bluuebunny/crossref_metadata_2025 huggingface dataset:
Perturbational calculations of parity-violating effects in nuclear-magnetic-resonance parameters
Authors: Weijo Ville , Manninen Pekka , Vaara Juha
Published: August 2005

We investigate the effects of the parity-violating electroweak interaction in the spectral parameters of nuclear magnetic resonance. Perturbational theory of parity-violating effects in the nuclear magnetic shielding is presented to the order of GFα, and in the indirect spin-spin coupling, to the order of GFα3. These leading-order parity-violating corrections are evaluated using analytical linear-response theory methods based on Hartree-Fock and density-functional theory reference states. Parity-violating contributions to spin-spin couplings are evaluated for the first time at the first-principles level. Calculations are carried out for two chiral halomethanes, bromochlorofluoromethane and bromofluoroiodomethane.
Morphological features related to micropipe closing in 4H-SiC
Authors: Yakimova R. , Vouroutzis N. , Syväjärvi M. , Stoemenos J.
Published: August 2005

The closing of micropipes during sublimation epitaxy has been studied. Shallow trenches are formed along the direction of the step-flow growth in the vicinity of closed micropipes. The trenches are related to a serious disturbance of the flowing steps and the formation of stacking faults in the (0001) basal plane as well as in the (11¯00) plane. A micropipe closes when the speed of the growth steps is higher than the spiral growth around the micropipe. This mechanism is related to a bending of the micropipe along the trench and the progressive emission of elementary screw dislocations along the trench. The morphology of the disturbed steps at the trenches and the related defects have been studied by transmission electron microscopy and atomic force microscopy. Supporting evidences are presented with optical micrographs from etched epilayers. Image forces, which are developed by the growth steps, stabilize the bending of the micropipes. The limitation of the bending is also discussed.
The spectra of mixed He3–He4 droplets
Authors: Fantoni S. , Guardiola R. , Navarro J. , Zuker A.
Published: August 2005

The diffusion Monte Carlo technique is used to calculate and analyze the excitation spectrum of He3 atoms bound to a cluster of He4 atoms by using a previously determined optimum filling of single-fermion orbits with well-defined orbital angular momentum L, spin S, and parity quantum numbers. The study concentrates on the energies and shapes of the three kinds of states for which the fermionic part of the wave function is a single Slater determinant: maximum L or maximum S states within a given orbit, and fully polarized clusters. The picture that emerges is that of systems with strong shell effects, whose binding and excitation energies are essentially determined by averages over configuration at fixed number of particles and spin, i.e., by the monopole properties of an effective Hamiltonian.
TmZn: A possible regenerator material for low-temperature cryocoolers
Authors: Jeromen Andrej , Trontelj Zvonko
Published: August 2005

The intermetallic compound TmZn has two low-temperature magnetic phase transitions and is a potential regenerator material. Application of a magnetic field to regulate the phase-transition temperature by influencing the specific heat cp(T) dependence in TmZn was investigated. The low-temperature heat capacity of a monocrystalline TmZn sample was measured as a function of magnetic field (up to 30 kOe). The anisotropy of the transition temperature in the applied magnetic field was modeled using ac susceptibility measurements. From the measured values, the TmZn regenerator specific heat was calculated taking into account both the temperature regulation and the anisotropy. A numerical simulation study of the TmZn regenerator was made. The results show an improvement in TmZn regenerator performance by the application of a magnetic field and employment of the transition anisotropy. The minimal cold chamber temperature was lowered from 11.76 to 9.77 K by the application of a magnetic field of 30 kOe. The performance of the TmZn regenerator is compared with the existing regenerator materials, Er3Ni, Pb, HoCu2, and Er50Pr50.
Phase-space overlap measures. I. Fail-safe bias detection in free energies calculated by molecular simulation
Authors: Wu Di , Kofke David A.
Published: August 2005

We consider ways to quantify the overlap of the parts of phase space important to two systems, labeled A and B. Of interest is how much of the A-important phase space lies in that important to B, and how much of B lies in A. Two measures are proposed. The first considers four total-energy distributions, formed from all combinations made by tabulating either the A-system or the B-system energy when sampling either the A or B system. Measures for A in B and B in A are given by two overlap integrals defined on pairs of these distributions. The second measure is based on information theory, and defines two relative entropies which are conveniently expressed in terms of the dissipated work for free-energy perturbation (FEP) calculations in the A→B and B→A directions, respectively. Phase-space overlap is an important consideration in the performance of free-energy calculations. To demonstrate this connection, we examine bias in FEP calculations applied to a system of independent particles in a harmonic potential. Systems are selected to represent a range of overlap situations, including extreme subset, subset, partial overlap, and nonoverlap. The magnitude and symmetry of the bias (A→B vs B→A) are shown to correlate well with the overlap, and consequently with the overlap measures. The relative entropies are used to scale the amount of sampling to obtain a universal bias curve. This result leads to develop a simple heuristic that can be applied to determine whether a work-based free-energy measurement is free of bias. The heuristic is based in part on the measured free energy, but we argue that it is fail-safe inasmuch as any bias in the measurement will not promote a false indication of accuracy.
Plasma oscillations in two-dimensional electron channel with nonideally conducting side contacts
Authors: Satou A. , Ryzhii V. , Chaplik A.
Published: August 2005

