bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of Nanocomposites Incorporating PZT Nanowires for Enhanced Energy Storage
Authors: Tang Haixiong , Lin Yirong , Andrews Clark , Sodano Henry A.
Published: April 2011

0–3 Piezoceramic polymer composites have attracted immense attention due to the flexibility afforded by the polymer matrix and the strong electromechanical coupling and high dielectric properties of the piezoceramic filler. The majority of research on these materials has focused on the effective piezoelectric properties of the piezoceramic polymer composites. However, the high dielectric strength of the polymer combined with the high permittivity of the ceramic filler make them well suited for use as high energy density capacitors and various pulsed power applications. Current work in this area has focused on the enhancement of the dielectric properties through a variation of nanoparticle composition or surface modifications to the fillers to enhance the energy density of composites. Recently, research and micromechanics modeling have shown that the filler aspect ratio plays an important role in increasing the effective dielectric properties of the composites. Therefore, unlike prior efforts, this work will focus on the effect of filler aspect ratio on the dielectric properties of the bulk nanocomposite. Nanocomposites were synthesized using lead zirconate titanate (PZT) with two different aspect ratio (nanowires, nanorods) fillers at various volume fractions dispersed in a polyvinylidene fluoride (PVDF) matrix. It was shown that the nanocomposites containing PZT nanowires (NWs) significantly increased the energy density compared to those containing lower aspect ratio PZT nanorods (NRs). The permittivity constants of composites containing PZT NWs were higher than those with PZT NRs at the same inclusion volume fraction. The experimental results also indicated that the high frequency loss tangent of nanocomposites with PZT NWs was smaller than those of PZT NRs, demonstrating the high electrical energy storage efficiency of the PZT NW composite. The PZT NW nanocomposites showed a 77.8% increase in energy density over the PZT NR nanocomposites, under an electric field of 15 kV/mm and 50% volume fraction. Because the energy density exhibits a quadratic relationship with the applied electric field, the performance enhancement through the use of NWs is even greater at higher electric fields. These results indicate that higher aspect ratio PZT nanowires shows promising potential to improve the energy density of nanocomposites, leading the development of advanced capacitors with high energy density.
Analysis of a Flexible Beam Actuated by Two Active SMA Wires
Authors: Zakerzadeh Mohammad R. , Sayyaadi Hassan
Published: April 2011

There are two ways of using SMAs as actuators for shape control of flexible structures; they can be either embedded within composite laminates or externally attached to the structures. Since the actuator can be placed at different offset distances from the beam, external actuators produce more bending moment and, consequently, more shape change. Such a configuration also allows introduction of fast convection cooling, very important in shape control applications that require a high-frequency response of SMA actuators. Although combination and modeling of externally-attached SMA actuator wires and strips have been widely considered by some researchers, these studies have some weaknesses that neglecting them would yield theoretically and experimentally erroneous results. In this work, the aforementioned limitations of attaching actuators to the smart structures have been removed and the modeling of a large deflection flexible beam actuated by two active SMA actuators is carried out. The Brinson constitutive equations for SMA materials are coupled with the nonlinear beam behavior and the coupled system of equations is numerically solved for some particular cases. The analysis method done in this paper can be easily extended to the complicated smart structures with externally-attached SMA wires.
Rolling the Black Pearl Over: Analyzing the Physics of a Movie Clip
Authors: Mungan Carl E. , Emery John D.
Published: April 2011

In the third movie (“At World's End”) in the Pirates of the Caribbean series, Jack Sparrow and his crew need to roll their ship (the Black Pearl) over in order to bring it back to the living world during a green flash at sunset. They do so by running back and forth from one side railing to the other on the top deck. In addition, Captain Barbossa orders that 18 cannons and a pile of barrels on the lower deck be cut loose to add mass to the running crew. In the movie they overturned the ship, but would they succeed under the same circumstances on a real galleon? In this paper, a numerical analysis using simple approximations is developed that suggests that what occurs in the movie is in fact realistic. Analyzing a popular film clip in this manner is a good way to arouse student interest, to teach about physics and numerical methods, and to model scientific reasoning when a situation is not as neatly defined as in a typical textbook problem.
Teaching Physics (and Some Computation) Using Intentionally Incorrect Simulations
Authors: Cox Anne J. , Junkin William F. , Christian Wolfgang , Belloni Mario , Esquembre Francisco
Published: April 2011

Computer simulations are widely used in physics instruction because they can aid student visualization of abstract concepts, they can provide multiple representations of concepts (graphical, trajectories, charts), they can approximate real-world examples, and they can engage students interactively, all of which can enhance student understanding of physics concepts. For these reasons, we create and use simulations to teach physics,1,2 but we also want students to recognize that the simulations are only as good as the physics behind them, so we have developed a series of simulations that are intentionally incorrect, where the task is for students to find and correct the errors.3
Revisiting the Ladder on a Wall Problem
Authors: Salu Yehuda
Published: April 2011

The problem of a ladder leaning on a wall has been a staple of introductory physics for years. It is discussed in numerous physics textbooks and in journals.1–4 Now, it even has an Internet presence. Postings from students seek help for “ladder on a wall” problems. A quick review of those postings would show that they all deal with frictionless walls. This is also how the situation is presented in most textbooks. One may get the impression that the friction between a ladder and a wall is always negligible, or that dealing with it is so difficult that it should be left out of the realm of introductory physics. The truth of the matter is that the magnitude of the friction coefficient between a ladder and a wall is not much different from that with the floor, and that friction with the wall is an important part of the conditions for having a static ladder. This paper derives a simple relationship between the friction coefficients of the ladder with the floor (μ1) and with the wall (μ2), when the ladder is in static equilibrium. Figure 1 shows the forces that act on a ladder that leans on a wall.
A Dynamic Knockout Reveals That Conformational Fluctuations Influence the Chemical Step of Enzyme Catalysis
Authors: Bhabha Gira , Lee Jeeyeon , Ekiert Damian C. , Gam Jongsik , Wilson Ian A. , Dyson H. Jane , Benkovic Stephen J. , Wright Peter E.
Published: April 2011

