bluuebunny/crossref_metadata_2025_split huggingface dataset:
Metabolic engineering of Caldicellulosiruptor bescii yields increased hydrogen production from lignocellulosic biomass
Authors: Cha Minseok , Chung Daehwan , Elkins James G , Guss Adam M , Westpheling Janet 
Published: June 2013

Abstract

Background
Members of the anaerobic thermophilic bacterial genus Caldicellulosiruptor are emerging candidates for consolidated bioprocessing (CBP) because they are capable of efficiently growing on biomass without conventional pretreatment. C. bescii produces primarily lactate, acetate and hydrogen as fermentation products, and while some Caldicellulosiruptor strains produce small amounts of ethanol C. bescii does not, making it an attractive background to examine the effects of metabolic engineering. The recent development of methods for genetic manipulation has set the stage for rational engineering of this genus for improved biofuel production. Here, we report the first targeted gene deletion, the gene encoding lactate dehydrogenase (ldh), for metabolic engineering of a member of this genus.

Results
A deletion of the C. bescii L-lactate dehydrogenase gene (ldh) was constructed on a non-replicating plasmid and introduced into the C. bescii chromosome by marker replacement. The resulting strain failed to produce detectable levels of lactate from cellobiose and maltose, instead increasing production of acetate and H2 by 21-34% relative to the wild type and ΔpyrFA parent strains. The same phenotype was observed on a real-world substrate – switchgrass (Panicum virgatum). Furthermore, the ldh deletion strain grew to a higher maximum optical density than the wild type on maltose and cellobiose, consistent with the prediction that the mutant would gain additional ATP with increased acetate production.

Conclusions
Deletion of ldh in C. bescii is the first use of recently developed genetic methods for metabolic engineering of these bacteria. This deletion resulted in a redirection of electron flow from production of lactate to acetate and hydrogen. New capabilities in metabolic engineering combined with intrinsic utilization of lignocellulosic materials position these organisms to provide a new paradigm for consolidated bioprocessing of fuels and other products from biomass.
The Effects of Symptom Recognition and Diagnostic Labels on Public Beliefs, Emotional Reactions, and Stigmas Associated with Intellectual Disability
Authors: Scior Katrina , Connolly Theresa , Williams Janice 
Published: June 2013

Abstract
Labels are firmly rejected by the disability rights movement, yet the complex effects of labeling on lay beliefs are poorly understood. This study examined the effects of labeling on the general public's reactions to people with intellectual disabilities. A sample of 1,233 adult members of the UK general population were randomly presented with either a diagnostically labeled or unlabeled case vignette, and their emotional reactions, causal beliefs, and social distance were assessed. Providing a label reduced social distance, increased biomedical attributions, and had a small positive direct effect on emotional reactions. Making a diagnosis of mild intellectual disability known may prevent misattribution to more stigmatizing causes and thus reduce social distance. Some undesirable effects were observed though on causal beliefs and associated emotional reactions.
Structure and Dielectric Properties of Pure and Zinc Oxide-Doped Barium Titanate
Authors: Hasan M. M. , Shorowordi K. M. 
Published: June 2013

Abstract
The effects of zinc oxide addition and sintering parameters on the structure and dielectric properties of barium titanate are observed. Different percentage of ZnO ranging from 0.30 to 1 wt. % is doped in barium titanate. Both the doped and undoped samples are sintered at temperatures ranging from 1250°C to 1325°C at different soaking times. The amount of densification of the doped and undoped samples is measured in terms of percentage theoretical density. Grain size and microstructural analysis is performed by a scanning electron microscope (SEM). Lattice parameters and tetragonality of doped and undoped barium titanate are calculated from x-ray diffraction pattern obtained from x-ray diffractometer (XRD) test. Dielectric properties of the samples are measured by an impedance analyzer. It is found that all the doped samples obtain their maximum percentage theoretical density at a lower sintering temperature compared to the undoped sample. SEM study reveals that the doped samples always show smaller grains compared to the undoped sample. Significant grain growth is observed in all of the samples at sintering temperatures above 1300°C. The evidence of surface melting is observed in 1 wt. % ZnO-doped sample soaked at 1325°C for 2 h. The presence of liquid at that sintering condition is explained by the doping mechanism of Zn2+ in BaTiO3. Correlation among the grain size, tetragonality, and dielectric properties of the doped and undoped samples are also discussed.
Unexpected Role for Dosage Compensation in the Control of Dauer Arrest, Insulin-Like Signaling, and FoxO Transcription Factor Activity inCaenorhabditis elegans
Authors: Dumas Kathleen J , Delaney Colin E , Flibotte Stephane , Moerman Donald G , Csankovszki Gyorgyi , Hu Patrick J 
Published: June 2013

