bluuebunny/crossref_metadata_2025 huggingface dataset:
The importance of bacterial growth phase for in planta virulence and pathogenicity testing: coordinated stress response regulation in fluorescent pseudomonads?
Authors: Klotz Martin Gunter
Published: May 2010

Phytopathogenic strains of Pseudomonas syringae have different physiological properties in their different growth phases. Screening of four strains at the cellular level revealed that the sensitivity of P. syringae to oxidative stress, heat, and selected antibiotics is correlated with the growth phase and enzyme properties and is affected by the composition of the nutrient environment. The interrelation of responses to different stresses allows the conclusion to be made that coordinated stress response regulation occurs in some strains of P. syringae. This is important for studies that involve plant–bacteria associations in which the microbes have to cope with complex stress situations. It further opens an avenue of screening at the molecular level for stress response regulons in fluorescent pseudomonads.Key words: Pseudomonas syringae, antibiotics, catalase, growth phase, stress.
Parasitism of oospores of Pythium spp. by strains of Actinoplanes spp.
Authors: Khan N. I. , Filonow A. B. , Singleton L. L. , Payton M. E.
Published: May 2010

Strains of Actinoplanes spp. were evaluated for their in vitro parasitism of oospores of Pythium aphanidermatum, Pythium arrhenomanes, Pythium irregulare, Pythium myriotylum, and Pythium ultimum. Oospores of Pythium arrhenomanes, Pythium irregulare, and Pythium myriotylum were identified for the first time as hosts of Actinoplanes spp. Newly recorded parasites of oospores of Pythium spp. were Actinoplanes azureus, Actinoplanes brasiliensis, Actinoplanes caeruleus, Actinoplanes ferrugineus, Actinoplanes ianthinogenes, Actinoplanes italicus, Actinoplanes minutisporangius, Actinoplanes rectilineatus, Actinoplanes teichomyceticus, Actinoplanes utahensis, Actinoplanes violaceous, Actinoplanes yunnahenis, plus 15 strains of Actinoplanes yet to be speciated. Parasitized oospores had disorganized cytoplasms and hyphae of Actinoplanes sp. emerging from them. Infection of oospores in vitro varied from 0 to > 90%. Strains also were very active parasites of oospores in sterile soils. When added to nonsterile soils, several strains increased (p = 0.05) the level of oospore parasitism compared with nonsupplemented soils. Strains of Actinoplanes spp. exhibited a host specificity for species of Pythium in vitro and in soil. Sporulation of Actinoplanes sp. from infected oospores incubated on soil was frequent and more abundant than that observed in vitro.Key words: Pythium spp., Actinoplanes spp., actinomycetes, biological control, host–parasite specificity.
Maintenance of infective Borrelia burgdorferi Sh-2-82 in 4% oxygen – 5% carbon dioxide in vitro
Authors: Austin Faye E.
Published: May 2010

The infectivity of Borrelia burgdorferi depends on the number of passages in Barbour–Stoenner–Kelly (BSK-II) medium in ambient air. In this study the parameters of medium formulation or O2–CO2 atmosphere were altered to define conditions that would retain borrelial infectivity upon serial passage. The infective strain Sh-2-82 was passaged 20 times in BSK-II and BSK-A (a modified BSK-II medium) in ambient O2–CO2 and BSK-II in 4% O2 – 5% CO2 – 91% N2. Spirochetes of every fifth passage were inoculated intraperitoneally into neonatal Lewis rats. Infectivity was lost after 15 passages in media in ambient O2–CO2. However, infectivity was maintained through all 20 passages in BSK-II in 4% O2 – 5% CO2 – 91% N2. There were no pH differences, but the dissolved O2 concentration in ambient O2–CO2 was approximately twice that in 4% O2 – 5% CO2 – 91% N2. Therefore, differences in infectivity were due to culturing under a constant environment of decreased O2 and increased CO2. This environment may place a selective pressure on the borreliae for retention of the infective phenotype. The results suggest that the levels of O2 and CO2 in the environment influence infectivity by preventing the loss of genetic information or inducing the expression of virulence determinants in B. burgdorferi.Key words: Borrelia burgdorferi; Lyme disease, infectivity, serial passage.
Exogenous rh-urokinase modifies inflammation and Pseudomonas aeruginosa infection in a rat chronic pulmonary infection model
Authors: Hart David A. , Green Francis , Whidden Paul , Henkin Jack , Woods Donald E.
Published: May 2010

The effect of recombinant human urokinase (rh-UK) in a rat model of chronic Pseudomonas aeruginosa pulmonary infection was studied. Efficacy was assessed by lung histology and quantitative bacteriology. Male Sprague–Dawley rats received 1 × 104 or 1 × 105P. aeruginosa encapsulated in agar beads via the intratracheal route on day 1. Intratracheal administration of up to 12 500 units of rh-UK on day 21 led to a dose-dependent disappearance of viable organisms from the lungs by day 24 in rats receiving 104 organisms. In slightly longer term infections (30 days), rh-UK was still effective in facilitating the disappearance of the organisms from the lungs of most of the treated animals. rh-UK was effective in eliminating organisms when animals were infected with 104, but not 105 bacteria. In vitro analysis revealed that rh-UK was not directly toxic for the organisms. Histologically, lungs from short-term infected control animals exhibited acute inflammation, inflammatory cell infiltrates, and fibrin deposition. Histology of lungs from UK-treated, short-term infected rats revealed decreased airway inflammation and cellular infiltration compared with infected controls. Lungs from infected animals treated with 12 500 units of rh-UK were histologically indistinguishable from the lungs of uninfected control animals, except for the foreign body reaction. These results indicate that exogenous rh-UK may be efficacious in the treatment of pulmonary inflammation accompanying exposure to Gram-negative bacteria such as P. aeruginosa.Key words: chronic pulmonary infection, Pseudomonas aeruginosa infection, fibrinolysis, urokinase.
Succinic and lactic acids as plant growth promoting compounds produced by rhizospheric Pseudomonas putida
Authors: Yoshikawa Masami , Hirai Nobuhiro , Wakabayashi Kohji , Sugizaki Haruyuki , Iwamura Hajime
Published: May 2010

