bluuebunny/crossref_metadata_2025 huggingface dataset:
Pharmacotherapy of impaired mucociliary clearance in non‐CF pediatric lung disease. A review of the literature
Authors: Boogaard Ruben , de Jongste Johan C. , Merkus Peter J.F.M.
Published: September 2007

Mucoactive agents are used to treat a variety of lung diseases involving impaired mucociliary clearance or mucus hypersecretion. The mucoactive agents studied most frequently are N‐acetylcysteine (NAC), recombinant human DNase (rhDNase), and hypertonic saline. Studies on the efficacy of these have been mainly conducted in adults, and in patients with cystic fibrosis (CF). The exact role of mucoactive agents in children with non‐CF lung disease is not well established. We present an overview of the current literature reporting clinical outcome measures of treatment with NAC, rhDNase, and hypertonic saline in children. 2007;42:989–1001. © 2007 Wiley‐Liss, Inc.
Inhaled nitric oxide combined with prostacyclin and adrenomedullin in acute respiratory failure with pulmonary hypertension in piglets
Authors: Dani Carlo , Pavoni Vittorio , Corsini Iuri , Longini Mariangela , Gori Gabriele , Giannesello Lara , Perna Avio , Gritti Gaetano , Paternostro Ferdinando , Forestieri Annalisa , Buonocore Giuseppe , Rubaltelli Firmino F.
Published: September 2007

Our aim was to evaluate if the combined inhalation of both nitric oxide (iNO) and aerosolized prostacyclin or iNO and adrenomedullin (ADM) is more effective in lowering pulmonary arterial pressure (PAP) and improving oxygenation than nitric oxide alone in an animal model with pulmonary hypertension (PH). Moreover, we studied the effect on pulmonary mechanics, surfactant activity, and pulmonary oxidative stress of the different treatments. Twenty‐eight piglets with acute lung injury induced by lung lavages with saline were randomized to receive nitric oxide, nitric oxide plus prostacyclin, nitric oxide plus ADM or saline, after. Dynamic compliance, tidal volume, and airway resistance were measured. Lung tissue oxidation was evaluated by measuring total hydroperoxide and advanced oxidation protein products in bronchial aspirate samples. Surface surfactant activity was studied using Capillary Surfactometer. Inhaled nitric oxide combined with prostacyclin or ADM was more effective than nitric oxide alone in lowering PAP and improving oxygenation. Nitric oxide alone or combined increased lung compliance and tidal volume, and decreased airway resistance. No effects on surfactant surface activity and lung tissue oxidation were observed. The treatment with nitric oxide alone or combined with prostacyclin or ADM were effective in decreasing mean PAP and improving oxygenation in a piglet model of PH. However, nitric oxide plus prostacyclin and nitric oxide plus ADM were more effective than nitric oxide alone. The combination of aerosolized prostacyclin and ADM with nitric oxide might have a role in the treatment of infants with PH refractory to nitric oxide alone. 2007;42:1048–1056. © 2007 Wiley‐Liss, Inc.
Courses on mechanical ventilation in pediatrics: First experience in Spain
Authors: López Yolanda M. , Pilar Francisco J. , Medina Jose A. , López‐Herce Jesús , Pons Marti , Balcells Joan , Martinón‐Torres Federico , Modesto Vicente , García Juan A
Published: September 2007

Objective

To analyse the initial experience in mechanical ventilation courses held by the Respiratory Group of the Spanish Paediatric Intensive Care Society.

Materials and methods

From 2002 to 2006, 15 courses on paediatric mechanical ventilation were held in eight hospitals in Spain, attended by a total of 367 physicians (53.4 % trainees and 46.6 % staff physicians from Paediatrics, Neonatology or Emergency). An initial theoretical written test of 40 questions was completed by participants, followed by short theory classes and practical workshops based on clinical situations, with ventilators and ventilation simulators, with five to seven students per workshop. At the end of the course participants completed a theoretical written test, in which it was considered necessary to answer correctly at least 70% of the questions, a practical evaluation (with assessment grades from 1 to 5) and a written survey about the quality of the course (with assessment grades from 0 to 10).

Results

In the initial test, only 20% of students answered 70% of questions correctly, whilst in the final test 93% hit this target, (p < 0.001). In the practical evaluation, 96% of students demonstrated sufficient acquisition of practical skills (grades equal to or greater than 3). In the participant survey, the course methodology was rated at 8.7 ± 0.5, organisation 8.7 ± 0.4, teaching staff 9.2 ± 0.2, theoretical classes 8.7 ± 0.4 and practical sessions 8.8 ± 0.3.