AbstractDuring embryogenesis, an essential process known as dosage compensation is initiated to equalize gene expression from sex chromosomes. Although much is known about how dosage compensation is established, the consequences of modulating the stability of dosage compensation postembryonically are not known. Here we define a role for the Caenorhabditis elegans dosage compensation complex (DCC) in the regulation of DAF-2 insulin-like signaling. In a screen for dauer regulatory genes that control the activity of the FoxO transcription factor DAF-16, we isolated three mutant alleles of dpy-21, which encodes a conserved DCC component. Knockdown of multiple DCC components in hermaphrodite and male animals indicates that the dauer suppression phenotype of dpy-21 mutants is due to a defect in dosage compensation per se. In dpy-21 mutants, expression of several X-linked genes that promote dauer bypass is elevated, including four genes encoding components of the DAF-2 insulin-like pathway that antagonize DAF-16/FoxO activity. Accordingly, dpy-21 mutation reduced the expression of DAF-16/FoxO target genes by promoting the exclusion of DAF-16/FoxO from nuclei. Thus, dosage compensation enhances dauer arrest by repressing X-linked genes that promote reproductive development through the inhibition of DAF-16/FoxO nuclear translocation. This work is the first to establish a specific postembryonic function for dosage compensation in any organism. The influence of dosage compensation on dauer arrest, a larval developmental fate governed by the integration of multiple environmental inputs and signaling outputs, suggests that the dosage compensation machinery may respond to external cues by modulating signaling pathways through chromosome-wide regulation of gene expression.
Rates and Genomic Consequences of Spontaneous Mutational Events inDrosophila melanogaster
Authors: Schrider Daniel R , Houle David , Lynch Michael , Hahn Matthew W 
Published: June 2013

AbstractBecause spontaneous mutation is the source of all genetic diversity, measuring mutation rates can reveal how natural selection drives patterns of variation within and between species. We sequenced eight genomes produced by a mutation-accumulation experiment in Drosophila melanogaster. Our analysis reveals that point mutation and small indel rates vary significantly between the two different genetic backgrounds examined. We also find evidence that ∼2% of mutational events affect multiple closely spaced nucleotides. Unlike previous similar experiments, we were able to estimate genome-wide rates of large deletions and tandem duplications. These results suggest that, at least in inbred lines like those examined here, mutational pressures may result in net growth rather than contraction of the Drosophila genome. By comparing our mutation rate estimates to polymorphism data, we are able to estimate the fraction of new mutations that are eliminated by purifying selection. These results suggest that ∼99% of duplications and deletions are deleterious—making them 10 times more likely to be removed by selection than nonsynonymous mutations. Our results illuminate not only the rates of new small- and large-scale mutations, but also the selective forces that they encounter once they arise.
Religious Exemptions for Immunization and Risk of Pertussis in New York State, 2000–2011
Authors: Imdad Aamer , Tserenpuntsag Boldtsetseg , Blog Debra S. , Halsey Neal A. , Easton Delia E. , Shaw Jana 
Published: June 2013

OBJECTIVE:
The objective of this study was to describe rates of religious vaccination exemptions over time and the association with pertussis in New York State (NYS).

METHODS:
Religious vaccination exemptions reported via school surveys of the NYS Department of Health from 2000 through 2011 were reviewed by county, and the changes were assessed against incidence rates of pertussis among children reported to the NYS Department of Health Communicable Disease Electronic Surveillance System.

RESULTS:
The overall annual state mean prevalence (± SD) of religious exemptions for ≥1 vaccines in 2000–2011 was 0.4% ± 0.08% and increased significantly from 0.23% in 2000 to 0.45% in 2011 (P = .001). The prevalence of religious exemptions varied greatly among counties and increased by &gt;100% in 34 counties during the study period. Counties with mean exemption prevalence rates of ≥1% reported a higher incidence of pertussis, 33 per 100 000 than counties with lower exemption rates, 20 per 100 000, P &lt; .001. In addition, the risk of pertussis among vaccinated children living in counties with high exemption rate increased with increase of exemption rate among exempted children (P = .008).

