthracene film grown into the gap of the Fabry‐Perot cavity by a method through capillary action. The anisotropic response of the cavity polariton appeared on the spectra depending on the linear polarized directions; two kinds of the polarization correspond to the principal axes of anthracene crystal. Transmission spectra were measured with various thickness of the anthracene film. The peak‐shift of the lower polariton mode depending on the thickness was obviously observed, whereas that of the upper polariton mode was not clearly observed be cause of the complicated shape of the spectra. This behavior for the upper polariton mode was analyzed on the basis of the convolution between the spectra of the cavity mode and the absorption due to the vibronic transition in anthracene. Cavity‐polariton dispersion as a function of thickness was obtained from peak‐shift on the spectra. Each thickness was determined by spectral fitting through calculation using the transfer matrix theory. Large vacuum Rabi splitting energies of this system were obtained from the dispersion as 0.20 and 0.34 eV for two kinds of the polarizations. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Exciton and biexciton properties in GaN nanocolumn: dependence on morphology and diameter
Authors: Kouyama Kazuaki , Inoue Masaya , Inose Yuta , Suzuki Naoki , Kunugita Hideyuki , Ema Kazuhiro , Sekiguchi Hiroto , Kikuchi Akihiko , Kishino Katsumi
Published: October 2008

We have investigated how the morphology and diameter of GaN nanocolumn affect the optical properties of exciton and biexciton. We measured photoluminescence (PL) of excitons in GaN nanocolumns at low temperature and found that the PL spectra depend on the column diameter. Changing the distance between the sample and the collimating lens, it was established that this phenomenon is due to the z ‐polarized PL radiated from the side surface. This result proves that the nano‐scale morphology produces a change in the optical properties. In addition, to elucidate the mechanism causing the increase of the biexciton binding energy observed in a previous experiment, we calculated the exciton binding energies by the variational method and also estimated their sizes. From the calculated results we can expect that the only biexcitons experience spatial confinement effect even when the nanocolumn width is much larger than the exciton Bohr radius. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dynamics of nuclear wave packet in the excited state of KCl F centers
Authors: Koyama Takeshi , Nakajima Makoto , Suemoto Tohru
Published: October 2008

Dynamics of nuclear wave packet at the F center in KCl at 5 K is investigated by frequency up‐conversion spectroscopy. The oscillation frequency of the nuclear wave packet is 6.0 THz, which lies in the LO phonon branch near the Γ point of the Brillouin zone. The luminescence intensities decay slower in the low energy side of the stationary luminescence spectrum than in the high energy side. The transient luminescence spectra show relatively high intensities in the low energy side. These two features indicate the existence of the second 2s ‐2p level crossing near the relaxed excited state. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photo‐induced effect in quantum paraelectric materials: Transient birefringence measurement
Authors: Koyama Y. , Moriyasu T. , Okamura H. , Yamada Y. , Tanaka K. , Kohmoto T.
Published: October 2008

The photo‐induced effects in quantum paraelectric materials, strontium titanate SrTiO3 and Ca‐doped SrTiO3, are investigated. The observed birefringence for Cadoped SrTiO3 shows that an optical anisotropy along the [100] axis is generated by the ultraviolet (UV) illumination. The transient birefringence in a pulsed electric field is studied to probe the dynamical property of the polarization under dark and UV illumination.

Under the UV illumination, the change of birefringence is reduced, and the dielectric response of relaxation type was observed both in SrTiO3 and in Ca‐doped SrTiO3. It was found that the ferroelectric phase transition temperature is shifted toward the lower temperature side under the UV illumination. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electron‐phonon effect on excitons in quasi‐2D ternary mixed crystal of polar semiconductors
Authors: Liang X. X. , Song Tie‐Lei
Published: October 2008

The electron‐phonon effect on quasi‐two‐dimensional (2D) Wannier excitons in ternary mixed crystal systems of polar semiconductors is studied. The binding energy of the 2D exciton is variationally calculated and the numerical results for several II‐VI and III‐V as well as III‐nitride compound semiconductors are given. The results show more remarkable electron‐phonon effect in 2D systems than that in three‐dimensional (3D) case. The obvious nonlinearity of the electron‐phonon interaction contributions to exciton binding energies is also theoretically found, in special for the systems composed of nitride‐base compounds. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Engineering molecular aggregate spectra
Authors: Malyshev V. A. , Malyshev A. V.
Published: October 2008

