bluuebunny/crossref_metadata_2025 huggingface dataset:
Signature of exchange bias and spin-glass like phenomena in Fe/CoO nanocomposite
Authors: Pati S. P. , Roychowdhury A. , Kumar S. , Das D.
Published: March 2013

Nanocomposite of Fe/CoO having 10 at. wt. % of α-Fe has been prepared by the high energy ball-milling method. The average particle size was estimated to be 15 nm from the results obtained by the rietveld refinement of x-ray diffraction pattern. The presence of exchange coupling at the interface of ferromagnetic and antiferromagnetic components was confirmed from the shift observed in field-cooled (FC) magnetic hysteresis loop. Irreversibility in temperature dependent zero field cooled (ZFC)-FC magnetization at different applied fields indicates the presence of spin-glass like (SGL) phase. Memory effect observed in the temperature dependent dc-magnetization at FC condition confirmed the existence of SGL state. It is argued that polydispersity and defects at the interfaces of nanoparticles are the possible causes of the observed SGL phase.
Thermodynamic functions as correlation-function integrals
Authors: Koga K. , Widom B.
Published: March 2013

Expressions of some thermodynamic functions as correlation-function integrals, such as the Ornstein-Zernike integral, the Kirkwood-Buff integrals, and the integral formulas for virial coefficients, are recalled. It is noted, as has been remarked before, that the choice of molecular centers from which intermolecular distances are measured is arbitrary and that different choices lead to different forms of the correlation functions but that the integrals must be independent of those choices. This is illustrated with the second virial coefficients of hard spheres in one, two, and three dimensions, with that of gaseous propane in three dimensions, and with computer simulations of the pair correlations in water and in a dilute aqueous solution of propane.
First-principles investigations on the magnetic property in tripotassium doped picene
Authors: Zhong Guo-Hua , Zhang Chao , Wu Guang-Fen , Huang Zhong-Bing , Chen Xiao-Jia , Lin Hai-Qing
Published: March 2013

First-principles calculations are performed to investigate the magnetic characteristics in the tripotassium doped picene, especially for the effects induced by the volume variations. When changing volume, both crystal lattice constants and atomic positions are optimized. For the system with the experimental crystal volume, the doped picene shows a weak antiferromagnetic instability. When the volume expands from this experimental crystal volume, the antiferromagnetic spin ordering becomes clear. The electronic structures show that the magnetism comes from the spin unbalance on the π orbitals of the C atoms. On the contrary, both ferromagnetic and antiferromagnetic spin orderings are strongly suppressed as the volume is reduced. Our results indicate that the magnetism is sensitive to the variation of volume or pressure in the tripotassium doped picene. No metal-insulator transition is observed for several considered volumes.
Enhanced high harmonic generation and the phase effect in double-sided relativistic laser-foil interaction
Authors: Yu Yahong , Shen Baifei , Ji Liangliang , Zhang Xiaomei , Wang Wenpeng , Zhao Xueyan , Wang Xiaofeng , Yi Longqing , Shi Yin , Xu Tongjun , Zhang Lingang , Xu Zhizhan
Published: March 2013

High harmonic generation (HHG) from relativistic laser-foil interaction is investigated analytically and through particle-in-cell simulations. Previous work has shown that when two counter-propagating circularly polarized (CP) laser pulses interact with a thin foil, electrons can be well confined spatially to form a high density layer. The layer electrons oscillate in certain transversal direction and radiate intense high order harmonics. It is demonstrated here that there is a critical foil thickness, only below which can high harmonics be generated efficiently. Furthermore, to enhance the intensity in higher order region, the third linearly polarized (LP) short-wavelength laser pulse with much lower intensity is introduced. Analysis and simulations both show that the enhancement is determined by the relative phase δϕ between the driving CP laser pulses and LP pulse. The enhancement at high order is quite considerable and very sensitive to the relative phase δϕ, thus offering not only a way to efficiently produce HHG but also a new method to measure the phase of intense high-frequency laser pulses.
Full band calculations of the intrinsic lower limit of contact resistivity
Authors: Maassen J. , Jeong C. , Baraskar A. , Rodwell M. , Lundstrom M.
Published: March 2013

The intrinsic lower limit of contact resistivity (ρcLL) for InAs, In0.53Ga0.47As, GaSb, and Si is calculated using a full band ballistic quantum transport approach. Surprisingly, our results show that ρcLL is almost independent of the semiconductor. An analytical model, derived for 1D, 2D, and 3D, correctly reproduces the numerical results and explains why ρcLL is very similar in all cases. Our analysis sets a minimal carrier density required to meet the International Technology Roadmap for Semiconductors call for ρc=10−9 Ω-cm2 by 2023. Comparison with experiments shows there is room for improvement, which will come from optimizing interfacial properties.
Fermi level shift in La2−xSrxCuO4 probed by heteroepitaxial junctions with Nb-doped SrTiO3
Authors: Li B.-S. , Sawa A. , Okamoto H.
Published: March 2013

We investigated Fermi-level shifts with carrier doping in La2−xSrxCuO4 (LSCO) (x = 0–0.35) by using heteroepitaxial junctions with Nb–doped SrTiO3. The junctions showed highly rectifying current–voltage characteristics, in accord with the conventional theory of a Schottky or p-n diode. For x = 0–0.20, the built-in potential increased with increase of x, indicating the downward shift of the Fermi-level in La2−xSrxCuO4. The Fermi-level shift however reversed to upward at x ∼ 0.20. This behavior is related to the electronic-structure change, which is characterized by the reversal of dominant carrier type from hole to electron in overdoped La2−xSrxCuO4 confirmed by Hall measurements.
On reverse gate leakage current of GaN high electron mobility transistors on silicon substrate
Authors: Xia Ling , Hanson Allen , Boles Timothy , Jin Donghyun
Published: March 2013

