Electron-irradiation-induced phase transformation in alumina

International Nuclear Information System (INIS)

Chen, C.L.; Arakawa, K.; Lee, J.-G.; Mori, H.

2010-01-01

In this study, electron-irradiation-induced phase transformations between alumina polymorphs were investigated by high-resolution transmission electron microscopy. It was found that the electron-irradiation-induced α → κ' phase transformation occurred in the alumina under 100 keV electron irradiation. It is likely that the knock-on collision between incident electrons and Al 3+ cations is responsible for the occurrence of electron-irradiation-induced phase transformation from α-alumina to κ'-alumina.

Thorax irradiation triggers a local and systemic accumulation of immunosuppressive CD4+ FoxP3+ regulatory T cells

International Nuclear Information System (INIS)

Wirsdörfer, Florian; Cappuccini, Federica; Niazman, Muska; Leve, Simone de; Westendorf, Astrid M; Lüdemann, Lutz; Stuschke, Martin; Jendrossek, Verena

2014-01-01

Lymphocyte infiltration is a common feature of radiation-induced pneumonitis and fibrosis, but their contribution to the pathogenic processes is still unclear. Here, we addressed the impact of thorax irradiation on the T cell compartment with a focus on immunosuppressive regulatory T cells (Treg). C57BL/6 wild type mice (WT) received anesthesia only (sham controls, 0 Gy) or were exposed to a single dose of whole thorax irradiation (15 Gy). Immune cells from lung tissue, spleen, and cervical lymph nodes were collected 10 to 84 days post-irradiation and phenotypically characterized by flow cytometry. Whole thorax irradiation provoked an increased influx of CD3+ T cells at 42 and 84 days post-irradiation. In contrast, local irradiation caused a sustained reduction in CD3+ T cells in peripheral lymphoid tissues. Interestingly, we observed a significant local and systemic increase in the fraction of CD4+ T cells expressing the transcription factor forkhead box P3 (FoxP3), the phenotypic marker for murine Treg, at day 21 post-irradiation. The accumulation of Treg was associated with increased levels of T cells expressing surface proteins characteristic for recruitment and immunosuppressive activity, e.g. CD103, CTLA-4 and CD73. Importantly, Treg isolated at this time point were able to suppress CD4+ effector T cells to a similar extent as Treg isolated from control mice. The response of the adaptive immune system to whole thorax irradiation is characterized by local immunoactivation and systemic immunosuppression. The transient accumulation of immunosuppressive CD4+ FoxP3+ Treg may be required to protect the lung against excessive inflammation-induced tissue damage. Further investigations shall define the mechanisms underlying the accumulation of Treg and their role for the pathogenesis of radiation-induced lung disease

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

International Nuclear Information System (INIS)

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

1982-01-01

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

Localized irradiations, Evaluation through ''comet assay''

International Nuclear Information System (INIS)

Giorgio, M.D.; Taja, M.R.; Nasazzi, N.B.; Bustos, N.; Cavalieri, H.; Bolgiani, A.

2000-01-01

During the last 50 years various radiation accidents involving localized irradiations occurred, resulting mainly from improper handling of sealed sources Co 60 , Cs 137 or Ir 192 at workplaces for industrial gammagraphy. Severe skin reaction may develop at the contact sites. Such inhomogeneous irradiations lead to a differential exposure of lymphocytes in lymphatic tissues or other organs that may recirculate into the peripheral blood producing a mixed irradiated and unirradiated population of lymphocytes. Applying the mathematical models ''Contaminated Poisson'' of Dolphin and Qdr method of Sasaki, a mean dose in the irradiated body area and its size can be estimated from unstable chromosome aberration scoring. This give an indication of the proportion of haemopoietic stem cell compartment involved in the overexposure. There are also different biophysical techniques that can give responses in biological dosimetry. The ''Comet Assay'' (single cell gel electrophoresis) is a sensitive and rapid method for DNA strand break detection in individual cells. The advantages of the technique include: collection of data at the level of individual cell; the need for small numbers of cells per sample; its sensitivity for detecting DNA damage and that virtually any eukaryote cell population is amenable to analysis. The objective of this work is to apply ''Comet Assay'' method to evaluate the effect of radiation on skin and subcutaneous tissues, differentiating irradiated from unirradiated body areas. It could provide a useful tool to estimate the extension and the dose in the irradiated region, contributing with the current techniques. In this first study, we evaluate the alkaline comet assay as a method for detection of DNA radiation induced damage in keratinocytes from primary culture obtained from full thickness skin biopsies of patients requiring grafts. Skin and, particularly, keratinocytes were selected as an appropriate cellular system due to: Skin, the first barrier

Regularity of wound healing in rats irradiated locally with different doses of soft X-rays

International Nuclear Information System (INIS)

Liu Jianzhong; Zhou Yuanguo; Cheng Tianmin; Zhou Ping; Liu Xia; Li Ping

2002-01-01

Objective: To study the regular patter of wound healing in rats irradiated locally with different doses of soft X-rays. Methods: Rats were locally irradiated, and wounded immediately thereafter. Gross observation, histopathology and immunohistochemistry examinations, and image analysis were used to study the wound healing process. Results: The authors found that the delayed time of wound healing induced by soft X-ray irradiation of 0.50, 1.01, 1.96, 3,26, 4.00, 5.21 Gy was 1.6, 4.2, 5.4, 6.6, 8.2 and 9.4 days, respectively. Irradiation with 7.0 and 10.0 Gy caused failure of wound healing (up to 40 days). Compared to the non-irradiated wounds, the healing rates of irradiation-impaired wounds were lower during the whole healing process. From day 3 to day 9 after irradiation, the healing rates decreased along with increasing of the radiation dose, indicating the key phase of wound healing was delayed. After irradiation, the collagen synthesis was decreased, its arrangement was disordered, and the structure of granulation tissue was irregular. Conclusion: Soft X-rays irradiation may cause a delay of wound healing in a dose-dependent manner, and irradiation with 7.0 and 10.0 Gy cause failure of wound healing

Physiologic consequences of local heart irradiation in rats

International Nuclear Information System (INIS)

Geist, B.J.; Lauk, S.; Bornhausen, M.; Trott, K.R.

1990-01-01

Noninvasive methods have been used to study the long-term cardiovascular and pulmonary functional changes at rest and after exercise in adult rats following local heart irradiation with single x-ray doses of 15, 17.5 or 20 Gy, and in non-irradiated control animals. Rats that had undergone a chronic exercise program were compared with untrained cohorts. The earliest dysfunction detected was an increased respiratory rate (f) at 10 weeks after irradiation in the highest dose group. In contrast, both telemetric heart-rate (HR) and rhythm and indirect systolic blood pressure measurements performed at rest only revealed changes starting at 43 weeks after irradiation with 20 Gy, up to which point the rats showed no clinical signs of heart failure. However, the number of minutes required for the recovery of the HR to pre-exercise levels following the implementation of a standardized exercise challenge was elevated in untrained rats compared with their trained cohorts at 18 weeks after irradiation with 20 Gy. Increases in recovery times were required in the two lowest dose groups, starting at 26 weeks after irradiation. It was concluded that the reserve capacity of the cardiopulmonary system masks functional decrements at rest for many months following local heart irradiation, necessitating the use of techniques which reveal reductions in reserve capacities. Further, the influence of local irradiation to the heart and lungs deserves closer scrutiny due to mutual interactions

Local graft irradiation in renal transplant rejection

International Nuclear Information System (INIS)

Kawamura, Masashi; Kataoka, Masaaki; Itoh, Hisao

1990-01-01

From 1977 to 1988, of 142 renal transplantations, seven recipients (4.9%) received local graft irradiation following rejective reaction refractory to antirejection medical managements. Concurrent with the administration of pulsed high dose methylprednisolone and other antirejection medical managements, the graft was irradiated with a total dose of 6.0 Gy-150 cGy per fraction every other day at the midplane of the graft using two opposing portals of 4MX Linac. The fields were defined by palpation and echography. All patients had improvements in serum creatinine on the 10th day after beginning the irradiation. Four patients with peripheral lymphocytosis during the irradiation combined with pulsed high dose methylprednisolone improved in renal functions. On the other hand, out of 3 patients with lymphcytopenic changes, in two the transplanted graft was removed due to deteriorations, and the other patient is currently suffering from chronic rejection. Local graft irradiation can be useful in maintaining a rejective graft and reversing its functions in some patients whose rejective reaction failed to respond to the antirejection medical managements. (author)

A case of irradiation-induced malignant fibrous histiocytoma after an operation for rectal cancer

International Nuclear Information System (INIS)

Tahara, Hiroyuki; Kuroda, Yoshinori; Kuranishi, Fumito; Toyota, Kazuhiro; Nakahara Masahiro

2004-01-01

We recently observed a case of presumed irradiation-induced malignant fibrous histiocytoma (MFH), which developed 11 years after postoperative chemoradiotherapy for residual rectal cancer. A 65-year-old female underwent chemoradiotherapy for the residual tumor on the sacrum after abdominoperineal resection for rectal cancer in 1991. She showed no evidence of local recurrence or distant metastasis. Biopsy and MRI in 2002 suggested a retroperitoneal malignant tumor associated with invasion of the uterus and the sacrum, and the patient subsequently underwent surgery. Histopathologically the tumor was MFH. This case was considered to be an irradiation-induced secondary malignant tumor, according to the criteria developed by Arlen et al. In elderly patients and cases that underwent chemoradiotherapy, the latency period of irradiation-induced secondary malignant tumor tends to be shorter. If the progress of postoperative adjuvant chemotherapy increases the number of long-term surviving cases in the future, the incidence of irradiation-induced secondary malignant tumor will increase. It is therefore necessary to survey these cases over a longer period of time after surgery. (author)

Structural and optical properties improvements of PVP/gelatin blends induced by neutron irradiation

Science.gov (United States)

Basha, Mohammad Ahmad-Fouad; Hassan, Mohamed Ahmed

2018-05-01

Blends of polyvinylpyrrolidone and gelatin were prepared in three different concentrations to study the modifications in their structural and optical properties induced by neutron irradiations with different neutron fluence values from 108 up to 1011 neutron/cm2. X-ray spectroscopy revealed that the irradiation has induced a recrystallization phenomenon in the studied blends and the crystallinity index increased by increasing the neutron fluence due to the breaking of the crystallites. Fourier-transform infrared spectroscopy came to confirm the existence of interactions between interchain groups and a higher compatibility for the irradiated blends. The irradiation induced defects inside the material were responsible for the change in their optical and structural properties. The creation of free radicals or ions inside the conduction bands has led to the increase in the number of carriers on localized states; this has caused the increase in optical conductivity of the irradiated blends as a result of decreasing the energy gaps by increasing the neutron fluence. Results may widen the applications of the gelatin based blends to include optoelectronic devices, organic light emitting devices, solar selective and anti-reflectance bio-coatings, optical organic glass and lenses.

Irradiation induced effects in zirconium (A review)

International Nuclear Information System (INIS)

Madden, P.K.

1975-06-01

Irradiation creep in zirconium and its alloys is comprehensively discussed. The main theories are outlined and the gaps between them and the observed creep behaviour, indicated. Although irradiation induced point defects play an important role, effects due to irradiation induced dislocation loops seem insignificant. The experimental results suggest that microstructural variations due to prior cold-working or hydrogen injection perturb the irradiation growth and the irradiation creep of zircaloy. Further investigations into these areas are required. One disadvantage of creep experiments lies in their duration. The possibility of accelerated experiments using ion implantation or electron irradiation is examined in the final section, and its possible advantages and disadvantages are outlined. (author)

Vitamin E-deficiency did not exacerbate partial skin reactions in mice locally irradiated with X-rays

International Nuclear Information System (INIS)

Chi, C.; Hayashi, Daisuke; Nemoto, Masato; Nyui, Minako; Anzai, Kazunori; Urano, Shiro

2011-01-01

We previously showed that free radicals and oxidative stress are involved in radiation-induced skin reactions. Since vitamin E (VE) is a particularly important lipophilic antioxidant, VE-deficient mice were used to examine its effects on radiation-induced skin damage. The VE content of the skin was reduced to one fourth of levels of normal mice. Neither the time of onset nor the extent of the reactions quantified with a scoring system differed between normal and VE-deficient mice after local X-irradiation (50 Gy). Similarly, there was no difference in the levels of the ascorbyl radical between the groups, although they were higher in irradiated skin than non-irradiated skin. X-irradiation increased the amount of Bax protein in the skin of normal mice both in the latent and acute inflammatory stages, time- and dose-dependently. The increase was associated with an increase in cytochrome c in the cytosolic fraction, indicating that apoptosis was also promoted by the irradiation. The increase in Bax protein correlated well with the thickness of the skin. Although a deficiency in VE should lower resistance to free radicals in the mitochondrial membrane and thus enhance radiation-induced Bax expression and apoptosis, it actually attenuated the increase in Bax protein caused by irradiation. (author)

Irradiation hardening and localized deformation of neutron-irradiated α-iron single crystals

International Nuclear Information System (INIS)

Mughrabi, H.; Stroehle, D.; Wilkens, M.

1981-01-01

The early yielding behaviour of neutron-irradiated α iron single crystals orientated for single slip was investigated as a function of neutron dose. In the range of neutron doses between approx. equal to 10 18 and approx. equal to 10 19 n/cm 2 , the irradiation hardening increment was found to be almost constant. Qualitative modifications of this behaviour were observed in the case of predeformed specimens. The localized deformation of the neutron-irradiated specimens by dislocation channelling was investigated by slip-line observations, transmission electron microscopy and X-ray topography. A model of localized deformation is proposed in order to explain the development of the observed asymmetric dislocation double layers which bound the channels and transmit characteristic misorientations. (orig.)

Effects of X-irradiation on axonal sprouting induced by botulinum toxin

Energy Technology Data Exchange (ETDEWEB)

Gomez, S; Duchen, L W [National Hospital, London (UK); Hornsey, S [Hammersmith Hospital, London (UK). M.R.C. Cyclotron Unit

1982-01-01

The effect of X-irradiation on axonal sprouting of motor nerves induced by botulinum toxin was examined. Muscles of one leg in the mouse were X-irradiated (15Gy) prior to the injection of a locally paralysing dose of botulinum toxin. It was found that axonal sprouting occurred as expected, but the sprouts remained unmyelinated and many degenerated. Fewer new end-plates were formed, muscles remained more severely atrophied and supersensitive to acetylcholine and recovery of neuromuscular transmission was greatly delayed when compared with the effects of botulinum toxin alone. X-irradiation did not prevent sprouting but, probably by impairing Schwann cell proliferation, altered axon-Schwann cell relationships and prevented the maturation of newly-formed axons and the differentiation of new end-plates.

Free radicals induced archive paper by irradiation

International Nuclear Information System (INIS)

Cutrubinis, M.; Moise, I.V.; Negut, C.D.; Georgescu, R.; Suvaila, R.; Virgolici, M.; Manea, M.M.

2011-01-01

Complete text of publication follows. Irradiation of archive paper (document archives of institutions, companies etc. and library or museum collections of books and documents) can solve the problems related to the bio-deterioration and bio-contamination of paper and sometimes save valuable cultural heritage paper items. For valuable paper items care should be taken to the degradation induced instantly by the ionising radiation to the cellulosic support and also to the long term post-irradiation effects. The free radicals formed due to the irradiation treatment could contribute to instant degradation of paper. Part of them are also trapped for months and years after irradiation and they could be related to the post-irradiation effects in paper items. In this study, different sorts of cellulosic support samples (soft wood and hard wood cellulose, contemporary paper, paper from archives and from collections etc.) have been irradiated with dosis up to 100 kGy and the radiation induced free radicals have been measured by ESR spectrometry. The ESR signals have shown the type and quantity of radiation induced free radicals. Their study can be used for a realistic estimation of the degradative effect of the ionising radiation treatment of archive paper.

Mutation induced with ion beam irradiation in rose

Energy Technology Data Exchange (ETDEWEB)

Yamaguchi, H. E-mail: yhiroya@nias.affrc.go.jp; Nagatomi, S.; Morishita, T.; Degi, K.; Tanaka, A.; Shikazono, N.; Hase, Y

2003-05-01

The effects of mutation induction by ion beam irradiation on axillary buds in rose were investigated. Axillary buds were irradiated with carbon and helium ion beams, and the solid mutants emerged after irradiation by repeated cutting back. In helium ion irradiation, mutations were observed in plants derived from 9 buds among 56 irradiated buds in 'Orange Rosamini' and in plants derived from 10 buds among 61 irradiated buds in 'Red Minimo'. In carbon ion, mutations were observed in plants derived from 12 buds among 88 irradiated buds in 'Orange Rosamini'. Mutations were induced not only in higher doses but also in lower doses, with which physiological effect by irradiation was hardly observed. Irradiation with both ion beams induced mutants in the number of petals, in flower size, in flower shape and in flower color in each cultivar.

Ion irradiation-induced swelling and hardening effect of Hastelloy N alloy

Energy Technology Data Exchange (ETDEWEB)

Zhang, S.J. [Key Laboratory of Artificial Micro-and Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Li, D.H.; Chen, H.C.; Lei, G.H.; Huang, H.F.; Zhang, W.; Wang, C.B. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Yan, L., E-mail: yanlong@sinap.ac.cn [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Fu, D.J. [Key Laboratory of Artificial Micro-and Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Tang, M. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

2017-06-15

The volumetric swelling and hardening effect of irradiated Hastelloy N alloy were investigated in this paper. 7 MeV and 1 MeV Xe ions irradiations were performed at room temperature (RT) with irradiation dose ranging from 0.5 to 27 dpa. The volumetric swelling increases with increasing irradiation dose, and reaches up to 3.2% at 27 dpa. And the irradiation induced lattice expansion is also observed. The irradiation induced hardening initiates at low ion dose (≤1dpa) then saturates with higher ion dose. The irradiation induced volumetric swelling may be ascribed to excess atomic volume of defects. The irradiation induced hardening may be explained by the pinning effect where the defects can act as obstacles for the free movement of dislocation lines. And the evolution of the defects' size and number density could be responsible for the saturation of hardness. - Highlights: •Irradiation Swelling: The irradiation induced volumetric swelling increases with ion dose. •Irradiation Hardening: The irradiation hardening initiates below 1 dpa, then saturates with higher ion dose (1–10 dpa). •Irradiation Mechanism: The irradiation phenomena are ascribed to the microstructural evolution of the irradiation defects.

Irradiation creep due to SIPA-induced growth

International Nuclear Information System (INIS)

Woo, C.H.

1980-01-01

An additional contribution to irradiation creep resulting from the stress-induced preferred adsorption (SIPA) effect is described - SIPA-induced growth (SIG). The mechanism of SIG is discussed and an expression for its contribution to irradiation creep developed. It is shown that SIG is very significant in comparison with SIPA. Enhancement of creep by swelling may also occur. (U.K.)

Irradiation-induced doping of Bismuth Telluride Bi2Te3

International Nuclear Information System (INIS)

Rischau, Carl Willem

2014-01-01

around the point of optimal compensation. This coexistence is explained by the formation of charge puddles due to spatial inhomogeneities in the distribution of defects and the associated charges. Moreover, it was shown that at both temperatures, the irradiation-induced defects lead to a strong decrease of the hole carrier concentration and the electron mobility so that a metal-insulator transition in terms of the Ioffe-Regel criterion can be achieved. However, the irradiation-induced changes of the carrier concentration are not sufficient to induce a Mott metal-insulator transition. The magnetoresistance measured in-situ during low temperature irradiation shows the presence of weak anti-localization, which might be a signature of the topologically protected surface states. (author)

Irradiation induced precipitation in tungsten based, W-Re alloys

Science.gov (United States)

Williams, R. K.; Wiffen, F. W.; Bentley, J.; Stiegler, J. O.

1983-03-01

Tungsten-base alloys containing 5, 11, and 25 pct Re were irradiated in the EBR-II reactor. Irradiation temperatures ranged from 600 to 1500 °C. All compositions were irradiated to fluences in the range 4.3 to 6.1 X 1025 n/m2 (E > 0.1 MeV), and three 25 pct Re samples were also irradiated to 3.7 X 1026 n/m2 at temperatures 700 to 900 °C. Postirradiation examination included measurement of electrical resistivity at room temperature and lower temperatures, X-ray diffraction, optical metallography, microprobe analysis, and transmission electron microscopy. Irradiation induced resistivity decreases observed in most of the samples suggested second-phase precipitation. Complete results confirmed the precipitate formation in all samples, in disagreement with existing phase diagrams for the W-Re system. Electron diffraction showed the precipitates to be consistent with the cubic, Re-rich X-phase and inconsistent with the σ-phase. Large variations in precipitate morphology and distribution were observed between the different compositions and irradiation conditions. For the 5 and 11 pct Re-alloys, spherically symmetric strain fields surrounded the equiaxed precipitate particles, and were observed even where no particles were visible. These strain fields are believed to arise from local Re enrichment. Thermoelectric data show that the precipitation can lead to decalibration of W/Re thermocouples.

Histological and elemental changes in the rat brain after local irradiation with carbon ion beams

Energy Technology Data Exchange (ETDEWEB)

Takahashi, Sentaro; Sun, Xue-Zhi; Kubota, Yoshihisa; Takai, Nobuhiko; Nojima, Kumie [National Inst. of Radiological Sciences, Chiba (Japan)

2002-06-01

The left cerebral hemispheres of adult Sprague-Dawley rat brains were irradiated at doses of 30, 50, or 100 Gy with charged carbon particles (290 MeV/nucleon; 5 mm spread-out Bragg peak). The spread-out Bragg peak used here successfully and satisfactorily retained its high-dose localization in the defined region. A histological examination showed that necrotic tissue damage, hemorrhage in the thalamus, and vasodilatations around the necrotic region were induced at 8 weeks after 100 Gy irradiation. The regions with tissue damage correlated well with those expected from the radiation-dose distribution, indicating an advantage of charged carbon particles for irradiating restricted brain regions. An X-ray fluorescent analysis demonstrated a decrease in the concentrations of K and P, and an increase in the concentrations of Cl, Fe, Zn in the damaged region at 8 weeks post-irradiation, though no significant changes were observed before 4 weeks of post-irradiation. This may indicate that even the very high radiation doses used here did not induce acute and immediate neuronal cell death, in contrast with ischemic brain injury where acute neuronal cell death occurred and the elemental concentrations changed within a day after the induction of ischemia. (author)

Analysis of radicals induced in irradiated foods

International Nuclear Information System (INIS)

Kishida, Keigo; Kaimori, Yoshihiko; Kawamura, Shoei; Sakamoto, Yuhki; Nakamura, Hideo; Ukai, Mitsuko; Kikuchi, Masahiro; Shimoyama, Yuhei; Kobayashi, Yasuhiko

2012-01-01

By electron spin resonance (ESR) spectroscopy, we revealed free radicals in γ-ray irradiated foods; black pepper, green coffee bean and ginseng. We also analyzed the decay behavior of radiation induced free radicals during storage of irradiated foods. The ESR spectrum of experimental irradiated foods consists of a sextet signal centered at g=2.0 and a singlet signal at the same g-value position and a singlet signal at g=4.0. The singlet signal at g=2.0 is originated from organic free radicals and its peak intensity showed the dependence of γ-ray irradiation dose levels. The signal intensity was decreased during storage. Only after 3 hours of radiation treatment the peak intensity was decreased fast and after that the intensity was decreased slowly. The relaxation times, T 1 and T 2 , of radiation induced free radicals showed the variations before and after irradiation. During long time storage period it was shown that T 1 was increased and T 2 was decreased. By analysis of decay process using the simulation methods based on the theory of reaction speed, it is considered that at least two kinds of radicals were induced in irradiated foods during long time storage. (author)

Intraoperative irradiation for locally recurrent colorectal cancer in previously irradiated patients

International Nuclear Information System (INIS)

Haddock, Michael G.; Gunderson, Leonard L.; Nelson, Heidi; Cha, Stephen S.; Devine, Richard M.; Dozois, Roger R.; Wolff, Bruce G.

2001-01-01

Purpose: Information in the literature regarding salvage treatment for patients with locally recurrent colorectal cancer who have previously been treated with high or moderate dose external beam irradiation (EBRT) is scarce. A retrospective review was therefore performed in our institution to determine disease control, survival, and tolerance in patients treated aggressively with surgical resection and intraoperative electron irradiation (IOERT) ± additional EBRT and chemotherapy. Methods and Materials: From 1981 through 1994, 51 previously irradiated patients with recurrent locally advanced colorectal cancer without evidence of distant metastatic disease were treated at Mayo Clinic Rochester with surgical resection and IOERT ± additional EBRT. An attempt was made to achieve a gross total resection before IOERT if it could be safely accomplished. The median IOERT dose was 20 Gy (range, 10-30 Gy). Thirty-seven patients received additional EBRT either pre- or postoperatively with doses ranging from 5 to 50.4 Gy (median 25.2 Gy). Twenty patients received 5-fluorouracil ± leucovorin during EBRT. Three patients received additional cycles of 5-fluorouracil ± leucovorin as maintenance chemotherapy. Results: Thirty males and 21 females with a median age of 55 years (range 31-73 years) were treated. Thirty-four patients have died; the median follow-up in surviving patients is 21 months. The median, 2-yr, and 5-yr actuarial overall survivals are 23 months, 48% and 12%, respectively. The 2-yr actuarial central control (within IOERT field) is 72%. Local control at 2 years has been maintained in 60% of patients. There is a trend toward improved local control in patients who received ≥30 Gy EBRT in addition to IOERT as compared to those who received no EBRT or <30 Gy with 2-yr local control rates of 81% vs. 54%. Distant metastatic disease has developed in 25 patients, and the actuarial rate of distant progression at 2 and 4 years is 56% and 76%, respectively. Peripheral

Electron irradiation-induced defects in {beta}-SiC

Energy Technology Data Exchange (ETDEWEB)

Oshima, Ryuichiro [Osaka Prefectural Univ., Sakai (Japan). Reseach Inst. for Advanced Science and Technology

1996-04-01

To add information of point defects in cubic crystal SiC, polycrystal {beta}-SiC on the market was used as sample and irradiated by neutron and electron. In situ observation of neutron and electron irradiation-induced defects in {beta}-SiC were carried out by ultra high-voltage electronic microscope (UHVEM) and ordinary electronic microscope. The obtained results show that the electron irradiation-induced secondary defects are micro defects less than 20 nm at about 1273K, the density of defects is from 2x10{sup 17} to 1x10{sup 18}/cc, the secondary defects may be hole type at high temperature and the preexistant defects control nuclear formation of irradiation-induced defects, effective sink. (S.Y.)

Irradiation-enhanced and-induced mass transport

International Nuclear Information System (INIS)

Rehn, L.E.

1989-01-01

Irradiation can be used to enhance diffusion, that is, to increase the rate at which equilibrium is attained, as well as to induce nonequilibrium changes. The main factors influencing whether irradiation will drive a material toward or away from equilibrium are the initial specimen microstructure and geometry, irradiation temperature, and primary recoil spectrum. This paper summarizes known effects of irradiation temperature and primary recoil spectrum on mass transport during irradiation. In comparison to either electron or heavy-ion irradiation, it is concluded that relatively low-energy, light-ion bombardment at intermediate temperatures offers the greatest potential to enhance the rate at which equilibrium is attained. The greatest departures from equilibrium can be expected from irradiation with similar particles at very low temperatures

Hemibody irradiation

International Nuclear Information System (INIS)

Schen, B.C.; Mella, O.; Dahl, O.

1992-01-01

In a large number of cancer patients, extensive skeletal metastases or myelomatosis induce vast suffering, such as intolerable pain and local complications of neoplastic bone destruction. Analgetic drugs frequently do not yield sufficient palliation. Irradiation of local fields often has to be repeated, because of tumour growth outside previously irradiated volumes. Wide field irradiation of the lower or upper half of the body causes significant relief of pain in most patients. Adequate pretreatment handling of patients, method of irradiation, and follow-up are of importance to reduce side effects, and are described as they are carried out at the Department of Oncology, Haukeland Hospital, Norway. 16 refs., 2 figs

Spontaneous and x-irradiation induced carcinomas of small intestine in Wistar-Furth rats

Energy Technology Data Exchange (ETDEWEB)

Maeura, Y; Kosaki, G; Kitamura, H [Osaka Univ. (Japan). Faculty of Medicine; Nagatomo, T

1980-04-01

Spontaneous carcinoma of the small intestine in Wistar-Furth (WF) rats and carcinoma of the small intestine induced by local x-ray irradiation to the abdomen of WF rats without carcinoma were observed, and x-ray sensitivity of the small intestine mucosa was reported. Out of 19 rats with spontaneous carcinoma of the small intestine, 18 also had carcinoma of the colon, and 4 also had gastric cancer. They already had spontaneous carcinoma of the small intestine within 2 weeks after their birth, and the ratio of female and male was 13 : 6. Histological type of this carcinoma in all 19 rats was highly differentiated adenocarcinoma, and small intestine epithelium around carcinoma presented atypical epithelium. As to mice without carcinoma, x-ray, 1,000 R, 1,500 R, and 2,000 R, was irradiated to the abdomen of Sprague-Dawley (SD) and WF rats. In the irradiation with 1,000 R, carcinogenesis was not found in rats of both strains. In the irradiation with 1,500 R, carcinogenesis was hardly found, but in the irradiation with 2,000 R, carcinoma of small intestine occurred in 5 of 17 rats 15 weeks after the irradiation, 9 of 19 rats 25 weeks after the irradiation, and 9 of 14 rats 35 weeks after the irradiation. Histological type of carcinoma in irradiated rats was highly differentiated adenocarcinoma. The incidence of carcinoma in irradiated rats was higher in WF rats than SD rats through the course after the irradiation, which suggested that x-ray sensitivity of WF rats was higher than that of SD rats. Therefore, carcinoma of the small intestine in irradiated mice seemed to be induced by x-ray.

Time distributions of recurrences of immunogenic and nonimmunogenic tumors following local irradiation

International Nuclear Information System (INIS)

Suit, H.D.; Sedlacek, R.; Fagundes, L.; Goitein, M.; Rothman, K.J.

1978-01-01

Three hundred and fourteen mice received single-dose irradiation of the right leg and thigh as treatment of an 8-mm mammary carcinoma isotransplant, and were then observed until death, usually by 1000 days. The time distributions of death due to local recurrence, radiation-induced sarcoma, distant metastasis in the absence of local regrowth, second primary, intercurrent disease, and unknown causes have been evaluated. The times for the transplant tumor inoculum to grow to an 8-mm tumor and the times of death due to local regrowth, distant metastasis, or induced tumor were all approximately log-normally distributed. Of the 128 recurrences, the latest-appearing 3 were at 300, 323, and 436 days; no recurrences were noted during the time period from 436 to 1000 days. These findings have been interpreted to mean that in some cases absolute cure of mice of the tumor in the leg was achieved by radiation alone at the dose levels employed. Radiation-induced sarcomas began to appear after 300 days. The time of appearance of the radiation-induced tumors was inversely related to radiation dose. Similar data for an immunogenic fibrosarcoma show that recurrences appeared earlier and were more closely bunched with respect to time than the recurrences of mammary carcinoma. The time distribution of the development of radiation-induced tumors in non-tumor-bearing animals was also approximately long-normally distributed; the slope of the time distribution curve was the same as that for radiation-induced tumors in mice which had been treated for tumor

Re-irradiation after salvage mastectomy for local recurrence after a conservative treatment: a retrospective analysis of twenty patients (Nancy: 1988-2001)

International Nuclear Information System (INIS)

Racadot, S.; Marchal, C.; Charra-Brunaud, C.; Peiffert, D.; Bey, P.; Verhaeghe, J.L.

2003-01-01

Purpose. - To retrospectively assess the efficacy of post-mastectomy re-irradiation for local relapse of breast cancer. Patients and methods. - Twenty patients, initially treated by conservative surgery and radiotherapy (50 Gy in 25 fractions over 5 weeks) were treated from 1998 to 2001 for a local relapse by salvage mastectomy and re-irradiation (either electron or photon beams). Mean age was 53 years (31-71). Reasons for re-irradiation were that the local relapses were inflammatory (4 pts), multifocal (5 pts), cutaneous (5 pts), involved the nipple (3 pts) or because the surgical margins (either muscle or skin) were involved (3 pts). The median dose of re-irradiation was 45 Gy (33-65) in 15 fractions over 33 days. Mean follow-up was 48 months (5-97). Results. - Fifteen patients remained free of a second local recurrence and 10 were still alive, without metastasis. Neither the dose of re-irradiation nor the irradiated surfaces were prognostic factors of local control (P = 0.877 and P = 0.424). Five patients developed radiation-induced pneumonitis without functional respiratory impairment. The incidence of pneumonitis seemed to be related to the biological dose of re-irradiation (P = 0.037). Other late complications occurred such as pigmentation changes (12 pts), telangiectasia (8 pts), chondritis (2 pts), parietal fibrosis (7 pts), rib fractures (4 pts), severe pain (11 pts) and lymphedema (2 pts). The increase in biological equivalent dose was highly statistically linked with the occurrence of disabling pain (P = 0.0123). Conclusion. - Parietal re-irradiation achieves good and lasting local control with an acceptable rate of acute complications but with a risk of disabling late sequelae such as severe pain. (author)

Localized surface grafting reactions on carbon nanofibers induced by gamma and e-beam irradiation

Energy Technology Data Exchange (ETDEWEB)

Evora, M.C., E-mail: cecilia@ieav.cta.br [Institute for Advanced Studies-IEAV/DCTA, Av. Cel Jose Alberto Albano do Amarante, 1-Putim, 12228-001 São Jose dos Campos, SP (Brazil); Araujo, J.R., E-mail: jraraujo@inmetro.gov.br [Instituto Nacional de Metrologia, Qualidade e Tecnologia, Av. Nossa Sra. das Graças, 50, 25250-020 Duque de Caxias, RJ (Brazil); Ferreira, E.H.M. [Instituto Nacional de Metrologia, Qualidade e Tecnologia, Av. Nossa Sra. das Graças, 50, 25250-020 Duque de Caxias, RJ (Brazil); Strohmeier, B.R. [Thermo Fisher Scientific, 5225 Verona Road, Madison, WI 53711 (United States); Silva, L.G.A., E-mail: lgasilva@ipen.br [Institute for Nuclear and Energy Research- IPEN, Av. Prof lineu Prestes, 2242- Cidade Universitaria, 05508-000 SP (Brazil); Achete, C.A. [Instituto Nacional de Metrologia, Qualidade e Tecnologia, Av. Nossa Sra. das Graças, 50, 25250-020 Duque de Caxias, RJ (Brazil)

2015-04-30

Graphical abstract: - Highlights: • Methodology for the functionalization of carbon nanofibers was investigated. • Two radiation sources were used to promote grafting reactions: gamma and electron beam. • We report the optimum inhibitor concentration to achieve the functionalization. • Surface of carbon nanofibers showed an increase of oxygen content after irradiation. • The radiation-induced graphitization did not damage the overall sp{sup 2} structure. - Abstract: Electron beam and gamma-ray irradiation have potential application to modify the carbon fiber nanostructures in order to produce useful defects in the graphitic structure and create reactive sites. In this study, the methodology to functionalize carbon nanofiber (CNF), via a radiation process and using acrylic acid as a source of oxygen functional groups, was investigated. The samples were submitted to a direct grafting radiation process with electron beam and gamma-ray source. Several parameters were changed such as: acrylic acid concentration, radiation dose and percentage of inhibitor necessary to achieve functionalization, with higher percentage of oxygen functional groups on CNF surface, and better dispersion. The better results achieved were when mixing CNF in a solution of acrylic acid with 6% of inhibitor (FeSO{sub 4}·7H{sub 2}O) and irradiated at 100 kGy. The samples were characterized by X-ray photoelectron spectroscopy and the surface composition (atomic%) showed a significant increase of oxygen content for the samples after irradiation. Also, the dispersion of the functionalized CNF in water was stable during months which may be a good indication that the functionalization process of CNF via ionizing radiation was successful.

Localized surface grafting reactions on carbon nanofibers induced by gamma and e-beam irradiation

International Nuclear Information System (INIS)

Evora, M.C.; Araujo, J.R.; Ferreira, E.H.M.; Strohmeier, B.R.; Silva, L.G.A.; Achete, C.A.

2015-01-01

Graphical abstract: - Highlights: • Methodology for the functionalization of carbon nanofibers was investigated. • Two radiation sources were used to promote grafting reactions: gamma and electron beam. • We report the optimum inhibitor concentration to achieve the functionalization. • Surface of carbon nanofibers showed an increase of oxygen content after irradiation. • The radiation-induced graphitization did not damage the overall sp 2 structure. - Abstract: Electron beam and gamma-ray irradiation have potential application to modify the carbon fiber nanostructures in order to produce useful defects in the graphitic structure and create reactive sites. In this study, the methodology to functionalize carbon nanofiber (CNF), via a radiation process and using acrylic acid as a source of oxygen functional groups, was investigated. The samples were submitted to a direct grafting radiation process with electron beam and gamma-ray source. Several parameters were changed such as: acrylic acid concentration, radiation dose and percentage of inhibitor necessary to achieve functionalization, with higher percentage of oxygen functional groups on CNF surface, and better dispersion. The better results achieved were when mixing CNF in a solution of acrylic acid with 6% of inhibitor (FeSO 4 ·7H 2 O) and irradiated at 100 kGy. The samples were characterized by X-ray photoelectron spectroscopy and the surface composition (atomic%) showed a significant increase of oxygen content for the samples after irradiation. Also, the dispersion of the functionalized CNF in water was stable during months which may be a good indication that the functionalization process of CNF via ionizing radiation was successful

Antitumor bystander effect induced by radiation-inducible target gene therapy combined with α particle irradiation

International Nuclear Information System (INIS)

Liu Hui; Jin Chufeng; Wu Yican; Ge Shenfang; Wu Lijun; FDS Team

2012-01-01

In this work, we investigated the bystander effect of the tumor and normal cells surrounding the target region caused by radiation-inducible target gene therapy combined with α-particle irradiation. The receptor tumor cell A549 and normal cell MRC-5 were co-cultured with the donor cells irradiated to 0.5 Gy or the non-irradiated donor cells, and their survival and apoptosis fractions were evaluated. The results showed that the combined treatment of Ad-ET and particle irradiation could induce synergistic antitumor effect on A549 tumor cell, and the survival fraction of receptor cells co-cultured with the irradiated cells decreased by 6%, compared with receptor cells co-cultured with non-irradiated cells, and the apoptosis fraction increased in the same circumstance, but no difference was observed with the normal cells. This study demonstrates that Ad-ET combined with α-particle irradiation can significantly cause the bystander effect on neighboring tumor cells by inhibiting cell growth and inducing apoptosis, without obvious toxicity to normal cells. This suggests that combining radiation-inducible TRAIL gene therapy and irradiation may improve tumor treatment efficacy by specifically targeting tumor cells and even involving the neighboring tumor cells. (authors)

Ion mass dependence of irradiation-induced local creation of ferromagnetism in Fe60Al40 alloys

International Nuclear Information System (INIS)

Fassbender, J.; Liedke, M. O.; Strache, T.; Moeller, W.; Menendez, E.; Sort, J.; Rao, K. V.; Deevi, S. C.; Nogues, J.

2008-01-01

Ion irradiation of Fe 60 Al 40 alloys results in the phase transformation from the paramagnetic, chemically ordered B2 phase to the ferromagnetic, chemically disordered A2 phase. The magnetic phase transformation is related to the number of displacements per atom (dpa) during the irradiation. For heavy ions (Ar + , Kr + , and Xe + ), a universal curve is observed with a steep increase in the fraction of the ferromagnetic phase that reaches saturation, i.e., a complete phase transformation, at about 0.5 dpa. This proves the purely ballistic nature of the disordering process. If light ions are used (He + and Ne + ), a pronounced deviation from the universal curve is observed. This is attributed to bulk vacancy diffusion from the dilute collision cascades, which leads to a partial recovery of the thermodynamically favored B2 phase. Comparing different noble gas ion irradiation experiments allows us to assess the corresponding counteracting contributions. In addition, the potential to create local ferromagnetic areas embedded in a paramagnetic matrix is demonstrated

Mechanisms involved in the differential recovery of CD4 and CD8 T-lymphocytes after local irradiation in mice

International Nuclear Information System (INIS)

De Ruysscher, D; Waer, M.; Vandeputte, M.; Van der Schueren, E.

1990-01-01

The mechanisms involved in the differential recovery of CD4 (helper/inducer phenotype) and CD8 (Cytotoxic/suppressor phenotype) T-lymphocytes after fractionated local irradiation were investigated. In mice, a better recovery of CD4 cells than of CD8 cells was found, while the reverse has been described in humans. Differences in radiosensivitity between CD4 and CD8 mouse splenocytes could not be found. No sequestration of CD8 cells in irradiated tissues could be demonstrated. Irradiation of the thymus did not influence the observed immune changes. Altered thymic production of CD4 and CD8 cells could be excluded by intrathymic injection of FITC (fluorescein isothiocyanate). Hindlimb and tail irradiation did suggest that the differential recovery of CD4 and CD8 T-lymphocytes after local irradiation is determined by extrathymic factors in man and mice, and that the observed differences in immune recovery between man and mice are due to defective thymic function in the former and normal function in the latter. (author). 12 refs.; 5 figs.; 2 tabs

Irradiation-induced amorphization process in graphite

Energy Technology Data Exchange (ETDEWEB)

Abe, Hiroaki [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

1996-04-01

Effects of the element process of irradiation damage on irradiation-induced amorphization processes of graphite was studied. High orientation thermal decomposed graphite was cut about 100 nm width and used as samples. The irradiation experiments are carried out under the conditions of electronic energy of 100-400 KeV, ion energy of 200-600 KeV, ionic species Xe, Ar, Ne, C and He and the irradiation temperature at from room temperature to 900 K. The critical dose ({phi}a) increases exponentially with increasing irradiation temperature. The displacement threshold energy of graphite on c-axis direction was 27 eV and {phi}a{sup e} = 0.5 dpa. dpa is the average number of displacement to atom. The critical dose of ion irradiation ({phi}a{sup i}) was 0.2 dpa at room temperature, and amorphous graphite was produced by less than half of dose of electronic irradiation. Amorphization of graphite depending upon temperature is discussed. (S.Y.)

Origins of ion irradiation-induced Ga nanoparticle motion on GaAs surfaces

International Nuclear Information System (INIS)

Kang, M.; Wu, J. H.; Chen, H. Y.; Thornton, K.; Goldman, R. S.; Sofferman, D. L.; Beskin, I.

2013-01-01

We have examined the origins of ion irradiation-induced nanoparticle (NP) motion. Focused-ion-beam irradiation of GaAs surfaces induces random walks of Ga NPs, which are biased in the direction opposite to that of ion beam scanning. Although the instantaneous NP velocities are constant, the NP drift velocities are dependent on the off-normal irradiation angle, likely due to a difference in surface non-stoichiometry induced by the irradiation angle dependence of the sputtering yield. It is hypothesized that the random walks are initiated by ion irradiation-induced thermal fluctuations, with biasing driven by anisotropic mass transport

Sub-micron indent induced plastic deformation in copper and irradiated steel

International Nuclear Information System (INIS)

Robertson, Ch.

1998-09-01

In this work we aim to study the indent induced plastic deformation. For this purpose, we have developed a new approach, whereby the indentation curves provides the mechanical behaviour, while the deformation mechanisms are observed thanks to Transmission Electron Microscopy (TEM). In order to better understand how an indent induced dislocation microstructure forms, numerical modeling of the indentation process at the scale of discrete dislocations has been worked out as well. Validation of this modeling has been performed through direct comparison of the computed microstructures with TEM micrographs of actual indents in pure Cu [001]. Irradiation induced modifications of mechanical behaviour of ion irradiated 316L have been investigated, thanks to the mentioned approach. An important hardening effect was reported from indentation data (about 50%), on helium irradiated 316L steel. TEM observations of the damage zone clearly show that this behaviour is associated with the presence of He bubbles. TEM observations of the indent induced plastic zone also showed that the extent of the plastic zone is strongly correlated with hardness, that is to say: harder materials gets a smaller plastic zone. These results thus clearly established that the selected procedure can reveal any irradiation induced hardening in sub-micron thick ion irradiated layers. The behaviour of krypton irradiated 316L steel is somewhat more puzzling. In one hand indeed, a strong correlation between the defect cluster size and densities on the irradiation temperature is observed in the 350 deg C -600 deg C range, thanks to TEM observations of the damage zone. On the other hand, irradiation induced hardening reported from indentation data is relatively small (about 10%) and shows no dependence upon the irradiation temperature (within the mentioned range). In addition, it has been shown that the reported hardening vanishes following appropriate post-irradiation annealing, although most of the TEM

Solar-simulated ultraviolet irradiation induces selective influx of CD4+ T lymphocytes in normal human skin

NARCIS (Netherlands)

Di Nuzzo, S.; de Rie, M. A.; van der Loos, C. M.; Bos, J. D.; Teunissen, M. B.

1996-01-01

The proportion and composition of the human cutaneous CD3+ T lymphocyte population was determined in situ following a single exposure to physiological, erythema-inducing doses of simulated solar radiation, mainly consisting of UV radiation. Biopsies were taken 1, 2 and 7 days after local irradiation

Irradiation induced surface segregation in concentrated alloys: a contribution

International Nuclear Information System (INIS)

Grandjean, Y.

1996-01-01

A new computer modelization of irradiation induced surface segregation is presented together with some experimental determinations in binary and ternary alloys. The model we propose handles the alloy thermodynamics and kinetics at the same level of sophistication. Diffusion is described at the atomistic level and proceeds vis the jumps of point defects (vacancies, dumb-bell interstitials): the various jump frequencies depend on the local composition in a manner consistent with the thermodynamics of the alloy. For application to specific alloys, we have chosen the simplest statistical approximation: pair interactions in the Bragg Williams approximation. For a system which exhibits the thermodynamics and kinetics features of Ni-Cu alloys, the model generates the behaviour parameters (flux and temperature) and of alloy composition. Quantitative agreement with the published experimental results (two compositions, three temperatures) is obtained with a single set of parameters. Modelling austenitic steels used in nuclear industry requires taking into account the contribution of dumbbells to mass transport. The effects of this latter contribution are studied on a model of Ni-Fe. Interstitial trapping on dilute impurities is shown to delay or even suppress the irradiation induced segregation. Such an effect is indeed observed in the experiments we report on Fe 50 Ni 50 and Fe 49 Ni 50 Hf 1 alloys. (author)

Experiment-based modelling of hardening and localized plasticity in metals irradiated under cascade damage conditions

International Nuclear Information System (INIS)

Singh, B.N.; Ghoniem, N.M.; Trinkaus, H.

2002-01-01

The analysis of the available experimental observations shows that the occurrence of a sudden yield drop and the associated plastic flow localization are the major concerns regarding the performance and lifetime of materials exposed to fission or fusion neutrons. In the light of the known mechanical properties and microstructures of the as-irradiated and irradiated and deformed materials, it has been argued that the increase in the upper yield stress, the sudden yield drop and the initiation of plastic flow localization, can be rationalized in terms of the cascade induced source hardening (CISH) model. Various aspects of the model (main assumptions and predictions) have been investigated using analytical calculations, 3-D dislocation dynamics and molecular dynamics simulations. The main results and conclusions are briefly summarized. Finally, it is pointed out that even though the formation of cleared channels may be rationalized in terms of climb-controlled glide of the source dislocation, a number of problems regarding the initiation and the evolution of these channels remain unsolved

Experiment-based modelling of hardening and localized plasticity in metals irradiated under cascade damage conditions

Energy Technology Data Exchange (ETDEWEB)

Singh, B.N. E-mail: bachu.singh@risoe.dk; Ghoniem, N.M.; Trinkaus, H

2002-12-01

The analysis of the available experimental observations shows that the occurrence of a sudden yield drop and the associated plastic flow localization are the major concerns regarding the performance and lifetime of materials exposed to fission or fusion neutrons. In the light of the known mechanical properties and microstructures of the as-irradiated and irradiated and deformed materials, it has been argued that the increase in the upper yield stress, the sudden yield drop and the initiation of plastic flow localization, can be rationalized in terms of the cascade induced source hardening (CISH) model. Various aspects of the model (main assumptions and predictions) have been investigated using analytical calculations, 3-D dislocation dynamics and molecular dynamics simulations. The main results and conclusions are briefly summarized. Finally, it is pointed out that even though the formation of cleared channels may be rationalized in terms of climb-controlled glide of the source dislocation, a number of problems regarding the initiation and the evolution of these channels remain unsolved.

In situ transmission electron microscope studies of ion irradiation-induced and irradiation-enhanced phase changes

International Nuclear Information System (INIS)

Allen, C.W.

