bluuebunny/crossref_metadata_2025 huggingface dataset:
Macromol. Rapid Commun. 8/2008
Authors: Blake Robert B. , Pei Lei , Yang Li , Lee Michael V. , Conley Hiram J. , Davis Robert C. , Shirahata Naoto , Linford Matthew R.
Published: April 2008

Cover: During the past ten years, a number of researchers have described multistep methods for preparing thin polymer films on hydrogen‐terminated silicon. To the best of our knowledge we now show the first one‐step method (shown on the cover) for polymer thin film growth on this important substrate. This procedure involves the thermal decomposition of a radical initiator, which is believed to abstract hydrogen from the silicon surface. The resulting silicon radicals then appear to react with monomers in solution. Thicker polymer films are obtained by addition of a bifunctional monomer. Further details can be found in the article by R. B. Blake, L. Pei, L. Yang, M. V. Lee, H. J. Conley, R. C. Davis, N. Shirahata, and M. R. Linford* on page 638.
Psychometric properties of the Retrospective Self Report of Inhibition (RSRI) in a representative German sample
Authors: Rohrbacher Heike , Hoyer Jürgen , Beesdo Katja , Höfler Michael , Bittner Antje , Lieb Roselind , Wittchen Hans‐Ulrich
Published: April 2008

The present study examined the internal consistency, factorial structure, and construct validity of the German version of the Retrospective Self Report of Inhibition (RSRI), a questionnaire measure of behavioral inhibition. The research was based on data from a German prospective‐longitudinal community study of 3021 adolescents and young adults (aged 14–24 years at baseline). Diagnostic assessment was based on the DSM‐IV/M‐CIDI and general psychopathological distress was assessed with SCL‐90‐R. Results of confirmatory factor analysis indicated adequate fit of the two‐factor model, suggested by the authors of the original version. Indices of internal consistency of the RSRI and its subscales ‘social/school’ and ‘fear/illness’ were shown to be sufficient for the total sample and even higher in subgroups of subjects with certain DSM‐IV diagnoses. Associations with variables such as mental distress, parental psychopathology, and DSM‐IV disorders were in line with theoretical assumptions and confirm different aspects of the validity (convergent, concurrent, predictive) of the instrument. The psychometric properties of the German RSRI were found to be comparable to those of the English version. The applicability of this questionnaire in German‐speaking countries is therefore recommended for adolescents and young adults. Copyright © 2008 John Wiley & Sons, Ltd.
A posteriori estimates for the Stokes eigenvalue problem
Authors: Lovadina Carlo , Lyly Mikko , Stenberg Rolf
Published: April 2008

We consider the Stokes eigenvalue problem. For the eigenvalues we derive both upper and lower a‐posteriori error bounds. The estimates are verified by numerical computations. © 2008 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2009
Renewable resource‐based poly (m‐phenylenevinylene)s and their statistical copolymers: Synthesis, characterization, and probing of molecular aggregation and Forster energy transfer processes
Authors: Cyriac Anish , Amrutha S. R. , Jayakannan M.
Published: April 2008

We report a novel poly (m‐phenylenevinylene)s and their copolymers based on renewable resource starting material 3‐pentadecylphenol to trace the Forster energy transfer process and molecular aggregation in the π‐conjugated polymers. The new bisylide monomer was polymerized with bisaldehyde (or benzaldehyde) under Wittig‐Horner reaction conditions to prepare poly [(4‐methoxy‐6‐pentadecyl‐1, 3‐phenylenevinylene)‐alt‐(1, 3‐phenylenevinylene)] (m‐PPV) and its para‐counterpart poly [(4‐methoxy‐6‐pentadecyl‐1, 3‐phenylenevinylene)‐alt‐(1, 4‐phenylenevinylene)] (p‐PPV) and oligo‐phenylenevinylene model compound 4‐methoxy‐6‐pentadecyl‐1, 3‐distyrylbenzene (OPV). A series of with m‐ or p‐conjugated segments were also prepared by varying the m‐ and p‐content from 0 to 100% in the feed. The selective excitation of m‐conjugated segments in the copolymer by 310 nm light showed emission properties of pure p‐conjugated segments indicating the efficient Forster energy transfer process in segmented copolymers. Both solution quantum yields and the emission intensities increase up to 75% of para‐content in the copolymers. In the solid state, the increase in the p‐incorporation in the copolymer decreases the photoluminescent intensity almost by four times as compared to that of pure meta‐substituted PPV. The excitation spectra of the polymers confirmed a new peak at 400 nm corresponding to the aggregated polymer chains in the film, which is absent in the solution. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3241–3256, 2008
Synthesis of star poly(1,3‐cyclohexadiene): Grafting reaction of poly(1,3‐cyclohexadienyl)lithium onto C60
Authors: Natori Itaru , Natori Shizue
Published: April 2008

