bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thromboprophylaxis in a Pediatric Hospital: A Patient-Safety and Quality-Improvement Initiative
Authors: Raffini Leslie , Trimarchi Tara , Beliveau Johanna , Davis Daniela 
Published: April 2011

OBJECTIVES:
Venous thromboembolism (VTE) prophylaxis for patients at risk is often overlooked in pediatric health care institutions, which provides an opportunity to improve patient care. The objectives of this study were to review our current hospital practice, identify a population at high risk, and formulate institutional guidelines for thromboprophylaxis.

METHODS:
This was a prospective patient-safety and quality-improvement project performed at a large pediatric tertiary care hospital. We developed criteria for assessing risk and selecting prophylactic intervention through analysis of the age distribution and underlying medical conditions of patients with VTE at our center, literature review of adult recommendations for thromboprophylaxis, and consensus opinion of multiple specialists at our institution. A patient-care policy was developed to assess VTE risk and prescribe the appropriate thromboprophylaxis regimen. The primary outcome measure was compliance with thromboprophylaxis guidelines in patients at risk for VTE.

RESULTS:
Over the 4-year study period, the observed rate of VTE prophylaxis in patients at risk increased from a baseline of 22% to an average rate of 82%, and there were intermittent improvements up to 100%.

CONCLUSIONS:
Although some of the details may vary from center to center, many of the discussed principles and practices involved in instituting a VTE-prevention program are applicable to other pediatric institutions. Despite the fact that the risk of VTE in hospitalized children is much lower than that in adults, there are patients in pediatric hospitals who deserve systematic screening and thoughtful application of preventative measures.
A Systematic Review of Medical Treatments for Children With Autism Spectrum Disorders
Authors: McPheeters Melissa L. , Warren Zachary , Sathe Nila , Bruzek Jennifer L. , Krishnaswami Shanthi , Jerome Rebecca N. , Veenstra-VanderWeele Jeremy 
Published: April 2011

CONTEXT:As many as 1 in every 110 children in the United States has an autism spectrum disorder (ASD). Many medical treatments for ASDs have been proposed and studied, but there is currently no consensus regarding which interventions are most effective.OBJECTIVE:To systematically review evidence regarding medical treatments for children aged 12 years and younger with ASDs.METHODS:We searched the Medline, PsycInfo, and ERIC (Education Resources Information Center) databases from 2000 to May 2010, regulatory data for approved medications, and reference lists of included articles. Two reviewers independently assessed each study against predetermined inclusion/exclusion criteria. Studies of secretin were not included in this review. Two reviewers independently extracted data regarding participant and intervention characteristics, assessment techniques, and outcomes and assigned overall quality and strength-of-evidence ratings on the basis of predetermined criteria.RESULTS:Evidence supports the benefit of risperidone and aripiprazole for challenging and repetitive behaviors in children with ASDs. Evidence also supports significant adverse effects of these medications. Insufficient strength of evidence is present to evaluate the benefits or adverse effects for any other medical treatments for ASDs, including serotonin-reuptake inhibitors and stimulant medications.CONCLUSIONS:Although many children with ASDs are currently treated with medical interventions, strikingly little evidence exists to support benefit for most treatments. Risperidone and aripiprazole have shown benefit for challenging and repetitive behaviors, but associated adverse effects limit their use to patients with severe impairment or risk of injury.
Two-step Sintering Process for Lutetium Oxide Transparent Ceramics
Authors: Guo Xiaomei , Li Kewen K. , Wang Yanyun , Zou Yingyin K. , Jiang Hua 
Published: April 2011

ABSTRACTDuring a two-step sintering practice, important factors such as final grain sizes and residual pore status can be controlled through adjusting the first and second step sintering temperatures and durations. Moreover, the sintering temperatures (both the first and the second step) can be several hundred degrees lower than those in a traditional sintering process to obtain fully dense ceramics. Therefore, it is a potentially cost-effective preparation procedure for ceramics with fine grains. In this work, we successfully demonstrated the synthesis of aggregate-free sesquioxide nanometer-sized powders with a narrow size distribution through a modified chemical co-precipitation process. Subsequently, ytterbium-doped Lu2O3 ceramics of near full density were obtained through a two-step sintering process.
Facile synthesis of polypyrrole/graphene nanosheet-based nanocomposites as catalyst support for fuel cells
Authors: Saner Burcu , Gürsel Selmiye Alkan , Yürüm Yuda 
Published: April 2011