1992-01-01

Motivated at least initially by materials needs for nuclear reactor development, extensive irradiation effects studies employing transmission electron microscopes (TEM) have been performed for several decades, involving irradiation-induced and irradiation-enhanced microstructural changes, including phase transformations such as precipitation, dissolution, crystallization, amorphization, and order-disorder phenomena. From the introduction of commercial high voltage electron microscopes (HVEM) in the mid-1960s, studies of electron irradiation effects have constituted a major aspect of HVEM application in materials science. For irradiation effects studies two additional developments have had particularly significant impact; the development of TEM specimen holder sin which specimen temperature can be controlled in the range 10-2200 K and the interfacing of ion accelerators which allows in situ TEM studies of irradiation effects and the ion beam modification of materials within this broad temperature range. This paper treats several aspects of in situ studies of electron and ion beam-induced and enhanced phase changes and presents two case studies involving in situ experiments performed in an HVEM to illustrate the strategies of such an approach of the materials research of irradiation effects

Nitric oxide-mediated bystander signal transduction induced by heavy-ion microbeam irradiation

Science.gov (United States)

Tomita, Masanori; Matsumoto, Hideki; Funayama, Tomoo; Yokota, Yuichiro; Otsuka, Kensuke; Maeda, Munetoshi; Kobayashi, Yasuhiko

2015-07-01

In general, a radiation-induced bystander response is known to be a cellular response induced in non-irradiated cells after receiving bystander signaling factors released from directly irradiated cells within a cell population. Bystander responses induced by high-linear energy transfer (LET) heavy ions at low fluence are an important health problem for astronauts in space. Bystander responses are mediated via physical cell-cell contact, such as gap-junction intercellular communication (GJIC) and/or diffusive factors released into the medium in cell culture conditions. Nitric oxide (NO) is a well-known major initiator/mediator of intercellular signaling within culture medium during bystander responses. In this study, we investigated the NO-mediated bystander signal transduction induced by high-LET argon (Ar)-ion microbeam irradiation of normal human fibroblasts. Foci formation by DNA double-strand break repair proteins was induced in non-irradiated cells, which were co-cultured with those irradiated by high-LET Ar-ion microbeams in the same culture plate. Foci formation was suppressed significantly by pretreatment with an NO scavenger. Furthermore, NO-mediated reproductive cell death was also induced in bystander cells. Phosphorylation of NF-κB and Akt were induced during NO-mediated bystander signaling in the irradiated and bystander cells. However, the activation of these proteins depended on the incubation time after irradiation. The accumulation of cyclooxygenase-2 (COX-2), a downstream target of NO and NF-κB, was observed in the bystander cells 6 h after irradiation but not in the directly irradiated cells. Our findings suggest that Akt- and NF-κB-dependent signaling pathways involving COX-2 play important roles in NO-mediated high-LET heavy-ion-induced bystander responses. In addition, COX-2 may be used as a molecular marker of high-LET heavy-ion-induced bystander cells to distinguish them from directly irradiated cells, although this may depend on the time

Estimation of γ irradiation induced genetic damage by Ames test

International Nuclear Information System (INIS)

Hosoda, Eiko

1999-01-01

Mutation by 60 Co γ irradiation was studied in five different histidine-requiring auxotrophs of Salmonella typhimurium. The strains TA98 (sensitive to frameshift) and TA100 (sensitive to base-pair substitution) were irradiated (10-84 Gy and 45-317 Gy, respectively) and revertants were counted. TA98 exhibited radiation-induced revertants, 2.8 fold of spontaneous revertants, although no significant increase was detected in TA100. Then, three other frameshift-sensitive strains TA1537, TA1538 and TA94 were irradiated in a dose of 61-167 Gy. Only in TA94, revertants increased 3.5 fold. Since spontaneous revertants are known to be independent of cell density, a decrease of bacterial number by γ irradiation was confirmed not to affect the induced revertants by dilution test. Thus the standard Ames Salmonella assay identified γ irradiation was confirmed not to affect the induced revertants by dilution test. Thus the standard Ames Salmonella assay identified γ irradiation as a mutagenetic agent. The mutagenicity of dinitropyrene, a mutagen widely existing in food, and dismutagenicity of boiling water insoluble fraction of Hizikia fusiforme, edible marine alga, were tested on γ induced revertant formation in TA98 and TA94. Dinitropyrene synergistically increased γ induced revertants and Hizikia insoluble fraction reduced the synergistic effect of dinitropyrene dependently on the concentration. (author)

Induced defects in neutron irradiated GaN single crystals

International Nuclear Information System (INIS)

Park, I. W.; Koh, E. K.; Kim, Y. M.; Choh, S. H.; Park, S. S.; Kim, B. G.; Sohn, J. M.

2005-01-01

The local structure of defects in undoped, Si-doped, and neutron irradiated free standing GaN bulk crystals, grown by hydride vapor phase epitaxy, has been investigated by employing Raman scattering and cathodoluminescence. The GaN samples were irradiated to a dose of 2 x 10 17 neutrons in an atomic reactor at Korea Atomic Energy Research Institute. There was no appreciable change in the Raman spectra for undoped GaN samples before and after neutron irradiation. However, a forbidden transition, A 1 (TO) mode, appeared for a neutron irradiated Si-doped GaN crystal. Cathodoluminescence spectrum for the neutron irradiated Si-doped GaN crystal became much more broadened than that for the unirradiated one. The experimental results reveal the generation of defects with locally deformed structure in the wurtzite Si-doped GaN single crystal

Survivin and chromosome instability induced by X-irradiation

International Nuclear Information System (INIS)

Shen Bo; Ju Guizhi; Liu Yang

2006-01-01

Objective: To explore the biological effect of survivin on chromosome instability induced by X-ray irradiation. Methods: Immunocytochemistry was used to detect the expression of sutvivin in HeLa cells. Carrier pSUPER-SVV was transfected into HeLa cells to interfere the expression of survivin. Flow cytometry assay was applied to detect the occurrence of polyploid at 0 h, 4 h, 12 h, and 48 h after the HeLa cells transfected with pSUPER-SVV and irradiated with 4 Gy X-rays irradiation, and compared with the group irradiated with 4 Gy X-rays but no transfection. Results: The expression of survivin was down-regulated by transfecting with small hair RNA, its depression rate was estimated to be about 32.16% at 48 h after transfection. The occurrence of polyploid giant cells was higher in the 4 Gy X-ray irradiated group at 48 h after the irradiation than the control groups (P<0.001). Being expression of survivin interfered, the occurrence at 12 h or 48 h after irradiation, however, was about two times higher than that in the control group. Conclusion: X-ray irradiation can induce chromosome instability in HeLa cells and the effect could be enhanced by interfering the expression of surviving. It was suggested that survivin plays an important role in maintaining the stability of chromosome. (authors)

Effect of local x-irradiation on mice reproduction in two successive generations

International Nuclear Information System (INIS)

Strel'nikova, N.K.; Lisenkova, L.N.

1978-01-01

For an experimental assessment of the biologic effectiveness of a single exposure to local irradiation exposure in simulating the conditions of exposure in X ray studies, an experiment was carried out on white mice. Mice of two successive generations were exposed to local X irradiation in the eye region. The radiation was found to bring about changes in the reproductive function (such as sterility, reduced litter size and fertility of females); these changes being dose-dependent in a nonlinear manner. The biologic effect of irradiation was greater in the second-generation mice

Pattern of local recurrence after conservative surgery and whole-breast irradiation

International Nuclear Information System (INIS)

Freedman, Gary M.; Anderson, Penny R.; Hanlon, Alexandra L.; Eisenberg, Debra F.; Nicolaou, Nicos

2005-01-01

Purpose: Most recurrences in the breast after conservative surgery and whole-breast irradiation have been reported to occur within the same quadrant as the initial primary tumor. We analyzed the long-term risk of recurrence by area of the breast after whole-breast irradiation. Materials and Methods: In all, 1,990 women with Stage 0-II breast cancer were treated with conservative surgery and whole-breast irradiation from 1970-1998. Stage was ductal carcinoma in situ in 237, T1 in 1273, and T2 in 480 patients. Of 120 local recurrences, 71 were classified as true local (confined to the original quadrant) and 49 as elsewhere (involving outside the original quadrant). Kaplan-Meier methodology was used to calculate 5-year, 10-year, and 15-year rates of recurrence (95% confidence intervals in parentheses). The median follow-up is 80 months. Results: There was no apparent difference in the 15-year rate of true local vs. elsewhere recurrence, but the time to recurrence was different. The rate of true local recurrence was 2%, 5%, and 7% (5-9%) at 5, 10, and 15 years, respectively. The recurrences elsewhere in the breast were rare at 5 (1%) and 10 (2%) years, but increased to 6 (3-9%) at 15 years. This 15-year rate of elsewhere recurrence was half the rate of contralateral breast cancers of 13% (10-16%). Conclusions: Recurrence elsewhere in the breast is rare for the first 10 years, but by 15 years is nearly equal to true local recurrence even after whole-breast irradiation. The 15-year rate of elsewhere recurrence was half the rate of contralateral breast cancers. This may indicate a therapeutic effect of whole-breast radiation for other areas of the breast. Very long follow-up will be needed for partial breast irradiation with or without tamoxifen to show that the risk of elsewhere recurrence is not significantly different than after whole-breast irradiation

Irradiation-induced tumours of the head and neck

Energy Technology Data Exchange (ETDEWEB)

Aanesen, J P; Olofsson, J [Linkoepings Hoegskola (Sweden)

1979-09-01

Though irradiation-induced tumours are uncommon, they represent a well defined entity. At this Hospital, 14 irradiation-induced head and neck tumours were encountered in 11 patients over a 10-year period. The irradiation had been given for tuberculous lymphadenitis in 6 of the patients, for lupus vulgaris in one, and thyrotoxicosis in another; the other 3 patients had received radiotherapy for malignant tumours. The interval between the treatment and the diagnosis of the tumour disease ranged from 9 to 48 years (mean 32). Three of the patients had multiple tumours. In view of the risk of cancer-albeit a small one-associated with radiological diagnosis and radiotherapy, these should be performed only on strict indications, expecially in young patients.

Radiation induced muscositis as space flight risk. Model studies on X-ray and heavy ion irradiated typical oral mucosa models

International Nuclear Information System (INIS)

Tschachojan, Viktoria

2014-01-01

Humans in exomagnetospheric space are exposed to highly energetic heavy ion radiation which can be hardly shielded. Since radiation-induced mucositis constitutes a severe complication of heavy ion radiotherapy, it would also implicate a serious medical safety risk for the crew members during prolonged space flights such as missions to Moon or Mars. For assessment of risk developing radiation-induced mucositis, three-dimensional organotypic cultures of immortalized human keratinocytes and fibroblasts were irradiated with a 12 C particle beam at high energies or X-Rays. Immunofluorescence stainings were done from cryosections and radiation induced release of cytokines and chemokines was quantified by ELISA from culture supernatants. The major focuses of this study were on 4, 8, 24 and 48 hours after irradiation. The conducted analyses of our mucosa model showed many structural similarities with the native oral mucosa and authentic immunological responses to radiation exposure. Quantification of the DNA damage in irradiated mucosa models revealed about twice as many DSB after heavy-ion irradiation compared to X-rays at definite doses and time points, suggesting a higher gene toxicity of heavy ions. Nuclear factor κB activation was observed after treatment with X-rays or 12 C particles. An activation of NF κB p65 in irradiated samples could not be detected. ELISA analyses showed significantly higher interleukin 6 and interleukin 8 levels after irradiation with X-rays and 12 C particles compared to non-irradiated controls. However, only X-rays induced significantly higher levels of interleukin 1β. Analyses of TNF-α and IFN-γ showed no radiation-induced effects. Further analyses revealed a radiation-induced reduction in proliferation and loss of compactness in irradiated oral mucosa model, which would lead to local lesions in vivo. In this study we revealed that several pro-inflammatory markers and structural changes are induced by X-rays and heavy-ion irradiation

Irradiation spectrum and ionization-induced diffusion effects in ceramics

Energy Technology Data Exchange (ETDEWEB)

Zinkle, S.J. [Oak Ridge National Lab., TN (United States)

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.

Radiation-induced epigenetic alterations after low and high LET irradiations

International Nuclear Information System (INIS)

Aypar, Umut; Morgan, William F.; Baulch, Janet E.

2011-01-01

Epigenetics, including DNA methylation and microRNA (miRNA) expression, could be the missing link in understanding radiation-induced genomic instability (RIGI). This study tests the hypothesis that irradiation induces epigenetic aberrations, which could eventually lead to RIGI, and that the epigenetic aberrations induced by low linear energy transfer (LET) irradiation are different than those induced by high LET irradiations. GM10115 cells were irradiated with low LET X-rays and high LET iron (Fe) ions and evaluated for DNA damage, cell survival and chromosomal instability. The cells were also evaluated for specific locus methylation of nuclear factor-kappa B (NFκB), tumor suppressor in lung cancer 1 (TSLC1) and cadherin 1 (CDH1) gene promoter regions, long interspersed nuclear element 1 (LINE-1) and Alu repeat element methylation, CpG and non-CpG global methylation and miRNA expression levels. Irradiated cells showed increased micronucleus induction and cell killing immediately following exposure, but were chromosomally stable at delayed times post-irradiation. At this same delayed time, alterations in repeat element and global DNA methylation and miRNA expression were observed. Analyses of DNA methylation predominantly showed hypomethylation, however hypermethylation was also observed. We demonstrate that miRNA expression levels can be altered after X-ray irradiation and that these miRNA are involved in chromatin remodeling and DNA methylation. A higher incidence of epigenetic changes was observed after exposure to X-rays than Fe ions even though Fe ions elicited more chromosomal damage and cell killing. This distinction is apparent at miRNA analyses at which only three miRNA involved in two major pathways were altered after high LET irradiations while six miRNA involved in five major pathways were altered after low LET irradiations. This study also shows that the irradiated cells acquire epigenetic changes suggesting that epigenetic aberrations may arise in the

Radiation-induced epigenetic alterations after low and high LET irradiations

Energy Technology Data Exchange (ETDEWEB)

Aypar, Umut, E-mail: uaypa001@umaryland.edu [Department of Radiation Oncology, Radiation Oncology Research Laboratory, University of Maryland School of Medicine, Baltimore, MD 21201 (United States); Morgan, William F. [Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Baulch, Janet E. [Department of Radiation Oncology, Radiation Oncology Research Laboratory, University of Maryland School of Medicine, Baltimore, MD 21201 (United States)

2011-02-10

Epigenetics, including DNA methylation and microRNA (miRNA) expression, could be the missing link in understanding radiation-induced genomic instability (RIGI). This study tests the hypothesis that irradiation induces epigenetic aberrations, which could eventually lead to RIGI, and that the epigenetic aberrations induced by low linear energy transfer (LET) irradiation are different than those induced by high LET irradiations. GM10115 cells were irradiated with low LET X-rays and high LET iron (Fe) ions and evaluated for DNA damage, cell survival and chromosomal instability. The cells were also evaluated for specific locus methylation of nuclear factor-kappa B (NF{kappa}B), tumor suppressor in lung cancer 1 (TSLC1) and cadherin 1 (CDH1) gene promoter regions, long interspersed nuclear element 1 (LINE-1) and Alu repeat element methylation, CpG and non-CpG global methylation and miRNA expression levels. Irradiated cells showed increased micronucleus induction and cell killing immediately following exposure, but were chromosomally stable at delayed times post-irradiation. At this same delayed time, alterations in repeat element and global DNA methylation and miRNA expression were observed. Analyses of DNA methylation predominantly showed hypomethylation, however hypermethylation was also observed. We demonstrate that miRNA expression levels can be altered after X-ray irradiation and that these miRNA are involved in chromatin remodeling and DNA methylation. A higher incidence of epigenetic changes was observed after exposure to X-rays than Fe ions even though Fe ions elicited more chromosomal damage and cell killing. This distinction is apparent at miRNA analyses at which only three miRNA involved in two major pathways were altered after high LET irradiations while six miRNA involved in five major pathways were altered after low LET irradiations. This study also shows that the irradiated cells acquire epigenetic changes suggesting that epigenetic aberrations may arise

Irradiation-induced stress relaxation of Eurofer97 steel

International Nuclear Information System (INIS)

Luzginova, N.V.; Jong, M.; Rensman, J.W.; Hegeman, J.B.J.; Laan, J.G. van der

2011-01-01

The irradiation-induced stress relaxation behavior of Eurofer97 at 300 deg. C up to 3.4 dpa and under pre-stress loads typical for the ITER applications is investigated. The bolt specimens are pre-loaded from 30% to 90% of the yield strength. To verify the results obtained with the pre-stressed bolts, bent strips were investigated as well. The strips are bent into a pre-defined radius in order to achieve similar pre-stress levels. The irradiation-induced stress relaxation is found to be independent of the pre-stress level. 10-12% of the stress relaxation in Eurofer97 may be reached after a dose of 0.1 dpa, and after an irradiation dose of 2.7 dpa 42-47% of the original pre-stress is retained.

Influence of locoregional irradiation on local control and survival in breast cancer

International Nuclear Information System (INIS)

Cutuli, B.

1998-01-01

Locoregional control is a crucial step in the achievement of breast cancer cure. In ductal carcinoma in situ, breast irradiation significantly reduces the rates of local recurrence whatever the histological subtypes, as demonstrated by the NSABP-B17 trial (25.8 % of local recurrences without radiotherapy vs. 11.4 % with radiotherapy). In infiltrating breast carcinomas, complementary breast irradiation has been shown to significantly improve the local control and slightly the overall survival in five randomized trials. Following mastectomy, locoregional irradiation clearly reduces the chest wall and nodal relapse rates, especially in case of lesions more than 5 cm or with nodal involvement and/or large lymphatic or vascular emboli. Two recent randomized trials confirmed the benefit of well-adapted locoregional irradiation in all subgroups, especially in patients with one to three axillary involves nodes. In the Danish trial (including pre-menopausal high-risk women), radiotherapy reduced locoregional relapses from 32 to 9 % (p<0.001) and increased the 10-year survival rate from 45 to 54% (p<0.001). In the Canadian trial, locoregional relapse rate decreased from 25 to 13 % and the 10-year survival rate increased from 56 to 65 %. The meta-analysis published in 1995 by the EBCTCG showed only a modest benefit due to locoregional irradiation in breast cancer. However, when small or old trials were excluded due to imperfect methodology or inadequate irradiation techniques, the benefit of modern radiotherapy became much more evident in a population of 7,840 patients. Locoregional irradiation appears to be able to reduce the risk of metastatic evolution occurring after local or nodal relapse and must be integrated in a multidisciplinary strategy. Treatment toxicity (especially toxicity due to irradiation of internal mammary nodes) is of special concern, as anthracycline-based chemotherapy is prescribed more often. The use of a direct field, with at least 60 % of the dose

Selection of patients for re-irradiation with local implants in carcinomas of oropharynx and tongue

International Nuclear Information System (INIS)

Langlois, D.; Hoffstetter, S.; Pernot, M.

1988-01-01

Between 1972 and 1984, 123 patients with recurrent or new primary carcinomas in previously irradiated areas of soft palate, tonsil, base of tongue or mobile tongue were re-irradiated with iridium-192 afterloading techniques. The average re-irradiation dose was 62 Gy (31-84 Gy) and the total dose 131 Gy (92-162 Gy); only 28 cases of mucosal necrosis were observed (23%). Two and 5 years actuarial local control rates were 67% and 59% and survival rates 48% and 24% respectively. Death was related to local tumor in 48 cases, metastases in 8 cases and intercurrent disease in 39 cases. We analysed the effect on survival and local control of age, initial tumor site and volume, previous surgery, time between first irradiation and re-irradiation, doses, dose rate, and techniques of brachytherapy. With this analysis as background, we recommend the use of salvage brachytherapy for patients with a) small tumors of soft palate, tonsil or mobile tongue without synchronic lymph node metastases, b) long time interval between first irradiation and re-irradiation, c) new primary tumors (rather than recurrence of first tumor), and d) no previous local surgery. A high re-irradiation dose given with low dose rate is recommended. (orig.)

Modelling irradiation-induced softening in BCC iron by crystal plasticity approach

International Nuclear Information System (INIS)

Xiao, Xiazi; Terentyev, Dmitry; Yu, Long; Song, Dingkun; Bakaev, A.; Duan, Huiling

2015-01-01

Crystal plasticity model (CPM) for BCC iron to account for radiation-induced strain softening is proposed. CPM is based on the plastically-driven and thermally-activated removal of dislocation loops. Atomistic simulations are applied to parameterize dislocation-defect interactions. Combining experimental microstructures, defect-hardening/absorption rules from atomistic simulations, and CPM fitted to properties of non-irradiated iron, the model achieves a good agreement with experimental data regarding radiation-induced strain softening and flow stress increase under neutron irradiation. - Highlights: • A stress- and thermal-activated defect absorption model is proposed for the dislocation-loop interaction. • A temperature-dependent plasticity theory is proposed for the irradiation-induced strain softening of irradiated BCC metals. • The numerical results of the model match with the corresponding experimental data.

Modelling irradiation-induced softening in BCC iron by crystal plasticity approach

Energy Technology Data Exchange (ETDEWEB)

Xiao, Xiazi [State Key Laboratory for Turbulence and Complex System, Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing 100871 (China); CAPT, HEDPS and IFSA Collaborative Innovation Center of MoE, Peking University, Beijing 100871 (China); Terentyev, Dmitry, E-mail: dterenty@SCKCEN.BE [Structural Material Group, Institute of Nuclear Materials Science, SCK-CEN, Mol (Belgium); Yu, Long; Song, Dingkun [State Key Laboratory for Turbulence and Complex System, Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing 100871 (China); Bakaev, A. [Structural Material Group, Institute of Nuclear Materials Science, SCK-CEN, Mol (Belgium); Duan, Huiling, E-mail: hlduan@pku.edu.cn [State Key Laboratory for Turbulence and Complex System, Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing 100871 (China); CAPT, HEDPS and IFSA Collaborative Innovation Center of MoE, Peking University, Beijing 100871 (China)

2015-11-15

Crystal plasticity model (CPM) for BCC iron to account for radiation-induced strain softening is proposed. CPM is based on the plastically-driven and thermally-activated removal of dislocation loops. Atomistic simulations are applied to parameterize dislocation-defect interactions. Combining experimental microstructures, defect-hardening/absorption rules from atomistic simulations, and CPM fitted to properties of non-irradiated iron, the model achieves a good agreement with experimental data regarding radiation-induced strain softening and flow stress increase under neutron irradiation. - Highlights: • A stress- and thermal-activated defect absorption model is proposed for the dislocation-loop interaction. • A temperature-dependent plasticity theory is proposed for the irradiation-induced strain softening of irradiated BCC metals. • The numerical results of the model match with the corresponding experimental data.

Irradiation-induced precipitates in a neutron irradiated 304 stainless steel studied by three-dimensional atom probe

Energy Technology Data Exchange (ETDEWEB)

Toyama, T., E-mail: ttoyama@imr.tohoku.ac.jp [International Research Center for Nuclear Materials Science, Institute for Materials Research, Tohoku University, Narita-cho 2145-2, Oarai, Ibaraki 311-1313 (Japan); Nozawa, Y. [International Research Center for Nuclear Materials Science, Institute for Materials Research, Tohoku University, Narita-cho 2145-2, Oarai, Ibaraki 311-1313 (Japan); Van Renterghem, W. [SCK-CEN, Nuclear Materials Science Institute, Boeretang 200, 2400 Mol (Belgium); Matsukawa, Y.; Hatakeyama, M.; Nagai, Y. [International Research Center for Nuclear Materials Science, Institute for Materials Research, Tohoku University, Narita-cho 2145-2, Oarai, Ibaraki 311-1313 (Japan); Al Mazouzi, A. [EDF R and D, Avenue des Renardieres Ecuelles, 77818 Moret sur Loing Cedex (France); Van Dyck, S. [SCK-CEN, Nuclear Materials Science Institute, Boeretang 200, 2400 Mol (Belgium)

2011-11-15

Highlights: > Irradiation-induced precipitates in a 304 stainless steel were investigated by three-dimensional atom probe. > The precipitates were found to be {gamma}' precipitates (Ni{sub 3}Si). > Post-irradiation annealing was performed to discuss the contribution of the precipitates to irradiation-hardening. - Abstract: Irradiation-induced precipitates in a 304 stainless steel, neutron-irradiated to a dose of 24 dpa at 300 deg. C in the fuel wrapper plates of a commercial pressurized water reactor, were investigated by laser-assisted three-dimensional atom probe. A high number density of 4 x 10{sup 23} m{sup -3} of Ni-Si rich precipitates was observed, which is one order of magnitude higher than that of Frank loops. The average diameter was {approx}10 nm and the average chemical composition was 40% Ni, 14% Si, 11% Cr and 32% Fe in atomic percent. Over a range of Si concentrations, the ratio of Ni to Si was {approx}3, close to that of {gamma}' precipitate (Ni{sub 3}Si). In some precipitates, Mn enrichment inside the precipitate and P segregation at the interface were observed. Post-irradiation annealing was performed to discuss the contribution of the precipitates to irradiation-hardening.

Induced disease resistance of satsuma mandarings against penicillium digitatum by gamma irradiation

International Nuclear Information System (INIS)

Jeong, Rae Dong

2017-01-01

Gamma irradiation, which is a type of ionizing radiation, can be used as a fruit inducible factor. In the present study, the effects of gamma irradiation on the resistance of mandarin fruits against Penicillium digitatum, the causal agent of postharvest green mold disease, were investigated. Pretreatment of a low dose of gamma irradiation effectively reduced the disease incidence and lesion diameter of mandarin fruits inoculated with P. digatatum during storage for 14 d. Interestingly, exposed to 400 Gy of gamma irradiation significantly maintained firmness and stimulated the synthesis of defense-related enzymes, (e.g., β-1,3-glucanase, phenylalanine, peroxidase, and polyphenol oxidase) and pathogenesis-related (PR) genes (e.g., PR-1 and PR-2). Therefore, the gamma irradiation-induced resistance against P. digatatum involves both changes of phenolic compounds and the induction of expression of defense-related genes. In addition, scanning electron microscopy analysis revealed that induced disease resistance by gamma irradiation signifcantly inhibits the growth of P. digatatum in mandarin fruits. These results suggest that the exposure of gamma irradiation is a potential methods for inducing the disease resistance of fruit to postharvest fungal pathogens and for extending the postharvest life of mandarin fruit

Induced disease resistance of satsuma mandarings against penicillium digitatum by gamma irradiation

Energy Technology Data Exchange (ETDEWEB)

Jeong, Rae Dong [Dept. of Applied Biology, Institute of Environmentally Friendly Agriculture, Chonnam National University, Gwangju (Korea, Republic of)

2017-06-15

Gamma irradiation, which is a type of ionizing radiation, can be used as a fruit inducible factor. In the present study, the effects of gamma irradiation on the resistance of mandarin fruits against Penicillium digitatum, the causal agent of postharvest green mold disease, were investigated. Pretreatment of a low dose of gamma irradiation effectively reduced the disease incidence and lesion diameter of mandarin fruits inoculated with P. digatatum during storage for 14 d. Interestingly, exposed to 400 Gy of gamma irradiation significantly maintained firmness and stimulated the synthesis of defense-related enzymes, (e.g., β-1,3-glucanase, phenylalanine, peroxidase, and polyphenol oxidase) and pathogenesis-related (PR) genes (e.g., PR-1 and PR-2). Therefore, the gamma irradiation-induced resistance against P. digatatum involves both changes of phenolic compounds and the induction of expression of defense-related genes. In addition, scanning electron microscopy analysis revealed that induced disease resistance by gamma irradiation signifcantly inhibits the growth of P. digatatum in mandarin fruits. These results suggest that the exposure of gamma irradiation is a potential methods for inducing the disease resistance of fruit to postharvest fungal pathogens and for extending the postharvest life of mandarin fruit.

Preliminary examination of induced radioactivity in pepper by 10 MeV electron irradiation

International Nuclear Information System (INIS)

Katayama, Tadashi; Furuta, Masakazu; Sibata, Setsuko; Ito, Norio; Mizohata, Akira; Matsunami, Tadao; Toratani, Hirokazu; Takeda, Atsuhiko.

1991-01-01

β-ray measurement was performed on 10 MeV electron-irradiated black pepper and white pepper with liquid scintillation counter in order to reconfirm the wholesomeness of irradiated foods and present unambiguous data to general consumers concerning about the induced radioactivity in the irradiated foods. In irradiated black pepper no radioactivity other than from natural source, un-irradiated one, was detected. But in irradiated white pepper, it was suggested that induced radioactivity might be detected if the detection method was more improved. (author)

Enhanced electrochemical etching of ion irradiated silicon by localized amorphization

Energy Technology Data Exchange (ETDEWEB)

Dang, Z. Y.; Breese, M. B. H. [Centre for Ion Beam Applications (CIBA), Department of Physics, National University of Singapore Singapore 117542 (Singapore); Lin, Y.; Tok, E. S. [Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore); Vittone, E. [Physics Department, NIS Excellence Centre and CNISM, University of Torino, via Pietro Giuria 1, 10125 Torino (Italy)

2014-05-12

A tailored distribution of ion induced defects in p-type silicon allows subsequent electrochemical anodization to be modified in various ways. Here we describe how a low level of lattice amorphization induced by ion irradiation influences anodization. First, it superposes a chemical etching effect, which is observable at high fluences as a reduced height of a micromachined component. Second, at lower fluences, it greatly enhances electrochemical anodization by allowing a hole diffusion current to flow to the exposed surface. We present an anodization model, which explains all observed effects produced by light ions such as helium and heavy ions such as cesium over a wide range of fluences and irradiation geometries.

Adjuvant irradiation improves the outcome of patients with rectal cancer following local excision

International Nuclear Information System (INIS)

Chakravarti, Arnab; Willett, Christopher G.; Shellito, Paul; Kaufman, Donald; Daley, William J.

1997-01-01

PURPOSE: the long-term outcomes of patients undergoing local excision with or without pelvic irradiation were examined to define the role of adjuvant irradiation following local excision of T1 and T2 rectal cancers. METHODS: From January 1966 to January 1997, 114 patients underwent local excision for rectal cancer. Fifty-nine patients underwent local excision alone, and 55 patients received adjuvant pelvic irradiation (45 Gy to 65.8 Gy)+/-concurrent 5-fluorouracil chemotherapy. Outcome was assessed by treatment, stage, and pathologic features of tumor grade and lymphatic/venous vessel involvement. RESULTS: Of the 114 patients treated by local excision, 90 had T1/T2 tumors. The 5-year actuarial local control (LC) and recurrence-free survival (RFS) of these 90 patients are shown (with numbers of patients at risk at 5 years) in the table below. The 5-year actuarial local control and recurrence-free survival (RFS) for T1/T2 patients treated by local excision alone was 85% and 77%, respectively. The corresponding values for patients undergoing local excision and adjuvant irradiation alone were 88% and 78%, respectively. All 20 patients treated by adjuvant chemoradiation achieved 5-year actuarial local control and had a recurrence-free survival of 88%. The improved outcomes in the adjuvant radiation group become more impressive when the higher T stage distribution of this group is considered. Fifty-five percent of the group receiving adjuvant radiation were stage T2 compared to only 14% of patients treated by local excision alone. Subgroup analysis was performed on those features recognized as poor prognostic factors including poorly differentiated histology and lymphatic vascular invasion. Patients in the local excision alone group with one or more adverse pathologic features had reduced rates of local control compared to those with the absence of such features (38% vs. 91%, respectively, p=0.02). In comparison, the 5 patients with poor prognostic features treated by

Effect of irradiation on the dental pulp tissues in streptozotocin-induced diabetic rats

International Nuclear Information System (INIS)

Kang, Ho Duk; Hwang, Eui Hwan; Lee, Sang Rae

2005-01-01

To observe the histological changes in the pulp tissues of mandibular molars in streptozotocin-induced diabetic rats after irradiation. The male Sprague-Dawley rats weighing approximately 250 gm were divided into four groups : control, diabetes, irradiation, and diabetes-irradiation groups. Diabetes mellitus was induced in the rats by injecting streptozotocin. Rats in control and irradiation groups were injected with citrate buffer only. After 5 days, the head and neck region of the rats in irradiation and diabetes-irradiation groups were irradiated with a single absorbed dose of 10 Gy. All the rats were sacrificed at 3, 7, 14, 21, and 28 days after irradiation. The specimen including the mandibular molars were sectioned and observed using a histopathological method. In the diabetes group, capillary dilatation was observed. However, there was no obvious morphologic alteration of the odontoblasts. In the irradiation group, generalized necrosis of the dental pulp tissues was observed. Vacuolation of the odontoblasts and dilatation of the capillaries were noted in the early experimental phases. In the diabetes-irradiation group, generalized degeneration of the dental pulp tissues was observed. Vacuolation of the dental pulp cells and the odontoblasts was noted in the late experimental phases. This experiment suggest that dilatation of the capillaries in the dental pulp tissue is induced by diabetic state, and generalized degeneration of the dental pulp tissues is induced by irradiation of the diabetic group.

Local control and survival after external irradiation for adenocarcinoma of the prostate

International Nuclear Information System (INIS)

Rangala, N.; Cox, J.D.; Byhardt, R.W.; Wilson, J.F.; Greenberg, M.; Conceicao, A.L.D.

1982-01-01

From 1966 through 1978, 128 patients with biopsy-proven adenocarcinoma of the prostate underwent external irradiation to the entire pelvis followed by additional irradiation with a field that encompassed the entire prostate with generous margins. Local recurrence was diagnosed when palpable regrowth occurred and was confirmed by biopsy. Eighteen patients (14%) had local recurrence. Actuarial (life table) local recurrence rates, however, were 24% for both for Stage B and C patients. Actuarial five year survival was 100% for the 10 Stage A patients, 91% for the 25 Stage B, and 78% for the 93 Stage C patients. Actuarial five year disease-free survival was 59% for Stage B and 69% for Stage C patients. Local recurrence was affected by the total dose to the whole pelvis and the dose at the center of the prostate. Disease-free survival was influenced by differentiation. High dose external irradiation to the prostate and regional lymph nodes offers the greatest probability of long-term disease-free survival for patients with localized disease. Late bowel complications were seen in 14 patients (11%), two of whom required colostomies. Late urinary tract complications were observed in five patients (4%)

Early esophageal carcinoma treated with intracavitary irradiation

International Nuclear Information System (INIS)

Hishikawa, Y.; Tanaka, S.; Miura, T.

1985-01-01

Five patients with early esophageal carcinoma were treated by 6-12 Gy of intracavitary irradiation following 50-60 Gy of external irradiation as a boost therapy. Surgery was not performed in these cases. None of the patients had local recurrence after radiation therapy, as demonstrated by esophagography and endoscopy. Three patients have been alive for 1-3 years 10 months. Esophageal ulceration induced by intracavitary irradiation has occurred in three of the five patients; however, intracavitary irradiation is still a beneficial treatment because of its efficacy in controlling local lesions and because radiation ulceration can eventually be cured. Intracavitary irradiation is recommended to follow external irradiation as a boost therapy for the treatment of early esophageal carcinoma

Irradiation creep induced anisotropy in a/2 dislocation populations

International Nuclear Information System (INIS)

Gelles, D.S.

1984-05-01

The contribution of anisotropy in Burgers vector distribution to irradiation creep behavior has been largely ignored in irradiation creep models. However, findings on Frank loops suggest that it may be very important. Procedures are defined to identify the orientations of a/2 Burgers vectors for dislocations in face-centered cubic crystals. By means of these procedures the anisotropy in Burgers vector populations was determined for three Nimonic PE16 pressurized tube specimens irradiated under stress. Considerable anisotropy in Burgers vector population develops during irradiation creep. It is inferred that dislocation motion during irradiation creep is restricted primarily to a climb of a/2 dislocations on 100 planes. Effect of these results on irradiation creep modeling and deformation induced irradiation growth is considered

Tranexamic acid suppresses ultraviolet B eye irradiation-induced melanocyte activation by decreasing the levels of prohormone convertase 2 and alpha-melanocyte-stimulating hormone.

Science.gov (United States)

Hiramoto, Keiichi; Yamate, Yurika; Sugiyama, Daijiro; Takahashi, Yumi; Mafune, Eiichi

2014-12-01

Tranexamic acid (trans-4-aminomethylcyclohexanecarboxylic acid) is a medicinal amino acid used in skin whitening care. This study examined the effects of tranexamic acid on the melanocyte activation of the skin induced by an ultraviolet (UV) B eye irradiation. The eye or ear was locally exposed to UVB at a dose of 1.0 kJ/m(2) using a 20SE sunlamp after covering the remaining body surface with aluminum foil. UVB eye irradiation induced melanocyte activation of the skin, similar to that observed following UVB ear irradiation, which was suppressed by the administration of tranexamic acid treatment. The plasma α-melanocyte-stimulating hormone (α-MSH) content was increased by UVB irradiation of the eye; however, the increase in α-MSH was suppressed by tranexamic acid treatment. In addition, UVB eye irradiation induced the up-regulation of prohormone convertase (PC) 2 in the pituitary gland. Meanwhile, the increase in PC2 induced by UVB eye irradiation was suppressed by tranexamic acid treatment. These results clearly indicate that tranexamic acid decreases the expression of PC2, which cleavages from proopiomelanocortin to α-MSH in the pituitary gland, thereby suppressing melanocyte activation. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Search for the lowest irradiation dose from literatures on radiation-induced breast cancer

Energy Technology Data Exchange (ETDEWEB)

Yoshizawa, Y; Kusama, T [Tokyo Univ. (Japan). Faculty of Medicine

1975-12-01

A survey of past case reports concerning radiation-induced breast cancer was carried out in order to find the lowest irradiation dose. The search of literature published since 1951 revealed 10 cases of radiation-induced breast cancer. Only 5 cases had precise descriptions of the irradiation dose. The lowest irradiation dose was estimated at 1470 rads in the case of external X-ray irradiation for tuberous angioma. All of cases of radiation-induced breast cancer had received radiation for the treatment of nonmalignant tumors, such as pulmonary tuberculosis, mastitis, and tuberous angioma. There also were three statistical studies. The first concerned atomic bomb survivors, the second, pulmoanry tuberculous patients subjected to frequent fluoroscopies, and the third, patients of acute post partum mastitis. These statistical studies had revealed a significant increase in the incidence of breast cancer in the irradiated group, but there was little information about the lowest irradiation dose. It was noticed that radiation-induced breast cancer was more numerous in the upper inner quadrant of the breast. Most histopathological findings of radiation-induced breast cancer involved duct cell carcinoma. The latent period was about 15 years.

Edaravone protects human peripheral blood lymphocytes from γ-irradiation-induced apoptosis and DNA damage.

Science.gov (United States)

Chen, Liming; Liu, Yinghui; Dong, Liangliang; Chu, Xiaoxia

2015-03-01

Radiation-induced cellular injury is attributed primarily to the harmful effects of free radicals, which play a key role in irradiation-induced apoptosis. In this study, we investigated the radioprotective efficacy of edaravone, a licensed clinical drug and a powerful free radical scavenger that has been tested against γ-irradiation-induced cellular damage in cultured human peripheral blood lymphocytes in studies of various diseases. Edaravone was pre-incubated with lymphocytes for 2 h prior to γ-irradiation. It was found that pretreatment with edaravone increased cell viability and inhibited generation of γ-radiation-induced reactive oxygen species (ROS) in lymphocytes exposed to 3 Gy γ-radiation. In addition, γ-radiation decreased antioxidant enzymatic activity, such as superoxide dismutase and glutathione peroxidase, as well as the level of reduced glutathione. Conversely, treatment with 100 μM edaravone prior to irradiation improved antioxidant enzyme activity and increased reduced glutathione levels in irradiated lymphocytes. Importantly, we also report that edaravone reduced γ-irradiation-induced apoptosis through downregulation of Bax, upregulation of Bcl-2, and consequent reduction of the Bax:Bcl-2 ratio. The current study shows edaravone to be an effective radioprotector against γ-irradiation-induced cellular damage in lymphocytes in vitro. Finally, edaravone pretreatment significantly reduced DNA damage in γ-irradiated lymphocytes, as measured by comet assay (% tail DNA, tail length, tail moment, and olive tail moment) (p edaravone offers protection from radiation-induced cytogenetic alterations.

Molecular dynamics for irradiation driven chemistry

DEFF Research Database (Denmark)

Sushko, Gennady B.; Solov'yov, Ilia A.; Solov'yov, Andrey V.

2016-01-01

A new molecular dynamics (MD) approach for computer simulations of irradiation driven chemical transformations of complex molecular systems is suggested. The approach is based on the fact that irradiation induced quantum transformations can often be treated as random, fast and local processes...... that describe the classical MD of complex molecular systems under irradiation. The proposed irradiation driven molecular dynamics (IDMD) methodology is designed for the molecular level description of the irradiation driven chemistry. The IDMD approach is implemented into the MBN Explorer software package...... involving small molecules or molecular fragments. We advocate that the quantum transformations, such as molecular bond breaks, creation and annihilation of dangling bonds, electronic charge redistributions, changes in molecular topologies, etc., could be incorporated locally into the molecular force fields...

Analytical electron microscopy of neutron-irradiated reactor alloys

International Nuclear Information System (INIS)

Thomas, L.E.

1982-01-01

Exposure to the high neutron fluxes and temperatures from 400 to 650 0 C in the core region of a fast breeder reactor profoundly alters the microstructure and properties of structural steels and superalloys. The development of irradiation-induced voids, dislocations and precipitates, as well as segregation of alloying elements on a microscopic scale has been related to macroscopic swelling, creep, hardening and embrittlement which occur during prolonged exposures in reactor. Microanalytical studies using TEM/STEM methods, primarily energy dispersive x-ray (EDX) microanalysis, have greatly aided understanding of alloy behavior under irradiation. The main uses of analytical electron microscopy in studying irradiated alloys have been the identification of irradiation-induced precipitates and determination of the changes in local composition due to irradiation-induced solute segregation

Preliminary examination of induced radio activity in pepper by 10 MeV electron irradiation

International Nuclear Information System (INIS)

Furuta, Masakazu; Katayama, Tadashi; Ito, Norio; Mizohata, Akira; Matsunami, Tadao; Toratani, Hirokazu; Takeda, Atsuhiko

1989-01-01

β-ray measurement was performed on 10 MeV electron-irradiated black pepper and white pepper in order to reconfirm the wholesomeness of irradiated food and present unambiguous data to general consumers concerning about the induced radioactivity in the irradiated foods. From elemental composition of the samples and investigation of photonuclear reactions, several β-emmitters were listed up. But no radioactivity other than from natural sources was detected in the irradiated sample by β-ray counting with 2 π gass flow counter, suggesting that the induced β-emmitters in the irradiated sample was below the detection limit of its induced radioactivity. (author)

Application of local approach to quantitative prediction of degradation in fracture toughness of steels due to pre-straining and irradiation

International Nuclear Information System (INIS)

Miyata, T.; Tagawa, T.

1996-01-01

Degradation of cleavage fracture toughness for low carbon steels due to pre-straining and irradiation was investigated on the basis of the local fracture criterion approach. Formulation of cleavage fracture toughness through the statistical modelling proposed by BEREMIN has been simplified by the present authors to the expression involving yield stress and cleavage fracture stress of materials. A few percent pre-strain induced by cold rolling deteriorates significantly the cleavage fracture toughness. Ductile-brittle transition temperature is increased to more than 70 C higher by 8% straining in 500 MPa class high strength steel. Quantitative prediction of degradation has been successfully examined through the formulation of the cleavage fracture toughness. Analytical and experimental results indicate that degradation in toughness is caused by the increase of flow stress in pre-strained materials. Quantitative prediction of degradation of toughness due to irradiation has been also examined for the past experiments on the basis of the local fracture criterion approach. Analytical prediction from variance of yield stress by irradiation is well consistent with the experimental results. (orig.)

Irradiation deformation due to SIPA induced dislocation anisotropy

International Nuclear Information System (INIS)

Woo, CH.

1980-02-01

A contribution to irradiation deformation resulting from the stress-induced preferred adsorption (SIPA) effect is considered. SIPA causes a variation of the growth rates of irradiation-generated dislocation loops, according to the alignment of their Burgers vectors with respect to the applied stress. A prolinged period under an applied stress then creates an anisotropic dislocation structure in which the majority of dislocations have their Burgers vectors in alignment with the stress. In the presence of 'neutral' sinks, the resulting anisotropic dislocation structure causes plastic deformation similar to the way in which irradiation growth occurs in zirconium. This mechanism is called SIPA-induced growth (SIG). We have shown that SIG is very significant in comparison to SIPA, except when little or no loop growth has occurred during the period the stress is applied. This report contains the detailed formulation and derivation of the formulae for the evaluation of the contribution due to SIG. (auth)

Radiation-induced organogenesis: effects of irradiated medium and its components on tobacco tissue culture

International Nuclear Information System (INIS)

Degani, N.

1975-01-01

Gamma irradiated medium induces the formation of buds in non-irradiated dark growth tobacco callus (Nicotiana tabacum Var. Wisconsin No.38). Experiments were conducted to determine the component(s) of the medium that is effective in this radiation-induced organogenesis. Fraction of medium were irradiated singly and in combination, then combined with non-irradiated fractions to form the complete growth medium. The results showed that irradiated indoleacetic acid (IAA) was not the effective component in the induction of organogensis. Omission of IAA from the medium resulted in the formation of buds, as expected. Irradiated myo-inositol induced organogenesis more consistently than the other irradiated components. The age of the inoculum tissue and its passage number from the tobacco stem affected the potency of the tobacco callus to organise. (author)

Effect of irradiation on the periodontal tissues in streptozotocin-induced diabetic rats

International Nuclear Information System (INIS)

Park, Dong Sin; Hwang, Eui Hwan; Lee, Sang Rae

2005-01-01

To observe the histopathological changes in the periodontal tissues of mandibular molars in streptozotocin-induced diabetic rats after irradiation. The male Sprague-Dawley rats weighing approximately 250 gm were divided into four groups; control, diabetes, irradiation, and diabetes - irradiation groups. Diabetes mellitus was induced in the rats by injecting streptozotocin. Rats in the control and irradiation groups were injected with citrate buffer only. After 5 days, the head and neck region of the rats in irradiation and diabetes - irradiation groups were irradiated with a single absorbed dose of 10 Gy. All the rats were sacrificed at 3, 7, 14, 21, and 28 days after irradiation. The specimen including the mandibular molars were sectioned and observed using a histopathological method. In the diabetes group, osteoclastic activity was observed in the alveolar bone and the root throughout the period of experiment. Also, osteoblastic and fibroblastic activities were markedly decreased. In the irradiation group, the osteoclasts were observed in the alveolar bone and the dilated capillaries were increased in the early experimental phases. However, vigorous osteoblastic activity was noted in the late experimental phases. In the diabetes- irradiation group, osteoblastic activity in the alveolar bone and the root was observed in the early experimental phases. However, there were no resorption and osteoblastic activity in the alveolar bone and the root in the late experimental phases, and obvious atrophic change of fibrous tissues was noted. This experiment suggests that osteoblastic activity was caused by irradiation in the late experimental phases, but atrophic change of the periodontal ligament tissues was induced after irradiation in diabetic state.

Polymerization of sodium methacrylate induced by irradiation

International Nuclear Information System (INIS)

Galvan S, A.

1998-01-01

This work has two objectives, first: it is pretended to localize the lines of carbon links in its IR spectra, and second: following the polymerization of sodium methacrylate according to that it is irradiated with gamma rays. (Author)

Colorectal irradiation induced immune response: 'toll like receptors' therapeutic manipulation

International Nuclear Information System (INIS)

Lacave-Lapalun, Jean-Victor

2013-01-01

Exposure of the abdomino-pelvic sphere to ionizing radiation is associated with a high incidence of complications. Radiation therapy may cause short and / or long-term harmful effects. In the most severe cases and in the absence of heavy treatments, the appearance of ulcers may induce the death of patients. Clinical trials are being conducted with Mesenchymal Stem Cells (MSC) to cure theses complications. Others studies indicate that the injection of bacterial motifs limits the radiotoxicity in the intestine. They stimulate receptors (Toll-Like- Receptors (TLR)) located on the surface of epithelial and intestinal immune cells. The first aim of this doctoral work is to characterize the effects of TLR stimulation on immunity and tissue repair using a model of localized colorectal irradiation at 20 Gy (acute effects of radiotherapy) on a rat. The thesis then aims to potentiate the effects of the MSC treatment when adding TLR ligands upon localized colorectal irradiation at 27 Gy (accidental complications). This work, using a 20 Gy exposure, show that TLR stimulation improves homeostasis (normalization of T cells, induction of regulatory T cells (Treg) and macrophages 'anti-inflammatory' M2). On the 27 Gy colorectal model, the injection of TLR ligand before CSM transplant improves the immune climate by reducing pro-inflammatory cytokines and inducting Treg and M2 cells. These modulations could contribute to improving the implantation and effectiveness of CSM. The observations have all shown that the stimulation of immunity is an approach to minimize radiation-induced lesions. (author) [fr

Size-Tuned Plastic Flow Localization in Irradiated Materials at the Submicron Scale

Science.gov (United States)

Cui, Yinan; Po, Giacomo; Ghoniem, Nasr

2018-05-01

Three-dimensional discrete dislocation dynamics (3D-DDD) simulations reveal that, with reduction of sample size in the submicron regime, the mechanism of plastic flow localization in irradiated materials transitions from irradiation-controlled to an intrinsic dislocation source controlled. Furthermore, the spatial correlation of plastic deformation decreases due to weaker dislocation interactions and less frequent cross slip as the system size decreases, thus manifesting itself in thinner dislocation channels. A simple model of discrete dislocation source activation coupled with cross slip channel widening is developed to reproduce and physically explain this transition. In order to quantify the phenomenon of plastic flow localization, we introduce a "deformation localization index," with implications to the design of radiation-resistant materials.

Radiation-Induced Epigenetic Alterations after Low and High LET Irradiations

Energy Technology Data Exchange (ETDEWEB)

Aypar, Umut; Morgan, William F.; Baulch, Janet E.

2011-02-01

Epigenetics, including DNA methylation and microRNA (miRNA) expression, could be the missing link in understanding the delayed, non-targeted effects of radiation including radiationinduced genomic instability (RIGI). This study tests the hypothesis that irradiation induces epigenetic aberrations, which could eventually lead to RIGI, and that the epigenetic aberrations induced by low linear energy transfer (LET) irradiation are different than those induced by high LET irradiations. GM10115 cells were irradiated with low LET x-rays and high LET iron (Fe) ions and evaluated for DNA damage, cell survival and chromosomal instability. The cells were also evaluated for specific locus methylation of nuclear factor-kappa B (NFκB), tumor suppressor in lung cancer 1 (TSLC1) and cadherin 1 (CDH1) gene promoter regions, long interspersed nuclear element 1 (LINE-1) and Alu repeat element methylation, CpG and non-CpG global methylation and miRNA expression levels. Irradiated cells showed increased micronucleus induction and cell killing immediately following exposure, but were chromosomally stable at delayed times post-irradiation. At this same delayed time, alterations in repeat element and global DNA methylation and miRNA expression were observed. Analyses of DNA methylation predominantly showed hypomethylation, however hypermethylation was also observed. MiRNA shown to be altered in expression level after x-ray irradiation are involved in chromatin remodeling and DNA methylation. Different and higher incidence of epigenetic changes were observed after exposure to low LET x-rays than high LET Fe ions even though Fe ions elicited more chromosomal damage and cell killing. This study also shows that the irradiated cells acquire epigenetic changes even though they are chromosomally stable suggesting that epigenetic aberrations may arise in the cell without initiating RIGI.

Characterization of irradiation induced deep and shallow impurities

Science.gov (United States)

Treberspurg, Wolfgang; Bergauer, Thomas; Dragicevic, Marko; Krammer, Manfred; Valentan, Manfred

2013-12-01

Silicon Detectors close to the interaction point of the High Luminosity Large Hardron Collider (HL-LHC) have to withstand a harsh irradiation environment. In order to evaluate the behaviour of shallow and deep defects, induced by neutron irradiation, spreading resistance resistivity measurements and capacitance voltage measurements have been performed. These measurements, deliver information about the profile of shallow impurities after irradiation as well as indications of deep defects in the Space Charge Region (SCR) and the Electrical Neutral Bulk (ENB). By considering the theoretical background of the measurement both kinds of defects can be investigated independently from each other.

