Experimental determination of the energy dependence of defect production

A knowledge of primary damage production as a function of recoil energy is essential for predicting defect production in radiation environments of practical interest. The damage function $\text{ν(T)}$, i.e., the number of Frenkel pairs as a function of recoil energy, is determined for Cu from electron and ion damage-rate measurements. $\text{ν(T)}$ shows a plateau at $\text{ν = 0.54}$ which extends up to ~ $\text{7T}{}_{\mathrm{d}}{}^{\min }$. Therefore, simple damage models, such as the modified Kinchin-Pease expression, are strongly deficient, not only at high recoil energies where stimulated recombination in cascades reduces defect production, but also in the single displacement regime. As a consequence, no simple relation between $\text{T}{}_{\mathrm{d}}{}^{\min }$ and $\text{T}{}_{\mathrm{d}}{}^{\mathrm{av}}$ is expected to exist. A procedure is suggested which uses anisotropy measurements in combination with polycrystal electron and ion irradiations to construct absolute damage functions in metals.     

Clinical subgroup of autoimmune hepatitis type 1 sustaining remission without additional drugs

BACKGROUND/AIMS: Many patients with autoimmune hepatitis type 1 need additional non-steroidal immunosuppressants to maintain remissions, but the indication should be limited to avoid the unnecessary side effects. The aim of this study is to clarify the clinical subgroups of autoimmune hepatitis type 1 sustaining remission without additional drugs. METHODOLOGY: We studied 20 patients with autoimmune hepatitis type 1, in whom complete remissions were achieved in the natural course or by prednisolone alone. Remissions were maintained with none or less than 10 mg/day of prednisolone. RESULTS: In the course (average: 6 years), 8 patients (40%) remained in remission for more than three years. In the remitted group, initial values of serum gamma-globulin (p<0.05) and serum immunoglobulin G (p<0.01) were lower than those in the relapsed group. The group with less than 30 mg/ml of gamma-globulin and 3000 mg/dl of immunoglobulin G showed a significantly lower relapse rate than the other one (p<0.01). CONCLUSIONS: There is a clinical subgroup of autoimmune hepatitis type 1 that sustains remission with low-dose prednisolone alone. Additional immunosuppressive drugs may not be needed to maintain remissions in such patients.     

Constitutive production of aconitate isomerase by Pseudomonas sp. WU-0701 in relation to trans-aconitic acid assimilation

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Bogoliubov Theory for a Superfluid Bose Gas Flowing in a Random Potential: Stability and Critical Velocity

We investigate the stability and critical velocity of a weakly interacting Bose gas flowing in a random potential. By applying the Bogoliubov theory to a disordered Bose system with a steady flow, the condensate density and the superfluid density are determined as functions of the disorder strength, flow velocity, and temperature. The critical velocity, at which the steady flow becomes unstable, is calculated from the spectrum of hydrodynamic excitation. We also show that in two dimensions the critical velocity strongly depends on the system size.     

A measurement of very fast transition durations due to gapdischarge in air using distributed constant line system

Very fast transition durations (rising time in positive polarity and falling time in negative polarity) due to starting of gap discharge were investigated in time domain. The gap space was set very small for voltages below 1500 V as a simulation of the charged device model (CDM) electrostatic discharge (ESD) and the gap discharge of switch devices. The measurement system consists of a distributed constant line system with a tapered coaxial electrode, which has a matched impedance for the characteristic impedance of the distributed constant line system. The insertion loss of the tapered coaxial electrode was within -3 dB in the frequency range below 4.5 GHz. The atmosphere around the electrode is ordinary air. This experimental system enables one to measure the high-speed transients of about 100 ps due to gap discharge in time domain. As a consequence of the experiment, the relationship between the discharge voltage and transition duration was confirmed. The voltage rise time was slowed down gradually in positive polarity, while the voltage fall time was slowed down remarkably in negative polarity for the 0.1-mm needle     

