Energy Technology Data Exchange (ETDEWEB)

The effective half-life based on urine bioassay results of Wolsung NPP's worker was calculated. The effective half-life for tritiated water vapour obtained was 5 {approx} 9 days. In comparison to 10 days reported for ICRP-30, it is lower than the corresponding half-life for Reference Man. Also, the half-life was calculated based on intake amount of daily water. According to this result, the metabolism was reviewed.

International Nuclear Information System (INIS)

... electrophoresis fission products gamma radiation gamma spectra half-life

International Nuclear Information System (INIS)

... coincidence spectrometry decay excited states gamma spectra half-life

International Nuclear Information System (INIS)

... charges energy levels gamma spectra half-life isomeric nuclei kev range

International Nuclear Information System (INIS)

... coriolis force de-excitation excited states half-life iridium 187 multipolarity

Energy Technology Data Exchange (ETDEWEB)

The diagnosis of idiopathic pulmonary hemosiderosis (IPH) may be elusive. A 6-year-old boy had microcytic hypochromic anemia and a hemolytic component. Hemosiderin-laden macrophages were not found in the gastric aspirate. He had no pulmonary signs or symptoms. Extensive hematologic and roentgenologic investigations failed to reveal the cause of the anemia. Quantitative serial scintigraphic scanning showed significant (35%) pulmonary sequestration of autologous erythrocytes labeled with sodium chromate Cr51. The half-life of the RBCs was moderately decreased (half-life, 15 days; normal, 25 to 35 days). An open-lung biopsy spece Cr51. The half-life of the RBCs was moderately decreased (half-life, 15 days; normal, 25 to 35 days). An open-lung biopsy specimen confirmed the diagnosis of IPH. A diagnosis of IPH should be considered when children have iron deficiency anemia and pulmonary signs or symptoms. ...

Science.gov (United States)

The total half-life and the half-life for spontaneous fission are evaluated for the various long-lived nuclides of interest. Recommended values are presented for /sup 241/Am, /sup 242m/Am, /sup 243/Am, /sup 242/Cm, /sup 243/Cm, /sup 244/Cm, /sup 245/Cm, /sup 246/Cm, /sup 247/Cm, /sup 248/Cm, and /sup 250/Cm. The uncertainties are provided at the 95% confidence limit for each of the recommended values.

Energy Technology Data Exchange (ETDEWEB)

Measurements of the half-lives of some long-lived nuclides of elements Z = 92, 94, 95 and 96 have been compiled and evaluated. Recommended values are presented for {sup 232-236,238}U, for {sup 236,238-242,244}Pu, for {sup 241,242m,243}Am, and for {sup 242-248,250}Cm. Values are presented for both spontaneous fission half-life and total half-life. Problems with reported uncertainties are also discussed. (author).

Energy Technology Data Exchange (ETDEWEB)

The nuclei {sup 81}Zr and {sup 85}Mo with T{sub z}=1/2 have been reinvestigated via their {beta}-delayed proton emissions with p-{gamma} coincidence measurement. The half-life of {sup 81}Zr has been measured to be 5.3{+-}0.5 s, which agrees with one of the two previous values. For {sup 85}Mo, the measured half-life is 3.2{+-}0.2 s, which revises the previous value. (orig.) With 3 figs., 12 refs.

International Nuclear Information System (INIS)

75 mg (NH_4)_6Mo_7O_24 #centre dot# 4H_2O solution was irradiated for 20 min in miniature neutron source reactor (MNSR) and cooled for 12 min. In the conditions of 0.8 mol/L HNO_3, phase ratio 1:1, the solution of "1"0"1Tc sample was extracted twice with #alpha#-benzoin oxime/ethyl acetate phase to remove "1"0"1Mo and a radiochemically pure and carrier-free "1"0"1Tc product was obtained. The half-life of "1"0"1Tc was accurately measured with a HPGe #gamma#-detector by following 306.8 keV #gamma#-ray about 150 min, and processed the data by three methods, R-value method, iterative method and translation method. Five parallel measurments gave a half-life (14.02 #+-# 0.01) min (n=5) for "1"0"1Tc. (authors)

International Nuclear Information System (INIS)

No-carrier-added astatine radionuclides produced in the "7Li-irradiated lead matrix were separated from bulk lead nitrate target by complexing At with insulin, followed by dialysis. The method offers simultaneous separation of At from lead as well as its complexation with insulin. The At-insulin complex might be a potential radiopharmaceutical in the treatment of hepatocellular carcinoma. The stability of At-insulin complex was checked by dialysis against deionized water and Ringer lactate (RL) solution. It has been found that the half-life of At-insulin complex is about #approx#12 h, when dialyzed against deionized water and is only 6 h, when dialyzed against RL solution having the same composition as blood serum. The 6 h half-life of this Insulin-At complex is perfect for killing cancer cells from external cell surfaces as the half-life of internalization of insulin molecule inside the cell is 7-12 h.

