bluuebunny/crossref_metadata_2025 huggingface dataset:
Electron spin resonance features of the Ge Pb1 dangling bond defect in condensation-grown (100)Si/SiO2/Si1−xGex/SiO2 heterostructures
Authors: Somers P. , Stesmans A. , Souriau L. , Afanas’ev V. V.
Published: October 2012

A multi-frequency electron spin resonance (ESR) study has been carried out the Ge Pb1 dangling bond (DB)-type interface defect in SiO2/GexSi1−x/SiO2/(100)Si heterostructures of different Ge fraction manufactured by the condensation technique. The notable absence of Si Pb-type centers enables unobscured spectral analysis as function of magnetic field angle, reassured by coinciding multi-frequency ESR data. The center features monoclinic-I (C2v) symmetry with principal g values g1 = 2.0338 ± 0.0003, g2 = 2.0386 ± 0.0006, g3 = 2.0054, with the lowest value, g3, axis 24 ± 2° off a 〈111〉 direction towards the [100] interface normal n. The defect appearance shows a systematic variation as function of x, reaching maximum densities of ∼6.8 × 1012 cm−2 per Si/SiO2 interface for x ∼ 0.7, to disappear for x outside the ]0.45–0.87[ range. The ESR signal width is dominated by inhomogeneous broadening arising from strain-induced Gaussian spread in g, resulting in frequency (ν)-dependent peak-to-peak broadening of ΔBppSB/ν = 0.62 G/GHz and 1.13 G/GHz for the applied magnetic field B//g3 principal axis and B//n, respectively. Compared to the familiar Si Pb-type interface defects in (100)Si/SiO2, the enhanced ν-dependent broadening scales with the spin-orbit coupling constant ratio λ(Ge)/λ(Si). The natural inhomogeneous broadening due to unresolved 73Ge hyperfine interaction is found to be below ∼1.56 G, the inferred residual (ν→0) width. The core of the defect, previously depicted as a Ge Pb1-type center, concerns an asymmetrically back bonded trivalent Ge atom where the total of all data would suggest a back bond arrangement involving two Ge and one Si atoms and/or a strained bond. Initial studies show the defect to exhibit reversal hydrogen passivation/depassivation kinetics, where defects can be substantially, yet only partially, ESR-inactivated by heating in H2. The properties and nature of the center are discussed within the context of the their inherent incorporation as interface mismatch centers, where assessing the defect’s nature and modalities of occurrence may provide a link to unraveling the role of point defects in adapting interfacial mismatch.
Spin dynamics of S = 1/2 Heisenberg chains with a staggered transverse field: electron spin resonance studies (Review Article)
Authors: Zvyagin S. A.
Published: October 2012

This article is a review of the recent achievements in experimental studies of magnetic excitations in the copper pyrimidine dinitrate [PM–Cu(NO3)2(H2O)2]n (PM = pyrimidine), an S = 1/2 antiferromagnetic chain material with an alternating g-tensor and the Dzyaloshinskii–Moriya interaction, by means of high-field electron spin resonance (ESR). Due to this alternation, in the 1D critical regime this material exhibits a field-induced gap. The excitation spectrum is formed by solitons and their bound states, breathers, and can be effectively described using the sine-Gordon model. With increasing temperature, the soliton-breather regime can be suppressed, resulting in a substantial evolution of ESR parameters. These changes can be described using a new theoretical concept recently proposed for S = 1/2 AF chains with a staggered transverse field. High magnetic field induces a transition into the spin-polarized state with the excitation spectrum formed by magnons. Nonmonotonous behavior of the field-induced gap is observed in vicinity of the saturation field. Experimental data are compared with results of existing theoretical approaches, revealing excellent agreement with predictions.
Temperature dependences of surface magnetoelastic constants of ultrathin Fe/GaAs (001) films
Authors: Żuberek R. , Nesteruk K. , Fronc K. , Piechota S. , Szymczak H.
Published: October 2012

The magnetoelastic constants of epitaxial iron films prepared by dc magnetron sputtering on single crystal GaAs (001) substrate in argon atmosphere and covered with a protective Si layer have been investigated in the temperature range 10–300 K by means of the strain modulated ferromagnetic resonance. It has been shown that the magnetoelastic constants strongly depend on the thickness of the film. The surface components of the magnetoelastic constants have been determined and analyzed within the Néel and dipolar models. The proposed analysis of experimental data gives chance for deeper insight into mechanisms responsible for magnetostriction of iron thin films.
Magneto-optical study of holmium iron garnet Ho3Fe5O12
Authors: Kalashnikova A. M. , Pavlov V. V. , Kimel A. V. , Kirilyuk A. , Rasing Th. , Pisarev R. V.
Published: October 2012

Bulk holmium iron garnet Ho3Fe5O12 is a cubic ferrimagnet with Curie temperature TC = 567 K and magnetization compensation point in the range 130–140 K. The magneto-optical data are presented for a holmium iron garnet Ho3Fe5O12 film, ∼10 μm thick, epitaxially grown on a (111)-type gadolinium-gallium garnet Gd3Ga5O12 substrate. A specific feature of this structure is that the parameters of the bulk material, from which the film was grown, closely match the substrate ones. The temperature and field dependences of Faraday rotation as well as the temperature dependence of the domain structure in zero field were investigated. The compensation point of the structure was found to be Tcomp = 127 K. It was shown that the temperature dependence of the characteristic size of domain structure diverges at this point. Based on the obtained results we established that the magnetic anisotropy of the material is determined by both uniaxial and cubic contributions, each characterized by different temperature dependence. A complex shape of hysteresis loops and sharp changes of the domain pattern with temperature indicate the presence of collinear–noncollinear phase transitions. Study of the optical second harmonic generation was carried out using 100 fs laser pulses with central photon energy E = 1.55 eV. The electric dipole contribution (both crystallographic and magnetic) to the second harmonic generation was observed with high reliability despite a small mismatch of the film and substrate parameters.
Asymptotic analysis of the Boltzmann equation for dark matter relics
Authors: Bender Carl M. , Sarkar Sarben
Published: October 2012

