Influence of Gamma Irradiation and Water Aging on the Space Charge Characteristics of Epoxy Micro-Nano Composites.

Epoxy micro-nano composites are well-known to exhibit enhanced electrical, mechanical as well as thermal properties compared to base epoxy resin. Yet, a clear understanding need to be achieved on the long-term aging performance of the epoxy micro-nano composites. The present review article is a comprehensive study on the impact of gamma irradiation and water aging on the space charge characteristics of epoxy micro-nano composites that are applicable as insulant in high-voltage power apparatus. Ion-trapping nanoparticles, which possess good oxidation resistance and high ion trapping ability, are being chosen as nanofillers along with silica micro fillers in epoxy micro-nano composite material for improving the reliability of electrical insulation structures. The epoxy micro-nano composite specimens were subjected to gamma irradiation (4 kGy and 8 kGy) and water aging (under room temperature and at 90 °C), to analyze the effect of aging on space charge accumulation and charge decay characteristics. The mean magnitude of accumulated space charge density of epoxy micro-nano composites tends to increase with an increase in gamma irradiation dose as well as an increment in water diffusion coefficient. The mean lifetime of the space charge decay during depoling has significantly reduced after gamma irradiation and is converse with water aged specimen. Voltage polarity reversal studies have indicated that a part of homo-charge injected from electrodes remained as hetero-charge just after polarity reversal and could result in the distortion of electric field thereby increasing the electric field enhancement factor.

Adsorption characteristics of an enteric virus-binding protein to norovirus, rotavirus and poliovirus.

BACKGROUND: Water contamination with human enteric viruses has posed human health risks all over the world. Reasonable and facile methodologies for recovering and quantifying infectious enteric viruses in environmental samples are needed to address the issues of waterborne viral infectious diseases. In this study, a bacterial protein that has a binding capability with several enteric viruses is discovered, and its binding characteristics were investigated for utilizing it as a viral adsorbent in virus recovery and detection technologies. RESULTS: A gene of an enteric virus-binding protein (EVBP), derived from a monomer of a bacterial chaperon protein GroEL, was successfully acquired from a genomic DNA library of activated sludge microorganisms with nested PCR. Equilibrium dissociation constants between EVBP and norovirus-like particles (NoVLPs) of genotypes GI.7 and GII.4, estimated with quartz crystal microbalance method, were 240 and 210 nM, respectively. These values of equilibrium dissociation constant imply that the binding affinity between EVBP and NoVLPs is 1 to 3-log weaker than that in general antigen-antibody interactions, but about 2-log stronger than that in weak specific interactions of proteins with cations and organic polymers. The adsorptions of EVBP to norovirus, group A rotavirus and poliovirus type 1 were found to be significant in enzyme-linked immunosorbent assay. Meanwhile, the binding of native GroEL tetradecamer to viral particles was weaker than that of EVBP, presumably because of a steric hindrance. The small molecule of EVBP could have an advantage in the access to the surface of viral particles with rugged structure. CONCLUSIONS: EVBP that has a broad binding spectrum to enteric viruses was newly discovered. The broad binding characteristic of EVBP would allow us to utilize it as a novel adsorbent for detecting diverse enteric viruses in clinical and environmental samples.

Human sapovirus in clams, Japan.

Human sapovirus was detected in 4 of 57 clam packages by reverse transcription-PCR and sequence analysis. This represents the first finding of sapovirus contamination in food. Closely matching sequences have been detected in stool specimens from patients with gastroenteritis in Japan, which indicates a possible food-to-human transmission link.

Sapovirus in water, Japan.

Sapoviruses are etiologic agents of human gastroenteritis. We detected sapovirus in untreated wastewater, treated wastewater, and a river in Japan. A total of 7 of 69 water samples were positive by reverse transcription-PCR. Phylogenetic analysis of the viral capsid gene grouped these strains into 4 genetic clusters.

Ab initio MO analysis of interaction paths between radicals in ferromagnetic organic systems.

Interaction path analyses for pi-conjugated organic systems were performed at the ab initio molecular orbital level to examine the relationship between inter-radical interactions and the high-spin stability of the system. It was found that the high-spin stability results from through-bond interactions between radicals, not from through-space interactions, in relation to the stabilization of a low-spin state due to the effects of electron correlation. L(ij)(min) value for estimating the mixing of nonbonding molecular orbitals well predicted the relationship between the through-bond interactions and the high-spin stability. Furthermore, molecular orbital calculations revealed that the all-trans type interaction path between radicals produces long-range exchange interactions, and the additivity of high-spin stability is observed by keeping short-range through-bond interaction paths.

Combined cox maze procedure, septal myectomy, and mitral valve replacement for severe hypertrophic obstructive cardiomyopathy complicated by chronic atrial fibrillation.