Conclusions

Mechanical ventilation courses are a useful educational method for health professionals in theoretical and practical mechanical ventilation. Pediatr Pulmonol. 2007;42:1072–1077. © 2007 Wiley‐Liss, Inc.
Laser–target interaction during high‐power pulsed laser deposition of superconducting thin films
Authors: Fang Ranran , Zhang Duanming , Li Zhihua , Li Li , Tan Xinyu , Yang Fengxia
Published: September 2007

We present a theoretical model to describe the high‐power nanosecond pulsed laser ablation of multi‐elemental oxide superconductors by considering both the vaporization effect and the plasma shielding effect. Using as an example a YBa2Cu3O7 target, the numerical solutions are obtained by solving the heat flow equations using a finite difference method. We obtain the time dependence of temperature, the transmitted intensity and the ablation rate of the target. The numerical results agree well with the experimental data and are much better than without considering the effects of vaporization and plasma shielding, which indicates that the two effects in high‐power nanosecond laser ablation of superconductors must not be neglected. The present model will be helpful for the investigation of superconducting thin films prepared by pulsed laser deposition. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photoluminescence and thermally stimulated luminescence properties of CaSO4:Sm3+ and CaSO4:Ce3+,Sm3+; Sm3+ → Sm2+ conversion and high temperature dosimetry
Authors: Lapraz Dominique , Prévost Hildegarde , Angellier Gaëlle , Mady Franck , Benabdesselam Mourad , Dusseau Laurent
Published: September 2007

The photoluminescence (PL) and thermally stimulated luminescence (TSL) properties of CaSO4:Sm and CaSO4:Ce,Sm are studied. After X irradiation of CaSO4:Sm, an obvious Sm3+/Sm2+ redox process is observed. The Ce co‐doping is responsible for the presence of an intense TSL peak at about 485/500 °C, showing an interesting application in high temperature radiation dosimetry. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ruggero Ferdinando Antonio Guiseppe Vincenzo Oddi
Authors: Loukas Marios , Spentzouris Georgios , Tubbs R. Shane , Kapos Theodoros , Curry Brain
Published: September 2007

Long forgotten in his motherland but for a single discovery—a small circular tissue whose workings are as mysterious as its discoverer—a brilliant anatomist and physiologist, Oddi, gained his fame at the age of 23 years with his identification of the sphincter that would later be named in his honor. In 1984 Ruggero Oddi, was celebrated and revered in his native town of Perugia with a monument. Ruggero Oddi lived a tumultuous life, full of grief and tragedy, only to culminate in a lonely death while exiled in a foreign land. We now review the life of this contributor to modern anatomy.
Plant‐mediated indirect effects of carpenterworms on the insect communities attracted to fermented tree sap
Authors: Yoshimoto Jiichiro , Nishida Takayoshi
Published: September 2007

Carpenterworm (Lepidoptera, Cossidae) larvae bore into trunks of the oak Quercus acutissima, thereby promoting sap exudation, and prey on insects attracted to tree sap. We examined the interactions between carpenterworms and sap‐attracted insects to elucidate community‐level consequences of carpenterworms and to estimate the relative magnitudes of their direct and indirect effects on community structure. Species richness, total abundance, and Simpson's index of diversity (1/D) in tree sap communities were all significantly higher in carpenterworm‐associated patches (sap‐exuding patches that contained either larvae or larval nests) than in patches without evidence of carpenterworms. Abundance was also significantly higher in carpenterworm‐associated patches for 10 out of 14 taxonomic groups, and this difference was much greater in the following groups that are sensitive to resource increases: drosophilid flies (Drosophilidae), sap beetles (Nitidulidae), and rove beetles (Staphylinidae). These results indicate that carpenterworms increase community size indirectly by increasing resource abundance, which is supported by the results of structural equation modeling (SEM). SEM also revealed that the direct effect of carpenterworms on species richness was weaker than their indirect effect, suggesting that predation by carpenterworms does not determine community structure. Similarly, carpenterworms can increase the abundance of some taxa by increasing resource abundance, and the predation pressure from carpenterworms on most taxa may be minor.
An “O/S” Emulsion in a System Containing Tween 80 Surfactant and Hexadecane Oil
Authors: Al‐Bawab Abeer , Al‐Zamar Tamar , Friberg Stig E.
Published: September 2007

An emulsion was prepared from hexadecane and a surfactant, Tween 80 (a commercial polyoxyethylene sorbitan mono‐oleate), and the destabilization process was followed by visual observation of the separation of the emulsion aided by optical microscopy to estimate droplet size versus time. The emulsions had inferior stability, and the destabilization was completed within a few days. The results showed the emulsion to destabilize with the flocculation step immediately followed by coalescence. The separation rate was at a level calculated from the sedimentation rate of a dilute emulsion. This result was not anticipated, considering the large fraction of the dispersed phase, and an assumption was made as to what counteracting factors may have affected the results.
Effects of Arginine on Kinetics of Protein Aggregation Studied by Dynamic Laser Light Scattering and Tubidimetry Techniques
Authors: Lyutova Elena M. , Kasakov Alexei S. , Gurvits Bella Ya.
Published: September 2007

Prevention of undesirable protein aggregation is an extremely important strategy in protein science, medicine, and biotechnology. Arginine is one of the most widely used low molecular weight solution additives effective in suppressing aggregation, assisting refolding of aggregated proteins, and enhancing the solubility of aggregation‐prone unfolded molecules in vitro. However, the mechanism of suppression of protein aggregation by arginine is not well understood. To address the mechanism, two model systems have been investigated: protection of alcohol dehydrogenase (ADH) and insulin from heat‐ and dithiothreitol‐induced aggregation, respectively, in the presence of arginine. Using dynamic light scattering (DLS) technique, we have demonstrated the concentration‐dependent suppression of light scattering intensity of both ADH and insulin aggregates upon addition of arginine to the incubation medium, a significant effect being revealed in the physiological concentration range of arginine (1–10 mM). DLS studies showed that arginine shifted the populations of nanoparticles with higher hydrodynamic radii to the lower ones, suggesting that the preventive effect of arginine on the protein aggregation process arises because it suppresses intermolecular interactions among aggregation‐prone molecules. The results of turbidity measurements were also shown to be consistent with these findings.
Modeling of elemental carbon over Europe
Authors: Tsyro S. , Simpson D. , Tarrasón L. , Klimont Z. , Kupiainen K. , Pio C. , Yttri K. E.
Published: September 2007