This paper presents an asymptotic analysis of the Boltzmann equations (Riccati differential equations) that describe the physics of thermal dark-matter-relic abundances. Two different asymptotic techniques are used, boundary-layer theory, which makes use of asymptotic matching, and the delta expansion, which is a powerful technique for solving nonlinear differential equations. Two different Boltzmann equations are considered. The first is derived from general relativistic considerations and the second arises in dilatonic string cosmology. The global asymptotic analysis presented here is used to find the long-time behavior of the solutions to these equations. In the first case, the nature of the so-called freeze-out region and the post-freeze-out behavior is explored. In the second case, the effect of the dilaton on cold dark-matter abundances is calculated and it is shown that there is a large-time power-law fall off of the dark-matter abundance.
CO2 sequestration in a radial Hele-Shaw cell via an interfacial chemical reaction
Authors: White Andrew R. , Ward Thomas
Published: October 2012

In this manuscript, experimental data for the displacement of a finite volume of aqueous Ca(OH)2 using CO2 gas in a radial Hele-Shaw cell will be presented. This chemical reaction is known to generate CaCO3 precipitate along the gas-liquid interface and we seek to understand the influence of the reactive process on fluid displacement. The reactive experiment is compared with the non-reactive case to determine if there are any measurable differences between the two in the range of parameters: CO2 pressures (1%–10% of an atmosphere measured in gage pressure), liquid volumes (either 50 or 70 μl), and Ca(OH)2 concentrations (0, 10, or 20 mM) studied. Analysis is performed by measuring the displacing fluid area Agas and total fluid area Atot to determine several quantities (gas expansion rate, quasi-equilibrium film rate and value, and presence of fingering instability) used to distinguish the experiments. In general there appears to be little effect of the chemical reaction on most of the measured quantities.
Angle-resolved environmental X-ray photoelectron spectroscopy: A new laboratory setup for photoemission studies at pressures up to 0.4 Torr
Authors: Mangolini F. , Åhlund J. , Wabiszewski G. E. , Adiga V. P. , Egberts P. , Streller F. , Backlund K. , Karlsson P. G. , Wannberg B. , Carpick R. W.
Published: October 2012

The paper presents the development and demonstrates the capabilities of a new laboratory-based environmental X-ray photoelectron spectroscopy system incorporating an electrostatic lens and able to acquire spectra up to 0.4 Torr. The incorporation of a two-dimensional detector provides imaging capabilities and allows the acquisition of angle-resolved data in parallel mode over an angular range of 14° without tilting the sample. The sensitivity and energy resolution of the spectrometer have been investigated by analyzing a standard Ag foil both under high vacuum (10−8 Torr) conditions and at elevated pressures of N2 (0.4 Torr). The possibility of acquiring angle-resolved data at different pressures has been demonstrated by analyzing a silicon/silicon dioxide (Si/SiO2) sample. The collected angle-resolved spectra could be effectively used for the determination of the thickness of the native silicon oxide layer.
The tracking control system of the VLT Survey Telescope
Authors: Schipani P. , Arcidiacono C. , Argomedo J. , Dall’Ora M. , D’Orsi S. , Farinato J. , Magrin D. , Marty L. , Ragazzoni R. , Umbriaco G.
Published: October 2012

The VLT survey telescope is the latest telescope installed at European Southern Observatory's Paranal observatory that is considered one of the best sites for optical astronomy for the excellent seeing conditions. The exceptional quality of the site imposes tight requirements for the telescope tracking system that shall perform very well to fully exploit the extreme sharpness of the Chilean sky. We describe the specific solutions adopted for pointing, servo and guiding systems and the results obtained during the commissioning of the telescope. The hardware implementation relies on industry components and the control solutions privilege both the performance and the future maintainability of the system.
Polarization screening in polymer ferroelectric films: Uncommon bulk mechanism
Authors: Mikheev E. , Stolichnov I. , Tagantsev A. K. , Setter N.
Published: October 2012

Charge compensation at the interface is a fundamental phenomenon determining the operation conditions of thin-film devices incorporating ferroelectrics. The underlying mechanisms have been thoroughly addressed in perovskite ferroelectrics where the charge compensation originates from injection through the interface-adjacent layer. Here, we demonstrate that polarization screening in the polymer ferroelectric polyvinylidene fluoride-trifluoroethylene (P(VDF-TrFE)) films can be dominated by charge injection through the bulk, unlike ferroelectric oxides. The experimental evidence relies on polarization imprint under applied field and time-dependence of the dielectric constant. A linearized electrostatic model correctly accounts for the observed trends and links their occurrence to the unique properties of P(VDF-TrFE).
The vibrationally mediated photodissociation of Cl2
Authors: Campbell E. K. , Alekseyev A. B. , Balint-Kurti G. G. , Brouard M. , Brown Alex , Buenker R. J. , Johnsen A. J. , Kokh D. B. , Lucas S. , Winter B.
Published: October 2012

