bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tregs and infections: on the potential value of modifying their function
Authors: Sehrawat Sharvan , Rouse Barry T 
Published: September 2011

ABSTRACTCD4+ T cells, which express a master transcription factor, Foxp3, have been recognized as bona fide Tregs. These cells are essential to maintain immune homeostasis in healthy as well as infected mice and humans. Extensive investigations in the last decade have provided ways to manipulate the Foxp3+ Treg response therapeutically so the role of such cells in microbe-induced inflammatory reactions can be evaluated. This review focuses on our current understanding of the mechanisms required for the generation and sustenance of Tregs in vivo and the potential value of modulating Tregs to control microbe-induced immunopathological responses.
A multi-system approach to reducing insulin errors
Authors: Grant Paul 
Published: September 2011

Background Insulin prescribing and administration errors are consistently high with respect to hospital in-patients. There is no straightforward solution to the problem as there are multiple causative factors and system failures. We describe the implementation of a multi-system approach which looks at changes across the board to avoid the risk of serious harm in a teaching hospital setting. Methods Organizational level changes included addressing the development of a culture of safety and promoting management buy in. Clinical level changes relate to the labelling and storage of insulin and the provision of accessible information for clinical staff in several different formats. Patient level changes were directed at improving the prescription charts with their own specific insulin section as well as empowering patients to retain the control of their own insulin administration. Results Following the initial phase of the project the number of clinical incidents relating to insulin administration and prescribing increased by 18%. Discussion The surprising initial outcome was felt to reflect an increased awareness of the issues surrounding insulin problems and the fact that they were previously under-reported. The project has had strong support and good feedback from a wide array of healthcare professionals within the hospital trust. The national diabetes in-patient audit will allow an opportunity for further analysis and a longer time frame for the multi-system changes to bed in.
Stutter Exacerbated by Lithium in a Pediatric Patient with Bipolar Disorder
Authors: Gulack Brian C , Puri Neil V , Kim Wun J 
Published: September 2011

Objective: To report the first known case of a lithium-exacerbated stutter in a pediatric patient. Case Summary: A 10-year-old male with a history of developmental stuttering, bipolar disorder not otherwise specified (NOS), attention-deficit/hyperactivity disorder, and conduct disorder was admitted to the psychiatric hospital because of recurrent suicidal ideations and increased physical aggression toward staff at his residential facility. The patient was being treated with lithium at initial dose of 150 mg/day at bedtime for bipolar disorder NOS. When the lithium dose was increased to 900 mg twice daily to better control the bipolar symptoms, his developmental stutter worsened intensely. When the lithium dose was reduced to 60 mg in the morning and 900 mg at night, the stutter returned to baseline. No other medication changes were made during this interval. His serum lithium concentration was 0.62 mEq/L at baseline, 1.24 mEq/L during the height of his exacerbated stutter, and returned to 0.64 mEq/L after dose reduction. Discussion: To our knowledge, only 1 case lithium-exacerbated stutter has been reported to the literature, and this was in an adult. The developmental stutter of our pediatric patient worsened when he was treated with higher doses of lithium. He was on stable doses of his other medications during the adjustments to the lithium dose, malding it less likely that the stutter was due to one of these medications. However, it is possible that the exacerbation involved an interaction between lithium and one or several of the other medications. Based on the Naranjo probability scale, this case represents a probable adverse drug reaction. Conclusions: Clinicians should be aware that an additional adverse effect of lithium may be an exacerbation of stutter.
Synthesis and Characterization of BaTiO3/CoFe2O4 thin films
Authors: Andrade Helen R. C. S. , Seara Luciana M. , Mohallem Nelcy D. S. 
Published: September 2011

