The Influence of Skin Temperature on Dermal-Epidermal Adherence: Evidence Compatible with a Highly Viscous Bond

The influence of skin temperature on dermal-epidermal adherence was investigated. The adherence was measured by eliciting suction blisters; blistering time was determined under controlled skin temperature. In the range of skin temperatures investigated (20°–43° C) the adherence decreases continuously with increasing temperature. Adherence is, approximately, an exponential function of temperature; an increase of skin temperature by 10° C decreases blistering time by a factor of about 4. This type of relationship supports the hypothesis that epidermis and dermis are connected by a viscous bond. The strong influence of skin temperature suggests that a high viscosity is involved

Weak capture of protons by protons

The cross section for the proton weak capture reaction $^1H(p,e^+\nu_e)^2H$ is calculated with wave functions obtained from a number of modern, realistic high-precision interactions. To minimize the uncertainty in the axial two-body current operator, its matrix element has been adjusted to reproduce the measured Gamow-Teller matrix element of tritium $\beta$ decay in model calculations using trinucleon wave functions from these interactions. A thorough analysis of the ambiguities that this procedure introduces in evaluating the two-body current contribution to the pp capture is given. Its inherent model dependence is in fact found to be very weak. The overlap integral $\Lambda^2(E=0)$ for the pp capture is predicted to be in the range 7.05--7.06, including the axial two-body current contribution, for all interactions considered.Comment: 17 pages RevTeX (twocolumn), 5 postscript figure

A dose-response model for skin cancer induction by chronic u.v. exposure of a human population

A dose-response model, based on the results of animal experiments, is presented for skin cancer induction in a human population by chronic exposure to ultraviolet radiation. The model takes into account a variety of exposure habits and susceptibilities of the individuals in the population. The required input data for the dose-response relationship are the age specific incidences of the population in question. Calculations based on this model can be used as a step in the evaluation of the effect which a reduction of stratospheric ozone would have on the non-melanoma skin cancer incidence. As an example an evaluation for the white population of the U.S.A. is presented. The estimate resulting from this evaluation agrees fairly well with earlier estimates based on combined climatological and epidemiological data

The reaction 25Mg (p,[gamma]) 26Al (I experimental)

Energies and intensities have been measured of γ-rays produced in the 25Mg(p, γ)26Al reaction at six resonances in the region Ep = 0.3 − 0.7 MeV. Thin enriched 25Mg targets were bombarded with protons from a Cockroft-Walton generator, and γ-rays were detected with a scintillation spectrometer. The resulting pulse spectra were analyzed with a differential discriminator and photographed on an oscilloscope screen. The resonances investigated here could be assigned to 25Mg by comparison with runs on enriched 24Mg and 26Mg targets. The 25Mg resonances are found at 321, 395, 441, 501, 518, 580, 607, 667 and 688, all ± 15 keV. The 501 and 518 keV resonances could not be resolved completely, but they show almost identical γ-ray spectra. The resonances at 667 and 688 keV have not been investigated in detail. The six resonances investigated in detail show complicated γ-ray spectra, different from resonance to resonance. A list of γ-ray energies and intensities is given in Tables II and III. From absolute γ-ray yield measurements the radiation widths of all resonances (multiplied by a statistical factor) could be determined

The reaction 25Mg (p,[gamma]) 26Al (II conclusions)

The measurements described in the preceding paper (I) are used to obtain the position, spin and isobaric spin of energy levels in 26Al. All the observed intensive high-energy γ-rays can be explained as transitions from resonance levels to the levels found by Browne 7) from the 28Si(d, a) 26Al reaction and to one additional level at Ex = 2.57 ± 0.04 MeV. The low-energy γ-rays fit the same level scheme, plus one more additional level at Ex = 0.235 ± 0.009 MeV. The latter level is actually the first excited state in 26Al, which turns out to be an isomeric state decaying by β+ emission with the long known half life of 6.6 sec. Spins J, parities and isobaric spins T can be assigned as follows: Ex = 0 (J = 5+, T = 0), Ex = 0.235 MeV (J = 0+, T = 1), Ex = 0.419 MeV (J = 3+, T = 0), Ex = 1.055 MeV (J = 1+, T = 0), Ex = 1.750 MeV (J = 2+, T = 0), Ex = 2.064 MeV (J = 2+, T = 0). The resonance level at Ex = 6.73 MeV has J = 4−, T = 0. Tentative assignments to the other resonance levels will be discussed. The 6.6 sec β+ decay is remarkable by being one of the few known 0+ → 0+ transitions. The β+ endpoint can best be arrived at by using a cycle involving the 0.820 MeV γ-ray from 25Mg(p, γ)26Al, the Q-value of the 28Si(d, a) 26Al transition to the 1.055 MeV level in 26Al, and a reevaluation of the 28Si-26Mg mass difference. This yields Eβ+ = 3.225 ± 0.015 MeV, and ft = 3200 ± 80 sec. The ft value of this β+ transition can now be used for direct evaluation of the Fermi coupling constant gF. The result is: gF = (1.391 ± 0.017) × 10−49 erg cm3