In greenhouse trials, root growth of Asparagus officinalis L. increased up to 30% when roots of 3-week-old seedlings were dipped in the culture filtrate of Pseudomonas putida RSA9, a strain isolated from rhizosphere soil of asparagus and antagonistic to the crown rot pathogen Fusarium moniliforme. The culture filtrate was extracted with ethyl acetate at pH 3, and the extracts were fractionated on a column of octadesylsilica gel. The active fraction was found to be a 45:55 mixture of succinic and lactic acids. Root mass increased 40% when the roots of the seedlings were treated with a 1:1 mixture of the acids at 10 ppm. The results provide an explanation for the plant growth promoting effects of some rhizobacteria; the bacteria may secrete organic acids, such as succinic and lactic acids, and these acids may increase plant growth under conditions in which the populations of pathogens are reduced.Key words: succinic acid, lactic acid, Pseudomonas putida, plant growth promotion, rhizobacteria, PGPR.
Detection and characterization of a bacteriocin produced by Lactobacillus plantarum C19
Authors: Atrih A. , Rekhif N. , Milliere J. B. , Lefebvre G.
Published: May 2010

Strain C19, isolated from fermented cucumbers and identified as Lactobacillus plantarum, produced a bacteriocin. This bacteriocin, named plantaricin C19, was stable at acidic pH, was relatively thermostable, and had a molecular mass of about 3.5 kDa. It inhibited some pathogenic (i.e., Listeria spp.) and spoilage Gram-positive bacteria but had weak or no action against lactic acid bacteria. Its adsorption on sensitive and resistant bacteria was pH dependent and was reduced by pretreatment of cells with lipase or lysozyme. Curing treatments with acriflavine or novobiocin yielded nonproducing mutants sensitive to plantaricin C19.Key words: lactic acid bacteria, Lactobacillus plantarum, bacteriocin, protein.
The structure of the antigenicO-polysaccharide in the lipopolysaccharide of enterohaemorrhagicEscherichia coliserotype O71:H12
Authors: MacLean Leann L. , Vinogradov Evgeny , Perry Malcolm B.
Published: May 2010

The antigenic O-polysaccharide component of the lipopolysaccharide produced by Escherichia coli serotype O71:H12 was analyzed by chemical composition, nuclear magnetic spectroscopy, and Smith-type periodate oxidation methods. It was determined to be a partially O-acetylated unbranched polymer of a repeating tetrasaccharide unit composed of l-rhamnose, d-galactose, 2-acetamido-2-deoxy-d-galactose, and 3-acetamido-3-deoxy-d-quinovose (1:1:1:1) residues having the following structure: [Formula: see text]
Origami in outer membrane mimetics: correlating the first detailed images of refolded VDAC with over 20 years of biochemical data
Authors: Summers William A.T. , Court Deborah A.
Published: May 2010

Mitochondrial porin forms an aqueous pore in the outer membrane, through which selective passage of small metabolites and ions occurs, thereby regulating both mitochondrial function and cellular respiration. Investigations of the structure and function of porin have been performed with whole mitochondria, membrane vesicles, artificial membranes, and in detergent solutions, resulting in numerous models of porin structure. The mechanisms by which this protein functions are undoubtedly linked to its structure, which remained elusive until 2008, with reports of 3 high-resolution structures of this voltage-dependent, anion-selective channel (VDAC). The barrel structure is relatively simple yet unique: it is arranged as 19 anti-parallel β-strands, with β-strands 1 and 19 aligned parallel to each other to close the barrel. The N-terminal helical component is located within the lumen of the channel, although its precise structure and location in the lumen varies. With the basic barrel structure in hand, the data obtained in attempts to model the structure and understand porin over the past 20 years can be re-evaluated. Herein, using the mammalian VDAC structures as templates, the amassed electrophysiological and biochemical information has been reassessed with respect to the functional mechanisms of VDAC activity, with a focus on voltage-dependent gating.
Structural analysis of DNA interaction with retinol and retinoic acid
Authors: Mandeville J. S. , N’soukpoé-Kossi C. N. , Neault J. F. , Tajmir-Riahi H. A.
Published: May 2010

Dietary constituents of fresh fruits and vegetables may play a relevant role in DNA adduct formation by inhibiting enzymatic activities. Studies have shown the important role of antioxidant vitamins A, C, and E in the protection against cancer and cardiovascular diseases. The antioxidant activity of vitamin A and beta-carotene may consist of scavenging oxygen radicals and preventing DNA damage. This study was designed to examine the interaction of calf-thymus DNA with retinol and retinoic acid in aqueous solution at physiological conditions using a constant DNA concentration and various retinoid contents. Fourier transform infrared (FTIR), circular dichroism (CD), and fluorescence spectroscopic methods were used to determine retinoid binding mode, the binding constant, and the effects of retinol and retinoic acid complexation on DNA conformation and aggregation. Structural analysis showed that retinol and retinoic acid bind DNA via G-C and A-T base pairs and the backbone phosphate groups with overall binding constants of Kret = 3.0 (±0.50) × 103 (mol·L–1)–1 and Kretac = 1.0 (±0.20) × 104 (mol·L–1)–1. The number of bound retinoids per DNA were 0.84 for retinol and 1.3 for retinoic acid. Hydrophobic interactions were also observed at high retinol and retinoic acid contents. At a high retinoid concentration, major DNA aggregation occurred, while DNA remained in the B-family structure.
Stimulation of regulatory volume increase (RVI) in avian articular chondrocytes by gadolinium chloride
Authors: Ong Sang-Bing , Shah Dinesh , Qusous Ala , Jarvis Simon M. , Kerrigan Mark J.P.
Published: May 2010

