bluuebunny/crossref_metadata_2025_split huggingface dataset:
Linear and nonlinear magneto‐optical response of ultrathin Co/Au/Mo and Co/Mo films grown on sapphire substrates
Authors: Stupakiewicz A. , Kirilyuk A. , Maziewski A. , Rasing Th. , Wawro A. , Baczewski L. T. 
Published: July 2008

AbstractWe report studies of the linear and nonlinear magneto‐optical properties of epitaxial ultrathin Co films grown on sapphire substrates covered with Mo or Mo/Au buffers. Changes of the crystallographic symmetry and magnetization of buried interfaces were deduced from the magneto‐optical Kerr effect hysteresis loops and magnetization‐induced second‐harmonic generation (MSHG). Depending on the buffer, two‐fold (for Mo buffer) or six‐fold (for Mo/Au buffer) symmetries were observed in both inplane magnetic anisotropy and MSHG intensity. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Preparation of thin ferrite films on silicon using RF sputtering
Authors: Koblischka M. R. , Kirsch M. , Brust M. , Koblischka‐Veneva A. , Hartmann U. 
Published: July 2008

AbstractThin‐films of Nix Zn1–x Fe2O4 [(Ni,Zn)‐ferrite] are grown by means of RF sputtering on Si(100) and (111) substrates, corresponding to the orientation of Si cantilevers for AFM/MFM measurements. We find that the ferrite can be sputtered directly onto the Si surfaces, but an additional annealing step is required to obtain a purely polycrystalline, soft magnetic film. The microstructure of the films is investigated employing transmission electron microscopy, electron backscatter diffraction and magnetic force microscopy. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Zn–In–O based thin‐film transistors: Compositional dependence
Authors: Itagaki N. , Iwasaki T. , Kumomi H. , Den T. , Nomura K. , Kamiya T. , Hosono H. 
Published: July 2008

AbstractThe compositional dependence of sputter‐deposited Zn–In–O (ZIO) film properties and the TFT performance were studied by means of a combinatorial technique. Both the characteristics of ZIO‐TFTs and the ZIO film properties are very sensitive to the Zn:In ratio. The best TFT performances are obtained at Zn:In ∼60:40 at%, where the saturation mobility (μsat), subthreshold swing (S.S.), on–off current ratio (Ion/Ioff), and threshold voltage (Vth) are 26.5 cm2/V s, 0.24 V/dec., 1010, and +2 V, respectively. The TFT characteristics peak at this compositional ratio. Specifically, μsat, Ion/Ioff and Vth reach maximum, while S.S. reaches minimum at this ratio. The air stability of ZIO‐TFTs was also examined for active channel layers with different Zn:In ratios, which clarified that the TFTs with high stability are obtained around the same composition ratio where the best characteristics are obtained. It was confirmed by X‐ray diffraction and transmission electron microscopy that the ZIO films with this composition ratio have amorphous structure. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Lithium mobility in complexes Li[Cn]1 (n = 5−21): PES analysis in different stationary points
Authors: Balashov A. M. , Ermilov A. Yu. , Scherbinin A. V. 
Published: July 2008

AbstractThe equilibrium geometries of the cylinder‐like lithium hydrocarbon complexes Li[Cn]1 (n = 7–12) are calculated within Density Functional Theory(DFT) with PBE0 exchange‐correlation potential. The 6‐31 G* basis was set on carbon and lithium atoms while STO‐3G one was chosen for hydrogens. The tendencies found for complexes with n = 7–12 gets broken and transforms to asymptotic behavior in range of n > 13. The large complexes possess the structure where lithium is placed at the carbon hexagon center area and close to C2v symmetry. Opposite, for n = 5–6 lithium is placed on the high symmetry axis of initial hydrocarbon. Several stationary points of complexes with n = 8–21, defined by lithium location under the hexagon center (1), under the CC bond center (2) and at the hydrocarbon skeleton center (3) were found. The migration barriers between stationary points (1)–(3) were estimated. The type (3) structures are distinctly higher of energy than (1) and (2), at that the difference is increased according to growing of n. The complexes with n < 13 are characterized by usual charge transfer from metal to hydrocarbon skeleton, for n ≥ 13 the molecular‐like solution is occurred. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Simultaneous σ‐hole and hydrogen bonding by sulfur‐ and selenium‐containing heterocycles
Authors: Murray Jane S. , Lane Pat , Politzer Peter 
Published: July 2008