Reverse leakage current characteristics of Ni Schottky contacts to GaN grown on Si is experimentally studied using high electron mobility transistors (HEMT). The temperature in this study is between 273 K and 428 K. The reverse gate leakage current is found to be dominated by Frenkel-Poole emission, a trap-assisted process, when the reverse electric field is smaller than 1.4 MV/cm. For electric field larger than 1.6 MV/cm, the underlying mechanism is mainly Fowler-Nordheim tunneling, an electric-field-dominated process. As a result, properly engineering electric field is considered critical for reducing reverse leakage current in GaN-on-Si HEMT for high-voltage applications.
Enhancement of asymmetric acoustic transmission
Authors: Sun Hong-xiang , Zhang Shu-yi
Published: March 2013

We report both experimentally and theoretically that enhanced one-way acoustic transmission is realized by coupling a periodical grating with metal plates. This exotic acoustic phenomenon is attributed to the structure-induced resonant excitation of the leaky Lamb modes which arise from the coupling of the diffracted waves with the resonant surface states localized at the interface of the grating and the metal plate. More importantly, we further optimize the structure by introducing two inclined plates, which can convert the reflected energy into the transmitted energy. Our finding has great potential applications in ultrasonic devices.
Dual roles of MoO3-doped pentacene thin films as hole-extraction and multicharge-separation functions in pentacene/C60 heterojunction organic solar cells
Authors: Lou Yan-Hui , Xu Mei-Feng , Wang Zhao-Kui , Naka Shigeki , Okada Hiroyuki , Liao Liang-Sheng
Published: March 2013

The authors demonstrate a pentacene/C60 heterojunction organic solar cell utilizing MoO3-doped pentacene thin films as an interfacial layer at anode and a multicharge-separation layer between pentacene and C60, respectively. The short-circuit current density and the open-circuit voltage were improved simultaneously compared with the reference device, resulting in an improvement in power conversion efficiency from 0.97% to 2.29%. Absorption spectra measurement, surface morphology analysis, and interfacial evaluation at anode side in the hole-dominant devices were carried out to reveal the functions of MoO3-doped pentacene films in OSCs.
Bandgap engineering of group IV materials for complementary n and p tunneling field effect transistors
Authors: Kotlyar R. , Avci U. E. , Cea S. , Rios R. , Linton T. D. , Kuhn K. J. , Young I. A.
Published: March 2013

Direct bandgap transition engineering using stress, alloying, and quantum confinement is proposed to achieve high performing complementary n and p tunneling field effect transistors (TFETs) based on group IV materials. The critical tensile stress for this transition decreases in Ge1−xSnx for Sn content 0≤x≤0.068, calculated with the Nonlocal Empirical Pseudopotential method. Direct sub eV bandgap leads to high ON current in both n and p Ge and Ge1−xSnx TFETs, simulated using the sp3d5s*-SO model. Ge and Ge1−xSnx show an advantage over III-V p TFETs achieving steep subthreshold operation, which is limited in III-V devices by their low density of electron states.
Electrical characteristics of hydrogen-terminated diamond metal-oxide-semiconductor with atomic layer deposited HfO2 as gate dielectric
Authors: Liu J. W. , Liao M. Y. , Imura M. , Oosato H. , Watanabe E. , Koide Y.
Published: March 2013

HfO2 films have been deposited on hydrogen-terminated diamond (H-diamond) by an atomic layer deposition (ALD) technique at 120 °C. Effect of rapid thermal annealing treatment on electrical properties of Au/Ti/Pd/ALD-HfO2/H-diamond metal-oxide-semiconductor (MOS) diodes has been investigated. The leakage current density of the MOS diode after annealing at 300 °C is as small as 10−8 A/cm2 at gate biases from −5.0 to 4.0 V. The capacitance-voltage curve in the depletion mode of the MOS diode after annealing is much sharper than that of the MOS diode before annealing and close to the theoretical dependence, which indicates the small interface state density. The annealed MOS diode is concluded to be more suitable for the fabrication of field effect transistors.
Improvement of Ge-on-Si photodiodes by black silicon light trapping
Authors: Steglich Martin , Zilk Matthias , Schrempel Frank , Tünnermann Andreas , Kley Ernst-Bernhard
Published: March 2013

A light-trapping scheme for normal incidence Ge-on-Si photodiodes, utilizing needle-like black silicon nanostructures is presented. Simulations reveal that light absorption in thin rear Ge films can be enhanced several times due to both the antireflection and the scattering effect of the nanostructure. It is shown that especially films with thicknesses ≤100 nm benefit from the black silicon nanostructure, e.g., resulting in a 5 to 10 times higher absorptance at 1500 nm for a 100 nm thick film. Theoretical predictions are experimentally proved by reflectance-transmittance measurements of crystalline Ge films sputtered on black silicon substrates.
Low temperature plasma-enhanced atomic layer deposition of thin vanadium nitride layers for copper diffusion barriers
Authors: Rampelberg Geert , Devloo-Casier Kilian , Deduytsche Davy , Schaekers Marc , Blasco Nicolas , Detavernier Christophe
Published: March 2013

