bluuebunny/crossref_metadata_2025 huggingface dataset:
A model-assisted technique for characterization of in-plane magnetic anisotropy
Authors: Fan B. , Lo C. C. H.
Published: March 2012

This paper describes a novel technique for characterizing in-plane magnetic anisotropy, such as stress anisotropy. The method involves applying a radially spreading ac field to a test sample, and detects simultaneously the field signals emanating from the sample surface along different directions using an angular array of Hall effect sensors. The technique was applied to detect the stress-induced anisotropy in an annealed Fe plate. Under uniaxial tension, the field signal measured along the stress axis increases while that along the transverse axis decreases. The stress sensitivity of the technique was characterized in terms of the ratio of the field signals measured along and perpendicular to the stress axis. The ratios measured at both the first- and third-order harmonic frequencies increase monotonically with stress, with the latter showing a higher stress sensitivity. The stress dependence of the field signal ratio was modeled based on the magnetomechanical effect theory, and was found to agree with the experimental results.
Steady-state parameter sensitivity in stochastic modeling via trajectory reweighting
Authors: Warren Patrick B. , Allen Rosalind J.
Published: March 2012

Parameter sensitivity analysis is a powerful tool in the building and analysis of biochemical network models. For stochastic simulations, parameter sensitivity analysis can be computationally expensive, requiring multiple simulations for perturbed values of the parameters. Here, we use trajectory reweighting to derive a method for computing sensitivity coefficients in stochastic simulations without explicitly perturbing the parameter values, avoiding the need for repeated simulations. The method allows the simultaneous computation of multiple sensitivity coefficients. Our approach recovers results originally obtained by application of the Girsanov measure transform in the general theory of stochastic processes [A. Plyasunov and A. P. Arkin, J. Comput. Phys. 221, 724 (2007)10.1016/j.jcp.2006.06.047]. We build on these results to show how the method can be used to compute steady-state sensitivity coefficients from a single simulation run, and we present various efficiency improvements. For models of biochemical signaling networks, the method has a particularly simple implementation. We demonstrate its application to a signaling network showing stochastic focussing and to a bistable genetic switch, and present exact results for models with linear propensity functions.
Ring-type V-groove surface plasmon microresonator: The modal structure and Q-factor
Authors: Vardanyan Artashes , Haroyan Hovhannes , Babajanyan Arsen , Nerkararyan Khachatur , Lee Kiejin , Friedman Barry
Published: March 2012

We consider the formation of the surface plasmon polariton (SPP) mode in the ring-type V-groove structure. Closed-form expressions for the mode field distributions, resonant frequency, and total quality factor are obtained for the structure in a broad wavelength range. The model serves as a practical guide to design a SPP microcavity with sub-wavelength confinement in the transverse cross sectional directions.
Phase transitions between the rotator phases of paraffin investigated using silicon microcantilevers
Authors: Jung Namchul , Yun Minhyuk , Jeon Sangmin
Published: March 2012

Nanogram amounts of paraffin were coated onto a silicon cantilever, and the resonance frequency and deflection of the cantilever were measured as a function of temperature. Changes in the cantilever resonance frequency were used to determine the temperatures at which phase transitions between the rotator phases of tricosane, tetracosane, and pentacosane occurred. The phase transition measured using the cantilever was found to be more apparent than that obtained using conventional methods. The thermal hysteresis in the resonance frequency of a tetracosane-coated cantilever differed from that of the tricosane- and pentacosane-coated cantilevers, which was attributed to the even-odd effect on the crystal structures of paraffin. The even-odd effect was also observed in the temperature dependent deflection measurements. Further, the overshoot at the transition RV → crystal in the deflection measurement was observed and attributed to the steep increase in the modulus of paraffin during the transition.
Accurate quantum wave packet calculations for the F + HCl → Cl + HF reaction on the ground 12A′ potential energy surface
Authors: Bulut Niyazi , Kłos Jacek , Alexander Millard H.
Published: March 2012

We present converged exact quantum wave packet calculations of reaction probabilities, integral cross sections, and thermal rate coefficients for the title reaction. Calculations have been carried out on the ground 12A′ global adiabatic potential energy surface of Deskevich et al. [J. Chem. Phys. 124, 224303 (2006)10.1063/1.2192505]. Converged wave packet reaction probabilities at selected values of the total angular momentum up to a partial wave of J = 140 with the HCl reagent initially selected in the v = 0, j = 0–16 rovibrational states have been obtained for the collision energy range from threshold up to 0.8 eV. The present calculations confirm an important enhancement of reactivity with rotational excitation of the HCl molecule. First, accurate integral cross sections and rate constants have been calculated and compared with the available experimental data.
Electronic and structural properties of InAs/InP core/shell nanowires: A first principles study
Authors: dos Santos Cláudia L. , Piquini Paulo
Published: March 2012