We calculate the spectrum and damping rate of plasma oscillations in a two-dimensional electron channel with striplike side contacts, taking into account the finite value of the conductivity of side contacts. We use a hydrodynamic electron-transport model for electrons both in the two-dimensional electron channel and contacts, with the Poisson equation for the self-consistent electric potential. It is shown that in the real channels the damping rate can markedly increase due to the influence of nonideally conducting side contacts.
Indentation stress dependence of the temperature range of microscopic superelastic behavior of nickel-titanium thin films
Authors: Zhang Yijun , Cheng Yang-Tse , Grummon David S.
Published: August 2005

The microscopic superelastic behavior of thin-film NiTi is investigated by instrumented indentation experiments conducted at different temperatures. The indentation-induced superelastic effect is found to be persistent to about 100K above the austenite transformation finish temperature (Af). In contrast, the upper temperature where superelastic effect exists is only around Af plus 40K in uniaxial tension and compression tests, beyond which the plasticity of the austenite phase overwhelms the transformation-induced superelasticity. By combining the Clausius-Clapeyron equation and spherical cavity model for indentation, we show that the high hydrostatic pressure under the indenter is capable of elevating the transformation temperatures and increase the upper temperature limit of indentation-induced superelastic behavior.
Growth of epitaxial InAs nanowires in a simple closed system
Authors: Park H. D. , Prokes S. M. , Cammarata R. C.
Published: August 2005

The epitaxial growth of InAs nanowires on an InAs(111) substrate in a sealed quartz tube is described. The method is quite simple and fast, and uses only a bare InAs substrate and a gold colloid coated InAs(111) substrate. High quality InAs nanowires can be produced by this technique, with the nanowire diameter controllable by the variation of growth temperature. The composition of the seed particle at the tip of the nanowire indicates that the nanowires grew via the vapor-liquid-solid growth mechanism but with Au–In as the liquid alloy.
On the relation between neoclassical transport and turbulent transport
Authors: Shaing K. C.
Published: August 2005

It is demonstrated through the flux-force relationship in the neoclassical theory that when neoclassical transport fluxes are improved, the damping rate of the radial electric field of the zonal flow is reduced. This, in turn, leads to improved turbulent transport fluxes. Thus, two seemingly unrelated transport fluxes are intimately connected through the momentum equation, and the neoclassical flux-force relation. This also implies a method to improve turbulent transport by improving neoclassical fluxes.
Multiple wavelength time-of-flight sensor based on time-correlated single-photon counting
Authors: Buller Gerald S. , Harkins Ross D. , McCarthy Aongus , Hiskett Philip A. , MacKinnon Gordon R. , Smith George R. , Sung Raymond , Wallace Andrew M. , Lamb Robert A. , Ridley Kevin D. , Rarity John G.
Published: August 2005

This article describes a time-of-flight sensor based on multiple pulsed laser sources which utilizes time-correlated single-photon counting. The sensor has demonstrated good performance at ranges of up to 17 km in daylight conditions. Analysis techniques were developed to examine the returns from targets containing more than one scattering surface.
Design and performance of an eight-pole resistive magnet for soft x-ray magnetic dichroism measurements
Authors: Arenholz Elke , Prestemon Soren O.
Published: August 2005

To take full advantage of the strengths of soft x-ray magnetic dichroism (XMD) measurements for the detailed and quantitative characterization of multielement magnetic materials, we developed an eight-pole electromagnet that provides magnetic fields up to 0.9T in any direction relative to the incoming x-ray beam. The setup allows us to measure magnetic circular and linear dichroism spectra as well as to thoroughly study magnetization reversal processes with very high precision. Design constraints and system optimization for maximum peak field are discussed. The predicted current-field relation is in excellent agreement with experimental findings. A brief discussion of the key technical difficulties in developing a similar superconducting device with peak fields of 5T and ramping rates suitable for point-by-point full-field reversal in an XMD experiment is presented.
Work function reduction of graphitic nanofibers by potassium intercalation
Authors: Robinson V. S. , Fisher T. S. , Michel J. A. , Lukehart C. M.
Published: August 2005

Materials with low work functions hold great potential for improving the performance of thermionic energy converters and other thermionic emission devices. Thermionic electron energy distributions (TEEDs) of graphitic carbon nanofibers (GCNFs) with and without intercalated potassium are used to characterize performance under realistic operating conditions. TEEDs of intercalated GCNFs at temperatures of 600 and 700 °C reveal an effective work function of 2.2 eV, a reduction of 2.5 eV from the work function of the GCNF without intercalate. In addition, consistent with other published work, a narrowing of the electron energy spectrum’s width occurs with intercalation. This narrower energy distribution may indicate emission from hybridized carbon–potassium states.
Improvement of field emission characteristics of carbon nanotubes through metal layer intermediation
Authors: Jeong Taewon , Heo Jungna , Lee Jeonghee , Lee Sanghyun , Kim Wonseok , Lee Hyunjung , Park Sanghyun , Kim J. M. , Oh Taesik , Park Chongwyun , Yoo Ji-Beom , Gong Byoungyun , Lee Naesung , Yu SeGi
Published: August 2005