Thin vanadium nitride (VN) layers were grown by atomic layer deposition using tetrakis(ethylmethylamino)vanadium and NH3 plasma at deposition temperatures between 70 °C and 150 °C on silicon substrates and polymer foil. X-ray photoelectron spectroscopy revealed a composition close to stoichiometric VN, while x-ray diffraction showed the δ-VN crystal structure. The resistivity was as low as 200 μΩ cm for the as deposited films and further reduced to 143 μΩ cm and 93 μΩ cm by annealing in N2 and H2/He/N2, respectively. A 5 nm VN layer proved to be effective as a diffusion barrier for copper up to a temperature of 720 °C.
Nonlinear resonant magnetoelectric interactions and efficient frequency doubling in a ferromagnetic-ferroelectric layered structure
Authors: Fetisov L. Y. , Fetisov Y. K. , Sreenivasulu G. , Srinivasan G.
Published: March 2013

Mechanical strain mediated non-linear magnetoelectric (NLME) coupling is studied in layered composites of ferromagnetic FeBSiC and piezoelectric lead zirconate titanate (PZT) bimorph. The NLME manifests as frequency doubling in the voltage response of the sample to an applied ac magnetic field. It is shown that NLME is strong (i) in the absence of DC magnetic bias, (ii) when the frequency of h is tuned to half the frequency for bending oscillations, and (iii) a PZT bimorph (instead of a single layer of PZT) is used. A model is discussed for the non-linear magnetoelectric coupling that is of interest for RF frequency doublers.
Salinity affects the response of soil microbial activity and biomass to addition of carbon and nitrogen
Authors: Mavi Manpreet S. , Marschner Petra
Published: March 2013

Addition of carbon (C) and nitrogen (N) to soil can enhance microbial tolerance to salinity, but it is not known if salinity changes the response of microbial activity and biomass to addition of C and N, or how nutrient addition affects microbial tolerance to salinity. We prepared salinity treatments of non-saline soil [electrical conductivity (EC1 : 5) 0.1 dS m–1] without salt addition or adjusted to four salinity levels (2.5, 5.0, 7.5, 10 dS m–1) using a combination of CaCl2 and NaCl. The soils were amended with 2.5 mg C g–1 as glucose or as mature wheat straw (C/N ratio 47 : 1), with NH4Cl added to glucose to achieve a C/N ratio similar to that of wheat straw, or with NH4Cl added to glucose or wheat straw to achieve a C/N ratio of 20. Soil respiration was measured over 30 days. Microbial biomass C and N (MBC, MBN), dissolved organic C (DOC), and total dissolved N (TDN) were measured on day 30. Cumulative respiration and MBC concentration decreased with increasing EC, less so with glucose than with wheat straw. The MBC concentration was more sensitive to EC than was cumulative respiration, irrespective of C source. Addition of N to glucose and wheat straw to bring the C/N ratio to 20 significantly decreased cumulative respiration and MBC concentration at a given EC. This study showed that in the short term, addition of a readily available and easily decomposable source of energy improves the ability of microbes to tolerate salinity. The results also suggest that in saline soils, irrespective of the C substrate, N addition has no impact, or a negative impact, on microbial activity and growth.
Rill and interrill erodibility and sediment characteristics of clayey Australian Vertosols and a Ferrosol
Authors: Reichert José Miguel , Norton L. Darrell
Published: March 2013

For soils and conditions outside the USA, input parameters for physically based soil erosion models, such as the WEPP model, are usually not available, particularly for tropical soils. In a laboratory study, small erosion pans and a programmable rain simulator were used to determine interrill erodibility, whereas in the field, rills were physically allocated in the field as plots of 0.1 by 10 m within a ridge–furrow arrangement and five water-inflow rates were applied sequentially to determine rill erodibility and critical hydraulic shear. During the rain or inflows, runoff samples were taken and flow was characterised. The soils tested were Grey Vertosol, Black Vertosol, and Red Ferrosol. The fall velocity parameter, V50, for rill soil and eroded sediment followed the order Red Ferrosol > Grey Vertosol > Black Vertosol, which Black Vertosol was the same order as observed for V50 and mean weight diameter (MWD) of aggregates in the interrill erosion experiment and D50 of interrill eroded sediment, demonstrating differences between soils in dispersion and aggregate stability. The estimated values obtained by the WEPP model were not comparable to laboratory interrill erodibility values or to field rill erodibility values. Thus, erodibility parameters for physically based erosion models such a WEPP should be determined in the field for tropical soils, and new equations need to be developed to estimate such values based on soil properties for tropical soils.
The Effects of Juvenile American Shad Planktivory on Zooplankton Production in Columbia River Food Webs
Authors: Haskell Craig A. , Tiffan Kenneth F. , Rondorf Dennis W.
Published: March 2013

Columbia River reservoirs support a large population of nonnative American Shad Alosa sapidissima that consume the zooplankton that native fishes also rely on. We hypothesized that the unprecedented biomass of juvenile American Shad in John Day Reservoir is capable of altering the zooplankton community if these fish consume a large portion of the zooplankton production. We derived taxon‐specific estimates of zooplankton production using field data and a production model from the literature. Empirical daily ration was estimated for American Shad and expanded to population‐level consumption using abundance and biomass data from hydroacoustic surveys. Daphnia spp. production was high in early summer but declined to near zero by September as shad abundance increased. American Shad sequentially consumed Daphnia spp., copepods, and Bosmina spp., which tracked the production trends of these taxa. American Shad evacuation rates ranged from 0.09 to 0.24/h, and daily rations ranged from 0.008 to 0.045 g·g−1·d−1 (dry weight) over all years. We observed peak American Shad biomass (45.2 kg/ha) in 1994, and daily consumption (1.6 kg/ha) approached 30% (5.3 kg/ha) of zooplankton production. On average, American Shad consumed 23.6% of the available zooplankton production (range, <1–83%). The changes in the zooplankton community are consistent with a top‐down effect of planktivory by American Shad associated with their unprecedented biomass and consumption, but the effects are likely constrained by temperature, nutrient flux, and the seasonal production patterns of zooplankton in John Day Reservoir. American Shad add to the planktivory exerted by other species like Neomysis mercedis to reduce the capacity of the reservoir to support other planktivorous fishes. The introduction of American Shad and other nonnative species will continue to alter the food web in John Day Reservoir, potentially affecting native fishes, including Pacific salmon Oncorhynchus spp.
Reproductive Biology of Pacific Ocean Perch and Northern Rockfish in the Aleutian Islands
Authors: TenBrink Todd T. , Spencer Paul D.
Published: March 2013

