bluuebunny/crossref_metadata_2025 huggingface dataset:
Integrons and Transposons on the
Salmonella
enterica
Serovar Typhimurium Virulence Plasmid
Authors: Villa Laura , Carattoli Alessandra
Published: February 2005

A virulence plasmid was identified in a multidrug-resistant
Salmonella
enterica
serotype Typhimurium strain carrying the
spvC
,
rck
, and
pefA
virulence genes and two class 1 integrons linked to the Tn
21
and Tn
1696
transposons. A novel trimethoprim resistance gene, designated
dfrA23
, was also identified within the integron region. The association of multidrug resistance and virulence determinants represents an interesting example of virulence plasmid evolution.
International Clone of
Neisseria
meningitidis
Serogroup A with Tetracycline Resistance Due to
tet
(B)
Authors: Crawford Sharon A. , Fiebelkorn Kristin R. , Patterson Jan E. , Jorgensen James H.
Published: February 2005

Thirteen
Neisseria
meningitidis
clinical isolates from Africa, Asia, and the United States for which the tetracycline MICs were elevated (≥8 μg/ml) were examined for 14 recognized resistance genes. Only the drug efflux mechanism encoded by
tet
(B) was detected. All isolates were in serogroup A, belonged to complex ST-5, and were closely related by pulsed-field gel electrophoresis analysis.
New Integron-Associated Gene Cassette Encoding a 3-
N
-Aminoglycoside Acetyltransferase
Authors: Levings Renee S. , Partridge Sally R. , Lightfoot Diane , Hall Ruth M. , Djordjevic Steven P.
Published: February 2005

A fifth gene cassette containing an
aacC
gene,
aacCA5
, was found in an
aacCA5-aadA7
cassette array in a class 1 integron isolated from a multiply drug resistant
Salmonella enterica
serovar Kentucky strain. The AacC-A5 or AAC(3)-Ie acetyltransferase encoded by
aacCA5
is related to other AAC(3)-I enzymes and confers resistance to gentamicin.
Monitoring and Characterization of Extended-Spectrum β-Lactamases in
Escherichia coli
Strains from Healthy and Sick Animals in Spain in 2003
Authors: Briñas Laura , Moreno Miguel Angel , Teshager Tirushet , Sáenz Yolanda , Porrero María Concepción , Domínguez Lucas , Torres Carmen
Published: February 2005

Genes encoding CTX-M-14, CTX-M-9, CTX-M-1, CTX-M-32, SHV-12, TEM-52, or CMY-2 β-lactamases were detected in 21
Escherichia coli
strains recovered during 2003 from sick animals (11 of 459 [2.4%] strains) and healthy animals (10 of 158 [6.3%] strains) in Spain. Twelve of these strains harbored
bla
CTX-M
genes and showed unrelated pulsed-field gel electrophoresis patterns.
Evaluation of Ceftobiprole in a Rabbit Model of Aortic Valve Endocarditis Due to Methicillin-Resistant and Vancomycin-Intermediate
Staphylococcus aureus
Authors: Chambers Henry F.
Published: February 2005

Ceftobiprole is a novel broad-spectrum cephalosporin that binds with high affinity to PBP 2a, the methicillin-resistance determinant of staphylococci, and is active against methicillin- and vancomycin-resistant
Staphylococcus aureus
. Ceftobiprole was compared to vancomycin in a rabbit model of methicillin-resistant
S
.
aureus
aortic valve endocarditis. Ceftobiprole and vancomycin were equally effective against endocarditis caused by methicillin-resistant
S
.
aureus
strain 76, whereas ceftobiprole was more effective than vancomycin against the vancomycin-intermediate
S
.
aureus
strain HIP5836. The activity of ceftobiprole against drug-resistant strains of
S
.
aureus
warrants its further clinical development.
Single-Dose Pharmacokinetics and Metabolism of [
14
C]Remofovir in Rats and Cynomolgus Monkeys
Authors: Lin Chin-Chung , Xu Christine , Zhu Nanqun , Lourenco David , Yeh Li-Tain
Published: February 2005

Single-dose pharmacokinetics and metabolism of [
14
C]remofovir was studied in rats and monkeys following intravenous (i.v.) and oral administration (30 mg/kg of body weight). Oral absorption and bioavailability were 29.7 and 5.42% in rats and 65.6 and 19.4% in monkeys, respectively. Following i.v. administration, the elimination half-life for remofovir was 0.7 h in both rats and monkeys. Total body clearance was 5.85 liters/h/kg in rats and 2.60 liters/h/kg in monkeys; apparent volume of distribution was 5.99 liters/kg in rats and 2.70 liters/kg in monkeys. Following oral administration, remofovir was extensively converted to 9-(2-phosphonylmethoxyethyl)adenine (PMEA) and other metabolites in both species. In rats, excretion of total radioactivity in urine accounted for 61.8% of the i.v. dose and 12.9% of the oral dose, while in monkeys it accounted for 43.3% of the i.v. dose and 34.9% of the oral dose. Following i.v. dosing of [
14
C]remofovir, fecal excretion of radioactivity accounted for 37.5% of the dose in rats and 17.4% of the dose in monkeys, indicating significant biliary excretion of the drug in animals. PMEA and metabolite A were the major urinary metabolites in both species after i.v. and oral administration of remofovir.
Molecular Analysis of Resistance to Streptogramin A Compounds Conferred by the Vga Proteins of Staphylococci
Authors: Chesneau Olivier , Ligeret Heidi , Hosan-Aghaie Negin , Morvan Anne , Dassa Elie
Published: February 2005