The regional EMEP model has been applied to calculate EC concentrations over Europe for the years 2002–2004 using a new EC emission inventory. The results are compared with measurements from the CARBOSOL and EMEP EC/OC campaigns. The model underestimates EC concentrations by 19% on average, and the spatial correlation is 0.80. For individual sites, the model bias varies from −79 to 77% and the average temporal correlation is 0.53, varying from 0.25 to 0.79. The model flattens the north‐south EC gradient as it tends to overestimate EC for Nordic sites and underestimate EC for more southern sites. We have also studied the contributions of various processes to the model EC results. Using EC as a tracer of primary PM emissions from combustion sources we have made a preliminary evaluation of the anthropogenic EC (PM) emission. There are indications of a possible underestimation of EC emissions from traffic in some areas and both underestimation and overestimation of EC emissions from residential combustion for some European countries. The largest uncertainties probably lie in EC emissions from residential wood/fossil combustion and are associated with both emission factors and spatial and temporal variation. The need to develop accurate and time resolved wildfire emissions is emphasized. The effect of EC aging is shown be rather limited for most of Europe (1 to 4%). Changes in EC wet scavenging ratio have a noticeable effect on calculated EC (between 5 and 25% for most Europe and 30–40% in remote areas), but EC scavenging ratios are still poorly known.
Impact of scaling behavior on tropical cyclone intensities
Authors: Swanson Kyle L.
Published: September 2007

Theory suggests tropical cyclone maximum potential intensity increases with increasing ocean temperature. However, most tropical cyclones fail to achieve this maximum intensity. Instead, empirical studies suggest that tropical cyclone intensities are uniformly distributed between this maximum potential intensity and an intensity that marks the transition between tropical storm and hurricane scaling regimes. Here it is shown that this transition shifts significantly on interannual to interdecadal time scales in both the North Atlantic and Western North Pacific basins. The intensity at which this transition occurs effectively determines the fraction of tropical cyclones entering the hurricane scaling regime, and as such, strongly impacts the fraction of tropical cyclones that become intense. The increase in the fraction of intense tropical cyclones in recent decades results primarily from a shift in this scaling transition toward weaker winds rather than an increase in the maximum potential intensity directly attributable to rising sea surface temperatures. This scaling transition is shown to vary with sea surface temperature (SST) anomalies in the tropical cyclone main development regions relative to tropical mean SST anomalies, in contrast to the maximum potential intensity which varies with the SST itself.
Abrupt environmental change in Canada’s northernmost lake inferred from fossil diatom and pigment stratigraphy
Authors: Antoniades Dermot , Crawley Catherine , Douglas Marianne S. V. , Pienitz Reinhard , Andersen Dale , Doran Peter T. , Hawes Ian , Pollard Wayne , Vincent Warwick F.
Published: September 2007

An analysis of diatoms and fossil pigments in a sediment core from perennially ice‐covered Ward Hunt Lake at latitude 83°N in Nunavut, Canada revealed striking changes in diatom communities and sedimentary pigment concentrations during the last two centuries. Diatoms were found only in the upper 2.5 cm of the sedimentary record, and where present, diatom assemblages were composed almost entirely of Staurosirella pinnata. Photosynthetic pigments were present in low concentrations throughout the sedimentary profile, consistent with the ultra‐oligotrophic nutrient status of the lake. Pigment concentrations varied slightly in the lower sections of the core, and began to increase gradually at the 4 cm horizon followed by an increase of two orders of magnitude in the uppermost 2.5 cm. The changes observed in the sedimentary record of Ward Hunt Lake had similar trajectories to those observed post‐1850 elsewhere in the circumpolar Arctic, and imply that aquatic communities even in the most extreme northern lakes have been strongly impacted by recent climate warming.
Simulation of equatorial electrojet magnetic effects with the thermosphere‐ionosphere‐electrodynamics general circulation model
Authors: Doumbia V. , Maute A. , Richmond A. D.
Published: September 2007