AbstractWhen a Group V, VI, or VII atom forms a covalent bond, its bonding orbital has a deficiency of electronic charge in its outer (noninvolved) lobe. This is called a σ‐hole. If the atom is sufficiently polarizable, the σ‐hole may have a positive electrostatic potential which can interact with a nucleophilic site in its proximity to form a noncovalent bond. In this article, we show computationally, for a series of sulfur and selenium heterocycles, how the two σ‐holes on each S or Se atom are affected by changes in the molecular framework and substituents. It is possible to selectively design σ‐holes of appropriate strength and orientation for specific purposes, e.g. drug‐receptor interactions or crystal engineering. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Shifts of the hydrogen atom in a cylindrical cavity
Authors: Yurenev P. V. , Scherbinin A. V. , Pupyshev V. I. 
Published: July 2008

AbstractHydrogen atom in a cylindrical cavity is the simplest model for describing electronic states of the atom encapsulated into the nanotube. In the present work, simple analytical estimates for the electronic energy change under longitudinal and transversal shifts of the nucleus are made, using the first‐order perturbation theory with the radius of the cavity as a perturbation parameter. Predicted signature of the electronic energy for the variety of atomic states agrees in essential details with the direct numerical estimations by finite difference and collocation procedures. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
PO → Si intramolecular coordination in the derivatives of 1,4‐phosphasilacyclohexane 1‐oxides
Authors: Shainyan Bagrat A. , Lazareva Natalia F. 
Published: July 2008

AbstractThe chair and boat conformers for a series of derivatives of 1,4‐phosphasilacyclohexane 1‐oxides have been calculated at the B3LYP/6‐311+G** level of theory in the gas phase and taking into account the effect of solvent polarity using the IEF‐PCM model. The stability of the boat conformers containing pentacoordinate silicon due to formation of the PO→Si intramolecular coordination bond depends on the environment of the phosphorus atom and polarity of the solvent, and the strength of the transannular bond depends also on the nature of the substituents at the silicon atom. The highly polar boat conformers are strongly stabilized in the DMSO solution. NBO analysis showed the importance of the σ(CSi)→σ*(H3CN) hyperconjugative interaction in the two H3CNCSi fragments of the ring favoring the formation of the pentacoordinate silicon atom. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Temperature effects on polaron stability in polyacetylene
Authors: da Cunha Wiliam Ferreira , de Oliveira Neto Pedro Henrique , Gargano Ricardo , Magela e Silva Geraldo 
Published: July 2008

AbstractIn this work, we investigate the influence of the temperature imposed to a system initially composed of a free polaron moving through a trans‐polyacetylene chain. Our approach uses a version of the Su, Schrerieffer, and Heeger model where we included temperature effects on the lattice in a phenomenological way. We observed that greater temperatures lead nonlinear structure such as the polaron to become instable and disappear. Therefore, temperature is an important factor when it comes to describe the life time of these structures. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
MP2 study on decomposition of nitrous oxide on the Ga‐ZSM‐5
Authors: Solkan V. N. , Zhidomirov G. M. 
Published: July 2008

AbstractThe reaction mechanism for nitrous oxide decomposition has been studied on gallium site in Ga‐ZSM‐5 using the MP2/6‐31+G(d) method. The active centers were taken to be mononuclear [Ga]+, [GaO]+, and [GaO2]+ and the surrounding portion of the zeolite was represented by a 3T cluster, namely [AlSi2O4H8]−. The first elementary step of N2O decomposition involves the formation of [GaO]+ and the release of N2. The metal‐oxo species produced in this step then reacts with N2O again, to release N2 and form [GaO2]+. The calculated activation energies at MP2 level for N2O dissociation on Ga‐ZSM‐5 and GaO‐ZSM‐5 are 15.7 and 26.5 kcal/mol at 298 K, respectively. The third elementary step of N2O decomposition on GaO2‐ZSM‐5 involves the formation of [GaO3]+ and the release of N2. The calculated activation energy at MP2 level for N2O dissociation on GaO2‐ZSM‐5 is 43.7 kcal/mol. Four‐order perturbation theory (MP4//MP2) predicts that the activation barriers for nitrous oxide dissociation at 298 K on Ga‐ZSM‐5, GaO‐ZSM‐5, and GaO2‐ZSM‐5 are 13.9, 13.0, and 34.4 kcal/mol, respectively. The calculated energy for desorption of singlet O2 from the 3T−[Ga(O)3]+ cluster at MP2 level is 33.4 kcal/mol. When one takes into account the entropy gained on desorption of singlet O2, the contribution of entropy to the free energy of desorption is TΔS = 12.3 kcal/mol at 298 K. The calculated energy of the singlet oxygen desorption from 3T−[OGaO2]+ cluster ΔH (298 K) = +43.57 kcal/mol and ΔG(298 K) = 30.13 kcal/mol is significantly higher than the barriers of the singlet molecular oxygen desorption from 3T−[Ga(O)3]+ cluster. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
The quantum‐chemical study of small clusters of organic chromophores: Topological analysis and nonlinear optical properties
Authors: Balakina Marina Yu. , Fominykh Olga D. 
Published: July 2008

