bluuebunny/crossref_metadata_2025 huggingface dataset:
Neuronal Activity During Different Behaviors in
Aplysia
: a Distributed Organization?
Authors: Wu Jian-young , Cohen Lawrence B. , Falk Chun Xiao
Published: October 2006

The active neuronal populations in the
Aplysia
abdominal ganglion during spontaneous and evoked behaviors were compared with the use of multineuronal optical measurements. In some preparations, more than 90 percent of the neurons activated during the reflex withdrawal of the gill also were activated during respiratory pumping and during small spontaneous gill contractions. Although the same neurons made action potentials in all three behaviors, the activity patterns were different. There was a substantial interaction between the neural substrates underlying evoked and spontaneous behaviors when they were made to occur together. If a gill withdrawal reflex was elicited a few seconds after a respiratory pumping episode, the evoked neuronal activity in most neurons was clearly altered. These results suggest that a distributed organization involving a large number of neurons may be responsible for generating the two behaviors. Different behaviors appear to be generated by altered activities of a single, large distributed network rather than by small dedicated circuits.
Laser-Based Analysis of Carbon Isotope Ratios
Authors: Murnick D. E. , Peer B. J.
Published: October 2006

A laser technique for analysis of carbon-13:carbon-12 ratios with the specificity of laser resonance spectroscopy and the sensitivity and accuracy typical of isotope ratio mass spectrometers is reported. The technique is based on laser optogalvanic effect spectroscopy, in which an electrical (galvanic) signal is detected in response to the optical stimulation of a resonance transition in a gas discharge species. Carbon dioxide molecular gas lasers are used, with the probed transitions being identical to the lasing transitions. Measurements for carbon dioxide samples with 100-second averaging times yield isotopic ratios with a precision of better than 10 parts per million.
Reduction in Viscosity of Cystic Fibrosis Sputum in Vitro by Gelsolin
Authors: Vasconcellos Carol A. , Allen Philip G. , Wohl Mary Ellen , Drazen Jeffrey M. , Janmey Paul A. , Stossel Thomas P.
Published: October 2006

Obstruction of airways by viscous sputum causes lung damage in patients with cystic fibrosis (CF). Sputum samples from CF patients were shown to contain filamentous actin. Human plasma gelsolin, a protein that severs actin filaments, rapidly decreased the viscosity of CF sputum samples in vitro. Gc globulin and deoxyribonuclease I, proteins that sequester monomeric actin but do not sever actin filaments, were less efficient than gelsolin in diminishing sputum viscosity. These results suggest that gelsolin may have therapeutic potential as a mucolytic agent in CF patients.
Kinetics of Molecular Chaperone Action
Authors: Schmid Daniel , Baici Antonio , Gehring Heinz , Christen Philipp
Published: October 2006

Molecular chaperones of the Hsp70 type transiently sequester unfolded segments of proteins and promote their correct folding. Target peptides were labeled with an environmentally sensitive fluorophore so that their binding to the molecular chaperone DnaK of
Escherichia coli
could be followed in real time. The two-step process was characterized by relaxation times of 27 seconds and 200 seconds with 2 μM DnaK and 0.1 μM ligand at 25°C. In the presence of adenosine triphosphate, the formation of the complex was greatly accelerated and appeared to be a single-exponential process with a relaxation time of 0.4 second. The binding-release cycle of DnaK thus occurs in the time range of polypeptide chain elongation and folding and is too fast to be stoichiometrically coupled to the adenosine triphosphatase activity of the chaperone (turnover number, 0.13 per minute at 30°C).
Paralysis and Early Death in Cysteine String Protein Mutants of
Drosophila
Authors: Zinsmaier Konrad E. , Eberle Kai K. , Buchner Erich , Walter Niklaus , Benzer Seymour
Published: October 2006

Multimeric complexes of synaptic vesicle and terminal membrane proteins are important components of the neurotransmitter release mechanism. The
csp
gene of
Drosophila
encodes proteins homologous to synaptic vesicle proteins in
Torpedo
. Monoclonal antibodies demonstrate different distributions of isoforms at distinct subsets of terminals. Deletion of the
csp
gene in
Drosophila
causes a temperature-sensitive block of synaptic transmission, followed by paralysis and premature death.
Comparison of the Proteosomes and Antigenicities of Secreted and Cellular Proteins Produced byMycobacterium paratuberculosis
Authors: Cho Donghee , Collins Michael T.
Published: October 2006

The protein expression profiles and antigenicities of both culture filtrates (CF) and cellular extracts (CE) ofMycobacterium paratuberculosiswere compared by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), one-dimensional electrophoresis (1-DE) and 2-DE immunoblotting, and enzyme-linked immunosorbent assay (ELISA). The CF proteins were harvested from supernatants of stationary-phase liquid cultures and concentrated by size exclusion filtration. The CE proteins were extracted by mechanical disruption of cells using glass beads and a high-speed agitator. Analysis of SDS-PAGE gels showed that the majority of CF proteins had low molecular masses (<50 kDa), whereas CE protein mass ranged more evenly over a broader range up to 100 kDa. By 2-DE, CF proteins had a narrow array of pI values, with most being between pH 4.0 and 5.5; CE proteins spanned pI values from pH 4.0 to 7.0. The antigenicities of CF and CE proteins were first determined by 1-DE and 2-DE immunoblotting with serum from a cow naturally infected withM. paratuberculosis. The serum reacted strongly to more proteins in the CF than the CE. Sera from 444 infected and 412 uninfected cattle were tested by ELISA with CF and CE as solid-phase antigens. Receiver-operator characteristic curve analysis of the ELISA results showed a significantly greater area under the curve for CF compared to CE (P< 0.05). A high degree of variability in protein binding patterns was shown with 1-DE immunoblot analysis with 31 sera fromM. paratuberculosis-infected cattle. Collectively, these results indicate that serologic tests for bovine paratuberculosis may be improved by using proteins derived from CF instead of CE. To maximize the diagnostic sensitivity of serologic tests, multiple proteins will be required. Even so, a CF ELISA may not be able to detect allM. paratuberculosis-infected cattle, in particular those in the early stages of infection that have yet to mount an antibody response.
Analysis of Antibody Response in Humans to the Type A OspC Loop 5 Domain and Assessment of the Potential Utility of the Loop 5 Epitope in Lyme Disease Vaccine Development
Authors: Buckles Eric L. , Earnhart Christopher G. , Marconi Richard T.
Published: October 2006