Atrial fibrillation (AF) has been reported to be an important prognostic indicator for clinical deterioration particularly in patients with hypertrophic obstructive cardiomyopathy (HOCM). A 66-year-old female complained of severe exertional dyspnea and tachycardia, which were resistant to medical treatments. Doppler echocardiography demonstrated a peak left ventricular outflow tract (LVOT) gradient of 117 mmHg at rest. A catheter examination revealed left ventricular end diastolic pressure of 34 mmHg, a cardiac index of 1.94 L/minute/m(2), and a peak LVOT gradient of 70 mmHg at rest. A transaortic septal myotomy/myectomy was performed first, and Cox maze III procedure was performed through the right and left atrium followed by mitral valve replacement. The patient recovered dramatically except for temporary complete atrioventricular block. One year after operation, the patient is doing well with sinus rhythm and the echocardiogram revealed a peak LVOT pressure gradient of 7.6 mmHg at rest. This surgical approach might be recommended for the treatment of AF in HOCM. (Ann Thorac Cardiovasc Surg 2003; 9: 323-5)

Stripping operation with sclerotherapy for primary varicose veins due to greater saphenous vein reflux: three-year results.

The purpose of this study was to compare the recurrence-free rates of stripping with varicectomy and stripping with sclerotherapy for the treatment of primary varicose veins due to greater saphenous vein insufficiency. This is a multicenter retrospective analysis of 186 patients and 220 limbs treated for primary varicose veins due to greater saphenous vein reflux from January 1996 to December 1997. The difference between the two groups was evaluated by the Chi(2) test or t-test. The recurrence-free rates were estimated by the Kaplan-Meier life-table method. The mean follow-up period was 3.2 +/- 1.1 years. The clinical backgrounds of patients with varicectomy stripping and sclerotherapy stripping were not significantly different between the two groups. The overall recurrence-free rates at 1 and 3 years were 97.0% and 91.4%, respectively. The recurrence-free rates at 3 years were 93.5% for stripping with varicectomy and 88.6% for stripping with sclerotherapy. No statistical difference was found between the two groups. The recurrence rate after stripping with sclerotherapy was equivalent to that after stripping with varicectomy. Thus concurrent varicectomy can be replaced with sclerotherapy.

Venous stasis ulcers due to primary, isolated deep venous insufficiency in a patient with systemic lupus erythematosus: report of a case.

Primary, isolated deep venous incompetence is rare, difficult to diagnose, and can lead to the development of venous stasis ulcers. We herein report a case demonstrating chronic venous stasis ulcers due to primary, isolated deep venous incompetence, which was misdiagnosed as vasculitis ulcers associated with systemic lupus erythematosus (SLE). Although primary, isolated deep venous incompetence is rare, it is important to bear this possibility in mind when a patient presents with leg ulcers.

Complete inhibition of tobamovirus multiplication by simultaneous mutations in two homologous host genes.

The TOM1 gene of Arabidopsis thaliana encodes a putative multipass transmembrane protein which is necessary for the efficient multiplication of tobamoviruses. We have previously shown that mutations severely destructive to the TOM1 gene reduce tobamovirus multiplication to low levels but do not impair it completely. In this report, we subjected one of the tom1 mutants (tom1-1) to another round of mutagenesis and isolated a new mutant which did not permit a detectable level of tobamovirus multiplication. In addition to tom1-1, this mutant carried a mutation referred to as tom3-1. Positional cloning showed that TOM3 was one of two TOM1-like genes in Arabidopsis. Based on the similarity between the amino acid sequences of TOM1 and TOM3, together with the results of a Sos recruitment assay suggesting that both TOM1 and TOM3 bind tobamovirus-encoded replication proteins, we propose that TOM1 and TOM3 play parallel and essential roles in the replication of tobamoviruses.

Catalysis of the Electroreduction of O(2) to H(2)O by Vanadium-salen Complexes in Acidified Dichloromethane.

Addition of stoichiometric quantities of trifluoromethanesulfonic (triflic) acid to solutions of V(IV)O(salen) (H(2)salen = N,N '-ethylenebis(salicylideneamine)) in dichloromethane produces the &mgr;-oxo dinuclear vanadium(IV) complex [(salen)V(IV)OV(IV)(salen)](2+) ([V(IV)OV(IV)](2+)). Addition of significant excesses of triflic acid converts the dimer into [V(IV)(salen)](2+). In dichloromethane solutions containing 0.1 M tetrabutylammonium tetrafluoroborate, the [V(IV)OV(IV)](2+) complex undergoes disproportionation and dissociation reactions to produce a solution containing an equimolar mixture of V(IV)O(salen), [V(III)(salen)](+), and [V(IV)OV(V)](3+). The oxophilic [V(III)(salen)](+) complex reacts with O(2) to accomplish a four-electron reduction of O(2): 2[V(III)(salen)](+) + O(2) --> 2[V(V)O(salen)](+). These reactions can be exploited to carry out catalytic electroreductions of O(2) to H(2)O in acidified dichloromethane solutions of V(IV)O(salen) at unusually positive potentials.