Science.gov

Sample records for irradiation effectively suppresses

  1. Carbon-Ion Beam Irradiation Effectively Suppresses Migration and Invasion of Human Non-Small-Cell Lung Cancer Cells

    SciTech Connect

    Akino, Yuichi; Teshima, Teruki Kihara, Ayaka; Kodera-Suzumoto, Yuko; Inaoka, Miho; Higashiyama, Shigeki; Furusawa, Yoshiya; Matsuura, Nariaki

    2009-10-01

    Purpose: Control of cancer metastasis is one of the most important issues in cancer treatment. We previously demonstrated that carbon particle irradiation suppresses the metastatic potential of cancer cells, and many studies have reported that photon irradiation promotes it. The purpose of this study was to investigate the effect of carbon beam on non-small-cell lung cancer (NSCLC) cell aggressiveness and gene expression. Methods and Materials: A549 (lung adenocarcinoma) and EBC-1 (lung squamous cell carcinoma) cells were treated with 290 MeV/nucleon carbon ion beam at the Heavy Ion Medical Accelerator in Chiba or with 4-MV X-ray at Osaka University. We tested proliferative, migratory, and invasive activities by cell proliferation assay, Boyden chamber assay, and Matrigel chemoinvasion assay, respectively. cDNA microarray and reverse transcription polymerase chain reaction were also performed to assess mRNA expression alteration. Results: X-irradiation increased cell proliferation of A549 cells at 0.5 Gy, whereas high-dose X-ray reduced migration and invasion of A549 cells. By contrast, carbon beam irradiation did not enhance proliferation, and it reduced the migration and invasion capabilities of both A549 and EBC-1 cells more effectively than did X-irradiation. Carbon beam irradiation induced alteration of various gene expression profiles differently from X-ray irradiation. mRNA expression of ANLN, a homologue of anillin, was suppressed to 60% levels of basal expression in carbon beam-irradiated A549 cells after 12 h. Conclusion: Carbon beam effectively suppresses the metastatic potential of A549 and EBC-1 cells. Carbon beam also has different effects on gene expressions, and downregulation of ANLN was induced only by carbon beam irradiation.

  2. Suppressive Effect of Dietary Fucoidan on Proinflammatory Immune Response and MMP-1 Expression in UVB-Irradiated Mouse Skin.

    PubMed

    Maruyama, Hiroko; Tamauchi, Hidekazu; Kawakami, Fumitaka; Yoshinaga, Keiko; Nakano, Takahisa

    2015-10-01

    It is well known that ultraviolet B irradiation leads to dermal inflammation. In this study, we found that Mekabu fucoidan suppressed edema, decreased the thickness of the prickle cell layer, and decreased matrix metalloproteinase 1 in the skin of mice irradiated with ultraviolet B. Moreover, we found that the mean level of interferon gamma of Mekabu fucoidan-treated, ultraviolet B-irradiated mice (approximately 2.2 ng/mL) was not significantly different from that in normal mice (approximately 2.5 ng/mL). In contrast, a significant decrease in the mean level of interferon gamma (approximately 1.3 ng/mL) in ultraviolet B-irradiated control mice was observed compared with that in Mekabu fucoidan-treated, ultraviolet B-irradiated mice. The mean thickness of the prickle cell layer in the skin of Mekabu fucoidan-treated, ultraviolet B-irradiated mice was less than that in the ultraviolet B-irradiated control mice. Metalloproteinase 1 activity was significantly higher in the skin of ultraviolet B-irradiated mice than in the skin of untreated, nonirradiated normal mice. Metalloproteinase 1 in the skin of ultraviolet B-irradiated, Mekabu fucoidan- or L(+)-ascorbic acid (vitamin C)-treated mice was significantly lower than that in the ultraviolet B-irradiated control mice. Mitigation of the morphological changes in Mekabu fucoidan-treated mice was correlated with a decrease in metalloproteinase 1 levels. These data indicate that Mekabu fucoidan is an effective suppressor of inflammation in an ultraviolet B-irradiated mouse model.

  3. Effect of ion irradiation on nanoscale TiS2 systems with suppressed Titania phase

    NASA Astrophysics Data System (ADS)

    Hazarika, Saurabh J.; Mohanta, Dambarudhar; Tripathi, A.; Kanjilal, D.

    2016-10-01

    Titanium disulfide (TiS2), being an important of the transition metal dichalcogenide, (TMDC) family, has drawn numerous interest owing to exhibition of tunable band gap as well as high carrier mobility. In this work, we highlight preparation of TiS2 nanopowder with minimal TiO2 content and also demonstrate modified properties upon swift heavy ion irradiation on TiS2 nanoparticles dispersed PVA films. Different properties of the irradiated samples have been characterized through diffraction, microscopic and spectroscopic techniques. As a result of irradiation, due to agglomeration of particles, the grain size is found to increase. We could also observe a red shift after irradiation with increasing fluence, leading to easy flow of electron from valence to conduction band, which shows that conduction of electrons is more in case of irradiated films compared to the pristine one and thus there may be a possibility of using the irradiated samples in various optoelectronic devices.

  4. Suppression effect of nano-sized oxide particles on helium irradiation hardening in F82H-ODS steel

    NASA Astrophysics Data System (ADS)

    Chen, S.; Wang, Y.; Tadaki, K.; Hashimoto, N.; Ohnuki, S.

    2014-12-01

    Helium implantation was performed to investigate irradiation hardening in ferritic/martensitic steels. Depth dependence of nano-hardness was obtained using a Berkovich nano-indenter, and then nano-hardness was extracted from Nix-Gao model. The correlation between irradiation hardening and the concentration 500-2000 appm of helium was plotted. Nano-hardness increases as a function of helium concentration. F82H-ODS with a higher nano-hardness provides a lower irradiation hardening than F82H-IEA. Cross-sectional transmission electron microscopy (XTEM) revealed that cavities with a uniform distribution were formed after helium implantation at 2000 appm helium concentration, showing a mean size of 1.1 nm with an average number density of 4.9 × 1023 m-3 in F82H-IEA and 1.3 nm with 7.4 × 1023 m-3 in F82H-ODS. Orowan model was applied to evaluate the hardening from dispersed cavities. The significant difference of hardening between calculation and nano-indentation result of F82H-ODS indicates that oxide particles may shield the hardening effect from cavities because of the complex multi-interaction.

  5. Effects of far infrared rays irradiated from ceramic material (BIOCERAMIC) on psychological stress-conditioned elevated heart rate, blood pressure, and oxidative stress-suppressed cardiac contractility.

    PubMed

    Leung, Ting-Kai; Chen, Chien-Ho; Tsai, Shih-Ying; Hsiao, George; Lee, Chi-Ming

    2012-10-31

    The present study examined the effects of BIOCERAMIC on psychological stress-conditioned elevated heart rate, blood pressure and oxidative stress-suppressed cardiac contractility using in vivo and in vitro animal models. We investigated the effects of BIOCERAMIC on the in vivo cardiovascular hemodynamic parameters of rats by monitoring their heart rates, systolic blood pressure, mean blood pressure and diastolic blood pressure. Thereafter, we assayed its effects on the heart rate in an isolated frog heart with and without adrenaline stimulation, and on cardiac contractility under oxidative stress. BIOCERAMIC caused significant decreases in heart rates and systolic and mean blood pressure in the stress-conditioned heart rate rat models (P < 0.05), as well as in the experimental models of an isolated frog heart with and without adrenaline stimulation (P < 0.05), and normalized cardiac contractility under oxidative stress (P < 0.05). BIOCERAMIC may, therefore, normalize the effects of psychological stress and oxidative stress conditions.

  6. Factors influencing dust suppressant effectiveness

    SciTech Connect

    Copeland, C.R.; Eisele, T.C.; Chesney, D.J.; Kawatra, S.K.

    2008-11-15

    Water sprays are a common method used to reduce particulate matter (PM) emissions. Various factors such as wettability, surface area coverage, fine particle engulfment rates, interparticle adhesion forces, suppressant penetration and suppressant longevity have all been suggested as critical factors in achieving effective PM control. However, it has not been established which of these factors are the most important. Experimental work indicated that suppressant penetration is the most critical of these factors. The length of time after application that suppressants were effective was also improved by using hygroscopic reagents that retained moisture to prevent evaporation. Maximizing suppressant penetration and improving suppressant longevity led to an average 86% reduction in PM10 concentrations in laboratory dust tower tests.

  7. Suppressed histamine release from rat peritoneal mast cells by ultraviolet B irradiation: decreased diacylglycerol formation as a possible mechanism

    SciTech Connect

    Danno, K.; Fujii, K.; Tachibana, T.; Toda, K.; Horio, T.

    1988-06-01

    This study was designed to investigate the effect of ultraviolet B (UVB) irradiation on mast cell functions. Purified mast cells obtained from rat peritoneal cavity were irradiated with UVB and subsequently exposed to a degranulator, compound 48/80, or the calcium ionophore A-23187. The amount of histamine released from mast cells measured by the enzyme isotopic assay was significantly decreased by UVB irradiation (100-400 mJ/cm2). Within this dose range, UVB alone was not cytotoxic to the cells because it did not induce histamine release. The suppression was observed when mast cells were subjected to degranulation without intervals after UVB irradiation, and even after 5 h postirradiation. The wavelength of 300 nm from a monochromatic light source showed the maximum effect. When mast cells prelabeled with (/sup 3/H)arachidonate were irradiated and challenged by compound 48/80, label accumulation in diacylglycerol produced by the phosphatidylinositol cycle was considerably decreased by UVB irradiation. From these results, we hypothesize that, within an adequate irradiation dose, UVB irradiation suppresses histamine release from mast cells, probably by causing noncytotoxic damage to the membrane phospholipid metabolism, which is tied to the degranulation mechanisms.

  8. Effects of Laser Irradiation on Peripheral Nerve

    NASA Astrophysics Data System (ADS)

    Baxter, G. D.; Chow, R.; Armati, P.; Bjordal, J. M.; Laakso, L.

    2009-06-01

    A literature review was undertaken to determine the electrophysiological effects of Laser Irradiation (LI) on peripheral mammalian nerves, as a means of elucidating the potential mechanisms underlying pain relief associated with laser therapy. Relevant computerized databases and reference lists were searched, and experts consulted for further articles. A total of 38 studies, comprising 82 separate experiments were identified. In human studies, all types of LI (red and infrared, pulsed and cw) slowed nerve conduction velocity, and reduced compound action potential of irradiated nerves. In animal studies, infrared LI suppressed conduction velocity, as well as noxious stimulation evoked potential. This review thus indicates the potential of laser irradiation to inhibit activity in peripheral nerves, and highlights one potential mechanism of action for laser-mediated pain relief.

  9. Ultraviolet-irradiated urocanic acid suppresses delayed-type hypersensitivity to herpes simplex virus in mice

    SciTech Connect

    Ross, J.A.; Howie, S.E.; Norval, M.; Maingay, J.; Simpson, T.J.

    1986-11-01

    Ultraviolet radiation is known to induce a transient defect in epidermal antigen presentation which leads to the generation of antigen-specific suppression of the delayed-type hypersensitivity (DTH) response. The putative receptor in skin for the primary event in UV-suppression is urocanic acid (UCA) which may then interact locally, or systemically, with antigen presenting cells or initiate a cascade of events resulting in suppression. We present the first direct evidence that UCA, when irradiated with a dose (96 mJ/cm2) of UVB radiation known to suppress the DTH response to herpes simplex virus, type 1 (HSV-1) in mice, can induce suppression following epidermal application or s.c. injection of the irradiated substance. This suppression is transferable with nylon wool-passed spleen cells.

  10. Mechanism of rapid suppression of cell expansion in cucumber hypocotyls after blue-light irradiation

    NASA Technical Reports Server (NTRS)

    Cosgrove, D. J.

    1988-01-01

    Rapid suppression of hypocotyl elongation by blue light in cucumber (Cucumis sativus L.) was studied to examine possible hydraulic and wall changes responsible for diminished growth. Cell-sap osmotic pressure, measured by vapor-pressure osmometry, was not decreased by blue light; turgor pressure, measured by the pressure-probe technique, remained constant during the growth inhibition; and stem hydraulic conductance, measured by dynamic and static methods, was likewise unaffected by blue light. Wall yielding properties were assessed by the pressure-block technique for in-vivo stress relaxation. Blue light reduced the initial rate of relaxation by 77%, but had little effect on the final amount of relaxation. The results demonstrate that blue irradiation acts to decrease the wall yielding coefficient, but not the yield threshold. Stress-strain (Instron) analysis showed that irradiation of the seedlings had little effect on the mechanical extensibilities of the isolated wall. The results indicate that blue light can reduce cell-wall loosening without affecting bulk viscoelastic properties, and indicate a chemorheological mechanism of cell-wall expansion.

  11. Thyroid-Stimulating Hormone Suppression for Protection Against Hypothyroidism Due to Craniospinal Irradiation for Childhood Medulloblastoma/Primitive Neuroectodermal Tumor

    SciTech Connect

    Massimino, Maura Gandola, Lorenza; Collini, Paola; Seregni, Ettore; Marchiano, Alfonso; Serra, Annalisa; Pignoli, Emanuele Ph.D.; Spreafico, Filippo; Pallotti, Federica; Terenziani, Monica; Biassoni, Veronica; Bombardieri, Emilio; Fossati-Bellani, Franca

    2007-10-01

    Purpose: Hypothyroidism is one of the earliest endocrine effects of craniospinal irradiation (CSI). The effects of radiation also depend on circulating thyroid-stimulating hormone (TSH), which acts as an indicator of thyrocyte function and is the most sensitive marker of thyroid damage. Hence, our study was launched in 1998 to evaluate the protective effect of TSH suppression during CSI for medulloblastoma/primitive neuroectodermal tumor. Patients and Methods: From Jan 1998 to Feb 2001, a total of 37 euthyroid children scheduled for CSI for medulloblastoma/primitive neuroectodermal tumor underwent thyroid ultrasound and free triiodothyronine (FT3), free thyroxine (FT4), and TSH evaluation at the beginning and end of CSI. From 14 days before and up to the end of CSI, patients were administered L-thyroxine at suppressive doses; every 3 days, TSH suppression was checked to ensure a value <0.3 {mu}M/ml. During follow-up, blood tests and ultrasound were repeated after 1 year; primary hypothyroidism was considered an increased TSH level greater than normal range. CSI was done using a hyperfractionated accelerated technique with total doses ranging from 20.8-39 Gy; models were used to evaluate doses received by the thyroid bed. Results: Of 37 patients, 25 were alive a median 7 years after CSI. They were well matched for all clinical features, except that eight children underwent adequate TSH suppression during CSI, whereas 17 did not. Hypothyroidism-free survival rates were 70% for the 'adequately TSH-suppressed' group and 20% for the 'inadequately TSH-suppressed' group (p = 0.02). Conclusions: Thyroid-stimulating hormone suppression with L-thyroxine had a protective effect on thyroid function at long-term follow-up. This is the first demonstration that transient endocrine suppression of thyroid activity may protect against radiation-induced functional damage.

  12. Effects of irradiation on PVC compounds

    NASA Astrophysics Data System (ADS)

    Bataille, P.; Ulkem, I.; Schreiber, H. P.

    1995-11-01

    PVC compounds containing CaCO 3 filler and plasticizers were prepared with or without a trifunctional acrylic crosslinking agent and irradiated by 60Co γ-rays under air or nitrogen atmosphere. The samples without crosslinking agent did not respond to irradiation. The mechanical properties of the other samples such as tensile strength, yield strength and % elongation showed a great sensitivity to irradiation. Lower values of Young's modulus were observed for samples irradiated in air compared with samples irradiated in nitrogen indicating the effect of atmosphere in the range of irradiation studied.

  13. Survival of primates following orthotopic cardiac transplantation treated with total lymphoid irradiation and chemical immune suppression

    SciTech Connect

    Pennock, J.L.; Reitz, B.A.; Bieber, C.P.; Aziz, S.; Oyer, P.E.; Strober, S.; Hoppe, R.; Kaplan, H.S.; Stinson, E.B.; Shumway, N.E.

    1981-12-01

    Fractionated total lymphoid irradiation (TLI) has been used for attempts at induction of a donor-specific tolerant-like state in allograft recipients and for immunosuppressive effects. Cyclosporin A (Cy A) has been shown to suppress rejection of organ grafts in many species including man. The present study was designed to test the effectiveness of TLI in combination with either CY A or rabbit anticynomolgus thymocyte globulin (ATG) and azathioprine. Thirty-one orthotopic cardiac allografts were performed using surface cooling and total circulatory arrest in outbred cynomolgus monkeys. TLI was administered preoperatively in fractions of 100 rad until a total of 600 or 1800 rad was achieved. Cy A was administered 17 mg/kg/day. All treatment groups demonstrated extended survival. Myocardial biopsies as early as 4 weeks were consistent with mild rejection in all treatment groups. No significant synergistic effect upon survival could be demonstrated utilizing TLI plus Cy A when compared with using Cy A alone. TLI (1800 rad) plus ATG and azathioprine was associated with a high incidence of early death attributable to leukopenia and infection. Cy A alone or in combination with TLI was associated with the development of lymphoid malignancy.

  14. Survival of primates following orthotopic cardiac transplantation treated with total lymphoid irradiation and chemical immune suppression

    SciTech Connect

    Pennock, J.L.; Reitz, B.A.; Beiber, C.P.; Aziz, S.; Oyer, P.E.; Strober, S.; Hoppe, R.; Kaplan, H.S.; Stinson, E.B.; Shumway, N.E.

    1981-12-01

    Fractionated total lymphoid irradiation (TLI) has been used for attempts at induction of a donor-specific tolerant-like state in allograft recipients and for immunosuppressive effects. Cyclosporin A (Cy A) has been shown to suppress rejection of organ grafts in many species including man. The present study was designed to test the effectiveness of TLI in combination with either Cy A or rabbit anticynomolgus thymocyte globulin (ATG) and azathioprine. Thirty-one orthotopic cardiac allografts were performed using surface cooling and total circulatory arrest in outbred cynomolgus monkeys. TLI was administered preoperatively in fractions of 100 rad until a total of 600 or 1800 rad was achieved. Cy A was administered 17 mg/kg/day. All treatment groups demonstrated extended survival. Myocardial biopsies as early as 4 weeks were consistent with mild rejection in all treatment groups. No significant synergistic effect upon survival could be demonstrated utilizing TLI (1800 rad) plus ATG and azathioprine was associated with a high incidence of early death attributable to leukopenia and infection. Cy A alone or in combination with TLI was associated with the development of lymphoid malignancy.

  15. Swelling suppression in phosphorous-modified Fe-Cr-Ni alloys during neutron irradiation

    SciTech Connect

    Lee, E.H.; Packan, N.H.

    1988-01-01

    Phosphorous-containing austenitic alloys in the solution annealed condition were irradiated at 745--760/degree/K. The alloys were variations on Fe--13Cr--15Ni--0.05P with respective additions of 0.8 Si, 0.2 Ti, or 0.8 Si /plus/ 0.2 Ti; also included were low (0.01) and zero P compositions (all values in wt. %). The reference ternary and the two phosphorous-only variations contained little precipitation and numerous voids and swelled rapidly, while the three variants containing P with Si and/or Ti showed little or no void formation and profuse phosphide precipitation. Results indicate that phosphorous in solution alone does not have a major influence on void swelling, whereas fine-scale phosphide precipitation is quite effective at eliminating void formation. The principal mechanism restricting swelling is the effect of the dense precipitate microstructure. These precipitates foster profuse cavity nucleation which in turn dilutes the helium atoms (and more time) in order for individual cavities to surpass their critical size and number of gas atoms necessary for subsequent growth as voids. This mechanism for swelling suppression was not found to be particularly sensitive to moderate variations in either the dislocation or cavity densities; the mechanism is strongest at elevated temperature where the critical quantities are large and is less effective at lower temperatures where the critical quantities are small. 19 refs., 10 figs., 3 tabs.

  16. Suppression of unprimed T and B cells in antibody responses by irradiation-resistant and plastic-adherent suppressor cells in Toxoplasma gondii-infected mice

    SciTech Connect

    Suzuki, Y.; Kobayashi, A.

    1983-04-01

    In the acute phase of Toxoplasma infection, the function of both helper T and B cells was suppressed in primary antibody responses to dinitrophenol (DNP)-conjugated protein antigens. During the course of infection, the suppressive effect on T cells seems to continue longer than that on B cells, since suppression in responses to sheep erythrocytes, a T-dependent antigen, persisted longer than those to DNP-Ficoll, a T-independent antigen. Plastic-adherent cells from the spleens of Toxoplasma-infected and X-irradiated (400 rads) mice had strong suppressor activity in primary anti-sheep erythrocyte antibody responses of normal mouse spleen cells in vitro. These data suggest that the activation of irradiation-resistant and plastic-adherent suppressor cells causes the suppression of both T and B cells in Toxoplasma-infected mice.

  17. Effects of heavy-ion irradiation on FeSe

    NASA Astrophysics Data System (ADS)

    Sun, Yue; Park, Akiyoshi; Pyon, Sunseng; Tamegai, Tsuyoshi; Kambara, Tadashi; Ichinose, Ataru

    2017-03-01

    We report the effects of heavy-ion irradiation on FeSe single crystals by irradiating uranium up to a dose-equivalent matching field of Bϕ=16 T. Almost continuous columnar defects along the c axis with a diameter of ˜10 nm are confirmed by high-resolution transmission electron microscopy. Tc is found to be suppressed by introducing columnar defects at a rate of d Tc/d Bϕ˜-0.29 K/T, which is much larger than those observed in iron pnictides. This unexpected large suppression of Tc in FeSe is discussed in relation to the large diameter of the columnar defects as well as its unique band structure with a remarkably small Fermi energy. The critical current density is first dramatically enhanced with irradiation reaching a value over ˜2 ×105A /cm2 (˜5 times larger than that of the pristine sample) at 2 K (self-field) with Bϕ=2 T, then gradually suppressed with increasing Bϕ. The δ l pinning associated with charge-carrier mean-free-path fluctuations and the δ Tc pinning associated with spatial fluctuations of the transition temperature are found to coexist in the pristine FeSe, while the irradiation increases the contribution from δ l pinning and makes it dominant over Bϕ=4 T.

  18. Suppression effects in feature-based attention

    PubMed Central

    Wang, Yixue; Miller, James; Liu, Taosheng

    2015-01-01

    Attending to a feature enhances visual processing of that feature, but it is less clear what occurs to unattended features. Single-unit recording studies in middle temporal (MT) have shown that neuronal modulation is a monotonic function of the difference between the attended and neuron's preferred direction. Such a relationship should predict a monotonic suppressive effect in psychophysical performance. However, past research on suppressive effects of feature-based attention has remained inconclusive. We investigated the suppressive effect for motion direction, orientation, and color in three experiments. We asked participants to detect a weak signal among noise and provided a partially valid feature cue to manipulate attention. We measured performance as a function of the offset between the cued and signal feature. We also included neutral trials where no feature cues were presented to provide a baseline measure of performance. Across three experiments, we consistently observed enhancement effects when the target feature and cued feature coincided and suppression effects when the target feature deviated from the cued feature. The exact profile of suppression was different across feature dimensions: Whereas the profile for direction exhibited a “rebound” effect, the profiles for orientation and color were monotonic. These results demonstrate that unattended features are suppressed during feature-based attention, but the exact suppression profile depends on the specific feature. Overall, the results are largely consistent with neurophysiological data and support the feature-similarity gain model of attention. PMID:26067533

  19. Immunity to herpes simplex virus type 2. Suppression of virus-induced immune responses in ultraviolet B-irradiated mice

    SciTech Connect

    Yasumoto, S.; Hayashi, Y.; Aurelian, L.

    1987-10-15

    Ultraviolet B irradiation (280 to 320 nm) of mice at the site of intradermal infection with herpes simplex virus type 2 increased the severity of the herpes simplex virus type 2 disease and decreased delayed-type hypersensitivity (DTH) responses to viral antigen. Decrease in DTH resulted from the induction of suppressor T cells, as evidenced by the ability of spleen cells from UV-irradiated mice to inhibit DTH and proliferative responses after adoptive transfer. Lymph node cells from UV-irradiated animals did not transfer suppression. DTH was suppressed at the induction but not the expression phase. Suppressor T cells were Lyt-1+, L3T4+, and their activity was antigen-specific. However, after in vitro culture of spleen cells from UV-irradiated mice with herpes simplex virus type 2 antigen, suppressor activity was mediated by Lyt-2+ cells. Culture supernatants contained soluble nonantigen-specific suppressive factors.

  20. Suppression of hepatocellular carcinoma cell proliferation by short hairpin RNA of frizzled 2 with Sonazoid-enhanced irradiation.

    PubMed

    Tomizawa, Minoru; Shinozaki, Fuminobu; Motoyoshi, Yasufumi; Sugiyama, Takao; Yamamoto, Shigenori; Ishige, Naoki

    2016-01-01

    Short-hairpin RNA of frizzled-2 (shRNA-Fz2) is known to suppress the proliferation of hepatocellular carcinoma (HCC) cells; however, its effect on HCC cell motility is unknown. In this study, suppression of HCC cell motility by shRNA-Fz2 was analyzed, and introduction of shRNA-Fz2 into HCC cells was facilitated with ultrasound (US) irradiation generated from a diagnostic US device, which was enhanced by the contrast-enhanced US reagent Sonazoid. The HCC cell lines HLF and PLC/PRF/5 that were transfected with shRNA-Fz2 were plated to form monolayers, following which the cell monolayers were scratched with a sterile razor. After 48 h, the cells were stained with hematoxylin and eosin, and the distance between the growing edge of the cell layer and the scratch lines was measured. Total RNA from the cells was isolated and subjected to real-time quantitative PCR to quantify matrix metalloproteinase 9 expression at 48 h after transfection of shRNA-Fz2. Starch-iodide method was applied to analyze the generation of H2O2 following US irradiation with the addition of Sonazoid in the liquid, and cell proliferation was analyzed 72 h later. The distances between the growing edge of the cell layer and the scratch lines and MMP9 expression levels were significantly decreased with transfection of shRNA-Fz2 (P<0.05). In the starch-iodide method, absorbance significantly decreased with the addition of Sonazoid (P<0.05), which suggested that US irradiation with Sonazoid generated H2O2 and enhanced sonoporation. ShRNA-Fz2 suppressed cell proliferation of both cell lines at a mechanical index of 0.4. Motility of HLF cells and PLC/PRF/5 cells was suppressed by shRNA-FZ2. Sonazoid enhanced sonoporation of the cells with the diagnostic US device and the suppression of proliferation of both HCC cell lines by shRNA-Fz2.

  1. Theory of suppressing avalanche process of carrier in short pulse laser irradiated dielectrics

    SciTech Connect

    Deng, H. X. E-mail: xtzu@uestc.edu.cn Zu, X. T. E-mail: xtzu@uestc.edu.cn Xiang, X.; Zheng, W. G.; Yuan, X. D.; Sun, K. E-mail: xtzu@uestc.edu.cn; Gao, F.

    2014-05-28

    A theory for controlling avalanche process of carrier during short pulse laser irradiation is proposed. We show that avalanche process of conduction band electrons (CBEs) is determined by the occupation number of phonons in dielectrics. The theory provides a way to suppress avalanche process and a direct judgment for the contribution of avalanche process and photon ionization process to the generation of CBEs. The obtained temperature dependent rate equation shows that the laser induced damage threshold of dielectrics, e.g., fused silica, increase nonlinearly with the decreases of temperature. Present theory predicts a new approach to improve the laser induced damage threshold of dielectrics.

  2. Irradiation spectrum and ionization-induced diffusion effects in ceramics

    SciTech Connect

    Zinkle, S.J.

    1997-08-01

    There are two main components to the irradiation spectrum which need to be considered in radiation effects studies on nonmetals, namely the primary knock-on atom energy spectrum and ionizing radiation. The published low-temperature studies on Al{sub 2}O{sub 3} and MgO suggest that the defect production is nearly independent of the average primary knock-on atom energy, in sharp contrast to the situation for metals. On the other hand, ionizing radiation has been shown to exert a pronounced influence on the microstructural evolution of both semiconductors and insulators under certain conditions. Recent work on the microstructure of ion-irradiated ceramics is summarized, which provides evidence for significant ionization-induced diffusion. Polycrystalline samples of MgO, Al{sub 2}O{sub 3}, and MgAl{sub 2}O{sub 4} were irradiated with various ions ranging from 1 MeV H{sup +} to 4 MeV Zr{sup +} ions at temperatures between 25 and 650{degrees}C. Cross-section transmission electron microscopy was used to investigate the depth-dependent microstructural of the irradiated specimens. Dislocation loop nucleation was effectively suppressed in specimens irradiated with light ions, whereas the growth rate of dislocation loops was enhanced. The sensitivity to irradiation spectrum is attributed to ionization-induced diffusion. The interstitial migration energies in MgAl{sub 2}O{sub 4} and Al{sub 2}O{sub 3} are estimated to be {le}0.4 eV and {le}0.8 eV, respectively for irradiation conditions where ionization-induced diffusion effects are expected to be negligible.

  3. Mechanism of immune suppression by ultraviolet irradiation in vivo. I. Evidence for the existence of a unique photoreceptor in skin and its role in photoimmunology

    SciTech Connect

    De Fabo, E.C.; Noonan, F.P.

    1983-07-01

    UV irradiation of mice causes a systemic immune alteration that can be detected either by suppression of the immunologic rejection of UV-induced tumors, or by suppression of contact hypersensitivity (CHS). Suppression of these two immunologic responses has similar photobiologic characteristics and in both cases is associated with the generation of antigen-specific suppressor T cells. To identify whether a specific photoreceptor for this effect exists, the relative wavelength effectiveness (action spectrum) was determined for the UV-induced suppression of CHS. Narrow bands of UV (half bandwidth 3 nm) were used at 10 wavelengths from 250 to 320 nm to obtain dose-response curves. The action spectrum derived from the dose-response curves has a maximum between 260 and 270 nm, a shoulder at 280-290 nm, and declines steadily to approximately 3% of maximum at 320 nm. The finding of such a clearly defined wavelength dependence implies the presence of a specific photoreceptor for this effect. Removing the stratum corneum by tape stripping before UV irradiation prevented the suppression of CHS using 254-nm radiation, suggesting the photoreceptor is superficially located in the skin. The hypothesis is advanced that the photoreceptor for systemic UV-induced immunosuppression of contact hypersensitivity may be urocanic acid. As such, it may also play a role in UV-induced carcinogenesis via the production of tumor-specific suppressor cells.

  4. Effect of Laser Irradiation on Enzyme Activity

    NASA Astrophysics Data System (ADS)

    Murakami, Satoshi; Kashii, Masafumi; Kitano, Hiroshi; Adachi, Hiroaki; Takano, Kazufumi; Matsumura, Hiroyoshi; Inoue, Tsuyoshi; Mori, Yusuke; Doi, Masaaki; Sugamoto, Kazuomi; Yoshikawa, Hideki; Sasaki, Takatomo

    2005-11-01

    We previously developed a protein crystallization technique using a femtosecond laser and protein crystal processing and detaching techniques using a pulsed UV laser. In this study, we examine the effect of laser irradiation on protein integrity. After several kinds of laser were irradiated on part of a solution of glycerol-6-phosphate dehydrogenase from Leuconostoc mesenteroides, we measured the enzyme activity. Femtosecond and deep-UV laser irradiations have little influence on the whole enzyme activity, whereas the enzyme lost its activity upon high-power near-infrared laser irradiation at a wavelength of 1547 nm. These results suggest that suitable laser irradiation has no remarkable destructive influence on protein crystallization or crystal processing.

  5. Treatment of NZB/NZW mice with total lymphoid irradiation: long-lasting suppression of disease without generalized immune suppression

    SciTech Connect

    Kotzin, B.L.; Arndt, R.; Okada, S.; Ward, R.; Thach, A.B.; Strober, S.

    1986-05-01

    We used total lymphoid irradiation (TLI; total dose = 3400 rad) to treat the lupus-like renal disease of 6-mo-old female NZB/NZW mice. Similar to our past studies, this treatment resulted in a marked prolongation of survival, decrease in proteinuria, and decrease in serum anti-DNA antibodies compared with untreated littermate controls. Although there was no evidence of disease recurrence in TLI-treated mice until after 12 mo of age, the in vitro proliferative response to phytohemagglutinin by NZB/NZW spleen cells recovered within 6 wk such that responses were greater than control NZB/NZW animals. A similar recovery and overshoot after TLI were evident in the primary antibody response to the T cell-dependent antigen sheep red blood cells (SRBC). Both the total and IgG anti-SRBC antibody responses after TLI were greater than those of untreated NZB/NZW controls, and were comparable with those of untreated non-autoimmune mice. Despite this increased response to mitogens and antigens after TLI, we noted a decrease in spontaneous splenic IgG-secreting cells and a decrease in IgG but not IgM antinuclear antibody production. Nonspecific suppressor cells of the mixed leukocyte response were detectable in the spleens of NZB/NZW mice early after TLI. However, the disappearance of suppressor cells was not associated with recrudescence of disease activity. Furthermore, transfer of large numbers of spleen cells from TLI-treated NZB/NZW mice did not result in disease suppression in untreated age-matched recipients. In summary, treatment of NZB/NZW mice with TLI results in a prolonged remission in autoimmune disease, which is achieved in the absence of generalized immunosuppression.

  6. White Light Demonstration of One Hundred Parts per Billion Irradiance Suppression in Air by New Starshade Occulters

    NASA Technical Reports Server (NTRS)

    Levinton, Douglas B.; Cash, Webster C.; Gleason, Brian; Kaiser, Michael J.; Levine, Sara A.; Lo, Amy S.; Schindhelm, Eric; Shipley, Ann F.

    2007-01-01

    A new mission concept for the direct imaging of exo-solar planets called the New Worlds Observer (NWO) has been proposed. The concept involves flying a meter-class space telescope in formation with a newly-conceived, specially-shaped, deployable star-occulting shade several meters across at a separation of some tens of thousands of kilometers. The telescope would make its observations from behind the starshade in a volume of high suppression of incident irradiance from the star around which planets orbit. The required level of irradiance suppression created by the starshade for an efficacious mission is of order 0.1 to 10 parts per billion in broadband light. This paper discusses the experimental setup developed to accurately measure the suppression ratio of irradiance produced at the null position behind candidate starshade forms to these levels. It also presents results of broadband measurements which demonstrated suppression levels of just under 100 parts per billion in air using the Sun as a light source. Analytical modeling of spatial irradiance distributions surrounding the null are presented and compared with photographs of irradiance captured in situ behind candidate starshades.

  7. Studies of Transport Properties and Critical Temperature Suppression Mechanism in Yttrium BARIUM(2) COPPER(3) Oxygen(x) Thin Films Irradiated with 20 TO 120 KEV Electrons

    NASA Astrophysics Data System (ADS)

    Lin, Jiunn-Yuan

    1995-11-01

    We present comprehensive studies of the effects of 20 to 120 keV electron irradiation on rm YBa_2Cu_3O_{x} thin films. Above 60 keV, T_{c } of irradiated samples is suppressed accompanied by a significant increase in residual resistivity, while the carrier concentration remains relatively unchanged. The plane oxygen defects produced by irradiation are found to be responsible for T_{c} suppression. The II suppression mechanism is discussed within several theoretical frameworks. Though in qualitative agreement with d-wave pairing symmetry, our results show a T_{c} suppression rate three times as slow as predicted by the theory when resistivity data are used to extract the impurity scattering rate. Alternatively, phase fluctuations theory gives a qualitative description as well. The displacement energy of plane oxygen is found to be 8.3 eV, which corresponds to a threshold electron energy 58 keV. Finally, an empirical relation is proposed to describe the temperature dependence of the Hall coefficient.

  8. Hormone Suppression with GnRH Antagonist Promotes Spermatogenic Recovery from Transplanted Spermatogonial Stem Cells in Irradiated Cynomolgus Monkeys

    PubMed Central

    Shetty, Gunapala; Uthamanthil, Rajesh K.; Zhou, Wei; Shao, Shan H.; Weng, Connie C.; Tailor, Ramesh C.; Hermann, Brian P.; Orwig, Kyle E.; Meistrich, Marvin L.

    2013-01-01

    SUMMARY Hormone suppression given before or after cytotoxic treatment stimulates recovery of spermatogenesis from endogenous and transplanted spermatogonial stem cells (SSC) and restores fertility in rodents. To test whether the combination of hormone suppression and transplantation could enhance the recovery of spermatogenesis in primates, we irradiated (7 Gy) the testes of 12 adult cynomolgus monkeys and treated 6 of them with GnRH-antagonist (GnRH-ant) for 8 weeks. At the end of this treatment, we transfected cryopreserved testicular cells with GFP-lentivirus and autologously transplanted them back into one of the testes. The only significant effect of GnRH-ant treatment on endogenous spermatogenesis was an increase in the percentage of tubules containing differentiated germ cells (tubule differentiation index; TDI) in the sham-transplanted testes of GnRH-ant-treated monkeys compared to radiation-only monkeys at 24 weeks after irradiation. Although transplantation alone after irradiation did not significantly increase the TDI, detection of lentiviral DNA in the sperm of one radiation-only monkey indicated that some transplanted cells colonized the testis. However, the combination of transplantation and GnRH-ant clearly stimulated spermatogenic recovery as evidenced by several observations in the GnRH-ant-treated monkeys receiving transplantation: (a) significant increases (~20%) in the volume and weight of the testes compared to the contralateral sham-transplanted testes and/or to the transplanted testes of the radiation-only monkeys; (b) increases in TDI compared to the transplanted testes of radiation-only monkeys at 24 weeks (9.6% vs. 2.9%; P=0.05) and 44 weeks (16.5% vs. 6.1%, P=0.055); (c) detection of lentiviral sequences in the sperm or testes of five of the GnRH-ant–treated monkeys; and (d) significantly higher sperm counts than in the radiation-only monkeys. Thus hormone suppression enhances spermatogenic recovery from transplanted SSC in primates and

  9. Effects of X‑ray irradiation in combination with ascorbic acid on tumor control.

    PubMed

    Hosokawa, Yoichiro; Monzen, Satoru; Yoshino, Hironori; Terashima, Shingo; Nakano, Manabu; Toshima, Keisuke; Saga, Ryo; Kashiwakura, Ikuo

    2015-10-01

    Our previous studies demonstrated that the combination of treatment with ascorbic acid (AsA) and X‑ray irradiation results in increased apoptosis in HL60 cells. The present study was performed to investigate the effects of the combined use of AsA and X‑ray irradiation on epithelial cancer and sarcoma cells, and its potential use in future clinical treatment. X‑ray irradiation combined with AsA treatment resulted in increased suppression of cell growth of HT1080, SAS and A549 cells in vitro compared with X‑ray irradiation alone. The combined treatment also suppressed tumor growth in implanted HT‑1080 cells in vivo. Using annexin V/propidium iodide staining and the detection of activated caspase 3, it was found that X‑ray irradiation increased the apoptotic rate of HT1080 cells and resulted in G2/M arrest. However, apoptosis in the HT1080 cells treated with 5 mM AsA remained unchanged, and no changes were observed in the G2/M fraction. By contrast, AsA treatment caused increased suppression of proliferation compared with X‑ray irradiation. These results suggested that 5 mM AsA slowed the cell cycle and reduced tumor growth. Therefore, X‑ray irradiation combined with AsA treatment may be effective against epithelial cancer and sarcoma cells.

  10. Enhanced suppression of tumor growth using a combination of NK4 plasmid DNA-PEG engrafted cationized dextran complex and ultrasound irradiation.

    PubMed

    Hosseinkhani, H; Kushibiki, T; Matsumoto, K; Nakamura, T; Tabata, Y

    2006-05-01

    This investigation aims to determine experimentally whether or not ultrasound (US) irradiation is effective in enhancing the in vivo gene expression of NK4 plasmid DNA and suppressing tumor growth. NK4, composed of the NH2-terminal hairpin and subsequent four-kringle domains of hepatocyte growth factor (HGF), acts as an HGF-antagonist and angiogenesis inhibitor. Dextran was cationized by introducing spermine to the hydroxyl groups to allow for polyionic complexation with NK4 plasmid DNA. The cationized dextran was additionally modified with poly(ethylene glycol) (PEG) molecules giving PEG engrafted cationized dextran. Significant suppression of tumor growth was observed when PEG engrafted cationized dextran-NK4 plasmid DNA complexes were intravenously injected into mice carrying a subcutaneous Lewis lung carcinoma tumor mass with subsequent US irradiation when compared with the cationized dextran-NK4 plasmid DNA complex and naked NK4 plasmid DNA with or without US irradiation. We conclude that complexation with PEG-engrafted cationized dextran in combination with US irradiation is a promising way to target the NK4 plasmid DNA to the tumor for gene expression.

  11. Analysis of Chromosomal Aberrations after Low and High Dose Rate Gamma Irradiation in ATM or NBS Suppressed Human Fibroblast Cells

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

    A detailed understanding of the biological effects of heavy nuclei is needed for space radiation protection and for cancer therapy. High-LET radiation produces more complex DNA lesions that may be non-repairable or that may require additional processing steps compared to endogenous DSBs, increasing the possibility of misrepair. Interplay between radiation sensitivity, dose, and radiation quality has not been studied extensively. Previously we studied chromosome aberrations induced by low- and high- LET radiation in several cell lines deficient in ATM (ataxia telangactasia 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. We found that the yields of both simple and complex chromosomal aberrations were significantly increased in the DSB repair defective cells compared to normal cells. The increased aberrations observed for the ATM and NBS defective lines was due to a significantly larger quadratic dose-response term compared to normal fibroblasts for both simple and complex aberrations, while the linear dose-response term was significantly higher in NBS cells only for simple exchanges. These results point to the importance of the functions of ATM and NBS in chromatin modifications that function to facilitate correct DSB repair and minimize aberration formation. To further understand the sensitivity differences that were observed in ATM and NBS deficient cells, in this study, chromosomal aberration analysis was performed in normal lung fibroblast cells treated with KU-55933, a specific ATM kinase inhibitor, or Mirin, an MRN complex inhibitor involved in activation of ATM. We are also testing siRNA knockdown of these proteins. Normal and ATM or NBS suppressed cells were irradiated with gamma-rays and chromosomes were collected with a premature chromosome

  12. Effect of weighting on time sidelobe suppression

    NASA Technical Reports Server (NTRS)

    Dicenzo, A.

    1978-01-01

    Weighting simulations in the time domain were considered to shape the time-compressed pulse waveform. The digital input radar data were 32 bit I,Q, and simulated data from a point target, imaged by a Seasat-A type system. Weighting functions tested include stepped-amplitude distributions, (with 1 through 5 steps), and the cosine-squared plus pedestal distribution. Effects treated include mainlobe ratio, signal to noise ratio, and nearest sidelobe suppression.

  13. The volume effect in irradiated mouse colorectum

    NASA Astrophysics Data System (ADS)

    Skwarchuk, Mark William

    1997-11-01

    Damage of the colorectum is the dose-limiting normal tissue complication following radiotherapy of prostate and cervical cancers. One approach for decreasing complications is to physically reduce the treatment volume. Mathematical models have been previously developed to describe the change in associated toxicity with a change in irradiated volume, i.e. the 'volume effect', for serial-type normal tissues including the colorectum. The first goal of this thesis was to test the hypothesis that there would not be a threshold length in the development of obstruction after irradiation of mouse colorectum, as predicted by the Probability model of the volume effect. The second goal was to examine if there were differences in the threshold and in the incidence of colorectal obstruction after irradiation of two mouse strains, C57B1/6 (C57) and C3Hf/Kam (C3H), previously found to be fibrosis-prone and-resistant, respectively, after lung irradiation due, in part, to genetic differences. The hypothesis examined was that differences in incidence between strains were due to the differential expression of the fibrogenic cytokines TGF/beta and TNF/alpha. Various lengths of C57 and C3H mouse colorectum were irradiated and the incidence of colorectal obstruction was followed up to 15 months. A threshold length was observed for both mouse strains, in contradiction of model predictions. The mechanism of the threshold was epithelial regeneration after irradiation. C57 mice had significantly higher incidence of colorectal obstruction compared to C3H mice, especially at smaller irradiated lengths. Colorectal tissue was obtained at various times after irradiation and prepared for histology, immunohistochemistry and RNase protection assay for measurement of TGF/beta 1, 2, 3 and TNF/alpha mRNA. Distinct strain differences in the histological time of appearance and spatial locations of fibrosis were observed. However, there were no consistent strain difference in mRNA levels or

  14. Simultaneous irradiation with different wavelengths of ultraviolet light has synergistic bactericidal effect on Vibrio parahaemolyticus.

    PubMed

    Nakahashi, Mutsumi; Mawatari, Kazuaki; Hirata, Akiko; Maetani, Miki; Shimohata, Takaaki; Uebanso, Takashi; Hamada, Yasuhiro; Akutagawa, Masatake; Kinouchi, Yousuke; Takahashi, Akira

    2014-01-01

    Ultraviolet (UV) irradiation is an increasingly used method of water disinfection. UV rays can be classified by wavelength into UVA (320-400 nm), UVB (280-320 nm), and UVC (<280 nm). We previously developed UVA sterilization equipment with a UVA light-emitting diode (LED). The aim of this study was to establish a new water disinfection procedure using the combined irradiation of the UVA-LED and another UV wavelength. An oxidative DNA product, 8-hydroxy-2'-deoxyguanosine (8-OHdG), increased after irradiation by UVA-LED alone, and the level of cyclobutane pyrimidine dimers (CPDs) was increased by UVC alone in Vibrio parahaemolyticus. Although sequential irradiation of UVA-LED and UVC-induced additional bactericidal effects, simultaneous irradiation with UVA-LED and UVC-induced bactericidal synergistic effects. The 8-OHdG and CPDs production showed no differences between sequential and simultaneous irradiation. Interestingly, the recovery of CPDs was delayed by simultaneous irradiation. The synergistic effect was absent in SOS response-deficient mutants, such as the recA and lexA strains. Because recA- and lexA-mediated SOS responses have crucial roles in a DNA repair pathway, the synergistic bactericidal effect produced by the simultaneous irradiation could depend on the suppression of the CPDs repair. The simultaneous irradiation of UVA-LED and UVC is a candidate new procedure for effective water disinfection.

  15. Effects of irradiation on platelet function

    SciTech Connect

    Rock, G.; Adams, G.A.; Labow, R.S.

    1988-09-01

    Current medical practice involves the irradiation of blood components, including platelet concentrates, before their administration to patients with severe immunosuppression. The authors studied the effect of irradiation on in vitro platelet function and the leaching of plasticizers from the bag, both immediately and after 5 days of storage. The platelet count, white cell count, pH, glucose, lactate, platelet aggregation and release reaction, and serotonin uptake were not altered by the irradiation of random-donor or apheresis units with 2000 rads carried out at 0 and 24 hours and 5 days after collection. The leaching of di(2-ethylhexyl)phthalate from the plastic bags followed by the conversion to mono(2-ethylhexyl)phthalate was not increased by irradiation. Therefore, it is possible to irradiate platelet concentrates on the day of collection and subsequently store them for at least 5 days while maintaining in vitro function. This procedure could have considerable benefit for blood banks involved in the provision of many platelet products.

  16. Ion irradiation effects on metallic nanocrystals

    SciTech Connect

    Kluth, P.; Johannessen, B.; Giulian, R.; Schnohr, C.S.; Foran, G.J.; Cookson, D.J.; Byrne, A.P.; Ridgway, M.C.

    2008-04-02

    We have investigated structural and morphological properties of metallic nanocrystals (NCs) exposed to ion irradiation. NCs were characterized by transmission electron microscopy in combination with advanced synchrotron-based analytical techniques, in particular X-ray absorption spectroscopy and small-angle X-ray scattering. A number of different effects were observed depending on the irradiation conditions. At energies where nuclear stopping is predominant, structural disorder/amorphization followed by inverse Ostwald ripening/dissolution due to ion beam mixing was observed for Au and Cu NCs embedded in SiO{sub 2}. The ion-irradiation-induced crystalline to amorphous transition in the NCs, which cannot be achieved in the corresponding bulk metals, was attributed to their initially higher structural energy as compared to bulk material and possibly preferential nucleation of the amorphous phase at the NC/SiO{sub 2} interface. At very high irradiation energies (swift heavy ion irradiation), where the energy loss is nearly entirely due to electronic stopping, a size-dependent shape transformation of the NCs from spheres to rod like shapes was apparent in Au NCs. Our preliminary results are in good agreement with considerations on melting of the NCs in the ion track as one mechanism involved in the shape transformation.

  17. Effects of laser irradiation on a bloom forming cyanobacterium Microcystis aeruginosa.

    PubMed

    Li, Tiancui; Bi, Yonghong; Liu, Jiantong; Wu, Chenxi

    2016-10-01

    Effects of laser irradiation on photosystem II (PS II) photochemical efficiencies, growth, and other physiological responses of Microcystis aeruginosa were investigated in this study. Results indicate that laser irradiation (wavelengths 405, 450, 532, and 650 nm) could effectively inhibit maximal PS II quantum yield (Fv/Fm) and maximal electron transport rates (ETRmax) of M. aeruginosa, while saturating light levels (Ek) of M. aeruginosa did not change significantly. Among the four tested wavelengths, 650 nm laser (red light) showed the highest inhibitory efficiency. Following 650 nm laser irradiation, the growth of M. aeruginosa was significantly suppressed, and contents of cellular photosynthetic pigments (chlorophyll a, carotenoid, phycocyanin, and allophycocyanin) decreased as irradiation dose increased. Meanwhile, laser irradiation enhanced the enzyme activities of superoxide dismutase (SOD) and peroxidase (POD) in M. aeruginosa cells. Lower irradiation doses did not change the intracellular microcystin contents, but higher dose irradiation (>1284 J cm(-2)) caused the release of microcystin into the culture medium. Transmission electron microscope examination showed that the ultrastructure of M. aeruginosa cells was destructed progressively following laser irradiation. Effects of laser irradiation on M. aeruginosa may be a combination of photochemical, electromagnetic, and thermal effects.

  18. Conditionals, Context, and the Suppression Effect.

    PubMed

    Cariani, Fabrizio; Rips, Lance J

    2016-02-01

    Modus ponens is the argument from premises of the form If A, then B and A to the conclusion B (e.g., from If it rained, Alicia got wet and It rained to Alicia got wet). Nearly all participants agree that the modus ponens conclusion logically follows when the argument appears in this Basic form. However, adding a further premise (e.g., If she forgot her umbrella, Alicia got wet) can lower participants' rate of agreement-an effect called suppression. We propose a theory of suppression that draws on contemporary ideas about conditional sentences in linguistics and philosophy. Semantically, the theory assumes that people interpret an indicative conditional as a context-sensitive strict conditional: true if and only if its consequent is true in each of a contextually determined set of situations in which its antecedent is true. Pragmatically, the theory claims that context changes in response to new assertions, including new conditional premises. Thus, the conclusion of a modus ponens argument may no longer be accepted in the changed context. Psychologically, the theory describes people as capable of reasoning about broad classes of possible situations, ordered by typicality, without having to reason about individual possible worlds. The theory accounts for the main suppression phenomena, and it generates some novel predictions that new experiments confirm.

  19. Differences in the effects of host suppression on the adoptive immunotherapy of subcutaneous and visceral tumors

    SciTech Connect

    Chang, A.E.; Shu, S.Y.; Chou, T.; Lafreniere, R.; Rosenberg, S.A.

    1986-07-01

    A syngeneic transplantable sarcoma induced in C57BL/6 mice, MCA 105, was used in studies to examine host suppression on the adoptive immunotherapy of established intradermal and experimentally induced pulmonary and hepatic metastases. Fresh immune splenocytes were generated from mice immunized to the MCA 105 tumor by a mixture of viable tumor cells and Corynebacterium parvum. The adoptive immunotherapy of intradermal MCA 105 tumor with immune cells required prior immunosuppression of the recipient by sublethal irradiation with 500 R or T-cell depletion. The effect of whole-body sublethal irradiation appeared to eliminate a systemic host suppression mechanism, since partialbody irradiation involving the tumor-bearing area did not permit successful immunotherapy. Host irradiation was not required to achieve successful immunotherapy of experimentally induced pulmonary or hepatic metastases. In nonirradiated recipients bearing both intradermal and pulmonary tumors, host suppression did not affect the function of transferred immune cells to induce regression of pulmonary metastases. Thus, suppression of adoptive immunotherapy appears to be relevant to tumors confined to the skin and subcutaneous tissue but not to tumor in visceral sites, such as the lung and liver.

  20. Irradiation with narrowband-ultraviolet B suppresses phorbol ester-induced up-regulation of H1 receptor mRNA in HeLa cells.

    PubMed

    Kitamura, Yoshiaki; Mizuguchi, Hiroyuki; Okamoto, Kentaro; Kitayama, Mika; Fujii, Tatsuya; Fujioka, Akira; Matsushita, Toshio; Mukai, Takashi; Kubo, Yoshiaki; Kubo, Nobuo; Fukui, Hiroyuki; Takeda, Noriaki

    2016-01-01

    Conclusion These findings suggest that low dose irradiation with 310 nm NB-UVB specifically suppressed the up-regulation of H1R gene expression without inducing apoptosis and that UVB of shorter or longer wavelength than 310 nm NB-UVB had no such effects. Objective To develop a narrowband-ultraviolet B(NB-UVB) phototherapy for allergic rhinitis, this study investigated the effects of irradiation with NB-UVB at wavelength of 310 nm on phorbol-12-myristate-13-acetate (PMA)-induced up-regulation of histamine H1 receptor (H1R) mRNA in HeLa cells. Methods The mRNA levels of H1R in HeLa cells were measured using real-time RT-PCR. Apoptosis were evaluated with DNA fragmentation assay. Results PMA induced a significant increase in H1R mRNA expression in HeLa cells. Irradiation with 305 nm UVB and 310 nm NB-UVB, but not with 315 nm UVB at doses of 200 and 300 mJ/cm(2) significantly suppressed PMA-induced up-regulation of H1R mRNA. At a dose of 200 mJ/cm(2), irradiation with 305 nm UVB, but not with 310 nm NB-UVB, induced apoptosis, although exposure of the cells to both 305 and 310 nm UVB induced apoptosis at a dose of 300 mJ/cm(2) after PMA treatment in HeLa cells. Conversely, irradiation with 315 nm UVB at doses of 200 and 300 mJ/cm(2) did not induce apoptosis.

  1. Effects of gamma irradiation on deteriorated paper

    NASA Astrophysics Data System (ADS)

    Bicchieri, Marina; Monti, Michela; Piantanida, Giovanna; Sodo, Armida

    2016-08-01

    Even though gamma radiation application, also at the minimum dosage required for disinfection, causes depolymerization and degradation of the paper substrate, recently published papers seemed, instead, to suggest that γ-rays application could be envisaged in some conditions for Cultural Heritage original documents and books. In some of the published papers, the possible application of γ-rays was evaluated mainly by using mechanical tests that scarcely reflect the chemical modifications induced in the cellulosic support. In the present article the effect of low dosage γ-irradiation on cellulosic substrates was studied and monitored applying different techniques: colorimetry, spectroscopic measurements, carbonyl content and average viscometric degree of polymerization. Two different papers were investigated, a non-sized, non-filled cotton paper, and a commercial permanent paper. To simulate a real deteriorated document, which could need γ-rays irradiation, some samples were submitted to a hydrolysis treatment. We developed a treatment based on the exposition of paper to hydrochloric acid vapors, avoiding any contact of the samples with water. This method induces a degradation similar to that observed on original documents. The samples were then irradiated with 3 kGy γ-rays at a 5258 Gy/h rate. The aforementioned analyses were performed on the samples just irradiated and after artificial ageing. All tests showed negative effects of gamma irradiation on paper. Non-irradiated paper preserves better its appearance and chemical properties both in the short term and after ageing, while the irradiated samples show appreciable color change and higher oxidation extent. Since the Istituto centrale restauro e conservazione patrimonio archivistico e librario is responsible for the choice of all restoration treatments that could be applied on library and archival materials under the protection of the Italian State (http://www.icpal.beniculturali.it/allegati/DM-7

  2. Changes in cluster magnetism and suppression of local superconductivity in amorphous FeCrB alloy irradiated by Ar+ ions

    NASA Astrophysics Data System (ADS)

    Okunev, V. D.; Samoilenko, Z. A.; Szymczak, H.; Szewczyk, A.; Szymczak, R.; Lewandowski, S. J.; Aleshkevych, P.; Malinowski, A.; Gierłowski, P.; Więckowski, J.; Wolny-Marszałek, M.; Jeżabek, M.; Varyukhin, V. N.; Antoshina, I. A.

    2016-02-01

    We show that сluster magnetism in ferromagnetic amorphous Fe67Cr18B15 alloy is related to the presence of large, D=150-250 Å, α-(Fe Cr) clusters responsible for basic changes in cluster magnetism, small, D=30-100 Å, α-(Fe, Cr) and Fe3B clusters and subcluster atomic α-(Fe, Cr, B) groupings, D=10-20 Å, in disordered intercluster medium. For initial sample and irradiated one (Φ=1.5×1018 ions/cm2) superconductivity exists in the cluster shells of metallic α-(Fe, Cr) phase where ferromagnetism of iron is counterbalanced by antiferromagnetism of chromium. At Φ=3×1018 ions/cm2, the internal stresses intensify and the process of iron and chromium phase separation, favorable for mesoscopic superconductivity, changes for inverse one promoting more homogeneous distribution of iron and chromium in the clusters as well as gigantic (twice as much) increase in density of the samples. As a result, in the cluster shells ferromagnetism is restored leading to the increase in magnetization of the sample and suppression of local superconductivity. For initial samples, the temperature dependence of resistivity ρ(T) T2 is determined by the electron scattering on quantum defects. In strongly inhomogeneous samples, after irradiation by fluence Φ=1.5×1018 ions/cm2, the transition to a dependence ρ(T) T1/2 is caused by the effects of weak localization. In more homogeneous samples, at Φ=3×1018 ions/cm2, a return to the dependence ρ(T) T2 is observed.

  3. Effects of tic suppression: ability to suppress, rebound, negative reinforcement, and habituation to the premonitory urge.

    PubMed

    Specht, Matt W; Woods, Douglas W; Nicotra, Cassandra M; Kelly, Laura M; Ricketts, Emily J; Conelea, Christine A; Grados, Marco A; Ostrander, Rick S; Walkup, John T

    2013-01-01

    The comprehensive behavioral intervention for tics (CBIT) represents a safe, effective non-pharmacological treatment for Tourette's disorder that remains underutilized as a treatment option. Contributing factors include the perceived negative consequences of tic suppression and the lack of a means through which suppression results in symptom improvement. Participants (n = 12) included youth ages 10-17 years with moderate-to-marked tic severity and noticeable premonitory urges who met Tourette's or chronic tic disorder criteria. Tic frequency and urge rating data were collected during an alternating sequence of tic freely or reinforced tic suppression periods. Even without specific instructions regarding how to suppress tics, youth experienced a significant, robust (72%), stable reduction in tic frequency under extended periods (40 min) of contingently reinforced tic suppression in contrast to periods of time when tics were ignored. Following periods of prolonged suppression, tic frequency returned to pre-suppression levels. Urge ratings did not show the expected increase during the initial periods of tic suppression, nor a subsequent decline in urge ratings during prolonged, effective tic suppression. Results suggest that environments conducive to tic suppression result in reduced tic frequency without adverse consequences. Additionally, premonitory urges, underrepresented in the literature, may represent an important enduring etiological consideration in the development and maintenance of tic disorders.

  4. Long-term effects of orbital irradiation

    SciTech Connect

    Guyuron, B.; Dagys, A.P.; Munro, I.R.

    1987-11-01

    This retrospective study is a review of 18 patients who received radiotherapy to the orbit between the ages of 1 month and 10 years. Patients were followed for 7-21 years in an attempt to define the effects of orbital irradiation on a growing child. None of the patients in the study was spared injurious effects on soft tissue or bone, but soft tissue appeared to be more vulnerable to radiation than bone. Orbital irradiation caused soft tissue deficits of the upper face in 100% of the patients. Sixty-seven percent of patients had soft tissue deformities of the midface, and 13% had soft tissue deformities of the lower face. Bony deficits were found in the upper face in 67% of the patients, the midface in 50%, and the lower face in 6%. This study found no correlation between age and time of radiotherapy on the effects of facial growth.

  5. Quantification of biologically effective environmental UV irradiance

    NASA Astrophysics Data System (ADS)

    Horneck, G.

    To determine the impact of environmental UV radiation on human health and ecosystems demands monitoring systems that weight the spectral irradiance according to the biological responses under consideration. In general, there are three different approaches to quantify a biologically effective solar irradiance: (i) weighted spectroradiometry where the biologically weighted radiometric quantities are derived from spectral data by multiplication with an action spectrum of a relevant photobiological reaction, e.g. erythema, DNA damage, skin cancer, reduced productivity of terrestrial plants and aquatic foodweb; (ii) wavelength integrating chemical-based or physical dosimetric systems with spectral sensitivities similar to a biological response curve; and (iii) biological dosimeters that directly weight the incident UV components of sunlight in relation to the effectiveness of the different wavelengths and to interactions between them. Most biological dosimeters, such as bacteria, bacteriophages, or biomolecules, are based on the UV sensitivity of DNA. If precisely characterized, biological dosimeters are applicable as field and personal dosimeters.

  6. Suppressive effects of ketamine on macrophage functions

    SciTech Connect

    Chang Yi; Chen, T.-L.; Sheu, J.-R.; Chen, R.-M. . E-mail: rmchen@tmu.edu.tw

    2005-04-01

    Ketamine is an intravenous anesthetic agent. Clinically, induction of anesthesia with ketamine can cause immunosuppression. Macrophages play important roles in host defense. In this study, we attempted to evaluate the effects of ketamine on macrophage functions and its possible mechanism using mouse macrophage-like Raw 264.7 cells as the experimental model. Exposure of macrophages to 10 and 100 {mu}M ketamine, which correspond to 0.1 and 1 times the clinically relevant concentration, for 1, 6, and 24 h had no effect on cell viability or lactate dehydrogenase release. When the administered concentration reached 1000 {mu}M, ketamine caused a release of lactate dehydrogenase and cell death. Ketamine, at 10 and 100 {mu}M, did not affect the chemotactic activity of macrophages. Administration of 1000 {mu}M ketamine in macrophages resulted in a decrease in cell migration. Treatment of macrophages with ketamine reduced phagocytic activities. The oxidative ability of macrophages was suppressed by ketamine. Treatment with lipopolysaccharide induced TNF-{alpha}, IL-1{beta}, and IL-6 mRNA in macrophages. Administration of ketamine alone did not influence TNF-{alpha}, IL-1{beta}, or IL-6 mRNA production. Meanwhile, cotreatment with ketamine and lipopolysaccharide significantly inhibited lipopolysaccharide-induced TNF-{alpha}, IL-1{beta}, and IL-6 mRNA levels. Exposure to ketamine led to a decrease in the mitochondrial membrane potential. However, the activity of mitochondrial complex I NADH dehydrogenase was not affected by ketamine. This study shows that a clinically relevant concentration of ketamine (100 {mu}M) can suppress macrophage function of phagocytosis, its oxidative ability, and inflammatory cytokine production possibly via reduction of the mitochondrial membrane potential instead of direct cellular toxicity.

  7. IRRADIATION EFFECTS ON THE PHYSICAL CHARACTERISTICS OF SEWAGE SLUDGE

    SciTech Connect

    Lee, M-J.; Lee, J-K.; Yoo, D-H.; Ho, K.

    2004-10-05

    The radiation effects on the physical characteristic of the sewage sludge were studied in order to obtain information which will be used for study on the enhancement of the sludge's dewaterability. Water contents, capillary suction time, zeta potential, irradiation dose, sludge acidity, total solid concentration, sludge particle size and microbiology before and after irradiation were investigated. Irradiation gave an effect on physical characteristics sludge. Water content in sludge cake could be reduced by irradiation at the dose of 10kGy.

  8. The effect of gamma irradiation on injectable human amnion collagen

    SciTech Connect

    Liu, B.C.; Harrell, R.; Davis, R.H.; Dresden, M.H.; Spira, M. )

    1989-08-01

    The effect of gamma irradiation on the physicochemical properties of injectable human amnion collagen was investigated. Pepsin-extracted human amnion collagen was purified, reconstituted, and irradiated with varying doses of gamma irradiation (0.25 Mrads to 2.5 Mrads). Gamma irradiation had a significant impact on the physical characteristics of the collagen. The neutral solubility of collagen in PBS at 45{degrees}C was decreased from 100% for the nonirradiated control sample to 16% for the 2.5 Mrads irradiated sample. SDS polyacrylamide gel electrophoresis also demonstrated the dose-dependent effect of gamma irradiation on collagen cross-links. Electron microscopic observation revealed that even at low irradiation dose (0.25 Mrads), collagen fibril diameter increased. The average diameter was 50 nm for nonirradiated control fibrils, while 4.4% of the irradiated collagen fibrils had a diameter greater than 100 nm. Irradiated collagen showed little evidence of damage. Well-preserved cross-striations were found in collagen fibrils at all doses of irradiation. Native amnion collagen irradiated with gamma rays demonstrated a slight increase in resistance to collagenase degradation compared with nonirradiated native collagen samples. Increased resistance to collagenase did not correlate with increasing irradiation dose. After 30 min of incubation at 37{degrees}C, both irradiated and nonirradiated collagen was completely digested by collagenase. However, gamma-irradiated collagen did become more sensitive to hydrolysis by trypsin. The higher the irradiation doses used, the greater sensitivity to trypsin was observed. At 0.25 Mrads irradiation only a slight increase was found. No marked differences in amino acid composition were noted among the high dose irradiated, low dose irradiated and control amnion collagen.

  9. Effect of millimeter waves on cyclophosphamide induced suppression of the immune system.

    PubMed

    Logani, Mahendra K; Anga, Altaf; Szabo, Imre; Agelan, Alexis; Irizarry, Armando R; Ziskin, Marvin C

    2002-12-01

    The effect of millimeter electromagnetic waves (MWs) on cyclophosphamide (CPA) induced toxicity to leukocytes, bone marrow cells, and T-cell-mediated immunity was examined. For studying the effect of MWs on CPA induced leukopenia and myelosuppression, BALB/C mice were irradiated for 3 days, 30 min each day, prior to administration of CPA (200 mg/kg). MWs were produced with a Russian made YAV-1 generator. The device produced 42.2 +/- 0.2 GHz modulated wave radiation through a 10 mm x 20 mm rectangular output horn. The animals were irradiated on the nose area. Peak SAR and incident power density were measured as 622 +/- 100 W/kg and 31 +/- 5 mW/cm(2), respectively. For studying the effect of MWs on CPA induced suppression of T-cell mediated immunity, a delayed type hypersensitivity (DTH) assay in mouse skin was used. The DTH reaction in mouse skin was induced by topical application of dinitrochlorobenzene (DNCB) and quantified by measuring the increase in ear thickness and by histological examination. Treatment of animals with CPA significantly (P < 0.05) reduced leukocyte and bone marrow cell population, but MW irradiation did not show any significant protection from the immunosuppressive effects of CPA. Furthermore, MW irradiation did not protect the animals from CPA induced suppression of T-cell mediated immunity.

  10. Phytosanitary irradiation and fresh fruit quality: Cultivar and maturity effects

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Irradiation is an effective quarantine treatment for global trade of fresh produce. Variation in cultivars and maturity stages can impact the tolerance of fresh fruits to irradiation for the purposes of quarantine security. Tolerance thresholds for irradiated fruit are lacking for a large number of ...

  11. EFFECTS OF GAMMA IRRADIATION ON EPDM ELASTOMERS

    SciTech Connect

    Clark, E.

    2011-09-22

    Two formulations of EPDM elastomer, one substituting a UV stabilizer for the normal antioxidant in this polymer, and the other the normal formulation, were synthesized and samples of each were exposed to gamma irradiation in initially pure deuterium gas to compare their radiation stability. Stainless steel containers having rupture disks were designed for this task. After 130 MRad dose of cobalt-60 radiation in the SRNL Gamma Irradiation Facility, a significant amount of gas was created by radiolysis; however the composition indicated by mass spectroscopy indicated an unexpected increase in the total amount deuterium in both formulations. The irradiated samples retained their ductility in a bend test. No change of sample weight, dimensions, or density was observed. No change of the glass transition temperature as measured by dynamic mechanical analysis was observed, and most of the other dynamic mechanical properties remained unchanged. There appeared to be an increase in the storage modulus of the irradiated samples containing the UV stabilizer above the glass transition, which may indicate hardening of the material by radiation damage. Polymeric materials become damaged by exposure over time to ionizing radiation. Despite the limited lifetime, polymers have unique engineering material properties and polymers continue to be used in tritium handling systems. In tritium handling systems, polymers are employed mainly in joining applications such as valve sealing surfaces (eg. Stem tips, valve packing, and O-rings). Because of the continued need to employ polymers in tritium systems, over the past several years, programs at the Savannah River National Laboratory have been studying the effect of tritium on various polymers of interest. In these studies, samples of materials of interest to the SRS Tritium Facilities (ultra-high molecular weight polyethylene (UHMW-PE), polytetrafluoroethylene (PTFE, Teflon{reg_sign}), Vespel{reg_sign} polyimide, and the elastomer

  12. Suppression of pokeweed mitogen-stimulated immunoglobulin production in patients with rheumatoid arthritis after treatment with total lymphoid irradiation

    SciTech Connect

    Kotzin, B.L.; Strober, S.; Kansas, G.S.; Terrell, C.P.; Engleman, E.G.

    1984-02-01

    Patients with intractable rheumatoid arthritis (RA) were treated with total lymphoid irradiation (TLI, 200 rad). The authors previously reported long-lasting clinical improvement in this group associated with a persistent decrease in circulating Leu-3 (helper subset) T cells and marked impairment of in vitro lymphocyte function. In the present experiments, they studied the mechanisms underlying the decrease in pokeweed mitogen stimulated immunoglobulin (Ig) secretion observed after TLI. Peripheral blood mononuclear cells (PBL) from TLI-treated patients produced 10-fold less Ig (both IgM and IgG) in response to pokeweed mitogen than before radiotherapy. This decrease in Ig production was associated with the presence of suppressor cells in co-culture studies. By using responder cells obtained from normal individuals (allogeneic system), PBL from eight of 12 patients after TLI suppressed Ig synthesis by more than 50%. In contrast, PBL from the same patients before TLI failed to suppress Ig synthesis. PBL with suppressive activity contained suppressor T cells, and the latter cells bore the Leu-2 surface antigen. In 50% of the patients studied suppressor cells were also found in the non-T fraction and were adherent to plastic. Interestingly, the Leu-2/sup +/ cells from TLI-treated patients were no more potent on a cell per cell basis than purified Leu-2/sup +/ cells obtained before TLI. Additional experiments suggested that the suppression mediated by T cells after TLI is related to the increased ratio of Leu-2 to Leu-3 cells observed after radiotherapy.

  13. Biological effects of ultraviolet irradiation on bees

    SciTech Connect

    Es`kov, E.K.

    1995-09-01

    The influence of natural solar and artificial ultraviolet irradiation on developing bees was studied. Lethal exposures to irradiation at different stages of development were determined. The influence of irradiation on the variability of the morphometric features of bees was revealed. 5 refs., 1 fig.

  14. Post irradiation effects (PIE) in integrated circuits

    NASA Technical Reports Server (NTRS)

    Shaw, D. C.; Lowry, L.; Barnes, C.; Zakharia, M.; Agarwal, S.; Rax, B.

    1991-01-01

    Post-irradiation effects (PIE) ranging from normal recovery to catastrophic failure have been observed in integrated circuits during the PIE period. Data presented show failure due to rebound after a 10 krad(Si) dose. In particular, five device types are investigated with varying PIE response. Special attention has been given to the HI1-507A analog multiplexer because its PIE response is extreme. X-ray diffraction has been uniquely employed to measure physical stress in the HI1-507A metallization. An attempt has been made to show a relationship between stress relaxation and radiation effects. All data presented support the current MIL-STD Method 1019.4 but demonstrate the importance of performing PIE measurements, even when mission doses are as low as 10 krad(Si).

  15. Effect of low-level laser irradiating point on immunity

    NASA Astrophysics Data System (ADS)

    Cai, ChangSong; Qi, Qiong-fang; Xin, Jiang

    1993-03-01

    This paper reports that cellular immune function was observed when He-Ne laser was used to irradiate `zusanli' point in rats using various power, time, and periods. The indicator was a lymphocyte transformation test (LTT) by MTT colorimetric analysis. The best irradiating condition was determined, the effect and both virtues and defects of the laser were compared with those of electropuncture. The results show (1) LTT was enhanced in the group of laser irradiating point, but LTT was not enhanced in non-point (t' test, P < 0.01). (2) Lower power -- 2 mW or 5 mW of irradiating for 15 - 20 min, was better; 10 mW or 20 mW of irradiating for 10 - 15 min was suitable. Prolonged irradiating time did not enhance the immune function of the rats. On the contrary, immune function was inhibited. (3) A 7-day period of irradiating was best (once a day, 10 mW for 10 min). Enhanced LTT was not seen when irradiation days were added (SNK, P > 0.05). (4) Laser irradiation point and electropuncture were compared with vehicle control, LTT in the former two groups was enhanced significantly (ANOVA, P < 0.01), and laser irradiating point and electropuncture had the same effect (SNK, P > 0.05). The data suggest that laser irradiating point was able to enhance cell immunity and the enhancement of LTT had a point specific characteristic. The best condition of laser irradiating point was 2 mW for 15 - 20 min, and 10 mW or 20 mW for 10 - 15 min. The best period was 7-day irradiation. The results show laser irradiating the point may activate the main and collateral channels system, then modify the immune function of the body. Our observations provide experimental evidence for proper clinical application of laser irradiating points. The paper theoretically discusses and analyzes the experiment results in detail.

  16. A development and biological safety evaluation of novel PVC medical devices with surface structures modified by UV irradiation to suppress plasticizer migration.

