Showing papers by "Chalk River Laboratories published in 1983"
TL;DR: Examination of in vitro responses to a model environmental carcinogen of six non-tumor skin fibroblast strains from HCMM/DNS patients representing five families points to a metabolic anomaly which may contribute to the carcinogenic risk of the melanoma prone preneoplastic state presented by some DNS patients.
Abstract: The dysplastic nevus syndrome (DNS) is a preneoplastic melanocyte abnormality which occurs in families affected by hereditary cutaneous malignant melanoma (HCMM). A putative role of host-environmental interactions in the etiology of hereditary melanoma has been strengthened by the recent finding that fibroblasts derived from HCMM/DNS patients demonstrated enhanced sensitivity to u.v.-irradiation in vitro. We report here an extension of these studies in which we have examined the in vitro responses to a model environmental carcinogen, 4-nitroquinoline 1-oxide (4NQO), of six non-tumor skin fibroblast strains from HCMM/DNS patients representing five families. Three of the six HCMM/DNS strains showed enhanced cell killing with sensitivities greater than that of a xeroderma pigmentosum (XP) variant strain but less than those of ataxia telangiectasia and XP Group D cell strains. The inhibition and recovery of de novo DNA synthesis, together with the expression of repair synthesis, following 4NQO exposure appeared to be normal in HCMM/DNS strains, irrespective of their subsequent clonogenic potential. Our data point to a metabolic anomaly which may contribute to the carcinogenic risk of the melanoma prone preneoplastic state presented by some DNS patients.
36 citations
TL;DR: In this article, the effect of tensile stress on the terminal solubility of hydride-forming metal components was investigated and the results showed that hydrogen migrates up tensile strain gradients because of the effects of stress on solubilities and solusability limit.
36 citations
TL;DR: An EM algorithm procedure is presented for the maximum-likelihood estimation of mating system parameters of mixed mating system models for both angiosperms and gymnosperms, which has the ability to accommodate any number of alleles in the mature population and pollen pool.
Abstract: An EM algorithm procedure is presented for the maximum-likelihood estimation of mating system parameters of mixed mating system models for both angiosperms and gymnosperms. One advantage of the procedure is the ability to accommodate any number of alleles in the mature population and pollen pool. Estimates of the outcrossing rate (
$$\hat t$$
) derived from the model are bounded strictly within the natural biological range (i.e., 0 ≦
$$\hat t$$
≦1).
24 citations
TL;DR: In this paper, a minor isotope of the element of interest is implanted directly into the analytical sample to be utilized as a standard, and the hydrogen content determined by reference to the implanted deuterium standard was compared to a nuclear reaction analysis of the same sample.
24 citations
TL;DR: In this article, the parity nonconserving circular polarization of γ-rays from the 2.8 MeV doublet was found to be (0.8 ± 1.4) × 10^(−3), which corresponds to a parity mixing matrix element, which can be used to predict isoscalar and isovector weak nucleon-nucleon coupling constants.
21 citations
TL;DR: Three laboratories independently evaluated cultures of a woman with Turcot's syndrome for in vitro sensitivity to cell killing (loss of colony-forming ability) by x-rays consistently revealed slight but significant radiosensitivity in an early-passage fibroblast subculture.
20 citations
TL;DR: A microscopic calculation of Bohr's collective Hamiltonian was used to describe the collective motion in the 76Kr isotope as mentioned in this paper, and a single-particle basis calculated in a deformed Woods-Saxon potential leads to the potential energy surface obtained by the Strutinsky renormalization procedure, and to the inertial functions determined in the cranking model approximation.
Abstract: A microscopic calculation of Bohr's collective Hamiltonian is used to describe the collective motion in the76Kr isotope. A single-particle basis calculated in a deformed Woods-Saxon potential leads to the potential energy surface obtained by the Strutinsky renormalization procedure, and to the inertial functions determined in the cranking model approximation.
16 citations
TL;DR: In this paper, small diameter tubes of Zr-2.5 wt% Nb alloy have been tested in-reactor at 570 K for 46000 h and showed that creep is fairly linear with time both in and out of flux, that creep rates increase with increasing cold-work, and that creep anisotropy is best predicted assuming 65% prism/35% basal slip.
15 citations
TL;DR: In this article, the charge exchange between He+ and Ni(110) and adsorbed O has been studied in the energy range of a few 100 eV in comparion with Li+ scattering.
Abstract: The charge exchange between He+ and Ni(110) and adsorbed O has been studied in the energy range of a few 100 eV in comparion with Li+ scattering. The Li+ yield as a function of the scattering azimuth can be calculated neglecting neutralization effects. He+ ions in contrast undergo two different neutralization mechanisms, one being a surface electronion interaction only, the other involving very likely an interaction with bulk electrons. The second mechanism causes a very high neutralization probability for ions scattered from the second or deeper layers and for those undergoing multiple scattering trajectories. The adsorbed oxygen causes additional trajectory dependent neutralization. The azimuthal dependence of the He+ scattering from the Ni (2 × 1)O structure is described by numerical calculations for the kinematic part and a trajectory dependent neutralization model. The experimental results can only be partly reproduced by these calculations.
11 citations
TL;DR: In this paper, the effects of radiation damage induced in silicon by high energy (400 GeV) proton irradiation were studied and it was shown that radiation fluence up to 10 17 /cm 2 does not preclude deflection of high energy charged particle beams in elastically bent silicon crystals.
8 citations
TL;DR: In this paper, the measurement of particle multiplicity in a silicon detector can be used to discriminate electrons in a flux of high energy particles, and Monte Carlo simulations are compared with measurements at 4 and 15 GeV/c, for electrons and pions.
TL;DR: In this article, the density of energy (LET) deposited in a lithium target by 100 MeV protons is estimated by two methods: the continuous-slowing-down expression for the range straggling is used in a convolution with the no-straggling distribution in one method; in the other the appropriate transport integral equation is solved to first order in the straggle.