bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Sequence-Directed Nucleosome Disruption on Cell-Type-Specific Repression by α2/Mcm1 in the Yeast Genome
Authors: Morohashi Nobuyuki , Yamamoto Yuichi , Kuwana Shunsuke , Morita Wataru , Shindo Heisaburo , Mitchell Aaron P. , Shimizu Mitsuhiro
Published: November 2006

In
Saccharomyces cerevisiae
, a-cell-specific genes are repressed in
MAT
α cells by α2/Mcm1, acting in concert with the Ssn6-Tup1 corepressors and the Isw2 chromatin remodeling complex, and nucleosome positioning has been proposed as one mechanism of repression. However, prior studies showed that nucleosome positioning is not essential for repression by α2/Mcm1 in artificial reporter plasmids, and the importance of the nucleosome positioning remains questionable. We have tested the function of positioned nucleosomes through alteration of genomic chromatin at the
a
-cell-specific gene
BAR1
. We report here that a positioned nucleosome in the
BAR1
promoter is disrupted in
cis
by the insertion of diverse DNA sequences such as poly(dA) · poly(dT) and poly(dC-dG) · poly(dC-dG), leading to inappropriate partial derepression of
BAR1
. Also, we show that
isw2
mutation causes loss of nucleosome positioning in
BAR1
in
MAT
α cells as well as partial disruption of repression. Thus, nucleosome positioning is required for full repression, but loss of nucleosome positioning is not sufficient to relieve repression completely. Even though disruption of nucleosome positioning by the
cis
- and
trans
-acting modulators of chromatin has a modest effect on the level of transcription, it causes significant degradation of the α-mating pheromone in
MAT
α cells, thereby affecting its cell type identity. Our results illustrate a useful paradigm for analysis of chromatin structural effects at genomic loci.
Molecular Characterization of the Minimal Replicon and the Unidirectional Theta Replication of pSCM201 in Extremely Halophilic Archaea
Authors: Sun Chaomin , Zhou Meixian , Li Yun , Xiang Hua
Published: November 2006

A 3,463-bp plasmid, pSCM201, was isolated from a halophilic archaeon,Haloarculasp. strain AS7094. The minimal replicon that is essential and sufficient for autonomous replication and stable maintenance inHaloarcula hispanicawas determined by deletion analysis of the plasmid. This minimal replicon (∼1.8 kb) consisted of only two functionally related segments: (i) a putative origin (ori201) containing an AT-rich region and sets of repeats and (ii) an adjacent gene encoding a putative replication initiation protein (Rep201). Electron microscopic observation and Southern blotting analysis demonstrated that pSCM201 replicates via a theta mechanism. Precise mapping of the putative origin suggested that the replication initiated from a fixed site close to the AT-rich region and proceeded unidirectionally toward the downstreamrep201gene, which was further confirmed by electron microscopic analysis of the ClaI-digested replication intermediates. To our knowledge, this is the first unidirectional theta replication plasmid experimentally identified in the domain of archaea. It provides a novel plasmid system to conduct research on archaeal DNA replication.
Detection of Multidrug Resistance in
Mycobacterium tuberculosis
Authors: Sekiguchi Jun-ichiro , Miyoshi-Akiyama Tohru , Augustynowicz-Kopeć Ewa , Zwolska Zofia , Kirikae Fumiko , Toyota Emiko , Kobayashi Intetsu , Morita Koji , Kudo Koichiro , Kato Seiya , Kuratsuji Tadatoshi , Mori Toru , Kirikae Teruo
Published: November 2006

We developed a DNA sequencing-based method to detect mutations in the genome of drug-resistant
Mycobacterium tuberculosis
. Drug resistance in
M. tuberculosis
is caused by mutations in restricted regions of the genome. Eight genome regions associated with drug resistance, including
rpoB
for rifampin (RIF),
katG
and the
mabA
(
fabG1
)-
inhA
promoter for isoniazid (INH),
embB
for ethambutol (EMB),
pncA
for pyrazinamide (PZA),
rpsL
and
rrs
for streptomycin (STR), and
gyrA
for levofloxacin, were amplified simultaneously by PCR, and the DNA sequences were determined. It took 6.5 h to complete all procedures. Among the 138 clinical isolates tested, 55 were resistant to at least one drug. Thirty-four of 38 INH-resistant isolates (89.5%), 28 of 28 RIF-resistant isolates (100%), 15 of 18 EMB-resistant isolates (83.3%), 18 of 30 STR-resistant isolates (60%), and 17 of 17 PZA-resistant isolates (100%) had mutations related to specific drug resistance. Eighteen of these mutations had not been reported previously. These novel mutations include one in
rpoB
, eight in
katG
, one in the
mabA-inhA
regulatory region, two in
embB
, five in
pncA
, and one in
rrs. Escherichia coli
isolates expressing individually five of the eight
katG
mutations showed loss of catalase and INH oxidation activities, and isolates carrying any of the five
pncA
mutations showed no pyrazinamidase activity, indicating that these mutations are associated with INH and PZA resistance, respectively. Our sequencing-based method was also useful for testing sputa from tuberculosis patients and for screening of mutations in
Mycobacterium bovis
. In conclusion, our new method is useful for rapid detection of multiple-drug-resistant
M. tuberculosis
and for identifying novel mutations in drug-resistant
M. tuberculosis
.
Severe Acute Respiratory Syndrome Coronavirus Protein 6 Accelerates Murine Coronavirus Infections
Authors: Tangudu Chandra , Olivares Heidi , Netland Jason , Perlman Stanley , Gallagher Thomas
Published: November 2006

