bluuebunny/crossref_metadata_2025 huggingface dataset:
Interleukin-17-Mediated Control of Parasitemia in ExperimentalTrypanosoma congolenseInfection in Mice
Authors: Mou Zhirong , Jia Ping , Kuriakose Shiby , Khadem Forough , Uzonna Jude E.
Published: September 2010

BALB/c mice are highly susceptible to experimentalTrypanosoma congolenseinfections, whereas C57BL/6 mice are relatively resistant. Infected highly susceptible BALB/c mice die of systemic inflammatory response syndrome. Because interleukin-17 (IL-17) and Th17 cells regulate inflammatory responses, we investigated their role in the pathogenesis of experimental African trypanosomiasis in mice. We show that the production of IL-17 by spleen and liver cells and the serum IL-17 level increased afterT. congolenseinfection in mice. Interestingly, infected highly susceptible BALB/c mice produced more IL-17 and had more Th17 cells than infected relatively resistant C57BL/6 mice. Paradoxically, neutralization of IL-17 with anti-IL-17 monoclonal antibodyin vivoinduced higher parasitemia in both the susceptible and the relatively resistant mice. Interestingly, anti-IL-17 antibody-treated mice had higher serum levels of alanine aminotransferase and aspartate aminotransferase, and the production of IL-10 and nitric oxide by liver cells was markedly decreased. Moreover, recombinant IL-17-treated mice exhibited significantly faster parasite control and lower peak parasitemia compared to control mice. Collectively, these results suggest that the IL-17/Th17 axis plays a protective role in murine experimental African trypanosomiasis.
Constitutive MEK1 Activation Rescues Anthrax Lethal Toxin-Induced Vascular Effects
In Vivo
Authors: Bolcome Robert E. , Chan Joanne
Published: September 2010

Anthrax lethal toxin (LT) increases vascular leakage in a number of mammalian models and in human anthrax disease. Using a zebrafish model, we determined that vascular delivery of LT increased permeability, which was phenocopied by treatment with a selective chemical inhibitor of MEK1 and MEK2 (also known as mitogen-activated protein kinase [MAPK] kinase, MEK, or MKK). Here we investigate further the role of MEK1/phospho-ERK (pERK) in the action of LT. Overexpression of wild-type zebrafish MEK1 at high levels did not induce detrimental effects. However, a constitutively activated version, MEK1
S219D,S223D
(MEK1DD), induced early defects in embryonic development that correlated with increased ERK/MAPK phosphorylation. To bypass these early developmental defects and to provide a genetic tool for examining the action of lethal factor (LF), we generated inducible transgenic zebrafish lines expressing either wild-type or activated MEK1 under the control of a heat shock promoter. Remarkably, induction of MEK1DD transgene expression prior to LT delivery prevented vascular damage, while the wild-type MEK1 line did not. In the presence of both LT and MEK1DD transgene expression, cardiovascular development and function proceeded normally in most embryos. The resistance to microsphere leakage in transgenic animals demonstrated a protective role against LT-induced vascular permeability. A consistent increase in ERK phosphorylation among LT-resistant MEK1DD transgenic animals provided additional confirmation of transgene activation. These findings provide a novel genetic approach to examine mechanism of action of LT
in vivo
through one of its known targets. This approach may be generally applied to investigate additional pathogen-host interactions and to provide mechanistic insights into host signaling pathways affected by pathogen entry.
Entamoeba histolytica
Infection and Secreted Proteins Proteolytically Damage Enteric Neurons
Authors: Lourenssen Sandra , Houpt Eric R. , Chadee Kris , Blennerhassett Michael G.
Published: September 2010

The enteric protozoan parasite
Entamoeba histolytica
causes amebic colitis through disruption of the mucus layer, followed by binding to and destruction of epithelial cells. However, it is not known whether ameba infections or ameba components can directly affect the enteric nervous system. Analysis of mucosal innervations in the mouse model of cecal amebiasis showed that axon density was diminished to less than 25% of control. To determine whether amebas directly contributed to axon loss, we tested the effect of either
E. histolytica
secreted products (Eh-SEC) or soluble components (Eh-SOL) to an established coculture model of myenteric neurons, glia, and smooth muscle cells. Neuronal survival and axonal degeneration were measured after 48 h of exposure to graded doses of Eh-SEC or Eh-SOL (10 to 80 μg/ml). The addition of 80 μg of either component/ml decreased the neuron number by 30%, whereas the axon number was decreased by 50%. Cytotoxicity was specific to the neuronal population, since the glial and smooth muscle cell number remained similar to that of the control, and was completely abrogated by prior heat denaturation. Neuronal damage was partially prevented by the cysteine protease inhibitor E-64, showing that a heat-labile protease was involved.
E. histolytica
lysates derived from amebas deficient in the major secreted protease
EhCP5
caused a neurotoxicity similar to that of wild-type amebas. We conclude that
E. histolytica
infection and ameba protease activity can cause selective damage to enteric neurons.
The Capsular Serotype ofStreptococcus pneumoniaeIs More Important than the Genetic Background for Resistance to Complement
Authors: Melin Merit , Trzciński Krzysztof , Meri Seppo , Käyhty Helena , Väkeväinen Merja
Published: September 2010

