ENERGY RESPONSE OF FLUORESCENT NUCLEAR TRACK DETECTORS OF VARIOUS COLORATIONS TO MONOENERGETIC NEUTRONS.

The neutron-energy dependence of the track-counting sensitivity of fluorescent nuclear track detectors (FNTDs) at two ranges of Mg doping, resulting in different crystal colorations, was investigated. The performance of FNTDs was studied with the following converters: Li-glass for thermal to intermediate-energy neutrons, polyethylene for fast neutrons, and polytetrafluoroethylene (Teflon™) for photon- and radon-background subtraction. The irradiations with monoenergetic neutrons were performed at the National Physics Laboratory (NPL), UK. The energy range was varied from 144 keV to 16.5 MeV in the personal dose equivalent range from 1 to 3 mSv. Monte Carlo simulations were performed to model the response of FNTDs to monoenergetic neutrons. A good agreement with the experimental data was observed suggesting the development of a basic model for future MC studies. Further work will focus on increasing FNTD sensitivity to low-energy neutrons and developing a faster imaging technique for scanning larger areas to improve counting statistics.

CHARACTERIZATION OF FLUORESCENT NUCLEAR TRACK DETECTORS AS CRITICALITY DOSIMETERS II.

Fluorescent nuclear track detectors (FNTDs) as criticality dosimeters for both neutrons and gamma are further characterized in terms of angular dependence and quick dose assessment. The power spectrum integral depth profiles obtained from stacks of fluorescent images acquired within FNTDs exposed to a broad spectrum neutron field at various angles are analyzed to determine a calibration curve for angular dependence. MCNPX simulations were shown to be in good agreement with experimental results. A prototype triage reader was also designed and tested for quick assessment of dose. An unfolding technique incorporating both energy dependence and angular dependence is discussed. The advantages and shortcomings of using FNTDs in the event of a criticality excursion accident are analyzed.

COMPARISON BETWEEN PADC AND FNTD NEUTRON DETECTOR SYSTEMS IN BLIND TESTS.

The objective of this study was to compare a neutron dosimetry system based on polyallyl diglycol carbonate (PADC) detectors with a new system based on Al2O3:C,Mg fluorescence nuclear track detectors (FNTD). The irradiations, performed as part of an intercomparison organized by the Physikalisch-Technische Bundesanstalt (PTB), Germany, were on a PMMA phantom with 252Cf or 241Am-Be source, usually with the phantom surface perpendicular to the radiation beam (0° angle), and with Hp(10) values between 0.3 and 7 mSv. One 252Cf irradiation was performed at 30° angle, and one with an additional 1 mSv gamma irradiation. The results showed an agreement between the two techniques with an average and maximum difference between PADCs and FNTDs of 1.5 and 22%, respectively, if one compares only cases of doses >1 mSv. For one of the irradiation conditions with dose of 0.9 mSv, use of the incorrect calibration factor for the FNTD (252Cf instead of 241Am-Be) led to reported values ~×2 larger than the given doses, due to low statistics in the determination of the ratio between 6Li-doped glass and polyethylene neutron converters. Although the FNTD track analysis algorithm may need further development, the results presented here demonstrate the feasibility of the FNTD technology and indicate areas requiring improvements.

Automatic neutron dosimetry system based on fluorescent nuclear track detector technology.

For the first time, the authors are describing an automatic fluorescent nuclear track detector (FNTD) reader for neutron dosimetry. FNTD is a luminescent integrating type of detector made of aluminium oxide crystals that does not require electronics or batteries during irradiation. Non-destructive optical readout of the detector is performed using a confocal laser scanning fluorescence imaging with near-diffraction limited resolution. The fully automatic table-top reader allows one to load up to 216 detectors on a tray, read their engraved IDs using a CCD camera and optical character recognition, scan and process simultaneously two types of images in fluorescent and reflected laser light contrast to eliminate false-positive tracks related to surface and volume crystal imperfections. The FNTD dosimetry system allows one to measure neutron doses from 0.1 mSv to 20 Sv and covers neutron energies from thermal to 20 MeV. The reader is characterised by a robust, compact optical design, fast data processing electronics and user-friendly software.

[Patients' self assessment of postop results after reconstructive surgeries on the femoral-popliteal segment of the arteries and their rehabilitation]. / Samootsenka patsientami iskhodov rekonstruktivnykh operatsii na bedrenno-podkolennom segmente arterii i ikh posleoperatsionnaia reabilitatsiia.

