bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular Characterization of a Heterothallic Mating System in Pseudogymnoascus destructans, the Fungus Causing White-Nose Syndrome of Bats
Authors: Palmer Jonathan M , Kubatova Alena , Novakova Alena , Minnis Andrew M , Kolarik Miroslav , Lindner Daniel L 
Published: July 2014

Abstract
White-nose syndrome (WNS) of bats has devastated bat populations in eastern North America since its discovery in 2006. WNS, caused by the fungus Pseudogymnoascus destructans, has spread quickly in North America and has become one of the most severe wildlife epidemics of our time. While P. destructans is spreading rapidly in North America, nothing is known about the sexual capacity of this fungus. To gain insight into the genes involved in sexual reproduction, we characterized the mating-type locus (MAT) of two Pseudogymnoascus spp. that are closely related to P. destructans and homothallic (self-fertile). As with other homothallic Ascomycota, the MAT locus of these two species encodes a conserved α-box protein (MAT1-1-1) as well as two high-mobility group (HMG) box proteins (MAT1-1-3 and MAT1-2-1). Comparisons with the MAT locus of the North American isolate of P. destructans (the ex-type isolate) revealed that this isolate of P. destructans was missing a clear homolog of the conserved HMG box protein (MAT1-2-1). These data prompted the discovery and molecular characterization of a heterothallic mating system in isolates of P. destructans from the Czech Republic. Both mating types of P. destructans were found to coexist within hibernacula, suggesting the presence of mating populations in Europe. Although populations of P. destructans in North America are thought to be clonal and of one mating type, the potential for sexual recombination indicates that continued vigilance is needed regarding introductions of additional isolates of this pathogen.
Asymmetric Neuroblast Divisions Producing Apoptotic Cells Require the Cytohesin GRP-1 in Caenorhabditis elegans
Authors: Teuliere Jerome , Cordes Shaun , Singhvi Aakanksha , Talavera Karla , Garriga Gian 
Published: July 2014

Abstract
Cytohesins are Arf guanine nucleotide exchange factors (GEFs) that regulate membrane trafficking and actin cytoskeletal dynamics. We report here that GRP-1, the sole Caenorhabditis elegans cytohesin, controls the asymmetric divisions of certain neuroblasts that divide to produce a larger neuronal precursor or neuron and a smaller cell fated to die. In the Q neuroblast lineage, loss of GRP-1 led to the production of daughter cells that are more similar in size and to the transformation of the normally apoptotic daughter into its sister, resulting in the production of extra neurons. Genetic interactions suggest that GRP-1 functions with the previously described Arf GAP CNT-2 and two other Arf GEFs, EFA-6 and BRIS-1, to regulate the activity of Arf GTPases. In agreement with this model, we show that GRP-1’s GEF activity, mediated by its SEC7 domain, is necessary for the posterior Q cell (Q.p) neuroblast division and that both GRP-1 and CNT-2 function in the Q.posterior Q daughter cell (Q.p) to promote its asymmetry. Although functional GFP-tagged GRP-1 proteins localized to the nucleus, the extra cell defects were rescued by targeting the Arf GEF activity of GRP-1 to the plasma membrane, suggesting that GRP-1 acts at the plasma membrane. The detection of endogenous GRP-1 protein at cytokinesis remnants, or midbodies, is consistent with GRP-1 functioning at the plasma membrane and perhaps at the cytokinetic furrow to promote the asymmetry of the divisions that require its function.
Handling Large and Complex Data in a Photovoltaic Research Institution Using a Custom Laboratory Information Management System
Authors: White Robert R. , Munch Kristin 
Published: July 2014