The photodissociation of vibrationally excited Cl2(v = 1) has been investigated experimentally using the velocity mapped ion imaging technique. The experimental measurements presented here are compared with the results of time-dependent wavepacket calculations performed on a set of ab initio potential energy curves. The high level calculations allow prediction of all the dynamical information regarding the dissociation, including electronic polarization effects. Using a combination of theory and experiment it was found that there was negligible cooling of the vibrational degree of freedom of the parent molecule in the molecular beam. The results presented are compared with those following the photodissociation of Cl2(v = 0). Although the same electronic states are found to be important for Cl2(v = 1) as for Cl2(v = 0), significant differences were found regarding many of the observables. The overall level of agreement between theory and experiment was found to be reasonable and confirms previous assignments of the photodissociation mechanism.
Compact scanning tunneling microscope for spin polarization measurements
Authors: Kim Seong Heon , Lozanne Alex de
Published: October 2012

We present a design for a scanning tunneling microscope that operates in ultrahigh vacuum down to liquid helium temperatures in magnetic fields up to 8 T. The main design philosophy is to keep everything compact in order to minimize the consumption of cryogens for initial cool-down and for extended operation. In order to achieve this, new ideas were implemented in the design of the microscope body, dewars, vacuum chamber, manipulators, support frame, and vibration isolation. After a brief description of these designs, the results of initial tests are presented.
Micro-manipulation using rotational fluid flows induced by remote magnetic micro-manipulators
Authors: Ye Zhou , Diller Eric , Sitti Metin
Published: October 2012

We present a non-contact manipulation method for micron scale objects using locally induced rotational fluid flows created by groups of untethered magnetic micro-manipulators. The magnetic micro-manipulators are rotated in a viscous fluid by an externally generated magnetic field to create rotational flows, which act to move micro-objects in the flow region. One single spherical micro-manipulator is used to manipulate one object at a time, while an array of micro-manipulators spin in synchrony on a surface patterned with magnetic micro-docks to create reconfigurable fluidic channels for simultaneous transportation of multiple objects. The induced rotational flow field and the resulting hydrodynamic forces on the micro-objects are studied using both finite element solutions and analytical models from previous studies. These results are compared with experiment to determine manipulation characteristics for the complex flows. Due to its untethered and non-contact operation, this micro-manipulation method could be used to quickly move fragile or non-fragile micro-objects in inaccessible or enclosed spaces such as in lab-on-a-chip devices.
The Lorentzian oscillator group as a geodesic orbit space
Authors: Batat W. , Gadea P. M. , Oubiña J. A.
Published: October 2012

We prove that the four-dimensional oscillator group Os, endowed with any of its usual left-invariant Lorentzian metrics, is a Lorentzian geodesic (so, in particular, null-geodesic) orbit space with some of its homogeneous descriptions corresponding to certain homogeneous Lorentzian structures. Each time that Os is endowed with a suitable metric and an appropriate homogeneous Lorentzian structure, it is a candidate for constructing solutions in d-dimensional supergravity with at least 24 of the 32 possible supersymmetries.
Phase field model of domain dynamics in micron scale, ultrathin ferroelectric films: Application for multiferroic bismuth ferrite
Authors: Ashraf Khalid , Salahuddin Sayeef
Published: October 2012

In this work, we report a massively parallel and time domain implementation of the 3D phase field model that can reach beyond micron scale and consider for arbitrary electrical and mechanical boundary conditions. The first part of the paper describes the theory and the numerical implementation of the model. A mixed-mode approach of finite difference and finite element grid has been used for calculating the nonlocal electrostatic and elastic interactions respectively. All the local and non-local interactions are shown to scale linearly up to thousands of processors. This massive paralleling allows to compare our results directly with experiments at the same length scales where the experiments themselves are performed. The second part of the paper presents results of ferroelectric domain switching in devices based on the multi-ferroic BiFeO3. We have particularly emphasized the importance of charge driven domain growth and the effect of electrical boundary conditions that explain the temporal evolution of ferroelectric domains observed in recent experiments. We also predict a mechanism of controlling domain size in the multi-domain ferroelectric switching that could be useful for practical applications.
Melt fragility of near-intermetallic composition
Authors: Wang Xinzhu , Bian Xiufang , Song Kaikai , Zhao Xiaolin , Bai Yanwen
Published: October 2012

The dynamic viscosities of In-Bi and Ag-Yb alloy systems are measured by the torsional oscillation viscometer and the corresponding melt fragilities (M) are calculated from the temperature dependence of viscosities fitted by the Arrhenius equation. It was found that the melt fragility of the intermetallics is larger than that of the alloys with near-intermetallic compositions, but is smaller than that of the alloys with near-intermetallic compositions with a peritectic reaction. From the thermodynamics and kinetics points of view, the origins for the compositions near intermetallics as potential hosts of glass formers were well demonstrated. Our study confirms the universality of melt fragility and gives implications on the physical mechanisms for the glass forming alloys.
Enhanced piezoelectric and antiferroelectric properties of high-TC perovskite of Zr-substituted Bi(Mg1/2Ti1/2)O3-PbTiO3
Authors: Chen Jun , Li Jianyong , Fan Longlong , Zou Ning , Ji Pengfei , Liu Laijun , Fang Liang , Kang Huajun , Xing Xianran
Published: October 2012