An
Escherichia coli
dihydrofolate reductase mutant is catalytically defective, because motions in the active site are impaired.
The Electron-Pairing Mechanism of Iron-Based Superconductors
Authors: Wang Fa , Lee Dung-Hai
Published: April 2011

The past three years have witnessed the discovery of a series of novel high-temperature superconductors. Trailing behind the cuprates, these iron-based compounds are the second–highest-temperature superconducting material family known to date. Despite the marked differences in the chemical composition, these materials share many properties with the cuprates and offer the hope of finally unveiling the secret of high-temperature superconductivity. The main theme of this review is the electron-pairing mechanism responsible for their superconductivity. We discuss the progress in this young field and point out the open issues.
Mutations in U4atac snRNA, a Component of the Minor Spliceosome, in the Developmental Disorder MOPD I
Authors: He Huiling , Liyanarachchi Sandya , Akagi Keiko , Nagy Rebecca , Li Jingfeng , Dietrich Rosemary C. , Li Wei , Sebastian Nikhil , Wen Bernard , Xin Baozhong , Singh Jarnail , Yan Pearlly , Alder Hansjuerg , Haan Eric , Wieczorek Dagmar , Albrecht Beate , Puffenberger Erik , Wang Heng , Westman Judith A. , Padgett Richard A. , Symer David E. , de la Chapelle Albert
Published: April 2011

Minor RNA splicing defects can cause a major human developmental disorder.
Surface-Plasmon Holography with White-Light Illumination
Authors: Ozaki Miyu , Kato Jun-ichi , Kawata Satoshi
Published: April 2011

A technique based on light-induced electronic excitations on a metal-film surface is used for three-dimensional color displays.
Coping with Chaos: How Disordered Contexts Promote Stereotyping and Discrimination
Authors: Stapel Diederik A. , Lindenberg Siegwart
Published: April 2011

Messiness makes people long for orderliness, which results in a rush to categorize and simplify.
Eosinophils Forestall Obesity
Authors: Maizels Rick M. , Allen Judith E.
Published: April 2011

Eosinophils in adipose tissue maintain metabolic homeostasis by controlling macrophage activity.
Increasing prevalence of smoke-free homes and decreasing rates of sudden infant death syndrome in the United States: an ecological association study
Authors: Behm Ilan , Kabir Zubair , Connolly Gregory N , Alpert Hillel R
Published: April 2011

Purpose

This study utilises an ecological design to analyse the relation between concurrent temporal trends in sudden infant death syndrome (SIDS) rates and prevalence of smoke-free households with infants in the USA, controlling for an important risk factor, infant supine sleep position.

Methods

Annual state-specific SIDS cases were computed using period linked birth/infant death files; the prevalence of 100% smoke-free homes with infants using Tobacco Use Supplement to the Current Population Survey data, and percentage of infants in supine sleep position from National Infant Sleep Position data, for years 1995–2006. Incidence rate ratios relating trends in SIDS cases and risk factors were determined using time-series negative binomial regression. Population-level health effects were assessed with secondhand smoke (SHS) exposure population attributable fractions and excess attributable SIDS deaths.

Results

For every 1% absolute increase in the prevalence of smoke-free homes with infants, SIDS rates decreased 0.4% from 1995 to 2006, controlling for supine sleep position. Nationally, it is possible that 20% of the 1326 total SIDS cases were attributable to childhood SHS exposure at home in 2006 with potentially 534 fewer infant deaths attributable to SHS exposure in 2006 than in 1995, owing to an increasing prevalence of 100% smoke-free homes with infants. Cumulatively, 4402 (lower 95% CI) to 6406 (upper 95% CI) excess SIDS cases may have been attributable to SHS exposure in the home over the 12-year study period.

Conclusions

The uptake of voluntary restrictions on smoking inside the home may present a public health benefit for infants in their first year of life. In light of inherent ecological study design limitations, these results warrant further individual level research linking postnatal SHS exposure and SIDS.
Canopy bulk density and canopy base height equations for assessing crown fire hazard inPinus radiataplantations
Authors: Ruiz-González Ana Daría , Álvarez-González Juan Gabriel
Published: April 2011

Crown fires combine high rates of spread, flame lengths, and intensities, making it virtually impossible to control them by direct action and having significant impact on soils, vegetation, and wildlife habitat. For these reasons, fire managers have great interest in preventive silviculture of forested landscapes to avoid the initiation and propagation of crown fires. The minimum conditions necessary to initiate and propagate crown fires are assumed to be strongly influenced by the stand structural variables canopy bulk density (CBD) and canopy base height (CBH). However, there is a lack of quantitative information on these variables and how to estimate them. To characterize the aerial fuel layers of Pinus radiata D. Don, the vertical profiles of canopy fuel in 180 sample plots of pure and even-aged P. radiata plantations were analysed. Effective CBD and CBH were obtained from the vertical profiles, and equations relating these variables to common stand variables were fitted simultaneously. Inclusion of the fitted equations in existing dynamic growth models, together with the use of current fire behaviour and hazard prediction tools, will provide a decision support system for assessing the crown fire potential of different silvicultural alternatives for this species.
Combining a predicted diameter distribution with an estimate based on a small sample of diameters
Authors: Mehtätalo Lauri , Comas Carlos , Pukkala Timo , Palahí Marc
Published: April 2011