A method of fabricating carbon nanotube (CNT)-based field emitters has been studied to improve field emission characteristics. From the supplementary substrate coated with CNTs, CNTs were transferred to the objective substrate through the metal intermediation (MI) layer where the heat and pressure were applied. CNTs were vertically aligned on the objective substrate after removing the supplementary substrate. The field enhancement effect of emitters can be increased by the formation of the sharp edges through CNT transfer process. This MI process allows one to lower the processing temperature below 300 °C and form the patterned CNT emitter arrays.
Atomic structure in Zr70Cu29Pd1 metallic glass
Authors: Yang L. , Jiang J. Z. , Liu T. , Hu T. D. , Uruga T.
Published: August 2005

Local atomic structures of Pd, Cu, and Zr atoms in an as-prepared Zr70Cu29Pd1 glassy alloy and the annealed samples containing icosahedral quasicrystal have been investigated by Pd, Cu, and Zr K-edge extended x-ray absorption fine structure (EXAFS) measurements. It is found that Cu and Zr atoms have an icosahedral atomic surrounding. Cu atoms could locate at both center position and shell sites while Zr atoms most likely occupy the shell sites of icosahedron. Pd atoms neither substitute Zr atoms nor Cu atoms. They sit at octahedral interstices, which link up icosahedron and promote the growth of icosahedron into long-range-order icosahedral quasicrystal in the ternary Zr70Cu29Pd1 glassy alloy during annealing treatment.
Ag
9
Tl
Te
5
: A high-performance thermoelectric bulk material with extremely low thermal conductivity
Authors: Kurosaki Ken , Kosuga Atsuko , Muta Hiroaki , Uno Masayoshi , Yamanaka Shinsuke
Published: August 2005

We studied a high-performance thermoelectric material whose chemical formula is Ag9TlTe5. Ag9TlTe5 is simple and easy to prepare. Its highest dimensionless figure of merit (ZT) value is 1.23, obtained at 700K. The values of individual thermoelectric properties at 700K are 2.63×10−4Ωm for electrical resistivity, 319μVK−1 for Seebeck coefficient, and 0.22Wm−1K−1 for thermal conductivity. Ag9TlTe5 is a unique material combining extremely low thermal conductivity and relatively low electrical resistivity.
Experimental and theoretical evidence for vacancy-clustering-induced large voids in Czochralski-grown germanium crystals
Authors: Hens S. , Vanhellemont J. , Poelman D. , Clauws P. , Romandic I. , Theuwis A. , Holsteyns F. , Van Steenbergen J.
Published: August 2005

Optical inspection of polished Czochralski-grown Ge wafers typically reveals the presence of surface pits similar to the Crystal Originated Particles (COP’s) observed in silicon but in a wider variety of sizes and shapes. Computer simulation of vacancy clustering during the Cz germanium crystal growth suggests that the surface pits originate from large voids formed by the diffusion-limited clustering of an excess of vacancies.
A novel T-DNA vector design for selection of transgenic lines with simple transgene integration and stable transgene expression
Authors: Chen Song , Helliwell Christopher A. , Wu Li-Min , Dennis Elizabeth S. , Upadhyaya Narayana M. , Zhang Ren , Waterhouse Peter M. , Wang Ming-Bo
Published: August 2005

Plants transformed with Agrobacterium frequently contain T-DNA concatamers with direct-repeat (d / r) or inverted-repeat (i / r) transgene integrations, and these repetitive T-DNA insertions are often associated with transgene silencing. To facilitate the selection of transgenic lines with simple T-DNA insertions, we constructed a binary vector (pSIV) based on the principle of hairpin RNA (hpRNA)-induced gene silencing. The vector is designed so that any transformed cells that contain more than one insertion per locus should generate hpRNA against the selective marker gene, leading to its silencing. These cells should, therefore, be sensitive to the selective agent and less likely to regenerate. Results from Arabidopsis and tobacco transformation showed that pSIV gave considerably fewer transgenic lines with repetitive insertions than did a conventional T-DNA vector (pCON). Furthermore, the transgene was more stably expressed in the pSIV plants than in the pCON plants. Rescue of plant DNA flanking sequences from pSIV plants was significantly more frequent than from pCON plants, suggesting that pSIV is potentially useful for T-DNA tagging. Our results revealed a perfect correlation between the presence of tail-to-tail inverted repeats and transgene silencing, supporting the view that read-through hpRNA transcript derived from i / r T-DNA insertions is a primary inducer of transgene silencing in plants.
Functional similarities between phage λ Orf and
Escherichia coli
RecFOR in initiation of genetic exchange
Authors: Maxwell Karen L. , Reed Patricia , Zhang Rong-guang , Beasley Steven , Walmsley Adrian R. , Curtis Fiona A. , Joachimiak Andrej , Edwards Aled M. , Sharples Gary J.
Published: August 2005

Genetic recombination in bacteriophage λ relies on DNA end processing by Exo to expose 3′-tailed strands for annealing and exchange by β protein. Phage λ encodes an additional recombinase, Orf, which participates in the early stages of recombination by supplying a function equivalent to the
Escherichia coli
RecFOR complex. These host enzymes assist loading of the RecA strand exchange protein onto ssDNA coated with ssDNA-binding protein. In this study, we purified the Orf protein, analyzed its biochemical properties, and determined its crystal structure at 2.5 Å. The homodimeric Orf protein is arranged as a toroid with a shallow U-shaped cleft, lined with basic residues, running perpendicular to the central cavity. Orf binds DNA, favoring single-stranded over duplex and with no obvious preference for gapped, 3′-tailed, or 5′-tailed substrates. An interaction between Orf and ssDNA-binding protein was indicated by far Western analysis. The functional similarities between Orf and RecFOR are discussed in relation to the early steps of recombinational exchange and the interplay between phage and bacterial recombinases.
Gene expression evidence for remodeling of lateral hypothalamic circuitry in cocaine addiction
Authors: Ahmed Serge H. , Lutjens Robert , van der Stap Lena D. , Lekic Dusan , Romano-Spica Vincenzo , Morales Marisela , Koob George F. , Repunte-Canonigo Vez , Sanna Pietro Paolo
Published: August 2005