A comparative analysis of long-term results of reconstructive operations on the femoro-popliteal segment performed by different techniques was based on the assessment of the operation results made by the patients and their social rehabilitation after the operation. The operations of choice may be thought to be reconstruction with the application of transplants of velours dacron with a gelatin impregnation (VDGI), polytetraftoroethylene (PTFE) and autovein. Transplants of VDGI are found to be preferable. The long-term results of using PTFE transplants in the femoro-popliteal position were shown by the authors to be inferior to VDGI transplants. Since PTFE is much more expensive than dacron, the practice of so wide using this material should be revised. The authors believe that endarterectomy can not be considered to be the operation of choice for long-standing occlusions of the superficial femoral artery. They should be used but for critical ischemia of the extremity when trying to safe it if the transplants of VDGI and PTFE and good autovein are not available. The long-term results of using lavsan-ftorolon transplants in the femoro-popliteal position suggest that they should not be used in practice.

[Correlation of extremity safety and method of reconstructive surgery on femoral-popliteal segment]. / Zavisimost' sokhrannosti konechnosti ot metoda rekonstruktivnoi operatsii na bedrenno-podkolennom arterial'nom segmente.

Long-term results of 660 reconstructive surgeries on the arteries of femoral-popliteal segment have been analyzed. In critical limb ischemia surgeries with PTFE grafts are most effective - in 5 years 77.1% of extremities were saved compared with 69.6% after autovenous reconstructions. Use of gelatinized velour dacron (GVD) grafts (when PTFE or autovenous grafts are absent) permits to save 62.4% of extremities in 5 years. Endarterectomies (EAE) and bypass surgeries with fluorolavsan (FL) grafts should not be regarded as surgeries of choice in critical limb ischemia. Safety of limbs after surgeries with PTFE, GVD and autovenous grafts performed in the stage of claudication does not differ significantly. Cumulative safety of extremities after EAE and bypass with FL grafts is worse but high. In the first month after surgery 29.3% of all amputations were performed, in the first six months - 47.8%.

[Surgical policy in combined occlusion of femoral-popliteal and aorto-iliac-femoral segments in occlusive diseases of lower limb arteries]. / Khirurgicheskaia taktika pri sochetanii okkliuzii bedrenno-podkolennogo aortopodvzdoshno-bedrennogo segmenta pri obliteriruiushchikh zabolevaniiakh arterii nizhnikh konechnostei

Long-term results of 169 reconstructive surgeries for occlusions of femoral-popliteal segment in combination with occlusions and stenosis of aorto-iliac-femoral segment (AIFS) were analyzed retrospectively. Better results were achieved in simultaneous reconstruction of both segments with vascular grafts. Correction of inflow ways with endarterectomy is not expedient. It is necessary to expand indications for surgical correction of AIFS stenosis. Surgery on arteries of AIFS must be performed when angiography demonstrates stenosis of iliac arteries more than 30% or stenotic murmur is auscultated in projections of these vessels.

[Femoro-popliteal reocclusion. Obligatory reoperation?]. / Bedrenno-podkolennye reokkliuzii. Vsegda li reoperatsiia?

The paper presents 408 cases of femoro-poptiteal reocclusion. The effectiveness of 202 reoperations is analyzed. Authors give definition of repeated operations and restitution of secondary patency in femoro-popliteal segment. Repeated operation is a special entity differing from initial one and including graft exchange, occasionally of the same construction. Secondary patency is a restitution of blood flow without graft or operation type exchange. Effectiveness of reoperations appeared to depend on initial intervention type, timing and grade of lower limb ischemia. The analysis of this correlation served the basis for development of reoperation indications, decision algorithm for reoperation type, timing and graft material. The validity and effectiveness of second or further reoperations are reviewed. The relation of limb salvage rate in femoro-popliteal reocclusions and both surgical and conservative management strategies is driven.

[Reconstructive surgery on the femoro-popliteal segment in combination with lumbar sympathectomy]. / Rekonstruktivnye operatsii na bedrenno-podkolennom segmente v sochetanii s poiasnichnoi simpatéktomiei.

