DYNAMICS OF INDICES OF OXIDATIVE STRESS IN PATIENTS WITH THYROID GLAND SURGERY DEPENDING ON ITS FUNCTIONAL ACTIVITY

Hormonal dysfunction of the thyroid gland causes disorder of all kinds of metabolism. Both hypothyroidism, and hyperthyroidism are the causes of imbalance in prooxidant-antioxidant system with the development of pathological process named "oxidative stress". Objective - study of oxidative stress in patients who underwent thyroid gland operation depending on its functional activity and the presence of autoimmune thyroiditis. The intensity of lipid peroxidation was examined by concentration of diene conjugates and malondialdehyde, and the activity of antioxidant system by the level of catalase, superoxide dismutase, glutathione peroxidase, glutathione reductase of red blood cells. It was established that the activity level of the lipid peroxidation system and the activity of antioxidant defense enzymes have their specific characteristics depending on the various functional states of the thyroid gland, as well as on the presence or absence of autoimmune component in the structure of thyroid pathology. All changes occurring in patients with this pathology accompanied by hormonal imbalance and autoimmune thyroiditis, lead to development of chronic nonspecific metabolic endogenous intoxication.

First experiments with the negative ion source NIO1

Neutral Beam Injectors (NBIs), which need to be strongly optimized in the perspective of DEMO reactor, request a thorough understanding of the negative ion source used and of the multi-beamlet optics. A relatively compact radio frequency (rf) ion source, named NIO1 (Negative Ion Optimization 1), with 9 beam apertures for a total H(-) current of 130 mA, 60 kV acceleration voltage, was installed at Consorzio RFX, including a high voltage deck and an X-ray shield, to provide a test bench for source optimizations for activities in support to the ITER NBI test facility. NIO1 status and plasma experiments both with air and with hydrogen as filling gas are described. Transition from a weak plasma to an inductively coupled plasma is clearly evident for the former gas and may be triggered by rising the rf power (over 0.5 kW) at low pressure (equal or below 2 Pa). Transition in hydrogen plasma requires more rf power (over 1.5 kW).

Installation of a versatile multiaperture negative ion source

Neutral Beam Injectors (NBI), which need to be strongly optimized in the perspective of DEMO reactor, request a thorough understanding of the negative ion source used and of the multi-beamlet optics. A relatively compact RF ion source, named NIO1 (Negative Ion Optimization 1), with 9 beam apertures for a total H(-) current of 130 mA, 60 kV acceleration voltage, is being installed at Padua, in Consorzio RFX, to provide a test bench for source optimizations in the framework of the accompanying activities in support to the ITER NBI test facility. NIO1 construction and status of the overall installation, including a high voltage deck and an optical cavity ring down spectrometer are here summarized and reported. Plasma and low voltage beam operations are discussed. Development of a sampling beam calorimeter (with small sampling holes, and a segmented cooling circuit) is also discussed.

Development of a versatile multiaperture negative ion source

A 60 kV ion source (9 beamlets of 15 mA each of H(-)) and plasma generators are being developed at Consorzio RFX and INFN-LNL, for their versatility in experimental campaigns and for training. Unlike most experimental sources, the design aimed at continuous operation. Magnetic configuration can achieve a minimum ∣B∣ trap, smoothly merged with the extraction filter. Modular design allows for quick substitution and upgrading of parts such as the extraction and postacceleration grids or the electrodes in contact with plasma. Experiments with a radio frequency plasma generator and Faraday cage inside the plasma are also described.

Models of radiofrequency coupling for negative ion sources

Radiofrequency heating for ICP (inductively coupled plasma) ion sources depends on the source operating pressure, the presence or absence of a Faraday shield, the driver coil geometry, the frequency used, and the magnetic field configuration: in negative ion source a magnetic filter seems necessary for H(-) survival. The result of single particle simulations showing the possibility of electron acceleration in the preglow regime and for reasonable driver chamber radius (15 cm) is reported, also as a function of the static external magnetic field. An effective plasma conductivity, depending not only from electron density, temperature, and rf field but also on static magnetic field is here presented and compared to previous models. Use of this conductivity and of multiphysics tools for a plasma transport and heating model is shown and discussed for a small source.

ITEP MEVVA ion beam for rhenium silicide production

The rhenium silicides are very attractive materials for semiconductor industry. In the Institute for Theoretical and Experimental Physics (ITEP) at the ion source test bench the research program of rhenium silicide production by ion beam implantation are going on. The investigation of silicon wafer after implantation of rhenium ion beam with different energy and with different total dose were carried out by secondary ions mass spectrometry, energy-dispersive x-ray microanalysis, and x-ray diffraction analysis. The first promising results of rhenium silicide film production by high intensity ion beam implantation are presented.