One or more of the unique 3′-proximal open reading frames (ORFs) of the severe acute respiratory syndrome (SARS) coronavirus may encode determinants of virus virulence. A prime candidate is ORF6, which encodes a 63-amino-acid membrane-associated peptide that can dramatically increase the lethality of an otherwise attenuated JHM strain of murine coronavirus (L. Pewe, H. Zhou, J. Netland, C. Tangudu, H. Olivares, L. Shi, D. Look, T. Gallagher, and S. Perlman, J. Virol. 79:11335-11342, 2005). To discern virulence mechanisms, we compared the in vitro growth properties of rJ.6, a recombinant JHM expressing the SARS peptide, with isogenic rJ.6-KO, which has an inactive ORF containing a mutated initiation codon and a termination codon at internal position 27. The rJ.6 infections proceeded rapidly, secreting progeny about 1.5 h earlier than rJ.6-KO infections did. The rJ.6 infections were also set apart by early viral protein accumulation and by robust expansion via syncytia, a characteristic feature of JHM virus dissemination. We found no evidence for protein 6 operating at the virus entry or assembly stage, as virions from either infection were indistinguishable. Rather, protein 6 appeared to operate by fostering viral RNA and protein synthesis, as RNA quantifications by reverse transcription-quantitative PCR revealed viral RNA levels in the rJ.6 cultures that were five to eight times higher than those lacking protein 6. Furthermore, protein 6 coimmunoprecipitated with viral RNAs and colocalized on cytoplasmic vesicles with replicating viral RNAs. The SARS coronavirus encodes a novel membrane protein 6 that can accelerate replication of a related mouse virus, a property that may explain its ability to increase in vivo virus virulence.
Severe Acute Respiratory Syndrome Coronavirus Infection of Mice Transgenic for the Human Angiotensin-Converting Enzyme 2 Virus Receptor
Authors: Tseng Chien-Te K. , Huang Cheng , Newman Patrick , Wang Nan , Narayanan Krishna , Watts Douglas M. , Makino Shinji , Packard Michelle M. , Zaki Sherif R. , Chan Teh-sheng , Peters Clarence J.
Published: November 2006

Animal models for severe acute respiratory syndrome (SARS) coronavirus infection of humans are needed to elucidate SARS pathogenesis and develop vaccines and antivirals. We developed transgenic mice expressing human angiotensin-converting enzyme 2, a functional receptor for the virus, under the regulation of a global promoter. A transgenic lineage, designated AC70, was among the best characterized against SARS coronavirus infection, showing weight loss and other clinical manifestations before reaching 100% mortality within 8 days after intranasal infection. High virus titers were detected in the lungs and brains of transgene-positive (Tg+) mice on days 1 and 3 after infection. Inflammatory mediators were also detected in these tissues, coinciding with high levels of virus replication. Lower virus titers were also detected in other tissues, including blood. In contrast, infected transgene-negative (Tg−) mice survived without showing any clinical illness. Pathologic examination suggests that the extensive involvement of the central nervous system likely contributed to the death of Tg+mice, even though viral pneumonia was present. Preliminary studies with mice of a second lineage, AC63, in which the transgene expression was considerably less abundant than that in the AC70 line, revealed that virus replication was largely restricted to the lungs but not the brain. Importantly, despite significant weight loss, infected Tg+AC63 mice eventually recovered from the illness without any mortality. The severity of the disease that developed in these transgenic mice—AC70 in particular—makes these mouse models valuable not only for evaluating the efficacy of antivirals and vaccines, but also for studying SARS coronavirus pathogenesis.
Decadal changes in the North Sea food web between 1981 and 1991 — implications for fish stock assessment
Authors: Kempf Alexander , Floeter Jens , Temming Axel
Published: November 2006

The North Sea ecosystem of the early 1980s differed substantially from that of the early 1990s. The current North Sea multispecies fisheries assessment models are parameterized by fish diet data sets that reflect both ecosystem states, as the stomachs were sampled in 1981 and 1991. In this study, multispecies virtual population analysis (MSVPA) was parameterized with either diet data set, leading to different model food webs, each representing the predator's diet selection behavior and spatiotemporal overlap with their prey in the two respective ecosystem states. The impact of these changes in predator preferences and spatiotemporal overlap on recruitment success and on stock developments could be demonstrated by using either stomach data set to estimate historic and future spawning stock biomass and recruitment trajectories. The observed changes in the food web mainly impacted the hindcasted recruitment trajectories, whereas spawning stock biomass estimates were quite robust. In the prediction runs, the differences in the survival rate of the recruits decided whether fish stocks of commercially important species (e.g., Gadus morhua, Merlangius merlangus) would recover or collapse in the near future.
The effect of an adenosine and lidocaine intravenous infusion on myocardial high-energy phosphates and pH during regional ischemia in the rat model in vivo
Authors: Canyon Sarah J. , Dobson Geoffrey P.
Published: November 2006