Science.gov (United States)

The long-lived nuclides of the americium curium elements are of interest for their use in certain safeguard applications and for nuclear reactor burnup studies in waste management. Recommended values are presented for /sup 241,242m,243/Am, and for /sup 242,243,244,245,246,247,248,250/Cm. These values result from a consistent evaluation of all these half-lives. These preliminary estimates were presented earlier. The uncertainties are provided at the 95% confidence limit for each of the recommended values. It will be noted that many of the recommended errors considerably exceed errors quoted by individual authors in their publication, by up to an order of magnitude, e.g., the total half-life of /sup 242,246,248/Cm and the spontaneous fission half-life of /sup 244/Cm. 65 refs., 18 tabs.

Energy Technology Data Exchange (ETDEWEB)

A newly-available radioisotopic system, /sup 172/Hf-/sup 172/Lu, has excellent potential for tracer applications in which nuclear data acquisition must be accomplished in real time. The 6.7-day half-life of /sup 172/Lu is sufficient for a large fraction of tracer experiments, and should allow the direct incorporation of /sup 172/Lu into tests that have traditionally utilized much longer-lived radionuclides. Since /sup 172/Lu is the daughter component of a radioisotope generator, however, its effective shelf-life is determined by the half-life of its 1.9-year /sup 172/Hf parent. Consequently, the frequency of isotope procurement need not be any more extensive than investigators would normally be accustomed to. Discussion relevant to isotope production, generator operation, and nuclide acquisition is presented in this paper.

International Nuclear Information System (INIS)

In this work, the half-life of the "1"5"5Sm #beta#"- decay was determined using enriched "1"5"4Sm samples submitted to irradiation in the IEA-R1 reactor of IPEN; the activity of the samples were followed for 4-5 consecutive half lives using a 198 cm"3 HPGe detector. The data was corrected using a non paralizable dead time correction and fitted to an exponential decay function using a non linear fitting procedure developed on the MatLab platform. The resulting value--T_1_/_2 = 22.180(26) min--was compatible to the one found in the literature, with a lower uncertainty.

International Nuclear Information System (INIS)

The use of chemically selective laser ionization combined with beta-delayed neutron counting at ISOLDE has permitted identification and half-life measurements for "6"1Mn up through "6"9Mn. The 14(4)-ms half life for "6"9Mn is one of the shortest determined for any nuclide beyond the sd shell. Gamma-ray singles and coincidence spectra have been determined for the decays of "6"4","6"6Mn to levels of "6"4","6"6Fe, revealing strong deformation and vanishing of the N=40 subshell in the Fe isotopes.

Energy Technology Data Exchange (ETDEWEB)

An experimental plan for improving the problems of failed fuel location system in Wolsung Unit-2 reactors was established. It is not possible to make an experiment on the failed fuel monitoring nuclides in the cold laboratories because they have very short half life. Therefore, the experiments can be only carried out at the existing monitoring system under reactor operation. For that reason, an experimental plan was drawn up for installing the radiation detection system on reactor site.

Energy Technology Data Exchange (ETDEWEB)

Ex vivo (/sup 3/H)-8-hydroxy-2-(di-n-propylamino)-tetraline ((/sup 3/H)-DPAT) binding to the hippocampus has been utilized to determine the pharmacokinetic parameters of buspirone after i.v. and oral administration of this drug to rats. Intravenous buspirone rapidly penetrated the brain as demonstrated by a maximum inhibition of (/sup 3/H)-DPAT binding at 1 min. Elimination of drug from the brain was biphasic, with a first component half-life of 24.8 min and a second component half-life of 96 min. Oral buspirone at 3 times the i.v. dose produced less than one-third the maximum inhibition of (/sup 3/H)-DPAT binding compared to that observed with i.v. buspirone. The pharmacokinetic parameters of buspirone observed in the present study are in agreement with those reported previously. Thus, the ex vivo binding assay could be utilized to determine the bioavailability of the drug to the brain, and its duration of action. 20 references, 2 figures, 5 ...

Energy Technology Data Exchange (ETDEWEB)

Two series of diffusion tests were performed to examine the degradation of dichloromethane (DCM) as it diffuses through clay. The first series showed the use of a synthetic leachate with no significant initial bacterial population diffusing through a plug of intact clay; there was an induction period of 95--135 d, during which diffusion was as expected in the absence of degradation, followed by a second stage, where degradation occurred with an apparent half-life of less than 55 d at a temperature of 24 C. The second series of tests examined the diffusion of an actual leachate from the Keele Valley Landfill (KVL) (which provided both nutrients and a source of bacteria), through a compacted clay. In these tests, the induction period was reduced to 40--60 d, after which the apparent half-life was 20 d or less at 27 C. The diffusion coefficient for DCM was approximately 8 {times} 10{sup {minus}10} m{sup 2}/s, with partitioning coefficient K{sub d} ...

Energy Technology Data Exchange (ETDEWEB)

Procedures for {sup 131}I ablation in renal failure are not known. In one patient receiving dialysis, detailed dosimetry and health safety aspects were obtained. The results showed insignificant contamination of equipment, but a surprisingly significant reduction in biologic half-life of {sup 131}I due to efficient dialysis extraction. The data indicate that {sup 131}I ablation can be done safely and easily during dialysis but that much higher {sup 131}I doses must be used to achieve equivalent results to those obtained in patients with normal renal function.