The diameter distribution of a forest stand is of great interest in many situations, including forest management planning and the related prediction of growth and yield. The estimation of the diameter distribution may be based on, for example, a measured sample of diameters or the application of previously estimated parameter prediction models (PPMs), which relate the parameters of an assumed distribution function to some stand characteristics. We propose combining these two information sources. The approach is adopted from the mixed-effects modelling theory. The PPMs are treated as mixed-effects models, the residuals being stand effects. These stand effects are predicted using a small sample of tree diameters with the best linear predictor. A study conducted with a Spanish pine data set showed that in a situation where the predictors of the PPM include errrors, the prediction can be improved even by using a sample plot of as few as five sample trees. Vice versa, a distribution based on a sample plot of 3–15 sample trees can be significantly improved by utilizing existing PPMs. An additional simulation study was conducted to further investigate how the violation of different underlying assumptions of the method affects the performance.
Bite force and jaw biomechanics in the subterranean rodent Talas tuco-tuco (Ctenomys talarum) (Caviomorpha: Octodontoidea)
Authors: Becerra Federico , Echeverría Alejandra , Vassallo Aldo Iván , Casinos Adrià
Published: April 2011

The Talas tuco-tuco ( Ctenomys talarum Thomas, 1898) is a South American subterranean rodent that digs using both forelimbs and incisors, the latter being used when animals face hard soils and fibrous roots. In this rodent, the incisors are also used during intermale competition for mates. Bite forces were measured on wild females (n = 21) and males (n = 21) (both adult and young individuals) using a force transducer. Bite force was significantly higher in adult males than in females (32 vs. 27 N, respectively). Bite forces calculated on the physiological cross-section of jaw adductor muscles in dissected specimens were slightly higher than in vivo measurements. Regressions against body mass showed that bite force scaled with positive allometry, with slopes of 0.89 (females) and 0.99 (males). No significant differences were observed, neither in the slope nor in the y intercept of both sexes’ equations; therefore intersexual differences in bite forces observed in adults should mainly be due to size dimorphism. Considering that soil hardness of C. talarum’s typical habitat averages 100 N/cm2, and taking into account incisor’s cross-section, it was assessed that the pressure exerted by jaw adductor muscles at the incisors level is three times higher than that required for soil penetration.
A COMPARATIVE STUDY ON B →K*ℓ+ ℓ- AND $B \to K_0^\ast (1430) \ell^+ \ell^-$ DECAYS IN THE SUPERSYMMETRIC MODELS
Authors: BASHIRY V. , BAYAR M. , AZIZI K.
Published: April 2011

In this paper, we compare the branching ratio and rate difference of electron channel to muon channel of [Formula: see text] and B →K*ℓ+ℓ- decays, where [Formula: see text] is the p-wave scalar meson, in the supersymmetric models. MSSM with R parity is considered since considerable deviation from the standard model predictions can be obtained in B→Xs ℓ-ℓ+. Taking CQ1 and CQ2 about one which is consistent with the B→K*μ+μ- rate at low dileptonic invariant mass region (1 ≤ q2 ≤ 6 GeV 2). It is found that, firstly, the [Formula: see text] decay is measurable at LHC, secondly, in comparison with B →K*ℓ+ ℓ- decay a greater deviation in the [Formula: see text] decay can be seen. Measurement of these observables for the semileptonic rare [Formula: see text], in particular, at low q2 region can give valuable information about the nature of interactions within Standard Model or beyond.
SUPERSYMMETRIC LEFT–RIGHT MODELS WITH B-L ODD HIGGS DOUBLETS
Authors: BORAH DEBASISH
Published: April 2011

We study various possible Supersymmetric Left–Right (SUSYLR) models with Higgs doublets carrying B-L charge ±1: with single step symmetry breaking down to the Minimal Supersymmetric Standard Model (MSSM) as well as multistep symmetry breaking. Single step symmetry breaking can be achieved with the minimal field content of just Higgs doublet and bidoublets whereas multistep symmetry breaking can be realized only at the cost of including additional Higgs superfields. However, going beyond the minimal field content comes up with the exciting possibility of TeV scale intermediate symmetry which can have important implications in the ongoing collider experiments. We show that spontaneous parity violation can be achieved naturally in all these models and R-parity is spontaneously broken by the vacuum expectation value of B-L odd Higgs doublets. The tiny neutrino mass can arise from a double seesaw mechanism in the presence of additional singlet or triplet fermions. We show that gauge coupling unification can be achieved in these models with the possibility of TeV scale intermediate symmetry in some specific nonminimal versions.
NONSTANDARD CENTRAL LIMIT THEOREMS FOR MARKOV CHAINS
Authors: DE ANDRADE BERNARDO B. , GEYER CHARLES J.
Published: April 2011

We prove a nonstandard central limit theorem for strongly mixing stationary sequences using the "radically elementary" probability theory developed by Nelson (1987) and use this result to obtain a nonstandard Markov chain central limit theorem. An analogue of a Gaussian autoregressive process is used to illustrate how to obtain the rate of convergence. A Markov chain nonstandard functional central limit theorem is also proved under conditions similar to square integrability of the underlying martingale.
EFFECTS OF SULFUR SUBSTITUTIONAL IMPURITIES ON ZnO STRUCTURE USING DENSITY FUNCTIONAL THEORY
Authors: FLORES-HIDALGO MANUEL ALBERTO , BARRAZA-JIMÉNEZ DIANA , GLOSSMAN-MITNIK DANIEL
Published: April 2011

