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Sample records for split dose repair

  1. Effects of cytotoxic chemotherapeutic agents on split-dose repair in intestinal crypt cells

    International Nuclear Information System (INIS)

    Phillips, Theodore L.; Ross, Glenda Y.

    1997-01-01

    Purpose: Many cancer chemotherapeutic agents interact with radiation to enhance the amount of radiation damage observed in both tumor and normal tissues. It is important to predict this interaction and to determine the effect of drug on sublethal damage repair. To evaluate for effects in rapid renewing normal tissues, the intestinal crypt cell in vivo assay is an excellent one to employ. These studies investigate the effect of eleven cancer chemotherapeutic drugs on split-dose repair in the intestinal crypt cell of the mouse. Methods and Materials: LAF1 male mice, age 10-12 weeks, were exposed to whole-body irradiation with orthovoltage x-rays delivered as a single dose or as equally divided doses delivered with intervals between the two exposures of 2 to 24 h. In the experimental group, the cancer chemotherapeutic agent was administered intraperitoneally 2 h before the first radiation dose. At 3.6 days after the second irradiation, the mice were sacrificed; the jejunum was removed, fixed, and sectioned for light microscopy. The number of regenerating crypts were counted and corrected to represent the number of surviving cells per circumference. Results: Of the eleven drugs tested, only carmustine eliminated split-dose repair. Cisplatin delayed repair, and methotrexate caused marked synchronization obliterating the observation of split-dose repair. Conclusions: Most cytotoxic chemotherapeutic agents do not inhibit sublethal damage repair in intestinal crypt cells when given 2 h before the first radiation exposure. Absence of the initial increase in survival seen with split-dose radiation is noted with carmustine and high-dose methotrexate

  2. Characteristics of repair following very low doses

    International Nuclear Information System (INIS)

    Braby, L.A.; Metting, N.F.; Nelson, J.M.

    1987-01-01

    The effects of ionizing radiation on living systems being with the physical processes of energy deposition and develop through many stages of chemical reaction and biological response. The modeling effort attempts to organize the available data and theories of all of these stages into self-consistent models that can be compared and tested. In some cases, important differences among models result in only small differences in cell survival within the ranges of dose and dose rate that are normally investigated. To overcome this limitation, new ways of irradiating cells at extremes of dose rate, or ways of evaluating the effects of very small doses, are developed. Mathematical modeling and cellular studies complement each other. It has recently been found that some mechanisms are not adequate to account for the interaction of dose and repair time as they affect the reproductive survival of plateau-phase Chinese hamster ovary (CHO) cells. Repair of radiation-induced cellular damage plays a central role in the survival of cells exposed to doses of 1 Gy or more. This repair is responsible for the dose rate, split-dose and delayed plating effect and can be evaluated. Because split-dose and dose-rate experiments involve repair during irradiation and delayed plating experiments involve repair after irradiation is completed, it was originally thought that different repair processes were involved. It is now clear that this is not necessarily the case. Appropriately designed models can account for observed effects at conventional doses (1 Gy or more) whether they assume all damage is lethal unless repaired or some damage is innocuous unless it interacts with additional damage. The fact that the survival following a plating delay is always less than the survival following immediate plating at low doses indicates that the damage produced is probably not potentially lethal

  3. Repair of sublethal damage in mammalian cells irradiated at ultrahigh dose rates

    International Nuclear Information System (INIS)

    Gerweck, L.E.; Epp, E.R.; Michaels, H.B.; Ling, C.C.; Peterson, E.C.

    1979-01-01

    The lethal response of asynchronous Chinese hamster ovary (CHO) cells exposed to single and split doses of radiation at conventional or ultrahigh dose rates has been examined to determine whether repair of sublethal damage occurs in cells irradiated at ultrahigh dose rates. The high-intensity irradiations were performed with electrons delivered in single 3-nsec pulses from a 600-kV field emission source under medium-removed, thin-layer conditions. Conventional dose-rate experiments were done under identical thin-layer conditions with 50-kVp x rays, or under full-medium conditions with 280-kVp x rays. Oxygenated cells were irradiated and maintained at 22 to 24 0 C between exposures. Survival did not increase as the time between two doses of pulsed electrons increased from 0 to 4 min, indicating no evidence of fast repair. However, increased survival was observed when 30 to 90 min was allowed to elapse between the split doses. The half-time for maximum repair was approx. = 30 min irrespective of the exposure conditions and radiation modality used. Observed repair ratios increased from approx. = 2 to 4 as the single-dose surviving fraction decreased from 10 -2 to 5 x 10 -4 . Over this survival range the repair ratios, measured at the same value of surviving fraction, were independent of dose rate. The observed repair ratios imply that the shoulder regions of the nonfractionated x-ray and pulsed-electron survival curves were not completely restored between the split doses. However, the fraction of the shoulder restored between split doses of radiation was dose-rate-independent. It is concluded that sublethal damage can be repaired in oxygenated CHO cells irradiated at dose rates of the order of 10 11 rad/sec

  4. The influence of dose per fraction on repair kinetics

    International Nuclear Information System (INIS)

    Rojas, A.; Joiner, M.C.

    1989-01-01

    The use of multiple fractions per day (MFD) in radiotherapy requires information about the rate of repair of radiation injury. It is important to know the minimum interval between fractions necessary for maximum sparing of normal tissue damage, whether rate of repair is dependent on the size of dose per fraction and if it is different in early and late responding tissues and in tumours. To address these questions, the rate of repair between radiation dose fractions was measured in mouse skin (acute damage), mouse kidney (late damage) and a mouse tumour (carcinoma NT). Skin and kidney measurements were made using multiple split doses of X-rays, followed by a neutron top-up. For skin, faster recovery was obtained with 4.4 Gy fractions (t1/2 = 3.46 ± 0.88 h). In contrast kidney showed slower recovery at a low dose per fraction of 2 Gy (t1/2 = 1.69 ± 0.39 h) than at a higher dose of 7 Gy per fraction (t1/2 = 0.92 ± 0.1h). These data show that repair rate is dependent on the size of dose per fraction, but not in a simple way. T1/2 values now available for many different tissues generally lie in the range of 1-2h, and are not correlated with proliferation status or early versus late response to treatment. At the doses used currently in clinical MFD treatments, these data indicate that damage in almost all normal tissues would increase if interfraction intervals less than 6 h were used. The t1/2 for CaNT (0.31 ± 0.15 h) is less than for any normal tissue. This underlines that the excess morbidity resulting from interfraction intervals < 6 h will not be paralleled by an increased effect in tumours. (author). 25 refs.; 7 figs

  5. Repair and dose-response at low doses

    International Nuclear Information System (INIS)

    Totter, J.R.; Weinberg, A.M.

    1977-04-01

    The DNA of each individual is subject to formation of some 2-4 x 10 14 ion pairs during the first 30 years of life from background radiation. If a single hit is sufficient to cause cancer, as is implicit in the linear, no-threshold theories, it is unclear why all individuals do not succumb to cancer, unless repair mechanisms operate to remove the damage. We describe a simple model in which the exposed population displays a distribution of repair thresholds. The dose-response at low dose is shown to depend on the shape of the threshold distribution at low thresholds. If the probability of zero threshold is zero, the response at low dose is quadratic. The model is used to resolve a longstanding discrepancy between observed incidence of leukemia at Nagasaki and the predictions of the usual linear hypothesis

  6. Mechanistic formulation of a lineal-quadratic-linear (LQL) model: Split-dose experiments and exponentially decaying sources

    International Nuclear Information System (INIS)

    Guerrero, Mariana; Carlone, Marco

    2010-01-01

    Purpose: In recent years, several models were proposed that modify the standard linear-quadratic (LQ) model to make the predicted survival curve linear at high doses. Most of these models are purely phenomenological and can only be applied in the particular case of acute doses per fraction. The authors consider a mechanistic formulation of a linear-quadratic-linear (LQL) model in the case of split-dose experiments and exponentially decaying sources. This model provides a comprehensive description of radiation response for arbitrary dose rate and fractionation with only one additional parameter. Methods: The authors use a compartmental formulation of the LQL model from the literature. They analytically solve the model's differential equations for the case of a split-dose experiment and for an exponentially decaying source. They compare the solutions of the survival fraction with the standard LQ equations and with the lethal-potentially lethal (LPL) model. Results: In the case of the split-dose experiment, the LQL model predicts a recovery ratio as a function of dose per fraction that deviates from the square law of the standard LQ. The survival fraction as a function of time between fractions follows a similar exponential law as the LQ but adds a multiplicative factor to the LQ parameter β. The LQL solution for the split-dose experiment is very close to the LPL prediction. For the decaying source, the differences between the LQL and the LQ solutions are negligible when the half-life of the source is much larger than the characteristic repair time, which is the clinically relevant case. Conclusions: The compartmental formulation of the LQL model can be used for arbitrary dose rates and provides a comprehensive description of dose response. When the survival fraction for acute doses is linear for high dose, a deviation of the square law formula of the recovery ratio for split doses is also predicted.

  7. Split high-dose oral levothyroxine treatment as a successful therapy option in myxedema coma.

    Science.gov (United States)

    Charoensri, Suranut; Sriphrapradang, Chutintorn; Nimitphong, Hataikarn

    2017-10-01

    High-dose intravenous thyroxine (T4) is the preferable treatment for myxedema coma. We describe the clinical course of a 69-year-old man who presented with myxedema coma and received oral levothyroxine (LT4) therapy (1 mg) in a split dose. This suggests split high-dose oral LT4 as a therapeutic option in myxedema coma.

  8. Split dose recovery studies using homologous recombination deficient gene knockout chicken B lymphocyte cells

    International Nuclear Information System (INIS)

    Rao, B.S.S.; Tano, Kaori; Utsumi, Hiroshi; Takeda, Shunichi

    2007-01-01

    To understand the role of proteins involved in double strand breaks (DSB) repair modulating sublethal damage (SLD) recovery, chicken B lymphoma (DT 40) cell lines either proficient or deficient in RAD52, XRCC2, XRCC3, RAD51C and RAD51D were subjected to fractionated irradiation and their survival curves charted. Survival curves of both WT DT40 and RAD52 -/- cells had a big shoulder while all the other cells exhibited small shoulders. However, at the higher doses of radiation, RAD51C -/- cells displayed hypersensitivity comparable to the data obtained for the homologous recombination deficient RAD54 -/- cells. Repair of SLD was measured as an increase in survival after a split dose irradiation with an interval of incubation between the radiation doses. All the cell lines (parental DT40 and genetic knockout cell lines viz., RAD52 -/- , XRCC2 -/- XRCC3 -/- RAD51C -/- and RAD51D -/- ) used in this study demonstrated a typical split-dose recovery capacity with a specific peak, which varied depending on the cell type. The maximum survival of WT DT40 and RAD52 -/- was reached at about 1-2 hours after the first dose of radiation and then decreased to a minimum thereafter (5 h). The increase in the survival peaked once again by about 8 hours. The survival trends observed in XRCC2 -/- , XRCC3 -/- , RAD51C -/- and RAD51D -/- knockout cells were also similar, except for the difference in the initial delay of a peak survival for RAD51D -/- and lower survival ratios. The second phase of increase in the survival in these cell lines was much slower in XRCC2 -/- , XRCC3 -/- , RAD51C -/- nd RAD51D -/- and further delayed when compared with that of RAD52 -/- and parental DT40 cells suggesting a dependence on their cell cycle kinetics. This study demonstrates that the participation of RAD52, XRCC2, XRCC3, RAD51C and RAD51D in the DSB repair via homologous recombination is of less importance in comparison to RAD54, as RAD54 deficient cells demonstrated complete absence of SLD recovery

  9. Split high‐dose oral levothyroxine treatment as a successful therapy option in myxedema coma

    OpenAIRE

    Charoensri, Suranut; Sriphrapradang, Chutintorn; Nimitphong, Hataikarn

    2017-01-01

    Key Clinical Message High‐dose intravenous thyroxine (T4) is the preferable treatment for myxedema coma. We describe the clinical course of a 69‐year‐old man who presented with myxedema coma and received oral levothyroxine (LT4) therapy (1 mg) in a split dose. This suggests split high‐dose oral LT4 as a therapeutic option in myxedema coma.

  10. Adaptive repair induced by small doses of γ radiation in repair-defective human cells

    International Nuclear Information System (INIS)

    Zasukhina, G.D.; L'vova, G.N.; Vasil'eva, I.M.; Sinel'shchikova, T.A.; Semyachkina, A.N.

    1993-01-01

    Adaptive repair induced by small doses of gamma radiation was studied in repair-defective xeroderma pigmentosum, gout, and homocystinuria cells. The adaptation of cells induced by small doses of radiation was estimated after subsequent exposure to gamma radiation, 4-nitroquinoline-1-oxide, and N-methyl-N-nitro-N-nitrosoguanidine by three methods: (1) by the reduction in DNA breaks; (2) by induction of resistant DNA synthesis; and (3) by increased reactivation of vaccinia virus. The three cell types in response to the three different mutagens revealed differences in the mechanism of cell defense in excision repair, in the adaptive response, and in Weigl reactivation

  11. The influence of split doses of γ-radiation on human erythrocytes

    International Nuclear Information System (INIS)

    Koziczak, R.; Gonciarz, M.; Krokosz, A.; Szweda-Lewandowska, Z.

    2003-01-01

    Human erythrocyte suspensions in an isotonic Na-phosphate buffer, pH 7.4, of hematocrit of 2% were exposed under air to gamma radiation at a dose rate of 2.2 kGy. Erythrocytes were irradiated with single doses, and identical doses split into two fractions with an interval time of 3.5 h between following exposures. The obtained results indicated that the irradiation of enucleated human erythrocytes with split doses caused a reduction of hemolysis (2.4 times), a decrease in the level of damage to membrane lipids and the contents of MetHb, compared with identical single doses. However, the splitting of radiation doses did not change the level of damage to the membrane proteins, as was estimated with a maleimide spin label. The obtained results suggest that a decrease in the level of damage to lipids was related to a decrease in hemolysis. (author)

  12. Isoniazid, pyrazinamide and rifampicin content variation in split fixed-dose combination tablets.

    Science.gov (United States)

    Pouplin, Thomas; Phuong, Pham Nguyen; Toi, Pham Van; Nguyen Pouplin, Julie; Farrar, Jeremy

    2014-01-01

    In most developing countries, paediatric tuberculosis is treated with split tablets leading to potential inaccuracy in the dose delivery and drug exposure. There is no data on the quality of first-line drugs content in split fixed-dose combination tablets. To determine Isoniazid, Pyrazinamide and Rifampicin content uniformity in split FDC tablets used in the treatment of childhood tuberculosis. Drug contents of 15 whole tablets, 30 half tablets and 36 third tablets were analysed by high performance liquid chromatography. The content uniformity was assessed by comparing drug content measured in split portions with their expected amounts and the quality of split portions was assessed applying qualitative specifications for whole tablets. All whole tablets measurements fell into the USP proxy for the three drugs. But a significant number of half and third portions was found outside the tolerated variation range and the split formulation failed the requirements for content uniformity. To correct for the inaccuracy of splitting the tablets into equal portions, a weight-adjustment strategy was used but this did not improve the findings. In split tablets the content of the three drugs is non-uniform and exceeded the USP recommendations. There is an absolute need to make child-friendly formulations available for the treatment of childhood tuberculosis.

  13. Hematopoietic tissue repair under chronic low daily dose irradiation

    International Nuclear Information System (INIS)

    Seed, T.M.

    1994-01-01

    The capacity of the hematopoietic system to repair constantly accruing cellular damage under chronic, low daily dose gamma irradiation is essential for the maintenance of a functional hematopoietic system, and, in turn, long term survival. In certain individuals, however, such continuous cycles of damage and repair provide an essential inductive environment for selected types of hematopathologies, e.g., myeloid leukemia (ML). We have been studying temporal and causal relationships between hematopoietic capacity, associated repair functions, and propensities for hematologic disease in canines under variable levels of chronic radiation stress (0.3-26.3 cGy d -1 ). Results indicate that the maximum exposure rate tolerated by the hematopoietic system is highly individual-specific and is based largely on the degree to which repair capacity, and, in turn, hematopoietic restoration, is augmented under chronic exposure. In low-tolerance individuals (prone to aplastic anemia, subgroup (1), the failure to augment basic m-pair functions seemingly results in a progressive accumulation of genetic and cellular damage within vital progenitorial marrow compartments particularly marked within erythroid compartments. that results in loss of reproductive capacity and ultimately in collapse of the hematopoietic system. The high-tolerance individuals (radioaccomodated and either prone- or not prone to ML, subgroup 2 ampersand 3 appear to minimize the accumulating damage effect of daily exposures by extending repair functions, which preserves reproductive integrity and fosters regenerative hematopoietic responses. As the strength of the regenerative response manifests the extent of repair augmentation, the relatively strong response of high- tolerance individuals progressing to patent ML suggests an insufficiency of repair quality rather than repair quantity

  14. Use of 99mTc-bicisate in activation studies by split-dose technique

    DEFF Research Database (Denmark)

    Holm, S; Madsen, P L; Sperling, B

    1994-01-01

    The properties of the brain single photon emission computed tomography (SPECT) tracer 99mTc-bicisate (ethyl cysteinate dimer) were examined in regard to its use in test-retest studies with short-interval, split-dose studies. The stimulus applied in these tests was a visual activation by a "flicke......The properties of the brain single photon emission computed tomography (SPECT) tracer 99mTc-bicisate (ethyl cysteinate dimer) were examined in regard to its use in test-retest studies with short-interval, split-dose studies. The stimulus applied in these tests was a visual activation...

  15. Mutation induction in haploid yeast after split-dose radiation-exposure. Pt. 1

    International Nuclear Information System (INIS)

    Schenk, K.; Zoelzer, F.; Kiefer, J.

    1989-01-01

    Mutation induction was investigated in wild-type haploid yeast Saccharomyces cerevisiae after split-dose UV-irradiation. Cells were exposed to fractionated 254 nm-UV-doses separated by intervals from 0 to 6 h with incubation either on non-nutrient or nutrient agar between. The test parameter was resistance to canavanine. If modifications of sensitivity due to incubation are appropriately taken into account there is no change of mutation frequency. (orig.)

  16. Superiority of split dose midazolam as conscious sedation for outpatient colonoscopy.

    Science.gov (United States)

    Lee, Hyuk; Kim, Jeong Hwan

    2009-08-14

    To elucidate the efficacy and safety of a split dose of midazolam in combination with meperidine for colonoscopy. Eighty subjects undergoing outpatient colonoscopy were randomly assigned to group A or B. Group A (n = 40) received a split dose of midazolam in combination with meperidine. Group B (n = 40) received a single dose of midazolam in combination with meperidine. Outcome measurements were level of sedation, duration of sedation and recovery, degree of pain and satisfaction, procedure-related memory, controllability, and adverse events. Group A had a lower frequency of significant hypoxemia (P = 0.043) and a higher sedation score on withdrawal of the endoscope from the descending colon than group B (P = 0.043). Group B recovered from sedation slightly sooner than group A (P memory, except insertion-related memory, were lower in group A one week after colonoscopic examination (P = 0.018 and P sedation status during colonoscopic examination and a reduction in procedure-related pain and memory, but resulted in longer recovery time.

  17. An experimental study on the alteration of thermal enhancement ratio by combination of split dose hyperthermia irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sun Ok; Kim, Hee Seup [Ewha Womens University College of Medicine, Seoul (Korea, Republic of)

    1983-06-15

    The study was undertaken to evaluate the alteration of thermal enhancement ratio as a function of time intervals between two split dose hyperthermias followed by irradiation. For the experiments, 330 mice were divided into 3 groups; the first, 72 mice were used to evaluate the heat reaction by single dose hyperthermia and heat resistance by split dose hyperthermia, the second, 36 mice were used to evaluate the radiation reaction by irradiation only, and the third, 222 mice were used for TER observation by combination of single dose hyperthermia and irradiation, and TER alteration by combination of split dose hyperthermia and irradiation. For each group the skin reaction score of mouse tail was used for observation and evaluation of the result of heat and irradiation. The results obtained are summarized as follows: 1. The heating time resulting 50% necrosis (ND{sub 5}0) Was 101 minutes in 43 .deg. C and 24 minutes in 45 .deg. C hyperthermia, which indicated that three is reciprocal proportion between temperature and heating time. 2. Development of heat resistance was observed by split dose hyperthermia. 3. The degree of skin reaction by irradiation only was increased proportionally as a function of radiation dose, and calculated radiation dose corresponding to skin score 1.5 (D{sub 1}.5) was 4,137 rads. 4. Obtained thermal enhancement ratio by combination of single dose hyperthermia and irradiation was increased proportionally as a function of heating time. 5. Thermal enhancement ratio was decreased by combination of split dose hyperthermia and irradiation, which was less intense and lasted longer than development of heat resistance. In summary, these studies indicate that the alteration of thermal enhancement ratio has influence on heat resistance by split dose hyperthermia and irradiation.

  18. Continuous Aspirin Use Does Not Increase Bleeding Risk of Split-Thickness Skin Transplantation Repair to Chronic Wounds.

    Science.gov (United States)

    Sun, Yanwei; Wang, Yibing; Li, Liang; Zhang, Zheng; Wang, Ning; Wu, Dan

    Discontinuation of aspirin therapy before cutaneous surgery may cause serious complications. The aim of this prospective study was to evaluate the bleeding risk of split-thickness skin transplantation repair to chronic wounds in patients on aspirin therapy. A total of 97 patients who underwent split-thickness skin transplantation surgery of chronic wounds during a 2-year period were enrolled. They were categorized on the basis of aspirin therapies. The primary outcome was postoperative bleeding and bleeding complications. Univariate analysis was performed to examine the association between aspirin and bleeding complications. Among the 26 patients taking aspirin continuously in group A, there were 5 bleeding complications (19.23%). Among the 55 nonusers in group B, there were 10 bleeding complications (18.18%). Among the 16 discontinuous patients in group C, there were 3 bleeding complications (18.75%). No statistical differences were found among the groups ( P = .956). Univariate analysis showed that continuous aspirin use was not significantly associated with bleeding complications (odds ratio, 0.933; 95% confidence interval, 0.283-3.074; P = .910 in the aspirin and control groups) and that discontinuous aspirin use was not significantly associated with bleeding complications (odds ratio, 0.963; 95% confidence interval, 0.230-4.025; P = .959 in the aspirin and control groups; odds ratio, 0.969; 95% confidence interval, 0.198-4.752; P = .969 in the aspirin and discontinuous groups). Continuous aspirin use does not produce an additional bleeding risk in patients who undergo split-thickness skin transplantation repair of chronic wounds.

  19. Effects of low dose radiation on repair processes in human lymphocytes

    International Nuclear Information System (INIS)

    Tuschl, H.; Altmann, H.; Kovac, R.; Topaloglou, A.; Egg, D.; Guenther, R.

    1978-10-01

    DNA excision repair was investigated in lymphocytes of persons occupationally exposed to low dose radiation of 222 Rn. Autoradiographic studies of unscheduled DNA synthesis and measurement of 3 H-thymidine incorporation by repair replication into double stranded and single-strand containing DNA fractions obtained by BND cellulose chromatography seem to indicate a stimulatory effect of repeated low dose radiation on repair enzymes. (author)

  20. The importance of triggering dose and conditions of split dose incubation to the development of thermotolerance

    International Nuclear Information System (INIS)

    Chang, P.Y.; Blakely, E.A.

    1987-01-01

    We have observed a lack of development of thermotolerance in CHO-TSH1, a protein synthetic mutant hamster cell line, under continuous heat stress treatments of 41.5 0 C, 42 0 C, and 42.5 0 C. The parental CHO-SC1 line develops thermotolerance under similar conditions. During the past year we have further examined this phenomenon in the mutant by studying the role of the level of the triggering heat dose and the time of administration to the ultimate development of thermotolerance. By increasing the temperature of the triggering dose for a brief interval, followed by the time at the permissive temperature, we were able to induce the development of thermotolerance in the protein-synthetic mutant cell. 4 refs., 2 figs

  1. 'Regular' and 'emergency' repair

    International Nuclear Information System (INIS)

    Luchnik, N.V.

    1975-01-01

    Experiments on the combined action of radiation and a DNA inhibitor using Crepis roots and on split-dose irradiation of human lymphocytes lead to the conclusion that there are two types of repair. The 'regular' repair takes place twice in each mitotic cycle and ensures the maintenance of genetic stability. The 'emergency' repair is induced at all stages of the mitotic cycle by high levels of injury. (author)

  2. Defective recovery of semi-conservative DNA synthesis in xeroderma pigmentosum cells following split-dose ultraviolet irradiation

    International Nuclear Information System (INIS)

    Moustacchi, E.; Ehmann, U.K.; Friedberg, E.C.

    1979-01-01

    In normal human fibroblasts the authors observe an enhancement of the recovery of the rate of semi-conservative DNA synthesis after split-dose UV-irradation relative to a single total UV dose. The enhanced recovery is totally absent in both a xeroderma pigmentosum variant line and two xeroderma pigmentosum lines belonging to complementation groups A and C. (Auth.)

  3. Effects of split-dose irradiation of the rabbit's eye - a histopathological study

    International Nuclear Information System (INIS)

    Grabenbauer, G.G.

    1987-01-01

    Thirty-six rabbits were included in a study investigating into the effects of split-dose 300 KV X-irradiation on the cornea, ciliary body, nictitating membrane and lacrimal gland. In each animal, soly the right the eye was irradiated using total doses of 21 Gy, 30 Gy, 36 Gy and 45 Gy that were administered according to a fixed schedule in fractions of 3 Gy five times per week. After latency periods of six weeks, three months and six months the animals receiving 21 Gy, 30 Gy and 36 Gy showed no changes of the bulbi, eye lids and lacrimal glands that could be ascertained by histopathological evaluation. In the animals exposed to the 45 Gy dose, changes of the cornea and conjunctiva caused by radiation injuries to the lacrimal glands and conjunctival goblet cells started to appear after a minimum period of 3 months. This dose level was also the threshold for the occurrence of corneal damage or even ulceration as a result of secondary reduction or qualitative change of lacrimal secretions. (ECB) [de

  4. Induction of lacI- mutations in Escherichia coli cells after single and split-dose irradiation

    International Nuclear Information System (INIS)

    Kozubek, S.; Ryznar, L.

    1992-01-01

    In the lacI system of Escherichia coli, X-ray mutagenesis follows a linear-quadratic curve with suppression; the survival curve is exponential. Dose fractionation leads to nearly complete repair of premutational lesions during an incubation interval of 3.5 h. Repair starts with a delay of 1.5-2 h, suggesting the involvement of an inducible repair/mutation fixation system. The dose-dependence of mutagenesis is described by a simple model assuming two hits being required. A probable explanation might be that the premutagenic lesions consist of two closely spaced lesions on the opposite strands of the DNA molecule. (author)

  5. Phenotypic characterization of thymic prelymphoma cells of B10 mice treated with split-dose irradiation

    International Nuclear Information System (INIS)

    Muto, M.; Kubo, E.; Kamisaku, H.; Sado, T.

    1990-01-01

    Using an intrathymic injection assay on B10 Thy-1 congenic mice, it was demonstrated that thymic prelymphoma cells first developed within the thymuses from 4 to 8 days after split-dose irradiation and were detected in more than 63% of the test donor thymuses when examined at 21 and 31 days after irradiation. Moreover, some mice (25%) at 2 mo after split-dose irradiation had already developed thymic lymphomas in their thymuses. To characterize these thymic prelymphoma cells, the thymocytes from B10 Thy-1.1 mice 1 mo after irradiation were stained with anti-CD4 and anti-CD8 mAb and were sorted into four subpopulations. These fractionated cells were injected into the recipient thymuses to examine which subpopulation contained thymic prelymphoma cells. The results indicated that thymic prelymphoma cells existed mainly in CD4- CD8- and CD4- CD8+ thymocyte subpopulations and also in CD4+ CD8+ subpopulation. T cell lymphomas derived from CD4- CD8- prelymphoma cells had mainly CD4- CD8- or CD4- CD8+ phenotypes. T cell lymphomas developed from CD4- CD8+ prelymphoma cells mainly expressed CD4- CD8+ or CD4+ CD8+ phenotype. T cell lymphomas originating from CD4+ CD8+ prelymphoma cells were mainly CD4+ CD8+ but some CD4- CD8+ or CD4+ CD8- cells were also present. These thymic prelymphoma cells were further characterized phenotypically in relation to their expression of the marker defined by the mAb against J11d marker and TL-2 (thymus-leukemia) Ag, which is not expressed on normal thymocytes of B10.Thy-1.2 or B10.Thy-1.1 strain, but appears on the thymocytes of lymphomagenic irradiated mice. The results indicated that the prelymphoma cells existed in J11d+, TL-2+ cells

  6. An Automated Inpatient Split-dose Bowel Preparation System Improves Colonoscopy Quality and Reduces Repeat Procedures.

    Science.gov (United States)

    Yadlapati, Rena; Johnston, Elyse R; Gluskin, Adam B; Gregory, Dyanna L; Cyrus, Rachel; Werth, Lindsay; Ciolino, Jody D; Grande, David P; Keswani, Rajesh N

    2017-07-19

    Inpatient colonoscopy preparations are often inadequate, compromising patient safety and procedure quality, while resulting in greater hospital costs. The aims of this study were to: (1) design and implement an electronic inpatient split-dose bowel preparation order set; (2) assess the intervention's impact upon preparation adequacy, repeated colonoscopies, hospital days, and costs. We conducted a single center prospective pragmatic quasiexperimental study of hospitalized adults undergoing colonoscopy. The experimental intervention was designed using DMAIC (define, measure, analyze, improve, and control) methodology. Prospective data collected over 12 months were compared with data from a historical preintervention cohort. The primary outcome was bowel preparation quality and secondary outcomes included number of repeated procedures, hospital days, and costs. On the basis of a Delphi method and DMAIC process, we created an electronic inpatient bowel preparation order set inclusive of a split-dose bowel preparation algorithm, automated orders for rescue medications, and nursing bowel preparation checks. The analysis data set included 969 patients, 445 (46%) in the postintervention group. The adequacy of bowel preparation significantly increased following intervention (86% vs. 43%; P<0.01) and proportion of repeated procedures decreased (2.0% vs. 4.6%; P=0.03). Mean hospital days from bowel preparation initiation to discharge decreased from 8.0 to 6.9 days (P=0.02). The intervention resulted in an estimated 1-year cost-savings of $46,076 based on a reduction in excess hospital days associated with repeated and delayed procedures. Our interdisciplinary initiative targeting inpatient colonoscopy preparations significantly improved quality and reduced repeat procedures, and hospital days. Other institutions should consider utilizing this framework to improve inpatient colonoscopy value.

  7. DNA excision repair as a component of adaptation to low doses of ionizing radiation Escherichia coli

    International Nuclear Information System (INIS)

    Huang, H.; Claycamp, H.G.

    1993-01-01

    In this study the authors examined whether or not DNA excision repair is a component of adaptation induced by very low-dose ionizing radiation in Escherichia coli, a well-characterized prokaryote, and investigated the relationship between enhanced excision repair and the SOS response. Their data suggest that there seems to be narrow 'windows' of dose-effect for the induction of SOS-independent DNA excision repair. Being similar to mammalian cell studies, the dose range for this effect was about 200-fold less than D 37 for radiation survival. (author)

  8. Efficacy of prokinetics with a split-dose of polyethylene glycol in bowel preparation for morning colonoscopy: a randomized controlled trial.

    Science.gov (United States)

    Kim, Hyoung Jun; Kim, Tae Oh; Shin, Bong Chul; Woo, Jae Gon; Seo, Eun Hee; Joo, Hee Rin; Heo, Nae-Yun; Park, Jongha; Park, Seung Ha; Yang, Sung Yeon; Moon, Young Soo; Shin, Jin-Yong; Lee, Nae Young

    2012-01-01

    Currently, a split-dose of polyethylene glycol (PEG) is the mainstay of bowel preparation due to its tolerability, bowel-cleansing action, and safety. However, bowel preparation with PEG is suboptimal because residual fluid reduces the polyp detection rate and requires a more thorough colon inspection. The aim of our study was to demonstrate the efficacy of a sufficient dose of prokinetics on bowel cleansing together with split-dose PEG. A prospective endoscopist-blinded study was conducted. Patients were randomly allocated to two groups: prokinetic with split-dose PEG or split-dose PEG alone. A prokinetic [100 mg itopride (Itomed)], was administered twice simultaneously with each split-dose of PEG. Bowel-cleansing efficacy was measured by endoscopists using the Ottawa scale and the segmental fluidity scale score. Each participant completed a bowel preparation survey. Mean scores from the Ottawa scale, segmental fluid scale, and rate of poor preparation were compared between both groups. Patients in the prokinetics with split-dose PEG group showed significantly lower total Ottawa and segmental fluid scores compared with patients in the split-dose of PEG alone group. A sufficient dose of prokinetics with a split-dose of PEG showed efficacy in bowel cleansing for morning colonoscopy, largely due to the reduction in colonic fluid. Copyright © 2012 S. Karger AG, Basel.

  9. Radiation sensitivity for delayed reproductive death (DRD) following single or split-dose irradiation

    International Nuclear Information System (INIS)

    Hagemann, G.; Lipfert, C.H.; Wueppen, G.

    2001-01-01

    Materials and Methods: CHO-cells of a sub clone of the line T71 have a spontaneous cell loss rate of l of the DRD can be defined as the proportional factor of the linear relationship between the MCD on one side and the dose K x the cell division factor m on the other side. E l is dependent on the age of the cells during irradiation and the cell line. The slope of the dually logarithmic growth curve of the cell population is: s=1-E l . K. Experimentally E l was found to be equal for single and split dose irradiation and amounted to E l =0.065 with s d =±0.004. - Literature analysis for the mathematical estimation of E l . K was based on reports of measurements of the local tumor recurrence growth of carcinomas and sarcomas of rodents and pulmonary metastases of sarcomas in humans, respectively, after fractional irradiation. We obtained values of ≤E l . K≤0.77. Values for E l are independent of the dose and lie considerably below data derived from in-vitro measurements of different cell cultures. Conclusions: Since recurrence kinetics of tumors are determined by the radiation sensitivity E l of the DRD, E l can be used for estimating the kinetics of tumor recurrence. As lately described, MCD is linearly proportional to the micro-nucleus frequency. Determinations of the micro-nucleus frequencies in tumor cell biopsies pre and post radiation onset offer the option for developing a fast predictive assay. Organ malformations of embryos after exposition to ionizing radiation can be mathematically deduced by DRD to the partial cell mortality. (orig.) [de

  10. Mathematical simulation of dose fields in the planning of repair stuff irradiation

    International Nuclear Information System (INIS)

    Tashlykov, O.L.; Shcheklein, S.E.; Markelov, N.I.

    2004-01-01

    The role of planning stage in the cycle of optimization when organizing repair works at NPPs is discussed. The methods used for forecasting irradiation doses for personnel engaged in repair works are considered. The importance of the problems of simulating the doses connected with estimation of dose rate values in different points of the working area and working time period in corresponding radiation fields is shown. The calculated data on distributions of γ radiation dose rate fields from surface and linear sources are given [ru

  11. Mutation induction in haploid yeast after split-dose radiation-exposure. I. Fractionated UV-irradiation.

    Science.gov (United States)

    Schenk, K; Zölzer, F; Kiefer, J

    1989-01-01

    Mutation induction was investigated in wild-type haploid yeast Saccharomyces cerevisiae after split-dose UV-irradiation. Cells were exposed to fractionated 254 nm-UV-doses separated by intervals from 0 to 6 h with incubation either on non-nutrient or nutrient agar between. The test parameter was resistance to canavanine. If modifications of sensitivity due to incubation are appropriately taken into account there is no change of mutation frequency.

  12. The effect of low radiation doses on DNA repair processes

    International Nuclear Information System (INIS)

    Tuschl, H.

    1978-08-01

    Error free DNA repair processes are an important preprequisite for the maintenance of genetic integrity of cells. They are of special importance for persons therapeutically or occupationally exposed to radiation. Therefore the effect of radiation therapy and elevated natural background radiation on unscheduled DNA synthesis was tested in peripheral lymphocytes of exposed persons. Both, autoradiographic studies of unscheduled DNA synthesis and measurement of 3 H-thymidine uptake into double stranded and single-strand containing DNA fractions revealed an increase of capacity for DNA repair. (author)

  13. Protective effect of hypoxia in the ram testis during single and split-dose X-irradiation

    International Nuclear Information System (INIS)

    Vliet, J. van; Wensing, C.J.G.; Bootsma, A.L.; Peperzeel, H.A. van; Schipper, J.

    1988-01-01

    Spertogonial stem-cell survival in the ram was studied after single (6Gy) and split-dose X-irradiation both under normal and hypoxic conditions. Hypoxia was induced by inflation of an occluder implanted around the testicular artery. The occluders were inflated about 10 min before irradiation and deflated immediately after. Stem-cell survival was measured at 5 or 7 weeks after irradiation by determination of the Repopulation Index (RI) in histological testis sections. The RI-values after fractionated irradiation were only half those after single dose irradiation. Hypoxia had a protective effect on the stem-cell survival. After split-dose irradiation under hypoxic conditions two times more stem cells survived than under normal oxic conditions; the RI-values increased from 34% (oxic) to 68% (hypoxic). This effect of hypoxia was also found after single dose irradiation where the RI-values increased from 68% (oxic) to 84% (hypoxic). The development of the epithelium in repopulated tubules was also studied. Under hypoxia, a significantly higher fraction of tubules with complete epithelium was found after single (38 vs. 4%) as well as after split-dose irradiation (12 vs. 0%)

  14. Three-dimensional dose accumulation in pseudo-split-field IMRT and brachytherapy for locally advanced cervical cancer.

    Science.gov (United States)

    Sun, Baozhou; Yang, Deshan; Esthappan, Jackie; Garcia-Ramirez, Jose; Price, Samantha; Mutic, Sasa; Schwarz, Julie K; Grigsby, Perry W; Tanderup, Kari

    2015-01-01

    Dose accumulation of split-field external beam radiotherapy (EBRT) and brachytherapy (BT) is challenging because of significant EBRT and BT dose gradients in the central pelvic region. We developed a method to determine biologically effective dose parameters for combined split-field intensity-modulated radiation therapy (IMRT) and image-guided BT in locally advanced cervical cancer. Thirty-three patients treated with split-field-IMRT to 45.0-51.2 Gy in 1.6-1.8 Gy per fraction to the elective pelvic lymph nodes and to 20 Gy to the central pelvis region were included in this study. Patients received six weekly fractions of high-dose rate BT to 6.5-7.3 Gy per fraction. A dose tracker software was developed to compute the equivalent dose in 2-Gy fractions (EQD2) to gross tumor volume (GTV), organs-at-risk and point A. Total dose-volume histogram parameters were computed on the 3D combined EQD2 dose based on rigid image registration. The dose accumulation uncertainty introduced by organ deformations between IMRT and BT was evaluated. According to International Commission on Radiation Unit and Measurement and GEC European Society for Therapeutic Radiology and Oncology recommendations, D98, D90, D50, and D2cm3 EQD2 dose-volume histogram parameters were computed. GTV D98 was 84.0 ± 26.5 Gy and D2cc was 99.6 ± 13.9 Gy, 67.4 ± 12.2 Gy, 75.0 ± 10.1 Gy, for bladder, rectum, and sigmoid, respectively. The uncertainties induced by organ deformation were estimated to be -1 ± 4 Gy, -3 ± 5 Gy, 2 ± 3 Gy, and -3 ± 5 Gy for bladder, rectum, sigmoid, and GTV, respectively. It is feasible to perform 3D EQD2 dose accumulation to assess high and intermediate dose regions for combined split-field IMRT and BT. Copyright © 2015 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  15. γ-ray dose rate effect in DNA double-strand break repair deficient murine cells

    International Nuclear Information System (INIS)

    Li Liya; Li Peiwen

    2002-01-01

    Objective: To analyze the dose rate effect and potentially lethal damage repair in DNA double-strand break repair deficient murine cells (SCID) irradiated by γ-ray. Methods: The wild type (CB.17+/+) and SCID cells were exposed to γ-ray at high and low dose rates. The high dose rate exposure was fractionated into two equal doses at 24 h intervals. The survival rates of irradiated cells were calculated by clone-forming analysis. Results: When γ-ray was given to wild type (CB.17+/+) cells in two fractions at 24 h intervals, the survival rate was significantly higher than that when the same total dose was given singly. In contrast, there was no difference in the survival rates between the single and fractionated exposure in SCID cells. SCID cells were more sensitive than CB.17+/+ cells to both low and high dose rates γ-ray exposure for cell killing. The survival rate by low dose rate exposure was significantly higher than that by high dose rate exposure, not only in CB.17+/+ cells but also in SCID cells. Conclusions: SCID cells are deficient in repairing γ-ray induced double-strand breaks. There is dose rate effect in both SCID and CB.17+/+ cells

  16. Implications of tissue target-cell survival-curve shape for values of split-dose recovery doses: late versus early effects

    International Nuclear Information System (INIS)

    Redpath, J.L.; Peel, D.M.; Hopewell, J.W.

    1984-01-01

    Recent data from this laboratory on split-dose recovery for early and late effects in pig skin are consistent with the linear-quadratic model for cell survival, and with relative cell survival-curve shapes for early- and late-effect target cells where the early-effect cells have an intially steeper and straighter survival-curve than the late-effect cells. (author)

  17. Three-dimensional dose accumulation in pseudo-split-field IMRT and brachytherapy for locally advanced cervical cancer

    DEFF Research Database (Denmark)

    Sun, Baozhou; Yang, Deshan; Esthappan, Jackie

    2015-01-01

    -field intensity-modulated radiation therapy (IMRT) and image-guided BT in locally advanced cervical cancer. METHODS AND MATERIALS: Thirty-three patients treated with split-field-IMRT to 45.0-51.2 Gy in 1.6-1.8 Gy per fraction to the elective pelvic lymph nodes and to 20 Gy to the central pelvis region were...... included in this study. Patients received six weekly fractions of high-dose rate BT to 6.5-7.3 Gy per fraction. A dose tracker software was developed to compute the equivalent dose in 2-Gy fractions (EQD2) to gross tumor volume (GTV), organs-at-risk and point A. Total dose-volume histogram parameters were...

  18. Split-Course, High-Dose Palliative Pelvic Radiotherapy for Locally Progressive Hormone-Refractory Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Gogna, Nirdosh Kumar, E-mail: kumar_gogna@health.qld.gov.au [Radiation Oncology Services, Mater Centre, Brisbane, Queensland (Australia); Baxi, Siddhartha; Hickey, Brigid; Baumann, Kathryn [Radiation Oncology Services, Mater Centre, Brisbane, Queensland (Australia); Burmeister, Elizabeth [Princess Alexandra Hospital, Brisbane, Queensland (Australia); Holt, Tanya [Radiation Oncology Services, Mater Centre, Brisbane, Queensland (Australia)

    2012-06-01

    Purpose: Local progression, in patients with hormone-refractory prostate cancer, often causes significant morbidity. Pelvic radiotherapy (RT) provides effective palliation in this setting, with most published studies supporting the use of high-dose regimens. The aim of the present study was to examine the role of split-course hypofractionated RT used at our institution in treating this group of patients. Methods and Materials: A total of 34 men with locoregionally progressive hormone-refractory prostate cancer, treated with a split course of pelvic RT (45-60 Gy in 18-24 fractions) between 2000 and 2008 were analyzed. The primary endpoints were the response rate and actuarial locoregional progression-free survival. Secondary endpoints included overall survival, compliance, and acute and late toxicity. Results: The median age was 71 years (range, 53-88). Treatment resulted in an overall initial response rate of 91%, a median locoregional progression-free survival of 43 months, and median overall survival of 28 months. Compliance was excellent and no significant late toxicity was reported. Conclusions: The split course pelvic RT described has an acceptable toxicity profile, is effective, and compares well with other high-dose palliative regimens that have been previously reported.

  19. Chromosomal Aberrations in DNA Repair Defective Cell Lines: Comparisons of Dose Rate and Radiation Quality

    Science.gov (United States)

    George, K. A.; Hada, M.; Patel, Z.; Huff, J.; Pluth, J. M.; Cucinotta, F. A.

    2009-01-01

    Chromosome aberration yields were assessed in DNA double-strand break repair (DSB) deficient cells after acute doses of gamma-rays or high-LET iron nuclei, or low dose-rate (0.018 Gy/hr) gamma-rays. We studied several cell lines including fibroblasts deficient in ATM (product of the gene that is mutated in ataxia telangiectasia patients) or NBS (product of the gene mutated in the Nijmegen breakage syndrome), and gliomablastoma cells that are proficient or lacking in DNA-dependent protein kinase, DNA-PK activity. Chromosomes were analyzed using the fluorescence in-situ hybridization (FISH) chromosome painting method in cells at the first division post-irradiation and chromosome aberrations were identified as either simple exchanges (translocations and dicentrics) or complex exchanges (involving >2 breaks in 2 or more chromosomes). Gamma radiation induced higher yields of both simple and complex exchanges in the DSB repair defective cells than in the normal cells. The quadratic dose-response terms for both chromosome exchange types were significantly higher for the ATM and NBS defective lines than for normal fibroblasts. However, the linear dose-response term was significantly higher only for simple exchanges in the NBS cells. Large increases in the quadratic dose response terms indicate the important roles of ATM and NBS in chromatin modifications that facilitate correct DSB repair and minimize aberration formation. Differences in the response of AT and NBS deficient cells at lower doses suggests important questions about the applicability of observations of radiation sensitivity at high dose to low dose exposures. For all iron nuclei irradiated cells, regression models preferred purely linear and quadratic dose responses for simple and complex exchanges, respectively. All the DNA repair defective cell lines had lower Relative biological effectiveness (RBE) values than normal cells, the lowest being for the DNA-PK-deficient cells, which was near unity. To further

  20. The optimal fraction size in high-dose-rate brachytherapy: dependency on tissue repair kinetics and low-dose rate

    International Nuclear Information System (INIS)

    Sminia, Peter; Schneider, Christoph J.; Fowler, Jack F.

    2002-01-01

    Background and Purpose: Indications of the existence of long repair half-times on the order of 2-4 h for late-responding human normal tissues have been obtained from continuous hyperfractionated accelerated radiotherapy (CHART). Recently, these data were used to explain, on the basis of the biologically effective dose (BED), the potential superiority of fractionated high-dose rate (HDR) with large fraction sizes of 5-7 Gy over continuous low-dose rate (LDR) irradiation at 0.5 Gy/h in cervical carcinoma. We investigated the optimal fraction size in HDR brachytherapy and its dependency on treatment choices (overall treatment time, number of HDR fractions, and time interval between fractions) and treatment conditions (reference low-dose rate, tissue repair characteristics). Methods and Materials: Radiobiologic model calculations were performed using the linear-quadratic model for incomplete mono-exponential repair. An irradiation dose of 20 Gy was assumed to be applied either with HDR in 2-12 fractions or continuously with LDR for a range of dose rates. HDR and LDR treatment regimens were compared on the basis of the BED and BED ratio of normal tissue and tumor, assuming repair half-times between 1 h and 4 h. Results: With the assumption that the repair half-time of normal tissue was three times longer than that of the tumor, hypofractionation in HDR relative to LDR could result in relative normal tissue sparing if the optimum fraction size is selected. By dose reduction while keeping the tumor BED constant, absolute normal tissue sparing might therefore be achieved. This optimum HDR fraction size was found to be largely dependent on the LDR dose rate. On the basis of the BED NT/TUM ratio of HDR over LDR, 3 x 6.7 Gy would be the optimal HDR fractionation scheme for replacement of an LDR scheme of 20 Gy in 10-30 h (dose rate 2-0.67 Gy/h), while at a lower dose rate of 0.5 Gy/h, four fractions of 5 Gy would be preferential, still assuming large differences between tumor

  1. Split-bolus CT-urography using dual-energy CT: Feasibility, image quality and dose reduction

    Energy Technology Data Exchange (ETDEWEB)

    Takeuchi, Mitsuru, E-mail: m2rbimn@gmail.com [Nagoya City University Graduate School of Medical Sciences, Department of Radiology, 1 Kawasumi Mizuho-cho, Mizuho-ku, Nagoya, 467-8601 (Japan); Kawai, Tatsuya; Ito, Masato; Ogawa, Masaki [Nagoya City University Graduate School of Medical Sciences, Department of Radiology, 1 Kawasumi Mizuho-cho, Mizuho-ku, Nagoya, 467-8601 (Japan); Ohashi, Kazuya [Nagoya City University Hospital, Department of Radiology, 1 Kawasumi Mizuho-cho, Mizuho-ku, Nagoya, 467-8601 (Japan); Hara, Masaki; Shibamoto, Yuta [Nagoya City University Graduate School of Medical Sciences, Department of Radiology, 1 Kawasumi Mizuho-cho, Mizuho-ku, Nagoya, 467-8601 (Japan)

    2012-11-15

    Purpose: To prospectively evaluate the feasibility of dual-energy (DE) split-bolus CT-urography (CTU) and the quality of virtual non-enhanced images (VNEI) and DE combined nephrographic-excretory phase images (CNEPI), and to estimate radiation dose reduction if true non-enhanced images (TNEI) could be omitted. Patients and methods: Between August and September 2011, 30 consecutive patients with confirmed or suspected urothelial cancer or with hematuria underwent DE CT. Single-energy TNEI and DE CNEPI were obtained. VNEI was reconstructed from CNEPI. Image quality of CNEPI and VNEI was evaluated using a 5-point scale. The attenuation of urine in the bladder on TNEI and VNEI was measured. The CT dose index volume (CTDI (vol)) of the two scans was recorded. Results: The mean image quality score of CNEPI and VNEI was 4.7 and 3.3, respectively. The mean differences in urine attenuation between VNEI and TNEI were 14 {+-} 15 [SD] and -16 {+-} 29 in the anterior and posterior parts of the bladder, respectively. The mean CTDI (vol) for TNEI and CNEPI was 11.8 and 10.9 mGy, respectively. Omission of TNEI could reduce the total radiation dose by 52%. Conclusion: DE split-bolus CTU is technically feasible and can reduce radiation exposure; however, an additional TNEI scan is necessary when the VNEI quality is poor or quantitative evaluation of urine attenuation is required.

  2. Implementation of a split-bolus single-pass CT protocol at a UK major trauma centre to reduce excess radiation dose in trauma pan-CT

    International Nuclear Information System (INIS)

    Leung, V.; Sastry, A.; Woo, T.D.; Jones, H.R.

    2015-01-01

    Aim: To quantify the dose reduction and ensure that the use of a split-bolus protocol provided sufficient vascular enhancement. Materials and methods: Between 1 January 2014 and 31 May 2014, both split bolus and traditional two-phase scans were performed on a single CT scanner (SOMATOM Definition AS+, Siemens Healthcare) using a two-pump injector (Medrad Stellant). Both protocols used Siemens' proprietary tube current and tube voltage modulation techniques (CARE dose and CARE kV). The protocols were compared retrospectively to assess the dose–length product (DLP), aortic radiodensity at the level of the coeliac axis and radiodensity of the portal vein. Results: There were 151 trauma CT examinations during this period. Seventy-eight used the split-bolus protocol. Seventy-one had traditional two-phase imaging. One patient was excluded as they were under the age of 18 years. The radiodensity measurements for the portal vein were significantly higher (p<0.001) in the split-bolus protocol. The mean aortic enhancement in both protocols exceeded 250 HU, although the traditional two-phase protocol gave greater arterial enhancement (p<0.001) than the split-bolus protocol. The split-bolus protocol had a significantly lower (p<0.001) DLP with 43.5% reduction in the mean DLP compared to the traditional protocol. Conclusion: Split-bolus CT imaging offers significant dose reduction for this relatively young population while retaining both arterial and venous enhancement. -- Highlights: •We implemented a split bolus pan-CT protocol for trauma CT. •We compared the radiation dose and vascular enhancement of the split bolus protocol to a traditional two phase protocol. •The split bolus protocol had a 43.5% reduction in mean DLP

  3. Evidence that progression of cells into S-phase is not a prerequisite for recovery between split doses of U.V.-light in synchronized and plateau phase cultures of Ehrlich ascites tumour cells

    International Nuclear Information System (INIS)

    Iliakis, G.; Nuesse, M.

    1982-01-01

    The ability of Ehrlich ascites tumour cells (EAT-cells) to perform split-dose recovery after U.V. exposure was studied with unfed plateau phase as well as with synchronized cells selected from exponentially growing cultures. The cells were kept in balanced salt solution which inhibited the progression of the cells through the cell cycle. The results indicated that split-dose recovery occurred in EAT-cells in all phases of the cell cycle and that progression of the cells into S-phase was not a prerequisite for this type of repair. The second-dose survival curves of G 1 -and S-phase cells showed, 24 hours after the first U.V. exposure, a shoulder width comparable to that of singly irradiated cells. Second-dose survival curves for G 2 -cells showed, after the same time interval, a shoulder width smaller than that for singly exposed cells, presumably due to some cell division. The recovery time constant (t 50 between 4 and 8 hours) increased with increasing U.V. exposure. (author)

  4. Patients with History of Colonoscopy Are Less Likely to Achieve High Quality Preparation After Implementing Split-Dose Bowel Preparation.

    Science.gov (United States)

    Madhoun, M F; Bitar, H; Parava, P; Bashir, M H; Zia, H

    2017-01-01

    Anecdotally, we observed that patients who had previous colonoscopies were less likely to follow newly implemented split-dose bowel preparation (SDBP) instructions. We investigated whether the indication for colonoscopy is an independent factor for achieving high quality bowel preparation among patients asked to follow SDBP. We performed a retrospective study of data from 1478 patients who received outpatient colonoscopies in 2014 (the year of SDBP implementation) at our Veterans Affairs Medical Center. We collected information related to demographics and factors known to affect bowel preparations. Reasons for colonoscopy were dichotomized into surveillance (previous colonoscopy) vs. non-surveillance (positive occult blood test or screening). Bowel preparation quality was scored using the Boston Bowel Preparation Scale (BBPS), and was categorized as either excellent vs. not excellent (BBPS≥7 vs. BBPSquality was excellent in 60% of colonoscopies and adequate in 84% of colonoscopies. Thirty-six percent (535) were surveillance colonoscopies. In multivariate logistic regression analysis, more patients in the non-surveillance group achieved excellent (OR 0.8 ; 95% CI [0.7-0.8], P <0.0001) and adequate (OR 0.8 ; 95% CI [0.7-0.9], P <0.006) bowel preparation than did patients in the surveillance group. Patients with a prior colonoscopy might not follow the split-dose bowel preparation instructions. Educational interventions emphasizing the benefits of SDBP in this group of patients may help ensure compliance and prevent the habitual use of day-before preparations. © Acta Gastro-Enterologica Belgica.

  5. Split-dose recovery in epithelial and vascular-connective tissue of pig skin

    International Nuclear Information System (INIS)

    Peel, D.M.; Hopewell, J.W.; Simmonds, R.H.; Dodd, P.; Meistrich, M.L.

    1984-01-01

    In the first 16 weeks after irradiation, two distinct waves of reaction can be observed in pig skin; the first wave (3-9 weeks) represents the expression of damage to the epithelium while the second is indicative of primary damage to the dermis, mediated through vascular injury. Following β-irradiation with a strontium-90 applicator, a severe epithelial reaction was seen with little subsequent dermal effects. X-rays (250 kV) on the other hand, produced a minimal epithelial response at doses which led to the development of dermal necrosis after 10-16 weeks. Comparison of single doses with two equal doses separated by 24 h produced a D 2 -D 1 value of 7.0 Gy at the doses which produced moist desquamation in 50% of fields (ED 50 ) after strontium-90 irradiation. After X-irradiation comparison of ED 50 doses for the later dermal reaction suggested a D 2 -D 1 value of 4.5 Gy. Over this same dose range of X-rays the D 2 -D 1 value for the first wave epithelial reaction was 3.5 Gy. These values of D 2 -D 1 for epithelial and dermal reactions in pig skin were compared with published data and were examined in relation to the theoretical predictions of a linear quadratic model for tissue target cell survival. The results were broadly in keeping with the productions of such a model. (Auth.)

  6. Linear-quadratic dose kinetics or dose-dependent repair/misrepair

    International Nuclear Information System (INIS)

    Braby, L.A.; Nelson, J.M.

    1992-01-01

    Models for the response of cells exposed to low (LET) linear energy transfer radiation can be grouped into three general types on the basis of assumptions about the nature of the interaction which results in the shoulder of the survival curve. The three forms of interaction are 1) sublethal damage becoming lethal, 2) potentially lethal damage becoming irreparable, and 3) potentially lethal damage ''saturating'' a repair system. The effects that these three forms of interaction would have on the results of specific types of experiments are investigated. Comparisons with experimental results indicate that only the second type is significant in determining the response of typical cultured mammalian cells. (author)

  7. Effect of different intervals of x-ray split doses on shoot production of in vitro derived explants of Gerbera jamesonii Bolus

    Energy Technology Data Exchange (ETDEWEB)

    Walther, F; Sauer, A [Federal Research Centre for Horticultural Plant Breeding, Ahrensburg (Germany)

    1990-01-01

    Full text: Linearity between rising x-ray doses and mutation rate is limited by the simultaneously increasing radiation damage; induced chromosome aberrations eliminate valuable factor mutations. The application of fractionated doses provides the opportunity for repair of a distinct portion of damage. The dose of 30 Gy was fractionated into two identical parts. The periods for repair were 0.5 to 48 hs. The absolute and cumulative number of post-irradiation regenerated axillary shoots on 4 subsequent dates of cutoff were used as parameters to estimate radiosensitivity. From an economical point of view the interval of 4 hs between two dose fractions may be recommended for practice. (author)

  8. Dose escalation without split-course chemoradiation for anal cancer: results of a phase II RTOG study

    International Nuclear Information System (INIS)

    John, Madhu; Pajak, Thomas; Kreig, Richard; Pinover, Wayne H.; Myerson, Robert

    1997-01-01

    PURPOSE: An attempt at radiotherapy (RT) dose escalation (from 45 Gy to 59.6 Gy) in a Radiation Therapy Oncology Group (RTOG) chemoradiation protocol for advanced anal cancers had resulted in an unexpectedly high 1-year colostomy rate (23%) and local failure (The Cancer Journal from Scientific American 2 (4):205-211, 1996). This was felt to be probably secondary to the split course chemoradiation (CR) that was mandated in the protocol. A second phase of this dose escalation study was therefore undertaken without a mandatory split and with an identical RT dose (59.6 Gy) and chemotherapy. MATERIALS AND METHODS: Twenty patients with anal cancers ≥2 cms were treated with a concurrent combination of 59.6 Gy to the pelvis and perineum (1.8 Gy daily, 5 times per week in 33 fractions over 6 (1(2)) weeks) and two cycles of 5 fluorouracil infusion (1000 mg/m 2 over 24 hours for 4 days) and mitomycin C (10 mg/m 2 bolus). A 10 day rest period was allowed only for severe skin reactions. A comparative analysis was made with the 47 patients in the earlier phase of this study who were treated with the identical chemoradiation course but with a mandatory 2-week break at the 36.00 Gy level. RESULTS: Predominant Grade 3 and 4 toxicities in 18 evaluable patients with dermatitis ((14(18)) or 78%), hematologic ((14(18)) or 78%), infection ((3(18)) or 17%) and gastrointestinal ((5(18)) or 28%). There were no fatalities. Nine patients (50%) completed the planned course without a break; 9 others (50%) had their treatments interrupted for a median of 11 days (range 7-19 days) at a median dose of 41.4 Gy (range 32.4 to 48.6 Gy). This compared to (40(47)) patients (85%) who had a 12 day treatment interruption at 36 Gy total dose in a planned break group. One patient had an abdomino-perineal resection (APR) for persistent disease and another for an anal fissure for (2(18)) or 11% 1-year colostomy rate. This was again favorably comparable to 23% 1-year colostomy rate for the earlier group of

  9. Survival of spermatogonial stem cells in the rat after split dose irradiation during LH-RH analogue treatment

    International Nuclear Information System (INIS)

    Kroonenburgh, M.J.P.G. van; Daal, W.A.J. van; Beck, J.L.; Vemer, H.M.; Rolland, R.

    1987-01-01

    A rat model has been created in which a single injection of an LH-RH analogue depot preparation (Zoladex, ICI 118630) produced a temporary interruption of the pituitary-gonadal axis. This effect applied during irradiation was investigated as a possible mechanism to protect the testis from radiation damage. A local testicular irradiation dose of 6.0 Gy was given either as a single dose or as a fractionated (2 x 3.0 Gy) dose at different time intervals ranging from 8 to 72 h. Stem cell survival was measured 11 weeks after irradiation by means of the repopulation index and the number of haploid cells (spermatids) measured by flow cytometry. Serum gonadotrophins and testosterone concentrations were measured to evaluate hormonal recovery. No significant differences were observed between serum concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH) and testosterone and the duration of the fractionation interval. Stem cell survival was higher following fractionated irradiation in comparison with the single dose. For the 8 h interval an increase in recovery ratio was found, amounting to a factor of 5 of the single dose value. The fluctuating pattern of the recovery curves indicated changes in radiosensitivity of stem cells. The combination of hormonal inhibition of spermatogenesis and fractionated irradiation led to a decrease in the absolute numbers of stem cells. However, the stem cell recovery curves were identical to those seen without hormonal inhibition. It was concluded that hormonal pretreatment with Zoladex during split dose irradiation had no protective effect on stem cell survival. 37 refs.; 4 figs

  10. Effects of split fast neutron doses on the liver cells of albino Swiss mice

    International Nuclear Information System (INIS)

    Abdelmeguid, N.; Ramadan, A.A.; El-Khatib, A.M.