The grafting reaction of poly(1,3‐cyclohexadienyl)lithium onto fullerene‐C60 (C60) was strongly affected by the nucleophilicity of poly(1,3‐cyclohexadiene) (PCHD) carbanions and the polymer chain microstructure, and progressed via step‐by‐step reactions. A star‐shaped PCHD, having a maximum of four arms, was obtained from poly(1,3‐cyclohexadienyl)lithium composed of all 1,4‐cyclohexadiene (1,4‐CHD) units. The rate of the grafting reaction was accelerated by the addition of amine. The grafting density of PCHD arms onto C60 decreased with an increase in the molar ratio of 1,2‐cyclohexadiene (1,2‐CHD) units. The electron‐transfer reaction from PCHD carbanions to C60 did not occur in either a nonpolar solvent or a polar solvent. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3282–3293, 2008.
Morphological investigation on melt crystallized polylactide homo‐ and stereocopolymers by enzymatic degradation with proteinase K
Authors: He Yong , Wu Tong , Wei Jia , Fan Zhongyong , Li Suming
Published: April 2008

Polylactide (PLA) homo‐ and stereocopolymers containing 100, 98, 96, 94, and 92% L‐lactyl units, respectively, were synthesized by ring opening polymerization of L‐lactide and DL‐Lactide, using zinc lactate as catalyst. Differential scanning calorimetric analysis measurements show that incorporation of D‐lactyl units leads to decrease of the crystallization rate of the copolymers. However, the crystallization mechanism and the amount of crystallizable fraction are not affected. The enzymatic degradation was performed at 37 °C in a pH 8.6 Tris buffer containing proteinase K. Two distinct morphologies were obtained by melt crystallization for PLA films with ca. 80 μm of thickness. It is confirmed that proteinase K can degrade both the free and confined amorphous regions. Lamella stacks in spherulites retain their orientation during enzymatic degradation. PLA crystal morphologies are affected by the content of D‐lactyl units. Factors such as the nucleus location and the D‐lactyl units' exclusion as amorphous fraction were considered to elucidate the observed PLA spherulite morphologies. Infrared spectroscopy and mass loss measurements were also combined to better understand the degradation behaviors. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 959–970, 2008
Physical gelation of water‐borne thermosetting resins by percolation theory—Urea‐formaldehyde, melamine‐urea‐formaldehyde, and melamine‐formaldehyde resins
Authors: Celzard A. , Pizzi A. , Fierro V.
Published: April 2008

Percolation and effective‐medium theories are applied for calculating the connectivity threshold of colloid particles of given shapes, observed during the physical gelation, distinguished from chemical gelation, of aminoplastic resins. The rigidity threshold, being the critical solid fraction at which a rigid network is first formed, was also calculated. For that purpose, it was assumed that the central forces that act between the colloidal particles and aggregates were not alone, thus corresponding to the case of physical gelation. It was shown that the observed change of morphology exhibited by such particles and aggregates as a function of time, from elongated to spherical, significantly delays the gel point. Consequently, the latter occurs only after a rather high fraction of solid phase (typically from 30 to 60%) is formed. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 971–978, 2008
Epidermal growth factor receptor (EGFR) expression in prostatic adenocarcinoma after hormonal therapy: A fluorescence in situ hybridization and immunohistochemical analysis
Authors: Marks Rebecca A. , Zhang Shaobo , Montironi Rodolfo , McCarthy Ryan P. , MacLennan Gregory T. , Lopez‐Beltran Antonio , Jiang Zhong , Zhou Honghong , Zheng Suqin , Davidson Darrell D. , Baldridge Lee Ann , Cheng Liang
Published: April 2008

BACKGROUND

The progression of normal prostatic epithelium to androgen‐dependent cancer and, eventually, hormone‐refractory prostate cancer is a complex process involving many different growth regulatory signals. Activation of epidermal growth factor receptor (EGFR) has been implicated in prostate cancer cell growth.

METHODS

This study was undertaken to investigate both amplification of EGFR gene by fluorescence in situ hybridization (FISH) and over‐expression of EGFR by immunohistochemical staining in prostate tissue from 71 patients treated by hormonal therapy.

Results

EGFR gene amplification was present in 1 of 71 tumors, and polysomy of chromosome 7 was present in 24 of 71 tumors. Immunohistochemically, EGFR expression was demonstrable in 57 of 71 tumors. Membranous immunostaining for EGFR was observed in >75% of tumor cells in 11% of cases, in 51–75% of tumor cells in 20% of cases, in 26–50% of tumor cells in 21% of cases, in 11–25% of tumor cells in 21% of cases, and in 1–10% of tumor cells in 7% of cases. No immunostaining for EGFR was seen in 20% of cases. There was no correlation between EGFR protein expression and gene amplification. There was also no correlation between EGFR expression and clinicopathological characteristics or clinical outcome.

CONCLUSIONS

We found that EGFR gene expression was detectable in 35% of this large series of hormone‐treated prostate cancer, and that EGFR protein is frequently expressed in tissue from these patients. EGFR over‐expression may serve as a reasonable target for therapeutic intervention in this otherwise difficult to treat subset of prostate cancer. Prostate 68:919–923, 2008. © 2008 Wiley‐Liss, Inc.
Weak self‐association of human growth hormone investigated by nitrogen‐15 NMR relaxation
Authors: Jensen Malene Ringkjøbing , Kristensen Søren M. , Keeler Camille , Christensen Hans E. M. , Hodsdon Michael E. , Led Jens J.
Published: April 2008