Bi(Mg1/2Ti1/2)O3-PbTiO3 is a promising high-TC piezoelectrics in the Bi-based perovskite family of BiMeO3-PbTiO3. In this study, zirconium is utilized to further improve the high temperature piezoelectric properties of Bi(Mg1/2Ti1/2)O3-PbTiO3. Substitution of Zr for Ti is observed to decrease the tetragonality (c/a) near the morphotropic phase boundary, while TC can be well maintained by the substitution of smaller and ferroelectrically active Ti by a larger and ferroelectrically weaker Zr cation. A softer coercive field and enhanced domain mobility is observed, ultimately leading to a strong ferroelectric activity. The piezoelectric property of Zr-substituted Bi(Mg1/2Ti1/2)O3-PbTiO3 is enhanced to 260 pC/N, when compared with Bi(Mg1/2Ti1/2)O3-PbTiO3 (225 pC/N). Good high temperature piezoelectric property was found in the tetragonal phase of Zr-substituted Bi(Mg1/2Ti1/2)O3-PbTiO3. Thermal depoling of aligned domains for this composition occurs at approximately 300 °C. Thus, Zr-substituted Bi(Mg1/2Ti1/2)O3-PbTiO3 could be used for high temperature actuator applications. Furthermore, an apparent ferroelectric-antiferroelectric phase transition was observed as a function of both the composition in the rhombohedral phase and the temperature. An antiferroelectric relaxor exists in the Zr-substituted Bi(Mg1/2Ti1/2)O3-PbTiO3.
A-site disorder driven sharp field-induced transition and collapse of charge ordering in Sm1/2Ca1/2-xSrxMnO3
Authors: Sabyasachi Sk. , Karmakar A. , Majumdar S. , Giri S. , Das S. , Amaral V. S.
Published: October 2012

Our study on Sm1/2Ca1/2−xSrxMnO3 (x = 0, 1/6, 1/3, and 1/2) system shows an unusual consequence in magnetic field-induced transition to ferromagnetic metallic state and collapse of charge ordering in the intermediate compositions. Interestingly, the transition is sharp or step-like at low temperature that is observed at much lower field (∼75 kOe) for intermediate compositions than the end compositions (not visible up to 100 kOe). The atomic-scale local inhomogeneity/distortion arising from ionic mismatch due to doping is supposed to be critical behind this field-induced transition. The charge ordering temperature observed from magnetization and magnetoresistance studies decreases with increasing x which is consistent with the results for R1/2A1/2MnO3 (R = La − Sm, A = Ca, Sr) family.
Improved performances of polymer-based dielectric by using inorganic/organic core-shell nanoparticles
Authors: Benhadjala W. , Bord-Majek I. , Béchou L. , Suhir E. , Buet M. , Rougé F. , Gaud V. , Plano B. , Ousten Y.
Published: October 2012

BaTiO3/hyperbranched polyester/methacrylate core-shell nanoparticles were studied by varying the shell thickness and the methacrylate ratio. We demonstrated that coalescence typically observed in traditional composites employing polymer matrices is significantly reduced. By modifying the shell thickness, the equivalent filler fraction was tuned from 7 wt. % to 41 wt. %. Obtained permittivities were compared with reported models for two-phase mixtures. The nonlinear behavior of the dielectric constant as a function of the equivalent filler fraction has been fitted with the Bruggeman equation. Methacrylate groups reduce by a decade the loss factor by improving nanoparticles adhesion. The permittivity reaching 85 at 1 kHz makes core-shell nanoparticles a promising material for embedded capacitors.
Direct measurement of laser-induced frequency shift rate of ultracold cesium molecules by analyzing losses of trapped atoms
Authors: Zhang Yichi , Ma Jie , Li Yuqing , Wu Jizhou , Zhang Linjie , Chen Gang , Wang Lirong , Zhao Yanting , Xiao Liantuan , Jia Suotang
Published: October 2012

We report on a quantitative experimental determination of the laser-induced frequency shift rate of the ultracold cesium molecules formed via photoassociation (PA) by means of the trap loss measurement of the losses of trapped atoms in a standard magneto-optical trap. The experiment was directly performed by varying the photoassociation laser intensity without any additional frequency monitor technologies. Our experimental method utilized dependences of the losses on the laser-induced frequency shift rate based on the conditions of the identified photoassociation spectral shape. We demonstrated that the method is sensitive enough to determine small frequency shifts of rovibrational levels of ultracold cesium molecules.
Can flexibility help you float?
Authors: Burton L. J. , Bush J. W. M.
Published: October 2012

We consider the role of flexibility in the weight-bearing characteristics of bodies floating at an interface. Specifically, we develop a theoretical model for a two-dimensional thin floating plate that yields the maximum stable plate load and optimal stiffness for weight support. Plates small relative to the capillary length are primarily supported by surface tension, and their weight-bearing potential does not benefit from flexibility. Above a critical size comparable to the capillary length, flexibility assists interfacial flotation. For plates on the order of and larger than the capillary length, deflection from an initially flat shape increases the force resulting from hydrostatic pressure, allowing the plate to support a greater load. In this large plate limit, the shape that bears the most weight is a semicircle, which displaces the most fluid above the plate for a fixed plate length. Exact results for maximum weight-bearing plate shapes are compared to analytic approximations made in the limits of large and small plate sizes. The value of flexibility for floating to a number of biological organisms is discussed in light of our study.
Flow geometry controls viscous fingering
Authors: Wilson R. Mark
Published: October 2012

A gradient in channel depth can suppress the instability that occurs when a less viscous fluid invades a more viscous one.
The seed ecology of two invasive Hieracium (Asteraceae) species
Authors: Bear Jennifer L. , Giljohann Katherine M. , Cousens Roger D. , Williams Nicholas S. G.
Published: October 2012

