The efficacy of hyperbaric oxygen in modifying the response of tissue to irradiation in doses of 200-400 rad per fraction

International Nuclear Information System (INIS)

Suit, D.D.; Orsi, L.

1975-01-01

The efficacy of respiration of O 2 at 30 psi in modifying the response of normal and tumour tissue to irradiation administered at 200 to 400 rad per fraction to anaesthetized mice has been evaluated. End-points have been delay in growth and TCD 50 for an early generation iso-transplant of a C 3 H mouse mammary carcinoma, and the acute reaction of skin of the C 3 H/Sed mouse. Results showed that the ratios of dose (air)/dose (O 2 30 psi) to elicit these end points were in the range 1.2 to 1.4. In earlier work using the same end points but doses per fraction 430 to 2100 rad, the ratios were 1.6 to 1.8. That is, for these tissue responses, respiration of O 2 at 30 psi increases the response of both normal and tumour tissue to all radiation doses tested. It is of greater effectiveness when combined with large doses per fraction, eg. greater than 430 rad. (author)

RBE/absorbed dose relationship of d(50)-Be neutrons determined for early intestinal tolerance in mice

International Nuclear Information System (INIS)

Gueulette, J.; Wambersie, A.

1978-01-01

RBE/absorbed dose relationship of d(50)-Be neutrons (ref.: 60 Co) was determined using intestinal tolerance in mice (LD50) after single and fractionated irradiation. RBE is 1.8 for a single fraction (about 1000 rad 60 Co dose); it increases when decreasing dose and reaches the plateau value of 2.8 for a 60 Co dose of about 200 rad. This RBE value is used for the clinical applications with the cyclotron 'Cyclone' at Louvain-la-Neuve [fr

Variation in U.V. primary fluorescence-intensity of vital cells depending on 60Co γ-radiation dose

International Nuclear Information System (INIS)

Merkle, K.

1978-01-01

Using impulse-cytofluorophotometry in the ultra-violet spectral region it has been shown on vital, unstained Ehrlich ascites tumour cells that the primary fluorescence intensity of this tumour was on day 11 after transplantation 20 per cent higher than on day 8. Storage of the vital cells for 25 min at 20 0 C had no effect on this result. When the cells were exposed to 60 Co γ-radiation on day 6, a new stable fluorescence level was established after 20 hours. Measurements of the primary fluorescence intensity depending on dose have shown a significant rise starting from 75 rad at 48 hours after irradiation. The fluorescence intensity rose by 42.5 per cent of the control value at 3000 rad, but only by 31.5 per cent on exposure to 4000 rad. (author)

Ten years medical follow-up of four persons accidentally exposed to 60Co γ-rays

International Nuclear Information System (INIS)

Liu, Liqun; Zhao, Wenzheng; Wang, Jingying

1984-01-01

Four cases of acute radiation injury resulting from accidental exposure to a 60 Co source in February, 1972, were subject to early medical examination, and followed-up for 10 years. Their whole body exposure doses were estimated to be 55-147 rads. The results showed that in the individuals who had received a single dose below 147 rads, the temporary clinical picture, and the injuries in hemopoietic function and male reproductive system were all recoverable, but the chromosome aberrations yield returned to normal slowly. Ten years after the accident, all these 4 cases were in good health, and no cataract or malignant diseases were observed. No obvious abnormalities were found in their children. (author)

Effects of prenatal 60Co irradiation on postnatal neural, learning, and hormonal development of the squirrel monkey

International Nuclear Information System (INIS)

Ordy, J.M.; Brizzee, K.R.; Dunlap, W.P.; Knight, C.

1982-01-01

The goals of this study were to examine the effects of 0, 50, and 100 rad of 60 Co administered prenatally on postnatal development of neuromuscular coordination, visual discrimination learning, spontaneous light-dark stabilimeter activity, plasma cortisol, and somatometric growth rates of diurnal squirrel monkeys from birth to 90 days. In terms of accuracy, completeness, and time required for performance of reflexes and neuromuscular coordination, the performance of 50- and 100-rad offspring was less accurate and poorly coordinated and required more time for completion to that of controls. In visual orientation, discrimination, and reversal learning, the percentage correct responses of the 50- and 100-rad offspring were significantly lower than those of controls. Spontaneous light-dark stabilimeter activity of 50- and 100-rad offspring was significantly higher in the dark session than that of controls. Plasma cortisol was significantly higher in 100-rad infants than in controls. Comparisons of somatometric growth rates indicated that postnatal head circumference, crown-rump length, and to a lesser extent body weight increased at significantly slower rates in 50- and 100-rad offspring. These findings should provide essential information for formulating and carrying out multivariate behavioral, biochemical, and morphometric assessments of low-dose effects on the brain of primate offspring within demonstrable dose-response curves

Small Rad51 and Dmc1 Complexes Often Co-occupy Both Ends of a Meiotic DNA Double Strand Break.

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M Scott Brown

2015-12-01

Full Text Available The Eukaryotic RecA-like proteins Rad51 and Dmc1 cooperate during meiosis to promote recombination between homologous chromosomes by repairing programmed DNA double strand breaks (DSBs. Previous studies showed that Rad51 and Dmc1 form partially overlapping co-foci. Here we show these Rad51-Dmc1 co-foci are often arranged in pairs separated by distances of up to 400 nm. Paired co-foci remain prevalent when DSBs are dramatically reduced or when strand exchange or synapsis is blocked. Super-resolution dSTORM microscopy reveals that individual foci observed by conventional light microscopy are often composed of two or more substructures. The data support a model in which the two tracts of ssDNA formed by a single DSB separate from one another by distances of up to 400 nm, with both tracts often bound by one or more short (about 100 nt Rad51 filaments and also by one or more short Dmc1 filaments.

Dynamic changes of peripheral blood T-lymphocyte DNA-Synthesis in rabbits after fractionated and single exposure to 60Co-γ rays

International Nuclear Information System (INIS)

Wang Zongwu; Chen Tiehe; Yu Zhijie; Han Ling; Pan Yusha; Su Fuqiang

1988-01-01

The experiments in 59 rabbits γ-irradiated with doses of 0, 0.5, 1.0, 2.0, and 3.0 Gy in fractional and single exposure to 60 Co-γ rays were reported, respectively · Dynamics of the changes of DNA-Synthesis in T-lymphocytes of peripheral blood was obserced during 29 days after γ-irradiation. Marked inhibition in DNA-synthesis was found on 1st day after irradiation. Recovery was observed in 3rd day after irradiation. The levels of DNA-synthesis before irradiation was recovered on 7th day after exposure for all groups. For fractionated irradiation, however, an increase, rather than a decrese, of DNA-synthesis was in the group of 1.0 Gy

Affinity purification and partial characterization of a yeast multiprotein complex for nucleotide excision repair using histidine-tagged Rad14 protein

International Nuclear Information System (INIS)

Rodriguez, K.; Talamantez, J.; Huang, W.; Reed, S.H.; Wang, Z.; Chen, L.; Feaver, W.J.; Friedberg, E.C.; Tomkinson, A.E.

1998-01-01

The nucleotide excision repair (NER) pathway of eukaryotes involves approximately 30 polypeptides. Reconstitution of this pathway with purified components is consistent with the sequential assembly of NER proteins at the DNA lesion. However, recent studies have suggested that NER proteins may be pre-assembled in a high molecular weight complex in the absence of DNA damage. To examine this model further, we have constructed a histidine-tagged version of the yeast DNA damage recognition protein Rad14. Affinity purification of this protein from yeast nuclear extracts resulted in the co-purification of Rad1, Rad7, Rad10, Rad16, Rad23, RPA, RPB1, and TFIIH proteins, whereas none of these proteins bound to the affinity resin in the absence of recombinant Rad14. Furthermore, many of the co-purifying proteins were present in approximately equimolar amounts. Co-elution of these proteins was also observed when the nuclear extract was fractionated by gel filtration, indicating that the NER proteins were associated in a complex with a molecular mass of >1000 kDa prior to affinity chromatography. The affinity purified NER complex catalyzed the incision of UV-irradiated DNA in an ATP-dependent reaction. We conclude that active high molecular weight complexes of NER proteins exist in undamaged yeast cells

Specific absorbed fractions of electrons and photons for Rad-HUMAN phantom using Monte Carlo method

International Nuclear Information System (INIS)

Wang Wen; Hu Liqin; Cheng Mengyun; Long Pengcheng

2015-01-01

The specific absorbed fractions (SAF) for self- and cross-irradiation are effective tools for the internal dose estimation of inhalation and ingestion intakes of radionuclides. A set of SAFs of photons and electrons were calculated using the Rad-HUMAN phantom, which is a computational voxel phantom of a Chinese adult female that was created using the color photographic image of the Chinese Visible Human (CVH) data set by the FDS Team. The model can represent most Chinese adult female anatomical characteristics and can be taken as an individual phantom to investigate the difference of internal dose with Caucasians. In this study, the emission of mono-energetic photons and electrons of 10 keV to 4 MeV energy were calculated using the Monte Carlo particle transport calculation code MCNP. Results were compared with the values from ICRP reference and ORNL models. The results showed that SAF from the Rad-HUMAN have similar trends but are larger than those from the other two models. The differences were due to the racial and anatomical differences in organ mass and inter-organ distance. The SAFs based on the Rad-HUMAN phantom provide an accurate and reliable data for internal radiation dose calculations for Chinese females. (authors)

Dose rate and dose fractionation studies in total body irradiation of dogs

International Nuclear Information System (INIS)

Kolb, H.J.; Netzel, B.; Schaffer, E.; Kolb, H.

1979-01-01

Total body irradiation (TBI) with 800-900 rads and allogeneic bone marrow transplantation according to the regimen designated by the Seattle group has induced remissions in patients with otherwise refractory acute leukemias. Relapse of leukemia after bone marrow transplantation remains the major problem, when the Seattle set up of two opposing 60 Co-sources and a low dose rate is used in TBI. Studies in dogs with TBI at various dose rates confirmed observations in mice that gastrointestinal toxicity is unlike toxicity against hemopoietic stem cells and possibly also leukemic stem cells depending on the dose rate. However, following very high single doses (2400 R) and marrow infusion acute gastrointestinal toxicity was not prevented by the lowest dose rate studied (0.5 R/min). Fractionated TBI with fractions of 600 R in addition to 1200 R (1000 rads) permitted the application of total doses up to 300 R followed by marrow infusion without irreversible toxicity. 26 dogs given 2400-3000 R have been observed for presently up to 2 years with regard to delayed radiation toxicity. This toxicity was mild in dogs given single doses at a low dose rate or fractionated TBI. Fractionated TBI is presently evaluated with allogeneic transplants in the dog before being applied to leukemic patients

Genetic injury in hybrid male mice exposed to low doses of 60CO γ-rays or fission neutrons. 1

International Nuclear Information System (INIS)

Grahn, D.; Carnes, B.A.; Farrington, B.H.; Lee, C.H.

1984-01-01

Young adult male B6CF 1 mice were exposed to single whole body doses of fission neutrons or 60 Co γ rays. Postspermatogonial dominant lethal injury, incidence of reciprocal chromosome translocations induced in spermatogonia, incidence of abnormal epididymal sperm 4-6 weeks after exposure, and testis weight loss 3-6 weeks after exposure were all measured. Significant effects were seen at 1 and 2.5 rad of neutrons consistent with extrapolation from higher doses, with the exception of dominant lethal mutations, which occurred in significant excess of expectation. Dose-response functions were linear or linear-quadratic, depending upon end point, radiation quality, and dose range. For translocation frequencies, the D 2 term was negative for neutron and positive for γ-ray irradiations. RBE values varied with dose and end point. For testis weight loss and abnormal sperm over the full dose range, the RBEs were between 5 and 6. They were between 7 and 9 at lower doses (< 10 rad) for translocations. RBEs for postimplantation and total dominant lethal rates were 5-6 above 10 rad and 10-14 below 10 rad. The RBEs for preimplant losses were between 15 and 25 above 10 rad and possibly higher below 10 rad, although the data are statistically 'noisy'. (Auth.)

Performance of the RAD-57 pulse CO-oximeter compared with standard laboratory carboxyhemoglobin measurement.

Science.gov (United States)

Touger, Michael; Birnbaum, Adrienne; Wang, Jessica; Chou, Katherine; Pearson, Darion; Bijur, Polly

2010-10-01

We assess agreement between carboxyhemoglobin levels measured by the Rad-57 signal extraction pulse CO-oximeter (RAD), a Food and Drug Administration-approved device for noninvasive bedside measurement, and standard laboratory arterial or venous measurement in a sample of emergency department (ED) patients with suspected carbon monoxide poisoning. The study was a cross-sectional cohort design using a convenience sample of adult and pediatric ED patients in a Level I trauma, burn, and hyperbaric oxygen referral center. Measurement of RAD carboxyhemoglobin was performed simultaneously with blood sampling for laboratory determination of carboxyhemoglobin level. The difference between the measures for each patient was calculated as laboratory carboxyhemoglobin minus carboxyhemoglobin from the carbon monoxide oximeter. The limits of agreement from a Bland-Altman analysis are calculated as the mean of the differences between methods ±1.96 SDs above and below the mean. Median laboratory percentage carboxyhemoglobin level was 2.3% (interquartile range 1 to 8.5; range 0% to 38%). The mean difference between laboratory carboxyhemoglobin values and RAD values was 1.4% carboxyhemoglobin (95% confidence interval [CI] 0.2% to 2.6%). The limits of agreement of differences of measurement made with the 2 devices were -11.6% and 14.4% carboxyhemoglobin. This range exceeded the value of ±5% carboxyhemoglobin defined a priori as clinically acceptable. RAD correctly identified 11 of 23 patients with laboratory values greater than 15% carboxyhemoglobin (sensitivity 48%; 95% CI 27% to 69%). There was one case of a laboratory carboxyhemoglobin level less than 15%, in which the RAD device gave a result greater than 15% (specificity of RAD 96/97=99%; 95% CI 94% to 100%). In the range of carboxyhemoglobin values measured in this sample, the level of agreement observed suggests RAD measurement may not be used interchangeably with standard laboratory measurement. Copyright © 2010 American

RADTRAN 6/RadCat 6 user guide.

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Weiner, Ruth F.; Hinojosa, Daniel; Heames, Terence John; Farnum, Cathy Ottinger; Kalinina, Elena Arkadievna

2013-09-01

This document provides a detailed discussion and a guide for the use of the RadCat 6.0 Graphical User Interface input file generator for the RADTRAN code, Version 6. RadCat 6.0 integrates the newest analysis capabilities of RADTRAN 6.0, including an economic model, updated loss-of-lead shielding model, a new ingestion dose model, and unit conversion. As of this writing, the RADTRAN version in use is RADTRAN 6.02.

An interspecies comparison of responses of mice and dogs to continuous 60Co γ irradiation

International Nuclear Information System (INIS)

Norris, W.P.; Tyler, S.A.; Sacher, G.A.

1976-01-01

Young-adult purebred beagle dogs were exposed continuously, 22h/d, to 60 Co γ rays until they died. The daily dose rates ranged from 3.5 to 210 rad. At 3.5 rad/d the mean survival time was in excess of 1860 days (the study was still in progress in Nov.1975), while at 210 rad/d mean survival time was 13 days. The data are compared with those from previously published information from similarly irradiated mice. The comparison is made in terms of radiation-specific death rate, defined as 1/MASsub(i)-1/MASsub(c), where MASsub(i) and MASsub(c) are the mean after-survival times of the irradiated and control populations, respectively. In both species, when log radiation-specific death rate is plotted against log dose rate, the response has a slope=2, i.e. the death rate increases with the square of dose rate. This occurs over the entire dose rate range where damage to haematopoietic tissues is the primary cause of death. In the mouse, at daily dose rates below 20 rad/d, haematopoietic injury is no longer a primary cause of death and the response curve shifts to slope=1 where injury is dependent only on total accumulated dose and is independent of dose rate. The data available so far suggest that a similar inflection may occur with the dog at dose rates below 3.5 rad/d. An experiment is being initiated to determine whether this will be the case. Statistical considerations, essential to the design of the study, are presented. (author)

Experimental studies on the influence of irradiation (60Co) on wound healing of colonic suture

International Nuclear Information System (INIS)

Shoji, Munehiro

1980-01-01

Effects of preoperative 60 Co irradiation on wound healing of colonic suture in adult dogs of mixed breed were discussed. Wound healing 7 days after colonic suture was compared among dogs which received colonic suture immediately, or 3 days, or 7 days after the 60 Co irradiation. As a result, there was not a big difference in their wound healing among these dogs, and disorders of wound healing were not found. Bursting pressure at sutured sites was always lower in irradiated dogs than controls. Recovery of the bursting pressure was 2 days slower in irradiated dogs than non-irradiated dogs for 7 days after the suture. Bursting pressure was the lowest on the 3rd day after the suture in both groups. As to fine changes in irradiated dogs, appearance of recommunicating phenomena in blood vessels, delay of a decrease in avascular regions, delay of granulation, and hypertrophy of vascular walls seemed to be influenced by 60 Co irradiation, but there was not a big difference in these results between irradiated and non-irradiated dogs. An increase in postoperative concentration of hydroproline tended to be little lower in irradiated dogs than controls, which seemed to be influenced by the 60 Co irradiation. This result was also suggested from delay of granulation and remaining inflammations. Effects of 60 Co irradiation on wound healing of colonic suture seemed to be slight generally, because ruptured suture scarecely occurred in the irradiated dogs. When doses used in this experiment were calculated roughly by Ellis's method, irradiation of 60 Co seemed not to influence seriously wound healing if the total of 2,000 to 2,500 rad was irradiated in 8 to 10 doses to human colon. (Tsunoda, M.)

Fractional CO2 laser treatment for vaginal laxity: A preclinical study.

Science.gov (United States)

Kwon, Tae-Rin; Kim, Jong Hwan; Seok, Joon; Kim, Jae Min; Bak, Dong-Ho; Choi, Mi-Ji; Mun, Seok Kyun; Kim, Chan Woong; Ahn, Seungwon; Kim, Beom Joon

2018-05-07

Various studies have investigated treatment for vaginal laxity with microablative fractional carbon dioxide CO 2 laser in humans; however, this treatment has not yet been studied in an animal model. Herein, we evaluate the therapeutic effects of fractional CO 2 laser for tissue remodeling of vaginal mucosa using a porcine model, with the aim of improving vaginal laxity. The fractional CO 2 laser enables minimally invasive and non-incisional procedures. By precisely controlling the laser energy pulses, energy is sent to the vaginal canal and the introitus area to induce thermal denaturation and contraction of collagen. We examined the effects of fractional CO 2 laser on a porcine model via clinical observation and ultrasound measurement. Also, thermal lesions were histologically examined via hematoxylin-eosin staining, Masson's trichrome staining, and Elastica van Gieson staining and immunohistochemistry. The three treatment groups, which were determined according to the amount of laser-energy applied (60, 90, and 120 mJ), showed slight thermal denaturation in the vaginal mucosa, but no abnormal reactions, such as excessive hemorrhaging, vesicles, or erythema, were observed. Histologically, we also confirmed that the denatured lamina propria induced by fractional CO 2 laser was dose-dependently increased after laser treatment. The treatment groups also showed an increase in collagen and elastic fibers due to neocollagenesis and angiogenesis, and the vaginal walls became firmer and tighter because of increased capillary and vessel formation. Also, use of the fractional CO 2 laser increased HSP (heat shock protein) 70 and collagen type I synthesis. Our results show that microablative fractional CO 2 laser can produce remodeling of the vaginal connective tissue without causing damage to surrounding tissue, and the process of mucosa remodeling while under wound dressings enables collagen to increase and the vaginal wall to become thick and tightened. Lasers Surg. Med

Schizosaccharomyces pombe Rad22A and Rad22B have similar biochemical properties and form multimeric structures

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Vries, Femke A.T. de [Department of Toxicogenetics, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden (Netherlands); Zonneveld, Jose B.M. [Department of Toxicogenetics, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden (Netherlands); Groot, Anton J. de [Department of Toxicogenetics, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden (Netherlands); Koning, Roman I. [Department of Molecular Cell Biology, Leiden University Medical Center, Leiden (Netherlands); Zeeland, Albert A. van [Department of Toxicogenetics, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden (Netherlands); Pastink, Albert [Department of Toxicogenetics, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden (Netherlands)]. E-mail: A.Pastink@lumc.nl

2007-02-03

The Saccharomyces cerevisiae Rad52 protein has a crucial role in the repair of DNA double-strand breaks by homologous recombination. In vitro, Rad52 displays DNA binding and strand annealing activities and promotes Rad51-mediated strand exchange. Schizosaccharomyces pombe has two Rad52 homologues, Rad22A and Rad22B. Whereas rad22A deficient strains exhibit severe defects in repair and recombination, rad22B mutants have a much less severe phenotype. To better understand the role of Rad22A and Rad22B in double-strand break repair, both proteins were purified to near homogeneity. Using gel retardation and filter binding assays, binding of Rad22A and Rad22B to short single-stranded DNAs was demonstrated. Binding of Rad22A to double-stranded oligonucleotides or linearized plasmid molecules containing blunt ends or short single-stranded overhangs could not be detected. Rad22B also does not bind efficiently to short duplex oligonucleotides but binds readily to DNA fragments containing 3'-overhangs. Rad22A as well as Rad22B efficiently promote annealing of complementary single-stranded DNAs. In the presence of Rad22A annealing of complementary DNAs is almost 90%. Whereas in reactions containing Rad22B the maximum level of annealing is 60%, most likely due to inhibition of the reaction by duplex DNA. Gel-filtration experiments and electron microscopic analyses indicate self-association of Rad22A and Rad22B and the formation of multimeric structures as has been observed for Rad52 in yeast and man.

Metabolism of 60Co in mollusca

International Nuclear Information System (INIS)

Nakahara, Motokazu

1983-01-01

After mollusca were bred in 60 Co-labeled sea water or were given 60 Co-labeled feed for certain hours, their tissues including the liver were removed as experimental samples. 60 Co metabolism was observed by the Sephadex gel filtration profile. A gel chromatogram of the liver in gastropoda showed a marked peak of 60 Co on the high-molecular side. Although the peak was observed on both high- and low-molecular sides in pelecypoda, it was more marked on the high-molecular side than on the low-molecular side. In cephalopoda, the peak pattern was similar to that in the other mollusca, but the proportion of low-molecular components was comparatively large. The gel filtration profile of 60 Co in various tissues of cephalopoda revealed the incorporation of 60 Co into the high-molecular components in blood, three peaks in the kidneys, and the incorporation of 60 Co into the low-molecular components in the branchial heart. The metabolism of 60 Co was dependent upon the chemical form of Co in gastropoda, and organic 60 Co was specifically observed in the high-molecular components. (Namekawa, K.)

RadCat 3.0 user guide.

Energy Technology Data Exchange (ETDEWEB)

Hinojosa, Daniel; Penisten, Janelle J.; Dennis, Matthew L.; Osborn, Douglas M.; Weiner, Ruth F.; Heames, Terence John; Marincel, Michelle K.

2009-05-01

RADTRAN is an internationally accepted program and code for calculating the risks of transporting radioactive materials. The first versions of the program, RADTRAN I and II, were developed for NUREG-0170 (USNRC, 1977), the first environmental statement on transportation of radioactive materials. RADTRAN and its associated software have undergone a number of improvements and advances consistent with improvements in both available data and computer technology. The version of RADTRAN currently bundled with RadCat is RADTRAN 6.0. This document provides a detailed discussion and a guide for the use of the RadCat 3.0 Graphical User Interface input file generator for the RADTRAN code. RadCat 3.0 integrates the newest analysis capabilities of RADTRAN 6.0 which includes an economic model, updated loss-of-lead shielding model, and unit conversion. As of this writing, the RADTRAN version in use is RADTRAN 6.0.

Melting decontamination and free release of metal waste at Studsvik RadWaste Co. in Sweden

International Nuclear Information System (INIS)

Kawatsuma, Shinji; Ishikawa, Keiji; Matsubara, Tatsuo; Donomae, Yasushi; Imagawa, Yasuhiro

2006-01-01

The Studsvik RadWaste Co. in Sweden was visited on August 29, 2005 by members of radioactive waste and decommissioning subgroup of central safety task force in old Japan Nuclear Cycle Development Institute as 'Overseas investigation'. The visit afforded us the chance to survey melting and decontaminating of metallic waste in this company and the status of free release. Domestic and foreign radioactive metallic waste is accepted in this company after 1987, and the majority of the decontaminated waste have been released freely. In the background of the big effort of this company and the strong leadership of the regulator (SSI: Swedish radiation protection Authority), prosperous operation was able to have been achieved. This survey was done based on 'Free release of radioactive metallic waste in Europe: the free release experience for 17 years at Studsvik RadWaste Co. in Sweden' by Dr. J. Lorenzen. (author)

Rad and Mubad in Shahnameh of Ferdowsi

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z Delpazir

2011-09-01

However, the important points overlooked by explicators are the relationship between Rad and Mubad (Zoroastrian priest and the reason why these two words have co-occurred so frequently in Shahnameh, the most famous Persian national epic. It seems that Rad in Shahnameh, based on Avesta and Pahlavi texts, is often construed as Sadane or Dastoor that was a high position in ancient Iran’s religious hierarchy. Thus, Rads and Mubads were both considered members of religious communities. This study tries to investigate the role and position of Rads and Mubads and their relationship with one another, based on Shahnameh of Ferdowsi, in three chapters: The etymology of Rad Rad in Shahnameh The relationship between Rads and Mubads.

Distribution of 60Co and 54Mn in graphite material of irradiated HTGR fuel assemblies

International Nuclear Information System (INIS)

Hayashi, Kimio; Kikuchi, Teruo; Kobayashi, Fumiaki; Minato, Kazuo; Fukuda, Kousaku; Ikawa, Katsuichi; Iwamoto, Kazumi

1984-05-01

Distribution of 60 Co and 54 Mn was measured in the graphite sleeves and blocks of the third and fourth HTGR fuel assemblies irradiated in the Oarai Gas Loop-1 (OGL-1), which is a high temperature inpile gas loop installed in the Japan Materials Testing Reactor (JMTR) of Japan Atomic Energy Research Institute (JAERI). Axial and circumferential profiles were obtained by gamma spectrometry, and radial profiles by lathe sectioning with gamma spectrometry. Distribution of 60 Co is in good agreement with that of thermal neutron flux, and the Co content in the graphite is estimated to be -- 1 x 10 -9 in weight fraction. Concentration of 54 Mn decreases toward the axial center in its axial profile, and radially is almost uniform inside and appreciably higher at free surfaces. An estimated Fe content of --10 -8 in wight fraction is smaller by two orders of magnitude than that from chemical analysis. Higher concentraion of 60 Co and 54 Mn at the free surfaces suggests the importance of transportation process of these nuclides in the coolant loop. (author)

Rad51-Rad52 mediated maintenance of centromeric chromatin in Candida albicans.

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Sreyoshi Mitra

2014-04-01

Full Text Available Specification of the centromere location in most eukaryotes is not solely dependent on the DNA sequence. However, the non-genetic determinants of centromere identity are not clearly defined. While multiple mechanisms, individually or in concert, may specify centromeres epigenetically, most studies in this area are focused on a universal factor, a centromere-specific histone H3 variant CENP-A, often considered as the epigenetic determinant of centromere identity. In spite of variable timing of its loading at centromeres across species, a replication coupled early S phase deposition of CENP-A is found in most yeast centromeres. Centromeres are the earliest replicating chromosomal regions in a pathogenic budding yeast Candida albicans. Using a 2-dimensional agarose gel electrophoresis assay, we identify replication origins (ORI7-LI and ORI7-RI proximal to an early replicating centromere (CEN7 in C. albicans. We show that the replication forks stall at CEN7 in a kinetochore dependent manner and fork stalling is reduced in the absence of the homologous recombination (HR proteins Rad51 and Rad52. Deletion of ORI7-RI causes a significant reduction in the stalled fork signal and an increased loss rate of the altered chromosome 7. The HR proteins, Rad51 and Rad52, have been shown to play a role in fork restart. Confocal microscopy shows declustered kinetochores in rad51 and rad52 mutants, which are evidence of kinetochore disintegrity. CENP-ACaCse4 levels at centromeres, as determined by chromatin immunoprecipitation (ChIP experiments, are reduced in absence of Rad51/Rad52 resulting in disruption of the kinetochore structure. Moreover, western blot analysis reveals that delocalized CENP-A molecules in HR mutants degrade in a similar fashion as in other kinetochore mutants described before. Finally, co-immunoprecipitation assays indicate that Rad51 and Rad52 physically interact with CENP-ACaCse4 in vivo. Thus, the HR proteins Rad51 and Rad52

Correlation of RAD51 and radiosensitization of methotrexate

International Nuclear Information System (INIS)

Du Liqing; Bai Jianqiang; Liu Qiang; Wang Yan; Zhao Peng; Chen Fenghua; Wang Hong; Fan Feiyue

2012-01-01

Objective: To evaluate the correlation between homologous recombination repair protein RAD51 and methotrexate-enhanced radiosensitivity. Methods: Western blot and RT-PCR assays were used to detect RAD51 expression in HOS osteosarcoma cells exposed to γ-ray irradiation alone and in combination with methotrexate. Colony formation assay was used to test the survival fraction of HOS cells exposed to γ-rays and methotrexate. Results: Methotrexate inhibited both protein and RNA expressions of RAD51, and the combination of radiation and methotrexate enhanced the inhibition of RAD51 expression. Moreover, transfection of cells with RAD51 gene decreased cellular sensitivity to methotrexate and γ-rays. The sensitizer enhancement ratios after irradiation in combination with methotrexate were 1.51 and 0.99, respectively. Methotrexate was a preferred radiosensitizer to HOS cell. Conclusions: RAD51 might be involved in the methotrexate-enhanced radiosensitivity. (authors)

Immediate changes in estimated cardiac output and vascular resistance after 60Co exposure in monkeys: implication for performance decrement

International Nuclear Information System (INIS)

Bruner, A.

1977-01-01

Aortic blood flow velocity, blood pressure, and heart rate were recorded in 12 unanesthetized, nonperforming monkeys during exposure to 1000 rad 60 Co at 129--164 rad/min. The first postradiation changes were seen within 3--4 min of the exposure's start and included tachycardia, a transient hypotension secondary to a loss in peripheral resistance, and a brief increase followed by a decrease to subnormal levels in cardiac output. The lowest cardiac output occurred between 10 and 20 min postexposure while blood pressure and peripheral resistance were recovering. It was proposed that the concurrent combination of low cardiac output, low blood pressure, and supranormal peripheral resistance might sufficiently attenuate cerebral perfusion temporarily to account for the transient behavioral decrements often seen during this time. Histamine release was postulated as responsible for this vascular shock syndrome

Mantle treatment of Hodkin's disease with 60Co gamma rays

International Nuclear Information System (INIS)

Svahn-Tapper, G.

1979-01-01

60 Co mantle beams were used in the radiation treatment of patients| with Hodgkin's disease. A technique using beam-flattening filters is described. The dosimetry was based on dose plans drawn up manually for each patient. The good dosimetric accuracy of the method was verified by in vivo measurements of absorbed dose at the oesophagi of 60 patients. Split-course treatment with 40 Gy was given in 27 fractions over 71 days. Results and side-effects in 90 patients are analyzed. The local recurrence rate was 3 %. (author)

Effect of low-dose 60Co gamma irradiation on the photosynthetic activity of maize seedlings

International Nuclear Information System (INIS)

Turcsanyi, G.

1979-01-01

Photosynthesis investigations were carried out on maize seedlings treated with 1000 rad of 60 Co gamma irradiation prior to sowing. The aim of the work was to find out, to what degree the individual processes of photosynthesis are affected by small doses of irradiation. The increase in weight, the chlorophyll a, chlorophyll b and carotinoid content as well as the photosynthetic O 2 -evolution and 14 CO 2 -fixation of the seedlings were measured. The results indicate that, in contradiction to the data given in the literature, the occasional increase in weight caused by small-dose irradiation is not in connection with the membrane-bound part of the photosynthetic apparatus, but it is the consequence of the increased activity of the Calvin-cycle enzymes in the stroma of the chloroplasts. (author)

A novel interation of nucleolin with Rad51

International Nuclear Information System (INIS)

De, Ananya; Donahue, Sarah L.; Tabah, Azah; Castro, Nancy E.; Mraz, Naomi; Cruise, Jennifer L.; Campbell, Colin

2006-01-01

Nucleolin associates with various DNA repair, recombination, and replication proteins, and possesses DNA helicase, strand annealing, and strand pairing activities. Examination of nuclear protein extracts from human somatic cells revealed that nucleolin and Rad51 co-immunoprecipitate. Furthermore, purified recombinant Rad51 associates with in vitro transcribed and translated nucleolin. Electroporation-mediated introduction of anti-nucleolin antibody resulted in a 10- to 20-fold reduction in intra-plasmid homologous recombination activity in human fibrosarcoma cells. Additionally, introduction of anti-nucleolin antibody sensitized cells to death induced by the topoisomerase II inhibitor, amsacrine. Introduction of anti-Rad51 antibody also reduced intra-plasmid homologous recombination activity and induced hypersensitivity to amsacrine-induced cell death. Co-introduction of anti-nucleolin and anti-Rad51 antibodies did not produce additive effects on homologous recombination or on cellular sensitivity to amsacrine. The association of the two proteins raises the intriguing possibility that nucleolin binding to Rad51 may function to regulate homologous recombinational repair of chromosomal DNA

Molecular exclusion chromatographic analysis on 60Co irradiated rattlesnake

International Nuclear Information System (INIS)

Murata, Y.; Rogero, J.R.

1988-07-01

Ionizing radiations are sufficiently energetic to be able of breaking chemical bonds and as result of that molecules of substances present in the irradiated will be chemically changed and their biological properties affected also. In this paper the effects of gamma radiation of Co-60 on the rattlesnake venom were studied. A pool of positive crotamina Crotalus durissus terrificus venom was dissolved in 0,15 M NaCl and irradiated with Co-60. Doses of 100, 250, 500, 750, 1500 and 2000 Gy were applied at the dose rate of 1190 Gy/h. With doses over 500 Gy the solutions became turbid, suggesting the presence of aggregates and structural changes of the proteins. The concentration of proteins from the filtered solution was measured by the Lowry method. One ml samples were measured at 230 nm. The partition coefficients and the areas of the three main fraction obtained were calculated. (author) [pt

RAD9, RAD17; RAD24, and RAD53 control one pathway of resistance to γ irradiation in Saccharomyces cerevisiae

International Nuclear Information System (INIS)

Koltovaya, N.A.; Nikulushkina, Yu.V.; Roshina, M.P.; Devin, A.B.

2009-01-01

Mechanisms for the genetic control of the cell cycle transition (checkpoint control) have been studied in more detail in yeast Saccharomyces cerevisiae. To clarify tho role of the RAD9, RAD17, RAD24, and RAD53 checkpoint genes in cell radioresistance, diploid double mutants were analyzed for cell sensitivity to ionizing radiation. All mutations in combination with rad9Δ were shown to manifest the epistatic type of interaction. Our results suggest that the RAD9, RAD17, RAD24, and RAD53 checkpoint genes belong to a single epistasis group called the RAD9 group and participate in the same pathway. RAD9 and RAD53 have a positive effect on sensitivity to γ irradiation, whereas RAD17 and RAD24 have a negative effect. For haploid interactions between mutations may differ in the case of γ or UV irradiation, mutations - for example, rad9Δ and rad24Δ - were shown to have an additive effect in the first case and epistatic - in the second. The analyzed genes can also participate in minor mechanisms of radioresistance that are relatively independent of the above major mechanism

60Co levels in the seawater regions

International Nuclear Information System (INIS)

Yoshioka, Mitsuo

1983-01-01

In order to assess the contribution from nuclear power facilities to the 60 Co levels in seawater regions, it is essential to grasp the background values of 60 Co. The following matters are described: 60 Co sources and the respective inputs; nuclear test fallout and nuclear power plants; the 60 Co levels in overseas countries; the 60 Co levels in Japan; the 60 Co levels from nuclear power plants in Fukui prefecture. In the seawater regions around Japan, there have been numerous instances of 60 Co detection; several pCi/kg of dry earth in sea bottom earth and about 1 pCi/kg of raw material in marine life can be considered as the background levels due to nuclear test fallout and nuclear-powered submarines. In the seawater regions of Fukui prefecture, the 60 Co levels appreciably exceeded the above background due to the nuclear power plants, which are insignificant concerning the radiation exposure of the local people. (Mori, K.)

Effects of testicular irradiation with 60Co in guinea pigs CAVIA PORCELLUS

International Nuclear Information System (INIS)

Santos, O.R. dos.

1980-01-01

Improvements were made in restaint systems and in the technique of electroejaculation in guinea pigs, emphasizing safety, effectiveness and repetition. Arrangements for simultaneous testicular irradiation with 60 Co in 5 animals and a phantom to test dose levels in the target region and scattering were also made. Effects of single and fractionated exposures on sperm were studied. A collimated point-shaped 60 Co-machine calibrated to 7 R/min was used as radiation source. Groups of five 12 month aged male guinea pigs were exposed to either single testicular irradiation of 50, 100, 200 and 400 R or fractionated weekly testicular irradiation of 2, 5, 10 and 20 R, during 10 weeks. A last group was exposed to 4 fractionated testicular irradiations of 20 R at time intervals of 21 days and a group of 8 animals was used as control. Semen samples evaluations were made during 5 weeks before irradiation and in the subsequent 11 weeks. Abnormalities in sperm morphology were studied by William's method and phase contrast microscopy. Mean percentages of semen normal espermatzoons and spermatic abnormalities are shown in figures and photomicrographs. Marked differences on concentration, sperm motility and sperm abnormalities were found, but not on volume, in favour of 100 and 200 R single doses levels, as compared to fractionated 10 and 20 R. (Author) [pt

Interactions of checkpoint-genes RAD9, RAD17, RAD24 and RAD53 determining radioresistance of Yeast Saccharomyces Cerevisiae

International Nuclear Information System (INIS)

Koltovaya, N.A.; Nikulushkina, Yu.V.; Roshchina, M.P.; Devin, A.B.

2007-01-01

The mechanisms of genetic control of progress through the division cell cycle (checkpoint-control) in yeast Saccharomyces cerevisiae have been studied intensively. To investigate the role of checkpoint-genes RAD9, RAD17, RAD24, RAD53 in cell radioresistance we have investigated cell sensitivity of double mutants to γ-ray. Double mutants involving various combinations with rad9Δ show epistatic interactions, i.e. the sensitivity of the double mutants to γ-ray was no greater than that of more sensitive of the two single mutants. This suggests that all these genes govern the same pathway. This group of genes was named RAD9-epistasis group. It is interesting to note that the genes RAD9 and RAD53 have positive effect but RAD17 and RAD24 have negative effect on radiosensitivity of yeast cells. Interactions between mutations may differ depending on the agent γ-ray or UV-light, for example mutations rad9Δ and rad24Δ show additive effect for γ-ray and epistatic effect for UV-light

In vitro response of the human breast cancer cell line MDAMB-231 and human peripheral blood mononuclear cells exposed to 60Co at single fraction

International Nuclear Information System (INIS)

Andrade, Lidia Maria; Campos, Tarcisio Passos Ribeiro de; Leite, M.F.; Goes, A.M.

2005-01-01

Radiotherapy using gamma rays is a common modality of breast cancer treatment. The aim of this research is to investigate the biological response of the human breast cancer cell line MDAMB-231 and human peripheral blood mononuclear cells (PBMC) exposed in vitro to 60 Co irradiation at a single fraction of 10 Gy, 25 Gy and 50 Gy doses at 136,4 cGy.min -1 rate. Cells were irradiated at room temperature by the Theratron 80 radiotherapy system. Biological response was evaluated through cellular viability using MTT assay and nucleus damages visualized by Propidium Iodide assay and electrophoresis agarose gel after gamma irradiation. Nucleus damages induced by 60 Co irradiation were compared to damage caused by cell exposure to 10% methanol. The 50 Gy dose of irradiation did not stimulate nucleus damages at the same level as that affected by 10% methanol induction in the MDAMB-231. Further studies are necessary to understand these mechanisms in the MDAMB-231 human breast carcinoma cell line.(author)

Total integrated dose testing of solid-state scientific CD4011, CD4013, and CD4060 devices by irradiation with CO-60 gamma rays

Science.gov (United States)

Dantas, A. R. V.; Gauthier, M. K.; Coss, J. R.

1985-01-01

The total integrated dose response of three CMOS devices manufactured by Solid State Scientific has been measured using CO-60 gamma rays. Key parameter measurements were made and compared for each device type. The data show that the CD4011, CD4013, and CD4060 produced by this manufacturers should not be used in any environments where radiation levels might exceed 1,000 rad(Si).

Comparison of the effects of 50 MeV/sub d → Be/ neutron and cobalt-60 irradiation of the kidneys of Rhesus monkeys

International Nuclear Information System (INIS)

Raulston, G.L.; Gray, K.N.; Gleiser, C.A.; Jardine, J.H.; Flow, B.L.; Huchton, J.I.; Bennett, K.R.; Hussey, D.H.

1978-01-01

Twenty rhesus monkeys had one kidney irradiated (after undergoing unilateral nephrectomies) with one of four doses: 960 or 1080 rads of 50 MeV/sub d→Be/ neutrons, or 2350 or 2700 rads of 60 Co. Whereas animals treated with the lower dose of neutrons or 60 Co are alive with relatively normal renal function, those treated with the higher dose of neutrons died of radiation nephritis. Animals treated with the higher dose of 60 Co developed radiation nephritis but survived. The physiological and histopathological changes of radiation nephritis secondary to neutron irradiation are not qualitatively different from those reported for radiation nephritis secondary to photon irradiation

Study on adsorption of 60Co in soils and minerals and transportation of 60Co in bean-soil system

International Nuclear Information System (INIS)

Feng Yonghong; Chen Chuanqun; Wang Shouxiang; Zhang Yongxi; Sun Zhiming

1998-02-01

The adsorption and desorption of 60 Co in soils and minerals, and the transportation, accumulation, distribution in bean-soil system are studied. The results are as follows: (1) 60 Co was adsorbed rapidly and desorbed difficultly by soils and minerals. The order of the saturated adsorption rate and K d (distribution coefficient) of 60 Co at the balance value was: kieselguhr>paddy soil (loamy clay)>yellowish red soil>kaoline>perlite>silt-loamy soil. The order of D f (desorption factor) value was: yellowish red soil>silt-loamy soil>kaoline>perlite>paddy soil (loamy clay)>kieselguhr. The dynamic behavior of 60 Co in the soils and minerals could be described as a closed two--compartment model. (2) After 60 Co was introduced to the bean-soil system, the concentration of 60 Co in the root is about 10.4∼23.3 times of that in the stalk, and 30 times of that in the bean pod. The negative correlation between the concentration of 60 Co in the soil and depth was detected, over 90 per cent of 60 Co was retained within 6 centimeters of the surface layer, the half residual depth was 2 centimeters. An opened two-compartment model was applied to describe the behavior of 60 Co in the bean-soil system

Identification of cloned genes that complement the rad50-1, rad51-1, rad54-3 and rad55-3 mutations in yeast

International Nuclear Information System (INIS)

Calderon, I.L.; Contopoulou, C.R.; Mortimer, R.K.

1982-01-01

Plasmids that complement the rad50-1, rad51-1, rad54-3 and rad55-3 mutations in yeast, have been isolated. They were obtained by transforming strains, carrying the leu2-112 leu2-3 alleles and the particular rad mutation, with YEp13 plasmids containing near random yeast DNA inserts. Rad + clones were identified among the Leu + transformants. Integration by targeting into the RAD55 locus showed that the rad55-3 complementing plasmid contained the actual RAD55 gene. BamHI fragments from each of the plasmids that complement rad50-1, rad51-1 and rad54-3, all of which lacked Rad + activity, were subcloned into the integrating plasmid YIp5 and the hybrid plasmids were used to transform a Rad + Ura - strain to Ura + . By genetic mapping, the rad51 and rad54 subclones were shown to integrate at their respective loci. However, the rad50 subclones integrated at a site unlinked to the RAD50 locus. This suggests that no homology exists between this BamHI fragment and the RAD50 gene. Integration at the RAD54 locus of the rad54 subclone made the host cell Ura + but Rad - ; excision of the plasmid was shown to be x-ray inducible and to restore the Ura - Rad + phenotype. These results indicate that the BamHI fragment of the RAD54 plasmid is internal to the RAD54 gene. We can conclude also that the RAD54 gene is not essential as cells bearing a disrupted copy of this gene are able to survive. Additionally, a plasmid carrying an amber suppressor has been isolated and characterized

Splenic irradiation in the treatment of patients with chronic myelogenous leukemia or myelofibrosis with myeloid metaplasia. Results of daily and intermittent fractionation with and without concomitant hydroxyurea

International Nuclear Information System (INIS)

Wagner, H. Jr.; McKeough, P.G.; Desforges, J.; Madoc-Jones, H.

1986-01-01

Seventeen patients with either chronic myelogenous leukemia (CML) or myelofibrosis with myeloid metaplasia (MMM) received 24 courses of splenic irradiation at this institution from 1973 to 1982. Eleven of the 17 patients had received prior chemotherapy. Patients were treated with 60 Co gamma rays or 6 MV photons. The fraction size ranged from 15 to 100 rad and the total dose per treatment course from 15 to 650 rad, with the exception of one patient who received 1650 rad. Fourteen of 19 courses (71%) given for splenic pain yielded significant subjective relief while 17 of 26 courses given for splenomegaly obtained at least 50% regression of splenic size. Blood counts were carefully monitored before each treatment to limit hematologic toxicity. From this experience, the authors conclude that splenic irradiation effectively palliates splenic pain and reverses splenomegaly in the majority of patients with CML and MMM. Intermittent fractionation (twice or thrice weekly) is more convenient for the patient, appears to be as effective as daily treatment, and may be associated with less hematologic toxicity. Preliminary results of concurrent treatment with splenic irradiation and oral hydroxyurea show promise and warrant further study

Ionizing radiation-induced foci formation of mammalian Rad51 and Rad54 depends on the Rad51 paralogs, but not on Rad52

International Nuclear Information System (INIS)

Veelen, Lieneke R. van; Essers, Jeroen; Rakt, Mandy W.M.M. van de; Odijk, Hanny; Pastink, Albert; Zdzienicka, MaIgorzata Z.; Paulusma, Coen C.; Kanaar, Roland

2005-01-01

Homologous recombination is of major importance for the prevention of genomic instability during chromosome duplication and repair of DNA damage, especially double-strand breaks. Biochemical experiments have revealed that during the process of homologous recombination the RAD52 group proteins, including Rad51, Rad52 and Rad54, are involved in an essential step: formation of a joint molecule between the broken DNA and the intact repair template. Accessory proteins for this reaction include the Rad51 paralogs and BRCA2. The significance of homologous recombination for the cell is underscored by the evolutionary conservation of the Rad51, Rad52 and Rad54 proteins from yeast to humans. Upon treatment of cells with ionizing radiation, the RAD52 group proteins accumulate at the sites of DNA damage into so-called foci. For the yeast Saccharomyces cerevisiae, foci formation of Rad51 and Rad54 is abrogated in the absence of Rad52, while Rad51 foci formation does occur in the absence of the Rad51 paralog Rad55. By contrast, we show here that in mammalian cells, Rad52 is not required for foci formation of Rad51 and Rad54. Furthermore, radiation-induced foci formation of Rad51 and Rad54 is impaired in all Rad51 paralog and BRCA2 mutant cell lines tested, while Rad52 foci formation is not influenced by a mutation in any of these recombination proteins. Despite their evolutionary conservation and biochemical similarities, S. cerevisiae and mammalian Rad52 appear to differentially contribute to the DNA-damage response

Relative contributions of food and water in the accumulation of 60Co by a freshwater fish

International Nuclear Information System (INIS)

Baudin, J.P.; Fritsch, A.F.

1989-01-01

Because of its presence in the natural environment a laboratory research program was undertaken with 60 Co, focused on a freshwater fish, Cyprinus carpio. In this paper results from laboratory experiments conducted to assess the role of food and water in the uptake and retention of 60 Co by the carp are reported. The 60 Co accumulation by the fish from water, from food and from both sources simultaneously were studied during the first phase. After this exposure phase the individuals are transferred to non-radioactive water and/or received unlabelled food to follow depuration of the radionuclide. There was no significant difference between the fish of the 3 treatment groups; the greatest fraction of residual radiocobalt resided in digestive tract that accounted for 20-25% of the total 69 Co body burden. (author)

An experimental study of the effect of irradiation (Co60) on wound healing of the esophagus

International Nuclear Information System (INIS)

Shima, Shingo; Sugiura, Yoshiaki; Yonekawa, Hajime; Ogata, Toshiro; Matsuyama, Shigeo

1982-01-01

The cervical esophagus of 22 adult mongrel dogs was irradiated in a schedule of 300 rad per fraction, 3 times a week, to either a total dose of 3000 or 6000 rad. 2 weeks after completion of irradiation, 1 cm of the esophagus in the irradiation field was resected, and Olsen type 1 layered anastomosis was performed. All of the animals were sacrificed for comparison with a non-irradiated group 2 weeks after surgery. Failure of the sutures occurred in 1 of 18 non-irradiated dogs (5.6%), 1 of 9 dogs given 3000 rad (11.1%), with no significant difference, and 5 of 7 given 6000 rad (71.4%), with a significant difference from the other two groups. Irradiation of 3000 or 6000 rad provoked decrease of the interstitial content of hydroxyproline to 70% or 85%, respectively. Although an increasing tendency was observed 2 weeks after anastomosis, the values of the irradiated groups were lower than those of the non-irradiated group. Histopathologically, a strong reaction, chiefly edema, was noted in the submucosal layer. (Chiba, N.)

Changes of natural killer activity following local 60Co irradiation in intracranial tumor-bearing mice

International Nuclear Information System (INIS)

Otsuka, Shin-ichi; Suda, Kinya; Yamashita, Junkoh; Takeuchi, Juji; Handa, Hajime

1982-01-01

Changes of natural killer activity (NK activity) by local 60 Co irradiation in intracranial tumor-bearing mice were studied by the method of 51 Cr release assay. Local irradiation was administered 10 days after intracranial transplantation of 203-Glioma which had been originally induced by 20-methylcholanthrene in C57BL mice. Irradiation suppressed the growth of tumor and prolonged the mean survival time. The 50% survival time of untreated mice was about 2.5 weeks but that of mice treated by a single dose of 1000 rad and 1500 rad of irradiation was about 4.5 weeks and 6.5 weeks respectively. NK activity of spleen cells in these mice was serially examined. NK activity was gradually increased in mice treated by local irradiation, while it was gradually decreased in mice without treatment. On the other hand, NK activity remained unchanged in non-tumor-bearing control mice. Mice treated with 1000 rad and 1500 rad of irradiation showed 44.0% and 47.6% of % specific 51 Cr release respectively 11 days after irradiation while normal mice showed 18.0%. The increased NK activity after local irradiation suggested that local irradiation might have enhanced the immunological defence mechanisms against the tumor in the tumor-bearing hosts. Some characteristics of effector cells in this assay system were examined. The cytotoxicity of spleen cells was removed by the treatment of anti-BAT serum and complement but was not removed by the treatment of anti-Thy-1.2 serum and complement. Since NK activity reflects the immunological resistance to tumors to some extent, it is felt important to clarify the significance of changes of NK activity in patients with brain tumors in relation to various treatments including surgery, radiotherapy, chemotherapy and immunotherapy in the next step. (author)

Developed and applications of a method for dose comparation of the cobalt 60 in radiotherapy

International Nuclear Information System (INIS)

Leao, J.L.B.