ABSTRACTThe integration of catalyst metals into the graphene-based composites can be a new way to ensure thermal and electronic conductivities of the catalyst support materials in polymer electrolyte membrane fuel cells. In this work, graphene nanosheets were synthesized via a mild and safer chemical route including three major steps: graphite oxidation, ultrasonic treatment and chemical reduction. Then, polypyrrole was coated on graphene nanosheets by in-situ polymerization to fabricate polypyrrole/graphene nanosheet-based nanocomposites as the catalyst supports. Pt nanoparticles were uniformly dispersed on the surface of nanocomposites by sonication technique.
Process Optimization for Nanocrystalline Cellulose Production from Microcrystalline Cellulose
Authors: Danumah Christophe , Fenniri Hicham 
Published: April 2011

ABSTRACTA process optimization has been developed for obtaining nanocrystalline cellulose (NCC) by acid hydrolysis of commercially available microcrystalline cellulose (MCC) in high yield (~ 40-50%). This method was based on control of key parameters such as the rate of addition of sulfuric acid solution to the MCC/water suspension, the mixing speed, the volume of collected NCC suspensions and the volume ratio of NCC suspension to water during dialysis. The resulting NCC products were characterized by x-ray diffraction (XRD), thermogravimetric analysis (TGA), elemental analysis (EA), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Electron microscopy results showed that the rod-shaped NCC had lengths and widths of about 40-400 nm and 5-40 nm, respectively.
Graphitic Carbon Nanoparticles from Asphaltenes
Authors: Danumah Christophe , Myles Andrew J. , Fenniri Hicham 
Published: April 2011

ABSTRACTWe report preliminary studies on the preparation of carbon nanoparticles (CNPs) of ~ 20 nm in diameter derived from asphaltenes under mild conditions. This transformation occurred upon heating a thin film of asphaltenes cast on a carbon coated copper grid under both nitrogen and oxygen atmosphere. The resulting CNPs were characterized by thermogravimetric analysis (TGA), scanning/transmission electron microscopy (SEM/STEM), transmission electron microscopy (TEM), elemental analysis (EA) and Auger electron spectroscopy (AES). The findings point towards asphaltenes, a crude oil by-product, as a potential source for carbon nanomaterials.
Scanning Thermal Lithography as a Tool for Highly Localized Nanoscale Chemical Surface Functionalization
Authors: Duvigneau Joost , Schönherr Holger , Vancso G. Julius 
Published: April 2011

ABSTRACTWe report on Scanning Thermal Lithography (SThL), a recently introduced lithographic tool, for local thermochemistry on tert-butyl acrylate based polymer films featuring chemical cross links. The tailored polymer films afford platforms for controlled high molecular density coupling and surface immobilization of biologically relevant molecules, such as proteins. The thermally labile tert-butyl ester groups in tert-butyl acrylate based polymer films can be cleaved in air at temperatures above 150 °C to yield carboxylic acid functional groups for further (bio)- conjugation. The films were optimized to avoid plastic deformation at the elevated temperatures used during SThL. Exploiting these properties patterns with length scales as small as 35 ± 6 nm have been successfully thermally activated with SThL. Hence SThL comprises an attractive approach for the development of e.g. (bio)sensors and platforms for cell surface interaction studies with nanoscale patterns.
Study of Selectively Permeable Coatings to Textiles
Authors: Sargent Joseph G. , Lee Jun S. , Reynaud Emmanuelle , Gilbert Michael D. , Sloan James M. 
Published: April 2011

ABSTRACTBreathable barrier textiles for both chemical agent and moisture are being actively developed for military and industrial applications. An ideal approach is to coat textiles with a semi-permeable film that allows the transport of water while still serving as a barrier for chemical agents. Sulfonated poly (styrene-block-isobutylene-block-styrene) (SIBS) copolymer spontaneously phase separates upon drying from solution to produce a nanostructured film with the controlled barrier functionality for water permeation and repelling of chemical agents.The objective of this research is to investigate coating uniformity and phase morphology of SIBS coating materials fabricated by novel solvent combinations. Scanning electron microscopy analysis is used for the assessment of the coating uniformity as well as the level of adhesion between the polymer coating and fabric substrate. Transmission electron microscopy is used to characterize the phase separation morphology of the SIBS copolymer coating. The mechanical behavior of the coated fabric is determined through tensile and shear tests and is compared to the bare fabric behavior. The goal of this study is to relate the processing conditions of the final nanostructured block copolymer coated fabric produced on industrial scale.
Assembly of Nanoparticles from Bioactive Peptides and Chitosan
Authors: Hu B. , Huang Q. R. , Zeng X. X. 
Published: April 2011