The one-dimensional character of the nanowires (NWs), with large surface to volume ratios, allows one to accommodate internal strains that would not be achieved in composite bulk materials with large mismatches. This opens a vast field to explore new materials with specific properties. One of the ways to efficiently exploit this characteristic feature of the NWs is through composition modulation. Using first principles calculations, we investigate the structural and electronic properties of core/shell modulated [111] zinc-blende InAs/InP NWs with different core/shell ratios and diameters (from 1.0 to 2.0 nm). Basic properties of these systems like the lattice parameter and the band gaps are seen to vary non-linearly with the core/shell ratio. The presence of an external InP shell is shown to improve the electronic mobility when compared with pure InAs NWs by eliminating the pinning of the Fermi level at InAs-derived surface states, while keeping the electron effective mass as low as in pure InAs NWs with similar diameters. We determine a type-I like band alignment, with a valence band offset depending on the core/shell ratio and a vanishing conduction band offset. We discuss the consequences of these results to the p-type conduction in the InAs core due to remote p-type doping at the InP shell region.
Hydrogen induced stabilization of meta-stable Mg-Ti
Authors: Jensen I. J. T. , Diplas S. , Løvvik O. M.
Published: March 2012

The hydrogenation of Mg0.8125Ti0.1875 was investigated by density functional calculations, using a model where Ti was segregated into nano-clusters. Introducing small amounts of hydrogen resulted in significant stabilization, with the mixing enthalpy (cohesive energy relative to standard state elements) becoming negative for hydrogen contents exceeding 0.07 H per metal. H prefers sites on the interface between Mg and Ti, with hydrogenation energies down to –115 kJ/(mol H2). Trapping of H on these very stable sites is proposed as an alternative explanation to why the reversibility of Mg-Ti thin films, which are initially meta-stable, can be preserved over many cycles of hydrogenation.
A sheath boundary condition for fast wave propagation near conducting surfaces
Authors: D’Ippolito D. A. , Myra J. R.
Published: March 2012

Radiofrequency (rf) waves can accelerate electrons into material boundaries, so that electron confinement requires rf sheath potentials that are significantly larger than the thermal Bohm sheath. The condition for rf sheaths to occur is that the rf electric field has a component E|| parallel to the equilibrium magnetic field. Thus, a proper treatment of rf wave propagation requires an accurate description of the geometry of the magnetic field and of the bounding surfaces, and a boundary condition (BC) that includes the effect on the waves of the electron-poor sheath. When the static magnetic field has a component at an angle to the sheath, the propagating fast wave (with E||=0) is coupled to a slow wave (with E||≠0) in order to satisfy the boundary condition at the metal wall, and the time-averaged sheath potential has a strong component from rectification of the rf sheath. In this brief communication, a previously derived sheath BC is reformulated to treat the coupling of the fast wave to the slow wave analytically, thereby greatly reducing the necessary numerical resolution required for calculation of fast wave propagation.
Current-driven domain wall motion in heterostructured ferromagnetic nanowires
Authors: Jang Youngman , Mascaro Mark D. , Beach G. S. D. , Ross C. A.
Published: March 2012

Micromagnetic modeling shows that the placement of non-magnetic conductive pads on a ferromagnetic wire affects the current-induced velocity of a domain wall (DW) in the wire and can act as a DW chirality filter. The pads shunt the current, causing a non-uniform spin current distribution inside the ferromagnetic wire and an Oersted field transverse to the wire. This suppresses Walker breakdown allowing higher current densities to be imposed before breakdown occurs. The transverse Oersted field pins the DW under some regimes of current density and pad geometry, selectively allowing transmission of DWs of only one chirality.
Ferromagnetic resonance in submicron amorphous wires
Authors: Kraus Luděk , Frait Zdeněk , Ababei Gabriel , Chayka Oleksandr , Chiriac Horia
Published: March 2012

Ferromagnetic resonance in glass-coated amorphous wires with the diameter of metallic core varying from 25 μm to 133 nm is investigated. The microwave frequencies of 49.1 and 69.7 GHz are used and static magnetic field is applied either parallel or perpendicular to the long wire axis. In agreement with theoretical predictions the resonance curves of submicron wires substantially differ from the curves of the bulk wires. Depending on the symmetry and intensity of microwave electric and magnetic fields in the sample vicinity the circumferential and/or dipolar resonance modes can be excited. In bulk wires the resonance fields of the two modes coincide. In submicron wires, however, their resonance fields differ, indicating the metallic character of the circumferential mode and the insulator character of the dipolar mode. In wires with diameters 717 and 869 nm radial standing spin wave resonances are observed in parallel field configuration. The experimental results for the parallel field configuration can be well explained by the rigorous theoretical model. From the fit of experimental data the exchange stiffness constant A = 8.2 10−12 J/m and perpendicular surface anisotropy constant Ks = 6 × 10−4 J/m2 are obtained. The resonance curves measured in the transversal field configuration can be well explained in the frame of the skin effect and quasistatic approximations for the bulk and submicron wires, respectively. In submicron wires, however, an additional resonance of unknown origin is observed at higher magnetic fields.
Strong terahertz absorption using SiO2/Al based metamaterial structures
Authors: Alves Fabio , Kearney Brian , Grbovic Dragoslav , Lavrik Nickolay V. , Karunasiri Gamani
Published: March 2012

Metamaterial absorbers with nearly 100% absorption in the terahertz (THz) spectral band have been designed and fabricated using a periodic array of aluminum (Al) squares and an Al ground plane separated by a thin silicon dioxide (SiO2) dielectric film. The entire structure is less than 1.6 mm thick making it suitable for the fabrication of microbolometers or bi-material sensors for THz imaging. Films with different dielectric layer thicknesses exhibited resonant absorption at 4.1, 4.2, and 4.5 THz with strengths of 98%, 95%, and 88%, respectively. The measured absorption spectra are in good agreement with simulations using finite element modeling.
Peculiar structure and tensile strength of WB4: nonstoichiometric origin
Authors: Gou Huiyang , Li Zhiping , Wang Li-Min , Lian Jie , Wang Yachun
Published: March 2012