ABSTRACTTwenty-five years ago the desktop computer started becoming ubiquitous in the scientific lab. Researchers were delighted with its ability to both control instrumentation and acquire data on a single system, but they were not completely satisfied. There were often gaps in knowledge that they thought might be gained if they just had more data and they could get the data faster. Computer technology has evolved in keeping with Moore’s Law meeting those desires; however those improvements have of late become both a boon and bane for researchers. Computers are now capable of producing high speed data streams containing terabytes of information; capabilities that evolved faster than envisioned last century. Software to handle large scientific data sets has not kept up. How much information might be lost through accidental mismanagement or how many discoveries are missed through data overload are now vital questions. An important new task in most scientific disciplines involves developing methods to address those issues and to create the software that can handle large data sets with an eye towards scalability. This software must create archived, indexed, and searchable data from heterogeneous instrumentation for the implementation of a strong data-driven materials development strategy. At the National Center for Photovoltaics in the National Renewable Energy Laboratory, we began development a few years ago on a Laboratory Information Management System (LIMS) designed to handle lab-wide scientific data acquisition, management, processing and mining needs for physics and materials science data, and with a specific focus towards future scalability for new equipment or research focuses. We will present the decisions, processes, and problems we went through while building our LIMS system for materials research, its current operational state and our steps for future development.
Ab Initio Study of the Sub-threshold Electron Transport Properties of Ultra-scaled Amorphous Phase Change Material Germanium Telluride
Authors: Liu Jie , Xu Xu , Anantram M. P. 
Published: July 2014

ABSTRACTThe sub-threshold electron transport properties of amorphous (a-) germanium telluride (GeTe) phase change material (PCM) ultra-thin films are investigated by using ab initio molecular dynamics, density function theory, and Green’s function simulations. The simulation results reproduce the trends in measured electron transport properties, e.g. current-voltage curve, intra-bandgap donor-like and acceptor-like defect states, and p-type conductivity. The underlying physical mechanism of electron transport in ultra-scaled a-PCM is unraveled. We find that, though the current-voltage curve of the ultra-scaled a-PCM resembles that of the bulk a-PCM, their physical origins are different. Unlike the electron transport in bulk a-PCM, which is governed by the Poole-Frenkel effect, the electron transport in ultra-scaled a-PCM is largely dominated by tunneling transport via intra-bandgap donor-like and acceptor-like defect states.
Near-UV background as a bridge between visible and infrared communication
Authors: Vieira M. , Vieira M. A. , Silva V. , Rodrigues I. , Louro P. 
Published: July 2014

ABSTRACTIn this paper we present a monolithically integrated wavelength selector based on a multilayer pi’n/pin a-SiC:H integrated optical filter that requires appropriate near-ultraviolet steady states optical switches to select the desired wavelengths in the VIS-NIR ranges.Results show that the background intensity works as a selector in the infrared/visible regions, shifting the sensor sensitivity. Low intensities select the NIR range while high intensities select the visible part accordingly to its wavelength. Here, the optical gain is very high in the red range, decreases in the green range, and stays near one in the blue region decreasing strongly in the near-UV range. The transfer characteristics effects due to changes in steady state light intensity and wavelength backgrounds are presented. The relationship between the optical inputs and the output signal is established when a multiplexed signal is analyzed.
Femtosecond laser materials processing of a-Si:H below the ablation threshold
Authors: Soleymanzadeh B. , Beyer W. , Luekermann F. , Prunici P. , Pfeiffer W. , Stiebig H. 
Published: July 2014

ABSTRACTLaser processing of thin-film silicon is a promising approach for the realization of polycrystalline silicon for large area electronics and solar cell applications. In this study we investigate the material modification of amorphous hydrogenated silicon (a-Si:H) with different hydrogen content (30%, 13% and <1%) by means of femtosecond (fs) laser pulses. Depending on the peak fluence applied, hydrogen diffusion/effusion, layer crystallization or material ablation can be achieved. Despite the low absorption coefficient of a-Si:H at the center wavelength of an amplified Titanium Sapphire laser at 790 nm a high local energy deposition close to the surface of the a-Si:H layer is observed, which can be attributed to a nonlinear absorption process.
Crystallization of Amorphous Silicon and Dopant Activation using Xenon Flash-Lamp Annealing (FLA)
Authors: Mudgal T. , Reepmeyer C. , Manley R. G. , Cormier D. , Hirschman K.D. 
Published: July 2014