    PubMed

    Haishima, Yuji; Isama, Kazuo; Hasegawa, Chie; Yuba, Toshiyasu; Matsuoka, Atsuko

    2013-09-01

    This study examines the chemical, physicochemical, and biological properties of PVC sheets treated with UV irradiation on their surfaces to suppress the elution of a plasticizer, di-(2-ethylhexyl) phthalate (DEHP), for developing novel polyvinyl chloride (PVC) medical devices. The PVC sheets irradiated under conditions 1 (52.5 μW/cm(2), 136 J/cm(2)) and 2 (0.45 mW/cm(2), 972 J/cm(2)) exhibited considerable toxicity in cytotoxicity tests and chromosome aberration tests due to the generation of DEHP oxidants, but no toxicity was detected in the PVC sheet irradiated under condition 3 (8.3 mW/cm(2), 134 J/cm(2)). The release of DEHP from the surface irradiated under condition 3 was significantly suppressed, and mono-(2-ethylhexyl) phthalate (MEHP) converted from a portion of DEHP could be easily removed from the surface by washing with methanol. The physicochemical properties of the surface regarding the suppression of DEHP elution remained stable through all sterilizations tested, but MEHP elution was partially recrudesced by the sterilizations except for gamma irradiation. These results indicated that UV irradiation using a strong UV-source over a short time (condition 3) followed by methanol washing and gamma sterilization may be useful for preparing novel PVC products that did not elute plasticizers and do not exhibit toxicity originating from UV irradiation.

  17. The irradiation effects on zirconium alloys

    NASA Astrophysics Data System (ADS)

    Negut, Gh.; Ancuta, M.; Radu, V.; Ionescu, S.; Stefan, V.; Uta, O.; Prisecaru, I.; Danila, N.

    2007-05-01

    Pressure tube samples were irradiated under helium atmosphere in the TRIGA Steady State Research and Material Test Reactor of the Romanian Institute for Nuclear Research (INR). These samples are made of the Zr-2.5%Nb alloy used as structural material for the CANDU Romanian power reactors. After irradiation, mechanical tests were performed in the Post Irradiation Examination Laboratory (PIEL) to study the influence of irradiation on zirconium alloys mechanical behaviour. The tensile test results were used for structural integrity assessment. Results of the tests are presented. The paper presents, also, pressure tube structural integrity assessment.

  18. Chronic Juvenile Delinquency and the "Suppression Effect": An Exploratory Study.

    ERIC Educational Resources Information Center

    Fraser, Mark; Norman, Michael

    1988-01-01

    Notes that fear of apprehension and punishment have been reported to suppress juvenile crime. Discusses suppression effect in regard to the correlates of chronic juvenile delinquency and exploratory evidence that youth who commit large volume of crime do not fear sanctions imposed by juvenile court any more than youth who commit only one offense…

  19. Effect of Electron Beam Irradiation on Tensile Strength of Polypropylene

    NASA Astrophysics Data System (ADS)

    Yamada, Hiroshi; Ikeda, Masayuki; Shimbo, Minoru; Miyano, Yasushi

    In this paper, the effects of the intensity of electron beam and the variation with time after irradiation of electron beam on the tensile strength of the polypropylene (PP), which is widely used as medicine containers, were investigated. PP with and without colorants were used first and samples irradiated under various intensity of EB. A tensile test on the irradiated samples with elapsed time after the irradiation of the electron beam was carried out. The effects of those factors on the tensile strength were discussed. The following results were obtained (1) The tensile strength of PP decreased due to the influence of the electron beam irradiation, however the rate of the decrease in strength was small compared with the original one. Furthermore, the rate of the decrease in strength was very small owing to the variation with time after the EB irradiation. (2) The tensile rupture strength of PP increased and the rupture strain owing to the influence of the electron beam irradiation compared with the original one. In addition, these rupture strength increased and the rupture strain decreased along with time after the irradiation of the electron beam. (3) The tensile rupture strain energy of PP decreased owing to the influence of the electron beam irradiation compared with the original one. In addition, the strain energy decreases with time after the irradiation of the electron beam. Moreover, the strength characteristics of PP with colorants received greater influence of electron beam compared with the one without colorants.

  20. Cost effective alternative to low irradiance measurements

    NASA Technical Reports Server (NTRS)

    Oleary, Scott T.

    1988-01-01

    Martin Marietta's Space Simulation Laboratory (SSL) has a Thermal Environment Simulator (TES) with 56 individually controlled heater zones. The TES has a temperature range of approximately minus 129 C to plus 149 C. Because of the ability of TES to provide complex irradiance distributions, it is necessary to be able to measure a wide range of irradiance levels. SSL currently uses ambient temperature controlled radiometers with the capacity to measure sink irradiance levels of approximately 42.6 mw/sq cm, sink temperature equals 21 C and up. These radiometers could not be used to accurately measure the lower irradiance levels of the TES. Therefore, it was necessary to obtain a radiometer or develop techniques which could be used to measure lower irradiance levels.

  1. Attenuating social affective learning effects with Memory Suppression manipulations.

    PubMed

    Molet, Mikael; Kosinski, Thierry; Craddock, Paul; Miguez, Gonzalo; Mash, Lisa E; Miller, Ralph R

    2016-02-01

    People can form opinions of other individuals based on information about their good or bad behavior. The present study investigated whether this affective learning might depend on memory links formed between initially neutral people and valenced information. First, participants viewed neutral faces paired with sentences describing prosocial or antisocial behaviors. Second, memory suppression manipulations with the potential to aid in the forgetting of valenced information were administered. Using the Think/No think paradigm, the effectiveness of four different suppression instructions was compared: Unguided Suppression, Guided Suppression, Distraction, and Thought Substitution. Overall, all the tasks appreciably reduced affective learning based on prosocial information, but only the Guided Suppression and Thought Substitution tasks reduced affective learning based on antisocial information. These results suggest that weakening the putative memory link between initially neutral people and valenced information can decrease the effect of learned associations on the evaluation of other people. We interpreted this as indicative that social affective learning may rely on declarative memories.

  2. Effect of gamma irradiation on Korean traditional multicolored paintwork

    NASA Astrophysics Data System (ADS)

    Yoon, Minchul; Kim, Dae-Woon; Choi, Jong-il; Chung, Yong-Jae; Kang, Dai-Ill; Hoon Kim, Gwang; Son, Kwang-Tae; Park, Hae-Jun; Lee, Ju-Woon

    2015-10-01

    Gamma irradiation can destroy fungi and insects involved in the bio-deterioration of organic cultural heritages. However, this irradiation procedure can alter optical and structural properties of historical pigments used in wooden cultural heritage paintings. The crystal structure and color centers of these paintings must be maintained after application of the irradiation procedure. In this study, we investigated the effects of gamma irradiation on Korean traditional multicolored paintwork (Dancheong) for the preservation of wooden cultural heritages. The main pigments in Korean traditional wooden cultural heritages, Sukganju (Hematite; Fe2O3), Jangdan (Minium; Pb3O4), Whangyun (Crocoite; PbCrO4), and Jidang (Rutile; TiO2), were irradiated by gamma radiation at doses of 1, 5, and 20 kGy. After irradiation, changes in Commision Internationale d'Eclairage (CIE) color values (L*, a*, b*) were measured using the color difference meter, and their structural changes were analyzed using X-ray diffraction (XRD) analysis. The slightly change in less than 1 dE* unit by gamma irradiation was observed, and structural changes in the Dancheong were stable after exposure to 20 kGy gamma irradiation. In addition, gamma irradiation could be applied to painted wooden cultural properties from the Korean Temple. Based on the color values, gamma irradiation of 20 kGy did not affect the Dancheong and stability was maintained for five months. In addition, the fungicidal and insecticidal effect by less than 5 kGy gamma irradiation was conformed. Therefore, the optical and structural properties of Dancheong were maintained after gamma irradiation, which suggested that gamma irradiation can be used for the preservation of wooden cultural heritages painted with Dancheong.

  3. Thermal effects in IR-laser-irradiated living cells

    NASA Astrophysics Data System (ADS)

    Meier, Thomas H.; Rueck, Angelika C.; Scalfi-Happ, Claudia; Hug, Hubert; Schneider, Marion E.

    2003-10-01

    Irradiation of cell-layers with focussed 2.8 μm ir-laser allows to control the cell temperature from room temperature up to 100°C. Temperatures were calculated for a cell culture model and verified experimentally by thermal mapping of the cell-surrounding medium by means of thermochromic liquid crystals (TLC). Irradiation power and time were varied and associated biological effects like necrosis and apoptosis were observed with respect to the irradiation dosis.

  4. Inhibiting the Aurora B Kinase Potently Suppresses Repopulation During Fractionated Irradiation of Human Lung Cancer Cell Lines

    SciTech Connect

    Sak, Ali; Stuschke, Martin; Groneberg, Michael; Kuebler, Dennis; Poettgen, Christoph; Eberhardt, Wilfried E.E.

    2012-10-01

    Purpose: The use of molecular-targeted agents during radiotherapy of non-small-cell lung cancer (NSCLC) is a promising strategy to inhibit repopulation, thereby improving therapeutic outcome. We assessed the combined effectiveness of inhibiting Aurora B kinase and irradiation on human NSCLC cell lines in vitro. Methods and Materials: NSCLC cell lines were exposed to concentrations of AZD1152-hydroxyquinazoline pyrazol anilide (AZD1152-HQPA) inhibiting colony formation by 50% (IC50{sub clone}) in combination with single dose irradiation or different fractionation schedules using multiple 2-Gy fractions per day up to total doses of 4-40 Gy. The total irradiation dose required to control growth of 50% of the plaque monolayers (TCD50) was determined. Apoptosis, G2/M progression, and polyploidization were also analyzed. Results: TCD50 values after single dose irradiation were similar for the H460 and H661 cell lines with 11.4 {+-} 0.2 Gy and 10.7 {+-} 0.3 Gy, respectively. Fractionated irradiation using 3 Multiplication-Sign 2 Gy/day, 2 Multiplication-Sign 2 Gy/day, and 1 Multiplication-Sign 2 Gy/day schedules significantly increased TCD50 values for both cell lines grown as plaque monolayers with increasing radiation treatment time. This could be explained by a repopulation effect per day that counteracts 75 {+-} 8% and 27 {+-} 6% of the effect of a 2-Gy fraction in H460 and H661 cells, respectively. AZD1152-HQPA treatment concomitant to radiotherapy significantly decreased the daily repopulation effect (H460: 28 {+-} 5%, H661: 10 {+-} 4% of a 2-Gy fraction per day). Treatment with IC50{sub clone} AZD1152-HPQA did not induce apoptosis, prolong radiation-induced G2 arrest, or delay cell cycle progression before the spindle check point. However, polyploidization was detected, especially in cell lines without functional p53. Conclusions: Inhibition of Aurora B kinase with low AZD1152-HQPA concentrations during irradiation of NSCLC cell lines affects repopulation during

  5. Gamma irradiation effects in W films

    SciTech Connect

    Claro, Luiz H.; Santos, Ingrid A.; Silva, Cassia F.

    2013-05-06

    Using the van Der Pauw methodology, the surface resistivity of irradiated tungsten films deposited on Silicon substrate was measured. The films were exposed to {gamma} radiation using a isotopic {sup 60}Co source in three irradiation stages attaining 40.35 kGy in total dose. The obtained results for superficial resistivity display a time annealing features and their values are proportional to the total dose.

  6. Effect of laser irradiation of donor blood on erythrocyte shape.

    PubMed

    Baibekov, I M; Ibragimov, A F; Baibekov, A I

    2012-04-01

    Changes in erythrocyte shape in donor blood during storage and after irradiation with He-Ne laser and infrared laser were studied by scanning electron microscopy, thick drop express-method, and morphometry. It was found that laser irradiation delayed the appearance of erythrocytes of pathological shapes (echinocytes, stomatocytes, etc.) in the blood; He-Ne laser produced a more pronounced effect.

  7. Effect of. gamma. -ray irradiation on alcohol production from corn

    SciTech Connect

    Han, Y.W.; Cho, Y.K.; Ciegler, A.

    1983-11-01

    Cracked corn was irradiated with ..gamma.. rays at 0-100 Mrad and the effects of the irradiation on sugar yield, susceptibility to enzymatic hydrolysis of starch, yeast growth, and alcohol production were studied. Gamma irradiation at 50 Mrad or greater produced a considerable amount of reducing sugar but little glucose. At lower dosages, ..gamma.. irradiation significantly increased the susceptibility of corn starch to enzymatic hydrolysis, but dosages of 50 Mrad or greater decomposed the starch molecules as indicated by the reduction in iodine uptake. About 12.5% reducing sugar was produced by amylase treatment of uncooked, irradiated corn. This amount exceeded the level of sugar produced from cooked (gelatinized) corn by the same enzyme treatment. The yeast numbers in submerged cultivation were lower on a corn substrate that was irradiated at 50 Mrad or greater compared to that on an unirradiated control. About the same level of alcohol was produced on uncooked, irradiated (10/sup 5/ - 10/sup 6/ rad) corn as from cooked (121 degrees C for 30 min) corn. Therefore, the conventional cooking process for gelatinization of starch prior to its saccharification can be eliminated by irradiation. Irradiation also eliminated the necessity of sterilization of the medium and reduced the viscosity of high levels of substrate in the fermentation broth. (Refs. 10).

  8. Effect of sheath gas in atmospheric-pressure plasma jet for potato sprouting suppression

    NASA Astrophysics Data System (ADS)

    Nishiyama, S.; Monma, M.; Sasaki, K.

    2016-09-01

    Recently, low-temperature atmospheric-pressure plasma jets (APPJs) attract much interest for medical and agricultural applications. We try to apply APPJs for the suppression of potato sprouting in the long-term storage. In this study, we investigated the effect of sheath gas in APPJ on the suppression efficiency of the potato sprouting. Our APPJ was composed of an insulated thin wire electrode, a glass tube, a grounded electrode which was wound on the glass tube, and a sheath gas nozzle which was attached at the end of the glass tube. The wire electrode was connected to a rectangular-waveform power supply at a frequency of 3 kHz and a voltage of +/- 7 kV. Helium was fed through the glass tube, while we tested dry nitrogen, humid nitrogen, and oxygen as the sheath gas. Eyes of potatoes were irradiated by APPJ for 60 seconds. The sprouting probability was evaluated at two weeks after the plasma irradiation. The sprouting probability was 28% when we employed no sheath gases, whereas an improved probability of 10% was obtained when we applied dry nitrogen as the sheath gas. Optical emission spectroscopy was carried out to diagnose the plasma jet. It was suggested that reactive species originated from nitrogen worked for the efficient suppression of the potato sprouting.

  9. Critical suppression of spin Seebeck effect by magnetic fields

    NASA Astrophysics Data System (ADS)

    Kikkawa, Takashi; Uchida, Ken-ichi; Daimon, Shunsuke; Qiu, Zhiyong; Shiomi, Yuki; Saitoh, Eiji

    2015-08-01

    The longitudinal spin Seebeck effect (LSSE) in Pt /Y3Fe5O12(YIG ) junction systems has been investigated at various magnetic fields and temperatures. We found that the LSSE voltage in a Pt/YIG-slab system is suppressed by applying high magnetic fields and this suppression is critically enhanced at low temperatures. The field-induced suppression of the LSSE in the Pt/YIG-slab system is too large at around room temperature to be explained simply by considering the effect of the Zeeman gap in magnon excitation. This result requires us to introduce a magnon-frequency-dependent mechanism into the scenario of LSSE; low-frequency magnons dominantly contribute to the LSSE. The magnetic field dependence of the LSSE voltage was observed to change by changing the thickness of YIG, suggesting that the thermospin conversion by the low-frequency magnons is suppressed in thin YIG films due to the long characteristic lengths of such magnons.

  10. The effects of sunspots on solar irradiance

    NASA Technical Reports Server (NTRS)

    Hudson, H. S.; Silva, S.; Woodard, M.; Willson, R. C.

    1982-01-01

    It is pointed out that the darkness of a sunspot on the visible hemisphere of the sun will reduce the solar irradiance on the earth. Approaches are discussed for obtaining a crude estimate of the irradiance deficit produced by sunspots and of the total luminosity reduction for the whole global population of sunspots. Attention is given to a photometric sunspot index, a global measure of spot flux deficit, and models for the compensating flux excess. A model is shown for extrapolating visible-hemisphere spot areas to the invisible hemisphere. As an illustration, this extrapolation is used to calculate a very simple model for the reradiation necessary to balance the flux deficit.

  11. Protective effects of polyvinylpyrrolidone-wrapped fullerene against intermittent ultraviolet-A irradiation-induced cell injury in HaCaT cells.

    PubMed

    Saitoh, Yasukazu; Ohta, Hiroaki; Hyodo, Sayuri

    2016-10-01

    To identify compounds that suppress UV irradiation-induced oxidative stress in the skin, various types of antioxidants have been studied. Polyvinylpyrrolidone-entrapped fullerene (C60/PVP) is known as a powerful antioxidant that exerts a cytoprotective effect against UV irradiation-induced cell injury in human skin cells and skin models. However, the effects of the alternate attractive C60/PVP feature, persistent antioxidant ability, on cytoprotection have rarely been ascertained. In this study we therefore investigated the efficacies of C60/PVP using an intermittently repeated UVA irradiation model wherein human keratinocytes were repeatedly exposed to UVA five times every 1h and compared the cytoprotective effects with those provided by ascorbic acid-2-O-phosphate-disodium salt (APS) and α-tocopherol (α-Toc). Our results demonstrated that C60/PVP yielded prominent cytoprotective effects against intermittently repeated UVA irradiation-induced injuries in a dose-dependent manner and suppressed intracellular superoxide anion radical (O2(-)) generation both during and after the repeated UVA irradiation. Additionally, C60/PVP also repressed the intermittent UVA irradiation-induced apoptosis via suppression of chromatin condensation and caspase-3/7 activation. Furthermore, the observed cytoprotective effects were superior to the effects of the typical antioxidants APS and α-Toc. These data suggest that C60/PVP might function as a potent cosmetic antioxidant against the effects of repeated and prolonged UVA irradiation through its persistent antioxidative property.

  12. Effects of irradiation on Planococcus minor (Hemiptera: Pseudococcidae).

    PubMed

    Ravuiwasa, Kaliova Tavou; Lu, Kuang-Hui; Shen, Tse-Chi; Hwang, Shaw-Yhi

    2009-10-01

    Irradiation has been recognized and endorsed as a potential phytosanitary measure that could be an alternative to current quarantine treatments. Dosages of 50, 100, 150, 200, and 250 Gy were used to irradiate three different life stages (eggs, immatures, and adults) of Planococcus minor (Maskell) (Hemiptera: Pseudococcidae), focusing on females due to its parthenogenesis ability, with an aim to find the most tolerant stage and the most optimal dose to control P. minor. Cobalt 60 was the source of irradiation used. Irradiation of 150-250 Gy has a significant effect on all life stages of P. minor, decreasing its survival rate, percentage of adult reproduction, oviposition, and fertility rate. The adult was the most tolerant life stage in both mortality and fertility rate. All the different irradiated target life stage groups oviposited eggs, but none of the F2 eggs hatched at the most optimal dosage of 150-250 Gy.

  13. Inhibition of Autophagy Enhances Curcumin United light irradiation-induced Oxidative Stress and Tumor Growth Suppression in Human Melanoma Cells

    PubMed Central

    Niu, Tianhui; Tian, Yan; Mei, Zhusong; Guo, Guangjin

    2016-01-01

    Malignant melanoma is the most aggressive form of skin carcinoma, which possesses fast propagating and highly invasive characteristics. Curcumin is a natural phenol compound that has various biological activities, such as anti-proliferative and apoptosis-accelerating impacts on tumor cells. Unfortunately, the therapeutical activities of Cur are severely hindered due to its extremely low bioavailability. In this study, a cooperative therapy of low concentration Cur combined with red united blue light irradiation was performed to inspect the synergistic effects on the apoptosis, proliferation and autophagy in human melanoma A375 cell. The results showed that red united blue light irradiation efficaciously synergized with Cur to trigger oxidative stress-mediated cell death, induce apoptosis and inhibit cell proliferation. Meanwhile, Western blotting revealed that combined disposure induced the formation of autophagosomes. Conversely, inhibition of the autophagy enhanced apoptosis, obstructed cell cycle arrest and induced reversible proliferation arrest to senescence. These findings suggest that Cur combined with red united blue light irradiation could generate photochemo-preventive effects via enhancing apoptosis and triggering autophagy, and pharmacological inhibition of autophagy convert reversible arrested cells to senescence, therefore reducing the possibility that damaged cells might escape programmed death. PMID:27502897

  14. Effects of Ultrasonic Irradiation on Phenolic Compounds in Wine

    NASA Astrophysics Data System (ADS)

    Masuzawa, Nobuyoshi; Ohdaira, Etsuzo; Ide, Masao

    2000-05-01

    Red wine has been of interest recently because many poly-phenols, that are considered to be good for health, are contained therein. Since ultrasonic irradiation accelerates maturation, its effects on phenolic compounds in wine were investigated in this study. Effects were evaluated using the indices developed by Glories. It was found that weak ultrasonic irradiation promotes an increase in the amount of phenolic compounds in red wine.

  15. Diffraction effects on broadband radiation: formulation for computing total irradiance.

    PubMed

    Shirley, Eric L

    2004-05-01

    I present a formulation for treating diffraction effects on total irradiance in the case of a Planck source; earlier work generally depended on calculating diffraction effects on spectral irradiance followed by summation over spectral components. The formulation is derived and demonstrated for Fraunhofer diffraction by circular apertures, rectangular apertures and slits, and Fresnel diffraction by circular apertures. The prospects for treating other sources and optical systems are also discussed.

  16. Preliminary analysis of irradiation effects on CLAM after low dose neutron irradiation

    NASA Astrophysics Data System (ADS)

    Peng, Lei; Huang, Qunying; Li, Chunjing; Liu, Shaojun

    2009-04-01

    To investigate the irradiation effects on a new version of reduced activation ferritic/martensitic steels (RAFMs) i.e. China Low Activation Martensitic steel (CLAM), neutron irradiation experiments has been being carried out under wide collaboration in China and overseas. In this paper, the mechanical properties of CLAM heats 0603A, 0408B, and 0408D were investigated before and after neutron irradiation to ˜0.02 dpa at 250 °C. The test results showed that ultimate strength and yield stress of CLAM HEAT 0603A increased about 10-30 MPa and ductile to brittle transition temperature (DBTT) shift was about 5 °C. For CLAM heats 0408B and 0408D, ultimate strength and yield stress increased about 80-150 MPa.

  17. Proton irradiation effects on beryllium – A macroscopic assessment

    SciTech Connect

    Simos, Nikolaos; Elbakhshwan, Mohamed; Zhong, Zhong; Camino, Fernando

    2016-07-01

    Beryllium, due to its excellent neutron multiplication and moderation properties, in conjunction with its good thermal properties, is under consideration for use as plasma facing material in fusion reactors and as a very effective neutron reflector in fission reactors. While it is characterized by unique combination of structural, chemical, atomic number, and neutron absorption cross section it suffers, however, from irradiation generated transmutation gases such as helium and tritium which exhibit low solubility leading to supersaturation of the Be matrix and tend to precipitate into bubbles that coalesce and induce swelling and embrittlement thus degrading the metal and limiting its lifetime. Utilization of beryllium as a pion production low-Z target in high power proton accelerators has been sought both for its low Z and good thermal properties in an effort to mitigate thermos-mechanical shock that is expected to be induced under the multi-MW power demand. To assess irradiation-induced changes in the thermal and mechanical properties of Beryllium, a study focusing on proton irradiation damage effects has been undertaken using 200 MeV protons from the Brookhaven National Laboratory Linac and followed by a multi-faceted post-irradiation analysis that included the thermal and volumetric stability of irradiated beryllium, the stress-strain behavior and its ductility loss as a function of proton fluence and the effects of proton irradiation on the microstructure using synchrotron X-ray diffraction. The mimicking of high temperature irradiation of Beryllium via high temperature annealing schemes has been conducted as part of the post-irradiation study. This study focuses on the thermal stability and mechanical property changes of the proton irradiated beryllium and presents results of the macroscopic property changes of Beryllium deduced from thermal and mechanical tests.

  18. Proton irradiation effects on beryllium - A macroscopic assessment

    NASA Astrophysics Data System (ADS)

    Simos, Nikolaos; Elbakhshwan, Mohamed; Zhong, Zhong; Camino, Fernando

    2016-10-01

    Beryllium, due to its excellent neutron multiplication and moderation properties, in conjunction with its good thermal properties, is under consideration for use as plasma facing material in fusion reactors and as a very effective neutron reflector in fission reactors. While it is characterized by unique combination of structural, chemical, atomic number, and neutron absorption cross section it suffers, however, from irradiation generated transmutation gases such as helium and tritium which exhibit low solubility leading to supersaturation of the Be matrix and tend to precipitate into bubbles that coalesce and induce swelling and embrittlement thus degrading the metal and limiting its lifetime. Utilization of beryllium as a pion production low-Z target in high power proton accelerators has been sought both for its low Z and good thermal properties in an effort to mitigate thermos-mechanical shock that is expected to be induced under the multi-MW power demand. To assess irradiation-induced changes in the thermal and mechanical properties of Beryllium, a study focusing on proton irradiation damage effects has been undertaken using 200 MeV protons from the Brookhaven National Laboratory Linac and followed by a multi-faceted post-irradiation analysis that included the thermal and volumetric stability of irradiated beryllium, the stress-strain behavior and its ductility loss as a function of proton fluence and the effects of proton irradiation on the microstructure using synchrotron X-ray diffraction. The mimicking of high temperature irradiation of Beryllium via high temperature annealing schemes has been conducted as part of the post-irradiation study. This paper focuses on the thermal stability and mechanical property changes of the proton irradiated beryllium and presents results of the macroscopic property changes of Beryllium deduced from thermal and mechanical tests.

  19. Proton irradiation effects on beryllium – A macroscopic assessment

    DOE PAGES

    Simos, Nikolaos; Elbakhshwan, Mohamed; Zhong, Zhong; ...

    2016-07-01

    Beryllium, due to its excellent neutron multiplication and moderation properties, in conjunction with its good thermal properties, is under consideration for use as plasma facing material in fusion reactors and as a very effective neutron reflector in fission reactors. While it is characterized by unique combination of structural, chemical, atomic number, and neutron absorption cross section it suffers, however, from irradiation generated transmutation gases such as helium and tritium which exhibit low solubility leading to supersaturation of the Be matrix and tend to precipitate into bubbles that coalesce and induce swelling and embrittlement thus degrading the metal and limiting itsmore » lifetime. Utilization of beryllium as a pion production low-Z target in high power proton accelerators has been sought both for its low Z and good thermal properties in an effort to mitigate thermos-mechanical shock that is expected to be induced under the multi-MW power demand. To assess irradiation-induced changes in the thermal and mechanical properties of Beryllium, a study focusing on proton irradiation damage effects has been undertaken using 200 MeV protons from the Brookhaven National Laboratory Linac and followed by a multi-faceted post-irradiation analysis that included the thermal and volumetric stability of irradiated beryllium, the stress-strain behavior and its ductility loss as a function of proton fluence and the effects of proton irradiation on the microstructure using synchrotron X-ray diffraction. The mimicking of high temperature irradiation of Beryllium via high temperature annealing schemes has been conducted as part of the post-irradiation study. This study focuses on the thermal stability and mechanical property changes of the proton irradiated beryllium and presents results of the macroscopic property changes of Beryllium deduced from thermal and mechanical tests.« less

  20. Pilot-Scale Pulsed UV Light Irradiation of Experimentally Infected Raspberries Suppresses Cryptosporidium parvum Infectivity in Immunocompetent Suckling Mice.

    PubMed

    Le Goff, L; Hubert, B; Favennec, L; Villena, I; Ballet, J J; Agoulon, A; Orange, N; Gargala, G

    2015-12-01

    Cryptosporidium spp., a significant cause of foodborne infection, have been shown to be resistant to most chemical food disinfectant agents and infective for weeks in irrigation waters and stored fresh vegetal produce. Pulsed UV light (PL) has the potential to inactivate Cryptosporidium spp. on surfaces of raw or minimally processed foods or both. The present study aimed to evaluate the efficacy of PL on viability and in vivo infectivity of Cryptosporidium parvum oocysts present on raspberries, a known source of transmission to humans of oocyst-forming apicomplexan pathogens. The skin of each of 20 raspberries was experimentally inoculated with five 10-μl spots of an oocyst suspension containing 6 × 10(7) oocysts per ml (Nouzilly isolate). Raspberries were irradiated by PL flashes (4 J/cm(2) of total fluence). This dose did not affect colorimetric or organoleptic characteristics of fruits. After immunomagnetic separation from raspberries, oocysts were bleached and administered orally to neonatal suckling mice. Seven days after infection, mice were euthanized, and the number of oocysts in the entire small intestine was individually assessed by immunofluorescence flow cytometry. Three of 12 and 12 of 12 inoculated mice that received 10 and 100 oocysts isolated from nonirradiated raspberries, respectively, were found infected. Four of 12 and 2 of 12 inoculated mice that received 10(3) and 10(4) oocysts from irradiated raspberries, respectively, were found infected. Oocyst counts were lower in animals inoculated with 10(3) and 10(4) oocysts from irradiated raspberries (92 ± 144 and 38 ± 82, respectively) than in animals infected with 100 oocysts from nonirradiated raspberries (35,785 ± 66,221, P = 0.008). PL irradiation achieved oocyst reductions of 2 and 3 log for an inoculum of 10(3) and 10(4) oocysts, respectively. The present pilot-scale evaluation suggests that PL is an effective mode of decontamination for raspberries and prompts further applicability

  1. Suppressing CMB low multipoles with ISW effect

    SciTech Connect

    Das, Santanu; Souradeep, Tarun E-mail: tarun@iucaa.ernet.in

    2014-02-01

    Recent results of Planck data reveal that the power [1,2] in the low multipoles of the CMB angular power spectrum, approximately up to l = 30, is significantly lower than the theoretically predicted in the best fit ΛCDM model. There are different known physical effects that can affect the power at low multipoles, such as features in the primordial power spectrum (PPS) in some models of inflation and ISW effect. In this paper we investigate the possibility of invoking the Integrated Sachs-Wolfe (ISW) effect to explain the power deficit at low multipoles. The ISW effect that originates from the late time expansion history of the universe is rich in possibilities given the limited understanding of the origin of dark energy (DE). It is a common understanding that the ISW effect adds to the power at the low multipoles of the CMB angular power spectrum. In this paper we carry out an analytic study to show that there are some expansion histories in which the ISW effect, instead of adding power, provides negative contribution to the power at low multipoles. Guided by the analytic study, we present examples of the features required in the late time expansion history of the universe that could explain the power deficiency through the ISW effect. We also show that an ISW origin of power deficiency is consistent, at present, with other cosmological observations that probe the expansion history such as distance modulus, matter power spectrum and the evolution of cluster number count. We also show that the ISW effect may be distinguished from power deficit originating from features in the PPS using the measurements of the CMB polarization spectrum at low multipoles expected from Planck. We conclude that the power at low multipoles of the CMB anisotropy could well be closely linked to Dark Energy puzzle in cosmology and this observation could be actually pointing to richer phenomenology of DE beyond the cosmological constant Λ.

  2. Effect of burst parameters on automotive brake squeal suppression

    NASA Astrophysics Data System (ADS)

    Badertscher, Jeff; Cunefare, Kenneth A.

    2003-04-01

    Implementing a dither control signal with a 100% duty cycle is an effective means of suppressing automotive brake squeal. Dither control is a method by which high-frequency control efforts are introduced into a system to suppress a lower frequency disturbance. Dither is introduced to a brake by placing a piezoelectric stack actuator in the piston of a floating caliper brake. Burst mode dither control is characterized by duty cycles of less than 100%. A burst control signal of a specific duty cycle is also specified by the burst count and burst rate. Burst mode signals are shown to suppress brake squeal. This paper examines the nature of suppression and the effectiveness of burst mode dither control signals with varied burst parameters. An examination of the squeal response and dither control signal is used to examine the nature of suppression during bursting and dwell time. The amplitude of the control signal that is necessary to obtain full control of the system is used to assess control signal effectiveness.

  3. The study of gamma irradiation effects on poly (glycolic acid)

    NASA Astrophysics Data System (ADS)

    Rao Nakka, Rajeswara; Rao Thumu, Venkatappa; Reddy SVS, Ramana; Rao Buddhiraju, Sanjeeva

    2015-05-01

    We have investigated the effects of gamma irradiation on chemical structure, thermal and morphological properties of biodegradable semi-crystalline poly (glycolic acid) (PGA). PGA samples were subjected to irradiation treatment using a 60Co gamma source with a delivered dose of 30, 60 and 90 kGy, respectively. Gamma irradiation induces cleavage of PGA main chains forming ∼OĊH2 and ĊH2COO∼ radicals in both amorphous and crystalline regions. The free radicals formed in the amorphous region abstract atmospheric oxygen and convert them to peroxy radicals. The peroxy radical causes chain scission at the crystal interface through hydrogen abstraction from methylene groups forming the ∼ĊHCOO∼ (I) radical. Consequently, the observed electron spin resonance (ESR) doublet of irradiated PGA is assigned to (I). The disappearance of the ESR signal above 190°C indicates that free radicals are formed in the amorphous region and decay below the melting temperature of PGA. Fourier transform infrared and optical absorption studies confirm that the ? groups are not influenced by gamma irradiation. Differential scanning calorimetry (DSC) studies showed that the melting temperature of PGA decreased from 212°C to 202°C upon irradiation. Degree of crystallinity increased initially and then decreased with an increase in radiation as per DSC and X-ray diffraction studies. Irradiation produced changes in the physical properties of PGA as well as affecting the morphology of the material.

  4. Two phenotypically distinct T cells are involved in ultraviolet-irradiated urocanic acid-induced suppression of the efferent delayed-type hypersensitivity response to herpes simplex virus, type 1 in vivo

    SciTech Connect

    Ross, J.A.; Howie, S.E.; Norval, M.; Maingay, J.

    1987-09-01

    When UVB-irradiated urocanic acid, the putative photoreceptor/mediator for UVB suppression, is administered to mice it induces a dose-dependent suppression of the delayed-type hypersensitivity response to herpes simplex virus, type 1 (HSV-1), of similar magnitude to that induced by UV irradiation of mice. In this study, the efferent suppression of delayed-type hypersensitivity by UV-irradiated urocanic acid is demonstrated to be due to 2 phenotypically distinct T cells, (Thy1+, L3T4-, Ly2+) and (Thy1+, L3T4+, Ly2-). The suppression is specific for HSV-1. This situation parallels the generation of 2 distinct T-suppressor cells for HSV-1 by UV irradiation of mice and provides further evidence for the involvement of urocanic acid in the generation of UVB suppression.

  5. Discrete Element Model for Suppression of Coffee-Ring Effect

    NASA Astrophysics Data System (ADS)

    Xu, Ting; Lam, Miu Ling; Chen, Ting-Hsuan

    2017-02-01

    When a sessile droplet evaporates, coffee-ring effect drives the suspended particulate matters to the droplet edge, eventually forming a ring-shaped deposition. Because it causes a non-uniform distribution of solid contents, which is undesired in many applications, attempts have been made to eliminate the coffee-ring effect. Recent reports indicated that the coffee-ring effect can be suppressed by a mixture of spherical and non-spherical particles with enhanced particle-particle interaction at air-water interface. However, a model to comprehend the inter-particulate activities has been lacking. Here, we report a discrete element model (particle system) to investigate the phenomenon. The modeled dynamics included particle traveling following the capillary flow with Brownian motion, and its resultant 3D hexagonal close packing of particles along the contact line. For particles being adsorbed by air-water interface, we modeled cluster growth, cluster deformation, and cluster combination. We found that the suppression of coffee-ring effect does not require a circulatory flow driven by an inward Marangoni flow at air-water interface. Instead, the number of new cluster formation, which can be enhanced by increasing the ratio of non-spherical particles and the overall number of microspheres, is more dominant in the suppression process. Together, this model provides a useful platform elucidating insights for suppressing coffee-ring effect for practical applications in the future.

  6. Discrete Element Model for Suppression of Coffee-Ring Effect

    PubMed Central

    Xu, Ting; Lam, Miu Ling; Chen, Ting-Hsuan

    2017-01-01

    When a sessile droplet evaporates, coffee-ring effect drives the suspended particulate matters to the droplet edge, eventually forming a ring-shaped deposition. Because it causes a non-uniform distribution of solid contents, which is undesired in many applications, attempts have been made to eliminate the coffee-ring effect. Recent reports indicated that the coffee-ring effect can be suppressed by a mixture of spherical and non-spherical particles with enhanced particle-particle interaction at air-water interface. However, a model to comprehend the inter-particulate activities has been lacking. Here, we report a discrete element model (particle system) to investigate the phenomenon. The modeled dynamics included particle traveling following the capillary flow with Brownian motion, and its resultant 3D hexagonal close packing of particles along the contact line. For particles being adsorbed by air-water interface, we modeled cluster growth, cluster deformation, and cluster combination. We found that the suppression of coffee-ring effect does not require a circulatory flow driven by an inward Marangoni flow at air-water interface. Instead, the number of new cluster formation, which can be enhanced by increasing the ratio of non-spherical particles and the overall number of microspheres, is more dominant in the suppression process. Together, this model provides a useful platform elucidating insights for suppressing coffee-ring effect for practical applications in the future. PMID:28216639

  7. Dependence of Ion Energy on PTFE Surface Modification Effect by Nitrogen Ion Irradiation

    NASA Astrophysics Data System (ADS)

    Nakayama, Akihiko; Iwao, Toru; Yumoto, Motoshige

    PTFE (Poly-tetra-fluoro-ethylene) has superior characteristic. But, it has low adhesion force. In order to improve adhesion force, we have studied on surface modification of PTFE by using discharge under high E/n (E:electric field, n:particle density) condition in nitrogen. From the results, it was deduced that ion energy around 40 eV is effective for polar groups introduction. In addition, treated surface unevenness did not increase compared with the untreated one. Then, we performed nitrogen ion irradiation by changing ion energy. From the results, it is shown that low ion energy is effective for polar groups introduction. It is also shown that high energy ion suppresses surface roughness. Thus, we measured surface energy and composition of samples irradiated by high and low energy ions. When ion with 30 eV was irradiated for 5 minute and following it ion with 1060 eV was irradiated for 10 second, many polar groups were introduced and surface unevenness was kept at the untreatment level. From the results by XPS (X-ray Photoelectron Spectroscopy) analysis and FT-IR (Fourier transform Infrared Spectroscopy) analysis by using the ATR (Attenuated Total Reflection) method, it was confirmed that polar groups of oxygen component and cross-linked structure via nitrogen or carbon was introduced at the surface.

  8. Subtask 12F1: Effect of neutron irradiation on swelling of vanadium-base alloys

    SciTech Connect

    Chung, H.M.; Loomis, B.A.; Smith, D.L.

    1995-03-01

    The objective of this work is to determine the effects of neutron irradiation on the density change, void distribution, and microstructural evolution of vanadium-base alloys. Swelling behavior and microstructural evolution of V-Ti, V-Cr-Ti, and V-Ti-Si alloys were investigated after irradiation at 420-600{degrees}C up to 114 dpa. The alloys exhibited swelling maxima between 30 and 80 dpa and swelling decreased on irradiation to higher dpa. This is in contrast to the monotonically increasing swelling of binary alloys that contain Fe, Ni, Cr, Mo, W, and Si. Precipitation of dense Ti{sub 5}Si{sub 3} promotes good resistance to swelling of the Ti-containing alloys, and it was concluded that Ti of >3 wt.% and 400-1000 wppm Si are necessary to effectively suppress swelling. Swelling was minimal in V-4Cr-4Ti, identified as the most promising alloy based on good mechanical properties and superior resistance to irradiation embrittlement. 18 refs., 6 figs., 1 tab.

  9. Proton and neutron irradiation effect of Ti: Sapphires

    SciTech Connect

    Wang, G.; Zhang, J.; Yang, J.

    1999-07-01

    Various effects of proton and neutron irradiated Ti: sapphires were studied. Proton irradiation induced F, F{sup +} and V center in Ti: sapphires and 3310 cm{sup -1} infrared absorption, and made ultraviolet absorption edge shift to short wave. Neutron irradiation produced a number of F, F{sup +} and F{sub 2} centers and larger defects in Ti: sapphires, and changed Ti{sup 4+}into Ti{sup 3+} ions. Such valence state variation enhanced characteristic luminescence of Ti: sapphires, and no singular variances of intrinsic fluorescence spectra of Ti: sapphires took place with neutron flux of 1 x 10{sup 17}n/cm{sup 2}, but the fluorescence vanished with neutron flux of 1 x 10{sup 18}n/cm{sup 2} which means the threshold for the concentration of improving Ti{sup 3+} ions by neutron irradiation.

  10. Enhance-Synergism and Suppression Effects in Multiple Regression

    ERIC Educational Resources Information Center

    Lipovetsky, Stan; Conklin, W. Michael

    2004-01-01

    Relations between pairwise correlations and the coefficient of multiple determination in regression analysis are considered. The conditions for the occurrence of enhance-synergism and suppression effects when multiple determination becomes bigger than the total of squared correlations of the dependent variable with the regressors are discussed. It…

  11. Effect of irradiation on Brazilian honeys' consistency and their acceptability

    NASA Astrophysics Data System (ADS)

    Matsuda, A. H.; Sabato, S. F.

    2004-09-01

    Contamination of bee products may occur during packing or even during the process of collection. Gamma irradiation was found to decrease the number of bacteria and fungi. However, little information is available on the effects of gamma irradiation on viscosity which is an important property of honey. In this work the viscosity of two varieties of Brazilian honey was measured when they were irradiated at 5 and 10 kGy. The viscosity was measured at four temperatures (25°C, 30°C, 35°C and 40°C) for both samples and compared with control and within the doses. The sensory evaluation was carried on for the parameters color, odor, taste and consistency, using a 9-point hedonic scale. All the data were treated with a statistical tool (Statistica 5.1, StatSoft, 1998). The viscosity was not impaired significantly by gamma irradiation in doses 5 and 10 kGy ( p<0.05). The effect of gamma irradiation on sensorial characteristics (odor, color, taste and consistency) is presented. The taste for Parana type indicated a significant difference among irradiation doses ( p<0.05) but the higher value was for 5 kGy dose, demonstrating the acceptability for this case. The Organic honey presented the taste parameter for 10 kGy, significantly lower than the control mean but it did not differ significantly from the 5 kGy value.

  12. Irradiation-induced effects of proton irradiation on zirconium carbides with different stoichiometries

    SciTech Connect

    Y. Huang; B.R. Maier; T.R. Allen

    2014-10-01

    Zirconium carbide (ZrC) is being considered for utilization in deep burn TRISO fuel particles for hightemperature, gas-cooled reactors. Zirconium carbide has a cubic B1 type crystal structure along with a very high melting point (3420 ?C), exceptional hardness and good thermal and electrical conductivities. Understanding the ZrC irradiation response is crucial for establishing ZrC as an alternative component in TRISO fuel. Until now, very few studies on irradiation effects on ZrC have been released and fundamental aspects of defect evolution and kinetics are not well understood although some atomistic simulations and phenomenological studies have been performed. This work was carried out to understand the damage evolution in float-zone refined ZrC with different stoichiometries. Proton irradiations at 800 ?C up to doses of 3 dpa were performed on ZrCx (where x ranges from 0.9 to 1.2) to investigate the damage evolution. The irradiation-induced defects, such as density of dislocation loops, at different stoichiometries and doses which were characterized by transmission electron microscopy (TEM) is presented and discussed.

  13. Survival after total body irradiation: Effects of irradiation of exteriorized small intestine. (Reannouncement with new availability information)

    SciTech Connect

    Vriesendorp, H.M.; Vigneulle, R.M.; Kitto, G.; Pelky, T.; Taylor, P.

    1993-12-31

    Rats receiving lethal irradiation to their exteriorized small intestine with pulsed 18 MVp bremsstrahlung radiation live about 4 days longer than rats receiving a dose of total-body irradiation (TBI) causing intestinal death. The LD50 for intestinal irradiation is approximately 6 Gy higher than the LD50 for intestinal death after TBI. Survival time after exteriorized intestinal irradiation can be decreased, by adding abdominal irradiation. Adding thoracic or pelvic irradiation does not alter survival time. Shielding of large intestine improves survival after irradiation of the rest of the abdomen while the small intestine is also shielded. The kinetics of histological changes in small intestinal tissues implicate the release of humoral factors after irradiation of the abdomen. Radiation injury develops faster in the first (proximal) 40 cm of the small intestine and is expressed predominantly as shortening in villus height. In the last (distal) 40 cm of the small intestine, the most pronounced radiation effect is a decrease in the number of crypts per millimeter. Irradiation (20 Gy) of the proximal small intestine causes 92 % mortality (median survival 10 days). Irradiation (20 Gy) of the distal small intestine causes 27% mortality (median survival > 30 days). In addition to depletion of crypt stem cells in the small intestine, other issues (humoral factors, irradiated subsection of the small intestine and shielding of the large intestine) appear to influence radiation-induced intestinal mortality.

  14. Fetal pancreas transplantation in miniature swine. IV. Suppression of DTH and MLR responses by treatment with ultraviolet light-irradiated peripheral blood lymphocytes

    SciTech Connect

    Taura, Y.; Stein, E.; Miyazawa, K.; Mullen, Y. )

    1990-07-01

    Irradiation of peripheral blood lymphocytes of miniature swine with ultraviolet light prevented them from initiating proliferative responses in allogeneic mixed lymphocyte reactions and also reduced IL-2 production in these MLRs. When pigs were injected in a series of 4-5 weekly transfusions with UV-irradiated allogeneic PBL differing at the MHC, PBL of recipient pigs progressively responded less strongly to donor PBL in MLRs over the treatment period. These pigs also gave negligible delayed-type hypersensitivity responses to donor PBL at the end of the treatment period. Of the seven UV-irradiated PBL-treated pigs, four produced no antidonor PBL antibody and three produced antibody. Serum from the three antibody-producing pigs also suppressed MLRs of unrelated PBL. By contrast, pigs that received a series of injections of untreated allogeneic PBL gave strong DTH responses to donor PBL and heightened proliferation in MLRs with donor PBL, and all produced antidonor PBL antibody.

  15. Postnatal neurophysiologic effects of prenatal X-irradiation.

    PubMed

    Jensh, R P; Eisenman, L M; Brent, R L

    1995-02-01

    Histological and neurophysiological effects of in utero irradiation were examined following exposure of pregnant Wistar rat to 2.0 Gy X-irradiation or sham-irradiated on the 17th day of gestation. The 234 newborns were monitored for the age of appearance of four selected physiologic markers and the age of acquisition of five selected reflexes. Offspring were evaluated as young adults using selected behavioural tests. Postnatal growth was monitored weekly. Selected offspring were autopsied to determine the presence of morphologic central nervous system alterations. The results indicated that 2.0 Gy X-irradiation during the foetal period in rat gestation caused permanent alterations in the mature adult organism, which include non-recuperable growth retardation, morphologic changes in the brain such as microcephaly, abnormal cerebellar cortical cellular patterns, and alterations in the cell architecture of the hippocampus; diminished attainment of selected reflexes; alterations in the appearance of selected physiologic markers; and changes in adult test performance indicating significant hyperactivity among the irradiated offspring. Such exposure to X-irradiation during this period results in behavioural and morphologic alterations, which persist throughout life.

  16. Low-energy irradiation effects in cellulose

    SciTech Connect

    Polvi, Jussi; Nordlund, Kai

    2014-01-14

    Using molecular dynamics simulations, we determined the threshold energy for creating defects as a function of the incident angle for all carbon and oxygen atoms in the cellulose monomer. Our analysis shows that the damage threshold energy is strongly dependent on the initial recoil direction and on average slightly higher for oxygen atoms than for carbon atoms in cellulose chain. We also performed cumulative bombardment simulations mimicking low-energy electron irradiation (such as TEM imaging) on cellulose. Analyzing the results, we found that formation of free molecules and broken glucose rings were the most common forms of damage, whereas cross-linking and chain scission were less common. Pre-existing damage was found to increase the probability of cross-linking.

  17. The effects of celecoxib, a COX-2 selective inhibitor, on acute inflammation induced in irradiated rats.

    PubMed

    Khayyal, M T; El-Ghazaly, Mona A; El-Hazek, R M; Nada, A S

    2009-10-01

    The potential value of selective and non-selective COX-2 inhibitors in preventing some of the biochemical changes induced by ionizing radiation was studied in rats exposed to carrageenan-induced paw edema and 6-day-old air pouch models. The animals were exposed to different exposure levels of gamma-radiation, namely either to single doses of 2 and 7.5 Gy or a fractionated dose level of 7.5 Gy delivered as 0.5 Gy twice weekly for 7.5 weeks. The inflammatory response produced by carrageenan in irradiated rats was markedly higher than that induced in non-irradiated animals, and depended on the extent of irradiation. Celecoxib, a selective COX-2 inhibitor, in doses of 3, 5, 10, and 15 mg/kg was effective in reducing paw edema in irradiated and non-irradiated rats in a dose-dependent manner as well as diclofenac (3 mg/kg), a non-selective COX inhibitor. Irradiation of animals before the induction of the air pouch by an acute dose of 2 Gy led to a significant increase in leukocytic count, as well as in the level of interleukin-6 (IL-6), interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), LTB(4), PGE(2) (as an index of COX-2 activity), TXB(2) (as an index of COX-1 activity), and the plasma level of MDA. This increase in level of these parameters was more marked than that observed in the non-irradiated animals subjected to the inflammagen. The blood GSH level was not affected by the dose of irradiation used, whereas superoxide dismutase (SOD) activity was suppressed. In many respects, celecoxib (5 mg/kg) was as potent as diclofenac in decreasing the elevated levels of IL-6, IL-1beta, TNF-alpha, LTB(4), PGE(2), but lacked any significant effect on TXB(2) level. Since it is mostly selective for COX-2 with a rare effect on COX-1 enzyme, both drugs at the selected dose levels showed no effect on level of MDA, GSH, and SOD activity.

  18. Effect of ultra violet irradiation on the interplay between Th1 and Th2 lymphocytes

    PubMed Central

    Abo Elnazar, Salma Y.; Ghazy, Amany A.; Ghoneim, Hossam E.; Taha, Abdul-Rahman M.; Abouelella, Amira M.

    2015-01-01

    Although ultraviolet (UV) radiation is used to treat several types of diseases, including rickets, psoriasis, eczema, and jaundice, the prolonged exposure to its radiation may result in acute and chronic health effects particularly on the skin, eyes, and the immune system. Aim: This study was carried out to show the effect of UV on both of the lymphoproliferative response and their capacity to produce IL-12 and IL-10 in mice. Methods: Mice were exposed to whole body UVB and tested for the effect of recovery times on lymphocyte proliferation and cytokine production. In addition, direct irradiation of spleens and lymphocyte suspension was carried out. Basal and mitogens-stimulated lymphocyte proliferation was assessed by MTT assay while IL-10 and IL-12 were measured using ELISA. Results: There was a significant suppression in lymphocyte proliferation in comparison with control. IL-12 level was significantly reduced while the level of IL-10 was increased. Con A and PWM mitogens had no significant changes in IL-10 while Con A caused a highly significant increase in IL-12 at day 6 of recovery in UVB body irradiation. Conclusion: Exposure to UVB radiation could cause a state of immune suppression and shifts Th1/Th2 cell response. This effect is closely associated with the reduction of Th1 cytokines’ expression and increase in Th2 cytokines’ levels. PMID:25852558

  19. Effect of helium on irradiation creep behavior of B-doped F82H irradiated in HFIR

    DOE PAGES

    Ando, M.; Nozawa, Takashi; Hirose, Takanori; ...

    2015-07-30

    The diameter of pressurized tubes of F82H and B-doped F82H irradiated up to similar to 6 dpa have been measured by a non-contacting laser profilometer. The irradiation creep strains of F82H irradiated at 573 and 673K were almost linearly dependent on the effective stress level for stresses below 260 MPa and 170 MPa, respectively. The creep strain of (BN)-B-10-F82H was similar to that of F82H IEA at each effective stress level except 294 MPa at 573K irradiation. For 673K irradiation, the creep strain of some (BN)-B-10-F82H tubes was larger than that of F82H tubes. However, the generation of similar tomore » 300 appm He did not cause a large difference in the irradiation creep behavior at 6 dpa.« less

  20. Effect of helium on irradiation creep behavior of B-doped F82H irradiated in HFIR

    SciTech Connect

    Ando, M.; Nozawa, Takashi; Hirose, Takanori; Tanigawa, H.; Wakai, E.; Stoller, Roger E; Myers, Janie

    2015-07-30

    The diameter of pressurized tubes of F82H and B-doped F82H irradiated up to similar to 6 dpa have been measured by a non-contacting laser profilometer. The irradiation creep strains of F82H irradiated at 573 and 673K were almost linearly dependent on the effective stress level for stresses below 260 MPa and 170 MPa, respectively. The creep strain of (BN)-B-10-F82H was similar to that of F82H IEA at each effective stress level except 294 MPa at 573K irradiation. For 673K irradiation, the creep strain of some (BN)-B-10-F82H tubes was larger than that of F82H tubes. However, the generation of similar to 300 appm He did not cause a large difference in the irradiation creep behavior at 6 dpa.

  1. Comparative effects of neutron irradiation and X irradiation on the embryonic development of the rat

    SciTech Connect

    Solomon, H.M. ); Beckman, D.A.; Buck, S.J.; Brent, R.L. Thomas Jefferson Univ., Philadelphia, PA ); Gorson, R.O. ); Mills, R.E. )

    1994-02-01

    Our aim was to compare the dose-response relationship for the embryotoxic effects of 0.43 MeV neutrons with those of 240 kVp X rays after in utero exposures during early organogenesis in the rat. At 9.5 days after conception, pregnant rats were exposed to 0.025 to 0.35 Gy 0.43 MeV neutrons at a dose rate of 0.04 to 0.07 Gy/h. Comparable biological effects were produced using 0.50 to 2.05 Gy 240 kVp X rays. Neutron irradiation produced a greater proportion of offspring with very low body weight than with malformations when compared to X rays. There were no embryotoxic effects observed at neutron exposures of 0.025, 0.049, 0.079, 0.10, 0.15, and 0.20 Gy or X-ray exposures of 0.50 and 0.96 Gy. Taken together, the results suggest that the mechanisms by which neutron irradiation affects embryonic development may, in part, be both quantitatively and qualitatively different from those by which X irradiation affects development. These results support the generalization that the embryo exhibits a nonlinear response to increasing doses of ionizing radiations during the period of early organogenesis. 25 refs., 3 tabs.

  2. The calpain-suppressing effects of olesoxime in Huntington's disease.

    PubMed

    Weber, Jonasz J; Ortiz Rios, Midea M; Riess, Olaf; Clemens, Laura E; Nguyen, Huu P

    2016-01-01

    Olesoxime, a small molecule drug candidate, has recently attracted attention due to its significant beneficial effects in models of several neurodegenerative disorders including Huntington's disease. Olesoxime's neuroprotective effects have been assumed to be conveyed through a direct, positive influence on mitochondrial function. In a long-term treatment study in BACHD rats, the latest rat model of Huntington's disease, olesoxime revealed a positive influence on mitochondrial function and improved specific behavioral and neuropathological phenotypes. Moreover, a novel target of the compound was discovered, as olesoxime was found to suppress the activation of the calpain proteolytic system, a major contributor to the cleavage of the disease-causing mutant huntingtin protein into toxic fragments, and key player in degenerative processes in general. Results from a second model of Huntington's disease, the Hdh (Q111) knock-in mouse, confirm olesoxime's calpain-suppressing effects and support the therapeutic value of olesoxime for Huntington's disease and other disorders involving calpain overactivation.

  3. Effect of extracorporeal ultraviolet blood irradiation on blood cholesterol level

    NASA Astrophysics Data System (ADS)

    Zalesskaya, G. A.; Laskina, O. V.; Mitkovskaya, N. P.; Kirkovsky, V. V.

    2012-07-01

    We have studied the effect of extracorporeal ultraviolet blood irradiation on cholesterol metabolism in patients with cardiovascular diseases. We have carried out a comprehensive analysis of the spectral characteristics of blood and plasma, gas-exchange and oximetry parameters, and the results of a complete blood count and chemistry panel before and after UV blood irradiation. We have assessed the changes in concentrations of cholesterols (total cholesterol, low-density lipoprotein (LDL) cholesterol, triglycerides) in the blood of the patients in response to a five-day course of UV blood irradiation. The changes in the spectral characteristics of blood and plasma, the chemistry panel, the gas composition, and the fractional hemoglobin composition initiated by absorption of UV radiation are used to discuss the molecular mechanisms for the effect of therapeutic doses of UV radiation on blood cholesterols.

  4. Neutron and gamma irradiation effects on power semiconductor switches

    NASA Technical Reports Server (NTRS)

    Schwarze, G. E.; Frasca, A. J.

    1990-01-01

    The performance characteristics of high-power semiconductor switches subjected to high levels of neutron fluence and gamma dose must be known by the designer of the power conditioning, control and transmission subsystem of space nuclear power systems. Location and the allowable shielding mass budget will determine the level of radiation tolerance required by the switches to meet performance and reliability requirements. Neutron and gamma ray interactions with semiconductor materials and how these interactions affect the electrical and switching characteristics of solid state power switches is discussed. The experimental measurement system and radiation facilities are described. Experimental data showing the effects of neutron and gamma irradiation on the performance characteristics are given for power-type NPN Bipolar Junction Transistors (BJTs), and Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs). BJTs show a rapid decrease in gain, blocking voltage, and storage time for neutron irradiation, and MOSFETs show a rapid decrease in the gate threshold voltage for gamma irradiation.

  5. Gastroprotective effect of kefir on ulcer induced in irradiated rats.

    PubMed

    Fahmy, Hanan A; Ismail, Amel F M

    2015-03-01

    The current study was designed to investigate the protective effect of kefir milk on ethanol-induced gastric ulcers in γ-irradiated rats. The results of the present study revealed that treatment with γ-irradiation and/or ethanol showed a significant increase in ulcers number, total acidity, peptic, H(+)K(+)ATPase, MMP-2 and MMP-9 activities and MDA level, which were accompanied by a significant decrease in the mucus content, the stomach GSH level, the GSH-Px activity and DNA damage. Pre-treatment with kefir milk exert significant improvement in all the tested parameters. Kefir milk exerts comparable effect to that of the antiulcer drug ranitidine. In conclusion, the present study revealed that oral administration of kefir milk prevents ethanol-induced gastric ulcer in γ-irradiated rats that could attribute to its antioxidant, anti-apoptotic and radio-protective activities.

  6. Neutron and gamma irradiation effects on power semiconductor switches

    NASA Technical Reports Server (NTRS)

    Schwarze, G. E.; Frasca, A. J.

    1990-01-01

    The performance characteristics of high power semiconductor switches subjected to high levels of neutron fluence and gamma dose must be known by the designer of the power conditioning, control and transmission subsystem of space nuclear power systems. Location and the allowable shielding mass budget will determine the level of radiation tolerance required by the switches to meet performance and reliability requirements. Neutron and gamma ray interactions with semiconductor materials and how these interactions affect the electrical and switching characteristics of solid state power switches is discussed. The experimental measurement system and radiation facilities are described. Experimental data showing the effects of neutron and gamma irradiation on the performance characteristics are given for power-type NPN Bipolar Junction Transistors (BJTs), and Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs). BJTs show a rapid decrease in gain, blocking voltage, and storage time for neutron irradiation, and MOSFETs show a rapid decrease in the gate threshold voltage for gamma irradiation.

  7. [Effect of irradiation on the degradation of rat thymocyte chromatin].

    PubMed

    Tsudzevich, B O; Parkhomets', Iu P; Andriĭchuk, T R; Iurkina, V V

    1998-01-01

    Genome instability of adaptive nature is formed under the experimental influence on a cell. Under critical conditions, strategy of organism is to damage the cells that cannot be restored and controlled by including the program of apoptosis. The ordered internucleosomal DNA degradation is considered to be one of the proof attributes of immunocompetent cell apoptosis. We investigated the effects of various doses of irradiation on the thymocytes chromatine fragmentation in 1,2,3 hours after a single X-ray exposure or after chronic influence in conditions of Chernobyl research base. By the means of electrophoresis in agarose and judging by polydeoxyribonucleotides accumulation we observed the "ladder pattern" of degradation in 3 hr after single 1 Gr irradiation (the smallest dose displaying the effect). We suppose that the influence of both chronic low-intensity irradiation taking place in Chernobyl and single X-ray exposure result in intensifying of DNA fragmentation in the cells of immunocompetent organs.

  8. Teratogenic effect of californium-252 irradiation in rats.

    PubMed

    Satow, Y; Lee, J Y; Hori, H; Okuda, H; Tsuchimoto, S; Sawada, S; Yokoro, K

    1989-06-01

    The teratogenicity of californium-252 (Cf-252) irradiation which generates approximately 70% 2.3 MeV fast neutron and 30% gamma rays was evaluated. A single whole body exposure of Cf-252 at various doses was given to pregnant rats on day 8 or 9 of pregnancy, followed by microscopic autopsy of the fetuses at the terminal stage of pregnancy to search for external and internal malformations. For comparison, pregnant rats were irradiated with various doses of cobalt-60 (Co-60) standard gamma rays at the same dose rate (1 rad/min.). The doses were 20-120 rad of Cf-252 and 80-220 rad of Co-60. Using frequency of radiation induced malformations observed on day 8 of pregnancy as an index, relative biological effectiveness (RBE) of 2.3-2.7 was obtained from the straight line obtained by modifying by the least squares method the frequency curves of malformed fetuses in total implants and in surviving fetuses. The types of malformations induced by Cf-252 and Co-60 irradiation were alike. Using fetal LD50 as an index, 2.4 was obtained as RBE when irradiated on day 8 of pregnancy and 3.1 as that when irradiated on day 9. The results showed that Cf-252 had stronger a teratogenic effect than Co-60 gamma rays.

  9. BARKHAUSEN EFFECT IN IRRADIATED PURE IRON AND NICKEL.

    DTIC Science & Technology

    The effect of electron and neutron irradiation on the Barkhausen effect and coercive force of pure iron and nickel were investigated. The...investigation was designed to establish whether (l) the Barkhausen effect can provide a sensitive indication of the presence of large radiation-induced defect...clusters and whether (2) study of the Barkhausen effect could provide meaningful information about behavior of such defects. (These aims were based on

  10. Molecular Mechanisms for Sweet-suppressing Effect of Gymnemic Acids*

    PubMed Central

    Sanematsu, Keisuke; Kusakabe, Yuko; Shigemura, Noriatsu; Hirokawa, Takatsugu; Nakamura, Seiji; Imoto, Toshiaki; Ninomiya, Yuzo

    2014-01-01

    Gymnemic acids are triterpene glycosides that selectively suppress taste responses to various sweet substances in humans but not in mice. This sweet-suppressing effect of gymnemic acids is diminished by rinsing the tongue with γ-cyclodextrin (γ-CD). However, little is known about the molecular mechanisms underlying the sweet-suppressing effect of gymnemic acids and the interaction between gymnemic acids versus sweet taste receptor and/or γ-CD. To investigate whether gymnemic acids directly interact with human (h) sweet receptor hT1R2 + hT1R3, we used the sweet receptor T1R2 + T1R3 assay in transiently transfected HEK293 cells. Similar to previous studies in humans and mice, gymnemic acids (100 μg/ml) inhibited the [Ca2+]i responses to sweet compounds in HEK293 cells heterologously expressing hT1R2 + hT1R3 but not in those expressing the mouse (m) sweet receptor mT1R2 + mT1R3. The effect of gymnemic acids rapidly disappeared after rinsing the HEK293 cells with γ-CD. Using mixed species pairings of human and mouse sweet receptor subunits and chimeras, we determined that the transmembrane domain of hT1R3 was mainly required for the sweet-suppressing effect of gymnemic acids. Directed mutagenesis in the transmembrane domain of hT1R3 revealed that the interaction site for gymnemic acids shared the amino acid residues that determined the sensitivity to another sweet antagonist, lactisole. Glucuronic acid, which is the common structure of gymnemic acids, also reduced sensitivity to sweet compounds. In our models, gymnemic acids were predicted to dock to a binding pocket within the transmembrane domain of hT1R3. PMID:25056955

  11. Irradiation effects on magnetic properties in neutron and proton irradiated reactor pressure vessel steel

    SciTech Connect

    Park, D.G.; Hong, J.H.; Kim, I.S.; Kim, H.C.

    1999-09-01

    The effects of neutron and proton dose on the magnetic properties of a reactor pressure vessel (RPV) steel were investigated. The coercivity and maximum induction increased in two stages with respect to neutron dose, being nearly constant up to a dose of 1.5 x 10{sup {minus}7} dpa, followed by a rapid increase up to a dose of 1.5 x 10{sup {minus}5} dpa. The coercivity and maximum induction in the proton irradiated specimens also showed a two stage variation with respect to proton dose, namely a rapid increase up to a dose of 0.2 x 10{sup {minus}2} dpa, then a decrease up to 1.2 x 10{sup {minus}2} dpa. The Barkhausen noise (BN) amplitude in neutron irradiated specimens also varied in two stages in a reverse manner, the transition at the same dose of 1.5 x 10{sup {minus}7} dpa. The BN amplitude in proton irradiated specimens decreased by 60% up to 0.2 x 10{sup {minus}2} dpa followed by an increase up to 1.2 x 10{sup {minus}2} dpa. The results were in good accord with the one dimensional domain wall model considering the density of defects and wall energy.

  12. Suppressive effect of microRNA-143 in retinoblastoma

    PubMed Central

    Wang, Li-Lun; Hu, Hai-Feng; Feng, Yan-Qin

    2016-01-01

    AIM To investigate microRNA-143 expression and effect on suppression of retinoblastoma (RB) cells. METHODS The expression of microRNA-143 was investigated and compared in normal human retina tissue samples and in RB cell lines of Y79 and Weri1. The microRNA-143 mimics were transfected into the RB cell lines separately, and its effect on RB cell lines was detected using reverse-transcription quantitative polymerase chain reaction and Western blotting methods. RESULTS The microRNA-143 expression was significantly suppressed in RB cell lines. Overexpression of microRNA-143 significantly lowered cell viability and invasion of the RB cell lines, and increased the number of apoptotic cells. Meanwhile, the Bax expression was up-regulated and much higher in the microRNA-143 mimics transfected group than that in the negative control and the microRNA-143 inhibitor groups. CONCLUSION MicroRNA-143 exhibits suppressive effects in RB. The current study provides the perspective of a potential therapeutic treatment for RB. PMID:27990360

  13. Effects of helium-neon laser irradiation and local anesthetics on potassium channels in pond snail neurons.

    PubMed

    Ignatov, Yu D; Vislobokov, A I; Vlasov, T D; Kolpakova, M E; Mel'nikov, K N; Petrishchev, I N

    2005-10-01

    Intracellular dialysis and membrane voltage clamping were used to show that He-Ne laser irradiation of a pond snail neuron at a dose of 0.7 x 10(-4) J (power density 1.5 x 10(2) W/m2) increases the amplitude of the potential-dependent slow potassium current, while a dose of 0.7 x 10(-3) J decreases this current. Bupivacaine suppresses the potassium current. Combined application of laser irradiation at a dose of 0.7 x 10(-3) J increased the blocking effect of 10 microM bupivacaine on the slow potassium current, while an irradiation dose of 0.7 x 10(-4) J weakened the effect of bupivacaine.

  14. Helium effects on irradiation dmage in V alloys

    SciTech Connect

    Doraiswamy, N.; Alexander, D.

    1996-10-01

    Preliminary investigations were performed on V-4Cr-4Ti samples to observe the effects of He on the irradiation induced microstructural changes by subjecting 3 mm electropolished V-4Cr-4Ti TEM disks, with and without prior He implantation, to 200 keV He irradiation at room temperature and monitoring, in-situ, the microstructural evolution as a function of total dose with an intermediate voltage electron microscope directly connected to an ion implanter. A high density of black dot defects were formed at very low doses in both He pre-implanted and unimplanted samples.

  15. Effect of solar irradiation on extracellular enzymes of Aeromonas proteolytica

    NASA Technical Reports Server (NTRS)

    Foster, B. G.

    1973-01-01

    The bacterium Aeromonas proteolytica was selected for studying the effects of solar irradiation on extracellular enzymes because it produces an endopeptidase that is capable of degrading proteins and a hemolysin that is active in lysing human erythrocytes. Possible alterations in the rate of enzyme production in response to the test conditions are currently underway and are not available for this preliminary report. Completed viability studies are indicative that little difference exists among the survival curves derived for cells exposed to various components of ultraviolet irradiation in space.

  16. Effects of self-irradiation in plutonium alloys

    DOE PAGES

    Chung, B. W.; Lema, K. E.; Allen, P. G.

    2015-09-16

    In this paper, we present updated results of self-irradiation effects on 238Pu-enriched 239Pu alloys measured by immersion density, dilatometry, and tensile tests. We obtained the self-irradiation equivalent time of nearly 200 years, nearly 100 years longer than in our previous papers. At this extended aging, we find the rate of decrease in density has slowed significantly, stabilizing around 15.73 g/cc, without signs of void swelling. The volume expansion measured at 35°C also shows apparent saturation at less than 0.25%. Quasi-static tensile measurement still show gradual increase in the strength of plutonium alloys with age.

  17. Effects of irradiation on alaryngeal voice of totally laryngectomized patients

    SciTech Connect

    Izdebski, K.; Fontanesi, J.; Ross, J.C.; Hetzler, D.

    1988-06-01

    The effects of radiation therapy on the ability of totally laryngectomized patients to produce voice and speech were examined using objective non-invasive methods. Moderate to severe losses were noted in patients producing voice with all types of alaryngeal modalities: tracheoesophageal, esophageal, and electrolaryngeal. Voice and speech losses were related to the impaired motility and vibratory capability of the esophageal wall and mucosa, to fibrosis of the submandibular region and to trismus. Tracheoesophageal and esophageal voice was recovered some weeks after completion of irradiation. No voice losses were observed in alaryngeal speakers who did not undergo voice restoration until after irradiation. All irradiated patients also showed various degrees of dysphagia during the treatment.

  18. Effects of laser irradiation on the morphology of Cu(110)

    SciTech Connect

    Brandstetter, T.; Draxler, M.; Hohage, M.; Zeppenfeld, P.; Stehrer, T.; Heitz, J.; Georgiev, N.; Martinotti, D.; Ernst, H.-J.

    2008-07-15

    The effects of pulsed laser irradiation on the morphology of the Cu(110) surface were investigated by means of reflectance difference spectroscopy (RDS) and spot profile analysis low-energy electron diffraction (SPA-LEED). The laser light induces surface defects (adatoms and islands) as well as subsurface dislocation lines. The high surface mobility leads to efficient annealing of the surface defects even at room temperature, whereas the subsurface dislocation lines persist up to temperatures T>800 K. SPA-LEED profiles of the (00) diffraction spot from the laser irradiated surface suggest an anisotropic distribution of the subsurface line defects related to the geometry of the fcc easy glide system, which is corroborated by STM measurements. Comparative experiments using conventional Ar ion bombardment point out the distinctiveness of the morphological changes induced by laser irradiation.

  19. Mn(III) meso-tetrakis-(N-ethylpyridinium-2-yl) porphyrin mitigates total body irradiation-induced long-term bone marrow suppression.

    PubMed

    Li, Hongliang; Wang, Yong; Pazhanisamy, Senthil K; Shao, Lijian; Batinic-Haberle, Ines; Meng, Aimin; Zhou, Daohong

    2011-07-01

    Our recent studies showed that total body irradiation (TBI) induces long-term bone marrow (BM) suppression in part by induction of hematopoietic stem cell (HSC) senescence through reactive oxygen species (ROS). In this study, we examined if Mn(III) meso-tetrakis-(N-ethylpyridinium-2-yl) porphyrin (MnTE), a superoxide dismutase mimetic and potent antioxidant, can mitigate TBI-induced long-term BM injury in a mouse model. Our results showed that post-TBI treatment with MnTE significantly inhibited the increases in ROS production and DNA damage in HSCs and the reduction in HSC frequency and clonogenic function induced by TBI. In fact, the clonogenic function of HSCs from irradiated mice after MnTE treatment was comparable to that of HSCs from normal controls on a per-HSC basis, suggesting that MnTE treatment inhibited the induction of HSC senescence by TBI. This suggestion is supported by the finding that MnTE treatment also reduced the expression of p16(Ink4a) (p16) mRNA in HSCs induced by TBI and improved the long-term and multilineage engraftment of irradiated HSCs after transplantation. Therefore, the results from this study demonstrate that MnTE has the potential to be used as a therapeutic agent to mitigate TBI-induced long-term BM suppression by inhibiting ionizing radiation-induced HSC senescence through the ROS-p16 pathway.

  20. The NMR investigation of the electromagnetic irradiation effects on bacteria

    NASA Astrophysics Data System (ADS)

    Drokina, T. V.; Lisin, V. V.; Popova, L. U.; Balandina, A. N.; Bitekhtina, M. A.

    2006-12-01

    The luminous marine bacteria (Photobacterium leiognathi, strain 54) are influenced by a nonthermal-intensity millimeter electromagnetic field, which was studied by nuclear magnetic resonance (NMR). It is shown that the proton spectrum of luminous bacteria depends on the electromagnetic irradiation effect (v = 42.2 GHz).

  1. Effects of light exposure on irradiated barium fluoride crystals

    SciTech Connect

    Wuest, C.R.; Mauger, G.J.

    1993-04-20

    Small barium fluoride crystals have been irradiated using cobalt-60 gamma rays under various illumination conditions to establish the effect of photo-bleaching of the radiation-induced color centers. This paper describes results of a few different experiments conducted at LLNL over the past few weeks.

  2. Degradation of Nylon 6,6 Fire-Suppression Casing from Plutonium Glove Boxes Under Alpha and Neutron Irradiation

    DOE PAGES

    Millsap, Donald W.; Cournoyer, Michael E.; Landsberger, Sheldon; ...

    2015-04-23

    Nylon 6,6 tensile specimens, conforming to the casing for self-contained fire extinguisher systems, have been irradiated using both an accelerator He++ ion beam and a 5-Ci PuBe neutron source to model the radiation damage these systems would likely incur over a lifetime of operation within glove boxes. Following irradiation, these samples were mechanically tested using standard practices as described in ASTM D638. The results of the He++ study indicate that the tensile strength of the nylon specimens undergoes some slight (<10%) degradation while other properties of the samples, such as elongation and tangent modulus, appear to fluctuate with increasing dosemore » levels. The He++-irradiated specimens also have a noticeable level of discoloration corresponding to increasing levels of dose. The neutron-irradiated samples show a higher degree of mechanical degradation than the He++-irradiated samples.« less

  3. Degradation of Nylon 6,6 Fire-Suppression Casing from Plutonium Glove Boxes Under Alpha and Neutron Irradiation

    SciTech Connect

    Millsap, Donald W.; Cournoyer, Michael E.; Landsberger, Sheldon; Tesmer, Joseph R.; Wang, Matthew Y.