The OspC protein of
Borrelia burgdorferi
is an immunodominant antigen. Here we demonstrate that the loop 5 domain of type A OspC is surface exposed, elicits bactericidal antibody in mice, and is antigenic in humans. The data suggest that loop 5 may be suitable for inclusion in a polyvalent, chimeric OspC vaccinogen.
Evaluation of a Rapid Fecal PCR Test for Detection ofMycobacterium aviumsubsp.paratuberculosisin Dairy Cattle
Authors: Wells Scott J. , Collins Michael T. , Faaberg Kay S. , Wees Carrie , Tavornpanich Saraya , Petrini Kristine R. , Collins James E. , Cernicchiaro Natalia , Whitlock Robert H.
Published: October 2006

A high-throughput TaqMan PCR assay for detection of bovine paratuberculosis was evaluated by using fecal samples from 1,808 dairy cattle in seven naturally infected herds and 347 dairy cattle in seven herds considered free of paratuberculosis. Fecal, blood, and milk samples were submitted to laboratories where the PCR-based assay, three different fecal culture procedures forMycobacterium aviumsubsp.paratuberculosis(centrifugation, sedimentation, and the BACTEC filter concentration method), two serologic enzyme-linked immunosorbent assays (ELISAs), and one milk ELISA were performed. Results from testing of dairy cattle in herds free ofM. aviumsubsp.paratuberculosisshowed that the PCR assay's specificity was 99.7%. Twenty-three percent of the dairy cows that were fecal culture positive by at least one of the three methods were positive by the PCR assay. By Bayesian non-“gold standard” analysis methods, the TaqMan PCR assay had a higher specificity than the serum ELISAs (99.3%; 95% confidence interval [CI] = 98.6 to 99.7%) and a test sensitivity similar to that of the serum ELISAs (29%; 95% CI = 24 to 35%). By classical methods, the estimated relative sensitivity of the fecal PCR assay was 4% for light and moderate fecal shedders (compared to 12 to 13% for the ELISAs) and 76% for heavy fecal shedders (compared to 67% for the milk ELISA). The PCR assay has higher sensitivity for detection of heavy fecal shedders than the evaluated milk ELISA but lower sensitivity than a serum or milk ELISA for detection of light and moderate fecal shedders. This assay can be used as a quick test for detection of cattle with heavy fecal shedding, those cattle with the highest risk of transmitting infection to susceptible cattle.
Serum Antibodies to Pneumococcal Neuraminidase NanA in Relation to Pneumococcal Carriage and Acute Otitis Media
Authors: Simell Birgit , Jaakkola Teija , Lahdenkari Mika , Briles David , Hollingshead Susan , Kilpi Terhi M. , Käyhty Helena
Published: October 2006

Pneumococcal neuraminidase, NanA, is a pneumococcal vaccine candidate. Prior culture-confirmed pneumococcal contacts were shown to induce serum anti-NanA antibodies during the first 2 years of life. The antibody concentrations at neither 12 nor 18 months were significantly associated with the risk of subsequent pneumococcal carriage or acute otitis media.
ASYMPTOTICS OF A 3F2 POLYNOMIAL ASSOCIATED WITH THE CATALAN–LARCOMBE–FRENCH SEQUENCE
Authors: TEMME NICO M.
Published: October 2006

The large n behavior of the hypergeometric polynomial [Formula: see text] is considered by using integral representations of this polynomial. This 3F2 polynomial is associated with the Catalan–Larcombe–French sequence. Several other representations are mentioned, with references to the literature, and another asymptotic method is described by using a generating function of the sequence. The results are similar to those obtained by Clark (2004) who used a binomial sum for obtaining an asymptotic expansion.
ON SOME NONLOCAL VARIATIONAL PROBLEMS
Authors: CHIPOT MICHEL , GANGBO WILFRID , KAWOHL BERND
Published: October 2006

We study uniqueness and non uniqueness of minimizers of functionals involving nonlocal quantities. We give also conditions which lead to a lack of minimizers and we show how minimization on an infinite dimensional space reduces here to a minimization on ℝ. Among other things, we prove that uniqueness of minimizers of functionals of the form ∫Ω a(∫Ω gu dx)|∇u|2 dx - 2 ∫Ω fu dx is ensured if a > 0 and 1/a is strictly concave in the sense that (1/a)″ < 0 on (0, ∞).
ON SOME BOUNDARY VALUE PROBLEM FOR THE STOKES EQUATIONS IN AN INFINITE SECTOR
Authors: ITOH SHIGEHARU , TANAKA NAOTO , TANI ATUSI
Published: October 2006