Zinc oxide ( ZnO ) electrical properties can be modified by addition of impurities or defects such as vacancies or other substances. We use sulfur ( S ) as a substitutional impurity and present a theoretical study on the characteristics of ZnO structures in its crystal form containing S in substitution of O . For theoretical calculations we used Density Functional Theory (DFT) with pseudopotentials and plane waves. ZnO in crystal form with S in substitution of O at heavy percentage was studied by analyzing properties like lattice characteristics, total energy, and gap energy. Lattice parameters a, b, c, and c/a ratio increase with the S -substituent percentage while the crystal stability decreases. Variation of gap energy shows a decreasing trend with increasing amount of substitution. In this paper, we provide a detailed data useful to identify the effects on ZnO in its crystal form when O is replaced by S that will help to predict if the structural changes on the modified ZnO structures may be suitable for applications in opto-electronics.
MAGNETIC CHARACTERIZATION OF WEB-LIKE CARBON NANOTUBES CATALYZED BY Fe2O3 VIA PULSED LASER ABLATION DEPOSITION (PLAD) TECHNIQUE
Authors: ISMAIL ISMAYADI , HASHIM MANSOR , YAHYA NOORHANA
Published: April 2011

Web-like carbon nanotubes were synthesized via Laser Ablation Deposition (PLAD) in a T-shape stainless steel chamber. An Nd -YAG laser with a 532 nm wavelength was used to irradiate a target of graphite and a catalyst, with a 5–7 ns pulsed width. Fe2O3 was used as a catalyst to produce a reactive graphite target. The vacuum level was kept at 5 Torr with argon gas flowing from the bottom of the chamber. The plume that was deposited on a glass substrate was then characterized using a Scanning Electron Microscope (SEM), Energy Dispersive X-ray (EDX) analysis, a Transmission Electron Microscope (TEM), and a Vibrating Sample Magnetometer (VSM). Web-like CNT structures were deposited on the glass substrate. These web-like structures were randomly aligned with sizes of 99 nm to 234 nm. TEM images confirmed that these web-like structures were CNTs. VSM results showed that the encapsulation of the Fe2O3 catalyst had influenced the magnetic properties of the CNTs. The magnetic property of CNTs was increased with the increasing amount of the Fe2O3 catalyst filling the CNTs. We assert that the starting catalyst material was transformed from hematite to magnetite via maghemite by a structural change under a reduced oxygen atmosphere during the laser ablation.
OPTICAL AND STRUCTURAL PROPERTIES OF SILVER NANOPARTICLES EMBEDDED IN INDIUM OXIDE FILMS
Authors: DAKHEL A. A. , HENARI F. Z.
Published: April 2011

Nanoparticles of silver-embedded indium oxide thin films have been prepared on glass and silicon substrates. Silver concentration were 3 wt.% and 5 wt.% as measured by X-ray fluorescence. X-ray diffraction reveals that indium oxide of these samples remains amorphous even after pre-annealing at 400°C. The optical absorption of the samples manifests the surface plasmon resonance (SPR) phenomena, which varies with Ag content. The Ag nanoparticles radius was estimated with Mie classical theory by using the SPR data analysis. The nonlinear optical properties of films on glass substrate were investigated using z-scan technique. Under cw excitation the films exhibit large reverse saturation absorption and negative nonlinearities. The real and imaginary parts of third order susceptibility of the samples were measured and the imaginary part which arise from the change in absorption is found to be dominant.
POLYCRYSTALLINE ZnO NANOWIRES OBTAINED BY PYROLIZING ZINC OXALATE-BASED NANOWIRES FROM TEMPLATE-ASSISTED SOLUTIONS
Authors: KUO DONG-HAU , CHANG HSIANG , CHENG JU-YIN
Published: April 2011

Polycrystalline ZnO nanowires composed of nanosized grains were produced by pyrolizing one-dimensional (1D) zinc oxalate-based nanowires at 450°C. The oxalate-based nanowires were synthesized at 25°C–100°C in an aqueous solution with the aid of a hexamethyleneamide (HMA) template and catalytic ammonia. Due to its low solubility in aqueous solution, zinc oxalate was not the popular reactant for the synthesis of ZnO . With a fixed ammonia concentration and a HMA/[ ZnC2O4 ⋅ H2O ] molar ratio of 1, the growth of zinc oxalate-based wires was investigated by changing growth temperature and growth duration. Different growth behaviors were observed and explained based upon the decomposition rate of [Formula: see text] complex and the interaction between zinc oxalate molecules and surfactants. The best growth condition was at 80°C for less than 1 h. After low-temperature calcination at 450°C, zinc oxalate-based nanowires were pyrolized into polycrystalline ZnO nanowires. This synthesis provides a simple route to prepare nanoparticle-covered ZnO nanowires.
EFFECT OF MAGNETIC FIELD ON THE PERISTALTIC TRANSPORT OF COUPLE STRESS FLUID IN A CHANNEL WITH WALL PROPERTIES
Authors: SANKAD G. C. , RADHAKRISHNAMACHARYA G.
Published: April 2011