ABSTRACTNanocomposites formed by ferrimagnetic and ferroelectric materials are multiferroic material in which magnetoelectric coupling occurs via piezoelectricity and magnetostriction phenomena. These nanocomposites have a variety of applications in tunable microwave devices using electric control of spin wave propagation or new magnetic memories in which the magnetic response is controlled by electric field.In this work, transparent and homogeneous thin films of barium titanate interleaved with cobalt ferrite were prepared by sol–gel method using dip-coating process. Films of pure barium titanate and cobalt ferrite were also prepared for comparison. The nanocomposite films were deposited onto clean quartz substrates, where a coating of each material was deposited interleaved, where the cobalt ferrite film formed the last layer. The films were dried in air after each dipping and heated at 900 oC for 1 hour to convert the amorphous films into crystalline ones. The samples were characterized by low angle X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM) and UV-Vis spectroscopy.
High Efficiency, Large Area, Nanocrystalline Silicon Based, Triple-Junction Solar Cells
Authors: Banerjee A. , Su T. , Beglau D. , Pietka G. , Liu F. , Yan B. , Yang J. , Guha S. 
Published: September 2011

ABSTRACTWe have fabricated large-area, thin-film multijunction solar cells based on hydrogenated amorphous silicon (a-Si:H) and nanocrystalline silicon (nc-Si:H) made in a large area batch reactor. The device structure consisted of an a-Si:H/nc-Si:H/nc-Si:H stack on Ag/ZnO back reflector coated stainless steel substrate, deposited using our proprietary High Frequency (HF) glow discharge technique. For the nc-Si:H films, we investigated two deposition rate regimes: (i) low rate <1 nm/s and (ii) high rate >1 nm/s. We optimized the deposition parameters, such as pressure, gas flow, dilution, and power. We did SIMS analysis on the optimized films, and found the impurity concentrations were one order of magnitude lower than the films made with the conventional RF process. In particular, the oxygen concentration is reduced to ~1018 cm-3. This value is among the lowest oxygen concentration reported in literature. The low impurity content is attributed to proprietary cathode hardware and the optimized deposition process. During the initial optimization and investigative phase, we fabricated small-area (0.25 cm2 and 1.1 cm2) cells. The information obtained from the initial phase was used to fabricate large-area (aperture area 400 cm2) cells, and encapsulated the cells using the same flexible encapsulants that are used in our commercial product. We have light soaked the low-rate and high-rate encapsulated modules. The highest initial efficiency of the low-rate modules is 12.0% as confirmed by NREL. The highest corresponding stable efficiency attained for the low-rate samples cells is 11.35%. For the high-rate small-area (1.1 cm2) cells, the highest initial active-area efficiency and corresponding stable efficiency attained are 13.97% and 12.9%, respectively. We present the details of the research conducted to develop the low- and high-rate cells and modules.
Microscopic Characterizations of Nanostructured Silicon Thin Films for Solar Cells
Authors: Fejfar Antonín , Klapetek Petr , Zlámal Jakub , Vetushka Aliaksei , Ledinský Martin , Kočka Jan 
Published: September 2011

ABSTRACTMicroscopic characterization of mixed phase silicon thin films by conductive atomic force microscopy (C-AFM) was used to study the structure composed of conical microcrystalline grains dispersed in amorphous matrix. C-AFM experiments were interpreted using simulations of electric field and current distributions. Density of absorbed optical power was calculated by numerically solving the Maxwell equations. The goal of this study is to combine both models in order to simulate local photoconductivity for understanding the charge photogeneration and collection in nanostructured solar cells.
High-Efficiency Microcrystalline Silicon and Microcrystalline Silicon-Germanium Alloy Solar Cells
Authors: Matsui Takuya , Kondo Michio 
Published: September 2011

ABSTRACTThis paper presents our material studies on hydrogenated microcrystalline silicon (μc-Si:H) and microcrystalline silicon-germanium alloy (μc-Si1-xGex:H) thin films for the development of high efficiency p-i-n junction solar cells. In μc-Si:H solar cells, we have evaluated the structural properties of the intrinsic μc-Si:H layers grown by plasma-enhanced chemical vapor deposition at high deposition rates (>2 nm/s). Several design criteria for the device grade μc-Si:H are proposed in terms of crystallographic orientation, grain size and grain boundary passivation. Meanwhile, in μc-Si1-xGex:H solar cells, we have succeeded in boosting the infrared response of solar cell upon Ge incorporation up to x∼0.2. Nevertheless, a degradation of solar cell parameters is observed for large Ge contents (x>0.2) and thick i-layers (> 1 μm), which is attributed to the influence of the Ge dangling bonds that act as acceptorlike states in undoped μc-Si1-xGex:H. To improve the device performance, we introduce an oxygen doping technique to compensate the native defect acceptors in μc-Si1-xGex:H p-i-n solar cells.
The Role of H-Plasma in Aluminum Induced Crystallization of Amorphous Silicon
Authors: Luo Chong , Li Juan , Li He , Meng Zhiguo , Huang Qian , Xu Shengzhi , Sing Kwok Hoi , Xiong Shaozhen 
Published: September 2011

