Structural properties of trypsin from cold-adapted fish,arabesque greenling (<Emphasis Type="Italic">Pleurogrammus azonus</Emphasis>)

A cDNA clone encoding trypsin (AG-T) was isolated from the pyloric ceca of cold-adapted fish, arabesque greenling (Pleurogrammus azonus). The cDNA was composed of 892 bp with an open reading frame of 729 bp at nucleotide positions 25–753. Similar to all the known trypsin, the AG-T seemed to be synthesized as preproenzyme that contains a hydrophobic signal peptide, an activation pentapeptide and a mature trypsin of 222 amino acid residues. The AG-T also completely conserved the major structural features common to trypsin such as the catalytic triad (His57, Asp102, and Ser195), the obligatory Asp189 and twelve Cys residues. On the other hand, the AG-T possessed the deletion of Tyr151 and substitution of Pro152 for Gly in the autolysis loop when aligned with the sequence of tropical-zone fish and bovine trypsins. In addition, Val75 concerned in a combination with calcium ion was exchanged for Ala in the AG-T, and the content of positively charged amino acid residues at the calcium-binding site of the AG-T was three times higher than those of tropical-zone fish trypsins. Moreover, the ratio between charged and hydrophobic amino acid residues in the N-terminal region of the AG-T was also higher than those of temperate-zone fish and tropical-zone fish trypsins. Such structural properties of the AG-T would contribute to its low thermostability.     

Internal voltage generator for low voltage, quarter-micrometerflash memories

A fabricated bandgap generator using 0.25-μm Flash memory process generated a stable reference voltage under 4 V, boosted from an external power supply of 2.5 V. The generated voltage was 1.297±0.025 V at a power supply of 4 V±10%; the temperature dependence was +0.7 mV/°C. The characteristics of a triple-well bipolar transistor for the Flash memory process are sufficient for a reference voltage generator; f_T is 230 MHz, and H_FE is 70. Dynamic operation reduced the average current consumption from 306 to 8.6 μA. Fabricated voltage-doubler circuits generated a voltage 1.8 times larger than that from conventional charge-pump circuits     

The prevalence of Toxoplasma antibody in patients with various ocular diseases in central Japan

BACKGROUND: Ocular toxoplasmosis has been considered to be a largely asymptomatic infection because of the high seroprevalence of Toxoplasma antibodies and the low rate of clinical diagnosis. On the other hand, Toxoplasma infection has been reported to be associated with the other ocular disease. To investigate the association of Toxoplasma infection with the development of various ocular diseases, we studied Toxoplasma seroprevalence in patients with various ocular diseases. METHODS: We investigated Toxoplasma seroprevalence in 982 patients with various ocular diseases in central Japan. Then we compared the seroprevalence of anti-Toxoplasma antibodies. RESULTS: Of 982 patients with various ocular diseases, 122 (12.4%) had serological evidence of previous exposure to Toxoplasma gondii. There were no statistically significant differences among the patients with various ocular diseases. However, the seroprevalence in patients aged 40 to 99 years with macular degenerative lesions was significantly higher than that in patients without these lesions (P < 0.05, Yates' correction). CONCLUSION: This result suggests that Toxoplasma infection could play some role in the development of a type of macular degenerative lesion.     

Comprehensive approach to intrinsic charge carrier mobility in conjugated organic molecules, macromolecules, and supramolecular architectures