We have previously shown that an intravenous infusion of adenosine and lidocaine (AL) solution protects against death and severe arrhythmias and reduces infarct size in the in vivo rat model of regional ischemia. The aim of this study was to examine the relative changes of myocardial high-energy phosphates (ATP and PCr) and pH in the left ventricle during ischemia–reperfusion using 31P NMR in AL-treated rats (n = 7) and controls (n = 6). The AL solution (A: 305 μg·(kg body mass)–1·min–1; L: 608 μg·(kg body mass)–1·min–1) was administered intravenously 5 min before and during 30 min coronary artery ligation. Two controls died from ventricular fibrillation; no deaths were recorded in AL-treated rats. In controls that survived, ATP fell to 73% ± 29% of baseline by 30 min ischemia and decreased further to 68% ± 28% during reperfusion followed by a sharp recovery at the end of the reperfusion period. AL-treated rats maintained relatively constant ATP throughout ischemia and reperfusion ranging from 95% ± 6% to 121% ± 10% of baseline. Owing to increased variability in controls, these results were not found to be significant. In contrast, control [PCr] was significantly reduced in controls compared with AL-treated rats during ischemia at 10 min (68% ± 7% vs. 99% ± 6%), at 15 min (68% ± 10% vs. 93% ± 2%), and at 20 min (67% ± 15% vs. 103% ± 5%) and during reperfusion at 10 min (56% ± 22% vs. 99% ± 7%), at 15 min (60% ± 10% vs. 98% ± 7%), and at 35 min (63% ± 14% vs. 120% ± 11%) (p < 0.05). Interestingly, changes in intramyocardial pH between each group were not significantly different during ischemia and fell by about 1 pH unit to 6.6. During reperfusion, pH in AL-treated rats recovered to baseline in 5 min but not in controls, which recovered to only around pH 7.1. There was no significant difference in the heart rate, mean arterial pressure, and rate-pressure product between the controls and AL treatment during ischemia and reperfusion. We conclude that AL cardioprotection appears to be associated with the preservation of myocardial high-energy phosphates, downregulation of the heart at the expense of a high acid-load during ischemia, and with a rapid recovery of myocardial pH during reperfusion.
Effects of triiodo-thyronine on angiotensin-induced cardiomyocyte hypertrophy: reversal of increased β-myosin heavy chain gene expression
Authors: Wang Baohua , Ouyang Jingping , Xia Zhengyuan
Published: November 2006

Thyroid hormone-induced cardiac hypertrophy is similar to that observed in physiological hypertrophy, which is associated with high cardiac contractility and increased α-myosin heavy chain (α-MHC, the high ATPase activity isoform) expression. In contrast, angiotensin II (Ang II) induces an increase in myocardial mass with a compromised contractility accompanied by a shift from α-MHC to the fetal isoform β-MHC (the low ATPase activity isoform), which is considered as a pathological hypertrophy and inevitably leads to the development of heart failure. The present study is designed to assess the effect of thyroid hormone on angiotensin II-induced hypertrophic growth of cardiomyocytes in vitro. Cardiomyocytes were prepared from hearts of neonatal Wistar rats. The effects of Ang II and 3,3′,5-triiodo-thyronine (T3) on incorporations of [3H]-thymine and [3H]-leucine, MHC isoform mRNA expression, PKC activity, and PKC isoform protein expression were studied. Ang II enhanced [3H]-leucine incorporation, β-MHC mRNA expression, PKC activity, and PKCε expression and inhibited α-MHC mRNA expression in cardiomyocytes. T3 treatment prevented Ang II-induced increases in PKC activity, PKCε, and β-MHC mRNA overexpression and favored α-MHC mRNA expression. Thyroid hormone appears to be able to reprogram gene expression in Ang II-induced cardiac hypertrophy, and a PKC signal pathway may be involved in such remodeling process.
Genetic elucidation of host use by individual sympatric bronzed cowbirds (Molothrus aeneus) and brown-headed cowbirds (M. ater)
Authors: Ellison K. , Sealy S.G. , Gibbs H.L.
Published: November 2006

Species of avian brood parasites that use one or several species of hosts are called host specialists and generalists, respectively. To determine host use of individual bronzed cowbirds, Molothrus aeneus (Wagler, 1829), and brown-headed cowbirds, Molothrus ater (Boddaert, 1783), we assigned maternity to eggs using microsatellite DNA markers. We measured patterns of host use by individual sympatric cowbirds. This allowed us to determine whether these species competed for host nests and the number of females laying at nests that were already parasitized by conspecifics. We monitored 1447 nests of 42 potential host species and found that each species of cowbird used primarily four host species, with minimal overlap in the species used, yet at least some individuals acted as generalists. Individual cowbirds tended to avoid laying again at nests each had already parasitized, and multiple parasitism was frequently due to same-day laying by more than one female (19% and 44% of 27 and 39 cases for brown-headed and bronzed cowbirds, respectively). Our results suggest that both cowbirds can differentially parasitize host species; however, host use does not appear to be refined, as many eggs were laid in already-parasitized nests when unparasitized nests of other suitable host species were available.
EQUIVALENCE PROBLEM OF THIRD-ORDER ORDINARY DIFFERENTIAL EQUATIONS
Authors: YOSHIKAWA ATSUKO YAMADA
Published: November 2006

We are concerned with the equivalence problem of third-order ordinary differential equations (ODEs) under bundle diffeomorphisms of three-dimensional real space. For those ODEs, we define canonical structure equations of a bundle on the second jet space, and introduce four torsion parts. We characterize linear third-order ODEs and projective linear third-order ODEs defined on tangent scrolls of space curves by vanishing of some torsion parts.
Polarity Control of ZnO on N-Terminated GaN(0001) Surfaces
Authors: Fujiwara Katsutoshi , Ishii Akira , Ebisuzaki Toshikazu , Abe Tomoki , Ando Koshi
Published: November 2006