Characterization of irradiation induced deep and shallow impurities

Energy Technology Data Exchange (ETDEWEB)

Treberspurg, Wolfgang, E-mail: wolfgang.treberspurg@oeaw.ac.at; Bergauer, Thomas; Dragicevic, Marko; Krammer, Manfred; Valentan, Manfred

2013-12-21

Silicon Detectors close to the interaction point of the High Luminosity Large Hardron Collider (HL-LHC) have to withstand a harsh irradiation environment. In order to evaluate the behaviour of shallow and deep defects, induced by neutron irradiation, spreading resistance resistivity measurements and capacitance voltage measurements have been performed. These measurements, deliver information about the profile of shallow impurities after irradiation as well as indications of deep defects in the Space Charge Region (SCR) and the Electrical Neutral Bulk (ENB). By considering the theoretical background of the measurement both kinds of defects can be investigated independently from each other.

Characterization of irradiation induced deep and shallow impurities

International Nuclear Information System (INIS)

Treberspurg, Wolfgang; Bergauer, Thomas; Dragicevic, Marko; Krammer, Manfred; Valentan, Manfred

2013-01-01

Silicon Detectors close to the interaction point of the High Luminosity Large Hardron Collider (HL-LHC) have to withstand a harsh irradiation environment. In order to evaluate the behaviour of shallow and deep defects, induced by neutron irradiation, spreading resistance resistivity measurements and capacitance voltage measurements have been performed. These measurements, deliver information about the profile of shallow impurities after irradiation as well as indications of deep defects in the Space Charge Region (SCR) and the Electrical Neutral Bulk (ENB). By considering the theoretical background of the measurement both kinds of defects can be investigated independently from each other

Evaluation of induced radioactivity in 10 MeV electron-irradiated spices

Energy Technology Data Exchange (ETDEWEB)

Furuta, Masakazu; Ito, Norio; Mizohata, Akira; Matsunami, Tadao; Katayama, Tadashi; Toratani, Hirokazu (Osaka Prefectural Univ., Sakai (Japan). Research Inst. for Advanced Science and Technology); Takeda, Atsuhiko

1993-10-01

In order to make clear appreciation to induced radioactivity in the irradiated foods, photonuclear reactions which could produce radioactivity at energies up to 10 MeV were listed up from elemental compositions of black pepper, white pepper, red pepper, ginger and turmeric. The samples were irradiated with 10 MeV electron from a linear accelerator to a dose of 100 kGy and radioactivity was measured. Induced radioactivity could not be detected significantly by gamma-ray spectrometry and beta-ray counting in the irradiated samples except for spiked samples which contain some photonuclear target nuclides in the list. From the amount of observed radioactivities of short-lived photonuclear products in the spiked samples and calculation of H[sub 50] according to ICRP Publication 30, it was concluded that the induced radioactivity and its biological effects in the 10 MeV electron-irradiated natural samples were negligible in comparison with natural radioactivity from [sup 40]K contained in the samples. (J.P.N.).

Estimation of irradiation temperature within the irradiation program Rheinsberg

CERN Document Server

Stephan, I; Prokert, F; Scholz, A

2003-01-01

The temperature monitoring within the irradiation programme Rheinsberg II was performed by diamond powder monitors. The method bases on the effect of temperature on the irradiation-induced increase of the diamond lattice constant. The method is described by a Russian code. In order to determine the irradiation temperature, the lattice constant is measured by means of a X-ray diffractometer after irradiation and subsequent isochronic annealing. The kink of the linearized temperature-lattice constant curves provides a value for the irradiation temperature. It has to be corrected according to the local neutron flux. The results of the lattice constant measurements show strong scatter. Furthermore there is a systematic error. The results of temperature monitoring by diamond powder are not satisfying. The most probable value lays within 255 C and 265 C and is near the value estimated from the thermal condition of the irradiation experiments.

Heavy ion irradiation induces autophagy in irradiated C2C12 myoblasts and their bystander cells

International Nuclear Information System (INIS)

Hino, Mizuki; Tajika, Yuki; Hamada, Nobuyuki

2010-01-01

Autophagy is one of the major processes involved in the degradation of intracellular materials. Here, we examined the potential impact of heavy ion irradiation on the induction of autophagy in irradiated C2C12 mouse myoblasts and their non-targeted bystander cells. In irradiated cells, ultrastructural analysis revealed the accumulation of autophagic structures at various stages of autophagy (id est (i.e.) phagophores, autophagosomes and autolysosomes) within 20 min after irradiation. Multivesicular bodies (MVBs) and autolysosomes containing MVBs (amphisomes) were also observed. Heavy ion irradiation increased the staining of microtubule-associated protein 1 light chain 3 and LysoTracker Red (LTR). Such enhanced staining was suppressed by an autophagy inhibitor 3-methyladenine. In addition to irradiated cells, bystander cells were also positive with LTR staining. Altogether, these results suggest that heavy ion irradiation induces autophagy not only in irradiated myoblasts but also in their bystander cells. (author)

Reaction mechanism of hydroxymaleimide induced by γ-irradiation in alcohol solvents

International Nuclear Information System (INIS)

Nakagawa, Seiko

2010-01-01

Methanol and 2-propanol solutions of hydroxymaleimide were irradiated with γ-ray and mechanism of its γ-irradiation-induced reactions was investigated through final-product analyses using high performance liquid chromatography (HPLC) coupled with mass spectroscopy. An addition reaction of a solvent radical toward hydroxymaleimide was dominant among its oxygen-free γ-irradiation-induced reactions in its alcohol solutions while it is known that electron attachment toward hydroxyphthalimide or hydroxysuccinimide is dominant among their γ-irradiation-induced reactions. The radical adduct abstracts hydrogen from solvent molecule to re-produce a solvent radical. Therefore, the degradation efficiency of hydroxymaleimide was more than ten times larger than that of hydroxyphthalimide and hydroxysuccinimide. Dimer was also produced through electron attachment process in the solutions of hydroxymaleimide. In addition, it was found that the degradation efficiency increased with decrease in dose rate. An additional reaction of a solvent radical toward hydroxymaleimide competes with a radical-radical recombination. The latter was reduced, with the former leading to efficient degradation of hydroxymaleimide increased by irradiation at lower dose rate. On the contrary, the production yield of the adduct radical as well as the degradation efficiency of hydroxymaleimide was inhibited in the presence of oxygen.

Reaction mechanism of hydroxymaleimide induced by γ-irradiation in alcohol solvents

International Nuclear Information System (INIS)

Nakagawa, Seiko

2010-01-01

Methanol and 2-propanol solutions of hydroxymaleimide were irradiated with γ-ray and mechanism of its γ-irradiation-induced reactions was investigated through final-product analyses using high performance liquid chromatography (HPLC) coupled with mass spectroscopy. An addition reaction of a solvent radical toward hydroxymaleimide was dominant among its oxygen-free γ-irradiation-induced reactions in its alcohol solutions while it is known that electron attachment toward hydroxyphthalimide or hydroxysuccinimide is dominant among their γ-irradiation-induced reactions. The radical adduct abstracts hydrogen from solvent molecule to re-produce a solvent radical. Therefore, the degradation efficiency of hydroxymaleimide was more than 10 times larger than that of hydroxyphthalimide and hydroxysuccinimide. Dimer was also produced through electron attachment process in the solutions of hydroxymaleimide. In addition, it was found that the degradation efficiency increased with decreasing the dose rate. An addition reaction of a solvent radical toward hydroxymaleimide competes with a radical-radical recombination. The latter was reduced and the former leading to efficient degradation of hydroxymaleimide increased by irradiation at lower dose rate. On the contrary, the production yield of the adduct radical as well as the degradation efficiency of hydroxymaleimide was inhibited in the presence of oxygen.

Roles of acid sphingomyelinase activation in neuronal cells apoptosis induced by microwave irradiation

International Nuclear Information System (INIS)

Zhang Lei; Xu Shangcheng; Zhang Guangbin; Yu Zhengping

2009-01-01

The present study is to examine the effect of microwave on acid sphingomyelinase (ASM) activity and expression, and to explore the role of ASM activation in neuronal cells apoptosis induced by microwave irradiation. Primary cultured hippocampal neurons were irradiated by 30 W/cm 2 microwave for 10 min, and ASM activity assay was used to investigate ASM activity alteration. RT-PCR and western blot were used to detect ASM mRNA and protein expression respectively. Apoptosis was observed by Hoechst 33342 fluorescence staining. ASM specific inhibitor imipramine was applied to inhibit ASM activation. It has been found that apoptosis rate of primary cultured hippocampal neurons increased significantly after microwave irradiation. ASM was activated while ASM mRNA and protein expression were upregulated in neurons after microwave irradiation. Pretreatment with imipramine could reverse neuronal apoptosis induced by microwave irradiation. Results show that microwave irradiation causes increment of ASM activation and expression and ASM activation is involved in microwave induced neuronal apoptosis. (authors)

Irradiation strongly reduces tumorigenesis of human induced pluripotent stem cells

International Nuclear Information System (INIS)

Inui, Shoki; Minami, Kazumasa; Ito, Emiko; Imaizumi, Hiromasa; Mori, Seiji; Koizumi, Masahiko; Fukushima, Satsuki; Miyagawa, Shigeru; Sawa, Yoshiki; Matsuura, Nariaki

2017-01-01

Induced pluripotent stem (iPS) cells have demonstrated they can undergo self-renewal, attain pluripotency, and differentiate into various types of functional cells. In clinical transplantation of iPS cells, however, a major problem is the prevention of tumorigenesis. We speculated that tumor formation could be inhibited by means of irradiation. Since the main purpose of this study was to explore the prevention of tumor formation in human iPS (hiPS) cells, we tested the effects of irradiation on tumor-associated factors such as radiosensitivity, pluripotency and cell death in hiPS cells. The irradiated hiPS cells showed much higher radiosensitivity, because the survival fraction of hiPS cells irradiated with 2 Gy was < 10%, and there was no change of pluripotency. Irradiation with 2 and 4 Gy caused substantial cell death, which was mostly the result of apoptosis. Irradiation with 2 Gy was detrimental enough to cause loss of proliferation capability and trigger substantial cell death in vitro. The hiPS cells irradiated with 2 Gy were injected into NOG mice (NOD/Shi-scid, IL-2 Rγnull) for the analysis of tumor formation. The group of mice into which hiPS cells irradiated with 2 Gy was transplanted showed significant suppression of tumor formation in comparison with that of the group into which non-irradiated hiPS cells were transplanted. It can be presumed that this diminished rate of tumor formation was due to loss of proliferation and cell death caused by irradiation. Our findings suggest that tumor formation following cell therapy or organ transplantation induced by hiPS cells may be prevented by irradiation.

Local regulation of haemopoietic stem cell proliferation in mice following irradiation

International Nuclear Information System (INIS)

Ali, A.M.; Riches, A.C.; Wright, E.G.

1989-01-01

Changes in the kinetic state of pluripotent haemopoietic spleen colony forming cells (CFU-S) and of the CFU-S proliferation stimulator have been studied following whole-body X-irradiation. Rapid recruitment of CFU-S into cell cycle by 30 min after irradiation was observed following low doses (0.5 Gy) but a delay of 6 h occurred after higher doses (1.5 and 4.5 Gy). These changes in proliferative state correlated with the presence of the CFU-S proliferation stimulator. CFU-S irradiated in vitro in bone marrow plugs were also recruited into cycle illustrating directly the local nature of the feedback mechanism. CFU-S removed from 1.5 Gy irradiated recipients at a time when they were not in cycle were not responsive to the CFU-S proliferation stimulator. The CFU-S proliferation stimulator was produced by Ia positive cells in the irradiated bone marrow. The regulation changes occurring shortly after irradiation cannot simply be controlled by the size of the CFU-S compartment. (author)

Renal effects of renal x irradiation and induced autoallergic glomerulonephritis

International Nuclear Information System (INIS)

Rappaport, D.S.; Casarett, G.W.

1979-01-01

This study was conducted to determine what influence a single large x-ray exposure of kidney has on the development and course of an experimental autoallergic glomerulonephritis (EAG) in rats. EAG was induced in female Sprague-Dawley rats by immunization with Bordetella pertussis vaccine and homogenate of homologous kidney tissue and Freund's complete adjuvant. Progressive arteriolonephrosclerosis (ANS) was observed in right (irradiated) kidneys following unilateral renal irradiation (1500 rad). Rats were either immunized, sham-immunized, irradiated, sham-irradiated, or both immunized and irradiated. Light and immunofluorescent microscopic observation, urine protein content, and kidney weights were evaluated. In immunized-irradiated animals the effects of irradiation and immunization were largely additive. Immunization did not considerably influence the development and course of ANS and irradiation did not considerably influence the development and course of EAG

Structural changes and tribological performance of thermosetting polyimide induced by proton and electron irradiation

International Nuclear Information System (INIS)

Lv, Mei; Wang, Yanming; Wang, Qihua; Wang, Tingmei; Liang, Yongmin

2015-01-01

The structural changes and tribological performance of thermosetting polyimide were investigated by electron, proton or both combined irradiations at 25 keV in a ground-based simulation facility. Three forms of irradiations could lead to the formation of the carbonized layer on the polymer surface that could increase the hardness and adhesive force of the material. Proton irradiation induced more extensive changes in structure and friction behavior than electron irradiation by reason of the higher linear energy transfer value, and combined irradiation resulted in the largest impact, but which was less than the sum of the radiation effects of electron and proton. Moreover, the experimental results indicated that the changes in friction behavior are closely related with the carbonized layer, which was easily worn out in friction process and could introduce a shift from adhesion wear to three-body abrasive wear that reduced the wear rate and the friction coefficient. The friction process of irradiated samples could be divided into the initial stage and the steady stage. Three forms of irradiations all induced the high friction coefficient in the initial stage and the low friction coefficient in the steady stage, and the wear rate of the irradiated samples decreased in the order: electron irradiation>proton irradiation>combined irradiation. - Highlights: • Proton irradiation induced more extensive changes in structure and friction behavior than electron irradiation. • The effect of combined irradiation was less than that of the sum of electron and proton irradiation. • Three forms of irradiations all induced the high initial friction coefficient and the low steady-stage friction coefficient. • The initial friction stage means a fast-wearing adhesive process while the steady-state of the system is a three-body abrasion

Irradiation induced precipitation: a thermodynamical approach

International Nuclear Information System (INIS)

Bocquet, J.-L.; Martin, Georges.

1979-02-01

A binary alloy (A, B) under steady state irradiation is considered as a ternary alloy (A, B, defects) in constrained equilibrium (the constraint represented by the irradiation consists in maintaining a given supersaturation of point defects). All possible two-body interactions (attractive, repulsive) have been checked between the solvent A, the solute B, and the defects C. The conditions of an irradiation corresponds to a low point-defect concentration; the only cases of interest are those where such a low concentration makes new phases precipitate, which are richer in solute than the initial solid-solution. Radiation induced precipitation is expected to occur under the following necessary conditions: - when the binary alloy (A, B) shows ordering or is ideal, a necessary condition is that the binary solute-defects must show ordering. - when the binary alloy (A, B) shows clustering, a necessary condition is that the temperature must be close to the critical mixing temperature Tsub(AB)sup(D). The physical significance of these conditions is discussed [fr

Structural and defects induced phenomena in γ-rays irradiated 6H-SiC

International Nuclear Information System (INIS)

Sibuyi, P.; Ngom, B.D.; Kotsedi, L.

2016-01-01

Damages and/or defects induced by γ-rays irradiation on 6H-SiC single crystals in channeled configuration towards 〈006〉/〈0012〉 crystallographic directions are reported in the range of 0–1200 kGy. Atomic force microscopy, X-rays diffraction, Raman and photoluminescence investigations were used to obtain a comprehensive set of informations on the nature and population distribution of the induced defects. Primarily, there was no carbon clusterization upon γ-rays irradiation and hence no formation of others SiC polytypes. In contrast, the γ-rays irradiation has induced an increase of the surface roughness at higher doses, which indicates a structural degradation. Larger doses induced an emergence of deeper shallow traps at energies greater than 350 meV below the bandgap. - Highlights: • No formation of others SiC polytypes. • The gamma rays irradiation has induced a slight surface amorphization. • A re-crystallization at lower and higher doses is noticed. • Larger doses induced a substantial internal stress.

Relaxation behavior and dose dependence of radiation induced radicals in irradiated mango

International Nuclear Information System (INIS)

Kameya, Hiromi; Kakita, Daisuke; Kaimori, Yoshihiko; Ukai, Mitsuko; Kikuchi, Masahiro; Kobayashi, Yasuhiko; Shimoyama, Yuhei

2010-01-01

Mangoes are imported to Japan after treated with hot water. Recently, irradiated mangoes imported to U. S. are widely used. This paper reports on the ESR method for analyzing the radiation induced radicals of irradiated mangoes. Upon the γ ray irradiation, a strong single peak in the flesh and skin of mangoes was observed at g=2.004. This singlet peak may be attributed to organic free radicals. The ESR spectra of the flesh and skin of mangoes showed the radiation induced radicals due to cellulose by irradiation over 12 kGy. The relaxation times (T 1 and T 2 ) of the singlet signal were calculated. T 2 showed dose response according to increasing the irradiation dose levels, while T 1 was almost constant. The value of (T 1 T 2 ) 1/2 showed the dependence of irradiation dose level. (author)

γ - irradiation induced effect on the optical parameters of Cu10 Se90 thin films

International Nuclear Information System (INIS)

Abu EL-Fadl, A.; Hafiz, M. M.; Aashour, A.S.; Wakaad, M.M.

2007-01-01

The optical constants of Cu 10 SE 90 Chalcogenide films successfully deposited by evaporation coating technique have been measured. The absorption coefficient (a) for the as-deposited or after being γ-irradiation at various doses have been computed in the spectral wavelength range 400-900 nm from the transmittance (T) and reflectance (R) measurements of normally-incident light. Both irradiated and as-prepared films showed direct transition. The direct optical band gaps of the films were found to decrease from 2.017 for as prepared to 1.941 eV for γ-irradiation at 190 kGy doses. The width of the tails of localized states E e were calculated and found to be increasing after γ-irradiation. The effects of the γ-irradiation on the refractive index n and extinction coefficient k were studied. Other optical parameters (ε I , ε 2 were calculated at different γ-irradiation doses the obtained values of both ε 1 and ε 2 were found to be incident light and γ-doses dependent. The effect of γ-irradiation on the high-frequency dielectric constant (ε ∞ ) and carrier concentration (N/m * ) is also studied. The change on the degree of disorder as will as the radiation-induced defect changes applied to explain the radiation effects on nature of optical properties Cu 10 SE 90 glasses

Evaluation of induced radioactivity in 10 MeV-electron irradiated spices, (1)

International Nuclear Information System (INIS)

Furuta, Masakazu; Katayama, Tadashi; Ito, Norio; Mizohata, Akira; Matsunami, Tadao; Shibata, Setsuko; Toratani, Hirokazu; Takeda, Atsuhiko.

1994-01-01

Black pepper, white pepper, red pepper, ginger and turmeric were irradiated with 10 MeV electrons from a linear accelerator to a dose of 100 kGy and radioactivity was measured in order to estimate induced radioactivity in the irradiated foods. Induced radioactivity could not be detected significantly by γ-ray spectrometry in the irradiated samples except for spiked samples which contain some photonuclear target nuclides in the list of photonuclear reactions which could produce radioactivity below 10 MeV. From the amount of observed radioactivities of short-lived photonuclear products in the spiked samples and calculation of H 50 according to ICRP Publication 30, it was concluded that the induced radioactivity and its biological effects in the 10 MeV electron-irradiated natural samples were negligible in comparison with natural radioactivity from 40 K contained in the samples. (author)

Effects of local and whole body irradiation on appearance of osteoclasts during wound healing of tooth extraction sockets in rats

International Nuclear Information System (INIS)

Hosokawa, Yoichiro; Sakakura, Yasunori; Tanaka, Likinobu; Okumura, Kazuhiko; Yajima, Toshihiko; Kaneko, Masayuki

2007-01-01

We examined effects of local and whole body irradiation before tooth extraction on appearance and differentiation of osteoclasts in the alveolar bone of rat maxillary first molars. Wistar rats weighting 100 g were divided into three groups: non-irradiation group, local irradiation group, and whole body irradiation group. In the local irradiation group, a field made with lead blocks was placed over the maxillary left first molar tooth. In the whole body irradiation group, the animals were irradiated in cages. Both groups were irradiated at 8 Gy. The number of osteoclasts around the interradicular alveolar bone showed chronological changes common to non-irradiated and irradiated animals. Several osteoclasts appeared one day after tooth extraction, and the maximal peak was observed 3 days after extraction. Local irradiation had no difference from non-irradiated controls. In animals receiving whole body irradiation, tooth extraction one day after irradiation caused smaller number of osteoclasts than that 7 day after irradiation during the experimental period. Whole body-irradiated rats had small osteoclasts with only a few nuclei and narrow resorption lacunae, indicating deficiency of radioresistant osteoclast precursor cells. Injection of intact bone marrow cells to whole body-irradiated animals immediately after tooth extraction recovered to some content the number of osteoclasts. These findings suggest that bone resorption in the wound healing of alveolar socket requires radioresistant, postmitotic osteoclast precursor cells from hematopoietic organs, but not from local sources around the alveolar socket, at the initial phase of wound healing. (author)

Effects of local and whole body irradiation on appearance of osteoclasts during wound healing of tooth extraction sockets in rats.

Science.gov (United States)

Hosokawa, Yoichiro; Sakakura, Yasunori; Tanaka, Likinobu; Okumura, Kazuhiko; Yajima, Toshihiko; Kaneko, Masayuki

2007-07-01

We examined effects of local and whole body irradiation before tooth extraction on appearance and differentiation of osteoclasts in the alveolar bone of rat maxillary first molars. Wistar rats weighting 100 g were divided into three groups: non-irradiation group, local irradiation group, and whole body irradiation group. In the local irradiation group, a field made with lead blocks was placed over the maxillary left first molar tooth. In the whole body irradiation group, the animals were irradiated in cages. Both groups were irradiated at 8 Gy. The number of osteoclasts around the interradicular alveolar bone showed chronological changes common to non-irradiated and irradiated animals. Several osteoclasts appeared one day after tooth extraction, and the maximal peak was observed 3 days after extraction. Local irradiation had no difference from non-irradiated controls. In animals receiving whole body irradiation, tooth extraction one day after irradiation caused smaller number of osteoclasts than that 7 day after irradiation during the experimental period. Whole body-irradiated rats had small osteoclasts with only a few nuclei and narrow resorption lacunae, indicating deficiency of radioresistant osteoclast precursor cells. Injection of intact bone marrow cells to whole body-irradiated animals immediately after tooth extraction recovered to some content the number of osteoclasts. These findings suggest that bone resorption in the wound healing of alveolar socket requires radioresistant, postmitotic osteoclast precursor cells from hematopoietic organs, but not from local sources around the alveolar socket, at the initial phase of wound healing.

Analysis of irradiation processes for laser-induced periodic surface structures

NARCIS (Netherlands)

Eichstädt, J.; Huis In 't Veld, A.J.

2013-01-01

The influence of errors on the irradiation process for laser-induced periodic surface structures (LIPSS) was studied theoretically with energy density simulations. Therefore an irradiation model has been extended by a selection of technical variations. The influence of errors has been found in a

The characteristics and mechanism of apoptosis induced by internal irradiation

International Nuclear Information System (INIS)

Hong Chengjiao; Zhang Junning; Zhu Shoupeng

2001-01-01

Apoptosis in tumor cells induced by radionuclides is likely the most effective way to cure cancer. In order to explore the possibility in clinic application, the characteristics and mechanism of apoptosis induced by internal irradiation were investigated. The apoptosis and expressions of bcl-2mRNA, bcl-2 and bax of K 562 cells following internal exposure with different accumulated absorbed doses of strontium-89 were studied. 6 h after irradiation, the characteristics of apoptosis and necrosis appeared in K 562 cells. The apoptosis and necrosis enhanced with the prolongation of internally contaminated time at 6 h, 9 h, 12 h, 24 h and 48 h. The expressions of bcl-2mRNA decreased at 12 h, most remarkably at 24 h. The expressions of bcl-2 decreased after irradiation whereas bax had no obvious changes. The results suggest that the apoptosis induced by internal exposure may be regulated by lower expressions of bcl-2mRNA and bcl-2, lower bcl-2/bax value

The irradiation induced creep of graphite under accelerated damage produced by boron doping

International Nuclear Information System (INIS)

Brocklehurst, J.E.

1975-01-01

The presence of boron enhances fast neutron irradiation damage in graphite by providing nucleation sites for interstitial loop formation. Doping with 11 B casues an increase in the irradiation induced macroscopic dimensional changes, which have been shown to result from an acceleration in the differential crystal growth rate for a given carbon atom displacement rate. Models of irradiation induced creep in graphite have centred around those in which creep is induced by internal stresses due to the anisotopic crystal growth, and those in which creep is activated by atomic displacements. A creep test on boron doped graphite has been performed in an attempt to establish which of these mechanisms is the determining factor. An isotropic nuclear graphite was doped to a 11 B concentration of 0.27 wt.%. The irradiation induced volume shrinkage rate at 750 0 C increased by a factor of 3 over that of the virgin graphite, in agreement with predictions from the earlier work, but the total creep strains were comparable in both doped and virgin samples. This observation supports the view that irradiation induced creep is dependent only on the carbon atom displacement rate and not on the internal stress level determined by the differential crystal growth rate. The implications of this result on the irradiation behaviour of graphite containing significant concentrations of boron are briefly discussed. (author)

The Role of DNA Methylation Changes in Radiation-Induced Transgenerational Genomic Instability and Bystander Effects in cranial irradiated Mice

Science.gov (United States)

Zhang, Meng; Sun, Yeqing; Gao, Yinglong; Zhang, Baodong

Heavy-ion radiation could lead to genome instability in the germline, and therefore to transgenerational genome and epigenome instability in offspring of exposed males. The exact mechanisms of radiation-induced genome instability in directly exposed and in bystander organ remain obscure, yet accumulating evidence points to the role of DNA methylation changes in genome instability development. The potential of localized body-part exposures to affect the germline and thus induce genome and epigenome changes in the progeny has not been studied. To investigate whether or not the paternal cranial irradiation can exert deleterious changes in the protected germline and the offsprings, we studied the alteration of DNA methylation in the shielded testes tissue. Here we report that the localized paternal cranial irradiation results in a significant altered DNA methylation in sperm cells and leads to a profound epigenetic dysregulation in the unexposed progeny conceived 3 months after paternal exposure. The possible molecular mechanisms and biological consequences of the observed changes are discussed. Keywords: Heavy-ion radiation; Transgenerational effect; Genomic Instability Bystander Effects; DNA methylation.

Effect of Bifidobacterium breve B-3 on skin photoaging induced by chronic UV irradiation in mice.

Science.gov (United States)

Satoh, T; Murata, M; Iwabuchi, N; Odamaki, T; Wakabayashi, H; Yamauchi, K; Abe, F; Xiao, J Z

2015-01-01

Probiotics have been shown to have a preventative effect on skin photoaging induced by short term UV irradiation, however, the underlying mechanisms and the effect of probiotics on skin photoaging induced by chronic UV irradiation remain unclear. In this study, we investigated the effect of Bifidobacterium breve B-3 on skin photoaging induced by chronic UV irradiation in hairless mice. Mice were irradiated with UVB three times weekly and orally administered B. breve B-3 (2×10(9) cfu/mouse /day) for 7 weeks. Nonirradiated mice and UVB-irradiated mice without probiotic treatment were used as controls. B. breve B-3 significantly suppressed the changes of transepidermal water loss, skin hydration, epidermal thickening and attenuated the damage to the tight junction structure and basement membrane induced by chronic UVB irradiation. Administration of B. breve B-3 tended to suppress the UV-induced interleukin-1β production in skin (P=0.09). These results suggest that B. breve B-3 could potentially be used to prevent photoaging induced by chronic UV irradiation.

Local structure and defects in ion irradiated KTaO3

Science.gov (United States)

Zhang, F. X.; Xi, J.; Zhang, Y.; Tong, Yang; Xue, H.; Huang, R.; Trautmann, C.; Weber, W. J.

2018-04-01

The modification of the local structure in cubic perovskite KTaO3 irradiated with 3 MeV and 1.1 GeV Au ions is studied by Raman and x-ray absorption spectroscopy, complemented by density functional theory (DFT) calculations. In the case of irradiation with 3 MeV Au ions where displacement cascade processes are dominant, the Ta L3-edge x-ray absorption measurements suggest that a peak corresponding to the Ta-O bonds in the TaO6 octahedra splits, which is attributed to the formation of TaK antisite defects that are coupled with oxygen vacancies, V O. This finding is consistent with the DFT calculations. Under irradiation with 1.1 GeV ions, the intense ionization and electronic energy deposition lead to a blue shift and an intensity reduction of active Raman bands. In the case of sequential irradiations, extended x-ray absorption fine structure measurements reveal a decrease in concentration of coupled TaK-V O defects under subsequent irradiation with 1.1 GeV Au ions.

Simultaneous PLK1 inhibition improves local tumour control after fractionated irradiation

International Nuclear Information System (INIS)

Krause, Mechthild; Kummer, Berit; Deparade, Andre; Eicheler, Wolfgang; Pfitzmann, Dorothee; Yaromina, Ala; Kunz-Schughart, Leoni A.

2013-01-01

Purpose: Polo-like kinase 1 (PLK1) plays an important role in mitotic progression, is frequently overexpressed and associated with a poor prognosis of cancer patients, thus providing a promising target in anticancer treatment. Aim of the current project was to evaluate the effect of the novel PLK1 inhibitor BI 6727 in combination with irradiation. Material and methods: In vitro proliferation and radiation cell survival assays as well as in vivo local tumour control assays after single treatment and combined radiation and drug application were carried out using the squamous cell carcinoma models A431 and FaDu. In addition, cell cycle phases were monitored in vitro and in vivo. Results: BI 6727 showed a dose-dependent antiproliferative effect and an increase in the mitotic fraction. BI 6727 alone reduced clonogenic cell survival, while radiosensitivity in vitro (SF2) and in vivo (single-dose TCD 50 under clamped hypoxia) was not affected. In contrast, local tumour control was significantly improved after application of BI 6727 simultaneously to fractionated irradiation (A431: TCD 50 = 60.5 Gy [95% C.I. 57; 63] after IR alone and <30 Gy after combined treatment; FaDu: 49.5 Gy [43; 56 Gy] versus 32.9 Gy [26; 40]). Conclusions: Despite the lack of direct cellular radiosensitisation, PLK1 inhibition with BI 6727 during fractionated irradiation significantly improves local tumour control when compared to irradiation alone. This result is likely explained by a considerable effect on cell cycle and an independent cytotoxic potential of BI 6727

Participation of lymphocytes in hemopoiesis regeneration under local irradiation of the body

International Nuclear Information System (INIS)

Gol'dberg, E.D.; Dygaj, A.M.

1982-01-01

Lymphocyte participation in regulation of a pool of stem blood-producing cells using a model of local irradiation of bone marrow was studied. Right pelvic limb of BALB/c strain mice was exposed to local X-radiation at a dose of 7.0 Gy. During different periods after the irradiation the animals were killed and the total number of nucleus-containing cells in thymus, spleen, bone marrow from irradiated and screened femurs were counted. Smears of bone marrow were used to calculate myelogram. To study thymocyte effect on postradiation regeneration of hemopoesis, each of thymectomized mice were injected intravenously 4x10 7 viable thymocytes. Processes of the postradiation regeneration of hemopoesis were specially investigated in animals against the background of intraperitoneal injection of antithymocytic heterologous serum. The population of stem blood-producing cells of bone marrow was studied by the method of exogenic cloning in the body of syngenic recipient lethally irradiated (7.5 Gy). It is shown that during the period before active recovery of hemopoesis observed is the selective accumulation of lymphocytes of predominantly thymus origin only in irradiated blood-producing tissue. T lymphocytes stimulated colony-forming activity of bone marrow and accelerated the postradiation regeneration of hemopoesis

Elemental process of amorphization induced by electron irradiation in Si

International Nuclear Information System (INIS)

Yamasaki, Jun; Takeda, Seiji; Tsuda, Kenji

2002-01-01

We recently found that amorphization is induced in Si by electron irradiation. Examining the amorphization systematically, we have established the diagram of steady states under electron irradiation, either amorphous Si (a-Si) or crystalline Si (c-Si) as a function of incident electron energy, electron dose, and irradiation temperature. Utilizing transmission electron microscopy, electron energy filtered diffraction and electron energy-loss spectroscopy, we have characterized the atomic structure, the electronic structure, and the thermal stability of a-Si induced by electron irradiation. Based on the experimental data, we have also concluded that the amorphization is caused by the accumulation of not point defects but small cascade damages. Analyzing the change in the intensity of halo diffraction rings during amorphization, we have clarified that the smallest cascade damage that contributes to amorphization includes only about four Si atoms. This presumably supports the amorphization mechanism that four self-interstitial atoms form the quasistable structure I4 in c-Si and it becomes an amorphous embryo

Irradiation-induced mutation experiments with eiploid and tetraploid tomato plants

International Nuclear Information System (INIS)

Boda, J.

1979-01-01

Tomato mutation experiments are described. The tomatoes used in the experiment were the diploid Reziszta and its autotetraploid variety. The experimental plants were exposed to an irradiation of 5000 rsd for 1-2 days, and after transplantation into the gamma field, to chronic irradiation during the whole growing season. The chronic treatment heavily reduced fertility in the generations of tetraploid tomato plants. Recurrent treatment of tetraploid led to further deterioration in fertility. Several berries were formed with few seeds or with no seeds at all. After three irradiations, the chlorophyll mutation frequency increased in the diploid and tetraploid tomato plants. For diploids, treatment applied at the seedling stage gave a lower chlorophyll mutation frequency. With tetraploids the same treatment induced similar chlorophyll mutation frequency. As regards to phenotypic variability of quantitative characteristics in diploid and tetraploid tomatoes, the single and repeated chronic irradiation induced no increase in the variability of properties like flowering time, weight, height etc. (author)

An ESR study of radicals induced in irradiated fresh mango

International Nuclear Information System (INIS)

Kikuchi, Masahiro; Hussain, Mohammed S.; Morishita, Norio; Kobayashi, Yasuhiko; Ukai, Mitsuko; Shimoyama, Yuhei

2009-01-01

An electron spin resonance (ESR) spectroscopic study was performed on the radicals induced irradiated fresh mangoes. Fresh Philippine mangoes were irradiated by the γ-rays, lyophilized and powdered. The ESR spectrum of the dry specimen showed a strong main peak at g=2.004 and a pair of peaks at both magnetic fields of the main peak. The main peak detected from flesh and skin specimens faded away in a few days after the irradiation. On the other hand, the side peaks showed a well-defined dose response even 9 days after the irradiation. The side-peak is a useful mean to define the irradiation on fresh mangoes. (author)

Re-irradiation after salvage mastectomy for local recurrence after a conservative treatment: a retrospective analysis of twenty patients (Nancy: 1988-2001); Re-irradiation parietale apres mastectomie de rattrapage pour recidive d'un cancer du sein apres traitement conservateur: etude retrospective sur 20 patientes (Nancy: 1988-2001)

Energy Technology Data Exchange (ETDEWEB)

Racadot, S.; Marchal, C.; Charra-Brunaud, C.; Peiffert, D.; Bey, P. [Centre Alexis-Vautrin, Service de Radiotherapie, 54 - Vandoeuvre-les-Nancy (France); Verhaeghe, J.L. [Centre Alexis-Vautrin, Service de Chirurgie, 54 - Vandoeuvre-les-Nancy (France)

2003-12-01

Purpose. - To retrospectively assess the efficacy of post-mastectomy re-irradiation for local relapse of breast cancer. Patients and methods. - Twenty patients, initially treated by conservative surgery and radiotherapy (50 Gy in 25 fractions over 5 weeks) were treated from 1998 to 2001 for a local relapse by salvage mastectomy and re-irradiation (either electron or photon beams). Mean age was 53 years (31-71). Reasons for re-irradiation were that the local relapses were inflammatory (4 pts), multifocal (5 pts), cutaneous (5 pts), involved the nipple (3 pts) or because the surgical margins (either muscle or skin) were involved (3 pts). The median dose of re-irradiation was 45 Gy (33-65) in 15 fractions over 33 days. Mean follow-up was 48 months (5-97). Results. - Fifteen patients remained free of a second local recurrence and 10 were still alive, without metastasis. Neither the dose of re-irradiation nor the irradiated surfaces were prognostic factors of local control (P = 0.877 and P = 0.424). Five patients developed radiation-induced pneumonitis without functional respiratory impairment. The incidence of pneumonitis seemed to be related to the biological dose of re-irradiation (P = 0.037). Other late complications occurred such as pigmentation changes (12 pts), telangiectasia (8 pts), chondritis (2 pts), parietal fibrosis (7 pts), rib fractures (4 pts), severe pain (11 pts) and lymphedema (2 pts). The increase in biological equivalent dose was highly statistically linked with the occurrence of disabling pain (P = 0.0123). Conclusion. - Parietal re-irradiation achieves good and lasting local control with an acceptable rate of acute complications but with a risk of disabling late sequelae such as severe pain. (author)

γIrradiation induced formation of PCB-solvent adducts in aliphatic solvents

International Nuclear Information System (INIS)

Lepine, F.; Milot, S.; Gagne, N.

1990-01-01

γIrradiation induced formation of PCB-solvent adducts was investigated as a model for PCB residues in irradiated food. Formation of cyclohexyl adducts of PCBs was found to be significant when pure PCB congeners and Aroclor mixture were irradiated in cyclohexane and cyclohexene. Reaction pathways were investigated, and the effects of oxygen and electron scavenger were studied

Effect of irradiation on the temporomandibular joint in streptozotocin-induced diabetic rat

Energy Technology Data Exchange (ETDEWEB)

Ahn, Ki Dong; Hwang, Eui Hwan; Lee, Sang Rae [Kyunghee University College of Medicine, Seoul (Korea, Republic of)

2004-06-15

To investigate the histopathological changes in the temporomandibular joint in streptozotocin-induced diabetic rat following irradiation. Sprague-Dawley rats weighing about 250 gm were divided into three groups: control, diabetic, and diabetic-irradiated groups. Diabetes mellitus was induced in the rats by injecting streptozotocin. Rats in the control group were injected with citrate buffer only. After 5 days, the head and neck region of the rats in diabetic-irradiated group were irradiated with single absorbed dose of 10 Gy. The rats were killed at 1, 3, 7, 14, 21, and 28 days after irradiation. The specimen including the temporomandibular joint were sectioned and observed using a histopathological method. In the diabetic group, severe bone resorption in the mandibular condyle was observed throughout the period of experiment. Necrosis of bone marrow and trabeculae was observed at 28 days after diabetic state. Atrophy and fibrosis in the retrodiscal tissue was gradually progressed during the time of the experiment. In the diabetic-irradiated group, severe bone resorption in the mandibular condyle was observed during the early experimental phases, but regeneration of bone marrow was initiated at 14 days after diabetic state and irradiation. Also, calcification of abnormal trabeculae was observed at 28 days after diabetic state and irradiation. The retrodiscal tissue was degenerated in the early experimental phases, but it had been gradually regenerated during the experimental time. This experiment suggests that bone resorption and degeneration in the mandibular condyle are caused by the induction of diabetes, and abnormal bone formation is induced after irradiation in diabetic state.

Effect of irradiation on the temporomandibular joint in streptozotocin-induced diabetic rat

International Nuclear Information System (INIS)

Ahn, Ki Dong; Hwang, Eui Hwan; Lee, Sang Rae

2004-01-01

To investigate the histopathological changes in the temporomandibular joint in streptozotocin-induced diabetic rat following irradiation. Sprague-Dawley rats weighing about 250 gm were divided into three groups: control, diabetic, and diabetic-irradiated groups. Diabetes mellitus was induced in the rats by injecting streptozotocin. Rats in the control group were injected with citrate buffer only. After 5 days, the head and neck region of the rats in diabetic-irradiated group were irradiated with single absorbed dose of 10 Gy. The rats were killed at 1, 3, 7, 14, 21, and 28 days after irradiation. The specimen including the temporomandibular joint were sectioned and observed using a histopathological method. In the diabetic group, severe bone resorption in the mandibular condyle was observed throughout the period of experiment. Necrosis of bone marrow and trabeculae was observed at 28 days after diabetic state. Atrophy and fibrosis in the retrodiscal tissue was gradually progressed during the time of the experiment. In the diabetic-irradiated group, severe bone resorption in the mandibular condyle was observed during the early experimental phases, but regeneration of bone marrow was initiated at 14 days after diabetic state and irradiation. Also, calcification of abnormal trabeculae was observed at 28 days after diabetic state and irradiation. The retrodiscal tissue was degenerated in the early experimental phases, but it had been gradually regenerated during the experimental time. This experiment suggests that bone resorption and degeneration in the mandibular condyle are caused by the induction of diabetes, and abnormal bone formation is induced after irradiation in diabetic state.

The Use of Re-irradiation in Locally Recurrent, Non-metastatic Rectal Cancer.

Science.gov (United States)

Susko, Matthew; Lee, Jason; Salama, Joseph; Thomas, Samantha; Uronis, Hope; Hsu, David; Migaly, John; Willett, Christopher; Czito, Brian; Palta, Manisha

2016-10-01

The optimal approach to patients with locally recurrent, non-metastatic rectal cancer is unclear. This study evaluates the outcomes and toxicity associated with pelvic re-irradiation. Patients undergoing re-irradiation for locally recurrent, non-metastatic, rectal cancer between 2000 and 2014 were identified. Acute and late toxicities were assessed using common terminology criteria for adverse events version 4.0. Disease-related endpoints included palliation of local symptoms, surgical outcomes, and local progression-free survival (PFS), distant PFS and overall survival (OS) using the Kaplan-Meier method. Thirty-three patients met the criteria for inclusion in this study. Two (6 %) experienced early grade 3+ toxicity and seven (21 %) experienced late grade 3+ toxicity. Twenty-three patients presented with symptomatic local recurrence and 18 (78 %) reported symptomatic relief. Median local PFS was 8.7 (95 % CI 3.8-15.2) months, with a 2-year rate of 15.7 % (4.1-34.2), and median time to distant progression was 4.4 (2.2-33.3) months, with a 2-year distant PFS rate of 38.9 % (20.1-57.3). Median OS time for patients was 23.1 (11.1-33.0) months. Of the 14 patients who underwent surgery, median survival was 32.3 (13.8-48.0) months compared with 13.3 (2.2-33.0) months in patients not undergoing surgery (p = 0.10). A margin-negative (R0) resection was achieved in 10 (71 %) of the surgeries. Radiation treatment modality (intensity-modulated radiation therapy, three-dimensional conformal radiotherapy, intraoperative radiation therapy) did not influence local or distant PFS or OS. Re-irradiation is a beneficial treatment modality for the management of locally recurrent, non-metastatic rectal cancer. It is associated with symptom improvement, low rates of toxicity, and similar benefits among radiation modalities.

Aspects of ion irradiations to study localized deformation in austenitic stainless steels

Energy Technology Data Exchange (ETDEWEB)

Jiao, Zhijie, E-mail: zjiao@umich.edu [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI 48109 (United States); Was, Gary [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI 48109 (United States); Miura, Terumitsu; Fukuya, Koji [Institute of Nuclear Safety System (INSS) (Japan)

2014-09-15

The effect of irradiation depth on localized deformation in strained SUS304 and SUS316 was assessed by irradiation to various doses using different energies of Fe{sup ++} and protons. The average height and spacing of slip steps formed on the surfaces after 2% plastic strain in 300 °C argon were characterized using AFM and SEM. The step height and spacing were nearly unchanged for irradiation depth greater than 1/3 of the average grain size. 2.8 MeV Fe{sup ++} irradiation, with an irradiation depth of <1 μm, resulted in slightly larger step spacing compared to the unirradiated samples but it was much smaller compared to that in proton-irradiated samples with much greater irradiation depths. Step height and spacing also appeared to be affected by the grain size as they were nearly double in magnitude for 30 μm compared to 14 μm grain sizes in SUS304.

Localized irradiation of mouse legs using an image-guided robotic linear accelerator.

Science.gov (United States)

Kufeld, Markus; Escobar, Helena; Marg, Andreas; Pasemann, Diana; Budach, Volker; Spuler, Simone

2017-04-01

To investigate the potential of human satellite cells in muscle regeneration small animal models are useful to evaluate muscle regeneration. To suppress the inherent regeneration ability of the tibialis muscle of mice before transplantation of human muscle fibers, a localized irradiation of the mouse leg should be conducted. We analyzed the feasibility of an image-guided robotic irradiation procedure, a routine treatment method in radiation oncology, for the focal irradiation of mouse legs. After conducting a planning computed tomography (CT) scan of one mouse in its customized mold a three-dimensional dose plan was calculated using a dedicated planning workstation. 18 Gy have been applied to the right anterior tibial muscle of 4 healthy and 12 mice with immune defect in general anesthesia using an image-guided robotic linear accelerator (LINAC). The mice were fixed in a customized acrylic mold with attached fiducial markers for image guided tracking. All 16 mice could be irradiated as prevised without signs of acute radiation toxicity or anesthesiological side effects. The animals survived until scarification after 8, 21 and 49 days as planned. The procedure was straight forward and the irradiation process took 5 minutes to apply the dose of 18 Gy. Localized irradiation of mice legs using a robotic LINAC could be conducted as planned. It is a feasible procedure without recognizable side effects. Image guidance offers precise dose delivery and preserves adjacent body parts and tissues.

Systemic transplantation of human adipose tissue-derived mesenchymal stem cells for the regeneration of irradiation-induced salivary gland damage.

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Jae-Yol Lim

Full Text Available OBJECTIVES: Cell-based therapy has been reported to repair or restore damaged salivary gland (SG tissue after irradiation. This study was aimed at determining whether systemic administration of human adipose-derived mesenchymal stem cells (hAdMSCs can ameliorate radiation-induced SG damage. METHODS: hAdMSCs (1 × 10(6 were administered through a tail vein of C3H mice immediately after local irradiation, and then this infusion was repeated once a week for 3 consecutive weeks. At 12 weeks after irradiation, functional evaluations were conducted by measuring salivary flow rates (SFRs and salivation lag times, and histopathologic and immunofluorescence histochemistry studies were performed to assay microstructural changes, apoptosis, and proliferation indices. The engraftment and in vivo differentiation of infused hAdMSCs were also investigated, and the transdifferentiation of hAdMSCs into amylase-producing SG epithelial cells (SGCs was observed in vitro using a co-culture system. RESULTS: The systemic administration of hAdMSCs exhibited improved SFRs at 12 weeks after irradiation. hAdMSC-transplanted SGs showed fewer damaged and atrophied acinar cells and higher mucin and amylase production levels than untreated irradiated SGs. Immunofluorescence TUNEL assays revealed fewer apoptotic cells in the hAdMSC group than in the untreated group. Infused hAdMSCs were detected in transplanted SGs at 4 weeks after irradiation and some cells were found to have differentiated into SGCs. In vitro, a low number of co-cultured hAdMSCs (13%-18% were observed to transdifferentiate into SGCs. CONCLUSION: The findings of this study indicate that hAdMSCs have the potential to protect against irradiation-induced cell loss and to transdifferentiate into SGCs, and suggest that hAdMSC administration should be viewed as a candidate therapy for the treatment of radiation-induced SG damage.

Prognosis in patients with local recurrence after definitive irradiation for prostatic carcinoma

International Nuclear Information System (INIS)

Kuban, D.A.; el-Mahdi, A.M.; Schellhammer, P.F.

1989-01-01

Of 414 patients with Stage A2-C disease, all with a minimum follow-up period of 3 years, who have been definitively irradiated by external beam therapy or iodine-125 (I-125) implantation for biopsy-proven prostatic adenocarcinoma, 83 patients (20%) have experienced local recurrences. The incidence of distant metastasis was significantly higher in patients with local tumor recurrence (56 of 83; 68%), as compared with those with local control (64 of 331; 19%; P less than 0.001). This difference remained significant within each tumor grade and stage. Subsequently, survival in patients with local recurrence was significantly shorter than in those with local tumor control (66% vs. 89% at 5 years; P = 0.001). Of the 83 patients with local tumor recurrence, 56 had local recurrence and distant metastasis, and 27 had local failure alone, with a median follow-up of 76 months for the latter group. Fifteen of 83 patients with local recurrence (18%) developed major complications secondary to local disease. Three of the 83 (4%) patients were known to die of prostatic recurrence alone and another 11 of 83 (13%) as a result of some combination of local and distant disease. Therefore, in reference to the entire group of definitively irradiated patients, only 0.72% expired solely of complications associated with local tumor recurrence and an additional 2.7% expired of a combination of both local and distant disease

Response of pancreatic cancer to local irradiation with high-energy neutrons

Energy Technology Data Exchange (ETDEWEB)

Cohen, Lionel; Woodruff, Katherine H.; Hendrickson, Frank R.; Kurup, Parvathy D.; Mansell, Joanne; Awschalom, Miguel; Rosenberg, Ivan; Ten Haken, Randall K.

1985-09-15

Seventy-seven patients with locally advanced, nonresectable, biopsy-proven adenocarcinoma of the pancreas were treated by palliative bypass surgery followed by intensive neutron beam irradiation of the primary tumor site. Three dose levels, under 20, 21 to 23, and 24 to 25 Gy, were studied with the use of a treatment plan that included all known disease within a limited target volume, generally under 21. Symptomatic palliation was achieved in the majority of patients. The median survival time was 6 months. One patient remained alive and well without evidence of tumor 5 years after irradiation. Two were free of tumor at autopsy (one had died of intercurrent disease and one of radiation-related complications). A common cause of death was metastatic dissemination. Complication rates were dosedependent; life-threatening complications did not exceed 12% with doses of less than 23 Gy. Autopsies from 19 patients were reviewed. In all, the pancreatic tumor site showed extensive reactive fibrosis. Local control was achieved in two patients, but most had both residual tumor in the pancreas and metastases. Six patients had centrolobular veno-occlusive liver disease. These patients had all received the higher (22–24 Gy) neutron doses. Six patients had hemorrhagic radiation gastroenteritis. Mild skin atrophy and bone marrow hypoplasia were seen in the irradiated volumes. The kidneys and spinal cord showed no radiation effects. The authors conclude that neutron irradiation can provide a good local response with marked regression and fibrosis of the tumor. This response, coupled with many deaths due to metastases, suggests that combined treatment with neutrons and chemotherapy would be worth exploring.

Histological and autoradiographic changes in locally irradiated lymph nodes (an experimental study on rabbits)

International Nuclear Information System (INIS)

Kett, K.; Csere, T.; Lukacs, L.; Szilagyi, K.; Illenyi, L.

