Photo‐reductive fading of disperse azo dyes on nylon substrate: thermochemical analyses of reactions of photo‐induced radicals using the semiempirical molecular orbital method†

When the excited triplet states of disperse azo dyes with nitro groups abstract hydrogen to generate hydrazinyl (from azo groups) and nitrosyl hydroxide radicals (from nitro groups), both the radicals as H‐acceptors carry out azo scission, conversion to nitrogen dioxide via disproportionation reactions and self‐decomposition via rearrangement. A kinetic equation was formulated by the sum of these reactions, which describes the initial rates (K_PA) of reductive fading. The K_PA values were controlled by the rate constants of the reactions of hydrazinyl and nitrosyl hydroxide radicals as H‐acceptors, which were estimated by thermochemical analyses of the reactants, intermediates and end products using the semiempirical molecular orbital PM5 method, and by the concentrations of the reactants: H‐acceptors and H‐donors. The K_PA values observed for 12 dyes were explained semi‐quantitatively by multiple routes of reactions depending upon to what extent each radical reaction was thermochemically favoured.     

Cell surface regulators of complement, 5I2 antigen, and CD59, in the rat eye and adnexal tissues

PURPOSE: Cell surface complement regulatory proteins have been identified in high levels in ocular tissues, but no experimental model is available for examining their physiological roles. To develop such a model, the distribution of 5I2 antigen, a protein possessing the functions of the human decay-accelerating factor (DAF [CD55]) and membrane cofactor protein (MCP [CD46]), and rat inhibitory protein (CD59), the homologue of the human membrane inhibitor of reactive lysis (MIRL[CD59]) were characterized in the rat eye and ocular adnexal structures. METHODS: After euthanasia of female Wistar rats, followed by orbital exenteration, eyelids and orbital tissue including the lacrimal gland were separated from the globes and immediately snap-frozen in liquid nitrogen at -70 degrees C. Tissues then were sectioned at -20 degrees C and examined immunohistochemically for 5I2 antigen and rat CD59. RESULTS: Both molecules were found to be present in high levels in multiple sites. Corneal and conjunctival epithelia showed moderate to intense labeling for both regulators. Fibroblasts in the corneal stroma, conjunctiva, and sclera labeled similarly. Corneal endothelial cells showed intense labeling for rat CD59 but not for 5I2 antigen. The iris and ciliary body showed intense labeling for both proteins. The retina showed labeling at multiple levels, with that of rat CD59 being more intense than that of 5I2 antigen. The lacrimal gland labeled for both regulators. Vessels, muscle, and nerves in the orbit labeled intensely for both antigens. In the eyelid, conjunctiva, sebaceous glands, and muscle and nerve tissues labeled moderately to intensely for both molecules, whereas skin epithelium labeled less intensely. CONCLUSIONS: 5I2 antigen and rat CD59 are expressed in high levels and distributed similarly in the rat eye and lacrimal gland to DAF, MCP, and MIRL in the human eye and lacrimal gland. These findings establish the rat ocular surface as a model for studying the role of cell surface complement regulators in this site. This first identification of copious expression of these proteins in eyelid structures, which also participate in protection of the ocular surface, further suggests an important role for surface complement regulatory proteins in this location.     

Structure of effective catalyst layers around bubbles in a fluidized catalyst bed

In a fluidized catalyst bed, the reactant gas transfers from the bubble phase to the emulsion phase and reactions proceed in the emulsion phase. The catalyst particles around the bubbles should contact the gases containing a high concentration of the reactants. Therefore, the effect of the catalysts around the bubbles is very important for estimating the conversion and selectivity in the reactor. In order to study the role of these catalysts, the hydrogenation of carbon dioxide was carried out in a fluidized catalyst bed. Based on the results, the amount of the catalyst that was effective for the reaction was calculated. In addition, the shape of the bubbles ascending in the fluidized catalyst bed was observed using a fast X-ray computer tomography (CT) scanner. The structure of the bubbles in the fluidized catalyst bed was very complicated and the surface area of the bubbles was much greater than the obtained when assuming spherical shaped bubble. By assuming that effective catalysts existed around the bubbles, the thickness of catalyst layer was obtained. Finally, the 3-dimensional images of the catalyst layers around the bubbles were reconstructed.     

Observation of Magnetic Domain Structures of Magnetic Thin Films by the Lorentz Electron Microscopy

Inthisdecade,agreatmanyresearchworksonmulti-layeredmopeticthinfilmshavebeenreport6d,sincethemagneticmulti-layeredfilmsarethemosthopefulnovelmagneticmaterialsforthenextgenerationelectionicdevises,suchasgialmagneto-resiSbocesensorelemeds.hiordertOdevel...     