By using high-density oligonucleotide arrays, we profiled gene expression in reward-related brain regions of rats that developed escalated cocaine intake after extended access to cocaine (6 h per day). Rats allowed restricted daily access to cocaine (only 1 h) that displayed a stable level of cocaine intake and cocaine naive rats were used for controls. Four analysis methods were compared: Affymetrixmicroarray suite 4andmicroarray suite 5, which use perfect-match-minus-mismatch models, anddchipandrma, which use perfect-match-only models to generate expression values. Results were validated by RT-PCR in individual animals from an independent replication of the experiment. A small number of genes was associated with escalated cocaine intake (ESC genes). Unexpectedly, of the brain regions examined [prefrontal cortex, nucleus accumbens, septum, lateral hypothalamus (LH), amygdala, and ventral tegmental area], the LH was the most transcriptionally responsive in escalation of cocaine intake. Most of the ESC genes identified are also expressed during synaptogenesis and synaptic plasticity and include genes that code for several presynaptic and postsynaptic proteins involved in neurotransmission. These results suggest that LH intrinsic circuitry undergoes a structural reorganization during escalation of cocaine use. This remodeling of LH circuitry could contribute to the chronic deficit in reward function that has been hypothesized to drive the transition to drug addiction. Results also support the value of using multiple analysis strategies to identify the most robust changes in gene expression and to compensate for the biases that affect each strategy.
Numerical computation of diffusion on a surface
Authors: Schwartz Peter , Adalsteinsson David , Colella Phillip , Arkin Adam Paul , Onsum Matthew
Published: August 2005

We present a numerical method for computing diffusive transport on a surface derived from image data. Our underlying discretization method uses a Cartesian grid embedded boundary method for computing the volume transport in a region consisting of all points a small distance from the surface. We obtain a representation of this region from image data by using a front propagation computation based on level set methods for solving the Hamilton–Jacobi and eikonal equations. We demonstrate that the method is second-order accurate in space and time and is capable of computing solutions on complex surface geometries obtained from image data of cells.
The effect of smoke, dust, and pollution aerosol on shallow cloud development over the Atlantic Ocean
Authors: Kaufman Yoram J. , Koren Ilan , Remer Lorraine A. , Rosenfeld Daniel , Rudich Yinon
Published: August 2005

Clouds developing in a polluted environment tend to have more numerous but smaller droplets. This property may lead to suppression of precipitation and longer cloud lifetime. Absorption of incoming solar radiation by aerosols, however, can reduce the cloud cover. The net aerosol effect on clouds is currently the largest uncertainty in evaluating climate forcing. Using large statistics of 1-km resolution MODIS (Moderate Resolution Imaging Spectroradiometer) satellite data, we study the aerosol effect on shallow water clouds, separately in four regions of the Atlantic Ocean, for June through August 2002: marine aerosol (30°S–20°S), smoke (20°S–5°N), mineral dust (5°N–25°N), and pollution aerosols (30°N– 60°N). All four aerosol types affect the cloud droplet size. We also find that the coverage of shallow clouds increases in all of the cases by 0.2–0.4 from clean to polluted, smoky, or dusty conditions. Covariability analysis with meteorological parameters associates most of this change to aerosol, for each of the four regions and 3 months studied. In our opinion, there is low probability that the net aerosol effect can be explained by coincidental, unresolved, changes in meteorological conditions that also accumulate aerosol, or errors in the data, although further
in situ
measurements and model developments are needed to fully understand the processes. The radiative effect at the top of the atmosphere incurred by the aerosol effect on the shallow clouds and solar radiation is –11 ± 3 W/m
2
for the 3 months studied; 2/3 of it is due to the aerosol-induced cloud changes, and 1/3 is due to aerosol direct radiative effect.
Study of coordinative gene expression at the biological process level
Authors: Yu Tianwei , Sun Wei , Yuan Shinsheng , Li Ker-Chau
Published: August 2005

Motivation: Cellular processes are not isolated groups of events. Nevertheless, in most microarray analyses, they tend to be treated as standalone units. To shed light on how various parts of the interlocked biological processes are coordinated at the transcription level, there is a need to study the between-unit expressional relationship directly.

Results: We approach this issue by constructing an index of correlation function to convey the global pattern of coexpression between genes from one process and genes from the entire genome. Processes with similar signatures are then identified and projected to a process-to-process association graph. This top–down method allows for detailed gene-level analysis between linked processes to follow up. Using the cell-cycle gene-expression profiles for Saccharomyces cerevisiae, we report well-organized networks of biological processes that would be difficult to find otherwise. Using another dataset, we report a sharply different network structure featuring cellular responses under environmental stress.