Two highly invasive hawkweeds, Hieracium aurantiacum and H. praealtum L., have established in the Australian Alps. Our experiments aimed to provide a better understanding of the seed ecology of these species, essential if successful eradication strategies are to be developed. Results indicated that viable seeds are produced in large numbers. Seeds germinate spontaneously and synchronously with light and moisture and are killed when exposed to temperatures above 110°C for 150 s. No seedlings of H. aurantiacum emerged from soil samples taken from a chronosequence of known infestations, but some H. praealtum seedlings emerged from soil sampled from sites where plants flowered the preceding summer. Germination was greatly reduced for both species under darkness, and few seedlings emerged when buried. Where herbicides were applied at a late stage of fruit development, hawkweeds continued to produce viable seeds, albeit in reduced numbers. Overall, our findings indicate that both species produce a large amount of seed, little of which enters the long-term soil seed bank. This, and the limited ability of buried seeds to germinate and/or emerge, means that Hieracium control programs should emphasise short-term (1–2-year) monitoring of treated sites and stress the importance of reducing the seed set.
Movement Patterns, Habitat Use, and Survival of Lahontan Cutthroat Trout in the Truckee River
Authors: Alexiades Alexander V. , Peacock Mary M. , Al-Chokhachy Robert
Published: October 2012

Habitat fragmentation, hybridization, and competition with nonnative salmonids are viewed as major threats to Lahontan cutthroat trout Oncorhynchus clarkii henshawi. Understanding Lahontan cutthroat trout behavior and survival is a necessary step in the reintroduction and establishment of naturally reproducing populations of Lahontan cutthroat trout. We used weekly radiotelemetry monitoring to examine movement patterns, habitat use, and apparent survival of 42 hatchery-reared Lahontan cutthroat trout in a 16.5-km stretch of the Truckee River, Nevada, across three reaches separated by barriers to upstream movement. We found differences in total movement distances and home range sizes of fish in different reaches within our study area. Fish used pool habitats more than fast water habitats in all reaches. Time of year, stream temperature, and fish standard length covariates had the strongest relationship with apparent survival. Monthly apparent survival was lowest in January, which coincided with the lowest flows and temperatures during the study period. Our results verify the mobility of Lahontan cutthroat trout and indicate that conditions during winter may limit the survival and reintroduction success in the portions of the Truckee River evaluated in this study.

Received December 1, 2011; accepted June 28, 2012
Reassessment of the Fecundity of California Sheephead
Authors: Loke-Smith Kerri A. , Floyd Alyssa J. , Lowe Christopher G. , Hamilton Scott L. , Caselle Jennifer E. , Young Kelly A.
Published: October 2012

Fecundity estimates used in a 2004 stock assessment to evaluate the overall health of the population of California sheephead Semicossyphus pulcher were based primarily on two studies. The first estimated the total fecundity of only nine individuals captured near Santa Catalina Island, California, and the second estimated batch fecundity of individuals taken from only one artificial reef. In order to develop a current and more comprehensive estimate of fecundity, we collected California sheephead from seven locations off southern California throughout the spawning season (July through September). To estimate both total fecundity and batch fecundity, we categorized and counted oocytes from ovarian subsamples of 28 and 24 (respectively) mature females (stage 3, spawning capable; determined by histological analysis). Total and batch fecundity increased with somatic mass, standard length, and ovary mass. We found total fecundity to increase with somatic mass to a power of 5.5, which is considerably greater than the value (2.95) reported previously. Our observations therefore highlight the importance of large females in the reproductive potential of the California sheephead stock. Regression analysis indicates that ovary mass is the most accurate biological indicator of fecundity for California sheephead and should be used for subsequent stock analyses.

Received January 27, 2012; accepted June 19, 2012
S-nitrosylation of B23/nucleophosmin by GAPDH protects cells from the SIAH1–GAPDH death cascade
Authors: Lee Sang Bae , Kim Chung Kwon , Lee Kyung-Hoon , Ahn Jee-Yin
Published: October 2012

B23/nucleophosmin is a multifunctional protein that participates in cell survival signaling by shuttling between the nucleolus/nucleoplasm and nucleus/cytoplasm. In this paper, we report a novel neuroprotective function of B23 through regulation of the SIAH1–glyceraldehyde-3-phosphate dehydrogenase (GAPDH) death cascade. B23 physiologically bound to both SIAH1 and GAPDH, disrupting the SIAH1–GAPDH complex in the nucleus in response to nitrosative stress. S-nitrosylation of B23 at cysteine 275 by trans-nitrosylation from GAPDH dramatically reduced the interaction between SIAH1 and GAPDH. S-nitrosylation of B23 enhanced B23–SIAH1 binding and mediated the neuroprotective actions of B23 by abrogating the E3 ligase activity of SIAH1. In mice, overexpression of B23 notably inhibited N-methyl-d-aspartate–mediated neurotoxicity, whereas expression of the C275S mutant, which is defective in binding to SIAH1, did not prevent neurotoxicity. Thus, B23 regulates neuronal survival by preventing SIAH1–GAPDH death signaling under stress-induced conditions in the brain.
Creating reusable tools from scripts: the Galaxy Tool Factory
Authors: Lazarus Ross , Kaspi Antony , Ziemann Mark ,   The Galaxy Team
Published: October 2012

Motivation: Galaxy is a software application supporting high-throughput biology analyses and work flows, available as a free on-line service or as source code for local deployment. New tools can be written to extend Galaxy, and these can be shared using public Galaxy Tool Shed (GTS) repositories, but converting even simple scripts into tools requires effort from a skilled developer.

Results: The Tool Factory is a novel Galaxy tool that automates the generation of all code needed to execute user-supplied scripts, and wraps them into new Galaxy tools for upload to a GTS, ready for review and installation through the Galaxy administrative interface.