As a model problem of the stationary free boundary problem for the Navier–Stokes equations in a vessel whose wall has a contact with a free surface, we are concerned in this paper with the boundary value problem for the stationary Stokes equations in an infinite sector with the slip and the stress boundary conditions. Existence of the unique solution is proved in weighted Sobolev spaces by means of the Mellin transform.
Tensile-Strained Single-Crystal Si Film on Insulator by Epitaxially Seeded and Laser-Induced Lateral Crystallization
Authors: Cho Hans S. , Xianyu Wenxu , Zhang Xiaoxin , Yin Huaxiang , Noguchi Takashi
Published: October 2006

Tensile-strained single-crystal silicon films on insulator islands have been grown from Si wafer substrates by a process combining selective epitaxial growth (SEG) and pulsed laser crystallization. An amorphous Si film on an insulator island is completely melted by a single excimer laser pulse, leading to the solidification of the molten Si seeded from epitaxially grown single-crystal Si regions. Analyses of the resulting microstructures reveal that the laterally crystallized film is single-crystalline. A tensile strain of up to 8.8×10-3 within the crystallized region was measured by Raman spectroscopy. The tensile-strained Si film has potential applications in high-performance devices for three-dimensionally stacked integrated circuits.
Diamagnetic Susceptibility of Multiwall Carbon Nanotubes with Open and Closed Ends
Authors: Kawamura Kiyoshi , Muramatsu Naoki
Published: October 2006

The diamagnetic susceptibility of multiwall carbon nanotubes with open and closed ends is measured as a function of temperature between liquid helium and room temperatures. A λ-shaped temperature dependence of magnetic susceptibility is observed at around 40 K, in particular, for the specimen with open ends. Repeating the measurements results in a decrease in the peak height and also in flattening the peak. This implies that alignment of the tube axis in parallel to the magnetic field is responsible for this result. Therefore, the λ-shaped temperature dependence is considered to be characteristic of magnetic susceptibility measured in a field perpendicular to the tube axis.
Design, Fabrication, and Characterization of Tunable Micromachined Filter with Double-Cavity Structure
Authors: Janto Wiganes , Matsutani Akihiro , Koyama Fumio
Published: October 2006

In this study, we demonstrated micromachined double-cavity optical filters with a narrow 3 dB bandwidth of ∼0.7 nm in reflection spectra. These double-cavity filters exhibited a sharper and flatter response than conventional single-cavity filters, resulting in a lower crosstalk. We were able to reduce filter bandwidth by increasing the number of distributed Bragg reflector (DBR) layers to be 18.5, 45.5, and 16.5 pairs of GaAs/AlGaAs layers at the top, in the middle, and at the bottom of the filters, respectively. The thermal wavelength tuning of the filters was demonstrated with the aid of thermal strain in movable cantilevers. For the heating of the p–n junction in the cantilevers, the filters exhibited a continuous tuning range of ∼7 nm with an applied voltage of 15 V. The temperature dependence of filter wavelength was experimentally investigated using an external heater, which the filters showed a linear temperature sensitivity. In addition, the extinction ratios of reflection spectra were maintained at ∼12 dB over the entire tuning range.
Microcell Liquid Crystal Film for High-Contrast Flexible Display Applications
Authors: Liu Kang-Hung , Chou Wei-Yang , Liao Chi-Chang , Ho Cheng-Ta , Shieh Han-Ping D.
Published: October 2006

We have successfully fabricated high-contrast microcell liquid crystal displays (LCDs) using microstructure replication technology in thin plastic film substrates. These novel flexible LCDs comprise microcell replication, alignment treatments, and cell assembly. The cell gap of such flexible LCDs was maintained well by cross-type spacers formed by photolithography, despite bending: moreover, the deviation in cell gap under various bending states was less than 0.1 µm. The structure, fabrication technique, and basic display characteristics of the flexible LCD are also described. Finally, this device shows high mechanical stability against external bending, a high contrast ratio of 500:1, and an acceptable response time. Compared with photopolymerisation-induced phase separation, the micro-cell LCD has a higher contrast ratio, a more reliable fabrication process, and a strong potential as a high-performance flexible LCD.
Submersion Sensor with Side-Polished Fiber and Planar Waveguide in Manhole
Authors: Lee Cherl-Hee , Lee Dong-Ho , Kwon Kwang-Hee , Song Jae-Won
Published: October 2006

Experiments are conducted to investigate whether a side-polished fiber sensor can detect submersion without being affected by water impurities when a manhole is submerged. The side-polished fiber sensor is also examined whether it can detect submersion when the overlay of such sensor is covered with impurities.
Effect of Thickness on the Structure and Properties of ZnO Thin Films Prepared by Pulsed Laser Deposition
Authors: Zhu Bai Lin , Sun Xiao Hua , Guo Shi Shang , Zhao Xing Zhong , Wu Juan , Wu Run , Liu Jing
Published: October 2006

ZnO thin films with various thicknesses were prepared onto glass substrates by pulsed laser deposition. The crystallinity, microstructure and surface morphology of ZnO thin films were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and scanning probe microscopy (SPM). As the thickness of the films increased, the grain size and the surface roughness increased as well the tensile stress decreased. Also, to study the optical-electrical properties of the films, we tested the carrier concentration, mobility, resistivity, impedance spectroscopy and optical transmission spectra. The results showed that the carrier concentration gradually increased as the thickness increased from 20 to 106 nm, thereafter decreased as the thickness further increased to 216 nm. The main contribution to the conduction of the films with thickness from 20 to 106 nm gradually converted from grain boundaries to grains, and converted into grain boundaries again for the films with a thickness of 216 nm. As the thickness of the films decreased, it was found that the blue shift of absorption edge of optical transmission spectra. Effects of the thicknesses on the optical and electrical properties for ZnO films were related to their grain size, stress and carrier concentration.
Correlation of Grain Size of Pentacene-Deposited Surface and Carbon Content Analyzed by X-ray Photoelectron Spectroscopy
Authors: Kim Hong Bae , Oh Teresa
Published: October 2006