The self‐association of human growth hormone (hGH) was investigated using 15N NMR relaxation. The investigation relies on the 15N R1 and R2 relaxation rates and the heteronuclear {1H}‐15N NOEs of the backbone amide groups at multiple protein concentrations. It is shown that the rotational correlation time of hGH in solution depends strongly on its concentration, indicating a significant degree of self‐association. The self‐association is reversible and the monomers in the aggregates are noncovalently linked. Extrapolation of the relaxation data to zero concentration predicts a correlation time of 13.4 ns and a rotational diffusion anisotropy of 1.26 for monomeric hGH, in agreement with the rotational diffusion properties estimated by hydrodynamic calculations. Moreover, the extrapolation allows characterization of the backbone dynamics of monomeric hGH without interference from self‐association phenomena, and it is found that hGH is considerably more flexible than originally thought. A concerted least‐squares analysis of the 15N relaxations and their concentration dependence reveals that the self‐association goes beyond a simple monomer‐dimer equilibrium, and that tetramers or other multimeric states co‐exist in fast exchange with the monomeric and dimeric hGH at sub‐millimolar concentrations. Small changes in the 1H and 15N amide chemical shifts suggest that a region around the C‐terminus is involved in the oligomer formation. Proteins 2008. © 2008 Wiley‐Liss, Inc.
Quantum transport through nanowires: Ab initio studies using plane waves and supercells
Authors: Oetzel Björn , Preuss Martin , Ortmann Frank , Hannewald Karsten , Bechstedt Friedhelm
Published: April 2008

We present a numerical scheme for an ab initio implementation of the Landauer‐Büttiker theory for quantum transport by means of supercells and plane‐wave basis sets. The suggested method works entirely in k‐space which allows to circumvent the complicated projections onto tight‐binding Hamiltonians necessary in the more common real‐space approaches to quantum transport. As a first example for the usefulness of the method, we present DFT calculations of transmission functions for various one‐dimensional Au nanowires. The results are discussed with respect to future extensions to metal‐molecule‐metal nanojunctions. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
White X‐ray microdiffraction analysis of defects, strain and tilts in a free standing GaN film
Authors: Barabash R. I. , Ice G. E. , Haskell B. A. , Nakamura Shuji , Speck J. S. , Liu W.
Published: April 2008

A novel white‐beam microdiffraction analysis of defects, strains and tilts in a free standing m ‐plane GaN film grown via hydride vapor phase epitaxy is presented. It is shown that misfit dislocations are grouped within cell boundaries creating local lattice rotations (tilts) between the growing cells. Distribution of lattice rotations in the film is not homogeneous. Regions of large rotations are separated by low rotations regions. The dominating rotation axis is parallel [11$ \bar 2 $0] direction. High in plane shear stress component is observed along [0001]. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Atom probe reveals the structure of InxGa1–xN based quantum wells in three dimensions
Authors: Galtrey M. J. , Oliver R. A. , Kappers M. J. , McAleese C. , Zhu D. , Humphreys C. J. , Clifton P. H. , Larsen D. , Cerezo A.
Published: April 2008

The three‐dimensional atom probe has been used to characterize InxGa1–xN based multiple quantum well structures emitting from the green to the ultra‐violet with sub‐nanometre resolution over a 100 nm field of view. The results show gross discontinuities and compositional variations within the UV‐emitting quantum well layers on a 20–100 nm length scale. We propose that these may contribute to the high efficiency of this structure. In addition, the analysis shows the presence of indium in the barrier layers of all the samples, whether or not there was an indium precursor present during barrier growth. The distribution of indium within the blue‐ and green‐emitting InxGa1–xN quantum wells is also analyzed, and we find no evidence that InxGa1–xN with a range of compositions is not a random alloy, and so rule out indium clustering as the cause of the reported carrier localization in these structures. The upper interface of each quantum well layer is shown to be rougher and more diffuse than the lower, and the existence of monolayer steps in the interfaces that could effectively localize carriers at room temperature is revealed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ga self‐interstitials in GaN investigated by ab‐initio calculations of the electronic g ‐tensor
Authors: Gerstmann U. , Seitsonen A. P. , Mauri F.
Published: April 2008

In GaN, an exceptionally important role is played by Ga‐interstitials being mobile at room temperature. Despite rather large formation energy, they have been observed in irradiated wurtzite‐GaN: at least two similar, but clearly distict ODEPR‐signals L5 and L6/L6* have been identified (via exceptionally large, nearly isotropic hyperfine splittings of about 4 GHz) as interstitial $ {\rm Ga}^{2+}_{\rm i} $ in two diffent lattice configurations. However, judging from experimental data and total energy calculations alone, the exact microscopic configuration remains unclear. In this theoretical work, the situation is elucidated by ab‐initio calculating the complete set of EPR parameters, hyperfine splittings as well as g ‐tensors, for the stable structural configurations of the Ga‐interstitial using a gauge‐including projector augmented plane wave (GI‐PAW) approach. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Space charged region in GaN and InN nanocolumns investigated by atomic force microscopy
Authors: Niebelschütz M. , Cimalla V. , Ambacher O. , Machleidt T. , Franke K.‐H. , Ristic J. , Grandal J. , Sánchez‐García M. A. , Calleja E.
Published: April 2008