    1990-01-01

    The effect of neutron doses from a compact D-T neutron generator on the liver cells of adult male and female albino Swiss mice was investigated. Fast neutrons (14.5 MeV) were delivered to the whole body in a single dose or in two, four, six or eight equal doses separated by 3-day intervals. The lowest dose, 100 rem, was given over an exposure time of 6 hours and was then steadily raised to 912 rem over an exposure time of 48 hours. During exposure the neutron flux was controlled by the activation foil technique. The animals were killed for testing after each irradiation. Histological examination of the hepatocytes with a light microscope showed marked degenerative changes only after the longer irradiation periods (24, 36 and 48 h). Electron microscopy showed cytological (cytoplasmic and nuclear) changes in the hepatocytes after only 12 hours' irradiation. Densitometric scans of electron micrographs of control and 12 h-irradiated livers indicated that the control hepatocyte interphase nucleus contains approximately 72% heterochromatin, while the irradiated nucleus contains only 64% heterochromatin. (author). 13 figs., 1 tab., 18 refs

  11. Adaptive response and split-dose effect of radiation on the survival ...

    Indian Academy of Sciences (India)

    Unknown

    In the present work, we report radioadaptive response in terms of survival of ... Group 4: mice pre-treated with conditioning dose of 0⋅5 Gy ... week in mice exposed to 8 Gy. For mice .... The adaptive response is known to remain for a few hours.

  12. Modulation of DNA polymerase beta-dependent base excision repair in cultured human cells after low dose exposure to arsenite

    International Nuclear Information System (INIS)

    Sykora, Peter; Snow, Elizabeth T.

    2008-01-01

    Base excision repair (BER) is crucial for development and for the repair of endogenous DNA damage. However, unlike nucleotide excision repair, the regulation of BER is not well understood. Arsenic, a well-established human carcinogen, is known to produce oxidative DNA damage, which is repaired primarily by BER, whilst high doses of arsenic can also inhibit DNA repair. However, the mechanism of repair inhibition by arsenic and the steps inhibited are not well defined. To address this question we have investigated the regulation of DNA polymerase β (Pol β) and AP endonuclease (APE1), in response to low, physiologically relevant doses of arsenic. GM847 lung fibroblasts and HaCaT keratinocytes were exposed to sodium arsenite, As(III), and mRNA, protein levels and BER activity were assessed. Both Pol β and APE1 mRNA exhibited significant dose-dependant down regulation at doses of As(III) above 1 μM. However, at lower doses Pol β mRNA and protein levels, and consequently, BER activity were significantly increased. In contrast, APE1 protein levels were only marginally increased by low doses of As(III) and there was no correlation between APE1 and overall BER activity. Enzyme supplementation of nuclear extracts confirmed that Pol β was rate limiting. These changes in BER correlated with overall protection against sunlight UV-induced toxicity at low doses of As(III) and produced synergistic toxicity at high doses. The results provide evidence that changes in BER due to low doses of arsenic could contribute to a non-linear, threshold dose response for arsenic carcinogenesis

  13. Mutation induction in haploid yeast after split-dose radiation exposure. II. Combination of UV-irradiation and X-rays.

    Science.gov (United States)

    Keller, B; Zölzer, F; Kiefer, J

    2004-01-01

    Split-dose protocols can be used to investigate the kinetics of recovery from radiation damage and to elucidate the mechanisms of cell inactivation and mutation induction. In this study, a haploid strain of the yeast, Saccharomyces cerevisiae, wild-type with regard to radiation sensitivity, was irradiated with 254-nm ultraviolet (UV) light and then exposed to X-rays after incubation for 0-6 hr. The cells were incubated either on nutrient medium or salt agar between the treatments. Loss of reproductive ability and mutation to canavanine resistance were measured. When the X-ray exposure immediately followed UV-irradiation, the X-ray survival curves had the same slope irrespective of the pretreatment, while the X-ray mutation induction curves were changed from linear to linear quadratic with increasing UV fluence. Incubations up to about 3 hr on nutrient medium between the treatments led to synergism with respect to cell inactivation and antagonism with respect to mutation, but after 4-6 hr the two treatments acted independently. Incubation on salt agar did not cause any change in the survival curves, but there was a strong suppression of X-ray-induced mutation with increasing UV fluence. On the basis of these results, we suggest that mutation after combined UV and X-ray exposure is affected not only by the induction and suppression of DNA repair processes, but also by radiation-induced modifications of cell-cycle progression and changes in the expression of the mutant phenotype. Copyright 2004 Wiley-Liss, Inc.

  14. Effects of single and split doses of cobalt-60 gamma rays and 14 MeV neutrons on mouse stem cell spermatogonia.

    Science.gov (United States)

    Hacker-Klom, U B; Köhnlein, W; Göhde, W

    2000-12-01

    The long-term effects of ionizing radiation on male gonads may be the result of damage to spermatogonial stem cells. Doses of 10 cGy to 15 Gy (60)Co gamma rays or 10 cGy to 7 Gy 14 MeV neutrons were given to NMRI mice as single or split doses separated by a 24-h interval. The ratios of haploid spermatids/2c cells and the coefficients of variation of DNA histogram peaks as measures of both the cytocidal and the clastogenic actions of radiation were analyzed by DNA flow cytometry after DAPI staining. The coefficient of variation is not only a statistical examination of the data but is also used here as a measure of residual damage to DNA (i.e. a biological dosimeter). Testicular histology was examined in parallel. At 70 days after irradiation, the relative biological effectiveness for neutrons at 50% survival of spermatogonial stem cells was 3.6 for single doses and 2.8 for split doses. The average coefficient of variation of unirradiated controls of elongated spermatids was doubled when stem cells were irradiated with single doses of approximately 14 Gy (60)Co gamma rays or 3 Gy neutrons and observed 70 days later. Split doses of (60)Co gamma rays were more effective than single doses, doubling DNA dispersion at 7 Gy. No fractionation effect was found with neutrons with coefficients of variation.

  15. Chronic low-dose ultraviolet-induced mutagenesis in nucleotide excision repair-deficient cells.

    Science.gov (United States)

    Haruta, Nami; Kubota, Yoshino; Hishida, Takashi

    2012-09-01

    UV radiation induces two major types of DNA lesions, cyclobutane pyrimidine dimers (CPDs) and 6-4 pyrimidine-pyrimidine photoproducts, which are both primarily repaired by nucleotide excision repair (NER). Here, we investigated how chronic low-dose UV (CLUV)-induced mutagenesis occurs in rad14Δ NER-deficient yeast cells, which lack the yeast orthologue of human xeroderma pigmentosum A (XPA). The results show that rad14Δ cells have a marked increase in CLUV-induced mutations, most of which are C→T transitions in the template strand for transcription. Unexpectedly, many of the CLUV-induced C→T mutations in rad14Δ cells are dependent on translesion synthesis (TLS) DNA polymerase η, encoded by RAD30, despite its previously established role in error-free TLS. Furthermore, we demonstrate that deamination of cytosine-containing CPDs contributes to CLUV-induced mutagenesis. Taken together, these results uncover a novel role for Polη in the induction of C→T transitions through deamination of cytosine-containing CPDs in CLUV-exposed NER deficient cells. More generally, our data suggest that Polη can act as both an error-free and a mutagenic DNA polymerase, depending on whether the NER pathway is available to efficiently repair damaged templates.

  16. Electiveness of photorepair, influence of dark-repair on shape of dose-response curves, and high-dose decline, in UV-induced colour mutations of Serratia

    International Nuclear Information System (INIS)

    Kaplan, R.W.

    1978-01-01

    Strain CV of Serratia marcescens mutates by UV with high frequency to 3 groups of mutants (w, h, s) differing in colour from the red wild-type. The mutational dose-response curve has a curvature corresponding to about 3 hits. It reaches a peak and declines at high doses. Inactivation curves have a broad shoulder and mostly, but not always, a break to a lesser slope at UV doses near the peak of mutations. Photo reactivation (PR) gives a dose reduction of about 2 for both inactivation and mutation including the break and peak. The dose curve with PR for w-mutations shows 1 hit-, the other types 2-hit curvature leading to a change of mutation spectrum with dose due to PR. The UV-sensitive mutant uvs21 of CV has a survival curve with a small shoulder and a long upward concavity without a break, and the mutation curve is of the one-hit type without a peak and decline. PR gives a dose reduction of 12 for inactivation and of 7.5 for mutation. The 3-hit mutation curve of CV is interpreted by assuming that 2 further hits are required to protect the 1-hit pre-mutations from being abolished by the repair lacking in uvs21. UV induction of SOS repair cannot be responsible for the 3-hit curvature because UVR of phages and induction of prophage are already saturated at rather low doses. As high-dose decline is not observed in uvs21, possibly the non-mutagenic repair lacking from uvs21 interferes with the mutation finishing processes at high doses in the repair-proficient strain CV. However, UV induction of this interference cannot be a one-hit process but requires a very large number of hits. (Auth.)

  17. Radiobiological basis of total body irradiation with different dose rate and fractionation: repair capacity of hemopoietic cells

    International Nuclear Information System (INIS)

    Song, C.W.; Kim, T.H.; Khan, F.M.; Kersey, J.H.; Levitt, S.H.

    1981-01-01

    Total body irradiation (TBI) followed by bone marrow transplantation is being used in the treatment of malignant or non-malignant hemopoietic disorders. It has been believed that the ability of hemopoietic cells to repair sublethal radiation damage is negligible. Therefore, several schools of investigators suggested that TBI in a single exposure at extremely low dose rate (5 rad/min) over several hours, or in several fractions in 2-3 days, should yield a higher therapeutic gain, as compared with a single exposure at a high dose rate (26 rad/min). We reviewed the existing data in the literature, in particular, the response of hemopoietic cells to fractionated doses of irradiation and found that the repair capacity of both malignant and non-malignant hemopoietic cells might be greater than has been thought. It is concluded that we should not underestimate the ability of hemopoietic cells to repair sublethal radiation damage in using TBI

  18. Role of repair saturation in the response of plateau-phase Chinese hamster ovary cells

    International Nuclear Information System (INIS)

    Braby, L.A.; Nelson, J.M.; Metting, N.F.

    1987-01-01

    Two repair rates are seen in split-dose experiments on starved plateau-phase CHO cells. It has been assumed that this indicates two different processes repairing two distinct types of sublethal damage. However results of experiments at different dose levels are not consistent with models that assume that the damage is entirely sublethal. Another hypothesis that has been considered is the saturation of a repair mechanism having a limited pool of repair enzymes. Such saturation phenomena have been observed in biochemical repair studies and have thus formed the basis for a model of cellular response, which was shown to be capable of producing dose response curves in good agreement with experimental observations. This model can be extended to account for both dose-rate and split-dose effects

  19. Quantitative assessment of the dose-response of alkylating agents in DNA repair proficient and deficient ames tester strains.

    Science.gov (United States)

    Tang, Leilei; Guérard, Melanie; Zeller, Andreas

    2014-01-01

    Mutagenic and clastogenic effects of some DNA damaging agents such as methyl methanesulfonate (MMS) and ethyl methanesulfonate (EMS) have been demonstrated to exhibit a nonlinear or even "thresholded" dose-response in vitro and in vivo. DNA repair seems to be mainly responsible for these thresholds. To this end, we assessed several mutagenic alkylators in the Ames test with four different strains of Salmonella typhimurium: the alkyl transferases proficient strain TA1535 (Ogt+/Ada+), as well as the alkyl transferases deficient strains YG7100 (Ogt+/Ada-), YG7104 (Ogt-/Ada+) and YG7108 (Ogt-/Ada-). The known genotoxins EMS, MMS, temozolomide (TMZ), ethylnitrosourea (ENU) and methylnitrosourea (MNU) were tested in as many as 22 concentration levels. Dose-response curves were statistically fitted by the PROAST benchmark dose model and the Lutz-Lutz "hockeystick" model. These dose-response curves suggest efficient DNA-repair for lesions inflicted by all agents in strain TA1535. In the absence of Ogt, Ada is predominantly repairing methylations but not ethylations. It is concluded that the capacity of alkyl-transferases to successfully repair DNA lesions up to certain dose levels contributes to genotoxicity thresholds. Copyright © 2013 Wiley Periodicals, Inc.

  20. Nitrogen split dose fertilization, plant age and frost effects on phytochemical content and sensory properties of curly kale (Brassica oleracea L. var. sabellica).

    Science.gov (United States)

    Groenbaek, Marie; Jensen, Sidsel; Neugart, Susanne; Schreiner, Monika; Kidmose, Ulla; Kristensen, Hanne L

    2016-04-15

    We investigated how concentrations of sensory relevant compounds: glucosinolates (GLSs), flavonoid glycosides, hydroxycinnamic acid derivatives and sugars in kale responded to split dose and reduced nitrogen (N) fertilization, plant age and controlled frost exposure. In addition, frost effects on sensory properties combined with N supply were assessed. Seventeen week old kale plants showed decreased aliphatic GLSs at split dose N fertilization; whereas reduced N increased aliphatic and total GLSs. Ontogenetic effects were demonstrated for all compounds: sugars, aliphatic and total GLSs increased throughout plant development, whereas kaempferol and total flavonoid glycosides showed higher concentrations in 13 week old plants. Controlled frost exposure altered sugar composition slightly, but not GLSs or flavonoid glycosides. Reduced N supply resulted in less bitterness, astringency and pungent aroma, whereas frost exposure mainly influenced aroma and texture. N treatment explained most of the sensory variation. Producers should not rely on frost only to obtain altered sensory properties. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Repair of human DNA in molecules that replicate or remain unreplicated following ultraviolet irradiation

    International Nuclear Information System (INIS)

    Waters, R.

    1980-01-01

    The extent of DNA replication, the incidence of uv induced pyrimidine dimers and the repair replication observed after their excision was monitored in human fibroblasts uv irradiated with single or split uv doses. The excision repair processes were measured in molecules that remained unreplicated or in those that replicated after the latter uv irradiation. Less DNA replication was observed after a split as opposed to single uv irradiation. Furthermore, a split dose did not modify the excision parameters measured after a single irradiation, regardless of whether the DNA had replicated or not

  2. Molecular dosimetry of chemical mutagens: measurement of molecular dose and DNA repair germ cells

    International Nuclear Information System (INIS)

    Sega, G.A.

    1975-01-01

    Molecular dosimetry in the germ cells of male mice is reviewed with regard to in vivo alkylation of sperm heads, in vivo alkylation of sperm DNA, and possible alkylation of sperm protamine. DNA repair in male germ cells is reviewed with regard to basic design of experiments, DNA repair in various stages of spermatogenesis, effect of protamine on DNA repair following treatment with EMS or x radiation, and induction of DNA repair by methyl methanesulfonate, propyl methanesulfonate, and isopropyl methanesulfonate

  3. Quantification of rat retinal growth and vascular population changes after single and split doses of proton irradiation: translational study using stereology methods

    Science.gov (United States)

    Mao, Xiao W.; Archambeau, John O.; Kubinova, Lucie; Boyle, Soames; Petersen, Georgia; Grove, Roger; Nelson, G. A. (Principal Investigator)

    2003-01-01

    This study quantified architectural and population changes in the rat retinal vasculature after proton irradiation using stereology. A 100 MeV conformal proton beam delivered 8, 14, 20 and 28 Gy as single and split doses to the whole eye. The vascular networks were prepared from retinal digests. Stereological methods were used to obtain the area of the retina and unbiased estimates of microvessel/artery/vein endothelial, pericyte and smooth muscle population, and vessel length. The retinal area increased progressively in the unirradiated, age-matched controls and in the retinas irradiated with 8 and 14 Gy, indicating uniform progressive retinal growth. No growth occurred after 20 and 28 Gy. Regression analysis of total endothelial cell number in all vessels (arteries, veins and capillaries) after irradiation documented a progressive time- and dose-dependent cell loss occurring over 15 to 24 months. The difference from controls was significant (Ppopulations after split doses. At 10 Gy, the rate of endothelial cell loss, a dose parameter used to characterize the time- and dose-dependent loss of the endothelial population, was doubled.

  4. Optimal preparation-to-colonoscopy interval in split-dose PEG bowel preparation determines satisfactory bowel preparation quality: an observational prospective study.

    Science.gov (United States)

    Seo, Eun Hee; Kim, Tae Oh; Park, Min Jae; Joo, Hee Rin; Heo, Nae Yun; Park, Jongha; Park, Seung Ha; Yang, Sung Yeon; Moon, Young Soo

    2012-03-01

    Several factors influence bowel preparation quality. Recent studies have indicated that the time interval between bowel preparation and the start of colonoscopy is also important in determining bowel preparation quality. To evaluate the influence of the preparation-to-colonoscopy (PC) interval (the interval of time between the last polyethylene glycol dose ingestion and the start of the colonoscopy) on bowel preparation quality in the split-dose method for colonoscopy. Prospective observational study. University medical center. A total of 366 consecutive outpatients undergoing colonoscopy. Split-dose bowel preparation and colonoscopy. The quality of bowel preparation was assessed by using the Ottawa Bowel Preparation Scale according to the PC interval, and other factors that might influence bowel preparation quality were analyzed. Colonoscopies with a PC interval of 3 to 5 hours had the best bowel preparation quality score in the whole, right, mid, and rectosigmoid colon according to the Ottawa Bowel Preparation Scale. In multivariate analysis, the PC interval (odds ratio [OR] 1.85; 95% CI, 1.18-2.86), the amount of PEG ingested (OR 4.34; 95% CI, 1.08-16.66), and compliance with diet instructions (OR 2.22l 95% CI, 1.33-3.70) were significant contributors to satisfactory bowel preparation. Nonrandomized controlled, single-center trial. The optimal time interval between the last dose of the agent and the start of colonoscopy is one of the important factors to determine satisfactory bowel preparation quality in split-dose polyethylene glycol bowel preparation. Copyright © 2012 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.

  5. Embryo splitting

    Directory of Open Access Journals (Sweden)

    Karl Illmensee

    2010-04-01

    Full Text Available Mammalian embryo splitting has successfully been established in farm animals. Embryo splitting is safely and efficiently used for assisted reproduction in several livestock species. In the mouse, efficient embryo splitting as well as single blastomere cloning have been developed in this animal system. In nonhuman primates embryo splitting has resulted in several pregnancies. Human embryo splitting has been reported recently. Microsurgical embryo splitting under Institutional Review Board approval has been carried out to determine its efficiency for blastocyst development. Embryo splitting at the 6–8 cell stage provided a much higher developmental efficiency compared to splitting at the 2–5 cell stage. Embryo splitting may be advantageous for providing additional embryos to be cryopreserved and for patients with low response to hormonal stimulation in assisted reproduction programs. Social and ethical issues concerning embryo splitting are included regarding ethics committee guidelines. Prognostic perspectives are presented for human embryo splitting in reproductive medicine.

  6. Influence of phosphorus and the application of split doses of nitrogen on the nitrogen fertilizer use efficiency of a potato crop

    International Nuclear Information System (INIS)

    Bastidas, O.G.; Urquiaga, S.

    1988-01-01

    The study was performed in an inceptisol at the ''San Jorge'' experimental station (altitude 2.900 m), Bogota, Colombia. The influence of phosphate and the application of split doses of nitrogen on the nitrogen fertilizer use efficiency of a potato crop. (Solanum tuberosum, L.) cv Tequendama, was evaluated. The phosphate was applied at levels of 100, 150 and 200 Kg P 2 O 5 ha -1 in the form of triple super phosphate. The nitrogen (100 Kg N. ha -1 ) was applied in split doses at seeding and 60 days after emergence (DAE) in the following proportions: 1/3: 2/3 or 1/2. The N source used was Urea labelled with 1.5 atom % 15 N excess. The results showed that: a) The maximum tuber yield (41 t.ha -1 ) was experience with 100 Kg P 2 O 5 Ha -1 and this was significantly higher than a zero phosphate control (24t. ha -1 ) even though the soluble soil phosphorus (Bray II) was high. b) The phosphate favoured the productivity of the crop and increased the N fertilizer use efficiency (% FUE) from 28 to 51%.c). The different splitting of the N fertilizer application had no detectable effect on yield % FUE. d) The tubers represented 76% of the total dry matter and contained 63% of the total nitrogen and fertilizer N accumulated by the crop

  7. A UV-Induced Genetic Network Links the RSC Complex to Nucleotide Excision Repair and Shows Dose-Dependent Rewiring

    Directory of Open Access Journals (Sweden)

    Rohith Srivas

    2013-12-01

    Full Text Available Efficient repair of UV-induced DNA damage requires the precise coordination of nucleotide excision repair (NER with numerous other biological processes. To map this crosstalk, we generated a differential genetic interaction map centered on quantitative growth measurements of >45,000 double mutants before and after different doses of UV radiation. Integration of genetic data with physical interaction networks identified a global map of 89 UV-induced functional interactions among 62 protein complexes, including a number of links between the RSC complex and several NER factors. We show that RSC is recruited to both silenced and transcribed loci following UV damage where it facilitates efficient repair by promoting nucleosome remodeling. Finally, a comparison of the response to high versus low levels of UV shows that the degree of genetic rewiring correlates with dose of UV and reveals a network of dose-specific interactions. This study makes available a large resource of UV-induced interactions, and it illustrates a methodology for identifying dose-dependent interactions based on quantitative shifts in genetic networks.

  8. Radiosensitivity of Nicotiana protoplasts. Action on cell; cycle effects of low dose and fractionated irradiations; biological repair

    International Nuclear Information System (INIS)

    Magnien, E.

    1981-10-01

    Leaf protoplasts of Nicotiana plumbaginifolia and Nicotiana sylvestris demonstrate five main qualities: they can be maintained as haploid lines; they constitute starting populations with a remarkable cytological homogeneity; they show a transient initial lag-phase; they yield very high plating efficiencies and retain permanently a complete differentiation capacity; being derived of a cell wall, they appear well adapted for fusion experiments or enzymatic dosages. The resumption of mitotic activity was followed by cytophotometric measurements, labelling experiments, nuclear sizing and enzymatic assays. The action of 5 Gy gamma-ray irradiations delayed entrance in the S-phase, provoked an otherwise not verified dependency between transcription, translation and protein synthesis, increased nuclear volumes in the G2-phase, and slightly stimulated the activity of a repair enzyme. The plating efficiency was a sensitive end-point which allowed the evaluation of the biological effectiveness of low to medium radiation-doses after gamma-ray and fast neutron irradiations. The neutron dose-RBE relationship increased from 3 to 25 when the dose decreased from 5 Gy to 5 mGy. When fractionated into low single doses only, a neutron dose of 300 mGy markedly increased its biological effectiveness: this phenomenon could not be explained by cell progression, and necessitated additional hypotheses involving other mechanisms in the specific action of low radiation doses. Radiation-induced UDS was measured in presence of aphidicolin. A beta-like DNA-polymerase was shown to be definitely involved in nuclear repair synthesis [fr

  9. Impact of DNA repair on the dose-response of colorectal cancer formation induced by dietary carcinogens.

    Science.gov (United States)

    Fahrer, Jörg; Kaina, Bernd

    2017-08-01

    Colorectal cancer (CRC) is one of the most frequently diagnosed cancers, which is causally linked to dietary habits, notably the intake of processed and red meat. Processed and red meat contain dietary carcinogens, including heterocyclic aromatic amines (HCAs) and N-nitroso compounds (NOC). NOC are agents that induce various N-methylated DNA adducts and O 6 -methylguanine (O 6 -MeG), which are removed by base excision repair (BER) and O 6 -methylguanine-DNA methyltransferase (MGMT), respectively. HCAs such as the highly mutagenic 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) cause bulky DNA adducts, which are removed from DNA by nucleotide excision repair (NER). Both O 6 -MeG and HCA-induced DNA adducts are linked to the occurrence of KRAS and APC mutations in colorectal tumors of rodents and humans, thereby driving CRC initiation and progression. In this review, we focus on DNA repair pathways removing DNA lesions induced by NOC and HCA and assess their role in protecting against mutagenicity and carcinogenicity in the large intestine. We further discuss the impact of DNA repair on the dose-response relationship in colorectal carcinogenesis in view of recent studies, demonstrating the existence of 'no effect' point of departures (PoDs), i.e. thresholds for genotoxicity and carcinogenicity. The available data support the threshold concept for NOC with DNA repair being causally involved. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Effect of cell cycle stage, dose rate and repair of sublethal damage of radiation-induced apoptosis in F9 teratocarcinoma cells

    International Nuclear Information System (INIS)

    Langley, R.E.; Quartuccio, S.G.; Kennealey, P.T.

    1995-01-01

    There are at least two different models of cell death after treatment with ionizing radiation. The first is a failure to undergo sustained cell division despite metabolic survival, and we refer to this end point as open-quotes classical reproductive cell death.close quotes The second is a process that results in loss of cell integrity. This second category includes cellular necrosis as well as apoptosis. Earlier studies in our laboratory showed that the predominant mechanism of cell death for irradiated F9 cell is apoptosis, and there is no indication that these cells die by necrosis. We have therefore used cells of this cell line to reassess basic radiobiological principles with respect to apoptosis. Classical reproductive cell death was determined by staining colonies derived from irradiated cells and scoring colonies of less than 50 cells as reproductively dead and colonies of more than 50 cells as survivors. Cells that failed to produce either type of colony (detached from the plate or disintegrated) were scored as having undergone apoptosis. Using these criteria we found that the fraction of the radiation-killed F9 cells that died by apoptosis did not vary when cells were irradiated at different stages of the cell cycle despite large variations in overall survival. This suggests that the factors that influence radiation sensitivity throughout the cell cycle have an equal impact on apoptosis and classical reproductive cell death. There was no difference in cell survival between split doses and single doses of X rays, suggesting that sublethal damage repair is not a factor in radiation-induced apoptosis of F9 cells. Apoptosis was not affected by changes in dose rate in the range of 0.038-4.96 Gy/min. 48 refs., 6 figs., 1 tab

  11. A limitation of the split-dose method for evaluating rCBF changes using {sup 99m}Tc-ECD and SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Odano, Ikuo; Takahashi, Makoto; Noguchi, Eikichi; Ohtaki, Hiro; Shibaki, Mitsurou; Kasahara, Tosifumi; Hatano, Masayoshi [Niigata Univ. (Japan). School of Medicine; Ohkubo, Masaki

    1997-05-01

    The purpose of the study is to validate the split-dose method corrected with dose ratio of {sup 99m}Tc-ECD for brain perfusion scan. A dose of 600 MBq of {sup 99m}Tc-ECD was divided into two with various dose ratios from 1 : 1 to 1 : 4, and injected to eleven patients with various cerebral diseases. A lesser dose of {sup 99m}Tc-ECD was injected under a control state for the first SPECT scan, and 15 min SPECT scan was performed 10 min after injection with a triple-head high resolution gamma camera. After the scan, the other dose of {sup 99m}Tc-ECD was injected under the same control state and the second SPECT scan was performed as same as above. A ratio of the activity of the first scan to the net activity of the second scan corrected by dose ratio, defined as K, was measured in brain regions of each subject. Expected value of K was 1, but the value was distributed with large variations in each subject. The mean % error of the K value was 10.4{+-}4.9%. Hence it is considered that activity changes by more than 20% from the control values should be required to detect a significant rCBF change in an activation SPECT study. Then, we proposed a new method in which the activity of both two SPECT scans was normalized by cerebellar or occipital activity and compared. The ratio obtained by the proposed method came closer to 1 with less variations and with less mean % error in comparison with those of K value obtained by the dose-correction method. Although the proposed method has a limitation in the use of an activation study loaded with Diamox, it may be useful to evaluate an alteration of rCBF in the study such as postural testing or finger-moving test. (author)

  12. A limitation of the split-dose method for evaluating rCBF changes using 99mTc-ECD and SPECT

    International Nuclear Information System (INIS)

    Odano, Ikuo; Takahashi, Makoto; Noguchi, Eikichi; Ohtaki, Hiro; Shibaki, Mitsurou; Kasahara, Tosifumi; Hatano, Masayoshi; Ohkubo, Masaki.

    1997-01-01

    The purpose of the study is to validate the split-dose method corrected with dose ratio of 99m Tc-ECD for brain perfusion scan. A dose of 600 MBq of 99m Tc-ECD was divided into two with various dose ratios from 1 : 1 to 1 : 4, and injected to eleven patients with various cerebral diseases. A lesser dose of 99m Tc-ECD was injected under a control state for the first SPECT scan, and 15 min SPECT scan was performed 10 min after injection with a triple-head high resolution gamma camera. After the scan, the other dose of 99m Tc-ECD was injected under the same control state and the second SPECT scan was performed as same as above. A ratio of the activity of the first scan to the net activity of the second scan corrected by dose ratio, defined as K, was measured in brain regions of each subject. Expected value of K was 1, but the value was distributed with large variations in each subject. The mean % error of the K value was 10.4±4.9%. Hence it is considered that activity changes by more than 20% from the control values should be required to detect a significant rCBF change in an activation SPECT study. Then, we proposed a new method in which the activity of both two SPECT scans was normalized by cerebellar or occipital activity and compared. The ratio obtained by the proposed method came closer to 1 with less variations and with less mean % error in comparison with those of K value obtained by the dose-correction method. Although the proposed method has a limitation in the use of an activation study loaded with Diamox, it may be useful to evaluate an alteration of rCBF in the study such as postural testing or finger-moving test. (author)

  13. Repair of pyrimidine dimers in nuclear and mitochondrial DNA of yeast irradiated with low doses of ultraviolet light

    Energy Technology Data Exchange (ETDEWEB)

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

    1975-01-01

    The repair of damage induced by ultraviolet light has been examined in both the nuclear and mitochondrial DNA of the yeast Saccharomyces cerevisiae. The sensitive assay used in this study is based on the capacity of the bacteriophage T4 u.v. endonuclease to produce single-strand breaks in DNA that contains pyrimidine dimers, thus permitting the use of low fluences (doses) of u.v. The results demonstrate that virtually all of the dimers induced in the nuclear DNA of a repair-proficient strain (RAD+) are removed following dark incubation for four hours in growth medium. In contrast, the dimers induced in mitochondrial DNA by the same u.v. fluence are retained under the same conditions. In the excision-deficient mutant, rad1-2, no evidence was obtained for removal of pyrimidine dimers from nuclear DNA. Photoreactivation of both RAD + and rad1-2 cultures resulted in decreases of dimers from both nuclear and mitochondrial DNA. It is concluded that an excision-repair mechanism operates on nuclear but not mitochondrial DNA in repair-proficient yeast, and that the rad1-2 mutant is defective in this process.

  14. ALARA review of the maintenance and repair jobs of repetitive high radiation dose at Kori Unit 3 and 4

    International Nuclear Information System (INIS)

    Cho, Y.H.; Moon, J.H.; Kang, C.S.; Lee, J.S.; Lee, D.H.

    2003-01-01

    The policy of maintaining occupational radiation dose (ORD) as low as reasonably achievable (ALARA) requires the effective reduction of ORD in the phases of design as well as operation of nuclear power plants. It has been identified that a predominant portion of ORD arises during maintenance and repair operations at nuclear power plants. The cost-effective reduction of ORD cannot be achieved without a comprehensive analysis of accumulated ORD data of existing nuclear power plants. To identify the jobs of repetitive high ORD, the ORD data of Kori Units 3 and 4 over 10-year period from 1986 to 1995 were compiled into the PC-based ORD database program. As the radiation job classification structure, 26 main jobs are considered, most of which are further subdivided into detailed jobs. According to the order of the collective dose values for 26 main jobs, 10 jobs of high collective dose are identified. As an ALARA review, then, top 10 jobs of high collective dose are statistically analyzed with regard to 1) dose rate, 2) crew number and 3) job frequency that are the factors determining the collective dose for the radiation job of interest. Through the ALARA review, main reasons causing to high collective dose values are identified as follows. The high collective dose of RCP maintenance job is mainly due to the large crew number and the high job frequency. The characteristics of refueling job are similar to those of RCP maintenance job. However, the high collective doses of SG-related jobs such as S/G nozzle dam job, S/G man-way job and S/G tube maintenance job are mainly due to high radiation dose rate. (author)

  15. A generalised formulation of the 'incomplete-repair' model for cell survival and tissue response to fractionated low dose-rate irradiation

    International Nuclear Information System (INIS)

    Nilsson, P.; Joiner, M.C.

    1990-01-01

    A generalized equation for cell survival or tissue effects after fractionated low dose-rate irradiations, when there is incomplete repair between fractions and significant repair during fractions, is derived in terms of the h- and g-functions of the 'incomplete-repair' (IR) model. The model is critically dependent on α/β, repair half-time, treatment time and interfraction interval, and should therefore be regarded primarily as a tool for the analysis of fractionation and dose-rate effects in carefully designed radiobiological experiments, although it should also be useful in exploring, in a general way, the feasibility of clinical treatment protocols using fractionated low dose-rate treatments. (author)

  16. Development of quantification analysis software for measuring regional cerebral blood flow by the modified split-dose method with 123I-IMP before and after acetazolamide loading

    International Nuclear Information System (INIS)

    Nagaki, Akio; Kobara, Kouichi; Matsutomo, Norikazu

    2003-01-01

    We developed a quantification analysis software program for measuring regional cerebral blood flow (rCBF) at rest and under acetazolamide (ACZ) stress by the modified split-dose (MSD) method with iodine-123 N-isopropyl-p-iodoamphetamine (IMP) and compared the rCBF values measured by the MSD method and by the split dose 123 I-IMP SPECT (SD) method requiring one continuous withdrawal of arterial blood. Since the MSD method allows the input of two arterial blood sampling parameter values, the background subtraction procedure for obtaining ACZ-induced images in the MSD method is not identical to the procedure in the SD method. With our software program for rCBF quantification, the resting rCBF values determined by the MSD method were closely correlated with the values measured by the SD method (r=0.94), and there was also a good correlation between the ACZ-induced rCBF values obtained by the MSD method and by the SD method (r=0.81). The increase in rCBF under ACZ stress was estimated to be approximately 26% by the SD method and 38% by the MSD method, suggesting that the MSD method tends to overestimate the increase in rCBF under ACZ stress in comparison with the SD method, but the variability of the rCBF values at rest and during ACZ stress analyzed by the MSD method was smaller than the variability with the SD method. Further clinical studies are required to validate our rCBF quantification analysis program for the MSD method. (author)

  17. DNA mismatch repair protein MSH2 dictates cellular survival in response to low dose radiation in endometrial carcinoma cells.

    LENUS (Irish Health Repository)

    Martin, Lynn M

    2013-07-10

    DNA repair and G2-phase cell cycle checkpoint responses are involved in the manifestation of hyper-radiosensitivity (HRS). The low-dose radioresponse of MSH2 isogenic endometrial carcinoma cell lines was examined. Defects in cell cycle checkpoint activation and the DNA damage response in irradiated cells (0.2 Gy) were evaluated. HRS was expressed solely in MSH2+ cells and was associated with efficient activation of the early G2-phase cell cycle checkpoint. Maintenance of the arrest was associated with persistent MRE11, γH2AX, RAD51 foci at 2 h after irradiation. Persistent MRE11 and RAD51 foci were also evident 24 h after 0.2 Gy. MSH2 significantly enhances cell radiosensitivity to low dose IR.

  18. Use of high-dose erythropoietin for repair after injury: A comparison of outcomes in heart and kidney.

    Science.gov (United States)

    Gobe, Glenda C; Morais, Christudas; Vesey, David A; Johnson, David W

    2013-07-01

    There is a need to define the exact benefits and contraindications of use of high-dose recombinant human erythropoietin (EPO) for its non-hematopoietic function as a cytokine that enhances tissue repair after injury. This review compares the outcomes from use of EPO in the injured heart and kidney, two organs that are thought, traditionally, to have intrinsically-different repair mechanisms. Directory of Open Access Journals (DOAJ), Google Scholar, Pubmed (NLM), LISTA (EBSCO) and Web of Science have been searched. Ongoing work by us on EPO protection of ischemia-reperfusion-injured kidneys indicated, first, that EPO acutely enhanced kidney repair via anti-apoptotic, pro-regenerative mechanisms, and second, that EPO may promote chronic fibrosis in the long term. Work by others on the ischaemia-injured heart has also indicated that EPO promotes repair. Although myocardial infarcts are made up mostly of necrotic tissue, many publications state EPO is anti-apoptotic in the heart, as well as promoting healing via cell differentiation and stimulation of granulation tissue. In the case of the heart, promotion of fibrosis may be advantageous where an infarct has destroyed a zone of cardiomyocytes, but if EPO stimulates progressive fibrosis in the heart, this may promote cardiac failure. A major concern in relation to the use of EPO in a cytoprotective role is its stimulation of long-term inflammation and fibrosis. EPO usage for cytoprotection is undoubtedly advantageous, but it may need to be offset with an anti-inflammatory agent in some organs, like kidney and heart, where progression to chronic fibrosis after acute injury is often recorded.

  19. High doses of ionizing radiation on bone repair: is there effect outside the irradiated site?

    Science.gov (United States)

    Rocha, Flaviana Soares; Dias, Pâmella Coelho; Limirio, Pedro Henrique Justino Oliveira; Lara, Vitor Carvalho; Batista, Jonas Dantas; Dechichi, Paula

    2017-03-01

    Local ionizing radiation causes damage to bone metabolism, it reduces blood supply and cellularity over time. Recent studies indicate that radiation promotes biological response outside the treatment field. The aim of this study was to investigate the effects of ionizing radiation on bone repair outside the irradiated field. Ten healthy male Wistar rats were used; and five animals were submitted to radiotherapy on the left femur. After 4 weeks, in all animals were created bone defects in the right and left femurs. Seven days after surgery, animals were euthanized. The femurs were removed and randomly divided into 3 groups (n=5): Control (C) (right femur of the non-irradiated animals); Local ionizing radiation (IR) (left femur of the irradiated animals); Contralateral ionizing radiation (CIR) (right femur of the irradiated animals). The femurs were processed and embedded in paraffin; and bone histologic sections were evaluated to quantify the bone neoformation. Histomorphometric analysis showed that there was no significant difference between groups C (24.6±7.04) and CIR (25.3±4.31); and IR group not showed bone neoformation. The results suggest that ionizing radiation affects bone repair, but does not interfere in bone repair distant from the primary irradiated site. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Specificity of DNA repair in plants exposed at low dose-rate

    International Nuclear Information System (INIS)

    Semov, A.B.; Ptitsina, S.N.; Shevchenko, V.A.

    1997-01-01

    Intensity of gamma-ray induced unscheduled DNA synthesis (UDS) as well as yield and repair of single-strand DNA breaks (SSB) were investigated in control and exposed higher plant populations. Populations of V. cracca have been chronically irradiating by 90 Sr-beta-particles due to Kyshtym accident (South Ural) or have been growing on the uranium-miner tails (alpha-irradiation). In former case increased radioresistance was revealed (the phenomenon previously called radio-adaptation and that probably has something in common with adaptive response). This radioresistance correlates with higher intensity of UDS. On the basis of experiments with specific inhibitors of alpha- and beta- like DNA polymerases (aphidicolin, di-deoxy-thymidine) and protein synthesis (cycloheximide) it was assumed that the enhanced UDS in radioresistant population is an partially inducible process in which both DNA polymerases take part. In control population UDS is not inducible and totally inhibited by ddT. Differences in induction and repair of gamma-ray induced SSB between control and radioresistant populations were not registered. In case of chronic alpha-irradiation increased radiosensitivity and slightly decreased UDS were found. In this population and in some populations from Chernobyl vicinity, analyzed in 1986-1991, higher yield of SSB was registered but repair of SSB was not differ from control ones. (authors)

  1. Cellular and molecular repair of X-ray-induced damage: dependence on oxygen tension and nutritional status

    International Nuclear Information System (INIS)

    Spiro, I.J.; Kennedy, K.A.; Stickler, R.; Ling, C.C.

    1985-01-01

    Cellular and molecular repair was studied at 23 0 C using split-dose recovery and alkaline elution techniques, respectively, as a function of cellular oxygen and nutrient conditions. Hypoxic cells in full medium showed a partial reduction in the level of sublethal damage (SLD) repair relative to aerated cells; the respective repair kinetics were similar with a common repair half-time of 30 min. Similarly, hypoxic cells showed a slight reduction in strand break rejoining capacity compared to aerated cells. Under nutrient deprivation, anoxic cells displayed no SLD repair or strand break repair, while aerated cells exhibited the same level of SLD and strand break repair as for well-fed cells. In addition, nutrient deprived cells at low O 2 levels displayed normal SLD and strand break repair capability. These results indicate that both nutrient and O 2 deprivation are necessary for complete inhibition of cellular and molecular repair, and low levels of O 2 can effectively reverse this inhibition

  2. Interpretation of proton relative biological effectiveness using lesion induction, lesion repair, and cellular dose distribution

    International Nuclear Information System (INIS)

    Paganetti, H.

    2005-01-01

    Phenomenological biophysical models have been successfully used to estimate the relative biological effectiveness (RBE) of ions. The predictive power of these models is limited because they require measured dose-response data that are not necessarily available for all clinically relevant end points. Furthermore, input parameters often lack mechanistic interpretation. In order to link RBE to more fundamental biological parameters we combine the concepts of two well-established biophysical models, i.e., the phenomenological 'track structure' model and the more mechanistic 'lethal lesion/potentially lethal lesion' (LPL) model. We parametrize a relation between RBE, dose homogeneity in the cell nucleus and induction rates for different lesion types. The macroscopic dose-response relationship is described in the LPL model and the microscopic, subcellular, relationship is determined by the local dose deposition pattern. The formalism provides a framework for a mechanistic interpretation of RBE values

  3. Investigations of DNA damage induction and repair resulting from cellular exposure to high dose-rate pulsed proton beams

    International Nuclear Information System (INIS)

    Renis, M.; Malfa, G.; Tomasello, B.; Borghesi, M.; Schettino, G.; Favetta, M.; Romano, F.; Cirrone, G. A. P.; Manti, L.

    2013-01-01

    following irradiation in a dose-dependent manner. The analysis of repair capability showed that the cells irradiated with 1 and 2 Gy almost completely recovered from the damage, but not, however, 3 Gy treated cells in which DNA damage was not recovered. In addition, the results indicate the importance of the use of an appropriate control in radiobiological in vitro analysis

  4. Investigations of DNA damage induction and repair resulting from cellular exposure to high dose-rate pulsed proton beams

    Energy Technology Data Exchange (ETDEWEB)

    Renis, M.; Malfa, G.; Tomasello, B. [Drug Sciences Department, University of Catania, Catania (Italy); Borghesi, M.; Schettino, G. [Queen' s University Belfast, Northern Ireland (United Kingdom); Favetta, M.; Romano, F.; Cirrone, G. A. P. [National Institute for Nuclear Physics (INFN-LNS), Catania (Italy); Manti, L. [Physics Science Department, University of Naples Federico II, Naples, and National Institute for Nuclear Physics (INFN), Naples (Italy)

    2013-07-26

    following irradiation in a dose-dependent manner. The analysis of repair capability showed that the cells irradiated with 1 and 2 Gy almost completely recovered from the damage, but not, however, 3 Gy treated cells in which DNA damage was not recovered. In addition, the results indicate the importance of the use of an appropriate control in radiobiological in vitro analysis.

  5. Dose-response relationship of induction kinetics of In vivo DNA damage and repair in mouse leukocytes exposed to gamma radiation

    International Nuclear Information System (INIS)

    Mendiola C, M.T.; Morales, R.P.

    2000-01-01

    The Unicellular electrophoresis in gel technique is a useful tool in the determination of simple ruptures and labile sites to the alkali in DNA of eucariontes cells. The determination of the induction kinetics of damage and repair of DNA can give more information. The objective of this work was to determine whether the analysis of the area under the damage/repair induction kinetics curve in comets percent or the comets frequency in the two peaks of maximum induction is adequate for determining the dose-response relationship. The mice were exposed at the doses of 0.5, 1.0, 2.0 Gy. (Author)

  6. Late recovery of damage in rat spinal cord and bone marrow observed in split dose irradiation with long time intervals for 300 kV X-rays and 15 MeV neutrons

    International Nuclear Information System (INIS)

    Kogel, A.J. van der; Sissingh, H.A.

    The authors have performed an extended study on the capacity of the spinal cord for recovery of damage over long time intervals in split-dose experiments with 300 kV X-rays and 15 MeV neutrons, with time intervals of up to 30 weeks. The dose-response relationships for long term bone marrow depletion have been analysed and compared with those obtained for acute and late spinal cord damage. (Auth.)

  7. Recommendations to designers aimed at minimizing radiation dose incurred in operation, maintenance, inspection and repair of light-water reactors

    International Nuclear Information System (INIS)

    1978-01-01

    In the framework of the exchange of experience between nuclear power plant operators organized by the services of the Commission of the European Communities an ad-hoc working party elaborated recommendations particularly directed to those concerned with design of light water reactor plants. The necessary design measures which should be followed to minimize radiation dose incurred in operation, maintenance, inspection and repair of such reactors are listed. The recommendations are based on recent views expressed by operating utilities within the Community. It is intended to revise these recommendations at suitable intervals in order to make use of the most recent experience and to keep the report up to date with the actual state of art in nuclear technology

  8. Phase I trial of split-dose induction docetaxel, cisplatin, and 5-fluorouracil (TPF chemotherapy followed by curative surgery combined with postoperative radiotherapy in patients with locally advanced oral and oropharyngeal squamous cell cancer (TISOC-1

    Directory of Open Access Journals (Sweden)

    Oertel Katrin

    2012-10-01

    Full Text Available Abstract Background Induction chemotherapy (ICT with docetaxel, cisplatin and fluorouracil (TPF followed by radiotherapy is an effective treatment option for unresectable locally advanced head and neck cancer. This phase I study was designed to investigate the safety and tolerability of a split-dose TPF ICT regimen prior to surgery for locally advanced resectable oral and oropharyngeal cancer. Methods Patients received TPF split on two dosages on day 1 and 8 per cycle for one or three 3-week cycles prior to surgery and postoperative radiotherapy or radiochemotherapy. Docetaxel was escalated in two dose levels, 40 mg/m2 (DL 0 and 30 mg/m2 (DL −1, plus 40 mg/m2 cisplatin and 2000 mg/m2 fluorouracil per week using a 3 +3 dose escalation algorithm. Results Eighteen patients were enrolled and were eligible for toxicity and response. A maximum tolerated dose of 30 mg/m2 docetaxel per week was reached. The most common grade 3+ adverse event was neutropenia during ICT in 10 patients. Surgery reached R0 resection in all cases. Nine patients (50% showed complete pathologic regression. Conclusions A split-dose regime of TPF prior to surgery is feasible, tolerated and merits additional investigation in a phase II study with a dose of 30 mg/m docetaxel per week. Trial registration number NCT01108042 (ClinicalTrials.gov Identifier

  9. High-dose mode of mortality in Tribolium: A model system for study of radiation injury and repair in non-proliferative tissues

    International Nuclear Information System (INIS)

    Cheng, Chihing Christina.

    1989-01-01

    With appropriate doses of ionizing radiation, both the acute, or lethal-midlethal, dose-independent pattern of mortality, and the hyperacute, dose-dependent pattern, were demonstrated within a single insect genus (Tribolium). This demonstration provides resolution of apparently contradictory reports of insect radiation responses in terms of doses required to cause lethality and those based on survival time as a function of dose. A dose-dependent mortality pattern was elicited in adult Tribolium receiving high doses, viz., 300 Gy or greater; its time course was complete in 10 days, before the dose-independent pattern of mortality began. Visual observations of heavily-irradiated Tribolium suggested neural and/or neuromuscular damage, as had been previously proposed by others for lethally-irradiated wasps, flies, and mosquitoes. Results of experiments using fractionated high doses supported the suggestion that the hyperacute or high-dose mode of death is the result of damage to nonproliferative tissues. Relative resistance of a strain to the hyperacute or high-dose mode of death was not correlated with resistance to the midlethal mode, which is believed to be the result of damage to the proliferative cells of the midgut. Using the high-dose mode of death as a model of radiation damage to nonproliferative tissues, the effects of age, and of a moderate priming dose were assessed. Beetles showed age-related increase in sensitivity to the high-dose mode of death, suggesting a decline in capacity to repair radiation damage to postmitotic tissue. This correlated with a decrease (50%) in the amount of repair reflected in the sparing effect of dose-fractionation (SDF) between the age of 1 to 3 months. The age related increase in radiosensitivity was reduced by a moderate priming dose (40 or 65 Gy) given at a young age

  10. Effects of marrow grafting on preleukemia cells and thymic nurse cells in C57BL/Ka mice after a leukemogenic split-dose irradiation

    International Nuclear Information System (INIS)

    Defresne, M.P.; Greimers, R.; Lenaerts, P.; Boniver, J.

    1986-01-01

    A split-dose regimen of whole-body irradiation (4 X 175 rad at weekly intervals) induced thymic lymphomas in C57BL/Ka mice after a latent period of 3-9 months. Meanwhile, preleukemia cells arose in the thymus and bone marrow and persisted until the onset of lymphomas. Simultaneously, thymic lymphopoiesis was impaired; thymocyte numbers were subnormal and thymic nurse cells disappeared in a progressive but irreversible fashion. The depletion of these lymphoepithelial complexes, which are normally involved in the early steps of thymic lymphopoiesis, was related to altered prothymocyte activity in bone marrow and to damaged thymic microenvironment, perhaps as a consequence of the presence of preleukemia cells. The grafting of normal bone marrow cells after irradiation prevented the development of lymphomas. However, marrow reconstitution did not inhibit the induction of preleukemia cells. They disappeared from the thymus during the second part of the latent period. At the same time, thymic lymphopoiesis was restored; thymocytes and nurse cell numbers returned to normal as a consequence of the proliferation of grafted marrow-derived cells within the thymus. The results thus demonstrated an intimate relationship between preleukemia cells and an alteration of thymic lymphopoiesis, which particularly involved the nurse cell microenvironment. Some preleukemia cells in marrow-reconstituted, irradiated mice derived from the unirradiated marrow inoculate. Thus these cells acquired neoplastic potential through a factor present in the irradiated tissues. The nature of this indirect mechanism was briefly discussed

  11. The role of the DNA repair system in increasing the viability of E.coli cells under the action of small UV doses

    International Nuclear Information System (INIS)

    Kuzin, A.M.; Vilenchik, M.M.; Isakov, B.K.; AN Kazakhskoj SSR, Alma-Ata. Inst. Botaniki)

    1976-01-01

    The authors studied the action of the ultraviolet light (UV) on the colony-forming ability of E.coli K12-HCR + cultured in a meat infusion broth in the presence of glucose. An unusual shape of the curve indicates that the number of viable cells increases under the action of low UV doses. The experiment was repeated seven times, and each time the phenomenon was fully asserted (p 0.01). So it was suggested that low UV doses (about 140 erg/mm 2 ) activate the system of dark DNA repair (induction of the synthesis of repair enzymes) which repairs 'spontaneous' DNA defects and increases the number of colony-forming cells. (orig.) [de

  12. Role of the DNA repair system in increasing the viability of E. coli cells under the action of small UV doses

    Energy Technology Data Exchange (ETDEWEB)

    Kuzin, A M; Vilenchik, M M; Isakov, B K [AN SSSR, Pushchino-na-Oke. Inst. Biologicheskoj Fiziki; AN Kazakhskoj SSR, Alma-Ata. Inst. Botaniki)

    1976-12-01

    The authors studied the action of the ultraviolet light (UV) on the colony-forming ability of E.coli K12-HCR/sup +/ cultured in a meat infusion broth in the presence of glucose. An unusual shape of the curve indicates that the number of viable cells increases under the action of low UV doses. The experiment was repeated seven times, and each time the phenomenon was fully asserted (p 0.01). So it was suggested that low UV doses (about 140 erg/mm/sup 2/) activate the system of dark DNA repair (induction of the synthesis of repair enzymes) which repairs 'spontaneous' DNA defects and increases the number of colony-forming cells.

  13. Induction of mutations in blue-green alga Anacystis nidulans by consolidated and split UV irradiation

    International Nuclear Information System (INIS)

    Amla, D.V.

    1979-01-01

    Ultraviolet mutability of consolidated and split dose treatment in A. nidulans was investigated with reference to induction of phage- and streptomycin-resistant markers. The consolidated UV treatment induced both the markers about 100-150-fold, whereas under photoreactivating conditions the survival of alga was enhanced and mutation frequency was decreased. The split UV treatment with 6 hr dark incubation between two UV exposures enhanced the survival and mutation frequencies to 500-700 fold above the back-ground level. The data give indirect evidence for the presence of error-prone dark repair system in this organism. (auth.)

  14. Increasing the Dose of Autologous Chondrocytes Improves Articular Cartilage Repair: Histological and Molecular Study in the Sheep Animal Model.

    Science.gov (United States)

    Guillén-García, Pedro; Rodríguez-Iñigo, Elena; Guillén-Vicente, Isabel; Caballero-Santos, Rosa; Guillén-Vicente, Marta; Abelow, Stephen; Giménez-Gallego, Guillermo; López-Alcorocho, Juan Manuel

    2014-04-01

    We hypothesized that implanting cells in a chondral defect at a density more similar to that of the intact cartilage could induce them to synthesize matrix with the features more similar to that of the uninjured one. We compared the implantation of different doses of chondrocytes: 1 million (n = 5), 5 million (n = 5), or 5 million mesenchymal cells (n = 5) in the femoral condyle of 15 sheep. Tissue generated by microfracture at the trochlea, and normal cartilage from a nearby region, processed as the tissues resulting from the implantation, were used as references. Histological and molecular (expression of type I and II collagens and aggrecan) studies were performed. The features of the cartilage generated by implantation of mesenchymal cells and elicited by microfractures were similar and typical of a poor repair of the articular cartilage (presence of fibrocartilage, high expression of type I collagen and a low mRNA levels of type II collagen and aggrecan). Nevertheless, in the samples obtained from tissues generated by implantation of chondrocytes, hyaline-like cartilage, cell organization, low expression rates of type I collagen and high levels of mRNA corresponding to type II collagen and aggrecan were observed. These histological features, show less variability and are more similar to those of the normal cartilage used as control in the case of 5 million cells implantation than when 1 million cells were used. The implantation of autologous chondrocytes in type I/III collagen membranes at high density could be a promising tool to repair articular cartilage.

  15. Effect of a high-dose target-controlled naloxone infusion on pain and hyperalgesia in patients following groin hernia repair: study protocol for a randomized controlled trial

    DEFF Research Database (Denmark)

    Pereira, Manuel Pedro; Utke Werner, Mads; Berg Dahl, Joergen

    2015-01-01

    no volunteer developed significant secondary hyperalgesia after the placebo infusion. In order to consistently demonstrate latent sensitization in humans, a pain model inducing deep tissue inflammation, as used in animal studies, might be necessary. The aim of the present study is to examine whether a high......-dose target-controlled naloxone infusion can reinstate pain and hyperalgesia following recovery from open groin hernia repair and thus consistently demonstrate opioid-mediated latent sensitization in humans. METHODS/DESIGN: Patients submitted to unilateral, primary, open groin hernia repair will be included...

  16. Splitting Descartes

    DEFF Research Database (Denmark)

    Schilhab, Theresa

    2007-01-01

    Kognition og Pædagogik vol. 48:10-18. 2003 Short description : The cognitivistic paradigm and Descartes' view of embodied knowledge. Abstract: That the philosopher Descartes separated the mind from the body is hardly news: He did it so effectively that his name is forever tied to that division....... But what exactly is Descartes' point? How does the Kartesian split hold up to recent biologically based learning theories?...

  17. Split-dose administration of a dual-action, low-volume bowel cleanser for colonoscopy: the SEE CLEAR I study.

    Science.gov (United States)

    Rex, Douglas K; Katz, Philip O; Bertiger, Gerald; Vanner, Stephen; Hookey, Lawrence C; Alderfer, Vivian; Joseph, Raymond E

    2013-07-01

    New bowel cleansers for colonoscopy that lead to improved efficacy, safety, and tolerability are needed. This study evaluated a nonphosphate, dual-action, low-volume, orange-flavored preparation containing sodium picosulfate and magnesium citrate (P/MC). Multicenter, assessor-blinded, randomized, noninferiority study. University hospitals, academic medical centers, and private clinics across the United States. Adults preparing for colonoscopy. P/MC versus 2 L of polyethylene glycol solution (2L PEG-3350) and two 5-mg bisacodyl tablets. This phase 3 study investigated the efficacy, safety, and tolerability of split-dose administration of P/MC versus day-before dosing of 2L PEG-3350 and two 5-mg bisacodyl tablets (SEE CLEAR I study). Efficacy was evaluated by using the Aronchick and Ottawa scales; noninferiority and superiority analyses were performed. Safety was assessed by monitoring adverse events (AEs). Tolerability was measured via a patient questionnaire. The intent-to-treat population consisted of 601 patients who self-administered P/MC (n = 304) or 2L PEG-3350 and bisacodyl tablets (n = 297). P/MC was superior to 2L PEG-3350 and bisacodyl tablets in overall colon cleansing (84.2% vs 74.4%; 1-sided 97.5% confidence interval [CI], 3.4) (Aronchick scores of excellent or good) and in cleansing of the ascending (89.5% vs 78.8%; 1-sided 97.5% CI, 4.9), mid (transverse and descending) (92.4% vs 85.9%; 1-sided 97.5% CI, 1.6), and rectosigmoid (92.4% vs 87.2%; 1-sided 97.5% CI, 0.4) segments of the colon (Ottawa scores of excellent, good, or fair). Commonly reported AEs related to the bowel preparations were nausea, vomiting, headache, and chills. Patient-reported tolerability, including ease of consumption and taste, was significantly higher for P/MC than 2L PEG-3350 and bisacodyl tablets (P PEG-3350 and bisacodyl tablets. Copyright © 2013 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.

  18. The effects of different doses of IGF-1 on cartilage and subchondral bone during the repair of full-thickness articular cartilage defects in rabbits.

    Science.gov (United States)

    Zhang, Z; Li, L; Yang, W; Cao, Y; Shi, Y; Li, X; Zhang, Q

    2017-02-01

    To investigate the effects of different doses of insulin-like growth factor 1 (IGF-1) on the cartilage layer and subchondral bone (SB) during repair of full-thickness articular cartilage (AC) defects. IGF-1-loaded collagen membrane was implanted into full-thickness AC defects in rabbits. The effects of two different doses of IGF-1 on cartilage layer and SB adjacent to the defect, the cartilage structure, formation and integration, and the new SB formation were evaluated at the 1st, 4th and 8th week postoperation. Meanwhile, after 1 week treatment, the relative mRNA expressions in tissues adjacent to the defect, including cartilage and SB were determined by quantitative real-time RT-PCR (qRT-PCR), respectively. Different doses of IGF-1 induced different gene expression profiles in tissues adjacent to the defect and resulted in different repair outcomes. Particularly, at high dose IGF-1 aided cell survival, regulated the gene expressions in cartilage layer adjacent defect and altered ECM composition more effectively, improved the formation and integrity of neo-cartilage. While, at low dose IGF-1 regulated the gene expressions in SB more efficaciously and subsequently promoted the SB remodeling and reconstruction. Different doses of IGF-1 induced different responses of cartilage or SB during the repair of full-thickness AC defects. Particularly, high dose of IGF-1 was more beneficial to the neo-cartilage formation and integration, while low dose of it was more effective for the SB formation. Copyright © 2016 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

  19. Biological effect of pulsed dose rate brachytherapy with stepping sources if short half-times of repair are present in tissues

    International Nuclear Information System (INIS)

    Fowler, Jack F.; Limbergen, Erik F.M. van

    1997-01-01

    Purpose: To explore the possible increase of radiation effect in tissues irradiated by pulsed brachytherapy (PDR) for local tissue dose rates between those 'averaged over the whole pulse' and the instantaneous high dose rates close to the dwell positions. Increased effect is more likely for tissues with short half-times of repair of the order of a few minutes, similar to pulse durations. Methods and Materials: Calculations were done assuming the linear quadratic formula for radiation damage, in which only the dose-squared term is subject to exponential repair. The situation with two components of T (1(2)) is addressed. A constant overall time of 140 h and a constant total dose of 70 Gy were assumed throughout, the continuous low dose rate of 0.5 Gy/h (CLDR) providing the unitary standard effects for each PDR condition. Effects of dose rates ranging from 4 Gy/h to 120 Gy/h (HDR at 2 Gy/min) were studied, covering the gap in an earlier publication. Four schedules were examined: doses per pulse of 0.5, 1, 1.5, and 2 Gy given at repetition frequencies of 1, 2, 3, and 4 h, respectively, each with a range of assumed half-times of repair of 4 min to 1.5 h. Results are presented for late-responding tissues, the differences from CLDR being two or three times greater than for early-responding tissues and most tumors. Results: Curves are presented relating the ratio of increased biological effect (proportional to log cell kill) calculated for PDR relative to CLDR. Ratios as high as 1.5 can be found for large doses per pulse (2 Gy) if the half-time of repair in tissues is as short as a few minutes. The major influences on effect are dose per pulse, half-time of repair in tissue, and--when T (1(2)) is short--the instantaneous dose rate. Maximum ratios of PDR/CLDR occur when the dose rate is such that pulse duration is approximately equal to T (1(2)) . As dose rate in the pulse is increased, a plateau of effect is reached, for most T (1(2)) s, above 10 to 20 Gy/h, which is

  20. Modification of radiation dose-rate sparing effects in a human carcinoma of the cervix cell line by inhibitors of DNA repair

    Energy Technology Data Exchange (ETDEWEB)

    Kelland, L.R.; Steel, G.G.