Tungsten tetraboride (WB4) is experimentally considered as potentially superhard material and is therefore expected to have highly structural stability and enhanced resistance against plastic deformation and failure. The examinations of bond-deformation mechanism suggest a significantly soft bond-deformation pattern induced by ionic W-B bonding for nominal WB4 in experiments, largely responsible for the limitation of its strength and structural integrity. Computations on the structures and mechanical properties for WB4 show a novel thermodynamically favored MoB4-type phase with excellent mechanical properties and remarkable incompressibility along c direction. The illustrations of nonstoichiometry and x-ray diffraction spectra rationalize the experimental observation of nominal composition WB4 as defective tungsten borides (W1-xB3 (x<0.25) or WB4-x (x>0.25)). The results provide new insight into the real structural and mechanical properties of tungsten borides.
Observation of high pressure o-GeTe phase at ambient pressure in Si-Te-Ge glasses
Authors: Gunti Srinivasa Rao , Sundarrajan Asokan
Published: March 2012

Te-rich Si15Te85-xGex (1 ≤ x ≤ 11) glasses are found to exhibit an anomalous phase separations with germanium composition. The structural transformation of o-GeTe crystalline phase from o-GeTe with a = 11.76 Å, b = 16.59 Å, c = 17.44 Å, to high pressure o-GeTe with a new reduced lattice parameters a = 10.95 Å, b = 4.03 Å, c = 4.45 Å, is observed at Tc3 in the composition range 6 ≤ x ≤ 11. Raman studies support the possible existence of high pressure o-GeTe phase which is observed in X-ray diffraction experiments.
Feature Detection in Radio Astronomy using the Circle Hough Transform
Authors: Hollitt C. , Johnston-Hollitt M.
Published: March 2012

While automatic detection of point sources in astronomical images has experienced a great degree of success, less effort has been directed towards the detection of extended and low-surface-brightness features. At present, existing telescopes still rely on human expertise to reduce the raw data to usable images and then to analyse the images for non-pointlike objects. However, the next generation of radio telescopes will generate unprecedented volumes of data making manual data reduction and object extraction infeasible. Without developing new methods of automatic detection for extended and diffuse objects such as supernova remnants, bent-tailed galaxies, radio relics and halos, a wealth of scientifically important results will not be uncovered. In this paper we explore the response of the Circle Hough Transform to a representative sample of different extended circular or arc-like astronomical objects. We also examine the response of the Circle Hough Transform to input images containing noise alone and inputs including point sources.
Transverse Mixing of Simulated Piscicides in Small Montane Streams
Authors: Brown Peter J. , Ard Jenifer L. , Zale Alexander V.
Published: March 2012

Thorough mixing of piscicides into receiving waters is important for efficient and effective fish eradication. However, no guidance exists for the placement of drip stations with respect to mixing. Salt (NaCl) was used as a tracer to measure the mixing rates of center versus edge applications in riffle–pool, straight, and meandering sections of montane streams. The tracer was applied at either the center or the edge of a channel and measured with a conductivity meter across a downstream grid to determine the distances at which transverse mixing was complete. No advantage was accrued by applying piscicides in different types of channels because transverse mixing distance did not differ among them. However, mixing distance was significantly shorter at center applications. Chemicals entering a stream at the center of the channel mixed thoroughly within 10 stream widths, whereas chemicals entering a stream channel at the edge mixed thoroughly within 20 stream widths.
Licking and Liking: The Assessment of Hedonic Responses in Rodents
Authors: Dwyer Dominic M.
Published: March 2012

Affective processes are a key determinant of behaviour: At its simplest, liked stimuli are approached while disliked stimuli are avoided. Although assessing hedonic responses in nonverbal animals can be difficult, one relatively tractable approach relies on detailed analyses of rodents' consummatory behaviour. Rodents typically produce rhythmic sets of licks that can be grouped into clusters on the basis of the intervals between licks. The mean number of licks in a cluster (cluster size) is directly related to the concentration of palatable and unpalatable solutions. These relationships suggest that lick cluster size might be a useful index of an animal's hedonic reaction to the solution being consumed. I begin by reviewing studies of conditioned flavour preference and aversion that support the idea that lick cluster size can provide useful information about rats' hedonic reactions. I then describe how this methodology has been used to address previously intractable issues in the investigation of contrast effects as well as revealing an analogue of effort justification effects that, in humans, are commonly explained in terms of cognitive dissonance reduction. Finally, I consider how lick analysis might provide information about hedonic responses in animal models of human psychiatric disorders. In all these cases, how an animal did something was particularly informative about why it was doing it.
Influence of applied compressive stress on the hysteresis curves and magnetic domain structure of grain-oriented transverse Fe–3%Si steel
Authors: Perevertov O , Schäfer R
Published: March 2012