We show that optical properties of linear molecular aggregates undergo drastic changes when aggregates are deposited on a metal surface. The dipole‐dipole interactions of monomers with their images can result in strong re‐structuring of both the exciton band and the absorption spectrum, depending on the arrangement of the monomer transition dipoles with respect to the surface. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of disorder on the relaxation of photoexcited states in one‐dimensional Mott insulators
Authors: Segawa Mami , Takahashi Akira , Aihara Masaki
Published: October 2008

We theoretically investigate the effect of static disorder on the dynamics of photoexcited states in onedimensional Mott insulators. We adopt the Pariser‐Parr‐Pople model, where disorder is introduced in the site energy and the transfer integral. We numerically calculate the time development of the state excited by a light pulse, and investigate the time dependence of the nearest‐neighbor spin‐spin interaction energy, the on‐site Coulomb interaction energy, and the kinetic energy of photogenerated charges. In the weaker excitation case, the energy transfer from the charge degrees of freedom to the spin degrees of freedom does not occur in the regular systems as a result of the spin‐charge separation. When the disorder in the transfer integral is introduced, the spin‐spin interaction energy changes with time after photoexcitation, showing that the spin‐charge coupling is induced in this case.

The effects of the disorder in the site energy on the spincharge coupling are much weaker than those in the transfer integral. On the contrary, the energy transfer from the on‐site Coulomb interaction energy to the kinetic energy is strongly suppressed by these two kinds of disorders. In the stronger excitation case, the spin and the charge degrees of freedom are coupled in the photoexcited states, and the two kinds of energy transfers occur even in regular systems. Furthermore, these energy transfers occur in irreversible way, suggesting that these transfers are relaxation phenomena. These relaxations are enhanced by the disorders. There are no significant differences in the effects of disorders on these relaxations between the disorder in the site energy and that in the transfer integral. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Polaron effect on the binding energies of excitons in quantum wells under hydrostatic pressure
Authors: Zhao G. J. , Liang X. X. , Ban S. L.
Published: October 2008

Under hydrostatic pressure, the polaron effect on the binding energies of excitons in quantum wells is discussed by a variational method by considering the influence of finite barriers and the coupling of an exciton with bulk confined longitudinal optical, half space longitudinal optical and interfacial optical modes. A quasi‐ two dimensional Lee‐Low‐Pines like unitary transformation is adopted to deal with the exciton‐phonon interaction and the pressure dependence of physical parameters is also taken into account in the calculation. As an example, the numerical computation is applied to the GaAs/Alx Ga1–x As quantum wells. The result shows that the exciton binding energies increase with presure from 0 to 40 kbar. The maximum energy shift is about 21% for the given quantum well width and Al concentration x = 0.15. The exciton‐phonon interaction energies also increase with pressure and the effects of three kinds of different exciton‐phonon interactions are discussed in detail for different widths of quantum wells. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Revisiting the foundations of the quantum theory of atoms in molecules: Toward a rigorous definition of topological atoms
Authors: Nasertayoob Payam , Shahbazian Shant
Published: October 2008

An explicit classification of consistent variational constraints within the context of the “quantum theory of proper open subsystems” as well as the “quantum theory of atoms in molecules” (QTAIM) it presented. It is demonstrated that the general variational procedure is not sensitive enough to discriminate between different mathematically consistent variational conditions. The uniqueness of the regional kinetic energy is employed to derive the net zero‐flux condition and the regions satisfying this condition are named asquantum divided basins. A modified form of the local zero‐flux is proposed in order to define topological atoms within the context of the orthodox QTAIM. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Calculation of ionization potential and chemical hardness: A comparative study of different methods
Authors: Shankar R. , Senthilkumar K. , Kolandaivel P.
Published: October 2008

The suitability of ab initio and density functional theory (DFT) methods for an accurate determination of ionization potential and chemical hardness is the subject of systematic analysis for a panel of molecules. Comparison of experimental ionization potential values with theoretical results indicates that using orbital energies obtained from the so‐called statistical average of orbital potential (SAOP) model exchange correlation potential in Koopman's theorem is an efficient method to evaluate the correct ionization potentials. Experimental ionization potential and electron affinity values have been used to calculate the absolute chemical hardness. Comparative results show that the chemical hardness values calculated by using Hartree–Fock orbital energies in Koopman's theorem are sufficiently good rather than Möller–Plesset second order perturbation method and DFT‐generalized gradient approximation (GGA) exchange correlation functional orbital energies. A new method given by Tozer et al. (J Phys Chem A 2005, 109, 8923) to calculate the chemical hardness works well with the orbital energies of DFT‐GGA functionals together with the ionization potential values calculated from SAOP orbital energies. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Theoretical study on interactions between thiourea S‐monoxide and water
Authors: Peng Ke , Yang Wen , Zhou Weiqun
Published: October 2008