ABSTRACTAssembly of nanoparticles from bioactive peptides, caseinophosphopeptides (CPPs) and chitosan (CS) at physiological conditions and various CS/CPPs mass ratios have been systematically studied using a combination of turbidimetric titration, dynamic light scattering (DLS), electrophoretic mobility (zeta-potential) and transmission electron microscopy (TEM). Peptides, incorporated with CS forming nanoparticles, have already been prepared and identified using liquid chromatography-tandem mass spectrometry (LC-MS-MS). They are characteristic with different amount of clusters of phosphorylated seryl residues. At low salt concentration, an increase of CS/CPP mass ratio shifted the critical pHϕ1, which designated the formation of CS/CPP nanocomplexes, as well as pHmax, representing the neutralization of positive and negative charge to higher pH values. The peptide-polymer binding mechanism was analyzed according to the results of DLS, electrophoretic mobility, and TEM. First, negatively charged CPPs absorbed to positively charged CS molecular chain to form intrapolymer nanocomplexes saturated with CPPs (CPPNP). Then, the negatively charged CPPNP was bridged by added positively charged CS. Finally, novel nano-scaled spherical brushes were formed as additional CS molecule absorbed back to and bound the CPPNP. Phosphorylated groups in the CPPs might be the dominant sites for interaction with –NH3+ on the CS molecular chain.
High Gain, Silicon-on-insulator Photodetector with Multiple Gates and a Nanowire Based Narrow-wide-narrow Channel
Authors: Roudsari Anita Fadavi , Saini Simarjeet S. , O Nixon , Anantram M. P. 
Published: April 2011

ABSTRACTWe propose a phototransistor geometry that incorporates silicon nanowires (SiNW) in the device channel. A set of two gates controls the charge flow inside the NW. This improves the device photo-response more than 10x when compared with a single gate phototransistor, leading to a photo-responsivity of greater than 104(A/W), while the dark properties of both devices are similar.
A Novel High-Dynamic a-Si:H Multicolor pin-Detector with ZnO:Al Front and Back Contacts
Authors: Bablich Andreas , Watty Krystian , Merfort Christian , Seibel Konstantin , Boehm Markus 
Published: April 2011

ABSTRACTConventional silicon sensors provide insufficient capability for color reproduction by producing three color signals (RGB) to fit their pixel sensitivities to that of the human eye. Photo detector devices based on a-SiC:H and a-SiGe:H offer the opportunity to shift spectral sensitivity continuously by varying external bias voltages. Based on the measurement results of Rieve et al. [2] we determined the absorption coefficients of a group of a-SiC:H and a-SiGe:H layers to simulate the penetration depth of photons at different energies into the device structure [3]. Knowing the indices of absorption, refraction and extinction, it is possible to engineer diodes in such a way that accumulations of charge carriers are generated at varying device depths. The use of common chromium (Cr) cathodes avoids a sharp falling edge of the sensitivity towards longer wavelengths. The use of low reflective and highly conductive aluminum-doped zinc oxide (ZnO:Al) as a material for the back contact of the diodes suppresses Fresnel reflections and has been verified experimentally. A dynamic range of more than 100 dB at 1000 lux could be obtained by I-/V- measurements of a-Si:H pin diodes fabricated between two ZnO:Al contacts. Optically the detectors show maxima between 440 nm and 630 nm with reduced Fresnel reflections and a very low leakage current of 10-8A/cm2 at -5 V bias voltage. Present research efforts concentrate on the verification of the optical properties and exact thicknesses of the chosen layers as well as on the development of a front and back illumination device structure which ensures a continuous spectral shift of the photosensitivity. This work requires extensive bandgap engineering and offers good prospects to improve security imaging tools as well as chemical analysis systems.
A Chemical Gas Sensor from Large-Scale Thermal CVD Derived Graphene
Authors: Song Xiaojuan , Wagner Brent , Kang Zhitao 
Published: April 2011