The Vga and Msr resistance determinants, encoded by mobile genetic elements in various staphylococcal strains, belong to a family of ATP-binding cassette (ABC) proteins whose functions and structures are ill defined. Their amino acid sequences are similar to those of proteins involved in the immunity of streptomycetes to the macrolide-lincosamide-streptogramin antibiotics that they produce. Sequence analysis of the genomes of the gram-positive bacteria with low G+C contents revealed that Lmo0919 from
Listeria monocytogenes
is more closely related to Vga variants than to Msr variants. In the present study we compared the antibiotic resistance profiles conferred by the Vga-like proteins in two staphylococcal hosts. It was shown that Vga(A), the Vga(A) variant [Vga(A)v], and Lmo0919 can confer resistance to lincosamides and streptogramin A compounds, while only Vga(B) is able to increase the level of resistance to pristinamycin, a mixture of streptogramin A and streptogramin B compounds. By using polyclonal antibodies, we found that the Vga(A) protein colocalized with the β subunit of the F
1
-F
0
ATPase in the membrane fractions of staphylococcal cells. In order to identify functional units in these atypical ABC proteins, such as regions that might be involved in substrate specificity and/or membrane targeting, we analyzed the resistance phenotypes conferred by various plasmids carrying parts or modified versions of the
vga
(A) gene and we determined the subcellular localization of the gene products. Only polypeptides composed of two ABC domains were detected in the cell membranes. No region of drug specificity was identified. Resistance properties were dependent on the integrities of both Walker B motifs.
Physical activity levels during phase IV cardiac rehabilitation in a group of male myocardial infarction patients
Authors: Woolf-May K , Bird S
Published: February 2005

Objective:To determine physical activity levels during phase IV cardiac rehabilitation in 31 male myocardial infarction patients (median age 62, range 53–77 years).

Methods:Patients recorded daily physical activity over 16 weeks in a diary. Diaries were analysed for total general physical activity (TGPA), leisure time physical activity (LTPA), and “active for life” exercise classes (AFL). Pre- and post-observation period (OP) subjects underwent a 10 m shuttle walking test (SWT) to determine changes in aerobic fitness. Rate of perceived exertion (RPE) determined exercise intensity. Estimated gross energy expenditure (EEE) was determined by a regression equation between RPE and Vo2(l min−1) during SWT. A total of 97% of subjects were on lipid lowering medication.

Results:There were no correlations between Vo2(l min−1) and body mass, therefore kcal min−1indicated activity intensity. There were no significant changes in physical activity patterns or in aerobic fitness. Estimated total LTPA (median 1376, range 128–3380 kcal week−1) was less than that recommended to improve aerobic fitness and/or slow progression of coronary artery disease. Sixteen subjects attended a median of 29 (range 1–46) AFL during LTPA; one way ANOVA showed these subjects worked at greater EEE (AFL, n = 16, 6.6 (standard deviation 1.4)vno-AFL, n = 15, 5.1 (1.8) EEE kcal min−1, p = 0.017).

Conclusion:Physical activity was stable, but patients’ EEE appeared insufficient to improve aerobic fitness or slow progression of coronary artery disease. It was suggested that the promotion of LTPA and the availability of AFL classes should be reconsidered.
Molecular characterization and chromosomal localization of female-specific genes from the Mediterranean fruit flyCeratitis capitata(Diptera: Tephritidae)
Authors: Ciolfi Silvia , de Filippis Tiziana , Torti Cristina , Malacrida Anna R , Dallai Romano
Published: February 2005

We report here the molecular characterization of the female-specific FST (female-specific transcript) genes from the Mediterranean fruit fly (medfly) Ceratitis capitata. A genomic clone was isolated, containing a sequence coding for FST. Nucleotide analysis of the clone showed that the gene contains a putative unique intron located in the region encoding the signal peptide. Southern blotting and in situ hybridization analysis on polytene chromosomes suggested the presence of additional genes similar to FST in the genome of the medfly. A novel cDNA clone was isolated from an accessory gland cDNA library, encoding a product that shares 98% identity with the hypothetical translational product of the previously isolated FST cDNA. The novel cDNA was therefore named FST2. The analysis of mitotic and polytene chromosomes by in situ hybridization showed that FST genes map on the left arm of the 4th chromosome of C. capitata.Key words: FST, female-specific genes, C. capitata, medfly, FISH.
The genomic composition of Tricepiro, a synthetic forage crop
Authors: Ferrari María Rosa , Greizerstein Eduardo J , Paccapelo Héctor A , Naranjo Carlos A , Cuadrado Angelines , Jouve Nicolás , Poggio Lidia
Published: February 2005

Chromosome in situ hybridization (FISH and GISH) is a powerful tool for determining the chromosomal location of specific sequences and for analysing genome organization and evolution. Tricepiro (2n = 6x = 42) is a synthetic cereal obtained by G. Covas in Argentina (1972), which crosses hexaploid triticale (2n = 6x = 42) and octoploid Trigopiro (2n = 8x = 56). Several years of breeding produced a forage crop with valuable characteristics from Secale, Triticum, and Thinopyrum. The aim of this work is to analyse the real genomic constitution of this important synthetic crop. In situ hybridization using total DNA of Secale, Triticum, and Thinopyrum as a probe (GISH) labelled with biotin and (or) digoxigenin showed that tricepiro is composed of 14 rye chromosomes and 28 wheat chromosomes. Small zones of introgression of Thinopyrum on wheat chromosomes were detected. The FISH using the rye repetitive DNA probe pSc 119.2 labelled with biotin let us characterize the seven pairs of rye chromosomes. Moreover, several wheat chromosomes belonging to A and B genomes were distinguished. Therefore, tricepiro is a synthetic hexaploid (2n = 6x = 42) being AABBRR in its genomic composition, with zones of introgression of Thinopyrum in the A genome of wheat.Key words: tricepiro, trihybrid, Triticum, Secale, Thinopyrum, in situ hybridization, FISH, GISH, genomic composition, synthetic forage crop.
A new intervarietal linkage map and its application for quantitative trait locus analysis of "gigas" features in bread wheat
Authors: Suenaga Kazuhiro , Khairallah Mireille , William H M , Hoisington David A
Published: February 2005