This work investigated the hydrolyzation of thiourea monoxide using density functional theory (DFT) and Møller–Plesset second‐order (MP2) Theory. We obtained the equilibrium structures and other molecular properties of the clusters. The results show that thiourea monoxide has a good solubility in water solvent, and as indicated, the binding energies of the clusters are increased progressively by the addition of water molecules. Furthermore, the increases of the distance(CS) and (SO) by the addition of water molecules indicate that the strength of the CS and SO bonds are weakened. When n = 7 (n, the number of water molecules), the CS bonds of Clusters VII ruptured. We conclude that thiourea monoxide can be decomposed in aqueous solution. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
A guiding simulation research on developing promising energetic materials
Authors: Liu Min‐Hsien , Cheng Ken‐Fa , Chen Cheng , Hong Yaw‐Sun
Published: October 2008

This investigation is motivated by the representative synthesis reaction of 1,4,5,8‐tetranitro‐1,4,5,8‐tetraazadecalin (TNAD): ethylene diamine is replaced by 1,1,diamino‐2,2‐dinitroethene (FOX‐7) or 1,3,5‐triamino‐2,4,6‐trinitrobenzene (TATB) to react with glyoxal in order to subsequently obtain promising high energy density materials. The hybrid density functional theory method is used in calculations for some series of compounds with NNO2 and CNO2 functional groups. First, we create the corresponding Cartesian coordinates of the molecules under investigation and obtain their optimized molecular geometry; the molecular enthalpy can then be used to calculate the molecular detonation heat upon explosion. Furthermore, the target molecular volumes are obtained using the group additivity approach, which are then transferred into molecular densities. The densities and detonation heats of the corresponding energetics are carried into the Kamlet–Jacobs empirical equations to determine the related detonation velocities and detonation pressures. It was found that 10 of 14 TATB‐ and FOX7‐related molecular derivatives have detonation velocities between 9,302 and 1,1122 m/s and between 396 and 646 kbar, and are superior in performance to the traditional octahydro‐1,3,5,7‐tetranitro‐1,3,5,7‐tetrazocine (HMX) explosive. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Stability analysis of the neutral noble gas molecules FNgX and their anions FNgX− (Ng = He, Ar, Kr; X = O, S)
Authors: Li Yun , Ai Hongqi , Qi Zhongnan , He Wei , Zhang Liang
Published: October 2008

The structural stability and bonding energies of the neutral noble gas molecules FNgX and their anions FNgX− (Ng = He, Ar, Kr; X = O, S) are discussed at the CCSD(T)/aug‐cc‐pVnZ (n = D, T) levels. Results reveal that only two neutral FKrX molecules are stable, whereas their FHeX and FArX counterparts are not. All their anions are stable and the stability mainly derives from the contribution of the extra electron, i.e., the attachment of the electron greatly enhances the orbital interactions of two bonds, FNg and NgX. Different from the anion counterparts, the electrostatic interaction energy plays a crucial role in the FKrX stability. Compared with those unstable FHeX and FArX counterparts, the enough charge distribution over each atom of FKrX ensures the effective bonding between F and Kr, and between Kr and X, consequently strengthen the stability of the neutral FKrX (X = O, S) structures. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
A design tool for planning emulsified oil‐injection systems
Authors: Weispfenning Aaron M. , Borden Robert C.
Published: October 2008

Emulsified oils have been used to stimulate anaerobic bioremediation at hundreds of sites contaminated with chlorinated solvents, perchlorate, heavy metals, and nitrate. A simple spreadsheet‐based tool has been developed to assist in the design of injection‐only systems for distributing emulsified oils in barriers and area treatments. This tool allows users to quickly compare the relative costs and performance of different injection alternatives and identify a design that is best suited to site‐specific conditions. Contact efficiency is estimated using results of prior numerical model simulations and dimensionless scaling factors that relate the volume of oil and water injected to treatment‐zone dimensions. Sensitivity analysis results indicate that maximum oil retention is one of the most important factors controlling system performance and cost. © 2008 Wiley Periodicals, Inc.
Residential vapor‐intrusion evaluation: Long‐duration passive sampling vs. short‐duration active sampling
Authors: Odencrantz Joseph E. , O'Neill Harry , Steinmacher Shirley J. , Case Jarrod D. , Johnson Paul C.
Published: October 2008

