Upper Critical Field of Organic Superconductor κ-(ET)2Cu(NCS)2 Determined by Specific Heat Measurements

Both specific heat and resistance measurements of organic superconductor -(ET)₂Cu(NCS)₂ under magnetic field were performed. Upper critical fields, obtained from the specific heat data, are significantly less than those from the magnetoresistance measurements. At temperatures below 2 K and magnetic fields below 1 T, we observed additional power dissipation due to the field sweep. This effect may be attributed to the existence of irreversibility line.     

Oxidation Reaction between Periodate and Polyhydroxyl Compounds and Its Application to Chemiluminescence

The oxidation reaction between periodate and polyhydroxyl compounds was studied. A strong chemiluminescent (CL) emission was observed when the reaction took place in a strong alkaline solution without any special CL reagent. However, in acidic or neutral solution, it was hard to record the CL with our instrument. It was interesting to find that in the presence of carbonate the CL signal was enhanced significantly. When O(2) gas and N(2) gas were blown into the reagent solutions, both background and CL signals of the sample were enhanced by O(2) and decreased by N(2). The spectral distribution of the CL emission showed two main bands (λ = 436-446 and 471-478 nm). Based on the studies of the spectra of CL, fluorescence and UV-visible, a possible CL mechanism was proposed. In strongly alkaline solution, periodate reacts with the dissolved oxygen to produce superoxide radical ions. A microamount of singlet oxygen ((1)O(2)*) could be produced from the superoxide radicals. A part of the superoxide radicals acts on carbonates and/or bicarbonates leading to the generation of carbonate radicals. Recombination of carbonate radicals may generate excited triplet dimers of two CO(2) molecules ((CO(2))(2)*). Mixing of periodate with carbonate generated were very few (1)O(2)* and (CO(2))(2)*. These two emitters contribute to the CL background. The addition of polyhydroxyl compounds or H(2)O(2) caused enhancement of the CL signal. It may be due to the production of (1)O(2)* during the oxidized decomposition of the analytes in periodate solution. This reaction system has been established as a flow injection analysis for H(2)O(2), pyrogallol, and α-thioglycerol and their detection limits were 5 × 10(-)(9), 5 × 10(-)(9), and 1 × 10(-)(8) M, respectively. Considering the effective reaction ions, IO(4)(-), CO(3)(2)(-), and OH(-) could be immobilized on a strongly basic anion-exchange resin. A highly sensitive flow CL sensor for H(2)O(2), pyrogallol, and α-thioglycerol was also prepared.     

Deposition at low substrate temperatures of high-quality TiO2 films by radical beam-assisted evaporation

We deposited high-quality TiO(2) films by an oxygen-radical beam-assisted evaporation (RBE) method at a lower substrate temperature (Ts) than that for a TiO(2) film deposited by conventional thermal evaporation (TE) with neutral-oxygen gas. The films were then evaluated in terms of refractive index, shift of wavelength of a peak in the reflection curve, and absorption coefficient. The TiO(2) films deposited by RBE at Ts < 473 K showed higher refractive indices, were more compact, and had lower absorption coefficients than the film deposited by TE at Ts = 473 K.     

Bottom-up synthesis of carbon materials with high pyridinic-nitrogen content from dibenzacridine isomers with zigzag and armchair edges

Journal of Materials Science - Nitrogen-doped carbon materials, especially pyridinic nitrogen, have attracted attention because of the high performance for various applications such as electrodes...     

Thermal stabilization of penicillolysin, a thermolabile 19 kDa Zn2+-protease, obtained by site-directed mutagenesis

Penicillolysin is a member of the clan MX and the family of M35 proteases. The enzyme is a thermolabile Zn(2+)- protease from Penicillium citrinum with a unique substrate profile. We expressed recombinant penicillolysin in Aspergillus oryzae and generated several site-directed mutants, R33E/E60R, A167E and T81P, with the intention of exploring thermal stabilization of this protein. We based our choice of mutations on the structures of homologous thermally stable enzymes, deuterolysin (EC 3.4.24.39) from A.oryzae and a peptidyl-Lys metallopeptidase (GfMEP) from the edible mushroom Grifora frondsa. The resulting mutant proteins exhibited comparable catalytic efficiency to the wild-type enzyme and some showed a higher tolerance to temperature.     