A doubled-haploid (DH) population from an intervarietal cross between the Japanese cultivar 'Fukuho-komugi' and the Israeli wheat line 'Oligoculm' was produced by means of wheat × maize crosses. One hundred seven DH lines were genotyped to construct a simple sequence repeat (SSR) based linkage map with RFLP, RAPD, and inter-simple sequence repeat markers. Out of 570 loci genotyped, 330 were chosen based on their positions on the linkage map to create a "framework" map for quantitative trait locus (QTL) analysis. Among the 28 linkage groups identified, 25 were assigned to the 21 chromosomes of wheat. The total map length was 3948 cM, including the three unassigned linkage groups (88 cM), and the mean interval between loci was 12.0 cM. Loci with segregation distortion were clustered on chromosomes 1A, 4B, 4D, 5A, 6A, 6B, and 6D. After vernalization, the DH lines were evaluated for spike number per plant (SN) and spike length (SL) in a greenhouse under 24-h daylength to assess the "gigas" features (extremely large spikes and leaves) of 'Oligoculm'. The DH lines were also autumn-sown in the field in two seasons (1990–1991 and 1997–1998) for SN and SL evaluation. QTL analysis was performed by composite interval mapping (CIM) with the framework map to detect QTLs for SN and SL. A major QTL on 1AS, which was stable in both greenhouse and field conditions, was found to control SN. This QTL was close to the glume pubescence locus (Hg) and explained up to 62.9% of the total phenotypic variation. The 'Oligoculm' allele restricted spike number. The SSR locus Xpsp2999 was the closest locus to this QTL and is considered to be a possible marker for restricted tillering derived from 'Oligoculm'. Eight QTLs were detected for SL. The largest QTL detected on 2DS was common to the greenhouse and field environments. It explained up to 33.3% of the total phenotypic variation. The second largest QTL on 1AS was common to the greenhouse and the 1997–1998 season. The position of this QTL was close to that for the SN detected on 1AS. The association between SN and SL is discussed.Key words: linkage map, microsatellite, QTL, spike length, spike number.
Molecular cytogenetic identification of nullisomy 5B induced homoeologous recombination between wheat chromosome 5D and barley chromosome 5H
Authors: Taketa Shin , Awayama Takaya , Ichii Masahiko , Sunakawa Makoto , Kawahara Tomoko , Murai Koji
Published: February 2005

Chromosome 5H of Hordeum vulgare 'New Golden' (NG) carries a gene(s) that accelerates heading in a wheat background. To introduce the early heading gene(s) of NG barley into the wheat genome, we attempted to induce homoeologous recombination between wheat and NG 5H chromosomes by 5B nullisomy. A nullisomic 5B, trisomic 5A, monosomic 5H plant (2n = 42) was produced from systematic crosses between aneuploid stocks of wheat group 5 chromosomes. A total of 656 F2plants produced by self-fertilization were screened for recombinants by a PCR assay with 3 5H-specific amplicon markers. Twelve plants (1.8%) were selected as putative wheat–barley 5H recombinants. Five of them were inviable or sterile and the remaining 7 were fertile and subjected to the progeny test. Cytological analyses using fluorescence in situ hybridization and C-banding revealed that 6 of the 7 progeny lines are true homoeologous recombinants between the long arms of chromosomes 5D and 5H, but that the other one was not a recombinant having an aberrant barley telosome. The 6 cytologically confirmed recombinant lines included only 2 types (3 lines each), which were reciprocal products derived from exchanges at the same distal interval defined by two flanking markers. One type had a small 5HL segment translocated to the 5DL terminal, and the other type had a small terminal 5DL segment translocated to the 5HL terminal. In the latter type, the physical length of translocated barley segments slightly differed among lines. Homoeologous recombinants obtained in this study should be useful for further chromosome manipulation to introgress a small interstitial 5HL chromosome segment with the early heading gene(s) to wheat. Preferential occurrence of restricted types of recombinants is discussed in relation to homoeologous relationships between wheat and barley chromosomes.Key words: genomic in situ hybridization, homoeologous pairing, Hordeum vulgare, introgression, recombinant, Triticum aestivum.
Inheritance and QTL analysis of durable resistance to stripe and leaf rusts in an Australian cultivar,Triticum aestivum'Cook'
Authors: Navabi A , Tewari J P , Singh R P , McCallum B , Laroche A , Briggs K G
Published: February 2005

An F4-derived F6recombinant inbred line population (n = 148) of a cross between the durable stripe (yellow) rust (caused by Puccinia striiformis) and leaf (brown) rust (caused by Puccinia triticina) resistant cultivar, Triticum aestivum 'Cook', and susceptible genotype Avocet-YrA was phenotyped at several locations in Canada and Mexico under artificial epidemics of leaf or stripe rusts and genotyped using amplified fragment length polymorphism (AFLP) and microsatellite markers. Durable adult plant resistance to stripe and leaf rusts in 'Cook' is inherited quantitatively and was based on the additive interaction of linked and (or) pleiotropic slow-rusting genes Lr34 and Yr18 and the temperature-sensitive stripe rust resistance gene, YrCK, with additional genetic factors. Identified QTLs accounted for 18% to 31% of the phenotypic variation in leaf and stripe rust reactions, respectively. In accordance with the high phenotypic associations between leaf and stripe rust resistance, some of the identified QTLs appeared to be linked and (or) pleiotropic for both rusts across tests. Although a QTL was identified on chromosome 7D with significant effects on both rusts at some testing locations, it was not possible to refine the location of Lr34 or Yr18 because of the scarcity of markers in this region. The temperature-sensitive stripe rust resistance response, conditioned by the YrCK gene, significantly contributed to overall resistance to both rusts, indicating that this gene also had pleiotropic effects.Key words: wheat, rust diseases, Puccinia striiformis, Puccinia triticina, durable resistance, leaf-tip necrosis, QTL analysis.
Genetic diversity of loquat germplasm (Eriobotrya japonica (Thunb) Lindl) assessed by SSR markers
Authors: Soriano José Miguel , Romero Carlos , Vilanova Santiago , Llácer Gerardo , Badenes María Luisa
Published: February 2005