1975-01-01

IAEA and WHO developed a postal intercomparison program for measuring the output of Co-60 therapy units all over the world. This work reports first results of an modified postal intercomparison based on IAEA/WHO program. A mailable 10 x 10 x 10,5cm Mix-D phantom with embedded TLD dosimeters, films and field markers of lead and a questionary were developed to obtain not only informations regarding output of Co-60 therapy machines but also to get information about alignment, field homogeneity, dose calculations, field size and surface dose. This program was field tested in 10 different Radiotherapy Centers. The results of this intercomparison gave a spread of the absorbed dose from 78 rads to 127 rads for the 100 rads asked for in 5cm depth of the phantom. Variation in the prescribed fieldsize of 6 x 6cm were between 30cm 2 and 100cm 2 . In half of the cases inhomogeneity of the radiation field was spotted [pt

In vitro response of the human breast cancer cell line MDAMB-231 and human peripheral blood mononuclear cells exposed to {sup 60}Co at single fraction

Energy Technology Data Exchange (ETDEWEB)

Andrade, Lidia Maria; Campos, Tarcisio Passos Ribeiro de [Universidade Federal de Minas Gerais, Belo Horizonte, MG (Brazil). Dept. de Engenharia Nuclear]. E-mail: lidia.andrade@unifenas.br; Leite, M.F. [Universidade Federal de Minas Gerais, Belo Horizonte, MG (Brazil). Dept. de Fisiologia e Biofisica; Goes, A.M. [Universidade Federal de Minas Gerais, Belo Horizonte, MG (Brazil). Dept. de Bioquimica e Imunologia

2005-10-15

Radiotherapy using gamma rays is a common modality of breast cancer treatment. The aim of this research is to investigate the biological response of the human breast cancer cell line MDAMB-231 and human peripheral blood mononuclear cells (PBMC) exposed in vitro to {sup 60} Co irradiation at a single fraction of 10 Gy, 25 Gy and 50 Gy doses at 136,4 cGy.min{sup -1} rate. Cells were irradiated at room temperature by the Theratron 80 radiotherapy system. Biological response was evaluated through cellular viability using MTT assay and nucleus damages visualized by Propidium Iodide assay and electrophoresis agarose gel after gamma irradiation. Nucleus damages induced by {sup 60} Co irradiation were compared to damage caused by cell exposure to 10% methanol. The 50 Gy dose of irradiation did not stimulate nucleus damages at the same level as that affected by 10% methanol induction in the MDAMB-231. Further studies are necessary to understand these mechanisms in the MDAMB-231 human breast carcinoma cell line.(author)

Absorbed dose modeled for a liquid circulating around a Co-60 irradiator

International Nuclear Information System (INIS)

Mangussi, J.

2013-01-01

A model for the distribution of the absorbed dose in a volume of liquid circulating into an active tank containing a Co-60 irradiator is presented. The absorbed dose, the stir process and the liquid recirculation into the active tank are modeled. The absorbed dose for different fractions of the volume is calculated. The necessary irradiation times for the achievement of the required absorbed dose are evaluated. (author)

Molecular Basis for Enhancement of the Meiotic DMCI Recombinase by RAD51AP1

Energy Technology Data Exchange (ETDEWEB)

Dray, Eloise; Dunlop, Myun Hwa; Kauppi, Liisa; San Filippo, Joseph San; Wiese, Claudia; Tsai, Miaw-Sheue; Begovic, Sead; Schild, David; Jasin, Maria; Keeney, Scott; Sung, Patrick

2010-11-05

Homologous recombination is needed for meiotic chromosome segregation, genome maintenance, and tumor suppression. RAD51AP1 (RAD51 Associated Protein 1) has been shown to interact with and enhance the recombinase activity of RAD51. Accordingly, genetic ablation of RAD51AP1 leads to enhanced sensitivity to and also chromosome aberrations upon DNA damage, demonstrating a role for RAD51AP1 in mitotic homologous recombination. Here we show physical association of RAD51AP1 with the meiosis-specific recombinase DMC1 and a stimulatory effect of RAD51AP1 on the DMC1-mediated D-loop reaction. Mechanistic studies have revealed that RAD51AP1 enhances the ability of the DMC1 presynaptic filament to capture the duplex DNA partner and to assemble the synaptic complex, in which the recombining DNA strands are homologously aligned. We also provide evidence that functional co-operation is dependent on complex formation between DMC1 and RAD51AP1, and that distinct epitopes in RAD51AP1 mediate interactions with RAD51 and DMC1. Finally, we show that RAD51AP1 is expressed in mouse testes, and that RAD51AP1 foci co-localize with a subset of DMC1 foci in spermatocytes. These results suggest that RAD51AP1 also serves an important role in meiotic homologous recombination.

Chromosome aberration yields in human lymphocytes induced by fractionated doses of x-radiation

International Nuclear Information System (INIS)

Purrott, R.J.; Reeder, E.

1976-01-01

Unstimulated (G 0 ) human peripheral blood lymphocytes were exposed at 37degC to doses of 200 or 500 rad of X-rays delivered in two equal fractions. The dose fractions were separated by intervals of up to 7 h in the 200 rad study and up to 48 h for 500 rad. In both studies the mean levels of dicentrics and total unstable aberrations began to decline when fractions were delivered with intervals of greater than 2 h. With 200 rad the yield had decreased to an additive baseline (i.e. equal to only twice the yield of a single 100-rad fraction) by an interval of 4 h. Following 500 rad the yield declined until 8 h and then remained 20% above the expected additive baseline even when 48 h separated the fractions. Possible explanations for this discrepancy are discussed. In a second experiment PHA stimulated lymphocyte cultures were exposed to 2 doses of 125 rad of X-rays up to 7 h apart in an attempt to demonstrate the late peak in aberration yield originally reported by Lane. Control cultures received unsplit doses of 250 rad at the time of the corresponding second 125-rad fraction. No evidence of a late peak in dicentric yield was observed. The yield remained approximately the same irrespective of the time interval between fractions but these split dose yields were significantly different from the accompanying unsplit controls

The influence of whole body 60Co-irradiation on distribution of 67Ga in tumor-bearing mice

International Nuclear Information System (INIS)

Wakao, Hiromi; Shimura, Akira; Higashi, Tomomitsu

1981-01-01

Since the initial findings that 67 Ga has a preferential affinity for soft tissue tumors, in humans numerous suggestions have been advanced for the basic mechanism involved. The effects produced by whole-body X-irradiation on the excretion and tissue distribution of 67 Ga have been reported by Swartzendruber and others. Bradley and coworkers have shown that these irradiation effects were associated with an increase in serum iron. The present investigation was undertaken in order to study the relationships between the change in the serum iron concentration and 67 Ga accumulation in the tumor and soft tissues in mice bearing Ehrlich's ascites tumor. The following results were obtained. (1) The serum iron concentration was significantly decreased between 3 and 6 hours after 10 Gy (1,000 rad) dose of whole-body 60 Co-irradiation. Subsequently, the serum iron levels were slowly elevated. (2) The uptake of 67 Ga in the tumor and soft tissues was increased if the serum iron concentration was decreased by whole-body 60 Co-irradiation during the early phase. On the contrary, if the serum iron concentration was high, the uptake of 67 Ga in the tumor was decreased. (3) The excretion of 67 Ga from the body was delayed if the serum iron concentration was decreased by whole-body 60 Co-irradiation. However, if the serum iron concentration was high, the excretion of 67 Ga from the body significantly increased. (author)

Effects of 60Co gamma-ray local irradiation on rat liver on alkaline phosphatase, lactate dehydrogenase and catalase in the liver and serum

International Nuclear Information System (INIS)

Hishikawa-Itoh, Youko; Ayakawa, Yoshio; Miyata, Nobuki

1980-01-01

Rats were given a single exposure of various doses (0, 5, 50, 500, and 5000 rads) to local irradiation of 60 Co γ-ray on liver. Activities of alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and catalase in the serum and liver were measured at various time intervals after irradiation. These results were summarized as follows; 1. ALP activity in the serum had no effect on irradiation up to 500 rads, but in the case of 5000 rads irradiation exhibited a marked loss from 4 days after irradiation. ALP activity in the liver to 5000 rads exposure on 7 days after irradiation increased, on the other hand in the serum decreased, and the patterns of ALP activities in the liver and serum to the irradiation doses were opposite. 2. LDH activity in the serum by exposure to 5, 500 and 5000 rads increased at 4 days after irradiation, but at 7 days significantly decreased. LDH activity in the liver to the irradiation doses on 7 days after irradiation did not markedly change, but in the serum it tended to be low in inverse proportion to the irradiation doses. 3. Catalase activity in the serum to 50 and 500 rads exposure increased at 4 days after irradiation and decreased at 7 days, but to 5000 rads exposure it decreased in the course of time. Catalase activity in the liver and serum on 7 days after irradiation were inversely proportional to irradiation doses. It is difficult that catalase activity makes a index of clinical irradiation effects, because catalase activity decrease under the various conditions, such as cancer, anemia, infection of bacterias and so on. Since activities of ALP and LDH increase in almost disease, decrease of ALP activity and decrease following temporary increase of LDH activity by irradiation may be able to become a clinical indicator on irradiation effects. (author)

Sorption of {sup 60} Co on inorganic solids; Sorcion de {sup 60} Co en solidos inorganicos

Energy Technology Data Exchange (ETDEWEB)

Granados C, F.; Bulbulian G, S. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico); Mardel V, B. [UAM-I, 09340 Mexico D.F. (Mexico)

2003-07-01

The behavior of sorption of the {sup 60} Co in aqueous solution under static conditions to different values of pH of the aqueous solution (1, 3, 5, 7, and 10) on MgO, MnO{sub 2}, SnO, TiO{sub 2}, activated carbon and calcinate hydrotalcite was investigated. It was found that the best sorbents of the {sup 60} Co was the MnO{sub 2}, activated carbon and TiO{sub 2} whose sorption was incremented when increasing the pH value of the aqueous solutions, in the one case of the hydrated oxides, the {sup 60} Co interacted with the electrically charged surface of the sorbents that depends on the pH of the solution and of the point of zero charge (zpc) of the sorbent. (Author)

Hybridization Capture Using RAD Probes (hyRAD, a New Tool for Performing Genomic Analyses on Collection Specimens.

Directory of Open Access Journals (Sweden)

Tomasz Suchan

Full Text Available In the recent years, many protocols aimed at reproducibly sequencing reduced-genome subsets in non-model organisms have been published. Among them, RAD-sequencing is one of the most widely used. It relies on digesting DNA with specific restriction enzymes and performing size selection on the resulting fragments. Despite its acknowledged utility, this method is of limited use with degraded DNA samples, such as those isolated from museum specimens, as these samples are less likely to harbor fragments long enough to comprise two restriction sites making possible ligation of the adapter sequences (in the case of double-digest RAD or performing size selection of the resulting fragments (in the case of single-digest RAD. Here, we address these limitations by presenting a novel method called hybridization RAD (hyRAD. In this approach, biotinylated RAD fragments, covering a random fraction of the genome, are used as baits for capturing homologous fragments from genomic shotgun sequencing libraries. This simple and cost-effective approach allows sequencing of orthologous loci even from highly degraded DNA samples, opening new avenues of research in the field of museum genomics. Not relying on the restriction site presence, it improves among-sample loci coverage. In a trial study, hyRAD allowed us to obtain a large set of orthologous loci from fresh and museum samples from a non-model butterfly species, with a high proportion of single nucleotide polymorphisms present in all eight analyzed specimens, including 58-year-old museum samples. The utility of the method was further validated using 49 museum and fresh samples of a Palearctic grasshopper species for which the spatial genetic structure was previously assessed using mtDNA amplicons. The application of the method is eventually discussed in a wider context. As it does not rely on the restriction site presence, it is therefore not sensitive to among-sample loci polymorphisms in the restriction sites

Effect of dose fractionation of 60Co gamma radiation on longevity and reproduction of Sitophilus granarius (L., 1785) (Col., Curculionidae) in wheat

International Nuclear Information System (INIS)

Arthur, V.; Walder, J.M.M.; Wiendl, F.M.; Domarco, R.E.; Haddad, S.S.

1987-01-01

The effects of fractionated doses of gamma radiation in different interval of time on longevity and reproductivity of Sitophilus granarius (L., 1785) are studied. Gamma radiation was provided at dose rate of 1.56 kGy/hour by a Cobalt 60 source (Gammabeam-650). The insects were divided in two sets: one was irradiated at acute doses and the other in fractionated doses, with interval of 48 hours. Both sets received doses of 0,40, 50, 60, 70, 80, 90 and 100Gy. Mortality and and emergency were determined weekly. (M.A.C.) [pt

Characterization of iminothiosulfine-type ions [HNCS 2] rad +/ rad - and their neutral counterparts by mass spectrometry and computational chemistry

Science.gov (United States)

Vivekananda, S.; Raghunath, P.; Bhanuprakash, K.; Srinivas, R.; Trikoupis, Moschoula A.; Terlouw, Johan K.

2000-12-01

Electron ionization of rhodanine yields iminothiosulfine ions H- N C- S- Srad + , 1brad + , which readily communicate with the higher energy cyclic isomer H- N CS2rad + , 1arad + . CBS-QB3 and G AUSSIAN-2 model chemistries predict that one electron reduction reverses the stability order but that the (singlet) neutrals remain connected via a negligible energy barrier. Neutralization-reionization (NR) experiments demonstrate that singlet 1a and its heterocumulene isomer 1b are stable species in the gas-phase. However, the co-generated triplet species readily dissociate into 3S2rad + + HNC. Confirmatory experimental evidence comes from charge reversal (CR) and NR experiments on the cyclic anion H- N CS2rad - , 1arad - .

Preferential binding of yeast Rad4-Rad23 complex to damaged DNA

International Nuclear Information System (INIS)

Jansen, L.E.T.; Verhage, R.A.; Brouwer, J.

1998-01-01

The yeast Rad4 and Rad23 proteins form a complex that is involved in nucleotide excision repair (NER). Their function in this process is not known yet, but genetic data suggest that they act in an early step in NER. We have purified an epitope-tagged Rad4.Rad23 (tRad4. Rad23) complex from yeast cells, using a clone overproducing Rad4 with a hemagglutinin-tag at its C terminus. tRad4.Rad23 complex purified by both conventional and immuno-affinity chromatography complements the in vitro repair defect of rad4 and rad23 mutant extracts, demonstrating that these proteins are functional in NER. Using electrophoretic mobility shift assays, we show preferential binding of the tRad4.Rad23 complex to damaged DNA in vitro. UV-irradiated, as well as N-acetoxy-2-(acetylamino)fluorene-treated DNA, is efficiently bound by the protein complex. These data suggest that Rad4.Rad23 interacts with DNA damage during NER and may play a role in recognition of the damage

CO2 Monitoring and Background Mole Fraction at Zhongshan Station, Antarctica

Directory of Open Access Journals (Sweden)

Yulong Sun

2014-09-01

Full Text Available Background CO2 mole fraction and seasonal variations, measured at Zhongshan station, Antarctica, for 2010 through 2013, exhibit the expected lowest mole fraction in March with a peak in November. Irrespective of wind direction, the mole fraction of CO2 distributes evenly after polluted air from station operations is removed from the data sets. The daily range of average CO2 mole fraction in all four seasons is small. The monthly mean CO2 mole fraction at Zhongshan station is similar to that of other stations in Antarctica, with seasonal CO2 amplitudes in the order of 384–392 µmol∙mol−1. The annual increase in recent years is about 2 µmol∙mol−1∙yr−1. There is no appreciable difference between CO2 mole fractions around the coast of Antarctica and in the interior, showing that CO2 observed in Antarctica has been fully mixed in the atmosphere as it moves from the north through the southern hemisphere.

Significance of fractionation regimens in radiation and combined hyperthermia using a murine fibrosarcoma

International Nuclear Information System (INIS)

Hahn, E.W.; Alfieri, A.A.; Kim, J.H.

1978-01-01

The significance of time--dose ralationships in the use of local tumor hyperthermia (LTH) when combined with radiation (RAD) was studied in a murine fibrosarcoma. RAD, either alone or combined with LTH, was delivered in four equal fractions (total doses, 1.8 to 4.2 krad) separated by 1 to 4 days. LTH (43.1 C +- .05 C for 15 minutes, water bath) was applied immediately after RAD. In this tumor system, RAD was most effective when delivered every 2nd or 3rd day, by a factor of 1.25 over the response achieved when the four fractions were delivered every 1 or 4 days. At all levels studied, RAD + LTH produced a superior tumor response compared to RAD alone. The ratio of the RAD + LTH/RAD doses to achieve an isobiological response ranged from 1.7 to 2.5. Most significant was the finding that the RAD + LTH treatment response was independent of the fractionation scheme used and more dependent on the total RAD dose delivered

Repair of pyrimidine dimers in radiation-sensitive mutants rad3, rad4, rad6, and rad9 of Saccharomyces cerevisiae. [nicking

Energy Technology Data Exchange (ETDEWEB)

Prakash, L [Rochester Univ., N.Y. (USA). Dept. of Radiation Biology and Biophysics; Rochester Univ., N.Y. (USA). School of Medicine and Dentistry)

1977-10-01

The ability to remove ultraviolet-induced pyrimidine dimers was examined in four radiation-sensitive mutants of Saccharomyces cerevisiae. The susceptibility of DNA from irradiated cells to nicking by either the T4 uv-endonuclease or an endonuclease activity found in crude extracts of Micrococcus luteus was used to measure the presence of dimers in DNA. The rad3 and rad4 mutants are shown to be defective in dimer excision whereas the rad6 and rad9 mutants are proficient in dimer excision.

Case of radiation gastroduodenitis caused by /sup 60/Co-irradiation therapy for hepatoma

Energy Technology Data Exchange (ETDEWEB)

Nishikawa, H; Hayashi, N; Morise, K; Tunekawa, J; Kaneshiro, K [Nagoya Univ. (Japan). Faculty of Medicine

1981-02-01

A 56-year-old man with hepatoma, who had been treated with total 3,960 rad of /sup 60/Co-irradiation 2 months previously, was readmitted to the hospital because of fever and anemia. Following admission, he passed tarry stools every day. Barium meal examination revealed esophageal varices and erosive gastritis of the antrum. At endoscopy, many hemorrhagic erosions were found in the gastric antrum and the first part of duodenum, which were located in the irradiation area. Since repeated blood transfusion failed to improve anemia, a complete fasting with intravenous hyperalimentation and antacid therapy were started. Two months later, feeding was started and thereafter continued without any appreciable GI bleeding or worsening of anemia. Endoscopic examination at this time revealed only a few erosions scattered over the edematous antral mucosa as well as the proximal duodenum. IVH, antacids and abstinence from food seem to be an effective measure in the treatment of radiation injury of the gut.

Cloning of an E. coli RecA and yeast RAD51 homolog, radA, an allele of the uvsC in Aspergillus nidulans and its mutator effects.

Science.gov (United States)

Seong, K Y; Chae, S K; Kang, H S

1997-04-30

An E. coli RecA and yeast RAD51 homolog from Aspergillus nidulans, radA, has been cloned by screening genomic and cDNA libraries with a PCR-amplified probe. This probe was generated using primers carrying the conserved sequences of eukaryotic RecA homologs. The deduced amino acid sequence revealed two conserved Walker-A and -B type nucleotide-binding domains and exhibited 88%, 60%, and 53% identity with Mei-3 of Neurospora crassa, rhp51+ of Schizosaccharomyces pombe, and Rad51 of Saccharomyces cerevisiae, respectively. radA null mutants constructed by replacing the whole coding region with a selection marker showed high methyl methanesulfonate (MMS) sensitivity. Heterozygous diploids of radA disruptant with the uvsC114 mutant failed to complement with respect to MMS-sensitivity, indicating that radA is an allele of uvsC. In selecting spontaneous forward selenate resistant mutations, mutator effects were observed in radA null mutants similarly to those shown in uvsC114 mutant strains.

Experimental studies on the late change of preoperative irradiation ( 60Co) following colonic anastomosis

International Nuclear Information System (INIS)

Ieda, Katsuyuki; Katsumi, Masaharu; Matsumoto, Kohichi

1982-01-01

We irradiated single dose of 1000 rad (equivalent to fractioned dose of 2000 - 2500 rad for the human) to the lower abdomen of four mongrel dogs. One week after irradiation, we operated on them and performed colonic transection using an auto-suture instrument. We investigated whether the preoperative irradiation would disturb the colonic anastomosis or not, in a long-term observation. All the dogs appeared to be suffered from slight radiation proctitis after irradiation. But their symptoms gradually subsided. Two of them lost an appetite gradually and died on the fifth and sixth month after operation. We examined them macroscopically and microscopically on the third, fifth, sixth and eighth month after operation, respectively. We could not find any gross radiation injuries on the anastomoses and the other organs. The mucosa and submucosa proved microsopically well healed. Muscle layers did not adhered layer to layer because of auto-suture stapler. We could not find inflammatory cell infiltration nor excessive fibrosis. Therefore, we speculate that preoperative irradiation of single dose of 1000 rad does not affect the wound healingF of the colonic anastomoses, neither bring about the late change. (author)

Sorption of 60 Co on inorganic solids

International Nuclear Information System (INIS)

Granados C, F.; Bulbulian G, S.; Mardel V, B.

2003-01-01

The behavior of sorption of the 60 Co in aqueous solution under static conditions to different values of pH of the aqueous solution (1, 3, 5, 7, and 10) on MgO, MnO 2 , SnO, TiO 2 , activated carbon and calcinate hydrotalcite was investigated. It was found that the best sorbents of the 60 Co was the MnO 2 , activated carbon and TiO 2 whose sorption was incremented when increasing the pH value of the aqueous solutions, in the one case of the hydrated oxides, the 60 Co interacted with the electrically charged surface of the sorbents that depends on the pH of the solution and of the point of zero charge (zpc) of the sorbent. (Author)

Lower energy and pulse stacking. A safer alternative for skin tightening using fractional CO2 laser.

Science.gov (United States)

Motta, Marcos Matias; Stelini, Rafael Fantelli; Calderoni, Davi Reis; Gilioli, Rovilson; Kharmandayan, Paulo

2016-01-01

To evaluate the effect of different energies and stacking in skin shrinkage. Three decreasing settings of a fractional CO2 laser were applied to the abdomen of Twenty five Wistar rats divided into three groups. Group I (n=5) was histologically evaluated for microthermal zones dimensions. Groups II and III (n=10 each) were macroscopic evaluated with freeware ImageJ for area contraction immediately and after 30 and 60 days. No statistical significance was found within microthermal zone histological dimensions (Group I) in all settings studied. (Ablation depth: 76.90 to 97.18µm; Coagulation depth: 186.01 to 219.84 µm). In Group II, macroscopic evaluation showed that all settings cause significant immediate skin contraction. The highest setting cause significant more intense tightening effect initially, contracting skin area from 258.65 to 179.09 mm2. The same pattern was observed in Group III. At 30 and 60 days, the lowest setting significantly sustained contraction. Lower fractional CO2 laser energies associated to pulse stacking could cause consistent and long lasting tissue contraction in rats.

Fractional CO2 laser resurfacing for atrophic acne scars

DEFF Research Database (Denmark)

Hedelund, Lene; Haak, Christina Skovbølling; Togsverd-Bo, Katrine

2012-01-01

The treatment of acne scars with fractional CO(2) lasers is gaining increasing impact, but has so far not been compared side-by-side to untreated control skin.......The treatment of acne scars with fractional CO(2) lasers is gaining increasing impact, but has so far not been compared side-by-side to untreated control skin....

Transfer of 60Co from midwater squid to sperm whales

International Nuclear Information System (INIS)

Umezu, Takeshi; Minamisako, Yoko; Ebihara, Hiroshi; Watanabe, Hiroshi.

1984-01-01

Sperm whales are notable squid-eaters. They feed mainly on medium to large-sized cephalopods at midwater levels and defecate near the surface. This suggests the existence of an upward transport of 60 Co by sperm whales from the mesopelagic zone (150-1,200m). To elucidate this squid-whale route for this artificial radionuclide, 60 Co content was determined in squid and in predator whales captured by commercial whaling. In the Cephalopoda livers 60 Co levels of 30-500 mBq kg -1 wet were found and in the viscera of Odontoceti (toothed whales) 15-40 mBq kg -1 wet. About 0.3% of 60 Co ingested was estimated to be retained in a 23-year-old male sperm whale. In the livers of Bryde's whales, 60 Co levels of 40-80 mBq kg -1 wet were detected, but not in euphausiids and sardines, their possible prey. The level of Co in sperm whales was nearly the same as in Bryde's whales. Specific radioactivity 60 Co/ 59 Co in mBq μg -1 was several times higher in sperm whale (1.1-1.6) than in cephalopods (0.19-0.77). Eating prey with a high content of 60 Co in the 1960's may have contributed to the present body burden in sperm whales with a long-life span. However, the origin of 60 Co in Bryde's whales is unknown. (author)

Studies on the transportation dynamics of 60Co in simulated ecosystem

International Nuclear Information System (INIS)

Wei Jianpeng; Chen Chuanqun; Wang Shouxiang; Sun Zhiming; Wang Jiyan

1999-12-01

The isotope tracer techniques were applied to study the transportation, accumulation and distribution of 60 Co in the pot-cultivated tomato-soil, aquatic and terrestrial ecosystems. Based on the principle of tracer dynamic compartment models, the mathematical formulae were established via computer simulation to describe the 60 Co behavior patterns in ecosystems and thus provided some basic information for elucidating the behavior of 60 Co in the environment. The results are as follows: (1) When 60 Co was introduced into the tomato-soil system, 60 Co was transported and accumulated in the soil and adsorbed by tomato root quickly, then transported to the above-ground plant. (2) The behavior patterns of 60 Co in the tomato-soil system could be described using the opened two-compartment model. (3) When 60 Co was introduced into aquatic system in the form of 60 Co-CoCl 2 , it was transported and transformed via deposit, complexation with other ions, adsorption and absorption by aquatic living things and led to the distribution and accumulation in individual part of the living things. (4) The behavior pattern of 60 Co in the aquatic-terrestrial ecosystem could be described by using opened five-compartment model

Synergistic interactions between RAD5, RAD16, and RAD54, three partially homologous yeast DNA repair genes each in a different repair pathway

International Nuclear Information System (INIS)

Glassner, B.J.; Mortimer, R.K.

1994-01-01

Considerable homology has recently been noted between the proteins encoded by the RAD5, RAD16 and RAD54 genes of Saccharomyces cerevisiae. These genes are members of the RAD6, RAD3 and RAD50 epistasis groups, respectively, which correspond to the three major DNA repair pathways in yeast. These proteins also share homology with other eucaryotic proteins, including those encoded by SNF2 and MO1 of yeast, brahma and lodestar of Drosophila and the human ERCC6 gene. The homology shares features with known helicases, suggesting a newly identified helicase subfamily. We have constructed a series of congenic single-, double- and triple-deletion mutants involving RAD5, RAD16 and RAD54 to examine the interactions between these genes. Each deletion mutation alone has only a moderate effect on survival after exposure to UV radiation. Each pairwise-double mutant exhibits marked synergism. The triple-deletion mutant displays further synergism. These results confirm the assignment of the RAD54 gene to the RAD50 epistasis group and suggest that the RAD16 gene plays a larger role in DNA repair after exposure to UV radiation than has been suggested previously. Additionally, the proteins encoded by RAD5, RAD16, and RAD54 may compete for the same substrate after damage induced by UV radiation, possibly at an early step in their respective pathways. 49 refs., 6 figs., 2 tabs

Co-60 uptake in some young cereal plants

International Nuclear Information System (INIS)

Dumitru, R.O.

1998-01-01

The measure of Co-60 uptake by young cereal plants is dependent on the type of soil, plant and growth conditions. Depending on the size of the uptake, a plant can be used for industrial purposes, fodder, foodstuff or for possible decontamination of the soil. Although the requirement for cobalt in higher plants is little, their contamination with Co-60 can be of interest because this radionuclide belongs to the class of the radionuclides with a great radiotoxicity. The soil-to-plant transfer factor (TF) is a measure of the radionuclide uptake in the plant. In this paper the soil-to-plant TFs for Co-60 were determined for the whole aerial part of some young plants in the cereal class that, in this stage of the development, may be used as fodder. To determine soil-to-plant TFs, plants cultivated in pots in laboratory conditions were used. The method used is similar with the plantlet method of Neubauer and Schneider. We have determined some physical, chemical and mineralogical properties of the studied soil, a brown-reddish forest type soil. The soil-to-plant TFs were calculated on the basis of the Co-60 activities determined in plant and soil dried samples. For the vegetal samples the whole aerial part of the plants was measured in millet, wheat, barley and triticale. At harvest, only a few millet plants where flowered. The results of the measurements of soil-to-plant TFs of Co-60 are the following: 0.0315±0.0017 for millet, 0.0260±0.0014 for barley, 0.0140±0.0008 for wheat and 0.0491±0.0022 for triticale. These TFs were corrected for standard conditions and were compared with data from literature. The soil-to-plant TFs for Co-60 found in the aerial part of young cereals are close to those recommended for the fodder. The obtained values prove the strong dependence of the soil-to-plant TFs for Co-60 on the type of soil and plant. (author)

Feasibility study on production of Co-60 in PHWR

Energy Technology Data Exchange (ETDEWEB)

Park, Kyung Bae; Han, Hyon Soo; Joo, Po Kook

2000-05-01

The purpose of this study is to analyze the safeties and the economics for Co-60 production from Wolsung PHWR and to verify the feasibility on the manufacturing of the final Co-60 source for industrial irradiation. The feasibility of reactor conversion was carried out with KEPCO collaboration. Through the site survey on the experience of Gentililly-2 in Canada, a feasibility of plant conversion, changes in design, equipment and tools for Co-60 production was verified. It was estimated that the reactor conversion would not impose adverse impact on plant safety. For the encapsulation of radiation source and storage of the final products, a modification of concrete hot cell at KAERI was primary concerns. The installation and improvement of facilities are needed to avoid cross contamination and extra radiation exposure. Main items for these are pressure gauge, separated HEPA filter the ceiling separation, extra-shielding and ceiling hoist system. At present, storage pool has got admission based on 400 kCi. But it is necessary to seismic analysis and design improvement of shielding to store 10 MCi (Co-60) which is the estimated Co-60 capacity produced by 3 PHWRs. According to present investigation, a production of Co-60 by PHWR and RIPE was seemed to be an economically feasible business and it was also expected that a joint venture will be able to realize by cooperation with MDS Nordion Co.

Feasibility study on production of Co-60 in PHWR

International Nuclear Information System (INIS)

Park, Kyung Bae; Han, Hyon Soo; Joo, Po Kook

2000-05-01

The purpose of this study is to analyze the safeties and the economics for Co-60 production from Wolsung PHWR and to verify the feasibility on the manufacturing of the final Co-60 source for industrial irradiation. The feasibility of reactor conversion was carried out with KEPCO collaboration. Through the site survey on the experience of Gentililly-2 in Canada, a feasibility of plant conversion, changes in design, equipment and tools for Co-60 production was verified. It was estimated that the reactor conversion would not impose adverse impact on plant safety. For the encapsulation of radiation source and storage of the final products, a modification of concrete hot cell at KAERI was primary concerns. The installation and improvement of facilities are needed to avoid cross contamination and extra radiation exposure. Main items for these are pressure gauge, separated HEPA filter the ceiling separation, extra-shielding and ceiling hoist system. At present, storage pool has got admission based on 400 kCi. But it is necessary to seismic analysis and design improvement of shielding to store 10 MCi (Co-60) which is the estimated Co-60 capacity produced by 3 PHWRs. According to present investigation, a production of Co-60 by PHWR and RIPE was seemed to be an economically feasible business and it was also expected that a joint venture will be able to realize by cooperation with MDS Nordion Co

Lung density change after SABR: A comparative study between tri-Co-60 magnetic resonance-guided system and linear accelerator.

Science.gov (United States)

Kim, Eunji; Wu, Hong-Gyun; Park, Jong Min; Kim, Jung-In; Kim, Hak Jae; Kang, Hyun-Cheol

2018-01-01

Radiation-induced lung damage is an important treatment-related toxicity after lung stereotactic ablative radiotherapy (SABR). After implementing a tri-60Co magnetic-resonance image guided system, ViewRayTM, we compared the associated early radiological lung density changes to those associated with a linear accelerator (LINAC). Eight patients treated with the tri-60Co system were matched 1:1 with patients treated with LINAC. Prescription doses were 52 Gy or 60 Gy in four fractions, and lung dose-volumetric parameters were calculated from each planning system. The first two follow-up computed tomography (CT) were co-registered with the planning CT through deformable registration software, and lung density was measured by isodose levels. Tumor size was matched between the two groups, but the planning target volume of LINAC was larger than that of the tri-60Co system (p = 0.036). With regard to clinically relevant dose-volumetric parameters in the lungs, the ipsilateral lung mean dose, V10Gy and V20Gy were significantly poorer in tri-60Co plans compared to LINAC plans (p = 0.012, 0.036, and 0.017, respectively). Increased lung density was not observed in the first follow-up scan compared to the planning scan. A significant change of lung density was shown in the second follow-up scan and there was no meaningful difference between the tri-60Co system and LINAC for all dose regions. In addition, no patient developed clinical radiation pneumonitis until the second follow-up scan. Therefore, there was no significant difference in the early radiological lung damage between the tri-60Co system and LINAC for lung SABR despite of the inferior plan quality of the tri-60Co system compared to that of LINAC. Further studies with a longer follow-up period are needed to confirm our findings.

Activation measurements for thermal neutrons. Part A. Cobalt (60Co) activation

International Nuclear Information System (INIS)

Kerr, George D.; Shizuma, Kiyoshi; Endo, Satoru; Maruyama, Takashi; Cullings, Harry M.; Komura, Kazuhisa; Okumura, Yutaka; Egbert, Stephen D.

2005-01-01

The 60 Co measurements at Hiroshima and Nagasaki were reviewed and compared with the results of the new DS02 calculations for the two cities. Some corrections were made to previously published data from the 1965 measurements of JNIRS, ground ranges of all of the 60 Co measurements were reviewed and new ground ranges were determined when possible by transforming sample coordinates to the new city maps for Hiroshima and Nagasaki, and transmission factors were investigated for a number of samples used in the 60 Co measurements. Transmission factors were not calculated for all samples used in the 60 Co measurements but some general rules were given for estimating transmission factors for these samples. Experimental measurements of the background 60 Co activity from environmental neutrons were also reviewed, and it was found that the 60 Co background from environmental neutrons was not an important factor in the 60 Co measurements of bomb-induced activity at either city. (J.P.N.)

Influence of beta radiation from tritium and gamma radiation from 60Co on the biological half-times of organically bound tritium

International Nuclear Information System (INIS)

Radwan, I.

1981-01-01

The influence of beta radiation from tritium on the biological half-times of organically bound tritium in particular tissues of the rat is compred with the influence of fractionated gamma radiation from 60 Co. (M.F.W.)

In vitro response of the human breast cancer cell line MDAMB-231 and human peripheral blood mononuclear cells exposed to 60Co at single fraction

Directory of Open Access Journals (Sweden)

Lídia Maria Andrade

2005-10-01

Full Text Available Radiotherapy using gamma rays is a common modality of breast cancer treatment. The aim of this research is to investigate the biological response of the human breast cancer cell line MDAMB-231 and human peripheral blood mononuclear cells (PBMC exposed in vitro to 60 Co irradiation at a single fraction of 10 Gy, 25 Gy and 50 Gy doses at 136,4 cGy.min-1 rate. Cells were irradiated at room temperature by the Theratron 80 radiotherapy system. Biological response was evaluated through cellular viability using MTT assay and nucleus damages visualized by Propidium Iodide assay and electrophoresis agarose gel after gamma irradiation. Nucleus damages induced by 60Co irradiation were compared to damage caused by cell exposure to 10% methanol. The 50 Gy dose of irradiation did not stimulate nuclus damages at the same level as that affected by 10% methanol induction in the MDAMB-231. Further studies are necessary to understand these mechanisms in the MDAMB-231 human breast carcinoma cell line.Radioterapia utilizando radiação gama é uma modalidade comum no tratamento do câncer de mama. A proposta deste estudo é investigar a resposta biológica in vitro da linhagem celular MDAMB-231 de câncer de mama humano e células do sangue periférico humano (PBMC expostas à irradiação pelo Co60 em frações simples de 10Gy, 25Gy e 50Gy e 136,4cGy min-1 rate. As células foram irradiadas a temperatura ambiente usando o equipamento de radioterapia Theratron 80 radiotherapy system. A resposta biológica, após irradiação gama, foi avaliada através do ensaio do MTT para viabilidade celular e o do ensaio com Iodeto de Propídio para visualização do dano nuclear, além da eletroforese em gel de agarose. Os danos nucleares induzidos pelo Co60 foram comparados aos danos causados pela exposição das células à solução de metanol a 10%. Nós observamos que a dose de 50Gy não estimulou a mesma quantidade de danos nucleares que a solução de metanol a 10% nas c

RAD51AP2, a novel vertebrate- and meiotic-specific protein, sharesa conserved RAD51-interacting C-terminal domain with RAD51AP1/PIR51

Energy Technology Data Exchange (ETDEWEB)

Kovalenko, Oleg V.; Wiese, Claudia; Schild, David

2006-07-25

Many interacting proteins regulate and/or assist the activities of RAD51, a recombinase which plays a critical role in both DNA repair and meiotic recombination. Yeast two-hybrid screening of a human testis cDNA library revealed a new protein, RAD51AP2 (RAD51 Associated Protein 2), that interacts strongly with RAD51. A full-length cDNA clone predicts a novel vertebrate specific protein of 1159 residues, and the RAD51AP2 transcript was observed only in meiotic tissue (i.e. adult testis and fetal ovary), suggesting a meiotic-specific function for RAD51AP2. In HEK293 cells the interaction of RAD51 with an ectopically-expressed recombinant large fragment of RAD51AP2 requires the C-terminal 57 residues of RAD51AP2. This RAD51-binding region shows 81% homology to the C-terminus of RAD51AP1/PIR51, an otherwise totally unrelated RAD51-binding partner that is ubiquitously expressed. Analyses using truncations and point mutations in both RAD51AP1 and RAD51AP2 demonstrate that these proteins use the same structural motif for RAD51 binding. RAD54 shares some homology with this RAD51-binding motif, but this homologous region plays only an accessory role to the adjacent main RAD51-interacting region, which has been narrowed here to 40 amino acids. A novel protein, RAD51AP2, has been discovered that interacts with RAD51 through a C-terminal motif also present in RAD51AP1.

Targeting Rad50 sensitizes human nasopharyngeal carcinoma cells to radiotherapy

International Nuclear Information System (INIS)

Chang, Lihong; Huang, Jiancong; Wang, Kai; Li, Jingjia; Yan, Ruicheng; Zhu, Ling; Ye, Jin; Wu, Xifu; Zhuang, Shimin; Li, Daqing; Zhang, Gehua

2016-01-01

The Mre11-Rad50-Nbs1 (MRN) complex is well known for its crucial role in initiating DNA double strand breaks (DSBs) repair pathways to resistant irradiation (IR) injury and thus facilitating radioresistance which severely reduces radiocurability of nasopharyngeal cancer (NPC). Targeting native cellular MRN function would sensitize NPC cells to IR. A recombinant adenovirus containing a mutant Rad50 gene (Ad-RAD50) expressing Rad50 zinc hook domain but lacking the ATPase domain and the Mre11 interaction domain was constructed to disrupt native cellular MRN functions. The effects of Ad-RAD50 on the MRN functions were assessed in NPC cells lines using western blot, co-immunoprecipitation and confocal microscopy analyses. The increased radiosensitivity of transient Ad-RAD50 to IR was examined in NPC cells, including MTT assay, colony formation. The molecular mechanisms of radiosensitization were confirmed by neutral comet assay and western bolts. Nude mice subcutaneous injection, tumor growth curve and TUNEL assay were used to evaluate tumor regression and apoptosis in vivo. Rad50 is remarkably upregulated in NPC cells after IR, implying the critical role of Rad50 in MRN functions. The transient expression of this mutant Rad50 decreased the levels of native cellular Rad50, Mre11 and Nbs1, weakened the interactions among these proteins, abrogated the G2/M arrest induced by DSBs and reduced the DNA repair ability in NPC cells. A combination of IR and mutant RAD50 therapy produced significant tumor cytotoxicity in vitro, with a corresponding increase in DNA damage, prevented proliferation and cell viability. Furthermore, Ad-RAD50 sensitized NPC cells to IR by causing dramatic tumor regression and inducing apoptosis in vivo. Our findings define a novel therapeutic approach to NPC radiosensitization via targeted native cellular Rad50 disruption. The online version of this article (doi:10.1186/s12885-016-2190-8) contains supplementary material, which is available to

Defective thymine dimer excision in radiation-sensitive mutants rad10 and rad16 of Saccharomyces cerevisiae

Energy Technology Data Exchange (ETDEWEB)

Prakash, L [Rochester Univ., N.Y. (USA). School of Medicine and Dentistry

1977-04-01

Two rad mutants of yeast, rad10 and rad16, are shown to be defective in the removal of UV-induced pyrimidine dimers since DNAs obtained from irradiated cells following a post-irradiation incubation in the dark still retain UV-endonuclease-sensitive sites. Both rad10 and rad16 mutants are in the same pathway of excision-repair as the rad1, rad2, rad3, and rad4 mutants.

Modeling of 60Co transport by groundwater

International Nuclear Information System (INIS)

Serebryakov, B.E.; Ivanov, E.A.; Shchukin, A.P.

2006-01-01

Results of calculation of the 60 Co migration in a water-bearing horizon after the accident Novo-Voronezh NPP in 1985 are presented. The accident was connected with the liquid radioactive waste leakage into the ground water. The features of 60 Co migration in the water-bearing horizon and its coming into the Don river are calculated by means of three-dimensional models. Population irradiation estimations show that the accident did not lead to exceeding the recommended dose limits [ru

Comparative analysis of 60Co intensity-modulated radiation therapy

International Nuclear Information System (INIS)

Fox, Christopher; Romeijn, H Edwin; Lynch, Bart; Dempsey, James F; Men, Chunhua; Aleman, Dionne M

2008-01-01

In this study, we perform a scientific comparative analysis of using 60 Co beams in intensity-modulated radiation therapy (IMRT). In particular, we evaluate the treatment plan quality obtained with (i) 6 MV, 18 MV and 60 Co IMRT; (ii) different numbers of static multileaf collimator (MLC) delivered 60 Co beams and (iii) a helical tomotherapy 60 Co beam geometry. We employ a convex fluence map optimization (FMO) model, which allows for the comparison of plan quality between different beam energies and configurations for a given case. A total of 25 clinical patient cases that each contain volumetric CT studies, primary and secondary delineated targets, and contoured structures were studied: 5 head-and-neck (H and N), 5 prostate, 5 central nervous system (CNS), 5 breast and 5 lung cases. The DICOM plan data were anonymized and exported to the University of Florida optimized radiation therapy (UFORT) treatment planning system. The FMO problem was solved for each case for 5-71 equidistant beams as well as a helical geometry for H and N, prostate, CNS and lung cases, and for 3-7 equidistant beams in the upper hemisphere for breast cases, all with 6 MV, 18 MV and 60 Co dose models. In all cases, 95% of the target volumes received at least the prescribed dose with clinical sparing criteria for critical organs being met for all structures that were not wholly or partially contained within the target volume. Improvements in critical organ sparing were found with an increasing number of equidistant 60 Co beams, yet were marginal above 9 beams for H and N, prostate, CNS and lung. Breast cases produced similar plans for 3-7 beams. A helical 60 Co beam geometry achieved similar plan quality as static plans with 11 equidistant 60 Co beams. Furthermore, 18 MV plans were initially found not to provide the same target coverage as 6 MV and 60 Co plans; however, adjusting the trade-offs in the optimization model allowed equivalent target coverage for 18 MV. For plans with comparable

Smoking: the influence of carboxyhemoglobin (HbCO) on tumor oxygenation and response to radiation

International Nuclear Information System (INIS)

Siemann, D.W.; Hill, R.P.; Bush, R.S.

1978-01-01

The effectiveness of localized x radiation on the transplantable KHT sarcoma was studied in nonanesthetized C3H mice possessing blood carboxyhemoglobin (HbCO) levels similar to those observed in heavy smokers. HbCO values of 10 percent were induced in tumor-bearing animals, either acutely just prior to irradiation or chronically during tumor growth and irradiation, by allowing the mice to breathe gas mixtures containing carbon monoxide (CO) in air. Tumors were irradiated either with single doses of 1500, 2000, or 2500 rad or with seven 500 rad fractions given at 24 hr intervals. Tumor cell survival was determined using an in vivo lung colony or an in vitro agar colony assay. The results with single doses of radiation indicate that under conditions of both acute and chronic exposure, the presence of 10 percent HbCO in the blood of the mice at the time of irradiation increases the survival of tumor cells in the hypoxic region of the survival curve by a factor of 2. During the fractionated irradiation, tumor cell survival in the presence of a 10 percent blood HbCO level (induced either acutely or chronically) was found to be significantly higher than that observed in air breathing mice. The results indicate that HbCO levels, such as are observed in heavy smokers, result in a larger fraction of hypoxic tumor cells. These findings suggest that heavy smoking prior to treatment may worsen the prognosis of patients undergoing radiotherapy

Evaluation of Radiosensitivity of HeLa Cells Infected with Polio Virus Irradiated by Co 60

Directory of Open Access Journals (Sweden)

F Seif

2008-04-01

Full Text Available ABSTRACT: Introduction & Objective: The main purpose of radiotherapy is exposing enough doses of radiation to tumor tissue and protecting the normal tissues around it. Tumor dose for each session in radiotherapy will be considered based on radiosensitivity of the tissues. The presence of viral diseases in tumoral area can affect the radiosensitivity of cells. This study aimed to evaluate the radiosensitivity of Hela cells infected with poliomyelitis virus irradiated by Co 60. Materials & Methods: In this study, the radiosensitivity of HeLa cells, with or without the viral infection, after gamma radiation of cobalt 60, was assessed. Results: Results of comparison of the radisensitivity of infected and uninfected cells indicates that after 2 Gy irradiation by Co 60, polio infection in low, moderate and high virus load, increases the cell death by 20-30%, 30-40% and 70-90% respectively. Conclusion : Radiosensitivity of tumoral cells increase when they are infected with viral agents. Results of this study showed that non cancer diseases should be considered when prescribing dose fraction in radiotherapy of cancers.

Characterization of new radiation-sensitive mutant, Escherichia coli K-12 radC102

International Nuclear Information System (INIS)

Felzenszwalb, I.; Sargentini, N.J.; Smith, K.C.

1984-01-01

A new radiation-sensitive mutant, radC, has been isolated. The radC gene is located at 81.0 min on the Escherichia coli K-12 linkage map. The radC mutation sensitized cells to uv radiation, but unlike most DNA repair mutations, sensitization to X rays was observed only for rich medium-grown cells. For cells grown in rich medium, the radC mutant was normal for γ radiation mutagenesis, but showed less uv-radiation mutagenesis than the wild-type strain; it showed normal amount of X- and uv-radiation-induced DNA degradation, and it wasapprox. =60% deficient in recombination ability. The radC strain was normal for host cell reactivation of γ and uv-irradiated bacteriophage the radC mutation did not sensitize a recA strain, but did sensitize a radA and a polA strain to X and uv radiation and a uvrA strain to uv radiation. Therefore, it is suggested that the radC gene product plays a role in the growth medium-dependent, recA gene-dependent repair of DNA single-strand breaks after X irradiation, and in postreplication repair after uv irradiation

Roles for the yeast RAD18 and RAD52 DNA repair genes in UV mutagenesis.

Science.gov (United States)

Armstrong, J D; Chadee, D N; Kunz, B A

1994-11-01

Experimental evidence indicates that although the Saccharomyces cerevisiae RAD18 and RAD52 genes are not required for nucleotide excision repair, they function in the processing of UV-induced DNA damage in yeast. Conflicting statements regarding the UV mutability of strains deleted for RAD18 prompted us to re-examine the influence of RAD18, and RAD52, on UV mutagenesis. To do so, we characterized mutations induced by UV in SUP4-o, a yeast suppressor tRNA gene. SUP4-o was maintained on a plasmid in isogenic strains that either carried one of two different rad18 deletions (rad18 delta) or had RAD52 disrupted. Both rad18 deletions decreased the frequency of UV-induced SUP4-o mutations to levels close to those for spontaneous mutagenesis in the rad18 delta backgrounds, and prevented a net increase in mutant yield. A detailed analysis of mutations isolated after UV irradiation of one of the rad18 delta strains uncovered little evidence of the specificity features typical for UV mutagenesis in the isogenic repair-proficient (RAD) parent (e.g., predominance of G.C-->A.T transitions). Evidently, UV induction of SUP4-o mutations is highly dependent on the RAD18 gene. Compared to the RAD strain, disruption of RAD52 reduced the frequency and yield of UV mutagenesis by about two-thirds. Closer inspection revealed that 80% of this reduction was due to a decrease in the frequency of G.C-->A.T transitions. In addition, there were differences in the distributions and site specificities of single base-pair substitutions. Thus, RAD52 also participates in UV mutagenesis of a plasmid-borne gene in yeast, but to a lesser extent than RAD18.

Recovery of deficient homologous recombination in Brca2-depleted mouse cells by wild-type Rad51 expression.

Science.gov (United States)

Lee, Shauna A; Roques, Céline; Magwood, Alissa C; Masson, Jean-Yves; Baker, Mark D

2009-02-01

The BRCA2 tumor suppressor is important in maintaining genomic stability. BRCA2 is proposed to control the availability, cellular localization and DNA binding activity of the central homologous recombination protein, RAD51, with loss of BRCA2 resulting in defective homologous recombination. Nevertheless, the roles of BRCA2 in regulating RAD51 and how other proteins implicated in RAD51 regulation, such as RAD52 and RAD54 function relative to BRCA2 is not known. In this study, we tested whether defective homologous recombination in Brca2-depleted mouse hybridoma cells could be rectified by expression of mouse Rad51 or the Rad51-interacting mouse proteins, Rad52 and Rad54. In the Brca2-depleted cells, defective homologous recombination can be restored by over-expression of wild-type mouse Rad51, but not mouse Rad52 or Rad54. Correction of the homologous recombination defect requires Rad51 ATPase activity. A sizeable fraction ( approximately 50%) of over-expressed wild-type Rad51 is nuclear localized. The restoration of homologous recombination in the presence of a low (i.e., non-functional) level of Brca2 by wild-type Rad51 over-expression is unexpected. We suggest that Rad51 may access the nuclear compartment in a Brca2-independent manner and when Rad51 is over-expressed, the normal requirement for Brca2 control over Rad51 function in homologous recombination is dispensable. Our studies support loss of Rad51 function as a critical underlying factor in the homologous recombination defect in the Brca2-depleted cells.

60Co-labeling in 59Co(n,γ)60Co reaction and γ-ray irradiation of [Co(dien)2]3+ and [Co(en)3]3+ in crystals and/or in polyvinyl alcohol

International Nuclear Information System (INIS)

Sasaki, K.; Iiyoshi, N.; Watanabe, J.; Yamatera, H.

1982-01-01

Three isomers (sym-fac, unsym-fac, and mer forms) of [Co(dien) 2 ]Cl 3 were irradiated in a reactor in the form of crystals and in amorphous solids, where the ions were dissolved in polyvinyl alcohol (PVA) or adsorbed on an SP-Sephadex ion exchanger. The distribution of produced 60 Co among the isomers of the Co(III) complex and the Co(II) species was determined. The preferential labeling on the parent isomer was observed in crystals but not in PVA. In the Sephadex, no marked labeling occurred. For comparison with reactor-irradiated samples, mixed solutions of [Co(dien) 2 ]Cl 3 and 60 Co-labeled cobalt (II) chloride dissolved in PVA films ([Co(III)]/[Co(II)] = 2 - 3) were irradiated by γ-rays. Significant labeling was observed after the irradiation. Comparison of the results from the above experiments showed that the labeling was enhanced by radiation chemical reactions, and that the preferential labeling on the parent isomer of crystal samples resulted from the stiffness of the crystal matrix. (orig.)