The polysaccharide capsule ofStreptococcus pneumoniaeinhibits phagocytic killing by innate immune mechanisms. Certain serotypes are associated with invasive disease while others with a nasopharyngeal carriage. The invasiveness of serotypes may partly be explained by ability to resist deposition of complement (C3) on the bacterial surface and consequent opsonophagocytic killing. In our previous studies, we observed that clinical isolates of serotypes 1 and 5, which are rarely detected in asymptomatic carriage, were resistant to complement deposition and opsonophagocytosis, whereas serotypes 6B and 23F, both common in carriage, were more sensitive to deposition of C3 and opsonophagocytic killing. However, presence of significant variation in C3 deposition between isolates of the same serotype indicated that factors other than the capsule also affect complement resistance. To distinguish the relative effect of the capsular serotype and other virulence factors on C3 deposition, we compared capsule-switched mutants prepared in genetic backgrounds of pneumococcal strains TIGR4, 603, and 618. Clinical isolates which had the same multilocus sequence type but expressed different serotypes were also compared. We found that the serotype had a significant impact on complement resistance and that the more resistant the strain was to complement, the higher was the concentration of polysaccharide-specific antibodies required for opsonophagocytic killing. Comparison of strains expressing the same capsular polysaccharides in the different genetic backgrounds and various capsular mutants of the same strain suggests that while the genotype affects complement resistance, the serotype is the most important determinant. Differences between serotypes were more significant than the differences between strains.
Reading epilepsy
Authors: Miller Sarah , Razvi Saif , Russell Aline
Published: September 2010

Reading epilepsy is a rare epilepsy syndrome triggered by language related activity, in particular reading. Here we describe a patient with reflex seizures brought on specifically by reading in Arabic. The types of reading epilepsy, their typical clinical features, probable pathophysiology and management are discussed.
Tourette's syndrome and other tic disorders
Authors: Rickards Hugh
Published: September 2010

Tourette's syndrome is a neuropsychiatric disorder characterised by motor and phonic tics. Although tics are common in children, only about 1% of those affected meet the criteria for Tourette's syndrome, and many are not disabled by it. Associated problems such as attention deficit hyperactivity disorder and obsessive–compulsive disorders can often be more disabling than the tics themselves. People with Tourette's tend to be worst in their teenage years but improve in adulthood. The cause is unknown but there are strong genetic factors. Treatment should be aimed at minimising disability and includes social, psychological and biological approaches.
Mortality in Vermont granite workers and its association with silica exposure
Authors: Vacek Pamela M , Verma Dave K , Graham William G , Callas Peter W , Gibbs Graham W
Published: September 2010

Objectives

To assess mortality in Vermont granite workers and examine relationships between silica exposure and mortality from lung cancer, kidney cancer, non-malignant kidney disease, silicosis and other non-malignant respiratory disease.

Methods

Workers employed between 1947 and 1998 were identified. Exposures were estimated using a job–exposure matrix. Mortality was assessed through 2004 and standardised mortality ratios (SMRs) were computed. Associations between mortality and exposure to silica were assessed by nested case–control analyses using conditional logistic regression.

Results

7052 workers had sufficient data for statistical analysis. SMRs were significantly elevated for lung cancer (SMR 1.37, 95% CI 1.23 to 1.52), silicosis (SMR 59.13, 95% CI 44.55 to 76.97), tuberculosis (SMR 21.74, 95% CI 18.37 to 25.56) and other non-malignant respiratory disease (SMR 1.74, 95% CI 1.50 to 2.02) but not for kidney cancer or non-malignant kidney disease. In nested case–control analyses, significant associations with cumulative exposure to respirable free silica were observed for silicosis (OR 1.13, 95% CI 1.05 to 1.21 for each 1 mg/m3-year increase in cumulative exposure) and other non-malignant respiratory disease (OR 1.10, 95% CI 1.03 to 1.16) but not for lung cancer (OR 0.99, 95% CI 0.94 to 1.03), kidney cancer (OR 0.96, 95% CI 0.84 to 1.09) or non-malignant kidney disease (OR 0.95, 95% CI 0.84 to 1.08).

Conclusions

Exposure to crystalline silica in Vermont granite workers was associated with increased mortality from silicosis and other non-malignant respiratory disease, but there was no evidence that increased lung cancer mortality in the cohort was due to exposure. Mortality from malignant and non-malignant kidney disease was not significantly increased or associated with exposure.
COPING WITH DECOHERENCE: PARALLELIZING THE QUANTUM FOURIER TRANSFORM
Authors: NAGY MARIUS , AKL SELIM G.
Published: September 2010

Rank-varying computational complexity describes those computations in which the complexity of executing each step is not a constant, but evolves throughout the computation as a function of the order of execution of each step [2]. This paper identifies practical instances of this computational paradigm in the procedures for computing the quantum Fourier transform and its inverse. It is shown herein that under the constraints imposed by quantum decoherence, only a parallel approach can guarantee a reliable solution or, alternatively, improve scalability.
ENTANGLEMENT VERIFICATION WITH AN APPLICATION TO QUANTUM KEY DISTRIBUTION PROTOCOLS
Authors: NAGY MARIUS , AKL SELIM G.
Published: September 2010

We develop an entanglement verification method not based on Bell inequalities, that achieves a higher reliability per number of qubits tested than existing procedures of this kind. Used in a quantum cryptographic context, the method gives rise to a new protocol for distributing classical keys through insecure quantum channels. The cost of quantum and classical communication is significantly reduced in the new protocol, while its security is increased with respect to other entanglement-based protocols exchanging the same number of qubits. To achieve this performance, our scheme relies on a simple quantum circuit and the ability to store qubits.
ONE-TIME PADS WITHOUT PRIOR ENCOUNTER
Authors: NAGY NAYA , AKL SELIM G.
Published: September 2010

