Search Results
. Geography of Hungary (In Hungarian) . Tankönyvkiadó . Buda-pest . F üleky , G. , 2005 . Soils of the Bronze Age tell in Százhalombatta . In: SAX, Százha
Abstract
The Ca, Cl, K, Mg, Na, P, and Sr concentration of rib-bone was studied of 78 relatively healthy 15–55 years old women and men using instrumental neutron activation analysis. A tendency for Ca, P, and Mg concentrations to decrease with age was found in subjects over 35 which was manifested more distinctively in women. It was shown that higher volumes of density, Ca and P concentrations as well as lower K, Cl, and H2O contents were typical of female ribs being compared to those in male ribs. The average annual losses of the rib Ca in the Russian women over 25 were estimated to be 0.7% of the concentration peak level. They agree well with data available for citizens of the USA and Germany.
Abstract
The time course and defining factors involved in the formation of neurofibrillarytangles (NFT) and senile plaques (SP) in Alzheimer's disease (AD) brainare unknown. Above ground nuclear weapons tests led to significantly increasedlevels of 14C in the carbon cycle. Because SP and NFT are relativelyresistant to degradation, the 14C levels in SP and NFT should reflecttheir year of formation. Through the use of accelerator mass spectrometry(AMS) and the measurement of 14C levels, we have determined theaverage age of formation of isolated SP and NFT fractions of 6 AD subjects.While a heterogeneous process of formation is indicated, NFT pre-date SP inthe majority of cases. In addition, it is clear that NFT and SP have a muchslower carbon turnover rate than normal brain tissue.
Abstract
The core samples of oil- and bitumen-containing rocks from Tatarstan's deposits of different ages were studied by thermal analysis methods (DTA, TG, DTG). Based on the obtained data, a procedure was elaborated for determining the enclosed organic matter content and the index of its fraction composition. A significant increase of the organic matter content in the core and its enrichment in high-molecular aromatic structures were shown to occur for the oil-containing rock samples when passing from the Devonian to Carboniferous and Permian deposits. The core samples of the Devonian oil-containing rocks may be divided into three groups: the samples taken from the zones where waste water flooding has been started relatively recently (1), or fresh water flooding has been carried on for a long time (2) and the samples of rock containing clay minerals as impurities. Thus, thermal analysis can be used in geochemical studies to identify the organic matter enclosed by oil- and bitumen-containing rocks.
Abstract
The spallogenic radionuclides26Al (T=7.18·105 a) and53Mn (T=3.8·106 a) were determined in 11 ordinary chondrites and 7 achondrites from Antarctica by nondestructive coincidence counting techniques and radiochemical neutron activation analysis, respectively. The results are discussed with respect to exposure ages, terrestrial residence times and possible genetic relationships of the meteorites investigated. The high terrestrial ages of some specimens (up to 800 000 years) are of importance for the study of the ice flow in Antarctica.
Abstract
The effect of age on chemical element contents in intact prostate of 64 apparently healthy 13–60 years old men was investigated by neutron activation analysis with high resolution spectrometry of short-lived radionuclides. Mean values (M ± SΕΜ) for content (mg/kg, dry weight basis) of chemical elements were: Br–31.6 ± 3.2, Ca–2150 ± 160, Cl–12670 ± 675, K–12010 ± 400, Mg–1150 ± 75, Mn–1.56 ± 0.09, and Na–10520 ± 340, respectively. A tendency of age-related increase in Ca content and decrease in Mn content was observed.
Abstract
Positron annihilation lifetime spectroscopy was used to study the time dependence of the ortho-positronium lifetime and intensity and the ortho-positronium lifetime distribution in a poly(ethylene oxide)/poly(methyl methacrylate) blend after heat treatment. The recently introduced maximum entropy for lifetime analysis (MELT) program and the POSITRONFIT program were used for evaluation of the spectra. The blend shows a large excess in free volume hole size shortly after cooling from the melt. Withi time, the hole size decreases, while the orthio-positronium intensity remains constant. The lifetime distribution width does njot vary systematically with time. Differential scanning calorimetry measurements show that crystallisation of the poly(ethylene oxide) phase occurs parallel to the decrease in ortho-positronium lifetime.
Abstract
The sodium-to-calcium ratios were determined by INAA in sections of human bone. The values found in three age groups of male individuals were as follows: 21–30 years: Na/Ca ratio of 0.01858, 41–50 years: Na/Ca ratio of 0.02117, >60 years: Na/Ca ratio of 0.002208. The differences are discussed considering former results of the authors concerning the Na–to–Ca ratio in the bone mineral.