Genetic relationships among 40 loquat (Eriobotrya japonica (Thunb) Lindl) accessions that originated from different countries and that are part of the germplasm collection of the Instituto Valenciano de Investigaciones Agrarias (IVIA) (Valencia, Spain) were evaluated using microsatellites. Thirty primer pairs flanking microsatellites previously identified in Malus × domestica (Borkh.) were assayed. Thirteen of them amplified polymorphic products and unambiguously distinguished 34 genotypes from the 40 accessions analyzed. Six accessions showing identical marker patterns were Spanish local varieties thought to have been derived from 'Algerie' by a mutational process very common in loquat species. A total of 39 alleles were detected in the population studied, with a mean value of 2.4 alleles per locus. The expected and observed heterozygosities were 0.46 and 51% on average, respectively, leading to a negative value of the Wright's fixation index (–0.20). The values of these parameters indicate a smaller degree of genetic diversity in the set of loquat accessions analyzed than in other members of the Rosaceae family. Unweighted pair-group method (UPGMA) cluster analysis, based on Nei's genetic distance, generally grouped genotypes according to their geographic origins and pedigrees. The high number of alleles and the high expected heterozygosity detected with SSR markers developed in Malus × domestica (Borkh.) make them a suitable tool for loquat cultivar identification, confirming microsatellite marker transportability among genera in the Rosaceae family.Key words: Eriobotrya japonica, SSR markers, microsatellites, genetic diversity.
Zig-Zag Defects and Disclinations in the Surface-Stabilized Ferroelectric Liquid Crystals
Authors: Ouchi Yukio , Takano Hideo , Takezoe Hideo , Fukuda Atsuo
Published: February 2005

Characteristic features of zig-zag defects and disclinations in surface-stabilized ferroelectric liquid crystal cells are presented. It is pointed out that there exist two kinds of zig-zag defects, i.e., a lightning type and a hairpin type, which appear alternatively along the smectic layer normal. This fact indicates that two types of mismatching of a layer bend structure cause two kinds of zig-zag defects. Switching between two twisted states occurs with the formation of internal boat-shaped disclination loops in relation to the zig-zag defects. The nucleation process of the boat-shaped domains is quite characteristic; the bows appear on each side of the bright hairpin-type lines, while the sterns appear on both sides of the dark lightning-type lines. A model structure is proposed in order to interpret the experimental observation around the zig-zag defect lines on the basis of disclination dynamics.
Calculations for the Distribution Function of Energetic Electrons in a Helium Hollow Cathode Glow Discharge with the Monte Carlo Method
Authors: Hashiguchi Seishiro , Hasikuni Mitugi
Published: February 2005

The distribution function of energetic electrons is calculated by tracing their trajectories with the Monte Carlo method. Electrons were made to have inelastic and elastic collisions with helium atoms in the ground state. Calculations were made for a cylindrical hollow cathode whose inner diameter is 1 cm. The electron density increased rapidly with decreasing energy near the lower limit of its energy. The number density of electrons whose energy equals the cathode-fall potential has a peak at the central axis. Their velocities are found to be directed along a collisionless trajectory. The broad angular distribution of the velocity was found in slower electrons. The peak of the number density at the central axis decreased with increasing pressure. The energetic electrons can hardly penetrate into the central region when the gas pressure is 1.3 kPa.
Hole Injection from Polypyrrole Electrode into Organic Photoconductors
Authors: Kubo Izumi , Hanna Jun-ichi , Yamamoto Shigeru , Kokado Hiroshi
Published: February 2005

The interfacial hole infection from a conductive polymer to organic photoconductors was investigated. Polypyrrole in film was electrochemically synthesized on an indium-tin-oxide coated glass substrate and used as the conductive polymer. For the organic polymer to be coupled with the polypyrrole electrode, poly (N-vinylcarbazole) (PVK) or polycarbonate molecularly doped with one of the hole-transporting materials having a redox potential in the range of 0.09 to 0.6 V, was chosen. The hole injection was found to be a function of the conductivity. From the experiments using molecularly doped polycarbonate, it was pointed out that hole-transporting materials of lower oxidation potentials inject more holes. An acceleration of the injection was observed to take place from a photo-excited polypyrrole layer into a PVK or a hole-transporting layer doped with molecules of an adequate oxidation potential (0.21 V).
Measurement and Analysis of the Static Debye-Waller Factor of Cz-Silicon with Small Oxygen Precipitates
Authors: Iida Satoshi , Sugiyama Hiroshi , Sugita Yoshimitsu , Kawata Hiroshi
Published: February 2005

The static Debye-Waller factor and its dependence on the crystal perfection have been obtained through the detailed analysis of the intensity distribution in X-ray diffraction topograph for heat-treated Cz-silicon crystals. The size and density of oxygen precipitates have been determined using the experimental and calculated static Debye-Waller factors and the results of the infrared absorption experiments.
Selective Deposition of Silicon Oxide Using a Plasma-Fluorinated Resist Mask
Authors: Awaya Nobuyoshi , Arita Yoshinobu
Published: February 2005

