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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. Suppressed tuberculin reaction in guinea pigs following laser irradiation

    SciTech Connect

    Inoue, K.; Nishioka, J.; Hukuda, S.

    1989-01-01

    Tuberculin reactions were tested at the bilateral sites of the backs of sensitized guinea pigs. Laser irradiation at an energy fluence of 3.6 J at one site of reaction suppressed the reaction not only at the irradiated site but also at the contralateral nonirradiated site. These phenomena were observed when mononuclear cells were dominant in the perivascular cellular infiltration. The results indicate that local irradiation with a low-power laser has systemic inhibitory effects on delayed hypersensitivity reactions.

  3. Treatment Combining X-Irradiation and a Ribonucleoside Anticancer Drug, TAS106, Effectively Suppresses the Growth of Tumor Cells Transplanted in Mice

    SciTech Connect

    Yasui, Hironobu; Inanami, Osamu; Asanuma, Taketoshi; Iizuka, Daisuke; Nakajima, Takayuki; Kon, Yasuhiro; Matsuda, Akira; Kuwabara, Mikinori . E-mail: kuwabara@vetmed.hokudai.ac.jp

    2007-05-01

    Purpose: To examine the in vivo antitumor efficacy of X-irradiation combined with administration of a ribonucleoside anticancer drug, 1-(3-C-ethynyl-{beta}-D-ribo-pentofuranosyl)cytosine (TAS106, ECyd), to tumor cell-transplanted mice. Methods and Materials: Colon26 murine rectum adenocarcinoma cells and MKN45 human gastric adenocarcinoma cells were inoculated into the footpad in BALB/c mice and severe combined immunodeficient mice, respectively. They were treated with a relatively low dose of X-irradiation (2 Gy) and low amounts of TAS106 (0.1 mg/kg and 0.5 mg/kg). The tumor growth was monitored by measuring the tumor volume from Day 5 to Day 16 for Colon26 and from Day 7 to Day 20 for MKN45. Histologic analyses for proliferative and apoptotic cells in the tumors were performed using Ki-67 immunohistochemical and terminal deoxynucleotidyl transferase-mediated nick end labeling staining. The expression of survivin, a key molecule related to tumor survival, was assessed by quantitative polymerase chain reaction and immunohistochemical analysis. Results: When X-irradiation and TAS106 treatment were combined, significant inhibition of tumor growth was observed in both types of tumors compared with mice treated with X-irradiation or TAS106 alone. Marked inhibition of tumor growth was observed in half of the mice that received the combined treatment three times at 2-day intervals. Parallel to these phenomena, the suppression of survivin expression and appearance of Ki-67-negative and apoptotic cells were observed. Conclusions: X-irradiation and TAS106 effectively suppress tumor growth in mice. The inhibition of survivin expression by TAS106 is thought to mainly contribute to the suppression of the tumor growth.

  4. Suppression of IgE antibody production in SJL mice. V. Effect of irradiation and adult thymectomy on the suppression of IgE antibody production in SJL mice

    SciTech Connect

    Watanabe, N.; Ovary, Z.

    1983-07-15

    Anti-DNP IgE antibody production was low and transient in SJL mice which were immunized with 1 microgram DNP-Nb and 1 mg A1(OH)/sub 3/. The immunized SJL mice were irradiated (60-540 R) 1 day after challenge. A dose higher than 180 R induced enhancement of anti-DNP IgE antibody production as compared to nonirradiated control mice, suggesting the existence of irradiation-sensitive suppressor cells. Anti-DNP IgE antibody production was suppressed when immunized and irradiated SJL mice were injected with spleen cells from adult-thymectomized SJL mice. The donors of the spleen cells were thymectomized 2 or 4 months previously, and this suggests that the suppressor cells from unprimed mice are long-living T cells.

  5. 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.

  6. Suppression of shear banding in amorphous ZrCuAl nanopillars by irradiation

    NASA Astrophysics Data System (ADS)

    Xiao, Qiran; Huang, Liping; Shi, Yunfeng

    2013-02-01

    Using molecular dynamics simulations, model Zr50Cu40Al10 metallic glass (MG) nanopillars were subjected to simulated irradiation processes followed by uniaxial compression tests. As the intensity or dosage of irradiation increases, the plastic deformation mode of the MG nanopillars transits from localized shear banding to homogeneous shear flow. The suppression of shear banding in MG nanopillars is due to irradiation-induced structural disordering. Furthermore, a correlation is found between the average potential energy of MG nanopillars and their deformation modes, common to both irradiation processing and thermal processing. Our results imply that the homogeneous shear flow observed in experimental MG nanopillars carved by focused ion beam may be due to irradiation damage instead of size effect.

  7. Blue light irradiation suppresses dendritic cells activation in vitro.

    PubMed

    Fischer, Michael R; Abel, Manuela; Lopez Kostka, Susanna; Rudolph, Berenice; Becker, Detlef; von Stebut, Esther

    2013-08-01

    Blue light is a UV-free irradiation suitable for treating chronic skin inflammation, for example, atopic dermatitis, psoriasis, and hand- and foot eczema. However, a better understanding of the mode of action is still missing. For this reason, we investigated whether dendritic cells (DC) are directly affected by blue light irradiation in vitro. Here, we report that irradiation neither induced apoptosis nor maturation of monocyte-derived and myeloid DC. However, subsequent DC maturation upon LPS/IFNγ stimulation was impaired in a dose-dependent manner as assessed by maturation markers and cytokine release. Moreover, the potential of this DC to induce cytokine secretion from allogeneic CD4 T cells was reduced. In conclusion, unlike UV irradiation, blue light irradiation at high and low doses only resulted in impaired DC maturation upon activation and a reduced subsequent stimulatory capacity in allogeneic MLRs with strongest effects at higher doses. PMID:23879817

  8. Photosensitizer effect of 9-hydroxypheophorbide α on diode laser-irradiated laryngeal cancer cells: Oxidative stress-directed cell death and migration suppression

    PubMed Central

    He, Peijie; Bo, Shen; Chung, Phil-Sang; Ahn, Jin-Chul; Zhou, Liang

    2016-01-01

    The present study aimed to investigate the effect, and elucidate the potential mechanisms, of 9-hydroxypheophorbide α-based photodynamic therapy (9-HPbD-PDT) on apoptosis and necrosis induction, and migration suppression of laryngeal cancer AMC-HN-3 (HN-3) cells. Phototoxicity initiated by 9-HPbD-PDT on HN-3 cells was observed in a photosensitizer dose-dependent pattern. There was an initial increase of apoptotic cells coupled with gradual enhancement of reactive oxygen series (ROS) generation at lower doses of 9-HPbD. By contrast, at a higher dose of 9-HPbD, there was a clear increase of necrotic cells with a gradual decrease of ROS generation. Following PDT, an elevated percentage of apoptotic cells with shrinkage or condensing nuclei was observed using Hoechst 33342/propidium iodide double staining, and an upregulated expression of poly ADP-ribose polymerase was detected through western blotting. A disruption of the mitochondrial membrane potential was detected 2 h following PDT. Significant suppression of cell migration and downregulation of epidermal growth factor receptor (EGFR) expression were recorded following PDT. These results indicate that the distribution of photosensitizer leads to differences in the generation of ROS, which subsequently determines the type of cell death. Overall, mitochondrial activation under oxidative stress is important in the 9-HPbD-PDT-induced apoptosis of HN-3 cells. Migration suppression of HN-3 cells following PDT may be associated with the inhibited expression of EGFR, due to oxidative stress. PMID:27588136

  9. Systemic suppression of delayed-type hypersensitivity by supernatants from UV-irradiated keratinocytes

    SciTech Connect

    Rivas, J.M.; Ullrich, S.E. )

    1992-12-15

    Exposing murine keratinocyte cultures to UV radiation causes the release of a suppressive cytokine that mimics the immunosuppressive effects of total-body UV exposure. Injecting supernatants from UV-irradiated keratinocyte cultures into mice inhibits their ability to generate a delayed-type hypersensitivity reaction against allogeneic histocompatibility Ag, and spleen cells from mice injected with supernatant do not respond to alloantigen in the in vitro MLR. A unique feature of the immunosuppression induced by either total-body UV-exposure or injecting the suppressive cytokine from UV-irradiated keratinocytes is the selectivity of suppression. Although cellular immune reactions such as delayed-type hypersensitivity are suppressed antibody production is unaffected. Because the selective nature to the UV-induced immunosuppression is similar to the biologic activity of IL-10, the authors examined the hypothesis that UV exposure of keratinocytes causes the release of IL-10. Keratinocyte monolayers were exposed to UV radiation and at specific times after exposure mRNA was isolated or the culture supernatant from the cells was collected. These data indicate that activated keratinocytes are capable of secreting IL-10 and suggest that the release of IL-10 by UV-irradiated keratinocytes plays an essential role in the induction of systemic immunosuppression after total-body UV exposure. 44 refs., 3 figs., 2 tabs.

  10. Basophil-derived amphiregulin is essential for UVB irradiation-induced immune suppression.

    PubMed

    Meulenbroeks, Chantal; van Weelden, Huib; Schwartz, Christian; Voehringer, David; Redegeld, Frank A M; Rutten, Victor P M G; Willemse, Ton; Sijts, Alice J A M; Zaiss, Dietmar M W

    2015-01-01

    UVB irradiation (290-320 nm) is used to treat skin diseases like psoriasis and atopic dermatitis, and is known to suppress contact hypersensitivity (CHS) reactions in mouse models. Regulatory T cells (Treg cells) have been shown to be responsible for this UVB-induced suppression of CHS. The epidermal growth factor (EGF)-like growth factor amphiregulin (AREG) engages EGFR on Treg cells and, in different disease models, it was shown that mast cell-derived AREG is essential for optimal Treg cell function in vivo. Here we determined whether AREG has a role in UVB-induced, Treg cell-mediated suppression of CHS reactions in the skin. Our data show that AREG is essential for UVB-induced CHS suppression. In contrast to the general assumption, however, mast cells were dispensable for UVB-induced immune suppression, whereas basophil-derived AREG was essential. These data reveal, to our knowledge, a previously unreported function for basophils in the homeostasis of immune responses in the skin. Basophils thus fulfill a dual function: they contribute to the initiation of effective type 2 immune responses and, by enhancing the suppressive capacity of local Treg cell populations, also to local immune regulation in the skin. PMID:25089660

  11. 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.

  12. Suppression effects on musical and verbal memory.

    PubMed

    Schendel, Zachary A; Palmer, Caroline

    2007-06-01

    Three experiments contrasted the effects of articulatory suppression on recognition memory for musical and verbal sequences. In Experiment 1, a standard/comparison task was employed, with digit or note sequences presented visually or auditorily while participants remained silent or produced intermittent verbal suppression (saying "the") or musical suppression (singing "la"). Both suppression types decreased performance by equivalent amounts, as compared with no suppression. Recognition accuracy was lower during suppression for visually presented digits than during that for auditorily presented digits (consistent with phonological loop predictions), whereas accuracy was equivalent for visually presented notes and auditory tones. When visual interference filled the retention interval in Experiment 2, performance with visually presented notes but not digits was impaired. Experiment 3 forced participants to translate visually presented music sequences by presenting comparison sequences auditorily. Suppression effects for visually presented music resembled those for digits only when the recognition task required sensory translation of cues. PMID:17848022

  13. 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.

  14. 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.

  15. 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

  16. Dihydroxyselenolane (DHS) supplementation improves survival following whole-body irradiation (WBI) by suppressing tissue-specific inflammatory responses.

    PubMed

    Kunwar, Amit; Verma, Prachi; Bhilwade, H N; Iwaoka, Michio; Priyadarsini, K Indira

    2016-09-01

    Dihydroxyselenolane (DHS), a simple water-soluble organoselenium compound, was evaluated for radioprotection in BALB/c mice after whole-body irradiation (WBI) (8Gy (60)Co, 1Gy/min), by monitoring 30-d post-irradiation survival and biochemical/histological changes in radiosensitive organs. Intraperitoneal administration of DHS at 2mg/kg for five consecutive days before irradiation and three times per week during the post-irradiation period showed maximum benefit (40% improvement in 30 d post-irradiation survival). DHS treatment, despite inducing expression of glutathione peroxidases (GPx1, GPx2, and GPx4) in spleen and intestine, did not protect against radiation-induced acute (10-day) haematopoietic and gastrointestinal toxicities. DHS treatment significantly reduced radiation-induced DNA damage in peripheral leukocytes and inflammatory responses in intestine, lung, and circulation. The anti-inflammatory effect of DHS was associated with reductions in lipid peroxidation, expression of pro-inflammatory genes such as Icam-1, Ccl-2, and iNos-2, and subsequent infiltration of inflammatory cells. Irradiated mice treated with DHS survived until day 30 post-irradiation and showed restoration of spleen cellularity and intestinal villi, but had moderately increased systemic and tissue-specific inflammatory responses. Another organoselenium compound, selenomethionine, evaluated in parallel with DHS at the same dose and treatment schedule, showed comparable radioprotective effects. The mechanism of radioprotection by DHS is mainly via suppression of inflammatory responses. PMID:27542713

  17. 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.

  18. 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.

  19. Pterostilbene suppressed irradiation-resistant glioma stem cells by modulating GRP78/miR-205 axis.

    PubMed

    Huynh, Thanh-Tuan; Lin, Chien-Min; Lee, Wei-Hwa; Wu, Alexander T H; Lin, Yen-Kuang; Lin, Yuh-Feng; Yeh, Chi-Tai; Wang, Liang-Shun

    2015-05-01

    Glioblastoma multiforme (GBM) is the most aggressive type characterized by relapse and resistance even with the combination of radio- and chemotherapy. The presence of glioma stem cells (GSCs) has been shown to contribute to tumorigenesis, recurrence and treatment resistance. Particularly, CD133-positive glioma cells have been shown to represent the subpopulation that confers glioma radioresistance and suggested to be the source of tumor recurrence after radiation. Thus, a better understanding and the development of agents which target GSCs could potentially lead to a significant improvement in treating GBM patients. Here, we demonstrated that GRP78 (an antistress protein) was highly expressed in GBM cells along with β-catenin and Notch and correlated to the development of GSCs. CD133+ GSCs exhibited enhanced migration/invasion and self-renewal abilities. When GRP78 was silenced, GSC properties were suppressed and the sensitivity towards irradiation increased. In addition, the level of microRNA 205 appeared to be negatively associated with GRP78 expression. Our previous study indicated that pterostilbene (PT) possessed anticancer stem cell properties in hepatocellular carcinoma. Thus, we examined whether PT is also effective against GSCs. We found that PT-treated GSCs exhibited suppressed self-renewal and irradiation-resistant abilities. PT-mediated effects were associated with an increase of miR-205. Finally, we showed that PT treatment suppressed tumorigenesis in GSC xenograft mice. In conclusion, we provided evidence that GRP78/miR-205 axis played an important role in GSC maintenance and irradiation resistance. PT treatment suppressed GSC development via negatively modulating GRP78 signaling. PT may be considered for combined therapeutic agent to enhance irradiation efficacy in GBM patients. PMID:25736407

  20. Complete suppression of reverse annealing of neutron radiation damage during active gamma irradiation in MCZ Si detectors

    NASA Astrophysics Data System (ADS)

    Li, Z.; Verbitskaya, E.; Chen, W.; Eremin, V.; Gul, R.; Härkönen, J.; Hoeferkamp, M.; Kierstead, J.; Metcalfe, J.; Seidel, S.

    2013-01-01

    For the development of radiation-hard Si detectors for the SiD BeamCal (Si Detector Beam Calorimeter) program for International Linear Collider (ILC), n-type Magnetic Czochralski Si detectors have been irradiated first by fast neutrons to fluences of 1.5×1014 and 3×1014 neq/cm2, and then by gamma up to 500 Mrad. The motivation of this mixed radiation project is to test the radiation hardness of MCZ detectors that may utilize the gamma/electron radiation to compensate the negative effects caused by neutron irradiation, all of which exists in the ILC radiation environment. By using the positive space charge created by gamma radiation in MCZ Si detectors, one can cancel the negative space charge created by neutrons, thus reducing the overall net space charge density and therefore the full depletion voltage of the detector. It has been found that gamma radiation has suppressed the room temperature reverse annealing in neutron-irradiated detectors during the 5.5 month of time needed to reach a radiation dose of 500 Mrad. The room temperature annealing (RTA) was verified in control samples (irradiated to the same neutron fluences, but going through this 5.5 month RTA without gamma radiation). This suppression is in agreement with our previous predictions, since negative space charge generated during the reverse annealing was suppressed by positive space charge induced by gamma radiation. The effect is that regardless of the received neutron fluence the reverse annealing is totally suppressed by the same dose of gamma rays (500 Mrad). It has been found that the full depletion voltage for the two detectors irradiated to two different neutron fluences stays the same before and after gamma radiation. Meanwhile, for the control samples also irradiated to two different neutron fluences, full depletion voltages have gone up during this period. The increase in full depletion voltage in the control samples corresponds to the generation of negative space charge, and this

  1. Vasopressin Effectively Suppresses Male Fertility

    PubMed Central

    Kwon, Woo-Sung; Park, Yoo-Jin; Kim, Yun-Hee; You, Young-Ah; Kim, In Cheul; Pang, Myung-Geol

    2013-01-01

    Arginine vasopressin (VP) is neurohypophysial hormone has been implicated in stimulating contractile activity of the male reproductive tract in the testis. Higher levels of VP decrease sperm count and motility. However, very little is known about the involvement of VP in controlling mammalian reproductive process. The goal of this study was to confirm that effect of VP receptor (AVPR2) on sperm function in capacitation condition. Deamino [Cys 1, D-ArgS] vasopressin (dDAVP), an AVPR2 agonist that operates only on AVPR2, was used. Also, Mouse spermatozoa were incubated with various concentrations of dDAVP (10−11–10−5 M) and sperm motility, capacitation status, Protein Kinase A activity (PKA), tyrosine phosphorylation, fertilization, and embryo development were assessed using computer-assisted sperm analysis, Combined Hoechst 33258/chlortetracycline fluorescence, Western blotting, and in vitro fertilization, respectively. AVPR2 was placed on the acrosome region and mid-piece in cauda epididymal spermatozoa, but the caput epididymal spermatozoa was mid-piece only. The high dDAVP treatment (10−8 and 10−5 M) significantly decreased sperm motility, intracellular pH and PKA substrates (approximately 55 and 22 kDa) and increased Ca2+ concentration. The highest concentration treatment significantly decreased PKA substrate (approximately 23 kDa) and tyrosine phosphorylation (approximately 30 kDa). VP detrimentally affected capacitation, acrosome reaction, and embryo development. Treatment with the lowest concentration (10−11 M) was not significantly different. Our data have shown that VP stimulates ion transport across sperm membrane through interactions with AVPR2. VP has a detrimental effect in sperm function, fertilization, and embryonic development, suggesting its critical role in the acquisition of fertilizing ability of mouse spermatozoa. These research findings will enable further study to determine molecular mechanism associated with fertility in

  2. 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.

  3. 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.

  4. 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.

  5. Irradiation effects on hydrases for biomedical applications

    NASA Astrophysics Data System (ADS)

    Furuta, Masakazu; Ohashi, Isao; Oka, Masahito; Hayashi, Toshio

    2000-03-01

    To apply an irradiation technique to sterilize "Hybrid" biomedical materials including enzymes, we selected papain, a well-characterized plant endopeptidase as a model to examine durability of enzyme activity under the practical irradiation condition in which limited data were available for irradiation inactivation of enzymes. Dry powder and frozen aqueous solution of papain showed significant durability against 60Co-gamma irradiation suggesting that, the commercial irradiation sterilizing method is applicable without modification. Although irradiation of unfrozen aqueous papain solution showed an unusual change of the enzymatic activity with the increasing doses, and was totally inactivated at 15 kGy, we managed to keep the residual activity more than 50% of initial activity after 30-kGy irradiation, taking such optimum conditions as increasing enzyme concentration from 10 to 100 mg/ml and purging with N 2 gas to suppress the formation of free radicals.

