bluuebunny/crossref_metadata_2025 huggingface dataset:
Regulatory T Cells Accumulate and Proliferate in the Ischemic Hemisphere for up to 30 Days after MCAO
Authors: Stubbe Tobias , Ebner Friederike , Richter Daniel , Engel Odilo Randolf , Klehmet Juliane , Royl Georg , Meisel Andreas , Nitsch Robert , Meisel Christian , Brandt Christine
Published: September 2012

Local and peripheral immune responses are activated after ischemic stroke. In our present study, we investigated the temporal distribution, location, induction, and function of regulatory T cells (Tregs) and the possible involvement of microglia, macrophages, and dendritic cells after middle cerebral artery occlusion (MCAO). C57BL/6J and Foxp3EGFP transgenic mice were subjected to 30 minutes MCAO. On days 7, 14, and 30 after MCAO, Tregs and antigen presenting cells were analyzed using fluorescence activated cell sorting multicolor staining and immunohistochemistry. A strong accumulation of Tregs was observed on days 14 and 30 in the ischemic hemisphere accompanied by the elevated presence and activation of microglia. Dendritic cells and macrophages were found on each analyzed day. About 60% of Foxp3+ Tregs in ischemic hemispheres were positive for the proliferation marker Ki-67 on days 7 and 14 after MCAO. The transfer of naive CD4+ cells depleted of Foxp3+ Tregs into RAG1−/– mice 1 day before MCAO did not lead to a de novo generation of Tregs 14 days after surgery. After depletion of CD25+ Tregs, no changes regarding neurologic outcome were detected. The sustained presence of Tregs in the brain after MCAO indicates a long-lasting immunological alteration and involvement of brain cells in immunoregulatory mechanisms.
Stability of discrete breathers in nonlinear Klein-Gordon type lattices with pure anharmonic couplings
Authors: Yoshimura Kazuyuki
Published: September 2012

We consider the discrete breathers in one-dimensional nonlinear Klein-Gordon type lattices with pure anharmonic couplings. A discrete breather in the limit of vanishing couplings, i.e., the anti-continuous limit, consists of a number of in-phase or anti-phase excited particles, separated by particles at rest. Existence of the discrete breathers is proved for weak couplings by continuation from the anti-continuous limit. We prove a theorem which determines the linear stability of the discrete breathers. The theorem shows that the stability or instability of a discrete breather depends on the phase difference and distance between the two sites in each pair of adjacent excited sites in the anti-continuous solution. It is shown that there are two types of the dependence determined by the sign of αɛ, where α and ɛ are parameters such that positive (respectively, negative) α represents hard (respectively, soft) on-site nonlinearity and positive (respectively, negative) ɛ represents attractive (respectively, repulsive) couplings.
Quantum hydrodynamic model by moment closure of Wigner equation
Authors: Cai Zhenning , Fan Yuwei , Li Ruo , Lu Tiao , Wang Yanli
Published: September 2012

In this paper, we derive the quantum hydrodynamics models based on the moment closure of the Wigner equation. The moment expansion adopted is of the Grad type first proposed by Grad [“On the kinetic theory of rarefied gases,” Commun. Pure Appl. Math. 2(4), 331–407 (1949)10.1002/cpa.3160020403]. The Grad's moment method was originally developed for the Boltzmann equation. Recently, a regularization method for the Grad's moment system of the Boltzmann equation was proposed by Cai et al. [Commun. Pure Appl. Math. “Globally hyperbolic regularization of Grad's moment system” (in press)] to achieve the global hyperbolicity so that the local well-posedness of the moment system is attained. With the moment expansion of the Wigner function, the drift term in the Wigner equation has exactly the same moment representation as in the Boltzmann equation, thus the regularization applies. The moment expansion of the nonlocal Wigner potential term in the Wigner equation turns out to be a linear source term, which can only induce very mild growth of the solution. As a result, the local well-posedness of the regularized moment system for the Wigner equation remains as for the Boltzmann equation.
Zero-quantum stochastic dipolar recoupling in solid state nuclear magnetic resonance
Authors: Qiang Wei , Tycko Robert
Published: September 2012

We present the theoretical description and experimental demonstration of a zero-quantum stochastic dipolar recoupling (ZQ-SDR) technique for solid state nuclear magnetic resonance (NMR) studies of 13C-labeled molecules, including proteins, under magic-angle spinning (MAS). The ZQ-SDR technique combines zero-quantum recoupling pulse sequence blocks with randomly varying chemical shift precession periods to create randomly amplitude- and phase-modulated effective homonuclear magnetic dipole-dipole couplings. To a good approximation, couplings between different 13C spin pairs become uncorrelated under ZQ-SDR, leading to spin dynamics (averaged over many repetitions of the ZQ-SDR sequence) that are fully described by an orientation-dependent N × N polarization transfer rate matrix for an N-spin system, with rates that are inversely proportional to the sixth power of internuclear distances. Suppression of polarization transfers due to non-commutivity of pairwise couplings (i.e., dipolar truncation) does not occur under ZQ-SDR, as we show both analytically and numerically. Experimental demonstrations are reported for uniformly 13C-labeled L-valine powder (at 14.1 T and 28.00 kHz MAS), uniformly 13C-labeled protein GB1 in microcrystalline form (at 17.6 T and 40.00 kHz MAS), and partially labeled 13C-labeled protein GB1 (at 14.1 T and 40.00 kHz MAS). The experimental results verify that spin dynamics under ZQ-SDR are described accurately by rate matrices and suggest the utility of ZQ-SDR in structural studies of 13C-labeled solids.
Completeness-optimized basis sets: Application to ground-state electron momentum densities
Authors: Lehtola Jussi , Manninen Pekka , Hakala Mikko , Hämäläinen Keijo
Published: September 2012