We investigated the dynamics of zinc and oxygen adatoms deposited as atomic zinc and atomic oxygen on an N-polarity GaN(0001) surface, and the stability of 1 ML ZnO on an N-polarity GaN(0001) interfacial structure by first-principles calculation. We found that the adatom dynamics on an N-terminated GaN(0001) surface shows Zn polarity. However, we found in our calculated results that the most stable structure for 1 ML ZnO on an N-polarity GaN(0001) interface has O polarity. We found that the key to change the polarity of ZnO crystals grown on the N-terminated GaN(0001) surface is Zn–O interaction. We suggested that the optimal initial growth conditions for the growth of a Zn-polarity ZnO crystal on the N-terminated GaN(0001) surface are suitable low temperature and stoichiometric growth conditions that weaken the effect of Zn–O interaction.
Blue Luminescent Center and Ultraviolet-Emission Dependence of ZnO Films Prepared by Pulsed Laser Deposition
Authors: Wei Xianqi , Man Baoyuan , Xue Chengshan , Chen Chuansong , Liu Mei
Published: November 2006

ZnO thin films were grown on sapphire substrates at a growth temperature of 400 °C by Nd:yttrium–aluminum–garnet (Nd:YAG 1064 nm) pulsed-laser deposition. The effects of oxygen pressure on the structure, stoichiometric composition and optical properties of ZnO thin films were investigated in detail. X-ray diffraction (XRD) shows that the crystal quality is highest for the ZnO film grown at a pressure of 10 mTorr. Optical transmittance, electronic properties and Raman spectra show the increase in the stoichiometric composition ratio of ZnO films with increasing oxygen pressure owing to the reduction in the number of oxygen vacancies (VO) and Zn interstitials (Zni). Photoluminescence (PL) spectra reveal that the UV-emission properties have greater dependence on the stoichiometriy of ZnO films than on the crystal quality. A blue-light emission peak at about 465 nm (Eg=2.66 eV) was observed in the PL spectra of ZnO thin films fabricated at various oxygen pressures. This emission peak was ascribed to the electronic transition from the donor energy level of the Zn interstitials to the acceptor energy level of the Zn vacancies (VZn) rather than the oxygen vacancies.
Fabrication and Characterization of Ferroelectric Gate Field-Effect Transistor Memory Based on Ferroelectric–Insulator Interface Conduction
Authors: Lee Bong Yeon , Minami Takaki , Kanashima Takeshi , Okuyama Masanori
Published: November 2006

A new type of ferroelectric gate field-effect transistor (FET) using ferroelectric–insulator interface conduction has been proposed. Drain current flows along the interface between the ferroelectric and insulator layers and requires no semiconductor. The channel region of the FET is composed of a Pt/insulator HfO2/ferroelectric Pb(Zr0.52Ti0.48)O3 (PZT)/Pt/TiO2/SiO2/Si multilayer, and the source and drain areas are formed at the interface of the PZT and HfO2 films. Drain current versus gate voltage characteristics show a clockwise hysteresis loop similar to that for a conventional p-channel transistor. The FET shows that the on/off ratio of the conduction current is within 105 to 106 and that the off-state current is about 10-10 A.
Stability of (1100) m-Plane GaN Films Grown by Metalorganic Chemical Vapor Deposition
Authors: Imer Bilge , Wu Feng , Craven Michael D. , Speck James S. , DenBaars Steven P.
Published: November 2006

We show the stability of planar nonpolar (1100) m-plane GaN thin films grown on m-plane 6H–SiC substrates using an AlN nucleation layer (NL) by metalorganic chemical vapor deposition (MOCVD). The stability of the m-plane GaN films was studied for a wide range of growth variables including reactor pressure, temperature, and group III and V flow rates. The surface morphology and crystal quality of the m-plane GaN films were less sensitive to changes in these growth variables than those of nonpolar (1120) a-plane heteroepitaxial planar GaN films. The threading dislocation density of m-GaN on m-plane 6H–SiC was one order of magnitude lower than that of a-GaN on a-plane 6H–SiC.
High-κ Material Sidewall with Source/Drain-to-Gate Non-overlapped Structure for Low Standby Power Applications
Authors: Ma Ming-Wen , Chao Tien-Sheng , Kao Kuo-Hsing , Huang Jyun-Siang , Lei Tan-Fu
Published: November 2006

In this paper, fully depleted silicon-on-insulator (SOI) devices with source/drain extension shifts and a high-κ offset spacers were investigated in detail. The calculated results show that the source/drain extension shift can decrease off-state leakage current I
off significantly by utilizing the extra electron barrier height in the source/drain extension shift region to reduce standby power dissipation. However, the on-state driving current I
on is also sacrificed simultaneously. To overcome this drawback, a high-κ offset spacer is used to increase the on-state driving current I
on effectively by enhancing the vertical fringing electric field which elevates the channel voltage drop and reduces series resistance.
Equation for Internal Quantum Efficiency and Its Temperature Dependence of Luminescence, and Application to InxGa1-xN/GaN Multiple Quantum Wells
Authors: Sasaki Akio , Shibakawa Shin-ichiro , Kawakami Yoichi , Nishizuka Kohji , Narukawa Yukio , Mukai Takashi
Published: November 2006

We derive the equation for the internal quantum efficiency (IQE) and its temperature dependence of luminescence. In general, time-resolved photoluminescence (TRPL) must be carried out by changing temperature to obtain the efficiency and the dependence; however, they can be obtained by fitting the equation derived in this study to the temperature characteristics of luminescence integrated intensity. Thus, they are obtained without carrying out TRPL experiments. The equation is applicable to the characteristics not restricted by the measurement method. It is also applied to any semiconductor whose luminescence integrated intensity decreases with increasing temperature. In this study, the equation is applied to the luminescence characteristics of In
x
Ga1-x
N/GaN multiple quantum wells. These luminescence characteristics are analyzed in terms of the IQE and the temperature dependence derived using the equation and interpreted in connection with In composition fluctuations, strain effects, and interface quality.
Analysis of Ferroelectric Microcapacitors at Low and High Temperatures Using a Scanning Probe Microscope
Authors: Kin Nobuhiro , Honda Koichiro
Published: November 2006