The development of 60Co γ knife therapy sources

International Nuclear Information System (INIS)

Wu Rihua; Li Xingyi; Wu Guihua; Xia Bing; Zhang Jirong; Chen Tieguang

2001-01-01

60 Co γ gamma knife source is a kernel unit of γ knife therapy equipment. It has small active core, high specific activity, narrow half dark area, best focus form, long use period. The research of 60 Co γ knife sources are presented. Specifications of γ knife sources, technical parameters, safety performance, structure feature, procedure and quality control during research are discussed. 60 Co γ source consists of high specific activity cobalt pellets and double stainless steel sealed by argon arc welding. Its safety performance, surface contamination and leakage testing meet the requirements of GB 4075 and GB 4076

Concentration of 60Co by marine organisms through sediments

International Nuclear Information System (INIS)

Nakahara, Motokazu; Koyanagi, Taku; Saiki, Masamichi

1976-01-01

Uptake of 60 Co absorbed on sea sands by benthic marine organisms was observed in laboratory experiments, since the radioactive cobalt released from nuclear power plants or other establishments into coastal seawater trends to be absorbed on sea sediments and also various kinds of marine organisms live in bottom sediments. Few kinds of flatfishes (Limanda spp.) and shrimp (Trachypenaeus curvirostris) were reared in aquariums contained seawater and sea sands which were highly contaminated with 60 Co previously, and whole body retention and distribution of radioactivity were measured on the organisms taken up from the aquariums occasionally by a scintillation counter. Uptake of 60 Co from ingested sea sands was also observed on the flatfishes administrating the contaminated sands orally. Concentration of 60 Co by the flatfishes reared in the sands was not significant while the shrimp showed high retention of the radioactivity. The food habit of shrimp which usually feeds on organic detritus with other small benthic organisms is different from that of flatfishes, one of the carnivorous, and considered to bring the difference on the pathway of radionuclides concentration. Assimilation of 60 Co via the digestive tract of flatfishes through the sands was estimated as about 10 per cent of the administrated radioactivity. (auth.)

Decommissioning of a 60Co unit and estimation of personal doses

International Nuclear Information System (INIS)

Lin, H.; Lin, P.; Liu, T.; Chu, C.

2003-01-01

Chang-hua Christian hospital needs to uninstall the 60 Co unit. The mode of this 60 Co teletherapy unit is SHIMADZU RTGS-10. The original lead head was taken as the source container of this 60 Co unit. The source head was dismantled and put into the prepared wooden box, after the source was sealed. This study describes the planning and dismantling of the retirement and transport of the 60 Co unit, and personal doses measured during the procedure. This work estimates the doses of radiation received by exposed workers during the dismantling of the machine. The workers received doses of approximately 53 μSv. This study shows that the original lead head can be used as the source container of this 60 Co unit. The 60 Co machine was smoothly dismantled and transported by conscientious and careful workers, using planned and controlled radiation protection, following the ALARA (as low as reasonably achievable) rule. (author)

Protective effect of the LevRad on treat of paracoccidioidomycosis

International Nuclear Information System (INIS)

Martins, Estefania M.N.; Andrade, Antero S.R.; Fernandes, Viviane Cristina; Morais, Elis Araujo; Goes, Alfredo M.; Resende, Maria Aparecida de

2011-01-01

Paracoccidioides brasiliensis is the agent of Paracoccidioidomycosis (PCM), the most prevalent deep mycosis of Latin America. The period of treat depend on the chemotherapeutic and the severity of disease and its administration not ensure the complete destruction of the fungus. The search for new alternatives is necessary. The aim of this study was to evaluate the protective effect of yeast cells of P. brasiliensis attenuated by gamma irradiation (LevRad) on therapeutic vaccination of BALB/c. The therapeutic potential of LevRad with or without fluconazole was assessed for the first time, intraperitoneally, in BALB/c, 60 days after intratracheal infection with a highly virulent non-irradiated P.brasiliensis isolate. The animals were divided in five experimental groups: uninfected (C-), infected (C+), infected treated with fluconazole (Inmed), infected treated with LevRad (InRad) and infected treated with fluconazole + LevRad (InRadMed). The organs (lungs, spleen and liver) were collected to analyze CFU (colony forming units) and histology. The sera were used to evaluate the immunization efficacy, and to assess IgG subtypes (IgG1, IgG2a, IgG2b, IgG3) and total IgG levels. There was significant decrease in the CFU counts of the lungs of InMed, InRadMed and InRad. No were visualized histopathological alterations in the organs of these groups, except in InRad there was granulomatous lesions unifocal, little and discrete. The levels of IgG and its subtypes IgG2a, IgG2b increased, probably due to the increase of cytokines that promote switching to these isotypes. These preliminary results can provide new prospect for immunotherapy of PCM, but it will be necessary new studies to evaluate administration dose and period treatment. (author)

C60 as an Atom Trap to Capture Co Adatoms

DEFF Research Database (Denmark)

Yang, Peng; Li, Dongzhe; Repain, Vincent

2015-01-01

C60 molecules were used to trap Co adatoms and clusters on a Au(111) surface using atomic/molecular manipulation with a scanning tunneling microscope. Two manipulation pathways (successive integration of single Co atoms in one molecule or direct integration of a Co cluster) were found...... to efficiently allow the formation of complexes mixing a C60 molecule with Co atoms. Scanning tunneling spectroscopy reveals the robustness of the pi states of C60 that are preserved after Co trapping. Scanning tunneling microscopy images and density functional theory calculations reveal that dissociated Co...... clusters of up to nine atoms can be formed at the molecule-substrate interface. These results open new perspectives in the interactions between metal adatoms and molecules, for applications in metal-organic devices...

Effect of Co-60 irradiation on hyperimmune antimeningococcus globulins-gamma

International Nuclear Information System (INIS)

Galguera, M.; Le Riverand, E.; Padron, S.

1990-01-01

Globulins-gamma from voluntary blood donors immunized with the Cuban BC antimeningococcus vaccine is now being used in our country for the treatment of the meningococcus disease. This study of the effect of Co-60 irradiation on antimeningococcus globulins-gamma was carried out to try to eliminate the inconvenience shown by the traditionally used sterilization procedures (losses in the filter and persistence of viral contamination). globulins-gamma was obtained by ethanol fractionation and was irradiated at a different dose in solution with different stabilizers and it was also lyophilized. Results of the chemical controls carried out lead to the conclusion that it is possible to use radiosterilization on this product in a lyophilized form. The preservation of bactericidal activity, even after the highest irradiation doses, confirms the above mentioned. 13 refs

MRI for the assessment of malignancy in BI-RADS 4 mammographic microcalcifications.

Directory of Open Access Journals (Sweden)

Barbara Bennani-Baiti

Full Text Available Assess the performance of breast MRI to diagnose breast cancer in BI-RADS 4 microcalcifications detected by mammography.This retrospective, IRB-approved study included 248 consecutive contrast-enhanced breast MRI (1.5T, protocol in accordance with EUSOBI recommendations performed to further diagnose BI-RADS 4 microcalcifications detected at mammography during a 3-year period. Standard of reference had to be established by histopathology. Routine consensus reading results by two radiologists were dichotomized as positive or negative and compared with the reference standard (benign vs malignant to calculate diagnostic parameters.There were 107 malignant and 141 benign microcalcifications. Malignancy rates were 18.3% (23/126 BI-RADS 4a, 41.7% (25/60 BI-RADS 4b and 95% (59/62 BI-RADS 4c. There were 103 true-positive, 116 true-negative, 25 false-positive, and 4 false-negative (one invasive cancer, three DCIS; 2 BI-RADS 4c, 1 BI-RADS 4b on mammography breast MRI findings, effecting a sensitivity, specificity, PPV, and NPV of 96.3% (95%-CI 90.7-99.0%, 82.3% (95%-CI 75.0-88.2%, 80.5% (95%-CI 72.5-87.0% and 96.7% (95%-CI 91.7-99.1%, respectively.MRI is an accurate tool to further diagnose BI-RADS 4a and 4b microcalcifications and may be helpful to avoid unnecessary biopsies in BI-RADS 4a and 4b lesions. BI-RADS 4c microcalcifications should be biopsied irrespective of MRI findings.

Quality of tri-Co-60 MR-IGRT treatment plans in comparison with VMAT treatment plans for spine SABR.

Science.gov (United States)

Choi, Chang Heon; Park, So-Yeon; Kim, Jung-In; Kim, Jin Ho; Kim, Kyubo; Carlson, Joel; Park, Jong Min

2017-02-01

To investigate the plan quality of tri-Co-60 intensity-modulated radiation therapy (IMRT) plans for spine stereotactic ablative radiotherapy (SABR). A total of 20 patients with spine metastasis were retrospectively selected. For each patient, a tri-Co-60 IMRT plan and a volumetric-modulated arc therapy (VMAT) plan were generated. The spinal cords were defined based on MR images for the tri-Co-60 IMRT, while isotropic 1-mm margins were added to the spinal cords for the VMAT plans. The VMAT plans were generated with 10-MV flattening filter-free photon beams of TrueBeam STx ™ (Varian Medical Systems, Palo Alto, CA), while the tri-Co-60 IMRT plans were generated with the ViewRay ™ system (ViewRay inc., Cleveland, OH). The initial prescription dose was 18 Gy (1 fraction). If the tolerance dose of the spinal cord was not met, the prescription dose was reduced until the spinal cord tolerance dose was satisfied. The mean dose to the target volumes, conformity index and homogeneity index of the VMAT and tri-Co-60 IMRT were 17.8 ± 0.8 vs 13.7 ± 3.9 Gy, 0.85 ± 0.20 vs 1.58 ± 1.29 and 0.09 ± 0.04 vs 0.24 ± 0.19, respectively. The integral doses and beam-on times were 16,570 ± 1768 vs 22,087 ± 2.986 Gy cm 3 and 3.95 ± 1.13 vs 48.82 ± 10.44 min, respectively. The tri-Co-60 IMRT seems inappropriate for spine SABR compared with VMAT. Advances in knowledge: For spine SABR, the tri-Co-60 IMRT is inappropriate owing to the large penumbra, large leaf width and low dose rate of the ViewRay system.

Promotion of Homologous Recombination and Genomic Stability byRAD51AP1 via RAD51 Recombinase Enhancement

Energy Technology Data Exchange (ETDEWEB)

Wiese, Claudia; Dray, Eloise; Groesser, Torsten; San Filippo,Joseph; Shi, Idina; Collins, David W.; Tsai, Miaw-Sheue; Williams,Gareth; Rydberg, Bjorn; Sung, Patrick; Schild, David

2007-04-11

Homologous recombination (HR) repairs chromosome damage and is indispensable for tumor suppression in humans. RAD51 mediates the DNA strand pairing step in HR. RAD51AP1 (RAD51 Associated Protein 1) is a RAD51-interacting protein whose function has remained elusive. Knockdown of RAD51AP1 in human cells by RNA interference engenders sensitivity to different types of genotoxic stress. Moreover, RAD51AP1-depleted cells are impaired for the recombinational repair of a DNA double-strand break and exhibit chromatid breaks both spontaneously and upon DNA damaging treatment. Purified RAD51AP1 binds dsDNA and RAD51, and it greatly stimulates the RAD51-mediated D-loop reaction. Biochemical and cytological results show that RAD51AP1 functions at a step subsequent to the assembly of the RAD51-ssDNA nucleoprotein filament. Our findings provide the first evidence that RAD51AP1 helps maintain genomic integrity via RAD51 recombinase enhancement.

Total body irradiation in bone marrow transplantation: the influence of fractionation and delay of marrow infusion

International Nuclear Information System (INIS)

Lichter, A.S.; Tracy, D.; Lam, W.C.; Order, S.E.

1980-01-01

Bone marrow transplantation (BMT) after total body irradiation (TBI) and cyclophosphamide is being employed increasingly in the therapy of end stage leukemia. Interstitial pneumonitis (IP) represents a major acute toxicity after allogeneic transplantation. A more rapid reconstitution of lymphoid organs and bone marrow post transplant may result in increased immune competence and hence fewer opportunistic pulmonary infections and IP. By delaying the infusion of marrow to 72 hr after TBI (1250 rad at 7.5 rad/min) instead of the customary 24 hr, we can demonstrate an increase in initial repopulation of thymus, spleen and bone marrow, with syngeneic transplants in Lewis rats. Interstitial pneumonitis may also be caused, in part, by the pulmonary toxicity of large single exposures of TBI. Clinical and laboratory data suggest that fractionated TBI may be less toxic to the lung. When fractionated TBI (625 rad x 2, 7.5 rad/min) is compared to single dose TBI (1250 rad, 7.5 rad/min), and increased initial repopulation of lymphoid organs is observed when fractionated therapy is employed. Delay in marrow infusion and fractionation of TBI exposure may have clinical advantages in patients who receive BMT

Investigation of Chitosan for Decorporation of 60Co in the Rat

International Nuclear Information System (INIS)

Levitskaia, Tatiana G.; Creim, Jeffrey A.; Curry, Terry L.; Luders, Teresa; Morris, James E.; Sinkov, Sergey I.; Woodstock, Angela D.; Thrall, Karla D.

2009-01-01

Purpose: The reported investigation is a part of our on-going research aimed at identifying effective in vivo non-toxic decorporation agents and developing new therapies to treat internal contamination with radionuclides. The non-toxic nature of chitosan makes it an especially attractive candidate for unsupervised treatment of the general population in case of radiological/nuclear emergency. In this study, chemically unmodified water-soluble chitosan oligosaccharide of low molecular weight was tested for decorporation of cobalt-60 (Co-60) using a rodent model. Methods: Affinity of chitosan oligosaccharide for Co(II) was tested in vitro under conditions of physiological pH range and ionic strength using combined spectrophotometric and potentiometric titration techniques. Fisher F344 rat model was used for in vivo studies. To evaluate effect of chitosan on ingested Co-60, animals received single oral dose of Co-60 chloride (7-13.2 kBq per animal) followed by oral administration of chitosan material (288-366 mg per kg body weight); chitosan dosing was repeated in 24 hours. Chitosan was also tested for removal of internalized Co-60. In this study, Co-60 single intravenous injection (7-8 kBq per animal) was followed by repetitive oral (300 mg per kg body weight) or intravenous (195 mg per kg body weight) administration of the chitosan material once daily for 5 days. Control animal groups received a single dose of Co-60 without chelator treatment. Excreta was collected daily. Tissues were collected postmortem and analyzed for radioactivity by gamma counting technique. Results: In vitro experiments confirmed binding of Co(II) by chitosan oligosaccharide, formation of mixed cobalt-chitosan-hydroxide complex species was proposed, and stability constants was calculated. Control in vivo studies indicated that about 71% of ingested Co-60 was excreted in two days predominantly through the gastrointestinal tract. For intravenously administered Co-60, urinal excretion was

Simulating 60 Co gamma irradiation systems

International Nuclear Information System (INIS)

Omi, Nelson M.; Rela, Paulo R.

2000-01-01

The use of Cadgamma, a software dedicated to simulate 60 Co gamma irradiation systems, can lead to an optimized process and simulating, in a few hours, many configurations setups for the irradiation elements. The software can also simulate changes in the path of the product and the influence of any steady body like the support of the product support and source shoulders. These simulations minimize the number of dose mapping tests in industrial applications and allow the study of unusual setups. Cadgamma was developed at IPEN to simulate it is multipurpose 60 Co irradiation system, under construction and planned to be operating by the second half of 2001. The software was used on project stage and will help to optimize the irradiation process for each product to be treated. (author)

Dosimetric properties of the pocket alarm dosimeter type Alnor RAD 21L, RAD 21H, RAD 22

International Nuclear Information System (INIS)

Hauser, M.; Burgkhardt, B.; Piesch, E.

1981-02-01

In personnel monitoring pocket dosimeters with build-in alarm devices are increasingly in use. The report presents results of a test performed at Karlsruhe for the pocket dose and alarm meter type Alnor RAD 21L, RAD 21H, RAD 22. The properties investigated are above all linearity and reproducibility of the dose reading as well as of the acoustic alarm indication, dependence of the dose reading on the photon energy, the direction of the radiation incidence, the dose rate, the temperature, operational characteristic of the batteries. (orig.) [de

Soil properties related to 60Co bioavailability in tropical soils

International Nuclear Information System (INIS)

Bartoly, Flavia; Wasserman, Maria Angelica; Rochedo, Elaine Ruas Rodriguez; Viana, Aline Gonzalez; Souza, Rodrigo Camara; Oliveira, Giselle Rodrigues; Reis, Wagner Goncalves Soares; Perez, Daniel Vidal

2005-01-01

This work presents the results of field experiments to obtain soil to plants Transfer factor (TF) for 60 Co in reference plants cultivated in Ferralsol, Acrisol and Nitisol. These soils represent the majority of Brazilian agricultural area. Values of TF varied from 0.001 to 0.05 for corn and from 0.001 to 0.81 for cabbage. Results of 60 Co TF were discussed in relation to the physical and chemical properties of the soils and 60 Co geochemical partition. The sequential chemical extraction showed that more than 40% of the 60 Co present in the soils are associated to manganese oxides. These results will provide regional values for parameters used in the environmental radiological modeling aiming to optimize the planning of emergency interventions or the waste management related to tropical soils. (author)

Dosimetric evaluation of Radiotherapy units wit {sup 60}Co; Evaluacion dosimetrica de unidades de radioterapia con {sup 60}Co

Energy Technology Data Exchange (ETDEWEB)

Leon, B. Salinas de; Tovar M, V.; Becerril V, A. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

2000-07-01

The SSDL network of the IAEA performs, every year, quality audit tests for radiotherapy services ({sup 60} Co units and linear accelerators), and for national SSDL as well. Because of the SSDL-Mexico results in these tests and due to our enthusiasm and confidence in our work, a parallel test has been done , which is described in this talk as well as the results. Nowadays, a second parallel test goes up, which could confirm our optimism and open the possibility to our country to start a national dosimetric audit of {sup 60} Co radiotherapy units. (Author)

Technical Note: Comparison of peripheral patient dose from MR-guided 60 Co therapy and 6 MV linear accelerator IGRT.

Science.gov (United States)

Hauri, Pascal; Hälg, Roger A; Schneider, Uwe

2017-07-01

The use of X-ray imaging in radiation therapy can give a substantial dose to the patient. A Cobalt machine combined with an magnetic resonance imaging (MRI) was recently introduced to clinical work. One positive aspect of using non-ionizing imaging devices is the reduction of the patient exposure. The purpose of this study was to quantify the difference in out-of-field dose to the patient between the image guided radiation therapy (IGRT) treatment applied with a linear accelerator with cone beam CT (CBCT) equipment and a Cobalt machine combined with an MRI. The treatment of a rhabdomyosarcoma in the prostate was planned and irradiated using different modalities and radiation therapy machines. The whole-body dose was measured for a 3D-conformal radiation therapy (3DCRT), an intensity-modulated radiation therapy (IMRT), and a volumetric-modulated arc therapy plan applied with a conventional linear accelerator operated at 6 MV beam energy. Additionally, the dose of an IMRT plan applied with a 60 Co machine combined with an MRI was measured. Furthermore, the dose of one CBCT scan using the linear accelerator's on-board imaging system was determined. The 3D dose measurements were performed in an anthropomorphic phantom containing 168 slots for thermoluminescence dosimeters (TLDs). A combination of LiF:Mg,Ti (TLD100) and LiF:Mg,Cu,P (TLD100H) was used to accurately determine the in- and out-of-field dose. The plans were rescaled to different fractionation schemes (2 Gy, 3 Gy, and 5 Gy fraction dose) and the dose of one CBCT scan was additionally added to the treatment dose per fraction applied with the linear accelerator. The resulting absorbed doses per fraction of the two machines were compared. In the target region, all measured treatment plans presented the same magnitude of dose, while the CBCT dose was a factor of 100 smaller. Close to the planned target volume (PTV), the dose from the 60 Co machine was a factor of two higher compared with the 3DCRT + CBCT dose. Up

Radiation therapy of malignant melanomas: an evaluation of clinically used fractionation schemes

International Nuclear Information System (INIS)

Strauss, A.; Dritschilo, A.; Nathanson, L.; Piro, A.J.

1981-01-01

To assess the importance of radiation dose fraction size in the treatment of malignant melanomas, the records of 48 patients (83 sites) treated at Tufts-New England Medical Center from 1971 to 1979 have been retrospectively reviewed. During this period, the dose fractionation schemes evolved from standard fraction size to large-dose techniques. Radiation fraction size was observed to be the major factor in the clinical response of melanoma. Fractions of 600-800 rad resulted in the best overall response (80%). The rapid fractionation scheme of 800-400-400 rad on successive days resulted in intermediate response (58%) and may be useful for the palliative treatment of selected patients

Bioaccumulation and elimination of 60 Co and 137 Cs by Anomalocardia brasiliana (Gmelin, 1791) (Mollusca bivalvia). Remobilization of 60 Co, retained in marine sediment by microbial activity

International Nuclear Information System (INIS)

Mayr, L.M.

1984-05-01

It was studied the capacity of a bi valve mollusc Anomalocardia brasiliana, which lives in the local bottom sediment, to remobilize 60 Co previously sorbed in the sediment. Laboratory experiments demonstrated that the transference of 60 Co from the sediment to the animal was insignificant (bioaccumulation factor (BF) of the order of 10 -3 ). At the same time, the capacity of microorganisms, present in the bottom sediment, to remobilize 60 Co was studied. The results showed that this via of transference was important, considering the much greater microorganism biomass in relation to the biomass of bentonic organisms, as a whole. For 137 Cs the determined BF from water to the animal was 2.2. and, as in the case of 60 Co, the soft tissues concentrated more 137 Cs than shell. Remaining viscera showed the highest BFs. In another series of experiments, the loss of 60 Co or 137 Cs, previously accumulated by A. brasiliana, was followed in aquaria with or without sediment and the respective biological half-lives were calculated. Soft tissues retained 60 Co longer (biological half-life = 117 days) than shells, whereas for 137 Cs the opposite was observed and shells showed a biological half life of 38.5 days. The low values of 60 Co and 137 Cs BF S do not allow to classify A. brasiliana as good biological indicator for pollution by there radionuclides. However since A brasiliana is consumed by the local population and is commercialized to other areas, it was recommended that its contamination by 60 Co or 137 Cs should be monitored. (author)

The Use of Locally Applied Vibration to Minimize Pain during Fractional CO Laser Therapy in Living Liver-Donor Scar Management

Directory of Open Access Journals (Sweden)

Sinyoung Song

2016-11-01

Full Text Available BackgroundFractional CO2 laser is an effective treatment for scars, but most patients complain about sharp burning pain, even after the application of lidocaine ointment. This study analyzed the impact of a vibrating device to nonpharmacologically reduce the acute pain of laser treatment, in accordance with the gate control theory of pain management.MethodsThis is a prospective study performed from May 2013 through March 2014. Fifty-three patients (mean age, 26.7 years; range, 16–44 years who had donated livers for liver transplantation were treated with a fractional CO2 laser (10,600 nm; model eCO2, Lutronic Corp for their abdomen scars. Laser treatment was applied 4 months after surgery. A commercially available, locally applied vibrating device (model UM-30M, Unix Electronics Co. Ltd. was used, in an on-and-off pattern, together with the CO2 laser. A visual analogue scale (VAS; 0, no pain; 10, most severe pain of pain sensation was assessed and statistically analyzed using a paired t-test.ResultsThe average VAS score for pain with the vibrating device was 4.60 and the average VAS score without the vibrating device was 6.11. The average difference between scores was 1.51 (P=0.001.ConclusionsA locally applied vibrating device was demonstrated to be effective in reducing pain when treating with a fractional CO2 laser. Vibration treatment could be helpful when treating scars with fractional CO2 laser in pain-sensitive patients, particularly children.

CO2-dependent carbon isotope fractionation in the dinoflagellate Alexandrium tamarense

Science.gov (United States)

Wilkes, Elise B.; Carter, Susan J.; Pearson, Ann

2017-09-01

The carbon isotopic composition of marine sedimentary organic matter is used to resolve long-term histories of pCO2 based on studies indicating a CO2-dependence of photosynthetic carbon isotope fractionation (εP). It recently was proposed that the δ13C values of dinoflagellates, as recorded in fossil dinocysts, might be used as a proxy for pCO2. However, significant questions remain regarding carbon isotope fractionation in dinoflagellates and how such fractionation may impact sedimentary records throughout the Phanerozoic. Here we investigate εP as a function of CO2 concentration and growth rate in the dinoflagellate Alexandrium tamarense. Experiments were conducted in nitrate-limited chemostat cultures. Values of εP were measured on cells having growth rates (μ) of 0.14-0.35 d-1 and aqueous carbon dioxide concentrations of 10.2-63 μmol kg-1 and were found to correlate linearly with μ/[CO2(aq)] (r2 = 0.94) in accord with prior, analogous chemostat investigations with eukaryotic phytoplankton. A maximum fractionation (εf) value of 27‰ was characterized from the intercept of the experiments, representing the first value of εf determined for an algal species employing Form II RubisCO-a structurally and catalytically distinct form of the carbon-fixing enzyme. This value is larger than theoretical predictions for Form II RubisCO and not significantly different from the ∼25‰ εf values observed for taxa employing Form ID RubisCO. We also measured the carbon isotope contents of dinosterol, hexadecanoic acid, and phytol from each experiment, finding that each class of biomarker exhibits different isotopic behavior. The apparent CO2-dependence of εP values in our experiments strengthens the proposal to use dinocyst δ13C values as a pCO2 proxy. Moreover, the similarity between the εf value for A. tamarense and the consensus value of ∼25‰ indicates that the CO2-sensitivity of carbon isotope fractionation saturates at similar CO2 levels across all three

Comparative analysis of {sup 60}Co intensity-modulated radiation therapy

Energy Technology Data Exchange (ETDEWEB)

Fox, Christopher [Sun Nuclear Corporation, 425-A Pineda Court, Melbourne, FL 32940 (United States); Romeijn, H Edwin; Lynch, Bart; Dempsey, James F [Department of Radiation Oncology, University of Florida, Gainesville, FL 32610-0385 (United States); Men, Chunhua [Department of Industrial and Systems Engineering, University of Florida, Gainesville, FL 32611-6595 (United States); Aleman, Dionne M [Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario (Canada)], E-mail: chrisfox@sunnuclear.com, E-mail: romeijn@ise.ufl.edu, E-mail: lynchb@ufl.edu, E-mail: chhmen@ufl.edu, E-mail: aleman@mie.utoronto.edu, E-mail: dempsey@ufl.edu

2008-06-21

In this study, we perform a scientific comparative analysis of using {sup 60}Co beams in intensity-modulated radiation therapy (IMRT). In particular, we evaluate the treatment plan quality obtained with (i) 6 MV, 18 MV and {sup 60}Co IMRT; (ii) different numbers of static multileaf collimator (MLC) delivered {sup 60}Co beams and (iii) a helical tomotherapy {sup 60}Co beam geometry. We employ a convex fluence map optimization (FMO) model, which allows for the comparison of plan quality between different beam energies and configurations for a given case. A total of 25 clinical patient cases that each contain volumetric CT studies, primary and secondary delineated targets, and contoured structures were studied: 5 head-and-neck (H and N), 5 prostate, 5 central nervous system (CNS), 5 breast and 5 lung cases. The DICOM plan data were anonymized and exported to the University of Florida optimized radiation therapy (UFORT) treatment planning system. The FMO problem was solved for each case for 5-71 equidistant beams as well as a helical geometry for H and N, prostate, CNS and lung cases, and for 3-7 equidistant beams in the upper hemisphere for breast cases, all with 6 MV, 18 MV and {sup 60}Co dose models. In all cases, 95% of the target volumes received at least the prescribed dose with clinical sparing criteria for critical organs being met for all structures that were not wholly or partially contained within the target volume. Improvements in critical organ sparing were found with an increasing number of equidistant {sup 60}Co beams, yet were marginal above 9 beams for H and N, prostate, CNS and lung. Breast cases produced similar plans for 3-7 beams. A helical {sup 60}Co beam geometry achieved similar plan quality as static plans with 11 equidistant {sup 60}Co beams. Furthermore, 18 MV plans were initially found not to provide the same target coverage as 6 MV and {sup 60}Co plans; however, adjusting the trade-offs in the optimization model allowed equivalent target

Bioaccumulation of 137Cs and 60Co by Helianthus annuus

International Nuclear Information System (INIS)

Hornik, M.; Pipiska, M.; Vrtoch, L.; Augustin, J.; Lesny, J.

2005-01-01

The 60 Co and 137 Cs bioaccumulation by Helianthus annuus L. was measured during 9 day cultivation at 20 ± 2 o C in hydroponic Hoagland medium. Previous starvation for K + and for NH 4 + 2.2 and 2.7 times, respectively, enhanced 137 Cs uptake rate. Previous cultivation in surplus of K + ions 50 mmol·l -1 has no effect on 137 Cs bioaccumulation rate. Both 137 Cs and 60 Co bioaccumulation significantly increase with dilution of basic Hoagland medium up to 1:7 for caesium and up to 1:3 for cobalt followed by mild decrease at higher dilutions. Root to shoot specific 137 Cs radioactivity ratio (Bq.g -1 /Bq·g -1 , fresh wt.) increased with dilution from 1.46 to 9.6-9.8. The values root to shoot specific radioactivity ratio for 60 Co were less dependent on the nutrient concentrations and were within the range 5.7 to 8.5. 137 Cs was localized mainly in young leaves (30%) and roots (39%) and 60 Co mainly in roots (67%) and leaves (20%). Obtained data showed less sensitivity of 60 Co uptake by sunflower on nutrient concentration in hydroponic media. (author)

Safety protection and technical improvement of 60Co irradiation facilities

International Nuclear Information System (INIS)

Zhou Yongxing; Liang Cannan

1993-01-01

To ensure personal safety, some improvements has been made in the design of 60 Co irradiation compartment. The shielding door was interlocked while the 60 Co source to be lifted to the irradiation position or lowered to the shielded position. A universal change-over switch was used to cut the power supply when the source moved beyond the limits. Both γ-ray alarm and a closed-TV system were adopted. The electromagnetic attraction method was employed to shift the 60 Co source from the Pb container to the source pipe

Decontamination of fermented chicken feet by 60Co irradiation

International Nuclear Information System (INIS)

Gao Peng; Wang Yan; Huang Min; Wu Ling; Du Xiaoying; Lei Qing; Xie Yan

2010-01-01

Fermented chicken feet was treated by 60Co irradiation, and the aerobic plate count, enumeration of coliforms, pathogens and TBARS value were measured during storage. The results showed that, aerobic plate count of all irradiated samples was lower than control, and enumeration of coliforms, and pathogens of Staphylococcus aureus, Shigella, Salmonella were not detected. TBARS value of all treatments was stable during 60 d storage. It could be concluded that 60Co irradiation of chicken feet was an effective method to prolong its shelf life. (authors)

Variations in Mre11/Rad50/Nbs1 status and DNA damage-induced S-phase arrest in the cell lines of the NCI60 panel

Directory of Open Access Journals (Sweden)

Eastman Alan

2011-05-01

Full Text Available Abstract Background The Mre11/Rad50/Nbs1 (MRN complex is a regulator of cell cycle checkpoints and DNA repair. Defects in MRN can lead to defective S-phase arrest when cells are damaged. Such defects may elicit sensitivity to selected drugs providing a chemical synthetic lethal interaction that could be used to target therapy to tumors with these defects. The goal of this study was to identify these defects in the NCI60 panel of cell lines and identify compounds that might elicit selective cytotoxicity. Methods We screened the NCI60 panel in search of cell lines that express low levels of MRN proteins, or that fail to arrest in S-phase in response to the topisomerase I inhibitor SN38. The NCI COMPARE program was used to discover compounds that preferentially target cells with these phenotypes. Results HCT116 cells were initially identified as defective in MRN and S phase arrest. Transfection with Mre11 also elevated Rad50 and Nbs1, and rescued the defective S-phase arrest. Cells of the NCI60 panel exhibited a large range of protein expression but a strong correlation existed between Mre11, Rad50 and Nbs1 consistent with complex formation determining protein stability. Mre11 mRNA correlated best with protein level suggesting it was the primary determinant of the overall level of the complex. Three other cell lines failed to arrest in response to SN38, two of which also had low MRN. However, other cell lines with low MRN still arrested suggesting low MRN does not predict an inability to arrest. Many compounds, including a family of benzothiazoles, correlated with the failure to arrest in S phase. The activity of benzothiazoles has been attributed to metabolic activation and DNA alkylation, but we note several cell lines in which sensitivity does not correlate with metabolism. We propose that the checkpoint defect imposes an additional mechanism of sensitivity on cells. Conclusions We have identified cells with possible defects in the MRN complex

Variations in Mre11/Rad50/Nbs1 status and DNA damage-induced S-phase arrest in the cell lines of the NCI60 panel

International Nuclear Information System (INIS)

Garner, Kristen M; Eastman, Alan

2011-01-01

The Mre11/Rad50/Nbs1 (MRN) complex is a regulator of cell cycle checkpoints and DNA repair. Defects in MRN can lead to defective S-phase arrest when cells are damaged. Such defects may elicit sensitivity to selected drugs providing a chemical synthetic lethal interaction that could be used to target therapy to tumors with these defects. The goal of this study was to identify these defects in the NCI60 panel of cell lines and identify compounds that might elicit selective cytotoxicity. We screened the NCI60 panel in search of cell lines that express low levels of MRN proteins, or that fail to arrest in S-phase in response to the topisomerase I inhibitor SN38. The NCI COMPARE program was used to discover compounds that preferentially target cells with these phenotypes. HCT116 cells were initially identified as defective in MRN and S phase arrest. Transfection with Mre11 also elevated Rad50 and Nbs1, and rescued the defective S-phase arrest. Cells of the NCI60 panel exhibited a large range of protein expression but a strong correlation existed between Mre11, Rad50 and Nbs1 consistent with complex formation determining protein stability. Mre11 mRNA correlated best with protein level suggesting it was the primary determinant of the overall level of the complex. Three other cell lines failed to arrest in response to SN38, two of which also had low MRN. However, other cell lines with low MRN still arrested suggesting low MRN does not predict an inability to arrest. Many compounds, including a family of benzothiazoles, correlated with the failure to arrest in S phase. The activity of benzothiazoles has been attributed to metabolic activation and DNA alkylation, but we note several cell lines in which sensitivity does not correlate with metabolism. We propose that the checkpoint defect imposes an additional mechanism of sensitivity on cells. We have identified cells with possible defects in the MRN complex and S phase arrest, and a series of compounds that may

Experience of the irradiation method under mixed gas (95% O2 plus 5% CO2) inhalation

International Nuclear Information System (INIS)

Ikeda, Michio; Tazaki, Eio

1978-01-01

The irradiation method under mixed gas of 95% O 2 plus CO 2 inhalation at one atomosphere was discussed to improve therapeutic results, in malignant tumors which are not greatly sensitive to irradiation. Randomized study was done in each attending institute, with common protocols. As a result, no positive effect was recognized in irradiation method under mixed gas inhalation with daily dose of 200 rad and 5 fractions per week, which is widely used clinically. But when irradiation dose was increased up to 500 to 600 rad per fraction, effect of the mixed gas was remarkable. But against this, observing for years, results in irradiation under mixed gas inhalation were not always related to the improvement of the long term survival. (author)

Oxygen enhancement ratio (OER) to Neutron and Co-60 γ ray

International Nuclear Information System (INIS)

Kim, Mi Sook; Ji, Young Hoon; Lee, Yong Min; Kim Kyeoung Jung

1997-01-01

Experiments in vitro, using human cell lines was carried out in order to establish whether or not there was a difference between oxygen enhancement ratio (OER) of neutron and Co-60 γ-ray and to determine OER dependence on radiation dose. MG-63 cell line and H-460 cell line were defined as the most sensitive cell line to neutron among our laboratory holding cell lines through preliminary study. Anoxia as was produced in glove box. The box was flushed for one hour with a mixture of 5 % CO 2 in ultrapure N 2 (total oxygen concentration < 10 ppm) and irradiated with neutron and Co-60 γ-ray. Oxic condition was same as anoxic condition except being irradiated in general air condition. The lower OER was observed in neutron than in Co-60 γ-ray. The dose dependence of OER was observed in neutron and Co-60 γ-ray all. But the dose dependence of the OER is somewhat larger for Co-60 γ-ray than for neutron. In the range of 1 to 8 Gy, the OER for photon and neutron range from 1.54 to 1.94 and 1.23 to 1.26 in MG-63 cell line. In case of H-460 the OER for Co-60 γ-ray and neutron range from 1.24 to 1.60 and 1.06 to 1.07 respectively. (author). 19 refs., 5 tabs., 5 figs

Determining of leakage rate of radionuclides Co-60 and Cs-137 in real conditioning; Odredjivanje brzine procurivanja radionuklida Co-60 i Cs-137 u realnim uslovima

Energy Technology Data Exchange (ETDEWEB)

Plecas, I; Peric, A; Kostadinovic, A [Institut za Nuklearne Nauke Boris Kidric, Belgrade (Yugoslavia)

1989-07-01

In this paper, results of examination of LEAKAGE rate of radionuclides Co-60 and Cs-137 in real condition are given. Radionuclides Co-60 and Cs-137 were immobilized by cement process and conditioned in concrete containers trying to make similar scenario for repository of radioactive waste materials as in engineering trench systems. Experiments were realized with evaporator bottom concentrate (EB) from Nuclear Power Plant Krsko in which the main radionuclides are Co-60 and Cs-137. (author)

Increased interreader agreement in diagnosis of hepatocellular carcinoma using an adapted LI-RADS algorithm

Energy Technology Data Exchange (ETDEWEB)

Becker, Anton S., E-mail: anton.becker@usz.ch; Barth, Borna K.; Marquez, Paulo H.; Donati, Olivio F.; Ulbrich, Erika J.; Karlo, Christoph; Reiner, Cäcilia S.; Fischer, Michael A.

2017-01-15

Purpose: To evaluate a simplified Liver Imaging Reporting and Data System (LI-RADS) algorithm to improve interreader agreement while maintaining diagnostic performance for HCC. Materials and methods: MRI scans of 84 cirrhotic patients with 104 distinct liver observations were retrospectively selected to equivocally match each of the LI-RADS grades (LR1-5) using histopathology and imaging follow up as standard of reference. Four independent radiologists categorized all observations as benign (LR1-2) or potentially malignant (LR3-5) and determined LI-RADS based imaging features including observation size, arterial phase hyperenhancement, washout, capsule appearance and threshold growth for LR3-5 observations and timed their readouts. LR3-5 observations were categorized according to the LI-RADS v2014 algorithm and according to a modified LI-RADS (mLI-RADS) version. Diagnostic performance and Interreader agreement were determined for LI-RADS and mLI-RADS using receiver operating characteristics (ROC) and Fleiss’ and Cohen’s Kappa analysis respectively. Results: ROC analysis revealed equal diagnostic performance for LI-RADS and mLI-RADS (area under the ROC curve = 0.91). Interreader agreement was higher using mLI-RADS as compared to current LI-RADS showing an improved overall (κ = 0.53 ± 0.04 vs. 0.45 ± 0.04), and pair-wise agreement between most readers (κ range 0.44-0.62 vs. 0.35-0.60) at a reduced median evaluation time (51 vs. 62 s per observation, p < 0.0001). Conclusion: Focusing on observation size and washout criteria using a modified, stepwise LI-RADS decision tree for LR3-5 observations results in higher interobserver reliability and faster categorization while maintaining diagnostic accuracy.

Fractional CO(2) laser-assisted drug delivery

DEFF Research Database (Denmark)

Haedersdal, Merete; Sakamoto, Fernanda H; Farinelli, William A

2010-01-01

Ablative fractional resurfacing (AFR) creates vertical channels that might assist the delivery of topically applied drugs into skin. The purpose of this study was to evaluate drug delivery by CO(2) laser AFR using methyl 5-aminolevulinate (MAL), a porphyrin precursor, as a test drug....

The radiation protection environmental assesment for 60Co irradiation room

International Nuclear Information System (INIS)

Zheng Meiyang; Jin Guohua; Shen Genfang

2010-01-01

60 Co source is applied in the process such as sterilizing agricultural products in irradiation room of some Academy of Agricultural Sciences, which is very effective in agricultural applications. However, 60 Co is highly toxic, once the leak, the consequences would be disastrous. So it is necessary to summarize the radiation protection and safety evaluation of the irradiation room indoor and outdoor, to ensure the health and lives of the staff and the surrounding population. The radiation detectors monitor six points around the irradiation room. Results show that design of irradiation room of Academy of Agricultural Sciences are mostly safe and reliable, regardless of the source in working condition. And consequences also show 60 Co source in the normal operating will not put adverse effects on the surrounding environment. In addition, the outer radiation protective measures are also outlined, in view of 60 Co own identity. (authors)

60Co retention by a freshwater planktonic alga Scenedesmus obliquus

International Nuclear Information System (INIS)

Nucho, R.; Baudin, J.P.

1989-01-01

This paper presents the results of various decontamination experiments aimed at evaluating 60 Co retention by Scenedesmus obliquus, and the respective role played by absorption and adsorption in the contamination of the alga by this radionuclide. The physiological condition of cells is not involved in radiocobalt desorption, which seems to indicate that the phenomenon is of a passive nature. When the precontamination time is extended, the proportion of adsorbed 60 Co decreases, and the final percentage of radionuclide retained increases. These results are confirmed by bringing cells into contact with a strong chelating agent. The elimination of 60 Co in the presence of EDTA undergoes a sharp decrease which is correlated with the increase in the duration of the precontamination phase. The use of a weaker complexing agent, such as NaCl, leads to the hypothesis of there being 2 types of 60 Co receptor on cell membranes. (author)

Information managing in 60Co container inspection system

International Nuclear Information System (INIS)

Wu Zhifang; Gu Bohua; Zhou Liye; An Jigang; Liu Yisi

1998-01-01

The design, maintenance and realization of information managing database in 60 Co container inspection system made by INET of Tsinghua University is introduced. The technique of Open Database Connectivity (ODBC) is adopted to develop a general format database including text and graphic information. The database application is developed with Visual C ++ 5.0 programming language to run in 32-bit Windows operation system. It conforms to Client/Server model and supports network communication. It works very well in the laboratory emulator of 60 Co container inspection system

Radiation therapy of malignant melanomas: an evaluation of clinically used fractionation schemes

International Nuclear Information System (INIS)

Strauss, A.; Dritschilo, A.; Nathanson, L.; Piro, A.J.

1981-01-01

To assess the importance of radiation dose fraction size in the treatment of malignant melanomas, the records of 48 patients (83 sites) treated at Tufts-New England Medical Center from 1971 to 1979 have been retrospectively reviewed. During this period, the dose fractionation schemes evolved from standard fraction size to large-dose techniques. Radiation fraction size was observed to be the major factor in the clinical response of melanoma. Fractions of 600 to 800 rad resulted in the best overall response (80%). The rapid fractionation scheme of 800 to 400 to 400 rad on successive days resulted in intermediate response (58%) and may be useful for the palliative treatment of selected patients

Reconstruction of Co-60 Irradiation Facility No.1

International Nuclear Information System (INIS)

Nakamura, Yoshiteru; Takada, Isao; Kaneko, Hirohisa; Hirao, Toshio; Haneda, Noriyuki; Mitomo, Shouichi; Tachibana, Hiroyuki; Yoshida, Kenzou

1989-01-01

Cobalt Irradiation Facility No.1 was constructed in 1964 as the first large scale Co-60 irradiation facility equipped a deep water pool for source storage of Co-60 sources. Recently, the reconstruction of the facility was decided because the aging of various parts of the facility became remarkable and new research programs required upgradings of the facility. Important points of upgradings are as follows: A shielding capacity of the source storage and pool is increased to 55.5 PBq from 18.5 PBq. The opening in a floor of the irradiation room which is used for the source lifting in the room, is enlarged in order to utilize a large and high intensity source. Radiation resistance of the irradiation apparatus and installed equipments in the radiation room is increased for a high dose rate irradiation. Basic structure and shape of the facility building such as shielding, pool and building roof is not changed but electrical, mechanical equipments and systems are completely renewed. To increase a reliability, the irradiation apparatus and systems are also replaced with an improved and up-to-date one designed based on operation experiences of Co-60 facilities at TRCRE through many years. In addition, auxiliary equipments such as radiation monitors, manipulators, water treatment system and so on are replaced. This report presents the reconstruction of Co-60 Irradiation Facility No.1 stressing on the replacement and modification of the irradiation apparatus. (author)

Radiography of Co-60 in the lead cube castings

International Nuclear Information System (INIS)

Djoli Soembogo; Harun Al Rasyid R; Namad Sianta

2016-01-01

Radiography Co-60 on Carbon steel or Stainless steel has been widely applied, but for metal Lead has not yet been applied and has not yet widely known. Lead has a greater density than Carbon steel or Stainless steel and could muffle gamma radiation so it takes a longer exposure time. The result of its film radiography are also not as good as compared to radiography applications on carbon steel or Stainless steel. The study also applied digital radiography using isotope Co-60 sources and used Epson V700 scanner positive film for digitization results of conventional radiographic films. These radiographs using film AGFA D7 to get the contrast medium, medium sensitivity and good image quality. The purpose of radiography Co-60 on the cube castings Lead is to find indications of defective castings cube Lead and digitizing the results using conventional radiographic film with a positive film media scanner to process the data transfer and storage of digital data. Radiographic testing has been carried out using the isotope Co-60 on metal castings Lead with a single thickness of a single shadow method using positive film scanner media and isotope Co-60 with disabilities observation parameter Lead metal castings on radiographic film. Co-60 radiation time exposure is 3,500 hours for the thickness of the metal cube castings Lead 100 mm with the activity of 29 Ci and perpendicular SFD of 840 mm. Radiographic testing on metal cube castings Lead by the method of a single thickness of single image defects produce a parameter indicative for a cube of metal castings Lead of porosity level 2. The density mean of radiographic film was 2.051 and 2.046 for 5 minutes in a developer solution. The result of scanning positive film is in the form of digital radiography which allows for the transfer of digital data or computerized storage of digital data. This status is still within limits acceptable under the standards referred. (author)

Bioaccumulation and elimination of {sup 60} Co and {sup 137} Cs by Anomalocardia brasiliana (Gmelin, 1791) (Mollusca bivalvia). Remobilization of {sup 60} Co, retained in marine sediment by microbial activity; Bioacumulacao e eliminacao de {sup 60}Co e {sup 137}Cs por anomalocardia brasiliana (Gmelin, 1791) (Mollusca bivalvia). Remobilizacao de {sup 60}Co retido em sedimento marinho por atividade microbiana

Energy Technology Data Exchange (ETDEWEB)

Mayr, L M

1984-05-01

It was studied the capacity of a bi valve mollusc Anomalocardia brasiliana, which lives in the local bottom sediment, to remobilize {sup 60} Co previously sorbed in the sediment. Laboratory experiments demonstrated that the transference of {sup 60} Co from the sediment to the animal was insignificant (bioaccumulation factor (BF) of the order of 10{sup -3}). At the same time, the capacity of microorganisms, present in the bottom sediment, to remobilize {sup 60} Co was studied. The results showed that this via of transference was important, considering the much greater microorganism biomass in relation to the biomass of bentonic organisms, as a whole. For {sup 137} Cs the determined BF from water to the animal was 2.2. and, as in the case of {sup 60} Co, the soft tissues concentrated more {sup 137} Cs than shell. Remaining viscera showed the highest BFs. In another series of experiments, the loss of {sup 60} Co or {sup 137} Cs, previously accumulated by A. brasiliana, was followed in aquaria with or without sediment and the respective biological half-lives were calculated. Soft tissues retained {sup 60} Co longer (biological half-life = 117 days) than shells, whereas for {sup 137} Cs the opposite was observed and shells showed a biological half life of 38.5 days. The low values of {sup 60} Co and {sup 137} Cs BF{sub S} do not allow to classify A. brasiliana as good biological indicator for pollution by there radionuclides. However since A brasiliana is consumed by the local population and is commercialized to other areas, it was recommended that its contamination by {sup 60} Co or {sup 137} Cs should be monitored. (author).

Dosimetric evaluation of Radiotherapy units wit 60Co

International Nuclear Information System (INIS)

Leon, B. Salinas de; Tovar M, V.; Becerril V, A.

2000-01-01

The SSDL network of the IAEA performs, every year, quality audit tests for radiotherapy services ( 60 Co units and linear accelerators), and for national SSDL as well. Because of the SSDL-Mexico results in these tests and due to our enthusiasm and confidence in our work, a parallel test has been done , which is described in this talk as well as the results. Nowadays, a second parallel test goes up, which could confirm our optimism and open the possibility to our country to start a national dosimetric audit of 60 Co radiotherapy units. (Author)

Studies on the effectiveness of teleradiotherapy in laryngeal cancer

Energy Technology Data Exchange (ETDEWEB)

Skolyszewski, J [Instytut Onkologii, Krakow (Poland)

1973-01-01

Four hundred and eighty six previously untreated patients with cancer of the larynx were radically irradiated at the Institute of Oncology in Krakow in the years 1951--1966. Five-year cure rate without cancer symptoms after irradiation as the only treatment was 43% or 209 of 486 cases, and after surgery for recurrent cancer there were in addition, 55 survivors (11%). Dosage schemes of /sup 60/Co therapy for laryngeal tumor have been devised giving a dose of 6,000 rads per 24 fractions in 5 weeks. When irradiating the larynx together with cervical lymph nodes the dose of 6,000 rads was given during 6 to 7 weeks plus further irradiation at a lower dose if necessary. Two techniques of /sup 60/Co irradiation of typical cases of laryngeal cancer are described.

An experimental study of the effect of Co-60 irradiation on the healing process of extraction wounds in white rats

Energy Technology Data Exchange (ETDEWEB)

You, Young Jun; Ahn, Hyung Kyu [Dept. of Dental Radiology, Graduate School, Seoul National University, Seoul (Korea, Republic of)

1982-11-15

Because of the development of rampant caries, osteomyelitis and osteoradionecrosis that occur after radiation therapy of oral cancers, extraction of teeth at or near the malignant lesion has been done in the past. Few, however, have studied the radiation effect on the healing of extraction wounds. The study is concerned with the effect of Co-60 irradiation on the healing process of extraction wounds in rats. Fifty six, male, Sprague-Dawley rats are used. The right first molar of the mandible is extracted from all animals. They are divided into three experimental groups of 14 each and a control group of 14. There experimental groups are irradiated respectively with 200 rad, 400 rad and 600 rad and a pair of rats in each group are killed on days 1, 3, 5, 7, 14, 21 and 28 after irradiation. Two animals from the control group are killed on the day when the experimental rats are killed. The irradiated hemimandibles are fixed in 10% neutral formalin, decalcified in 5% trichloroacetic acid, embedded in paraffin and sectioned. The sections are stained in hematoxylin and eosin, van Gison, Masson's trichrome or silver nitrate. Results show that in general radiation effects on healing extraction wounds are dose dependent; i.e., the higher is the dose, the greater is the histologic changes observed: 1. Irradiation tends to retard blood clot organization and epithelial regeneration. 2. An increase in the number of giant cells and osteoclasts is noted after irradiation. 3. Formation of regenerating connective tissues around and within the extraction site is compromised, and a clear reduction of primitive mesenchymal type connective cells is noted. 4. The healing process begins along the lateral aspect of the extraction socket in the control, while irregular histologic appearances of the trabecular pattern is present in the experimental rats.

Whole-body retention of 60Co incorporated into a seaweed in rats

International Nuclear Information System (INIS)

Inaba, Jiro; Nishimura, Yoshikazu; Ichikawa, Ryushi

1979-01-01

The objective of this study is to compare whole-body retention in the rat of radiocobalt incorporated into a marine green alga with that of 60 Co in inorganic form. Ulva pertusa was incubated in aerated seawater containing 60 Co under fluorescent lamp for 7 days. The radioactive seaweed was homogenated and was given to rats via a stomach tube. The control group of rats was given 60 CoCl 2 with homogenate of non-radioactive seaweed. Whole-body retention of the radionuclide was determined by in vivo counting of the living animal. The result revealed that rats absorbed and retained much more 60 Co incorporated into the seaweed than 60 CoCl 2 . This fact should be taken into account in the estimation of internal dose due to radiocobalt released into marine environment. (author)

Placental transfer of 60Co as a function of gestation age

International Nuclear Information System (INIS)

Zylicz, E.; Zablotna, R.; Szot, Z.

1976-01-01

The transfer of 60 Co from mother to foetus in relation to the time of gestation was examined 24 hrs after injecting 5 μCi of 60 CoCl 2 to the pregnant rat on 15th - 21st day of gestation. The radioactivity of foetuses, placentae as well as liver, kidney and femur of mother was determined. It was found that activity of 60 Co transferred to the foetus body increased with the time of gestation. (author)

Strain differences in the response of mouse testicular stem cells to fractionated radiation

International Nuclear Information System (INIS)

Meistrich, M.L.; Finch, M.; Lu, C.C.; de Ruiter-Bootsma, A.L.; de Rooij, D.G.; Davids, J.A.G.