In the current work we apply the completeness-optimization paradigm [P. Manninen and J. Vaara, J. Comput. Chem. 27, 434 (2006)10.1002/jcc.20358] to investigate the basis set convergence of the moments of the ground-state electron momentum density at the self-consistent field level of theory. We present a black-box completeness-optimization algorithm that can be used to generate computationally efficient basis sets for computing any property at any level of theory. We show that the complete basis set (CBS) limit of the moments of the electron momentum density can be reached more cost effectively using completeness-optimized basis sets than using conventional, energy-optimized Gaussian basis sets. By using the established CBS limits, we generate a series of smaller basis sets which can be used to systematically approach the CBS and to perform calculations on larger, experimentally interesting systems.
Flow past a normal flat plate undergoing inline oscillations
Authors: Khaledi Hatef A. , Andersson Helge I. , Barri Mustafa , Pettersen Bjørnar
Published: September 2012

The flow past an inline oscillating normal flat plate has been considered with the view to explore the variety of wake phenomena which arise even at the low Reynolds number (Re) equal to 100 based on the free stream velocity and the width of the plate. The three-dimensional Navier-Stokes equations were integrated in time over a wide range of excitation frequencies and amplitudes. A wake flow regime map was produced on the basis of the 24 computer simulations. For a certain excitation amplitude, the wake vortex shedding is first antisymmetric at low excitation frequencies fe. When fe is increased the wake first becomes chaotic and thereafter turns into a symmetric shedding mode, for instance the S-II mode with a binary vortex pair on each side of the wake. If fe is increased even further, more complex symmetric wake patterns may occur before the wake ultimately turns into chaos. Symmetric wakes are thus only observed in a band of intermediate excitation frequencies and then with the dominating flow frequency locked-on to fe. In one particular case, the S-II mode in the very near wake turned into what might be considered as a new S-IV mode which comprised four different vortex pairs per shedding cycle. In spite of the low Re considered, several cases exhibited distinct three-dimensionalities whereas some other cases remained strictly 2D. In some of the cases, at least, the transition from 2D to 3D wake flow was ascribed to a “mode competition.” Finally, for one of the two-dimensional cases the Reynolds number was first increased to 300 and then to 500 and a complex three-dimensional wake flow was observed. However, even at Re = 100, two-dimensional computer simulations are unable to reproduce the three-dimensional wake flow characteristics reported from the present study.
Rovibrationally selected ion-molecule collision study using the molecular beam vacuum ultraviolet laser pulsed field ionization-photoion method: Charge transfer reaction of N2+(X 2Σg+; v+ = 0–2; N+ = 0–9) + Ar
Authors: Chang Yih Chung , Xu Yuntao , Lu Zhou , Xu Hong , Ng C. Y.
Published: September 2012

We have developed an ion-molecule reaction apparatus for state-selected absolute total cross section measurements by implementing a high-resolution molecular beam vacuum ultraviolet (VUV) laser pulsed field ionization-photoion (PFI-PI) ion source to a double-quadrupole double-octopole ion-guide mass spectrometer. Using the total cross section measurement of the state-selected N2+(v+, N+) + Ar charge transfer (CT) reaction as an example, we describe in detail the design of the VUV laser PFI-PI ion source used, which has made possible the preparation of reactant N2+(X 2Σg+, v+ = 0–2, N+ = 0–9) PFI-PIs with high quantum state purity, high intensity, and high kinetic energy resolution. The PFI-PIs and prompt ions produced in the ion source are shown to have different kinetic energies, allowing the clean rejection of prompt ions from the PFI-PI beam by applying a retarding potential barrier upstream of the PFI-PI source. By optimizing the width and amplitude of the pulsed electric fields employed to the VUV-PFI-PI source, we show that the reactant N2+ PFI-PI beam can be formed with a laboratory kinetic energy resolution of ΔElab = ± 50 meV. As a result, the total cross section measurement can be conducted at center-of-mass kinetic energies (Ecm’s) down to thermal energies. Absolute total rovibrationally selected cross sections σ(v+ = 0–2, N+ = 0–9) for the N2+(X 2Σg+; v+ = 0–2, N+ = 0–9) + Ar CT reaction have been measured in the Ecm range of 0.04–10.0 eV, revealing strong vibrational enhancements and Ecm-dependencies of σ(v+ = 0–2, N+ = 0–9). The thermochemical threshold at Ecm = 0.179 eV for the formation of Ar+ from N2+(X; v+ = 0, N+) + Ar was observed by the measured σ(v+ = 0), confirming the narrow ΔEcm spread achieved in the present study. The σ(v+ = 0–2; N+) values obtained here are compared with previous experimental and theoretical results. The theoretical predictions calculated based on the Landau-Zener-Stückelberg formulism are found to be in fair agreement with the present measured σ(v+ = 1 or 2; N+). Taking into account of the experimental uncertainties, the measured σ(v+ = 1 or 2, N+) for N+ = 0–9 at Ecm = 0.04–10.0 eV are found to be independent of N+.
Structural and optical analyses of GaP/Si and (GaAsPN/GaPN)/GaP/Si nanolayers for integrated photonics on silicon
Authors: Nguyen Thanh T. , Robert C. , Guo W. , Létoublon A. , Cornet C. , Elias G. , Ponchet A. , Rohel T. , Bertru N. , Balocchi A. , Durand O. , Micha J. S. , Perrin M. , Loualiche S. , Marie X. , Le Corre A.
Published: September 2012