    2015-04-23

    Nylon 6,6 tensile specimens, conforming to the casing for self-contained fire extinguisher systems, have been irradiated using both an accelerator He++ ion beam and a 5-Ci PuBe neutron source to model the radiation damage these systems would likely incur over a lifetime of operation within glove boxes. Following irradiation, these samples were mechanically tested using standard practices as described in ASTM D638. The results of the He++ study indicate that the tensile strength of the nylon specimens undergoes some slight (<10%) degradation while other properties of the samples, such as elongation and tangent modulus, appear to fluctuate with increasing dose levels. The He++-irradiated specimens also have a noticeable level of discoloration corresponding to increasing levels of dose. The neutron-irradiated samples show a higher degree of mechanical degradation than the He++-irradiated samples.

  4. Occipital TMS has an activity-dependent suppressive effect

    PubMed Central

    Perini, Francesca; Cattaneo, Luigi; Carrasco, Marisa; Schwarzbach, Jens V.

    2012-01-01

    The effects of transcranial magnetic stimulation (TMS) vary depending on the brain state at the stimulation moment. Four mechanisms have been proposed to underlie these effects: (i) virtual lesion–TMS suppresses neural signals; (ii) preferential activation of less active neurons–TMS drives up activity in the stimulated area, but active neurons are saturating, (iii) noise generation–TMS adds random neuronal activity and its effect interacts with stimulus-intensity; (iv) noise generation–TMS adds random neuronal activity and its effect depends on TMS-intensity. Here we explore these hypotheses by investigating the effects of TMS on early visual cortex on the contrast response function while varying adaptation state of the observers. We tested human participants in an orientation discrimination task, in which performance is contingent upon contrast sensitivity. Before each trial, neuronal activation of visual cortex was altered through contrast adaptation to two flickering gratings. In a factorial design, with or without adaptation, a single TMS pulse was delivered simultaneously with targets of varying contrast. Adaptation decreased contrast sensitivity. The effect of TMS on performance was state-dependent: TMS decreased contrast sensitivity in the absence of adaptation but increased it after adaptation. None of the proposed mechanisms can account for the results in their entirety, in particular, for the facilitatory effect at intermediate to high contrasts after adaptation. We propose an alternative hypothesis: TMS effects are activity-dependent, so that TMS suppresses the most active neurons and thereby changes the balance between excitation and inhibition. PMID:22956826

  5. Effects of low-power laser irradiation on the mitosis rate of the corneal epithelium

    NASA Astrophysics Data System (ADS)

    Chen, Varda; Landshman, Nahum; Belkin, Michael

    1995-05-01

    The effect of repeated low power He-Ne laser on rabbit's corneal epithelium was studied after 3 daily sessions. Under certain irradiation parameters, low power He-Ne laser irradiation was found to change the mitotic rate in the basal layer of intact corneal epithelium. Three daily irradiations for 3 or 10 minutes increased the mitotic index while 30 minutes irradiations decreased it.

  6. Effects of vacuum fluctuation suppression on atomic decay rates

    SciTech Connect

    Ford, L.H.; Roman, Thomas A.

    2011-08-15

    Highlights: > Excited atoms are shot through a cavity containing an electromagnetic field. > Cavity is in the lowest mode in a non-classical state. > Such a state can suppress the decay rate of the atoms in certain situations. > We show that this effect can be correlated with periods of negative energy density. - Abstract: The use of atomic decay rates as a probe of sub-vacuum phenomena will be studied. Because electromagnetic vacuum fluctuations are essential for radiative decay of excited atomic states, decay rates can serve as a measure of the suppression of vacuum fluctuations in non-classical states, such as squeezed vacua. In such states, the renormalized expectation value of the square of the electric field or the energy density can be periodically negative, representing suppression of vacuum fluctuations. We explore the extent to which atomic decays can be used to measure the mean squared electric field or energy density. We consider a scheme in which atoms in an excited state transit a closed cavity whose lowest mode contains photons in a non-classical state. A crucial feature of our analysis is that we do not employ the rotating wave approximation. The change in the decay probability of the atom in the cavity due to the non-classical state can, under certain circumstances, serve as a measure of the mean squared electric field or energy density in the cavity. We make some estimates of the magnitude of this effect, which indicate that an experimental test might be possible, although very challenging.

  7. The effect of essential oil formulations for potato sprout suppression.

    PubMed

    Owolabi, Moses S; Lajide, Labunmi; Oladimeji, Matthew O; Setzer, William N

    2010-04-01

    The concerns over safety and environmental impact of synthetic pesticides such as chlorpropham (CIPC) has stimulated interest in finding environmentally benign, natural sprout suppressants, including essential oils. The effects of Chenopodium ambrosioides and Lippia multiflora essential oils on sprout growth and decay of stored potatoes has been investigated. Formulations of essential oils with alumina, bentonite, or kaolin, both with and without Triton X-100 additive, were tested. These formulations have been compared to the pulverized plant materials themselves as well as wick-volatilized essential oils. The results showed that the tested oils possess compositions that make them suitable for application as sprout suppressants. Additionally, the formulation seems to be able to reduce the volatility of the essential oil and artificially extend dormancy of stored potatoes.

  8. Effect of low power laser irradiation on macrophage phagocytic capacity

    NASA Astrophysics Data System (ADS)

    Lu, Cuixia; Song, Sheng; Tang, Yu; Zhou, Feifan

    2011-03-01

    Phagocytosis and subsequent degradation of pathogens by macrophages play a pivotal role in host innate immunity in mammals. Laser irradiation has been found to produce photobiological effects with evidence of interference with immunological functions. However, the effects of laser on the immune response have not been extensively characterized. In this study, we focused our attention on the effects of He-Ne laser on the phagocytic activity of macrophages by using flow cytometry (FCM). After irradiating at fluence of 0, 1, 2 J/cm2 with He-Ne laser (632.8 nm, 3mw), the cells were incubated with microsphere and then subjected to FACS analysis. The results showed that Low-power laser irradiation (LPLI) leads to an increase in phagocytosis on both mouse peritoneal macrophages and the murine macrophage-like cell line RAW264.7. In addition, we demonstrated that LPLI increased phagocytosis of microsphere in a dose-dependent manner, reaching a maximum at fluence of 2 J/cm2. Taken together, our results indicated that Low-power laser irradiation with appropriate dosage can enhance the phagocytosis of macrophage, and provided a theoretical base for the clinical use of the He-Ne laser.

  9. Bystander Effects Induced by Medium From Irradiated Cells: Similar Transcriptome Responses in Irradiated and Bystander K562 Cells

    SciTech Connect

    Herok, Robert; Konopacka, Maria; Polanska, Joanna; Swierniak, Andrzej; Rogolinski, Jacek; Jaksik, Roman; Hancock, Ronald; Rzeszowska-Wolny, Joanna

    2010-05-01

    Purpose: Cells exposed to ionizing radiation release factors that induce deoxyribonucleic acid damage, chromosomal instability, apoptosis, and changes in the proliferation rate of neighboring unexposed cells, phenomena known as bystander effects. This work analyzes and compares changes in global transcript levels induced by direct irradiation and by bystander effects in K562 (human erythroleukemia) cells. Methods and Materials: Cells were X-irradiated with 4 Gy or transferred into culture medium collected from cells 1 h after irradiation (irradiation-conditioned medium). Global transcript profiles were assessed after 36 h of growth by use of Affymetrix microarrays (Affymetrix, Santa Clara, CA) and the kinetics of change of selected transcripts by quantitative reverse transcriptase-polymerase chain reaction. Results: The level of the majority (72%) of transcripts changed similarly (increase, decrease, or no change) in cells grown in irradiation-conditioned medium or irradiated, whereas only 0.6% showed an opposite response. Transcript level changes in bystander and irradiated cells were significantly different from those in untreated cells grown for the same amount of time and were confirmed by quantitative reverse transcriptase-polymerase chain reaction for selected genes. Signaling pathways in which the highest number of transcripts changed in both conditions were found in the following groups: neuroactive ligand-receptor, cytokine-cytokine receptor interaction, Janus Kinase-Signal Transducers and Activators of Transcription (JAK-STAT) and Mitogen-Activated Protein Kinase (MAPK) In control cells more transcripts were downregulated than in irradiated and bystander cells with transcription factors YBX1 and STAT5B, heat shock protein HSPA1A, and ribonucleic acid helicase DDX3X as examples. Conclusions: The transcriptomes of cells grown in medium from X-irradiated cells or directly irradiated show very similar changes. Signals released by irradiated cells may cause

  10. Effect of irradiation on stored vacuum packaged Wiltshire bacon

    NASA Astrophysics Data System (ADS)

    Dempster, JF; Halls, NA

    Wiltshire cured 'middle-cut' bacon (NaCl, 4.87%; 40 mg/kg NO 2; 53 mg/kg NO 3) was boned, sliced and vacuum packaged. It was irradiated (25 kGy: 10 kGy) and stored aerobically (5 0 : 15 0). At weekly intervals the bacon was evaluated bacteriologically and organoleptically (appearance, odour, colour of lean and fat) against unirradiated (control) samples). Results indicated that irradiation (10 kGy) did not permanently inhibit bacterial growth. After initial reductions in count of 0.99 g -1-1(15 0C) and log 3.61 g -1 (5 0C), maximum numbers were reached in 28 days at 15 0C (log 10.32 g -1) and in 35 days at 5 0C (log 8.05 g -1). However viability was significantly affected by 25 kGy irradiation: final numbers reached being log 2.22 g -1 (15 0C) at 35 days and log 3.38 g -1 (5 0C) at 42 days. Appearance and colour (fat and lean) were not significantly impaired by irradiation. However the interaction of storage temperature (5 0 : 15 0C), irradiation (10 kGy: 25 kGy): duration of storage (42 days) and initial count (log 7.24 g -1) had pronounced adverse effects on odour judgements. Evaluation of odour changes in bacon due to irradiation require further investigation. This is especially so since it is often possible to detect odour changes in raw meat after doses as low as 0.5 kGy (Coleby 1959).

  11. Various background pattern-effect on saccadic suppression.

    PubMed

    Mitrani, L; Radil-Weiss, T; Yakimoff, N; Mateeff, S; Bozkov, V

    1975-09-01

    It has been proved that the saccadic suppression is a phenomenon closely related to the presence of contours and structures in the visual field. Experiments were performed to clarify whether the structured background influences the pattern of attention distribution (making the stimulus detection more difficult) or whether the elevation of visual threshold is due to the "masking' effect of the moving background image over the retina. Two types of backgrounds were used therefore: those with symbolic meaning in the processing of which "psychological' mechanisms are presumably involved like picture reproductions of famous painters and photographs of nudes, and those lacking semantic significance like computer figures composed of randomly distributed black and white squares with different grain expressed as the entropy of the pattern. The results show that saccadic suppression is primarily a consequence of peripheral mechanisms, probably of lateral inhibition in the visual field occurring in the presence of moving edges over the retina. Psychological factors have to be excluded as being fundamental for saccadic suppression.

  12. Effect of recrystallization on ion-irradiation hardening and microstructural changes in 15Cr-ODS steel

    NASA Astrophysics Data System (ADS)

    Ha, Yoosung; Kimura, Akihiko

    2015-12-01

    The effects of recrystallization on ion-irradiation hardening and microstructural changes were investigated for a 15Cr-ODS ferritic steel. Dual ion-irradiation experiments were performed at 470 °C using 6.4 MeV Fe3+ ions simultaneously with energy-degraded 1 MeV He+ ions. The displacement of damage at 600 nm depth from the specimen surface was 30 dpa. Nano-indentation test with Berkovich type indentation tip was measured by constant stiffness measurement (CSM) technique. Results from nano-indentation tests indicate irradiation hardening in ODS steels even at 470 °C, while it wasn't observed in reduced activation ferritic steel. Recrystallized ODS steel shows a larger irradiation hardening, which is considered to be due to the reduction of grain boundaries and interfaces of matrix/oxide particles. In 20% cold rolled ODS steel after recrystallization, both the hardening and bubble number density were lower than those of recrystallized ODS steel, suggesting that dislocations generated by cold rolling suppress bubble formation. Based on the estimation of irradiation hardening from TEM observation results, it is considered that the bubbles are not the main factor controlling ion-irradiation hardening.

  13. Light irradiance and spectral distribution effects on cyanobacterial hydrogen production

    NASA Astrophysics Data System (ADS)

    Fatihah Salleh, Siti; Kamaruddin, Azlina; Hekarl Uzir, Mohamad; Rahman Mohamed, Abdul; Halim Shamsuddin, Abdul

    2016-03-01

    Light is an essential energy source for photosynthetic cyanobacteria. Changes in both light irradiance and spectral distribution will affect their photosynthetic productivity. Compared to the light irradiance, little investigations have been carried out on the effect of light spectra towards cyanobacterial hydrogen production. Hence, this work aims to investigate the effects of both light quantity and quality on biohydrogen productivity of heterocystous cyanobacterium, A.variabilis. Under white light condition, the highest hydrogen production rate of 31 µmol H2 mg chl a -1 h-1 was achieved at 70 µE m-2 s-1. When the experiment was repeated at the same light irradiance but different light spectra of blue, red and green, the accumulations of hydrogen were significantly lower than the white light except for blue light. As the light irradiance was increased to 350 µE m-2 s-1, the accumulated hydrogen under the blue light doubled that of the white light. Besides that, an unusual prolongation of the hydrogen production up to 120 h was observed. The results obtained suggest that blue light could be the most desirable light spectrum for cyanobacterial hydrogen production.

  14. The effects of professional irradiation, fields of research, results

    SciTech Connect

    Okladnikova, N.D.; Pesternikova, V.S.; Sumina, M.V.

    1993-12-31

    Main results of research of after effects of professional irradiation of the personnel of the first atomic power industry enterprise in the country ({open_quotes}Mayak{close_quotes}) are presented. The earliest determinated effects (chronic and acute radiation sickness, local radiation traumae, plutonium pneumosclerosis) and the late effects of external gamma-irradiation and combined (pu-239, tritium) radiation effect in a wide range of doses have been studied. The basis of the paper are the results of a complex medical research of the personnel: the state of haemopoietic, nerve, cardiovascular systems, alimentary canal, other organs and systems, immunity, somatic cells genome and the frequency of tumor and non-tumor diseases. The observation and research period covered is 40 years from the first contact with the ionized radiation source.

  15. Neutron irradiation effects on high Nicalon silicon carbide fibers

    SciTech Connect

    Osborne, M.C.; Steiner, D.; Snead, L.L.

    1996-10-01

    The effects of neutron irradiation on the mechanical properties and microstructure of SiC and SiC-based fibers is a current focal point for the development of radiation damage resistant SiC/SiC composites. This report discusses the radiation effects on the Nippon Carbon Hi-Nicalon{trademark} fiber system and also discusses an erratum on earlier results published by the authors on this material. The radiation matrix currently under study is also summarized.

  16. Overexpression of phospholipid-hydroperoxide glutathione peroxidase in human dermal fibroblasts abrogates UVA irradiation-induced expression of interstitial collagenase/matrix metalloproteinase-1 by suppression of phosphatidylcholine hydroperoxide-mediated NFkappaB activation and interleukin-6 release.

    PubMed

    Wenk, Jutta; Schüller, Jutta; Hinrichs, Christina; Syrovets, Tatjana; Azoitei, Ninel; Podda, Maurizio; Wlaschek, Meinhard; Brenneisen, Peter; Schneider, Lars-A; Sabiwalsky, Andrea; Peters, Thorsten; Sulyok, Silke; Dissemond, Joachim; Schauen, Matthias; Krieg, Thomas; Wirth, Thomas; Simmet, Thomas; Scharffetter-Kochanek, Karin

    2004-10-29

    Phospholipid-hydroperoxide glutathione peroxidase (PHGPx) exhibits high specific activity in reducing phosphatidylcholine hydroperoxides (PCOOHs) and thus may play a central role in protecting the skin against UV irradiation-triggered detrimental long term effects like cancer formation and premature skin aging. Here we addressed the role of PHGPx in the protection against UV irradiation-induced expression of matrix metalloproteinase-1 (MMP-1). For this purpose, we created human dermal fibroblast cell lines overexpressing human PHGPx. Overexpression led to a significant increase in PHGPx activity. In contrast to a maximal 4.5-fold induction of specific MMP-1 mRNA levels in vector-transfected cells at 24 h after UVA irradiation, no MMP-1 induction occurred at any studied time point after UVA treatment of PHGPx-overexpressing fibroblasts. As interleukin-6 (IL-6) was earlier shown to mediate the UVA induction of MMP-1, we studied whether PHGPx overexpression might interfere with the NFkappaB-mediated IL-6 induction and downstream signaling. Using transient transfections of IL-6 promoter constructs containing NFkappaB binding sites, we observed a high induction of the reporter gene luciferase in vector-transfected control cells and a significantly lower induction in PHGPx-overexpressing fibroblasts following UVA irradiation. Consistently both UVA irradiation and treatment of fibroblasts with PCOOHs led to phosphorylation and nuclear translocation of the p65 subunit, whereas cells overexpressing PHGPx exhibited impaired NFkappaB activation, p65 phosphorylation, and nuclear translocation. In line with this, the PHGPx-overexpressing fibroblasts showed a reduced constitutive and UVA irradiation-induced IL-6 release. After incubating PHGPx-overexpressing cells with PCOOHs a reduced induction of IL-6 was observed. This together with the suppression of UVA irradiation-induced IL-6 release in the presence of Trolox, a chain breaker of PCOOH-initiated lipid peroxidation

  17. Effects of neutron irradiation on microstructure and mechanical properties of carbon/carbon composites

    NASA Astrophysics Data System (ADS)

    Hamada, K.; Sato, S.; Kohyama, A.

    1994-09-01

    As an important part of the national R&D program to high performance and low cost {C}/{C} composite materials, a new manufacturing method of {C}/{C} composite with densified matrix without conventional densification process has been successfully developed. In this study, neutron irradiation effects on mechanical properties of the innovative {C}/{C} composites were examined. Materials used were one- and two-directionally reinforced composites with mesophase-pitch based carbon fibers as reinforcement and the mixture of green coke and phenolic resin as matrix precursor. Neutron irradiation was performed to 1.3 × 10 21 and 1.5 × 10 22 n/m 2 ( E > 1 MeV) at about 350 K. Mechanical properties were measured by bend tests. Flexural and shear strength were increased with increasing neutron fluence. On the contrary, fracture strain showed quite a little dependence on neutron fluence. Flexural modulus at near 0 strain was increased with increasing fluence. Stress stiffening at near 0 strain was suppressed with irradiation, while modulus drop was observed at high strain region and decreased with increasing neutron fluence. These results were interpreted in terms of microstructural change.

  18. Irradiation effect on deuterium behaviour in low-dose HFIR neutron-irradiated tungsten

    SciTech Connect

    Shimada, Masashi; Cao, G.; Otsuka, T.; Hara, M.; Kobayashi, M.; Oya, Y.; Hatano, Y.

    2014-12-01

    Tungsten samples were irradiated by neutrons in the High Flux Isotope Reactor, Oak Ridge National Laboratory at reactor coolant temperatures of 50-70°C to low displacement damage of 0.025 and 0.3 dpa under the framework of the US-Japan TITAN program (2007-2013). After cooling down, the HFIR neutron-irradiated tungsten samples were exposed to deuterium plasmas in the Tritium Plasma Experiment, Idaho National Laboratory at 100, 200 and 500 °C twice at the ion fluence of 5×10²⁵ m⁻² to reach a total ion fluence of 1×10²⁶ m⁻² in order to investigate the near surface deuterium retention and saturation via nuclear reaction analysis. Final thermal desorption spectroscopy was performed to elucidate irradiation effect on total deuterium retention. Nuclear reaction analysis results showed that the maximum near surface (<5 µm depth) deuterium concentration increased from 0.5 at % D/W in 0.025 dpa samples to 0.8 at. % D/W in 0.3 dpa samples. The large discrepancy between the total retention via thermal desorption spectroscopy and the near surface retention via nuclear reaction analysis indicated the deuterium was migrated and trapped in bulk (at least 50 µm depth for 0.025 dpa and 35 µm depth for 0.025 dpa) at 500 °C case even in the relatively low ion fluence of 10²⁶ m⁻².

  19. Irradiation effect on deuterium behaviour in low-dose HFIR neutron-irradiated tungsten

    DOE PAGES

    Shimada, Masashi; Cao, G.; Otsuka, T.; ...

    2014-12-01

    Tungsten samples were irradiated by neutrons in the High Flux Isotope Reactor, Oak Ridge National Laboratory at reactor coolant temperatures of 50-70°C to low displacement damage of 0.025 and 0.3 dpa under the framework of the US-Japan TITAN program (2007-2013). After cooling down, the HFIR neutron-irradiated tungsten samples were exposed to deuterium plasmas in the Tritium Plasma Experiment, Idaho National Laboratory at 100, 200 and 500 °C twice at the ion fluence of 5×10²⁵ m⁻² to reach a total ion fluence of 1×10²⁶ m⁻² in order to investigate the near surface deuterium retention and saturation via nuclear reaction analysis. Finalmore » thermal desorption spectroscopy was performed to elucidate irradiation effect on total deuterium retention. Nuclear reaction analysis results showed that the maximum near surface (<5 µm depth) deuterium concentration increased from 0.5 at % D/W in 0.025 dpa samples to 0.8 at. % D/W in 0.3 dpa samples. The large discrepancy between the total retention via thermal desorption spectroscopy and the near surface retention via nuclear reaction analysis indicated the deuterium was migrated and trapped in bulk (at least 50 µm depth for 0.025 dpa and 35 µm depth for 0.025 dpa) at 500 °C case even in the relatively low ion fluence of 10²⁶ m⁻².« less

  20. Numerical simulation of piezoelectric effect of bone under ultrasound irradiation

    NASA Astrophysics Data System (ADS)

    Hosokawa, Atsushi

    2015-07-01

    The piezoelectric effect of bone under ultrasound irradiation was numerically simulated using an elastic finite-difference time-domain method with piezoelectric constitutive equations (PE-FDTD method). First, to demonstrate the validity of the PE-FDTD method, the ultrasound propagation in piezoelectric ceramics was simulated and then compared with the experimental results. The simulated and experimental waveforms propagating through the ceramics were in good agreement. Next, the piezoelectric effect of human cortical bone on the ultrasound propagation was investigated by PE-FDTD simulation. The simulated result showed that the difference between the waveforms propagating through the bone without and with piezoelectricity was negligible. Finally, the spatial distributions of the electric fields in a human femur induced by ultrasound irradiation were simulated. The electric fields were changed by a bone fracture, which depended on piezoelectric anisotropy. In conclusion, the PE-FDTD method is considered to be useful for investigating the piezoelectric effect of bone.

  1. Irradiation damage effects on helium migration in sintered uranium dioxide

    NASA Astrophysics Data System (ADS)

    Martin, G.; Sabathier, C.; Carlot, G.; Desgardin, P.; Raepsaet, C.; Sauvage, T.; Khodja, H.; Garcia, P.

    2012-02-01

    In this study, the effects of radiation on helium migration are investigated through the analysis of polycrystalline uranium dioxide samples irradiated at fluences up to 5 × 10 15 at. cm -2 with 8 MeV iodine ions. Following irradiation, samples are implanted with 500 keV 3He + ions at fluences in the range of 10 16 at. cm -2. Three nuclear reaction analysis (NRA) techniques are subsequently implemented using the 3He( 2H, 1H) 4He reaction. The influence of temperature using NRA was first studied based upon 3He depth profile changes and the on-line monitoring of helium release. The effect of the sample microstructure was also investigated at the grain scale by performing analyses of the helium spatial distribution with a nuclear microprobe. Neither substantial helium release nor depth profile changes are observed at temperatures below 900 °C in irradiated samples. Following annealing at temperatures above 1000 °C, a substantial proportion of the implanted helium is released from the samples. From this temperature upwards, the two dimensional He cartographies reveal that the gas has been preferentially released in the vicinity of grain boundaries. These results can be interpreted in the light of previous studies in terms of gas precipitation and re-solution. Helium precipitation is enhanced in irradiated samples up to 900 °C because of the presence of irradiation induced defects. At temperatures in excess of 1000 °C, the precipitated helium is partly returned to the matrix hence it is preferentially released in regions adjacent to grain boundaries, which appear to act as defect sinks.

  2. Low Level Infrared Irradiance Ocular Effects.

    DTIC Science & Technology

    1978-11-01

    with a fundus camera reticle before each exposure session and between animals exposed on the same day. The beam was visualized on an IR phosphor excited...means of a fundus camera . The exposure and examination apparatus is shown in Figure 2. If a lesion was detected, the power level was decreased, the beam...Documentation of retinal and lenti- cular effects was provided by fundus and slit lamp photography. Opacities were observed on the posterior poles of the rabbit

  3. Effect of different laser irradiation on the dysentery bacilli

    NASA Astrophysics Data System (ADS)

    Ou, Lin; Chen, Rong; Chen, Yanjiao; Li, Depin; Wen, Caixia

    1998-08-01

    The S. flexnesi, which have high drug-resistance especially in Cm, Sm, Tc, SD, were irradiated by Ar+ laser at 488 nm and semiconductor laser at 808 nm. The experiment results have shown that both Ar+ laser and semiconductor laser with power density of 1.7 w/cm2 and irradiation dose of 2000 J/cm2 can conduce to the bacterial lethality and increase the mutation rates of the bacterial drug-sensitivity, and 'Colony Count' method have the superiority over the 'Inhibacteria Ring' method. At the mean time it further indicate that the high power semiconductor laser would play an important role in the sciences of laser biological medicine. But the effect of the near infrared semiconductor laser is far lower than that of Ar+ laser of shorter wavelength at the same irradiation dose. It is clear that the output and irradiation dose of near infrared semiconductor laser shall be increased in order to get the same rates of the bacterial lethality and the drug-sensitivity mutation as Ar+ laser's.

  4. Sterile, injectable cyclodextrin nanoparticles: effects of gamma irradiation and autoclaving.

    PubMed

    Memisoglu-Bilensoy, Erem; Hincal, A Atilla

    2006-03-27

    Sterility is required as stated by compendial requirements and registration authorities worldwide for an injectable drug carrier system. In this study, injectable nanospheres and nanocapsules prepared from amphiphilic beta-cyclodextrin, beta-CDC6, were assessed for their in vitro properties such as particle size distribution, zeta potential, nanoparticle yield (%), drug entrapment efficiency and in vitro drug release profiles. Different sterilization techniques such as gamma irradiation and autoclaving were evaluated for their feasibility regarding the maintenance of the above mentioned nanoparticle properties after sterilization. It was found that amount these techniques, sterilization with gamma irradiation seemed to be the most appropriate technique with no effect on particle size, drug loading and drug release properties. Gamma irradiation causes some chemical changes on beta-CDC6 observed as changes in zeta potential but this does not lead to any significant changes for nanoparticle properties. Autoclaving caused massive aggregation for the nanoparticles followed by precipitation, which led to the conclusion that excessive heat disrupted nanoparticle integrity. Sterile filtration was not feasible since nanoparticle sizes were larger than the filter pore size and the yield after sterilization was very low. Thus, it can be concluded that blank and drug loaded beta-CDC6 nanospheres and nanocapsules are capable of being sterilized by gamma irradiation.

  5. Electron microscopy of irradiation effects in space

    NASA Technical Reports Server (NTRS)

    Maurette, M.; Price, P. B.

    1975-01-01

    The paper discusses several discoveries made in the study of lunar material. In the examination of the effects of solar wind implantations the topics covered include (1) solar wind radiation damage parameters and their aging characteristics, (2) the theory of the ancient solar wind, (3) the solar wind sputtering erosion rate, (4) the physicochemical properties of amorphous coatings, (5) maturity indexes and the macroscopic properties of the lunar regolith, (6) solar wind gas bubbles, (7) the composition of very heavy nuclei in the contemporary solar wind, and (8) track aging processes. Conclusions are drawn from the results about other extraterrestrial features such as the parent bodies of the meteorites, early solar nebulas, and interstellar clouds.

  6. Clinical and immunologic effects of fractionated total lymphoid irradiation in refractory rheumatoid arthritis

    SciTech Connect

    Trentham, D.E.; Belli, J.A.Anderson, R.J.; Buckley, J.A.; Goetzl, E.J.; David, J.R.; Austen, K.F.

    1981-10-01

    Ten patients with refractory rheumatoid arthritis were given 3000 rad of fractionated total lymphoid irradiation in an uncontrolled therapeutic trial. Total lymphoid irradiation was associated with objective evidence of considerable clinical improvement in eight patients and with reduced blood lymphocyte counts in all 10. On completion of irradiation, there was an abrogation of lymphocyte reactivity in vitro in the patients with clinical responses, but abnormal antibody activities characteristic of rheumatoid arthritis and normal components of humoral immunity were not suppressed. Partial recrudescence of arthritis occurred shortly before a year after the completion of irradiation and was paralleled by a restitution of lymphocyte concentrations and responsiveness to mitogens to levels similar to those observed before irradiation. These data provide further evidence of T-cell involvement in the pathogenesis of rheumatoid arthritis and demonstrate that total lymphoid irradiation can induce temporary relief, but they do not ascertain whether the natural history of this disease was altered.

  7. Clinical and immunologic effects of fractionated total lymphoid irradiation in refractory rheumatoid arthritis

    SciTech Connect

    Trentham, D.E.; Belli, J.A.; Anderson, R.J.; Buckley, J.A.; Goetzl, E.J.; David, J.R.; Austen, K.F.

    1981-10-22

    Ten patients with refractory rheumatoid arthritis were given 3000 rad of fractionated total lymphoid irradiation in an uncontrolled therapeutic trial. Total lymphoid irradiation was associated with objective evidence of considerable clinical improvement in eight patients and with reduced blood lymphocyte counts in all 10. On completion of irradiation, there was an abrogation of lymphocyte reactivity in vitro in the patients with clinical responses, but abnormal antibody activities characteristic of rheumatoid arthritis and normal components of humoral immunity were not suppressed. Partial recrudescence of arthritis occurred shortly after a year after the completion of irradiation and was paralleled by a restitution of lymphocyte concentrations and responsiveness to mitogens to levels similar to those observed before irradiation. These data provide further evidence of T-cell involvement in the pathogenesis of rheumatoid arthritis and demonstrate that total lymphoid irradiation can induce temporary relief, but they do not ascertain whether the natural history of this disease was altered.

  8. The effects of tungsten's pre-irradiation surface condition on helium-irradiated morphology

    DOE PAGES

    Garrison, Lauren M.; Kulcinski, Gerald L.

    2015-07-17

    Erosion is a concern associated with the use of tungsten as a plasma-facing component in fusion reactors. To compare the damage progression, polycrystalline tungsten (PCW) and (110) single crystal tungsten (SCW) samples were prepared with (1) a mechanical polish (MP) with roughness values in the range of 0.018–0.020 μm and (2) an MP and electropolish (MPEP) resulting in roughness values of 0.010–0.020 μm for PCW and 0.003–0.005 μm for SCW samples. Samples were irradiated with 30 keV He+ at 1173 K to fluences between 3 × 1021 and 6 × 1022 He/m2. The morphologies that developed after low-fluence bombardment weremore » different for each type of sample—MP SCW, MPEP SCW, MP PCW, and MPEP PCW. At the highest fluence, the SCW MPEP sample lost significantly more mass and developed a different morphology than the MP SCW sample. The PCW samples developed a similar morphology and had similar mass loss at the highest fluence. Surface preparation can have a significant effect on post-irradiation morphology that should be considered for the design of future fusion reactors such as ITER and DEMO.« less

  9. The effects of tungsten's pre-irradiation surface condition on helium-irradiated morphology

    SciTech Connect

    Garrison, Lauren M.; Kulcinski, Gerald L.

    2015-07-17

    Erosion is a concern associated with the use of tungsten as a plasma-facing component in fusion reactors. To compare the damage progression, polycrystalline tungsten (PCW) and (110) single crystal tungsten (SCW) samples were prepared with (1) a mechanical polish (MP) with roughness values in the range of 0.018–0.020 μm and (2) an MP and electropolish (MPEP) resulting in roughness values of 0.010–0.020 μm for PCW and 0.003–0.005 μm for SCW samples. Samples were irradiated with 30 keV He+ at 1173 K to fluences between 3 × 1021 and 6 × 1022 He/m2. The morphologies that developed after low-fluence bombardment were different for each type of sample—MP SCW, MPEP SCW, MP PCW, and MPEP PCW. At the highest fluence, the SCW MPEP sample lost significantly more mass and developed a different morphology than the MP SCW sample. The PCW samples developed a similar morphology and had similar mass loss at the highest fluence. Surface preparation can have a significant effect on post-irradiation morphology that should be considered for the design of future fusion reactors such as ITER and DEMO.

  10. Investigation of irradiation effect on npn BJT electrical properties

    NASA Astrophysics Data System (ADS)

    Assaf, J.

    2016-10-01

    The irradiation effects of neutrons and gamma rays on a commercial type of npn Bipolar Junction Transistors (BJTs) are reported. The decrease of the current gain factor hFE for increasing dose was analyzed. Reduction ratio for hFE between 84% and 98% at the saturated reduction level have been obtained. This is due to a small decreasing in the collector current IC and a large increasing in the base current IB, where hFE=IC/IB. Reduction ratio per dose indicates the higher influence of the neutrons than that of gamma for the same equivalent dose. Moreover, the voltage gain as a function of the frequency decremented after irradiation, and the collector saturated voltage (VCEsat) was increased. These effects illustrate the damage in the function of BJTs.

  11. Effective ultraviolet irradiance measurements from artificial tanning devices in Greece.

    PubMed

    Petri, Aspasia; Karabetsos, Efthymios

    2015-12-01

    Artificial tanning remains very popular worldwide, despite the International Agency for Research on Cancer classification of ultraviolet (UV) radiation from sunbeds as 'carcinogenic to humans'. Greek Atomic Energy Commission has initiated a surveillance action of the artificial tanning devices in Greece in order to record the effective irradiance levels from the sunbeds and to inform and synchronise the domestic artificial tanning business sector with the requirements of the European Standard EN 60335-2-27:2010. In this direction, in situ measurements of UV emissions from sunbeds in solaria businesses all over Greece were performed from October 2013 until July 2014, with a radiometer and a portable single-monochromator spectrophotometer. Analysis of the measurements' results revealed that effective irradiance in ∼60 % of the measured sunbeds exceeded the 0.3 W m(-2) limit value set by EN 60335-2-27:2010 and only 20 % of the devices could be categorised as UV type 3.

  12. Effect of irradiated pork on physicochemical properties of meat emulsions

    NASA Astrophysics Data System (ADS)

    Choi, Yun-Sang; Sung, Jung-Min; Jeong, Tae-Jun; Hwang, Ko-Eun; Song, Dong-Heon; Ham, Youn-Kyung; Kim, Hyun-Wook; Kim, Young-Boong; Kim, Cheon-Jei

    2016-02-01

    The effect of pork irradiated with doses up to 10 kGy on meat emulsions formulated with carboxy methyl cellulose (CMC) was investigated. Raw pork was vacuums packaged at a thickness of 2.0 cm and irradiated by X-ray linear accelerator (15 kW, 5 MeV). The emulsion had higher lightness, myofibrillar protein solubility, total protein solubility, and apparent viscosity with increasing doses, whereas cooking loss, total expressible fluid separation, and hardness decreased. There were no significant differences in fat separation, sarcoplasmic protein solubility, springiness, and cohesiveness. Our results indicated that it is treatment by ionizing radiation which causes the effects the physicochemical properties of the final raw meat product.

  13. A comparative study on the effects of electron beam irradiation on imidacloprid-resistant and -susceptible Aphis gossypii (Hemiptera: Aphididae)

    NASA Astrophysics Data System (ADS)

    Yun, Seung-Hwan; Koo, Hyun-Na; Lee, Seon-Woo; Kim, Hyun Kyung; Kim, Yuri; Han, Bumsoo; Kim, Gil-Hah

    2015-07-01

    The melon and cotton aphid, Aphis gossypii, is a polyphagous insect pest. This study compared the development, reproduction, DNA damage, recovery, and gene expression in imidacloprid-resistant (IMI-R) and -susceptible (S) strains of A. gossypii by electron beam irradiation. When 1st instar nymphs were irradiated with 100 Gy, the fecundity (nymphs of F1 generation) of the resultant adults were completely inhibited. When adults were irradiated with 200 Gy, the number of total 1st instar nymphs produced per adult was 3.0±1.7 and 1.9±1.4 in the S and IMI-R strains, respectively, but adult development was completely suppressed. However, electron beam irradiation did not affect adult longevity in either the S or IMI-R strain. There was no statistically significant difference between the effect of irradiation on the S and IMI-R strains. Therefore, electron beam irradiation at 200 Gy could be used as a phytosanitary irradiation treatment for both S and IMI-R strains of A. gossypii. The DNA damage caused by electron beam irradiation was evaluated by an alkaline comet assay. Exposure to an electron beam (50 Gy) induced DNA damage that was repaired to a similar level as the untreated control group (0 Gy) over time. However, at more than 100 Gy, the DNA damage was not completely repaired. The expression of P450, HSP70, cuticle protein, and elongation factor genes were higher in the IMI-R strain than in the S strain.

  14. Effects of combined neutron and gamma irradiation upon silicone foam

    NASA Astrophysics Data System (ADS)

    Liu, Bo; Wang, Pu-Cheng; Ao, Yin-Yong; Zhao, Yan; An, You; Chen, Hong-Bing; Huang, Wei

    2017-04-01

    The total dose effect of combined fast-neutron beam and 60Co γ-ray radiation on silicone foam in air and nitrogen were investigated, respectively. The results show that foam hardening occurs and crystallization of polymer matrix decreases with increasing dose. Gas chromatograph was used to identify the kinetics of volatile products generating, which generally increase with increasing total dose. The study indicates that combined neutron and gamma irradiation would influence silicone foam property obviously during the investigated dose range.

  15. Betulin Derivatives Effectively Suppress Inflammation in Vitro and in Vivo.

    PubMed

    Laavola, Mirka; Haavikko, Raisa; Hämäläinen, Mari; Leppänen, Tiina; Nieminen, Riina; Alakurtti, Sami; Moreira, Vânia M; Yli-Kauhaluoma, Jari; Moilanen, Eeva

    2016-02-26

    Betulin is a pharmacologically active triterpenoid found in the bark of the birch tree (Betula sp. L.). Betulin and betulinic acid are structurally related to anti-inflammatory steroids, but little is known about their potential anti-inflammatory properties. In the present study, the inflammatory gene expression and the anti-inflammatory properties of betulin, betulinic acid, and 16 semisynthetic betulin derivatives were investigated. Betulin derivatives 3, 4, and 5 selectively inhibited the expression of the inducible nitric oxide synthase (iNOS) in a post-transcriptional manner. They also inhibited nitric oxide (NO) production but had no effect on the other inflammatory factors studied. More interestingly, a new anti-inflammatory betulin derivative 9 with a wide-spectrum anti-inflammatory activity was discovered. Compound 9 was found to suppress the expression of cytokines interleukin-6 (IL-6) and monocyte chemotactic protein-1 (MCP-1), as well as that of prostaglandin synthase-2 (COX-2) in addition to iNOS. The in vivo anti-inflammatory effect of compound 9 was indicated via significant suppression of the carrageenan-induced paw inflammation in mice. The results show, for the first time, that the pyrazole-fused betulin derivative (9) and related compounds have anti-inflammatory properties that could be utilized in drug development.

  16. Bactericidal effect of Nd:YAG laser irradiation in endodontics

    NASA Astrophysics Data System (ADS)

    Aun, Carlos E.; Barberini, Alexandre F.; Camargo, Selma C. C.; Silva Kfouri, Luciana; Lorenzetti Simionato, Maria R.

    1999-05-01

    The success of endodontic therapy is based on the elimination of bacterial colonization from the endodontic system and periapical tissues. Recent studies have been showing the bactericidal effect of laser in root canal treatment. The propose of the study is to evaluate the effect of Nd:YAG laser irradiation in contaminated root canal treatment. The propose of the study is to evaluate the effect of Nd:YAG laser irradiation in contaminated root canals from upper central incisor. For the experiment 12 teeth were selected, respect at the apical third, sterilized, and 10 μm Streptococcus sanguis liquid culture were inoculated in the root canals. The laser test groups were irradiated with Nd:YAG laser at standard setting of 15Hz, 100mj and 1,5 W for 10, 20 and 30 seconds each in slow helicoidal movements from the apex to the top using a 300 micrometers fiber. After the procedure the specimens were placed in Tryptic Soy Agar, the number of colony forming units was evaluated. The experiment showed a significant reduction on viability of Streptococcus sanguis at the respective time of 20 and 30 seconds.

  17. Effects of Ru(CO)3Cl-glycinate on the developmental toxicities induced by X-ray and carbon-ion irradiation in zebrafish embryos.

    PubMed

    Zhou, Rong; Song, Jing'e; Si, Jing; Zhang, Hong; Liu, Bin; Gan, Lu; Zhou, Xin; Wang, Yupei; Yan, Junfang; Zhang, Qianjing

    The inhibitory effects of carbon monoxide (CO), generated by Ru(CO)3Cl-glycinate [CO-releasing molecule (CORM-3)], on developmental toxicity in zebrafish embryos induced by ionizing radiation with different linear energy transfer (LET) were studied. Zebrafish embryos at 5h post-fertilization were irradiated with X-ray (low-LET) and carbon-ion (high-LET) with or without pretreatment of CORM-3 1h before irradiation. CORM-3 pre-treatment showed a significant inhibitory effect on X-ray irradiation-induced developmental toxicity, but had little effect on carbon-ion irradiation-induced developmental toxicity. X-ray irradiation-induced significant increase in ROS levels and cell apoptosis could be modified by CORM-3 pretreatment. However, embryos exposed to carbon-ion irradiation showed significantly increase of cell apoptosis without obvious ROS generation, which could not be attenuated by CORM-3 pretreatment. CORM-3 could inhibit apoptosis induced by ionizing radiation with low-LET as an effective ROS scavenger. The expression of pro-apoptotic genes increased significantly after X-ray irradiation, but increased expression was reduced markedly when CORM-3 was applied before irradiation. Moreover, the protein levels of P53 and γ-H2AX increased markedly after X-ray irradiation, which could be modified by the presence of CORM-3. The protective effect of CORM-3 on X-ray irradiation occurred mainly by suppressing ROS generation and DNA damage, and thus inhibiting the activation of P53 and the mitochondrial apoptotic pathway, leading to the attenuation of cell apoptosis and consequently alleviating X-ray irradiation-induced developmental toxicity at lethal and sub-lethal levels.

  18. Effects of CO/sub 2/ laser irradiation on gingiva

    SciTech Connect

    Rossmann, J.A.; Gottlieb, S.; Koudelka, B.M.; McQuade, M.J.

    1987-06-01

    A CO/sub 2/ laser (Coherent Medical Model 400) was used to irradiate the gingival tissue of a cynomolgous monkey to determine laser effects on the epithelium and underlying connective tissue. A focal length of 400 mm and a 10-watt power setting at 0.2- and 0.5-second exposure was used. Biopsy results indicated that a 0.2-second duration of CO/sub 2/ laser irradiation was inadequate to completely de-epithelialize the gingival tissue. A 0.5-second exposure exhibited complete epithelial destruction with little or no disturbance of the underlying connective tissue layer and viable connective tissue 1.0 mm below the impact site.

  19. Effects of self-irradiation in plutonium alloys

    SciTech Connect

    Chung, B. W.; Lema, K. E.; Allen, P. G.

    2015-09-16

    In this paper, we present updated results of self-irradiation effects on 238Pu-enriched 239Pu alloys measured by immersion density, dilatometry, and tensile tests. We obtained the self-irradiation equivalent time of nearly 200 years, nearly 100 years longer than in our previous papers. At this extended aging, we find the rate of decrease in density has slowed significantly, stabilizing around 15.73 g/cc, without signs of void swelling. The volume expansion measured at 35°C also shows apparent saturation at less than 0.25%. Quasi-static tensile measurement still show gradual increase in the strength of plutonium alloys with age.

  20. Irradiation Effects on RIA Fragmentation CU Beam Dump

    SciTech Connect

    Reyes, S; Boles, J L; Ahle, L E; Stein, W; Wirth, B D

    2005-05-20

    Within the scope of conceptual research and development (R&D) activities in support of the Rare Isotope Accelerator (RIA) facility, high priority is given to the development of high-power fragmentation beam dumps. A pre-study was made of a static water-cooled Cu beam dump that can meet requirements for a 400 MeV/u uranium beam. The issue of beam sputtering was addressed and found to be insignificant. Preliminary radiation transport simulations show significant damage (in displacements per atom, DPA) in the vicinity of the Bragg peak of the uranium ions. Experimental data show that defects in Cu following neutron or high-energy particle irradiation tend to saturate at doses between 1 and 5 DPA, and this saturation in defect density also results in saturation of mechanical property degradation. However, effects of swift heavy ion irradiation and the production of gaseous and solid transmutant elements still need to be addressed. Initial calculations indicate that He concentrations on the order of 400 appm are produced in the beam dump after several weeks of continuous operation and He embrittlement may be a concern. Recommendations are made for further investigation of Cu irradiation effects for RIA-relevant conditions.

  1. Irradiation Effects on RIA Fragmentation CU Beam Dump

    SciTech Connect

    Reyes, S; Boles, J L; Ahle, L E; Stein, W; Wirth, B D

    2005-05-09

    Within the scope of conceptual research and development (R&D) activities in support of the Rare Isotope Accelerator (RIA) facility, high priority is given to the development of high-power fragmentation beam dumps. A pre-study was made of a static water-cooled Cu beam dump that can meet requirements for a 400 MeV/u uranium beam. The issue of beam sputtering was addressed and found to be insignificant. Preliminary radiation transport simulations show significant damage (in displacements per atom, DPA) in the vicinity of the Bragg peak of the uranium ions. Experimental data show that defects in Cu following neutron or high-energy particle irradiation tend to saturate at doses between 1 and 5 DPA, and this saturation in defect density also results in saturation of mechanical property degradation. However, effects of swift heavy ion irradiation and the production of gaseous and solid transmutant elements still need to be addressed. Initial calculations indicate that He concentrations on the order of 400 appm are produced in the beam dump after several weeks of continuous operation and He embrittlement may be a concern. Recommendations are made for further investigation of Cu irradiation effects for RIA-relevant conditions.

  2. Chemical repair activity of free radical scavenger edaravone: reduction reactions with dGMP hydroxyl radical adducts and suppression of base lesions and AP sites on irradiated plasmid DNA.

    PubMed

    Hata, Kuniki; Urushibara, Ayumi; Yamashita, Shinichi; Lin, Mingzhang; Muroya, Yusa; Shikazono, Naoya; Yokoya, Akinari; Fu, Haiying; Katsumura, Yosuke

    2015-01-01

    Reactions of edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one) with deoxyguanosine monophosphate (dGMP) hydroxyl radical adducts were investigated by pulse radiolysis technique. Edaravone was found to reduce the dGMP hydroxyl radical adducts through electron transfer reactions. The rate constants of the reactions were greater than 4 × 10(8) dm(3) mol(-1) s(-1) and similar to those of the reactions of ascorbic acid, which is a representative antioxidant. Yields of single-strand breaks, base lesions, and abasic sites produced in pUC18 plasmid DNA by gamma ray irradiation in the presence of low concentrations (10-1000 μmol dm(-3)) of edaravone were also quantified, and the chemical repair activity of edaravone was estimated by a method recently developed by the authors. By comparing suppression efficiencies to the induction of each DNA lesion, it was found that base lesions and abasic sites were suppressed by the chemical repair activity of edaravone, although the suppression of single-strand breaks was not very effective. This phenomenon was attributed to the chemical repair activity of edaravone toward base lesions and abasic sites. However, the chemical repair activity of edaravone for base lesions was lower than that of ascorbic acid.

  3. Effect of dose rate on inactivation of microorganisms in spices by electron-beams and gamma-rays irradiation

    NASA Astrophysics Data System (ADS)

    Ito, Hitoshi; Islam, Md. Shamsul

    1994-06-01

    Total aerobic bacteria in spices used in this study were determined to be 1 × 10 6 to 6 × 10 7 per gram. A study on the inactivation of microorganisms in spices showed that doses of 6-9kGy of EB (electron-beams) or γ-irradiation were required to reduce the total aerobic bacteria in many However, a little increase of resistance was observed on the inactivation of total aerobic bacteria in many spices in case of EB irradiation. These difference of radiation sensitivities between EB and γ-rays was explained by dose rate effect on oxidation damage to microorganisms from the results of radiation sensitivities of Bacillus pumilus and B. megaterium spores at dry conditions. On the other hand, these high dose rate of EB irradiation suppressed the increase of peroxide values in spices at high dose irradiation up to 80 kGy. However, components of essential oils in spices were not changed even irradiated up to 50 kGy with EB and γ-rays.

  4. Effect of gamma irradiation on quality of kiwifruit ( Actinidia deliciosa var. deliciosa cv. Hayward)

    NASA Astrophysics Data System (ADS)

    kim, Kyoung-Hee; Yook, Hong-Sun

    2009-06-01

    Ionizing radiation is able to inactivate the three pathogens of Botrytis cinerea, Diaporthe actinidiae, and Botryosphaeria dothidea in kiwifruit. Irradiated kiwifruits appeared softer compared to non-irradiated kiwifruits. The color and organic acid content of kiwifruits were minimally affected by the irradiation. Irradiated fruits showed a decrease in the total soluble solids content with increasing irradiation dose. Irradiation of kiwifruit up to 3 kGy had negative effects on vitamin C content and antioxidant activity, but it contributed to improving sensory quality.

  5. Effects of Ga ion-beam irradiation on monolayer graphene

    SciTech Connect

    Wang, Quan; Mao, Wei; Zhang, Yanmin; Shao, Ying; Ren, Naifei; Ge, Daohan

    2013-08-12

    The effects of Ga ion on the single layer graphene (SLG) have been studied by Raman spectroscopy (RS), SEM, and field-effect characterization. Under vacuum conditions, Ga ion-irradiation can induce disorders and cause red shift of 2D band of RS, rather than lattice damage in high quality SLG. The compressive strain induced by Ga ion decreases the crystalline size in SLG, which is responsible for the variation of Raman scattering and electrical properties. Nonlinear out-put characteristic and resistance increased are also found in the I-V measurement. The results have important implications during CVD graphene characterization and related device fabrication.

  6. Impurities effect on the swelling of neutron irradiated beryllium

    SciTech Connect

    Donne, M.D.; Scaffidi-Argentina, F.

    1995-09-01

    An important factor controlling the swelling behaviour of fast neutron irradiated beryllium is the impurity content which can strongly affect both the surface tension and the creep strength of this material. Being the volume swelling of the old beryllium (early sixties) systematically higher than that of the more modem one (end of the seventies), a sensitivity analysis with the aid of the computer code ANFIBE (ANalysis of Fusion Irradiated BEryllium) to investigate the effect of these material properties on the swelling behaviour of neutron irradiated beryllium has been performed. Two sets of experimental data have been selected: the first one named Western refers to quite recently produced Western beryllium, whilst the second one, named Russian refers to relatively old (early sixties) Russian beryllium containing a higher impurity rate than the Western one. The results obtained with the ANFIBE Code were assessed by comparison with experimental data and the used material properties were compared with the data available in the literature. Good agreement between calculated and measured values has been found.

  7. Irradiation effects in close binaries in an electron scattering medium

    NASA Astrophysics Data System (ADS)

    Varghese, B. A.; Srinivasa Rao, M.

    2016-03-01

    In a close binary system, the effects of irradiation are studied from an extended surface of the secondary component on the atmosphere of the primary. Primary and the secondary components are assumed to have equal radii and the thickness of the atmosphere is assumed to be twice that of the stellar radius of the primary component. Self radiation of the primary component (Ss) is calculated through a numerical solution of line transfer equation in the comoving frame with Compton broadening due to electron scattering. The solution is developed through discrete space theory to deal with different velocities in a spherically expanding medium. The irradiation from the secondary (SI) is calculated using one dimensional rod model. It is assumed to be one, five and ten times the self radiation. The total source function (S=Ss+SI) is the sum of the source functions due to self radiation and that due to irradiation. The line fluxes are computed along the line of sight by using the above source functions. Line profiles are also computed for different line center optical depths along the line of sight of the observer at infinity.

  8. Effects of neutron irradiation on polycrystalline Mg11B2

    NASA Astrophysics Data System (ADS)

    Tarantini, C.; Aebersold, H. U.; Braccini, V.; Celentano, G.; Ferdeghini, C.; Ferrando, V.; Gambardella, U.; Gatti, F.; Lehmann, E.; Manfrinetti, P.; Marré, D.; Palenzona, A.; Pallecchi, I.; Sheikin, I.; Siri, A. S.; Putti, M.

    2006-04-01

    We studied the influence of the disorder introduced in polycrystalline MgB2 samples by neutron irradiation. To circumvent self-shielding effects due to the strong interaction between thermal neutrons and B10 we employed isotopically enriched B11 which contains 40 times less B10 than natural B. The comparison of electrical and structural properties of different series of samples irradiated in different neutron sources, also using Cd shields, allowed us to conclude that, despite the low B10 content, the main damage mechanisms are caused by thermal neutrons, whereas fast neutrons play a minor role. Irradiation leads to an improvement in both upper critical field and critical current density for an exposure level in the range 1-2×1018cm-2 . With increasing fluence the superconducting properties are depressed. An in-depth analysis of the critical field and current density behavior has been carried out to identify what scattering and pinning mechanisms come into play. Finally, the correlation between some characteristic lengths and the transition widths is analyzed.

  9. Effect of gamma irradiation on antinutritional factors in broad bean

    NASA Astrophysics Data System (ADS)

    Al-Kaisey, Mahdi T.; Alwan, Abdul-Kader H.; Mohammad, Manal H.; Saeed, Amjed H.

    2003-06-01

    The effect of gamma irradiation on the level of antinutritional factors (trypsin inhibitor (TI), phytic acid and oligosaccharides) of broad bean was investigated. The seeds were subjected to gamma irradiation at 0, 2.5, 5, 7.5 and 10 kGy, respectively using cobalt-60 gamma radiation with a dose rate 2.37 kGy/h. TI activity was reduced by 4.5%, 6.7%, 8.5% and 9.2% at 2.5, 5, 7.5 and 10 kGy, respectively. Meanwhile, irradiation at 10.2, 12.3, 15.4 and 18.2 kGy reduced the phytic acid content. The flatulence causing oligosaccharides were decreased as the radiation dose increased. The chemical composition (protein, oil, ash and total carbohydrates) of the tested seeds was determined. Gamma radiation seems to be a good procedure to improve the quality of broad bean from the nutritional point of view.

  10. Gamma-ray irradiation effect on corrosion rates of stainless steel, Ti and Ti-5Ta in boiling 9N nitric acid

    NASA Astrophysics Data System (ADS)

    Yamamoto, Takao; Tsukui, Shigeki; Okamoto, Shinichi; Nagai, Takayuki; Takeuchi, Masayuki; Takeda, Seiichiro; Tanaka, Yasumasa

    1996-03-01

    Irradiation effect of γ-rays on corrosion rates of stainless steel (type 304L), titanium and a titanium-tantalum alloy (Ti-5Ta) in 9N boiling nitric acid was investigated by measuring weight losses of specimens leached under a 60Co γ-ray environment of 1 kCkg -1/h (4 MR/h). Tests without irradiation were as well performed to obtain reference data. Plots of the weight loss normalized to specimen's surface area against total leaching time exhibited linear relations when the first leaching batch is neglected. The corrosion rates calculated from the gradients indicated slight, though significant, irradiation effects, an enhancement in stainless steel while suppressions in Ti and Ti-5Ta. Corrosion modes were found to be insensitive to the irradiation.

  11. Commercial sunscreen formulations: UVB irradiation stability and effect on UVB irradiation-induced skin oxidative stress and inflammation.

    PubMed

    Vilela, Fernanda M P; Oliveira, Franciane M; Vicentini, Fabiana T M C; Casagrande, Rubia; Verri, Waldiceu A; Cunha, Thiago M; Fonseca, Maria J V

    2016-10-01

    Evidence shows that sunscreens undergo degradation processes induced by UV irradiation forming free radicals, which reduces skin protection. In this regard, the biological effects of three commercial sunscreen formulations upon UVB irradiation in the skin were investigated. The three formulations had in common the presence of benzophenone-3 added with octyl methoxycinnamate or octyl salycilate or both, which are regular UV filters in sunscreens. The results show that formulations F1 and F2 presented partial degradation upon UVB irradiation. Formulations F1 and F2 presented higher skin penetration profiles than F3. None of the formulations avoided UVB irradiation-induced GSH depletion, but inhibited reduction of SOD activity, suggesting the tested formulations did not present as a major mechanism inhibiting all UVB irradiation-triggered oxidative stress pathways. The formulations avoided the increase of myeloperoxidase activity and cytokine production (IL-1β and TNF-α), but with different levels of protection in relation to the IL-1β release. Concluding, UVB irradiation can reduce the stability of sunscreens, which in turn, present the undesirable properties of reaching viable skin. Additionally, the same SPF does not mean that different sunscreens will present the same biological effects as SPF is solely based on a skin erythema response. This found opens up perspectives to consider additional studies to reach highly safe sunscreens.

  12. Evaluation of hail suppression programme effectiveness using radar derived parameters

    NASA Astrophysics Data System (ADS)

    Tani, Satyanarayana; Paulitsch, Helmut; Teschl, Reinhard; Süsser-Rechberger, Barbara

    2016-04-01

    The objective of this study is evaluating "the operational hail suppression programme" in the province of Styria, Austria "for the year 2015". For the evaluation purpose the HAILSYS software tool was developed by integrating single polarization C-band weather radar data, aircraft trajectory, radiosonde freezing level data, hail events and crop damages information from the ground. The hail related radar derived parameters are: hail mass aloft, hail mass flux, probability of hail, vertical integrated hail mass, hail kinetic energy flux, and storm severity index. The spatial maps of hail kinetic energy and hail mass were developed to evaluate the seeding effect. The time history plots of vertical integrated hail mass, hail mass aloft and the probability of hail are drawn over an entire cell lifetime. The sensitivity and variation of radar hail parameters over time and associated changes due to cloud seeding will be presented.

  13. Suppressing exchange effects in diffusion-ordered NMR spectroscopy.

    PubMed

    Aguilar, Juan A; Adams, Ralph W; Nilsson, Mathias; Morris, Gareth A

    2014-01-01

    In diffusion-ordered spectroscopy (DOSY) the aim is to separate signals from different molecular species according to their different diffusion coefficients. Each species has its individual diffusion coefficient (that may accidentally coincide with that of another species, e.g. if they are of very similar size). In exchanging systems, however, there is a serious complication in that the apparent diffusion coefficient of an exchanging signal will be a compromise that depends, among other factors, on the diffusion coefficients of the exchange partners and the rate of exchange between them. The DOSY spectrum will be much harder to interpret and can often give the appearance of extra (spurious) components in the mixture. Here a new and surprisingly simple experiment is described that suppresses the effects of exchange on apparent diffusion coefficients, restoring the simplicity of interpretation enjoyed by non-exchanging systems.

  14. TiO2 nanoparticles suppress Escherichia coli cell division in the absence of UV irradiation in acidic conditions.

    PubMed

    Zhukova, Lyudmila V; Kiwi, John; Nikandrov, Vitaly V

    2012-09-01

    TiO(2) nanoparticles (NPs) activated by UV irradiation are known to have a bactericidal effect. In this study we report the details of TiO(2) NPs influence on the colony-forming capacity of E. coli in the dark at pH 4.0-4.5. At this pH the bacterial cells are negatively charged and TiO(2) NPs present a positive charge. A 60 min contact between E. coli with TiO(2) at concentrations of 0.02-0.2 mg/mL led to a reduction of E. coli cell number from 10(8) to 10(4)CFU/mL. After the reduction the system remains unchanged during the subsequent incubation. The observed reduction was a function on the initial E. coli concentration. In the presence of 0.04 mg/mL TiO(2) the colony-forming units (CFU) reduction after 60 min was of four-five orders of magnitude when the initial concentration was 10(8) cells/mL. But when starting with an E. coli concentration of 10(7) cells/mL the cell number reduction was less than one order of magnitude. Less than one order of magnitude cell number reduction was also observed for suspensions of E. coli 10(8) cells/mL and 0.002 mg/mL of TiO(2). The bacteria number reduction was always accompanied by the formation of cell aggregates. During cell incubation with TiO(2), the pH of the suspension increased, but did not reach the TiO(2) isoelectric point (IEP). E. coli cells stained with the fluorescent dye acridine orange (AO) showed that the fluorescence of single cells remained unchanged after incubation in the presence of TiO(2). The color change of fluorescence was revealed only in aggregated cells. This suggests changes in the physiologic state of E. coli incorporated into the aggregates. Aggregates of E. coli occur due to the electrostatic interaction between TiO(2) NPs and the bacterial cell surface. A hypothesis is suggested in this study to explain the CFU reduction and the retention of a certain irreducible number of cells capable of further division in the suspension in the presence of TiO(2) in the dark.

  15. Neutron irradiation effects in Fe and Fe-Cr at 300 °C

    SciTech Connect

    Chen, Wei-Ying; Miao, Yinbin; Gan, Jian; Okuniewski, Maria A.; Maloy, Stuart A.; Stubbins, James F.

    2016-06-01

    Fe and Fe-Cr (Cr = 10–16 at.%) specimens were neutron-irradiated at 300 °C to 0.01, 0.1 and 1 dpa. The TEM observations indicated that the Cr significantly reduced the mobility of dislocation loops and suppressed vacancy clustering, leading to distinct damage microstructures between Fe and Fe-Cr. Irradiation-induced dislocation loops in Fe were heterogeneously observed in the vicinity of grown-in dislocations, whereas the loop distribution observed in Fe-Cr is much more uniform. Voids were observed in the irradiated Fe samples, but not in irradiated Fe-Cr samples. Increasing Cr content in Fe-Cr results in a higher density, and a smaller size of irradiation-induced dislocation loops. Orowan mechanism was used to correlate the observed microstructure and hardening, which showed that the hardening in Fe-Cr can be attributed to the formation of dislocation loops and α' precipitates.

  16. Non-grey thermal effects in irradiated planets atmospheres

    NASA Astrophysics Data System (ADS)

    Parmentier, Vivien; Guillot, Tristan; Fortney, Jonathan J.; Marley, Mark S.

    2016-01-01

    The large diversity of exoplanets in terms of irradiation temperature, gravity and chemical composition discovered around stars with different properties call for the development of fast, accurate and versatile atmospheric models. We derive a new, non-grey analytical model for the thermal structure of irradiated exoplanets. Using two different opacity bands in the thermal frequency range, we highlight the dual role of thermal non-grey opacities in shaping the temperature profile of the atmosphere. Opacities dominated by lines enable the upper atmosphere to cool down significantly compared to a grey atmosphere whereas opacities dominated by bands lead both to a significant cooling of the upper atmosphere and a significant heating of the deep atmosphere.We compare our analytical model to a grid of temperature-pressure profiles for solar composition atmospheres obtained with a state-of-the-art numerical model taking into account the full wavelength, temperature and pressure dependence of the opacities. We demonstrate the importance of thermal non-grey opacities in setting the deep temperature of irradiated giant planets atmospheres. In the particular case of highly irradiated planets we show that the presence of TiO in their atmospheres alters both the optical and the thermal opacities. The greenhouse effect - a semi-grey effect - and the "blanketing effect" - an intrisically non-grey effect - contribute equally to set the deep temperature profile of the planet atmosphere. We conclude that non-grey thermal effects are fundamental to understand the deep temperature profile of hot Jupiters.Our calibrated analytical model matches the numerical model within 10% over a wide range of effective temperature, internal temperature and gravities and properly predict the depth of the radiative/convective boundary, an important quantity to understand the cooling history of a giant planet. Such a fast and accurate model can be of great use when numerous temperature profiles need to

  17. Enhancing plant productivity while suppressing biofilm growth in a windowfarm system using beneficial bacteria and ultraviolet irradiation.

    PubMed

    Lee, Seungjun; Ge, Chongtao; Bohrerova, Zuzana; Grewal, Parwinder S; Lee, Jiyoung

    2015-07-01

    Common problems in a windowfarm system (a vertical and indoor hydroponic system) are phytopathogen infections in plants and excessive buildup of biofilms. The objectives of this study were (i) to promote plant health by making plants more resistant to infection by using beneficial biosurfactant-producing Pseudomonas chlororaphis around the roots and (ii) to minimize biofilm buildup by ultraviolet (UV) irradiation of the water reservoir, thereby extending the lifespan of the whole system with minimal maintenance. Pseudomonas chlororaphis-treated lettuce grew significantly better than nontreated lettuce, as indicated by enhancement of color, mass, length, and number of leaves per head (p < 0.05). The death rate of the lettuce was reduced by ∼ 50% when the lettuce was treated with P. chlororaphis. UV irradiation reduced the bacteria (4 log reduction) and algae (4 log reduction) in the water reservoirs and water tubing systems. Introduction of P. chlororaphis into the system promoted plant growth and reduced damage caused by the plant pathogen Pythium ultimum. UV irradiation of the water reservoir reduced algal and biofilm growth and extended the lifespan of the system.

  18. Grain boundary effects on defect production and mechanical properties of irradiated nanocrystalline SiC

    SciTech Connect

    Jin Enze; Niu Lisha; Lin Enqiang; Song Xiaoxiong

    2012-05-15

    Grain boundaries (GBs) are known to play an important role in determining the mechanical and functional properties of nanocrystalline materials. In this study, we used molecular dynamics simulations to investigate the effects of damaged GBs on the mechanical properties of SiC that is irradiated by 10 keV Si atoms. The results reveal that irradiation promotes GB sliding and reduces the ability of GBs to block dislocations, which improves the deformation ability of nanocrystalline SiC. However, irradiation causes local rearrangements in disordered clusters and pinning of dislocations in the grain region, which restrains its deformation. These two mechanisms arise from the irradiation effects on GBs and grains, and these mechanisms compete in nanocrystalline SiC during irradiation. The irradiation effects on GBs dominate at low irradiation doses, and the effects on grains dominate at high doses; the result of these combined effects is a peak ductility of 0.09 dpa in nanocrystalline SiC.

  19. Effect of hepatic irradiation on the toxicity and pharmacokinetics of adriamycin in children

    SciTech Connect

    Holcenberg, J.S.; Kun, L.E.; Ring, B.J.; Evans, W.E.

    1981-07-01

    The effect of hepatic irradiation on adriamycin toxicity and pharmacokinetics was studied in 10 children who received adriamycin with concurrent abdominal irradiation for Wilms' tumor. Hepatic irradiation to 2400 to 2700 rad at 100 to 150 rad per fraction did not alter the clinical toxicity or plasma pharmacokinetics of adriamycin.

  20. Irradiation-Induced Thermal Effects in Alloyed Metal Fuel of Fast Reactors

    NASA Astrophysics Data System (ADS)

    Kryukov, F. N.; Nikitin, O. N.; Kuzmin, S. V.; Belyaeva, A. V.; Gilmutdinov, I. F.; Grin, P. I.; Zhemkov, I. Yu

    2017-01-01

    The paper presents the results of studying alloyed metal fuel after irradiation in a fast reactor. Determined is the mechanism of fuel irradiation swelling, mechanical interaction between fuel and cladding, and distribution of fission products. Experience gained in fuel properties and behavior under irradiation as well as in irradiation-induced thermal effects occurred in alloyed metal fuel provides for a fuel pin design to have a burnup not less than 20% h. a.

  1. Radiation effects in x-irradiated hydroxy compounds

    SciTech Connect

    Budzinski, E.E.; Potter, W.R.; Box, H.C.

    1980-01-15

    Radiation effects are compared in single crystals of xylitol, sorbitol, and dulcitol x-irradiated at 4.2 /sup 0/K. In xylitol and dulcitol, but not in sorbitol, a primary oxidation product is identified as an alkoxy radical. ENDOR measurements detected three proton hyperfine couplings associated with the alkoxy ESR absorption, one of which is attributed to a proton three bond lengths removed from the seat of unpaired spin density. Intermolecular trapping of electrons is observed in all three crystals. ENDOR measurements were made of the hyperfine couplings between the trapped electron and the hydroxy protons forming the trap.

  2. Radiation effects in x-irradiated hydroxy compounds

    NASA Astrophysics Data System (ADS)

    Budzinski, Edwin E.; Potter, William R.; Box, Harold C.

    1980-01-01

    Radiation effects are compared in single crystals of xylitol, sorbitol, and dulcitol x-irradiated at 4.2 °K. In xylitol and dulcitol, but not in sorbitol, a primary oxidation product is identified as an alkoxy radical. ENDOR measurements detected three proton hyperfine couplings associated with the alkoxy ESR absorption, one of which is attributed to a proton three bond lengths removed from the seat of unpaired spin density. Intermolecular trapping of electrons is observed in all three crystals. ENDOR measurements were made of the hyperfine couplings between the trapped electron and the hydroxy protons forming the trap.

  3. Electric field and temperature effects in irradiated MOSFETs

    NASA Astrophysics Data System (ADS)

    Silveira, M. A. G.; Santos, R. B. B.; Leite, F. G.; Araújo, N. E.; Cirne, K. H.; Melo, M. A. A.; Rallo, A.; Aguiar, Vitor. A. P.; Aguirre, F.; Macchione, E. L. A.; Added, N.; Medina, N. H.

    2016-07-01

    Electronic devices exposed to ionizing radiation exhibit degradation on their electrical characteristics, which may compromise the functionality of the device. Understanding the physical phenomena responsible for radiation damage, which may be specific to a particular technology, it is of extreme importance to develop methods for testing and recovering the devices. The aim of this work is to check the influence of thermal annealing processes and electric field applied during irradiation of Metal Oxide Semiconductor Field Effect Transistors (MOSFET) in total ionizing dose experiments analyzing the changes in the electrical parameters in these devices

  4. The irrelevant sound effect under articulatory suppression: is it a suffix effect?

    PubMed

    Hanley, J Richard; Hayes, Annabel

    2012-03-01

    An experiment is reported that investigates the relation between the suffix effect and the effect of irrelevant sound on the serial recall of short sequences of spoken material. The main issue was whether there is an effect of irrelevant sound under articulatory suppression in the presence of a spoken suffix. As in Hanley and Bakopoulou (2003), the irrelevant sound comprised speech that was presented during the retention interval. When a spoken suffix appeared at the end of the list, a significant effect of irrelevant sound remained when participants were able to rehearse list items. However, it disappeared under articulatory suppression. The effects of irrelevant sound remained significant under suppression when the suffix was an auditory tone but was confined to the final position of the serial position curve. These results parallel those reported by Jones, Macken, and Nicholls (2004) and Jones, Hughes, and Macken (2006) when they examined the effect of articulatory suppression on the phonological similarity effect. The results are consistent with Jones et al.'s (2006, 2004) view that an acoustic-perceptual representation of the terminal list items is the source of the effects of irrelevant sound and phonological similarity when they occur in the presence of articulatory suppression.

  5. Predicting Affective Information – An Evaluation of Repetition Suppression Effects

    PubMed Central

    Trapp, Sabrina; Kotz, Sonja A.

    2016-01-01

    Both theoretical proposals and empirical studies suggest that the brain interprets sensory input based on expectations to mitigate computational burden. However, as social beings, much of sensory input is affectively loaded – e.g., the smile of a partner, the critical voice of a boss, or the welcoming gesture of a friend. Given that affective information is highly complex and often ambiguous, building up expectations of upcoming affective sensory input may greatly contribute to its rapid and efficient processing. This review points to the role of affective information in the context of the ‘predictive brain’. It particularly focuses on repetition suppression (RS) effects that have recently been linked to prediction processes. The findings are interpreted as evidence for more pronounced prediction processes with affective material. Importantly, it is argued that bottom-up attention inflates the neural RS effect, and because affective stimuli tend to attract more bottom-up attention, it thereby particularly overshadows the magnitude of RS effects for this information. Finally, anxiety disorders, such as social phobia, are briefly discussed as manifestations of modulations in affective prediction. PMID:27667980

  6. Neutron irradiation of Am-241 effectively produces curium

    NASA Technical Reports Server (NTRS)

    Anderson, R. W.; Milstead, J.; Stewart, D. C.

    1967-01-01

    Computer study was made on the production of multicurie amounts of highly alpha-active curium 242 from americium 241 irradiation. The information available includes curium 242 yields, curium composition, irradiation data, and production techniques and safeguards.

  7. Effects of hydrogen isotopes in the irradiation damage of CLAM steel

    NASA Astrophysics Data System (ADS)

    Zhao, M. Z.; Liu, P. P.; Zhu, Y. M.; Wan, F. R.; He, Z. B.; Zhan, Q.

    2015-11-01

    The isotope effect of hydrogen in irradiation damage plays an important role in the development of reduced activation Ferritic/Martensitic steels in nuclear reactors. The evolutions of microstructures and mechanical properties of China low active martensitic (CLAM) steel subjected to hydrogen and deuterium ions irradiation are studied comparatively. Under the same irradiation conditions, larger size and smaller density of dislocation loops are generated by deuterium ion than by hydrogen ion. Irradiation hardening occurs under the ion irradiation and the hardening induced by hydrogen ion is higher than by deuterium ion. Moreover, the coarsening of M23C6 precipitates is observed, which can be explained by the solute drag mechanisms. It turns out that the coarsening induced by deuterium ion irradiation is more distinct than by hydrogen ion irradiation. No distinct variations for the compositions of M23C6 precipitates are found by a large number of statistical data after hydrogen isotopes irradiation.

  8. Combined effects of gamma-irradiation and modified atmosphere packaging on quality of some spices.

    PubMed

    Kirkin, Celale; Mitrevski, Blagoj; Gunes, Gurbuz; Marriott, Philip J

    2014-07-01

    Thyme (Thymus vidgaris L.), rosemary (Rosmarinus officinalis L.), black pepper (Piper nigrum L.) and cumin (Cuminum cyminum L.) in ground form were packaged in either air or 100% N2 and γ-irradiated at 3 different irradiation levels (7kGy, 12kGy, 17kGy). Total viable bacterial count, yeast and mould count, colour, essential oil yield and essential oil composition were determined. Microbial load was not detectable after 12kGy irradiation of all samples. Irradiation resulted in significant changes in colour values of rosemary and black pepper. The discolouration of the irradiated black pepper was lower in modified atmosphere packaging (MAP) compared to air packaging. Essential oil yield of irradiated black pepper and cumin was lower in air packaging compared to MAP. Gamma-irradiation generally decreased monoterpenes and increased oxygenated compounds, but the effect was lower in MAP. Overall, spices should be irradiated under an O2-free atmosphere to minimise quality deterioration.