Sampling indoor air for potential vapor‐intrusion impacts using current standard 24‐hour sample collection methods may not adequately account for temporal variability and detect contamination best represented by long‐term sampling periods. Henry Schuver of the U.S. Environmental Protection Agency Office of Solid Waste stated at the September 2007 Air & Waste Management Association vapor‐intrusion conference that the US EPA may consider recommending longer‐term vapor sampling to achieve more accurate time‐weighted‐average detections.

In November 2007, indoor air at four residences was sampled to measure trichloroethene (TCE) concentrations over short‐ and long‐duration intervals. A carefully designed investigation was conducted consisting of triplicate samplers for three different investigatory methods: dedicated 6‐liter Summa canisters (US EPA Method TO‐15), pump/sorbent tubes (US EPA Method TO‐17), and passive diffusion samplers (MDHS 80). The first two methods collected samples simultaneously for a 24‐hour period, and the third method collected samples for two weeks.

Data collected using Methods TO‐15 (canisters) and TO‐17 (tubes) provided reliable short‐duration TCE concentrations that agree with prior 24‐hour sampling events in each of the residences; however, the passive diffusion samplers may provide a more representative time‐weighted measurement. The ratio of measured TCE concentrations between the canisters and tubes are consistent with previous results and as much as 28.0 μg/m3 were measured. A comparison of the sampling procedures, and findings of the three methods used in this study will be presented. © 2008 Wiley Periodicals, Inc.
Active mode observation of switching systems based on set‐valued estimation of the continuous state
Authors: Baglietto M. , Battistelli G. , Scardovi L.
Published: October 2008

Mode observability is addressed for a class of discrete‐time linear systems that may switch in an unknown and unpredictable way among different modes taken from a finite set. The possiblea prioriknowledge on the continuous state of the system and the presence of unknown but bounded noises affecting both the system and the measurement equations are explicitly taken into account. The mode observation is performed ‘actively’: control sequences (discerning control sequences) are searched, which allow to identify the switching sequence on the basis of the observations. Conditions that characterize discerning controls in a finite‐horizon setting are obtained. Moreover, a procedure is proposed in order to derive ‘persistently discerning’ control sequences (over an infinite horizon). A numerical example is reported to clarify the approach. Copyright © 2008 John Wiley & Sons, Ltd.
Real‐time ultrasound vs. evaluation of static images in the preoperative assessment of adnexal masses
Authors: Van Holsbeke C. , Yazbek J. , Holland T. K. , Daemen A. , De Moor B. , Testa A. C. , Valentin L. , Jurkovic D. , Timmerman D.
Published: October 2008

Objective

To determine if the prediction of the malignancy of an adnexal mass using pattern recognition, i.e. subjective evaluation of gray‐scale and Doppler ultrasound findings, is as accurate when based on static images as it is when based on a real‐time ultrasound examination.

Methods

The static images of 166 non‐consecutive patients with ‘difficult’ adnexal masses, who all underwent surgery and for whom a histopathological diagnosis was available, were evaluated by three experts in gynecological ultrasound (‘image experts’). All ultrasound examinations had been performed and the static images saved by a fourth expert sonologist (‘real‐time’ sonologist). All four sonologists classified the adnexal masses as benign or malignant based on their subjective impression and stated with what degree of confidence their diagnosis was made. The diagnostic performance of the real‐time sonologist was compared with that of each of the three image experts and with that of the ‘consensus opinion’ of the image experts (i.e. the diagnosis suggested by at least two of the latter).

Results

The real‐time sonologist correctly predicted the diagnosis with an accuracy of 89% (148/166) vs. 85% (141/166) for the consensus opinion of static images (P = 0.0707). Equivalent values for sensitivity and specificity were 80% (56/70) vs. 83% (58/70) (P = 0.4142) and 96% (92/96) vs. 86% (83/96) (P = 0.0027), respectively.