We report a structural study of molecular beam epitaxy-grown lattice-matched GaP/Si(0 0 1) thin layers with an emphasis on the interfacial structural properties, and optical studies of GaAsP(N)/GaP(N) quantum wells coherently grown onto the GaP/Si pseudo substrates, through a complementary set of characterization tools. Room temperature photoluminescence at 780 nm from the (GaAsPN/GaPN) quantum wells grown onto a silicon substrate is reported. Despite this good property, the time-resolved photoluminescence measurements demonstrate a clear influence of non-radiative defects initiated at the GaP/Si interface. It is shown from simulations, how x-ray diffraction can be used efficiently for analysis of antiphase domains. Then, qualitative and quantitative analyses of antiphase domains, micro-twins, and stacking faults are reported using complementarity of the local transmission electron microscopy and the statistical x-ray diffraction approaches.
Detuned resonances of Tollmien-Schlichting waves in an airfoil boundary layer: Experiment, theory, and direct numerical simulation
Authors: Würz W. , Sartorius D. , Kloker M. , Borodulin V. I. , Kachanov Y. S. , Smorodsky B. V.
Published: September 2012

Transition prediction in two-dimensional laminar boundary layers developing on airfoil sections at subsonic speeds and very low turbulence levels is still a challenge. The commonly used semi-empirical prediction tools are mainly based on linear stability theory and do not account for nonlinear effects present unavoidably starting with certain stages of transition. One reason is the lack of systematic investigations of the weakly nonlinear stages of transition, especially of the strongest interactions of the instability modes predominant in non-self-similar boundary layers. The present paper is devoted to the detailed experimental, numerical, and theoretical study of weakly nonlinear subharmonic resonances of Tollmien-Schlichting waves in an airfoil boundary layer, representing main candidates for the strongest mechanism of these initial nonlinear stages. The experimental approach is based on phase-locked hot-wire measurements under controlled disturbance conditions using a new disturbance source being capable to produce well-defined, complex wave compositions in a wide range of streamwise and spanwise wave numbers. The tests were performed in a low-turbulence wind tunnel at a chord Reynolds number of Re = 0.7 × 106. Direct numerical simulations (DNS) were utilized to provide a detailed comparison for the test cases. The results of weakly nonlinear theory (WNT) enabled a profound understanding of the underlying physical mechanisms observed in the experiments and DNS. The data obtained in experiment, DNS and WNT agree basically and provide a high degree of reliability of the results. Interactions occurring between components of various initial frequency-wavenumber spectra of instability waves are investigated by systematic variation of parameters. It is shown that frequency-detuned and spanwise-wavenumber-detuned subharmonic-type resonant interactions have an extremely large spectral width. Similar to results obtained for self-similar base flows it is found that the amplification factors in the frequency-detuned resonances can be even higher than in tuned cases, in spite of the strong base-flow non-self-similarity. An explanation of this unusual phenomenon is found based on the theoretical analysis and comparison of experimental, theoretical, and DNS data.
Effects of stress on the dielectric function of strained pseudomorphic Si1−xGex alloys from 0 to 75% Ge grown on Si (001)
Authors: Raja Muthinti Gangadhara , Medikonda Manasa , Adam Thomas , Reznicek Alexander , Diebold Alain C.
Published: September 2012

The dielectric function of bi-axially strained, intrinsic, and pseudomorphic Si1−xGex alloys was measured at room temperature using spectroscopic ellipsometry from 0.74 eV to 5.06 eV. Un-doped Si1−xGex with germanium compositions ranging from 0 to 75% was grown on Si (001) using chemical vapor deposition. High resolution x-ray diffraction was used to confirm sample composition, thickness, and strain. X-ray relaxation scans showed that all the samples were fully strained. All the alloy films in this study have low values of surface roughness, which allowed determination of the dielectric function. The presence of strain in the Si1−xGex alloys clearly altered the dielectric response. The bi-axial stress induced shift of the E1 and El + Δ1 critical point energies of pseudomorphic alloys can be described by the elastic response to the strain based on k*p theory [Lange et al., J. Appl. Phys. 80, 4578 (1996)]. Although the critical point energies of the alloys having higher germanium concentration showed deviations from the large shear approximation, the strain induced shift in critical point energy and the relative intensities of E1 and El + Δ1 were reasonably well described by the full elastic theory.
A light-driven turbine-like micro-rotor and study on its light-to-mechanical power conversion efficiency
Authors: Lin Xiao-Feng , Hu Guo-Qing , Chen Qi-Dai , Niu Li-Gang , Li Qi-Song , Ostendorf Andreas , Sun Hong-Bo
Published: September 2012

A light driven micro-rotor is a useful telecontrolled device free of mechanical contact for power supply. However, low efficiency in converting light to mechanical power detracts from its advantages because it incurs a high power consumption that might result in unwanted effects. For a systematic study on conversion efficiency, we designed a turbine-like micro-rotor and made a quantitative analysis by computational fluid dynamics and semiclassical optics. Much larger in size than those ever reported, our rotor could rotate at over 500 r/min. Denoted by average angular momentum transfer, its conversion efficiency was experimentally determined as high as 34.55 ℏ/photon.
Communication: Magnetic dipole transitions in the OH A 2Σ+ ← X 2Π system
Authors: Kirste Moritz , Wang Xingan , Meijer Gerard , Gubbels Koos B. , van der Avoird Ad , Groenenboom Gerrit C. , van de Meerakker Sebastiaan Y. T.
Published: September 2012