    1988-08-01

    The in vitro cell survival of a human cervix carcinoma cell line (HX156c) was assessed using /sup 60/Co ..gamma..-rays administered at 150 cGy/min or 3.2 cGy/min dose rate. Recovery during low dose-rate irradiation was observed; dose reduction factor at 10/sup -2/ cell kill for 150 versus 3.2 cGy/min was around 1.3. Possible underlying mechanisms of this recovery process have been investigated by addition of non-toxic concentrations of various agents thought to inhibit eukaryotic DNA repair. Differential effects among inhibitors were observed; aphidicolin had no effect on cell survival, novobiocin, hydroxyurea and 3-aminobenzamide reduced survival by a similar extent at both dose rates, ..beta..-ara A and caffeine reduced survival to a greater extent during low dose-rate irradiation. ..beta..-ara A and caffeine seemed to effect mainly by increasing the alpha component of the acute survival curve. Since survival curves obtained at dose rates of around 3 cGy/min help define a dominant component of the initial slope of the acute curve the authors claim to demonstrate that ..beta..-ara A and caffeine modify the initial slope, probably by inhibiting DNA repair processes involved in tumour cell sparing during protracted irradiation.

  1. Endoleak detection using single-acquisition split-bolus dual-energy computer tomography (DECT)

    Energy Technology Data Exchange (ETDEWEB)

    Javor, D.; Wressnegger, A.; Unterhumer, S.; Kollndorfer, K.; Nolz, R.; Beitzke, D.; Loewe, C. [Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Vienna (Austria)

    2017-04-15

    To assess a single-phase, dual-energy computed tomography (DECT) with a split-bolus technique and reconstruction of virtual non-enhanced images for the detection of endoleaks after endovascular aneurysm repair (EVAR). Fifty patients referred for routine follow-up post-EVAR CT and a history of at least one post-EVAR follow-up CT examination using our standard biphasic (arterial and venous phase) routine protocol (which was used as the reference standard) were included in this prospective trial. An in-patient comparison and an analysis of the split-bolus protocol and the previously used double-phase protocol were performed with regard to differences in diagnostic accuracy, radiation dose, and image quality. The analysis showed a significant reduction of radiation dose of up to 42 %, using the single-acquisition split-bolus protocol, while maintaining a comparable diagnostic accuracy (primary endoleak detection rate of 96 %). Image quality between the two protocols was comparable and only slightly inferior for the split-bolus scan (2.5 vs. 2.4). Using the single-acquisition, split-bolus approach allows for a significant dose reduction while maintaining high image quality, resulting in effective endoleak identification. (orig.)

  2. Reduction of spontaneous somatic mutation frequency by a low-dose X irradiation of Drosophila larvae and possible involvement of DNA single-strand damage repair.

    Science.gov (United States)

    Koana, Takao; Takahashi, Takashi; Tsujimura, Hidenobu

    2012-03-01

    The third instar larvae of Drosophila were irradiated with X rays, and the somatic mutation frequency in their wings was measured after their eclosion. In the flies with normal DNA repair and apoptosis functions, 0.2 Gy irradiation at 0.05 Gy/min reduced the frequency of the so-called small spot (mutant cell clone with reduced reproductive activity) compared with that in the sham-irradiated flies. When apoptosis was suppressed using the baculovirus p35 gene, the small spot frequency increased four times in the sham-irradiated control group, but the reduction by the 0.2-Gy irradiation was still evident. In a non-homologous end joining-deficient mutant, the small spot frequency was also reduced by 0.2 Gy radiation. In a mutant deficient in single-strand break repair, no reduction in the small spot frequency by 0.2 Gy radiation was observed, and the small spot frequency increased with the radiation dose. Large spot (mutant cell clone with normal reproductive activity) frequency was not affected by suppression of apoptosis and increased monotonically with radiation dose in wild-type larvae and in mutants for single- or double-strand break repair. It is hypothesized that some of the small spots resulted from single-strand damage and, in wild-type larvae, 0.2 Gy radiation activated the normal single-strand break repair gene, which reduced the background somatic mutation frequency.

  3. The repair of low dose UV light-induced damage to human skin DNA in condition of trace amount Mg 2+

    Science.gov (United States)

    Gao, Fang; Guo, Zhouyi; Zheng, Changchun; Wang, Rui; Liu, Zhiming; Meng, Pei; Zhai, Juan

    2008-12-01

    Ultraviolet light-induced damage to human skin DNA was widely investigated. The primary mechanism of this damage contributed to form cyclobutane pyrimidine dimmers (CPDs). Although the distribution of UV light-induced CPDs within a defined sequence is similar, the damage in cellular environment which shields the nuclear DNA was higher than that in organism in apparent dose. So we use low UVB light as main study agent. Low dose UV-irradiated HDF-a cells (Human Dermal Fibroblasts-adult cells) which is weaker than epidermic cells were cultured with DMEM at different trace amount of Mg2+ (0mmol/L , 0.1mmol/L , 0.2mmol/L, 0.4mmol/L, 0.8mmol/L, 1.2mmol/L) free-serum DMEM and the repair of DNA strands injured were observed. Treat these cells with DNA strand breaks detection, photoproducts detection and the repair of photoproducts detection. Then quantitate the role of trace amount Mg2+ in repair of UV light-induced damage to human skin. The experiment results indicated that epidermic cells have capability of resistance to UV-radiation at a certain extent. And Mg2+ can regulate the UV-induced damage repair and relative vitality. It can offer a rationale and experiment data to relieve UV light-induced skin disease.

  4. Effect of chronic low dose natural radiation in human peripheral blood mononuclear cells: Evaluation of DNA damage and repair using the alkaline comet assay

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, P.R. Vivek, E-mail: prvkumar06@gmail.com [Low Level Radiation Research Laboratory, Radiation Biology and Health Sciences Division, Bio-Science Group, Bhabha Atomic Research Centre, IRE Campus, Beach Road, Kollam 691 001, Kerala (India); Seshadri, M. [Low Level Radiation Research Section, Radiation Biology and Health Sciences Division, Bio-Science Group, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Jaikrishan, G. [Low Level Radiation Research Laboratory, Radiation Biology and Health Sciences Division, Bio-Science Group, Bhabha Atomic Research Centre, IRE Campus, Beach Road, Kollam 691 001, Kerala (India); Das, Birajalaxmi [Low Level Radiation Research Section, Radiation Biology and Health Sciences Division, Bio-Science Group, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

    2015-05-15

    Highlights: • Effect of chronic low dose natural radiation in radio adaptive response studied. • PBMCs of subjects from NLNRA and HLNRA were challenged with gamma radiation. • DNA damage and repair in PBMCs was compared using the alkaline comet assay. • Significant reduction in DNA damage in subjects of high dose group from HLNRA noted. • Probable induction of an in vivo radio adaptive response in subjects from HLNRA. - Abstract: This study investigates whether peripheral blood mononuclear cells (PBMCs) from inhabitants of Kerala in southwest India, exposed to chronic low dose natural radiation in vivo (>1 mSv year{sup −1}), respond with a radioadaptive response to a challenging dose of gamma radiation. Toward this goal, PBMCs isolated from 77 subjects from high-level natural radiation areas (HLNRA) and 37 subjects from a nearby normal level natural radiation area (NLNRA) were challenged with 2 Gy and 4 Gy gamma radiation. Subjects from HLNRA were classified based on the mean annual effective dose received, into low dose group (LDG) and high dose group (HDG) with mean annual effective doses of 2.69 mSv (N = 43, range 1.07 mSv year{sup −1} to 5.55 mSv year{sup −1}) and 9.62 mSv (N = 34, range 6.07 mSv year{sup −1} to17.41 mSv year{sup −1}), respectively. DNA strand breaks and repair kinetics (at 7 min, 15 min and 30 min after 4 Gy) were evaluated using the alkaline single cell gel electrophoresis (comet) assay. Initial levels of DNA strand breaks observed after either a 2 Gy or a 4 Gy challenging dose were significantly lower in subjects of the HDG from HLNRA compared to subjects of NLNRA (2 Gy, P = 0.01; 4 Gy, P = 0.02) and LDG (2 Gy P = 0.01; 4 Gy, P = 0.05). Subjects of HDG from HLNRA showed enhanced rejoining of DNA strand breaks (HDG/NLNRA, P = 0.06) during the early stage of repair (within 7 min). However at later times a similar rate of rejoining of strand breaks was observed across the groups (HDG, LDG and NLNRA). Preliminary results from

  5. Repair of radiation damage caused by cyclotron-produced neutrons

    International Nuclear Information System (INIS)

    Martins, B.I.

    1979-01-01

    Hall et al. present experimental data on repair of sublethal damage in cultured mammalian cells exposed to 35 MeV neutrons and 60 Co γ rays. Hall and Kraljevic present experimental data on repair of potentially lethal damage in cultured mammalian cells exposed to 35 MeV neutrons and 210 kVp x rays. These results of Hall et al. are very difficult to explain from basic concepts in radiobiology. Contrary to Rossi, these data do not support his thesis that repair of radiation damage is dose-dependent and linear energy transfer independent. Nor do these results meet the expectations of multitarget-single hit theory which would require dose-independent repair equal to n. The observation of the same extrapolation number for neutrons and for x rays is also surprising. From the point of view of radiotherapy, the doses of interest are about 140 rad for neutrons and about 300 rad for x rays. There are no data for repair of potentially lethal damage below 800 rad for x rays and 400 rad for neutrons. The difference in survival between single and split dose is negligible up to a total of about 600 rad of x rays or of neutrons. These data of Hall et al. therefore have little significance to radiotherapists and are an enigma to radiobiologists

  6. Modification of damage following low doses

    International Nuclear Information System (INIS)

    Braby, L.A.; Nelson, J.M.; Metting, N.F.

    1988-01-01

    At very low doses the damage-interaction mechanism is responsible for very little lethal or potentially lethal damage, and repair of the latter should essentially disappear. An alternative model suggests that potentially lethal damage is either repaired with a constant half time or misrepaired at a rate which is proportional to the square of the damage concentration. In this case, as the dose decreases, the probability of misrepair decreases faster than the probability of repair, and repair becomes a more pronounced feature of the cell response. Since the consequence of unrepaired damage is an important question in determining the effects of low doses of radiation delivered at low dose rates, we have attempted to determine which of these two types of models is consistent with the response of plateau-phase CHO cells. In the earlier experiments, there was no indication of repair after a 50-rad exposure with a 24-hour split dose or plating delay; in fact, immediate plating resulted in survival slightly above control and delayed plating in survival slightly below the control value

  7. The experience from operation of electronic personal dosimetry system at Dukovany, Temelin and Mochovce NPPs after repair of Siemens dosemeters eliminating false doses

    International Nuclear Information System (INIS)

    Malysak, J.; Kocvara, S.; Jurochova, B.; Zelenka, Z.; Schacherl, M.; Zrubec, M.; Kaiser, H.

    2003-01-01

    This presentation summarizes the operational experience of the Electronic Personal Dosimetry Systems installed at Dukovany, Temelin and Mochovce NPPs. The system consists of three basic parts: Electronic personal dosemeters (EPD); Physical layer (HW); Logical layer (SW). Number of false doses before and after correction is presented. This presentation has demonstrated the possibilities of SEOD system and the possibility of easy dose comparison between the individual NPPs after introducing this electronic dosimetry system. Basically, the results of film and electronic dosimetry systems are according to our findings nearly identical. Electronic dosemeter sensitivity to interfering electromagnetic fields is a problem which is easily re-movable. In addition, if we know this problem, these false doses in the SEOD system can be easily revealed (e.g. by investigation of histograms) and repaired

  8. Low Dose Radiation-Induced Genome and Epigenome Instability Symposium and Epigenetic Mechanisms, DNA Repair, and Chromatin Symposium at the EMS 2008 Annual Meeting - October 2008

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, William F; Kovalchuk, Olga; Dolinoy, Dana C; Dubrova, Yuri E; Coleman, Matthew A; Schär, Primo; Pogribny, Igor; Hendzel, Michael

    2010-02-19

    The Low Dose Radiation Symposium thoughtfully addressed ionizing radiation non-mutational but transmissable alterations in surviving cells. Deregulation of epigenetic processes has been strongly implicated in carcinogenesis, and there is increasing realization that a significant fraction of non-targeted and adaptive mechanisms in response to ionizing radiation are likely to be epigenetic in nature. Much remains to be learned about how chromatin and epigenetic regulators affect responses to low doses of radiation, and how low dose radiation impacts other epigenetic processes. The Epigenetic Mechanisms Symposium focused on on epigenetic mechanisms and their interplay with DNA repair and chromatin changes. Addressing the fact that the most well understood mediators of epigenetic regulation are histone modifications and DNA methylation. Low levels of radiation can lead to changes in the methylation status of certain gene promoters and the expression of DNA methyltransferases, However, epigenetic regulation can also involve changes in higher order chromosome structure.

  9. Evaluation of genome damage and transcription profile of DNA damage/repair response genes in peripheral blood mononuclear cells exposed to low dose radiation

    International Nuclear Information System (INIS)

    Soren, D.C.; Saini, Divyalakshmi; Das, Birajalaxmi

    2016-01-01

    Humans are exposed to various physical and chemical mutagens in their life time. Physical mutagens, like ionizing radiation (IR), may induce adverse effect at high acute dose exposures in human cells. However, there are inconsistent results on the effect of low dose radiation exposure in human cells. There are a variety of DNA damage endpoints to evaluate the effect of low dose radiation in human cells. DNA damage response (DDR) may lead to changes in expression profile of many genes. In the present study, an attempt has been made to evaluate genome damage at low dose IR exposure in human blood lymphocytes. Cytochalasin blocked micronuclei (CBMN) assay has been used to determine the frequency of micronuclei in binucleated cells in PBMCs exposed to IR. Transcription profile of ATM, P53, GADD45A, CDKN1A, TRF1 and TRF2 genes was studied using real time quantitative PCR. Venous blood samples collected from 10 random healthy donors were irradiated with different doses of γ-radiation ( 137 Cs) along with sham irradiated control. Whole blood culture was set up using microculture technique. Blood samples were stimulated with phytohemagglutinin, and CBMN assay was performed. An average of 2,500 binucleated cells was scored for each dose point. For gene expression analysis, total RNA was isolated, cDNA was prepared, and gene expression analysis for ATM, P53, CDKN1A, GADD45A, TRF1 and TRF2 was done using real time PCR. Our results revealed no significant increase in the frequency of MN up to 100 mGy as compared to control. However, no significant alteration in gene expression profile was observed. In conclusion, no significant dose response was observed at the frequency of MN as well as the expression profile of DDR/repair genes, suggesting low dose radiation did not induce significant DNA damage at these acute dose exposures. (author)

  10. Radiation damage repair-preliminary studies

    International Nuclear Information System (INIS)

    Bird, R.P.

    1985-01-01

    An experiment was done with Cs-137 gamma rays to determine the effect of temperature on repair processes and cell-cycle progression. Chinese hamster V79 cells were synchronized with hydroxyurea to be at the G 1 /S transition at time T = O. Starting then at room temperature and either holding at room temperature of incubating at 37 0 C, the responses to a single dose at time T were compared, split doses separated by time T, were comparaed at different temperature, and delayed removal of hydroxyurea at the time T after a single dose at T = O was compared for the two temperatures. Reduced temperature was of minimal influence on the surviving fractions in all three cases. 9 refs., 1 fig

  11. Aspects of DNA repair and nucleotide pool imbalance

    Energy Technology Data Exchange (ETDEWEB)

    Holliday, R.

    1985-01-01

    Evidence that optimum repair depends on adequate pools of deoxynucleotide triphosphates (dNTPs) comes from the study of pyrimidine auxotrophs of Ustilago maydis. These strains are sensitive to UV light and X-rays, and for pyr1-1 it has been shown that the intracellular concentration of dTTP is reduced about 7-fold. The survival curve of pyr1-1 after UV-treatment, and split dose experiments with wild-type cells, provide evidence for an inducible repair mechanism, which probably depends on genetic recombination. Although inducible repair saves cellular resources, it has the disadvantage of becoming ineffective at doses which are high enough to inactivate the repressed structural gene(s) for repair enzymes. It is clear that a wide variety of repair mechanisms have evolved to remove lesions which arise either spontaneously or as a result of damage from external agents. Nevertheless, it would be incorrect to assume that all species require all possible pathways of repair. It is now well established that the accuracy of DNA and protein synthesis depends on proof-reading or editing mechanisms. Optimum accuracy levels will evolve from the balance between error avoidance in macromolecular synthesis and physiological efficiency in growth and propagation.

  12. Clamp wins pipe repair prize

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2001-04-01

    This paper describes the permanent pipeline repair system, developed by Tekmar, which is powered by seawater hydraulics and is easily installed and tested by any workclass remotely operated vehicle (rov). Details are given of the two main components of the system, namely, the diverless high pressure split repair clamp and the rov-operated tool to install it.

  13. Repair kinetics in tissues

    International Nuclear Information System (INIS)

    Thames, H.D.

    1989-01-01

    Monoexponential repair kinetics is based on the assumption of a single, dose-independent rate of repair of sublethal injury in the target cells for tissue injury after exposure to ionizing radiation. Descriptions of the available data based on this assumption have proved fairly successful for both acutely responding (skin, lip mucosa, gut) and late-responding (lung, spinal cord) normal tissues. There are indications of biphasic exponential repair in both categories, however. Unfortunately, the data usually lack sufficient resolution to permit unambiguous determination of the repair rates. There are also indications that repair kinetics may depend on the size of the dose. The data are conflicting on this account, however, with suggestions of both faster and slower repair after larger doses. Indeed, experiments that have been explicitly designed to test this hypothesis show either no effect (gut, spinal cord), faster repair after higher doses (lung, kidney), or slower repair after higher doses (skin). Monoexponential repair appears to be a fairly accurate description that provides an approximation to a more complicated picture, the elucidation of whose details will, however, require very careful and extensive experimental study. (author). 30 refs.; 1 fig

  14. Yield of radiation-induced DNA single-strand breaks in Escherichia coli and superinfecting phage lambda at different dose rates. Repair of strand breaks in different buffers

    International Nuclear Information System (INIS)

    Boye, E.; Johansen, I.; Brustad, T.

    1976-01-01

    Cells of E. coli K-12 strain AB 1886 were irradiated in oxygenated phosphate buffered saline at 2 0 C with electrons from a 4-MeV linear accelerator. The yield of DNA single-strand breaks was determined as a function of the dose rate between 2.5 and 21,000 krad/min. For dose rates over 100 krad/min the yield was found to be constant. Below 10 krad/min the yield of breaks decreases drastically. This is explained by rejoining of breaks during irradiation. Twenty percent of the breaks induced by acute exposure are repaired within 3 min at 2 0 C. Superinfecting phage lambda DNA is repaired at the same rate as chromosomal DNA. In contrast to the results obtained with phosphate-buffered saline, an increase in the number of breaks after irradiation is observed when the bacteria are suspended in tris buffer. It is suggested that buffers of low ionic strength facilitate the leakage through the membrane of a small-molecular-weight component(s) necessary for DNA strand rejoining

  15. Produtividade e qualidade de abacaxizeiro cv. Smooth Cayenne, cultivado comaplicação de doses e parcelamentos do nitrogênio, em Guaraçaí-SP Productivity and quality of pineapple cv. Smooth Cayenne, cultivated with nitrogen doses and splitting application in Guaraçaí-SP

    Directory of Open Access Journals (Sweden)

    Leandro Spegiorin Marques

    2011-09-01

    'Smooth Cayenne' subjected to nitrogen doses and splitting, grown in Guaraçai-SP. A randomized completely blocks design was carried out with four replications and sixteen treatments in a factorial scheme 4x4, with four doses of N: 7.5, 15, 22.5 and 30 g of N per plant, and four split doses: all the dose applied before floral induction, half the dose before floral induction and the other half after induction, 2 / 3 of the dose before induction and 1 / 3 of the dose after induction and the entire dose after floral induction. The total application of N after floral induction, regardless of the dose resulted in lower leaf N contents and leaf dimensions "D", featuring small fruit at the harvest, with lower maturation rates and higher acidity. To obtain pineapple fruits 'Smooth Cayenne', of bigger size and mass; higher TSS and lower acidity, the nitrogen fertilization can be applied in full dose before floral induction or split 2 / 3 before and 1 / 3 after this induction. Nitrogen fertilization has increased foliar concentrations of N, but had no effect on size, yield and fruit quality of pineapple cv. 'Smooth Cayenne'.

  16. Enhancement of postreplication repair in ultraviolet-light-irradiated Chinese hamster cells by irradiation in G2 or s-phase

    International Nuclear Information System (INIS)

    D'Ambrosio, S.M.; Aebersold, P.M.; Setlow, R.B.

    1978-01-01

    Postreplication repair in synchronous Chinese hamster cells was determined after split doses of ultraviolet (uv) radiation. Repair was enhanced by irradiation of cells in G 2 or S-phase with a small dose of uv radiation at least 1.5 h before a three-fold larger dose of uv. There was significantly greater enhancement when the first dose was given in G 2 than when it was given in the S-phase 0.5 to 1.5 h before the test dose. These data indicate that enhancement of postreplication repair does not require active DNA replication and qualitatively is independent of when in the cell cycle the cells are irradiated

  17. Action of 50 R X-ray doses on the breeding function of C3H strain mice - effect of splitting the dose, action of repeated irradiations on successive generations

    International Nuclear Information System (INIS)

    Alix, D.

    1965-01-01

    X-rays exposure effect was studied on C3H strain mice, at the standpoint of the effects produced on breeding function. The method used with this purpose was the following: single doses 20 - 30 - 40 and 50 R/dose, fractional doses: 50 R/total dose, divided in 2 - 5 - 10 or 25 irradiations distributed in one month duration. The offsprings were irradiated at the same doses than the parents, consanguinity being maintained. Statistical treatment of results was carried out, that led at the following conclusions: 1) Couples receiving single exposure of 50 R or two exposures of 25 R at one month interval give comparable results. Fractional doses do not involve the slightest diminution of X-rays effect. 2) 30 R exposure brings about a decrease in fertility, with an increase in abortions. Fertility of 20 R irradiated couples remains below controls. 3) After ten times 5 R and twenty-five 2 R, the number of abortions is the largest. Ovarian function is particularly sensitive to X-rays; one may think that twenty-five 2 R give injuries conditioning non-viability of conception products, smaller doses should produce mutations and yield births of altered genotype individuals. (author) [fr

  18. Functional genomics indicates yeast requires Golgi/ER transport, chromatin remodeling, and DNA repair for low dose DMSO tolerance

    Directory of Open Access Journals (Sweden)

    Brandon David Gaytán

    2013-08-01

    Full Text Available Dimethyl sulfoxide (DMSO is frequently utilized as a solvent in toxicological and pharmaceutical investigations. It is therefore important to establish the cellular and molecular targets of DMSO in order to differentiate its intrinsic effects from those elicited by a compound of interest. We performed a genome-wide functional screen in Saccharomyces cerevisiae to identify deletion mutants exhibiting sensitivity to 1% DMSO, a concentration standard to yeast chemical profiling studies. We report that mutants defective in Golgi/ER transport are sensitive to DMSO, including those lacking components of the conserved oligomeric Golgi (COG complex. Moreover, strains deleted for members of the SWR1 histone exchange complex are hypersensitive to DMSO, with additional chromatin remodeling mutants displaying a range of growth defects. We also identify DNA repair genes important for DMSO tolerance. Finally, we demonstrate that overexpression of histone H2A.Z, which replaces chromatin-associated histone H2A in a SWR1-catalyzed reaction, confers resistance to DMSO. Many yeast genes described in this study have homologs in more complex organisms, and the data provided is applicable to future investigations into the cellular and molecular mechanisms of DMSO toxicity.

  19. DIMETHYLARSINIC ACID ALTERS EXPRESSION OF OXIDATIVE STRESS AND DNA REPAIR GENES IN A DOSE DEPENDENT MANNER IN THE TRANSITIONAL EPITHELIUM OF THE URINARY BLADDER FROM FEMALE F344 RATS.

    Science.gov (United States)

    Dose-dependent alteration of oxidative stress and DNA repair gene expression by Dimethylarsinic acid [DMA(V)] in transitional epithelium of urinary bladder from female F344 rats.Arsenic (As) is a major concern as millions of people are at risk from drinking arsenic contaminat...

  20. Investigation of reference levels and radiation dose associated with abdominal EVAR (endovascular aneurysm repair) procedures across several European Centres

    Energy Technology Data Exchange (ETDEWEB)

    Tuthill, E.; Rainford, L. [University College Dublin, Diagnostic Imaging, School of Medicine, Dublin (Ireland); O' Hora, L.; O' Donohoe, M. [Mater Misericordiae University Hospital, Dublin (Ireland); Panci, S. [San Giovanni di Dio Hospital, Florence (Italy); Gilligan, P.; Fox, E. [Mater Private Hospital, Dublin (Ireland); Campion, D. [Mauriziano-Umberto Hospital, Turin (Italy); Trenti, R. [Policlinico S. Orsola-Malpighi, Bologna (Italy); Catania, D. [AITRI, Association of Italian Interventional Radiographers, Milan (Italy)

    2017-11-15

    Endovascular aneurysm repair (EVAR) is considered the treatment of choice for abdominal aortic aneurysms with suitable anatomy. In order to improve radiation safety, European Directive (2013/59) requires member states to implement diagnostic reference levels (DRLs) in radio-diagnostic and interventional procedures. This study aimed to determine local DRLs for EVAR across five European centres and identify an interim European DRL, which currently remains unestablished. Retrospective data was collected for 180 standard EVARs performed between January 2014 and July 2015 from five specialist centres in Ireland (n=2) and Italy (n=3). Data capture included: air kerma-area product (P{sub KA}), total air kerma at the reference point (K{sub a,r}), fluoroscopic time (FT), number of acquisitions, frame rate of acquisition, type of acquisition, patient height, weight, and gender. The mean values for each site A, B, C, D, and E were: P{sub KA}s of 4343 ± 994 μGym{sup 2}, 18,200 ± 2141 μGym{sup 2}, 11,423 ± 1390 μGym{sup 2}, 7796 ± 704 μGym{sup 2}, 31,897 ± 5798 μGym{sup 2}; FTs of 816 ± 92 s, 950 ± 150 s, 708 ± 70 s, 972 ± 61 s, 827 ± 118 s; and number of acquisitions of 6.72 ± 0.56, 10.38 ± 1.54, 4.74 ± 0.19, 5.64 ± 0.36, 7.28 ± 0.65, respectively. The overall pooled 75th percentile P{sub KA} was 15,849 μGym{sup 2}. Local reference levels were identified. The pooled data has been used to establish an interim European DRL for EVAR procedures. (orig.)

  1. DNA Base Excision Repair (BER) and Cancer Gene Therapy: Use of the Human N-mythlpurien DNA Glycosylase (MPG) to Sensitize Breast Cancer Cells to Low Dose Chemotherapy

    National Research Council Canada - National Science Library

    Harvey, Tia

    2003-01-01

    The DNA Base Excision Repair (PER) pathway is responsible for the repair of alkylation and oxidative DNA damage resulting in protection against the deleterious effects of endogenous and exogenous agents encountered on a daily basis...

  2. Nitrogênio na adubação química do cafeeiro: doses e parcelamentos do nitrocálcio Nitrogen fertilizer for coffee: rates and splitted applications of lime ammonium nitrate

    Directory of Open Access Journals (Sweden)

    Genésio da Silva Cervellini

    1986-01-01

    Full Text Available Nitrocálcio nas quantidades de 60, 120, 180 e 240 gramas de N por cafeeiro e por ano foi aplicado em parcelamentos diferentes, de acordo com os tratamentos e em três locais com início em 1973/74: Centro Experimental de Campinas, Estação Experimental de Mococa e Estação Experimental de Ribeirão Preto. Foram estudados os efeitos das quantidades crescentes e avaliadas as conveniências do parcelamento das doses de N aplicadas. Os acréscimos de produção com a elevação dessas doses foram bastante grandes até 120g, passando, a partir dessa quantidade, a aumentos menores. Os efeitos residuais do sulfato de amônio, Nitrocálcio, uréia e salitre-do-chile aplicados quatro anos antes do início do experimento ainda afetaram as produções, passados dez anos das últimas aplicações, reduzindo-as mais para as correspondentes ao salitre-do-chile e uréia. Os parcelamentos utilizados não favoreceram dados consistentes para conclusões, devendo seu estudo ter continuidade em novas séries de ensaios.Three experiments were carried out beginning in 1973/74 in a Red Latosol transition to Clay Red Yellow Latosol at the Centro Experimental of Campinas, in a Red-Yellow Podzolic Soil at Estação Experimental of Mococa, and on a Ortho Red Latosol at Estação Experimental of Ribeirão Preto, State of São Paulo, Brazil, in order to study nitrogen application on the coffee tree. Lime ammonium nitrate was applied at rates of 60, 120, 180, and 240g of N per plant in splitted applications as follows: in just one time by October and by December; in two times, by January and February; and in four times by October, December, January, and February. High yield increases were obtained with N applications rates up to 120g of N per plant. With higher rates further yield increments were about 5 or 10%. The residual effects of ammonium sulfate, lime ammonium nitrate, Chilean nitrate and urea were still present ten years after the last application. The data on

  3. Acute Normal Tissue Reactions in Head-and-Neck Cancer Patients Treated With IMRT: Influence of Dose and Association With Genetic Polymorphisms in DNA DSB Repair Genes

    International Nuclear Information System (INIS)

    Werbrouck, Joke; Ruyck, Kim de; Duprez, Frederic; Veldeman, Liv; Claes, Kathleen; Eijkeren, Marc van; Boterberg, Tom; Willems, Petra; Vral, Anne; Neve, Wilfried de; Thierens, Hubert

    2009-01-01

    Purpose: To investigate the association between dose-related parameters and polymorphisms in DNA DSB repair genes XRCC3 (c.-1843A>G, c.562-14A>G, c.722C>T), Rad51 (c.-3429G>C, c.-3392G>T), Lig4 (c.26C>T, c.1704T>C), Ku70 (c.-1310C>G), and Ku80 (c.2110-2408G>A) and the occurrence of acute reactions after radiotherapy. Materials and Methods: The study population consisted of 88 intensity-modulated radiation therapy (IMRT)-treated head-and-neck cancer patients. Mucositis, dermatitis, and dysphagia were scored using the Common Terminology Criteria (CTC) for Adverse Events v.3.0 scale. The population was divided into a CTC0-2 and CTC3+ group for the analysis of each acute effect. The influence of the dose on critical structures was analyzed using dose-volume histograms. Genotypes were determined by polymerase chain reaction (PCR) combined with restriction fragment length polymorphism or PCR-single base extension assays. Results: The mean dose (D mean ) to the oral cavity and constrictor pharyngeus (PC) muscles was significantly associated with the development of mucositis and dysphagia, respectively. These parameters were considered confounding factors in the radiogenomics analyses. The XRCC3c.722CT/TT and Ku70c.-1310CG/GG genotypes were significantly associated with the development of severe dysphagia (CTC3+). No association was found between the investigated polymorphisms and the development of mucositis or dermatitis. A risk analysis model for severe dysphagia, which was developed based on the XRCC3c.722CT/TT and Ku70c.-1310CG/GG genotypes and the PC dose, showed a sensitivity of 78.6% and a specificity of 77.6%. Conclusions: The XRCC3c.722C>T and Ku70c.-1310C>G polymorphisms as well as the D mean to the PC muscles were highly associated with the development of severe dysphagia after IMRT. The prediction model developed using these parameters showed a high sensitivity and specificity

  4. Coded Splitting Tree Protocols

    DEFF Research Database (Denmark)

    Sørensen, Jesper Hemming; Stefanovic, Cedomir; Popovski, Petar

    2013-01-01

    This paper presents a novel approach to multiple access control called coded splitting tree protocol. The approach builds on the known tree splitting protocols, code structure and successive interference cancellation (SIC). Several instances of the tree splitting protocol are initiated, each...... instance is terminated prematurely and subsequently iterated. The combined set of leaves from all the tree instances can then be viewed as a graph code, which is decodable using belief propagation. The main design problem is determining the order of splitting, which enables successful decoding as early...

  5. Early death, late death and repair factor in three human tumour cell lines

    International Nuclear Information System (INIS)

    Courdi, A.; Gioanni, J.; Mari, D.; Chauvel, P.

    1997-01-01

    The in vivo colony method used to generate survival curves following exposure to ionizing irradiation allows to score large clones, representing surviving cells, and small colonies, representing late reproductive death. By subtraction, early-dying cells can be estimated. In the three human tumour cell lines examined, we have observed that early cell death is a major mode of action of irradiation. The contribution of early cell death to total mortality increases as the dose increases. Moreover, repair due to dose-splitting and delayed plating in densely-inhibited cells is not observed in early-dying cells. (authors)

  6. Repair mechanisms and exposure standards

    International Nuclear Information System (INIS)

    Mills, W.A.

    1978-01-01

    The following topics are discussed; public policy for setting radiation standards; use of linear, nonthreshold theory in setting radiation standards; dose-rate dependence; occupational exposure to radiation; radon inhalation from radium in the soil in the vicinity of the phosphate industry; relation of repair mechanisms for cell survival to cancer induction; application of information on genetic repair to humans and to cancer induction; importance of repair processes in radiation protection standards; corrective factors for repair processes; relation of repair processes to age, sex, and other factors; and population distribution in radiosensitivity

  7. DNA repair

    International Nuclear Information System (INIS)

    Setlow, R.

    1978-01-01

    Some topics discussed are as follows: difficulty in extrapolating data from E. coli to mammalian systems; mutations caused by UV-induced changes in DNA; mutants deficient in excision repair; other postreplication mechanisms; kinds of excision repair systems; detection of repair by biochemical or biophysical means; human mutants deficient in repair; mutagenic effects of UV on XP cells; and detection of UV-repair defects among XP individuals

  8. Market Structure and Stock Splits

    OpenAIRE

    David Michayluk; Paul Kofman

    2001-01-01

    Enhanced liquidity is one possible motivation for stock splits but empirical research frequently documents declines in liquidity following stock splits. Despite almost thirty years of inquiry, little is known about all the changes in a stock's trading activity following a stock split. We examine how liquidity measures change around more than 2,500 stock splits and find a pervasive decline in most measures. Large stock splits exhibit a more severe liquidity decline than small stock splits, esp...

  9. Concentric Split Flow Filter

    Science.gov (United States)

    Stapleton, Thomas J. (Inventor)

    2015-01-01

    A concentric split flow filter may be configured to remove odor and/or bacteria from pumped air used to collect urine and fecal waste products. For instance, filter may be designed to effectively fill the volume that was previously considered wasted surrounding the transport tube of a waste management system. The concentric split flow filter may be configured to split the air flow, with substantially half of the air flow to be treated traveling through a first bed of filter media and substantially the other half of the air flow to be treated traveling through the second bed of filter media. This split flow design reduces the air velocity by 50%. In this way, the pressure drop of filter may be reduced by as much as a factor of 4 as compare to the conventional design.

  10. Protein synthesis and sublethal damage repair in synchronized CHO cells

    International Nuclear Information System (INIS)

    Yezzi, M.J.; Tobias, C.A.; Blakely, E.A.

    1984-01-01

    The authors have previously reported that the split dose survival response to x-rays of asynchronous CHO-TSH1 cells is reduced if the cells are held at 40 0 C,a temperature that inhibits protein synthesis, for 2 hours before the first dose and during a 2-hour interval between doses. In conjunction with the survival experiments on asynchronous cells, the authors also examined the DNA rejoining ability in split dose studies with and without inhibition of protein synthesis. The results of these experiments suggest that inhibition of protein synthesis affects a pool of proteins that are necessary for the correct expression of the DNA, although they do not appear to be involved in rejoining DNA breaks. They have extended this work to the study of cells synchronized in G1 phase (2 hour post-mitosis) and S phase (10 hour post-mitosis). Autoradiographic analyses, using 3H-TdR pulse labeling, demonstrated that a delay in the progression of each synchronized cell population occurs after inhibition of protein synthesis. Data are reported on the effects of inhibition of protein synthesis on the ability of G1 and S phase cells to repair sublethal damage

  11. Split Malcev algebras

    Indian Academy of Sciences (India)

    project of the Spanish Ministerio de Educación y Ciencia MTM2007-60333. References. [1] Calderón A J, On split Lie algebras with symmetric root systems, Proc. Indian. Acad. Sci (Math. Sci.) 118(2008) 351–356. [2] Calderón A J, On split Lie triple systems, Proc. Indian. Acad. Sci (Math. Sci.) 119(2009). 165–177.

  12. Stochastic split determinant algorithms

    International Nuclear Information System (INIS)

    Horvatha, Ivan

    2000-01-01

    I propose a large class of stochastic Markov processes associated with probability distributions analogous to that of lattice gauge theory with dynamical fermions. The construction incorporates the idea of approximate spectral split of the determinant through local loop action, and the idea of treating the infrared part of the split through explicit diagonalizations. I suggest that exact algorithms of practical relevance might be based on Markov processes so constructed

  13. Effect of single-dose low-level helium-neon laser irradiation on orthodontic pain: a split-mouth single-blind placebo-controlled randomized clinical trial.

    Science.gov (United States)

    Sobouti, Farhad; Khatami, Maziar; Chiniforush, Nasim; Rakhshan, Vahid; Shariati, Mahsa

    2015-01-01

    Pain is the most common complication of orthodontic treatment. Low-level laser therapy (LLLT) has been suggested as a new analgesic treatment free of the adverse effects of analgesic medications. However, it is not studied thoroughly, and the available studies are quite controversial. Moreover, helium neon (He-Ne) laser has not been assessed before. This split-mouth placebo-controlled randomized clinical trial was performed on 16 male and 14 female orthodontic patients requiring bilateral upper canine retraction. The study was performed at a private clinic in Sari, Iran, in 2014. It was single blind: patients, orthodontist, and personnel were blinded of the allocations, but the laser operator (periodontist) was not blinded. Once canine retractor was activated, a randomly selected maxillary quarter received a single dose of He-Ne laser irradiation (632.8 nm, 10 mw, 6 j/cm(2) density). The other quarter served as the placebo side, treated by the same device but powered off. In the first, second, fourth, and seventh days, blinded patients rated their pain sensed on each side at home using visual analog scale (VAS) questionnaires. There was no harm identified during or after the study. Pain changes were analyzed using two- and one-way repeated-measures ANOVA, Bonferroni, and t-test (α = 0.01, β > 0.99). This trial was not registered. It was self-funded by the authors. Sixteen males and 11 females remained in the study (aged 12-21). Average pain scores sensed in all 4 intervals on control and laser sides were 4.06 ± 2.85 and 2.35 ± 1.77, respectively (t-test P < 0.0001). One-way ANOVA showed significant pain declines over time, in each group (P < 0.0001). Two-way ANOVA showed significant effects for LLLT (P < 0.0001) and time (P = <0.0001). Single-dose He-Ne laser therapy might reduce orthodontic pain caused by retracting maxillary canines.

  14. Generalized field-splitting algorithms for optimal IMRT delivery efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Kamath, Srijit [Department of Radiation Oncology, University of Florida, Gainesville, FL (United States); Sahni, Sartaj [Department of Computer and Information Science and Engineering, University of Florida, Gainesville, FL (United States); Li, Jonathan [Department of Radiation Oncology, University of Florida, Gainesville, FL (United States); Ranka, Sanjay [Department of Computer and Information Science and Engineering, University of Florida, Gainesville, FL (United States); Palta, Jatinder [Department of Radiation Oncology, University of Florida, Gainesville, FL (United States)

    2007-09-21

    Intensity-modulated radiation therapy (IMRT) uses radiation beams of varying intensities to deliver varying doses of radiation to different areas of the tissue. The use of IMRT has allowed the delivery of higher doses of radiation to the tumor and lower doses to the surrounding healthy tissue. It is not uncommon for head and neck tumors, for example, to have large treatment widths that are not deliverable using a single field. In such cases, the intensity matrix generated by the optimizer needs to be split into two or three matrices, each of which may be delivered using a single field. Existing field-splitting algorithms used the pre-specified arbitrary split line or region where the intensity matrix is split along a column, i.e., all rows of the matrix are split along the same column (with or without the overlapping of split fields, i.e., feathering). If three fields result, then the two splits are along the same two columns for all rows. In this paper we study the problem of splitting a large field into two or three subfields with the field width as the only constraint, allowing for an arbitrary overlap of the split fields, so that the total MU efficiency of delivering the split fields is maximized. Proof of optimality is provided for the proposed algorithm. An average decrease of 18.8% is found in the total MUs when compared to the split generated by a commercial treatment planning system and that of 10% is found in the total MUs when compared to the split generated by our previously published algorithm. For more information on this article, see medicalphysicsweb.org.

  15. Tissue repair capacity and repair kinetics deduced from multifractionated or continuous irradiation regimens with incomplete repair

    International Nuclear Information System (INIS)

    Thames, H.D. Jr.; Peters, L.J.

    1984-01-01

    A model is proposed for cell survival after multiple doses, when the interfraction interval is insufficient for complete Elkind repair. In the limit of ever-increasing number of ever-smaller fractional doses, the model transforms into the accumulation model of survival after continuous irradiation. When adapted to describe tissue responses to isoeffective multifractionated regimens, wherein repair is incomplete, a generalization of the usually linear plot of reciprocal total dose versus dose per fraction is obtained, in which downward curvature is evident. There is an advantage in studying tissue responses to multifractionated regimens with incomplete repair in the interfraction intervals, or continuous exposures at various dose rates since, in addition to determination of repair capacity, there is an estimate of repair kinetics. Results of analyses of previously published data are presented as illustration. Estimated from the response of three acutely responding normal tissues in the mouse (jejunum, colon and bone marrow), repair halftimes ranged from 0.3-0.9 h and values of β/delta were approximately 0.1 Gy -1 . From the response of mouse lung (LD50 for pneumonitis) to multifractionated regimens with incomplete repair, the repair halftime was estimated at 1.5 h and β/delta was 0.27 Gy -1 . In the rat spinal cord β/delta was 0.7 Gy -1 and Tsub(1/2) was 1.5 h. (U.K.)

  16. Protection and repair of post-thrombolytic brain tissue with high-dose human albumin and magnesium sulfate: an experimental study

    International Nuclear Information System (INIS)

    Li Yongdong; Zhao Jungong; Li Minghua; You Xiaofang; Chen Yingsheng

    2008-01-01

    , local exudation of fluorescent materials with a mild microvascular dilation in group C and D comparing with group B. GFAP in group C and D at 6 h after stroke increased. The electron microscopy showed mild swelling of mitochondrion, moderate vacuolation of end-foot process of astrocyte, and no compression of the lumen of vessels of the vascular in group C and group D. Conclusions: Thrombolysis with rt-PA combined with high-dose human albumin and magnesium sulfate can reduce total infarct volume, accelarete the rCBV, promote astrocyte repairment with no increase incidence of cerebral hemorrhage in rats within 6 h after the onset of MCAO. (authors)

  17. Evaluation of Certain Pharmaceutical Quality Attributes of Lisinopril Split Tablets

    Directory of Open Access Journals (Sweden)

    Khairi M. S. Fahelelbom

    2016-10-01

    Full Text Available Tablet splitting is an accepted practice for the administration of drugs for a variety of reasons, including dose adjustment, ease of swallowing and cost savings. The purpose of this study was to evaluate the physical properties of lisinopril tablets as a result of splitting the tablets either by hand or with a splitting device. The impact of the splitting technique of lisinopril (Zestril® tablets, 20 mg on certain physical parameters such as weight variation, friability, disintegration, dissolution and drug content were studied. Splitting the tablets either by hand or with a splitter resulted in a minute but statistically significant average weight loss of <0.25% of the tablet to the surrounding environment. The variability in the weight of the hand-split tablet halves was more pronounced (37 out of 40 tablet halves varied by more than 10% from the mean weight than when using the tablet splitter (3 out of 40 tablet halves. The dissolution and drug content of the hand-split tablets were therefore affected because of weight differences. However, the pharmacopoeia requirements for friability and disintegration time were met. Hand splitting of tablets can result in an inaccurate dose and may present clinical safety issues, especially for drugs with a narrow therapeutic window in which large fluctuations in drug concentrations are undesirable. It is recommended to use tablets with the exact desired dose, but if this is not an option, then a tablet splitter could be used.

  18. Splitting Ward identity

    Energy Technology Data Exchange (ETDEWEB)

    Safari, Mahmoud [Institute for Research in Fundamental Sciences (IPM), School of Particles and Accelerators, P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of)

    2016-04-15

    Within the background-field framework we present a path integral derivation of the splitting Ward identity for the one-particle irreducible effective action in the presence of an infrared regulator, and make connection with earlier works on the subject. The approach is general in the sense that it does not rely on how the splitting is performed. This identity is then used to address the problem of background dependence of the effective action at an arbitrary energy scale. We next introduce the modified master equation and emphasize its role in constraining the effective action. Finally, application to general gauge theories within the geometric approach is discussed. (orig.)

  19. Splitting Ward identity

    International Nuclear Information System (INIS)

    Safari, Mahmoud

    2016-01-01

    Within the background-field framework we present a path integral derivation of the splitting Ward identity for the one-particle irreducible effective action in the presence of an infrared regulator, and make connection with earlier works on the subject. The approach is general in the sense that it does not rely on how the splitting is performed. This identity is then used to address the problem of background dependence of the effective action at an arbitrary energy scale. We next introduce the modified master equation and emphasize its role in constraining the effective action. Finally, application to general gauge theories within the geometric approach is discussed. (orig.)

  20. Alteration of split renal function during Captopril treatment

    International Nuclear Information System (INIS)

    Aburano, Tamio; Takayama, Teruhiko; Nakajima, Kenichi; Tonami, Norihisa; Hisada, Kinichi; Yasuhara, Shuichirou; Miyamori, Isamu; Takeda, Ryoyu

    1987-01-01

    Two different methods to evaluate the alteration of split renal function following continued Captopril treatment were studied in a total of 21 patients with hypertension. Eight patients with renovascular hypertension (five with unilateral renal artery stenosis and three with bilateral renal artery stenoses), three patients with diabetic nephropathy, one patient with primary aldosteronism, and nine patients with essential hypertension were included. The studies were performed the day prior to receiving Captopril (baseline), and 6th or 7th day following continued Captopril treatment (37.5 mg or 75 mg/day). Split effective renal plasma flow (ERPF) and glomerular filtration rate (GFR) after injections of I-131 hippuran and Tc-99m DTPA were measured using kidney counting corrected for depth and dose, described by Schlegel and Gates. In the patients with renovascular hypertension, split GFR in the stenotic kidney was significantly decreased 6th or 7th day following continued Captopril treatment compared to a baseline value. And split ERPF in the stenotic kidney was slightly increased although significant increase of split ERPF was not shown. In the patients with diabetic nephropathy, primary aldosteronism or essential hypertension, on the other hand, split GFR was not changed and split ERPF was slightly increased. These findings suggest that the Captopril induced alterations of split renal function may be of importance for the diagnosis of renovascular hypertension. For this purpose, split GFR determination is more useful than split ERPF determination. (author)

  1. The Splitting Loope

    Science.gov (United States)

    Wilkins, Jesse L. M.; Norton, Anderson

    2011-01-01

    Teaching experiments have generated several hypotheses concerning the construction of fraction schemes and operations and relationships among them. In particular, researchers have hypothesized that children's construction of splitting operations is crucial to their construction of more advanced fractions concepts (Steffe, 2002). The authors…

  2. The Splitting Group

    Science.gov (United States)

    Norton, Anderson; Wilkins, Jesse L. M.

    2012-01-01

    Piagetian theory describes mathematical development as the construction and organization of mental operations within psychological structures. Research on student learning has identified the vital roles of two particular operations--splitting and units coordination--play in students' development of advanced fractions knowledge. Whereas Steffe and…

  3. Role of protein synthesis in the repair of sublethal x-ray damage in a mutant Chinese hamster ovary cell line

    International Nuclear Information System (INIS)

    Yezzi, M.J.

    1985-04-01

    A temperature-sensitive mutant for protein synthesis, CHO-TSH1, has been compared to the wild-type cell, CHO-sC1, in single- and split-radiation-dose schemes. When the exponentially growing TS mutant and the wild-type cells were treated at 40 0 C for up to 2 hrs prior to graded doses of x rays, the survival curves were identical and were the same as those obtained without heat treatment. If the cultures were incubated at 40 0 C for 2 hrs before a first dose and maintained at 40 0 C during a 2 hr dose fractionation interval, repair of radiation damage was reduced in the mutant compared to the wild type. These observations implied that a pool of proteins was involved in the repair of sublethal x-ray damage. However, if repair was measured by the alkaline-unwinding technique under the same time and temperature schemes, no difference in the kientics of DNA strand rejoining was observed. Misrepair processes may permit restoration of DNA strand integrity but not allow functional repair. The effect of diminished repair under conditions of inhibition of protein synthesis was found to be cell-cycle dependent in survival studies with synchronized mutant cell populations. Repair was found to be almost completely eliminated if the temperature sequence described above was applied in the middle of the DNA synthetic phase. Treatment of cell populations in the middle of G 1 -phase yielded repair inhibition comparable to that observed with the asynchronous cells. Splitdose experiments were done using pre-incubation with cycloheximide to chemically inhibit protein synthesis. WT cells and TS cells were treated with cycloheximide at 35 0 C for 2 hrs before a first dose and during a 2 hr dose fractionation interval. 23 figs., 7 tabs

  4. Role of protein synthesis in the repair of sublethal x-ray damage in a mutant Chinese hamster ovary cell line

    Energy Technology Data Exchange (ETDEWEB)

    Yezzi, M.J.

    1985-04-01

    A temperature-sensitive mutant for protein synthesis, CHO-TSH1, has been compared to the wild-type cell, CHO-sC1, in single- and split-radiation-dose schemes. When the exponentially growing TS mutant and the wild-type cells were treated at 40/sub 0/C for up to 2 hrs prior to graded doses of x rays, the survival curves were identical and were the same as those obtained without heat treatment. If the cultures were incubated at 40/sup 0/C for 2 hrs before a first dose and maintained at 40/sup 0/C during a 2 hr dose fractionation interval, repair of radiation damage was reduced in the mutant compared to the wild type. These observations implied that a pool of proteins was involved in the repair of sublethal x-ray damage. However, if repair was measured by the alkaline-unwinding technique under the same time and temperature schemes, no difference in the kientics of DNA strand rejoining was observed. Misrepair processes may permit restoration of DNA strand integrity but not allow functional repair. The effect of diminished repair under conditions of inhibition of protein synthesis was found to be cell-cycle dependent in survival studies with synchronized mutant cell populations. Repair was found to be almost completely eliminated if the temperature sequence described above was applied in the middle of the DNA synthetic phase. Treatment of cell populations in the middle of G/sub 1/-phase yielded repair inhibition comparable to that observed with the asynchronous cells. Splitdose experiments were done using pre-incubation with cycloheximide to chemically inhibit protein synthesis. WT cells and TS cells were treated with cycloheximide at 35/sup 0/C for 2 hrs before a first dose and during a 2 hr dose fractionation interval. 23 figs., 7 tabs.

  5. Radiopotentiation by the oral platinum agent, JM216: role of repair inhibition

    International Nuclear Information System (INIS)

    Amorino, George P.; Freeman, Michael L.; Carbone, David P.; Lebwohl, David E.; Choy, Hak

    1999-01-01

    Purpose: To test for in vitro radiopotentiation by the orally-administered platinum (IV) complex, JM216; to compare these results to cisplatin and carboplatin; and to investigate whether the mechanism of radiopotentiation involves repair inhibition of radiation-induced DNA damage. Methods and Materials: H460 human lung carcinoma cells were incubated with the drugs for 1 h at 37 deg. C, irradiated at room temperature, and returned to 37 deg. C for 20 min. Cells were then rinsed and colony forming ability was assessed. Wild-type V79 Chinese hamster cells and radiosensitive, DNA repair-deficient mutant cells (XR-V15B) were also studied along with H460 cells. Ku86 cDNA, which encodes part of a protein involved in DNA repair, was transfected into XR-V15B cells as previously described. The effect of JM216 on sublethal damage repair (SLDR) was also assessed using split-dose recovery. Results: Using equally cytotoxic doses of JM216, cisplatin, and carboplatin, the radiation dose enhancement ratios (DER) were 1.39, 1.31, and 1.20, respectively; the DER with 20 μM JM216 was 1.57. JM216 (20 μM) did not significantly change the final slope of radiation survival curves, but greatly reduced the survival curve shoulder. V79 cells also showed radioenhancement using 20 μM JM216, but no enhancement occurred using XR-V15B cells. Transfection of Ku86 cDNA into XR-V15B cells restored radiopotentiation by JM216 to wild-type V79 levels. In addition, 20 μM JM216 completely inhibited sublethal damage repair in H460 cells. Conclusion: Our results show that JM216 can potentiate the effects of radiation in human lung cancer cells, and that the mechanism of this effect is probably inhibition of DNA repair by JM216

  6. Split warhead simultaneous impact

    Directory of Open Access Journals (Sweden)

    Rahul Singh Dhari

    2017-12-01

    Full Text Available A projectile system is proposed to improve efficiency and effectiveness of damage done by anti-tank weapon system on its target by designing a ballistic projectile that can split into multiple warheads and engage a target at the same time. This idea has been developed in interest of saving time consumed from the process of reloading and additional number of rounds wasted on target during an attack. The proposed system is achieved in three steps: Firstly, a mathematical model is prepared using the basic equations of motion. Second, An Ejection Mechanism of proposed warhead is explained with the help of schematics. Third, a part of numerical simulation which is done using the MATLAB software. The final result shows various ranges and times when split can be effectively achieved. With the new system, impact points are increased and hence it has a better probability of hitting a target.

  7. Isospin splittings of baryons

    International Nuclear Information System (INIS)

    Varga, Kalman; Genovese, Marco; Richard, Jean-Marc; Silvestre-Brac, Bernard

    1998-01-01

    We discuss the isospin-breaking mass differences among baryons, with particular attention in the charm sector to the Σ c + -Σ c 0 , Σ c ++ -Σ c 0 , and Ξ c + -Ξ c 0 splittings. Simple potential models cannot accommodate the trend of the available data on charm baryons. More precise measurements would offer the possibility of testing how well potential models describe the non-perturbative limit of QCD

  8. (O)Mega split

    Energy Technology Data Exchange (ETDEWEB)

    Benakli, Karim; Darmé, Luc; Goodsell, Mark D. [Sorbonne Universités, UPMC Univ Paris 06, UMR 7589,LPTHE, F-75005, Paris (France); CNRS, UMR 7589,LPTHE, F-75005, Paris (France)

    2015-11-16

    We study two realisations of the Fake Split Supersymmetry Model (FSSM), the simplest model that can easily reproduce the experimental value of the Higgs mass for an arbitrarily high supersymmetry scale M{sub S}, as a consequence of swapping higgsinos for equivalent states, fake higgsinos, with suppressed Yukawa couplings. If the LSP is identified as the main Dark matter component, then a standard thermal history of the Universe implies upper bounds on M{sub S}, which we derive. On the other hand, we show that renormalisation group running of soft masses aboveM{sub S} barely constrains the model — in stark contrast to Split Supersymmetry — and hence we can have a “Mega Split” spectrum even with all of these assumptions and constraints, which include the requirements of a correct relic abundance, a gluino life-time compatible with Big Bang Nucleosynthesis and absence of signals in present direct detection experiments of inelastic dark matter. In an appendix we describe a related scenario, Fake Split Extended Supersymmetry, which enjoys similar properties.

  9. Exciting News From Va. Tech - Repaired Pallets May Be Stronger Than the Original

    Science.gov (United States)

    John W. Clarke; Marshall S. White; T.E. McLain; Philip A. Araman

    1995-01-01

    Virginia Tech, in cooperation with the NWPCA and the Southern Research Station of the USDA Forest Service, conducted a research program on the use of metal plates for repair of stringer pallets. This study looked at common stringer failure locations: splits between the notches, splits above the notches, and splits in the end feet. One of the research objectives was to...

  10. Saturation of DNA repair in mammalian cells

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, F E; Setlow, R B

    1979-01-01

    Excision repair seems to reach a plateau in normal human cells at a 254 nm dose near 20 J/m/sup 2/. We measured excision repair in normal human fibroblasts up to 80 J/m/sup 2/. The four techniques used (unscheduled DNA synthesis, photolysis of BrdUrd incorporated during repair, loss of sites sensitive to a UV endonuclease from Micrococcus luteus, and loss of pyrimidine dimers from DNA) showed little difference between the two doses. Moreover, the loss of endonuclease sites in 24h following two 20 J/m/sup 2/ doses separated by 24h was similar to the loss observed following one dose. Hence, we concluded that the observed plateau in excision repair is real and does not represent some inhibitory process at high doses but a true saturation of one of the rate limiting steps in repair.

  11. Mountain Plains Learning Experience Guide: Electric Motor Repair.

    Science.gov (United States)

    Ziller, T.

    This Electric Motor Repair Course is designed to provide the student with practical information for winding, repairing, and troubleshooting alternating current and direct current motors, and controllers. The course is comprised of eight units: (1) Electric Motor Fundamentals, (2) Rewinding, (3) Split-phase Induction Motors, (4) Capacitor Motors,…

  12. Role of protein synthesis in the repair of sublethal x-ray damage in a mutant Chinese hamster ovary cell line

    International Nuclear Information System (INIS)

    Yezzi, M.J.

    1985-01-01

    A temperature-sensitive mutant for protein synthesis, CHO-TSH1, was compared to the wild-type cell, CHO-SC1, in single- and split-radiation-dose schemes. When the cultures were incubated at 40 0 C for 2 hrs before a first dose and maintained at 40 0 C during a 2 hr dose fractionation interval, repair of radiation damage was reduced in the mutant compared to the wild type. These observations implied that a pool of proteins was involved in the repair of sublethal X-ray damage. The effect of diminished repair under conditions of inhibition of protein synthesis was found to be cell-cycle dependent in survival studies with synchronized mutant cell populations. Repair was found to be almost completely eliminated if the temperature sequence described above was applied in the middle of the DNA synthetic phase. Distinct perturbations in the cell-cycle progression were noted following heat alone or heat with radiation. A delay in the progression of synchronized G 1 -phase and S-phase cells was demonstrated autoradiographically after inhibition of protein synthesis. In addition, treated S-phase cells showed a transient increase in the percent labelled cells after the cells were returned to their normal growth temperature of 35 0 C. This observation was suggestive of an unusual pattern of DNA synthesis during the recovery period. Split-dose experiments were done using incubation with cycloheximide to chemically inhibit protein synthesis. Both the chemical and thermal inhibition of protein synthesis substantiate its necessity for the repair of sublethal damage

  13. Biological repair with time-dependent irradiation

    International Nuclear Information System (INIS)

    Broyles, A.A.; Shapiro, C.S.

    1985-01-01

    Recent experiments have provided new data that explore the effectiveness of biological repair in assessing damage due to exposures from ionizing radiation. These data are mainly from experiments conducted at constant dose rates, to study the effectiveness per unit dose of different dose rates. Here, we develop new formulae to estimate the effectiveness of an arbitrary time-dependent dose rate exposure

  14. Meningocele repair

    Science.gov (United States)

    ... is surgery to repair birth defects of the spine and spinal membranes. Meningocele and myelomeningocele ... is covered by a sterile dressing. Your child may then be transferred to a neonatal intensive ...

  15. Geometrical splitting in Monte Carlo

    International Nuclear Information System (INIS)

    Dubi, A.; Elperin, T.; Dudziak, D.J.

    1982-01-01

    A statistical model is presented by which a direct statistical approach yielded an analytic expression for the second moment, the variance ratio, and the benefit function in a model of an n surface-splitting Monte Carlo game. In addition to the insight into the dependence of the second moment on the splitting parameters the main importance of the expressions developed lies in their potential to become a basis for in-code optimization of splitting through a general algorithm. Refs

  16. Radiobiological responses for two cell lines following continuous low dose-rate (CLDR) and pulsed dose rate (PDR) brachytherapy

    International Nuclear Information System (INIS)

    Hanisch, Per Henrik; Furre, Torbjoern; Olsen, Dag Rune; Pettersen, Erik O.

