bluuebunny/crossref_metadata_2025 huggingface dataset:
A new inhibitory pathway in the jellyfishPolyorchis penicillatus
Authors: Mackie G.O. , Meech R.W. , Spencer A.N.
Published: February 2012

Contact of food with the manubrial lips in the genus Polyorchis A. Agassiz, 1862 evokes trains of electrical impulses (E potentials) that propagate to the margin. E potentials are also produced by food stimuli at the margin and tentacle bases. E potentials are shown to be associated with inhibitory postsynaptic potentials (ipsps) in the swimming motor neurons and contribute to the arrest of swimming during feeding. The conduction pathway for E potentials is a nerve plexus located in the endodermal walls of the stomach and radial and ring canals. We have explored the conducting properties of the system; the conduction velocity varies with stimulus frequency but is about 15 cm/s when stimuli are more than 50 s apart. Neurites belonging to the E system run around the margin adjacent to the inner nerve ring, where the swimming pacemaker neurons are located. We suggest that they may make inhibitory synapses on to the swimming motor neurons, but this has yet to be demonstrated anatomically. The reversal potential for ipsps, recorded intracellularly with potassium acetate micropipettes, was estimated to be about –69 mV. Swimming inhibition mediated by this endodermal pathway is distinct from that observed during protective “crumpling” behaviour and that associated with contractions of the radial muscles seen during feeding, though it may accompany the latter.
Prolonged life span among endemicGasterosteuspopulations
Authors: Gambling S.J. , Reimchen T.E.
Published: February 2012

Throughout their circumboreal coastal distribution, the threespine stickleback ( Gasterosteus aculeatus L., 1758) typically reproduce at 1 or 2 years of age (second or third summer) and die during the year of the reproductive cycle. Extending from a previous study on the Haida Gwaii archipelago, western Canada, that identified an exceptionally long life span (8 years) in a population of large-bodied threespine stickleback, we use pelvic spine annuli to examine age of the five largest adult stickleback of 12 additional populations comprising five populations with average-sized adults (45–60 mm standard length (SL)) and seven populations with large-bodied adult stickleback (>75 mm SL). Each of the small-bodied populations had a maximum age of 1 or 2 years typical for the taxon. Among the large-bodied populations, which also reached adult size in the 2nd year, adult stickleback in the populations ranged from 3 to 6 years, indicating extended longevity. Low productivity habitats and refuge against gape-limited piscivores, each of which theoretically predicts reduced rate of senescence, are associated with the greatest longevity among these populations. These data combined with the recent full genome sequence for stickleback provide opportunities for locating genetic markers for extended longevity.
ONE-LOOP CORRECTION TO ENERGY OF SPINNING STRINGS IN AdS5×T1, 1
Authors: KIM HYOJOONG , KIM NAKWOO , LEE JUNG HUN
Published: February 2012

We consider circular spinning string solutions in AdS5×T1, 1 and calculate the quantum corrections to the energy at one-loop on worldsheet. The fluctuations are given as a set of harmonic oscillators and we calculate their normal mode frequency in closed form. The sum of frequency is equal to the one-loop string energy, which through AdS/CFT correspondence corresponds to the leading order correction of the conformal dimension for long operators in Klebanov–Witten conifold gauge field theory.
DIRECT COUNTING ANALYSIS ON NETWORK GENERATED BY DISCRETE DYNAMICS
Authors: LIOU SHU-HAO , CHEN CHIA-CHU
Published: February 2012

A detail study on the in-degree distribution (ID) of cellular automata is obtained by exact enumeration. The results indicate large deviation from multi-scaling and classification according to various IDs are discussed. We further augment the transfer matrix such that the distributions for more complicated rules are obtained. Dependence of ID on the lattice size have also been found for some rules including R50 and R77.
MAGNETIC PROPERTIES OF SEMICONDUCTOR QUANTUM DOTS WITH GAUSSIAN CONFINEMENT
Authors: BOYACIOGLU BAHADIR , CHATTERJEE ASHOK
Published: February 2012

The magnetic properties such as magnetization and magnetic susceptibility are calculated for semiconductor quantum dots with Gaussian confinement. It is shown that the magnetization and magnetic susceptibility effects are quite significant for quantum dots with deep confining potential well and the parabolic potential is only a poor approximation of the Gaussian confinement.
MULTIFRACTALS, GENERALIZED SCALE INVARIANCE AND COMPLEXITY IN GEOPHYSICS
Authors: SCHERTZER DANIEL , LOVEJOY SHAUN
Published: February 2012

The complexity of geophysics has been extremely stimulating for developing concepts and techniques to analyze, understand and simulate it. This is particularly true for multifractals and Generalized Scale Invariance. We review the fundamentals, introduced with the help of pedagogical examples, then their abstract generalization is considered. This includes the characterization of multifractals, cascade models, their universality classes, extremes, as well as the necessity to broadly generalize the notion of scale to deal with anisotropy, which is rather ubiquitous in geophysics.
SYMBOLIC DYNAMICS, COARSE GRAINING AND THE MONITORING OF COMPLEX SYSTEMS
Authors: BASIOS VASILEIOS , MAC KERNAN DÓNAL
Published: February 2012

Coarse graining techniques and their associated symbolic dynamics are reviewed with a focus on probabilistic aspects of complex dynamical systems. The probabilistic approach initiated by Nicolis and coworkers has been elaborated. One of the major issues when dealing with the dynamics of complex nonlinear systems, the fact that the inherent time-scales of the unfolding phenomena are not well separated, is brought into focus. Recent results related to this interdependence, which is one of the most characteristic aspects of complexity and a major challenge in prediction, error estimates and monitoring of nonlinear complex systems, are discussed.
CLIMATE THEORY VERSUS A THEORY FOR CLIMATE
Authors: ESSEX CHRISTOPHER
Published: February 2012

