bluuebunny/crossref_metadata_2025_split huggingface dataset:
High- v. low-dose quetiapine in schizophrenia: meta-analysis
Authors: Painuly Nitesh 
Published: January 2010

Aims and methodTo study the difference between high- and low-dose quetiapine in acute treatment of schizophrenia. Data available from published double-blind fixed-dose trials were combined and analysed.ResultsThere was no statistically significant difference between high- (750–800 mg/day) and low-dose (300–400 mg/day) quetiapine in terms of the response rate, change in positive symptoms score and the discontinuation rates either as a result of lack of response or adverse effects.Clinical implicationsCombined evidence from fixed-dose trials does not support the prevalent practice of targeting the higher dose of quetiapine for optimal treatment response in schizophrenia.
Failure Analysis Using Optical Evaluation Technique (OBIC) of LDs for Fiber Optical Communication
Authors: Takeshita Tatsuya , Oohashi Hiromi 
Published: January 2010

AbstractThe introduction of high-speed services for fiber-optic access subscribers has led to a huge growth in data traffic. The rapid diversification of services means that next generation networks must be built quickly, economically and reliably.A high temperature laser allows us to eliminate the thermo-electric cooler conventionally needed in a transmitter module, which results in reductions in cost, power consumption and size. Moreover, a high-power laser provides a wide tolerance when coupling optical fibers. In addition, a high-power pump laser is needed to realize a wide-band and high-power erbium-doped fiber amplifier. This makes high-performance laser chips one of the keys to achieving highly reliable and cost-effective systems.In terms of laser reliability, we must clarify the degradation mechanism and postpone or suppress degradation if we are to achieve a reliable high-performance laser. We have analyzed degraded lasers using the optical beam induced current (OBIC) technique. When there are nonradiative recombination centers in the degraded region, the OBIC intensity decreases with increases in recombination density. This technique has the advantages of being non-destructive and highly sensitive. In addition, it provides high space resolution in degradation analyses.The OBIC is measured through the window of a transistor outline (TO) can before and after aging. Then, by using the same LDs we can detect an OBIC change for several aging times. We can both detect the degraded region and layer, and estimate the degree of laser degradation by employing the relative OBIC intensity prior to aging. This OBIC technique is useful for analyzing the degree of laser degradation.Moreover, the incident wavelength can be changed by changing the optical source in the OBIC measurement setup, which in turn changes the absorption layer and the penetration distance. Some degraded laser layers are reveled by using these several wavelengths absorbed in different layers. In addition, degradation in the waveguide interior is detected by using an incident wavelength with long penetration. Thus, by monitoring the OBIC intensity at several wavelengths as well as before and after aging, we are able to discuss sudden and wear-out laser failures. In our presentation, we will introduce examples using the OBIC technique that contributed to the improvement of laser reliability.
Observation of Dopant Profile of Transistors Using Scanning Nonlinear Dielectric Microscopy
Authors: Honda Koichiro , Cho Yasuo 
Published: January 2010

AbstractWe have demonstrated that scanning nonlinear dielectric microscopy (SNDM) exhibited high performance and high resolution in observing the dopant concentration profile of transistors. In this study, good quantitative agreement between the SNDM signals and dopant density values obtained by SIMS in standard Si samples, which dopant concentrations have been calibrated. We succeeded in visualizing high-resolution dopant profiles in n- and p-type MOSFET with 40 nm gate channels. It is considered that SNDM would be an effective method in measuring the quantitative two-dimensional dopant profiles of transistors. Finally, we have succeeded in detecting the dopant profiles of SRAM memory cell transistors.
Electrical and Optical Properties of CVT-grown ZnO Crystals
Authors: Abe Koji , Oiwa Masanori 
Published: January 2010

AbstractEffects of H2O partial pressure on ZnO crystal growth by chemical vapor transport (CVT) have been investigated. The use of H2O causes the increase in growth rate of ZnO, indicating that H2O acts as a dominant oxygen source in ZnO growth by CVT. The use of H2O also improves structural, electrical, and optical properties of the CVT-grown ZnO crystals. A sharp X-ray rocking curve for the ZnO (0002) reflection was obtained, and the full width at half maximum value was 38 arcsec. Strong near band edge emission was observed in photoluminescence spectra at room temperature. Both carrier concentration and Hall mobility increased with partial pressure of H2O. The dependence of the carrier concentration on temperature indicates that there exist two donors in the CVT-grown ZnO crystals. The estimated ionization energy for the shallow donor was 35±5 meV and that for the deep donor was 115±5 meV.
Traps and Defects in AlGaN-GaN High Electron Mobility Transistors on Semi-Insulating SiC Substrates
Authors: Sin Yongkun , Deionno Erica , Foran Brendan , Presser Nathan 
Published: January 2010