Conclusions

The preoperative diagnosis of an adnexal mass made on the basis of a real‐time ultrasound examination is more precise than a diagnosis made on the basis of saved static ultrasound images. Evaluation of static images is associated with lower diagnostic specificity. Copyright © 2008 ISUOG. Published by John Wiley & Sons, Ltd.
Response of hatchling Komodo Dragons (Varanus komodoensis) at Denver Zoo to visual and chemical cues arising from prey
Authors: Chiszar David , Krauss Susan , Shipley Bryon , Trout Tim , Smith Hobart M.
Published: October 2008

Five hatchling Komodo Dragons (Varanus komodoensis) at Denver Zoo were observed in two experiments that studied the effects of visual and chemical cues arising from prey. Rate of tongue flicking was recorded in Experiment 1, and amount of time the lizards spent interacting with stimuli was recorded in Experiment 2. Our hypothesis was that young V. komodoensis would be more dependent upon vision than chemoreception, especially when dealing with live, moving, prey. Although visual cues, including prey motion, had a significant effect, chemical cues had a far stronger effect. Implications of this falsification of our initial hypothesis are discussed. Zoo Biol 28:29–34, 2009. © 2008 Wiley‐Liss, Inc.
Spatial and temporal summation of pain evoked by mechanical pressure stimulation
Authors: Nie HongLing , Graven‐Nielsen Thomas , Arendt‐Nielsen Lars
Published: October 2008

Chronic pain patients often suffer from widespread and long lasting pain. The integrative effect of combined spatial and temporal summation on pain intensity has not been quantitatively tested. The present study was designed to investigate: (1) if the size of the stimulation area would facilitate the temporal summation of pain to repetitive pressure stimulation, and (2) if temporal summation is effective when stimulating separated sites, repetitively. Twenty healthy male subjects participated in this study. The test sites were located on the bilateral upper trapezius and tibialis anterior muscles. The ten stimuli (each with a duration of 1s) were applied to a single site at three inter‐stimulus intervals (ISI: 1, 5, 30s) using five different probe sizes (0.5, 1, 2, 4 and 8cm2). The stimulation intensity was equal to the pressure pain threshold (PPT) determined for each probe size. Similar repetitive stimulations at two inter‐stimulus intervals (5s and 30s) using two sizes of probes (0.5cm2 and 2cm2) were applied to ten separate sites. The PPT at the trapezius muscle decreased significantly with the increase in stimulus area from 0.5cm2 to 8cm2 (P<0.001) due to spatial summation. Temporal summation of pain was evoked by repetitive pressure stimuli on the same site for all ISI and was more pronounced at 5s and 30s ISI with larger probe areas (2, 4, and 8cm2) compared to smaller probe areas. There was no temporal summation of pain to stimuli with ISI 5 and 30s when stimulating the separated sites. The current study indicated that spatial summation facilitated the temporal summation of pain for stimuli given at 5s and 30s ISI. The combination of temporal and spatial integration of nociceptive input facilitates the pain intensity, suggesting that temporal summation is clinically relevant in conditions with widespread pain.
A systematic review of randomized controlled trials of prenatal and postnatal vitamin A supplementation of HIV‐infected women
Authors: Kongnyuy Eugene Justine , Wiysonge Charles Shey , Shey Muki Shehu
Published: October 2008

We searched the Cochrane Library, MEDLINE, EMBASE, AIDSearch, and Gateway to assess the effect of prenatal and/or postnatal vitamin A supplementation on the risk of mother‐to‐child transmission (MTCT) of HIV and other pregnancy outcomes. We included 5 trials totaling 7528 women (4 trials of prenatal and 1 trial of postnatal supplementation). Overall, there was no evidence of an effect of prenatal and/or postnatal vitamin A supplementation on the risk of MTCT of HIV (Relative Risk [RR] 1.06, 95% Confidence Interval [CI] 0.89–1.26). However, prenatal vitamin A supplementation significantly improved birth weight (weighted mean difference 89.78; 95% CI, 84.73–94.83), but there was no evidence of an effect on stillbirths (RR 0.99; 95% CI, 0.68–1.43), preterm births (RR 0.88; 95% CI, 0.65–1.19), death before 24 months among live births (RR 1.08; 95% CI, 0.91–1.29), and maternal death (RR 0.83; 95% CI, 0.59–1.17). The available evidence does not support vitamin A supplementation of HIV‐infected pregnant and lactating women, despite improvement in birth weight.
Cesarean delivery surveillance system at a maternity hospital in Kabul, Afghanistan
Authors: Kandasamy Tharani , Merialdi Mario , Guidotti Richard J. , Betrán Ana P , Harris‐Requejo Jennifer , Hakimi Farima , Van Look Paul F. , Kakar F.
Published: October 2008

Objective

To use an active facility‐based maternal and newborn surveillance system to describe cesarean delivery practices and outcomes in a resource‐poor setting.