While famous theoretical work has been done historically on climate, no precise testable physical theory for climate has ever emerged. That is because, among other reasons, the definition of the objective is imprecise. The most common definition of climate as averaged weather, is more cliché than definition. Average over what? Average in what way? Is there a function relating resulting averages to each other, or do the averages satisfy differential equations? There is not one but many divergent approaches to defining climate in terms of averages, which seem to coexist without mutual competition. The three primary approaches employ time averages, field averages, and model solution ensemble averages, respectively. Each is problematic in its own way. While it is easy to produce an average, finding equations that can stand on their own in terms of averaged quantities only is not straightforward. But such equations are the ultimate aim of a search for a theory of climate, examining the questions of what averaging rule over what physical quantities help point to what an actual theory for climate ought to be like. This paper discusses averaging and closure in other fields, such as kinetic theory and turbulence, and how they are relevant to a theory of climate. It suggests how we might learn from them, while identifying how these issues need more exploration in terms of the climate problem.
AN EQUATION OF STATE FOR LAND SURFACE CLIMATES
Authors: FRAEDRICH KLAUS , SIELMANN FRANK
Published: February 2012

A biased coinflip Ansatz provides a stochastic regional scale surface climate model of minimum complexity, which represents physical and stochastic properties of the rainfall–runoff chain. The solution yields the Schreiber–Budyko relation as an equation of state describing land surface vegetation, river runoff and lake areas in terms of physical flux ratios, which are associated with three thresholds. Validation of consistency and predictability within a Global Climate Model (GCM) environment demonstrates the stochastic rainfall–runoff chain to be a viable surrogate model for regional climate state averages and variabilites. A terminal (closed) lake area ratio is introduced as a new climate state parameter, which quantifies lake overflow as a threshold in separating water from energy limited climate regimes. A climate change analysis based on the IPCC A1B scenario is included for completeness.
MULTIWALLED CARBON NANOTUBES BASED NANOCOMPOSITES FOR SUPERCAPACITORS: A REVIEW OF ELECTRODE MATERIALS
Authors: KIAMAHALLEH MEISAM VALIZADEH , ZEIN SHARIF HUSSEIN SHARIF , NAJAFPOUR GHASEM , SATA SUHAIRI ABD , BUNIRAN SURANI
Published: February 2012

Electrode materials are the most important factors to verify the properties of the electrochemical supercapacitor. In this paper, the storage principles and characteristics of electrode materials, including carbon-based materials, transition metal oxides and conducting polymers for supercapacitors are depicted in detail. Other factors such as electrode separator and electrolyte are briefly investigated. Recently, several works are conducted on application of multiwalled carbon nanotubes (MWCNTs) and MWCNTs-based electrode materials for supercapacitors. MWCNTs serve in experimental supercapacitor electrode materials result in specific capacitance (SC) value as high as 135 Fg-1. Addition of pseudocapacitive materials such as transition metal oxides and conducting polymers in the MWCNTs results in electrochemical performance improvement (higher capacitance and conductivity). The nanocomposites of MWCNTs and pseudocapacitive materials are the most promising electrode materials for supercapacitors because of their good electrical conductivity, low cost and high mass density.
CHAOTIC RESPONSE ANALYSIS OF SINGLE-WALLED CARBON NANOTUBE DUE TO SURFACE DEVIATIONS
Authors: JOSHI ANAND Y. , SHARMA SATISH C. , HARSHA S. P.
Published: February 2012

Nonlinear vibrational behavior of a single-walled carbon nanotube based mass sensors is considered. The modeling involves stretching of the mid plane and damping. The equation of motion involves two nonlinear terms due to the curved geometry and the stretching of the central plane due to the bridged boundary conditions. The manifestation of instability and chaos in the dynamic response is observed. The regions of periodic, sub-harmonic and chaotic behavior are clearly seen to be dependent on added mass and the surface deviations. Poincaré maps and frequency spectra are used to explicate and demonstrate the miscellany of the system behavior.
Enhancement in the Light Output Power of GaN-Based Light-Emitting Diodes with Nanotextured Indium Tin Oxide Layer Using Self-Assembled Cesium Chloride Nanospheres
Authors: Zhang Yiyun , Li Jing , Wei Tongbo , Liu Jing , Yi Xiaoyan , Wang Guohong , Yi Futing
Published: February 2012

In this study, enhanced light output power in GaN-based light-emitting diodes (LEDs) with a nanotextured indium tin oxide (ITO) transparent conductive layer was observed. Wafer-scale self-assembled cesium chloride nanospheres were formed on the ITO transparent conductive layer and served as the mask in a dry etching process. After the inductively coupled plasma (ICP) etching process, nanoscale islands were fabricated on the ITO layer. Compared with LEDs with a planar ITO layer, the light output power of LEDs with a nanotextured ITO layer was improved by 23.4%. Optoelectronic measurement showed that the performance of the fabricated LEDs was greatly enhanced.
Integrated AlGaAs Quantum-Well Ridge-Structure Two-Wavelength Distributed Bragg Reflector Laser for Terahertz Wave Generation
Authors: Uemukai Masahiro , Ishida Hidenao , Ito Akira , Suhara Toshiaki , Kitajima Hidenori , Watanabe Akiyoshi , Kan Hirofumi
Published: February 2012

An integrated two-wavelength distributed Bragg reflector (DBR) laser consisting of two DBR lasers and a Y-branch waveguide amplifier was designed and fabricated. The optical waves from the two DBR lasers are combined into a single output channel of the Y-branch waveguide amplifier and emitted from the output facet. Laser performances of the same output level of ∼10 mW and a wavelength difference of 1.0–3.7 nm (0.47–1.8 THz beat frequency) with a side-mode suppression ratio of 30 dB were obtained. Coherent THz wave generation was also demonstrated by photomixing of the integrated two-wavelength laser output.
Electro-Thermal Beam Steering Using Bragg Reflector Waveguide Amplifier
Authors: Gu Xiaodong , Shimada Toshikazu , Fuchida Ayumi , Matsutani Akihiro , Imamura Akihiro , Koyama Fumio
Published: February 2012