Peristaltic transport of an incompressible couple stress fluid in a two-dimensional uniform channel with wall effects and in the presence of magnetic field has been studied. Using long wavelength approximation with low Reynolds number and dynamic boundary conditions, analytical expressions have been derived for velocity and stream function and the effects of pertinent parameters on these flow variables have been studied. The numerical results show that the time average velocity decreases with viscous damping force. Further, it has been observed that trapping occurs and the size of the trapped bolus decreases with Hartman number.
USING A CELLULAR-AUTOMATA MODEL TO INVESTIGATE THE EFFECTS OF GRAZING ON PLATEAU PIKA POPULATION DYNAMICS
Authors: LIU HANWU , ZHOU LI , LIU WEI , ZHOU HUAKUN
Published: April 2011

The plateau pika is a keystone species of Qinghai–Tibet plateau, but its overabundance aggravates the degradation of alpine meadow. Grazing is the most convenient manner to utilize alpine meadow. Grazing would change vegetation condition, that is, change the habitat of plateau pika and so lead to variation of plateau pika population. Based on ecological characteristics of plateau pika and alpine meadow, a cellular-automata model is established to investigate the influence of grazing on dynamics of plateau pika population. Vegetation shortens with the increase of grazing intensity. When grazing intensity is light, the height of vegetation under summer grazing, continuous grazing, rotational grazing and winter grazing decrease in turn. The ACC (average carrying capacity of plateau pika) is higher on degraded meadow and is lower on undegraded meadow. On undegraded meadow grazing affects the value of ACC, whereas, on degraded meadow grazing has slight effect on it. On undegraded meadow, plateau pika occupies all cells speedly, the amount of damaged cells and the average amount of live holes in occupied cells decrease or hold the line on temporal dimension. On degraded meadow, the dispersal of plateau pika is restrained, the amount of damaged cells and the average amount of live holes in occupied cells increase on temporal dimension.
A MECHANISTIC INDIVIDUAL-BASED TWO-HOST INTERACTION MODEL FOR THE TRANSMISSION OF A PARASITIC DISEASE
Authors: HEINZMANN DOMINIK , BARBOUR A. D. , TORGERSON PAUL R.
Published: April 2011

A mechanistic individual-based model for the infection dynamics of the parasite Echinococcus granulosus in a two host transmission system is proposed. The model describes the individual densities of the parasites in the two host populations. The architecture consists of two sub-processes for the acquisition and severity of infection in the host populations and a superimposed infection contact scheme between the hosts. The parasite dynamics within the host population are modeled using a compound mixed Poisson process for the sheep and a shot-noise process for the dogs. All model parameters are estimated based on available data. The fitted model is then used for simulations of the transmission dynamics between the two hosts to investigate environmental factors and evaluate intervention programs.
HOPF BIFURCATION ANALYSIS OF TWO SUNFLOWER EQUATIONS
Authors: WANG JINGNAN , JIANG WEIHUA
Published: April 2011

In this paper, two sunflower equations are considered. Using delay τ as a parameter and applying the global Hopf bifurcation theorem, we investigate the existence of global Hopf bifurcation for the sunflower equation. Furthermore, we analyze the local Hopf bifurcation of the modified equation with nonlinear relation about stem's increase, including the occurrence, the bifurcation direction, the stability and the approximation expression of the bifurcating periodic solution using the theory of normal form and center manifold. Finally, the obtained results of these two equations are compared, which finds that the result about the period of their bifurcating periodic solutions is obviously different, while the bifurcation direction and stability are identical.
THE EFFECT OF EXCHANGE RATE CHANGES ON TRADE IN EAST ASIA
Authors: THORBECKE WILLEM
Published: April 2011

This paper considers how exchange rates affect East Asian trade. The evidence indicates that exports produced within regional production networks depend on exchange rates throughout the region while labour-intensive exports depend on exchange rates in the exporting country. These results make sense since the majority of the value-added of processed exports come from imported parts and components while most of the value-added of labour-intensive exports comes from the domestic economy. Recent findings also indicate that imbalances between China and the US are a major outlier and that an appreciation of the Chinese yuan (CNY) is necessary to reduce these imbalances.
Tungsten Deposition by Metal-Chloride-Reduction Chemical Vapor Deposition
Authors: Hirose F. , Watanabe T. , Shibata A. , Momiyama K. , Suzuki T. , Miya H.
Published: April 2011

We successfully developed a fluorine-free tungsten deposition technique on a Si substrate at a substrate temperature in the range from 450 to 520°C by metal chloride reduction chemical vapor deposition (MCR-CVD). In this process, we first prepared a tungsten coil as a source material that can be heated by passing a current directly in itself at a temperature of 800°C. In a reaction chamber, the heated tungsten coil is exposed to RF excited Cl radicals to produce W chlorides to be delivered to the Si substrate. The adsorbed W chlorides are reduced to W by the Cl radical and a W film is grown on the Si surface. The residual Cl and F levels in the deposited W film were measured under the detection limit by x-ray photoelectron spectroscopy. The deposited W exhibited very low resistivity in the order of 10−5 Ω cm. The film conformality was examined using a trench-filling experiment, which suggests the suitability of the present process for the plug filling in VLSI production.
Chemical Mechanical Polishing of Ge Using Colloidal Silica Particles and H2O2
Authors: Peddeti Shivaji , Ong Patrick , Leunissen L. H. A. , Babu S. V.
Published: April 2011