Using one-time pads is the only cryptographic solution that really ensures the secrecy of a transmitted message. The communicating parties have to meet in advance to establish the value of any one-time pad. This means that the two parties have to meet regularly to renew the batch of one-time pads they share. By contrast, we show that after developing a secret reading mask using any quantum key distribution algorithm, the two parties can communicate indefinitely by encrypting each of their messages with a one-time pad. The value of the one-time pad is quantum encrypted and transmitted prior to the transmission of the message itself.
SEMICLASSICAL ANALYSIS OF DEFECT SINE–GORDON THEORY
Authors: NEMES F.
Published: September 2010

The classical sine–Gordon model is a two-dimensional integrable field theory, with particle-like solutions — the so-called solitons. Using its integrability one can define the quantum theory without the process of canonical quantization. The bootstrap method employs the fundamental properties of the model to restrict the structure of the scattering matrix as far as possible. The classical model can be extended with integrable discontinuities, purely transmitting jump defects. Then the quantum version of the extended model can be determined via the bootstrap method again. The resulting quantum theory contains the so-called CDD uncertainty. The aim of this article is to carry out the semiclassical approximation on both the classical and the quantum side of the defect sine–Gordon theory. The CDD ambiguity can be restricted by comparing the two results. To complete the comparison we have to calculate the relation between the classical and quantum parameters. We determine the quantum parameters from the poles of the T matrix, and we find that there are resonances in the spectrum.
HOLOGRAPHIC EXPERIMENTS ON DEFECTS
Authors: WAPLER MATTHIAS C.
Published: September 2010

Using the AdS/CFT correspondence, we study the anisotropic charge transport properties of both supersymmetric and nonsupersymmetric matter fields on (2+1)-dimensional defects coupled to a (3+1)-dimensional [Formula: see text] "heat bath." We focus on the cases of a finite external background magnetic field, finite net charge density and finite mass and their combinations. In this context, we also discuss the limitations due to operator mixing that appears in a few situations and that we ignore in our analysis. At high frequencies, we discover a spectrum of quasiparticle resonances due to the magnetic field and finite density and at small frequencies, we perform a Drude-like expansion around the DC limit. Both of these regimes display many generic features and some features that we attribute to strong coupling, such as a minimum DC conductivity and an unusual behavior of the "cyclotron" and plasmon frequencies, which become related to the resonances found in the conformal case in an earlier paper. We further study the hydrodynamic regime and the relaxation properties, from which the system displays a set of different possible transitions to the collisionless regime. The mass dependence can be cast in two regimes: a generic relativistic behavior dominated by the UV and a nonlinear hydrodynamic behavior dominated by the IR. In the massless case, we furthermore extend earlier results from the literature to find an interesting selfduality under a transformation of the conductivity and the exchange of density and magnetic field.
A PROBLEM IN VIRTUAL GRAVITON EXCHANGES IN FLAT LARGE EXTRA DIMENSIONS
Authors: NAMATAME HARUKA
Published: September 2010

It is pointed out in a class of models with large extra dimensions that the cross-section of processes with virtual Kaluza–Klein graviton exchanges becomes either much smaller or much larger by many orders of magnitude than what is expected from that of the on-shell production of the Kaluza–Klein gravitons. We demonstrate how the problem arises using a toy model. The cause of this new problem lies in the fact that we do not have momentum conservation in the extra dimensions. To search for the signal of the large extra dimensions with high energy collider experiments, we need more care in interpreting the earlier results on the cross-sections of these processes.
CLASSICAL CELLULAR AUTOMATA AND QUANTUM FIELD THEORY
Authors: 'T HOOFT GERARD
Published: September 2010

It is pointed out that a mathematical relation exists between cellular automata and quantum field theories. Although the proofs are far from perfect, they do suggest a new look at the origin of quantum mechanics, and an essential role for the gravitational force in these considerations is suspected.
FEATURES OF SEEPAGE OF A LIQUID TO A CHINK IN THE CRACKED DEFORMABLE LAYER
Authors: ALEROEV T. S. , ALEROEVA H. T. , HUANG JIANFEI , NIE NINGMING , TANG YIFA , ZHANG SIYAN
Published: September 2010

We establish a new model for seepage of a liquid to a chink in the cracked deformable layer, an initial value problem of nonlinear fractional differential equation with variable coefficients, then design a numerical scheme of order 2 to solve this initial value problem. This new model theoretically explains the operating thickness H of a layer depending on the values of pressure gradient on the whole chink rather than on one point, which is practiced by a large amount of data. Compared with the Dontsov equation, our fractional model considers more aspects of the whole process. The earlier rejected results can also be considered in the display lines of the fractional model.
FUZZY TECHNIQUE FOR OPTIMIZATION OF OBJECTIVE FUNCTION WITH UNCERTAIN RESOURCE VARIABLES AND TECHNOLOGICAL COEFFICIENTS
Authors: VASANT PANDIAN , ELAMVAZUTHI IRRAIVAN , WEBB JEFFREY F.
Published: September 2010

In this paper, a new fuzzy optimization based on methodology utilizing a modified s-curve membership function has been applied to an industrial production problem in an oil company. The major contribution of this paper is the optimization of a profit function with respect to uncertain resource variables and technological coefficients. Three cases have been thoroughly studied in this paper. Comparative results have been successfully obtained for these three cases. This piece of information will be very important for the decision makers in implementing their decisions in a vague environment. It will be shown that there are many advantages of using the modified s-curve membership to optimize the profit function used by the decision maker; in particular strategic and flexible decisions are facilitated.
FINITE ELEMENT MODELING OF DAMPING CAPACITY IN NANO-CRYSTALLINE MATERIALS
Authors: YADOLLAHPOUR M. , ZIAEI-RAD S. , KARIMZADEH F.
Published: September 2010