ABSTRACTA technique to improve and accelerate aluminum induced crystallization (AIC) by hydrogen plasma is proposed in this paper. Raman spectroscopy and Secondary Ion Mass Spectrometry of crystallized poly-Si thin films show that hydrogen plasma radicals reduce the crystallization time of AIC. This technique shortens the annealing time from 10 hours to 4 hours and increases the Hall mobility from 22.1 cm2/V·s to 42.5 cm2/V·s. The possible mechanism of AIC assisted by hydrogen radicals will also be discussed.
Charge-transfer doped intrinsic diamond electrochemical electrodes
Authors: Chen Waileong , Li Chiuan-Yi , Yeh Shoupu , Yei Shin-Hung , Tzeng Yonhua 
Published: September 2011

ABSTRACTWe report electrochemical characteristics of hydrogen terminated charge-transfer doped intrinsic microcrystalline diamond films. Microcrystalline diamond was synthesized by Direct- Current Plasma Enhanced Chemical Vapor Deposition (DC-PECVD) in methane diluted by hydrogen. The diamond films were subjected to further treatment by microwave plasma in pure hydrogen to increase the hydrogen termination of the diamond surfaces and their negative electron affinity. When the diamond is exposed to the ambient moisture, valance electrons tend to tunnel from the first few atomic layers of the diamond surface to the adsorbed water adlayer. This charge transfer process results in the surface of hydrogen-terminated diamond behaving like a p-type semiconductor.Electrochemical characteristics of hydrogen-terminated diamond films were exposed to an air plasma for depleting the surface hydrogen atoms and then re-hydrogenated the same diamond films with atomic hydrogen. Cyclic voltammetry in 0.1M H2S04 aqueous solution and 0.01M Fe(CN)6-4/-3+0.1M KCl aqueous solution was applied to reveal high current density and wide potential window for hydrogen-terminated diamond grown on silicon substrates. The faceted surface morphology has been observed by SEM. The crystalline characteristics and carbon phases in the diamond film were examined by Raman spectroscopy.
Ellipsometric characterization of thin nanocomposite films with tunable refractive index for biochemical sensors
Authors: Petrik P. , Egger H. , Eiden S. , Agocs E. , Fried M. , Pecz B. , Kolari K. , Aalto T. , Horvath R. , Giannone D. 
Published: September 2011

ABSTRACTCreating optical quality thin films with a high refractive index is increasingly important for waveguide sensor applications. In this study, we present optical models to measure the layer thickness, vertical and lateral homogeneity, the refractive index and the extinction coefficients of the polymer films with nanocrystal inclusions using spectroscopic ellipsometry. The optical properties can be determined in a broad wavelength range from 190 to 1700 nm. The sensitivity of spectroscopic ellipsometry allows a detailed characterization of the nanostructure of the layer, i.e. the surface roughness down to the nm scale, the interface properties, the optical density profile within the layer, and any other optical parameters that can be modeled in a proper and consistent way. In case of larger than about 50 nm particles even the particle size can be determined from the onset of depolarization due to light scattering. Besides the refractive index, the extinction coefficient, being a critical parameter for waveguiding layers, was also determined in a broad wavelength range. Using the above information from the ellipsometric models the preparation conditions can be identified. A range of samples were investigated including doctor bladed films using TiO2 nanoparticles.
“Graphene-Like” Exfoliation of Quasi-2D Crystals of Titanium Ditelluride: A New Route to Charge Density Wave Materials
Authors: Khan Javed M. , Teweldebrhan Desalegne , Nolen Craig M. , Balandin Alexander. A. 
Published: September 2011

