Structural analysis of coating film with ultra-small-angle x-ray scattering

The structure of magnetic coating films was analyzed by the ultra-small-angle X-ray scattering (USAXS) technique. Small-angle X-ray scattering (SAXS) has been used to investigate the size, shape, and correlation of the nm sized structure. USAXS, with a measurable range extending to the μm order, can be used to analyze the submicron sized structure of paints and coating films. Preliminary USAXS experiments for a magnetic paint and magnetic coating films revealed that USAXS is useful to evaluate the structure of the particles in the paint and the films. Combined with other experimental methods, USAXS will provide a new kind of information about the structural analysis. Yokohama Research Center, 1000 Kamoshida, Aoba-ku, Yokohama, 227-8502, Japan. Department of Polymer Chemistry, Kyoto, 606-8501, Japan.     

Simple low-vacuum coating of paraffin wax on carbonaceous gas sensing layers

A simple low-vacuum coater has been fabricated by using a vacuum resin degassing chamber, in which an aluminum effusion cell is heated by a soldering iron. Our developed vacuum coater presents the versatile methods for depositing paraffin wax for skin-coating the sensing layers of quartz crystal microbalance (QCM). As the increase of the cell temperature, the thickness and inhomogeneity of the wax films were increased. Impedance analyses revealed that the energy dissipation of the QCM was remarkably enhanced with the amount of wax. It was also revealed that the as-deposited wax was fluidic until coagulation by heat radiation. This surface skin coating enhanced the ethyl acetate (EA) sorption capabilities of the polyethylene-sputtered QCM sensor, whereas, it reduced the EA sorption capacity of the d-phenylalanine-sputtered QCM sensor.     

Association of atherosclerosis and cardiac cell dysfunction

It is recognized that heart failure in patients with atherosclerotic lesion is the result of ischemia. However, there may also be cardiac cell dysfunction independent of ischemia, as factors advancing both of atherosclerosis and heart failure are discovered. The renin-angiotensin system is one of factor and angiotensin-converting enzyme inhibitor (ACEi) prevents progression of atherosclerotic lesion and heart failure. To elucidate the association of atherosclerosis and cardiac cell dysfunction, we investigated the effects of ACEi on cultured cardiac myocytes. Captopril increased beta-receptor density of myocytes and augmented the response to isoproterenol. CV-3480, a ACEi, also up-regulated beta-receptors but angiotensin I, angiotensin II and angiotensin type I receptor antagonist did not. Bradykinin B2 receptor blocker, HOE140, suppressed the effect of captopril on cultured cells. The results suggest that ACEi up-regulated beta-receptors and augmented the response to beta-receptor agonist through BK potentiation.     

Preparation of flame-retardant polyethylene foam of open-cell type by radiation grafting of vinyl phosphonate oligomer

Flame-retardant polyethylene foam was successfully obtained by grafting a vinyl phosphonate oligomer onto polyethylene foam of an open-cell type using a simultaneous radiation grafting technique. The foam was impregnated with the oligomer and irradiated in a nitrogen atmosphere with an electron beam. The grafted foam thus obtained was found to pass the three most severe flammability tests that have to be cleared when the foam is to be used for materials where high flame-retardant property is required. No hydrogen cyanide was detected in burning exhaust gas of the grafted foam. © 1994 John Wiley & Sons, Inc.     

Portal-hypertensive gastropathy develops less in patients with cirrhosis and fundal varices