Si-based inorganic electronics have long dominated the semiconductor industry. However, in recent years conjugated polymers have attracted increasing attention because such systems are flexible and offer the potential for low-cost, large-area production via roll-to-roll processing. The state-of-the-art organic conjugated molecular crystals can exhibit charge carrier mobilities (μ) that nearly match or even exceed that of amorphous silicon (1-10 cm(2) V(-1) s(-1)). The mean free path of the charge carriers estimated from these mobilities corresponds to the typical intersite (intermolecular) hopping distances in conjugated organic materials, which strongly suggests that the conduction model for the electronic band structure only applies to μ > 1 cm(2) V(-1) s(-1) for the translational motion of the charge carriers. However, to analyze the transport mechanism in organic electronics, researchers conventionally use a disorder formalism, where μ is usually less than 1 cm(2) V(-1) s(-1) and dominated by impurities, disorders, or defects that disturb the long-range translational motion. In this Account, we discuss the relationship between the alternating-current and direct-current mobilities of charge carriers, using time-resolved microwave conductivity (TRMC) and other techniques including field-effect transistor, time-of-flight, and space-charge limited current. TRMC measures the nanometer-scale mobility of charge carriers under an oscillating microwave electric field with no contact between the semiconductors and the metals. This separation allows us to evaluate the intrinsic charge carrier mobility with minimal trapping effects. We review a wide variety of organic electronics in terms of their charge carrier mobilities, and we describe recent studies of macromolecules, molecular crystals, and supramolecular architecture. For example, a rigid poly(phenylene-co-ethynylene) included in permethylated cyclodextrin shows a high intramolecular hole mobility of 0.5 cm(2) V(-1) s(-1), based on a combination of flash-photolysis TRMC and transient absorption spectroscopy (TAS) measurements. Single-crystal rubrene showed an ambipolarity with anisotropic charge carrier transport along each crystal axis on the nanometer scale. Finally, we describe the charge carrier mobility of a self-assembled nanotube consisting of a large π-plane of hexabenzocoronene (HBC) partially appended with an electron acceptor. The local (intratubular) charge carrier mobility reached 3 cm(2) V(-1) s(-1) for the nanotubes that possessed well-ordered π-stacking, but it dropped to 0.7 cm(2) V(-1) s(-1) in regions that contained greater amounts of the electron acceptor because those molecules reduced the structural integrity of π-stacked HBC arrays. Interestingly, the long-range (intertubular) charge carrier mobility was on the order of 10(-4) cm(2) V(-1) s(-1) and monotonically decreased when the acceptor content was increased. These results suggest the importance of investigating charge carrier mobilities by frequency-dependent charge carrier motion for the development of more efficient organic electronic devices.     

Assembly study for JT-60SA tokamak

The assembly scenarios and assembly tools of the major tokamak components for JT-60SA are studied in the following. (1) The assembly frame (with a dedicated 30-tonne crane), which is located around the JT-60SA tokamak, is adopted for effective assembly works in the torus hall and the temporary support of the components during assembly. (2) Metrology for precise positioning of the components is also studied by defining the metrology points on the components. (3) The sector segmentation for weld joints and positioning of the vacuum vessel (VV), the assembly scenario and tools for VV thermal shield (TS), the connection of the outer intercoil structure (OIS) and the installation of the final toroidal field coil (TFC) are studied, as typical examples of the assembly scenarios and tools for JT-60SA.     

Fabrication of novel composites of ZnO-nanoparticles and magadiite

Novel composites of ZnO-nanoparticles and magadiite were successfully prepared by a simple ion-exchange technique in an aqueous suspension of magadiite (Na₂Si₁₄O₂₉·nH₂O) and Zn(NO₃)₂. The TEM and STEM measurements showed that the composites have a structure in which ZnO-nanoparticles with relatively uniform particle sizes are well dispersed within the interlaminar spaces of the magadiite matrix. The particle sizes of the ZnO-nanoparticles were found to depend on the heat-treatment temperature; the average particle sizes are ~ 2.6, ~ 2.8, ~ 4.4 and ~ 4.6 nm, respectively, for the temperatures of 40, 180, 300 and 600 °C. It was also found that the ZnO nanoparticles crystallize and form a single-crystalline particle when the temperature exceeds ~ 300 °C.     

Effects of Ultrafine Single-Nanometer Oxygen Bubbles on Radiation Sensitivity in a Tumor-Bearing Mouse Model

Radiation therapy against cancer cells often causes radiation resistance via accumulation of hypoxia-inducible factor 1 subunit alpha (HIF-1α) under hypoxic conditions and severe side effects. Radiation sensitizers without side effects are required to overcome hypoxia-induced radiation resistance and decrease radiation-related side effects in patients with refractory cancer. We previously developed oxygen nanobubble water (NBO₂ water) and demonstrated that it suppresses hypoxia-induced radiation resistance in cancer cell lines within the single-nanometer range. This study aimed to elucidate whether NBO₂ water could act as a radiosensitizer via regulation of HIF-1α in a tumor-bearing mouse model. Six-week-old female BALB/c mice subcutaneously injected with tumor cells received control water or NBO₂ water for 28 days, after which biochemical examinations and radiation treatment were performed. Hypoxic tumor regions were detected immunohistochemically. We found that NBO₂ water sensitized radiation reactivity in the xenografted tumors. Notably, NBO₂ water administration downregulated the accumulation of HIF-1α in xenografted tumors and did not affect the vital organs of healthy mice. The combination of radiation and single-nanometer NBO₂ water without severe side effects may be a promising therapeutic option to improve radiation sensitivity in cancer patients without tolerance to invasive treatments.