  6. Inhibition of microRNA-155 sensitizes lung cancer cells to irradiation via suppression of HK2-modulated glucose metabolism.

    PubMed

    Lv, Xin; Yao, Li; Zhang, Jianli; Han, Ping; Li, Cuiyun

    2016-08-01

    MicroRNAs (miRNAs) are small non-coding regulatory RNAs, which are involved in the post-transcriptional regulation of gene expression. miRNA (miR)-155, which has previously been reported to be overexpressed in lung cancer, is correlated with poor patient prognosis. The present study aimed to investigate the effects of miR‑155 on the radiosensitivity of human non‑small cell lung cancer (NSCLC) cells. To explore the roles of miRNAs in the regulation of irradiation sensitivity of human lung cancer cells, the expressions of miR‑155 in response to irradiation, have been studied by RT‑qPCR, and the putative direct target of miR‑155 was identified by western blot and luciferase assays. The results of the present study revealed that the expression of miR‑155 was induced by irradiation, thus suggesting a positive correlation between miR‑155 and radiosensitivity. Furthermore, overexpression of miR‑155 rendered lung cancer cells resistant to irradiation. In addition, hexokinase 2 (HK2) was identified as an indirect target of miR‑155; exogenous overexpression of miR‑155 upregulated the expression of HK2, whereas inhibition of miR‑155 by antisense miRNA suppressed HK2 expression. In addition, HK2‑modulated glucose metabolism was significantly upregulated by overexpression of miR‑155. Notably, inhibition of miR‑155 sensitized lung cancer cells to irradiation via suppression of glucose metabolism. In conclusion, the present study reported a novel function for miR‑155 in the regulation of NSCLC cell radiosensitivity, thus suggesting that miR‑155 may be considered a therapeutic target for the development of anticancer drugs. PMID:27315591

  7. Post-irradiation effects in polyethylenes irradiated under various atmospheres

    NASA Astrophysics Data System (ADS)

    Suljovrujic, E.

    2013-08-01

    If a large amount of polymer free radicals remain trapped after irradiation of polymers, the post-irradiation effects may result in a significant alteration of physical properties during long-term shelf storage and use. In the case of polyethylenes (PEs) some failures are attributed to the post-irradiation oxidative degradation initiated by the reaction of residual free radicals (mainly trapped in crystal phase) with oxygen. Oxidation products such as carbonyl groups act as deep traps and introduce changes in carrier mobility and significant deterioration in the PEs electrical insulating properties. The post-irradiation behaviour of three different PEs, low density polyethylene (LDPE), linear low density polyethylene (LLDPE) and high density polyethylene (HDPE) was studied; previously, the post-irradiation behaviour of the PEs was investigated after the irradiation in air (Suljovrujic, 2010). In this paper, in order to investigate the influence of different irradiation media on the post-irradiation behaviour, the samples were irradiated in air and nitrogen gas, to an absorbed dose of 300 kGy. The annealing treatment of irradiated PEs, which can substantially reduce the concentration of free radicals, is used in this study, too. Dielectric relaxation behaviour is related to the difference in the initial structure of PEs (such as branching, crystallinity etc.), to the changes induced by irradiation in different media and to the post-irradiation changes induced by storage of the samples in air. Electron spin resonance (ESR), differential scanning calorimetry (DSC), infra-red (IR) spectroscopy and gel measurements were used to determine the changes in the free radical concentration, crystal fraction, oxidation and degree of network formation, respectively.

  8. Systemic suppression of delayed-type hypersensitivity by supernatants from UV-irradiated keratinocytes. An essential role for keratinocyte-derived IL-10.

    PubMed

    Rivas, J M; Ullrich, S E

    1992-12-15

    Exposing murine keratinocyte cultures to UV radiation causes the release of a suppressive cytokine that mimics the immunosuppressive effects of total-body UV exposure. Injecting supernatants from UV-irradiated keratinocyte cultures into mice inhibits their ability to generate a delayed-type hypersensitivity reaction against allogeneic histocompatibility Ag, and spleen cells from mice injected with supernatant do not respond to alloantigen in the in vitro MLR. A unique feature of the immunosuppression induced by either total-body UV-exposure or injecting the suppressive cytokine from UV-irradiated keratinocytes is the selectivity of suppression. Although cellular immune reactions such as delayed-type hypersensitivity are suppressed antibody production is unaffected. Because the selective nature to the UV-induced immunosuppression is similar to the biologic activity of IL-10, we examined the hypothesis that UV exposure of keratinocytes causes the release of IL-10. Keratinocyte monolayers were exposed to UV radiation and at specific times after exposure mRNA was isolated or the culture supernatant from the cells was collected. IL-10 mRNA expression was enhanced in UV-irradiated keratinocytes. The secretion of IL-10 by the irradiated keratinocytes was determined by Western blot analysis. A band reactive with anti-IL-10 mAb was found in supernatants from the UV-irradiated but not the mock-irradiated cells. IL-10 biologic activity was determined by the ability of the supernatants from the UV-irradiated keratinocytes to suppress IFN-gamma production by Ag-activated Th 1 cell clones. Anti-IL-10 mAb neutralized the ability of supernatants from UV-irradiated keratinocytes to suppress the induction of delayed-type hypersensitivity in vivo. Furthermore, injecting UV-irradiated mice with antibodies against IL-10 partially inhibited in vivo immunosuppression. These data indicate that activated keratinocytes are capable of secreting IL-10 and suggest that the release of IL-10 by

  9. Effective rapid airframe suppression evaluation (ERASE)

    NASA Astrophysics Data System (ADS)

    Engelhardt, Michel

    1993-08-01

    This paper presents an analytical method to effectively and rapidly evaluate the impact of airframe suppression on electro-optical/infrared (E-O/IR) system lock-on range. This method is known as the Effective Rapid Airframe Suppression Evaluation (ERASE). It can be used to perform tradeoff analyses with respect to IR suppression systems and evaluate the impact of these systems on E-O/IR systems. This paper discusses a new set of dimensionless equations and how these equations are used to evaluate changes in airframe area, temperature, emissivity, and reflectivity (as a function of earthshine, solar reflections, and skyshine). Since the ERASE code has been formulated as a rapid computational tool (capable of generating over 1000 design variations in minutes), it is ideal for performing design tradeoffs against airframe shaping, thermal control systems, and diffuse reflectivity/emissivity control. Results from the ERASE code are presented using Grumman's System for IR Evaluation/Contrast Generator Code (SIRE/CONGEN) as input.

  10. Observation of Gamma Irradiation-Induced Suppression of Reversed Annealing in Neutron Irradiated MCZ Si Detectors

    SciTech Connect

    Li, Z.; Gul, R.; Harkonen, J.; Kierstead, J.; Metcalfe, J.; Seidel, S.

    2009-02-06

    For the development of radiation-hard Si detectors for the SiD BeamCal program for the future ILC (International Linear Collider), n-type MCZ Si detectors have been irradiated first by fast neutrons to flueneces of 1.5 x 1014 and 3 x 1014 neq/cm2, and then by gamma up to 500 Mrad. The motivation of this mixed radiation project is to develop a Si detector that can utilize the gamma/electron radiation that exists in the ICL radiation environment, which also includes neutrons. By using the positive space charge (SC) created by gamma radiation in MCZ Si detectors, one can cancel the negative space charge created by neutrons, thus reducing the overall/net space charge density and therefore the full depletion voltage of the detector.

  11. 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. PMID:26648389

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

    SciTech Connect

    Deng, Hongxiang; Zu, Xiaotao; Zheng, WG; Yuan, XD; Xiang, Xia; Sun, Kai; Gao, Fei

    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.

  13. 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.

  14. Irradiation effects in ferritic steels

    NASA Astrophysics Data System (ADS)

    Lechtenberg, Thomas

    1985-08-01

    Since 1979 the Alloy Development for Irradiation Performance (ADIP) task funded by the US Department of Energy has been studying the 2-12Cr class of ferritic steels to establish the feasibility of using them in fusion reactor first wall/breeding blanket (FW/B) applications. The advantages of ferritic steels include superior swelling resistance, low thermal stresses compared to austenitic stainless steels, attractive mechanical properties up to 600°C. and service histories exceeding 100 000 h. These steels are commonly used in a range of microstructural conditions which include ferritic, martensitic. tempered martensitic, bainitic etc. Throughout this paper where the term "ferritic" is used it should be taken to mean any of these microstructures. The ADIP task is studying several candidate alloy systems including 12Cr-1MoWV (HT-9), modified 9Cr-1MoVNb, and dual-phased steels such as EM-12 and 2 {1}/{4}Cr-Mo. These materials are ferromagnetic (FM), body centered cubic (bcc), and contain chromium additions between 2 and 12 wt% and molybdenum additions usually below 2%. The perceived issues associated with the application of this class of steel to fusion reactors are the increase in the ductile-brittle transition temperature (DBTT) with neutron damage, the compatibility of these steels with liquid metals and solid breeding materials, and their weldability. The ferromagnetic character of these steels can also be important in reactor design. It is the purpose of this paper to review the current understanding of these bcc steels and the effects of irradiation. The major points of discussion will be irradiation-induced or -enhanced dimensional changes such as swelling and creep, mechanical properties such as tensile strength and various measurements of toughness, and activation by neutron interactions with structural materials.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Suppression on Your Own Terms: Internally Generated Displays of Craving Suppression Predict Rebound Effects

    PubMed Central

    Sayers, W. Michael; Sayette, Michael A.

    2015-01-01

    Research on emotion suppression has shown a rebound effect, in which expression of the targeted emotion increases following a suppression attempt. In prior investigations, participants have been explicitly instructed to suppress their responses, which has drawn the act of suppression into metaconsciousness. Yet emerging research emphasizes the importance of nonconscious approaches to emotion regulation. This study is the first in which a craving rebound effect was evaluated without simultaneously raising awareness about suppression. We aimed to link spontaneously occurring attempts to suppress cigarette craving to increased smoking motivation assessed immediately thereafter. Smokers (n = 66) received a robust cued smoking-craving manipulation while their facial responses were videotaped and coded using the Facial Action Coding System. Following smoking-cue exposure, participants completed a behavioral choice task previously found to index smoking motivation. Participants evincing suppression-related facial expressions during cue exposure subsequently valued smoking more than did those not displaying these expressions, which suggests that internally generated suppression can exert powerful rebound effects. PMID:23842957

  20. 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.

  1. Effects of suppression and appraisals on thought frequency and distress.

    PubMed

    Corcoran, Kathleen M; Woody, Sheila R

    2009-12-01

    Cognitive theories of obsessions highlight appraisals of personal significance and thought suppression in the development and maintenance of intrusive thoughts. The current study examined the role of personal significance within the context of a thought suppression paradigm. The primary aim was to examine whether suppression would have differential effects for target thoughts appraised as personally meaningful versus relatively unimportant. A blasphemous thought served as the target thought, and highly religious and nonreligious participants were recruited. Participants completed a two-interval thought suppression task; during interval 1 they were randomly assigned to suppress or not suppress the target thought and during interval 2, all participants were given "do not suppress" instructions. Suppression resulted in sustained frequency of thoughts in contrast to the decline in thought frequency observed for non-suppression. Differential effects of suppression were found across the two groups. Moreover, suppression was associated with increased negative mood and anxiety. Results suggest that suppression of personally meaningful thoughts is a counterproductive strategy. PMID:19765684

  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. 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

  4. Effects of irradiation on mandibular scintigraphy

    SciTech Connect

    Aitasalo, K.; Ruotsalainen, P.

    1985-11-01

    Technetium-99m methylene diphosphonate (Sn) scintigraphy with computer analysis was used to investigate alterations in the pathophysiology of the normal mandible and the pathologic mandible during and after irradiation. Slight but significant elevations of uptake levels were recorded as an early effect of irradiation. The elevations correlated with the duration of treatment and normalized over a follow-up period of 6 to 12 mo. Increased mandibular metabolism was found during irradiation and in osteomyelitis and osteoradionecrosis of the mandible. Scintigraphy with computer analysis proved a simple and valid method in the evaluation of early irradiation damage and pathophysiologic conditions of the mandible. The method can also be used to predict whether the irradiation damage will become irreversible.

  5. Suppression of initial imprinting of laser nonuniformity with x-ray pre-irradiation

    NASA Astrophysics Data System (ADS)

    Shiraga, H.; Azechi, H.; Nakai, M.; Miyanaga, N.; Nishimura, H.; Shigemori, K.; Kato, Y.; Yamanaka, T.; Murakami, M.; Takabe, H.; Nishihara, K.; Mima, K.; Endo, T.

    1996-11-01

    We examined a new scheme called indirect-direct hybrid irradiation and experimentally demonstrated its effect in reducing the initial imprinting of the laser beam nonuniformity. Surface perturbation of a planer target seeded by the initial imprinting due to imposed intensity modulation of 10% with the wavelength of 100 μm in the foot pulse beam (1x10^13W/cm^2)was amplified with linear RT instability in the following acceleration phase driven by the main drive beam(1x10^14W/cm^2). Growth of resulting areal mass density perturbation was observed clearly with streaked face-on x-ray backlit image. When another gold plate was set beside the sample foil and was irradiated with a separate beam 0.4 ns prior to the foot pulse to pre-irradiate the target with x-rays(1x10^11W/cm^2), the modulation was reduced to 60% of the normal case. Observed smoothing effect is explained by the enhanced cloudy-day effect. Several types of the target configuration are designed and being examined to realize the indirect/direct-hybrid-drive spherical implosion.

  6. Effect of intermittent irrigation on rice productivity and weed suppression

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Certain indica rice lines from Asia have been shown to suppress barnyardgrass (Echinochloa crus-galli) effectively in conventional flood-irrigated (FLI) production systems, but their weed suppression potential in “intermittent flood-irrigated” (IFI) production systems is unknown. IFI systems (aka “...

  7. 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. PMID:26238154

  8. 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 cluster 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.

  9. Evaluation of irradiation effects on concrete structure

    SciTech Connect

    Kontani, O.; Ishizawa, A.; Maruyama, I.; Takizawa, M.; Sato, O.

    2012-07-01

    In assessing the soundness of irradiated concrete of nuclear power plants operated for more than 30 years, reference levels are employed: 1x10{sup 20} n/cm{sup 2} for fast neutrons and 2x10{sup 10} rad (2x10{sup 5} kGy) for gamma rays. Concrete structures are regarded as sound when the estimated irradiance levels after 60 years of operation are less than the reference levels. The reference levels were obtained from a paper by Hilsdorf. It was found, however, that the test conditions in which data were obtained by the researchers referred in that paper are very different from the irradiation and heat conditions usually found in a Light Water Reactor (LWR), and therefore aren't appropriate for assessing the soundness of irradiated concrete of an LWR. This paper investigates the interactions between radiation and concrete and presents the results of gamma ray irradiation tests on cement paste samples in order to provide a better understanding of the irradiation effects on concrete. (authors)

  10. The effects of irradiation on blood components

    SciTech Connect

    Button, L.N.; DeWolf, W.C.; Newburger, P.E.; Jacobson, M.S.; Kevy, S.V.

    1981-01-01

    The functional properties of formed elements of whole blood were studied following irradiation doses of 500 to 20,000 rads. Irradiated lymphocytes retained only 1.5 per cent of their 3H thymidine uptake after a 5,000-rad exposure and none after 7,500 rads. Red blood cells stored for 21 days and then irradiated with 5,000 rads had the same survival as nonirradiated controls. In contrast, 5,000 rads reduced platelet yields. However, transfused irradiated platelets produced the expected increases in platelet counts and controlled hemostasis in thrombocytopenic patients. After 5,000 rads, granulocytes had normal bacterial killing capacity, chemotactic mobility, and normal superoxide production after high-dose stimulation. Nitroblue tetrazolium reduction and ingestion stimulated by complement opsonized oil droplets were not diminished by 5,000- and 10,000-rad irradiation. The functional qualities of cellular blood components other than lymphocytes are not compromised by 5,000 rads. This irradiation dose may be an effective means of controlling incidence of graft-vs-host disease in immunosuppressed patients.

  11. When thought suppression backfires: its moderator effect on eating psychopathology.

    PubMed

    Ferreira, Cláudia; Palmeira, Lara; Trindade, Inês A; Catarino, Francisca

    2015-09-01

    Recently, several studies have pointed the importance of thought suppression as a form of experiential avoidance in different psychopathological conditions. Thought suppression may be conceptualized as an attempt to decrease or eliminate unwanted internal experiences. However, it encloses a paradoxical nature, making those thoughts hyper accessible and placing an extra burden on individuals. This avoidance process has been associated with several psychopathological conditions. However, its role in eating psychopathology remains unclear. The present study aims to explore the moderation effect of thought suppression on the associations between body image-related unwanted internal experiences (unfavorable social comparison through physical appearance and body image dissatisfaction) and eating psychopathology severity in a sample of 211 female students. Correlational analyses showed that thought suppression is associated with psychological inflexibility and eating disorders' main risk factors and symptoms. Moreover, two independent analyses revealed that thought suppression moderates, as it amplifies, the impact of unfavorable social comparisons through physical appearance (model 1) and body image dissatisfaction (model 2) on disordered eating attitudes and behaviors. Hence, for the same level of these body-related internal experiences, young females who reveal higher levels of thought suppression present higher eating psychopathology. Taken together, these findings highlight the key role of thought suppression in eating psychopathology and present important clinical implications. PMID:25663280

  12. Enhancement effect of irradiation by methotrexate

    SciTech Connect

    Shehata, W.M.; Meyer, R.L.

    1980-09-15

    Three cases are described in which complications developed which were believed to be due to the enhancement effect of irradiation by methotrexate during the course of therapy for lung, kidney, and bladder cancer. These included esophageal and large bowel complications. In two of these cases, the patients improved with conservative therapy.

  13. Ion irradiation effects on metallic nanocrystals

    NASA Astrophysics Data System (ADS)

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

    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 SiO2. 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/SiO2 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.

  14. 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.

  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. 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

  17. 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.

  18. Evaluating the Effectiveness of Infrared Signature Suppression of Aircraft Skin

    NASA Astrophysics Data System (ADS)

    Lu, Jian Wei; Wang, Qiang; Kwon, Oh Joon

    During typical supersonic cruising, the temperature of the aircraft skin rises above 300 K due to aerodynamic heating. In this situation, aircraft-skin infrared (IR) suppression, used to minimize the radiation contrast from the background is a crucial survival technology. In the present study, a technique to evaluate the effectiveness of IR suppression of aircraft skin is proposed. For this purpose, a synthetic procedure based on numerical simulations has been developed. In this procedure, the thermal status of aircraft skin is obtained using a computational fluid dynamics (CFD) method for complex aircraft geometries. An IR signature model is proposed using a reverse Monte Carlo (RMC) technique. The detection range and the IR contrast are adopted as the performance indicators for the evaluation of the aircraft IR suppression. The influence of these factors related to the aircraft-skin radiation, such as aircraft-skin emissivity, surface temperature distribution and flight speed, on the IR contrast and the detection range is also studied. As a test case, the effectiveness of various IR suppression schemes was analyzed for a typical air combat situation. Then, the method is applied to clarify the contribution of each aircraft component to the IR suppression of the overall IR radiation. The results show that aircraft-skin temperature control and emissivity control are effective means to reduce the IR radiation and to achieve lower detection. The results can be used as a practical guide for designing future stealth aircraft.