High quality InN and GaN nanocolumns of different length and diameter grown by molecular beam epitaxy (MBE) were electrically characterized directly and non‐destructively by Atomic Force Microscopy (AFM) as a function of the column diameter. The “exact” column diameter was determined from AFM images by Blind Tip Estimation (BTE) and subsequent image reconstruction in order to avoid artefacts due to the finite AFM tip radius. In GaN, the conductivity rises up to a “critical” diameter due to a depletion region at the surface of the nanocolumns and remains constant above. In contrast, the electron accumulation at the surface causes decreasing conductivity in InN nanocolumns with increasing diameter. Thus, the nanocolumn surface acts as the preferential conduction path. These facts prove that there is electron accumulation in as‐grown non‐polar InN surfaces, according to calculations of the Fermi level pinning in InN. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Defect‐related recombination in InGaN‐lasers
Authors: Schillgalies M. , Laubsch A. , Lutgen St. , Avramescu A. , Brüderl G. , Queren D. , Strauss U.
Published: April 2008

We have studied the influence of impurities in InGaN lasers. A magnesium background doping in InGaN quantum wells increases non‐radiative recombination significantly. Consequently, internal quantum efficiency decreases causing a large drop in laser performance. Electroluminescence measurements over a wide current and temperature range were used to study magnesium‐related radiative and non‐radiative recombination processes. Defect‐related processes are thermally activated. Quenching of EL‐intensity increases with magnesium concentration and is attributed to increased non‐radiative recombination as a result of thermal release of bound holes. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
InN/In2O3 heterostructures
Authors: Wang Ch. Y. , Cimalla V. , Lebedev V. , Kups Th. , Ecke G. , Hauguth S. , Ambacher O. , Lozano J. G. , Morales F. M. , González D.
Published: April 2008

Cubic (c‐) InN is predicted to possess superior electronic properties for device applications, while c‐In2O3 is an excellent candidate as gate material for InN based high‐frequency field effect transistors. In this paper, the epitaxial growth of the InN/In2O3 and In2O3/InN heterosystems was investigated. High‐quality c‐InN (001) was deposited on (001) In2O3 tem‐ plate, while single crystalline c‐In2O3 was epitaxially grown on hexagonal InN (0001). The epitaxial relationship of the heterosystems was determined. Phenomenological models of the nucleation and of an atomic arrangement at the interface are proposed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High temperature behaviour of GaN HEMT devices on Si(111) and sapphire substrates
Authors: Cuerdo R. , Calle F. , Braña A. F. , Cordier Y. , Azize M. , Baron N. , Chenot S. , Muñoz E.
Published: April 2008

A study of the high temperature DC performance of nitride high electron mobility transistors (HEMTs) on Si(111) and sapphire substrates with different gate lengths is reported. All single gate transistors decrease their drain current (ID) and transconductance (gm) from room temperature (RT) up to 350 °C, mainly due to the electron mobility reduction by optical phonon scattering. At RT, HEMTs on Si(111) present higher ID and gm than transistors on sapphire, probably related to their lower self‐heating. As devices are heated, these differences tend to disappear, indicating that the substrate thermal conductivity becomes less important. Compact devices have low relative reduction in ID and gm values with temperature, since shorter gate lengths lead to higher fields under the gate and lower temperature dependence of the drift velocity. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fabrication and stress relief modelling of GaN based MEMS test structures grown by MBE on Si(111)
Authors: Sillero E. , López‐Romero D. , Bengoechea A. , Sánchez‐García M. A. , Calle F.
Published: April 2008

The fabrication of III‐N MEMS test structures, such as cantilevers, beams and stress‐pointers, and the modelling of their deformation due to residual stress relief, is presented. GaN and AlGaN/GaN structures were fabricated, either with one end and both ends clamped to the Si substrate (asymmetrical and symmetrical mechanical boundary conditions, respectively). The residual stress in the III‐N layer was measured by photoluminescence and X‐ray diffraction, and the stress relief induced deformation was analysed by a finite element method model. The deformations of the MEMS structures were used to calculate both the residual strains and the Young's modulus of the material. One‐end‐clamped structures suffer from large deformations due to the uneven stress relaxation. During micromachining, the relaxation induces large upward buckling, as measured for fabricated devices and fitted by the FEM model. Two‐end‐clamped structures were also studied using different topologies and under‐etching lengths of the clamped region. It is concluded that the deformation of such structures may be reduced with symmetrical mechanical boundary conditions and a small under‐etched clamping region compared to the device dimensions. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Theoretical study of O2 adsorption and CO2 formation in bimetallic dimer clusters Au‐M
Authors: Pacheco‐Ortín Sandy Maria , Agacino‐Valdés Esther , de la Mora Pablo
Published: April 2008

Cation, anion, and neutral states in Au‐M dimer clusters have been calculated as a way to study in a small model, the Au‐sites, and M‐sites in a supported nanoparticle (NP). These charged states can be formed during a charge transfer process between certain atoms of the NP with the atoms of the support or simply with cationic or anionic defects. These results can be important to evaluate in a preliminary way, the relation between the activity of the Au‐sites and M‐sites because of its charge and the effectiveness of the adsorption of O2, and the subsequent interaction between adsorbed O2 and CO through a Langmuir‐Rideal unimolecular mechanism. For the O2 adsorption over Au active site, the Au‐Ir, Au‐Au, Au‐Ag, Au‐Pd, and Au‐Cu dimers yielded negative binding energies in all the charge states considered (anion, cation, and neutral); when M active site was considered, Au‐Cu and Au‐Ag dimers also gave negative values of binding energies in all the charged states. Furthermore, there was observed that electron rich Au‐sites are essential in the O2 adsorption. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
A group of 3D graphical representation of DNA sequences based on dual nucleotides
Authors: Cao Zhi , Liao Bo , Li Renfa
Published: April 2008