Plastic deformation of materials is a major source of energy dissipation during external loading. In nano-crystalline (NC) materials, local plastic strain may arise even if the overall external load is below the yield stress of the material because of the grain structure. In this paper, the damping capacity of nano-crystalline materials is modeled by considering the grain structure. First, the grains are modeled by using a composite model. The composite model takes each oriented crystal and its immediate boundary to form a pair. Next, the finite element method in conjunction with the composite model is employed to evaluate the energy dissipation of nano-crystalline material under cyclic loading. The influence of the grain size and the external loading on the energy dissipation is investigated numerically. Energy dissipation in each of the two parts (i.e. grain and grain boundary) is also calculated as an attempt to understand the effect of grain boundary on energy dissipation.
COST ESTIMATION OF ADVANCE RESERVATIONS OVER QUEUED JOBS: A QUANTITATIVE STUDY
Authors: ZHAO CHUNJIANG , CAO JUNWEI , WU HUARUI , ZHANG FAN
Published: September 2010

A grid is a geographically distributed resource sharing environment across multiple organizations. The most typical grid resources are clusters with high performance/cost ratio. In general, these clusters are shared as non-dedicated grid resources since local users may run their jobs simultaneously. Local jobs are usually queued and processed in a batch mode with uncertain waiting time, while grid jobs always require advance reservations with guaranteed resource allocation.

In this paper, we provide quantitative analysis on the impact of advance reservations over queued jobs, in terms of job waiting time and resource utilization, respectively. It is observed that advance reservations will lead to longer job waiting time and lower resource utilization. That is to say, advance reservations should cost more than queued jobs. In this work, based on quantitative experimental results, an empirical formula for cost estimation of advance reservations over queued jobs is presented. It is suggested that compared with queued jobs, advance reservations should be doubly charged to compensate resource utilization loss. If the notice time of an advance reservation is short below a threshold, additional cost should be applied further since queue waiting time is increased.
On Degradation Studies of III–V Compound Semiconductor Optical Devices over Three Decades: Focusing on Gradual Degradation
Authors: Ueda Osamu
Published: September 2010

This paper describes studies on the reliability of semiconductor optical devices over the course of more than three decades, dating back to the early 1970s. First, a retrospective look is taken at the evolution of optical device development and reliability studies. Second, the three main degradation modes for optical devices (rapid degradation, gradual degradation, and catastrophic failure) are outlined. Third, the results of the classical research into rapid degradation that was carried out in the 1970s and 1980s are presented as an introduction to a systematic discussion of the research that followed–remarkable research into gradual degradation.
Stress and Defect Distribution of Thick GaN Film Homoepitaxially Regrown on Free-Standing GaN by Hydride Vapor Phase Epitaxy
Authors: Chen Kuei-Ming , Yeh Yen-Hsien , Wu Yin-Hao , Chiang Chen-Hao , Yang Din-Ru , Gao Zhong-Shan , Chao Chu-Li , Chi Tung-Wei , Fang Yen-Hsang , Tsay Jenq-Dar , Lee Wei-I
Published: September 2010

A 220-µm-thick Gallium nitride (GaN) layer was homoepitaxially regrown on the Ga-polar face of a 200-µm-thick free-standingc-plane GaN by hydride vapor-phase epitaxy (HVPE). The boundary of the biaxial stress distribution in the GaN substrate after regrowth was clearly distinguished. One half part, the regrown GaN, was found to be more compressive than the other half part, the free-standing GaN. Additionally, the densities of the screw and mixed dislocations reduced from 2.4 ×107to 6 ×106cm-2after regrowth. Furthermore, the yellow band emission almost disappeared, accompanied by a peak emission at approximately 380 nm related to the edge dislocation was under slightly improved in regrown GaN. We conclude that the reduction of the dislocation defects and Ga vacancies and/or O impurities are the two main reasons for the higher compressive stress in the regrown GaN than in the free-standing GaN, causing the curvature of the GaN substrate to be twice concave after regrowth.
Enhanced Optical Output Power of Tunnel Junction GaN-Based Light Emitting Diodes with Transparent Conducting Al and Ga-Codoped ZnO Thin Films
Authors: Kim Tae Hoon , Ju Young-Gu , Park Lee Soon , Lee Sang Hern , Baek Jong Hyeob , Yu Young Moon
Published: September 2010

High quality Al and Ga-codoped ZnO (AGZO) thin films were successfully deposited both on sapphire substrates and GaN-based light emitting diodes (LED) with a tunnel junction (TJ) layer by using the radio frequency magnetron sputtering technique at room temperature. The AGZO thin films grown on sapphire substrate showed high transparency (96.3% at 460 nm) and low resistivity (6.8 ×10-4Ω cm). The AGZO thin films deposited on the GaN-based LED with a TJ layer exhibited weak ohmic behavior although it improved slightly with the annealing. The optical output power of the TJ GaN-based LED with an AGZO transparent conducting layer was about 12.6 mW at 20 mA, and the external quantum efficiency was 23.0%. These values are approximately 1.7 times larger than that of the TJ GaN-based LED with a conventional Ni/Au layer.
Microstructure and Properties of a (Bi0.95Na0.75K0.15Li0.05)0.5Ba0.05TiO3 Ceramic Thick Film Prepared by Electrophoretic Deposition
Authors: Lee Dae-Su , Jeong Soon-Jong , Kim Min-Soo
Published: September 2010