Estimates of maturity (i.e., the proportion of mature individuals at age) play an important role in assessing stock productivity; however, this information has not been published for rockfishes in the Aleutian Islands. Ovary and otolith samples were collected from Pacific Ocean Perch Sebastes alutus and Northern Rockfish S. polyspinis during both fishery-independent and fishery-dependent cruises in 2010 to investigate maturity and other aspects of reproductive biology. Histological examination of ovaries indicated that both species exhibited general parturition in April, while specimens caught in the summer and fall were maturing and generally exhibited progressive stages of vitellogenesis. Histological analysis was more reliable when characterizing ovary condition than were macroscopic or visual assessments during the developing period. Estimates of natural mortality, based on a relationship with the gonadosomatic index, were 0.040 for Pacific Ocean Perch and 0.042 for Northern Rockfish. Mean fecundity estimates calculated for Northern Rockfish (89,320 oocytes) were correlated more with length and weight than age. Estimates of age and length at 50% maturity were 9.1 years at 32.4 cm for Pacific Ocean Perch and 7.6 years at 27.7 cm for Northern Rockfish and indicate maturation at younger ages than do previous studies from the Gulf of Alaska. This information on reproductive biology will improve estimation of fishing mortality reference points and management of these commercially important species in the Aleutian Islands.

Received June 22, 2012; accepted December 10, 2012
An intercellular polyamine transfer via gap junctions regulates proliferation and response to stress in epithelial cells
Authors: Desforges Bénédicte , Curmi Patrick A. , Bounedjah Ouissame , Nakib Samir , Hamon Loic , De Bandt Jean-Pascal , Pastré David
Published: March 2013

In the organism, quiescent epithelial cells have the potential to resume cycling as a result of various stimuli, including wound healing or oxidative stress. Because quiescent cells have a low polyamine level, resuming their growth requires an increase of their intracellular polyamine levels via de novo polyamine synthesis or their uptake from plasma. Another alternative, explored here, is an intercellular exchange with polyamine-rich cycling cells via gap junctions. We show that polyamines promote gap junction communication between proliferating cells by promoting dynamical microtubule plus ends at the cell periphery and thus allow polyamine exchange between cells. In this way, cycling cells favor regrowth in adjacent cells deprived of polyamines. In addition, intercellular interactions mediated by polyamines can coordinate the translational response to oxidative stress through the formation of stress granules. Some putative in vivo consequences of polyamine-mediated intercellular interactions are also discussed regarding cancer invasiveness and tissue regeneration.
Self-organization of stabilized microtubules by both spindle and midzone mechanisms inXenopusegg cytosol
Authors: Mitchison Timothy J. , Nguyen Phuong , Coughlin Margaret , Groen Aaron C.
Published: March 2013

Previous study of self-organization of Taxol-stabilized microtubules into asters in Xenopus meiotic extracts revealed motor-dependent organizational mechanisms in the spindle. We revisit this approach using clarified cytosol with glycogen added back to supply energy and reducing equivalents. We added probes for NUMA and Aurora B to reveal microtubule polarity. Taxol and dimethyl sulfoxide promote rapid polymerization of microtubules that slowly self-organize into assemblies with a characteristic morphology consisting of paired lines or open circles of parallel bundles. Minus ends align in NUMA-containing foci on the outside, and plus ends in Aurora B–containing foci on the inside. Assemblies have a well-defined width that depends on initial assembly conditions, but microtubules within them have a broad length distribution. Electron microscopy shows that plus-end foci are coated with electron-dense material and resemble similar foci in monopolar midzones in cells. Functional tests show that two key spindle assembly factors, dynein and kinesin-5, act during assembly as they do in spindles, whereas two key midzone assembly factors, Aurora B and Kif4, act as they do in midzones. These data reveal the richness of self-organizing mechanisms that operate on microtubules after they polymerize in meiotic cytoplasm and provide a biochemically tractable system for investigating plus-end organization in midzones.
Egg mortality of northeast Arctic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus)†
Authors: Langangen Øystein , Stige Leif C. , Yaragina Natalia A. , Vikebø Frode B. , Bogstad Bjarte , Gusdal Yvonne
Published: March 2013

High and variable mortality during the egg and larval stages is thought to be an important source of interannual variability in stock size in many marine fish. However, quantitative information about the mortality during these life stages, especially interannual variability, is sparse. Here, we used a time-series covering 35 years (1959–1993) of survey data to estimate mortality during the egg stages of northeast Arctic cod (Gadus morhua) and Northeast Arctic haddock (Melanogrammus aeglefinus). Using a regression approach based on the numbers of eggs in different developmental stages, we calculated the mean instantaneous mortality rate of cod eggs to be 0.17 d−1 (95% CI: 0.15–0.19), which is significantly higher than that for haddock, 0.09 d−1 (95% CI: 0.07–0.12). Interannual variability in egg mortality ranges from ∼0.12 to ∼0.22 d−1 for cod and from ∼0.04 to ∼0.12 d−1 for haddock. The accuracy of these estimates was evaluated by the analysis of synthetic data constructed from a coupled physical–biological model, suggesting that mean mortality and the magnitude of interannual variability were estimated reliably, but not mortality for any given year.
Lipidome analysis of rotavirus-infected cells confirms the close interaction of lipid droplets with viroplasms
Authors: Gaunt Eleanor R. , Zhang Qifeng , Cheung Winsome , Wakelam Michael J. O. , Lever Andrew M. L. , Desselberger Ulrich
Published: March 2013