Based on chemical properties of the neighboring dual nucleotides, we reduce a DNA sequence into four 3D graphical representations. Associating with the eigenvalues of the introduced covariance matrix and the introduced measure of similarity, we introduce an approach to make similarity analysis of DNA sequence. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Interfacial properties of thermally oxidized Ta2Si on Si
Authors: Pérez‐Tomás A. , Jennings M. R. , Mawby P. A. , Millán J. , Godignon P. , Montserrat J. , Rossinyol E. , Vennegues P. , Stoemenos J.
Published: April 2008

Many refractory metal silicides have received great attention due to their potential for innovative developments in the silicon‐based microelectronic industry. However, tantalum silicide, Ta2Si, has remained practically unnoticed since its successful application in silicon carbide technology as a simple route for a high‐k dielectric formation. The thermal oxidation of Ta2Si produces high‐k dielectric layers, (OTa2Si)‐based on a combination of Ta2O5 and SiO2. In this work, we investigate the interfacial properties of thermally oxidized (850–1050 °C) Ta2Si on commercial silicon substrates. The implications of diffusion processes in the dielectric properties of an oxidized layer are analyzed. In particular, we observe migration of tantalum pentoxide nanocrystals into the substrate with increasing oxidation temperature. An estimation of the insulator charge and interfacial OTa2Si/Si trap density is also presented. Copyright © 2008 John Wiley & Sons, Ltd.
Learning how to restructure: absorptive capacity and improvisational views of restructuring actions and performance
Authors: Bergh Donald D. , Lim Elizabeth Ngah‐Kiing
Published: April 2008

This paper examines the role of learning in corporate restructuring. Drawing from two viewpoints of organizational learning, absorptive capacity and organizational improvisation, we examine whether experience with corporate restructuring modes (sell‐offs, spin‐offs) influences subsequent restructuring and financial performance. Consistent with an absorptive capacity view, cumulative and repetitive experience with sell‐offs was related to the adoption of an ensuing sell‐off and to higher performance. Conversely, and consistent with an organizational improvisation view, short‐term and contemporaneous experience with spin‐offs was related to the subsequent use of spin‐offs and to increases in financial performance. The findings contribute to a dynamic explanation of corporate restructuring and its influence on financial performance, illustrate differences between learning in a repetitive situation and learning when repetition is rare, and indicate when absorptive capacity and organizational improvisational views are most profitable. Overall, these findings show that different kinds of restructuring experiences were associated with different modes of restructuring and performance records. Considered collectively, the organizational learning perspective offers insights into why some corporate restructuring strategies appear as intentional and deliberate actions while others resemble more spontaneous and simultaneous responses. Copyright © 2008 John Wiley & Sons, Ltd.
Environmental risk management and the cost of capital
Authors: Sharfman Mark P. , Fernando Chitru S.
Published: April 2008

Our study of 267 U.S. firms shows that improved environmental risk management is associated with a lower cost of capital. Our findings provide an alternative perspective on the environmental‐economic performance relationship, which has been dominated by the view that improvements in economic performance stem from better resource utilization. Firms also benefit from improved environmental risk management through a reduction in their cost of equity capital, a shift from equity to debt financing, and higher tax benefits associated with the ability to add debt. These findings help build better theory regarding the outcomes of strategic improvements in environmental risk management. Copyright © 2008 John Wiley & Sons, Ltd.
Influence of Gas Flow Ratio in PE‐CVD Process on Mechanical Properties of Silicon Nitride Film
Authors: Oh Hyun‐Jin , Isono Yoshitada , Namazu Takahiro , Saito Yoshihiro , Yamaguchi Akira
Published: April 2008

This paper investigates the influence of gas flow ratio in the preparation of submicron‐thick silicon nitride (SiNx) films on their elastic properties. SiNxfilms with a thickness ranging from 0.14 to 0.69 µm were deposited by plasma‐enhanced chemical vapor deposition (PE‐CVD) onto 10‐µm‐thick single‐crystal silicon (SCS) specimens by changing the gas flow ratio of monosilane (SiH4) to ammonia (NH3) to nitrogen (N2). A uniaxial tensile tester operated under an atomic force microscope (AFM) characterized the Young's modulus of SiNxfilms and the fracture strength of SiNx/SCS laminated specimens. The Young's modulus of SiNxfilms ranged from 99.5 to 144.3 GPa, which increased with the gas flow ratio but was independent of the film thickness. Nano‐indentation tests were also carried out to examine the Poisson's ratio of SiNxfilms in addition to the tensile tests. The Poisson's ratio was found to be 0.19 to 0.27, on average. Auger spectroscopy revealed that an increase of the atomic content ratio of nitrogen (N) to silicon (Si) in SiNxfilms yielded higher elastic constants of the films. © 2008 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Contrast Improvement Method for Monochrome Images Based on the Ratio of Local Variances of Gray levels
Authors: Saitoh Fumihiko
Published: April 2008

