Dye-sensitized solar cell based on nanocrystalline TiO<Subscript>2</Subscript> with 3–10 nm in diameter

Nanocrystalline TiO₂ with 3–10 nm in diameter was prepared with a surfactant-template method. Dye-sensitized solar cells were assembled using the prepared nanocrystalline TiO₂ with large surface area and high crystallinity, which achieved significant higher Jsc when compared to cells fabricated with bigger particles of 25 nm in diameter. In the cells with nanocrystalline TiO₂, the sintering temperature drastically affected the conversion performance of the cells.     

Three-dimensional display of the bronchi using helical CT

The purpose of this study was to evaluate the clinical usefulness of three-dimensional (3D) images of the bronchi obtained using helical CT. Thirteen patients with lung cancer, one with tracheal diverticulum, and one with bronchial amyloidosis were examined. The CT scanner employed was the Toshiba Xforce. The helical CT scan cycle consisted of 20 continuous rotations, each requiring 1.5 sec, for a total scanning time of 30 sec. Scans were obtained using a 5-mm X-ray beam width, a 5-mm/1.5 sec couchtop sliding speed, and a 2-mm reconstruction interval. 3D images were reconstructed using a CEMAX VIPstation. The optimal lower and upper threshold CT values for 3D images of the bronchi were -650 and -100 HU, respectively, and 3D images clearly depicted endobronchial lesions. Cartilage crescents were also demonstrated, but longitudinal and circular mucosal folds could not be visualized. In conclusion, 3D images of the bronchi acquired using helical CT were useful in evaluating endobronchial lesions.     

Induced-fit association between DNA and esperamicin. Importance of structural flexibility in host DNA duplex

In this study, a series of synthetic oligonucleotide duplexes are tested as a substrate for esperamicin. The duplexes contain a typical binding sequence of esperamicin, 5'-GGA/TCC, but have different flexibilities in helix structure from each other. When cleavage activities of these oligonucleotides by esperamicin were estimated by using DNA sequencing method, a substantial increase of the cleavage at 3'-NAGG was observed with increasing the helix flexibility. This observation indicates that structural flexibility of host DNA duplex is important in an induced-fit association between esperamicin and DNA.     

Improvement in Thermoelectric Characteristics of n-type Iron Disilicide by Local Composition Modification

High thermoelectric figure of merit semiconducting ceramics of n -type iron disilicide with modified local compositions have been developed. Sintering and annealing of the composite powder composed of iron disilicide and precipitated cobalt (II) hydroxide resulted in the dissolution of excess Co and oxygen into the iron disilicide phase. Excess Co segregated to the grain boundary region, while interstitially incorporated oxygen was distributed homogeneously in the microstructure. The maximum figure of merit achieved was 5.2 × 10⁻⁴/K at 673 K.     

Hydrophobic effects on protein/nucleic acid interaction: enhancement of substrate binding by mutating tyrosine 45 to tryptophan in ribonuclease Tl

Hydrophobic effects on binding of ribonuclease Tl to guaninebases of several ribonucleotides have been proved by mutatinga hydrophobic residue at the recognition site and by measuringthe effect on binding. Mutation of a hydrophobic surface residueto a more hydrophobic residue (Tyr45 – Trp) enhances thebinding to ribonucleotides, including mononucleotide inhibitorand product, and a synthetic substrate-analog trinudeotide aswell as the binding to dinucleotide substrates and RNA. Enhancementson binding to non-substrate ribonucleotides by the mutationhave been observed with free energy changes ranging from –2.2 to – 3 .9 kJ/mol. These changes are in good agreementwith that of substrate binding, –2.3 kJ/mol, which iscalculated from Michaelis constants obtained from kinetic studies.It is shown, by comparing the observed and calculated changesin binding free energy with differences in the observed transferfree energy changes of the amino acid side chains from organicsolvents to water, that the enhancement observed on guaninebinding comes from the difference in the hydrophobic effectsof the side chains of tyrosine and tryptophan. Furthermore,a linear relationship between nucleolytic activities and hydrophobicityof the residues (Ala, Phe, Tyr, Trp) at position 45 is observed.The mutation could not change substantially the base specificityof RNase Tl, which exhibits a prime requirement for guaninebases of substrates.     

表面活性剂辅助水热法中TiO2的形状控制

By hydrolysing titanium isopropoxide in a long hydrocarbon chain surfactant-containing solution, TiO2 fine particles with a diversity of well-defined morphologies was synthesized in this study by a hydrothermal route. The structural change during the formation process was monitored by scanning electron microscopy, transmission electron microscopy and X-ray diffraction analysis. TiO2 with various morphologies such as particle, sheet, rod, tube and flower-like shape was obtained by carefully controlling the preparation conditions. The experimental results show that the pH value is crucial for shape control of the produced TiO2 because it can change the charge state of the surfactant in the solution and the adsorption potential of the surfactant on the TiO2 surface. The shape evolvement of anatase TiO2 was elucidated by quenching the reaction at different stage and the formation mechanism of different shaped TiO2 was suggested.     