We demonstrate the electro-thermal beam steering taking advantage of the large angular dispersion of a Bragg Reflector waveguide amplifier. It is realized by changing the waveguide refractive index with injection current in the amplifier. Both theoretical calculations and experimental demonstration are presented. Output light rotates over 6° with an injection current of 400 mA. The divergence angle is smaller than 1°. The result reveals a possibility of electro-thermal tuning in our proposed beam steering device.
Optical Properties of ZnO Soccer-Ball Structures Grown by Vapor Phase Transport
Authors: Nam Giwoong , Lee Sang-heon , Kim Soaram , Kim Min Su , Kim Do Yeob , Yim Kwang Gug , Lee Dong-Yul , Kim Jin Soo , Kim Jong Su , Son Jeong-Sik , Kim Sung-O , Jung Jae Hak , Leem Jae-Young
Published: February 2012

ZnO soccer balls were grown on an Au-catalyzed Si(100) substrate by vapor phase transport (VPT) with a mixture of zinc oxide and graphite powders. Temperature-dependent PL was carried out to investigate the mechanism governing the quenching behavior of the PL spectra. From the PL spectra of the ZnO soccer balls at 10 K, several PL peaks were observed at 3.365, 3.318, 3.249, and 3.183 eV corresponding to excitons bound to neutral donors (DoX), a donor–acceptor pair (DAP), first-order longitudinal optical phonon replica of donor–acceptor pair (DAP-1LO), and DAP-2LO, respectively. The mixed system composed of the free exciton (FX) and DoX and the DAP radiative lifetimes were estimated with a theoretical relation between the lifetime and the spectral width. The exciton radiative lifetimes were observed to increase linearly with temperature.
n-Type Nanocrystalline FeSi2/intrinsic Si/p-Type Si Heterojunction Photodiodes Fabricated by Facing-Target Direct-Current Sputtering
Authors: Promros Nathaporn , Yamashita Kyohei , Li Chen , Kawai Kenji , Shaban Mahmoud , Okajima Toshihiro , Yoshitake Tsuyoshi
Published: February 2012

n-Type nanocrystalline (NC) FeSi2/intrinsic (i) Si/p-type Si heterojunctions, which were prepared by facing-target direct current sputtering, were evaluated as near-infrared photodiodes, and the effects of thin i-Si layer insertion on diode performance were studied. Their junction capacitance and reverse leakage current were clearly reduced compared with those of n-type NC-FeSi2/p-type Si heterojunctions. The capacitance–voltage curve implied that the effects of interface states is relatively suppressed by i-Si insertion. The near-infrared light detection performance was investigated using a 1.33 µm laser in the temperature range of 77–300 K. The detectivities at 300 and 77 K were 1.9 ×108 and 3.0 ×1011 cm Hz1/2 W-1, respectively, at a negative bias of -5 V, which were markedly improved compared with that of p–n heterojunctions. This might be because the formation of interface states that act as trap centers for photocarriers is suppressed.
Temperature Dependence of Trap Density Distribution in Poly(3-hexylthiophene) and 1-(3-Methoxycarbonyl)-propyl-1-phenyl-(6,6)C61 Based Blending Films under Illumination
Authors: Lou Yanhui , Wang Zhaokui , Naka Shigeki , Okada Hiroyuki
Published: February 2012

Measurements of the current density–voltage (J–V) characteristics of a poly(3-hexylthiophene) (P3HT) and 1-(3-methoxycarbonyl)-propyl-1-phenyl-(6,6)C61 (PCBM)-based electron-dominated device as functions of temperature were carried out. A transport transition from three-dimensional variable range hopping (VRH) to space-charge-limited current (SCLC) with an exponential distribution of traps (filled and unfilled) was observed. The bulk trap density, about 1018 cm-3, of the P3HT:PCBM blend film was evaluated by the differential method. A shift to the lowest unoccupied molecular orbital (LUMO) state of PCBM for trap density distribution was observed owing to the temperature dependence of the Fermi level of PCBM materials. It is supposed that the Fermi level of PCBM materials is strongly temperature-dependent similarly to that of amorphous silicon semiconductors.
Evidence of Nitrogen Reorganization in GaAsSbN Alloys
Authors: Hsu Hung-Pin , Lin Yan-Ting , Lin Hao-Hsiung
Published: February 2012

In this report, the effects of thermal annealing properties on dilute GaAsSbN alloys grown on GaAs substrates using gas-source molecular beam epitaxy were investigated by photoreflectance (PR) and Raman spectroscopy. The PR spectra of the annealed GaAsSbN showed the up shift of dominant near band edge transition as compared to the as-grown samples. The observed shift can be attributed to the chemical change of the second-nearest-neighbor atoms to the N atoms. Raman spectroscopy analysis yielded further insight on the atomic configuration of post annealed GaAsSbN. The plausible physical mechanisms induced by thermal reorganization in GaAsSbN alloys were presented and discussed.
Positive Gain Observation in a Nd-Doped Active Fiber Pumped by Low-Concentrated Solar-Like Xenon Lamp
Authors: Endo Masamori , Bisson Jean-François
Published: February 2012