ABSTRACTWe used a “graphene-like” mechanical exfoliation to obtain atomically thin films of TiTe2. The building blocks of titanium ditelluride are atomic tri-layers separated by the van der Waals gaps. The exfoliation procedure allows one to obtain the few-atom-thick films with strong confinement of charge carriers and phonons. We have verified the crystallinity of the exfoliated films and fabricated the back-gated field-effect devices. The current – voltage characteristics of the TiTe2devices revealed strong non-linearity, which suggests the charge-density wave effects. The obtained results are important for the proposed application of TiTe2for the charge-density wave devices and thermoelectric energy conversion.
Crystallographic Processing of Scanning Tunneling Microscopy Images of Cobalt Phthalocyanines on Silver and Graphite
Authors: Moeck P. , Straton J. , Toader M. , Hietschold M. 
Published: September 2011

ABSTRACTMonolayers of cobalt phthalocyanine (CoPc) and fluorinated cobalt phthalocyanine (F16CoPc) on silver (111) and on highly (0001) oriented pyrolytic graphite (HOPG) were imaged with a scanning tunneling microscope (STM) at cryogenic temperatures (around 30 K) at Chemnitz University of Technology. Domains of regular arrays with periodicity in two dimensions (2D) and a variety of plane symmetries were observed. Crystallographic image processing (CIP) was used to quantify deviations from the plane symmetry groups and to obtain symmetrized versions of the content of the average unit cells of some of these arrays. Conclusions on the point symmetry of the CoPc and F16CoPc molecules within the arrays were drawn.
Measurement of Piezoelectric Transverse and Longitudinal Displacement with Atomic Force Microscopy for PZT Thick Films
Authors: Kashiwagi Yuta , Iijima Takashi , Aiso Toru , Yamamoto Takashi , Nishida Ken , Funakubo Hiroshi , Nakajima Takashi , Okamura Soichiro 
Published: September 2011

ABSTRACTThe actual transverse and longitudinal displacement of PZT thick film was measured using a newly developed atomic force microscopy (AFM). The AFM is attached a feedback circuit named “torsion feedback”. The torsion and Z-height feedback circuits control an AFM cantilever to follow piezoelectric deformation of the sample. To measure transverse displacement, the cantilever contacts the edge of sample. The transverse displacement is determined from the torsion feedback signal absolutely. To measure longitudinal displacement, the cantilever contacts the center of sample. The longitudinal displacement is determined from Z-height feedback signal absolutely. A 5-μm-thick PZT film was prepared on Pt/Ti/SiO2/Si substrates. The film sample was shaped square pillar. The side electrode length (L) of square pillar shaped sample was ranged from 1000 μm to 10 μm. The relation between side electrode length and the transverse or the longitudinal displacements were investigated. With decreasingL, the transverse displacement decreased nonlinearly, and the longitudinal displacement increased nonlinearly. The finite element method (FEM) simulation suggests that the substrate clamped PZT film behaved nonlinearly. The effective -d31andd33were calculated from the measured displacement, and these values increase with decreasingL. The effectived33and -d31showed correlation, and the ratio wasd33: -d31= 5.3 : 1 , whereas the bulk ratioisd33: -d31= 2.4 : 1.This result suggests that the substrate clamping effect of the transverse displacement was larger than that of the longitudinal displacement.
The Local Structure and I-V Characteristics of Chromium Doped Semiconducting Boron Carbide
Authors: Liu Jing , Dowben P. A. , Luo Guangfu , Mei Wai-Ning , Rajapitamahuni Anil Kumar , Sokolov Andre , Karki Sudarshan , Caruso Anthony N. 
Published: September 2011

ABSTRACTThe local spin configuration and band structure of chromium doped boron carbide calculated by density functional theory suggests local magnetic ordering. While the long range dopant position appears random in the boron carbide semiconductor, the local position and initial empirical/computational results suggest the promise of large magneto-resistive effects. The chromium doped boron carbide thin films, fabricated by boron carbide-chromium co-deposition, were studied by current-voltage (I-V) characteristics measurements. The results provide some reason to believe that magneto-resistive effects are indeed present at room temperature.
Ab InitioStructure Characterization for the Amorphous Assembly of Si Clusters Encapsulating Transition Metal
Authors: Miyazaki Takehide , Uchida Noriyuki , Kanayama Toshihiko 
Published: September 2011