Energy Technology Data Exchange (ETDEWEB)

The isomer /sup 242m/Am with a half-life of 141 yr. is obtained from a (n,..gamma..) capture reaction with /sup 241/Am. The latter is a decay product of /sup 241/Pu. The isomer /sup 242m/Am has the highest known thermal fission cross section. The cross sections of this isomer are evaluated. Unit cell calculations show that nuclear systems with /sup 242m/Am require less fuel by a factor of 2 to 100 compared to conventional fuels. These results indicate that potential applications of americium fuel exist, particularly for space reactors.

International Nuclear Information System (INIS)

In this work, the half-lives of the beta-unstable nuclei "1"0"1Mo and "1"0"1Tc were studied using neutron-irradiated samples of "1"0"0Mo to produce "1"0"1Mo which in its turn generates "1"0"1Tc by beta decay. The gamma activity of each sample was followed for 5 consecutive half-lives in steps of 5 minutes. A total of 22 sources were measured and checked for dead-time influence, and the half-lives were obtained by weighted average. The results are statistically incompatible with the tabulated values.

International Nuclear Information System (INIS)

Radiopharmaceuticals for brain imaging are used for the detection of ischemia, tumours and dementia associatied with disorders of the blood flow in the brain. The current radiopharmaceuticals for brain imaging have various limitations: 2-(F-18)fluoro-2-deoxyglucose (F-18-FDG) has a very short half-life. The physical properties of di-#beta#-(piperidinoethyl)-(Se-75)selenide (Se-75-PIPSE) and di-#beta#-(morpholinoethyl)-(Se-75)-selenide (Se-75-MOSE) are not ideal. Thallium-201 diethyldithricarbamate (T1-201-DDC) has unfavourable nuclidic characteristics, limited availability, a long half-life and high cost. I-123 in N-isopropyl-p-iodoamphetamine (I-123-IMP) and N,N,N'-trimethyl-N'-(2-hydroxy-3-methyl-5-iodobenzyl)-1,3-propanediamine (I-123-HIPDM) are not freely available and are expensive. N-13-labelled ammonia has a very short half-life. Technetium-99m hexamethylpropyleneamineoxime (Tc-99m-HM-PAO) is unstable both in vitro ...

Science.gov (United States)

A new method of administration of an opioid was recently registered: fentanyl transdermal (brand name: Durogesic), intended particularly for the indication range 'pain in cancer'. Fentanyl is lipid-soluble so that deposition in the skin takes place and the biological half-life is approximately 20 hours after removal of the plaster. It is safe to start on a basis of an equianalgesic conversion of 100:1 in relation to oral morphine, although this may entail some risk of fentanyl under dosage. The dose adjustment time is 12-24 hours before a constant fentanyl level is reached; therefore, after attaching the first sticking plaster, the original morphine dose should be continued for another 12 hours. In addition, the patient may, if necessary, be given supplementary morphine preferably as a short-acting drug. There seems to be no clear indication for transdermal fentanyl either in neuropathic pain or in chronic benign pain. PMID:9221362

British Library Electronic Table of Contents (United Kingdom)

Tert-Butanol is an important intermediate in industrial chemical synthesis, particularly of fuel oxygenates. Human exposure to tert-butanol may occur following fuel oxygenate metabolism or biodegradation. It is poorly absorbed through skin, but is rapidly absorbed upon inhalation or ingestion and distributed to tissues throughout the body. Elimination from blood is slower and the half-life increases with dose. It is largely metabolised by oxidation via 2-methyl-1,2-propanediol to 2-hydroxyisobutyrate, the dominant urinary metabolites. Conjugations also occur and acetone may be found in urine at high doses. The single-dose systemic toxicity of tert-butanol is low, but it is irritant to skin and eyes; high oral doses produce ataxia and hypoactivity and repeated exposure can induce dependence...

International Nuclear Information System (INIS)

A brief survey is presented of the methods of preparation and of the applications of radiopharmaceuticals labelled with short-lived positron radionuclides "1"1C, "1"8F, "1"3N and "1"5O which, thanks to their energy level schemes, short half-life and the 511 keV photon radiation energy are almost ideal tracers in modern nuclear medicine and pharmacology. In conjunction with computerized tomography, they represent one of the most sensitive diagnostic imaging methods, the so-called positron emission tomography. In addition, their incorporation in the molecule of a pharmaceutical does not change the biological and chemical properties of the original molecule unlike those of radiopharmaceuticals labelled with technetium, iodine, etc. (author). 125 refs.

Energy Technology Data Exchange (ETDEWEB)

We have investigated via SQUID magnetometry and polarised neutron reflectivity the exchange-bias effect in CoO/Co sputtered multilayers. In particular, we studied the magnetisation reversal and the time relaxation of the exchange-bias field close to the coercive field H{sub c1}. Neutron intensities of all four cross sections (I++, I+-, I-+, I-) were recorded at the position of the first multilayer Bragg peak while scanning the magnetic field. From such scans we infer that the magnetisation reversal for the ascending as well as for the descending branch of the magnetic hysteresis occurs not by in-plane rotation but through domain-wall movements. The exchange-bias field, H{sub EB}, is strongly affected by thermal fluctuations. H{sub EB} decreases, following an exponential decay function with a half-life time of about 580 s at T=240 K. (orig.)