Availability and implementation: The Galaxy administrative interface supports automated installation from the main GTS. Source code and support are available at the project website, https://bitbucket.org/fubar/galaxytoolfactory. The Tool Factory is implemented as an installable Galaxy tool.

Contact:  ross.lazarus@channing.harvard.edu
Temperature changes and energy inputs in giant planet atmospheres: what we are learning from H
3
+
Authors: Stallard Tom S. , Melin Henrik , Miller Steve , O'Donoghue James , Cowley Stan W. H. , Badman Sarah V. , Adriani Alberto , Brown Robert H. , Baines Kevin H.
Published: October 2012

Since its discovery at Jupiter in 1988, emission from H

has been used as a valuable diagnostic tool in our understanding of the upper atmospheres of the giant planets. One of the lasting questions we have about the giant planets is why the measured upper atmosphere temperatures are always consistently hotter than the temperatures expected from solar heating alone. Here, we describe how H

forms across each of the planetary disks of Jupiter, Saturn and Uranus, presenting the first observations of equatorial H

at Saturn and the first profile of H

emission at Uranus not significantly distorted by the effects of the Earth's atmosphere. We also review past observations of variations in temperature measured at Uranus and Jupiter over a wide variety of time scales. To this, we add new observations of temperature changes at Saturn, using observations by Cassini. We conclude that the causes of the significant level of thermal variability observed over all three planets is not only an important question in itself, but that explaining these variations could be the key to answering the more general question of why giant planet upper atmospheres are so hot.
Stabilization of H
+
–H
2
collision complexes between 11 and 28K
Authors: Plašil Radek , Zymak Illia , Jusko Pavol , Mulin Dmytro , Gerlich Dieter , Glosík Juraj
Published: October 2012

Formation of

via association of H
+
with H
2
has been studied at low temperatures using a 22-pole radiofrequency trap. Operating at hydrogen number densities from 10
11
to 10
14
 cm
−3
, the contributions of radiative,
k
r
, and ternary,
k
3
, association have been extracted from the measured apparent binary rate coefficients,
k
*=
k
r
+
k
3
[H
2
]. Surprisingly,
k
3
is constant between 11 and 22 K, (2.6±0.8)×10
−29
 cm
6
 s
−1
, while radiative association decreases from
k
r
(11 K)=(1.6±0.3)×10
−16
 cm
3
 s
−1
to
k
r
(28 K)=(5±2)×10
−17
 cm
3
 s
−1
. These results are in conflict with simple association models in which formation and stabilization of the complex are treated separately. Tentative explanations are based on the fact that, at low temperatures, only few partial waves contribute to the formation of the collision complex and that ternary association with H
2
may be quite inefficient because of the ‘shared proton’ structure of

.
Chemistry, astronomy and physics of H
3
+
Authors: Oka Takeshi
Published: October 2012

The great developments in the chemistry, astronomy and physics of H
3
+
since 2006, which have led to this Royal Society Theo Murphy Meeting, are reviewed.
Zygosaccharomyces sapae sp. nov., isolated from Italian traditional balsamic vinegar
Authors: Solieri Lisa , Chand Dakal Tikam , Giudici Paolo
Published: October 2012

Fourteen yeast isolates were recovered from two traditional balsamic vinegar (TBV) samples collected in the provinces of Modena and Reggio Emilia, Italy. Microsatellite-primed-PCR (MSP-PCR) was used to de-replicate the isolate collection into two representative strains, ABT301Tand ABT601. Phylogenetic analysis based on the D1/D2 domains of the 26S rRNA gene indicated that these strains represented a distinct species of the genusZygosaccharomyces, closely related toZygosaccharomyces rouxiiandZygosaccharomyces mellis. Physiological and morphological tests supported the recognition of a novel taxon of halotolerant, osmotolerant, non-psychrotolerant and maltose-fermentation-negative yeasts showing a chain or star-shaped pattern of budding cells, which remained attached to each other. Morphological observations offered evidence of ascospore formation. A novel species,Zygosaccharomyces sapaesp. nov., is proposed to accommodate these strains, with strain ABT301T( = CBS 12607T = MUCL 54092T) as the type strain. Based on D1/D2 domain phylogenetic analysis, the novel strains shared the highest sequence similarity (100 %) withZygosaccharomycessp. strain NCYC 3042, previously isolated from sugar [James, S. A., Bond, C. J., Stratford, M. & Roberts, I. N. (2005).FEMS Yeast Res5, 747–755]. However, based on phylogenetic (internal transcribed spacers, ITS), PCR fingerprinting and physiological analyses, marked differences were observed between the novel species and strain NCYC 3042, and these results are discussed in more detail.
Translating genomic information into clinical medicine: Lung cancer as a paradigm
Authors: Levy Mia A. , Lovly Christine M. , Pao William
Published: October 2012

We are currently in an era of rapidly expanding knowledge about the genetic landscape and architectural blueprints of various cancers. These discoveries have led to a new taxonomy of malignant diseases based upon clinically relevant molecular alterations in addition to histology or tissue of origin. The new molecularly based classification holds the promise of rational rather than empiric approaches for the treatment of cancer patients. However, the accelerated pace of discovery and the expanding number of targeted anti-cancer therapies present a significant challenge for healthcare practitioners to remain informed and up-to-date on how to apply cutting-edge discoveries into daily clinical practice. In this Perspective, we use lung cancer as a paradigm to discuss challenges related to translating genomic information into the clinic, and we present one approach we took at Vanderbilt-Ingram Cancer Center to address these challenges.
Mammary Fat Pad Tumor Preparation in Mice: Figure 1.
Authors: Jain Rakesh K. , Munn Lance L. , Fukumura Dai
Published: October 2012