Neodymium-doped silica glass fiber is pumped by a Xe arc lamp as a simulated solar light. The fiber is immersed in rhodamine 6G solution to enhance the photon flux at the 588 nm absorption band of the Nd3+. The chamber that contains the active fiber and dye solution is made of a pair of reflectors. The bottom reflector is highly reflective over the entire visible spectrum, while the top reflector is a short-pass dichroic mirror whose cutoff wavelength is set at 580 nm. As a result, the dye fluorescence of the absorption band is confined by the multiple reflections, like a “greenhouse effect”. The expected confinement factor as a function of the angular-dependent reflectivity of the reflectors is discussed. The highest gain observed is 1.0 ×10-2 m-1 when the lamp light intensity is 2.7 W/cm2.
Subharmonic Synchronization of Picosecond Yb Fiber Laser to Picosecond Ti:Sapphire Laser for Stimulated Raman Scattering Microscopy
Authors: Umemura Wataru , Fujita Kenta , Ozeki Yasuyuki , Goto Ken , Sumimura Kazuhiko , Nishizawa Norihiko , Fukui Kiichi , Itoh Kazuyoshi
Published: February 2012

We demonstrate a subharmonically synchronized picosecond laser system and its application to stimulated Raman scattering (SRS) microscopy for label-free biological imaging with high sensitivity and high spectral resolution. Experimentally, 5.5-ps Yb fiber laser pulses at a repetition rate of 38 MHz were successfully synchronized to 4.8-ps Ti:Sapphire laser pulses at a repetition rate of 76 MHz, by using a two-photon detector, an intracavity electro-optic modulator, and a piezoelectric transducer. The temporal jitter was measured to be 120 fs. These pulses were applied to SRS microscopy. We confirmed the shot-noise-limited sensitivity, and succeeded in SRS spectroscopy of a polymer bead as well as three-dimensional SRS imaging of a HeLa cell.
Hot-Carrier Effects in Short Channel (L = 1.5 µm) p-Type Polycrystalline Silicon Thin-Film Transistors
Authors: Choi Sung-Hwan , Mo Yeon-Gon , Kim Hye-Dong , Han Min-Koo
Published: February 2012

We have investigated the reliability of short-channel (L = 1.5 µm) p-type excimer-laser-annealed (ELA) polycrystalline silicon (poly-Si) TFTs under hot-carrier related static bias stress. The threshold voltage (ΔV
TH = 0.59 V) of short-channel TFTs (L = 1.5 µm) was significantly more shifted to the positive direction than that (ΔV
TH = 0.02 V) of long-channel TFTs (L = 7 µm) under the same stress condition for 100 s. This positive shift of threshold voltage may be attributed to electron trapping at the interface between the poly-Si film and the gate oxide layer. In addition, we have extracted the length of the drain extension from an equation of the pseudo-lightly doped drain (LDD) model to verify the existence of free hole charges induced near the drain junction. The transfer characteristics of the normal and drain-source swapped modes as well as the capacitance–voltage (C–V) characteristics with variation in channel length after the bias stress indicate that the electron trapping at the gate insulator/channel interface mainly occurred near the drain junction region. Furthermore, the threshold voltage of the short-channel ELA poly-Si TFTs with L = 1.5 µm was largely increased as the stress temperature was increased from room temperature to 100 °C, which indicates that the impact ionization occurs more at higher temperature.
High-Performance Semitransparent Bulk-Heterojunction Organic Photovoltaics with Ag Interfacial Layer
Authors: Han Jeong In , Park Jun-Ki , Park Sung Kyu
Published: February 2012

Semitransparent bulk-heterojunction organic photovoltaics with power conversion efficiency (PCE) of 1.63±0.39% was achieved by using poly(3-hexylthiophene) (P3HT)/phenyl-C61-butyric acid methyl ester (PCBM) active layer and Ag/Ca/Ag transparent cathode. Insertion of a thin Ag interfacial layer (1 nm) between the P3HT/PCBM active layer and Ca/Ag transparent cathode dramatically improved the PCE from 0.83±0.33 to 1.63±0.39% as well as other photovoltaic properties such as fill factor, short-circuit current, and series resistance. In this experiment, it is considered that the improved device performance is possibly due to improved contact property by the Ag interfacial layer at the active/cathode interface.
Effect of Graded AlxGa1-xN Layers on the Properties of GaN Grown on Patterned Si Substrates
Authors: Hsiao Yu-Lin , Lu Lung-Chi , Wu Chia-Hsun , Chang Edward Yi , Kuo Chien-I , Maa Jer-Shen , Lin Kung-Liang , Luong Tien-Tung , Huang Wei-Ching , Chang Chia-Hua , Dee Chang Fu , Majlis Burhanuddin Yeop
Published: February 2012

2.2-µm-thick crack-free GaN films were grown on patterned Si substrates. The crack-free GaN films were obtained by patterning Si substrate and optimizing the graded Al
x
Ga1-x
N layers. With the increase of the graded Al
x
Ga1-x
N layer thickness, the GaN crystal quality improved as judged from the X-ray diffraction data. By applying multi-Al
x
Ga1-x
N layers on the patterned Si substrate, a 31% reduction of tensile stress for the GaN film was obtained as measured by micro-Raman. For the AlGaN/GaN high electron mobility transistor grown on 1×1 cm2 larger patterns, the device exhibits maximum drain current density of 776 mA/mm and maximum transconductance of 101 mS/mm.
Cold Neutron Focusing with a Wolter Type-I Mirror
Authors: Aoki Sadao , Yamamoto Tsuyoshi , Furukawa Jun
Published: February 2012

A cold neutron beam from a research reactor was focused using a Wolter type-I mirror which was originally designed for X-ray imaging. The optical system was installed at JRR-3 of Japan Atomic Energy Agency (JAEA). Focused neutron images were taken at wavelengths of 0.6 nm to about 1 nm and they were detected by an imaging plate. The spatial resolution obtained at the focal plane was about 100 µm, which was limited mainly by the pixel size of the imaging plate.
Study of the Removal of Ion-Implanted Resists Using Wet Ozone
Authors: Goto Yousuke , Angata Yukihiro , Igarashi Masanori , Yamamoto Masashi , Nobuta Takuya , Iida Takayuki , Kono Akihiko , Horibe Hideo
Published: February 2012