1979-01-01

The authors studied the local effect of 3000 Rxl X-ray irradiation on the popliteal lymph nodes of rabbits. Beside the morpho-histological description autoradiography was performed after injection of H 3 -thymidine in the afferent lymphatic of the irradiated knee node. The main finding is the appearence of newly-formed germinal centers between the 6-10 days after irradiation. (orig.) [de

Apoptosis of nasopharyngeal carcinoma cell line (CNE-2) induced by neutron irradiation

International Nuclear Information System (INIS)

Liang Ke; He Shaoqin; Feng Yan; Tang Jinhua; Feng Qinfu; Shen Yu; Yin Weibo; Xu Guozhen; Liu Xinfan; Wang Luhua; Gao Li

1999-01-01

Objective: To study the apoptotic response of the nasopharyngeal carcinoma cell line (CNE-2) induced by neutron irradiation. Methods: CNE-2 cells were cultured as usual. Using the techniques of DNA agarose gel electrophoresis and DNA special fluorescent staining, the status of apoptosis in CNE-2 cells after neutron irradiation was detected. Results: It was shown that the apoptosis can be induced in CNE-2 cell after neutron radiation. Six hrs, after different doses of neutron (0/0.667/1.333/2.000/2.667/3.333 Gy) and X-ray 0/2/4/6/8/10 Gy) irradiation the apoptotic rates were 2.4%, 6.3%, 7.1%, 9.5%, 13.5%, 14.6% and 2.4%, 3.8%, 5.7%, 7.8%, 10.4%, 11.7%, respectively; at 48 hrs they were 18.3%, 21.5%, 22.8%, 29.3%, 34.2% and 13.7%, 17.6%, 21.3%, 25.6%, 28.9%, respectively. At 10 hrs after neutron irradiation the DNA ladder of apoptosis could be detected between 0.667-3.333 Gy doses in CNE-2 cells by DNA agarose gel electrophoresis. Conclusion: Neutron radiation can induce apoptosis in tumor cells. Compared with the X-ray, neutron induces apoptosis in larger extent than X-ray in the same condition; meanwhile, apoptosis after irradiation is dose and time dependent

Renal effects of renal x irradiation and induced autoallergic glomerulonephritis

International Nuclear Information System (INIS)

Rappaport, D.S.

1977-01-01

This study was conducted to determine what, if any, influence a single large x-ray exposure of kidney has on the development and course of an experimental autoallergic glomerulonephritis (EAG) in rats. The EAG was induced by immunization with B. pertussis vaccine and homogenate of homologous kidney tissue and Freund's complete adjuvant. Rats were either immunized, sham-immunized, irradiated (1500 R to right kidney temporarily exteriorized), sham-irradiated, or both immunized and irradiated. Immunized-irradiated animals were irradiated either 4 or 2 weeks prior to, concurrently with, or 1 or 2 weeks after immunization, and were sacrificed at 2, 4, 6, 10, or 14 weeks post-immunization. Immunized-only and sham-immunized-only animals were sacrificed at corresponding post-immunization times, and irradiated-only and sham-irradiated-only animals were sacrificed at corresponding post-irradiation times. Progressive arteriolonephrosclerosis (ANA) was observed in right (irradiated) kidneys following x irradiation. The experimental autoallergic glomerulonephritis (EAG) was observed in both kidneys following immunization. The histopathological changes associated with EAG were distinct from those associated with ANS

A history of study on safety of irradiated foods (3). Induced radioactivity in irradiated foods

International Nuclear Information System (INIS)

Miyahara, Makoto

2006-01-01

Food irradiation can induce a small amount of radioactivity in the foods. The principal mechanisms of the nuclear reactions are (n, γ), (γ, n), (γ, γ'). The resulting nuclear products were found in irradiated foods were Na-24, P-32, Ca-45, C-11, N-13, and O-15 in the food irradiated by 24 MeV electron beam. The total radioactivity is less than 1/1000 of those of K-40 in the case of electron beams below 10 MeV or X rays below 5 MeV. Package materials affected neutron flux in the foods and enhanced the radioactivity. Electron beam machine produces neutrons and increases the flux in food. IAEA recommend to reduce neutron production in the facility. The safety of irradiated food in the radioactivity field still needs more progress. (author)

Radiosensitivity of pulmonary alveolar macrophages in rats exposed to local X-irradiation

International Nuclear Information System (INIS)

Gong Yifen; Fei Lihua; Wu Dechang

1987-01-01

The radiosensitivity of pulmonary alveolar macrophages (PAMs) in rats exposed to local thoracic X-irradiatoin was studied. The percentages of mitotic and labeling cells were used as biological endpoints. The parameters of radiosensitivity of PAMs obtained on the second day after local exposure are as follows: D 0 = 0.68 Gy, Dq = 0.06 Gy, n = 1.1 for mitotic cells and D 0 = 1.04 Gy, Dq = 0.12 Gy, n = 1.12 for labeling cells. The parameters of radiosensitivity of PAMs in bronchical lavage obtained immediately after X-irradiation are: D 0 = 3.56 Gy, Dq = 0.77 Gy, n = 1.24 for labeling cells and D 0 = 3.69 Gy, Dq = 0.35 Gy, n = 1.1 for mitotic cells. The comparison of thses results indicates that the radiation effect on PAMs obtained immediately after X-irradiation is less severe than that of PAMs obtained 2 days later. It might be caused by the delay of cell cycle within 2 days after X-irradiation

Ion irradiation-induced precipitation of Cr23C6 at dislocation loops in austenitic steel

International Nuclear Information System (INIS)

Jin, Shuoxue; Guo, Liping; Luo, Fengfeng; Yao, Zhongwen; Ma, Shuli; Tang, Rui

2013-01-01

The irradiation-induced precipitates in argon ion-irradiated austenitic stainless steel at 550 °C were examined via transmission electron microscopy. The selected-area electron diffraction patterns of precipitates indicated unambiguously that the precipitates were Cr 23 C 6 carbides. It was observed directly for the first time that irradiation-induced Cr 23 C 6 precipitates formed at dislocation loops in austenitic stainless steel, and coarsened with increasing irradiation dose.

Local control and image diagnosis of cases of esophageal carcinoma treated by external and intracavitary irradiation

International Nuclear Information System (INIS)

Hishikawa, Yoshio; Miura, Takashi

1984-01-01

Discussions are made on local control of 31 cases of esophageal carcinoma which were treated by external and intracavitary irradiation between May 1980 and March 1983. X-ray and endoscopic findings have been used for the image diagnosis. Before the begining of radiotherapy, types of esophageal carcinoma were determined from X-ray findings according to Borrmann's classification. There were 10 cases of types 1 and 2, and 21 cases of types 3 and 4. After completion of external and intracvitary irradiation, all 10 cases of types 1 and 2 were locally controlled. Of the 21 cases of types 3 and 4, 8 cases which developed stenosis or deep ulcer after external irradiation all failed in local control. The remaining 13 cases of types 3 and 4 were locally controlled except 2 by radiotherapy. (author)

Gamma ray irradiation to roots of tea-plants and induced mutant system

International Nuclear Information System (INIS)

Takeda, Yoshiyuki; Nekaku, Koji; Wada, Mitsumasa

1990-01-01

In order to utilize the useful mutation which is induced by irradiation for the breeding of tea-plants, the gamma-ray irradiation to the roots of tea-plants was carried out. The samples were the roots of tea-plants of four varieties dug up in February, 1984, and were adjusted to about 20 cm, then, put in the cold storage at 5degC for 9 months till the time of irradiation in November, 1984. However, a part of them was taken out in August, and planted in a field for 76 days to germinate, thereafter, used as the samples. The gamma-ray from a Co-60 source was irradiated in the radiation breeding laboratory of Agriculture Bioresources Research Institute at the total dose of 1, 2 and 3 kR and the dose rate of 500 R/h. The irradiated roots were planted as they are or in the state of being cut, and the rate of germination, the number of buds and the induced mutation were examined. Clear difference was not observed in the rate of germination and the number of buds between the irradiated samples and those without irradiation. The long roots were superior to the short roots regarding these items. The types of the induced mutation were mostly thin leaves, and also yellowing, mottling, fascination and so on occurred. The mutant system lacking trichomes on the back of new leaves is considered to be strong against tea anthracnose, and is valuable. (K.I.)

Gamma ray irradiation to roots of tea-plants and induced mutant system

Energy Technology Data Exchange (ETDEWEB)

Takeda, Yoshiyuki; Nekaku, Koji; Wada, Mitsumasa (National Research Inst. of Vegetables, Ornamental Plants and Tea, Ano, Mie (Japan))

1990-11-01

In order to utilize the useful mutation which is induced by irradiation for the breeding of tea-plants, the gamma-ray irradiation to the roots of tea-plants was carried out. The samples were the roots of tea-plants of four varieties dug up in February, 1984, and were adjusted to about 20 cm, then, put in the cold storage at 5degC for 9 months till the time of irradiation in November, 1984. However, a part of them was taken out in August, and planted in a field for 76 days to germinate, thereafter, used as the samples. The gamma-ray from a Co-60 source was irradiated in the radiation breeding laboratory of Agriculture Bioresources Research Institute at the total dose of 1, 2 and 3 kR and the dose rate of 500 R/h. The irradiated roots were planted as they are or in the state of being cut, and the rate of germination, the number of buds and the induced mutation were examined. Clear difference was not observed in the rate of germination and the number of buds between the irradiated samples and those without irradiation. The long roots were superior to the short roots regarding these items. The types of the induced mutation were mostly thin leaves, and also yellowing, mottling, fascination and so on occurred. The mutant system lacking trichomes on the back of new leaves is considered to be strong against tea anthracnose, and is valuable. (K.I.).

Cell death induced by gamma irradiation of developing skeletal muscle

International Nuclear Information System (INIS)

Olive, M.; Blanco, R.; Rivera, R.; Cinos, C.; Ferrer, I.

1995-01-01

Newborn Sprague-Dawley rats were exposed to a single dose of 2 Gy gamma rays and killed from 6 h to 5 d later. Increased numbers of dying cells, characterised by their extreme chromatin condensation and often nuclear fragmentation were seen in skeletal muscle 6 h after irradiation. Dying cells decreased to nearly normal values 48 h later. In situ labelling of nuclear DNA fragmentation identified individual cells bearing fragmented DNA. The effects of gamma rays were suppressed following cycloheximide i.p. at a dose of 1 μg/g body weight given at the time of irradiation. Taken together, the present morphological and pharmacological results suggest that gamma ray induced cell death in skeletal muscle is apoptotic, and that the process is associated with protein synthesis. Finally, proliferating cell nuclear antigen-immunoreactive cells, which were abundant in control rats, decreased in number 48 h after irradiation. However, a marked increase significantly above normal age values was observed at the 5th day, thus suggesting that regeneration occurs following irradiation-induced cell death in developing muscle. (author)

Influence of Magnolol on the bystander effect induced by alpha-particle irradiation

Energy Technology Data Exchange (ETDEWEB)

Wong, T.P.W.; Law, Y.L. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Tse, A.K.W.; Fong, W.F. [Research and Development Division, School of Chinese Medicine, Hong Kong Baptist University, Baptist University Road, Kowloon Tong (Hong Kong); Yu, K.N. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong)], E-mail: peter.yu@cityu.edu.hk

2010-04-15

In this work, the influence of Magnolol on the bystander effect in alpha-particle irradiated Chinese hamster ovary (CHO) cells was examined. The bystander effect was studied through medium transfer experiments. Cytokinesis-block micronucleus (CBMN) assay was performed to quantify the chromosome damage induced by alpha-particle irradiation. Our results showed that the alpha-particle induced micronuclei (MN) frequencies were suppressed with the presence of Magnolol.

Immunomodulatory effect of captopril and local irradiation on myeloid-derived suppressor cells

International Nuclear Information System (INIS)

Cho, Won Kyung; Shin, Sung Won; Kim, Shin Yeong; Choi, Chang Hoon; Park, Won; Noh, Jae Myoung; Hong, Chang Won

2016-01-01

This study is to investigate the effect of captopril when combined with irradiation. 4T1 (mouse mammary carcinoma) cells were injected in the right hind leg of Balb/c mice. Mice were randomized to four groups; control (group 1), captopril-treated (group 2), irradiated (group 3), irradiated and captopril-treated concurrently (group 4). Captopril was administered by intraperitoneal injection (10 mg/kg) daily and irradiation was delivered on the tumor-bearing leg for 15 Gy in 3 fractions. Surface markers of splenic neutrophils (G-MDSCs) and intratumoral neutrophils (tumor-associated neutrophils [TANs]) were assessed using flow cytometry and expression of vascular endothelial growth factor (VEGF) and hypoxia-inducible factor 1 alpha (HIF-1α) of tumor was evaluated by immunohistochemical (IHC) staining. The mean tumor volumes (±standard error) at the 15th day after randomization were 1,382.0 (±201.2) mm 3 (group 1), 559.9 (±67.8) mm 3 (group 3), and 370.5 (± 48.1) mm 3 (group 4), respectively. For G-MDSCs, irradiation reversed decreased expression of CD 101 from tumor-bearing mice, and additional increase of CD 101 expression was induced by captopril administration. Similar tendency was observed in TANs. The expression of tumor-necrosis factor-associated molecules, CD 120 and CD 137 , are increased by irradiation in both G-MDSCs and TANs. Further increment was observed by captopril except CD 120 in TANs. For IHC staining, VEGF and HIF-1α positivity in tumor cells were decreased when treated with captopril. Captopril is suggested to have additional effect when combined to irradiation in a murine tumor model by modulation of MDSCs and angiogenesis

Time-effect relationship of immunological adaptive response induced by low dose X-irradiation in mice

International Nuclear Information System (INIS)

Zhao Yong; Gong Shouliang; Liu Shuzheng

1995-01-01

Kunming mice irradiated with whole-body X-rays were used to observe time-effect relationship of immunological adaptive response induced by ionizing radiation. The results showed that pre-irradiation dose of 75 mGy X-rays with the intervals of 6-48 h between pre-irradiation and challenge irradiation could induce immunological adaptive response in the spontaneous proliferation of thymocytes and the responses of splenocytes to Con A and LPS in mice at 18-24 h after challenge irradiation with 1.5-2.0 Gy X-rays

A TEM method for analyzing local strain fields in irradiated materials

International Nuclear Information System (INIS)

Bennetch, J.I.; Jesser, W.A.

1983-01-01

Of great interest to the field of fracture mechanics is the strain field in front of a crack tip. In irradiated materials, cavities which naturally form as a result of radiation provide convenient internal markers. If a miniaturized irradiated tensile sample is pulled in situ in a transmission electron microscope (TEM), both the relative displacement of these cavities and their distortion in shape provide information on localized strain on a microscopic level. In addition, the TEM method allows direct correlation of active slip systems with crack propagation characteristics. To illustrate this method a strain field map was constructed about a crack propagating in a helium irradiated type 316 stainless steel sample containing large cavities. (orig.)

Detection of myocardial metabolic abnormalities by 18F-FDG PET/CT and corresponding pathological changes in beagles with local heart irradiation

Energy Technology Data Exchange (ETDEWEB)

Yan, Rul [Nursing College of Shanxi Medical University, Taiyuan (China); Song, Jianbo; Wu, Zhi Fang; Liu, Jian Zhang; Hao, Xin Zhong; Li, Sijin [Dept. of Nuclear Medicine, First Hospital of Shanxi Medical University, Taiyuan (China); Guo, Min [Dept. of Cardiology, First Hospital of Shanxi Medical University, Taiyuan (China); Li, Jianguo [Dept. of Radiological and Environmental Medicine, China Institute for Radiation Protection, Taiyuan (China)

2015-08-15

To determine the efficacy of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in the detection of radiation-induced myocardial damage in beagles by comparing two pre-scan preparation protocols as well as to determine the correlation between abnormal myocardial FDG uptake and pathological findings. The anterior myocardium of 12 beagles received radiotherapy locally with a single X-ray dose of 20 Gy. 18F-FDG cardiac PET/CT was performed at baseline and 3 months after radiation. Twelve beagles underwent two protocols before PET/CT: 12 hours of fasting (12H-F), 12H-F followed by a high-fat diet (F-HFD). Regions of interest were drawn on the irradiation and the non-irradiation fields to obtain their maximal standardized uptake values (SUVmax). Then the ratio of the SUV of the irradiation to the non-irradiation fields (INR) was computed. Histopathological changes were identified by light and electron microscopy. Using the 12H-F protocol, the average INRs were 1.18 ± 0.10 and 1.41 ± 0.18 before and after irradiation, respectively (p = 0.021). Using the F-HFD protocol, the average INRs were 0.99 ± 0.15 and 2.54 ± 0.43, respectively (p < 0.001). High FDG uptake in irradiation field was detected in 33.3% (4/12) of 12H-F protocol and 83.3% (10/12) of F-HFD protocol in visual analysis, respectively (p = 0.031). The pathology of the irradiated myocardium showed obvious perivascular fibrosis and changes in mitochondrial vacuoles. High FDG uptake in an irradiated field may be related with radiation-induced myocardial damage resulting from microvascular damage and mitochondrial injury. An F-HFD preparation protocol used before obtaining PET/CT can improve the sensitivity of the detection of cardiotoxicity associated with radiotherapy.

Recruitment of Gr1(+)CD11b (+)F4/80 (+) population in the bone marrow and spleen by irradiation-induced pulmonary damage.

Science.gov (United States)

Thanasegaran, Suganya; Ito, Sachiko; Nishio, Naomi; Uddin, Mohammad Nizam; Sun, Yang; Isobe, Ken-ichi

2015-04-01

Radiation-induced lung injury is a kind of sterile inflammation, which may lead to morbidity and mortality. The mechanism by which ionizing radiation activate the immune system is not well understood. In the present study, we have investigated the immunological responses induced by local irradiation-induced damage in mouse lung. The left lungs of C57BL/6 mice were irradiated at a high dose of 100 Gy. The histology of the lungs and spleen showed evidences of alveolar inflammation and congestion at 2 weeks after X-ray treatment. Also, prominent increase in cells expressing the cell surface markers, Gr(+)CD11b(+)F4/80(+) and Ly6C(+) Ly6G(+) were observed 2 weeks after X-ray treatment (100 Gy). Gr1(+)CD11b(+)F4/80(+) cell depletion by clodronate treatment reversed the histological effects and also failed to recruit Gr(+)CD11b(+) cells or F4/80(+) cells caused by irradiation. The origin of recruited Gr1(+)CD11b(+) cells was found to be a mixed resident and recruited phenotype.

Vascular damage after acute local irradiation: a light and electron microscope study

International Nuclear Information System (INIS)

Verola, O.; Brocheriou, C.

1986-01-01

A pig model was used to examine histological and ultrastructural changes after high-dose local irradiation. This model was chosen to simulate accidents which have occurred in man, enabling the determination of several post-irradiation phases. After an initial phase, with superficial lesions, ischaemic necrosis occurred 3 weeks after irradiation as the result of early vascular alterations. After 2 months, expanding necrosis became obvious in the deep muscle, preceded by an initial spread of vascular lesions: these alterations were obvious from the 30th day by light microscopy but could be detected by electron microscopy from the 9th day. (author)

SHI induced irradiation effect on Mo/Si interface

International Nuclear Information System (INIS)

Agarwal, Garima; Agarwal, Shivani; Jain, Rajkumar; Lal, Chhagan; Jain, I.P.; Kabiraj, D.; Pandey, Akhilesh

2006-01-01

Present parametric study investigates the characteristics of SHI induced mixed molybdenum silicide film with various ion fluences. The deposition of molybdenum thin films onto the Silicon substrate was performed using e-beam evaporation, while the heavy Au ion irradiation with energy 120 MeV was subsequently applied to form molybdenum silicide. The samples have been characterized by grazing incidence X-ray diffraction (GIXRD) for the identification of phase formation at the interface. Formation of t-Mo 5 Si 3 mixed molybdenum silicide was observed on increasing the ion irradiation fluences. (author)

Irradiation-induced patterning in dilute Cu–Fe alloys

International Nuclear Information System (INIS)

Stumphy, B.; Chee, S.W.; Vo, N.Q.; Averback, R.S.; Bellon, P.; Ghafari, M.

2014-01-01

Compositional patterning in dilute Cu 1−x Fe x (x ≈ 12%) induced by 1.8 MeV Kr + irradiation was studied as a function of temperature using atom probe tomography. Irradiation near room temperature led to homogenization of the sample, whereas irradiation at 300 °C and above led to precipitation and macroscopic coarsening. Between these two temperatures the irradiated alloys formed steady state patterns of composition where precipitates grew to a fixed size. The size in this regime increased somewhat with temperature. It was also observed that the steady state concentrations of Fe in Cu matrix and Cu in the Fe precipitates both greatly exceeded their equilibrium solubilities, with the degree of supersaturation in each phase decreasing with increasing temperature. In the macroscopic coarsening regime, the Fe-rich precipitates showed indications of a “cherry-pit” structure, with Cu precipitates forming within the Fe precipitates. In the patterning regime, interfaces between Fe-rich precipitates and the Cu-rich matrix were irregular and diffuse

Study on apoptosis of prostate cancer cell induced by 125I seed irradiation

International Nuclear Information System (INIS)

Liao Anyan; Wang Junjie; Wang Jidong; Zhuang Hongqing; Zhao Yong

2007-01-01

Objective: To explore the mechanism of apoptosis induced by 125 I seed irradiation on PC3 cells. Methods: Human prostate cancer cell line PC3 was treated by irradiation of 125 I (2.77 cGy/h) with various dose. Agarose gel electrophoresis of DNA and flows cytometry were used to detect the apoptosis of PC3 cells and indirect immunofluorescence assay was used to detect the expression of Bcl-2. The activity of Caspase-3 was measured by Caspase Colorimetric Assay Kits. Results: Apoptosis of PC3 cells could be efficiently induced by 125 I seed irradiation. The apoptotic peaks were found by flow cytometry and DNA ladder appeared on 1.8% agarose gel. The activity of Caspase-3 on PC3 cells treated by 125 I seed irradiation was not changed significantly. Bcl-2 gene expression was down-regulated with the sample concentration increased. Conclusion: 125 I irradiation can induce the apoptosis of PC3 cells and the mechanism of apoptosis is related with down regulation of Bcl-2 gene expression and is not related with Caspase-3 activity. (authors)

Induced variation in potato dry rot fusarium roseum by ultraviolet irradiation

International Nuclear Information System (INIS)

Lee, C.U.

1979-01-01

Variations were readily induced in Fusarium roseum isolated from decayed potato tubers by subjecting its conidia to ultraviolet irradiation. The dosage that resulted in complete absence of developing colonies in five minutes of irradiation did not cause the mortality of conidia for the initial one minute. Eighty eight precent of conidia were killed in three minutes. Approximately 90% of the conidia showed resistance to lethality for the initial two minutes whereas 10% began to show resistance after three minutes of the irradiation. The maximum 42% of color variation was obtained among the surviving conidia. Varients in both decreased and increased pathogenicity were induced in 8% among the color variants. Variations occurred in such other characteristics as growth rate, rigidity of mycelium, and conidia formation. (author)

Electron irradiation induced nanocrystal formation in Cu-borosilicate glass

Energy Technology Data Exchange (ETDEWEB)

Sabri, Mohammed Mohammed; Möbus, Günter, E-mail: g.moebus@sheffield.ac.uk [University of Sheffield, Department of Materials Science and Engineering (United Kingdom)

2016-03-15

Nanoscale writing of Cu nanoparticles in glasses is introduced using focused electron irradiation by transmission electron microscopy. Two types of copper borosilicate glasses, one with high and another with low Cu loading, have been tested at energies of 200–300 keV, and formation of Cu nanoparticles in a variety of shapes and sizes using different irradiation conditions is achieved. Electron energy loss spectroscopy analysis, combined with high-resolution transmission electron microscopy imaging, confirmed the irradiation-induced precipitated nanoparticles as metallic, while furnace annealing of the glass triggered dendrite-shaped particles of copper oxide. Unusual patterns of nanoparticle rings and chains under focused electron beam irradiation are also presented. Conclusively, electron beam patterning of Cu-loaded glasses is a promising alternative route to well-established femtosecond laser photoreduction of Cu ions in glass.

Beam-induced temperature changes in HVEM irradiations

International Nuclear Information System (INIS)

Garner, F.A.; Thomas, L.E.; Gelles, D.S.

1975-01-01

The peak value of the temperature distribution induced by energy loss of 1.0 MeV electrons in traversing a typical HVEM irradiation specimen can be very substantial. The origin and various features of this distribution were analyzed for a variety of specimen geometries. The major parametric dependencies are shown to be relatively independent of specimen geometry, however, and allow the definition of a scaling relationship that can be employed to predict temperature rises in materials that cannot be measured directly. The use of this scaling relationship requires that the experimenter minimize perturbations of the heat flow due to proximity of the central hole in the specimen. An experimental method of determining directly the magnitude and distribution of beam-induced temperature profiles was developed which utilizes the order-disorder transformation in Fe 3 Al and Cu 3 Au. Scaling of experimentally determined temperature changes leads to more realistic estimates of the total temperature rise than are currently available in various literature tabulations. The factors which determine the optimum selection of irradiation parameters for a given experiment are also discussed

Fatigue behavior of Type 316 stainless steel following neutron irradiation inducing helium

International Nuclear Information System (INIS)

Grossbeck, M.L.; Liu, K.C.

1980-01-01

Since a tokamak reactor operates in a cyclic mode, thermal stresses will result in fatigue in structural components, especially in the first wall and blanket. There has been limited work on fatigue in irradiated alloys but none on irradiated materials containing significant amounts of irradiation-induced helium. To provide scoping data and to study the effects of irradiation on fatigue behavior, 20%-cold-worked type 316 stainless steel from the MFE reference heat was studied

Gastroprotective effect of kefir on ulcer induced in irradiated rats.

Science.gov (United States)

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. Copyright © 2015 Elsevier B.V. All rights reserved.

Evaluation of Chemical Changes in Some Soybean Mutants Induced by Gamma Irradiation

International Nuclear Information System (INIS)

Abd-Elkalik, K.; Mekkawy, S.H.; El-Demerdash, H.M.

2010-01-01

The Egyptian soybean cultivar Giza-22 was used to induce genetic variability by using gamma rays at dose levels of 100, 150 and 200 Gy. Sixteen mutants (including parental cultivar) were evaluated in M3 generation for their agronomic traits and chemical analysis was done in seeds of M3 generation. Four mutants A21 (150 Gy), A22, A23 and A24 (200 Gy) showed superiority in their agronomic traits compared with parental cultivar. The results of chemical analysis of seeds of M3 generation showed that, oil and energy contents were unaffected by irradiation treatments while protein contents were significantly increased at doses 150 and 200 Gy. Phenolic and tannin contents in seeds of M3 generation showed no significant changes in their percentages due to irradiation treatments. Gamma irradiation significantly increased in linoleic acid content in most of the mutants compared with the control (Giza-22), whereas, there were decreases in linolenic acid content. Investigation of amino acid composition of mutants of M3 generation revealed significant increases in the essential amino acids in most mutants induced by gamma irradiation at 150 and 200 Gy. It could be suggested that the use of gamma irradiation can induce an improvement of the oil and protein composition in soybean

Immunomodulatory effect of captopril and local irradiation on myeloid-derived suppressor cells

Energy Technology Data Exchange (ETDEWEB)

Cho, Won Kyung; Shin, Sung Won; Kim, Shin Yeong; Choi, Chang Hoon; Park, Won; Noh, Jae Myoung [Dept. of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Hong, Chang Won [Dept. of Physiology, Kyungpook National University School of Medicine, Daegu (Korea, Republic of)

2016-09-15

This study is to investigate the effect of captopril when combined with irradiation. 4T1 (mouse mammary carcinoma) cells were injected in the right hind leg of Balb/c mice. Mice were randomized to four groups; control (group 1), captopril-treated (group 2), irradiated (group 3), irradiated and captopril-treated concurrently (group 4). Captopril was administered by intraperitoneal injection (10 mg/kg) daily and irradiation was delivered on the tumor-bearing leg for 15 Gy in 3 fractions. Surface markers of splenic neutrophils (G-MDSCs) and intratumoral neutrophils (tumor-associated neutrophils [TANs]) were assessed using flow cytometry and expression of vascular endothelial growth factor (VEGF) and hypoxia-inducible factor 1 alpha (HIF-1α) of tumor was evaluated by immunohistochemical (IHC) staining. The mean tumor volumes (±standard error) at the 15th day after randomization were 1,382.0 (±201.2) mm{sup 3} (group 1), 559.9 (±67.8) mm{sup 3} (group 3), and 370.5 (± 48.1) mm{sup 3} (group 4), respectively. For G-MDSCs, irradiation reversed decreased expression of CD{sub 101} from tumor-bearing mice, and additional increase of CD{sub 101} expression was induced by captopril administration. Similar tendency was observed in TANs. The expression of tumor-necrosis factor-associated molecules, CD{sub 120} and CD{sub 137}, are increased by irradiation in both G-MDSCs and TANs. Further increment was observed by captopril except CD{sub 120} in TANs. For IHC staining, VEGF and HIF-1α positivity in tumor cells were decreased when treated with captopril. Captopril is suggested to have additional effect when combined to irradiation in a murine tumor model by modulation of MDSCs and angiogenesis.

Caffeine-induced hematological changes after whole-body irradiation in rat

Energy Technology Data Exchange (ETDEWEB)

Kim, Jin Kyu [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Kim, Ji Hyang; Yoon Yong Dal [Hanyang University, Seoul (Korea, Republic of)

2004-07-01

Recent research indicated dietary antioxidants were useful radioprotectors to protect organisms against radiation-induced tissue lethality and other deleterious effects. Radioprotective effects of vitamin C have been demonstrated in certain cells and animals, which would result from scavenging free radicals. Moreover, the previous studies indicated that caffeine had been shown to potently act the radioprotector in irradiated mice. However it is not clear exactly about effects of caffeine treatments chronically after irradiation. So the present studies were designed to identify the hematological effect of caffeine treatments chronically one month after whole-body gamma irradiation.

Identification of irradiation treatment in processed food. Pt. 2. Evaluation of a SPE-method for analyzing irradiation induced hydrocarbons

International Nuclear Information System (INIS)

Hartmann, M.; Ammon, J.; Berg, H.

1996-01-01

This paper deals with a solid phase extraction (SPE) method for the isolation of irradiation induced hydrocarbons which can replace the column chromatography described in the paragraph 35 LMBG (German Food Law) procedure L06.00-37. Using this new method, only a tenth of solvents and column material is necessary. The SPE method was a good as LC-LC-GC/FID or LC-LC-GC/MS in analyzing new or complex matrices like paprika or salmon. Additionally, it is fast, cheap and easy to perform. As far as we know, the detection of irradiation traetment in paprika powder by analyzing irradiation induced hydrocarbons has not been described before. The new method is a good alternative for the commonly used thermoluminescence procedure. (orig.) [de

Bilateral streptococcal corneoscleritis complicating β irradiation induced scleral necrosis

International Nuclear Information System (INIS)

Moriarty, A.P.; Crawford, G.J.; McAllister, I.L.; Constable, I.J.

1993-01-01

Bacterial corneoscleritis may complicate scleral necrosis induced by β irradiation following pterygium removal. Previous cases have been unilateral. The authors report a case of severe bilateral corneoscleritis caused by Streptococcus pneumoniae. (author)

Characterisation of irradiation-induced defects in ZnO single crystals

International Nuclear Information System (INIS)

Prochazka, I; Cizek, J; Lukac, F; Melikhova, O; Valenta, J; Havranek, V; Anwand, W; Skuratov, V A; Strukova, T S

2016-01-01

Positron annihilation spectroscopy (PAS) combined with optical methods was employed for characterisation of defects in the hydrothermally grown ZnO single crystals irradiated by 167 MeV Xe 26+ ions to fluences ranged from 3×10 12 to 1×10 14 cm -2 . The positron lifetime (LT), Doppler broadening as well as slow-positron implantation spectroscopy (SPIS) techniques were involved. The ab-initio theoretical calculations were utilised for interpretation of LT results. The optical transmission and photoluminescence measurements were conducted, too. The virgin ZnO crystal exhibited a single component LT spectrum with a lifetime of 182 ps which is attributed to saturated positron trapping in Zn vacancies associated with hydrogen atoms unintentionally introduced into the crystal during the crystal growth. The Xe ion irradiated ZnO crystals have shown an additional component with a longer lifetime of ≈ 360 ps which comes from irradiation-induced larger defects equivalent in size to clusters of ≈10 to 12 vacancies. The concentrations of these clusters were estimated on the basis of combined LT and SPIS data. The PAS data were correlated with irradiation induced changes seen in the optical spectroscopy experiments. (paper)

Characterisation of irradiation-induced defects in ZnO single crystals

Science.gov (United States)

Prochazka, I.; Cizek, J.; Lukac, F.; Melikhova, O.; Valenta, J.; Havranek, V.; Anwand, W.; Skuratov, V. A.; Strukova, T. S.

2016-01-01

Positron annihilation spectroscopy (PAS) combined with optical methods was employed for characterisation of defects in the hydrothermally grown ZnO single crystals irradiated by 167 MeV Xe26+ ions to fluences ranged from 3×1012 to 1×1014 cm-2. The positron lifetime (LT), Doppler broadening as well as slow-positron implantation spectroscopy (SPIS) techniques were involved. The ab-initio theoretical calculations were utilised for interpretation of LT results. The optical transmission and photoluminescence measurements were conducted, too. The virgin ZnO crystal exhibited a single component LT spectrum with a lifetime of 182 ps which is attributed to saturated positron trapping in Zn vacancies associated with hydrogen atoms unintentionally introduced into the crystal during the crystal growth. The Xe ion irradiated ZnO crystals have shown an additional component with a longer lifetime of ≈ 360 ps which comes from irradiation-induced larger defects equivalent in size to clusters of ≈10 to 12 vacancies. The concentrations of these clusters were estimated on the basis of combined LT and SPIS data. The PAS data were correlated with irradiation induced changes seen in the optical spectroscopy experiments.

Effect of microstructure on radiation induced segregation and depletion in ion irradiated SS316 steel

International Nuclear Information System (INIS)

Jin, Hyung Ha; Kwon, Sang Chul; Kwon, Jun Hyun

2011-01-01

Irradiation assisted stress corrosion cracking (IASCC), void swelling and irradiation induced hardening are caused by change of characteristics of material by neutron irradiation, stress state of material and environmental situation. It has been known that chemical compositions varies at grain boundary (GB) significantly with fluence level and the depletion of Cr element at GB has been considered as one of important factors causing material degradation, especially, IASCC in austenitic stainless steel. However, experimental results of IASCC under PWR condition were directly not connected with Cr depletion phenomenon by neutron irradiation. Because the mechanism of IASCC under PWR has not yet been clearly understood in spite of many energetic researches, fundamental researches about radiation induced segregation and depletion in irradiated austenitic stainless steels have been attracted again. In this work, an effect of residual microstructure on radiation induced segregation and depletion of alloy elements at GB was investigated in ion irradiated SS316 steel using transmission electron microscope (TEM) with energy dispersive spectrometer (EDS)

Study on DNA Damage Induced by Neon Beam Irradiation in Saccharomyces Cerevisiae

International Nuclear Information System (INIS)

Lu Dong; Li Wenjian; Wu Xin; Wang Jufang; Ma Shuang; Liu Qingfang; He Jinyu; Jing Xigang; Ding Nan; Dai Zhongying; Zhou Jianping

2010-01-01

Yeast strain Saccharomyces cerevisiae was irradiated with different doses of 85 MeV/u 20 Ne 10+ to investigate DNA damage induced by heavy ion beam in eukaryotic microorganism. The survival rate, DNA double strand breaks (DSBs) and DNA polymorphic were tested after irradiation. The results showed that there were substantial differences in DNA between the control and irradiated samples. At the dose of 40 Gy, the yeast cell survival rate approached 50%, DNA double-strand breaks were barely detectable, and significant DNA polymorphism was observed. The alcohol dehydrogenase II gene was amplified and sequenced. It was observed that base changes in the mutant were mainly transversions of T→G and T→C. It can be concluded that heavy ion beam irradiation can lead to change in single gene and may be an effective way to induce mutation.

Study on DNA Damage Induced by Neon Beam Irradiation in Saccharomyces Cerevisiae

Science.gov (United States)

Lu, Dong; Li, Wenjian; Wu, Xin; Wang, Jufang; Ma, Shuang; Liu, Qingfang; He, Jinyu; Jing, Xigang; Ding, Nan; Dai, Zhongying; Zhou, Jianping

2010-12-01

Yeast strain Saccharomyces cerevisiae was irradiated with different doses of 85 MeV/u 20Ne10+ to investigate DNA damage induced by heavy ion beam in eukaryotic microorganism. The survival rate, DNA double strand breaks (DSBs) and DNA polymorphic were tested after irradiation. The results showed that there were substantial differences in DNA between the control and irradiated samples. At the dose of 40 Gy, the yeast cell survival rate approached 50%, DNA double-strand breaks were barely detectable, and significant DNA polymorphism was observed. The alcohol dehydrogenase II gene was amplified and sequenced. It was observed that base changes in the mutant were mainly transversions of T→G and T→C. It can be concluded that heavy ion beam irradiation can lead to change in single gene and may be an effective way to induce mutation.

Branch formation induced by microbeam irradiation of Adiantum protonemata

International Nuclear Information System (INIS)

Wada, M.

1998-01-01

Branches were induced in centrifuged Adiantum protonemal cells by partial irradiation with polarized red light. Nuclear behavior and microtubule pattern change during branch formation were investigated. A branch formed at any part where a red microbeam was focused along a long apical cell. The nucleus moved towards the irradiated area and remained there until a branch developed. The pattern of microtubules changed from parallel to oblique at the irradiated area and then a transverse arrangement of microtubules appeared on both sides of the area. It appeared as if the nucleus was suspended between two microtubule rings. This nuclear behavior and the changes in microtubule pattern were different from those observed during branch formation under whole cell irradiation. From the results of this work we suggest that there is an importance for precise control of experimental conditions

Elevated sodium chloride concentrations enhance the bystander effects induced by low dose alpha-particle irradiation

Energy Technology Data Exchange (ETDEWEB)

Han Wei; Zhu Lingyan; Jiang Erkang; Wang Jun; Chen Shaopeng; Bao Linzhi; Zhao Ye; Xu An; Yu Zengliang [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Wu Lijun [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)], E-mail: ljw@ipp.ac.cn

2007-11-01

Previous studies have shown that high NaCl can be genotoxic, either alone or combined with irradiation. However, little is known about the relationship between environmental NaCl at elevated conditions and radiation-induced bystander effects (RIBE). RIBE, which has been considered as non-targeted bystander responses, has been demonstrated to occur widely in various cell lines. In the present study, RIBE under the elevated NaCl culture condition was assessed in AG 1522 cells by both the induction of {gamma}-H2AX, a reliable marker of DNA double-strand break (DSB) for the early process (<1 h post irradiation), and the generation of micronuclei (MN), a sensitive marker for relative long process of RIBE. Our results showed that in the absence of irradiation, NaCl at elevated concentration such as 8.0, 9.0 and 10.0 g/L did not significantly increase the frequency of {gamma}-H2AX foci-positive cells and the number of foci per positive cell comparing with that NaCl at a normal concentration (6.8 g/L). However, with 0.2 cGy {alpha}-particle irradiation, the induced fraction of {gamma}-H2AX foci-positive cells and the number of induced {gamma}-H2AX foci per positive cell were significantly increased in both irradiated and adjacent non-irradiated regions. Similarly, the induction of MN by 0.2 cGy {alpha}-particle irradiation also increased with the elevated NaCl concentrations. With N{sup G}-methyl-L-arginine, an inhibitor of nitric oxide synthase, the induced fraction of foci-positive cells was effectively inhibited both in 0.2 cGy {alpha}-particle irradiated and adjacent non-irradiated regions under either normal or elevated NaCl conditions. These results suggested that the cultures with elevated NaCl medium magnified the damage effects induced by the low dose {alpha}-particle irradiation and nitric oxide generated by irradiation was also very important in this process.

Evaluation of Some Chemical Characteristics of barley Mutants induced by Gamma Irradiation

International Nuclear Information System (INIS)

Abdeldaiem, M.H.; Ali, H.G.M.

2011-01-01

This study aims to evaluate the antioxidant activity of acetonic extract from some barley mutations (P1, P2 and P3 varieties) induced by gamma irradiation as compared with local barley variety (Hordeum vulgare L.) as control. Barley samples were obtained from Plant Breeding Unit, Plant Research Department, Nuclear Research Centre, Atomic Energy Authority, Egypt. The measurements of the antioxidant activity using a radical scavenging capacity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ?-carotene bleaching assay were assessed in the barley acetonic extract. Furthermore, amino acids composition of barley mutant samples was determined. The results indicated that the acetonic extract of barley varieties under investigation possess marked antioxidant and anti radical capacities. The data showed that the acetonic extract of barley mutant P1 possessed the higher antioxidant activity as compared with the antioxidant activities of acetonic extract from control and other barley mutant samples. Meanwhile, the flour of barley mutations under investigation contained trace elements of iron, copper and manganese. GC and mass analyses were used to identify the active compound of extract of control and mutant barley samples. The results illustrated that the main components of the control sample of barely extract was pentane, 3 methyl (47.73%) while gamma irradiation caused noticeable change in the relative percentage of some components of acetonic extract from barley mutant samples. Moreover, the results presented that changes were disappeared, and some compounds of the acetonic extract from mutant barley samples were appeared. Furthermore, the results exhibited that barley flour supplemented with wheat flour at 30% level produced acceptable cookies. Accordingly, the phenolic constituents of barley acetonic extract induced by gamma irradiation, especially samples of P1 mutant, may have a future role as ingredients in the development of functional foods.

Alpha-particle irradiation induced defects in SiO2 films of Si-SiO2 structures

International Nuclear Information System (INIS)

Koman, B.P.; Gal'chynskyy, O.V.; Kovalyuk, R.O.; Shkol'nyy, A.K.

1996-01-01

The aim of the work was to investigate alpha-particle irradiation induced defects in Si-SiO 2 structures by means of the thermostimulated discharge currents (TSDC) analysis. The object of investigation were (p-Si)-SiO 2 structures formed by a combined oxidation of the industrial p-Si wafers in dry and wet oxygen at temperature of 1150 C. The TSD currents were investigated in the temperature range between 90 and 500 K under linear heating rate. Pu 238 isotopes were the source of alpha-particles with an energy of 4-5 MeV and a density of 5.10 7 s -1 cm -2 . The TSD current curves show two peculiar maxima at about 370 and 480 K. Alpha-particle irradiation doesn't affect the general shape of the TSDC curves but leads to a shift of the maximum at 370 K and reduces the total electret charge which is accumulated in the Si-SiO 2 structures during polarization. The energy distribution function of the defects which are involved in SiO 2 polarization has been calculated. It showes that defects with activation energies of about 0.8 and 1.0 eV take part in forming the electret state, and these activation energies have certain energy distributions. It has been found that the TSDC maximum at 370 K has space charge nature and is caused by migration of hydrogen ions. In irradiated samples hydrogen and natrium ions localize on deeper trapping centres induced by alpha-particle irradiation. (orig.)

Inhomogeneous strain induced by fast neutron irradiation in NaKSO4 crystals

International Nuclear Information System (INIS)

Kandil, S.H.; Kassem, M.E.; El-Khatib, A.; El-Gamal, M.A.; El-Wahidy, E.F.

1987-01-01

The paper reports the effect of fast neutron irradiation on the thermal properties of NaKSO 4 crystals in the temperature range 400-475 K. Results are presented for the thermal expansion, tensile strain and specific heat of NaKSO 4 , as a function of neutron irradiation dose. All these results revealed an inhomogeneous strain induced by the radiation. It is suggested that this induced inhomogeneous strain could be used to detect neutron exposure doses. (UK)

Attempts of local irradiation of cells by microbeam. From ultraviolet to heavy particles

Energy Technology Data Exchange (ETDEWEB)

Kobayashi, Yasuhiko [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

2002-03-01

This review describes the history of attempts of local irradiation of cells by microbeam and present status of the study. Local irradiation of cells was attempted as early as in 1912 with use of short {alpha}-particle range and of focused UV beams. After the war, laser microbeams were then developed for microsurgery in embryology. In addition, microbeams of electron generated from the gun and of X-ray collimated were developed. In 1950s, the electron microbeam was generated from Van de Graaff accelerator in Chicago University and proton, deuteron and He-ion microbeams from the cyclotron, in BNL. In 1980s, Gesellschaft fuer Schwerionenforshung (Germany) used heavy ion microbeams from C to U generated from the linear accelerator and PNL, proton to {sup 4}He-ion microbeams from the tandem-electrostatic accelerator. At present in 2002, the equipments for microbeam for cell irradiation are the Van de Graaff accelerators in Gray Cancer Institute (England) and in Columbia University, and the cyclotron in TIARA in Japan. The purpose of the study in TIARA is to develop a system to generate heavy particle microbeams for cell irradiation for analysis of the biological effect of ultra-low fluence, high LET heavy particles like the galactic cosmic ray. Recently, the CHO-KI cell nucleus is irradiated by {sup 40}Ar and {sup 20}Ne ions. (K.H.)

Attempts of local irradiation of cells by microbeam. From ultraviolet to heavy particles

International Nuclear Information System (INIS)

Kobayashi, Yasuhiko

2002-01-01

This review describes the history of attempts of local irradiation of cells by microbeam and present status of the study. Local irradiation of cells was attempted as early as in 1912 with use of short α-particle range and of focused UV beams. After the war, laser microbeams were then developed for microsurgery in embryology. In addition, microbeams of electron generated from the gun and of X-ray collimated were developed. In 1950s, the electron microbeam was generated from Van de Graaff accelerator in Chicago University and proton, deuteron and He-ion microbeams from the cyclotron, in BNL. In 1980s, Gesellschaft fuer Schwerionenforshung (Germany) used heavy ion microbeams from C to U generated from the linear accelerator and PNL, proton to 4 He-ion microbeams from the tandem-electrostatic accelerator. At present in 2002, the equipments for microbeam for cell irradiation are the Van de Graaff accelerators in Gray Cancer Institute (England) and in Columbia University, and the cyclotron in TIARA in Japan. The purpose of the study in TIARA is to develop a system to generate heavy particle microbeams for cell irradiation for analysis of the biological effect of ultra-low fluence, high LET heavy particles like the galactic cosmic ray. Recently, the CHO-KI cell nucleus is irradiated by 40 Ar and 20 Ne ions. (K.H.)

Beta-irradiation used for systemic radioimmunotherapy induces apoptosis and activates apoptosis pathways in leukaemia cells

International Nuclear Information System (INIS)

Friesen, Claudia; Lubatschofski, Annelie; Debatin, Klaus-Michael; Kotzerke, Joerg; Buchmann, Inga; Reske, Sven N.

2003-01-01

Beta-irradiation used for systemic radioimmunotherapy (RIT) is a promising treatment approach for high-risk leukaemia and lymphoma. In bone marrow-selective radioimmunotherapy, beta-irradiation is applied using iodine-131, yttrium-90 or rhenium-188 labelled radioimmunoconjugates. However, the mechanisms by which beta-irradiation induces cell death are not understood at the molecular level. Here, we report that beta-irradiation induced apoptosis and activated apoptosis pathways in leukaemia cells depending on doses, time points and dose rates. After beta-irradiation, upregulation of CD95 ligand and CD95 receptor was detected and activation of caspases resulting in apoptosis was found. These effects were completely blocked by the broad-range caspase inhibitor zVAD-fmk. In addition, irradiation-mediated mitochondrial damage resulted in perturbation of mitochondrial membrane potential, caspase-9 activation and cytochrome c release. Bax, a death-promoting protein, was upregulated and Bcl-x L , a death-inhibiting protein, was downregulated. We also found higher apoptosis rates and earlier activation of apoptosis pathways after gamma-irradiation in comparison to beta-irradiation at the same dose rate. Furthermore, irradiation-resistant cells were cross-resistant to CD95 and CD95-resistant cells were cross-resistant to irradiation, indicating that CD95 and irradiation used, at least in part, identical effector pathways. These findings demonstrate that beta-irradiation induces apoptosis and activates apoptosis pathways in leukaemia cells using both mitochondrial and death receptor pathways. Understanding the timing, sequence and molecular pathways of beta-irradiation-mediated apoptosis may allow rational adjustment of chemo- and radiotherapeutic strategies. (orig.)

Minocycline ameliorates cognitive impairment induced by whole-brain irradiation: an animal study

International Nuclear Information System (INIS)

Zhang, Liyuan; Li, Kun; Sun, Rui; Zhang, Yuan; Ji, JianFeng; Huang, Peigeng; Yang, Hongying; Tian, Ye

2014-01-01

It has been long recognized that cranial irradiation used for the treatment of primary and metastatic brain tumor often causes neurological side-effects such as intellectual impairment, memory loss and dementia, especially in children patients. Our previous study has demonstrated that whole-brain irradiation (WBI) can cause cognitive decline in rats. Minocycline is an antibiotic that has shown neuroprotective properties in a variety of experimental models of neurological diseases. However, whether minocycline can ameliorate cognitive impairment induced by ionizing radiation (IR) has not been tested. Thus this study aimed to demonstrate the potential implication of minocycline in the treatment of WBI-induced cognitive deficits by using a rat model. Sprague Dawley rats were cranial irradiated with electron beams delivered by a linear accelerator with a single dose of 20 Gy. Minocycline was administered via oral gavages directly into the stomach before and after irradiation. The open field test was used to assess the anxiety level of rats. The Morris water maze (MWM) was used to assess the spatial learning and memory of rats. The level of apoptosis in hippocampal neurons was measured using immunohistochemistry for caspase-3 and relative markers for mature neurons (NeuN) or for newborn neurons (Doublecortin (DCX)). Neurogenesis was determined by BrdU incorporation method. Neither WBI nor minocycline affected the locomotor activity and anxiety level of rats. However, compared with the sham-irradiated controls, WBI caused a significant loss of learning and memory manifest as longer latency to reach the hidden platform in the MWM task. Minocycline intervention significantly improved the memory retention of irradiated rats. Although minocycline did not rescue neurogenesis deficit caused by WBI 2 months post-IR, it did significantly decreased WBI-induced apoptosis in the DCX positive neurons, thereby resulting in less newborn neuron depletion 12 h after irradiation

Protective effects of nelumbo nucifera against {gamma}-irradiation-induced lipid peroxidation in mice urine

Energy Technology Data Exchange (ETDEWEB)

Jeong, Il Yun; Park, Yong Dae; Jin, Caang Hyun; Choi, Dae Seong [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of); Lee, Hyo Jung [Gwangju Institute of Science and Technology, Gwangju (Korea, Republic of)

2009-12-15

The radioprotective effect of isoquercitrin-abundant fraction (IAF) of N. nucifera Gaertn. Ieaf extract against {gamma}-irradiation-induced oxidative stress was evaluated by the lipid peroxidation-derived aldehydes (LPDAs) as a marker for oxidative risk in mice urine, and the DNA damage using comet assay in RAW 264.7 cells. Mice that were treated with IAF (50 mg/kg) and {gamma}-irradiation showed considerably decreased LPDA levels relative to those that had received {gamma}-irradiation alone. Furthermore, pretreatment with IAF resulted in a significant decrease in the amount of DNA damage in cells. It is demonstrated that pretreatment with IAF of N. nucifera Gaertn. gives protection against irradiation-induced cellular damage.