ABSTRACTFlash-lamp annealing (FLA) has been investigated for the crystallization of a 60 nm amorphous silicon (a-Si) layer deposited by PECVD on display glass. Input factors to the FLA system included lamp intensity and pulse duration. Conditions required for crystallization included use of a 100 nm SiO2capping layer, and substrate heating resulting in a surface temperature ∼ 460 °C. An irradiance threshold of ∼ 20 kW/cm2was established, with successful crystallization achieved at a radiant exposure of 5 J/cm2, as verified using variable angle spectroscopic ellipsometry (VASE) and Raman spectroscopy. Nickel-enhanced crystallization (NEC) using FLA was also investigated, with results suggesting an increase in crystalline volume. Different combinations of furnace annealing and FLA were studied for crystallization and activation of samples implanted with boron and phosphorus. Boron activation demonstrated a favorable response to FLA, achieving a resistivity ρ < 0.01 Ω•cm. Phosphorus activation by FLA resulted in a resistivity ρ ∼ 0.03 Ω•cm.
Effect of Morphology-based Defect Structure of ZnO Nanostructures in Photo-Degradation of Organic Dye
Authors: Shidpour Reza , Vosoughi Manouchehr , Simchi Abdolreza , Ghanbari Faegheh 
Published: July 2014

ABSTRACTThe fabrication of strong photocatalysts applied to the degradation of organic pollutants is necessary in environmental applications. In a single-stage method, acetate precursor and poly vinyl pyrolydine are used to produce ZnO nanostructures with various morphologies in annealing temperatures ranging from 300 °C to 900 oC. The physical properties of the prepared nanostructures were characterized by SEM, XRD and PL spectroscopy. The SEM images exhibit a variety of the as-prepared hexagonal zinc oxides including wires, rods, particles and porous network of welded particles of ZnO nanoparticles. The results of the photocatalytic degradation of methylene blue as an organic dye in aqueous suspension showed that the morphology of ZnO nanostructures influences on the photocatalytic efficiency of ZnO nanostructures, greatly. For the best result, the highest MB degradation occurs by ZnO nanowires within 16 minutes and in others samples, degradation of higher than 95 percent occurs within 20 minutes. The XRD and PL spectroscopy revealed neither VZn nor Oi are in all of samples but only VO−, VO2− and Zni exist in ZnO nanostructures.
Simulation of Charge Transport in Disordered Assemblies of Metallic Nano-Islands: Application to Boron-Nitride Nanotubes Functionalized with Gold Quantum Dots
Authors: Jaszczak John A. , Savaikar Madhusudan A. , Banyai Douglas R. , Hao Boyi , Zhang Dongyan , Bergstrom Paul L. , Li An-Ping , Idrobo Juan-Carlos , Yap Yoke Khin 
Published: July 2014

ABSTRACTIn this study, we investigate the charge-transport behavior in a disordered one-dimensional (1D) chain of metallic islands using the newly developed multi-island transport simulator (MITS) based on semi-classical tunneling theory and kinetic Monte Carlo simulation. The 1D chain is parameterized to model the experimentally-realized devices studied by Lee et al. [Advanced Materials25, 4544-4548 (2013)], which consists of nano-meter-sized gold islands randomly deposited on an insulating boron-nitride nanotube. These devices show semiconductorlike behavior without having semiconductor materials. The effects of disorder, device length, temperature, and source-drain bias voltage (VSD) on the current are examined. Preliminary results of random assemblies of gold nano-islands in two dimensions (2D) are also examined in light of the 1D results.At T = 0 K and low source-drain bias voltages, the disordered 1D-chain device shows charge-transport characteristics with a well-defined Coulomb blockade (CB) and Coulomb staircase (CS) features that are manifestations of the nanometer size of the islands and their separations. In agreement with experimental observations, the CB and the blockade threshold voltage (Vth) at which the device begins to conduct increases linearly with increasing chain length. The CS structures are more pronounced in longer chains, but disappear at high VSD. Due to tunneling barrier suppression at high bias, the current-voltage characteristics for VSD > Vth follow a non-linear relationship. Smaller islands have a dominant effect on the CB and Vth due to capacitive effects. On the other hand, the wider junctions with their large tunneling resistances predominantly determine the overall device current. This study indicates that smaller islands with smaller inter-island spacings are better suited for practical applications. Temperature has minimal effects on high-bias current behavior, but the CB is diminished as Vth decreases with increasing temperature.In 2D systems with sufficient disorder, our studies demonstrate the existence of a dominant conducting path (DCP) along which most of the current is conveyed, making the device effectively quasi-1-dimensional. The existence of a DCP is sensitive to the device structure, but can be robust with respect to changes in VSD.
In-situ annealing of self-ion irradiation damage in tungsten
Authors: Yi Xiaoou. , Jenkins Michael L. , Roberts Steve G. , Kirk Marquis A. 
Published: July 2014