Contact:  kcli@stat.ucla.edu

Supplementary information:  http://kiefer.stat.ucla.edu/lap2/download/KL_supplement.pdf
Friend, an integrated analytical front-end application for bioinformatics
Authors: Abyzov Alexej , Errami Mounir , Leslin Chesley M. , Ilyin Valentin A.
Published: August 2005

Friend is a bioinformatics application designed for simultaneous analysis and visualization of multiple structures and sequences of proteins and/or DNA/RNA. The application provides basic functionalities, such as structure visualization, with different rendering and coloring, sequence alignment and simple phylogeny analysis, along with a number of extended features to perform more complex analyses of sequence structure relationships, including structural alignment of proteins, investigation of specific interaction motifs, studies of protein–protein and protein–DNA interactions and protein super-families. It is also useful for functional annotation of proteins, protein modeling and protein folding studies. Friend provides three levels of usage: (1) an extensive GUI for a scientist with no programming experience, (2) a command line interface for scripting for a scientist with some programming experience and (3) the ability to extend Friend with user written libraries for an experienced programmer. The application is linked and communicates with local and remote sequence and structure databases.

Availability:  http://mozart.bio.neu.edu/friend

Contact:  ilyin@neu.edu
Simpleaffy: a BioConductor package for Affymetrix Quality Control and data analysis
Authors: Wilson Claire L. , Miller Crispin J.
Published: August 2005

Summary: Quality Control is a fundamental aspect of successful microarray data analysis. Simpleaffy is a BioConductor package that provides access to a variety of QC metrics for assessing the quality of RNA samples and of the intermediate stages of sample preparation and hybridization. Simpleaffy also offers fast implementations of popular algorithms for generating expression summaries and detection calls.

Availability: Simpleaffy can be downloaded from http://www.bioconductor.org

Contact:  cmiller@picr.man.ac.uk

Supplementary information: Additional information can be found on the supplementary website located at http://bioinformatics.picr.man.ac.uk
JIGSAW: integration of multiple sources of evidence for gene prediction
Authors: Allen Jonathan E. , Salzberg Steven L.
Published: August 2005

Motivation: Computational gene finding systems play an important role in finding new human genes, although no systems are yet accurate enough to predict all or even most protein-coding regions perfectly. Ab initio programs can be augmented by evidence such as expression data or protein sequence homology, which improves their performance. The amount of such evidence continues to grow, but computational methods continue to have difficulty predicting genes when the evidence is conflicting or incomplete. Genome annotation pipelines collect a variety of types of evidence about gene structure and synthesize the results, which can then be refined further through manual, expert curation of gene models.

Results: JIGSAW is a new gene finding system designed to automate the process of predicting gene structure from multiple sources of evidence, with results that often match the performance of human curators. JIGSAW computes the relative weight of different lines of evidence using statistics generated from a training set, and then combines the evidence using dynamic programming. Our results show that JIGSAW's performance is superior to ab initio gene finding methods and to other pipelines such as Ensembl. Even without evidence from alignment to known genes, JIGSAW can substantially improve gene prediction accuracy as compared with existing methods.

Availability: JIGSAW is available as an open source software package at http://cbcb.umd.edu/software/jigsaw

Contact:  jeallen@umiacs.umd.edu
Smokeless tobacco and coronary heart disease: a 12-year follow-up study
Authors: Johansson Sven-Erik , Sundquist Kristina , Qvist Jan , Sundquist Jan
Published: August 2005

Background Cigarette smoking has declined whereas the use of smokeless tobacco is increasing. There is an ongoing debate as to whether smokeless tobacco is a recommendable strategy to help smokers to quit. However, very few studies have examined the association between smokeless tobacco, namely snuff, and coronary heart disease, which implies that it has not been possible to provide scientific results for public health policies and clinical guidelines concerning the use of smokeless tobacco.

Design A follow-up study.

Methods A random sample of 3120 healthy men aged 30–74 years was interviewed in 1988 and 1989 and followed up to the year 2000 with regard to coronary heart disease. Cox regression was used to estimate the relative risk of coronary heart disease in six categories of smoking and snuffing habits, after adjustment for established risk factors for coronary heart disease.

Results Smokers, former smokers, and those who combined smoking and snuffing had significantly higher hazard ratios than never-smokers. The very highest hazard ratio was found among individuals combining smoking and snuffing. Daily snuffers had a hazard ratio of 1.62 (95% confidence interval 0.70–3.03) after adjustment for age.

Conclusions Even though the association between daily snuffing and coronary heart disease was non-significant, the hazard ratio was markedly increased. Therefore, smokers should not use smokeless tobacco in order to quit smoking, especially as safer alternatives are available. Further studies in different settings are required to provide scientific results for public health policies and clinical guidelines.
Effect of mild endurance exercise training and pravastatin on peripheral vasodilatation of forearm resistance vessels in patients with coronary artery disease
Authors: Allemann Yves , Vetter Christian , Kartal Nesrin , Eyer Stephan , Stengel Svenia Marit , Saner Hugo , Hess Otto Martin
Published: August 2005

Background Improved endothelial function may contribute to the beneficial effects of cholesterol lowering therapy in patients with coronary artery disease (CAD), but results of the effect of statin therapy on endothelial function are disparate in these patients. Exercise training has been reported to improve endothelial function of patients at risk of or with established CAD. The goal of the study was to compare the effect of mild exercise training or statin therapy on forearm endothelial function in CAD patients with average cholesterol levels.