International Nuclear Information System (INIS)

Pulse radiolysis was used to examine the nature of the silver species obtained when an aqueous solution containing sequestered Ag"+ ions was reduced by hydrated electrons in the presence of a surfactant macrocyclic crown ether, labeled L, and/or a maltoside surfactant. The initially formed product is the Ag"0(L) species which rapidly loses its ligand (half-life #<=#5 #mu#s) and reacts with another Ag"+(L) ion to form Ag_2"+(L). The latter species decays by a bimolecular process to form the Ag_4"2"+(L)_n species at a faster rate than its ligand free analogue. Ultimately, colloidal metallic silver, (Ag)_n, forms which is stabilized by the surfactant moieties. No long-term stability to the reduced monomolecular species could be obtained.

Energy Technology Data Exchange (ETDEWEB)

A female employee was exposed to lead dust for 8 h daily from 4.5.1982 to 20.5.1982. During this time conception occurred (1st day of last menses 4.5.82). Acute symptoms of lead intoxication were not observed in this subject but were in other employees. Measurements of lead content were started after the end of exposure and continued for 6 months until normal values were obtained. Because of the half-life of nearly 20 days for lead elimination from blood the estimated body burden at the end of exposure was about 1200 ppb. The fetal tissue samples contained between 0.4 (brain) and 7.9 (liver) ..mu..g lead/g dry weight. The fetal lead was mainly stored in bone, blood and liver. From the results given a delayed elimination of fetal lead is suggested.

Science.gov (United States)

Selenium 79 is a beta emitter produced from (235)U fission and is one of the long half-life radionuclides of interest in nuclear waste disposal problematic because of its potential migration capacity to the surface environment. Measurement of (79)Se is particularly difficult due to its low activity in waste matrices (about 10(-3)Bqg(-1)). A radiochemical procedure based on ion exchange separations was already described in a previous paper. This work presents different applications of the radiochemical separation to waste samples and an improvement of this procedure, including a selective extraction of selenium as diethylselenium in an organic solvent followed by a re-extraction in aqueous medium. This additional step allows the decontamination factor to be increased with the aim of counting (79)Se by liquid scintillation counting. PMID:19071740

International Nuclear Information System (INIS)

The use of chemically selective laser ionization combined with #beta# -delayed neutron counting at CERN/ISOLDE has permitted identification and half-life measurements for 623-ms "6"1Mn up through 14-ms "6"9Mn . The measured half-lives are found to be significantly longer near N=40 than the values calculated with a quasiparticle random-phase-approximation shell model. Gamma-ray singles and coincidence spectroscopy has been performed for "6"4","6"6Mn decays to levels of "6"4","6"6Fe , revealing a significant drop in the energy of the first 2"+ state in these nuclides that suggests an unanticipated increase in collectivity near N=40 . copyright 1999 The American Physical Society.

International Nuclear Information System (INIS)

A review is presented of the literature through 1977 on the uses of radioactive lead isotopes in metabolic studies in man, animals, and plants. These studies have been done mainly with the naturally-occurring, long-lived (22-yr half life) "2"1"0Pb, but a few were with 53-hr "2"0"3Pb or 10.6-hr "2"1"2Pb. Such studies have made possible estimates of the metabolic parameters of lead in man and animals, such as intestinal absorption, the ratio of fecal-to-urinary excretion of endogenous lead, residence time of lead in the body and in various organs, and the distribution in the body (skeleton, liver, kidney, and blood). Subsequently, these parameters and data have been used to trace the sources of lead for man, such as those from the atmosphere, food, cigarette smoke, and automobile exhaust.

Energy Technology Data Exchange (ETDEWEB)

Recently, the precise isotope ratios of some refractory elements in meteorites have been reported using inductively coupled plasma mass spectrometry. The in situ decay of {sup 182}Hf (T{sub 1/2}=9 Myr), which was produced at the latest nucleosynthesis, is recognized in many meteorites as isotopic anomalies of its daughter isotope, {sup 182}W. The degrees of relative {sup 182}W isotopic deviation in extra-terrestrial and terrestrial silicate samples vary from +0.3% to {+-}0% related to the size of their parent bodies. One ready interpretation of its correlation is the difference in timing of metal-silicate separation in the parent bodies. Between the earth and meteorite parent bodies, the difference is calculated to be about four times of the half-life of {sup 182}Hf, equivalent to 36 Myr. (author)

Science.gov (United States)

Glucoamylase and pullulanase were immobilized on reconstituted bovine-hide collagen membranes using the covalent azide linkage method. A pretanning step was incorporated into the immobilization procedure to enable the support matrix to resist proteolytic activity while accommodating an operating temperature of 50 degrees C. The immobilized glucoamylase and pullulanase activities were 0.91 and 0.022 mg dextrose equivalent (DE) min(-1) cm(-2) of membrane, respectively. Immobilized glucoamylase had a half-life of 50 days while the immobilized pullulanase had a half-life of 7 days. This is a considerably improved stability over that reported by other researchers. The enzymes were studied in their free and immobilized forms on a variety of starch substrates including waxy maize, a material which contains 80% alpha-1-6-glucosidic linkages. Substrate concentrations ranged from 1% to a typical commercial concentration of 30%. Conversion efficiencies of ...