AbstractHigh electron mobility transistors (HEMTs) based on AlGaN-GaN hetero-structures are promising for high power, high speed, and high temperature operation. Especially, AlGaN-GaN HEMTs grown on semi-insulating (SI) SiC substrates are the most promising for both military and commercial applications. High performance characteristics from these devices are possible in part due to the presence of high two-dimensional electron gas charge sheet density maintaining a high Hall mobility at the AlGaN barrier-GaN buffer hetero-interface and in part due to high thermal conductivity of the SiC substrates. However, long-term reliability of these devices still remains a major concern because of the large number of traps and defects present both in the bulk as well as at the surface leading to undesirable characteristics including current collapse. We report on the study of traps and defects in two MOCVD-grown structures: Al0.27Ga0.73N HEMTs on SI SiC substrates and Al0.27Ga0.73N Schottky diodes on conducting SiC substrates. Our HEMT structures consisting of undoped AlGaN barrier and GaN buffer layers grown on an AlN nucleation layer show a charge sheet density of ∼1013/cm2 and a Hall mobility of ∼1500cm2/V·sec. Deep level transient spectroscopy (DLTS) was employed to study traps in AlGaN Schottky diodes and HEMTs fabricated with different Schottky contacts consisting of Pt/Au and Ni/Au. Focused ion beam was employed to prepare both cross-sectional and plan view TEM samples for defect analysis using a high resolution TEM.
Size Reduction and Rare Earth Doping of GaN Powders through Ball Milling
Authors: Guo Xiaomei , Thomas Tiju , Li Kewen Kevin , Qi Jifa , Wang Yangyun , Chen Xuesheng , Zhang Jingwen , Spencer Michael G. , Zhao Hua , Zou Yingyin Kevin , Jiang Hua , Di Bartolo Baldassare 
Published: January 2010

AbstractBall milling of ammonothermally synthesized GaN powders was performed in an ethanol solution for a variety of durations, resulting in average particle sizes of nanometer. The ball milled powders showed an obviously brightened color and improved dispersability, indicating reduced levels of aggregation. X-ray diffraction (XRD) peaks of the ball milled GaN powders were significantly broadened compared to those of the as-synthesized powders. The broadening of the XRD peaks was partially attributed to the reduction in the average particle size, which was confirmed through SEM analyses. On the other hand, rare earth doping of commercial GaN powders was also achieved through a ball mill assisted solid state reaction process. Rare earth salts were mixed with GaN powder by ball milling. The as-milled powders were heat treated under different conditions to facilitate the dopant diffusion. Luminescence properties of the rare earth doped GaN powders at near infrared range were investigated and the results were discussed.
Short period p-type AlN/AlGaN superlattices for deep UV light emitters
Authors: Nikishin Sergey A. , Borisov Boris , Mansurov Vladimir , Pandikunta Mahesh , Chary Indra , Rajanna Gautam , Bernussi Ayrton , Kudriavtsev Yuriy , Asomoza Rene , Bulashevich Kirill , Karpov Sergey Yu. , Sohal Sandeep , Holtz Mark 
Published: January 2010

AbstractThe Mg doped AlN/AlxGa1-xN (0.03 ≤ x ≤ 0.05) short period superlattices (SPSLs) were grown by gas source molecular beam epitaxy on (0001) sapphire substrates. The average AlN mole fraction is ∼ 0.7 and the hole concentration is ∼ 7×1017 cm-3. Contacts formed to the SPSLs using Ni/Au bilayer are found to have specific contact resistance ∼ 5×10-5 Ωcm2 near room temperature and to show weak temperature dependence attributed to activation of Mg acceptors in the AlN barriers of SPSLs. These p-SPSLs are attractive for fabrication of transparent low resistive ohmic contacts for deep UV LEDs.
THz Emission from InN
Authors: Ahn Hyeyoung , Yeh Yi-Jou , Hong Yu-Liang , Gwo Shangjr 
Published: January 2010