In this work, the magnetic variations simulated by the NCAR thermosphere‐ionosphere‐electrodynamics general circulation model (TIE‐GCM) in the vicinity of the magnetic equator are examined to evaluate the ability of this model to reproduce the major features of the equatorial electrojet (EEJ) as observed on the ground as well as on board low‐altitude orbiting satellites. The TIE‐GCM simulates electric currents of various origins and reproduces their associated magnetic perturbations. We analyze the diurnal and latitudinal variations of the EEJ magnetic effects calculated on the ground in West Africa under approximately the same solar activity condition as in 1993 for the March equinox and June and December solstices. The latitudinal and local time structures of these simulated results correspond well to those that are observed. We also compare longitudinal variations of the midday EEJ magnetic perturbations observed by the CHAMP satellite with the model predictions. Although the simulations and observations both show multiple maxima and minima in longitude, the locations of these extrema often disagree. In the model most of the longitudinal variation of the magnetic variations is associated with nondipolar structure of the geomagnetic field. We find that the modeled contributions of the thermospheric migrating diurnal and semidiurnal tides to the magnetic perturbations have large longitudinal variations, and we suggest that an increase in the amplitude of these tides in the TIE‐GCM may cause them to play a major role in explaining the morphology of the EEJ longitudinal variation.
Transcriptional regulation of phospholipid biosynthesis is linked to fatty acid metabolism by an acyl-CoA-binding-protein-dependent mechanism in Saccharomyces cerevisiae
Authors: Feddersen Søren , Neergaard Thomas B. F. , Knudsen Jens , Færgeman Nils J.
Published: September 2007

In the present study, we have used DNA microarray and quantitative real-time PCR analysis to examine the transcriptional changes that occur in response to cellular depletion of the yeast acyl-CoA-binding protein, Acb1p. Depletion of Acb1p resulted in the differential expression of genes encoding proteins involved in fatty acid and phospholipid synthesis (e.g. FAS1, FAS2, ACC1, OLE1, INO1 and OPI3), glycolysis and glycerol metabolism (e.g. GPD1 and TDH1), ion transport and uptake (e.g. ITR1 and HNM1) and stress response (e.g. HSP12, DDR2 and CTT1). In the present study, we show that transcription of the INO1 gene, which encodes inositol-3-phosphate synthase, cannot be fully repressed by inositol and choline, and UASINO1 (inositol-sensitive upstream activating sequence)-driven transcription is enhanced in Acb1p-depleted cells. In addition, the reduction in inositol-mediated repression of INO1 transcription observed after depletion of Acb1p appeared to be independent of the transcriptional repressor, Opi1p. We also demonstrated that INO1 and OPI3 expression can be normalized in Acb1p-depleted cells by the addition of high concentrations of exogenous fatty acids, or by the overexpression of FAS1 or ACC1. Together, these findings revealed an Acb1p-dependent connection between fatty acid metabolism and transcriptional regulation of phospholipid biosynthesis in yeast. Finally, expression of an Acb1p mutant which is unable to bind acyl-CoA esters could not normalize the transcriptional changes caused by Acb1p depletion. This strongly implied that gene expression is modulated either by the Acb1p–acyl-CoA ester complex directly or by its ability to donate acyl-CoA esters to utilizing systems.
Activation-coupled membrane-type 1 matrix metalloproteinase membrane trafficking
Authors: Wu Yi I. , Munshi Hidayatullah G. , Snipas Scott J. , Salvesen Guy S. , Fridman Rafael , Stack M. Sharon
Published: September 2007

The transmembrane collagenase MT1-MMP (membrane-type 1 matrix metalloproteinase), also known as MMP-14, has a critical function both in normal development and in cancer progression, and is subject to extensive controls at the post-translational level which affect proteinase activity. As zymogen activation is crucial for MT1-MMP activity, an α1-PI (α1-proteinase inhibitor)-based inhibitor was designed by incorporating the MT1-MMP propeptide cleavage sequence into the α1-PI reactive-site loop (designated α1-PIMT1) and this was compared with wild-type α1-PI (α1-PIWT) and the furin inhibitory mutant α1-PIPDX. α1-PIMT1 formed an SDS-stable complex with furin and inhibited proMT1-MMP activation. A consequence of the loss of MT1-MMP activity was the activation of proMMP-2 and the inhibition of MT1-MMP-mediated collagen invasion. α1-PIMT1 expression also resulted in the intracellular accumulation of a glycosylated species of proMT1-MMP that was retained in the perinuclear region, leading to significantly decreased cell-surface accumulation of proMT1-MMP. These observations suggest that both the subcellular localization and the activity of MT1-MMP are regulated in a coordinated fashion, such that proMT1-MMP is retained intracellularly until activation of its zymogen, then proMT1-MMP traffics to the cell surface in order to cleave extracellular substrates.
A novel horse α-defensin: gene transcription, recombinant expression and characterization of the structure and function
Authors: Bruhn Oliver , Regenhard Petra , Michalek Matthias , Paul Sven , Gelhaus Christoph , Jung Sascha , Thaller Georg , Podschun Rainer , Leippe Matthias , Grötzinger Joachim , Kalm Ernst
Published: September 2007