When the contrast of a captured image is not good, a method for contrast improvement may be useful. Especially, liner transform (LT) of gray levels and the histogram equalization (HE) method are well known as general methods. However, an effective contrast improvement does not always work, or an unnatural output is often generated by these methods. This paper proposes a method for contrast improvement to generate an image with medium contrast between those obtained by LT and HE. An input image is separated into an object area and a background area by every pixel. The variance of gray levels in the local area is used for measuring the local contrast. The ratio of the variances of gray levels in these areas is evaluated to determine the relative weights of LT and HE. The experimental results show that output images with higher contrast than that by LT and with less saturation of brightness and less noise than those by HE were generated by the proposed method. Copyright © 2008 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Running Test of Contactwire‐less Tramcar Using Lithium Ion Battery
Authors: Ozawa Hironori , Ogihara Takashi
Published: April 2008

The basic specification of lithium ion battery‐type tramcar was established using DC600V‐type tramcar with a weight of 40 t. Forty five kilo Watt hour of manganese‐type lithium ion battery was used. The running test was carried out for the first time in Japan in the business line. The relation between running time and voltage, current and integrating watt was investigated in detail. The tramcar was run when the lithium ion battery module was discharged between 660 and 480 V. On one charge, the tramcar could run for about 25 km. The mileage of contactwire‐less tramcar improved two times that of tramcar. The running performance of contactwire‐less tramcar was equivalent to the tramcar. Copyright © 2008 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Rhombencephalosynapsis: prenatal imaging and autopsy findings
Authors: McAuliffe F. , Chitayat D. , Halliday W. , Keating S. , Shah V. , Fink M. , Nevo O. , Ryan G. , Shannon P. , Blaser S.
Published: April 2008

Objectives

Rhombencephalosynapsis is a rare, but increasingly recognized, brain malformation characterized by congenital fusion of the cerebellar hemispheres and absence of the vermis. Rhombencephalosynapsis is associated with significant developmental delay, seizures and involuntary head movements. We report four cases, with correlation of prenatal and postnatal imaging and autopsy findings.

Methods

Over a 2‐year period, four cases of rhombencephalosynapsis were diagnosed in the perinatal period, three in one center and one in another center. The clinical cases were reviewed, and correlation was made between the prenatal and postnatal imaging and autopsy findings where available.

Results

All cases presented initially with ventriculomegaly on prenatal ultrasound examination. Subsequent magnetic resonance imaging (MRI) established the diagnosis in two cases and postnatal MRI established the diagnosis in a further two cases. Autopsy was available and confirmed the diagnosis in two cases. In one case the pregnancy was terminated, two infants died in the neonatal period and one died in infancy.

Conclusions

The cases in this perinatal series of rhombencephalosynapsis showed a very poor prognosis. The presence of ventriculomegaly on prenatal ultrasound imaging should alert the physician to consider rhombencephalosynapsis in the differential diagnosis. MRI appears to be the imaging modality of choice in establishing the diagnosis. Copyright © 2008 ISUOG. Published by John Wiley & Sons, Ltd.
Acute Care Surgery: A New Training and Practice Model in the United States
Authors: Hoyt David B. , Kim Hubert D. , Barrios Cristobal
Published: April 2008

The specialty of trauma is at a crossroads. Choosing a career in trauma is associated with concerns related to lifestyle issues and maintenance of adequate operative experience. Trauma and critical care surgeons in the U.S. have reexamined their role based on these concerns and the realization that surgeon resources for the injured patient are in jeopardy. After much work over the past five years, a model of “Acute Care Surgery” has emerged and a training curriculum has been proposed. This article reviews the evolution of a new specialty and identifies some of the challenges and opportunities associated with the implementation of this model.
Surgeons Underestimate Their Patients’ Desire for Preoperative Information
Authors: Keulers B. J. , Scheltinga M. R. M. , Houterman S. , Van Der Wilt G. J. , Spauwen P. H. M.
Published: April 2008

Background

Provision of adequate patient information may contribute to a “satisfying” surgical treatment. The patient’s views on successful transfer of information concerning operative characteristics may not be in concert with the surgeon’s. The aim of the present study was to determine opinions of both surgeons and patients about issues of surgical information.

Methods

A group of surgeons (n = 24) and surgical patients (n = 125) responded to a questionnaire that included 80 topics involving domains of information on disease, physical examination, preoperative period, anesthesia, operation, postoperative period, self care, and general hospital issues. Both groups were asked for their opinion on what they considered important and useful preoperative information for patients. Questions were scored with a visual analog scale. The reliability of the questionnaire was calculated with Cronbach’s alpha. Differences in opinions between surgeons and patients were analyzed with Student’s t‐test.

Results

The Cronbach’s alpha of the questionnaire was high (0.91), indicating its high reliability. Patients scored significantly higher (p < 0.001) in most domains, including preoperative period, anaesthesia, operation, postoperative period, self care, and general hospital information. Women demonstrated a significantly higher need for information than men did. These findings were independent of patient age or complexity of operation. In contrast, surgeons thought that their patients desired more extensive information on cause, effect, and prognosis of the disease itself (p < 0.001).

