[en] An unattended video surveillance unit, the Modular Integrated Video System (MIVS), has been developed by Sandia National Laboratories for International Safeguards use. An important support element of this system is a semi-automatic Review Station. Four component modules, including an 8 mm video tape recorder, a 4-inch video monitor, a power supply and control electronics utilizing a liquid crystal display (LCD) are mounted in a suitcase for probability. The unit communicates through the interactive, menu-driven LCD and may be operated on facility power through the world. During surveillance, the MIVS records video information at specified time intervals, while also inserting consecutive scene numbers and tamper event information. Using either of two available modes of operation, the Review Station reads the inserted information and counts the number of missed scenes and/or tamper events encountered on the tapes, and reports this to the user on the LCD. At the end of a review session, the system will summarize the results of the review, stop the recorder, and advise the user of the completion of the review. In addition, the Review Station will check for any video loss on the tape

[en] Membrane proteins from alkalophilic Bacillus firmus RAB were extracted with octylglucoside, reconstituted into liposomes made from alkalophile lipids. The proteoliposomes were loaded with ²²Na⁺. Imposition of a valinomycin-mediated potassium diffusion potential, positive out, resulted in very rapid efflux of radioactive Na⁺ against its electrochemical gradient. That the Na⁺ efflux was mediated by the electrogenic Na⁺/H⁺ antiporter is indicated by the following characteristics that had been established for the porter in previous studies: dependence upon an electrical potential; pH sensitivity, with activity dependent upon an alkaline pH; inhibition by Li⁺; and an apparent concentration dependence upon Na⁺ that correlated well with measurements in cells and membrane vesicles

[en] Bepridil, an antiarrhythmic agent, inhibits Na-Ca exchange in cardiac sarcolemmal membrane vesicles by a novel mechanism, different from that determined for amiloride analogues. Bepridil causes partial inhibition of Na/sub o/-dependent ⁴⁵Ca²⁺ efflux. Inhibition of Na-Ca exchange is noncompetitive vs Ca²⁺ but competitive vs Na⁺ in both K⁺ and sucrose. Bepridil also blocks Ca-Ca exchange, with or without K⁺ present. However, K⁺ has two effects on inhibition: it reduces the potency of bepridil and causes inhibition to become partial. Inhibition of Ca-Ca exchange displays noncompetitive kinetics vs Ca²⁺ in either sucrose of K⁺. Dixon analyses of Na-Ca exchange inhibition caused by mixtures of bepridil and amiloride analogues demonstrate that these compounds produce a competitive interaction at a common carrier site that is evident only a low concentrations of amiloride inhibitors. Hill plots of bepridil inhibition of Na-Ca and Ca-Ca exchange display unitary Hill coefficients. These results indicate that bepridil interacts at only one substrate-binding site, the site selective for Na⁺, where amiloride analogues also preferentially interact. However, unlike amiloride, bepridil does not interact at the common Na⁺, Ca²⁺-binding site of the carrier. During stimulation of Ca-Ca exchange, K⁺ may bind at other sites besides the site selective for Na⁺, because in addition to being competitive with bepridil, it prevents complete abolition of Ca-Ca exchange, suggesting that this Na⁺ site is not involved in carrier turnover. These findings indicate the bepridil is a mechanisms-based Na-Ca exchange inhibitor that interacts at a transporter site which binds Na⁺ but not Ca²⁺

[en] The mechanism by which terminal guanidino nitrogen substituted analogues of amiloride inhibit Na-Ca exchange in purified cardiac sarcolemmal membrane vesicles has been investigated. These inhibitors block both Na/sub i/-dependent Ca²⁺ uptake and Na₀-dependent Ca²⁺ efflux. Inhibition of Na-Ca exchange monitored in K⁺ is noncompetitive vs ⁴⁵Ca²⁺ but competitive vs ²²Na⁺. Substitution of sucrose for K⁺ results in mixed kinetics of inhibition vs ⁴⁵Ca²⁺, suggesting a complex interaction between inhibitor and carrier under this condition. Amiloride derivatives also block two other modes of carrier action: Na-Na exchange is inhibited in a competitive fashion with Na⁺ and kinetics of Ca-Ca exchange inhibition are mixed vs Ca²⁺ in either sucrose or K⁺. However, Ca-Ca exchange inhibition can be alleviated by increasing K⁺ concentration. Dixon analyses of Na-Ca exchange block with mixtures of inhibitors suggest that these agents are interacting at more than one site. In addition, Hill plots of inhibition are biphasic with Hill coefficients of 1 and 2 at low and high inhibitor concentration, respectively. These results indicate that amiloride derivatives are mechanisms-based inhibitors that interact at two classes of substrate-binding sites on the carrier; at low concentration they bind preferentially to a site that is exclusive for Na⁺, while at higher concentration they also interact at a site that is common for Na⁺, Ca²⁺, and K⁺