1984-01-01

The survival of spermatogonial stem cells in CBA and C3H mice after single and split-dose (24-hr interval) irradiation with fission neutrons and gamma rays was compared. The first doses of the fractionated regimes were either 150 rad (neutrons) or 600 rad (gamma). For both strains the neutron survival curves were exponential. The D 0 value of stem cells in CBA decreased from 83 to 25 rad upon fractionation; that of C3H stem cells decreased only from 54 to 36 rad. The survival curves for gamma irradiation, which all showed shoulders, indicated that C3H stem cells had larger repair capacities than CBA stem cells. However, the most striking difference between the two strains in response to gamma radiation was in the slopes of the second-dose curves. Whereas C3H stem cells showed a small increase of the D 0 upon fractionation (from 196 to 218 rad), CBA stem cells showed a marked decrease (from 243 to 148 rad). The decreases in D 0 upon fractionation, observed in both strains with neutron irradiation and also with gamma irradiation in CBA, are most likely the result of recruitment or progression of radioresistant survivors to a more sensitive state of proliferation or cell cycle phase. It may be that the survivng stem cells in C3H mice are recruited less rapidly and synchronously into active cycle than in CBA mice. Thus, it appears that the strain differences may be quantitative, rather than qualitative

Effect of cyanide on the distribution of 60Co in mice

International Nuclear Information System (INIS)

Frankenberg, L.

1982-01-01

The effect of cyanide on the distribution of cobalt was studied by injecting mice i.p. with potassium cyanide 61.4 μmoles/kg, followed 1 min later by 60 CoCl 2 38.5 μmoles/kg i.v. Blood and tissue concentrations of 60 Co were then determined up to 48 h after injection and the results were compared with those obtained from control animals receiving 60 CoCl 2 only. In animals treated with cobalt plus cyanide, considerably higher concentrations of 60 Co were found in the spleen in comparison with controls during the whole observation period, whereas the 60 Co concentration in the pancreas was lower than that of controls during the first 4 h. In other tissues no significant differences between cyanide-treated animals and controls were noticed. Determination of complex-bound cyanide demonstrated that the increased uptake of cobalt in the spleen observed in cyanide-treated animals was due to cobalt-cyanide complex(es). Cyanide did not affect the plasma protein binding of cobalt. (orig.)

Determination of {sup 60}Co sorption in natural clinoptilolite; Determinacion de la sorcion de {sup 60}Co en clinoptilolita natural

Energy Technology Data Exchange (ETDEWEB)

Hernandez B, E.; Granados C, F. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

1997-07-01

It was studied the clinoptilolite behavior coming from a deposit in Taxco, Guerrero in hydration and stabilization conditions with sodium for determining its sorption properties. The ion exchange process was carried out through gamma spectrometry using a CoCl{sub 2} solution marked with {sup 60} Co at p H 6.5 in different contact times. It was observed a maximum sorption of 0.408 m eq Co{sup +2}/g mineral, from 0.314 m eq Co{sup +2}/g mineral correspond at ion exchange. (Author)

Composition and immunoreactivity of the A60 complex and other cell fractions from Mycobacterium bovis BCG.

Science.gov (United States)

Cocito, C; Vanlinden, F

1995-02-01

Surface static cultures of Mycobacterium bovis BCG contained cells embedded in an extracellular matrix, whose mechanical removal yielded free cells that were pressure disrupted and fractionated into cytoplasm and walls. Cell envelopes were either mechanically disrupted or extracted with detergents. Intracellular and extracellular fractions were analysed for proteins, polysaccharides, and antigen 6O (A60), a major complex immunodominant in tuberculosis. A60 was present in extracellular matrix, cytoplasm and walls: it represented a substantial portion of the proteins and polysaccharides of these fractions. While the protein/polysaccharide ratio varied according to the origin of A60 preparations, the electrophoretic patterns of A60 proteins (which accounted for the immunogenicity of the complex) remained unchanged. Western blots pointed to the proteins present within the 29-45 kDa range as the A60 components endowed with the highest immunogenicity level. Since the most heavily stained protein bands in SDS-PAGE patterns were located outside the region best recognized by antisera, a striking discordance was found between concentration and immunogenicity patterns of A60 proteins. The electrophoretic patterns of A60- and non-A60-proteins from cytoplasm were also different. A60 complexes in dot blots and some electrophoresed A60 proteins reacted with monoclonal antibodies directed against lipoarabinomannan (LAM), a highly immunogenic polymer of cell envelope. This contaminating compound was removed from A60 with organic solvents and detergents. SDS-PAGE and Western blot patterns of proteins from delipidated A60 were similar to those of native A60 proteins.

Disparate requirements for the Walker A and B ATPase motifs ofhuman RAD51D in homologous recombination

Energy Technology Data Exchange (ETDEWEB)

Wiese, Claudia; Hinz, John M.; Tebbs, Robert S.; Nham, Peter B.; Urbin, Salustra S.; Collins, David W.; Thompson, Larry H.; Schild, David

2006-04-21

In vertebrates, homologous recombinational repair (HRR) requires RAD51 and five RAD51 paralogs (XRCC2, XRCC3, RAD51B, RAD51C, and RAD51D) that all contain conserved Walker A and B ATPase motifs. In human RAD51D we examined the requirement for these motifs in interactions with XRCC2 and RAD51C, and for survival of cells in response to DNA interstrand crosslinks. Ectopic expression of wild type human RAD51D or mutants having a non-functional A or B motif was used to test for complementation of a rad51d knockout hamster CHO cell line. Although A-motif mutants complement very efficiently, B-motif mutants do not. Consistent with these results, experiments using the yeast two- and three-hybrid systems show that the interactions between RAD51D and its XRCC2 and RAD51C partners also require a functional RAD51D B motif, but not motif A. Similarly, hamster Xrcc2 is unable to bind to the non-complementing human RAD51D B-motif mutants in co-immunoprecipitation assays. We conclude that a functional Walker B motif, but not A motif, is necessary for RAD51D's interactions with other paralogs and for efficient HRR. We present a model in which ATPase sites are formed in a bipartite manner between RAD51D and other RAD51 paralogs.

60Co Transfer Factor From Lutosol Soil To Leafy Vegetable (Ipomea reptans poir)

International Nuclear Information System (INIS)

Leli-Nirwani; Jumaher; Wahyudi

2003-01-01

It has been conducted 60 Co transfer study from Lutosol soil to leafy vegetable plant by using pot treatment system. The aim of the research is to obtain data of the transfer factor of 60 Co from lutosol soil to leafy vegetable plant. Pot experiment was carried out by using the complete random design to evaluate two treatment, namely soil with 60 Co and without 60 Co (as a control). 60 Co concentration was with 6.1371 kBq/pot. Tested plant and control plant amount to 12 pots. Each pot contains 1 kg of soil. After harvesting, the weight of dry plant was determined and was conducted with Spectrometer Gamma to 60 Co concentration in dry plant and dry soil. Transfer factor was found to between 0.02 and 0.68 and the average is 0.2068. (author)

Human RAD18 interacts with ubiquitylated chromatin components and facilitates RAD9 recruitment to DNA double strand breaks.

Directory of Open Access Journals (Sweden)

Akiko Inagaki

Full Text Available RAD18 is an ubiquitin ligase involved in replicative damage bypass and DNA double-strand break (DSB repair processes. We found that RPA is required for the dynamic pattern of RAD18 localization during the cell cycle, and for accumulation of RAD18 at sites of γ-irradiation-induced DNA damage. In addition, RAD18 colocalizes with chromatin-associated conjugated ubiquitin and ubiquitylated H2A throughout the cell cycle and following irradiation. This localization pattern depends on the presence of an intact, ubiquitin-binding Zinc finger domain. Using a biochemical approach, we show that RAD18 directly binds to ubiquitylated H2A and several other unknown ubiquitylated chromatin components. This interaction also depends on the RAD18 Zinc finger, and increases upon the induction of DSBs by γ-irradiation. Intriguingly, RAD18 does not always colocalize with regions that show enhanced H2A ubiquitylation. In human female primary fibroblasts, where one of the two X chromosomes is inactivated to equalize X-chromosomal gene expression between male (XY and female (XX cells, this inactive X is enriched for ubiquitylated H2A, but only rarely accumulates RAD18. This indicates that the binding of RAD18 to ubiquitylated H2A is context-dependent. Regarding the functional relevance of RAD18 localization at DSBs, we found that RAD18 is required for recruitment of RAD9, one of the components of the 9-1-1 checkpoint complex, to these sites. Recruitment of RAD9 requires the functions of the RING and Zinc finger domains of RAD18. Together, our data indicate that association of RAD18 with DSBs through ubiquitylated H2A and other ubiquitylated chromatin components allows recruitment of RAD9, which may function directly in DSB repair, independent of downstream activation of the checkpoint kinases CHK1 and CHK2.

Cellular Ubc2/Rad6 E2 ubiquitin-conjugating enzyme facilitates tombusvirus replication in yeast and plants

International Nuclear Information System (INIS)

Imura, Yoshiyuki; Molho, Melissa; Chuang, Chingkai; Nagy, Peter D.

2015-01-01

Mono- and multi-ubiquitination alters the functions and subcellular localization of many cellular and viral proteins. Viruses can co-opt or actively manipulate the ubiquitin network to support viral processes or suppress innate immunity. Using yeast (Saccharomyces cerevisiae) model host, we show that the yeast Rad6p (radiation sensitive 6) E2 ubiquitin-conjugating enzyme and its plant ortholog, AtUbc2, interact with two tombusviral replication proteins and these E2 ubiquitin-conjugating enzymes could be co-purified with the tombusvirus replicase. We demonstrate that TBSV RNA replication and the mono- and bi-ubiquitination level of p33 is decreased in rad6Δ yeast. However, plasmid-based expression of AtUbc2p could complement both defects in rad6Δ yeast. Knockdown of UBC2 expression in plants also decreases tombusvirus accumulation and reduces symptom severity, suggesting that Ubc2p is critical for virus replication in plants. We provide evidence that Rad6p is involved in promoting the subversion of Vps23p and Vps4p ESCRT proteins for viral replicase complex assembly. - Highlights: • Tombusvirus p33 replication protein interacts with cellular RAD6/Ubc2 E2 enzymes. • Deletion of RAD6 reduces tombusvirus replication in yeast. • Silencing of UBC2 in plants inhibits tombusvirus replication. • Mono- and bi-ubiquitination of p33 replication protein in yeast and in vitro. • Rad6p promotes the recruitment of cellular ESCRT proteins into the tombusvirus replicase

Cellular Ubc2/Rad6 E2 ubiquitin-conjugating enzyme facilitates tombusvirus replication in yeast and plants

Energy Technology Data Exchange (ETDEWEB)

Imura, Yoshiyuki, E-mail: imura@brs.nihon-u.ac.jp; Molho, Melissa; Chuang, Chingkai; Nagy, Peter D., E-mail: pdnagy2@uky.edu

2015-10-15

Mono- and multi-ubiquitination alters the functions and subcellular localization of many cellular and viral proteins. Viruses can co-opt or actively manipulate the ubiquitin network to support viral processes or suppress innate immunity. Using yeast (Saccharomyces cerevisiae) model host, we show that the yeast Rad6p (radiation sensitive 6) E2 ubiquitin-conjugating enzyme and its plant ortholog, AtUbc2, interact with two tombusviral replication proteins and these E2 ubiquitin-conjugating enzymes could be co-purified with the tombusvirus replicase. We demonstrate that TBSV RNA replication and the mono- and bi-ubiquitination level of p33 is decreased in rad6Δ yeast. However, plasmid-based expression of AtUbc2p could complement both defects in rad6Δ yeast. Knockdown of UBC2 expression in plants also decreases tombusvirus accumulation and reduces symptom severity, suggesting that Ubc2p is critical for virus replication in plants. We provide evidence that Rad6p is involved in promoting the subversion of Vps23p and Vps4p ESCRT proteins for viral replicase complex assembly. - Highlights: • Tombusvirus p33 replication protein interacts with cellular RAD6/Ubc2 E2 enzymes. • Deletion of RAD6 reduces tombusvirus replication in yeast. • Silencing of UBC2 in plants inhibits tombusvirus replication. • Mono- and bi-ubiquitination of p33 replication protein in yeast and in vitro. • Rad6p promotes the recruitment of cellular ESCRT proteins into the tombusvirus replicase.

Determination of 60Co sorption in natural clinoptilolite

International Nuclear Information System (INIS)

Hernandez B, E.; Granados C, F.

1997-01-01

It was studied the clinoptilolite behavior coming from a deposit in Taxco, Guerrero in hydration and stabilization conditions with sodium for determining its sorption properties. The ion exchange process was carried out through gamma spectrometry using a CoCl 2 solution marked with 60 Co at p H 6.5 in different contact times. It was observed a maximum sorption of 0.408 m eq Co +2 /g mineral, from 0.314 m eq Co +2 /g mineral correspond at ion exchange. (Author)

RadConEd: A Graphical Data Editor for the Radiological Consequences Model, RadCon

International Nuclear Information System (INIS)

Crawford, J.; Domel, R.U.

2000-05-01

This document describes the application, RadConEd, which has been designed and implemented to enable users of the RadCon system to update these parameter files. The RadCon system is written in the Java programming language, and as such provides portability across computer platforms. The software described in this report was developed in line with the portability requirements of RadCon, thus providing a uniform user interface across computer platforms and bypassing the need of using system editors. In addition a number of data integrity measures were implemented

Study on the resistance of haloferax radiotolerans, an extreme Halophilic archaebacterium from Uromia lake against ultraviolet (UV) light and 60Co gamma-rays

International Nuclear Information System (INIS)

Asgarni, E.; Shirzad, M.; Soudi, M. R.; Shahmohammadi, H. R.; Falsafi, T.

2006-01-01

In this work, the capacity of an extreme halophilic archaebacterium, isolated from Uromia lake, Haloferax radiotolerans to withstand the lethal effects of ultraviolet light (UV),and 60 Co r-rays has been studied. The resistibility of this organism against the DNA-damaging agents was evaluated by calculating of the survival fractions at different dose rates of W and 60 Co r-rays radiations and compared with those of Escherichia coli B/r (a radioresistant strain of E. coli). D 37 values for Haloferax radiotolerans and E. coli B/r were 23 1, and 9 J/m 2 , respectively, by exposure to the UV light. They were 645, and 99 Gy, respectively, by exposure to 60 Co r-rays. Against these agents, Haloferax radiotolerans shows much more resistance compare to that of E. coli B/r. This is categorized as the first report of resistibility in the member of Archaea

Hydrogen/deuterium fractionation factors of the aqueous ligand of cobalt in Co(H2O)62+ and Co(II)-substituted carbonic anhydrase

International Nuclear Information System (INIS)

Kassebaum, J.W.

1988-01-01

The author has measured the hydrogen/deuterium fractionation factor for the rapidly exchanging aqueous ligands of cobalt in Co(H 2 O) 6 2+ and in three Co(II)-substituted isozymes of carbonic anhydrase. The fractionation factor was determined from NMR relaxation rates at 300 MHz of the protons of water in mixed solutions of H 2 O and D 2 O containing these complexes. In each case, the paramagnetic contribution to 1/T 2 was greater than to 1/T 1 , consistent with a chemical shift mechanism affecting 1/T 2 . The fractionation factors obtained from T 2 were 0.73 ± 0.02 for Co(H 2 O) 6 2+ , 0.72 ± 0.02 for Co(II)-substituted carbonic anhydrase I, 0.77 ± 0.01 for Co(II)-substituted carbonic anhydrase II, and 1.00 ± 0.07 for Co(Il)-substituted carbonic anhydrase III. He concluded that fractionation factors in these cases determined from T 1 and T 2 measured isotope preferences for different populations of ligand sites. Since T 2 has a large contribution from a chemical shift mechanism, the fractionation factor determined from T 2 has a large contribution of the fractionation of inner shell ligands. The fractionation factor of Co(H 2 O) 6 2+ was used to interpret the solvent hydrogen isotope effects on the formation of complexes of cobalt with the bidentate ligands glycine, N,N-dimethylglycine, and acetylacetone. The contribution of the fractionation factor of the inner water shell in Co(H 2 O) 6 2+ did not account completely for the measured isotope effect, and that the hydrogen/deuterium fractionation of outer shell water makes a large contribution to the isotope effect on the formation of these complexes

Effect of cobalt 60 gamma-ray irradiation on the hatching process of chicken eggs

International Nuclear Information System (INIS)

Ohkuma, Yoshikazu

1981-01-01

An experiment on fertilized chicken eggs was carried out to determine the effects of 60 Co irradiation on the embryos, their fatality, and growth impairment or deformity, in particular. The experimental groups, consisting of 10 eggs each, recieved a 60 Co irradiation of 50 to 2,000 rads on any one day between day 0 and day 20 of incubation. The larger the irradiation dose, the greater was the number of dead embryos. The fatality was higher in the groups receiving irradiation in the earlier stage (1st week). The resultant death was a chronic one. The irradiation also caused body weight decrease and growth impairment. A decrease in the brain and liver weights was noted, suggesting insufficiency in these organs. Deformity occurred in 4%, most of which involved impairments of skeletal growth, of the bones of the extremities and the bill, in particular. Administration of the SH amino acid, cysteine tended to alleviate the adverse effects of the 60 Co irradiation. These results for fertilized chicken eggs suggest the possibility of abortion and the occurrence of deformities in human fetuses if they should be subjected to 60 Co irradiation. (author)

The application of PLC in 60Co container inspection system

International Nuclear Information System (INIS)

Huang Yibin; Xiang Xincheng

2001-01-01

The author discusses the interlock technique of 60 Co container inspection system, and introduces the hardware structure and program of interlock control system using PLC. Due to adopting PLC distributed control, the system works stably and reliably. The successful application of PLC in 60 Co container inspection system has some use for reference in nuclear technology field

Radiographic Co-60 in component of heavy equipment casting

International Nuclear Information System (INIS)

Djoli Soembogo, Harun Al Rasyid R dan Namad Sianta

2016-01-01

The application of radiography using isotope Co-60 source has been used on component of heavy equipment such as component of heavy equipment casting. Components of heavy equipment casting made through metal casting of carbon steel. This study tried applying digital radiography are using isotope Co-60 sources and using scanning positive film media of Epson V700 for digitization results of conventional radiographic films. This radiography is using film AGFA D7 and Fuji 100 to obtain a contrast medium, medium sensitivity and image quality is good. The purpose radiographic Co-60 at a component of heavy equipment casting is detecting indications of the shape and type casting defects of component of heavy equipment casting thus fit for use. Radiographic test of Co-60 has been carried out on component of heavy equipment casting with single wall single image method and the results of radiographic films digitization using scanning positive film media of Epson V700 with observation parameters casting defects. Time exposure of Co-60 radiation was 10 and 15 minutes hours for metal castings of carbon steel for thickness 20.00-50.00 mm by using activity 30.05 Ci and the perpendicular distance to the source of the film is 820 mm. Scanner positive film results in the form of digital radiography which allow for the transfer of digital data or digital computerized data storage. Radiographic test results on component of heavy equipment casting with single wall single image method produce the parameter casting defect of component of heavy equipment casting in position of critical area is found shrinkage that should be repaired and in position of safety area is not found defect indication so casting defect of component of heavy equipment casting are not acceptable according to standards referenced. (author)

Determination of contamination-free build-up for 60Co

International Nuclear Information System (INIS)

Higgins, P.D.; Sibata, CH.; Paliwal, B.R.

1985-01-01

Experimental verification of the difference between absorbed dose in tissue and the collision fraction of kerma requires precise knowledge of the absorbed dose curve, particularly in the build-up and build-down regions. A simple method from direct measurement of contamination-free build-up for 60 Co, which should also be applicable for most of the photon energies commonly employed for treatment, is presented. It is shown that the contribution from air-scattered electrons to the surface dose may be removed by extrapolating measurements of build-up to zero field size. The remaining contribution to contamination from the collimators and other source-related hardware may be minimised by measuring these build-up curves sufficiently far from the source. These results were tested by measuring the build-up using a magnet to sweep scattered electrons from the primary photon beam and by measuring the surface dose in the limit of an evacuated beam path. The relative dose at zero depth in polystyrene was found to be approximately 8.9+-0.3% of the dose at the depth of maximum build-up. (author)

Different gamma ray (60 Co) dose effects on Sorghum genotype germination

International Nuclear Information System (INIS)

Tabosa, Jose Nildo; Gomes, Roberto Vicente; Reis, Odemar Vicente dos; Colaco, Waldeciro

2004-01-01

In agriculture, applying irradiation is a very valuable way of obtaining vegetable products for human and animal consumption. Cobalt-60, one of the main sources of gamma-rays, is considered an important tool in plant breeding programs, which have the objective of promoting genetic variability of cultivars with resistance to adverse environments. In this research, the effects of different 60 Co doses on germination vigor and seed germination velocity of forage sorghum genotypes were evaluated. The study was carried out at the IPA (Empresa Pernambucana de Pesquisa Agropecuaria) in Recife, Pernambuco, Brazil. The work was installed in germination boxes, following laboratory recommendations. Thus, a experiment involving three sorghum genotypes (IPA 467-4-2, IPA 02-03-01, and Sudan 4202), five 60 Co doses (Zero, 150, 300, 350, and 400 Gy), was set up. The sees were irradiated before the beginning of the experiment being exposed to gamma rays from a 60 Co-source (cobalt irradiator) at DEN (Nuclear Engineering Department) of the UFPE (Pernambuco Federal University), Brazil. The work also had the objective of evaluating the sorghum genotypes x 60 Co dose interaction. The main results obtained showed that the sorghum genotype IPA 02-03-01 presented the greatest values of germination and vigor percentages, and seed germination velocity, when compared to the others evaluated, on 350 and 400 Gy of 60 Co doses. (author)

Sterilization of boll weevil pupae with fractionated doses of gamma irradiation

International Nuclear Information System (INIS)

Haynes, J.W.; Mitlin, N.; Davich, T.B.; Dawson, J.R.; McGovern, W.L.; McKibben, G.H.

1977-01-01

Fractionated doses of 6,250-8,000 rads of gamma irradiation administered to pupae of the boll weevil, Anthonomus grandis Boh., sexually sterilized both sexes. Mortality of males thus treated with 6,250 and 8,000 rads via fractionation was 14% and 27% respectively, by 5 days posttreatment compared with 46% mortality when an equivalent acute dose was administered to newly emerged adults. Pheromone production of males irradiated at 6,250 rads was one-third that of the control for the first 4 days, but equal that of the control during 5-11 days posttreatment. This procedure lends itself to the large-scale sterilization of weevils needed in an eradication program. This technique is applicable to other insects that are highly susceptible to acute doses

Disparate requirements for the Walker A and B ATPase motifs of human RAD51D in homologous recombination.

Science.gov (United States)

Wiese, Claudia; Hinz, John M; Tebbs, Robert S; Nham, Peter B; Urbin, Salustra S; Collins, David W; Thompson, Larry H; Schild, David

2006-01-01

In vertebrates, homologous recombinational repair (HRR) requires RAD51 and five RAD51 paralogs (XRCC2, XRCC3, RAD51B, RAD51C and RAD51D) that all contain conserved Walker A and B ATPase motifs. In human RAD51D we examined the requirement for these motifs in interactions with XRCC2 and RAD51C, and for survival of cells in response to DNA interstrand crosslinks (ICLs). Ectopic expression of wild-type human RAD51D or mutants having a non-functional A or B motif was used to test for complementation of a rad51d knockout hamster CHO cell line. Although A-motif mutants complement very efficiently, B-motif mutants do not. Consistent with these results, experiments using the yeast two- and three-hybrid systems show that the interactions between RAD51D and its XRCC2 and RAD51C partners also require a functional RAD51D B motif, but not motif A. Similarly, hamster Xrcc2 is unable to bind to the non-complementing human RAD51D B-motif mutants in co-immunoprecipitation assays. We conclude that a functional Walker B motif, but not A motif, is necessary for RAD51D's interactions with other paralogs and for efficient HRR. We present a model in which ATPase sites are formed in a bipartite manner between RAD51D and other RAD51 paralogs.

Simultaneously reducing CO2 and particulate exposures via fractional recirculation of vehicle cabin air.

Science.gov (United States)

Jung, Heejung S; Grady, Michael L; Victoroff, Tristan; Miller, Arthur L

2017-07-01

Prior studies demonstrate that air recirculation can reduce exposure to nanoparticles in vehicle cabins. However when people occupy confined spaces, air recirculation can lead to carbon dioxide (CO 2 ) accumulation which can potentially lead to deleterious effects on cognitive function. This study proposes a fractional air recirculation system for reducing nanoparticle concentration while simultaneously suppressing CO 2 levels in the cabin. Several recirculation scenarios were tested using a custom-programmed HVAC (heat, ventilation, air conditioning) unit that varied the recirculation door angle in the test vehicle. Operating the recirculation system with a standard cabin filter reduced particle concentrations to 1000 particles/cm 3 , although CO 2 levels rose to 3000 ppm. When as little as 25% fresh air was introduced (75% recirculation), CO 2 levels dropped to 1000 ppm, while particle concentrations remained below 5000 particles/cm 3 . We found that nanoparticles were removed selectively during recirculation and demonstrated the trade-off between cabin CO 2 concentration and cabin particle concentration using fractional air recirculation. Data showed significant increases in CO 2 levels during 100% recirculation. For various fan speeds, recirculation fractions of 50-75% maintained lower CO 2 levels in the cabin, while still reducing particulate levels. We recommend fractional recirculation as a simple method to reduce occupants' exposures to particulate matter and CO 2 in vehicles. A design with several fractional recirculation settings could allow air exchange adequate for reducing both particulate and CO 2 exposures. Developing this technology could lead to reductions in airborne nanoparticle exposure, while also mitigating safety risks from CO 2 accumulation.

Development of irradiator 60Co sources

International Nuclear Information System (INIS)

Mosca, Rodrigo C.; Moura, Eduardo S.; Zeituni, Carlos A.; Mathor, Monica B.

2011-01-01

According to a recent report by the International Agency for Research on Cancer (IARC) / WHO (2008-2010), the global impact of cancer more than doubled in 30 years. In this report, it was estimated that occurred about 12 million new cancer cases and 7 million deaths. In Brazil in 2010, with estimates for the year 2011, point to the occurrence of 489,270 new cases of cancer. Among the possibilities for cancer treatment, radiotherapy is one of the most important therapeutic and resources used to combat it. However, inherent complications of treatment can occur such as tiredness, loss of appetite, radiodermatitis and in more extreme cases late radionecrosis. In order to reproduce a point of radionecrosis in the vicinity of radiodermatitis to mimic these effects in animals, producing a model for assessment of tissue repair, we propose the setting up of an irradiator source of collimated 60 Co. The development of was based on 11 sources of 60 Co with 1 mm thickness that were inserted by inference in stainless steel 'gate-source' screw (patent pending) and later adjusted in a cross-shaped arrangement reinforced so that the beam radiation is directed to a target point, saving for other regions around this target point. The main use of this irradiator with sources of 60 Co is just one cause radionecrosis point (target point) of approximately 5 mm 2 with a surrounding and adjacent area of radiodermatitis around about 8 to 10 mm 2 in laboratory animals for subsequent coating with epidermal-dermal matrix populated by a cell culture of human fibroblasts, keratinocytes and mesenchymal stem cells. With that said, its use will be valuable for evaluation of curative treatments against the bone and radionecrosis or palliative treatment rather than as it is currently assumed. (author)

Analysis list: RAD21 [Chip-atlas[Archive

Lifescience Database Archive (English)

Full Text Available ncedbc.jp/kyushu-u/hg19/target/RAD21.1.tsv http://dbarchive.biosciencedbc.jp/kyushu...-u/hg19/target/RAD21.5.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/target/RAD21.10.tsv http://dbarchive.bioscience...dbc.jp/kyushu-u/hg19/colo/RAD21.Blood.tsv,http://dbarchive.bioscience...dbc.jp/kyushu-u/hg19/colo/RAD21.Breast.tsv,http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/colo/RAD21.Dige...stive_tract.tsv,http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/colo/RAD21.Liver.tsv,http://dbarchive.bioscience

Characterization of the interaction between the cohesin subunits Rad21 and SA1/2.

Directory of Open Access Journals (Sweden)

Nenggang Zhang

Full Text Available The cohesin complex is responsible for the fidelity of chromosomal segregation during mitosis. It consists of four core subunits, namely Rad21/Mcd1/Scc1, Smc1, Smc3, and one of the yeast Scc3 orthologs SA1 or SA2. Sister chromatid cohesion is generated during DNA replication and maintained until the onset of anaphase. Among the many proposed models of the cohesin complex, the 'core' cohesin subunits Smc1, Smc3, and Rad21 are almost universally displayed as tripartite ring. However, other than its supportive role in the cohesin ring, little is known about the fourth core subunit SA1/SA2. To gain deeper insight into the function of SA1/SA2 in the cohesin complex, we have mapped the interactive regions of SA2 and Rad21 in vitro and ex vivo. Whereas SA2 interacts with Rad21 through a broad region (301-750 aa, Rad21 binds to SA proteins through two SA-binding motifs on Rad21, namely N-terminal (NT and middle part (MP SA-binding motif, located at 60-81 aa of the N-terminus and 383-392 aa of the MP of Rad21, respectively. The MP SA-binding motif is a 10 amino acid, α-helical motif. Deletion of these 10 amino acids or mutation of three conserved amino acids (L(385, F(389, and T(390 in this α-helical motif significantly hinders Rad21 from physically interacting with SA1/2. Besides the MP SA-binding motif, the NT SA-binding motif is also important for SA1/2 interaction. Although mutations on both SA-binding motifs disrupt Rad21-SA1/2 interaction, they had no apparent effect on the Smc1-Smc3-Rad21 interaction. However, the Rad21-Rad21 dimerization was reduced by the mutations, indicating potential involvement of the two SA-binding motifs in the formation of the two-ring handcuff for chromosomal cohesion. Furthermore, mutant Rad21 proteins failed to significantly rescue precocious chromosome separation caused by depletion of endogenous Rad21 in mitotic cells, further indicating the physiological significance of the two SA-binding motifs of Rad21.

Roles of Rad51 protein in homologous recombination in mammalian cells: relation with repair, replication and cell cycle

International Nuclear Information System (INIS)

Lambert, S.

2001-01-01

Homologous recombination (HR) is a fundamental process, allowing a faithful repair. In mammalian, MmRAD51, which is the homologue of Saccharomyces cerevisiae ScRAD51 key protein for HR, is an essential gene. This work is based on the characterisation of viable hyper and hypo-recombinant cell lines specifically affected in the Rad51 pathway. By expressing wild type and dominant negative forms of MmRad51, we demonstrated that Rad51 pathway participates to the repair by HR to induced DNA damages. However, inhibition of the Rad 51 pathway does not affect cell viability, spontaneously or after irradiation, whereas, radiation induced HR is inhibited. In the presence of DNA damages during late S and G2/M phase, inhibition of Rad51 pathway induced chromosomal aberrations, leading to a transient arrest in mitosis. This arrest is associated with an increased of cell death. However, a fraction of cells can escape from this transient arrest by forming tetraploid cells, associated with an absence of chromalid separation. Thus, in response to impaired Rad51 pathway, mitotic checkpoints seems to play an essential role. In line with this, we showed that the essential function of Rad51 is p53-dependent, which is in agreement with the role of p53 in tetraploidy inhibition. Our results suggest that the Rad51 protein could participate to the control of mitotic checkpoints and thus to the maintenance of genetic stability. This function could involve other Rad51 partners such as the tumour suppressors BRCA1, BRCA2 and p53. (author) [fr

Mutant in tobacco anther culture induced by 60Co γ-rays

International Nuclear Information System (INIS)

Tong Daoru; Jia Xinghua

1991-01-01

The tobacco anthers at uninucleate eccentric stage were irradiated by 60 Co γ-rays for the purpose of inducing desirable mutants. The results showed that the induction frequency of plantlets increased following 1kR of 60 Co γ-rays treatment. However, the time of plantlet induction was delayed and the percentage of responding anthers as well as the number of plantlets induced per anther significantly decreased after 3kR of 60 Co γ-ray radiation which was considered as a semilethal exposure. The plantlet numbers induced per anther were extremely low following 6kR of 60 Co γ-ray radiation. A white flower mutant appeared in the induced progenies. The tobacco leaf quality of this mutant were significantly improved as compared with its parental line. The mutant line has been tested and proved to have commercial value though the resistance to the black shank of tobacco slightly decreased as compared with the parental line

The RadAssessor manual

Energy Technology Data Exchange (ETDEWEB)

Seitz, Sharon L.

2007-02-01

THIS manual will describe the functions and capabilities that are available from the RadAssessor database and will demonstrate how to retrieve and view its information. You’ll learn how to start the database application, how to log in, how to use the common commands, and how to use the online help if you have a question or need extra guidance. RadAssessor can be viewed from any standard web browser. Therefore, you will not need to install any special software before using RadAssessor.

Roles of C-Terminal Region of Yeast and Human Rad52 in Rad51-Nucleoprotein Filament Formation and ssDNA Annealing.

Directory of Open Access Journals (Sweden)

Nilesh V Khade

Full Text Available Yeast Rad52 (yRad52 has two important functions at homologous DNA recombination (HR; annealing complementary single-strand DNA (ssDNA molecules and recruiting Rad51 recombinase onto ssDNA (recombination mediator activity. Its human homolog (hRAD52 has a lesser role in HR, and apparently lacks mediator activity. Here we show that yRad52 can load human Rad51 (hRAD51 onto ssDNA complexed with yeast RPA in vitro. This is biochemically equivalent to mediator activity because it depends on the C-terminal Rad51-binding region of yRad52 and on functional Rad52-RPA interaction. It has been reported that the N-terminal two thirds of both yRad52 and hRAD52 is essential for binding to and annealing ssDNA. Although a second DNA binding region has been found in the C-terminal region of yRad52, its role in ssDNA annealing is not clear. In this paper, we also show that the C-terminal region of yRad52, but not of hRAD52, is involved in ssDNA annealing. This suggests that the second DNA binding site is required for the efficient ssDNA annealing by yRad52. We propose an updated model of Rad52-mediated ssDNA annealing.

A New In-core Production Method of Co-60 in CANDU Reactors

Energy Technology Data Exchange (ETDEWEB)

Lyu, Jinqi; Kim, Woosong; Kim, Yonghee [KAIST, Daejeon (Korea, Republic of); Park, Younwon [BEES Inc, Daejeon (Korea, Republic of)

2016-05-15

This study introduces an innovative method for Co-60 production in the CANDU6 core. In this new scheme, the central fuel element is replaced by a Co-59 target and Co-60 is obtained after the fuel bundle is discharged. It has been shown that the new method can produce significantly higher amount of Co-60 than the conventional Co production method in CANDU6 reactors without compromising the fuel burnup by removing some (<50%) of the adjuster rods in the whole core. The coolant void reactivity is noticeably reduced when a Co-59 target is loaded into the central pin of the fuel bundle. Meanwhile, the peak power in a fuel bundle is just a little higher due to the central Co-59 target than in conventional CANDU6 fuel design. The basic technology for Co-60 producing was developed by MDS Nordion and Atomic Energy of Canada Limited (AECL) in 1946 and the same technology was adapted and applied in CANDU6 power reactors. The standard CANDU6 reactor has 21 adjuster rods which are fully inserted into the core during normal operation. The stainless steel adjuster rods are replaced with neutronically-equivalent Co-59 adjusters to produce Co-60. Nowadays, the roles of the adjuster rods are rather vague since nuclear reactors cannot be quickly restarted after a sudden reactor trip due to more stringent regulations. In some Canadian CANDU6 reactors, some or all the adjuster rods are removed from the core to maximize the uranium utilization.

Soil-plant transfer factors of Co-60 for alfalfa lettuce and spinach

International Nuclear Information System (INIS)

Dumitru, Radu Octavian

1997-01-01

The transfer of Co-60 from soil into plants is a less studied problem. Soil-plant transfer factors for Co-60 known from literature vary by about four orders of magnitude for each kind of plants. We have calculated the average values and have determined the field of variability of the known transfer factors. These indicated us that alfalfa, lettuce and spinach have in this order the greatest absorption capacity of Co-60 from soil. We have determined the physical, chemical and mineralogical properties of the utilized soil. This is a brown reddish forest type soil. The plants have been cultivated in pots by plantlet method of Neubauer and Schneider. The results of our measurements of soil-to-plant transfer factors of 60-Co are the followings: 0.0612 ± 0.0047 for alfalfa, 0.0960 ± 0.0072 for lettuce and 0.1446 ± 0.0107 for spinach. These values prove the strong dependence of the type of soil and plant of the soil-plant transfer factors for Co-60. (author)

Safety and feasibility of STAT RAD: Improvement of a novel rapid tomotherapy-based radiation therapy workflow by failure mode and effects analysis.

Science.gov (United States)

Jones, Ryan T; Handsfield, Lydia; Read, Paul W; Wilson, David D; Van Ausdal, Ray; Schlesinger, David J; Siebers, Jeffrey V; Chen, Quan

2015-01-01

The clinical challenge of radiation therapy (RT) for painful bone metastases requires clinicians to consider both treatment efficacy and patient prognosis when selecting a radiation therapy regimen. The traditional RT workflow requires several weeks for common palliative RT schedules of 30 Gy in 10 fractions or 20 Gy in 5 fractions. At our institution, we have created a new RT workflow termed "STAT RAD" that allows clinicians to perform computed tomographic (CT) simulation, planning, and highly conformal single fraction treatment delivery within 2 hours. In this study, we evaluate the safety and feasibility of the STAT RAD workflow. A failure mode and effects analysis (FMEA) was performed on the STAT RAD workflow, including development of a process map, identification of potential failure modes, description of the cause and effect, temporal occurrence, and team member involvement in each failure mode, and examination of existing safety controls. A risk probability number (RPN) was calculated for each failure mode. As necessary, workflow adjustments were then made to safeguard failure modes of significant RPN values. After workflow alterations, RPN numbers were again recomputed. A total of 72 potential failure modes were identified in the pre-FMEA STAT RAD workflow, of which 22 met the RPN threshold for clinical significance. Workflow adjustments included the addition of a team member checklist, changing simulation from megavoltage CT to kilovoltage CT, alteration of patient-specific quality assurance testing, and allocating increased time for critical workflow steps. After these modifications, only 1 failure mode maintained RPN significance; patient motion after alignment or during treatment. Performing the FMEA for the STAT RAD workflow before clinical implementation has significantly strengthened the safety and feasibility of STAT RAD. The FMEA proved a valuable evaluation tool, identifying potential problem areas so that we could create a safer workflow

Efficacy and Safety of Fractional CO2 Laser Resurfacing in Non-hypertrophic Traumatic and Burn Scars

Science.gov (United States)

Majid, Imran; Imran, Saher

2015-01-01

Background: Fractional photothermolysis is one of the most effective treatment options used to resurface scars of different aetiologies. Aim: To assess the efficacy and safety of fractional CO2 laser resurfacing treatment in the management of non-hypertrophic traumatic and burn scars. Materials and Methods: Twenty-five patients affected by non-hypertrophic traumatic and burn scars were treated with four sessions of fractional CO2 laser resurfacing treatment at 6-weekly intervals. Patients were photographed at each visit and finally, 3 months after the end of treatment schedule. Response to treatment was assessed clinically as well as by comparing the initial photograph of the patient with the one taken at the last follow-up visit 3-months after the final treatment session. Changes in skin texture, surface irregularity and pigmentation were assessed on a quartile grading scale and scored individually from 0 to 4. A mean of the three individual scores was calculated and the response was labelled as ‘excellent’ if the mean score achieved was >2. A score of 1-2 was labeled as good response while a score below 1 was labeled as ‘poor’ response. The subjective satisfaction of each patient with the treatment offered was also assessed at the last follow-up visit. Results: The commonest site of scarring treated was the face followed by hands. Response to treatment was rated as excellent in 60% (15/25) patients while 24% (6/25) and 16% (4/25) patients were labeled as good and poor responders, respectively. Skin texture showed better response than other variables with average score of 2.44. Linear post-traumatic scars were seen to respond less than other morphological types. Majority of the patients (19 out of 25) were highly satisfied with the treatment offered. No long-term adverse effects were noted in any patient. Conclusions: Fractional photothermolysis with a fractional CO2 laser gives excellent results in patients with post-burn scars with minimal adverse

Efficacy and safety of fractional CO 2 laser resurfacing in non-hypertrophic traumatic and burn scars

Directory of Open Access Journals (Sweden)

Imran Majid

2015-01-01

Full Text Available Background: Fractional photothermolysis is one of the most effective treatment options used to resurface scars of different aetiologies. Aim: To assess the efficacy and safety of fractional CO 2 laser resurfacing treatment in the management of non-hypertrophic traumatic and burn scars. Materials and Methods: Twenty-five patients affected by non-hypertrophic traumatic and burn scars were treated with four sessions of fractional CO 2 laser resurfacing treatment at 6-weekly intervals. Patients were photographed at each visit and finally, 3 months after the end of treatment schedule. Response to treatment was assessed clinically as well as by comparing the initial photograph of the patient with the one taken at the last follow-up visit 3-months after the final treatment session. Changes in skin texture, surface irregularity and pigmentation were assessed on a quartile grading scale and scored individually from 0 to 4. A mean of the three individual scores was calculated and the response was labelled as ′excellent′ if the mean score achieved was >2. A score of 1-2 was labeled as good response while a score below 1 was labeled as ′poor′ response. The subjective satisfaction of each patient with the treatment offered was also assessed at the last follow-up visit. Results: The commonest site of scarring treated was the face followed by hands. Response to treatment was rated as excellent in 60% (15/25 patients while 24% (6/25 and 16% (4/25 patients were labeled as good and poor responders, respectively. Skin texture showed better response than other variables with average score of 2.44. Linear post-traumatic scars were seen to respond less than other morphological types. Majority of the patients (19 out of 25 were highly satisfied with the treatment offered. No long-term adverse effects were noted in any patient. Conclusions: Fractional photothermolysis with a fractional CO 2 laser gives excellent results in patients with post-burn scars with

C60-pentacene network formation by 2-D co-crystallization.

Science.gov (United States)

Jin, Wei; Dougherty, Daniel B; Cullen, William G; Robey, Steven; Reutt-Robey, Janice E

2009-09-01

We report experiments highlighting the mechanistic role of mobile pentacene precursors in the formation of a network C(60)-pentacene co-crystalline structure on Ag(111). This co-crystalline arrangement was first observed by low temperature scanning tunneling microscopy (STM) by Zhang et al. (Zhang, H. L.; Chen, W.; Huang, H.; Chen, L.; Wee, A. T. S. J. Am. Chem. Soc. 2008, 130, 2720-2721). We now show that this structure forms readily at room temperature from a two-dimensional (2-D) mixture. Pentacene, evaporated onto Ag(111) to coverages of 0.4-1.0 ML, produces a two-dimensional (2-D) gas. Subsequently deposited C(60) molecules combine with the pentacene 2-D gas to generate a network structure, consisting of chains of close-packed C(60) molecules, spaced by individual C(60) linkers and 1 nm x 2.5 nm pores containing individual pentacene molecules. Spontaneous formation of this stoichiometric (C(60))(4)-pentacene network from a range of excess pentacene surface coverage (0.4 to 1.0 ML) indicates a self-limiting assembly process. We refine the structure model for this phase and discuss the generality of this co-crystallization mechanism.

Influence Of Dilution Factor For Activity Measurement Of 60CO

International Nuclear Information System (INIS)

Hermawan-Candra; Nazaroh; Ermi-Juita

2003-01-01

Influence of dilution factor for activity measurement of 60 Co has been studied. The aim of this research is to determine influence between activity measurement result of 60 Co before and after diluted. Measurement were done by using ionization chamber detectors system and gamma spectrometry system with NaI(TI) detector. Discrepancy within three ionization chambers measurements were 0.2% - 2.1% and NaI(Tl) were 3.5% - 6%. (author)

Structural and magnetic properties of Co films on highly textured and randomly oriented C_6_0 layers

International Nuclear Information System (INIS)

Kim, Dong-Ok; Choi, Jun Woo; Lee, Dong Ryeol

2016-01-01

The structural and magnetic properties of Co/C_6_0/pentacene and Co/C_6_0 thin film structures were investigated. Atomic force microscopy and x-ray reflectivity analysis show that the presence or absence of a pentacene buffer layer leads to a highly textured or randomly oriented C_6_0 layer, respectively. A Co film deposited on a randomly oriented C_6_0 layer penetrates into the C_6_0 layer when it is deposited at a slow deposition rate. The Co penetration can be minimized, regardless of the Co deposition rate, by growth on a highly textured and nanostructured C_6_0/pentacene layer. Vibrating sample magnetometry measurements show that the saturation magnetization of Co/C_6_0/pentacene is significantly reduced compared to that of Co/C_6_0. On the other hand, the Co penetration does not seem to have an effect on the magnetic properties, suggesting that the structural properties of the Co and C_6_0 layer, rather than the Co penetration into the organic C_6_0 layer, are critical to the magnetic properties of the Co/C_6_0. - Highlights: • Structural and magnetic properties of metal(Co)-organic(C_6_0) interface is studied. • Highly textured C_6_0 layer was grown on a pentacene buffer layer (C_6_0/pentacene). • Co penetration into the C_6_0 is significantly suppressed in Co/C_6_0/pentacene. • The Co magnetization in Co/C_6_0/pentacene is reduced than that in Co/C_6_0.

Structural and magnetic properties of Co films on highly textured and randomly oriented C{sub 60} layers

Energy Technology Data Exchange (ETDEWEB)

Kim, Dong-Ok [Department of Physics, Soongsil University, Seoul 156-743 (Korea, Republic of); Choi, Jun Woo, E-mail: junwoo@kist.re.kr [Center for Spintronics Research, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Lee, Dong Ryeol, E-mail: drlee@ssu.ac.kr [Department of Physics, Soongsil University, Seoul 156-743 (Korea, Republic of)

2016-03-01

The structural and magnetic properties of Co/C{sub 60}/pentacene and Co/C{sub 60} thin film structures were investigated. Atomic force microscopy and x-ray reflectivity analysis show that the presence or absence of a pentacene buffer layer leads to a highly textured or randomly oriented C{sub 60} layer, respectively. A Co film deposited on a randomly oriented C{sub 60} layer penetrates into the C{sub 60} layer when it is deposited at a slow deposition rate. The Co penetration can be minimized, regardless of the Co deposition rate, by growth on a highly textured and nanostructured C{sub 60}/pentacene layer. Vibrating sample magnetometry measurements show that the saturation magnetization of Co/C{sub 60}/pentacene is significantly reduced compared to that of Co/C{sub 60}. On the other hand, the Co penetration does not seem to have an effect on the magnetic properties, suggesting that the structural properties of the Co and C{sub 60} layer, rather than the Co penetration into the organic C{sub 60} layer, are critical to the magnetic properties of the Co/C{sub 60}. - Highlights: • Structural and magnetic properties of metal(Co)-organic(C{sub 60}) interface is studied. • Highly textured C{sub 60} layer was grown on a pentacene buffer layer (C{sub 60}/pentacene). • Co penetration into the C{sub 60} is significantly suppressed in Co/C{sub 60}/pentacene. • The Co magnetization in Co/C{sub 60}/pentacene is reduced than that in Co/C{sub 60}.

Survival and renewal of murine stem Spermatogonia following 60Co radiation

International Nuclear Information System (INIS)

Erickson, B.H.

1981-01-01

Spermatogonia, with the exception of the few that are either isolated or paired, exist in clones of varying size, and even though the spermatogonium has been the object of much study, our understanding of the radioresponse of the components of this triumvirate is incomplete. Isolated, paired, and clonal spermatogonia are distinguished most reliably when viewed in segments of seminiferous tubules mounted in toto. Tubular segments were isolated from the testes of 80- to 90-day-old BALB/c mice following irradiation doses of 25 to 800 rad and intervals of 1 to 14 days. Neither isolated nor paired spermatogonia were apparently affected by doses up to 200 rad. In contrast the population of A 1 -spermatogonial clones was markedly reduced by a dose of 25 rad. The D 0 and n for the clone were 217 rad and 0.5, respectively. In the apparent absence of a significant elevation in necrosis at doses of 20 rad and less, the loss of A 1 clones was attributed to mitotic inhibition. The comparative unresponsiveness of the isolated spermatogonium to irradiation, its low mitotic rate when contrasted with the clone's high radiosensitivity and mitotic activity, and its apparent ability to excise an abnormal cell and otherwise fragment to give rise to additional clones led to the tentative conclusion that the clone, and not the isolated spermatogonium, is the stem cell

Fractionated x-radiation damage to developing ovaries in the Bonnet Monkey (Macaca radiata)

International Nuclear Information System (INIS)

Andersen, A.C.; Hendrickx, A.G.; Momeni, M.H.

1977-01-01

Fractionated x-ray exposures of 11.5 rad each (total 200 rad) given twice weekly between 77 and 133 days postcoitum severely damaged the ovaries of eight out of nine fetal bonnet monkeys. This radiation regimen reduced follicle counts by 75% or more

Effects of 60Co γ-ray irradiation on human platelets

International Nuclear Information System (INIS)

Wu Guoxin; Zhao Yiming; Ruan Changgeng

1991-02-01

Human platelet-rich plasma was irradiated with various doses (0,1.25,2.5,5.0,10,20,40Gy) of 60 Co γ-ray so as to observing the changes of metabolites and releasing substances of platelets. Alpha-granule membrane protein (GMP-140) molecules on the surface of platelet was expressed significantly increasing when the dosage of 60 Co γ-ray was 5 Gy; however, the glycoprotein (GP) I b and III a was not changed significantly; thromboxane B 2 production in plasma was significantly elevated while the γ-ray was only 2.5 Gy; the concentration of von Willebrand factor was increased when the γ-ray was over 5 Gy, this is in accordance with the GMP-140 molecules. These results indicate that platelets could be activated in vitro when the dosage of 60 Co γ was over 5 Gy

Cytogenetic effects of protracted exposures to alpha-particles from plutonium-239 and to gamma-rays from cobalt-60 compared in male mice

International Nuclear Information System (INIS)

Searle, A.G.; Beechey, C.V.; Green, D.; Humphreys, E.R.

1976-01-01

Adult C3HX 101 hybrid male mice were injected intravenously with 4 μCi of 239 Pu citrate per kg body weight and examined for evidence of cytogenetic damage to the testis after exposures of 21, 28 and 34 weeks, with average doses from α-particles estimated as 13, 18 and 18 rad respectively (mean dose rate 0.00006 rad/min). Results were compared with those obtained when equivalent males were exposed continuously and concurrently to 1128 rad 60 Co γ-irradiation over 28 weeks (0.004 rad/min) The following estimates of the relative effectiveness of the α-and γ-radiation were made: 24 for reciprocal translocations and for chromosome fragments, 22 for dominant lethal mutations acting after implantation. These values (with mean of 23) are based on average testis doses, with no correction for probable non-homogeneity of α dose distribution. In the mice exposed to γ-irradiation, there were significant reductions in testis mass and epididymal sperm-count

Gamma irradiation up to 109 rads of all silica fibers, comparison with polymer clad silica fibers and solid sample between 0.4 and 2.5 micrometers

International Nuclear Information System (INIS)

Boisde, G.; Bonnejean, C.; Perez, J.J.; Neumann, V.; Wurier, B.; Boucher, D.

1983-05-01

The effect of γ radiation (Co 60 ) on optical fibers is studied for investigations to remote measurement in irradiating environments. The spectral characteristics of PCS and AS silica fibers, PCS ''Wet'' and AS ''wet'' and ''superwet'' are compared. An automatic computerized system for measurement ''in situ'' is used between 0,4 AND 1,1 micron. Radiation-induced effects are examined at 840nm on PCS, AS with silicone, AS with epoxy (200 and 400/600μm) up to 5.10 8 rads. Samples of ''dry'', ''wet'', ''superwet'' and ''doped fluor'' silica are studied up to 1,3.10 9 rads between 0,3 and 2,5 μm. The photobleaching, the radiation hardening and the breakeage of PCS and AS-silicone after 10 7 rads are recognized. The spectral characteristics of a band at 610-630nm, a spectral deformation at 945nm for ''wet'' fibers and a peak of the radiation-induced attenuation are observed. The kinetic of the 630nm defect in silica fibers and silica samples is also investigated [fr

Evaluation of radiation protection after the alteration of 60Co irradiation equipment and the augmentation of 60Co load volume

International Nuclear Information System (INIS)

Shi Hongfu

1990-01-01

In order to carry out the irradiation sterilization of medical devices, the authors have augmented the 60 Co load volume to 2.32 pBq, improved the properties of the radiation field and altered the radiation room. All these changes have been checked and accepted by the authorities concerned of Jiangsu Province and Suzhou City. The alteration increases safety and improves the uniformity of high-range dose distribution in the radiation field. The uniformity turns from the original 1.95 to the present 1.34 within the height of 2000 mm from the ground surface and thus can be compared with that of automatic irradiation conveyor abroad. The alteration makes it possible to carry out irradiation treatment of industrial scale by means of 60 Co irradiation equipment designed for biomedial experiments

The rad2 mutation affects the molecular nature of UV and acridine-mustard-induced mutations in the ADE2 gene of Saccharomyces cerevisiae

International Nuclear Information System (INIS)

Ivanov, E.L.; Kovaltzova, S.V.; Kassinova, G.V.; Gracheva, L.M.; Korolev, V.G.; Zakharov, I.A.