External gamma irradiation-induced effects in early-life stages of zebrafish, Danio rerio

International Nuclear Information System (INIS)

Gagnaire, B.; Cavalié, I.; Pereira, S.; Floriani, M.; Dubourg, N.; Camilleri, V.; Adam-Guillermin, C.

2015-01-01

Highlights: • The present study aimed to evaluate the effects of gamma rays on zebrafish larvae. • Different techniques were used: gene expression, biochemistry, microscopy and macroscopical observations. • The results showed that gamma irradiation can alter embryo-larval development at several levels of organization. - Abstract: In the general context of validation of tools useful for the characterization of ecological risk linked to ionizing radiation, the effects of an external gamma irradiation were studied in zebrafish larvae irradiated for 96 h with two dose rates: 0.8 mGy/d, which is close to the level recommended to protect ecosystems from adverse effects of ionizing radiation (0.24 mGy/d) and a higher dose rate of 570 mGy/d. Several endpoints were investigated, such as mortality, hatching, and some parameters of embryo-larval development, immunotoxicity, apoptosis, genotoxicity, neurotoxicity and histological alterations. Results showed that an exposure to gamma rays induced an acceleration of hatching for both doses and a decrease of yolk bag diameter for the highest dose, which could indicate an increase of global metabolism. AChE activity decreased with the low dose rate of gamma irradiation and alterations were also shown in muscles of irradiated larvae. These results suggest that gamma irradiation can induce damages on larval neurotransmission, which could have repercussions on locomotion. DNA damages, basal ROS production and apoptosis were also induced by irradiation, while ROS stimulation index and EROD biotransformation activity were decreased and gene expression of acetylcholinesterase, choline acetyltransferase, cytochrome p450 and myeloperoxidase increased. These results showed that ionizing radiation induced an oxidative stress conducting to DNA damages. This study characterized further the modes of action of ionizing radiation in fish.

External gamma irradiation-induced effects in early-life stages of zebrafish, Danio rerio

Energy Technology Data Exchange (ETDEWEB)

Gagnaire, B., E-mail: beatrice.gagnaire@irsn.fr [Institut de Radioprotection et de Sureté Nucléaire (IRSN), PRP-ENV/SERIS/LECO, Cadarache, Saint-Paul-lez-Durance 13115 (France); Cavalié, I. [Institut de Radioprotection et de Sureté Nucléaire (IRSN), PRP-ENV/SERIS/LECO, Cadarache, Saint-Paul-lez-Durance 13115 (France); Pereira, S. [Neolys Diagnostics, Lyon 69373 (France); Floriani, M.; Dubourg, N.; Camilleri, V.; Adam-Guillermin, C. [Institut de Radioprotection et de Sureté Nucléaire (IRSN), PRP-ENV/SERIS/LECO, Cadarache, Saint-Paul-lez-Durance 13115 (France)

2015-12-15

Highlights: • The present study aimed to evaluate the effects of gamma rays on zebrafish larvae. • Different techniques were used: gene expression, biochemistry, microscopy and macroscopical observations. • The results showed that gamma irradiation can alter embryo-larval development at several levels of organization. - Abstract: In the general context of validation of tools useful for the characterization of ecological risk linked to ionizing radiation, the effects of an external gamma irradiation were studied in zebrafish larvae irradiated for 96 h with two dose rates: 0.8 mGy/d, which is close to the level recommended to protect ecosystems from adverse effects of ionizing radiation (0.24 mGy/d) and a higher dose rate of 570 mGy/d. Several endpoints were investigated, such as mortality, hatching, and some parameters of embryo-larval development, immunotoxicity, apoptosis, genotoxicity, neurotoxicity and histological alterations. Results showed that an exposure to gamma rays induced an acceleration of hatching for both doses and a decrease of yolk bag diameter for the highest dose, which could indicate an increase of global metabolism. AChE activity decreased with the low dose rate of gamma irradiation and alterations were also shown in muscles of irradiated larvae. These results suggest that gamma irradiation can induce damages on larval neurotransmission, which could have repercussions on locomotion. DNA damages, basal ROS production and apoptosis were also induced by irradiation, while ROS stimulation index and EROD biotransformation activity were decreased and gene expression of acetylcholinesterase, choline acetyltransferase, cytochrome p450 and myeloperoxidase increased. These results showed that ionizing radiation induced an oxidative stress conducting to DNA damages. This study characterized further the modes of action of ionizing radiation in fish.

EPR spectra induced by gamma-irradiation of some dry medical herbs

Science.gov (United States)

Yordanov, N. D.; Lagunov, O.; Dimov, K.

2009-04-01

The radiation-induced EPR spectra in some medical herbs are reported. The samples studied are: (i) leaves of nettle, common balm, peppermint and thyme; (ii) stalks of common balm, thyme, milfoil, yarrow and marigold; (iii) blossoms of yarrow and marigold; (iv) blossoms and leaves of hawthorn and tutsan; and (v) roots of common valerian, nettle, elecampane (black and white), restharrows and carlina. Before irradiation all samples exhibit one weak anisotropic singlet EPR line with effective g-value of 2.0050±0.0002. The radiation-induced spectra fall into three groups. EPR spectra of irradiated blossoms of yarrow and marigold, stalks of common balm, thyme, tutsan and yarrow as well as roots of common valerian, nettle and elecampane (black and white) show "cellulose-like" EPR spectrum typical for irradiated plants. It is characterized by one intense central line with g=2.0050±0.0005 and two weak satellite lines situated ca. 30 G left and right to it. EPR spectra of gamma-irradiated restharrows and carlina are complex. They may be represented by one triplet corresponding to the "cellulose-like" EPR spectrum, one relatively intense singlet, situated in the center of the spectrum, and five weak additional satellite lines left and right to the center. The last spectrum was assigned as "carbohydrate-like" type. Only one intense EPR singlet with g=2.0048±0.0005 was recorded after irradiation of leaves of nettle and common balm. The lifetime of the radiation-induced EPR spectra was followed for a period of 3 months.

EPR spectra induced by gamma-irradiation of some dry medical herbs

International Nuclear Information System (INIS)

Yordanov, N.D.; Lagunov, O.; Dimov, K.

2009-01-01

The radiation-induced EPR spectra in some medical herbs are reported. The samples studied are: (i) leaves of nettle, common balm, peppermint and thyme; (ii) stalks of common balm, thyme, milfoil, yarrow and marigold; (iii) blossoms of yarrow and marigold; (iv) blossoms and leaves of hawthorn and tutsan; and (v) roots of common valerian, nettle, elecampane (black and white), restharrows and carlina. Before irradiation all samples exhibit one weak anisotropic singlet EPR line with effective g-value of 2.0050±0.0002. The radiation-induced spectra fall into three groups. EPR spectra of irradiated blossoms of yarrow and marigold, stalks of common balm, thyme, tutsan and yarrow as well as roots of common valerian, nettle and elecampane (black and white) show 'cellulose-like' EPR spectrum typical for irradiated plants. It is characterized by one intense central line with g=2.0050±0.0005 and two weak satellite lines situated ca. 30 G left and right to it. EPR spectra of gamma-irradiated restharrows and carlina are complex. They may be represented by one triplet corresponding to the 'cellulose-like' EPR spectrum, one relatively intense singlet, situated in the center of the spectrum, and five weak additional satellite lines left and right to the center. The last spectrum was assigned as 'carbohydrate-like' type. Only one intense EPR singlet with g=2.0048±0.0005 was recorded after irradiation of leaves of nettle and common balm. The lifetime of the radiation-induced EPR spectra was followed for a period of 3 months

EPR spectra induced by gamma-irradiation of some dry medical herbs

Energy Technology Data Exchange (ETDEWEB)

Yordanov, N.D. [Laboratory EPR, Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria)], E-mail: ndyepr@bas.bg; Lagunov, O. [Laboratory EPR, Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Dimov, K. [Institute of Cryobiology and Food technology, 1162 Sofia (Bulgaria)

2009-04-15

The radiation-induced EPR spectra in some medical herbs are reported. The samples studied are: (i) leaves of nettle, common balm, peppermint and thyme; (ii) stalks of common balm, thyme, milfoil, yarrow and marigold; (iii) blossoms of yarrow and marigold; (iv) blossoms and leaves of hawthorn and tutsan; and (v) roots of common valerian, nettle, elecampane (black and white), restharrows and carlina. Before irradiation all samples exhibit one weak anisotropic singlet EPR line with effective g-value of 2.0050{+-}0.0002. The radiation-induced spectra fall into three groups. EPR spectra of irradiated blossoms of yarrow and marigold, stalks of common balm, thyme, tutsan and yarrow as well as roots of common valerian, nettle and elecampane (black and white) show 'cellulose-like' EPR spectrum typical for irradiated plants. It is characterized by one intense central line with g=2.0050{+-}0.0005 and two weak satellite lines situated ca. 30 G left and right to it. EPR spectra of gamma-irradiated restharrows and carlina are complex. They may be represented by one triplet corresponding to the 'cellulose-like' EPR spectrum, one relatively intense singlet, situated in the center of the spectrum, and five weak additional satellite lines left and right to the center. The last spectrum was assigned as 'carbohydrate-like' type. Only one intense EPR singlet with g=2.0048{+-}0.0005 was recorded after irradiation of leaves of nettle and common balm. The lifetime of the radiation-induced EPR spectra was followed for a period of 3 months.

Molecular mechanisms of induced mutagenesis. Replication in vivo of bacteriophage phiX174 single-stranded, ultraviolet light-irradiated DNA in intact and irradiated host cells

Energy Technology Data Exchange (ETDEWEB)

Caillet-Fauquet, P; Defais, M; Radman, M [Brussels Univ. (Belgium)

1977-11-25

Genetic analysis has revealed that radiation and many chemical mutagens induce in bacteria an error-prone DNA repair process which is responsible for their mutagenic effect. The biochemical mechanism of this inducible error-prone repair has been studied by analysis of the first round of DNA synthesis on ultraviolet light-irradiated phiX174 DNA in both intact and ultraviolet light-irradiated host cells. Intracellular phiX174 DNA was extracted, subjected to isopycnic CsCl density-gradient analysis, hydroxylapatite chromatography and digestion by single-strand-specific endonuclease S/sub 1/. Ultraviolet light-induced photolesions in viral DNA cause a permanent blockage of DNA synthesis in intact Escherichia coli cells. However, when host cells were irradiated and incubated to induce fully the error-prone repair system, a significant fraction of irradiated phiX174 DNA molecules can be fully replicated. Thus, inducible error-prone repair in E.coli is manifested by an increased capacity for DNA synthesis on damaged phiX174 DNA. Chloramphenicol (100 ..mu.. g/ml), which is an inhibitor of the inducible error-prone DNA repair, is also an inhibitor of this particular inducible DNA synthesis.

A small angle neutron study of irradiation induced microstructures in Cr-Mo-V WWER steels

International Nuclear Information System (INIS)

Levit, Vladimir I.; Santos, Ari S.; Louzada, Ana R.R.; Silveira, Cristina M.; Vaniel, Ana Paula H.; Odette, George R.; Mader, Eric

2000-01-01

Small angle neutron scattering (SANS) has proven to be a very effective technique for characterizing the ultrafine (∼1 nm) irradiation induced microstructures which are responsible for hardening and the concomitant embrittlement of reactor pressure vessel steels. SANS measurement were carried out on three irradiated and unirradiated weld materials of WWER- type on 8 m instrument at the National Institute of Standards and Technology, Washington, USA. Small (r m < 1 nm) irradiation induced features were found for all three materials. Were found volume fractions, number densities and ratios of magnetic to nuclear scattering. Some analyses of the irradiation induced precipitation nature and possible chemical composition were made by comparison of the results with other reactor materials SANS and Atom Probe Field Ion Microscopy data. (author)

Effect of irradiation on analgesia induced by morphine and endorphin

International Nuclear Information System (INIS)

Kim, Jin Kyu; Lee, Byoung Hun; Hyun, Soung Hee; Chung, Ki Myung

2003-01-01

Morphine and endorphin administered intracerebroventricularly (i.c.v.) produce analgesia by activating different descending pain inhibitory systems. Gamma irradiation attenuates the acute analgesic action of i.c.v. injected morphine in mice. This study was done to investigate the effect of-irradiation on the analgesia produced by i.c.v. injected morphine and endorphin in male ICR mice. In one group, mice were exposed to whole-body irradiation at a dose of 5 Gy from a 60 Co source and the analgesic effects were tested 5, 30, 60, 90 and 180 min after irradiation using the acetic acid-induced writhing test. The analgesic effect was produced time-dependently and reached its maximum at 90 min after irradiation. Thus, time was fixed in the following studies. In another group, mice were irradiated with 5 Gy and tested 90 minutes later for analgesia produced by i.c.v. administration of morphine or endorphin. Irradiation significantly potentiated the analgesia produced by endorphin. However, the antinociception produced by morphine was not affected by irradiation. These results support the hypothesis that morphine and endorphin administered supraspinally produce antinocieception by different neuronal mechanisms

Effect of irradiation on analgesia induced by morphine and endorphin

Energy Technology Data Exchange (ETDEWEB)

Kim, Jin Kyu; Lee, Byoung Hun; Hyun, Soung Hee; Chung, Ki Myung [KAERI, Daejeon (Korea, Republic of)

2003-07-01

Morphine and endorphin administered intracerebroventricularly (i.c.v.) produce analgesia by activating different descending pain inhibitory systems. Gamma irradiation attenuates the acute analgesic action of i.c.v. injected morphine in mice. This study was done to investigate the effect of-irradiation on the analgesia produced by i.c.v. injected morphine and endorphin in male ICR mice. In one group, mice were exposed to whole-body irradiation at a dose of 5 Gy from a {sup 60}Co source and the analgesic effects were tested 5, 30, 60, 90 and 180 min after irradiation using the acetic acid-induced writhing test. The analgesic effect was produced time-dependently and reached its maximum at 90 min after irradiation. Thus, time was fixed in the following studies. In another group, mice were irradiated with 5 Gy and tested 90 minutes later for analgesia produced by i.c.v. administration of morphine or endorphin. Irradiation significantly potentiated the analgesia produced by endorphin. However, the antinociception produced by morphine was not affected by irradiation. These results support the hypothesis that morphine and endorphin administered supraspinally produce antinocieception by different neuronal mechanisms.

A phase field model for segregation and precipitation induced by irradiation in alloys

Science.gov (United States)

Badillo, A.; Bellon, P.; Averback, R. S.

2015-04-01

A phase field model is introduced to model the evolution of multicomponent alloys under irradiation, including radiation-induced segregation and precipitation. The thermodynamic and kinetic components of this model are derived using a mean-field model. The mobility coefficient and the contribution of chemical heterogeneity to free energy are rescaled by the cell size used in the phase field model, yielding microstructural evolutions that are independent of the cell size. A new treatment is proposed for point defect clusters, using a mixed discrete-continuous approach to capture the stochastic character of defect cluster production in displacement cascades, while retaining the efficient modeling of the fate of these clusters using diffusion equations. The model is tested on unary and binary alloy systems using two-dimensional simulations. In a unary system, the evolution of point defects under irradiation is studied in the presence of defect clusters, either pre-existing ones or those created by irradiation, and compared with rate theory calculations. Binary alloys with zero and positive heats of mixing are then studied to investigate the effect of point defect clustering on radiation-induced segregation and precipitation in undersaturated solid solutions. Lastly, irradiation conditions and alloy parameters leading to irradiation-induced homogeneous precipitation are investigated. The results are discussed in the context of experimental results reported for Ni-Si and Al-Zn undersaturated solid solutions subjected to irradiation.

A phase field model for segregation and precipitation induced by irradiation in alloys

International Nuclear Information System (INIS)

Badillo, A; Bellon, P; Averback, R S

2015-01-01

A phase field model is introduced to model the evolution of multicomponent alloys under irradiation, including radiation-induced segregation and precipitation. The thermodynamic and kinetic components of this model are derived using a mean-field model. The mobility coefficient and the contribution of chemical heterogeneity to free energy are rescaled by the cell size used in the phase field model, yielding microstructural evolutions that are independent of the cell size. A new treatment is proposed for point defect clusters, using a mixed discrete-continuous approach to capture the stochastic character of defect cluster production in displacement cascades, while retaining the efficient modeling of the fate of these clusters using diffusion equations. The model is tested on unary and binary alloy systems using two-dimensional simulations. In a unary system, the evolution of point defects under irradiation is studied in the presence of defect clusters, either pre-existing ones or those created by irradiation, and compared with rate theory calculations. Binary alloys with zero and positive heats of mixing are then studied to investigate the effect of point defect clustering on radiation-induced segregation and precipitation in undersaturated solid solutions. Lastly, irradiation conditions and alloy parameters leading to irradiation-induced homogeneous precipitation are investigated. The results are discussed in the context of experimental results reported for Ni–Si and Al–Zn undersaturated solid solutions subjected to irradiation. (paper)

Gamma Irradiation Induced Degradation of Orange Peels

Directory of Open Access Journals (Sweden)

Jaime Saucedo Luna

2012-08-01

Full Text Available In this study, gamma irradiation induced degradation of orange peels (OP was investigated. The lignocellulosic biomass degradation was carried out at doses of 0 (control, 600, 1800 and 3500 kGy using a Co-60 gamma radiation source. The samples were tested for total and reducing sugars. The concentrations of total sugars ranged from 0.530 g∙g⁻¹ in control sample to 0.382 g∙g⁻¹ of dry weight in the sample which received the highest radiation dose. The reducing sugars content varying from 0.018 to 0.184 g∙g⁻¹ of dry weight with the largest rise occurring in the sample irradiated at 3500 kGy. The concentrations of sucrose, glucose and fructose were determined. The changes generated in physico-chemical properties were determined by Fourier Transform Infrared Spectroscopy (FTIR and termogravimetric analysis (TG-DTG. The results show that OP was affected, but not significantly, which suggests that lignocellulose and sugars profiles were partially degraded after gamma irradiation.

Study on cellular survival adaptive response induced by low dose irradiation of 153Sm

International Nuclear Information System (INIS)

Zhu Shoupeng; Xiao Dong

1999-01-01

The present study engages in determining whether low dose irradiation of 153 Sm could cut down the responsiveness of cellular survival to subsequent high dose exposure of 153 Sm so as to make an inquiry into approach the protective action of adaptive response by second irradiation of 153 Sm. Experimental results indicate that for inductive low dose of radionuclide 153 Sm 3.7 kBq/ml irradiated beforehand to cells has obvious resistant effect in succession after high dose irradiation of 153 Sm 3.7 x 10 2 kBq/ml was observed. Cells exposed to low dose irradiation of 153 Sm become adapted and therefore the subsequent cellular survival rate induced by high dose of 153 Sm is sufficiently higher than high dose of 153 Sm merely. It is evident that cellular survival adaptive response could be induced by pure low dose irradiation of 153 Sm only

Radioprotective effects of chlorogenic acid against mortality induced by gamma irradiation in mice

International Nuclear Information System (INIS)

Seyed Jalal Hosseinimehr; Amirhossein Ahmadi; Shahram Akhlaghpoor; Tehran University of Medical Sciences, Tehran

2007-01-01

Complete text of publication follows. The radioprotective effects of the naturally occurring compound chlorogenic acid has been investigated against mortality induced by gamma irradiation in mice. Chlorogenic acid administrated at single doses of 100, 200 and 400 mg/kg 1 and 24 h prior to lethal dose of gamma irradiation (8.5 Gy). At 30 days after treatment, the percentage of animal survival in each group was: control, 20%; 100 mg/kg, 20% and 15%; 200 mg/kg, 45% and 15%; 400 mg/kg, 25% and 35% for 1 h and 24 h treatment prior gamma irradiation, respectively. Percentage of survival increased in animal treated with this agent at 200 mg/kg at 1 h statistically compared with irradiated alone group. Other doses of chlorogenic acid have not showed any enhanced survival at 1 and 24 h before irradiation. Chlorogenic acid exhibited concentration-dependent activity on 1, 1-diphenyl 2-picrylhydrazyl free radical to show strong antioxidant activity. It appeared that chlorogenic acid with antioxidant activity reduced mortality induced by gamma irradiation.

Evaluation of induced radioactivity in 10 MeV-Electron irradiated spices, (2)

International Nuclear Information System (INIS)

Katayama, Tadashi; Furuta, Masakazu; Shibata, Setsuko; Matsunami, Tadao; Ito, Norio; Mizohata, Akira; Toratani, Hirokazu; Takeda, Atsuhiko.

1994-01-01

In order to check radioactivity of beta-emmitters produced by (γ, n) reactions which could occur at energies up to 10 MeV, black pepper, white pepper, red pepper, ginger and turmeric were irradiated with 10 MeV electron from a linear accelerator to a dose of 100 kGy. Beta-rays were counted using a 2π gas flow counter and a liquid scintillation counter. Any induced radioactivity could not be detected in irradiated samples. When inorganic compounds containing the nuclides in the list were artificially added in the samples and were irradiated, the β-activities were detected. From the amount of observed radioactivities of β-emmitters produced in the compounds as photonuclear products, it is concluded that the induced radioactivity in natural samples by 10 MeV-electron irradiation were far smaller than natural radioactivity from 40 K contained in the samples and, hence, its biological effects should be negligible. (author)

Response of stem cell system to whole body and partial body irradiation

International Nuclear Information System (INIS)

Gidali, J.

1975-01-01

The pluripotent stem cell system, though being distributed in the body, reacts homogeneously to irradiation. This homogeneity is controlled by short-range (local) and long-range (humoral) regulations acting primarily on pluripotent and committed stem cells. Migration of stem cells from unirradiated to irradiated areas may play a role in the regeneration processes even if local regeneration may also occur. Migration induction as well as proliferation induction in the shielded area do not seem to be specific radiation-induced reactions. Both may be influenced either by some physiological regulators released after irradiation in a higher quantity or by some non-specific triggering agents. Both repeated and continuous irradiation induce the establishment of a new steady state. In the steady state after repeated sublethal irradiations, the CFU count stays at a suboptimal level either as a consequence of an increased differentiation or of some undefined damage in milieu control. In the new steady state during continuous irradiation, the number of mature elements in blood is close to the normal while CFU population is reduced to less than 2 percent of its original level

Locally advanced prostatic cancer: experience with combined pelvic external beam irradiation and interstitial thermobrachytherapy

Energy Technology Data Exchange (ETDEWEB)

Hancock, Steven L; Kapp, Daniel S; Goffinet, Don R; Prionas, Stavros; Cox, Richard S; Bagshaw, Malcolm A

1995-07-01

Purpose: Recurrence of prostatic carcinoma within the prostate gland remains a significant problem for patients who present with locally advanced disease. In an attempt to improve the local control of such tumors, an iridium-192 transperineal, template-guided prostatic implant was combined wit radiofrequency-induced hyperthermia after external beam irradiation of the pelvic lymph nodes and prostate gland. This study evaluates the influence of pre-treatment patient characteristics and treatment parameters upon outcome. Materials and Methods: Between July 1987 and April 1992 33 patients with adenocarcinoma of the prostate were selected for treatment: 28 of these patients had extensive local disease on clinical examination (AJCC-4 stages T2b or c: 9 patients; T3: 19 patients); two patients with T2a tumors had Gleason grade 5 + 4 disease or disproportionately high prostate specific antigen (PSA) values and a mass encroaching upon the bladder on computerized tomographic scan. Three patients with more clinically limited T2a or T2b involvement elected implantation in lieu of an external beam irradiation boost. The mean pre-treatment serum PSA value was 25.6 ng/ml (Hybritech scale), with values of above 19 ng/ml for 17 of the patients. Treatment consisted of 50 Gy of external beam irradiation to the prostate and pelvic lymph nodes followed by a transperineal needle implant of the prostate gland. Thirty-two patients had no evidence of pelvic nodal involvement during exploration at laparotomy performed after external irradiation, and 25 of these had lymph node samplings that were histologically negative for metastasis. Perineal template oriented needles were placed by inspection and palpation at laparotomy; 2 were performed closed under ultrasound guidance. Needles were afterloaded with {sup 192}Ir to provide a dose of 30 Gy to the periphery of the prostate gland. Interstitial radiofrequency-induced hyperthermia treatments were given in conjunction with the implant, one just

Heat-shock-induced enhanced reactivation of UV-irradiated Herpesvirus

Energy Technology Data Exchange (ETDEWEB)

Yager, J.D.; Zurlo, J.; Penn, A.L.

1985-09-01

The objective of this study was to compare the ability of heat shock (HS) with that of another type of cellular stress, UV irradiation, to cause the induction of enhanced viral reactivation, a process that may represent an SOS-type repair process in mammalian cells. These results indicate that, like UV irradiation, HS at levels inhibitory to cell growth induced enhanced viral reactivation in Vero cells. The results also suggest that at least two proteins in the HS protein family are not necessary for this response to occur. (Auth.). 27 refs.; 5 figs.

Modeling of cavity swelling-induced embrittlement in irradiated austenitic stainless steels

International Nuclear Information System (INIS)

Han, X.

2012-01-01

During long-time neutron irradiation occurred in Pressurized Water Reactors (PWRs), significant changes of the mechanical behavior of materials used in reactor core internals (made of 300 series austenitic stainless steels) are observed, including irradiation induced hardening and softening, loss of ductility and toughness. So far, much effect has been made to identify radiation effects on material microstructure evolution (dislocations, Frank loops, cavities, segregation, etc.). The irradiation-induced cavity swelling, considered as a potential factor limiting the reactor lifetime, could change the mechanical properties of materials (plasticity, toughness, etc.), even lead to a structure distortion because of the dimensional modifications between different components. The principal aim of the present PhD work is to study qualitatively the influence of cavity swelling on the mechanical behaviors of irradiated materials. A micromechanical constitutive model based on dislocation and irradiation defect (Frank loops) density evolution has been developed and implemented into ZeBuLoN and Cast3M finite element codes to adapt the large deformation framework. 3D FE analysis is performed to compute the mechanical properties of a polycrystalline aggregate. Furthermore, homogenization technique is applied to develop a Gurson-type model. Unit cell simulations are used to study the mechanical behavior of porous single crystals, by accounting for various effects of stress triaxiality, of void volume fraction and of crystallographic orientation, in order to study void effect on the irradiated material plasticity and roughness at polycrystalline scale. (author) [fr

Tocopherol in irradiation of temporary hypoxic tumours

International Nuclear Information System (INIS)

Kaagerud, A.; Lund, N.; Peterson, H.I.

1981-01-01

The influence of tocopherol on the effect of local irradiation under induced ischaemia by temporary tourniquet of two rat tumours transplanted intramuscularly into one hindleg was evaluated. An impaired retardation of growth rate occurred in tumours irradiated under ischaemia. This effect was eliminated by pretreatment of animals with tocopherol. In separate experiments the method of inducing ischaemia was investigated by MDO-electrode measurements of tumour tissue oxygen pressure. A significant tumour hypoxia was found under tourniquet of the tumour-bearing leg of the animals. Pretreatment with tocopherol did not influence the tumour pO 2 . (Auth.)

Medium from X-rayed cultures induces DNA strand-breaks in non-irradiated HeLa cells

International Nuclear Information System (INIS)

Ikushima, T.; Okuyama, K.; Tanizaki, Y.

2002-01-01

There is growing evidence to indicate that several types of responses are induced by ionizing radiation in non-irradiated cells. Such bystander effects include the killing of non-irradiated cells, the induction of sister chromatid exchanges and chromosomal aberrations, and the induction of gene mutations and chromosomal instability and enhanced cell growth. In the present study, we assessed whether the medium from irradiated cultures can induce DNA strand-breaks in non-irradiated cells, using single-cell gel electrophoresis assay (comet assay). HeLa cells in culture were irradiated with 0.5 to 8 Gy of 140 kVp X-rays and one hour later, the medium was taken from the irradiated culture, passed through a filter and transferred to the parallel culture of non-irradiated HeLa cells as non-target cells. After incubation for 30 min, the comet assay was performed under alkaline and neutral conditions. Such treatments resulted in a dose-dependent increase in tail moment under either alkaline or neutral condition, indicating the induction of DNA single- or double-strand breaks, respectively. It was also shown that the clonogenic survival was reduced in the cells cultured in the medium from irradiated cultures. Such a change was not detected at all when medium alone was irradiated. These results provided disputed evidence that irradiated cells released certain genotoxic factor(s) into the culture medium that can induce DNA strand breaks leading to cell death. Our results suggest that physical contact between irradiated and non-irradiated cells may not be necessary for the bystander effects observed in this study. It appears that bystander responses may be mediated by multiple mechanisms

Radiation-induced systemic and local bone tumors: Two types of late effects with possible different origins?

International Nuclear Information System (INIS)

Mueller, W.A.; Luz, A.; Linzner, U.

1994-01-01

Bone sarcomas may be induced throughout the skeleton (systemic) in mice by relatively low internal α-particle doses that are distributed over the whole skeleton. The induction of local (periosteal) bone sarcomas after paratibial deposition of insoluble radiocolloids required much higher doses, and in addition high energies of emitted particles. Paratibial deposition of α-particle-emitting radiocolloids of 227 Th and 228 Th resulted in formation of both local and systemic bone sarcomas. The latter were most probably induced by the released radium daughters of the thorium isotopes and were distributed about the skeleton. Paratibial injections with β-particle emitters 144 Ce+ 144 Pr (29 kBq per mouse) showed an incidence of local bone sarcomas of more than 80%. An estimation of the local effective doses led to values of more than 1000 Gy for the β-particle emitter 144 Ce and around 150 Gy for the thorium isotopes. Thus induction of local bone sarcomas required doses considerably greater than those needed for systemic bone sarcomas. The local induction of bone sarcomas has been reported for high-energy β particles using similar high doses of 144 Ce+ 144 Pr in rats and for external 90 Sr+ 90 Y irradiation in mice. We conclude that the processes involved in the induction of local and systemic bone sarcomas by radiation may be quite different. 35 refs., 1 fig., 3 tabs

Effect of irradiation on unscheduled DNA synthesis induced by 4-nitroquinoline in tracheal epithelium of rats

International Nuclear Information System (INIS)

Hahn, F.F.; Kennedy, R.; Brooks, A.L.

1986-01-01

Unscheduled DNA synthesis (UDS) was determined in rat epithelium by autoradiographic techniques to determine the influence of prior irradiation on the ability of the cells to repair mutagenic damage induced by 4-nitroquionoline (4NQO). UDS was stimulated by in vitro exposure to 4NPO. However, prior whole-body irradiation of rats with either 50 or 300 rad did not alter the UDS induced by 4NQO. The results of this study do not support the hypothesis that irradiation can induce DNA repair enzymes in respiratory tract epithelium. 5 references, 3 figures

Analysis of radicals induced in irradiated cereal flour using ESR

International Nuclear Information System (INIS)

Kawamura, Shoei; Kishita, Keigo; Ukai, Mitsuko; Kikuchi, Masahiro; Kobayashi, Yasuhiko

2013-01-01

Using electron spin resonance (ESR) spectroscopy, we revealed radicals induced in cereal flour irradiated with gamma-ray or electron beam. Sample was wheat and rice. We detected a broad singlet signal at g = 2.0. It consists of a singlet signal and a triplet signal. It suggested that the singlet signal is originated from organic free radicals and the triplet signal is from 14 N. There were no differences of ESR spectra between irradiated wheat flour and rice flour. The signal intensity of radiation induced radical was tend to increase following with the increase of radiation dose level. After radiation treatment, relaxation time of radiation induced radical was changed during storage. T 1 was decreased and T 2 was increased. In this study, the relaxation time is calculated using the parameters obtained from the ESR signal. It is necessary to analyze the relaxation time directly with pulsed ESR spectroscopy in future. (author)

Tocopherol in irradiation of experimental neoplasms

International Nuclear Information System (INIS)

Kaagerud, A.; Peterson, H.-I.

1981-01-01

The influence of tocopherol, administered intramuscularly in different single doses, on the effect of local irradiation of a transplanted rat sarcoma was investigated. Tocopherol in doses of 5, 25 or 50 mg/100 g body weight enhanced significantly the tumour growth retardation induced by irradiation. Tocopherol in a dose of 100 mg/100 g body weight as a placebo preparation had no similar effect. The influence of tocopherol administered intramuscularly or orally in identical doses was similar. (Auth.)

Ultraviolet B irradiation of human leukaemia HL-60 cells in vitro induces apoptosis

International Nuclear Information System (INIS)

Martin, S.J.; Cotter, T.G.

1991-01-01

UV radiation is known to be a potent agent for the induction of programmed cell death (apoptosis) in human skin. However, the mechanistic aspects of UV-induced apoptosis remain ill-defined. In this study the effects of varying periods of UV-irradiation on the human leukaemia HL-60 cell line and on five other human cell lines were investigated.HL-60 cells were found to rapidly undergo apoptosis en masse after short periods of UV-irradiation whereas prolonged exposure of these cells to this form of radiation induced a more rapid form of cell death which was suggestive of necrosis, the pathological mode of cell death. UV-induced apoptosis in cell lines was characterized by morphological changes as well as DNA fragmentation into unit multiples of ∼ 200 bp, which was indicative of endogenous endonuclease activation. This DNA fragmentation pattern was not detected in cells immediately after UV-irradiation, and was therefore not the result of direct UV-induced DNA damage. UV-induced apoptosis of the HL-60 cell line was found to require extracellular calcium and to be inhibited in a dose-dependent way by zinc added to the culture medium. (author)

Effect of localized intraoperative x-rays irradiation followed by intermittent external exposure on certain histochemical parameters related to pancreatic function

International Nuclear Information System (INIS)

Abdel-Azeem, M.G.

2005-01-01

The present study was carried out to evaluate the pancreatic enzyme activities in rabbits, whose splenic part of pancreas was exposed to local intraoperative radiation therapy (IORT) at level of 30 Gy X-rays followed by fractionated external radiation therapy (ERT) at a total dose of 40 Gy (2 Gy day after day) starting from the 15th day following the local intraoperative irradiation. The control pancreas was that received only external X-rays radiation without local irradiation. The exocrine pancreatic functions were assessed by determination of insulin hormone and enzyme activity of lipase as well as alkaline and acid phosphatases. After local X-rays irradiation on days 2 and 10 and after external X-rays irradiation on days 23 , 33 , 43 and 53, technovit-8100 plastic embedding (Kulzer and Heraeus) was used to prepare the cold blocks. The quantitative morphometric method was used to evaluate the histochemical pancreatic activity of the irradiated and control pancreas of each rabbit. Most of the studied parameters recorded non-significant changes as a result of the applied different levels of X-rays irradiation, which would give the chance to use this type of irradiation in pancreatic radiotherapy without any hazards to the pancreas

Compositional changes in industrial hemp biomass (Cannabis sativa L.) induced by electron beam irradiation Pretreatment

International Nuclear Information System (INIS)

Sung, Yong Joo; Shin, Soo-Jeong

2011-01-01

The effects of electron beam irradiation on chemical decomposition of industrial hemp biomass were evaluated at doses of 150, 300, and 450 kGy. The quantity of decomposed components was indirectly estimated by measuring changes in alkaline extraction. The more severe degradation of structural components induced by higher irradiation doses resulted in larger amounts of alkaline extract. Carbohydrate compositional analysis using 1 H-NMR spectroscopy was applied to quantitatively investigate changes in the polysaccharides of the industrial hemp. The xylose peak intensity in the NMR spectra decreased with increasing electron irradiation dose, indicating that xylan was more sensitive to electron beam irradiation than cellulose. -- Highlights: → The more severe degradation of structural components induced by higher irradiation. → Carbohydrate analysis was applied to quantitatively investigate changes in the industrial hemp. → Xylan was more sensitive to electron beam irradiation than cellulose.

Compositional changes in industrial hemp biomass (Cannabis sativa L.) induced by electron beam irradiation Pretreatment

Energy Technology Data Exchange (ETDEWEB)

Sung, Yong Joo [Department of Biobased Materials, College of Agriculture and Life Science, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Shin, Soo-Jeong [Department of Wood and Paper Science, College of Agriculture and Life Science, Chungbuk National University, Cheongju 361-763 (Korea, Republic of)

2011-07-15

The effects of electron beam irradiation on chemical decomposition of industrial hemp biomass were evaluated at doses of 150, 300, and 450 kGy. The quantity of decomposed components was indirectly estimated by measuring changes in alkaline extraction. The more severe degradation of structural components induced by higher irradiation doses resulted in larger amounts of alkaline extract. Carbohydrate compositional analysis using {sup 1}H-NMR spectroscopy was applied to quantitatively investigate changes in the polysaccharides of the industrial hemp. The xylose peak intensity in the NMR spectra decreased with increasing electron irradiation dose, indicating that xylan was more sensitive to electron beam irradiation than cellulose. -- Highlights: {yields} The more severe degradation of structural components induced by higher irradiation. {yields} Carbohydrate analysis was applied to quantitatively investigate changes in the industrial hemp. {yields} Xylan was more sensitive to electron beam irradiation than cellulose.

Evaluation of induced radioactivity in 10 MeV-electron irradiated spices, (1); [gamma]-ray measurement

Energy Technology Data Exchange (ETDEWEB)

Furuta, Masakazu; Katayama, Tadashi; Ito, Norio; Mizohata, Akira; Matsunami, Tadao; Shibata, Setsuko; Toratani, Hirokazu (Osaka Prefectural Univ., Sakai (Japan). Research Inst. for Advanced Science and Technology); Takeda, Atsuhiko

1994-02-01

Black pepper, white pepper, red pepper, ginger and turmeric were irradiated with 10 MeV electrons from a linear accelerator to a dose of 100 kGy and radioactivity was measured in order to estimate induced radioactivity in the irradiated foods. Induced radioactivity could not be detected significantly by [gamma]-ray spectrometry in the irradiated samples except for spiked samples which contain some photonuclear target nuclides in the list of photonuclear reactions which could produce radioactivity below 10 MeV. From the amount of observed radioactivities of short-lived photonuclear products in the spiked samples and calculation of H[sub 50] according to ICRP Publication 30, it was concluded that the induced radioactivity and its biological effects in the 10 MeV electron-irradiated natural samples were negligible in comparison with natural radioactivity from [sup 40]K contained in the samples. (author).

Combined treatment of the immunoconjugate bivatuzumab mertansine and fractionated irradiation improves local tumour control in vivo

International Nuclear Information System (INIS)

Gurtner, Kristin; Hessel, Franziska; Eicheler, Wolfgang; Dörfler, Annegret; Zips, Daniel; Heider, Karl-Heinz; Krause, Mechthild; Baumann, Michael

2012-01-01

Background and purpose: To test whether BIWI 1 (bivatuzumab mertansine), an immunoconjugate of the humanized anti-CD44v6 monoclonal antibody BIWA 4 and the maytansinoid DM1, given simultaneously to fractionated irradiation improves local tumour control in vivo compared with irradiation alone. Material and methods: For growth delay, FaDu tumours were treated with 5 intravenous injections (daily) of phosphate buffered saline (PBS, control), BIWA 4 (monoclonal antibody against CD44v6) or BIWI 1 (bivatuzumab mertansine) at two different dose levels (50 μg/kg DM1 and 100 μg/kg DM1). For local tumour control, FaDu tumours received fractionated irradiation (5f/5d) with simultaneous PBS, BIWA 4 or BIWI 1 (two dose levels). Results: BIWI 1 significantly improved local tumour control after irradiation with 5 fractions already in the lower concentration. The dose modifying factor of 1.9 is substantial compared to the majority of other modifiers of radiation response. Conclusion: Because of the magnitude of the curative effect, this approach is highly promising and should be further evaluated using similar combinations with improved tumour-specificity.

Inhomogeneous strain induced by fast neutron irradiation in NaKSO/sub 4/ crystals

Energy Technology Data Exchange (ETDEWEB)

Kandil, S.H.; Kassem, M.E.; El-Khatib, A.; El-Gamal, M.A.; El-Wahidy, E.F.

1987-11-01

The paper reports the effect of fast neutron irradiation on the thermal properties of NaKSO/sub 4/ crystals in the temperature range 400-475 K. Results are presented for the thermal expansion, tensile strain and specific heat of NaKSO/sub 4/, as a function of neutron irradiation dose. All these results revealed an inhomogeneous strain induced by the radiation. It is suggested that this induced inhomogeneous strain could be used to detect neutron exposure doses.

Effect of interaction between irradiation-induced defects and intrinsic defects in the pinning improvement of neutron irradiated YBaCuO sample

International Nuclear Information System (INIS)

Topal, Ugur; Sozeri, Huseyin; Yavuz, Hasbi

2004-01-01

Interaction between the intrinsic (native) defects and the irradiation-induced defects created by neutron irradiation was examined for the YBCO sample. For this purpose, non-superconducting Y-211 phase was included to the Y-123 samples at different contents as a source of large pinning center. The critical current density enhancement with the irradiation for these samples were analysed and then the role of defects on pinning improvement was discussed

Effect of interaction between irradiation-induced defects and intrinsic defects in the pinning improvement of neutron irradiated YBaCuO sample

Energy Technology Data Exchange (ETDEWEB)

Topal, Ugur; Sozeri, Huseyin; Yavuz, Hasbi

2004-08-01

Interaction between the intrinsic (native) defects and the irradiation-induced defects created by neutron irradiation was examined for the YBCO sample. For this purpose, non-superconducting Y-211 phase was included to the Y-123 samples at different contents as a source of large pinning center. The critical current density enhancement with the irradiation for these samples were analysed and then the role of defects on pinning improvement was discussed.

High-dose irradiation induces cell cycle arrest, apoptosis, and developmental defects during Drosophila oogenesis.

Directory of Open Access Journals (Sweden)

Hee Jin Shim

Full Text Available Ionizing radiation (IR treatment induces a DNA damage response, including cell cycle arrest, DNA repair, and apoptosis in metazoan somatic cells. Because little has been reported in germline cells, we performed a temporal analysis of the DNA damage response utilizing Drosophila oogenesis as a model system. Oogenesis in the adult Drosophila female begins with the generation of 16-cell cyst by four mitotic divisions of a cystoblast derived from the germline stem cells. We found that high-dose irradiation induced S and G2 arrests in these mitotically dividing germline cells in a grp/Chk1- and mnk/Chk2-dependent manner. However, the upstream kinase mei-41, Drosophila ATR ortholog, was required for the S-phase checkpoint but not for the G2 arrest. As in somatic cells, mnk/Chk2 and dp53 were required for the major cell death observed in early oogenesis when oocyte selection and meiotic recombination occurs. Similar to the unscheduled DNA double-strand breaks (DSBs generated from defective repair during meiotic recombination, IR-induced DSBs produced developmental defects affecting the spherical morphology of meiotic chromosomes and dorsal-ventral patterning. Moreover, various morphological abnormalities in the ovary were detected after irradiation. Most of the IR-induced defects observed in oogenesis were reversible and were restored between 24 and 96 h after irradiation. These defects in oogenesis severely reduced daily egg production and the hatch rate of the embryos of irradiated female. In summary, irradiated germline cells induced DSBs, cell cycle arrest, apoptosis, and developmental defects resulting in reduction of egg production and defective embryogenesis.

Schisandrin B protects against solar irradiation-induced oxidative injury in BJ human fibroblasts.

Science.gov (United States)

Chiu, Po Yee; Lam, Philip Y; Yan, Chung Wai; Ko, Kam Ming

2011-06-01

The effects of schisandrin B (Sch B) and its analogs on solar irradiation-induced oxidative injury were examined in BJ human fibroblasts. Sch B and schisandrin C (Sch C) increased cellular reduced glutathione (GSH) level and protected against solar irradiation-induced oxidative injury. The photoprotection was paralleled by decreases in the elastases-type protease activity and matrix-metalloproteinases-1 expression in solar-irradiated fibroblasts. The cytochrome P-450-mediated metabolism of Sch B or Sch C caused ROS production. The results suggest that by virtue of its pro-oxidant action and the subsequent glutathione antioxidant response, Sch B or Sch C may offer the prospect of preventing skin photo-aging. Copyright © 2011 Elsevier B.V. All rights reserved.

The evolution of mechanical property change in irradiated austenitic stainless steels

International Nuclear Information System (INIS)

Lucas, G.E.

1993-01-01

The evolution of mechanical properties in austenitic stainless steels during irradiation is reviewed. Changes in strength, ductility and fracture toughness are strongly related to the evolution of the damage microstructure and microstructurally-based models for strengthening reasonably correlate the data. Irradiation-induced defects promote work softening and flow localization which in turn leads to significant reductions in ductility and fracture toughness beyond about 10 dpa. The effects of irradiation on fatigue appear to be modest except at high temperature where helium embrittlement becomes important. The swelling-independent component of irradiation creep strain increases linearly with dose and is relatively insensitive to material variables and irradiation temperature, except at low temperatures where accelerated creep may occur as a result of low vacancy mobility. Creep rupture life is a strong function of helium content, but is less sensitive to metallurgical conditions. Irradiation-induced stress corrosion cracking appears to be related to the evolution of radiation-induced segregation/depletion at grain boundaries, and hence may not be significant at low irradiation temperatures. (orig.)

Studies on rate equations for defects in irradiated solids using the local analysis method

International Nuclear Information System (INIS)

Carvalho e Camargo, M.U. de.

1983-10-01

The void formation and swelling phenomenon in material for nuclear reactors structures, mainly for fast reactors, has been studied by several authors. A simple calculation covering the basic instance of radiation damage in irradiated solid solution, using the local analysis in rate theory is presented here. A simple description of pratical and fundamental interest for the complex problem of solid solution under irradiation is given. (Author) [pt

Study of cancer-specific chimeric promoters induced by irradiation

International Nuclear Information System (INIS)

Xiong Jie; Zhou Yunfeng; Sun Wenjie; Wang Weifeng; Liao Zhengkai; Zhou Fuxiang; Xie Conghua

2010-01-01

Objective: To combine the radio-inducible CArG element with cancer-specific human telomerase reverse transcriptase (hTERT) gene promoter, and to construct the novel chimeric promoters. Methods: The synthetic hTERT promoters containing different number of radio-inducible CArG elements were constructed, and the activities of the promoters in the cancer cells (HeLa, A549, and MHCC97 cells) and nomal cells (hEL cells) were detected by using luciferase-reporter assays after the treatment of irradiation (a single or fractionated irradiation dose). Results: Synthetic promoter containing 6 repeated CArG units was better in radio-inducibility than any other promoters containing different number of CArG units, and nearly maximum levels obtained at 4-6 Gy. The very low activities of the chimeric promoters could be detected in normal hEL cells. A similar level of reporter gene expression was observed after 3 fractionated doses of 2 Gy compared with a single dose of 6 Gy in cancer cells. Conclusions: The cancer-specific chimeric promoter containing 6 CArG elements showes the best radio-response, and the chimeric promoter system has the potential in cancer gene therapy. (authors)

X-irradiation-induced nuclear lesions in cultured mammaliam cells: an ultrastructural analysis

International Nuclear Information System (INIS)

Barham, S.S.; Walters, R.A.

1978-01-01

Electron-dense chromatin aggregates, hereafter referred to as lesions, have been characterized morphologically within interphase nuclei of Chinese hamster cells (line CHO) after a single acute exposure to 400, 800, 1200, or 2000 rad of x irradiation. At all doses studied, lesions were observed only after termination of radiation-induced division delay. Cell profiles were scored by electron microscopy for the presence or absence of nuclear lesions at various times after irradiation. The mitotic fraction from each irradiated population was also scored for each sample by light and electron microscopy. From these data and from simultaneous cell-density counts for each sample, it is apparent that postirradiation cell division is a prerequisite to formation of interphase nuclear lesions. Irradiated cell populations blocked in mitosis by Colcemid beyond the normal period of postirradiation division-delay failed to display nuclear lesions until after Colcemid was removed and cell division was completed. Enzyme digestions of isolated nuclei from irradiated cells with DNase I, RNase A, and Pronase suggest that the nuclear lesions are comprised primarily of chromatin. Nucleolar lesions, as well as various aberrant morphological forms of nucleoli, were also observed in cell populations after the onset of postirradiation cell division during the first 72 hr following exposure to irradiation. Delayed radiation-induced ultrastructural alterations of the nucleus included the formation of cytoplasmic invaginations into the nuclear space and inclusions of membranes within nuclei

Temper embrittlement, irradiation induced phosphorus segregation and implications for post-irradiation annealing of reactor pressure vessels

International Nuclear Information System (INIS)

McElroy, R.J.; English, C.A.; Foreman, A.J.; Gage, G.; Hyde, J.M.; Ray, P.H.N.; Vatter, I.A.