No abstract available

[en] In this work the evaluation of the concentration of ²²² Rn in air for Zacatecas is shown. The Solid State Nuclear Track Detectors were used as the technique for the realization of the measurements in large scale with cellulose nitrate LR-115, type 2, in open chambers of ²²² Rn. The measurements were carried out during three months in different times of the year. In the results it is presented the log normal distribution, arithmetic mean and geometric media for the concentration at indoor and outdoor of residence constructions, the concentration at indoor of occupational constructions and in the 57 municipal heads of the state of Zacatecas. The statistics of the values in the concentration showed variation according to the time of the year, obtaining high quantities in winter seasons for both cases. The distribution of the concentration of ²²² Rn is presented in the state map for each one of the municipalities, representing the measurement places in the entire state of Zacatecas. Finally the places where the values in the concentration of ²²² Rn in air are near to the one limit settled down by the EPA of 148 Bq/m³ are presented. (Author)

[en] Since the SSNTD technique (Solid State Nuclear Track Detection) it was discovered it has been used as passive method for the detection of subnuclear particles in great variety of fields of the science. The use of the technique in measurements of ²²² Rn in air have already been established implying better methodologies in the exhibition to the environment until their engraving and reading processes. The SSNTD technique is since a method by comparison since the material it can be used a single time, therefore it requires of calibration in one controlled radon atmosphere, using gauged standards. The objective of this work is to show the calibration of the devices used as radon monitors based on SSNTD. The material used as SSNTD is LR-115 Il. The standardization of the parameters used in the exhibition to radon in air, engraving and reading process, its are based on the response of the LR-115 Il, the one arrangement of the device, engraving speed and mainly the calibration factor. They are considered two types of monitors: Open camera and Closed camera, the difference among the calibration factors of both cameras is the percentage of the descendants of radon in the open camera. The standardized parameters are operation voltage of the counting system; temperature, time and concentration of the engraving solution; and thickness. (Author)

[en] The semi-automatic counting system based on electric spark and used for traces reading in solid state detectors is evaluated for obtaining its counting voltage and also the breaking voltage of material. In the treatment of the solid state detectors it is continued the NTD methodology for concluding with the individual counting of the films, whose graphics offer the existing relationship among the applied voltage and the traces number. From each film a counting and breaking voltages are obtained. Finally, an average voltage of all them is estimated. (Author)

[en] A study of detection of environmental radiation in the inner of an office is presented and a comparison of the results is made when the facilities are closed or aired. The used method is based on radiation detection by means of Geiger-Mueller RM 60 and RM 70 detectors with the aid of a personal computer which provides a detection method of radiation in real time. The used method in this study is suggested to detect the variation of radiation in closed or aired environments and as a surveillance system of radiation levels. The obtained results are discussed and they are compared with those obtained in another places. (Author)

[en] Indoor radon gas (²²²Rn), present in the air inside buildings, is one of the most important sources of radiation exposure to the population. This gas originates in the ²³⁸U radioactive decay chain, which is contained in rock and solid soil particles. Radon accumulation in confined spaces, inside buildings, depends on several factors such as the type of soils, type of constructions, building materials, and ventilation. The aim of this work is to present indoor and outdoor radon concentrations for 202 dwellings and indoor concentrations for 148 public clinics; and the radon concentrations relate to the type of predominant soils, the construction years; and building materials used in the ceilings, walls and floors, for cities and towns of the 57 municipalities in the State of Zacatecas, Mexico. The ²²²Rn concentrations were measured with a passive-type radon monitor, with LR-115 as detector material; and the radon survey was made during four stages of three months each throughout Zacatecas from 2001 to 2002. The indoor and outdoor radon concentration averages in dwellings were 55.6±4.9Bqm^-3 and 46.5±5.3Bqm^-3, respectively. The indoor radon concentration average in public clinics was 57.8±5.4Bqm^-3. These values were lower than the US EPA action limit of 148Bqm^-3