Defensins are a predominant class of antimicrobial peptides, which act as endogenous antibiotics. Defensins are classified into three distinct sub-families: θ-, β-, and α-defensins. Synthesis of α-defensin has been confirmed only in primates and glires to date and is presumably unique for a few tissues, including neutrophils and Paneth cells of the small intestine. Antimicrobial activities of these peptides were shown against a wide variety of microbes including bacteria, fungi, viruses and protozoan parasites. In the present study, we report the characterization of the equine α-defensin DEFA (defensin α) 1. Transcription analysis revealed that the transcript of the gene is present in the small intestine only. An alignment with known α-defensins from primates and glires displayed a homology with Paneth-cell-specific α-defensins. DEFA1 was recombinantly expressed in Escherichia coli and subsequently analysed structurally by CD and molecular modelling. To examine the antimicrobial properties, a radial diffusion assay was performed with 12 different micro-organisms and the LD90 (lethal dose killing ≥90% of target organism) and MBC (minimal bactericidal concentration) values were examined. DEFA1 showed an antimicrobial activity against different Gram-positive and Gram-negative bacteria and against the yeast Candida albicans. Using viable bacteria in combination with a membrane-impermeable fluorescent dye, as well as depolarization of liposomes as a minimalistic system, it became evident that membrane permeabilization is at least an essential part of the peptide's mode of action.
A unified density-functional treatment of dynamical, nondynamical, and dispersion correlations
Authors: Becke Axel D. , Johnson Erin R.
Published: September 2007

In previous work we have introduced exact-exchange-based density-functional models of dynamical, nondynamical, and dispersion correlations. We have not yet, however, been able to combine these models into a single energy functional. The problem is that interaction curves in van der Waals complexes are too repulsive. A simple solution is proposed in the present work resulting in an exact-exchange-based energy functional for all chemical interactions, from the weakest (dispersion) to the strongest (molecular bonds).
Interpreting activity in H2O–H2SO4 binary nucleation
Authors: Bein Keith J. , Wexler Anthony S.
Published: September 2007

Sulfuric acid–water nucleation is thought to be a key atmospheric mechanism for forming new condensation nuclei. In earlier literature, measurements of sulfuric acid activity were interpreted as the total (monomer plus hydrate) concentration above solution. Due to recent reinterpretations, most literature values for H2SO4 activity are thought to represent the number density of monomers. Based on this reinterpretation, the current work uses the most recent models of H2O–H2SO4 binary nucleation along with perturbation analyses to predict a decrease in critical cluster mole fraction, increase in critical cluster diameter, and orders of magnitude decrease in nucleation rate. Nucleation rate parameterizations available in the literature, however, give opposite trends. To resolve these discrepancies, nucleation rates were calculated for both interpretations of H2SO4 activity and directly compared to the available parameterizations as well as the perturbation analysis. Results were in excellent agreement with older parameterizations that assumed H2SO4 activity represents the total concentration and duplicated the predicted trends from the perturbation analysis, but differed by orders of magnitude from more recent parameterizations that assume H2SO4 activity represents only the monomer. Comparison with experimental measurements available in the literature revealed that the calculations of the current work assuming aa represents the total concentration are most frequently in agreement with observations.
Thermodynamic model for water and high-pressure ices up to 2.2GPa and down to the metastable domain
Authors: Choukroun Mathieu , Grasset Olivier
Published: September 2007

We propose a thermodynamic model of the properties of liquid water and ices I, III, V, and VI that can be used in the ranges of 0–2200MPa and 180–360K. This model is the first to be applicable to all H2O phases in these wide ranges, which exceed the stability domain of all phases. Developing empirical or semiempirical expressions for the specific volumes of liquid water or ices has been necessary. The model has been tested on available experimental data sets. The specific volume of liquid water is reproduced with an accuracy better than 1%. The error on the specific volume of ices remains within 2%. The model has also been used to describe the melting curves of high-pressure ice polymorphs and compared with new Simon equations fitting available data. Our calculations suggest a slight revision of the triple point positions in the H2O phase diagram. We have ensured the reliability of our model up to 1.5GPa, and we have shown that it can be used with good confidence up to 2.2GPa. In order to show the validity of this model in the low-temperature domains, the melting curve of ice Ih in the water-ammonia system has been modeled. This curve is reproduced with good accuracy down to 180K, at a 1bar pressure. It shows that this model can be used in further studies for modeling equilibriums involving liquid or solid phases of H2O under pressure and for investigating the effect of inhibitors in complex water-rich systems.
Differential cross section for the H+D2→HD(v′=1,j′=2,6,10)+D reaction as a function of collision energy
Authors: Koszinowski Konrad , Goldberg Noah T. , Zhang Jianyang , Zare Richard N. , Bouakline Foudhil , Althorpe Stuart C.
Published: September 2007

We have measured differential cross sections (DCSs) for the HD (v′=1,j′=2,6,10) products of the H+D2 exchange reaction at five different collision energies in the range 1.48⩽Ecoll⩽1.94eV. The contribution from the less energetic H atoms formed upon spin-orbit excitation of Br in the photolysis of the HBr precursor is taken into account for two collision energies, Ecoll=1.84 and 1.94eV, allowing us to disentangle the two different channels. The measured DCSs agree well with new time-dependent quantum-mechanical calculations. As the product rotational excitation increases, the DCSs shift from backward to sideward scattering, as expected. We also find that the shapes of the DCSs show only a small overall dependence on the collision energy, with a notable exception occurring for HD (v′=1,j′=2), which appears bimodal at high collision energies. We suggest that this feature results from both direct recoil and indirect scattering from the conical intersection.
Universality in eight-arm star polystyrene and methylcyclohexane mixtures near the critical point
Authors: Jacobs D. T. , Braganza Clinton I. , Brinck Andy P. , Cohen Adam B. , Lightfoot Mark A. , Locke Christopher J. , Suddendorf Sarah J. , Timmers Henry R. , Triplett Angela L. , Venkataraman Nithya L. , Wellons Mark T.
Published: September 2007