1999-01-01

Three steels designated JPB, JPC and JPG from the IAEA Phase 3 Programme containing two copper and phosphorus levels were pre- and post-irradiation Charpy and hardness tested in the as-received (AR), 1200 C/0.5h heat treated (HT) and heat treated and 450 C/2000h aged (HTA) conditions. The HT condition was designed to simulate coarse grained heat-affected zones (HAZ's) and showed a marked sensitivity to thermal ageing in all three alloys. Embrittlement after thermal ageing was greater in the higher phosphorus alloys JPB and JPG. Charpy shifts due to thermal ageing of between 118 and 209 C were observed and accompanied by pronounced intergranular fracture, due to phosphorus segregation. The irradiation embrittlement response was complex. The low copper alloys, JPC and JPB, in the HT and HTA condition exhibited significant irradiation induced Charpy shift but very low or even negative hardness changes indicating non-hardening embrittlement. The higher copper alloy, JPG, also exhibited irradiation hardening in line with its copper content. Fractographic and microchemical studies indicated irradiation induced phosphorus segregation and a transition from cleavage to intergranular failure at grain boundary phosphorus concentrations above a critical level. The enhanced grain boundary phosphorus level increased with dose in agreement with a kinetic segregation model developed at Harwell. The relevance of the thermal ageing studies to RPV Annealing for Plant-Life Extension was identified early in the program. It is of concern that annealing of RPV's has been performed, or is proposed, at temperatures in the range 425--475 C for periods of about 1 week (168h). Much attention has been given to the use of in-situ hardness measurements and machining miniature Charpy and tensile specimens from belt-line plate and weld materials. However, HAZ's, often containing higher phosphorus levels than the present materials, have largely been ignored. A post-irradiation annealing (PIA

Fe+ ion irradiation induced changes in structural and magnetic properties of iron films

Directory of Open Access Journals (Sweden)

K. Papamihail

2016-12-01

Full Text Available 490keV Fe+ ion irradiation of 200nm thick Fe films was found to induce both structural and magnetic changes. Both, the lattice constant and the grain size increase as a function of dose and both properties follow the same power law. Irradiation induces a depth dependent magnetic profile consisting of two sublayers. The top Fe sublayer has a magnetic moment higher than that of the Fe before the irradiation whereas the bottom sublayer lower. The two sublayers are connected with the effects of Fe+ irradiation, i.e. the top sublayer with the depth in which mainly radiation damage occurs whereas the bottom one with the implantation of impinging Fe+ ions. The magnetic moments of the two sublayers have a non-monotonous variation with irradiation dose depicting a maximum for the top sublayer and a minimum for the bottom one at 96.2 dpa (‘displacements per atom’. The magnetic moment enhancement/reduction is discussed in relation with the atomic volume variation in the case of atom displacements and/or implantation effects.

A reevaluation of X-irradiation-induced phocomelia and proximodistal limb patterning.

Science.gov (United States)

Galloway, Jenna L; Delgado, Irene; Ros, Maria A; Tabin, Clifford J

2009-07-16

Phocomelia is a devastating, rare congenital limb malformation in which the long bones are shorter than normal, with the upper portion of the limb being most severely affected. In extreme cases, the hands or fingers are attached directly to the shoulder and the most proximal elements (those closest to the shoulder) are entirely missing. This disorder, previously known in both autosomal recessive and sporadic forms, showed a marked increase in incidence in the early 1960s due to the tragic toxicological effects of the drug thalidomide, which had been prescribed as a mild sedative. This human birth defect is mimicked in developing chick limb buds exposed to X-irradiation. Both X-irradiation and thalidomide-induced phocomelia have been interpreted as patterning defects in the context of the progress zone model, which states that a cell's proximodistal identity is determined by the length of time spent in a distal limb region termed the 'progress zone'. Indeed, studies of X-irradiation-induced phocomelia have served as one of the two major experimental lines of evidence supporting the validity of the progress zone model. Here, using a combination of molecular analysis and lineage tracing in chick, we show that X-irradiation-induced phocomelia is fundamentally not a patterning defect, but rather results from a time-dependent loss of skeletal progenitors. Because skeletal condensation proceeds from the shoulder to fingers (in a proximal to distal direction), the proximal elements are differentially affected in limb buds exposed to radiation at early stages. This conclusion changes the framework for considering the effect of thalidomide and other forms of phocomelia, suggesting the possibility that the aetiology lies not in a defect in the patterning process, but rather in progenitor cell survival and differentiation. Moreover, molecular evidence that proximodistal patterning is unaffected after X-irradiation does not support the predictions of the progress zone model.

Elevated sodium chloride concentrations enhance the bystander effects induced by low dose alpha-particle irradiation

International Nuclear Information System (INIS)

Han Wei; Zhu Lingyan; Jiang Erkang; Wang Jun; Chen Shaopeng; Bao Linzhi; Zhao Ye; Xu An; Yu Zengliang; Wu Lijun

2007-01-01

Previous studies have shown that high NaCl can be genotoxic, either alone or combined with irradiation. However, little is known about the relationship between environmental NaCl at elevated conditions and radiation-induced bystander effects (RIBE). RIBE, which has been considered as non-targeted bystander responses, has been demonstrated to occur widely in various cell lines. In the present study, RIBE under the elevated NaCl culture condition was assessed in AG 1522 cells by both the induction of γ-H2AX, a reliable marker of DNA double-strand break (DSB) for the early process ( G -methyl-L-arginine, an inhibitor of nitric oxide synthase, the induced fraction of foci-positive cells was effectively inhibited both in 0.2 cGy α-particle irradiated and adjacent non-irradiated regions under either normal or elevated NaCl conditions. These results suggested that the cultures with elevated NaCl medium magnified the damage effects induced by the low dose α-particle irradiation and nitric oxide generated by irradiation was also very important in this process

Irradiation-induced segregation in multi-component alloys

International Nuclear Information System (INIS)

Chen, I.W.

1983-01-01

A unified analysis of irradiation-induced segregation in multi-component alloys is developed using the formulation of irreversible thermodynamics. Three distinct mechanisms for segregation, namely the inverse Kirkendall effect, the vacancy-wind effect, and the solute drag of interstitials, are identified. In particular, the inverse Kirkendall effect due to interstitials arises only if a solute-interstitial interaction or a mutual conversion among interstitials via lattice atom intermediaries operates simultaneously. In the limit of fast conversion a para-equilibrium state may be reached between interstitials and lattice atoms, and the interstitial mechanism becomes formally analogous to the vacancy mechanism. Although the past treatment of rate phenomena in this field was apparently limited to the latter case, the importance of the consideration of separate chemical potentials for interstitials of different species, in segregation and other irradiation effects, is emphasized. (orig.)

Search for the lowest irradiation dose from literatures on radiation-induced cancer in uterus

International Nuclear Information System (INIS)

Yoshizawa, Yasuo; Kusama, Tomoko

1975-01-01

A survey of past case reports on radiation-induced cancer of the uterus was carried out with the main object of finding the lowest irradiation dose. Search of literature published since 1912 revealed 548 cases of radiation-induced cancer of the uterus. All of these cases of radiation-induced cancer had received radiation for the treatment of non-malignant disease. The primary gynecological conditions which were the object of radiation therapy were functional bleeding, endometrial hyperplasia, myoma, endometritis, and polyps. The lowest irradiation dose was estimated at 1000-1450 rad in the case of external X-ray irradiation, and 100 mg.hr for intrauterine radium therapy, which corresponds to 100-1000 rad. It was noted that were more cases of corpus cancer than cervical cancer. Histopathological findings of radiation-induced uterine cancer were carcinoma, sarcoma, and mixed mesodermal tumors. The latent period was distributed in the range of 1 to 40 years, with the average of 10.1 years. (auth.)

protective effect of combined administration of isoflavones genistein and daidzein against irradiation -induced damage in female rats

International Nuclear Information System (INIS)

Ashry, O.M.

2009-01-01

The renewed interests in the search for plant-derived drugs in the field of alternative medicine necessitate further studies. the present work aimed to evaluate the efficacy of diet phyto estrogens such as diadzein and genistein on repairing oxidative damage and protecting calcium homeostatic system against radiation induced disorders in female rats. soybean isoflavones were orally administered in a dose of 9 mg/kg body wt/day for 21 and 26 days. irradiated animals received diadzein and genistein for 11 consecutive days before exposing female rats to 6 Gy gamma irradiation and continued to receive soybean isoflavones until sacrificed 10 and 15 days post irradiation . Irradiation induced significant decrease in white blood cells(WBCs), red blood cells (RBCs), haemoglobin (HB), haematocrit (Ht %), glutathione (GSH), calcium (CA) and estradiol, while it induced significant elevation in serum malondialdehyde(MDA), inorganic phosphorus, thyroxine 3 (T 3 ) and thyroxine 4 (T 4 ), 10 and 15 days post -irradiation . diadzein and genistein treatment before and through irradiation accelerated the recovery of circulating WBCs and RBCs, elevated HB, Hct % GSH meanwhile hindered the depression in CA. Soy isoflavones depressed MDA and ameliorated the increase in T 3 , T 4 and elevated estradiol and phosphorus levels 10 and 15 days post irradiation. the results recommend combined treatment with genistein and daidzein to mitigate irradiation-induced damage and bon loss and suggest clinical application of these isoflavones in radiotherapy

Irradiation of amorphous metallic alloys: defect production and local order evolution

International Nuclear Information System (INIS)

Hillairet, J.; Balanzat, E.; Audouard, A.; Jousset, J.C.

1983-06-01

This paper deals with the problem of the nature and dynamic characteristics of the ''defects'' which are produced in metallic glasses as a result of irradiation with fast particles. It discusses also the modifications in the state of local order and other structural changes brought by the creation and migration of these defects [fr

Contribution of caspase-3 differs by p53 status in apoptosis induced by X-irradiation

International Nuclear Information System (INIS)

Kobayashi, Daisuke; Tokino, Takashi; Watanabe, Naoki

2001-01-01

We investigated the effect of p53 status on involvement of caspase-3 activation in cell death induced by X-irradiation, using rat embryonic fibroblasts (REFs) transduced with a temperature-sensitive mutant (mt) p53 gene. Cells with wild-type (wt) p53 showed greater resistance to X-irradiation than cells with mt p53. In cells with wt p53, X-irradiation-induced apoptosis was not inhibited by the caspase-3 inhibitor acetyl-L-aspartyl-L-methionyl-L-glutaminyl-L-aspartyl-aldehyde (Ac-DMQD-CHO) and caspase-3 activity was not elevated following X-irradiation, although induction of p53 and p21/WAF-1 protein was observed. In contrast, irradiated cells with mt p53 showed 89% inhibition of cell death with Ac-DMQD-CHO and 98% inhibition with the antioxidant N-acetyl-L-cysteine (NAC). In cells with mt p53, caspase-3 activity was increased approximately 5 times beyond baseline activity at 24 h after irradiation. This increase was almost completely inhibited by NAC. However, inhibition of caspase-3 by Ac-DMQD-CHO failed to decrease production of reactive oxygen species by cells with mt p53. Differential involvement of caspase-3 is a reason for differences in sensitivity to X-irradiation in cells with different p53 status. Caspase-3 activation appears to occur downstream from generation of reactive oxygen species occurring independently of wt p53 during X-irradiation-induced cell death. (author)

Pre-irradiation induced emulsion graft polymerization of acrylonitrile onto polyethylene nonwoven fabric

International Nuclear Information System (INIS)

Liu Hanzhou; Yu Ming; Deng Bo; Li Linfan; Jiang Haiqing; Li Jingye

2012-01-01

Acrylonitrile has been widely used in the modification of polymers by graft polymerization. In the present work, pre-irradiation induced emulsion graft polymerization method is used to introduce acrylonitrile onto PE nonwoven fabric instead of the traditional reaction in organic solvents system. The degree of grafting (DG) is measured by gravimetric method and the kinetics of the graft polymerization is studied. The existence of the graft chains is proven by Fourier transform infrared spectroscopy (FT-IR) analysis. Thermal stability of the grafted polymer is measured by Thermogravimetric analysis (TGA). - Highlights: → Acrylonitrile is grafted onto pre-irradiated polyethylene (PE) nonwoven fabrics. → Emulsion system is applied, for the graft polymerization avoids organic solvent. → Kinetic of the pre-irradiation induced graft polymerization is studied. → Optimal condition is determined at the temperature below the b.p. of acrylonitrile.

Light ion irradiation for unfavorable soft tissue sarcoma

International Nuclear Information System (INIS)

Linstadt, D.; Castro, J.R.; Phillips, T.L.; Petti, P.L.; Collier, J.M.; Daftari, I.; Schoethaler, R.; Rayner, A.

1990-09-01

Between 1978 and 1989, 32 patients with unfavorable soft tissue sarcoma underwent light ion (helium, neon) irradiation with curative intent at Lawrence Berkeley Laboratory. The tumors were located in the trunk in 22 patients and head and neck in 10. Macroscopic tumor was present in 22 at the time of irradiation. Two patients had tumors apparently induced by previous therapeutic irradiation. Follow-up times for surviving patients ranged from 4 to 121 months (median 27 months). The overall 3-year actuarial local control rate was 62%; the corresponding survival rate was 50%. The 3-year actuarial control rate for patients irradiated with macroscopic tumors was 48%, while none of the patients with microscopic disease developed local recurrence (100%). The corresponding 3-year actuarial survival rates were 40% (macroscopic) and 78% (microscopic). Patients with retroperitoneal sarcoma did notably well; the local control rate and survival rate were 64% and 62%, respectively. Complications were acceptable; there were no radiation related deaths, while two patients (6%) required operations to correct significant radiation-related injuries. These results appear promising compared to those achieved by low -LET irradiation, and suggest that this technique merits further investigation

Correlation between locally deformed structure and oxide film properties in austenitic stainless steel irradiated with neutrons

Energy Technology Data Exchange (ETDEWEB)

Chimi, Yasuhiro, E-mail: chimi.yasuhiro@jaea.go.jp [Japan Atomic Energy Agency (JAEA), 2-4 Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan); Kitsunai, Yuji [Nippon Nuclear Fuel Development, 2163 Narita-cho, Oarai-machi, Higashi-ibaraki-gun, Ibaraki 311-1313 (Japan); Kasahara, Shigeki [Japan Atomic Energy Agency (JAEA), 2-4 Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan); Chatani, Kazuhiro; Koshiishi, Masato [Nippon Nuclear Fuel Development, 2163 Narita-cho, Oarai-machi, Higashi-ibaraki-gun, Ibaraki 311-1313 (Japan); Nishiyama, Yutaka [Japan Atomic Energy Agency (JAEA), 2-4 Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan)

2016-07-15

To elucidate the mechanism of irradiation-assisted stress corrosion cracking (IASCC) in high-temperature water for neutron-irradiated austenitic stainless steels (SSs), the locally deformed structures, the oxide films formed on the deformed areas, and their correlation were investigated. Tensile specimens made of irradiated 316L SSs were strained 0.1%–2% at room temperature or at 563 K, and the surface structures and crystal misorientation among grains were evaluated. The strained specimens were immersed in high-temperature water, and the microstructures of the oxide films on the locally deformed areas were observed. The appearance of visible step structures on the specimens' surface depended on the neutron dose and the applied strain. The surface oxides were observed to be prone to increase in thickness around grain boundaries (GBs) with increasing neutron dose and increasing local strain at the GBs. No penetrative oxidation was observed along GBs or along surface steps. - Highlights: • Visible step structures depend on the neutron dose and the applied strain. • Local strain at grain boundaries was accumulated with the neutron dose. • Oxide thickness increases with neutron dose and local strain at grain boundaries. • No penetrative oxidation was observed along grain boundaries or surface steps.

The role of strain localization in the fracture of irradiated pressure tube material

International Nuclear Information System (INIS)

Dutton, R.

1989-04-01

This report reviews those phenomena that lead to strain localization in zirconium alloys, with particular reference to the role played by the formation of shear bands in fracture processes. The important influence of plastic deformation, in general, on fracture mechanisms is emphasized. This is to be expected when elastic-plastic fracture mechanics is the chosen analytical technique. Intensely inhomogeneous characteristics of strain localization cause an abrupt bifurcation in the evolution of deformation strain and lead to plastic instability linked with intrinsic material behaviour (e.g., work softening) or of geometric origin (e.g., localized necking). Both of these effects are discussed in relation to measurable deformation parameters, such as the work hardening rate and strain rate sensitivity, which determine the degree of resistance to plastic instability. The modifying effect of irradiation on these quantities is given specific attention, the appropriate literature pertaining to Zircaloy and Zr-2.5% Nb being reviewed. Recommendations are made for a combined experimental and theoretical program to characterize strain localization and reduced ductility in irradiated cold-worked Zr-2.5% Nb pressure tube material. The relationship between the deformation properties and the fracture behaviour is discussed

Effect of irradiation-induced defects on fusion reactor ceramics

International Nuclear Information System (INIS)

Clinard, F.W. Jr.

1986-01-01

Structural, thermal, and electrical properties critical to performance of ceramics in a fusion environment can be profoundly altered by irradiation effects. Neutron damage may cause swelling, reduction of thermal conductivity, increase in dielectric loss, and either reduction or enhancement of strength depending on the crystal structure and defect content of the material. Absorption of ionizing energy inevitably leads to degradation of insulating properties, but these changes can be reduced by alterations in structural or compositional makeup. Assessment of the irradiation response of candidate ceramics Al 2 O 3 , MgAl 2 O 4 , SiC and Si 3 N 4 shows that each may find use in advanced fusion devices. The present understanding of irradiation-induced defects in ceramics, while far from complete, nevertheless points the way to methods for developing improved materials for fusion applications

Five cases of squamous cell carcinoma induced by irradiation

International Nuclear Information System (INIS)

Omoto, Kayo; Tani, Tasaburo; Nagata, Hiroyuki; Kohda, Mamoru; Ueki, Hiroaki

1985-01-01

Five cases of squamous cell carcinoma (skin) induced by irradiation are reported. Three cases had been given radiotherapy for benign skin disorders, tinea pedis, lichen Vidal, and dermatitis papillaris capillitis. The other two cases were medical doctors who had developed carcinoma as the result of advanced radiodermatitis. (author)

Electronic excitation induced modifications in elongated iron nanoparticle encapsulated multiwalled carbon nanotubes under ion irradiation

Science.gov (United States)

Saikiran, V.; Bazylewski, P.; Sameera, I.; Bhatia, Ravi; Pathak, A. P.; Prasad, V.; Chang, G. S.

2018-05-01

Multi-wall carbon nanotubes (MWCNT) filled with Fe nanorods were shown to have contracted and deformed under heavy ion irradiation. In this study, 120 MeV Ag and 80 MeV Ni ion irradiation was performed to study the deformation and defects induced in iron filled MWCNT under heavy ion irradiation. The structural modifications induced due to electronic excitation by ion irradiation were investigated employing high-resolution transmission electron microscopy, micro-Raman scattering experiments, and synchrotron-based X-ray absorption and emission spectroscopy. We understand that the ion irradiation causes modifications in the Fe nanorods which result in compressions and expansions of the nanotubes, and in turn leads to the buckling of MWCNT. The G band of the Raman spectra shifts slightly towards higher wavenumber and the shoulder G‧ band enhances with the increase of ion irradiation fluence, where the buckling wavelength depends on the radius 'r' of the nanotubes as exp[(r)0.5]. The intensity ratio of the D to G Raman modes initially decreases at the lowest fluence, and then it increases with the increase in ion fluence. The electron diffraction pattern and the high resolution images clearly show the presence of ion induced defects on the walls of the tube and encapsulated iron nanorods.

Inhomogeneous strain induced by fast neutron irradiation in NaKSO4 crystals

International Nuclear Information System (INIS)

Kandil, S.H.; El Gamal, M.A.; El Khatib, A.; El Wahidy, E.F.

1987-06-01

The effect of fast neutron irradiation on the thermal properties of NaKSO 4 crystals was studied around the phase transition temperature T c =453 K. The thermal expansion coefficient as well as the phase transition temperature were found to be dependent upon the irradiation dose. The specific heat, C p , showed multiple peaks in the phase transition temperature region. An explanation of this behaviour was based on the induced inhomogeneous strain in the crystal casued by the neutron irradiation process. (author). 10 refs, 3 figs

Local Anesthetic-Induced Neurotoxicity

NARCIS (Netherlands)

Verlinde, Mark; Hollmann, Markus W.; Stevens, Markus F.; Hermanns, Henning; Werdehausen, Robert; Lirk, Philipp

2016-01-01

This review summarizes current knowledge concerning incidence, risk factors, and mechanisms of perioperative nerve injury, with focus on local anesthetic-induced neurotoxicity. Perioperative nerve injury is a complex phenomenon and can be caused by a number of clinical factors. Anesthetic risk

Histopathologic changes induced in rats by localized x-irradiation of an exteriorized segment of the small intestine

Energy Technology Data Exchange (ETDEWEB)

Sebes, J I; Zaldivar, R; Vogel, Jr, H H [Tennessee Univ., Memphis (USA). Dept. of Radiation Oncology; Tennessee Univ., Memphis (USA). Dept. of Diagnostic Radiology)

1975-10-01

The sequence of histopathological changes was described after X-irradiation of the exteriorized segment (3 cm) of the rat ileum with a single dose of 2,200 R. A one-year follow-up was provided in rats whose exteriorized intestinal segments were irradiated. Comparisons were made between one group of animals in which the superior mesenteric artery and vein were clamped during irradiation and a second group in which these vessels were not clamped. A third group of sham-irradiated controls was used for comparisons. There was a delay in the onset and progression of the radiation damage to the mucosa of the hypoxic animals in the acute post-irradiation phase. In addition, prolongation of survival in the rats with the superior mesenteric vessels clamped was observed. Mucosal regeneration was noted, occurring at 52 days post-exposure. No adenocarcinomas were found up to 354 days after irradiation. An angiofibroma and a highly differentiated osteoid lesion were described.

Study of irradiation induced defects and phase instability in β phase of Zr Excel alloy with in-situ heavy ion irradiation

International Nuclear Information System (INIS)

Yu, H.; Yao, Z.; Kirk, M.A.; Daymond, M.R.

2015-01-01

In situ heavy ion irradiation with 1 MeV Kr"2"+ was carried out to study irradiation induced phase change and atomic lattice defects in theβ phase of Zr Excel alloy. No decomposition of β-Zr was observed under irradiation at either 200 "oC or 450 "oC. However, ω-Zr particles experienced shape change and shrinkage associated enrichment of Fe in the β/ω interface at 200 "oC irradiation but not at 450 "oC. The defect evolution in the β-phase was examined with single phase Zr-20Nb alloy. It was found that dislocation loops with Burgers vector 1/2 and both present in β-Zr under room temperature irradiation. (author)

Changes in intestinal intraepithelial lymphocytes due to local irradiation of a portion of the maxilla in mice

Energy Technology Data Exchange (ETDEWEB)

Satoh, Daigo; Tamazawa, Ken; Yosue, Takashi; Sakai, Yasuo; Suzuki, Masayuki [Nihon Univ., Tokyo (Japan). School of Dentistry; Arai, Chiaki; Inagaki, Hiroyuki

2000-05-01

We have been investigating the changes of lymphocyte subsets in the immune organs after head and neck irradiation. The present study investigated the influence due to local irradiation (10 Gy) of a portion of the maxilla on intestinal intraepithelial lymphocytes (i-IEL) in mice. We analyzed the percentage of subpopulations in i-IEL following irradiation using two-color fluorometry (anti-TCR{alpha}{beta}, TCR{gamma}{delta}, CD4 and CD8 monoclonal antibodies), and the outcome was compared with that obtained from non-irradiation groups. The result was that the percentage of {alpha}{beta}T cells, {gamma}{delta}T cells, CD4{sup +}SPT cells and CD8{sup +}SPT cells did not show any significant change and the fact differed from that in spleen and thymus where the percentage of these subpopulations was significantly changed. Although spleen and thymus reflect damaged lymphocytes that had circulated through the irradiation field, the result indicates that the balance among i-IEL subsets does not change after irradiation. The reason that equilibrium of i-IEL subsets remains stable seems related to localization of the small intestine and radioresistance. It was also indicated that the effect on the oral epithelium in the irradiation field reflects the percentages of i-IEL subsets. (author)

Localization of specific sequences and DNA single-strand breaks in individual UV-A-irradiated human lymphocytes by COMET FISH

Science.gov (United States)

Bock, Claudia; Rapp, Alexander; Dittmar, Heike; Monajembashi, Shamci; Greulich, Karl-Otto

1999-01-01

The COMET assay, a single cell electrophoresis technique which allows to separate electrophoretically fractionated DNA according to size has been combined with fluorescence in situ hybridization (FISH) which allows to localize specific genes or gene regions. This combination (COMET FISH) allows the detection of DNA single strand breaks in specific regions of the genome of human lymphocytes at the single cell level. Various types of DNA probes, e.g. centromere-, (alpha) - satellite-, telomere-, whole chromosome-, single copy- and region specific DNA probes have been used to investigate whether the UV-A induced DNA single strand breaks are distributed randomly all over the human genome or induced at specific sites ('hot spots'). In the investigated human peripheral blood lymphocytes all but one centromere reveal low sensitivity for UV-A irradiation (500 kJ/m2), while telomeres are randomly distributed over COMET heads and tails. The human chromosome 1 is fractionated by irradiation, but remains in the COMET head, indicating an only moderate degree of fractionation. Among three tested single copy probes, c- myc, p53 and p58, the p53 gene located on chromosome 17p13.1 and the p58 gene (1p36) appear to be located in UV-A stable regions of the human genome in 95% of 65 investigated lymphocytes. In contrast, the c-myc proto-oncogene (8q24) is found in the COMET tail in 90% of the 27 investigated lymphocytes and thus appears to be more sensitive to UV-A irradiation.

Failure of irradiated beef and ham to induce genetic aberrations of Drosophila

International Nuclear Information System (INIS)

Mittler, S.

1979-01-01

Ham that had been irradiated by electrons and beef which had been exposed to gamma rays from 60 Co were fed to Drosophila melanogaster to determine whether meat sterilized by these methods would induce genetic aberrations. The results showed that for yB/sc 8 y + Y males, fed on irradiated ham or beef, thermally preserved beef or frozen beef for their entire larval life, there was no significant increase in the loss of X or Y chromosomes or non-disjunction of these chromosomes; there was also no significant increase in any of the broods. Similarly for the Oregon R males, there was no significant increase in yield of sex-linked recessive lethals. Thus feeding of irradiated ham and beef to Drosophila males did not induce significant increases in genetic aberrations. The present findings are discussed in relation to the conflicting results of previous studies. (U.K.)

Ag induced suppression of irradiation response in YBCO/Ag composite thin films

International Nuclear Information System (INIS)

Behera, D.; Mohanty, T.; Mohanta, D.; Patnaik, K.; Mishra, N.C.; Senapati, L.; Kanjilal, D.; Mehta, G.K.; Pinto, R.

1999-01-01

Practical application of cuprate superconductors in radiation environment demands that these systems remain insensitive to the irradiation induced defects. The cuprate superconductors however are many orders of magnitude more sensitive than the conventional low T c superconductors. To suppress the irradiation sensitivity of cuprates we consider a crystal engineering approach where metal ions as Ag is made to occupy inter and intra-granular sites of YBa 2 Cu 3 O 7 thin films. We show that superconducting and normal state properties of YBCO/Ag composite thin films prepared by laser ablation remain unchanged under 140 MeV Si ion irradiation up to fluence of 8 x 10 14 ions/cm 2 . The inter- and intra-granular occupancy of Ag is shown to induce microstructural modifications and rigidity to the CuO chains respectively which in turn lead to the radiation insensitivity of the composite films. (author)

Incidence and nature of tumors induced in Sprague-Dawley rats by gamma-irradiation

International Nuclear Information System (INIS)

Gross, L.; Dreyfuss, Y.; Faraggiana, T.

1988-01-01

In our previous studies carried out on inbred rats of the Sprague-Dawley strain, the tumor incidence was increased following irradiation (150 rads, 5 times, at weekly intervals), from 22 to 93% in females and from 5 to 59% in males. Experiments here reported suggest that 2 consecutive total-body gamma-irradiations of 150 rads each are sufficient to induce in rats the development of tumors, some malignant; 18 of 19 females (94.7%) developed tumors at an average age of 11.4 mo, and seven of the 14 males in this group (50%) developed tumors at an average age of 10.4 mo. In the second group, which received 3 consecutive gamma-irradiations, 20 of 23 females (86.9%) and 5 of 13 males (38.4%) developed tumors at average ages of 9.1 and 7.5 mo, respectively. In the third group, among rats which received 4 consecutive gamma-irradiations, 17 of 19 females (89.4%) and 4 of 12 males (33.3%) developed tumors at average ages of 9.4 and 10.5 mo, respectively. The etiology of tumors either developing spontaneously or induced by irradiation in rats remains to be clarified. Our attempts to detect virus particles by electron microscopy in such tumors or lymphomas have not been successful. As a working hypothesis, we are tempted to theorize that tumors or lymphomas developing spontaneously or induced by gamma irradiation in rats are caused by latent viral agents which are integrated into the cell genome and are cell associated, i.e., not separable from the rat tumor cells by conventional methods thus far used

N-Acetyl-L-cysteine protects thyroid cells against DNA damage induced by external and internal irradiation.

Science.gov (United States)

Kurashige, Tomomi; Shimamura, Mika; Nagayama, Yuji

2017-11-01

We evaluated the effect of the antioxidant N-acetyl-L-cysteine (NAC) on the levels of reactive oxygen species (ROS), DNA double strand breaks (DSB) and micronuclei (MN) induced by internal and external irradiation using a rat thyroid cell line PCCL3. In internal irradiation experiments, ROS and DSB levels increased immediately after 131 I addition and then gradually declined, resulting in very high levels of MN at 24 and 48 h. NAC administration both pre- and also post- 131 I addition suppressed ROS, DSB and MN. In external irradiation experiments with a low dose (0.5 Gy), ROS and DSB increased shortly and could be prevented by NAC administration pre-, but not post-irradiation. In contrast, external irradiation with a high dose (5 Gy) increased ROS and DSB in a bimodal way: ROS and DSB levels increased immediately after irradiation, quickly returned to the basal levels and gradually rose again after >24 h. The second phase was in parallel with an increase in 4-hydroxy-2-nonenal. The number of MN induced by the second wave of ROS/DSB elevations was much higher than that by the first peak. In this situation, NAC administered pre- and post-irradiation comparably suppressed MN induced by a delayed ROS elevation. In conclusion, a prolonged ROS increase during internal irradiation and a delayed ROS increase after external irradiation with a high dose caused serious DNA damage, which were efficiently prevented by NAC. Thus, NAC administration even both after internal or external irradiation prevents ROS increase and eventual DNA damage.

Improvement of local varieties of rice (Oryza glaberrima) for resistance to shattering and grain quality by induced mutations

Energy Technology Data Exchange (ETDEWEB)

Cisse, F; Dione, M; Kelly, S [Institute d` Economie Rurale, Station de Recherche Agronomique, Mopti (Mali)

1997-12-01

In Mali, a large area of rice is planted with the local rice, O. glaberrima which under conditions of low rainfall and flood water is more hardy to stress than the introduced O. sativa cultivars. A program to improve the local varieties of O. glaberrima by induced mutations was started in 1988. Ten local varieties were irradiated with 20 and 30 krad. In M{sub 4} of cv. `Gorbal`, irradiated with 20 krads, 13 variants were selected. Five of these were evaluated in M{sub 5} for their agronomic performance. The induced mutants in the remaining 9 varieties were highly sterile with 90% or more sterility in the M{sub 2} and M{sub 3}. Irradiation with 20-30 krad gave high survival (70-95%), and several mutants with white kernel were obtained from the red seeded types. Nearly two-third of the identified mutants had white caryopsis. There is better consumer acceptance of the white seeded type of rice than the red seeded varieties in Mali and the white seeded mutants may have an added premium in the market. The field performance of the M{sub 5} mutants was investigated. Preliminary results showed that some of mutants derived from cv. `Gorbal` were early in maturity and had more panicles per plant, but had a lower 1000-kernel weight, and did not differ from the parent in grain yield. Additional trials are planned to establish potential of the mutants for yield and quality. Three more cultivars of O. glaberrima - `Haira`, `Tombo` and `Yele` - were irradiated with 20 and 60 krads, and gave 75, 81 and 72% seed viability, respectively. M{sub 1} showed reduced plant height. Selection for non-shattering of grains shall be carried out in M{sub 2}. Any plants which are non-shattering but sterile shall be crossed with the parent to recover the mutant types. The taxonomic status of cv. `Gorbal` is not very clear. Isozyme patterns suggest that this cultivar may belong to O. sativa and not to O. glaberrima. To establish its taxonomic status, crosses shall be made with O. sativa and O

Improvement of local varieties of rice (Oryza glaberrima) for resistance to shattering and grain quality by induced mutations

International Nuclear Information System (INIS)

Cisse, F.; Dione, M.; Kelly, S.

1997-01-01

In Mali, a large area of rice is planted with the local rice, O. glaberrima which under conditions of low rainfall and flood water is more hardy to stress than the introduced O. sativa cultivars. A program to improve the local varieties of O. glaberrima by induced mutations was started in 1988. Ten local varieties were irradiated with 20 and 30 krad. In M 4 of cv. 'Gorbal', irradiated with 20 krads, 13 variants were selected. Five of these were evaluated in M 5 for their agronomic performance. The induced mutants in the remaining 9 varieties were highly sterile with 90% or more sterility in the M 2 and M 3 . Irradiation with 20-30 krad gave high survival (70-95%), and several mutants with white kernel were obtained from the red seeded types. Nearly two-third of the identified mutants had white caryopsis. There is better consumer acceptance of the white seeded type of rice than the red seeded varieties in Mali and the white seeded mutants may have an added premium in the market. The field performance of the M 5 mutants was investigated. Preliminary results showed that some of mutants derived from cv. 'Gorbal' were early in maturity and had more panicles per plant, but had a lower 1000-kernel weight, and did not differ from the parent in grain yield. Additional trials are planned to establish potential of the mutants for yield and quality. Three more cultivars of O. glaberrima - 'Haira', 'Tombo' and 'Yele' - were irradiated with 20 and 60 krads, and gave 75, 81 and 72% seed viability, respectively. M 1 showed reduced plant height. Selection for non-shattering of grains shall be carried out in M 2 . Any plants which are non-shattering but sterile shall be crossed with the parent to recover the mutant types. The taxonomic status of cv. 'Gorbal' is not very clear. Isozyme patterns suggest that this cultivar may belong to O. sativa and not to O. glaberrima. To establish its taxonomic status, crosses shall be made with O. sativa and O. glaberrima. (author). 2 tabs

Effect of irradiation temperature on microstructure of ferritic-martensitic ODS steel

Science.gov (United States)

Klimenkov, M.; Lindau, R.; Jäntsch, U.; Möslang, A.

2017-09-01

The EUROFER-ODS alloy with 0.5% Y2O3 was neutron irradiated with doses up to 16.2 dpa at 250 °C, 350 °C and 450 °C. The radiation induced changes in the microstructure (e.g. dislocation loops and voids) were investigated using transmission electron microscopy (TEM). The number density of radiation induced defects was found to be significantly lower than in EUROFER 97 irradiated at the same conditions. It was found that the appearance and extent of radiation damage strongly depend not only on the irradiation temperature but also on the local number density and size distribution of ODS particles. The higher number density of dislocation loops and voids was found in the local areas with low number density of ODS particles. The interstitial loops with Burgers vector of both ½ and types were detected by imaging using different diffraction conditions.

High-dose radiation-induced meningioma following prophylactic cranial irradiation for acute lymphoblastic leukaemia

International Nuclear Information System (INIS)

Matsuda, Ryosuke; Nikaido, Yuji; Yamada, Tomonori; Mishima, Hideaki; Tamaki, Ryo

2005-01-01

A 12 year-old girl was treated with prophylactic cranial irradiation for acute lymphoblastic leukaemia (ALL). At the age of 39, she was admitted to our hospital for status epilepticus. Computed tomography demonstrated two, enhancing bilateral sided intracranial tumors. After surgery, this patient presented meningiomas which histologically, were of the meningothelial type. The high cure rate in childhood ALL, attributable to aggressive chemotherapy and prophylactic cranial irradiation, is capable of inducing secondary brain tumor. Twelve cases of high-dose radiation-induced meningioma following ALL are also reviewed. (author)

High-dose radiation-induced meningioma following prophylactic cranial irradiation for acute lymphoblastic leukaemia

Energy Technology Data Exchange (ETDEWEB)

Matsuda, Ryosuke; Nikaido, Yuji; Yamada, Tomonori; Mishima, Hideaki; Tamaki, Ryo [National Hospital Organization Osaka Minami Medical Center, Kawachinagano (Japan)

2005-03-01

A 12 year-old girl was treated with prophylactic cranial irradiation for acute lymphoblastic leukaemia (ALL). At the age of 39, she was admitted to our hospital for status epilepticus. Computed tomography demonstrated two, enhancing bilateral sided intracranial tumors. After surgery, this patient presented meningiomas which histologically, were of the meningothelial type. The high cure rate in childhood ALL, attributable to aggressive chemotherapy and prophylactic cranial irradiation, is capable of inducing secondary brain tumor. Twelve cases of high-dose radiation-induced meningioma following ALL are also reviewed. (author)

Irradiation-induced creep in fuel compacts for high-temperature reactor applications

Energy Technology Data Exchange (ETDEWEB)

Veringa, H; Blackstone, R [Stichting Energieonderzoek Centrum Nederland, Petten; Loelgen, R

1977-01-01

Restrained shrinkage experiments at neutron fluences up to 3 x 10/sup 21/ n cm/sup -2/ DNE in the temperature range 600 to 1200/sup 0/C were performed on three different dummy coated-particle fuel compacts in the high-flux reactor at Petten. The data were evaluated to obtain the steady-state radiation creep coefficient of the compacts. It was found that, for the materials investigated, the creep coefficient is temperature dependent, but no clear relationship with Young's modulus could be established. Under certain conditions this irradiation-induced plasticity influences the elastic properties, with the concomitant increase of the creep coefficient. This effect coincides with the formation and further opening up of cracks due to stresses caused by irradiation-induced shrinkage of matrix material.

Irradiation-induced creep in fuel compacts for high-temperature reactor applications

International Nuclear Information System (INIS)

Veringa, H.; Blackstone, R.; Loelgen, R.

1977-01-01

Restrained shrinkage experiments at neutron fluences up to 3 x 10 21 n cm -2 DNE in the temperature range 600 to 1200 0 C were performed on three different dummy coated-particle fuel compacts in the high-flux reactor at Petten. The data were evaluated to obtain the steady-state radiation creep coefficient of the compacts. It was found that, for the materials investigated, the creep coefficient is temperature dependent, but no clear relationship with Young's modulus could be established. Under certain conditions this irradiation-induced plasticity influences the elastic properties, with the concomitant increase of the creep coefficient. This effect coincides with the formation and further opening up of cracks due to stresses caused by irradiation-induced shrinkage of matrix material. (author)

Convoluted dislocation loops induced by helium irradiation in reduced-activation martensitic steel and their impact on mechanical properties

Energy Technology Data Exchange (ETDEWEB)

Luo, Fengfeng [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory, School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Yao, Z. [Department of Mechanical and Materials Engineering, Queen' s University, Kingston, ON, Canada K7L 3N6 (Canada); Guo, Liping, E-mail: guolp@whu.edu.cn [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory, School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Suo, Jinping [State Key Laboratory of Mould Technology, Institute of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Wen, Yongming [Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Hubei Nuclear Solid Physics Key Laboratory, School of Physics and Technology, Wuhan University, Wuhan 430072 (China)

2014-06-01

Helium irradiation induced dislocation loops in reduced-activation martensitic steels were investigated using transmission electron microscopy. The specimens were irradiated with 100 keV helium ions to 0.8 dpa at 350 °C. Unexpectedly, very large dislocation loops were found, significantly larger than that induced by other types of irradiations under the same dose. Moreover, the large loops were convoluted and formed interesting flower-like shape. The large loops were determined as interstitial type. Loops with the Burgers vectors of b=〈100〉 were only observed. Furthermore, irradiation induced hardening caused by these large loops was observed using the nano-indentation technique.

Irradiation-induced precipitation and solute segregation in alloys. Fourth annual progress report, February 1, 1981-March 31, 1982

International Nuclear Information System (INIS)

Ardell, A.J.

1982-04-01

The studies of irradiation-induced solute segregation (IISS) and irradiation-induced precipitation (IIP) in Ni-Si and Pd-Fe alloys have been completed. Progress is reported for several other projects: irradiation damage in binary Pd-Cr, -Mn and -V alloys (15 at. %); IIP in Pd-Mo and Pd-W alloys; IIP in Pd-25 at. % Cr alloy; and irradiation damage effects in proton-bombarded metallic glasses (Ni-65 Zr, 40 Fe 40 Ni 14 P6B). 27 figures

Radiation-induced cancer of the esophagus after postoperative irradiation for breast cancer

International Nuclear Information System (INIS)

Ito, Ichiro; Miyaishi, Kazuo; Mitsuhashi, Norio; Ito, Jun; Inoue, Tomio

1978-01-01

Two cases of radiation-induced cancer of the esophagus after postoperative irradiation for breast cancer were reported. Latent period of case 1 (cervical esophagus) was 12 years, and case 2 (middle thoracic esophagus) was 16 years. Radiographically the lesions were both serrated, and histologically, case 1 was ''poorly differentiated'' and case 2 was ''moderately differentiated'' squamous cell carcinoma. Histological types of basic breast cancer were both papillotubular carcinomas. Previous irradiation doses were 4180 rads for case 1 and 1860 rads for case 2. The esophageal cancers were remarkably improved by radiation therapy. It should be emphasized that radiation therapy is useful for the radiation-induced cancer of the esophagus. (author)

Irradiation-induced hardening/softening in SiO2 studied with instrumented indentation

International Nuclear Information System (INIS)

Nakano, Shinsuke; Muto, Shunsuke; Tanabe, Tetsuo

2005-01-01

To understand the plastic deformation mechanism of SiO 2 polytypes, we measured the mechanical parameters of He + -irradiated crystalline SiO 2 (α-quartz, c-SiO 2 ) and vitreous SiO 2 (silica glass, v-SiO 2 ) as functions of the irradiation dose, by using the instrumented indentation method combined with a finite-element analysis. We extracted the effects of local rotation and bending of the SiO 4 framework (the degree of local structural freedom), which play key roles in the plastic deformation, and expressed the hardness change with a simple formula. For v-SiO 2 , the changes in the density and the number of broken bonds correlated well with the change in the degree of freedom. In contrast, for c-SiO 2 the present formulation was insufficient to fully express the hardness change in the structural disordering regime. The structure change by irradiation peculiar to this material is discussed, based on the theoretical formulation

The Potential Therapeutic Effect of Curcumin on the Adjuvant-induced Arthritis in Irradiated Rats

International Nuclear Information System (INIS)

El-Ghazaly, M.A.; Nada, A.S.; Hegazy, M.E.; Kenawy, S.A.

2010-01-01

Naturalistic that provide medical or health benefits, including prevention and treatment of diseases. They may be advantageous in inflammation and exposure to radiation. The study was conducted to investigate curcumin potential to modulate, counteract or prevent the inflammatory response induced in arthritic irradiated and non-irradiated rats using the adjuvant-induced arthritis model. Diclofenac was used as a reference standard non-steroidal anti-inflammatory drug (NSAID). Results indicated that exposure of rats to single dose of gamma-radiation (6 Gy) before induction of inflammation increased production of prostaglandin E2 (PGE2), tumour necrosis factor-gamma (TNF-gamma) and malondialdehyde (MDA) levels in serum. Blood glutathione (GSH) was shown to be reduced in irradiated animals. Curcumin suppressed the elevated levels of TNF-gamma, PGE2 and MDA and was able to restore blood GSH level. Reduction in liver contents of copper (Cu), zinc (Zn), selenium (Se) and iron (Fe) was recorded in animals irradiated before induction of inflammation. In addition, curcumin restored the hepatic contents of these trace elements. The present results suggest that irradiation of rats caused marked changes in the inflammatory response, while curcumin suppressed the inflammatory response in both irradiated and normal rats

Preliminary study of the irradiation-induced modification of skin permeability

International Nuclear Information System (INIS)

Coelho, R.; Istin, M.

1978-01-01

Irradiation of the skin of an animal leads immediately to a strong increase in vascular permeability. If a dye is at once injected intraveinously it diffuses very rapidly in the irradiated zone, this becomes highly coloured and the colour intensity measurement gives a clue to the severity of the lesions produced. This phenomenon has been used in the past as a pharmacological test to study vascular permeability and is employed in this work to observe the effect of diosmine-titrated flavonoids on vascular permeability in inflammatory diseases. The capillary permeability increase due to local γ irradiation of rabbit skin has been accurately determined by measurement of the colouration observed after injection of Geigy Blue. Diosmine, injected intraperitoneally, protects the vascular system against increased permeability due to ionising radiations [fr

Low temperature irradiation effects on iron-boron based amorphous metallic alloys

International Nuclear Information System (INIS)

Audouard, Alain.

1983-01-01

Three iron-boron amorphous alloys and the crystalline Fe 3 B alloy have been irradiated at liquid hydrogen temperature. 2,4 MeV electron irradiation induces the creation of point defects in the amorphous alloys as well as in the crystalline Fe 3 B alloy. These point defects can be assimilated to iron ''Frenkel pairs''. They have been characterized by determining their intrinsic electrical resistivity and their formation volume. The displacement threshold energy of iron atoms has also been determined. 10 B fission fragments induce, in these amorphous alloys, displacement cascades which lead to stable vacancy rich zones. This irradiation also leads to a structural disorder in relation with the presence of defects. 235 U fission fragments irradiation modifies drastically the structure of the amorphous alloys. The results have been interpreted on the basis of the coexistence of two opposite processes which induce local disorder and crystallisation respectively [fr

Study of irradiation induced defects and phase instability in β phase of Zr Excel alloy with in-situ heavy ion irradiation

Energy Technology Data Exchange (ETDEWEB)

Yu, H.; Yao, Z., E-mail: 12hy1@queensu.ca [Queen' s University, Department of Mechanical and Materials Engineering, Kingston, ON (Canada); Kirk, M.A. [Argonne National Laboratory, Materials Science Division, Argonne, IL (United States); Daymond, M.R. [Queen' s University, Department of Mechanical and Materials Engineering, Kingston, ON (Canada)

2015-07-01

In situ heavy ion irradiation with 1 MeV Kr{sup 2+} was carried out to study irradiation induced phase change and atomic lattice defects in theβ phase of Zr Excel alloy. No decomposition of β-Zr was observed under irradiation at either 200 {sup o}C or 450 {sup o}C. However, ω-Zr particles experienced shape change and shrinkage associated enrichment of Fe in the β/ω interface at 200 {sup o}C irradiation but not at 450 {sup o}C. The defect evolution in the β-phase was examined with single phase Zr-20Nb alloy. It was found that dislocation loops with Burgers vector 1/2<111> and <001> both present in β-Zr under room temperature irradiation. (author)

Partial characterization of bacteriocin induced by irradiated and non-irradiated strain of yersinia enterocolitical

International Nuclear Information System (INIS)

Awny, N.M.

1991-01-01

Twenty isolates of yersinia enterocolitica were tested for the inhibition of the growth of different strains of yersinia. The screening tests revealed three possible bacteriocinogenic strains. One of them was selected for additional studies after it was shown that its inhibitory substances differed in their activity spectra. The gamma irradiated strain lost the ability to produce bacteriocin at 0.6 kGy level. Crude preparation of bacteriocin obtained from the wild strain were not affected by chloroform or other organic solvents but inactivated by trypsin and heating at 80 C for 45 min. Bacteriocin induced by irradiated strain was easily inactivated by thermal treatment. Exposure of agar fragments containing the inhibitory active component to a pH value ranging between 2 to 11 did not affect bactericidal activity.4 tab

Effectiveness of trimethylopropane trimethacrylate for the electron-beam-irradiation-induced cross-linking of polylactic acid

Energy Technology Data Exchange (ETDEWEB)

Ng, Hon-Meng [Department of Chemical Engineering, Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Genting Kelang, 53300 Setapak, Kuala Lumpur (Malaysia); Bee, Soo-Tueen, E-mail: beest@utar.edu.my [Department of Chemical Engineering, Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Genting Kelang, 53300 Setapak, Kuala Lumpur (Malaysia); Ratnam, C.T. [Radiation Processing Technology Division, Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia); Sin, Lee Tin; Phang, Yee-Yao; Tee, Tiam-Ting [Department of Chemical Engineering, Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Genting Kelang, 53300 Setapak, Kuala Lumpur (Malaysia); Rahmat, A.R. [Department of Polymer Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor (Malaysia)

2014-01-15

Highlights: • Investigation of trimethylopropane trimethacrylate (TMPTMA) on electron beam irradiated PLA. • Irradiated PLA blends were weakened by incorporation of high amount of TMPTMA. • TMPTMA interacts with polymer free radicals to build crosslinking network. -- Abstract: The purpose of this research was to investigate the effects of various loading levels of trimethylopropane trimethacrylate (TMPTMA) on the properties of polylactic acid (PLA) cross-linked via electron-beam irradiation. PLA was compounded with 3–5 wt.% of TMPTMA to induce cross-linking upon subjection to electron-beam irradiation doses of 25–250 kGy. The physical properties of the PLA samples were characterised by means of X-ray diffraction, gel fraction and scanning electron microscopy analyses on fractured surfaces after tensile tests. The presence of TMPTMA in PLA was found to effectively increase the crystallite size and gel fraction. However, higher loading levels of TMPTMA could compromise the properties of the PLA/TMPTMA samples, indicating that a larger amount of monomer free radicals might promote degradation within the substantially cross-linked amorphous phase. Irradiation-induced cross-linking in the samples could improve the cross-linking density while decreasing the elongation and interfering with the crystallisation. These effects are caused by the intensive irradiation-induced chain scission that is responsible for the deterioration of the mechanical and crystalline properties of the samples.

The protective effect of Sambucus ebulus against lung toxicity induced by gamma irradiation in mice

Directory of Open Access Journals (Sweden)

Mohammad Karami

2015-01-01

Full Text Available The aim of present study was to investigate the potential antioxidant and lung protective activities of Sambucus ebulus (SE against toxicity induced by gamma irradiation. Hydroalcoholic extract of SE (20, 50 and 100 mg/kg was studied for its lung protective activity. Phenol and flavonoid contents of SE were determined. Male C57 mice were divided into ten groups with five mice per group. Only the first and second groups (as negative control received intraperitoneally normal saline fluid. Groups 3 to 5 received only SE extract at doses of 20 mg/kg, 50 mg/kg and 100 mg/kg intraperitoneally; three groups were repeatedly injected for 15 days as chronic group. Groups 6 to 8 received a single-dose of gamma irradiation just 2 hours before irradiation as acute group. The ninth and tenth groups (as positive control received only gamma rays. Animal was exposed whole-body to 6 Gy gamma radiation. After irradiation, tissue sections of lung parenchyma were examined by light microscope for any histopathologic changes. SE at doses 50 and 100 mg/kg improved markedly histopathological changes induced by gamma irradiation in lung. Lung protective effect of SE could be due to attention of lipid peroxidation. Our study demonstrated that SE as a natural product has a protective effect against lung toxicity induced by   gamma irradiation in animal.

Effectiveness of trimethylopropane trimethacrylate for the electron-beam-irradiation-induced cross-linking of polylactic acid

International Nuclear Information System (INIS)

Ng, Hon-Meng; Bee, Soo-Tueen; Ratnam, C.T.; Sin, Lee Tin; Phang, Yee-Yao; Tee, Tiam-Ting; Rahmat, A.R.