The influence of an applied compressive stress on the hysteresis curve and domain structure in conventional (1 1 0) [0 0 1] Fe–3%Si steel cut transverse to the rolling direction is studied. Quasistatic hysteresis loops under compressive stress up to 75 MPa were measured. The magnetic domains and magnetization processes were observed by longitudinal Kerr microscopy at different levels of stress. It is shown that the bulk hysteresis loop can be described with a good accuracy by the action of an effective field, which is the product of the stress and a function of magnetization. Domain observations have shown that the reasons for the effective field are demagnetizing fields due to the disappearance of supplementary domains along [0 1 0] and [1 0 0] at low fields and different domain systems in different grains at moderate fields. The latter are caused by differences in grain sensitivity to stress depending on the degree of misorientation. A decrease in the effective field above 1 T is connected with a transformation of all grains into the same domain system—the column pattern.
Zinc nitride films prepared by reactive RF magnetron sputtering of zinc in nitrogen containing atmosphere
Authors: Jiang Nanke , Georgiev Daniel G , Jayatissa Ahalapitiya H , Collins Robert W , Chen Jie , McCullen Erik
Published: March 2012

Zinc nitride films were deposited on glass or silicon substrates by reactive magnetron RF sputtering of zinc in N2–Ar ambient. The deposition conditions were optimized in terms of substrate temperature and N2/Ar sputtering gas ratio, and representative films were then studied by structure, optical and spectroscopy techniques, and electrical measurements. Spectroscopic ellipsometry and spectrophotometry measurements revealed that the material has a direct band gap close to 1.26 eV. Hall effect and resistivity measurements indicated n-type conductivity with a very high carrier concentration of about1021 cm−3, mobility of up to 90 cm2 V−1 s−1, and resistivity of ∼10−3 Ω cm. X-ray photoelectron spectroscopy spectra clearly showed the existence of not only Zn–N bonding but also of a fraction of N–N bonding configurations, together with an oxidized surface. According to energy-dispersive x-ray spectroscopy analysis, the as-deposited films were almost stoichiometric and contained only a small fraction of oxygen.
Cathode erosion in a high-pressure high-current arc: calculations for tungsten cathode in a free-burning argon arc
Authors: Nemchinsky Valerian
Published: March 2012

The motion of an evaporated atom of the cathode material in a near-cathode plasma is considered. It is shown that the evaporated atom is ionized almost instantly. The created ion, under the influence of a strong electric field existing in the cathode proximity, has a high probability of returning to the cathode. A small fraction of evaporated atoms are able to diffuse away from the cathode to the region where they are involved in plasma flow and lose their chance to return to the cathode. The fraction of the total evaporated atoms, which do not return to the cathode, the escape factor, determines the net erosion rate. In order to calculate this factor, the distributions of the plasma parameters in the near-cathode plasma were considered. Calculations showed that the escape factor is on the order of a few per cent. Using experimental data on the plasma and cathode temperatures, we calculated the net erosion rate for a free-burning 200 A argon arc with a thoriated tungsten cathode. The calculated erosion rate is close to 1 µg s−1, which is in agreement with available experimental data.
Preprojective algebras and MV polytopes
Authors: Baumann Pierre , Kamnitzer Joel
Published: March 2012

The purpose of this paper is to apply the theory of MV polytopes to the study of components of Lusztig’s nilpotent varieties. Along the way, we introduce reflection functors for modules over the non-deformed preprojective algebra of a quiver.
Burkholderia phytofirmansPsJN Acclimates Grapevine to Cold by Modulating Carbohydrate Metabolism
Authors: Fernandez Olivier , Theocharis Andreas , Bordiec Sophie , Feil Regina , Jacquens Lucile , Clément Christophe , Fontaine Florence , Barka Essaid Ait
Published: March 2012

Low temperatures damage many temperate crops, including grapevine, which, when exposed to chilling, can be affected by symptoms ranging from reduced yield up to complete infertility. We have previously demonstrated that Burkholderia phytofirmans PsJN, a plant growth-promoting rhizobacteria (PGPR) that colonizes grapevine, is able to reduce chilling-induced damage. We hypothesized that the induced tolerance may be explained at least partly by the impact of bacteria on grapevine photosynthesis or carbohydrate metabolism during cold acclimation. To investigate this hypothesis, we monitored herein the fluctuations of photosynthesis parameters (net photosynthesis [Pn], intercellular CO2concentration, stomatal conductances, ΦPSII, and total chlorophyll concentration), starch, soluble sugars (glucose, fructose, saccharose, mannose, raffinose, and maltose), and their precursors during 5 days of chilling exposure (4°C) on grapevine plantlets. Bacterization affects photosynthesis in a non–stomatal dependent pattern and reduced long-term impact of chilling on Pn. Furthermore, all studied carbohydrates known to be involved in cold stress tolerance accumulate in non-chilled bacterized plantlets, although some of them remained more concentrated in the latter after chilling exposure. Overall, our results suggest that modification of carbohydrate metabolism in bacterized grapevine plantlets may be one of the major effects by which this PGPR reduces chilling-induced damage.
First Report of Erysiphe knautiae (Erysiphales) on Lomelosia caucasica (Caucasian Pincushion Flower) in North America
Authors: Dugan Frank M.
Published: March 2012

Erysiphe knautiae (Erysiphales) is reported for the first time in North America on Lomelosia caucasica (Caucasian Pincushion Flower, Dipsacaceae).