    2007-01-01

    The iso-effective irradiation of continuous low-dose-rate (CLDR) irradiation was compared with that of various schedules of pulsed dose rate (PDR) irradiation for cells of two established human lines, T-47D and NHIK 3025. Complete single-dose response curves were obtained for determination of parameters α and β by fitting of the linear quadratic formula. Sublethal damage repair constants μ and T 1/2 were determined by split-dose recovery experiments. On basis of the acquired parameters of each cell type the relative effectiveness of the two regimens of irradiation (CLDR and PDR) was calculated by use of Fowler's radiobiological model for iso-effect irradiation for repeated fractions of dose delivered at medium dose rates. For both cell types the predicted and observed relative effectiveness was compared at low and high iso-effect levels. The results indicate that the effect of PDR irradiation predicted by Fowler's model is equal to that of CLDR irradiation for both small and large doses with T-47D cells. With NHIK 3025 cells PDR irradiation induces a larger effect than predicted by the model for small doses, while it induces the predicted effect for high doses. The underlying cause of this difference is unclear, but cell-cycle parameters, like G2-accumulation is tested and found to be the same for the two cell lines

  17. Dose-response relationship of induction kinetics of In vivo DNA damage and repair in mouse leukocytes exposed to gamma radiation; Relacion dosis-respuesta de la cinetica de induccion de dano y reparacion del ADN In vivo en leucocitos de raton expuestos a radiacion gamma

    Energy Technology Data Exchange (ETDEWEB)

    Mendiola C, M.T.; Morales, R.P. [Instituto Nacional de Investigaciones Nucleares, Gerencia de Investigacion Basica, Departamento de Biologia, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    2000-07-01

    The Unicellular electrophoresis in gel technique is a useful tool in the determination of simple ruptures and labile sites to the alkali in DNA of eucariontes cells. The determination of the induction kinetics of damage and repair of DNA can give more information. The objective of this work was to determine whether the analysis of the area under the damage/repair induction kinetics curve in comets percent or the comets frequency in the two peaks of maximum induction is adequate for determining the dose-response relationship. The mice were exposed at the doses of 0.5, 1.0, 2.0 Gy. (Author)

  18. DNA repair

    International Nuclear Information System (INIS)

    Van Zeeland, A.A.

    1984-01-01

    In this chapter a series of DNA repair pathways are discussed which are available to the cell to cope with the problem of DNA damaged by chemical or physical agents. In the case of microorganisms our knowledge about the precise mechanism of each DNA repair pathway and the regulation of it has been improved considerably when mutants deficient in these repair mechanisms became available. In the case of mammalian cells in culture, until recently there were very little repair deficient mutants available, because in almost all mammalian cells in culture at least the diploid number of chromosomes is present. Therefore the frequency of repair deficient mutants in such populations is very low. Nevertheless because replica plating techniques are improving some mutants from Chinese hamsters ovary cells and L5178Y mouse lymphoma cells are now available. In the case of human cells, cultures obtained from patients with certain genetic diseases are available. A number of cells appear to be sensitive to some chemical or physical mutagens. These include cells from patients suffering from xeroderma pigmentosum, Ataxia telangiectasia, Fanconi's anemia, Cockayne's syndrome. However, only in the case of xeroderma pigmentosum cells, has the sensitivity to ultraviolet light been clearly correlated with a deficiency in excision repair of pyrimidine dimers. Furthermore the work with strains obtained from biopsies from man is difficult because these cells generally have low cloning efficiencies and also have a limited lifespan in vitro. It is therefore very important that more repair deficient mutants will become available from established cell lines from human or animal origin

  19. Molecular concepts of water splitting. Nature's approach

    International Nuclear Information System (INIS)

    Cox, Nicholas; Lubitz, Wolfgang

    2013-01-01

    Based on studies of natural systems, much has also been learned concerning the design principles required for biomimetic catalysis of water splitting and hydrogen evolution. In summary, these include use of abundant and inexpensive metals, the effective protection of the active sites in functional environments, repair/replacement of active components in case of damage, and the optimization of reaction rates. Biomimetic chemistry aims to mimic all these features; many labs are working toward this goal by developing new approaches in the design and synthesis of such systems, encompassing not only the catalytic center, but also smart matrices and assembly via self-organization. More stable catalysts that do not require self-repair may be obtained from fully artificial (inorganic) catalytic systems that are totally different from the biological ones and only apply some basic principles learned from nature. Metals other than Mn/Ca, Fe, and Ni could be used (e.g. Co) in new ligand spheres and other matrices. For light harvesting, charge separation/stabilization, and the effective coupling of the oxidizing/reducing equivalents to the redox catalysts, different methods have been proposed - for example, covalently linked molecular donor-acceptor systems, photo-voltaic devices, semiconductor-based systems, and photoactive metal complexes. The aim of all these approaches is to develop catalytic systems that split water with sunlight into hydrogen and oxygen while displaying high efficiency and long-term stability. Such a system - either biological, biomimetic, or bioinspired - has the potential to be used on a large scale to produce 'solar fuels' (e.g. hydrogen or secondary products thereof). (orig.)

  20. Human papillomavirus type 16 E7 oncoprotein causes a delay in repair of DNA damage

    International Nuclear Information System (INIS)

    Park, Jung Wook; Nickel, Kwangok P.; Torres, Alexandra D.; Lee, Denis; Lambert, Paul F.; Kimple, Randall J.

    2014-01-01

    Background and purpose: Patients with human papillomavirus related (HPV+) head and neck cancers (HNCs) demonstrate improved clinical outcomes compared to traditional HPV negative (HPV−) HNC patients. We have recently shown that HPV+ HNC cells are more sensitive to radiation than HPV− HNC cells. However, roles of HPV oncogenes in regulating the response of DNA damage repair remain unknown. Material and methods: Using immortalized normal oral epithelial cell lines, HPV+ HNC derived cell lines, and HPV16 E7-transgenic mice we assessed the repair of DNA damage using γ-H2AX foci, single and split dose clonogenic survival assays, and immunoblot. The ability of E7 to modulate expression of proteins associated with DNA repair pathways was assessed by immunoblot. Results: HPV16 E7 increased retention of γ-H2AX nuclear foci and significantly decreased sublethal DNA damage repair. While phospho-ATM, phospho-ATR, Ku70, and Ku80 expressions were not altered by E7, Rad51 was induced by E7. Correspondingly, HPV+ HNC cell lines showed retention of Rad51 after γ-radiation. Conclusions: Our findings provide further understanding as to how HPV16 E7 manipulates cellular DNA damage responses that may underlie its oncogenic potential and influence the altered sensitivity to radiation seen in HPV+ HNC as compared to HPV− HNC

  1. Maternal methadone dosing schedule and fetal neurobehavior

    Science.gov (United States)

    Jansson, Lauren M.; DiPietro, Janet A.; Velez, Martha; Elko, Andrea; Knauer, Heather; Kivlighan, Katie T.

    2008-01-01

    Objective Daily methadone maintenance is the standard of care for opiate dependency during pregnancy. Previous research has indicated that single-dose maternal methadone administration significantly suppresses fetal neurobehaviors. The purpose of this study was to determine if split-dosing would have less impact on fetal neurobehavior than single-dose administration. Methods Forty methadone-maintained women were evaluated at peak and trough maternal methadone levels on single- and split-dosing schedules. Monitoring sessions occurred at 36 and 37 weeks gestation in a counterbalanced study design. Fetal measures included heart rate, variability, accelerations, motor activity and fetal movement-heart rate coupling (FM-FHR). Maternal measures included heart period, variability, skin conductance, respiration and vagal tone. Repeated measure analysis of variance was used to evaluate within-subject changes between split- and single-dosing regimens. Results All fetal neurobehavioral parameters were suppressed by maternal methadone administration, regardless of dosing regimen. Fetal parameters at peak were significantly lower during single vs. split methadone administration. FM-FHR coupling was less suppressed from trough to peak during split-dosing vs. single-dosing. Maternal physiologic parameters were generally unaffected by dosing condition. Conclusion Split- dosed fetuses displayed less neurobehavioral suppression from trough to peak maternal methadone levels as compared to single-dosed fetuses. Split-dosing may be beneficial for methadone-maintained pregnant women. PMID:19085624

  2. Repair process and a repaired component

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, III, Herbert Chidsey; Simpson, Stanley F.

    2018-02-20

    Matrix composite component repair processes are disclosed. The matrix composite repair process includes applying a repair material to a matrix composite component, securing the repair material to the matrix composite component with an external securing mechanism and curing the repair material to bond the repair material to the matrix composite component during the securing by the external securing mechanism. The matrix composite component is selected from the group consisting of a ceramic matrix composite, a polymer matrix composite, and a metal matrix composite. In another embodiment, the repair process includes applying a partially-cured repair material to a matrix composite component, and curing the repair material to bond the repair material to the matrix composite component, an external securing mechanism securing the repair material throughout a curing period, In another embodiment, the external securing mechanism is consumed or decomposed during the repair process.

  3. Radiation-induced strand-breaks and DNA-protein crosslinks depend predominantly on the dose, oxygen concentration and repair time

    International Nuclear Information System (INIS)

    Wheeler, K.T.; Miyagi, Y.; Zhang, H.

    1995-01-01

    It has been known for many years that the DNA damage produced by ionizing radiation depends upon the oxygen concentration around the DNA. For example, the number of DNA strand-breaks (SBs) formed per unit dose decreases at low oxygen concentrations, and the number of DNA-protein crosslinks formed per unit dose increases at low oxygen concentrations. If radiation-induced SBs and DPCs are to be useful for detecting and/or quantifying hypoxic cells in solid tumors, the formation of these lesions must depend predominantly on the oxygen concentration around the DNA. All other physical, biological, and physiological factors must either be controllable or have little influence on the assay used to measure these lesions. This paper is a summary of the authors' recent experiments to determine if the radiation-induced SBs and DPCs measured by alkaline elution may be used to estimate the hypoxic fraction or fractional hypoxic volume of solid tumors

  4. Evidence for dark repair of far ultraviolet light damage in the blue-green alga, Gloeocapsa alpicola

    International Nuclear Information System (INIS)

    Williams, E.; Lambert, J.; O'Brien, P.; Houghton, J.A.

    1979-01-01

    The inactivating effect of far UV light on the unicellular blue-green alga Gloeocapsa alpicola could be totally reversed by exposure to blue light immediately after irradiation. However, if the irradiated cells were held in the dark before exposure to blue light, reversal became progressively less efficient, and almost disappeared after 60-80 h holding. Caffeine and acriflavine inhibited loss of photoreversibility, suggesting an involvement of excision functions. Chloramphenicol and rifampicin slightly increased the rate of loss of photoreversibility, indicating that inducible functions play only a minor role. Split UV dose experiments indicated that light-dependent repair remained operational during dark liquid holding. These results provide preliminary evidence for dark repair in G. alpicola. (author)

  5. Motorcycle Repair.

    Science.gov (United States)

    Hein, Jim; Bundy, Mike

    This motorcycle repair curriculum guide contains the following ten areas of study: brake systems, clutches, constant mesh transmissions, final drives, suspension, mechanical starting mechanisms, electrical systems, fuel systems, lubrication systems, and overhead camshafts. Each area consists of one or more units of instruction. Each instructional…

  6. DNA repair related to radiation therapy

    International Nuclear Information System (INIS)

    Klein, W.

    1979-01-01

    The DNA excision repair capacity of peripheral human lymphocytes after radiation therapy has been analyzed. Different forms of application of the radiation during the therapy have been taken into account. No inhibition of repair was found if cells were allowed a certain amount of accomodation to radiation, either by using lower doses or longer application times. (G.G.)

  7. Split-illumination electron holography

    Energy Technology Data Exchange (ETDEWEB)

    Tanigaki, Toshiaki; Aizawa, Shinji; Suzuki, Takahiro; Park, Hyun Soon [Advanced Science Institute, RIKEN, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan); Inada, Yoshikatsu [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Sendai 980-8577 (Japan); Matsuda, Tsuyoshi [Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012 (Japan); Taniyama, Akira [Corporate Research and Development Laboratories, Sumitomo Metal Industries, Ltd., Amagasaki, Hyogo 660-0891 (Japan); Shindo, Daisuke [Advanced Science Institute, RIKEN, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan); Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Sendai 980-8577 (Japan); Tonomura, Akira [Advanced Science Institute, RIKEN, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan); Okinawa Institute of Science and Technology, Graduate University, Onna-son, Okinawa 904-0495 (Japan); Central Research Laboratory, Hitachi, Ltd., Hatoyama, Saitama 350-0395 (Japan)

    2012-07-23

    We developed a split-illumination electron holography that uses an electron biprism in the illuminating system and two biprisms (applicable to one biprism) in the imaging system, enabling holographic interference micrographs of regions far from the sample edge to be obtained. Using a condenser biprism, we split an electron wave into two coherent electron waves: one wave is to illuminate an observation area far from the sample edge in the sample plane and the other wave to pass through a vacuum space outside the sample. The split-illumination holography has the potential to greatly expand the breadth of applications of electron holography.

  8. Split-illumination electron holography

    International Nuclear Information System (INIS)

    Tanigaki, Toshiaki; Aizawa, Shinji; Suzuki, Takahiro; Park, Hyun Soon; Inada, Yoshikatsu; Matsuda, Tsuyoshi; Taniyama, Akira; Shindo, Daisuke; Tonomura, Akira

    2012-01-01

    We developed a split-illumination electron holography that uses an electron biprism in the illuminating system and two biprisms (applicable to one biprism) in the imaging system, enabling holographic interference micrographs of regions far from the sample edge to be obtained. Using a condenser biprism, we split an electron wave into two coherent electron waves: one wave is to illuminate an observation area far from the sample edge in the sample plane and the other wave to pass through a vacuum space outside the sample. The split-illumination holography has the potential to greatly expand the breadth of applications of electron holography.

  9. Two-Loop Splitting Amplitudes

    International Nuclear Information System (INIS)

    Bern, Z.

    2004-01-01

    Splitting amplitudes govern the behavior of scattering amplitudes at the momenta of external legs become collinear. In this talk we outline the calculation of two-loop splitting amplitudes via the unitarity sewing method. This method retains the simple factorization properties of light-cone gauge, but avoids the need for prescriptions such as the principal value or Mandelstam-Leibbrandt ones. The encountered loop momentum integrals are then evaluated using integration-by-parts and Lorentz invariance identities. We outline a variety of applications for these splitting amplitudes

  10. Two-loop splitting amplitudes

    International Nuclear Information System (INIS)

    Bern, Z.; Dixon, L.J.; Kosower, D.A.

    2004-01-01

    Splitting amplitudes govern the behavior of scattering amplitudes at the momenta of external legs become collinear. In this talk we outline the calculation of two-loop splitting amplitudes via the unitarity sewing method. This method retains the simple factorization properties of light-cone gauge, but avoids the need for prescriptions such as the principal value or Mandelstam-Leibbrandt ones. The encountered loop momentum integrals are then evaluated using integration-by-parts and Lorentz invariance identities. We outline a variety of applications for these splitting amplitudes

  11. Turbine repair process, repaired coating, and repaired turbine component

    Science.gov (United States)

    Das, Rupak; Delvaux, John McConnell; Garcia-Crespo, Andres Jose

    2015-11-03

    A turbine repair process, a repaired coating, and a repaired turbine component are disclosed. The turbine repair process includes providing a turbine component having a higher-pressure region and a lower-pressure region, introducing particles into the higher-pressure region, and at least partially repairing an opening between the higher-pressure region and the lower-pressure region with at least one of the particles to form a repaired turbine component. The repaired coating includes a silicon material, a ceramic matrix composite material, and a repaired region having the silicon material deposited on and surrounded by the ceramic matrix composite material. The repaired turbine component a ceramic matrix composite layer and a repaired region having silicon material deposited on and surrounded by the ceramic matrix composite material.

  12. Time series evaluation of an intervention to increase statin tablet splitting by general practitioners.

    Science.gov (United States)

    Polinski, Jennifer M; Schneeweiss, Sebastian; Maclure, Malcolm; Marshall, Blair; Ramsden, Samuel; Dormuth, Colin

    2011-02-01

    Tablet splitting, in which a higher-dose tablet is split to get 2 doses, reduces patients' drug costs. Statins can be split safely. General practitioners (GPs) may not direct their patients to split statins because of safety concerns or unawareness of costs. Medical chart inserts provide cost-effective education to physicians. The aim of this study was to assess whether providing GPs with statin-splitting chart inserts would increase splitting rates, and to identify predictors of splitting. In 2005 and 2006, we faxed a statin chart insert to British Columbia GPs with a request for a telephone interview. Consenting GPs were mailed 3 statin chart inserts and interviewed by phone (the intervention). In an interrupted time series, we compared monthly rates of statin-splitting prescriptions among intervention and nonintervention GPs before, during, and after the intervention. In multivariate logistic regressions accounting for patient clustering, predictors of splitting included physician and patient demographics and the specific statin prescribed. Of 5051 GPs reached, 282 (6%) agreed to the intervention. Before the intervention, GPs' splitting rate was 2.6%; after intervention, GPs' splitting rate was 7.5%. The rate for the nonintervention GPs was 4.4%. Intervention GPs were 1.68 (95% CI, 1.12-2.53) times more likely to prescribe splitting after the intervention than were nonintervention GPs. Other predictors were a patient's female sex (odds ratio [OR] = 1.26; 95% CI, 1.18-1.34), lower patient income (OR = 1.33; 95% CI, 1.18-1.34), and a lack of drug insurance (OR = 1.89; 95% CI, 1.69-2.04). An inexpensive intervention was effective in producing a sustained increase in GPs' splitting rate during 22 months of observed follow-up. Expanding statin-splitting education to all GPs might reduce prescription costs for many patients and payors. Copyright © 2011 Elsevier HS Journals, Inc. All rights reserved.

  13. The toughness of split graphs

    NARCIS (Netherlands)

    Woeginger, G.J.

    1998-01-01

    In this short note we argue that the toughness of split graphs can be computed in polynomial time. This solves an open problem from a recent paper by Kratsch et al. (Discrete Math. 150 (1996) 231–245).

  14. ISR split-field magnet

    CERN Multimedia

    CERN PhotoLab

    1975-01-01

    The experimental apparatus used at intersection 4 around the Split-Field Magnet by the CERN-Bologna Collaboration (experiment R406). The plastic scintillator telescopes are used for precise pulse-height and time-of-flight measurements.

  15. Triadic split-merge sampler

    Science.gov (United States)

    van Rossum, Anne C.; Lin, Hai Xiang; Dubbeldam, Johan; van der Herik, H. Jaap

    2018-04-01

    In machine vision typical heuristic methods to extract parameterized objects out of raw data points are the Hough transform and RANSAC. Bayesian models carry the promise to optimally extract such parameterized objects given a correct definition of the model and the type of noise at hand. A category of solvers for Bayesian models are Markov chain Monte Carlo methods. Naive implementations of MCMC methods suffer from slow convergence in machine vision due to the complexity of the parameter space. Towards this blocked Gibbs and split-merge samplers have been developed that assign multiple data points to clusters at once. In this paper we introduce a new split-merge sampler, the triadic split-merge sampler, that perform steps between two and three randomly chosen clusters. This has two advantages. First, it reduces the asymmetry between the split and merge steps. Second, it is able to propose a new cluster that is composed out of data points from two different clusters. Both advantages speed up convergence which we demonstrate on a line extraction problem. We show that the triadic split-merge sampler outperforms the conventional split-merge sampler. Although this new MCMC sampler is demonstrated in this machine vision context, its application extend to the very general domain of statistical inference.

  16. Optimal field splitting for large intensity-modulated fields

    International Nuclear Information System (INIS)

    Kamath, Srijit; Sahni, Sartaj; Ranka, Sanjay; Li, Jonathan; Palta, Jatinder

    2004-01-01

    The multileaf travel range limitations on some linear accelerators require the splitting of a large intensity-modulated field into two or more adjacent abutting intensity-modulated subfields. The abutting subfields are then delivered as separate treatment fields. This workaround not only increases the treatment delivery time but it also increases the total monitor units (MU) delivered to the patient for a given prescribed dose. It is imperative that the cumulative intensity map of the subfields is exactly the same as the intensity map of the large field generated by the dose optimization algorithm, while satisfying hardware constraints of the delivery system. In this work, we describe field splitting algorithms that split a large intensity-modulated field into two or more intensity-modulated subfields with and without feathering, with optimal MU efficiency while satisfying the hardware constraints. Compared to a field splitting technique (without feathering) used in a commercial planning system, our field splitting algorithm (without feathering) shows a decrease in total MU of up to 26% on clinical cases and up to 63% on synthetic cases

  17. Flexural strength of structural concrete repaired with HBPMM cement

    International Nuclear Information System (INIS)

    Memon, G.H.; Khaskheli, G.B.; Kumar, A.

    2009-01-01

    To repair damaged concrete structures, Dadabhoy Cement Factory in Sindh has launched a product known as HBPMM (Hi-Bond Polymer Modified Mortar) cement. HBPMM is used to repair various concrete structures in Pakistan but the experimental back up regarding the real performance of the product, as far as flexural strength of concrete is concerned, is not well known yet. This study is thus aimed to investigate the flexural strength of structural concrete repaired with HBPMM compared to that repaired with OPC (Ordinary Portland Cement). In total 32 concrete beams (6x6x18) having compressive strength of 3000 and 5000 psi were manufactured. To obtain flexural strength of the beams, these were splitted by using a UTM (Universal Testing Machine). Beams were then repaired with different applications of HBPMM and OPC. After 28 days of curing, the repaired beams were re-splitted to determine the flexural strength of repaired beams. Results show that both HBPMM and OPC are not very effective. However, the performance of HBPMM remained slightly better than that of OPC. Both OPC and HBPMM remained more efficient in case of 5000 psi concrete than that of 3000 psi concrete. Flexural strength of repaired beams could be increased by increasing application of the repairing material. (author)

  18. Chronic radiation-induced leukemogenesis: alterations of hematopoietic progenitor repair functions during preclinical phases

    International Nuclear Information System (INIS)

    Seed, T.M.; Kaspar, L.V.; Grdina, D.J.; Frazier, M.E.

    1987-01-01

    Chronic exposure to low daily doses of whole-body gamma irradiation elicits a high incidence of myeloid leukemia (ML) and related myeloproliferative diseases (MPD) in beagles. Previously, the authors identified and partially characterized a four-phase sequence of evolving MPD as a consequence of chronic radiation exposure. With a focus on preclinical alterations in granulocyte/monocyte-committed stem cells, they have identified two critical events in the process: (i) an early event, involving the coupling of acquired radioresistance of the stem cell with renewed proliferative capacity; and (ii) a late event, involving acquired autocrine functions and associated change in stem cell clonality. In terms of the early event, repair-associated parameters are currently being examined on the cellular level by both split-dose and low dose-rate-type assays with survival enhancement used as the measured end point. On the molecular level, these parameters are examined by microfluorometric alkaline elution assays with DNA damage and repair used as end points

  19. Splitting: The Development of a Measure.

    Science.gov (United States)

    Gerson, Mary-Joan

    1984-01-01

    Described the development of a scale that measures splitting as a psychological structure. The construct validity of the splitting scale is suggested by the positive relationship between splitting scores and a diagnostic measure of the narcissistic personality disorder, as well as a negative relationship between splitting scores and levels of…

  20. Relationship of DNA repair processes to mutagenesis and carcinogenesis in mammalian cells. Progress report, November 1, 1980-October 31, 1981

    International Nuclear Information System (INIS)

    Evans, H.H.

    1981-10-01

    The isolation of several radiation-sensitive BHK strains following a host-cell viral suicide enrichment procedure has been reported in which mutagenized cells were infected with heavily irradiated Herpes virus (HSV). Six surviving colonies were isolated from 38,000 infected cells. The survivors were not transformed by HSV, as indicated by a lack of reaction with fluorescent HSV antibody. At least two of the strains were shown to be sensitive to the lethal effects of ionizing radiation and methylmethane sulfonate, but not to ethylmethane sulfonate (EMS) or to uv radiation. These two strains showed a small decrease in the ability to repair sublethal damage following a split dose of ionizing radiation. The two strains differed from wild-type BHK cells in EMS-induced mutability; strain VI showed a higher mutation frequency and V2 a lower mutation frequency than did BHK cells following treatment with this agent. When either ionizing radiation or uv radiation was used as the mutagenic agent, however, the comparative mutability patterns were altered: the mutation frequency of both strains was somewhat less than the wild type following ionizing radiation, whereas following uv radiation, strain V1 showed a markedly lower mutation frequency than the wild type. It is possible that the strain V1 is deficient in the repair of an EMS-induced mutagenic lesion, while strain V2 is either efficient in such repair or deficient in an error-prone repair process

  1. Split NMSSM with electroweak baryogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Demidov, S.V.; Gorbunov, D.S. [Institute for Nuclear Research of the Russian Academy of Sciences, 60th October Anniversary prospect 7a, Moscow 117312 (Russian Federation); Moscow Institute of Physics and Technology,Institutsky per. 9, Dolgoprudny 141700 (Russian Federation); Kirpichnikov, D.V. [Institute for Nuclear Research of the Russian Academy of Sciences, 60th October Anniversary prospect 7a, Moscow 117312 (Russian Federation)

    2016-11-24

    In light of the Higgs boson discovery and other results of the LHC we reconsider generation of the baryon asymmetry in the split Supersymmetry model with an additional singlet superfield in the Higgs sector (non-minimal split SUSY). We find that successful baryogenesis during the first order electroweak phase transition is possible within a phenomenologically viable part of the model parameter space. We discuss several phenomenological consequences of this scenario, namely, predictions for the electric dipole moments of electron and neutron and collider signatures of light charginos and neutralinos.

  2. Split ring containment attachment device

    International Nuclear Information System (INIS)

    Sammel, A.G.

    1996-01-01

    A containment attachment device is described for operatively connecting a glovebag to plastic sheeting covering hazardous material. The device includes an inner split ring member connected on one end to a middle ring member wherein the free end of the split ring member is inserted through a slit in the plastic sheeting to captively engage a generally circular portion of the plastic sheeting. A collar potion having an outer ring portion is provided with fastening means for securing the device together wherein the glovebag is operatively connected to the collar portion. 5 figs

  3. Splitting strings on integrable backgrounds

    Energy Technology Data Exchange (ETDEWEB)

    Vicedo, Benoit

    2011-05-15

    We use integrability to construct the general classical splitting string solution on R x S{sup 3}. Namely, given any incoming string solution satisfying a necessary self-intersection property at some given instant in time, we use the integrability of the worldsheet {sigma}-model to construct the pair of outgoing strings resulting from a split. The solution for each outgoing string is expressed recursively through a sequence of dressing transformations, the parameters of which are determined by the solutions to Birkhoff factorization problems in an appropriate real form of the loop group of SL{sub 2}(C). (orig.)

  4. Mass splitting induced by gravitation

    International Nuclear Information System (INIS)

    Maia, M.D.

    1982-08-01

    The exact combination of internal and geometrical symmetries and the associated mass splitting problem is discussed. A 10-parameter geometrical symmetry is defined in a curved space-time in such a way that it is a combination of de Sitter groups. In the flat limit it reproduces the Poincare-group and its Lie algebra has a nilpotent action on the combined symmetry only in that limit. An explicit mass splitting expression is derived and an estimation of the order of magnitude for spin-zero mesons is made. (author)

  5. Brain aneurysm repair

    Science.gov (United States)

    ... aneurysm repair; Dissecting aneurysm repair; Endovascular aneurysm repair - brain; Subarachnoid hemorrhage - aneurysm ... Your scalp, skull, and the coverings of the brain are opened. A metal clip is placed at ...

  6. Repairable-conditionally repairable damage model based on dual Poisson processes.

    Science.gov (United States)

    Lind, B K; Persson, L M; Edgren, M R; Hedlöf, I; Brahme, A

    2003-09-01

    The advent of intensity-modulated radiation therapy makes it increasingly important to model the response accurately when large volumes of normal tissues are irradiated by controlled graded dose distributions aimed at maximizing tumor cure and minimizing normal tissue toxicity. The cell survival model proposed here is very useful and flexible for accurate description of the response of healthy tissues as well as tumors in classical and truly radiobiologically optimized radiation therapy. The repairable-conditionally repairable (RCR) model distinguishes between two different types of damage, namely the potentially repairable, which may also be lethal, i.e. if unrepaired or misrepaired, and the conditionally repairable, which may be repaired or may lead to apoptosis if it has not been repaired correctly. When potentially repairable damage is being repaired, for example by nonhomologous end joining, conditionally repairable damage may require in addition a high-fidelity correction by homologous repair. The induction of both types of damage is assumed to be described by Poisson statistics. The resultant cell survival expression has the unique ability to fit most experimental data well at low doses (the initial hypersensitive range), intermediate doses (on the shoulder of the survival curve), and high doses (on the quasi-exponential region of the survival curve). The complete Poisson expression can be approximated well by a simple bi-exponential cell survival expression, S(D) = e(-aD) + bDe(-cD), where the first term describes the survival of undamaged cells and the last term represents survival after complete repair of sublethal damage. The bi-exponential expression makes it easy to derive D(0), D(q), n and alpha, beta values to facilitate comparison with classical cell survival models.

  7. Split supersymmetry in brane models

    Indian Academy of Sciences (India)

    Type-I string theory in the presence of internal magnetic fields provides a concrete realization of split ... quantum picture of the Universe. It was then ... where the integers m, n correspond to the respective magnetic and electric charges; m is the ...

  8. VBSCan Split 2017 Workshop Summary

    Energy Technology Data Exchange (ETDEWEB)

    Anders, Christoph Falk; et al.

    2018-01-12

    This document summarises the talks and discussions happened during the VBSCan Split17 workshop, the first general meeting of the VBSCan COST Action network. This collaboration is aiming at a consistent and coordinated study of vector-boson scattering from the phenomenological and experimental point of view, for the best exploitation of the data that will be delivered by existing and future particle colliders.

  9. Stability of split Stirling refrigerators

    NARCIS (Netherlands)

    Waele, de A.T.A.M.; Liang, W.

    2009-01-01

    In many thermal systems spontaneous mechanical oscillations are generated under the influence of large temperature gradients. Well-known examples are Taconis oscillations in liquid-helium cryostats and oscillations in thermoacoustic systems. In split Stirling refrigerators the compressor and the

  10. DNA repair , cell repair and radiosensitivity

    International Nuclear Information System (INIS)

    Zhestyanikov, V.D.

    1983-01-01

    Data obtained in laboratory of radiation cytology and literature data testifying to a considerable role of DNA repair in cell sensitivity to radiation and chemical DNA-tropic agents have been considered. Data pointing to the probability of contribution of inducible repair of DNA into plant cells sensitivity to X-rays are obtained. Certain violations of DNA repair do not result in the increase of radiosensitivity. It is assumed that in the cases unknown mechanisms of DNA repair operate

  11. Cool covered sky-splitting spectrum-splitting FK

    Energy Technology Data Exchange (ETDEWEB)

    Mohedano, Rubén; Chaves, Julio; Falicoff, Waqidi; Hernandez, Maikel; Sorgato, Simone [LPI, Altadena, CA, USA and Madrid (Spain); Miñano, Juan C.; Benitez, Pablo [LPI, Altadena, CA, USA and Madrid, Spain and Universidad Politécnica de Madrid (UPM), Madrid (Spain); Buljan, Marina [Universidad Politécnica de Madrid (UPM), Madrid (Spain)

    2014-09-26

    Placing a plane mirror between the primary lens and the receiver in a Fresnel Köhler (FK) concentrator gives birth to a quite different CPV system where all the high-tech components sit on a common plane, that of the primary lens panels. The idea enables not only a thinner device (a half of the original) but also a low cost 1-step manufacturing process for the optics, automatic alignment of primary and secondary lenses, and cell/wiring protection. The concept is also compatible with two different techniques to increase the module efficiency: spectrum splitting between a 3J and a BPC Silicon cell for better usage of Direct Normal Irradiance DNI, and sky splitting to harvest the energy of the diffuse radiation and higher energy production throughout the year. Simple calculations forecast the module would convert 45% of the DNI into electricity.

  12. Thymus repair compared with hemopoiesis repair in spleen after protracted irradiation

    International Nuclear Information System (INIS)

    Mackova, N.

    1987-01-01

    Matured female mice of ICR strain were irradiated from a 60 Co source with a daily dose rate of 5 Gy till total accumulated dose of 10 Gy for 2 days. Animals were examined in various intervals within 42 days after irradiation. The results revealed that protracted irradiation will induce a massive injury to hemopoiesis. The first repair processes occurred in thymus and were characterized by two phases. The first repair wave peaked about the day 10 and the second about the day 30 after irradiation. The repair processes observed in the red pulp of the spleen reached their highest intensity approximately between the days 14-16 after irradiation. (author)

  13. Tablet splitting of narrow therapeutic index drugs: a nationwide survey in Taiwan.

    Science.gov (United States)

    Chou, Chia-Lin; Hsu, Chia-Chen; Chou, Chia-Yu; Chen, Tzeng-Ji; Chou, Li-Fang; Chou, Yueh-Ching

    2015-12-01

    Tablet splitting or pill splitting frequently occurs in daily medical practice. For drugs with special pharmacokinetic characters, such as drugs with narrow therapeutic index (NTI), unequal split tablets might lead to erroneous dose titration and it even cause toxicity. The aim of this study was to investigate the frequency of prescribing split NTI drugs at ambulatory setting in Taiwan. A population-based retrospective study was conducted using the National Health Insurance Research Database in Taiwan. All ambulatory visits were analyzed from the longitudinal cohort datasets of the National Health Insurance Research Database. The details of ambulatory prescriptions containing NTI drugs were extracted by using the claims datasets of one million beneficiaries from National Healthcare Insurance Research Database in 2010 in Taiwan. The analyses were stratified by dosage form, patient age and the number of prescribed tablets in a single dose for each NTI drugs. Main outcome measures Number and distinct dosage forms of available NTI drug items in Taiwan, number of prescriptions involved split NTI drugs, and number of patients received split NTI drugs. A total of 148,548 patients had received 512,398 prescriptions of NTI drugs and 41.8 % (n = 62,121) of patients had received 36.3 % (n = 185,936) of NTI drug prescriptions in form of split tablets. The percentage of splitting was highest in digoxin prescriptions (81.0 %), followed by warfarin (72.0 %). In the elderly patients, split tablets were very prevalent with digoxin (82.4 %) and warfarin (84.5 %). NTI drugs were frequently prescribed to be taken in split forms in Taiwan. Interventions may be needed to provide effective and convenient NTI drug use. Further studies are needed to evaluate the clinical outcome of inappropriate split NTI drugs.

  14. Investigation of DNA damage and repair mechanism using deinococcus radiodurans

    International Nuclear Information System (INIS)

    Lau How Mooi; Kikuchi, M.; Kobayashi, Y.; Narumi, I.; Watanabe, H.

    1997-01-01

    Deninococcus Radiodurans, formerly known as Micrococcus Radiodurans, is a popular bacterium because of its high resistance to damage by carcinogens such as ionizing radiation (Dean et. al. 1966; Kitayama and Matsuyama 1968) and UV radiation (Gasvon et. al., 1995; Arrange et. al. 1993). In this report, we investigated the high resistance to ionizing radiation by this bacterium. The bacteria had been exposed from I to 5 kGy of gamma radiation and then incubated in TGY medium to study their ability to repair the broken DNA. The repair time was measured by Pulse Field Gel Electrophoresis (PFGE) method. The repair time for each dose was determined. Also in order to ensure that the repair was perfect, the bacterium was subjected to a second exposure of ionizing radiation after it has fully repaired. It was found that the 'second' repair characteristic was similar to the first repair. This confirmed that the repair after the exposure to the ionizing radiation was perfect

  15. Action of 50 R X-ray doses on the breeding function of C3H strain mice - effect of splitting the dose, action of repeated irradiations on successive generations; Action de 50 R de rayons X sur la fonction de reproduction des souris de race C3H - influence du fractionnement. Action de la repetition des irradiations au cours des generations successives

    Energy Technology Data Exchange (ETDEWEB)

    Alix, D [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1965-07-01

    X-rays exposure effect was studied on C3H strain mice, at the standpoint of the effects produced on breeding function. The method used with this purpose was the following: single doses 20 - 30 - 40 and 50 R/dose, fractional doses: 50 R/total dose, divided in 2 - 5 - 10 or 25 irradiations distributed in one month duration. The offsprings were irradiated at the same doses than the parents, consanguinity being maintained. Statistical treatment of results was carried out, that led at the following conclusions: 1) Couples receiving single exposure of 50 R or two exposures of 25 R at one month interval give comparable results. Fractional doses do not involve the slightest diminution of X-rays effect. 2) 30 R exposure brings about a decrease in fertility, with an increase in abortions. Fertility of 20 R irradiated couples remains below controls. 3) After ten times 5 R and twenty-five 2 R, the number of abortions is the largest. Ovarian function is particularly sensitive to X-rays; one may think that twenty-five 2 R give injuries conditioning non-viability of conception products, smaller doses should produce mutations and yield births of altered genotype individuals. (author) [French] L'action d'une exposition aux rayons X de souris de race C3H a ete etudiee du point de vue des effets produits sur la fonction reproductrice. La methode utilisee fut la suivante: doses administrees en irradiation unique: 20 - 30 - 40 et 50 R/seance, en irradiations fractionnees: 50 R au total en 2 - 5 - 10 ou 25 seances reparties en un mois. Les descendants ont ete irradies aux memes doses que leurs parents, en maintenant la consanguinite. Un traitement statistique des resultats a ete effectue dont on a pu conclure : 1) Chez les couples ayant recu une seule exposition de 50 R ou deux expositions de 25 R a intervalle d'un mois les resultats sont comparables. Le fractionnement n' entrainant aucune attenuation de l'action des rayons X. 2) Une exposition de 30 R entraine une baisse de fecondite

  16. Advanced repair methods for enhanced reactor safety

    International Nuclear Information System (INIS)

    Kornfeldt, H.

    1993-01-01

    A few innovative concepts are described of the ABB Atom Service Division for repair and mitigation techniques for primary systems in nuclear power plants. The concepts are based on Shape Memory Alloy (SMA) technology. A basic feature of all methods is that welding and component replacement is being avoided and the radiation dose imposed on maintenance personnel reduced. The SMA-based repair methods give plant operators new ways to meet increased safety standards and rising maintenance costs. (Z.S.) 4 figs

  17. Geometrical Applications of Split Octonions

    Directory of Open Access Journals (Sweden)

    Merab Gogberashvili

    2015-01-01

    Full Text Available It is shown that physical signals and space-time intervals modeled on split-octonion geometry naturally exhibit properties from conventional (3 + 1-theory (e.g., number of dimensions, existence of maximal velocities, Heisenberg uncertainty, and particle generations. This paper demonstrates these properties using an explicit representation of the automorphisms on split-octonions, the noncompact form of the exceptional Lie group G2. This group generates specific rotations of (3 + 4-vector parts of split octonions with three extra time-like coordinates and in infinitesimal limit imitates standard Poincare transformations. In this picture translations are represented by noncompact Lorentz-type rotations towards the extra time-like coordinates. It is shown how the G2 algebra’s chirality yields an intrinsic left-right asymmetry of a certain 3-vector (spin, as well as a parity violating effect on light emitted by a moving quantum system. Elementary particles are connected with the special elements of the algebra which nullify octonionic intervals. Then the zero-norm conditions lead to free particle Lagrangians, which allow virtual trajectories also and exhibit the appearance of spatial horizons governing by mass parameters.

  18. 2-Photon tandem device for water splitting

    DEFF Research Database (Denmark)

    Seger, Brian; Castelli, Ivano Eligio; Vesborg, Peter Christian Kjærgaard

    2014-01-01

    Within the field Of photocatalytic water splitting there are several strategies to achieve the goal of efficient and cheap photocatalytic water splitting. This work examines one particular strategy by focusing on monolithically stacked, two-photon photoelectrochemical cells. The overall aim...... for photocatalytic water splitting by using a large bandgap photocathode and a low bandgap photoanode with attached protection layers....

  19. The time course of repair of ultraviolet-induced DNA damage; implications for the structural organization of repair

    International Nuclear Information System (INIS)

    Collins, A.; Squires, S.

    1986-01-01

    Alternative molecular mechanisms can be envisaged for the cellular repair of UV-damaged DNA. In the 'random collision' model, DNA damage distributed throughout the genome is recognised and repaired by a process of random collision between DNA damage and repair enzymes. The other model assumes a 'processive' mechanism, whereby DNA is scanned for damage by a repair complex moving steadily along its length. Random collision should result in a declining rate of repair with time as the concentration of lesions in the DNA falls; but the processive model predicts a constant rate until scanning is complete. The authors have examined the time course of DNA repair in human fibroblasts given low doses of UV light. Using 3 distinct assays, the authors find no sign of a constant repair rate after 4 J/m 2 or less, even when the first few hours after irradiation are examined. Thus DNA repair is likely to depend on random collision. (Auth.)

  20. UVA-induced DNA double-strand breaks result from the repair of clustered oxidative DNA damages

    Science.gov (United States)

    Greinert, R.; Volkmer, B.; Henning, S.; Breitbart, E. W.; Greulich, K. O.; Cardoso, M. C.; Rapp, Alexander

    2012-01-01

    UVA (320–400 nm) represents the main spectral component of solar UV radiation, induces pre-mutagenic DNA lesions and is classified as Class I carcinogen. Recently, discussion arose whether UVA induces DNA double-strand breaks (dsbs). Only few reports link the induction of dsbs to UVA exposure and the underlying mechanisms are poorly understood. Using the Comet-assay and γH2AX as markers for dsb formation, we demonstrate the dose-dependent dsb induction by UVA in G1-synchronized human keratinocytes (HaCaT) and primary human skin fibroblasts. The number of γH2AX foci increases when a UVA dose is applied in fractions (split dose), with a 2-h recovery period between fractions. The presence of the anti-oxidant Naringin reduces dsb formation significantly. Using an FPG-modified Comet-assay as well as warm and cold repair incubation, we show that dsbs arise partially during repair of bi-stranded, oxidative, clustered DNA lesions. We also demonstrate that on stretched chromatin fibres, 8-oxo-G and abasic sites occur in clusters. This suggests a replication-independent formation of UVA-induced dsbs through clustered single-strand breaks via locally generated reactive oxygen species. Since UVA is the main component of solar UV exposure and is used for artificial UV exposure, our results shine new light on the aetiology of skin cancer. PMID:22941639

  1. On the effect of small radiation doses: Desoxyribonucleic acid (DNA) synthesis and DNA repair of thymus, spleen, and bone marrow cells in the rat after fractionated total body X-ray irradiation. Zur Wirkung kleiner Strahlendosen: Desoxyribonukleinsaeure-(DNA-)Synthese und DNA-Reparatur von Thymus-, Milz- und Knochenmarkszellen der Ratte nach fraktionierter Ganzkoerperroentgenbestrahlung

    Energy Technology Data Exchange (ETDEWEB)

    Tempel, K.; Ehling, G. (Muenchen Univ. (Germany, F.R.). Inst. fuer Pharmakologie, Toxikologie und Pharmazie)

    1989-09-01

    After three to seven days following to fractionated total body X-ray irradiation (TBI) (four expositions with doses of 0.3 to 5.0 cGy per fraction at intervals of 24 hours), a maximum 50 percent stimulation of the semiconservative DNA synthesis (SDS) of spleen cells was measured in vitro. This was not dependent of the fact if an acute high-dose (400 and/or 800 cGy) unique irradiation was applied after the fractionated TBI at the moment of stimulation. A significant increase of {sup 3}H-thymidine incorporation into the DNA of bone marrow and thymus cells was only found when doses of 1.25 cGy per fraction had been used. After fractionated TBI with doses of {ge}5 cGy per fraction, an increase of DNA synthesis resistant to hydroxyurea ('unprogrammed' DNA synthesis, UDS) was demonstrated in spleen cells. The UV-simulated UDS decreased proportionately. The sedimentation of thymus, spleen, and bone marrow nucleoids in a neutral saccharose gradient gave no evidence of an increased DNA repair capacity after fractionated TBI. Whereas the SDS stimulation by fractionated TBI with small doses can be explained by a modified proliferation behavior of exposed cells, the UDS behavior of spleen cells after considerably higher radiation doses suggests regenerative processes correlated with an increased number of cells resistant to hydroxyurea and cells presenting an UV repair deficiency. These findings can be considered to be a further proof of the assumed immune-stimulating effect of small radiation doses. (orig.).

  2. Innovative wedge axe in making split firewood

    International Nuclear Information System (INIS)

    Mutikainen, A.

    1998-01-01

    Interteam Oy, a company located in Espoo, has developed a new method for making split firewood. The tools on which the patented System Logmatic are based are wedge axe and cylindrical splitting-carrying frame. The equipment costs about 495 FIM. The block of wood to be split is placed inside the upright carrying frame and split in a series of splitting actions using the innovative wedge axe. The finished split firewood remains in the carrying frame, which (as its name indicates) also serves as the means for carrying the firewood. This innovative wedge-axe method was compared with the conventional splitting of wood using an axe (Fiskars -handy 1400 splitting axe costing about 200 FIM) in a study conducted at TTS-Institute. There were eight test subjects involved in the study. In the case of the wedge-axe method, handling of the blocks to be split and of the finished firewood was a little quicker, but in actual splitting it was a little slower than the conventional axe method. The average productivity of splitting the wood and of the work stages related to it was about 0.4 m 3 per effective hour in both methods. The methods were also equivalent of one another in terms of the load imposed by the work when measured in terms of the heart rate. As regards work safety, the wedge-axe method was superior to the conventional method, but the continuous striking action and jolting transmitted to the arms were unpleasant (orig.)

  3. Rapid road repair vehicle

    Science.gov (United States)

    Mara, Leo M.

    1998-01-01

    Disclosed is a rapid road repair vehicle capable of moving over a surface to be repaired at near normal posted traffic speeds to scan for and find an the high rate of speed, imperfections in the pavement surface, prepare the surface imperfection for repair by air pressure and vacuum cleaning, applying a correct amount of the correct patching material to effect the repair, smooth the resulting repaired surface, and catalog the location and quality of the repairs for maintenance records of the road surface. The rapid road repair vehicle can repair surface imperfections at lower cost, improved quality, at a higher rate of speed than was was heretofor possible, with significantly reduced exposure to safety and health hazards associated with this kind of road repair activities in the past.

  4. Effects of low doses

    International Nuclear Information System (INIS)

    Le Guen, B.

    2001-01-01

    Actually, even though it is comfortable for the risk management, the hypothesis of the dose-effect relationship linearity is not confirmed for any model. In particular, in the area of low dose rate delivered by low let emitters. this hypothesis is debated at the light of recent observations, notably these ones relative to the mechanisms leading to genetic instability and induction eventuality of DNA repair. The problem of strong let emitters is still to solve. (N.C.)

  5. A typology of split conjunction

    OpenAIRE

    Palancar , Enrique L.

    2012-01-01

    International audience; In this paper, I study instances of noun phrase conjunction where the conjoined noun phrase is subject and the referents of the conjuncts are human, of the type ‘John and Mary are having lunch’. More specifically, I study different, possible splits that occur in such structures, which involve the disruption of the phrasal continuity of the conjuncts, resulting in structures roughly equivalent to ‘they are having lunch with Mary’ and ‘John are having lunch with Mary’. I...

  6. Effect of split n fertilizer application on physio-agronomic traits of wheat (triticum aestivum l.) under rainfed conditions

    International Nuclear Information System (INIS)

    Sohail, M.; Hussain, I.; Din, R.U.; Haider, S.; Abbas, A.; Qamar, M.; Noman, M.

    2013-01-01

    Low soil fertility is one of the main wheat yield limiting factors under rainfed conditions. Farmers usually apply full N dose at seeding. However, winter showers during vegetative growth period provide an opportunity to apply N in split doses. Study was conducted to find out appropriate N rate and application method to enhance wheat productivity. -1 Three N rates i.e., 60, 90, and 120 kg ha and three application methods i.e. full basal N dose at planting and N application in two and three equal split doses at tiller formation and stem elongation stages. Maximum grain yield (5.20 t ha/sup -1/) was achieved when N was applied at the rate 120 kg ha in three equal split doses at planting, tiller formation and stem elongation stages. N application in 2 and 3 split doses resulted in 25 - 50% grain yield advantage at all N rates as compared to single basal N dose. Split N application was associated with significant increase (P<0.05) in spikes m, 1000 grain weight and dry matter production. Split N application was also linked with better flag leaf chlorophyll retention and cooler crop canopies during grain filling stages which showed positive association with grain yield. (author)

  7. Time-dependent Reliability of Dynamic Systems using Subset Simulation with Splitting over a Series of Correlated Time Intervals

    Science.gov (United States)

    2013-08-01

    cost due to potential warranty costs, repairs and loss of market share. Reliability is the probability that the system will perform its intended...MCMC and splitting sampling schemes. Our proposed SS/ STP method is presented in Section 4, including accuracy bounds and computational effort

  8. Repair of radiation damage in mammalian cells

    Energy Technology Data Exchange (ETDEWEB)

    Setlow, R.B.

    1981-01-01

    The responses, such as survival, mutation, and carcinogenesis, of mammalian cells and tissues to radiation are dependent not only on the magnitude of the damage to macromolecular structures - DNA, RNA, protein, and membranes - but on the rates of macromolecular syntheses of cells relative to the half-lives of the damages. Cells possess a number of mechanisms for repairing damage to DNA. If the repair systems are rapid and error free, cells can tolerate much larger doses than if repair is slow or error prone. It is important to understand the effects of radiation and the repair of radiation damage because there exist reasonable amounts of epidemiological data that permits the construction of dose-response curves for humans. The shapes of such curves or the magnitude of the response will depend on repair. Radiation damage is emphasized because: (a) radiation dosimetry, with all its uncertainties for populations, is excellent compared to chemical dosimetry; (b) a number of cancer-prone diseases are known in which there are defects in DNA repair and radiation results in more chromosomal damage in cells from such individuals than in cells from normal individuals; (c) in some cases, specific radiation products in DNA have been correlated with biological effects, and (d) many chemical effects seem to mimic radiation effects. A further reason for emphasizing damage to DNA is the wealth of experimental evidence indicating that damages to DNA can be initiating events in carcinogenesis.

  9. Repair of radiation damage in mammalian cells

    International Nuclear Information System (INIS)

    Setlow, R.B.

    1981-01-01

    The responses, such as survival, mutation, and carcinogenesis, of mammalian cells and tissues to radiation are dependent not only on the magnitude of the damage to macromolecular structures - DNA, RNA, protein, and membranes - but on the rates of macromolecular syntheses of cells relative to the half-lives of the damages. Cells possess a number of mechanisms for repairing damage to DNA. If the repair systems are rapid and error free, cells can tolerate much larger doses than if repair is slow or error prone. It is important to understand the effects of radiation and the repair of radiation damage because there exist reasonable amounts of epidemiological data that permits the construction of dose-response curves for humans. The shapes of such curves or the magnitude of the response will depend on repair. Radiation damage is emphasized because: (a) radiation dosimetry, with all its uncertainties for populations, is excellent compared to chemical dosimetry; (b) a number of cancer-prone diseases are known in which there are defects in DNA repair and radiation results in more chromosomal damage in cells from such individuals than in cells from normal individuals; (c) in some cases, specific radiation products in DNA have been correlated with biological effects, and (d) many chemical effects seem to mimic radiation effects. A further reason for emphasizing damage to DNA is the wealth of experimental evidence indicating that damages to DNA can be initiating events in carcinogenesis

  10. Collision Repair Campaign

    Science.gov (United States)

    The Collision Repair Campaign targets meaningful risk reduction in the Collision Repair source category to reduce air toxic emissions in their communities. The Campaign also helps shops to work towards early compliance with the Auto Body Rule.

  11. Retinal detachment repair

    Science.gov (United States)

    ... medicines Problems breathing You may not recover full vision. ... detachments can be repaired. Failure to repair the retina always results in loss of vision to some degree. After surgery, the quality of ...

  12. Piezosurgery for the repair of middle cranial fossa meningoencephaloceles.

    Science.gov (United States)

    Acharya, Aanand N; Rajan, Gunesh P

    2015-03-01

    To describe the use of a piezosurgery medical device to perform a craniotomy and produce a split calvarial graft for the repair of middle cranial fossa meningoencephaloceles. Retrospective case review. Tertiary referral hospital. Ten consecutive patients undergoing middle cranial fossa approach for the repair of meningoencephaloceles. Therapeutic. Intraoperative and postoperative complications, success rate as defined by the ability to fashion a split calvarial graft that achieves complete closure of the tegmen defect. As a secondary outcome measure, evidence of integration of the split calvarial bone graft with the adjacent skull base was assessed. There were no intraoperative or postoperative complications. An appropriately sized calvarial bone graft was produced, and complete closure of the tegmen defect was achieved in all 10 cases. Computed tomography demonstrated evidence of integration of the bone graft in eight cases between 4 and 9 months after surgery. The piezosurgery medical device provides a safe and effective means by which the middle fossa craniotomy and split calvarial bone graft can be produced to repair defects of the middle fossa tegmen, with integration of the bone graft in the majority of cases.

  13. Algebraic techniques for diagonalization of a split quaternion matrix in split quaternionic mechanics

    International Nuclear Information System (INIS)

    Jiang, Tongsong; Jiang, Ziwu; Zhang, Zhaozhong

    2015-01-01

    In the study of the relation between complexified classical and non-Hermitian quantum mechanics, physicists found that there are links to quaternionic and split quaternionic mechanics, and this leads to the possibility of employing algebraic techniques of split quaternions to tackle some problems in complexified classical and quantum mechanics. This paper, by means of real representation of a split quaternion matrix, studies the problem of diagonalization of a split quaternion matrix and gives algebraic techniques for diagonalization of split quaternion matrices in split quaternionic mechanics

  14. Repair of double-strand breaks in Micrococcus radiodurans

    International Nuclear Information System (INIS)

    Burrell, A.D.; Dean, C.J.

    1975-01-01

    Micrococcus radiodurans has been shown to sustain double-strand breaks in its DNA after exposure to x-radiation. Following sublethal doses of x-rays (200 krad in oxygen or less), the cells were able to repair these breaks, and an intermediate fast-sedimenting DNA component seemed to be involved in the repair process

  15. Additive operator-difference schemes splitting schemes

    CERN Document Server

    Vabishchevich, Petr N

    2013-01-01

    Applied mathematical modeling isconcerned with solving unsteady problems. This bookshows how toconstruct additive difference schemes to solve approximately unsteady multi-dimensional problems for PDEs. Two classes of schemes are highlighted: methods of splitting with respect to spatial variables (alternating direction methods) and schemes of splitting into physical processes. Also regionally additive schemes (domain decomposition methods)and unconditionally stable additive schemes of multi-component splitting are considered for evolutionary equations of first and second order as well as for sy

  16. Iterative Splitting Methods for Differential Equations

    CERN Document Server

    Geiser, Juergen

    2011-01-01

    Iterative Splitting Methods for Differential Equations explains how to solve evolution equations via novel iterative-based splitting methods that efficiently use computational and memory resources. It focuses on systems of parabolic and hyperbolic equations, including convection-diffusion-reaction equations, heat equations, and wave equations. In the theoretical part of the book, the author discusses the main theorems and results of the stability and consistency analysis for ordinary differential equations. He then presents extensions of the iterative splitting methods to partial differential

  17. Radiation repair models for clinical application.

    Science.gov (United States)

    Dale, Roger G

    2018-02-28

    A number of newly emerging clinical techniques involve non-conventional patterns of radiation delivery which require an appreciation of the role played by radiation repair phenomena. This review outlines the main models of radiation repair, focussing on those which are of greatest clinical usefulness and which may be incorporated into biologically effective dose assessments. The need to account for the apparent "slowing-down" of repair rates observed in some normal tissues is also examined, along with a comparison of the relative merits of the formulations which can be used to account for such phenomena. Jack Fowler brought valuable insight to the understanding of radiation repair processes and this article includes reference to his important contributions in this area.

  18. A new barbed device for repair of flexor tendons.

    LENUS (Irish Health Repository)

    Hirpara, K M

    2012-02-01

    We split 100 porcine flexor tendons into five groups of 20 tendons for repair. Three groups were repaired using the Pennington modified Kessler technique, the cruciate or the Savage technique, one using one new device per tendon and the other with two new devices per tendon. Half of the tendons received supplemental circumferential Silfverskiold type B cross-stitch. The repairs were loaded to failure and a record made of their bulk, the force required to produce a 3 mm gap, the maximum force applied before failure and the stiffness. When only one device was used repairs were equivalent to the Pennington modified Kessler for all parameters except the force to produce a 3 mm gap when supplemented with a circumferential repair, which was equivalent to the cruciate. When two devices were used the repair strength was equivalent to the cruciate repair, and when the two-device repair was supplemented with a circumferential suture the force to produce a 3 mm gap was equivalent to that of the Savage six-strand technique.

  19. Dark matter from split seesaw

    International Nuclear Information System (INIS)

    Kusenko, Alexander; Takahashi, Fuminobu; Yanagida, Tsutomu T.

    2010-01-01

    The seesaw mechanism in models with extra dimensions is shown to be generically consistent with a broad range of Majorana masses. The resulting democracy of scales implies that the seesaw mechanism can naturally explain the smallness of neutrino masses for an arbitrarily small right-handed neutrino mass. If the scales of the seesaw parameters are split, with two right-handed neutrinos at a high scale and one at a keV scale, one can explain the matter-antimatter asymmetry of the universe, as well as dark matter. The dark matter candidate, a sterile right-handed neutrino with mass of several keV, can account for the observed pulsar velocities and for the recent data from Chandra X-ray Observatory, which suggest the existence of a 5 keV sterile right-handed neutrino.

  20. Photon-splitting cross sections

    International Nuclear Information System (INIS)

    Johannessen, A.M.; Mork, K.J.; Overbo, I.

    1980-01-01

    The differential cross section for photon splitting (scattering of one photon into two photons) in a Coulomb field, obtained earlier by Shima, has been integrated numerically to yield various differential cross sections. Energy spectra differential with respect to the energy of one of the outgoing photons are presented for several values of the primary photon energy. Selected examples of recoil momentum distributions and some interesting doubly or multiply differential cross sections are also given. Values for the total cross section are obtained essentially for all energies. The screening effect caused by atomic electrons is also taken into account, and is found to be important for high energies, as in e + e - pair production. Comparisons with various approximate results obtained by previous authors mostly show fair agreement. We also discuss the possibilities for experimental detection and find the most promising candidate to be a measurement of both photons, and their energies, at a moderately high energy

  1. Gauge mediated mini-split

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, Timothy [Institute of Theoretical Science, University of Oregon,Eugene, OR 97403 (United States); Craig, Nathaniel [Department of Physics, University of California,Santa Barbara, CA 93106 (United States); Knapen, Simon [Berkeley Center for Theoretical Physics,University of California, Berkeley, CA 94720 (United States); Theoretical Physics Group,Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

    2016-03-15

    We propose a simple model of split supersymmetry from gauge mediation. This model features gauginos that are parametrically a loop factor lighter than scalars, accommodates a Higgs boson mass of 125 GeV, and incorporates a simple solution to the μ−b{sub μ} problem. The gaugino mass suppression can be understood as resulting from collective symmetry breaking. Imposing collider bounds on μ and requiring viable electroweak symmetry breaking implies small a-terms and small tan β — the stop mass ranges from 10{sup 5} to 10{sup 8} GeV. In contrast with models with anomaly + gravity mediation (which also predict a one-loop loop suppression for gaugino masses), our gauge mediated scenario predicts aligned squark masses and a gravitino LSP. Gluinos, electroweakinos and Higgsinos can be accessible at the LHC and/or future colliders for a wide region of the allowed parameter space.

  2. Salt splitting with ceramic membranes

    International Nuclear Information System (INIS)

    Kurath, D.

    1996-01-01

    The purpose of this task is to develop ceramic membrane technologies for salt splitting of radioactively contaminated sodium salt solutions. This technology has the potential to reduce the low-level waste (LLW) disposal volume, the pH and sodium hydroxide content for subsequent processing steps, the sodium content of interstitial liquid in high-level waste (HLW) sludges, and provide sodium hydroxide free of aluminum for recycle within processing plants at the DOE complex. Potential deployment sites include Hanford, Savannah River, and Idaho National Engineering Laboratory (INEL). The technical approach consists of electrochemical separation of sodium ions from the salt solution using sodium (Na) Super Ion Conductors (NaSICON). As the name implies, sodium ions are transported rapidly through these ceramic crystals even at room temperatures

  3. Splitting tests on rock specimens

    Energy Technology Data Exchange (ETDEWEB)

    Davies, J D; Stagg, K G

    1970-01-01

    Splitting tests are described for a square-section sandstone specimens line loaded through steel or timber packings on the top face and supported on the bottom face either on similar packings (type A specimen) or directly on the lower platen plate of the testing machine (type B specimens). The stress distribution across the vertical central plane and the horizontal central plane were determined from a linear elastic finite element analysis for both types. Two solutions were obtained for the type B specimen: one assuming no friction between the base of the specimen and the platen plate and the other assuming no relative slip between the surfaces. Vertical and horizontal strains were measured at the center of the specimens for all loads up to failure.

  4. Split supersymmetry in unified models

    International Nuclear Information System (INIS)

    Dutta, Bhaskar; Mimura, Yukihiro

    2005-01-01

    In the context of split supersymmetry, the gaugino mass spectrum seems to be very important to satisfy the dark matter content of the universe and the gauge coupling unification. In this Letter, we have considered various sources of gaugino masses in the context of unified models. We show that the gaugino mass spectrum varies in different unification pictures. In the context of SU(5), we have found that the bino/wino mass ratio can be close to one at the weak scale which is helpful to satisfy the WMAP data. The gluino/wino mass ratio is also different from the usual scenario of unified gaugino masses. The gaugino masses can be around one TeV and m SUSY is chosen so that the gluino mass does not create any cosmological problem. In the context of the Pati-Salam model, we show that the gluino mass can be made very heavy even after maintaining the unification of the gauge couplings

  5. Spin Splitting in Different Semiconductor Quantum Wells

    International Nuclear Information System (INIS)

    Hao Yafei

    2012-01-01

    We theoretically investigate the spin splitting in four undoped asymmetric quantum wells in the absence of external electric field and magnetic field. The quantum well geometry dependence of spin splitting is studied with the Rashba and the Dresselhaus spin-orbit coupling included. The results show that the structure of quantum well plays an important role in spin splitting. The Rashba and the Dresselhaus spin splitting in four asymmetric quantum wells are quite different. The origin of the distinction is discussed in this work. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  6. Oligodendroglial response to ionizing radiation: Dose and dose-rate response

    International Nuclear Information System (INIS)

    Levy, R.P.

