Ag<Subscript>2</Subscript>O<Subscript>3</Subscript> clathrate is a novel and effective antimicrobial agent

Silver compounds and silver ions are used extensively in medical devices because of their wide-spectrum antimicrobial activity. In particular, nanoparticles of silver and silver (I) oxide show great promise for widespread usage in medical polymers and nanodrugs. Here, we demonstrate that a crystalline powder and a saturated aqueous solution of silver (III) oxide clathrate show much stronger antimicrobial activities and oxidative activities than silver (I) oxide.     

Fabrication and characterization of tetracyanoquinodimethane/phthalocyanine solar cells

Fabrication and characterization of heterojunction solar cells of tetracyanoquinodimethane (TCNQ)/copper phthalocyanine (CuPc) and zinc phthalocyanine (ZnPc) were carried out. The light-induced charge separation with charge transfer was investigated by light-induced current density and optical absorption. In both cases of the TCNQ/CuPc and TCNQ/ZnPc solar cells, the TCNQ thin film worked for strong electron-accepting layer as n-type semiconductor. These behaviors would be originated in charge transfer of excited electron from CuPc and ZnPc to TCNQ. The photovoltaic mechanism was discussed on the basis of the experimental results.     

Titanophosphate glasses as lithium-free nonsilicate pH-responsive glasses—Compatibility between pH responsivity and self-cleaning properties

Lithium silicate-based glasses have been widely used as commercially available pH glass electrodes. It was revealed that Ti³⁺-containing titanophosphate (TiO₂–P₂O₅, TP) glasses are pH-responsive as lithium-free nonsilicate glasses for the first time. The absorption coefficient at 532 nm, α₅₃₂ as a measure of Ti³⁺ content in TP glasses increased with increasing melting temperature. TP glasses with large α₅₃₂ tended to give low electrical resistivity, high pH sensitivity and the short pH response time. The first post-annealing (oxidation of Ti³⁺) of TP glasses at 600–620 °C for 60–240 h resulted in the occurrence of the photo-induced hydrophilicity along with the disappearance of pH responsivity and the increase of electrical resistivity. The second post-annealing (reduction of Ti⁴⁺) of the first post-annealed TP glasses at 600–620 °C for 48 h under vacuum recovered both pH responsivity and electrical resistivity to the level of the as-prepared TP glasses with maintaining the photo-induced hydrophilicity. Moreover, the second post-annealed TP glasses had photocatalytic activity for methylene blue (MB) comparable to commercially available self-cleaning glass. Thus, TP glasses with the compatibility between pH responsivity and self-cleaning properties were obtained by the sequential post-annealing (oxidation and reduction) of as-prepared glasses. From some circumstantial evidences, pH response of TP glasses was explained in terms of phase boundary potential model related to hopping conduction of electron from Ti³⁺ to Ti⁴⁺ via O^2? ion in TP glasses rather than diffusion potential model.     

Experimental prediction of the wavelength-dependent path-length factor for optical intrinsic signal analysis

Analysis of the optical intrinsic signal of an exposed cortex has been applied to measurement of functional brain activation. It is important for accurate measurement of concentration changes in oxygenated hemoglobin and deoxygenated hemoglobin to consider the wavelength dependence of the mean optical path lengths for the reflectance of cortical tissue. A method is proposed to experimentally estimate the wavelength dependence of the mean optical path length in cortical tissue from the multispectral reflectance of the exposed cortex without any additional instruments. The trend in the wavelength dependence of the mean optical path length estimated by the proposed method agrees with that estimated by the model-based prediction, whereas the magnitude of the wavelength dependence predicted by the proposed method is greater than that of the model-based prediction. The experimentally predicted mean optical path length minimizes the difference in the measured changes in the concentrations of the oxygenated hemoglobin and deoxygenated hemoglobin calculated from different wavelength pairs.     

