Two-dimensional crystal growth of thermally converted organic semiconductors at the surface of ionic liquid and high-mobility organic field-effect transistors

We report a novel solution-crystallization method to grow two-dimensional platelet-shaped single-crystals of well-known insoluble organic semiconductors via thermal conversion of their precursor molecules dissolved in ionic liquids (ILs). By optimizing conditions of the crystal growth regarding physical properties of ILs such as density and viscosity, we successfully and reproducibly obtained thin platelets of pentacene and dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (DNTT) single-crystals, with which nearly the best performing field-effect transistors are constructed for the two compounds. The prompt and simple technique has opened the way to use practically insoluble organic semiconductor materials for high-performance printed electronics, which enables mass-producible and large-area organic circuitry devices.     

Medical cuneiform fracture-dislocation associated with medial and intermediate cuneiform fractures

We report the microbiological characteristics of two Rahnella aquatilis strains isolated in the faeces of two patients with acute gastroenteritis, one of whom is an AIDS patient. The biochemical behaviour was studied with different automated identification systems, and the few clinical cases to be found in the literature were reviewed. Of the nine strains isolated in clinical samples, two were obtained from blood cultures, two from respiratory samples, one from urine, one from a burn wound, one from a surgical wound, and two (our strains) from faeces. In almost all cases the patient presented an underlying condition facilitating infection by opportunistic microorganisms. The majority of strains are characterized by their resistance to ampicillin, cephalothin and cefoxitin. Due to the rarity of the isolation of R. aquatilis in human samples it is not yet possible to establish, with any degree of certainty, its true pathogenic capacity.     

Mechanisms and mechanics of early growth of debonding crack in an APSed Ni-base superalloy TBCs under cyclic load

Nucleation and early growth of debonding cracks in a Ni-based superalloy thermal barrier coating (TBC) system were investigated. The TBC system consisting of CoNiCrAlY bond and ZrO₂ top coat stabilized by 8%Y₂O₃, was subjected to cyclic load at high temperature. During the study, special effort was made to understand both mechanistic and mechanical behavior on the nucleation and subsequent crack propagation process. The experimental observations clearly demonstrated that both the lamellar structure of top coat and the interlamellar cracks at the splat boundaries played intrinsic role in the nucleation of the spallation cracks. It was also shown that the naturally-initiated small spallation cracks in the smooth specimen revealed propagation rates considerably higher than long crack in the notched specimen under the same remote external loading conditions. This behavior reminds us the fatigue small crack problems, same as in metallic materials. Some fracture mechanics aspects of these characteristics and behaviors are discussed on the basis of FEM calculations.     

An azide-insensitive superoxide dismutase from a hyperthermophilic archaeon, Sulfolobus solfataricus

We studied the mechanisms by which the plant alkaloid tetrandrine (TTD) inhibits Mac-1-dependent neutrophil adhesion to fibrinogen. TTD (0.1-10 microM) significantly inhibited Mac-1 up-regulation and neutrophil adhesion, as induced by N-formyl-methionyl-leucyl-phenylalanine (fMLP) or phorbol-myristate-acetate (PMA). Treatment of neutrophils with fMLP or PMA caused a rapid influx of Ca++ and accumulation of reactive oxygen species (ROS), both of which have been shown to enhance neutrophil adhesion via Mac-1 up-regulation. Because TTD antagonizes Ca++ influx and abrogates ROS, we examined the relationship between Ca++ influx, ROS formation, and Mac-1 expression in TTD-inhibited neutrophil adhesion. TTD alone caused a slight but statistically significant increase in [Ca++]i with no effect on adhesion. In contrast, TTD as well as two Ca++ channel antagonists, verapamil and nifedipine, markedly diminished fMLP- and PMA-induced Ca++ influx, Mac-1 up-regulation, and adhesion. TTD also inhibited increases in [Ca++]i and adhesion induced by the ionophore A23187 but failed to inhibit those induced by thapsigargin, an agent mobilizing Ca++ from intracellular stores. Thus, TTD impeded Ca++ influx from outward to avert neutrophil adhesion. Similarly, TTD and two ROS scavengers, superoxide dismutase and catalase, abolished ROS production, Mac-1 up-regulation, and neutrophil adhesion. Ca++ and ROS, therefore, represent two essential signals for Mac-1 up-regulation upon fMLP or PMA stimulation. Our data suggest that the antiadherent effect of TTD is mediated, in part, by the inhibition of Ca++ influx and ROS formation, resulting in suppressed up-regulation of Mac-1 and, in turn, neutrophil adhesion to fibrinogen.     

Study on premixing phase of steam explosion at JAERI

Melt jet breakup and fragmentation has been studied in ALPHA program at JAERI. In the first two experiments of the MJB series, a jet of molten lead–bismuth eutectic alloy was released into a deep pool of saturated water. The steam generation rate was measured and correlated with the jet behavior observed by a high-speed camera. The jet breakup length and debris size distribution were also evaluated. In parallel with the experimental study, JASMINE code has been developed for the simulation of a steam explosion process. The models of melt jet breakup and the particle breakup in the code were assessed by analyzing FARO-L14 and ALPHA MJB experiments.     