CONCLUSIONS:
The prevalence of religious exemptions varies among NYS counties and increased during the past decade. Counties with higher exemption rates had higher rates of reported pertussis among exempted and vaccinated children when compared with the low-exemption counties. More studies are needed to characterize differences in the process of obtaining exemptions among NYS schools, and education is needed regarding the risks to the community of individuals opting out from recommended vaccinations.
Trends in Bronchiolitis Hospitalizations in the United States, 2000–2009
Authors: Hasegawa Kohei , Tsugawa Yusuke , Brown David F.M. , Mansbach Jonathan M. , Camargo Carlos A. 
Published: June 2013

OBJECTIVE:
To examine temporal trend in the national incidence of bronchiolitis hospitalizations, use of mechanical ventilation, and hospital charges between 2000 and 2009.

METHODS:
We performed a serial, cross-sectional analysis of a nationally representative sample of children hospitalized with bronchiolitis. The Kids Inpatient Database was used to identify children &lt;2 years of age with bronchiolitis by International Classification of Diseases, Ninth Revision, Clinical Modification code 466.1. Primary outcome measures were incidence of bronchiolitis hospitalizations, mechanical ventilation (noninvasive or invasive) use, and hospital charges. Temporal trends were evaluated accounting for sampling weights.

RESULTS:
The 4 separated years (2000, 2003, 2006, and 2009) of national discharge data included 544 828 weighted discharges with bronchiolitis. Between 2000 and 2009, the incidence of bronchiolitis hospitalization decreased from 17.9 to 14.9 per 1000 person-years among all US children aged &lt;2 years (17% decrease; Ptrend &lt; .001). By contrast, there was an increase in children with high-risk medical conditions (5.9%–7.9%; 34% increase; Ptrend &lt; .001) and use of mechanical ventilation (1.9%–2.3%; 21% increase; Ptrend = .008). Nationwide hospital charges increased from $1.34 billion to $1.73 billion (30% increase; Ptrend &lt; .001); this increase was driven by a rise in the geometric mean of hospital charges per case from $6380 to $8530 (34% increase; Ptrend &lt; .001).

CONCLUSIONS:
Between 2000 and 2009, we found a significant decline in bronchiolitis hospitalizations among US children. By contrast, use of mechanical ventilation and hospital charges for bronchiolitis significantly increased over this same period.
Growth of Carbon Nanotubes on Mesoporous Silica Coated Planar and Three-Dimensional Surfaces
Authors: Staggemeier Katrina , Ke Jin , Downard Alison , Golovko Vladimir , Chopra Nitin , Bakker Martin G. 
Published: June 2013

ABSTRACTWell ordered arrays of carbon nanotubes (CNTs) are of interest for a broad range of potential applications including energy storage and as catalyst supports. On some substrates such as copper and nickel, CNTs do not grow well or at all. We have previously shown that mesoporous silica thin films can be deposited onto metal substrates including copper and nickel, and that, after removal of the templating surfactant, the mesoporous silica film can be used as template for the electrodeposition of metals to give metal nanostructures.[Campbell et. al., Micro. Meso. Mater., 97, 114-121 (2006)] The size of the metal nanostructures makes them attractive as seeds for growth of CNTs. We have found that under appropriate conditions nickel deposited into mesoporous silica can act as catalyst for CNT growth on a number of different substrates including copper coated silicon wafers, and nickel foam. Using three different furnaces and different feed streams it was found that the growth is sensitive to carbon source; acetylene and ethylene both produced CNTs whereas attempts to produce CNTs using xylene have so far been unsuccessful.Well ordered mesoporous silica thin films could potentially give arrays of nanorod seeds, leading to well ordered arrays of CNTs, SEM images of some of our samples show dense CNT arrays, but do not indicate significant ordering.
A Model Dielectric Function for Graphene from the Infrared to the Ultraviolet
Authors: Boosalis A. , Elmquist R. , Real M. , Nguyen N. , Schubert M. , Hofmann T. 
Published: June 2013