The surfaces of SiO2 films were treated using n-octadecyltrichlorosilane diluted solution, their chemical properties were analyzed by X-ray photoelectron spectroscopy, and their leakage currents were determined using current–voltage (I–V) measurements. The resultant thin film was composed of Si, O, and C atoms, and Cl atoms did not participate in the chemical reaction mechanism. SiO2 films changed from having inorganic to having organic properties, according to the increasing N-octadecyltrichlorosilane (OTS) content. Grain size and leakage current were found to be related to the carbon content and the perpendicular generation of pentacene molecules. Grain size and leakage current decreased for the sample with the lowest carbon content. The 0.2%-OTS-treated SiO2 films with hybrid properties had decreased leakage current.
Hollow-Cathode Based Electrical Discharge in Atmospheric Pressure Water Vapor at Wide Range of Temperature
Authors: Koo Il Gyo , Lee Woong Moo
Published: October 2006

Atmospheric pressure water vapor, in the temperature range from 150 to 700 °C, was used as the carrier gas for DC powered electrical discharge in hollow cathode configuration. The electrode assembly was constructed in usual hollow-cathode configuration by sandwiching a dielectric spacer, 200 µm thick, with two thin metal sheets and boring a micro hole of 300 µm diameter. The current–voltage profile of the discharge showed a positive differential resistivity characterizing an abnormal glow discharge. The power consumption for the water discharge at 700 °C was less than 50% the consumption at 150 °C. The reduction of the power for sustaining the discharge with increase of the gas temperature was partly explained by relating the ionic mobility and the distribution of ionic mean free path to the temperature.
Improvement of Power Transmission for Fundamental Electron Cyclotron Resonance Heating System in GAMMA 10 Central Cell
Authors: Tatematsu Yoshinori , Machida Norihito , Saito Teruo , Nozaki Kiyoshi , Nagai Daichi , Nakamura Maria , Kaitsuka Tetsuya , Kamata Yasuhiro , Watanabe Osamu , Kubo Shin , Shimozuma Takashi , Imai Tsuyoshi , Cho Teruji
Published: October 2006

For improvement of the central-cell electron cyclotron resonance heating (C-ECRH) system in GAMMA 10, a new launcher has been designed. The new launcher consists of one mirror and an open-ended waveguide with an inner diameter of D=45 mm, which is larger than D=31.75 mm in the present launcher. The shape of the mirror installed under the open end of the waveguide is determined with our electromagnetic code for the radiation profile to be axisymmetrical on the resonance surface. The power transmission rate of the microwave beam to the resonance surface increases, and the total Poynting flux reaching the plasma becomes 88%, which is about 1.5 times larger than that obtained by the present launcher. Transmission rate is confirmed by a test measurement with a low-power source. When using a waveguide with a larger D of 63.5 mm, the power transmission rate increases and reaches 95%.
Low-Temperature Fabrication of TiO2 Necking Electrode by Sol–Gel Method and its Application to Dye-Sensitized Solar Cell
Authors: Murayama Masaki , Yamazaki Eiji , Nishikawa Naomi , Hashimoto Noritsugu , Mori Tatsuo
Published: October 2006

The low-temperature fabrication of TiO2 electrodes for use in a dye-sensitized solar cell was studied. The use of the sol–gel necking method with a Ti–precursor solution added to a paste including TiO2 nano particles resulted in a high-performance TiO2 electrode. A solar cell using the electrode showed a high efficiency of almost 2%, even when sintered at 200 °C. The improvement in the efficiency was due to the increase in photocurrent of the cell. Increasing the specific surface area of the TiO2 electrode sintered at around 200 °C was corresponded to an increase in the number of micropores. However, it did not contribute to the increase in the amount of adsorbed dye nor did it improve photocurrent. Rather, the crystallization of the added Ti–precursor solution and subsequent increase in conductivity of the TiO2 electrode improved photocurrent. The phase transition temperature of the Ti–precursor solution from amorphous to anatase was detected at 331 °C by differential thermal analysis (DTA) measurement. To fabricate the TiO2 electrode for use in a high-performance solar cell at lower temperatures, the control of crystallization is required.
Shrinkage Process with Cure and Bake
Authors: Sasaki Suguru , Watanabe Minoru , Taguchi Takashi
Published: October 2006

Electron beam (EB) and ultraviolet (UV) have a curing effect on resist patterns. We found that high-temperature baking can shrink patterns cured using EB or vacuum ultraviolet (VUV). Critical dimension (CD) measurements were performed after baking. It was found that CD decreased with increasing baking temperature and the CD deviation after the postcure baking was almost the same as that of the initial pattern. Sub-100 nm line patterns were successfully fabricated by shrinking about 35 nm upon 350 °C postcure bake without pattern reflow. It was demonstrated that the CD shrinkage process has a high CD controllability due to the low dependence of shrinkage on baking temperature and the nondependence of shrinkage on pattern pitch, and the process does not influence CD deviation.
Basic Characteristics of Axial Scanner of Optical Coherence Tomography with Cylindrical Piezoelectric Transducer
Authors: Takahashi Yoshiyuki , Iwaya Mitsuharu , Watanabe Yuuki , Sato Manabu
Published: October 2006