We have investigated the removal of novolac resists into which B and P ions had been implanted with a dose of 5×1014 atoms/cm2 at acceleration energies of 10, 70, and 150 keV (ion-implanted resists), using wet ozone. Also, we confirmed the presence of the surface hardened layer of ion-implanted resists by cross-sectional observation using scanning electron microscopy (SEM), the stripping of the hardened layer using chemicals, and the measurement of the plastic-deformation hardness of the resists by nanoindentation. The removal rate for a resist using wet ozone decreased with increasing acceleration energy because the hardness of the resist increased with increasing acceleration energy. Moreover, we clarified by time-of-flight secondary ion mass spectrometry (TOF-SIMS), that the ion intensity of C10H- (m/z 121.01) for the hydrocarbon component, which has the unsaturated bonds as a component of the surface hardened layer increased with increasing acceleration energy. Cresol novolac resin was destroyed and carbonized by ion implantation. Therefore, the removal of ion-implanted resists became difficult with increasing acceleration energy.
Quantum Chemical Investigation of Si Chemical Dry Etching by Flowing NF3into N2Downflow Plasma
Authors: Hayashi Toshio , Ishikawa Kenji , Sekine Makoto , Hori Masaru , Kono Akihiro , Suu Koukou
Published: February 2012

A quantum chemical investigation of the chemical dry etching of N2downflow plasma and NF3flow into the downflow area was carried out by the B3LYP/6-31+G(d) method. The results provide a reasonable interpretation of how the chemical dry etching of Si takes place. Experimentally, it was reported that single-crystal silicon was etched in the N2downflow plasma with NF3flow and the etch rate depended on the etching conditions, and it had been deduced that the etchant was F atoms produced by the reaction of N*+ NF3. It was found through our calculations that there were three reaction routes of NF3proceeding F production in the initial reaction step, with N(2Do) and N2(A3Σu+) and by electron attachment, and it is thought that the most probable F production reaction in the downflow area is N(2Do) + NF3→N=NF2+ F and the next probable reaction is N2(A3Σu+) + NF3(3E)→N2(1Σg+) + NF2+F.
High-Precision Quadrupole Correction Lens for Ion-Beam Focusing: Design and Test of Multistage Self-Aligned Quadrupole Correction-Lens System
Authors: Okayama Shigeo , Sugiyama Yasuhiko
Published: February 2012

A multistage self-aligned quadrupole correction lens, which consists of two lens casings, is developed. Each lens-casing cylinder consists of three quadrupole and two aperture electrodes. All lens components in lens-casing cylinders are fabricated to achieve an electrode alignment accuracy better than 1 µm. Azimuth errors between entrance and exit lens-casing cylinders can be corrected using the rotary flange fastened to the entrance lens-casing cylinder. The correction-lens system is installed as the probe-forming objective lens in place of the rotationally symmetrical objective lens of the focused ion-beam system. Simulation results show that a four-stage quadrupole correction lens is useful as a correctable probe-forming objective lens because all aperture aberration coefficients can be effectively corrected under the condition of relatively low chromatic aberration. Probe-forming properties and beam shape affected by aperture aberrations of the four-stage quadrupole correction-lens system are observed by scanning ion microscope images.
Excess Carrier Lifetime in p-Type 4H-SiC Epilayers with and without Low-Energy Electron Irradiation
Authors: Kato Masashi , Matsushita Yoshinori , Ichimura Masaya , Hatayama Tomoaki , Ohshima Takeshi
Published: February 2012

We measured excess carrier lifetimes in as-grown and low-energy electron-irradiated p-type 4H-SiC epitaxial layers by the microwave photoconductivity decay method. The carrier lifetime increases with the excitation density in the epilayers. This dependence suggests that the dominant recombination center in the epilayers has a larger capture cross section for electrons than for holes. The low-energy electron irradiation reduces the carrier lifetime in the epilayers, and 1000 °C annealing increases the carrier lifetime in the electron-irradiated samples.
Intermittent Changes in the Number of Pulsating Bubbles under Ultrasound
Authors: Tuziuti Toru , Yasui Kyuichi
Published: February 2012

Intermittent changes in the number of pulsating bubbles under ultrasound are studied experimentally. The peak-to-trough intensity of the waveform of scattered light from cavitation bubbles corresponds to the number of pulsating bubbles. It is shown that the brightness of the illuminated bubbles in the captured images changes with the peak-to-trough scattered light intensity. It is remarkable that the number of bubbles may change while the formation of bubbles is almost maintained.
Biomarkers for oxidative stress in acute lung injury induced in rabbits submitted to different strategies of mechanical ventilation
Authors: Ronchi Carlos Fernando , Fioretto Jose Roberto , Ferreira Ana Lucia Anjos , Berchieri-Ronchi Carolina Bragiola , Correa Camila Renata , Kurokawa Cilmery Suemi , Carpi Mário Ferreira , Moraes Marcos Aurélio , Yeum Kyung-Jin
Published: February 2012