It is widely recognized that, in ferroelectric bulk or thin films, the coercive voltage (V
c) increases at low temperatures and the remnant polarization (P
r) decreases at high temperatures. With the ongoing integration of ferroelectric random-access memory (FeRAM), the size of these capacitors has fallen to about 1.5 µm2, making it necessary to know whether such ferroelectric microcapacitors have the same nature and behave in the same manner as bulk or thin films at low and high temperatures, or if they do not behave as expected owing to so-called size effects or for some other reason. To further evaluate the impact of temperature on ferroelectrics, we have devised a new evaluation system, based on a scanning probe microscope, which can measure the electrical characteristics of a single-bit cell capacitor at temperatures between -60 and 120 °C. The electrical properties are measured using a sample with an IrO
x
/Pb(Zr,Ti)O3/Pt structure. It has been shown that both V
c and P
r actually increase at low temperatures in FeRAM single-bit cell capacitors.
Effect of B2O3 Addition to La(Co1/2Ti1/2)O3 Ceramics on Sintering Behavior and Microwave Dielectric Properties
Authors: Tseng Ching-Fang , Huang Cheng-Liang
Published: November 2006

Sintering behaviors and microstructural characteristics of La(Co1/2Ti1/2)O3 ceramics were investigated. The La(Co1/2Ti1/2)O3 ceramics were prepared by the conventional solid-state route. Doping with B2O3 (up to 0.75 wt %) can effectively promote the densification of La(Co1/2Ti1/2)O3 ceramics at a low sintering temperature. With B2O3 addition, the sintering temperature of La(Co1/2Ti1/2)O3 can be effectively reduced from 1440 to 1230–1350 °C. At 1350 °C/6 h, La(Co1/2Ti1/2)O3 ceramic with 0.25 wt % B2O3 addition possesses a dielectric constant (ε
r) of 30, a Q×f value of 64,600 GHz (at 8 GHz) and a temperature coefficient of resonant frequency (τf) of -48 ppm/°C. The B2O3-doped La(Co1/2Ti1/2)O3 ceramic is applicable in microwave devices requiring low sintering temperature.
Electron Spin Resonance Investigations and Compensation Mechanism of Europium-Doped Barium Titanate Ceramics
Authors: Lu Da-Yong , Sun Xiu-Yun , Toda Masayuki
Published: November 2006

The electron spin resonance (ESR) technique was employed to investigate the point defects and evidence of Eu2+ in Eu-doped barium titanate (EBT) ceramics sintered in air according to the formula (Ba1-x
Eu
x
)Ti1-x/8O3. The charge equilibrium compensation mechanism was discussed on the basis of ESR with the aid of X-ray diffraction (XRD) and differential scanning calorimetric (DSC) techniques. Eu is incorporated into Ba sites of BaTiO3 as Eu3+ up to x=0.02 and as mixed Eu2+/Eu3+ at x=0.03, which is evidenced by Eu3+-induced Ti-vacancy defects with g=2.004 and a broad Eu2+ signal with g=1.98, and a single-phase tetragonal perovskite structure can be retained. When x≥0.04, it is concluded that high density and low porosity in highly insulating and fine-grained EBT ceramics originate from the coexistence of mixed Eu2+/Eu3+; in particular, the increase in the proportion of Eu2+ in the perovskite phase increases ceramic density, but is accompanied by emergence of the Eu2Ti2O7 phase.
Development of Transient Measurement Method for investigating Thermoelectric Properties in High Temperature Region
Authors: Fujimoto Shinichi , Kaibe Hiromasa , Sano Seijirou , Kajitani Tsuyoshi
Published: November 2006

The measurement equipment based on a transient measurement method was fabricated to characterize Seebeck coefficient, resistivity, and thermal conductivity simultaneously from room temperature to 573 K. The rate of ambient heat flow was reduced by employing a thermal anchor and a thermal reflector at elevated temperatures, and a model for suitable corrections for compensating remaining errors in data evaluation was studied. Using n-type Bi2Te3-based samples, the comparison of thermoelectric properties with the results obtained using another commercial conventional measurement equipment was performed and showed a very good agreement.
Modeling of Feature Profile Evolution in SiO2 as functions of Radial Position and Bias Voltage under Competition among Charging, Deposition, and Etching in Two-Frequency Capacitively Coupled Plasma
Authors: Shimada Takashi , Yagisawa Takashi , Makabe Toshiaki
Published: November 2006

A feature profile evolution model of a trench in SiO2 is developed in a two-frequency capacitively coupled plasma in CF4(5%)/Ar by considering two layers, a mixing layer and an overlaying polymer layer on the basis of a database of etching yield by extending our original physical computer-aided design (CAD) tool, VicAddress (vertically integrated computer-aided design for device processes). That is, the surface exposed to fluorocarbon plasma is considered under competition among the charging of electrons and ions, the deposition of radicals, and reactive etching by ions. The feature profile is also discussed in terms of the bias amplitude and the position on the wafer.
CuOx Films as Anodes for Organic Light-Emitting Devices
Authors: Wang Shuai , Osasa Takahiro , Matsumura Michio
Published: November 2006

CuO
x
films were prepared on glass plates by the vacuum sublimation of Cu films followed by an oxygen-plasma treatment. These CuO
x
films showed a strong hole-injection ability and found to be applicable to organic light-emitting devices as anodes, although their optical transmittance and conductivity were slightly lower than those of indium–tin-oxide layers. The most important merit of employing the films as the anodes lies in that they are easily shaped in patterns by vacuum sublimation using shadow masks in device fabrication.
Full-Field Optical Coherence Tomography System with Controllable Longitudinal Resolution
Authors: Nitta Kouichi , Li Tingyu , Motoyama Toshiki , Matoba Osamu , Yoshimura Takeaki
Published: November 2006