AbstractWe report the terahertz (THz) emission from the wurzite indium nitride (InN) films grown by molecular beam epitaxy (MBE). More than two orders of magnitude of THz power enhancement has been achieved from the InN film grown along the a-axis and magnesium (Mg) doped InN with a critical carrier concentration. The primary radiation mechanism of the a-plane InN film is found to be due to the acceleration of photoexcited carriers under the polarization-induced in-plane electric field perpendicular to the a-axis. Apparent azimuthal angle dependences of THz wave amplitude and the second harmonic generation are observed from a-plane InN. In the Mg-doped films, Mg as the acceptors compensate the native donors in the InN films and large band bending over a wider space-charge region causes the enhancement of THz emission power compared to the undoped InN.
Molecular dynamics of carbon nanobearings
Authors: Shintani K. , Arai N. , Shintani K. 
Published: January 2010

AbstractA concept of nanoscale bearing structures utilizing nanocarbon materials is presented based on the prediction via molecular dynamics simulations. The proposed mechanism consists of a graphene layer, intercalated single walled carbon nanotubes (SWNTs), and substrate graphenes. It is found that the friction against the movement of the uppermost graphene is smallest for the 1 SWNT model.
Suppression of Inelastic Deformation in Multilayer Microcantilevers with Nanoscale Coating
Authors: Lin I-Kuan , Zhang Xin , Zhang Yanhang 
Published: January 2010

AbstractMultilayer microcantilevers present in micro-/nano- electromechanical system (MEMS/NEMS) applications serving passive and active structural roles. The application and commercialization of MEMS devices suffer from reliability problems. Appropriate nanocoatings, such as atomic layer deposition (ALD), have been demonstrated to be promising solutions for these reliability problems in MEMS devices. However, the micro/nano- mechanics within and/or between the microcantilevers and nanocoatings are not fully understood, especially when temperature, time, microstructural evolution and material nonlinearities play significant roles in thermomechanical response. The overall goal of this work is to suppress and understand the inelastic deformation and microstructural evolution in multilayer microcantilevers with nanocoatings. Moreover, to better understand the stress relief and Al2O3 suppression mechanism, scanning electron microscopy (SEM) was employed to explore the microstructural evolution.
The Tunability in Mechanical Properties and Fracture Toughness of Sputtered Silicon Oxynitride Thin Films for MEMS-based Infrared Detectors
Authors: Lin I-Kuan , Wu Ping-Hsin , Ou Kuang-Shun , Chen Kuo-Shen , Zhang Xin 
Published: January 2010

AbstractThis paper presents the mechanical characterization of the elastic modulus, hardness and fracture toughness of silicon oxynitride films (SiON) with different oxygen and nitrogen content, subjected to thermal annealing processed at 400 °C and 800 °C. The Fourier-transform infrared (FT-IR) spectroscopy was employed to characterize the SiON films with respect to the absorbance peak in the infrared spectrum. The nanoindentation testing showed that both the elastic modulus and hardness slightly increased after thermal annealing. Finally, the fracture toughness of the SiON films were estimated using Vickers micro-indentation tests and the result revealed that the fracture toughness decreased with increasing rapid thermal annealing (RTA) temperature and nitrogen content. We believe these results benefit microelectromechanical systems (MEMS) in regards to maintaining the structural integrity and improving reliability performance.
Advanced Wet Etch Bulk Micromachining in {100} Silicon Wafers
Authors: Pal Prem , Sato Kazuo 
Published: January 2010

AbstractIn this work we have developed novel microfabrication processes using wet anisotropic etchants to perform advanced bulk micromachining in {100}Si wafers for the realization of microelectromechanical systems (MEMS) structures with new shapes. The etching is performed in two steps in pure and Triton-X-100 [C14H22O(C2H4O)n, n = 9-10] added 25 wt% tetramethyl ammonium hydroxide (TMAH) solutions. The local oxidation of silicon (LOCOS) is attempted after the first anisotropic etching step in order to protect the exposed silicon. Two types of structures (fixed and freestanding) are fabricated. The fixed structures contain perfectly sharp corners and edges. Thermally grown silicon dioxide (SiO2) is used for the fabrication of freestanding structures. Present research is an approach to fabricate advanced MEMS structures, extending the range of 3D structures fabricated by silicon wet anisotropic etching.
A Simple Technique for Sub-10 nm Planar Nanofluidic Channel Fabrication
Authors: Song Chunrong , Wang Pingshan 
Published: January 2010