2014-01-01

Highlights: • Investigation of trimethylopropane trimethacrylate (TMPTMA) on electron beam irradiated PLA. • Irradiated PLA blends were weakened by incorporation of high amount of TMPTMA. • TMPTMA interacts with polymer free radicals to build crosslinking network. -- Abstract: The purpose of this research was to investigate the effects of various loading levels of trimethylopropane trimethacrylate (TMPTMA) on the properties of polylactic acid (PLA) cross-linked via electron-beam irradiation. PLA was compounded with 3–5 wt.% of TMPTMA to induce cross-linking upon subjection to electron-beam irradiation doses of 25–250 kGy. The physical properties of the PLA samples were characterised by means of X-ray diffraction, gel fraction and scanning electron microscopy analyses on fractured surfaces after tensile tests. The presence of TMPTMA in PLA was found to effectively increase the crystallite size and gel fraction. However, higher loading levels of TMPTMA could compromise the properties of the PLA/TMPTMA samples, indicating that a larger amount of monomer free radicals might promote degradation within the substantially cross-linked amorphous phase. Irradiation-induced cross-linking in the samples could improve the cross-linking density while decreasing the elongation and interfering with the crystallisation. These effects are caused by the intensive irradiation-induced chain scission that is responsible for the deterioration of the mechanical and crystalline properties of the samples

Viscous surface flow induced on Ti-based bulk metallic glass by heavy ion irradiation

Energy Technology Data Exchange (ETDEWEB)

Zhang, Kun [Key Laboratory of Microgravity (National Microgravity Laboratory), Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190 (China); Hu, Zheng [Key Laboratory of Microgravity (National Microgravity Laboratory), Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190 (China); Science and Technology on Vehicle Transmission Laboratory, China North Vehicle Research Institute, Beijing 100072 (China); Li, Fengjiang [Key Laboratory of Microgravity (National Microgravity Laboratory), Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190 (China); Wei, Bingchen, E-mail: weibc@imech.ac.cn [Key Laboratory of Microgravity (National Microgravity Laboratory), Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190 (China)

2016-12-30

Highlights: • Obvious smoothing and roughening phases on the Ti-based MG surface resulted, which correspond respectively to the normal and off-normal incidence angles. • Atomic force microscopy confirms two types of periodic ripples distributed evenly over the rough surface. • The irradiation-induced viscosity of MG is about 4×10{sup 12} Pa·s, which accords with the theoretical prediction for metallic glasses close to glass transition temperature. • Surface-confined viscous flow plays a dominant quantitative role, which is due to radiation-induced softening of the low-viscosity surface layer. - Abstract: Ti-based bulk metallic glass was irradiated by a 20 MeV Cl{sup 4+} ion beam under liquid-nitrogen cooling, which produced remarkable surface smoothing and roughening that respectively correspond to normal and off-normal incidence angles of irradiation. Atomic force microscopy confirms two types of periodic ripples distributed evenly over the rough glass surface. In terms of mechanism, irradiation-induced viscosity agrees with the theoretical prediction for metallic glasses near glass transition temperature. Here, a model is introduced, based on relaxation of confined viscous flow with a thin liquid-like layer, that explains both surface smoothing and ripple formation. This study demonstrates that bulk metallic glass has high morphological instability and low viscosity under ion irradiation, which assets can pave new paths for metallic glass applications.

Effects of pre-irradiation on isogeneic and semi-isogeneic CFU growth

International Nuclear Information System (INIS)

Buurman, W.A.; Bruggen, I. Van.

1977-01-01

The genetic resistance to a parental bone marrow transplant as demonstrated, when transplantation were performed early after irradiation, failed to occur if the interval between irradiation and transplantation was increased to 4 days. A similar radiation induced weakening of genetic resistance to a parental bone marrow graft in spleen and bone marrow would be demonstrated in mice, which has been irradiated with a sublethal dose at 7 days prior to the lethal irradiation and transplantation. The pre-irradiation of the recipient with a sublethal dose induced an enhancement of the growth in spleen and bone marrow of isogenic transplanted CFU. The pre-irradiation of a single tibia also resulted in a significant weakening of the resistance in the spleen. The experiments with partial body pre-irradiation suggested a local effect of the pre-irradiation, but it could be shown that the enhanced CFU growth is not caused by an enhanced seeding of CFU in pre-irradiation bone marrow. The role of microenvironment in the phenomenon of genetic resistance is discussed. (author)

Meiotic chromosomal translocations in male mice induced by X-irradiation

Energy Technology Data Exchange (ETDEWEB)

Savkovic, N.; Pecevski; Vuksanovic, L.; Radivojevic, D.; Alavantic, D.

1983-01-01

The dose-response curve for reciprocal translocations induced by acute exposure of spermatogonial stem cells to X-rays in treated mice and their F-1 sons was examined. Male mice were totally irradiated with doses of 1Gy;5x1Gy and 5Gy. The obtained results show that frequency of the chromosomal translocations in directly treated animals is dose dependent. The percentage of animals irradiated with 1Gy which had the chromosomal translocations was 60, while this percentage in animals irradiated with single and fractionated dose of 5Gy was 100. The frequency of chromosomal translocations varies from 1.5% to 8.0%. Multivalent configurations in F-1 males were observed after exposure to 5Gy only. The incidence of F-1 translocated males was 17.5%.

Effect of irradiation on the acinar cells of submandibular gland in streptozotocin-induced diabetic rats

International Nuclear Information System (INIS)

Lee, Seung Hyun; Hwang, Eui Hwan; Lee, Sang Rae

2003-01-01

To observe the histologic changes and clusterin expression in the acinar cells of the submandibular gland in streptozotocin-induced diabetic rat following irradiation. Mature Sprague-Dawley rats were divided into three groups: control, diabetic, and diabetic-irradiated groups. Diabetes mellitus was induced in the Sprague-Dawley rats by injecting streptozotocin, while the control rats were injected with citrate buffer only. After 5 days, rats in diabetic-irradiated group were irradiated with single absorbed dose of 10 Gy to the head and neck region. The rats were killed at 1, 3, 7, 14, 21, and 28 days after irradiation. The specimen including the submandibular gland were sectioned and observed using histologic and immunohistochemical methods. Morphologic change of acinar cells was remarkable in the diabetic group, but was not observed in the diabetic-irradiated group. Necrotic tissues were observed in the diabetic-irradiated group. Coloring of toluidine blue stain was most increased at 14 days in the diabetic group, however there were no significant change throughout the period of the experiment in the diabetic-irradiated group. Expression of clusterin was most significant at 14 days in the diabetic group, but gradually decreased with time after 7 days in the diabetic-irradiated group. Degeneration of clusterin was observed in the diabetic-irradiated group. This experiment suggests that the acinar cells of submandibular gland in rats are physiologically apoptosis by the induction of diabetes, but that the apoptosis is inhibited and the acinar cells necrotized after irradiation.

Irradiation induced creep in whiskers of NaCl

International Nuclear Information System (INIS)

Khan, J.A.A.

1977-09-01

Whiskers of NaCl have been grown and irradiated under flexion by X-rays (approximately 2x10 7 R/h) at room temperature and the residual curvature measured. Complete recovery of the initial form of the whisker within an hour's annealing at 400 0 C proves clearly that the observed deformation (creep) is due to the presence of dislocation loops. The choice of NaCl extremely simplifies the experiment and its interpretation since X-rays create point defects one by one. Moreover, this mode of irradiation, at room temperature, produces a very simple situation: perfect interstitial dislocation loops and immobile point defects which are little influenced by the applied stress. The flexion leads to a stress system which hardly differs from an uniaxial stress. One can study separately the preferential nucleation of dislocation loops and their differential growth by carrying out an irradiation under stress followed by an irradiation without stress and vice versa. It is shown that the induced creep is mostly due to the preferential nucleation of dislocation loops and is little affected by the differential growth of these loops. The nucleation period of the loops is very short: a dose of approximately 10 -5 d.p.a. is largely sufficient for the quasi completion of dislocation loops in a crystal having an impurity concentration of approximately 10 -3 [fr

Irradiation induced surface segregation in concentrated alloys: a contribution; Contribution a l`etude de la segregation de surface induite par irradiation dans les alliages concentres

Energy Technology Data Exchange (ETDEWEB)

Grandjean, Y.

1996-12-31

A new computer modelization of irradiation induced surface segregation is presented together with some experimental determinations in binary and ternary alloys. The model we propose handles the alloy thermodynamics and kinetics at the same level of sophistication. Diffusion is described at the atomistic level and proceeds vis the jumps of point defects (vacancies, dumb-bell interstitials): the various jump frequencies depend on the local composition in a manner consistent with the thermodynamics of the alloy. For application to specific alloys, we have chosen the simplest statistical approximation: pair interactions in the Bragg Williams approximation. For a system which exhibits the thermodynamics and kinetics features of Ni-Cu alloys, the model generates the behaviour parameters (flux and temperature) and of alloy composition. Quantitative agreement with the published experimental results (two compositions, three temperatures) is obtained with a single set of parameters. Modelling austenitic steels used in nuclear industry requires taking into account the contribution of dumbbells to mass transport. The effects of this latter contribution are studied on a model of Ni-Fe. Interstitial trapping on dilute impurities is shown to delay or even suppress the irradiation induced segregation. Such an effect is indeed observed in the experiments we report on Fe{sub 50}Ni{sub 50} and Fe{sub 49}Ni{sub 50}Hf{sub 1} alloys. (author). 190 refs.

A Reevaluation of X-Irradiation Induced Phocomelia and Proximodistal Limb Patterning

Science.gov (United States)

Galloway, Jenna L.; Delgado, Irene; Ros, Maria A.; Tabin, Clifford J.

2009-01-01

Phocomelia is a devastating, rare congenital limb malformation in which the long bones are shorter than normal, with the upper portion of the limb being most severely affected. In extreme cases, the hands or fingers are attached directly to the shoulder and the most proximal elements (those closest to the shoulder) are entirely missing. This disorder, previously known in both autosomal recessive and sporadic forms, showed a dramatic increase in incidence in the early 1960’s due to the tragic toxicological effects of the drug thalidomide, which had been prescribed as a mild sedative1, 2. This human birth defect is mimicked in developing chick limb buds exposed to X-irradiation3-5. Both X-irradiation5 and thalidomide-induced phocomelia5, 6 have been interpreted as patterning defects in the context of the Progress Zone Model, which states that a cell’s proximodistal (PD) identity is determined by the length of time spent in a distal limb region termed the “Progress Zone” 7. Indeed, studies of X-irradiation induced phocomelia have served as one of the two major experimental lines of evidence supporting the validity of the Progress Zone Model. Here, using a combination of molecular analysis and lineage tracing, we show that X-irradiation-induced phocomelia is fundamentally not a patterning defect, but rather results from a time-dependent loss of skeletal progenitors. As skeletal condensation proceeds from the shoulder to fingers (in a proximal to distal direction), the proximal elements are differentially affected in limb buds exposed to radiation at early stages. This conclusion changes the framework for considering the effect of thalidomide and other forms of phocomelia, suggesting the possibility that the etiology lies not in a defect in the patterning process, but rather in progenitor cell survival and differentiation. Moreover, molecular evidence that PD patterning is unaffected following X-irradiation does not support the predictions of the Progress Zone

Evaluation of radio-protective effect of melatonin on whole body irradiation induced liver tissue damage.

Science.gov (United States)

Shirazi, Alireza; Mihandoost, Ehsan; Ghobadi, Ghazale; Mohseni, Mehran; Ghazi-Khansari, Mahmoud

2013-01-01

Ionizing radiation interacts with biological systems to induce excessive fluxes of free radicals that attack various cellular components. Melatonin has been shown to be a direct free radical scavenger and indirect antioxidant via its stimulatory actions on the antioxidant system.The aim of this study was to evaluate the antioxidant role of melatonin against radiation-induced oxidative injury to the rat liver after whole body irradiation. In this experimental study,thirty-two rats were divided into four groups. Group 1 was the control group, group 2 only received melatonin (30 mg/kg on the first day and 30 mg/kg on the following days), group 3 only received whole body gamma irradiation of 10 Gy, and group 4 received 30 mg/kg melatonin 30 minutes prior to radiation plus whole body irradiation of 10 Gy plus 30 mg/kg melatonin daily through intraperitoneal (IP) injection for three days after irradiation. Three days after irradiation, all rats were sacrificed and their livers were excised to measure the biochemical parameters malondialdehyde (MDA) and glutathione (GSH). Each data point represents mean ± standard error on the mean (SEM) of at least eight animals per group. A one-way analysis of variance (ANOVA) was performed to compare different groups, followed by Tukey's multiple comparison tests (p<0.05). The results demonstrated that whole body irradiation induced liver tissue damage by increasing MDA levels and decreasing GSH levels. Hepatic MDA levels in irradiated rats that were treated with melatonin (30 mg/kg) were significantly decreased, while GSH levels were significantly increased, when compared to either of the control groups or the melatonin only group. The data suggest that administration of melatonin before and after irradiation may reduce liver damage caused by gamma irradiation.

Sub-micron indent induced plastic deformation in copper and irradiated steel; Deformation plastique induite par l'essai d'indentation submicronique, dans le cuivre et l'acier 316L irradie

Energy Technology Data Exchange (ETDEWEB)

Robertson, Ch

1999-07-01

In this work we aim to study the indent induced plastic deformation. For this purpose, we have developed a new approach, whereby the indentation curves provides the mechanical behaviour, while the deformation mechanisms are observed thanks to Transmission Electron Microscopy (TEM). In order to better understand how an indent induced dislocation microstructure forms, numerical modeling of the indentation process at the scale of discrete dislocations has been worked out as well. Validation of this modeling has been performed through direct comparison of the computed microstructures with TEM micrographs of actual indents in pure Cu (001]. Irradiation induced modifications of mechanical behaviour of ion irradiated 316L have been investigated, thanks to the mentioned approach. An important hardening effect was reported from indentation data (about 50%), on helium irradiated 316L steel. TEM observations of the damage zone clearly show that this behaviour is associated with the presence of He bubbles. TEM observations of the indent induced plastic zone also showed that the extent of the plastic zone is strongly correlated with hardness, that is to say: harder materials gets a smaller plastic zone. These results thus clearly established that the selected procedure can reveal any irradiation induced hardening in sub-micron thick ion irradiated layers. The behaviour of krypton irradiated 316L steel is somewhat more puzzling. In one hand indeed, a strong correlation between the defect cluster size and densities on the irradiation temperature is observed in the 350 deg. C - 600 deg. C range, thanks to TEM observations of the damage zone. On the other hand, irradiation induced hardening reported from indentation data is relatively small (about 10%) and shows no dependence upon the irradiation temperature (within the mentioned range). In addition, it has been shown that the reported hardening vanishes following appropriate post-irradiation annealing, although most of the TEM

Gamma irradiation-induced variation in carrots (Daucus carota L.)

International Nuclear Information System (INIS)

Al-Safadi, B.; Simon, P.W.

1996-01-01

Carrot tissue cultures, germinating seed, and dry seed were exposed to gamma radiation. Irradiation accelerated germination of carrot seed in the M1 generation at low doses (0.5 and 1 krad), whereas higher doses delayed germination. A high negative correlation was observed between dose and survival of plants after seed irradiation. Plant size and root weight were 20% to 35% greater than control plants after seeds, but not tissue cultures, were exposed to low doses of gamma irradiation. Higher doses reduced M1 plant size by 50% in germinating seed and tissue culture treatments but less for the dry seed treatment. Seed production decreased while phenotypic variation of M1 plants increased with increasing gamma ray dosage. Root weight and total dissolved solids were highly variable in M2 families. Less variation was observed in total carotene content and none was seen in sugar type (reducing vs. non reducing sugars). Induced variation in root color and root shape was also observed. Irradiation of germinating seed and tissue cultures yielded more M2 variation than irradiation of dry seed. Putative point mutations were not observed. Unirradiated carrot tissue cultures did not yield significant M2 somaclonal variation. Average root weight of M2 plants increased with increasing gamma ray dosage, especially for the dry seed treatment

Gamma irradiation induced variation in carrots (Daucus Carota L.)

International Nuclear Information System (INIS)

Al-Safady, B.; Simon, P.W.

1999-01-01

Carrot tissue cultures, germinating seed, and dry seed were exposed to gamma radiation. Irradiation accelerated germination of carrot seed in the M 1 generation at low doses (0.5 and 1 krad), whereas higher doses delayed germination. A high negative correlation was observed between dose and survival of plants after seed irradiation. Plant size and root weight were 20% to 35% greater than control plants after seeds, but not tissue culture, were exposed to low doses of gamma irradiation. Higher doses reduced M 1 plant size by > 50% in germinating seed and tissue culture treatments but less for the dry seed treatment. Seed production decreased while phenotypic variation of M 1 plants increased with increasing gamma ray dosage. Root weight and total dissolved solids were highly variable in M 2 families. Less variation was observed in total carotene content and none was seen in sugar type [reducing vs. non reducing sugars]. Induced variation in root color and rot shape was also observed. Irradiation of germinating seed and tissue cultures yielded more M 2 variation than irradiation of dry seed. Putative point mutations were not observed. Unirradiated carrot tissue cultures did not yield significant M 2 somaclonal variation. Average root weight of M 2 plants increased with increasing gamma ray dosage, especially for the dry seed treatment (Author)

Cyclophosphamide-induced cardiomyopathy in a patient with seminoma and a history of mediastinal irradiation

International Nuclear Information System (INIS)

Kamezaki, Kenjirou; Fukuda, Takahiro; Makino, Shigeyoshi; Harada, Mine

2005-01-01

A 17-year-old man with mediastinal seminoma was treated with chemotherapy and mediastinal irradiation therapy. Then he received high-dose chemotherapy containing cyclophosphamide (CY) followed by autologous peripheral blood stem cell transplantation. He suffered from CY-induced cardiomyopathy beginning six days after the administration of high-dose CY. The predictable factors associated with the onset of CY-induced cardiomyopathy are not precisely known. It is suggested that the history of mediastinal irradiation was responsible for the onset of cardiomyopathy. (author)

Expression and localization of Smad4 protein in mouse testis after whole-body X-ray irradiation

International Nuclear Information System (INIS)

Zhu Huaping; Zhang Yuanqiang; Zhao Jie; Zhao Yong; Ma Jing; Hou Wugang; Qi Yuhong

2005-01-01

The work is to determine whether and where Transforming growth factor-betas downstream Signaling molecule Smad4 is expressed in the testes after whole-body X-ray irradiation and shed light on the mechanisms of Transforming growth factor-betas/Smad signal pathway mediates cell fate decisions following X-ray exposure. Five groups of adult BALB/c mice, with ten mice in each group, received whole-body of X-ray at dose levels of 0.1 Gy, 0.5 Gy, 1.0 Gy, 1.5 Gy and 2.0 Gy. They were sacrificed at 16 hour, 1 week, 2 weeks, 3 weeks and 4 weeks after the irradiation. Cellular localization and expression changes were examined by immunohistochemical ABC method. Quantitative analysis of the immunostaining was made by an image analysis system. In the seminiferous tubules, the expression of Smad4 was modulated by irradiation. The immunostaining showed that 16 hour post-irradiation, there was a significant decline in the Leydig cell, and it was dose and time depended. In addition, the immunolocalization showed that Smad4 was not exclusively localized in the cytoplasm of Leydig cells, but also localized in various Stages of spermatogenesis after the exposure, especially in premeiotic spermatogonia and primary spermatocytes. There was just a little expression in the 2.0 Gy group 16 h after the irradiation and the 1.0 Gy and 1.5 Gy groups at 2 weeks after the irradiation. Therefore in the 0.1 Gy to 2.0 Gy groups at 3 weeks after the irradiation, the immunostaining positive cells were significantly increased in spermatogonia and primary spermatocytes. There was no significant change in sertoli cells with different doses and different times after the exposure. The different expression patterns and change by dose and time of Smad4, suggest that TGF-β/Smad signal pathway may affect aspect after X-ray impairment and Smad4 may play an important role during these periods. (authors)

Effect of quercetin on paracetamole-induced liver disjunction in irradiated rats

International Nuclear Information System (INIS)

Hedayat, I.S.

2005-01-01

Nowadays, increasing attention has been given to the role of free radicals generated through oxidation stress. Persons subjected to radiation, such as radiotherapy, consuming analgesic drugs such as paracetamole which accumulates at relatively high concentration in liver, are in need to be investigated to explore the synergetic effects of these stresses. Many radical scavengers, interestingly naturally occurring antioxidants, have been found to be effective in inhibiting the oxidative damage Quercetin, the well known phenolic compound widely present in the plant kingdom, has been investigated for its possible protection effect against gamma irradiation and paracetamole-induced hepatic damage. Data revealed serious effects of oral administration of sublethal dose of paracetamole (500 mg/kg) and/or exposure to 6 Gy whole body gamma irradiation on liver. This damage is reflected by increased hepatic levels of MDA, carbonyl content and ALT activity, associated by decrease in hepatic SOD, catalase and GSH when compared with respective control values. The combination of quercetin with paracetamole and/or gamma irradiation have clearly reduced liver damage. It was noticed that the restoration of peroxides and carbonyls rates has occurred. Quercetin seems to act by activation of the turnover of SOD, catalase and GSH and permitting the capitation of reactive metabolites of paracetamole as well as its ability in quenching free radicals induced by exposure of rats to gamma irradiation, thus improving regeneration in the biological tissues

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

Energy Technology Data Exchange (ETDEWEB)

Zhou, Rong [Department of Radiation Medicine, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou 730000 (China); Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Gansu Province, Lanzhou 730000 (China); Song, Jing’e [School/Hospital of stomatology, Lanzhou University, Lanzhou 730000 (China); Si, Jing [Department of Radiation Medicine, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou 730000 (China); Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Gansu Province, Lanzhou 730000 (China); Zhang, Hong, E-mail: zhangh@impcas.ac.cn [Department of Radiation Medicine, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou 730000 (China); Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Gansu Province, Lanzhou 730000 (China); Liu, Bin [School/Hospital of stomatology, Lanzhou University, Lanzhou 730000 (China); Gan, Lu; Zhou, Xin [Department of Radiation Medicine, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, Lanzhou 730000 (China); Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Gansu Province, Lanzhou 730000 (China); and others

2016-11-15

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

Effects of local and whole body irradiation on the appearance of osteoblasts during wound healing in tooth extraction sockets in rats.

Science.gov (United States)

Hosokawa, Yoichiro; Sakakura, Yasunori; Irie, Kazuharu; Kudo, Kohsei; Kashiwakura, Ikuo

2010-01-01

Irradiation before tooth extraction delays wound healing in the alveolar socket. This study examined the influences of local and whole body irradiation before tooth extraction on appearance of osteoblasts in the alveolar bone of rat maxillary first molars because bone formation is observed at the initial phase of wound healing. Several osteoblasts were generated 3 days after tooth extraction, and the number of cells increased day by day. Morphological studies showed there were little differences between local irradiation and non-irradiated controls. In contrast, the extraction wound in the whole body irradiation group showed delayed healing, and there was poor granulation tissue and very few osteoblasts at the bottom of the socket. An ultrastructural study showed that the osteoblasts in the extraction socket of whole body irradiation rats were smaller, and had poorly developed organelles. Injection of bone marrow cells to whole body-irradiated animals immediately after tooth extraction partially restored the number of osteoblasts. New periosteal bone formations outside of sockets showed little delay in the whole body irradiation group. These findings suggest that bone formation in the wound healing of extraction socket requires bone marrow cells from hematopoietic organs such as the bone marrow as well as local sources around the alveolar socket, during the initial phase of wound healing.

Effects of local and whole body irradiation on the appearance of osteoblasts during wound healing in tooth extraction sockets in rats

International Nuclear Information System (INIS)

Hosokawa, Yoichiro; Kudo, Kohsei; Kashiwakura, Ikuo; Sakakura, Yasunori; Irie, Kazuharu

2010-01-01

Irradiation before tooth extraction delays wound healing in the alveolar socket. This study examined the influences of local and whole body irradiation before tooth extraction on appearance of osteoblasts in the alveolar bone of rat maxillary first molars because bone formation is observed at the initial phase of wound healing. Several osteoblasts were generated 3 days after tooth extraction, and the number of cells increased day by day. Morphological studies showed there were little differences between local irradiation and non-irradiated controls. In contrast, the extraction wound in the whole body irradiation group showed delayed healing, and there was poor granulation tissue and very few osteoblasts at the bottom of the socket. An ultrastructural study showed that the osteoblasts in the extraction socket of whole body irradiation rats were smaller, and had poorly developed organelles. Injection of bone marrow cells to whole body-irradiated animals immediately after tooth extraction partially restored the number of osteoblasts. New periosteal bone formations outside of sockets showed little delay in the whole body irradiation group. These findings suggest that bone formation in the wound healing of extraction socket requires bone marrow cells from hematopoietic organs such as the bone marrow as well as local sources around the alveolar socket, during the initial phase of wound healing. (author)

Shift of localized surface plasmon resonance by Ar-ion irradiation of Ag–Au bimetallic films deposited on Al{sub 2}O{sub 3} single crystals

Energy Technology Data Exchange (ETDEWEB)

Meng, Xuan [Graduate School of Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628 (Japan); Shibayama, Tamaki, E-mail: shiba@qe.eng.hokudai.ac.jp [Center for Advanced Research of Energy and Materials, Faculty of Engineering, Hokkaido University, Kita-13, Nishi-8, Kita-ku, Sapporo, Hokkaido 060-8628 (Japan); Yu, Ruixuan; Takayanagi, Shinya [Graduate School of Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628 (Japan); Watanabe, Seiichi [Center for Advanced Research of Energy and Materials, Faculty of Engineering, Hokkaido University, Kita-13, Nishi-8, Kita-ku, Sapporo, Hokkaido 060-8628 (Japan)

2013-11-01

Effects of Ar-ion induced surface nanostructuring were studied using 100 keV Ar-ion irradiation of 30 nm Ag–Au bimetallic films deposited on Al{sub 2}O{sub 3} single crystals, under irradiation fluences ranging from 5.0 × 10{sup 15} cm{sup −2} to 6.3 × 10{sup 16} cm{sup −2}. Scanning electron microscope was used to study the ion-beam-induced surface nanostructuring. As the irradiation fluence increased, dewetting of the bimetallic films on the Al{sub 2}O{sub 3} substrate was observed, and formation of isolated Ag–Au nanostructures sustained on the substrate were obtained. Next, thermal annealing was performed under high vacuum at 1073 K for 2 h; a layer of photosensitive Ag–Au alloy nanoballs partially embedded in the Al{sub 2}O{sub 3} substrate was obtained when higher fluence irradiation (>3.8 × 10{sup 16} cm{sup −2}) was used. The microstructures of the nanoballs were investigated using a transmission electron microscope, and the nanoballs were found to be single crystals with a FCC structure. In addition, photoabsorption spectra were measured, and localized surface plasmon resonance peaks were observed. With increase in the irradiation fluence, the size of the Ag–Au nanoballs on the substrate decreased, and a blue-shift of the LSPR peaks was observed. Further control of the LSPR frequency over a wide range was achieved by modifying the chemical components, and a red-shift of the LSPR peaks was observed as the Au concentration increased. In summary, ion irradiation is an effective approach toward surface nanostructuring, and the nanocomposites obtained have potential applications in optical devices.

Enhanced micronucleus formation in the descendants of {gamma}-ray-irradiated tobacco cells: Evidence for radiation-induced genomic instability in plant cells

Energy Technology Data Exchange (ETDEWEB)

Yokota, Yuichiro, E-mail: yokota.yuichiro@jaea.go.jp [Life Science and Biotechnology Division, Quantum Beam Science Directorate, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan); Funayama, Tomoo; Hase, Yoshihiro [Life Science and Biotechnology Division, Quantum Beam Science Directorate, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan); Hamada, Nobuyuki [Radiation Safety Research Center, Nuclear Technology Research Laboratory, Central Research Institute of Electric Power Industry, 2-11-1 Iwado-kita, Komae, Tokyo 201-8511 (Japan); Kobayashi, Yasuhiko; Tanaka, Atsushi; Narumi, Issay [Life Science and Biotechnology Division, Quantum Beam Science Directorate, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan)

2010-09-10

Ionizing radiation-induced genomic instability has been documented in various end points such as chromosomal aberrations and mutations, which arises in the descendants of irradiated mammalian or yeast cells many generations after the initial insult. This study aimed at addressing radiation-induced genomic instability in higher plant tobacco cells. We thus investigated micronucleus (MN) formation and cell proliferation in tobacco cells irradiated with {gamma}-rays and their descendants. In {gamma}-irradiated cells, cell cycle was arrested at G{sub 2}/M phase at around 24 h post-irradiation but released afterward. In contrast, MN frequency peaked at 48 h post-irradiation. Almost half of 40 Gy-irradiated cells had MN at 48 h post-irradiation, but proliferated as actively as sham-irradiated cells up to 120 h post-irradiation. Moreover, the descendants that have undergone at least 22 generations after irradiation still showed a two-fold MN frequency compared to sham-irradiated cells. This is the direct evidence for radiation-induced genomic instability in tobacco cells.

Improvement effect of gamma-irradiated complex leaf extract of date plum, persimmon and mulberry on UVB-induced skin damage

Energy Technology Data Exchange (ETDEWEB)

Choi, Ji Won; Cho, Byoung Ok; Che, Denis Nchang; Shin, Jae Young; Fang, Chong Zhou; Jang, Seon Il [Jeonju University, Jeonju (Korea, Republic of)

2016-11-15

This study was conducted to evaluate the improvement effect of gamma-irradiated complex leaf extract of Date Plum, Persimmon and Mulberry (γ-DPME) on UVB induced skin damage. The samples were gamma irradiated at doses of 10 kGy. γ-DPME treatment tended to decrease UVB-induced immune cell infiltration and erthyderma index than the groups treated with non-gamma-irradiated DPME (n-DPME) and L-ascobic acid (AA). In addition, γ-DPME treatment significantly decreased skin thickness, melanin index and mast cell infiltration in UVB-irradiated skin. Moreover, γ-DPME treatment significantly decreased the compound 48/80-induced scratching behavior and immune cell infiltration than n-DPME group. These results show that gamma irradiation can be used to increase the physiological activities of DPME.

Radiation effect and response of DNA synthesis in lymphocytes induced by low dose irradiation

International Nuclear Information System (INIS)

Zhao Yujie; Su Liaoyuan; Zou Huawei; Kong Xiangrong

1999-01-01

The ability of DNA synthesis in lymphocytes were measured by using 3 H-TdR incorporation method. This method was used to observe the damage of lymphocytes irradiated by several challenge doses (0.5-0.8 Gy) and adaptive response induced by previous low dose irradiation. The results show that DNA synthesis was inhibited by challenge dose of radiation and was adapted by previous 0.048 Gy irradiation

Radiation effects on regeneration and T-cell-inducing function of the thymus

International Nuclear Information System (INIS)

Hirokawa, K.; Sado, T.

1984-01-01

Radiation effects on regeneration and T-cell-inducing function of the thymus were studied in three sets of experiments. When TXB mice were grafted with 1-week-old thymus which had been previously irradiated at various doses, an exponential decrease was observed in the morphological regeneration of the thymus grafts and in their T-cell-inducing function at doses of 600 R and over, showing about 10% that of the control at 1500 R. When in situ thymus of adult mice was locally irradiated, the radiation effect on T-cell-inducing function was less pronounced as compared with the first experiment; i.e., about 40% of the control at 1797 R. When in situ thymus of 1-day-old newborn mice was locally irradiated, regeneration potential of 1-day-old newborn thymus was highly resistant to radiation exposure and no effect on immunological functions was observed even by local irradiation of 2000 R

Pathological response of locally advanced rectal cancer to preoperative chemotherapy without pelvic irradiation.

Science.gov (United States)

Bensignor, T; Brouquet, A; Dariane, C; Thirot-Bidault, A; Lazure, T; Julié, C; Nordlinger, B; Penna, C; Benoist, S

2015-06-01

Pathological response to chemotherapy without pelvic irradiation is not well defined in rectal cancer. This study aimed to evaluate the objective pathological response to preoperative chemotherapy without pelvic irradiation in middle or low locally advanced rectal cancer (LARC). Between 2008 and 2013, 22 patients with middle or low LARC (T3/4 and/or N+ and circumferential resection margin rectal resection after preoperative chemotherapy. The pathological response of rectal tumour was analysed according to the Rödel tumour regression grading (TRG) system. Predictive factors of objective pathological response (TRG 2-4) were analysed. All patients underwent rectal surgery after a median of six cycles of preoperative chemotherapy. Of these, 20 (91%) had sphincter saving surgery and an R0 resection. Twelve (55%) patients had an objective pathological response (TRG 2-4), including one complete response. Poor response (TRG 0-1) to chemotherapy was noted in 10 (45%) patients. In univariate analyses, none of the factors examined was found to be predictive of an objective pathological response to chemotherapy. At a median follow-up of 37.2 months, none of the 22 patients experienced local recurrence. Of the 19 patients with Stage IV rectal cancer, 15 (79%) had liver surgery with curative intent. Preoperative chemotherapy without pelvic irradiation is associated with objective pathological response and adequate local control in selected patients with LARC. Further prospective controlled studies will address the question of whether it can be used as a valuable alternative to radiochemotherapy in LARC. Colorectal Disease © 2014 The Association of Coloproctology of Great Britain and Ireland.

Effect of salt-inducible kinase 2 on checkpoint in response to γ-ray irradiation

International Nuclear Information System (INIS)

Yin Jiaojiao; Zhou Lijun; Wang Yu; Liu Xiaodan; Gu Yongqing; Zhou Pingkun

2014-01-01

Objective: To investigate the effect of salt-induced kinase 2 (SIK2) in the G_2/M checkpoint in response to ionizing radiation and the possible mechanism. Methods: HeLa cells were irradiated with "6"0Co γ-rays. The cell model of knockdown SIK2 expression was constrcuted by transfecting HeLa cells with a pSicoR-based lentivirus vector of expressing SIK2 shRNA by lipofectamin 2000. Western blot and flow cytometry were performed to measure the changes of SIK2 protein level and cell cycle distribution. The phosphorylated histone protein H3 on Ser 10 was used as a molecular marker of mitotic cells for detecting the function of G2/M checkpoint. Results: The expression level of SIK2 protein increased in HeLa cells after "6"0Co γ-ray irradiation. A cell model of knockdown SIK2 expression was successfully generated by transfecting the specific shRNA against SIK2. Depression of SIK2 significantly increased the cellular sensitivity at 1, 2, 4, 6 Gy post-irradiation (t = -3.445, -2.581, -3.251, -2.553, P < 0.05), and led cells to release earlier from the G_2/M boundary arrest compared to control cells at 5, 6 h post-irradiation(t = 4.341, 6.500, P < 0.05). Western blot analysis indicated that the irradiation-induced phosphorylated CHK2/T68 in SIK2 knock-down cells was earlier than that in control cells. Conclusions: salt-induced kinase 2 (SIK2) participates in the regulation of G_2/M checkpoint induced by ionizing radiation and affects cellular radiosensitivity. (authors)

Radiation induced coloring of glasses measured during and after electron irradiation

International Nuclear Information System (INIS)

Swyler, K.J.; Hardy, W.H. II; Levy, P.W.

1975-01-01

The growth of color centers during irradiation, and the decay after irradiation, were studied in two glasses using recently developed equipment for making optical absorption and luminescence measurements during and after electron irradiation. The glasses studied were NBS 710, a soda-lime silicate glass, and NBS 711, a lead silicate glass. Both glasses exhibit similar coloring characteristics. The radiation-induced absorption spectra consists of a weak gaussian shaped band in the visible, a stronger gaussian band in the ultraviolet, and a band edge ''shift'' which may be accurately approximated by a third gaussian band. For all absorption bands, the color center vs dose (or irradiation time) curves can be accurately resolved into two saturating exponential and one linear component. The decay curves obtained after the irradiation is terminated can be accurately expressed by three exponential components. Coloring and decay curves made at different dose rates indicate that the processes responsible for decay after irradiation and electron hole recombination during irradiation play important roles in determining the rate and extent of coloring. Results are qualitatively in agreement with some very simple kinetic treatments for color center formation. In some, but not all, respects the quantitative agreement is also good. Lastly, the results indicate that it is necessary to make measurements during irradiation to establish the formation kinetics of color centers that are unstable at the bombardment temperature. (U.S.)

Electron-irradiation induced changes in structural and magnetic properties of Fe and Co based metallic glasses

Energy Technology Data Exchange (ETDEWEB)

Kane, S.N., E-mail: kane_sn@yahoo.com [School of Physics, D.A. University, Khandwa Road Campus, Indore 452001 (India); Satalkar, M., E-mail: satalkar.manvi@gmail.com [School of Physics, D.A. University, Khandwa Road Campus, Indore 452001 (India); Ghosh, A.; Shah, M. [School of Physics, D.A. University, Khandwa Road Campus, Indore 452001 (India); Ghodke, N. [UGC-DAE CSR, University Campus, Khandwa Road, Indore 452001 (India); Pramod, R.; Sinha, A.K.; Singh, M.N.; Dwivedi, J. [Raja Ramanna Centre for Advanced Technology, P.O. CAT, Indore 452013 (India); Coisson, M.; Celegato, F.; Vinai, F.; Tiberto, P. [INRIM, Electromagnetism Division, Strada Delle Cacce 91, I-10135 TO (Italy); Varga, L.K. [RISSPO, Hungarian Academy of Sciences, P.O. Box 49, 1525 Budapest (Hungary)

2014-12-05

Highlights: • Enhancement of Ms by low electron irradiation dose in Fe-based alloy. • Variation of magnetic properties by electron irradiation induced ordered phase. • Electron irradiation alters TM-TM distance and, magnetic properties. - Abstract: Electron-irradiation induced changes in structural and, magnetic properties of Co{sub 57.6}Fe{sub 14.4}Si{sub 4.8}B{sub 19.2}Nb{sub 4}, Fe{sub 72}Si{sub 4.8}B{sub 19.2}Nb{sub 4} and, Co{sub 72}Si{sub 4.8}B{sub 19.2}Nb{sub 4} metallic glasses were studied using magnetic hysteresis and, synchrotron X-ray diffraction measurements. Results reveal composition dependent changes of magnetic properties in electron irradiated metallic glasses. A low electron irradiation dose (15 kGy) enhances saturation magnetization (up to 62%) in Fe-based alloy (Fe{sub 72}Si{sub 4.8}B{sub 19.2}Nb{sub 4}). Synchrotron XRD measurements reveal that electron irradiation transforms the amorphous matrix to a more ordered phase, accountable for changes in magnetic properties.

Effects of wearing bio-active material coated fabric against γ-irradiation-induced cellular damaged in Sprague-Dawley rats

International Nuclear Information System (INIS)

Kang, Jung Ae; Kim, Hye Rim; Yoon, Sun Hye; Nam, Sang Hyun; Park, Sang Hyun; Jang, Beom Su; Go, Kyung Chan; Yang, Gwang Wung; Rho, Young Hwan; Park, Hyo Suk

2016-01-01

Ionizing radiation causes cellular damage and death through the direct damage and/or indirectly the production of ROS, which induces oxidative stress. This study was designed to evaluate the in vivo radioprotective effects of a bio-active material coated fabric (BMCF) against γ-irradiation-induced cellular damage in Sprague-Dawley (SD) rats. Healthy male SD rats wore bio-active material coated (concentrations in 10% and 30%) fabric for 7 days after 3 Gy of γ-irradiation. Radioprotective effects were evaluated by performing various biochemical assays including spleen and thymus index, WBC count, hepatic damage marker enzymes [aspartate transaminase (AST) and alanine transaminase (ALT)] in plasma, liver antioxidant enzymes, and mitochondrial activity in muscle. Exposure to γ-irradiation resulted in hepatocellular and immune systemic damage. Gamma-irradiation induced decreases in antioxidant enzymes. However, wearing the BMCF-30% decreased significantly AST and ALT activities in plasma. Furthermore, wearing the BMCF-30% increased SOD (superoxide dismutase) and mitochondrial activity. These results suggest that wearing BMCF offers effective radioprotection against γ-irradiation-induced cellular damage in SD rats

Effects of wearing bio-active material coated fabric against γ-irradiation-induced cellular damaged in Sprague-Dawley rats

Energy Technology Data Exchange (ETDEWEB)

Kang, Jung Ae; Kim, Hye Rim; Yoon, Sun Hye; Nam, Sang Hyun; Park, Sang Hyun; Jang, Beom Su [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of); Go, Kyung Chan; Yang, Gwang Wung; Rho, Young Hwan; Park, Hyo Suk [Research and Development Center, VENTEX Co. Ltd., Seoul (Korea, Republic of)

2016-09-15

Ionizing radiation causes cellular damage and death through the direct damage and/or indirectly the production of ROS, which induces oxidative stress. This study was designed to evaluate the in vivo radioprotective effects of a bio-active material coated fabric (BMCF) against γ-irradiation-induced cellular damage in Sprague-Dawley (SD) rats. Healthy male SD rats wore bio-active material coated (concentrations in 10% and 30%) fabric for 7 days after 3 Gy of γ-irradiation. Radioprotective effects were evaluated by performing various biochemical assays including spleen and thymus index, WBC count, hepatic damage marker enzymes [aspartate transaminase (AST) and alanine transaminase (ALT)] in plasma, liver antioxidant enzymes, and mitochondrial activity in muscle. Exposure to γ-irradiation resulted in hepatocellular and immune systemic damage. Gamma-irradiation induced decreases in antioxidant enzymes. However, wearing the BMCF-30% decreased significantly AST and ALT activities in plasma. Furthermore, wearing the BMCF-30% increased SOD (superoxide dismutase) and mitochondrial activity. These results suggest that wearing BMCF offers effective radioprotection against γ-irradiation-induced cellular damage in SD rats.

The irradiation embrittlement of two pressure vessel steels -Contribution of local approach

Energy Technology Data Exchange (ETDEWEB)

Soulat, P; Marini, B [CEA Centre d` Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France). Service de Recherches Metallurgiques Appliquees; Miannay, D; Horowitz, H [CEA Centre d` Etudes de Fontenay-aux-Roses, 92 (France). Inst. de Protection et de Surete Nucleaire; Schill, R [CEA Centre d` Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. de Mecanique et de Technologie

1994-12-31

Within the IAEA Coordinated Research Programme on ``Optimizing the Reactor Pressure Vessel Surveillance Programmes and their Analyses``, the French participation has been focused on the contribution of the local approach to the determination of the sensitivity to radiation embrittlement of two different pressure vessel steels: a low sensitive French forging steel (FFA) and a high sensitive ``monitor`` Japanese plate steel (JRQ) were irradiated to a fluence of 3.10{sup 19} n/cm{sup 2} at 290 C. The irradiation embrittlement of the two steels measured by the shift of Charpy V transition curves is in good agreement with the estimated shifts given by theoretical prediction. The fracture toughness properties were examined at low temperature with brittle fracture, and at service temperature (290 C), with ductile tearing. The values of K{sub 1C} or K{sub JC} for the brittle fracture and J{sub 1C} for the ductile fracture are compared to predictions established using the local approach of cleavage fracture (Weibull analysis) and the critical rate of void growth respectively. 8 refs., 14 figs., 10 tabs.

Cytosine arabinoside enhancement of gamma irradiation induced mutations in human T-lymphocytes

International Nuclear Information System (INIS)

O'Neill, J.P.; Sullivan, L.M.; Hunter, T.C.; Nicklas, J.A.

1991-01-01

The frequency of 6-thioguanine resistant (TGr) mutants induced in human G0 phase T-lymphocytes by 200 cGy of gamma irradiation is greatly enhanced by incubation with cytosine arabinoside (ara-C) after irradiation. The mutant frequency increased with increasing incubation time in ara-C for up to 2 hr. This mutation induction required a phenotypic expression time of 5-8 days mass culture growth, similar to that found with mutants induced by 300 cGy of irradiation alone. Southern blot analysis of 40 isolated mutant clones revealed 8 independent mutations by T-cell receptor (TCR) gene rearrangement patterns. Four of these eight showed hprt gene structural alterations (0.50). An alternative method to allow phenotypic expression was developed to minimize the isolation of hprt/TCR sibling mutants. The use of in situ expression in the microtiter dish wells resulted in the isolation of 17 independent mutations in 19 mutant clones. Ten of these 17 mutations showed hprt structural alterations (0.59). The high fraction of mutations involving structural alterations detected by Southern blot analysis is consistent with the known induction of chromosome aberrations by irradiation plus ara-C treatment. We propose that both the increase in Mf and the increase in the incidence of hprt gene structural alterations are due to the accumulation of strand breaks in repairing regions of DNA under these conditions of ara-C induced inhibition of repair. We further propose that upon release of the ara-C inhibition, these repairing regions can interact to yield both gene mutations and chromosome aberrations

Fundamental Studies of Irradiation-Induced Modifications in Microstructural Evolution and Mechanical Properties of Advanced Alloys

Energy Technology Data Exchange (ETDEWEB)

Stubbins, James; Heuser, Brent; Hosemann, Peter; Liu, Xiang

2018-04-24

This final technical report summarizes the research performed during October 2014 and December 2017, with a focus on investigating the radiation-induced microstructural and mechanical property modifications in optimized advanced alloys for sodium-cooled fast reactor (SFR) structural applications. To accomplish these objectives, the radiation responses of several different advanced alloys, including austenitic steel Alloy 709 (A709) and 316H, and ferritic/ martensitic Fe–9Cr steels T91 and G92, were investigated using a combination of microstructure characterizations and nanoindentation measurements. Different types of irradiation, including ex situ bulk ion irradiation and in situ transmission electron microscopy (TEM) ion irradiation, were employed in this study. Radiation-induced dislocations, precipitates, and voids were characterized by TEM. Scanning transmission electron microscopy with energy dispersive X-ray spectroscopy (STEM-EDS) and/or atom probe tomography (APT) were used to study radiation-induced segregation and precipitation. Nanoindentation was used for hardness measurements to study irradiation hardening. Austenitic A709 and 316H was bulk-irradiated by 3.5 MeV Fe++ ions to up to 150 peak dpa at 400, 500, and 600°. Compared to neutron-irradiated stainless steel (SS) 316, the Frank loop density of ion-irradiated A709 shows similar dose dependence at 400°, but very different temperature dependence. Due to the noticeable difference in the initial microstructure of A709 and 316H, no systematic comparison on the Frank loops in A709 vs 316H was made. It would be helpful that future ion irradiation study on 316 stainless steel could be conducted to directly compare the temperature dependence of Frank loop density in ion-irradiated 316 SS with that in neutron-irradiated 316 SS. In addition, future neutron irradiation on A709 at 400–600° at relative high dose (>10 dpa) can be carried out to compare with ion-irradiated A709. The radiation-induced

Molecular and genetic approach to understanding the mechanisms by which fractionated X-irradiation induces leukemia in mice

Energy Technology Data Exchange (ETDEWEB)

Meruelo, D; Rossomando, A

1986-01-01

The authors laboratory's approach to try to shed light on the question of a viral etiology for radiation-induced leukemia has focused on defining, localizing and understanding the mode of action of genes involved in susceptibility to fractionated x-irradiation-(FXI) induced disease. These studies have indicated that multiple genes control the process of leukemogenesis. Not every mouse strain which shows some susceptibility to FXI-induced leukemia carries the susceptible gene at each of the multiple loci involved in the disease process. It is plausible to conclude that more than one mechanism of leukemogenesis can be triggered by FXI. Studies have focused on the mode of action of one such locus Ril-1. Several reagents have been developed to help clone and characterize this locus. Currently chromosomal ''walking'' and ''hopping'' techniques are being used in conjunction with an RFLP molecular probe which is adjacent to Ril-1. In addition a cDNA library has been prepared from a radiation-induced thymoma and substraction hybridization analysis is being used in the search for Ril-1.

Post-irradiation dietary vitamin E does not affect the development of radiation-induced lung damage in rats

International Nuclear Information System (INIS)

Wiegman, Erwin M.; Gameren, Mieke M. van; Kampinga, Harm H.; Szabo, Ben G.; Coppes, Rob P.

2004-01-01

The purpose of this study was to investigate whether application of post-irradiation vitamin E, an anti-oxidant, could prevent the development of radiation induced lung damage. Wistar rats were given vitamin E enriched or vitamin E deprived food starting from 4 weeks after 18 Gy single dose irradiation of the right thorax. Neither breathing frequencies nor CT density measurements revealed differences between the groups. It is concluded that post-irradiation vitamin E does not influence radiation-induced fibrosis to the lung

EFFICIENCY OF BORAGE SEEDS OIL AGAINST GAMMA IRRADIATION-INDUCED HEPATOTOXICITY IN MALE RATS: POSSIBLE ANTIOXIDANT ACTIVITY.

Science.gov (United States)

Khattab, Hala A H; Abdallah, Inas Z A; Yousef, Fatimah M; Huwait, Etimad A

2017-01-01

Borage ( Borago officinal L.) is an annual herbaceous plant of great interest because its oil contains a high percentage of γ-linolenic acid (GLA). The present work was carried out to detect fatty acids composition of the oil extracted from borage seeds (BO) and its potential effectiveness against γ-irradiation- induced hepatotoxicity in male rats. GC-MS analysis of fatty acids methyl esters of BO was performed to identify fatty acids composition. Sixty rats were divided into five groups (12 rats each): Control, irradiated; rats were exposed to (6.5 Gy) of whole body γ-radiation, BO (50 mg/kg b.wt), irradiated BO post-treated and irradiated BO prepost-treated. Six rats from each group were sacrificed at two time intervals 7 and 15 days post-irradiation. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma glutamyl transferase (GGT) levels, lipids profile, as well as serum and hepatic reduced glutathione (GSH) and lipid peroxide (malondialdehyde) (MDA) levels were assessed. Histopathological examination of liver sections were also carried out. The results showed that the high contents of BO extracted by cold pressing, were linoleic acid (34.23%) and GLA (24.79%). Also, oral administration of BO significantly improved serum levels of liver enzymes, lipids profile, as well as serum and hepatic GSH and MDA levels (p<0.001) as compared with irradiated rats after 15 days post irradiation. Moreover, it exerted marked amelioration against irradiation-induced histopathological changes in liver tissues. The improvement was more pronounced in irradiated BO prepost-treated group than irradiated BO post-treated. BO has a beneficial role in reducing hepatotoxicity and oxidative stress induced by radiation exposure. Therefore, BO may be used as a beneficial supplement for patients during radiotherapy treatment.