Measurements of the coexistence curve and turbidity were made on different molecular mass samples of the branched polymer-solvent system eight-arm star polystyrene in methylcyclohexane near its critical point. We confirmed that these systems belong in the Ising universality class. The location of the critical temperature and composition as well as the correlation length, susceptibility, and coexistence curve amplitudes were found to depend on molecular mass and the degree of branching. The coexistence curve diameter had an asymmetry that followed a “complete scaling” approach. All the coexistence curve data could be scaled onto a common curve with one adjustable parameter. We found the coexistence curve amplitude to be about 12% larger for branched than linear polystyrenes of the same molecular mass in either solvent cyclohexane or methylcyclohexane. The two-scale-factor universality ratio R was found to be independent of molecular mass or degree of branching.
Analytical description of stochastic field-line wandering in magnetic turbulence
Authors: Shalchi A. , Kourakis I.
Published: September 2007

A nonperturbative nonlinear statistical approach is presented to describe turbulent magnetic systems embedded in a uniform mean magnetic field. A general formula in the form of an ordinary differential equation for magnetic field-line wandering (random walk) is derived. By considering the solution of this equation for different limits several new results are obtained. As an example, it is demonstrated that the stochastic wandering of magnetic field-lines in a two-component turbulence model leads to superdiffusive transport, contrary to an existing diffusive picture. The validity of quasilinear theory for field-line wandering is discussed, with respect to different turbulence geometry models, and previous diffusive results are shown to be deduced in appropriate limits.
High resolution spectroscopy for the ÃA12 state of CH3I+ by mass-analyzed threshold ionization/photodissociation
Authors: Lee Mina , Kim Myung Soo
Published: September 2007

Photodissociation of CH3I+ in the ground vibronic state generated by mass-analyzed threshold ionization resulted in a superb spectrum for the first excited electronic state (ÃA12) with hardly any spurious peak. Rotational structure in the spectrum could be resolved by using a single mode laser. This structure for one vibronic band, 213161, was analyzed with the assumption of Hund’s case (a) scheme both in the ground and excited electronic states.
Hopping rates and concentrations of mobile fluoride ions in Pb1−xSnxF2 solid solutions
Authors: Ahmad Mohamad M. , Yamada Koji
Published: September 2007

In the present paper, the ion dynamics and relaxation of fluoride ions in Pb1−xSnxF2 (with x=0.2–0.6) solid solutions, prepared by mechanochemical milling, are studied in the conductivity formalism over wide ranges of frequencies and temperatures. The conductivity spectra of the investigated materials are analyzed by the Almond-West (AW) power-law model. The estimated values of the hopping rates and the dc conductivity of different compositions are thermally activated with almost the same activation energy. The calculated values of the concentration of mobile ions, nc, are almost independent of temperature and composition for x=0.2–0.4. The maximum value of nc is obtained for the x=0.6 sample, although it does not show the maximum conductivity. Therefore, the composition dependence of the ionic conductivity of these solid solutions could be explained based on the extracted parameters. The results presented in the current work indicate that the AW model represents a reasonable approximation of the overall frequency-dependent conductivity behavior of the investigated materials. The conductivity spectra at different temperatures for each composition are successfully scaled to a single master curve, indicating a temperature-independent relaxation mechanism. For different compositions, however, the conductivity spectra cannot be scaled properly, indicating composition-dependent relaxation dynamics.
Superlow friction of ta-C lubricated by glycerol: An electron energy loss spectroscopy study
Authors: Joly-Pottuz L. , Matta C. , de Barros Bouchet M. I. , Vacher B. , Martin J. M. , Sagawa T.
Published: September 2007

Energy-filtering transmission electron microscopy (EFTEM) analysis coupled with the technique of samples preparation, focused ion beam, was used to study physical, chemical, and mechanical properties of diamond-like carbon coatings (DLCs). Two different coatings (ta-C and a-C:H) were investigated, presenting different tribological behaviors in a boundary lubrication regime with glycerol. Electron energy loss spectroscopy appears to be a very powerful technique to characterize such DLC coatings. Special attention was paid to the maximum energy of the plasmon peak, which was used to evaluate some physical and mechanical properties of DLC coatings (density, sp3∕sp2 ratio, hardness). For ta-C superlubric coating, EFTEM results show a rearrangement of the DLC bulk structure under the friction process. Typically, the transformation of sp3 carbon into sp2 carbon was clearly observed and permits a self-adaptation of the coating, allowing it to support shearing without any delamination in spite of important compressive residual stresses in the coating. Moreover, the formation of graphitic carbon is evidenced at the top surface. This graphitic layer certainly helps the lubrication by glycerol in forming OH termination.
Vibrational state dependence of β and D asymmetry parameters: The case of the highest occupied molecular orbital photoelectron spectrum of methyl-oxirane
Authors: Contini G. , Zema N. , Turchini S. , Catone D. , Prosperi T. , Carravetta V. , Bolognesi P. , Avaldi L. , Feyer V.
Published: September 2007