We report on the observation of magnetic dipole allowed transitions in the well-characterized A 2Σ+ − X 2Π band system of the OH radical. A Stark decelerator in combination with microwave Rabi spectroscopy is used to control the populations in selected hyperfine levels of both Λ-doublet components of the X 2Π3/2, v = 0, J = 3/2 ground state. Theoretical calculations presented in this Communication predict that the magnetic dipole transitions in the A 2Σ+, v = 1 ← X 2Π, v = 0 band are weaker than the electric dipole transitions by a factor of 2.58 × 103 only, i.e., much less than commonly believed. Our experimental data confirm this prediction.
Communication: Phase space wavelets for solving Coulomb problems
Authors: Shimshovitz Asaf , Tannor David J.
Published: September 2012

Recently we introduced a phase space approach for solving the time-independent Schrödinger equation using a periodic von Neumann basis with bi-orthogonal exchange (pvb) [A. Shimshovitz and D. J. Tannor, Phys. Rev. Lett. 109, 070402 (2012)10.1103/PhysRevLett.109.070402]. Here we extend the approach to allow a wavelet scaling of the phase space Gaussians. The new basis set, which we call the wavelet pvb basis, is simple to implement and provides an appealing alternative to other wavelet approaches. For the 1D Coulomb problems tested in this paper, the method reduces the size of the basis relative to the Fourier grid method by a factor of 13–60. The savings in basis set size is predicted to grow steeply as the dimensionality increases.
Molecular dynamic studies on anisotropic explosion of laser irradiated Xe cluster
Authors: Mishra Gaurav , Gupta N. K.
Published: September 2012

A three dimensional molecular dynamic model is used to investigate the dynamics of Xe clusters of various radii irradiated by laser of moderate intensities (∼1014−1016W/cm2). The FWHM pulse duration of the laser is varied from few laser cycles to hundreds of femtosecond. For cluster of radius 50 Å irradiated by a laser of 170 fs pulse duration, it is observed that ion yield is more along the direction of laser polarization than perpendicular to it. This trend reverses (more ions are emitted along the direction perpendicular to laser polarization than parallel to it) when laser pulses of few cycles are used. This reversal of anisotropy is explained on the basis of spatial shielding of ions due to the oscillating inner electron cloud along direction of laser electric field. The nature of anisotropy remains same with variations in laser intensity and cluster size.
Near-infrared photodetector consisting of J-aggregating cyanine dye and metal oxide thin films
Authors: Osedach Timothy P. , Iacchetti Antonio , Lunt Richard R. , Andrew Trisha L. , Brown Patrick R. , Akselrod Gleb M. , Bulović Vladimir
Published: September 2012

We demonstrate a near-infrared photodetector that consists of a thin film of the J-aggregating cyanine dye, U3, and transparent metal-oxide charge transport layers. The high absorption coefficient of the U3 film, combined with the use of a reflective anode and optical spacer layer, results in a zero-bias external quantum efficiency of 16.1 ± 0.1% (λ = 756 nm) for a device containing an 8.1 ± 0.3 nm-thick U3 film. The specific detectivity (D*) and response speed (f3dB) of a fully optimized device are measured to be (4.3 ± 0.1) × 1011 cm Hz1/2 W−1 and 92 kHz, respectively.
Effect of the polarity of carbon-fluorine bonds on the work function of plasma-fluorinated epitaxial graphene
Authors: Sherpa Sonam D. , Levitin Galit , Hess Dennis W.
Published: September 2012

Work function engineering of graphene facilitates its application as a transparent electrode material in organic electronic devices. Toward this end, we demonstrate the dependence of the work function of plasma-fluorinated epitaxial graphene on the polarity of carbon-fluorine bonds which is controlled by the nature of chemical bonding (ionic, semi-ionic, or covalent) between fluorine and carbon atoms. The work function of fluorinated graphene was measured using ultraviolet photoelectron spectroscopy and the polarity of carbon-fluorine bonds was established using x-ray photoelectron spectroscopy.
Synthesis, Antimicrobial Activity, and Molecular Docking Study of Some Novel Cyclophanes with Imino Intra-Annular Functionality
Authors: Rajakumar Perumal , Padmanabhan Ramar , Ramprasath Chandrasekaran , Mathivanan Narayanasamy , Silambarasan Vaidhyanathan , Velmurugan Devadasan
Published: September 2012

The synthesis and structural characterisation of novel imino cyclophanes incorporating various spacer units is described. All the imino cyclophanes exhibit comparable antibacterial activity against Gram positive (Bacillus subtillus, Staphylococcus aureus) and Gram negative (Escherchia coli, Klebsiella pneumonia) bacterial strains. The imino cyclophanes also exhibit good antifungal activity against human pathogenic fungus, Candida albicans.
Radiant flux density, energy density and fuel consumption in mixed-oak forest surface fires
Authors: Kremens R. L. , Dickinson M. B. , Bova A. S.
Published: September 2012

Closing the wildland fire heat budget involves characterising the heat source and energy dissipation across the range of variability in fuels and fire behaviour. Meeting this challenge will lay the foundation for predicting direct ecological effects of fires and fire–atmosphere coupling. In this paper, we focus on the relationships between the fire radiation field, as measured from the zenith, fuel consumption and the behaviour of spreading flame fronts. Experiments were conducted in 8 × 8-m outdoor plots using preconditioned wildland fuels characteristic of mixed-oak forests of the eastern United States. Using dual-band radiometers with a field of view of ~18.5 m2 at a height of 4.2 m, we found a near-linear increase in fire radiative energy density over a range of fuel consumption between 0.15 and 3.25 kg m–2. Using an integrated heat budget, we estimate that the fraction of total theoretical combustion energy density radiated from the plot averaged 0.17, the fraction of latent energy transported in the plume averaged 0.08, and the fraction accounted for by the combination of fire convective energy transport and soil heating averaged 0.72. Future work will require, at minimum, instantaneous and time-integrated estimates of energy transported by radiation, convection and soil heating across a range of fuels.
Implications of changing climate and atmospheric CO2 for grassland fire in south-east Australia: insights using the GRAZPLAN grassland simulation model
Authors: King Karen J. , Cary Geoffrey J. , Gill A. Malcolm , Moore Andrew D.
Published: September 2012