Conclusion

Surgeons generally underestimate their patients’ desire for receiving extensive information prior to a surgical procedure of any complexity. Surgeons should develop strategies to bridge this informational mismatch.
Cytotoxicity of the isoflavone genistein in NIH 3T3 cells
Authors: Rucinska Agata , Roszczyk Magda , Gabryelak Teresa
Published: April 2008

Genistein is one of the naturally occurring isoflavones present in plants such as soybeans and is commonly found in a variety of human foods. A number of studies indicated that this class of compounds exerts anticancerogenic and antimutagenic effects in various in vitro systems and in vivo animal models. We studied the effects of genistein on NIH 3T3 cells in in vitro models. The isoflavone genistein has been identified as having antiproliferative and apoptotic effects on various malignant cell types derived from solid tumors. Therefore, the cytotoxic and apoptotic properties of this compound were studied by MTT assay and Hoechst 33258/propidium iodide staining technique. The morphological changes of cells were examined in inverted fluorescent microscope. The oxidation of protein thiol groups and thiobarbituric‐acid‐reactive species (TBARS) was also determined. The cells were exposed to different concentrations of genistein (0–90 μM) after 24 h of incubation. The results revealed that genistein in concentrations higher than 20 μM significantly reduced cell viability, caused cell morphological changes and induced apoptotic and necrotic cell death. Oxidative modification of protein increased in the cells exposed to genistein in a dose‐ and time‐dependent manner. In conclusion, our preliminary in vitro studies demonstrate the damaging effects of genistein on the mouse embryonic fibroblast cell line.
Mitochondrial DNA from colorectal cancer cells promotes the malignant phenotype of NIH3T3 cells
Authors: Li Yan , Weibing Song , Liu Hong , Hongli Ji , Zhuosheng Lai , Yadong Wang , Bing Xiao , Daiming Fan
Published: April 2008

We investigated the potential role of mitochondrial DNA (mtDNA) in colorectal carcinogenesis by constructing a eukaryotic expression vector of the mitochondrial D‐loop gene from colorectal cancer cell SW480 and transfected NIH3T3 cells. The NIH3T3/SW480 cells exhibited a significantly increased growth rate and colony formation rate, and also had a decreased apoptotic rate. Polyploidy and aberrant chromosomes were detected in the NIH3T3/SW480 cells by chromosome karyotype analysis. Our results suggested that mtDNA from colorectal cancer cells promotes the malignant phenotype of NIH3T3 cells. Further study of the biological functions of NIH3T3/SW480 cells might be helpful in understanding the role of mtDNA in colorectal carcinogenesis.
Inactivation of epoxide hydrolase by catalysis‐induced formation of isoaspartate
Authors: van Loo Bert , Permentier Hjalmar P. , Kingma Jaap , Baldascini Helen , Janssen Dick B.
Published: April 2008

Epoxide hydrolases catalyze hydrolytic epoxide ring‐opening, most often via formation of a covalent hydroxyalkyl‐enzyme intermediate. A mutant of Agrobacterium radiobacter epoxide hydrolase, in which the phenylalanine residue that flanks the invariant catalytic aspartate nucleophile is replaced by a threonine, exhibited inactivation during conversion when the (R)‐enantiomer of p‐nitrostyrene epoxide was used as substrate. HPLC analysis of tryptic fragments of the epoxide hydrolase, followed by MALDI‐TOF and TOF/TOF analysis, indicated that inactivation was due to conversion of the nucleophilic aspartate into isoaspartate, which represents a novel mechanism of catalysis‐induced autoinactivation. Inactivation occurred at a lower rate with the (S)‐enantiomer of p‐nitrostyrene epoxide, indicating that it is related to the structure of the covalent hydroxyalkyl‐enzyme intermediate.
TEXTILES AND THE MAYA ARCHAEOLOGICAL RECORD
Authors: Chase Arlen F. , Chase Diane Z. , Zorn Elayne , Teeter Wendy
Published: April 2008

Textiles formed a major part of any ancient Mesoamerican economy. Based on ethnohistory and iconography, the Maya were great producers of cloth for both internal and external use. However, the archaeological identification of textile production is difficult in any tropical area because of issues of preservation. This paper examines the evidence for the production and distribution of cloth that is found in the pre-Columbian Maya area and then focuses on archaeological data relative to textiles from the ancient Maya city of Caracol, Belize. Archaeology at Caracol has been carried out annually from 1985 to the present and has resulted in the collection of data that permits insight into the economic production and social distribution of cloth at the site. This is accomplished through examining the contexts and distributions of spindle whorls, bone needles, bone pins and hairpins, bone awls, and limestone bars. All of these artifacts can be related to weaving, netting, or cloth in some way. Importantly, perforated ceramic disks are not included in this grouping because of contextual information from the archaeological record that these artifacts likely functioned as backings for ear assemblages. Spindle whorls are the artifacts most clearly associated with textile production and 57 of these have been recovered at Caracol, 38 of them in 20 different burials. Several of these interments are of high-status women placed in the most important architectural constructions at the site. The contextual placement of these burials stresses not only the link between women and weaving, but also the high status associated with such an activity, thus signaling the importance of cloth and spinning in ancient Maya society. The prevalence of female interments in the major ritual buildings at Caracol also reflects the importance of women to Maya social structure during the Classic period (a.d.250–900), pointing to difficulties in hieroglyphically based interpretations of ancient Maya social organization and suggesting that the traditional focus on males in the sociopolitical organization of the Classic Maya is incorrect.
FIBER TECHNOLOGY AND WEAVING IN FORMATIVE-PERIOD GULF COAST CULTURES
Authors: Follensbee Billie J. A.
Published: April 2008