The β angular asymmetry and D dichroic asymmetry parameters of the methyl-oxirane highest occupied molecular orbital (HOMO) band have been experimentally investigated with vibrational resolution using synchrotron radiation. A theoretical calculation of the Franck-Condon factors between vibrational ground state and different ionic vibrational states, in the Born-Oppenheimer harmonic approximation, has been performed in order to gain information on the vibrational states mainly involved in the HOMO photoelectron band. The general good agreement between theoretical and experimental results allows a reliable assignment of the major features. The experimental determination of β and D shows their dependence on the different final vibrational states. This paper reports, for the first time, experimental evidence of the dependence of the dichroic D parameter on the vibrational excitation of the ion.
Transitory behavior of a finite span synthetic jet
Authors: Cannelle Florine , Amitay Michael
Published: September 2007

The transitory behavior of a finite span synthetic jet, following the onset of a (pulse) input signal, was investigated and characterized using hot-wire anemometry and particle image velocimetry techniques. Measurements were performed in two planes: along the centerline of the synthetic jet slit (x-z plane) and across the jet slit (x-y plane) with varying stroke lengths and Reynolds numbers. The synthetic jet parameter matrix included actuation frequencies (fact) of 300 and 917Hz, stroke lengths from 16 to 50 times the slit width, and Reynolds numbers (based on the averaged orifice velocity) between 85 and 364. The transitory evolution of the synthetic jet consists of four stages: (1) in the x-y plane, the lead vortex pair advects downstream without spreading in the cross-stream direction while in the x-z plane, two vortices with opposite senses are formed (one on each end of the slit edge); (2) the vortex pair in the x-y plane moves in the cross-stream and streamwise directions, while the edge-vortices in the x-z plane move downstream and towards the center of the jet to form an array of vorticity concentrations of opposite sense; (3) accumulation of consecutive vortex pairs in the x-y plane, while in the x-z plane, consecutive pairs of the edge vortices propagate downstream and merge with the previous vortices, resulting in a three-dimensional vortex line; and (4) the combined leading vortex pair (in the x-y plane) detaches and moves downstream while the main jet penetrates through the leading vortex pair. During this time period the vortex lines (in the x-z plane) have a higher velocity in the center than the sides. Similar transitory behavior was observed for different stroke lengths, where as the stroke length increases the transient time decreases. Moreover, the spanwise vorticity concentrations lose their coherence as the stroke length increases.
Structural and vibrational analysis of nanocrystalline Ga1−xMnxN films deposited by reactive magnetron sputtering
Authors: Dias da Silva J. H. , Leite D. M. G. , Tabata A. , Cavalheiro A. A.
Published: September 2007

The structural and vibrational properties of nanocrystalline Ga1−xMnxN films deposited by reactive magnetron sputtering were analyzed in a wide composition range (0<x<0.18). The films were structurally characterized using x-ray diffraction with Rietveld refinement. The corresponding vibrational properties were investigated using micro-Raman and Fourier transform infrared spectroscopies. The films present a high crystallized fraction, crystallites having wurtzite structure, and high orientation texture with the c axis oriented perpendicular to the substrate surface. Rietveld analysis indicates that Mn atoms are incorporated substitutionally into Ga positions and show that the ionic character of cation-N bonds along the c axis is favored by the Mn incorporation. No evidence for Mn segregation or Mn rich phases was found in the composition range analyzed. Micro-Raman scattering spectra and infrared absorption experiments showed progressive changes with the increase of x and monotonic shifts of the GaN TO and LO peaks to lower frequencies. The structural and vibrational analyses are compared and the influence of Mn on the static and dynamic properties of the lattice is analyzed.
Optical and dielectric properties of junctionlike CdS nanocomposites embedded in polymer matrix
Authors: Mondal S. P. , Mullick H. , Lavanya T. , Dhar A. , Ray S. K. , Lahiri S. K.
Published: September 2007

CdS nanocomposites have been grown in a polymer (polyvinyl alcohol) matrix using a simple chemical bath deposition process. Transmission electron micrographs of nanocomposites grown at different solution temperatures revealed the formation of isolated as well as junctionlike structures. X-ray and selected area electron diffraction patterns show that the nanocomposites are polycrystalline with cubic CdS phase. Optical band gaps of nanocomposite films are found to decrease (3.26–2.86eV) with the increase in bath temperature from 70to90°C. Photoluminescence spectra show strong green emission attributed to the Cd2+ or Cd+ ion-related recombination via moderately deep trap states. The nanocomposites show an enormous enhancement of dielectric constant in polyvinyl alcohol matrix over a frequency range of 40Hz–10MHz.
Characterization of Fabry-Pérot microcavity modes in GaAs nanowires fabricated by selective-area metal organic vapor phase epitaxy
Authors: Hua Bin , Motohisa Junichi , Ding Ying , Hara Shinjiroh , Fukui Takashi
Published: September 2007

The authors present the formation of Fabry-Pérot cavity in single GaAs nanowire prepared by selective-area metal organic vapor phase epitaxy. The grown nanowires with hexagonal cross section are highly uniform and vertically oriented. Microphotoluminescence measurements of single GaAs nanowire exhibit periodic peaks in the intensity, which are suggestive of the longitudinal modes of a Fabry-Pérot cavity. The cavity is formed along the length of the nanowire and the (111) facets of both ends act as reflecting mirrors. Additionally, optical waveguides in GaAs nanowires were also observed.
Realization of In2O3 thin film transistors through reactive evaporation process
Authors: Dhananjay  , Chu Chih-Wei
Published: September 2007