1986-01-01

The authors have studied the molecular nature of ade2 mutations induced by UV light and bifunctional acridine-mustard (BAM) in wild-type (RAD) and in excision-deficient (rad2) strains of the yeast, Saccharomyces cerevisiae. In the RAD strain, UV causes 45% GC → AT transitions among all mutations; in the rad2 strain this value is 77%. BAM was shown to be highly specific for frameshift mutagenesis: 60% frameshifts in the RAD strain, and as many as 84% frameshifts in the rad2 strain were induced. Therefore, the rad2 mutation affects the specificity of UV- and BAM-induced mutagenesis in yeast. Experimental data agree with the view that the majority of mutations in the RAD strain are induced by a prereplicative mechanism, whereas mutations in the rad2 strain are predominantly postreplicative events. (Auth.)

Rad9 contribution to radiosensitivity and the G2 checkpoint in a DT40 cell line

Energy Technology Data Exchange (ETDEWEB)

Kumano, Tomoyasu [Kanazawa Univ. (Japan). Graduate School of Medical Science

2002-12-01

In fission yeast, the rad9 (radiation sensitive) gene was cloned from a mutant that is sensitive to ionizing radiation, ultraviolet and hydroxyurea. This gene has also been shown to be required for a DNA damage checkpoint. Orthologues of the rad9 gene have recently been identified in higher eukaryote cells including human. Here we generated Rad9 knockout (Rad9-/-) cells from the chicken B lymphocyte line DT40 to examine the role of Rad9 in higher eukaryotes. First we isolated a part of the chicken Rad9 gene which was 54% identical with human Rad9 at the amino acid sequence level. Next we isolated genomic clones, determined exons and introns, and constructed targeting vectors designed to disrupt exon 1-3 of the chicken Rad9 gene by replacement with a drug-resistant gene. Successful targeted integration was verified by Southern blot analysis and the disruption of the Rad9 gene was confirmed by reverse transcription polymerase chain reaction (RT-PCR). To analyze the radiosensitivity of these Rad9-/- cells, we monitored the clonogenic survival after various degrees of X-ray irradiation. Rad9-/- cells were more sensitive to X-rays than wild type cells at all dosages. However, these cells were less sensitive than ATM knockout (ATM-/-) cells that are known to be X-ray sensitive and that showed a defective checkpoint control. In contrast, Rad9-/- cells were markedly more sensitive to ultraviolet and hydroxyruea. In addition, we assessed the G2 checkpoint by measurement of the mitotic index that is the fraction of the accumulating number of cells in mitosis at various times after X-ray irradiation. While the number of mitotic wild type cells did not increase until 2 hrs after X-ray irradiation, the number of mitotic Rad9-/- cells showed an increase similar to that of ATM-/- cells. These results suggest that just as in fission yeast, in higher eukaryotes Rad9 also contributes to X-ray, ultraviolet and hydroxyurea sensitivity, and plays an important role in the G2 checkpoint

Rad9 contribution to radiosensitivity and the G2 checkpoint in a DT40 cell line

International Nuclear Information System (INIS)

Kumano, Tomoyasu

2002-01-01

In fission yeast, the rad9 (radiation sensitive) gene was cloned from a mutant that is sensitive to ionizing radiation, ultraviolet and hydroxyurea. This gene has also been shown to be required for a DNA damage checkpoint. Orthologues of the rad9 gene have recently been identified in higher eukaryote cells including human. Here we generated Rad9 knockout (Rad9-/-) cells from the chicken B lymphocyte line DT40 to examine the role of Rad9 in higher eukaryotes. First we isolated a part of the chicken Rad9 gene which was 54% identical with human Rad9 at the amino acid sequence level. Next we isolated genomic clones, determined exons and introns, and constructed targeting vectors designed to disrupt exon 1-3 of the chicken Rad9 gene by replacement with a drug-resistant gene. Successful targeted integration was verified by Southern blot analysis and the disruption of the Rad9 gene was confirmed by reverse transcription polymerase chain reaction (RT-PCR). To analyze the radiosensitivity of these Rad9-/- cells, we monitored the clonogenic survival after various degrees of X-ray irradiation. Rad9-/- cells were more sensitive to X-rays than wild type cells at all dosages. However, these cells were less sensitive than ATM knockout (ATM-/-) cells that are known to be X-ray sensitive and that showed a defective checkpoint control. In contrast, Rad9-/- cells were markedly more sensitive to ultraviolet and hydroxyruea. In addition, we assessed the G2 checkpoint by measurement of the mitotic index that is the fraction of the accumulating number of cells in mitosis at various times after X-ray irradiation. While the number of mitotic wild type cells did not increase until 2 hrs after X-ray irradiation, the number of mitotic Rad9-/- cells showed an increase similar to that of ATM-/- cells. These results suggest that just as in fission yeast, in higher eukaryotes Rad9 also contributes to X-ray, ultraviolet and hydroxyurea sensitivity, and plays an important role in the G2 checkpoint

Cellular Dynamics of Rad51 and Rad54 in Response to Postreplicative Stress and DNA Damage in HeLa Cells.

Science.gov (United States)

Choi, Eui-Hwan; Yoon, Seobin; Hahn, Yoonsoo; Kim, Keun P

2017-02-01

Homologous recombination (HR) is necessary for maintenance of genomic integrity and prevention of various mutations in tumor suppressor genes and proto-oncogenes. Rad51 and Rad54 are key HR factors that cope with replication stress and DNA breaks in eukaryotes. Rad51 binds to single-stranded DNA (ssDNA) to form the presynaptic filament that promotes a homology search and DNA strand exchange, and Rad54 stimulates the strand-pairing function of Rad51. Here, we studied the molecular dynamics of Rad51 and Rad54 during the cell cycle of HeLa cells. These cells constitutively express Rad51 and Rad54 throughout the entire cell cycle, and the formation of foci immediately increased in response to various types of DNA damage and replication stress, except for caffeine, which suppressed the Rad51-dependent HR pathway. Depletion of Rad51 caused severe defects in response to postreplicative stress. Accordingly, HeLa cells were arrested at the G2-M transition although a small amount of Rad51 was steadily maintained in HeLa cells. Our results suggest that cell cycle progression and proliferation of HeLa cells can be tightly controlled by the abundance of HR proteins, which are essential for the rapid response to postreplicative stress and DNA damage stress.

Efficacy of a new fractional CO2 laser in the treatment of photodamage and acne scarring.

Science.gov (United States)

Katz, Bruce

2010-01-01

This study evaluates the efficacy and safety of a novel fractional CO(2) laser device for improving facial rhytids, hyperpigmentation, enlarged pores, skin laxity, and acne scarring. Subjects (n= 15) were treated three to five times at 3-week intervals. Biopsy specimens were used to evaluate healing response and neocollagenesis. Clinical improvement was rated on a quartile rating scale from digital photographs. Subject discomfort during treatment was evaluated on a scale of 0 to 5. Fourteen subjects who completed the study achieved good to excellent improvement in overall appearance, with 60% rated excellent. Improvement in photodamage was good to excellent in 92% of subjects, and reduction in rhytids was good to excellent in 85%. A total of 79% of subjects achieved good to excellent improvement in pore sizes and skin laxity. Subject discomfort during treatment was 3.0 +/- 0.7. Erythema persisted for 2-3 days, and subjects resumed normal activities 1-2 days after the procedure. Histological slides after a single treatment showed new collagen formation. The SmartSkin fractional CO(2) system (Cynosure, Inc., Westford, MA, USA) provides significant improvement for the treatment of facial wrinkles, hyperpigmentation, pore size, and skin laxity associated with photodamage.

Improvement of hydrodenitrogenation (HDN) in co-refining of coal-derived liquid and petroleum fraction

Energy Technology Data Exchange (ETDEWEB)

Machida, M.; Ono, S. [Idemitsu Kosan Co. Ltd., Tokyo (Japan); Hattori, H. [Hokkaido University, Sapporo (Japan). Center for Advanced Research of Energy Technology

1997-09-01

The improvement in hydrodenitrogenation (HDN) of coal-derived liquids by co-refining with a petroleum fraction results principally from lowering the nitrogen content of the feedstock (coal-derived liquid) by blending with a nitrogen-free petroleum fraction. Effects of different fractions of coal-derived liquids on HDN and hydrodeoxygenation (HDO) were also examined. The HDN improvement by co-refining could be interpreted in terms of Langmuir-Hinshelwood mechanism. 38 refs., 3 figs., 3 tabs.

Therapeutic Effect of Fractionated Ultra-Pulse CO2 Laser and Fractionated Er∶YAG Laser on Enlarged Facial Pores: an Observation and Comparison%点阵式超脉冲CO2激光和点阵式Er∶YAG激光治疗面部毛孔粗大的疗效比较

Institute of Scientific and Technical Information of China (English)

张元文; 靳贺; 罗世兰; 陈永新; 王娅; 潘文东

2017-01-01

Objective To observe and compare the clinic efficacy and operation safety of fractionated ultra-pulse CO2 laser and fractionated Er ∶ YAG laser in the treatment of enlarged facial pores.Methods Totally 60 patients with enlarged facial pores were divided into two groups randomly:30 of them were treated with fractionated ultrapulse CO2 laser and the rest with fractionated Er ∶ YAG laser.During the follow-up conducted 3 months after the treatment,the clinical improvement was evaluated with a photographic scale for grading the widening of pores,and the adverse reaction was assessed.Results After the treatment,the improvement in the appearance of facial pores was distinctive (P ＜ 0.05) in each group.The difference between the fractionated ultra-pulse CO2 laser group and fractionated Er∶ YAG laser group in clinic efficacy was statistically significant (P ＜ 0.05).The patients'satisfaction rate was 83.3％ for the fractionated ultrapulse CO2 laser group and 90.0％ for the fractionated Er∶YAG laser group.The adverse events were limited to transient pain,erythema,edema and crust desquamates.No permanent hyperpigmentation,hypopigmentation or scar was observed.Conclusions Both fractionated ultra-pulse CO2 laser and fractionated Er∶YAG laser may shrink enlarged facial pores effectively with minimal side effects.%目的 比较点阵式超脉冲CO2激光与点阵式Er∶YAG激光治疗面部毛孔粗大的疗效及安全性.方法 面部毛孔粗大患者60例,随机分为两组,每组30例,分别采用点阵式CO2激光与点阵式Er∶ YAG激光治疗.疗程结束后随访3个月,应用面部毛孔标准照片评价法进行临床疗效评估并比较两组疗效.结果 点阵CO2激光组治疗前与治疗后3个月患者面部毛孔标准照片评分分别为(4.97 ±0.77)和(2.00 ±0.95),点阵Er∶YAG激光组分别为(5.03 ±0.77)和(2.40±0.82),组内比较治疗前后差异具有统计学意义(P＜0.05).组间比较点阵CO2�

NMR-ON on 60CoCo(fcc, hcp, thin film), 52MnCo(fcc), and 90NbCo(fcc)

International Nuclear Information System (INIS)

Zech, E.; Hagn, E.; Ernst, H.; Eska, G.

1978-01-01

With the NMR-ON method the magnetic hyperfine splitting constant of dilute impurities in a ferromagnetic host material (Fe, Ni, Co) can be determined with high accuracy (10 -3 ...10 -4 ). Only few NMR-ON experiments with Co as host lattice have been performed up to now. In constrast to Fe and Ni, two stable modifications exist for Co (fcc and hcp). In the hcp case the magnetic hyperfine field is expected to be anisotropic. Due to the electric field gradient, which is present in this case, a (small) guadrupole interaction is superimposed to the magnetic hyperfine interaction. For 60 CoCo measurements were done on a fcc foil, a hcp single crystal, and on thin films, which were prepared by evaporating Co into glass. For 52 MnCo and 90 NbCo measurements were performed for fcc Co. (Auth.)

Stage, tumor growth rate and optimal dose fractionation schedules in the treatment of squamous cell carcinoma of the head and neck

International Nuclear Information System (INIS)

Sugawara, Tadashi; Morita, Mamoru; Aihara, Toshinori; Tanaka, Osamu

1983-01-01

In 77 patients with cancer of the head and neck, 45 patients received radiotherapy alone, while 32 patients with T 1 or T 2 glottic cancer received combined therapy with laryngomicrosurgery performed prior to or during the course of irradiation. These T 1 and T 2 groups were separately analyzed from other T 1 and T 2 groups as T sub(LMS). Local recurrence rates were compared concerning overall time and fraction size in following three subgroups, i.e., T sub(LMS), Tsub(1+2), and Tsub(3+4). No significant correlation was detected between total dose converted to partial tolerance (PT) and local control in all subgroups except for Tsub(3+4), in which local recurrence rate was rather higher in high PT range. Local control was significantly dependent on overall treatment time and fraction size, differently by tumor stage. Favorable fractionation schedules considered as optimal for T sub(LMS) were those in which treatment was given 5 times weekly with a daily dose rate more than 196 rad in a shorter overall time of less than 42 days. In contrast to T sub(LMS), effective schedules for Tsub(3+4) consisted of longer overall time of more than 60 days and a lower daily dose rate of less than 153 rad. In Tsub(1+2), the optimal schedule was needed to be altered according to rapidness of progression of disease characterised by duration of the complaints, which was statistically proved to be significantly shorter in Tsub(1+2) than Tsub(3+4). Rapidity-adjusted schedule consisted of a shorter over-all time of less than 49 days with a daily dose rate of more than 175 rad 5 fractions a week for a case having a duration of complaints of less than 2.9 months, and a longer overall time of more than 50 days with a daily dose rate of less than 174 rad for a case having a duration of more than 3 months. (J.P.N.)

Fractional CO2 lasers contribute to the treatment of stable non-segmental vitiligo.

Science.gov (United States)

Yuan, Jinping; Chen, Hongqiang; Yan, Ru; Cui, Shaoshan; Li, Yuan-Hong; Wu, Yan; Gao, Xing-Hua; Chen, Hong-Duo

2016-12-01

Stable non-segmental vitiligo is often resistant to conventional therapies. The purpose of this study was to investigate the effect of three types of fractional lasers in the treatment of stable non-segmental vitiligo. Twenty patients were enrolled in the study. The vitiligo lesions of each patient were divided into four treatment parts, and all parts were treated with narrowband ultraviolet-B (NB-UVB). Three of the four parts were respectively treated with three types of fractional lasers (two ablative 10,600-nm CO 2 lasers and one non-ablative 1,565-nm laser), followed by topical betamethasone solution application. The treatment period lasted six months. Efficacy and satisfaction were respectively assessed by dermatologists and patients. The ablative CO 2 lasers, in combination with topical betamethasone solution and NB-UVB, achieved marked to excellent improvement on white patches assessed by dermatologists. Patients showed high satisfaction scores for the treatments. The non-ablative 1,565-nm fractional laser did not provide any further benefit in the treatment of vitiligo. No severe adverse events developed for any of the treatments. The treatment protocol with ablative CO 2 lasers, in combination with topical betamethasone solution and NB-UVB, was suitable for stable non-segmental vitiligo. For vitiligo, the ablative fractional CO 2 laser is more effective than the non-ablative fractional laser.

Seasonal dynamics of Co60 accumulation by Elodea canadensis Rich

International Nuclear Information System (INIS)

Bochenin, V.F.; Chebotina, M.Ya.

1975-01-01

The seasonal dynamics of Co 60 accumulation by one of the most widely distributed fresh-water plants, elodea (Elodea canadensis Rich), were studied. Accumulation was shown to vary with the season. A very low coefficient of accumulation (500-700 units) was typical for the summer period (June to August). It increased in the fall, reached its highest values (3500-4000) in mid-winter (January), and dropped sharply in the spring. Radioisotope concentrations in the plant varied similarly. The cumulative capacity of plants for Co 60 may vary by a factor of 6 to 7 during the year. It is suggested that the seasonal changes in Co 60 accumulation may be caused by both differences in the physiological state of the plants at different times of the year, and by seasonal variations in the hydrochemical regime of the water reservoir. Experiments were done to clarify which of these mechanisms is the determining factor. (V.A.P.)

Experimental study of half-life determinations using 60Co

International Nuclear Information System (INIS)

Rutledge, A.R.; Smith, L.V.; Merritt, J.S.

1983-01-01

The half-life of 60 Co was determined by two methods, (i) the 4π#betta# ionization chamber method and (ii) the 4π #betta#-#betta# coincidence method. The first is a relative counting method in which the only rate-dependent correction is for background, whereas the second is an 'absolute' counting method which involves several rate-dependent corrections. In addition, various methods of calculation of the results were tested. The half-life values for the two counting systems were in good agreement and the weighted mean value for the half-life of 60 Co was found to be 1925.02+-0.47 d. (orig.)

Method of suppressing the deposition of Co-60 to primary coolant pipeways in a nuclear reactor

International Nuclear Information System (INIS)

Hoshi, Michio; Tachikawa, Enzo; Goto, Satoshi; Sagawa, Chiaki; Yonezawa, Chushiro.

1987-01-01

Purpose: To suppress the deposition of Co-60 to primary coolant pipeways in a nuclear reactor. Method: To reduce the accumulation of Co-60 by causing chemical species of extremely similar chemical property with soluble Co-60 to be present together in coolants and replacing the deposition of Co-60 to the primary coolant pipeways in a nuclear reactor with that of the coexistent chemical spacies. Ni or Zn is used as the coexistet chemical spacies of similar chemical property with Co-60. The coexistent amount is from 5 to 10 times of the soluble Co-60 in the primary coolants. Ni or Zn solution adjusted with concentration is poured into and mixed with the coolants from a water feed source by using a high pressure constant volume pump. The amount of Co-60 taken into the pipeways caused by corrosion due to high temperature coolant is reduced to about 1/5 as compared with the case of Co-60 alone if 1 ppb of soluble Co-60 is present in water and 5 ppb of soluble Ni or Zn is added and, reduced to 1/12 if the amount of Ni or Zn is 10 ppb. (Kamimura, M.)

The effect of 60Co γ-radiation and hydroxyurea on the in vivo chain growth of DNA in crypt cells of the small intestine of the mouse

International Nuclear Information System (INIS)

Johanson, K.J.; Rydberg, B.

1977-01-01

DNA chain growth has been studied in small intestinal crypt cells of the mouse in vivo using a sensitive method. The method was designed primarily to study radiation-induced DNA-breaks and their repair; but since there were breaks in DNA at the replicating fork, it was also possible to study DNA chain growth after a 3 H-thymidine pulse. It was found that DNA chain growth was not depressed by 200 rad of 60 Co γ-radiation. This finding supports the hypothesis that irradiation interferes mainly with the initiation of new replicons in mammalian cells affecting DNA chain growth only at higher doses. Hydroxyurea at sufficient dosage, however, depressed or even stopped DNA chain growth in mouse crypt cells in vivo. (author)

Necrosis of the femoral head after /sup 60/Co radiation therapy

Energy Technology Data Exchange (ETDEWEB)

Maruno, H; Kawai, K [Kobe Univ. (Japan). School of Medicine

1978-10-01

A patient (50-year-old woman) received 10500 rad of skin dose and 630 rad of tumor dose for treatment of cervical cancer 15 years ago. The depth dose at the hip-joint was 3590 rad at the right hip-joint and 4315 rad at the left. Hip-joint pain occurred about 15 years after the irradiation, and one more year later she could not walk because of severe pain. X-ray films revealed great bone destruction at the both hip-joints as well as necrosis of the femoral head and arthropathy. The same findings were seen at the ilium, ischium, and pubis. Histologically, the synovial membrane was highly thick, fibrotic, and cicatricial. Obstructive changes were observed also in the small arteries. A severe narrowing or obstruction was observed in the Harversian canal at the bone cortex. The femoral head at the whole area was necrotic. The trabeculae were entirely thinned and were partially thickened by appositional bone formation. This new bone was also necrotic. Edematous fibrous-fatty tissues predominated the bone marrow. There was no proliferation of fibrous cell or new bone formation at the sites other than the margin.

The SRS2 suppressor of rad6 mutations of Saccharomyces cerevisiae acts by channeling DNA lesions into the RAD52 DNA repair pathway

International Nuclear Information System (INIS)

Schiestl, R.H.; Prakash, S.; Prakash, L.

1990-01-01

rad6 mutants of Saccharomyces cerevisiae are defective in the repair of damaged DNA, DNA damage induced mutagenesis, and sporulation. In order to identify genes that can substitute for RAD6 function, the authors have isolated genomic suppressors of the UV sensitivity of rad6 deletion (rad6Δ) mutations and show that they also suppress the γ-ray sensitivity but not the UV mutagenesis or sporulation defects of rad6. The suppressors show semidominance for suppression of UV sensitivity and dominance for suppression of γ-ray sensitivity. The six suppressor mutations they isolated are all alleles of the same locus and are also allelic to a previously described suppressor of the rad6-1 nonsense mutation, SRS2. They show that suppression of rad6Δ is dependent on the RAD52 recombinational repair pathway since suppression is not observed in the rad6Δ SRS2 strain containing an additional mutation in either the RAD51, RAD52, RAD54, RAD55 or RAD57 genes. Possible mechanisms by which SRS2 may channel unrepaired DNA lesions into the RAD52 DNA repair pathway are discussed

/sup 60/Co accumulation by freshwater plants under natural conditions

Energy Technology Data Exchange (ETDEWEB)

Trapeznikov, A V; Trapeznikova, V N [AN SSSR, Sverdlovsk. Inst. Ehkologii Rastenij i Zhivotnykh

1979-03-01

In search for effective bioindicators of radioactive contamination of cooler-reservoirs in atomic power plants the accumulation of /sup 60/Co by four species of higher aquatic plants most widely distributed in the Urals was studied, namely by Elodea canadensis, Ceratophyllum demersum, Lemna minor and Potamogeton pectinatus. It is shown that such plants as Ceratophyllum demersum and Elodea canadensis having the accumulation coefficients of /sup 60/Co 33,500 and 21,500, respectively, can be recommended as bioindicators of this radionuclide in reservoirs contaminated with radioactive cobalt.

On 60Co accumulation by freshwater plants under natural conditions

International Nuclear Information System (INIS)

Trapeznikov, A.V.; Trapeznikova, V.N.

1979-01-01

In search for effective bioindicators of radioactive contamination of cooler-reservoirs in atomic power plants the accumulation of 60 Co by four species of higher aquatic plants most widely distributed in the Urals was studied, namely by Elodea canadensis, Ceratophyllum demersum, Lemna minor and Potamogeton pectinatus. It is shown that such plants as Ceratophyllum demersum and Elodea canadensis having the accumulation coefficients of 60 Co 33,500 and 21,500, respectively, can be recommended as bioindicators of this radionuclide in reservoirs contaminated with radioactive cobalt

Overexpressed of RAD51 suppresses recombination defects: a possible mechanism to reverse genomic instability

Energy Technology Data Exchange (ETDEWEB)

Schild, David; Wiese, Claudia

2009-10-15

RAD51, a key protein in the homologous recombinational DNA repair (HRR) pathway, is the major strand-transferase required for mitotic recombination. An important early step in HRR is the formation of single-stranded DNA (ss-DNA) coated by RPA (a ss-DNA binding protein). Displacement of RPA by RAD51 is highly regulated and facilitated by a number of different proteins known as the 'recombination mediators'. To assist these recombination mediators, a second group of proteins also is required and we are defining these proteins here as 'recombination co-mediators'. Defects in either recombination mediators or comediators, including BRCA1 and BRCA2, lead to impaired HRR that can genetically be complemented for (i.e. suppressed) by overexpression of RAD51. Defects in HRR have long been known to contribute to genomic instability leading to tumor development. Since genomic instability also slows cell growth, precancerous cells presumably require genomic restabilization to gain a growth advantage. RAD51 is overexpressed in many tumors, and therefore, we hypothesize that the complementing ability of elevated levels of RAD51 in tumors with initial HRR defects limits genomic instability during carcinogenic progression. Of particular interest, this model may also help explain the high frequency of TP53 mutations in human cancers, since wild-type p53 represses RAD51.

Coordination of Rad1-Rad10 interactions with Msh2-Msh3, Saw1 and RPA is essential for functional 3' non-homologous tail removal.

Science.gov (United States)

Eichmiller, Robin; Medina-Rivera, Melisa; DeSanto, Rachel; Minca, Eugen; Kim, Christopher; Holland, Cory; Seol, Ja-Hwan; Schmit, Megan; Oramus, Diane; Smith, Jessica; Gallardo, Ignacio F; Finkelstein, Ilya J; Lee, Sang Eun; Surtees, Jennifer A

2018-04-06

Double strand DNA break repair (DSBR) comprises multiple pathways. A subset of DSBR pathways, including single strand annealing, involve intermediates with 3' non-homologous tails that must be removed to complete repair. In Saccharomyces cerevisiae, Rad1-Rad10 is the structure-specific endonuclease that cleaves the tails in 3' non-homologous tail removal (3' NHTR). Rad1-Rad10 is also an essential component of the nucleotide excision repair (NER) pathway. In both cases, Rad1-Rad10 requires protein partners for recruitment to the relevant DNA intermediate. Msh2-Msh3 and Saw1 recruit Rad1-Rad10 in 3' NHTR; Rad14 recruits Rad1-Rad10 in NER. We created two rad1 separation-of-function alleles, rad1R203A,K205A and rad1R218A; both are defective in 3' NHTR but functional in NER. In vitro, rad1R203A,K205A was impaired at multiple steps in 3' NHTR. The rad1R218A in vivo phenotype resembles that of msh2- or msh3-deleted cells; recruitment of rad1R218A-Rad10 to recombination intermediates is defective. Interactions among rad1R218A-Rad10 and Msh2-Msh3 and Saw1 are altered and rad1R218A-Rad10 interactions with RPA are compromised. We propose a model in which Rad1-Rad10 is recruited and positioned at the recombination intermediate through interactions, between Saw1 and DNA, Rad1-Rad10 and Msh2-Msh3, Saw1 and Msh2-Msh3 and Rad1-Rad10 and RPA. When any of these interactions is altered, 3' NHTR is impaired.

Regulation of Rad51-Mediated Homologous Recombination by BRCA2, DSS1 and RAD52

DEFF Research Database (Denmark)

Rants, Louise Olthaver Juhl

Homologous recombination (HR) provides a mechanism to restore integrity and maintain stability of the genetic material. HR is a major pathway for repair of DNA double-strand breaks (DSB), recovery of broken replication forks and generation of meiotic crossovers. The defining step in HR is homolog......Homologous recombination (HR) provides a mechanism to restore integrity and maintain stability of the genetic material. HR is a major pathway for repair of DNA double-strand breaks (DSB), recovery of broken replication forks and generation of meiotic crossovers. The defining step in HR...... is homologous strand exchange directed by the RecA-related recombinase Rad51. BRCA2 participates in HR by mediating Rad51 homology-directed repair. Both BRCA2 and Rad51 are essential for HR, DNA repair, and the maintenance of genome stability. In the present study, we seek to understand the mechanism of BRCA2...... with RAD52-mediated repair at sites of CPT-induced DNA damage. The synthetic lethality approach using RAD52 small molecule inhibitors in brca-deficient cancers is a promising therapeutic strategy for cancer treatment....

Development of irradiator {sup 60}Co sources

Energy Technology Data Exchange (ETDEWEB)

Mosca, Rodrigo C.; Moura, Eduardo S.; Zeituni, Carlos A.; Mathor, Monica B., E-mail: rcmosca@usp.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2011-07-01

According to a recent report by the International Agency for Research on Cancer (IARC) / WHO (2008-2010), the global impact of cancer more than doubled in 30 years. In this report, it was estimated that occurred about 12 million new cancer cases and 7 million deaths. In Brazil in 2010, with estimates for the year 2011, point to the occurrence of 489,270 new cases of cancer. Among the possibilities for cancer treatment, radiotherapy is one of the most important therapeutic and resources used to combat it. However, inherent complications of treatment can occur such as tiredness, loss of appetite, radiodermatitis and in more extreme cases late radionecrosis. In order to reproduce a point of radionecrosis in the vicinity of radiodermatitis to mimic these effects in animals, producing a model for assessment of tissue repair, we propose the setting up of an irradiator source of collimated {sup 60}Co. The development of was based on 11 sources of {sup 60}Co with 1 mm thickness that were inserted by inference in stainless steel 'gate-source' screw (patent pending) and later adjusted in a cross-shaped arrangement reinforced so that the beam radiation is directed to a target point, saving for other regions around this target point. The main use of this irradiator with sources of {sup 60}Co is just one cause radionecrosis point (target point) of approximately 5 mm{sup 2} with a surrounding and adjacent area of radiodermatitis around about 8 to 10 mm{sup 2} in laboratory animals for subsequent coating with epidermal-dermal matrix populated by a cell culture of human fibroblasts, keratinocytes and mesenchymal stem cells. With that said, its use will be valuable for evaluation of curative treatments against the bone and radionecrosis or palliative treatment rather than as it is currently assumed. (author)

Clinical efficacy of utilizing Ultrapulse CO2 combined with fractional CO2 laser for the treatment of hypertrophic scars in Asians-A prospective clinical evaluation.

Science.gov (United States)

Lei, Ying; Li, Shi Feng; Yu, Yi Ling; Tan, Jun; Gold, Michael H

2017-06-01

Hypertrophic scarring is seen regularly. Tissue penetration of laser energy into hypertrophic scars using computer defaults from some lasers may be insufficient and penetration not enough. We have developed a treatment with an interrupted laser "drilling" by the Ultrapulse CO 2 (Manual Fractional Technology, MFT) and, a second pass, with fractional CO 2 . The MFT with fractional CO 2 lasers to treat hypertrophic scars is evaluated. A total of 158 patients with hypertrophic scars had three sessions of MFT with fractional CO 2 laser at 3-month intervals. Evaluations made before and 6 months after the 3rd treatment: (1) the Vancouver Scar Scale (VSS), (2) the University of North Carolina (UNC) Scar Scale, and (3) a survey of patient satisfaction. All data were analyzed using a t-test before and after treatment. The VSS score decreased from 9.35 to 3.12 (Plaser drilling by MFT and a fractional CO2 laser had profound effects on the hypertrophic scars treated. It works by increasing the penetration depth of the CO 2 laser in the scar tissue, exerting more precise effects on the hypertrophic scars. MFT combined with fractional CO 2 laser has the potential to be a major advance in the treatment of hypertrophic scars. © 2017 Wiley Periodicals, Inc.

Function of Rad51 paralogs in eukaryotic homologous recombinational repair

International Nuclear Information System (INIS)

Liu, N.; Skowronek, K.

2003-01-01

Full text: Homologous recombinational repair (HRR) is an important mechanism for maintaining genetic integrity and cancer prevention by accurately repair of DNA double strand breaks induced by environmental insults or occurred in DNA replication. A critical step in HRR is the polymerization of Rad51 on single stranded DNA to form nuclear protein filaments, the later conduct DNA strand paring and exchange between homologous strands. A number of proteins, including replication protein A (RPA), Rad52 and Rad51 paralogs, are suggested to modulate or facilitate the process of Rad51 filament formation. Five Rad51 paralogs, namely XRCC2, XRCC3, Rad51B, Rad51C and Rad51D have been identified in eucaryotic cells. These proteins show distant protein sequence identity to Rad51, to yeast Rad51 paralogs (Rad55 and Rad57) and to each other. Hamster or chicken mutants of Rad51 paralogs exhibit hypersensitivity to a variety of DNA damaging agents, especially cross-linking agents, and are defective in assembly of Rad51 onto HRR site after DNA damage. Recent data from our and other labs showed that Rad51 paralogs constitute two distinct complexes in cell extracts, one contains XRCC2, Rad51B, Rad51C and Rad51D, and the other contains Rad51C and XRCC3. Rad51C is involved in both complexes. Our results also showed that XRCC3-Rad51C complex interacts with Rad51 in vivo. Furthermore, overexpression of Rad52 can partially suppress the hypersensitivity of XRCC2 mutant irs1 to ionizing radiation and corrected the defects in Rad51 focus formation. These results suggest that XRCC2 and other Rad51 paralogs play a mediator function to Rad51 in the early stage of HRR

RAD51C germline mutations in breast and ovarian cancer cases from high-risk families.

Directory of Open Access Journals (Sweden)

Jessica Clague

Full Text Available BRCA1 and BRCA2 are the most well-known breast cancer susceptibility genes. Additional genes involved in DNA repair have been identified as predisposing to breast cancer. One such gene, RAD51C, is essential for homologous recombination repair. Several likely pathogenic RAD51C mutations have been identified in BRCA1- and BRCA2-negative breast and ovarian cancer families. We performed complete sequencing of RAD51C in germline DNA of 286 female breast and/or ovarian cancer cases with a family history of breast and ovarian cancers, who had previously tested negative for mutations in BRCA1 and BRCA2. We screened 133 breast cancer cases, 119 ovarian cancer cases, and 34 with both breast and ovarian cancers. Fifteen DNA sequence variants were identified; including four intronic, one 5' UTR, one promoter, three synonymous, and six non-synonymous variants. None were truncating. The in-silico SIFT and Polyphen programs were used to predict possible pathogenicity of the six non-synonomous variants based on sequence conservation. G153D and T287A were predicted to be likely pathogenic. Two additional variants, A126T and R214C alter amino acids in important domains of the protein such that they could be pathogenic. Two-hybrid screening and immunoblot analyses were performed to assess the functionality of these four non-synonomous variants in yeast. The RAD51C-G153D protein displayed no detectable interaction with either XRCC3 or RAD51B, and RAD51C-R214C displayed significantly decreased interaction with both XRCC3 and RAD51B (p<0.001. Immunoblots of RAD51C-Gal4 activation domain fusion peptides showed protein levels of RAD51C-G153D and RAD51C-R214C that were 50% and 60% of the wild-type, respectively. Based on these data, the RAD51C-G153D variant is likely to be pathogenic, while the RAD51C- R214C variant is hypomorphic of uncertain pathogenicity. These results provide further support that RAD51C is a rare breast and ovarian cancer susceptibility gene.

Fetal uptake of 60CoCl2 and 57Co-cyanocobalamin in different gestation stages of rats

International Nuclear Information System (INIS)

Nishimura, Yoshikazu; Inaba, Jiro; Ichikawa, Ryushi

1978-01-01

Fetal uptake of 60 CoCl 2 and 57 Co-cyanocobalamin was investigated in different gestation stages of rats. The fetal uptake of 60 CoCl 2 24 hrs after administration to pregnant rat slightly increased with the progress of gestation age at the administration but taking account of the growth of the fetus the value expressed in terms of concentration of 60 Co 24 hrs after injection decreased on the contrary. In the case of 57 Co-cyanocobalamin the fetal uptake 24 hrs after administration to pregnant rat increased markedly when the time of injection was in later stage of pregnancy. Fetal accumulation of 57 Co-cyanocobalamin increased with time after injection and the retrograde transfer from fetus to mother was not observed. The amount of 57 Co-cyanocobalamin in the placenta is the greatest immediately after administration followed by a gradual decrease thereafter. Since the amount of radiocobalt transferred through placenta in both chemical forms is greater than that accumulated in placenta, this organ does not seem to play a role as a barrier to both forms of radiocobalt. It was observed that 1 - 2% of maternal dose of 57 Co-cyanocobalamin were transferred to sucklings via milk. The amount of milk-born cyanocobalamin in sucklings is dependent on the gestation age at the time of dosing. (author)

Selection of optimum ROI for dual radionuclide analysis of 55Fe-63Ni and 63Ni-60Co

International Nuclear Information System (INIS)

Priya, S.; Prabhath Ravi, K.; Yadav, R.K.B.; Rao, D.D.; Gopalakrishnan, R.K.

2016-01-01

Dual label counting in liquid scintillation counting (LSC) enables simultaneous activity determination of two radionuclides. Dual counting procedure for 3 H and 14 C has been well established. There are several other nuclides like 63 Ni (E β- =67keV), 55 Fe (6 keV X-ray and auger electron) which are often chemically separated using detailed procedures with high decontamination factors (DF) and quantified using LSC. Despite the laborious separations, traces of these nuclides in the chemically separated fractions can mutually make their quantification difficult due to overlap of counts from both radionuclides in the spectrum, which gets further complicated in presence of traces of 60 Co. For dual label counting technique, it is essential to establish the discriminator setting at which there will be spillover of counts from both radionuclides in the two counting regions required for the inclusion method. The objective of the current work is to establish two counting ROI's for dual counting of (i) 63 Ni- 55 Fe and (ii) 63 Ni- 60 Co in a TDCR based LSC system

Detection and thermoluminescence of coriander (Coriandrum sativum L.) irradiated with {sup 60}Co; Deteccion y termoluminiscencia del cilantro (Coriandrum sativum L.) irradiado con {sup 60}Co

Energy Technology Data Exchange (ETDEWEB)

Ruiz G, B. [Departamento de Agricultura y Ganaderia, Universidad de Sonora, 083190 Hermosillo, Sonora (Mexico); Cruz Z, E. [Unidad de Irradiacion y Seguridad Radiologica, Instituto de Ciencias Nucleares, UNAM, A. P. 70-543, 04510 Mexico D. F. (Mexico); Barboza F, M. [Centro de Investigacion en Fisica, Universidad de Sonora, A. P. 5-088, 083190 Hermosillo, Sonora (Mexico)

2009-10-15

The fresh and dried coriander (Coriandrum sativum L.) is a spice of high commercial value as food for consumption in Mexico. Their hygienic quality is often poor due to some factors: contaminants present in irrigation water and the cultivation atmosphere, harvesting and post harvest handling, mainly. The process by radiation is an alternative to achieve the sterilization to adequate dose for the hygienic quality for its consumption. However, irradiation also involves food detection exposed to radiation. This paper presents detected results on the dried coriander that was obtained from fresh samples and thermoluminescent properties such as glow curves structure from low doses (0.5 Gy) to high (15 kGy), the dose response, thermoluminescent signal decay, in order to determine the loss of stability during the storage of the poly mineral fraction. We obtained the inorganic fraction separation of the organic part of particle sizes of 10 {mu}m by the Zimmerman method. The samples were exposed at two dose ranges; 0.5-400 Gy and 0.5-15 kGy of gamma radiation with {sup 60}Co. The limit of thermoluminescent detection of the irradiated coriander samples was from 1 Gy. The glow curves were at a broad band of 35-400 C, with a maximum thermoluminescence around 182-196 C, and run at 164 C for high doses of 15 kGy. The range of linear response to dose was 4-25 Gy, whereas higher doses than the kGy order the response increase with the dose. The thermoluminescent properties of the coriander poly mineral fraction, show it can be used to identify irradiated food at gamma doses relatively low and even in doses of commercial interest due to the high stability of thermoluminescent signals. (Author)

About local fractional three-dimensional compressible Navier-Stokes equations in Cantor-type cylindrical co-ordinate system

Directory of Open Access Journals (Sweden)

Gao Guo-Ping

2016-01-01

Full Text Available In this article, we investigate the local fractional 3-D compressible Navier-Stokes equation via local fractional derivative. We use the Cantor-type cylindrical co-ordinate method to transfer 3-D compressible Navier-Stokes equation from the Cantorian co-ordinate system to the Cantor-type cylindrical co-ordinate system.

Derivation of cell population kinetic parameters from clinical statistical data (program RAD3)

International Nuclear Information System (INIS)

Cohen, L.

1978-01-01

Cellular lethality models generally require up to 6 parameters to simulate a clinical course of fractionated radiation therapy and to derive an estimate of the cellular surviving fraction for a given treatment scheme. These parameters are the mean cellular lethal dose, the extrapolation number, the ratio of sublethal to irreparable events, the regeneration rate, the repopulation limit (cell cycles), and a field-size or tumor-volume factor. A computer program (RAD3) was designed to derive best-fitting values for these parameters in relation to available clinical data based on the assumption that if a number of different fractionation schemes yield similar reactions, the cellular surviving fractions will be about equal in each instance. Parameters were derived for a variety of human tissues from which realistic iso-effect functions could be generated

Sorption of 60 Co in natural zeolite (clinoptilolite)

International Nuclear Information System (INIS)

Hernandez B, E.

1996-01-01

A Mexican zeolite (clinoptilolite) from Taxco, Guerrero, was partially stabilized with sodium cations. Radioactive Cobalt ( 60 Co) was used to study the Co 2+ sorption in the stabilized zeolite (Na + ). It was found that sorption in general does not favour the diffusion of cobalt between framework, it explains because of it is a natural zeolite and its composition heterogeneous decrease its exchange capacity by the generated competence to the existence other type of exchange ions. The cobalt retention reached the highest level, around 0.408 m eq Co 2+ /g in the Na-Clinoptilolite. The crystallinity of the aluminosilicates was maintained during experiments, it was verified by XRD patterns. (Author)

Migration characteristics of cobalt-60 through sandy soil in high pH solution

International Nuclear Information System (INIS)

Ohnuki, Toshihiko

1992-01-01

Migration characteristics of 60 Co through sandy soil in high pH solution has been investigated by both column and batch techniques. The association of 60 Co with the sandy soil and its components were studied by sequential extraction techniques. The concentration profile of 60 Co in the sandy soil column was composed of two exponential curves showing that 60 Co would consist of immobile and mobile fractions. The immobile 60 Co was retained by the sandy soil and was distributed near the top. Though the mobile 60 Co was little sorbed by soil and migrated through the soil column, maximum concentration of 60 Co in the effluents decreased slightly with increasing path length of the soil column. The sequential extraction of 60 Co from the sandy soil and from its components showed that 60 Co was sorbed by both manganese oxide and clay minerals. And manganese oxide is one of the responsible soil components for the observed decrease in the maximum concentration of 60 Co in the effluents. Although the content of manganese oxide in the sandy soil was 0.13%, manganese oxide is the important component to prevent from the migration of 60 Co in the high pH solution. (author)

Quality assurance and accuracy in Co-60 radiotherapy

Energy Technology Data Exchange (ETDEWEB)

Scarlat, F; Rebigan, F

1995-12-01

The characteristics of a set of 88 Co-60 sources ONCOBALT, are described. This set of radioactive sources is an original choice of a variety of cobalt sources in point of physical size and activity. It includes 5 activity groups of cells (stainless steel) among 2 and 12 mCi, 5 and 15 mm active length and 2, 2.5 and 3 mm external diameter, 4 activity groups of needle activities between 1.3 and 3.4 mCi, 15 and 20 mm active length, 1.8 mm external diameter. By an appropriate choice of activities, dimensions and geometry of irradiation we can get an error of max.5% as to the receive dose. The radioactive purity of cobalt is 99.9%. To meet the requirements in practical radiotherapy we checked the Co-60 sources by tests: tight test, mechanical test, corrosion test and contamination test that gave us full satisfaction.

Areal distribution of 60Co, 137Cs, and 90Sr in streambed gravels of White Oak Creek Watershed, Oak Ridge, Tennessee

International Nuclear Information System (INIS)

Cerling, T.E.; Spalding, B.P.

1981-01-01

The concentrations of 90 Sr, 60 Co, and 137 Cs in streambed gravels from contaminated drainages in White Oak Creek Watershed were determined. Methods to determine the relative contributions of various sources to the total discharge from the watershed were developed. Principal sources of 90 Sr were: ORNL plant effluents (50%), leaching from solid waste disposal area (SWDA) 4 (30%), and leaching from SWDA 5 (10%). Minor sources included SWDA 3, the Molten Salt Reactor Facility, and intermediate-level liquid waste pit 1 with each representing 4% or less of the total basin discharge. The cooling water effluent from the High-Flux Isotope Reactor was the dominant source of 60 Co contamination in the watershed. ORNL plant effluents accounted for almost all the 137 Cs discharge from White Oak Creek basin. Downstream radionuclide concentrations were constant until significant dilution by other tributaries occurred. Any future activities giving rise to additional contamination can now be identified. Distribution coefficients between streambed gravels and streamwater for 85 Sr, 60 Co, and 137 Cs were 50, 560, and 8460 ml/g, respectively. An abridged radiochemical fractionation developed for 90 Sr was found to be as accurate and precise for these samples as the standard 90 Sr method above levels of 2 dpm/g

RadCat 2.0 User Guide.

Energy Technology Data Exchange (ETDEWEB)

Osborn, Douglas.; Weiner, Ruth F.; Mills, George Scott; Hamp, Steve C.; O' Donnell, Brandon, M.; Orcutt, David J.; Heames, Terence J.; Hinojosa, Daniel

2005-01-01

This document provides a detailed discussion and a guide for the use of the RadCat 2.0 Graphical User Interface input file generator for the RADTRAN 5.5 code. The differences between RadCat 2.0 and RadCat 1.0 can be attributed to the differences between RADTRAN 5 and RADTRAN 5.5 as well as clarification for some of the input parameters. 3

Functional groups and reactivity of size-fractionated Aldrich humic acid

Energy Technology Data Exchange (ETDEWEB)

Tanaka, Tadao, E-mail: tanaka.tadao26@jaea.go.jp [Nuclear Safety Research Center, Japan Atomic Energy Agency, Shirakata 2-4, Tokai, Naka, Ibaraki, 319-1195 (Japan)

2012-03-20

The complexation affinity of the Aldrich Chemicals humic acid with {sup 60}Co was examined with respect to molecular size of humic acid. Correlations between the affinity and the structures of humic acid were studied. At low humic acid concentration range, {sup 60}Co was interacted with the humic acid of size fraction over 100k Da (HA(100<)). With increasing humic acid concentration, the {sup 60}Co was preferentially interacted with the 30k-100k Da of humic acid (HA(30-100)). Fractionated HA(100<) and HA(30-100) were characterized from their FTIR (Fourier Transform Infra-Red), {sup 13}C NMR spectral analyses and acid-base titration curves. The HA(10<) having aliphatic branched structure, smaller amount of COOH group and large proton exchangeable capacity, seem to show low covalent bonding nature and high ion exchangeability in the complexation. In addition, steric hindrance may affect on the complexation, by winding up like random coils from the branched structure. The HA(30-100) is dominated with the aromatic COOH group and OH group and it may preferentially coordinate to {sup 60}Co by covalent binding. These presumptions were supported by XPS analysis, in which the biding energy of cobalt-humates was discussed.

Final Report for Fractionation and Separation of Polydisperse Nanoparticles into Distinct Monodisperse Fractions Using CO2 Expanded Liquids

Energy Technology Data Exchange (ETDEWEB)

Chistopher Roberts

2007-08-31

The overall objective of this project was to facilitate efficient fractionation and separation of polydisperse metal nanoparticle populations into distinct monodisperse fractions using the tunable solvent properties of gas expanded liquids. Specifically, the dispersibility of ligand-stabilized nanoparticles in an organic solution was controlled by altering the ligand-solvent interaction (solvation) by the addition of carbon dioxide (CO{sub 2}) gas as an antisolvent (thereby tailoring the bulk solvent strength) in a custom high pressure apparatus developed in our lab. This was accomplished by adjusting the CO{sub 2} pressure over the liquid dispersion, resulting in a simple means of tuning the nanoparticle precipitation by size. Overall, this work utilized the highly tunable solvent properties of organic/CO{sub 2} solvent mixtures to selectively size-separate dispersions of polydisperse nanoparticles (ranging from 1 to 20 nm in size) into monodisperse fractions ({+-}1nm). Specifically, three primary tasks were performed to meet the overall objective. Task 1 involved the investigation of the effects of various operating parameters (such as temperature, pressure, ligand length and ligand type) on the efficiency of separation and fractionation of Ag nanoparticles. In addition, a thermodynamic interaction energy model was developed to predict the dispersibility of different sized nanoparticles in the gas expanded liquids at various conditions. Task 2 involved the extension of the experimental procedures identified in task 1 to the separation of other metal particles used in catalysis such as Au as well as other materials such as semiconductor particles (e.g. CdSe). Task 3 involved using the optimal conditions identified in tasks 1 and 2 to scale up the process to handle sample sizes of greater than 1 g. An experimental system was designed to allow nanoparticles of increasingly smaller sizes to be precipitated sequentially in a vertical series of high pressure vessels by

Experimental studies on prevention of trichinosis by food irradiation (Co60)

International Nuclear Information System (INIS)

Shimazu, Kimitaka

1993-01-01

A systemic study was performed to elucidate the effects of 60 Co irradiation on maturation or fecundity of Trichinella spiralis by assessing from parasitological, morphological and immunological points of view. Pieces of muscle tissue of mice infected with T. spiralis were irradiated with 60 Co at doses of 50, 75, 100, 150 and 200 Gy. These irradiated tissue (Experimental group) and non-irradiated tissues (Control group) were fed to healthy mice. Half of the mice were sacrificed 6 days after the ingestion. The number of adult worms were counted and subjected to statistical analysis, which disclosed a good correlation between the dose of 60 Co irradiation and worm damage; the higher the dose the more damage parasites had, and no adults were recovered if the tissue had been irradiated with more than 150 Gy prior to infection. The same tendency was true for the histopathology of the intenstines of host mice; the higher the dose the less tissue damage. Circulating antigens of T. spiralis and antibodies against T. spiralis were detected in every serum examined by ELISA. The remaining mice were sacrificed 30 days after the ingestion. The numbers of muscle larvae were counted and subjected to statistical analysis, which disclosed a good correlation between th dose of 60 Co irradiation and worm damage, and no larvae were recovered if the tissue had been irradiated with more than 75Gy. Higher concentrations of circulating antigens of T. spiralis and antibodies against T. spiralis were detected in the serum samples taken with muscle larvae. Thus this study established that 60 Co irradiation of more than 150 Gy caused complete damage on maturation, and that irradiation of more than 75 Gy caused complete damage on the fecundity of T. spimalis. (author)

Calculational methods for estimating skin dose from electrons in Co-60 gamma-ray beams

International Nuclear Information System (INIS)

Higgins, P.D.; Sibata, C.H.; Attix, F.H.; Paliwal, B.R.

1983-01-01

Several methods have been employed to calculate the relative contribution to skin dose due to scattered electrons in Co-60 gamma-ray beams. Either the Klein-Nishina differential scattering probability is employed to determine the number and initial energy of electrons scattered into the direction of a detector, or a Gaussian approximation is used to specify the surface distribution of initial pencil electron beams created by parallel or diverging photon fields. Results of these calculations are compared with experimental data. In addition, that fraction of relative surface dose resulting from photon interactions in air alone is estimated and compared with data extrapolated from measurements at large source-surface distance (SSD). The contribution to surface dose from electrons generated in air is 50% or more of the total skin dose for SSDs greater than 80 cm

Calculational methods for estimating skin dose from electrons in Co-60 gamma-ray beams

International Nuclear Information System (INIS)

Higgins, P.D.; Sibata, C.H.; Attix, F.H.; Paliwal, B.R.

1983-01-01

Several methods have been employed to calculate the relative contribution to skin dose due to scattered electrons in Co-60 γ-ray beams. Either the Klein--Nishina differential scattering probability is employed to determine the number and initial energy of electrons scattered into the direction of a detector, or a Gaussian approximation is used to specify the surface distribution of initial pencil electron beams created by parallel or diverging photon fields. Results of these calculations are compared with experimental data. In addition, that fraction of relative surface dose resulting from photon interactions in air alone is estimated and compared with data extrapolated from measurements at large source--surface distance (SSD). The contribution to surface dose from electrons generated in air is 50% or more of the total skin dose for SSDs greater than 80 cm

Monte Carlo Dosimetry of the 60Co BEBIG High Dose Rate for Brachytherapy.