Design and methods Twenty-eight sedentary male patients with angiographically documented CAD and average pretreatment total plasma cholesterol levels (5.1±0.9 mmol/l) aged 42–75 years were included. They were randomly assigned in a 2:1 order to either statin therapy (pravastatin, 40 mg daily) or exercise training therapy (mild endurance exercise three or more times a week). The effects of 10 weeks of either treatment on endothelium-dependent and independent vasodilation of forearm resistance vessels was assessed by plethysmography. Cardiopulmonary exercise testing was performed at baseline and after 10 weeks.

Results Ten weeks of pravastatin therapy significantly reduced low-density lipoprotein cholesterol (from 3.8±0.6 to 3.1±0.6 mmol/l at study end, P=0.04) and the ratio of total to high-density lipoprotein cholesterol (from 4.9±0.8 to 3.7±0.7 mmol/l, P=0.002). Exercise training did not significantly modify the lipid profile. Peak oxygen consumption, maximal achieved workload and exercise duration tended to improve in the exercise training group but remained unchanged in the pravastatin-treated group. Neither 10 weeks of pravastatin nor mild endurance exercise training improved endothelium-dependent or independent vasomotor function in forearm resistance vessels.

Conclusions In patients with CAD and average cholesterol levels, 10 weeks of treatment with mild endurance exercise training or with pravastatin failed to improve endothelium-dependent or independent vasomotor function in forearm resistance vessels.
Effects of exercise training on insulin-like growth factor-I expression in the skeletal muscle of non-cachectic patients with chronic heart failure
Authors: Hambrecht Rainer , Schulze Paul Christian , Gielen Stephan , Linke Axel , Möbius-Winkler Sven , Erbs Sandra , Kratzsch Jürgen , Schubert Andreas , Adams Volker , Schuler Gerhard
Published: August 2005

Background Chronic heart failure (CHF) is associated with progressive muscle atrophy and reduced local expression of insulin-like growth factor I (IGF-I).

Design The present study was designed to test the hypothesis that the local deficiency of IGF-I in the skeletal muscle of patients with CHF would respond to a 6-months aerobic training intervention. Therefore, 18 patients [mean age 52.4 (SD 4.8) years, left ventricular ejection function (LVEF) 27 (SD 6)%] were prospectively randomized to either 6 months of training or sedentary lifestyle.

Methods Serum levels of growth hormone (GH) were measured by immunofluorometric assay, IGF-I by competitive solid phase immunoassay. IGF-I expression was assessed in vastus lateralis biopsies by real-time PCR.

Results Exercise training led to a significant increase in peak oxygen uptake by 26% [from 20.3 (SD 3.3) ml/kg per min to 25.5 (SD 5.7) ml/kg per min, P=0.003 versus control]. Local expression of IGF-I increased significantly after exercise training by 81% [from 6.3 (SE 0.8) to 11.4 (SE 1.4) relative units, P=0.007 versus control] while IGF-I receptor expression was reduced by 33% [from 20.0 (SE 2.1) to 13.8 (SE 1.7) relative units, P=0.008 versus control]. Serum growth hormone (GH) rose modestly from 0.12 (SE 0.07) to 0.65 (SE 0.37) ng/ml in the training group ( P=0.043 versus baseline), however, this change was not significant compared to the control group ( P=0.848). IGF-I serum levels remained virtually unchanged.

Conclusions Exercise training improves local IGF-I expression without significant changes of systemic parameters of the GH/IGF-I axis. These findings indicate that exercise training has the therapeutic potential to attenuate peripheral skeletal muscle alterations in particular with respect to local IGF-I expression in patients with moderate CHF.
Risk factors for prolonged QTc among US adults: Third National Health and Nutrition Examination Survey
Authors: Benoit Stephen R. , Mendelsohn Aaron B. , Nourjah Parivash , Staffa Judy A. , Graham David J.
Published: August 2005

Background QT interval prolongation can lead to torsades de pointes, a potentially fatal arrhythmia. Although research exists on the relationship between QT prolongation and clinical outcome, few studies have described risk factors for prolonged QT interval in the general population.

Methods The Third National Health and Nutrition Examination Survey (NHANES III) collected electrocardiogram interval data on 8561 subjects over 40 years of age and projected results to the US population. QT was corrected for heart rate using Fridericia's formula. Logistic regression analyses were performed to identify factors independently associated with prolonged QTc interval, defined as being in the upper 5% of the population QTc interval distribution. Analyses were conducted separately for women and men as a result of differences in the QT distribution between the sexes and also because of potential effect modification. Analytical variables included age, race/ethnicity, electrolyte measurements, body mass index, the recent use of QT-prolonging drugs and past medical histories of stroke, thyroid disease, hypertension, diabetes and myocardial infarction.

Results Age, female sex, hypocalcemia (men), hypokalemia (women), and a history of thyroid disease and myocardial infarction (men) were associated with a prolonged QTc interval. In addition, taking QT-prolonging medications in the past month was associated with more than a twofold increase in the odds of prolonged QTc interval in both men and women.