Oxidative damage has been said to play an important role in pulmonary injury, which is associated with the development and progression of acute respiratory distress syndrome (ARDS). We aimed to identify biomarkers to determine the oxidative stress in an animal model of acute lung injury (ALI) using two different strategies of mechanical ventilation. Rabbits were ventilated using either conventional mechanical ventilation (CMV) or high-frequency oscillatory ventilation (HFOV). Lung injury was induced by tracheal saline infusion (30 ml/kg, 38°C). In addition, five healthy rabbits were studied for oxidative stress. Isolated lymphocytes from peripheral blood and lung tissue samples were analyzed by alkaline single cell gel electrophoresis (comet assay) to determine DNA damage. Total antioxidant performance (TAP) assay was applied to measure overall antioxidant performance in plasma and lung tissue. HFOV rabbits had similar results to healthy animals, showing significantly higher antioxidant performance and lower DNA damage compared with CMV in lung tissue and plasma. Total antioxidant performance showed a significant positive correlation ( r = 0.58; P = 0.0006) in plasma and lung tissue. In addition, comet assay presented a significant positive correlation ( r = 0.66; P = 0.007) between cells recovered from target tissue and peripheral blood. Moreover, antioxidant performance was significantly and negatively correlated with DNA damage ( r = −0.50; P = 0.002) in lung tissue. This study indicates that both TAP and comet assay identify increased oxidative stress in CMV rabbits compared with HFOV. Antioxidant performance analyzed by TAP and oxidative DNA damage by comet assay, both in plasma, reflects oxidative stress in the target tissue, which warrants further studies in humans.
Bioactivity and Prognostic Significance of Growth Differentiation Factor GDF15 Secreted by Bone Marrow Mesenchymal Stem Cells in Multiple Myeloma
Authors: Corre Jill , Labat Elodie , Espagnolle Nicolas , Hébraud Benjamin , Avet-Loiseau Hervé , Roussel Murielle , Huynh Anne , Gadelorge Mélanie , Cordelier Pierre , Klein Bernard , Moreau Philippe , Facon Thierry , Fournié Jean-Jacques , Attal Michel , Bourin Philippe
Published: February 2012

Overexpression of growth differentiation factor 15 (GDF15) by bone marrow mesenchymal stem cells occurs widely in patients with multiple myeloma, but the pathophysiologic effects of GDF15 in this setting remain undefined. GDF15 has been described in numerous solid tumors but never in hematologic malignancies. In this study, we report that GDF15 significantly increases survival of stroma-dependent multiple myeloma cells including primary multiple myeloma cells. In particular, GDF15 conferred resistance to melphalan, bortezomib, and to a lesser extent, lenalidomide in both stroma-dependent and stroma-independent multiple myeloma cells. Akt-dependent signaling was critical to mediate the effects of GDF15, whereas Src and extracellular signal-regulated kinase 1/2 signaling pathways were not involved. Given these results, we tested the clinical significance of plasma concentrations of GDF15 (pGDF15) in 131 patients with multiple myeloma and found that it correlated with disease prognosis. Specifically, patients with high levels of pGDF15 had lower probabilities of event-free and overall survival 30 months after diagnosis than patients with low pGDF15 levels. Our findings suggest that tumor microenvironment-derived GDF15 is a key survival and chemoprotective factor for multiple myeloma cells, which is pathophysiologically linked to both initial parameters of the disease as well as patient survival. Cancer Res; 72(6); 1395–406. ©2012 AACR.
Molecular Pathways: Microsatellite Instability in Colorectal Cancer: Prognostic, Predictive, and Therapeutic Implications
Authors: Sinicrope Frank A. , Sargent Daniel J.
Published: February 2012

Microsatellite instability (MSI) is the molecular fingerprint of the deficient mismatch repair (MMR) system, which characterizes ∼15% of colorectal cancers. MSI develops as a result of germline mutations in MMR genes or, more commonly, from epigenetic silencing of MLH1 in sporadic tumors occurring in a background of methylation of CpG islands in gene promoter regions and in tumors that frequently show hotspot mutations in the BRAF oncogene. MSI tumors have distinct phenotypic features and have been consistently associated with a better stage-adjusted prognosis compared with microsatellite stable tumors. MSI negatively predicts response to 5-fluorouracil and may also determine responsiveness to other drugs used for treatment of colorectal cancers. Recent data have expanded the molecular heterogeneity of MSI tumors and may contribute to our understanding of differential chemosensitivity. The ability to identify deficient MMR has important implications for patient management, and it holds promise for therapeutic exploitation and for the development of novel therapeutics. Clin Cancer Res; 18(6); 1506–12. ©2012 AACR.
IL-6 and IL-13 in Induced Sputum of COPD and Asthma Patients: Correlation with Respiratory Tests
Authors: Grubek-Jaworska Hanna , Paplińska Magdalena , Hermanowicz-Salamon Joanna , Białek-Gosk Katarzyna , Dąbrowska Marta , Grabczak Elżbieta , Domagała-Kulawik Joanna , Stępień Julita , Chazan Ryszrda
Published: February 2012

Background: IL-6 is strongly implicated in the development of chronic obstructive pulmonary disease (COPD). IL-13 is the well-documented central mediator in allergic asthma. IL-6 is attributed to the proinflammatory activities in COPD as well as asthma. In COPD patients exacerbation is increased by serum IL-6. The association of IL-13 as well as IL-6 with the impaired respiratory function of asthma patients remains controversial. Objectives: The aim of this study was to compare the concentration of IL-6 and IL-13 in the induced sputum of asthma and COPD patients, and to assess the possible association of these cytokines with the impairment of lung function. Methods: Twenty-six subjects with COPD and 18 subjects with asthma were enrolled in this study. IL-6 and IL-13 levels were measured in induced sputum by ELISA and correlated with the results of respiratory tests. Results: The induced sputum of COPD patients had a significantly higher IL-6 level than the sputum of asthma subjects while no significant differences were found in the levels of IL-13. There was a statistically significant negative correlation between IL-6 level and FEV1 or FEV1/FVC in asthma patients (r = –0.59 and –0.54, respectively) and a negative correlation that did not reach statistical significance between IL-6 level and FEV1, FEV1% or FVC in COPD subjects (r = –0.30, –0.30 and –0.38, respectively). There was no relationship between concentrations of IL-13 and impaired respiratory function. Conclusions: Our results confirmed that IL-6, but not of IL-13, is associated with respiratory disorders in both asthma and COPD patients.
The Use of N-Terminal Pro-Brain Natriuretic Peptide to Evaluate Vascular Disease in Elderly Patients with Mental Illness
Authors: Nilsson Karin , Gustafson Lars , Hultberg Björn
Published: February 2012