Non‐destructive evaluation of fatigue damage and fatigue crack initiation in type 316 stainless steel by positron annihilation line‐shape and lifetime analyses

Rotating bending fatigue tests were conducted using type 316 stainless steel. The fatigue tests were periodically terminated, and fatigue damage and fatigue crack initiation were non‐destructively and sequentially evaluated by positron annihilation line‐shape and lifetime analyses. The counter‐jig and anticoincidence methods were used for positron annihilation line‐shape and lifetime analyses, respectively, to enhance the analytical precision. The fatigue crack lengths were monitored by a plastic replication technique, and related to the parameters in both analyses. S‐parameter obtained in the line‐shape analysis increased with increasing fatigue damage, while it was difficult to detect fatigue crack initiation and subsequent small fatigue crack growth. That was because the precision of line‐shape analysis was limited. On the other hand, both fatigue damage and fatigue crack initiation were successfully detected by lifetime analysis. Positron annihilation lifetime also increased with increasing fatigue damage, and lifetime was longer at the notch root with fatigue crack than at the smooth section without crack. It was considered that the precision of lifetime analysis was high enough to detect high dislocation density areas at the fatigue crack tips.     

Survival of Salmonella Enteritidis PT 30 on inoculated almond kernels in hot water treatments

Almonds are blanched by exposure to hot water or steam-injected water to remove the pellicle (skin) from the kernel. This study evaluated the survival of Salmonella Enteritidis PT 30, Salmonella Senftenberg 775W and Enterococcus faecalis on whole raw almond kernels exposed to hot water. Whole, inoculated (7 to 9 log CFU/g) Nonpareil almonds (40 g) were submerged in 25 L of water maintained at 60, 70, 80 and 88 °C. Almonds were heated for up to 12 min, drained for 2 s, and transferred to 80 mL of cold (4 °C) tryptic soy broth. Almonds in broth were stomached at high speed for 2 min, serially diluted, plated onto tryptic soy and bismuth sulfite agars (Salmonella) or bile esculin agar (Enterococcus) and incubated at 37 °C for 24 and 48 h, respectively. D values of 2.6, 1.2, 0.75 and 0.39 min were calculated for exposure of S. Enteritidis PT 30 to water at 60, 70, 80 and 88 °C, respectively; the calculated z value was 35 C°. D values determined for Salmonella Senftenberg 775W and E. faecalis at 88 °C were 0.37 and 0.36 min, respectively. Neither Salmonella serovar could be recovered by enrichment of 1-g samples after almonds inoculated at 5 log CFU/g were heated at 88 °C for 2 min. These data will be useful to validate almond industry blanching processes.     

Observation of non-chemical equilibrium effect on Ar-CO2-H2 thermal plasma model by changing pressure

The authors developed a two-dimensional one-temperature chemical non-equilibrium (1T-NCE) model of Ar-CO₂-H₂ inductively coupled thermal plasmas (ICTP) to investigate the effect of pressure variation. The basic concept of one-temperature model is the assumption and treatment of the same energy conservation equation for electrons and heavy particles. The energy conservation equations consider reaction heat effects and energy transfer among the species produced as well as enthalpy flow resulting from diffusion. Assuming twenty two (22) different particles in this model and by solving mass conservation equations for each particle, considering diffusion, convection and net production terms resulting from hundred and ninety eight (198) chemical reactions, chemical non-equilibrium effects were taken into account. Transport and thermodynamic properties of Ar-CO₂-H₂ thermal plasmas were self-consistently calculated using the first-order approximation of the Chapman-Enskog method. Finally results obtained at atmospheric pressure (760 Torr) and at reduced pressure (500, 300 Torr) were compared with results from one-temperature chemical equilibrium (1T-CE) model. And of course, this comparison supported discussion of chemical non-equilibrium effects in the inductively coupled thermal plasmas (ICTP).     

Optical matching of a slowly extracted beam with transport line

In order to define the optical parameters of a slowly extracted beam at the entrance of the extraction channel and to realize optical matching with the beam line, the outgoing separatrix was measured at HIMAC. Modifying the lattice parameters of the ring model according to the measurement result, the simulation result makes it possible to predict the optical parameters at the extraction channel. As a result, it was experimentally verified that optical matching of the slowly extracted beam with the transport line was realized. The measured beam size and dispersion functions were in good agreement with the calculation result at each monitor in the transport line. Particle tracking also predicts the beam profile at each profile monitor in the beam line. Further, a quasi-parallel beam was demonstrated by changing the beam optics in the beam line.