Directory of Open Access Journals (Sweden)

Luciana Tourinho Campos

Full Text Available The use of high-dose-rate brachytherapy is currently a widespread practice worldwide. The most common isotope source is 192Ir, but 60Co is also becoming available for HDR. One of main advantages of 60Co compared to 192Ir is the economic and practical benefit because of its longer half-live, which is 5.27 years. Recently, Eckert & Ziegler BEBIG, Germany, introduced a new afterloading brachytherapy machine (MultiSource®; it has the option to use either the 60Co or 192Ir HDR source. The source for the Monte Carlo calculations is the new 60Co source (model Co0.A86, which is referred to as the new BEBIG 60Co HDR source and is a modified version of the 60Co source (model GK60M21, which is also from BEBIG.The purpose of this work is to obtain the dosimetry parameters in accordance with the AAPM TG-43U1 formalism with Monte Carlo calculations regarding the BEBIG 60Co high-dose-rate brachytherapy to investigate the required treatment-planning parameters. The geometric design and material details of the source was provided by the manufacturer and was used to define the Monte Carlo geometry. To validate the source geometry, a few dosimetry parameters had to be calculated according to the AAPM TG-43U1 formalism. The dosimetry studies included the calculation of the air kerma strength Sk, collision kerma in water along the transverse axis with an unbounded phantom, dose rate constant and radial dose function. The Monte Carlo code system that was used was EGSnrc with a new cavity code, which is a part of EGS++ that allows calculating the radial dose function around the source. The spectrum to simulate 60Co was composed of two photon energies, 1.17 and 1.33 MeV. Only the gamma part of the spectrum was used; the contribution of the electrons to the dose is negligible because of the full absorption by the stainless-steel wall around the metallic 60Co. The XCOM photon cross-section library was used in subsequent simulations, and the photoelectric effect, pair

FANCI-FANCD2 stabilizes the RAD51-DNA complex by binding RAD51 and protects the 5′-DNA end

Science.gov (United States)

Sato, Koichi; Shimomuki, Mayo; Katsuki, Yoko; Takahashi, Daisuke; Kobayashi, Wataru; Ishiai, Masamichi; Miyoshi, Hiroyuki; Takata, Minoru; Kurumizaka, Hitoshi

2016-01-01

The FANCI-FANCD2 (I-D) complex is considered to work with RAD51 to protect the damaged DNA in the stalled replication fork. However, the means by which this DNA protection is accomplished have remained elusive. In the present study, we found that the I-D complex directly binds to RAD51, and stabilizes the RAD51-DNA filament. Unexpectedly, the DNA binding activity of FANCI, but not FANCD2, is explicitly required for the I-D complex-mediated RAD51-DNA filament stabilization. The RAD51 filament stabilized by the I-D complex actually protects the DNA end from nucleolytic degradation by an FA-associated nuclease, FAN1. This DNA end protection is not observed with the RAD51 mutant from FANCR patient cells. These results clearly answer the currently enigmatic question of how RAD51 functions with the I-D complex to prevent genomic instability at the stalled replication fork. PMID:27694619

Effect of neutrons with an energy of 0.35 and 0.85 MeV and gamma radiation of 60Co on the organ cultures of the human bone marrow

International Nuclear Information System (INIS)

Zherbin, E.A.; Kolesnikova, A.I.; Konoplyannikov, A.G.; Khoptynskaya, S.K.; Obaturov, G.M.; Kapchigashev, S.P.

1979-01-01

A comparative study of the radiation injury of human hemopoietic cells under the effect of γ radiation of 60 Co in doses from 100 to 1500 rad, 0.85 MeV neutrons in doses from 50 to 600 rad and 0.35 MeV neutrons in doses from 30 to 600 rad was carried out using the method of organic cultivation of bone marrow. Under the effect of the above radiation types, the fissionable granulocytes (promyelocytes and myelocytes) and lymphocytes are most radiosensitive among the 4-day organic cultures. The dose dependence of the decrease in relative and absolute content of these cell forms in the cultures as well as the dose dependence of the decrease in total cell structure in the cultures were revealed. It has been found that the dose dependence for the above tests consists of two components: radiosensitive and radioresistant ones. The radiation doses causing death in 50% of cells in relation to control (D 50 ) were determined. On the bases of D 50 values, the coefficients of relative biological efficiency (RBE) were calculated for 0.85 and 0.35 MeV neutrons. The RBE coefficients are confined in the 1.4-3.4 and 2.4-6.7 intervals respectively. It has been confirmed that 0.35 MeV neutrons are 1.5-2 times more effective than 0.85 MeV neutrons. The coefficients of RBE neutrons calculated for radioresistant cell components are higher than the corresponding values estimated according to D 50 value; in some cases they reach values ranging from 6 to 10

Radiation testing of thick-wall objects using a linear accelerator or Co-60

International Nuclear Information System (INIS)

Depending on the energy required, a 60 Co source or various types of betatrons and linear accelerators may be used for radiation testing of thick-walled metal parts. While 60 Co sources are easily transported, accelerators are not, but a transportable linear accelerator is described

Transport of Co-60 from Argentina to abroad

International Nuclear Information System (INIS)

Cesario, R.; Pinamonti, M.

1993-01-01

The Co-60 bearing wastes from the Embalse Nuclear Power Plant, Argentina are transported to Canada, the United States and Mexico. Ocean transportation, terrestrial transportation, air transportation are applied, and the total activity in bulk material shipped reached 2.96x10 17 Bq. (J.P.N.)

RadCon: A Radiological Consequences Model

International Nuclear Information System (INIS)

Crawford, J.; Domel, R.U.

2000-05-01

RadCon estimates the dose received by user selected groups in the population from an accidental release of radionuclides to the environment. The exposure pathways considered are external exposure from the cloud and ground and internal exposure from inhalation and ingestion of contaminated food. Atmospheric dispersion modelling is carried out externally to RadCon.Given a two dimensional time varying air and ground concentration of radioactive elements, RadCon allows the user to: view the air and ground concentration over the affected area, select optional parameters and calculate the dose to people,display the results to the user, and change the parameter values. RadCon offers two user interfaces: 1) the standard graphical user interface which is started using Java DoseApp at the command line, or by setting up a shortcut to this command (particularly when RadCon is installed on a PC) and 2) the text based interface used to generate information for the model inter-comparison exercise . This is initiated using Java BIOMASS at the command line, or an equivalent shortcut. The text based interface was developed for research purposes and is not generally available. Appendices A, B and C provide a summary of instructions on setting up RadCon. This will generally be carried out by the computer support personnel

Vulcanization of polybutadiene latex induced by 60Co γ-rays irradiation

International Nuclear Information System (INIS)

Liu Yuguang; Huang Yudong; Hou Jing; Gao Deyu; Zhang Xuequan

2007-01-01

Fully vulcanized polybutadiene rubber particles (FVBR) were prepared by polybutadiene latex (PBL) vulcanization induced by 60 Co γ-rays irradiation, and the effect of absorbed dose on crosslinking behavior was studied. Mean diameter, diameter distribution and morphology of the particles in the PBL irradiated at different doses as well as in the FVBR were characterized by laser particle analyzer and AFM. The crosslinking effect on the mechanical properties of the films, by casting from PBL at different doses correspondingly, was evaluated by mechanical and dynamic mechanical analysis (DMA) respectively. The results showed that the diameter and swelling property decreased with absorbed dose, while crosslink density and gel fraction increased. Moreover, the decrease of the tensile strength and elongation at break, the increase of the hardness in shore A and young's modulus (E), and the increase of storage modulus (E') and narrowing of loss tangent peak (Tan 8) were all accounted for the increment of crosslinking. The Charlesby-Pinner equation fits well with the PBL vulcanization in the range of absorbed doses from 0 to 200kGy. (authors)

Genomic instability induced by 60Co γ ray radiation in normal human liver cells

International Nuclear Information System (INIS)

Gen Xiaohua; Guo Xianhua; Zuo Yahui; Wang Xiaoli; Wang Zhongwen

2007-01-01

Objective: To explore the genomic instability induced by 60 Co γ rays. Methods: The cloning efficiency and micronucleus efficiency of normal human liver cell irradiated by 60 Co γ rays were detected, and the method of single cell gel electrophoresis (SCGE) was carried out to measure DNA chains damage. The fast-growing cells were divided into different dose-groups and then irradiated by 60 Co γ rays. After 40 populations doubling, the progenies were secondly irradiated with 2 Gy 60 Co γ rays. Results: The cloning efficiency decreased with the increase of doses after the initial irradiation. After the survival cells were given second irradiation, both results of SCGE and micronucleus frequency showed that the second damage was correlated with the original irradiation doses. Conclusions: 60 Co γ rays can not only induce the immediate biological effects in liver cells, but also lead to the genomic instability in the descendants that leads to an enhanced frequency of genetic changes occurring among the progeny of the original irradiated cell. The expanding effect of second event helps to study the genomic instability. (authors)

Simulation of the GCR spectrum in the Mars curiosity rover's RAD detector using MCNP6

Science.gov (United States)

Ratliff, Hunter N.; Smith, Michael B. R.; Heilbronn, Lawrence

2017-08-01

The paper presents results from MCNP6 simulations of galactic cosmic ray (GCR) propagation down through the Martian atmosphere to the surface and comparison with RAD measurements made there. This effort is part of a collaborative modeling workshop for space radiation hosted by Southwest Research Institute (SwRI). All modeling teams were tasked with simulating the galactic cosmic ray (GCR) spectrum through the Martian atmosphere and the Radiation Assessment Detector (RAD) on-board the Curiosity rover. The detector had two separate particle acceptance angles, 4π and 30 ° off zenith. All ions with Z = 1 through Z = 28 were tracked in both scenarios while some additional secondary particles were only tracked in the 4π cases. The MCNP6 4π absorbed dose rate was 307.3 ± 1.3 μGy/day while RAD measured 233 μGy/day. Using the ICRP-60 dose equivalent conversion factors built into MCNP6, the simulated 4π dose equivalent rate was found to be 473.1 ± 2.4 μSv/day while RAD reported 710 μSv/day.

Lymphoid irradiation in intractable rheumatoid arthritis. A double-blind, randomized study comparing 750-rad treatment with 2,000-rad treatment

International Nuclear Information System (INIS)

Hanly, J.G.; Hassan, J.; Moriarty, M.; Barry, C.; Molony, J.; Casey, E.; Whelan, A.; Feighery, C.; Bresnihan, B.

1986-01-01

Twenty patients with intractable rheumatoid arthritis were treated with 750-rad or 2,000-rad lymphoid irradiation in a randomized double-blind comparative study. Over a 12-month followup period, there was a significant improvement in 4 of 7 and 6 of 7 standard parameters of disease activity following treatment with 750 rads and 2,000 rads, respectively. Transient, short-term toxicity was less frequent with the lower dose. In both groups, there was a sustained peripheral blood lymphopenia, a selective depletion of T helper (Leu-3a+) lymphocytes, and reduced in vitro mitogen responses. These changes did not occur, however, in synovial fluid. These results suggest that 750-rad lymphoid irradiation is as effective as, but less toxic than, that with 2,000 rads in the management of patients with intractable rheumatoid arthritis

Studies on bone marrow damages after 60Co irradiation using uncalcified method

International Nuclear Information System (INIS)

Yamada, Mitsuaki

1976-01-01

Acute bone marrow degeneration and early regeneration after local 60 Co irradiation to rat bone marrow were studied histologically with the use of a ''Cut-all microtome''. With the use of Epon embedding, this method makes it possible to observe bone marrow in the natural state, especially to observe sinusoidal and stromal changes. After 60 Co irradiation of 500 and 1000 r to rat bone marrow, degeneration and disappearance of hematopoietic elements of the erythropoietic and granulopoietic series were noted within three days. In the hematopoietic elements of the megakaryocytic series, after 60 Co irradiation of 500 r, only mild changes were found, but after 60 Co irradiation of 1000 r, significant changes were noted. Sinusoidal and stromal reaction was also noted. Hematopoietic depression and regeneration were correlated with the disappearance and regeneration of the sinusoidal microcirculation. Against the previous reports, in the non-irradiated bone marrow, mild degeneration of the sinusoid was noted. In this study, associated with the degeneration of sinusoid -dilatation of the sinusoid and exudation-, disappearance of hematopoietic cells was noted. The etiology of the above fact is not know at present. (Evans, J.)

Experimental absorption and desorption study on a combination of 60Co, 51Cr, 137Cs, 54Mn and 22Na in the carp (Cyprinus carpio L.)

International Nuclear Information System (INIS)

Fritsh, A.F.; Baudin, J.P.

1984-03-01

The study of radionuclide behavior in water shows that about 25% of the 60 Co et 98% of the 54 Mn are found in particle form, while 96% of the 137 Cs and 87% of the 22 Na remain in solution. The soluble fraction generally remains cationic except for 60 Co, of which over one-fourth becames anionic. The uptake kinetics in the carp vary widely according to the radionuclide. The process is linear for 54 Mn, and tends to decrease in time for 137 Cs, while an equilibrium state tends to avise with 60 Co and 22 Na. The fresh weight concentration factors calculated after 65 days of experimentation were 150, 12, 3 and 120, respectively. Contaminated carp placed in non-radioactive water for 57 days lost between 45% and 65% of the 60 Co, 137 Cs and 54 Mn uptake. These elimination rates correspond to biological half-lives of 70-120 days for radioactive cobalt and cesium, and longer than 120 days for 54 Mn. The process was much more rapid with 22 Na, 95% of which was eliminated in 57 days: this corresponds to two biological half lives of 3 and 15 days. When the fish were deprived of food the process was appreciably slower, but in different proportions for each radionuclide; the effect was more significant for 137 Cs and 60 Co than for 54 Mn and 22 Na. The fecal excretion of radionuclides also diminished: smaller quantities of 60 Co and 54 Mn were eliminated under these conditions than when food was administered. Fecal excretion of 22 Na was practically nil in both cases [fr

Functional roles for Rad9 in prostate cancer

International Nuclear Information System (INIS)

Lieberman, H.B.; Broustas, C.G.

2012-01-01

The goal of this work is to understand the mechanistic relationship between high levels of Rad9 protein and prostate cancer. The study is based on several findings suggesting a role for Rad9 in this disease. Rad9 has all the hallmark features of an oncogene or tumor suppressor. It regulates genomic stability, multiple cell cycle checkpoints, apoptosis and DNA repair. In addition, it can transactivate downstream target genes via direct interaction with promoter DNA sequences. We found Rad9 protein levels were very high in prostate cancer cell lines. Furthermore, we examined 52 primary normal prostate and 339 prostate cancer specimens for Rad9 protein by immunohistochemical staining. Statistical significance for Rad9 positive staining versus cancer, and stain intensity versus Stage were tested. We get a p-value of <0.001 when comparing percentage positive by cancer Stage, or stain intensity by cancer Stage. Based on these data, we sought to define the nature of the relationship between Rad9 and prostate cancer. We demonstrate that Rad9 acts as an oncogene in prostate cancer by playing a critical role in tumor formation in a mouse xenograph model. We also show that Rad9 is important for cellular phenotypes essential for metastasis, including tumor cell migration, invasion and resistance to programmed cell death after detachment from extracellular matrix. Therefore, Rad9 is critical for several aspects of prostate tumor progression, and could serve as a novel target for anti-cancer therapy

PI-RADS v2: Current standing and future outlook.

Science.gov (United States)

Smith, Clayton P; Türkbey, Barış

2018-05-01

The Prostate Imaging-Reporting and Data System (PI-RADS) was created in 2012 to establish standardization in prostate multiparametric magnetic resonance imaging (mpMRI) acquisition, interpretation, and reporting. In hopes of improving upon some of the PI-RADS v1 shortcomings, the PI-RADS Steering Committee released PI-RADS v2 in 2015. This paper reviews the accuracy, interobserver agreement, and clinical outcomes of PI-RADS v2 and comments on the limitations of the current literature. Overall, PI-RADS v2 shows improved sensitivity and similar specificity compared to PI-RADS v1. However, concerns exist regarding interobserver agreement and the heterogeneity of the study methodology.

Ion exchange-based treatment of "6"0Co contaminated well-water for storing γ irradiation source

International Nuclear Information System (INIS)

Bi Meng; Miao Shilin; Zhang Xiaolu; Zhang Youjiu

2014-01-01

Objective: To select an efficient ion exchange resin to purify the "6"0Co contaminated well-water for storing radioactive source and to ensure the radioactivity of "6"0Co in treated well-water below 10 Bq/L. Methods: The radioactivity of "6"0Co in the water samples was measured by using the potassium cobaltinitrite coprecipitation-β counting method. The treatment efficiencies of two different ion exchange resins for the simulated "6"0Co-bearing waste water were compared to select a better one to dispose of the "6"0Co contaminated well-water. Results: The treatment efficiency of MBD-15-SC mixed ion exchange resin was about 5.8 times higher than ZGCNR50 strong-acid cation exchange resin. The radioactivity of "6"0Co in the contaminated well-water could be reduced from 4.16 × 10"5 Bq/L to 1.16 Bq/L by two-stage sorption of MBD-15-SC mixed ion exchange resin. Conclusions: Using several times of two-stage MBD-15-SC mixed ion exchange resin could effectively purify the "6"0Co contaminated well-water. The quality of the treated well-water could meet the sewage discharge standards. (authors)

Value of irradiation of neck nodes metastases. Pt. 1. Treatment of palpable nodes

International Nuclear Information System (INIS)

Bujko, K.

1993-01-01

Medical records of 222 patients with neck nodes metastases from squamous cell carcinoma of supraglottic larynx, tonsil and base of tongue were analyzed. All cases were treated with definitive irradiation. 110 patients were treated with orthovoltage technique with total doses of 5000-6000 rads, 150-10 rads per fraction; 112 patients with Co-60 with total doses 6000-7000 rads, 180-230 rads per fraction. Local-regional control was achieved in 28% of cases. Failures in the neck nodes with primary tumor controlled, were recorded in 10% of patients. Failures in a primary tumor alone were observed in 26% of patients, in primary tumor and neck nodes in 36%. Radiocurability of primary tumor and involved neck nodes was similar. In cases with primary tumor controlled, the probability of eradication of neck nodes metastases is high, even in N3 stage patients. Residual neck nodes palpable 1 to 3 months after irradiation were unfavorable prognostic factor indicated 50% risk of neck recurrence. In patients with complete regression of primary and nodal disease, failure in neck nodes was recorded in 5% of cases. The role of surgery following irradiation in patients with cervical nodes metastases is discussed. (author)

The accuracy of the SONOBREAST statistical model in comparison to BI-RADS for the prediction of malignancy in solid breast nodules detected at ultrasonography.

Science.gov (United States)

Paulinelli, Regis R; Oliveira, Luis-Fernando P; Freitas-Junior, Ruffo; Soares, Leonardo R

2016-01-01

The objective of the present study was to compare the accuracy of SONOBREAST for the prediction of malignancy in solid breast nodules detected at ultrasonography with that of the BI-RADS system and to assess the agreement between these two methods. This prospective study included 274 women and evaluated 500 breast nodules detected at ultrasonography. The probability of malignancy was calculated based on the SONOBREAST model, available at www.sonobreast.com.br, and on the BI-RADS system, with results being compared with the anatomopathology report. The lesions were considered suspect in 171 cases (34.20%), according to both SONOBREAST and BI-RADS. Agreement between the methods was perfect, as shown by a Kappa coefficient of 1 (pBI-RADS proved identical insofar as sensitivity (95.40%), specificity (78.69%), positive predictive value (48.54%), negative predictive value (98.78%) and accuracy (81.60%) are concerned. With respect to the categorical variables (BI-RADS categories 3, 4 and 5), the area under the receiver operating characteristic (ROC) curve was 94.41 for SONOBREAST (range 92.20-96.62) and 89.99 for BI-RADS (range 86.60-93.37). The accuracy of the SONOBREAST model is identical to that found with BI-RADS when the same parameters are used with respect to the cut-off point at which malignancy is suspected. Regarding the continuous probability of malignancy with BI-RADS categories 3, 4 and 5, SONOBREAST permits a more precise and individualized evaluation. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

RadVel: The Radial Velocity Modeling Toolkit

Science.gov (United States)

Fulton, Benjamin J.; Petigura, Erik A.; Blunt, Sarah; Sinukoff, Evan

2018-04-01

RadVel is an open-source Python package for modeling Keplerian orbits in radial velocity (RV) timeseries. RadVel provides a convenient framework to fit RVs using maximum a posteriori optimization and to compute robust confidence intervals by sampling the posterior probability density via Markov Chain Monte Carlo (MCMC). RadVel allows users to float or fix parameters, impose priors, and perform Bayesian model comparison. We have implemented real-time MCMC convergence tests to ensure adequate sampling of the posterior. RadVel can output a number of publication-quality plots and tables. Users may interface with RadVel through a convenient command-line interface or directly from Python. The code is object-oriented and thus naturally extensible. We encourage contributions from the community. Documentation is available at http://radvel.readthedocs.io.

Calculation of uncertainties in the protocol of dosimetry for Co 60 beams in Radiotherapy; Calculo de incertidumbres en el protocolo de dosimetria para haces de Co 60 en Radioterapia

Energy Technology Data Exchange (ETDEWEB)

Velazquez M, S.; Carrera M, F.; Sanchez S, J. [Hospital Juan Ramon Jimenez, Ronda Norte s/n 21005 Huelva (Spain)

1998-12-31

The objective in this work is to show how the uncertainty is possible to know in the determination of the absorbed dose in Co 60 photon beams and to establish in a rational form, tolerance levels for this. It is took as base the spanish protocol of dosimetry in Radiotherapy. We have been centered in a Co 60 beam. We utilized the statistical theory of little samples. We allowed to suggest a new approach about the treatment of the tolerance levels and the uncertainty of the measurement. After two years of experience in the practical hospitable application we have gotten to put around 1 % uncertainty in the absolute dosimetry of the Co 60 beam. The presented protocol allows to execute the accuracy requirements in the determination of absorbed doses. (Author)

Scanning electron microscopy of mouse intestinal mucosa after cobalt 60 and D-T neutron irradiation

International Nuclear Information System (INIS)

Hamlet, R.; Carr, K.R.; Toner, P.G.; Nias, A.H.W.

1976-01-01

The stem-cell population of the intestinal crypt is an important model system in experimental radiobiology. Standardized techniques have been developed to allow quantitation of the response of crypt cells to radiation injury following doses of 0 to 2 krad of D-T neutrons or 60 Co γ rays. These techniques rely on the identification of regenerating crypt cells three-and-a-half days after irradiation. The results were expressed as the number of regenerating crypts per circumference of small intestine, as determined by conventional histological examination; the more profound the injury, the smaller the the crypt count. The practical relevance of crypt-counting techniques to clinical radiotherapy is limited by their relative insensitivity; the dose levels commonly used in fractionated radiotherapy produced no detectable response. Scanning electron microscopy of the mucosal surface provided a more sensitive measure of radiation injury. The earliest detectable changes occurred at the level of 300 rad of γ radiation, well below the threshold of the crypt-counting technique. At around 1,000 rad, where the first drop in crypt counts occurred, there were well-marked morphological changes which became more severe with increasing dose levels. Some differences have been observed between the morphological effects of γ and neutron irradiation at points of radiobiological equivalence in terms of crypt counts (using RBE value of about 2). The changes observed may reflect more than the disruption of epithelial cell kinetics. Mucosal morphology is the total expression of many different biological parameters of which the regenerative ability of the crypt cells is only one. The surface microanatomy of the gut may be the most sensitive indicator of radiation injury which is conveniently available for study. (author)

Scanning electron microscopy of mouse intestinal mucosa after cobalt 60 and D-T neutron irradiation

Energy Technology Data Exchange (ETDEWEB)

Hamlet, R [Belvidere Hospital, Glasgow (UK). Institute of Radiotherapeutics and Oncology; Carr, K R; Toner, P G; Nias, A H.W.

1976-07-01

The stem-cell population of the intestinal crypt is an important model system in experimental radiobiology. Standardized techniques have been developed to allow quantitation of the response of crypt cells to radiation injury following doses of 0 to 2 krad of D-T neutrons or /sup 60/Co ..gamma.. rays. These techniques rely on the identification of regenerating crypt cells three-and-a-half days after irradiation. The results were expressed as the number of regenerating crypts per circumference of small intestine, as determined by conventional histological examination; the more profound the injury, the smaller the the crypt count. The practical relevance of crypt-counting techniques to clinical radiotherapy is limited by their relative insensitivity; the dose levels commonly used in fractionated radiotherapy produced no detectable response. Scanning electron microscopy of the mucosal surface provided a more sensitive measure of radiation injury. The earliest detectable changes occurred at the level of 300 rad of ..gamma.. radiation, well below the threshold of the crypt-counting technique. At around 1,000 rad, where the first drop in crypt counts occurred, there were well-marked morphological changes which became more severe with increasing dose levels. Some differences have been observed between the morphological effects of ..gamma.. and neutron irradiation at points of radiobiological equivalence in terms ofCrypt counts (using RBE value of about 2). The changes observed may reflect more than the disruption of epithelial cell kinetics. Mucosal morphology is the total expression of many different biological parameters of which the regenerative ability of the crypt cells is only one. The surface microanatomy of the gut may be the most sensitive indicator of radiation injury which is conveniently available for study.

Co-60 and Ca-45 autoradiography in cerebral ischemia in the rat

NARCIS (Netherlands)

Stevens, H; Krop-van Gastel, W; Korf, J

1998-01-01

Radioisotopes of divalent Co (Co-57 in Single photon emission tomography (SPECT)and Co-55 in positron emission tomography (PET) have clinically been applied to visualize Ca related brain damage. The cerebral uptake of Ca-45 and Co-60 in a unilateral stroke model in the rat was compared; 100 mu Ci

The effect of environmental factors on the uptake of 60Co by Paecilomyces catenlannulatus

International Nuclear Information System (INIS)

Fengbo Li; Xiaoyu Li; Lejin Fang; Zhimo Gao

2014-01-01

Paecilomyces catenlannulatus (P. catenlannulatus), a kind of important pathogenic fungi of forest pests, can be regarded as an excellent material to retard the fate and transport of radionuclides. The effect of environmental factors (i.e., pH, ionic strength, temperature and solution concentration) on the uptake of 60 Co by P. catenlannulatus was investigated by batch technique. The results showed that the uptake of 60 Co by P. catenlannulatus was independent of pH at pH 60 Co was observed with increasing pH from 5.0 to 8.0, then remained the high-level uptake at pH > 8.0 due to occurrence of precipitates. It is found that 60 Co uptake significantly decreased with increasing ionic strength at low pH, whereas little change was observed at high pH. The pH dependence adsorption indicates that the interaction mechanism between 60 Co and P. catenlannulatus is ion exchange at low pH and surface complexation at high pH conditions, respectively. Compared to Freundlich model, the adsorption isotherms can be fitted by Langmuir model very well. The thermodynamic data calculated from the temperature adsorption isotherms indicated that the uptake process of 60 Co by P. catenlannulatus was an endothermic and spontaneous process. This paper focused on potential application of P. catenlannulatus as suitable bio-materials for the preconcentration and removal of radionuclides from aqueous solutions in environmental pollution management. (author)

Functional analysis of the RAD50/MRE11 protein complex through targeted disruption of the murine RAD50 genomic locus: implications for DNA double strand break repair. An astro research fellowship presentation

International Nuclear Information System (INIS)

Yao, Michelle S.; Bladl, Anthony R.; Petrini, John H.J.

1997-01-01

mutation in S. cerevisiae) or an inducible deletion of exons 1 and 2, in conjunction with the positive- and negative- selection markers neo and tk.. In one construct, the mutation was rendered inducible by cre recombinase co-expression through the placement of loxP sites on either side of the desired deletion. Additional cDNA expression vectors containing wild-type or non-null mutant muRAD50 cDNAs have also been constructed. Murine ES cells were transfected by electroporation, followed by G418 selection. Resultant colonies were isolated, expanded, and screened for recombinational integration at the RAD50 locus by Southern blotting. Expression from the mutant allele was confirmed by RT-PCR. Induction of the null mutation was effected by transient expression of cre recombinase, with negative selection by gancyclovir for detection of induced mutants. Mouse blastocysts were injected with transfected cells, with resultant chimeric animals screened for germline transmission of the mutant allele. Results/Conclusions: Murine Rad50 and Mre11 are co-immunoprecipitable from whole cell lysates, implying conservation of the protein complex seen in S. cerevisiae. A 153 kD protein corresponding to muRad50 was detected by anti-Rad50 antiserum in all tissue types examined, but was most prominent in testis, thymus, and large bowel. In addition, two smaller bands of approximately 68 and 72 kD were detected in brain tissue; a 96 kD band was detected in heart and skeletal muscle. Whether these bands represent tissue-specific muRad50 isoforms or other cross-reactive species remains to be determined. Several ES cell lines have been established which include null or inducible-null mutations at one muRAD50 locus. Nullizygous lines, as well as lines carrying non-null murad50 mutations are being made. Phenotypic analyses of null and non-null mutants, to include IR sensitivity by clonogenic cell survival assay, DNA dsb repair capacity by single-cell gel electrophoresis, and recombinational phenotype

Long Term RadNet Quality Data

Data.gov (United States)

U.S. Environmental Protection Agency — This RadNet Quality Data Asset includes all data since initiation and when ERAMS was expanded to become RadNet, name changed to reflect new mission. This includes...

SU-E-T-380: Evaluation of BEBIG HDR 60Co System for AccuBoost Therapy

Energy Technology Data Exchange (ETDEWEB)

Zehtabian, M; Sina, S [Shiraz University, Shiraz, Fars (Iran, Islamic Republic of); Rivard, M [Tufts University School of Medicine, Boston, MA (United States); Meigooni, A Soleimani [Comprehensive Cancer Center of Nevada, Las Vegas, Nevada (United States)

2015-06-15

Purpose: In this project, the possibility of utilizing the BEBIG 60Co HDR system for AccuBoostTM treatment has been evaluated. Methods: Dose distributions in various breast sizes have been calculated for both Co-60 and Ir-192 sources using the MCNP5 code. These calculations were performed in breast tissues with thicknesses of 4cm, 6cm, and 8cm. The initial calculations were performed with the same applicator dimensions as the existing applicators used with the HDR Ir-192 system. The activity of the Co-60 source was selected such that the dose at the breast center was the same as the values from 192Ir. Then, the applicator thicknesses were increased to twice of those used with HDR Ir-192 system, for reducing skin and chest doses by Co-60 system. Dose to breast skin and chest wall were compared for both applicators types, with and without inclusion of a focusing cone at the applicator center. Results: The results showed that loading HDR Co-60 source inside the thin applicators impose higher doses to breast skin and chest wall compared to the 192Ir source. The area of the chest wall covered by 10Gy when treated by Co-60 with the thin and thick applicators, or treated by Ir-192 with thin applicator are 79cm2, 39cm2, and 3.8cm2, respectively. These values are reduced to 34cm2, 0cm2, and 0cm2 by using the focusing cone. It is worth noting that the breast skin areas covered by the 60Gy isodose line are 9.9cm2 and 7.8cm2 for Co-60 with the thin and thick applicators, respectively, while it is 20cm2 for Ir-192 when no focusing cone is present. These values are 0cm2, 0cm2, and 11cm2 in the presence of the focusing cone. Conclusion: The results indicate that using Co-60 with the thicker applicators is beneficial because of the higher half-life of Co-60, and the reduced maximum skin dose when compared with Ir-192.

Therapeutic results in ovarian cancer after replacement of conventional radiotherapy by Co-60 irradiation

International Nuclear Information System (INIS)

Kucera, H.; Szalay, St.; Weghaupt, K.; Heckenthaler, W.; Vienna Univ.

1981-01-01

The use of Co-60 screen and pendular irradiation instead of conventional radiotherapy has brought about an improvement in the 5-year survival rate in patients with more advanced stages of ovarian cancer. Although the general side effects of Co-60 irradiation are considered to be more unpleasant than those of X-ray and radium therapy, severe, reversible or irreversible damage to the urogenital tract and intestinal organs was diminished by accurate planning of Co-60 therapy, so that these complications occurred less frequently than with conventional radiotherapy. (author)

Development of technology for the large-scale preparation of 60Co polymer film source

International Nuclear Information System (INIS)

Udhayakumar, J.; Pardeshi, G.S.; Gandhi, Shymala S.; Chakravarty, Rubel; Kumar, Manoj; Dash, Ashutosh; Venkatesh, Meera

2008-01-01

60 Co sources (∼37 kBq) in the form of a thin film are widely used in position identification of perforation in offshore oil-well explorations. This paper describes the large-scale preparation of such sources using a radioactive polymer containing 60 Co. 60 Co was extracted into chloroform containing 8-hydroxyquinoline. The chloroform layer was mixed with polymethyl methacrylate (PMMA) polymer. A large film was prepared using the polymer solution containing the complex. The polymer film was then cut into circular sources, mounted on a source holder and supplied to various users

RadGenomics project

Energy Technology Data Exchange (ETDEWEB)

Iwakawa, Mayumi; Imai, Takashi; Harada, Yoshinobu [National Inst. of Radiological Sciences, Chiba (Japan). Frontier Research Center] [and others

2002-06-01

Human health is determined by a complex interplay of factors, predominantly between genetic susceptibility, environmental conditions and aging. The ultimate aim of the RadGenomics (Radiation Genomics) project is to understand the implications of heterogeneity in responses to ionizing radiation arising from genetic variation between individuals in the human population. The rapid progression of the human genome sequencing and the recent development of new technologies in molecular genetics are providing us with new opportunities to understand the genetic basis of individual differences in susceptibility to natural and/or artificial environmental factors, including radiation exposure. The RadGenomics project will inevitably lead to improved protocols for personalized radiotherapy and reductions in the potential side effects of such treatment. The project will contribute to future research into the molecular mechanisms of radiation sensitivity in humans and will stimulate the development of new high-throughput technologies for a broader application of biological and medical sciences. The staff members are specialists in a variety of fields, including genome science, radiation biology, medical science, molecular biology, and informatics, and have joined the RadGenomics project from various universities, companies, and research institutes. The project started in April 2001. (author)

RadGenomics project

International Nuclear Information System (INIS)

Iwakawa, Mayumi; Imai, Takashi; Harada, Yoshinobu

2002-01-01

Human health is determined by a complex interplay of factors, predominantly between genetic susceptibility, environmental conditions and aging. The ultimate aim of the RadGenomics (Radiation Genomics) project is to understand the implications of heterogeneity in responses to ionizing radiation arising from genetic variation between individuals in the human population. The rapid progression of the human genome sequencing and the recent development of new technologies in molecular genetics are providing us with new opportunities to understand the genetic basis of individual differences in susceptibility to natural and/or artificial environmental factors, including radiation exposure. The RadGenomics project will inevitably lead to improved protocols for personalized radiotherapy and reductions in the potential side effects of such treatment. The project will contribute to future research into the molecular mechanisms of radiation sensitivity in humans and will stimulate the development of new high-throughput technologies for a broader application of biological and medical sciences. The staff members are specialists in a variety of fields, including genome science, radiation biology, medical science, molecular biology, and informatics, and have joined the RadGenomics project from various universities, companies, and research institutes. The project started in April 2001. (author)

The effect of fractional CO2 laser irradiation on remineralization of enamel white spot lesions.

Science.gov (United States)

Poosti, Maryam; Ahrari, Farzaneh; Moosavi, Horieh; Najjaran, Hoda

2014-07-01

This study investigated the combined effect of fractional CO(2) laser irradiation and fluoride on treatment of enamel caries. Sixty intact premolars were randomly assigned into four groups and then stored in a demineralizing solution to induce white spot lesions. Tooth color was determined at baseline (T1) and after demineralization (T2). Afterwards, the teeth in group 1 remained untreated (control), while group 2 was exposed to an acidulated phosphate fluoride (APF) gel for 4 min. In groups 3 and 4, a fractional CO(2) laser was applied (10 mJ, 200 Hz, 10 s) either before (group 3) or through (group 4) the APF gel. The teeth were then immersed in artificial saliva for 90 days while subjected to daily fluoride mouthrinse and weekly brushing. Color examinations were repeated after topical fluoride application (T3) and 90 days later (T4). Finally, the teeth were sectioned, and microhardness was measured at the enamel surface and at 30 and 60 μ from the surface. In both lased groups, the color change between T1 and T4 stages (∆E(T1-T4)) was significantly lower than those of the other groups (p Laser irradiation followed by fluoride application (group 3) caused a significant increase in surface microhardness compared to APF alone and control groups (p laser before fluoride therapy is suggested for recovering the color and rehardening of demineralized enamel.

Carbon-14 based determination of the biogenic fraction of industrial CO(2) emissions - application and validation.

Science.gov (United States)

Palstra, S W L; Meijer, H A J

2010-05-01

The (14)C method is a very reliable and sensitive method for industrial plants, emission authorities and emission inventories to verify data estimations of biogenic fractions of CO(2) emissions. The applicability of the method is shown for flue gas CO(2) samples that have been sampled in 1-h intervals at a coal- and wood-fired power plant and a waste incineration plant. Biogenic flue gas CO(2) fractions of 5-10% and 48-50% have been measured at the power plant and the waste incineration plant, respectively. The reliability of the method has been proven by comparison of the power plant results with those based on carbon mass input and output data of the power plant. At industrial plants with relatively low biogenic CO(2) fraction (<10%) the results need to be corrected for sampled (14)CO(2) from atmospheric air. Copyright 2009 Elsevier Ltd. All rights reserved.

Sorption of Cs-137 and Co-60 in Natural Zeolites; Sorcion de Cs-137 y Co-60 en zeolitas naturales

Energy Technology Data Exchange (ETDEWEB)

Chales Suarez, G; Moreno Alvarez, D; Coutin Correa, D [Agencia de Energia Nuclear, La Habana (Cuba)

1996-07-01

The sorption of Cs-137 and Co-60 in natural zeolites under different conditions was studied. The behaviour of samples of mineral and rock from different deposit of the country was obtained and the decontamination of radioactive waters containing both radionuclides was performed; as part of the research to determine its application in the treatment of radioactive wastes in the country.

Comparison of atmospheric CO2 mole fractions and source-sink characteristics at four WMO/GAW stations in China

Science.gov (United States)

Cheng, Siyang; Zhou, Lingxi; Tans, Pieter P.; An, Xingqin; Liu, Yunsong

2018-05-01

As CO2 is a primary driving factor of climate change, the mole fraction and source-sink characteristics of atmospheric CO2 over China are constantly inferred from multi-source and multi-site data. In this paper, we compared ground-based CO2 measurements with satellite retrievals and investigated the source-sink regional representativeness at China's four WMO/GAW stations. The results indicate that, firstly, atmospheric CO2 mole fractions from ground-based sampling measurement and Greenhouse Gases Observing Satellite (GOSAT) products reveal similar seasonal variation. The seasonal amplitude of the column-averaged CO2 mole fractions is smaller than that of the ground-based CO2 at all stations. The extrema of the seasonal cycle of ground-based and column CO2 mole fractions are basically synchronous except a slight phase delay at Lin'an (LAN) station. For the two-year average, the column CO2 is lower than ground-based CO2, and both of them reveal the lowest CO2 mole fraction at Waliguan (WLG) station. The lowest (∼4 ppm) and largest (∼8 ppm) differences between the column and ground-based CO2 appear at WLG and Longfengshan (LFS) stations, respectively. The CO2 mole fraction and its difference between GOSAT and ground-based measurement are smaller in summer than in winter. The differences of summer column CO2 among these stations are also much smaller than their ground-based counterparts. In winter, the maximum of ground-based CO2 mole fractions and the greatest difference between the two (ground-based and column) datasets appear at the LFS station. Secondly, the representative areas of the monthly CO2 background mole fractions at each station were found by employing footprints and emissions. Smaller representative areas appeared at Shangdianzi (SDZ) and LFS, whereas larger ones were seen at WLG and LAN. The representative areas in summer are larger than those in winter at WLG and SDZ, but the situation is opposite at LAN and LFS. The representative areas for the

Structured reporting platform improves CAD-RADS assessment.

Science.gov (United States)

Szilveszter, Bálint; Kolossváry, Márton; Karády, Júlia; Jermendy, Ádám L; Károlyi, Mihály; Panajotu, Alexisz; Bagyura, Zsolt; Vecsey-Nagy, Milán; Cury, Ricardo C; Leipsic, Jonathon A; Merkely, Béla; Maurovich-Horvat, Pál

2017-11-01

Structured reporting in cardiac imaging is strongly encouraged to improve quality through consistency. The Coronary Artery Disease - Reporting and Data System (CAD-RADS) was recently introduced to facilitate interdisciplinary communication of coronary CT angiography (CTA) results. We aimed to assess the agreement between manual and automated CAD-RADS classification using a structured reporting platform. Five readers prospectively interpreted 500 coronary CT angiographies using a structured reporting platform that automatically calculates the CAD-RADS score based on stenosis and plaque parameters manually entered by the reader. In addition, all readers manually assessed CAD-RADS blinded to the automatically derived results, which was used as the reference standard. We evaluated factors influencing reader performance including CAD-RADS training, clinical load, time of the day and level of expertise. Total agreement between manual and automated classification was 80.2%. Agreement in stenosis categories was 86.7%, whereas the agreement in modifiers was 95.8% for "N", 96.8% for "S", 95.6% for "V" and 99.4% for "G". Agreement for V improved after CAD-RADS training (p = 0.047). Time of the day and clinical load did not influence reader performance (p > 0.05 both). Less experienced readers had a higher total agreement as compared to more experienced readers (87.0% vs 78.0%, respectively; p = 0.011). Even though automated CAD-RADS classification uses data filled in by the readers, it outperforms manual classification by preventing human errors. Structured reporting platforms with automated calculation of the CAD-RADS score might improve data quality and support standardization of clinical decision making. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

The C-terminal region of Rad52 is essential for Rad52 nuclear and nucleolar localization, and accumulation at DNA damage sites immediately after irradiation

Energy Technology Data Exchange (ETDEWEB)

Koike, Manabu, E-mail: m_koike@nirs.go.jp [DNA Repair Gene Res., National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Yutoku, Yasutomo [DNA Repair Gene Res., National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Graduate School of Science, Chiba University, Yayoicho, Inage-ku, Chiba 263-8522 (Japan); Koike, Aki [DNA Repair Gene Res., National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan)

2013-05-31

Highlights: •Rad52 might play a key role in the repair of DSB immediately after irradiation. •EYFP-Rad52 accumulates rapidly at DSB sites and colocalizes with Ku80. •Accumulation of Rad52 at DSB sites is independent of the core NHEJ factors. •Localization and recruitment of Rad52 to DSB sites are dependent on the Rad52 CTR. •Basic amino acids in Rad52 CTR are highly conserved among vertebrate species. -- Abstract: Rad52 plays essential roles in homologous recombination (HR) and repair of DNA double-strand breaks (DSBs) in Saccharomyces cerevisiae. However, in vertebrates, knockouts of the Rad52 gene show no hypersensitivity to agents that induce DSBs. Rad52 localizes in the nucleus and forms foci at a late stage following irradiation. Ku70 and Ku80, which play an essential role in nonhomologous DNA-end-joining (NHEJ), are essential for the accumulation of other core NHEJ factors, e.g., XRCC4, and a HR-related factor, e.g., BRCA1. Here, we show that the subcellular localization of EYFP-Rad52(1–418) changes dynamically during the cell cycle. In addition, EYFP-Rad52(1–418) accumulates rapidly at microirradiated sites and colocalizes with the DSB sensor protein Ku80. Moreover, the accumulation of EYFP-Rad52(1–418) at DSB sites is independent of the core NHEJ factors, i.e., Ku80 and XRCC4. Furthermore, we observed that EYFP-Rad52(1–418) localizes in nucleoli in CHO-K1 cells and XRCC4-deficient cells, but not in Ku80-deficient cells. We also found that Rad52 nuclear localization, nucleolar localization, and accumulation at DSB sites are dependent on eight amino acids (411–418) at the end of the C-terminal region of Rad52 (Rad52 CTR). Furthermore, basic amino acids on Rad52 CTR are highly conserved among mammalian, avian, and fish homologues, suggesting that Rad52 CTR is important for the regulation and function of Rad52 in vertebrates. These findings also suggest that the mechanism underlying the regulation of subcellular localization of Rad52 is

Stable carbon isotope fractionation of organic cyst-forming dinoflagellates: Evaluating the potential for a CO2 proxy

Science.gov (United States)

Hoins, Mirja; Van de Waal, Dedmer B.; Eberlein, Tim; Reichart, Gert-Jan; Rost, Björn; Sluijs, Appy

2015-07-01

Over the past decades, significant progress has been made regarding the quantification and mechanistic understanding of stable carbon isotope fractionation (13C fractionation) in photosynthetic unicellular organisms in response to changes in the partial pressure of atmospheric CO2 (pCO2). However, hardly any data is available for organic cyst-forming dinoflagellates while this is an ecologically important group with a unique fossil record. We performed dilute batch experiments with four harmful dinoflagellate species known for their ability to form organic cysts: Alexandrium tamarense, Scrippsiella trochoidea, Gonyaulax spinifera and Protoceratium reticulatum. Cells were grown at a range of dissolved CO2 concentrations characterizing past, modern and projected future values (∼5-50 μmol L-1), representing atmospheric pCO2 of 180, 380, 800 and 1200 μatm. In all tested species, 13C fractionation depends on CO2 with a slope of up to 0.17‰ (μmol L)-1. Even more consistent correlations were found between 13C fractionation and the combined effects of particulate organic carbon quota (POC quota; pg C cell-1) and CO2. Carbon isotope fractionation as well as its response to CO2 is species-specific. These results may be interpreted as a first step towards a proxy for past pCO2 based on carbon isotope ratios of fossil organic dinoflagellate cysts. However, additional culture experiments focusing on environmental variables other than pCO2, physiological underpinning of the recorded response, testing for possible offsets in 13C values between cells and cysts, as well as field calibration studies are required to establish a reliable proxy.

Vegetation height and cover fraction between 60° S and 60° N from ICESat GLAS data

Directory of Open Access Journals (Sweden)

S. O. Los

2012-03-01

Full Text Available We present new coarse resolution (0.5° × 0.5° vegetation height and vegetation-cover fraction data sets between 60° S and 60° N for use in climate models and ecological models. The data sets are derived from 2003–2009 measurements collected by the Geoscience Laser Altimeter System (GLAS on the Ice, Cloud and land Elevation Satellite (ICESat, the only LiDAR instrument that provides close to global coverage. Initial vegetation height is calculated from GLAS data using a development of the model of Rosette et al. (2008 with with further calibration on desert sites. Filters are developed to identify and eliminate spurious observations in the GLAS data, e.g. data that are affected by clouds, atmosphere and terrain and as such result in erroneous estimates of vegetation height or vegetation cover. Filtered GLAS vegetation height estimates are aggregated in histograms from 0 to 70 m in 0.5 m intervals for each 0.5° × 0.5°. The GLAS vegetation height product is evaluated in four ways. Firstly, the Vegetation height data and data filters are evaluated using aircraft LiDAR measurements of the same for ten sites in the Americas, Europe, and Australia. Application of filters to the GLAS vegetation height estimates increases the correlation with aircraft data from r = 0.33 to r = 0.78, decreases the root-mean-square error by a factor 3 to about 6 m (RMSE or 4.5 m (68% error distribution and decreases the bias from 5.7 m to −1.3 m. Secondly, the global aggregated GLAS vegetation height product is tested for sensitivity towards the choice of data quality filters; areas with frequent cloud cover and areas with steep terrain are the most sensitive to the choice of thresholds for the filters. The changes in height estimates by applying different filters are, for the main part, smaller than the overall uncertainty of 4.5–6 m established from the site measurements. Thirdly, the GLAS global vegetation height product is compared with a

Detection and thermoluminescence of coriander (Coriandrum sativum L.) irradiated with 60Co

International Nuclear Information System (INIS)

Ruiz G, B.; Cruz Z, E.; Barboza F, M.

2009-10-01

The fresh and dried coriander (Coriandrum sativum L.) is a spice of high commercial value as food for consumption in Mexico. Their hygienic quality is often poor due to some factors: contaminants present in irrigation water and the cultivation atmosphere, harvesting and post harvest handling, mainly. The process by radiation is an alternative to achieve the sterilization to adequate dose for the hygienic quality for its consumption. However, irradiation also involves food detection exposed to radiation. This paper presents detected results on the dried coriander that was obtained from fresh samples and thermoluminescent properties such as glow curves structure from low doses (0.5 Gy) to high (15 kGy), the dose response, thermoluminescent signal decay, in order to determine the loss of stability during the storage of the poly mineral fraction. We obtained the inorganic fraction separation of the organic part of particle sizes of 10 μm by the Zimmerman method. The samples were exposed at two dose ranges; 0.5-400 Gy and 0.5-15 kGy of gamma radiation with 60 Co. The limit of thermoluminescent detection of the irradiated coriander samples was from 1 Gy. The glow curves were at a broad band of 35-400 C, with a maximum thermoluminescence around 182-196 C, and run at 164 C for high doses of 15 kGy. The range of linear response to dose was 4-25 Gy, whereas higher doses than the kGy order the response increase with the dose. The thermoluminescent properties of the coriander poly mineral fraction, show it can be used to identify irradiated food at gamma doses relatively low and even in doses of commercial interest due to the high stability of thermoluminescent signals. (Author)

Pathologic effects of fractionated fast neutrons or photons on canine liver

International Nuclear Information System (INIS)

Zook, B.C.; Bradley, E.W.; Casarett, G.W.; Hitzelberg, R.A.; Rogers, C.C.

1981-01-01

Thirty-nine adult male purebred beagles received either fast neutron or photon irradiation to the right thorax to determine the effects on pulmonary tissue. The right half of the liver was included in the field of radiation. Twenty-four dogs (six/group) received fast neutrons with a mean energy of 15 MeV to total doses of 1000, 1500, 2250, or 3375 rads in four fractions per week for 6 weeks. Fifteen dogs received 3000, 4500, or 6750 total rads of photons (five dogs/group) in an identical fractionation pattern. All neutron-irradiated dogs receiving 3375 and 2250 rads and one receiving 1500 rads developed clinical signs, hepatic enzyme, and bilirubin elevations, and the dogs died or were euthanized in extremis on postirradiation day 47-291. Signs of liver injury, other than enzyme changes, have not developed to date (1200 to 1300 days) in the remaining dogs, except in one 6750-rad photon dog that died of hepatic failure on postirradiation day 708. At necropsy, the irradiated right lobes of the liver were atrophic and the nonirradiated left lobes underwent compensatory hypertrophy. Hepatic arterioles and bile ducts were injured in every dog, but no obstructive lesions were observed in hepatic veins. Portal fibroplasia, bile retention, and proliferation of bile ductules was common; the latter two changes also occurred in the nonirradiated lobes. No qualitative differences were observed between hepatic lesions in neutron-versus photon-irradiated dogs. The relative biological effectiveness of fast neutrons for liver damage appears to be no less than 4.5

Pathologic effects of fractionated fast neutrons or photons on canine liver

International Nuclear Information System (INIS)

Zook, B.C.; Bradley, E.W.; Casarett, G.W.; Hitzelberg, R.A.; Rogers, C.C.

1981-01-01

Thirty-nine adult male purebred beagles received either fast neutron or photon irradiation to the right thorax to determine the effects on pulmonary tissue. The right half of the liver was included in the field of radiation. Twenty-four dogs (six/group) received fast neutrons with a mean energy of 15 MeV to total doses of 1000, 1500, 2250, or 3375 rads in four fractions per week for 6 weeks. Fifteen dogs received 3000, 4500, or 6750 total rads of photons (five dogs/group) in an identical fractionation pattern. All neutron-irradiated dogs receiving 3375 and 2250 rads and one receiving 1500 rads developed clinical signs, hepatic enzyme, and bilirubin elevations, and the dogs died or were euthanized in extremis on postirradiation day 47-291. Signs of liver injury, other than enzyme changes, have not developed to date (1200-1300 days) in the remaining dogs, except in one 6750-rad photon dog that died of hepatic failure on postirradiation day 708. At necropsy, the irradiated right lobes of the liver were atrophic and the nonirradiated left lobes underwent compensatory hypertrophy. Hepatic arterioles and bile ducts were injured in every dog, but no obstructive lesions were observed in hepatic veins. Portal fibroplasia, bile retention, and proliferation of bile ductules was common; the latter two changes also occurred in the nonirradiated lobes. No qualitative differences were observed between hepatic lesions in neutron- versus photon-irradiated dogs. The relative biological effectiveness of fast neutrons for liver damage appears to be no less than 4.5

Histological variations in liver of freshwater fish Oreochromis mossambicus exposed to 60Co gamma irradiation

International Nuclear Information System (INIS)

Sadiq Bukhari, A.; Syed Mohamed, H.E.; Broos, K.V.; Stalin, A.; Singhal, R.K.; Venubabu, P.