The effects of colloidal silica particles, oxidizer (H2O2), and pH on the removal rates (RRs) of Ge have been evaluated. High removal and dissolution rates were obtained in the basic pH regions, likely caused by *OH radicals and rapid dissolution of the dissociation products of germanium hydroxides, while at pH 2, a RR of ∼420 nm/min was obtained with minimal dissolution. The surface quality of polished wafer coupons, measured using atomic force microscopy, was very good. A probable reaction mechanism for Ge removal as a function of pH is proposed.
Eukaryotic and prokaryotic contributions to colonic hydrogen sulfide synthesis
Authors: Flannigan Kyle L. , McCoy Kathy D. , Wallace John L.
Published: April 2011

Hydrogen sulfide (H2S) is an important modulator of many aspects of digestive function, both in health and disease. Colonic tissue H2S synthesis increases markedly during injury and inflammation and appears to contribute to resolution. Some of the bacteria residing in the colon can also produce H2S. The extent to which bacterial H2S synthesis contributes to what is measured as colonic H2S synthesis is not clear. Using conventional and germ-free mice, we have delineated the eukaryotic vs. prokaryotic contributions to colonic H2S synthesis, both in healthy and colitic mice. Colonic tissue H2S production is entirely dependent on the presence of the cofactor pyridoxal 5′-phosphate (vitamin B6), while bacterial H2S synthesis appears to occur independent of this cofactor. As expected, approximately one-half of the H2S produced by feces is derived from eukaryotic cells. While colonic H2S synthesis is markedly increased when the tissue is inflamed, and, in proportion to the extent of inflammation, fecal H2S synthesis does not change and tissue granulocytes do not appear to be the source of the elevated H2S production. Rats fed a B vitamin-deficient diet for 6 wk exhibited significantly diminished colonic H2S synthesis, but fecal H2S synthesis was not different from that of rats on the control diet. Our results demonstrate that H2S production by colonic bacteria does not contribute significantly to what is measured as colonic tissue H2S production, using the acetate trapping assay system employed in this study.
Toll-like receptor 3 signaling enables human esophageal epithelial cells to sense endogenous danger signals released by necrotic cells
Authors: Lim Diana M. , Wang Mei-Lun
Published: April 2011

The mechanisms by which gastroesophageal reflux disease esophagitis develops are controversial. Although many support the notion that caustic injury leads to reflux esophagitis, others have proposed that reflux esophagitis is caused by esophageal epithelial cytokine-mediated inflammation. We previously demonstrated that Toll-like receptor 3 (TLR3) is highly expressed and functional in the nontransformed human esophageal epithelial cell line EPC2-hTERT. In addition to activation by viral double-stranded RNA, TLR3 can be activated by endogenous mRNA released by necrotic cells. In the present study, we investigated the role of esophageal epithelial TLR3 to sense danger signals released by necrotic esophageal epithelial cells in vitro. Following induction of freeze-thaw necrosis, necrotic EPC2-hTERT cell supernatants (NCS) were used to stimulate EPC2-hTERT monolayers, leading to NF-κB-dependent induction of IL-8 mRNA expression. Responses to self-derived NCS were not observed in transformed gastrointestinal epithelial cell lines, including TE-1 and Caco-2 cells, suggesting that the ability to sense endogenous danger signals is unique to nontransformed esophageal epithelial cells. To determine the immunostimulatory role of epithelial RNA, EPC2-hTERT cells were stimulated with self-derived mRNA, which significantly induced IL-8 mRNA expression. Finally, suppression of TLR3 signaling in a DN-TLR3 cell line, hTERT-ΔTIR-TLR3, led to reduced NCS-induced IL-8 induction by both NCS and mRNA stimulation. Our results demonstrate that human esophageal epithelial cells can sense endogenous danger signals, in part through TLR3 signaling. This supports the concept that epithelial injury plays an inciting role in the pathogenesis of reflux-induced esophagitis, providing important insights into the mechanisms by which epithelial injury leads to inflammation.
Thirdhand smoke: a new dimension to the effects of cigarette smoke on the developing lung
Authors: Rehan Virender K. , Sakurai Reiko , Torday John S.
Published: April 2011

The underlying mechanisms and effector molecules involved in mediating in utero smoke exposure-induced effects on the developing lung are only beginning to be understood. However, the effects of a newly discovered category of smoke, i.e., thirdhand smoke (THS), on the developing lung are completely unknown. We hypothesized that, in addition to nicotine, other components of THS would also affect lung development adversely. Fetal rat lung explants were exposed to nicotine, 1-( N-methyl- N-nitrosamino)-1-(3-pyridinyl)-4-butanal (NNA), or 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), the two main tobacco-specific N-nitrosamine constituents of THS, for 24 h. We then determined key markers for alveolar paracrine signaling [epithelial differentiation markers surfactant phospholipid and protein synthesis; mesenchymal differentiation markers peroxisome proliferator-activated receptor γ (PPAR-γ), fibronectin and calponin], the BCL-2-to-Bax ratio (BCL-2/Bax), a marker of apoptosis and the involvement of nicotinic acetylcholine receptors (nAChR)-α3 and -α7 in mediating NNA's and NNK's effects on the developing lung. Similar to the effects of nicotine, exposure of the developing lung to either NNK or NNA resulted in disrupted homeostatic signaling, indicated by the downregulation of PPAR-γ, upregulation of fibronectin and calponin protein levels, decreased BCL-2/Bax, and the accompanying compensatory stimulation of surfactant phospholipid and protein synthesis. Furthermore, nAChR-α3 and -α7 had differential complex roles in mediating these effects. NNK and NNA exposure resulted in breakdown of alveolar epithelial-mesenchymal cross-talk, reflecting lipofibroblast-to-myofibroblast transdifferentiation, suggesting THS constituents as possible novel contributors to in utero smoke exposure-induced pulmonary damage. These data are particularly relevant for designing specific therapeutic strategies, and for formulating public health policies to minimize THS exposure.
Actinomyces Associated With Persistent Vaginal Granulation Tissue
Authors: Wai Clifford Y. , Nihira Mikio A. , Drewes Peter G. , Chang Joe S. , Siddiqui Momin T. , Hemsell David L.
Published: April 2011

Background: We report a case of symptomatic actinomycosis associated with vaginal suture erosion and granulation tissue refractory to conservative management, in an outpatient setting.