A full-field optical coherence tomography (OCT) system that can control longitudinal resolution is presented. The system is based on the synthesis of the optical coherence function from the wavelength scanning of laser light within a frame time of an imaging device. On the basis of the results of our experiments, it is confirmed that our system can select any longitudinal resolution between 6–120 µm and that this performance is available for practical use such as for the tomographic imaging of various sizes of targets in a scattering medium.
Chromeless Phase Lithography Using Scattering Bars and Zebra Patterns
Authors: Kang Hye-Young , An Ilsin , Shin Dong-Soo , Jeong HeeJun , Ahn Chang-Nam , Oh Hye-Keun
Published: November 2006

Resolution enhancement technology refers to a technique that extends the usable resolution of an imaging system without decreasing the wavelength of light or increasing the numerical aperture (NA) of the imaging tool. Off-axis illumination and a phase shift mask (PSM) are essentially accompanied by optical proximity correction (OPC) for most devices nowadays. Chromeless phase lithography (CPL) is one of the PSM technologies. To obtain the best resolution, proper OPC is required with CPL. While the most common application of OPC is to provide mask bias, an additional technique is the use of scattering bars (SBs) and zebra patterns. We compared zebra patterns for 65 nm lines and spaces (L/S) and 45 nm isolated line (I/L) with SBs. To optimize zebra pattern density, we vary the line width and pitch of the zebra patterns. We confirmed that the use of SB and zebra patterns could realize the target linewidth and control necessary for acheiving dense L/S and I/L.
How Prior Reward Experience Biases Exploratory Movements: A Probabilistic Model
Authors: German Paul W. , Fields Howard L.
Published: November 2006

Animals return to rewarded locations. An example of this is conditioned place preference (CPP), which is widely used in studies of drug reward. Although CPP is expressed as increased time spent in a previously rewarded location, the behavioral strategy underlying this change is unknown. We continuously monitored rats ( n = 22) in a three-room in-line configuration, before and after morphine conditioning in one end room. Although sequential room visit durations were variable, their probability distribution was exponential, indicating that the processes controlling visit durations can be modeled by instantaneous room exit probabilities. Further analysis of room transitions and computer simulations of probabilistic models revealed that the exploratory bias toward the morphine room is best explained by an increase in the probability of a subset of rapid, direct transitions from the saline- to the morphine-paired room by the central room. This finding sharply delineates and constrains possible neural mechanisms for a class of self-initiated, goal-directed behaviors toward previously rewarded locations.
Topological Determinants of Epileptogenesis in Large-Scale Structural and Functional Models of the Dentate Gyrus Derived From Experimental Data
Authors: Dyhrfjeld-Johnsen Jonas , Santhakumar Vijayalakshmi , Morgan Robert J. , Huerta Ramon , Tsimring Lev , Soltesz Ivan
Published: November 2006

In temporal lobe epilepsy, changes in synaptic and intrinsic properties occur on a background of altered network architecture resulting from cell loss and axonal sprouting. Although modeling studies using idealized networks indicated the general importance of network topology in epilepsy, it is unknown whether structural changes that actually take place during epileptogenesis result in hyperexcitability. To answer this question, we built a 1:1 scale structural model of the rat dentate gyrus from published in vivo and in vitro cell type–specific connectivity data. This virtual dentate gyrus in control condition displayed globally and locally well connected (“small world”) architecture. The average number of synapses between any two neurons in this network of over one million cells was less than three, similar to that measured for the orders of magnitude smaller C. elegans nervous system. To study how network architecture changes during epileptogenesis, long-distance projecting hilar cells were gradually removed in the structural model, causing massive reductions in the number of total connections. However, as long as even a few hilar cells survived, global connectivity in the network was effectively maintained and, as a result of the spatially restricted sprouting of granule cell axons, local connectivity increased. Simulations of activity in a functional dentate network model, consisting of over 50,000 multicompartmental single-cell models of major glutamatergic and GABAergic cell types, revealed that the survival of even a small fraction of hilar cells was enough to sustain networkwide hyperexcitability. These data indicate new roles for fractionally surviving long-distance projecting hilar cells observed in specimens from epilepsy patients.
Glycine Binding Sites of Presynaptic NMDA Receptors May Tonically Regulate Glutamate Release in the Rat Visual Cortex
Authors: Li Yan-Hai , Han Tai-Zhen
Published: November 2006

In the CNS, activation of N-methyl-d-aspartate receptor (NMDA-R) glycine binding sites is a prerequisite for activation of postsynaptic NMDA-Rs by the excitatory neurotransmitter glutamate. Here we provide electrophysiological evidence that the glycine binding sites of presynaptic NMDA-Rs regulate glutamate release in layer II/III pyramidal neurons of the rat visual cortex. Specifically, our results reveal that the frequency of miniature excitatory postsynaptic currents is significantly reduced by 7-chloro-kynurenic acid (7-Cl KYNA), a NMDA-R glycine binding site antagonist, and glycine or d-serine reverses this effect. Similar results are obtained when the open-channel NMDA receptor blocker, MK-801, is included in the recording pipette. Our data indicate that the glycine binding site of postsynaptic NMDA-Rs is not saturated. Moreover, they suggest that presynaptic NMDA-Rs are located in layer II/III pyramidal neurons of the rat visual cortex and that the glycine binding site of presynaptic NMDA-Rs tonically regulates glutamate release.
Conserved expression of alternative splicing variants of peroxisomalacyl-CoA oxidase 1in vertebrates and developmental and nutritional regulation in fish
Authors: Morais Sofia , Knoll-Gellida Anja , André Michèle , Barthe Christophe , Babin Patrick J.
Published: November 2006