  19. Cholesterol suppresses antimicrobial effect of statins

    PubMed Central

    Haeri, Mohammad Reza; White, Kenneth; Qharebeglou, Mohammad; Ansar, Malek Moein

    2015-01-01

    Objective(s): Isoprenoid biosynthesis is a key metabolic pathway to produce a wide variety of biomolecules such as cholesterol and carotenoids, which target cell membranes. On the other hand, it has been reported that statins known as inhibitors of isoprenoid biosynthesis and cholesterol lowering agents, may have a direct antimicrobial effect on the some bacteria. The exact action of statins in microbial metabolism is not clearly understood. It is possible that statins inhibit synthesis or utilization of some sterol precursor necessary for bacterial membrane integrity. Accordingly, this study was designed in order to examine if statins inhibit the production of a compound, which can be used in the membrane, and whether cholesterol would replace it and rescue bacteria from toxic effects of statins. Materials and Methods: To examine the possibility we assessed antibacterial effect of statins with different classes; lovastatin, simvastatin, and atorvastatin, alone and in combination with cholesterol on two Gram-positive (Staphylococcus aureus and Enterococcus faecalis) and two Gram-negative (Pseudomonas aeruginosa and Escherichia coli) bacteria using gel diffusion assay. Results: Our results showed that all of the statins except for lovastatin had significant antibacterial property in S. aureus, E. coli, and Enter. faecalis. Surprisingly, cholesterol nullified the antimicrobial action of effective statins in statin-sensitive bacteria. Conclusion: It is concluded that statins may deprive bacteria from a metabolite responsible for membrane stability, which is effectively substituted by cholesterol. PMID:26877857

  20. 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.

  1. Effects of phosphorus, silicon and sulphur on microstructural evolution in austenitic stainless steels during electron irradiation

    NASA Astrophysics Data System (ADS)

    Fukuya, K.; Nakahigashi, S.; Ozaki, S.; Shima, S.

    1991-03-01

    Fe-18Cr-9Ni-1.5Mn austenitic alloys containing phosphorus, silicon and sulphur were irradiated by 1 MeV electrons at 573-773 K. Phosphorus increased the intersitial loop nucleation and decreased the void swelling by increasing void number density and suppressing void growth. Silicon had a similar effect to phosphorus but its effect was weaker than phosphorus. Sulphur enhanced void swelling through increasing the void density. Nickel enrichment at grain boundaries was suppressed only in the alloy containing phosphorus. These phosphorus effects may be explained by a strong interaction with interstitials resulting in a high density of sinks for point defects.

  2. Protease inhibitors suppress the survival increase mediated by uncouplers in X-irradiated mammalian cells.

    PubMed

    Michel, S; Laval, F

    1982-01-01

    When mammalian cells are incubated with an uncoupler of oxidative phosphorylation prior to and during X-irradiation, the survival and the mutation frequency are markedly increased. This process requires protein synthesis and is inhibited when the cells are plated in the presence of a protease inhibitor (antipain or leupeptin). These results suggest the existence of an error-prone DNA repair process in X-irradiated mammalian cells. PMID:6814524

  3. Effects and consequences of prenatal irradiation.

    PubMed

    Vos, O

    1989-06-01

    After a brief introduction about the historic development of risk estimates and maximum permissible doses of ionizing radiation, the risks of prenatal irradiation are discussed. Experimental data mainly obtained with mice indicate that the most important risk exists during the period of organogenesis and concerns the induction of malformations. Although in man this period lies between about 10 and 80 days after fertilization for most organs, the main development of the brain occurs later, namely between the 8th and 15th week after conception. Data from Japanese victims of the atomic bomb explosions above Hiroshima and Nagasaki indicate that during development the brain is the most sensitive organ to irradiation and maximal sensitivity is found between the 8th and 15th week after fertilization. A dose of one Gray received during this period induces a severe mental retardation in about 45% of the newborns. The dose response relationship is not significantly different from a linear one without a threshold dose. Studies of intelligence and school performance have shown that 1 Gray received during the 8th-15th week causes a shift of the average intelligence of about 30 points. Irradiation before the 8th week and after the 25th week had no effect on intelligence or mental retardation. During the 16th and 25th week sensitivity was about one fourth of that during the 8th-15th week. Although the irradiation of the embryo and fetus should be avoided as much as possible, the new data have led to an abandonment of the so-called 10-day rule. Generally an accidental irradiation of the embryo or fetus of less than 5 cGy is not considered as a medical indication for abortion. Retrospective studies showed that mothers from children who died from leukemia or other childhood tumors, had been subjected to a diagnostic irradiation of the pelvis or lower abdomen more frequently than mothers from children that did not develop a tumor. It has been estimated that prenatal sensitivity for

  4. SUPPRESSION OF DIELECTRONIC RECOMBINATION DUE TO FINITE DENSITY EFFECTS

    SciTech Connect

    Nikolic, D.; Gorczyca, T. W.; Korista, K. T.; Ferland, G. J.; Badnell, N. R.

    2013-05-01

    We have developed a general model for determining density-dependent effective dielectronic recombination (DR) rate coefficients in order to explore finite-density effects on the ionization balance of plasmas. Our model consists of multiplying by a suppression factor those highly-accurate total zero-density DR rate coefficients which have been produced from state-of-the-art theoretical calculations and which have been benchmarked by experiment. The suppression factor is based upon earlier detailed collision-radiative calculations which were made for a wide range of ions at various densities and temperatures, but used a simplified treatment of DR. A general suppression formula is then developed as a function of isoelectronic sequence, charge, density, and temperature. These density-dependent effective DR rate coefficients are then used in the plasma simulation code Cloudy to compute ionization balance curves for both collisionally ionized and photoionized plasmas at very low (n{sub e} = 1 cm{sup -3}) and finite (n{sub e} = 10{sup 10} cm{sup -3}) densities. We find that the denser case is significantly more ionized due to suppression of DR, warranting further studies of density effects on DR by detailed collisional-radiative calculations which utilize state-of-the-art partial DR rate coefficients. This is expected to impact the predictions of the ionization balance in denser cosmic gases such as those found in nova and supernova shells, accretion disks, and the broad emission line regions in active galactic nuclei.

  5. 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.

  6. Irradiation effects on polymer-model compounds

    NASA Astrophysics Data System (ADS)

    Seguchi, Tadao; Katsumura, Yosuke; Hayashi, Nariyuki; Hayakawa, Naohiro; Tamura, Naoyuki; Tabata, Yoneho

    Irradiation effects on n-paraffins and squalane, used as models of polymers, were investigated by product analysis. Four n-paraffins, C 20H 42, C 21H 44, C 23H 48 and C 24H 50, and squalane (C 30H 62) were γ-irradiated under vacuum in liquid, crystalline and glassy states. The evolved gases were analyzed by gas chromatography and changes in molecular weight were analyzed by liquid chromatography and mass spectroscopy. G-values for crosslinking of n-paraffins were 1.2 for crystalline states (at 25°C) and 1.7 for liquid states (at 55°C), and showed no difference between odd and even carbon numbers. The G-value of liquid squalane was 1.7; it was 1.3 for the glassy state at low temperature (-77°C). Double bonds were common in the crosslinked products, especially after liquid-phase irradiation. The probability of chain scission was estimated as being negligible, though a small number of chain-scission products (which were products of scission at chain-ends or side chains) were observed by gas analysis.

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

    PubMed Central

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

    2016-01-01

    ABSTRACT 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 HdhQ111 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. PMID:27141414

  8. Effects of silicon, carbon and molybdenum additions on IASCC of neutron irradiated austenitic stainless steels

    NASA Astrophysics Data System (ADS)

    Nakano, J.; Miwa, Y.; Kohya, T.; Tsukada, T.

    2004-08-01

    To study the effects of minor elements on irradiation assisted stress corrosion cracking (IASCC), high purity type 304 and 316 stainless steels (SSs) were fabricated and minor elements, Si or C were added. After neutron irradiation to 3.5 × 10 25 n/m 2 ( E>1 MeV), slow strain rate tests (SSRTs) of irradiated specimens were conducted in oxygenated high purity water at 561 K. Specimen fractured surfaces were examined using a scanning electron microscope (SEM) after the SSRTs. The fraction of intergranular stress corrosion cracking (IGSCC) on the fractured surface after the SSRTs increased with neutron fluence. In high purity SS with added C, the fraction of IGSCC was the smallest in the all SSs, although irradiation hardening level was the largest of all the SSs. Addition of C suppressed the susceptibility to IGSCC.

  9. 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.

  10. 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

  11. Effects of carbon ion irradiation and X-ray irradiation on the ubiquitylated protein accumulation.

    PubMed

    Isozaki, Tetsuro; Fujita, Mayumi; Yamada, Shigeru; Imadome, Kaori; Shoji, Yoshimi; Yasuda, Takeshi; Nakayama, Fumiaki; Imai, Takashi; Matsubara, Hisahiro

    2016-07-01

    C-ion radiotherapy is associated with improved local control and survival in several types of tumors. Although C-ion irradiation is widely reported to effectively induce DNA damage in tumor cells, the effects of irradiation on proteins, such as protein stability or degradation in response to radiation stress, remain unknown. We aimed to compare the effects of C-ion and X-ray irradiation focusing on the cellular accumulation of ubiquitylated proteins. Cells from two human colorectal cancer cell lines, SW620 and SW480, were subjected to C-ion or X-ray irradiation and determination of ubiquitylated protein levels. High levels of ubiquitylated protein accumulation were observed in the C-ion-irradiated SW620 with a peak at 3 Gy; the accumulation was significantly lower in the X-ray-irradiated SW620 at all doses. Enhanced levels of ubiquitylated proteins were also detected in C-ion or X-ray-irradiated SW480, however, those levels were significantly lower than the peak detected in the C-ion-irradiated SW620. The levels of irradiation-induced ubiquitylated proteins decreased in a time-dependent manner, suggesting that the proteins were eliminated after irradiation. The treatment of C-ion-irradiated SW620 with a proteasome inhibitor (epoxomicin) enhanced the cell killing activity. The accumulated ubiquitylated proteins were co-localized with γ-H2AX, and with TP53BP1, in C-ion-irradiated SW620, indicating C-ion-induced ubiquitylated proteins may have some functions in the DNA repair system. Overall, we showed C-ion irradiation strongly induces the accumulation of ubiquitylated proteins in SW620. These characteristics may play a role in improving the therapeutic ratio of C-ion beams; blocking the clearance of ubiquitylated proteins may enhance sensitivity to C-ion radiation. PMID:27175736

  12. Effects of carbon ion irradiation and X-ray irradiation on the ubiquitylated protein accumulation

    PubMed Central

    ISOZAKI, TETSURO; FUJITA, MAYUMI; YAMADA, SHIGERU; IMADOME, KAORI; SHOJI, YOSHIMI; YASUDA, TAKESHI; NAKAYAMA, FUMIAKI; IMAI, TAKASHI; MATSUBARA, HISAHIRO

    2016-01-01

    C-ion radiotherapy is associated with improved local control and survival in several types of tumors. Although C-ion irradiation is widely reported to effectively induce DNA damage in tumor cells, the effects of irradiation on proteins, such as protein stability or degradation in response to radiation stress, remain unknown. We aimed to compare the effects of C-ion and X-ray irradiation focusing on the cellular accumulation of ubiquitylated proteins. Cells from two human colorectal cancer cell lines, SW620 and SW480, were subjected to C-ion or X-ray irradiation and determination of ubiquitylated protein levels. High levels of ubiquitylated protein accumulation were observed in the C-ion-irradiated SW620 with a peak at 3 Gy; the accumulation was significantly lower in the X-ray-irradiated SW620 at all doses. Enhanced levels of ubiquitylated proteins were also detected in C-ion or X-ray-irradiated SW480, however, those levels were significantly lower than the peak detected in the C-ion-irradiated SW620. The levels of irradiation-induced ubiquitylated proteins decreased in a time-dependent manner, suggesting that the proteins were eliminated after irradiation. The treatment of C-ion-irradiated SW620 with a proteasome inhibitor (epoxomicin) enhanced the cell killing activity. The accumulated ubiquitylated proteins were co-localized with γ-H2AX, and with TP53BP1, in C-ion-irradiated SW620, indicating C-ion-induced ubiquitylated proteins may have some functions in the DNA repair system. Overall, we showed C-ion irradiation strongly induces the accumulation of ubiquitylated proteins in SW620. These characteristics may play a role in improving the therapeutic ratio of C-ion beams; blocking the clearance of ubiquitylated proteins may enhance sensitivity to C-ion radiation. PMID:27175736

  13. 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

  14. Sequential analysis of the numerical Stroop effect reveals response suppression.

    PubMed

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

    2011-09-01

    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, response repetition), however, is less understood. In the current experiment we used the numerical Stroop paradigm, in which the processing of irrelevant numerical values of 2 digits interferes with the processing of their physical size, to pinpoint the precise level of the suppression. Using a sequential analysis, we dissociated perceptual repetition from response repetition of the relevant and irrelevant dimension. Our analyses of reaction times, error rates, and diffusion modeling revealed that the congruity effect is significantly reduced or even absent when the response sequence of the irrelevant dimension, rather than the numerical value or the physical size, is repeated. These results suggest that automatic activation of the irrelevant dimension is suppressed at the response level. The current results shed light on the level of interaction between numerical magnitude and physical size as well as the effect of variability of responses and stimuli on automatic processing. PMID:21500951

  15. 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.

  16. 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. PMID:20433090

  17. The Unreasonable Effectiveness of Exponentially Suppressed Corrections in Preserving Information

    NASA Astrophysics Data System (ADS)

    Papadodimas, Kyriakos; Raju, Suvrat

    2013-11-01

    We point out that nonperturbative effects in quantum gravity are sufficient to reconcile the process of black hole evaporation with quantum mechanics. In ordinary processes, these corrections are unimportant because they are suppressed by e-S. However, they gain relevance in information-theoretic considerations because their small size is offset by the corresponding largeness of the Hilbert space. In particular, we show how such corrections can cause the von Neumann entropy of the emitted Hawking quanta to decrease after the Page time, without modifying the thermal nature of each emitted quantum. Second, we show that exponentially suppressed commutators between operators inside and outside the black hole are sufficient to resolve paradoxes associated with the strong subadditivity of entropy without any dramatic modifications of the geometry near the horizon.

  18. 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).

  19. Effects of X irradiation on angiogenesis

    SciTech Connect

    Prionas, S.D.; Kowalski, J.; Fajardo, L.F.; Kaplan, I.; Kwan, H.H.; Allison, A.C. )

    1990-10-01

    We have evaluated the effect of X irradiation on the mesenchymal tissue growth (blood capillaries and stromal cells) in an angiogenesis system in the mouse. This was accomplished by implanting a polyvinyl alcohol sponge disc in the subcutis of the thorax, and quantifying the extent of growth reduction of capillaries and stromal cells following graded doses of X rays. The sponge disc contained a centrally located pellet impregnated with 20 micrograms of epidermal growth factor and coated with a thin film of slow-releasing compound. Total growth of vessels and fibroblasts was determined by morphometric analysis of histologic sections. The incorporation of ({sup 3}H)TdR was measured during a 24-h period. A dose-response relationship was observed when X irradiation was given on Day 11 after implantation, with the disc removed on Day 20. A single dose of 15 Gy reduced both the rate of incorporation of ({sup 3}H)TdR and the total growth area. These and previous observations point to endothelial cells as important targets of ionizing radiation in the stroma, especially during the period of active proliferation of these cells, induced by growth factors.

  20. 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. PMID:1199681

  1. Silicon/HfO2 interface: Effects of gamma irradiation

    NASA Astrophysics Data System (ADS)

    Maurya, Savita

    2016-05-01

    Quality of MOS devices is a strong function of substrate and oxide interface. In this work we have studied how gamma photon irradiation affects the interface of a 13 nm thick, atomic layer deposited hafnium dioxide deposited on silicon wafer. CV and GV measurements have been done for pristine and irradiated samples to quantify the effect of gamma photon irradiation. Gamma photon irradiation not only introduces positive charge in the oxide and at the interface of Si/HfO2 interface but also induce phase change of oxide layer. Maximum oxide capacitances are affected by gamma photon irradiation.

  2. 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

  3. 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.

  4. Investigation of the effect of some irradiation parameters on the response of various types of dosimeters to electron irradiation

    NASA Astrophysics Data System (ADS)

    Farah, K.; Kuntz, F.; Kadri, O.; Ghedira, L.

    2004-09-01

    Several undyed and dyed polymer films are commercially available for dosimetry in intense radiation fields, especially for radiation processing of food and sterilisation of medical devices. The effects of temperature during irradiation and post-irradiation stability, on the response of these dosimeters are of importance to operators of irradiation facilities. The present study investigates the effects of temperature during irradiation by 2.2 MeV electrons beam accelerator and post irradiation storage on the response of several types of dosimeter films. All dosimeters showed a significant effect of temperature during irradiation and post-irradiation storage.

  5. Inverse magnetocaloric effect in Ce(Fe{sub 0.96}Ru{sub 0.04}){sub 2}: Effect of fast neutron irradiation

    SciTech Connect

    Dube, V.; Mishra, P. K.; Prajapat, C. L.; Singh, M. R.; Ravikumar, G.; Rajarajan, A. K.; Sastry, P. U.; Thakare, S. V.

    2013-02-05

    We have shown the effect of fast neutron irradiation on the magnetic phase transition and magnetocaloric effect (MCE) in a doped Ce(Fe{sub 0.96}Ru{sub 0.04}){sub 2}, intermettalic. We show that this leads to suppression of MCE and a to a disordered ferromagnetic phase.

  6. Effects of mean flow on duct mode optimum suppression rates

    NASA Technical Reports Server (NTRS)

    Kraft, R. E.; Wells, W. R.

    1976-01-01

    The nature of the solution to the convected acoustic wave equation and associated boundary conditions for rectangular ducts containing uniform mean flow is examined in terms of the complex mapping between the wall admittance and characteristic mode eigenvalues. It is shown that the Cremer optimum suppression criteria must be modified to account for the effects of flow below certain critical values of the nondimensional frequency parameter of duct height divided by sound wavelength. The implications of these results on the design of low frequency suppressors are considered.

  7. Optimal measurement strategies for effective suppression of drift errors.

    PubMed

    Yashchuk, Valeriy V

    2009-11-01

    Drifting of experimental setups with change in temperature or other environmental conditions is the limiting factor of many, if not all, precision measurements. The measurement error due to a drift is, in some sense, in-between random noise and systematic error. In the general case, the error contribution of a drift cannot be averaged out using a number of measurements identically carried out over a reasonable time. In contrast to systematic errors, drifts are usually not stable enough for a precise calibration. Here a rather general method for effective suppression of the spurious effects caused by slow drifts in a large variety of instruments and experimental setups is described. An analytical derivation of an identity, describing the optimal measurement strategies suitable for suppressing the contribution of a slow drift described with a certain order polynomial function, is presented. A recursion rule as well as a general mathematical proof of the identity is given. The effectiveness of the discussed method is illustrated with an application of the derived optimal scanning strategies to precise surface slope measurements with a surface profiler. PMID:19947751

  8. Optimal measurement strategies for effective suppression of drift errors

    SciTech Connect

    Yashchuk, Valeriy V.