ABSTRACTIn our earlier work [1] microstructural evolution in tungsten under self-ion irradiation was investigated as a function of temperature and dose by in-situ 150 keV W+ ion irradiations on the IVEM-Tandem facility at Argonne National Laboratory (ANL). The present work focuses on the thermal stability of this damage. Thin foils of tungsten were irradiated at room temperature (R.T.) to fluences up to 1018 W+m-2 (∼ 1.0 dpa) and were then annealed in-situ for up to 120 min at temperatures between 300 and 800°C.We found that: (1) loops with Burgers vectors ½ <111> and <100> coexist during annealing; (2) <100> is not a stable loop configuration above 300°C and the fraction of such loops decreased with increasing temperature and/or time; (3) changes in loop populations during annealing were very sensitive to temperature, but less sensitive to time. The majority of changes occurred within 15 min, and were associated with the loss of small (1-2 nm) dislocation loops. The origin of these trends is discussed by considering defect mobility and the energetics of defect configurations predicted by previous DFT calculations [2].
Low Temperature Metal Organic Chemical Vapor Deposition of Aluminum Oxide Thin Films for Advanced CMOS Gate Dielectric Applications
Authors: Skordas Spyridon , Papadatos Filippos , Patel Zubin , Nuesca Guillermo , Eisenbraun Eric , Gusev Evgeni , Kaloyeros Alain E. 
Published: July 2014

AbstractA low-temperature metal organic chemical vapor deposition (MOCVD) process for the growth of aluminum oxide for gate dielectric applications has been developed. Amorphous films were deposited on 200-mm Si(100) wafers, employing an Al β-diketonate precursor [Al(III) 2,4-pentanedionate] and H2O. Chemical and microstructural properties of films grown in a temperature range of 250-450°C were studied using x-ray photo-electron spectroscopy (XPS), xray diffraction (XRD), Rutherford back-scattering spectrometry (RBS), nuclear reaction analysis (NRA), cross-sectional (X) scanning and transmission electron microscopy (XSEM and XTEM). A design of experiment (DOE) method was used for process mapping and optimization. An optimized process window was defined for the growth of dense, amorphous films with carbon and hydrogen inclusion as low as 1 at. % and 3 at. % respectively. Post-deposition annealing studies indicated that chemical and structural film properties are generally stable up to 650°C. The electrical performance of the films was evaluated by capacitance-voltage (C-V) and currentvoltage (I-V) measurements on metal-oxide-semiconductor (MOS) structures. The dielectric constant (k) obtained was 6.7-9.6 (depending on annealing conditions), with equivalent oxide thickness (EOT) as low as 1.3 nm. Leakage current densities lower than that of equivalent SiO2 films were also achieved.
A Silicon-Based Infra-Red Photodetector Exploiting Erbium-Doped Silicon Nanocrystals
Authors: Kenyon Anthony J. , Bhamber Sukhvinder S. , Pitt Christopher W. 
Published: July 2014

AbstractWe have exploited the interaction between erbium ions and silicon nanoclusters to produce a photodetector for use in the spectral region around 1.5 μm. The device consists of an MOS structure in which the oxide layer has been implanted with both erbium and silicon and annealed to produce silicon nanocrystals around 3 nm in diameter. Upon illumination with a 1480 nm laser diode, the well-known interaction between the nanocrystals and the rare-earth ions results in a transfer of excitation from the erbium ion to nearby silicon nanocrystals. The resultant modification of the conductivity of the oxide layer enables a current to flow when a voltage is applied.
Electrochemical Synthesis of Molybdenum Oxide Thin Films: Deposition Mechanism and Template-Directed Assembly of Nanostructured Materials and Components
Authors: McEvoy Todd M. , Celio Hugo , Barton Emily E. , Stevenson Keith J. 
Published: July 2014