Case: Three months after total vaginal hysterectomy and uterosacral ligament vaginal vault suspension, a woman complained of painless, intermittent vaginal discharge and spotting. Despite cauterization of granulation tissue, vaginal spotting persisted for another month. On re‐examination, braided polyester suture that was found underlying the granulation tissue was removed. Recurrent symptoms, together with a biopsy revealing actinomycetes, prompted a trial of oral penicillin VK. With persistent symptoms and discomfort during attempts in the outpatient clinic, the woman eventually required suture removal in the operating room. Her symptoms subsequently resolved without recurrence, and no further antibiotic treatment was required.

Conclusions: Actinomyces may be associated with persistent granulation tissue and vault suspension suture material. In rare circumstances, when tissue debridement and suture removal in the clinic is unsatisfactory, surgical intervention in the operating room may be necessary. Ten days of antibiotic therapy alone did not eradicate the granulation tissue, and symptoms resolved only after complete removal of the underlying permanent suture.
Listeriosis Prevention Knowledge Among Pregnant Women in the USA
Authors: Ogunmodede Folashade , Jones Jeffery L. , Scheftel Joni , Kirkland Elizabeth , Schulkin Jay , Lynfield Ruth
Published: April 2011

Background: Listeriosis is a food‐borne disease often associated with ready‐to‐eat foods. It usually causes mild febrile gastrointestinal illness in immunocompetent persons. In pregnant women, it may cause more severe infection and often crosses the placenta to infect the fetus, resulting in miscarriage, fetal death or neonatal morbidity. Simple precautions during pregnancy can prevent listeriosis. However, many women are unaware of these precautions and listeriosis education is often
omitted from prenatal care.

Methods: Volunteer pregnant women were recruited to complete a questionnaire to assess their knowledge of listeriosis and its prevention, in two separate studies. One study was a national survey of 403 women from throughout the USA, and the
other survey was limited to 286 Minnesota residents.

Results: In the multi‐state survey, 74 of 403 respondents (18%) had some knowledge of listeriosis, compared with 43 of 286 (15%) respondents to the Minnesota survey. The majority of respondents reported hearing about listeriosis from a medical professional. In the multi‐state survey, 33% of respondents knew listeriosis could be prevented by not eating delicatessen meats, compared with 17% in the Minnesota survey (p = 0.01). Similarly, 31% of respondents to the multi‐state survey compared with 19% of Minnesota survey respondents knew listeriosis could be prevented by avoiding unpasteurized dairy products (p = 0.05). As for preventive behaviors, 18% of US and 23% of Minnesota respondents reported avoiding delicatessen meats and ready‐to‐eat foods during pregnancy, whereas 86% and 88%, respectively, avoided unpasteurized dairy products.

Conclusions: Most pregnant women have limited knowledge of listeriosis prevention. Even though most respondents avoided eating unpasteurized dairy products, they were unaware of the risk associated with ready‐to‐eat foods. Improved education of pregnant women regarding the risk and sources of listeriosis in pregnancy is needed.
Evaluation of Relative Yeast Cell Surface Hydrophobicity Measured by Flow Cytometry
Authors: Colling Lisa , Carter Richard N. , Essmann Michael , Larsen Bryan
Published: April 2011

Objective: To develop an efficient method for evaluating cell surface hydrophobicity and to apply the method to demonstrate the effects of fungal growth conditions on cell surface properties.

Methods: Yeast isolates were suspended in phosphate‐buffered saline and mixed with deep blue‐dyed polystyrene microspheres. Flow cytometry was used to detect the degree of microsphere binding to yeast cells. Different strains of yeast were compared for intrinsic microsphere binding activity and changes in growth conditions were invoked to modify the relative surface hydrophobicity.

Results: Commercially available blue‐dyed polystyrene microspheres showed strong fluorescence in the FL3 channel, whereas yeast cells did not show appreciable FL3 fluorescence. Microspheres and yeast were generally distinguishable on the
basis of size revealed by forward light scatter. This method showed a wide variation in intrinsic cell surface hydrophobicity among Candida albicans strains. Likewise, variation in hydrophobicity of non‐albicans yeast species was observed. Growth on
solid media, incubation at 25°C, or 250 mg/dl glucose concentration increased hydrophobicity compared with growth in liquid media, incubation at 37°C, or 50 mg/dl glucose, respectively.
Growth in 1 × 10−9
M estradiol had no appreciable effect on hydrophobicity.

Conclusions: Stained latex microspheres fluoresced in the FL3 channel of the flow cytometer and bound to yeast cells to an extent related to the surface hydrophobicity of the yeast. Binding detected by flow cytometry showed that clinical yeast
isolates varied in intrinsic binding capacity and this binding ability was altered by different growth conditions. The implications for virulence regulation among yeast isolates are discussed.
Diagnosis of Bacterial Vaginosis From Self‐Obtained Vaginal Swabs
Authors: Strauss Robert A. , Eucker Barbara , Savitz David A. , Thorp John M.
Published: April 2011

Objective: To determine the concordance between vaginal fluid Gram stains and pH obtained at speculum exam with similar stains and pH prepared from self‐obtained vaginal swabs.