Background: Serum N-terminal pro-brain natriuretic peptide (NT-proBNP) is regarded as a sensitive marker of cardiovascular disease. Vascular disease plays an important role in cognitive impairment. Method: In 447 elderly patients with mental illness, serum NT-proBNP level and the presence or absence of vascular disease according to the medical record were used to categorize patients in different subgroups of vascular disease. Results and Conclusion: Patients with vascular disease and elevated serum NT-proBNP level had a lower cognition level, shorter survival time, lower renal function and a higher percentage of pathological brain imaging than patients with vascular disease and normal NT-proBNP level. Thus, elevated serum NT-proBNP level might be helpful to detect patients who have a more severe cardiovascular disease.
Item Response Theory Reveals Variability of Functional Impairment within Clinical Dementia Rating Scale Stages
Authors: Miller Tyler M. , Balsis Steve , Lowe Deborah A. , Benge Jared F. , Doody Rachelle S.
Published: February 2012

Background/Aims:To investigate whether an item response theory (IRT) approach to measuring variations of dementia severity within Clinical Dementia Rating (CDR) stages is associated with activities of daily living (ADLs). Methods: IRT estimates of dementia severity within CDR stages in 1,181 patients were correlated with ADLs and analyzed. Results: IRT-determined dementia severity was significantly correlated with ADLs in three of four impaired dementia stages. Conclusion: An IRT approach shows considerable advantages over traditional scoring practices of the CDR not only because it increases precision in dementia measurement, but also because it enables one to discover more precise associations with functional outcomes such as ADLs.
Factors Associated with a Depressive Disorder in Alzheimer’s Disease Are Different from Those Found for Other Dementia Disorders
Authors: Barca Maria Lage , Engedal Knut , Laks Jerson , Selbaek Geir
Published: February 2012

Background: This study explores factors associated with depression in Alzheimer’s disease (AD) compared with mild cognitive impairment (MCI) and other dementia disorders. Method: In a prospective study we included 195 patients: 31 with MCI, 112 with AD and 52 with other dementias. Results: According to the ICD-10 and the DSM-IV criteria, 88 (44.1%) and 59 (30.3%), respectively, had a depressive disorder. An adjusted multiple regression analysis showed that previous depression (p < 0.05) was significantly associated with depression in AD patients. Severity of dementia (p < 0.05) was significantly associated with a depressive disorder in a group of patients with frontotemporal dementia, vascular dementia, or dementia due to Lewy Body disease or Parkinson’s disease. Conclusion: We found different factors associated with a depressive disorder in AD compared to those found for other dementia disorders.
Intravitreal Dexamethasone Implant in Patients with Persistent Diabetic Macular Edema
Authors: Zucchiatti Ilaria , Lattanzio Rosangela , Querques Giuseppe , Querques Lea , Del Turco Claudia , Cascavilla Maria Lucia , Bandello Francesco
Published: February 2012

Purpose: To evaluate the effects of a single injection of Ozurdex over 6 months in eyes with persistent diabetic macular edema (DME). Methods: In this retrospective interventional study, 9 patients with decreased visual acuity, as a result of persistent DME, received Ozurdex (intravitreal dexamethasone implant 0.7 mg). Main outcome measures included changes in best-corrected visual acuity (BCVA) and central retinal thickness (CRT). Results: Nine eyes of 9 patients (5 males, 4 females; mean age 58 years) were included in the analysis. The mean duration of DME was 49.9 months (range 24–85). All patients had undergone previous treatments for DME (intravitreal injection of anti-vascular endothelial growth factor, steroids or laser photocoagulation) before entering the study. At baseline, the mean BCVA was 0.74 ± 0.33 logMAR, and the mean CRT was 502 ± 222.16 µm. The mean BCVA was unchanged on the third day (0.74 ± 0.38 logMAR, p = 0.5), improved to 0.62 ± 0.32 logMAR (p = 0.02), 0.59 ± 0.26 logMAR (p = 0.02) and 0.63 ± 0.38 logMAR (p = 0.6) after the first, third and fourth months, respectively, and decreased again to 0.73 ± 0.35 logMAR (p = 0.4) at 6 months. The mean CRT improved to 397 ± 115.31 µm (p = 0.17), 271 ± 99.97 µm (p = 0.007), 325 ± 133.05 µm (p = 0.03) and 462 ± 176.48 µm (p = 0.36) on the third day and after 1, 3 and 4 months of follow-up and then increased again to 537 ± 265.42 µm (p = 0.33) at 6 months. Eight patients needed retreatments in the sixth month. One eye developed a transient intraocular pressure (IOP) increase 1 month after injection, which was successfully managed with topical IOP-lowering medication. Conclusion: In eyes with persistent DME, Ozurdex produces improvement in BCVA and CRT as soon as the first days after the injection. Such improvement is maintained until the fourth month.
Ischemic Transient Neurological Events Identified by Immune Response to Cerebral Ischemia
Authors: Jickling Glen C. , Zhan Xinhua , Stamova Boryana , Ander Bradley P. , Tian Yingfang , Liu Dazhi , Sison Shara-Mae , Verro Piero , Johnston S. Claiborne , Sharp Frank R.
Published: February 2012

Background and Purpose—

Deciphering whether a transient neurological event (TNE) is of ischemic or nonischemic etiology can be challenging. Ischemia of cerebral tissue elicits an immune response in stroke and transient ischemic attack (TIA). This response, as detected by RNA expressed in immune cells, could potentially distinguish ischemic from nonischemic TNE.