We have investigated the basic characteristics (scan depth, linearity, and stability) of a piezoelectric axial scanner (PAS) composed of optical fibers wound around a cylindrical piezoelectric transducer. The scan depth due to the stretching of the fibers is decreased to 77.5% by the photoelastic effect. With the application of a high voltage pseudo-triangular signal to two PASs, a scan depth of 2 mm and scan rate of 2,000 lines/s were achieved and used to acquire a cross-sectional image of an in vivo human finger with a measurement time of 0.5 s.
Structures of Anodized Aluminum Oxide Extended-Gate Field-Effect Transistors on pH Sensors
Authors: Lin Jyh-Ling , Chu Yung-Ming , Hsaio Shih-Hua , Chin Yuan-Lung , Sun Tai-Ping
Published: October 2006

The objective of this work is the study and characterization of anodized aluminum oxide as a pH sensor. Sensing films were fabricated by anodic oxidation, a process which is low cost, in which it is simple to manufacture and mass produce films at room temperature, in which it is easy to control the variation in film resistance. The films have a good linear sensitivity, approximately 56 mV/pH from pH 4 to 10 when an instrumentation amplifier is used as the read out circuit. This study indicates that the type of aluminum substrate affects the sensing characteristics. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis show that aluminum oxides on different aluminum substrates formed by anodic oxidation have various acid-base characteristics. Extended-gate field-effect transistor (EGFET) sensing films formed when the predominant surface plane of the aluminum oxide is (012) have a linear sensitivity.
Enhanced Magnification Angiography Using 20-µm-Focus Tungsten Tube
Authors: Enomoto Toshiyuki , Sato Eiichi , Sumiyama Yoshinobu , Aizawa Katsuo , Watanabe Manabu , Tanaka Etsuro , Mori Hidezo , Kawakami Hiroki , Kawai Toshiaki , Inoue Takashi , Ogawa Akira , Sato Shigehiro
Published: October 2006

A microfocus X-ray tube is useful for performing magnification radiography, and its X-ray generator (L9631, Hamamatsu Photonics) consists of a personal computer for controlling the tube voltage and current, and a main unit with a high-voltage circuit and a fixed-anode X-ray tube. The maximum tube voltage, current, and electric power were 110 kV, 800 µA, and 50 W, respectively. The focal-spot size was proportional to the electric power of the tube, and the size was approximately 20 µm with a power of 20 W. Using a 3-mm-thick aluminum filter, the X-ray intensity was 7.75 µGy/s at 1.0 m from the source with a tube voltage of 60 kV and a current of 100 µA. Because the peak photon energy was approximately 38 keV using the filter with a tube voltage of 60 kV, the bremsstrahlung X-rays were absorbed effectively by iodine-based contrast media at an iodine K-edge of 33.2 keV. Enhanced angiography was performed by fourfold magnification imaging with a computed radiography system using iodine-based microspheres 15 µm in diameter. In the angiography of nonliving animals, we observed fine blood vessels of approximately 100 µm with high contrast.
Effect of Ca addition on Grain Size and Crystal Phase of Barium Titanate Nanopowders
Authors: Tikhonovsky Alexander , Kim Kihong , Lee Sang Kyun , Nedoseykina Tatiana , Yang Mino , Song Se Ahn
Published: October 2006

The effect of 2.5 at. % Ca addition on the grain size and crystal lattice of hydrothermally produced barium titanate nanopowders was studied by field-emission transmission electron microscopy (FE-TEM). The fabrication of the nanopowders involved the heat treatment of Ba0.975Ca0.025TiO3 and BaTiO3 powders. The grain growth of Ba0.975Ca0.025TiO3 particles is inhibited by the Ca coating. A pore region is observed in both types of particles and the average size of the pores depends on the calcination temperature. In addition, the crystal structure of the nanoparticles was investigated with high-resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). These methods show that both powders have a crystalline structure with lattice planes typical for a perovskite structure. The lattice shrinkage is explained by Ca substitution at the Ba atomic positions in the unit cell of barium titanate, and the tetragonal lattice distortion is accounted for by Ca substitution at the Ti sites in the perovskite structure. X-ray absorption fine structure (XAFS) analysis shows that the local atomic structures around Ti in Ba0.975Ca0.025TiO3 and BaTiO3 particles are more highly ordered compared with pure single-crystalline BaTiO3.
Quantum Neural Network Composed of Kane's Qubits
Authors: Nakamiya Yuuki , Kinjo Mitsunaga , Takahashi Osamu , Sato Shigeo , Nakajima Koji
Published: October 2006

It has been known that a variety of optimization problems can be solved with a neural network, and that a quantum computer executes real parallel computation. A quantum neural network has been proposed to incorporate quantum dynamics into a neural network. In this study, we test the possibility of actual implementation of a quantum neural network with a nuclear spin as a qubit. First, we introduce the relationship between a spin and a neuron, then describe the adiabatic Hamiltonian evolution applied for the state change. Next, we describe a real spin quantum system and show the simulation results. A proposed nuclear spin system behaves as a neuron with inhibitory interactions, as expected in analogy to a Hopfield network.
Increased intestinal permeability in obese mice: new evidence in the pathogenesis of nonalcoholic steatohepatitis
Authors: Brun Paola , Castagliuolo Ignazio , Leo Vincenza Di , Buda Andrea , Pinzani Massimo , Palù Giorgio , Martines Diego
Published: October 2006