Chondrocytes, the resident cell-type of articular cartilage, are responsible for the regulation of the extracellular matrix (ECM) in response to their physico-chemical environment. Due to the nature of cartilage loading, chondrocytes are exposed to constant changes in extracellular osmolality with a gradual increase throughout the day. As an increase in osmolality attenuates matrix synthesis, we have studied cell volume regulation (regulatory volume increase (RVI)) after hypertonic challenge and the regulation of RVI by the actin cytoskeleton. Using freshly isolated avian articular chondrocytes, changes in actin organisation were studied by confocal laser scanning microscopy following a 43% increase in extracellular osmolality. Using calcein-loading chondrocytes, the capacity for RVI was determined and the rate of volume recovery (t1/2) mathematically extrapolated. Following an increase in extracellular osmolality there was a significant increase (p < 0.05) in cortical actin, inhibited by the removal of extracellular calcium EGTA or by the addition of 100 µmol·L–1 gadolinium chloride. Most cells exhibited slow RVI (t1/2 = 55.5 ± 5.5 min), whereby inhibition of actin polymerisation by gadolinium chloride or the removal of extracellular calcium significantly increased the rate of volume recovery via a bumetanide-sensitive pathway (t1/2 of 29.6 ± 6.5 min and 13.8 ± 3.1 min, respectively). These data suggest the Na+–K+–2Cl– (NKCC) co-transporter regulated by the actin cytoskeleton is involved in avian chondrocyte RVI.
Plasma membrane subdomain partitioning of Lck in primary human T lymphocytes
Authors: Irles Claudine , Arias-Martinez Joel , Guzmán-Bárcenas José , Ortega Alicia
Published: May 2010

Uncovering the plasma membrane distribution of tyrosine kinase Lck is crucial to understanding T lymphocyte triggering. Several studies of Lck species partitioning have given contradictory results. We decided to re-address this point by using phospho-specific antibodies to characterize active and inactive Lck partitioning in raft and non-raft membranes from primary human peripheral blood T lymphocytes. We show that most inactive Lck was localized in rafts and was associated with nearly all CD4 coreceptors and its negative regulator Csk in resting cells, while T cell receptor (TCR) engagement promoted a sustained dephosphorylation of inactive Lck. In contrast, active Lck had a more discrete distribution interacting with only a small number of CD4 coreceptors, and the kinase showed a rapid and short phosphorylation after TCR triggering. The differences in distribution and kinetics may be related to T lymphocyte signalling threshold modulation by Lck species and suggest how TCR triggering is first initiated. This study furthers our knowledge of the TCR activation model in primary human T lymphocytes.
Cilostazol attenuates ventricular arrhythmia induction and improves defibrillation efficacy in swine
Authors: Kanlop Natnicha , Shinlapawittayatorn Krekwit , Sungnoon Rattapong , Weerateerangkul Punate , Chattipakorn Siriporn , Chattipakorn Nipon
Published: May 2010

Previous reports demonstrated that cilostazol, a phosphodiesterase 3 inhibitor, affected cellular electrophysiology and reduced episodes of ventricular fibrillation (VF) in patients with Brugada syndrome. However, its effects on VF induction and defibrillation efficacy have never been investigated. We tested the hypothesis that cilostazol increases the VF threshold (VFT) and decreases the upper limit of vulnerability (ULV) and the defibrillation threshold (DFT). A total of 48 pigs were randomly assigned to defibrillation and VF induction studies. The diastolic pacing threshold (DPT), VFT, ULV, DFT, and effective refractory period were determined before and after the infusion of cilostazol at 6 mg/kg, 3 mg/kg, or vehicle. The DPT was significantly increased after administration of 3 and 6 mg/kg cilostazol. The ULV and DFT were significantly decreased after administration of 6 mg/kg cilostazol only. The ULV in the 6 mg/kg group had 12% lower peak voltage and 25% lower total energy, and the DFT had 13% lower peak voltage and 25% lower total energy. The VFT was not altered in any experimental group. This study shows that cilostazol administration significantly increased the DPT, which was associated with significantly reduced DFT and ULV.
Effects of genistein and daidzein on erythrocyte membrane fluidity: an electron paramagnetic resonance study
Authors: Ajdžanović Vladimir , Spasojević Ivan , Filipović Branko , Šošić-Jurjević Branka , Sekulić Milka , Milošević Verica
Published: May 2010

The maintenance of erythrocyte membrane fluidity at the physiological level is an important factor affecting the ability of erythrocytes to pass through blood vessels of small luminal diameter. Genistein and daidzein, which are used as alternative therapeutics in cardiovascular conditions, can be incorporated into the cell membrane and change its fluidity. The aim of this study was to examine the effects of genistein and daidzein on erythrocyte membrane fluidity at graded depths. We used electron paramagnetic resonance (EPR) spectroscopy and fatty acid spin probes (5-DS and 12-DS) where EPR spectra were dependent on fluidity. The results showed that genistein significantly (p < 0.05) decreased erythrocyte membrane fluidity near the hydrophilic surface, while daidzein significantly (p < 0.05) increased the same parameter in deeper regions of the membrane. These data suggest that the deep fluidizing effects of daidzein on erythrocyte membranes make it a better therapeutic choice than genistein in some cardiovascular conditions.
Arecoline excites the contraction of distal colonic smooth muscle strips in rats via the M3receptor – extracellular Ca2+influx – Ca2+store release pathway
Authors: Li Chuan-Bao , Yang Xiao , Tang Wen-Bo , Liu Chuan-Yong , Xie Dong-Ping
Published: May 2010

