Dislocation structures introduced by high-speed deformation in bcc metals

Systematic experiments were carried out over a wide range of strain rate, 10⁰–10⁶ s⁻¹, so as to reveal the deformation mode in bcc crystals, especially at high strain rate. Dislocation structure showed heterogeneous distribution at low strain rates in all three bcc metals examined. At higher strain rates exceeding 10³ s⁻¹, distribution of dislocations was random, and the formation of small dislocation loops was observed in V and Nb. In Mo, small dislocation loops were not formed by deformation, even at high strain rates. However, post-deformation annealing of an Mo specimen that had been deformed by 20% at 5×10⁵ s⁻¹ produced dislocation loops. The inside–outside contrast method identified these loops to be of vacancy type. These results reveal that in Mo vacancy clusters are not formed directly from the interaction of dislocations, but by the aggregation of vacancies. In V and Nb, the same formation process is believed to occur at high strain rates. These results suggest that the different mode of plastic deformation at high strain rates accompanied by production of vacancies also occurred in bcc metals.     

Dynamics of Vortex Lattice Formation in a Rotating Bose-Einstein Condensate with an Optical Lattice Potential

We study dynamics of quantized vortex lattice formation in a rotating Bose-Einstein condensate with a square blue-detuned optical lattice by solving the Gross-Pitaevskii equation. This dynamics depends on the depth of the optical lattice. Vortices tend to form a triangular lattice under the rotation, while an optical lattice likes to pin vortices at their peaks. Such a competition of two effects makes this system more interesting and complicated.     

Effect of the atmosphere on chemical composition and electrochemical properties of solid electrolyte interface on electrodeposited Li metal

Many efforts have been paid to realize the superior anodes for future Li batteries in either the dry Ar atmosphere or the dry air atmosphere. In this work, in order to clarify the effects of such atmospheres, the most reactive anodes of Li were freshly electrodeposited under the dry Ar or under the dry air condition. The Solid Electrolyte Interface (SEI) formed during the electrodeposition of Li anodes is revealed to have a different chemical composition and protective feature. The Li deposited under the dry air was revealed to have longer cycle life in the electrolyte than that deposited in Ar, even in the electrolyte containing ionic liquid. From the XPS results, the SEI formed in dry air is proved to be different from that formed in Ar gas atmospheres, that is, the SEI formed in dry air consists of Li₂CO₃ and Li nitride. In order to improve the performance of the anodes, the atmosphere for the initial preparation of the anode/electrolyte interface should be tuned.     

Near-infrared combination and overtone bands of the CH2 sequence in CH2X2, CH2XCHX2, and CH3(CH2)5CH3 and their characteristic frequency zones

We characterized near-infrared spectra of the CH2 sequence in CH2X2 (X=halogen), CH2ClCHCl2, and CH3(CH2)5CH3. Each near-infrared absorption in the region from 3500 to 10,000 cm-1 is consistently assigned to one of the five different combination or overtone groups, in the order of increasing frequency, of the {[v(CH)]+[delta(CH)]} (A), {[v(CH)]+[2delta(CH)]} (B), [2v(CH)] (C), {[2v(CH)]+[delta(CH)]} (D), and [3v(CH)] (E) types, where v(CH) and delta(CH) denote the CH stretching and CH deformation normal modes, respectively. Each group has its own characteristic frequency zone. The bands of B, D, and E, which are second-order combinations or overtones, are weaker by 1/10-1/50 than those of A and C, which are first-order combinations or overtones. The near-infrared spectra of the CH2 sequence show "window zones" of very weak or no absorptions. This suggests that we can perceive the characteristic near-infrared bands of a functional group through the window zones, and we give an example to demonstrate this. The first-order combination bands of type A only of CH2X2 are reasonably assigned to a pair of the normal modes of v(CH) and delta(CH). From this we predict that the first-order combination bands should give structural information on the CH2 chain, similar to the infrared fundamental bands.     

A high pressure shock tube study of n-propylbenzene oxidation and its comparison with n-butylbenzene

Ignition delay times have been measured for mixtures of n-propylbenzene in air (≈21% O₂, ≈79% N₂) at equivalence ratios of 0.29, 0.48, 0.96 and 1.92 and at reflected shock pressures of 1, 10 and 30 atm in a heated high-pressure shock tube over a wide temperature range (1000–1600 K). The effects of reflected shock pressure and of equivalence ratio on ignition delay time were determined and common trends highlighted. Simulations were carried out using the n-propylbenzene sub-mechanism contained in an n-butylbenzene reaction mechanism available in the literature. This kinetic model was improved by including pressure dependent reactions which were not in place previously and the addition of the NUI Galway C₀–C₄ sub-mechanism. These simulations showed very good agreement with the experimental data. Additionally a comparison is made with experimental data previously obtained and published for n-butylbenzene over the same range of conditions and common trends are highlighted.     