The characteristics of plasma-fluorinated resist as a deposition preventive mask for the selective deposition of silicon oxide is investigated. It is shown that the surface energy of conventional photoresist is markedly decreased by NF3 plasma. This fluorinated resist mask accomplishes the selective deposition of silicon oxide by the hydrolysis reaction of SiCl4.
Flattening the Surface of CaF2/Si(100) Structures by Post-Growth Annealing
Authors: Asano Tanemasa , Ishiwara Hiroshi , Furukawa Seijiro
Published: February 2005

The surface morphologies of CaF2 films epitaxially grown on Si(100) substrates by vacuum evaporation are investigated by replica transmission electron microscopy and reflection electron diffraction analyses. It is found that {111} facets, which appear at the surface of as-grown CaF2 films, are extirpated and the surface is flattened by post-growth annealing at temperatures above 650degC. Both ex situ annealing and in situ annealing are used, and the in situ annealing is shown to be useful for flattening the surface without generating cracks. The post-growth annealing is also effective in improving the crystalline quality of the CaF2 films, as measured by ion channeling measurements. Usefulness of a two-step growth method for growing smooth CaF2 films is demonstrated. From observations of the dynamical process of the surface flattening, it is pointed out that mass transports for the flattening are dominantly progressed by surface diffusion.
Magnetostriction and Perpendicular Magnetic Anisotropy of Amorphous GdFeCo Thin Films
Authors: Yoshino Seiji , Tsunashima Shigeru , Masuda Morio , Uchiyama Susumu
Published: February 2005

The saturation magnetostriction constant λs, and the perpendicular magnetic anisotropy K
u of amorphous Gd
x
(Fe100-y
Co
y
)100-x
(9.5<x<50) films prepared by dc-biased rf sputtering have been measured at room temperature. In films with high Co concentration, λs showed strong dependence on Gd content, whereas in Fe-rich films, λs showed weak dependence. Furthermore, it was confirmed that λs was not affected by the substrate bias voltage V
b, although K
u strongly depended on V
b.
Experimental Study on a Propagating Flame by a Laser Light Scattering Method
Authors: Yamamoto Kazuhiko , Terao Kunio
Published: February 2005

The ionized state in a flame propagating in a stoichiometric propane-oxygen mixture was investigated by a laser light scattering method. The charged particles, H-ions, C-ions or O-ions and free electrons, having an anomalously high temperature from 104 to 105 K were observed on both sides of the flame front, i.e. in the front of the flame as well as behind it, where the adiabatic combustion temperature should be about 3000 K. The results suggest that the measured values of the electron and ion temperatures as well as those of the electron density fluctuate over a wide range.
Carrier Transport Mechanisms of InSe p-n Homojunction
Authors: Shigetomi Shigeru , Ikari Tetsuo , Koga Yutaka , Shigetomi Shigenobu
Published: February 2005

InSe p-n homojunctions have been fabricated by bringing the cleavage surfaces (c-plane) of undoped n-type and Zn-doped p-InSe into direct contact. The mechanisms of carrier transport across the junction in the dark and under illumination are investigated by current-voltage, capacitance-voltage characteristics and spectral response of the short-circuit current. The experimental results indicate that this homojunction fabrication method is effective for electrical and optoelectronic devices.
Preparation of High Quality Polypyrrole Films
Authors: Nakazawa Yusuke , Ebine Toshihiro , Kusunoki Mitsugu , Nishizawa Hideyuki , Hanna Jun-ichi , Kokado Hiroshi
Published: February 2005

Influences of the polymerization condition on properties of electrochemically synthesized polypyrrole film were studied with the aim of preparing high quality films for device application. Polymerization condition parameters such as the content of dissolved oxygen in the electrolytic solution, the polymerization temperature, the concentrations of monomer and supporting electrolyte, and others were varied, and the conductivity, the surface morphology, and adhesion to substrate of resulting films were examined. High quality films were synthesized as double-layered films consisting of a thin well adherent sublayer and a highly conductive thick overlayer. Optimizing various parameters, we could obtain high quality films with a satisfactorily flat surface, good adhesion to substrate, and a high conductivity (more than 300 S/cm).
Resistivity Correction Factor for Four-Probe Method on Circular Semiconductors II
Authors: Yamashita Masato
Published: February 2005

A method which improves ease and accuracy of calculation of the resistivity correction factor (RCF) is described. The method applied for the system consists of a circular semiconductor and a four-probe array. The method of images is introduced to obtain the RCF. The equivalent current source and sink for circular current probes are derived by taking into account the image current probes as well as the actual current probes.
Numerical evaluations show that for thicker samples the calculation of the RCF is speeded up, and decrease in the RCF due to the image current probes becomes remarkable in the vicinity of the sample edge.
Raman Scattering Measurements of Strains in ZnSe Epitaxial Films on GaAs
Authors: Nakashima Shin-ichi , Fujii Akihito , Mizoguchi Kohji , Mitsuishi Akiyoshi , Yoneda Kiyoshi
Published: February 2005

Raman spectroscopy has been applied to the evaluation of strains in ZnSe films grown by molecular beam epitaxy on GaAs. The observed variation of the ZnSe LO phonon frequency with thickness is explained well in terms of the conversion from the elastic strain due to accommodation of the lattice mismatch to the thermal strain due to the difference in thermal expansion coefficients of the substrate and epitaxial film. The strains estimated from the Raman measurements are consistent with the results obtained from X-ray analyses by other researchers.
Sublattice Contributions on Faraday Rotation in Annealed {YBi}3[Fe2-xGax](Fe3-yGay)O12
Authors: Numata Takuhisa , Muraoka Shunsaku , Inokuchi Seiji , Sakurai Yoshifumi
Published: February 2005