Climate and fuel characteristics influence fire regimes, and both need to be realistically considered in bushfire projections. Previous south-eastern Australian studies have assumed maximum grassland fuel curing (100%) and average fuel load (4.5 t ha–1). This study is the first to include daily fuel curing and load dynamics, derived from the agricultural pasture growth model GRAZPLAN, in projections of Grassland Fire Danger Index (GFDI) and potential fire-line intensity for future climate–CO2 combinations, and for alternate grasslands in the Canberra, Sydney and Melbourne regions. Climate-change projections were characterised by warmer, drier conditions, with atmospheric CO2 concentrations increasing for longer future timeframes. Projected shifts in GFDI and potential fire-line intensity arising from future climate–CO2 combinations were small compared with initial difference arising from using realistic GRAZPLAN-derived curing and fuel load values (compared with constant curing and fuel load) for grass dynamics, and this has important implications for the interpretation of earlier studies. Nevertheless, future grass curing and GFDI generally increased and fuel load generally decreased. The net effect on modelled future fire-line intensity was minimal because higher fire danger, and hence spread rate, was often largely compensated for by lower fuel load across the range of modelled grassland types and locations.
The bovine CD1D gene has an unusual gene structure and is expressed but cannot present α-galactosylceramide with a C26 fatty acid
Authors: Nguyen Thi Kim Anh , Koets Ad P. , Vordermeier Martin , Jervis Peter J. , Cox Liam R. , Graham Simon P. , Santema Wiebren J. , Moody D. Branch , van Calenbergh Serge , Zajonc Dirk M. , Besra Gurdyal S. , Van Rhijn Ildiko
Published: September 2012

Although CD1d and NKT cells have been proposed to have highly conserved functions in mammals, data on functions of CD1d and NKT cells in species other than humans and rodents are lacking. Upon stimulation with the CD1d-presented synthetic antigen α-galactosylceramide, human and rodent type I invariant NKT cells release large amounts of cytokines. The two bovine CD1D (boCD1D) genes have structural features that suggest that they cannot be translated into functional proteins expressed on the cell surface. Here we provide evidence that despite an intron–exon structure and signal peptide that are different from all other known CD1 genes, boCD1D can be translated into a protein that is expressed on the cell surface. However, in vivo treatment of cattle (Bos taurus) with 0.1, 1, or 10 µg kg–1 of the most commonly used α-galactosylceramide, which has a C26 fatty acid, did not lead to an increase in body temperature and serum cytokine levels of the animals. This lack of reactivity is not due to a complete inability of boCD1d to present glycosphingolipids because α-galactosylceramide variants with shorter fatty acids could be presented by boCD1d to human NKT cells in vitro. This suggests that the natural ligands of boCD1d are smaller lipids.
Survival, Germination, and Growth of Epichloë typhina and Significance of Leaf Wounds and Insects in Infection of Orchardgrass
Authors: Alderman Stephen C.
Published: September 2012

Epichloë typhina is an important stroma-producing endophytic ascomycete that is responsible for significant yield loss in orchardgrass (Dactylis glomerata) seed production fields. Infection is presumed to occur through leaves or stems, although details of the infection process and conditions that favor leaf infection are not well understood. The primary objectives of this study were to investigate the early stages of infection, including the effect of temperature or water potential on ascospore germination and subsequent growth of E. typhina, the tolerance of ascospores to desiccation, the requirement of leaf wounds for infection of orchardgrass by E. typhina, and the potential for insects to facilitate infection. Ascospores tolerated dry conditions, with at least 40% surviving 12 days under desiccation. Germination and growth of E. typhina was greatest at 25°C, with little to no growth at 5 and 35°C. Mycelial growth decreased with decreasing water potential from –0.3 to –10 MPa. Ascospore germination on leaves was predominantly hyphal at wound sites and iterative (conidiogenous) at sites without wounds. E. typhina typically entered leaves through wounds. Direct penetration was rarely observed and appeared to be associated with ascospore clusters. Germ tubes were significantly longer at sites with honeydew deposits from the bird cherry–oat aphid than at sites without honeydew. Growth of E. typhina was also observed at feeding sites of eriophyid mites, suggesting that leaf-wounding or sap-excreting insects support epiphyllous growth of E. typhina on leaves.
Identifying New Sources of Resistance to Eyespot of Wheat in Aegilops longissima
Authors: Sheng H. , Murray T. D.
Published: September 2012

Eyespot, caused by Oculimacula yallundae and O. acuformis, is an economically important disease of wheat. Currently, two eyespot resistance genes, Pch1 and Pch2, are used in wheat breeding programs but neither provides complete control or prevents yield loss. Aegilops longissima is a distant relative of wheat and proven donor of genes useful for wheat improvement, including disease resistance. Forty A. longissima accessions and 83 A. longissima chromosome addition or substitution lines were evaluated for resistance to eyespot. Among the 40 accessions tested, 43% were resistant to O. yallundae, 48% were resistant to O. acuformis, and 33% were resistant to both. Addition or substitution lines containing chromosomes 1S1, 2S1, 5S1, and 7S1, and a 4S17S1 translocation were resistant to O. yallundae. Chromosomes 1S1, 2S1, 4S1, and 5S1 contributed to resistance to O. acuformis more than others. Chromosomes 1S1, 2S1, 5S1, and 7S1 provided resistance to both pathogens. This is the first report of eyespot resistance in A. longissima. These results provide evidence that genetic control of eyespot resistance is present on multiple chromosomes of the S1 genome. This research demonstrates that A. longissima is a potential new source of eyespot resistance genes that could broaden the genetic diversity for wheat improvement.
Meta‐analysis: oral bisphosphonates and the risk of oesophageal cancer
Authors: Andrici J. , Tio M. , Eslick G. D.
Published: September 2012

Background

Bisphoshonates, which are used in the treatment and prevention of osteoporosis, have recently been implicated in the development of oesophageal cancer; however, studies report conflicting data.