AbstractStructure and nonlinear optical properties of small clusters formed of organic chromophores through H‐bonding are studied by the example of dimer and trimer ofp‐nitroaniline (PNA). The analysis of the electron charge density pattern in the bonding region in terms of “Atoms in Molecules” approach is performed, and the values of electron charge density, Laplacian of electron density at critical points, etc. are determined. Topological analysis has given evidence of the existence of three‐center interaction of one amino group hydrogen with oxygens of nitro group of the neighboring PNA, resulting in two H‐bond formation. Solvent effect on the static (hyper)polarizability of the clusters is studied by the example of PNA dimer in acetone in the framework of conventional Polarizable Continuum Model as well as supermolecule and semicontinuum approaches. The essential increase of the cluster hyperpolarizability in comparison with that of a single chromophore is obtained. The account of specific interaction with the solvent molecule is shown to result in moderate or significant enhancement of β∥depending on the structure of the formed cluster. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Institutional history of an interactive science center: The founding and development of the Exploratorium
Authors: Ogawa Rodney T. , Loomis Molly , Crain Rhiannon 
Published: July 2008

AbstractThis study examines the historical conditions that fostered significant reform in science education. To understand these conditions, we employ a framework drawn from the new institutionalism in organization theory to study the founding and early development of the Exploratorium—a prominent science center that greatly impacted the field of science education. We examine how the Exploratorium employed institutional resources that were available in its environment to develop a new type of organization: an interactive science center. Our findings reveal that the Exploratorium was shaped by the state, which includes all levels of government; the mass media; and the professions, including science, education, and museums. In addition, we explore the pivotal role an individual, Frank Oppenheimer, played in leveraging the institutional environment in which an organization was developing. Our findings suggest that (a) reform in science education may be more profoundly advanced by the development of a new type of organization than by “tinkering” with an existing type of organization such as schools, and (b) that interactive science centers should exercise caution in navigating the changing seas of science education by maintaining their core mission and collaborating with new types of organizations that arise in response to the changing environment. © 2008 Wiley Periodicals, Inc. Sci Ed 93: 269–292, 2009
Disparities in defining disparities: Statistical conceptual frameworks
Authors: Duan Naihua , Meng Xiao‐Li , Lin Julia Y. , Chen Chih‐nan , Alegria Margarita 
Published: July 2008

AbstractMotivated by the need to meaningfully implement the Institute of Medicine's (IOM's) definition of health care disparity, this paper proposes statistical frameworks that lay out explicitly the needed causal assumptions for defining disparity measures. Our key emphasis is that a scientifically defensible disparity measure must take into account the direction of the causal relationship betweenallowable covariatesthat are not considered to be contributors to disparity andnon‐allowable covariatesthat are considered to be contributors to disparity, to avoid flawed disparity measures based on implausible populations that are not relevant for clinical or policy decisions. However, these causal relationships are usually unknown and undetectable from observed data. Consequently, we must make strong causal assumptions in order to proceed. Two frameworks are proposed in this paper, one is theconditional disparityframework under the assumption that allowable covariates impact non‐allowable covariates but notvice versa. The other is themarginal disparityframework under the assumption that non‐allowable covariates impact allowable ones but notvice versa. We establish theoretical conditions under which the two disparity measures are the same and present a theoretical example showing that the difference between the two disparity measures can be arbitrarily large. Using data from the Collaborative Psychiatric Epidemiology Survey, we also provide an example where the conditional disparity is misled by Simpson's paradox, whereas the marginal disparity approach handles it correctly. Copyright © 2008 John Wiley & Sons, Ltd.
Intention‐to‐treat analysis in cluster randomized trials with noncompliance
Authors: Jo Booil , Asparouhov Tihomir , Muthén Bengt O. 
Published: July 2008

