11Beta-hydroxysteroid dehydrogenase type 2 in human pregnancy and reduced expression in intrauterine growth restriction

The evolutionary theory of aging predicts that the equilibrium gene frequency for deleterious mutations should increase with age at onset of mutation action because of weaker (postponed) selection against later-acting mutations. According to this mutation accumulation hypothesis, one would expect the genetic variability for survival (additive genetic variance) to increase with age. The ratio of additive genetic variance to the observed phenotypic variance (the heritability of longevity) can be estimated most reliably as the doubled slope of the regression line for offspring life span on paternal age at death. Thus, if longevity is indeed determined by late-acting deleterious mutations, one would expect this slope to become steeper at higher paternal ages. To test this prediction of evolutionary theory of aging, we computerized and analyzed the most reliable and accurate genealogical data on longevity in European royal and noble families. Offspring longevity for each sex (8409 records for males and 3741 records for females) was considered as a dependent variable in the multiple regression model and as a function of three independent predictors: paternal age at death (for estimation of heritability of life span), paternal age at reproduction (control for parental age effects), and cohort life expectancy (control for cohort and secular trends and fluctuations). We found that the regression slope for offspring longevity as a function of paternal longevity increases with paternal longevity, as predicted by the evolutionary theory of aging and by the mutation accumulation hypothesis in particular.     

Theoretical evaluation of viscosity of binary molten electrolytes

Significant structure theory (SST) of Eyring has been employed to calculate theoretically the viscosity of binary molten electrolytes on the basis of rigid sphere model. For KClNaCl and KClKBr systems the agreement between theoretical and experimental values is found to be satisfactory.     

Hydrostatic extrusion behaviour of high density polyethylene

The solid state processing of a high density polyethylene by hydrostatic extrusion at room temperature has been investigated. The extrusion pressure for a given extrusion ratio is found to depend on the pressure fluid used, the die angle and the velocity of extrusion. The strain hardening behaviour of the resulting extrudates is found to be independent of the extrusion ratio. An effective flow stress equation which accounts for the dependence of the flow stress of high density polyethylene on strain, strain rate and hydrostatic pressure is developed and used in an analysis of the extrusion process based on the upper bound approach. The calculated values of the extrusion pressure as a function of the various extrusion variables are in reasonable agreement with the experimental results.     

Addition polyimides. I

Crosslinking of 4,4′(bismaleimido)diphenyl ether (BM) was investigated in presence of bis(m-aminophenyl)methylphosphine oxide (BAP), tris(m-aminophenyl)phosphine oxide (TAP), diaminodiphenyl ether (E) and 3,3-bis(p-aminophenyl)phthalide (AP). These crosslinked resins were examined for thermal stability by thermogravimetric analysis. A slight decrease in initial decomposition temperature, the temperature of maximum rate of weight loss, was observed, though the char yield in nitrogen atmosphere at 800°C did not change appreciably. Glass-cloth-reinforced laminates were fabricated from BM and amine mixtures. An improvement in mechanical properties was observed in the presence of phosphorus-containing di- and triamines.     

Spectral selectivity and accelerated life testing of Al-PbS solar selective surfaces

High absorptance and low thermal emittance selective surfaces have been formed by evaporating lead sulphide onto Al evaporated Al substrates. The dependence of selectivity, α/?, on thickness has been studied. The maximum selectivity was obtained for PbS thickness of 400 Å. The emissivity is found to increase with temperature. The coatings are stable up to a temperature of 240°C in air. Long term ultraviolet irradiation causes the photo-oxidation of PbS to PbSO₄ which results in the increase of emittance and a decrease in absorptance. When cycled between 0°C and 200°C, the coatings do not show any signs of degradation.     

Evaluating the impact of thermal and pressure treatment in preserving textural quality of selected foods

A study was conducted to evaluate the efficacy of various combinations of pressure and thermal treatments in preserving textural quality of selected foods. Carrot, zucchini, apricot, red radish, and jicama were used as test samples. Pressure-assisted thermal processing (PATP; 600 MPa, 105 °C), high-pressure processing (HPP; 600 MPa, 25 °C), and thermal processing (TP; 105 °C, 0.1 MPa) experiments were conducted. Role of pressure (600 MPa) in preserving product quality while simultaneously (PATP) or sequentially (HPP-TP) exposed to elevated process temperature (105 °C) was also compared. Instrumental puncture, shear force, color and sensory analyses were utilized to compare the influence of the various process treatments. A crunchiness index (CI), relating product puncture force and stiffness, was able to characterize the severity of the process treatments on various products tested. Among the treatments, TP was the worst at retaining texture, but HPP-TP improved texture retention. In comparison to TP alone, PATP better retained texture and color. Jicama was least influenced by the treatments as compared to products tested. Process treatments investigated degraded the textural quality of zucchini and apricot. Instrumental CI results were also in agreement with the sensory data of carrot, red radish and jicama samples.     

Thermal post-buckling analysis of slender columns using the concept of coupled displacement field

Thermal post-buckling analysis of columns with an axially immovable ends is studied using the Rayleigh-Ritz (R-R) method, where the admissible displacement functions are chosen based on the concept of coupled displacement field (CDF) criteria. Geometric non-linearity is considered using the von-Karman strain displacement relations of the beam. Furthermore, the displacement fields derived from CDF criteria are used in an intuitive formulation, where the thermal post-buckling behavior can be predicted by using two parameters namely tension developed in the column and linear buckling load. An exhaustive set of column boundary conditions are considered namely classical such as hinged-hinged, clamped-clamped, clamped-hinged and non-classical such as clamped-guided and hinged-guided. Post-buckling analysis results are presented in the form of closed form expressions, where the ratio of post-buckling load to linear buckling load parameter is expressed as a function of central amplitude of the column for all the boundary conditions considered. The amount of non-linearity predicted using the present formulations (R-R method and intuitive method) based on the concept of coupled displacement field (CDF) criteria shows an excellent agreement with the available literature results for both classical and non-classical boundary conditions.