Areca is a Chinese herbal medicine that is widely used for constipation. However the mechanisms of its action are not clear. We investigated the effects of arecoline, the most active component of areca, on the motility of rat distal colonic smooth muscle strips. In longitudinal muscle of distal colon (LMDC) and circular muscle of distal colon (CMDC), arecoline increased the contraction in a dose-dependent manner. Tetrodotoxin (TTX) did not inhibit the effects of arecoline. The contractile response to arecoline was completely antagonized by atropine. 4-Diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP) strongly depressed the response to arecoline, but gallamine and methoctramine did not. Nifedipine, 2-aminoethoxydiphenyl borate (2-APB), and Ca2+-free Krebs solution with EGTA partly inhibited the effects of arecoline. The sum of Ca2+-free Krebs solution, EGTA, and 2-APB completely inhibited the effects of arecoline. The results show that arecoline stimulates distal colonic contraction in rats via the muscarinic (M3) receptor – extracellular Ca2+influx – Ca2+store release pathway. It is likely that the action of areca in relieving constipation is due to its stimulation of muscle contraction.
TUNINGS OF PARAMETERS AND PHEROMONE UPDATE STRATEGY IN ANT COLONY OPTIMIZATION
Authors: TAMILARASI A.
Published: May 2010

Scheduling is considered to be a major task to improve the shop-floor productivity. The job shop problem is under this category and is combinatorial in nature. Research on optimization of job shop problem is one of the most significant and promising areas of optimization. This paper presents an application of the Ant Colony Optimization meta heuristic to job shop problem. The main characteristics of this model are positive feedback and distributed computation. The settings of parameter values have more influence in solving instances of job shop problem. An algorithm is introduced to improve the basic ant colony system by using a pheromone updating strategy and also to analyze the quality of the solution for different values of the parameters. In this paper, we present statistical analysis for parameter tuning and we compare the quality of obtained solutions by the proposed method with the competing algorithms given in the literature for well known benchmark problems in job shop scheduling.
Hydrogen as an Unstable Shallow Donor in Oxides
Authors: Chen Wan Ping , He Ke Feng , Wang Yu , Hu Yong Ming , Cao Jiang Li , Chan Helen Lai Wah
Published: May 2010

Hydrogen is electrochemically introduced into a monoclinic Nb2O5 in a large amount, which donates electrons to Nb5+ and decreases the resistivity of Nb2O5 by more than six orders of magnitude. Both X-ray photoelectron spectroscopy and crystal structure analyses show that ionized hydrogen, namely, proton, is not connected to an oxygen ion by a strong O–H bond, and hydrogen can be easily driven out of this oxide as molecular hydrogen by annealing at 150 °C. This finding provides a relatively direct evidence for an unstable state of a hydrogen shallow donor in oxides and should contribute much to the general understanding of hydrogen in oxides.
Solution Growth of Silicon Carbide Using Fe–Si Solvent
Authors: Yoshikawa Takeshi , Kawanishi Sakiko , Tanaka Toshihiro
Published: May 2010

In this paper, we describe the use of liquid Fe–Si alloy as the solvent for the solution growth of silicon carbide (SiC). Iron was chosen owing to the high solubility of carbon in molten iron. The crystal growth of SiC from Fe–40 mol % Si solvent on a seed crystal wafer of 6H- or 4H-SiC was carried out at 1,623–1,723 K using induction heating. The growth rate of SiC was obtained to be 90–260 µm/h. Furthermore, Raman spectroscopy revealed homo epitaxial growth on both 6H- and 4H-SiC under the experimental conditions used. Thus, the Fe–Si solvent was found to be effective for the rapid solution growth of SiC.
Linear Transmission Characteristics and Bistable Behavior of Photonic Crystal Ring Resonators with a Triangular Lattice of Air Holes
Authors: Ma Zetao , Ogusu Kazuhiko
Published: May 2010

We have studied the effect of the coupling region on the linear transmission characteristics of two types of photonic crystal ring resonator (PCRR) with a triangular lattice of air holes using reduced refractive-index coupling and three-waveguide coupling structures. The cavity mode in PCRRs working in the linear region of dispersion curves is preferable to obtain sharp resonance, which can establish traveling-wave behavior and realize one-directional dropping. In addition, we investigate the dependence of optical bistability on initial frequency detuning and input intensity. Unstable oscillations take place when detuning is large.
Investigation of Quenching Mechanism in Thermoreversible Fluorescent Recording Materials of Fluorescence Using Thermochromic Fluorescence Resonance Energy Transfer
Authors: Hirata Shuzo , Vacha Martin , Watanabe Toshiyuki
Published: May 2010

We demonstrated reversible thermosensitive recording of a fluorescent image (TRF) using a low-molecular-weight mixture consisting of a fluorescent dye, a fluoran dye, a developer, and a reversible matrix. In this material, reversible thermoresponsive disorder-crystal transition triggers a cyclical colorless-color change of a fluoran dye, which induces on–off switching of fluorescence resonance energy transfer (FRET) from a fluorescent dye to a fluoran dye. On–off switching of fluorescence is induced by heat-promoted off–on switching of FRET. Modulation of fluorescence is held at room temperature by utilizing thermal hysteresis, and nondestructive readout of the fluorescent image is accomplished in the presence of excitation light. Here, we investigate the on–off switching mechanism of fluorescence in this recording material. We analyzed the theoretical factor of emission quenching in the erasing state by comparing the theoretical overlap integral Ω between fluorescent dyes and fluoran dyes on the basis of the FRET theory with experimental emission contrast for various combinations of fluorescent dyes and fluoran dyes. It was proved that fluorescence on–off switching occurs mainly by concentration quenching due to the aggregation of fluorescent dyes and FRET from isolated fluorescent dyes to colored fluoran dyes. The key issue to obtain both high-contrast fluorescence and high fluorescence quantum yield is to control these two factors.
Optimization of Seesaw Swing Arm Actuator Design for Small Form Factor Optical Disk Drive
Authors: Chou Po-Chien , Lin Yu-Cheng , Cheng Stone
Published: May 2010