    2009-04-16

    Drifting of experimental set-ups with change of temperature or other environmental conditions is the limiting factor of many, if not all, precision measurements. The measurement error due to a drift is, in some sense, in-between random noise and systematic error. In the general case, the error contribution of a drift cannot be averaged out using a number of measurements identically carried out over a reasonable time. In contrast to systematic errors, drifts are usually not stable enough for a precise calibration. Here a rather general method for effective suppression of the spurious effects caused by slow drifts in a large variety of instruments and experimental set-ups is described. An analytical derivation of an identity, describing the optimal measurement strategies suitable for suppressing the contribution of a slow drift described with a certain order polynomial function, is presented. A recursion rule as well as a general mathematical proof of the identity is given. The effectiveness of the discussed method is illustrated with an application of the derived optimal scanning strategies to precise surface slope measurements with a surface profiler.

  9. Suppression of Leidenfrost effect via low frequency vibrations

    NASA Astrophysics Data System (ADS)

    Ng, Boon Thiam; Hung, Yew Mun; Tan, Ming Kwang

    2015-11-01

    Leidenfrost effect occurs when vapor layer forms in between the coolant and the hot surface above Leidenfrost point, which dramatically reduces the cooling efficiency due to low thermal conductivity of the vapor layer. To prevent surface overheating, there have been number of reported methods to suppress the Leidenfrost effect that were mainly based on functionalization of the substrate surface and application of electric field across the droplet and substrate. In this work, we induce low frequency vibrations (f ~ 100 Hz) to the heated substrate to suppress the Leidenfrost effect. Three distinct impact dynamics are observed based on different magnitudes of surface acceleration and surface temperature. In gentle film boiling regime, formation of thin spreading lamella around the periphery of the impinged droplet is observed; in film boiling regime, due to thicker vapor cushion, rebound of the impinged droplet is observed; in contact boiling regime, due to the direct contact between the impinged droplet and heated substrate, ejection of the tiny droplet is observed. Also, estimated cooling enhancement ratio for contact boiling regime shows an improvement from 95% to 105%.

  10. An experimental evaluation of tic suppression and the tic rebound effect.

    PubMed

    Himle, Michael B; Woods, Douglas W

    2005-11-01

    Tourette's syndrome (TS) is a neurobiological disorder consisting of motor and vocal tics that are thought to be temporarily suppressible. Many professionals, however, believe that a paradoxical increase in tic frequency (above baseline levels) occurs when efforts to suppress have ceased (i.e., a rebound effect). To date, little research has investigated tic suppression or its effects. This study examined tic frequency during baseline, suppression, and post-suppression conditions using an experimental preparation reported to reliably produce tic suppression in children. Six children with TS and one with chronic tic disorder (CTD) were recorded during baseline and repeated suppression and post-suppression conditions. Tic frequency was significantly lower during suppression as compared to baseline. Although tic frequency during post-suppression was higher than during suppression, it was lower than baseline levels, arguing against a "rebound" effect of tic suppression. Exploratory analyses revealed that scores on the attention problems subscale of the Child Behavior Checklist significantly predicted tic suppressibility. The relationships between age, tic severity, and tic suppressibility were also explored. PMID:16159587

  11. Effect of gastric acid suppressants on human gastric motility

    PubMed Central

    Parkman, H; Urbain, J; Knight, L; Brown, K; Trate, D; Miller, M; Maurer, A; Fisher, R

    1998-01-01

    Background—The effect of histamine H2 receptor antagonists on gastric emptying is controversial. 
Aims—To determine the effects of ranitidine, famotidine, and omeprazole on gastric motility and emptying. 
Patients and methods—Fifteen normal subjects underwent simultaneous antroduodenal manometry, electrogastrography (EGG), and gastric emptying with dynamic antral scintigraphy (DAS). After 30 minutes of fasting manometry and EGG recording, subjects received either intravenous saline, ranitidine, or famotidine, followed by another 30 minutes recording and then three hours of postprandial recording after ingestion of a radiolabelled meal. Images were obtained every 10-15 minutes for three hours to measure gastric emptying and assess antral contractility. Similar testing was performed after omeprazole 20 mg daily for one week. 
Results—Fasting antral phase III migrating motor complexes (MMCs) were more common after ranitidine (9/15 subjects, 60%), famotidine (12/15, 80%), and omeprazole (8/12, 67%) compared with placebo (4/14, 29%; p<0.05). Postprandially, ranitidine, famotidine, and omeprazole slowed gastric emptying, increased the amplitude of DAS contractions, increased the EGG power, and increased the antral manometric motility index. 
Conclusions—Suppression of gastric acid secretion with therapeutic doses of gastric acid suppressants is associated with delayed gastric emptying but increased antral motility. 

 Keywords: gastric motility; gastric emptying; histamine H2 receptor antagonists; proton pump inhibitors; gastric acid secretion; scintigraphy PMID:9536950

  12. 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. PMID:26915998

  13. 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.

  14. Attempted suppression of social threat thoughts: differential effects for social phobia and healthy controls?

    PubMed

    Kingsep, Patrick; Page, Andrew

    2010-07-01

    Thought suppression research in the area of social phobia provides conflicting evidence regarding whether individuals demonstrate a general deficit or successful suppression. This paper reports the outcome of two studies using an online thought suppression paradigm measuring activation of target thoughts. Study 1 examined the effects of suppressing social threat stimuli with a healthy control group. Surprisingly, the results showed that participants demonstrated non-suppression of this stimuli class. Study 2 compared individuals with social phobia to a control group using the same stimuli as Study 1. Results revealed that following instructions to suppress social threat stimuli, individuals with social phobia demonstrated successful suppression, whilst the control group, as in Study 1, did not. The lack of suppression of social threat information by the control group may reflect functional impression-management of social threat stimuli. Whereas, successful suppression of these stimuli by individuals with social phobia, may contribute to diminished habituation to such information. PMID:20421097

  15. 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

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

    PubMed

    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

  17. Effects of residual stress on irradiation hardening in stainless steels

    NASA Astrophysics Data System (ADS)

    Okubo, N.; Miwa, Y.; Kondo, K.; Kaji, Y.

    2009-04-01

    Effects of residual stress on irradiation hardening were studied in advance for predicting irradiation assisted stress corrosion cracking. The specimens of SUS316 and SUS316L with several % plastic strains, which correspond to weld residual stress, were prepared by bending and keeping deformation under irradiation. Ion irradiations of 12 MeV Ni 3+ were performed at 330, 400 and 550 oC to 45 dpa. No bended specimen was simultaneously irradiated with the bended specimen. The residual stress was estimated by X-ray residual stress measurements before and after the irradiation. The micro-hardness was measured by using nanoindenter. The residual stress did not relax even for the case of the higher temperature aging at 500 oC for the same time of irradiation. The residual stress after ion irradiation up to high dpa, however, relaxed at these experimental temperatures. The irradiation hardening of stressed specimen was obviously lower than that of un-stressed one in case of SUS316L irradiated at 300 oC to 12 dpa.

  18. Effect of preoperative irradiation on healing of low colorectal anastomoses

    SciTech Connect

    Morgenstern, L.; Sanders, G.; Wahlstrom, E.; Yadegar, J.; Amodeo, P.

    1984-02-01

    The effect of preoperative irradiation on the healing of low colorectal anastomoses was studied experimentally. In 12 dogs in whom preoperative irradiation of 4,000 rads was given before low colorectal stapled anastomosis was performed, anastomotic leakage occurred in 66 percent. More than half of the anastomotic leaks were associated with either severe sepsis or death. In a matched group of control animals that underwent stapled anastomoses without irradiation, no anastomotic complications occurred. The clinical implications of this study are that stapled anastomoses in irradiated colon are at serious risk of anastomotic dehiscence and, therefore, should be protected with a proximal colostomy.

  19. 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.

  20. 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.

  1. IL-17 induces radiation resistance of B lymphoma cells by suppressing p53 expression and thereby inhibiting irradiation-triggered apoptosis

    PubMed Central

    Li, Qingshan; Xu, Xin; Zhong, Weijie; Du, Qinghua; Yu, Bizhen; Xiong, Huabao

    2015-01-01

    p53 is a well-known tumor suppressor. However, the regulatory mechanism(s) for p53 expression in B lymphoma cells, and the possible role of p53 in the development of the radioresistance in tumor cells are largely unknown. A human B lymphoma cell line, Karpas1106 (k1106), was used as a model of radioresistance. Apoptosis of k1106 cells was determined using flow cytometry. Expression of p53 was assessed using real time RT-PCR and western blotting. The results showed that irradiation at 8 Gy induced apoptosis in up to 40% of k1106 cells. At the same time, the irradiation markedly increased IL-6 production of the k1106 cells. When k1106 cells were cocultured with regulatory T cells (Tregs) and irradiated, the rate of apoptotic k1106 cells was significantly reduced, indicating an acquired resistance to irradiation. IL-6 derived from the irradiation-treated k1106 cells induced IL-17 expression in Tregs. The IL-17+Foxp3+ T cells suppressed p53 expression in k1106 cells. Collectively, irradiated k1106 cells induce the expression of IL-17 in Tregs, which interferes with the expression of p53 protein in k1106 cells and thereby represses irradiation-triggered apoptosis in k1106 cells. PMID:25544504

  2. 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

  3. 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.

  4. Effects of whole-body irradiation on neonatally thymectomized mice. Incidence of benign and malignant tumors.

    PubMed Central

    Anderson, R. E.; Howarth, J. L.; Troup, G. M.

    1978-01-01

    The individual and combined effects of neonatal thymectomy and whole-body irradiation on the prevalence of benign and malignant tumors in germ-free female mice of the Charles Rivers line were studied to determine if a portion of the tumorigenic effects of irradiation can be attributed to injury of the thymic-dependent component of the immune response. Neonatal thymectomy increased a) the incidence of benign and malignant tumors and b) the prevalence of multiple primary neoplasms in an individual mouse. Whole-body exposure to 700 rad at 6 weeks of age further increased th incidence of tumors, but the relative magnitude of this increase was less pronounced than in sham-operated controls. Thus, the cumulative effects of thymectomy plus irradiation are less pronounced than the sum of the individual effects. One of several possible explanations for this observation is that a portion of the carcinogenic effects of whole-body irradiation is mediated by suppression of the thymic-dependent component of the immune response. PMID:645825

  5. 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).

  6. Effect of neutron irradiation on vanadium alloys

    SciTech Connect

    Braski, D.N.

    1986-01-01

    Neutron-irradiated vanadium alloys were evaluated for their susceptibility to irradiation hardening, helium embrittlement, swelling, and residual radioactivity, and the results were compared with those for the austenitic and ferritic stainless steels. The VANSTAR-7 and V-15Cr-5Ti alloys showed the greatest hardening between 400 and 600/sup 0/C while V-3Ti-1Si and V-20Ti had lower values that were comparable to those of ferritic steels. The V-15Cr-5Ti and VANSTAR-7 alloys were susceptible to helium embrittlement caused by the combination of weakened grain boundaries and irradiation-hardened grain matrices. Specimen fractures were entirely intergranular in the most severe instances of embrittlement. The V-3Ti-1Si and V-20Ti alloys were more resistant to helium embrittlement. Except for VANSTAR-7 irradiated to 40 dpa at 520/sup 0/C, all of the vanadium alloys exhibited low swelling that was similar to the ferritic steels. Swelling was greater in specimens that were preimplanted with helium using the tritium trick. The vanadium alloys clearly exhibit lower residual radioactivity after irradiation than the ferrous alloys.

  7. [Meta-cognitive beliefs about thought suppression and associated paradoxical effects].

    PubMed

    Hattori, Yosuke; Honma, Yoshiko; Tanno, Yoshihiko

    2014-10-01

    The purpose of this study was to clarify the contents of meta-cognitive beliefs about thought suppression and to investigate the relationship between these beliefs and the paradoxical effects of thought suppression. In Study 1, we developed a scale measuring the endorsement of meta-cognitive beliefs about thought suppression. This measure, the Meta-cognitive Beliefs about Thought Suppression Questionnaire (BTQ, has four subscales: Distraction, Paradoxical Effect, Regret, and Promotion of Concentration. In Study 2 and Study 3, the BTQ showed sufficient criterion-related validity and test-retest reliability. In Study 4, we conducted an experiment to investigate the relationship between meta-cognitive beliefs about thought suppression and its paradoxical eftects. Results showed that the Paradoxical Effect subscale score significantly predicted the number of intrusive thoughts during thought suppression. The development process of meta-cognitive beliefs about thought suppression and implications for research about cognitive control are discussed. PMID:25486842

  8. [Meta-cognitive beliefs about thought suppression and associated paradoxical effects].

    PubMed

    Hattori, Yosuke; Honma, Yoshiko; Tanno, Yoshihiko

    2014-10-01

    The purpose of this study was to clarify the contents of meta-cognitive beliefs about thought suppression and to investigate the relationship between these beliefs and the paradoxical effects of thought suppression. In Study 1, we developed a scale measuring the endorsement of meta-cognitive beliefs about thought suppression. This measure, the Meta-cognitive Beliefs about Thought Suppression Questionnaire (BTQ, has four subscales: Distraction, Paradoxical Effect, Regret, and Promotion of Concentration. In Study 2 and Study 3, the BTQ showed sufficient criterion-related validity and test-retest reliability. In Study 4, we conducted an experiment to investigate the relationship between meta-cognitive beliefs about thought suppression and its paradoxical eftects. Results showed that the Paradoxical Effect subscale score significantly predicted the number of intrusive thoughts during thought suppression. The development process of meta-cognitive beliefs about thought suppression and implications for research about cognitive control are discussed. PMID:25508973

  9. Effects of UV-B irradiation on a marine microecosystem.

    PubMed

    Marangoni, Roberto; Messina, Nicola; Gioffré, Domenico; Colombetti, Giuliano

    2004-01-01

    Purpose of this work was to study the effect of UV irradiation on a microecosystem consisting of several interacting species. The system chosen was of a hypersaline type, where all the species present live at high salt concentration; it comprises different bacteria; a producer, the photosynthetic green alga Dunaliella salina; and a consumer, the ciliated protozoan Fabrea salina, which form a complete food chain. We were able to establish the initial conditions that give rise to a self-sustaining microecosystem, stable for at least 3 weeks. We then determined the effect of UV irradiation on this microecosystem under laboratory-controlled conditions, in particular by measuring the critical UV exposure for the two main components of the microecosystem (algae and protozoa) under UV-B irradiances comparable to those of solar irradiation. In our experiments, we varied irradiance, total dose and spectral composition of the actinic light. The critical doses at irradiances of the order of 56 kJ/m(2) (typical average daily irradiance in a sunny summer day in Pisa), measured for each main component of the microecosystem (algae and ciliates), turned out to be around 70 kJ/m(2) for ciliates and 50 kJ/m(2) for D. salina. By exposing microecosystems to daily UV-B irradiances of the order of 8 kJ/m(2) (typical average daily irradiance in a sunny winter day in Pisa), we found no effect at total doses of the order of the critical doses at high irradiances, showing that the reciprocity law does not hold. We have also measured a preliminary spectral-sensitive curve of the UV effects, which shows an exponential decay with wavelength. PMID:15339218

  10. Neutron irradiation effects in GaAs

    SciTech Connect

    Patel, J.U.

    1992-01-01

    Changes in electrical properties of n-GaAs as a result of irradiations with fast neutron have been studied, after epitaxial layers doped with Si at concentrations in the range 1.35 x 10[sup 15] to 1.60 x 10[sup 16] cm[sup [minus]3] were irradiated with reactor neutron fluences up to 1.31 x 10[sup 15] cm [sup [minus]2]. When the changes in carrier concentration, Hall mobility and resistivity were more than 25% of their initial values, nonlinear dependence on neutron fluence was apparent. New theory is proposed which explains the changes in electrical properties in terms of rates of trapping and release of charges. A theoretical relationship is derived for the change in carrier concentration as a function of neutron fluence and Fermi level shift was found to be consistent with the observed changes in carrier concentration. A correlation has been found between the changes in carrier concentration and mobility with neutron fluence using newly defined physically meaningful parameters in the case of two pairs of samples. The correlation has been explained in terms of the increased scattering of charge carriers from the defects created by neutrons that trap the free carriers. Mobility changes were measured at temperatures from 15 K to 305 K in n-GaAs van-der Pauw samples irradiated by fast reactor neutrons. The inverse mobility values obtain versus temperature, from the variable temperature Hall measurements, in the case of irradiated and in-irradiated samples were fitted using the relation [mu][sup [minus]1] = T[sup [minus]3/2] + B T[sup 3/2]. The inverse mobility increased as a result of neutron irradiations over the whole range of temperature, the increase being attributed to the increased scattering from neutron induced charged defects.

  11. 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.

  12. Modeling injected interstitial effects on void swelling in self-ion irradiation experiments

    NASA Astrophysics Data System (ADS)

    Short, M. P.; Gaston, D. R.; Jin, M.; Shao, L.; Garner, F. A.

    2016-04-01

    Heavy ion irradiations at high dose rates are often used to simulate slow and expensive neutron irradiation experiments. However, many differences in the resultant modes of damage arise due to unique aspects of heavy ion irradiation. One such difference was recently shown in pure iron to manifest itself as a double peak in void swelling, with both peaks located away from the region of highest displacement damage. In other cases involving a variety of ferritic alloys there is often only a single peak in swelling vs. depth that is located very near the ion-incident surface. We show that these behaviors arise due to a combination of two separate effects: 1) suppression of void swelling due to injected interstitials, and 2) preferential sinking of interstitials to the ion-incident surface, which are very sensitive to the irradiation temperature and displacement rate. Care should therefore be used in collection and interpretation of data from the depth range outside the Bragg peak of ion irradiation experiments, as it is shown to be more complex than previously envisioned.

  13. gamma-Irradiation of PEGd,lPLA and PEG-PLGA multiblock copolymers. I. Effect of irradiation doses.

    PubMed

    Dorati, R; Colonna, C; Serra, M; Genta, I; Modena, T; Pavanetto, F; Perugini, P; Conti, B

    2008-01-01

    To evaluate the effects of different gamma irradiation doses on PEGd,lPLA and PEG-PLGA multiblock copolymers. The behaviour of the multiblock copolymers to irradiation was compared to that of PLA, PLGA polymers. PEGd,lPLA, PEG-PLGA, PLA and PLGA polymers were irradiated by using a (60)Co irradiation source at 5, 15, 25 and 50 kGy total dose. Characterization was performed on all samples before and after irradiation, by nuclear magnetic resonance (NMR), infrared absorption spectrophotometry (FTIR) and gel permeation chromatography (GPC). The effect of gamma irradiation on polymer stability was also evaluated. Results of NMR and FTIR suggest an increase in -OH and -COOH groups, attributed to scission reactions induced by irradiation treatment. Data of GPC analysis showed that the weight average molecular weight (Mw) of polymer samples decreased with increasing irradiation dose. The extent of Mw degradation expressed as percentage of Mw reduction was more prominent for polymers with high molecular weight as PEGd,lPLA and PLA. The dominant effect of gamma-irradiation on both polymer samples was chain scission. The multiblock copolymer PEGd,lPLA presented higher sensitivity to irradiation treatment with respect to PLA, likely due to the presence of PEG in the matrix. The effect of gamma irradiation continues over a much longer period of time after gamma irradiation has been performed. It is suggested that the material reacts with oxygen to form peroxyl free radicals, which may further undergo degradation reactions during storage after irradiation. PMID:18528761

  14. Suppression of Adult Neurogenesis Increases the Acute Effects of Kainic Acid

    PubMed Central

    Iyengar, Sloka S.; LaFrancois, John J.; Friedman, Daniel; Drew, Liam J.; Denny, Christine A.; Burghardt, Nesha S.; Wu, Melody V.; Hsieh, Jenny; Hen, René; Scharfman, Helen E.