An extreame disposition method for low-level radioactive wastes using supercritical water (3)

Disposition of low-level radioactive wastes has been performed in supercritical water with RuO₂ as a catalyst without the addition of any oxidizing materials. These wastes arose from nuclear power plants etc., constituting of nonflammable organic materials, such as fire resistant sheeting and rubber gloves. We investigated the distribution behavior of iron and cobalt attached to nonflammable organic materials, in solid, liquid and gas phases during the decomposition of this method. The distributions of these elements under various conditions (initial amounts) were determined by using their radioisotopes as simulated low-level radioactive wastes in order to ease the detection of trace amounts of elements even in solid and gas phases. Iron and cobalt were found only in the solid phase when non-radioactive iron hydroxide was added as a precipitation reagent before the supercritical-water reaction.     

Synthesis of MgO/ZnO hetero-epitaxial whiskers using chemical vapor deposition operated under atmospheric pressure

A chemical-vapor-deposition (CVD) technique operated under atmospheric pressure is available to synthesize metal oxide crystals with various morphologies. This CVD technique provides highly supersaturating conditions that induce morphological instability of growing crystallites. In this study, the metal oxide material with rock salt structure was selected to confirm the possibility of whisker growth of the cubic system crystal. The MgO whiskers grew epitaxially on the single crystalline substrate of (0001) sapphire under appropriate conditions. The MgO whiskers were also formed epitaxially on the top of the ZnO whiskers. The unique whisker with the MgO/ZnO hetero-junction was successfully obtained.     

A matrix form of fibronectin mediates enhanced binding of Streptococcus pyogenes to host tissue

The pathogenic Gram-positive bacterium Streptococcus pyogenes (group A streptococcus) binds to fibronectin via protein F. In this study, we have investigated the binding properties of protein F to various multimeric tissue forms of fibronectin that appear on cell surfaces and in the extracellular matrix. We show that binding of S. pyogenes through protein F is more efficient to an in vitro-derived polymerized form of fibronectin (superfibronectin) than to soluble fibronectin immobilized in a solid phase. In addition, Chinese hamster ovary cells overexpressing the alpha5beta1 integrin produced an increased amount of a fibronectin matrix and consequently bound a higher number of S. pyogenes cells. Inhibition and direct binding assays using purified proteins demonstrated that binding to a fibronectin matrix involved both domains of protein F (UR and RD2) that have previously been implicated in interactions with fibronectin. Using intact S. pyogenes bacteria in which various domains of protein F were expressed as hybrids with the surface-exposed region of an unrelated protein, we revealed that, in contrast to the predominantly UR-mediated binding to soluble fibronectin, the maximal binding to the fibronectin matrix required RD2 in addition to UR. Since in some infections S. pyogenes may initially encounter a matrix form of fibronectin, these results suggest that UR and RD2 may be important for the initiation of streptococcal infectious processes.     

Au-Fe-Ni permanent magnet alloys

A gold permanent magnet for an ornamental material is developed in the Au-Fe-Ni system. It is found that the magnetic properties of the An-12.5 wt% Fe-12.5 wt% Ni alloy aged at 450°C for seven hours and cold-swaged by 92 percent are Br = 0.53 T (5300 G), iHc = 40.8 kA/m (510 Oe), and (BH)max = 9.1 kJ/m³(1.1 MGOe). The Au-12.5 wt% Fe-10 wt% Ni-2.5 wt% Co alloy aged at 450°C for 2.5 h and swaged by 86 percent attained Br = 0.54 T (5400 G), iHc = 42.4 kA/m (530 Oe), and (BH)max = 9.6 kJ/m3(1.2 MGOe). In these alloys, the magnetic hardening is due to the fine Fe-Ni rich ferromagnetic particles precipitated in the Au matrix.     

Knowledge representation and compilation for symptom-disease-testrelationships

A method that represents and compiles expert knowledge for choosing diagnostic tests is presented. Usually, physicians inquire into the patient's complaints, examine him/her physically, and on the assumption of a specific disease or impaired organ system, choose a certain group of laboratory tests designed to examine this assumption. After checking the test results, they may perform another set of tests for further differential diagnosis. This step is repeated until they obtain the final diagnosis. In the proposed method, this knowledge is categorized into three relations. The relation SD is defined on domains symptom/sign and disease, the relation DT is on disease and diagnostic test, and the relation DD is on disease and disease where the first attribute (column) in each relation, respectively, is a primary key, that is, there exists precisely one value, and the second is a set of values. We show that redundant tuples can be reduced or decomposed by checking whether or not there exist tuples whose set of diagnostic tests are equivalent to that of other tuples or are a subset of others. Finally, we can obtain a preferable set of diagnostic tests for given symptoms/signs by using the join of SD and DT, and for further diagnosis, the join of DD and DT is applicable.