ABSTRACTLarge-scale graphene sheets were grown on thin nickel film coated Si substrates using a reliable and repeatable thermal Chemical Vapor Deposition (CVD) technique. The graphene films were then transferred onto a SiO2 coated Si wafer to fabricate a 5 mm x 5 mm resistive sensor structure. Raman spectroscopy analysis confirmed the existence of graphene. Preliminary sensing results were demonstrated by the detection of hazardous gases such as NO2 and MMH (mono-methyl hydrazine). Characterization of the device channel resistivity (switching response) was conducted as a function of the analyte type and concentration. The sensor response indicates a charge transfer mechanism between the analytes and graphene.
Evaluation of Graphene and Graphene Derivatives for RF-Impedance Based Sensing
Authors: Xing Yun , Huang Hong , Zhuang Yan 
Published: April 2011

ABSTRACTGraphene and its derivatives have attracted much attention for potential applications in biological sensing systems because of their unique 2D structural, surface and electronic properties. Reports on graphene - based electrochemical impedance biosensors are emerging rapidly. In this research, we have explored the RF (radio frequency) impedance –based sensing feasibility of graphene and graphene derivative materials on the coplanar waveguide (CPW) device. The transmission line based sensing experiments demonstrated clear and significant blueshifts of resonance frequencies and decrease of the resistance at and beyond resonance frequencies after graphene oxide is absorbed with DNA. The results may lead to an alternative approach in developing graphene based chemical and biosensors.
Ceramic Thin Films for High Integration Density Capacitor Applications
Authors: Taroata Dan , Cheema Tarik A. , Fischer Wolf-Joachim , Garnweitner Georg , Schmid Guenter 
Published: April 2011

ABSTRACTWe report a novel concept for the direct integration of capacitors in printed circuit boards using ultra-small BaTiO3 and ZrO2 nanoparticles prepared by a chemical method. Electrical properties comparable to surface mount ceramic capacitors were achieved by proper processing of the nanoparticles, achieving a device-yield of >90% under research environment. The loss factor of the presented integrated capacitors does not exceed 0.05 independent of frequency, capacitor’s electrode area or applied bias voltage.
Quantum rods and dots-based structures & devices: Low cost aqueous synthesis and bandgap engineering for solar hydrogen and solar cells applications
Authors: Vayssieres Lionel 
Published: April 2011

ABSTRACTIf one considers the largest and geographically balanced free natural resource available on Earth, that is seawater, and that more sunlight energy is striking our blue planet in one hour than all of our annual energy consumption, the direct solar-to-hydrogen conversion by photo-oxidation of seawater is a very straightforward and attractive solution for the production of hydrogen, as it is clean, sustainable and renewable. It offers an alternative solution to fossil-fuel-based energy sources and explains the tremendous interest in renewable, sustainable energy sources and materials for energy conversion. However, the materials requirements for water splitting and thus the direct solar-to-hydrogen generation are drastic. The materials must be stable in water, which rules out many classes of materials. They must also be stable under illumination against photocorrosion and their bandgap must be small enough to absorb visible light, but large enough not to “dissolve” once illuminated. Finally, their band edges must be positioned below and above the redox potential of hydrogen and oxygen, respectively. Bandgap energy and band-edge positions, as well as the overall band structure of semiconductors are of crucial importance in photoelectrochemical and photocatalytic applications. The energy position of the band edges can be controlled by the electronegativity of the dopants and solution pH, as well as by new concepts such as quantum confinement effects and the fabrication of novel hetero-nanostructures. Fulfilling those requirements while keeping the cost of the materials low is a tremendously difficult challenge, which explains why solar hydrogen generation is still in its infancy. Novel approach and latest development combining low cost aqueous synthesis techniques, vertically oriented metal oxide nanorods and quantum confinement effects probed by x-ray spectroscopies from synchrotron radiation is presented leading to stable and cost-effective visible-light-active semiconductors for seawater splitting, the holy grail of photocatalysis.
Preparation and Characterization of Nanostructured Silicon for Optoelectronic Applications
Authors: Ryu Y. S. , Filios A. , Paek Y. , Ryu S. 
Published: April 2011