Accepted for publication 7 January 2012. Published 27 February 2012.
Effects of Soybean Leaf and Plant Age on Susceptibility to Initiation of Infection by Phakopsora pachyrhizi
Authors: Bonde M. R. , Nester S. E. , Berner D. K.
Published: March 2012

To help resolve the question of relationship of soybean leaf and plant age to susceptibility to infection by Phakopsora pachyrhizi, we inoculated 50-day-old plants of cv. Williams 82 with a suspension at 3 × 103 urediniospores/ml, placed in growth chambers under a range of temperature conditions, and later examined for number of lesions. In addition, plants ranging in age from 20 days to 79 days were inoculated, placed in a greenhouse, and examined by leaf for number of lesions. Results showed that Williams 82 did not vary in susceptibility among leaves at different positions regardless of temperature, or among leaves at different positions (up to 11 trifoliolates) on individual plants ranging in age from 20 to 79 days at inoculation. However, on a per-plant basis, there was a gradual decrease in numbers of lesions as plants increased in age at inoculation. For example, whereas 37 lesions/cm2 leaf area were produced on 20-day-old plants, only 10 were produced on 79-day-old plants. Although the study does not rule out the possibility that there might be cultivar dependent differences in age response, it does strengthen the possibility that older plants are less susceptible, and that the increase in disease observed in the field during fall months may be due to an increase in favorability of the environment for disease or increase in inoculum pressure.

Accepted for publication 23 November 2011. Published 27 February 2012.
Modeling Sporulation of Fusicladium carpophilum on Nectarine Twig Lesions: Relative Humidity and Temperature Effects
Authors: Lalancette N. , McFarland K. A. , Burnett A. L.
Published: March 2012

The production of conidia by Fusicladium carpophilum on twig lesions was quantitatively modeled as a function of temperature and duration of high relative humidity. During peak sporulation periods in 2007, 2008, and 2009, 1-year-old twigs bearing abundant overwintering lesions were removed from a heavily infected ‘Redgold’ nectarine orchard, placed in trays at high relative humidity (>95%), and incubated at eight constant temperatures for seven durations, resulting in a factorial design of 56 treatment combinations. Conidia numbers were estimated with a hemacytometer. Results from a six-stage modeling process indicated that, at any given temperature, spore production during high relative humidity periods increased in a monomolecular- to Gompertz-like pattern. The Richards model, with shape parameters of 0.79 to 0.90, was found to provide the best overall fit. When the asymptote and rate parameters were derived as functions of temperature using Gaussian and quadratic models, respectively, the duration of high relative humidity and temperature described 90 to 94% of the variation in conidia production. Predictions of the final models were highly correlated with observed levels of sporulation (r > 0.94; P < 0.0001), indicating an excellent fit to the data. The optimum temperature for sporulation, based on fitting a Gaussian model to the maximum sporulation levels at each temperature, was 17.9 to 20.2°C, with an overall average of 18.8°C. The derived models give a quantitative description of sporulation by F. carpophilum and may have potential use in simulators and forecasting systems.
Chaperone–usher pathways: diversity and pilus assembly mechanism
Authors: Busch Andreas , Waksman Gabriel
Published: March 2012

Up to eight different types of secretion systems, and several more subtypes, have been described in Gram-negative bacteria. Here, we focus on the diversity and assembly mechanism of one of the best-studied secretion systems, the widespread chaperone–usher pathway known to assemble and secrete adhesive surface structures, called pili or fimbriae, which play essential roles in targeting bacterial pathogens to the host.
Type V secretion: mechanism(s) of autotransport through the bacterial outer membrane
Authors: Leo Jack C. , Grin Iwan , Linke Dirk
Published: March 2012

Autotransport in Gram-negative bacteria denotes the ability of surface-localized proteins to cross the outer membrane (OM) autonomously. Autotransporters perform this task with the help of a β-barrel transmembrane domain localized in the OM. Different classes of autotransporters have been investigated in detail in recent years; classical monomeric but also trimeric autotransporters comprise many important bacterial virulence factors. So do the two-partner secretion systems, which are a special case as the transported protein resides on a different polypeptide chain than the transporter. Despite the great interest in these proteins, the exact mechanism of the transport process remains elusive. Moreover, different periplasmic and OM factors have been identified that play a role in the translocation, making the term ‘autotransport’ debatable. In this review, we compile the wealth of details known on the mechanism of single autotransporters from different classes and organisms, and put them into a bigger perspective. We also discuss recently discovered or rediscovered classes of autotransporters.
Obesity Is a Marker of Reduction in QoL and Disability
Authors: Sirtori Anna , Brunani Amelia , Villa Valentina , Berselli Maria Elisa , Croci Marina , Leonardi Matilde , Raggi Alberto
Published: March 2012

The purpose of this paper is to verify the association between outcome measures of health-related quality of life (HRQoL) and disability, BMI, gender, and age. Adult obese patients were clustered using HRQoL (IWQoL-Lite) and disability (WHO-DAS II) scores into three groups: mild, moderate, and high. One-way ANOVA with Bonferroni post hoc test was used to evaluate differences in age and BMI between subjects from different clusters, contingency coefficient to test the relationship between cluster groups and gender. In total, 117 patients were enrolled: subjects with higher disability and HRQoL decrement were older and had higher BMI. Women were more likely to present moderate disability and reduction in HRQoL, while men more likely presented mild disability and HRQoL reduction. Our data further confirm the connection between disability and HRQoL, high BMI and older age. These data obtained with outcomes measures might better address rehabilitation programs.
Visualization of Chronic Myocardial Infarction Using the Intravascular Contrast Agent MS-325 (Gadofosveset) in Patients
Authors: Thouet Thomas , Schnackenburg Bernhard , Kokocinski Thomas , Fleck Eckart , Nagel Eike , Kelle Sebastian
Published: March 2012