AbstractA simple and low-cost technique is demonstrated to fabricate sub-10 nm planar nanofluidic channels. Native oxide on silicon surface is etched with a multiple hydrofluoric (HF)-etch / SiO2-regrowth process. Shallow Si trenches with 3 nm to 24 nm depths are obtained at an etch rate of 1 nm per HF dip. The trenches are uniform with a surface r.m.s. roughness of 0.4 - 0.6 nm. A low-temperature and low-voltage anodic wafer bonding process is then used to form planar nanofluidic channels. Minimum aspect ratio (depth/width) of the fabricated sub-10 nm nanochannels is around 0.001-0.002.
A Low-Range Drift-Free Bio-compatible Pressure Sensor Based on P(VDF-TrFE) Piezoelectric Thin Film
Authors: Li Xiaoyang , Reissman Timothy , Yu Fan , Kan Edwin C. 
Published: January 2010

AbstractA low-range pressure sensor (0-100kPa) based on the P(VDF-TrFE) piezoelectric thin film is proposed, where the long-term drift is eliminated by operating near the piezoelectric resonance. The pressure sensor is designed for blood pressure and tissue swelling pressure monitoring. The poled 50μm±1μm P(VDF-TrFE) copolymer film is used as the sensing element, with all fabrication and assembly materials biocompatible. A modified Butterworth-Van Dyke (BVD) [1] equivalent circuit model is used to characterize the sensor behavior. The pressure sensor exhibits negligible drift in weeks of operation. The device shows a sensitivity of 0.038MHz/kPa resonance frequency shift under stress, which leads to a maximum readout change of 1.1%/kPa in the present setup.
Towards NEMS Fluid Sensors Based on Suspended Nanomaterials
Authors: Jauregui Luis Angel , Lu Hao , Lou Jun , Chen Yong 
Published: January 2010

AbstractNanoelectromechanical systems (NEMS) based on nanomaterials, especially NEMS resonators made of suspended nanowires, nanotubes or nanosheets have emerged as promising devices for many sensing applications. However, operation of such NEMS resonators in liquids is usually difficult due to strong viscous damping. Here we present our progress in developing NEMS devices based on suspended nanomaterials that can operate in liquids. We present our measurements performed on suspended metallic nanowires driven by AC currents in a magnetic field in liquids.
Application of a 3D-Continuum Theory of Dislocations to a Problems of Constrained Plastic Flow: Microbending of a Thin Film
Authors: Sandfeld Stefan , Hochrainer Thomas , Zaiser Michael 
Published: January 2010

AbstractThe advancing miniaturisation of e.g. microelectronic devices leads to an increasing interest in physically motivated continuum theories of plasticity in small volumes. Such theories need to be based on the averaged dynamics of dislocations. Preserving the line-like character of these defects, however, posed serious problems for the development of dislocation-based continuum theories, while continuum theories based on scalar dislocation densities necessarily stay on a phenomenological level. Within this work we apply a dislocation-based continuum theory, which is based on a physically meaningful averaging of dislocation lines, to the benchmark problem of bending of a free-standing thin film.
(Bio)degradable Urethane-Elastomers for Electrospun Vascular Grafts
Authors: Baudis Stefan , Schwarz Maria , Grasl Christian , Bergmeister Helga , Weigel Guenter , Schima Heinrich , Liska Robert 
Published: January 2010