    2016-01-01

    Adult neurogenesis, the generation of new neurons in the adult brain, occurs in the hippocampal dentate gyrus (DG) and the olfactory bulb (OB) of all mammals, but the functions of these new neurons are not entirely clear. Originally, adult-born neurons were considered to have excitatory effects on the DG network, but recent studies suggest a net inhibitory effect. Therefore, we hypothesized that selective removal of newborn neurons would lead to increased susceptibility to the effects of a convulsant. This hypothesis was tested by evaluating the response to the chemoconvulsant kainic acid (KA) in mice with reduced adult neurogenesis, produced either by focal X-irradiation of the DG, or by pharmacogenetic deletion of dividing radial glial precursors. In the first 4 hrs after KA administration, when mice have the most robust seizures, mice with reduced adult neurogenesis had more severe convulsive seizures, exhibited either as a decreased latency to the first convulsive seizure, greater number of convulsive seizures, or longer convulsive seizures. Nonconvulsive seizures did not appear to change or they decreased. Four-21 hrs after KA injection, mice with reduced adult neurogenesis showed more interictal spikes (IIS) and delayed seizures than controls. Effects were greater when the anticonvulsant ethosuximide was injected 30 min prior to KA administration; ethosuximide allows forebrain seizure activity to be more easily examined in mice by suppressing seizures dominated by the brainstem. These data support the hypothesis that reduction of adult-born neurons increases the susceptibility of the brain to effects of KA. PMID:25476494

  15. Magnetic penetration-depth measurements of a suppressed superfluid density of superconducting Ca0.5Na0.5Fe2As2 single crystals by proton irradiation

    NASA Astrophysics Data System (ADS)

    Kim, Jeehoon; Haberkorn, N.; Graf, M. J.; Usov, I.; Ronning, F.; Civale, L.; Nazaretski, E.; Chen, G. F.; Yu, W.; Thompson, J. D.; Movshovich, R.

    2012-10-01

    We report on the dramatic effect of random point defects, produced by proton irradiation, on the superfluid density ρs in superconducting Ca0.5Na0.5Fe2As2 single crystals. The magnitude of the suppression is inferred from measurements of the temperature-dependent magnetic penetration depth λ(T) using magnetic force microscopy. Our findings indicate that a radiation dose of 2×1016 cm-2 produced by 3 MeV protons results in a reduction of the superconducting critical temperature Tc by approximately 10%. In contrast, ρs(0) is suppressed by approximately 60%. This breakdown of the Abrikosov-Gorkov theory may be explained by the so-called “Swiss cheese model,” which accounts for the spatial suppression of the order parameter near point defects similar to holes in Swiss cheese. Both the slope of the upper critical field and the penetration depth λ(T/Tc)/λ(0) exhibit similar temperature dependences before and after irradiation. This may be due to a combination of the highly disordered nature of Ca0.5Na0.5Fe2As2 with large intraband and simultaneous interband scattering as well as the s±-wave nature of short coherence length superconductivity.

  16. Effects of temperature during the irradiation of calcium carbonate.

    PubMed

    Negrón-Mendoza, Alicia; Camargo-Raya, Claudia; Gómez-Vidales, Virginia; Uribe, Roberto M; Ramos-Bernal, Sergio

    2016-05-01

    Calcium carbonate received gamma irradiation at different doses (0-309kGy) and temperature regimes (77-298K) to study the effects of irradiation temperature. The changes were followed by EPR spectroscopy. We observed the formation of a composite EPR spectrum, even at low radiation doses and temperature. There was a strong effect on the evaluation of the radicals formed as a function of irradiation temperature, probably due to the diffusion in the frozen powder and the recombination of some radicals at room temperature. PMID:26901240

  17. 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.

  18. Effect of green laser irradiation on hydrogen production

    NASA Astrophysics Data System (ADS)

    Bidin, Noriah; Razak, Siti Noraiza A.; Radiana Azni, Siti; Nguroho, Waskito; Mohsin, Ali Kamel; Abdullah, Mundzir; Krishnan, Ganesan; Bakhtiar, Hazri

    2014-06-01

    The effect of green laser irradiation on hydrogen production via water electrolysis was investigated. Diode pumped solid-state laser operating in second harmonic generation was employed as a source of irradiation. The hydrogen production system was also irradiated by a conventional light, a halogen source, for comparison. The best catalyst was identified by mixing distilled water with two types of salt: NaCl and Na2SO4. Optimization of hydrogen production from water electrolysis was realized by using NaCl and green laser irradiation. The power of green laser irradiation and the concentration of NaCl in water contribute to hydrogen production. The hydrogen yield also depends on the distance and direction of the green beam to the electrode.

  19. 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.

  20. Effects of chlorhexidine and fluoride on irradiated enamel and dentin.

    PubMed

    Soares, C J; Neiva, N A; Soares, P B F; Dechichi, P; Novais, V R; Naves, L Z; Marques, M R

    2011-05-01

    The effectiveness of mouthwash protocols in preventing gamma irradiation therapy damage to the ultimate tensile strength (UTS) of enamel and dentin is unknown. It was hypothesized that the use of chlorhexidine and fluoride mouthwash would maintain the UTS of dental structures. One hundred and twenty teeth were divided into 2 groups: irradiated (subjected to 60 Gy of gamma irradiation in daily increments of 2 Gy) and non-irradiated. They were then subdivided into 2 mouthwash protocols used 3 times per day: 0.12% chlorhexidine, 0.05% sodium fluoride, and control group (n = 10). The specimens were evaluated by microtensile testing. The results of the Tukey test (p < 0.05) indicated that the gamma irradiation therapy significantly reduced the UTS of the enamel, crown, and root dentin. Macromolecular alterations were suggested by optical retardation data in dentin. Structural alterations, in both substrates, were detected by scanning electron microscopy analysis. Mouthwash with 0.12% chlorhexidine partially prevented the damage to the mechanical properties of the irradiated crown dentin, whereas the 0.05% sodium-fluoride-irradiated enamel showed UTS similar to that of non-irradiated enamel. PMID:21335538

  1. Cost-effective suppression and eradication of invasive predators.

    PubMed

    Baxter, Peter W J; Sabo, John L; Wilcox, Chris; McCarthy, Michael A; Possingham, Hugh P

    2008-02-01

    predators can have pronounced effects on naïve prey species; thus, predator control is often essential for conservation of threatened native species. Complete eradication of the predator, although desirable, may be elusive in budget-limited situations, whereas predator suppression is more feasible and may still achieve conservation goals. We used a stochastic predator-prey model based on a Lotka-Volterra system to investigate the cost-effectiveness of predator control to achieve prey conservation. We compared five control strategies: immediate eradication, removal of a constant number of predators (fixed-number control), removal of a constant proportion of predators (fixed-rate control), removal of predators that exceed a predetermined threshold (upper-trigger harvest), and removal of predators whenever their population falls below a lower predetermined threshold (lower-trigger harvest). We looked at the performance of these strategies when managers could always remove the full number of predators targeted by each strategy, subject to budget availability. Under this assumption immediate eradication reduced the threat to the prey population the most. We then examined the effect of reduced management success in meeting removal targets, assuming removal is more difficult at low predator densities. In this case there was a pronounced reduction in performance of the immediate eradication, fixed-number, and lower-trigger strategies. Although immediate eradication still yielded the highest expected minimum prey population size, upper-trigger harvest yielded the lowest probability of prey extinction and the greatest return on investment (as measured by improvement in expected minimum population size per amount spent). Upper-trigger harvest was relatively successful because it operated when predator density was highest, which is when predator removal targets can be more easily met and the effect of predators on the prey is most damaging. This suggests that controlling

  2. Effect of nitrogen-containing substituents on fragmentation of perylene derivatives under laser irradiation

    NASA Astrophysics Data System (ADS)

    Komolov, A. S.; Komolov, S. A.; Lazneva, E. F.; Turiev, A. M.

    2012-01-01

    The effect of nitrogen-containing substituents such as phenyl imide and actyl imide on the character of fragmentation of perylene derivative molecules under laser irradiation has been studied by laser desorption (LD) mass spectrometry. Replacement of the central oxygen atom by a nitrogen atom in anhydride carboxy groups in perylene tetracarboxylic dianhydride (PTCDA) molecule results in the suppression of CO2 desorption and predominant desorption of CO. The LD mass spectrum exhibits peaks that correspond to fragments of the perylene nucleus and those of the aromatic and aliphatic substituents. Intact PTCDA molecules are present in the desorbed flux in insignificant amounts.

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

    USGS Publications Warehouse

    Millard, H.T., Jr.

    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.

  4. 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

  5. BlueBerry Isolate, Pterostilbene, Functions as a Potential Anticancer Stem Cell Agent in Suppressing Irradiation-Mediated Enrichment of Hepatoma Stem Cells

    PubMed Central

    Lee, Chi-Ming; Su, Yen-Hao; Huynh, Thanh-Tuan; Lee, Wei-Hwa; Chiou, Jeng-Fong; Lin, Yen-Kuang; Hsiao, Michael; Wu, Chih-Hsiung; Lin, Yuh-Feng; Wu, Alexander T. H.; Yeh, Chi-Tai

    2013-01-01

    For many malignancies, radiation therapy remains the second option only to surgery in terms of its curative potential. However, radiation-induced tumor cell death is limited by a number of factors, including the adverse response of the tumor microenvironment to the treatment and either intrinsic or acquired mechanisms of evasive resistance, and the existence of cancer stem cells (CSCs). In this study, we demonstrated that using different doses of irradiation led to the enrichment of CD133+ Mahlavu cells using flow cytometric method. Subsequently, CD133+ Mahlavu cells enriched by irradiation were characterized for their stemness gene expression, self-renewal, migration/invasion abilities, and radiation resistance. Having established irradiation-enriched CD133+ Mahlavu cells with CSC properties, we evaluated a phytochemical, pterostilbene (PT), found abundantly in blueberries, against irradiation-enriched CSCs. It was shown that PT treatment dose-dependently reduced the enrichment of CD133+ Mahlavu cells upon irradiation; PT treatment also prevented tumor sphere formation, reduced stemness gene expression, and suppressed invasion and migration abilities as well as increasing apoptosis of CD133+ Mahlavu CSCs. Based on our experimental data, pterostilbene could be used to prevent the enrichment of CD133+ hepatoma CSCs and should be considered for future clinical testing as a combined agent for HCC patients. PMID:23878592

  6. Effects of gamma irradiation on solid and lyophilised phospholipids

    NASA Astrophysics Data System (ADS)

    Stensrud, G.; Redford, K.; Smistad, G.; Karlsen, J.

    1999-11-01

    The effects of gamma irradiation (25 kGy) as a sterilisation method for phospholipids (distearoylphosphatidylcholine and distearoylphosphatidylglycerol) were investigated. 31P-NMR revealed minor chemical degradation of the phospholipids but lower dynamic viscosity and pseudoplasticity, lower turbidity, higher diffusion constant, smaller size, more negative zeta potential and changes in the phase transition behaviour of the subsequently produced liposomes were observed. The observed changes could to some extent be explained by the irradiation-induced degradation products (distearoylphosphatidic acid, fatty acids, lysophospholipids).

  7. 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.

  8. Effects of Electron Beam Irradiation on the Electrospinning of Polyacrylonitrile.

    PubMed

    Jeun, Joon-Pyo; Kim, Hyun-Bin; Oh, Seung-Hwan; Park, Jung-Ki; Kang, Phil-Hyun

    2015-08-01

    Electron beam (e-beam) irradiation of polyacrylonitrile (PAN) was performed to investigate the effects of radiation on the electrospinning process. For this study, polyacrylonitrile powder was subjected to e-beam irradiation with different doses of up to 100 kGy under an N2 atmosphere. Polymer solutions were prepared by dissolving PAN in N,N-dimethyl-formamide (DMF) at a 1:9 ratio by weight. The prepared PAN/DMF solutions showed different colors with different e-beam doses. The resulting structures in solutions contained conjugated C=N bonds, which caused the observed color formation. In addition, the conductivity of the PAN/DMF solution increased with an increase in e-beam irradiation dose. In the DSC spectra of electrospun PAN fibers, the peak temperature of the exothermic reactions was observed to decrease with an increase in the e-beam irradiation strength. PMID:26369176

  9. Suppression of particle dispersion by sweeping effects in synthetic turbulence.

    PubMed

    Eyink, Gregory L; Benveniste, Damien

    2013-02-01

    Synthetic models of Eulerian turbulence like so-called kinematic simulations (KS) are often used as computational shortcuts for studying Lagrangian properties of turbulence. These models have been criticized by Thomson and Devenish (2005), who argued on physical grounds that sweeping decorrelation effects suppress pair dispersion in such models. We derive analytical results for Eulerian turbulence modeled by Gaussian random fields, in particular for the case with zero mean velocity. Our starting point is an exact integrodifferential equation for the particle pair separation distribution obtained from the Gaussian integration-by-parts identity. When memory times of particle locations are short, a Markovian approximation leads to a Richardson-type diffusion model. We obtain a time-dependent pair diffusivity tensor of the form K(ij)(r,t)=S(ij)(r)τ(r,t), where S(ij)(r) is the structure-function tensor and τ(r,t) is an effective correlation time of velocity increments. Crucially, this is found to be the minimum value of three times: the intrinsic turnover time τ(eddy)(r) at separation r, the overall evolution time t, and the sweeping time r/v(0) with v(0) the rms velocity. We study the diffusion model numerically by a Monte Carlo method. With inertial ranges like the largest achieved in most current KS (about 6 decades long), our model is found to reproduce the t(9/2) power law for pair dispersion predicted by Thomson and Devenish and observed in the KS. However, for much longer ranges, our model exhibits three distinct pair-dispersion laws in the inertial range: a Batchelor t(2) regime, followed by a Kraichnan-model-like t(1) diffusive regime, and then a t(6) regime. Finally, outside the inertial range, there is another t(1) regime with particles undergoing independent Taylor diffusion. These scalings are exactly the same as those predicted by Thomson and Devenish for KS with large mean velocities, which we argue hold also for KS with zero mean velocity. Our results

  10. Suppression of particle dispersion by sweeping effects in synthetic turbulence

    NASA Astrophysics Data System (ADS)

    Eyink, Gregory L.; Benveniste, Damien

    2013-02-01

    Synthetic models of Eulerian turbulence like so-called kinematic simulations (KS) are often used as computational shortcuts for studying Lagrangian properties of turbulence. These models have been criticized by Thomson and Devenish (2005), who argued on physical grounds that sweeping decorrelation effects suppress pair dispersion in such models. We derive analytical results for Eulerian turbulence modeled by Gaussian random fields, in particular for the case with zero mean velocity. Our starting point is an exact integrodifferential equation for the particle pair separation distribution obtained from the Gaussian integration-by-parts identity. When memory times of particle locations are short, a Markovian approximation leads to a Richardson-type diffusion model. We obtain a time-dependent pair diffusivity tensor of the form Kij(r,t)=Sij(r)τ(r,t), where Sij(r) is the structure-function tensor and τ(r,t) is an effective correlation time of velocity increments. Crucially, this is found to be the minimum value of three times: the intrinsic turnover time τeddy(r) at separation r, the overall evolution time t, and the sweeping time r/v0 with v0 the rms velocity. We study the diffusion model numerically by a Monte Carlo method. With inertial ranges like the largest achieved in most current KS (about 6 decades long), our model is found to reproduce the t9/2 power law for pair dispersion predicted by Thomson and Devenish and observed in the KS. However, for much longer ranges, our model exhibits three distinct pair-dispersion laws in the inertial range: a Batchelor t2 regime, followed by a Kraichnan-model-like t1 diffusive regime, and then a t6 regime. Finally, outside the inertial range, there is another t1 regime with particles undergoing independent Taylor diffusion. These scalings are exactly the same as those predicted by Thomson and Devenish for KS with large mean velocities, which we argue hold also for KS with zero mean velocity. Our results support the basic

  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. High Temperature Irradiation Effects in Selected Generation IV Structural Alloys

    SciTech Connect

    Nanstad, Randy K; McClintock, David A; Hoelzer, David T; Tan, Lizhen; Allen, Todd R.

    2009-01-01

    In the Generation IV Materials Program cross-cutting task, irradiation and testing were carried out to address the issue of high temperature irradiation effects with selected current and potential candidate metallic alloys. The materials tested were (1) a high-nickel iron-base alloy (Alloy 800H); (2) a nickel-base alloy (Alloy 617); (3) two advanced nano-structured ferritic alloys (designated 14YWT and 14WT); and (4) a commercial ferritic-martensitic steel (annealed 9Cr-1MoV). Small tensile specimens were irradiated in rabbit capsules in the High-Flux Isotope Reactor at temperatures from about 550 to 700 C and to irradiation doses in the range 1.2 to 1.6 dpa. The Alloy 800H and Alloy 617 exhibited significant hardening after irradiation at 580 C; some hardening occurred at 660 C as well, but the 800H showed extremely low tensile elongations when tested at 700 C. Notably, the grain boundary engineered 800H exhibited even greater hardening at 580 C and retained a high amount of ductility. Irradiation effects on the two nano-structured ferritic alloys and the annealed 9Cr-1MoV were relatively slight at this low dose.

  13. 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.

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

    DOE PAGESBeta

    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 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

  15. Immunosuppression in irradiated breast cancer patients: In vitro effect of cyclooxygenase inhibitors

    SciTech Connect

    Wasserman, J.; Blomgren, H.; Rotstein, S.; Petrini, B.; Hammarstroem, S.

    1989-01-01

    We have documented in previous studies that local irradiation therapy for breast cancer caused severe lymphopenia with reduction of both T and non-T lymphocytes. Non-T cells were relatively more depressed but recovered within six months. The recovery of T cells, on the other hand, remained incomplete 10-11 years after irradiation. Several lymphocyte functions were also severely impaired. An association was found between prognosis and postirradiation mitogen reactivity of lymphocytes from these patients. Mortality up to eight years after irradiation was significantly higher in patients with low postirradiation phytohemagglutinin and PPD reactivity. The radiation induced decrease in mitogenic response seemed mainly to be caused by immunosuppressive monocytes, which suggests that the underlying mechanism might be mediated by increased production of prostaglandins by monocytes. For this reason we examined the effect of some cyclooxygenase products on different lymphocyte functions and found that prostaglandins A2, D2, and E2 inhibited phytohemagglutinin response in vitro. Natural killer cell activity was also reduced by prostaglandins D2 and E2. The next step was to examine various inhibitors of cyclooxygenase in respect to their capacity to revert irradiation-induced suppression of in vitro mitogen response in lymphocytes from breast cancer patients. It was demonstrated that Diclofenac Na (Voltaren), Meclofenamic acid, Indomethacin, and lysin-mono-acetylsalicylate (Aspisol) could enhance mitogen responses both before and after radiation therapy. This effect was most pronounced at completion of irradiation. On a molar basis, Diclofenac Na was most effective followed by Indomethacin, Meclofenamic acid, and lysin-monoacetylsalicylate.

  16. 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...

  17. 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,…

  18. Opioid peptides mediate the suppressive effect of stress on natural killer cell cytotoxicity.

    PubMed

    Shavit, Y; Lewis, J W; Terman, G W; Gale, R P; Liebeskind, J C

    1984-01-13

    The cytotoxic activity of natural killer cells was investigated in rats subjected to one of two inescapable footshock stress paradigms, both of which induce analgesia, but only one via activation of opioid mechanisms. Splenic natural killer cell activity was suppressed by the opioid, but not the nonopioid, form of stress. This suppression was blocked by the opioid antagonist naltrexone. Similar suppression of natural killer activity was induced by high doses of morphine. These results suggest that endogenous opioid peptides mediate the suppressive effect of certain forms of stress on natural killer cell cytotoxicity. PMID:6691146

  19. Effects of gamma-irradiation on biosynthesis of different types of ribonucleic acids in normal and regenerating rat liver.