Aims. The aim of this study was to evaluate the potential of visualizing chronic myocardial infarction in patients using the intravascular CA MS-325 (gadofosveset, EPIX Pharmaceuticals, Mass, USA).Methods. Nine patients were enrolled in a clinical phase II multicenter trial for MRCA and perfusion imaging using MS-325. They had objective evidence of chronic myocardial infarction as visualized by previously performed late gadolinium (Gd) enhancement imaging (LGE) with a conventional extracellular Gd-DTPA CA (Magnevist, Bayer Healthcare, Germany, 0.2 mmol/kg/body weight) serving as reference standard. A prepulse-optimized LGE study was performed immediately and at several time points after injection of MS-325 (0.05 mmol/kg/body weight). The number and localization of segments demonstrating LGE with MS-325 as well as signal intensities were compared with the reference standard (Gd-DTPA).Results. Using MS-325, LGE could be detected at every time point in all 9 patients. The accuracy of LGE with MS-325 as compared to LGE with Gd-DTPA was highest minutes after contrast injection, resulting in a sensitivity of 84% with a specificity of 98%.Conclusion. The intravascular CA MS-325 has the potential to visualize chronic myocardial infarction. However, in comparison with Gd-DTPA, the transmural extent and the number of segments are smaller.
Serial MRI Features of Canine GM1 Gangliosidosis: A Possible Imaging Biomarker for Diagnosis and Progression of the Disease
Authors: Hasegawa Daisuke , Yamato Osamu , Nakamoto Yuya , Ozawa Tsuyoshi , Yabuki Akira , Itamoto Kazuhito , Kuwabara Takayuki , Fujita Michio , Takahashi Kimimasa , Mizoguchi Shunta , Orima Hiromitsu
Published: March 2012

GM1 gangliosidosis is a fatal neurodegenerative lysosomal storage disease caused by an autosomal recessively inherited deficiency ofβ-galactosidase activity. Effective therapies need to be developed to treat the disease. In Shiba Inu dogs, one of the canine GM1 gangliosidosis models, neurological signs of the disease, including ataxia, start at approximately 5 months of age and progress until the terminal stage at 12 to 15 months of age. In the present study, serial MR images were taken of an affected dog from a model colony of GM1 gangliosidosis and 4 sporadic clinical cases demonstrating the same mutation in order to characterize the MRI features of this canine GM1 gangliosidosis. By 2 months of age at the latest and persisting until the terminal stage of the disease, the MR findings consistently displayed diffuse hyperintensity in the white matter of the entire cerebrum on T2-weighted images. In addition, brain atrophy manifested at 9 months of age and progressed thereafter. Although a definitive diagnosis depends on biochemical and genetic analyses, these MR characteristics could serve as a diagnostic marker in suspect animals with or without neurological signs. Furthermore, serial changes in MR images could be used as a biomarker to noninvasively monitor the efficacy of newly developed therapeutic strategies.
Photoassisted Degradation of a Herbicide Derivative, Dinoseb, in Aqueous Suspension of Titania
Authors: Mir Niyaz A. , Haque Malik M. , Khan Abuzar , Muneer Mohd. , Boxall Colin
Published: March 2012

The titanium dioxide (TiO2) photoassisted degradation of herbicide dinoseb has been examined in aqueous suspensions under UV light irradiation. The degradation kinetics were studied under various conditions such as substrate concentration, type of catalyst, catalyst dosage, pH, and light intensity as well as in presence of electron acceptors such as hydrogen peroxide, potassium bromate, and potassium persulphate under continuous air purging, and the degradation rates were found to be strongly influenced by these parameters. The Degussa P25 was found to be more efficient photocatalyst as compared to other photocatalysts tested. Dinoseb was found to degrade efficiently in acidic pH and all the electron acceptors studied enhanced the degradation rate. The results manifested that the photocatalysis of dinoseb followed pseudo-first-order kinetics. A qualitative study of the degradation products generated during the process was performed by GC-MS, and a degradation mechanism was proposed.
Antinociceptive Effect of Rat D-Serine Racemase Inhibitors, L-Serine-O-Sulfate, and L-Erythro-3-Hydroxyaspartate in an Arthritic Pain Model
Authors: Laurido Claudio , Hernández Alejandro , Pelissier Teresa , Constandil Luis
Published: March 2012

N-methyl-D-aspartic acid receptor (NMDAr) activation requires the presence of D-serine, synthesized from L-serine by a pyridoxal 5′-phosphate-dependent serine racemase (SR). D-serine levels can be lowered by inhibiting the racemization of L-serine. L-serine-O-sulfate (LSOS) and L-erythro-3-hydroxyaspartate (LEHA), among others, have proven to be effective in reducing the D-serine levels in culture cells. It is tempting then to try these compounds in their effectiveness to decrease nociceptive levels in rat arthritic pain. We measured the C-reflex paradigm and wind-up potentiation in the presence of intrathecally injected LSOS (100 μg/10 μL) and LEHA (100 μg/10 μL) in normal and monoarthritic rats. Both compounds decreased the wind-up activity in normal and monoarthritic rats. Accordingly, all the antinociceptive effects were abolished when 300 μg/10 μL of D-serine were injected intrathecally. Since noin vivoresults have been presented so far, this constitutes the first evidence that SR inhibitions lower the D-serine levels, thus decreasing the NMDAr activity and the consequent development and maintenance of chronic pain.
Efficacy and Safety of Immunotherapy with Interferon-Gamma in the Management of Chronic Sulfur Mustard-Induced Cutaneous Complications: Comparison with Topical Betamethasone 1%
Authors: Panahi Yunes , Sahebkar Amirhossein , Davoudi Seyyed Masoud , Amiri Mojtaba , Beiraghdar Fatemeh
Published: March 2012