ABSTRACTA modified critical point model dielectric function for graphene is derived here and used to analyze spectroscopic ellipsometry data obtained over a wide spectral range from 3 to 9 eV. Critical point and exciton resonance energies are extracted and discussed. Our findings indicate that epitaxial graphene on SiC to exhibits equivalent exciton behavior to that of suspended graphene. We further apply our model dielectric function to evaluate dielectric function data for highly oriented pyrolytic graphite reported in the literature. Excellent agreement is found between the critical point model developed here and the literature data even for the low energy spectral range up to 1 eV.
Gas-phase Synthesis of Silver Nanoparticles for Plasmonic Biosensors
Authors: Sotiriou Georgios A. , Blattmann Christoph O. , Pratsinis Sotiris E. 
Published: June 2013

ABSTRACTSilver (Ag) nanoparticles dispersed in an amorphous silica (SiO2) matrix or coated by a SiO2 layer were synthesized by flame spray pyrolysis (FSP). The coated nanoparticles were produced by using a modified enclosed FSP setup, in which the SiO2 precursor was injected through a ring above the FSP nozzle at various burner-ring-distances (BRDs), after the core Ag nanoparticles had been formed. The produced nanoparticles were characterized by XRD, BET, TEM and UV/vis analysis. The Ag particle size was possible to be controlled by tuning the FSP parameters. For the SiO2 coated nanoparticles, larger Ag core sizes were obtained for higher BRDs. All the produced nanoparticles exhibited the characteristic plasmon resonance frequency of Ag nanoparticles.
Steady-state and transient electron transport within bulk wurtzite zinc oxide and the resultant electron device performance
Authors: Hadi Walid A. , Shur Michael S. , O’Leary Stephen K. 
Published: June 2013

ABSTRACTWe review some recent results related to the steady-state and transient electron transport that occurs within bulk wurtzite zinc oxide. We employ three-valley Monte Carlo simulations of the electron transport within this material for the purposes of this analysis. Using these results, we devise a means of rendering transparent the electron drift velocity enhancement offered by transient electron transport over steady-state electron transport. A comparison, with results corresponding to gallium nitride, indium nitride, and aluminum nitride, is provided. The device implications of these results are then presented.
3 Dimensional Carbon Nanostructures for Li-ion Battery Anode
Authors: Kang Chiwon , Baskaran Rangasamy , Kim Won-Gi , Sun Yang-Kook , Choi Wonbong 
Published: June 2013

ABSTRACTCarbon nanofibers (CNFs) have been thoroughly investigated as potential anode materials in Li-ion battery owing to their exceptional properties such as the higher surface area to mass ratio, electrical conductivity and mechanical toughness. However, one of the major limitations of nano carbon materials is lower mass loading density. To address this issue, we have developed a novel anode system composed of CNFs directly grown on 3D Cu mesh current collector (hereafter mentioned as 3D CNFs) using a thermal catalytic chemical vapor deposition (CVD) method. Compared to CNF-based anodes on 2D Cu current collector, active The active material loading amount of the 3D CNFs has been found to be 400 % higher while comparing with 2D CNF. Owing to an increase of the active surface area, 3D CNFs demonstrated enhanced electrochemical performance of Li-ion battery in terms of charge capacity (50% improvement), rate capability and cycling life. Interfacial contact between the CNFs and Cu could play a crucial role in promoting the electrochemical properties. The intermediate TiC thin layer, formed at high temperature 750°C, could function as an efficient electric conducting pathway and a strong bonding bridge between the CNFs and Cu. In order to improve the pristine 3D CNF redox reactions, the amorphous Si (a-Si)/3D CNF has been sputter deposited to produce Si wrapped 3D CNF hybrid anode material. It has been found that the electrochemical properties of the a-Si/3D CNF yields superior specific capacity (Cdis 549 mAhg-1, LiC4.1) and cycling stability than that of pristine 3D CNF (461 mAhg-1, LiC4.8).
Thermal Expansion-Recovery Microscopy (ThERM) for microstructural characterization
Authors: Domené Esteban A. , Mingolo Nélida , Martínez Oscar E. 
Published: June 2013