The changes in the microstructure and properties of a (Bi0.95Na0.75k0.15Li0.05)0.5Ba0.05TiO3 (BNKLT–BT) ceramic film were investigated when the ceramic film was deposited with the addition of platelike SrTiO3 (STO) via an electrophoretic deposition method. The platelike SrTiO3 (STO) was used as a template for inducing grain growth with a preferential orientation of [001], and as a protective plate for restraining some elements in the film from evaporating under heat treatment. The SrTiO3 templates were found to be an effective protective layer for restraining the evaporation of volatile elements when the templates are placed on the ceramic thick film. The STO/BNKLT–BT/STO/AgPd/Al2O3 samples were fabricated and heated at 1170 °C for 12 h. They showed a [001]-oriented texture structure and better ferroelectric properties. The textured microstructure could be observed with the occurrence of grain growth around the templates. When the maximum E (E
max) was 150 kV/cm, the textured film showed a remanent polarization (P
r) of 9 µC/cm2, which was larger than that of the nontextured film. The piezoelectric strain constant (d
33
*) derived from the slope of the strain curve was 62 pm/V for the textured film, which was 1.5 times that of the nontextured film.
Dynamic Responses of Photoconduction in TiOx Films Prepared by Radio Frequency Magnetron Sputtering
Authors: Sakaguchi Koichi , Shimakawa Koichi , Hatanaka Yoshinori
Published: September 2010

The photoexcitation and decay of photoconduction with UV irradiation have been studied in titanium oxide films prepared by the rf magnetron sputtering. Dynamic responses of photocurrent are represented by a stretched exponential function, and a long-term photocurrent decay suggests that the photoexcited carriers recombine under potential fluctuations (band-edge modulations of the conduction and valence bands). Important physical parameters related to the band-edge profiles are given by our proposed model.
Excess Capacitance Due to Minority Carrier Injection in CrSi2/p-Type Crystalline Si Isotype Junction
Authors: Özdemir Orhan , Yilmazer U. Deneb , Tatar Beyhan , Ürgen Mustafa , Kutlu Kubilay
Published: September 2010

Excess current and capacitance phenonema were observed for the first time on a CrSi2/p-type crystalline silicon junction produced by cathodic arc physical vapor deposition. The heterojunction was investigated by current–voltage–temperature (I–V–T) and capacitance (conductance)–voltage/temperature (C,G–V/T) measurements for the purpose of studying transport and storage features. Excess current, manifested as a crossover at a large forward bias, was observed in I–V–T curves since minority carriers injected into the quasi-neutral region of p-c-Si were neutralized by majority carriers supplied from the p-c-Si semiconductor side. This phenomenon, known as conductivity modulation, appeared distinctly as a hump in C–V/T curves (storage property); a sharp rise in capacitance towards a maximum value as forward bias increased and the subsequent fall after a specific value. For reverse and low forward bias regions, where minority carrier injection was negligible, geometrical junction capacitance and a shoulder in C–V/T curves were observed. In the voltage range where the peak was observed in C–V/T measurements, trap-assisted tunneling recombination generation and space-charge-limited current (SCLC) mechanisms were determined in the CrSi2/p-c-Si isotype junction. Traps introduced during tunneling were identified as bulk point defects due to the chromium–boron (Cr–B) complex for the CrSi2/p-c-Si junction on the Si side by I–V–T and C(G)–T analyses. This finding seemed to be in agreement with a recent DLTS [Deep Level Transient Spectroscopy] measurement in terms of both energy depth (0.26 eV) and bulk nature. Finally, the shoulder in C–V/T curves indicated Cr–B point defects in the measurement.
Nanoscale Observation of Poling Behaviors in Nd-Substituted Bi4Ti3O12 Ferroelectric Thin Films
Authors: Shin Ran Hee , Lee Ji Hye , Kim Gracia , Jo William , Kim Dae Hyun , Lee Hyun Jin , Kang Jeongsoo
Published: September 2010

In this study, the effects of oxygen vacancies on the local poling properties of Bi-layered ferroelectric thin films were examined. Bi3.15Nd0.85Ti3O12 (BNT) thin films were coated on Pt(111)/Ti/SiO2/Si substrates using a sol–gel method. An oxygen vacancy of 2.4±0.5% was observed mainly at the Bi2O2
2+ layers in the film that annealed in an oxygen-deficient atmosphere. The film containing oxygen vacancies showed a shift in the polarization–electric field hysteresis loop. Contact-mode electrostatic force microscopy revealed a domain pinning behavior in the BNT film with oxygen vacancies. The unpolarized domains were explained by the built-in field formed by the oxygen vacancies in the Bi2O2
2+ layers.
Enhanced Light Extraction in GaN-Based Light-Emitting Diodes with Holographically Fabricated Concave Hemisphere-Shaped Patterning on Indium–Tin-Oxide Layer
Authors: Seo Tae Hoon , Oh Tae Su , Lee Yong Seok , Jeong Hyun , Kim Jan Di , Kim Hun , Park Ah Hyun , Lee Kang Jea , Hong Chang-Hee , Suh Eun-Kyung
Published: September 2010