Aim

To conduct a meta‐analysis of studies reporting on the association between bisphosphonates and oesophageal cancer to quantify the relationship.

Methods

A search was conducted through Medline, PubMed, Embase and Current Contents Connect to 2 August 2012. We calculated pooled odds ratios and 95% CIs using a random effects model for the risk of oesophageal cancer associated with exposure to bisphosphonates, as well as for the different periods of exposure.

Results

Seven studies, with 19 700 oesophageal cancer cases, met our inclusion criteria. We found a positive relationship between exposure to bisphosphonates and oesophageal cancer, with an odds ratio (OR) of 1.74 with a 95% CI of 1.19–2.55. Heterogeneity was observed (I2 = 85%, P < 0.001). Publication bias was not present. An increased risk of oesophageal cancer was also found in the group exposed to bisphosphonates for a longer period of time, compared with the group who experienced a shorter period of exposure (OR 2.32; 95% CI 1.57–3.43 vs. OR 1.35; 95% CI 0.77–2.39). An increased risk was associated with exposure to Etidronate (OR 1.58; 95% CI 1.12–2.24), but not to Aledronate.

Conclusions

Exposure to bisphosphonates may be associated with an increased risk of oesophageal cancer. More studies are needed to confirm the relationship.
Transient myeloproliferative disorder in children with Down syndrome: clarity to this enigmatic disorder
Authors: Gamis Alan S. , Smith Franklin O.
Published: September 2012

Children with trisomy 21 have a unique predisposition to develop a megakaryoblastic proliferative disease of varying severity during their first 3 months of life. This disorder exists in no other children or adults without the presence of trisomy 21 and only occurs in the fetal or neonatal period of life. Its spontaneous resolution in most cases further delineates it from otherwise indistinguishable neonatal leukaemias. The identification that GATA1 mutations are the leukaemogenic source along with three recently reported prospective clinical trials now provide a clearer understanding of this haematopoietic disorder. These recent advances in this enigmatic disorder, now known as Transient Myeloproliferative Disorder, are reviewed here in order to bring clarity to the breadth of organ involvement, the range of severity, the risk factors for mortality, the therapeutic options for severe manifestations, the natural course of spontaneous resolution regardless of therapy, and the elucidation of the subsequent risk for myeloid leukaemia.
Epidemiology of Subarachnoid Hemorrhage, Patterns of Management, and Outcomes in China: A Hospital‐Based Multicenter Prospective Study
Authors: Bian Li‐Heng , Liu Yan‐Fang , Nichols Li Tan , Wang Chun‐Xue , Wang Yi‐Long , Liu Gai‐Fen , Wang Wen‐Juan , Zhao Xing‐Quan
Published: September 2012

Aims

To conduct a large‐scale analysis on epidemiology, management, and outcomes of spontaneous subarachnoid hemorrhage (SAH), and to investigate the current situation of aneurysm obliteration in China.

Methods

A multicenter prospective cohort study involving 132 hospitals throughout China from September 2007 to August 2008 was conducted. A total of 651 patients with spontaneous SAH were evaluated.

Results

The most frequent type of SAH was aneurysmal SAH (77.4%), followed by uncommon causes (17.5%) and uncertain etiologies (5.1%). For aneurysmal SAH, the cumulative mortality at 28 days, 3 months, 6 months, and 12 months was 16.9%, 21.2%, 23.6%, and 24.6%, respectively. Obliteration of aneurysms, age, Hunt and Hess grade, and history of stroke affected the 12‐month mortality. In multiple regression analysis, the region, type of hospital, patient's age, history of hypertension, and nonintraventricular hemorrhage impacted aneurysm obliteration.

Conclusion

Aneurysmal rupture is the most common cause of spontaneous SAH in China. The percentage of aneurysm obliteration is still low in China that seems to contribute to long‐term mortality. With continued training of specialists, proper allocation of healthcare resources, and establishment of stroke centers, the rate of securing aneurysms is expected to rise.
How safe is it to manage diverticular colovesical fistulation non‐operatively?
Authors: Radwan R. , Saeed Z. M. , Phull J. S. , Williams G. L. , Carter A. C. , Stephenson B. M.
Published: September 2012

Aim  Colovesical fistula (CVF) is an uncommon condition. Diagnosis and management varies according to presentation and aetiology. The identification of patients suitable for conservative management and their outcome following this approach has not been well documented.

Methods  The clinical outcomes of all patients diagnosed with a CVF over a 7‐year period from an uro‐radiological database were reviewed. Cases secondary to diverticular disease were analysed with respect to the approach by which they were managed: those treated surgically and those managed conservatively.

Results  Sixty‐two patients (32 men) were diagnosed with CVF of whom 53 (85%) had diverticular disease. Twenty‐seven (mean age 69 years, range 42–90) underwent surgery (with a stoma in 59%) with a 30‐day mortality of 15%. Those managed conservatively (n = 26) were older (mean age 76 years, range 39–87) and frailer (62% American Society of Anesthesiologists Grades III and IV). At 1 and 3 years following diagnosis there was no difference in mortality between these two groups and only one death was as a consequence of urosepsis.