ABSTRACTWe present a first-principles lattice dynamics for the assembly of the transition-metal (M)-encapsulated Sinclusters in amorphous phase (a-MSin), which has been proposed as a potential candidate for the channel material of the next-generation thin-film transistors (TFTs) [N. Uchidaet al.,Appl. Phys. Express1, 121502 (2008)]. The shape of calculated vibrational density of states (VDOS) curve of a-MoSi10is similar to the counterpart of the high pressure phase of a-Si (HPA-Si) although the present systems are obtained as a result of pressure relaxation. Its radial distribution function (RDF) among Si themselves is characterized by the absence of a gap between the first and second shells, which is also the case in . We further present the VDOS of a-WSi10, whose curve shape is again similar to that of HPA-Si. A difference between a-MoSi10and a-WSi10is that the W-atom displacement components extracted from the vibration eigenvectors are mainly distributed over a lower frequency range (< ~ 150 cm-1) than the Mo counterpart (~ 150 cm-1to ~ 300 cm-1). This may be attributed to a larger atomic mass of W than Mo.
Application of a Dual-spectral-range, Divergent-beam Spectroscopic Ellipsometer for High-Speed Mapping of Large-area, Laterally-inhomogeneous, Photovoltaic Multilayers
Authors: Fried M. , Juhasz G. , Major C. , Nemeth A. , Petrik P. , Polgar O. , Salupo C. , Dahal Lila R. , Collins R. W. 
Published: September 2011

ABSTRACTWe have developed a prototype spectroscopic ellipsometer for imaging/mapping purposes requiring only one measurement cycle (one rotation period of a polarizer or analyzer) for the acquisition of a two-dimensional array of data points. Our new measurement technique serves as a novel form of imaging ellipsometry, using a divergent (uncollimated, diffuse) source system and a detection system consisting of an angle-of-incidence-sensitive pinhole camera. By incorporating broad-band sources and wavelength dispersion optics, the instrument provides continuous high-resolution spectra along a line image of the sample surface. As a result, information on multilayer photovoltaics stacks can be obtained over large areas (several dm2) at high speed. The technique can be expanded to even larger areas by scaling-up the optical geometry. The spatial resolution of the line image is limited by the minimum resolved-angle as determined by the detection system. Small-aperture polarizers (25 mm diameter) are incorporated into the instrument, which reduces its cost. Demonstration mapping measurements have been performed ex situ on a multilayer sample deposited on a polymer substrate, including an intentionally graded 80-350 nm thick hydrogenated amorphous silicon (a-Si:H) layer and an intended uniform 400-500 nm thick transparent conducting ZnO:Al layer, both on opaque silver. Alternative commercial instruments for ex situ SE mapping must translate the sample in two dimensions. Even a 15 x 15 cm2 sample requires > 200 measurements with cm-resolution and at least 15 min. By collecting ex situ data in parallel along one dimension through imaging, the divergent-beam system can measure with similar spatial resolution in < 2 min. In situ measurements on both roll-to-roll polymer and rigid glass will be possible in the future.
Development of lead-free materials for piezoelectric energy harvesting
Authors: Rai R. , Coondoo I. , Lopes R. P. , Bdikin I. , Ayouchi R. , Bhattacharaya S. , Schwarz R. , Kholkin A. L. 
Published: September 2011

ABSTRACTMechanical energy harvesting from ambient vibrations is an attractive renewable source of energy for various applications. Prior research was solely based on lead-containing materials which are detrimental to the environment and health. Therefore, lead-free materials are becoming more attractive for harvesting applications. The present work is focused on the development of lead-free piezoelectric materials based on solid solution having composition (KNa)NbO3-xABO3, (where A = Li, and B = Nb; x = 0, 5, 5.5, 6, and 6.5 wt%). The solid solutions of the above ceramics were prepared by using solid-state reaction method. The X-ray diffraction spectra exhibited single phase formation and good crystallinity with LiNbO3 addition up to x = 6.5 wt%. Dielectric studies reveal that the composition with LiNbO3 = 6.5 wt% exhibits superior properties suitable for piezoelectric energy harvesting applications. The nanoscale piezoelectric data obtained with piezoresponse force microscopy provide a direct evidence of strong piezoelectricity with LN doping. The best piezoelectric properties are obtained for the composition K0.5Na0.5NbO3 – 6.5%LiNbO3.