AbstractWe describe the electrochemical deposition of molybdenum oxide thin films prepared from aqueous solutions containing peroxo-poly and oxometallate complexes of molybdenum(VI). Electrochemical quartz crystal microgravimetry (EQCM) was used to establish corresponding reaction mechanisms for films grown at different deposition potentials. Electrodeposition from acidified sodium molybdate solutions proceeds by the reduction of molybdic acid; whilst deposition from aqueous peroxo-based solutions involves the graded reduction of several solution components, primarily comprising molybdic acid and peroxopolymolybdates. Films grown from acidified sodium molybdate solutions are weakly adherent and easily rinsed off, while those grown from peroxo-polymolybdate solutions are strongly attached and stable. Careful regulation of the deposition potential allows for controlled growth of distinct molybdenum oxide compositions to produce films with varied water content and valency. Electrochemical deposition through sacrificial colloidal-crystal templates is also demonstrated to prepare macroporous thin films comprising hexagonally close-packed arrays of spherical pores.
Mapping the nursing care with the NIC for patients in risk for pressure ulcer
Authors: Pereira Ana Gabriela Silva , Santos Cássia Teixeira dos , Menegon Dóris Baratz , Mello Bruna Schroeder , Azambuja Fernanda , Lucena Amália de Fátima 
Published: July 2014

Objective:To identify the nursing care prescribed for patients in risk for pressure ulcer (PU) and to compare those with the Nursing Interventions Classification (NIC) interventions. Method: Cross mapping study conducted in a university hospital. The sample was composed of 219 adult patients hospitalized in clinical and surgical units. The inclusion criteria were: score ≤ 13 in the Braden Scale and one of the nursing diagnoses, Self-Care deficit syndrome, Impaired physical mobility, Impaired tissue integrity, Impaired skin integrity, Risk for impaired skin integrity. The data were collected retrospectively in a nursing prescription system and statistically analyzed by crossed mapping. Result: It was identified 32 different nursing cares to prevent PU, mapped in 17 different NIC interventions, within them: Skin surveillance, Pressure ulcer prevention and Positioning. Conclusion: The cross mapping showed similarities between the prescribed nursing care and the NIC interventions.
Assessing leaf spectral properties of Phragmites australis impacted by acid mine drainage
Authors: Van Deventer Heidi , Cho Moses A. 
Published: July 2014

The decanting of acid mine drainage (AMD) from the Western Basin on the Witwatersrand in late 2010 raised concerns about AMD risks in other gold, coal and copper mining areas of South Africa. Field spectroscopy and the use of vegetation indices could offer an affordable and easy means of monitoring the impact of mine water and/or AMD on vegetation. The impact of raw and treated mine water or contaminated soil on wetland vegetation often manifests in growth inhibition and reduction of foliar pigments and nutrient levels. Surveying the impact on wetland vegetation or underlying soils can be difficult and expensive considering the cost of laboratory analysis of samples. The potential of field spectroscopy for detecting the impact of mine water on wetland vegetation was examined by assessing (1) whether there was a significant difference in leaf spectra between sites receiving mine water and a non-impacted control site and (2) whether there was a gradation of vegetation condition downstream from the decanting site. Two vegetation indices were derived from portable field spectrometer-measured spectra of five green leaves of Phragmites australis – the chlorophyll red edge position (REP) and the normalised difference vegetation index (NDVI) – for two dormant (winter) and peak growth (summer) seasons in 2011–2012. Mean REP and NDVI values were significantly (p<0.05) lower for affected sites compared to the control site for both seasons and years. The range of REP values for young green leaves in winter for affected sites was 695–720 nm compared to the narrower range of 705–721 nm for the control site. The mean REP values for young green leaves in winter was 708 nm for the affected sites compared to 716 nm for the control site. The downstream gradation, however, fluctuated for REP and NDVI over the study period. We conclude that field spectroscopy shows potential to serve as a relatively quick and affordable means to assess the condition and health of vegetation affected by AMD.