Many small form factor (SFF) optical pickup heads based on the swing arm design utilize a piezoelectric material or the slim metal plate to perform the focusing action. The seesaw-type actuator is a new mechanism used in the focusing action for SFF optical data storage devices. The swing arm nutates along a pivot instead of a hinge in the vertical movement. In this paper, an optimized design of a biaxial voice coil motor (VCM), in which the tracking and focusing VCMs are combined in the rear of the swing arm, is proposed. Simulation and experiment results demonstrate the effectiveness of the proposed design methodology by showing that the stress magnitude distribution characteristics, mechanism stiffness, and driving stability of the optimized design are enhanced in comparison with those of the original.
AC Susceptibility of Magnetic Fluid in Nonlinear Brownian Relaxation Region: Experiment and Comparison with Numerical Simulation
Authors: Yoshida Takashi , Ogawa Kotaro , Enpuku Keiji , Usuki Naoki , Kanzaki Hisao
Published: May 2010

This study investigated the AC susceptibility of magnetic fluids in the nonlinear Brownian relaxation region. The nonlinear properties of the susceptibility in high excitation fields were measured comprehensively, including the decrease in susceptibility, field-dependent Brownian relaxation time, and occurrence of the third harmonic for the susceptibility. These experimental results were compared with numerical simulations based on the Fokker–Planck equation, which describes nonlinear Brownian relaxation. We first performed the numerical simulation by assuming mono-dispersed single-domain nanoparticles. The observed nonlinear properties were shown to be roughly explained by the simulation. To compare the experiment and simulation more accurately, we then considered the size distribution of the magnetic nanoparticles existing in practical samples; this was obtained by analyzing the frequency dependence of the susceptibility in weak fields. Quantitative agreements were obtained between the experiment and simulation for the frequency and field dependences of the nonlinear susceptibility.
Short-Range Longitudinal Wake Field and Its Effect on the Energy Spectrum in a Linear Accelerator
Authors: Igo Tetsuya , Kato Ryukou , Kashiwagi Shigeru , Isoyama Goro
Published: May 2010

We have studied the effects of the wake field on the energy spectrum of a high-intensity single-bunch electron beam of 28 nC charge accelerated in an L-band accelerating structure of 1.3 GHz frequency both by experiment and by calculation. Energy spectra measured as a function of the accelerating phase show significant changes, including appearance of multiple peaks owing to the short-range longitudinal wake field. The empirical wake function is derived for the specific accelerating structure using the simulation code, ABCI. Energy spectra calculated with the wake function agree quite well with the energy spectra measured over the wide range of the accelerating phase. The effects of the wake field on the energy spectrum of the high-intensity single-bunch beam accelerated with the L-band linac at Institute of Scientific and Industrial Research (ISIR), Osaka University, are quantitatively explained in terms of the wake field theory with the empirical wake function.
Formation of Macropore and Three-Dimensional Nanorod Array in p-Type Silicon
Authors: Kim Kang-Pil , Li Shiqiang , Lyu Hong-Kun , Woo Sung-Ho , Lim Sang Kyoo , Chang Daeic , Oh Hwa Sub , Hwang Dae-Kue
Published: May 2010

We carried out a study on the change in pore wall thickness depending on the current density in p-type silicon. We attempted the formation of a uniform macropore or nanorod array with a high aspect ratio in p-type silicon by electrochemical etching through the optimization of the hydrogen fluoride (HF)/organic electrolyte composition and the design of the mask pattern. The electrochemical etching of p-type silicon in the HF: dimethylsulfoxide (DMSO): deionized (DI) water = 1:5:5 electrolyte can control the velocity of a reaction between an electrolyte and a hole necessary for the electrochemical etching of silicon through the mixing of the protic property of DI water and the aprotic property of DMSO. In this study, we fabricated a p-type silicon nanorod array of three-dimensional structures with an approximately 350 nm diameter from macroporous Si by applying two-step currents (40 mA, 200 s + 38 mA, 1600 s) to a 1.8 cm2 circular area using an optimized HF: DMSO: DI water = 1:5:5 electrolyte composition.
Physical and Electrical Properties of SiO2Layer Synthesized by Eco-Friendly Method
Authors: Kim Jong-Woong , Kim Young-Seok , Hong Sung-Jei , Hong Tae-Hwan , Han Jeong-In
Published: May 2010

SiO2thin film has a wide range of applications, including insulation layers in microelectronic devices, such as semiconductors and flat panel displays, due to its advantageous characteristics. Herein, we developed a new eco-friendly method for manufacturing SiO2nanoparticles and, thereby, SiO2paste to be used in the digital printing process for the fabrication of SiO2film. By excluding harmful Cl-and NO3-elements from the SiO2nanoparticle synthetic process, we were able to lower the heat treatment temperature for the SiO2precursor from 600 to 300 °C and the diameter of the final SiO2nanoparticles to about 14 nm. The synthesized SiO2nanoparticles were dispersed in an organic solvent with additives to make a SiO2paste for feasibility testing. The SiO2paste was printed onto a glass substrate to test the feasibility of using it for digital printing. The insulation resistance of the printed film was high enough for it to be used as an insulation layer for passivation.
Tailored Secondary Growth on Au Nanorods through Regioselective Adsorption
Authors: Kim Yeong-Joon , Song Jae Hee
Published: May 2010