ABSTRACTSilicon is by far the most successful material in the microelectronics industry enjoying a well-established fabrication and processing infrastructure. Two of the main challenges in traditional silicon electronic devices are (a) silicon’s relatively small and indirect fundamental energy band-gap, which severely limits optoelectronic applications, and (b) the absence of a suitable material to form a heterojunction barrier on silicon. Silicon based nanostructures are being explored as potential candidates to extent the applications of silicon in optoelectronics, provide for high-speed silicon quantum devices, increase the efficiency and reduce the cost in silicon photovoltaic solar cells, and facilitate cost-effective silicon sensors for biological, environmental, and other applications. Quantum size silicon nanolayers, nanowires, and nanodots embedded in oxide, nitride, and other amorphous matrices may provide an effective barrier for silicon, as well as band-gap engineering and enhanced optical transitions for solar cell and optoelectronic applications.
What is the true nature of conducting proton in perovskite ceramic membrane: hydroxyl ion or interstitial proton ?
Authors: Slodczyk Aneta , Colomban Philippe , Zaafrani Oumaya , Lacroix Olivier , Loricourt Johan , Grasset Frederic , Sala Beatrice 
Published: April 2011

ABSTRACTThe proton conducting perovskites are widely investigated due to their high potential as electrolyte membranes of fuel cells, water steam electrolysers and CO2/syngas converters. Our comprehensive spectroscopic (Raman, IR, neutron), thermogravimetric, elastic and quasi-elastic neutron diffusion as well as conductivity studies performed on Ln/RE- modified zirconate ceramics with controlled densification (90-99% of theoretical density) reveal the important differences between the surface and bulk protonic species. The results clearly show that trivialization of the protonation process complexity can favorite the adsorption of the surface protonic species (hydroxide, hydrocarbonates, etc), prohibit the incorporation of bulk protons, i.e. species responsible for the proton conduction and confuse the understanding of fundamental aspects concerning the proton conductors such as the true nature of conducting species. Our studies reveal that OH- ions are located at the surface of poor densified ceramic and the bulk conducting protons exhibit an ionic, free of covalent-bonded nature.
Raman spectrum of group IV nanowires: influence of temperature
Authors: Anaya J. , Prieto C. , Souto J. , Jiménez J. , Rodríguez A. , Sangrador J. , Rodríguez T. 
Published: April 2011

ABSTRACTGroup IV semiconductor nanowires are characterized by Raman spectroscopy. The results are analyzed in terms of the heating induced by the laser beam on the nanowires. By solving the heat transport equation one can simulate the temperature reached by the NWs under the exposure to a laser beam. The results are illustrated with Si and Si1-xGex nanowires. Both bundles of nanowires and individual nanowires are studied. The main experimental conditions contributing to the nanowire heating are discussed.
Catalytic activity of nanostructured plate-type Cu-based on ZnO nanorods promoted by additive metals for oxidative steam reforming of methanol
Authors: Li Chien-Cheng , Lin Ran-Jin , Lin Hong-Ping , Chen Li-Chyong , Chen Kuei-Hsien 
Published: April 2011

ABSTRACTThe Cu-based film catalysts with various additive metals have been successfully prepared by the electroless plating on ZnO nanorods/stainless steel substrates. The microstructure features of the Cu-based films are highly porous and composed of plate-type grains. The addition of zirconium, aluminum, and iron into Cu-based film catalyst can improve the activity and the stability of the film catalysts. The catalytic durability of the Cu-based film catalysts has also been improved by addition of Zr, Al, and Fe into Cu-based films. This is attributed to the formation of the stable ZrO2, Al2O3, and Fe2O3 nanoparticles with good dispersion in the films.
Group IV Nanocrystals for Silicon Photovoltaics
Authors: Liu X. , Saini S. , Vanhoutte M. , Bakalis J. , Yau W. , Eshed A. , Kimerling L.C. , Pervez N. , Kymissis I. , Wong C.W. 
Published: April 2011

ABSTRACTSilicon nanocrystals (nc-Si), have been shown to act as opto-electronic centers enabling light emission by carrier recombination, when precipitated in a silicon nitride (Si3N4) host. In this work, nc-Si and Germanium nanocrystals (nc-Ge) are studied in sputtered films of Si3N4 and SiGeN for application as tandem cell layers in a Si solar cell. The samples are annealed in a nitrogen gas and forming gas ambient, from 500 ºC to 900 ºC, to investigate the influence of temperature on photoluminescence and photoconductivity.