Rotaviruses (RVs) cause acute gastroenteritis in infants and young children, and are globally distributed. Within the infected host cell, RVs establish replication complexes in viroplasms (‘viral factories’) to which lipid droplet organelles are recruited. To further understand this recently discovered phenomenon, the lipidomes of RV-infected and uninfected MA104 cells were investigated. Cell lysates were subjected to equilibrium ultracentrifugation through iodixanol gradients. Fourteen different classes of lipids were differentiated by mass spectrometry. The concentrations of virtually all lipids were elevated in RV-infected cells. Fractions of low density (1.11–1.15 g ml−1), in which peaks of the RV dsRNA genome and lipid droplet- and viroplasm-associated proteins were observed, contained increased amounts of lipids typically found concentrated in the cellular organelle lipid droplets, confirming the close interaction of lipid droplets with viroplasms. A decrease in the ratio of the amounts of surface to internal components of lipid droplets upon RV infection suggested that the lipid droplet–viroplasm complexes became enlarged.
Rift Valley fever virus MP-12 vaccine encoding Toscana virus NSs retains neuroinvasiveness in mice
Authors: Indran Sabarish V. , Lihoradova Olga A. , Phoenix Inaia , Lokugamage Nandadeva , Kalveram Birte , Head Jennifer A. , Tigabu Bersabeh , Smith Jennifer K. , Zhang Lihong , Juelich Terry L. , Gong Bin , Freiberg Alexander N. , Ikegami Tetsuro
Published: March 2013

Rift Valley fever is a mosquito-borne zoonotic disease endemic to sub-Saharan Africa. Rift Valley fever virus (RVFV; genusPhlebovirus, familyBunyaviridae) causes high rates of abortion and fetal malformation in pregnant ruminants, and haemorrhagic fever, neurological disorders or blindness in humans. The MP-12 strain is a highly efficacious and safe live-attenuated vaccine candidate for both humans and ruminants. However, MP-12 lacks a marker to differentiate infected from vaccinated animals. In this study, we originally aimed to characterize the efficacy of a recombinant RVFV MP-12 strain encoding Toscana virus (TOSV) NSs gene in place of MP-12 NSs (rMP12-TOSNSs). TOSV NSs promotes the degradation of dsRNA-dependent protein kinase (PKR) and inhibits interferon-β gene up-regulation without suppressing host general transcription. Unexpectedly, rMP12-TOSNSs increased death in vaccinated outbred mice and inbred BALB/c or C57BL/6 mice. Immunohistochemistry showed diffusely positive viral antigens in the thalamus, hypothalamus and brainstem, including the medulla. No viral antigens were detected in spleen or liver, which is similar to the antigen distribution of moribund mice infected with MP-12. These results suggest that rMP12-TOSNSs retains neuroinvasiveness in mice. Our findings demonstrate that rMP12-TOSNSs causes neuroinvasion without any hepatic disease and will be useful for studying the neuroinvasion mechanism of RVFV and TOSV.
Identification and classification of feline endogenous retroviruses in the cat genome using degenerate PCR and in silico data analysis
Authors: Song Ning , Jo Haiin , Choi Minkyeung , Kim Jin-Hoi , Seo Han Geuk , Cha Se-Yeoun , Seo Kunho , Park Chankyu
Published: March 2013

The purpose of this study was to identify and classify endogenous retroviruses (ERVs) in the cat genome. Pooled DNA from five domestic cats was subjected to degenerate PCR with primers specific to the conserved retroviralpro/polregion. The 59 amplified retroviral sequences were used forin silicoanalysis of the cat genome (Felis_catus-6.2). We identified 219 ERV γ and β elements from cat genome contigs, which were classified into 42 ERV γ and 4 β families and further analysed. Among them, 99 γ and 5 β ERV elements contained the complete retroviral structure. Furthermore, we identified 757 spuma-like ERV elements based on the sequence homology to murine (Mu)ERV-L and human (H)ERV-L. To the best of our knowledge, this is the first detailed genome-scale analysis examiningFelis catusendogenous retroviruses (FcERV) and providing advanced insights into their structural characteristics, localization in the genome, and diversity.
An essential RNA element resides in a central region of hepatitis E virus ORF2
Authors: Emerson Suzanne U. , Nguyen Hanh T. , Torian Udana , Mather Karly , Firth Andrew E.
Published: March 2013