The acyl-coenzyme A oxidase 1 (ACOX1) catalyzes the first, rate-limiting step in peroxisomal β-oxidation of medium to very long straight-chain fatty acids. Zebrafish ( Danio rerio) acox1 was characterized and compared with homologs from other sequenced genomes, revealing a remarkable conservation of structure in the vertebrate lineage. Strictly conserved regions of the deduced proteins included acyl-CoA oxidase and FAD binding domains, as well as a COOH-terminal peroxisomal targeting signal. Whole mount in situ hybridization showed that zebrafish acox1 transcripts were diffusely distributed in early-stage embryonic cells, then discreetly expressed in the brain and widely present in the liver and intestine at later stages. An evolutionarily conserved alternative splicing of the corresponding acox1 primary transcript was identified in teleosts and tetrapods including mammals, giving rise, after exon skipping, to two splice variants, ACOX1–3I and ACOX1–3II. Real-time quantitative RT-PCR on zebrafish adult tissues indicated high levels of both variants in the liver, anterior intestine, and to a lesser extent, in the brain. However, the ACOX1–3II transcript variant was expressed seven times more in zebrafish brain than the ACOX1–3I variant. These data suggest a tissue-specific modulation of ACOX1 activity by exchanging exon 3 duplicated isoforms containing amino acid sequences that are potentially implicated in fatty acyl chain specificity. In addition, a significant pretranslational up-regulation of zebrafish and rainbow trout ( Oncorhynchus mykiss) acox1 expression was observed in the anterior intestine after feeding. Taken together, these data indicate that ACOX1 alternative splicing isoforms play a key conserved role in the vertebrate fatty acid metabolism.
On a fixed point theorem of Krasnosel'skii type and application to integral equations
Authors: Ngoc Le Thi Phuong , Long Nguyen Thanh
Published: November 2006

This paper presents a remark on a fixed point theorem of Krasnosel'skii type. This result is applied to prove the existence of asymptotically stable solutions of nonlinear integral equations.
Underuse of Standard Care and Outcome of Patients with Acute Myocardial Infarction and Chronic Renal Insufficiency
Authors: Tessone Ariel , Gottlieb Shmuel , Barbash Israel M. , Garty Moshe , Porath Avi , Tenenbaum Alexander , Hod Hanoch , Boyko Valentina , Mandelzweig Lori , Behar Solomon , Leor Jonathan
Published: November 2006

Objectives: To investigate characteristics, management and outcome of patients with acute myocardial infarction (AMI) and chronic renal insufficiency (CRI). Background: Patients with AMI and CRI are considered to be at high risk of complications and death. Physicians may be reluctant to prescribe life-saving medications to patients with concomitant CRI. Methods: We compared clinical characteristics, management and outcome of 1,683 consecutive AMI patients in three categories of renal function: (1) normal renal function (<1.5 mg/dl) (n = 1,559), (2) mild to moderate CRI (1.5– 3.5 mg/dl) (n = 77), and (3) severe CRI (>3.5 mg/dl) (n = 47). Results: CRI patients were older and were more likely to have other co-morbidities such as hypertension, diabetes mellitus, prior AMI, stroke, angina and heart failure. Compared with patients with normal renal function, standard therapy for AMI including thrombolysis, aspirin, angiotensin-converting-enzyme inhibitors, β-blockers and lipid lowering agents was underutilized in CRI patients and these patients were more likely to have in-hospital complications such as heart failure, atrial or ventricular fibrillation, cardiogenic shock, sepsis, worsening of renal function and death within 30 days [odds ratio (OR) = 3.3; 95% confidence interval (CI) = 2.0–4.8]. After adjustment for age and co-morbidities, the association between mild to moderate CRI and 30-days mortality declined, whereas severe CRI remained an independent determinant of mortality (OR = 4.8; 95% CI = 2.0–11.4). Adjustment for aspirin, angiotensin-converting-enzyme inhibitors and β-blocker therapy weakened the association between CRI and death within 30 days after AMI. Conclusions: CRI patients are more likely to experience serious complications and death early after AMI. Underutilization of standard care, particularly β-blocker therapy, contributes to increased mortality risk in these patients.
The Relationship between Transmural Extent of Infarction on Contrast Enhanced Magnetic Resonance Imaging and Recovery of Contractile Function in Patients with First Myocardial Infarction Treated with Thrombolysis
Authors: Barclay Justin L. , Egred Mohaned , Kruszewski Kirsten , Nandakumar Ramasami , Norton Murdoch Y. , Stirrat Colin , Redpath Thomas W. , Walton Stephen , Hillis Graham S.
Published: November 2006