Preferred crystal orientation of sol-gel-derived Bi4-xLaxTi3O12 thin films on silicon substrates

Polycrystalline thin films of La-substituted bismuth titanate (BLT) were formed directly on p-type Si(100) substrates by using sol-gel and spin coat methods. The BLT film and interfacial layer between BLT and Si were quantitatively investigated by the X-ray reflectivity method. Also, crystal orientations of sub-100-nm-thick BLT thin films were confirmed by X-ray diffraction using a synchrotron radiation source. The preferred c-axis orientation normal to the surface depended on the crystallization temperature. The difference in the preferred c-axis orientations of the BLT films caused the difference in the hysteresis voltage width in the capacitance-voltage characteristics of Au/BLT/p-Si structures. Furthermore, the c-axis of the Bilayered structure was preferentially oriented and aligned in the in-plane direction.     

JxB Arc Jet Fullerene Producer with a Revolver Type Automatic Material Injector

In order to produce various kinds of fullerenes efficiently, a J×B arc jet fullerene reactor with a revolver type automatic and continuous material injector has been developed. The J×B force reduces deposition of carbon vapor on a cathode and increases production rate of fullerenes. Effective production of LaC₆₀ and LaC₇₀ is also obtained by this reactor.     

Analytical methods for determining a system configuration acceptable from viewpoints of both short circuit current and voltage stability

Generally, improving voltage stability to power demand increase tends to increase short circuit capacity. In this paper, two methods are proposed in order to obtain appropriate system separation points that minimize short circuit capacity increase and voltage stability decrease. Considering the Q-ϵ network that expresses the relation of voltage and reactive power, voltage sensitivity is equivalent to an element of the system impedance matrix. A fast calculation procedure for the change of the impedance matrix element due to bus connection changes has been proposed. It can be applied to the calculation of both the voltage sensitivities and the short circuit capacity. The results give information on the most appropriate separation points among the designated candidates, taking account of short circuit capacity problems and voltage stability considerations. The second method proposed uses a linear programming technique with variable line impedances and the objective function minimizing the short circuit capacity subject to bus voltage dip constraints. This gives information on the preferable separation points in large and complicated systems. Some practical procedures are also given. © 1998 Scripta Technica, Electr Eng Jpn, 124(3): 30–39, 1998     

Bacterial cellulose IV. Application to processed foods

A new form of cellulose, bacterial cellulose (BC), features smooth texture and high water-holding capacity. These properties function positively in food systems: BC functions as a heat-stable suspending agent as well as a filler to reinforce the body of fragile food hydrogels, improved the quality of pasty foods by reducing their stickiness, could be applied to meat products as a fat substitute and to jam as a noncaloric bulking agent. These results show that BC will be widely applicable to processed foods to improve their quality.     

Enhanced Light‐Harvesting Capability of a Panchromatic Ru(II) Sensitizer Based on π‐Extended Terpyridine with a 4‐Methylstylryl Group for Dye‐Sensitized Solar Cells

A novel Ru π‐expanded terpyridyl sensitizer, referred to as HIS‐2, is prepared based on the molecular design strategy of substitution with a moderately electron‐donating 4‐methylstyryl group onto the terpyridyl ligand. The HIS‐2 dye exhibits a slightly increased metal‐to‐ligand charge transfer (MLCT) absorption at around 600 nm and an intense π–π* absorption in the UV region compared with a black dye. Density functional theory calculations reveal that the lowest unoccupied molecular orbital (LUMO) is distributed over the terpyridine and 4‐methylstyryl moieties, which enhances the light‐harvesting capability and is appropriate for smooth electron injection from the dye to the TiO₂ conduction band. The incident photon‐to‐electricity conversion efficiency spectrum of HIS‐2 exhibits better photoresponse compared with black dye over the whole spectral region as a result of the extended π‐conjugation. A DSC device based on black dye gives a short‐circuit current (J_SC) of 21.28 mA cm^?2, open‐circuit voltage (V_OC) of 0.69 V, and fill factor (FF) of 0.72, in an overall conversion efficiency (η) of 10.5%. In contrast, an HIS‐2 based cell gives a higher J_SC value of 23.07 mA cm^?2 with V_OC of 0.68 V, and FF of 0.71, and owing to the higher J_SC value of HIS‐2, an improved η value of 11.1% is achieved.