Influences of the electron donor groups on the properties of thiophene-(N-aryl)pyrrole-thiophene-based organic sensitizers

In this study, 1-(2,6-diisopropylphenyl)-2,5-di(2-thienyl)pyrrole-based metal-free organic dyes containing three different non planar electron donor groups such as methoxy or hexyloxy substituted triphenylamine and difluorenephenylamine were prepared in order to see the effect of electron donor groups on the opto-electrical properties and applied in dye-sensitized solar cells (DSSC). All three dyes showed broad absorption band in visible part of the solar spectrum (∼300 nm–600 nm). The dye (TPTDYE-3) containing sterically less hindered methoxy substituted triphenylamine was found to show relatively red shifted absorption compared to that of the dye (TPTDYE-4) containing hexyloxy substituted triphenylamine or the dye (TPTDYE-5) containing difluorenephenylamine. The optical band gaps of the three dyes were calculated to be 2.19 eV, 2.22 eV and 2.24 eV, respectively, and the highest occupied molecular orbital (HOMO) energy levels of the three dyes were found to be located at 0.65 V, 0.68 V and 0.75 V, respectively. The DSSC performance of each dye was investigated with and without coadsorbent. The maximum solar to electrical energy conversion efficiencies (η) of the DSSCs made from only sensitizer were 4.18%, 5.28% and 5.42% while those of the DSSCs made from sensitizer with coadsorbent were 5.47%, 5.58% and 5.63%, respectively.     

α-Amylase immobilization capacities of mesoporous silicas with different morphologies and surface properties

α-Amylase was encapsulated in several mesoporous materials (folded sheet mesoporous silica (FSM), cubic mesoporous silica (KIT-6), and two-dimensional hexagonal mesoporous silica (SBA-15)) that differed morphologically in terms of particle shape, pore size, and pore structure. The encapsulation capacity and thermal stability of encapsulated α-amylase were examined. The amount of α-amylase encapsulated increased with increasing pore size in the following order: SBA-15 < KIT-6 < FSM. Nitrogen adsorption experiments were performed before and after α-amylase encapsulation in mesoporous silicas with pore sizes larger than the size of α-amylase, confirming that α-amylase was encapsulated in the pores. Among mesoporous silicas with similar pore sizes, FSM was found to have the highest capacity for α-amylase encapsulation both per weight and per surface area of silica. Furthermore, α-amylase encapsulated in FSM demonstrated high thermal stability at 90 °C relative to the thermal stability of free α-amylase or free α-amylase encapsulated in other mesoporous silicas. Zeta potential measurements showed that the FSM surface had an isoelectric point that was lower than that of other mesoporous silicas, and hydrophilicity measurements showed that its surface was more hydrophilic. The surface properties of FSM contributed to the high thermal stability of the α-amylase encapsulated within the pores.     

Immobilization of cholesterol oxidase in LbL films and detection of cholesterol using ac measurements

The preserved activity of immobilized biomolecules in layer-by-layer (LbL) films can be exploited in various applications, including biosensing. In this study, cholesterol oxidase (COX) layers were alternated with layers of poly(allylamine hydrochloride) (PAH) in LbL films whose morphology was investigated with atomic force microscopy (AFM). The adsorption kinetics of COX layers comprised two regimes, a fast, first-order kinetics process followed by a slow process fitted with a Johnson–Mehl–Avrami (JMA) function, with exponent ~ 2 characteristic of aggregates growing as disks. The concept based on the use of sensor arrays to increase sensitivity, widely employed in electronic tongues, was extended to biosensing with impedance spectroscopy measurements. Using three sensing units, made of LbL films of PAH/COX and PAH/PVS (polyvinyl sulfonic acid) and a bare gold interdigitated electrode, we were able to detect cholesterol in aqueous solutions down to the 10^? 6 M level. This high sensitivity is attributed to the molecular-recognition interaction between COX and cholesterol, and opens the way for clinical tests to be made with low cost, fast experimental procedures.     

Taurine accelerates the regression of hypercholesterolemia in stroke-prone spontaneously hypertensive rats

The effects of taurine on the regression of pre-established hypercholesterolemia were examined in stroke-prone spontaneously hypertensive rats (SHRSP). Hypercholesterolemia was induced by feeding a hypercholesterolemic diet to SHRSP for 30 days. Then, the diet was switched to normal chow with or without 3% taurine, and the effects were followed up for another 30 days. During regression serum cholesterol level was rapidly decreased, and was accelerated by taurine. A similar accelerated decrease in cholesterol content by taurine was seen also in tissues including the liver, intestine, and aorta. In the liver, acyl-CoA:cholesterol acyltransferase (ACAT) activity was significantly low in the taurine-supplemented group, parallel with the hepatic cholesteryl ester content. On the other hand, hepatic cholesterol 7 alpha-hydoxylase activity maintained a higher level in the taurine-supplemented group. These results showed that taurine accelerates the regression of hypercholesterolemia, and suggested that this effect is related to the increase in cholesterol catabolism to bile acid through the enhancement of 7 alpha-hydoxylase activity.     

Molecular typing of methicillin-resistant Staphylococcus aureus by polymerase chain reaction: distribution of the typed strains in hospitals

Management of the neuropathic bowel is one of the major issues in the treatment of patients with severe spinal cord injury (SCI). Pulsed irrigation evacuation (PIE) has been evaluated in several small studies for the clearing of fecal impactions in patients with a neuropathic bowel. We evaluated our experience with 398 PIE procedures performed on inpatients and outpatients at our facility. It has proven to be both safe and effective in a wide variety of patients with this disorder, and is a useful addition to traditional methods in the management of the neuropathic bowel.