Background: The aim of the current study was to assess the utility of transmurality of delayed enhancement on cardiac magnetic resonance imaging (MRI) in predicting functional recovery in patients with first ST-elevation myocardial infarction (MI) who had received thrombolysis. Methods: Nineteen patients underwent cine and contrast-enhanced MRI 3 days and 8 weeks after MI. The transmural extent of infarction (TEI) was determined from the late enhancement component of the first scan. Segmental wall thickening was scored from the cine components of both the initial and follow-up scans. Results: The TEI was inversely related to the likelihood of improvement in wall thickening; χ2 test for trend = 53.9, p < 0.0001. Delayed enhancement with >50% transmurality predicted a lack of recovery with 82% sensitivity and 54% specificity. The equivalent values for >75% transmurality were 57 and 77%, respectively. The proportion of the left ventricular segments exhibiting functional recovery was related to the percentage of the left ventricle that was severely dysfunctional but had ≤50% TEI (r = 0.49, p = 0.03). In a backward conditional regression model this was the only independent predictor. Conclusion: These data suggest that TEI, determined by contrast-enhanced cardiac MRI, is a useful predictor of the likelihood, or otherwise, of functional recovery following acute MI treated with thrombolysis.
Toward Maturation of the Vestibular System: Neural Circuits and Neuronal Properties
Authors: Lai Chun-Hong , Tse Yiu-Chung , Shum Daisy Kwok-Yan , Chan Ying-Shing
Published: November 2006

This review focuses on efforts to unravel conundrums on the development of the vestibular system. In the first section, maturation of the peripheral vestibular system and the involvement of transcription factors in the patterning of peripheral vestibular components are highlighted. Cell surface and matrix molecules have also been implicated in fasciculation and guidance of axons in the course of vestibular circuit formation. In rodents, the central vestibular neurons continue to develop after birth until they reach maturity in morphology and function. Sequential maturation of neuronal subpopulations within the developing network of the horizontal and vertical otolith systems is also presented. In another section, the expression pattern of glutamate receptor subunits within the developing vestibular nuclear complex is reviewed in relation to their potential role in regulating postnatal function of the vestibular system. Lastly, postnatal changes in the properties of vestibular nuclear neurons and their capability in coding head movement information appear to prime the development of vestibular-related motor functions.
Relative Capability and Rebel Objective in Civil War
Authors: Buhaug Halvard
Published: November 2006

When all else fails, aggrieved groups of society often resort to violence to redress their grievance - either by seeking to overthrow the ruling government or by attempting to secede. The strength of the rebel group relative to the state determines what direction the conflict will take. In institutionally and economically capable countries, any opposition group is likely to be inferior to the government. These groups will see secession as the most viable strategy to improve living conditions. Inconsistent, poor, and resource-dependent regimes are typically quite unstable and should therefore be more likely to attract coups and revolutions. In addition, large and ethnically diverse countries contain a higher number of peripheral and possibly marginalized groups, as well as remote and inaccessible terrain, both of which are expected to favor secessionist insurgency. Smaller countries, in contrast, offer few opportunities for separatist claims but, in such countries, capturing the state might also be a more realistic objective. This article provides a first test of these presumptions by estimating the effect of several popular explanatory factors separately on the risk of territorial and governmental conflict, 1946-99. The analysis offers considerable support and demonstrates that territorial and governmental conflicts are shaped, in large part, by different causal mechanisms. The reputed parabolic relationship between democracy and risk of civil war only pertains to state-centered conflicts, whereas democracy has a positive and near-linear effect on the risk of territorial rebellion. Moreover, the analysis strongly suggests that the puzzling no-finding of ethnicity in several prominent studies is affected by their inability to account for rebel objective in civil war.
Surveying a Chicago Public Housing Development
Authors: Holbrook Allyson L. , Farrar Isabel C. , Popkin Susan J.
Published: November 2006

During the winter and spring of 2003, the Survey Research Laboratory conducted a survey of residents of the Ida Wells and Madden Park housing developments on Chicago's near-south side. This article reviews existing research findings on using indigenous interviewers and reports the findings about the benefits and challenges of using residents as interviewers versus drawing from a regular pool of interviewers. Specifically, the authors talk abthe challenges faced in using indigenous interviewers and then look at some data quality indicators among these two groups of interviewers, including cooperation rates, item nonresponse, and differences in responses to sensitive questions.
‘Dogs Are “Registered”, People Shouldn’t Be’: Legal Consciousness and Lesbian and Gay Rights
Authors: Harding Rosie
Published: November 2006

In this article I examine lesbians’ and gay men’s attitudes towards the legal recognition of same-sex relationships, using the theoretical framework of legal consciousness. I first provide a brief overview of the legal consciousness literature, before outlining some of the critiques of legal consciousness. Lesbian and gay legal consciousness is then examined through an analysis of qualitative responses to a large-scale online study of perceptions of and attitudes towards same-sex marriage and the legal recognition or regulation of same-sex relationships. Responses are analysed using thematic analysis to elaborate on five main themes within these data: formal equality, the relationship between legal and social change, the naming of legally recognized same-sex relationships, human rights discourse and citizenship claims. I argue that legal consciousness studies can help to interrogate the pervasiveness of discourses around formal equality and discrimination in the ways in which lesbians and gay men think about, use and position themselves in relation to law.
Traveling Beyond Dangerous Private and Universal Discourses
Authors: Eryaman Mustafa Yunus
Published: November 2006

In this article, the author explores several definitions of reading and evaluating educational research texts without finding deep private meanings or developing objective, scientific, and instrumental norms for evaluating quality of educational research studies. Among these descriptions, the author emphasizes Gadamer's weak poststructural model and Habermas's critique of and contribution to it, aiming to replace the neoconservative objectivist and neoliberal subjectivist traditions with something of greater social and intellectual utility: a “dialectical and critical” theory of reading and evaluation of educational research. This alternative approach, based on philosophical hermeneutics, critical theory, and practical philosophy, identifies understanding, interpreting, and evaluating a research text as a political, ideological, ethical, critical, gendered, sexual, racial, transformative, social, discursive, deliberative, and performed experience. The author argues that knowledge developed from this alternative approach represents a step toward the development of transformative political practices and progressive institutions to challenge the neoconservative status quo at intellectual, political, and practical levels.