Sublattice contributions on the Faraday rotation were studied in BiGa:YIG films in which the sublattice moments were modified through an intersite migration of nonmagnetic Ga3+ by annealing. Linear combination of a- and d-site moments on the rotation was observed with a deviation of less than 0.5%. a-site Fe3+ had larger influence on the rotation although it seemed to depend on the Bi concentration.
A Method for Molecular Alignment of Ferroelectric Smectic Liquid Crystal: Combination of Metal Oxide Thin Film and Electric Field
Authors: Kuwahara Michio , Kawata Yasushi , Onnagawa Hiroyoshi , Miyashita Kazuo
Published: February 2005

A method for molecular alignment of a ferroelectric smectic liquid crystal is reported. Homeotropic alignment with a small angle of pretilt was obtained by surface treatment with oblique deposition of metal oxide, such as yttria and alumina. Furthermore, an electric field was applied during the cooling period from isotropic liquid to chiral smectic phase. Uniformly pretilted alignment could be obtained by using the oblique deposition and DC field application. On the other hand, a twisted alignment was obtained on the obliquely deposited metal oxide film when an AC electric field was applied instead of a DC field. Electrooptical characteristics of these cells are shown.
High-Rate Deposition of a-Si:H Film with a Separated Plasma Triode Method
Authors: Tanaka Makoto , Ninomiya Kunimoto , Nakamura Noboru , Tsuda Shinya , Nakano Shoichi , Ohnishi Michitoshi , Fuwano Yukinori
Published: February 2005

The separated plasma triode (SPT) method has been developed to deposit high-quality a-Si:H films at high deposition rates. Plasma properties were measured by a probe method and an optical emission spectroscopy (OES) method. It is possible to improve the electron density in a plasma without increasing the plasma potential near the substrate by the SPT method. High-quality a-Si:H films and high-performance a-Si solar cells were obtained at high deposition rates using the SPT method.
Low-Energy Double-Ion-Beam Deposition System
Authors: Yoshida Yoshikazu , Ohnishi Teruhito , Sekihara Toshinobu , Hirofuji Yuichi
Published: February 2005

A low-energy double-ion-beam deposition system for high-quality thin-dielectric-film formation has been developed. The system consists of two beam lines (a mental ion beam line and a gas ion beam line) and has a new type of ion-beam deceleration electrodes which can be moved like a folding screen. In this system, decelerated Ta+ and oxygen ion beams of about 80 and 180 µA/cm2, respectively, were obtained in a final-energy range of 100∼200 eV. In a deposition test, by simultaneously irradiating with a mass-separated Ta+ ion beam and an oxygen ion beam, pure and soichiometric Ta2O5 films of 50 nm thickness were obtained in one hour at room temperature.
Oxidation Properties of Silicon Nitride Thin Films Fabricated by Double Tubed Coaxial Line Type Microwave Plasma Chemical Vapor Deposition
Authors: Kato Isamu , Numada Kouji , Kiyota Yukihiro
Published: February 2005

Silicon nitride films have been fabricated under different deposition conditions using a double tubed coaxial line type microwave plasma chemical vapor deposition system. The oxidation and annealing properties of the films have been analyzed using infrared absorption spectroscopy. It is shown that oxidation proceeds via (Si-H2)
n
bonds in the voids. During the process, hydrogen atoms are released. The N-H bonds which form the remainder in the bulk are not affected by oxidation. Based on this finding, films which have a large concentration of N-H bonds and a lower concentration of Si-H bonds show greater resistance to oxidation. Under adequate conditions, the stoichiometric oxidation-resistant silicon nitride films can be fabricated outside the discharge plasma even at room temperature.
Electron Emission Enhancement of a (W-Sc2O3)-Coated Impregnated Cathode by Oxidation of the Coated Thin Film
Authors: Yamamoto Shigehiko , Taguchi Sadanori , Watanabe Isato , Sasaki Susumu
Published: February 2005

A monoatomic order surface layer composed of Ba, Sc and O reduces the work function and, thus, enhances electron emission of a (W-Sc2O3)-coated impregnated cathode surface. The dependency of the electron emission property of the new impregnated cathode on the coated film property is evaluated by intentionally oxidizing the coated film during the film deposition process. The degree of oxidation is monitored by measuring the resistivity ratio (room temperature/liquid nitrogen temperature) of the coated film. It is found that the electron emission is enhanced when the resistivity ratio is in the range of 0.8 to 0.9. This leads to a novel electron emission enhancement model: Electron emission enhancement is caused by free Sc atoms produced by the reaction of Ba atoms with Sc2W3O12 which is formed as the result of the oxidation process and heat treatment followed.
An Antenna-Coupled Warm Carrier Device Using Polycrystalline Ge Films
Authors: Inoue Narumi , Yasuoka Yoshizumi
Published: February 2005

Evaporated Ge films were used as antenna-coupled point-contact warm carrier devices. The carrier mobilities of the deposited films increased with the increase of the substrate temperature and showed 10-100 cm2/V·s for the films deposited above 300°C. A CO2 laser signal was detected by the point-contact devices fabricated from those films. This indicated the potential of the realization of antenna-coupled thin-film warm carrier devices.
Reflection High-Energy Electron Diffraction Studies of Indium Phosphide Surface
Authors: Naseem Shahazad
Published: February 2005

Reflection high-energy electron diffraction studies of single-crystal indium phosphide substrates have been performed. It is shown that the substrates do not undergo any deleterious changes during chemical etching or the back contact sintering process. The low-power plasma exposure of the substrates is, however, responsible for structural modifications at the front surface and the performance of indium tin oxide/indium phosphide solar cells.
AlGaSb Single, Double and Multiple Heterostructures Grown by Liquid-Phase Epitaxy and their Photoluminescence Properties
Authors: Ichimura Masaya , Takeda Yoshikazu , Sasaki Akio
Published: February 2005