ABSTRACTIn this work we compare two different detection schemes that are sensitive to the focus shift of a probe beam due to induced surface curvature. The technique on which both detection schemes are based is called ThERM (Thermal Expansion-Recovery Microscopy) and allows the retrieval of the thermal diffusivity at microscopic levels, hence mapping such magnitude over a sample surface. The induced thermal expansion defocuses the probe beam due to the surface deformation (curvature). The dependence of the defocusing with the pump modulation frequency yields the thermal diffusivity of the sample at the impinging location. The explored depth is controlled by the pump beam size. By scanning both beams, a complete map of the thermal diffusivity can be retrieved.
Improved Yellow Light Emission in the Achievement of Dichromatic White Light Emitting Diodes
Authors: Si Zhao , Wei Tongbo , Ma Jun , Zhang Ning , Liu Zhe , Wei Xuecheng , Wang Xiaodong , Lu Hongxi , Wang Junxi , Li Jinmin 
Published: June 2013

ABSTRACTA study about the achievement of dichromatic white light-emitting diodes (LEDs) was performed. A series of dual wavelength LEDs with different last quantum-well (LQW) structure were fabricated. The bottom seven blue light QWs (close to n-GaN layer) of the four samples were the same. The LQW of sample A was 3 nm, and that of sample B, C and D were 6 nm, a special high In content ultra-thin layer was inserted in the middle of the LQW of sample C and on top of that of sample D. XRD results showed In concentration fluctuation and good interface quality of the four samples. PL measurements showed dual wavelength emitting, the blue light peak position of the four samples were almost the same, sample A with a narrower LQW showed an emission wavelength much shorter than that of sample B, C, D. EL measurement was done at an injection current of 100 mA. Sample A only showed LQW emission due to holes distribution. Because of wider LQW, the emission wavelength of sample B, C and D was longer and peak intensity was weaker. Sample D with insert layer on top of LQW showed strongest yellow light emission with a blue peak. As the injection current increased, sample A showed highest output light power due to narrower LQW. Of the other three samples with wider LQW, sample D showed highest output power. Effective yellow light emission has always been an obstacle to the achievement of dichromatic white LED. Sample D with insert layer close to p-GaN can confine the hole distribution more effectively hence the recombination of holes and electrons was enhanced, the yellow light emission was improved and dichromatic white LED was achieved.
A Novel Technique for Growth of Lithium-free ZnO Single Crystals
Authors: Wang Shaoping , Kopec Aneta , Timmerman Andrew G. 
Published: June 2013

ABSTRACTA ZnO single crystal is a native substrate for epitaxial growth of high-quality thin films of ZnO-based Group II-oxides (e.g. ZnO, ZnMgO, ZnCdO) for variety of devices, such as UV and visible-light emitting diodes (LEDs), UV laser diodes and solar-blind UV detectors. Currently, commercially available ZnO single crystal wafers are produced using a hydrothermal technique. The main drawback of hydrothermal growth technique is that the ZnO crystals contain large amounts of alkaline metals, such as Li and K. These alkaline metals are electrically active and hence can be detrimental to device performances. In this paper, results from a recently developed novel growth technique for ZnO single crystal boules are presented. Lithium-free ZnO single crystal boules of up to 1 inch in diameter was demonstrated using the novel technique. Results from crystal growth and materials characterization will be discussed.
Government Public Housing Health Needs Assessment: Focus on Race, Ethnicity, and the Older Adult: Background, Methods, and Demographics
Authors: Lascher Steven , Tasir-Rodriguez Wesley , Moon Grace , Irizzary Maria , Baney Matthew , Kellogg F. Russell 
Published: June 2013

St. Vincent’s Catholic Medical Centers of New York initiated a study in 2009 to assess the health needs of residents of New York City (NYC) municipal housing at the Robert Fulton public housing complex in Manhattan. The aim of this project was to provide valid data on perceived health services needs of the residents of a NYC housing project. These data may also be used to support hospital and community collaborative strategic decisions for developing resident-appropriate health and social services and would be valuable for use in formulating policies and programs by other interested nonprofit health and social services organizations and government. We designed a 28-item instrument and pilot tested it with our research team and members of the population under study.The English and Spanish surveys were designed as an inperson surveyor-administered instruments addressing four domains: demographics, access and barriers to health care services, risk behaviors, and perceived health needs. The sampling was an apartment-level stratified random sampling. A 20%, 188 apartment sample was drawn from the population of 944 housing units. Our response rate was 92% (173/188 apartments).Background, methods, and demographic results are reported in this article. A second article will report on the needs assessment results.