Hepatitis E virus (genus Hepevirus, family Hepeviridae) is one of the most important causes of acute hepatitis in adults, particularly among pregnant women, throughout Asia and Africa where mortality rates can be 20–30 %. Hepatitis E virus has a single-stranded positive-sense RNA genome that contains three translated ORFs. The two 3′ ORFs are translated from a subgenomic RNA. Functional RNA elements have been identified in and adjacent to the genomic 5′ and 3′ UTRs and in and around the intergenic region. Here we describe an additional RNA element that is located in a central region of ORF2. The RNA element is predicted to fold into two highly conserved stem–loop structures, ISL1 and ISL2. Mutations that disrupt the predicted structures, without altering the encoded amino acid sequence, result in a drastic reduction in capsid protein synthesis. This indicates that the RNA element plays an important role in one of the early steps of virus replication. The structures were further investigated using a replicon that expresses Gaussia luciferase in place of the capsid protein. Single mutations in ISL2 severely reduced luciferase expression, but a pair of compensatory mutations that were predicted to restore the ISL2 structure, restored luciferase expression to near-WT levels, thus lending experimental support to the predicted structure. Nonetheless the precise role of the ISL1+ISL2 element remains unknown.
Impact of the Carbon and Nitrogen Supply on Relationships and Connectivity between Metabolism and Biomass in a Broad Panel of Arabidopsis Accessions
Authors: Sulpice Ronan , Nikoloski Zoran , Tschoep Hendrik , Antonio Carla , Kleessen Sabrina , Larhlimi Abdelhalim , Selbig Joachim , Ishihara Hirofumi , Gibon Yves , Fernie Alisdair R. , Stitt Mark
Published: March 2013

Natural genetic diversity provides a powerful tool to study the complex interrelationship between metabolism and growth. Profiling of metabolic traits combined with network-based and statistical analyses allow the comparison of conditions and identification of sets of traits that predict biomass. However, it often remains unclear why a particular set of metabolites is linked with biomass and to what extent the predictive model is applicable beyond a particular growth condition. A panel of 97 genetically diverse Arabidopsis (Arabidopsis thaliana) accessions was grown in near-optimal carbon and nitrogen supply, restricted carbon supply, and restricted nitrogen supply and analyzed for biomass and 54 metabolic traits. Correlation-based metabolic networks were generated from the genotype-dependent variation in each condition to reveal sets of metabolites that show coordinated changes across accessions. The networks were largely specific for a single growth condition. Partial least squares regression from metabolic traits allowed prediction of biomass within and, slightly more weakly, across conditions (cross-validated Pearson correlations in the range of 0.27–0.58 and 0.21–0.51 and P values in the range of <0.001–<0.13 and <0.001–<0.023, respectively). Metabolic traits that correlate with growth or have a high weighting in the partial least squares regression were mainly condition specific and often related to the resource that restricts growth under that condition. Linear mixed-model analysis using the combined metabolic traits from all growth conditions as an input indicated that inclusion of random effects for the conditions improves predictions of biomass. Thus, robust prediction of biomass across a range of conditions requires condition-specific measurement of metabolic traits to take account of environment-dependent changes of the underlying networks.
Store‐operated Ca2+ entry is not required for store refilling in skeletal muscle
Authors: Cully Tanya R , Launikonis Bradley S
Published: March 2013

The present review describes store‐operated Ca2+ entry (SOCE) in skeletal muscle.

Fundamental discoveries in the field of skeletal muscle SOCE are described and the techniques that were used to make these. The advantages and limitations in these techniques are discussed to provide a means of questioning and determining the physiological role(s) of SOCE in skeletal muscle.

It is concluded that SOCE has little or no role in the filling of the sarcoplasmic reticulum with Ca2+ at rest or during a single contracture. It is likely that SOCE is activated during fatigue, although direct measurements of SOCE are lacking and the physiological significance remains uncertain.
Farmers’ Preferences for Production Practices: A Choice Experiment Study in the Rhone River Delta
Authors: Jaeck Mélanie , Lifran Robert
Published: March 2013

This article examines farmers' preferences for both cropping and management practices, which are of policy interest because of their environmental impact. We present the results of a choice experiment survey of all agricultural decision makers in the Camargue region. A latent class model identified three classes. The main class encompasses farmers complying with the norms of the Protected Geographical Indication (PGI): Riz de Camargue. We estimated the monetary value of each of the relevant agricultural practices. Our results make a strong case for differentiating incentives to encourage environmentally friendly practices and identify the diversity of values attached to the main components of rice cropping technology in the area. Estimates of the implicit prices indicate that most rice growers can be persuaded to adopt environmentally friendly practices. These findings could help in designing targeted contracts according to farmers' preferences, in line with conservation or environmental objectives.
Feasibility and outcomes of screening for cardiovascular risk factors in the emergency department
Authors: Tan Natalie , Taylor David McDonald
Published: March 2013

Objectives

The present study aimed to determine the prevalence of undiagnosed and undertreated hypercholesterolaemia and hypertension (HT) among ED patients and to evaluate the effects of a formal referral back to the general practitioner (GP) for further management.

Methods

This was a cross‐sectional study of ED patients with follow up, if indicated. Patients aged ≥35 years, without substantial illness or communication difficulties, were enrolled. Data were collected using a researcher‐administered questionnaire, a point‐of‐care Accutrend® Plus System machine (Roche Diagnostic Australia Pty Ltd, Castle Hill, NSW, Australia) and digital sphygmomanometer. Patients with total cholesterol (TC) ≥6.0 mmol/L and/or BP ≥140/90 were given a referral letter and advised to consult their GP. The investigators made follow‐up telephone calls 5 weeks later.

Results

Of 827 presentations, 534 patients were enrolled (mean age 56.7 ± 13.3 years, 300 [56.2%] male). One hundred and eleven patients (20.7%, 95% CI 17.5–24.5) had TC ≥6.0 mmol/L. Patients with/without elevated TC differed significantly (P < 0.05) in regard to age, gender, GP ownership and attendance, and previous screening. Sixty‐six patients consulted with their GP. Thirty had their TC levels retested, 18 received dietary/lifestyle advice and four had lipid‐lowering medication prescribed or adjusted. Ninety‐six patients (18.0%, 95% CI 14.9–21.6) had HT. Whereas 53 consulted their GP, no action was taken in 43 cases. Investigations were ordered for three and nine had antihypertensive medication prescribed or adjusted.