Design of a versatile multiaperture negative ion source

Negative ion sources are a key component of the neutral beam injector to be installed in the International Thermonuclear Experimental Reactor. At present research and development activities address several important issues related to beam extraction, optics, and optimization. Together with the design of real size devices and the accumulation of atomic cross section databases, a relatively small negative ion source [130 mA of H(-) at 60 kV, named Negative Ion Optimization phase 1 (NIO1)] is under construction at Consorzio RFX to contribute to benchmark numerical simulation tools and to test components, such as emittance scanners, beam dumps, and cesium ovens. NIO1 design, magnet configuration, and rf coupling simulations are described.

Refractory rf ovens and sputter probes for electron cyclotron resonance ion source

Beams from electron cyclotron resonance ion source (ECRIS) with radio frequency ovens for refractory material (using a Mo coil) were recently demonstrated; results for Ti and V are here discussed, with temperature T(s) > or = 2300 K stably maintained and extracted current of about 1000 nA for V(8+) and V(9+). The status of sputter probes is also reported, and the reason why trapping efficiency may be lower than in the oven case are investigated. The simple tubular probe concept show typical currents of Sn(18+) about 250 nA, for the most abundant isotopes, but an operating pressure of about 300 microPa may be required. Some preliminary experiments were performed with Penning probes, showing that transmission of Sn or Pr from Penning cathode to ECRIS plasma is limited. Placement of tin onto anticathode and use of collimator between Penning and ECRIS are also discussed.

Iodine nutrition and the risk from radioactive iodine: a workshop report in the chernobyl long-term follow-up study

The major fallout of radionuclides from the nuclear power station accident at Chernobyl on 26 April, 1986, occurred in regions of Ukraine and Belarus that are believed to be moderately deficient in dietary iodine. On 17 November, 2000, in conjunction with the Ukraine-Belarus-USA study of developing thyroid disease in a cohort of individuals exposed as children, a workshop was held to review what is known about iodine nutrition in the region, how this might influence the risk of thyroid tumor formation from radioiodine, and whether and how iodine nutrition should be monitored in this long-term project. This report is a summary of the workshop proceedings. Although no precise information about iodine intake in 1986 was found, the prevalence of mild goiter in the region's children suggested iodine deficiency and urinary iodine measurements begun in 1990 indicated that mild to moderate deficiency existed. Increased thyroid iodine uptake and increased thyroid size in 1986 resulting from iodine deficiency would have had counteracting influence on the thyroid radiation dose and knowledge of these parameters is required for dose reconstruction. More problematic is the possible role of iodine deficiency in the years following the accident. Theoretically, the resulting increase in thyroid cellular activity might increase the risk of tumorigenesis but experimental or clinical evidence supporting this hypothesis is meager or absent. Despite this limitation it was considered important to monitor iodine nutrition in the cohort subjects in relation to their place of residence and over time. Methods to accomplish this were discussed.

Iodine deficiency in Belarusian children as a possible factor stimulating the irradiation of the thyroid gland during the Chernobyl catastrophe

Ten years after the Chernobyl nuclear plant catastrophe more than 500 children in Belarus are suffering from thyroid cancer. The major cause of the high incidence of thyroid cancer in children under 15 years of age appears to be contamination resulting from that catastrophe, mainly with isotopes of radioactive iodine. Another important factor may be iodine deficiency in the environment. A countrywide program for investigation of goiter prevalence and iodine deficiency has been established in the Republic of Belarus with the assistance of the European World Health Organization office. The program will oversee the examination of 11,000 children and adolescents 6 to 18 years of age from 30 schools in urban and rural areas. The results obtained in a group of 824 children and adolescents (the pilot phase) are typical for significant iodine deficiency and moderate goiter endemism. It is clear that the present situation does not completely reflect the situation that existed at the time of the Chernobyl catastrophe. However, data from epidemiologic studies conducted many years before the accident showed high goiter prevalence in the contaminated areas, indicating that the prevalence of iodine deficiency at the time of the catastrophe was similar to the present one or even greater. Such an assumption could lead to a better understanding of the thyroid pathologies that have been observed.

Chromosome aberrations in human lymphocytes apparently induced by Chernobyl fallout

Sixteen people (15 from Byelorussia, one from Kiev) possibly exposed to radioactivity released by the Chernobyl accident were investigated for chromosome aberrations induced in lymphocytes. Statistically significant increases of the yield of dicentric chromosomes were observed in five people.

Neuropeptide Y inhibits forskolin-stimulated adenylate cyclase activity in rat hippocampus

Neuropeptide Y inhibited the forskolin-stimulated adenylate cyclase activity in rat hippocampus with the half-maximal effect occurring at 73 nM. The maximal inhibition corresponded to a 17-22% decrease of the control level of enzyme activity. The effect of neuropeptide Y was mimicked by the peptide YY but not by the avian pancreatic polypeptide and required micromolar concentrations of GTP. These results indicate that, in the brain, the inhibition of adenylate cyclase activity constitutes a mechanism by which the receptor for neuropeptide Y transduces its signal.