    PubMed Central

    Markov, G G; Dessev, G N; Russev, G C; Tsanev, R G

    1975-01-01

    1. The effect of gamma-irradiation (4000rd) on the synthesis of ribosomal (pre-rRNA) and heterogeneous nuclear RNA (pre-mRNA) in normal and in regenerating rat liver was studied by using 40 min labelling with [6(-14)C]orotic acid. 2. Partial hepatectomy caused a sharp transient increase in the specific radioactivity of the endogenous low-molecular-weight RNA precursors in the livers of both normal and irradiated rats. Irradiation of intact animals did not affect the pool. 3. Irradiation enhanced the synthesis of pre-rRNA for at least 12h. The synthesis of pre-mRNA was also enhanced, but only in the first 3h after irradiation. 4. Partial hepatectomy strongly stimulated the synthesis of both pre-rRNA and pre-mRNA. 5. The synthesis of pre-rRNA was enhanced also in regenerating liver of animals irradiated before or after the operation. The conclusion can be drawn that the early increase in the synthesis of ribosomal RNA is a non-specific cellular response to different injuring factors. 6. The only case where irradiation caused an early inhibition of RNA synthesis was that of pre-mRNA in regenerating liver. This supports the hypothesis that ionizing radiation does not suppress the transcription per se but affects the mechanisms of activation of new genes (cellular programming). PMID:1147904

  20. EVALUATION OF THE EFFECTIVENESS OF CHEMICAL DUST SUPPRESSANTS ON UNPAVED ROADS

    EPA Science Inventory

    The report gives results of measurements of the long-term effectiveness of five unpaved-road chemical dust suppressants. Effectiveness at controlling total particulate emissions in three size fractions was determined over several cycles of chemical application, control effectiven...

  1. 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…

  2. 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.

  3. Effect of gamma ray irradiation on sodium borate single crystals

    NASA Astrophysics Data System (ADS)

    Kalidasan, M.; Asokan, K.; Baskar, K.; Dhanasekaran, R.

    2015-12-01

    In this work, the effects of 5 kGy, 10 kGy and 20 kGy doses of gamma ray irradiation on sodium borate, Na2[B4O5(OH)4]·(H2O)8 single crystals have been studied. Initially these crystals were grown by solution growth technique and identified as monoclinic using X-ray diffraction analysis. X-ray rocking curves confirm the formation of crystalline defects due to gamma rays in sodium borate single crystals. The electron paramagnetic resonance spectra have been recorded to identify the radicals created due to gamma ray irradiation in sodium borate single crystals. The thermoluminescence glow curves due to the defects created by gamma rays in this crystal have been observed and their kinetic parameters were calculated using Chen's peak shape method. The optical absorption increases and photoluminescence spectral intensity decreases for 5 kGy and 20 kGy doses gamma ray irradiated crystals compared to pristine and 10 kGy dose irradiated one. The effect of various doses of gamma rays on vibrational modes of the sodium borate single crystals was studied using FT-Raman and ATR-FTIR spectral analysis. The dielectric permittivity, conductance and dielectric loss versus frequency graphs of these crystals have been analyzed to know the effect of gamma ray irradiation on these parameters.

  4. Rescue effects: irradiated cells helped by unirradiated bystander cells.

    PubMed

    Lam, R K K; Fung, Y K; Han, W; Yu, K N

    2015-01-01

    The rescue effect describes the phenomenon where irradiated cells or organisms derive benefits from the feedback signals sent from the bystander unirradiated cells or organisms. An example of the benefit is the mitigation of radiation-induced DNA damages in the irradiated cells. The rescue effect can compromise the efficacy of radioimmunotherapy (RIT) (and actually all radiotherapy). In this paper, the discovery and subsequent confirmation studies on the rescue effect were reviewed. The mechanisms and the chemical messengers responsible for the rescue effect studied to date were summarized. The rescue effect between irradiated and bystander unirradiated zebrafish embryos in vivo sharing the same medium was also described. In the discussion section, the mechanism proposed for the rescue effect involving activation of the nuclear factor κB (NF-κB) pathway was scrutinized. This mechanism could explain the promotion of cellular survival and correct repair of DNA damage, dependence on cyclic adenosine monophosphate (cAMP) and modulation of intracellular reactive oxygen species (ROS) level in irradiated cells. Exploitation of the NF-κB pathway to improve the effectiveness of RIT was proposed. Finally, the possibility of using zebrafish embryos as the model to study the efficacy of RIT in treating solid tumors was also discussed. PMID:25625514

  5. Rescue Effects: Irradiated Cells Helped by Unirradiated Bystander Cells

    PubMed Central

    Lam, R. K. K.; Fung, Y. K.; Han, W.; Yu, K. N.

    2015-01-01

    The rescue effect describes the phenomenon where irradiated cells or organisms derive benefits from the feedback signals sent from the bystander unirradiated cells or organisms. An example of the benefit is the mitigation of radiation-induced DNA damages in the irradiated cells. The rescue effect can compromise the efficacy of radioimmunotherapy (RIT) (and actually all radiotherapy). In this paper, the discovery and subsequent confirmation studies on the rescue effect were reviewed. The mechanisms and the chemical messengers responsible for the rescue effect studied to date were summarized. The rescue effect between irradiated and bystander unirradiated zebrafish embryos in vivo sharing the same medium was also described. In the discussion section, the mechanism proposed for the rescue effect involving activation of the nuclear factor κB (NF-κB) pathway was scrutinized. This mechanism could explain the promotion of cellular survival and correct repair of DNA damage, dependence on cyclic adenosine monophosphate (cAMP) and modulation of intracellular reactive oxygen species (ROS) level in irradiated cells. Exploitation of the NF-κB pathway to improve the effectiveness of RIT was proposed. Finally, the possibility of using zebrafish embryos as the model to study the efficacy of RIT in treating solid tumors was also discussed. PMID:25625514

  6. X-ray versus gamma irradiation effects on polymers

    NASA Astrophysics Data System (ADS)

    Croonenborghs, B.; Smith, M. A.; Strain, P.

    2007-11-01

    Today, the most common methods used for medical device sterilisation are by gaseous ethylene oxide and by electron beam or gamma irradiation. With X-ray sterilisation about to enter the market, its material compatibility needs to be assessed at doses typically encountered during a sterilisation process. This paper reports on a study that compares the effects of exposing different types of plastics that are commonly used in medical devices to 60Co or to 5 MeV X-rays. The dose rate for both irradiation modalities was of the same order of magnitude. Under these conditions, both types of radiation are found to have similar effects on polymer properties.

  7. Effect of gamma irradiation on rice and its food products

    NASA Astrophysics Data System (ADS)

    Sung, Wen-Chieh

    2005-07-01

    Two milled indica rice varieties were exposed to gamma radiation with doses ranging from 0 to 1.0 kGy. The effects of gamma irradiation on rice flour pasting properties and the qualities of its food product, rice curd, were compared to the effects of storage. A dose of 1 kGy can decrease the flour paste viscosity and tenderize the texture of the rice curd to similar levels as those obtained after 12 months of storage. It was thus shown that gamma irradiation could shorten the indica rice aging time and improve the processing stability and quality of rice products.

  8. Effects of aeration on gamma irradiation of sewage sludge

    NASA Astrophysics Data System (ADS)

    Chu, Libing; Wang, Jianlong; Wang, Bo

    2010-08-01

    In this paper the effect of aeration on gamma irradiation of sewage sludge was investigated to examine the potential solubilization of solids in sewage sludge to ultimately reduce the solids volume for disposal. Results showed that aeration increased the effectiveness of gamma radiation. The efficiency of sludge solubilization with aeration was increased by around 25% compared to that without aeration at an irradiation dose of 2.5-9 kGy. The soluble protein, polysaccharide and humic (like) substance concentrations were higher under aerated conditions. With aeration the overall reaction appears to be oxidative as evidenced by the higher nitrate and nitrite ion concentrations in solution.

  9. Irradiation-induced localization of IL-12-expressing mesenchymal stem cells to enhance the curative effect in murine metastatic hepatoma.

    PubMed

    Jeong, Keun-Yeong; Lee, Eun-Jung; Kim, Su Jin; Yang, Seung-Hyun; Sung, Young Chul; Seong, Jinsil

    2015-08-01

    Irradiation in conjunction with gene therapy is considered for efficient cancer treatment. Mesenchymal stem cells (MSCs), due to their irradiation-promotable tumor tropism, are ideal delivery vehicles for gene therapy. In this study, we investigated whether treatment with radiation and interleukin (IL)-12-expressing MSCs (MSCs/IL-12) exerts improved antitumor effects on murine metastatic hepatoma. HCa-I and Hepa 1-6 cells were utilized to generate heterotopic murine hepatoma models. Tumor-bearing mice were treated with irradiation or MSCs/IL-12 alone, or a combination. Monocyte chemoattractant protein-1 (MCP-1/CCL2) expression was assessed in irradiated hepatoma tissues to confirm a chemotactic effect. Combination treatment strategies were established and their therapeutic efficacies were evaluated by monitoring tumor growth, metastasis and survival rate. IL-12 expression was assessed and the apoptotic activity and immunological alterations in the tumor microenvironment were examined. MCP-1/CCL2 expression and localization of MSCs/IL-12 increased in the irradiated murine hepatoma cells. The antitumor effects, including suppression of pulmonary metastasis and survival rate improvements, were increased by the combination treatment with irradiation and MSCs/IL-12. IL-12 expression was increased in tumor cells, causing proliferation of cluster of differentiation 8(+) T-lymphocytes and natural killer cells. The apoptotic activity increased, indicating that the cytotoxicity of immune cells was involved in the antitumor effect of the combined treatment. Treatment with irradiation and MSCs/IL-12 showed effectiveness in treating murine metastatic hepatoma. IL-12-induced proliferation of immune cells played an important role in apoptosis of tumor cells. Our results suggest that treatment with irradiation and MSCs/IL-12 may be a useful strategy for enhancing antitumor activity in metastatic hepatoma. PMID:25639194

  10. 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.

  11. Counterproductive effect of saccadic suppression during attention shifts.

    PubMed

    Zénon, Alexandre; Corneil, Brian D; Alamia, Andrea; Filali-Sadouk, Nabil; Olivier, Etienne

    2014-01-01

    During saccadic eye movements, the processing of visual information is transiently interrupted by a mechanism known as "saccadic suppression" [1] that is thought to ensure perceptual stability [2]. If, as proposed in the premotor theory of attention [3], covert shifts of attention rely on sub-threshold recruitment of oculomotor circuits, then saccadic suppression should also occur during covert shifts. In order to test this prediction, we designed two experiments in which participants had to orient towards a cued letter, with or without saccades. We analyzed the time course of letter identification score in an "attention" task performed without saccades, using the saccadic latencies measured in the "saccade" task as a marker of covert saccadic preparation. Visual conditions were identical in all tasks. In the "attention" task, we found a drop in perceptual performance around the predicted onset time of saccades that were never performed. Importantly, this decrease in letter identification score cannot be explained by any known mechanism aligned on cue onset such as inhibition of return, masking, or microsaccades. These results show that attentional allocation triggers the same suppression mechanisms as during saccades, which is relevant during eye movements but detrimental in the context of covert orienting. PMID:24466181

  12. 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.

  13. Neutron and gamma irradiation effects on power semiconductor switches

    SciTech Connect

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

    1994-09-01

    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.

  14. 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. PMID:25728227

  15. Precompaction irradiation effects: Particles from an early active sun?

    NASA Technical Reports Server (NTRS)

    Caffee, M. W.; Goswami, J. N.; Hohenberg, C. M.; Swindle, T. D.

    1986-01-01

    Two recent studies have shown that solar flare irradiated grains from Murchison and Kapoeta have excess spallogenic Ne-21 compared to unirradiated grains, indicating large precompaction particle irradiation effects. The quantity of cosmogenic neon in these grains presents serious difficulties for either galactic cosmic ray or normal solar flare sources. In the first study it was suggested that the effect might be the result of exposure to an early active sun. The more recent experiment both confirms the earlier results and provides constraints on the characteristic energy spectrum on the irradiation. The first results were obtained from Murchison olivines and Kapoeta pyroxenes by mass spectrometric analysis of sets of grains selected on the basis of the presence or absence of solar flare particle tracks. In the second work plagioclase feldspar grains from Kapoeta were studied.

  16. 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.

  17. 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.

  18. 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.

  19. Neutron irradiation effects on the microstructural development of tungsten and tungsten alloys

    NASA Astrophysics Data System (ADS)

    Hasegawa, Akira; Fukuda, Makoto; Yabuuchi, Kiyohiro; Nogami, Shuhei

    2016-04-01

    Data on the microstructural development of tungsten (W) and tungsten rhenium (Re) alloys were obtained after neutron irradiation at 400-800 °C in the Japan Materials Testing Reactor (JMTR), the experimental fast test reactor Joyo, and the High Flux Isotope Reactor (HFIR) for irradiation damage levels in the range of 0.09-1.54 displacement per atom (dpa). Microstructural observations showed that a small amount of Re (3-5%) in W-Re alloys is effective in suppressing void formation. In W-Re alloys with Re concentrations greater than 10%, acicular precipitates are the primary structural defects. In the HFIR-irradiated specimen, in which a large amount of Re was expected to be produced by the nuclear transmutation of W to Re because of the reactor's high thermal neutron flux, voids were not observed even in pure W. The synergistic effects of displacement damage and solid transmutation elements on microstructural development are discussed, and the microstructural development of tungsten materials utilized in fusion reactors is predicted.

  20. Effect of Milling Process on the Electron Spin Resonance Center Formation in Pyrex Glass by Gamma-Ray Irradiation

    NASA Astrophysics Data System (ADS)

    Hirai, Makoto; Ikeya, Motoji

    2004-08-01

    Ball-milled Pyrex glass (Corning 7740) was irradiated by gamma-rays to a dose of 30 kGy to investigate the milling effect on the formation of paramagnetic centers with ESR. The formation efficiency of E' centers was increased markedly while that of boron oxygen hole centers (BOHCs) was suppressed by 40%. An annealing experiment showed that the milling process makes BOHCs unstable, which may be the reason for the suppression. Reduction in the ESR intensity, after etching with hydrofluoric acid, clarified that both types of center are concentrated in the near-surface region in different ratios. The milling effect on E' center formation can be explained by the formation of oxygen vacancies in the near-surface region. A similar effect has already been observed in quartz. By contrast, the suppression of BOHC formation in the bulk region needs to be described by a new mechanism. We assume that internal elastic stress induced in the milled grains suppresses BOHC formation. Internal stress in the thermally tempered glass (TTG) was relieved by breaking it to submillimeter size. The observed dependence of the BOHC formation efficiency on grain size allowed us to estimate that the suppression rate per 1 MPa is more than 0.4%, which is consistent with the milling effect assuming a stress of 100 MPa.

  1. α-Tocopherol protects keratinocytes against ultraviolet A irradiation by suppressing glutathione depletion, lipid peroxidation and reactive oxygen species generation

    PubMed Central

    WU, CHI-MING; CHENG, YA-LI; DAI, YOU-HUA; CHEN, MEI-FEI; WANG, CHEE-CHAN

    2014-01-01

    This study aimed to investigate whether α-tocopherol is able to protect keratinocytes against ultraviolet A (UVA) radiation by increasing glutathione (γ-glutamylcysteinylglycine; GSH) levels or decreasing lipid peroxidation and reactive oxygen species (ROS) generation. The cell survival fraction was 43.6% when keratinocytes were irradiated with UVA at a dose of 8 J/cm2. α-Tocopherol was added prior to UVA irradiation and the cell viability was assayed. The cell survival fractions were 60.2, 77.1, 89.0, 92.9 and 96.2% when α-tocopherol was added at concentrations of 2.9, 5.9, 8.8, 11.8 and 14.7 IU/ml, respectively. These results suggested that α-tocopherol is capable of protecting keratinocytes against UVA irradiation. Furthermore, the levels of GSH, lipid peroxidation and ROS were measured. The levels of GSH were 0.354 and 0.600 mmol/g protein in keratinocytes irradiated with UVA (8 J/cm2) and in non-irradiated cells, respectively, whereas they were 0.364, 0.420, 0.525, 0.540 and 0.545 mmol/g protein when α-tocopherol was added at concentrations of 2.9, 5.9, 8.8, 11.8 and 14.7 IU/ml, respectively. The levels of lipid peroxidation were 20.401 or 5.328 μmol/g [malondialdehyde (MDA)/protein] in keratinocytes irradiated with UVA (8 J/cm2) and in non-irradiated cells, respectively, whereas they were 11.685, 6.544, 5.847, 4.390 and 2.164 μmol/g (MDA/protein) when α-tocopherol was added at concentrations of 2.9, 5.9, 8.8, 11.8 and 14.7 IU/ml, respectively. The levels of ROS were 3,952.17 or 111.87 1/mg protein in keratinocytes irradiated with UVA (8 J/cm2) and in non-irradiated cells, respectively, whereas they were 742.48, 579.36, 358.16, 285.63 and 199.82 1/mg protein when α-tocopherol was added at concentrations of 2.9, 5.9, 8.8, 11.8 and 14.7 IU/ml, respectively. These findings suggested that α-tocopherol protects keratinocytes against UVA irradiation, possibly through increasing the levels of GSH or decreasing the levels of lipid peroxidation and ROS

  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 Central

    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 × 108 dm3 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. PMID:25212600

  3. Effect of UV-C Irradiation on Nutraceuticals in Blueberries

    Technology Transfer Automated Retrieval System (TEKTRAN)

    UV-C treatment has been shown to reduce decay of fruits after harvest. However, little information is available on the influence of UV-C illumination on changes of nutraceutical content in fruits. This study was initiated to investigate the effect of UV-C irradiation on total phenolics, total anth...

  4. 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.

  5. Electron irradiation effects in epitaxial InP solar cells

    NASA Technical Reports Server (NTRS)

    Pearsall, N. M.; Robson, N.; Sambell, A. J.; Anspaugh, B.; Cross, T. A.

    1991-01-01

    Performance data for InP-based solar cells after irradiation with 1-MeV electrons up to a fluence of 1 x 1016 e/cm2 are presented. Three InP cell structures are considered. Two of these have epitaxially grown active regions, these being a homojunction design and in ITO/InP structure. These are compared with ITO/InP cells without the epitaxial base region. The cell parameter variations, the influence of illumination during irradiation, and the effect on cell spectral response and capacitance measurements are discussed. Substantial performance recovery after thermal annealing at 90 C is reported.

  6. Effects of self-irradiation in plutonium alloys

    DOE PAGESBeta

    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.

  7. Low energy argon ion irradiation surface effects on triglycine sulfate

    NASA Astrophysics Data System (ADS)

    Aragó, Carmen; Plaza, José L.; Marqués, Manuel I.; Gonzalo, Julio A.

    2013-09-01

    An experimental study of the effects of low energy (1-2 keV) argon ion (Ar+) irradiation on Triglycine Sulfate (TGS) has been performed. Ferroelectric parameters, such as the Curie temperature TC determined from the dielectric constant peaks ɛ(T), or the remnant polarization Pr, and coercive field Ec, obtained from the hysteresis loops, show interesting differences between samples irradiated in ferroelectric and paraelectric phases, respectively. The radiation damage seems to be superficial, as observed by AFM microscope, and the surface alteration in both phases becomes eventually notorious when the radiation dosage increases.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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. PMID:10665021

  13. Improving the effectiveness of a low-energy Compton suppression system

    NASA Astrophysics Data System (ADS)

    Britton, R.; Burnett, J. L.; Davies, A. V.; Regan, P. H.