Conclusions Healthcare practitioners should be aware that a prolonged QTc interval is a potential indicator of cardiovascular risk, and should exercise caution in prescribing potentially QT-prolonging medications to certain patients.
Prevalence of cardiovascular diseases and associated risk factors in a rural black population of South Africa
Authors: Alberts Marianne , Urdal Petter , Steyn Krisela , Stensvold Inger , Tverdal Aage , Nel Johanna H. , Steyn Nelia P.
Published: August 2005

Background To determine the prevalence and associated risk factors of cardiovascular diseases in a rural adult black population from Limpopo Province in South Africa.

Design A cross-sectional study.

Methods A sample of 1608 women and 498 men aged 30 years and above participated in the study. Sociodemographic data, anthropometric measures (body mass index, waist/hip ratio), blood pressure and biochemical risk factors were measured. A global cardiovascular disease (CVD) risk profile was developed.

Results There was a high prevalence of tobacco use for men (57%) and women (35.4%), with women (28.1%) predominantly using smokeless tobacco. Alcohol use was very common in men (57.2%). Women weighed a great deal more than men, and 51.7% were either overweight or obese. Diabetes was diagnosed in 8.8 and 8.5% of women and men, respectively. High-density lipoprotein-cholesterol was relatively high, whereas 42.3% of women and 28.5% of men had low-density lipoprotein-cholesterol levels of 3 mmol/l or more. Hypertension (blood pressure ≥ 140/90 mmHg) was found in 25.5% of women and 21.6% of men. According to the Framingham formulae, 18.9% of women and 32.1% of men had a 20% or higher chance of having a CVD event in the next 10 years.

Conclusions There was a high prevalence of chronic disease risk factors in the rural, poor black community in Limpopo, South Africa. Consequently, the population had a higher than expected risk of developing a CVD event in the following 10 years when compared with similar studies in black Africans.
Mass flow and pressure-driven hyphal extension in Neurospora crassa
Authors: Lew Roger R.
Published: August 2005

Mass flow of cytoplasm inNeurospora crassatrunk hyphae was directly confirmed by injecting oil droplets into the hyphae. The droplets move in a manner similar to cytoplasmic particles and vacuoles within the hyphae. The direction of mass flow is towards the growing hyphal tips at the colony edge. Based on flow velocities (about 5 μm s−1), hyphal radius and estimates of cytoplasm viscosity, the Reynolds number is about 10−4, indicating that mass flow is laminar. Therefore, the Poiseulle equation can be used to calculate the pressure gradient required for mass flow: 0·0005–0·1 bar cm−1(depending on the values used for septal pore radius and cytoplasmic viscosity). These values are very small compared to the normal hydrostatic pressure of the hyphae (4–5 bar). Mass flow stops after respiratory inhibition with cyanide, or creation of an extracellular osmotic gradient. The flow is probably caused by internal osmotic gradients created by differential ion transport along the hyphae. Apical cytoplasm migrates at the same rate as tip extension, as do oil droplets injected near the tip. Thus, in addition to organelle positioning mediated by molecular motors, pressure-driven mass flow may be an integral part of hyphal extension.
Campylobacter jejuni activates mitogen-activated protein kinases in Caco-2 cell monolayers and in vitro infected primary human colonic tissue
Authors: MacCallum Amanda , Haddock Graham , Everest Paul H.
Published: August 2005

The mitogen-activated protein kinases (MAPKs) play a central role in many host signalling pathways. These signalling proteins are known to be involved in host responses against invasive bacteria including generation of chemotactic and inflammatory cytokines. It was hypothesized thatCampylobacter jejunimay activate MAPKs, as intestinal infection may induce a clinical and pathological picture of acute colonic inflammation. Infection of Caco-2 cell monolayers (human colonic epithelial cell line) and human colonic tissue withC. jejuni in vitrodemonstrated increased MAPK activity for ERK 1/2 (p44/42 MAPK), JNK and p38 MAPKs. Kinase activity and phosphorylated forms were increased in infected Caco-2 cells and human colonic explants, suggesting that these pathways are important in inflammatory responses induced byC. jejuniin man.
Loss of topoisomerase I function affects the RpoS-dependent and GAD systems of acid resistance in Escherichia coli
Authors: Stewart Natalee , Feng Jingyang , Liu Xiaoping , Chaudhuri Devyani , Foster John W. , Drolet Marc , Tse-Dinh Yuk-Ching
Published: August 2005

Acid resistance (AR) inEscherichia coliis important for its survival in the human gastrointestinal tract and involves three systems. The first AR system is dependent on the sigma factor RpoS. The second system (the GAD system) requires the glutamate decarboxylase isoforms encoded by thegadAandgadBgenes. The third system (the ARG system) requires the arginine decarboxylase encoded byadiA. Loss of topoisomerase I function fromtopAdeletion or Tn10insertion mutations lowered the resistance to killing by pH 2 or 2·5 treatment by 10-fold to >100-fold. The RpoS and GAD systems were both affected by thetopAmutation, but the ARG system of AR was not affected. Northern blot analysis showed that induction ofgadAandgadBtranscription in stationary phase and at pH 5·5 was decreased in thetopAmutant. Western blot analysis showed that thetopAmutation did not affect accumulation of RpoS, GadX or GadW proteins. Topoisomerase I might have a direct influence on the transcription of AR genes. This influence does not involve R-loop formation as the overexpression of RNase H did not alleviate the decrease of AR caused by thetopAmutation. The effect of thetopAmutation could be suppressed by anhnsmutation, so topoisomerase I might be required to counteract the effect of H-NS protein on gene expression, in addition to its influence on RpoS-dependent transcription.
The MAP kinase Mkc1p is activated under different stress conditions in Candida albicans
Authors: Navarro-García Federico , Eisman Blanca , Fiuza Sonia M. , Nombela César , Pla Jesús
Published: August 2005