2012-01-01

The irradiation effect of 60 Co at the three dose level of 3 mGy, 30 mGy and 300 mGy on the histology of liver of the freshwater fish Oreochromis mossambicus was investigated. The liver of O. mossambicus was dissected out and processed for light microscopy studies. 60 Co exposed O. mossambicus were found to result in several alterations in the histoarchitecture of liver. The alterations included mild congestion of blood vessels, structural alteration, cellular swelling, vacuolation and necrotic liver cells, indicating a definite response to 60 Co irradiation. The results suggest that the liver of O. mossambicus exposed to 60 Co were structurally altered with increasing dose levels. It is to record that alteration in the liver does not affect the physiology, behaviour or lethality of the individuals. Self regulating mechanisms would have influenced the liver to remain sustained. To confirm the same further studies in the direction by increasing dose level is required. - Highlights: ► Fish Oreochromis mossambicus irradiated to the dose of 3 mGy, 30 mGy and 300 mGy. ► Histoarchitecture of liver altered with increasing dose levels of 60 Co. ► Alteration in the liver does not affect the physiology, behaviour or lethality. ► Self regulating mechanisms might have prevented from Lethality. ► HSI index value for exposed group reported ( 60 Co.

RAD18 mediates resistance to ionizing radiation in human glioma cells

International Nuclear Information System (INIS)

Xie, Chen; Wang, Hongwei; Cheng, Hongbin; Li, Jianhua; Wang, Zhi; Yue, Wu

2014-01-01

Highlights: • RAD18 is an important mediator of the IR-induced resistance in glioma cell lines. • RAD18 overexpression confers resistance to IR-mediated apoptosis. • The elevated expression of RAD18 is associated with recurrent GBM who underwent IR therapy. - Abstract: Radioresistance remains a major challenge in the treatment of glioblastoma multiforme (GBM). RAD18 a central regulator of translesion DNA synthesis (TLS), has been shown to play an important role in regulating genomic stability and DNA damage response. In the present study, we investigate the relationship between RAD18 and resistance to ionizing radiation (IR) and examined the expression levels of RAD18 in primary and recurrent GBM specimens. Our results showed that RAD18 is an important mediator of the IR-induced resistance in GBM. The expression level of RAD18 in glioma cells correlates with their resistance to IR. Ectopic expression of RAD18 in RAD18-low A172 glioma cells confers significant resistance to IR treatment. Conversely, depletion of endogenous RAD18 in RAD18-high glioma cells sensitized these cells to IR treatment. Moreover, RAD18 overexpression confers resistance to IR-mediated apoptosis in RAD18-low A172 glioma cells, whereas cells deficient in RAD18 exhibit increased apoptosis induced by IR. Furthermore, knockdown of RAD18 in RAD18-high glioma cells disrupts HR-mediated repair, resulting in increased accumulation of DSB. In addition, clinical data indicated that RAD18 was significantly higher in recurrent GBM samples that were exposed to IR compared with the corresponding primary GBM samples. Collectively, our findings reveal that RAD18 may serve as a key mediator of the IR response and may function as a potential target for circumventing IR resistance in human GBM

60Co γ-irradiation enhances expression of GAP-43 mRNA in rat brain

International Nuclear Information System (INIS)

Su Bingyin; Cai Wenqin; Zhang Chenggang

2001-01-01

Objective: To study the relationship between the expression of GAP-43 mRNA and nerve regeneration in rat brain after 60 Co γ-irradiation. Methods: Wistar rats were subjected to whole-body irradiation with 8 Gy 60 Co γ-rays. The expression of GAP-43 was detected by in situ hybridization histochemistry using Dig-cRNA probe. Results: It was found that the expression of GAP-43 mRNA increased in the cerebral cortex, caudate, putamen, globus pallidum, thalamus and hypothalamus one week after 8 Gy 60 Co γ-irradiation. The peak of GAP-43 mRNA expression was observed in the fourth week and then began to decrease but still remained at a higher than normal level. However, it decreased to a low level after 7 weeks. Conclusion: Enhanced expression of GAP-43 mRNA after 60 Co γ-irradiation in rat brain is associated with nerve regeneration and reconstruction of synapse

Selective extraction of cobalt 60 and radium on CSA's SIMTM system

International Nuclear Information System (INIS)

Denton, M.S.; Higgins, I.R.

1988-01-01

CSA, has developed and promoted a new ground/well water treatment media and support system for hydrogen sulfide, iron, and manganese called The SIM System. This media was also found to have a selective affinity for arsenic, selenium, antimony, bismuth and lead. All heavy metals have not been checked, but of special rad-waste interest is Co-60 and Ra-226. Barium has been used as a stand-in for Ra in the lab, but both Co and Ba have exhibited very high affinities from Oak Ridge waters. A very attractive feature is that the adsorbed metals may be eluted with a minimum of acid, unlike ion exchangers that regenerate with difficulty or zeolites which dissolve in acids. This opens up the new dimension of extraction/concentration of these contaminants. Ordinary water softening ion exchange resin is excellent for extraction of Ra from drinking water, but, as mentioned, regenerates with great difficulty. The SIM media may be used for pre-treatment with the acid regenerant reloaded on ordinary resin for a very high concentration of Ra, or Co, for final disposal. The very stable SIM media may also be disposed of directly. Strontium (Sr-90) affinity isn't as great as for barium, but is greater than calcium. The separation factor of SIM for Sr/Ca may well be better than the value of two (2) observed for ordinary cation resin. Further studies are being made to demonstrate the full potential of this selective media for certain rad-wastes

Study on the production mechanism of Co-60 in the primary loop of HTR-10

International Nuclear Information System (INIS)

Wang Shouang; Xie Feng; Li Hong; Cao Jianzhu; Li Fu; Wei Liqiang

2015-01-01

Co-60 is an activated metallic erosion product, which is very important for waste management and decommissioning work of pressurized water reactor (PWR) power plants. Recent measurement on the samples from the primary loop of HTR-10 indicates the existence of Co-60. In current paper, the preliminary experimental results in HTR-10 will be introduced, and the production mechanism of Co-60 in the pebble bed high temperature gas-cooled reactors will be summarized and compared with that in PWRs and Germany High Temperature Nuclear Reactor (AVR). The further experiments with decomposing the post-irradiation graphite spheres of HTR-10 are put forward, which will promote the further study to testify the production sources of Co-60 and be of great significance in the waste minimization and the decommissioning work of HTR-10. (author)

Seed germination of peanuts irradiated with cobalt ({sup 60}CO); Germinacao de sementes de amendoim irradiadas com cobalto ({sup 60}Co)

Energy Technology Data Exchange (ETDEWEB)

Alves, Niedja Marrize C.; Almeida, Francisco de Assis C.; Gomes, Josivanda P.; Pessoa, Elvira B., E-mail: niedjamarizze@yahoo.com.b, E-mail: josivanda@deag.ufcg.edu.b, E-mail: elvirabe@gmail.co [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Dept. de Engenharia Agricola; Leal, Artur S. Cavalcanti, E-mail: arturcleal@yahoo.com.b [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Dept. de Engenharia de Materiais

2010-07-01

This work was realized to evaluate the effect of gamma irradiation ({sup 60}Co) at doses 0, 0.50, 1.00, 1.50, 2.00, 2.50, 3.00 and 4.00 kGy, on germination of seeds of peanut, cultivar BR1. Irradiation Department of Nuclear, UFPE, where he received after the irradiation, they were stored in packing of PET and polyethylene braided with a time of 90 days. Through the results, obtained monthly, concluded that the dose of 0.5 kGy was effective in the germination of seeds of peanut, not affecting its power of germination and overcoming the witness within 30 to 60 days. (author)

Functionalization and magnetization of carbon nanotubes using Co-60 gamma-ray irradiation

Energy Technology Data Exchange (ETDEWEB)

Chen, C.Y.; Fu, M.J.; Tsai, C.Y. [Division of Isotope Application, Institute of Nuclear Energy Research, Atomic Energy Council, P.O. BOX 3-27 Longtan, Taoyuan County 32546, Taiwan (R.O.C.) (China); Lin, F.H. [Institute of Biomedical Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan (R.O.C.) (China); Chen, K.Y., E-mail: chenky@iner.gov.tw [Division of Isotope Application, Institute of Nuclear Energy Research, Atomic Energy Council, P.O. BOX 3-27 Longtan, Taoyuan County 32546, Taiwan (R.O.C.) (China)

2014-10-01

Functionalized magnetic carbon nanotubes (CNTs) can be used in the biological and biomedical fields as biosensors, drug delivery systems, etc., which makes research into processes for manufacturing modified CNTs quite important. In this paper, Co-60 gamma irradiation is shown to be an effective tool for fabricating functionalized and magnetized CNTs. After the Co-60 gamma irradiation, the presence of carboxylic functional groups on the CNT walls was confirmed by their Fourier transform infrared spectra, and the presence of Fe{sub 3}O{sub 4} was verified by the X-ray diffraction patterns. The functionalized and magnetized CNTs produced using Co-60 gamma irradiation have excellent dispersion properties. The techniques for functionalizing and magnetizing CNTs are introduced in this paper, and applications of the modified CNTs will be reported after more data are gathered. - Highlights: Dispersion ability of carbon nanotubes (CNTs) was improved by functionalization. CNTs were easily manipulated by precipitation of magnetic nanoparticles. Our product can be used as versatile biosensor substrate for biomarker screening.

The design of the Bulgaria rad waste repository

International Nuclear Information System (INIS)

Stefonova, I.; Petrov, I.; Navarro, M.; Sanchez, M.; Medinilla, G.

2012-01-01

In October 2011 a consortium composed by Westinghouse Engineering Spain SAU, ENRESA and DBE Technology GmbH was awarded a contract for the design of the Bulgaria rad waste repository. The facility, inspired in the spanish centre of El Cabril owned by ENRESA, will consist of a 66 reinforced concrete cells surface repository capable of receiving 18600 already conditioned waste containers of 20 t each, during 60 years, and the related auxiliary facilities and buildings. The project, representing a challenge because of the schedule and required level of detail, goes on fulfilling main milestones and getting customer satisfaction. (Author)

RadWorks Project

Data.gov (United States)

National Aeronautics and Space Administration — The RadWorks project's overarching objective is the maturation and demonstration of affordable, enabling solutions to the radiation-related challenges presented to...

Treatment plan quality of tri-Co-60 MR-IGRT system in comparison with that of VMAT

Energy Technology Data Exchange (ETDEWEB)

Park, Jong Min; Park, So Yeon; Kim, Jung In [Dept. of Nuclear Engineering, Seoul National University Hospital, Seoul (Korea, Republic of); Kim, Hak Jae; Wu, Hong Gyun [Dept. of Nuclear Engineering, Seoul National University College of Medicine, Seoul (Korea, Republic of)

2016-04-15

The ViewRay{sup TM} system combines a 0.35-T MR imaging system and a radiation therapy system using a total of three Co-60 sources. It can perform static intensity-modulated radiation therapy (IMRT) with multi-leaf collimators (MLCs) with leaf widths of 1.05 cm at the plane of isocenter, at source to axis distance (SAD) of 105 cm. Since the tri-Co-60 MR-IGRT system can acquire near-real-time cine sagittal MR images during treatment, automated respiratory gating can be performed based on these cine images, thus, the target margins for lung stereotactic ablative radiotherapy (SABR) could be reduced considerably by comparison with the internal tarvet volume (ITV) approach. we compared lung SABR treatment plans of the tri-Co-60 MR-IGRT system with gross tumor volume (GTV) to those of volumetric modulated arc therapy (VMAT) using TrueBeam STx™ (Varian Medical Systems, Palo Alto, CA) with ITV in this study. The plan quality of the target volume of the VMAT with ITV was better than that of the GTV-based tri-Co-60 MR-IGRT for lung SABR. No significant differences for OARs were observed between the tri-Co-60 MR-IGRT and VMAT. However, the plan quality of the tri-Co-60 MR-IGRT system was clinically acceptable. Despite the relatively poor plan quality of the tri-Co-60 MR-IGRT system, it still has the advantage of real-time monitoring of tumor motion during treatment.

Three additional genes involved in pyrimidine dimer removal in Saccharomyces cerevisiae: RAD7, RAD14, and MMS19

Energy Technology Data Exchange (ETDEWEB)

Prakash, L; Prakash, S

1979-01-01

The ability to remove ultraviolet (uv)-induced pyrimidine dimers from the nuclear DNA of yeast was examined in two radiation-sensitive (rad) mutants and one methyl methanesulfonate-sensitive (mms) mutant of the yeast Saccharomyces cerevisiae. The susceptibility of DNA from irradiated cells to nicking by an endonuclease activity prepared from crude extracts of Micrococcus luteus was used to measure the presence of dimers in DNA. The rad7, rad14, and mms19 mutants were found to be defective in their ability to remove uv-induced dimers from nuclear DNA. All three mutants belong to the same episatic group as the other mutants involved in excision-repair. All three mutants show enhanced uv-induced mutations. The rad 14 mutant also shows epistatic interactions with genes in the other two uv repair pathways.

Mobility and retention of Co-60 in soils in coastal areas

International Nuclear Information System (INIS)

Mahara, Y.; Kudo, A.

1980-01-01

The purpose of this study was to determine the mobility of radioactive cobalt ( 60 Co), a typical operating waste, in soils in coastal areas (where all Japanese commercial reactors are located). The results of this investigation may assist in evaluating a degree of safety for the future disposal of radioactive wastes underground. Freshwater and seawater were examined under both aerobic and anaerobic conditions by simulating the environmental conditions of the soils in coastal areas. More than 80% of 60 Co moves freely within soils covered by seawater under anaerobic conditions. Furthermore, the cobalt in the water phase can pass through a dialysis membrane with a pore size of 24 A. This indicates that the cobalt is either in ionic form or associated with materials of low molecular weight. On the other hand, more than 95% of 60 Co was retained by soils covered by freshwater under aerobic conditions. This cobalt, once fixed on soils, was not easily desorbed by seawater under anaerobic conditions. The results suggest that the mobility of cobalt disposed of underground is greatly enced by the initial environmental conditions in the soils in coastal areas. (H.K.)

HiRadMat: materials under scrutiny

CERN Multimedia

Anaïs Schaeffer

2011-01-01

CERN's new facility, HiRadMat (High Radiation to Materials), which is designed to test materials for the world's future particle accelerators, should be operational and welcoming its first experiments by the end of the year.   The HiRadMat facility, located in the TNC tunnel. The materials used in the LHC and its experiments are exposed to very high-energy particles. The LHC machine experts obviously didn't wait for the first collisions in the world's most powerful accelerator to put the materials through their paces - the equipment was validated following a series of stringent tests. And these tests will get even tougher now, with the arrival of HiRadMat. The tunnel that formerly housed the West Area Neutrino Facility (WANF) has been completely revamped to make way for CERN's latest facility, HiRadMat. Supported by the Radioprotection service, a team from the Engineering (EN) Department handled the dismantling operations from October 2009 to December 2010. "We could only work on disman...

Development of dosimeters with rad-hard silicon diodes for high dose dosimetry

International Nuclear Information System (INIS)

Camargo, Fabio de

2009-01-01

In this work we report on results obtained with rad-hard Standard Float Zone (FZ), Diffusion Oxygenated Float Zone (DOFZ) and Magnetic Czochralski (MCz) silicon diodes in gamma radiation processing dosimetry. These p ± n-n + junction devices were manufactured by Okmetic Oyj. (Vantaa, Finland) and processed by the Microelectronics Center of Helsinki University of Technology in the framework of the CERN RD50 Collaboration. The dosimetric probes, based on FZ, DOFZ and M Cz devices, were designed to operate without bias voltage in the direct current mode as on-line radiation dosimeter. The irradiations were performed in the Radiation Technology Center (CTR) at IPEN-CNEN/SP using a 60 Co source (Gamma cell 220 - Nordion) with a dose rate around of 2.4 kGy/h. The current response of each diode was measured as a function of the exposure time in steps from 5 kGy up to 50 kGy to achieve a total absorbed dose of 275 kGy. The results obtained showed a significant decrease in the photocurrent generated in all devices for total absorbed doses higher than approximately 25 kGy. To reduce this effect, the samples were pre-irradiated with 60 Co gamma rays at 700 kGy in order to saturate the trap production in the diode's sensitive volume. After pre-irradiation, despite of being less sensitive, all devices exhibited more stable photocurrent signals, even for total absorbed doses of 275 kGy. To monitor possible gamma radiation damage effects produced on the diodes, their dynamic leakage current and capacitance were measured as a function of the absorbed dose. (author)

The comparison of Co-60 and 4MV photons matching dosimetry during half-beam technique

International Nuclear Information System (INIS)

Cakir, Aydin; Bilge, Hatice; Dadasbilge, Alpar; Kuecuecuek, Halil; Okutan, Murat; Merdan Fayda, Emre

2005-01-01

In this phantom study, we tried to compare matching dosimetry differences between half-blocking of Co-60 and asymmetric collimation of the 4MV photons during craniospinal irradiation. The dose distributions are compared and discussed. Firstly, some gaps with different sizes are left between cranial and spinal field borders. Secondly, the fields are overlapped in the same sizes. We irradiate the films located in water-equivalent solid phantoms with Co-60 and 4MV photon beams. This study indicates that the field placement errors in +/- 1mm are acceptable for both Co-60 and 4MV photon energies during craniospinal irradiation with half-beam block technique. Within these limits the dose variations are specified in +/- 5%. However, the setup errors that are more than 1mm are unacceptable for both asymmetric collimation of 4MV photon and half-blocking of Co-60

A comparison between rad-hard float zone silicon diodes as gamma dosimeter in radiation processing

Energy Technology Data Exchange (ETDEWEB)

Camargo, Fábio de [Amazônia Azul Tecnologias de Defesa S.A. (AMAZUL), São Paulo, SP (Brazil); Gonçalves, Josemary A.C.; Bueno, Carmen C., E-mail: dcamargo@gmail.com, E-mail: ccbueno@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil)

2017-07-01

In this work, we report on the results obtained with rad-hard Standard Float Zone (STFZ) and Diffused Oxygenated Float Zone (DOFZ) silicon diodes in radiation processing dosimetry. The dosimetric probes were designed to operate in the direct current mode, as on-line radiation dosimeter. The irradiation of the samples was performed using a {sup 60}Co source with a dose rate of almost 2.4 kGy/h. The current response of each diode was measured as a function of the exposure time in steps from 5 kGy up to 50 kGy to achieve a total absorbed dose of 275 kGy. In this dose range it is observed a significant decrease in the photocurrent generated in both devices due to gamma radiation defects produced in their active volumes. To mitigate this effect, the samples were pre-irradiated with {sup 60}Co gamma rays at 700 kGy. Despite of being less sensitive, these devices presented stable and reproducible current signals with a relative sensitivity decrease of about 19% within the whole range of dose studied. The dose-response curves of the pre-irradiated diodes showed quadratic behavior with correlation coefficient higher than 0.9999 for total absorbed dose up to 275 kGy. The comparison of the FZ and DOFZ responses evidenced that the latter was slightly superior to the first. However, it is important to note that all pre-irradiated diodes can be used as gamma dosimeters in radiation processing applications. (author)

A comparison between rad-hard float zone silicon diodes as gamma dosimeter in radiation processing

International Nuclear Information System (INIS)

Camargo, Fábio de; Gonçalves, Josemary A.C.; Bueno, Carmen C.

2017-01-01

In this work, we report on the results obtained with rad-hard Standard Float Zone (STFZ) and Diffused Oxygenated Float Zone (DOFZ) silicon diodes in radiation processing dosimetry. The dosimetric probes were designed to operate in the direct current mode, as on-line radiation dosimeter. The irradiation of the samples was performed using a 60 Co source with a dose rate of almost 2.4 kGy/h. The current response of each diode was measured as a function of the exposure time in steps from 5 kGy up to 50 kGy to achieve a total absorbed dose of 275 kGy. In this dose range it is observed a significant decrease in the photocurrent generated in both devices due to gamma radiation defects produced in their active volumes. To mitigate this effect, the samples were pre-irradiated with 60 Co gamma rays at 700 kGy. Despite of being less sensitive, these devices presented stable and reproducible current signals with a relative sensitivity decrease of about 19% within the whole range of dose studied. The dose-response curves of the pre-irradiated diodes showed quadratic behavior with correlation coefficient higher than 0.9999 for total absorbed dose up to 275 kGy. The comparison of the FZ and DOFZ responses evidenced that the latter was slightly superior to the first. However, it is important to note that all pre-irradiated diodes can be used as gamma dosimeters in radiation processing applications. (author)

Assessing filtering of mountaintop CO2 mole fractions for application to inverse models of biosphere-atmosphere carbon exchange

Directory of Open Access Journals (Sweden)

S. L. Heck

2012-02-01

Full Text Available There is a widely recognized need to improve our understanding of biosphere-atmosphere carbon exchanges in areas of complex terrain including the United States Mountain West. CO2 fluxes over mountainous terrain are often difficult to measure due to unusual and complicated influences associated with atmospheric transport. Consequently, deriving regional fluxes in mountain regions with carbon cycle inversion of atmospheric CO2 mole fraction is sensitive to filtering of observations to those that can be represented at the transport model resolution. Using five years of CO2 mole fraction observations from the Regional Atmospheric Continuous CO2 Network in the Rocky Mountains (Rocky RACCOON, five statistical filters are used to investigate a range of approaches for identifying regionally representative CO2 mole fractions. Test results from three filters indicate that subsets based on short-term variance and local CO2 gradients across tower inlet heights retain nine-tenths of the total observations and are able to define representative diel variability and seasonal cycles even for difficult-to-model sites where the influence of local fluxes is much larger than regional mole fraction variations. Test results from two other filters that consider measurements from previous and following days using spline fitting or sliding windows are overly selective. Case study examples showed that these windowing-filters rejected measurements representing synoptic changes in CO2, which suggests that they are not well suited to filtering continental CO2 measurements. We present a novel CO2 lapse rate filter that uses CO2 differences between levels in the model atmosphere to select subsets of site measurements that are representative on model scales. Our new filtering techniques provide guidance for novel approaches to assimilating mountain-top CO2 mole fractions in carbon cycle inverse models.

Behavior of the sorption of {sup 60} Co in aqueous solution on inorganic materials as function of p H; Comportamiento de la sorcion del {sup 60} Co en solucion acuosa sobre materiales inorganicos como una funcion del pH

Energy Technology Data Exchange (ETDEWEB)

Granados, F.; Bulbulian, S.; Solache R, M. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico); Bertin, V. [UAM-I, 09340 Mexico D.F. (Mexico)

2004-07-01

The sorption of the {sup 60} Co is evaluated in aqueous solution on Mg O, MnO{sub 2}, TiO{sub 2}, Sn O, activated carbon and hydrotalcite calcined as a function of the p H, using the method for lots and quantifying at the {sup 60} Co for gamma spectrometry. Likewise it was explained the one behavior of the sorption of the {sup 60} Co in the materials with base in the chemical species of this radioactive isotope in aqueous solution. The chemical species of the {sup 60} Co in solution were identified by electrophoresis of high voltage for the different p H values. It was found that under the experimental conditions, the {sup 60} Co showed a significant sorption on MnO{sup 2}, TiO{sup 2} and activated carbon. On the other hand, in Mg O, Sn O and calcined hydrotalcite also was observed a sorption, although in smaller quantities. The studied hydrated metallic oxides retained the {sup 60} Co for ion exchange via. It was found that the {sup 60} Co was present as a cationic specie to p H 1, 3, 5 and 7 and like a neutral specie to alkaline p H. (Author)

Effect of Orbital Hybridization on Spin-Polarized Tunneling across Co/C60 Interfaces.

Science.gov (United States)

Wang, Kai; Strambini, Elia; Sanderink, Johnny G M; Bolhuis, Thijs; van der Wiel, Wilfred G; de Jong, Michel P

2016-10-26

The interaction between ferromagnetic surfaces and organic semiconductors leads to the formation of hybrid interfacial states. As a consequence, the local magnetic moment is altered, a hybrid interfacial density of states (DOS) is formed, and spin-dependent shifts of energy levels occur. Here, we show that this hybridization affects spin transport across the interface significantly. We report spin-dependent electronic transport measurements for tunnel junctions comprising C 60 molecular thin films grown on top of face-centered-cubic (fcc) epitaxial Co electrodes, an AlO x tunnel barrier, and an Al counter electrode. Since only one ferromagnetic electrode (Co) is present, spin-polarized transport is due to tunneling anisotropic magnetoresistance (TAMR). An in-plane TAMR ratio of approximately 0.7% has been measured at 5 K under application of a magnetic field of 800 mT. The magnetic switching behavior shows some remarkable features, which are attributed to the rotation of interfacial magnetic moments. This behavior can be ascribed to the magnetic coupling between the Co thin films and the newly formed Co/C 60 hybridized interfacial states. Using the Tedrow-Meservey technique, the tunnel spin polarization of the Co/C 60 interface was found to be 43%.

A Rad53 independent function of Rad9 becomes crucial for genome maintenance in the absence of the Recq helicase Sgs1.

Directory of Open Access Journals (Sweden)

Ida Nielsen

Full Text Available The conserved family of RecQ DNA helicases consists of caretaker tumour suppressors, that defend genome integrity by acting on several pathways of DNA repair that maintain genome stability. In budding yeast, Sgs1 is the sole RecQ helicase and it has been implicated in checkpoint responses, replisome stability and dissolution of double Holliday junctions during homologous recombination. In this study we investigate a possible genetic interaction between SGS1 and RAD9 in the cellular response to methyl methane sulphonate (MMS induced damage and compare this with the genetic interaction between SGS1 and RAD24. The Rad9 protein, an adaptor for effector kinase activation, plays well-characterized roles in the DNA damage checkpoint response, whereas Rad24 is characterized as a sensor protein also in the DNA damage checkpoint response. Here we unveil novel insights into the cellular response to MMS-induced damage. Specifically, we show a strong synergistic functionality between SGS1 and RAD9 for recovery from MMS induced damage and for suppression of gross chromosomal rearrangements, which is not the case for SGS1 and RAD24. Intriguingly, it is a Rad53 independent function of Rad9, which becomes crucial for genome maintenance in the absence of Sgs1. Despite this, our dissection of the MMS checkpoint response reveals parallel, but unequal pathways for Rad53 activation and highlights significant differences between MMS- and hydroxyurea (HU-induced checkpoint responses with relation to the requirement of the Sgs1 interacting partner Topoisomerase III (Top3. Thus, whereas earlier studies have documented a Top3-independent role of Sgs1 for an HU-induced checkpoint response, we show here that upon MMS treatment, Sgs1 and Top3 together define a minor but parallel pathway to that of Rad9.

Mutagenesis of the somaclones in vitro of cut roses by 60Co γ-rays irradiation

International Nuclear Information System (INIS)

Qu Suping; Su Yan; Wang Lihua; Tang Kaixue; Wang Jihua; Zhang Hao

2009-01-01

Mutagenesis of cut rose in vitro irradiated by 60 Co γ-rays was studied. The callus of leaves and regenerations adventitious bud was used as the explants for mutagenesis. Effect of 60 Co γ-rays irradiation on the callus's regeneration rate, adventitious bud's multiplication rate and vegetal status were studied. The results showed that the regeneration frequency of callus was decreased by 60 Co γ-rays irradiation. The regenerations adventitious bud was the better experimental materials compared with the callus of leaves. The lethal dose was 122 Gy and the semi-lethal dose was 76 Gy according to the regression equation. The appropriate dose on adventitious bud by irradiation rays was 50-60 Gy. (authors)

RadNet Air Quality (Fixed Station) Data

Data.gov (United States)

U.S. Environmental Protection Agency — RadNet is a national network of monitoring stations that regularly collect air for analysis of radioactivity. The RadNet network, which has stations in each State,...

Shear Stress in Nickel and Ni-60Co under One-Dimensional Shock Loading

International Nuclear Information System (INIS)

Workman, A.; Wallwork, A.; Meziere, Y. J. E.; Millett, J. C. F.; Bourne, N. K.

2006-01-01

The dynamic response of pure nickel (Ni), and its alloy, Ni-60Co (by weight %), has been investigated during one-dimensional shock loading. Few materials' properties are different and the only significantly altered feature is the reduced stacking fault energy (SFE) for the Ni-60Co. This paper considers the effect of this reduced SFE on the shear strength. Data (in terms of shock stress, particle velocity and shock velocity) are also presented. The influence on the shear stress, τ of cobalt additions in nickel are then investigated and presented. Results indicate that the lateral stress is increasing in both materials with the increasing impact stress. The shear stress was found to be higher in the nickel than in the Ni-60Co. The progressive decrease of the lateral stress noted during loading indicates a complex mechanism of deformation behind the shock front

Application of feedback system in optimizing safety performance of "6"0Co radiation apparatus

International Nuclear Information System (INIS)

Luo Shishi; Wang Zegang; Ge Cailin; Ma Fei; Gong Zheng

2001-01-01

To ensure "6"0Co apparatus runs safely applying the basic principle of cybernetics to optimizing safety performance was studied. Through several decades of practice the cybernetic system is shown to be safe and effective, and it will be an example for small and middle "6"0Co radiation apparatus to rebuild the cybernetic system. (authors)

Analysis of ZPPR experiments supporting production of 60Co in FFTF

International Nuclear Information System (INIS)

Wootan, D.W.; Carter, L.L.; Rawlins, J.A.; Schaefer, R.W.; Maddison, D.W.

1987-01-01

An effort to expand the irradiation mission of the Fast Flux Test Facility (FFTF) beyond testing fuels and materials for the liquid-metal reactor (LMR) program included a study of the feasibility of producing commercial quantities of 60 Co. The 60 Co would be produced by neutron capture in assemblies containing an array of natural cobalt pins and hydrogen-bearing moderator pins located at the periphery of the FFTF core. Adding hydrogenous material to the assemblies enhances 60 Co production by slowing neutrons into energy ranges where the 59 Co capture cross section is higher. Some of the moderated neutrons leak from the moderated region to adjacent fuel regions, increasing local fission rates. In order to validate calculated fission rates and establish calculational biases and uncertainties, experiments were conducted in the zero-power plutonium reactor (ZPPR) to measure fission rates in fuel regions adjacent to a mock-up of a cobalt production assembly. The ZPPR experiment and analyses provided the technical basis for irradiating hydride-moderated assemblies in FFTF and a cobalt production cycle of FFTF with generally good agreement between measured and predicted reactivity worth and outlet temperatures in adjacent fuel assemblies. This experiment provides a benchmark configuration of a hydrogenous assembly in a fast reactor, with emphasis on the effect of the hydrogen on adjacent fuel. It is anticipated there will be other applications of hydride moderation in the development of future isotope production missions in FFTF

Simulation of the GCR spectrum in the Mars curiosity rover's RAD detector using MCNP6.

Science.gov (United States)

Ratliff, Hunter N; Smith, Michael B R; Heilbronn, Lawrence

2017-08-01

The paper presents results from MCNP6 simulations of galactic cosmic ray (GCR) propagation down through the Martian atmosphere to the surface and comparison with RAD measurements made there. This effort is part of a collaborative modeling workshop for space radiation hosted by Southwest Research Institute (SwRI). All modeling teams were tasked with simulating the galactic cosmic ray (GCR) spectrum through the Martian atmosphere and the Radiation Assessment Detector (RAD) on-board the Curiosity rover. The detector had two separate particle acceptance angles, 4π and 30 ° off zenith. All ions with Z = 1 through Z = 28 were tracked in both scenarios while some additional secondary particles were only tracked in the 4π cases. The MCNP6 4π absorbed dose rate was 307.3 ± 1.3 µGy/day while RAD measured 233 µGy/day. Using the ICRP-60 dose equivalent conversion factors built into MCNP6, the simulated 4π dose equivalent rate was found to be 473.1 ± 2.4 µSv/day while RAD reported 710 µSv/day. Copyright © 2017 The Committee on Space Research (COSPAR). Published by Elsevier Ltd. All rights reserved.

Tunable solvation effects on the size-selective fractionation of metal nanoparticles in CO2 gas-expanded solvents.

Science.gov (United States)

Anand, Madhu; McLeod, M Chandler; Bell, Philip W; Roberts, Christopher B

2005-12-08

This paper presents an environmentally friendly, inexpensive, rapid, and efficient process for size-selective fractionation of polydisperse metal nanoparticle dispersions into multiple narrow size populations. The dispersibility of ligand-stabilized silver and gold nanoparticles is controlled by altering the ligand tails-solvent interaction (solvation) by the addition of carbon dioxide (CO2) gas as an antisolvent, thereby tailoring the bulk solvent strength. This is accomplished by adjusting the CO2 pressure over the liquid, resulting in a simple means to tune the nanoparticle precipitation by size. This study also details the influence of various factors on the size-separation process, such as the types of metal, ligand, and solvent, as well as the use of recursive fractionation and the time allowed for settling during each fractionation step. The pressure range required for the precipitation process is the same for both the silver and gold particles capped with dodecanethiol ligands. A change in ligand or solvent length has an effect on the interaction between the solvent and the ligand tails and therefore the pressure range required for precipitation. Stronger interactions between solvent and ligand tails require greater CO2 pressure to precipitate the particles. Temperature is another variable that impacts the dispersibility of the nanoparticles through changes in the density and the mole fraction of CO2 in the gas-expanded liquids. Recursive fractionation for a given system within a particular pressure range (solvent strength) further reduces the polydispersity of the fraction obtained within that pressure range. Specifically, this work utilizes the highly tunable solvent properties of organic/CO2 solvent mixtures to selectively size-separate dispersions of polydisperse nanoparticles (2 to 12 nm) into more monodisperse fractions (+/-2 nm). In addition to providing efficient separation of the particles, this process also allows all of the solvent and

Mechanisms of60Co uptake and loss by Scenedesmus obliquus and transfer to two benthic organisms

International Nuclear Information System (INIS)

Nucho, R.

1989-10-01

The affinity of Scenedesmus obliquus for 60 Co has been confirmed under various experimental conditions allowing for the age of cultures, the physiological state of the cells, the radioactivity level and stable cobalt concentration in the medium, and the acute or periodic nature of the contamination. The dry weight 60 Co concentration factor may reach 4x10 4 in LCO culture medium and is about 10 4 in natural water. 60 Co uptake by algae is a 95% passive phenomenon, initiated by radionuclide absorption on the cell walls and followed by intracellular diffusion in accordance with Fick's law. From the initial cationic form, radiocobalt develops anion forms at a rate proportional to the algal biomass, resulting in lower contamination of old and dense cultures. After transfer in natural or artificial nonradioctive medium, 60 Co is eliminated by Scenedesmus obliquus, mainly as Co 2+ ions, according to a two-phase exponential process with two biological half-lives. The study of radioactive cobalt transfer from algae to gammarids and to midge larvae reveals the extend to which phytoplankton predominate over water and sediment in contaminating these two organisms. The total 60 Co uptake depends significantly on whether the cells are incorporated in or deposited on the sediment. No biomagnification phenomenon of the radionuclide was found in any case, as the transfer factor was less than 1. Depuration of 60 Co by organisms involved a two-phase exponential process regardless of whether uptake occured directly or from food. The presence of sediment appears to reduce the 60 Co desorption rate, but from 85 to 95% of the initial quantity is eliminated. This percentage does not depend on the transfer pathway or the presence of organic matter, and indicates very slight assimilation of radiocobalt ingested with algal cells [fr

Dosimetric Consistency of Co-60 Teletherapy Unit- a ten years Study.

Science.gov (United States)

Baba, Misba H; Mohib-Ul-Haq, M; Khan, Aijaz A

2013-01-01

The goal of the Radiation standards and Dosimetry is to ensure that the output of the Teletherapy Unit is within ±2% of the stated one and the output of the treatment dose calculation methods are within ±5%. In the present paper, we studied the dosimetry of Cobalt-60 (Co-60) Teletherapy unit at Sher-I-Kashmir Institute of Medical Sciences (SKIMS) for last 10 years. Radioactivity is the phenomenon of disintegration of unstable nuclides called radionuclides. Among these radionuclides, Cobalt-60, incorporated in Telecobalt Unit, is commonly used in therapeutic treatment of cancer. Cobalt-60 being unstable decays continuously into Ni-60 with half life of 5.27 years thereby resulting in the decrease in its activity, hence dose rate (output). It is, therefore, mandatory to measure the dose rate of the Cobalt-60 source regularly so that the patient receives the same dose every time as prescribed by the radiation oncologist. The under dosage may lead to unsatisfactory treatment of cancer and over dosage may cause radiation hazards. Our study emphasizes the consistency between actual output and output obtained using decay method. The methodology involved in the present study is the calculations of actual dose rate of Co-60 Teletherapy Unit by two techniques i.e. Source to Surface Distance (SSD) and Source to Axis Distance (SAD), used for the External Beam Radiotherapy, of various cancers, using the standard methods. Thereby, a year wise comparison has been made between average actual dosimetric output (dose rate) and the average expected output values (obtained by using decay method for Co-60.). The present study shows that there is a consistency in the average output (dose rate) obtained by the actual dosimetry values and the expected output values obtained using decay method. The values obtained by actual dosimetry are within ±2% of the expected values. The results thus obtained in a year wise comparison of average output by actual dosimetry done regularly as a part of

Behavior of the sorption of 60 Co in aqueous solution on inorganic materials as function of p H

International Nuclear Information System (INIS)

Granados, F.; Bulbulian, S.; Solache R, M.; Bertin, V.

2004-01-01

The sorption of the 60 Co is evaluated in aqueous solution on Mg O, MnO 2 , TiO 2 , Sn O, activated carbon and hydrotalcite calcined as a function of the p H, using the method for lots and quantifying at the 60 Co for gamma spectrometry. Likewise it was explained the one behavior of the sorption of the 60 Co in the materials with base in the chemical species of this radioactive isotope in aqueous solution. The chemical species of the 60 Co in solution were identified by electrophoresis of high voltage for the different p H values. It was found that under the experimental conditions, the 60 Co showed a significant sorption on MnO 2 , TiO 2 and activated carbon. On the other hand, in Mg O, Sn O and calcined hydrotalcite also was observed a sorption, although in smaller quantities. The studied hydrated metallic oxides retained the 60 Co for ion exchange via. It was found that the 60 Co was present as a cationic specie to p H 1, 3, 5 and 7 and like a neutral specie to alkaline p H. (Author)

Effect of 60Co γ-ray irradiation on human platelets

International Nuclear Information System (INIS)

Wu Guoxin; Zhao Yiming; Ruan Changgeng

1992-01-01

Human platelet-rich plasma was irradiated with various doses (0, 1.25, 2.5, 5, 10, 20, 40 Gy) of 60 Co γ-rays in order to observe the changes of metabolites and the release of internal substance of platelets. At the dose of 5 Gy, alpha-granule membrane protein (GMP-140) molecules expressed on the surface of platelets increased significantly, while glycoproteins (GP) Ib and IIIa did not change apparently; at the dose as low as of 2.5 Gy, thromboxane B 2 production in plasma was remarkably increased; and, at the dose of over 5 Gy, the concentration of von Willebrand factor increased with increasing doses as in the case of GMP-140 molecules. These results indicate that platelets can be activated in vitro when the dose of 60 Co γ-rays exceeds 5 Gy

RadNet Air Data From Sacramento, CA

Science.gov (United States)

This page presents radiation air monitoring and air filter analysis data for Sacramento, CA from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

RadNet Air Data From Honolulu, HI

Science.gov (United States)

This page presents radiation air monitoring and air filter analysis data for Honolulu, HI from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

RadNet Air Data From Houston, TX

Science.gov (United States)

This page presents radiation air monitoring and air filter analysis data for Houston, TX from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

RadNet Air Data From Austin, TX

Science.gov (United States)

This page presents radiation air monitoring and air filter analysis data for Austin, TX from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

RadNet Air Data From Orlando, FL

Science.gov (United States)

This page presents radiation air monitoring and air filter analysis data for Orlando, FL from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

Lesson from a 60Co source radiation accident

International Nuclear Information System (INIS)

Guo Yong; Zhang Wenzhong

2002-01-01

A serious radiation accident happened an a 60 Co irradiation facility in Shanghai. 7 workers were uniformly exposed acutely. An investigation was done after the accident and a conclusion was achieved that the irregular operation was the direct reason for the accident. The operation of these workers did not comply with the requirements specified in the national standards-- 60 irradiation facility>> which demands that the examination should be done every day before operation, and the irradiation facility does not stop running when the auto-lock safety system on that facility has been removed. Some lessons should be drawn from the accident: popularizing the culture of safety, enhancing the law of safety, and ensuring the operation of radiation devices within the demands of safety

Effects of the rad52 gene on recombination in Saccharomyces cerevisiae

International Nuclear Information System (INIS)

Prakash, S.; Prakash, L.; Burke, W.; Montelone, B.A.

1980-01-01

Effects of the rad 52 mutation in Saccharomyces cerevisiae on meiotic, γ-ray-induced, uv-induced and spontaneous mitotic recombination were studied. The rad52/rad52 diploids undergo premeiotic DNA synthesis; sporulation occurs but inviable spores are produced. Both intra and intergenic recombination during meiosis were examined in cells transferred from sporulation medium to vegetative medium at different time intervals. No intragenic recombination was observed at the his1-1/his1-315 and trp-5-2/trp5-48 heteroalleles. Gene-centromere recombination also was not observed in rad/52/rad52 diploids. No γ-ray- or uv-induced intragenic mitotic recombination is seen in rad52/rad52 diploids. The rate of spontaneous mitotic recombination is lowered five-fold at the his1-1/his1-315 and leu1-c/leu1-12 heteroalleles. Spontaneous reversion rates of both his1-1 and his1-315 were elevated 10 to 20 fold in rad52/rad52 diploids. The RAD52 gene function is required for spontaneous mitotic recombination, uv- and γ-ray-induced mitotic recombination and mitotic recombination

Uptake and release of 54Mn and 60Co in Fucus vesiculosus L. and its epiphytes

International Nuclear Information System (INIS)

Carlson, Lena

1990-01-01

Fucus vesiculosus with epiphytic Pilayella littoralis was collected at a locality with low contamination of 54 Mn and 60 Co and transplanted at a locality in the vicinity of the Barsebaeck nuclear power plant in the Oeresund, southern Sweden and vice versa. The highest uptake of the radionuclides discharged from the nuclear power plant was observed in the filamentous epiphytic P. littoralis and difference in uptake of 60 Co was also observed between tissues of different ages in F. vesiculosus, with slightly higher uptake in the new vegetative fronds. P. Littoralis was succeded as epiphyte by Enteromorpha intestinalis and Cladophora sp. and the highest uptake of both radionuclides was observed in Cladophora sp. Compared with the native Fucus plants at Barsebaeck, the transplanted Fucus plants showed about the same activity concentrations of 54 Mn while the 60 Co concentrations in the transplanted plants were higher than in the native plants after about four months. The release of 54 Mn and 60 Co was most rapid in the epiphytic P. littoralis. Biological half-lives calculated from an exponential relation were found to be about 10 days for p. littoralis and about 40 days for new vegetative fronds of F vesiculosus. Longer half-lives were found for 1-year-old tissues of F. vesiculosus: about 95 and 165 days for 54 Mn and 60 Co, respectively. One year after transplantation about 30% of the initial activity concentration of 60 Co was still present in the older part of the F. vesiculosus plants. The differences in uptake of 54 Mn and 60 Co between the algal species illustrates the difficulties encountered in comparing results from different algal species. (author)

Rad9 Has a Functional Role in Human Prostate Carcinogenesis

Science.gov (United States)

Zhu, Aiping; Zhang, Charles Xia; Lieberman, Howard B.

2013-01-01

Prostate cancer is currently the most common type of neoplasm found in American men, other than skin cancer, and is the second leading cause of cancer death in males. Because cell cycle checkpoint proteins stabilize the genome, the relationship of one such protein, Rad9, to prostate cancer was investigated. We found that four prostate cancer cell lines (CWR22, DU145, LNCaP, and PC-3), relative to PrEC normal prostate cells, have aberrantly high levels of Rad9 protein. The 3′-end region of intron 2 of Rad9 in DU145 cells is hypermethylated at CpG islands, and treatment with 5′-aza-2′-deoxycytidine restores near-normal levels of methylation and reduces Rad9 protein abundance. Southern blot analyses indicate that PC-3 cells contain an amplified Rad9 copy number. Therefore, we provide evidence that Rad9 levels are high in prostate cancer cells due at least in part to aberrant methylation or gene amplification. The effectiveness of small interfering RNA to lower Rad9 protein levels in CWR22, DU145, and PC-3 cells correlated with reduction of tumorigenicity in nude mice, indicating that Rad9 actively contributes to the disease. Rad9 protein levels were high in 153 of 339 human prostate tumor biopsy samples examined and detectable in only 2 of 52 noncancerous prostate tissues. There was a strong correlation between Rad9 protein abundance and cancer stage. Rad9 protein level can thus provide a biomarker for advanced prostate cancer and is causally related to the disease, suggesting the potential for developing novel diagnostic, prognostic, and therapeutic tools based on detection or manipulation of Rad9 protein abundance. PMID:18316588

60Co, 63Ni and 94Nb soil-to-plant transfer in pot experiments

International Nuclear Information System (INIS)

Gerzabek, M.H.; Mohamad, S.A.; Mueck, K.; Horak, O.

1995-01-01

Soil-to-plant transfer factors for 60 Co, 63 Ni and 94 Nb were obtained via pot experiments with a Dystric Cambisol and a Calcic Chernozem, both from Lower Austria. Investigated plants were greenrape (Brassica napus oleifera L.), bean (Phaseolus vulgaris L.) and winter wheat (Triticum aestivum L.). The soil-to-plant transfer factors decreased from 63 Ni to 60 Co and 94 Nb. Mean values from all experiments ranged from 1.12 ( 63 Ni) to 0.0045 ( 94 Nb). The transfer values obtained for 60 Co and 63 Ni are comparable to literature values, but 94 Nb-transfer seems to be lower than previous estimates. All radionuclides showed differences between plant species and plant organs. Transfer values were also dependent on the soil type. (author)

Inhibition of MAPK and PKC pathways by 60Co γ-radiation in cultured vascular smooth muscle cells

International Nuclear Information System (INIS)

Jia Guanghong; Ma Yexin; Xiao Jianming

2002-01-01

Objective: To investigate the signal transduction pathways inhibited by 60 Co γ-radiation in cultured vascular smooth muscle cells (VSMC). Methods: The cultured VSMC were irradiated with 60 Co γ-radiation of 3.5, 7.0 and 14 Gy respectively. VSMC proliferation was measured by 3 H-TdR incorporation, while PKC, MAPK activities were determined by radioactivity assay. Results: Proliferation of VSMC was inhibited by 7.0, 14 Gy 60 Co γ-irradiation and the activities of PKC, MAPK were decreased significantly. Conclusion: Inhibitory effect of 7.0, 14 Gy 60 Co γ-irradiation on proliferation of VSMC might be resulted from decrease of the activity of PKC, MAPK

RAD51B in Familial Breast Cancer

OpenAIRE

Pelttari, L.M.; Khan, S.; et al.,

2016-01-01

Common variation on 14q24.1, close to RAD51B, has been associated with breast cancer: rs999737\\ud and rs2588809 with the risk of female breast cancer and rs1314913 with the risk of male breast\\ud cancer. The aim of this study was to investigate the role of RAD51B variants in breast cancer\\ud predisposition, particularly in the context of familial breast cancer in Finland. We sequenced the\\ud coding region of RAD51B in 168 Finnish breast cancer patients from the Helsinki region for\\ud identifi...

RAD51B in familial breast cancer

OpenAIRE

Pelttari, LM; Khan, S; Vuorela, M; Kiiski, JI; Vilske, S; Nevanlinna, V; Ranta, S; Schleutker, J; Winqvist, R; Kallioniemi, A; Dörk, T; Bogdanova, NV; Figueroa, J; Pharoah, PDP; Schmidt, MK

2016-01-01

Common variation on 14q24.1, close to RAD51B, has been associated with breast cancer: rs999737 and rs2588809 with the risk of female breast cancer and rs1314913 with the risk of male breast cancer. The aim of this study was to investigate the role of RAD51B variants in breast cancer predisposition, particularly in the context of familial breast cancer in Finland. We sequenced the coding region of RAD51B in 168 Finnish breast cancer patients from the Helsinki region for identification of possi...

Co60 and Cs137 gamma radiation effects on textured bscco Superconducting fibers

International Nuclear Information System (INIS)

Leyva Fabelo, A.; Bouza Dominguez, J.; Cruz Inclan, Crlos M.

2001-01-01

Bi2Sr2CaCu2Ox superconducting fibers synthesized by solid state reaction and textured by the method of zonal laser ablation were irradiated with gamma rays of 1.25 MeV and 662 keV and studied the behavior of some of its properties with the exposition dose. The measurements of dynamic magnetic susceptibility were used for the characterization of the samples. It was observed that for the dose of up to 600 kGy in the case of the Co60 and until 500 mGy for the Cs137, the fibers preserve its superconducting intragrain properties. It is an evidence of the high resistance of the material to the radiacional damage. In all the cases were verified that with the increase of the dose the Ton of the transition grows. Two possible mechanisms that play the most important role in this effect are explained in the text. The ac measurements allowed to verified the increasing behavior of the superconducting volume fraction in the sample with the exposition dose

137Cs, 60Co and 40K uptake by lettuce plants in two distributions of soil contamination

International Nuclear Information System (INIS)

Quinto, Francesca; Sabbarese, Carlo; Visciano, Lidianna; Terrasi, Filippo; D'Onofrio, Antonio

2009-01-01

137 Cs and 60 Co, two of the radionuclides more representative of discharges from nuclear facilities, are of interest for radiological protections because of their great mobility in biosphere and affinity with biological systems. The aim of the present work is the investigation of the possible influence of the vertical distribution of 137 Cs and 60 Co in soil upon their uptake by lettuce as function of plant's growth. An experiment ad hoc has been carried out in field conditions. The results show that (i) the transfer of 137 Cs and 60 Co from soil to lettuce is independent by their distribution in soil, (ii) the soil-plant transfer factors of 137 Cs and 60 Co show a similar trend vs. growth stage, (iii) the 40 K transfer factor trend is different from those of anthropogenic radionuclides, and (iv) 137 Cs and 60 Co specific activities are about 1 Bq/kg, in the mature vegetable with soil activity from 9 to 21 kBq/m 2 .

Quantum plasmon and Rashba-like spin splitting in self-assembled Co x C60 composites with enhanced Co content (x > 15)

Science.gov (United States)

Lavrentiev, Vasily; Chvostova, Dagmar; Stupakov, Alexandr; Lavrentieva, Inna; Vacik, Jiri; Motylenko, Mykhaylo; Barchuk, Mykhailo; Rafaja, David; Dejneka, Alexandr

2018-04-01

Driving by interplay between plasmonic and magnetic effects in organic composite semiconductors is a challenging task with a huge potential for practical applications. Here, we present evidence of a quantum plasmon excited in the self-assembled Co x C60 nanocomposite films with x > 15 (interval of the Co cluster coalescence) and analyse it using the optical absorption (OA) spectra. In the case of Co x C60 film with x = 16 (LF sample), the quantum plasmon generated by the Co/CoO clusters is found as the 1.5 eV-centred OA peak. This finding is supported by the establishment of four specific C60-related OA lines detected at the photon energies E p > 2.5 eV. Increase of the Co content up to x = 29 (HF sample) leads to pronounced enhancement of OA intensity in the energy range of E p > 2.5 eV and to plasmonic peak downshift of 0.2 eV with respect to the peak position in the LF spectrum. Four pairs of the OA peaks evaluated in the HF spectrum at E p > 2.5 eV reflect splitting of the C60-related lines, suggesting great change in the microscopic conditions with increasing x. Analysis of the film nanostructure and the plasmon-induced conditions allows us to propose a Rashba-like spin splitting effect that suggests valuable sources for spin polarization.