Energy Technology Data Exchange (ETDEWEB)

Hyaluronan is an important constituent of the extracellular matrix in skin, and recent studies suggest that there is a pool of easily removable (free) hyaluronan drained by lymph. The removal rate of free hyaluronan in skin was measured from the elimination of ({sup 3}H)hyaluronan, injected subcutaneously in 13 rabbits. The removal of radioactivity was determined from appearance of {sup 3}H in plasma. During the first 24 h after injection, 10-87% of the tracer entered blood, less in injectates with high concentrations of hyaluronan. The removal was monoexponential with a half-life of 0.5-1 day when concentration of hyaluronan was 5 mg/ml or less. When hyaluronan concentration was 10 mg/ml or higher, the removal was slow for about 24 h and then became similar to that in experiments with low hyaluronan concentration. Free hyaluronan at physiological concentrations is thus turned over with the same rate as serum albumin, supporting the concept that hyaluronan is ...

Energy Technology Data Exchange (ETDEWEB)

The radioiodine-labeled amines currently available as brain-imaging agents, based on our previous work and that of others, are prepared either by exchange labeling or by direct iodination of a protected intermediate. The intrinsic slowness of these processes limits their potential for use with the positron-emitting 122I, as it has a half-life of only 3.6 min. This isotope has advantages of a low dose to the patient and availability from a generator containing the parent 20-h 122Xe. To develop a radiopharmaceutical in which 122I could be utilized, we prepared a number of secondary and tertiary amines (maintaining the 2,5-dimethoxy substitution pattern which allows direct iodination at the 4-position) with 131I. The organ distributions of these compounds were studied, and the best properties were found in the N,N-dimethyl homologue (2,5-dimethoxy-N,N-dimethyl-4-iodoamphetamine). This compound was successfully synthesized in a matter of seconds, with a chemical yield ...

Energy Technology Data Exchange (ETDEWEB)

RADIANT{trademark} is manufactured by United States Surgical Corporation, Vascular Therapies Division, (formerly Progressive Angioplasty Systems). The system comprises a liquid {beta}-radiation source, a shielded isolation/transfer device (ISAT), modified over-the-wire or rapid exchange delivery balloons, and accessory kits. The liquid {beta}-source is Rhenium-188 in the form of sodium perrhenate (NaReO{sub 4}), Rhenium-188 is primarily a {beta}-emitter with a physical half-life of 17.0 hours. The maximum energy of the {beta}-particles is 2.1 MeV. The source is produced daily in the nuclear pharmacy hot lab by eluting a Tungsten-188/Rhenium-188 generator manufactured by Oak Ridge National Laboratory (ORNL). Using anion exchange columns and Millipore filters the effluent is concentrated to approximately 100 mCi/ml, calibrated, and loaded into the (ISAT) which is subsequently transported to the cardiac catheterization laboratory. The delivery catheters are modified ...

International Nuclear Information System (INIS)

Ozone production by synchrotron radiation as a function of power density in air was investigated using a white beam at the BNL National Synchrotron Light Source (NSLS) x-ray ring. Power densities were calculated from the energy spectrum at 2.52 GeV. Ozone concentrations in small beam pipes were measured for power densities between I = 10/sup 12/ and 10/sup 15/ eV/sup . /cm/sup -3 . /sec/sup -1/. The measured ozone half-life was 37+-2 min. The measured G-value was 2.69+-0.14 mol/100 eV and the ozone destruction factor k was less than 5 x 10/sup -19/cm/sup 3//eV. The random uncertainties stated are approximately one standard error. The large departure of the values for G and k from previous values suggest that some undiscovered systematic error may exist in the experiment. Ozone concentration in excess of the 0.1 ppm ACGIH TLV can be generated in the experimental hutches but can readily be controlled. Industrial hygiene aspects of operation and possible control ...

International Nuclear Information System (INIS)

64Cu (T1/2=12.7h, ?- decay: 40%, ?+ decay: 19%, E.C. decay: 41%) is one of the most useful radioisotope in the nuclear medicine due to its multiple decay mode and the intermediate half-life. Several nuclear reaction, i.e., 64Ni(p,n)64Cu, 68Zn(p,?n)64Cu and 64Ni(d,2n)64Cu have been investigated for production. The highest could be obtained with proton irradiation on the enriched 64Ni target. For mass and routine production, the 64Ni target fabrication using electroplating, the reliable chemical separation of 64Cu from the irradiated 64Ni target and the effective recovery process for the recycling of very expensive enriched material ($20,000/g) and so forth are absolutely necessary to be established. In this work, we report our mass production method of 64Cu with 64Ni and Cyclone-30 accelerator

International Nuclear Information System (INIS)

Microsecond pulse radiolysis of oxygenated aqueous solutions containing 0.02 mol dm"-"3 sodium formate and 2 mmol dm"-"3 phosphate buffer at pH 7 was used to generate superoxide anion radicals. The influence of some biologically important compounds upon the rate of O_2"."-"b"a"r decay as monitored spectrophotometrically in the range of 245-300 nm. Hematoporphyrin (HP), hemin C (HC), catalase (Cat), cobalt sulfophthalocyanine (CoTSPc) were studied. Among the investigated compounds only Cat was found to show a high catalytic efficiency towards the self-decay of O_2"."-"b"a"r. A red shift of 0_2"."-"b"a"r absorption band and slowing down of its decay were observed to take place by adding HP or CoTSPc to the solutions containing formate ions in excess. This effect is associated with the formation of a transient superoxo-complex. An appearance of an intermediate species with absorption maxima at 350 nm and half-life of about 2 s was observed to accompany the ...