The enhanced light extraction of the GaN-based light-emitting diode (LED) with a two-dimensional concave hemisphere-shaped indium–tin-oxide (ITO) layer, fabricated using laser holographic lithography and inductively-coupled plasma etching techniques were studied. Compared to the LED with a planar ITO layer, it is found that the light output power of LEDs with concave hemisphere patterned ITO layers is improved by ∼34%. This enhanced light output power is attributed to the increase of light extraction by effective photon escape and self-divergence effect at the concave hemisphere-shaped ITO surface.
Deformable Microdroplet Cavity Fabricated by an Inkjet Method
Authors: Saito Mitsunori , Koyama Kentaro
Published: September 2010

A droplet-elastomer compound was fabricated by using an inkjet technique. Being emitted by a nozzle, a dye-doped surfactant self-formed a microsphere in a polysiloxane elastomer. Rapid vaporization during the droplet flight process was utilized advantageously to form a small sphere. The droplet volume was controlled between 1 and 103 pl, corresponding to a diameter range of 10–120 µm. When the droplet was excited by a 532 nm laser pulse, resonance peaks of whispering gallery modes appeared in the fluorescence spectrum. The peak wavelength was controlled by pressing the elastomer or deforming the droplet.
Completely Closed Optical Shell Using Total Internal Reflection with Simple Composition
Authors: Kobayashi Tetsuro
Published: September 2010

A simple completely closed optical shell is proposed. This shell consists of only a block made of a transparent material with a cave inside, although it is required that the inner and outer surfaces of the shell consist of specially arranged planes and that the refractive index of the material of the shell is larger than √4+2√2≈2.613…. No light ray from the inside of the shell can pass through the outside of the shell because the light ray always totally internally reflects at the outer surface of the shell. On the other hand, no light ray from outside can enter the cave through this transparent shell. It is considered that this shell functions as a very high-Q optical cavity and exists in various sizes from micrometers to submeters. The principle of light confinement in the shell is clarified by ray-tracing analysis.
Proton-Implanted Planar Waveguide in Gallium Lanthanum Sulphide Glass
Authors: Qiu Feng , Narusawa Tadashi
Published: September 2010

Owing to the remarkable properties of chalcogenide glasses, chalcogenide optical waveguides should play a significant role in the development of integrated optics. This work demonstrates that an optical waveguide can be obtained by a simple proton implantation in gallium lanthanum sulphide (GLS) glass. Two modes exist in the waveguide at a wavelength of 632.8 nm and the refractive index profile of the waveguide is reconstructed. The near-field pattern of the transmitted light is obtained, and the propagation loss is about 3.2 dB/cm for the present waveguide.
Stability Analysis of Particle Trapping in Time-Division Optical Tweezers by the Generalized Lorentz–Mie Theory
Authors: Yamamoto Johtaro , Iwai Toshiaki
Published: September 2010

Time-division multiplexing in the proposed holographic optical tweezers (HOT) has been used to quasi-simultaneously generate two different intensity patterns, a carrier beam spot and a beam array, by alternately feeding the corresponding hologram patterns to a spatial light modulator (SLM). Since the switching of the input holograms degrades the spatial stability of trapping a Brownian particle within the generated intensity spot area, it is necessary to numerically investigate the conditions in the time-division multiplexing for a particle to be stably trapped by a focused Gaussian beam. The Smoluchowski equation based on the generalized Lorentz–Mie theory (GLMT) model is evaluated numerically by an explicit method to estimate the relationship among particle size, switching rate, and focused laser beam power. Finally, the validity of the numerical analysis in this work is confirmed by experiments.
Dysprosium Nitride-Modified Sintered Nd–Fe–B Magnets with Increased Coercivity and Resistivity
Authors: Liu Qiongzhen , Zhang Lanting , Xu Fang , Dong Xianping , Wu Jiansheng , Komuro Matahiro
Published: September 2010

The magnetic properties, electrical resistivity and related microstructures of (Nd,Pr)14.5Dy1.2FebalAl0.8B6 magnets modified by DyN addition have been investigated. The coercivity of the magnets increases almost linearly as a function of DyN content without a considerable reduction in remanence. Similarly, the resistivity in the transversal orientation increases from 1.6 to about 2.0 µΩ m. N dissolves in the grain boundary Nd-rich phase, leading to the formation of an N-containing amorphous phase. This amorphous phase is found to enhance the electrical resistivity. Dy tends to diffuse into the matrix phase, enriched on the matrix side of the interface between the grain boundary phase and the matrix. The significant improvement of the coercivity is ascribed to the increased anisotropy of R2Fe14B by partial substitution of Dy for Nd.
Electric Properties of All Solid Ion-Transfer Device Fabricated with Transition Metal Cyanide Films
Authors: Shibata Takayuki , Moritomo Yutaka
Published: September 2010

Electric properties are systematically investigated for an all solid ion-transfer device made by various transition metal cyanide films, Na
x
Co[Fe(CN)6]0.90·2.9H2O (NCF90), Na
x
Co[Fe(CN)6]0.71·3.8H2O (NCF71), and Na
x
Ni[Fe(CN)6]0.68·5.1H2O (NNF68). On the basis of scanning electron microscope (SEM) analysis and X-ray diffraction analysis, we concluded that the NCF90 film consists of weakly (111)-oriented large rod like crystals, while the NCF71 film consists of (111)-oriented fine needle like crystals grown perpendicular to the substrate. On the other hand, granular particles are piled up in the NNF68 film. We found that the devices made by the NCF90 and NCF71 films show rapid ion transfer (response time τ= 1 s at 1 V), while the device made by the NNF68 film shows a slow response (τ= 6 s at 1 V). These results indicate that crystalline film is indispensable for rapid device response.
Random Telegraph Signal-Like Fluctuation Created by Fowler–Nordheim Stress in Gate Induced Drain Leakage Current of the Saddle Type Dynamic Random Access Memory Cell Transistor
Authors: Kim Heesang , Oh Byoungchan , Kim Kyungdo , Cha Seon-Yong , Jeong Jae-Goan , Hong Sung-Joo , Lee Jong-Ho , Park Byung-Gook , Shin Hyungcheol
Published: September 2010