Candida albicansis an opportunistic pathogen that has adapted to live and grow in the human body as its natural environment. Under these conditions, this fungus faces numerous challenges, including oxidative, osmotic and enzymic processes that may damage external and internal structures. In view of the key role of MAP kinase signalling pathways in the physiology ofC. albicans, the effect of agents mimickingin vivoenvironmental conditions on the activation of the p42-44 MAP kinases has been analysed. It has been found that Mkc1p is phosphorylated in the presence of oxidative stress, changes in osmotic pressure, cell wall damage and a decrease in the growth temperature. This phosphorylation is dependent on Pkc1p, indicating that both proteins operate in the same signalling pathway inC. albicans. Under some stimuli, the phosphorylation of Mkc1p required the presence of Hog1p, the MAP kinase of the high osmolarity glycerol (HOG) pathway. This suggests the existence of a new regulatory role, at least under some conditions, for these MAP kinase pathways in yeast.
Escherichia coli O157 : H7 forms attaching and effacing lesions at the terminal rectum of cattle and colonization requires the LEE4 operon
Authors: Naylor Stuart W. , Roe Andrew J. , Nart Pablo , Spears Kevin , Smith David. G. E. , Low J. Christopher , Gally David L.
Published: August 2005

Enterohaemorrhagic Escherichia coli O157 : H7 is a human pathogen that causes no apparent disease in cattle, its primary reservoir host. Recent research has demonstrated that E. coli O157 : H7 predominately colonizes the distal few centimetres of the bovine rectum, and in this study, the LEE4 operon encoding a type III secretion system translocon and associated proteins was shown to be essential for colonization. A deletion mutant of LEE4 failed to colonize cattle, in contrast to a co-inoculated strain containing a chromosomal complement of the operon, therefore fulfilling ‘molecular’ Koch's postulates for this virulence determinant. In addition, attaching and effacing (A/E) lesions were detectable in E. coli O157 : H7 microcolonies from the terminal rectum of both naturally and experimentally colonized cattle when examined by transmission electron microscopy. This study proves that type III secretion is required for colonization of cattle by E. coli O157 : H7, and that A/E lesion formation occurs at the bovine terminal rectum within E. coli O157 : H7 microcolonies. The research confirms the value of using type III secreted proteins as vaccine candidates in cattle.
Analysis of a failed jurisdictional claim
Authors: Shafer William E. , Gendron Yves
Published: August 2005

Purpose

The American Institute of Certified Public Accountants (AICPA) recently proposed a global consulting credential involving a diverse set of professions including accountancy, business law, and information technology. The proposal was widely debated in the professional literature, and was a divisive issue among CPAs. In late 2001, the AICPA membership voted against any further commitment to the credential. The purpose of this paper is to examine the global credential initiative in an effort to understand why professional jurisdictional claims may fail at the theorization stage.

Design/methodology/approach

The paper relies primarily on a qualitative review and analysis of archival materials and published articles and commentaries relating to the global credential project.

Findings

The analysis indicates that the AICPA failed to establish either the pragmatic or moral legitimacy of the proposed credential in the eyes of the audiences. This failure appears to be attributable to the sociopolitical environment in which the credential was promoted, and to flaws in the rhetoric used by the AICPA to articulate its jurisdictional claim.

Research limitations/implications

The paper demonstrates the importance of legitimacy to the ability to successfully theorize institutional changes.

Originality/value

This paper investigates how the AICPA theorized the global credential knowledge claim, and how theorization failed to persuade the audiences to support the credential.
Mandatory environmental disclosures in a legitimacy theory context
Authors: Luft Mobus Janet
Published: August 2005

Purpose

The purpose of this study is to examine the relationship between mandatory environmental performance disclosure and subsequent environmental regulatory performance.

Design/methodology/approach

Using legitimacy theory as the interpretive lens, regulatory non‐compliance disclosures threaten organizational legitimacy and non‐compliant firms are expected to respond to these threats. The potential effectiveness of different legitimation strategies for reducing these threats is evaluated.

Findings

Regression analysis shows a negative correlation between the mandatory disclosure of environmental legal sanctions and subsequent regulatory violations using firms in the US oil refining industry. These results are interpreted as demonstrating that subsequent regulatory compliance is a tactic employed by managers to minimize the delegitimizing effect of organizational impropriety revealed by mandatory accounting disclosures.

Practical implications

Implications for practice include linking financial reporting to environmental performance. This link gains greater importance as concern about the environmental effects of business operations becomes more acute within the investor, regulatory, and public interest arenas.

Originality/value

The paper makes original contributions to research on mandatory environmental disclosures that are embedded in US financial reporting. In addition, a conception of legitimacy theory that is broader than previously relied upon in accounting research literature is reviewed. The study examines a single industry within a single country. Further research may determine whether similar relationships are observed in other industries, and whether equivalent relationships can be examined in international settings. In addition, the possibilities and limits of regulatory compliance as a measure of environmental performance, and of environmental accounting as a policy tool in the governance of the commons are discussed.