Conclusion

Substantial proportions of ED patients have undiagnosed and undertreated hypercholesterolaemia and/or HT. GP referral initiated interventions for many patients with hypercholesterolaemia, but fewer with HT. The ED has potential as a useful venue for the opportunistic screening of hypercholesterolaemia.
Blind prescribing: A study of junior doctors' prescribing preparedness in an Australian emergency department
Authors: Starmer Katrina , Sinnott Michael , Shaban Ramon , Donegan Elizabeth , Kapitzke Daniel
Published: March 2013

Objectives

The present study examined junior residents' and registrars' preparedness to prescribe in an Australian ED. It measured the medication knowledge of participants and identified antecedent factors relevant to prescribing practice.

Methods

This is a prospective, exploratory study of the prescribing practices of 40 junior doctors. Data collection consisted of a participant questionnaire with three parts. Part A comprised demographic information; Part B comprised questions regarding prescribing practices; and Part C was an objective assessment of the doctor's knowledge of the most recently and most commonly prescribed medications.

Results

One hundred percent (n = 40) of doctors in the study had inadequate knowledge about at least one medication when an accuracy threshold of <80% correct was used. Seventy percent (n = 28) of the participants had inadequate knowledge of at least one medication when the lower accuracy threshold of <50% correct was used. Comparisons between medication knowledge score and Likert confidence scales showed that even though a doctor reported being completely sure about an individual medication, they most commonly only answered between four and six of the eight questions correctly for that medication. Their use of reference materials was also lacking in relation to their knowledge and level of confidence. The reported reasons for this included instructions by senior staff and time constraints.

Conclusions

The majority of participants in the study had inadequate knowledge on medications they had most recently prescribed and medications most commonly prescribed in the ED. Junior doctors' perceptions of their medication knowledge were inflated in relation to their actual knowledge.
Effects of water temperature on development and heavy metal toxicity change in two midge species of Chironomus riparius and C. yoshimatsui in an era of rapid climate change
Authors: Mo Hyoung‐ho , Yoo DongHun , Bae Yeon Jae , Cho Kijong
Published: March 2013

Climate change is the most significant stressor that is anticipated increasingly to affect human and global ecosystems. Arthropods, including insects, are particularly vulnerable to global warming and this group is often used for various ecotoxicological tests. In addition, temperature is one of the most important toxicity‐modifying factors in ecotoxicology. Therefore, temperature dependent toxicological research is required to obtain ecologically relevant conclusions during the current era of rapid climate change. This study shows that two midge species (Chironomus riparius Meigen and C. yoshimatsui Martin et Sublette) exhibit different developmental characteristics and responses to cadmium and lead heavy metals with temperature. The former species is an internationally standardized test species in ecotoxicological studies, whereas the latter species is native to Korea. Hence, even though these two species belong to the same genus, Chironomus, their development differs with temperature, which leads to different responses to heavy metals. There was a decline in developmental time (from egg and larva to pupa) for both species with temperature; however, there was a species difference in the rate of decline. In the acute toxicity test, the 48‐hr LC50 values for cadmium and lead decreased with temperature for both species. In the chronic toxicity test, emergence rates tended to decrease with temperature, except for when C. yoshimatsui was exposed to cadmium.
Adaptive morphology of the heart of Southern‐Fur‐Seal (Arctocephalus australis– Zimmermamm, 1783)
Authors: Guimarães Juliana P. , Mari Renata B. , Le Bas Alfredo , Watanabe Ii‐Sei
Published: March 2013

The Southern‐fur‐seal belongs to the order Carnivora, suborder Pinnipedia, and Otariidae family. This species inhabits aquatic and terrestrial environments, thus presenting important morphophysiological adaptive changes, especially in the cardiac system. For this purpose, Southern‐fur‐seal (Arctocephalus australis) hearts were used from animals that died from natural causes. Gross morphology observations were supported by light, scanning and transmission electron microscopy. The heart was long and flat; it was lined by pericardium and partly covered by lungs. Structurally, atrium and ventricle muscle fibers exhibit typical features of cardiac fibers revealing myofibrils bundles, mitochondria, plate‐shaped junctions, anastomosis between myofibrils bundles, and electron‐dense granule natriuretic around the nucleus and mitochondria of atrium muscle cells. The Southern‐fur‐seal heart was structurally similar to other mammals; however, it presented morphological changes that assist in their adaptation to their environment.
Kolaviron, a Natural Antioxidant and Anti‐Inflammatory Phytochemical Prevents Dextran Sulphate Sodium‐Induced Colitis in Rats
Authors: Farombi Ebenezer O. , Adedara Isaac A. , Ajayi Babajide O. , Ayepola Omolola R. , Egbeme Ewomazino E.
Published: March 2013