Conclusion  Many patients with CVF secondary to diverticular disease can be safely managed non‐operatively.
One‐hour post‐load plasma glucose and IGF‐1 in hypertensive patients
Authors: Perticone Francesco , Sciacqua Angela , Tassone Eliezer J. , Miceli Sofia , Maio Raffaele , Addesi Desirée , Falbo Tania , Arturi Franco , Sesti Giorgio
Published: September 2012

Eur J Clin Invest 2012; 42 (12): 1325–1331

Background  In normoglucose‐tolerant subjects (NGT), 1‐h post‐load plasma glucose value ≥155 mg/dL, during an oral glucose tolerance test (OGTT), is associated with an increased risk of type‐2 diabetes (T2D) and subclinical organ damage. Insulin‐like growth factor‐1 (IGF‐1) is involved in the pathogenesis of insulin resistance (IR) and T2D. Moreover, hypertensives have different degrees of IR and different levels of IGF‐1. Actually, there are no data supporting the association between post‐load glucose and IGF‐1; thus, the aim of the study was to investigate this relationship.

Materials and methods  We enrolled 1126 never‐treated hypertensive subjects who underwent an OGTT and clinical characterization. Insulin sensitivity was assessed by the Matsuda index. IGF‐1 was measured by a sensitive immunoradiometric assay.

Results  Among participants, 764 had NGT, 263 had impaired glucose tolerance (IGT) and 99 had T2D. According to the 1‐h post‐load plasma glucose cut‐off point of 155 mg/dL, we divided NGT subjects into NGT < 155 mg/dL and NGT ≥ 155 mg/dL. NGT ≥ 155 in comparison with NGT < 155 had significantly reduced insulin sensitivity and IGF‐1 levels. At multiple regression analysis, IGF‐1 was the major determinant of 1‐h post‐load glucose in NGT ≥ 155 subjects, IGT and diabetics, accounting for 20·9%, 17·7% and 15·5% of its variation in the respective models.

Conclusions  In hypertensive NGT ≥ 155 subjects, IGF‐1 results strongly associated with 1‐h post‐load glucose, similarly to that observed in IGT and diabetics. This finding has clinical relevance because both low IGF‐1 levels and 1‐h post‐load glucose in NGT subjects are associated with subclinical organ damage, an independent predictor of cardiovascular events.
Eye Images Increase Charitable Donations: Evidence From an Opportunistic Field Experiment in a Supermarket
Authors: Powell Kate L. , Roberts Gilbert , Nettle Daniel
Published: September 2012

A number of studies have shown that the presence of simple images of eyes in the environment increases prosocial behaviour in humans. However, questions remain about the robustness of the effect, its explanation and the factors promoting it. In particular, it is not yet clear whether this effect is restricted to contexts where there is a normative requirement to behave prosocially and thus where punishment is a likely consequence of failing to do so. In an 11‐wk field experiment in a supermarket, we displayed either eye images or control images on charity collection buckets. There was no normative requirement to donate in this setting, and most people did not do so. However, the presence of eye images increased donations by 48% relative to control images. The effect of eye images was significantly stronger at times when the supermarket was quiet rather than busy. Results are consistent with models of the evolution of prosociality through reputation‐based partner choice and have potential practical benefits for those involved in charitable fundraising.
Age, growth and hatch dates of ingressing larvae and surviving juveniles of Atlantic menhadenBrevoortia tyrannus
Authors: Lozano C. , Houde E. D. , Wingate R. L. , Secor D. H.
Published: September 2012

Ages, growth and hatch dates of ingressingBrevoortia tyrannuslarvae were determined in a 3 year sampling survey at the mouth of the Chesapeake Bay, U.S.A. To determine if otolith‐aged cohorts had variable relative survival, hatch dates of summer‐caught young‐of‐the‐year (YOY) juveniles collected throughout the Chesapeake Bay were compared with hatch dates of ingressing larvae. Modal total length of ingressing larvae was similar among years: 28 mm in 2005–2006 and 2007–2008, and 30 mm in 2006–2007. Ages of ingressing larvae ranged from 9 to 96 days post hatch (dph); mean ages were similar among years, but significantly older in 2006–2007 (50 dph) than in 2005–2006 (44 dph) and 2007–2008 (46 dph). Larval growth rates differed among years. Earliest growth, when larvae were offshore (0–20 dph), was faster in 2006–2007 (0·62 mm day−1), than in 2005–2006 and 2007–2008 (0·55 mm day−1in these years). Subsequently, from 30 to 80 dph, growth was slowest in 2006–2007. Hatch dates of ingressing larvae occurred from September to March and 90% (2007–2008) to 98% (2006–2007) had hatched prior to 31 December. In contrast, most surviving YOY juvenileB. tyrannushad hatched in January to February, suggesting selective mortality of early‐hatched individuals, apparently during the overwinter, larval to juvenile transition period.
Mind the gap: the minimal detectable separation distance between two objects during active electrolocation
Authors: Fechler K. , Holtkamp D. , Neusel G. , Sanguinetti‐Scheck J. I. , Budelli R. , von der Emde G.
Published: September 2012