    1991-01-01

    An in vitro system using neuroglia from neonatal rat brain was developed to examining the morphologic, immunocytochemical and biochemical response of oligodendroglia to ionizing radiation. Following acute γ-radiation at day-in-culture (DIC) 8, oligodendrocyte counts at DIC 14 were 55% to 65% of control values after 2 Gy, and 29% to 36% after 5 Gy. Counts increased to near-normal levels at DIC 21 in the 2 Gy group and to 75% of normal in the 5 Gy group. Myelin basic protein levels (MBP) at DIC 14 were 60% of control values after 2 Gy, and 40% after 5 Gy. At DIC 21, MBP after 2 Gy was 45% greater than that observed at DIC 14, but MBP, as a fraction of age-matched control values, dropped from 60% to 50%. Following 5 Gy, absolute MBP changed little between DIC 14 and DIC 21, but decreased from 40% to 25% of control cultures. It was concluded that oligodendrocytes in irradiated cultures had significantly lower functional capacity than did unirradiated controls. The response to split-dose irradiation indicated that nearly all sublethal damage in the oligodendrocyte population (and its precursors) was repaired within 3 h to 4 h. At DIC 14, the group irradiated in a single fraction had significantly lower oligodendrocyte counts than any group given split doses; all irradiated cultures had marked depression of MBP synthesis, but to significant differences referable to time interval between doses. At DIC 21, cultures irradiated at intervals of 0 h to 2 h had similar oligodendrocyte counts to one another, but these counts were significantly lower than in cultures irradiated at intervals of 4 h to 6 h; MBP levels remained depressed at DIC 21 for all irradiated cultures. The oligodendrocyte response to dose rate (0.03 to 1.97 Gy/min) was evaluated at DIC 14 and DIC 21. Exposure at 0.03 Gy/min suppressed oligodendrocyte counts at DIC 21 less than did higher dose rates in 5-Gy irradiated cultures

  7. In Situ Splitting of a Rib Bone Graft for Reconstruction of Orbital Floor and Medial Wall.

    Science.gov (United States)

    Uemura, Tetsuji; Yanai, Tetsu; Yasuta, Masato; Harada, Yoshimi; Morikawa, Aya; Watanabe, Hidetaka; Kurokawa, Masato

    2017-06-01

    In situ splitting of rib bone graft was conducted in 22 patients for the repair of orbital fracture with no other complicating fractures. A bone graft was harvested from the sixth or seventh rib in the right side. The repair of the orbital floor and medial wall was successful in all the cases. Ten patients had bone grafting to the orbital floor, eight had it done onto medial wall, and 4 onto both floor and wall after reduction. The mean length of in situ rib bone graft was 40.9 mm (range, 20-70 mm), the mean width of these was 14.9 mm (range, 8-20 mm). The bone grafting was done by one leaf for 15 cases and two leafs for 7 cases in size of defects. The technique of in situ splitting of a rib bone graft for the repair of the orbital floor and medial wall is a simple and safe procedure, easily taking out the in situ splitting of a rib, and less pain in donor site. It has proved to be an optimal choice in craniofacial reconstruction, especially the defects of orbital floor and medial wall.

  8. Salt splitting using ceramic membranes

    Energy Technology Data Exchange (ETDEWEB)

    Kurath, D.E. [Pacific Northwest National Lab., Richland, WA (United States)

    1997-10-01

    Many radioactive aqueous wastes in the DOE complex have high concentrations of sodium that can negatively affect waste treatment and disposal operations. Sodium can decrease the durability of waste forms such as glass and is the primary contributor to large disposal volumes. Waste treatment processes such as cesium ion exchange, sludge washing, and calcination are made less efficient and more expensive because of the high sodium concentrations. Pacific Northwest National Laboratory (PNNL) and Ceramatec Inc. (Salt Lake City UT) are developing an electrochemical salt splitting process based on inorganic ceramic sodium (Na), super-ionic conductor (NaSICON) membranes that shows promise for mitigating the impact of sodium. In this process, the waste is added to the anode compartment, and an electrical potential is applied to the cell. This drives sodium ions through the membrane, but the membrane rejects most other cations (e.g., Sr{sup +2}, Cs{sup +}). The charge balance in the anode compartment is maintained by generating H{sup +} from the electrolysis of water. The charge balance in the cathode is maintained by generating OH{sup {minus}}, either from the electrolysis of water or from oxygen and water using an oxygen cathode. The normal gaseous products of the electrolysis of water are oxygen at the anode and hydrogen at the cathode. Potentially flammable gas mixtures can be prevented by providing adequate volumes of a sweep gas, using an alternative reductant or destruction of the hydrogen as it is generated. As H{sup +} is generated in the anode compartment, the pH drops. The process may be operated with either an alkaline (pH>12) or an acidic anolyte (pH <1). The benefits of salt splitting using ceramic membranes are (1) waste volume reduction and reduced chemical procurement costs by recycling of NaOH; and (2) direct reduction of sodium in process streams, which enhances subsequent operations such as cesium ion exchange, calcination, and vitrification.

  9. DNA repair and its coupling to DNA replication in eukaryotic cells. [UV, x ray

    Energy Technology Data Exchange (ETDEWEB)

    Cleaver, J.E.

    1978-01-01

    This review article with 184 references presents the view that mammalian cells have one major repair system, excision repair, with many branches (nucleotide excision repair, base excision repair, crosslink repair, etc.) and a multiplicity of enzymes. Any particular carcinogen makes a spectrum of damaged sites and each kind of damage may be repaired by one or more branches of excision repair. Excision repair is rarely complete, except at very low doses, and eukaryotic cells survive and replicate DNA despite the presence of unrepaired damage. An alteration in a specific biochemical pathway seen in damaged or mutant cells will not always be the primary consequence of damage or of the biochemical defect of the cells. Detailed kinetic data are required to understand comprehensively the various facets of excision repair and replication. Correlation between molecular events of repair and cytological and cellular changes such as chromosomal damage, mutagenesis, transformation, and carcinogenesis are also rudimentary.

  10. DNA damage repair and radiosensitivity

    International Nuclear Information System (INIS)

    Suzuki, Norio

    2003-01-01

    Tailored treatment is not new in radiotherapy; it has been the major subject for the last 20-30 years. Radiation responses and RBE (relative biological effectiveness) depend on assay systems, endpoints, type of tissues and tumors, radiation quality, dose rate, dose fractionation, physiological and environmental factors etc, Latent times to develop damages also differ among tissues and endpoints depending on doses and radiation quality. Recent progress in clarification of radiation induced cell death, especially of apoptotic cell death, is quite important for understanding radiosensitivity of tumor cure process as well as of tumorigenesis. Apoptotic cell death as well as dormant cells had been unaccounted and missed into a part of reproductive cell death. Another area of major progress has been made in clarifying repair mechanisms of radiation damage, i.e., non-homologous end joining (NHEJ) and homologous recombinational repair (HRR). New approaches and developments such as cDNA or protein micro arrays and so called informatics in addition to basic molecular biological analysis are expected to aid identifying molecules and their roles in signal transduction pathways, which are multi-factorial and interactive each other being involved in radiation responses. (authors)

  11. SplitDist—Calculating Split-Distances for Sets of Trees

    DEFF Research Database (Denmark)

    Mailund, T

    2004-01-01

    We present a tool for comparing a set of input trees, calculating for each pair of trees the split-distances, i.e., the number of splits in one tree not present in the other.......We present a tool for comparing a set of input trees, calculating for each pair of trees the split-distances, i.e., the number of splits in one tree not present in the other....

  12. Molecular concepts of water splitting. Nature's approach

    Energy Technology Data Exchange (ETDEWEB)

    Cox, Nicholas; Lubitz, Wolfgang [Max-Planck-Institut fuer Chemische Energiekonversion, Muelheim an der Ruhr (Germany)

    2013-07-01

    Based on studies of natural systems, much has also been learned concerning the design principles required for biomimetic catalysis of water splitting and hydrogen evolution. In summary, these include use of abundant and inexpensive metals, the effective protection of the active sites in functional environments, repair/replacement of active components in case of damage, and the optimization of reaction rates. Biomimetic chemistry aims to mimic all these features; many labs are working toward this goal by developing new approaches in the design and synthesis of such systems, encompassing not only the catalytic center, but also smart matrices and assembly via self-organization. More stable catalysts that do not require self-repair may be obtained from fully artificial (inorganic) catalytic systems that are totally different from the biological ones and only apply some basic principles learned from nature. Metals other than Mn/Ca, Fe, and Ni could be used (e.g. Co) in new ligand spheres and other matrices. For light harvesting, charge separation/stabilization, and the effective coupling of the oxidizing/reducing equivalents to the redox catalysts, different methods have been proposed - for example, covalently linked molecular donor-acceptor systems, photo-voltaic devices, semiconductor-based systems, and photoactive metal complexes. The aim of all these approaches is to develop catalytic systems that split water with sunlight into hydrogen and oxygen while displaying high efficiency and long-term stability. Such a system - either biological, biomimetic, or bioinspired - has the potential to be used on a large scale to produce 'solar fuels' (e.g. hydrogen or secondary products thereof). (orig.)

  13. The effect of postirradiation holding at 22 degrees C on the repair of sublethal, potentially lethal and potentially neoplastic transforming damage in gamma-irradiated HeLa x skin fibroblast human hybrid cells

    International Nuclear Information System (INIS)

    Redpath, J.L.; Antoniono, R.J.; Mendonca, M.S.; Sun, C.

    1994-01-01

    The effect of postirradiation holding at 22 degrees C on cell growth, progression of cells through the cell cycle, and the repair of sublethal, potentially lethal and potentially neoplastic transforming damage in γ-irradiated HeLa x skin fibroblast human hybrid cells has been examined. Cell growth and cell cycle progression were essentially stopped at this reduced temperature. Cell survival was dramatically reduced by holding confluent cultures for 6 h at 22 degrees C, as opposed to 37 degrees C, after 7.5 Gy γ radiation delivered at a rate of 2 Gy/min. Return of the cells to 37 degrees C for 6 h after holding at 22 degrees C did not result in increased survival. A similar effect was obtained when the cells were held at 22 degrees C between split-dose irradiation of log-phase cultures where no increase in survival was observed over a split-dose interval of 4 h. In this case a partial increase in survival was observed upon returning the cells to 37 degrees C for 3 h after holding at 22 degrees C for the first 3 h of the split-dose interval. Neoplastic transformation frequency was not enhanced by holding confluent cultures for 6 h at 22 degrees C after 7.5 Gy γ radiation. This is consistent with previous observations that misrepair of potentially neoplastic transforming damage already occurs at 37 degrees C. The overall results are interpreted in terms of the reduced temperature favoring misrepair, rather than inhibition of repair, of sublethal, potentially lethal and potentially transforming radiation damage. 24 refs., 5 figs., 3 tabs

  14. Tensile strength of structural concrete repaired with hi-bond polymer modified mortar

    International Nuclear Information System (INIS)

    Khaskheli, G.B.

    2009-01-01

    Repair of cracks in concrete is often required to save the concrete structures. Appearance of crack in concrete is bound with the tensile strength of concrete. Recently a cement factory in Sindh has launched a HBPMM (Hi-Bond Polymer Modified Mortar) that can be used as a concrete repairing material instead of normal OPC (Ordinary Portland Cement). It is needed to investigate its performance compared to that of OPC. In total 144 concrete cylinders (150x300mm) having strength of 3000 and 5000 psi were manufactured. These cylinders were then splitted by using a UTM (Universal Testing Machine) and their actual tensile strength was obtained. The concrete cylinders were then repaired with different applications of HBPMM and arc. The repaired samples were again splitted at different curing ages (3, 7 and 28 days) and their tensile strength after repair was obtained. The results show that the concrete cylinders repaired with HBPMM could give better tensile strength than that repaired with arc, the tensile strength of concrete cylinders after repair could increase with increase in the application of repairing material i.e. HBPMM or OPC and with curing time, and HBPMM could remain more effective in case of rich mix concrete than that of normal mix concrete. (author)

  15. Standard Model Particles from Split Octonions

    Directory of Open Access Journals (Sweden)

    Gogberashvili M.

    2016-01-01

    Full Text Available We model physical signals using elements of the algebra of split octonions over the field of real numbers. Elementary particles are corresponded to the special elements of the algebra that nullify octonionic norms (zero divisors. It is shown that the standard model particle spectrum naturally follows from the classification of the independent primitive zero divisors of split octonions.

  16. Cheating More when the Spoils Are Split

    Science.gov (United States)

    Wiltermuth, Scott S.

    2011-01-01

    Four experiments demonstrated that people are more likely to cheat when the benefits of doing so are split with another person, even an anonymous stranger, than when the actor alone captures all of the benefits. In three of the studies, splitting the benefits of over-reporting one's performance on a task made such over-reporting seem less…

  17. Split Scheduling with Uniform Setup Times

    NARCIS (Netherlands)

    Schalekamp, F.; Sitters, R.A.; van der Ster, S.L.; Stougie, L.; Verdugo, V.; van Zuylen, A.

    2015-01-01

    We study a scheduling problem in which jobs may be split into parts, where the parts of a split job may be processed simultaneously on more than one machine. Each part of a job requires a setup time, however, on the machine where the job part is processed. During setup, a machine cannot process or

  18. Split scheduling with uniform setup times.

    NARCIS (Netherlands)

    F. Schalekamp; R.A. Sitters (René); S.L. van der Ster; L. Stougie (Leen); V. Verdugo; A. van Zuylen

    2015-01-01

    htmlabstractWe study a scheduling problem in which jobs may be split into parts, where the parts of a split job may be processed simultaneously on more than one machine. Each part of a job requires a setup time, however, on the machine where the job part is processed. During setup, a

  19. Cortical splitting of the mandible after irradiation. Special reference to osteoradionecrosis

    International Nuclear Information System (INIS)

    Katsura, Kouji; Ito, Jusuke; Hayashi, Takafumi; Taira, Shuhzou; Nakajima, Syunichi

    2001-01-01

    The purpose of this study was to discuss the relationship between radiation bone injuries and a splitting of the cortical bone in the radiation field. Between January 1993 and September 1998, 53 patients with head and neck cancer received radiotherapy. The study cohort consisted of 23 patients who were followed with computed tomographic scans more than one year after radiotherapy. We evaluated clinical and computed tomographic features. Computed tomographic scanning was performed with a section thickness of 3 or 4 mm. Bone images were obtained with identical window width (4000 Haunsfield units) and window level (1000 Haunsfield units). Splitting of the cortical bone was defined as disappearance of bone density in the cortical bone, showing a linear shape running parallel to the surface of the cortex. Splitting appeared in 9 sites in 8 patients. All patients fulfilled UICC criteria for classifying oral cancer. Most of the patients received external irradiation with a total radiation dose of 50 or 60 Gy. In all cases, splitting was found in the mandibular cortex at the site of muscle attachment, that was included in the radiation field. Appearance of bone changes in chronological order were periosteal reaction, splitting and bone necrosis. We speculate that splitting results from injuries to bone structure cells caused by blood flow disturbance after surgery and radiotherapy. It is suggested that such splitting can be a predictor of osteoradionecrosis. (author)

  20. Particulate photocatalysts for overall water splitting

    Science.gov (United States)

    Chen, Shanshan; Takata, Tsuyoshi; Domen, Kazunari

    2017-10-01

    The conversion of solar energy to chemical energy is a promising way of generating renewable energy. Hydrogen production by means of water splitting over semiconductor photocatalysts is a simple, cost-effective approach to large-scale solar hydrogen synthesis. Since the discovery of the Honda-Fujishima effect, considerable progress has been made in this field, and numerous photocatalytic materials and water-splitting systems have been developed. In this Review, we summarize existing water-splitting systems based on particulate photocatalysts, focusing on the main components: light-harvesting semiconductors and co-catalysts. The essential design principles of the materials employed for overall water-splitting systems based on one-step and two-step photoexcitation are also discussed, concentrating on three elementary processes: photoabsorption, charge transfer and surface catalytic reactions. Finally, we outline challenges and potential advances associated with solar water splitting by particulate photocatalysts for future commercial applications.

  1. Accuracy of tablet splitting and liquid measurements: an examination of who, what and how.

    Science.gov (United States)

    Abu-Geras, Dana; Hadziomerovic, Dunja; Leau, Andrew; Khan, Ramzan Nazim; Gudka, Sajni; Locher, Cornelia; Razaghikashani, Maryam; Lim, Lee Yong

    2017-05-01

    To examine factors that might affect the ability of patients to accurately halve tablets or measure a 5-ml liquid dose. Eighty-eight participants split four different placebo tablets by hand and using a tablet splitter, while 85 participants measured 5 ml of water, 0.5% methylcellulose (MC) and 1% MC using a syringe and dosing cup. Accuracy of manipulation was determined by mass measurements. The general population was less able than pharmacy students to break tablets into equal parts, although age, gender and prior experience were insignificant factors. Greater accuracy of tablet halving was observed with tablet splitter, with scored tablets split more equally than unscored tablets. Tablet size did not affect the accuracy of splitting. However, >25% of small scored tablets failed to be split by hand, and 41% of large unscored tablets were split into >2 portions in the tablet splitter. In liquid measurement, the syringe provided more accurate volume measurements than the dosing cup, with higher accuracy observed for the more viscous MC solutions than water. Formulation characteristics and manipulation technique have greater influences on the accuracy of medication modification and should be considered in off-label drug use in vulnerable populations. © 2016 Royal Pharmaceutical Society.

  2. DNA Repair Defects and Chromosomal Aberrations

    Science.gov (United States)

    Hada, Megumi; George, K. A.; Huff, J. L.; Pluth, J. M.; Cucinotta, F. A.

    2009-01-01

    Yields of chromosome aberrations were assessed in cells deficient in DNA doublestrand break (DSB) repair, after exposure to acute or to low-dose-rate (0.018 Gy/hr) gamma rays or acute high LET iron nuclei. We studied several cell lines including fibroblasts deficient in ATM (ataxia telangiectasia mutated; product of the gene that is mutated in ataxia telangiectasia patients) or NBS (nibrin; product of the gene mutated in the Nijmegen breakage syndrome), and gliomablastoma cells that are proficient or lacking in DNA-dependent protein kinase (DNA-PK) activity. Chromosomes were analyzed using the fluorescence in situ hybridization (FISH) chromosome painting method in cells at the first division post irradiation, and chromosome aberrations were identified as either simple exchanges (translocations and dicentrics) or complex exchanges (involving >2 breaks in 2 or more chromosomes). Gamma irradiation induced greater yields of both simple and complex exchanges in the DSB repair-defective cells than in the normal cells. The quadratic dose-response terms for both simple and complex chromosome exchanges were significantly higher for the ATM- and NBS-deficient lines than for normal fibroblasts. However, in the NBS cells the linear dose-response term was significantly higher only for simple exchanges. The large increases in the quadratic dose-response terms in these repair-defective cell lines points the importance of the functions of ATM and NBS in chromatin modifications to facilitate correct DSB repair and minimize the formation of aberrations. The differences found between ATM- and NBS-deficient cells at low doses suggest that important questions should with regard to applying observations of radiation sensitivity at high dose to low-dose exposures. For aberrations induced by iron nuclei, regression models preferred purely linear dose responses for simple exchanges and quadratic dose responses for complex exchanges. Relative biological effectiveness (RBE) factors of all of

  3. Repair during multifraction exposures: spheroids versus monolayers

    International Nuclear Information System (INIS)

    Durand, R.E.

    1984-01-01

    Many type of mammalian cells, when grown in culture as multicell spheroids, display an increased ability to accumulate and repair sublethal radiation damage which has been called the ''contact effect''. Since this effect has the potential to markedly modify the multifraction radiation response of cells in V79 spheroids relative to cells in monolayer cultures, an investigation was made of regimens ranging from 1 to 100 fractions. Effective dose rates were chosen near 1 Gy h -1 to inhibit cell progression and thus simplify analysis of the results. As expected, larger doses per fraction produced more net cell killing in both systems than lower doses per fraction. Additionally, less killing of spheroid cells was observed in all regimens, in accord with their greater potential for repair. However, when the data were expressed as isoeffect curves, the spheroid and monolayer curves converged as the number of fractions increased. Thus, quite similar inherent sensitivity and repair capabilities would be predicted for ultra-low doses per fraction. High precision techniques for defining survival after doses of radiation from 0.2 to 1 Gy were, however, still able to demonstrate a survival advantage for cells grown as spheroids. (author)

  4. TH-E-BRF-01: Exploiting Tumor Shrinkage in Split-Course Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Unkelbach, J; Craft, D; Hong, T; Papp, D; Wolfgang, J; Bortfeld, T [Massachusetts General Hospital, Boston, MA (United States); Ramakrishnan, J [University of Wisconsin, Madison, Wisconsin (United States); Salari, E [Wichita State University, Wichita, KS (United States)

    2014-06-15

    Purpose: In split-course radiotherapy, a patient is treated in several stages separated by weeks or months. This regimen has been motivated by radiobiological considerations. However, using modern image-guidance, it also provides an approach to reduce normal tissue dose by exploiting tumor shrinkage. In this work, we consider the optimal design of split-course treatments, motivated by the clinical management of large liver tumors for which normal liver dose constraints prohibit the administration of an ablative radiation dose in a single treatment. Methods: We introduce a dynamic tumor model that incorporates three factors: radiation induced cell kill, tumor shrinkage, and tumor cell repopulation. The design of splitcourse radiotherapy is formulated as a mathematical optimization problem in which the total dose to the liver is minimized, subject to delivering the prescribed dose to the tumor. Based on the model, we gain insight into the optimal administration of radiation over time, i.e. the optimal treatment gaps and dose levels. Results: We analyze treatments consisting of two stages in detail. The analysis confirms the intuition that the second stage should be delivered just before the tumor size reaches a minimum and repopulation overcompensates shrinking. Furthermore, it was found that, for a large range of model parameters, approximately one third of the dose should be delivered in the first stage. The projected benefit of split-course treatments in terms of liver sparing depends on model assumptions. However, the model predicts large liver dose reductions by more than a factor of two for plausible model parameters. Conclusion: The analysis of the tumor model suggests that substantial reduction in normal tissue dose can be achieved by exploiting tumor shrinkage via an optimal design of multi-stage treatments. This suggests taking a fresh look at split-course radiotherapy for selected disease sites where substantial tumor regression translates into reduced

  5. TH-E-BRF-01: Exploiting Tumor Shrinkage in Split-Course Radiotherapy

    International Nuclear Information System (INIS)

    Unkelbach, J; Craft, D; Hong, T; Papp, D; Wolfgang, J; Bortfeld, T; Ramakrishnan, J; Salari, E

    2014-01-01

    Purpose: In split-course radiotherapy, a patient is treated in several stages separated by weeks or months. This regimen has been motivated by radiobiological considerations. However, using modern image-guidance, it also provides an approach to reduce normal tissue dose by exploiting tumor shrinkage. In this work, we consider the optimal design of split-course treatments, motivated by the clinical management of large liver tumors for which normal liver dose constraints prohibit the administration of an ablative radiation dose in a single treatment. Methods: We introduce a dynamic tumor model that incorporates three factors: radiation induced cell kill, tumor shrinkage, and tumor cell repopulation. The design of splitcourse radiotherapy is formulated as a mathematical optimization problem in which the total dose to the liver is minimized, subject to delivering the prescribed dose to the tumor. Based on the model, we gain insight into the optimal administration of radiation over time, i.e. the optimal treatment gaps and dose levels. Results: We analyze treatments consisting of two stages in detail. The analysis confirms the intuition that the second stage should be delivered just before the tumor size reaches a minimum and repopulation overcompensates shrinking. Furthermore, it was found that, for a large range of model parameters, approximately one third of the dose should be delivered in the first stage. The projected benefit of split-course treatments in terms of liver sparing depends on model assumptions. However, the model predicts large liver dose reductions by more than a factor of two for plausible model parameters. Conclusion: The analysis of the tumor model suggests that substantial reduction in normal tissue dose can be achieved by exploiting tumor shrinkage via an optimal design of multi-stage treatments. This suggests taking a fresh look at split-course radiotherapy for selected disease sites where substantial tumor regression translates into reduced

  6. Impact of a warning CPOE system on the inappropriate pill splitting of prescribed medications in outpatients.

    Directory of Open Access Journals (Sweden)

    Chia-Chen Hsu

    Full Text Available Prescribing inappropriate pill splitting is not rare in clinical practice. To reduce inappropriate pill splitting, we developed an automatic warning system linked to a computerized physician order entry (CPOE system for special oral formulation drugs in outpatient settings. We examined the impact of the warning system on inappropriate prescribing of pill splitting and assess prescribers' responses to the warnings.Drugs with extended-release or enteric-coated formulations that were not originally intended to be split were recognized as "special oral formulations". A hard-stop system which could examine non-integer doses of drugs with special oral formulations, provide warnings to interrupt inappropriate prescriptions was integrated in CPOE in a medical center since June 2010. We designed an intervention study to compare the inappropriate splitting before and after the implementation of the warning system (baseline period 2010 January to May vs. intervention period 2010 June to 2011 August. During the intervention period, prescription changes in response to a warning were logged and analyzed.A total of 470,611 prescribed drug items with 34 different drugs with special oral formulations were prescribed in the study period. During the 15-month intervention period, 909 warnings for 26 different drugs were triggered among 354,523 prescribed drug items with special oral formulations. The warning rate of inappropriate splitting in the late intervention period was lower than those in baseline period (0.16% vs. 0.61%, incidence rate ratio 0.27, 95% CI 0.23-0.31, P<0.001. In respond to warnings, physicians had to make adjustments, of which the majority was changing to an unsplit pill (72.9%.The interruptive warning system could avoid the prescriptions with inappropriate pill splitting. Accordingly, physicians changed their behavior of prescribing special oral formulations regarding inappropriate pill splitting. We suggest the establishment of such system

  7. Split-coil-system SULTAN

    International Nuclear Information System (INIS)

    Vecsey, G.

    1992-08-01

    The high field superconductor test facility SULTAN started operation successfully in May 1992. Originally designed for testing full scale conductors for the large magnets of the next generation fusion reactors, the SULTAN facility installed at PSI (Switzerland) was designed as a common venture of three European Laboratories: ENEA (Italy), ECN (Netherlands) and PSI, and built by ENEA and PSI in the framework of the Euratom Fusion Technology Program. Presently the largest facility in the world, with its superconducting split coil system generating 11 Tesla in a 0.6 m bore, it is ready now for testing superconductor samples with currents up to 50 kA at variable cooling conditions. Similar tests can be arranged also for other applications. SULTAN is offered by the European Community as a contribution to the worldwide cooperation for the next step of fusion reactor development ITER. First measurements on conductor developed by CEA (Cadarache) are now in progress. Others like those of ENEA and CERN will follow. For 1993, a test of an Italian 12 TZ model coil for fusion application is planned. SULTAN is a worldwide unique facility marking the competitive presence of Swiss technology in the field of applied superconductivity research. Based on development and design of PSI, the high field Nb 3 Sn superconductors and coils were fabricated at the works of Kabelwerke Brugg and ABB, numerous Swiss companies contributed to the success of this international effort. Financing of the Swiss contribution of SULTAN was made available by NEFF, BEW, BBW, PSI and EURATOM. (author) figs., tabs., 20 refs

  8. Communication: Tunnelling splitting in the phosphine molecule

    Science.gov (United States)

    Sousa-Silva, Clara; Tennyson, Jonathan; Yurchenko, Sergey N.

    2016-09-01

    Splitting due to tunnelling via the potential energy barrier has played a significant role in the study of molecular spectra since the early days of spectroscopy. The observation of the ammonia doublet led to attempts to find a phosphine analogous, but these have so far failed due to its considerably higher barrier. Full dimensional, variational nuclear motion calculations are used to predict splittings as a function of excitation energy. Simulated spectra suggest that such splittings should be observable in the near infrared via overtones of the ν2 bending mode starting with 4ν2.

  9. Communication: Tunnelling splitting in the phosphine molecule

    Energy Technology Data Exchange (ETDEWEB)

    Sousa-Silva, Clara; Tennyson, Jonathan; Yurchenko, Sergey N. [Department of Physics and Astronomy, University College London, London WC1E 6BT (United Kingdom)

    2016-09-07

    Splitting due to tunnelling via the potential energy barrier has played a significant role in the study of molecular spectra since the early days of spectroscopy. The observation of the ammonia doublet led to attempts to find a phosphine analogous, but these have so far failed due to its considerably higher barrier. Full dimensional, variational nuclear motion calculations are used to predict splittings as a function of excitation energy. Simulated spectra suggest that such splittings should be observable in the near infrared via overtones of the ν{sub 2} bending mode starting with 4ν{sub 2}.

  10. Tensor products of higher almost split sequences

    OpenAIRE

    Pasquali, Andrea

    2015-01-01

    We investigate how the higher almost split sequences over a tensor product of algebras are related to those over each factor. Herschend and Iyama gave a precise criterion for when the tensor product of an $n$-representation finite algebra and an $m$-representation finite algebra is $(n+m)$-representation finite. In this case we give a complete description of the higher almost split sequences over the tensor product by expressing every higher almost split sequence as the mapping cone of a suit...

  11. Semi-strong split domination in graphs

    Directory of Open Access Journals (Sweden)

    Anwar Alwardi

    2014-06-01

    Full Text Available Given a graph $G = (V,E$, a dominating set $D subseteq V$ is called a semi-strong split dominating set of $G$ if $|V setminus D| geq 1$ and the maximum degree of the subgraph induced by $V setminus D$ is 1. The minimum cardinality of a semi-strong split dominating set (SSSDS of G is the semi-strong split domination number of G, denoted $gamma_{sss}(G$. In this work, we introduce the concept and prove several results regarding it.

  12. Splitting Functions at High Transverse Momentum

    CERN Document Server

    Moutafis, Rhea Penelope; CERN. Geneva. TH Department

    2017-01-01

    Among the production channels of the Higgs boson one contribution could become significant at high transverse momentum which is the radiation of a Higgs boson from another particle. This note focuses on the calculation of splitting functions and cross sections of such processes. The calculation is first carried out on the example $e\\rightarrow e\\gamma$ to illustrate the way splitting functions are calculated. Then the splitting function of $e\\rightarrow eh$ is calculated in similar fashion. This procedure can easily be generalized to processes such as $q\\rightarrow qh$ or $g\\rightarrow gh$.

  13. Repair of ultraviolet light damage to the DNA of cultured human epidermal keratinocytes and fibroblasts

    International Nuclear Information System (INIS)

    Taichman, L.B.; Setlow, R.B.

    1979-01-01

    Pure cultures of dermal fibroblasts and epidermal keroatinocytes have been obtained from a single biopsy of newborn foreskin. The cells were labeled, exposed to several doses of uv light, and allowed to repair in the dark for 16 h. The number of pyrimidine dimers before and after repair was assessed by measuring the numbers of sites in the DNA sensitive to a specific uv endonuclease. At all doses used, the extent of repair was similar in the cultured keratinocytes and cultured fibroblasts

  14. Inhibition of DNA-double strand break repair by antimony compounds

    International Nuclear Information System (INIS)

    Takahashi, Sentaro; Sato, Hiroshi; Kubota, Yoshihisa; Utsumi, Hiroshi; Bedford, Joel S.; Okayasu, Ryuichi

    2002-01-01

    DNA double strand breaks (DSBs), induced by γ-irradiation in Chinese hamster ovary cells, were used to examine whether antimony compounds affect the repair of DNA damage. The cells were first incubated with antimony trichloride or antimony potassium tartrate (both Sb(III)) for 2 h, and then irradiated with γ-rays at a dose of 40 Gy. The DNA DSB was quantified with pulsed field gel electrophoresis immediately after irradiation (non-repair group) as well as at 30 min post-irradiation (repair group). The degree of repair inhibition was determined by the differences in the amount of DNA DSB between non-repair and repair groups. Both antimony compounds inhibited repair of DNA DSB in a dose dependent manner. In trichloride, 0.2 mM antimony significantly inhibited the rejoining of DSB, while 0.4 mM was necessary in potassium antimony tartrate. The mean lethal doses, D 0 , for the treatment with antimony trichloride and antimony potassium tartrate, were approximately 0.21 and 0.12 mM, respectively. This indicates that the repair inhibition by antimony trichloride occurred in the dose range near D 0 , but the antimony potassium tartrate inhibited the repair at doses where most cells lost their proliferating ability. This is the first report to indicate that antimony compounds may inhibit the repair of radiation-induced DNA DSB

  15. Split-Volume Treatment Planning of Multiple Consecutive Vertebral Body Metastases for Cyberknife Image-Guided Robotic Radiosurgery

    International Nuclear Information System (INIS)

    Sahgal, Arjun; Chuang, Cynthia; Larson, David; Huang, Kim; Petti, Paula; Weinstein, Phil; Ma Lijun

    2008-01-01

    Cyberknife treatment planning of multiple consecutive vertebral body metastases is challenging due to large target volumes adjacent to critical normal tissues. A split-volume treatment planning technique was developed to improve the treatment plan quality of such lesions. Treatment plans were generated for 1 to 5 consecutive thoracic vertebral bodies (CVBM) prescribing a total dose of 24 Gy in 3 fractions. The planning target volume (PTV) consisted of the entire vertebral body(ies). Treatment plans were generated considering both the de novo clinical scenario (no prior radiation), imposing a dose limit of 8 Gy to 1 cc of spinal cord, and the retreatment scenario (prior radiation) with a dose limit of 3 Gy to 1 cc of spinal cord. The split-volume planning technique was compared with the standard full-volume technique only for targets ranging from 2 to 5 CVBM in length. The primary endpoint was to obtain best PTV coverage by the 24 Gy prescription isodose line. A total of 18 treatment plans were generated (10 standard and 8 split-volume). PTV coverage by the 24-Gy isodose line worsened consistently as the number of CVBM increased for both the de novo and retreatment scenario. Split-volume planning was achieved by introducing a 0.5-cm gap, splitting the standard full-volume PTV into 2 equal length PTVs. In every case, split-volume planning resulted in improved PTV coverage by the 24-Gy isodose line ranging from 4% to 12% for the de novo scenario and, 8% to 17% for the retreatment scenario. We did not observe a significant trend for increased monitor units required, or higher doses to spinal cord or esophagus, with split-volume planning. Split-volume treatment planning significantly improves Cyberknife treatment plan quality for CVBM, as compared to the standard technique. This technique may be of particular importance in clinical situations where stringent spinal cord dose limits are required

  16. Yield and nutritional efficiency of corn in response to rates and splits of nitrogen fertilization

    OpenAIRE

    Amado, Telmo Jorge Carneiro; Villalba, Enrique Oswin Hahn; Bortolotto, Rafael Pivotto; Nora, Douglas Dalla; Bragagnolo, Jardes; León, Enrique Asterio Benítez

    2017-01-01

    ABSTRACT Despite its relevance, nitrogen is poorly utilized by the plants when improperly applied. Thus, the objective of this study was to evaluate the yield and nitrogen use efficiency (NUE) in corn in response to doses and split application of nitrogen fertilization. The experimental design was a randomized block design, with three replications. Doses of nitrogen of 0, 30, 60 and 180 kg ha-1 were applied at sowing in order to create different nutritional status of corn plants and to obtain...

  17. Splitting Strip Detector Clusters in Dense Environments

    CERN Document Server

    Nachman, Benjamin Philip; The ATLAS collaboration

    2018-01-01

    Tracking in high density environments, particularly in high energy jets, plays an important role in many physics analyses at the LHC. In such environments, there is significant degradation of track reconstruction performance. Between runs 1 and 2, ATLAS implemented an algorithm that splits pixel clusters originating from multiple charged particles, using charge information, resulting in the recovery of much of the lost efficiency. However, no attempt was made in prior work to split merged clusters in the Semi Conductor Tracker (SCT), which does not measure charge information. In spite of the lack of charge information in SCT, a cluster-splitting algorithm has been developed in this work. It is based primarily on the difference between the observed cluster width and the expected cluster width, which is derived from track incidence angle. The performance of this algorithm is found to be competitive with the existing pixel cluster splitting based on track information.

  18. Baryons electromagnetic mass splittings in potential models

    International Nuclear Information System (INIS)

    Genovese, M.; Richard, J.-M.; Silvestre-Brac, B.; Varga, K.

    1998-01-01

    We study electromagnetic mass splittings of charmed baryons. We point out discrepancies among theoretical predictions in non-relativistic potential models; none of these predictions seems supported by experimental data. A new calculation is presented

  19. Snowmobile Repair. Teacher Edition.

    Science.gov (United States)

    Hennessy, Stephen S.; Conrad, Rex

    This teacher's guide contains 14 units on snowmobile repair: (1) introduction to snowmobile repair; (2) skis, front suspension, and steering; (3) drive clutch; (4) drive belts; (5) driven clutch; (6) chain drives; (7) jackshafts and axles; (8) rear suspension; (9) tracks; (10) shock absorbers; (11) brakes; (12) engines; (13) ignition and…

  20. DNA repair genes

    International Nuclear Information System (INIS)

    Morimyo, Mitsuoki

    1995-01-01

    Fission yeast S. pombe is assumed to be a good model for cloning of human DNA repair genes, because human gene is normally expressed in S. pombe and has a very similar protein sequence to yeast protein. We have tried to elucidate the DNA repair mechanisms of S. pombe as a model system for those of mammals. (J.P.N.)

  1. Split School of High Energy Physics 2015

    CERN Document Server

    2015-01-01

    Split School of High Energy Physics 2015 (SSHEP 2015) was held at the Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture (FESB), University of Split, from September 14 to September 18, 2015. SSHEP 2015 aimed at master and PhD students who were interested in topics pertaining to High Energy Physics. SSHEP 2015 is the sixth edition of the High Energy Physics School. Previous five editions were held at the Department of Physics, University of Sarajevo, Bosnia and Herzegovina.

  2. Split-plot designs for multistage experimentation

    DEFF Research Database (Denmark)

    Kulahci, Murat; Tyssedal, John

    2016-01-01

    at the same time will be more efficient. However, there have been only a few attempts in the literature to provide an adequate and easy-to-use approach for this problem. In this paper, we present a novel methodology for constructing two-level split-plot and multistage experiments. The methodology is based...... be accommodated in each stage. Furthermore, split-plot designs for multistage experiments with good projective properties are also provided....

  3. Splitting automorphisms of free Burnside groups

    International Nuclear Information System (INIS)

    Atabekyan, Varuzhan S

    2013-01-01

    It is proved that, if the order of a splitting automorphism of odd period n≥1003 of a free Burnside group B(m,n) is a prime, then the automorphism is inner. This implies, for every prime n≥1009, an affirmative answer to the question on the coincidence of the splitting automorphisms of period n of the group B(m,n) with the inner automorphisms (this question was posed in the 'Kourovka Notebook' in 1990). Bibliography: 17 titles.

  4. Are Ducted Mini-Splits Worth It?

    Energy Technology Data Exchange (ETDEWEB)

    Winkler, Jonathan M [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Maguire, Jeffrey B [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Metzger, Cheryn E. [Pacific Northwest National Laboratory; Zhang, Jason [Pacific Northwest National Laboratory

    2018-02-01

    Ducted mini-split heat pumps are gaining popularity in some regions of the country due to their energy-efficient specifications and their ability to be hidden from sight. Although product and install costs are typically higher than the ductless mini-split heat pumps, this technology is well worth the premium for some homeowners who do not like to see an indoor unit in their living area. Due to the interest in this technology by local utilities and homeowners, the Bonneville Power Administration (BPA) has funded the Pacific Northwest National Laboratory (PNNL) and the National Renewable Energy Laboratory (NREL) to develop capabilities within the Building Energy Optimization (BEopt) tool to model ducted mini-split heat pumps. After the fundamental capabilities were added, energy-use results could be compared to other technologies that were already in BEopt, such as zonal electric resistance heat, central air source heat pumps, and ductless mini-split heat pumps. Each of these technologies was then compared using five prototype configurations in three different BPA heating zones to determine how the ducted mini-split technology would perform under different scenarios. The result of this project was a set of EnergyPlus models representing the various prototype configurations in each climate zone. Overall, the ducted mini-split heat pumps saved about 33-60% compared to zonal electric resistance heat (with window AC systems modeled in the summer). The results also showed that the ducted mini-split systems used about 4% more energy than the ductless mini-split systems, which saved about 37-64% compared to electric zonal heat (depending on the prototype and climate).

  5. Mort Rainey's Split Personality in Secret Window

    OpenAIRE

    Sandjaya, Cynthya; Limanta, Liem Satya

    2013-01-01

    Psychological issue is the main issue discussed in David Koepp's Secret Window through its main character, Mort Rainey. Rainey's psychological struggle will be the main theme in this research. This thesis examines Rainey's split personality. Furthermore, in this study, we want to analyze the process of how Mort Rainey's personality splits into two different personalities. To meet the answer of this study, we will use the theory of Dissociative Identity Disorder with a support from Sigmund Fre...

  6. Polarization Insensitivity in Double-Split Ring and Triple-Split Ring Terahertz Resonators

    International Nuclear Information System (INIS)

    Wu Qian-Nan; Lan Feng; Tang Xiao-Pin; Yang Zi-Qiang

    2015-01-01

    A modified double-split ring resonator and a modified triple-split ring resonator, which offer polarization-insensitive performance, are investigated, designed and fabricated. By displacing the two gaps of the conventional double-split ring resonator away from the center, the second resonant frequency for the 0° polarized wave and the resonant frequency for the 90° polarized wave become increasingly close to each other until they are finally identical. Theoretical and experimental results show that the modified double-split ring resonator and the modified triple-split ring resonator are insensitive to different polarized waves and show strong resonant frequency dips near 433 and 444 GHz, respectively. The results of this work suggest new opportunities for the investigation and design of polarization-dependent terahertz devices based on split ring resonators. (paper)

  7. DNA repair protocols

    DEFF Research Database (Denmark)

    Bjergbæk, Lotte

    In its 3rd edition, this Methods in Molecular Biology(TM) book covers the eukaryotic response to genomic insult including advanced protocols and standard techniques in the field of DNA repair. Offers expert guidance for DNA repair, recombination, and replication. Current knowledge of the mechanisms...... that regulate DNA repair has grown significantly over the past years with technology advances such as RNA interference, advanced proteomics and microscopy as well as high throughput screens. The third edition of DNA Repair Protocols covers various aspects of the eukaryotic response to genomic insult including...... recent advanced protocols as well as standard techniques used in the field of DNA repair. Both mammalian and non-mammalian model organisms are covered in the book, and many of the techniques can be applied with only minor modifications to other systems than the one described. Written in the highly...

  8. Oligodendroglial response to ionizing radiation: Dose and dose-rate response

    International Nuclear Information System (INIS)

    Levy, R.P.

    1991-12-01

    An in vitro system using neuroglia from neonatal rat brain was developed to examine the morphologic, immunocytochemical and biochemical response of oligodendroglia to ionizing radiation. Following acute γ-irradiation at day-in-culture (DIC) 8, oligodendrocyte counts at DIC 14 were 55% to 65% of control values after 2 Gy, and 29% to 36% after 5 Gy. Counts increased to near-normal levels at DIC 21 in the 2 Gy group and to 75% of normal in the 5 Gy group. Myelin basic protein levels (MBP) at DIC 14 were 60% of control values after 2 Gy, and 40% after 5 Gy. At DIC 21, MBP after 2 Gy was 45% greater than that observed at DIC 14, but MBP, as a fraction of age-matched control values, dropped from 60% to 50%. Following 5 Gy, absolute MBP changed little between DIC 14 and DIC 21, but decreased from 40% to 25% of control cultures. The response to split-dose irradiation indicated that nearly all sublethal damage in the oligodendrocyte population (and its precursors) was repaired within 3 h to 4 h. A new compartmental cell model for radiation response in vitro of the oligodendrocyte population is proposed and examined in relation to the potential reaction to radiation injury in the brain

  9. Oligodendroglial response to ionizing radiation: Dose and dose-rate response

    Energy Technology Data Exchange (ETDEWEB)

    Levy, Richard P. [Univ. of California, Berkeley, CA (United States)

    1991-12-01

    An in vitro system using neuroglia from neonatal rat brain was developed to examine the morphologic, immunocytochemical and biochemical response of oligodendroglia to ionizing radiation. Following acute γ-irradiation at day-in-culture (DIC) 8, oligodendrocyte counts at DIC 14 were 55% to 65% of control values after 2 Gy, and 29% to 36% after 5 Gy. Counts increased to near-normal levels at DIC 21 in the 2 Gy group and to 75% of normal in the 5 Gy group. Myelin basic protein levels (MBP) at DIC 14 were 60% of control values after 2 Gy, and 40% after 5 Gy. At DIC 21, MBP after 2 Gy was 45% greater than that observed at DIC 14, but MBP, as a fraction of age-matched control values, dropped from 60% to 50%. Following 5 Gy, absolute MBP changed little between DIC 14 and DIC 21, but decreased from 40% to 25% of control cultures. The response to split-dose irradiation indicated that nearly all sublethal damage in the oligodendrocyte population (and its precursors) was repaired within 3 h to 4 h. A new compartmental cell model for radiation response in vitro of the oligodendrocyte population is proposed and examined in relation to the potential reaction to radiation injury in the brain.

  10. Oligodendroglial response to ionizing radiation: Dose and dose-rate response

    Energy Technology Data Exchange (ETDEWEB)

    Levy, R.P.

    1991-12-01

    An in vitro system using neuroglia from neonatal rat brain was developed to examine the morphologic, immunocytochemical and biochemical response of oligodendroglia to ionizing radiation. Following acute {gamma}-irradiation at day-in-culture (DIC) 8, oligodendrocyte counts at DIC 14 were 55% to 65% of control values after 2 Gy, and 29% to 36% after 5 Gy. Counts increased to near-normal levels at DIC 21 in the 2 Gy group and to 75% of normal in the 5 Gy group. Myelin basic protein levels (MBP) at DIC 14 were 60% of control values after 2 Gy, and 40% after 5 Gy. At DIC 21, MBP after 2 Gy was 45% greater than that observed at DIC 14, but MBP, as a fraction of age-matched control values, dropped from 60% to 50%. Following 5 Gy, absolute MBP changed little between DIC 14 and DIC 21, but decreased from 40% to 25% of control cultures. The response to split-dose irradiation indicated that nearly all sublethal damage in the oligodendrocyte population (and its precursors) was repaired within 3 h to 4 h. A new compartmental cell model for radiation response in vitro of the oligodendrocyte population is proposed and examined in relation to the potential reaction to radiation injury in the brain.

  11. Low radiation doses and antinuclear lobby

    International Nuclear Information System (INIS)

    Drobnik, J.

    1987-01-01

    The probability of mutations or diseases resulting from other than radiation causes is negatively dependent on radiation. Thus, for instance, the incidence of cancer, is demonstrably lower in areas with a higher radiation background. The hypothesis is expressed that there exist repair mechanisms for DNA damage which will repair the damage, and will give priority to those genes which are currently active. Survival and stochastic processes are not dependent on the overall repair of DNA but on the repair of critical function genes. New discoveries shed a different light on views of the linear dependence of radiation damage on the low level doses. (M.D.)

  12. Immunocosmeceuticals: An emerging trend in repairing human hair damage

    Directory of Open Access Journals (Sweden)

    Karthika Selvan

    2013-01-01

    Full Text Available Hair is one of the most important portions for beauty care and in recent years grooming and cosmetic treatment of hair has drastically risen. Substantially, it may deteriorate and weaken the hair by modification of keratin protein. This makes the hair dry, brittle and split vend occurs due to loss of hair strength and the damage further increases with cosmetic treatments. The various poor ingredients are being used for repairing which have extremely poor compatibility with hair. Now the hair care products can be introduced with an active ingredient comprising a yolk derived anti-hair antibody immunoglobin obtained from egg of chickens immunized with damaged hair as antigen. This immuno-cosmeceuticals can repair the hair damage and imparts flexibility and smoothness to the hair. These effects are not lost by the ordinary shampooing. This article focuses on the characteristic of human hair, its damaging processes and the effects of immuno-cosmeceuticals for repairing the hair damage.

  13. Effects of low doses; Effet des faibles doses

    Energy Technology Data Exchange (ETDEWEB)

    Le Guen, B. [Electricite de France (EDF-LAM-SCAST), 93 - Saint-Denis (France)

    2001-07-01

    Actually, even though it is comfortable for the risk management, the hypothesis of the dose-effect relationship linearity is not confirmed for any model. In particular, in the area of low dose rate delivered by low let emitters. this hypothesis is debated at the light of recent observations, notably these ones relative to the mechanisms leading to genetic instability and induction eventuality of DNA repair. The problem of strong let emitters is still to solve. (N.C.)

  14. Repair models of cell survival and corresponding computer program for survival curve fitting

    International Nuclear Information System (INIS)

    Shen Xun; Hu Yiwei

    1992-01-01

    Some basic concepts and formulations of two repair models of survival, the incomplete repair (IR) model and the lethal-potentially lethal (LPL) model, are introduced. An IBM-PC computer program for survival curve fitting with these models was developed and applied to fit the survivals of human melanoma cells HX118 irradiated at different dose rates. Comparison was made between the repair models and two non-repair models, the multitar get-single hit model and the linear-quadratic model, in the fitting and analysis of the survival-dose curves. It was shown that either IR model or LPL model can fit a set of survival curves of different dose rates with same parameters and provide information on the repair capacity of cells. These two mathematical models could be very useful in quantitative study on the radiosensitivity and repair capacity of cells

  15. Repair in Ehrlich ascites tumor cells

    International Nuclear Information System (INIS)

    Wanna-Nakamura, S.S.

    1981-01-01

    Unscheduled DNA synthesis (UDS), an indicator of excision repair, was induced in freshly drawn Ehrlich ascites tumor cells (EAT), using ionizing radiation, far ultraviolet light (254 nm) or near uv light (365 nm) in combination with 8-methoxypsoralen. UDS was scored by grain counts in autoradiographs following the incorporation of tritium-labelled thymidine. The amount of UDS after each of these agents was expressed in terms of two parameters, viz. numer of cells showing repair and the mean number of grains per nucleus. The influence of radiation dose and of the duration of radioactive thymidine incubation were also examined. To test for a possible relationship between low mitotic index and repair capability, EAT cells were incubated in buffered salt media to lower the mitotic index. Cells kept in a buffered salt solution for 7 h show a marked drop in mitotic index compared to those incubated in minimal medium containing 15% fetal calf serum (MEM + FCS). This drop in mitotic index was reversible for up to 5 h, if cells were returned to MEM + FCS. Cells incubated in MEM + FCS also showed a decrease in mitotic activity compared to freshly drawn cells. This reduced mitotic index is approximately constant for up to 24 h. With the drop in mitotic index, EAT cells also show a drop in repair compared to freshly drawn cells. The repair capability of cells incubated in buffer can be restored by returning cells to MEM + FCS

  16. Repairing fuel for reinsertion

    International Nuclear Information System (INIS)

    Krukshenk, A.

    1986-01-01

    Eqiupment for nuclear reactor fuel assembly repairing produced by Westinghouse and Brawn Bovery companies is described. Repair of failed fuel assemblies replacement of defect fuel elements gives a noticeable economical effect. Thus if the cost of a new fuel assembly is 450-500 thousand dollars, the replacement of one fuel element in it costs approximately 40-60 thousand dollars. In simple cases repairing includes either removal of failed fuel elements from a fuel assembly and its reinsertion with the rest of fuel elements into the reactor core (reactor refueling), or replacement of unfailed fuel elements from one fuel assembly to a new one (fuel assembly overhaul and reconditioning)

  17. Automatic feathering of split fields for step-and-shoot intensity modulated radiation therapy

    International Nuclear Information System (INIS)

    Dogan, Nesrin; Leybovich, Leonid B; Sethi, Anil; Emami, Bahman

    2003-01-01

    Due to leaf travel range limitations of the Varian Dynamic Multileaf Collimator (DMLC) system, an IMRT field width exceeding 14.5 cm is split into two or more adjacent abutting sub-fields. The abutting sub-fields are then delivered as separate treatment fields. The accuracy of the delivery is very sensitive to multileaf positioning accuracy. The uncertainties in leaf and carriage positions cause errors in the delivered dose (e.g., hot or cold spots) along the match line of abutting sub-fields. The dose errors are proportional to the penumbra slope at the edge of each sub-field. To alleviate this problem, we developed techniques that feather the split line of IMRT fields. Feathering of the split line was achieved by dividing IMRT fields into several sub-groups with different split line positions. A Varian 21EX accelerator with an 80-leaf DLMC was used for IMRT delivery. Cylindrical targets with varying widths (>14.5 cm) were created to study the split line positions. Seven coplanar 6 MV fields were selected for planning using the NOMOS-CORVUS TM system. The isocentre of the fields was positioned at the centre of the target volume. Verification was done in a 30 x 30 x 30 cm 3 polystyrene phantom using film dosimetry. We investigated two techniques to move the split line from its original position or cause feathering of them: (1) varying the isocentre position along the target width and (2) introduction of a 'pseudo target' outside of the patient (phantom). The position of the 'pseudo target' was determined by analysing the divergence of IMRT fields. For target widths of 14-28 cm, IMRT fields were automatically split into two sub-fields, and the split line was positioned along the centre of the target by CORVUS. Measured dose distributions demonstrated that the dose to the critical structure was 10% higher than planned when the split line crossed through the centre of the target. Both methods of modifying the split line positions resulted in maximum shifts of ∼1 cm

  18. The kinetics of repair in mouse lung after fractionated irradiation

    International Nuclear Information System (INIS)

    Travis, E.L.; Thames, H.D.; Watkins, T.L.; Kiss, I.

    1987-01-01

    The kinetics of repair of sublethal damage in mouse lung was studied after fractionated doses of 137 Cs γ-rays. A wide range of doses per fraction (1.7-12 Gy) was given with interfraction intervals ranging from 0.5 to 24 h. Data were analysed by a direct method of analysis using the incomplete repair model. The half-time of repair (Tsub(1/2)) was 0.76 h for the pneumonitis phase of damage (up to 8 months) and 0.65 h for the later phase of damage up to 12 months. Rate of repair was dependent on fraction size for both phases of lung damage and was faster after large dose fractions than after small fractions. Tsub(1/2) was 0.6 h (95% c.1. 0.53, 0.69) for doses per fraction greater than 5 Gy and 0.83 h (95% c.1. 0.76, 0.92) for doses per fraction of 2 Gy. Repair was nearly complete by 6 h at least for the pneumonitis phase of damage. If extrapolated to humans, these results imply that treatments with multiple fractions per day involving the lung will not be limited by the necessity for interfraction intervals much longer than 6 h. (author)

  19. Energy efficiency investments in the context of split incentives among French households

    International Nuclear Information System (INIS)

    Charlier, Dorothée

    2015-01-01

    The residential sector offers considerable potential for reducing energy use and greenhouse gas (GHG) emissions, particularly through energy-efficient renovations. The objective of this study is twofold. First, I aim to provide initial empirical evidence of the extent to which split incentives between landlords and tenants may lead to underinvestment. Second, I investigate the influence of tax credits and energy burdens on energy efficiency expenditures. Given the complexity of studying the decision to invest in energy-saving renovations, I use a bivariate Tobit model to compare decisions about energy-efficient works and repair works, even when the renovation expenditures seem quite similar. The analysis shows that tenants are doubly penalized: they have high energy expenditures due to energy-inefficient building characteristics, and because they are poorer than homeowners, they are unable to invest in energy-saving systems. The results also confirm that tax credits are ineffective in the split incentives context. In terms of public policy, the government should focus on low-income tenants, and mandatory measures such as minimum standards seem appropriate. Financial support from a third-party financer also might be a solution. - Highlights: • I provide empirical evidence of underinvestment due to split incentives. • I investigate the influence of tax credit and energy burden on EE expenditures. • Results show that tax credits are ineffective in a context of split incentives. • Mandatory measures such as minimum standards seem to be appropriate. • Financial support from a third party financer can be also a solution.

  20. Evaluating efficiency of split VMAT plan for prostate cancer radiotherapy involving pelvic lymph nodes

    Energy Technology Data Exchange (ETDEWEB)

    Mun, Jun Ki; Son, Sang Jun; Kim, Dae Ho; Seo, Seok Jin [Dept. of Radiation Oncology, Seoul National University Hospital, Seoul (Korea, Republic of)

    2015-12-15

    The purpose of this study is to evaluate the efficiency of Split VMAT planning(Contouring rectum divided into an upper and a lower for reduce rectum dose) compare to Conventional VMAT planning(Contouring whole rectum) for prostate cancer radiotherapy involving pelvic lymph nodes. A total of 9 cases were enrolled. Each case received radiotherapy with Split VMAT planning to the prostate involving pelvic lymph nodes. Treatment was delivered using TrueBeam STX(Varian Medical Systems, USA) and planned on Eclipse(Ver. 10.0.42, Varian, USA), PRO3(Progressive Resolution Optimizer 10.0.28), AAA(Anisotropic Analytic Algorithm Ver. 10.0.28). Lower rectum contour was defined as starting 1 cm superior and ending 1 cm inferior to the prostate PTV, upper rectum is a part, except lower rectum from the whole rectum. Split VMAT plan parameters consisted of 10 MV coplanar 360° arcs. Each arc had 30° and 30° collimator angle, respectively. An SIB(Simultaneous Integrated Boost) treatment prescription was employed delivering 50.4 Gy to pelvic lymph nodes and 63- 70 Gy to the prostate in 28 fractions. D{sub mean} of whole rectum on Split VMAT plan was applied for DVC(Dose Volume Constraint) of the whole rectum for Conventional VMAT plan. In addition, all parameters were set to be the same of existing treatment plans. To minimize the dose difference that shows up randomly on optimizing, all plans were optimized and calculated twice respectively using a 0.2 cm grid. All plans were normalized to the prostate PTV{sub 100%} = 90% or 95%. A comparison of D{sub mean} of whole rectum, upperr ectum, lower rectum, and bladder, V{sub 50%} of upper rectum, total MU and H.I.(Homogeneity Index) and C.I.(Conformity Index) of the PTV was used for technique evaluation. All Split VMAT plans were verified by gamma test with portal dosimetry using EPID. Using DVH analysis, a difference between the Conventional and the Split VMAT plans was demonstrated. The Split VMAT plan demonstrated better in the D

  1. A new incomplete-repair model based on a ''reciprocal-time'' pattern of sublethal damage repair

    International Nuclear Information System (INIS)

    Dale, R.G.; Fowler, J.F.

    1999-01-01

    A radiobiological model for closely spaced non-instantaneous radiation fractions is presented, based on the premise that the time process of sublethal damage (SLD) repair is 'reciprocal-time' (second order), rather than exponential (first order), in form. The initial clinical implications of such an incomplete-repair model are assessed. A previously derived linear-quadratic-based model was revised to take account of the possibility that SLD may repair with time such that the fraction of an element of initial damage remaining at time t is given as 1/(1+zt), where z is an appropriate rate constant; z is the reciprocal of the first half-time (τ) of repair. The general equation so derived for incomplete repair is applicable to all types of radiotherapy delivered at high, low and medium dose-rate in fractions delivered at regular time intervals. The model allows both the fraction duration and interfraction intervals to vary between zero and infinity. For any given value of z, reciprocal repair is associated with an apparent 'slowing-down' in the SLD repair rate as treatment proceeds. The instantaneous repair rates are not directly governed by total dose or dose per fraction, but are influenced by the treatment duration and individual fraction duration. Instantaneous repair rates of SLD appear to be slower towards the end of a continuous treatment, and are also slower following 'long' fractions than they are following 'short' fractions. The new model, with its single repair-rate parameter, is shown to be capable of providing a degree of quantitative explanation for some enigmas that have been encountered in clinical studies. A single-component reciprocal repair process provides an alternative explanation for the apparent existence of a range of repair rates in human tissues, and which have hitherto been explained by postulating the existence of a multi-exponential repair process. The build-up of SLD over extended treatments is greater than would be inferred using a

  2. Evaluation of Mandibular Anatomy Associated With Bad Splits in Sagittal Split Ramus Osteotomy of Mandible.

    Science.gov (United States)

    Wang, Tongyue; Han, Jeong Joon; Oh, Hee-Kyun; Park, Hong-Ju; Jung, Seunggon; Park, Yeong-Joon; Kook, Min-Suk

    2016-07-01

    This study aimed to identify risk factors associated with bad splits during sagittal split ramus osteotomy by using three-dimensional computed tomography. This study included 8 bad splits and 47 normal patients without bad splits. Mandibular anatomic parameters related to osteotomy line were measured. These included anteroposterior width of the ramus at level of lingula, distance between external oblique ridge and lingula, distance between sigmoid notch and inferior border of mandible, mandibular angle, distance between inferior outer surface of mandibular canal and inferior border of mandible under distal root of second molar (MCEM), buccolingual thickness of the ramus at level of lingula, and buccolingual thickness of the area just distal to first molar (BTM1) and second molar (BTM2). The incidence of bad splits in 625 sagittal split osteotomies was 1.28%. Compared with normal group, bad split group exhibited significantly thinner BTM2 and shorter sigmoid notch and inferior border of mandible (P bad splits. These anatomic data may help surgeons to choose the safest surgical techniques and best osteotomy sites.