  9. Spectroscopic study of energetic helium-ion irradiation effects on nuclear graphite tiles

    NASA Astrophysics Data System (ADS)

    Kim, Do Wan; Lee, K. W.; Choi, D. M.; Noh, S. J.; Kim, H. S.; Lee, Cheol Eui

    2016-02-01

    Helium ion-irradiation effects on the nuclear graphite tiles were studied in order to understand the structural modifications and damages that can be produced by fusion reaction in tokamaks. The surface morphological changes due to increasing dose of the irradiation were examined by the field-effect scanning electron microscopy, and X-ray photoelectron spectroscopy elucidated the changes in the shallow surface bonding configurations caused by the energetic irradiation. Raman spectroscopy revealed the structural defects and diamond-like carbon sites that increased with increasing irradiation dose, and the average inter-defect distance was found from the Raman peak intensities as a function of the irradiation dose.

  10. The effect of irradiation at low doses on human embryos and fetuses

    SciTech Connect

    Romanova, L.K.; Zhorova, E.S.

    1994-05-01

    Data about the biological effect of irradiation at low dose on prenatal human development have been reviewed. The effect of irradiation is observed either immediately after it or in the progeny, as consequences of irradiation affecting the embryo or fetus. Human embryos and fetuses are most sensitive to ionizing irradiation during the peaks of proliferative activity and cell differentiation. The concept has been formulated that any dose of irradiation, however low, can inflict damage to the embryo or fetus. Problems and perspectives of studies in this field are discussed.

  11. The protective effects of piceatannol from passion fruit (Passiflora edulis) seeds in UVB-irradiated keratinocytes.

    PubMed

    Maruki-Uchida, Hiroko; Kurita, Ikuko; Sugiyama, Kenkichi; Sai, Masahiko; Maeda, Kazuhisa; Ito, Tatsuhiko

    2013-01-01

    The use of naturally occurring botanicals with substantial antioxidant activity to prevent photoageing is receiving increasing attention. We have previously identified piceatannol and scirpusin B, which is a dimer of piceatannol, as strong antioxidants that are present in passion fruit (Passiflora edulis) seeds. In the present study, the effects of passion fruit seed extract, piceatannol, and scirpusin B on human keratinocytes were investigated. The passion fruit seed extract and piceatannol upregulated the glutathione (GSH) levels in keratinocytes in a dose-dependent manner, indicating that piceatannol is an active component of the passion fruit seed extract in keratinocytes. The pretreatment with piceatannol also suppressed the UVB-induced generation of reactive oxygen species (ROS) in the keratinocytes. In addition, the transfer of the medium from the UVB-irradiated keratinocytes to non-irradiated fibroblasts enhanced matrix-metalloproteinase (MMP)-1 activity, and this MMP-1 induction was reduced when the keratinocytes were pretreated with piceatannol. These results suggest that piceatannol attenuates the UVB-induced activity of MMP-1 along with a reduction of ROS generation in keratinocytes. Thus, piceatannol and passion fruit seed extract containing high amounts of piceatannol are potential anti-photoageing cosmetic ingredients.

  12. Gyroaverage effects on nontwist Hamiltonians: Separatrix reconnection and chaos suppression

    SciTech Connect

    Del-Castillo-Negrete, Diego B; Martinell, J.

    2012-01-01

    A study of finite Larmor radius (FLR) effects on E x B test particle chaotic transport in non-monotonic zonal flows with drift waves in magnetized plasmas is presented. Due to the non-monotonicity of the zonal flow, the Hamiltonian does not satisfy the twist condition. The electrostatic potential is modeled as a linear superposition of a zonal flow and the regular neutral modes of the Hasegawa-Mima equation. FLR effects are incorporated by gyro-averaging the E x B Hamiltonian. It is shown that there is a critical value of the Larmor radius for which the zonal flow transitions from a profile with one maximum to a profile with two maxima and a minimum. This bifurcation leads to the creation of additional shearless curves and resonances. The gyroaveraged nontwist Hamiltonian exhibits complex patterns of separatrix reconnection. A change in the Larmor radius can lead to heteroclinic-homoclinic bifurcations and dipole formation. For Larmor radii for which the zonal flow has bifurcated, double heteroclinic-heteroclinic, homoclinic-homoclinic and heteroclinic-homoclinic separatrix topologies are observed. It is also shown that chaotic transport is typically reduced as the Larmor radius increases. Poincare sections show that, for large enough Larmor radius, chaos can be practically suppressed. In particular, changes of the Larmor radius can restore the shearless curve.

  13. Suppressing magnetization exchange effects in stimulated-echo diffusion experiments.

    PubMed

    Pagès, Guilhem; Dvinskikh, Sergey V; Furó, István

    2013-09-01

    Exchange of nuclear magnetization between spin pools, either by chemical exchange or by cross-relaxation or both, has a significant influence on the signal attenuation in stimulated-echo-type pulsed field gradient experiments. Hence, in such cases the obtained molecular self-diffusion coefficients can carry a large systematic error. We propose a modified stimulated echo pulse sequence that contains T2-filters during the z-magnetization store period. We demonstrate, using a common theoretical description for chemical exchange and cross-relaxation, that these filters suppress the effects of exchange on the diffusional decay in that frequent case where one of the participating spin pools is immobile and exhibits a short T2. We demonstrate the performance of this experiment in an agarose/water gel. We posit that this new experiment has advantages over other approaches hitherto used, such as that consisting of measuring separately the magnetization exchange rate, if suitable by Goldman-Shen type experiments, and then correcting for exchange effects within the framework of a two-site exchange model. We also propose experiments based on selective decoupling and applicable in systems with no large T2 difference between the different spin pools.

  14. Crystallization of sputter-deposited amorphous Ge films by electron irradiation: Effect of low-flux pre-irradiation

    NASA Astrophysics Data System (ADS)

    Okugawa, M.; Nakamura, R.; Ishimaru, M.; Yasuda, H.; Numakura, H.

    2016-10-01

    We investigated the effect of low-flux electron irradiation with 125 keV to sputter-deposited amorphous germanium on the amorphous structure and electron-induced crystallization microstructure by TEM following our previous study on the effect of aging at room temperature. In samples aged for 3 days, coarse, spherical particles about 100 nm in diameter appear dominantly. By low-flux pre-irradiation to the samples, a reduction in the size and number of coarse particles, embedded in the matrix with fine nanograins of the diamond cubic structure, was noted with the increase in fluence. The crystal structure of these coarse particles was found to be not cubic but hexagonal. In samples aged for 4 months, a similar tendency was observed. In samples aged for 7 months, on the other hand, the homogeneous diamond cubic structured nanograins were unchanged by pre-irradiation. These results indicate that pre-irradiation as well as aging modifies the amorphous structure, preventing the appearance of a hexagonal phase. The elimination of a certain amount of medium-range ordered clusters by pre-irradiation, included in as-deposited samples and the samples aged for 4 months, apparently gives rise to a reduction in the size and number of coarse particles with a metastable hexagonal structure.

  15. Effective ultraviolet irradiation of platelet concentrates in teflon bags

    SciTech Connect

    Capon, S.M.; Sacher, R.A.; Deeg, H.J. )

    1990-10-01

    Several plastic materials used in blood storage were evaluated for their ability to transmit ultraviolet B (UVB) light. A plastic bag manufactured from sheets of transparent Teflon efficiently (78-86%) transmitted UVB light and was employed in subsequent functional studies of lymphocytes and platelets exposed to UVB light while contained in these bags. In vitro experiments showed a UVB dose-dependent abrogation of lymphocyte responder and stimulator functions, with concurrent preservation of platelet aggregation responses. In a phase I pilot study, UVB-treated platelet concentrates were administered to four bone marrow transplant recipients. Adverse effects attributable to the transfusions were not observed, and patients showed clinically effective transfusion responses. No patient developed lymphocytotoxic HLA or platelet antibodies. These studies suggest that platelets can be effectively irradiated with UVB light in a closed system. However, numerous variables, including container material, volume and composition of contents, steady exposure versus agitation, and exact UV wavelength, must be considered.

  16. Effects of mass loss for highly-irradiated giant planets

    NASA Astrophysics Data System (ADS)

    Hubbard, W. B.; Hattori, M. F.; Burrows, A.; Hubeny, I.; Sudarsky, D.

    2007-04-01

    We present calculations for the evolution and surviving mass of highly-irradiated extrasolar giant planets (EGPs) at orbital semimajor axes ranging from 0.023 to 0.057 AU using a generalized scaled theory for mass loss, together with new surface-condition grids for hot EGPs and a consistent treatment of tidal truncation. Theoretical estimates for the rate of energy-limited hydrogen escape from giant-planet atmospheres differ by two orders of magnitude, when one holds planetary mass, composition, and irradiation constant. Baraffe et al. [Baraffe, I., Selsis, F., Chabrier, G., Barman, T.S., Allard, F., Hauschildt, P.H., Lammer, H., 2004. Astron. Astrophys. 419, L13-L16] predict the highest rate, based on the theory of Lammer et al. [Lammer, H., Selsis, F., Ribas, I., Guinan, E.F., Bauer, S.J., Weiss, W.W., 2003. Astrophys. J. 598, L121-L124]. Scaling the theory of Watson et al. [Watson, A.J., Donahue, T.M., Walker, J.C.G., 1981. Icarus 48, 150-166] to parameters for a highly-irradiated exoplanet, we find an escape rate ˜10 lower than Baraffe's. With the scaled Watson theory we find modest mass loss, occurring early in the history of a hot EGP. In this theory, mass loss including the effect of Roche-lobe overflow becomes significant primarily for masses below a Saturn mass, for semimajor axes ⩾0.023 AU. This contrasts with the Baraffe model, where hot EGPs are claimed to be remnants of much more massive bodies, originally several times Jupiter and still losing substantial mass fractions at present.

  17. Effects of laser irradiation on the self-assembly of MnAs nanoparticles in a GaAs matrix

    SciTech Connect

    Hai, Pham Nam; Nomura, Wataru; Yatsui, Takashi; Ohtsu, Motoichi; Tanaka, Masaaki

    2012-11-05

    We investigate the effects of laser irradiation on the self-assembly of MnAs nanoparticles during solid-phase decomposition in a GaAs matrix. It is found that laser irradiation suppresses the growth of MnAs nanoparticles from small to large size, and that the median diameter D{sub 1} in the size distribution of small MnAs nanoparticles depends on the incident photon energy E following D{sub 1} {approx} E{sup -1/5}. We explain this behavior by the desorption of Mn atoms on the MnAs nanoparticle surface due to resonant optical absorption, in which incident photons excite intersubband electronic transitions between the quantized energy levels in the MnAs nanoparticles.

  18. Effect of self-ion irradiation on the microstructural changes of alloy EK-181 in annealed and severely deformed conditions

    NASA Astrophysics Data System (ADS)

    Aydogan, E.; Chen, T.; Gigax, J. G.; Chen, D.; Wang, X.; Dzhumaev, P. S.; Emelyanova, O. V.; Ganchenkova, M. G.; Kalin, B. A.; Leontiva-Smirnova, M.; Valiev, R. Z.; Enikeev, N. A.; Abramova, M. M.; Wu, Y.; Lo, W. Y.; Yang, Y.; Short, M.; Maloy, S. A.; Garner, F. A.; Shao, L.

    2017-04-01

    EK-181 is a low-activation ferritic/martensitic steel that is an attractive candidate for in-core component materials for both fast reactors and fusion reactors. To assess the effect of microstructural engineering on radiation response, two variants of EK-181 were studied: one in an annealed condition and the other subject to severe plastic deformation. These specimens were irradiated with 3.5 MeV Fe self-ions up to 400 peak displacements per atom (dpa) at temperatures ranging from 400 °C to 500 °C. The deformation did not suppress swelling over the whole irradiated region. Instead, deformed samples showed higher swelling in the near-surface region. Void swelling was found to be correlated with grain boundary instability. Significant grain growth occurred when steady-state void growth started.

  19. High doses of gamma radiation suppress allergic effect induced by food lectin

    NASA Astrophysics Data System (ADS)

    Vaz, Antônio F. M.; Souza, Marthyna P.; Vieira, Leucio D.; Aguiar, Jaciana S.; Silva, Teresinha G.; Medeiros, Paloma L.; Melo, Ana M. M. A.; Silva-Lucca, Rosemeire A.; Santana, Lucimeire A.; Oliva, Maria L. V.; Perez, Katia R.; Cuccovia, Iolanda M.; Coelho, Luana C. B. B.; Correia, Maria T. S.

    2013-04-01

    One of the most promising areas for the development of functional foods lies in the development of effective methods to reduce or eliminate food allergenicity, but few reports have summarized information concerning the progress made with food irradiation. In this study, we investigated the relationship between allergenicity and molecular structure of a food allergen after gamma irradiation and evaluate the profile of the allergic response to irradiated allergens. Cramoll, a lectin isolated from a bean and used as a food allergen, was irradiated and the possible structural changes were accompanied by spectrofluorimetry, circular dichroism and microcalorimetry. Subsequently, sensitized animals subjected to intragastric administration of non-irradiated and irradiated Cramoll were treated for 7 days. Then, body weight, leukocytes, cytokine profiles and histological parameters were also determined. Cramoll showed complete inhibition of intrinsic activity after high radiation doses. Changes in fluorescence and CD spectra with a simultaneous collapse of the tertiary structure followed by a pronounced decrease of native secondary structure were observed after irradiation. After oral challenge, sensitized mice demonstrate an association between Cramoll intake, body weight loss, eosinophilia, lymphocytic infiltrate in the gut and Eotaxin secretion. Irradiation significantly reduces, according to the dose, the effects observed by non-irradiated food allergens. We confirm that high-dose radiation may render protein food allergens innocuous by irreversibly compromising their molecular structure.

  20. Modification of the genetic effect of gamma irradiation by electric current

    SciTech Connect

    Grigor'eva, N.N.; Shakbazov, V.G.

    1985-09-01

    The authors study the effect of direct current of varying strength and polarity on the genetic damage due to gamma irradiation of Vicia faba seedlings. The modificational effect of direct current observed earlier is confirmed here. The extent and nature of this effect depends on the strength and polarity of the current as well as interval between irradiation and exposure to the electric field. Conditions having no effect on the irradiated seedlings, those protecting the cells from damage and enhancing the irradiation effect, are identified.

  1. Effects of proton beam irradiation on uveal melanomas: a comparative study of Ki-67 expression in irradiated versus non-irradiated melanomas

    PubMed Central

    Chiquet, C.; Grange, J.; Ayzac, L.; Chauvel, P.; Patricot, L.; Devouassoux-Shish..., M.

    2000-01-01

    AIMS—To assess the cellular proliferation using the monoclonal antibody Ki-67, in paraffin embedded uveal melanomas irradiated by proton beam, as well as in non-irradiated uveal melanomas.
METHODS—30 enucleated eyes were included for histopathological study and Ki-67 immunostaining. Patients were enucleated between 1991 and 1996 for uveal melanoma, 14 after proton beam irradiation and 16 without treatment (control group). The mean follow up period was 2.5 years after diagnosis and 1 year after enucleation.
RESULTS—A significant relation was found between Ki-67 score and mitotic index (r = 0.56, p = 0.001), histological largest tumour diameter (r = 0.38, p = 0.03), fibrosis (r = −0.35, p = 0.05), absence of tumoral pigmentation (p = 0.05), and presence of vascular thrombosis (p = 0.03). The Ki-67 score was significantly higher in the non-irradiated group (p = 0.01) and in the group of patients whose cause of enucleation was tumoral evolution (p = 0.005) compared with the group of patients enucleated after neovascular glaucoma. The Ki-67 score was very high in a case of orbital recurrence of uveal melanoma and metastatic death. 70% of metastasised tumours showed a Ki-67 score higher than the median value.
CONCLUSION—Ki-67 labelling is a reliable method of estimating the proliferative activity in uveal melanomas after proton beam irradiation. The Ki-67 score is significantly correlated with prognostic variables (mitotic index and histological largest tumour diameter), and with radiation effects after proton beam irradiation.

 PMID:10611107

  2. Effect of preliminary irradiation on the bond strength between a veneering composite and alloy.

    PubMed

    Matsumoto, Yoshifumi; Furuchi, Mika; Oshima, Akiko; Tanoue, Naomi; Koizumi, Hiroyasu; Matsumura, Hideo

    2010-01-01

    The shear bond strength of a veneering composite (Solidex) and silver-palladium-copper-gold alloy (Castwell M.C.12) was evaluated for different duration times and irradiance for preliminary photo-polymerization. A veneering composite was applied onto a cast disk. Preliminary photo irradiation was performed using different duration times or irradiance. After final polymerization, the bond strength and the spectral distribution of each curing unit were determined. Shear bond strength was significantly higher for 90 s (12.4 MPa), than that for 0 s (8.3 MPa). With regard to the effect of irradiance, that from Solidilite (11.4 MPa) was significantly higher than that from Sublite S at 3 cm (8.7 MPa). The irradiance of Hyper LII and Sublite S at 3 cm was higher than Sublite S at 15 cm or Solidilite unit. Long time irradiation and low intensity is effective for preliminary irradiation in order to enhance the bond strength.

  3. Effects of millimeter wave irradiation and equivalent thermal heating on the activity of individual neurons in the leech ganglion

    PubMed Central

    Romanenko, Sergii; Siegel, Peter H.; Wagenaar, Daniel A.

    2014-01-01

    Many of today's radiofrequency-emitting devices in telecommunication, telemedicine, transportation safety, and security/military applications use the millimeter wave (MMW) band (30–300 GHz). To evaluate the biological safety and possible applications of this radiofrequency band for neuroscience and neurology, we have investigated the physiological effects of low-intensity 60-GHz electromagnetic irradiation on individual neurons in the leech midbody ganglia. We applied incident power densities of 1, 2, and 4 mW/cm2 to the whole ganglion for a period of 1 min while recording the action potential with a standard sharp electrode electrophysiology setup. For comparison, the recognized U.S. safe exposure limit is 1 mW/cm2 for 6 min. During the exposure to MMWs and gradual bath heating at a rate of 0.04°C/s (2.4°C/min), the ganglionic neurons exhibited similar dose-dependent hyperpolarization of the plasma membrane and decrease in the action potential amplitude. However, narrowing of the action potential half-width during MMW irradiation at 4 mW/cm2 was 5 times more pronounced compared with that during equivalent bath heating of 0.6°C. Even more dramatic difference in the effects of MMW irradiation and bath heating was noted in the firing rate, which was suppressed at all applied MMW power densities and increased in a dose-dependent manner during gradual bath heating. The mechanism of enhanced narrowing of action potentials and suppressed firing by MMW irradiation, compared with that by gradual bath heating, is hypothesized to involve specific coupling of MMW energy with the neuronal plasma membrane. PMID:25122711

  4. Compton suppression gamma-counting: The effect of count rate

    USGS Publications Warehouse

    Millard, H.T.

    1984-01-01

    Past research has shown that anti-coincidence shielded Ge(Li) spectrometers enhanced the signal-to-background ratios for gamma-photopeaks, which are situated on high Compton backgrounds. Ordinarily, an anti- or non-coincidence spectrum (A) and a coincidence spectrum (C) are collected simultaneously with these systems. To be useful in neutron activation analysis (NAA), the fractions of the photopeak counts routed to the two spectra must be constant from sample to sample to variations must be corrected quantitatively. Most Compton suppression counting has been done at low count rate, but in NAA applications, count rates may be much higher. To operate over the wider dynamic range, the effect of count rate on the ratio of the photopeak counts in the two spectra (A/C) was studied. It was found that as the count rate increases, A/C decreases for gammas not coincident with other gammas from the same decay. For gammas coincident with other gammas, A/C increases to a maximum and then decreases. These results suggest that calibration curves are required to correct photopeak areas so quantitative data can be obtained at higher count rates. ?? 1984.

  5. The suppressive effects of aluminum chloride on the osteoblasts function.

    PubMed

    Zhu, Yanzhu; Xu, Feibo; Yan, Xijun; Miao, Liguang; Li, Haitao; Hu, Chongwei; Wang, Zhongying; Lian, Shizhen; Feng, Zhuo; Li, Yanfei

    2016-12-01

    Aluminum (Al) exposure impairs bone formation, and bone formation is mediated by the osteoblasts. But effects of Al on the osteoblasts function remain elusive. The osteoblasts were exposed to 0, 0.0252, 0.126, 0.252mg/mL AlCl3·6H2O for 24h. The osteoblasts viability, TGF-β1, BMP-2, IGF-I and Cbfα1 mRNA expressions, and GSH-Px and SOD activities, ROS concentration were determined. The osteoblasts ultrastructural features were also observed. The results showed that AlCl3 suppressed the osteoblasts viability, TGF-β1, BMP-2, IGF-I and Cbfα1 mRNA expressions, GSH-Px and SOD activities, and elevated ROS concentration compared with the CG. The ultrastructural features of osteoblasts in the HG showed mitochondrial swelling, foam-like structure, uneven distribution of chromatin, incomplete cell membrane and cytoplasm spillover compared with the CG. It indicates that AlCl3 inhibits osteoblasts viability, growth regulation factors mRNA expressions, anti-oxidative function, and damaged the osteoblasts histology structure, impairing the osteoblasts function.

  6. Effects of electron beam irradiation on polyamide 12 with fiberglass reinforcement

    NASA Astrophysics Data System (ADS)

    Jeun, Joon-Pyo; Shin, Bum-Sik; Kim, Hyun-Bin; Nho, Young-Chang; Kang, Phil-Hyun

    2010-06-01

    In the present study, the effects of electron beam irradiation of polyamide 12 (PA12) with fiberglass reinforcement on the thermal and wear properties were investigated. Electron beam irradiation of PA 12 was carried out over a range of irradiation doses (100-600 kGy) in air. The gel formation in the presence of a curing agent was dependent on the radiation doses. The thermal properties of irradiated PA 12 were studied in the temperature region 50-250° C to observe the changes in the melting point with radiation dose. The dimensional stability was significantly increased by electron beam irradiation and the related crosslinking of the PA 12.

  7. The effect of neutron irradiation on silicon carbide fibers

    SciTech Connect

    Newsome, G.A.

    1997-01-01

    Nine types of SiC fiber have been exposed to neutron radiation in the Advanced Test Reactor at 250 C for various lengths of time ranging from 83 to 128 days. The effects of these exposures have been initially determined using scanning electron microscopy. The fibers tested were Nicalon{trademark} CG, Tyranno, Hi-Nicalon{trademark}, Dow Corning SiC, Carborundum SiC, Textron SCS-6, polymethysilane (PMS) derived SiC from the University of Michigan, and two types of MER SiC fiber. This covers a range of fibers from widely used commercial fibers to developmental fibers. Consistent with previous radiation experiments, Nicalon fiber was severely degraded by the neutron irradiation. Similarly, Tyranno suffered severe degradation. The more advanced fibers which approach the composition and properties of SiC performed well under irradiation. Of these, the Carborundum SiC fiber appeared to perform the best. The Hi-Nicalon and Dow Corning Fibers exhibited good general stability, but also appear to have some surface roughening. The MER fibers and the Textron SCS-6 fibers both had carbon cores which adversely influenced the overall stability of the fibers.

  8. Mutagenic effects of heavy ion irradiation on rice seeds

    NASA Astrophysics Data System (ADS)

    Xu, Xue; Liu, Binmei; Zhang, Lili; Wu, Yuejin

    2012-11-01

    Three varieties of rice seeds were subjected to irradiation using low-energy and medium-energy ions. The damage and mutations induced by the ions were examined. In addition, genetic analysis and gene mapping of spotted leaf (spl) mutants were performed. Low-energy ions had no significant influence on germination, survival or seedling height, except for the survival of Nipponbare. Medium-energy ions had a significant influence on germination and survival but had no significant effect on seedling height. In the low-energy group, among 60,000 M2 plants, 2823 putative morphological mutants were found, and the mutation frequency was approximately 4.71%. In the medium-energy group, 3132 putative morphological mutants were found, and the mutation frequency was approximately 5.22%. Five spl mutants (spl29-spl33) were obtained by ion irradiation, and the heredity of the spl mutants was stable. The characteristics of the spl mutants were found, by genetic analysis and preliminary mapping, to be controlled by a single recessive gene, and spl30 and spl33 were found to be new lesion-mimic mutants.

  9. Effect of microplasma irradiation on skin barrier function

    NASA Astrophysics Data System (ADS)

    Shimizu, Kazuo; Tran, Nhat An; Blajan, Marius

    2015-09-01

    This study investigates the feasibility of atmospheric-pressure argon microplasma irradiation (AAMI) to promote drug delivery through skin. Yucatan micropig skin was used as a biological object for evaluation of in vitro percutaneous absorption. The changes in lipids, proteins and water content of the pig stratum corneum (SC) after AAMI were compared to those of a tape stripping test (TST) and plasma jet irradiation (PJI) using attenuated total reflection-Fourier transform infrared spectroscopy analysis. The significant reduction in the methylene stretching modes absorbance resulted in the disturbance in the SC lipids caused by AAMI was observed at 2850 and 2920 cm-1. Moreover, as the result of TST, trans-epidermal water loss (TEWL) after both AAMI and PJI were also increased, that could lead to a decrease of barrier function of SC, and could enhance the transdermal absorption of drugs. Under the conditions of this study, TEWL value of 5 minutes AAMI (35.92 +/- 3.48 g/m2h) was approximately the same as that value of 10 times TST (34.30 +/- 3.54 g/m2h), that makes the effect of these manipulations on the surfaces is considered to be at the same levels. Furthermore, unlike the obtained microscopic observation from PJI, there was no thermal damage observed on the skins after AAMI.

  10. Effect of irradiation parameters on defect aggregation during thermal annealing of LiF irradiated with swift ions and electrons

    SciTech Connect

    Schwartz, K.; Neumann, R.; Trautmann, C.; Volkov, A. E.; Sorokin, M. V.

    2010-10-01

    Absorption spectroscopy were performed to study the effects of thermal annealing on the aggregation of color centers in LiF crystals irradiated with different ions between carbon and uranium of megaelectron volt-gigaelectron volt energy. The beam parameters such as energy, energy loss, and fluence have a pronounced influence on the initial defect composition and concentration as well as their evolution upon thermal annealing. A distinct phenomenon was observed, viz., the enhancement of F{sub n} centers for annealing temperatures between 500 and 700 K, followed by Li colloid formation above 700 K. The phenomenon requires specific irradiation conditions whereas the formation of Mg colloids from Mg impurities occurs in all irradiated crystals. The mechanisms of annealing and colloid formation are discussed.

  11. Detection of gamma-irradiation effect on DNA and protein using magnetic sensor and cyclic voltammetry.

    PubMed

    Park, Duck-Gun; Song, Hoon; Kishore, M B; Vértesy, G; Lee, Duk-Hyun

    2013-11-01

    In this study, a magnetic sensor utilizing Planar Hall Resistance (PHR) and cyclic Voltammetry (CV) for detecting the radiation effect was fabricated. Specifically, we applied in parallel a PHR sensor and CV device to monitor the irradiation effect on DNA and protein respectively. Through parallel measurements, we demonstrated that the PHR sensor and CV are sensitive enough to measure irradiation effect. The PHR voltage decreased by magnetic nanobead labeled DNA was slightly recovered after gamma ray irradiation. The behavior of cdk inhibitor protein p21 having a sandwich structure of Au/protein G/Ab/Ag/Ab was checked by monitoring the cyclic Voltammetry signal in analyzing the gamma ray irradiation effect.

  12. Anti-inflammatory effect of selenium nanoparticles on the inflammation induced in irradiated rats.

    PubMed

    El-Ghazaly, M A; Fadel, N; Rashed, E; El-Batal, A; Kenawy, S A

    2017-02-01

    Selenium (Se) has been reported to possess anti-inflammatory properties, but its bioavailability and toxicity are considerable limiting factors. The present study aimed to investigate the possible anti-inflammatory and analgesic effects of selenium nanoparticles (Nano-Se) on inflammation induced in irradiated rats. Paw volume and nociceptive threshold were measured in carrageenan-induced paw edema and hyperalgesia model. Leukocytic count, tumor necrosis factor-α (TNF-α), prostaglandin E2 (PGE2), thiobarbituric acid reactive substances (TBAR), and total nitrate/nitrite (NOx) were estimated in the exudate collected from 6 day old air pouch model. Irradiated rats were exposed to 6 Gy gamma (γ)-irradiation. Nano-Se were administered orally in a dose of 2.55 mg/kg once before carrageenan injection in the first model and twice in the second model. The paw volume but not the nociceptive response produced by carrageenan in irradiated rats was higher than that induced in non-irradiated rats. Nano-Se were effective in reducing the paw volume in non-irradiated and irradiated rats but it did not alter the nociceptive threshold. The inflammation induced in irradiated rats increased all the estimated parameters in the exudate whereas; Nano-Se decreased their elevation in non-irradiated and irradiated rats. Nano-Se possess a potential anti-inflammatory activity on inflammation induced in irradiated rats.

  13. Carbon-Ion Irradiation Suppresses Migration and Invasiveness of Human Pancreatic Carcinoma Cells MIAPaCa-2 via Rac1 and RhoA Degradation

    SciTech Connect

    Fujita, Mayumi; Imadome, Kaori; Shoji, Yoshimi; Isozaki, Tetsurou; Endo, Satoshi; Yamada, Shigeru; Imai, Takashi

    2015-09-01

    Purpose: To investigate the mechanisms underlying the inhibition of cancer cell migration and invasion by carbon (C)-ion irradiation. Methods and Materials: Human pancreatic cancer cells MIAPaCa-2, AsPC-1, and BxPC-3 were treated by x-ray (4 Gy) or C-ion (0.5, 1, 2, or 4 Gy) irradiation, and their migration and invasion were assessed 2 days later. The levels of guanosine triphosphate (GTP)-bound Rac1 and RhoA were determined by the active GTPase pull-down assay with or without a proteasome inhibitor, and the binding of E3 ubiquitin ligase to GTP-bound Rac1 was examined by immunoprecipitation. Results: Carbon-ion irradiation reduced the levels of GTP-bound Rac1 and RhoA, 2 major regulators of cell motility, in MIAPaCa-2 cells and GTP-bound Rac1 in AsPC-1 and BxPC-3 cells. Proteasome inhibition reversed the effect, indicating that C-ion irradiation induced Rac1 and RhoA degradation via the ubiquitin (Ub)-proteasome pathway. E3 Ub ligase X-linked inhibitor of apoptosis protein (XIAP), which directly targets Rac1, was selectively induced in C-ion–irradiated MIAPaCa-2 cells and coprecipitated with GTP-bound Rac1 in C-ion–irradiated cells, which was associated with Rac1 ubiquitination. Cell migration and invasion reduced by C-ion radiation were restored by short interfering RNA–mediated XIAP knockdown, indicating that XIAP is involved in C-ion–induced inhibition of cell motility. Conclusion: In contrast to x-ray irradiation, C-ion treatment inhibited the activity of Rac1 and RhoA in MIAPaCa-2 cells and Rac1 in AsPC-1 and BxPC-3 cells via Ub-mediated proteasomal degradation, thereby blocking the motility of these pancreatic cancer cells.

  14. Nonthermal effect of microwave irradiation in nonaqueous enzymatic esterification.

    PubMed

    Wan, Hui-da; Sun, Shi-yu; Hu, Xue-yi; Xia, Yong-mei

    2012-03-01

    Microwave has nonthermal effects on enzymatic reactions, mainly caused by the polarities of the solvents and substrates. In this experiment, a model reaction with caprylic acid and butanol that was catalyzed by lipase from Mucor miehei in alkanes or arenes was employed to investigate the nonthermal effect in nonaqueous enzymatic esterification. With the comparison of the esterification carried by conventional heating and consecutive microwave irradiation, the positive nonthermal effect on the initial reaction rates was found substrate concentration-dependent and could be vanished ostensibly when the substrate concentration was over 2.0 mol L(-1). The polar parameter log P well correlates the solvent polarity with the microwave effect, comparing to dielectric constant and assayed solvatochromic solvent polarity parameters. The log P rule presented in conventional heating-enzymatic esterification still fits in the microwaved enzymatic esterification. Alkanes or arenes with higher log P provided positive nonthermal effect in the range of 2 ≤ log P ≤ 4, but yielded a dramatic decrement after log P = 4. Isomers of same log P with higher dielectric constant received stronger positive nonthermal effect. With lower substrate concentration, the total log P of the reaction mixture has no obvious functional relation with the microwave effect.

  15. Risk of Eye Damage from the Wavelength-Dependent Biologically Effective UVB Spectrum Irradiances

    PubMed Central

    Wang, Fang; Gao, Qian; Hu, Liwen; Gao, Na; Ge, Tiantian; Yu, Jiaming; Liu, Yang

    2012-01-01

    A number of previous studies have discussed the risk of eye damage from broadband ultraviolet (UV) radiation. As the biologically damaging effectiveness of UV irradiation on the human body is known to be wavelength-dependent, it is necessary to study the distribution of the UV spectral irradiance. In order to quantify the ocular biologically effective UV (UVBE) irradiance exposure of different wavelengths and assess the risk of eye damage, UV exposure values were measured at Sanya, China (18.4° N, 109.7°E, altitude 18 m), using a manikin and a dual-detector spectrometer to measure simultaneously the ocular exposure and ambient UV spectral irradiance data and solar elevation angle (SEA) range (approximately 7°–85°). The present study uses the ocular UV spectral irradiance exposure weighted with the action spectra for photokeratitis, photoconjunctivitis and cataracts to calculate the ocular UVBE irradiance exposure for photokeratitis (UVBEpker), photoconjunctivitis (UVBEpcon) and cataracts (UVBEcat). We found that the ocular exposure to UV irradiance is strongest in the 30°–60° SEA range when ∼50% of ocular exposure to UV irradiance on a summer’s day is received. In the 7°–30° SEA range, all the biologically highly effective wavelengths of UVBEpker, UVBEpcon and UVBEcat irradiances are at 300 nm. However, in other SEA ranges the biologically highly effective wavelengths of UVBEpker, UVBEpcon and UVBEcat irradiances are different, corresponding to 311 nm, 300 nm and 307 nm, respectively. PMID:23284960

  16. The effect of electron beam irradiation on preparation of sago starch/polyvinyl alcohol foams

    NASA Astrophysics Data System (ADS)

    Wongsuban, Benchamaporn; Muhammad, Kharidah; Ghazali, Zulkafli; Hashim, Kamaruddin; Ali Hassan, Muhammad

    2003-10-01

    Blends of sago starch (SS)/polyvinyl alcohol (PVA) were irradiated with doses ranging from 10 to 30 kGy. Foams were then produced from these irradiated blends using a microwave. Changes in the degree of crosslinking, gel strength, thermal stability morphology of blends and linear expansion of foam with increasing irradiation doses were subsequently investigated. It was observed that the degree of crosslinking was important in maximizing the positive effect on foams produced. The gel strength of SS/PVA blends was affected by the irradiation. The crosslinking by the irradiation enhanced the thermal stability of SS/PVA blends. The results also revealed that the highest linear expansion of foams could be produced by irradiation blends at 15 kGy. Changes in blend morphology were observed upon irradiation.

  17. Irradiation of rainbow trout at early life stages results in trans-generational effects including the induction of a bystander effect in non-irradiated fish.

    PubMed

    Smith, Richard W; Seymour, Colin B; Moccia, Richard D; Mothersill, Carmel E

    2016-02-01

    The bystander effect, a non-targeted effect (NTE) of radiation, which describes the response by non-irradiated organisms to signals emitted by irradiated organisms, has been documented in a number of fish species. However transgenerational effects of radiation (including NTE) have yet to be studied in fish. Therefore rainbow trout, which were irradiated as eggs at 48h after fertilisation, eyed eggs, yolk sac larvae or first feeders, were bred to generate a F1 generation and these F1 fish were bred to generate a F2 generation. F1 and F2 fish were swam with non-irradiated bystander fish. Media from explants of F1 eyed eggs, F1 one year old fish gill and F1 two year old fish gill and spleen samples, and F2 two year old gill and spleen samples, as well as from bystander eggs/fish, was used to treat a reporter cell line, which was then assayed for changes in cellular survival/growth. The results were complex and dependent on irradiation history, age (in the case of the F1 generation), and were tissue specific. For example, irradiation of one parent often resulted in effects not seen with irradiation of both parents. This suggests that, unlike mammals, in certain circumstances maternal and paternal irradiation may be equally important. This study also showed that trout can induce a bystander effect 2 generations after irradiation, which further emphasises the importance of the bystander effect in aquatic radiobiology. Given the complex community structure in aquatic ecosystems, these results may have significant implications for environmental radiological protection.

  18. Effects of Electron Beam and Microwave Irradiation on Human Blood Proteins

    SciTech Connect

    Martin, Diana I.; Craciun, Gabriela D.; Manaila, Elena N.; Ighigeanu, Daniel I.; Iacob, Nicusor I.; Oproiu, Constantin V.; Stan, Dana E.; Radu, Roxana R.; Margaritescu, Irina D.; Chirita, Doru I.

    2007-04-23

    The effects of separated and combined accelerated electron beam (EB) of 6.23 MeV and microwave (MW) of 2.45GHz irradiation on proteins in samples of human serum, human plasma and human integral blood are presented. Also, it was studied the effect of separate and combined EB and MW irradiation on proteins irradiated in samples of human integral blood, without and in the presence of a synthetic compound solution (S.C.S.) which is expected to exhibit various biological actions, such as to diminish or to increase the irradiation effects.

  19. Effects of Electron Beam and Microwave Irradiation on Human Blood Proteins

    NASA Astrophysics Data System (ADS)

    Martin, Diana I.; Stan, Dana E.; Radu, Roxana R.; Cinca, Sabin A.; Margaritescu, Irina D.; Chirita, Doru I.; Craciun, Gabriela D.; Manaila, Elena N.; Ighigeanu, Daniel I.; Iacob, Nicusor I.; Oproiu, Constantin V.

    2007-04-01

    The effects of separated and combined accelerated electron beam (EB) of 6.23 MeV and microwave (MW) of 2.45GHz irradiation on proteins in samples of human serum, human plasma and human integral blood are presented. Also, it was studied the effect of separate and combined EB and MW irradiation on proteins irradiated in samples of human integral blood, without and in the presence of a synthetic compound solution (S.C.S.) which is expected to exhibit various biological actions, such as to diminish or to increase the irradiation effects.

  20. The effect of full/partial UV-irradiation of TiO2 films on altering the behavior of fibrinogen and platelets.

    PubMed

    Chen, Jiang; Zhao, Ansha; Chen, Huiqing; Liao, Yuzhen; Yang, Ping; Sun, Hong; Huang, Nan

    2014-10-01

    Titanium oxide (TiO2) thin film is a potential candidate for the surface modification of blood-contacting devices. It has previously been reported that ultraviolet light (UV) irradiation could alter the biocompatibility of TiO2 films. However, the effect of UV-irradiated TiO2 films on blood compatibility has rarely been reported. This study attempts to determine: (1) whether UV-irradiation of TiO2 films enhances their blood compatibility, (2) the interaction between UV-irradiated TiO2 films, fibrinogen (Fgn), and platelets, especially how Fgn and platelets respond to the geometry of the partially UV-irradiated TiO2 film surface. Anatase TiO2 films were subjected to full and partial UV-irradiation. Full UV-irradiation improved the blood compatibility of TiO2 films by almost completely inhibiting the adhesion and activation of platelets, strongly suppressing the adsorption and conformational change of Fgn, and preventing the formation of fibrin fibers. Additionally, hemolysis was not observed. After partial UV-irradiation, the regions where Fgn adsorption was reduced (Fgn-dark regions) were formed at regions where UV-irradiation had occurred, but were extended in comparison with the UV-irradiated regions, which could be related to the generation and diffusion of reactive oxygen species (ROS) on the UV-irradiated TiO2 surface. It is worthwhile to study how ROS altered the nature of TiO2 films, thereby enhancing their blood compatibility. Furthermore, platelets were found adhering to the Fgn-adsorbed regions (Fgn-bright regions) selectively, suggesting that the inhibition of platelet adhesion could be related to the suppression of Fgn adsorption on the UV-irradiated TiO2 surface. It was also noted that platelet surface coverage (Sp) was not linearly correlated with Fgn-bright region surface coverage (Sf), which indicated that the adhesion and spreading of platelets were regulated by both Sf and the geometry of Fgn.

  1. Cellular immunological effects of laser irradiation and immunoadjuvant application

    NASA Astrophysics Data System (ADS)

    Chen, Wei R.; Mohamed, Abdiwahab; Naylor, Mark F.; Bartels, Kenneth E.; Ritchey, Jerry W.; Liu, Hong; Nordquist, Robert E.

    2007-02-01

    Immune system is critical in the fight against cancer. Particular important is the responses through immune cells that regulate immunological functions. Certain cytokines enhance cancer immunity (such as IL12 and interferon gamma) and others interfere or impede cancer immunity (such as IL10). The clinical outcome can be linked to the balance of these cytokines, such as IL10 to IL12 ratio. Effective treatments often reduce the IL10:IL12 ratio, indicating higher levels of the cancer fighting IL12. To enhance immune responses, a combination of laser irradiation and concurrent use of immunostimulants has been applied for the treatment of tumors. In a recent study, an 805-nm laser in conjunction with indocyanine green (ICG) has been used to treat EMT6 mammary tumors in mice. An immunoadjuvant, glycated chitosan (GC), was intratumoral injected after the laser irradiation. Our preliminary results showed that tumor-bearing mice treated either with the immunoadjuvant alone or with the combination of laser and immunoadjuvant had lower IL10:IL12 ratios than animals that received no treatment. This may play an important in the treatment to decrease tumor size and to increase survival times of mice. Cellular activities after laser-ICG-GC treatment of DBMA-4 mammary tumors in rats also showed infiltration of immune cells to the treatment sites, indicating a possible induced immunity. The combination of laser treatment and immunotherapy has been used to treat late-stage melanoma patients; the responses, both treated primary tumors and the metastases, to the treatment have been promising. The histology of two patients, before and after treatment, is presented to show the effects of this novel treatment method.

  2. Information channel effects on women intention to purchase irradiated food in Korea

    NASA Astrophysics Data System (ADS)

    Byun, Myung-Woo; Oh, Sang-Hee; Kim, Jae-Hun; Yoon, Yohan; Park, Seong-Cheol; Kim, Hak-Soo; Kim, Soon-Bok; Han, Sang-Bae; Lee, Ju-Woon

    2009-07-01

    Since the first irradiated food was approved and commercialized in 1987, most of Koreans still do not accept the irradiated food until now. It is reasoned that there are the ambiguous fear of nuclear technology and the confusion between irradiated food and radioactive-contaminated food. This investigation was carried out to examine the acknowledgement of irradiated food in Korean housewives and to study how to enhance the intention of purchasing the irradiated food. About 600 Korean housewives participated in the survey on the irradiated food in 2007, more than two-thirds of them were not aware of irradiated food. One hundred and fifty-four women who had known of irradiated food were subjected to an experiment for the source of information about irradiated food (e.g., lecture by an expert, video-watching and book-reading) in order to explore which type of information channel is the most effective in eliciting purchase intention. The result showed that the women group who had heard the lecture by an expert indicated the highest intention to purchase irradiated food, followed by the video-watching and the book-reading groups. In addition, the acceptance of the irradiated food had shown to lead the support for nuclear industry.

  3. Effect of gamma irradiation on the conversion of ginsenoside Rb1 to Rg3

    NASA Astrophysics Data System (ADS)

    Kim, Jae-Hun; Kwon, Sun-Kyu; Sung, Nak-Yun; Jung, Pil-Mun; Choi, Jong-il; Kim, Jae-Kyung; Sharma, Arun K.; Lee, Ju-Woon

    2012-08-01

    Ginsenosides, the most important secondary metabolites in ginseng, have various biological activities. Many studies have focused on the conversion of one of the major ginsenosides, Rb1, to the more active minor ginsenoside, Rg3. This study was carried out to investigate the effect of gamma irradiation on the conversion of Rb1 to Rg3. Rb1 solutions were gamma-irradiated at doses of 10 and 30 kGy and analyzed by high performance liquid chromatography (HPLC). HPLC chromatograms showed a decreased content of Rb1 with increasing irradiation dose, but the content of Rg3 was increased. The highest content of Rg3 was present in the 30 kGy-irradiated Rb1 sample. The cytotoxic effects tested in cancer cell lines were increased in the gamma-irradiated group. Therefore, these results suggest that gamma irradiation can be an effective method for the conversion of the ginsenoside Rb1 to Rg3.

  4. Effects of the SARM ACP-105 on rotorod performance and cued fear conditioning in sham-irradiated and irradiated female mice.

    PubMed

    Dayger, Catherine; Villasana, Laura; Pfankuch, Timothy; Davis, Matthew; Raber, Jacob

    2011-03-24

    Female mice are more susceptible to radiation-induced cognitive changes than male mice. Previously, we showed that, in female mice, androgens antagonize age-related cognitive decline in aged wild-type mice and androgens and selective androgen receptor modulators (SARMs) antagonize cognitive changes induced by human apolipoprotein E4, a risk factor for developing age-related cognitive decline. In this study, the potential effects of the SARM ACP-105 were assessed in female mice that were either sham-irradiated or irradiated with ¹³⁷Cesium at a dose of 10Gy. Behavioral testing started 2 weeks following irradiation. Irradiation impaired sensorimotor function in vehicle-treated mice but not in ACP-105-treated mice. Irradiation impaired cued fear conditioning and ACP-105 enhanced fear conditioning in sham-irradiated and irradiated mice. When immunoreactivity for microtubule-associated protein 2 was assessed in the cortex of sham-irradiated mice, there was a brain area × ACP-105 interaction. While ACP-105 reduced MAP-2 immunoreactivity in the sensorimotor cortex, there was a trend towards increased MAP-2 immunoreactivity in the enthorhinal cortex. No effect on MAP-2 immunoreactivity was seen in the irradiated cortex or sham-irradiated or irradiated hippocampus. Thus, there are relatively early radiation-induced behavioral changes in female mice and reduced MAP-2 levels in the sensorimotor cortex following ACP-105 treatment might contribute to enhanced rotorod performance.

  5. Effects of HZE irradiation on chemical neurotransmission in rodent hippocampus

    NASA Astrophysics Data System (ADS)

    Machida, Mayumi

    Space radiation represents a significant risk to the CNS (central nervous system) during space missions. Most harmful are the HZE (high mass, highly charged (Z), high energy) particles, e.g. 56Fe, which possess high ionizing ability, dense energy deposition pattern, and high penetrance. Accumulating evidence suggests that radiation has significant impact on cognitive functions. In ground-base experiments, HZE radiation induces pronounced deficits in hippocampus dependent learning and memory in rodents. However, the mechanisms underlying these impairments are mostly unknown. Exposure to HZE radiation elevates the level of oxidation, resulting in cell loss, tissue damage and functional deficits through direct ionization and generation of reactive oxygen species (ROS). When hippocampal slices were exposed to ROS, neuronal excitability was reduced. My preliminary results showed enhanced radio-vulnerability of the hippocampus and reduction in basal and depolarization-evoked [3H]-norepinephrine release after HZE exposure. These results raised the possibility that HZE radiation deteriorates cognitive function through radiation-induced impairments in hippocampal chemical neurotransmission, the hypothesis of this dissertation. In Aim 1 I have focused on the effects of HZE radiation on release of major neurotransmitter systems in the hippocampus. I have further extended my research on the levels of receptors of these systems in Aim 2. In Aim 3, I have studied the level of oxidation in membranes of my samples. My research reveals that HZE radiation significantly reduces hyperosmotic sucrose evoked [3H]-glutamate and [14C]-GABA release both three and six months post irradiation. The same radiation regimen also significantly enhances oxidative stress as indicated by increased levels of lipid peroxidation in the hippocampus, suggesting that increased levels of lipid peroxidation may play a role in reduction of neurotransmitter release. HZE radiation also significantly reduces

  6. Radioprotective effect of Lyophyllum decastes and the effect on immunological functions in irradiated mice.

    PubMed

    Nakamura, Takashi; Itokawa, Yuka; Tajima, Masayuki; Ukawa, Yuuichi; Cho, Kwang-Ho; Choi, Jung-Sook; Ishid, Torao; Gu, Yeunhwa

    2007-03-01

    In this study, to explore the radiation protection effects of Lyophyllum Decastes Sing (LDS), a hot distilled-water extract of LDS was orally administered at a dosage of 250mg/kg every other day for a period of 2 weeks in irradiated mice. An automatic blood cell counter was used to measure white blood cells (lymphocytes, monocyte, and granulocytes) one day before X-ray irradiation, and 3 hours, 12 hours, 24 hours, 3 days, 7 days, 15 days and 30 days after irradiation. The Dunnett test was used to examine statistical significance of differences. The peripheral blood cell counts in the Lyophyllum-administered non-irradiation group revealed an increase in the numbers of leukocytes, lymphocytes and monocytes. For 2 Gy whole body radiation, a significant statistical difference was found between the X-ray group and the Lyophyllum plus X-ray group in the numbers of leukocytes, lymphocytes and monocytes. The results suggest that Lyophyllum restrains blood cell-count falling after irradiation, which is probably mediated at least in part by hemopoietic function, and NK and LAK activities seems to play a role in preventing secondary infections associated with irradiation.

  7. Effect of oral administration of Lactobacillus plantarum HY7714 on epidermal hydration in ultraviolet B-irradiated hairless mice.

    PubMed

    Ra, Jehyeon; Lee, Dong Eun; Kim, Sung Hwan; Jeong, Ji-Woong; Ku, Hyung Keun; Kim, Tae-Youl; Choi, Il-Dong; Jeung, Woonhee; Sim, Jae-Hun; Ahn, Young-Tae

    2014-12-28

    In this study, we evaluated the effect of Lactobacillus plantarum HY7714 on skin hydration in human dermal fibroblasts and in hairless mice. In Hs68 cells, L. plantarum HY7714 not only increased the serine palmitoyltransferase (SPT) mRNA level, but also decreased the ceramidase mRNA level. In order to confirm the hydrating effects of L. plantarum HY7714 in vivo, we orally administered vehicle or L. plantarum HY7714 at a dose of 1 × 10(9) CFU/day to hairless mice for 8 weeks. In hairless mice, L. plantarum HY7714 decreased UVB-induced epidermal thickness. In addition, we found that L. plantarum HY7714 administration suppressed the increase in transepidermal water loss and decrease in skin hydration, which reflects barrier function fluctuations following UV irradiation. In particular, L. plantarum HY7714 administration increased the ceramide level compared with that in the UVB group. In the experiment on SPT and ceramidase mRNA expressions, L. plantarum HY7714 administration improved the reduction in SPT mRNA levels and suppressed the increase in ceramidase mRNA levels caused by UVB in the hairless mice skins. Collectively, these results suggest that L. plantarum HY7714 can be a potential candidate for preserving skin hydration levels against UV irradiation.

  8. Biofumigation and soil amendment effects on cotton root rot suppression

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This serious disease of cotton grown in southwest USA can be suppressed to varying degrees. Our results indicate the following: improved plant nutrition with certain chelated trace elements; soil applications of slow release fungicides; preplant banding of high rates of powdered elemental S; use o...

  9. Sequential Analysis of the Numerical Stroop Effect Reveals Response Suppression

    ERIC Educational Resources Information Center

    Kadosh, Roi Cohen; Gevers, Wim; Notebaert, Wim

    2011-01-01

    Automatic processing of irrelevant stimulus dimensions has been demonstrated in a variety of tasks. Previous studies have shown that conflict between relevant and irrelevant dimensions can be reduced when a feature of the irrelevant dimension is repeated. The specific level at which the automatic process is suppressed (e.g., perceptual repetition,…

  10. The Effect of Neutron Irradiation on the Fracture Toughness of Graphite

    SciTech Connect

    Burchell, Timothy D; Strizak, Joe P

    2012-01-01

    As part of our irradiated graphite recycle program a small quantity of PCEA grade graphite was irradiated in the High Flux Isotope Reactor (HFIR) at ORNL. The graphite will provide the raw material for future recycle experiments. The geometry of the irradiated graphite allowed us to study the effects of neutron irradiation on the Critical Stress Intensity Factor, KIc, of graphite. The specimens where irradiated in two groups of 6 at an irradiation temperature of 900 C in rabbit capsules to doses of 6.6 and 10.2 DPA, respectively. Following a full suite of pre-and post-irradiation examination, which included dimensions, mass, electrical resistivity, elastic constants, and thermal expansion (to 800 C) the samples were notched and tested to determine their KIc using the newly approved ATSM test method for SENB fracture toughness of graphite. Here we report the irradiation induced changes in the dimensions, elastic constants, resistivity, and coefficient of thermal expansion of PCEA graphite. Moreover, irradiation induced changes in the Critical Stress Intensity Factor, KIc, or fracture toughness, are reported and discussed. Very little work on the effect of neutron irradiation on the fracture toughness of graphite has previously be performed or reported.

  11. Trait anxiety, working memory capacity, and the effectiveness of memory suppression.

    PubMed

    Waldhauser, Gerd T; Johansson, Mikael; Bäckström, Martin; Mecklinger, Axel

    2011-02-01

    We aimed at replicating the finding that humans are able to suppress unwanted memories, and tested whether this ability varies with individual differences in working memory capacity, trait anxiety and defensiveness. In a think/no-think experiment, participants either recalled or suppressed previously learned words for 0, 8 or 16 times. Suppression did not have an overall detrimental effect on later recall performance. However, higher recall rates after repeated suppression were exclusively predicted by higher trait anxiety. These results are discussed in relation to current theories on anxiety and executive control.

  12. Effects of Atmospheric Air Plasma Irradiation on pH of Water

    NASA Astrophysics Data System (ADS)

    Sarinont, Thapanut; Koga, Kazunori; Kitazaki, Satoshi; Uchida, Giichirou; Hayashi, Nobuya; Shiratani, Masaharu

    We have studied the effects of atmospheric air plasma irradiation to water using a scalable dielectric barrier discharge device. Measurements of the pH of water treated by the plasmas have shown the pH decreases due to peroxide molecules generated by plasma irradiation and depends on material of water container. We also found this plasma treated water has little effect on the growth enhancement on Radish sprouts compare with plasma irradiation on dry seeds and the plasma irradiation can affect them through the water buffer of 0.2 mm in thickness.

  13. Effect of electron beam irradiation sterilization on the biomedical poly (octene-co-ethylene)/polypropylene films

    NASA Astrophysics Data System (ADS)

    Luan, Shifang; Shi, Hengchong; Yao, Zhanhai; Wang, Jianwei; Song, Yongxian; Yin, Jinghua

    2010-05-01

    The effect of electron beam irradiation with the dose ranging from 15 to 40 kGy on poly (octene-co-ethylene) (POE)/polypropylene (PP) films was investigated. Wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), yellowness index testing and mechanical performance measurement were applied to characterize the films. It demonstrated that crystalline structure exhibited little change, and degree of crystallinity slightly change under the irradiation treatment. Irradiation brought about oxidation of the films, forming hydroxyl groups of the peroxides and carbonyl groups. Tensile properties become worse as irradiation dose increased. Electron beam irradiation with the dose of 15-40 kGy has little effect on crystalline performance and a little influence for the POE/PP films, indicating a good irradiation resistance.

  14. The effect of neutron irradiation on the mechanical properties of C/SiC composites

    NASA Astrophysics Data System (ADS)

    Shih, Chunghao; Katoh, Yutai; Snead, Lance L.; Steinbeck, John

    2013-08-01

    The effects of neutron irradiation to 3.5 and 9.5 dpa at 730 °C on a 2D plain woven carbon fiber reinforced polymer derived SiC matrix composite are presented. For both fluences, the irradiation caused in-plane contraction and trans-plane expansion. Irradiation also caused substantial reduction in composite flexural strength (-54%) and increase in flexural tangent modulus (+85%). The extents of dimensional/mechanical property changes were greater for the higher fluence irradiated samples. Those changes suggest the instability of the polymer derived SiC matrix following irradiation. The nature of the mechanical property changes suggest increased clamping stress between the fiber and the matrix. The composite property changes are explained in terms of irradiation effects on composite constituents and are compared with carbon fiber reinforced carbon matrix composite as a reference material.

  15. Effect of Electron Beam Irradiation on the Tensile Properties of Carbon Nanotubes Sheets and Yarns

    NASA Technical Reports Server (NTRS)

    Williams, Tiffany S.; Miller, Sandi G.; Baker, James S.; McCorkle, Linda S.; Meador, Michael A.

    2013-01-01

    Carbon nanotube sheets and yarns were irradiated using electron beam (e-beam) energy to determine the effect of irradiation dose on the tensile properties. Results showed that a slight change in tensile strength occurred after irradiating as-received CNT sheets for 20 minutes, and a slight decrease in tensile strength as the irradiation time approached 90 minutes. On the other hand, the addition of small molecules to the CNT sheet surface had a greater effect on the tensile properties of e-beam irradiated CNT sheets. Some functionalized CNT sheets displayed up to a 57% increase in tensile strength following 90 minutes of e-beam exposure. In addition, as-received CNT yarns showed a significant increase in tensile strength as the irradiation time increased.

  16. The effect of neutron irradiation on the mechanical properties of C/SiC composites

    SciTech Connect

    Shih, Chunghao; Katoh, Yutai; Snead, Lance Lewis; Steinbeck, John

    2013-01-01

    The effects of neutron irradiation to 3.5 and 9.5 dpa at 730 C on a 2D plain woven carbon fiber reinforced polymer derived SiC matrix composite are presented. For both fluences, the irradiation caused in-plane contraction and trans-plane expansion. Irradiation also caused substantial reduction in composite flexural strength (54%) and increase in flexural tangent modulus (+85%). The extents of dimensional/ mechanical property changes were greater for the higher fluence irradiated samples. Those changes suggest the instability of the polymer derived SiC matrix following irradiation. The nature of the mechanical property changes suggest increased clamping stress between the fiber and the matrix. The composite property changes are explained in terms of irradiation effects on composite constituents and are compared with carbon fiber reinforced carbon matrix composite as a reference material.

  17. Effect of Low-Dose Irradiation on Pregnant Mouse Hemopoiesis

    DTIC Science & Technology

    1980-07-10

    simiLhr for the nonirradiated 200 + ~ 180 *-4 9 IRRADIATED 180 16 ---.U)" IRRADIATED Z 160 --DAY 10.5 ’U~14O 2LU -- 140- - 21 120- 24? 100 -20 z 80 16...3 *%~ 60.~ "" ,,,," 40 V5 1 20 z 0 0 0 • -U 9 IRRADIATED 12 ’-" ’ PIRRADIATED M , DAY 10.S 20 10 4 - -0- 0 0.5 1.0 TOTAL BODY IRRADIATION (Gy) Fit S... plastia dot cultures taininag 50 000 bone marMrw or pe’mse Plier 0. 1 at. Irradiation and Haemopoiesis in Pregnancy 133 in 12 6 0. 8 4 M -2 m 6 0 IO

  18. Effects of thymus irradiation on the immune competence of T cells after total-lymphoid irradiation

    SciTech Connect

    Palathumpat, V.C.; Vandeputte, M.M.; Waer, M. )

    1990-07-01

    Spleen cells from mice receiving TLI, with or without thymus shielding, were investigated for in vitro and in vivo defects. At 4-6 weeks after irradiation spleen cells of both groups showed a normal number of Thy1 (T cells), L3T4 (CD4 positive T cells) cells, and an absence of natural suppressor cells. Splenocytes of the nonthymic shielded TLI group were not able to mount either a normal in vitro response (in MLR or PHA) or an in vivo graft-versus-host-disease reaction when injected into lethally irradiated adult allogeneic recipients or into neonatal F1 hybrids. This was in contrast to the normal immune capacity of spleen cells from the thymus shielded group that gave normal MLR and PHA tests in vitro and provoked GVHD in vivo. Thymuses recovered from mice receiving TLI with or without thymic shielding were however equally efficient in restoring the immune capacity after transplantation into neonatally thymectomized mice as measured by the PHA assay. Thymic irradiation is therefore necessary but not sufficient for creating long-lasting immune defects after TLI.

  19. Controversial effects of low level laser irradiation on the proliferation of human osteoblasts

    NASA Astrophysics Data System (ADS)

    Bölükbaşı Ateş, Gamze; Ak, Ayşe.; Garipcan, Bora; Yüksel, Šahru; Gülsoy, Murat

    2015-03-01

    Low level laser irradiation (LLLI) is the application of red or near infrared lasers irradiating between 600-1100 nm with an output power of 1-500 mW. Several researches indicate that LLLI modulates cellular mechanisms and leads to enhance proliferation. Although the biological mechanisms are not fully understood, it is known that the effects depend on several parameters such as wavelength, irradiation duration, energy level, beam type and energy density. The aim of this study is to investigate the effect of low level laser irradiation at varying energy densities with two different wavelengths (635 nm and 809 nm) on the proliferation of human osteoblasts in vitro. The cells are seeded on 96 well plates (105cells/well) and after 24 h incubation cells are irradiated at energy densities 0.5 J/cm2, 1 J/cm2 and 2 J/cm2. Cell viability test is applied after 24 h, 48 h and 72 h in order to examine effects of laser irradiation on osteoblast proliferation. 635 nm light irradiation did not appear to have significant effect on the proliferation of osteoblasts as compared to the control. On the other hand, 809 nm laser irradiation caused significant (p ≤ 0.01) biostimulation effect on the osteoblast cell cultures at 48 h and 72 h. In conclusion, irradiation of both wavelengths did not cause any cytotoxic effects. 809 nm light irradiation can promote proliferation of human osteoblasts in vitro. On the other hand, 635 nm light irradiation has no positive effect on osteoblast proliferation. As a result, LLLI applied using different wavelengths on the same cell type may lead to different biological effects.

  20. Effects of irradiation source and dose level on quality characteristics of processed meat products

    NASA Astrophysics Data System (ADS)

    Ham, Youn-Kyung; Kim, Hyun-Wook; Hwang, Ko-Eun; Song, Dong-Heon; Kim, Yong-Jae; Choi, Yun-Sang; Song, Beom-Seok; Park, Jong-Heum; Kim, Cheon-Jei

    2017-01-01

    The effect of irradiation source (gamma-ray, electron-beam, and X-ray) and dose levels on the physicochemical, organoleptic and microbial properties of cooked beef patties and pork sausages was studied, during 10 days of storage at 30±1 °C. The processed meat products were irradiated at 0, 2.5, 5, 7.5, and 10 kGy by three different irradiation sources. The pH of cooked beef patties and pork sausages was unaffected by irradiation sources or their doses. The redness of beef patties linearly decreased with increasing dose level (P<0.05), obviously by e-beam irradiation compared to gamma-ray and X-ray (P<0.05). The redness of pork sausages was increased by gamma-ray irradiation, whereas it decreased by e-beam irradiation depending on absorbed dose level. No significant changes in overall acceptability were observed for pork sausages regardless of irradiation source (P>0.05), while gamma-ray irradiated beef patties showed significantly decreased overall acceptability in a dose-dependent manner (P<0.05). Lipid oxidation of samples was accelerated by irradiation depending on irradiation sources and dose levels during storage at 30 °C. E-beam reduced total aerobic bacteria of beef patties more effectively, while gamma-ray considerably decreased microbes in pork sausages as irradiation dose increased. The results of this study indicate that quality attributes of meat products, in particular color, lipid oxidation, and microbial properties are significantly influenced by the irradiation sources.

  1. Redox nanoparticle therapeutics to cancer--increase in therapeutic effect of doxorubicin, suppressing its adverse effect.

    PubMed

    Yoshitomi, Toru; Ozaki, Yuki; Thangavel, Sindhu; Nagasaki, Yukio

    2013-11-28

    The ultimate goal of cancer chemotherapy is to achieve a cure without causing any adverse effects. We have developed a pH-sensitive redox nanoparticle (RNP(N)), which disintegrates under acidic conditions and exposes nitroxide radicals, leading to strongly scavenging reactive oxygen species (ROS). After intravenous administration of RNP(N) to tumor bearing mice, it effectively accumulated in tumors due to the leaky neovascular and immature lymphatic system and scavenged ROS, resulting in suppression of inflammation and activation of NF-кB, after disintegration of RNP(N) in the tumors. Pre-administration of RNP(N) prior to treatments with anticancer agents, doxorubicin, to tumor-bearing mice significantly suppressed the progression of tumor size, compared to low-molecular weight 4-hydroxy-TEMPO. Interestingly, the administration of RNP(N) suppressed adverse effects of doxorubicin to normal organs due to the scavenging ROS and suppression of inflammation, which was confirmed by reduction in lactate dehydrogenase and creatine phosphokinase activities in plasma. RNP(N) is thus anticipated as a novel and ideal adjuvant for cancer chemotherapy.

  2. High total dose proton irradiation effects on silicon NPN rf power transistors

    SciTech Connect

    Bharathi, M. N.; Praveen, K. C.; Prakash, A. P. Gnana; Pushpa, N.

    2014-04-24

    The effects of 3 MeV proton irradiation on the I-V characteristics of NPN rf power transistors were studied in the dose range of 100 Krad to 100 Mrad. The different electrical characteristics like Gummel, current gain and output characteristics were systematically studied before and after irradiation. The recovery in the I-V characteristics of irradiated NPN BJTs were studied by isochronal and isothermal annealing methods.

  3. High total dose proton irradiation effects on silicon NPN rf power transistors

    NASA Astrophysics Data System (ADS)

    Bharathi, M. N.; Praveen, K. C.; Pushpa, N.; Prakash, A. P. Gnana

    2014-04-01

    The effects of 3 MeV proton irradiation on the I-V characteristics of NPN rf power transistors were studied in the dose range of 100 Krad to 100 Mrad. The different electrical characteristics like Gummel, current gain and output characteristics were systematically studied before and after irradiation. The recovery in the I-V characteristics of irradiated NPN BJTs were studied by isochronal and isothermal annealing methods.

  4. Electron irradiation effect on bubble formation and growth in a sodium borosilicate glass

    SciTech Connect

    Chen, X.; Birtcher, R. C.; Donnelly, S. E.

    2000-02-08

    In this study, the authors studied simultaneous and intermittent electron irradiation effects on bubble growth in a simple sodium borosilicate glass during Xe ion implantation at 200 C. Simultaneous electron irradiation increases the average bubble size in the glass. This enhanced diffusion is also shown by the migration of Xe from bubbles into the matrix when the sample is irradiated by an electron beam after the Xe implantation.

  5. Effect of gamma irradiation on the physiological activity of Korean soybean fermented foods, Chungkookjang and Doenjang

    NASA Astrophysics Data System (ADS)

    Byun, Myung-Woo; Son, Jun-Ho; Yook, Hong-Sun; Jo, Cheorun; Kim, Dong-Ho

    2002-06-01

    Effects of gamma irradiation on the physiological activity of Korean soybean fermented foods were investigated. Chungkookjang, the whole cooked soybean product and Doenjang, soybean paste were purchased and irradiated at 5, 10 and 20 kGy of absorbed doses. The physiological activity was evaluated by angiotensin converting enzyme inhibition, xanthine oxidase inhibition, tyrosinase inhibition and radical scavenging ability and results indicated that at 10 kGy or below did not show any significant change on physiological activities by irradiation.

  6. 40 CFR Appendix A to Subpart Wwww... - Test Method for Determining Vapor Suppressant Effectiveness

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... organic HAP emission factor equations in Table 1 to this subpart require that the vapor suppressant... into the appropriate organic HAP emission factor equation. The vapor suppressant effectiveness factor... organic HAP emissions factor equations in Table 1 to this subpart to generate emission factors....

  7. 40 CFR Appendix A to Subpart Wwww... - Test Method for Determining Vapor Suppressant Effectiveness

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... organic HAP emission factor equations in Table 1 to this subpart require that the vapor suppressant... into the appropriate organic HAP emission factor equation. The vapor suppressant effectiveness factor... organic HAP emissions factor equations in Table 1 to this subpart to generate emission factors....

  8. 40 CFR Appendix A to Subpart Wwww... - Test Method for Determining Vapor Suppressant Effectiveness

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... organic HAP emission factor equations in Table 1 to this subpart require that the vapor suppressant... into the appropriate organic HAP emission factor equation. The vapor suppressant effectiveness factor... organic HAP emissions factor equations in Table 1 to this subpart to generate emission factors....

  9. Suppressive and Facilitative Effects of Shock Intensity and Interresponse Times Followed by Shock

    ERIC Educational Resources Information Center

    Everly, Jessica B.; Perone, Michael

    2012-01-01

    Although response-dependent shock often suppresses responding, response facilitation can occur. In two experiments, we examined the suppressive and facilitative effects of shock by manipulating shock intensity and the interresponse times that produced shock. Rats' lever presses were reinforced on a variable-interval 40-s schedule of food…

  10. Effects of gamma irradiation on the yields of volatile extracts of Angelica gigas Nakai

    NASA Astrophysics Data System (ADS)

    Seo, Hye-Young; Kim, Jun-Hyoung; Song, Hyun-Pa; Kim, Dong-Ho; Byun, Myung-Woo; Kwon, Joog-Ho; Kim, Kyong-Su

    2007-11-01

    The study was carried out to determine the effects of gamma irradiation on the volatile flavor components including essential oils, of Angelica gigas Nakai. The volatile organic compounds from non- and irradiated A. gigas Nakai at doses of 1, 3, 5, 10 and 20 kGy were extracted by a simultaneous steam distillation and extraction (SDE) method and identified by GC/MS analysis. A total of 116 compounds were identified and quantified from non- and irradiated A. gigas Nakai. The major volatile compounds were identified 2,4,6-trimethyl heptane, α-pinene, camphene, α-limonene, β-eudesmol, α-murrolene and sphatulenol. Among these compounds, the amount of essential oils in non-irradiated sample were 77.13%, and the irradiated samples at doses of 1, 3, 5, 10 and 20 kGy were 84.98%, 83.70%, 83.94%, 82.84% and 82.58%, respectively. Oxygenated terpenes such as β-eudesmol, α-eudesmol, and verbenone were increased after irradiation but did not correlate with the irradiation dose. The yields of active substances such as essential oil were increased after irradiation; however, the yields of essential oils and the irradiation dose were not correlated. Thus, the profile of composition volatiles of A. gigas Nakai did not change with irradiation.

  11. Effects of gamma irradiation on chemical, microbial quality and shelf life of shrimp

    NASA Astrophysics Data System (ADS)

    Hocaoğlu, Aslı; Sükrü Demirci, Ahmet; Gümüs, Tuncay; Demirci, Mehmet

    2012-12-01

    In the present study the combined effect of gamma irradiation (1, 3 and 5 kGy) and storage at two temperatures: refrigeration (+4 °C) and frozen (-18 °C), on the shelf-life extension of fresh shrimp meat was investigated. The study was based on microbiological and physicochemical changes occuring in the shrimp samples. Total volatile base nitrogen values and trimethylamine values for irradiated shrimp samples were significantly lower than non-irradiated samples at both storage temperatures, and the rate of decrease was more pronounced in samples irradiated at the higher dose (p<0.05). Thiobarbituric acid values for irradiated shrimp samples were significantly higher than non-irradiated samples at both storage temperatures (p<0.05). pH values of shrimp samples were affected significantly by both irradiating dose and storage temperatures (p<0.05). Microbial counts for non-irradiated shrimp samples were higher than the respective irradiated samples at both storage temperatures (p<0.05). The results revealed that irradiation at high dose (5 kGy) might enhance lipid oxidation, although the growth of microorganisms and protein oxidation was inhibited.

  12. Calibrated photostimulated luminescence is an effective approach to identify irradiated orange during storage

    NASA Astrophysics Data System (ADS)

    Jo, Yunhee; Sanyal, Bhaskar; Chung, Namhyeok; Lee, Hyun-Gyu; Park, Yunji; Park, Hae-Jun; Kwon, Joong-Ho

    2015-06-01

    Photostimulated luminescence (PSL) has been employed as a fast screening method for various irradiated foods. In this study the potential use of PSL was evaluated to identify oranges irradiated with gamma ray, electron beam and X-ray (0-2 kGy) and stored under different conditions for 6 weeks. The effects of light conditions (natural light, artificial light, and dark) and storage temperatures (4 and 20 °C) on PSL photon counts (PCs) during post-irradiation periods were studied. Non-irradiated samples always showed negative values of PCs, while irradiated oranges exhibited intermediate results after first PSL measurements. However, the irradiated samples had much higher PCs. The PCs of all the samples declined as the storage time increased. Calibrated second PSL measurements showed PSL ratio <10 for the irradiated samples after 3 weeks of irradiation confirming their irradiation status in all the storage conditions. Calibrated PSL and sample storage in dark at 4 °C were found out to be most suitable approaches to identify irradiated oranges during storage.

  13. Effect of electron beam irradiation on PMMA films

    SciTech Connect

    Tiwari, Pragya; Srivastava, A. K.; Khattak, B. Q.; Verma, Suveer; Upadhyay, Anuj; Sinha, A. K.; Ganguli, Tapas; Lodha, G. S.; Deb, S. K.

    2012-06-05

    Polymethyl methacrylate (PMMA) is characterized for electron beam interactions in the resist layer in lithographic applications. PMMA thin films (free standing) were prepared by solvent casting method. These films were irradiated with 30keV electron beam at different doses. Structural and chemical properties of the films were studied by means of X-ray diffraction and Fourier transform infra-red (FTIR) spectroscopy The XRD results showed that the amorphization increases with electron beam irradiation dose. FTIR spectroscopic analysis reveals that electron beam irradiation promotes the scission of carbonyl group and depletes hydrogen and converts polymeric structure into hydrogen depleted carbon network.

  14. Effect of crossed beams irradiation on parametric instabilities

    SciTech Connect

    Labaune, C., Ecole Polytechnique, France

    1998-04-27

    Modification of the growth of scattering processes in the case of multiple beam irradiation compared to single beam irradiation has been investigated in a preformed plasma using Thomson scattrering of a short wavelength probe beam, and spectral and temporal analysis of reflected and transmitted light. First observations of the reduction of the amplitude of ion acoustic waves associated with stimulated Brillouin scattering, amplification of the amplitude of electron plasma waves associated with stimulated Raman scattering, and transfer of energy between crqssing beams with same frequency in a flowing plasma under crossed beam irradiation are reported.

