Search results for "Tritium"
showing 10 items of 165 documents
Influence of radiation defects on tritium release parameters from Li2O
1998
Abstract The study of the influence of radiation defects on tritium release behavior from polycrystalline Li2O was performed by simultaneous measurements of the luminescence emission and tritium release. It was found that the radiation defects in Li2O introduced by electron irradiation cause the retention of tritium. It is thought that the tritium recovery is affected by the formation of a Li–T bond, which is tolerant of high temperatures. The retardation of tritium decreases with increasing absorbed dose in the dose range from 50 to 140 MGy. The aggregation of radiation defects at high irradiation doses is considered to be responsible for the decrease of the interaction of tritium with rad…
On the correlation between mechanical and TEM studies of the aging of palladium during tritium storage
2005
Abstract Tritium has considerable technological applications in nuclear industry. Since it is a radioactive element, its storage is often considered in the form of tritides which ensure the required safety. However, the decay of tritium into 3 He alters the tritide properties during aging. With the aim of understanding the aging mechanisms of palladium tritide, a macroscale approach coupled with a microscopic study was performed on palladium aged up to eight months after tritium loading. The macroscale investigation based on the vibration of microcantilevers allowed the mechanical response of the material to be followed during its aging. The microscopic study was performed by Transmission E…
Novel method for determination of tritium depth profiles in metallic samples
2019
Tritium accumulation in fusion reactor materials is considered a serious radiological issue, therefore a lot of effort has been concentrated on the development of radiometric techniques. A novel method, based on gradual dissolution, for the determination of the total tritium content and its depth profiles in metallic samples is demonstrated. This method allows for the measurement of tritium in metallic samples after their exposure to a hydrogen and tritium mixture, tritium containing plasma or after irradiation with neutrons resulting in tritium formation. In this method, successive layers of metal are removed using an appropriate etching agent in the controlled regime and the amount of evo…
16α-Iodo-3,17β-estradiol: A stable ligand for estrogen receptor determinations in tissues with high 17β-hydroxysteroid dehydrogenase activity
1983
Recently, the successful synthesis of radioiodinated 16 alpha-iodo-3,17 beta-estradiol-[125I] [125I]E2 was reported [1]. This new ligand has similar binding characteristics to the estrogen receptor (ER) [2-5] as the currently used tritium labeled estradiol [3H]E2. However, it offers several advantageous features: (a) high specific activity (theoretically 2,000 Ci/mmol) [1]; (b) minor problems with radioactive waste due to its short half life and (c) the possibility of simultaneous determination of ER and progesterone receptors (PgR) by double labeling with [125I]E2 and [3H]R5020 [6, 7]. As we are presently trying to determine ER and PgR in human placental cytosols we were interested in the …
The lipoprotein lipase activity in cultured beating heart cells of the post-natal rat.
1974
Summary The lipoprotein lipase (LPL) activity was studied in cultured beating heart cells of the post natal rat as a function of the culture age, from the freshly trypsinized cell suspension up to the 14th day of culture. The LPL activity remains at a practically stationary level during the first four days of culture, and then increases rapidly to reach a plateau, at a level 3–4 times higher at the 21th day of culturing. The significance of this enzymatic activity progression comparing to 3H thymidine incorporation from the point of view of cell differentiation is discussed. Our results suggest that after the 12th day of culture, cells contain their optimal enzymatic apparatus for lipid met…
Pre- and postsynaptic effects of muscarinic agonists in the guinea-pig ileum
1980
The effects of several muscarinic agonists on smooth muscle (postsynaptic effect) and on acetylcholine release (presynaptic effect) were compared in the longitudinal muscle-myenteric plexus preparation of the guinea-pig ileum. 1. For release experiments the acetylcholine stores of the preparation were labelled with 3H-choline. Electrical field stimulation in the absence of a cholinesterase inhibitor caused an outflow of tritium that reflected release of 3H-acetylcholine. The agonists oxotremorine, arecaidinepropargylester, methylfurmethide, muscarine, carbachol, arecoline and pilocarpine inhibited the stimulation-induced outflow in a concentration-dependent manner. At the highest concentrat…
DNA-dependent DNA polymerase pattern in noninfected and herpesvirus infected rabbit kidney cells.
1973
In this paper we report on a DNA-dependent DNA polymerase produced in herpesvirus infected cells which is not present in virions. It differs from the polymerases of noninfected cells by its molecular weight as well as by its insensitivity to cytosine arabinoside triphosphate (ara-CTP).
Effects of ovariectomy and steroid replacement on GABAA receptor binding in female rat brain.
1991
Abstract The specific binding of tritiated muscimol to γ-aminobutyric acid (GABA) receptor sites was studied in distinct brain areas of female rats during different endocrine states. In diestrous rats with intact ovaries the highest receptor densities were found in the cortex (10.24 pmol/mg protein) and the lowest concentrations in the mediobasal hypothalamus (3.29 pmol/mg protein). Four weeks after removal of the ovaries, the number of binding sites was enhanced up to 2.4-fold in all brain areas investigated: the preoptic brain area, mediobasal hypothalamus, corticomedial amygdala, and cerebral cortex. The affinity of the binding sites remained unchanged. Substitution of estradiol and prog…
3H-cyproterone acetate: binding characteristics to human uterine progestagen receptors
1985
The availability of tritium labeled cyproterone acetate (CPA) facilitated the systematic investigation of the binding characteristics of this compound for human uterine progesterone receptors (PgR). The binding parameters of 3H-CPA are compared to those of 3H-R5020 and 3H-progesterone. The rate constants of association (k1M-1sec-1) to PgR were 7.8 X 10(3) for 3H-R5020, 4.5 X 10(4) for 3H-progesterone and 4.0 X 10(4) for 3H-CPA. The rate constants of dissociation (k-1, sec-1) were 3.6 X 10(-5) for 3H-R5020, 21.3 X 10(-5) for 3H-progesterone and 17.8 X 10(-5) for 3H-CPA. The Kd-values (M), as obtained by titration analysis and subsequent Scatchard plot analysis were 1.2 X 10(-9) for 3H-R5020,…
gamma-Aminobutyric acid and cholinergic transmission in the guinea-pig ileum.
1983
1. The effects of GABA on release of acetylcholine and on contractility of the smooth muscle were studied in the myenteric plexus-longitudinal muscle preparation of the guinea pig. Acetylcholine was determined as radiolabelled transmitter from strips preloaded with 3H-choline. 2. GABA (1–300 μM) caused an increase in resting tension of smooth muscle as well as an increase in release of acetylcholine that was considerably reduced by tetrodotoxin. The facilitation by GABA of acetylcholine release exhibited a marked tachyphylaxis. The increase in muscle tension was clearly related to the increase in acetylcholine release. Muscimol (0.1–10 μM) also enhanced the release of acetylcholine. The eff…