  3. An algorithm for the split-feasibility problems with application to the split-equality problem.

    Science.gov (United States)

    Chuang, Chih-Sheng; Chen, Chi-Ming

    2017-01-01

    In this paper, we study the split-feasibility problem in Hilbert spaces by using the projected reflected gradient algorithm. As applications, we study the convex linear inverse problem and the split-equality problem in Hilbert spaces, and we give new algorithms for these problems. Finally, numerical results are given for our main results.

  4. Urban pattern: Layout design by hierarchical domain splitting

    KAUST Repository

    Yang, Yongliang; Wang, Jun; Vouga, Etienne; Wonka, Peter

    2013-01-01

    We present a framework for generating street networks and parcel layouts. Our goal is the generation of high-quality layouts that can be used for urban planning and virtual environments. We propose a solution based on hierarchical domain splitting using two splitting types: streamline-based splitting, which splits a region along one or multiple streamlines of a cross field, and template-based splitting, which warps pre-designed templates to a region and uses the interior geometry of the template as the splitting lines. We combine these two splitting approaches into a hierarchical framework, providing automatic and interactive tools to explore the design space.

  5. Urban pattern: Layout design by hierarchical domain splitting

    KAUST Repository

    Yang, Yongliang

    2013-11-06

    We present a framework for generating street networks and parcel layouts. Our goal is the generation of high-quality layouts that can be used for urban planning and virtual environments. We propose a solution based on hierarchical domain splitting using two splitting types: streamline-based splitting, which splits a region along one or multiple streamlines of a cross field, and template-based splitting, which warps pre-designed templates to a region and uses the interior geometry of the template as the splitting lines. We combine these two splitting approaches into a hierarchical framework, providing automatic and interactive tools to explore the design space.

  6. DNA Repair Systems

    Indian Academy of Sciences (India)

    DNA molecule which makes it ideal for storage and propagation of genetic information. ... of these errors are broadly referred to as DNA repair. DNA can ... changes occur in the human genome per day. ..... nails, frequent physical and mental.

  7. Brain aneurysm repair - discharge

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000123.htm Brain aneurysm repair - discharge To use the sharing features ... this page, please enable JavaScript. You had a brain aneurysm . An aneurysm is a weak area in ...

  8. Ventral hernia repair

    Science.gov (United States)

    ... incarcerated) in the hernia and become impossible to push back in. This is usually painful. The blood supply ... you are lying down or that you cannot push back in. Risks The risks of ventral hernia repair ...

  9. Omphalocele repair - slideshow

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/presentations/100033.htm Omphalocele repair - series—Normal anatomy To use the sharing ... Go to slide 4 out of 4 Overview Omphalocele is an abdominal wall defect at the base ...

  10. Celebrating DNA's Repair Crew.

    Science.gov (United States)

    Kunkel, Thomas A

    2015-12-03

    This year, the Nobel Prize in Chemistry has been awarded to Tomas Lindahl, Aziz Sancar, and Paul Modrich for their seminal studies of the mechanisms by which cells from bacteria to man repair DNA damage that is generated by normal cellular metabolism and stress from the environment. These studies beautifully illustrate the remarkable power of DNA repair to influence life from evolution through disease susceptibility. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Symmetric splitting of very light systems

    International Nuclear Information System (INIS)

    Grotowski, K.; Majka, Z.; Planeta, R.

    1985-01-01

    Fission reactions that produce fragments close to one half the mass of the composite system are traditionally observed in heavy nuclei. In light systems, symmetric splitting is rarely observed and poorly understood. It would be interesting to verify the existence of the symmetric splitting of compound nuclei with A 12 C + 40 Ca, 141 MeV 9 Be + 40 Ca and 153 MeV 6 Li + 40 Ca. The out-of-plane correlation of symmetric products was also measured for the reaction 186 MeV 12 C + 40 Ca. The coincidence measurements of the 12 C + 40 Ca system demonstrated that essentially all of the inclusive yield of symmetric products around 40 0 results from a binary decay. To characterize the dependence of the symmetric splitting process on the excitation energy of the 12 C + 40 C system, inclusive measurements were made at bombarding energies of 74, 132, 162, and 185 MeV

  12. High efficiency beam splitting for H- accelerators

    International Nuclear Information System (INIS)

    Kramer, S.L.; Stipp, V.; Krieger, C.; Madsen, J.

    1985-01-01

    Beam splitting for high energy accelerators has typically involved a significant loss of beam and radiation. This paper reports on a new method of splitting beams for H - accelerators. This technique uses a high intensity flash of light to strip a fraction of the H - beam to H 0 which are then easily separated by a small bending magnet. A system using a 900-watt (average electrical power) flashlamp and a highly efficient collector will provide 10 -3 to 10 -2 splitting of a 50 MeV H - beam. Results on the operation and comparisons with stripping cross sections are presented. Also discussed is the possibility for developing this system to yield a higher stripping fraction

  13. Hands-on repair of component with a lowered pool water level

    International Nuclear Information System (INIS)

    Perfect, J.F.

    1984-01-01

    The repair of a broken positioner mechanism on a TRIGA Reactor neutron collimator, with a lowered pool water level, presented a unique challenge. Radiation dose measurements were made which indicated the repair could be done safely with only 3 feet of water providing shielding over the reactor core. The entire repair project went quite well, due in large part to extensive preplanning. Repair was done safely and radiation exposures were kept well below allowable levels. Savings were significant using this method of repair compared to the alternative of dismantling the facility. (author)

  14. Hands-on repair of component with a lowered pool water level

    International Nuclear Information System (INIS)

    Perfect, J.F.

    1984-01-01

    The repair of a broken positioner mechanism on a TRIGA Reactor neutron collimator, with a lowered pool water level, presented a unique challenge. Radiation dose measurements were made which indicated the repair could be done safetly with only 3 feet of water providing shielding over the reactor core. The entire repair project went quite well, due in large part to extensive preplanning. Repair was done safely and radiation exposures were kept well below allowable levels. Savings were significant using this method of repair compared to the alternative of dismantling the facility

  15. Repair of potentially lethal damage in unfed plateau phase cultures of Ehrlich ascited tumour cells

    International Nuclear Information System (INIS)

    Illiakis, G.

    1980-01-01

    Plateau phase EAT-cells have been irradiated at different times in the plateau phase and their ability to repair PLD has been measured. A large capacity to repair PLD has been observed if the cultures were kept in the plateau phase for some hours after irradiation before diluting and plating to measure the survival. In combination with theoretical considerations it is concluded that almost all the PLD produced under these conditions can be repaired. The reaction rate of this repair was independent of the dose and the age of the culture. The results also indicate that PLD repair is independent of the intercellular contact of EAT-cells. (author)

  16. Electroweak splitting functions and high energy showering

    Science.gov (United States)

    Chen, Junmou; Han, Tao; Tweedie, Brock

    2017-11-01

    We derive the electroweak (EW) collinear splitting functions for the Standard Model, including the massive fermions, gauge bosons and the Higgs boson. We first present the splitting functions in the limit of unbroken SU(2) L × U(1) Y and discuss their general features in the collinear and soft-collinear regimes. These are the leading contributions at a splitting scale ( k T ) far above the EW scale ( v). We then systematically incorporate EW symmetry breaking (EWSB), which leads to the emergence of additional "ultra-collinear" splitting phenomena and naive violations of the Goldstone-boson Equivalence Theorem. We suggest a particularly convenient choice of non-covariant gauge (dubbed "Goldstone Equivalence Gauge") that disentangles the effects of Goldstone bosons and gauge fields in the presence of EWSB, and allows trivial book-keeping of leading power corrections in v/ k T . We implement a comprehensive, practical EW showering scheme based on these splitting functions using a Sudakov evolution formalism. Novel features in the implementation include a complete accounting of ultra-collinear effects, matching between shower and decay, kinematic back-reaction corrections in multi-stage showers, and mixed-state evolution of neutral bosons ( γ/ Z/ h) using density-matrices. We employ the EW showering formalism to study a number of important physical processes at O (1-10 TeV) energies. They include (a) electroweak partons in the initial state as the basis for vector-boson-fusion; (b) the emergence of "weak jets" such as those initiated by transverse gauge bosons, with individual splitting probabilities as large as O (35%); (c) EW showers initiated by top quarks, including Higgs bosons in the final state; (d) the occurrence of O (1) interference effects within EW showers involving the neutral bosons; and (e) EW corrections to new physics processes, as illustrated by production of a heavy vector boson ( W ') and the subsequent showering of its decay products.

  17. DNA-repair synthesis in ataxia telangiectasia lymphoblastoid cells

    Energy Technology Data Exchange (ETDEWEB)

    Ford, M.D.; Houldsworth, J.; Lavin, M.F. (Queensland Univ., Brisbane (Australia). Dept. of Biochemistry)

    1981-12-01

    The ability of a number of Epstein-Barr virus-transformed lymphoblastoid cells from ataxia telangiectasia (AT) patients to repair ..gamma..-radiation damage to DNA was determined. All of these AT cells were previously shown to be hypersensitive to ..gamma..-radiation. Two methods were used to determine DNA-repair synthesis: isopycnic gradient analysis and a method employing hydroxyurea to inhibit semiconservative DNA synthesis. Control, AT heterozygote and AT homozygote cells were demonstrated to have similar capacities for repair of radiation damage to DNA. In addition at high radiation doses (10-40 krad) the extent of inhibition of DNA synthesis was similar in the different cell types.

  18. Repair of radiation injury by transplantation of hemopoietic tissue

    International Nuclear Information System (INIS)

    Smith, L.H.

    1978-01-01

    The following topics are discussed: endogenous repair of tissue by surviving cells; exogenous repair by transplantation of tissue from unirradiated donor; repair of hematopoietic tissue following sublethal exposure or exposure in the LD 1 to LD 100 range; early studies on regeneration of hematopoietic tissue in x-irradiated dogs by giving bone marrow; hypotheses as to how bone marrow injections result in regeneration of blood-forming tissue; effects of rat bone marrow transplants on survival of lethally irradiated mice; and effect of tissue transplants on dose-response curve

  19. Splitting Strategy for Simulating Genetic Regulatory Networks

    Directory of Open Access Journals (Sweden)

    Xiong You

    2014-01-01

    Full Text Available The splitting approach is developed for the numerical simulation of genetic regulatory networks with a stable steady-state structure. The numerical results of the simulation of a one-gene network, a two-gene network, and a p53-mdm2 network show that the new splitting methods constructed in this paper are remarkably more effective and more suitable for long-term computation with large steps than the traditional general-purpose Runge-Kutta methods. The new methods have no restriction on the choice of stepsize due to their infinitely large stability regions.

  20. On geometrical splitting in nonanalog Monte Carlo

    International Nuclear Information System (INIS)

    Lux, I.

    1985-01-01

    A very general geometrical procedure is considered, and it is shown how the free flights, the statistical weights and the contribution of particles participating in splitting are to be chosen in order to reach unbiased estimates in games where the transition kernels are nonanalog. Equations governing the second moment of the score and the number of flights to be stimulated are derived. It is shown that the post-splitting weights of the fragments are to be chosen equal to reach maximum gain in variance. Conditions are derived under which the expected number of flights remains finite. Simplified example illustrate the optimization of the procedure (author)

  1. Reversible perspective and splitting in time.

    Science.gov (United States)

    Hart, Helen Schoenhals

    2012-01-01

    The element of time--the experience of it and the defensive use of it--is explored in conjunction with the use of reversible perspective as a psychotic defense. Clinical material from a long analysis illustrates how a psychotic patient used the reversible perspective, with its static splitting, to abolish the experience of time. When he improved and the reversible perspective became less effective for him, he replaced it with a more dynamic splitting mechanism using time gaps. With further improvement, the patient began to experience the passage of time, and along with it the excruciating pain of separation, envy, and loss.

  2. Resistance to radiation, recombination, repair of DNA and chromosome organisation

    International Nuclear Information System (INIS)

    Fletcher, H.L.

    1981-01-01

    The model advanced here proposes that death is caused by destructive lesions, mainly double-strand breaks, in all the inter-repairable copies so close together that recombination repair cannot function. Death is related to the exponential of dose where r is the number of copies of the genome. A graph of ln(-ln survival) against ln dose is used to produce a linear dose-survival relationship, the slope of which gives the number of inter-repairable copies of the genome (= number of hits per lethal event). In Ustilago maydis it seems that unless all the chromatids are broken within a few thousand base pairs all ds breaks are repaired. The size of this critical target is similar to the size of a gene. Meiotic pairing in fungi starts outside the genes, and it is therefore suggested that specific pairing sites between genes define the ends of the targets. The model also describes the radiation-induced death of Micrococcus radiodurans and Sacchromyces cerevisiae. Cultured mammalian cells also show a linear ln(-ln survival)/ln dose relationship with a slope of 1.5 showing that both 1st and 2nd order killing occured. Sublethal radiation induces recombination in heterozygous diploid U. maydis proportional to the square of the dose. Sister-chromatid repair is preferred. Polyploid yeast can only use pairs of chromosomes for repair, showing that chromosome pairing is required for recombination repair, and mitotic pairing is restricted to bivalents in the same way that meiotic pairing is. (orig./AJ)

  3. Resistance to radiation, recombination, repair of DNA and chromosome organisation

    Energy Technology Data Exchange (ETDEWEB)

    Fletcher, H L [East Anglia Univ., Norwich (UK). School of Biological Sciences

    1981-01-01

    The model advanced here proposes that death is caused by destructive lesions, mainly double-strand breaks, in all the inter-repairable copies so close together that recombination repair cannot function. Death is related to the exponential of dose where r is the number of copies of the genome. A graph of ln(-ln survival) against ln dose is used to produce a linear dose-survival relationship, the slope of which gives the number of inter-repairable copies of the genome (= number of hits per lethal event). In Ustilago maydis it seems that unless all the chromatids are broken within a few thousand base pairs all ds breaks are repaired. The size of this critical target is similar to the size of a gene. Meiotic pairing in fungi starts outside the genes, and it is therefore suggested that specific pairing sites between genes define the ends of the targets. The model also describes the radiation-induced death of Micrococcus radiodurans and Sacchromyces cerevisiae. Cultured mammalian cells also show a linear ln(-ln survival)/ln dose relationship with a slope of 1.5 showing that both 1st and 2nd order killing occured. Sublethal radiation induces recombination in heterozygous diploid U. maydis proportional to the square of the dose. Sister-chromatid repair is preferred. Polyploid yeast can only use pairs of chromosomes for repair, showing that chromosome pairing is required for recombination repair, and mitotic pairing is restricted to bivalents in the same way that meiotic pairing is.

  4. Accelerated split course regimen in the treatment of brain metastases

    International Nuclear Information System (INIS)

    Franchin, G.; Minatel, E.; Roncadin, M.; Trovo, M.G.; De Paoli, A.; Bortolus, R.; Arcicasa, M.; Boz, G.; Gobitti, C.; Grigoletto, E.; Bassignano, G.

    1988-01-01

    63 patients, with brain metastases were treated with an accelerated split course regimen; irradiation was given to the whole brain in 3 daily fractions of 160 cGy each for 5 days a week. The cycle was repeated after 2 weeks to a total dose of 4800 cGy. Male-female ratio was 3:1. Median age was 58 years. The most frequent site of primary tumor was lung (41 patients), breast in 6 patients, melanoma in 3 patients, other sites in 8 patients and unknown cancer in 5 patients. Thirty-five patients had multiple brain metastases localizations. Two patients failed to complete the scheduled treatment: one because of early death and the other by refusal of therapy during treatment. Complete remission was obtained in 4 patients and partial remission in 24 patients. The median survival time was 21 weeks. The overall response rate was 42.5%. Toxicity was not considerable. The treatment results were not influenced by the site of primary tumor or by disease spreading; only the neurologic status before radiotherapy and the response to treatment influenced survival. The results obtained are similar to those reported by others; however, with the accelerated split course regimen the treatment time was reduced and a shorter period of hospitalization was required. 36 refs.; 2 figs.; 3 tabs

  5. Bad splits in bilateral sagittal split osteotomy: systematic review of fracture patterns.

    Science.gov (United States)

    Steenen, S A; Becking, A G

    2016-07-01

    An unfavourable and unanticipated pattern of the mandibular sagittal split osteotomy is generally referred to as a 'bad split'. Few restorative techniques to manage the situation have been described. In this article, a classification of reported bad split pattern types is proposed and appropriate salvage procedures to manage the different types of undesired fracture are presented. A systematic review was undertaken, yielding a total of 33 studies published between 1971 and 2015. These reported a total of 458 cases of bad splits among 19,527 sagittal ramus osteotomies in 10,271 patients. The total reported incidence of bad split was 2.3% of sagittal splits. The most frequently encountered were buccal plate fractures of the proximal segment (types 1A-F) and lingual fractures of the distal segment (types 2A and 2B). Coronoid fractures (type 3) and condylar neck fractures (type 4) have seldom been reported. The various types of bad split may require different salvage approaches. Copyright © 2016 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  6. DETECTION OF FLUX EMERGENCE, SPLITTING, MERGING, AND CANCELLATION OF NETWORK FIELD. I. SPLITTING AND MERGING

    Energy Technology Data Exchange (ETDEWEB)

    Iida, Y.; Yokoyama, T. [Department of Earth and Planetary Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Hagenaar, H. J. [Lockheed Martin Advanced Technology Center, Org. ADBS, Building 252, 3251 Hanover Street, Palo Alto, CA 94304 (United States)

    2012-06-20

    Frequencies of magnetic patch processes on the supergranule boundary, namely, flux emergence, splitting, merging, and cancellation, are investigated through automatic detection. We use a set of line-of-sight magnetograms taken by the Solar Optical Telescope (SOT) on board the Hinode satellite. We found 1636 positive patches and 1637 negative patches in the data set, whose time duration is 3.5 hr and field of view is 112'' Multiplication-Sign 112''. The total numbers of magnetic processes are as follows: 493 positive and 482 negative splittings, 536 positive and 535 negative mergings, 86 cancellations, and 3 emergences. The total numbers of emergence and cancellation are significantly smaller than those of splitting and merging. Further, the frequency dependence of the merging and splitting processes on the flux content are investigated. Merging has a weak dependence on the flux content with a power-law index of only 0.28. The timescale for splitting is found to be independent of the parent flux content before splitting, which corresponds to {approx}33 minutes. It is also found that patches split into any flux contents with the same probability. This splitting has a power-law distribution of the flux content with an index of -2 as a time-independent solution. These results support that the frequency distribution of the flux content in the analyzed flux range is rapidly maintained by merging and splitting, namely, surface processes. We suggest a model for frequency distributions of cancellation and emergence based on this idea.

  7. The split delivery capacitated team orienteering problem

    NARCIS (Netherlands)

    Archetti, C.; Bianchessi, N.; Speranza, M. G.; Hertz, A.

    2014-01-01

    In this article, we study the capacitated team orienteering problem where split deliveries are allowed. A set of potential customers is given, each associated with a demand and a profit. The set of customers to be served by a fleet of capacitated vehicles has to be identified in such a way that the

  8. Basic dynamics of split Stirling refrigerators

    NARCIS (Netherlands)

    Waele, de A.T.A.M.; Liang, W.

    2008-01-01

    The basic features of the split Stirling refrigerator, driven by a linear compressor, are described. Friction of the compressor piston and of the regenerator, and the viscous losses due to the gas flow through the regenerator matrix are taken into account. The temp. at the cold end is an input

  9. "Split Cast Mounting: Review and New Technique".

    Science.gov (United States)

    Gundawar, S M; Pande, Neelam A; Jaiswal, Priti; Radke, U M

    2014-12-01

    For the fabrication of a prosthesis, the Prosthodontist meticulously performs all the steps. The laboratory technician then make every effort/strives to perform the remaining lab procedures. However when the processed dentures are remounted on the articulator, some changes are seen. These changes may be divided into two categories: Pre-insertion and post-insertion changes, which deal with the physical properties of the materials involved (Parker, J Prosthet Dent 31:335-342, 1974). Split cast mounting is the method of mounting casts on the articulator. It is essentially a maxillary cast constructed in two parts with a horizontal division. The procedure allows for the verification of the accuracy of the initial mounting and the ease of removal and replacement of the cast. This provides a precise means of correcting the changes in occlusion occurring as a result of the processing technique (Nogueira et al., J Prosthet Dent 91:386-388, 2004). Instability of the split mounting has always been a problem to the Prosthodontist thereby limiting its use. There are various materials mentioned in the literature. The new technique by using Dowel pins and twill thread is very easy, cheaper and simple way to stabilize the split mounting. It is useful and easy in day to day laboratory procedures. The article presents different methods of split cast mounting and the new procedure using easily available materials in prosthetic laboratory.

  10. Splitting up Beta’s change

    OpenAIRE

    Suarez, Ronny

    2014-01-01

    In this paper we estimated IBM beta from 2000 to 2013, then using differential equation mathematical formula we split up the annual beta’s change attributed to the volatility market effect, the stock volatility effect, the correlation effect and the jointly effect of these variables.

  11. Czech, Slovak science ten years after split

    CERN Multimedia

    2003-01-01

    Ten years after the split of Czechoslovakia Czech and Slovak science are facing the same difficulties: shortage of money for research, poor salaries, obsolete equipment and brain drain, especially of the young, according to a feature in the Daily Lidove Noviny (1 page).

  12. Forced splitting of fractions in CE

    NARCIS (Netherlands)

    Zalewski, D.R.; Schlautmann, Stefan; Gardeniers, Johannes G.E.

    2008-01-01

    In order to increase the electrophoretic separation between fractions of analytes on a microfluidic chip, without the need for a longer separation channel, we propose and demonstrate a preparative electrokinetic procedure by which overlapping or closely spaced fractions are automatically split. The

  13. The Split sudâmja

    Directory of Open Access Journals (Sweden)

    Petar Šimunović

    1991-12-01

    Full Text Available The name of the Split feast Sudamja!Sudajma ("festa sancti Domnii" has not yet been adequately explained. The author believes that the name originated from the Old Dalmatian adjective san(ctu + Domnĭu. In the adjective santu the cluster /an/ in front of·a consonant gave in Croatian the back nasal /q/ pronounced until the end of the 10th century and giving /u/ after that. In this way the forms *Sudumja and similar originated. The short stressed /u/ in the closed syllable was percieved by the Croatian folk as their semivowel which later gave /a/ = Sudamja. The author connects this feature with that in the toponimes Makar ( /jm/ is well known in Croatian dialectology (sumja > sujma, and it resembles the metatheses which occurs in the Split toponimes: Sukošjân > Sukojšãn ( < *santu Cassianu, Pojišân/Pojšiin (< *pasianu < Pansianu. The author finds the same feature in the toponime Dumjača (: *Dumi- + -ača. He considers these features as Croatian popular adaptations which have not occured in the personal name Dujam, the toponime Dujmovača "terrae s. Domnii" and in the adjective sandujamski, because of the link with the saint's name Domnio!Duymo etc., which has been well liked and is frequent as name of Split Romas as well as Croats from the foundation of Split, has never been broken.

  14. Hyperfine splitting in ordinary and muonic hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Tomalak, Oleksandr [Johannes Gutenberg Universitaet, Institut fuer Kernphysik and PRISMA Cluster of Excellence, Mainz (Germany)

    2018-01-15

    We provide an accurate evaluation of the two-photon exchange correction to the hyperfine splitting of S energy levels in muonic hydrogen exploiting the corresponding measurements in electronic hydrogen. The proton structure uncertainty in the calculation of α{sup 5} contribution is sizably reduced. (orig.)

  15. Source splitting via the point source method

    International Nuclear Information System (INIS)

    Potthast, Roland; Fazi, Filippo M; Nelson, Philip A

    2010-01-01

    We introduce a new algorithm for source identification and field splitting based on the point source method (Potthast 1998 A point-source method for inverse acoustic and electromagnetic obstacle scattering problems IMA J. Appl. Math. 61 119–40, Potthast R 1996 A fast new method to solve inverse scattering problems Inverse Problems 12 731–42). The task is to separate the sound fields u j , j = 1, ..., n of n element of N sound sources supported in different bounded domains G 1 , ..., G n in R 3 from measurements of the field on some microphone array—mathematically speaking from the knowledge of the sum of the fields u = u 1 + ... + u n on some open subset Λ of a plane. The main idea of the scheme is to calculate filter functions g 1 ,…, g n , n element of N, to construct u l for l = 1, ..., n from u| Λ in the form u l (x) = ∫ Λ g l,x (y)u(y)ds(y), l=1,... n. (1) We will provide the complete mathematical theory for the field splitting via the point source method. In particular, we describe uniqueness, solvability of the problem and convergence and stability of the algorithm. In the second part we describe the practical realization of the splitting for real data measurements carried out at the Institute for Sound and Vibration Research at Southampton, UK. A practical demonstration of the original recording and the splitting results for real data is available online

  16. Split Coil Forms for Rotary Transformers

    Science.gov (United States)

    Mclyman, C. W. T.

    1982-01-01

    Split cores for rotor and stator windings of rotary transformer mounted around their respective coils (which are in bobbins) and cemented together. This arrangement simplifies winding of stator coil to go in a slot in inner diameter of stator coil. One practical application of rotary transformers fabricated according to this technique is for centrifuges, in which conventional sliprings are of uncertain reliability.

  17. Split heat pipe heat recovery system

    OpenAIRE

    E. Azad

    2008-01-01

    This paper describes a theoretical analysis of a split heat pipe heat recovery system. The analysis is based on an Effectiveness-NTU approach to deduce its heat transfer characteristics. In this study the variation of overall effectiveness of heat recovery with the number of transfer units are presented. Copyright , Manchester University Press.

  18. Split brain : Divided perception but undivided consciousness

    NARCIS (Netherlands)

    Pinto, Y.; Neville, D.A.; Otten, M.; Corballis, P.M.; Lamme, V.A.F.; de Haan, E.H.F.; Foschi, N.; Fabri, M.

    In extensive studies with two split-brain patients we replicate the standard finding that stimuli cannot be compared across visual half-fields, indicating that each hemisphere processes information independently of the other. Yet, crucially, we show that the canonical textbook findings that a

  19. Split brain: divided perception but undivided consciousness.

    Science.gov (United States)

    Pinto, Yair; Neville, David A; Otten, Marte; Corballis, Paul M; Lamme, Victor A F; de Haan, Edward H F; Foschi, Nicoletta; Fabri, Mara

    2017-05-01

    In extensive studies with two split-brain patients we replicate the standard finding that stimuli cannot be compared across visual half-fields, indicating that each hemisphere processes information independently of the other. Yet, crucially, we show that the canonical textbook findings that a split-brain patient can only respond to stimuli in the left visual half-field with the left hand, and to stimuli in the right visual half-field with the right hand and verbally, are not universally true. Across a wide variety of tasks, split-brain patients with a complete and radiologically confirmed transection of the corpus callosum showed full awareness of presence, and well above chance-level recognition of location, orientation and identity of stimuli throughout the entire visual field, irrespective of response type (left hand, right hand, or verbally). Crucially, we used confidence ratings to assess conscious awareness. This revealed that also on high confidence trials, indicative of conscious perception, response type did not affect performance. These findings suggest that severing the cortical connections between hemispheres splits visual perception, but does not create two independent conscious perceivers within one brain. © The Author (2017). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. Helioseismic Solar Cycle Changes and Splitting Coefficients

    Indian Academy of Sciences (India)

    tribpo

    Abstract. Using the GONG data for a period over four years, we have studied the variation of frequencies and splitting coefficients with solar cycle. Frequencies and even-order coefficients are found to change signi- ficantly with rising phase of the solar cycle. We also find temporal varia- tions in the rotation rate near the solar ...

  1. The practice and clinical implications of tablet splitting in international health

    Science.gov (United States)

    Elliott, Ivo; Mayxay, Mayfong; Yeuichaixong, Sengchanh; Lee, Sue J; Newton, Paul N

    2014-01-01

    Objective Tablet splitting is frequently performed to facilitate correct dosing, but the practice and implications in low-income settings have rarely been discussed. Methods We selected eight drugs, with narrow therapeutic indices or critical dosages, frequently divided in the Lao PDR (Laos). These were split, by common techniques used in Laos, by four nurses and four laypersons. The mean percentage deviation from the theoretical expected weight and weight loss of divided tablets/capsules were recorded. Results Five of eight study drugs failed, on splitting, to meet European Pharmacopoeia recommendations for tablet weight deviation from the expected weight of tablet/capsule halves with 10% deviating by more than 25%. There was a significant difference in splitting accuracy between nurses and laypersons (P = 0.027). Coated and unscored tablets were less accurately split than uncoated (P = 0.03 and 0.0019 for each half) and scored (0.0001 for both halves) tablets. Conclusion These findings have potential clinical implications on treatment outcome and the development of antimicrobial resistance. Investment by drug companies in a wider range of dosage units, particularly for narrow therapeutic index and critical dosage medicines, is strongly recommended. PMID:24702766

  2. Pyrimidine dimer formation and repair in human skin

    International Nuclear Information System (INIS)

    Sutherland, B.M.; Harber, L.C.; Kochevar, I.E.

    1980-01-01

    Cyclobutyl pyrimidine dimers have been detected in the DNA of human skin following in vivo irradiation with suberythermal doses of ultraviolet (UV) radiation from FS-20 sun lamp fluorescent tubes. Dimers were assayed by treatment of extracted DNA with Micrococus luteus UV-specific endonuclease, alkaline agarose electrophoresis, and ethidum bromide staining. This technique, in contrast to conventional dimer assays, can be used with nonradioactive DNA and is optimal at low UV light doses. These data suggest that some dimer disappearance by excision repair occurs within 20 min of UV irradiation and that photoreactivation of dimers can make a contribution to the total repair process

  3. Radiobiological significance of DNA repair

    International Nuclear Information System (INIS)

    Kuzin, A.M.

    1978-01-01

    A short outline is given on the history of the problem relating to the repair of radiation injuries, specifically its molecular mechanisms. The most urgent problems which currently confront the researchers are noted. This is a further study on the role of DNA repair in post-radiation recovery, search for ways to activate and suppress DNA repair, investigations into the activity balance of various repair enzymes as well as the problem of errors in the structure of repairing DNA. An important role is attached to the investigations of DNA repair in solving a number of practical problems

  4. Recombinational repair: workshop summary

    International Nuclear Information System (INIS)

    Howard-Flanders, P.

    1983-01-01

    Recombinational repair may or may not be synonymous with postreplication repair. Considerable progress has been made in the study of the relevant enzymes, particularly those from bacteria. In this workshop we focus on the recombination enzyme RecA protein. What structural changes take place in the protein and in DNA during repair. How does homologous pairing take place. How is ATP hydrolysis coupled to the stand exchange reaction and the formation of heteroduplx DNA. Turning to another enzyme needed for certain kinds of bacterial recombination, we will ask whether the purified recB protein and recC protein complement each other and are sufficient for exonuclease V activity. In higher cells, we would like to know whether sister exchanges, which occur in bacteria after uv irradiation, are also seen in animal cells

  5. The Split-Brain Phenomenon Revisited: A Single Conscious Agent with Split Perception.

    Science.gov (United States)

    Pinto, Yair; de Haan, Edward H F; Lamme, Victor A F

    2017-11-01

    The split-brain phenomenon is caused by the surgical severing of the corpus callosum, the main route of communication between the cerebral hemispheres. The classical view of this syndrome asserts that conscious unity is abolished. The left hemisphere consciously experiences and functions independently of the right hemisphere. This view is a cornerstone of current consciousness research. In this review, we first discuss the evidence for the classical view. We then propose an alternative, the 'conscious unity, split perception' model. This model asserts that a split brain produces one conscious agent who experiences two parallel, unintegrated streams of information. In addition to changing our view of the split-brain phenomenon, this new model also poses a serious challenge for current dominant theories of consciousness. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Meniscal repair devices.

    Science.gov (United States)

    Barber, F A; Herbert, M A

    2000-09-01

    Meniscal repair devices not requiring accessory incisions are attractive. Many factors contribute to their clinical effectiveness including their biomechanical characteristics. This study compared several new meniscal repair devices with standard meniscal suture techniques. Using a porcine model, axis-of-insertion loads were applied to various meniscal sutures and repair devices. A single device or stitch was placed in a created meniscal tear and a load applied. Both loads and modes of failure were recorded. The load-to-failure data show stratification into 4 distinct statistical groups. Group A, 113 N for a double vertical stitch; group B, 80 N for a single vertical stitch; group C, 57 N for the BioStinger, 56 N for a horizontal mattress stitch, and 50 N for the T-Fix stitch; and group D, 33 N for the Meniscus Arrow (inserted by hand or gun), 32 N for the Clearfix screw, 31 N for the SDsorb staple, 30 N for the Mitek meniscal repair system, and 27 N for the Biomet staple. The failure mechanism varied. Sutures broke away from the knot. The Meniscus Arrow and BioStinger pulled through the inner rim with the crossbar intact. The Clearfix screw failed by multiple mechanisms, whereas 1 leg of the SDsorb staple always pulled out of the outer rim. The Mitek device usually failed by pullout from the inner rim. The Biomet staple always broke at the crosshead or just below it. Although the surgeon should be aware of the material properties of the repair technique chosen for a meniscal repair, this information is only an indication of device performance and may not correlate with clinical healing results.

  7. DNA repair and cancer

    International Nuclear Information System (INIS)

    Rathore, Shakuntla; Joshi, Pankaj Kumar; Gaur, Sudha

    2012-01-01

    DNA repair refers to a collection of processes by which a cell identifies and corrects damage to the DNA molecule that encode it's genome. In human cells, both normal metabolic activities and environmental factors such as UV light and radiation can cause DNA damage, resulting in as many one million individual molecular lesions per day. Many of these lesions cause structural damage to the DNA molecule and can alter or eliminate the cell's ability to transcribe the gene that the affected DNA encodes. Other lesions include potentially harmful mutation in cell's genome which affect the survival of it's daughter cells after it undergoes mitosis. As a consequence, the DNA repair process is constantly active as it responds to damage in the DNA structure. Inherited mutation that affect DNA repair genes are strongly associated with high cancer risks in humans. Hereditary non polyposis colorectal cancer (HNPCC) is strongly associated with specific mutation in the DNA mismatch repair pathway. BRCA1, BRCA2 two famous mutation conferring a hugely increased risk of breast cancer on carrier, are both associated with a large number of DNA repair pathway, especially NHEJ and homologous recombination. Cancer therapy procedures such as chemotherapy and radiotherapy work by overwhelming the capacity of the cell to repair DNA damage, resulting in cell death. Cells that are most rapidly dividing most typically cancer cells are preferentially affected. The side effect is that other non-cancerous but rapidly dividing cells such as stem cells in the bone marrow are also affected. Modern cancer treatment attempt to localize the DNA damage to cells and tissue only associated with cancer, either by physical means (concentrating the therapeutic agent in the region of the tumor) or by biochemical means (exploiting a feature unique to cancer cells in the body). (author)

  8. Pulse frequency in pulsed brachytherapy based on tissue repair kinetics

    International Nuclear Information System (INIS)

    Sminia, Peter; Schneider, Christoph J.; Koedooder, Kees; Tienhoven, Geertjan van; Blank, Leo E.C.M.; Gonzalez Gonzalez, Dionisio

    1998-01-01

    Purpose: Investigation of normal tissue sparing in pulsed brachytherapy (PB) relative to continuous low-dose rate irradiation (CLDR) by adjusting pulse frequency based on tissue repair characteristics. Method: Using the linear quadratic model, the relative effectiveness (RE) of a 20 Gy boost was calculated for tissue with an α/β ratio ranging from 2 to 10 Gy and a half-time of sublethal damage repair between 0.1 and 3 h. The boost dose was considered to be delivered either in a number of pulses varying from 2 to 25, or continuously at a dose rate of 0.50, 0.80, or 1.20 Gy/h. Results: The RE of 20 Gy was found to be identical for PB in 25 pulses of 0.80 Gy each h and CLDR delivered at 0.80 Gy/h for any α/β value and for a repair half-time > 0.75 h. When normal tissue repair half-times are assumed to be longer than tumor repair half-times, normal tissue sparing can be obtained, within the restriction of a fixed overall treatment time, with higher dose per pulse and longer period time (time elapsed between start of pulse n and start of pulse n + 1). An optimum relative normal tissue sparing larger than 10% was found with 4 pulses of 5 Gy every 8 h. Hence, a therapeutic gain might be obtained when changing from CLDR to PB by adjusting the physical dose in such a way that the biological dose on the tumor is maintained. The normal tissue-sparing phenomenon can be explained by an increase in RE with longer period time for tissue with high α/β ratio and fast or intermediate repair half-time, and the RE for tissue with low α/β ratio and long repair half-time remains almost constant. Conclusion: Within the benchmark of the LQ model, advantage in normal tissue-sparing is expected when matching the pulse frequency to the repair kinetics of the normal tissue exposed. A period time longer than 1 h may lead to a reduction of late normal tissue complications. This theoretical advantage emphasizes the need for better knowledge of human tissue-repair kinetics

  9. Biological radiolesions and repair

    International Nuclear Information System (INIS)

    Laskowski, W.

    1981-01-01

    In 7 chapters, the book answers the following questions: 1) What reactions are induced in biological matter by absorption of radiation energy. 2) In what parts of the cell do the radiation-induced reactions with detectable biological effects occur. 3) In which way are these cell components changed by different qualities of radiation. 4) What are the cell mechanisms by which radiation-induced changes can be repaired. 5) What is the importance of these repair processes for man, his life and evolution. At the end of each chapter, there is a bibliography of relevant publications in this field. (orig./MG) [de

  10. Repair promoted by plasmid pKM101 is different from SOS repair

    International Nuclear Information System (INIS)

    Goze, A.; Devoret, R.

    1979-01-01

    In E. coli K12 bacteria carrying plasmid pKM101, prophage lambda was induced at UV doses higher than in plasmid-less parental bacteria. UV-induced reactivation per se was less effective. Bacteria with pKM101 showed no alteration in their division cycle. Plasmid PKM101 coded for a constitutive error-prone repair different from the inducible error-prone repair called SOS repair. Plasmid pKM101 protected E. coli bacteria from UV damage but slightly sensitized them to X-ray lesions. Protection against UV damage was effective in mutant bacteria deficient in DNA excision-repair provided that the recA, lexA and uvrE genes were functional. Survival of phages lambda and S13 after UV irradiation was enhanced in bacteria carrying plasmid pKM101; phage lambda mutagenesis was also increased. Plasmid pKM101 repaired potentially lethal DNA lesions, although Wild-type DNA sequences may not necessarily be restored; hence the mutations observed are the traces of the original DNA lesions. (Auth.)

  11. DNA repair in human cells exposed to combinations of carcinogenic agents

    International Nuclear Information System (INIS)

    Setlow, R.B.; Ahmed, F.E.

    1980-01-01

    Normal human and XP 2 fibroblasts were treated with uv plus uv-mimetic chemicals. The uv dose used was sufficient to saturate the uv excision repair system. Excision repair after combined treatments was estimated by unscheduled DNA synthesis, BrdUrd photolysis, and the loss of sites sensitive to a uv specific endonuclease. Since the repair of damage from uv and its mimetics is coordinately controlled we expected that there would be similar rate-limiting steps in the repair of uv and chemical damage and that after a combined treatment the total amount of repair would be the same as from uv or the chemicals separately. The expectation was not fulfilled. In normal cells repair after a combined treatment was additive whereas in XP cells repair after a combined treatment was usually less than after either agent separately. The chemicals tested were AAAF, DMBA-epoxide, 4NQO, and ICR-170

  12. Composite Repair System, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — GTL has developed an innovative composite repair methodology known as the Composite Repair System (CRS). In this phase I effort, CRS is being developed for the...

  13. About the Collision Repair Campaign

    Science.gov (United States)

    EPA developed the Collision Repair Campaign to focus on meaningful risk reduction in the Collision Repair source sector to complement ongoing community air toxics work and attain reductions at a faster rate.

  14. Vesicovaginal Fistula Repair During Pregnancy

    African Journals Online (AJOL)

    Vesicovaginal Fistula Repair During Pregnancy: A Case Report ... Abstract. We report a repair of Vesicovaginal fistula during pregnancy that was aimed at preventing another spontaneous ... practices that encourage teenage marriage and girl.

  15. Ship Repair Workflow Cost Model

    National Research Council Canada - National Science Library

    McDevitt, Mike

    2003-01-01

    The effects of intermittent work patterns and funding on the costs of ship repair and maintenance were modeled for the San Diego region in 2002 for Supervisor of Shipbuilding and Repair (SUPSHIP) San Diego...

  16. A Regularized Algorithm for the Proximal Split Feasibility Problem

    Directory of Open Access Journals (Sweden)

    Zhangsong Yao

    2014-01-01

    Full Text Available The proximal split feasibility problem has been studied. A regularized method has been presented for solving the proximal split feasibility problem. Strong convergence theorem is given.

  17. Photoelectrochemical water splitting: optimizing interfaces and light absorption

    NARCIS (Netherlands)

    Park, Sun-Young

    2015-01-01

    In this thesis several photoelectrochemical water splitting devices based on semiconductor materials were investigated. The aim was the design, characterization, and fabrication of solar-to-fuel devices which can absorb solar light and split water to produce hydrogen.

  18. Iterative group splitting algorithm for opportunistic scheduling systems

    KAUST Repository

    Nam, Haewoon; Alouini, Mohamed-Slim

    2014-01-01

    An efficient feedback algorithm for opportunistic scheduling systems based on iterative group splitting is proposed in this paper. Similar to the opportunistic splitting algorithm, the proposed algorithm adjusts (or lowers) the feedback threshold

  19. Guidelines to Develop Efficient Photocatalysts for Water Splitting

    KAUST Repository

    Garcia Esparza, Angel T.

    2016-01-01

    Photocatalytic overall water splitting is the only viable solar-to-fuel conversion technology. The research discloses an investigation process wherein by dissecting the photocatalytic water splitting device, electrocatalysts, and semiconductor

  20. Comparing Electrochemical and Biological Water Splitting

    DEFF Research Database (Denmark)

    Rossmeisl, Jan; Dimitrievski, Kristian; Siegbahn, P.

    2007-01-01

    On the basis of density functional theory calculations, we compare the free energies of key intermediates in the water splitting reaction over transition metal oxide surfaces to those of the Mn cluster in photo system II. In spite of the very different environments in the enzyme system and on the......On the basis of density functional theory calculations, we compare the free energies of key intermediates in the water splitting reaction over transition metal oxide surfaces to those of the Mn cluster in photo system II. In spite of the very different environments in the enzyme system...... and on the inorganic catalyst surface of an acidic electrolysis cell, the thermochemical features of the catalysts can be directly compared. We suggest a simple test for a thermochemically optimal catalyst. We show that, although both the RuO2 surface and the Mn cluster in photo system II are quite close to optimal...

  1. Splitting of high power, cw proton beams

    Directory of Open Access Journals (Sweden)

    Alberto Facco

    2007-09-01

    Full Text Available A simple method for splitting a high power, continuous wave (cw proton beam in two or more branches with low losses has been developed in the framework of the EURISOL (European Isotope Separation On-Line Radioactive Ion Beam Facility design study. The aim of the system is to deliver up to 4 MW of H^{-} beam to the main radioactive ion beam production target, and up to 100 kW of proton beams to three more targets, simultaneously. A three-step method is used, which includes magnetic neutralization of a fraction of the main H^{-} beam, magnetic splitting of H^{-} and H^{0}, and stripping of H^{0} to H^{+}. The method allows slow raising and individual fine adjustment of the beam intensity in each branch.

  2. Temporal self-splitting of optical pulses

    Science.gov (United States)

    Ding, Chaoliang; Koivurova, Matias; Turunen, Jari; Pan, Liuzhan

    2018-05-01

    We present mathematical models for temporally and spectrally partially coherent pulse trains with Laguerre-Gaussian and Hermite-Gaussian Schell-model statistics as extensions of the standard Gaussian Schell model for pulse trains. We derive propagation formulas of both classes of pulsed fields in linearly dispersive media and in temporal optical systems. It is found that, in general, both types of fields exhibit time-domain self-splitting upon propagation. The Laguerre-Gaussian model leads to multiply peaked pulses, while the Hermite-Gaussian model leads to doubly peaked pulses, in the temporal far field (in dispersive media) or at the Fourier plane of a temporal system. In both model fields the character of the self-splitting phenomenon depends both on the degree of temporal and spectral coherence and on the power spectrum of the field.

  3. Solar Water Splitting Using Semiconductor Photocatalyst Powders

    KAUST Repository

    Takanabe, Kazuhiro

    2015-07-01

    Solar energy conversion is essential to address the gap between energy production and increasing demand. Large scale energy generation from solar energy can only be achieved through equally large scale collection of the solar spectrum. Overall water splitting using heterogeneous photocatalysts with a single semiconductor enables the direct generation of H from photoreactors and is one of the most economical technologies for large-scale production of solar fuels. Efficient photocatalyst materials are essential to make this process feasible for future technologies. To achieve efficient photocatalysis for overall water splitting, all of the parameters involved at different time scales should be improved because the overall efficiency is obtained by the multiplication of all these fundamental efficiencies. Accumulation of knowledge ranging from solid-state physics to electrochemistry and a multidisciplinary approach to conduct various measurements are inevitable to be able to understand photocatalysis fully and to improve its efficiency.

  4. Meshed split skin graft for extensive vitiligo

    Directory of Open Access Journals (Sweden)

    Srinivas C

    2004-05-01

    Full Text Available A 30 year old female presented with generalized stable vitiligo involving large areas of the body. Since large areas were to be treated it was decided to do meshed split skin graft. A phototoxic blister over recipient site was induced by applying 8 MOP solution followed by exposure to UVA. The split skin graft was harvested from donor area by Padgett dermatome which was meshed by an ampligreffe to increase the size of the graft by 4 times. Significant pigmentation of the depigmented skin was seen after 5 months. This procedure helps to cover large recipient areas, when pigmented donor skin is limited with minimal risk of scarring. Phototoxic blister enables easy separation of epidermis thus saving time required for dermabrasion from recipient site.

  5. Timelike single-logarithm-resummed splitting functions

    Energy Technology Data Exchange (ETDEWEB)

    Albino, S.; Bolzoni, P.; Kniehl, B.A. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Kotikov, A.V. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Joint Inst. of Nuclear Research, Moscow (Russian Federation). Bogoliubov Lab. of Theoretical Physics

    2011-08-15

    We calculate the single logarithmic contributions to the quark singlet and gluon matrix of timelike splitting functions at all orders in the modified minimal-subtraction (MS) scheme. We fix two of the degrees of freedom of this matrix from the analogous results in the massive-gluon regularization scheme by using the relation between that scheme and the MS scheme. We determine this scheme transformation from the double logarithmic contributions to the timelike splitting functions and the coefficient functions of inclusive particle production in e{sup +}e{sup -} annihilation now available in both schemes. The remaining two degrees of freedom are fixed by reasonable physical assumptions. The results agree with the fixed-order results at next-to-next-to-leading order in the literature. (orig.)

  6. Large Bandgap Semiconductors for Solar Water Splitting

    DEFF Research Database (Denmark)

    Malizia, Mauro

    Photoelectrochemical water splitting represents an eco-friendly technology that could enable the production of hydrogen using water as reactant and solar energy as primary energy source. The exploitation of solar energy for the production of hydrogen would help modern society to reduce the reliance...... on fossil fuels as primary feedstock for hydrogen production and diminish the emission of greenhouse gases in the atmosphere, weakening the global warming phenomenon.The dissertation reports the development of GaP (gallium phosphide) photocathodes as a large bandgap semiconductor for photoelectrochemical...... water splitting devices having tandem design. The increase of the photovoltage produced by GaP under illumination was the main goal of this work. GaP has a bandgap of 2.25 eV and could in theory produce a photovoltage of approximately 1.7 V. Instead, the photovoltage produced by the semiconductor...

  7. Isospin breaking in octet baryon mass splittings

    Energy Technology Data Exchange (ETDEWEB)

    Horsley, R. [Edinburgh Univ. (United Kingdom). School of Physics and Astronomy; Najjar, J. [Regensburg Univ. (Germany). Institut fuer Theoretische Physik; Nakamura, Y. [RIKEN Advanced Institute for Computational Science, Kobe, Hyogo (Japan); Pleiter, D. [Forschungszentrum Juelich (Germany). Juelich Supercomputer Centre; Rakow, P.E.L. [Liverpool Univ. (United Kingdom). Theoretical Physics Division; Schierholz, G. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Zanotti, J.M. [Adelaide Univ., SA (Australia). CSSM, School of Chemistry and Physics

    2012-06-15

    Using an SU(3) flavour symmetry breaking expansion in the quark mass, we determine the QCD component of the nucleon, Sigma and Xi mass splittings of the baryon octet due to up-down (and strange) quark mass differences in terms of the kaon mass splitting. Provided the average quark mass is kept constant, the expansion coefficients in our procedure can be determined from computationally cheaper simulations with mass degenerate sea quarks and partially quenched valence quarks. Both the linear and quadratic terms in the SU(3) flavour symmetry breaking expansion are considered; it is found that the quadratic terms only change the result by a few percent, indicating that the expansion is highly convergent.

  8. Social repair of relationships

    DEFF Research Database (Denmark)

    Fahnøe, Kristian Relsted

    2017-01-01

    organisations, friends and family, and communities. These social relations are viewed as the foundation of citizenship as experienced and practised. Focusing on how two dimensions of lived citizenship, namely rights-responsibilities and belonging, are affected by the social repairs, the chapter shows how...

  9. Comprehensive Small Engine Repair.

    Science.gov (United States)

    Hires, Bill; And Others

    This curriculum guide contains the basic information needed to repair all two- and four-stroke cycle engines. The curriculum covers four areas, each consisting of one or more units of instruction that include performance objectives, suggested activities for teacher and students, information sheets, assignment sheets, job sheets, visual aids,…

  10. Patent urachus repair - slideshow

    Science.gov (United States)

    ... Drugs & Supplements Videos & Tools About MedlinePlus Show Search Search MedlinePlus GO GO About MedlinePlus Site Map FAQs Customer Support Health Topics Drugs & Supplements Videos & Tools Español You Are Here: Home → Medical Encyclopedia → Patent urachus repair - series—Normal anatomy URL of this ...

  11. Patent urachus repair

    Science.gov (United States)

    ... Drugs & Supplements Videos & Tools About MedlinePlus Show Search Search MedlinePlus GO GO About MedlinePlus Site Map FAQs Customer Support Health Topics Drugs & Supplements Videos & Tools Español You Are Here: Home → Medical Encyclopedia → Patent urachus repair URL of this page: //medlineplus.gov/ ...

  12. DNA Repair Systems

    Indian Academy of Sciences (India)

    Thanks to the pioneering research work of Lindahl, Sancar, Modrich and their colleagues, we now have an holistic awareness of how DNA damage occurs and how the damage is rectified in bacteria as well as in higher organisms including human beings. A comprehensive understanding of DNA repair has proven crucial ...

  13. Aircraft Propeller Hub Repair

    Energy Technology Data Exchange (ETDEWEB)

    Muth, Thomas R [ORNL; Peter, William H [ORNL

    2015-02-13

    The team performed a literature review, conducted residual stress measurements, performed failure analysis, and demonstrated a solid state additive manufacturing repair technique on samples removed from a scrapped propeller hub. The team evaluated multiple options for hub repair that included existing metal buildup technologies that the Federal Aviation Administration (FAA) has already embraced, such as cold spray, high velocity oxy-fuel deposition (HVOF), and plasma spray. In addition the team helped Piedmont Propulsion Systems, LLC (PPS) evaluate three potential solutions that could be deployed at different stages in the life cycle of aluminum alloy hubs, in addition to the conventional spray coating method for repair. For new hubs, a machining practice to prevent fretting with the steel drive shaft was recommended. For hubs that were refurbished with some material remaining above the minimal material condition (MMC), a silver interface applied by an electromagnetic pulse additive manufacturing method was recommended. For hubs that were at or below the MMC, a solid state additive manufacturing technique using ultrasonic welding (UW) of thin layers of 7075 aluminum to the hub interface was recommended. A cladding demonstration using the UW technique achieved mechanical bonding of the layers showing promise as a viable repair method.

  14. Role of DNA repair in repair of cytogenetic damages. Slowly repaired DNA injuries involved in cytogenetic damages repair

    International Nuclear Information System (INIS)

    Zaichkina, S.I.; Rozanova, O.M.; Aptikaev, G.F.; Ganassi, E.Eh.

    1989-01-01

    Caffeine was used to study the kinetics of cytogenetic damages repair in Chinese hamster fibroblasts. Its half-time (90 min) was shown to correlate with that of repair of slowly repaired DNA damages. The caffeine-induced increase in the number of irreparable DNA damages, attributed to inhibition of double-strand break repair, is in a quantitative correlation with the effect of the cytogenetic damage modification

  15. Atom beams split by gentle persuasion

    International Nuclear Information System (INIS)

    Pool, R.

    1994-01-01

    Two different research teams have taken a big step toward atom interferometry. They have succeeded in splitting atomic beams by using atoms in spin states that neither absorb nor reemit laser light. By proper adjustment of experimental conditions, atoms are changed from one spin state to another, without passing through the intermediary excited state. The atoms in essence absorb momentum from the laser photons, without absorption or emission of photons. The change in momentum deflects atoms in the proper spin state

  16. Splitting of inviscid fluxes for real gases

    Science.gov (United States)

    Liou, Meng-Sing; Van Leer, Bram; Shuen, Jian-Shun

    1990-01-01

    Flux-vector and flux-difference splittings for the inviscid terms of the compressible flow equations are derived under the assumption of a general equation of state for a real gas in equilibrium. No necessary assumptions, approximations for auxiliary quantities are introduced. The formulas derived include several particular cases known for ideal gases and readily apply to curvilinear coordinates. Applications of the formulas in a TVD algorithm to one-dimensional shock-tube and nozzle problems show their quality and robustness.

  17. BILATERAL SAGITAL SPLIT OSTEOTOMY PADA MANDIBULA PROGNATI

    Directory of Open Access Journals (Sweden)

    Pradono Pradono

    2015-07-01

    Full Text Available A young girl 20 years old with mandibular prognathism, has been treated with orthodontics and surgical treatment in between. Mandibular set back was done intra orally 5 mm length and bilateral sagital split ramus osteotomy method. And rigid fixation was done by inserting three 2 mm bicortical screws for stabilizing the fragment. This method allowed the bony segments to heal properly and allowed the patients to function sooner.

  18. GD 358 - the demise of rotational splitting?

    International Nuclear Information System (INIS)

    Hill, J.A.

    1987-01-01

    Observations of GD 358 were obtained at the McDonald Observatory in 1982 and 1985 in order to determine its periods, stability, and rates of period change. The period structure could not be resolved, and the results indicate that GD 358 does not fit the rotational splitting model. It is suggested that if the changes in the amplitude spectra of GD 358 are due to beating of stable modes, then the number of modes must be large. 7 references

  19. Multiplet mass splitting in a gravitational field

    International Nuclear Information System (INIS)

    Maia, M.D.

    An expression for the mass splitting of particles belonging to the same spin multiplet defined in a space-time of general relativity is derived. The geometrical symmetry is a subgroup of SO(r,s), 9 >=r > 3, 5 >=s >=1, the mass operator being proportional to the second order Casimir operator of that subgroup. A brief analysis of the calculated values as compared to the experimental data is included. (Author) [pt

  20. Cost of splitting in Monte Carlo transport

    International Nuclear Information System (INIS)

    Everett, C.J.; Cashwell, E.D.

    1978-03-01

    In a simple transport problem designed to estimate transmission through a plane slab of x free paths by Monte Carlo methods, it is shown that m-splitting (m > or = 2) does not pay unless exp(x) > m(m + 3)/(m - 1). In such a case, the minimum total cost in terms of machine time is obtained as a function of m, and the optimal value of m is determined

  1. X-ray repair replication in L1210 leukemia cells

    International Nuclear Information System (INIS)

    Lee, Y.C.; Byfield, J.E.; Bennett, L.R.; Chan, P.Y.M.

    1974-01-01

    Repair replication has been studied in detail in mouse L1210 leukemia cells. A method of identifying and quantitating repair replication using a pre- and postradiation block of normal replication with cytosine arabinoside is illustrated. The method derived does not require isolation of DNA per se and appears to be satisfactory for screening for inhibitors of repair replication. Repair replication can be demonstrated at doses in the 1000-rad range in bromouridine deoxyriboside-substituted cells and at slightly higher doses in nonsubstituted cells. Drugs that are known to bind to DNA inhibit this x-ray-induced repair replication. Drugs with these properties may be identified by the methods described and compared quantitatively in their ability to inhibit this type of x-ray damage. Since these phenomena can be demonstrated for low radiation doses and at drug concentrations attainable in vivo during human cancer chemotherapy this class of anticancer agent may be worthy of closer study. Application to the L1210 leukemia system should permit comparison of in vitro and in vivo drug effects in the context of the extensive in vivo pharmacological data already available for L1210 cells. (U.S.)

  2. Transonymization as Revitalization: Old Toponyms of Split

    Directory of Open Access Journals (Sweden)

    Katarina Lozić Knezović

    2017-07-01

    Full Text Available The paper deals with ancient toponyms of Split, a city in the centre of the Croatian region of Dalmatia. Along with numerous monuments of spiritual and material culture, toponyms are part of the two-thousand-year-old city’s historical heritage. Split in particular abounds with sources that provide valuable information concerning ancient toponyms. In terms of the study and preservation of toponymy, three basic sources are crucial: the living oral tradition, written records, and old charts — mostly cadastral plans. In addition to researching, recording, documenting, and publishing Split’s ancient place names through toponomastic, geographical, and town planning studies, toponymic heritage preservation is also implemented through the direct use of the names in everyday life. One of the ways of such revitalization of Split’s ancient place names is their transonymization into the category of chrematonyms, i.e. their secondary use as names of institutions, shops, restaurants, schools, sports associations and facilities, bars and coffee shops, cemeteries, and so on. The present paper provides a classification and etymological analysis of detoponymic chrematonyms of Split. The authors propose measures to raise public awareness of the historical information conveyed by the names and raise some issues for consideration regarding further study of transonymization as a means of revitalizing local toponymic tradition.

  3. Cleft lip and palate repair

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/002979.htm Cleft lip and palate repair To use the sharing features on this ... Cheiloplasty; Cleft rhinoplasty; Palatoplasty; Tip rhinoplasty Patient Instructions Cleft lip and palate repair - discharge Images Cleft lip repair - series References ...

  4. DNA repair in human cells

    International Nuclear Information System (INIS)

    Regan, J.D.; Carrier, W.L.; Kusano, I.; Furuno-Fukushi, I.; Dunn, W.C. Jr.; Francis, A.A.; Lee, W.H.

    1982-01-01

    Our primary objective is to elucidate the molecular events in human cells when cellular macromolecules such as DNA are damaged by radiation or chemical agents. We study and characterize (i) the sequence of DNA repair events, (ii) the various modalities of repair, (iii) the genetic inhibition of repair due to mutation, (iv) the physiological inhibition of repair due to mutation, (v) the physiological inhibition of repair due to biochemical inhibitors, and (vi) the genetic basis of repair. Our ultimate goals are to (i) isolate and analyze the repair component of the mutagenic and/or carcinogenic event in human cells, and (ii) elucidate the magnitude and significance of this repair component as it impinges on the practical problems of human irradiation or exposure to actual or potential chemical mutagens and carcinogens. The significance of these studies lies in (i) the ubiquitousness of repair (most organisms, including man, have several complex repair systems), (ii) the belief that mutagenic and carcinogenic events may arise only from residual (nonrepaired) lesions or that error-prone repair systems may be the major induction mechanisms of the mutagenic or carcinogenic event, and (iii) the clear association of repair defects and highly carcinogenic disease states in man [xeroderma pigmentosum (XP)

  5. The journey of DNA repair.

    Science.gov (United States)

    Saini, Natalie

    2015-12-01

    21 years ago, the DNA Repair Enzyme was declared "Molecule of the Year". Today, we are celebrating another "year of repair", with the 2015 Nobel Prize in Chemistry being awarded to Aziz Sancar, Tomas Lindahl and Paul Modrich for their collective work on the different DNA repair pathways.

  6. Poolside inspection, repair and reconstitution of LWR fuel elements

    International Nuclear Information System (INIS)

    1993-03-01

    The purpose of the meeting was to review the state of the art in the area of poolside inspection, repair and reconstitution of light water fuel elements. In the present publication it appears that techniques of inspection, repair and reconstitution of fuel elements have been developed by fuel suppliers and are now routinely and successfully applied in many countries. For the first time, the subject of control rod poolside examination was dealt with, poolside inspection and repair of a MOX assembly were reported and the inspection and repair of WWER assemblies were examined. Compared to the results of the previous meeting, present developments in the area aim now at reaching better economics, better reliability, reduction of personal doses and waste volume. Thirty-six participants representing twelve countries attended the meeting. Fifteen papers were presented in two sessions. An abstract was prepared for each of these papers. Refs, figs, tabs, diagrams, pictures and photos

  7. On the additive splitting procedures and their computer realization

    DEFF Research Database (Denmark)

    Farago, I.; Thomsen, Per Grove; Zlatev, Z.

    2008-01-01

    Two additive splitting procedures are defined and studied in this paper. It is shown that these splitting procedures have good stability properties. Some other splitting procedures, which are traditionally used in mathematical models used in many scientific and engineering fields, are sketched. All...

