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- Author or Editor: A. Danis x
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Abstract
The possibility to obtain new information about the U/Th contamination using the patterns of the fission track micromapping is put into evidence. For the investigated samples, bed load sediments sampled from Danube river and Delta, fission track micromappings were obtained using the neutron-induced fission of the U and Th elements and the track registration of their fission fragments in muscovite track detectors. Utilising the optical microscopy, these micromappings were used both for U and Th content measurements and for studies of U/Th atom distributions. Considering the 
track micromapping pattern
as a characteristic of the U/Th atom distribution in the analysed sample, and basing on the micromapping patterns that were previously obtained for the samples contaminated in the specific conditions, the authors were able to establish: (1) the presence of the contamination of the sediments in spite of the fact that the U/Th concentration values did not exceed the natural background values, (2) the solubility of the U/Th chemical compounds in the initial waste and (3) the presence of a succession of U/Th contaminations as well as the presence of the transported contamination.
Abstract
The concentration distributions of U and Th nuclides in some sediment and algae samples from the Romanian sector of the Danube river and the Black Sea coast are presented. Data are obtained by neutron-induced fission activation analysis, epithermal instrumental neutron activation analysis and radiochemical separation using tracers followed by 
-spectrometry counting of stainless steel discs after electrodeposition. The analysing time, the working steps, the necessary equipment, the information and quality of the obtained results are discussed.
Abstract
In order to use the wood building materials in dwelling construction, uranium content measurements were performed by one of the alpha or fission track methods. The investigated samples were tree and rush samples, collected from different Romanian sites, situated in the vicinity of zones with human radioactive activities, such as: Sapantza, Izvorul Izei (North Romania), Omer and Periprava (Danube River Delta). We have examined the U atom distributions in these samples in order to detect any U contamination due to radioactivity. For each analysed sample, two U track micromappings were obtained in the two track detectors which were put in intimate contact with the sample during reactor neutron irradiations. The obtained track micromappings were studied by optical microscopy. The U distribution and content measurement results are presented and interpreted according to the present norms referring to maximum permissible values of U in building materials in Romania.
Abstract
Massive bleeding from oesophagus varices presents a life threatening complication of liver cirrhosis. No effective method of treatment is available until now, that would guarantee high grade of patient wellness during the conditioning and investigation phase until the definitive treatment could be introduced. The fact that we have not found any report in the literature about self-expandable metal stents (SEMS) application in acute variceal bleeding had encouraged us to use stents usually used for oesophageal malignancy and furthermore develop a special stent for this individual indication. The aim of this study was to evaluate the tissue response to oesophagus stent designed for stop acute variceal bleeding in animal experiment in compare with another stent used for iatrogenic treatment of different strictures of the oesophagus. Tissue oxygen saturation (StO2) measurement was performed before and after the implantation of the stents. Macroscopic and histological investigations of the stented oesophagus segments were observed after 10 days. Differential scanning calorimeter (DSC) is a well-established method for the demonstration of thermal consequences of local and global conformational changes in biological systems, but it has never been used for the investigation of the oesophagus. According to our results the thermal denaturation of intact oesophagus, its mucosa and muscle fragments revealed significant differences compared to healthy sample in favour of the new stent.