A small percentage of pathologically obese subjects with fatty livers develop histological signs of necroinflammation and fibrosis, suggesting a variety of cofactors in the pathogenesis of obesity-related liver diseases including nonalcoholic steatohepatitis. Since several observations have linked bacterial endotoxins to liver damage, the aim of this study was to determine the effect of obesity on intestinal mucosal integrity and portal blood endotoxemia in two strains of obese mice: leptin-deficient ( ob/ ob) and hyperleptinemic ( db/ db) mice. Murine intestinal mucosal barrier function was assessed using a Ussing chamber, whereas ileum tight junction proteins were analyzed by immunocytochemistry and Western blot analysis. Circulating proinflammatory cytokines and portal blood endotoxin levels were measured by ELISA and the limulus test, respectively. The inflammatory and fibrogenic phenotype of murine hepatic stellate cells (HSCs) was determined by ELISA and quantitative RT-PCR. Ob/ ob and db/ db mice showed lower intestinal resistance, profoundly modified distribution of occludin and zonula occludens-1 in the intestinal mucosa, and higher circulating levels of inflammatory cytokines and portal endotoxemia compared with lean control mice. Moreover, HSCs isolated from ob/ ob and db/ db mice showed higher membrane CD14 mRNA levels and more pronounced lipopolysaccharide-induced proinflammatory and fibrogenic responses than HSCs from lean animals. In conclusion, genetically obese mice display enhanced intestinal permeability leading to increased portal endotoxemia that makes HSCs more sensitive to bacterial endotoxins. We suggest that in metabolic syndrome, patients may likewise have a greater intestinal mucosa permeability and increased lipopolysaccharide levels in portal blood that can contribute to the liver inflammatory damage.
Estrogen and isoflavone attenuate stress-induced gastric mucosal injury by inhibiting decreases in gastric tissue levels of CGRP in ovariectomized rats
Authors: Shimozawa Nobuhiko , Okajima Kenji , Harada Naoaki
Published: October 2006

We have previously reported that CGRP plays a critical role in the reduction of stress-induced gastric mucosal injury by increasing gastric prostacyclin (PGI2) levels in rats. Estrogen has been shown to increase the production of CGRP in sensory neurons. Isoflavone has estrogen-like effects and is referred to as a phytoestrogen. Thus, we hypothesized that estrogen and isoflavone might inhibit ovariectomy (OVX)-induced decreases in gastric tissue levels of CGRP, thereby attenuating gastric mucosal injury. We examined these possibilities in the present study. The administration of estradiol and isoflavone for 4 wk completely reversed OVX-induced decreases in CGRP mRNA levels of dorsal root ganglion neurons (DRGs) in rats. OVX-induced decreases in gastric tissue levels of CGRP and 6-keto-PGF1α, a stable metabolite of PGI2, in rats were reversed by estradiol and isoflavone. Water-immersion restraint stress (WIR)-induced increases in gastric tissue levels of CGRP and 6-keto-PGF1α were inhibited in ovariectomized rats. This inhibition was completely reversed by estradiol and was partially, but significantly, reversed by isoflavone. WIR-induced gastric mucosal injury was exacerbated by OVX, which was reversed by estradiol and isofolavone. In vitro experiments using DRGs isolated from rats demonstrated that neither estradiol nor isoflavone enhanced CGRP release from DRGs, but the former enhanced it in the presence of anandamide, an endogenous agonist for vanilloid receptor-1. These observations suggest that estrogen and isoflavone might inhibit OVX-induced decreases in CGRP levels in DRGs by promoting transcription, thereby contributing to the attenuation of stress-induced gastric mucosal injury in OVX rats.
Effects of pelvic floor muscle contraction on anal canal pressure
Authors: Padda Bikram S. , Jung Sung-Ae , Pretorius Dolores , Nager Charles W. , Den-Boer Debbie , Mittal Ravinder K.
Published: October 2006

The role of pelvic floor muscle contraction in the genesis of anal canal pressure is not clear. Recent studies have suggested that vaginal distension increases pelvic floor muscle contraction. We studied the effects of vaginal distension on anal canal pressure in 15 nullipara asymptomatic women. Anal pressure, rest, and squeeze were measured using station pull-through manometry techniques with no vaginal probe, a 10-mm vaginal probe, and a 25-mm vaginal probe in place. Rest and squeeze vaginal pressures were significantly higher when measured with the 25-mm probe compared with the 10-mm probe, suggesting that vaginal distension enhances pelvic floor contraction. In the presence of the 25-mm vaginal probe, rest and squeeze anal pressures in the proximal part of the anal canal were significantly higher compared with no vaginal probe or the 10-mm vaginal probe. On the other hand, distal anal pressures were not affected by any of the vaginal probes. Ultrasound imaging of the pelvic floor revealed that vaginal distension increased the anterior-posterior length of the puborectalis muscle. Atropine at 15 μg/kg had no influence on the rest and squeeze anal pressures with or without vaginal distension. Our data suggest that pelvic floor contractions increase pressures in the proximal part of the anal canal, which is anatomically surrounded by the puborectalis muscle. We propose that pelvic floor contraction plays an important role in the fecal continence mechanism by increasing anal canal pressure.
Activation of neural circuitry and Ca2+ waves in longitudinal and circular muscle during CMMCs and the consequences of rectal aganglionosis in mice
Authors: Spencer Nick J. , Bayguinov Peter , Hennig Grant W. , Park Kyu Joo , Lee Hyun-Tai , Sanders Kenton M. , Smith Terence K.
Published: October 2006