Long-term results of 660 reconstructive surgeries on the arteries of the femoro-popliteal segment performed from 1975 to 2002 are analyzed. Two hundred and twenty-eight (34.5%) of them were combined with lumbar sympathectomy (LSE) on the affected side. It was demonstrated that LSE influences outcomes of reconstructions on the femoro-popliteal segment. This influence depends on a primary degree of leg ischemia. At the stage of intermittent claudication LSE permits to improve patency of the femoro-popliteal segment, salvage of the leg, to decrease the rate of postoperative complications due to reduction of thrombosis and purulation rates. The rate of cardiovascular complications increases. In critical limb ischemia effect of LSE is opposite. It increases the rate of repeated occlusions and amputations compared with reconstructive surgeries without LSE. The rate of postoperative complications also increased due to thrombosis and cardiovascular complications. It is concluded that LSE is the factor improving outcomes of reconstructive surgery on the femoro-popliteal segment, but it must be used differentially. It is necessary to perform LSE during all reconstructive surgeries in patients with intermittent claudication and without serious cardiovascular diseases. In critical limb ischemia and serious concomitant cardiovascular diseases LSE must be avoided.

[Influence of the dismissed prisoners with pulmonary tuberculosis on the contingents of tuberculosis dispensaries]. / Vliianie bol'nykh tuberkulezom legkikh, osvobodivshikhsia iz mest lisheniia svobody, na kontingenty protivotuberkuleznykh dispanserov.

Individuals become annually free from confinement places, among them 10.3-28.6% are ill with pulmonary tuberculosis. An average of only 35.6% of this contingent are registered at dispensaries in the territories. Their mortality rates within the first year of registration are 2.3 times higher than those registered at dispensaries of these territories. The authors show it necessary to accomplish cooperation between the health care facilities of the Ministry of Health of Russia and those of the Ministry of Justice of Russia.

[The prevalence of hepatitis B and C markers among narcotic users]. / Rasprostranennost' markerov gepatitov B i C sredi potrebitelei narkotikov.

611 patients with acute parenteral virus hepatitis (VH) were studied with a view to find out markers indicating the presence of hepatitis B and hepatitis C virus infection (HB, HC, HB + C, HC + HBsAg). Of these, 166 patients (27.2%) systematically used narcotic drugs intravenously. Essential differences between drug users and VH patients without drug addiction were established regarding the distribution of patients by age and sex, the etiological structure and severity of the disease. Thus, in the group of drug users the prevalence of males, young people (15-29 years of age) and the mixed form of hepatitis B + C was noted. In VH patients using drug the disease took a more severe course than in such patients without drug addiction. The highest proportion of intravenously drug users with a severe and moderate course of the disease was found among patients with HB + C and HB.

[The immune response of viral hepatitis patients who use narcotic preparations]. / Immunnyi otvet u bol'nykh virusnymi gepatitasmi--potrebitelei narkoticheskikh preparatov.

The characteristics of cell-mediated and humoral immunity were studied in 611 patients with different etiological forms of acute virus hepatitides (HB, HC, HB + C, HC + HBsAg). As the result of the systematic abuse of psychoactive preparations, introduced by intravenous injection, in 166 patients (27.2%) drug addiction developed, ehile 445 (72.8%) patients had no addiction. The study revealed that in drug users with HB the secondary T-cell immunodeficiency of the hyposuppressor type in combination with depression in B-cell-mediated immunity (a decrease in the absolute number of B lymphocytes) could be registered, and in patients having no drug addiction the secondary T-cell immunodeficiency characterized by a decrease in the content of T helpers simultaneously with the increased content of T suppressors and B lymphocytes.

Hygienic classification of pesticides in the Russian Federation.

Hygienic classifications of pesticides used in the Russian Federation are presented. The classifications cover both technical products and preparative forms of pesticides. Four classes of hazards are distinguished: extremely hazardous, hazardous, moderately hazardous, and slightly hazardous. These four classes are used for classifying general toxicity (peroral, skin, inhalation), cumulative, allergic, teratogenic, embryotoxic, reproductive, mutagenic, carcinogenic effects, and the stability in soil. The class of the hazard is determined on the basis of toxicohygienic evaluation of a pesticide, taking into account a limiting criterion of the hazard.

[Changes in the hemostatic system after administration of the mycotoxin deoxynivalenol (vomitoxin) to rhesus monkeys]. / Izmeneniia v sisteme gemostaza pri vvedenii mikotoksina-- dezoksinivalenola (vomitoksina) obez'ianam makakam rezusam.

The toxic effect of deoxynivalenol was studied in experiments on 8 test and 3 control Macaca rhesus monkeys. It has been found that differences in the hemostasis parameters depend on the frequency of deoxynivalenol administration. Normalization of the blood coagulation process is recorded after 1.5-2 months. Early diagnosis of intoxication with mycotoxins, deoxynivalenol in particular, is of great prognostic significance and may help prevent the development of irreversible changes in the body.