Bioengineered Silkworm for Producing Cocoons with High Fibroin Content for Regenerated Fibroin Biomaterial-Based Applications

Silk fibroin exhibits high biocompatibility and biodegradability, making it a versatile biomaterial for medical applications. However, contaminated silkworm-derived substances in remnant sericin from the filature and degumming process can result in undesired immune reactions and silk allergy, limiting the widespread use of fibroin. Here, we established transgenic silkworms with modified middle silk glands, in which sericin expression was repressed by the ectopic expression of cabbage butterfly-derived cytotoxin pierisin-1A, to produce cocoons composed solely of fibroin. Intact, nondegraded fibroin can be prepared from the transgenic cocoons without the need for sericin removal by the filature and degumming steps that cause fibroin degradation. A wide-angle X-ray diffraction analysis revealed low crystallinity in the transgenic cocoons. However, nondegraded fibroin obtained from transgenic cocoons enabled the formation of fibroin sponges with varying densities by using 1–5% (v/v) alcohol. The effective chondrogenic differentiation of ATDC5 cells was induced following their cultivation on substrates coated with intact fibroin. Our results showed that intact, allergen-free fibroin can be obtained from transgenic cocoons without the need for sericin removal, providing a method to produce fibroin-based materials with high biocompatibility for biomedical uses.     

Vibrational modes of flavin bound to riboflavin binding protein from egg white. Resonance Raman spectra of lumiflavin and 8-substituted riboflavin

The resonance Raman (RR) spectra of 8-halogenated-riboflavin, 8-demethyl-riboflavin(8-H-RF), 8-amino-riboflavin(8-NH2-RF), 8-methoxy-riboflavin(8-OCH3-RF), lumiflavin, and 3-methyl-lumiflavin were observed. The Raman lines with the highest frequency are at 1624, 1620, and 1615 cm-1 for 8-chloro-riboflavin, 8-bromo-riboflavin, and 8-iodo-riboflavin, respectively. This systematic shift confirms that the 1631 cm-1 line of riboflavin is derived from the benzene part of isoalloxazine. Substitution at the 8-position by an amino or methoxy group, which has a large influence on the electronic structure of isoalloxazine, changes the RR spectrum markedly in comparison with that of 8-halogenated riboflavin. The 1583 cm-1 line of riboflavin, which involves the vibrational displacement of N(5) and C(4a) atoms of isoalloxazine, is shifted to the low frequency side by substitution at the 8-position with an amino or methoxy group. The corresponding line of 8-H-RF, on the contrary, shifts to the high frequency side. The RR spectrum of lumiflavin is very different from that of riboflavin in the range from 1200 to 1300 cm-1. Although the pi-electronic structure is little affected by the substitution at the 10-position, the Raman spectrum of lumiflavin in this region is very sensitive.     

Is there a protease that preferentially cleaves the M-line in partially dehydrated muscle?

When a partially dehydrated muscle fibre bundle (PDM, 65% H(2)O, pH 5.5, at 4 °C) was treated with a supernatant fraction (M-line-cleaving fraction: MCF) of muscle homogenate for 5 hr, the M-lines disappeared. MCF was extracted from rabbit skeletal muscles by homogenization with 15 mM HCl containing 0.5 M NaCl (pH 3.7), fractionated with 25-65% (NH(4))(2)SO(4) and clarified by Sephadex G-75. Rabbit psoas PDM was obtained with an osmotic dehydration sheet and glycerinated. One end of the bisected fibre bundle was incubated with 10 mM Na-acetate (pH 5.5), 1 mM EDTA, 5 mM β-mercaptoethanol (β-MCE), 150 mM KCl, 10 mM NaN(3) with MCF at 25 °C for 5 hr, the muscle being stretched and relaxed several times. The other end was incubated in the same solution, except that MCF was omitted (control). Electron microscopy showed the myofibrils broken down at the M-line in the presence of MCF. The myofilaments were closely packed near the Z-line and flared out at both ends near the centre of the sarcomere (bow-tie shape). Thus, the Z-line is not the only target of proteases and structural decomposition can also occur at the M-line under specific conditions. An M-line cleaving protease may exist in the MCF muscle extract.     

Increase in breakdown strength of PE film by additives ofazocompounds

PE films with various additives were prepared by the solution-grown method. The thickness of the films ranged from 5 to 25 μm. Six different azocompounds were used as additives. The results show that BDS 0 for the film with additives was higher than that for the film without additives in the temperature range from -35 to 30°C. The increasing ratio of BDS depended on the composition of the additives used. Our results indicate that the breakdown of the film is induced by an electron avalanche. The conduction current through the film in the high electric field region was reduced by using the additives. The dependence of the conduction current on additives corresponds to that of BDS; a higher BDS is realized for films with additives by which the conductive current is controlled at the lower value. It was considered that the reduction of current by the additive is due to either the trapping effect or the excitation effect of the additive. The trap level for the additive and the excitation energy depend upon the type of radical connected on the benzene ring of the additive: electron-accepting or electron-donating type. The results suggested that high BDS and small current are obtained when the azocompound on which the electron-accepting radical is connected is used as the additive