The beneficial effects of kolaviron, a natural biflavonoid from the seeds of Garcinia kola, have been attributed mainly to its antioxidant and anti‐inflammatory effects. This study investigated these effects on dextran sulphate sodium (DSS)‐induced ulcerative colitis in rats. Sulfasalazine served as standard reference in this study. Kolaviron and sulfasalazine were separately co‐administered orally at 200 mg/kg and 500 mg/kg, respectively, to dextran sulphate sodium‐exposed rats for 5 days. The result indicated that kolaviron or sulfasalazine significantly prevented DSS‐induced body weight loss as well as the incidence of diarrhoea and bleeding in DSS‐exposed rats. Kolaviron suppressed the DSS‐mediated increase in colonic nitric oxide concentration and myeloperoxidase activity and significantly prevented the increase in inflammatory mediators, interleukin‐1β and tumour necrosis factor alpha, in the colon of DSS‐treated rats. The significant depletion in colonic antioxidant status in rats exposed to DSS alone was evident by marked reduction in colonic catalase and glutathione S‐transferase activities as well as glutathione content, leading to elevated hydrogen peroxide and lipid peroxidation levels. Histopathologically, DSS alone resulted in severe epithelial erosion, total absence of goblet cells, destruction of the crypts, necrotic and distorted glands, accompanied by marked cellular mononuclear cells infiltration. However, administration of kolaviron and sulfasalazine ameliorated DSS‐induced colitis by increasing the antioxidant status decreased hydrogen peroxide and lipid peroxidation levels and attenuated the adverse effect of DSS on colon architecture. In conclusion, the anti‐colitis effect of kolaviron is related to its intrinsic anti‐inflammatory and anti‐oxidative properties.
Metformin Induces Cytotoxicity by Down‐Regulating Thymidine Phosphorylase and Excision Repair Cross‐Complementation 1 Expression in Non‐Small Cell Lung Cancer Cells
Authors: Ko Jen‐Chung , Huang Yu‐Ching , Chen Huang‐Jen , Tseng Sheng‐Chieh , Chiu Hsien‐Chun , Wo Ting‐Yu , Huang Yi‐Jhen , Weng Shao‐Hsing , Chiou Robin Y. Y. , Lin Yun‐Wei
Published: March 2013

Metformin is an antidiabetic drug recently shown to inhibit cancer cell proliferation and growth, although the involved molecular mechanisms have not been elucidated. In many cancer cells, high expression of thymidine phosphorylase (TP) and Excision repair cross‐complementation 1 (ERCC1) is associated with poor prognosis. We used A549 and H1975 human non‐small cell lung cancer (NSCLC) cell lines to investigate the role of TP and ERCC1 expression in metformin‐induced cytotoxicity. Metformin treatment decreased cellular TP and ERCC1 protein and mRNA levels by down‐regulating phosphorylated MEK1/2‐ERK1/2 protein levels in a dose‐ and time‐dependent manner. The enforced expression of the constitutively active MEK1 (MEK1‐CA) vectors significantly restored cellular TP and ERCC1 protein levels and cell viability. Specific inhibition of TP and ERCC1 expression by siRNA enhanced the metformin‐induced cytotoxicity and growth inhibition. Arachidin‐1, an antioxidant stilbenoid, further decreased TP and ERCC1 expression and augmented metformin's cytotoxic effect, which was abrogated in lung cancer cells transfected with MEK1/2‐CA expression vector. In conclusion, metformin induces cytotoxicity by down‐regulating TP and ERCC1 expression in NSCLC cells.
Dexamethasone‐eluting Vascular Stents
Authors: Hämäläinen Mari , Nieminen Riina , Uurto Ilkka , Salenius Juha‐Pekka , Kellomäki Minna , Mikkonen Joonas , Kotsar Andres , Isotalo Taina , LJ Teuvo Tammela , Talja Martti , Moilanen Eeva
Published: March 2013

Percutaneous transluminal angioplasty (PTA) with stenting is widely used in the treatment of vascular disorders, but restenosis remains a significant problem. Drug‐eluting stents (DES) have been developed as an attempt to reduce the intimal response leading to restenosis. Drugs used in DES include mainly immunosuppressive and anti‐proliferative compounds. Glucocorticoids are also an interesting possibility for those purposes because they have anti‐proliferative effects in vascular smooth muscle cells and down‐regulate the production of cytokines and growth factors driving inflammation and fibrosis. In this MiniReview, feasibility and safety of drug‐eluting metal and biodegradable vascular stents are discussed with special emphasis on dexamethasone‐eluting stents.
Recent, very rapid retreat of a temperate glacier in SE Iceland
Authors: Bradwell Tom , Sigurđsson Oddur , Everest Jez
Published: March 2013

Iceland's glaciers are particularly sensitive to climate change, and their margins respond to trends in air temperature. Most Icelandic glaciers have been in retreat since c. 1990, and almost all since 1995. Using ice‐front measurements, photographic and geomorphological evidence, we examined the record of ice‐front fluctuations of Virkisjökull–Falljökull, a steep high‐mass‐turnover outlet glacier in maritime SE Iceland, in order to place recent changes in a longer‐term (80‐year) context. Detailed geomorphological mapping identifies two suites of annual push moraines: one suite formed between c. 1935 and 1945, supported by lichenometric dating; the other between 1990 and 2004. Using moraine spacing as a proxy for ice‐front retreat rates, we show that average retreat rates during the 1930s and 1940s (28 m a−1) were twice as high as during the period from 1990 to 2004 (14 m a−1). Furthermore, we show that both suites of annual moraines are associated with above‐average summer temperatures. Since 2005, however, retreat rates have increased considerably – averaging 35 m a−1 – with the last 5 years representing the greatest amount of ice‐front retreat (∼190 m) in any 5‐year period since measurements began in 1932. We propose that this recent, rapid, ice‐front retreat and thinning in a decade of unusually warm summers has resulted in a glaciological threshold being breached, with subsequent large‐scale stagnation of the glacier terminus (i.e. no forward movement) and the cessation of annual push‐moraine formation. Breaching this threshold has, we suggest, caused further very rapid non‐uniform retreat and downwasting since 2005 via a system feedback between surface melting, glacier thinning, decreased driving stress and decreased forward motion.