  15. Renal dysfunction after total body irradiation: Dose-effect relationship

    SciTech Connect

    Kal, Henk B. . E-mail: H.B.Kal@UMCUtrecht.nl; Kempen-Harteveld, M. Loes van

    2006-07-15

    Purpose: Late complications related to total body irradiation (TBI) as part of the conditioning regimen for hematopoietic stem cell transplantation have been increasingly noted. We reviewed and compared the results of treatments with various TBI regimens and tried to derive a dose-effect relationship for the endpoint of late renal dysfunction. The aim was to find the tolerance dose for the kidney when TBI is performed. Methods and Materials: A literature search was performed using PubMed for articles reporting late renal dysfunction. For intercomparison, the various TBI regimens were normalized using the linear-quadratic model, and biologically effective doses (BEDs) were calculated. Results: Eleven reports were found describing the frequency of renal dysfunction after TBI. The frequency of renal dysfunction as a function of the BED was obtained. For BED >16 Gy an increase in the frequency of dysfunction was observed. Conclusions: The tolerance BED for kidney tissue undergoing TBI is about 16 Gy. This BED can be realized with highly fractionated TBI (e.g., 6 x 1.7 Gy or 9 x 1.2 Gy at dose rates >5 cGy/min). To prevent late renal dysfunction, the TBI regimens with BED values >16 Gy (almost all found in published reports) should be applied with appropriate shielding of the kidneys.

  16. Effect of gamma irradiation on bacteriophages used as viral indicators.

    PubMed

    Jebri, Sihem; Hmaied, Fatma; Jofre, Juan; MariemYahya; Mendez, Javier; Barkallah, Insaf; Hamdi, Moktar

    2013-07-01

    This study aimed to examine the susceptibility of indicator bacteriophages towards γ-radiation to evaluate their appropriateness as viral indicators for water quality control. The effects of γ-radiation on naturally occurring somatic coliphages, F-specific coliphages and Escherichia coli were examined in raw sewage and sewage sludge. As well, the effects of radiation on bacteriophages ΦX174 and MS2, and E. coli all grown in the laboratory and seeded in distilled water, autoclaved raw sewage and a 1% peptone solution were evaluated. The inactivation of E. coli was fairly similar in all matrices. In contrast, inactivation of bacteriophages was significantly greater in distilled water than in the other matrices. These results showed the great influence of the matrix characteristics on virus inactivation. Somatic coliphages in raw sewage and sewage sludge and ΦX174 in autoclaved sewage were inactivated similarly and were far more resistant than F-specific coliphages, MS2 and E. coli. As well, F-specific RNA bacteriophages in raw sewage and sewage sludge and MS2 in autoclaved sewage were inactivated similarly and were more resistant than E. coli. In contrast, MS2 was more susceptible to γ-radiation than E. coli in distilled water. Our results showed that ΦX174 is a suitable indicator for estimating virus inactivation by γ-irradiation and corroborate the use of somatic coliphages to survey the viral quality of treated water and sludges.

  17. Effect of gamma irradiation on viscosity reduction of cereal porridges for improving energy density

    NASA Astrophysics Data System (ADS)

    Lee, Ju-Woon; Kim, Jae-Hun; Oh, Sang-Hee; Byun, Eui-Hong; Yook, Hong-Sun; Kim, Mee-Ree; Kim, Kwan-Soo; Byun, Myung-Woo

    2008-03-01

    Cereal porridges have low energy and nutrient density because of its viscosity. The objective of the present study was to evaluate the effect of irradiation on the reduction of viscosity and on the increasing solid content of cereal porridge. Four cereals, wheat, rice, maize (the normal starchy type) and waxy rice, were used in this study. The porridge with 3000 cP was individually prepared from cereal flour, gamma-irradiated at 20 kGy and tested. Gamma irradiation of 20 kGy was allowed that the high viscous and rigid cereal porridges turned into semi-liquid consistencies. The solid contents of all porridges could increase by irradiation, compared with non-irradiated ones. No significant differences of starch digestibility were observed in all cereal porridge samples. The results indicated that gamma irradiation might be helpful for improving energy density of cereal porridge with acceptable consistency.

  18. The Irradiation Effect of a Simultaneous Laser and Electron Dual-beam on Void Formation

    PubMed Central

    Yang, Zhanbing; Watanabe, Seiichi; Kato, Takahiko

    2013-01-01

    Randomly distributed lattice point defects such as supersaturated vacancies (SVs) and Frenkel-pairs (FPs, an interstitial and a vacancy) can be simultaneously introduced into the crystal by energetic beam irradiation in outer space and/or nuclear reactors, but their behavior has not been fully understood. Using a high-voltage electron microscope equipped with a laser (laser-HVEM), we show the striking effects of simultaneous laser-electron (photon-electron) dual-beam irradiation on void formation. Our results reveal that during laser-electron sequential irradiation, pre-laser irradiation enhanced void nucleation and subsequent electron irradiation enhanced void growth. However, the laser-electron dual-beam irradiation was analyzed to depress void swelling remarkably because the recombination of SVs and interstitials was enhanced. The results provide insight into the mechanism underlying the dual-beam radiation-induced depression of void swelling in solids. PMID:23383371

  19. Effects of γ-irradiation on phenolics content, antioxidant activity and physicochemical properties of whole grainrice

    NASA Astrophysics Data System (ADS)

    Shao, Yafang; Tang, Fufu; Xu, Feifei; Wang, Yuefei; Bao, Jinsong

    2013-04-01

    Three rice genotypes with different color were gamma irradiated at a dose of 2, 4, 6, 8and 10 kGy. The aim of this study was to investigate the effect of gamma irradiation on the phenolics content and the antioxidant activity, as well as physicochemical properties of whole grain rice. The bound phenolics content in all the genotypes were significantly increased with the increase of dose of irradiation. Gamma irradiation at high dose significantly increased the free, bound and total antioxidant activities of three rice genotypes except for the free antioxidant activities of red rice. Though the color parameters were slightly changed, these changes could not be visibly identified. Rapid visco-analyzer (RVA) viscosities and gel hardness decreased continuously with the increase of the irradiation doses. It is suggested that gamma irradiation enhanced the antioxidant potential and eating quality of whole grainrice.

  20. Proton irradiation effects on the thermoelectric properties in single-crystalline Bi nanowires

    SciTech Connect

    Chang, Taehoo; Kim, Jeongmin; Song, Min-Jung; Lee, Wooyoung

    2015-05-15

    The effects of proton irradiation on the thermoelectric properties of Bi nanowires (Bi-NWs) were investigated. Single crystalline Bi-NWs were grown by the on-film formation of nanowires method. The devices based on individual Bi-NWs were irradiated with protons at different energies. The total number of displaced atoms was estimated using the Kinchin-Pease displacement model. The electric conductivity and Seebeck coefficient in the Bi-NW devices were investigated before and after proton irradiation at different temperatures. Although the Seebeck coefficient remained stable at various irradiation energies, the electrical conductivity significantly declined with increasing proton energy up to 40 MeV.

  1. Effect of irradiation and storage on the antioxidative activity of cashew nuts

    NASA Astrophysics Data System (ADS)

    Sajilata, M. G.; Singhal, R. S.

    2006-02-01

    Food irradiation, a cold process employed for preservation of food has been studied extensively for its beneficial and undesirable effects on food constituents. Since nuts have been shown to contain several antioxidants, and ionizing irradiation is known to result in the formation of free radicals, investigation on the antioxidative potential of cashew nuts after irradiation and subsequent storage was undertaken by assessing their ability to inhibit lipid peroxidation using the 1,3-diethyl-2-thiobarbituric acid (DETBA) assay. Irradiation at 0.25-1.00 kGy and subsequent storage was found to considerably reduce antioxidative activity in the cashew nuts.

  2. The effect of electron irradiation on structural properties of cobalt nanotubes

    NASA Astrophysics Data System (ADS)

    Kozlovskii, A. L.; Shlimas, D. I.; Zdorovets, M. V.; Kadyrzhanov, K. K.

    2016-10-01

    Cobalt nanotubes were fabricated by template synthesis in the pores of track membranes based on polyethylene terephthalate; modified by electron irradiation; and studied by scanning electronic microscopy, energy-dispersive analysis, and X-ray diffraction analysis. It was found that the resistivity of Co nanotubes dropped by 16.7 and 21.6% after electron irradiation with a dose of 50 and 100 kGy, respectively. It was demonstrated that the change in conductive properties is associated with the rearrangement of crystal structure after electron irradiation owing to the suppression of influence of the metastable β-Co phase and an increase in the degree of texturing in the <100> direction.

  3. Effect of gamma-irradiation on the molecular properties of myoglobin.

    PubMed

    Lee, Yongwoo; Song, Kyung Bin

    2002-11-30

    To elucidate the effect of gamma-irradiation on the molecular properties of myoglobin, the secondary and tertiary structures, as well as the molecular weight size of the protein, were examined after irradiation at various irradiation doses. Gamma-irradiation of myoglobin solutions caused the disruption of the ordered structure of the protein molecules, as well as degradation, crosslinking, and aggregation of the polypeptide chains. A SDSPAGE study indicated that irradiation caused initial fragmentation of the proteins and subsequent aggregation, due to cross-linking of the protein molecules. The effect of irradiation on the protein was more significant at lower protein concentrations. Ascorbic acid protected against the degradation and aggregation of proteins by scavenging oxygen radicals that are produced by irradiation. A circular dichroism study showed that an increase of the irradiation decreased the alpha-helical content of myoglobin with a concurrent increase of the aperiodic structure content. Fluorescence spectroscopy indicated that irradiation increased the emission intensity that was excited at 280 nm.

  4. Effect of γ-irradiation on structure and physico-chemical properties of Amorphophallus paeoniifolius starch.

    PubMed

    Reddy, Chagam Koteswara; Suriya, M; Vidya, P V; Vijina, K; Haripriya, Sundaramoorthy

    2015-08-01

    Gamma irradiation is one of the effective techniques able to alter structure and its properties of starch. In this research, the effect of modification in terms of molecular structure and physico-chemical properties of Amorphophallus paeoniifolius starch by γ-irradiation using (60)Co as γ-source at doses of 5, 10, 15, 20 and 25 kGy with dose rate 2 kGy/h was studied. Morphology of native and irradiated starches under scanning electron microscope revealed that granules are round, elliptical and polygonal in shape with smooth surfaces; no cracking or roughness was noted on irradiated starches. Amylose content, pH, swelling power of the starches and syneresis of the gelatinized starch were significantly decreased by irradiation; while carboxyl content, solubility, light transmittance and water absorption capacity of the starch granules were raised with increased dose of irradiation. Reduced pasting parameters and changes in FTIR spectrum significantly differed from each other. XRD pattern of irradiated starches showed C-type pattern with intermediate peaks of 2θ at 16.92° and 18.12°, strong peaks of 2θ at 23.05° and weak peaks of 2θ at 14.7°, displaying slight decreased in the intensity of peaks in irradiated starches. Irradiation of starches increased gelatinization temperatures and enthalpy value was measured using DSC.

  5. Effect of gamma-irradiation on the survival of Listeria monocytogenes and allergenicity of cherry tomatoes

    NASA Astrophysics Data System (ADS)

    Todoriki, Setsuko; Bari, Latiful; Kitta, Kazumi; Ohba, Mika; Ito, Yasuhiro; Tsujimoto, Yuka; Kanamori, Norihito; Yano, Erika; Moriyama, Tatsuya; Kawamura, Yukio; Kawamoto, Shinichi

    2009-07-01

    The presence of Listeria monocytogenes in fresh produce is a growing concern because of the possibility of food-borne illness. Ionizing radiation is an effective non-thermal means of eliminating pathogenic bacteria in fresh produce; however, the effect of ionizing irradiation on the allergenic properties of the host commodities remains unknown. This study aimed (i) to determine the effective dose of gamma-irradiation in eliminating L. monocytogenes on whole cherry tomatoes and (ii) to evaluate the effect of gamma-irradiation on the allergenic properties of tomato proteins. Cherry tomatoes that were inoculated with a mixture of five L. monocytogenes strains were treated with gamma-rays from a 60Co source. A 1.25 kGy dose of gamma-irradiation was found to be sufficient to eliminate L. monocytogenes on whole cherry tomatoes. The immunoblot profile of serum samples obtained from two patients with tomato allergy revealed that gamma-irradiation did not affect the allergenicity of tomato proteins for up to 7 days after irradiation when the tomatoes were stored at 20 °C. Additionally, the m-RNA levels of β-fructofuranosidase, polygalacturonase, pectin esterase, and superoxide dismutase, the main allergenic proteins in tomato, were not affected by the applied irradiation dose. Thus, this study demonstrated that a 1.25 kGy dose of gamma-irradiation effectively eliminates L. monocytogenes on cherry tomatoes without affecting the expression of allergenic proteins in the fruits.

  6. Swift Heavy Ion Irradiation Effects on NPN rf Power Transistors

    NASA Astrophysics Data System (ADS)

    Pushpa, N.; Prakash, A. P. Gnana; Gupta, S. K.; Revannasiddaiah, D.

    2011-07-01

    The dc characteristics of NPN rf power transistors were studied systematically before and after irradiation by 50 MeV Li3+ ions, 100 MeV F8+ ions and 140 MeV Si10+ ions in the dose range of 100 krad to 100 Mrad. The transistor parameters such as excess base current (ΔIB = IBpost-IBpre), dc current gain (hFE), and collector-saturation current (ICSat) were determined before and after irradiation. The base current (IB) was found to increase significantly after ion irradiation and this in turn decreases the hFE of the transistors. Further, the output characteristics of the irradiated devices exhibit the decrease in the collector current at the saturation region (ICSat) with increase of ion dose.

  7. Irradiation effects on canvas oil painting: Spectroscopic observations

    NASA Astrophysics Data System (ADS)

    Manea, Mihaela Maria; Negut, C. D.; Stanculescu, Ioana Rodica; Ponta, C. C.

    2012-10-01

    "Winter" oil painting, by Romanian contemporary artist George Alexandrescu was used as experimental model for the substantiation of gamma radiation treatment, as the best choice to stop the biological attack of paintings. In this purpose, spectroscopic and colorimetric methods were used to analyse in situ, non-destructively and non-contact, the experimental model before and after 60Co gamma irradiation. Chemical structure and colour changes were monitored by FTIR, FT-Raman and Vis reflectance spectroscopy. Negligible Infrared spectral transformations have been observed after irradiation. Furthermore, it was found that gamma irradiation did not induce any significant colour alterations. Insignificant structural and colour changes observed, recommend the use of gamma irradiation in the disinfection of oil paintings.

  8. Effect of gamma irradiation on the structure of fucoidan

    NASA Astrophysics Data System (ADS)

    Choi, Jong-il; Gu Lee, Sung; Jong Han, Se; Cho, Minho; Cheon Lee, Pyung

    2014-07-01

    The change of molecular structure of fucoidan by gamma irradiation was analyzed by spectral and chemical methods. Fucoidan samples with different molecular weights of 85, 30, 15, and 7 kDa were prepared by radiation degradation of 217 kDa fucoidan. In the molecular weight analysis, the polydispersity decreased by gamma radiation because of further degradation of higher weight molecules. Ultraviolet absorption and Fourier-transform infrared spectroscopy analyses were carried out to define the changes of the functional groups in fucoidan by gamma irradiation. Carboxyl groups and carbon double bonds increased by gamma irradiation; however, sulfate content remained unchanged. The granular fissures were observed from scanning electron microscopy in gamma-irradiated fucoidan.

  9. Effects of irradiated biodegradable polymer in endothelial cell monolayer formation

    NASA Astrophysics Data System (ADS)

    Arbeitman, Claudia R.; del Grosso, Mariela F.; Behar, Moni; García Bermúdez, Gerardo

    2013-11-01

    In this work we study cell adhesion, proliferation and cell morphology of endothelial cell cultured on poly-L-lactide acid (PLLA) modified by heavy ion irradiation. Thin films of PLLA samples were irradiated with sulfur (S) at energies of 75 MeV and gold (Au) at 18 MeV ion-beams. Ion beams were provided by the Tandar (Buenos Aires, Argentina) and Tandetron (Porto Alegre, Brazil) accelerators, respectively. The growth of a monolayer of bovine aortic endothelial cells (BAEC) onto unirradiated and irradiated surfaces has been studied by in vitro techniques in static culture. Cell viability and proliferation increased on modified substrates. But the results on unirradiated samples, indicate cell death (necrosis/apoptosis) with the consequent decrease in proliferation. We analyzed the correlation between irradiation parameters and cell metabolism and morphology.

  10. The effect of chronic low back pain on tactile suppression during back movements.

    PubMed

    Van Damme, Stefaan; Van Hulle, Lore; Danneels, Lieven; Spence, Charles; Crombez, Geert

    2014-10-01

    The aim of the present study was to examine whether tactile suppression, the phenomenon whereby tactile perception is suppressed during movement, would occur in the context of back movements. Of particular interest, it was investigated if tactile suppression in the back would be attenuated in those suffering from chronic low back pain. Individuals with chronic low back pain (N = 30) and a matched control group (N = 24) detected tactile stimuli on three possible locations (back, arm, chest) while performing a back or arm movement, or no movement. We hypothesized that the movements would induce tactile suppression, and that this effect would be largest for low-intense stimuli on the moving body part. We further hypothesized that, during back movements, tactile suppression on the back would be less pronounced in the chronic low back pain group than in the control group. The results showed the expected general tactile suppression effects. The hypothesis of back-specific attenuation of tactile suppression in the chronic low back pain group was not supported. However, back-specific tactile suppression in the chronic low back pain group was less pronounced in those who performed the back movements more slowly.

  11. Effect of heavy-ion and electron irradiation on properties of Fe-based superconductors

    NASA Astrophysics Data System (ADS)

    Konczykowski, Marcin

    2013-03-01

    The introduction of defects by particle irradiation is used to reveal the role of disorder in matter, which is unavoidable in all crystalline solids. In superconductors defects introduce flux pinning, controlling critical current, Jc; as well as pair-breaking scattering, limiting the critical temperature, Tc. To elucidate defect related properties of Fe-based superconductors (FBS) we precede in two types of irradiation: heavy ion (6GeV Pb) to create disorder in the form of amorphous tracks and low temperature electron irradiation (2.5MeV at 20K) to create point like defects. Substantial increase of irreversible magnetization and an upward shift of the irreversibility line are observed after heavy ion irradiation of all FBS investigated to date. In BaK 122 , signatures of a Bose-glass vortex state; angular dependence and variable-range hopping flux creep are revealed. Remarkably, heavy ion irradiation does not depress Tc, however, point-like disorder introduced by electron irradiation does substantially. In isovalently substituted Ba(FeAs1 - xPx) 2 and Ba(Fe1 - x Rux As) 2 crystals, Tc decreases linearly with dose. Suppression to 40 % of initial value of Tc was achieved in Ba(FeAs1 - xPx) 2 . An increase of normal state resistivity is observed and correlated to depression of Tc. Change of superconducting gap structure with disorder was determined from penetration depth measurements, λ (T) dependence, at various stages of irradiation. Linear in T variation of pristine samples, indicative of the presence of nodes in gap, turned at low irradiation dose to exponential T variation, indicative of a fully gaped state. T2 variation of λ is observed at higher doses. This behaviour is incompatible with symmetry-imposed nodes of d-wave pairing but consistent with S + / - , S + / + mechanisms. This is the first observation of the impurity-induced node lifting expected in anisotropic s-wave superconductors

  12. An experimental test of the LPM effect: Bremsstrahlung suppression at high energies

    SciTech Connect

    Klein, S.; Cavalli-Sforza, M.; Kelley, L.; Anthony, P.; Dietrich, F.; Vanbibber, K.; Becker-Szendy, R.; Gearhart, R.; Niemi, G.; Perl, M.; Rochester, L.; Bosted, P.; Cowan, R.

    1992-11-01

    We are preparing an experiment at SLAC to test the LPM (Landau-Pomeranchuk-Migda) effect. In bremsstrahlung from high energy electrons, the longitudinal momentum transferred from the nucleus is very small. Then, by the uncertainty principle, the interaction must occur over a distance much larger than the atomic scale. In the LPM effect, multiple scattering changes the electron trajectory within the interaction distance, and so suppresses the bremsstrahlung. This effect, predicted in the 1950`s, has never been quantitatively studied. For dense, high Z, targets in a 25 GeV electron beam, suppression is significant for photons below a few hundred MeV. By comparing bremsstrahlung from targets of different (Pb, U, W and C), it is possible to measure the suppression accurately. We will also study the longitudinal density effect, where very low energy photon emission is suppressed due to the dielectric effect of the medium.

  13. An experimental test of the LPM effect: Bremsstrahlung suppression at high energies

    SciTech Connect

    Klein, S.; Cavalli-Sforza, M.; Kelley, L. . Inst. for Particle Physics); Anthony, P.; Dietrich, F.; Vanbibber, K. ); Becker-Szendy, R.; Gearhart, R.; Niemi, G.; Perl, M.; Rochester, L. ); Bosted, P. (American Univ., Washington, DC (United

    1992-11-01

    We are preparing an experiment at SLAC to test the LPM (Landau-Pomeranchuk-Migda) effect. In bremsstrahlung from high energy electrons, the longitudinal momentum transferred from the nucleus is very small. Then, by the uncertainty principle, the interaction must occur over a distance much larger than the atomic scale. In the LPM effect, multiple scattering changes the electron trajectory within the interaction distance, and so suppresses the bremsstrahlung. This effect, predicted in the 1950's, has never been quantitatively studied. For dense, high Z, targets in a 25 GeV electron beam, suppression is significant for photons below a few hundred MeV. By comparing bremsstrahlung from targets of different (Pb, U, W and C), it is possible to measure the suppression accurately. We will also study the longitudinal density effect, where very low energy photon emission is suppressed due to the dielectric effect of the medium.

  14. Combined Effects of Temperature and Irradiation on Concrete Damage

    DOE PAGES

    Le Pape, Yann; Giorla, Alain; Sanahuja, Julien

    2016-01-01

    Aggregate radiation-induced volumetric expansion (RIVE) is a predominant mechanism in the formation of mechanical damage in the hardened cement paste (hcp) of irradiated concrete under fast-neutron flux (Giorla et al. 2015). Among the operating conditions difference between test reactors and light water reactors (LWRs), the difference of irradiation flux and temperature is significant. While a temperature increase is quite generally associated with a direct, or indirect (e.g., by dehydration) loss of mechanical properties (Maruyama et al. 2014), we found that it causes a partial annealing of irradiation amorphization of α-quartz, hence, reducing RIVE rate. Based on data collected by Bykovmore » et al. (1981), an incremental RIVE model coupling neutron fluence and temperature is developed. The elastic properties and coefficient of thermal expansion (CTE) of irradiated polycrystalline quartz are interpreted through analytical homogenization of experimental data on irradiated α-quartz published by Mayer and Lecomte (1960). Moreover, the proposed model, implemented in the meso-scale simulation code AMIE, is compared to experimental data obtained on ordinary concrete made of quartz/quartzite aggregate (Dubrovskii et al. 1967). Substantial discrepancy, in terms of damage and volumetric expansion developments, is found when comparing irradiation scenarios assuming constant flux and temperature, as opposed to more realistic test reactor operation conditions.« less

  15. Combined Effects of Temperature and Irradiation on Concrete Damage

    SciTech Connect

    Le Pape, Yann; Giorla, Alain; Sanahuja, Julien

    2016-01-01

    Aggregate radiation-induced volumetric expansion (RIVE) is a predominant mechanism in the formation of mechanical damage in the hardened cement paste (hcp) of irradiated concrete under fast-neutron flux (Giorla et al. 2015). Among the operating conditions difference between test reactors and light water reactors (LWRs), the difference of irradiation flux and temperature is significant. While a temperature increase is quite generally associated with a direct, or indirect (e.g., by dehydration) loss of mechanical properties (Maruyama et al. 2014), we found that it causes a partial annealing of irradiation amorphization of α-quartz, hence, reducing RIVE rate. Based on data collected by Bykov et al. (1981), an incremental RIVE model coupling neutron fluence and temperature is developed. The elastic properties and coefficient of thermal expansion (CTE) of irradiated polycrystalline quartz are interpreted through analytical homogenization of experimental data on irradiated α-quartz published by Mayer and Lecomte (1960). Moreover, the proposed model, implemented in the meso-scale simulation code AMIE, is compared to experimental data obtained on ordinary concrete made of quartz/quartzite aggregate (Dubrovskii et al. 1967). Substantial discrepancy, in terms of damage and volumetric expansion developments, is found when comparing irradiation scenarios assuming constant flux and temperature, as opposed to more realistic test reactor operation conditions.

  16. Effect of high-dose irradiation on quality characteristics of ready-to-eat chicken breast

    NASA Astrophysics Data System (ADS)

    Yun, Hyejeong; Haeng Lee, Kyung; Jung Lee, Hyun; Woon Lee, Ju; Uk Ahn, Dong; Jo, Cheorun

    2012-08-01

    High-dose (higher than 30 kGy) irradiation has been used to sterilize specific-purposed foods for safe and long-term storage. The objective of this study was to investigate the effect of high-dose irradiation on the quality characteristics of ready-to-eat chicken breast in comparison with those of the low-dose irradiation. Ready-to-eat chicken breast was manufactured, vacuum-packaged, and irradiated at 0, 5, and 40 kGy. The populations of total aerobic bacteria were 4.75 and 2.26 Log CFU/g in the samples irradiated at 0 and 5 kGy, respectively. However, no viable cells were detected in the samples irradiated at 40 kGy. On day 10, bacteria were not detected in the samples irradiated at 40 kGy but the number of bacteria in the samples irradiated at 5 kGy was increased. The pH at day 0 was higher in the samples irradiated at 40 kGy than those at 0 and 5 kGy. The 2-thiobarbituric acid reactive substance (TBARS) values of the samples were not significantly different on day 0. However, on day 10, the TBARS value was significantly higher in the samples irradiated at 40 kGy than those at 0 and 5 kGy. There was no difference in the sensory scores of the samples, except for off-flavor, which was stronger in samples irradiated at 5 and 40 kGy than control. However, no difference in off-flavor between the irradiated ones was observed. After 10 days of storage, only the samples irradiated at 40 kGy showed higher off-flavor score. SPME-GC-MS analysis revealed that 5 kGy of irradiation produced 2-methylbutanal and 3-methylbutanal, which were not present in the control, whereas 40 kGy of irradiation produced hexane, heptane, pentanal, dimethly disulfide, heptanal, and nonanal, which were not detected in the control or the samples irradiated at 5 kGy. However, the amount of compounds such as allyl sulfide and diallyl disulfide decreased significantly in the samples irradiated at 5 kGy and 40 kGy.

  17. An evaluation of the effect of microwave irradiation on bone decalcification aimed to DNA extraction.

    PubMed

    Imaizumi, Kazuhiko; Taniguchi, Kei; Ogawa, Yoshinori

    2013-09-01

    An effect of intermittent microwave irradiation on decalcification of compact bone followed by DNA extraction was verified. In order to perform quantitative analysis regarding the degree of decalcification, Cubic bone specimens were prepared from bovine metacarpal bone and micro-focus X-ray CT imaging was applied to measure precise volume of decalcified area in the cubes. Microwave irradiation was performed under strict control of temperature using commercially available experimental device which is designed for advancing tissue fixation, decalcification, and antigen-antibody reaction by intermittent microwave. The integrity of the DNA obtained from irradiated specimen was also examined by PCR analysis. The results of morphological analysis with CT imaging showed that microwave irradiation has a positive effect on decalcification though that effect is not so drastic. The results obtained from PCR analysis showed that microwave irradiation decrease amplifiable DNA, suggesting that we should be careful to use microwave for the purpose of bone DNA extraction.

  18. Relations between the physiological state of onions and an effective sprout inhibition by irradiation

    NASA Astrophysics Data System (ADS)

    Dahlhelm, H.; Matejko, C.

    The mitotic activity in shoot meristem was examined during the entire storage period of onions ( Allium cepa L.) and was compared with the growth of the inner bud of the bulbs unirradiated and after irradiation. The meaning of cell division at the shoot apex for the sprouting of onions and the effect of γ-irradiation are discussed.

  19. Study of the electron irradiation effect on the structure of treatment systems biomaterials

    NASA Astrophysics Data System (ADS)

    Yesyrev, O. V.; Kupchishin, A. I.; Abdukhairova, A. T.; Nauryzbayev, M. K.; Khodarina, N. N.; Cherednichenko, V. C.

    2017-01-01

    Experimental studies on the effects of pollution and electron irradiation on the structure of a number of treatment systems biomaterials of Sorbulak lake-storage were carried out. It was found that contamination with heavy metal and electron irradiation, respectively, affect the structure of biomaterials.

  20. An acute negative bystander effect of γ-irradiated recipients on transplanted hematopoietic stem cells.

    PubMed

    Shen, Hongmei; Yu, Hui; Liang, Paulina H; Cheng, Haizi; XuFeng, Richard; Yuan, Youzhong; Zhang, Peng; Smith, Clayton A; Cheng, Tao

    2012-04-12

    Ultimate success of hematopoietic stem cell transplantation (HSCT) depends not only on donor HSCs themselves but also on the host environment. Total body irradiation is a component in various host conditioning regimens for HSCT. It is known that ionizing radiation exerts "bystander effects" on nontargeted cells and that HSCs transplanted into irradiated recipients undergo proliferative exhaustion. However, whether irradiated recipients pose a proliferation-independent bystander effect on transplanted HSCs is unclear. In this study, we found that irradiated mouse recipients significantly impaired the long-term repopulating ability of transplanted mouse HSCs shortly (∼ 17 hours) after exposure to irradiated hosts and before the cells began to divide. There was an increase of acute cell death associated with accelerated proliferation of the bystander hematopoietic cells. This effect was marked by dramatic down-regulation of c-Kit, apparently because of elevated reactive oxygen species. Administration of an antioxidant chemical, N-acetylcysteine, or ectopically overexpressing a reactive oxygen species scavenging enzyme, catalase, improved the function of transplanted HSCs in irradiated hosts. Together, this study provides evidence for an acute negative, yet proliferation-independent, bystander effect of irradiated recipients on transplanted HSCs, thereby having implications for HSCT in both experimental and clinical scenarios in which total body irradiation is involved.

  1. Effects of gamma and electron beam irradiation on the microbial quality of steamed tofu rolls

    NASA Astrophysics Data System (ADS)

    Jia, Qian; Gao, Meixu; Li, Shurong; Wang, Zhidong

    2013-01-01

    The effectiveness of two kinds of radiation processing, gamma and electron beam (ebeam) irradiation, for the inactivation of Staphylococcus aureus, Salmonella enteritidis and Listeria innocua which were inoculated in pre-sterilised steamed tofu rolls was studied. The corresponding effects of both irradiation types on total bacterial counts (TBCs) in commercial steamed tofu rolls available in the market were also examined. The microbiological results demonstrated that gamma irradiation yielded D10 values of 0.20, 0.24 and 0.22 kGy for S. aureus, S. enteritidis and L. innocua, respectively. The respective D10 values for ebeam irradiation were 0.31, 0.35 and 0.27 kGy. Gamma and ebeam irradiation yielded D10 values of 0.48 and 0.43 kGy for total bacterial counts in commercial steamed tofu rolls, respectively. The results suggest that ebeam irradiation has similar effect on decreasing TBCs in steamed tofu rolls, and gamma irradiation is slightly more effective than ebeam irradiation in reducing the populations of pathogenic bacteria. The observed differences in D10-values between them might be due to the significant differences in dose rate applied, and radiation processing of soybean products to improve their microbial quality could be available for other sources of protein.

  2. Central nervous system effects of whole-body proton irradiation.

    PubMed

    Sweet, Tara Beth; Panda, Nirlipta; Hein, Amy M; Das, Shoshana L; Hurley, Sean D; Olschowka, John A; Williams, Jacqueline P; O'Banion, M Kerry

    2014-07-01

    Space missions beyond the protection of Earth's magnetosphere expose astronauts to an environment that contains ionizing proton radiation. The hazards that proton radiation pose to normal tissues, such as the central nervous system (CNS), are not fully understood, although it has been shown that proton radiation affects the neurogenic environment, killing neural precursors and altering behavior. To determine the time and dose-response characteristics of the CNS to whole-body proton irradiation, C57BL/6J mice were exposed to 1 GeV/n proton radiation at doses of 0-200 cGy and behavioral, physiological and immunohistochemical end points were analyzed over a range of time points (48 h-12 months) postirradiation. These experiments revealed that proton radiation exposure leads to: 1. an acute decrease in cell division within the dentate gyrus of the hippocampus, with significant differences detected at doses as low as 10 cGy; 2. a persistent effect on proliferation in the subgranular zone, at 1 month postirradiation; 3. a decrease in neurogenesis at doses as low as 50 cGy, at 3 months postirradiation; and 4. a decrease in hippocampal ICAM-1 immunoreactivity at doses as low as 10 cGy, at 1 month postirradiation. The data presented contribute to our understanding of biological responses to whole-body proton radiation and may help reduce uncertainty in the assessment of health risks to astronauts. These findings may also be relevant to clinical proton beam therapy.

  3. Noise suppressing capillary separation system

    DOEpatents

    Yeung, Edward S.; Xue, Yongjun

    1996-07-30

    A noise-suppressing capillary separation system for detecting the real-time presence or concentration of an analyte in a sample is provided. The system contains a capillary separation means through which the analyte is moved, a coherent light source that generates a beam which is split into a reference beam and a sample beam that irradiate the capillary, and a detector for detecting the reference beam and the sample beam light that transmits through the capillary. The laser beam is of a wavelength effective to be absorbed by a chromophore in the capillary. The system includes a noise suppressing system to improve performance and accuracy without signal averaging or multiple scans.

  4. Effect of Packaging and Antioxidant Combinations on Physicochemical Properties of Irradiated Restructured Chicken Rolls

    PubMed Central

    Yim, Dong-Gyun; Ahn, Dong U.

    2015-01-01

    Effects of double packaging (combinational use of aerobic and vacuum conditions) and antioxidants on physicochemical properties in irradiated restructured chicken rolls were determined. Chicken breast treated with antioxidants (none, sesamol+a-tocopherol) was used to process restructured chicken breast rolls. The sliced rolls were vacuum, aerobic, or double packaged (vacuum for 7 d then aerobic for 3 d) and electron beam irradiated at 2.5 kGy. Color, 2-thiobarbituric acid reactive substances (TBARS), oxidation reduction potentials (ORP), and volatile profiles of the samples were determined at 0 and 10 d. Irradiation made restructured chicken rolls redder (p<0.05), and the increased redness was more distinct in irradiated vacuum-packaged than irradiated aerobic or double packaged meats. TBARS values of antioxidant-treated double packaged rolls were lower than even nonirradiated vacuum-packaged meat, and those were distinct at 10 d (p<0.05). ORP and lipid oxidation values were lower in irradiated vacuum and double packaged samples than those in irradiated aerobic packaged ones at 0 d (p<0.05). Irradiation of restructured chicken rolls increased the amount of total volatiles. Considerable amounts of off-odor volatiles were reduced or not detected by double packaging and antioxidant treatment at 10 d. Therefore, the combined use of antioxidants and double packaging would be useful to reduce redness and control the oxidative quality changes of irradiated restructured chicken rolls. PMID:26761835

  5. Preserving effects of melatonin on the levels of glutathione and malondialdehyde in rats exposed to irradiation.

    PubMed

    Yildirim, O; Comoğlu, S; Yardimci, S; Akmansu, M; Bozkurt, G; Sürücü, S

    2008-03-01

    In this study we investigated whether pretreatment with melatonin was protective against the injury of the central nervous system (CNS) in rats receiving LD(50) whole body irradiation. The wistar rats were randomized into four groups: i) the control group (CG), ii) melatonin-administered group (MG; 1 mg/kg body weight), iii) irradiated group (RG; 6.75 Gy, one dose), and iv) melatonin-administered and irradiated group (MRG). Blood samples were drawn from the rats 24 h after the treatment and plasma glutathione levels were assayed. Plasma glutathione level was significantly higher in RG than CG. The melatonin pretreatment prevented GSH increase induced by irradiation. Lipid peroxidation and glutathione levels of rat cerebral cortex were determined in all groups after 24 h. Cortical malondialdehyde (MDA) was significantly higher in the RG. The melatonin pretreatment prevented cortical MDA increase induced by irradiation. Cortical GSH was significantly lower in RG than the CG. The melatonin pretreatment prevented cortical GSH decrease induced by irradiation. Tissue samples were obtained from cerebral cortex and hypothalamus which also were affected by ionizing irradiation in the CNS and were evaluated with electron microscopy. Histopathological findings showed that LD(50) whole body irradiation resulted in damage of the neuronal cells of CNS. The results obtained from this study demonstrated that pretreatment with melatonin prevented the damage that develops in CNS following irradiation. The beneficial effect of melatonin can be related to protection of the CNS from oxidative injury and preventing the decrease in the level of cortical glutathione.

  6. Antiapoptotic effect of L-carnitine on testicular irradiation in rats.

    PubMed

    Kanter, Mehmet; Topcu-Tarladacalisir, Yeter; Parlar, Sule

    2010-04-01

    We evaluated the effects of L-carnitine on apoptosis of germ cells in the rat testis following irradiation. Male Wistar rats were divided into three groups. Control group received sham irradiation plus physiological saline. Radiotherapy group received scrotal gamma-irradiation of 10 Gy as a single dose plus physiological saline. Radiotherapy + L-carnitine group received scrotal irradiation plus 200 mg/kg intraperitoneally L-carnitine. Twenty-four hours post-irradiation, the rats were sacrificed and testes were harvested. Testicular damage was examined by light and electron microscopy, and germ cell apoptosis was determined by terminal deoxynucleotidyltransferase-mediated deoxyuridine triphosphate in situ nick end-labeling (TUNEL) technique. Morphologically, examination of irradiated testis revealed presence of disorganization and desquamation of germinal cells and the reduction in sperm count in seminiferous tubule lumen. Under electron microscopy, the morphological signs of apoptosis were frequently detected in spermatogonia. Apoptotic spermatogonia showed the marginal condensation of chromatin onto the nuclear lamina, nucleus and cytoplasm shrinkage and still functioning cell organelles. TUNEL-positive cells were significantly more numerous in irradiated rats than in control rats. L-carnitine treatment significantly attenuated the radiation-induced morphological changes and germ cell apoptosis in the irradiated rat testis. In conclusion, these results suggested that L-carnitine supplementation during the radiotherapy may be beneficial for spermatogenesis following testicular irradiation by decreasing germ cell apoptosis.

  7. Effects of search efficiency on surround suppression during visual selection in frontal eye field.

    PubMed

    Schall, Jeffrey D; Sato, Takashi R; Thompson, Kirk G; Vaughn, Amanda A; Juan, Chi-Hung

    2004-06-01

    Previous research has shown that visually responsive neurons in the frontal eye field of macaque monkeys select the target for a saccade during efficient, pop-out visual search through suppression of the representation of the nontarget distractors. For a fraction of these neurons, the magnitude of this distractor suppression varied with the proximity of the target to the receptive field, exhibiting more suppression of the distractor representation when the target was nearby than when the target was distant. The purpose of this study was to determine whether the variation of distractor suppression related to target proximity varied with target-distractor feature similarity. The effect of target proximity on distractor suppression did not vary with target-distractor similarity and therefore may be an endogenous property of the selection process.

  8. Performance suppression from control procedures is not the basis of the Mozart effect.

    PubMed

    Rideout, B E

    1999-12-01

    The suggestion by others that previous replications of the Mozart effect in this laboratory are due to suppression of arousal from a relaxation control procedure is inconsistent with our published data.

  9. EFFECTS OF GAMMA IRRADIATION ON EPDM ELASTOMERS (REVISION 1)

    SciTech Connect

    Clark, E.

    2013-09-13

    Two formulations of EPDM elastomer, one substituting a UV stabilizer for the normal antioxidant in this polymer, and the other the normal formulation, were synthesized and samples of each were exposed to gamma irradiation in initially pure deuterium gas to compare their radiation stability. Stainless steel containers having rupture disks were designed for this task. After 130 MRad dose of cobalt-60 radiation in the SRNL Gamma Irradiation Facility, a significant amount of gas was created by radiolysis; however the composition indicated by mass spectroscopy indicated an unexpected increase in the total amount deuterium in both formulations. The irradiated samples retained their ductility in a bend test. No change of sample weight, dimensions, or density was observed. No change of the glass transition temperature as measured by dynamic mechanical analysis was observed, and most of the other dynamic mechanical properties remained unchanged. There appeared to be an increase in the storage modulus of the irradiated samples containing the UV stabilizer above the glass transition, which may indicate hardening of the material by radiation damage. Revision 1 adds a comparison with results of a study of tritium exposed EPDM. The amount of gas produced by the gamma irradiation was found to be equivalent to about 280 days exposure to initially pure tritium gas at one atmosphere. The glass transition temperature of the tritium exposed EPDM rose about 10°C. over 280 days, while no glass transition temperature change was observed for gamma irradiated EPDM. This means that gamma irradiation in deuterium cannot be used as a surrogate for tritium exposure.

  10. Effect of Gamma Irradiation on Structural and Biological Properties of a PLGA-PEG-Hydroxyapatite Composite

    PubMed Central

    Shahabi, Sima; Najafi, Farhood; Majdabadi, Abbas; Hooshmand, Tabassom; Haghbin Nazarpak, Masoumeh; Karimi, Batool

    2014-01-01

    Gamma irradiation is able to affect various structural and biological properties of biomaterials In this study, a composite of Hap/PLGA-PEG and their ingredients were submitted to gamma irradiation doses of 25 and 50 KGy. Various properties such as molecular weight (GPC), thermal behavior (DSC), wettability (contact angle), cell viability (MTT assay), and alkaline phosphatase activity were studied for the composites and each of their ingredients. The results showed a decrease in molecular weight of copolymer with no change in the glass transition and melting temperatures after gamma irradiation. In general gamma irradiation can increase the activation energy ΔH of the composites and their ingredients. While gamma irradiation had no effect on the wettability of copolymer samples, there was a significant decrease in contact angle of hydroxyapatite and composites with increase in gamma irradiation dose. This study showed an increase in biocompatibility of hydroxyapatite with gamma irradiation with no significant effect on cell viability in copolymer and composite samples. In spite of the fact that no change occurred in alkaline phosphatase activity of composite samples, results indicated a decrease in alkaline phosphatase activity in irradiated hydroxyapatites. These effects on the properties of PLGA-PEG-hydroxyapatite can enhance the composite application as a biomaterial. PMID:25574485

  11. On the effect of X-ray irradiation on the deformation and fracture behavior of human cortical bone.

    PubMed

    Barth, Holly D; Launey, Maximilien E; Macdowell, Alastair A; Ager, Joel W; Ritchie, Robert O

    2010-06-01

    In situ mechanical testing coupled with imaging using high-energy synchrotron X-ray diffraction or tomography is gaining in popularity as a technique to investigate micrometer and even sub-micrometer deformation and fracture mechanisms in mineralized tissues, such as bone and teeth. However, the role of the irradiation in affecting the nature and properties of the tissue is not always taken into account. Accordingly, we examine here the effect of X-ray synchrotron-source irradiation on the mechanistic aspects of deformation and fracture in human cortical bone. Specifically, the strength, ductility and fracture resistance (both work-of-fracture and resistance-curve fracture toughness) of human femoral bone in the transverse (breaking) orientation were evaluated following exposures to 0.05, 70, 210 and 630 kGrays (kGy) irradiation. Our results show that the radiation typically used in tomography imaging can have a major and deleterious impact on the strength, post-yield behavior and fracture toughness of cortical bone, with the severity of the effect progressively increasing with higher doses of radiation. Plasticity was essentially suppressed after as little as 70 kGy of radiation; the fracture toughness was decreased by a factor of five after 210 kGy of radiation. Mechanistically, the irradiation was found to alter the salient toughening mechanisms, manifest by the progressive elimination of the bone's capacity for plastic deformation which restricts the intrinsic toughening from the formation "plastic zones" around crack-like defects. Deep-ultraviolet Raman spectroscopy indicated that this behavior could be related to degradation in the collagen integrity.

  12. On the effect of x-ray irradiation on the deformation and fracture behavior of human cortical bone

    SciTech Connect

    Barth, Holly D.; Launey, Maximilien E.; McDowell, Alastair A.; Ager III, Joel W.; Ritchie, Robert O.

    2010-01-10

    In situ mechanical testing coupled with imaging using high-energy synchrotron x-ray diffraction or tomography imaging is gaining in popularity as a technique to investigate micrometer and even sub-micrometer deformation and fracture mechanisms in mineralized tissues, such as bone and teeth. However, the role of the irradiation in affecting the nature and properties of the tissue is not always taken into account. Accordingly, we examine here the effect of x-ray synchrotron-source irradiation on the mechanistic aspects of deformation and fracture in human cortical bone. Specifically, the strength, ductility and fracture resistance (both work-of-fracture and resistance-curve fracture toughness) of human femoral bone in the transverse (breaking) orientation were evaluated following exposures to 0.05, 70, 210 and 630 kGy irradiation. Our results show that the radiation typically used in tomography imaging can have a major and deleterious impact on the strength, post-yield behavior and fracture toughness of cortical bone, with the severity of the effect progressively increasing with higher doses of radiation. Plasticity was essentially suppressed after as little as 70 kGy of radiation; the fracture toughness was decreased by a factor of five after 210 kGy of radiation. Mechanistically, the irradiation was found to alter the salient toughening mechanisms, manifest by the progressive elimination of the bone's capacity for plastic deformation which restricts the intrinsic toughening from the formation 'plastic zones' around crack-like defects. Deep-ultraviolet Raman spectroscopy indicated that this behavior could be related to degradation in the collagen integrity.

  13. Effect of irradiation for recovery of organic wastes from potato starch wastewater with chitosan

    NASA Astrophysics Data System (ADS)

    Kume, Tamikazu; Takehisa, Masaaki

    The irradiation effect on recovery of organic substances from potato starch wastewater with aid of chitosan and disinfection were investigated for recycling the organic wastes into animal feeds. Chitosan was effective as a coagulant for suspended solids in the wastewater and the optimum concentration was 8-10 x 10 -30/0. The irradiation promotes the coagulation of the organic wastes. Especially, the coagulation of the proteins with chitosan increased by irradiation since the soluble proteins became insoluble by irradiation. The numbers of total aerobic bacteria in the wastewater and in the coagulum with chitosan were 8.0 x 10 7 and 3.5 x 10 8counts/ ml, respectively, and decreased to 11 and 45 counts/ml by 1.0 Mrad irradiation.

  14. Effect of electron irradiation on the gel properties of Collichthys lucidus surimi

    NASA Astrophysics Data System (ADS)

    Deng, Siyao; Lv, Liangyu; Yang, Wenge; Xu, Dalun; Lou, Qiaoming; Zhang, Jinjie

    2017-01-01

    This study evaluated the effect of electron irradiation on the gel properties of Collichthys lucidus surimi. The results showed that irradiation decreased the trichloroacetic acid-soluble peptide content of the surimi gel. At 5 kGy, a more compact and ordered gel network structure was achieved, resulting in a higher gel strength, whiteness, and water-holding capacity than non-irradiated surimi gel. During heat-induced formation of the gel, the α-helix content decreased, whilst the β-sheet and β-turn content increased. Irradiation treatments also decreased the α-helix content and increased β-sheet content, and this transformation is beneficial for the protein denaturation and gel formation. Collectively, the results suggest that electron irradiation, at an optimal dose of 5 kGy, could be an effective method for application in the surimi manufacturing industry

  15. Effect of heat treatment and irradiation temperature on impact behavior of irradiated reduced-activation ferritic steels

    SciTech Connect

    Klueh, R.L.; Alexander, D.J.

    1998-03-01

    Charpy tests were conducted on eight normalized-and-tempered reduced-activation ferritic steels irradiated in two different normalized conditions. Irradiation was conducted in the Fast Flux Test Facility at 393 C to {approx}14 dpa on steels with 2.25, 5, 9, and 12% Cr (0.1% C) with varying amounts of W, V, and Ta. The different normalization treatments involved changing the cooling rate after austenitization. The faster cooling rate produced 100% bainite in the 2.25 Cr steels, compared to duplex structures of bainite and polygonal ferrite for the slower cooling rate. For both cooling rates, martensite formed in the 5 and 9% Cr steels, and martensite with {approx}25% {delta}-ferrite formed in the 12% Cr steel. Irradiation caused an increase in the ductile-brittle transition temperature (DBTT) and a decrease in the upper-shelf energy. The difference in microstructure in the low-chromium steels due to the different heat treatments had little effect on properties. For the high-chromium martensitic steels, only the 5 Cr steel was affected by heat treatment. When the results at 393 C were compared with previous results at 365 C, all but a 5 Cr and a 9 Cr steel showed the expected decrease in the shift in DBTT with increasing temperature.

  16. Effect of gamma irradiation on commercial eggs experimentally inoculated with Salmonella enteritidis

    NASA Astrophysics Data System (ADS)

    Tellez, I. G.; Trejo, R. M.; Sanchez, R. E.; Ceniceros, R. M.; Luna, Q. P.; Zazua, P.; Hargis, B. M.

    1995-02-01

    Using intact, fresh shell eggs, inoculated with 10 8 colony-forming units (cfu) of S. enteritidis, the effect of three doses of gamma irradiation on bacteriologic population and physical characteristics (Haugh units and yolk color) of the eggs was determinated. Penetration test area was picked at random just off the air cell of each egg. Aluminum cylinders were attached to the egg surface with a rim of molten paraffin, and 10 8S. enteritidis was then applied to inoculate the egg. Eggs were then irradiated within 2 hours using a Cobalt-60 gamma source at either 1, 2, or 3 kGy. A second set of inoculated, non-irradiated was used as controls. Following irradiation, eggs were maintained at 4°C for 42 hours prior culture. Irradiation with 1 kGy resulted in a significant (P < .05), 3.9 log reduction in detectable S. enteritidis in the shell and a higly significant (P < .025) 95% reduction in detectable S. enteritidis in the internal shell membranes. Irradiation of eggs with either 2 or 3 kGy reduced bacterial contamination to non-detectable levels in both the shell and internal membranes. However, irradiation at either 1, 2 or 3 kGy resulted in a significant (P <- .05) decrease (approximately 50%) in Haugh units. Additionally, irradiation of intact shell eggs at 2 or 3 Kgy significantly (P ≤ .05) reduced yolk color regardless of the level of irradiation exposure implemented. This data indicates that gamma irradiation of intact raw eggs is effective in reducing (1 kGy) or eliminating (2 or more kGy) S. enteritidis contamination. However, each of the levels of irradiation used in the present experiments caused marked reduction of selected measures of egg quality.

  17. The effect of red light irradiation on spermatozoa DNA

    NASA Astrophysics Data System (ADS)

    Chow, Kay W.; Preece, Daryl; Gomez-Godinez, Veronica; Berns, Michael W.

    2016-09-01

    A key goal in the conservation of endangered species is to increase successful reproduction. In cases where traditional methods of in vitro fertilization are unsuccessful, new methods of assisted reproduction are needed. One option is selective fertilization via optically trapped sperm. A more passive option is red light irradiation. Red light irradiation has been shown to increase sperm motility, thus increasing fertilizing potential. However, there is some concern that exposure to laser irradiation induces the production of oxidative species in cells, which can be damaging to DNA. In order to test the safety of irradiating sperm, sperm samples were exposed to 633 nm laser light and their DNA were tested for oxidative damage. Using fluorescence microscopy, antibody staining, and ELISA to detect oxidative DNA damage, it was concluded that red light irradiation does not pose a safety risk to sperm DNA. The use of red light on sperm has potential in both animal conservation and human reproduction techniques. This method can also be used in conjunction with optical trapping for viable sperm selection.

  18. A role for chloride in the suppressive effect of acetylcholine on afferent vestibular activity.

    PubMed

    Pantoja, A M; Holt, J C; Guth, P S

    1997-10-01

    Afferents of the frog semicircular canal (SCC) respond to acetylcholine (ACh) application (0.3-1.0 mM) with a facilitation of their activity while frog saccular afferents respond with suppression (Guth et al., 1994). All recordings are of resting (i.e., non-stimulated) multiunit activity as previously reported (Guth et al., 1994). Substitution of 80% of external chloride (Cl-) by large, poorly permeant anions of different structures (isethionate, methanesulfonate, methylsulfate, and gluconate) reduced the suppressive effect of ACh in the frog saccular afferents. This substitution did not affect the facilitatory response of SCC afferents to ACh. Chloride channel blockers were also used to test further whether Cl- is involved in the ACh suppressive effect. These included: niflumic and flufenamic acids, picrotoxin, 5-nitro-2-(-3-phenylpropylamino)benzoic acid (NPPB), and 4,4'-dinitrostilbene-2,2'-disulfonic acid (DNDS). As with the Cl- substitutions, all of these agents reduced the suppressive response to ACh in the saccule, but not the facilitatory response seen in the SCC. The suppressive effect of ACh on saccular afferents is considered to be due to activation of a nicotinic-like receptor (Guth et al., 1994; Guth and Norris, 1996). Taking into account the effects of both Cl- substitutions and Cl- channel blockers, we conclude that changes in Cl- availability influence the suppressive effect of ACh and that therefore Cl- may be involved in this effect.

  19. Study of gamma irradiation effect on commercial TiO2 photocatalyst.

    PubMed

    Bello Lamo, M P; Williams, P; Reece, P; Lumpkin, G R; Sheppard, L R

    2014-07-01

    The aim of this work is to understand the effect of gamma irradiation on commercial TiO2 photocatalyst for water treatment applications. Previous studies concluded that gamma-irradiation is able to modify the electronic properties of TiO2 based photocatalysts and consequently their photocatalytic performance. However, there are some discrepancies in the literature where on one hand a significant enhancement of the material properties is reported and on the other hand only a weak effect is observed. In this study a surface effect on TiO2 is confirmed by using low and medium gamma irradiation doses.

  20. Effects of microwave power and microwave irradiation time on pretreatment efficiency and characteristics of corn stover using combination of steam explosion and microwave irradiation (SE-MI) pretreatment.

    PubMed

    Pang, Feng; Xue, Shulin; Yu, Shengshuan; Zhang, Chao; Li, Bing; Kang, Yong

    2012-08-01

    The effects of microwave power and microwave irradiation time on pretreatment efficiency and characteristics of corn stover were investigated based on a new process named combination of steam explosion and microwave irradiation (SE-MI) pretreatment. Results showed that with microwave power and microwave irradiation time increasing, glucose and xylose that released into hydrolyzate, as well as enzymatic hydrolysis yields and sugar yields of glucose and xylose were all slightly increased after SE-MI pretreatment. The maximum sugar yield was 72.1 g per 100 g glucose and xylose in feedstock, achieved at 540 W microwave power and 5 min microwave irradiation time. XRD analysis showed that the crystallinity of biomass was 15.6-19.9% lower for SE-MI pretreatment with microwave effect than that without microwave effect. However, low microwave power and short microwave irradiation time were favorable for SE-MI pretreatment considering energy consumption.

  1. The Effect of Lycopene Preexposure on UV-B-Irradiated Human Keratinocytes

    PubMed Central

    Ascenso, Andreia; Pedrosa, Tiago; Pinho, Sónia; Pinho, Francisco; de Oliveira, José Miguel P. Ferreira; Cabral Marques, Helena; Oliveira, Helena; Simões, Sandra; Santos, Conceição

    2016-01-01

    Lycopene has been reported as the antioxidant most quickly depleted in skin upon UV irradiation, and thus it might play a protective role. Our goal was to investigate the effects of preexposure to lycopene on UV-B-irradiated skin cells. Cells were exposed for 24 h to 10 M lycopene, and subsequently irradiated and left to recover for another 24 h period. Thereafter, several parameters were analyzed by FCM and RT-PCR: genotoxicity/clastogenicity by assessing the cell cycle distribution; apoptosis by performing the Annexin-V assay and analyzing gene expression of apoptosis biomarkers; and oxidative stress by ROS quantification. Lycopene did not significantly affect the profile of apoptotic, necrotic and viable cells in nonirradiated cells neither showed cytostatic effects. However, irradiated cells previously treated with lycopene showed an increase in both dead and viable subpopulations compared to nonexposed irradiated cells. In irradiated cells, lycopene preexposure resulted in overexpression of BAX gene compared to nonexposed irradiated cells. This was accompanied by a cell cycle delay at S-phase transition and consequent decrease of cells in G0/G1 phase. Thus, lycopene seems to play a corrective role in irradiated cells depending on the level of photodamage. Thus, our findings may have implications for the management of skin cancer. PMID:26664697

  2. Hepatoprotective effects of gamma-irradiated caraway essential oils in experimental sepsis.

    PubMed

    Fatemi, F; Allameh, A; Khalafi, H; Ashrafihelan, J

    2010-02-01

    Irradiation is an important method of processing herbal drugs, while our understanding of the effects of gamma-irradiation on pharmacological properties of seed products such as caraway essential oils is however still very limited. In this study, caraway seeds were irradiated at dose levels of 0, 10 and 25kGy. After extracting the essential oils, the effects of fresh and gamma-irradiated caraway oils (100mg/kg b.w) on preventing septic-related oxidative liver injury induced by cecal ligation and puncture (CLP) model were investigated by measuring oxidative stress parameters in the liver. CLP operation caused a marked increase in myeloperoxidase (MPO) activity which was readily reversed in rats treated with fresh and irradiated caraway oils. Likewise, thiobarbituric acid reactive substances (TBARS) level in the liver was compensated in rats treated with the fresh and irradiated caraway oils. Moreover, liver GSH which was initially depleted due to CLP was recovered by essential oil treatments. The protective role of oils was further confirmed by showing that liver function tests (ALT/AST) as well as histopathological changes following CLP operation were recovered in rats treated with oils from either fresh or irradiated caraway seeds. These data may suggest that gamma-irradiation to caraway seeds at 10 and 25kGy has no influence on the antioxidative properties of caraway essential oils.

  3. Effect of defect imbalance on void swelling distributions produced in pure iron irradiated with 3.5 MeV self-ions

    DOE PAGES

    Shao, Lin; Wei, C. -C.; Gigax, J.; ...

    2014-06-10

    Ion irradiation has been widely used to simulate radiation damage induced by neutrons. However, there are a number of features of ion-induced damage that differ from neutron-induced damage, and these differences require investigation before behavior arising from neutron bombardment can be confidently predicted from ion data. In this study 3.5 MeV self-ion irradiation of pure iron was used to study the influence on void swelling of the depth-dependent defect imbalance between vacancies and interstitials that arises from various surface effects, forward scattering of displaced atoms, and especially the injected interstitial effect. The depth dependence of void swelling was observed notmore » to follow the behavior anticipated from the depth dependence of the damage rate. Void nucleation and growth develop first in the lower-dose, near-surface region, and then, during continued irradiation, move to progressively deeper and higher-damage depths. This indicates a strong initial suppression of void nucleation in the peak damage region that continued irradiation eventually overcomes. This phenomenon is shown by the Boltzmann transport equation method to be due to depth-dependent defect imbalances created under ion irradiation. These findings thus demonstrate that void swelling does not depend solely on the local dose level and that this sensitivity of swelling to depth must be considered in extracting and interpreting ion-induced swelling data.« less

  4. Effect of defect imbalance on void swelling distributions produced in pure iron irradiated with 3.5 MeV self-ions

    SciTech Connect

    Shao, Lin; Wei, C. -C.; Gigax, J.; Aitkaliyeva, A.; Chen, D.; Sencer, B. H.; Garner, F. A.

    2014-06-10

    Ion irradiation has been widely used to simulate radiation damage induced by neutrons. However, there are a number of features of ion-induced damage that differ from neutron-induced damage, and these differences require investigation before behavior arising from neutron bombardment can be confidently predicted from ion data. In this study 3.5 MeV self-ion irradiation of pure iron was used to study the influence on void swelling of the depth-dependent defect imbalance between vacancies and interstitials that arises from various surface effects, forward scattering of displaced atoms, and especially the injected interstitial effect. The depth dependence of void swelling was observed not to follow the behavior anticipated from the depth dependence of the damage rate. Void nucleation and growth develop first in the lower-dose, near-surface region, and then, during continued irradiation, move to progressively deeper and higher-damage depths. This indicates a strong initial suppression of void nucleation in the peak damage region that continued irradiation eventually overcomes. This phenomenon is shown by the Boltzmann transport equation method to be due to depth-dependent defect imbalances created under ion irradiation. These findings thus demonstrate that void swelling does not depend solely on the local dose level and that this sensitivity of swelling to depth must be considered in extracting and interpreting ion-induced swelling data.

  5. An effective noise-suppression technique for surface microseismic data

    USGS Publications Warehouse

    Forghani-Arani, Farnoush; Willis, Mark; Haines, Seth S.; Batzle, Mike; Behura, Jyoti; Davidson, Michael

    2013-01-01

    The presence of strong surface-wave noise in surface microseismic data may decrease the utility of these data. We implement a technique, based on the distinct characteristics that microseismic signal and noise show in the τ‐p domain, to suppress surface-wave noise in microseismic data. Because most microseismic source mechanisms are deviatoric, preprocessing is necessary to correct for the nonuniform radiation pattern prior to transforming the data to the τ‐p domain. We employ a scanning approach, similar to semblance analysis, to test all possible double-couple orientations to determine an estimated orientation that best accounts for the polarity pattern of any microseismic events. We then correct the polarity of the data traces according to this pattern, prior to conducting signal-noise separation in the τ‐p domain. We apply our noise-suppression technique to two surface passive-seismic data sets from different acquisition surveys. The first data set includes a synthetic microseismic event added to field passive noise recorded by an areal receiver array distributed over a Barnett Formation reservoir undergoing hydraulic fracturing. The second data set is field microseismic data recorded by receivers arranged in a star-shaped array, over a Bakken Shale reservoir during a hydraulic-fracturing process. Our technique significantly improves the signal-to-noise ratios of the microseismic events and preserves the waveforms at the individual traces. We illustrate that the enhancement in signal-to-noise ratio also results in improved imaging of the microseismic hypocenter.

  6. Effect of cryogenic irradiation on NERVA structural alloys

    NASA Technical Reports Server (NTRS)

    Dixon, C. E.; Davidson, M. J.; Funk, C. W.

    1972-01-01

    Several alloys (Hastelloy X, AISI 347, A-286 bolts, Inconel 718, Al 7039-T63 and Ti-5Al-2.5Sn ELI) were irradiated in liquid nitrogen (140 R) to neutron fluences between 10 to the 17th power and 10 to the 19th power nvt (E greater than 1.0 Mev). After irradiation, tensile properties were obtained in liquid nitrogen without permitting any warmup except for some specimens which were annealed at 540 R. The usual trend of radiation damage typical for materials irradiated at and above room temperature was observed, such as an increase in strength and decrease in ductility. However, the damage at 140 R was greater because this temperature prevented the annealing of radiation-induced defects which occurs above 140 R.

  7. Effect of laser irradiation on neutrophils metabolism in stress

    NASA Astrophysics Data System (ADS)

    Brill, Gregory E.; Grigoriev, Sergei N.; Romanova, Tatyana P.; Petrisheva, Svetlana G.

    1994-02-01

    In experiments on male mice of CBA line the alteration of neutrophils cytochemical profile in peripheral blood He-Ne laser irradiation in vitro (4 mW/cm2, 15 min) and modification of metabolic disturbances in polymorphonuclear leucocytes in stress by laser radiation were studied. It was found that direct laser irradiation of blood results in the decrease of glycogen and lipids content, the increase of ATP-ase, succinate dehydrogenase and myeloperoxidase activity, rise of lysosomal cationic proteins level, and membrane oxidase systems of neutrophils stimulation. In short-term immobilization stress conditions transcutaneous laser irradiation in vivo (19 mW/cm2, 15 min) prevents the development of stress induced changes of metabolism and function of neutrophils.

  8. Effects of gamma and electron beam irradiation on the properties of calendered cord fabrics

    NASA Astrophysics Data System (ADS)

    Aytaç, Ayşe; Deniz, Veli; Şen, Murat; Hegazy, El-Sayed; Güven, Olgun

    2010-03-01

    The effects of gamma and e-beam irradiation on mechanical and structural properties of nylon 66 (Ny 66), nylon 6 (Ny 6) and poly(ethylene terephthalate) (PET) fabrics used in tyres were investigated. The untreated (greige), treated cords and calendered fabrics were irradiated at different doses. It is found that the effects of high energy irradiation on greige, treated cords and calendered fabrics are similar. No protective effect of compounds used in calendering was observed against radiation-induced oxidative degradation. The deterioration effect of gamma irradiation on mechanical properties is much higher than that of e-beam irradiation for all types of samples. Limiting viscosity numbers of both gamma and e-beam irradiated nylon 6 and nylon 66 cords were found to decrease with increasing dose. It is concluded that PET calendered fabric has higher resistance to ionizing radiation. Ny 6 and Ny 66 calendered fabrics are more sensitive even at low doses. Therefore, the effects of high energy irradiation on tyre cords have to be taken into consideration during tyre design reinforced with particularly Ny fabrics if pre-vulcanization with high energy radiation is to be applied.

  9. Human umbilical cord blood-derived stromal cells, a new resource in the suppression of acute graft-versus-host disease in haploidentical stem cell transplantation in sublethally irradiated mice.

    PubMed

    Zhang, Cheng; Chen, Xing-Hua; Zhang, Xi; Gao, Lei; Kong, Pei-Yan; Peng, Xian-gui; Liang, Xue; Gao, Li; Gong, Yi; Wang, Qing-Yu

    2011-04-15

    Human umbilical cord blood-derived stromal cells (hUCBDSCs), a novel population isolated from CD34(+) cells by our laboratory, exerted an immunosuppressive effect on xenogenic T cells. This study aimed to investigate whether hUCBDSCs play a critical role in the suppression of acute graft-versus-host disease (aGVHD). The hUCBDSCs were co-cultured with splenocytes (SPCs) of donor C57BL/6 mice. The aGVHD in the recipient (B6×BALB/c) F1 mice was induced by the infusion of bone marrow cells and SPCs from donor mice following sublethal irradiation. The shift in vivo for hUCBDSCs was detected. The proliferation and cell cycle of SPCs were tested by cell counting kit-8 and flow cytometry, respectively. The expression of CD49b natural killer (NK) cells and CD3 T cells was detected by flow cytometry in co-culture and post-transplantation. IL-4, and IFN-γ were detected by ELISA in the serum of co-culture and post-transplantation. The survival time, body weight, clinical score, and histopathological score were recorded for mice post-transplantation. The hUCBDSCs promoted the proliferation of SPCs and significantly increased the ratio of the S and G(2)/M phase (p < 0.05). The hUCBDSCs significantly increased the expression of CD49b NK cells and IL-4 protein and decreased the expression of CD3 T cells and IFN-γ protein both in vitro and in vivo. The survival time of mice with co-transplantation of hUCBDSCs was significantly prolonged, and decreased clinical and histopathological scores were also observed. The hUCBDSCs were continually detected in the target organs of GVHD. These results suggest that hUCBDSCs possess the capability of suppressing aGVHD, possibly via their influence on CD3 T cells, NK cells, and cytokines.

  10. Suppression subtractive hybridization identifies genes induced in response to UV-B irradiation in apple skin: isolation of a putative UDP-glucose 4-epimerase.

    PubMed

    Ban, Yusuke; Honda, Chikako; Bessho, Hideo; Pang, Xiao-Ming; Moriguchi, Takaya

    2007-01-01

    Suppression subtractive hybridization (SSH) successfully identified 11 cDNAs in apple skin with highly induced expression as a result of ultraviolet (UV)-B irradiation. Apart from three putative flavonoid biosynthetic genes, chalcone synthase (CHS; A5C), flavanone-3-hydroxylase (F3H; B5F), and flavonol synthase (FLS; D1F), five clones (A1H, A10E, B11G, D5F, and D11H) were induced by low temperature (17 degrees C) as well, which is also known to induce anthocyanin accumulation in apple skin. Moreover, four clones (A1H, A10E, B11G, and D11H), showing higher expression levels in the skin, accumulated higher anthocyanin concentrations than their counterparts. Of the four clones, only A10E, a putative UDP-glucose 4-epimerase (UGE), was deemed to play an important role in anthocyanin accumulation in apple skin based on the facts that: (i) its transcription level was higher in the deep red cultivar, 'Jonathan', than in the pale red cultivar, 'Tsugaru'; and (ii) it could reversibly catalyse UDP-glucose to UDP-galactose, and the latter molecule is a major sugar donor for cyanidin-glycoside in apple. Therefore, the full-length cDNA of A10E was isolated by rapid amplification of cDNA ends (RACE) and designated as MdUGE1. Further analysis demonstrated that UGE enzymatic activity was positively correlated with anthocyanin accumulation in apple skin. Thus, MdUGE1 isolated by SSH could play an important role in anthocyanin biosynthesis in apple skin in concert with other flavonoid biosynthetic genes.

  11. Molecular dynamics simulation of C/Si ratio effect on the irradiation swelling of β-SiC

    NASA Astrophysics Data System (ADS)

    Li, Yingying; Xiao, Wei; Li, Huailin

    2016-11-01

    The C/Si atom ratio effect on the irradiation swelling of β-SiC is studied using molecular dynamics (MD) simulations. The irradiation swelling decreases with the increase of C/Si ratio under the same irradiation conditions. The carbon cluster is the key issue for the irradiation swelling of non-stoichiometric SiC. The carbon cluster size increases with the increase of C/Si ratio and the number of cluster decreases with the increase of C/Si ratio after irradiation process. An analytical model is established to describe the C/Si ratio effect on irradiation swelling and it fits the MD data well.

  12. Effect of microplasma irradiation on skin barrier function

    NASA Astrophysics Data System (ADS)

    Shimizu, Kazuo; Tran, An N.; Blajan, Marius

    2016-07-01

    In this paper, we introduce the feasibility of atmospheric-pressure argon microplasma irradiation (AAMI) to promote percutaneous absorption. A hairless Yucatan micropig skin was used for this ex vivo study. After AAMI, the disturbance in the stratum corneum (SC) lipids was observed using attenuated total reflectance-Fourier transform infrared spectroscopy. Also, an increase in transepidermal water loss and no physical damage on pig skins were confirmed by microscopic observation. These results of AAMI were compared with those of a plasma jet irradiation (PJI) and a tape stripping test (TST) leading to the conclusion that AAMI reduces the barrier function of the skin and could also enhance the transdermal absorption of drugs.

  13. Impact of irradiation effects on design solutions for ITER diagnostics

    NASA Astrophysics Data System (ADS)

    Costley, A.; deKock, L.; Walker, C.; Janeschitz, G.; Yamamoto, S.; Shikama, T.; Belyakov, V.; Farnum, E.; Hodgson, E.; Nishitani, T.; Orlinski, D.; Zinkle, S.; Kasai, S.; Stott, P.; Young, K.; Zaveriaev, V.

    2000-12-01

    An overview of the results of the irradiation tests on diagnostic components under the ITER technology R&D tasks and the solutions for the present diagnostic design are given in the light of these results. A comprehensive irradiation database of diagnostic components has been accumulated and permits conclusions to be drawn on the application of these components in ITER. Under the ITER technology R&D tasks, not only has work been shared among four home teams, but also several bilateral collaborations and round-robin experiments have been performed to enhance the R&D activities.

  14. Effect of abdominal irradiation on growth in boys treated for a Wilms' tumor

    SciTech Connect

    Wallace, W.H.; Shalet, S.M.; Morris-Jones, P.H.; Swindell, R.; Gattamaneni, H.R. )

    1990-01-01

    To study the effect of abdominal irradiation on spinal growth in childhood we have measured final height, sitting height, and leg length in 30 male survivors of a Wilms' tumor. Twenty-one patients received whole abdominal irradiation by either megavoltage therapy (MV: n = 11) or orthovoltage therapy (OV: n = 10); the remainder received flank irradiation. To examine the effect of the adolescent growth spurt on the irradiated spine we have followed prospectively seven patients who received whole abdominal irradiation and nine patients who received flank irradiation through puberty. Compared to a normal population there is a modest reduction in median final standing height SDS (H.SDS: -1.15) accompanied by a marked reduction in median final sitting height SDS (S.HT SDS: -2.41) with no apparent effect on median subischial leg length SDS (SILL.SDS: 0.04). This reduction in spinal growth is reflected by a strongly positive disproportion score (DPS; (SILL SDS-S.HT SDS) + 2.81). The incidence of scoliosis after abdominal irradiation has been low (10%). During puberty there is a significant fall in median sitting height SDS after both whole abdominal (median fall: -0.9, P = 0.02) and flank irradiation (median fall: -1.85, P = 0.01), and this is reflected in a significant increase in disproportion (DPS: whole abdominal; median rise +1.4, P = 0.02: flank, median rise +1.34, P = 0.01). After MV irradiation there is a significant correlation between the degree of disproportion and the age at treatment (P less than 0.0005). The younger the patient is at treatment the more severe is the restriction on spinal growth and the shorter and more disproportionate they become as an adult. The estimated eventual loss in potential height from abdominal irradiation at the age of one is 10 cm and at five years is 7 cm.

  15. Liver irradiation causes distal bystander effects in the rat brain and affects animal behaviour.

    PubMed

    Kovalchuk, Anna; Mychasiuk, Richelle; Muhammad, Arif; Hossain, Shakhawat; Ilnytskyy, Slava; Ghose, Abhijit; Kirkby, Charles; Ghasroddashti, Esmaeel; Kovalchuk, Olga; Kolb, Bryan

    2016-01-26

    Radiation therapy can not only produce effects on targeted organs, but can also influence shielded bystander organs, such as the brain in targeted liver irradiation. The brain is sensitive to radiation exposure, and irradiation causes significant neuro-cognitive deficits, including deficits in attention, concentration, memory, and executive and visuospatial functions. The mechanisms of their occurrence are not understood, although they may be related to the bystander effects.We analyzed the induction, mechanisms, and behavioural repercussions of bystander effects in the brain upon liver irradiation in a well-established rat model.Here, we show for the first time that bystander effects occur in the prefrontal cortex and hippocampus regions upon liver irradiation, where they manifest as altered gene expression and somewhat increased levels of γH2AX. We also report that bystander effects in the brain are associated with neuroanatomical and behavioural changes, and are more pronounced in females than in males.

  16. Effect of low frequency low energy pulsing electromagnetic field (PEMF) on X-ray-irradiated mice

    SciTech Connect

    Cadossi, R.; Hentz, V.R.; Kipp, J.; Eiverson, R.; Ceccherelli, G.; Zucchini, P.; Emilia, G.; Torelli, G.; Franceschi, C.; Cossarizza, A.