In a food‐rewarded two‐alternative forced‐choice procedure, it was determined how well the weakly electric elephantnose fish Gnathonemus petersii can sense gaps between two objects, some of which were placed in front of complex backgrounds. The results show that at close distances, G. petersii is able to detect gaps between two small metal cubes (2 cm × 2 cm × 2 cm) down to a width of c. 1·5 mm. When larger objects (3 cm × 3 cm × 3 cm) were used, gaps with a width of 2–3 mm could still be detected. Discrimination performance was better (c. 1 mm gap size) when the objects were placed in front of a moving background consisting of plastic stripes or plant leaves, indicating that movement in the environment plays an important role for object identification. In addition, the smallest gap size that could be detected at increasing distances was determined. A linear relationship between object distance and gap size existed. Minimal detectable gap sizes increased from c. 1·5 mm at a distance of 1 cm, to 20 mm at a distance of 7 cm. Measurements and simulations of the electric stimuli occurring during gap detection revealed that the electric images of two close objects influence each other and superimpose. A large gap of 20 mm between two objects induced two clearly separated peaks in the electric image, while a 2 mm gap caused just a slight indentation in the image. Therefore, the fusion of electric images limits spatial resolution during active electrolocation. Relative movements either between the fish and the objects or between object and background might improve spatial resolution by accentuating the fine details of the electric images.
Antioxidative and antimicrobial activities of shrimp chitosan on gilthead sea bream (Sparus aurata) during refrigerated storage
Authors: Küçükgülmez Aygül , Kadak Ali Eslem , Gökçin Mehmet
Published: September 2012

This study aims to determine the effects of chitosan obtained from Metapenaeus stebbingi shells on the shelf life of refrigerated gilthead sea bream. It was determined that 1% chitosan‐coated samples had the lowest thiobarbituric acid (TBA) (3.05 mg malondialdehyde (MDA) kg−1) and free fatty acids (FFA) value (2.79% oleic acid), while the control group had the highest TBA (5.08 mg MDA kg−1) and FFA value (6.13% oleic acid) on the 27th day of storage. In the last day of storage, TVB‐N was found higher in control group (25.62 mg 100 g−1) than chitosan‐coated samples (14.57 mg 100 g−1). Total viable count value of the control group exceeded maximum permissible limit on the 27th day of storage. However, it was lower than 7.0 log CFU/g in chitosan‐coated samples during the refrigerated storage. As a result of this study, it was determined that shelf life of refrigerated gilthead sea bream can be increased up to 27 days with chitosan.
Shelf life extension of ground meat stored at 4 °C using chitosan and an oxygen absorber
Authors: Chounou Nikoleta , Chouliara Eirini , Mexis Stamatios F. , Stavros Kontakos , Georgantelis Dimitrios , Kontominas Michael G.
Published: September 2012

The combined effect of chitosan (1%) and an oxygen absorber on shelf life extension of fresh ground meat stored at 4 °C was investigated. Parameters monitored over a 10‐day storage period were Total Viable Count (TVC), Pseudomonas spp., Brochothrix thermosphacta, lactic acid bacteria, Enterobacteriaceae, pH, thiobarbituric acid (TBA), colour, odour and taste. Microbial populations were reduced by 0.4–2.0 log CFU g−1 for a given sampling day using either chitosan or the oxygen absorber, with the more pronounced effect being achieved by the combination of two. Thiobarbituric acid values for all samples increased during storage with the exception of samples treated with both chitosan and the oxygen absorber in which Thiobarbituric acid values decreased. Changes in pH values with time/different treatments were statistically insignificant. Colour parameters were affected by most treatments. On the basis of microbiological and sensory evaluation, a shelf life extension of 5–6 days was obtained for samples treated with the chitosan and the oxygen absorber combination.
Effect of a multi‐step preparation of amaranth and palm nut sauces on their carotenoid content and retinol activity equivalent values
Authors: Amoussa‐Hounkpatin Waliou , Mouquet‐Rivier Claire , Kayodé Adéchola Pierre Polycarpe , Hounhouigan Joseph Djidjoho , Avallone Sylvie
Published: September 2012

The preparation of a traditional sauce based on amaranth leaves cooked palm nuts or red palm oil (RPO) inBenin was described. The recipes included an optional step of leaf blanching at 100 °C, heating theRPOor boiling the palm nuts and finally cooking all the ingredients together. The influence of this multi‐step preparation on the carotenoid content of the final dish was measured. During blanching of amaranth leaves, violaxanthin was the only carotenoid to be significantly affected by the thermal treatment. Retinol activity equivalent (RAE) remained high after blanching even when alkaline traditional potash was added. Heating theRPOwas the most critical step because it considerably and very rapidly (in <3 min) decreased α‐carotene, β‐carotene andRAEvalues (more than 70%). Sauces calling for palm nuts,RPOand amaranth leaves were equally advantageous in terms of finalRAEvalue. These ingredients and sauces can thus be used in programmes to reduce vitaminAdeficiency.
Sample preparation and image acquisition using optical‐reflective microscopy in the measurement of fiber orientation in thermoplastic composites
Authors: VÉLEZ‐GARCÍA G.M. , WAPPEROM P. , KUNC V. , BAIRD D.G. , ZINK‐SHARP A.
Published: September 2012

A complete sample preparation procedure used to determine three‐dimensional fiber orientation from optical micrographs of glass fiber‐reinforced thermoplastic composites is presented. Considerations for elimination of irregularities in the elliptical footprints, contrast enhancement between fibers and surrounding polymer matrix, controlled‐etching that allows the identification of small shadows where fiber recedes into the matrix, and topographical reconstruction of the elliptical footprint are described in the procedure. This procedure has produced high‐quality optical micrographs employed to obtain accurate fiber orientation data for thermoplastic composites using the method of ellipses. The optimal definition of the nonelliptical footprints’ borders allows an accurate measurement of orientation in small sampling areas.