An Aspect-Oriented Approach to Modular Behavioral Specification

Behavioral interface specification languages, such as Java Modeling Language (JML), can be used to specify the behavior of program modules. We have developed a behavioral interface specification language Moxa, an extension of JML. Moxa provides a new modularization mechanism called assertion aspect that can capture the crosscutting properties among assertions. In this paper, we briefly explain the notion of assertion aspects and the design of Moxa, and then we show an example specification. By comparing the specification to its JML counterpart, we show that the use of assertion aspects clarifies the large, complex specification and greatly simplifies each assertion in the specification.     

Cold-active pectinolytic activity of psychrophilic-basidiomycetous yeast Cystofilobasidium capitatum strain PPY-1

A pectinolytic and psychrophilic yeast was isolated from soil from Abashiri, Hokkaido, Japan. The phenotype and sequencing of the 28S rDNA of the isolated strain (PPY-1) indicated a taxonomic affiliation to the basidiomycetous yeast Cystofilobasidium capitatum. C. capitatum strain PPY-1 was able to grow on two pectic compounds, polygalacturonate and pectin, at below 5 degrees C. Moreover, the extracellular fraction of the strain exhibited pectin methylesterase, pectin lyase and polygalacturonase activities at 5 degrees C. Thus strain PPY-1 may produce novel enzymes that are able to degrade pectin at low temperature, although the strain has isozymes of these enzymes.     

Improvement of image quality in diffuse optical tomography by use of full time-resolved data

In the field of diffuse optical tomography (DOT), it is widely accepted that time-resolved (TR) measurement can provide the richest information on photon migration in a turbid medium, such as biological tissue. However, the currently available image reconstruction algorithms for TR DOT are based mostly on the cw component or some featured data types of original temporal profiles, which are related to the solution of a time-independent diffusion equation. Although this methodology can greatly simplify the reconstruction process, it suffers from low spatial resolution and poor quantitativeness owing to the limitation of effectively applicable data types. To improve image quality, it has been argued that exploiting the full TR data is essential. We propose implementation of a DOT algorithm by using full TR data and furthermore a variant algorithm with time slices of TR data to alleviate the computational complexity and enhance noise robustness. Compared with those algorithms where the featured data types are used, our evaluations on the spatial resolution and quantitativeness show that a significant improvement in imaging quality can be achieved when full TR data are used, which convinces the DOT community of the potential advantage of the TR domain over cw and frequency domains.     

Directed Vertical Diffusion of Photovoltaic Active Layer Components into Porous ZnO‐Based Cathode Buffer Layers

Cathode buffer layers (CBLs) can effectively further the efficiency of polymer solar cells (PSCs), after optimization of the active layer. Hidden between the active layer and cathode of the inverted PSC device configuration is the critical yet often unattended vertical diffusion of the active layer components across CBL. Here, a novel methodology of contrast variation with neutron and anomalous X‐ray reflectivity to map the multicomponent depth compositions of inverted PSCs, covering from the active layer surface down to the bottom of the ZnO‐based CBL, is developed. Uniquely revealed for a high‐performance model PSC are the often overlooked porosity distributions of the ZnO‐based CBL and the differential diffusions of the polymer PTB7‐Th and fullerene derivative PC₇₁BM of the active layer into the CBL. Interface modification of the ZnO‐based CBL with fullerene derivative PCBE? OH for size‐selective nanochannels can selectively improve the diffusion of PC₇₁BM more than that of the polymer. The deeper penetration of PC₇₁BM establishes a gradient distribution of fullerene derivatives over the ZnO/PCBE‐OH CBL, resulting in markedly improved electron mobility and device efficiency of the inverted PSC. The result suggests a new CBL design concept of progressive matching of the conduction bands.     

Field validation of the ASTER Temperature-Emissivity Separation algorithm

The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) has operated since 19 December 1999 from NASA's Terra Earth-orbiting, sun-synchronous satellite. The Temperature-Emissivity Separation (TES) algorithm is used to calculate surface temperature and emissivity standard products, predicted to be within +1.5 K and +0.015 of correct values, respectively. Analyses of time sequences of ASTER images showing validation sites at Lake Tahoe, California, the Salton Sea, California, Railroad Valley Nevada, and the island of Hawai?i demonstrate that TES generally performs within these limits. The validation experiments also demonstrate that, under unusual atmospheric conditions of anomalously high humidity or spatial variability, atmospheric compensation can be incomplete and errors in temperature and emissivity images can be larger than anticipated.