AbstractIn cluster randomized trials (CRTs), individuals belonging to the same cluster are very likely to resemble one another, not only in terms of outcomes but also in terms of treatment compliance behavior. Although the impact of resemblance in outcomes is well acknowledged, little attention has been given to the possible impact of resemblance in compliance behavior. This study defines compliance intraclass correlation as the level of resemblance in compliance behavior among individuals within clusters. On the basis of Monte Carlo simulations, it is demonstrated how compliance intraclass correlation affects power to detect intention‐to‐treat (ITT) effect in the CRT setting. As a way of improving power to detect ITT effect in CRTs accompanied by noncompliance, this study employs an estimation method, where ITT effect estimates are obtained based on compliance‐type‐specific treatment effect estimates. A multilevel mixture analysis using an ML‐EM estimation method is used for this estimation. Copyright © 2008 John Wiley & Sons, Ltd.
Estimating local and global measures of association for bivariate interval censored data with a smooth estimate of the density
Authors: Bogaerts Kris , Lesaffre Emmanuel 
Published: July 2008

AbstractMeasures of association for bivariate interval censored data have not yet been studied extensively. Betensky and Finkelstein (Statist. Med. 1999; 18:3101–3109) proposed to calculate Kendall's coefficient of concordance using a multiple imputation technique, but their method becomes computer intensive for moderate to large data sets. We suggest a different approach consisting of two steps. Firstly, a bivariate smooth estimate of the density of log‐event times is determined. The smoothing technique is based on a mixture of Gaussian densities fixed on a grid with weights determined by a penalized likelihood approach. Secondly, given the smooth approximation several local and global measures of association can be estimated readily.The performance of our method is illustrated by an extensive simulation study and is applied to tooth emergence data of permanent teeth measured on 4468 children from the Signal‐Tandmobiel® study. Copyright © 2008 John Wiley & Sons, Ltd.
Occupational stress and cardiovascular disease
Authors: Byrne D.G. , Espnes Geir Arild 
Published: July 2008

AbstractLinks between occupational stress and cardiovascular risk have long been asserted. This paper reviews the evidence from the simple notion of occupational level and type as a risk through to the more theoretically sophisticated models of occupational stress as a determinant of cardiovascular risk and disease. It maps measures of occupational stress against the three related end points of coronary risk profiles, hypertension and clinical cardiovascular disease. Taken broadly, the evidence is supportive of postulated links. The persuasiveness of the evidence now points to intervention studies in the workplace as the next major focus of research. Copyright © 2008 John Wiley & Sons, Ltd.
A Randomized Trial of a Mental Health Consumer‐Managed Alternative to Civil Commitment for Acute Psychiatric Crisis
Authors: Greenfield Thomas K. , Stoneking Beth C. , Humphreys Keith , Sundby Evan , Bond Jason 
Published: July 2008

AbstractThis experiment compared the effectiveness of an unlocked, mental health consumer‐managed, crisis residential program (CRP) to a locked, inpatient psychiatric facility (LIPF) for adults civilly committed for severe psychiatric problems. Following screening and informed consent, participants (n = 393) were randomized to the CRP or the LIPF and interviewed at baseline and at 30‐day, 6‐month, and 1‐year post admission. Outcomes were costs, level of functioning, psychiatric symptoms, self‐esteem, enrichment, and service satisfaction. Treatment outcomes were compared using hierarchical linear models. Participants in the CRP experienced significantly greater improvement on interviewer‐rated and self‐reported psychopathology than did participants in the LIPF condition; service satisfaction was dramatically higher in the CRP condition. CRP‐style facilities are a viable alternative to psychiatric hospitalization for many individuals facing civil commitment.
Nystatin Interferes with the Effects of N‐Methyl‐N′‐nitro‐N‐nitrosoguanidine on Sphingolipid Metabolism in Human FL Cells
Authors: Liu Guangyi , Wang Weimin , Sun Gongping , Ma Xiaoqiong , Liu Ziyang , Yang Jun 
Published: July 2008