AlGaSb multiple heterostructures were grown at 300°C by liquid phase epitaxy (LPE). Multiple heterostructures composed of 10 layers were characterized by Auger electron spectroscopy and X-ray diffraction. The compositional modulation of a period of 600 Å was clearly observed. From the well layers of the multiple and the double heterostructures, a strong single peak of photoluminescence was observed. This confirms that LPE grown heterointerfaces are of fairly good quality. The photoluminescence properties of different heterostructures are discussed in terms of carrier diffusion, carrier confinement, and quantization levels.
Low Energy Electron Diffraction and X-Ray Photoelectron Spectroscopy Studies of the Formation of Submonolayer Interfaces of Sb/Si(111)
Authors: Park Chong-Yun , Abukawa Tadashi , Kinoshita Toyohiko , Enta Yoshiharu , Kono Shozo
Published: February 2005

Surface reconstructions of a submonolayer Sb/Si(111) system were investigated by low-energy electron diffraction and X-ray photoelectron spectroscopy. It has been found that the surface superstructures of diffuse 2×2 (or three-domain 2×1), √3×√3, 5√3×5√3 and 7√3×7√3 are formed for the Sb coverages around one monolayer.
Influence of Ion Sputtering on Auger Electron Spectroscopy Depth-Profiling of GaAs/AlGaAs Superstructure
Authors: Matsunaga Fumiko , Kakibayashi Hiroshi , Mishima Tomonori , Kawase Susumu
Published: February 2005

The resolution of depth profiling by Auger electron spectrscopy (AES) changes depending on ion sputtering conditions due to implanted ion effects such as knock-on and cascade mixing. To evaluate the influence of these effects on depth profiling, profile broadening due to ion sputtering was measured using different levels of energy and species of ions. In addition, the altered layer's thickness was estimated.
Light-Ion Beam Focusing by z-Discharged Plasma Channel
Authors: Murayama Minoru , Nemoto Masahiro , Masugata Katsumi , Yatsui Kiyoshi
Published: February 2005

Experimental and theoretical studies of proton-beam focusing by a z-discharged plasma channel that produces an azimuthal magnetic field are presented. The channel is produced in a Pyrex tube (50 mm in diameter, 140 mm in length) at a pressure of 0.2 Torr (air), which is fired by a fast capacitor bank (1.9 µF, 60 kV). A proton beam extracted from a flat-type, magnetically-insulated diode (850∼990 kV, 80 kA, 75 ns) is injected into the channel which is typically fired at voltage ∼32 kV and current ∼52 kA. Experimentally, we have observed the density enhancement at the focal point with a factor of (11∼15). Numerical calculation has also been carried out on trajectories of proton beams, assuming them only to be subject to Lorentz force. A reasonable agreement between the experiment and the theory is obtained on the focusing point or the enhancement factor of the density.
Deep Levels in Non-Doped and Donor-Doped GaP
Authors: Endo Tamio , Uchida Eiji , Hirosaki Yuushi , Sugiyama Koichi
Published: February 2005

Four deep electron-trap levels were detected by DLTS from the non-doped and Te- or S-doped LEC-grown GaP. Some discussions are given regarding their origin. The density N
t of these levels increased linearly with the net donor density N
D for non-doped samples. N
t was reduced by doping Te with N
D∼1017 cm-3, and then increased as N
D
1.7 for N
D>1017 cm-3.
Effect of Hall Current on Hydromagnetic Free Convection Flow near an Accelerated Porous Plate
Authors: Hossain M. A. , Mohammad K.
Published: February 2005

The effect of free convection current on the unsteady flow of MHD viscous and incompressible fluid past a uniformly accelerated vertical porous plate imbedded in a uniform applied magnetic field transverse to it is investigated, on the assumption that the induced magnetic field is negligible compared with the imposed magnetic field. The series solution for the velocity and the skin friction are obtained under the assumption that the hydromagnetic parameter M
t is small. The velocity profiles are shown graphically with the effect of the Hall parameter m, the magnetic field parameter M
t, the Grashof number G
r and the transpiration parameter a for a single value of the Prandtl number P
r=0.71 which represents air at 20°C. The numerical values of the skin friction components are given in tabular form for different values of these parameters.
Improvement of a Flat Surface Circular Buried Heterostructure GaInAsP/InP Surface Emitting Laser
Authors: Kawasaki Hideshi , Koyama Fumio , Iga Kenichi
Published: February 2005

The surface quality of a flat surface circular buried heterostructure (FCBH) is improved by reducing the diameter of circular mesa to ∼ 15 µmφ. The minimum threshold current is I
th=12 mA at 77 K under CW condition, which is the lowest value ever obtained for GaInAsP/InP surface emitting lasers.
Gas Source MBE Growth of GaSb
Authors: Ito Hiroshi , Ishibashi Tadao
Published: February 2005

Gas source molecular beam epitaxal growth of GaSb is investigated. Sb(CH3)3 is found to decompose effectively when the cracking furnace temperature is higher than 800°C. A mirror-like GaSb epi-layer is shown to be obtainable using Sb(CH3)3 and a solid Ga source for the first time.
Hole Assisted Gunn Oscillation in Dumbbell Shaped Germanium
Authors: Kim Chul Koo , Moon Hwan Goo , Choi Jong Ki , Kwon Tae Song , Nahm Kyun
Published: February 2005

Hole assisted Gunn oscillation mechanism is proposed to explain the current oscillation in dumbbell shaped single crystal Ge. It is shown that the presence of equal amount of electrons and holes and the dumbbell shape jointly create the space charge and field fluctuation which, in turn, produces the Gunn oscillation. Experimental observations are discussed in the light of the proposed model.
Analysis of GaSb/AlSb Strained Layers Superlattices Using Small Angle X-Ray Diffraction
Authors: Villaflor Antonio Basanes , Inoue Yuji , Kimata Morihiko
Published: February 2005