    1989-02-01

    C3H/Km flora-defined mice were used to investigate the effect of exposure to pulsing electromagnetic field (PEMF) after total body x-ray irradiation. Prolonged exposure to PEMF had no effect on normal nonirradiated mice. When mice irradiated with different doses of x-ray (8.5 Gy, 6.8 Gy, and 6.3 Gy) were exposed to PEMF 24 h a day, we observed a more rapid decline in white blood cells (WBC) in the peripheral blood of mice exposed to PEMF at all the x-ray dosages used. No effect of exposure to PEMF was observed on the survival of the mice irradiated with 6.3 Gy and 8.5 Gy; in mice irradiated with 6.8 Gy, 2 out of 12 survived when exposed to PEMF as compared to 10 out of 12 control mice that were irradiated only. At day 4 after irradiation autoradiographic studies performed on bone marrow and spleen of 8.5-Gy-irradiated mice showed no difference between controls and mice exposed to PEMF, whereas on 6.8-Gy mice the bone marrow labeling index was lower in mice exposed to PEMF. In mice irradiated to 6.3 Gy we observed that the recovery of WBC in the peripheral blood was slowed in mice exposed to PEMF and their body weight was significantly lower than in control mice that were irradiated only. The spleen and bone marrow of the mice irradiated to 6.3 Gy and sacrificed at days 4, 14, 20, and 25 after irradiation were analyzed by autoradiography to evaluate the labeling index. Half of the spleens from mice sacrificed at day 25 after irradiation were used to evaluate the RNA content. Autoradiography showed that in the spleen and bone marrow of control mice, there were more cells labeled with (3H)thymidine at days 4 and 14 and less at days 20 and 25 after irradiation in comparison with mice irradiated and exposed to PEMF.

  17. Effects of low-level gamma irradiation on the characteristics of fermented pork sausage during storage

    NASA Astrophysics Data System (ADS)

    Kim, I. S.; Jo, C.; Lee, K. H.; Lee, E. J.; Ahn, D. U.; Kang, S. N.

    2012-04-01

    The effect of gamma irradiation (0.5, 1, 2, and 4 kGy) on the quality of vacuum-packaged dry fermented sausages during refrigerated storage was evaluated. At Day 0 of irradiation, the pH, redness (CIE a*), yellowness (CIE b*), 2-thiobarbituric acid-reactive substances (TBARS) and volatile basic nitrogen (VBN) values of samples irradiated at 2 and 4 kGy were higher (p<0.05), but the CIE L* values (lightness) were lower than those of the non-irradiated control (p<0.05). At<1 kGy irradiation, however, the pH, CIE L*, CIE a* and CIE b*-value of samples were not significantly influenced by irradiation. The CIE a*, and CIE b*-values of samples irradiated at 2 and 4 kGy decreased with the increase of storage time. The VBN, TBARS, and CIE L*-values of samples irradiated at 4 kGy were not changed significantly during refrigerated storage for 90 days (p>0.05). The total plate counts (TPC) and lactic acid bacteria (LAB) in the samples irradiated at 4 kGy were significantly lower (p<0.01) than those with lower irradiation doses. At the end of storage, the TPC, coliform, and LAB in the samples were not increased after irradiation at 1, 0.5 and 1 kGy, respectively. TPC and LAB were not detected in samples irradiated at 4 kGy at Day 90. In addition, no coliform bacteria were found in samples irradiated at 1 kGy during refrigerated storage. Sensory evaluation indicated that the rancid flavor of samples irradiated at 4 kGy was significantly higher, but aroma and taste scores were lower than those of the control at Day 3 of storage. Irradiation of dry fermented sausages at 2 kGy was the best conditions to prolong the shelf-life and decrease the rancid flavor without significant quality deterioration.

  18. Effect of irradiated dib-cAMP on the tonic and phasic activity of human myometrium.

    PubMed

    Schachinger, L; Srivastava, A; Schippel, C; Klöter, H

    1983-06-01

    Cyclic AMP, used as dibutyryl derivative for better permeability, has a relaxing effect on smooth muscle preparations from human uterine tissue (surgical material). The observed decrease of tonus and frequency depends on the concentration applied, shown in the range between 50 and 300 microM. cAMP looses its physiological activity by irradiation in vitro; in addition an inhibitory action of the irradiation products on uterine tissue could be proved. From the data of the Lineweaver-Burk plots, showing the competition between non-irradiated and irradiated cAMP, a ten-to twentyfold higher affinity of the irradiation products to the receptor compared to that of this transmitter could be calculated. The results show that preparations of human origin with beta-receptors behave similarly to animal tissues with beta-receptors. They are further discussed with respect to a better understanding of dose-response curves for chemical and physiological inactivation.

  19. Irradiation temperature effects on the induced point defects in Ge-doped optical fibers.

    NASA Astrophysics Data System (ADS)

    Alessi, A.; Reghioua, I.; Girard, S.; Agnello, S.; Di Francesca, D.; Martin-Samos, L.; Marcandella, C.; Richard, N.; Cannas, M.; Boukenter, A.; Ouerdane, Y.

    2017-02-01

    We present an experimental investigation on the combined effects of temperature and irradiation on Ge-doped optical fibers. Our samples were X-ray (10 keV) irradiated up to 5 kGy with a dose rate of 50 Gy(SiO2)/s changing the irradiation temperature in the range 233-573 K. After irradiation we performed electron paramagnetic resonance (EPR) and confocal microscopy luminescence (CML) measurements. The recorded data prove the generation of different Ge related paramagnetic point defects and of a red emission, different from that of the Ge/Si Non-Bridging Oxygen Hole center. Furthermore, by comparing the behaviour of the EPR signal of the Ge(1) as a function of the irradiation temperature with the one of the red emission we can exclude that this emission is originated by the Ge(1).

  20. Effect of ion irradiation on the interdiffusion growth of aluminide phases in Ti Al diffusion couple

    NASA Astrophysics Data System (ADS)

    Romankov, S. E.; Mamaeva, A.; Vdovichenko, E.; Ermakov, E.

    2005-08-01

    During annealing on the Ti surface coated by the Al film, different aluminide phases were formed as the result of reactions between Ti and Al. Preliminary irradiation of the Al film with the thickness of 7 μm by Ti + ions had a strong effect on the interdiffusion growth of aluminide phases on the Ti substrate. Preliminary ion irradiation resulted in the development of more homogeneous and fine-grain microstructure during subsequent annealing. During ion irradiation of the two-phase (TiAl + Ti 3Al) overlayer the decomposition of the TiAl compound and the formation of Ti 3Al happened. In the processing of subsequent annealing, diffusion cementation of the overlayer occurred faster on the surface of the irradiated samples. After irradiation by different ions (Ti + and Al +), and during subsequent annealing the kinetics of structural formation developed in a different way.

  1. Effects of high-energy electron irradiation of chicken meat on Salmonella and aerobic plate count

    SciTech Connect

    Heath, J.L.; Owens, S.L.; Tesch, S.; Hannah, K.W. )

    1990-01-01

    Four experiments were used to determine the effects of high-energy irradiation on the number of aerobic microorganisms and Salmonella on broiler breasts and thighs. Irradiation ranging from 100 to 700 kilorads (krads) was provided by a commercial-scale, electron-beam accelerator. Irradiation of broiler breast and thigh pieces with electron beams at levels of 100, 200, 300, 400, 500, and 600 krads showed that levels as low as 100 krads would eliminate Salmonella. When 33 thighs were tested after irradiation at 200 krads, only one thigh tested presumptive positive. The total number of aerobic organisms was reduced by 2 to 3 log10 cycles at irradiation levels of 100, 200, 300, 400, 500, 600, and 700 krads. Increasing the dose above 100 krads gave little if any additional benefit.

  2. Irradiation Effect on Oxidative Condition and Tocopherol Content of Vegetable Oils

    PubMed Central

    Lalas, Stavros; Gortzi, Olga; Tsaknis, John; Sflomos, Konstantinos

    2007-01-01

    The effect on induction period and tocopherol content after γ-irradiation on samples of olive oil and seed oils (sunflower and soybean) was determined. In seed oil samples 0, 100, 200 and 300 ppm of δ-tocopherol were added before irradiation with 1, 2 and 3kGy. The results of induction period showed that, after irradiation, all samples presented a significant decreased in resistance to oxidation. However, this decrease was minimized when δ-tocopherol was added. Irradiation significantly decreased the level of tocopherols. δ-Tocopherol appeared more sensitive in irradiation process than α- and γ-tocopherol. The addition of δ-tocopherol significantly reduced, in most cases, the depletion of the other tocopherols.

  3. Effects of visible light irradiation on eugenol-treated oral mucosa.

    PubMed

    Fujisawa, Seiichiro; Muraoka, Eitoku; Nakazato, Yoshihiro; Okada, Norihisa

    2005-06-01

    The purpose of this study was to evaluate the histopathological effects of eugenol (EUG) and iso-eugenol (IsoEUG)--with or without visible light (VL) irradiation--on oral mucous membranes. Oral mucous membranes of mice were applied with three agents, EUG, IsoEUG, and aceton (as the control) in the absence or presence of VL irradiation. VL irradiation resulted in more tissue damage for EUG- or IsoEUG-treated mucosa compared to corresponding compounds without VL irradiation, and that damage under IsoEUG treatment was greater than that under EUG treatment. Necrosis, but not apoptosis, was preferentially expressed in EUG- or IsoEUG-treated mucous membranes in the presence of VL irradiation.

  4. In vivo 3D analysis of systemic effects after local heavy-ion beam irradiation in an animal model.

    PubMed

    Nagata, Kento; Hashimoto, Chika; Watanabe-Asaka, Tomomi; Itoh, Kazusa; Yasuda, Takako; Ohta, Kousaku; Oonishi, Hisako; Igarashi, Kento; Suzuki, Michiyo; Funayama, Tomoo; Kobayashi, Yasuhiko; Nishimaki, Toshiyuki; Katsumura, Takafumi; Oota, Hiroki; Ogawa, Motoyuki; Oga, Atsunori; Ikemoto, Kenzo; Itoh, Hiroshi; Kutsuna, Natsumaro; Oda, Shoji; Mitani, Hiroshi

    2016-06-27

    Radiotherapy is widely used in cancer treatment. In addition to inducing effects in the irradiated area, irradiation may induce effects on tissues close to and distant from the irradiated area. Japanese medaka, Oryzias latipes, is a small teleost fish and a model organism for evaluating the environmental effects of radiation. In this study, we applied low-energy carbon-ion (26.7 MeV/u) irradiation to adult medaka to a depth of approximately 2.2 mm from the body surface using an irradiation system at the National Institutes for Quantum and Radiological Science and Technology. We histologically evaluated the systemic alterations induced by irradiation using serial sections of the whole body, and conducted a heart rate analysis. Tissues from the irradiated side showed signs of serious injury that corresponded with the radiation dose. A 3D reconstruction analysis of the kidney sections showed reductions in the kidney volume and blood cell mass along the irradiated area, reflecting the precise localization of the injuries caused by carbon-beam irradiation. Capillary aneurysms were observed in the gill in both ventrally and dorsally irradiated fish, suggesting systemic irradiation effects. The present study provides an in vivo model for further investigation of the effects of irradiation beyond the locally irradiated area.

  5. In vivo 3D analysis of systemic effects after local heavy-ion beam irradiation in an animal model

    PubMed Central

    Nagata, Kento; Hashimoto, Chika; Watanabe-Asaka, Tomomi; Itoh, Kazusa; Yasuda, Takako; Ohta, Kousaku; Oonishi, Hisako; Igarashi, Kento; Suzuki, Michiyo; Funayama, Tomoo; Kobayashi, Yasuhiko; Nishimaki, Toshiyuki; Katsumura, Takafumi; Oota, Hiroki; Ogawa, Motoyuki; Oga, Atsunori; Ikemoto, Kenzo; Itoh, Hiroshi; Kutsuna, Natsumaro; Oda, Shoji; Mitani, Hiroshi

    2016-01-01

    Radiotherapy is widely used in cancer treatment. In addition to inducing effects in the irradiated area, irradiation may induce effects on tissues close to and distant from the irradiated area. Japanese medaka, Oryzias latipes, is a small teleost fish and a model organism for evaluating the environmental effects of radiation. In this study, we applied low-energy carbon-ion (26.7 MeV/u) irradiation to adult medaka to a depth of approximately 2.2 mm from the body surface using an irradiation system at the National Institutes for Quantum and Radiological Science and Technology. We histologically evaluated the systemic alterations induced by irradiation using serial sections of the whole body, and conducted a heart rate analysis. Tissues from the irradiated side showed signs of serious injury that corresponded with the radiation dose. A 3D reconstruction analysis of the kidney sections showed reductions in the kidney volume and blood cell mass along the irradiated area, reflecting the precise localization of the injuries caused by carbon-beam irradiation. Capillary aneurysms were observed in the gill in both ventrally and dorsally irradiated fish, suggesting systemic irradiation effects. The present study provides an in vivo model for further investigation of the effects of irradiation beyond the locally irradiated area. PMID:27345436

  6. Thermal Effects Induced by Laser Irradiation of Solids

    SciTech Connect

    Galovic, S.

    2004-12-01

    A part of incident energy is absorbed within the irradiated sample when a solid is exposed to the influence of laser radiation, to more general electromagnetic radiation within the wide range of wavelengths (from microwaves, to infrared radiation to X-rays), or to the energy of particle beams (electronic, protonic, or ionic). The absorption process signifies a highly selective excitation of the electronic state of atoms or molecules, followed by thermal and non-thermal de-excitation processes. Non-radiation de-excitation-relaxation processes induce direct sample heating. In addition, a great number of non-thermal processes (e.g., photoluminescence, photochemistry, photovoltage) may also induce heat generation as a secondary process. This method of producing heat is called the photothermal effect.The photothermal effect and subsequent propagation of thermal waves on the surface and in the volume of the solid absorbing the exciting beam may produce the following: variations in the temperature on the surfaces of the sample; deformation and displacement of surfaces; secondary infrared radiation (photothermal radiation); the formation of the gradient of the refractivity index; changes in coefficients of reflection and absorbtion; the generation of sound (photoacoustic generation), etc. These phenomena may be used in the investigation and measurement of various material properties since the profile and magnitude of the generated signal depend upon the nature of material absorbing radiation. A series of non-destructive spectroscopic, microscopic and defectoscopic detecting techniques, called photothermal methods, is developed on the basis of the above-mentioned phenomena.This paper outlines the interaction between the intensity modulated laser beam and solids, and presents a mathematical model of generated thermal sources. Generalized models for a photothermal response of optically excited materials have been obtained, including thermal memory influence on the propagation

  7. Evaluation of irradiation effects of 16 MeV proton-irradiated 12Cr-1MoV steel by small punch (SP) tests

    SciTech Connect

    Chi, S.H.; Hong, J.H. ); Kim, I.S. . Dept. of Nuclear Engineering)

    1994-06-15

    Recently, interest in small-scale specimens for testing irradiated materials has arisen in conjunction with the need to develop materials for fusion reactor materials and to study irradiation effects using an ion irradiation facility. Several attempts have been made to evaluate material property changes due to irradiation using a small specimen technique. The SP (small punch) test is an example of small-scale specimen test techniques, originally developed by Baik et al. to estimate DBTT (ductile-to-brittle transition temperature) using broken standard CVN (Charpy 5-notch) specimens. The objective of the present study is to evaluate 16 MeV proton irradiation effects on a fusion reactor candidate material in terms of changes in energy up to failure and J[sub IC] fracture toughness (SP J[sub IC]) by using a SP test technique and a J[sub IC] - [bar [epsilon

  8. Short-Term Peripheral Auditory Effects of Cranial Irradiation: A Mouse Model

    PubMed Central

    Gasser Rutledge, Krysta L.; Prasad, Kumar G.; Emery, Kara R.; Mikulec, Anthony A.; Varvares, Mark; Gratton, Michael Anne

    2015-01-01

    Objectives Assess post-cranial irradiation short-term threshold shift short-term peripheral auditory histopathology the mouse as an experimental model Methods Adult mice were exposed to single-dose radiation of 10 – 60 Gy. Pre- and post-irradiation (baseline, 2 – 8 days) audiometric brainstem response data were recorded with analysis of cochlear ultrastructure. Results Significant threshold shift occurred at all test frequencies in mice exposed to ≥ 20 Gy at 4 – 6 days post-irradiation. Ultrastructurally in Rosenthal’s canal and the spiral lamina, neuronal density and extracellular matrix decreased dramatically. There was overall preservation of hair cells, stria vascularis, and vasculature. No difference within Gy group was noted in the frequency or severity of pathology along the length of the cochlea. Conclusions The initial impact of radiation in the first week post-exposure focuses on spiral ganglion cell bodies and peripheral projections, resulting in significant threshold shift for irradiation dosages ≥ 20 Gy. This study demonstrates that the mouse is a viable model for study of short-term peripheral auditory effects using single-dose cranial irradiation. Additionally, with access to a precise animal irradiator, the mouse may be used as an experimental model for a fractionated irradiation dosage of 10 Gy, simulating stereotactic therapeutic cranial irradiation. PMID:26085370

  9. Effect of irradiation on the parameters that influence quality characteristics of raw turkey breast meat

    NASA Astrophysics Data System (ADS)

    Feng, Xi; Moon, Sun Hee; Lee, Hyun Yong; Ahn, Dong Uk

    2017-01-01

    This study was designed to elucidate the mechanisms of quality changes in raw turkey breast meat by irradiation. Raw turkey breast meat was irradiated at 0 kGy, 1.5 kGy, 3.0 kGy and 4.5 kGy, and changes in quality parameters including color, lipid and protein oxidation, and off-odor volatiles were determined. Irradiation accelerated lipid and protein oxidation, and increased redness in raw turkey breast meat. However, irradiation had less effect on the volatile profiles of salt-soluble muscle extract than water-soluble muscle extract because the primary radiolytic product from water (hydroxyl radical) had higher chances to react with the water-soluble molecules nearby. The radiolytic degradation products from sulfur-containing amino acids and aldehydes from lipid oxidation were two major volatile compounds responsible for the off-odor of irradiated raw turkey breast meat. Dimethyl disulfide was found only in irradiated raw turkey breast meat, and the amount of dimethyl disulfide linearly increased as the irradiation dose increased, indicating that this compound can be used as a marker for irradiate meat.

  10. Effect of gamma irradiation on the hemocyte-mediated immune response of Aedes aegypti against microfilariae

    SciTech Connect

    Christensen, B.M.; Huff, B.M.; Li, J. )

    1990-07-01

    The effect of gamma irradiation on the melanotic encapsulation response of Aedes aegypti black eye Liverpool strain against inoculated Dirofilaria immitis microfilariae (mff) was assessed at 1, 2, 3, and 6 days postinoculation (PI). Mosquitoes received 6000 rad from a 137Cs source (Shepard Mark I irradiator) at 3 days postemergence and were inoculated with 15-20 mff 24 hr later. These mosquitoes were compared to nonirradiated controls that also were inoculated with 15-20 mff at 3 days postemergence. The immune response was significantly reduced in irradiated mosquitoes as compared with controls at all days PI. Although the response was significantly inhibited compared with controls, irradiated mosquitoes were still capable of eliciting a response against 69% of recovered mff at 6 days PI. External gamma irradiation did not significantly affect the proliferation of hemocytes associated with the melanotic encapsulation response of A. aegypti. The number of circulating hemocytes increased in irradiated mosquitoes in response to inoculated mff in a manner similar to nonirradiated, inoculated controls. Hemocyte monophenol oxidase activity, however, was significantly reduced in gamma-irradiated mosquitoes at 12 hr PI as compared with controls. The reduced immunological capacity of irradiated mosquitoes might be related to an interference with gene activity required for the synthesis or activation of enzymes that are directly or indirectly involved in the biochemical processes associated with the production of melanotic substances that sequester mff.

  11. Effect of irradiation and thermal annealing on quartz materials luminescence

    NASA Astrophysics Data System (ADS)

    Korovkin, M. V.; Ananyeva, L. G.

    2017-01-01

    X-ray and gamma-quanta irradiation of radiation-resistant quartz materials including natural and synthetic quartz crystals and high-purity quartzite causes the luminescence in the ultraviolet range (365 nm), thermally stimulated luminescence and radiofrequency electromagnetic emission. Preliminary radiation and thermal annealing improves luminescence properties of quartz materials.

  12. Irradiation effects in tungsten-copper laminate composite

    NASA Astrophysics Data System (ADS)

    Garrison, L. M.; Katoh, Y.; Snead, L. L.; Byun, T. S.; Reiser, J.; Rieth, M.

    2016-12-01

    Tungsten-copper laminate composite has shown promise as a structural plasma-facing component as compared to tungsten rod or plate. The present study evaluated the tungsten-copper composite after irradiation in the High Flux Isotope Reactor (HFIR) at temperatures of 410-780 °C and fast neutron fluences of 0.02-9.0 × 1025 n/m2, E > 0.1 MeV, 0.0039-1.76 displacements per atom (dpa) in tungsten. Tensile tests were performed on the composites, and the fracture surfaces were analyzed with scanning electron microscopy. Before irradiation, the tungsten layers had brittle cleavage failure, but the overall composite had 15.5% elongation at 22 °C. After only 0.0039 dpa this was reduced to 7.7% elongation, and no ductility was observed after 0.2 dpa at all irradiation temperatures when tensile tested at 22 °C. For elevated temperature tensile tests after irradiation, the composite only had ductile failure at temperatures where the tungsten was delaminating or ductile.

  13. Irradiation effects in tungsten-copper laminate composite

    SciTech Connect

    Garrison, L. M.; Katoh, Y.; Snead, L. L.; Byun, T. S.; Reiser, J.; Rieth, M.

    2016-12-01

    Tungsten-copper laminate composite has shown promise as a structural plasma-facing component as compared to tungsten rod or plate. The present study evaluated the tungsten-copper composite after irradiation in the High Flux Isotope Reactor (HFIR) at temperatures of 410-780°C and fast neutron fluences of 0.02-9.0×1025 n/m2, E>0.1 MeV, 0.0039-1.76 displacements per atom (dpa) in tungsten. Tensile tests were performed on the composites, and the fracture surfaces were analyzed with scanning electron microscopy. Before irradiation, the tungsten layers had brittle cleavage failure, but the overall composite had 15.5% elongation at 22°C. After only 0.0039 dpa this was reduced to 7.7% elongation, and no ductility was observed after 0.2 dpa at all irradiation temperatures when tensile tested at 22°C. For elevated temperature tensile tests after irradiation, the composite only had ductile failure at temperatures where the tungsten was delaminating or ductile.

  14. Assessment of Antiradiation Drug Effectiveness to Fission Neutron Irradiation.

    DTIC Science & Technology

    1982-09-01

    radiation. The decarboxylated cysteine derivative, cysteamine (mercaptoethylinine, MEA, WR 347) was found to be the best protector in the sulphydryl class...reported the synthesis of a thiophosphate derivative of cysteamine which was characterized by a phosphate group covering the sulphydryl. These... cysteamine .(S), but it also protects irradiated skin and bone marrow preferentially over tumor (9) and provides differential protection in several other

  15. Irradiation effects in tungsten-copper laminate composite

    SciTech Connect

    Garrison, L. M.; Katoh, Yutai; Snead, Lance L.; Byun, Thak Sang; Reiser, Jens; Rieth, Michael

    2016-09-19

    Tungsten-copper laminate composite has shown promise as a structural plasma-facing component as compared to tungsten rod or plate. The present study evaluated the tungsten-copper composite after irradiation in the High Flux Isotope Reactor (HFIR) at temperatures of 410–780 °C and fast neutron fluences of 0.02–9.0 × 1025 n/m2, E > 0.1 MeV, 0.0039–1.76 displacements per atom (dpa) in tungsten. Tensile tests were performed on the composites, and the fracture surfaces were analyzed with scanning electron microscopy. Before irradiation, the tungsten layers had brittle cleavage failure, but the overall composite had 15.5% elongation at 22 °C. After only 0.0039 dpa this was reduced to 7.7% elongation, and no ductility was observed after 0.2 dpa at all irradiation temperatures when tensile tested at 22 °C. In conclusion, tor elevated temperature tensile tests after irradiation, the composite only had ductile failure at temperatures where the tungsten was delaminating or ductile.

  16. Irradiation effects in tungsten-copper laminate composite

    DOE PAGES

    Garrison, L. M.; Katoh, Yutai; Snead, Lance L.; ...

    2016-09-19

    Tungsten-copper laminate composite has shown promise as a structural plasma-facing component as compared to tungsten rod or plate. The present study evaluated the tungsten-copper composite after irradiation in the High Flux Isotope Reactor (HFIR) at temperatures of 410–780 °C and fast neutron fluences of 0.02–9.0 × 1025 n/m2, E > 0.1 MeV, 0.0039–1.76 displacements per atom (dpa) in tungsten. Tensile tests were performed on the composites, and the fracture surfaces were analyzed with scanning electron microscopy. Before irradiation, the tungsten layers had brittle cleavage failure, but the overall composite had 15.5% elongation at 22 °C. After only 0.0039 dpa thismore » was reduced to 7.7% elongation, and no ductility was observed after 0.2 dpa at all irradiation temperatures when tensile tested at 22 °C. In conclusion, tor elevated temperature tensile tests after irradiation, the composite only had ductile failure at temperatures where the tungsten was delaminating or ductile.« less

  17. Mechanical properties and plasticity size effect of Fe-6%Cr irradiated by Fe ions and by neutrons

    NASA Astrophysics Data System (ADS)

    Hardie, C. D.; Odette, G. R.; Wu, Y.; Akhmadaliev, S.; Roberts, S. G.

    2016-12-01

    The mechanical behaviour of Fe6%Cr in the un-irradiated, self-ion irradiated and neutron irradiated conditions was measured and compared. Irradiations were performed to the same dose and at the same temperature but to very different damage rates for both methods. The materials were tested using nanoindentation and micromechanical testing, and compared with microstructural observations from Transmission Electron Microscopy (TEM) and Atom Probe Tomography (APT) reported elsewhere. Irradiated and un-irradiated micro-cantilevers with a wide range of dimensions were used to study the interrelationships between irradiation hardening and size effects in small-scale plasticity. TEM and APT results identified that the dislocation loop densities were ∼2.9 × 1022m-3 for the neutron irradiated material and only 1.4 × 1022m-3 for the ion irradiated material. Cr segregation to loops was only found for the neutron-irradiated material. The nanoindentation hardness increase due to neutron irradiation was 3 GPa and that due to ion irradiation 1 GPa. The differences between the effects of the two irradiation types are discussed, taking into account inconsistencies in damage calculations, and the differences in PKA spectra, dose rate and transmutation products for the two irradiation types.

  18. [Effect of electron irradiation on the structure of microsomal membrane proteins].

    PubMed

    Gorbenko, G P; Diubko, T S; Krupin, V D

    1998-01-01

    Using tryptophan fluorescence quenching by iodide and acrylamide the effect of electrons with the energy 5 Mev on the structure of microsomal membrane proteins has been studied. Conformation of microsomal proteins were found to change upon irradiation.

  19. Preparatory effects of distractor suppression: evidence from visual cortex.

    PubMed

    Munneke, Jaap; Heslenfeld, Dirk J; Usrey, W Martin; Theeuwes, Jan; Mangun, George R

    2011-01-01

    Spatial selective attention is the mechanism that facilitates the selection of relevant information over irrelevant information in the visual field. The current study investigated whether foreknowledge of the presence or absence of distractors surrounding an impending target stimulus results in preparatory changes in visual cortex. We cued the location of the target and the presence or absence of distractors surrounding the target while changes in blood oxygen level dependent (BOLD) signals were measured. In line with prior work, we found that top-down spatial attention resulted in an increased contralateral BOLD response, evoked by the cue throughout early visual cortex (areas V1, V2 and V3). In addition, cues indicating distractor presence evoked a substantial increase in the magnitude of the BOLD signal in visual area V3, but not in V2 or V1. This study shows that prior knowledge concerning the presence of a distractor results in enhanced attentional modulation of visual cortex, in visual areas where neuronal receptive fields are large enough to encompass both targets and distractors. We interpret these findings as evidence that top-down attentional control processes include active preparatory suppression mechanisms for irrelevant, distracting information in the visual scene.

  20. Gyroaverage effects on nontwist Hamiltonians: separatrix reconnection and chaos suppression

    SciTech Connect

    Del-Castillo-Negrete, Diego B; Martinell, J.

    2012-01-01

    A study of nite Larmor radius (FLR) eects on E B test particle chaotic transport in non- monotonic zonal ows with drift waves in magnetized plasmas is presented. Due to the non- monotonicity of the zonal ow, the Hamiltonian does not satisfy the twist condition. The electro- static potential is modeled as a linear superposition of a zonal ow and regular neutral modes of the Hasegawa-Mima equation. FLR eects are incorporated by gyro-averaging the EB Hamiltonian. It is shown that there is a critical value the Larmor radius for which the zonal ow transitions from a prole with one maximum to a prole with two maxima and a minimum. This bifurcation leads to the creation of additional shearless curves and resonances. The gyroaveraged nontwist Hamiltonian exhibits complex patterns of separatrix reconnection. A change in the Larmor ra- dius can lead to heteroclinic-homoclinic bifurcations and dipole formation. For Larmor radii for which the zonal ow has bifurcated, double heteroclinic-heteroclinic, homoclinic-homoclinic and heteroclinic-homoclinic topologies are observed. It is also shown that chaotic transport is typically reduced as the Larmor radius increases. Poincare sections shows that, for large enough Larmor radius, chaos can be practically suppressed. In particular, small changes on the Larmor radius can restore the shearless curve.

  1. Effects of acid suppression on microbial flora of upper gut.

    PubMed

    Yeomans, N D; Brimblecombe, R W; Elder, J; Heatley, R V; Misiewicz, J J; Northfield, T C; Pottage, A

    1995-02-01

    Decreased acid secretion, due to therapy or disease, predisposes to increased bacterial counts in gastric juice. As bacterial numbers increase, the number of nitrate-reducing strains and the concentration of luminal nitrite usually also increase. However, there is controversy (mainly because of assay problems) about whether decreased acid increases generation of N-nitroso compounds: these may be produced by acid or by bacterial catalysis, and the relative contributions of each are still uncertain. Other potentially important factors include ascorbate secretion (can prevent nitrite conversion to nitroso compounds) and the particular spectrum of nitroso compounds produced. Nitrosation of several histamine H2-receptor antagonists has been demonstrated experimentally, but under conditions that are very unlikely to be encountered clinically. Some acid suppressant therapies have been claimed to aid eradication of Helicobacter pylori, but more work is needed to evaluate this. If ulcer treatment regimens do not also address eradication of H. pylori (when present), gastritis will progress, and the recently documented association between H. pylori and gastric carcinoma needs to be considered. Enteric flora probably also increase if acid secretion is markedly reduced: this does not appear to have nutritional consequences but probably reduces the resistance to occasional infections, of which cholera is the best documented.

  2. Synergistic effect of microwave irradiation and CaF2 on vanadium leaching

    NASA Astrophysics Data System (ADS)

    Wang, Jing-peng; Zhang, Yi-min; Huang, Jing; Liu, Tao

    2017-02-01

    The effect and mechanism of microwave irradiation on vanadium leaching were studied via a comparison between microwave heating and conventional heating. The results show a synergistic effect of microwave irradiation and calcium fluoride (CaF2) on the vanadium leaching efficiency. It is confirmed that the vanadium leaching process can be improved by microwave irradiation when CaF2 is present. The leaching rate of vanadium under microwave irradiation is increased by 8%-15% when 5wt% CaF2 is added; by contrast, in the absence of CaF2, the leaching rate is almost unaffected compared to that by conventional heating. Morphological analysis reveals that the particles are gradually eroded by acid under microwave irradiation, whereas some of the fine particles in samples subjected to conventional heating are tightly covered by a flocculent silicate product. Moreover, a large amount of Al and V and a small amount of Si are dissolved from samples under microwave heating, as revealed by the elemental analysis of leachates. Fourier transform infrared spectroscopic analysis also indicates a higher mass transfer coefficient in the diffusion layer of the raw material by microwave irradiation. When CaF2 is present, the reaction energy barrier is lowered and the leaching process is controlled by the tightly covered product layer, resulting in a prominent effect of microwave irradiation.

  3. Molecular Effects of Irradiation (Cobalt-60) on the Control of Panonychus citri (Acari: Tetranychidae)

    PubMed Central

    Zhang, Ke; Luo, Lingyan; Chen, Xieting; Hu, Meiying; Hu, Qiongbo; Gong, Liang; Weng, Qunfang

    2015-01-01

    The effective dose of irradiation to control pest mites in quarantine has been studied extensively, but the molecular mechanisms underlying the effects of the irradiation on mites are largely unknown. In this study, exposure to 400 Gy of γ rays had significant (p < 0.05) effects on the adult survival, fecundity and egg viability of Panonychus citri. The irradiation caused the degradation of the DNA of P. citri adults and damaged the plasma membrane system of the egg, which led to condensed nucleoli and gathered yolk. Additionally, the transcriptomes and gene expression profiles between irradiated and non-irradiated mites were compared, and three digital gene expression libraries were assembled and analyzed. The differentially expressed genes were putatively involved in apoptosis, cell death and the cell cycle. Finally, the expression profiles of some related genes were studied using quantitative real-time PCR. Our study provides valuable information on the changes in the transcriptome of irradiated P. citri, which will facilitate a better understanding of the molecular mechanisms that cause the sterility induced by irradiation. PMID:26569230

  4. Effect of gamma irradiation on microbiological, chemical, and sensory properties of fresh ashitaba and kale juices

    NASA Astrophysics Data System (ADS)

    Jo, Cheorun; Ahn, Dong Uk; Lee, Kyung Haeng

    2012-08-01

    Due to the popularity of health effects upon intake of fresh fruits and vegetables, the demand for fresh vegetables and fruit juices has rapidly increased. However, currently, washing is the only procedure for reducing contaminated microorganisms, which obviously limits the shelf-life of fresh vegetable juice (less than 3 days). In this study, we examined the effects of irradiation on the microbiological, chemical and sensory properties of ashitaba and kale juices for industrial application and possible shelf-life extension. Freshly made ashitaba and kale juices already had 2.3×105 and 9.5×104 CFU/mL, respectively. Irradiation of 5 kGy induced higher than 2 decimal reductions in the microbial level, which was consistently maintained during storage for 7 days under refrigerated conditions. Total content of ascorbic acid in vegetable juice decreased upon irradiation in a dose-dependent manner. However, the content of flavonoids did not change, whereas that of polyphenols increased upon irradiation. In sensory evaluation, the ashitaba and kale juices without irradiation (control) scored lower than the irradiated samples after 1 and 3 days, respectively. This study confirms that irradiation is an effective method for sterilizing fresh vegetable juice without compromising sensory property, which cannot be subjected to heat pasteurization due to changes in the bioactivities of the products.

  5. Effects of ascorbic acid and antioxidants on color, lipid oxidation and volatiles of irradiated ground beef

    NASA Astrophysics Data System (ADS)

    Ahn, D. U.; Nam, K. C.

    2004-09-01

    Beef loins with 3 different aging times after slaughter were ground, added with none, 0.1% ascorbic acid, 0.01% sesamol+0.01% α-tocopherol, or 0.1% ascorbic acid+0.01% sesamol+0.01% tocopherol. The meats were packaged in oxygen-permeable bags, irradiated at 2.5 kGy, and color, oxidation-reduction potential (ORP), lipid oxidation and volatile profiles were determined. Irradiation decreased the redness of ground beef, and visible color of beef changed from a bright red to a green/brown depending on the age of meat. Addition of ascorbic acid prevented color changes in irradiated beef, and the effect of ascorbic acid became greater as the age of meat or storage time after irradiation increased. The ground beef added with ascorbic acid had lower ORP than control, and the low ORP of meat helped maintaining the heme pigments in reduced form. During aerobic storage, S-volatiles disappeared while volatile aldehydes significantly increased in irradiated beef. Addition of ascorbic acid at 0.1% or sesamol+α-tocopherol at each 0.01% level to ground beef prior to irradiation were effective in reducing lipid oxidation and S-volatiles. As storage time increased, however, the antioxidant effect of sesamol+tocopherol in irradiated ground beef was superior to that of ascorbic acid.

  6. Long-term bioavailability of redox nanoparticles effectively reduces organ dysfunctions and death in whole-body irradiated mice.

    PubMed

    Feliciano, Chitho P; Tsuboi, Koji; Suzuki, Kenshi; Kimura, Hiroyuki; Nagasaki, Yukio

    2017-06-01

    Radioprotective agents have been developed to protect patients against the damaging and lethal effects of ionizing radiation. However, in addition to the intrinsic ability to target reactive oxygen species (ROS), the ability to retain a significant level of bioavailability is desirable in radioprotective agents because that would increase and prolong their radioprotective efficacy and improve its safety. Here, we report the development of a novel nanoparticle-based radioprotective agent with improved bioavailability, which suppressed the adverse effects typically associated with low-molecular-weight (LMW) antioxidants. We developed biocompatible and colloidally stable nanoparticles in which nitroxide radicals that were covalently conjugated (redox nanoparticles, RNP(N)) effectively scavenged radiation-induced ROS with a characteristically prolonged bioavailability and tissue-residence time compared with that of conventional LMW antioxidants. The confinement of the nitroxide radicals in the RNP(N) core prevented its rapid metabolism and excretion out of the body. The nano-sized formulation prevented internalization of RNP(N) in healthy cells, thereby preserving the normal function of the redox reactions in the cell. This improved pharmacological performance dramatically reduced the radiation-induced organ dysfunctions and increased the survival time of the lethally irradiated mice when the nanoparticles were administered 3-24 h before whole-body irradiation.

  7. Effect of mercerization and gamma irradiation on the dyeing behaviour of cotton using stilbene based direct dye

    NASA Astrophysics Data System (ADS)

    Bhatti, Ijaz Ahmad; Adeel, Shahid; Fazal-ur-Rehman; Irshad, Misbah; Abbas, Muhammad

    2012-07-01

    The dyeing behaviour of mercerized and gamma irradiated cotton fabric using stilbene based direct dye has been investigated. The fabric was treated with different concentrations of alkali to optimize the mercerization. The optimum mercerized cotton fabric was irradiated to absorbed doses of 2, 4, 6, 8 and 10 kGy using Cs-137 gamma irradiator. Dyeing was performed using irradiated and un-irradiated cotton with dye solutions. The dyeing parameters such as temperature, time of dyeing, pH of dyeing solutions and salt concentration were optimized. The colour strength values of dyed fabrics were evaluated by comparing irradiated and un-irradiated cotton in CIE Lab system using Spectra flash SF650. Methods suggested by International Standard Organization (ISO) were employed to study the effect of gamma irradiation on the colourfastness properties of dyed fabric. It was found that mercerized and irradiated cotton have not only improved the colour strength but enhanced the rating of fastness properties also.

  8. The effect of titrated fentanyl on suppressed cough reflex in healthy adult volunteers.

    PubMed

    Kelly, H E; Shaw, G M; Brett, C N; Greenwood, F M; Huckabee, M L

    2016-05-01

    Cough suppression is part of the pharmacodynamic profile of opioids. We investigated the impact of clinical doses of fentanyl on suppressing the cough reflex. Thirteen volunteers received 2 μg.kg(-1) of fentanyl in a divided administration protocol. Three minutes after each administration and at 10 min intervals during washout, suppressed cough reflex testing with nebulised citric acid was performed and compared with fentanyl effect-site concentration. Mean (SD) citric acid concentration provoking cough increased from 0.5 (0.28) mol.l(-1) at baseline to 1.2 (0.50) mol.l(-1) after 2 μg.kg(-1) of fentanyl (p = 0.01). Mean (SD) fentanyl effect-site concentration after the final dose of fentanyl was 1.89 (0.05) ng.ml(-1) . A strong positive correlation was found between suppressed cough reflex thresholds and fentanyl effect-site concentrations during both fentanyl administration and washout phases of the study (r(2) = 0.79, p = 0.01). The mean (SD) length of time for return of suppressed cough response was 44.6 (18.8) min. Clinically relevant doses of fentanyl produced cough reflex suppression in healthy volunteers.

  9. Neutron Irradiation Effects on Fatigue Crack Propagation in Type 316 Stainless Steels at 649 C.

    DTIC Science & Technology

    1980-08-01

    maintaining the maximum tensile load constant for selected time periods duriig each cycle. Induction heating was employed to achieve a test temperature of...7 AD-A OB 052 NAVAL RESEAR ICH LAS WASHINGTON DC F/6 11/BNEUTRON IRRADIATION EFFECTS ON FATIGUE CRACK PROPAGATION IN TYP-EC(UlU UNL AUG 80 0 .J...and Identify by block number) Radiation Microstruture B Irradiation Fatigue Stainless steels Crack propagation Radiation effects High temperature V

  10. Effect of gamma irradiation on physical characteristics of Jordanian durum wheat and quality of semolina and lasagna products

    NASA Astrophysics Data System (ADS)

    Azzeh, F. S.; Amr, A. S.

    2009-09-01

    This study was conducted to determine the effect of using varying gamma irradiation doses on the physiochemical and rheological properties of semolina and its products. Ash, protein and water content were not influenced with gamma irradiation, while falling number and fungi counts decreased with increasing irradiation dose. Irradiation adversely affected wet gluten at 5 kGy dose. Dough stability was deteriorated vigorously with increasing irradiation dose. Sensory evaluation showed that lasagna produced from 0.25- and 1 kGy-irradiated semolina did not show any significant differences as compared with the control sample.

  11. Effect of Wenxin Keli and Quinidine to Suppress Arrhythmogenesis in an Experimental Model of Brugada Syndrome

    PubMed Central

    Minoura, Yoshino; Panama, Brian K.; Nesterenko, Vladislav V.; Betzenhauser, Matthew; Barajas-Martínez, Hector; Hu, Dan; Di Diego, José M.; Antzelevitch, Charles

    2013-01-01

    Background Wenxin Keli (WK), a Chinese herb extract, is reported to be effective in the treatment of atrial and ventricular cardiac arrhythmias. Recent studies suggest that WK inhibits the transient outward current (Ito). Objective The present study examines the effectiveness of WK, alone and in combination with quinidine, to suppress arrhythmogenesis in an experimental model of Brugada syndrome (BrS). Methods and Results Action potential and ECG recordings were obtained from epicardial and endocardial sites of coronary-perfused canine right ventricular wedge preparations. The Ito agonist NS5806 (10–15 μM) was used to pharmacologically mimic a genetic predisposition to BrS. The Ito agonist induced Phase 2 reentry (P2R) in 13/19 preparations and polymorphic ventricular tachycardia (pVT) in 11/19 wedge preparations. WK (10g/L) suppressed P2R and pVT in 100% (3/3) of preparations. A lower concentration of WK (5g/L) suppressed P2R in 60% (3/5) and pVT in 50% (2/4), but in combination with a low concentration of quinidine (5 μM) was 100% effective in suppressing P2R and pVT. Quinidine alone suppressed P2R and pVT in 60% (3/5) and 50% (2/4), respectively and in combination with WK (5g/L) suppressed P2R and pVT by 80% (4/5) and 75% (3/4), respectively. WK reduced Ito, ICa and contractility in single cardiomyocytes, but dose-dependently increased contractility in intact wedge preparations, an effect mimicked by tyramine. Conclusions Our data provide support for the hypothesis that Wenxin Keli, particularly in combination with quinidine, effectively suppresses arrhythmogenesis in an experimental model of BrS via inhibition of Ito and indirect adrenergic sympathomimetic effects. PMID:23499631

  12. The effects of Pycnogenol(®) on colon anastomotic healing in rats given preoperative irradiation.

    PubMed

    Değer, K Cumhur; Şeker, Ahmet; Özer, Ilter; Bostancı, E Birol; Dalgıç, Tahsin; Akmansu, Müge; Ekinci, Özgür; Erçin, Uğur; Bilgihan, Ayşe; Akoğlu, Musa

    2013-01-01

    Pycnogenol(®) has excellent radical scavenging properties and enhances the production of antioxidative enzymes which contributes to the anti-inflammatory effect of the extract. Irradiation delivered to the abdominal region, typically results in severe damage to the intestinal mucosa. The effects of ionizing radiation are mediated by the formation of free radicals through radiolysis. Irradiation has local effects on tissues. These local effects of irradiation on the bowel are believed to involve a two-stage process which includes both short and long term components. In our study we aimed to investigate the short term effects of Pycnogenol(®) on the healing of colon anastomoses in irradiated bowel. Sixty male Wistar-Albino rats were used in this study. There were three groups: Group I, control group (n = 20); group II which received preoperative irradiation (n = 20); group III which received per oral Pycnogenol(®) before irradiation (n = 20). Only segmeter colonic resection and anastomosis was performed to the control group (Group I). The other groups (Group II, III) underwent surgery on the 5th day after pelvic irradiation. On postoperative days 3 and 7, half of the rats in each group were sacrificed and then relaparotomy was performed. There was no statistical difference between groups with respect to biochemical parameters. Bursting pressure was significantly higher in the Control and Group III compared with the Group II. In conclusion, the present study showed that preoperative irradiation effect negatively on colonic anastomoses in rats by means of mechanical parameters and administration of Pycnogenol(®) preoperatively ameliorates this unfavorable effect.

  13. Effects of He-Ne regional irradiation on 53 cases in the field of pediatric surgery

    NASA Astrophysics Data System (ADS)

    Guo, Jing-Zhen

    1991-06-01

    We report the clinical observation of the effect on 53 surgical cases with Helium-Neon laser local irradiation therapy. Of those cases 15 were suffered from chronic and acute infection, 5 were traumatic, 15 of hemangioma had been treated by solid CO freezing therapy and sclerosing injection previously. 18 cases were received incisional irradiation postoperatively. All showed remarkable results. There were no infection, and the healing process was shortened by Helium-Neon laser local irradiation for 2-3 days. The results showed that the curative rate was 88.68%, the marked effective rate was 9.43%, and the fair was 1.89$. We emphasize that because of the characteristic of anatomical physiology and histology in children. so the result in children is better than in adults. Thus, we strongly recommend using Helium-Laser local irradiation in surgical pediatric field. It is reliable, safe, painless, convenient, economic, and no side effects at all.

  14. Effect of gamma irradiation on the wear behaviour of human tooth enamel

    NASA Astrophysics Data System (ADS)

    Qing, Ping; Huang, Shengbin; Gao, Shanshan; Qian, Linmao; Yu, Haiyang

    2015-06-01

    Radiotherapy is a frequently used treatment for oral cancer. Extensive research has been conducted to detect the mechanical properties of dental hard tissues after irradiation at the macroscale. However, little is known about the influence of irradiation on the tribological properties of enamel at the micro- or nanoscale. Therefore, this study aimed to investigate the effect of gamma irradiation on the wear behaviour of human tooth enamel in relation to prism orientation. Nanoscratch tests, surface profilometer and scanning electron microscope (SEM) analysis were used to evaluate the friction behaviour of enamel slabs before and after treatment with identical irradiation procedures. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were performed to analyse the changes in crystallography and chemical composition induced by irradiation. Surface microhardness (SMH) alteration was also evaluated. The results showed that irradiation resulted in different scratch morphologies, friction coefficients and remnant depth and width at different loads. An inferior nanoscratch resistance was observed independent of prism orientation. Moreover, the variation of wear behaviours was closely related to changes in the crystallography, chemical composition and SMH of the enamel. Together, these measures indicated that irradiation had a direct deleterious effect on the wear behaviour of human tooth enamel.

  15. The effect of melatonin on peripheral blood cells during total body irradiation in rats.

    PubMed

    Koc, Mehmet; Buyukokuroglu, Mehmet Emin; Taysi, Seyithan

    2002-05-01

    Melatonin, has been reported to participate in the regulation of a number of important physiological and pathological process. It has also the ability to protect the genetic material of hematopoietic cells of mice from damaging effects of acute total body irradiation. The objective of this study was to the potential radioprotective effects of pharmacological doses of melatonin in total body irradiated rat's peripheral blood cells. Forty adult rats were divided into 4 equal groups. Group 1 received no melatonin or irradiation (control group), while group 2 received only melatonin (5 mg/kg, i.p.). Group 3 received only total body irradiation (RT) by 5 Gy of gamma irradiation only and group 4 received RT plus melatonin (5 mg/kg, i.p., 30 min before RT). An hour and a half following RT, blood samples were taken. Leukocytes and thrombocytes number and hemoglobin levels were measured in all groups. Five mg/kg dose of melatonin significantly protected leukocytes and as well as thrombocytes number against y irradiation. There were no significant differences between Hb levels. Our results suggest that melatonin administration prior to irradiation prevented radiation damage on peripheral blood cells. Melatonin radioprotection is achieved by its ability as a scavenger for free radicals generated by ionizing radiation and acts probably as a growth factor, especially for granulocytes in bone marrow.

  16. Effect of gamma irradiation on the wear behaviour of human tooth enamel

    PubMed Central

    Qing, Ping; Huang, Shengbin; Gao, ShanShan; Qian, LinMao; Yu, HaiYang

    2015-01-01

    Radiotherapy is a frequently used treatment for oral cancer. Extensive research has been conducted to detect the mechanical properties of dental hard tissues after irradiation at the macroscale. However, little is known about the influence of irradiation on the tribological properties of enamel at the micro- or nanoscale. Therefore, this study aimed to investigate the effect of gamma irradiation on the wear behaviour of human tooth enamel in relation to prism orientation. Nanoscratch tests, surface profilometer and scanning electron microscope (SEM) analysis were used to evaluate the friction behaviour of enamel slabs before and after treatment with identical irradiation procedures. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were performed to analyse the changes in crystallography and chemical composition induced by irradiation. Surface microhardness (SMH) alteration was also evaluated. The results showed that irradiation resulted in different scratch morphologies, friction coefficients and remnant depth and width at different loads. An inferior nanoscratch resistance was observed independent of prism orientation. Moreover, the variation of wear behaviours was closely related to changes in the crystallography, chemical composition and SMH of the enamel. Together, these measures indicated that irradiation had a direct deleterious effect on the wear behaviour of human tooth enamel. PMID:26099692

  17. Effect of gamma irradiation on the wear behaviour of human tooth enamel.

    PubMed

    Qing, Ping; Huang, Shengbin; Gao, ShanShan; Qian, LinMao; Yu, HaiYang

    2015-06-23

    Radiotherapy is a frequently used treatment for oral cancer. Extensive research has been conducted to detect the mechanical properties of dental hard tissues after irradiation at the macroscale. However, little is known about the influence of irradiation on the tribological properties of enamel at the micro- or nanoscale. Therefore, this study aimed to investigate the effect of gamma irradiation on the wear behaviour of human tooth enamel in relation to prism orientation. Nanoscratch tests, surface profilometer and scanning electron microscope (SEM) analysis were used to evaluate the friction behaviour of enamel slabs before and after treatment with identical irradiation procedures. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were performed to analyse the changes in crystallography and chemical composition induced by irradiation. Surface microhardness (SMH) alteration was also evaluated. The results showed that irradiation resulted in different scratch morphologies, friction coefficients and remnant depth and width at different loads. An inferior nanoscratch resistance was observed independent of prism orientation. Moreover, the variation of wear behaviours was closely related to changes in the crystallography, chemical composition and SMH of the enamel. Together, these measures indicated that irradiation had a direct deleterious effect on the wear behaviour of human tooth enamel.

  18. Stimulus aspects of aversive controls: long-term effects of suppression procedures1

    PubMed Central

    Hoffman, Howard S.; Selekman, Warren; Fleshler, Morton

    1966-01-01

    Five years ago, pigeons trained to peck a key for food were periodically presented with a 1000 cps tone which ended with electrical shock. They were then tested for the stimulus generalization of conditioned suppression. After an interruption of 2.5 yr, another series of generalization tests showed no loss of suppression. The present study was conducted 1.5 yr later to retest the effect of an extended interruption on retention of suppression. It was found, again, that suppression did not decline over time. The present paper, which summarizes the earlier data and reports the most recent findings, provides an overview of the extended behavioral consequences of the original aversive procedures administered five years ago. PMID:5970388

  19. Effects of Normothermic Conditioned Microwave Irradiation on Cultured Cells Using an Irradiation System with Semiconductor Oscillator and Thermo-regulatory Applicator

    PubMed Central

    Asano, Mamiko; Sakaguchi, Minoru; Tanaka, Satoshi; Kashimura, Keiichiro; Mitani, Tomohiko; Kawase, Masaya; Matsumura, Hitoshi; Yamaguchi, Takako; Fujita, Yoshikazu; Tabuse, Katsuyoshi

    2017-01-01

    We investigated the effects of microwave irradiation under normothermic conditions on cultured cells. For this study, we developed an irradiation system constituted with semiconductor microwave oscillator (2.45 GHz) and thermos-regulatory applicator, which could irradiate microwaves at varied output powers to maintain the temperature of cultured cells at 37 °C. Seven out of eight types of cultured cells were killed by microwave irradiation, where four were not affected by thermal treatment at 42.5 °C. Since the dielectric properties such as ε’, ε” and tanδ showed similar values at 2.45 GHz among cell types and media, the degree of microwave energy absorbed by cells might be almost the same among cell types. Thus, the vulnerability of cells to microwave irradiation might be different among cell types. In HL-60 cells, which were the most sensitive to microwave irradiation, the viability decreased as irradiation time and irradiation output increased; accordingly, the decrease in viability was correlated to an increase in total joule. However, when a high or low amount of joules per minute was supplied, the correlation between cellular viability and total joules became relatively weak. It is hypothesized that kinds of cancer cells are efficiently killed by respective specific output of microwave under normothermic cellular conditions. PMID:28145466

  20. Effects of irradiation on the mechanical behavior of twined SiC nanowires

    SciTech Connect

    Jin Enze; Niu Lisha; Lin Enqiang; Duan Zheng

    2013-03-14

    Irradiation is known to bring new features in one-dimensional nano materials. In this study, we used molecular dynamics simulations to investigate the irradiation effects on twined SiC nanowires. Defects tend to accumulate from outside toward inside of the twined SiC nanowires with increasing irradiation dose, leading to a transition from brittle to ductile failure under tensile load. Atomic chains are formed in the ductile failure process. The first-principles calculations show that most of the atomic chains are metallic.

  1. Low-temperature irradiation effects on tensile and Charpy properties of low-activation ferritic steels

    NASA Astrophysics Data System (ADS)

    Shiba, Kiyoyuki; Hishinuma, Akimichi

    2000-12-01

    Tensile and Charpy properties of low-activation ferritic steel, F82H irradiated up to 0.8 dpa at low temperature below 300°C were investigated. The helium effect on these properties was also investigated using the boron isotope doping method. Neutron irradiation increased yield stress accompanied with ductility loss, and it also shifted the ductile-to-brittle transition temperature (DBTT) from -50°C to 0°C. Boron-doped F82H showed larger degradation in DBTT and ductility than boron-free F82H, while they had the same yield stress before and after irradiation.

  2. Irradiation and fumigation effects on flavor, aroma and composition of grapefruit products

    SciTech Connect

    Moshonas, M.G.; Shaw, P.E.

    1982-05-01

    Effects were evaluated on grapefruit treated to meet quarantine restrictions against Caribbean fruit fly infestation. Differences were found in flavor of fresh sections, fresh juice, and aroma of peel oil when obtained from fruit irradiated with x-rays, as compared with products from nonirradiated fruit. Flavor differences were found in all pasteurized juices from fruit irradiated at 50-60 krad. Vitamin C levels were significantly lower in juice from most irradiated fruit. Flavor differences were found in fresh and pasteurized juice from fruit treated with methyl bromide, and in pasteurized juice from fruit treated with ethylene dibromide. Aroma differences were found in peel oil from fruit treated with phosphine.

  3. Effects of Gamma Irradiation on Optical Properties of Colloidal Nano-crystals

    SciTech Connect

    Withers, Nathan J.; Sankar, Krishnaprasad; Akins, Brian A.; Memon, Tosifa A.; Smolyakov, Gennady A.; Osinski, Marek; Gu, Jiangjiang; Gu, Tingyi; Bowers, Shin T. |; Greenberg, Melisa R. |; Busch, Robert D.

    2008-07-01

    The effects of {sup 137}Cs gamma irradiation on photoluminescence properties, such as spectra, light output, and lifetime, of several types of colloidal nano-crystals have been investigated. Irradiation-induced damage testing was performed on CdSe/ZnS, LaF{sub 3}:Eu, LaF{sub 3}:Ce, ZnO, and PbI{sub 2} nano-crystals synthesized on a Schlenk line using appropriate solvents and precursors. Optical degradation of the nano-crystals was evaluated based on the measured dependence of their photoluminescence intensity on the irradiation dose. Radiation hardness varies significantly between various nano-crystalline material systems. (authors)

  4. Effect of gamma irradiation on curcuminoids and volatile oils of fresh turmeric ( Curcuma longa)

    NASA Astrophysics Data System (ADS)

    Dhanya, R.; Mishra, B. B.; Khaleel, K. M.

    2011-11-01

    In our earlier study a radiation dose of 5 kGy was reported to be suitable for microbial decontamination and shelf life extension of fresh turmeric ( Curcuma longa), while maintaining its quality attributes. In continuation of that work, the effect of gamma radiation on curcuminoids and volatile oil constituents in fresh turmeric was studied. Fresh peeled turmeric rhizomes were gamma irradiated at doses of 1, 3 and 5 kGy. Curcuminoid content and volatile oils were analyzed by reverse phase HPLC and GC-MS, respectively. The curcuminoid content was slightly increased by gamma irradiation. No statistically significant changes were observed due to irradiation in majority of the volatile oil constituents.

  5. Irradiation effects in oxide dispersion strengthened (ODS) Ni-base alloys for Gen. IV nuclear reactors

    NASA Astrophysics Data System (ADS)

    Oono, Naoko; Ukai, Shigeharu; Kondo, Sosuke; Hashitomi, Okinobu; Kimura, Akihiko

    2015-10-01

    Oxide particle dispersion strengthened (ODS) Ni-base alloys are irradiated by using simulation technique (Fe/He dual-ion irradiation) to investigate the reliability to Gen. IV high-temperature reactors. The fine oxide particles with less than 10 nm in average size and approximately 8.0 × 1022 m-3 in number density remained after 101 dpa irradiation. The tiny helium bubbles were inside grains, not at grain-boundaries; it is advantageous effect of oxide particles which trap the helium atoms at the particle-matrix interface. Ni-base ODS alloys demonstrated their great ability to overcome He embrittlement.

  6. Irradiation effect of polarization direction and intensity of semiconductor laser on injured peripheral nerve

    NASA Astrophysics Data System (ADS)

    Guo-Xin, Xiong; Lei-lei, Xiong

    2016-08-01

    To investigate the irradiation effect of polarization direction and the intensity of a semiconductor laser on the injured peripheral nerve in rabbits, the model of the injured common peroneal nerve was established, the L5,6 spinal segments of the rabbits were irradiated, a uniform rotating polarizer was placed at the laser output which made the polarization direction and intensity of the output laser change according to the 80 Hz cosine law. The experimental results show that irradiating the spinal segment of injured nerves in rabbits with this changeable semiconductor laser can significantly promote the regeneration of injured peripheral nerves and the function recovery.

  7. Effect of irradiation spectrum on the microstructural evolution in ceramic insulators

    SciTech Connect

    Zinkle, S.J.

    1995-04-01

    The objective of this study is to determine and examine the effect of variations in the ionizing and displacive radiation environments on the microstructure of oxide ceramic insulators. Cross section transmission electron microscopy has been used to investigate the microstructure of MgAl{sub 2}O{sub 4} (spinel) and Al{sub 2}O{sub 3} (alumina) following irradiation with ions of varying mass and energy at room temperature and 650{degree}C. These results clearly indicate that light ion and electron irradiations produce microstructures which are not representative of the microstructure that would form in these ceramics during fission or fusion neutron irradiation.

  8. An observed effect of ultraviolet radiation emitted from beta-irradiated HaCaT cells upon non-beta-irradiated bystander cells.

    PubMed

    Le, Michelle; McNeill, Fiona E; Seymour, Colin; Rainbow, Andrew J; Mothersill, Carmel E

    2015-03-01

    Previous research has shown that beta radiation can induce ultraviolet (UV) photon emission in human keratinocyte cells. Spectral analysis using a filter-based method in the ultraviolet range demonstrated that the strongest externally measureable photon emission was induced by beta radiation in the UVA range. In the current study, the potential biological implications of this UV photon emission from beta-irradiated cells were investigated. HaCaT human keratinocyte cells were irradiated with tritium ((3)H) and the photon emission induced was concurrently measured at the strongest externally measurable wavelength, 340 ± 5 nm, using a combination filter-photomultiplier tube system. Unirradiated reporter HaCaT cell cultures were also placed directly above (3)H-irradiated cells so that they would receive the induced secondary photons emitted from beta-irradiated cells, and the clonogenic survival in reporter cells was then assessed. Maximum photon emission (1207.04 ± 107.65 counts per second) was observed during irradiation of 2,000 cells/cm(2) with (3)H and the maximum reporter cell death (23.2 ± 0.9% reduction in survival) was observed under the same conditions. The measured photon emission from beta-irradiated cells and reporter cell death were strongly correlated (r = 0.977, P < 0.01). Placement of a polyethylene terephthalate filter, designed to eliminate >90% of UV wavelengths below 390 nm, between the directly irradiated and reporter cell layers was effective in nearly abolishing both 340 nm photon detection and reporter cell death in treated groups. Concurrent treatment of reporter cells with lomefloxacin during exposure to the secondary photons resulted in significantly increased cell killing, indicating a potential synergistic effect, while melanin treatment resulted in decreased reporter cell killing regardless of irradiation. These results suggest that secondary photons in the UV spectral range induced by beta irradiation play a role in inducing a

  9. [Effect of lactobacillus and bifidobacteria preparations on the intestinal microflora of mice irradiated with gamma quanta].

    PubMed

    Korshunov, V M; Kissina, E V; Ikonnikova, T B; Mal'tsev, V N; Goncharova, G I

    1980-06-01

    Lactobacilli (strain B12G) and bifidobacteria (strain 75-41), administered orally in a dose of 5 x 10 cells to CBA mice on days 1, 3, 5 and 10 after irradiation with gamma quanta in a dose of 700 rad, restored the "eubiosis" of the intestinal tract, specifically suppressing opportunistic bacteria and facilitating the normalization of the quantitative and qualitative correlation between microbial associations constituting the obligatory intestinal flora. For one thing, the preparations of lactobacilli and bifidobacteria, used for treatment, restored the amount of lactobacilli in the intestinal tract of the irradiated animals to the level, characteristic of the intact animals; for another, these preparations prevented the dissemination of Escherichia, Proteus, Enterococcus in the small intestine and considerably decreased the amount of these microorganisms, as well as Clostridium, in the large intestine.

  10. Low doses of gamma-irradiation induce an early bystander effect in zebrafish cells which is sufficient to radioprotect cells.

    PubMed

    Pereira, Sandrine; Malard, Véronique; Ravanat, Jean-Luc; Davin, Anne-Hélène; Armengaud, Jean; Foray, Nicolas; Adam-Guillermin, Christelle

    2014-01-01

    The term "bystander effect" is used to describe an effect in which cells that have not been exposed to radiation are affected by irradiated cells though various intracellular signaling mechanisms. In this study we analyzed the kinetics and mechanisms of bystander effect and radioadaptation in embryonic zebrafish cells (ZF4) exposed to chronic low dose of gamma rays. ZF4 cells were irradiated for 4 hours with total doses of gamma irradiation ranging from 0.01-0.1 Gy. In two experimental conditions, the transfer of irradiated cells or culture medium from irradiated cells results in the occurrence of DNA double strand breaks in non-irradiated cells (assessed by the number of γ-H2AX foci) that are repaired at 24 hours post-irradiation whatever the dose. At low total irradiation doses the bystander effect observed does not affect DNA repair mechanisms in targeted and bystander cells. An increase in global methylation of ZF4 cells was observed in irradiated cells and bystander cells compared to control cells. We observed that pre-irradiated cells which are then irradiated for a second time with the same doses contained significantly less γ-H2AX foci than in 24 h gamma-irradiated control cells. We also showed that bystander cells that have been in contact with the pre-irradiated cells and then irradiated alone present less γ-H2AX foci compared to the control cells. This radioadaptation effect is significantly more pronounced at the highest doses. To determine the factors involved in the early events of the bystander effect, we performed an extensive comparative proteomic study of the ZF4 secretomes upon irradiation. In the experimental conditions assayed here, we showed that the early events of bystander effect are probably not due to the secretion of specific proteins neither the oxidation of these secreted proteins. These results suggest that early bystander effect may be due probably to a combination of multiple factors.

  11. The effects of oxide evolution on mechanical properties in proton- and neutron-irradiated Fe-9%Cr ODS steel

    NASA Astrophysics Data System (ADS)

    Swenson, M. J.; Dolph, C. K.; Wharry, J. P.

    2016-10-01

    The objective of this study is to evaluate the effect of irradiation on the strengthening mechanisms of a model Fe-9%Cr oxide dispersion strengthened steel. The alloy was irradiated with protons or neutrons to a dose of 3 displacements per atoms at 500 °C. Nanoindentation was used to measure strengthening due to irradiation, with neutron irradiation causing a greater increase in yield strength than proton irradiation. The irradiated microstructures were characterized using transmission electron microscopy and atom probe tomography (APT). Cluster analysis reveals solute migration from the Y-Ti-O-rich nanoclusters to the surrounding matrix after both irradiations, though the effect is more pronounced in the neutron-irradiated specimen. Because the dissolved oxygen atoms occupy interstitial sites in the iron matrix, they contribute significantly to solid solution strengthening. The dispersed barrier hardening model relates microstructure evolution to the change in yield strength, but is only accurate if solid solution contributions to strengthening are considered simultaneously.

  12. Effect of low dose electron beam irradiation on the alteration layer formed during nuclear glass leaching

    NASA Astrophysics Data System (ADS)

    Mougnaud, S.; Tribet, M.; Renault, J.-P.; Jollivet, P.; Panczer, G.; Charpentier, T.; Jégou, C.

    2016-12-01

    This investigation concerns borosilicate glass leaching mechanisms and the evolution of alteration layer under electron beam irradiation. A simple glass doped with rare earth elements was selected in order to access mechanistic and structural information and better evaluate the effects of irradiation. It was fully leached in initially pure water at 90 °C and at high glass surface area to solution volume ratio (S/V = 20 000 m-1) in static conditions. Under these conditions, the system quickly reaches the residual alteration rate regime. A small particle size fraction (2-5 μm) was sampled in order to obtain a fairly homogeneous altered material enabling the use of bulk characterization methods. External irradiations with 10 MeV electrons up to a dose of 10 MGy were performed either before or after leaching, to investigate respectively the effect of initial glass irradiation on its alteration behavior and the irradiation stability of the alteration layer. Glass dissolution rate was analyzed by regular leachate samplings and the alteration layer structure was characterized by Raman, luminescence (continuous or time-resolved), and 29Si MAS NMR and EPR spectroscopy. It was shown that the small initial glass evolutions under irradiation did not induce any modification of the leaching kinetic nor of the structure of the alteration layer. The alteration process seemed to "smooth over" the created defects. Otherwise, the alteration layer and initial glass appeared to have different behaviors under irradiation. No Eu3+ reduction was detected in the alteration layer after irradiation and the defect creation efficiency was much lower than for initial glass. This can possibly be explained by the protective role of pore water contained in the altered material (∼20%). Moreover, a slight depolymerization of the silicon network of the altered glass under irradiation with electrons was evidenced, whereas in the initial glass it typically repolymerizes.

  13. Effects of gamma irradiation on physicochemical properties, antioxidant and microbial activities of sour cherry juice

    NASA Astrophysics Data System (ADS)

    Arjeh, Edris; Barzegar, Mohsen; Ali Sahari, Mohammad

    2015-09-01

    Recently, due to the beneficial effects of bioactive compounds, demand for minimally processed fruits and fruit juices has increased rapidly in the world. In this study, sour cherry juice (SCJ) was exposed to gamma irradiation at 0.0, 0.5, 1.5, 3.0, 4.5, and 6.0 kGy and then stored at 4 °C for 60 days. Total soluble solids (TSS), total acidity (TA), color, total phenolic content (TPC), total monomeric anthocyanin content (TMC), antioxidant activity, organic acid profile, and microbial analysis were evaluated at regular intervals during the storage. Results indicated that irradiation did not have any significant effect on TSS, while level of TA increased significantly at the dose of 6 kGy (p<0.05). Furthermore, irradiation treatment and storage time led to a significant increase in L* and b* values and a decrease in a* values. Total monomeric anthocyanin content of the irradiated SCJ was lower than that of the non-irradiated one (24% at 3.0 kGy) and also changed toward a more negative direction during the storage (63% at 3.0 kGy for 60 days). There was a significant decrease in the antioxidant activity (DPPH radical scavenging and FRAP assay) in both irradiated and stored SCJs. After irradiation (0-6 kGy), the results showed that the concentration of malic and oxalic acid significantly increased; but, the concentration of ascorbic, citric, fumaric, and succinic acids significantly decreased. Gamma irradiation with doses of ≥3 kGy resulted in overall reduction in microbial loads. Based on the results obtained from the changes of physicochemical properties, antioxidant activity, and microbial analysis, irradiation of SCJ at doses of higher than 3.0 kGy is not recommended.

  14. Radio-protective effects of melatonin against irradiation-induced oxidative damage in rat peripheral blood.

    PubMed

    Shirazi, Alireza; Mihandoost, Ehsan; Mohseni, Mehran; Ghazi-Khansari, Mahmoud; Rabie Mahdavi, Seied

    2013-01-01

    During radiotherapy, ionizing irradiation interacts with biological systems to produce free radicals, which attacks various cellular components. The hematopoietic system is well-known to be radiosensitive and its damage may be life-threatening. Melatonin synergistically acts as an immunostimulator and antioxidant. In this study we used a total of 120 rats with 20 rats in each group. Group 1 did not receive melatonin or irradiation (Control group), Group 2 received only 10 mg/kg melatonin (Mel group), Group 3 exposed to dose of 2 Gy irradiation (2 Gy Rad group), Group 4 exposed to 8 Gy irradiation (8 Gy Rad group), Group 5 received 2 Gy irradiation plus 10 mg/kg melatonin (Mel +2 Gy Rad group) and Group 6 received 8 Gy irradiation plus 10 mg/kg melatonin (Mel+8 Gy Rad group). Following exposure to radiation, five rats from each group were sacrificed at 4, 24, 48 and 72 h. Exposure to different doses of irradiation resulted in a dose-dependent decline in the antioxidant enzymes activity and lymphocyte count (LC) and an increase in the nitric oxide (NO) levels of the serum. Pre-treatment with melatonin (10 mg/kg) ameliorates harmful effects of 2 and 8 Gy irradiation by increasing lymphocyte count(LC) as well as antioxidant enzymes activity and decreasing NO levels at all time-points. In conclusion 10 mg/kg melatonin is likely to be a threshold concentration for significant protection against lower dose of 2 Gy gamma irradiation compared to higher dose of 8 Gy. Therefore, it seems that radio-protective effects of melatonin are dose-dependent.

  15. Effect of syngeneic marrow injection upon recovery in sub- and near-lethally irradiated mice

    SciTech Connect

    Boggs, S.S.; Boggs, D.R.; Patrene, K.D.

    1989-06-01

    Mice were given sub-lethal (200-600 cGy) or near-lethal (800 cGy) whole body irradiation and the effect of injecting syngeneic marrow on subsequent hematopoietic recovery was studied. Marrow cell injection enhanced erythropoietic recovery after sub-lethal irradiation as reflected in hematocrit values and rate of appearance of /sup 59/Fe-labeled red cells in blood. However, this enhanced erythropoiesis was only seen in the spleen, and /sup 59/Fe uptake in marrow was reduced. When the irradiation dose was kept constant and the marrow dose increased from 10(5) to 10(6) to 10(7) cells, there was a somewhat erratic increase in spleen /sup 59/Fe and a decrease in marrow /sup 59/Fe uptake. When marrow cell number was kept constant and the dose of irradiation was increased from 200 to 400 to 600 to 800 cGy, there was an exponential increase in spleen /sup 59/Fe uptake but the marrow /sup 59/Fe uptake changed from depressed after lower doses to increased after 800 cGy. Cell injection after sub-lethal irradiation did not increase or decrease granulocytopoiesis. Injection of irradiated marrow cells also reduced marrow erythropoiesis and this was evident after both sub- and near-lethal irradiation. However, injection of irradiated cells did not increase splenic erythropoiesis. Following splenectomy, the depressed marrow erythropoiesis attending injection of viable cells was virtually eliminated but no increase was seen. These data suggest that the injection of autologous or syngeneic marrow may not be effective as a means of accelerating hematopoietic recovery after irradiation unless near-lethal or lethal dose have been received.

  16. Effects of prenatal irradiation on the development of cerebral cortex and corpus callosum of the mouse

    SciTech Connect

    Schmidt, S.L.; Lent, R.

    1987-10-08

    Defects of the cerebral cortex and corpus callosum of mice subjected prenatally to gamma irradiation were evaluated as a function of dose and of embryonic age at irradiation. Pregnant mice were exposed to a gamma source at 16, 17, and 19 days of gestation (E16, E17, and E19, respectively), with total doses of 2 Gy and 3 Gy, in order to produce brain defects on their progeny. At 60 postnatal days, the brains of the offspring were analyzed qualitatively and quantitatively and compared with those of nonirradiated animals. Mice irradiated at E16 were all acallosal. Those that were exposed to 2 Gy displayed an aberrant longitudinal bundle typical of other acallosals, but this was not the case in those irradiated with 3 Gy. The corpus callosum of animals irradiated at E17 with 3 Gy was pronouncedly hypotrophic, but milder effects were observed in the other groups. Quantitative analysis confirmed a dependence of callosal midsagittal area upon dose and age at irradiation, and, in addition, indicated an interaction between these variables. The neocortex of irradiated animals was hypotrophic: layers II-III were much more affected than layer V, and this was more affected than layer VI. Quantitative analysis indicated that this effect also depended on dose and age at irradiation and that it was due to a loss of cortical neurons. Furthermore, a positive correlation was found between the number of neurons within layers II-III, and V and the midsagittal area of the corpus callosum. Ectopic neurons were found in the white matter and in layer I of animals irradiated at E16 and E17, indicating that fetal exposure to ionizing radiation interfered with the migration of cortical neuroblasts.

  17. Self-Irradiation Effects on 99Mo Reagents and Products

    SciTech Connect

    Carson, S.D.; Garcia, M.J.; McDonald, M.J.; Simpson, R.L.; Tallant, D.R.