The present trial investigated the efficacy of immunotherapy with interferon-gamma (IFN-γ) in the treatment of sulfur mustard (SM)-induced chronic skin complications. Forty subjects who were suffering from chronic skin complications of SM and were diagnosed to have severe atopic dermatitis, were assigned to IFN-γ (50 μg/m2) subcutaneously three times per week (n=20) or betamethasone valerate topical cream 0.1% (n=20) every night for 30 days. Extent and intensity of cutaneous complications was evaluated using scoring atopic dermatitis (SCORAD) index, and quality of life using dermatology life quality index (DLQI) at baseline and at the end of trial. SCORAD-A and SCORAD-B scores were significantly decreased in both IFN-γ and betamethasone. However, SCORAD-C score was decreased only in the IFN-γ group. There were significant reductions in overall as well as objective SCORAD scores in both groups. As for the magnitude of changes, treatment with IFN-γ was associated with greater reductions in overall, objective and segmented SCORAD scores compared to betamethasone. DLQI reduction was found to be significantly greater in the IFN-γ group. Promising improvements in quality life and clinical symptoms that was observed in the present study suggest the application of IFN-γ as an effective therapy for the management of SM-induced chronic skin complications.
Prevalence of Isolated Atrial Amyloidosis in Young Patients Affected by Congestive Heart Failure
Authors: Millucci Lia , Ghezzi Lorenzo , Bernardini Giulia , Braconi Daniela , Tanganelli Piero , Santucci Annalisa
Published: March 2012

Atrial natriuretic peptide (ANP), whose amyloid is responsible of isolated atrial amyloidosis (IAA), is known to play an important role in the pathophysiology of congestive heart failure (CHF). We provide here the microscopic examination of atrial biopsies from 36 young (mean 40 years) CHF patients distinguished in idiopathic dilated cardiomyopathy (DC) affected and hypertrophic Cardiomyopathy (HC) affected, endorsing the presumptive association of early CHF with IAA. We utilized a multiple method, using Congo red (CR) staining, CR fluorescence (CRF), and immunohistochemistry to assess the presence of IAA in CHF. Immunostaining showed a moderate deposition of IAA in the atrium surrounding working myocardium with small intracellular deposits. Our findings suggest a monitoring of young CHF cases for the development of IAA. Our study also demonstrated how the concurrent use of immunohistochemistry, CR, and CRF may greatly enhance the detection of low-grade amyloid deposits.
Variation of Biophysical Parameters of the Skin with Age, Gender, and Body Region
Authors: Firooz Alireza , Sadr Bardia , Babakoohi Shahab , Sarraf-Yazdy Maryam , Fanian Ferial , Kazerouni-Timsar Ali , Nassiri-Kashani Mansour , Naghizadeh Mohammad Mehdi , Dowlati Yahya
Published: March 2012

Background. Understanding the physiological, chemical, and biophysical characteristics of the skin helps us to arrange a proper approach to the management of skin diseases.Objective. The aim of this study was to measure 6 biophysical characteristics of normal skin (sebum content, hydration, transepidermal water loss (TEWL), erythema index, melanin index, and elasticity) in a normal population and assess the effect of sex, age, and body location on them.Methods. Fifty healthy volunteers in 5 age groups (5 males and females in each) were enrolled in this study. A multifunctional skin physiology monitor (Courage & Khazaka electronic GmbH, Germany) was used to measure skin sebum content, hydration, TEWL, erythema index, melanin index, and elasticity in 8 different locations of the body.Results. There were significant differences between the hydration, melanin index, and elasticity of different age groups. Regarding the locations, forehead had the highest melanin index, where as palm had the lowest value. The mean values of erythema index and melanin index and TEWL were significantly higher in males and anatomic location was a significant independent factor for all of 6 measured parameters.Conclusion. Several biophysical properties of the skin vary among different gender, age groups, and body locations.
Psychoeducational Characteristics of Children with Hypohidrotic Ectodermal Dysplasia
Authors: Maxim Rolanda A. , Zinner Samuel H. , Matsuo Hisako , Prosser Theresa M. , Fete Mary , Leet Terry L. , Fete Timothy J.
Published: March 2012