International Nuclear Information System (INIS)

Population distribution, atmospheric change, X/Q, characteristics of terrestrial ecosystem around Seoul site were surveyed. Environmental radiation and radioactivities such as gross#alpha#, gross#beta#, Cs-137, Sr-90 and H-3 of various environmental samples were analyzed. The values of environmental radiation dose tended to increase gradually in the light of the recent five years' results of environmental radiation monitoring around the nuclear power plants from 1980 to 1984, however, the changes were not significant. In addition, continuous assessment of environmental radiation monitoring on the roofs of main building and life science building at KAERI showed that the environmental radiation dose tended to increase a little during the night time. Judging from the above results, it is concluded that environmental contamination level by radioactive materials could be ignored in the case of radioisotope production or experiment using radioisotopes except the release of gaseous ...

International Nuclear Information System (INIS)

The feasibility of developing a fusion power monitor based on a fluid activation detector is considered here. The activation fluid may be either a liquid or a gas and its composition can be selected from a number of candidate materials to provide desired activation and decay characterisitcs. Performance calculations indicate that ordinary water would be a nearly ideal activation fluid. The "1"6O(n,p)"1"6N reaction has a threshold at about 10 MeV and a cross section energy dependence giving it a predominant response for unmoderated D-T fusion neutrons. Adequate activation can be obtained at moderate flow rates for remote counting away from the high radiation area of the reactor. The 7.16 sec half-life of "1"6N is ideal for remote counting with subsequent decay in a small hold-up tank to eliminate activity build-up in the recycled water.

Energy Technology Data Exchange (ETDEWEB)

Biocatalytic Desulfurization (BDS) represents an alternative approach to the reduction of sulfur in fossil fuels. The objective is to use bacteria to selectively remove sulfur from petroleum and middle distillate fractions, without the concomitant release of carbon. Recently, bacteria have been developed which have the ability to desulfurize dibenzothiophene (DBT) and other organosulfur molecules. These bacteria are being developed for use in a biocatalyst-based desulfurization process. Analysis of preliminary conceptual engineering designs has shown that this process has the potential to complement conventional technology as a method to temper the sulfur levels in crude oil, or remove the recalcitrant sulfur in middle distillates to achieve the deep desulfurization mandated by State and Federal regulations. This paper describes the results of initial feasibility studies, sensitivity analyses and conceptual design work. Feasibility studies with various crude oils and middle distillates ...

International Nuclear Information System (INIS)

A pyrochemical process has been introduced and utilized so that the transmutation of spent PWR fuel in PEACER can produce mainly low and intermediate level waste for near surface disposal. Major radioactive nuclides from PEACER pyro-processing are composed of TRU and LLFP. In this study, the requirement for the final waste from PEACER is evaluated based on the methodology for establishment of waste acceptance criteria. Also, sensitivity analysis for several input parameters is conducted in order to determine acceptable decontamination factor (DF) and LLFP removal efficiency and to find out input parameter that extremely have an effect on DF. As a result of the study, LLFP removal efficiency, especially Sr-90 and Tc-99, is proved to be a major nuclide which contributes to annual dose by human intrusion scenario rather than TRU DF. More than 98.5% of LLFP have to be removed to meet below dose constraint within the DF more than 5.0E+03. Besides, because of the relative short ...

International Nuclear Information System (INIS)

A pyrochemical process has been introduced and utilized so that the transmutation of spent PWR fuel in PEACER can produce mainly low and intermediate level waste for near surface disposal. Major radioactive nuclides from PEACER pyroprocessing are composed of TRU and LLFP. In this study, the requirement for the final waste from PEACER is evaluated based on the methodology for establishment of waste acceptance criteria. Also, sensitivity analysis for several input parameters is conducted in order to determine acceptable decontamination factor (DF) and LLFP removal efficiency and to find out input parameter that extremely have an effect on DF. As a result of the study, LLFP removal efficiency, especially Sr-90 and Tc-99, is proved to be a major nuclide which contributes to annual dose by human intrusion scenario rather than TRU DF. More than 98.5% of LLFP have to be removed to meet below dose constraint within the DF more than 5.0E + 03. Besides, because of the relative short ...

Science.gov (United States)

Using the phasmid vector pSL5, the genomic DNA fragment of T. aquaticus YT1 which contained the thermostable DNA polymerase (Taq-polymerase) gene was cloned. The BglII fragment of this genome locus was subcloned in the BamHI site of the pUC19 plasmid. To optimize the Taq-polymerase gene expression in E. coli cells, the gene was cloned in the correct reading frame regarding the initiation ATG codon of the pPR-TGATG-1 expression vector. The gene expression in this vector was controlled by the phage lambda PR promoter and the temperature-sensitive phage lambda repressor. We used PCR to amplify the short 5'-end fragment of the Taq-polymerase gene coding for the part into which an artificial SacI site was introduced. This site has been used for cloning the PCR product into the pPR-TGATG-1 vector, and the missing gene part was cloned into the KpnI site of the PCR product from the natural cloned gene. The cells of the E. coli PVG-A1 strain, which was obtained in the end, expressed efficiently ...