  8. 7 CFR 51.2731 - U.S. Spanish Splits.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false U.S. Spanish Splits. 51.2731 Section 51.2731... STANDARDS) United States Standards for Grades of Shelled Spanish Type Peanuts Grades § 51.2731 U.S. Spanish Splits. “U.S. Spanish Splits” consists of shelled Spanish type peanut kernels which are split or broken...

  9. 26 CFR 1.7872-15 - Split-dollar loans.

    Science.gov (United States)

    2010-04-01

    ...'s death benefit proceeds, the policy's cash surrender value, or both. (ii) Payments that are only... regarding certain split-dollar term loans payable on the death of an individual, certain split-dollar term... insurance arrangement make a representation—(i) Requirement. An otherwise noncontingent payment on a split...

  10. Radiosensitivity and repair capacity of two xenografted human soft tissue sarcomas to photons and fast neutrons

    International Nuclear Information System (INIS)

    Budach, V.; Stuschke, M.; Budach, W.; Krause, U.; Streffer, C.; Sack, H.

    1989-01-01

    The radiation response, the relative biological effectiveness (RBE) and sublethal damage repair of two xenografted human soft tissue sarcomas after single doses and fractionated irradiation with 60 Co and 5.8 MeV fast neutrons are presented. (author)

  11. Split-field vs extended-field intensity-modulated radiation therapy plans for oropharyngeal cancer: Which spares the larynx? Which spares the thyroid?

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Yao; Chen, Josephine [Department of Radiation Oncology, University of California, San Francisco, San Francisco, CA (United States); Leary, Celeste I. [Department of Radiation Medicine, Oregon Health Sciences University, Portland, OR (United States); Shugard, Erin [Department of Radiation Oncology, University of California, San Francisco, San Francisco, CA (United States); Yom, Sue S., E-mail: yoms@radonc.ucsf.edu [Department of Radiation Oncology, University of California, San Francisco, San Francisco, CA (United States); Department of Otolaryngology—Head and Neck Surgery, University of California, San Francisco, San Francisco, CA (United States)

    2016-07-01

    Radiation of the low neck can be accomplished using split-field intensity-modulated radiation therapy (sf-IMRT) or extended-field intensity-modulated radiation therapy (ef-IMRT). We evaluated the effect of these treatment choices on target coverage and thyroid and larynx doses. Using data from 14 patients with cancers of the oropharynx, we compared the following 3 strategies for radiating the low neck: (1) extended-field IMRT, (2) traditional split-field IMRT with an initial cord-junction block to 40 Gy, followed by a full-cord block to 50 Gy, and (3) split-field IMRT with a full-cord block to 50 Gy. Patients were planned using each of these 3 techniques. To facilitate comparison, extended-field plans were normalized to deliver 50 Gy to 95% of the neck volume. Target coverage was assessed using the dose to 95% of the neck volume (D{sub 95}). Mean thyroid and larynx doses were computed. Extended-field IMRT was used as the reference arm; the mean larynx dose was 25.7 ± 7.4 Gy, and the mean thyroid dose was 28.6 ± 2.4 Gy. Split-field IMRT with 2-step blocking reduced laryngeal dose (mean larynx dose 15.2 ± 5.1 Gy) at the cost of a moderate reduction in target coverage (D{sub 95} 41.4 ± 14 Gy) and much higher thyroid dose (mean thyroid dose 44.7 ± 3.7 Gy). Split-field IMRT with initial full-cord block resulted in greater laryngeal sparing (mean larynx dose 14.2 ± 5.1 Gy) and only a moderately higher thyroid dose (mean thyroid dose 31 ± 8 Gy) but resulted in a significant reduction in target coverage (D{sub 95} 34.4 ± 15 Gy). Extended-field IMRT comprehensively covers the low neck and achieves acceptable thyroid and laryngeal sparing. Split-field IMRT with a full-cord block reduces laryngeal doses to less than 20 Gy and spares the thyroid, at the cost of substantially reduced coverage of the low neck. Traditional 2-step split-field IMRT similarly reduces the laryngeal dose but also reduces low-neck coverage and delivers very high doses to the thyroid.

  12. Inhibition of DNA repair by Pentoxifylline and related methylxanthine derivatives

    International Nuclear Information System (INIS)

    Boehm, Lothar; Roos, Wynand Paul; Serafin, Antonio Mendes

    2003-01-01

    The methylxanthine drug Pentoxifylline is reviewed for new properties which have emerged only relatively recently and for which clinical applications can be expected. After a summary on the established systemic effects of Pentoxifylline on the microcirculation and reduction of tumour anoxia, the role of the drug in the treatment of vasoocclusive disorders, cerebral ischemia, infectious diseases, septic shock and acute respiratory distress, the review focuses on another level of drug action which is based on in vitro observations in a variety of cell lines. Pentoxifylline and the related drug Caffeine are known radiosensitizers especially in p53 mutant cells. The explanation that the drug abrogates the G2 block and shortens repair in G2 by promoting early entry into mitosis is not anymore tenable because enhancement of radiotoxicity requires presence of the drug during irradiation and fails when the drug is added after irradiation at the G2 maximum. Repair assays by measurement of recovery ratios and by delayed plating experiments indeed strongly suggested a role in repair which is now confirmed for Pentoxifylline by constant field gel electrophoresis (CFGE) measurements and for Pentoxifylline and for Caffeine by use of a variety of repair mutants. The picture now emerging shows that Caffeine and Pentoxifylline inhibit homologous recombination by targeting members of the PIK kinase family (ATM and ATR) which facilitate repair in G2. Pentoxifylline induced repair inhibition between irradiation dose fractions to counter interfraction repair has been successfully applied in a model for stereotactic surgery. Another realistic avenue of application of Pentoxifylline in tumour therapy comes from experiments which show that repair events in G2 can be targeted directly by addition of cytotoxic drugs and Pentoxifylline at the G2 maximum. Under these conditions massive dose enhancement factors of up to 80 have been observed suggesting that it may be possible to realise

  13. Dose and Dose-Rate Effectiveness Factor (DDREF); Der Dosis- und Dosisleistungs-Effektivitaetsfaktor (DDREF)

    Energy Technology Data Exchange (ETDEWEB)

    Breckow, Joachim [Fachhochschule Giessen-Friedberg, Giessen (Germany). Inst. fuer Medizinische Physik und Strahlenschutz

    2016-08-01

    For practical radiation protection purposes it is supposed that stochastic radiation effects a determined by a proportional dose relation (LNT). Radiobiological and radiation epidemiological studies indicated that in the low dose range a dependence on dose rates might exist. This would trigger an overestimation of radiation risks based on the LNT model. OCRP had recommended a concept to combine all effects in a single factor DDREF (dose and dose-Rate effectiveness factor). There is still too low information on cellular mechanisms of low dose irradiation including possible repair and other processes. The Strahlenschutzkommission cannot identify a sufficient scientific justification for DDREF and recommends an adaption to the actual state of science.

  14. The tissue injury and repair in cancer radiotherapy

    International Nuclear Information System (INIS)

    Matsuzawa, Taiju

    1975-01-01

    One of the difficulties in cancer radiotherapy arises from the fact that the tissue tolerance dose is much smaller than the tumor lethal dose. In our opinion the former depends upon the tolerance of the endothelial cell of the blood vessel in the normal tissue. In this introduction, a new concept regarding the estimation of tissue radiosensitivity was described, and the possible significance of the mode of radiation injury and the repair capability of normal tissue in the cancer radiotheraphy was discussed. (author)

  15. Splitting methods for split feasibility problems with application to Dantzig selectors

    International Nuclear Information System (INIS)

    He, Hongjin; Xu, Hong-Kun

    2017-01-01

    The split feasibility problem (SFP), which refers to the task of finding a point that belongs to a given nonempty, closed and convex set, and whose image under a bounded linear operator belongs to another given nonempty, closed and convex set, has promising applicability in modeling a wide range of inverse problems. Motivated by the increasingly data-driven regularization in the areas of signal/image processing and statistical learning, in this paper, we study the regularized split feasibility problem (RSFP), which provides a unified model for treating many real-world problems. By exploiting the split nature of the RSFP, we shall gainfully employ several efficient splitting methods to solve the model under consideration. A remarkable advantage of our methods lies in their easier subproblems in the sense that the resulting subproblems have closed-form representations or can be efficiently solved up to a high precision. As an interesting application, we apply the proposed algorithms for finding Dantzig selectors, in addition to demonstrating the effectiveness of the splitting methods through some computational results on synthetic and real medical data sets. (paper)

  16. VARIATIONS IN RADIATION SENSITIVITY AND REPAIR AMONG DIFFERENT HEMATOPOIETIC STEM-CELL SUBSETS FOLLOWING FRACTIONATED-IRRADIATION

    NARCIS (Netherlands)

    DOWN, JD; BOUDEWIJN, A; VANOS, R; THAMES, HD; PLOEMACHER, RE

    1995-01-01

    The radiation dose-survival of various hematopoietic cell subsets in murine bone marrow (BM) was determined in the cobblestone area forming cell (CAFC) assay under conditions of single-, split-, and multiple-dose irradiation. A greater recovery in cell survival with decreasing dose per fraction, or

  17. Effect of set up time on sublethal repair in multifield fractionated radiotherapy

    International Nuclear Information System (INIS)

    Kehwar, T.S.; Beriwal, Sushil; Sharma, S.C.

    1998-01-01

    The sublethal repair between two doses given with a variable time interval for mammalian cells in tissue culture was first demonstrated successfully by Elkind and Sutton. Subsequently on the basis of concept of sublethal damage repair between fractions, the radio therapists and radio biologists realized that dose can be increased by increasing the small size fractions. This concept is successfully being used in modern radiotherapy

  18. DNA repair deficiency in neurodegeneration

    DEFF Research Database (Denmark)

    Jeppesen, Dennis Kjølhede; Bohr, Vilhelm A; Stevnsner, Tinna V.

    2011-01-01

    Deficiency in repair of nuclear and mitochondrial DNA damage has been linked to several neurodegenerative disorders. Many recent experimental results indicate that the post-mitotic neurons are particularly prone to accumulation of unrepaired DNA lesions potentially leading to progressive...... neurodegeneration. Nucleotide excision repair is the cellular pathway responsible for removing helix-distorting DNA damage and deficiency in such repair is found in a number of diseases with neurodegenerative phenotypes, including Xeroderma Pigmentosum and Cockayne syndrome. The main pathway for repairing oxidative...... base lesions is base excision repair, and such repair is crucial for neurons given their high rates of oxygen metabolism. Mismatch repair corrects base mispairs generated during replication and evidence indicates that oxidative DNA damage can cause this pathway to expand trinucleotide repeats, thereby...

  19. Repair of single-strand breaks induced in the DNA of Proteus mirabilis by excision repair after UV-irradiation

    International Nuclear Information System (INIS)

    Stoerl, K.; Mund, C.

    1977-01-01

    Single-strand breaks have been produced in the DNA of P. mirabilis after UV-irradiation in dependence on the incident UV-doses. It has been found that there exists a discrepancy between the single-strand breaks estimated from sedimentation in alkaline sucrose gradients and the expected single-strand breaks approximated from measurements of dimer excision. The low number in incision breaks observed by sedimentation experiments is an indication that the cells are able to repair the excision-induced breaks as fast as they are formed. Toluenized cells have been used for investigation of the incision step independently of subsequent repair processes. In presence of NMN the appearance of more single-strand breaks in the DNA has been observed. Furthermore, the number of incision breaks in toluenized cells increased in presence of exogenous ATP. The completion of the excision repair process has been investigated by observing the rejoining of incision breaks. After irradiation with UV-doses higher than approximately 240 erg/mm 2 the number of single-strand breaks remaining unrepaired in the DNA increased. Studies of the influence of nutrition conditions on the repair process have shown approximately the same capacity for repair of single-strand breaks in growth medium as well as in buffer. Progress in the excision repair was also followed by investigation of the DNA synthesized at the template-DNA containing the pyrimidine dimers. In comparison with E. coli, P. mirabilis showed a somewhat lower efficiency for the repair of single-strand breaks during the excision repair. (author)

  20. Handbook of Equipment Repair.

    Science.gov (United States)

    1981-05-14

    state of leapin- fn’rw.rd. Tn recent years, many mechanical repair workers often write and ask us to reprint the book. In our consideration, however...ast 4iron 1. .-eat _--OSIS-RTS 5.5 . . 4-5 t4- cast -3.01 -6 ~.0 ’ ɘ.᝱ 5,,:e j?24 2 * 10- 5 aron C l 50 S lcon : Ielt rSSIS-RQTS-s;.4 u a 2.47 5at- .0

  1. M-Split: A Graphical User Interface to Analyze Multilayered Anisotropy from Shear Wave Splitting

    Science.gov (United States)

    Abgarmi, Bizhan; Ozacar, A. Arda

    2017-04-01

    Shear wave splitting analysis are commonly used to infer deep anisotropic structure. For simple cases, obtained delay times and fast-axis orientations are averaged from reliable results to define anisotropy beneath recording seismic stations. However, splitting parameters show systematic variations with back azimuth in the presence of complex anisotropy and cannot be represented by average time delay and fast axis orientation. Previous researchers had identified anisotropic complexities at different tectonic settings and applied various approaches to model them. Most commonly, such complexities are modeled by using multiple anisotropic layers with priori constraints from geologic data. In this study, a graphical user interface called M-Split is developed to easily process and model multilayered anisotropy with capabilities to properly address the inherited non-uniqueness. M-Split program runs user defined grid searches through the model parameter space for two-layer anisotropy using formulation of Silver and Savage (1994) and creates sensitivity contour plots to locate local maximas and analyze all possible models with parameter tradeoffs. In order to minimize model ambiguity and identify the robust model parameters, various misfit calculation procedures are also developed and embedded to M-Split which can be used depending on the quality of the observations and their back-azimuthal coverage. Case studies carried out to evaluate the reliability of the program using real noisy data and for this purpose stations from two different networks are utilized. First seismic network is the Kandilli Observatory and Earthquake research institute (KOERI) which includes long term running permanent stations and second network comprises seismic stations deployed temporary as part of the "Continental Dynamics-Central Anatolian Tectonics (CD-CAT)" project funded by NSF. It is also worth to note that M-Split is designed as open source program which can be modified by users for

  2. The split-sting trait in Apis mellifera induced by cobalt 60 gamma radiation

    International Nuclear Information System (INIS)

    Silva, Vera Lucia Maciel

    1993-01-01

    The Split-Sting (SS) trait in honey bees, induced by gamma radiation, was discovered by Soares (1975). Bees with this trait are unable to sting, because the parts that compose the sting are separated. Many studies have been done in order to understand this new mutation. We studied the effect of gamma radiation on induction of the SS trait in feral bee strains. The doses were applied to the phase of larvae of queens with 5 days old. The following results were obtained: all doses of radiation induced the SS trait. There was an increase in the percentage of queens with SS with an increase in radiation dose; the SS trait induced by radiation is probably phenocopy; SS bees were observed in nature; increase of the rate mortality and malformation with an increase in radiation dose. (author)

  3. Remotely controlled repairs at Douglas Point NGS

    International Nuclear Information System (INIS)

    Broad, Les

    In September, 1977, leakage of heavy water at a rate of 125 kg/hr was detected in an area of the Douglas Point NGS reactor vault below the calandria known as the lower labyrinth. Radiation in the area ranges up to 5000 R/hr and the only ready access was through four 75 mm inspection ports that open into the moderator room. Remote-controlled equipment was designed and built to diagnose the problems and carry out repairs. All damaged piping was fixed, supports were replaced as needed, and system vibration was reduced. The work was done with no injuries and little radiation dose

  4. Early discharge after external anal sphincter repair

    DEFF Research Database (Denmark)

    Rosenberg, J; Kehlet, H

    1999-01-01

    and complications within 30 days after the operation. Surgery was performed during the period of March 1993 to May 1997. The accelerated-stay program included preoperative information, no premedication, a surgical procedure without colostomy, single-dose prophylactic antibiotics, paracetamol for analgesia, free...... surgery and 5 patients stayed for 48 hours after the operation. There was no 30-day morbidity, and no patient received a colostomy in conjunction with the sphincter repair. Fourteen of 19 patients available for follow-up reported a significantly improved functional result compared with preoperative state...

  5. Effect of hyperthermia on radiation damage and its repair in Tribolium confusum

    International Nuclear Information System (INIS)

    Lai, P.K.

    1977-01-01

    A series of temperature tolerance curves from 43.5 0 C to 46.0 0 C in 0.5 0 C increment were determined. Two non-lethal hyperthermia schemes, i.e., 45.0 0 C for 2 hr and 43.0 0 C for 2 hr were chosen to examine the sensitizing effect of heat on lethality produced by radiation in flour beetles. When hyperthermia was applied either immediately before or after irradiation, the sensitizing effect of hyperthermia was indicated by the shifting of the regression line of survival in probits on dose to the left of that of the control. The sensitizing effect as measured by decreased LD 50 did not reveal any definite trend related to the order of application of the two modalities in immediate sequence. The effect of hyperthermia was more dramatic in dose-fractionation experiments. Flour beetles exhibited typical Elkind kinetics of split-dose repair and recovery, and the amount of the sparing effect of dose-fractionation (sdf) was influenced by interfraction temperature. Both interfraction hypothermia (i.e., less than or equal to 10 0 C) and interfraction hyperthermia (i.e., > 42.0 0 C) completely suppress sdf. However, the mechanism involved in the suppression of sdf by hypothermia was different than that by hyperthermia. In the former, the suppression of sdf was reversible immediately upon return to the normal incubation temperature of 30 0 C; in the latter, the suppression of sdf was protracted and the reversibility of sdf depended on the severity of the hyperthermia treatment. Hyperthermia of 43.0 0 C for 2 hr, applied either immediately before or after the first radiation dose, suppressed sdf for 6-10 hr, and then sdf reappeared slowly, so that the final level of survival was slightly less than that of the comparable groups maintained at 30 0 C. With the more severe hyperthermia treatment of 45.0 0 C for 2 hr, sdf was suppressed for almost 36 hr after return to 30 0 C although there were some slight surges in survival

  6. Relationship between mandibular anatomy and the occurrence of a bad split upon sagittal split osteotomy.

    Science.gov (United States)

    Aarabi, Mohammadali; Tabrizi, Reza; Hekmat, Mina; Shahidi, Shoaleh; Puzesh, Ayatollah

    2014-12-01

    A bad split is a troublesome complication of the sagittal split osteotomy (SSO). The aim of this study was to evaluate the relation between the occurrence of a bad split and mandibular anatomy in SSO using cone-beam computed tomography. The authors designed a cohort retrospective study. Forty-eight patients (96 SSO sites) were studied. The buccolingual thickness of the retromandibular area (BLR), the buccolingual thickness of the ramus at the level of the lingula (BLTR), the height of the mandible from the alveolar crest to the inferior border of the mandible, (ACIB), the distance between the sigmoid notch and the inferior border of the mandible (SIBM), and the anteroposterior width of the ramus (APWR) were measured. The independent t test was applied to compare anatomic measurements between the group with and the group without bad splits. The receiver operating characteristic (ROC) test was used to find a cutoff point in anatomic size for various parts of the mandible related to the occurrence of bad splits. The mean SIBM was 47.05±6.33 mm in group 1 (with bad splits) versus 40.66±2.44 mm in group 2 (without bad splits; P=.01). The mean BLTR was 5.74±1.11 mm in group 1 versus 3.19±0.55 mm in group 2 (P=.04). The mean BLR was 14.98±2.78 mm in group 1 versus 11.21±1.29 mm in group 2 (P=.001). No statistically significant difference was found for APWR and ACIB between the 2 groups. The ROC test showed cutoff points of 10.17 mm for BLR, 36.69 mm for SIBM, and 4.06 mm for BLTR. This study showed that certain mandibular anatomic differences can increase the risk of a bad split during SSO surgery. Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  7. Method of orthogonally splitting imaging pose measurement

    Science.gov (United States)

    Zhao, Na; Sun, Changku; Wang, Peng; Yang, Qian; Liu, Xintong

    2018-01-01

    In order to meet the aviation's and machinery manufacturing's pose measurement need of high precision, fast speed and wide measurement range, and to resolve the contradiction between measurement range and resolution of vision sensor, this paper proposes an orthogonally splitting imaging pose measurement method. This paper designs and realizes an orthogonally splitting imaging vision sensor and establishes a pose measurement system. The vision sensor consists of one imaging lens, a beam splitter prism, cylindrical lenses and dual linear CCD. Dual linear CCD respectively acquire one dimensional image coordinate data of the target point, and two data can restore the two dimensional image coordinates of the target point. According to the characteristics of imaging system, this paper establishes the nonlinear distortion model to correct distortion. Based on cross ratio invariability, polynomial equation is established and solved by the least square fitting method. After completing distortion correction, this paper establishes the measurement mathematical model of vision sensor, and determines intrinsic parameters to calibrate. An array of feature points for calibration is built by placing a planar target in any different positions for a few times. An terative optimization method is presented to solve the parameters of model. The experimental results show that the field angle is 52 °, the focus distance is 27.40 mm, image resolution is 5185×5117 pixels, displacement measurement error is less than 0.1mm, and rotation angle measurement error is less than 0.15°. The method of orthogonally splitting imaging pose measurement can satisfy the pose measurement requirement of high precision, fast speed and wide measurement range.

  8. Heat transfer with a split water channel

    International Nuclear Information System (INIS)

    Krinsky, S.

    1978-01-01

    The heat transfer problem associated with the incidence of synchrotron radiation upon a vacuum chamber wall cooled by a single water channel was previously studied, and a numerical solution to the potential problem was found using the two-dimensional magnet program POISSON. Calculations were extended to consider the case of a split water channel using POISSON to solve the potential problem for a given choice of parameters. By optimizing the dimensions, boiling of the water can be avoided. A copper chamber is a viable solution to the heat transfer problem at a beam port

  9. Joining-Splitting Interaction of Noncritical String

    Science.gov (United States)

    Hadasz, Leszek; Jaskólski, Zbigniew

    The joining-splitting interaction of noncritical bosonic string is analyzed in the light-cone formulation. The Mandelstam method of constructing tree string amplitudes is extended to the bosonic massive string models of the discrete series. The general properties of the Liouville longitudinal excitations which are necessary and sufficient for the Lorentz covariance of the light-cone amplitudes are derived. The results suggest that the covariant and the light-cone approach are equivalent also in the noncritical dimensions. Some aspects of unitarity of interacting noncritical massive string theory are discussed.

  10. Permutation 2-groups I: structure and splitness

    OpenAIRE

    Elgueta, Josep

    2013-01-01

    By a 2-group we mean a groupoid equipped with a weakened group structure. It is called split when it is equivalent to the semidirect product of a discrete 2-group and a one-object 2-group. By a permutation 2-group we mean the 2-group $\\mathbb{S}ym(\\mathcal{G})$ of self-equivalences of a groupoid $\\mathcal{G}$ and natural isomorphisms between them, with the product given by composition of self-equivalences. These generalize the symmetric groups $\\mathsf{S}_n$, $n\\geq 1$, obtained when $\\mathca...

  11. Random tree growth by vertex splitting

    International Nuclear Information System (INIS)

    David, F; Dukes, W M B; Jonsson, T; Stefánsson, S Ö

    2009-01-01

    We study a model of growing planar tree graphs where in each time step we separate the tree into two components by splitting a vertex and then connect the two pieces by inserting a new link between the daughter vertices. This model generalizes the preferential attachment model and Ford's α-model for phylogenetic trees. We develop a mean field theory for the vertex degree distribution, prove that the mean field theory is exact in some special cases and check that it agrees with numerical simulations in general. We calculate various correlation functions and show that the intrinsic Hausdorff dimension can vary from 1 to ∞, depending on the parameters of the model

  12. Split coaxial RFQ structure with modulated vanes

    International Nuclear Information System (INIS)

    Arai, S.

    1983-10-01

    A new split coaxial RFO structure with modulated vanes is proposed. The structure is designed to accelerate 238 U 4+ from 1.68 keV/u to 45.1 keV/u at frequency of 12.5 MHz. The cavity is 1.6 m in diameter and 8 m in length. The cavity consists of four cavity modules divided by three stems which support horizontal and vertical vanes periodically and alternatively. At the same time, problems on the beam dynamics and design procedures are described and discussed. (orig.)

  13. Sunspot splitting triggering an eruptive flare

    Science.gov (United States)

    Louis, Rohan E.; Puschmann, Klaus G.; Kliem, Bernhard; Balthasar, Horst; Denker, Carsten

    2014-02-01

    Aims: We investigate how the splitting of the leading sunspot and associated flux emergence and cancellation in active region NOAA 11515 caused an eruptive M5.6 flare on 2012 July 2. Methods: Continuum intensity, line-of-sight magnetogram, and dopplergram data of the Helioseismic and Magnetic Imager were employed to analyse the photospheric evolution. Filtergrams in Hα and He I 10830 Å of the Chromospheric Telescope at the Observatorio del Teide, Tenerife, track the evolution of the flare. The corresponding coronal conditions were derived from 171 Å and 304 Å images of the Atmospheric Imaging Assembly. Local correlation tracking was utilized to determine shear flows. Results: Emerging flux formed a neutral line ahead of the leading sunspot and new satellite spots. The sunspot splitting caused a long-lasting flow towards this neutral line, where a filament formed. Further flux emergence, partly of mixed polarity, as well as episodes of flux cancellation occurred repeatedly at the neutral line. Following a nearby C-class precursor flare with signs of interaction with the filament, the filament erupted nearly simultaneously with the onset of the M5.6 flare and evolved into a coronal mass ejection. The sunspot stretched without forming a light bridge, splitting unusually fast (within about a day, complete ≈6 h after the eruption) in two nearly equal parts. The front part separated strongly from the active region to approach the neighbouring active region where all its coronal magnetic connections were rooted. It also rotated rapidly (by 4.9° h-1) and caused significant shear flows at its edge. Conclusions: The eruption resulted from a complex sequence of processes in the (sub-)photosphere and corona. The persistent flows towards the neutral line likely caused the formation of a flux rope that held the filament. These flows, their associated flux cancellation, the emerging flux, and the precursor flare all contributed to the destabilization of the flux rope. We

  14. Injuries caused by firewood splitting machines.

    Science.gov (United States)

    Hellstrand, P H

    1989-01-01

    The aim of this paper is to present the types of injury caused by firewood splitting machines and also to elucidate the accident mechanism. The study is based on 15 cases. The machine has a rotating spiral cone, and usually the victims' gloved fingertips were caught by the point of the cone. This led to either amputations, usually of radial fingers and/or penetrating wounds through the middle of the hand. In most cases the accidents could not be blamed on bad working techniques. The study of the mechanisms of injury points to insufficient protective devices in a machine construction which has a potentially dangerous working principle.

  15. Electric Dipole Moments in Split Supersymmetry

    CERN Document Server

    Giudice, Gian Francesco

    2006-01-01

    We perform a quantitative study of the neutron and electron electric dipole moments (EDM) in Supersymmetry, in the limit of heavy scalars. The leading contributions arise at two loops. We give the complete analytic result, including a new contribution associated with Z-Higgs exchange, which plays an important and often leading role in the neutron EDM. The predictions for the EDM are typically within the sensitivities of the next generation experiments. We also analyse the correlation between the electron and neutron EDM, which provides a robust test of Split Supersymmetry.

  16. Multiparty hierarchical quantum-information splitting

    International Nuclear Information System (INIS)

    Wang Xinwen; Zhang Dengyu; Tang Shiqing; Xie Lijun

    2011-01-01

    We propose a scheme for multiparty hierarchical quantum-information splitting (QIS) with a multipartite entangled state, where a boss distributes a secret quantum state to two grades of agents asymmetrically. The agents who belong to different grades have different authorities for recovering the boss's secret. Except for the boss's Bell-state measurement, no nonlocal operation is involved. The presented scheme is also shown to be secure against eavesdropping. Such a hierarchical QIS is expected to find useful applications in the field of modern multipartite quantum cryptography.

  17. Yield and nutritional efficiency of corn in response to rates and splits of nitrogen fertilization

    Directory of Open Access Journals (Sweden)

    Telmo Jorge Carneiro Amado

    Full Text Available ABSTRACT Despite its relevance, nitrogen is poorly utilized by the plants when improperly applied. Thus, the objective of this study was to evaluate the yield and nitrogen use efficiency (NUE in corn in response to doses and split application of nitrogen fertilization. The experimental design was a randomized block design, with three replications. Doses of nitrogen of 0, 30, 60 and 180 kg ha-1 were applied at sowing in order to create different nutritional status of corn plants and to obtain different values of Normalized Difference Vegetation Index (NDVI measured with “Greenseeker®” optical sensor. The subplots with nitrogen doses in topdressing of 0, 30, 60 and 90 kg ha-1 at V8 and a dose of 60 kg ha-1 at V12 were placed in experimental plots with doses of 0, 30, 60 and 180 kg ha-1 of nitrogen at sowing. Moreover, NUE was calculated in the experiment using agronomic indexes determined by applications of nitrogen in late topdressing (V8 and V12 and contrasted to the possible combinations at doses of 60, 90 and 120 kg ha-1 of total N applied. The results showed the occurrence of a linear relationship between nitrogen fertilizer dose and NDVI at V8 as well as at V12 stages. Late topdressing fertilizations (V12 did not cause a decrease in grain yield when combined with nitrogen fertilization at sowing, moreover resulted in higher NUE. Split the nitrogen dose showed better NUE than the combinations where nitrogen was not applied at sowing or in topdressing. The delay of nitrogen topdressing can be an alternative for the planning of the moment of the N fertilization according to the climate forecast in each region.

  18. Repair of lesions provoked by X-rays in embryos of Drosophila (D. melanogaster Meig)

    International Nuclear Information System (INIS)

    Ghelelovitch, S.

    1975-01-01

    The sensitivity of Drosophila eggs to the lethal action of X-rays did not remain constant during embryogenesis. The X-ray doses used in the present investigation may have retarded the hatching of the larvae but did not block development immediately after irradiation. A fraction of the damage induced in young embryos was repaired during gastrulation. The amount of repair was independent of the X-ray dose but was influenced by the temperature. The damage could be repaired even after the cells of the embryo had undergone many mitotic cycles. (author)

  19. Genotoxic thresholds, DNA repair, and susceptibility in human populations

    International Nuclear Information System (INIS)

    Jenkins, Gareth J.S.; Zair, Zoulikha; Johnson, George E.; Doak, Shareen H.

    2010-01-01

    It has been long assumed that DNA damage is induced in a linear manner with respect to the dose of a direct acting genotoxin. Thus, it is implied that direct acting genotoxic agents induce DNA damage at even the lowest of concentrations and that no 'safe' dose range exists. The linear (non-threshold) paradigm has led to the one-hit model being developed. This 'one hit' scenario can be interpreted such that a single DNA damaging event in a cell has the capability to induce a single point mutation in that cell which could (if positioned in a key growth controlling gene) lead to increased proliferation, leading ultimately to the formation of a tumour. There are many groups (including our own) who, for a decade or more, have argued, that low dose exposures to direct acting genotoxins may be tolerated by cells through homeostatic mechanisms such as DNA repair. This argument stems from the existence of evolutionary adaptive mechanisms that allow organisms to adapt to low levels of exogenous sources of genotoxins. We have been particularly interested in the genotoxic effects of known mutagens at low dose exposures in human cells and have identified for the first time, in vitro genotoxic thresholds for several mutagenic alkylating agents (Doak et al., 2007). Our working hypothesis is that DNA repair is primarily responsible for these thresholded effects at low doses by removing low levels of DNA damage but becoming saturated at higher doses. We are currently assessing the roles of base excision repair (BER) and methylguanine-DNA methyltransferase (MGMT) for roles in the identified thresholds (Doak et al., 2008). This research area is currently important as it assesses whether 'safe' exposure levels to mutagenic chemicals can exist and allows risk assessment using appropriate safety factors to define such exposure levels. Given human variation, the mechanistic basis for genotoxic thresholds (e.g. DNA repair) has to be well defined in order that susceptible individuals are

  20. [Biomarkers of radiation-induced DNA repair processes].

    Science.gov (United States)

    Vallard, Alexis; Rancoule, Chloé; Guy, Jean-Baptiste; Espenel, Sophie; Sauvaigo, Sylvie; Rodriguez-Lafrasse, Claire; Magné, Nicolas

    2017-11-01

    The identification of DNA repair biomarkers is of paramount importance. Indeed, it is the first step in the process of modulating radiosensitivity and radioresistance. Unlike tools of detection and measurement of DNA damage, DNA repair biomarkers highlight the variations of DNA damage responses, depending on the dose and the dose rate. The aim of the present review is to describe the main biomarkers of radiation-induced DNA repair. We will focus on double strand breaks (DSB), because of their major role in radiation-induced cell death. The most important DNA repair biomarkers are DNA damage signaling proteins, with ATM, DNA-PKcs, 53BP1 and γ-H2AX. They can be analyzed either using immunostaining, or using lived cell imaging. However, to date, these techniques are still time and money consuming. The development of "omics" technologies should lead the way to new (and usable in daily routine) DNA repair biomarkers. Copyright © 2017 Société Française du Cancer. Published by Elsevier Masson SAS. All rights reserved.

  1. Improving Aviation Depot Level Repairable (AVDLR) Inventory and Repair Management

    National Research Council Canada - National Science Library

    Baird, Dennis

    1997-01-01

    .... Additionally, research was conducted to document the management process for determining repair requirements at the Naval Inventory Control Point Philadelphia and how those requirements are accepted...

  2. Splitting of the Pygmy Dipole Resonance

    International Nuclear Information System (INIS)

    Endres, J.; Zilges, A.; Butler, P.; Herzberg, R.-D.; Scheck, M.; Harakeh, M. N.; Harissopulos, S.; Lagoyannis, A.; Kruecken, R.; Ring, P.; Litvinova, E.; Pietralla, N.; Ponomarev, V. Yu.; Sonnabend, K.; Popescu, L.; Savran, D.; Stoica, V. I.; Woertche, H. J.

    2011-01-01

    In recent years investigations have been made to study the electric Pygmy Dipole Resonance (PDR) systematically, mainly in semi-magic nuclei. For this purpose the well understood high resolution (γ,γ') photon scattering method is used. In complementary (α,α'γ) coincidence experiments at E α = 136 MeV a similar γ-energy resolution and a high selectivity to E1 transitions can be obtained at the Big-Bite Spectrometer (BBS) at KVI, Groningen. In comparison to the (γ,γ') method a structural splitting of the PDR is observed in the N = 82 nuclei 138 Ba and 140 Ce and in the Z = 50 nucleus 124 Sn. The low energy part is excited in (γ,γ') as well as in (α,α'γ) while the high energy part is observed in (γ,γ') only. The experimental results together with theoretical QPM and RQTBA calculations on 124 Sn which are able to reproduce the splitting of the PDR qualitatively are presented. The low-lying group of J π = 1 - states seem to represent the more isoscalar neutron-skin oscillation of the PDR while the energetically higher-lying states seemingly belong to the transitional region between the PDR and the isovector Giant Dipole Resonance (IVGDR).

  3. Splitting of the weak hypercharge quantum

    Science.gov (United States)

    Nielsen, H. B.; Brene, N.

    1991-08-01

    The ratio between the weak hypercharge quantum for particles having no coupling to the gauge bosons corresponding to the semi-simple component of the gauge group and the smallest hypercharge quantum for particles that do have such couplings is exceptionally large for the standard model, considering its rank. To compare groups with respect to this property we propose a quantity χ which depends on the rank of the group and the splitting ratio of the hypercharge(s) to be found in the group. The quantity χ has maximal value for the gauge group of the standard model. This suggests that the hypercharge splitting may play an important rôle either in the origin of the gauge symmetry at a fundamental scale or in some kind of selection mechanism at a scale perhaps nearer to the experimental scale. Such a selection mechanism might be what we have called confusion which removes groups with many (so-called generalized) automorphisms. The quantity χ tends to be large for groups with few generalized automorphisms.

  4. Splitting of the weak hypercharge quantum

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, H.B.; Brene, N. (Niels Bohr Inst., Copenhagen (Denmark))

    1991-08-05

    The ratio between the weak hypercharge quantum for particles having no coupling to the gauge bosons corresponding to the semi-simple component of the gauge group and the smallest hypercharge quantum for particles that do have such couplings is exceptionally large for the standard model, considering its rank. To compare groups with respect to this property we propose a quantity {chi} which depends on the rank of the group and the splitting ratio of the hypercharge(s) to be found in the group. The quantity {chi} has maximal value for the gauge group of the standard model. This suggests that the hypercharge splitting may play an important role either in the origin of the gauge symmetry at a fundamental scale or in some kind of selection mechanism at a scale perhaps nearer to the experimental scale. Such a selection mechanism might be what we have called confusion which removes groups with many (so-called generalized) automorphisms. The quantity {chi} tends to be large for groups with few generalized automorphisms. (orig.).

  5. Dynamics of a split torque helicopter transmission

    Science.gov (United States)

    Krantz, Timothy L.

    1994-06-01

    Split torque designs, proposed as alternatives to traditional planetary designs for helicopter main rotor transmissions, can save weight and be more reliable than traditional designs. This report presents the results of an analytical study of the system dynamics and performance of a split torque gearbox that uses a balance beam mechanism for load sharing. The Lagrange method was applied to develop a system of equations of motion. The mathematical model includes time-varying gear mesh stiffness, friction, and manufacturing errors. Cornell's method for calculating the stiffness of spur gear teeth was extended and applied to helical gears. The phenomenon of sidebands spaced at shaft frequencies about gear mesh fundamental frequencies was simulated by modeling total composite gear errors as sinusoid functions. Although the gearbox has symmetric geometry, the loads and motions of the two power paths differ. Friction must be considered to properly evaluate the balance beam mechanism. For the design studied, the balance beam is not an effective device for load sharing unless the coefficient of friction is less than 0.003. The complete system stiffness as represented by the stiffness matrix used in this analysis must be considered to precisely determine the optimal tooth indexing position.

  6. Strong CP, flavor, and twisted split fermions

    International Nuclear Information System (INIS)

    Harnik, Roni; Perez, Gilad; Schwartz, Matthew D.; Shirman, Yuri

    2005-01-01

    We present a natural solution to the strong CP problem in the context of split fermions. By assuming CP is spontaneously broken in the bulk, a weak CKM phase is created in the standard model due to a twisting in flavor space of the bulk fermion wavefunctions. But the strong CP phase remains zero, being essentially protected by parity in the bulk and CP on the branes. As always in models of spontaneous CP breaking, radiative corrections to theta bar from the standard model are tiny, but even higher dimension operators are not that dangerous. The twisting phenomenon was recently shown to be generic, and not to interfere with the way that split fermions naturally weaves small numbers into the standard model. It follows that out approach to strong CP is compatible with flavor, and we sketch a comprehensive model. We also look at deconstructed version of this setup which provides a viable 4D model of spontaneous CP breaking which is not in the Nelson-Barr class. (author)

  7. Zeeman splitting of surface-scattered neutrons

    International Nuclear Information System (INIS)

    Felcher, G.P.; Adenwalla, S.; De Haan, V.O.; Van Well, A.A.

    1995-01-01

    If a beam of slow neutrons impinges on a solid at grazing incidence, the neutrons reflected can be used to probe the composition and magnetization of the solid near its surface. In this process, the incident and reflected neutrons generally have identical kinetic energies. Here we report the results of an experiment in which subtle inelastic scattering processes are revealed as relatively large deviations in scattering angle. The neutrons are scattered from a ferromagnetic surface in the presence of a strong ambient magnetic field, and exhibit a small but significant variation in kinetic energy as a function of the reflection angle. This effect is attributable to the Zeeman splitting of the energies of the neutron spin states due to the ambient magnetic field: some neutrons flip their spins upon reflection from the magnetized surface, thereby exchanging kinetic energy for magnetic potential energy. The subtle effects of Zeeman splitting are amplified by the extreme sensitivity of grazing-angle neutron scattering, and might also provide a useful spectroscopic tool if significant practical obstacles (such as low interaction cross-sections) can be overcome. (author)

  8. A study on Sorghum bicolor (L. Moench response to split application of herbicides

    Directory of Open Access Journals (Sweden)

    Kaczmarek Sylwia

    2017-06-01

    Full Text Available Field experiments to evaluate the split application of mesotrione + s-metolachlor, mesotrione + terbuthylazine, dicamba + prosulfuron, terbuthylazine + mesotrione + s-metolachlor, and sulcotrione in the cultivation of sorghum var. Rona 1 were carried out in 2012 and 2013. The field tests were conducted at the field experimental station in Winna Góra, Poznań, Poland. Treatments with the herbicides were performed directly after sowing (PE and at leaf stage 1–2 (AE1 or at leaf stage 3–4 (AE2 of sorghum. The treatments were carried out in a laid randomized block design with 4 replications. The results showed that the tested herbicides applied at split doses were effective in weed control. After the herbicide application weed density and weed biomass were significantly reduced compared to the infested control. The best results were achieved after the application of mesotrione tank mixture with s-metolachlor and terbuthylazine. Application of split doses of herbicides was also correlated with the density, biomass, and height of sorghum.

  9. When is cartilage repair successful?

    International Nuclear Information System (INIS)

    Raudner, M.; Roehrich, S.; Zalaudek, M.; Trattnig, S.; Schreiner, M.M.

    2017-01-01

    Focal cartilage lesions are a cause of long-term disability and morbidity. After cartilage repair, it is crucial to evaluate long-term progression or failure in a reproducible, standardized manner. This article provides an overview of the different cartilage repair procedures and important characteristics to look for in cartilage repair imaging. Specifics and pitfalls are pointed out alongside general aspects. After successful cartilage repair, a complete, but not hypertrophic filling of the defect is the primary criterion of treatment success. The repair tissue should also be completely integrated to the surrounding native cartilage. After some months, the transplants signal should be isointense compared to native cartilage. Complications like osteophytes, subchondral defects, cysts, adhesion and chronic bone marrow edema or joint effusion are common and have to be observed via follow-up. Radiological evaluation and interpretation of postoperative changes should always take the repair method into account. (orig.) [de

  10. Effect of fibrin glue derived from snake venom on the viability of autogenous split-thickness skin graft

    Directory of Open Access Journals (Sweden)

    S.C. Rahal

    2004-01-01

    Full Text Available The aim of this study was to analyze the effect of snake venom derived from fibrin glue on the viability of split-thickness skin graft. Nine crossbreed dogs were used. Full-thickness skin segments measuring 4 x 4 cm were bilaterally excised from the proximal radial area on each dog. A split-thickness skin graft was harvestedfrom left lateral thoracic area using a freehand graft knife, and was secured to the left recipient bed using several simple interrupted sutures of 3-0 nylon (sutured graft. A split-thickness skin graft was harvested from the right lateral thoracic area using a graft knife. Fibrin glue derived from snake venom was applied to the recipient bed, and 8 equidistant simple interrupted sutures of 3-0 nylon were used to secure the skin graft (glued graft. Viable and nonviable areas were traced on a transparent sheet and measured using a Nikon Photomicroscope connected to a KS-300 image analysis system. The skin graft and recipient bed were collected from three dogs at day 7, 15, and 30 postoperative. The glued grafts had statistically higher graft viability than sutured grafts. Histological examination showed that the tissue repair process in the glued grafts was more accentuated than sutured grafts. It was possible to conclude that fibrin glue derived from snake venom increased survival of autogenous split-thickness skin graft.

  11. Application of split field technique with 42 MeV betatron bremsstrahlung

    Energy Technology Data Exchange (ETDEWEB)

    Spurny, V; Caha, A; Krystof, V; Ott, O [Vyzkumny Ustav Klinicke a Experimentalni Onkologie, Brno (Czechoslovakia)

    1977-03-01

    The split field technique of external irradiation in oncology is described. A 120x28x79 mm lead shielding block was manufactured for a bremsstrahlung radiation with 42 MeV maximum energy. The block was secured to a holder whose design corresponded to tube holders. The block shielding capacity was tested by phantom measurements at a focal depth of 130 mm and at a distance of the block from the phantom surface of 990 mm. For the 42 MeV bremsstrahlung the reduction was found to be 15% of the focal dose in the 20x20 cm/sup 2/ field in the focal depth at a distance of 1200 mm from the bremsstrahlung focus. Dose distribution was established by using two opposite fields in combination as well as by the courses of the maximum and the relative doses in variation with the female patient's antero-posterior diameter. The results show that the split field technique permits a short adjustment time, is simple and reproducible. As against cobalt application, the beam characteristics permit reducing the integral dose.

  12. Frequency of intrachromosomal homologous recombination induced by UV radiation in normally repairing and excision repair-deficient human cells

    International Nuclear Information System (INIS)

    Tsujimura, T.; Maher, V.M.; McCormick, J.J.; Godwin, A.R.; Liskay, R.M.

    1990-01-01

    To investigate the role of DNA damage and nucleotide excision repair in intrachromosomal homologous recombination, a plasmid containing duplicated copies of the gene coding for hygromycin resistance was introduced into the genome of a repair-proficient human cell line, KMST-6, and two repair-deficient lines, XP2OS(SV) from xeroderma pigmentosum complementation group A and XP2YO(SV) from complementation group F. Neither hygromycin-resistance gene codes for a functional enzyme because each contains an insertion/deletion mutation at a unique site, but recombination between the two defective genes can yield hygromycin-resistant cells. The rates of spontaneous recombination in normal and xeroderma pigmentosum cell strains containing the recombination substrate were found to be similar. The frequency of UV-induced recombination was determined for three of these cell strains. At low doses, the group A cell strain and the group F cell strain showed a significant increase in frequency of recombinants. The repair-proficient cell strain required 10-to 20-fold higher doses of UV to exhibit comparable increases in frequency of recombinants. These results suggest that unexcised DNA damage, rather than the excision repair process per se, stimulates such recombination

  13. Inducible DNA-repair systems in yeast: competition for lesions.

    Science.gov (United States)

    Mitchel, R E; Morrison, D P

    1987-03-01

    DNA lesions may be recognized and repaired by more than one DNA-repair process. If two repair systems with different error frequencies have overlapping lesion specificity and one or both is inducible, the resulting variable competition for the lesions can change the biological consequences of these lesions. This concept was demonstrated by observing mutation in yeast cells (Saccharomyces cerevisiae) exposed to combinations of mutagens under conditions which influenced the induction of error-free recombinational repair or error-prone repair. Total mutation frequency was reduced in a manner proportional to the dose of 60Co-gamma- or 254 nm UV radiation delivered prior to or subsequent to an MNNG exposure. Suppression was greater per unit radiation dose in cells gamma-irradiated in O2 as compared to N2. A rad3 (excision-repair) mutant gave results similar to wild-type but mutation in a rad52 (rec-) mutant exposed to MNNG was not suppressed by radiation. Protein-synthesis inhibition with heat shock or cycloheximide indicated that it was the mutation due to MNNG and not that due to radiation which had changed. These results indicate that MNNG lesions are recognized by both the recombinational repair system and the inducible error-prone system, but that gamma-radiation induction of error-free recombinational repair resulted in increased competition for the lesions, thereby reducing mutation. Similarly, gamma-radiation exposure resulted in a radiation dose-dependent reduction in mutation due to MNU, EMS, ENU and 8-MOP + UVA, but no reduction in mutation due to MMS. These results suggest that the number of mutational MMS lesions recognizable by the recombinational repair system must be very small relative to those produced by the other agents. MNNG induction of the inducible error-prone systems however, did not alter mutation frequencies due to ENU or MMS exposure but, in contrast to radiation, increased the mutagenic effectiveness of EMS. These experiments demonstrate

  14. Engineered Heart Repair.

    Science.gov (United States)

    Fujita, B; Zimmermann, W-H

    2017-08-01

    There is a pressing need for the development of advanced heart failure therapeutics. Current state-of-the-art is protection from neurohumoral overstimulation, which fails to address the underlying cause of heart failure, namely loss of cardiomyocytes. Implantation of stem cell-derived cardiomyocytes via tissue-engineered myocardium is being advanced to realize the remuscularization of the failing heart. Here, we discuss pharmacological challenges pertaining to the clinical translation of tissue-engineered heart repair with a focus on engineered heart muscle (EHM). © 2017 American Society for Clinical Pharmacology and Therapeutics.

  15. Influence of postoperative low-level laser therapy on the osseointegration of self-tapping implants in the posterior maxilla: A 6-week split-mouth clinical study

    OpenAIRE

    Mandić Borka; Lazić Zoran; Marković Aleksa; Mandić Bojan; Mandić Miška; Đinić Ana; Miličić Biljana

    2015-01-01

    Background/Aim. Low-level laser therapy (LLLT) has been proven to stimulate bone repair, affecting cellular proliferation, differentiation and adhesion, and has shown a potential to reduce the healing time following implant placement. The aim of this clinical study was to investigate the influence of postoperative LLLT osseointegration and early success of self-tapping implants placed into low-density bone. Methods. Following the split-mouth design, self-ta...

  16. Numerical simulation and experiment on multilayer stagger-split die.

    Science.gov (United States)

    Liu, Zhiwei; Li, Mingzhe; Han, Qigang; Yang, Yunfei; Wang, Bolong; Sui, Zhou

    2013-05-01

    A novel ultra-high pressure device, multilayer stagger-split die, has been constructed based on the principle of "dividing dies before cracking." Multilayer stagger-split die includes an encircling ring and multilayer assemblages, and the mating surfaces of the multilayer assemblages are mutually staggered between adjacent layers. In this paper, we investigated the stressing features of this structure through finite element techniques, and the results were compared with those of the belt type die and single split die. The contrast experiments were also carried out to test the bearing pressure performance of multilayer stagger-split die. It is concluded that the stress distributions are reasonable and the materials are utilized effectively for multilayer stagger-split die. And experiments indicate that the multilayer stagger-split die can bear the greatest pressure.

  17. Quantitative analysis on electric dipole energy in Rashba band splitting.

    Science.gov (United States)

    Hong, Jisook; Rhim, Jun-Won; Kim, Changyoung; Ryong Park, Seung; Hoon Shim, Ji

    2015-09-01

    We report on quantitative comparison between the electric dipole energy and the Rashba band splitting in model systems of Bi and Sb triangular monolayers under a perpendicular electric field. We used both first-principles and tight binding calculations on p-orbitals with spin-orbit coupling. First-principles calculation shows Rashba band splitting in both systems. It also shows asymmetric charge distributions in the Rashba split bands which are induced by the orbital angular momentum. We calculated the electric dipole energies from coupling of the asymmetric charge distribution and external electric field, and compared it to the Rashba splitting. Remarkably, the total split energy is found to come mostly from the difference in the electric dipole energy for both Bi and Sb systems. A perturbative approach for long wave length limit starting from tight binding calculation also supports that the Rashba band splitting originates mostly from the electric dipole energy difference in the strong atomic spin-orbit coupling regime.

  18. Relationship of DNA repair and chromosome aberrations to potentially lethal damage repair in X-irradiated mammalian cells

    International Nuclear Information System (INIS)

    Fornace, A.J. Jr.; Nagasawa, H.; Little, J.B.

    1980-01-01

    By the alkaline elution technique, the repair of x-ray-induced DNA single strand breaks and DNA-protein cross-links was investigated in stationary phase, contact-inhibited mouse cells. During the first hour of repair, approximately 90% of x-ray induced single strand breaks were rejoined whereas most of the remaining breaks were rejoined more slowly during the next 5 h. The number of residual non-rejoined single strand breaks was approximately proportional to the x-ray dose at early repair times. DNA-protein cross-links were removed at a slower rate - T 1/2 approximately 10 to 12 h. Cells were subcultured at low density at various times after irradiation and scored for colony survival, and chromosome aberrations in the first mitosis after sub-culture. Both cell lethality and the frequency of chromosome aberrations decreased during the first several hours of repair, reaching a minimum level by 6 h; this decrease correlated temporally with the repair of the slowly rejoining DNA strand breaks. The possible relationship of DNA repair to changes in survival and chromosome aberrations is discussed

  19. The influence of DNA repair inhibitors on the mutation rate

    International Nuclear Information System (INIS)

    Auzinger, Th.; Hruby, R.

    1980-12-01

    The simultaneous influence of gamma-radiation and DNA-repair inhibiting substances on the mutation frequency of mice was investigated in vivo with the micronucleus test. The detergens Tween 80, vitamin A, and the antiphlogisticum phenylbutazone were used as DNA-repair inhibiting substances. Using the same irradiation doses, a statistic significant increase of mutagenicity respectively micronucleus frequency was found in high concentrations of Tween 80 and in all used dosages of vitamin A, but not in phenylbutazone and in low concentrations of tween. (auth.)

  20. Splitting methods in communication, imaging, science, and engineering

    CERN Document Server

    Osher, Stanley; Yin, Wotao

    2016-01-01

    This book is about computational methods based on operator splitting. It consists of twenty-three chapters written by recognized splitting method contributors and practitioners, and covers a vast spectrum of topics and application areas, including computational mechanics, computational physics, image processing, wireless communication, nonlinear optics, and finance. Therefore, the book presents very versatile aspects of splitting methods and their applications, motivating the cross-fertilization of ideas. .

  1. One-loop triple collinear splitting amplitudes in QCD

    Energy Technology Data Exchange (ETDEWEB)

    Badger, Simon; Buciuni, Francesco; Peraro, Tiziano [Higgs Centre for Theoretical Physics, School of Physics and Astronomy, University of Edinburgh,Edinburgh EH9 3JZ, Scotland (United Kingdom)

    2015-09-28

    We study the factorisation properties of one-loop scattering amplitudes in the triple collinear limit and extract the universal splitting amplitudes for processes initiated by a gluon. The splitting amplitudes are derived from the analytic Higgs plus four partons amplitudes. We present compact results for primitive helicity splitting amplitudes making use of super-symmetric decompositions. The universality of the collinear factorisation is checked numerically against the full colour six parton squared matrix elements.

  2. Application of Laser Micro-irradiation for Examination of Single and Double Strand Break Repair in Mammalian Cells.

    Science.gov (United States)

    Holton, Nathaniel W; Andrews, Joel F; Gassman, Natalie R

    2017-09-05

    Highly coordinated DNA repair pathways exist to detect, excise and replace damaged DNA bases, and coordinate repair of DNA strand breaks. While molecular biology techniques have clarified structure, enzymatic functions, and kinetics of repair proteins, there is still a need to understand how repair is coordinated within the nucleus. Laser micro-irradiation offers a powerful tool for inducing DNA damage and monitoring the recruitment of repair proteins. Induction of DNA damage by laser micro-irradiation can occur with a range of wavelengths, and users can reliably induce single strand breaks, base lesions and double strand breaks with a range of doses. Here, laser micro-irradiation is used to examine repair of single and double strand breaks induced by two common confocal laser wavelengths, 355 nm and 405 nm. Further, proper characterization of the applied laser dose for inducing specific damage mixtures is described, so users can reproducibly perform laser micro-irradiation data acquisition and analysis.

  3. A Novel Technique for Split-Thickness Skin Donor Site Pain Control: Subcutaneous Catheters for Continuous Local Anesthetic Infusion

    Science.gov (United States)

    2012-01-01

    the new: a novel approach to treating pain associated with rib fractures . World J Surg 2010;34:2359–62. 3. Wheatley GH III, Rosenbaum DH, Paul MC, et...has been described after laparotomy, tho- racotomy, inguinal hernia repair, and rib fractures .2–4 We describe our experience at the U.S. Army Insti...JAN 2012 2. REPORT TYPE N/A 3. DATES COVERED - 4. TITLE AND SUBTITLE A novel technique for split-thickness skin donor site pain control

  4. A Frequency Splitting Method For CFM Imaging

    DEFF Research Database (Denmark)

    Udesen, Jesper; Gran, Fredrik; Jensen, Jørgen Arendt

    2006-01-01

    The performance of conventional CFM imaging will often be degraded due to the relatively low number of pulses (4-10) used for each velocity estimate. To circumvent this problem we propose a new method using frequency splitting (FS). The FS method uses broad band chirps as excitation pulses instead...... of narrow band pulses as in conventional CFM imaging. By appropriate filtration, the returned signals are divided into a number of narrow band signals which are approximately disjoint. After clutter filtering the velocities are found from each frequency band using a conventional autocorrelation estimator......, a 5 MHz linear array transducer was used to scan a vessel situated at 30 mm depth with a maximum flow velocity of 0.1 m/s. The pulse repetition frequency was 1.8 kHz and the angle between the flow and the beam was 60 deg. A 15 mus chirp was used as excitation pulse and 40 independent velocity...

  5. Gray divorce: Explaining midlife marital splits.

    Science.gov (United States)

    Crowley, Jocelyn Elise

    2017-12-06

    Recent research suggests that one out of every four divorces in the United States is now "gray," meaning that at least one half of the couple has reached the age of 50 when the marriage breaks down. To understand why this age group-the Baby Boomer generation-is splitting up, this study conducted 40 in-depth, semistructured interviews with men and 40 with women who have experienced a gray divorce in their lifetimes. Respondents' beliefs in an expressive individualistic model of marriage, where partnerships are only valuable if they help individuals achieve personal growth, were compared against their potential adherence to what I call a commitment-based model of marriage, where binding, romantic love holds couples together unless there is severe relationship strain. The results demonstrated that the commitment-based model most strongly governs marriage and the decision to divorce among Baby Boomers for both sexes, although some specific reasons for divorce differ for men and women.

  6. Noncommutative instantons via dressing and splitting approaches

    International Nuclear Information System (INIS)

    Horvath, Zalan; Lechtenfeld, Olaf; Wolf, Martin

    2002-01-01

    Almost all known instanton solutions in noncommutative Yang-Mills theory have been obtained in the modified ADHM scheme. In this paper we employ two alternative methods for the construction of the self-dual U(2) BPST instanton on a noncommutative euclidean four-dimensional space with self-dual noncommutativity tensor. Firstly, we use the method of dressing transformations, an iterative procedure for generating solutions from a given seed solution, and thereby generalize Belavin's and Zakharov's work to the noncommutative setup. Secondly, we relate the dressing approach with Ward's splitting method based on the twistor construction and rederive the solution in this context. It seems feasible to produce nonsingular noncommutative multi-instantons with these techniques. (author)

  7. Promoting peripheral myelin repair.

    Science.gov (United States)

    Zhou, Ye; Notterpek, Lucia

    2016-09-01

    Compared to the central nervous system (CNS), peripheral nerves have a remarkable ability to regenerate and remyelinate. This regenerative capacity to a large extent is dependent on and supported by Schwann cells, the myelin-forming glial cells of the peripheral nervous system (PNS). In a variety of paradigms, Schwann cells are critical in the removal of the degenerated tissue, which is followed by remyelination of newly-regenerated axons. This unique plasticity of Schwann cells has been the target of myelin repair strategies in acute injuries and chronic diseases, such as hereditary demyelinating neuropathies. In one approach, the endogenous regenerative capacity of Schwann cells is enhanced through interventions such as exercise, electrical stimulation or pharmacological means. Alternatively, Schwann cells derived from healthy nerves, or engineered from different tissue sources have been transplanted into the PNS to support remyelination. These transplant approaches can then be further enhanced by exercise and/or electrical stimulation, as well as by the inclusion of biomaterial engineered to support glial cell viability and neurite extension. Advances in our basic understanding of peripheral nerve biology, as well as biomaterial engineering, will further improve the functional repair of myelinated peripheral nerves. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Mapping of repair genes

    International Nuclear Information System (INIS)

    Hori, Tadaaki

    1985-01-01

    Chromosome mapping of repair genes involved in U.V. sensitivity is reported. Twenty-three of 25 hybrid cells were resistant to U.V. light. Survival curves of 2 U.V.-resistant cell strains, which possessed mouse chromosomes and human chromosome No.7 - 16, were similar to those of wild strain (L5178Y). On the other hand, survival curves of U.V.-sensitive hybrid cells was analogous to those of Q31. There was a definitive difference in the frequency of inducible chromosome aberrations between U.V. resistant and sensitive mouse-human hybrid cells. U.V.-resistant cell strains possessed the ability of excision repair. Analysis of karyotype in hybrid cells showed that the difference in U.V. sensitivity is dependent upon whether or not human chromosome No.13 is present. Synteny test on esterase D-determining locus confirmed that there is an agreement between the presence of chromosome No.13 and the presence of human esterase D activity. These results led to a conclusion that human genes which compensate recessive character of U.V.-sensitive mutant strain, Q31, with mouse-human hybrid cells are located on the locus of chromosome No.13. (Namekawa, K.)

  9. Quantitation of the repair of gamma-radiation-induced double-strand DNA breaks in human fibroblasts

    International Nuclear Information System (INIS)

    Woods, W.G.

    1981-01-01

    The quantitation and repair of double-strand DNA breaks in human fibroblasts has been determined using a method involving the nondenaturing elution of DNA from a filter. DNA from cells from two human fibroblast lines exposed to γ-radiation from 0 to 10000 rad showed increasing retention on a filter with decreasing radiation dose, and the data suggest a linear relationship between double-strand breaks induced and radiation dose. The ability of normal human fibroblasts to repair double-strand breaks with various doses of radiation was demonstrated, with a tsub(1/2) of 10 min for repair of 5000 rad exposure and 39 min for repair of 10000 rad damage. The kinetics of the DNA rejoining were not linear and suggest that, as in the repair of single-strand breaks, both an initial fast and a later slow mechanism may be involved. (Auth.)

  10. Dose limits

    International Nuclear Information System (INIS)

    Fitoussi, L.