Precise controlling nanostructures of nanosized metals using simple process will be very important for developing novel metal inks for printing electrodes and wires. In this paper, Au nanorods were used as seeds for the tailored secondary growth of thin shell of gold or silver by using a mild reducing agent, ascorbic acid, in the presence of cetyltrimethylammonium bromide under ambient conditions. We could tailor the secondary growth of sheathes of gold and silver on gold nanorods via regioselective adsorption on Au nanorods. Before we grew thin sheath of Au or Ag, 1,3-propanedithiol was introduced first to be regioselectively adsorbed on {111} and {100} planes of gold nanorod seeds to prevent the secondary crystal growth so that the sheath crystal could grow favorably to the direction of {110} planes of the seeds.
Organic Nano-Floating-Gate Memory with Polymer:[6,6]-Phenyl-C61 Butyric Acid Methyl Ester Composite Films
Authors: Baeg Kang-Jun , Khim Dongyoon , Kim Dong-Yu , Jung Soon-Won , Koo Jae Bon , Noh Yong-Young
Published: May 2010

Here, we report on a pentacene-based, nonvolatile transistor memory device with poly(4-vinyl phenol) (PVP):[6,6]-phenyl-C61 butyric acid methyl ester (PCBM) nano-composite films as the charge storage site. Incorporation of PCBM molecules into PVP dielectric materials as charge storage sites for electrons resulted in a reversible shift in the threshold voltage (V
Th) and reliable memory characteristics. The characteristics of the pentacene memory device were as follows: a relatively high field-effect mobility (µFET) (0.2–0.3 cm2 V-1 s-1) with a large memory window (ca. 20 V), a high on/off ratio (∼104) during writing and erasing with application of an operating gate voltage of 60 V for a short duration time (∼1 ms), and a retention time of about 40 h.
Improvement in Brightness Uniformity by Compensating for the Threshold Voltages of Both the Driving Thin-Film Transistor and the Organic Light-Emitting Diode for Active-Matrix Organic Light-Emitting Diode Displays
Authors: Fan Ching-Lin , Lai Hui-Lung , Chang Jyu-Yu
Published: May 2010

In this paper, we propose a novel pixel design and driving method for active-matrix organic light-emitting diode (AM-OLED) displays using low-temperature polycrystalline silicon thin-film transistors (LTPS-TFTs). The proposed threshold voltage compensation circuit, which comprised five transistors and two capacitors, has been verified to supply uniform output current by simulation work using the automatic integrated circuit modeling simulation program with integrated circuit emphasis (AIM-SPICE) simulator. The driving scheme of this voltage programming method includes four periods: precharging, compensation, data input, and emission. The simulated results demonstrate excellent properties such as low error rate of OLED anode voltage variation (<1%) and high output current. The proposed pixel circuit shows high immunity to the threshold voltage deviation characteristics of both the driving poly-Si TFT and the OLED.
Frequency Performance Optimization of Flexible Pentacene Rectifier by Varying the Thickness of Active Layer
Authors: Kang Chan-mo , Hong Yongtaek , Lee Changhee
Published: May 2010

We studied the thickness dependence on the high-frequency performance of pentacene-based diodes on plastic substrates. The current–voltage characteristics, forward- and reverse-bias breakdown voltages, and the frequency performance of the pentacene rectifiers were measured for diodes with the pentacene layer of various thicknesses (14, 28, 56, 84, and 104 nm) and the MoO3 buffer layer. Although the rectifier with the 56-nm-thick pentacene diode shows a highest output voltage at the low frequency, its output voltage rapidly decreases compared with others. At high frequency region up to 25 MHz, the 84-nm-thick pentacene diode shows best performance. The behavior is analyzed with the current scaling with the pentacene thickness and the frequency response of the impedance of the diode capacitance.
Restraint of Copper Oxidation Using Barrier Restoration Technique with Cu–Mn Alloy
Authors: Haneda Masaki , Ohtsuka Nobuyuki , Kudo Hiroshi , Tabira Takahiro , Sunayama Michie , Shimizu Noriyoshi , Ochimizu Hirosato , Tsukune Atsuhiro
Published: May 2010

This paper clarifies for the first time that employing Cu–Mn alloy can reduce the resistance of ultralarge scale integration (ULSI) interconnects. It is well known that Cu alloys have higher resistance than pure Cu. However, recent discussion indicates that Cu or barrier metal oxidation by moisture from interlayer dielectrics causes electrical resistance to increase even further. Therefore, Cu oxidation must be prevented. Previously, we have reported a barrier restoration technique using Cu–Mn alloy, and the application of this technique is expected to result in strong tolerance to Cu oxidation. In this work, we investigated the property that copper is protected from oxidation when using the barrier restoration technique with Cu–Mn alloy. This property results in the reduction of interconnect resistance and the improvement of the resistance distribution in ULSI interconnects. We conclude that using the barrier restoration technique with Cu–Mn alloy will be being compatible with further scaling to 22 nm node and beyond.
Reactively Sputtered Nanocrystalline ZrN Film as Extremely Thin Diffusion Barrier between Cu and SiO2
Authors: Takeyama Mayumi B. , Sato Masaru , Aoyagi Eiji , Noya Atsushi
Published: May 2010