International Nuclear Information System (INIS)

An experimental investigation of the 70.5 keV #gamma#-ray transition from the 55/22"+[402] state to the 77/22"+[404] ground state in "1"7"7Ta was made. The half-life and magnetic moment of the initial state were found to be 73+-5 ns and 4.7+-0.5 #mu#sub(N) respectively. The E2/M1 mixing ratio of the transition was determined to be -0.10+-0.04. The reduced transition probabilities, B(E2) and B(M1), were found to be 2.9+-2.3e"2.fm"4 and (1.1+-0.1)x10"-"4#mu#sub(N)"2, respectively, and the M1 penetration parameter was determined to be 6+-2. The Coriolis mixing amplitude of the 75/22"+[402] state in the 77/22"+[404] ground state was determined from the B(E2) value to be -0.011+-0.004. It was found that the experimental value of the Coriolis matrix element <5/2"+/j-/7/2"+>sub(exp) was one-tenth of that calculated using the Nilsson wave function. The coefficient k_2, introduced by Wahlborn et al., was re-analyzed using the present experimental results and found to ...

Energy Technology Data Exchange (ETDEWEB)

An experimental investigation was made of the ..gamma..-transitions feeding or de-exciting the 1355 keV isomeric state in /sup 177/Ta. The E2/M1 mixing ratios for the 311 keV interband transition from the isomer and for the 271 keV and the 295 keV intraband transitions within the rotational band on the isomer were determined to be delta = 0.29sup(+0.11)sub(-0.06), 0.25sup(+0.05)sub(-0.03) and 0.30sup(+0.06)sub(-0.08), respectively, employing combined measurements of the linear polarization and angular distribution of the ..gamma..-ray with the aid of conversion electron measurements. Spin and parity assignments of the isomer were confirmed to be 21/2/sup -/. The half-life of the isomer was remeasured to be Tsub(1/2) = 5.0 +- 0.2 ..mu..s and the magnetic moment was found to be ..mu.. = 0.080 +- 0.014 ..mu..sub(N). The gsub(K) and gsub(R) factors for the band on the isomer were deduced separately to be gsub(K=21/2/sup -/) = 0.062sup(+0.011)sub(-0.008) and gsub(R) = ...

International Nuclear Information System (INIS)

Incorporation of tritium into body constituent molecules from tritiated water and its in vivo behaviors were studies using rats. In single administration of HTO, "3H behaviors were studied in lipids that are rich in hydrogen. Incorporation of "3H into the lipid fraction from HTO and its release differed by each organ and by the type of lipid components. Of routes of administration, the oral and parenteral routes showed same results, and no prominent difference was noted by inhalation. By consecutive administration, the urine "3H concentration showed no difference according to the route, but increased as the concentration of administered HTO increased. When administration was discontinued after the urine "3H concentration reached a plateau, the biological half-life was about 4.5 days, almost in agreement with the value by single administration. In relation to water intake, increase in the urine volume and accompanying promotion of urine "3H excretion in approximate ...

Science.gov (United States)

Vildagliptin is a potent and selective dipeptidyl peptidase IV inhibitor in development for the treatment of type 2 diabetes that improves glycemic control by enhancing alpha- and beta-cell responsiveness to glucose. Two open-label, single-dose, randomized, crossover studies in healthy subjects (ages 18-45 years) investigated the dose proportionality of vildagliptin pharmacokinetics (n = 20) and the effect of food (n = 24) on vildagliptin pharmacokinetics. There was a linear relationship (r(2) = 0.999) between vildagliptin doses of 25, 50, 100, and 200 mg and area under the plasma concentration-time curve from time zero to infinity (AUC(0-infinity)) and maximum plasma concentration (C(max)). Dose proportionality was assessed using a statistical power model [X = alpha x (dose)(beta)]. The 90% confidence intervals of the proportionality coefficient, beta, for AUC(0-infinity) (1.15-1.19) and C(max) (1.04-1.14) indicated that deviations from dose proportionality were small (<7.7%). ...

Science.gov (United States)

Designer natriuretic peptides (NPs) represent an active area of drug development. In canine and human studies, the designer natriuretic peptide CD-NP demonstrated more desirable therapeutic potential than recombinant B-type NP (BNP), which is known as nesiritide and is approved for treatment of acute decompensated heart failure. However, why CD-NP is more effective than BNP is not known. We previously reported that CD-NP is a poorer activator of human guanylyl cyclase-A (GC-A) and a better activator of human guanylyl cyclase-B than BNP. Here, guanylyl cyclase bioassays were used to compare the susceptibility of CD-NP verses ANP, BNP, CNP and DNP to inactivation by human kidney membranes. The half time (t(1/2)) for CD-NP inactivation was increased by factors of 13, 3 and 4 compared to ANP, BNP and CNP, respectively, when measured in the same assay. Surprisingly, DNP failed to undergo complete inactivation and was the most degradation resistant of the peptides tested. The neutral ...