    1987-12-01

    The dose limit is defined to be the level of harmfulness which must not be exceeded, so that an activity can be exercised in a regular manner without running a risk unacceptable to man and the society. The paper examines the effects of radiation categorised into stochastic and non-stochastic. Dose limits for workers and the public are discussed

  11. Handbook of adhesive bonded structural repair

    CERN Document Server

    Wegman, Raymond F

    1992-01-01

    Provides repair methods for adhesive bonded and composite structures; identifies suitable materials and equipment for repairs; describes damage evaluation criteria and techniques, and methods of inspection before and after repair.

  12. [Constitutional mismatch repair deficiency syndrome

    NARCIS (Netherlands)

    Jongmans, M.C.J.; Gidding, C.E.M.; Loeffen, J.; Wesseling, P.; Mensenkamp, A.; Hoogerbrugge, N.

    2015-01-01

    BACKGROUND: Constitutional mismatch repair deficiency (CMMR-D) syndrome is characterised by a significantly increased risk for developing cancer in childhood. It arises when both parents have a mutation in the same mismatch repair gene and pass it on to their child. CASE DESCRIPTION: An 8-year-old

  13. Nucleotide excision repair in yeast

    NARCIS (Netherlands)

    Eijk, Patrick van

    2012-01-01

    Nucleotide Excision Repair (NER) is a conserved DNA repair pathway capable of removing a broad spectrum of DNA damage. In human cells a defect in NER leads to the disorder Xeroderma pigmentosum (XP). The yeast Saccharomyces cerevisiae is an excellent model organism to study the mechanism of NER. The

  14. My journey to DNA repair.

    Science.gov (United States)

    Lindahl, Tomas

    2013-02-01

    I completed my medical studies at the Karolinska Institute in Stockholm but have always been devoted to basic research. My longstanding interest is to understand fundamental DNA repair mechanisms in the fields of cancer therapy, inherited human genetic disorders and ancient DNA. I initially measured DNA decay, including rates of base loss and cytosine deamination. I have discovered several important DNA repair proteins and determined their mechanisms of action. The discovery of uracil-DNA glycosylase defined a new category of repair enzymes with each specialized for different types of DNA damage. The base excision repair pathway was first reconstituted with human proteins in my group. Cell-free analysis for mammalian nucleotide excision repair of DNA was also developed in my laboratory. I found multiple distinct DNA ligases in mammalian cells, and led the first genetic and biochemical work on DNA ligases I, III and IV. I discovered the mammalian exonucleases DNase III (TREX1) and IV (FEN1). Interestingly, expression of TREX1 was altered in some human autoimmune diseases. I also showed that the mutagenic DNA adduct O(6)-methylguanine (O(6)mG) is repaired without removing the guanine from DNA, identifying a surprising mechanism by which the methyl group is transferred to a residue in the repair protein itself. A further novel process of DNA repair discovered by my research group is the action of AlkB as an iron-dependent enzyme carrying out oxidative demethylation. Copyright © 2013. Production and hosting by Elsevier Ltd.

  15. The journey of DNA repair

    OpenAIRE

    Saini, Natalie

    2015-01-01

    21 years ago, the DNA Repair Enzyme was declared “Molecule of the Year”. Today, we are celebrating another “year of repair”, with the 2015 Nobel Prize in Chemistry being awarded to Aziz Sancar, Tomas Lindahl and Paul Modrich for their collective work on the different DNA repair pathways.

  16. DNA repair in mammalian cells exposed to combinations of carcinogenic agents

    International Nuclear Information System (INIS)

    Setlow, R.B.; Ahmed, F.E.

    1979-01-01

    Cells defective in one or more aspects of repair are killed and often mutagenized more readily than normal cells by DNA damaging agents, and humans whose cells are deficient in repair are at an increased carcinogenic risk compared to normal individuals. The excision repair of uv induced pyrimidine dimers is a well studied system, but the details of the steps in this repair system are far from being understood in human cells. We know that there are a number of chemicals that mimic uv in that normal human cells repair DNA damage from both these agents and from uv by a long patch excision repair system, and that xeroderma pigmentosum cells defective in repair of uv are also defective in the repair of damage from these chemicals. The chemicals we have investigated are AAAF, 4-NQO, DMBA-epoxide, and ICR-170. We describe experiments, using several techniques, in which DNA excision repair is measured after treatment of various human cell strains with combinations of uv and these agents. If two agents have a common rate limiting step then, at doses high enough to saturate the repair system, one would expect the observed repair after a treatment with a combination of agents to be equal to that from one agent alone. Such is not the case for normal human or excision-deficient XP cells. In the former repair is additive and in the latter repair is usually appreciably less than that observed with either agent alone. Models that attempt to explain these surprising results involve complexes of enzymes and cofactors

  17. Can the ''doublet-triplet splitting'' problem be solved without doublet-triplet splitting?

    International Nuclear Information System (INIS)

    Dvali, G.R.

    1992-03-01

    We consider a new possible mechanism for the natural solution of the doublet-triplet splitting problem in SUSY GUTs. In contrast to the usually discussed scenarios, in our case the GUT symmetry breaking does not provide any splitting between the Higgs doublet and the triplet masses. The weak doublet and its colour triplet partner both remain light, but the triplet automatically occurs decoupled from the quark and lepton superfields and cannot induce proton decay. The advantage of the above scenarios is the absence at the GUT scale of the baryon number violating the tree level d = 5 and d = 6 operators via the colour-triple exchange. It is shown that in flipped SU(5) GUT they do not appear at any scale. In the SO(10) model, such operators can be induced after SUSY breaking but are strongly suppressed. (author). 22 refs, 2 figs

  18. Dosimetric Comparison of Split Field and Fixed Jaw Techniques for Large IMRT Target Volumes in the Head and Neck

    International Nuclear Information System (INIS)

    Srivastava, Shiv P.; Das, Indra J.; Kumar, Arvind; Johnstone, Peter A.S.

    2011-01-01

    Some treatment planning systems (TPSs), when used for large-field (>14 cm) intensity-modulated radiation therapy (IMRT), create split fields that produce excessive multiple-leaf collimator segments, match-line dose inhomogeneity, and higher treatment times than nonsplit fields. A new method using a fixed-jaw technique (FJT) forces the jaw to stay at a fixed position during optimization and is proposed to reduce problems associated with split fields. Dosimetric comparisons between split-field technique (SFT) and FJT used for IMRT treatment is presented. Five patients with head and neck malignancies and regional target volumes were studied and compared with both techniques. Treatment planning was performed on an Eclipse TPS using beam data generated for Varian 2100C linear accelerator. A standard beam arrangement consisting of nine coplanar fields, equally spaced, was used in both techniques. Institutional dose-volume constraints used in head and neck cancer were kept the same for both techniques. The dosimetric coverage for the target volumes between SFT and FJT for head and neck IMRT plan is identical within ±1% up to 90% dose. Similarly, the organs at risk (OARs) have dose-volume coverage nearly identical for all patients. When the total monitor unit (MU) and segments were analyzed, SFT produces statistically significant higher segments (17.3 ± 6.3%) and higher MU (13.7 ± 4.4%) than the FJT. There is no match line in FJT and hence dose uniformity in the target volume is superior to the SFT. Dosimetrically, SFT and FJT are similar for dose-volume coverage; however, the FJT method provides better logistics, lower MU, shorter treatment time, and better dose uniformity. The number of segments and MU also has been correlated with the whole body radiation dose with long-term complications. Thus, FJT should be the preferred option over SFT for large target volumes.

  19. Bad splits in bilateral sagittal split osteotomy: systematic review and meta-analysis of reported risk factors.

    Science.gov (United States)

    Steenen, S A; van Wijk, A J; Becking, A G

    2016-08-01

    An unfavourable and unanticipated pattern of the bilateral sagittal split osteotomy (BSSO) is generally referred to as a 'bad split'. Patient factors predictive of a bad split reported in the literature are controversial. Suggested risk factors are reviewed in this article. A systematic review was undertaken, yielding a total of 30 studies published between 1971 and 2015 reporting the incidence of bad split and patient age, and/or surgical technique employed, and/or the presence of third molars. These included 22 retrospective cohort studies, six prospective cohort studies, one matched-pair analysis, and one case series. Spearman's rank correlation showed a statistically significant but weak correlation between increasing average age and increasing occurrence of bad splits in 18 studies (ρ=0.229; Pbad split among the different splitting techniques. A meta-analysis pooling the effect sizes of seven cohort studies showed no significant difference in the incidence of bad split between cohorts of patients with third molars present and concomitantly removed during surgery, and patients in whom third molars were removed at least 6 months preoperatively (odds ratio 1.16, 95% confidence interval 0.73-1.85, Z=0.64, P=0.52). In summary, there is no robust evidence to date to show that any risk factor influences the incidence of bad split. Copyright © 2016 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  20. Bad split during bilateral sagittal split osteotomy of the mandible with separators: a retrospective study of 427 patients.

    Science.gov (United States)

    Mensink, Gertjan; Verweij, Jop P; Frank, Michael D; Eelco Bergsma, J; Richard van Merkesteyn, J P

    2013-09-01

    An unfavourable fracture, known as a bad split, is a common operative complication in bilateral sagittal split osteotomy (BSSO). The reported incidence ranges from 0.5 to 5.5%/site. Since 1994 we have used sagittal splitters and separators instead of chisels for BSSO in our clinic in an attempt to prevent postoperative hypoaesthesia. Theoretically an increased percentage of bad splits could be expected with this technique. In this retrospective study we aimed to find out the incidence of bad splits associated with BSSO done with splitters and separators. We also assessed the risk factors for bad splits. The study group comprised 427 consecutive patients among whom the incidence of bad splits was 2.0%/site, which is well within the reported range. The only predictive factor for a bad split was the removal of third molars at the same time as BSSO. There was no significant association between bad splits and age, sex, class of occlusion, or the experience of the surgeon. We think that doing a BSSO with splitters and separators instead of chisels does not increase the risk of a bad split, and is therefore safe with predictable results. Copyright © 2012 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  1. Procedures for maintenance and repairs

    International Nuclear Information System (INIS)

    Pickel, E.

    1981-01-01

    After a general review of the operation experience in the history of more than 12 operating years, the organization in the plant will be shown with special aspect to quality assurance, capacity of the workshops and connected groups as radiation protection, chemical laboratories etc. The number, time intervals and manpower effort for the repeating tests will be discussed. Reasons and examples for back-fitting activities in the plant are given. Besides special repair and maintenance procedures as repair of the steam generators, in-service inspection of the reactor pressure vessel, repair of a feed-water pipe and repair of the core structure in the pressure vessel, the general system to handle maintenance and repair-work in the KWO-plant will be shown. This includes also the detailed planning of the annual refueling and revision of the plant. (orig./RW)

  2. Repair of potentially lethal and sublethal radiation damage in x-irradiated ascites tumor cells

    International Nuclear Information System (INIS)

    Tsuboi, Atsushi; Okamoto, Mieko; Tsuchiya, Takehiko.

    1985-01-01

    The ability of cells to repair cellular radiation damage during the growth of TMT-3 ascites tumor and the effect of host reaction on the repair ability were examined by using an in vitro assay of cell clonogenicity after in situ irradiation of tumor cells. In single-dose experiments, the repair of potentially lethal radiation damage (PLD) was observed in stationary phase cells (12-day tumor) of the unirradiated host, but not in exponential phase cells (3-day tumor) of the unirradiated host animals. However, if previously irradiated host animals were used, even the exponentially growing tumor cells showed repair of PLD. In two-dose experiments, the ability to repair sublethal radiation damage (SLD) in exponential phase tumor cells was less than that of stationary phase cells in the unirradiated host. In the pre-irradiated host, the extent of the repair in exponential phase cells was somewhat enhanced. These results suggest that irradiation of host animals might suppress a factor that inhibits repair, resulting in enhancement of the repair capability of tumor cells. (author)

  3. Effect of different doses of urea on the uptake of cadmium from soil ...

    African Journals Online (AJOL)

    Yomi

    2012-01-19

    Jan 19, 2012 ... uptake by canola (Brassica napus L.) applied in full and split doses. Nine different ... production of ruminants being reared on the pasture. Key words: ... combined nitrogen fertilizer used in today's agricultural practices ...

  4. Analysis of DNA strand break induction and repair in plants from the vicinity of Chernobyl

    International Nuclear Information System (INIS)

    Syomov, A.B.; Ptitsyna, S.N.; Sergeeva, S.A.

    1992-01-01

    For 3 years following the Chernobyl accident DNA repair efficiency was studied in irradiated and control populations of various plan species. Compared with the control populations, some irradiated populations exhibited increases in the yield of DNA single-strand breaks per unit dose of challenge radiation. The effect was registered in low-dose-rate alpha-irradiated populations, but was absent in plant populations growing in conditions of low-dose-rate beta-irradiation. The efficiency of single-strand DNA repair was identical in control and irradiated populations and approximated 100%. (author). 12 refs.; 1 fig.; 2 tabs

  5. Wound repair in Pocillopora

    Science.gov (United States)

    Rodríguez-Villalobos, Jenny Carolina; Work, Thierry M.; Calderon-Aguileraa, Luis Eduardo

    2016-01-01

    Corals routinely lose tissue due to causes ranging from predation to disease. Tissue healing and regeneration are fundamental to the normal functioning of corals, yet we know little about this process. We described the microscopic morphology of wound repair in Pocillopora damicornis. Tissue was removed by airbrushing fragments from three healthy colonies, and these were monitored daily at the gross and microscopic level for 40 days. Grossly, corals healed by Day 30, but repigmentation was not evident at the end of the study (40 d). On histology, from Day 8 onwards, tissues at the lesion site were microscopically indistinguishable from adjacent normal tissues with evidence of zooxanthellae in gastrodermis. Inflammation was not evident. P. damicornis manifested a unique mode of regeneration involving projections of cell-covered mesoglea from the surface body wall that anastomosed to form gastrovascular canals.

  6. Repairing Nanoparticle Surface Defects.

    Science.gov (United States)

    Marino, Emanuele; Kodger, Thomas E; Crisp, Ryan W; Timmerman, Dolf; MacArthur, Katherine E; Heggen, Marc; Schall, Peter

    2017-10-23

    Solar devices based on semiconductor nanoparticles require the use of conductive ligands; however, replacing the native, insulating ligands with conductive metal chalcogenide complexes introduces structural defects within the crystalline nanostructure that act as traps for charge carriers. We utilized atomically thin semiconductor nanoplatelets as a convenient platform for studying, both microscopically and spectroscopically, the development of defects during ligand exchange with the conductive ligands Na 4 SnS 4 and (NH 4 ) 4 Sn 2 S 6 . These defects can be repaired via mild chemical or thermal routes, through the addition of L-type ligands or wet annealing, respectively. This results in a higher-quality, conductive, colloidally stable nanomaterial that may be used as the active film in optoelectronic devices. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  7. Traumatic Tricuspid Insufficiency Requiring Valve Repair in an Acute Setting.

    Science.gov (United States)

    Enomoto, Yoshinori; Sudo, Yoshio; Sueta, Tomonori

    2015-01-01

    Tricuspid insufficiency due to penetrating cardiac trauma is rare. Patients with tricuspid insufficiency due to trauma can tolerate this abnormality for months or even years. We report a case of a 66-year-old female with penetrating cardiac trauma on the right side of her heart that required tricuspid valve repair in an acute setting. She sustained cut and stab wounds on her bilateral forearms and in the neck and epigastric region. She had cardiac tamponade and developed pulseless electrical activity, which required emergency surgery. The right ventricle and superior vena cava were dissected approximately 5 cm and 2 cm, respectively. After these wounds had been repaired, the patient's inability to wean from cardiopulmonary bypass suggested rightsided heart failure; transesophageal echocardiography revealed tricuspid insufficiency. Right atriotomy was performed, and a detailed examination revealed that the tricuspid valve septal leaflet was split in two. There was also an atrial septal injury that created a connection with the left atrium; these injuries were not detected from the right ventricular wound. After repair, weaning from cardiopulmonary bypass with mild tricuspid insufficiency was achieved, and she recovered uneventfully. This case emphasized the importance of thoroughly investigating intracardiac injury and transesophageal echocardiography.

  8. Reward optimization of a repairable system

    Energy Technology Data Exchange (ETDEWEB)

    Castro, I.T. [Departamento de Matematicas, Facultad de Veterinaria, Universidad de Extremadura, Avenida de la Universidad, s/n. 10071 Caceres (Spain)]. E-mail: inmatorres@unex.es; Perez-Ocon, R. [Departamento de Estadistica e Investigacion Operativa, Facultad de Ciencias, Universidad de Granada, Avenida de Severo Ochoa, s/n. 18071 Granada (Spain)]. E-mail: rperezo@ugr.es

    2006-03-15

    This paper analyzes a system subject to repairable and non-repairable failures. Non-repairable failures lead to replacement of the system. Repairable failures, first lead to repair but they lead to replacement after a fixed number of repairs. Operating and repair times follow phase type distributions (PH-distributions) and the pattern of the operating times is modelled by a geometric process. In this context, the problem is to find the optimal number of repairs, which maximizes the long-run average reward per unit time. To this end, the optimal number is determined and it is obtained by efficient numerical procedures.

  9. Reward optimization of a repairable system

    International Nuclear Information System (INIS)

    Castro, I.T.; Perez-Ocon, R.

    2006-01-01

    This paper analyzes a system subject to repairable and non-repairable failures. Non-repairable failures lead to replacement of the system. Repairable failures, first lead to repair but they lead to replacement after a fixed number of repairs. Operating and repair times follow phase type distributions (PH-distributions) and the pattern of the operating times is modelled by a geometric process. In this context, the problem is to find the optimal number of repairs, which maximizes the long-run average reward per unit time. To this end, the optimal number is determined and it is obtained by efficient numerical procedures

  10. The role of prophylactic cefazolin in the prevention of infection after various types of abdominal wall hernia repair with mesh

    Directory of Open Access Journals (Sweden)

    Mostafa Mehrabi Bahar

    2015-07-01

    Conclusion: Preoperative administration of single-dose cefazolin for prosthetic hernia repairs did not markedly decrease the risk of wound infection. Our results do not support the use of cefazolin as a prophylactic antibiotic for various kinds of abdominal wall hernia repair with mesh.

  11. Three-part head-splitting proximal humerus fracture through a unicameral bone cyst.

    Science.gov (United States)

    Younghein, John A; Eskander, Mark S; DeAngelis, Nicola A; Wixted, John J

    2012-06-01

    Unicameral bone cysts are rare in adults and are most often found incidentally on radiographs. However, they can persist from the adolescent period and may be present in locations that predispose to or exacerbate fractures.This article describes a case of a healthy 40-year-old woman who sustained a proximal humerus trauma that involved a large unicameral bone cyst, resulting in a 3-part head-splitting fracture. The epiphyseal location of the cyst contributed to the severity and extent of the fracture that resulted from a simple fall. Given the age of the patient, open reduction and internal fixation with a locking plate and lag screws was performed. The patient chose open reduction and internal fixation to preserve a hemiarthroplasty procedure in case of future revision. Successful humeral head reconstruction was achieved, and the patient fully recovered. One year postoperatively, the patient underwent arthroscopic debridement to alleviate subjective stiffness and decreased range of motion.Multipart head-splitting fractures require complex repair strategies. The gold standard for the treatment of these injuries is hemiarthroplasty. However, the decision process is difficult in a young patient given the average survival of autoplastic prostheses and the added difficulty of later revision. The current case demonstrates the complexity of decision making resulting from a rare injury in a young, healthy patient and shows that open reduction and internal fixation can provide acceptable reconstruction in such situations. Copyright 2012, SLACK Incorporated.

  12. Photocatalytic Water-Splitting Reaction from Catalytic and Kinetic Perspectives

    KAUST Repository

    Hisatomi, Takashi

    2014-10-16

    Abstract: Some particulate semiconductors loaded with nanoparticulate catalysts exhibit photocatalytic activity for the water-splitting reaction. The photocatalysis is distinct from the thermal catalysis because photocatalysis involves photophysical processes in particulate semiconductors. This review article presents a brief introduction to photocatalysis, followed by kinetic aspects of the photocatalytic water-splitting reaction.Graphical Abstract: [Figure not available: see fulltext.

  13. Dye-sensitized photocatalyst for effective water splitting catalyst

    Science.gov (United States)

    Watanabe, Motonori

    2017-12-01

    Renewable hydrogen production is a sustainable method for the development of next-generation energy technologies. Utilising solar energy and photocatalysts to split water is an ideal method to produce hydrogen. In this review, the fundamental principles and recent progress of hydrogen production by artificial photosynthesis are reviewed, focusing on hydrogen production from photocatalytic water splitting using organic-inorganic composite-based photocatalysts.

  14. Giant Rashba spin splitting in Bi2Se3: Tl

    KAUST Repository

    Singh, Nirpendra; Saeed, Yasir; Schwingenschlö gl, Udo

    2014-01-01

    First-principles calculations are employed to demonstrate a giant Rashba spin splitting in Bi2Se3:Tl. Biaxial tensile and compressive strain is used to tune the splitting by modifying the potential gradient. The band gap is found to increase under

  15. Towards Highly Efficient Bias-Free Solar Water Splitting

    NARCIS (Netherlands)

    Abdi, F.F.

    2013-01-01

    Solar water splitting has attracted significant attention due to its potential of converting solar to chemical energy. It uses semiconductor to convert sunlight into electron-hole pairs, which then split water into hydrogen and oxygen. The hydrogen can be used as a renewable fuel, or it can serve as

  16. The Effectiveness of Managing Split Attention among Autistic Children

    Science.gov (United States)

    Aliee, Zeinab Shams; Jomhari, Nazean; Rezaei, Reza; Alias, Norlidah

    2013-01-01

    One of the most common problems in autistic children is split attention. Split attention prevents autism children from being able to focus attention on their learning, and tasks. As a result, it is important to identify how to make autistic individuals focus attention on learning. Considering autistic individuals have higher visual abilities in…

  17. Irradiation-induced amorphization in split-dislocation cores

    International Nuclear Information System (INIS)

    Ovid'ko, I.A.; Rejzis, A.B.

    1999-01-01

    The model describing special splitting of lattice and grain-boundary dislocations as one of the micromechanisms of solid-phase amorphization in irradiated crystals is proposed. Calculation of energy characteristics of the process of dislocations special splitting is carried out [ru

  18. April / May 2006. 108 Harvesting split thickness skin in

    African Journals Online (AJOL)

    user

    Background: In the third world countries like Ethiopia the majority of Hospitals have difficulties in harvesting split thickness skin ... The grafts were well taken by the recipient areas and technically there was no danger of deep bite. Conclusion: Split ... to meet the hospital needs. Thus we need to improvise and use appropriate.

  19. Splitting in Dual-Phase 590 high strength steel plates

    International Nuclear Information System (INIS)

    Yang Min; Chao, Yuh J.; Li Xiaodong; Tan Jinzhu

    2008-01-01

    Charpy V-notch impact tests on 5.5 mm thick, hot-rolled Dual-Phase 590 (DP590) steel plate were evaluated at temperatures ranging from 90 deg. C to -120 deg. C. Similar tests on 2.0 mm thick DP590 HDGI steel plate were also conducted at room temperature. Splitting or secondary cracks was observed on the fractured surfaces. The mechanisms of the splitting were then investigated. Fracture surfaces were analyzed by optical microscope (OM) and scanning electron microscope (SEM). Composition of the steel plates was determined by electron probe microanalysis (EPMA). Micro Vickers hardness of the steel plates was also surveyed. Results show that splitting occurred on the main fractured surfaces of hot-rolled steel specimens at various testing temperatures. At temperatures above the ductile-brittle-transition-temperature (DBTT), -95 deg. C, where the fracture is predominantly ductile, the length and amount of splitting decreased with increasing temperature. At temperatures lower than the DBTT, where the fracture is predominantly brittle, both the length and width of the splitting are insignificant. Splitting in HDGI steel plates only appeared in specimens of T-L direction. The analysis revealed that splitting in hot-rolled plate is caused by silicate and carbide inclusions while splitting in HDGI plate results from strip microstructure due to its high content of manganese and low content of silicon. The micro Vickers hardness of either the inclusions or the strip microstructures is higher than that of the respective base steel

  20. Clonal differences in log end splitting in Eucalyptus grandis in ...

    African Journals Online (AJOL)

    This paper discusses the juvenile–mature correlation of log end splitting among Eucalyptus grandis clones from two trials and how differences in splitting relate to differences in wood density, pith-to-bark gradient and growth rate. Two approximately 20-year-old Eucalyptus grandis clonal trials at Bergvliet plantation were ...

  1. Linear expansion of products out of thermal splitting graphite

    International Nuclear Information System (INIS)

    Tishina, E.A.; Kurnevich, G.I.

    1994-01-01

    Linear expansion of thermally split graphite in the form of foil and pressed items of different density was studied. It is ascertained that the extreme character of temperature dependence of linear expansion factor of pressed samples of thermally split graphite is determined by the formation of closed pores containing air in the course of their production. 3 refs., 2 figs

  2. 77 FR 8127 - Foreign Tax Credit Splitting Events

    Science.gov (United States)

    2012-02-14

    ... Tax Credit Splitting Events AGENCY: Internal Revenue Service (IRS), Treasury. ACTION: Final and... affect taxpayers claiming foreign tax credits. The text of the temporary regulations also serves as the... that if there is a foreign tax credit splitting event with respect to a foreign income tax paid or...

  3. 77 FR 8184 - Foreign Tax Credit Splitting Events

    Science.gov (United States)

    2012-02-14

    ... Foreign Tax Credit Splitting Events AGENCY: Internal Revenue Service (IRS), Treasury. ACTION: Notice of... these proposed regulations. The regulations affect taxpayers claiming foreign tax credits. Special... of the Federal Register.] Sec. 1.909-6 Pre-2011 foreign tax credit splitting events. [The text of...

  4. Nonlocal Cooper pair splitting in a pSn-junction

    NARCIS (Netherlands)

    Veldhorst, M.; Brinkman, Alexander

    2010-01-01

    Perfect Cooper pair splitting is proposed, based on crossed Andreev reflection (CAR) in a p-type semiconductor-superconductor-n-type semiconductor (pSn) junction. The ideal splitting is caused by the energy filtering that is enforced by the band structure of the electrodes. The pSn junction is

  5. Split-liver transplantation : An underused resource in liver transplantation

    NARCIS (Netherlands)

    Rogiers, Xavier; Sieders, Egbert

    2008-01-01

    Split-liver transplantation is an efficient tool to increase the number of liver grafts available for transplantation. More than 15 years after its introduction only the classical splitting technique has reached broad application. Consequently children are benefiting most from this possibility.

  6. Optimal space-energy splitting in MCNP with the DSA

    International Nuclear Information System (INIS)

    Dubi, A.; Gurvitz, N.

    1990-01-01

    The Direct Statistical Approach (DSA) particle transport theory is based on the possibility of obtaining exact explicit expressions for the dependence of the second moment and calculation time on the splitting parameters. This allows the automatic optimization of the splitting parameters by ''learning'' the bulk parameters from which the problem dependent coefficients of the quality function (second moment time) are constructed. The above procedure was exploited to implement an automatic optimization of the splitting parameters in the Monte Carlo Neutron Photon (MCNP) code. This was done in a number of steps. In the first instance, only spatial surface splitting was considered. In this step, the major obstacle has been the truncation of an infinite series of ''products'' of ''surface path's'' leading from the source to the detector. Encouraging results from the first phase led to the inclusion of full space/energy phase space splitting. (author)

  7. Conditional Toxin Splicing Using a Split Intein System.

    Science.gov (United States)

    Alford, Spencer C; O'Sullivan, Connor; Howard, Perry L

    2017-01-01

    Protein toxin splicing mediated by split inteins can be used as a strategy for conditional cell ablation. The approach requires artificial fragmentation of a potent protein toxin and tethering each toxin fragment to a split intein fragment. The toxin-intein fragments are, in turn, fused to dimerization domains, such that addition of a dimerizing agent reconstitutes the split intein. These chimeric toxin-intein fusions remain nontoxic until the dimerizer is added, resulting in activation of intein splicing and ligation of toxin fragments to form an active toxin. Considerations for the engineering and implementation of conditional toxin splicing (CTS) systems include: choice of toxin split site, split site (extein) chemistry, and temperature sensitivity. The following method outlines design criteria and implementation notes for CTS using a previously engineered system for splicing a toxin called sarcin, as well as for developing alternative CTS systems.

  8. Exposing the QCD Splitting Function with CMS Open Data.

    Science.gov (United States)

    Larkoski, Andrew; Marzani, Simone; Thaler, Jesse; Tripathee, Aashish; Xue, Wei

    2017-09-29

    The splitting function is a universal property of quantum chromodynamics (QCD) which describes how energy is shared between partons. Despite its ubiquitous appearance in many QCD calculations, the splitting function cannot be measured directly, since it always appears multiplied by a collinear singularity factor. Recently, however, a new jet substructure observable was introduced which asymptotes to the splitting function for sufficiently high jet energies. This provides a way to expose the splitting function through jet substructure measurements at the Large Hadron Collider. In this Letter, we use public data released by the CMS experiment to study the two-prong substructure of jets and test the 1→2 splitting function of QCD. To our knowledge, this is the first ever physics analysis based on the CMS Open Data.

  9. Optimizing TCP Performance over UMTS with Split TCP Proxy

    DEFF Research Database (Denmark)

    Hu, Liang; Dittmann, Lars

    2009-01-01

    . To cope with large delay bandwidth product, we propose a novel concept of split TCP proxy which is placed at GGSN between UNITS network and Internet. The split proxy divides the bandwidth delay product into two parts, resulting in two TCP connections with smaller bandwidth delay products which can...... be pipelined and thus operating at higher speeds. Simulation results show, the split TCP proxy can significantly improve the TCP performance in terms of RLC throughput under high bit rate DCH channel scenario (e.g.256 kbps). On the other hand, it only brings small performance improvement under low bit rate DCH...... scenario (e.g.64 kbps). Besides, the split TCP proxy brings more performance gain for downloading large files than downloading small ones. To the end, for the configuration of the split proxy, an aggressive initial TCP congestion window size (e.g. 10 MSS) at proxy is particularly useful for radio links...

  10. Split-plot fractional designs: Is minimum aberration enough?

    DEFF Research Database (Denmark)

    Kulahci, Murat; Ramirez, Jose; Tobias, Randy

    2006-01-01

    Split-plot experiments are commonly used in industry for product and process improvement. Recent articles on designing split-plot experiments concentrate on minimum aberration as the design criterion. Minimum aberration has been criticized as a design criterion for completely randomized fractional...... factorial design and alternative criteria, such as the maximum number of clear two-factor interactions, are suggested (Wu and Hamada (2000)). The need for alternatives to minimum aberration is even more acute for split-plot designs. In a standard split-plot design, there are several types of two...... for completely randomized designs. Consequently, we provide a modified version of the maximum number of clear two-factor interactions design criterion to be used for split-plot designs....

  11. Split-plot designs for robotic serial dilution assays.

    Science.gov (United States)

    Buzas, Jeffrey S; Wager, Carrie G; Lansky, David M

    2011-12-01

    This article explores effective implementation of split-plot designs in serial dilution bioassay using robots. We show that the shortest path for a robot to fill plate wells for a split-plot design is equivalent to the shortest common supersequence problem in combinatorics. We develop an algorithm for finding the shortest common supersequence, provide an R implementation, and explore the distribution of the number of steps required to implement split-plot designs for bioassay through simulation. We also show how to construct collections of split plots that can be filled in a minimal number of steps, thereby demonstrating that split-plot designs can be implemented with nearly the same effort as strip-plot designs. Finally, we provide guidelines for modeling data that result from these designs. © 2011, The International Biometric Society.

  12. Photoelectrochemical solar water splitting: From basic principles to advanced devices

    Directory of Open Access Journals (Sweden)

    Bandar Y.Alfaifi

    2018-02-01

    Full Text Available Photoelectrochemical water splitting (PEC offers a promising path for sustainable generation of hydrogen fuel. However, improving solar fuel water splitting efficiency facing tremendous challenges, due to the energy loss related to fast recombination of the photogenerated charge carriers, electrode degradation, as well as limited light harvesting. This review focuses on the brief introduction of basic fundamental of PEC water splitting and the concept of various types of water splitting approaches. Numerous engineering strategies for the investgating of the higher efficiency of the PEC, including charge separation, light harvesting, and co-catalysts doping, have been discussed. Moreover, recent remarkable progress and developments for PEC water splitting with some promising materials are discussed. Recent advanced applications of PEC are also reviewed. Finally, the review concludes with a summary and future outlook of this hot field.

  13. Residual stress by repair welds

    International Nuclear Information System (INIS)

    Mochizuki, Masahito; Toyoda, Masao

    2003-01-01

    Residual stress by repair welds is computed using the thermal elastic-plastic analysis with phase-transformation effect. Coupling phenomena of temperature, microstructure, and stress-strain fields are simulated in the finite-element analysis. Weld bond of a plate butt-welded joint is gouged and then deposited by weld metal in repair process. Heat source is synchronously moved with the deposition of the finite-element as the weld deposition. Microstructure is considered by using CCT diagram and the transformation behavior in the repair weld is also simulated. The effects of initial stress, heat input, and weld length on residual stress distribution are studied from the organic results of numerical analysis. Initial residual stress before repair weld has no influence on the residual stress after repair treatment near weld metal, because the initial stress near weld metal releases due to high temperature of repair weld and then stress by repair weld regenerates. Heat input has an effect for residual stress distribution, for not its magnitude but distribution zone. Weld length should be considered reducing the magnitude of residual stress in the edge of weld bead; short bead induces high tensile residual stress. (author)

  14. Controllable dose

    International Nuclear Information System (INIS)

    Alvarez R, J.T.; Anaya M, R.A.

    2004-01-01

    With the purpose of eliminating the controversy about the lineal hypothesis without threshold which found the systems of dose limitation of the recommendations of ICRP 26 and 60, at the end of last decade R. Clarke president of the ICRP proposed the concept of Controllable Dose: as the dose or dose sum that an individual receives from a particular source which can be reasonably controllable by means of any means; said concept proposes a change in the philosophy of the radiological protection of its concern by social approaches to an individual focus. In this work a panorama of the foundations is presented, convenient and inconveniences that this proposal has loosened in the international community of the radiological protection, with the purpose of to familiarize to our Mexican community in radiological protection with these new concepts. (Author)

  15. Repair replication in cultured normal and transformed human fibroblasts

    International Nuclear Information System (INIS)

    Smith, C.A.; Hanawalt, P.C.

    1976-01-01

    Repair replication in response to ultraviolet irradiation has been studied in normal human diploid fibroblast cultures, W138, and an SV40 transformant, VA13. Quantitative comparisons have been made using the combined isotopic and density labelling method for assaying repair replication. No significant difference was found in the amount of repair replication performed, its dose response, or the time course between growing and confluent W138 cells, early passage and senescent cells, or normal W138 cells and the transformed VA13 cells. When [ 3 H]dThd was employed as the isotopic label in the presence of a 30-200 fold excess of unlabelled BrdUrd apparent differences in repair replication were seen between W138 cells shortly after subcultivation and cells which had been allowed to reach confluence. These differences were the same over a wide dose range and regardless of the passage number of the cells, but could be influenced by using different serum lots. The differences were not seen, however, when [ 3 H]BrdUrd provided the isotopic label; thus they reflect either impurities in the [ 3 H]dThd or a slight discrimination by some cellular process

  16. Influence of postoperative low-level laser therapy on the osseointegration of self-tapping implants in the posterior maxilla: a 6-week split-mouth clinical study.

    Science.gov (United States)

    Mandić, Borka; Lazić, Zoran; Marković, Aleksa; Mandić, Bojan; Mandić, Miška; Djinić, Ana; Miličić, Biljana

    2015-03-01

    Low-level laser therapy (LLLT) has been proven to stimulate bone repair, affecting cellular proliferation, differentiation and adhesion, and has shown a potential to reduce the healing time following implant placement. The aim of this clinical study was to investigate the influence of postoperative LLLT osseointegration and early success of self-tapping implants placed into low-density bone. Following the split-mouth design, self-tapping implants n = 44) were inserted in the posterior maxilla of 12 patients. One jaw side randomly received LLLT (test group), while the other side was placebo (control group). For LLLT, a 637 nm gallium-aluminum-arsenide (GaAlAs) laser (Medicolaser 637, Technoline, Belgrade, Serbia) with an output power of 40 mW and continuous wave was used. Low-level laser treatment was performed immediately after the surgery and then repeated every day in the following 7 days. The total irradiation dose per treatment was 6.26 J/cm2 per implant. The study outcomes were: implant stability, alkaline-phosphatase (ALP) activity and early implant success rate. The follow-up took 6 weeks. Irradiated implants achieved a higher stability compared with controls during the entire follow-up and the difference reached significance in the 5th postoperative week (paired t-test, p = 0.030). The difference in ALP activity between the groups was insignificant in any observation point (paired t-test, p > 0.05). The early implant success rate was 100%, regardless of LLLT usage. LLLT applied daily during the first postoperative week expressed no significant influence on the osseointegration of self-tapping implants placed into low density bone of the posterior maxilla. Placement of self-tapping macro-designed implants into low density bone could be a predictable therapeutic procedure with a high early success rate regardless of LLLT usage.

  17. Influence of postoperative low-level laser therapy on the osseointegration of self-tapping implants in the posterior maxilla: A 6-week split-mouth clinical study

    Directory of Open Access Journals (Sweden)

    Mandić Borka

    2015-01-01

    Full Text Available Background/Aim. Low-level laser therapy (LLLT has been proven to stimulate bone repair, affecting cellular proliferation, differentiation and adhesion, and has shown a potential to reduce the healing time following implant placement. The aim of this clinical study was to investigate the influence of postoperative LLLT osseointegration and early success of self-tapping implants placed into low-density bone. Methods. Following the split-mouth design, self-tapping implants (n = 44 were inserted in the posterior maxilla of 12 patients. One jaw side randomly received LLLT (test group, while the other side was placebo (control group. For LLLT, a 637 nm gallium-aluminum-arsenide (GaAlAs laser (Medicolaser 637, Technoline, Belgrade, Serbia with an output power of 40 mW and continuous wave was used. Low-level laser treatment was performed immediately after the surgery and then repeated every day in the following 7 days. The total irradiation dose per treatment was 6.26 J/cm² per implant. The study outcomes were: implant stability, alkaline-phosphatase (ALP activity and early implant success rate. The follow-up took 6 weeks. Results. Irradiated implants achieved a higher stability compared with controls during the entire follow-up and the difference reached significance in the 5th postoperative week (paired t-test, p = 0.030. The difference in ALP activity between the groups was insignificant in any observation point (paired t-test, p > 0.05. The early implant success rate was 100%, regardless of LLLT usage. Conclusion. LLLT applied daily during the first postoperative week expressed no significant influence on the osseointegration of selftapping implants placed into low density bone of the posterior maxilla. Placement of self-tapping macro-designed implants into low density bone could be a predictable therapeutic procedure with a high early success rate regardless of LLLT usage.

  18. Split-Field Magnet facility upgraded

    CERN Multimedia

    CERN PhotoLab

    1977-01-01

    The Split Field Magnet (SFM) was the largest spectrometer for particles from beam-beam collisions in the ISR. It could determine particle momenta in a large solid angle, but was designed mainly for the analysis of forward travelling particles.As the magnet was working on the ISR circulating beams, its magnetic field had to be such as to restore the correct proton orbit.The SFM, therefore, produced zero field at the crossing point and fields of opposite signs upstream and downstream of it and was completed by 2 large and 2 small compensator magnets. The gradient effects were corrected by magnetic channels equipped with movable flaps. The useful magnetic field volume was 28 m3, the induction in the median plane 1.14 T, the gap heigth 1.1 m, the length 10.5 m, the weight about 1000 ton. Concerning the detectors, the SFM was the first massive application of multiwire proportional chambers (about 70000 wires) which filled the main and the large compensator magnets. In 1976 an improved programme was started with tw...

  19. Field-Split Preconditioned Inexact Newton Algorithms

    KAUST Repository

    Liu, Lulu

    2015-06-02

    The multiplicative Schwarz preconditioned inexact Newton (MSPIN) algorithm is presented as a complement to additive Schwarz preconditioned inexact Newton (ASPIN). At an algebraic level, ASPIN and MSPIN are variants of the same strategy to improve the convergence of systems with unbalanced nonlinearities; however, they have natural complementarity in practice. MSPIN is naturally based on partitioning of degrees of freedom in a nonlinear PDE system by field type rather than by subdomain, where a modest factor of concurrency can be sacrificed for physically motivated convergence robustness. ASPIN, originally introduced for decompositions into subdomains, is natural for high concurrency and reduction of global synchronization. We consider both types of inexact Newton algorithms in the field-split context, and we augment the classical convergence theory of ASPIN for the multiplicative case. Numerical experiments show that MSPIN can be significantly more robust than Newton methods based on global linearizations, and that MSPIN can be more robust than ASPIN and maintain fast convergence even for challenging problems, such as high Reynolds number Navier--Stokes equations.

  20. Markov branching in the vertex splitting model

    International Nuclear Information System (INIS)

    Stefánsson, Sigurdur Örn

    2012-01-01

    We study a special case of the vertex splitting model which is a recent model of randomly growing trees. For any finite maximum vertex degree D, we find a one parameter model, with parameter α element of [0,1] which has a so-called Markov branching property. When D=∞ we find a two parameter model with an additional parameter γ element of [0,1] which also has this feature. In the case D = 3, the model bears resemblance to Ford's α-model of phylogenetic trees and when D=∞ it is similar to its generalization, the αγ-model. For α = 0, the model reduces to the well known model of preferential attachment. In the case α > 0, we prove convergence of the finite volume probability measures, generated by the growth rules, to a measure on infinite trees which is concentrated on the set of trees with a single spine. We show that the annealed Hausdorff dimension with respect to the infinite volume measure is 1/α. When γ = 0 the model reduces to a model of growing caterpillar graphs in which case we prove that the Hausdorff dimension is almost surely 1/α and that the spectral dimension is almost surely 2/(1 + α). We comment briefly on the distribution of vertex degrees and correlations between degrees of neighbouring vertices

  1. Field-Split Preconditioned Inexact Newton Algorithms

    KAUST Repository

    Liu, Lulu; Keyes, David E.

    2015-01-01

    The multiplicative Schwarz preconditioned inexact Newton (MSPIN) algorithm is presented as a complement to additive Schwarz preconditioned inexact Newton (ASPIN). At an algebraic level, ASPIN and MSPIN are variants of the same strategy to improve the convergence of systems with unbalanced nonlinearities; however, they have natural complementarity in practice. MSPIN is naturally based on partitioning of degrees of freedom in a nonlinear PDE system by field type rather than by subdomain, where a modest factor of concurrency can be sacrificed for physically motivated convergence robustness. ASPIN, originally introduced for decompositions into subdomains, is natural for high concurrency and reduction of global synchronization. We consider both types of inexact Newton algorithms in the field-split context, and we augment the classical convergence theory of ASPIN for the multiplicative case. Numerical experiments show that MSPIN can be significantly more robust than Newton methods based on global linearizations, and that MSPIN can be more robust than ASPIN and maintain fast convergence even for challenging problems, such as high Reynolds number Navier--Stokes equations.

  2. A split operator method for transient problems

    International Nuclear Information System (INIS)

    Belytschko, T.B.

    1983-01-01

    Numerous techniques have been developed for improving the computational efficiency of transient analysis: mesh partitioning, subcycling procedures and operator splitting methods. In mesh partitioning methods, the model is divided into subdomains which are integrated by different time integrators, typically implicit and explicit. Any stiff portions of the model are integrated by the implicit operator so that the size of the time step can be increased. In subcycling procedures, the stiff portions are integrated by smaller time steps, yielding similar benefits. However, in models for which the governing partial differential equations are basically of a parabolic character, explicit methods can become quite expensive for refined models because the size of the stable time step decreases with the square of the minimum element dimension. Thus explicit methods, whether employed alone or with partitioning or subcycling, have inherent limitations in these problems. A new procedure is here described for the element-by-element semi-implicit method of Hughes and coworkers which requires the solution of only small systems of equations. This procedure is described for a family of uniform gradient or strain elements which are widely used in nonlinear transient analysis. The diffusion equation and the equations of motion for both shells and continua have been treated, but only the former is considered herein. Results are presented for several examples which show the potential of this method for improving the efficiency of a large-scale linear and nonlinear computations. (orig./RW)

  3. Protracted radiation-induced alterations in hematopoietic repair and recovery

    International Nuclear Information System (INIS)

    Seed, T.M.; Fritz, T.E.

    1997-01-01

    Pathologic predisposition of beagle dogs under chronic, low daily dose (7.5 cGy day -1 ) whole-body gamma irradiation has been studied relative to molecular repair and hematopoietic competency. Molecular repair, assessed by a microscopy-based unscheduled DNA synthesis (UDS) response, was measured within proliferative and nonproliferative marrow myeloid elements of dogs with markedly different hematopoietic capacities (low capacity, aplasia-prone [AA + ] versus high capacity, myeloproliferative disease-prone [MPD + ]) under protracted radiation stress. Results indicated that protracted exposure elicited a net increase in UDS-repair capacity that was largely independent of exposure duration. This enhanced capacity resulted from the increased strength of the UDS signal together with an expanded number of positively responding cells. The combined response was strong in primitive blasts and weak in more differentiated myelocytic cells. The UDS repair response of the MPD + dogs was significantly greater than that of the AA + animals and was clearly modified relative to the controls. These results suggest that both resiliency and pathologic potential of the hematopoietic system under protracted radiation stress is, in part, associated with an augmentable DNA repair within the more primitive myeloid marrow elements. (author)

  4. Occupational doses and ALARA - recent developments in Sweden

    Energy Technology Data Exchange (ETDEWEB)

    Godas, T.; Viktorsson, C. [Swedish Radiation Protection Institute, Stockholm (Sweden)

    1995-03-01

    Sweden has traditionally experienced very slow doses to workers in the nuclear industry. However, this trend has since last year been broken mainly due to significant maintenance and repair work. This paper will describe occupational dose trends in Sweden and discuss actions that are being implemented to control this new situation.

  5. Repair-dependent cell radiation survival and transformation: an integrated theory

    International Nuclear Information System (INIS)

    Sutherland, John C

    2014-01-01

    The repair-dependent model of cell radiation survival is extended to include radiation-induced transformations. The probability of transformation is presumed to scale with the number of potentially lethal damages that are repaired in a surviving cell or the interactions of such damages. The theory predicts that at doses corresponding to high survival, the transformation frequency is the sum of simple polynomial functions of dose; linear, quadratic, etc, essentially as described in widely used linear-quadratic expressions. At high doses, corresponding to low survival, the ratio of transformed to surviving cells asymptotically approaches an upper limit. The low dose fundamental- and high dose plateau domains are separated by a downwardly concave transition region. Published transformation data for mammalian cells show the high-dose plateaus predicted by the repair-dependent model for both ultraviolet and ionizing radiation. For the neoplastic transformation experiments that were analyzed, the data can be fit with only the repair-dependent quadratic function. At low doses, the transformation frequency is strictly quadratic, but becomes sigmodial over a wider range of doses. Inclusion of data from the transition region in a traditional linear-quadratic analysis of neoplastic transformation frequency data can exaggerate the magnitude of, or create the appearance of, a linear component. Quantitative analysis of survival and transformation data shows good agreement for ultraviolet radiation; the shapes of the transformation components can be predicted from survival data. For ionizing radiations, both neutrons and x-rays, survival data overestimate the transforming ability for low to moderate doses. The presumed cause of this difference is that, unlike UV photons, a single x-ray or neutron may generate more than one lethal damage in a cell, so the distribution of such damages in the population is not accurately described by Poisson statistics. However, the complete

  6. Differential effect of ionizing radiation on transcription in repair-deficient and repair-proficient mice

    International Nuclear Information System (INIS)

    Munson, G.P.; Woloschak, G.E.

    1990-01-01

    Experiments were designed to examine in vivo changes in total transcription and in the expression of the c-fos gene following whole-body exposure of mice to JANUS fission-spectrum neutrons. Radiation repair-deficient (wst/wst) and -proficient (wst/., C57BL/6 x C3H F1) mice were exposed to JANUS fission-spectrum neutrons calibrated to deliver a gut dose of 50 cGy. Animals were sacrificed less than 10 or at 60 min postirradiation, and gut tissues were removed for study. Our results revealed that, in repair-proficient mice, an immediate depression (relative to untreated control) in total transcription was evident that continued through 1 h postirradiation. Conversely, radiation-sensitive wst/wst mice displayed doubled transcription levels postirradiation. Expression of c-fos was consistently depressed following radiation exposure in control and wst/wst mice. However, the depression of c-fos mRNA was delayed in wst/wst mice relative to controls. These results demonstrate abnormal regulation of transcription and of c-fos mRNA accumulation in repair-deficient wasted mice following exposure to ionizing radiation. In addition, this work documents rapid total transcriptional depression in normal mice following radiation exposure

  7. Urease inhibitor (NBPT and efficiency of single or split application of urea in wheat crop

    Directory of Open Access Journals (Sweden)

    Marcelo Curitiba Espindula

    2014-04-01

    Full Text Available NBPT (N-(n-butyl thiophosphoric triamide, a urease inhibitor, has been reported as one of the most promising compounds to maximize urea nitrogen use in agricultural systems. The objective of this study was to evaluate the performance of irrigated wheat fertilized with urea or urea + NBPT as single or split application. The experiment was conducted from June to October 2006 in Viçosa, MG, Brazil. The experimental design followed a 2×2 factorial scheme, in which urea or urea + NBPT were combined with two modes of application: full dose at sowing (60kg ha-1 or split (20kg ha-1 at sowing + 40kg ha-1 as topdressing at tillering, in randomized blocks with ten replications. The split application of nitrogen fertilization does not improve the yield wheat under used conditions. The use of urease inhibitor improves the grain yield of wheat crop when urea is applied in topdressing at tillering, but its use does not promote difference when urea is applied in the furrow at planting.

  8. Models of mixed irradiation with a 'reciprocal-time' pattern of the repair function

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Shozo; Miura, Yuri; Mizuno, Shoichi [Tokyo Metropolitan Inst. of Gerontology (Japan); Furusawa, Yoshiya [National Inst. of Radiological Sciences, Chiba (Japan)

    2002-09-01

    Suzuki presented models for mixed irradiation with two and multiple types of radiation by extending the Zaider and Rossi model, which is based on the theory of dual radiation action. In these models, the repair function was simply assumed to be semi-logarithmically linear (i.e., monoexponential), or a first-order process, which has been experimentally contradicted. Fowler, however, suggested that the repair of radiation damage might be largely a second-order process rather than a first-order one, and presented data in support of this hypothesis. In addition, a second-order repair function is preferred to an n-exponential repair function for the reason that only one parameter is used in the former instead of 2n-1 parameters for the latter, although both repair functions show a good fit to the experimental data. However, according to a second-order repair function, the repair rate depends on the dose, which is incompatible with the experimental data. We, therefore, revised the models for mixed irradiation by Zaider and Rossi and by Suzuki, by substituting a 'reciprocal-time' pattern of the repair function, which is derived from the assumption that the repair rate is independent of the dose in a second-order repair function, for a first-order one in reduction and interaction factors of the models, although the underlying mechanism for this assumption cannot be well-explained. The reduction factor, which reduces the contribution of the square of a dose to cell killing in the linear-quadratic model and its derivatives, and the interaction factor, which also reduces the contribution of the interaction of two or more doses of different types of radiation, were formulated by using a 'reciprocal-time' patterns of the repair function. Cell survivals calculated from the older and the newly modified models were compared in terms of the dose-rate by assuming various types of single and mixed irradiation. The result implies that the newly modified models for

  9. Monogenic diseases of DNA repair

    DEFF Research Database (Denmark)

    Keijzers, Guido; Bakula, Daniela; Scheibye-Knudsen, Morten

    2017-01-01

    Maintaining the stability of the genome is essential for all organisms, and it is not surprising that damage to DNA has been proposed as an explanation for multiple chronic diseases.1-5 Conserving a pristine genome is therefore of central importance to our health. To overcome the genotoxic stress...... of a growing number of human diseases. Notably, many of these monogenic DNA-repair disorders display features of accelerated aging, supporting the notion that genome maintenance is a key factor for organismal longevity. This review focuses on the physiological consequences of loss of DNA repair, particularly...... in the context of monogenic DNA-repair diseases....

  10. Repairing and Upgrading Your PC

    CERN Document Server

    Thompson, Robert

    2009-01-01

    Repairing and Upgrading Your PC delivers start-to-finish instructions, simple enough for even the most inexperienced PC owner, for troubleshooting, repairing, and upgrading your computer. Written by hardware experts Robert Bruce Thompson and Barbara Fritchman Thompson, this book covers it all: how to troubleshoot a troublesome PC, how to identify which components make sense for an upgrade, and how to tear it all down and put it back together. This book shows how to repair and upgrade all of your PC's essential components.

  11. 40 CFR 798.5500 - Differential growth inhibition of repair proficient and repair deficient bacteria: “Bacterial DNA...

    Science.gov (United States)

    2010-07-01

    ... repair proficient and repair deficient bacteria: âBacterial DNA damage or repair tests.â 798.5500 Section... inhibition of repair proficient and repair deficient bacteria: “Bacterial DNA damage or repair tests.” (a... killing or growth inhibition of repair deficient bacteria in a set of repair proficient and deficient...

  12. Role of DNA damage repair capacity in radiation induced adaptive response

    International Nuclear Information System (INIS)

    Yuan Dexiao; Pan Yan; Zhao Meijia; Chen Honghong; Shao Cunlin

    2009-01-01

    This work was to explore γ-ray induced radioadaptive response (RAR) in Chinese hamster ovary(CHO) cell lines of different DNA damage repair capacities. CHO-9 cells and the two repair-deficient strains, EM-C11(DNA single strand break repair deficient) and XR-C1(DNA double strand break repair deficient), were irradiated with a priming dose of 0.08 Gy or 0.016 Gy. After 4 or 7 hours, they were irradiated again with a challenging dose of 1 Gy. The micronucleus induction and plating efficiency of the cells were assayed. Under 0.08 Gy priming dose and 4-h interval, just the CHO-9 cells showed RAR, while with the 7-h interval the CHO-9 and EM-C11 showed RAR, but XR-C1 did not. When the cells were pretreated with a lower priming dose of 0.016 Gy in a 4-h time interval, all the three cell lines showed RAR to subsequent 1 Gy irradiation. It can be concluded that RAR is not only related to the priming dose and time interval, but also has close dependence on the ability of DNA damage repair. (authors)

  13. Ultraviolet-induced DNA excision repair in human B and T lymphocytes. II

    International Nuclear Information System (INIS)

    Yew, F.F.-H.; Johnson, R.T.

    1979-01-01

    Despite their great sensitivity to ultraviolet light purified human B and T lymphocytes are capable of complete repair provided that the ultraviolet dose does not exceed 0.5 Jm -2 . Their capacity to repair, as measured by the restoration of DNA supercoiling in preparations of nucleoids, and their survival are significantly increased in the presence of deoxyribonucleosides. Certain agents which inhibit semi-conservative DNA synthesis (hydroxyurea, 1-β-D-arabino-furanosylcytosine (arafCyt) either stop or delay the repair process in lymphocytes. The effect of hydroxyurea is eventually overcome spontaneously, but changes in the sedimentation behaviour of ultraviolet-irradiated nucleoids caused by arafCyt can only be neutralized by addition of deoxycytidine. The effective inhibition of repair by arafCyt permits the detection of extremely small amounts of ultraviolet damage and also the estimation of when repair is complete. (Auth.)

  14. Tune splitting in the presence of linear coupling

    International Nuclear Information System (INIS)

    Parzen, G.

    1991-01-01

    The presence of random skew quadrupole field errors will couple the x and y motions. The x and y motions are then each given by the sum of 2 normal modes with the tunes v 1 and v 2 , which may differ appreciably from v x and v y , the unperturbed tunes. This is often called tune splitting since |v 1 - v 2 | is usually larger than |v x - v y |. This tune splitting may be large in proton accelerators using superconducting magnets, because of the relatively large random skew quadrupole field errors that are expected in these magnets. This effect is also increased by the required insertions in proton colliders which generate large β-functions in the insertion region. This tune splitting has been studied in the RHIC accelerator. For RHIC, a tune splitting as large as 0.2 was found in one worse case. A correction system has been developed for correcting this large tune splitting which uses two families of skew quadrupole correctors. It has been found that this correction system corrects most of the large tune splitting, but a residual tune splitting remains that is still appreciable. This paper discusses the corrections to this residual time

  15. Splitting of turbulent spot in transitional pipe flow

    Science.gov (United States)

    Wu, Xiaohua; Moin, Parviz; Adrian, Ronald J.

    2017-11-01

    Recent study (Wu et al., PNAS, 1509451112, 2015) demonstrated the feasibility and accuracy of direct computation of the Osborne Reynolds' pipe transition problem without the unphysical, axially periodic boundary condition. Here we use this approach to study the splitting of turbulent spot in transitional pipe flow, a feature first discovered by E.R. Lindgren (Arkiv Fysik 15, 1959). It has been widely believed that spot splitting is a mysterious stochastic process that has general implications on the lifetime and sustainability of wall turbulence. We address the following two questions: (1) What is the dynamics of turbulent spot splitting in pipe transition? Specifically, we look into any possible connection between the instantaneous strain rate field and the spot splitting. (2) How does the passive scalar field behave during the process of pipe spot splitting. In this study, the turbulent spot is introduced at the inlet plane through a sixty degree wide numerical wedge within which fully-developed turbulent profiles are assigned over a short time interval; and the simulation Reynolds numbers are 2400 for a 500 radii long pipe, and 2300 for a 1000 radii long pipe, respectively. Numerical dye is tagged on the imposed turbulent spot at the inlet. Splitting of the imposed turbulent spot is detected very easily. Preliminary analysis of the DNS results seems to suggest that turbulent spot slitting can be easily understood based on instantaneous strain rate field, and such spot splitting may not be relevant in external flows such as the flat-plate boundary layer.

  16. Kinetics and capacity of repair of sublethal damage in mouse lip mucosa during fractionated irradiations

    International Nuclear Information System (INIS)

    Ang, K.K.; Xu, F.X.; Landuyt, W.; van der Schueren, E.

    1985-01-01

    The kinetics and capacity of repair of sublethal damage in mouse lip mucosa have been investigated. To assess the rate of repair 2 and 5 irradiations have been given with intervals ranging from 1 to 24 hours. It was found that the sublethal damage induced by a dose of approximately 10 Gy was fully recovered in approximately 4 hr. After a dose of 5-6 Gy, cellular repair was completed within 3 hr. The half time of repair (T1/2) was estimated to be approximately 72 min for 10 Gy and approximately 54 min for 5-6 Gy. Although these results suggest that the rate of repair is dependent on the fraction size, the possible influence of the amount of repair of sublethal radiation damage with the various fraction sizes used can not be ruled out. To evaluate the capacity of repair, a single dose, 2, 4 and 10 fractions have been given in a maximal overall time of 3 days in order to minimize the influence of repopulation. The slope of the isoeffective curve was 0.32 and the alpha/beta ratio was 8.5 Gy. This indicates that the capacity of cellular repair of lip mucosa is similar to those of other rapidly proliferating tissues but smaller than those of late responding tissues. The results of the present and other studies demonstrate that there are considerable differences in the repair characteristics between acutely and late responding tissues. These features have to be dealt with when fractionation schedules are markedly altered

  17. Innovative repair of subsidence damage

    International Nuclear Information System (INIS)

    Marino, G.G.

    1992-01-01

    In order to improve handling of subsidence damages the Illinois Mine Subsidence Insurance Fund supported the development of novel cost-effective methods of repair. The research in developing the repairs was directed towards the most common and costly damages that had been observed. As a result repair techniques were designed for structurally cracked foundations in the tension zone; structurally cracked foundations in the compression zone; and damaged or undamaged tilted foundations. When appropriate the postulated methods would result in: 1. significant cost savings (over conventional procedures); 2. a structural capacity greater than when the foundation was uncracked; and 3. an aesthetic appeal. All the postulated repair methodologies were laboratory and/or field tested. This paper will summarize the essentials of each technique developed and the test results

  18. Umbilical hernia repair - series (image)

    Science.gov (United States)

    ... treatment. The indications for umbilical hernia repair include: incarcerated (strangulated) umbilical hernia defects not spontaneously closed by 4 to 5 years of age children under 2 with very large defects unacceptable to ...

  19. Mammalian DNA Repair. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Richard D.

    2003-01-24

    The Gordon Research Conference (GRC) on Mammalian DNA Repair was held at Harbortown Resort, Ventura Beach, CA. Emphasis was placed on current unpublished research and discussion of the future target areas in this field.

  20. Canadian company innovates dam repair

    International Nuclear Information System (INIS)

    Anon.

    2000-01-01

    Successful repair without any downtime, of the Sabana Yegua power and irrigation structure in the western Dominican Republic by Aquatic Sciences Ltd., a St. Catherine, Ontario-based underwater specialist company, is discussed. The structure was damaged by Hurricane George last when when rising water levels damaged a major valve in the control gate chamber. The repair strategy designed by Aquatic Sciences used a remotely operated vehicle with a mechanical arm for minor tasks which placed a specially-made plug into the inlet pipe. The work was completed in one week, saving the utility company a great deal of money by making it possible to make the repairs remotely in the gate chamber without having to drain the tunnel, as would have been necessary had the repair been completed manually. The remotely operated vehicles use a scanning sonar as well as light to find their way. They are particularly well adapted to work underwater under low-visibility conditions