Methods

Using data from operating room logbooks, 392 cesarean deliveries were evaluated between April 1 and June 30 2006 at a large public maternity hospital in Kabul, Afghanistan.

Results

The perinatal mortality rate was 89 per 1000 births: 57% antepartum and 37% intrapartum stillbirths. Fetuses with normal birth weight comprised 85% of intrapartum stillbirths. Obstructed labor, uterine rupture, and malpresentation accounted for more than 50% of perinatal deaths. The cesarean delivery rate was 10.2% and there were 2 maternal deaths.

Conclusion

The high percentage of intrapartum stillbirths among normal birth weight fetuses suggests a need for improved labor monitoring and surgical obstetric practices. The use of a facility‐based perinatal surveillance system is critical in guiding such quality assurance initiatives.
WOMEN’S AUTONOMY AND REPRODUCTIVE PREFERENCES IN ERITREA
Authors: WOLDEMICAEL GEBREMARIAM
Published: October 2008

Current research and policies on reproductive behaviours in many East African countries focus primarily on proxy indicators of women’s autonomy, and very little emphasis is placed on direct indicators of women’s autonomy. In this paper, data from the 2002 Eritrea Demographic and Health Survey (EDHS) are used to address some of the most frequently raised questions about the link between women’s autonomy and reproductive behaviour. The results from the multivariate logistic models show that although the relationship between women’s autonomy and reproductive preferences in Eritrea is complex, some clear, broad patterns exist that have implications for theory and policy. First, although the different dimensions of women’s autonomy influence the outcome variables differently in terms of magnitude and statistical significance, most of them have a strong connection; in particular, women’s final say in decisions regarding day-to-day household purchases and spousal communication are significant explanatory variables in fertility preferences and ever-use of modern contraception. Second, many background (proxy) variables, particularly household economic condition and employment, exert a strong and independent influence over fertility preferences and ever-use of contraception regardless of a woman’s autonomy. In their relationship to reproductive behaviours, therefore, employment and economic status cannot be considered as proxies for women’s autonomy in Eritrea. A complete explanation of the relationship between women’s autonomy and reproductive preferences must recognize the effects of both the background and direct autonomy indicators. Interventions are needed to improve women’s decision-making autonomy and strengthen their negotiating capacity on family planning if an increased desire to limit fertility is to be attained.
A comparison of management practices, farmer-perceived disease incidence and winter housing on organic and non-organic dairy farms in the UK
Authors: Langford Fritha M , Rutherford Kenneth MD , Jack Mhairi C , Sherwood Lorna , Lawrence Alistair B , Haskell Marie J
Published: October 2008

There have been increases in the number of organic dairy farms in the UK in recent years. However, there is little information on the impact of organic regulations on cow welfare. As part of a larger study, we aimed to investigate differences between organic and non-organic farms in management practices and winter housing quality. Forty organic and 40 non-organic farms throughout the UK were visited. Organic and non-organic farms were paired for housing type, and as far as possible for herd size, genetic merit and location. A detailed questionnaire covering key aspects of dairy management was carried out with each farmer. On a subset of twenty pairs, an assessment of the quality of the winter housing for both lactating and dry cows was undertaken, covering the parlour, bedding, loafing and feeding areas. Management practices and building conditions varied greatly within farm types and there was considerable overlap between organic and non-organic farms. Milk yield, level and composition of concentrate feed, management of heifers and calving, and use of ‘alternative treatments’ to prevent and treat mastitis differed between organic and non-organic farms. In all other respects there were no differences between farm types. Building dimensions per cow did not differ, even though organic recommendations advise greater space per cow than recommended for non-organic farms. The similarity between organic and non-organic farms in most respects indicates that cow housing and health, based on both the described management regimes and the farmers' perceptions of disease incidence, on organic dairy farms is neither compromised by the regulations, nor considerably better than on non-organic farms.