AbstractPreviously we have shown that an alkylating agent N‐methyl‐N′‐nitro‐N‐ nitrosoguanidine (MNNG) can induce receptor clustering and the activation of a downstream signal molecule NF‐κB, and that the receptor clustering is associated with changes in sphingolipids metabolism. On the other hand, the polyene antibiotic nystatin can block MNNG‐induced receptor clustering. In this study, using a lipidomic approach, we further evaluated whether nystatin influenced the effects of MNNG on sphingolipids metabolism. It was found that nystatin itself induced changes in the sphingolipids profile in human amnion FL cells to a certain extent, including an increase or decrease of some sphingolipid species. Interestingly, nystatin can block, at least partially, the changes of sphingolipids‐induced by MNNG. In addition, nystatin can also partially inhibit the activation of NF‐κB induced by MNNG. Neither MNNG nor nystatin affects the mRNA levels of serine palmitoyltransferase, acid sphingomyelinase (ASM), and sphingomyelin synthase, key enzymes in the sphingolipids biosynthesis pathway. However, MNNG can activate ASM and neutral sphingomyelinase, while nystatin preincubation inhibits the activation. Taken together, these data suggested that nystatin interferes with the effects of MNNG, and might elicit its function through altered sphingolipids metabolism.
Müller cell gliosis in retinal organ culture mimics gliotic alterations after ischemia in vivo
Authors: Kuhrt Heidrun , Wurm Antje , Karl Anett , Iandiev Ianors , Wiedemann Peter , Reichenbach Andreas , Bringmann Andreas , Pannicke Thomas 
Published: July 2008

AbstractA decrease in the expression of inwardly rectifying potassium (Kir) currents is a characteristic feature of retinal glial (Müller) cells in various retinopathies, e.g., after transient retinal ischemia. We used short‐term retinal organ cultures to investigate whether similar physiological alterations can be induced under in vitro conditions. During 4 days in vitro, Müller cells displayed a decrease in Kir currents and an increase in transient A‐type potassium currents which was similar to the alterations in membrane physiology during ischemia‐reperfusion in vivo. In addition, gliosis of Müller cells both in vivo and in organ cultures was associated with cellular hypertrophy and an alteration in osmotic swelling characteristics. Whereas Müller cells in control retinae did not swell under hypotonic stress, cells in postischemic retinae and in organ cultures swelled upon hypotonic challenge. Therefore, Müller cells in organ cultures can be used to investigate distinct aspects of ischemia‐induced Müller cell gliosis. Both the decrease in Kir currents and the alteration in osmotic swelling may reflect a dysfunction of Müller cells regarding the control of the ionic and osmotic homeostasis in the retina.
Frazzled cytoplasmic P‐motifs are differentially required for axon pathway formation in the Drosophila embryonic CNS
Authors: Dorsten Joy N. , VanBerkum Mark F.A. 
Published: July 2008

AbstractFrazzled is a Netrin‐dependent chemoattractive receptor required for axon pathway formation in the developing Drosophila embryonic CNS. The cytoplasmic domain is important and contains three conserved P‐motifs (P1, P2, and P3) thought to initiate intracellular signaling cascades and to crosstalk with other receptors during axon pathway formation. Here, we rescue homozygous frazzled embryos by pan‐neurally expressing a series of mutants lacking either the cytoplasmic domain or one of the conserved P‐motifs and assess the ability of these mutants to rescue frazzled defects in commissural, longitudinal and motor axon pathways. Surprisingly, while the cytoplasmic domain is required, removal of an individual P‐motif does not prevent gross formation of commissures. However, removal of P3 from Fra does prevent eagle‐expressing commissural axons from crossing the midline in the posterior commissure suggesting that some neurons have a stronger requirement for P3‐dependent signaling. Indeed, axons within the longitudinal connective as well as a small subset of motor neurons within the ISNb pathway also specifically require P3 to project to their targets correctly. In these latter axon projections, deleting the P1‐motif appears to de‐regulate the receptor's activity, actually increasing the frequency of motor neuron projection errors and inducing ectopic midline crossing errors. Collectively, these data demonstrate the critical nature of both the P1 and the P3‐motifs to Frazzled function in vivo during axon pathway formation.