The results of analyses by X-ray diffraction, transmission electron microscopy, and grazing incidence X-ray reflectivity measurement indicate that a 5-nm-thick ZrN film interposed between Cu and SiO2 shows excellent barrier properties, tolerating annealing up to at least 500 °C for 30 min. The X-ray diffraction pattern reveals a decrease in the intensity of the Cu(111) reflection upon annealing at 800 °C, suggesting a failure of the thin barrier due to Cu diffusion through the barrier. We are confident that the formation of a continuous nanocrystalline ZrN film in a uniform fashion in a stable phase with a slightly nitrogen-rich composition is a cause of the excellent features obtained. The formation process of the ZrN film is discussed in terms of the nucleation process of reactive sputtering at a low deposition temperature.
End-Point Detection of Ta/TaN Chemical Mechanical Planarization via Forces Analysis
Authors: Sampurno Yasa , Gu Xun , Nemoto Takenao , Zhuang Yun , Teramoto Akinobu , Philipossian Ara , Ohmi Tadahiro
Published: May 2010

This study explores the transition of shear force spectral fingerprints during tantalum (Ta) and/or tantalum nitride (TaN) chemical mechanical planarization on patterned wafers using a polisher and tribometer that has the unique ability to measure shear force and down force in real-time. Fast Fourier Transformation is performed to convert the raw force data from time domain to frequency domain and to illustrate the amplitude distribution of shear force and down force. Results show that coefficient of friction, variance of shear force and variance of down force increase during polishing when the Ta/TaN layer is removed thus exposing the inter-layer dielectric layer. Unique and consistent spectral fingerprints are generated from shear force data showing significant changes in several fundamental peaks before, during and after Ta/TaN clearing. Results show that a combination of unique spectral fingerprinting, coefficient of friction and analysis of force variance can be used to monitor in real-time the polishing progress during Ta/TaN chemical mechanical planarization for optimal polishing time.
Effect of Pattern Layout and Dissolved Oxygen in CO2 Rinse Water on Cu Corrosion during Post-Etch Cleaning
Authors: Tokuri Kentaro , Yamashita Yukinari , Shiohara Morio , Oda Noriaki , Kondo Seiichi , Saito Shuichi
Published: May 2010

When post-etch cleaning was carried out in Cu dual-damascene process, Cu at the bottom of isolated via was etched out especially in the wafer edge, and this would become a critical issue as device scale is shrunk. The corrosion was caused in the rinse step rather than chemical cleaning step because dissolved oxygen in rinse water from the air increased oxidation–reduction potential (ORP) and CO2 included in the rinse water for preventing wafer electrification decreased pH. The corrosion was found to be suppressed by increasing dummy pattern density and by controlling atmosphere and pH of the rinse water.
Radio Frequency Micro Electro Mechanical Systems Inductor Configurations for Achieving Large Inductance Variations and High Q-factors
Authors: Mizuochi Yutaka , Amakawa Shuhei , Ishihara Noboru , Masu Kazuya
Published: May 2010

To determine a micro electro mechanical systems (MEMS) inductor configuration that gives large inductance variations and high Q-factors, air-suspended MEMS inductor configurations are studied: (a) an inductor with two angularly meandered lines, (b) a solenoid inductor with a pair of movable shields, (c) a planar spiral inductor with a patterned shield of different areas, and (d) a planar spiral inductor with a metallic frame of different sizes. The configuration of (a) is shown to give a large inductance variation of 115%. However, its Q-factor is only about 10, and difficulties in fabrication are also expected. The configuration of (b) could be a reasonable engineering solution. The inductance variation is 67%, and the maximum Q-factor is over 22. The solenoidal inductor configuration is thus considered suitable for realizing an RF MEMS variable inductor with large inductance variations and high Q-factors.
Repeated phlebotomy augments angiogenesis to improve blood flow in murine ischemic legs
Authors: Kawamura Itta , Takemura Genzou , Kanamori Hiromitsu , Takeyama Toshiaki , Kawaguchi Tomonori , Tsujimoto Akiko , Goto Kazuko , Maruyama Rumi , Watanabe Takatomo , Shiraki Takeru , Aoyama Takuma , Fujiwara Takako , Fujiwara Hisayoshi , Minatoguchi Shinya
Published: May 2010

Anemia may accelerate angiogenesis in ischemic organs through its ability to augment tissue hypoxia-induced generation of several known angiogenic factors and to increase erythropoietin levels, which are also potently angiogenic. We examined the effect of controlled phlebotomy (bloodletting) on blood flow in a mouse ischemic leg model. We ligated the right femoral artery of BALB/c mice. In the phlebotomy group, 200 μl of blood were drawn from the tail vein once a week. After 4 wk, blood flow in the ischemic leg was significantly better in the phlebotomy group (flow ratio of the ischemic to nonischemic leg, 0.87 ± 0.04) than the control group (0.59 ± 0.05, P < 0.05), and capillary density was significantly higher. Repeated phlebotomy increased serum erythropoietin levels as well as the expression of hypoxia-inducible transcription factor-1α and vascular endothelial growth factor and both the expression and activity of Akt and endothelial nitric oxide synthase (eNOS) in ischemic legs. Treatment with wortmannin or Nω-nitro-l-arginine methyl ester significantly attenuated the phlebotomy-induced improvement of blood flow. In addition, fluorescence-activated cell sorting analysis revealed an increase in circulating peripheral endothelial progenitor cells in the phlebotomy group, and treatment with AMD3100, a specific inhibitor of the chemokine receptor CXCR4, blocked the beneficial effect of phlebotomy. These findings suggest that repeated phlebotomy improves blood flow in ischemic legs through an angiogenic action that involves the Akt/eNOS pathway, endothelial progenitor cell mobilization, and their complicated cross talk. An adequately controlled phlebotomy might be one method by which to induce therapeutic angiogenesis.
Integrated analysis of atrioventricular interactions in tetralogy of Fallot
Authors: Riesenkampff Eugénie , Mengelkamp Lena , Mueller Matthias , Kropf Siegfried , Abdul-Khaliq Hashim , Sarikouch Samir , Beerbaum Philipp , Hetzer Roland , Steendijk Paul , Berger Felix , Kuehne Titus
Published: May 2010