We generated traps inside gate oxide in gate–drain overlap region of recess channel type dynamic random access memory (DRAM) cell transistor through Fowler–Nordheim (FN) stress, and observed gate induced drain leakage (GIDL) current both in time domain and in frequency domain. It was found that the trap inside gate oxide could generate random telegraph signal (RTS)-like fluctuation in GIDL current. The characteristics of that fluctuation were similar to those of RTS-like fluctuation in GIDL current observed in the non-stressed device. This result shows the possibility that the trap causing variable retention time (VRT) in DRAM data retention time can be located inside gate oxide like channel RTS of metal–oxide–semiconductor field-effect transistors (MOSFETs).
Improved Performance of Phase Change Memory Cell with Strontium Titanate and Barium Titanate Buffer Layer
Authors: Shang Fei , Zhai Jiwei , Song Sannian , Song Zhitang , Wang Changzhou
Published: September 2010

T-shape phase change memory (PCM) cells with SrTiO3(STO) or BaTiO3(BTO) buffer layer were fabricated and characterized. Compared to the conventional T-shape PCM cell, the reset voltages using BTO and STO as buffer layer with pulse width 50 ns were reduced by 28 and 38%, respectively. According to the result of the thermal resistance calculation, the overall thermal resistance of PCM cell increases remarkably by inserting BTO (STO) layer, which can efficiently reduce the dissipated power, resulting in the reduced reset voltage. Combined with the resistance–voltage characteristics of the PCM cell, the current–voltage characteristics of BTO and STO thin films indicate that BTO thin film is more suitable than STO thin film as a buffer layer. The theoretical thermal simulation for reset process is applied to understand the effect of buffer layer on improving the performance of the PCM cell.
Optical Properties of Silicon Nanowires Fabricated by Electroless Silver Deposition
Authors: Toda Satoru , Oishi Tetsuji , Yoshioka Takuma , Okuno Tsuyoshi
Published: September 2010

Vertically aligned silicon nanowires are fabricated on silicon substrates by electroless silver deposition, and their optical properties are investigated. The diameter of the nanowires ranges from 100 to 500 nm and their length ranges from 30 to 100 µm. Red photoluminescence appears at approximately 700 nm at room temperature. Its peak and intensity vary along the wire positions in Raman microscopy measurements. The photoluminescence intensity is high at the top of the wire. In this region, oxidation is enhanced and the Raman scattering spectra of the optical phonon mode tend to be broadened. The origin of the red photoluminescence is assumed to be defect states located at the interface between the core of the silicon nanowires and the surrounding silicon oxide.
Piezoelectric Pump Using a Cymbal Transducer
Authors: Gosain Rohan , Gurdal Erkan Ahmet , Zhuang Yuan , Park Seung-Ho , Lee Sung-Gap , Uchino Kenji
Published: September 2010

This paper treats an innovative piezoelectric pump based on one of the piezoelectric actuators, the “cymbal”. We describe the design, fabrication process, pumping principle and performance analysis of a miniaturized, ultrasonic, valve less pump. The cymbal actuator has been shown to have larger displacement and generative force than the bimorph actuators. The key is much higher underwater pressure induced by the cymbal in comparison with the bimorph. We used a double-layered cymbal with the advantage that it can behave both, as an “in-phase” extensional or an “out-of-phase” bending actuator. Our setup promises a hassle-free, internal system which offers considerably smaller size and weight, thereby facilitating the current trend of size reduction in the electronics industry. In addition, ease of fabrication make this device an attractive candidate for large scale production/industrial use. Taking inspiration from current and past trends we tried to balance the trade-off between efficient performance and device size. Therefore, a key feature of this pump is performance with respect to size (volume less than 1.5 cm3). The pump was able to generate a maximum back pressure greater than 5.3 kPa and an approximate maximum flow rate of 10 ml/min.
Molecular Dynamics Evaluation of Thermal Transport in Naked and Oxide-Coated Silicon Nanowires
Authors: Saegusa Takumi , Eriguchi Koji , Ono Kouichi , Ohta Hiroaki
Published: September 2010

The thermal conductivities (κ) of Si nanowires (SiNWs) with naked and sub-nm-oxidized surfaces have been evaluated by nonequilibrium classical molecular dynamics simulations. For the naked SiNWs, the dependence of κ on the cross-sectional area qualitatively agreed with previous Monte Carlo simulations and experiments. It was confirmed that κ was not sensitive to cross-sectional shape or crystalline orientation. The κ of the SiO
x
-coated SiNWs was decreased compared with that of the naked SiNWs when both types of NW had the same crosssection. However, the κ corresponding to the core part of Si (including the interfacial layer between the Si core and surface SiO
x
) was equivalent to the κ of the naked SiNWs. The presence of a surface oxide does not modulate the internal thermal conduction of the SiNWs.
Numerical Simulations of Accommodation Coefficient Effects at the Head-Disk Interface
Authors: Zhou Weidong , Liu Bo , Yu Shengkai , Hua Wei
Published: September 2010