AbstractElectrospinning is a very powerful method to create cellular scaffolds for regenerative medicine – especially for artificial vascular grafts. Commercially available thermoplastic polyurethane elastomers (TPUs), like Pellethane™ are FDA approved and have already shown excellent biomechanical properties as electrospun vascular grafts. In order to induce the growth of a neo artery and hence increase the long-term patency of the graft, the use of biodegradable TPUs is beneficial. Therefore we aim for the development of degradable TPUs. In preliminary studies the mechanical properties of segmented TPUs were examined. The tendencies of the properties of the compression-molded bulk materials were also found for the electrospun materials. It could also be shown that the substitution of the aromatic 4,4′-methylene diphenyl diisocyanate building blocks in Pellethane™ with the aliphatic hexamethylene diisocyanate – to avoid toxic aromatic amines as degradation products - only causes minor loss of strength. To obtain degradable TPUs, our concept is to incorporate cleavable ester bonds into the polymer chain. For this purpose, lactic- and terephthalic ester-based cleavable chain extenders were used. The expected degradation products showed no cytotoxicity in-vitro. Degradation tests of polymer samples in phosphate buffered saline at elevated temperatures confirmed the degradability of the new polymers.
Synthesis and Characterization of Poly(Glycerol Sebacate) for Human Mesenchymal Response Studies
Authors: Jaafar Israd Hakim , Ammar Mohamed M. , Pearson Raymond E. , Coulter John P. , Jedlicka Sabrina S. 
Published: January 2010

AbstractCell fate modification is a critical step in preparing cells and tissues for implantation therapeutics. Novel materials possessing physical, mechanical, and chemical properties similar to those found in vivo provide a potential platform in building artificial microenvironments for therapeutic applications and well-defined biointerfaces for examining differentiation potential in stem cell biology. Poly(glycerol sebacate) (PGS), a novel biocompatible and biodegradable elastomer is one such material. With tunable mechanical properties in the range of common soft tissue, the material provides an invaluable alternative platform for use in cell-to-substrate interaction studies. This paper describes the tunability of PGS mechanical properties based on variations in curing temperatures (130, 140, and 165 °C). We characterized the material by examining properties that include equilibrium Young's modulus (E), glass transition temperature (Tg), loss factor (tan δ), degree of crosslinking, cure kinetics, protein conformational changes, and molecular bonding compositions. Variations in PGS curing temperature provide differences in physical cues presented to the hMSCs, and work is underway to examine the cellular responses of these hMSCs to microstructured PGS. Ultimately, micro- and nanostructured PGS may be useful tools in the maintenance, differentiation, and control of signaling pathways in hMSCs.
Glass Bone Implants: The Effect of Surface Topology on Attachment and Proliferation of Osteoblast Cells on 45S Bioactive Glass
Authors: Jain Raina Himani , Wang Shaojie , Moawad Hassan M. , Falk Matthias M. , Jain Himanshu 
Published: January 2010

AbstractBioglass 45S is a promising bone implant material with superior biocompatibility. Past research showed that adhesion of bone cells to titanium is strongly affected by its surface architecture. However, little is known about the role of surface topology of glass on its use as an implant. Thus, we systematically investigated the effect of surface roughness (Ra ∼ 0.01 – 1.2 μm) on cell adhesion and proliferation on 45S Bioglass in vitro. MG63 osteosarcoma and MC3T3 osteoblast precursor cells were seeded on the glass samples, and incubated for up to 6 days. The attachment, morphology and proliferation of cells were investigated using fluorescence microscopy. Our results show that cell attachment (as indicated by cell spreading and number of focal adhesion sites), and proliferation rate decrease with increasing roughness of bioactive glass surface. These findings provide important insight for improving surface characteristics of bioactive glass bone implants.
Esters of Maleic Anhydride as Both a New and Old Material for Tissue Engineering
Authors: Hedberg-Dirk Elizabeth L. , Cicotte Kirsten Nicole , Dirk Shawn M. 
Published: January 2010

AbstractMany publications have examined the biodegradable polymer poly(propylene fumerate) (PPF) for use in tissue engineering applications. We have examined a similar crosslinkable polymer system, poly(propylene fumerate)-co-(propylene maleate) (PPFcPM), derived from maleic anhydride (MA) and 1,2-propanediol (PD). Two methods were examined in order to synthesis the copolymer. In the first case, the reaction was carried out at high temperature (250°C) under nitrogen using tosic acid as the catalyst. Only PPF was identified due to the thermal isomerization of the maleate groups to the more stable fumerate group. In the second case, toluene was used as the solvent to azeotropically (85 °C) remove water and drive the acid catalyzed esterification reaction. In the lower temperature case, a small amount of fumerate (<30%) was identified. Both polymer systems had glass transition temperatures (Tg) below room temperature. The PPFcPM copolymer was electrospun and crosslinked in situ to form porous micro- and nano fiber mats. Initial biocompatibility studies have also been preformed.