Methods—

Analysis of 208 TIAs, ischemic strokes, controls, and TNE was performed. RNA from blood was processed on microarrays. TIAs (n=26) and ischemic strokes (n=94) were compared with controls (n=44) to identify differentially expressed genes (false discovery rate <0.05, fold change ≥1.2). Genes common to TIA and stroke were used predict ischemia in TIA diffusion-weighted imaging-positive/minor stroke (n=17), nonischemic TNE (n=13), and TNE of unclear etiology (n=14).

Results—

Seventy-four genes expressed in TIA were common to those in ischemic stroke. Functional pathways common to TIA and stroke related to activation of innate and adaptive immune systems, involving granulocytes and B cells. A prediction model using 26 of the 74 ischemia genes distinguished TIA and stroke subjects from control subjects with 89% sensitivity and specificity. In the validation cohort, 17 of 17 TIA diffusion-weighted imaging-positive/minor strokes were predicted to be ischemic, and 10 of 13 nonischemic TNE were predicted to be nonischemic. In TNE of unclear etiology, 71% were predicted to be ischemic. These subjects had higher ABCD
2
scores.

Conclusions—

A common molecular response to ischemia in TIA and stroke was identified, relating to activation of innate and adaptive immune systems. TNE of ischemic etiology was identified based on gene profiles that may be of clinical use once validated.
Lipid and Lipoprotein Biomarkers and the Risk of Ischemic Stroke in Postmenopausal Women
Authors: Berger Jeffrey S. , McGinn Aileen P. , Howard Barbara V. , Kuller Lewis , Manson JoAnn E. , Otvos Jim , Curb J. David , Eaton Charles B. , Kaplan Robert C. , Lynch John K. , Rosenbaum Daniel M. , Wassertheil-Smoller Sylvia
Published: February 2012

Background—

Few studies simultaneously investigated lipids and lipoprotein biomarkers as predictors of ischemic stroke. The value of these biomarkers as independent predictors of ischemic stroke remains controversial.

Methods—

We conducted a prospective nested case-control study among postmenopausal women from the Women's Health Initiative Observational Study to assess the relationship between fasting lipids (total cholesterol, low-density lipoprotein cholesterol [LDL-C], high-density lipoprotein cholesterol [HDL-C], and triglycerides), lipoproteins (LDL, HDL, and very low-density lipoprotein [VLDL] particle number and size, intermediate-density lipoprotein [IDL] particle number, and lipoprotein (a)), and risk of ischemic stroke. Among women free of stroke at baseline, 774 ischemic stroke patients were matched according to age and race to control subjects, using a 1:1 ratio.

Results—

In bivariate analysis, baseline triglycerides (
P
<0.001), IDL particles (
P
<0.01), LDL particles (
P
<0.01), VLDL triglyceride (
P
<0.001), VLDL particles (
P
<0.01), VLDL size (
P
<0.001), LDL size (
P
=0.03), and total/HDL cholesterol ratio (
P
<0.01) were significantly higher among women with incident ischemic stroke, whereas levels of HDL-C (
P
<0.01) and HDL size (
P
<0.01) were lower. No significant baseline difference for total cholesterol (
P
=0.15), LDL-C (
P
=0.47), and lipoprotein (a) (
P
=0.11) was observed. In multivariable analysis, triglycerides (odds ratio for the highest versus lowest quartile, 1.56; 95% confidence interval, 1.13–2.17;
P
for trend=0.02), VLDL size (odds ratio, 1.59; 95% confidence interval, 1.10–2.28;
P
for trend=0.03), and IDL particle number (odds ratio, 1.46; 95% confidence interval, 1.04–2.04;
P
for trend=0.02) were significantly associated with ischemic stroke.

Conclusions—

Among a panel of lipid and lipoprotein biomarkers, baseline triglycerides, VLDL size, and IDL particle number were significantly associated with incident ischemic stroke in postmenopausal women.
Seven-Day NIHSS Is a Sensitive Outcome Measure for Exploratory Clinical Trials in Acute Stroke
Authors: Kerr Daniel M. , Fulton Rachael L. , Lees Kennedy R. ,   for the VISTA Collaborators
Published: February 2012

Background and Purpose—

Clinical trials in stroke typically measure outcome after 90 days. Earlier outcome assessment would reduce costs and may increase power. We aimed to compare the sensitivity of 4 end points (modified Rankin Scale [mRS] at 30 and 90 days, and National Institutes of Health Stroke Scale (NIHSS) at 7 and 90 days, analyzed as ordinal measures) to detect the established treatment effect of recombinant tissue-type plasminogen activator (rtPA).

Methods—

Within the Virtual International Stroke Trials Archive, we compared rtPA–treated patients with untreated control subjects using a multiple resampling approach. From our total sample we drew 10 000 random samples of unique patients, constraining the sample sizes in treated and untreated groups to be equal. In each of these samples we tested for the treatment effect of rtPA by each of the 4 studied end points. The percentage of samples yielding significant results approximates the power of each end point at a given sample size. This process was repeated across a range of sample sizes, to determine the relationship between sample size and power for each of the 4 end points.

Results—

For our 4 end points of mRS at 30 and 90 days, and NIHSS at 7 and 90 days the smallest sample sizes required to generate statistical power >80% were 620, 480, 370, and 420, respectively, making 7-day NIHSS the most sensitive end point. These results were supported by dichotomized analyses.

Conclusions—

Seven-day NIHSS score appears a sensitive end point that should be validated in randomized trial datasets for use in exploratory stroke trials.
Luke and the Septuagint
Authors: Muraoka Takamitsu
Published: February 2012

Abstract

The choice of Greek words in two passages in the Lukan Gospel appears to suggest that the Evangelist was consciously drawing upon two OT passages in its Greek version, i.e. the LXX. This close dependence on the LXX was motivated by the thematic affinity between the Lukan passages and their respective LXX passages.