Strained layer superlattices of GaAs and AlSb are analysed by augmenting (004) double crystal X-ray diffraction with small angle diffraction. The measurement of layer widths by the latter method will be shown to be more accurate since it does not involve any assumption on the state of strain. The results are confirmed by photoluminescence at 77 K. Actual strain is calculated from the average lattice parameter and the AlSb mole fraction obtained by (004) and small angle diffraction, respectively. The shift in the heavy hole band gaps of the layers due to the in-plane bi-axial stress is then discussed.
Transparent and Conductive Cadmium-Tin Oxide Films Deposited by Atom Beam Sputtering
Authors: Nakazawa Tatsuo , Ito Kentaro
Published: February 2005

Transparent and conductive cadmium-tin oxide films with resistivities of 9×10-4 Ω cm and transmittance higher than 80% over the visible range were prepared by atom beam sputtering. The structure of the deposited film was amorphous and its composition was highly deficient in CdO compared with Cd2SnO4. This CTO film was used as the window layer of a heterojunction solar cell.
Proton NMR in Degraded Powder of YBa2Cu3O7-δ
Authors: Nishihara Hironori , Nishida Nobuhiko , Takabatake Toshiro , Kishio Kohji , Ohtomo Akira , Hayashi Koya , Ishikawa Masayasu , Nakazawa Yasuhiro , Koga Kei-ichi , Tamegai Tsuyoshi , Kitazawa Koichi
Published: February 2005

Pulsed NMR of 1H has been applied to characterize aged powders of YBa2Cu3O7-δ and its family. A proton site with an internal field of 150 Oe, which is from antiferromagnetically ordered copper moments, has been observed in antiferromagnetic, tetragonal Yba2Cu3O7-δ. A proton signal inside the superconducting region of orthorhombic YBa2Cu3O7-δ has been observed together with signals from regions of nonmagnetic, nonsuperconducting degraded products for both cases. Overall features are interpreted along with a recently proposed topotactic mechanism of hydration reaction.
Spectral Distribution of Photocurrent near the Absorption Edge
Authors: Tanabe Yoshikazu , Yamanaka Tadae
Published: February 2005

Two analytically solvable mathematical models were discussed to explain a peak near the absorption edge in the photocurrent spectrum. The monomolecular process model involving the diffusion and the drift with surface recombination clarified the conditions that the diffusion effect is dominant with the surface recombination or the drift effect. The bimolecular recombination model without diffusion under very low applied field also shows a peak near the absorption edge. These models have different dependences of the photoconductivity on the incident light intensity and on the applied electric field.
Irradiation Effects of 60Co γ-Ray on the near Band-Edge Photoluminescence (PL) of ZnSe
Authors: Mochizuki Katsumi , Masumoto Katashi
Published: February 2005

Near band-edge photoluminescence (PL) in ZnSe single crystals irradiated with 60Co γ-ray of various dosages was examined at 4.2 K. The emission intensity of the so-called I
1
D(445.3 nm) and Y
0(476.0 nm) lines increases obviously with increasing dosage and decreases after anneling. It is concluded that these emission lines are closely related to the native lattice defects, which are probably a zinc vacancy (V
Zn) for the I
1
D line and a dislocation for the Y
0 line.
Magneto-Optical Kerr Rotation and Sublattice Magnetic Moments in RE-Co Sputtered Films
Authors: Honda Shigeo , Yoshiyama Masatoshi
Published: February 2005

Temperature and compositional dependences of magnetization rare earth (RE=Gd, Tb, Dy, Nd)-Co sputtered films are analysed using the mean field theory, and the sublattice magnetic momentsMCoandMREare calculated as a function of composition. The Kerr rotation angle θKis measured at room temperature in a range of optical wavelenghs from 400 nm to 670 nm. The compositional variation of θKcan be described by a model in which two sublattice magnetic moments contribute to θKindependent of each other in an additive or a subtractive fashion:K(Co)MCo±K(RE)MRE. The value ofK(Co) coincides approximately with that of a pure Co film, whereasK(RE) depends on the RE element significantly.
Continuous Propagation of a Vertical Bloch Line Pair around the Stripe Domain Stabilized by a Co-Cr Film
Authors: Saitoh Fumihiko , Ono Takeo , Oda Hitoshi
Published: February 2005

A stripe domain (SD) was stabilized by a patterned Co-Cr film. The bias field range for the stabilization was 2 or 3 Oe. The SD was stretched and shrunk for read-write operation. Vertical Bloch lines (VBLs) were observed by rocking under the Co-Cr pattern 10 µm in width. A VBL pair was propagated continuously around the SD by applying pulsed bias fields perpendicular to the film. The motion of the VBL pair was observed by rocking. The velocity of the propagation was about 2.0×104 cm/s at pulse amplitude 40 Oe and pulse width 8 ns. This was comparable to that of the SD stabilized by a loop conductor: 2.5×104 cm/s
Polarization Control by Optical Feedback in Semiconductor Lasers
Authors: Toda Tsuyoshi , Ogasawara Nagaatsu , Ito Ryoichi
Published: February 2005

Control of the polarization state of semiconductor lasers is achieved by placing a polarizer in an external cavity. The TE and TM components of the laser beam are coupled with each other by the polarizer under optical feedback. The experimental results are explained by a coupled-mode model.
Thermal Donor Formation and the Effect of Copper Contamination in Oxygen-Doped Germanium
Authors: Fukuoka Noboru , Tabuchi Mitsuru , Matsuda Koji
Published: February 2005

The structure of thermal donors in germanium was studied in oxygen-doped crystal (9×1016oxygens/cm3). From the reduction of interstitial oxygen concentration after annealing, it was found that a single thermal donor contains three oxygen atoms on average. The diffusion of copper atoms from the surface in oxygen-doped germanium crystal was studied through electron irradiation effects. It was revealed that a copper atom migrates as an interstitial atom and it occupies a substitutional site at about 450°C.