In mammals that develop rectal aganglionosis, the aganglionic segment still exhibits spontaneous phasic contractions that contribute to dysmotility and pseudoobstruction in this region. However, almost nothing is known about the mechanisms that generate these myogenic contractions or the effects of aganglionosis on the generation of Ca2+ waves that underlie contractions of the longitudinal muscle (LM) and circular muscle (CM). In a mouse model of Hirschsprung's disease [endothelin type B receptor-deficient ( Ednrb s−l/ Ednrb s−l) mice], the Ca2+ indicator fluo-4 was used to simultaneously monitor the temporal activation and spread of intercellular Ca2+ waves in the LM and CM during spontaneous colonic motor activities. During the intervals between colonic migrating motor complexes (CMMCs) in control mice, Ca2+ waves discharged asynchronously between the LM and CM. However, in these same mice, during CMMCs, a burst of discreet Ca2+ waves fired simultaneously in both muscle layers, where the propagation velocity of Ca2+ waves significantly increased, as did the rate of initiation and number of collisions between Ca2+ waves. Hexamethonium (300 μM) or atropine (1 μM) prevented synchronized firing of Ca2+ waves. In the aganglionic distal colon of Ednrb s−l/ Ednrb s−l mice, not only were CMMCs absent, but Ca2+ waves between the two muscle layers fired asynchronously, despite increased propagation velocity. The generation of CMMCs in control mice involves synchronized firing of enteric motor nerves to both the LM and CM, explaining the synchronized firing of discreet Ca2+ waves between the two muscle layers. Aganglionosis results in a sporadic and sustained asynchrony in Ca2+ wave firing between the LM and CM and an absence of CMMCs.
Characterization of the human intestinal CD98 promoter and its regulation by interferon-γ
Authors: Yan Yutao , Dalmasso Guillaume , Sitaraman Shanthi , Merlin Didier
Published: October 2006

Growing evidence that epithelial CD98 plays an important role in intestinal inflammation focused our interest to investigate the transcriptional regulation of CD98. Our mouse-based in vivo and in vitro experiments revealed that epithelial colonic CD98 mRNA expression was transcriptionally increased in intestinal inflammation. We then isolated and characterized a 5′-flanking fragment containing the promoter region required for CD98 gene transcription. Primer extension and rapid amplification of 5′-cDNA ends were used to map a transcriptional initiation site 129 bp upstream from the translational start codon (ATG). Direct sequencing of the 5′-flanking region revealed the presence of four GC-rich stimulating protein (Sp)1 binding domains, one NF-κB binding domain, and no TATA box. Binding of Sp1 [Sp1(−874), SP1(−386), Sp1(−187), and Sp1(−177)] and NF-κB [NF-κB(−213)] to the promoter was confirmed by EMSA and supershift assays. Furthermore, chromatin immunoprecipitation experiments showed the in vivo DNA-Sp1 and DNA-NF-κB interactions under basal and IFN-γ-stimulated conditions. Reporter genes driven by serially truncated and site-mutated CD98 promoters were used to examine basal and IFN-γ-responsive transcription in transiently transfected Caco2-BBE cells. Our results revealed that Sp1(−187), Sp1(−177), and the NF-κB binding site were essential for basal and IFN-γ-stimulated CD98 promoter activities, whereas Sp1(−874) and Sp1(−386) were not. The results from additional site-mutated CD98 promoters suggested that Sp1(−187), Sp1(−177), and the NF-κB site may cooperate in mediating basal and IFN-γ-stimulated CD98 promoter activities. Finally, we demonstrated that a reduction of Sp1 or NF-κB expression reduced CD98 protein expression in unstimulated and IFN-γ-stimulated Caco2-BBE cells. Collectively, these findings indicate that the Sp1 and NF-κB transcription factors are likely to play a significant role in IFN-γ-mediated transcriptional regulation of CD98 in the intestinal epithelium, providing new insights into the regulation of CD98 expression in intestinal inflammation.
Vagal afferents are essential for maximal resection-induced intestinal adaptive growth in orally fed rats
Authors: Nelson David W. , Liu Xiaowen , Holst Jens J. , Raybould Helen E. , Ney Denise M.
Published: October 2006

Small bowel resection stimulates intestinal adaptive growth by a neuroendocrine process thought to involve both sympathetic and parasympathetic innervation and enterotrophic hormones such as glucagon-like peptide-2 (GLP-2). We investigated whether capsaicin-sensitive vagal afferent neurons are essential for maximal resection-induced intestinal growth. Rats received systemic or perivagal capsaicin or ganglionectomy before 70% midjejunoileal resection or transection and were fed orally or by total parenteral nutrition (TPN) for 7 days after surgery. Growth of residual bowel was assessed by changes in mucosal mass, protein, DNA, and histology. Both systemic and perivagal capsaicin significantly attenuated by 48–100% resection-induced increases in ileal mucosal mass, protein, and DNA in rats fed orally. Villus height was significantly reduced in resected rats given capsaicin compared with vehicle. Sucrase specific activity in jejunal mucosa was not significantly different; ileal mucosal sucrase specific activity was significantly increased by resection in capsaicin-treated rats. Capsaicin did not alter the 57% increase in ileal proglucagon mRNA or the 150% increase in plasma concentration of bioactive GLP-2 resulting from resection in orally fed rats. Ablation of spinal/splanchnic innervation by ganglionectomy failed to attenuate resection-induced adaptive growth. In TPN rats, capsaicin did not attenuate resection-induced mucosal growth. We conclude that vagal afferents are not essential for GLP-2 secretion when the ileum has direct contact with luminal nutrients after resection. In summary, vagal afferent neurons are essential for maximal resection-induced intestinal adaptation through a mechanism that appears to involve stimulation by luminal nutrients.
Discoordinate regulation of renal nitric oxide synthase isoforms in ovariectomized mRen2.Lewis rats
Authors: Yamaleyeva Liliya M. , Gallagher Patricia E. , Vinsant Sharon , Chappell Mark C.
Published: October 2006