Energy Technology Data Exchange (ETDEWEB)

The release of {sup 14}C as {sup 14}CO{sub 2} from partly failed spent fuel containers has been analyzed by the flow of gases into and out of the containers. This flow of gases is driven by pressure differences, which are in turn caused by heating by the spent fuel. In this analysis, the timing and size of holes in the containers are assumed to be given. A better means of predicting the time distribution and sizes of penetrations in nuclear waste containers is needed. For the purposes of far-field transport calculations, we have adopted release rates that are shown to be bonding for the large range of hole sizes studied. The transport of released {sup 14}CO{sub 2} has been analyzed by transport in equivalent porous medium. The peak {sup 14}CO{sub 2} concentration in pore gas at 350 m above the repository does not depend on the time of hole occurrence, although the time of penetration obviously affects the arrival and duration of exposure to {sup 14}C. Nor does water saturation have ...

International Nuclear Information System (INIS)

As an important radioisotope in nuclear industry and other fields, americium-241 is one of the most serious contamination concerns duo to its high radiation toxicity and long half-life. In this experiment, the biosorption of "2"4"1Am from solution by a fungus, Saccharomyces cerevisiae (S. cerevisiae), and the effects of various experimental conditions on the biosorption and the mechanism were explored. The preliminary results showed that S. cerevisiae is a very efficient biosorbent. An average of more than 99% of the total "2"4"1Am could be removed by S. cerevisiae of 2.1g/L (dry weight) from "2"4"1Am solutions of 2.22MBq/L -555 MBq/L (Co). The adsorption equilibrium was achieved within 1 hour and the optimum pH ranged 1-3. The culture times of more than 16 hours were suitable and the efficient adsorption of 241Am by the S. cerevisiae could be noted. The biosorption of 241Am by the decomposed cell wall, protoplasm or cell membrane of S. cerevisiae was same ...

Energy Technology Data Exchange (ETDEWEB)

Trichloroethene (TCE), a common groundwater contaminant, can be degraded under certain conditions by microorganisms that occur naturally in the subsurface. TCE can be degraded under anaerobic conditions to less chlorinated compounds and ultimately into the non-chlorinated, non-hazardous end product, ethene, via anaerobic reductive dechlorination (ARD). ARD is widely recognized as a TCE degradation mechanism, and occurs in active groundwater remediation and can occur during monitored natural attenuation (MNA). MNA relies on natural processes, such as dispersion and degradation, to reduce contaminant concentrations to acceptable levels without active human intervention other than monitoring. TCE can also be biodegraded under aerobic conditions via cometabolism, in which microbial enzymes produced for other purposes fortuitously also react with TCE. In cometabolism, TCE is oxidized directly to non-hazardous products. Cometabolism as a TCE-degrading process under aerobic conditions is less ...

Energy Technology Data Exchange (ETDEWEB)

This interim technical report presented a summary of results obtained from Pit Lake models developed from different simulation models. The models were used to predict stratification in a hypothetical Pit Lake. Predictions were used to assess the hydrodynamic similarities and differences between the 2 models and to determine if the models would produce similar stratification profiles for the Pit Lakes to previous models. Results showed that the models produced similar results for both temperatures and salinities. The main difference between the RMA10 and CE-QUAL-W2 model used in a previous study was found to be run time. A sensitivity analysis of the RMA10 and CE-QUAL-W2 model predictions was completed to assess the effects of segmentation; time step; lake surface area; lake orientation; and model coefficients or parameters. Results showed that the selected time step and model segmentation were appropriate, as both led to modelling results that were stable. However, while the CE-QUAL-W2 ...

Science.gov (United States)

Measurements using radioactive targets are important for the determination of key reaction path ways associated with the synthesis of the elements in nuclear astrophysics (sprocess), advanced fuel cycle initiative (transmutation of radioactive waste), and stockpile stewardship. High precision capture cross-section measurements are needed to interpret observations, predict elemental or isotopical ratios, and unobserved abundances. There are two new detector systems that are presently being commissioned at Los Alamos National Laboratory for very precise measurements of (n,{gamma}) and (n,f) cross-sections using small quantities of radioactive samples. DANCE (Detector for Advanced Neutron-Capture Experiments), a 4 {pi} gamma array made up of 160 BaF{sub 2} detectors, is designed to measure neutron capture cross-sections of unstable nuclei in the low-energy range (thermal to {approx}500 keV). The high granularity and high detection efficiency of DANCE, combined with the high TOF-neutron ...

Energy Technology Data Exchange (ETDEWEB)

{sup 14}C is a is a long-lived beta-emitting nuclide (T{sub 1/2} = 5730 years) produced naturally in the upper atmosphere as a result of reactions between neutrons and stable {sup 14}N({sup 14}N(n,p){sup 14}C). Although in a lesser extent, nuclear power plants produce {sup 14}C as well during their routine operation. Since it is converted in {sup 14}CO{sub 2} and mixed throughout the atmosphere, it is incorporated into plant tissues, via photosynthesis process, and hence in food chain. Because of the biological importance of {sup 14}C and long half-life, it is of interest to quantify the amounts released by nuclear industry. The Brazilian nuclear central named Nuclear Central Admiral Alvaro Alberto (CNAAA) has two nuclear reactors of PWR type in operation, Angra I (657 MWe) and Angra II (1350 MWe), and one under construction, Angra III (1309 MWe PWR). The aim of this study was to determine the strength of the sources and the {sup 14}C content in the environment ...