Activation cross section of 63Cu(n,α)60Co reaction

International Nuclear Information System (INIS)

Lu Hanlin; Zhao Wenrong; Yu Weixiang; Yuan Xialin

1990-01-01

The mechanical properties of copper during the irradiation with intensive neutron fluence rate are significant for the safe operation of D-T fusion power reactors. The cross sections measured by activation method show a large discrepancy from 36 to 54 mb in 14 MeV region. The cross sections of 69 Cu(n, α) 60 Co reaction were measured by activation method. Two irradiations were carried out at the Cockcroft-wallon and Van de Graaff accelerators of CIAE using T(d, n) 4 He reaction to produce neutrons. The activities of 24 Na and 60 Co γ-rays for monitor and sample foils were determined absolutely by a calibrated Ge(Li) detector system with an accuracy better than 1%. The present results are compared with the others

Long-term clearance of accidentally inhaled 60Co aerosols in humans

International Nuclear Information System (INIS)

Beleznay, E.; Osvay, M.

1993-03-01

Long-term body retention was measured on six workers inhaling 60 Co aerosols incidentally during manipulation with a high activity 60 Co source. An improved whole body counter technique and calibration provided good conditions to follow the body clearance over 4 years. A two-detector profile scanning arrangement was used to measure the activity distribution 'in vivo' over the lung region. The observed whole body retention followed a two-exponential time function between 10-1500 days. The consistency of the measured retention pattern with ICRP inhalation model was investigated assuming different aerosol size distributions. A possible extension of ICRP lung model is proposed to take into account the actual pulmonary lung clearance determined individually. (R.P.) 29 refs.; 15 figs.; 6 tabs

Preliminary results in advanced head and neck cancer with radiotherapy by multiple fractions a day

International Nuclear Information System (INIS)

Gonzalez, D.G.; Breur, K.; Schueren, E. v.d.

1980-01-01

Nine patients with advanced head and neck cancer were treated by irradiation consisting of three fractions a day of 180 rad administered with intervals of 4 h. The total dose was 4860-5400 rad in an overall time of 11-12 days. The acute mucosal reactions produced by this multifractionated schedule were similar to those observed with conventional fractionation. The acute skin reactions were minimal. The period of acute reactions were shorter than is generally observed with conventional fractionation. In six patients with a follow-up time of six months or longer no late reactions were detected with the exception of one patient requiring permanent tracheostomy because of laryngeal oedema. In the whole group of patients loco-regional control of the disease was achieved. Six patients had maintained the full response for six months or longer. The results so far obtained with this multiple fractions a day schedule are encouraging. More patients have to be entered in this study in order to draw definitive conclusions. (author)

Comparison of clastogen-induced gene expression profiles in wild-type and DNA repair-deficient Rad54/Rad54B cells

Directory of Open Access Journals (Sweden)

van Benthem Jan

2010-01-01

Full Text Available Abstract Background Previously we found that Rad54/Rad54B cells are more sensitive towards mitomycin C (MMC as compared to wild-type (WT cells. This difference in sensitivity was absent upon exposure to other clastogens like bleomycin (BLM and γ-radiation. In order to get further insight into possible underlying mechanisms, gene expression changes in WT and Rad54/Rad54B MEFs (mouse embryonic fibroblasts after exposure to the clastogens MMC and BLM were investigated. Exposures of these cells to mutagens (N-ac-AAF and ENU and vehicle were taken as controls. Results Most exposures resulted in an induction of DNA damage signaling and apoptosis genes and a reduced expression of cell division genes in cells of both genotypes. As expected, responses to N-ac-AAF were very similar in both genotypes. ENU exposure did not lead to significant gene expression changes in cells of both genotypes, presumably due to its short half-life. Gene expression responses to clastogens, however, showed a genotype-dependent effect for BLM and MMC. MMC treated Rad54/Rad54B MEFs showed no induction of p53-signaling, DNA damage response and apoptosis as seen for all the other treatments. Conclusion These data support our finding that different types of clastogens exist and that responses to these types depend on the DNA repair status of the cells.

The accumulation and distribution of 60Co in carp (Cyprinus carpio) in water-fish compartment system

International Nuclear Information System (INIS)

Poppy Intan Tjahaja; Putu Sukmabuana; Eko Susanto

2012-01-01

In relation with nuclear safety assessment, the parameter of radionuclide transfer in the environment is significantly needed for internal doses estimation received by public trough environment - food product - human pathways. International Atomic Energy Agency (IAEA) has published the transfer parameter data for temperate zone in Technical Report Series 472. In order to complete the IAEA data, especially for tropical region, the accumulation and distribution of 60 Co in carp (Cyprinus carpio) was experimentally studied based on the water-fish compartment system. The carp were cultured in 500L water containing 60 Co of about 30 Bq.mL -1 in a water tank. The 60 Co concentration in fish and water were measured using gamma spectrometer. The 60 Co was accumulated and distributed in the fish tissues with the concentration ratio (CR) of 3.08 mL.g -1 1.55 mL.g -1 and 1.14 mL.g -1 for internal organs, bones, and muscle, respectively. The CR of 60 Co in the fish will be useful in internal radiation dose estimation to human trough water-fish-human pathway, and will also complete the IAEA transfer parameter data for tropical region. (author)

Calculation of uncertainties in the protocol of dosimetry for Co 60 beams in Radiotherapy

International Nuclear Information System (INIS)

Velazquez M, S.; Carrera M, F.; Sanchez S, J.

1998-01-01

The objective in this work is to show how the uncertainty is possible to know in the determination of the absorbed dose in Co 60 photon beams and to establish in a rational form, tolerance levels for this. It is took as base the spanish protocol of dosimetry in Radiotherapy. We have been centered in a Co 60 beam. We utilized the statistical theory of little samples. We allowed to suggest a new approach about the treatment of the tolerance levels and the uncertainty of the measurement. After two years of experience in the practical hospitable application we have gotten to put around 1 % uncertainty in the absolute dosimetry of the Co 60 beam. The presented protocol allows to execute the accuracy requirements in the determination of absorbed doses. (Author)

Seed germination of peanuts irradiated with cobalt (60CO)

International Nuclear Information System (INIS)

Alves, Niedja Marrize C.; Almeida, Francisco de Assis C.; Gomes, Josivanda P.; Pessoa, Elvira B.; Leal, Artur S. Cavalcanti

2010-01-01

This work was realized to evaluate the effect of gamma irradiation ( 60 Co) at doses 0, 0.50, 1.00, 1.50, 2.00, 2.50, 3.00 and 4.00 kGy, on germination of seeds of peanut, cultivar BR1. Irradiation Department of Nuclear, UFPE, where he received after the irradiation, they were stored in packing of PET and polyethylene braided with a time of 90 days. Through the results, obtained monthly, concluded that the dose of 0.5 kGy was effective in the germination of seeds of peanut, not affecting its power of germination and overcoming the witness within 30 to 60 days. (author)

Molecular anatomy of the recombination mediator function of Saccharomyces cerevisiae Rad52

DEFF Research Database (Denmark)

Seong, C.; Sehorn, M.G.; Plate, Iben

2008-01-01

A helical filament of Rad51 on single-strand DNA (ssDNA), called the presynaptic filament, catalyzes DNA joint formation during homologous recombination. Rad52 facilitates presynaptic filament assembly, and this recombination mediator activity is thought to rely on the interactions of Rad52...... with Rad51, the ssDNA-binding protein RPA, and ssDNA. The N-terminal region of Rad52, which has DNA binding activity and an oligomeric structure, is thought to be crucial for mediator activity and recombination. Unexpectedly, we find that the C-terminal region of Rad52 also harbors a DNA binding function....... Importantly, the Rad52 C-terminal portion alone can promote Rad51 presynaptic filament assembly. The middle portion of Rad52 associates with DNA-bound RPA and contributes to the recombination mediator activity. Accordingly, expression of a protein species that harbors the middle and C-terminal regions of Rad...

Effects of the rad52 gene on recombination in Saccharomyces cerevisiae

International Nuclear Information System (INIS)

Prakash, S.; Prakash, L.; Burke, W.; Montelone, B.A.

1979-01-01

Effects of the rad52 mutation in Saccharomyces cerevisiae on meiotic, γ-ray-induced, uv-induced, and spontaneous mitotic recombination were studied. The rad52/rad52 diploids undergo premeiotic DNA synthesis; sporulation occurs but inviable spores are produced. Intra- and intergenic recombination during meiosis were examined in cells transferred from sporulation medium to vegetative medium at different time intervals. No intragenic recombination was observed at the hisl-1/hisl-315 and trp5-2/trp5-48 heteroalleles. Gene-centromere recombination was also not observed in rad52/rad52 diploids. No γ-ray-induced intragenic mitotic recombination is seen in rad52/rad52 diploids and uv-induced intragenic recombination is greatly reduced. However, spontaneous mitotic recombination is not similarly affected. The RAD52 gene thus functions in recombination in meiosis and in γ-ray and uv-induced mitotic recombination but not in spontaneous mitotic recombination

HL-60 differentiating activity and flavonoid content of the readily extractable fraction prepared from citrus juices.

Science.gov (United States)

Kawaii, S; Tomono, Y; Katase, E; Ogawa, K; Yano, M

1999-01-01

Citrus plants are rich sources of various bioactive flavonoids. To eliminate masking effects caused by hesperidin, naringin, and neoeriocitrin, the abundant flavonoid glycosides which make up 90% of the conventionally prepared sample, the readily extractable fraction from Citrus juice was prepared by adsorbing on HP-20 resin and eluting with EtOH and acetone from the resin and was subjected to HL-60 differentiation assay and quantitative analysis of major flavonoids. Screening of 34 Citrus juices indicated that King (C. nobilis) had a potent activity for inducing differentiation of HL-60, and the active principles were isolated and identified as four polymethoxylated flavonoids, namely, nobiletin, 3,3',4',5,6,7, 8-heptamethoxyflavone, natsudaidain, and tangeretin. HPLC analysis of the readily extractable fraction also indicated that King contained high amounts of these polymethoxylated flavonoids among the Citrus juices examined. Principal component and cluster analyses of the readily extractable flavonoids indicated peculiarities of King and Bergamot.

Detection and temporal variation of (60)Co in the digestive glands of the common octopus, Octopus vulgaris, in the East China Sea.

Science.gov (United States)

Morita, Takami; Otosaka, Shigeyoshi; Fujimoto, Ken; Nishiuchi, Kou; Kimoto, Katsunori; Yamada, Haruya; Kasai, Hiromi; Minakawa, Masayuki; Yoshida, Katsuhiko

2010-08-01

(60)Co were detected in common octopus specimens collected in the East China Sea in 1996-2005. The source of (60)Co has remained unclear yet. Stable isotope analyses showed that there was no difference in stable Co concentrations between octopus samples with (60)Co and without (60)Co. This result showed that the stable Co in the digestive gland of octopus potentially did not include a trace amount of (60)Co and the source of (60)Co existed independently. Furthermore, investigations of octopus in other area and other species indicated that the origin of the source of (60)Co occurred locally in the restricted area in the East China Sea and not in the coastal area of Japan. Concentrations of (60)Co have annually decreased with shorter half-life than the physical half-life. This decrease tendency suggests that the sources of (60)Co were identical and were temporary dumped into the East China Sea as a solid waste. Copyright 2010 Elsevier Ltd. All rights reserved.

Detection and temporal variation of 60Co in the digestive glands of the common octopus, Octopus vulgaris, in the East China Sea

International Nuclear Information System (INIS)

Morita, Takami; Otosaka, Shigeyoshi; Fujimoto, Ken; Nishiuchi, Kou; Kimoto, Katsunori; Yamada, Haruya; Kasai, Hiromi; Minakawa, Masayuki; Yoshida, Katsuhiko

2010-01-01

60 Co were detected in common octopus specimens collected in the East China Sea in 1996-2005. The source of 60 Co has remained unclear yet. Stable isotope analyses showed that there was no difference in stable Co concentrations between octopus samples with 60 Co and without 60 Co. This result showed that the stable Co in the digestive gland of octopus potentially did not include a trace amount of 60 Co and the source of 60 Co existed independently. Furthermore, investigations of octopus in other area and other species indicated that the origin of the source of 60 Co occurred locally in the restricted area in the East China Sea and not in the coastal area of Japan. Concentrations of 60 Co have annually decreased with shorter half-life than the physical half-life. This decrease tendency suggests that the sources of 60 Co were identical and were temporary dumped into the East China Sea as a solid waste.

Nanoparticles of poly(hydroxybutyrate-co-hydroxyvalerate) as support for the immobilization of Candida antarctica lipase (fraction B)

International Nuclear Information System (INIS)

Fernandes, Ilizandra A.; Nyari, Nadia L.D.; Oliveira, Jose Vladimir de; Oliveira, Debora de; Rigo, Elisandra; Souza, Maria Cristiane M. de; Goncalves, Luciana R.B.; Pergher, Sibele Berenice C.

2014-01-01

This work evaluates the immobilization of Candida antarctica lipase (Fraction B) using poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) nanoparticles as support. The effects of immobilization time (30-150 min) and pH (5-10) on lipase loading were evaluated. The stability of the immobilized enzyme towards temperature (40, 60, and 80 deg C), reuse and storage (at 4 deg C) were also determined. Furthermore, to assess its potential application in a system of interest, the immobilized lipase was used as a catalyst in the esterification of geraniol with oleic acid. The results indicated a time of 120 minutes and pH of 7 as optimal for immobilization. A 21 hour exposure of the PHBV-lipase derivative to 60 deg C showed a 33% reduction of the initial activity while storage at 4 deg C led to a residual activity (5% of the original activity). The derivative was used without significant loss of activity for 4 successive cycles. The use of the immobilized lipase as a catalyst in the production of geranyl oleate led to about 88% conversion of the initial reactants to products. (author)

Early treatment using fractional CO2 laser before skin suture during scar revision surgery in Asians.

Science.gov (United States)

Du, Feiya; Yu, Yusheng; Zhou, Zhiqin; Wang, Liujia; Zheng, Shusen

2018-04-01

Fractional CO 2 laser is one of the most effective treatment options used to resurface scars. However, most previous studies have been performed on mature scars at least 2 months after surgery. Recent studies have emphasized the importance of early treatment to reduce scar formation. In the present study, we described our experience with fractional CO 2 laser intervention before skin suture during scar revision surgery in Asians, and found the treatment was safe and effective.

The role of iron and reactive oxygen species in the production of CO2 in arctic soil waters

Science.gov (United States)

Trusiak, Adrianna; Treibergs, Lija A.; Kling, George W.; Cory, Rose M.

2018-03-01

Hydroxyl radical (radOH) is a highly reactive oxidant of dissolved organic carbon (DOC) in the environment. radOH production in the dark was observed through iron and DOC mediated Fenton reactions in natural environments. Specifically, when dissolved oxygen (O2) was added to low oxygen and anoxic soil waters in arctic Alaska, radOH was produced in proportion to the concentrations of reduced iron (Fe(II)) and DOC. Here we demonstrate that Fe(II) was the main electron donor to O2 to produce radOH. In addition to quantifying radOH production, hydrogen peroxide (H2O2) was detected in soil waters as a likely intermediate in radOH production from oxidation of Fe(II). For the first time in natural systems we detected carbon dioxide (CO2) production from radOH oxidation of DOC. More than half of the arctic soil waters tested showed production of CO2 under conditions conducive for production of radOH. Findings from this study strongly suggest that DOC is the main sink for radOH, and that radOH can oxidize DOC to yield CO2. Thus, this iron-mediated, dark chemical oxidation of DOC may be an important component of the arctic carbon cycle.

Image processing in 60Co container inspection system

International Nuclear Information System (INIS)

Wu Zhifang; Zhou Liye; Wang Liqiang; Liu Ximing

1999-01-01

The authors analyzes the features of 60 Co container inspection image, the design of several special processing methods for container image and some normal processing methods for two-dimensional digital image, including gray enhancement, pseudo-enhancement, space filter, edge enhancement, geometry process, etc. It gives out the way to carry out the above mentioned process in Windows 95 or Win NT. It discusses some ways to improve the image processing speed on microcomputer and good results were obtained

Physical mapping and cloning of RAD56

DEFF Research Database (Denmark)

Mathiasen, David P; Gallina, Irene; Germann, Susanne Manuela

2013-01-01

Here we report the physical mapping of the rad56-1 mutation to the NAT3 gene, which encodes the catalytic subunit of the NatB N-terminal acetyltransferase in Saccharomyces cerevisiae. Mutation of RAD56 causes sensitivity to X-rays, methyl methanesulfonate, zeocin, camptothecin and hydroxyurea...

Re-evaluation of 60Co treatment facility of Korle-Bu Teaching Hospital

International Nuclear Information System (INIS)

Adu, S.

2008-06-01

The radiological protection assessment based on the shielding of the Co-60 Radiotherapy facility at the Korle Bu Teaching Hospital after the source replacement has been carried out. The results indicate that the concrete biological shield is adequate to attenuate the gamma photons from the new 222 TBq Co-60 source in use. The dose rates at critical locations of the public access area are within the recommended dose rate limit of O.5J..1Sv/h and 7.5J..1Sv/h for public and staff respectively. Thus the shielding has not deteriorated and still provides adequate protection for members of the public and the operating staff (au).

Effect of cobalt on the growth of Trichoderma viride and determination of its distribution using 60Co

International Nuclear Information System (INIS)

Frank, V.; Lesny, J.; Babej, L.

1993-01-01

The growth and morphology of filamentous fungus Trichoderma viride grown in the presence of various Co concentrations were studied. Using 60 Co, the cobalt content in mycelium and conidia was determined. No influence of 60 Co-radiation on growth and morphology was observed. (author) 5 refs.; 4 figs

RAD51B in Familial Breast Cancer

DEFF Research Database (Denmark)

Pelttari, Liisa M; Khan, Sofia; Vuorela, Mikko

2016-01-01

Common variation on 14q24.1, close to RAD51B, has been associated with breast cancer: rs999737 and rs2588809 with the risk of female breast cancer and rs1314913 with the risk of male breast cancer. The aim of this study was to investigate the role of RAD51B variants in breast cancer predisposition......, particularly in the context of familial breast cancer in Finland. We sequenced the coding region of RAD51B in 168 Finnish breast cancer patients from the Helsinki region for identification of possible recurrent founder mutations. In addition, we studied the known rs999737, rs2588809, and rs1314913 SNPs and RAD......51B haplotypes in 44,791 breast cancer cases and 43,583 controls from 40 studies participating in the Breast Cancer Association Consortium (BCAC) that were genotyped on a custom chip (iCOGS). We identified one putatively pathogenic missense mutation c.541C>T among the Finnish cancer patients...

Stationary high confinement plasmas with large bootstrap current fraction in JT-60U

International Nuclear Information System (INIS)

Sakamoto, Y.; Fujita, T.; Ide, S.; Isayama, A.; Takechi, M.; Suzuki, T.; Takenaga, H.; Oyama, N.; Kamada, Y.

2005-01-01

This paper reports the results of the progress in stationary discharges with a large bootstrap current fraction in JT-60U towards steady-state tokamak operation. In the weak shear plasma regime, high-β p ELMy H-mode discharges have been optimized under nearly full non-inductive current drive conditions by the large bootstrap current fraction (f BS ∼ 45%) and the beam driven current fraction (f BD ∼ 50%), which was sustained for 5.8 s in the stationary condition. This duration corresponds to ∼26τ E and ∼2.8τ R , which was limited by the pulse length of negative-ion-based neutral beams. The high confinement enhancement factor H 89 ∼ 2.2 (HH 98y2 ∼ 1.0) was obtained and the profiles of current and pressure reached the stationary condition. In the reversed shear plasma regime, a large bootstrap current fraction (f BS ∼ 75%) has been sustained for 7.4 s under nearly full non-inductive current drive conditions. This duration corresponds to ∼16τ E and ∼2.7τ R . The high confinement enhancement factor H 89 ∼ 3.0 (HH 98y2 ∼ 1.7) was also sustained, and the profiles of current and pressure reached the stationary condition. The large bootstrap current and the off-axis beam driven current sustained this reversed q profile. This duration was limited only by the duration of the neutral beam injection

The hyperfractionation in the oropharynx carcinomas treatment: stages III and IV

International Nuclear Information System (INIS)

Pinto, L.H.J.

1990-01-01

From April 1986 until May 1989. 112 patients with stages III and IV oropharynx carcinomas were included in a protocol comparing the use of Hyperfractionation and Conventional Fractionation. The doses were 6600 rad in 33 fractions of 200 rad for the conventional fractionation and 7040 rad in 64 fractions, two fractions of 110 rad per day for the hyperfractionation. As of January 1990 an analysis was performed in 98 patients, with a median follow-up of 14 months. The probability of complete responses in the oropharynx was 74%, with 84% for the hyperfractionation and 64% for the conventional fractionation ( p < 0,05). Survival was improved in 42 months for those patients treated with hyperfractionation: 27% versus 8% (p < 0,05). In patients with lesions out of the base of the tongue and in those with Karnofsky performance status of 50%, 60% and 70%, survival was improved with the use of hyperfractionation (p = 0,02 and p 0,006 respectively. The study demonstrates the superiority of hyperfractionation over the classical fractionation in the treatment of patients with carcinoma of the oropharynx. (author)

Sensory symptom profiles and co-morbidities in painful radiculopathy.

Directory of Open Access Journals (Sweden)

Friederike Mahn

Full Text Available Painful radiculopathies (RAD and classical neuropathic pain syndromes (painful diabetic polyneuropathy, postherpetic neuralgia show differences how the patients express their sensory perceptions. Furthermore, several clinical trials with neuropathic pain medications failed in painful radiculopathy. Epidemiological and clinical data of 2094 patients with painful radiculopathy were collected within a cross sectional survey (painDETECT to describe demographic data and co-morbidities and to detect characteristic sensory abnormalities in patients with RAD and compare them with other neuropathic pain syndromes. Common co-morbidities in neuropathic pain (depression, sleep disturbance, anxiety do not differ considerably between the three conditions. Compared to other neuropathic pain syndromes touch-evoked allodynia and thermal hyperalgesia are relatively uncommon in RAD. One distinct sensory symptom pattern (sensory profile, i.e., severe painful attacks and pressure induced pain in combination with mild spontaneous pain, mild mechanical allodynia and thermal hyperalgesia, was found to be characteristic for RAD. Despite similarities in sensory symptoms there are two important differences between RAD and other neuropathic pain disorders: (1 The paucity of mechanical allodynia and thermal hyperalgesia might be explained by the fact that the site of the nerve lesion in RAD is often located proximal to the dorsal root ganglion. (2 The distinct sensory profile found in RAD might be explained by compression-induced ectopic discharges from a dorsal root and not necessarily by nerve damage. These differences in pathogenesis might explain why medications effective in DPN and PHN failed to demonstrate efficacy in RAD.

Caffeine inhibits gene conversion by displacing Rad51 from ssDNA

Science.gov (United States)

Tsabar, Michael; Mason, Jennifer M.; Chan, Yuen-Ling; Bishop, Douglas K.; Haber, James E.

2015-01-01

Efficient repair of chromosomal double-strand breaks (DSBs) by homologous recombination relies on the formation of a Rad51 recombinase filament that forms on single-stranded DNA (ssDNA) created at DSB ends. This filament facilitates the search for a homologous donor sequence and promotes strand invasion. Recently caffeine treatment has been shown to prevent gene targeting in mammalian cells by increasing non-productive Rad51 interactions between the DSB and random regions of the genome. Here we show that caffeine treatment prevents gene conversion in yeast, independently of its inhibition of the Mec1ATR/Tel1ATM-dependent DNA damage response or caffeine's inhibition of 5′ to 3′ resection of DSB ends. Caffeine treatment results in a dosage-dependent eviction of Rad51 from ssDNA. Gene conversion is impaired even at low concentrations of caffeine, where there is no discernible dismantling of the Rad51 filament. Loss of the Rad51 filament integrity is independent of Srs2's Rad51 filament dismantling activity or Rad51's ATPase activity and does not depend on non-specific Rad51 binding to undamaged double-stranded DNA. Caffeine treatment had similar effects on irradiated HeLa cells, promoting loss of previously assembled Rad51 foci. We conclude that caffeine treatment can disrupt gene conversion by disrupting Rad51 filaments. PMID:26019181

Mongoose: Creation of a Rad-Hard MIPS R3000

Science.gov (United States)

Lincoln, Dan; Smith, Brian

1993-01-01

This paper describes the development of a 32 Bit, full MIPS R3000 code-compatible Rad-Hard CPU, code named Mongoose. Mongoose progressed from contract award, through the design cycle, to operational silicon in 12 months to meet a space mission for NASA. The goal was the creation of a fully static device capable of operation to the maximum Mil-883 derated speed, worst-case post-rad exposure with full operational integrity. This included consideration of features for functional enhancements relating to mission compatibility and removal of commercial practices not supported by Rad-Hard technology. 'Mongoose' developed from an evolution of LSI Logic's MIPS-I embedded processor, LR33000, code named Cobra, to its Rad-Hard 'equivalent', Mongoose. The term 'equivalent' is used to infer that the core of the processor is functionally identical, allowing the same use and optimizations of the MIPS-I Instruction Set software tool suite for compilation, software program trace, etc. This activity was started in September of 1991 under a contract from NASA-Goddard Space Flight Center (GSFC)-Flight Data Systems. The approach affected a teaming of NASA-GSFC for program development, LSI Logic for system and ASIC design coupled with the Rad-Hard process technology, and Harris (GASD) for Rad-Hard microprocessor design expertise. The program culminated with the generation of Rad-Hard Mongoose prototypes one year later.

Oxygen isotope fractionation in the CaCO3-DIC-H2O system

Science.gov (United States)

Devriendt, Laurent S.; Watkins, James M.; McGregor, Helen V.

2017-10-01

The oxygen isotope ratio (δ18O) of inorganic and biogenic carbonates is widely used to reconstruct past environments. However, the oxygen isotope exchange between CaCO3 and H2O rarely reaches equilibrium and kinetic isotope effects (KIE) commonly complicate paleoclimate reconstructions. We present a comprehensive model of kinetic and equilibrium oxygen isotope fractionation between CaCO3 and water (αc/w) that accounts for fractionation between both (a) CaCO3 and the CO32- pool (α c / CO32-) , and (b) CO32- and water (α CO32- / w) , as a function of temperature, pH, salinity, calcite saturation state (Ω), the residence time of the dissolved inorganic carbon (DIC) in solution, and the activity of the enzyme carbonic anhydrase. The model results suggest that: (1) The equilibrium αc/w is only approached in solutions with low Ω (i.e. close to 1) and low ionic strength such as in the cave system of Devils Hole, Nevada. (2) The sensitivity of αc/w to the solution pH and/or the mineral growth rate depends on the level of isotopic equilibration between the CO32- pool and water. When the CO32- pool approaches isotopic equilibrium with water, small negative pH and/or growth rate effects on αc/w of about 1-2‰ occur where these parameters covary with Ω. In contrast, isotopic disequilibrium between CO32- and water leads to strong (>2‰) positive or negative pH and growth rate effects on α CO32-/ w (and αc/w) due to the isotopic imprint of oxygen atoms derived from HCO3-, CO2, H2O and/or OH-. (3) The temperature sensitivity of αc/w originates from the negative effect of temperature on α CO32-/ w and is expected to deviate from the commonly accepted value (-0.22 ± 0.02‰/°C between 0 and 30 °C; Kim and O'Neil, 1997) when the CO32- pool is not in isotopic equilibrium with water. (4) The model suggests that the δ18O of planktic and benthic foraminifers reflects a quantitative precipitation of DIC in isotopic equilibrium with a high-pH calcifying fluid, leading

Pathologic changes in the lung following single and multi-fraction irradiation

International Nuclear Information System (INIS)

Travis, E.L.; Harley, R.A.; Fenn, J.O.; Klobukowski, C.J.; Hargrove, H.B.

1977-01-01

The limiting factor in the treatment of malignant disease with irradiation is the tolerance of normal tissue irradiated. In the present study the right lungs of rats were exposed to single doses of 2000 rad of x-radiation, to 10 x 200 rad, or to 5 x 400 rad. Animals from each group were sacrificed monthly for 6 months post exposure. Sections of lung were examined by light microscopy (LM) and by scanning or transmission electron microscopy (SEM and TEM). A focal exudative lesion was seen at 2 months after the single dose; it progressed to a proliferative and then reparative, fibrotic lesion by 6 months. Changes in epithelial lung components, particularly the presence of Type II pneumocytes, were found with both LM and TM. Vascular changes were less pronounced. A striking finding was the presence of mast cells in the alveolar walls. Neither of the multi-fraction schedules produced any of these changes, except hyperplasia of Type II cells following 5 x 400 rad. The possible implication of Type II and mast cells in radiation pneumonitis and fibrosis is discussed

Biological effect of 60Co γ irradiation on Trichoderma

International Nuclear Information System (INIS)

Chen Jian'ai; Wang Weiming

2003-01-01

The mutagenic effect of 60 Co γ-ray on Trichoderma spp (T 32 ) was studied. The germination capacity of spores apparently declined after irradiation. The mutagenic effect curve model is S=e -λD , and the mutagenic curve is Y=-0.940e 1.29x , r=0.9533(r 0.01 =0.765). 130 variant strain which grew rapidly and produced more spores were chosen

Clinical dosimetry of large shaped 60Co irradiation fields

International Nuclear Information System (INIS)

Novotny, J.

1979-01-01

The determination is described of absorbed doses in the Alderson-Rando phantom by thermoluminescent dosemeters in patients irradiated with irregularly shaped large-surface fields of Co 60 . In a range of 3 to 5% the measured values correspond to the values calculated with the aid of relations presented by Bukowitz. Non-homogeneity of irradiation when two supradiaphragmatic fields are used and its improvement are discussed. (author)

A dedicated BI-RADS training programme: Effect on the inter-observer variation among screening radiologists

International Nuclear Information System (INIS)

Timmers, J.M.H.; Doorne-Nagtegaal, H.J. van; Verbeek, A.L.M.; Heeten, G.J. den; Broeders, M.J.M.

2012-01-01

Introduction: The Breast Imaging Reporting and Data System (BI-RADS) was introduced in the Dutch breast cancer screening programme to improve communication between medical specialists. Following introduction, a substantial variation in the use of the BI-RADS lexicon for final assessment categories was noted among screening radiologists. We set up a dedicated training programme to reduce this variation. This study evaluates whether this programme was effective. Materials and methods: Two comparable test sets were read before and after completion of the training programme. Each set contained 30 screening mammograms of referred women selected from screening practice. The sets were read by 25 experienced and 30 new screening radiologists. Cohen's kappa (κ) was used to calculate the inter-observer agreement. The BI-RADS 2003 version was implemented in the screening programme as the BI-RADS 2008 version requires the availability of diagnostic work-up, and this is unavailable. Results: The inter-observer agreement of all participating radiologists (n = 55) with the expert panel increased from a pre-training κ-value of 0.44 to a post-training κ-value of 0.48 (p = 0.14). The inter-observer agreement of the new screening radiologists (n = 30) with the expert panel increased from κ = 0.41 to κ = 0.50 (p = 0.01), whereas there was no difference in agreement among the 25 experienced radiologists (from κ = 0.48 to κ = 0.46, p = 0.60). Conclusion: Our training programme in the BI-RADS lexicon resulted in a significant improvement of agreement among new screening radiologists. Overall, the agreement among radiologists was moderate (guidelines Landis and Koch). This is in line with results found in the literature

60Co accumulation from sediment and planktonic algae by midge larvae (Chironomus luridus)

International Nuclear Information System (INIS)

Baudin, J.P.; Nucho, R.

1992-01-01

This paper reports the results of several experiments carried out to evaluate uptake and retention by a limicolous midge larva of 60 Co retained in sediment, either adsorbed on mineral particles or bound to planktonic algae. In order to determine their relative contributions in radionuclide accumulation, the different vectors (water, algae and sediment) were first labelled individually and then simultaneously. 60 Co accumulation from water and from algae results in a maximum concentration factor of 30 and in a mean trophic transfer factor of 4·5 × 10 −3 . The level of contamination of midge larvae from sediment is markedly influenced by the presence of endogenous organic matter. Thus the radionuclide transfer factor is about twice as high for larvae placed in labelled raw sediment than for larvae placed in labelled incinerated sediment, in the presence as in the absence of contaminated planktonic algae. Irrespective of the contamination conditions, 60 Co depuration from midge larvae is a very rapid phenomenon that corresponds, in all cases, to a radionuclide half-life of only a few days

60Co accumulation from sediment and planktonic algae by midge larvae (Chironomus luridus)

International Nuclear Information System (INIS)

Baudin, J.P.; Nucho, R.

1992-01-01

This paper reports the results of several experiments carried out to evaluate uptake and retention by a limicolous midge larva of 60 Co retained in sediment, either adsorbed on mineral particles or bound to planktonic algae. In order to determine their relative contributions in radionuclide accumulation, the different vectors (water, algae and sediment) were first labelled individually and then simultaneously. 60 Co accumulation from water and from algae results in a maximum concentration factor of 30 and in a mean trophic transfer factor of 4.5 x 10 -3 . The level of contamination of midge larvae from sediment is markedly influenced by the presence of endogenous organic matter. Thus the radionuclide transfer factor is about twice as high for larvae placed in labelled raw sediment than for larvae placed in labelled incinerated sediment, in the presence as in the absence of contaminated planktonic algae. Irrespective of the contamination conditions, 60 Co depuration from midge larvae is a very rapid phenomenon that corresponds, in all cases, to a radionuclide half-life of only a few days. (author)

Effects of 60Co γ-radiation on brain hippocampal tissue of adult mice

International Nuclear Information System (INIS)

Liu Yongbao; Rao Yongqing; Xu Luxi

2000-01-01

Objective: To study neuro-pathological changes of hippocampus tissue in adult mice following a series of irradiation with 60 Co γ-rays. Methods: Male mice of Kunming strain in experimental group (n = 8) were exposed total-bodily to 60 Co γ-rays at 2.0 Gy once every two days. A histopathological imaging analysis of the mouse brain tissue was carried out after paraffin embedding and a series of sections were made and stained with Nissl and Weil staining methods. Results: In the irradiation group (the cumulative dose = 26 Gy) loss of pyramidal cells in hippocampus was significant when compared with the control group. Neuro-pathological changes were characterised by reduced neuron size, nuclear pyknosis and karyolysis. The neurofibrillar density of the pyramidal layer in the irradiation group was much lower than that of the control group (P CA2>CA3>CA4 in the hippocampus. Conclusion: The neuronal damage in hippocampus after 60 Co irradiation could form a pathological basis in reduction of memorial and learning ability

Effect of 60Co-γ ray irradiation on green coffee beans, 1

International Nuclear Information System (INIS)

Tomoda, Goro; Matsuyama, Jun; Hiramoto, Keiko; Izu, Kumie

1977-01-01

Green coffee beans were irradiated with 60 Co-γ rays at doses of 0, 0.05, 0.5, 5.0 and 10.0 Mrad and the changes of general components in green and roast coffee beans were investigated together with those of the organoleptic properties of roast beans during storage according to the cup testing. In case of Brazil santos beans, irradiation of some 0.05 Mrad 60 Co-γ ray gave rather favourable mild flavour and no harmful influence on the quality of coffee, and moreover, would tend to extend the shelf life of roast beans. But influence of irradiation on the quality of coffee differed somewhat between two cultivars, Brazil santos and Colombia. (auth.)

Screening of strains with the high activity and thermostability nattokinase by {sup 60}Co γ-ray irradiation

Energy Technology Data Exchange (ETDEWEB)

Shuying, Li; Ying, Nie; Huan, Du; Xuanming, Tang [Institute of Agro-products Processing Science and Technology, Chinese Academy of Agricultural Sciences, Beijing (China); Zhonglin, Zhao [College of Sciences, Henan Agricultural University, Zhengzhou (China); Xin, Ma [Agricultural Information Institute, Chinese Academic of Agricultural Sciences, Beijing (China); Yan, Li [School of Food and Biological Engineering, Zhengzhou University of Light Industry, Zhengzhou (China)

2013-06-15

In this study, Bacillus natto was irradiated by {sup 60}Co γ-ray, and activity was determined by Casein plate method in order to get high activity and thermostability strains. 60 strains with high activity were obtained through irradiation by 800 Gy {sup 60}Co γ-ray. In this dose, the positive mutation rate was 45%. Then 60 strains was treated by different tempreture and 11 strains showed thermostability at 65℃. (authors)

Screening of strains with the high activity and thermostability nattokinase by "6"0Co γ-ray irradiation

International Nuclear Information System (INIS)

Li Shuying; Nie Ying; Du Huan; Tang Xuanming; Zhao Zhonglin; Ma Xin; Li Yan

2013-01-01

In this study, Bacillus natto was irradiated by "6"0Co γ-ray, and activity was determined by Casein plate method in order to get high activity and thermostability strains. 60 strains with high activity were obtained through irradiation by 800 Gy "6"0Co γ-ray. In this dose, the positive mutation rate was 45%. Then 60 strains was treated by different tempreture and 11 strains showed thermostability at 65℃. (authors)

Effect of 60Co γ-rays on polyphenyl methacrylate obtained by γ-ray irradiation

International Nuclear Information System (INIS)

Raghunath, S.; Rao, M.H.; Rao, K.N.

1983-01-01

Polyphenyl methacrylate of different molecular weights Msub(n) 13000, 34500 and crosslinked polymer prepared by 60 Co γ-irradiation has been irradiated with 60 Co γ-rays at 300 K. G(scission) of the 13000 molecular weight polymer was 15. The crosslinked polymer undergoes both degradation and crosslinking. G(x) value determined for that polymer is approx. 9. The gaseous product consists largely of CO with some CO 2 and H 2 . Hydrocarbon gases were not detected. The yield of H 2 is only to the extent of 2 to 5% of the total gas and it is assumed that majority of scission takes place at the ester linkage. On the basis of the estimation of phenol and benzene, a mechanism for degradation and crosslinking is proposed. (author)

RadNet Air Data From Fort Smith, AR

Science.gov (United States)

This page presents radiation air monitoring and air filter analysis data for Fort Smith, AR from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

RadNet Air Data From Little Rock, AR

Science.gov (United States)

This page presents radiation air monitoring and air filter analysis data for Little Rock, AR from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

RadNet Air Data From Mason City, IA

Science.gov (United States)

This page presents radiation air monitoring and air filter analysis data for Mason City, IA from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

Development and evaluation of a technique for in vivo monitoring of 60Co in the lungs

International Nuclear Information System (INIS)

Mello, J.Q. de; Lucena, E.A.; Dantas, A.L.A.; Dantas, B.M.

2015-01-01

60 Co is a fission product of 235 U and represents a risk of internal exposure of workers in nuclear power plants, especially those involved in the maintenance of potentially contaminated parts and equipment. The control of 60 Co intake by inhalation can be performed through in vivo monitoring. This work describes the evaluation of a technique through the minimum detectable activity and the corresponding minimum detectable effective doses, based on biokinetic and dosimetric models of 60 Co in the human body. The results allow to state that the technique is suitable either for monitoring of occupational exposures or evaluation of accidental intakes. (author)

Reach Address Database (RAD)

Data.gov (United States)

U.S. Environmental Protection Agency — The Reach Address Database (RAD) stores the reach address of each Water Program feature that has been linked to the underlying surface water features (streams,...

The effects of atmospheric [CO2] on carbon isotope fractionation and magnesium incorporation into biogenic marine calcite

Science.gov (United States)

Vieira, Veronica

1997-01-01

The influences of atmospheric carbon dioxide on the fractionation of carbon isotopes and the magnesium incorporation into biogenic marine calcite were investigated using samples of the calcareous alga Amphiroa and benthic foraminifer Sorites grown in the Biosphere 2 Ocean system under variable atmospheric CO2 concentrations (approximately 500 to 1200 ppm). Carbon isotope fractionation was studied in both the organic matter and the skeletal carbonate. Magnesium analysis was to be performed on the carbonate removed during decalcification. These data have not been collected due to technical problems. Carbon isotope data from Amphiroa yields a linear relation between [CO2] and Delta(sup 13)C(sub Corg)values suggesting that the fractionation of carbon isotopes during photosynthesis is positively correlated with atmospheric [CO2]. [CO2] and Delta(sup 13)C(sub Corg) values for Sorites produce a relation that is best described by a hyperbolic function where Delta(sup 13)C(sub Corg) values increase between 300 and 700 ppm and decrease from 700 to 1200 ppm. Further investigation of this relation and Sorites physiology is needed.

Change of cell cycle arrest of tumor cell lines after 60Co γ-irradiation

International Nuclear Information System (INIS)

Tang Yi; Liu Wenli; Zhou Jianfeng; Gao Qinglei; Wu Jianhong

2003-01-01

Objective: To observe the cell cycle arrest changes in peripheral blood mononuclear cells (PBMNCs) of normal persons and several kinds of tumor cell lines after 60 Co γ-irradiation. Methods: PBMNCs of normal persons, HL-60, K562, SiHA and 113 tumor cell lines were irradiated with 60 Co γ-rays at the absorbed doses of 6, 10,15 Gy. Cell cycles changes were checked 6, 12, 24, 48 and 60 h after the irradiation. Results: A stasis state was observed in normal person PBMNCs, 95 percents of which were in G 1 phase, and they still remained stasis after the irradiation. Except the 113 cell line manifesting G 1 phase arrest, all other tumor cell lines showed G 2 /M phase arrest after irradiation. The radiation sensitivity of HL-60 was higher than that of SiHA cell line. Conclusion: Different cell lines have different cell cycle arrest reaction to radiation and their radiation sensitivity are also different

Germline RAD51B truncating mutation in a family with cutaneous melanoma

DEFF Research Database (Denmark)

Wadt, Karin A W; Aoude, Lauren G; Golmard, Lisa

2015-01-01

Known melanoma predisposition genes only account for around 40% of high-density melanoma families. Other rare mutations are likely to play a role in melanoma predisposition. RAD51B plays an important role in DNA repair through homologous recombination, and inactivation of RAD51B has been implicated...... in tumorigenesis. Thus RAD51B is a good candidate melanoma susceptibility gene, and previously, a germline splicing mutation in RAD51B has been identified in a family with early-onset breast cancer. In order to find genetic variants associated with melanoma predisposition, whole-exome sequencing was carried out...... on blood samples from a three-case cutaneous melanoma family. We identified a novel germline RAD51B nonsense mutation, and we demonstrate reduced expression of RAD51B in melanoma cells indicating inactivation of RAD51B. This is only the second report of a germline truncating RAD51B mutation. While...

Radiological information management system (RadIMS)

International Nuclear Information System (INIS)

Oesterling, R.G.; Marko, S.A.; Tschaeche, A.N.

1991-01-01

Westinghouse Idaho Nuclear Company, Inc. (WINCO) is developing and implementing an information management system, known as RadIMS, to track and record personnel exposure to ionizing radiation. RadIMS has been designed to fulfill all the requirements of US Department of Energy (USDOE) Order 5480.11, ''Radiation Protection for Occupational Workers.'' This Order requires the contractor to maintain detailed radiation exposure records on all individuals who work at the facility. These records must be retrievable for the entire working life of the individual and be available to other USDOE contractors on request. To meet these general needs, RadIMS provides for retrieval of detailed, comprehensive individual exposure histories as well as the usual online interactions to accomplish day-today radiation protection operations. These two extremes of functionality require different approaches in the WINCO computing environment. The exposure histories include database text, paper, microfilm, and electronic bitmaps

Radiological information management system (RadIMS)

Energy Technology Data Exchange (ETDEWEB)

Oesterling, R.G.; Marko, S.A.; Tschaeche, A.N.

1991-08-19

Westinghouse Idaho Nuclear Company, Inc. (WINCO) is developing and implementing an information management system, known as RadIMS, to track and record personnel exposure to ionizing radiation. RadIMS has been designed to fulfill all the requirements of US Department of Energy (USDOE) Order 5480.11, Radiation Protection for Occupational Workers.'' This Order requires the contractor to maintain detailed radiation exposure records on all individuals who work at the facility. These records must be retrievable for the entire working life of the individual and be available to other USDOE contractors on request. To meet these general needs, RadIMS provides for retrieval of detailed, comprehensive individual exposure histories as well as the usual online interactions to accomplish day-today radiation protection operations. These two extremes of functionality require different approaches in the WINCO computing environment. The exposure histories include database text, paper, microfilm, and electronic bitmaps.

Radiological information management system (RadIMS)

Energy Technology Data Exchange (ETDEWEB)

Oesterling, R.G.; Marko, S.A.; Tschaeche, A.N.

1991-08-19

Westinghouse Idaho Nuclear Company, Inc. (WINCO) is developing and implementing an information management system, known as RadIMS, to track and record personnel exposure to ionizing radiation. RadIMS has been designed to fulfill all the requirements of US Department of Energy (USDOE) Order 5480.11, ``Radiation Protection for Occupational Workers.`` This Order requires the contractor to maintain detailed radiation exposure records on all individuals who work at the facility. These records must be retrievable for the entire working life of the individual and be available to other USDOE contractors on request. To meet these general needs, RadIMS provides for retrieval of detailed, comprehensive individual exposure histories as well as the usual online interactions to accomplish day-today radiation protection operations. These two extremes of functionality require different approaches in the WINCO computing environment. The exposure histories include database text, paper, microfilm, and electronic bitmaps.

RadNet Radiological Air Monitoring Network

International Nuclear Information System (INIS)

Scott Telofski, J.; Askren, D.R.; Petko, Ch.M.; Fraass, R.G.

2010-01-01

The United States Environmental Protection Agency operates a national environmental radiation monitoring program called RadNet. RadNet monitors airborne particulates, precipitation, milk, and drinking water for radiation levels. The primary purpose of the original program in the 1950's and 1960's was to collect and analyze samples in various media to assess the effects of radioactive fallout from above-ground nuclear weapon testing. As above-ground testing diminished in the 1970's, the program, especially the air network, became critical in evaluating effects of other types of nuclear incidents, such as the nuclear reactor accident at Chernobyl, as well as monitoring trends in environmental radioactive contamination. The value of rapid data collection subsequent to such incidents led to the consideration of developing air monitors with radiation detectors and telecommunication equipment for real-time radiation measurement. The strengthened United States homeland security posture after 2001 led to production and installation of the current real-time RadNet air monitors. There are now 118 stationary, continuously operating air monitoring stations and 40 mobile air monitors for site specific monitoring. The stationary air monitors include radiation detectors, meteorological sensors, a high-volume air sampler, and communication devices for hourly data transfers. When unusual levels are detected, scientists download a full sodium iodide detector spectrum for analysis. The real-time data collected by RadNet stationary systems permit rapid identification and quantification of airborne nuclides with sufficient sensitivity to provide critical information to help determine protective actions. The data also may help to rapidly refine long-range radioactive plume models and estimate exposure to the population. This paper provides an overview of the airborne particulate monitoring conducted during above-ground nuclear weapon testing, summarizes the uses of data from the program

Chemical grafting of Co9S8 onto C60 for hydrogen spillover and storage.

Science.gov (United States)

Han, Lu; Qin, Wei; Zhou, Jia; Jian, Jiahuang; Lu, Songtao; Wu, Xiaohong; Fan, Guohua; Gao, Peng; Liu, Boyu

2017-04-20

Metal modified C 60 is considered to be a potential hydrogen storage medium due to its high theoretical capacity. Research interest is growing in various hybrid inorganic compounds-C 60 . While the design and synthesis of a novel hybrid inorganic compound-C 60 is difficult to attain, it has been theorized that the atomic hydrogen could transfer from the inorganic compound to the adjacent C 60 surfaces via spillover and surface diffusion. Here, as a proof of concept experiment, we graft Co 9 S 8 onto C 60 via a facile high energy ball milling process. The Raman, XPS, XRD, TEM, HTEM and EELS measurements have been conducted to evaluate the composition and structure of the pizza-like hybrid material. In addition, the electrochemical measurements and calculated results demonstrate that the chemical "bridges" (C-S bonds) between these two materials enhance the binding strength and, hence, facilitate the hydriding reaction of C 60 during the hydrogen storage process. As a result, an increased hydrogen storage capacity of 4.03 wt% is achieved, along with a favorable cycling stability of ∼80% after 50 cycles. Excluding the direct hydrogen storage contribution from Co 9 S 8 in the hybrid paper, the hydrogen storage ability of C 60 was enhanced by 5.9× through the hydriding reaction caused by the Co 9 S 8 modifier. Based on these experimental measurements and theoretical calculations, the unique chemical structure reported here could potentially inspire other C 60 -based advanced hybrids.

The mutant strain of ZHJ6 degrading organophosphorous pesticide by 60Co-γ irradiation

International Nuclear Information System (INIS)

Zhao Renbang; Chi Jian; He Yi

2013-01-01

The strain of Penicillium oxalicum ZHJ6 that can degrade methamidophos was employed to obtain the mutant stain which has higher degradation rate than original strain by 60 Co-γ irradiation. Results showed that the Penicillium oxalicum ZHJ6 was sensitive to 60 Co-γ irradiation, and was easy to be killed by 60 Co-γ irradiation. Under the absorbed dose of 2.1 kGy, the survival rate of the strain was 0.04%. Two strains of A17 and A18 were obtained from the irradiated strains after first- and second- screening and the degradation rate of methamidophos of A17 and A18 strains were 10% higher than that of A0 strain (original stain). Moreover, the abilities to degrade folimat, phoxim and glyphosate were improved. Through 5 generations, the variation coefficient in degradation rate of methamidophos in the 6th day was 1.2%, showing that the new strains had hereditary stability. (authors)

The measurement of carboxyhemoglobin and methemoglobin using a non-invasive pulse CO-oximeter.

Science.gov (United States)

Zaouter, Cédrick; Zavorsky, Gerald S

2012-07-01

The pulse CO-oximeter (Rad-57 Masimo Corporation, Irvine, CA) allows non-invasive and instantaneous measurement of carboxyhemoglobin (COHb) and methemoglobin (MetHb) percentage level using a finger probe. However, the accuracy and reliability of the Rad-57 against the gold standard of venous or arterial blood samples have not been clearly established. Thus, the objective of this trial is to evaluate the accuracy and precision of the Rad-57 pulse CO-oximeter by comparing it with venous sampling on the same subjects. Nine healthy subjects were subjected to carbon monoxide such that it raised the COHb to 10-14% on two different days and pooled together. The COHb and MetHb were measured with a blood gas-analyzer and simultaneously with the Rad-57 as the COHb increased from 1.4 to 14%. Results were compared using linear regression and a Bland and Altman method comparison. Mean bias and precision for COHb measured with the Rad-57 was -1% and 2.5%, respectively. The mean bias and precision for MetHb measured with the Rad-57 was 0.0% and 0.3%, respectively. The ability to detect a COHb ≥ 10% occurred in 54% of the samples in which COHb was ≥ 10-14%. In conclusion, the Rad-57 provides a reading that is between -6% and +4% of the true COHb value for 95% of all samples. The Rad-57 seems to be a good substitute as a first screening test of COHb when the pulse CO-oximeter reads <15%. Copyright © 2012 Elsevier B.V. All rights reserved.

Human RAD50 makes a functional DNA-binding complex.

Science.gov (United States)

Kinoshita, Eri; van Rossum-Fikkert, Sari; Sanchez, Humberto; Kertokalio, Aryandi; Wyman, Claire

2015-06-01

The MRE11-RAD50-NBS1 (MRN) complex has several distinct functions in DNA repair including important roles in both non-homologous end-joining (NHEJ) and homologous recombination (HR). The biochemical activities of MR(N) have been well characterized implying specific functional roles for the components. The arrangement of proteins in the complex implies interdependence of their biochemical activities making it difficult to separate specific functions. We obtained purified human RAD50 and observed that it binds ATP, undergoes ATP-dependent conformational changes as well as having ATPase activity. Scanning force microscopy analysis clearly showed that RAD50 binds DNA although not as oligomers. RAD50 alone was not functional in tethering DNA molecules. ATP increased formation of RAD50 multimers which were however globular lacking extended coiled coils, in contrast to the MR complex where ATP induced oligomers have obvious coiled coils protruding from a central domain. These results suggest that MRE11 is important in maintaining the structural arrangement of RAD50 in the protein complex and perhaps has a role in reinforcing proper alignment of the coiled coils in the ATP-bound state. Copyright © 2015 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

R1800: a new Co 60 sealed source

International Nuclear Information System (INIS)

Freijo, Jose L.; Gomez, Gonzalo

2005-01-01

The increasing demand of Co 60 sealed sources in the international market has made necessary the development of new models of sealed sources. R 1800 type source up to 65 KCi has a design that allows to accommodate a wide spectrum of capsules with different specific activities. The company Dioxitek has developed the fabrication process and the design specifications needed to obtain the approval of the product. A first shipment of 100 KCi has been made with success to the United Kingdom in October of the current year. (author) [es