The host microenvironment influences tumor biology, affecting parameters such as gene expression, angiogenesis, growth, invasion, metastasis, and responses to therapy. Consequently, the use of tumor models growing in appropriate orthotopic locations is necessary to obtain a rigorous understanding of tumor pathophysiology and to correctly study antitumor treatments. The mouse mammary fat pad serves as an orthotopic site for breast cancer and can be used to study various aspects of this disease, including the effect of host–tumor interactions on tumor biology and therapeutic response. This protocol describes mammary fat pad tumor preparation in mice.
Molecular events in matrix protein metabolism in the aging kidney
Authors: Sataranatarajan Kavithalakshmi , Feliers Denis , Mariappan Meenalakshmi M. , Lee Hak Joo , Lee Myung Ja , Day Robert T. , Yalamanchili Hima Bindu , Choudhury Goutam G. , Barnes Jeffrey L. , Van Remmen Holly , Richardson Arlan , Kasinath Balakuntalam S.
Published: October 2012

We explored molecular events associated with aging‐induced matrix changes in the kidney. C57BL6 mice were studied in youth, middle age, and old age. Albuminuria and serum cystatin C level (an index of glomerular filtration) increased with aging. Renal hypertrophy was evident in middle‐aged and old mice and was associated with glomerulomegaly and increase in mesangial fraction occupied by extracellular matrix. Content of collagen types I and III and fibronectin was increased with aging; increment in their mRNA varied with the phase of aging. The content of ZEB1 and ZEB2, collagen type I transcription inhibitors, and their binding to the collagen type Iα2 promoter by ChIP assay also showed age‐phase‐specific changes. Lack of increase in mRNA and data from polysome assay suggested decreased degradation as a potential mechanism for kidney collagen type I accumulation in the middle‐aged mice. These changes occurred with increment in TGFβ mRNA and protein and activation of its SMAD3 pathway; SMAD3 binding to the collagen type Iα2 promoter was also increased. TGFβ‐regulated microRNAs (miRs) exhibited selective regulation. The renal cortical content of miR‐21 and miR‐200c, but not miR‐192, miR‐200a, or miR‐200b, was increased with aging. Increased miR‐21 and miR‐200c contents were associated with reduced expression of their targets, Sprouty‐1 and ZEB2, respectively. These data show that aging is associated with complex molecular events in the kidney that are already evident in the middle age and progress to old age. Age‐phase‐specific regulation of matrix protein synthesis occurs and involves matrix protein–specific transcriptional and post‐transcriptional mechanisms.
The CRTH2 antagonist OC000459 reduces nasal and ocular symptoms in allergic subjects exposed to grass pollen, a randomised, placebo‐controlled, double‐blind trial
Authors: Horak F. , Zieglmayer P. , Zieglmayer R. , Lemell P. , Collins L. P. , Hunter M. G. , Steiner J. , Lewis T. , Payton M. A. , Perkins C. M. , Pettipher R.
Published: October 2012

Background

CRTH2 mediates activation of Th2 cells, eosinophils and basophils in response to prostaglandin D2. The CRTH2 antagonist OC000459 has previously been demonstrated to reduce airway inflammation and improve lung function in moderate persistent asthma. The objective of the present study was to determine the involvement of CRTH2 in promoting nasal and ocular symptoms in allergic subjects exposed to grass pollen.

Methods

A single centre, randomised, double‐blind, placebo‐controlled, two‐way crossover study was conducted in 35 male subjects allergic to grass pollen comparing OC000459 200 mg bid with placebo for 8 days. Subjects were exposed to grass pollen (≥1400 grains/m3) for 6 h on the 2nd and 8th days of treatment and assessed for nasal symptoms, ocular symptoms, other symptoms, nasal secretion weight and rhinomanometry over the 6‐h period. After a washout period of 3 weeks, subjects were switched to the alternative treatment for a further 8 days. The trial was registered on the clinical trials.gov database (Identifier NCT01448902).

Results

During the first treatment period, treatment with OC000459 significantly reduced both nasal and ocular symptoms in allergic subjects compared with placebo after challenge with grass pollen. A significant effect was observed on the 2nd day of dosing which was increased on the 8th day of dosing. The therapeutic effects of OC000459 persisted into the second treatment period despite a 3‐week washout phase. The safety profile of OC000459 was similar to that of placebo.

Conclusion

Treatment with OC000459 was well tolerated and led to a significant and persistent reduction in the symptoms of rhinoconjunctivitis.
Short‐interval intracortical inhibition in knee extensors during locomotor cycling
Authors: Sidhu, S. K. , Cresswell A. G. , Carroll T. J.
Published: October 2012

Aim

Short‐interval intracortical inhibition (SICI) can provide information on changes in cortical responsiveness during voluntary contractions. It is, however, unknown whether the magnitude of SICI changes throughout the cycle of rhythmic movements such as leg cycling.

Methods

The effects of four conditioning stimulus (CS) intensities, 70, 80, 90 and 95% of active motor threshold (AMT), on the magnitude of SICI were tested during three conditions: (1) activation phase of the electromyography (EMG) burst, (2) deactivation phase of the EMG burst and (3) static contractions. The three conditions were matched for EMG amplitude and test motor‐evoked potential (MEP) size with reference to the vastus lateralis muscle. Responses were also recorded from rectus femoris and vastus medialis.