In this article, we use our proposed heat transfer model, which can be well validated by using the direct simulation Monte Carlo (DSMC) method, to investigate the thermal accommodation coefficient (TAC) effects on the heat conduction in rarefied gas filled head-disk interface (HDI). We also employ some numerical techniques to analyze the slider's thermal and flying performances for arbitrary surface accommodation coefficients. The simulation studies show that as the TAC decreases, the heat transfer at the HDI is reduced, which increases thermal protrusion on the slider and lowers slider's flying height (FH) accordingly. It is also found that tangential momentum accommodation coefficient (TMAC) affects slider's FH more significantly than the TAC. The dependency of TMAC and TAC on the temperature is also discussed based on molecular trapping-desorption theory and a variety of TAC and TMAC values are suggested to improve the accuracy of predicting heat transfer and air bearing at the HDI of hard disk drives.
Time-Resolved X-ray Diffraction Measurements of High-Density InAs Quantum Dots on Sb/GaAs Layers and the Suppression of Coalescence by Sb-Irradiated Growth Interruption
Authors: Kakuda Naoki , Kaizu Toshiyuki , Takahasi Masamitu , Fujikawa Seiji , Yamaguchi Koichi
Published: September 2010

Self-assembly of high-density InAs quantum dots (QDs) on Sb-irradiated GaAs buffer layers was observed in-situ by a time-resolved X-ray diffraction (XRD) technique using a combination of XRD and molecular beam epitaxy. Evolution of dot height and lattice constant was analyzed during InAs QD growth and subsequent growth interruption (GI), and as a result, dislocated giant dots due to coalescence and coherent dots were separately evaluated. An Sb-irradiated GI (Sb-GI) method to be applied after InAs growth was attempted for the suppression of coalescence. Using this method, the XRD intensity of giant dots decreased, and the photoluminescence intensity of InAs QDs was enhanced. High-density InAs QDs without giant dots were produced by using the combination of the QD growth on the Sb-irradiated GaAs buffer layers and the Sb-GI.
Effects of Re-baking and Substrate Temperature on Optical Properties and Residual Stress of Ion-Assisted Deposition TiO2 Thin Film
Authors: Chen Hsi-Chao , Lee Kun-Hsien , Jaing Cheng-Chung , Lee Cheng-Chung
Published: September 2010

Titanium oxide (TiO2) thin films were prepared by ion-assisted deposition (IAD) on glass substrates at various substrate temperatures. These films were re-baked and at the temperature of re-crystallization. The effects of the stability of the films on their optical properties, residual stress and surface roughness were studied. The evolution of oxidation and the cause of the variation in the optical properties and residual stress during baking and re-baking were discussed. However, the optical constants, residual stress and surface roughness varied less in re-baking than in baking. During both baking and re-baking, at substrate temperatures of 150 °C, the extinction coefficients, residual stress and surface roughness fluctuated more than at substrate temperatures of 200 and 250 °C. These results all reveal that TiO2 films were more stable after re-baking than after baking, and it was especially useful for the IAD films deposited at substrate temperature of 150 °C.
Leakage Current Characteristics of Lead-Free K0.5Na0.5NbO3 Ferroelectric Thin Films with (K,Na) Excess and Li Substitution
Authors: Kim Jin Soo , Lee Sun Young , Ahn Chang Won , Hwang Hak In , Lee Hai Joon , Bae Se Hwan , Kim Ill Won
Published: September 2010

K0.5Na0.5NbO3 thin films with (K,Na) excess and LiNbO3 substitution were fabricated on a Pt substrate by a chemical solution deposition method. The K0.5Na0.5NbO3 thin films with (K,Na) 10 mol % excess and LiNbO3 5 mol % substitution showed a saturated ferroelectric polarization–electric field (P–E) hysteresis loop and the estimated remanent polarization (P
r) and coercive field (E
c) were 8.6 µC/cm2 and 40 kV/cm at 280 kV/cm, respectively. Compared to pure K0.5Na0.5NbO3 thin films, the ferroelectric polarization of the thin film was improved and leakage current densities were decreased. Moreover, the ferroelectric polarization and leakage current characteristics are stable for higher applied electric fields and elevated temperatures. The conduction behaviours of these films were analyzed by Schottky and Poole–Frenkel emission.
Hydrocarbon Redeposition on Plasma Facing Walls Intersecting Magnetic Field at Shallow Angles
Authors: Ohya Kaoru , Inai Kensuke
Published: September 2010

In present nuclear fusion devices, hydrocarbons resulting from the chemical sputtering of carbon-based walls redeposit on other areas of the wall after transport in plasmas, forming hydrogen-rich carbon layers. A particle-in-cell calculation of a sheath region between the plasma and the wall is incorporated into the transport simulation of methane (CH4) and the fragments in the plasma. The effect of the magnetic field intersecting the wall surface at shallow angles on the redeposition characteristics is studied, taking the reflection and sticking on the wall into account. The redeposition rate is rather slowly increased with increasing angle between the magnetic field line and the surface normal, whereas it strongly depends on the plasma temperature and the sticking probability,S, of hydrocarbons (CHx) returning to the surface. By assumingS= 1, the redeposition of large molecular ions (CH3+and CH4+) is suppressed at shallow angles (θ> 85°), whereas the redeposition of atomic C ions is enhanced. For zero sticking (S= 0), the redeposition is dominated by C ions at high temperature, whereas at low temperature, it is dominated by neutral C atoms.