    1998-10-07

    produced in 1996 and shipped to pharmaceutical houses for evaluation of compatibility with oxime solution used to precipitate `?vfo as the oxime complex is both air and light-sensitive, and containing a black precipitate that forms during shipment, presumably as a result of self- irradiation. Addition of sodium hypochlorite to the product solution prior to shipment prevents precipitate formation, indicating the precipitate is a reduced form of `%lo. to remove any precipitate. Duplicate aliquots of the filtered samples were titrated to a phenolphthalein irradiation and afler standing at room temperature for 86.4 hours. Precipitates were washed to a FTIR analysis of the white precipitate showed it to be alpha benzoin oxime. Since the basic After 86.4 hours, no precipitate had formed in bottles containing sodium hypochlorite. Black precipitate had formed in all bottles that did not contain sodium hypochlorite after 14.4 hours. The precipitate appeared to initially form on the surface of the HDPE sample bottles and Black precipitate was first noticed in sample set 1 after 28.8 hrs' irradiation. No visible sample containing precipitate was kept at room temperature in the original bottle. Precipitate in sample sets 2 and 3. Since no precipitate formed in these bottles, this was equivalent to duplicate samples. Once the precipitate in the 20-mL aliquots that had been set aside had returned to sample sets 1 through 3 and the samples with redissolved precipitate all experienced an average decrease in base strength of 0.013 meq mL-l. Sample 1-C had a decrease of 0.004 meq mL-l and sample 1-D had returned to the initial value of 0.198 meq mL-l. Raman spectra for the black precipitate from samples l-C, 1-D and supplemental sample set 1 Fig. 2. Raman spectra of the black precipitate formed in 9%40 product solutions after 28.8,43.2, 72 and 86.4 hours of `oCo irradiation in Sandia's Gamma Irradiation Facility. increase with time, as seen in the titration of 1-C and 1-D samples

  18. Photo-annealing effect of gamma-irradiated erbium-doped fibre by femtosecond pulsed laser

    NASA Astrophysics Data System (ADS)

    Hsiung Chang, Sheng; Liu, Ren-Young; Lin, Chu-En; Chou, Fong-In; Tai, Chao-Yi; Chen, Chii-Chang

    2013-12-01

    In this work, a photo-annealing effect of gamma-irradiated erbium-doped glass fibre is investigated. Two commercial erbium-doped fibres (EDFs) with different doping concentrations were sealed inside a chamber with a cobalt-60 gamma source for 6 h to give an accumulated dose of 3.18 kGy. A tunable femtosecond pulsed laser with a repetition rate of 80 MHz was then used to pump EDF to generate 1550 nm fluorescence and green up-conversion emission, resulting in the annealing effect of the gamma-irradiated EDF. The fluorescence power of gamma-irradiated EDF with a moderate level of doping was almost returned to the initial state by photo-annealing, unlike that of a heavily doped EDF. This finding may facilitate the development of anti-irradiated superfluorescence fibre source for space navigation.

  19. Effects of curcumin and capsaicin irradiated with visible light on murine oral mucosa.

    PubMed

    Okada, Norihisa; Muraoka, Eitoku; Fujisawa, Seiichiro; Machino, Mamoru

    2012-01-01

    The purpose of this study was to evaluate the histopathological effects of curcumin and capsaicin, with or without visible light (VL) irradiation for 5 min, on the oral mucous membrane in mice. Capsaicin-treated, but not curcumin-treated, buccal epithelium exhibited slight tissue damage; VL irradiation caused excessive tissue damage, particularly when combined with the former treatment. The TdT-mediated dUTP-biotin nick end-labeling (TUNEL) method demonstrated that both capsaicin and curcumin induced apoptosis, with the apoptotic effect of capsaicin appearing at an early stage of application. VL irradiation increased the number of apoptotic cells, particularly those upon in the capsaicin-treated area. Capsaicin and curcumin acted as photosensitizers exposure to VL, in the presence of oxygen. Curcumin and capsaicin with VL irradiation could thus be used for photodynamic therapy in the clinical setting, especially in precancerous oral diseases.

  20. He and H irradiation effects on the nanoindentation hardness of CLAM steel

    NASA Astrophysics Data System (ADS)

    Jiang, Siben; Peng, Lei; Ge, Hongen; Huang, Qunying; Xin, Jingping; Zhao, Ziqiang

    2014-12-01

    In this study, He and H ion irradiation induced hardening behavior of China Low Activation Martensitic (CLAM) steel was investigated, and the influence of Si on irradiation hardening was also examined. CLAM steel with different Si contents, Heat 0912 and Heat 0408D, were irradiated with single He (He concentration range from 0 to 2150 appm) ion beam and He/H dual ion beams. Then nanoindentation tests were applied to evaluate the ion irradiation induced hardening effect. The result of Heat 0912 showed hardening effect would be more serious with higher He concentration, and the trend saturated when He concentration reach 1000 appm. Comparing the result of Heat 0912 and Heat 0408D, higher Si content might improve the resistance to hardening.

  1. Evaluation of the effects of paederus beetle extract and gamma irradiation on HeLa cells

    PubMed Central

    Samani, Fariba; Monfared, Ali Shabestani; Zabihi, Ebrahim; Khafri, Soraya; Karimi, Maesoumeh; Akhavan Niaki, Haleh

    2014-01-01

    Objective(s): Cervical cancer is a malignancy that is the second most common cause of death from cancer in women throughout the world. Paederus beetle (Paederus fuscipes) extract (PBE), contains bioactive compounds such as pederine which has cytotoxic properties and blocks DNA and protein synthesis at very low concentrations. In this investigation we tried to determine the effects co-treatment with PBE and gamma irradiation on HeLa cells. Materials and Methods: The viability of the cells was measured by two methods: MTT and Colony assay. Results: We found that supplementing gamma irradiation therapy with PBE does not increase cell death and it might even interfere with its cytotoxicty at the concentrations below 0.1 ng/ml and the viability for irradiation vs irradiation + PBE was 37%: 60%. Conclusion: This finding might be due to radioprotective effects of the very low doses of PBE against gamma radiation. PMID:24904724

  2. Comparative Effects of Gamma Irradiation and Ozone Treatment on Hygienic Quality of Korean Red Ginseng Powder

    NASA Astrophysics Data System (ADS)

    Byun, Myung-Woo; Yook, Hong-Sun; Kang, Il-Jun; Chung, Cha-Kwon; Kwon, Joong-Ho; Choi, Kang-Ju

    1998-06-01

    For the purpose of improving hygienic quality of Korean red ginseng powder, the comparative effects of gamma irradiation and ozone treatment on the microbial and physicochemical properties were investigated. Gamma irradiation at 7.5 kGy resulted in sterilization of total aerobic bacteria, molds and coliforms below detective levels, while ozone treatment for 8 hours up to 18 ppm did not sufficiently eliminate the microorganisms of the red ginseng powder. Physicochemical properties including compositions of the red ginseng saponin (ginsenosides) and fatty acids, pH and hydrogen doanting activity were not significantly changed by gamma irradiation, whereas, ozone treatment caused significant changes in fatty acid compositions, TBA value, pH, acidity and hydrogen donating activity. The results from this study led us to conclude that gamma irradiation was more effective than ozone treatment both for the improvement of hygienic quality and for the maintenance of physicochemical quality of red ginseng powder.

  3. Effect of gamma-ray irradiation on the dewaterability of waste activated sludge

    NASA Astrophysics Data System (ADS)

    Wu, Yuqi; Jiang, Yinghe; Ke, Guojun; Liu, Yingjiu

    2017-01-01

    The effect of gamma-ray irradiation on waste activated sludge (WAS) dewaterability was investigated with irradiation doses of 0-15 kGy. Time to filter (TTF50), specific resistance of filtration (SRF) and water content of sludge cake were measured to evaluate sludge dewaterability. Soluble chemical oxygen demand (SCOD), soluble extracellular polymeric substances (EPS) concentration and sludge particle size were determined to explain changes in sludge dewaterability. The optimal irradiation dose to obtain the maximum dewaterability characteristics was 1-4 kGy, which generated sludge with optimal disintegration (1.5-4.0%), soluble EPS concentration (590-750 mg/L) and particle size distribution (100-115 μm diameter). The combination of irradiation and cationic polyacrylamide (CPAM) addition exhibited minimal synergistic effect on increasing sludge dewatering rate compared with CPAM conditioning alone.

  4. Apraclonidine effects on ocular responses to YAG laser irradiation to the rabbit iris

    SciTech Connect

    Sugiyama, K.; Kitazawa, Y.; Kawai, K. )

    1990-04-01

    Apraclonidine (p-aminoclonidine) ophthalmic solution effectively reduces the rise in intraocular pressure (IOP) following anterior segment laser surgery. We tested the effect of topical 0.5% apraclonidine on intraocular pressure and on protein and prostaglandin (PG) E2 concentrations in aqueous humor following Q-switched Nd:YAG laser irradiation to the iris of albino rabbits, at an energy level of 2 to 200 mJ. IOP was measured prior to and for 24 hr after irradiation. Aqueous humor was withdrawn before and 1 hr after laser irradiation for determining protein (Lowry method) and PGE2 (radioimmunoassay). Four to seven rabbits were used for each experiment. The increase in IOP and protein concentration following laser irradiation was demonstrated to be dependent on the amount of laser energy. Apraclonidine completely abolished the IOP rise, and significantly reduced the elevation of protein content. Apraclonidine failed to affect the increase in PGE2.

  5. Effects of irradiation on protein electrophoretic properties, water absorption and cooking quality of lentils.

    PubMed

    Celik, Süeda; Yalçin, Erkan; Başman, Arzu; Köksel, Hamit

    2004-12-01

    Effects of gamma irradiation at doses of 1 kGy, 5 kGy, and 10 kGy on water absorption properties, cooking quality and electrophoretic patterns of insoluble proteins of red and green lentil samples were investigated. The densitometric analysis indicated that the effects of irradiation on sodium dodecyl sulfate-polycrylamide gel electrophoresis patterns of red and green lentil proteins were not significant. Generally, a 1 kGy irradiation dose did not significantly affect the water absorption properties of the lentil samples while significant increases were observed at the 5 kGy level. The dry and wet cooking times were found to be significantly decreased, as the irradiation level increased in all red and green lentil samples.

  6. [Effect of infrared laser irradiation on the arterial blood pressure in liquidators of the accident at the Chernobyl power plant].

    PubMed

    Korkushko, O O

    2003-01-01

    Liquidators of Tchernobyl accident with discirculatory post-irradiation encephalopathy were treated with infra-red lazer irradiation together with a half doze of pharmacological agents usually used. Infra-red lazer irradiation has been shown to result in a significant reduce in the arterial pressure level, so it can be effective in correcting the disturbances in haemodynamics.

  7. Synergetic effect of freeze-drying and gamma irradiation on the mechanical properties of human cancellous bone.

    PubMed

    Cornu, Olivier; Boquet, Jérome; Nonclercq, Olivier; Docquier, Pierre-Louis; Van Tomme, John; Delloye, Christian; Banse, Xavier

    2011-11-01

    Freeze-drying and irradiation are common process used by tissue banks to preserve and sterilize bone allografts. Freeze dried irradiated bone is known to be more brittle. Whether bone brittleness is due to irradiation alone, temperature during irradiation or to a synergetic effect of the freeze-drying-irradiation process was not yet assessed. Using a left-right femoral head symmetry model, 822 compression tests were performed to assess the influence of sequences of a 25 kGy irradiation with and without freeze-drying compared to the unprocessed counterpart. Irradiation of frozen bone did not cause any significant reduction in ultimate strength, stiffness and work to failure. The addition of the freeze-drying process before or after irradiation resulted in a mean drop of 35 and 31% in ultimate strength, 14 and 37% in stiffness and 46 and 37% in work to failure. Unlike irradiation at room temperature, irradiation under dry ice of solvent-detergent treated bone seemed to have no detrimental effect on mechanical properties of cancellous bone. Freeze-drying bone without irradiation had no influence on mechanical parameters, but the addition of irradiation to the freeze-drying step or the reverse sequence showed a detrimental effect and supports the idea of a negative synergetic effect of both procedures. These findings may have important implications for bone banking.

  8. Effect of γ-irradiation in the keeping quality of Nigerian onion cultivars

    NASA Astrophysics Data System (ADS)

    Agbaji, A. S.; Ogbadu, G. H.; Van Amstel, H.

    Onion of variety Ds × Ws'78 and Ds'79 harvested 14 days prior to the experiment were treated with 5, 8 and 15 krad doses of γ-irradiation from a 60Co γ-irradiator. Bulbs were stored in a well ventilated room at ambient temperature (20-25°C) and RH 20-82% in vegetable mesh bags on wooden shelves for 7 months. Onions were weekly investigated for sprouting and rotting. Chemical analyses were carried out monthly for dry matter, flavour, ascorbic acid, reducing sugar and protein. In comparison, a local method of storage was carried out. Irradiation dose of 5-15 krad completely inhibited sprouting throughout the whole storage period. Irradiated bulbs however, showed a higher tendency to rot. In comparison with the control, irradiation did not have any significant effect on dry matter, flavour component and ascorbic acid but the protein content was significantly lower in the irradiated bulbs. The compositional differences found between irradiated and untreated onions seem to be of no nutritional or organoleptic significance. Almost 100% loss was recorded for local storage trial.

  9. Effect of Initial Heat Treatment on DBTT of F82H Steel Irradiated by Neutrons

    SciTech Connect

    Wakai, E.; Ando, M.; Matsukawa, S.; Taguchi, T.; Yamamoto, T.; Tomita, H.; Takada, F.

    2005-05-15

    The dependence of ductile-brittle transition temperature (DBTT) on tempering time and temperature was examined for a martensitic steel F82H irradiated at 150 and 250 deg. C to a neutron dose of 1.9 dpa in the JMTR. The heat treatment was performed at 750 and 780 deg. C for 0.5 h after the normalizing at 1040 deg. C for 0.5 h. The tempering time at 750 deg. C was varied from 0.5 to 10 h. 1/3CVN specimens were used in this study, and the absorbed energies in the impact tests were measured as a function of temperature. DBTT of F82H steels irradiated at 250 deg. C to 1.9 dpa was ranged from -23 to 25 deg. C, and DBTT of F82H steels irradiated at 150 deg. C to 1.9 dpa was ranged from 0 to 15 deg. C. DBTT of F82H steels irradiated at 250 deg. C depended strongly on temperature and time of tempering, and it tended to decrease with increasing yield stress. The effect of tempering conditions on DBTT was smaller in the specimens irradiated at 150 deg. C. DBTT due to irradiation in the F82H steels irradiated at 250 deg. C tended to decrease with increasing time and temperature of tempering.

  10. Effect of nickel content on the neutron irradiation embrittlement of Ni-Mo-Cr steels

    NASA Astrophysics Data System (ADS)

    Lee, Chang-Hoon; Kasada, R.; Kimura, A.; Lee, Bong-Sang; Suh, Dong-Woo; Lee, Hu-Chul

    2013-11-01

    The influence of nickel on the neutron irradiation embrittlement of Ni-Mo-Cr reactor pressure vessel (RPV) steels was investigated using alloys containing nickel in the range of 0.9-3.5 wt%. In all investigated alloys, the neutron irradiation with two dose conditions of 4.5 × 1019 neutron/cm2 at 290 °C and 9.0 × 1019 neutron/cm2 at 290 °C, respectively, increased the hardness and ductile-to-brittle transition temperature (DBTT). However, the increases of the hardness and DBTT resulting from the neutron irradiation were primarily affected by the irradiation dose that is closely related to the generation of irradiation defects, but not by the nickel content. In addition, a linear relationship between the changes in the hardness and DBTT subjected to the irradiation was confirmed. These results demonstrate that increasing the nickel content up to 3.5 wt% does not have a harmful effect on the irradiation embrittlement of Ni-Mo-Cr reactor pressure vessel (RPV) steels.

  11. Continuous gamma-irradiation of rats: dose-rate effect on loss and recovery of spermatogenesis.

    PubMed

    Pinon-Lataillade, G; Maas, J

    1985-07-01

    Male Sprague Dawley rats were continuously irradiated at a dose-rate of either 5 or 7 cGy/day, up to a total dose of 900 cGy. Changes in spermatogenesis with irradiation and the recovery of the testis during 33 weeks after irradiation were studied. No clear dose-rate effect with testicular weight occurred. During the irradiation time, increased dose and dose-rate induced a decrease in A spermatogonia and preleptotene spermatocyte number. In our experimental conditions germ cell production did not plateau, as shown by the increasing number of tubular cross sections devoid of germ cells beyond 500 cGy. The recovery of seminiferous epithelium occurred essentially within nine weeks. It was not dose-rate dependent and was still incomplete after 33 weeks. This lack of recovery might be due to limited compensatory division ability of the stem cells. Clusters of Sertoli cells were observed in the lumen of the seminiferous tubules; impaired function of these cells could also prevent the complete recovery of the seminiferous epithelium. By 16 weeks after the end of irradiation 67% of 5 cGy/day irradiated rats and 34% of 7 cGy/day irradiated rats recovered fertility.

  12. An animal model of prophylactic cranial irradiation: Histologic effects at acute, early and delayed stages

    SciTech Connect

    Mildenberger, M.; Beach, T.G.; McGeer, E.G.; Ludgate, C.M. )

    1990-05-01

    Wistar rats (body wt. 200 g) were subjected to a fractionated course of radiation similar to that used in prophylactic brain irradiation for small cell carcinoma of the lung (2000 cGy in 5 fractions over 5 days with {sup 60}Co). Effects of this regimen were assessed by histologic examination of brain sections at 1 week, 1 month and 6 months post-irradiation. With conventional stains there were no apparent differences between control and irradiated brains at any of the post-irradiation intervals. Immunohistochemistry for neurotransmitter synthetic enzymes tyrosine hydroxylase and glutamate decarboxylase, as well as histochemistry for acetylcholinesterase, failed to uncover any changes in the irradiated animals. Immunohistochemistry for glial fibrillary acidic protein, an astrocyte marker, also showed no differences in the irradiated groups. However, an antibody against a major histocompatibility complex, class II antigen (OX-6) revealed a microglial response in grey and white matter beginning at 1 month and increasing up to the 6 month post-irradiation interval. The neuroanatomical basis for this microglial response was suggested by the results of silver stains for nerve axons, which revealed axonal loss in striatal white matter bundles in a pattern implicating vascular insufficiency.

  13. Effect of gamma irradiation on linear low density polyethylene/magnesium hydroxide/sepiolite composite

    NASA Astrophysics Data System (ADS)

    Shafiq, Muhammad; Yasin, Tariq

    2012-01-01

    Radiation crosslinking is generally used to improve the thermo-mechanical properties of the composites. A study has been carried out to investigate the effect of gamma radiation on the thermo-mechanical properties of linear low density polyethylene containing magnesium hydroxide (MH) and sepiolite (SP) as non-halogenated flame retardant additives. The developed composites are irradiated at different doses upto maximum of 150 kGy. Infrared spectra of the irradiated composites reveal the reduction in the intensity of O-H band with increase in the absorbed doses, thus indicates a distinct structural change in MH at higher doses. The thermogravimetric analysis results of unirradiated and composites irradiated at low doses (≤75 kGy) show two steps weight loss, which is changed to single step at higher doses with lower thermal stability. The melting temperature ( Tm) and crystallization temperature ( Tc) of irradiated composites are lowered with irradiation whereas Vicat softening temperature (VST) is increased. The increasing trend in gel content with increase in the absorbed dose confirms the presence of crosslinked network. The mechanical properties, results show significant improvement in the modulus of irradiated composites. The results also confirm that MH gradually loses its OH functionality with irradiation.

  14. Age-related effects of X-ray irradiation on mouse hippocampus

    PubMed Central

    Casciati, Arianna; Dobos, Katalin; Antonelli, Francesca; Benedek, Anett; Kempf, Stefan J.; Bellés, Montserrat; Balogh, Andrea; Tanori, Mirella; Heredia, Luis; Atkinson, Michael J.; von Toerne, Christine; Azimzadeh, Omid; Saran, Anna; Sáfrány, Geza; Benotmane, Mohammed A.; Linares-Vidal, M. Victoria; Tapio, Soile; Lumniczky, Katalin; Pazzaglia, Simonetta

    2016-01-01

    Therapeutic irradiation of pediatric and adult patients can profoundly affect adult neurogenesis, and cognitive impairment manifests as a deficit in hippocampal-dependent functions. Age plays a major role in susceptibility to radiation, and younger children are at higher risk of cognitive decay when compared to adults. Cranial irradiation affects hippocampal neurogenesis by induction of DNA damage in neural progenitors, through the disruption of the neurogenic microenvironment, and defective integration of newborn neurons into the neuronal network. Our goal here was to assess cellular and molecular alterations induced by cranial X-ray exposure to low/moderate doses (0.1 and 2 Gy) in the hippocampus of mice irradiated at the postnatal ages of day 10 or week 10, as well as the dependency of these phenomena on age at irradiation. To this aim, changes in the cellular composition of the dentate gyrus, mitochondrial functionality, proteomic profile in the hippocampus, as well as cognitive performance were evaluated by a multidisciplinary approach. Our results suggest the induction of specific alterations in hippocampal neurogenesis, microvascular density and mitochondrial functions, depending on age at irradiation. A better understanding of how irradiation impairs hippocampal neurogenesis at low and moderate doses is crucial to minimize adverse effects of therapeutic irradiation, contributing also to radiation safety regulations. PMID:27057631

  15. Effect of semiconductor GaAs laser irradiation on pain perception in mice

    SciTech Connect

    Zarkovic, N.; Manev, H.; Pericic, D.; Skala, K.; Jurin, M.; Persin, A.; Kubovic, M.

    1989-01-01

    The influence of subacute exposure (11 exposures within 16 days) of mice to the low power (GaAs) semiconductive laser-stimulated irradiation on pain perception was investigated. The pain perception was determined by the latency of foot-licking or jumping from the surface of a 53 degrees C hot plate. Repeated hot-plate testing resulted in shortening of latencies in both sham- and laser-irradiated mice. Laser treatment (wavelength, 905 nm; frequency, 256 Hz; irradiation time, 50 sec; pulse duration, 100 nsec; distance, 3 cm; peak irradiance, 50 W/cm2 in irradiated area; and total exposure, 0.41 mJ/cm2) induced further shortening of latencies, suggesting its stimulatory influence on pain perception. Administration of morphine (20 mg/kg) prolonged the latency of response to the hot plate in both sham- and laser-irradiated mice. This prolongation tended to be lesser in laser-irradiated animals. Further investigations are required to elucidate the mechanism of the observed effect of laser.

  16. Effects of low intensity laser irradiation during healing of infected skin lesions in the rat

    NASA Astrophysics Data System (ADS)

    Nussbaum, Ethne L.; Lilge, Lothar; Mazzulli, Tony; Pritzker, Kenneth P.

    2006-02-01

    Purpose: To determine the effect of low intensity laser therapy (LILT) on healing of infected skin wounds in the rat. Methods: Wounds on the dorsum of Sprague-Dawley rats (14 per group) were inoculated or sham-inoculated with P. aeruginosa. Wounds were irradiated or sham-irradiated three times weekly from Day 1-19 using 635nm or 808nm diode lasers at radiant exposure of 1 or 20 J/cm2 delivered in continuous wave (CW) or at an intensity modulation frequency of 3800Hz. Wound area and bacterial growth were evaluated three times weekly. Results: CW 808 nm (1 and 20 J/cm2) irradiation generally delayed healing in acute wounds. However, from Day 10 onwards CW 808 nm (1 J/cm2 and 20 J/cm2) and 808 nm 3800 Hz (1 J/cm2) irradiation improved healing in inoculated wounds. Healing in acute wounds improved using 635 nm irradiation at low radiant exposure (1 J/cm2); however, using 635 nm irradiation at high radiant exposure (20 J/cm2) delayed healing. Bacterial balance in wounds was significantly altered using 635 nm (20 J/cm2) and CW 808 nm irradiation (1 and 20 J/cm2). Conclusion: Clearing wounds of normal flora was not associated with improved healing. Proliferation of staphylococcal species in wounds was associated with delayed healing.

  17. Prenatal exposure to gamma/neutron irradiation: Sensorimotor alterations and paradoxical effects on learning

    SciTech Connect

    Di Cicco, D.; Antal, S.; Ammassari-Teule, M. )

    1991-01-01

    The effects of prenatal exposure on gamma/neutron radiations (0.5 Gy at about the 18th day of fetal life) were studied in a hybrid strain of mice (DBA/Cne males x C57BL/Cne females). During ontogeny, measurements of sensorimotor reflexes revealed in prenatally irradiated mice (1) a delay in sensorial development, (2) deficits in tests involving body motor control, and (3) a reduction of both motility and locomotor activity scores. In adulthood, the behaviour of prenatally irradiated and control mice was examined in the open field test and in reactivity to novelty. Moreover, their learning performance was compared in several situations. The results show that, in the open field test, only rearings were more frequent in irradiated mice. In the presence of a novel object, significant sex x treatment interactions were observed since ambulation and leaning against the novel object increased in irradiated females but decreased in irradiated males. Finally, when submitted to different learning tasks, irradiated mice were impaired in the radial maze, but paradoxically exhibited higher avoidance scores than control mice, possibly because of their low pain thresholds. Taken together, these observations indicate that late prenatal gamma/neutron irradiation induces long lasting alterations at the sensorimotor level which, in turn, can influence learning abilities of adult mice.

  18. Effects of salts and temperatures on post-irradiation growth of Penicillium exposed to ultraviolet

    SciTech Connect

    Valdez, R.; Siegel, B.Z.; Siegel, S.M.

    1981-01-01

    The growth of Penicillium notatum colonies after uv irradiation of dried mycelium or spores was studied in relation to post-irradiation temperature and salt environment. Dried mycelium and spores behaved differently with respect to sensitivity to temperature, salts and uv, especially the latter. Threshold inhibitory doses for spores were modified markedly either at 4 C or in magnesium and calcium chlorides. It is suggested that these temperature and salt effects are related to prevention of photochemical membrane damage.

  19. Expertise, Working Memory and Articulatory Suppression Effect: Their Relation with Simultaneous Interpreting Performance

    PubMed Central

    Injoque-Ricle, Irene; Barreyro, Juan Pablo; Formoso, Jesica; Jaichenco, Virginia I.

    2015-01-01

    Simultaneous interpreting is a complex bilingual verbal activity that involves the auditory perception of an oral communication and the production of a coherent discourse. One of the cognitive functions underlying simultaneous interpreting is working memory. The aim of this work was to study the relationship between expertise, working memory capacity and articulatory suppression effect, and the ability to perform simultaneous interpreting. For this purpose, four working memory tasks and one simultaneous interpreting task were administered to thirty Spanish-speaking professional English interpreters. Results showed that simultaneous interpreting ability might be supported by the working memory´s capacity to store or process information, but also by the ability of the interpreter to cope with the articulatory suppression effect. We conclude that interpreters may have or develop resources to support the effect caused by articulatory suppression. PMID:26207153

  20. Suppressive effect of sinomenine combined with 5-fluorouracil on colon carcinoma cell growth.

    PubMed

    Zhang, Ji-Xiang; Yang, Zi-Rong; Wu, Dan-Dan; Song, Jia; Guo, Xu-Feng; Wang, Jing; Dong, Wei-Guo

    2014-01-01

    It is reported that sinomenine (SIN) and 5-fluorouracil (5-FU) both are effective for colon cancer, but their cooperative suppressive effects and toxicity remain to be clarified in detail. This study aimed to determine suppressive effects and toxicity of sinomenine (SIN) plus 5-fluorouracil (5-FU) on LoVo colon carcinoma cells in vitro and in vivo. CCK-8, Hoechst 33258 staining and an annexin V-FITC/PI apoptosis kit were used to detect suppressive effects. Western blotting was applied to investigate the essential mechanism underlying SIN and 5-FU-induced apoptosis. SIN or 5-FU or both were injected into nude mice, and then suppressive effects and side effects were observed. SIN plus 5-FU apparently inhibited the proliferation of LoVo cells and induced apoptosis. Moreover the united effects were stronger than individually (p<0.05). The results of annexin V-FITC /PI staining and Hoechst 33258 staining showed that the percentage of apoptotic cells induced by SIN and 5-FU combined or alone was significantly higher than the control group (p<0.05). Expression of Bax and Bcl-2 was up-regulated and down-regulated respectively. SIN or 5-FU significantly inhibited effects on the volume of tumour xenografts and their combined suppressive effects were stronger (p<0.05). No obvious side effects were observed. It was apparent that the united effects of SIN and 5-FU on the growth of colorectal carcinoma LoVo cells in vitro and in vivo were superior to those using them individually, and it did not markedly increase the side effects of chemotherapy.

  1. Effects of electron beam irradiation on the structural properties of polylactic acid/polyethylene blends

    NASA Astrophysics Data System (ADS)

    Bee, Soo-Tueen; Ratnam, C. T.; Sin, Lee Tin; Tee, Tiam-Ting; Wong, Wai-Kien; Lee, Jiuun-Xiang; Rahmat, A. R.

    2014-09-01

    The purpose of this research was to investigate the effects of electron beam irradiation on the properties of polylactic acid (PLA) and low density polyethylene (LDPE) blends. The PLA were compounded with 20-80% LDPE and were exposed to electron beam irradiation dosages of 20-120 kGy. The results from gel content and X-ray diffraction analyses showed that the addition of LDPE to PLA effectively increased the gel content and crystallinity. However, an increasing percentage of LDPE reduced the tensile strength and Young's modulus of the PLA/LDPE samples due to the lower intermolecular bonding of LDPE than of PLA. Moreover, an increase in irradiation dosages gradually decreased the mechanical properties of low-LDPE PLA/LDPE. In contrast, the increasing irradiation dosage enhanced the mechanical properties of higher-LDPE PLA/LDPE. These results indicate that higher amounts of LDPE effectively react with the release of free radicals within the amorphous phase if the blends are subjected to irradiation. The higher amounts of free radicals induce the formation of three-dimensional cross-linked networks in the polymer matrix and thus increase the gel content. The irradiation-induced cross-linking in PLA/LDPE samples improves the mechanical properties and crystallinity by promoting a structural rearrangement of the polymer matrix into a highly ordered structure.

  2. Effects of irradiated polypropylene compatibilizer on the properties of short carbon fiber reinforced polypropylene composites

    NASA Astrophysics Data System (ADS)

    Gamze Karsli, Nevin; Aytac, Ayse; Akbulut, Meshude; Deniz, Veli; Güven, Olgun

    2013-03-01

    In this study, the effects of irradiated polypropylene (PP) compatibilizer addition into PP matrix on the interfacial adhesion between the carbon fiber (CF) and PP matrix were investigated. Unirradiated and irradiated PPs were blended, and two types of carbon fibers; unsized (surface treated) and sized, were used for composites preparation. In order to characterize the physical and morphological properties of all CF reinforced composites prepared, tensile tests, differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and Positron annihilation lifetime spectroscopy (PALS) were performed. The strong compatibilizing effects of irradiated PP on the mechanical properties of composites were noticed. It has been found that breaking strength values were increased up to 30%. The compatibilizing effect of irradiated PP was also confirmed with SEM micrographs and PALS. It has been seen that blending PP matrix with irradiated PP improved the interfacial adhesion between the carbon fiber and matrix materials. The melting point temperatures of composites were not changed significantly for all composites. The results showed that irradiated PP as a compatibilizer together with unsized carbon fiber in place of sized carbon fiber can be used in order to improve the mechanical properties of carbon fiber reinforced PP composites.

  3. Neutron irradiation effects on the ductile-brittle transition of ferritic/martensitic steels

    SciTech Connect

    Klueh, R.L.; Alexander, D.J.

    1997-06-01

    Ferritic/martensitic steels such as the conventional 9Cr-1MoVNb (Fe-9Cr-1Mo-0.25V-0.06Nb-0.1C) and 12Cr-1MoVW (Fe-12Cr-1Mo-0.25V-0.5W-0.5Ni-0.2C) steels have been considered potential structural materials for future fusion power plants. The major obstacle to their use is embrittlement caused by neutron irradiation. Observations on this irradiation embrittlement will be reviewed. Below 425-450{degrees}C, neutron irradiation hardens the steels. Hardening reduces ductility, but the major effect is an increase in the ductile-brittle transition temperature (DBTT) and a decrease in the upper-shelf energy, as measured by a Charpy impact test. After irradiation, DBTT values can increase to well above room temperature, thus increasing the chances of brittle rather than ductile fracture. In addition to irradiation hardening, neutrons from the fusion reaction will produce large amounts of helium in the steels used to construct fusion power plant components. Tests to simulate the fusion environment indicate that helium can also affect the toughness. Steels are being developed for fusion applications that have a low DBTT prior to irradiation and then show only a small shift after irradiation. A martensitic 9Cr-2WVTa (nominally Fe-9Cr-2W-0.25V-0.07Ta-0.1C) steel had a much lower DBTT than the conventional 9Cr-1MoVNb steel prior to neutron irradiation and showed a much smaller increase in DBTT after irradiation. 27 refs., 5 figs., 1 tab.

  4. Modification of PVC/ENR blend by electron beam irradiation: effect of crosslinking agents

    NASA Astrophysics Data System (ADS)

    Ratnam, C. T.; Zaman, K.

    1999-05-01

    In order to improve the mechanical properties of PVC/ENR blends, they were irradiated by using a 3.0 MeV electron beam machine with doses ranging from 20 to 200 kGy. Changes in mechanical properties of the blends with increasing irradiation dose were investigated. In an attempt to maximize the beneficial effect of irradiation, the influence of multifunctional acrylates (MFA) such as TMPTA, HDDA and EHA on the 70/30 PVC/ENR blend was investigated. The properties studied include hardness, gel fraction, tensile strength, elongation at break and glass transition temperature. The results revealed that all mechanical properties increased with increasing irradiation dose with exception of elongation at break. The enhancement in blend properties was further improved by addition of MFA. This is attributed to the increase in crosslink density. The steady increase in gel fraction with irradiation dose and the shifting of the irradiation those towards a lower value to achieve 70% gel fraction upon addition of MFA has provided evidence for significant increase in crosslink density. Among the MFA employed in this studies, TMPTA was found to render highest mechanical properties to the blend with irradiation. Thus, TMPTA can be useful as an efficient crosslink enhancer to PVC/ENR blends. Results from Fourier transform infrared spectroscopy (FTIR) indicated radiation-induced crosslinks formed in PVC/ENR blends sensitized by TMPTA. The single glass transition temperature obtained confirms that the blend remains miscible upon irradiation with the presence of TMPTA. The changes in blend properties upon irradiation with the addition of acrylated polyurethene (PU) oligomer are also presented in this paper.

  5. Cerebrovascular and metabolic effects on the rat brain of focal Nd:YAG laser irradiation

    SciTech Connect

    Kiessling, M.; Herchenhan, E.; Eggert, H.R. )

    1990-12-01

    To investigate the effects of focal neodymium:yttrium-aluminum-garnet (Nd:YAG) laser irradiation (lambda = 1060 nm) on regional cerebral blood flow, cerebral protein synthesis, and blood-brain barrier permeability, the parietal brain surface of 44 rats was irradiated with a focused laser beam at a constant output energy of 30 J. Survival times ranged from 5 minutes to 48 hours. Laser irradiation immediately caused well-defined cortical coagulation necrosis. Within 5 minutes after unilateral irradiation, 14C-iodoantipyrine autoradiographs demonstrated severely reduced blood flow to the irradiation site and perilesional neocortex, but a distinct reactive hyperemia in all other areas of the forebrain. Apart from a persistent ischemic focus in the vicinity of the cortical coagulation necrosis, blood flow alterations in remote areas of the brain subsided within 3 hours after irradiation. Autoradiographic assessment of 3H-tyrosine incorporation into brain proteins revealed rapid onset and prolonged duration of protein synthesis inhibition in perifocal morphologically intact cortical and subcortical structures. Impairment of amino acid incorporation proved to be completely reversible within 48 hours. Immunoautoradiographic visualization of extravasated plasma proteins using 3H-labeled rabbit anti-rat immunoglobulins-showed that, up to 1 hour after irradiation, immunoreactive proteins were confined to the neocortex at the irradiation site. At 4 hours, vasogenic edema was present in the vicinity of the irradiation site and the subcortical white matter, and, at later stages (16 to 36 hours), also extended into the contralateral hemisphere. Although this was followed by a gradual decrease in labeling intensity, resolution of edema was still not complete after 48 hours.

  6. Effects of mindfulness, reappraisal, and suppression on sad mood and cognitive resources.

    PubMed

    Keng, Shian-Ling; Tan, Elysia Li Yan; Eisenlohr-Moul, Tory A; Smoski, Moria J

    2017-04-01

    The present study investigated the relative effects of mindfulness, reappraisal and suppression in reducing sadness, and the extent to which implementation of these strategies affects cognitive resources in a laboratory context. A total of 171 Singaporean undergraduate participants were randomly assigned to receive brief training in mindfulness, reappraisal, or suppression prior to undergoing a sad mood induction. Individual adherence to Asian cultural values was assessed as a potential moderator of strategy effectiveness. Participants rated their mood and completed a Color-Word Stroop task before and after mood regulation instructions. Analyses using multi-level modelling showed that the suppression condition caused less robust declines in sadness over time compared to mindfulness. There was also a nonsignificant trend in which mindfulness was associated with greater sadness recovery compared to reappraisal. Suppression resulted in lower average sadness compared to mindfulness among those high on Asian cultural values, but not those low on Asian cultural values. Both mindfulness and reappraisal buffered against increases in Stroop interference from pre-to post-regulation compared to suppression. The findings highlight the advantage of mindfulness as a strategy effective not only in the regulation of sad mood, but also in the preservation of cognitive resources in the context of mood regulation.

  7. The effect of in vivo and in vitro irradiation (25 Gy) on the subsequent in vitro growth of satellite cells

    NASA Technical Reports Server (NTRS)

    Mozdziak, P. E.; Schultz, E.; Cassens, R. G.

    1996-01-01

    The effect of in vivo and in vitro irradiation on subsequent satellite cell growth, in vitro, was investigated to ascertain the ability of a 25 Gy dose to inhibit satellite cell proliferation. Satellite cells were isolated from the left (irradiated) and right (non-irradiated) Pectoralis thoracicus of two-week-old tom turkeys 16 h (n=3) and seven weeks (n=2) after the left Pectoralis thoracicus had been irradiated (25 Gy). Satellite cells isolated from the irradiated and non-irradiated muscles exhibited similar (P>0.10) in vitro proliferation indicating that a population of satellite cells survived an in vivo dose of 25 Gy. In additional experiments, satellite cell cultures derived from tom turkey Pectoralis thoracicus were irradiated (25 Gy) in vitro. The number of satellite cells did not (P>0.05) increase in irradiated cultures for 134 h following irradiation, while satellite cells in non-irradiated cultures proliferated (P<0.05) over this time. At later time periods, satellite cell number increased (P<0.05) in irradiated cultures indicating that a population of satellite cells survived irradiation. The results of these in vitro experiments suggest that a 25 Gy dose of irradiation does not abolish satellite cell divisions in the turkey Pectoralis thoracicus.

  8. A Review of Irradiation Effects on Organic-Matrix Insulation

    SciTech Connect

    Simon, N.J.

    1993-06-01

    This review assesses the data base on epoxy and polyimide matrix insulation to determine whether organic electric insulation systems can be used in the toroidal field (TF) magnets of next generation fusion devices such as ITER* and TPX*. Owing to the difficulties of testing insulation under fusion reactor conditions, there is a considerable mismatch between the ITER requirements and the data that are currently available. For example, nearly all of the high-dose (5 x 10{sup 7} to 10{sup 8} Gy) data obtained on epoxy and polyimide matrix insulation employed gamma irradiation, electron irradiation, or reactor irradiation with a fast neutron fluence far below 10{sup 23}/m{sup 2}, the fluence expected for the insulation at the TF magnets, as set forth in ITER conceptual design documents. Also, the neutron spectrum did not contain a very high energy (E {ge} 5 MeV) component. Such data underestimate the actual damage that would be obtained with the neutron fluence and spectrum expected at a TF magnet. Experiments on a polyimide (Kapton) indicate that gamma or electron doses or mixed gamma and neutron reactor doses would have to be downgraded by a factor of up to ten to simulate fusion neutron doses. Even when neutrons did constitute a significant portion of the total dose, B-containing E-glass reinforcement was often used; therefore, excess damage from the {sup 10}B + n {yields} {sup 7}Li + {alpha} reaction occurred near the glass-epoxy interface. This problem can easily be avoided by substituting B-free glass (R, S, or T types).

  9. Effects of electron beam irradiation of cellulose acetate cigarette filters

    NASA Astrophysics Data System (ADS)

    Czayka, M.; Fisch, M.

    2012-07-01

    A method to reduce the molecular weight of cellulose acetate used in cigarette filters by using electron beam irradiation is demonstrated. Radiation levels easily obtained with commercially available electron accelerators result in a decrease in average molecular weight of about six-times with no embrittlement, or significant change in the elastic behavior of the filter. Since a first step in the biodegradation of cigarette filters is reduction in the filter material's molecular weight this invention has the potential to allow the production of significantly faster degrading filters.

  10. Effect of gamma irradiation on electrical properties of Cu nanowires

    SciTech Connect

    Rana, Pallavi Gehlawat, Devender Chauhan, R. P.

    2014-04-24

    Metallic nanowires are of great interest due to their unique electrical, optical, chemical and magnetic properties. Characterization and explanations of electronic properties of nanowires are extremely important due to their potential applications in the field of nanoelectronics and optoelectronics. In the present study, we synthesized the copper nanowires of different diameters (80nm, 100nm and 200nm) and exposed them with gamma rays of 100 KGy and 150 KGy doses. The I-V characteristics of different diameter of Cu nanowires before and after the irradiation were recorded.

  11. Assessment of Antiradiation Drug Effectiveness to Fission Neutron Irradiation.

    DTIC Science & Technology

    1983-09-01

    SIGDESTRD SEP 83 UNLSSFEE DMD1 EEiC-hhhE/G6/1 ENhhhEEohmhmhE EhEEomhEmhohhhE EEshmhhhEohhhI EhEohEEEEohhhE EhhhhEEEEEImo = 111112. 1111I 25 1. 1.-6 MICROCOPY...WR 151327 80 25 . Spleen Colony Survival: Neutrons - WR 168643 82 - .. 8 LIST OF TABLES TABLE PAGE 1. Salient Drug Information 18 2. Neutron Lethality...microcolony assay was used to determine crypt survival in the intestine ( 25 ). Three and one- half days following irradiation, a section of the jejunem 1-2 cm

  12. Chemical effects in C 60 irradiation of polymers

    NASA Astrophysics Data System (ADS)

    Möllers, R.; Tuccitto, N.; Torrisi, V.; Niehuis, E.; Licciardello, A.

    2006-07-01

    The C 60 erosion behaviour of poly(methyl)methacrylate (PMMA), poly(α-methyl)styrene (PAMS) and polystyrene (PS) has been studied at various temperatures and compared with that under Ga + irradiation. Strong variations of erosion yields are observed, indicating that chemical degradation mechanisms are operating. In particular, our results suggest that fast depolymerization mechanisms are important in leaving the surface of the sputter crater virtually undamaged. Since such mechanisms are connected with the chemical nature of the polymer, the possibility of performing molecular depth profiling of polymers with C 60 appears to depend strongly on the chemical nature of the system under study.

  13. Suppressive effects of androgens on the immune system.

    PubMed

    Trigunaite, Abhishek; Dimo, Joana; Jørgensen, Trine N

    2015-04-01

    Sex-based disparities in immune responses are well known phenomena. The two most important factors accounting for the sex-bias in immunity are genetics and sex hormones. Effects of female sex hormones, estrogen and progesterone are well established, however the role of testosterone is not completely understood. Evidence from unrelated studies points to an immunosuppressive role of testosterone on different components of the immune system, but the underlying molecular mechanisms remains unknown. In this review we evaluate the effect of testosterone on key cellular components of innate and adaptive immunity. Specifically, we highlight the importance of testosterone in down-regulating the systemic immune response by cell type specific effects in the context of immunological disorders. Further studies are required to elucidate the molecular mechanisms of testosterone-induced immunosuppression, leading the way to the identification of novel therapeutic targets for immune disorders.

  14. Food intake suppressant effect of baclofen in rats.

    PubMed

    Zarrindast, M R; Hosseini-Nia, T; Allah-Maddadi, S

    1989-01-01

    1. Baclofen given intraperitoneally (i.p.) to rats caused a dose-dependent decrease in food intake. 2. Bicuculline or picrotoxin (GABAA-antagonist) and methergoline (5-HT antagonist) decreased the anorectic effect of baclofen. 3. Pimozide (dopamine receptor blocker), phenoxybenzamine and propranolol (alpha and beta adrenergic blockers) did not diminish the baclofen effect, but even increased the anorexia induced by the drug. 4. It can be postulated that, at least partially, GABAA receptor mechanism, GABA-5HT receptor complex and/or 5-HT mechanism may be involved in baclofen induced anorexia.

  15. Effect of Nutrient Starvation under High Irradiance on Lipid and Starch Accumulation in Chlorella fusca (Chlorophyta).

    PubMed

    Jerez, Celia G; Malapascua, José R; Sergejevová, Magda; Figueroa, Félix L; Masojídek

    2016-02-01

    The effect of nitrogen and sulphur limitation under high irradiance (PAR) was studied in the green microalga Chlorella fusca (Chlorophyta) in order to follow lipid and/or starch accumulation. Growth, biomass composition and the changes in photosynthetic activity (in vivo chlorophyll a fluorescence) were followed in the trials. The full nutrient culture showed high biomass production and starch accumulation at Day 1, when photosynthetic activity was high. Gradual deprivation (no nutrients added) became evident when photosynthesis was significantly suppressed (Day 3 onwards), which entailed a decrease of maximum relative electron transport rate (rETRmax) and increase of non-photochemical quenching (NPQ), accompanied by the onset of lipid accumulation and decline in starch content. In N- and S-starved cultures, rETRmax significantly decreased by Day 3, which caused a substantial drop in biomass production, cell number, biovolume and induction of lipid and starch accumulation. High starch content (45-50 % of DW) was found at the initial stage in full nutrient culture and at the stationary phase in nutrient-starved cultures. By the end of the trial, all treatments showed high lipid content (~30 % of DW). The full nutrient culture had higher biomass yield than starved treatments although starch (~0.2 g L(-1) day(-1)) and lipid (~0.15 g L(-1) day(-1) productivities were fairly similar in all the cultures. Our results showed that we could enrich biomass of C. fusca (% DW) in lipids using a two-stage strategy (a nutrient replete stage followed by gradual nutrient limitation) while under either procedure, N- or S-starvation, both high lipid and starch contents could be achieved.

  16. Distractor Detection and Suppression Have a Beneficial Effect on Attentional Blink

    PubMed Central

    Zhao, Jing; Li, Hong; Ding, Cody; Chen, Antao

    2012-01-01

    Background Attentional blink (AB) is a phenomenon that describes the difficulty individuals have in reporting the second of two masked targets if the second target (T2) arrives 200–500 ms after the first target (T1). Recent studies explain the AB from cognitive resources limitation to distractors interference. For example, the temporary loss of control (TLC) hypothesis suggests that the AB is conduced by distractors disrupting the input filter for target processing. The inhibition models suggest that the T1+1 distractor triggers a suppression mechanism which could be beneficial for T1 processing but would suppress T2 at short T1–T2 lags. These models consider that the AB is caused by the appearance of distractors. However, in the present study, two methods were taken to help individuals to detect the distractors more effectively. An attenuated AB deficit was found when the distractors could be excluded or suppressed in time. We consider that under an appropriate condition the distractors detection and suppression have a beneficial effect on attentional blink. Methodology/Principal Findings Two methods were employed to help individuals to detect the distractors more effectively: enlarging the low-level-physical characteristic difference between targets and distractors (Experiment 1) and restricting the sets of distractors (Experiment 2). Attenuated AB deficits were found as using the above manipulations. Conclusions/Significance The present study found when the distractors are detected or identified quickly, they could be effectively suppressed, in order to reduce the interference from the targets and result in a smaller AB deficit. We suggest that the suppression mechanism for distractors have a beneficial effect on AB. PMID:22984558

  17. RF noise suppression using the photodielectric effect in semiconductors

    NASA Technical Reports Server (NTRS)

    Arndt, G. D.

    1969-01-01

    Technique using photodielectric effect of semiconductor in high-Q superconductive cavity gives initial improvement of 2-4 db in signal-to-noise enhancement of conventional RF communication systems. Wide band signal plus noise can be transmitted through a narrow-band cavity due to parametric perturbation of the cavity frequency or phase.

  18. Effect of electron beam irradiation on thermal and mechanical properties of epoxy polymer

    NASA Astrophysics Data System (ADS)

    Nguyen, A. T.; Visakh, P. M.; Nazarenko, O. B.; Chandran, C. S.; Melnikova, T. V.

    2017-01-01

    This study investigates the thermal and mechanical properties of epoxy polymer after exposure to different doses of electron beam irradiation. The epoxy polymer was prepared using epoxy-diane resin ED-20 cured by polyethylenepolyamine. The irradiation of the samples was carried out with doses of 30, 100 and 300 kGy. The effects of doses on thermal and mechanical properties of the epoxy polymer were investigated by the methods of thermal gravimetric analysis, tensile test, and dynamic mechanical analysis. The thermal properties of the epoxy polymer slightly increased after irradiation at the heating in air. The tensile strength and Young’s modulus of the epoxy polymer increased by the action of electron beam up to dose of 100 kGy and then decreased. The elongation at break decreased with increasing the irradiation dose.

  19. Effect of irradiation temperature on void swelling of China Low Activation Martensitic steel (CLAM)

    SciTech Connect

    Zhao Fei; Qiao Jiansheng; Huang Yina; Wan Farong Ohnuki, Soumei

    2008-03-15

    CLAM is one composition of a Reduced Activation Ferritic/Martensitic steel (RAFM), which is being studied in a number of institutes and universities in China. The effect of electron-beam irradiation temperature on irradiation swelling of CLAM was investigated by using a 1250 kV High Voltage Electron Microscope (HVEM). In-situ microstructural observations indicated that voids formed at each experimental temperature - 723 K, 773 K and 823 K. The size and number density of voids increased with increasing irradiation dose at each temperature. The results show that CLAM has good swelling resistance. The maximum void swelling was produced at 723 K; the swelling was about 0.3% when the irradiation damage was 13.8 dpa.

  20. Neutron irradiation effects on the ductile-brittle transition of ferritic/martensitic steels

    SciTech Connect

    Klueh, R.L.; Alexander, D.J.

    1997-08-01

    Ferritic/martensitic steels such as the conventional 9Cr-1MoVNb (Fe-9Cr-1Mo-0.25V-0.06Nb-0.1C) and 12Cr-1MoVW (Fe-12Cr-1Mo-0.25V-0.5W-0.5Ni-0.2C) steels have been considered potential structural materials for future fusion power plants. The major obstacle to their use is embrittlement caused by neutron irradiation. Observations on this irradiation embrittlement is reviewed. Below 425-450{degrees}C, neutron irradiation hardens the steels. Hardening reduces ductility, but the major effect is an increase in the ductile-brittle transition temperature (DBTT) and a decrease in the upper-shelf energy, as measured by a Charpy impact test. After irradiation, DBTT values can increase to well above room temperature, thus increasing the chances of brittle rather than ductile fracture.

  1. Effect of gamma irradiation on nutrient digestibility in SPF mini-pig

    NASA Astrophysics Data System (ADS)

    Lee, Jun-Yeob; Cho, Sung-Back; Kim, Yoo-Yong; Ohh, Sang-Jip

    2011-01-01

    This study was carried out to evaluate the effect of gamma irradiation on nutrient digestibility of either soy-based or milk-based diet for specific pathogen-free (SPF) mini-pigs. Gamma irradiation of the diets was done at dosage of 10 kGy with 60Co whereas autoclaving was executed at 121 °C for 20 min. Apparent crude protein digestibilities of gamma irradiated diets were higher ( p<0.05) than those of autoclaved diets regardless of diet type. Digestibilities of dry matter, gross energy and total carbohydrate in the irradiated diet were higher than those of the autoclaved diet. From the results of nutrient digestibility of mini-pig diets in this study, 10 kGy gamma radiation was suggested as a convenient diet radicidation method that can minimize the decrease in nutrient digestibility on feeding to SPF mini-pigs.

  2. Current understanding of the effects of enviromental and irradiation variables on RPV embrittlement

    SciTech Connect

    Odette, G.R.; Lucas, G.E.; Wirth, B.; Liu, C.L.

    1997-02-01

    Radiation enhanced diffusion at RPV operating temperatures around 290{degrees}C leads to the formation of various ultrafine scale hardening phases, including copper-rich and copper-catalyzed manganese-nickel rich precipitates. In addition, defect cluster or cluster-solute complexes, manifesting a range of thermal stability, develop under irradiation. These features contribute directly to hardening which in turn is related to embrittlement, manifested as shifts in Charpy V-notch transition temperature. Models based on the thermodynamics, kinetics and micromechanics of the embrittlement processes have been developed; these are broadly consistent with experiment and rationalize the highly synergistic effects of most important irradiation (temperature, flux, fluence) and metallurgical (copper, nickel, manganese, phosphorous and heat treatment) variables on both irradiation hardening and recovery during post-irradiation annealing. A number of open questions remain which can be addressed with a hierarchy of new theoretical and experimental tools.

  3. Effect of gas environment and sorbate addition on flavor characteristics of irradiated apple cider during storage.

    PubMed

    Crook, Loretta R; Boylston, Terri D; Glatz, Bonita A

    2004-11-17

    Apple cider, with (0.1%) and without potassium sorbate, was packaged in polystyrene containers and exposed to three different gas environments: oxygen flush, nitrogen flush, and atmospheric air. To evaluate the effects of irradiation (2 kGy) and storage on flavor and microbial quality, these irradiated apple cider samples were compared to a control, unirradiated sample exposed to atmospheric air. Volatile compounds, soluble solids, titratable acidity, and microbiological counts were determined weekly throughout 7 weeks of refrigerated (4 degrees C) storage. Cider irradiated and stored in atmospheric air or nitrogen-flush environments had lower rates of loss for characteristic flavor volatiles compared to unirradiated apple cider and cider irradiated and stored in an oxygen-flush environment. The addition of potassium sorbate to the apple cider resulted in lower counts of yeasts and aerobic microorganisms, reduced fermentation of sugars to organic acids, and improved retention of volatile compounds characteristic of apple cider.

  4. Light induced suppression of Kondo effect at amorphous LaAlO3/SrTiO3 interface

    NASA Astrophysics Data System (ADS)

    Liu, G. Z.; Qiu, J.; Jiang, Y. C.; Zhao, R.; Yao, J. L.; Zhao, M.; Feng, Y.; Gao, J.

    2016-07-01

    We report photoelectric properties of two-dimensional electron gas (2DEG) at an amorphous LaAlO3/SrTiO3 interface. Under visible light illumination (650 nm), an enhancement of electric conductivity is observed over the temperature range from 2 to 300 K. Particularly, a resistance upturn appearing below 25 K, which is further proved to from the Kondo effect, is suppressed by the 650 nm visible light. From the results of light-assisted Hall measurements, light irradiation increases the carrier mobility rather than carrier density in the Kondo regime. It is suggested that light induces the decoherence effect of localized spin states, hence the electron scattering is weakened and the carrier mobility is improved accordingly. Moreover, the enhancement of electrical conductivity by visible light verifies that in-gap states located in the SrTiO3 side of the interface play an important role in the electrical transport of the amorphous SrTiO3-based oxide 2DEG system. Our results provide deeper insight into the photoinduced effects in the 2DEG system, paving the way for the design of optoelectronic devices based on oxides.

  5. Adaptive center determination for effective suppression of ring artifacts in tomography images

    SciTech Connect

    Jha, D. Sørensen, H. O. Dobberschütz, S.; Stipp, S. L. S.; Feidenhans'l, R.

    2014-10-06

    Ring artifacts on tomogram slices hinder image interpretation. They are caused by minor variation in the response from individual elements in a two dimensional (2D) X-ray detector. Polar space decreases the suppression complexity by transforming the rings on the tomogram slice to linear stripes. However, it requires that the center of rings lie at the origin of polar transformation. If this is not the case, all methods employing polar space become ineffective. We developed a method based on Gaussian localization of the ring center in Hough parameter space to assign the origin for the polar transformation. Thus, obtained linear stripes can be effectively suppressed by already existing methods. This effectively suppresses ring artifacts in the data from a variety of experimental setups, sample types and also handles tomograms that are previously cropped. This approach functions automatically, avoids the need for assumptions and preserves fine details, all critical for synchrotron based nanometer resolution tomography.

  6. Effect of γ-irradiation on the volatile compounds of medicinal herb, Paeoniae Radix

    NASA Astrophysics Data System (ADS)

    Shim, Sung-Lye; Hwang, In-Min; Ryu, Keun-Young; Jung, Min-Seok; Seo, Hye-young; Kim, Hee-Yeon; Song, Hyun-Pa; Kim, Jae-Hun; Lee, Ju-Woon; Byun, Myung-Woo; Kwon, Joong-Ho; Kim, Kyong-Su

    2009-07-01

    A study was carried out to find the effect of γ-irradiation on contents of volatile compounds from medicinal herb, Paeoniae Radix ( Paenia albiflora Pallas var. trichocarpa Bunge). The volatile compounds of control, 1, 3, 5 and 10 kGy irradiated samples were extracted by simultaneous steam distillation and extraction (SDE) method and analyzed by gas chromatograph-mass spectrometer. The major volatile compounds were paeonol, ( E)-carveol, ( E, E)-2,4-octadienal, methyl salicylate, myrtanol and eugenol acetate. Volatile compounds belonging to chemical classes of acids, alcohols, aldehydes, esters, hydrocarbons and miscellaneous were identified in all experimental samples. The types of volatile compounds in irradiated samples were similar to those of non-irradiated sample and the concentrations of these compounds differed between treatments. 1,3-Bis (1,1-dimethylethyl)-benzene was identified by using the selected ion monitoring (GC/MS-SIM) mode. The concentration of this compound increased with the increase of irradiation dose level. These results suggest that it could be used as the base data for the effect of γ-irradiation on medicinal herb.

  7. Protective effects of HemoHIM on immune and hematopoietic systems against γ-irradiation.

    PubMed

    Park, Hae-Ran; Jo, Sung-Kee; Jung, Uhee; Yee, Sung-Tae; Kim, Sung-Ho

    2014-02-01

    We examined the effect of HemoHIM on the protective efficacy of hematopoietic stem cells and on the recovery of immune cells against sublethal doses of ionizing radiation. Two-month-old mice were exposed to γ-rays at a dose of 8, 6.5, or 5 Gy for a30-day survival study, endogenous spleen colony formation, or other experiments, respectively. HemoHIM was injected intraperitoneally before and after irradiation. Our results showed that HemoHIM significantly decreased the mortality of sublethally irradiated mice. The HemoHIM administration decreased the apoptosis of bone marrow cells in irradiated mice. On the other hand, HemoHIM increased the formation of endogenous spleen colony in irradiated mice. In irradiated mice, the recovery of total leukocytes in the peripheral blood and lymphocytes in the spleen were enhanced significantly by HemoHIM. Moreover, the function of B cells, T cells, and NK cells regenerated in irradiated mice were significantly improved by the administration of HemoHIM. HemoHIM showed an ideal radioprotector for protecting hematopoietic stem cells and for accelerating the recovery of immune cells. We propose HemoHIM as a beneficial supplement drug during radiotherapy to alleviate adverse radiation-induced effects for cancer patients.

  8. Effect of γ irradiation on the fatty acid composition of soybean and soybean oil.

    PubMed

    Minami, Ikuko; Nakamura, Yoshimasa; Todoriki, Setsuko; Murata, Yoshiyuki

    2012-01-01

    Food irradiation is a form of food processing to extend the shelf life and reduce spoilage of food. We examined the effects of γ radiation on the fatty acid composition, lipid peroxidation level, and antioxidative activity of soybean and soybean oil which both contain a large amount of unsaturated fatty acids. Irradiation at 10 to 80 kGy under aerobic conditions did not markedly change the fatty acid composition of soybean. While 10-kGy irradiation did not markedly affect the fatty acid composition of soybean oil under either aerobic or anaerobic conditions, 40-kGy irradiation considerably altered the fatty acid composition of soybean oil under aerobic conditions, but not under anaerobic conditions. Moreover, 40-kGy irradiation produced a significant amount of trans fatty acids under aerobic conditions, but not under anaerobic conditions. Irradiating soybean oil induced lipid peroxidation and reduced the radical scavenging activity under aerobic conditions, but had no effect under anaerobic conditions. These results indicate that the fatty acid composition of soybean was not markedly affected by radiation at 10 kGy, and that anaerobic conditions reduced the degradation of soybean oil that occurred with high doses of γ radiation.

  9. Evaluating the Effects of Gamma-Irradiation for Decontamination of Medicinal Cannabis

    PubMed Central

    Hazekamp, Arno

    2016-01-01

    In several countries with a National medicinal cannabis program, pharmaceutical regulations specify that herbal cannabis products must adhere to strict safety standards regarding microbial contamination. Treatment by gamma irradiation currently seems the only method available to meet these requirements. We evaluated the effects of irradiation treatment of four different cannabis varieties covering different chemical compositions. Samples were compared before and after standard gamma-irradiation treatment by performing quantitative UPLC analysis of major cannabinoids, as well as qualitative GC analysis of full cannabinoid and terpene profiles. In addition, water content and microscopic appearance of the cannabis flowers was evaluated. This study found that treatment did not cause changes in the content of THC and CBD, generally considered as the most important therapeutically active components of medicinal cannabis. Likewise, the water content and the microscopic structure of the dried cannabis flowers were not altered by standard irradiation protocol in the cannabis varieties studied. The effect of gamma-irradiation was limited to a reduction of some terpenes present in the cannabis, but keeping the terpene profile qualitatively the same. Based on the results presented in this report, gamma irradiation of herbal cannabis remains the recommended method of decontamination, at least until other more generally accepted methods have been developed and validated. PMID:27199751

  10. Effects of PVA, agar contents, and irradiation doses on properties of PVA/ws-chitosan/glycerol hydrogels made by γ-irradiation followed by freeze-thawing

    NASA Astrophysics Data System (ADS)

    Yang, Xiaomin; Zhu, Zhiyong; Liu, Qi; Chen, Xiliang; Ma, Mingwang

    2008-08-01

    Poly(vinyl alcohol) (PVA)/water soluble chitosan (ws-chitosan)/glycerol hydrogels were prepared by γ-irradiation and γ-irradiation followed by freeze-thawing, respectively. The effects of irradiation dose and the contents of PVA and agar on the swelling, rheological, and thermal properties of these hydrogels were investigated. The swelling capacity decreases while the mechanical strength increases with increasing PVA or agar content. Increasing the irradiation dose leads to an increase in chemical crosslinking density but a decrease in physical crosslinking density. Hydrogels made by irradiation followed by freeze-thawing own smaller swelling capacity but larger mechanical strength than those made by pure irradiation. The storage modulus of the former hydrogels decreases above 50 °C and above 70 °C it comes to the same value as that prepared by irradiation. The ordered association of PVA is influenced by both chemical and physical crosslinkings and by the presence of ws-chitosan and glycerol. These hydrogels are high sensitive to pH and ionic strength, indicating that they may be useful in stimuli-responsive drug release system.

  11. Multiscale Modeling of Irradiation effects in Fusion Materials

    SciTech Connect

    Hussein Zbib

    2004-12-23

    The aim of this collaborative research work was to apply predictive, physically based multiscale modeling to improve understanding of the underlying mechanisms of material changes in the fusion environment, with the ultimate objective to aid development of advanced materials. The multiscale modeling methodology involved a hierarchical approach, integrating ab initio electronic structure calculations, molecular dynamics (MD) simulations, kinetic Monte Carlo (KMC), and three dimensional dislocation dynamics (DD) simulations, over the relevant length and time scales to model the fates of defects and solutes (including hydrogen and helium) and thus, predict microstructural evolution in ferritic/martensitic and vanadium based alloys. The main task at WSU was to investigate changes in mechanical properties as a result of the production of a varied population of nanostructural features and to be obtained from three dimensional dislocation dynamics simulation (DD). The initial dislocation structure and microstructure could be obtained from electron microscopy characterization and the appropriate nanostructural features produced during irradiation are introduced from predictions of the multiscale modeling. The dislocation structure was then allowed to evolve under an applied load, taking into account all possible forces and reactions between the dislocations with the radiation induced nanostructure as well as network dislocations. In this manner, quantitative predictions of irradiation hardening would result without the use of empirical constants within the framework of dispersed barrier hardening models.

  12. Early effects of cranial irradiation on hypothalamic-pituitary function

    SciTech Connect

    Lam, K.S.; Tse, V.K.; Wang, C.; Yeung, R.T.; Ma, J.T.; Ho, J.H.

    1987-03-01

    Hypothalamic-pituitary function was studied in 31 patients before and after cranial irradiation for nasopharyngeal carcinoma. The estimated radiotherapy (RT) doses to the hypothalamus and pituitary were 3979 +/- 78 (+/- SD) and 6167 +/- 122 centiGrays, respectively. All patients had normal pituitary function before RT. One year after RT, there was a significant decrease in the integrated serum GH response to insulin-induced hypoglycemia. In the male patients, basal serum FSH significantly increased, while basal serum LH and testosterone did not change. Moreover, in response to LHRH, the integrated FSH response was increased while that of LH was decreased. Such discordant changes in FSH and LH may be explained by a defect in LHRH pulsatile release involving predominantly a decrease in pulse frequency. The peak serum TSH response to TRH became delayed in 28 patients, suggesting a defect in TRH release. Twenty-one patients were reassessed 2 yr after RT. Their mean basal serum T4 and plasma cortisol levels had significantly decreased. Hyperprolactinemia associated with oligomenorrhoea was found in 3 women. Further impairment in the secretion of GH, FSH, LH, TSH, and ACTH had occurred, and 4 patients had hypopituitarism. Thus, progressive impairment in hypothalamic-pituitary function occurs after cranial irradiation and can be demonstrated as early as 1 yr after RT.

  13. Thermal effects in tissues induced by interstitial irradiation of near infrared laser with a cylindrical diffuser

    NASA Astrophysics Data System (ADS)

    Le, Kelvin; Johsi, Chet; Figueroa, Daniel; Goddard, Jessica; Li, Xiaosong; Towner, Rheal A.; Saunders, Debra; Smith, Nataliya; Liu, Hong; Hode, Tomas; Nordquist, Robert E.; Chen, Wei R.

    2011-03-01

    Laser immunotherapy (LIT), using non-invasive laser irradiation, has resulted in promising outcomes in the treatment of late-stage cancer patients. However, the tissue absorption of laser light limits the clinical applications of LIT in patients with dark skin, or with deep tumors. The present study is designed to investigate the thermal effects of interstitial irradiation using an 805-nm laser with a cylindrical diffuser, in order to overcome the limitations of the non-invasive mode of treatment. Cow liver and rat tumors were irradiated using interstitial fiber. The temperature increase was monitored by thermocouples that were inserted into the tissue at different sites around the cylinder fiber. Three-dimensional temperature distribution in target tissues during and after interstitial laser irradiation was also determined by Proton Resonance Frequency. The preliminary results showed that the output power of laser and the optical parameters of the target tissue determined the light distribution in the tissue. The temperature distributions varied in the tissue according to the locations relative to the active tip of the cylindrical diffuser. The temperature increase is strongly related to the laser power and irradiation time. Our results using thermocouples and optical sensors indicated that the PRF method is reliable and accurate for temperature determination. Although the inhomogeneous biological tissues could result in temperature fluctuation, the temperature trend still can be reliable enough for the guidance of interstitial irradiation. While this study provides temperature profiles in tumor tissue during interstitial irradiation, the biological effects of the irradiation remain unclear. Future studies will be needed, particularly in combination with the application of immunostimulant for inducing tumor-specific immune responses in the treatment of metastatic tumors.

  14. Effect of laser soldering irradiation on covalent bonds of pure collagen.

    PubMed

    Constantinescu, Mihai A; Alfieri, Alex; Mihalache, George; Stuker, Florian; Ducray, Angélique; Seiler, Rolf W; Frenz, Martin; Reinert, Michael

    2007-03-01

    Laser tissue welding and soldering is being increasingly used in the clinical setting for defined surgical procedures. The exact induced changes responsible for tensile strength are not yet fully investigated. To further improve the strength of the bonding, a better understanding of the laser impact at the subcellular level is necessary. The goal of this study was to analyze whether the effect of laser irradiation on covalent bonding in pure collagen using irradiances typically applied for tissue soldering. Pure rabbit and equine type I collagen were subjected to laser irradiation. In the first part of the study, rabbit and equine collagen were compared using identical laser and irradiation settings. In the second part of the study, equine collagen was irradiated at increasing laser powers. Changes in covalent bonding were studied indirectly using the sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) technique. Tensile strengths of soldered membranes were measured with a calibrated tensile force gauge. In the first experiment, no differences between the species-specific collagen bands were noted, and no changes in banding were found on SDS-PAGE after laser irradiation. In the second experiment, increasing laser irradiation power showed no effect on collagen banding in SDS-PAGE. Finally, the laser tissue soldering of pure collagen membranes showed virtually no determinable tensile strength. Laser irradiation of pure collagen at typical power settings and exposure times generally used in laser tissue soldering does not induce covalent bonding between collagen molecules. This is true for both rabbit and equine collagen proveniences. Furthermore, soldering of pure collagen membranes without additional cellular components does not achieve the typical tensile strength reported in native, cell-rich tissues. This study is a first step in a better understanding of laser impact at the molecular level and might prove useful in engineering of combined

  15. Ultraviolet irradiation effects incorporation of nitrate and nitrite nitrogen into aquatic natural organic matter

    USGS Publications Warehouse

    Thorn, Kevin A.; Cox, Larry G.

    2012-01-01

    One of the concerns regarding the safety and efficacy of ultraviolet radiation for treatment of drinking water and wastewater is the fate of nitrate, particularly its photolysis to nitrite. In this study, 15N NMR was used to establish for the first time that UV irradiation effects the incorporation of nitrate and nitrite nitrogen into aquatic natural organic matter (NOM). Irradiation of 15N-labeled nitrate in aqueous solution with an unfiltered medium pressure mercury lamp resulted in the incorporation of nitrogen into Suwannee River NOM (SRNOM) via nitrosation and other reactions over a range of pH from approximately 3.2 to 8.0, both in the presence and absence of bicarbonate, confirming photonitrosation of the NOM. The major forms of the incorporated label include nitrosophenol, oxime/nitro, pyridine, nitrile, and amide nitrogens. Natural organic matter also catalyzed the reduction of nitrate to ammonia on irradiation. The nitrosophenol and oxime/nitro nitrogens were found to be susceptible to photodegradation on further irradiation when nitrate was removed from the system. At pH 7.5, unfiltered irradiation resulted in the incorporation of 15N-labeled nitrite into SRNOM in the form of amide, nitrile, and pyridine nitrogen. In the presence of bicarbonate at pH 7.4, Pyrex filtered (cutoff below 290–300 nm) irradiation also effected incorporation of nitrite into SRNOM as amide nitrogen. We speculate that nitrosation of NOM from the UV irradiation of nitrate also leads to production of nitrogen gas and nitrous oxide, a process that may be termed photo-chemodenitrification. Irradiation of SRNOM alone resulted in transformation or loss of naturally abundant heterocyclic nitrogens.

  16. Dual PI3K- and mTOR-inhibitor PI-103 can either enhance or reduce the radiosensitizing effect of the Hsp90 inhibitor NVP-AUY922 in tumor cells: The role of drug-irradiation schedule

    PubMed Central

    Djuzenova, Cholpon S.; Fiedler, Vanessa; Katzer, Astrid; Michel, Konstanze; Deckert, Stefanie; Zimmermann, Heiko; Sukhorukov, Vladimir L.; Flentje, Michael

    2016-01-01

    Inhibition of Hsp90 can increase the radiosensitivity of tumor cells. However, inhibition of Hsp90 alone induces the anti-apoptotic Hsp70 and thereby decreases radiosensitivity. Therefore, preventing Hsp70 induction can be a promising strategy for radiosensitization. PI-103, an inhibitor of PI3K and mTOR, has previously been shown to suppress the up-regulation of Hsp70. Here, we explore the impact of combining PI-103 with the Hsp90 inhibitor NVP-AUY922 in irradiated glioblastoma and colon carcinoma cells. We analyzed the cellular response to drug-irradiation treatments by colony-forming assay, expression of several marker proteins, cell cycle progression and induction/repair of DNA damage. Although PI-103, given 24 h prior to irradiation, slightly suppressed the NVP-AUY922-mediated up-regulation of Hsp70, it did not cause radiosensitization and even diminished the radiosensitizing effect of NVP-AUY922. This result can be explained by the activation of PI3K and ERK pathways along with G1-arrest at the time of irradiation. In sharp contrast, PI-103 not only exerted a radiosensitizing effect but also strongly enhanced the radiosensitization by NVP-AUY922 when both inhibitors were added 3 h before irradiation and kept in culture for 24 h. Possible reasons for the observed radiosensitization under this drug-irradiation schedule may be a down-regulation of PI3K and ERK pathways during or directly after irradiation, increased residual DNA damage and strong G2/M arrest 24 h thereafter. We conclude that duration of drug treatment before irradiation plays a key role in the concomitant targeting of PI3K/mTOR and Hsp90 in tumor cells. PMID:27224913

  17. Dual PI3K- and mTOR-inhibitor PI-103 can either enhance or reduce the radiosensitizing effect of the Hsp90 inhibitor NVP-AUY922 in tumor cells: The role of drug-irradiation schedule.

    PubMed

    Djuzenova, Cholpon S; Fiedler, Vanessa; Katzer, Astrid; Michel, Konstanze; Deckert, Stefanie; Zimmermann, Heiko; Sukhorukov, Vladimir L; Flentje, Michael

    2016-06-21

    Inhibition of Hsp90 can increase the radiosensitivity of tumor cells. However, inhibition of Hsp90 alone induces the anti-apoptotic Hsp70 and thereby decreases radiosensitivity. Therefore, preventing Hsp70 induction can be a promising strategy for radiosensitization. PI-103, an inhibitor of PI3K and mTOR, has previously been shown to suppress the up-regulation of Hsp70. Here, we explore the impact of combining PI-103 with the Hsp90 inhibitor NVP-AUY922 in irradiated glioblastoma and colon carcinoma cells. We analyzed the cellular response to drug-irradiation treatments by colony-forming assay, expression of several marker proteins, cell cycle progression and induction/repair of DNA damage. Although PI-103, given 24 h prior to irradiation, slightly suppressed the NVP-AUY922-mediated up-regulation of Hsp70, it did not cause radiosensitization and even diminished the radiosensitizing effect of NVP-AUY922. This result can be explained by the activation of PI3K and ERK pathways along with G1-arrest at the time of irradiation. In sharp contrast, PI-103 not only exerted a radiosensitizing effect but also strongly enhanced the radiosensitization by NVP-AUY922 when both inhibitors were added 3 h before irradiation and kept in culture for 24 h. Possible reasons for the observed radiosensitization under this drug-irradiation schedule may be a down-regulation of PI3K and ERK pathways during or directly after irradiation, increased residual DNA damage and strong G2/M arrest 24 h thereafter. We conclude that duration of drug treatment before irradiation plays a key role in the concomitant targeting of PI3K/mTOR and Hsp90 in tumor cells.