BACKGROUND/AIMS: The aim of this prospective study was to examine the association of portal-hypertensive gastropathy and fundal varices in patients with cirrhosis. METHODS: We carried out an endoscopic observation in 476 patients with cirrhosis (study 1), including 62 patients undergoing endoscopic obliteration of esophageal varices (study 2). In study 1, patients were classified into five subgroups: no esophagofundal varices (n=119), small esophagofundal varices (n=127), dominant esophageal varices (n=177), dominant fundal varices (n=27), and large esophagofundal varices (n=26). The severity of liver dysfunction was assessed by Pugh-Child classification: class A (n=222), class B (n=200), and class C (n=54). In study 2, two groups, poorly developed fundal varices (n=50) and well developed fundal (n=12), were distinguished and the follow-up endoscopic examinations were performed on the basis of 3-month intervals for 2 years. In each study, the severity of portal-hypertensive gastropathy was scored: 0 (absent), 1 (mild), 2 (severe), and 3 (bleeding). RESULTS: Study 1: One-way ANOVA showed that both variceal pattern and Pugh-Child class significantly influenced portal-hypertensive gastropathy score. However, two-way ANOVA indicated that variceal pattern was the only significant variable. Portal-hypertensive gastropathy score was significantly higher in patients with dominant esophageal varices than in either patients with no esophagofundal varices or patients with small esophagofundal varices. In contrast, portal-hypertensive gastropathy score in patients with dominant fundal varices was similar to that in patients with no esophagofundal varices and was significantly lower compared with that in patients with dominant esophageal varices. Furthermore, portal-hypertensive gastropathy score was significantly lower in patients with large esophagofundal varices than in patients with dominant esophageal varices. Study 2: After the obliteration of esophageal varices, portal-hypertensive gastropathy score in patients with poorly developed fundal varices became significantly higher at 3-, 6-, 9-months while it was not modified in patients with well developed fundal varices during the follow-up period. Furthermore, the integrated incremental change in portal-hypertensive gastropathy score during the first 1-year follow-up period was significantly lower in patients with well developed fundal varices than in patients with poorly developed fundal varices. CONCLUSIONS: These results indicate that both spontaneous and obliteration-induced portal-hypertensive gastropathy lesions develop less in patients with cirrhosis and fundal varices.     

Preparation of hydrophilic polyethylene foam of open cell type by radiation grafting of acrylic acid

Hydrophilic polyethylene foam was synthesized by radiation grafting of acrylic acid onto polyethylene foam of open cell type using monomer solution containing Mohr's salt which inhibits homopolymerization of the monomer. The graft foam was easily dyed by cationic dyes and showed excellent moisture regain. The wicking properties were also excellent and were almost the same as those of commercially available PVA foam. The surface resistivity of 10¹⁶ ohm of the original foam decreased to 10⁶ ohm and half decay time of surface charge decreased from 8000 s to 1 s by the grafting, indicating that the grafted foam has excellent antistatic properties.     

The discrete-time quaternionic quantum walk on a graph

Recently, the quaternionic quantum walk was formulated by the first author as a generalization of discrete-time quantum walks. We deal with the right eigenvalue problem of quaternionic matrices in order to study spectra of the transition matrix of a quaternionic quantum walk. The way to obtain all the right eigenvalues of a quaternionic matrix is given. From the unitary condition on the transition matrix of a quaternionic quantum walk, we deduce some remarkable properties of it. Our main results determine all the right eigenvalues of the quaternionic quantum walk by using those of the corresponding weighted matrix. In addition, we give some examples of quaternionic quantum walks and their right eigenvalues.     

Photo-induced super-hydrophilic property and photocatalysis on transparent Ti-containing mesoporous silica thin films

The transparent Ti-containing mesoporous silica thin films can be prepared on quartz plate using a spin-coating sol–gel method. The spectroscopic characterization has revealed that the Ti-containing mesoporous silica thin films contain isolated and tetrahedrally-coordinated titanium oxide moieties in the frameworks. Compared with the common mesoporous silica thin films, these Ti-containing mesoporous silica thin films have demonstrated a strong hydrophilic surface property even before UV-irradiation. After UV-light irradiation, the contact angle of water droplet on the Ti-containing mesoporous silica thin films became lower, indicating the appearance of the super-hydrophilic property. Under UV-light irradiation Ti-containing mesoporous silica thin films also exhibited highly selective activity for the photocatalytic oxidation of propylene. The isolated and tetrahedrally-coordinated titanium oxide moieties are responsible for these photo-induced surface reactions.