    2013-11-01

    A novel method for collecting and processing coincidence data from a Compton Suppressed Low Energy Photon Spectrometer (LEPS) is presented, greatly simplifying the current setup and extending the suppression abilities of the system. Offline analysis is used, eliminating the need to discard coincidence data when vetoing coincident events with fast-timing electronics. Additional coincident events are identified that are usually missed, and which represent interactions in the active NaI(Tl) shield prior to an interaction in the LEPS detector. By suppressing these events, the Compton Suppression factor was improved by 144% for the 661.66 keV decay line in a 137Cs source. The geometry used for this particular Compton suppression system is highly sensitive to these effects, however similar event profiles are expected in all coincidence systems.

  14. 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.

  15. The effects of suppressing intrusive thoughts on dream content, dream distress and psychological parameters.

    PubMed

    Kröner-Borowik, Tana; Gosch, Stefanie; Hansen, Kathrin; Borowik, Benjamin; Schredl, Michael; Steil, Regina

    2013-10-01

    Suppressing unwanted thoughts can lead to an increased occurrence of the suppressed thought in dreams. This is explainable by the ironic control theory, which theorizes why the suppression of thoughts might make them more persistent. The present study examined the influence of thought suppression on dream rebound, dream distress, general psychiatric symptomatology, depression, sleep quality and perceived stress. Thirty healthy participants (good sleepers) were investigated over a period of 1 week. Half were instructed to suppress an unwanted thought 5 min prior to sleep, whereas the other half were allowed to think of anything at all. Dream content was assessed through a dream diary. Independent raters assessed whether or not the dreams were related to the suppressed target thought. The results demonstrated increased target-related dreams and a tendency to have more distressing dreams in the suppression condition. Moreover, the data imply that thought suppression may lead to significantly increased general psychiatric symptomatology. No significant effects were found for the other secondary outcomes. PMID:23679926

  16. 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.

  17. The N1-suppression effect for self-initiated sounds is independent of attention

    PubMed Central

    2013-01-01

    Background If we initiate a sound by our own motor behavior, the N1 component of the auditory event-related brain potential (ERP) that the sound elicits is attenuated compared to the N1 elicited by the same sound when it is initiated externally. It has been suggested that this N1 suppression results from an internal predictive mechanism that is in the service of discriminating the sensory consequences of one’s own actions from other sensory input. As the N1-suppression effect is becoming a popular approach to investigate predictive processing in cognitive and social neuroscience, it is important to exclude an alternative interpretation not related to prediction. According to the attentional account, the N1 suppression is due to a difference in the allocation of attention between self- and externally-initiated sounds. To test this hypothesis, we manipulated the allocation of attention to the sounds in different blocks: Attention was directed either to the sounds, to the own motor acts or to visual stimuli. If attention causes the N1-suppression effect, then manipulating attention should affect the effect for self-initiated sounds. Results We found N1 suppression in all conditions. The N1 per se was affected by attention, but there was no interaction between attention and self-initiation effects. This implies that self-initiation N1 effects are not caused by attention. Conclusions The present results support the assumption that the N1-suppression effect for self-initiated sounds indicates the operation of an internal predictive mechanism. Furthermore, while attention had an influence on the N1a, N1b, and N1c components, the N1-suppression effect was confined to the N1b and N1c subcomponents suggesting that the major contribution to the auditory N1-suppression effect is circumscribed to late N1 components. PMID:23281832

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

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

    Tungsten samples were irradiated by neutrons in the High Flux Isotope Reactor (HFIR), Oak Ridge National Laboratory at reactor coolant temperatures of 50-70 °C to low displacement damage of 0.025 and 0.3 dpa. 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 the 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 the 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 trapped in bulk (at least 50 µm depth for 0.025 dpa and 35 µm depth for 0.3 dpa) at 500 °C cases even in the relatively low ion fluence of 1026 m-2.

  19. 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.

  20. Exploring the boundary conditions of unconscious numerical priming effects with continuous flash suppression.

    PubMed

    Hesselmann, G; Darcy, N; Sterzer, P; Knops, A

    2015-01-01

    The scope and limits of unconscious processing are a controversial topic of research in experimental psychology. Particularly within the visual domain, a wide range of paradigms have been used to experimentally manipulate perceptual awareness. A recent study reported unconscious numerical processing during continuous flash suppression (CFS), which is a powerful variant of interocular suppression and disrupts the conscious perception of visual stimuli for up to seconds. Since this finding of a distance-dependent priming effect contradicts earlier results showing that interocular suppression abolishes semantic processing, we sought to investigate the boundary conditions of this effect in two experiments. Using statistical analyses and experimental designs that precluded an effect of target numerosity, we found evidence for identity priming, but no conclusive evidence for distance-dependent numerical priming under CFS. Our results suggest that previous conclusions on high-level numerical priming under interocular suppression may have been premature. PMID:25460241

  1. 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.

  2. 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.

  3. Effects of stimulus frequency on vocal suppression in neonates.

    PubMed

    Watterson, T; Riccillo, S

    1985-04-01

    Three groups, each composed of 15 normal neonates, were exposed to different narrowband stimuli, all at 80 db SPL, representing low frequencies (peak level at 1 kc/s of 75 db, half-power bandwidth of 180 c/s), middle frequencies (peak level at 3 kc/s of 75 db, half-power bandwidth of 300 c/s), and high frequencies (peak level at 6 kc/s of 69 db, half-power bandwidth of 1 kc/s). Each S in each group was tested with the appropriate 4-min control condition for each S where a stimulus was not presented. For each group, Ss cried significantly less during the stimulus than for the control condition. There was a trend for suppression of crying to decrease as stimulus frequency increased (mean suppression of crying during the noise presentations, relative to the crying during the control conditions, were 148.3, 125.2, and 111.5 secs for the frequencies in order), but the differences among the groups were not significant. This suggests that neonates do not hear appreciably better at some frequencies than at others, and also that neonates do not necessarily interact differently with different stimuli because of frequency content. It seems, therefore, that neonates respond on a stimulus-response basis that is proportional in strength to stimulus level and spectral complexity. Loud complex noises are the strongest stimuli because they result in maximum neural excitation. However, narrowband noises can be used to indicate something of the neonate's frequency sensitivity. PMID:3842140

  4. 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.

  5. 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.

  6. 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

  7. Effects of electron irradiation on LDPE/MWCNT composites

    NASA Astrophysics Data System (ADS)

    Yang, Jianqun; Li, Xingji; Liu, Chaoming; Rui, Erming; Wang, Liqin

    2015-12-01

    In this study, mutiwalled carbon nanotubes (MWCNTs) were incorporated into low density polyethylene (LDPE) in different concentrations (2%, 4% and 8%) using a melt blending process. Structural, thermal stability and tensile property of the unirradiated/irradiated LDPE/MWCNT composites by 110 keV electrons were investigated by means of scanning electron microscopy (SEM), small angle X-ray scattering (SAXS), Raman spectroscopy, electron paramagnetic resonance (EPR) spectroscopy, thermogravimetric analysis (TGA) and uniaxial tensile techniques. Experimental results show that the addition of MWCNTs obviously increases the ultimate tensile strength of LDPE and decreases the elongation at break, which is attributed to the homogeneous distribution of the MWCNTs in LDPE and intense interaction between MWCNTs and LDPE matrix. Also, the electron irradiation further increases the ultimate tensile strength of LDPE/MWCNT composites, which can be ascribed to the more intense interaction between MWCNTs and LDPE matrix, and the formation of crosslinking sites in LDPE matrix induced by the electron irradiation. The addition of MWCNTs significantly enhances thermal stability of the LDPE due to the hindering effect and the scavenging free radicals, while the electron irradiation decreases thermal stability of the LDPE/MWCNT composites since the structure of the MWCNTs and LDPE matrix damages.

  8. Effects of irradiation for cervical cancer on subsequent breast cancer

    SciTech Connect

    Harlan, L.C.M.

    1985-01-01

    Previous research suggests that cervical cancer patients have a lower risk of breast cancer than women in the general population. Possible explanations include opposing risk factors for cervical cancer and breast cancer, the effect of irradiation used to treat cervical cancer, or both. The purpose of this study was to explore the relationship between irradiation for cervical cancer and the subsequent development of breast cancer. There was no statistically significant relationship between radiation to the ovarian area and the risk of breast cancer in this study. However, the results were consistent with a 19% reduction in risk for women irradiated for cervical cancer when compared to nonirradiated women. In a dose-response analysis, there was a nonsignificant trend of decreased risk of breast cancer with increased radiation up to 1800 rad. There was no consistent pattern for higher doses. The trend, although nonsignificant, differed by age. Women <60 years of age at irradiation were generally at a lower risk of breast cancer than nonirradiated women. Women over 59 years were at an increased risk. There are some potentially important findings from this study which might influence medical care. These should be examined in the larger International Radiation Study.

  9. 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.

  10. Hall effect measurements on proton-irradiated ROSE samples

    SciTech Connect

    Biggeri, U.; Bruzzi, M.; Borchi, E.

    1997-01-01

    Bulk samples obtained from two wafers of a silicon monocrystal material produced by Float-Zone refinement have been analyzed using the four-point probe method. One of the wafers comes from an oxygenated ingot; two sets of pure and oxygenated samples have been irradiated with 24 GeV/c protons in the fluence range from 10{sup 13} p/cm{sup 2} to 2x10{sup 14} p/cm{sup 2}. Van der Pauw resistivity and Hall coefficient have been measured before and after irradiation as a function of the temperature. A thermal treatment (30 minutes at 100C) has been performed to accelerate the reverse annealing effect in the irradiated silicon. The irradiated samples show the same exponential dependence of the resistivity and of the Hall coefficient on the temperature from 370K to 100K, corresponding to the presence of radiation-induced deep energy levels around 0.6-0.7eV in the silicon gap. The free carrier concentrations (n, p) have been evaluated in the investigated fluence range. The inversion of the conductivity type from n to p occurred respectively at 7x10{sup 13} p/cm{sup 2} and at 4x10{sup 13} p/cm{sup 2} before and after the annealing treatment, for both the two sets. Only slight differences have been detected between the pure and oxygenated samples.

  11. 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.

  12. 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.

  13. [Therapeutic Effects of Multipotent Mesenchymal Stromal Cells after Irradiation].

    PubMed

    Kalmykova, N V; Alexandrova, S A

    2016-01-01

    Multipotent mesenchymal stromal cells (MSC) are now considered to be a perspective multifunctional treatment option for radiation side effects. At present.a great number of sufficient evidence has been collected in favor of therapeutic effects of MSCs in acute radiation reactions. It has been shown that MSC-based products injected locally or systemically have therapeutic effects on irradiated organs and tissues. This review presents summarized experimental and clinical data about protective and regenerative effects of MSCs on different radiation-injured organs and tissues; the main probable therapeutic mechanisms of their action are also discussed. PMID:27534063

  14. 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.

  15. Lipoic acid suppression of neutrophil respiratory burst: effect of NADPH.

    PubMed

    O'Neill, Heidi C; Rancourt, Raymond C; White, Carl W

    2008-02-01

    Lipoic acid (LA) and its reduced product dihydrolipoic acid (DHLA) are potent antioxidants with capacity to scavenge reactive oxygen species (ROS) and recycle endogenous antioxidants. LA may increase cellular glutathione (GSH), an antioxidant lacking in the lung's epithelial lining fluid in lung disorders such as idiopathic pulmonary fibrosis (IPF). Neutrophils (PMN) are key innate responders and are pivotal in clearing bacterial infection, therefore it is crucial to understand the impact LA may have on their function. Circulating neutrophils were isolated from healthy volunteers and pretreated with LA or diluent. Cells were subsequently activated with phorbol 12-myristate 13-acetate (PMA, 100 ng/ml) to induce ROS production. SOD-inhibitable reduction of acetylated cytochrome c demonstrated the PMA-dependent respiratory burst was suppressed by LA. Oxygen consumption also was diminished when PMA-stimulated cells were pretreated with LA. PMN respiratory burst was partially restored by addition of NADPH but not other pyridine nucleotides. LA did not inhibit glucose-6-phosphate dehydrogenase activity of PMN. These data together suggest that the reduction of LA to DHLA using cellular NADPH may limit the capacity of the PMN NADPH oxidase to produce superoxide. Further studies will be required to determine if LA can diminish excessive superoxide produced by PMN and/or alveolar macrophages in IPF or relevant disease models in vivo. PMID:18158760

  16. 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.

  17. 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. PMID:26919658

  18. Effect of free electron laser (FEL) irradiation on tooth dentine

    NASA Astrophysics Data System (ADS)

    Ogino, Seiji; Awazu, Kunio; Tomimasu, Takio

    1996-12-01

    Free electron laser (FEL) gives high efficiency for the photo-induced effects when the laser is tuned to the absorption maximum of target materials. The effect on dentine was investigated using the FEL tuned to 9.4 micrometers , which is an absorption maximum of phosphoric acid in infrared region. As a result, irradiated dentine surface which was amorphous had changed to the recrystalized structure by the spectroscopic analysis of IR absorption and x-ray diffraction. Furthermore, the atomic ratio of P/Ca had reduced from 0.65 to 0.60. These results indicated that 9.4micrometers -FEL irradiation caused the selective ablation of phosphoric acid ion and the reconstruction of disordered atoms.

  19. 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.

  20. Effects of glycyrrhizin on UVB-irradiated melanoma cells.

    PubMed

    Rossi, Tiziana; Benassi, Luisa; Magnoni, Cristina; Ruberto, Antonio Ippazio; Coppi, Andrea; Baggio, Giosué

    2005-01-01

    It is known that liquorice root is rich in compounds which exert several pharmacological actions. In the present study, we evaluated the effect of glycyrrhizin (the main constituent of liquorice root) and of its metabolite aglycone, 18beta-glycyrrhetinic acid, on UVB-irradiated human melanoma cells: SKMEL-2 from metastatic tissue and SKMEL-28 from primary malignant melanoma. Tests performed (Trypan blue exclusion test, MTT and Western blot) showed that glycyrrhizin is not toxic for both types of cells. In SKMEL-28 cells, Bcl-2 expression was low after UVB irradiation, but it was increased when treated with glycyrrhizin. On the contrary, in the SKMEL-2 cell culture, Bcl-2 expression was not modified by the substances under study. The results show that glycyrrhizin treatment might offer protection from the damage induced in humans by UVB radiation, while it seems to be ineffective on metastatic cells. Further studies must be performed to understand the mechanism of the protective effect. PMID:15796192

  1. 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. PMID:25468991

  2. Suppression of Background Odor Effect in Odor Sensing System Using Olfactory Adaptation Model

    NASA Astrophysics Data System (ADS)

    Ohba, Tsuneaki; Yamanaka, Takao

    In this study, a new method for suppressing the background odor effect is proposed. Since odor sensors response to background odors in addition to a target odor, it is difficult to detect the target odor information. In the conventional odor sensing systems, the effect of the background odors are compensated by subtracting the response to the background odors (the baseline response). Although this simple subtraction method is effective for constant background odors, it fails in the compensation for time-varying background odors. The proposed method for the background suppression is effective even for the time-varying background odors.

  3. 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.

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

    DOE PAGESBeta

    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. 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

  5. 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.

  6. Increasing self-regulatory strength can reduce the depleting effect of suppressing stereotypes.

    PubMed

    Gailliot, Matthew T; Plant, E Ashby; Butz, David A; Baumeister, Roy F

    2007-02-01

    Three longitudinal studies and one correlational study tested the hypothesis that increasing self-regulatory strength by regular self-regulatory exercise would reduce the intrapsychic costs of suppressing stereotypes. Participants tried to resist using stereotypes while describing or talking to a stimulus person. Participants whose habitual motivation to suppress stereotypes was low exhibited impaired Stroop and anagram performance after the suppression task, presumably because of self-regulatory depletion (i.e., a reduction of self-regulatory strength following prior use). Two weeks of self-regulation exercises (such as using one's nondominant hand or refraining from cursing) eliminated this effect. These findings indicate that self-regulatory exercise can improve resistance to self-regulatory depletion and, consequently, people can suppress stereotypes without suffering subsequent decrements in task performance. PMID:17259587

  7. 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.

  8. Cronin Effect Versus High-pT Suppression in Saturation Physics

    NASA Astrophysics Data System (ADS)

    Kharzeev, Dmitri; Kovchegov, Yuri

    2003-10-01

    We discuss the interplay of Cronin effect and high-pT suppression in particle production in DA collisions. We concentrate on gluon production at mid-rapidity. The production cross section has effects of multiple rescatterings in the nucleus and quantum evolution in energy included in it by an exact calculation performed in earlier work. We show that the resulting formula turns out to have a strong Cronin enhancement in the quasi-classical limit of McLerran-Venugopalan model. However effects of quantum evolution in energy modify this behavior possibly introducing suppression of high-pT particles.

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

    DOE PAGESBeta

    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

  10. 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.

  11. Studies on the mechanism of systemic suppression of contact hypersensitivity by UVB radiation. II. Differences in the suppression of delayed and contact hypersensitivity in mice.

    PubMed

    Kripke, M L; Morison, W L

    1986-05-01

    Exposing mice to UV radiation in the UVB range (280-320 nm) causes a selective immune suppression that contributes to the development of UVB-induced skin cancers. Among the immune responses suppressed by UVB irradiation are contact and delayed hypersensitivity reactions to haptens administered at unexposed sites. In these studies we provide evidence that delayed and contact hypersensitivity to the same hapten are not equivalent reactions and that they are suppressed in UVB-irradiated mice by 2 different mechanisms. This conclusion is based on the findings that: suppression of contact hypersensitivity could not be overcome by immunizing UVB-irradiated mice with hapten-coupled antigen-presenting cells derived from normal donors; and treatment of UVB-irradiated mice with methylprednisolone before immunization prevented the suppression of delayed hypersensitivity but had no effect on the suppression of contact hypersensitivity. The decreased ability to induce contact hypersensitivity in UVB-irradiated mice could be transferred to x-irradiated mice by reconstituting them with spleen cells from UVB-irradiated donors. The induction of hapten-specific suppressor cells, however, required both UVB irradiation and priming with hapten. Based on these results, we postulate that UVB irradiation induces a population of suppressor-inducer cells with specificity for a modified skin antigen and that this antigen serves as a carrier molecule for haptens that induce contact hypersensitivity and for tumor-specific transplantation antigens on UVB-induced tumors. PMID:3745963

  12. Sequential effects of irradiation on the pulmonary surfactant system. [Mice

    SciTech Connect

    Shapiro, D.L.; Finkelstein, J.N.; Penney, D.P.; Siemann, D.W.; Rubin, P.

    1982-05-01

    This study examines the effect of irradiation on lung surfactant synthesis and secretion in mice. Animals were irradiated with 650, 1300, or 1950 rad and morphological and biochemical indices of surfactant system function were followed for 18 weeks. No changes were seen at 650 rad; the results at 1300 and 1950 rad were virtually identical. Increased amounts of alveolar surfactant phospholipid were measureable by 24 hours. This persisted for four weeks and returned to normal by 18 weeks. Tissue surfactant phospholipid was initially reduced, returned to normal by four weeks and was increased at 18 weeks. At 18 weeks there was increased incorporation of surfactant precursor and increased production of alveolar surfactant. These biochemical changes were reflected in morphologic alterations showing release of lamellar body contents into alveoli in the first week and an increase in lamellar bodies in type II pneumocytes by 18 weeks. Elevated tissue protein levels and morphologic evidence of increased collagen formation were also found at 18 weeks. These findings indicate effects of irradiation on the pulmonary surfactant system and have important implications for the pathogenesis and potential therapy of radiation pneumonitis.