Objective. Hypohidrotic ectodermal dysplasia (HED) is an X-linked hereditary disorder characterized by hypohidrosis, hypotrichosis, and anomalous dentition. Estimates of up to 50% of affected children having intellectual disability are controversial.Method. In a cross-sectional study, 45 youth with HED (77% males, mean age 9.75 years) and 59 matched unaffected controls (70% males, mean age 9.79 years) were administered the Kaufman Brief Intelligence Test and the Kaufman Test of Educational Achievement, and their parents completed standardized neurodevelopmental and behavioral measures, educational, and health-related information regarding their child, as well as standardized and nonstandardized data regarding socioeconomic information for their family.Results. There were no statistically significant differences between the two groups in intelligence quotient composite and educational achievement scores, suggesting absence of learning disability in either group. No gender differences within or between groups were found on any performance measures. Among affected youth, parental education level correlated positively with (1) cognitive vocabulary scores and cognitive composite scores; (2) educational achievement for mathematics, reading, and composite scores.Conclusion. Youth affected with HED and unaffected matched peers have similar profiles on standardized measures of cognition, educational achievement, and adaptive functioning although children with HED may be at increased risk for ADHD.
Enhanced MRI and MRI-Guided Interventional Procedures in Women with Asymptomatic Silicone-Injected Breasts
Authors: Cheung Yun-Chung , Chen Shin-Chih , Lo Yung-Feng
Published: March 2012

Asymptomatic women who have received silicone injection for breast augmentation have a risk of underestimating breast cancer by palpation, mammography, or breast sonography. Enhanced breast MRI is sensitive to display certain nonspecific enhanced lesions or suspicious lesions. Such nonspecific MRI-detected lesions could be managed by American College Radiology BI-RADS lexicon and selectively with MRI-guided techniques biopsy to prevent unnecessary surgery.
Vascular Function and Handgrip Strength in Rheumatoid Arthritis Patients
Authors: Alomari Mahmoud A. , Keewan Esraa F. , Shammaa Rania A. , Alawneh Khaldoon , Khatib Said Y. , Welsch Michael A.
Published: March 2012

Objective. To examine the relationship of handgrip strength with forearm blood flow (BF) and vascular resistance (VR) in rheumatoid arthritis (RA) patients.Methods. Forearm BF at rest (RBF) and after upper arm occlusion (RHBF), and handgrip strength were examined in 78 individuals (RA=42and controls (CT)=36). Subsequently, VR at rest (RVR) and after occlusion (RHVR) were calculated.Results. The patients’ RBF (P=0.02) and RHBF (P=0.0001) were less, whereas RVR (P=0.002) and RHVR (P=0.0001) were greater as compared to the CTs. Similarly, handgrip strength was lower in the RAs (P=0.0001). Finally, handgrip strength was directly associated with RBF (r=0.43;P=0.0001), and RHBF (r=0.5;P=0.0001), and inversely related to RVR (r=-0.3;P=0.009) and RHVR (r=-0.3;P=0.007).Conclusion. The present study uniquely identifies an association between regional measures of forearm blood flow and handgrip strength in patients and healthy control. In addition, this study confirms the presence of vascular and muscle dysfunction in patients with rheumatoid arthritis, as evidenced by lower forearm blood flow indices, at rest and following occlusion, and lower handgrip strength as compared to healthy individuals.
Effects ofCO2Enrichment on Growth and Development ofImpatiens hawkeri
Authors: Zhang Fan-Fan , Wang Yan-Li , Huang Zhi-Zhe , Zhu Xiao-Chen , Zhang Feng-Jiao , Chen Fa-Di , Fang Wei-Min , Teng Nian-Jun
Published: March 2012

The effects of CO2enrichment on growth and development ofImpatiens hawkeri, an important greenhouse flower, were investigated for the purpose of providing scientific basis for CO2enrichment to this species in greenhouse. The plants were grown in CO2-controlled growth chambers with 380 (the control) and 760 (CO2enrichment) μmol⋅mol-1, respectively. The changes in morphology, physiology, biochemistry, and leaf ultrastructure ofImpatienswere examined. Results showed that CO2enrichment increased flower number and relative leaf area compared with the control. In addition, CO2enrichment significantly enhanced photosynthetic rate, contents of soluble sugars and starch, activities of peroxidase (POD), superoxide dismutase (SOD), and ascorbate peroxidase (APX), but reduced chlorophyll content and malondialdehyde (MDA) content. Furthermore, significant changes in chloroplast ultrastructure were observed at CO2enrichment: an increased number of starch grains with an expanded size, and an increased ratio of stroma thylakoid to grana thylakoid. These results suggest that CO2enrichment had positive effects onImpatiens, that is, it can improve the visual value, promote growth and development, and enhance antioxidant capacity.
Uranium in the Surrounding of San Marcos-Sacramento River Environment (Chihuahua, Mexico)
Authors: Rentería-Villalobos Marusia , Cortés Manuel Reyes , Mantero Juan , Manjón Guillermo , García-Tenorio Rafael , Herrera Eduardo , Montero-Cabrera Maria Elena
Published: March 2012

The main interest of this study is to assess whether uranium deposits located in the San Marcos outcrops (NW of Chihuahua City, Mexico) could be considered as a source of U-isotopes in its surrounding environment. Uranium activity concentrations were determined in biota, ground, and surface water by either alpha or liquid scintillation spectrometries. Major ions were analyzed by ICP-OES in surface water and its suspended matter. For determining uranium activity in biota, samples were divided in parts. The results have shown a possible lixiviation and infiltration of uranium from geological substrate into the ground and surface water, and consequently, a transfer to biota. Calculated annual effective doses by ingestion suggest that U-isotopes in biota could not negligibly contribute to the neighboring population dose. By all these considerations, it is concluded that in this zone there is natural enhancement of uranium in all environmental samples analyzed in the present work.