In 2 O 3 thin films have been grown by reactive evaporation of indium in ambient oxygen. The films were structurally characterized by x-ray diffraction (XRD) and atomic force microscopy techniques. The results of XRD revealed that the films were polycrystalline in nature with preferred (222) orientation. The as-grown films were subjected to various annealing treatments to modulate the conductivity of the films for thin film transistors (TFTs). TFTs fabricated on SiO2 gate dielectric exhibited an on/off ratio of 104 and a field-effect mobility of 27cm2∕Vs. High on-state current makes them potential candidates for flat-panel display devices.
Deformation-induced rotational eutectic colonies containing length-scale heterogeneity in an ultrafine eutectic Fe83Ti7Zr6B4 alloy
Authors: Park Jin Man , Kim Do Hyang , Kim Ki Buem , Kim Won Tae
Published: September 2007

Microstructural investigations of an ultrafine eutectic Fe83Ti7Zr6B4 alloy reveal that spherical eutectic colonies are composed of nanoeutectic areas which are encapsulated by submicron eutectic areas indicating length-scale heterogeneity of lamellar structure. Furthermore, formation of the wavy and discontinuous shear bands indicative of dissipation of the shear stress are possibly caused by a rotation of the eutectic colonies along the submicron eutectic areas during deformation, leading to developing typical dimples on the fracture surface. The rotation of the eutectic colonies containing the length-scale heterogeneity is proposed to be responsible for macroscopic plasticity of the ultrafine eutectic Fe83Ti7Zr6B4 alloy.
Optically nonlinear effects in intersubband transitions of GaN∕AlN-based superlattice structures
Authors: Hofstetter Daniel , Baumann Esther , Giorgetta Fabrizio R. , Guillot Fabien , Leconte Sylvain , Monroy Eva
Published: September 2007

We report optically nonlinear processes related to near-infrared intersubband transitions in short period GaN∕AlN superlattices. The strong piezo- and pyroelectric effects in this material lead to intrinsic asymmetries in the electronic potential of the superlattice, and thus to strong nonlinearities of the optical susceptibility. Because of the large intersubband transition energy of nearly 1eV and the short lifetime of excited electrons in the upper quantum state, these nonlinear effects can be exploited for the fabrication of room temperature operated high-frequency detectors in the telecommunication wavelength range. At the same time, saturation effects due to resonant two-photon absorption could be observed.
An x-ray streak camera with high spatio-temporal resolution
Authors: Feng J. , Shin H. J. , Nasiatka J. R. , Wan W. , Young A. T. , Huang G. , Comin A. , Byrd J. , Padmore H. A.
Published: September 2007

An x-ray streak camera with high resolution in both temporal and spatial dimensions has been developed. It is achieved by using extraction-mesh acceleration and a large opening aperture magnetic solenoid lens design. High resolutions in the temporal and spatial dimensions can be retained in a wide 53ps time window. A temporal resolution of 233fs and a spatial resolution of 10μm have been demonstrated using a Au photocathode.
Inclusion of skin follicle traits in selection indices in breeding programs improves genetic gain in Australian fine-wool Merinos
Authors: Fozi M. Asadi , Van der Werf J. H. J. , Swan A. A.
Published: September 2007

Genetic parameters for skin follicle traits, wool traits, body weight, and number of lambs weaned per ewe joined were estimated for 5108 10-month-old Australian fine-wool Merinos born between 1990 and 1996. These animals were descended from 261 sires and 2508 dams. The skin follicle number index that is based on skin surface area, and primary, secondary, or total follicle density were introduced as possible early-age selection criteria estimated at 6 months of age. Heritability estimates for total, secondary, and primary follicle number index were 0.45 ± 0.04, 0.46 ± 0.04, and 0.38 ± 0.04, respectively. The genetic correlations of total follicle number index with clean fleece weight, mean fibre diameter, staple strength, coefficient of variation of fibre diameter, body weight, and number of lambs weaned were 0.16, –0.67, 0.00, 0.03, 0.22, and 0.22, respectively. Responses to selection on indices including and excluding follicle traits were calculated based on the genetic parameters estimated, and with annual responses calculated using an optimised age structure. On average, 10% greater response was predicted when total follicle number index was used as an additional selection criterion in different micron premium scenarios. In comparison, skin follicle density had a smaller effect on genetic improvement. The extra response was ~1%. Similar index responses were obtained when total follicle number index was used as a replacement selection criterion for clean fleece weight, mean fibre diameter, and coefficient of variation of fibre diameter for breeding objectives with low emphasis on fibre diameter. In objectives with high emphasis on fibre diameter, unfavourable correlated responses in staple strength and CV of fibre diameter limited the effectiveness of using total follicle number index as a selection criterion. Although the use of total follicle number index as an additional selection criterion can be favourable for some breeding objectives, measuring this trait is currently cost prohibitive to inclusion in Merino breeding programs.