While research has revealed the important role that textiles have played in Mesoamerica from the Classic period through contemporary cultures, few studies have explored the importance of textiles in earlier Mesoamerican cultures. Scant preservation thwarts research on Formative-period cultures such as the Gulf Coast Olmec, for which only a few fragments of cordage and woven mats have yet been recovered. However, considerable additional evidence of textiles is available through other material culture, such as the rich pictorial record of fibers and cloth shown in Olmec sculpture. Further evidence exists in textile-related ceramic artifacts recovered from Gulf Coast sites, and still more evidence can be found through the reevaluation of greenstone artifacts recovered from Gulf Coast sites and “heirloom caches” of Formative-period objects. Careful analysis of the form and iconography of certain types of provenienced greenstone artifacts reveals that these may have served as elite textile-making tools; replication studies confirms their functionality as implements for spinning, weaving, and making cordage. All together, this study suggests that the Gulf Coast Olmec already held not only textiles but textile making in high esteem during the Formative period, foreshadowing the great significance of textiles in later Mesoamerican cultures.
What determines supply and demand for occupational pensions in Germany?
Authors: DUMMANN KATHRIN
Published: April 2008

Demographic change causes an undersupply of financial old age benefits within the statutory pay-as-you-go pension system in Germany. Therefore, the provision of occupational as well as private pensions has to be enhanced. However, there seems to be an undersupply of occupational pension provision particularly in small and medium sized enterprises (SMEs). Using survey data of the German Socio-Economic Panel (GSOEP) and the German SAVE survey, the present paper studies econometrically the determinants of occupational pension provision in Germany. It shows that occupational pensions depend not only on supply-side factors such as firm size and industry, but also on demand-side factors such as individual sociodemo-graphic attributes and people's savings motives.
Investigating erosion rates within a Japanese cypress plantation using Cs‐137 and Pb‐210ex measurements
Authors: Fukuyama Taijiro , Onda Yuichi , Takenaka Chisato , Walling Desmond E.
Published: April 2008

In Japan, soil erosion represents an important threat to the longer‐term sustainability of Japanese cypress plantations. Although it has been demonstrated that raindrop impact, rather than sheet or rill/gully erosion, is the dominant process in both sediment detachment and sediment transport at the point or hillslope scale in such plantations, the role of overland flow at the catchment scale has received little attention to date. To confirm the dominant erosion process operating in a Japanese cypress plantation catchment, we predicted the sediment transport capacities of both overland flow, expressed as a function of the upslope contributing area and the local slope gradient, and rainsplash, expressed as a topographic curvature, for 45 sampling points across the catchment. In addition, we compared the predicted values of sediment transport capacity and rainsplash with the erosion rates estimated using Cs‐137 and Pb‐210ex measurements. The results indicated a close correspondence between the local transport capacity of overland flow and the local erosion rates estimated using the radionuclide measurements. In contrast, there was no significant correlation between the topographic curvature and the erosion rates. Furthermore, the average radionuclide inventories for the catchment were much smaller than the local reference inventories, indicating net loss of eroded soil and radionuclides from the catchment. These results suggest that overland flow makes a significant contribution to surface soil erosion even on forested hillslopes. In addition, the results provide a useful demonstration of the potential for using radionuclide measurements to produce independent information on long‐term erosion rates, which can be used for investigating erosion processes and validating erosion models.
Constraining oceanic dust deposition using surface ocean dissolved Al
Authors: Han Qin , Moore J. Keith , Zender Charles , Measures Chris , Hydes David
Published: April 2008

We use measurements of ocean surface dissolved Al, a global Biogeochemical Elemental Cycling (BEC) ocean model, and the global Dust Entrainment and Deposition (DEAD) model to constrain dust deposition to the oceans. Our Al database contains all available measurements with best coverage in the Atlantic. Vertical profiles and seasonal data exist in limited regions. Observations show that surface dissolved Al is distributed similarly to the dust deposition predicted by DEAD and other models. There is an equatorial Atlantic Al maximum that decreases toward higher latitudes. There are high Al concentrations in the Mediterranean Sea and the Arabian Sea and low concentrations in the Pacific and the Southern Ocean. The ocean basins maintain more distinct Al profiles than Fe profiles in the upper ocean, consistent with a weaker biological influence on Al than Fe. The BEC‐predicted surface dissolved Al compares relatively well with observations. The Al distribution reflects the combined effects of Al input from dust and Al removal by particle scavenging and biological uptake by diatoms. Model‐observed biases suggest a southward shift of maximum dust deposition compared to current dust model predictions. DEAD appears to overestimate deposition north of 30°N in the Pacific and to underestimate deposition south of 30°N. Observed Al concentrations and the ocean model–predicted surface Al lifetime provide a semi‐independent method to estimate oceanic dust deposition. This technique indicates that DEAD may overestimate dust deposition to the north equatorial Atlantic but underestimate in other Atlantic regions, the Southern Ocean, and the Arabian Sea. However, spatial variations in aerosol Al solubility may also contribute to the model‐observation mismatch. Our results have implications for all dust‐borne ocean nutrients including Fe and demonstrate the potential of marine geochemical data to constrain atmospheric aerosol deposition fields.