Methods: Using vaginal fluid Gram stain, 129 pregnant women were screened for bacterial vaginosis at 24 to 29 weeks′ gestation. Two smears were collected from each woman during the same prenatal visit: the first was prepared from a selfobtained vaginal swab and the second from a physician‐obtained speculum examination. Vaginal pH was recorded for each swab. Kappa coefficient was used to quantify agreement between the two sets of results.

Results: When compared with the physician‐obtained smear, the ability of the self‐obtained Gram stain to diagnose bacterial vaginosis had a sensitivity of 77%, specificity of 97%, positive predictive value of 71% and negative predictive value of 97%. There was substantial agreement (weighted kappa= 0.82) between the two techniques in the ability to determine the grade of vaginal flora.

Conclusion: When compared with physician‐obtained vaginal smears, self‐obtained smears have substantial agreement in the diagnosis of bacterial vaginosis.
HOXB7 as a Prognostic Factor and Mediator of Colorectal Cancer Progression
Authors: Liao Wen-Ting , Jiang Dan , Yuan Jian , Cui Yan-Mei , Shi Xi-Wen , Chen Cui-Min , Bian Xiu-Wu , Deng Yong-Jian , Ding Yan-Qing
Published: April 2011

Purpose: This study was to investigate the clinicopathologic significance and potential role of HOXB7 in the development and progression of colorectal cancer (CRC).

Experimental Design: The relationship between HOXB7 expression and clinical characteristics of CRC was analyzed in 224 paraffin-embedded archived CRC specimens by immunohistochemistry (IHC). The effects of HOXB7 on cell growth and proliferation, as well as on tumorigenesis, were examined both in vitro and in vivo, using MTT assay, colony formation assay, cell cycle analysis, soft agar assay, and tumorigenesis in nude mice. Western blotting and real-time reverse transcriptase-PCR were performed to examine the impact of HOXB7 on the PI3K/Akt and MAPK signaling pathways.

Results: HOXB7 protein level was significantly correlated with advanced Dukes stage (P < 0.001), T stage (P = 0.012), distant metastasis (P = 0.042), higher proliferation index (P = 0.007) and poor survival of patients (P = 0.005). Enforced expression of HOXB7 in CRC cell lines significantly enhanced cell growth, proliferation and tumorigenesis. Conversely, knockdown of HOXB7 caused an inhibition of cell growth, proliferation, and tumorigenesis. We also showed that HOXB7 accelerated G0–G1 to S-phase transition concomitantly with upregulation of cyclin D1 and downregulation of p27Kip1. On the contrary, knockdown of HOXB7 caused G1–S-phase arrest, downregulation of cyclin D1 and upregulation of p27Kip1. Enforced expression of HOXB7 could enhance PI3K/AKT and MAPK pathway activity.

Conclusion: Our findings suggest that HOXB7 protein, as a valuable marker of CRC prognosis, plays an important role in the development and progression of human CRC. Clin Cancer Res; 17(11); 3569–78. ©2011 AACR.
HDAC Inhibitors Potentiate the Activity of the BCR/ABL Kinase Inhibitor KW-2449 in Imatinib-Sensitive or -Resistant BCR/ABL+ Leukemia Cells In Vitro and In Vivo
Authors: Nguyen Tri , Dai Yun , Attkisson Elisa , Kramer Lora , Jordan Nicholas , Nguyen Nguyen , Kolluri Nikhil , Muschen Markus , Grant Steven
Published: April 2011

Purpose: The purpose of this study was to determine whether histone deacetylase (HDAC) inhibitors (HDACI) such as vorinostat or entinostat (SNDX-275) could increase the lethality of the dual Bcr/Abl-Aurora kinase inhibitor KW-2449 in various Bcr/Abl+ human leukemia cells, including those resistant to imatinib mesylate (IM).

Experimental Design: Bcr/Abl+ chronic myelogenous leukemia (CML) and acute lymphoblastic leukemia (ALL) cells, including those resistant to IM (T315I, E255K), were exposed to KW-2449 in the presence or absence of vorinostat or SNDX-275, after which apoptosis and effects on signaling pathways were examined. In vivo studies combining HDACIs and KW2449 were carried out by using a systemic IM-resistant ALL xenograft model.

Results: Coadministration of HDACIs synergistically increased KW-2449 lethality in vitro in multiple CML and Ph+ ALL cell types including human IM resistant cells (e.g., BV-173/E255K and Adult/T315I). Combined treatment resulted in inactivation of Bcr/Abl and downstream targets (e.g., STAT5 and CRKL), as well as increased reactive oxygen species (ROS) generation and DNA damage (γH2A.X). The latter events and cell death were significantly attenuated by free radical scavengers (TBAP). Increased lethality was also observed in primary CD34+ cells from patients with CML, but not in normal CD34+ cells. Finally, minimally active vorinostat or SNDX275 doses markedly increased KW2449 antitumor effects and significantly prolonged the survival of murine xenografts bearing IM-resistant ALL cells (BV173/E255K).

Conclusions: HDACIs increase KW-2449 lethality in Bcr/Abl+ cells in association with inhibition of Bcr/Abl, generation of ROS, and induction of DNA damage. This strategy preferentially targets primary Bcr/Abl+ hematopoietic cells and exhibits enhanced in vivo activity. Combining KW-2449 with HDACIs warrants attention in IM-resistant Bcr/Abl+ leukemias. Clin Cancer Res; 17(10); 3219–32. ©2011 AACR.