Desensitization of human muscarinic acetylcholine receptor m2 subtypes is caused by their sequestration/internalization

The most popular pretreatment method of plasma samples for the measurement of ascorbate (AsA) and dehydroascorbate (DHA) has been an acidic deproteinization via metaphosphoric acid or trichloroacetic acid. In general, DHA is absent in plasma samples prepared from human blood in a conventional manner. However, when these plasma samples were subjected to acidic deproteinization, DHA was detected in the acidified sample solutions. In the present study, we demonstrate that the oxidation of AsA to DHA in the solutions was promoted by at least two mechanisms, one involving catalysis by ferric ion released from transferrin, and the other involving catalysis by plasma hemoglobin. In the acidified transferrin solution by trichloroacetic acid, an oxidation of AsA to DHA proceeded with standing time, whereas the oxidation was not observed in that by metaphosphoric acid. This oxidation appeared to be catalyzed by ferric ion released from transferrin. In contrast, plasma hemoglobin functioned as a catalyst for AsA oxidation in both metaphosphoric acid and trichloroacetic acid solutions. Therefore, DHA content in the trichloroacetic acid-treated plasma sample was markedly higher than that in the metaphosphoric acid-treated one. These results suggest that DHA detected in acidified plasma samples is an artifact resulting from AsA oxidation.     

Reproduction of progressive retinal degeneration (bright blindness) in sheep by administration of ptaquiloside contained in bracken

The process of occurrence of bright blindness, progressive retinal degeneration (PRD), in sheep was observed using two Suffolk ram lambs fed on a diet containing bracken powder. The first sign of the bright blindness was detected 4 months after the start of experiment. Based on these preliminary results, the amount of bracken powder necessary to induce PRD was estimated (experiment I). In the following experiment, ptaquiloside (PT), a norsesquiterpene glucoside of the illudane type isolated from bracken, which is a bracken carcinogen and a causative principle of cattle bracken poisoning was administered to two Suffolk ram lambs. It was clearly demonstrated in this experiment (experiment II) that PT present in bracken is also a causative principle of PRD.     

Rheumatoid arthritis and the risk of malignancy

OBJECTIVE: To determine the relative risks of malignancy and of site-specific malignancies in patients with rheumatoid arthritis (RA). METHODS: In a prospective cohort study, 862 patients with RA (96% white) were enrolled from 1966 to 1974 and were followed up for up to 35 years (mean 17.4 years) at the University of Saskatchewan Rheumatic Disease Unit. All diagnoses of cancer were cross-referenced with the Provincial Cancer Registry. Expected cancer incidence rates were determined based on province of Saskatchewan population statistics matched to each study patient for age, sex, and calendar year. Standardized incidence ratios (SIRs) of the observed-to-expected cancer incidence and 95% confidence intervals (95% CI) were then calculated. RESULTS: A total of 136 cases of cancer were observed compared with 168 expected (SIR 0.80, P = 0.011 [95% CI 0.67-0.95]). The relative risk of colorectal malignancy was significantly reduced in the RA study population (SIR 0.52, P = 0.037 [95% CI 0.25-0.96]). A significant excess of leukemia was found (SIR 2.47, P = 0.026 [95% CI 1.12-4.69]), whereas the incidence rates for Hodgkin's disease and non-Hodgkin's lymphoma and all other site-specific malignancies were not found to be significantly different from general population rates. CONCLUSION: In our cohort of RA patients, colorectal cancer was detected in only half the expected number of patients. This risk reduction may be related to long-term nonsteroidal antiinflammatory drug (NSAID) use in RA, as has been suggested in several other studies of long-term NSAID use. An increased risk of leukemia was confirmed. This may be due to the persistent immune stimulation associated with RA itself, since other potential explanatory factors for increased leukemia were not apparent. Despite the excess of hemopoietic malignancy and despite treatment of RA with potentially oncogenic agents, the overall risk of malignancy was reduced in this RA cohort.