  13. 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.

  14. 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.

  15. Heavy ion irradiation effects of brannerite-type ceramics

    NASA Astrophysics Data System (ADS)

    Lian, J.; Wang, L. M.; Lumpkin, G. R.; Ewing, R. C.

    2002-05-01

    Brannerite, UTi 2O 6, occurs in polyphase Ti-based, crystalline ceramics that are under development for plutonium immobilization. In order to investigate radiation effects caused by α-decay events of Pu, a 1 MeV Kr + irradiation on UTi 2O 6, ThTi 2O 6, CeTi 2O 6 and a more complex material, composed of Ca-containing brannerite and pyrochlore, was performed over a temperature range of 25-1020 K. The ion irradiation-induced crystalline-to-amorphous transformation was observed in all brannerite samples. The critical amorphization temperatures of the different brannerite compositions are: 970 K, UTi 2O 6; 990 K, ThTi 2O 6; 1020 K, CeTi 2O 6. The systematic increase in radiation resistance from Ce-, Th- to U-brannerite is related to the difference of mean atomic mass of A-site cation in the structure. As compared with the pyrochlore structure-type, brannerite phases are more susceptible to ion irradiation-induced amorphization. The effects of structure and chemical compositions on radiation resistance of brannerite-type and pyrochlore-type ceramics are discussed.

  16. Effects of gamma irradiation on the colour of pigments

    NASA Astrophysics Data System (ADS)

    Negut, D. C.; Ponta, C. C.; Georgescu, Rodica M.; Moise, I. V.; Niculescu, Gh.; Lupu, A. I. M.

    2007-07-01

    The aim of this paper is to investigate the influence of gamma irradiation process on the colour of painted wood panels. Insects and micro-organisms are frequently identified enemies of cultural objects from museums and archives. Based on its biocide effect, gamma radiation could be used for decontamination and conservation purposes. Important advantages can be mentioned in its favour: no toxic or radioactive residues remained in the treated item; large amount of objects can be treated quickly; excellent reliability; attractive cost. In case of emergency radiation treatment in industrial facilities is probably the only method that can be used. There is also a potential side-effect. Interaction of gamma rays with any substance may change its chemical and physical properties. The change is proportional with the irradiation dose. In the case of paintings, eventually colour changes have to be evaluated. Such an approach actually establishes irradiation treatment limitations. A portable integrating sphere spectrophotometer was used for colour measurements. The results of colour analysis before and after the radiation treatment of the painted wood panels are reported and discussed.

  17. 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.

  18. 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.

  19. Effects of self-irradiation in plutonium alloys

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    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. Effects of. gamma. irradiation on cartilage matrix calcification

    SciTech Connect

    Nijweide, P.J.; Burger, E.H.; van Delft, J.L.; Kawilarange-de Haas, E.W.M.; Wassenaar, A.M.; Mellink, J.H.

    1980-10-01

    The effect of ..gamma.. irradiation on cartilage matrix calcification was studied in vitro. Metatarsal bones of 14- to 17-day-old embryonic mice were dissected and cultured under various conditions. Prior to culture, half of the metatarsal bones received absorbed doses of 1.0 to 30.0 Gy ..gamma.. radiation. Their paired counterparts served as controls. Irradiation inhibited longitudinal growth and calcification of the cartilage matrix during culture. In addition, a number of histological changes were noted. The inhibition of matrix calcification appeared to be due to an inhibition of the intracellular calcium accumulation. The formation of extracellular calcification foci and the growth of the calcified area already present at the moment of explanation were not inhibited during culture.

  1. Hall effect analysis in irradiated silicon samples with different resistivities

    SciTech Connect

    Borchi, E.; Bruzzi, M.; Pirollo, S. |; Dezillie, B.; Li, Z.; Lazanu, S.

    1999-08-01

    The changes induced by neutron irradiation in n- and p-type silicon samples with starting resistivities from 10 {Omega}-cm up to 30 K{Omega}-cm, grown using different techniques, as Float-Zone (FZ), Czochralski (CZ) and epitaxial, have been analyzed by Van der Pauw and Hall effect measurements. Increasing the fluence, each set of samples evolved toward a quasi-intrinsic p-type material. This behavior has been explained in the frame of a two-level model, that considers the introduction during irradiation of mainly two defects. A deep acceptor and a deep donor, probably related to the divacancy and to the C{sub i}O{sub i} complex, are placed in the upper and lower half of the forbidden gap, respectively. This simple model explains quantitatively the data on resistivity and Hall coefficient of each set of samples up to the fluence of {approx} 10{sup 14} n/cm{sup 2}.

  2. 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

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

    NASA Astrophysics Data System (ADS)

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

    2013-08-01

    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.

  4. 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.

  5. 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.

  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. Using the quantum Zeno effect for suppression of decoherence

    NASA Astrophysics Data System (ADS)

    Kondo, Yasushi; Matsuzaki, Yuichiro; Matsushima, Kei; Filgueiras, Jefferson G.

    2016-01-01

    Projective measurements are an essential element of quantum mechanics. In most cases, they cause an irreversible change of the quantum system on which they act. However, measurements can also be used to stabilize quantum states from decay processes, which is known as the quantum Zeno effect (QZE). Here, we demonstrate this effect for the case of a superposition state of a nuclear spin qubit, using an ancilla to perform the measurement. As a result, the quantum state of the qubit is protected against dephasing without relying on an ensemble nature of NMR experiments. We also propose a scheme to protect an arbitrary state by using QZE.

  8. 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

  9. 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.

  10. Brief Report: Signals Enhance the Suppressive Effects of Noncontingent Reinforcement

    ERIC Educational Resources Information Center

    Ringdahl, Joel E.; Call, Nathan A.; Christensen, Tory; Boelter, Eric W.

    2010-01-01

    The effects of noncontingent reinforcement (NCR) schedules on responding were assessed across two parameters: presence of signal and schedule density. Results indicated that signaled NCR schedules were correlated with greater overall reductions in responding and quicker reductions relative to NCR schedules without a signal. The clinical…

  11. Biochar suppression of N2O emissions from an agricultural soil: effects and potential mechanisms

    NASA Astrophysics Data System (ADS)

    Case, S. D. C.; Whitaker, J.; McNamara, N. P.; Reay, D. S.

    2012-04-01

    Biochar is biomass that has been heated in a low-oxygen environment to between 350 and 800°C that is subsequently used as a soil amendment. As well as benefits to soil fertility, biochar has potential as a tool to mitigate climate change on a large scale due to its recalcitrance, high carbon content and observed effect of reducing soil greenhouse gas emissions. Previous studies have shown that biochar-amended soil may emit less nitrous oxide (N2O) than soil alone. Our aim was to investigate the effect of fresh, hardwood biochar on N2O emissions from a clay agricultural soil from Lincolnshire, United Kingdom with a combination of field and laboratory studies. We then investigated the mechanism to try to explain the observed suppression of N2O emissions with biochar. In biochar-amended field plots, quarterly greenhouse gas measurements over two years have recorded one occurrence of significant suppression of N2O emissions (80%), with other measurements showing generally low emissions of N2O across all treatments. In laboratory experiments, biochar suppressed N2O emissions following simulated rainfall events in a low-N agricultural soil (72 % suppression), in the same field-moist soil incubated with biochar in the field for 10 months (40 % suppression) and in a relatively high-N soil from a neighbouring field (83 % suppression). We hypothesised that biochar amendment may suppress soil N2O emissions by increasing the water holding capacity (WHC) of the soil, thus rendering the biochar-amended soil less anaerobic compared to control soil at the same gravimetric water content. Water was added to raise soil to the same WHC (87 %) with and without biochar at a range of addition rates. Biochar significantly suppressed N2O emissions with 5 % biochar addition by 67 % and 10 % biochar addition by 98 %. We concluded that the increased WHC of biochar-amended soil could not explain the suppression of N2O emissions. Subsequently, we formulated two hypotheses: (1) that biochar may

  12. Mechanisms of suppression in mixed allogeneic chimeras

    SciTech Connect

    Sykes, M.; Sachs, D.H.

    1988-08-01

    Cells with the ability to suppress cytotoxic T lymphocyte generation are found in the spleens of whole-body-irradiated (WBI) mixed allogeneic and syngeneic bone marrow transplant recipients in the early weeks after BMT. Previous studies have indicated that suppression is mediated by null cells similar to natural suppressor (NS) cells (1), and have ruled out several possible trivial explanations for the suppressive effect. We report here the results of additional experiments designed to assess possible mechanisms of suppression. We compared the cell populations after 5 days' incubation of cultures containing normal responding splenocytes plus irradiated allogeneic stimulator cells, with or without a cocultured suppressive chimeric splenocyte population. The data indicate that total viable cell yields are only slightly reduced, if at all, in suppressed cultures, but that the proportion of T cells is markedly reduced as measured at the end of the incubation period. Splenocytes from early BMT recipients do not appear to proliferate during the suppression of a mixed lymphocyte culture, and such populations represent only 15% of cells at the end of the 5-day incubation period. Suppression is strongest when the suppressive population is added at the initiation of MLC, and is lost if addition is delayed beyond day 3. Suppression can be overcome by T cell growth factor (TCGF)--and, to a lesser extent, by recombinant IL-2 (rIL-2), although resting suppressive populations do not consume appreciable amounts of these lymphokines. These results therefore suggest that suppression in MLC may occur primarily during the induction of helper T lymphocytes.

  13. 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. PMID:23649341

  14. Effects of impurities on one-dimensional migration of interstitial clusters in iron under electron irradiation

    SciTech Connect

    Satoh, Y.; Matsui, H.; Hamaoka, T.

    2008-03-01

    One-dimensional (1D) migration of small interstitial-type dislocation loops was studied for Fe specimens of different purities at room temperature under electron irradiation using a high-voltage electron microscope. Most 1D migration appeared as discrete jumps (stepwise positional changes) at irregular intervals, and sometimes involved back and forth motion between certain points. The distribution of jump distances extended to over 100 nm in high-purity specimens; it was less than 30 nm in low-purity specimens. Jump frequency was almost proportional to electron beam intensity and was on the same order as the rate of atomic displacement by electron irradiation. Molecular dynamics simulation suggested the suppression of 1D migration of an interstitial cluster (7i) by an oversized solute Cu atom located in the dilatational strain field of the cluster. We proposed that the 1D jump process occurs in the following sequence: (1) interstitial clusters are in a stationary state due to trapping effect by impurity atoms, (2) incident electrons hit and displace impurity atom to cause detrapping, (3) liberated clusters cause fast 1D migration at low activation energy, and (4) the cluster is trapped again by another impurity. Experimental results were analyzed and discussed in terms of the proposed model.

  15. 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.

  16. 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.

  17. The effects of sexual assault-related intrusion suppression in the laboratory and natural environment.

    PubMed

    Rosenthal, M Zachary; Follette, Victoria M

    2007-01-01

    Individuals with a history of sexual victimization often experience enduring intrusive thoughts associated with their assault history. Research suggests that the characteristic ways in which sexually assaulted individuals respond to aversive internal experiences (i.e., thoughts, emotions, etc.) can influence the psychological distress associated with these intrusions. This study investigated the effects of suppressing sexual assault-related intrusions in a sample of 61 female college students with a history of adolescent or adult sexual assault and recent assault-related intrusions. Participants were randomly assigned to suppress or monitor intrusions during a laboratory task and for 48 h outside the laboratory. In contrast to study hypotheses, findings indicated that intrusion monitoring was associated with higher subjective distress than suppression both in the laboratory and in the natural environment. No differences were found for the frequency of intrusions between groups in the laboratory. However, modest evidence for a rebound effect in intrusion frequency was found outside the laboratory. PMID:16580627

  18. The moderating effects of stimulus valence and arousal on memory suppression.

    PubMed

    Marx, Brian P; Marshall, Peter J; Castro, Frank

    2008-04-01

    This study examined the separate and combined effects of stimulus valence and arousal on retrieval inhibition. Participants performed Anderson and Green's (2001) memory suppression task with stimuli varying across dimensions of valence and arousal. Memory was tested through free and cued recall as well as speeded recognition. Results showed that both stimulus valence and arousal influenced the extent to which participants successfully inhibited retrieval, but not in the ways anticipated. Specifically, the strongest inhibition effects were for highly arousing, pleasant words. In addition, unpleasant stimuli that were suppressed were better recalled during both cued and free-recall tasks than pleasant stimuli that were suppressed. Across all tests of memory performance, there were no significant differences between the experimental conditions for highly arousing, unpleasant words. The implications of these findings are discussed. PMID:18410194

  19. An algorithm to evaluate solar irradiance and effective dose rates using spectral UV irradiance at four selected wavelengths.

    PubMed

    Anav, A; Rafanelli, C; Di Menno, I; Di Menno, M

    2004-01-01

    The paper shows a semi-analytical method for environmental and dosimetric applications to evaluate, in clear sky conditions, the solar irradiance and the effective dose rates for some action spectra using only four spectral irradiance values at selected wavelengths in the UV-B and UV-A regions (305, 320, 340 and 380 nm). The method, named WL4UV, is based on the reconstruction of an approximated spectral irradiance that can be integrated, to obtain the solar irradiance, or convoluted with an action spectrum to obtain an effective dose rate. The parameters required in the algorithm are deduced from archived solar spectral irradiance data. This database contains measurements carried out by some Brewer spectrophotometers located in various geographical positions, at similar altitudes, with very different environmental characteristics: Rome (Italy), Ny Alesund (Svalbard Islands, Norway) and Ushuaia (Tierra del Fuego, Argentina). To evaluate the precision of the method, a double test was performed with data not used in developing the model. Archived Brewer measurement data, in clear sky conditions, from Rome and from the National Science Foundation UV data set in San Diego (CA, USA) and Ushuaia, where SUV 100 spectroradiometers operate, were drawn randomly. The comparison of measured and computed irradiance has a relative deviation of about +/-2%. The effective dose rates for action spectra of Erythema, DNA and non-Melanoma skin cancer have a relative deviation of less than approximately 20% for solar zenith angles <50 degrees . PMID:15266087

  20. Early suppression effect in human primary visual cortex during Kanizsa illusion processing: A magnetoencephalographic evidence.

    PubMed

    Chernyshev, Boris V; Pronko, Platon K; Stroganova, Tatiana A

    2016-01-01

    Detection of illusory contours (ICs) such as Kanizsa figures is known to depend primarily upon the lateral occipital complex. Yet there is no universal agreement on the role of the primary visual cortex in this process; some existing evidence hints that an early stage of the visual response in V1 may involve relative suppression to Kanizsa figures compared with controls. Iso-oriented luminance borders, which are responsible for Kanizsa illusion, may evoke surround suppression in V1 and adjacent areas leading to the reduction in the initial response to Kanizsa figures. We attempted to test the existence, as well as to find localization and timing of the early suppression effect produced by Kanizsa figures in adult nonclinical human participants. We used two sizes of visual stimuli (4.5 and 9.0°) in order to probe the effect at two different levels of eccentricity; the stimuli were presented centrally in passive viewing conditions. We recorded magnetoencephalogram, which is more sensitive than electroencephalogram to activity originating from V1 and V2 areas. We restricted our analysis to the medial occipital area and the occipital pole, and to a 40-120 ms time window after the stimulus onset. By applying threshold-free cluster enhancement technique in combination with permutation statistics, we were able to detect the inverted IC effect-a relative suppression of the response to the Kanizsa figures compared with the control stimuli. The current finding is highly compatible with the explanation involving surround suppression evoked by iso-oriented collinear borders. The effect may be related to the principle of sparse coding, according to which V1 suppresses representations of inner parts of collinear assemblies as being informationally redundant. Such a mechanism is likely to be an important preliminary step preceding object contour detection. PMID:27485162

  1. 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

    2016-01-01

    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

  2. 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

  3. 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.

  4. Anger Suppression and Subsequent Pain Behaviors among Chronic Low Back Pain Patients: Moderating Effects of Anger Regulation Style

    PubMed Central

    Quartana, Phillip; Bruehl, Stephen

    2013-01-01

    Background Suppression of anger is linked to subsequent pain intensity among chronic low back patients, but it is not clear whether anger regulation style (trait anger-out, anger-in) moderates these effects or if aroused anger accounts for links between anger regulation style and pain. Method Chronic low back pain patients (N=58) were assigned to Suppression or No Suppression conditions for a task with harassing confederate and then underwent structured pain behavior procedures. Spielberger Anger Expression Inventory tapped trait anger-out (AOS) and anger-in (AIS). Results Regressions tested Emotion Regulation condition × AOS and AIS effects on outcomes. AOS was related to grimacing and sighing for Suppression condition patients. AIS was related negatively to guarding and bracing for Suppression condition patients. Anger report partly mediated effects for AOS and AIS. Conclusions Anger regulation style moderated effects of state anger suppression on subsequent pain behaviors, effects that were partly explained by aroused anger. PMID:21544702

  5. 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.

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

    NASA Astrophysics Data System (ADS)

    Jin, Enze; Niu, Li-Sha; Lin, Enqiang; Song, Xiaoxiong

    2012-05-01

    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.

  7. Effective suppression of acrylamide neurotoxicity by lithium in mouse.

    PubMed

    Song, Lingzhen; Wang, Jiutao; Zhang, Wei; Yan, Runchuan; Hu, Xinde; Chen, Shulin; Zhao, Shanting

    2014-11-01

    The primary objective of this investigation was to assess the neuroprotective efficacy of lithium in an acrylamide (ACR)-induced neuropathy model in mice. In this study, Kunming male mice were administered ACR (25 mg/kg bw, i.p. once a day) with or without lithium (25 mg/kg bw, i.p. once a day) for 2 weeks. All ACR-administered mice exhibited severe symptoms of neuropathy. We found that treatment with lithium effectively alleviated behavioral deficits in animals elicited by acrylamide. Interestingly, the reduction of hippocampal neurogenesis resulting from ACR injection was promoted by administration of lithium. Further, lithium treatment significantly offset ACR-induced depletion in p-GSK-3β (Ser9) levels in hippocampus. Collectively our findings suggest the propensity of lithium to attenuate ACR-induced neuropathy. Further studies are necessary to understand the precise molecular mechanism by which the lithium attenuates neuropathy. Nevertheless, our data clearly demonstrate the beneficial effects of lithium on ACR-induced neuropathy in mice and suggest its possible therapeutic application as an adjuvant in the management of other forms of neuropathy in humans. PMID:25146901

  8. Flattening a puckered cyclohexasilane ring by suppression of the pseudo-Jahn-Teller effect.

    PubMed

    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 Si(6)X(12) (X = Cl, Br) molecules that contain D(3d) 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 Si(6)X(12), with the Si(6) ring becoming planar (D(6h)) upon complex formation. The stabilizing role of electrostatic and covalent interactions between positively charged silicon atoms and chlorine atoms of the subject [Si(6)Cl(14)](2-) dianionic complexes is discussed. The reaction of Si(6)Cl(12) with a Lewis base (e.g., Cl(-)) to give planar [Si(6)Cl(14)](2-) dianionic complexes presents an experimental proof that suppression of the PJT effect is an effective strategy in restoring high Si(6) ring symmetry. Additionally, the proposed pathway for the PJT suppression has been proved by the synthesis and characterization of novel compounds containing planar Si(6) ring, namely, [(n)Bu(4)N](2)[Si(6)Cl(12)I(2)], [(n)Bu(4)N](2)[Si(6)Br(14)], and [(n)Bu(4)N](2)[Si(6)Br(12)I(2)]. This work represents the first demonstration that PJT effect suppression is useful in the rational design of materials with novel properties. PMID:21218995

  9. 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

  10. 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.