  18. Suppressive Effects of Tea Catechins on Breast Cancer.

    PubMed

    Xiang, Li-Ping; Wang, Ao; Ye, Jian-Hui; Zheng, Xin-Qiang; Polito, Curt Anthony; Lu, Jian-Liang; Li, Qing-Sheng; Liang, Yue-Rong

    2016-07-28

    Tea leaf (Camellia sinensis) is rich in catechins, which endow tea with various health benefits. There are more than ten catechin compounds in tea, among which epigallocatechingallate (EGCG) is the most abundant. Epidemiological studies on the association between tea consumption and the risk of breast cancer were summarized, and the inhibitory effects of tea catechins on breast cancer, with EGCG as a representative compound, were reviewed in the present paper. The controversial results regarding the role of tea in breast cancer and areas for further study were discussed.

  19. Suppressive Effects of Tea Catechins on Breast Cancer

    PubMed Central

    Xiang, Li-Ping; Wang, Ao; Ye, Jian-Hui; Zheng, Xin-Qiang; Polito, Curt Anthony; Lu, Jian-Liang; Li, Qing-Sheng; Liang, Yue-Rong

    2016-01-01

    Tea leaf (Camellia sinensis) is rich in catechins, which endow tea with various health benefits. There are more than ten catechin compounds in tea, among which epigallocatechingallate (EGCG) is the most abundant. Epidemiological studies on the association between tea consumption and the risk of breast cancer were summarized, and the inhibitory effects of tea catechins on breast cancer, with EGCG as a representative compound, were reviewed in the present paper. The controversial results regarding the role of tea in breast cancer and areas for further study were discussed. PMID:27483305

  20. Radiation-induced bystander effect in non-irradiated glioblastoma spheroid cells.

    PubMed

    Faqihi, Fahime; Neshastehriz, Ali; Soleymanifard, Shokouhozaman; Shabani, Robabeh; Eivazzadeh, Nazila

    2015-09-01

    Radiation-induced bystander effects (RIBEs) are detected in cells that are not irradiated but receive signals from treated cells. The present study explored these bystander effects in a U87MG multicellular tumour spheroid model. A medium transfer technique was employed to induce the bystander effect, and colony formation assay was used to evaluate the effect. Relative changes in expression of BAX, BCL2, JNK and ERK genes were analysed using RT-PCR to investigate the RIBE mechanism. A significant decrease in plating efficiency was observed for both bystander and irradiated cells. The survival fraction was calculated for bystander cells to be 69.48% and for irradiated cells to be 34.68%. There was no change in pro-apoptotic BAX relative expression, but anti-apoptotic BCL2 showed downregulation in both irradiated and bystander cells. Pro-apoptotic JNK in bystander samples and ERK in irradiated samples were upregulated. The clonogenic survival data suggests that there was a classic RIBE in U87MG spheroids exposed to 4 Gy of X-rays, using a medium transfer technique. Changes in the expression of pro- and anti-apoptotic genes indicate involvement of both intrinsic apoptotic and MAPK pathways in inducing these effects.

  1. Flattening a puckered cyclohexasilane ring by suppression of the pseudo-Jahn-Teller effect

    NASA Astrophysics Data System (ADS)

    Pokhodnya, Konstantin; Olson, Christopher; Dai, Xuliang; Schulz, Douglas L.; Boudjouk, Philip; Sergeeva, Alina P.; Boldyrev, Alexander I.

    2011-01-01

    We report the experimental and theoretical characterization of neutral Si6X12 (X = Cl, Br) molecules that contain D3d distorted six-member silicon rings due to a pseudo-Jahn-Teller (PJT) effect. Calculations show that filling the intervenient molecular orbitals with electron pairs of adduct suppresses the PJT effect in Si6X12, with the Si6 ring becoming planar (D6h) upon complex formation. The stabilizing role of electrostatic and covalent interactions between positively charged silicon atoms and chlorine atoms of the subject [Si6Cl14]2- dianionic complexes is discussed. The reaction of Si6Cl12 with a Lewis base (e.g., Cl-) to give planar [Si6Cl14]2- dianionic complexes presents an experimental proof that suppression of the PJT effect is an effective strategy in restoring high Si6 ring symmetry. Additionally, the proposed pathway for the PJT suppression has been proved by the synthesis and characterization of novel compounds containing planar Si6 ring, namely, [nBu4N]2[Si6Cl12I2], [nBu4N]2[Si6Br14], and [nBu4N]2[Si6Br12I2]. This work represents the first demonstration that PJT effect suppression is useful in the rational design of materials with novel properties.

  2. Effect of Thyrotropin Suppression Therapy on Bone in Thyroid Cancer Patients

    PubMed Central

    Hawley, Sarah T.; Haymart, Megan R.

    2016-01-01

    Background. The thyroid cancer incidence is rising. Despite current guidelines, controversy exists regarding the degree and duration of thyrotropin suppression therapy. Also, its potential skeletal effects remain a concern to physicians caring for thyroid cancer patients. We conducted a review of published data to evaluate existing studies focusing on the skeletal effects of thyrotropin suppression therapy in thyroid cancer patients. Materials and Methods. A systematic search of the PubMed, Ovid/Medline, and Cochrane Central Register of Controlled Trials databases was conducted. The retained studies were evaluated for methodological quality, and the study populations were categorized into premenopausal women, postmenopausal women, and men. Results. Twenty-five pertinent studies were included. Seven studies were longitudinal and 18 were cross-sectional. Of the 25 included studies, 13 were assigned an excellent methodological quality score. Three of 5 longitudinal studies and 3 of 13 cross-sectional studies reported decreased bone mineral density (BMD) in premenopausal women; 2 of 4 longitudinal studies and 5 of 13 cross-sectional studies reported decreased BMD in postmenopausal women. The remaining studies showed no effect on BMD. The only longitudinal study of men showed bone mass loss; however, cross-sectional studies of men did not demonstrate a similar effect. Conclusion. Studies to date have yielded conflicting results on the skeletal effects of thyrotropin suppression therapy and a knowledge gap remains, especially for older adults and men. Existing data should be cautiously interpreted because of the variable quality and heterogeneity. Identifying groups at risk of adverse effects from thyrotropin suppression therapy will be instrumental to providing focused and tailored thyroid cancer treatment. Implications for Practice: The standard treatment for thyroid cancer includes total thyroidectomy with or without radioactive iodine ablation, often followed by

  3. Infrared light irradiation diminishes effective charge transfer in slow sodium channel gating system

    NASA Astrophysics Data System (ADS)

    Plakhova, Vera B.; Bagraev, Nikolai T.; Klyachkin, Leonid E.; Malyarenko, Anna M.; Romanov, Vladimir V.; Krylov, Boris V.

    2001-02-01

    Effects of infrared light irradiation (IR) on cultured dorsal root ganglia cells were studied by the whole-cell patch-clamp technique. The IR field is demonstrated to diminish the effective charge transfer in the activation system from 6.2 +-0.6 to 4.5 +-0.4 in units of electron charge per e-fold change in membrane potential. The effects was blocked with ouabain. Our data is the first indication that sodium pump might be the molecular sensor of infrared irradiation in animal kingdom.

  4. Infrared light irradiation diminishes effective charge transfer in slow sodium channel gating system

    NASA Astrophysics Data System (ADS)

    Plakhova, Vera B.; Bagraev, Nikolai T.; Klyachkin, Leonid E.; Malyarenko, Anna M.; Romanov, Vladimir V.; Krylov, Boris V.

    2000-02-01

    Effects of infrared light irradiation (IR) on cultured dorsal root ganglia cells were studied by the whole-cell patch-clamp technique. The IR field is demonstrated to diminish the effective charge transfer in the activation system from 6.2 +-0.6 to 4.5 +-0.4 in units of electron charge per e-fold change in membrane potential. The effects was blocked with ouabain. Our data is the first indication that sodium pump might be the molecular sensor of infrared irradiation in animal kingdom.

  5. Mutations in human lymphocytes: effect of X- and UV-irradiation.

    PubMed

    Sanderson, B J; Dempsey, J L; Morley, A A

    1984-08-01

    The mutagenic effects of X- and UV-irradiation on human lymphocytes were studied using a highly efficient cloning technique. The hypoxanthine-guanine phosphoribosyl-transferase enzyme locus was used to study mutation induction, with mutant cells being selected by their ability to form a clone in the presence of the purine analogue 6-thioguanine. Mutation dose-response curves for X- and UV-irradiation were established by studying lymphocytes from 11 individuals on day 10 after irradiation. The mean mutation frequency of unirradiated lymphocytes was 2.9 X 10(-6) and there were dose-dependent increase to 9.5 X 10(-5) after 400 rad of X-irradiation, and to 5.6 X 10(-5) after 125 erg/mm2 of the UV. The expression time of X-ray-induced mutations was 3-7 days. Dose-responses were obtained for mutation frequency and survival following X-irradiation of proliferating and non-proliferating lymphocytes from 8 individuals. Compared with non-proliferating lymphocytes, the proliferating lymphocytes developed fewer mutations but had a greater mortality after irradiation

  6. Effect of gigaelectron volt Au-ion irradiation on the characteristics of ultrananocrystalline diamond films

    SciTech Connect

    Chen, Huang-Chin; Teng, Kuang-Yau; Tang, Chen-Yau; Lin, I-Nan; Sundaravel, Balakrishnan; Amirthapandian, Sankarakumar

    2010-12-15

    The effect of 2.245 GeV Au-ion irradiation/postannealing processes on the electron field emission (EFE) properties of ultrananocrystalline diamond (UNCD) films was investigated. Au-ion irradiation with a fluence of around 8.4x10{sup 13} ions/cm{sup 2} is required to induce a large improvement in the EFE properties of the UNCD films. Postannealing the Au-ion irradiated films at 1000 deg. C for 1 h slightly degraded the EFE properties of the films but the resulting EFE behavior was still markedly superior to that of pristine UNCD films. Transmission electron microscopy examinations revealed that the EFE properties of the UNCD films are primarily improved by Au-ion irradiation/postannealing processes because of the formation of nanographites along the trajectory of the irradiating ions, which results in an interconnected path for electron transport. In contrast, the induction of grain growth process due to Au-ion irradiation in UNCD films is presumed to insignificantly degrade the EFE properties for the films as the aggregates are scarcely distributed and do not block the electron conducting path.

  7. Biological effects of millimeter-wave irradiation. Final report, 15 April 1984-31 March 1986

    SciTech Connect

    Gandhi, O.P.; Hill, D.W.; Furia, L.; Iskander, M.F.; Ghodgaonkar, D.

    1987-04-01

    Experiments were conducted to verify the reported high degree of sensitivity of growth rates of yeast cultures to frequency of millimeter-wave irradiation in the band 41.650 to 41.798 GHz. A new irradiation chamber was designed and built to allow simultaneous irradiation and sham irradiation of recirculating suspension of Saccharomyces cerevisiae that were maintained with a temperature difference of less than 0.01 C. No difference larger than plus or minus 4% was ever detected in the growth rates at any of the highly stabilized (within plus or minus 50 Hz) irradiation frequencies for which the effects had been reported by earlier workers. Experiments were also performed to determine the Raman spectra of cultures of Bacillus megaterium to investigate if these are dependent on the stage of their life cycle as reported by Webb et al. The results were negative. A further study to investigate the ability of millimeter waves to induce conformational changes in lipid bilayers of dipalmitoylphosphatidycholine (DPPC) liposomes below and above the transition temperature of 41/sup 0/C also gave negative results. For these experiments the conformational characteristics of the liposomes were evaluated using Raman spectra with and without millimeter-wave irradiation at 41.650 GHz.

  8. Stimulatory effects of low-power laser irradiation on bone formation in vitro

    NASA Astrophysics Data System (ADS)

    Ozawa, Yasuhito; Shimizu, Noriyoshi; Mishima, Hiroyuki; Kariya, Genichiro; Yamaguchi, Masaru; Takiguchi, Hisashi; Iwasawa, Tadamasa; Abiko, Yoshimitsu

    1995-04-01

    The effect of low-power laser irradiation on bone formation in vitro were assessed. Osteoblast-like cells were isolated from rat calvariae of 21d rat fetuses. The cultured calvarial cells were irradiated with a low-power laser (830 nm, 60 mW) one time only or once daily for 21d at various energy doses (10.8-108 J/day). The number and the total area of mineralized bone modules that had developed in the culture dish on day 21 were evaluated. DNA content, alkaline phosphatase (ALP) activity and the amount of extra-cellular collagen were also measured. Calcium and phosphorus in bone nodules were examined with an X-ray microanalyzer. Laser irradiation significantly increased the number and the total area of bone nodules in a dose-dependent manner. Cell proliferation and ALP activity in the irradiation group were higher in the early and middle culture periods, while the collagen content was higher in the middle an late periods compared with the control. Calcium and phosphorus were both higher in the irradiation group. These findings indicate that laser irradiation may play a principal role in stimulating differentiation of osteoblasts during the early stage of the culture, resulting in increased bone formation through acceleration of bone nodule maturation.

  9. Effect of γ-irradiation on antioxidant and antiproliferative properties of oat β-glucan

    NASA Astrophysics Data System (ADS)

    Shah, Asima; Masoodi, F. A.; Gani, Adil; Ashwar, Bilal Ahmad

    2015-12-01

    The present study was undertaken to examine effect of γ-rays on the antioxidant and antiproliferative potential of β-glucan isolated from oats. Irradiation doses of 0, 2, 6 and 10 kGy were given to extracted β-glucan. The samples were characterized by Fourier transform infrared spectroscopy, Gel permeation chromatography and quantitative estimation by (1-3) (1-4) β-D-Glucan assay kit (Megazyme). The average molecular weight of non-irradiated β-glucan was 199 kDa that decreased to 70 kDa at 10 kGy. Both FT-IR spectrum and chemical analysis revealed that the extracted β-glucan was pure having minor impurities. Antioxidant activity was evaluated by DPPH, lipid peroxidation, reducing power, metal chelating ability and oxidative DNA damage assays. Results revealed increased antioxidant activity of β-glucan with the increase in irradiation dose. Irradiated β-glucan also exhibited dose dependent cancer cell growth inhibition with irradiation doses. The study revealed that the low molecular weight β-glucan with increased antioxidant and antiproliferative activities can be produced by irradiation treatment.

  10. Gamma-irradiation effect on a commercial composite anticorrosive pigment and acidity-to-alkalinity conversion

    NASA Astrophysics Data System (ADS)

    Song, Weiqiang; Niu, Kaihui; Wu, Longchao

    2016-05-01

    A commercial composite anticorrosive pigment based on aluminum dihydrogen tripolyphosphate was studied after exposure to gamma irradiation (Co60, 0, 20, 50, 100 and 150 kGy) using FTIR, XRD, TGA and acid-base titration technologies. Although the FTIR spectra showed that the effect of the irradiation on functional groups in the pigments was not obvious, the decrease in the crystal lattice parameters of the irradiated pigments was observed in the XRD spectra compared to the non-irradiated sample. But the extent of the lattice parameter decrease monotonically with the increase of absorbed dose from 20 to 150 kGy, which was attributed to the decomposition of water and the simultaneous occurrence of lattice damage when the pigments were exposed to gamma rays. Of particular significance was the displayed basicity of the aqueous solutions of the irradiated pigments compared to the acidity of the solution of the non-irradiated pigment, which was attributed to the decomposition of P-OH groups (combined water).

  11. Effect of linear polarized near-infrared light irradiation and light exercise on muscle performance.

    PubMed

    Demura, Tomohiro; Demura, Shinichi; Aoki, Hiroki; Uchida, Yuu; Yamaji, Shunsuke

    2011-01-01

    This study aimed to determine the effect of active warm-up by local muscle light exercise and passive warm-up by polarized light irradiation on skin and muscle temperatures and forearm muscle performance (muscle strength, power, endurance, and controlled force-exertion). Ten healthy males performed various grip tests before and after active (local muscle light exercise) and passive (linear polarized near-infrared light irradiation) warm-ups. An active warm-up involved intermittent gripping exercise (contraction: 1 second and relaxation: 1 second) for 10 minutes using a sponge. A passive warm-up consisted of polarized light irradiation to the forearm (superficial digital flexor) for 10 minutes (irradiation: 5 seconds and rest: 1 second). Skin and muscle temperatures were measured during both warm-ups. Skin and muscle temperatures increased significantly after 5 minutes of local muscle light exercise and after 10 minutes of polarized light irradiation. Temperatures were significantly higher after 6 minutes of local muscle light exercise than after 6 minutes of polarized light irradiation. There were no significant differences of muscle strength, power, and controlled force-exertion before and after either warm-up. Average force outputs in all conditions significantly decreased with exertion time, and at 30, 60, 90, and 120 seconds they were higher in both warm-up conditions than in the non-warm-up condition. In conclusion, both warm-ups may contribute to improve muscle endurance performance in the decreasing force phase.

  12. Effect of neutron irradiation on the mechanical properties of weld overlay cladding for reactor pressure vessel

    NASA Astrophysics Data System (ADS)

    Tobita, Tohru; Udagawa, Makoto; Chimi, Yasuhiro; Nishiyama, Yutaka; Onizawa, Kunio

    2014-09-01

    This study investigates the effects of high fluence neutron irradiation on the mechanical properties of two types of cladding materials fabricated using the submerged-arc welding and electroslag welding methods. The tensile tests, Charpy impact tests, and fracture toughness tests were conducted before and after the neutron irradiation with a fluence of 1 × 1024 n/m2 at 290 °C. With neutron irradiation, we could observe an increase in the yield strength and ultimate strength, and a decrease in the total elongation. All cladding materials exhibited ductile-to-brittle transition behavior during the Charpy impact tests. A reduction in the Charpy upper-shelf energy and an increase in the ductile-to-brittle transition temperature was observed with neutron irradiation. There was no obvious decrease in the elastic-plastic fracture toughness (JIc) of the cladding materials upon irradiation with high neutron fluence. The tearing modulus was found to decrease with neutron irradiation; the submerged-arc-welded cladding materials exhibited low JIc values at high temperatures.

  13. Effect of Nd: YAG laser irradiation on surface properties and bond strength of zirconia ceramics.

    PubMed

    Liu, Li; Liu, Suogang; Song, Xiaomeng; Zhu, Qingping; Zhang, Wei

    2015-02-01

    This study investigated the effect of neodymium-doped yttrium aluminum garnet (Nd: YAG) laser irradiation on surface properties and bond strength of zirconia ceramics. Specimens of zirconia ceramic pieces were divided into 11 groups according to surface treatments as follows: one control group (no treatment), one air abrasion group, and nine laser groups (Nd: YAG irradiation). The laser groups were divided by applying with different output power (1, 2, or 3 W) and irradiation time (30, 60, or 90 s). Following surface treatments, the morphological characteristics of ceramic pieces was observed, and the surface roughness was measured. All specimens were bonded to resin cement. After, stored in water for 24 h and additionally aged by thermocycling, the shear bond strength was measured. Dunnett's t test and one-way ANOVA were performed as the statistical analyses for the surface roughness and the shear bond strength, respectively, with α = .05. Rougher surface of the ceramics could be obtained by laser irradiation with higher output power (2 and 3 W). However, cracks and defects were also found on material surface. The shear bond strength of laser groups was not obviously increased, and it was significantly lower than that of air abrasion group. No significant differences of the shear bond strength were found among laser groups treated with different output power or irradiation time. Nd: YAG laser irradiation cannot improve the surface properties of zirconia ceramics and cannot increase the bond strength of the ceramics. Enhancing irradiation power and extending irradiation time cannot induce higher bond strength of the ceramics and may cause material defect.

  14. Effect of ultraviolet irradiation on mast cell-deficient W/Wv mice

    SciTech Connect

    Ikai, K.; Danno, K.; Horio, T.; Narumiya, S.

    1985-07-01

    The effect of UV irradiation on the skin was investigated in (WB-W/+) X (C57BL/6J-Wv/+)F1-W/Wv mice, which are genetically deficient in tissue mast cells. Their congenic littermates (+/+) and normal albino mice (ICR or BALB/c) were used as controls. Mice were irradiated with 500 mJ/cm2 of UVB and the increment of ear thickness was measured before and 6, 12, and 24 h after irradiation. Ear swelling in W/Wv mice at 12 and 24 h after irradiation was significantly smaller than that in +/+ and ICR mice. In contrast, the number of sunburn cells formed 24 h after UVB irradiation (200 or 500 mJ/cm2) was similar in W/Wv, +/+ and ICR mice. On the other hand, when mice were treated with 8-methoxy-psoralen (0.5%) plus UVA irradiation (4 J/cm2) (topical PUVA), ears of W/Wv and BALB/c mice, which were both white in color, were thickened similarly 72 h after treatment, but less swelling was observed in +/+ mice, which were black in skin color. The amount of prostaglandin D2 (PGD2) in ears, determined by radioimmunoassay specific for PGD2, was elevated 3-fold in +/+ and ICR mice at 3 h after irradiation with 500 mJ/cm2 of UVB in comparison with basal level without irradiation. However, such elevation was not observed in W/Wv mice. These results suggest that mast cells play an important role in UVB-induced inflammation, and PGs from mast cells are responsible at least in part for the development of this reaction. However, neither mast cells nor PGs contribute to the sunburn cell formation and ear swelling response by PUVA treatment.

  15. Effect of positron source irradiation on positronium annihilation in fine powdered alumina

    NASA Astrophysics Data System (ADS)

    Liu, Z. W.; Chen, Z. Q.

    2016-09-01

    Positron lifetime and Doppler broadening of positron annihilation radiation were measured as a function of time to study the irradiation effect by 22Na positron source in fine powdered alumina. The γ-Al2O3 samples were put in a vacuum chamber with a pressure of about 10-6 Torr and were cooled down to 10 K by a closed-cycle helium gas refrigerator. The irradiation of γ-Al2O3 samples by positron source was taken for a duration of about two days immediately after the sample was cooled down. After that, the sample was subjected to a warm up process from 10 K to 300 K with a step of 10 K. Positron lifetime and Doppler broadening spectra were measured simultaneously during these processes. Two long lifetime components corresponding to ortho-positronium annihilation were observed. A significant shortening of these long lifetime components and a large increase in S parameter is observed during irradiation. It is supposed that positron source irradiation creates a large number of paramagnetic centers on the surface of the γ-Al2O3 grains, which induce spin conversion quenching of positronium. The irradiation induced paramagnetic centers are unstable above 70 K and are nearly annealed out when the temperature rises to 190 K. After warming up of the sample to room temperature, the positron lifetime spectrum is identical to that before irradiation. It was also found that after irradiation, a medium long lifetime component of about 5 ns appears, of which the intensity increases with increasing irradiation time. This may be originated from the formation of the surface o-Ps state. This surface o-Ps state is also inhibited at elevated temperatures. Our results indicate that positronium is a very sensitive probe for the surface defects in porous materials.

  16. Effect of UV irradiation on evaporated ZnS films

    NASA Technical Reports Server (NTRS)

    Hass, G.; Heaney, J. B.; Hunter, W. R.; Angel, D. W.

    1980-01-01

    Evaporated ZnS films used as a component in reflectance enhancing or decreasing multilayer coatings for mirrors, transparent optical materials, and vacuum UV reflecting optics, are investigated with reference to the reflectance loss under UV irradiation and the formation of ZnO as a result of the decomposition of ZnS in the presence of oxygen. Reflectance measurements over a broad wavelength range reveal that the UV induced reflectance losses are generally restricted to wavelengths shorter than 4000 A and are most severe in the vacuum UV region. After 134 hr of UV exposure initially polycrystalline film of 150-200 A thick is completely converted to amorphous ZnO. The results demonstrate that caution should be exercised in employing ZnS as the outer layer in an optical coating system designed for use in the UV and vacuum UV regions.

  17. Fumonisin production on irradiated corn kernels: effect of inoculum size.

    PubMed

    Chulze, S N; Etcheverry, M G; Lecumberry, S E; Magnoli, C E; Dalcero, A M; Ramirez, M L; Pascale, M; Rodriguez, M I

    1999-07-01

    Production of fumonisins B1, B2, and B3 by Fusarium moniliforme was evaluated on irradiated corn kernels inoculated with different spore concentrations (10, 10(2), 10(3), 10(5), and 10(6)), a water activity of 0.97, and a temperature of 25 degrees C. There was a direct relationship between the level of toxin produced and inoculum size. The highest levels of total fumonisin produced after 35 days of incubation were 5,028 and 9,063 ng/g at 10(5) and 10(6) spores per ml, respectively. The pattern of fumonisin production (FB1 > FB2 > FB3) in cultures growing from different inocula was not affected during the 35 days of incubation. The ratio between FB2 and FB1 varied from 0.15 to 0.42, whereas the ratio between FB3 and FB1 varied from 0.34 to 0.87.

  18. Irradiation effects on thermal properties of LWR hydride fuel

    NASA Astrophysics Data System (ADS)

    Terrani, Kurt; Balooch, Mehdi; Carpenter, David; Kohse, Gordon; Keiser, Dennis; Meyer, Mitchell; Olander, Donald

    2017-04-01

    Three hydride mini-fuel rods were fabricated and irradiated at the MIT nuclear reactor with a maximum burnup of 0.31% FIMA or ∼5 MWd/kgU equivalent oxide fuel burnup. Fuel rods consisted of uranium-zirconium hydride (U (30 wt%)ZrH1.6) pellets clad inside a LWR Zircaloy-2 tubing. The gap between the fuel and the cladding was filled with lead-bismuth eutectic alloy to eliminate the gas gap and the large temperature drop across it. Each mini-fuel rod was instrumented with two thermocouples with tips that are axially located halfway through the fuel centerline and cladding surface. In-pile temperature measurements enabled calculation of thermal conductivity in this fuel as a function of temperature and burnup. In-pile thermal conductivity at the beginning of test agreed well with out-of-pile measurements on unirradiated fuel and decreased rapidly with burnup.

  19. Effects of X-ray irradiation on human spermatogenesis

    NASA Technical Reports Server (NTRS)

    Thorslund, T. W.; Paulsen, C. A.

    1972-01-01

    Direct cell kill and inhibition of mitosis have been suggested as mechanisms to explain the occurrence of absolute sterility following the irradiation of the testes. In order to obtain information on the existence and dose dependency of the mechanisms for man, a controlled study was initiated. Sixty-four men received a single midorgan dose to both of their testes ranging from 7.5 to 400r (f = .95). It was deduced from resulting pre-sterile period and sterile period data that both cell kill and mitosis halting mechanisms were operating. The maximum observed sterile period was 501 days with eventual recovery observed in each individual where the follow-up was complete. Thus man appears to be highly radiosensitive in regard to temporary sterility but quite radioresistant in regard to permanent sterility.

  20. Effects of X-ray irradiation on different stages of Sesamia nonagrioides Lefebvre (Lepidoptera: Noctuidae) and DNA damage

    NASA Astrophysics Data System (ADS)

    Avan Aksoy, Hatice; Yazıcı, Nizamettin; Erel, Yakup

    2017-01-01

    The corn stalk borer, Sesamia nonagrioides Lefebvre (Lepidoptera: Noctuidae) is an important corn pest in the Mediterranean countries. In this study, we investigated the influence of X-ray irradiation on different developmental stages, reproduction and DNA damage to the insect. Eggs (0-24 h old), larvae (5th instar), pupae (5 days after pupation) and adults (24 h after emergence) were irradiated with X-ray irradiation at target doses of 0 (control), 50, 100, 150 and 200 Gy. Eggs irradiated at all doses did not hatch. When 5th instar were irradiated pupation and adult emergence significantly decreased. Fecundity of adults from irradiated pupae was inhibited and no eggs were laid. Moreover, adult longevity decreased after irradiation compared to control. Larvae, pupae, and adults of S. nonagrioides were studied using the single-cell gel electrophoresis (DNA comet) directly after irradiation. X-ray irradiated larvae, pupae, and adults showed typical DNA fragmentation in a dose-dependent manner compared with cells from non-irradiated groups. The amount of DNA damage increased as doses increased and possibly could be used to estimate dose applied in commercial phytosanitary irradiation treatments. Furthermore, irradiation would be an effective phytosanitary treatment for shipped commodities at risk infestation with S. nonagrioides.

  1. Effects of antioxidant combinations on shelf stability of irradiated chicken sausage during storage

    NASA Astrophysics Data System (ADS)

    Hwang, Ko-Eun; Kim, Hyun-Wook; Song, Dong-Heon; Kim, Yong-Jae; Ham, Yun-Kyung; Lee, Ju-Woon; Choi, Yun-Sang; Kim, Cheon-Jei

    2015-01-01

    This study was conducted in order to investigate the combined effects of gamma irradiation (0, 2.5, and 5 kGy) and antioxidant combination, mugwort extract (ME) and ascorbic acid (Aa), on the pH, total color difference (ΔE), hue angle (H°), 2-thiobarbituricacid-reactive substances (TBARS) values, residual nitrite contents, and sensory evaluation in chicken sausage during storage. The pH values and sensory properties, except for color, of chicken sausage were not significantly affected by adding ME or treating irradiation during storage. However, ΔE, and H° values of samples containing ME (either alone or with Aa) were higher than that of control, whereas irradiation had no significant effect during storage. A combination of ME+Aa (0.2% ME+0.05% Aa) was effective at delaying lipid oxidation in irradiated chicken sausage. In addition, nitrite contents were reduced by gamma ray as a dose dependent manner and, particularly in ME+Aa was most effective in decreasing the residual nitrite. Our results suggested that gamma irradiation combined with an antioxidant mixture is a useful technology for reducing the residual nitrite and retarding the lipid oxidation in chicken sausage.

  2. [Effect of External Irradiation and Immobilization Stress on the Reproductive System of Male Rats].

    PubMed

    Vereschako, G G; Tshueshova, N V; Gorokh, G A; Kozlov, I G; Naumov, A D

    2016-01-01

    We studied the state of the reproductive system of male rats after irradiation at a dose of 2.0 Gy, immobilization stress (6 hours/day for 7 days) and their combined effects. On the 30th day after the combined treatment (37 days after irradiation) a decrease in the testicular weight by almost 50% compared with the control and lesions connected with the process of spermatogenesis are observed. In the remote period--on the 60th day (67th after irradiation) the effect of irradiation and irradiation in combination with immobilization stress leads to a sharp drop in the number of epididymal sperm (up to 18% of the control), and a reduction of their viability. The reaction ofthe reproductive system to the immobilization stress is expressed in a certain increase in the mass of the testes and epididymis, moderate imbalances in the composition of spermatogenic cells in the testis tissue, and in the long term--in the increased number of epididymal sperm and the decrease in their viability. Changes of testosterone in the blood serum, especially significant for the combined effect, reflect impairments of the regulation of the reproductive system of males under these conditions. With regard to individual indicators of the reproductive system of male rats in some cases, the- combined effects of radiation and stress had a synergistic, or, on the contrary, antagonistic character.

  3. Effect of Electron-Beam Irradiation on Organic Semiconductor and Its Application for Transistor-Based Dosimeters.

    PubMed

    Kim, Jae Joon; Ha, Jun Mok; Lee, Hyeok Moo; Raza, Hamid Saeed; Park, Ji Won; Cho, Sung Oh

    2016-08-03

    The effects of electron-beam irradiation on the organic semiconductor rubrene and its application as a dosimeter was investigated. Through the measurements of photoluminescence and the ultraviolet photoelectron spectroscopy, we found that electron-beam irradiation induces n-doping of rubrene. Additionally, we fabricated rubrene thin-film transistors with pristine and irradiated rubrene, and discovered that the decrease in transistor properties originated from the irradiation of rubrene and that the threshold voltages are shifted to the opposite directions as the irradiated layers. Finally, a highly sensitive and air-stable electron dosimeter was fabricated based on a rubrene transistor.

  4. Effect of γ-irradiation on commercial polypropylene based mono and multi-layered retortable food packaging materials

    NASA Astrophysics Data System (ADS)

    George, Johnsy; Kumar, R.; Sajeevkumar, V. A.; Sabapathy, S. N.; Vaijapurkar, S. G.; Kumar, D.; Kchawahha, A.; Bawa, A. S.

    2007-07-01

    Irradiation processing of food in the prepackaged form may affect chemical and physical properties of the plastic packaging materials. The effect of γ-irradiation doses (2.5-10.0 kGy) on polypropylene (PP)-based retortable food packaging materials, were investigated using Fourier transform infrared (FTIR) spectroscopic analysis, which revealed the changes happening to these materials after irradiation. The mechanical properties decreased with irradiation while oxygen transmission rate (OTR) was not affected significantly. Colour measurement indicated that Nylon 6 containing multilayer films became yellowish after irradiation. Thermal characterization revealed the changes in percentage crystallinity.

  5. Suppressive effects of 3-bromopyruvate on the proliferation and the motility of hepatocellular carcinoma cells.

    PubMed

    Tomizawa, Minoru; Shinozaki, Fuminobu; Motoyoshi, Yasufumi; Sugiyama, Takao; Yamamoto, Shigenori; Ishige, Naoki

    2016-01-01

    The compound 3-bromopyruvate (3BP) is an analogue of pyruvate, which is the final product of glycolysis that enters the citric acid cycle. The present study aimed to investigate the suppressive effects of 3BP on the proliferation and motility of hepatocellular carcinoma (HCC) cells. HLF and PLC/PRF/5 cells were cultured with 3BP and subjected to an MTS assay. Apoptosis was analyzed by hematoxylin and eosin staining. Cell motility was analyzed using a scratch assay. Real-time quantitative polymerase chain reaction (PCR) was performed to determine the expression levels of cyclin D1 and matrix metalloproteinase (MMP)9. Proliferation of both cell lines was significantly suppressed by 3BP at 100 µM (P<0.05). The expression level of cyclin D1 was decreased after 3BP treatment at 100 µM in both cell lines (P<0.05). Pyknotic nuclei were observed in the cells cultured with 3BP at 100 µM. These results revealed that 3BP suppressed cell proliferation, decreased the expression of cyclin D1, and induced apoptosis in HCC cells. 3BP significantly suppressed motility in both cell lines (P<0.05). The expression level of MMP9 was significantly decreased (P<0.05). 3BP suppressed the proliferation and motility of HCC cells by decreasing the expression of cyclin D1 and MMP9.

  6. Suppressive effects of 3-methylcholanthrene on the in vitro antitumor activity of naturally cytotoxic cells

    SciTech Connect

    Lill, P.H.; Gangemi, D.

    1986-01-01

    Transient suppression of splenic natural killer (NK), natural cytotoxic (NC) and peritoneal macrophage cytotoxicity was observed following a single injection of 3-methylcholanthrene (3-MC) into C3H/HeN mice. Natural killer cell activity was depressed by 30-60% 4-6 d after injection of 1.0 mg 3-MC. Levels of NK reactivity returned to normal 8 d post 3-MC injection, and no suppression of natural killing was seen when tested 6 wk after 3-MC treatment. 3-MC did not affect propionibacterium acnes augmentation of NK cell activity when tested both 6 d and 6 wk after carcinogen injection. The results indicate that the observed suppression of naturally cytotoxic cells may not be important in allowing 3-MC-induced tumors to grow, since suppression is not long-lasting. Therefore, any effect on tumor growth mediated by a suppression of naturally cytotoxic cells would have to be exerted at the earliest stages of tumor development.

  7. Modeling the effect of suppression on the periodicity of stimulus frequency otoacoustic emissions

    NASA Astrophysics Data System (ADS)

    Lineton, Ben; Lutman, Mark E.

    2003-08-01

    The distributed roughness theory of the origins of spectral periodicity in stimulus frequency otoacoustic emissions (SFOAEs) predicts that the spectral period will be altered by suppression of the traveling wave (TW) [Zweig and Shera, J. Acoust. Soc. Am. 98, 2018-2047 (1995)]. In order to investigate this effect in more detail, simulations of the variation of the spectral period under conditions of self-suppression and two-tone suppression are obtained from nonlinear cochlear models based on this theory. The results show that during self-suppression the spectral period is increased, while during high-side two-tone suppression, the period is reduced, indicating that the detailed pattern of disruption of the cochlear amplifier must be examined if the nonlinear behavior of SFOAEs is to be understood. The model results suggest that the SFOAE spectral period may be sensitive to changes in the state of the cochlear amplifier. A companion paper [Lineton and Lutman, J. Acoust. Soc. Am. 114, 871-882 (2003)] presents experimental data which are compared with the results of the above models with a view to testing the underlying theory of Zweig and Shera.

  8. Digital filter suppresses effects of nonstatistical noise bursts on multichannel scaler digital averaging systems

    NASA Technical Reports Server (NTRS)

    Goodman, L. S.; Salter, F. O.

    1968-01-01

    Digital filter suppresses the effects of nonstatistical noise bursts on data averaged over multichannel scaler. Interposed between the sampled channels and the digital averaging system, it uses binary logic circuitry to compare the number of counts per channel with the average number of counts per channel.

  9. Coordinating Comprehension and Production in Simultaneous Interpreters: Evidence from the Articulatory Suppression Effect

    ERIC Educational Resources Information Center

    Yudes, Carolina; Macizo, Pedro; Bajo, Teresa

    2012-01-01

    This study aimed to investigate the capacity of coordinating comprehension and production processes and the role of phonological working memory in simultaneous interpreting. To this end we evaluated the Articulatory Suppression (AS) effect in three groups of participants, monolingual controls, students of interpreting and professional…

  10. An Investigation of Tic Suppression and the Rebound Effect in Tourette's Disorder

    ERIC Educational Resources Information Center

    Meidinger, Amy L.; Miltenberger, Raymond G.; Himle, Michael; Omvig, Matthew; Trainor, Casey; Crosby, Ross

    2005-01-01

    Many patients, parents of children with Tourettes disorder, and professionals have suggested that following a period of suppression, tics will rebound to a rate that will exceed the average rate of occurrence. At present, there are no empirical data to support or refute such an effect. This experiment utilized an A-B-A design with replication to…

  11. Apical Dominance and Planting Density Effects on Weed Suppression by Sunn Hemp (Crotalaria juncea L.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A field study was conducted in 2008 and 2009 in Citra, Florida to evaluate the effects of seeding rate and removal of apical dominance of sunn hemp (Crotalaria juncea L.) on weed suppression and seed production of sunn hemp. Three seeding rates of sunn hemp were used; a representative seed producti...

  12. Suppression of tunneling rate fluctuations in tunnel field-effect transistors by enhancing tunneling probability

    NASA Astrophysics Data System (ADS)

    Mori, Takahiro; Migita, Shinji; Fukuda, Koichi; Asai, Hidehiro; Morita, Yukinori; Mizubayashi, Wataru; Liu, Yongxun; O’uchi, Shin-ichi; Fuketa, Hiroshi; Otsuka, Shintaro; Yasuda, Tetsuji; Masahara, Meishoku; Ota, Hiroyuki; Matsukawa, Takashi

    2017-04-01

    This paper discusses the impact of the tunneling probability on the variability of tunnel field-effect transistors (TFETs). Isoelectronic trap (IET) technology, which enhances the tunneling current in TFETs, is used to suppress the variability of the ON current and threshold voltage. The simulation results show that suppressing the tunneling rate fluctuations results in suppression of the variability. In addition, a formula describing the relationship between the tunneling rate fluctuations and the electric field strength is derived based on Kane’s band-to-band tunneling model. This formula indicates that the magnitude of the tunneling rate fluctuations is proportional to the magnitude of the fluctuations in the electric field strength and a higher tunneling probability results in a lower variability. The derived relationship is universally valid for any technologies that exploit enhancement of the tunneling probability, including IET technology, channel material engineering, heterojunctions, strain engineering, etc.

  13. The effect of electron beam irradiation on silver-sodium ion exchange in silicate glasses

    NASA Astrophysics Data System (ADS)

    Sidorov, Alexander I.; Prosnikov, Mikhail A.

    2016-04-01

    It is shown experimentally that electron irradiation of sodium-silicate glasses makes possible the control of the subsequent ion exchange Ag+ ↔ Na+ process in a salt melt. The reason of this effect is the negatively charged regions formation in a glass volume during electron irradiation. The electric field, produced by these regions in glass volume, results in positive Na+ ions field migration into them. The spatial redistribution of Na+ ions results in the decrease of the ion exchange efficiency, or the ion exchange can be even blocked. This led to the decrease of the luminescence intensity of neutral silver molecular clusters in the irradiated zone, and effect on the silver nanoparticles formation during the subsequent thermal treatment. The observed effects can be used for the control of ion exchange processes during integrated optics devices fabrication, and for the electron-beam recording of optical information.

  14. Effect of X-ray irradiation on fruit quality of clementine mandarin cv. ‘Clemenules’

    NASA Astrophysics Data System (ADS)

    Alonso, Miquel; Palou, Lluís; Ángel del Río, Miguel; Jacas, Josep-Anton

    2007-10-01

    The effects of a potential quarantine treatment consisting of exposure to X-ray irradiation against the Mediterranean fruit fly Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) on 'Clemenules' mandarin quality are presented and compared with those from the standard cold temperature quarantine treatment. X-ray irradiation doses of 0.195 and 0.395 kGy had no detrimental effects on fruit quality (rind color, firmness, juice yield, maturity index, internal volatiles, deterioration index and sensory evaluation). These results therefore indicate that X-ray irradiation is a harmless and highly effective quarantine technique for clementine mandarin and this technique could be as useful as the current cold treatment for 'Clemenules' mandarins.

  15. Effect of sound on gap-junction-based intercellular signaling: Calcium waves under acoustic irradiation

    NASA Astrophysics Data System (ADS)

    Deymier, P. A.; Swinteck, N.; Runge, K.; Deymier-Black, A.; Hoying, J. B.

    2015-11-01

    We present a previously unrecognized effect of sound waves on gap-junction-based intercellular signaling such as in biological tissues composed of endothelial cells. We suggest that sound irradiation may, through temporal and spatial modulation of cell-to-cell conductance, create intercellular calcium waves with unidirectional signal propagation associated with nonconventional topologies. Nonreciprocity in calcium wave propagation induced by sound wave irradiation is demonstrated in the case of a linear and a nonlinear reaction-diffusion model. This demonstration should be applicable to other types of gap-junction-based intercellular signals, and it is thought that it should be of help in interpreting a broad range of biological phenomena associated with the beneficial therapeutic effects of sound irradiation and possibly the harmful effects of sound waves on health.

  16. Protective effects of shikonin on brain injury induced by carbon ion beam irradiation in mice.

    PubMed

    Gan, Lu; Wang, Zhen Hua; Zhang, Hong; Zhou, Rong; Sun, Chao; Liu, Yang; Si, Jing; Liu, Yuan Yuan; Wang, Zhen Guo

    2015-02-01

    Radiation encephalopathy is the main complication of cranial radiotherapy. It can cause necrosis of brain tissue and cognitive dysfunction. Our previous work had proved that a natural antioxidant shikonin possessed protective effect on cerebral ischemic injury. Here we investigated the effects of shikonin on carbon ion beam induced radiation brain injury in mice. Pretreatment with shikonin significantly increased the SOD and CAT activities and the ratio of GSH/GSSG in mouse brain tissues compared with irradiated group (P<0.01), while obviously reduced the MDA and PCO contents and the ROS levels derived from of the brain mitochondria. The shikonin also noticeably improved the spatial memory deficits caused by carbon ion beam irradiation. All results demonstrated that shikonin could improve the irradiated brain injury which might resulted from its modulation effects on the oxidative stress induced by the 12C6+ ion beam.

  17. Manipulation of transport hysteresis on graphene field effect transistors with Ga ion irradiation

    SciTech Connect

    Wang, Quan; Liu, Shuai; Ren, Naifei

    2014-09-29

    We have studied the effect of Ga ion irradiation on the controllable hysteretic behavior of graphene field effect transistors fabricated on Si/SO{sub 2} substrates. The various densities of defects in graphene were monitored by Raman spectrum. It was found that the Dirac point shifted to the positive gate voltage constantly, while the hysteretic behavior was enhanced first and then weakened, with the dose of ion irradiation increasing. By contrasting the trap charges density induced by dopant and the total density of effective trap charges, it demonstrated that adsorbate doping was not the decisive factor that induced the hysteretic behavior. The tunneling between the defect sites induced by ion irradiation was also an important cause for the hysteresis.

  18. Effect of UV irradiation on the evaporation rate of alcohols droplets

    NASA Astrophysics Data System (ADS)

    Korobko, O. V.; Britan, A. V.; Verbinskaya, G. H.; Gavryushenko, D. A.

    2015-06-01

    The effect of ultraviolet irradiation with a wavelength of 390 nm on the evaporation of droplets of the homologous series of alcohols ( n-propanol, n-butanol, n-pentanol, n-heptanol, n-octanol, and n-decanol) at 10, 30, 50, 100, and 200 mm Hg in an atmosphere of dry nitrogen is studied. The values of the evaporation rate of alcohols are calculated with and without irradiation. Starting from n-pentanol, the rate of evaporation grows strongly for droplets of higher alcohols under the effect of low-power irradiation not associated with the heating of the evaporating droplets of alcohols. The obtained results are analyzed by comparing them to experimental data on neutron scattering by alcohols. It is shown that free convection must be considered in order to describe the evaporation process. Expressions of different authors for describing this effect are analyzed.

  19. Effect of sound on gap-junction-based intercellular signaling: Calcium waves under acoustic irradiation.

    PubMed

    Deymier, P A; Swinteck, N; Runge, K; Deymier-Black, A; Hoying, J B

    2015-01-01

    We present a previously unrecognized effect of sound waves on gap-junction-based intercellular signaling such as in biological tissues composed of endothelial cells. We suggest that sound irradiation may, through temporal and spatial modulation of cell-to-cell conductance, create intercellular calcium waves with unidirectional signal propagation associated with nonconventional topologies. Nonreciprocity in calcium wave propagation induced by sound wave irradiation is demonstrated in the case of a linear and a nonlinear reaction-diffusion model. This demonstration should be applicable to other types of gap-junction-based intercellular signals, and it is thought that it should be of help in interpreting a broad range of biological phenomena associated with the beneficial therapeutic effects of sound irradiation and possibly the harmful effects of sound waves on health.

  20. Effect of Grazing Angle Cross-Ion Irradiation on Ag Thin Films

    NASA Astrophysics Data System (ADS)

    Kumar, Manish; Jangid, Teena; Panchal, Vandana; Kumar, Praveen; Pathak, Abhishek

    2016-10-01

    Apart from the spherical shape, control over other shapes is a technical challenge in synthesis approaches of nanostructures. Here, we studied the effect of grazing angle cross-irradiation Ag thin films for the nanostructures evolution from a top-down approach. Ag thin films of different thicknesses were deposited on Si (100) and glass substrates by electron beam evaporation system and subsequently irradiated at grazing angle ions by 80 keV Ar+ in two steps (to induce effectively a cross-ion irradiation). Pristine films exhibited dense and uniform distribution of Ag nanoparticles with their characteristic surface plasmon resonance-induced absorption peak around 420 nm. When the film surfaces were treated with cross-grazing angle irradiation of Ar ions with varying effective fluences from 0.5 × 1017 ions/cm2 to 2.0 × 1017 ions/cm2, it was found that fluence values governed the competition of sputtering and sputter re-deposition of Ag. As a result, lower irradiation fluence favoured the formation of cone-like nanostructures, whereas high fluence values demonstrated dominant sputtering. Fluence-dependent modification of surface features was studied through the Fourier transform infrared spectroscopy and the Rutherford backscattering spectroscopy. Theoretical justifications for the underlying mechanisms are presented to justify the experimental results.

  1. Investigation of the bystander effect in MRC5 cells after acute and fractionated irradiation in vitro.

    PubMed

    Soleymanifard, Shokouhozaman; Toossi, Mohammad Taghi Bahreyni; Samani, Roghayeh Kamran; Mohebbi, Shokoufeh

    2014-04-01

    Radiation-induced bystander effect (RIBE) has been defined as radiation responses observed in nonirradiated cells. It has been the focus of investigators worldwide due to the deleterious effects it induces in nonirradiated cells. The present study was performed to investigate whether acute or fractionated irradiation will evoke a differential bystander response in MRC5 cells. A normal human cell line (MRC5), and a human lung tumor cell line (QU-DB) were exposed to 0, 1, 2, and 4Gy of single acute or fractionated irradiation of equal fractions with a gap of 6 h. The MRC5 cells were supplemented with the media of irradiated cells and their micronucleus frequency was determined. The micronucleus frequency after single and fractionated irradiation did not vary significantly in the MRC5 cells conditioned with autologous or QU-DB cell-irradiated media, except for 4Gy where the frequency of micronucleated cells was lower in those MRC5 cells cultured in the media of QU-DB-exposed with a single dose of 4Gy. Our study demonstrates that the radiation-induced bystander effect was almost similar after single acute and fractionated exposure in MRC5 cells.

  2. Effects of mouse genotype on bone wound healing and irradiation-induced delay of healing.

    PubMed

    Glowacki, Julie; Mizuno, Shuichi; Kung, Jason; Goff, Julie; Epperly, Michael; Dixon, Tracy; Wang, Hong; Greenberger, Joel S

    2014-01-01

    We tested the effects of mouse genotype (C57BL/6NHsd, NOD/SCID, SAMR1, and SAMP6) and ionizing irradiation on bone wound healing. Unicortical wounds were made in the proximal tibiae, and the time course of spontaneous healing and effects of irradiation were monitored radiographically and histologically. There was reproducible healing beginning with intramedullary osteogenesis, subsequent bone resorption by osteoclasts, gradual bridging of the cortical wound, and re-population of medullary hematopoietic cells. The most rapid wound closure was noted in SAMR1 mice, followed by SAMP6, C57BL/6NHsd, and NOD/SCID. Ionizing irradiation (20 Gy) to the leg significantly delayed bone wound healing in mice of all four genotypes. Mice with genetically-determined predisposition to early osteopenia (SAMP6) or with immune deficiency (NOD/SCID) had impairments in bone wound healing. These mouse models should be valuable for determining the effects of irradiation on bone healing and also for the design and testing of novel bone growth-enhancing drugs and mitigators of ionizing irradiation.

  3. Effects Of Continuous Argon Laser Irradiation On Canine And Autopsied Human Cardiac Tissue

    NASA Astrophysics Data System (ADS)

    Ben-Shachar, Giora; Sivakoff, Mark; Bernard, Steven L.; Dahms, Beverly B.; Riemenschneider, Thomas A.

    1984-10-01

    In eight human formalin preserved cardiac specimens, various cardiac and vascular obstructions were relieved by argon laser irradiation. Interatrial communication was also produced by a transar'rial approach in a live dog. In-vivo fresh canine cardiac tissues required power density of at feast 80, 90, and 110 watts/cm2 for vaporization of myocardial, vascular and valvular tissues respectively. The fiber tip to tissue distance (effective irradiation distance) for effective vaporization was less than I mm for vascular and valvular tissues and less than 4 mm for myocardium. Light microscopy showed four zones of histological damage common to all tissues - central crater surrounded by layers of charring, vacuolization and coagulation necorsis. Myocardium showed additionally a layer of normal appearing muscle cells (skip area) surrounded by a peripheral coagulation halo. Laser irradiation effects on valvular tissue showed the most lateral extension of coagulation necrosis. It is concluded that palliation and treatment of certain congenital heart defects by laser irradiation is anatomi-cally feasible and may be safe for in vivo application when low power output and short exposure time are used from a very short irradiation distance.

  4. Irradiation influence on the phenoloxidase pathway and an anti-oxidant defense mechanism in Spodoptera litura (Lepidoptera: Noctuidae) and its implication in radio-genetic 'F 1 sterility' and biorational pest suppression tactics.

    PubMed

    Sachdev, B; Khan, Z; Zarin, M; Malhotra, P; Seth, R K; Bhatnagar, R K

    2017-01-31

    The present study was conducted to appraise the ontogenic radio-sensitivity of a serious tropical pest, Spodoptera litura (Fabr.). The molecular responses pertaining to the phenoloxidase (PO) pathway and an anti-oxidant defense mechanism were evaluated in order to understand its implication in pest control at pre-harvest and post-harvest intervals. Irradiation exhibited an inverse relationship with age with respect to impact on developmental and transcriptional responses. Transcript abundance of PO cascade enzymes, prophenoloxidase (slppo-2), its activating enzyme (slppae-1) and free-radical scavenging enzymes, superoxide dismutase (slsod) and catalase (slcat) was evaluated upon gamma irradiation alone and the dual-stress of radiation plus microbial challenge. The slppo-2, slppae-1, slsod and slcat transcripts were significantly up-regulated in F 1 L6 larvae (6th-instar) resulting from 100 Gy sub-sterilized male adults and unirradiated female moths. The extent of upregulation was relatively higher in comparison with L6 survivors (6th-instar larvae) developed from irradiated neonates (L1) treated with 100 Gy. Upon Photorhabdus challenge, the transcripts were down-regulated in irradiated L1 suggesting increased larval susceptibility to bacterial infections. Radioresistance increased with the age of the insect, and molecular responses (transcript abundance) of insect defense mechanism were less influenced when older age (F 1 progeny) were irradiated. These findings will help to optimize the gamma dose to be employed in inherited sterility technique for (pre-harvest) pest suppression and (post-harvest) phytosanitation and quarantine, and suggest compatible integration of biorational tactics including nuclear technology.

  5. The effect of articulatory suppression on implicit and explicit false memory in the DRM paradigm.

    PubMed

    Van Damme, Ilse; Menten, Jan; d'Ydewalle, Gery

    2010-11-01

    Several studies have shown that reliable implicit false memory can be obtained in the DRM paradigm. There has been considerable debate, however, about whether or not conscious activation of critical lures during study is a necessary condition for this. Recent findings have revealed that articulatory suppression prevents subsequent false priming in an anagram task (Lovden & Johansson, 2003). The present experiment sought to replicate and extend these findings to an implicit word stem completion task, and to additionally investigate the effect of articulatory suppression on explicit false memory. Results showed an inhibitory effect of articulatory suppression on veridical memory, as well as on implicit false memory, whereas the level of explicit false memory was heightened. This suggests that articulatory suppression did not merely eliminate conscious lure activation, but had a more general capacity-delimiting effect. The drop in veridical memory can be attributed to diminished encoding of item-specific information. Superficial encoding also limited the spreading of semantic activation during study, which inhibited later false priming. In addition, the lack of item-specific and phenomenological details caused impaired source monitoring at test, resulting in heightened explicit false memory.

  6. Potential Suppressive Effects of Two C60 Fullerene Derivatives on Acquired Immunity

    NASA Astrophysics Data System (ADS)

    Hirai, Toshiro; Yoshioka, Yasuo; Udaka, Asako; Uemura, Eiichiro; Ohe, Tomoyuki; Aoshima, Hisae; Gao, Jian-Qing; Kokubo, Ken; Oshima, Takumi; Nagano, Kazuya; Higashisaka, Kazuma; Mashino, Tadahiko; Tsutsumi, Yasuo

    2016-10-01

    The therapeutic effects of fullerene derivatives on many models of inflammatory disease have been demonstrated. The anti-inflammatory mechanisms of these nanoparticles remain to be elucidated, though their beneficial roles in allergy and autoimmune diseases suggest their suppressive potential in acquired immunity. Here, we evaluated the effects of C60 pyrrolidine tris-acid (C60-P) and polyhydroxylated fullerene (C60(OH)36) on the acquired immune response in vitro and in vivo. In vitro, both C60 derivatives had dose-dependent suppressive effects on T cell receptor-mediated activation of T cells and antibody production by B cells under anti-CD40/IL-4 stimulation, similar to the actions of the antioxidant N-acetylcysteine. In addition, C60-P suppressed ovalbumin-specific antibody production and ovalbumin-specific T cell responses in vivo, although T cell-independent antibodies responses were not affected by C60-P. Together, our data suggest that fullerene derivatives can suppress acquired immune responses that require T cells.

  7. Antagonistic effect of polyamines on ABA-induced suppression of mitosis in Allium cepa L.

    PubMed

    Mahajan, Arpana; Sharma, Shashi

    2009-02-01

    Effect of abscisic acid (ABA) and polyamines (PAs) [putrescine (Put), spermidine (Spd) and spermine (Spm)] on mitosis in root tips of A. cepa was studied. Treatment with ABA (0.1 to 100 microM) for 24 hr suppressed the mitosis, measured as mitotic index (MI), in a concentration-dependent manner with approx. 50% suppression at 10 microM of ABA. Treatment with different PAs (1 to 100 microM) had differential mitosis suppression effect. Spm was most inhibitory followed by Spd and Put, respectively. The higher concentrations of PAs (1 mM Put; 0.1 and 1 mM Spd or Spm) caused cell distortion. Remarkably, a 24 hr pretreatment of root tips with PAs prior to ABA (100 microM) treatment resulted in a general concentration-dependent reversal of ABA-induced suppression of MI. Catalase (CAT) activity in the root tips, an indicator of redox metabolism, increased due to ABA treatment in a concentration-dependent manner, remained unaltered in response to Put and declined due to Spd and Spm (> or = 0.1 mM). However, all PAs, irrespective of their individual effects, generally antagonized the ABA-dependent increase in CAT activity. Data indicate the possibility of ABA-PA interaction in the regulation of mitosis.

  8. Partial-Breast Irradiation Versus Whole-Breast Irradiation for Early-Stage Breast Cancer: A Cost-Effectiveness Analysis

    SciTech Connect

    Sher, David J.; Wittenberg, Eve; Suh, W. Warren; Taghian, Alphonse G.; Punglia, Rinaa S.

    2009-06-01

    Purpose: Accelerated partial-breast irradiation (PBI) is a new treatment paradigm for patients with early-stage breast cancer. Although PBI may lead to greater local recurrence rates, it may be cost-effective because of better tolerability and lower cost. We aim to determine the incremental cost-effectiveness of PBI compared with whole-breast radiation therapy (WBRT) for estrogen receptor-positive postmenopausal women treated for early-stage breast cancer. Methods and Materials: We developed a Markov model to describe health states in the 15 years after radiotherapy for early-stage breast cancer. External beam (EB) and MammoSite (MS) PBI were considered and assumed to be equally effective, but carried different costs. Patients received tamoxifen, but not chemotherapy. Utilities, recurrence risks, and costs were adapted from the literature; the baseline utility for no disease after radiotherapy was set at 0.92. Probabilistic sensitivity analyses were performed to model uncertainty in the PBI hazard ratio, recurrence pattern, and patient utilities. Costs (in 2004 US dollars) and quality-adjusted life-years were discounted at 3%/y. Results: The incremental cost-effectiveness ratio for WBRT compared with EB-PBI was $630,000/quality-adjusted life-year; WBRT strongly dominated MS-PBI. One-way sensitivity analysis found that results were sensitive to PBI hazard ratio, recurrence pattern, baseline recurrence risk, and no evidence of disease PBI utility values. Probabilistic sensitivity showed that EB-PBI was the most cost-effective technique over a wide range of assumptions and societal willingness-to-pay values. Conclusions: EB-PBI was the most cost-effective strategy for postmenopausal women with early-stage breast cancer. Unless the quality of life after MS-PBI proves to be superior, it is unlikely to be cost-effective.

  9. Effect of ion flux on helium retention in helium-irradiated tungsten

    NASA Astrophysics Data System (ADS)

    Rivera, A.; Valles, G.; Caturla, M. J.; Martin-Bragado, I.

    2013-05-01

    Helium retention in irradiated tungsten leads to swelling, pore formation, sample exfoliation and embrittlement with deleterious consequences in many applications. In particular, the use of tungsten in future nuclear fusion plants is proposed due to its good refractory properties. However, serious concerns about tungsten survivability stems from the fact that it must withstand severe irradiation conditions. In magnetic fusion as well as in inertial fusion (particularly with direct drive targets), tungsten components will be exposed to low and high energy ion irradiation (helium), respectively. A common feature is that the most detrimental situations will take place in pulsed mode, i.e., high flux irradiation. There is increasing evidence of a correlation between a high helium flux and an enhancement of detrimental effects on tungsten. Nevertheless, the nature of these effects is not well understood due to the subtleties imposed by the exact temperature profile evolution, ion energy, pulse duration, existence of impurities and simultaneous irradiation with other species. Object Kinetic Monte Carlo is the technique of choice to simulate the evolution of radiation-induced damage inside solids in large temporal and space scales. We have used the recently developed code MMonCa (Modular Monte Carlo simulator), presented at COSIRES 2012 for the first time, to study He retention (and in general defect evolution) in tungsten samples irradiated with high intensity helium pulses. The code simulates the interactions among a large variety of defects and during the irradiation stage and the subsequent annealing steps. The results show that the pulsed mode leads to significantly higher He retention at temperatures higher than 700 K. In this paper we discuss the process of He retention in terms of trap evolution. In addition, we discuss the implications of these findings for inertial fusion.

  10. Biological effects of gamma-irradiation on laboratory and field isolates of Eimeria tenella (Protozoa; Coccidia).

    PubMed

    Gilbert, J M; Fuller, A L; Scott, T C; McDougald, L R

    1998-06-01

    Sporulated oocysts of a field strain (FS-111) and a laboratory strain (WIS) of Eimeria tenella were exposed to 0, 50, 100, 150, or 200 Gy of gamma-radiation from a 60Co source. Irradiated oocysts of WIS and FS-111 were not significantly more fragile after irradiation as shown by the release of sporocysts after 5-105 s of vortex agitation with glass beads. Excystation was normal in both strains after treatment of the sporocysts with trypsin and sodium taurodeoxycholate, even in groups exposed to 200 Gy of radiation. Sporozoite release from irradiated sporocysts was more rapid than that from unirradiated sporocysts, primarily because of a shorter lag phase during the first 30 min. Irradiated sporozoites were slower to parasitize cultured chick kidney cells than were control sporozoites (4 h postinoculation), but after 24 h there was no significant difference (P < 0.05) between irradiated and control groups except for the WIS treated with 200 Gy. After 48 h, developing schizonts were reduced by 77-94% on exposure to 50-200 Gy. Strain FS-111 did not develop as well as WIS in vitro, but the effect of irradiation was similar. When irradiated oocysts of WIS or FS-111 were inoculated into chickens the prepatent period was unaffected, but fewer oocysts were produced, lesion scores were lower, and the weight gain was less strongly affected in proportion to the doses of radiation. These results suggest that the effects of radiation damage were largely confined to the mechanism of nuclear and cellular reproduction rather than other physiological processes.

  11. Effects of Ion Irradiation on Seedlings Growth Monitored by Ultraweak Delayed Luminescence

    PubMed Central

    Abe, Tomoko; Cirrone, Giuseppe A. P.; Cuttone, Giacomo; Gulino, Marisa; Musumeci, Francesco; Romano, Francesco; Ryuto, Hiromichi; Scordino, Agata

    2016-01-01

    The optical technique based on the measurement of delayed luminescence emitted from the biological samples has demonstrated its ability to provide valid and predictive information on the functional status of various biological systems. We want to extend this technique to study the effect of ionizing radiation on biological systems. In particular we are interested in the action of ion beams, used for therapeutic purposes or to increase the biological diversity. In general, the assessment of the damage that radiation produces both in the target objects and in the surrounding tissues, requires considerable time because is based on biochemical analysis or on the examination of the evolution of the irradiated systems. The delayed luminescence technique could help to simplify this investigation. We have so started our studies performing irradiations of some relatively simple vegetable models. In this paper we report results obtained from mung bean (Vigna radiata) seeds submitted to a 12C ion beam at the energy of 62 MeV/nucleon. The dry seeds were irradiated at doses from 50 to 7000 Gy. The photoinduced delayed luminescence of each seed before and after ion irradiation was measured. The growth of seedlings after irradiation was compared with that of untreated seeds. A growth reduction on increasing the dose was registered. The results show strong correlations between the ion irradiation dose, seeds growth and delayed luminescence intensity. In particular, the delayed luminescence intensity is correlated by a logistic function to the seedlings elongation and, after performing a suitable measurement campaign based on blind tests, it could become a tool able to predict the growth of seeds after ion irradiation. Moreover these results demonstrate that measurements of delayed luminescence could be used as a fast and non-invasive technique to check the effects of ion beams on relatively simple biological systems. PMID:27936220

  12. Immunomodulatory effect of captopril and local irradiation on myeloid-derived suppressor cells

    PubMed Central

    Cho, Won Kyung; Shin, Sung-Won; Kim, Shin-Yeong; Hong, Chang-Won; Choi, Changhoon; Park, Won; Noh, Jae Myoung

    2016-01-01

    Purpose This study is to investigate the effect of captopril when combined with irradiation. Materials and Methods 4T1 (mouse mammary carcinoma) cells were injected in the right hind leg of Balb/c mice. Mice were randomized to four groups; control (group 1), captopril-treated (group 2), irradiated (group 3), irradiated and captopril-treated concurrently (group 4). Captopril was administered by intraperitoneal injection (10 mg/kg) daily and irradiation was delivered on the tumor-bearing leg for 15 Gy in 3 fractions. Surface markers of splenic neutrophils (G-MDSCs) and intratumoral neutrophils (tumor-associated neutrophils [TANs]) were assessed using flow cytometry and expression of vascular endothelial growth factor (VEGF) and hypoxia-inducible factor 1 alpha (HIF-1α) of tumor was evaluated by immunohistochemical (IHC) staining. Results The mean tumor volumes (±standard error) at the 15th day after randomization were 1,382.0 (±201.2) mm3 (group 1), 559.9 (±67.8) mm3 (group 3), and 370.5 (± 48.1) mm3 (group 4), respectively. For G-MDSCs, irradiation reversed decreased expression of CD101 from tumor-bearing mice, and additional increase of CD101 expression was induced by captopril administration. Similar tendency was observed in TANs. The expression of tumor-necrosis factor-associated molecules, CD120 and CD137, are increased by irradiation in both G-MDSCs and TANs. Further increment was observed by captopril except CD120 in TANs. For IHC staining, VEGF and HIF-1α positivity in tumor cells were decreased when treated with captopril. Conclusion Captopril is suggested to have additional effect when combined to irradiation in a murine tumor model by modulation of MDSCs and angiogenesis. PMID:27609109

  13. Helium effects on the mechanical properties of neutron-irradiated Cr-Mo ferritic steels

    SciTech Connect

    Klueh, R.L.

    1990-01-01

    In the first wall of a fusion rector, large amounts of transmutation helium will be produced simultaneously with the displacement damage caused by high-energy neutrons from the fusion reaction. One method used to simulate irradiation effects for ferritic steels is to add nickel to the steels and irradiate them in a mixed-spectrum reactor. Fast neutrons in the spectrum produce displacement damage, while transmutation helium is produced by a two-step reaction of {sup 58}Ni with thermal neutrons. This technique has been used to investigate the effect of helium on tensile properties and toughness. Results from these studies are summarized.

  14. Effects of gamma irradiation on chemical composition and ruminal protein degradation of canola meal

    NASA Astrophysics Data System (ADS)

    Shawrang, P.; Nikkhah, A.; Zare-Shahneh, A.; Sadeghi, A. A.; Raisali, G.; Moradi-Shahrebabak, M.

    2008-07-01

    Gamma irradiation of canola meal (at doses of 25, 50 and 75 kGy) could alter its ruminal protein degradation characteristics by cross-linking of the polypeptide chains. This processing resulted in decrease (linear effect, P<0.001) of ruminal protein degradation and increase (linear effect, P<0.001) of intestinal protein digestibility. The results showed that gamma irradiation at doses higher than 25 kGy can be used as a cross-linking agent to improve protein properties of supplements in ruminant nutrition.

  15. Effects of Prenatal Irradiation on Fetal, Neonate, and Young Adult Murine Hemopoiesis

    DTIC Science & Technology

    1983-01-01

    mEffects of prenatal irradiation ,9t on fetal , neonate, and young < adult murine hemopoiesis S. R. Weinberg ,C:),x’--, ::- CTE L,: -’ A U U 6 19 8 4...4L/ 4. TITLE (and Subtitle) 5. TYPE OF REPORT & PERIOD COVERED EFFECTS OF PRENATAL IRRADIATION ON FETAL , NEONATE, AND YOUNG ADULT MURINE HEMOPOIESIS 7...studied at four seleeted age pr)Ciods: (a) day 14.5 of gestation, (b) tieonate, (c) juvenile, and (d) 13 week-old adult. Fetal liver eellularity

  16. The effects of lipid A on gamma-irradiated human peripheral blood lymphocytes in vitro

    NASA Astrophysics Data System (ADS)

    Dubničková, M.; Kuzmina, E. A.; Chausov, V. N.; Ravnachka, I.; Boreyko, A. V.; Krasavin, E. A.

    2016-03-01

    The modulatory effects of lipid A (diphosphoryl lipid A (DLA) and monophosphoryl lipid A (MLA)) on apoptosis induction and DNA structure damage (single and double-strand breaks (SSBs and DSBs, respectively)) in peripheral human blood lymphocytes are studied for 60Co gamma-irradiation. It is shown that in the presence of these agents the amount of apoptotic cells increases compared with the irradiated control samples. The effect is most strongly pronounced for DLA. In its presence, a significant increase is observed in the number of radiation-induced DNA SSBs and DSBs. Possible mechanisms are discussed of the modifying influence of the used agents on radiation-induced cell reactions

  17. Effect of ionizing irradiation on the physiological activity of cyclic adenosine monophosphate on smooth muscle preparations.

    PubMed

    Schachinger, L; Michailov, M; Owusa Daaku, S; Prechter, I; Klöter, H; Schippel, C

    1982-01-01

    The effect of ionizing irradiation on the physiological activity of cyclic adenosine monophosphate (cAMP) in smooth muscle preparations from frog lung was studied. cAMP, given as dibutyryl salt (dib-cAMP) inhibited the radiation induced contractions of the muscle in a manner similar to the action of theophylline. In vitro irradiation of dib-cAMP resulted in an alteration of the chemical structure of this substance, i.e., formation of monobutyryl-cAMP and further derivatives as well as a decomposition of the purine structure. There was also a loss of the relaxing activity of irradiated cAMP on the muscle tone of frog lung preparations. The physiologically measured inactivation of dib-cAMP was far more pronounced than the chemical alteration. An inhibitory effect of the reaction products is postulated.

  18. Tissue-protective effects of fullerenol C60(OH)24 and amifostine in irradiated rats.

    PubMed

    Trajković, Sanja; Dobrić, Silva; Jaćević, Vesna; Dragojević-Simić, Viktorija; Milovanović, Zoran; Dordević, Aleksandar

    2007-07-01

    Polyhydroxylated fullerenes, named fullerenols (C(60)(OH)(n); n=12-26) are excellent antioxidants. Harmful effects of ionizing radiation on living organism are mainly mediated by free radical species and fullerenols attract an attention as a potential radioprotectors. Our preliminary investigations on mice and rats subjected to radiation injury show that fullerenol C(60)(OH)(24) provides high survival rate of irradiated small rodents. Radioprotective effect was comparable to that of the standard radioprotector amifostine. The aim of this study was to compare the efficacy of fullerenol C(60)(OH)(24) (10 and 100mg/kg i.p.) and amifostine (300 mg/kg i.p.) in protection of rats against harmful effects of ionizing radiation. The animals were whole-body irradiated by X-rays (8 MV). Both compounds were given 30 min before irradiation. In order to evaluate the general radioprotective efficacy of fullerenol and amifostine rats were irradiated with an absolutely lethal dose of X-rays (8 Gy) and their survival and body mass gain were monitored during the period of 30 days after irradiation. The aim of the second part of the study is to investigate the tissue-protective effects of tested compounds (100 mg/kg i.p. of fullerenol and 300 mg/kg i.p. of amifostine, 30 min before irradiation). It was carried out on rats irradiated with a sublethal dose of X-rays (7 Gy). Influence of ionizing radiation on hematopoesis as well as the radioprotective efficiency of the compounds given were evaluated by determining blood cell count during 28 days after irradiation. For this purpose the blood was taken from tail vein before irradiation and on the 3rd, 7th, 14th, 21st and 28th day after irradiation. In order to estimate the radioprotective effects of fullerenol and amifostine on other rat tissue, the animals were sacrificed on the 7th and 28th day after irradiation and their main organs (lung, heart, liver, kidney, small intestine and spleen) were taken for histopathological analysis. In

  19. Laser irradiation of carbon nanotube films: Effects and heat dissipation probed by Raman spectroscopy

    SciTech Connect

    Mialichi, J. R.; Brasil, M. J. S. P.; Iikawa, F.; Verissimo, C.; Moshkalev, S. A.

    2013-07-14

    We investigate the thermal properties of thin films formed by single- and multi-walled carbon nanotubes submitted to laser irradiation using Raman scattering as a probe of both the tube morphology and the local temperature. The nanotubes were submitted to heating/cooling cycles attaining high laser intensities ({approx}1.4 MW/cm{sup 2}) under vacuum and in the presence of an atmosphere, with and without oxygen. We investigate the heat diffusion of the irradiated nanotubes to their surroundings and the effect of laser annealing on their properties. The presence of oxygen during laser irradiation gives rise to an irreversible increase of the Raman efficiency of the carbon nanotubes and to a remarkable increase of the thermal conductivity of multi-walled films. The second effect can be applied to design thermal conductive channels in devices based on carbon nanotube films using laser beams.

  20. The effects of gamma irradiation on neutron displacement sensitivity of lateral PNP bipolar transistors

    NASA Astrophysics Data System (ADS)

    Wang, Chenhui; Chen, Wei; Liu, Yan; Jin, Xiaoming; Yang, Shanchao; Qi, Chao

    2016-09-01

    The effects of gamma irradiation on neutron displacement sensitivity of four types of lateral PNP bipolar transistors (LPNPs) with different neutral base widths, emitter widths and the doping concentrations of the epitaxial base region are studied. The physical mechanisms of the effects are explored by defect analysis using deep level transient spectroscopy (DLTS) techniques and numerical simulations of recombination process in the base region of the lateral PNP bipolar transistors, and are verified by the experiments on gate-controlled lateral PNP bipolar transistors (GCLPNPs) manufactured in the identical commercial bipolar process with different gate bias voltage. The results indicate that gamma irradiation increases neutron displacement damage sensitivity of lateral PNP bipolar transistors and the mechanism of this phenomenon is that positive charge induced by gamma irradiation enhances the recombination process in the defects induced by neutrons in the base region, leading to larger recombination component of base current and greater gain degradation.