Estrogen depletion markedly exacerbates hypertension in female congenic mRen2.Lewis rats, a model of tissue renin overexpression. Because estrogen influences nitric oxide synthase (NOS) and NO may exert differential effects on blood pressure, the present study investigated the functional expression of NOS isoforms in the kidney of ovariectomized (OVX) mRen2.Lewis rats. OVX-mRen2.Lewis exhibited an increase in systolic blood pressure (SBP) of 171 ± 5 vs. 141 ± 7 mmHg ( P < 0.01) for intact littermates. Renal cortical mRNA and protein levels for endothelial NOS (eNOS) were reduced 50–60% ( P < 0.05) and negatively correlated with blood pressure. In contrast, cortical neuronal NOS (nNOS) mRNA and protein levels increased 100 to 300% ( P < 0.05). In the OVX kidney, nNOS immunostaining was more evident in the macula densa, cortical tubules, and the medullary collecting ducts compared with the intact group. To determine whether the increase in renal nNOS expression constitutes a compensatory response to the reduction in renal eNOS, we treated both intact and OVX mRen2.Lewis rats with the selective nNOS inhibitor L-VNIO from 11 to 15 wk of age. The nNOS inhibitor reduced blood pressure in the OVX group (185 ± 3 vs. 151 ± 8 mmHg, P < 0.05), but pressure was not altered in the intact group (146 ± 4 vs. 151 ± 4 mmHg). In summary, exacerbation of blood pressure in the OVX mRen2.Lewis rats was associated with the discoordinate regulation of renal NOS isoforms. Estrogen sensitivity in this congenic strain may involve the influence of NO through the regulation of both eNOS and nNOS.
The parathyroid hormone family of peptides: structure, tissue distribution, regulation, and potential functional roles in calcium and phosphate balance in fish
Authors: Guerreiro Pedro M. , Renfro J. Larry , Power Deborah M. , Canario Adelino V. M.
Published: October 2006

Parathyroid hormone (PTH) and PTH-related protein (PTHrP) are two factors that share amino acid sequence homology and act via a common receptor. In tetrapods, PTH is the main endocrine factor acting in bone and kidney to regulate calcium and phosphate. PTHrP is an essential paracrine developmental factor present in many tissues and is involved in the regulation of ossification, mammary gland development, muscle relaxation, and other functions. Fish apparently lack an equivalent of the parathyroid gland and were long thought to be devoid of PTH. Only in recent years has the existence of PTH-like peptides and their receptors in fish been firmly established. Two forms of PTH, two of PTHrP, and a protein with intermediate characteristics designated PTH-L are encoded by separate genes in teleost fish. Three receptors encoded by separate genes in fish mediate PTH/PTHrP actions, whereas only two receptors have so far been found in terrestrial vertebrates. PTHrP has been more intensively studied than PTH, from lampreys to advanced teleosts. It is expressed in many tissues and is present in high concentration in fish blood. Administration of this peptide alters calcium metabolism and has marked effects on associated gene expression and enzyme activity in vivo and in vitro. This review provides a comprehensive overview of the physiological roles, distribution, and molecular relationships of the piscine PTH-like peptides.
Sequential growth of fetal sheep cardiac myocytes in response to simultaneous arterial and venous hypertension
Authors: Jonker Sonnet S. , Faber J. Job , Anderson Debra F. , Thornburg Kent L. , Louey Samantha , Giraud George D.
Published: October 2006

While the fetal heart grows by myocyte enlargement and proliferation, myocytes lose their capacity for proliferation in the perinatal period after terminal differentiation. The relationship between myocyte enlargement, proliferation, and terminal differentiation has not been studied under conditions of combined arterial and venous hypertension, as occurs in some clinical conditions. We hypothesize that fetal arterial and venous hypertension initially leads to cardiomyocyte proliferation, followed by myocyte enlargement. Two groups of fetal sheep received intravascular plasma infusions for 4 or 8 days (from 130 days gestation) to increase vascular pressures. Fetal hearts were arrested in diastole and dissociated. Myocyte size, terminal differentiation (%binucleation), and cell cycle activity (Ki-67[+] cells as a % of mononucleated myocytes) were measured. We found that chronic plasma infusion greatly increased venous and arterial pressures. Heart (but not body) weights were ∼30% greater in hypertensive fetuses than controls. The incidence of cell cycle activity doubled in hypertensive fetuses compared with controls. After 4 days of hypertension, myocytes were (∼11%) longer, but only after 8 days were they wider (∼12%). After 8 days, %binucleation was ∼50% greater in hypertensive fetuses. We observed two phases of cardiomyocyte growth and maturation in response to fetal arterial and venous hypertension. In the early phase, the incidence of cell cycle activity increased and myocytes elongated. In the later phase, the incidence of cell cycle activity remained elevated, %binucleation increased, and cross sections were greater. This study highlights unique fetal adaptations of the myocardium and the importance of experimental duration when interpreting fetal cardiac growth data.