Results

short‐interval cortical inhibition was weak during static knee contractions (15% reduction in control MEP) relative to previous reports during contractions in other muscle groups. SICI was abolished during the activation phase of the knee extensor EMG burst (P > 0.05), but present (approx. 90% of control MEP size) during the deactivation phase of EMG (P < 0.05). Furthermore, inhibition was elicited at a lower CS intensity during the deactivation phase of EMG during cycling than during static contractions (70 AMT vs. 90% AMT).

Conclusion

The results suggest that the efficacy of intracortical inhibitory projections to knee extensor corticomotoneurons is particularly weak during muscle activation. A lower threshold of activation for inhibitory cells during deactivation phase of cycling EMG was evident, and there was a phasic modulation of intracortical inhibition affecting corticospinal projections to the working muscles.
Clinical Outcomes After Tricuspid Valve Annuloplasty in Addition to Mitral Valve Surgery
Authors: Koppers Gille , Verhaert David , Verbrugge Frederik H. , Reyskens Rozette , Gutermann Herbert , Van Kerrebroeck Chris , Vandervoort Pieter , Tang W. H. Wilson , Dion Robert , Mullens Wilfried
Published: October 2012

©2012 Wiley Periodicals, inc.

Current guidelines recommend tricuspid valve annuloplasty (TVP) together with mitral valve surgery in cases of tricuspid annulus dilation (≥40 mm) or functional tricuspid valve regurgitation >2/4. Baseline clinical and echocardiographic data of patients undergoing mitral valve surgery in a single tertiary care hospital between 2007 and 2010 were analyzed. Mortality and heart failure hospitalization data were collected and groups with or without TVP were compared. Patients with TVP (n=89) had similar baseline characteristics compared with patients without (n=86), except for lower right ventricular fractional area change and more concomitant aortic valve surgery. Mortality was higher in the TVP group at 30 days (14% vs 5%; P=.04), but the difference was no longer significant at the end of follow‐up. More patients were hospitalized for heart failure in the TVP group (31% vs 17%; hazard ratio, 2.1; 95% confidence interval, 1.1–4.0; P=.05). Right ventricular sphericity index was the only preoperative parameter predicting death or heart failure hospitalizations. In conclusion, patients undergoing TVP in addition to mitral valve surgery are at high risk for early death or subsequent heart failure hospitalizations, which might be partly explained by more complex heart disease. The extent of preoperative right ventricular remodeling may be predictive of adverse outcomes.
Improved method of differentiation, selection and amplification of human melanocytes from the hair follicle cell pool
Authors: Savkovic Vuk , Dieckmann Christina , Milkova Linda , Simon Jan C.
Published: October 2012

Hair root harbours a complex cell pool with an immense developmental potential. Several lineages, including skin, can be differentiated from the multipotent to pluripotent cells of outer root sheath (ORS) of hair follicle. Outer root sheath presents the most opulent non‐invasively gained adult stem cell source known. For the purposes of cultivating melanocytes designated for graft‐based treatments of depigmentation disorders, we have established an ex vivo/in vitro cultivation method by introducing several methodological improvements to the ORS explant method of Dieckmann. As a result, we gained a higher, purer yield of differentiated melanocytes in half the time (at least 106 of 95% pure cells in 4 weeks). This reliable cultivation procedure begins with the epilation of 60 hairs and yields high numbers of ORS melanocytes that could be used for grafting applications. The procedure not only utilises the developmental potential of hair root cell pool and favors differentiation into melanocytes, but also contributes to the general trend of minimal‐to‐non‐invasive strategies for regenerative medicine.
Insight into the structure–function relationship of the nonheme iron halogenases involved in the biosynthesis of 4‐chlorothreonine – Thr3 from Streptomyces sp. OH‐5093 and SyrB2 from Pseudomonas syringae pv. syringae B301DR
Authors: Fullone Maria Rosaria , Paiardini Alessandro , Miele Rossella , Marsango Sara , Gross Dennis C. , Omura Satoshi , Ros‐Herrera Enric , Bonaccorsi di Patti Maria Carmela , Laganà Aldo , Pascarella Stefano , Grgurina Ingeborg
Published: October 2012

Molecular cloning of the biosynthetic gene cluster involved in the production of free 4‐chlorothreonine in Streptomyces sp. OH‐5093 showed the presence of six ORFs: thr1, thr2, thr3, orf1, orf2 and thr4. According to bioinformatic analysis, thr1, thr2, thr3 and thr4 encode a free‐standing adenylation domain, a carrier protein, an Fe(II) nonheme α‐ketoglutarate‐dependent halogenase and a thioesterase, respectively, indicating the role of these genes in the activation and halogenation of threonine and the release of 4‐chlorothreonine in a pathway closely reflecting the formation of this amino acid in the biosynthesis of the lipodepsipeptide syringomycin from Pseudomonas syringae pv. syringae B301DR. Orf1 and orf2 show sequence similarity with alanyl/threonyl‐tRNA synthetases editing domains and drug metabolite transporters, respectively. We show that thr3 can replace the halogenase gene syrB2 in the biosynthesis of syringomycin, by functional complementation of the mutant P. s. pv. syringae strain BR135A1 inactivated in syrB2. We also provide an insight into the structure–function relationship of halogenases Thr3 and SyrB2 using homology modelling and site‐directed mutagenesis.

Database

Nucleotide sequence data have been deposited in the ebi.ac.uk/EMBL/GenBank databases under accession numbers: thr1 (gi:378781338|CCF23454); thr2 (gi:378781340|CCF23456); thr3 (gi:378781341|CCF23457); orf1 (gi:378781342|CCF23458); orf2 (gi:378781343|CCF23459); thr4 (gi:378781344|CCF23460)