The atria play an important role in cardiac performance. We evaluated their function and the atrioventricular interaction in operated patients with tetralogy of Fallot (TOF). Twenty patients who had undergone surgical repair of TOF and seven controls were investigated. Patients had residual pulmonary but no major tricuspid valve insufficiency. Atrial and ventricular strain rates were obtained by echocardiographic speckle tracking. Cine MRI-derived volumetric analysis provided atrial and ventricular time volume and time volume change curves yielding emptying and filling parameters. In addition, at the atrial level, reservoir, conduit and pump function, and cyclic volume change were calculated. At the atrioventricular valve level, tricuspid and mitral annular plane systolic excursion (TAPSE and MAPSE, respectively) were measured by two-dimensional echocardiography. In the patients compared with controls, right ventricular end-diastolic volumes were increased and biventricular ejection fraction was decreased (all P < 0.05). Biventricular measures of early diastolic ventricular filling were at control levels, but in late diastole, right ventricular filling parameters and strain rates were decreased ( P < 0.001). The maximal right atrial size was slightly but not significantly diminished, but cyclic volume change was significantly reduced ( P < 0.0001). Pump and reservoir function were decreased ( P < 0.05), and conduit function was elevated ( P < 0.001). The left atrium showed reduced reservoir function and cyclic volume change ( P < 0.05). TAPSE and MAPSE were also decreased ( P < 0.05). There were statistically significant interdependencies between RV ejection fraction, TAPSE, and right atrial filling and emptying parameters (all P < 0.05). In TOF patients, moderate systolic and diastolic right ventricular dysfunction is associated with clearly impaired right atrial function. The left atrium is affected to a lesser extent.
Reduced in vivo high-energy phosphates precede Adriamycin-induced cardiac dysfunction
Authors: Maslov M. Y. , Chacko V. P. , Hirsch G. A. , Akki A. , Leppo M. K. , Steenbergen C. , Weiss R. G.
Published: May 2010

Adriamycin (ADR) is an established, life-saving antineoplastic agent, the use of which is often limited by cardiotoxicity. ADR-induced cardiomyopathy is often accompanied by depressed myocardial high-energy phosphate (HEP) metabolism. Impaired HEP metabolism has been suggested as a potential mechanism of ADR cardiomyopathy, in which case the bioenergetic decline should precede left ventricular (LV) dysfunction. We tested the hypothesis that murine cardiac energetics decrease before LV dysfunction following ADR (5 mg/kg ip, weekly, 5 injections) in the mouse. As a result, the mean myocardial phosphocreatine-to-ATP ratio (PCr/ATP) by spatially localized31P magnetic resonance spectroscopy decreased at 6 wk after first ADR injection (1.79 ± 0.18 vs. 1.39 ± 0.30, means ± SD, control vs. ADR, respectively, P < 0.05) when indices of systolic and diastolic function by magnetic resonance imaging were unchanged from control values. At 8 wk, lower PCr/ATP was accompanied by a reduction in ejection fraction (67.3 ± 3.9 vs. 55.9 ± 4.2%, control vs. ADR, respectively, P < 0.002) and peak filling rate (0.56 ± 0.12 vs. 0.30 ± 0.13 μl/ms, control vs. ADR, respectively, P < 0.01). PCr/ATP correlated with peak filling rate and ejection fraction, suggesting a relationship between cardiac energetics and both LV systolic and diastolic dysfunction. In conclusion, myocardial in vivo HEP metabolism is impaired following ADR administration, occurring before systolic or diastolic abnormalities and in proportion to the extent of eventual contractile abnormalities. These observations are consistent with the hypothesis that impaired HEP metabolism contributes to ADR-induced myocardial dysfunction.
GABAergic Interneurons in the Mouse Lateral Amygdala: A Classification Study
Authors: Sosulina Ludmila , Graebenitz Stéphanie , Pape Hans-Christian
Published: May 2010

Whole cell patch-clamp recordings were performed in GABAergic interneurons labeled by green fluorescent protein (GFP) in the lateral amygdala (LA) in vitro from glutamic acid decarboxylase 67 (GAD67)-GFP mice. Neurons were characterized by electrotonic and electrogenic parameters. Cytoplasm was collected from individual neurons, and single-cell RT-PCR was used for detection of molecular markers typifying LA interneurons. Hierarchical cluster and multiple discriminant analysis demonstrated the existence of five types of GABAergic interneurons, which can be reliably identified through electrophysiological criteria. Action potentials were of a short duration followed by pronounced fast afterhyperpolarization (AHP) in interneurons of all types, except for type V, which generated broad action potentials and displayed typical spike bursts at the beginning of depolarizing stimuli and prominent anomalous inward rectification. Interneurons of type I and II generated series of action potentials with frequency adaptation on maintained depolarizing current stimulation with overall frequencies at high levels and presented delayed firing, stuttering or fast-spiking behavior. Further distinguishing features of type II interneurons were a medium AHP following spike trains and pronounced anomalous inward rectification. Types III and IV of neurons fired regularly, whereas type IV displayed no prominent spike frequency adaptation. Additionally, interneurons of all five types contained mRNA of glutamic acid decarboxylase 65 and cholecystokinin, whereas only type I interneurons were somatostatin-positive. Overall, these data represent a detailed and reliable classification scheme of LA GABAergic interneurons and will provide a feasible basis for subsequent functional studies.