Glucidic and lipidic metabolic changes in rats induced by irradiation and the effect of adrenalectomy

Energy Technology Data Exchange (ETDEWEB)

Groza, P; Ghizari, E; Butculescu, I; Ciontescu, L; Ciuntu, L

1975-01-01

In experiments on X-irradiated rats (1000 R) the hepatic glycogen, total lipids, phospholipids content, and plasma glucose, cholesterol and beta-lipoprotein concentration were determined in intact and adrenalectomized animals. It was confirmed that irradiation produces a hepatic glycogen and blood glucose increased concentration. The glucidic metabolic response on irradiation is diminished by adrenalectomy. The adrenalectomy-induced modifications in the lipid metabolism of irradiated rats are more inconstant, which corresponds with its relative independence from glucocorticoid hormones.

Acute irradiation and muscular fibrosis. Development and characteristics in the pig

International Nuclear Information System (INIS)

Lefaix, J.L.; Daburon, F.; Remy, J.

1989-01-01

This study was performed in an experimental porcin model of acute local irradiation chosen to simulate human accidents. It enabled to determine the development and the physiopathological characteristics of the fibrous tissue which developed in skeletal muscle. In the first month after irradiation the strong inflammatory reaction initiating the radiation induced fibrosis was characterized by edema as visualized on NMR imaging and by acute phase reactant protein changes, associated with elevations of local and general temperatures in irradiated animals. At the margin of the irradiated tissue, atypical fibroblasts isolated among collagen bundles or bunched in nodullary reinforcement were seen associated with intense capillary neogenesis. Several months after irradiation normal skeletal muscle was replaced by atrophic fibrosis delimited by an inflammatory perifibrotic tissue. The muscular fibrosis was characterized by a high atypical fibroblasts density and by an inflammatory distribution pattern of collagen types I, III, IV, laminin, fibronectin and fibrinogen as visualized by immunohistochemical methods. Biochemical results showed an increase in collagen content and synthesis in fibrotic tissue whereas perifibrotic zone synthesized more non collagenous proteins compared with the normal muscle. The contributions of granulation tissue, cellular mediators and inhibition of muscular regeneration to maintain the atrophic character of the muscular radiation induced fibrosis are discussed [fr

Irradiation With Carbon Ion Beams Induces Apoptosis, Autophagy, and Cellular Senescence in a Human Glioma-Derived Cell Line

International Nuclear Information System (INIS)

Jinno-Oue, Atsushi; Shimizu, Nobuaki; Hamada, Nobuyuki; Wada, Seiichi; Tanaka, Atsushi; Shinagawa, Masahiko; Ohtsuki, Takahiro; Mori, Takahisa; Saha, Manujendra N.; Hoque, Ariful S.; Islam, Salequl; Kogure, Kimitaka; Funayama, Tomoo; Kobayashi, Yasuhiko

2010-01-01

Purpose: We examined biological responses of human glioma cells to irradiation with carbon ion beams (C-ions). Methods and Materials: A human glioma-derived cell line, NP-2, was irradiated with C-ions. Apoptotic cell nuclei were stained with Hoechst 33342. Induction of autophagy was examined either by staining cells with monodansylcadaverine (MDC) or by Western blotting to detect conversion of microtuble-associated protein light chain 3 (MAP-LC3) (LC3-I) to the membrane-bound form (LC3-II). Cellular senescence markers including induction of senescence-associated β-galactosidase (SA-β-gal) were examined. The mean telomere length of irradiated cells was determined by Southern blot hybridization. Expression of tumor suppressor p53 and cyclin/cyclin-dependent kinase inhibitor p21 WAF1/CIP1 in the irradiated cells was analyzed by Western blotting. Results: When NP-2 cells were irradiated with C-ions at 6 Gy, the major population of the cells died of apoptosis and autophagy. The residual fraction of attached cells ( WAF1/CIP1 was induced in NP-2 cells after irradiation. Furthermore, we found that irradiation with C-ions induced cellular senescence in a human glioma cell line lacking functional p53. Conclusions: Irradiation with C-ions induced apoptosis, autophagy, and cellular senescence in human glioma cells.

Detection of radiation-induced hydrocarbons in baked sponged cake prepared with irradiated liquid egg

Science.gov (United States)

Schulzki, G.; Spiegelberg, A.; Bögl, K. W.; Schreiber, G. A.

1995-02-01

For identification of irradiated food, radiation-induced volatile hydrocarbons (HC) are determined by gas chromatography in the non-polar fraction of fat. However, in complex food matrices the detection is often disturbed by fat-associated compounds. On-line coupling of high performance liquid chromatography (LC) and gas chromatography (GC) is very efficient to remove such compounds from the HC fraction. The high sensitivity of this fast and efficient technique is demonstrated by the example of detection of radiation-induced HC in fat isolated from baked sponge cake which had been prepared with irradiated liquid egg.

The effect of X-irradiation on the fertility and the induction of meiotic chromosome rearrangements in mice and their first generation

International Nuclear Information System (INIS)

Savkovic, N.; Pecevski, J.; Maric, N.; Radivojevic, D.

1978-01-01

The effect of whole-body and local irradiation with a dose of 600 X-rays on the induction of chromosomal translocations in Diakinesis-Metaphase I of meiosis in treated and F 1 males and their fertility have been examined. Our results showed the high percentage of mortality in whole-body irradiated mice. The percentage of fertility was 25% in whole-body, and 93,7% in locally irradiated males. The testis weight was also reduced. The percentage of chromosomal translocations in Diakinesis-Metaphase I of meiosis was greater after whole-body than after local irradiation. In F 1 males both types of irradiation induced chromosomal translocations. (orig.) [de

Investigations of Atomic Transport Induced by Heavy Ion Irradiation

Science.gov (United States)

Banwell, Thomas Clyde

The mechanisms of atomic transport induced by ion irradiation generally fall into the categories of anisotropic or isotropic processes. Typical examples of these are recoil implantation and cascade mixing, respectively. We have measured the interaction of these processes in the mixing of Ti/SiO(,2)/Si, Cr/SiO(,2)/Si and Ni/SiO(,2)/Si multi-layers irradiated with Xe at fluences of 0.01 - 10 x 10('15)cm('-2). The fluence dependence of net metal transport into the underlying layers was measured with different thicknesses of SiO(,2) and different sample temperatures during irradiation (-196 to 500C). There is a linear dependence at low fluences. At high fluences, a square-root behavior predominates. For thin SiO(,2) layers (primary recoils is quite pronounced since the gross mixing is small. A significant correlation exists between the mixing and the energy deposited through elastic collisions F(,D ). Several models are examined in an attempt to describe the transport process in Ni/SiO(,2). It is likely that injection of Ni by secondary recoil implantation is primarily responsible for getting Ni into the SiO(,2). Secondary recoil injection is thought to scale with F(,D). Trends in the mixing rates indicate that the dominant mechanism for Ti and Cr could be the same as for Ni. The processes of atomic transport and phase formation clearly fail to be separable at higher temperatures. A positive correlation with chemical reactivity emerges at higher irradiation temperatures. The temperature at which rapid mixing occurs is not much below that for spontaneous thermal reaction. Less Ni is retained in the SiO(,2) at high irradiation temperatures. Ni incorporated in the SiO(,2) by low temperature irradiation is not expelled during a consecutive high temperature irradiation. The Ni remains trapped within larger clusters during a sequential 500C irradiation. (Abstract shortened with permission of author.).

TNF, IL-1 and IL-6 in circulating blood after total-body and localized irradiation in rats

NARCIS (Netherlands)

Haveman, J.; Geerdink, A. G.; Rodermond, H. M.

1998-01-01

The levels of TNF, IL-1 and IL-6 in circulating blood of female WAG/Rij rats were assessed both after total-body irradiation (TBI) and localized irradiation of the right hind leg. The results show that enhanced levels of IL-1 in the circulation reflect a stress situation presumably resulting from

Deuterium ion irradiation induced blister formation and destruction

Energy Technology Data Exchange (ETDEWEB)

Song, Jaemin; Kim, Nam-Kyun; Kim, Hyun-Su; Jin, Younggil; Roh, Ki-Baek; Kim, Gon-Ho, E-mail: ghkim@snu.ac.kr

2016-11-01

Highlights: • The areal number density of blisters on the grain with (1 1 1) plane orientation increased with increasing ion fluence. • No more blisters were created above the temperature about 900 K due to high thermal mobility of ions and inactivity of traps. • The destruction of blister at the boundary induced by sputtering is proposed. • The blisters were destructed at the position about the boundary by high sputtering yield of oblique incident ions and thin thickness due to plastic deformation at the boundary. - Abstract: The blisters formation and destruction induced by the deuterium ions on a polycrystalline tungsten were investigated with varying irradiation deuterium ion fluence from 3.04 × 10{sup 23} to 1.84 × 10{sup 25} D m{sup −2} s{sup −1} and an fixed irradiated ion energy of 100 eV in an electron cyclotron resonance plasma source, which was similar to the far-scrape off layer region in the nuclear fusion reactors. Target temperature was monitored during the irradiation. Most of blisters formed easily on the grain with (1 1 1) plane orientation which had about 250 nm in diameter. In addition, the areal number density of blisters increased with increasing the ion fluence under the surface temperature reaching to about 900 K. When the fluence exceeded 4.6 × 10{sup 24} D m{sup −2}, the areal number density of the blister decreased. It could be explained that the destruction of the blister was initiated by erosion at the boundary region where the thickness of blister lid was thin and the sputtering yield was high by oblique incident ions, resulting in remaining the lid open, e.g., un-eroded center dome. It is possible to work as a tungsten dust formation from the plasma facing divertor material at far-SOL region of fusion reactor.

Modulation of Immune Disorders Induced-Arthritis in γ- Irradiated Rats

International Nuclear Information System (INIS)

Thabet, N.M.S.

2013-01-01

This study was to evaluate the antioxidant and anti-inflammatory capability of a laboratory preparation mixture Nano Selenium-lovastatin (Lov-Se) against oxidative stress and inflammatory cascade in irradiated and/or adjuvant arthritic rats. The experimental animals were divided into: adjuvant free groups and adjuvant induced groups. Rats were exposed to whole body γ-radiation (2 Gy every 3 days up to total dose of 8 Gy) and received oral administration of 1 ml Lov-Se mixture (≈ 20 mg kg - 1 Lov and 0.1 mg kg - 1 day - 1 Se) for 14 successive days. Animal model of arthritis was organized by subcutaneous injection of complete freund’s adjuvant. The antioxidant parameters (heart GSH-Px, CAT, SOD, XDH, GSH and blood Se), and oxidant markers (heart XO, NO, protein carbonyls and TBARS) and Also, the inflammatory molecules (serum TNF-α, CRP and RF) were determined. In irradiated Lov-Se rats, the results obtained reveals that, TBARS, protein carbonyl, TNF-α, CRP levels, and XO, CAT and SOD activities were significantly ameliorated as compared to irradiated rats. Also, heart GSH, NO levels, XDH, GSH-Px activities and blood Se level were significantly improved. In addition, the administration of Lov-Se to the arthritic and arthritic irradiated rats ameliorates the disturbance occurs in oxidative stress, inflammatory cascades and antioxidant indicators when compared to control rats. In conclusion, the proper administration of Lov-Se mixture might reduce the radiation-induced heart injury via amending the antioxidant molecules and decreasing lipid and protein oxidation. Also, it could be suggested that Lov-Se mixture might posses a considerable anti-inflammatory properties

Hassall's corpuscles in the guinea-pig thymus after a second 60Co local irradiation

International Nuclear Information System (INIS)

Kinoshita, Hideo

1974-01-01

The cervical regions of male guinea-pigs, weighing about 300 g, were irradiated locally with 60 Co 800 R, and the same dose of irradiation was repeated a second time in each guinea pig at a different interval. Thereafter, an irradiated animal was sacrificed every other day for 2 weeks. Thymuses were weighed and fixed in 10 percent formal saline. Tissues were blocked in paraffin and each block was cut into serial sections having a thickness of approximately 6 microns. These sections were stained with the haematoxylin-eosin (HE) and the aldehyde-fuchsin (AF) techniques. The size of Hassall's corpuscles was measured in the sections of HE and the AF (+) ratio of Hassall's corpuscles was calculated in sections of AF. The ratio (%) of the number of AF (+) corpuscles to the total number of corpuscles seen in the entire microscopical field was called ''AF (+) ratio''. The weight of the twice irradiated thymuses decreased regardless of the interval from the first irradiation. The tendency of Hassall's corpuscles to enlarge during the period of enlargement of the corpuscles after first irradiation was increased by the second irradiation. The enlarged pattern of Hassall's corpuscles after a single irradiation of 60 Co 800 R re-appeared when the animals were given a second irradiation on the 35th day. Concerning the AF (+) ratio of Hassall's corpuscles, the increasing pattern of AF (+) ratio such as after single irradiation of 60 Co 800 R re-appeared when the animals were given a second irradiation on the 35th day, but no effect was observed during the process of enlargement and disintegration of Hassall's corpuscles after the second irradiation. The enlargement of Hassall's corpuscles is attributed not only to the process of lympholysis, but also to various other factors such as the number and size of the corpuscles and the stage in their life cycle. (JPN)

Studies on adaptive response of lymphocyte transformation induced by low-dose irradiation

International Nuclear Information System (INIS)

Du Zeji; Su Liaoyuan; Tian Hailin; Zou Huawei

1995-10-01

Human peripheral blood lymphocytes stimulated by mitogen in vitro for 24 h were exposed to low-dose γ-ray irradiation (0.5∼4.0 cGy, adaptive dose). They showed an adaptive response to the inhibition of 3 H-TdR incorporation by subsequent higher acute doses of γ-ray (challenge dose). At the interval of 24 h between adaptive dose and challenge dose, the strongest adaptive response induced by low-dose irradiation was found. It is also found that the response induced by 1.0 cGy of adaptive dose was more obvious than that by other doses and that 3.0 Gy of challenge dose produced the strongest adaptive response. As the challenge doses increased, the adaptive response reduced. (2 figs., 2 tabs.)

Expression of p53, MDM2 in a mice hydradecarcinoma model induced by γ-ray irradiation

International Nuclear Information System (INIS)

Huang Yuecheng; Cai Jianming; Han Ling; Gao Fu; Sun Ding; Dong Zhitao; Zhe Wanli

2004-01-01

Objective: To investigate the role of the p53, MDM2 in carcinogenesis of mice hydradecarcinoma induced by γ-rays. Methods: A radiation-induced mice hydradecarcinoma model was established by γ-ray irradiation. Expression of MDM2 protein in hydradecarcinoma tissue, paracancerous tissue and normal control tissue was detected with Western blot. Immunoprecipitation (IP) was conducted to examine the phosphorylation level of MDM2 protein. PCR-SSCP was performed to detect p53 gene mutation. Results: Compared with the normal control tissue, the MDM2 protein expression and its phosphorylation level were significantly higher in hydradecarcinoma tissue. SSCP showed there were p53 gene mutations in hydradecarcinoma samples. Conclusion: p53/MDM2 pathway may be involved in the development and progression of hydradecarcinoma induced by γ-ray irradiation. The over-expression of MDM2 and hyperphosphorylation may be responsible for malignant transformation induced by irradiation by a possible mechanism of p53 inactivation. The gene mutation of p53 further supported the hypothesis that p53/MDM2 pathway played a central role in carcinogenesis of γray induced hydradecarcinoma. (authors)

Persistent genetic instability induced by synergistic interaction between x-irradiation and 6-thioguanine

International Nuclear Information System (INIS)

Grosovsky, A.J.; Nelson, S.L.; Smith, L.E.

1995-01-01

Clonal karyotypic analysis was performed using G-banding on four groups of clones derived from TK6 human lymphoblasts: 25 HPRT - total gene deletion mutants induced by exposure to 2 Gy of x-rays; 8 spontaneous HPRT - total gene deletion mutants; 25 clones irradiated with 2 Gy, not selected with 6-thioguanine. Ten to twenty metaphases were examined for each clone. Extensive karyotypic heterogeneity was observed among x-ray induced HPRT - mutants involving translocations, deletions, duplications and aneuploidy; recovery of chromosomal aberrations and karyotypic heterogeneity was greater than the additive effects of clones treated with x-irradiation or 6-thioguanine alone. This synergistic interaction between x-irradiation and 6-thioguanine was observed despite a 7 day phenotypic expression interval between exposure to the two agents. Thus, x-irradiated TK6 cells appear to be persistently hypersensitive to the induction of genetic instability. Several mutants appeared to exhibit evidence of clonal evolution since aberrant chromosomes observed in one metaphase, were found to be further modified in other metaphases. In order to determine if genetic instability, identified by clonal karyotypic heterogeneity, affected specific locus mutation rates, we utilized the heterozygous thymidine kinase (tk) locus as a genetic marker. Four x-ray induced HPRT - mutants with extensive karyotypic heterogeneity, exhibited mutation rates at tk ranging from 5 to 8 fold higher than the parental TK6 cells. Further analysis, using fractionated low dose radiation exposure, is currently in progress

Simulation of temperature effect on microalgae culture in a tubular photo bioreactor for local solar irradiance

Science.gov (United States)

Shahriar, M.; Deb, Ujjwal Kumar; Rahman, Kazi Afzalur

2017-06-01

Microalgae based biofuel is now an emerging source of renewable energy alternative to the fossil fuel. This paper aims to present computational model of microalgae culture taking effect of solar irradiance and corresponding temperature in a photo bioreactor (PBR). As microalgae is a photosynthetic microorganism, so irradiance of sunlight is one of the important limiting factors for the proper growth of microalgae cells as temperature is associated with it. We consider the transient behaviour of temperature inside the photo bioreactor for a microalgae culture. The optimum range of temperature for outdoor cultivation of microalgae is about 16-35°c and out of this range the cell growth inhibits. Many correlations have already been established to investigate the heat transfer phenomena inside a tubular PBR. However, none of them are validated yet numerically by using a user defined function in a simulated model. A horizontal tubular PBR length 20.5m with radius 0.05m has taken account to investigate the temperature effect for the growth of microalgae cell. As the solar irradiance varies at any geographic latitude for a year so an empirical relation is established between local solar irradiance and temperature to simulate the effect. From our simulation, we observed that the growth of microalgae has a significant effect of temperature and the solar irradiance of our locality is suitable for the culture of microalgae.

A comparative study of total body irradiation as a method of inducing granulocyte depletion in mice

International Nuclear Information System (INIS)

Bogman, M.J.J.T.; Cornelissen, I.M.H.A.; Berden, J.H.M.; Jong, J. de; Koene, R.A.P.

1984-01-01

Since conventional methods of inducing depletion of polymorphonuclear granulocytes (PMNs) in mice, such as treatment with cytostatic drugs and anti-PMN sera, proved to be insufficient to induce a stable PMN depletion for several days, and were accompanied by considerable toxic side effects, we induced neutrophil depletion in mice by total body irradiation (TBI) in a single dose of 6.0 Gy (600 rads.) at a dose rate of 0.20 Gy/min. This treatment reduced the number of PMNs in the peripheral circulation to values below 150/μl from day 3-10 after irradiation. The number of lymphocytes fell simultaneously. Platelet counts remained above 60% of normal values during the first 7 days after irradiation. Complement levels were not significantly affected by TBI. The results show that TBI of 6.0 Gy induces pronounced and stable PMN depletion in mice for at least 7 days. Furthermore, under an aseptic regimen the mice can be kept in good condition and losses are less than 5%. (Auth.)

Ionizing irradiation induces apoptotic damage of salivary gland acinar cells via NADPH oxidase 1-dependent superoxide generation

International Nuclear Information System (INIS)

Tateishi, Yoshihisa; Sasabe, Eri; Ueta, Eisaku; Yamamoto, Tetsuya

2008-01-01

Reactive oxygen species (ROS) have important roles in various physiological processes. Recently, several novel homologues of the phagocytic NADPH oxidase have been discovered and this protein family is now designated as the Nox family. We investigated the involvement of Nox family proteins in ionizing irradiation-induced ROS generation and impairment in immortalized salivary gland acinar cells (NS-SV-AC), which are radiosensitive, and immortalized ductal cells (NS-SV-DC), which are radioresistant. Nox1-mRNA was upregulated by γ-ray irradiation in NS-SV-AC, and the ROS level in NS-SV-AC was increased to approximately threefold of the control level after 10 Gy irradiation. The increase of ROS level in NS-SV-AC was suppressed by Nox1-siRNA-transfection. In parallel with the suppression of ROS generation and Nox1-mRNA expression by Nox1-siRNA, ionizing irradiation-induced apoptosis was strongly decreased in Nox1-siRNA-transfected NS-SV-AC. There were no large differences in total SOD or catalase activities between NS-SV-AC and NS-SV-DC although the post-irradiation ROS level in NS-SV-AC was higher than that in NS-SV-DC. In conclusion, these results indicate that Nox1 plays a crucial role in irradiation-induced ROS generation and ROS-associated impairment of salivary gland cells and that Nox1 gene may be targeted for preservation of the salivary gland function from radiation-induced impairment

Irradiation-induced permeability in pyrocarbon coatings. Final report of work conducted under PWS FD-12

International Nuclear Information System (INIS)

Kania, M.J.; Thiele, B.A.; Homan, F.J.

1982-10-01

Two US irradiation experiments were planned to provide information to supplement data from the German program on irradiation-induced permeability in pyrocarbon coatings. Hopefully, the data from both programs could be combined to define the onset of neutron-induced permeability in a variety of Biso coatings produced with different process variables (coating temperature, coating gases, and coating rates). The effort was not successful. None of the preirradiation characterization procedures were able to adequately predict irradiation performance. A large amount of within-batch scatter was observed in the fission gas and cesium release data along with significant within-batch variation in coating properties. Additional preirradiation characterization might result in a procedure that could successfully predict irradiation performance, but little can be done about the within-batch variation in coating properties. This variation is probably the result of random movement of particles within the coating furnace during pyrocarbon deposition. 19 figures, 4 tables

Simvastatin Ameliorates Radiation Enteropathy Development After Localized, Fractionated Irradiation by a Protein C-Independent Mechanism

International Nuclear Information System (INIS)

Wang Junru; Boerma, Marjan; Fu Qiang; Kulkarni, Ashwini; Fink, Louis M.; Hauer-Jensen, Martin

2007-01-01

Purpose: Microvascular injury plays a key role in normal tissue radiation responses. Statins, in addition to their lipid-lowering effects, have vasculoprotective properties that may counteract some effects of radiation on normal tissues. We examined whether administration of simvastatin ameliorates intestinal radiation injury, and whether the effect depends on protein C activation. Methods and Materials: Rats received localized, fractionated small bowel irradiation. The animals were fed either regular chow or chow containing simvastatin from 2 weeks before irradiation until termination of the experiment. Groups of rats were euthanized at 2 weeks and 26 weeks for assessment of early and delayed radiation injury by quantitative histology, morphometry, and quantitative immunohistochemistry. Dependency on protein C activation was examined in thrombomodulin (TM) mutant mice with deficient ability to activate protein C. Results: Simvastatin administration was associated with lower radiation injury scores (p < 0.0001), improved mucosal preservation (p = 0.0009), and reduced thickening of the intestinal wall and subserosa (p = 0.008 and p = 0.004), neutrophil infiltration (p = 0.04), and accumulation of collagen I (p = 0.0003). The effect of simvastatin was consistently more pronounced for delayed than for early injury. Surprisingly, simvastatin reduced intestinal radiation injury in TM mutant mice, indicating that the enteroprotective effect of simvastatin after localized irradiation is unrelated to protein C activation. Conclusions: Simvastatin ameliorates the intestinal radiation response. The radioprotective effect of simvastatin after localized small bowel irradiation does not appear to be related to protein C activation. Statins should undergo clinical testing as a strategy to minimize side effects of radiation on the intestine and other normal tissues

Possibilities of the reduction of a dose of metronidazole during irradiation of tumor with subsequent induced hyperglycemia

International Nuclear Information System (INIS)

Vinskaya, N.P.; Voloshina, E.A.; Kozin, S.V.

1989-01-01

The therapeutic efficacy of a scheme of polyradiomodification with metronidazole (MZ) administration was investigated in experiments on mice with Ehrlich carcinoma before local irradiation of tumors and with subsequent induced hyperglycemia (IH) depending on a MZ dose. For equally effective potentiation of the effect of radiation on a tumor during a combined use of MZ and postradiation IH a 4-fold lower dose of the drug was required as combined to MZ used alone. The combined effect of the modifiers was superadditive. The use of IH in this scheme not only potentiated skin radiation reactions on a tumor growth zone but also slighly weakened their expression

Fast neutron irradiation for locally advanced pancreatic cancer

International Nuclear Information System (INIS)

Smith, F.P.; Schein, P.S.; MacDonald, J.S.; Woolley, P.V.; Ornitz, R.; Rogers, C.

1981-01-01

Nineteen patients with locally advanced pancreatic cancer and one patient with islet cell cancer were treated with 1700-1500 neutron rad alone or in combination with 5-fluorouracil to exploit the theoretic advantages of higher linear energy of transfer, and lower oxygen enhancement ratio of neutrons. Only 5 of 14 (36%) obtained partial tumor regression. The median survival for all patients with pancreatic cancer was 6 months, which is less than that reported with 5-fluorouracil and conventional photon irradiation. Gastrointestinal toxicity was considerable; hemorhagic gastritis in five patients, colitis in two and esophagitis in one. One patient developed radiation myelitis. We therefore, caution any enthusiasm for this modality of therapy until clear evidence of a therapeutic advantage over photon therapy is demonstrated in controlled clinical trials

Fast neutron irradiation for locally advanced pancreatic cancer

Energy Technology Data Exchange (ETDEWEB)

Smith, F.P. (Georgetown Univ. Medical Center, Washington, DC); Schein, P.S.; MacDonald, J.S.; Woolley, P.V.; Ornitz, R.; Rogers, C.

1981-11-01

Nineteen patients with locally advanced pancreatic cancer and one patient with islet cell cancer were treated with 1700-1500 neutron rad alone or in combination with 5-fluorouracil to exploit the theoretic advantages of higher linear energy of transfer, and lower oxygen enhancement ratio of neutrons. Only 5 of 14 (36%) obtained partial tumor regression. The median survival for all patients with pancreatic cancer was 6 months, which is less than that reported with 5-fluorouracil and conventional photon irradiation. Gastrointestinal toxicity was considerable; hemorhagic gastritis in five patients, colitis in two and esophagitis in one. One patient developed radiation myelitis. We therefore, caution any enthusiasm for this modality of therapy until clear evidence of a therapeutic advantage over photon therapy is demonstrated in controlled clinical trials.

The effect of X-irradiation on the fertility and on the induction of meiotic chromosome rearrangements in mice and their first generation

International Nuclear Information System (INIS)

Savkovic, N.; Pecevski, J.; Maric, N.; Radivojevic, D.

1980-01-01

The effect of whole-body or local irradiation with X-rays at a dose of 600 R on the induction of chromosomal translocations in the diakinesis metaphase I of the meiosis in treated and F 1 males has been examined along with their fertility. Our results show the high percentage of mortality in whole-body irradiated mice. The percentage of the fertility was 25% in whole-body, and 93.7% in locally irradiated males. The testis weight was also reduced. The percentage of chromosomal translocations in diakinesis, metaphase I, of the meiosis was higher after whole-body irradiation than after local irradiation. In F 1 males both types of irradiation induced chromosomal translocations. (orig.) [de

Increased expressions of MMP-2 and MMP-9 in lung following 12 Gy local irradiation

International Nuclear Information System (INIS)

Yang Kunyu; Liu Li; Zhang Tao; Wu Gang; Hu Yu; Ruebe, C.; Ruebe, C.

2006-01-01

Objective: To measure expressions of metalloproteinases and tissue inhibitors of metalloproteinases in the lung following thoracic irradiation of 12 Gy, and explore its possible role in the development of radiation-induced lung damage. Methods: C57BL/6J mice at age of 8 weeks were thoracically irradiated with 12 Gy X-rays (10 MV, 2.4 Gy/min, single exposure), and the control mice were sham-irradiated. The mice were sacrificed at 4 or 8 weeks after thoracic irradiation by decapitation. Lung tissues samples were collected. Expressions of MMP-2, MMP-9, MMP-3, MMP-13, TIMP-1, TIMP-2, and TIMP-3 in lung samples were measured. Results: There was no significant difference in expressions of MMP-3, MMP-13, TIMP-1 TIMP-2, and TIMP-3 in the lung between the two groups at 4 and 8 weeks after thoracic irradiation (or sham-irradiation). However, the expressions of MMP-2 were enhanced by 1.7 and 1.9 folds, and MMP-9 by 2.7 and 2.6 folds at 4 and 8 weeks after thoracic irradiation, respectively. Conclusion: Enhanced expressions of MMP-2 and MMP-9 in the lung were involved in the development of acute lung injury after thoracic irradiation, leading to a disruption of the structure and fibrosis. (authors)

Inhibition of IL-1 activity induced with allogeneic transfusion of UV-irradiated blood

International Nuclear Information System (INIS)

Horvat, B.; Poljak-Blazi, M.; Hadija, M.

1991-01-01

Treatment with UV-irradiated donor-specific blood transfusion is known to induce specific unresponsiveness in recipient animals and prolong allograft survival. Mixed lymphocyte response in transfused mice was decreased towards spleen cells of the blood donor strain, but was not altered to third-party cells. Sera from treated mice showed significantly lower interleukin-1 (IL-1) activity, which was increased with higher dilutions of sera, indicating the presence of IL-1 inhibitor. Furthermore, sera decreased rIL-1-induced cell proliferation in dose-dependent manner, while the response to rIL-2 neither depended on the concentration of sera, nor differed between non-treated controls and treated mice. These results indicate that UV-irradiated allogeneic blood transfusion could induce an inhibitor, specifically directed to IL-1 activity, which may be involved in the generation of immunological unresponsiveness in treated animals. (author)

Irradiation-induced growth of zircaloy and its effects on the mechanical design of fuel assemblies

International Nuclear Information System (INIS)

Yao Pu

1991-01-01

Zircaloy growth could be induced due to irradiation. The ammount of growth is described as a function of texture, irradiation temperature, fast neutron fluence and the reduction of cold work, and it should be given great attention in the mechanical design of fuel assemblies

Protection from radiation induced changes in liver and serum transaminase of whole body gamma irradiated rats

International Nuclear Information System (INIS)

Elkashef, H.S.; Roushdy, H.M.; Saada, H.N.; Abdelsamie, M.

1986-01-01

Whole body gamma irradiation of rats with a dose of 5.5 Gy induced significant changes in the activity of liver and serum transaminase. The results indicated that this radiation dose caused a significant increase in the activity of serum Got and GPT on the third and seventh days after irradiation. This was followed by significant decreases on the fourteenth post-irradiation day. The activity of Got returned to is control activity, while the activity of GPT was significantly above the control on the twenty ones post-irradiation day. The activity of Got, in the liver of irradiated rats was elevated during the post-irradiation days, but on the twenty one day activity was about the normal value. The activity of liver GPT firstly decreased and then increased very much but attained the control level on the fourteenth after irradiation. The intraperitoneal injection of testosterone-vitamin E mixture 10 days before whole body gamma irradiation caused complete recovery for the activity of liver and serum Got. No indication of remarkable recovery in the case of GPT activity was recorded either in liver or in serum of irradiated rats. The applied mixture could protect against radiation induced changes in Got activity of liver and serum but could not protect or ameliorate the changes which occurred in the activity of GPT of the two tissues. 2 tab

Radiation induced muscositis as space flight risk. Model studies on X-ray and heavy ion irradiated typical oral mucosa models; Strahlungsinduzierte Mukositis als Risiko der Raumfahrt. Modelluntersuchungen an Roentgen- und Schwerionen-bestrahlten organotypischen Mundschleimhaut-Modellen

Energy Technology Data Exchange (ETDEWEB)

Tschachojan, Viktoria

2014-07-29

Humans in exomagnetospheric space are exposed to highly energetic heavy ion radiation which can be hardly shielded. Since radiation-induced mucositis constitutes a severe complication of heavy ion radiotherapy, it would also implicate a serious medical safety risk for the crew members during prolonged space flights such as missions to Moon or Mars. For assessment of risk developing radiation-induced mucositis, three-dimensional organotypic cultures of immortalized human keratinocytes and fibroblasts were irradiated with a {sup 12}C particle beam at high energies or X-Rays. Immunofluorescence stainings were done from cryosections and radiation induced release of cytokines and chemokines was quantified by ELISA from culture supernatants. The major focuses of this study were on 4, 8, 24 and 48 hours after irradiation. The conducted analyses of our mucosa model showed many structural similarities with the native oral mucosa and authentic immunological responses to radiation exposure. Quantification of the DNA damage in irradiated mucosa models revealed about twice as many DSB after heavy-ion irradiation compared to X-rays at definite doses and time points, suggesting a higher gene toxicity of heavy ions. Nuclear factor κB activation was observed after treatment with X-rays or {sup 12}C particles. An activation of NF κB p65 in irradiated samples could not be detected. ELISA analyses showed significantly higher interleukin 6 and interleukin 8 levels after irradiation with X-rays and {sup 12}C particles compared to non-irradiated controls. However, only X-rays induced significantly higher levels of interleukin 1β. Analyses of TNF-α and IFN-γ showed no radiation-induced effects. Further analyses revealed a radiation-induced reduction in proliferation and loss of compactness in irradiated oral mucosa model, which would lead to local lesions in vivo. In this study we revealed that several pro-inflammatory markers and structural changes are induced by X-rays and heavy

Induction of early long-range epigenetic changes by α-irradiation in arabidopsis thaliana plants

International Nuclear Information System (INIS)

Xu Shuyan; Li Fanghua; Wang Ting; Bian Po; Wu Yuejin

2011-01-01

Along the way, the mutagenic mechanism of low-energy ions irradiation is a debatable issue. Recently, the existence of radiation induced long-range (mutagenic) effects in vivo in plants has been performed in a series of studies of our group, which account for the mutagenesis of low-energy ions irradiation in a new perspective. However, numerous distinct biology phenomena remain to be addressed, which bear obvious characteristics to epigenetic.In the present study, using the expression of methylation-related AtDML3 gene and methylation level of specific gene segments as end points, the methylation of cytosine, the most important feature of epigenetic,was investigated. It was shown that, in A. thaliana, root-localized α-irradiation could induce epigenetic changes in aerial parts which avoided the direct irradiation. The radiation induced long-range epigenetic changes were confirmed in this study, which supplied innovative ideas for the further investigation of the mutagenetic mechanism of low-energy ions irradiation. (authors)

Influence of catechins on bystander responses in CHO cells induced by alpha-particle irradiation

Energy Technology Data Exchange (ETDEWEB)

Law, Y.L.; Wong, T.P.W. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Yu, K.N. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong)], E-mail: peter.yu@cityu.edu.hk

2010-04-15

In this work, we studied alpha-particle induced and medium-mediated bystander effects in Chinese hamster ovary (CHO) cells through micronucleus (MN) assay. We showed that signal transduction from irradiated cells to bystander cells occur within a short time after irradiation. We then studied the effects of ROS (reactive oxygen species)-scavenging catechins in the medium before irradiation. We observed decreases in the percentage of bystander cells with MN formation and thus proved the protection effect of catechins on bystander cells from radiation.

Transmission electron microscope study of neutron irradiation-induced defects in silicon

International Nuclear Information System (INIS)

Oshima, Ryuichiro; Kawano, Tetsuya; Fujimoto, Ryoji

1994-01-01

Commercial Czochralski-grown silicon (Cz-Si) and float-zone silicon (Fz-Si) wafers were irradiated with fission neutrons at various fluences from 10 19 to 10 22 n/cm 2 at temperatures ranging from 473 K to 1043 K. The irradiation induced defect structures were examined by transmission electron microscopy and ultra high voltage electron microscopy, which were compared with Marlowe code computer simulation results. It was concluded that the vacancy-type damage structure formed at 473 K were initiated from collapse of vacancy-rich regions of cascades, while interstitial type defect clusters formed by irradiation above 673 K were associated with interstitial oxygen atoms and free interstitials which diffused out of the cascades. Complex defect structures were identified to consist of {113} and {111} planar faults by the parallel beam illumination diffraction analysis. (author)

Low-energy electron irradiation induced top-surface nanocrystallization of amorphous carbon film

Science.gov (United States)

Chen, Cheng; Fan, Xue; Diao, Dongfeng

2016-10-01

We report a low-energy electron irradiation method to nanocrystallize the top-surface of amorphous carbon film in electron cyclotron resonance plasma system. The nanostructure evolution of the carbon film as a function of electron irradiation density and time was examined by transmission electron microscope (TEM) and Raman spectroscopy. The results showed that the electron irradiation gave rise to the formation of sp2 nanocrystallites in the film top-surface within 4 nm thickness. The formation of sp2 nanocrystallite was ascribed to the inelastic electron scattering in the top-surface of carbon film. The frictional property of low-energy electron irradiated film was measured by a pin-on-disk tribometer. The sp2 nanocrystallized top-surface induced a lower friction coefficient than that of the original pure amorphous film. This method enables a convenient nanocrystallization of amorphous surface.

Effect of irradiation on total chemical profiles of ten selected local herbs

International Nuclear Information System (INIS)

Salmah Moosa; Maizatul Akmam Mohd Nasir

2010-01-01

As utilisation of medicinal herbs in food and bio industry increases, mass production and the supply of high quality herbs are required. Restriction on the use of fumigants and preservatives on herbs demands safe hygienic technologies such as irradiation. The stability of the active components of ten local herbs after irradiation was studied. The herbs selected were Hempedu Bumi, Mas Cotek, Tongkat Ali, Kacip Fatimah, Misai Kucing, Dukung Anak, Jarum Tujuh Bilah, Kesom, Pegaga and Sambung Nyawa. The herbs were dried, powdered and irradiated at different doses of gamma radiation (0, 1, 3, 5, 10, 15 and 25 kGy) at room temperature prior to extraction. The herbs were then extracted either in methanol or chloroform and freeze dried. About 10.0 mg of each extract (in triplicates) were weighed into an Eppendorf vial and solubilised in 700 μl CD 3 OD using sonication in an ultrasound bath to obtain a clear solution. This solution was then transferred to a NMR vial and a 1H-NMR spectrum was acquired according to standard Total Quality Profile (TQP) protocol. The results of the statistical analysis showed clearly that all irradiated plant samples did not exhibit any significant pattern of differences. Using SIMCA analysis, we found that there is no statistical basis for separation of control, 1, 5, 10, 15 and 25 kGy irradiated samples on a 95 % confidence limit. TQP analysis for the ten selected herbal plant shows that irradiation up to 25 kGy did not cause significant changes to the total chemical profiles and thus the integrity of the herbal material in the analysed plants. (author)

Kinetics of radiation-induced structural alterations in electron-irradiated polymer-based composites

International Nuclear Information System (INIS)

Zaikin, Yu.A.; Potanin, A.S.; Koztaeva, U.P.

2002-01-01

Complete text of publication follows. In our previous studies measurements of internal friction temperature dependence were used for characterization of thermally activated and radiation-induced structural evolution in different types of polymer-based composites. This paper supplements these measurements with kinetic studies of internal friction (IF) parameters and EPR signals in a glass-cloth epoxy-filled laminate ST-ETF after electron irradiation up to doses of 1-10 MGy. Experiment have shown that the lifetime of free radicals in this composite considerably exceeds the characteristic time of molecular structural rearrangement due to scission and cross-linking after irradiation, as determined from IF measurements. This result is explained by slow proceeding of sterically hindered disproportionation reactions that stabilize the end groups of the macro-chain disrupt during irradiation and finally fix the act of scission. A mathematical model is formulated for description of structural evolution and alterations of IF parameters in polymer-based composites during and after electron irradiation. The description is based on the track model of radiation damage in polymers and phenomenological theory of radiation-induced structural transformations. General description does not give details of radiation-chemical conversion in different structural components of composites but indicates the direction of their structural evolution. In the model considered a composite material was divided into three parts (binder, filler, and a boundary layer). It was supposed that after primary distribution of radiation energy radiation-chemical conversion proceeds independently in each of these regions. It was also suggested that all the radical reactions were of the second order. On the example of glass-cloth laminate ST-ETF it is shown that this model allows to describe alterations in composite structural characteristics during irradiation and in the course of their self-organization after

Detection of radiation-induced hydrocarbons in baked sponge cake prepared with irradiated liquid egg

International Nuclear Information System (INIS)

Schulzki, G.; Spiegelberg, A.; Boegl, K.W.; Schreiber, G.A.

1995-01-01

For identification of irradiated food, radiation-induced volatile hydrocarbons (HC) are determined by gas chromatography in the non-polar fraction of fat. However, in complex food matrices the detection is often disturbed by fat-associated compounds. On-line coupling of high performance liquid chromatography (LC) and gas chromatography (GC) is very efficient to remove such compounds from the HC fraction. The high sensitivity of this fast and efficient technique is demonstrated by the example of detection of radiation-induced HC in fat isolated from baked sponge cake which had been prepared with irradiated liquid egg. (Author)

A molecular and genetic approach to understanding the mechanisms by which fractionated X-irradiation induces leukemia in mice

International Nuclear Information System (INIS)

Meruelo, D.; Rossomando, A.

1986-01-01

The authors laboratory's approach to try to shed light on the question of a viral etiology for radiation-induced leukemia has focused on defining, localizing and understanding the mode of action of genes involved in susceptibility to fractionated x-irradiation-(FXI) induced disease. These studies have indicated that multiple genes control the process of leukemogenesis. Not every mouse strain which shows some susceptibility to FXI-induced leukemia carries the susceptible gene at each of the multiple loci involved in the disease process. It is plausible to conclude that more than one mechanism of leukemogenesis can be triggered by FXI. Studies have focused on the mode of action of one such locus Ril-1. Several reagents have been developed to help clone and characterize this locus. Currently chromosomal ''walking'' and ''hopping'' techniques are being used in conjunction with an RFLP molecular probe which is adjacent to Ril-1. In addition a cDNA library has been prepared from a radiation-induced thymoma and substraction hybridization analysis is being used in the search for Ril-1. (author)

Inhibition of DNA repair by whole body irradiation induced nitric oxide leads to higher radiation sensitivity in lymphocytes

International Nuclear Information System (INIS)

Sharma, Deepak; Santosh Kumar, S.; Raghu, Rashmi; Maurya, D.K.; Sainis, K.B.

2007-01-01

Full text: It is well accepted that the sensitivity of mammalian cells is better following whole body irradiation (WBI) as compared to that following in vitro irradiation. However, the underlying mechanisms are not well understood. Following WBI, the lipid peroxidation and cell death were significantly higher in lymphocytes as compared to that in vitro irradiated lymphocytes. Further, WBI treatment of tumor bearing mice resulted in a significantly higher inhibition of EL-4 cell proliferation as compared to in vitro irradiation of EL-4 cells. The DNA repair was significantly slower in lymphocytes obtained from WBI treated mice as compared to that in the cells exposed to same dose of radiation in vitro. Generation of nitric oxide following irradiation and also its role in inhibition of DNA repair have been reported, hence, its levels were estimated under both WBI and in vitro irradiation conditions. Nitric oxide levels were significantly elevated in the plasma of WBI treated mice but not in the supernatant of in vitro irradiated cells. Addition of sodium nitroprusside (SNP), a nitric oxide donor to in vitro irradiated cells inhibited the repair of DNA damage and sensitized cells to undergo cell death. It also enhanced the radiation-induced functional impairment of lymphocytes as evinced from suppression of mitogen-induced IL-2, IFN-γ and bcl-2 mRNA expression. Administration of N G -nitro-L-arginine-methyl-ester(L-NAME), a nitric oxide synthase inhibitor, to mice significantly protected lymphocytes against WBI-induced DNA damage and inhibited in vivo radiation-induced production of nitric oxide. Our results indicated that nitric oxide plays a role in the higher radiosensitivity of lymphocytes in vivo by inhibiting repair of DNA damage

Search for the lowest irradiation dose from literatures on radiation-induced cancer in gastrointestinal tract

Energy Technology Data Exchange (ETDEWEB)

Yoshizawa, Y; Kusama, T [Tokyo Univ. (Japan). Faculty of Medicine

1976-05-01

A survey of past case reports about radiation-induced cancer in the gastrointestinal tract was carried out with the main object of finding the lowest irradiation dose. Search of the literature published since 1923 revealed 80 cases of radiation-induced large intestine cancer and one case of stomach cancer. The cases of radiation-induced cancer in the large intestine had received radiation for the treatment of non-malignant conditions, fibroma, ovarial cyste, myoma, endometritis and duodenal ulcer. The lowest irradiation dose was estimated at 460 rads. Adenocarcinoma was the histopathological finding in all cases of radiation-induced cancer in the caecum, colon and rectum, and squamous cell carcinoma in the cases of anal cancer. The latent period ranged from 1 to 31 years, with the average of 13.6 years. There were some reports of statistical studies of radiation-induced stomach cancer. Three groups were the subjects of these studies. The first group was composed of atomic bomb survivors, the second of patients who had undergone radiation treatment for ankylosing spondilitis, and the third of duodenal ulcer patients subjected to radiation treatment for the purpose of suppressing gastric acid secretion. These statistical studies showed no significant increase of the incidence of stomach cancer in the irradiated groups.

Search for the lowest irradiation dose from literatures on radiation-induced cancer in gastrointestinal tract

International Nuclear Information System (INIS)

Yoshizawa, Yasuo; Kusama, Tomoko

1976-01-01

A survey of past case reports about radiation-induced cancer in the gastrointestinal tract was carried out with the main object of finding the lowest irradiation dose. Search of the literature published since 1923 revealed 80 cases of radiation-induced large intestine cancer and one case of stomach cancer. The cases of radiation-induced cancer in the large intestine had received radiation for the treatment of non-malignant conditions, fibroma, ovarial cyste, myoma, endometritis and duodenal ulcer. The lowest irradiation dose was estimated at 460 rads. Adenocarcinoma was the histopathological finding in all cases of radiation-induced cancer in the caecum, colon and rectum, and squamous cell carcinoma in the cases of anal cancer. The latent period ranged from 1 to 31 years, with the average of 13.6 years. There were some reports of statistical studies of radiation-induced stomach cancer. Three groups were the subjects of these studies. The first group was composed of atomic bomb survivors, the second of patients who had undergone radiation treatment for ankylosing spondilitis, and the third of duodenal ulcer patients subjected to radiation treatment for the purpose of suppressing gastric acid secretion. These statistical studies showed no significant increase of the incidence of stomach cancer in the irradiated groups. (auth.)

Irradiation induced tensile property change of SA 508 Cl.3 reactor pressure vessel steels

International Nuclear Information System (INIS)

Chi, Se-Hwan; Hong, Jun-Hwa; Kuk, Il-Hiun

1998-01-01

Irradiation induced tensile property change of four kinds of reactor pressure vessel steels manufactured by different steel refining process was compared based on the differences in the unirradiated and irradiated microstructure. Microvickers hardness, indentation, and miniature tensile specimen tests were conducted for mechanical property measurement and optical microscope (OM) and transmission electron microscope (TEM) were used for microstructural characterization. Specimens were 2 irradiated to a neutron fluence of 2.7x10 19 n/cm 2 (E ≥ 1 MeV) at 288 deg. C. Investigation on the unirradiated microstructures showed largely a same microstructure in that tempered acicular bainite and ferrite with bainitic phase prevailing in the unirradiated condition. Band-shaped segregations were also clearly observed except a kind of materials. A large difference in the unirradiated microstructure appeared in the grain size and carbide microstructure. Of carbide microstructures, noticeable differences were observed in the size and distribution of cementite, and bainitic lath microstructures. No noticeable changes were observed in the optical and thin film TEM microstructures after irradiation. Complicated microstructural. state of heat treated bainitic low alloy microstructure prevents easy quantification of microstructural changes due to irradiation. Apparent differences, however, were observed in the results of mechanical testing. Results of tensile testing and hardness measurement show that a steel refined by vacuum carbon deoxidation(VCD) method exhibits the highest radiation hardening behavior. Some of mechanical testing results on irradiated materials were possible to understand based on the initial microstructure, but further investigations using a wide array of sophisticated tools (for example, SANS, APFIM) are required to understand and characterize irradiation induced defects that are responsible for irradiation hardening behavior but are not revealed by

Ionizing radiation-induced MEK and Erk activation does not enhance survival of irradiated human squamous carcinoma cells

International Nuclear Information System (INIS)

Bonner, James A.; Vroman, Benjamin T.; Christianson, Teresa J.H.; Karnitz, Larry M.

1998-01-01

Purpose: Ionizing radiation (IR) triggers several intracellular signaling cascades that have commonly been regarded as mitogenic, including the Raf-MEK-Erk kinase cascade. In addition to promoting proliferation, activated MEK and Erk may also prevent cell death induced by cytotoxic stimuli. Because Raf, MEK, and Erk are activated by IR in some tumor cell lines, this suggests that IR-induced activation of the kinase cascade may enhance the survival of irradiated cells. Methods and Materials: IR-induced activation of MEK and Erk was assessed in irradiated UM-SCC-6 cells, a human squamous carcinoma cell line. Activation of MEK and Erk was blocked with the pharmacological inhibitor of MEK activation, PD098059. Clonogenic survival was assessed in irradiated UM-SCC-6 cells that were pretreated with nothing or with the MEK inhibitor. Results: In UM-SCC-6 cells, IR doses as low as 2 Gy rapidly activated MEK and Erk. Pretreatment of the cells with the pharmacological inhibitor of MEK activation, PD098059, effectively blocked IR-induced activation of MEK and Erk. However, inhibition of the kinase cascade did not affect the clonogenic survival of irradiated cells in either early or delayed-plating experiments. Conclusion: Taken together, these results suggest that although MEK and Erk are rapidly activated by IR treatment, these protein kinases do not affect the clonogenic survival of irradiated UM-SCC6 cells

Evaluation of induced radioactivity in 10 MeV-Electron irradiated spices, (2); [beta]-ray counting

Energy Technology Data Exchange (ETDEWEB)

Katayama, Tadashi; Furuta, Masakazu; Shibata, Setsuko; Matsunami, Tadao; Ito, Norio; Mizohata, Akira; Toratani, Hirokazu (Osaka Prefectural Univ., Sakai (Japan). Research Inst. for Advanced Science and Technology); Takeda, Atsuhiko

1994-02-01

In order to check radioactivity of beta-emmitters produced by ([gamma], n) reactions which could occur at energies up to 10 MeV, black pepper, white pepper, red pepper, ginger and turmeric were irradiated with 10 MeV electron from a linear accelerator to a dose of 100 kGy. Beta-rays were counted using a 2[pi] gas flow counter and a liquid scintillation counter. Any induced radioactivity could not be detected in irradiated samples. When inorganic compounds containing the nuclides in the list were artificially added in the samples and were irradiated, the [beta]-activities were detected. From the amount of observed radioactivities of [beta]-emmitters produced in the compounds as photonuclear products, it is concluded that the induced radioactivity in natural samples by 10 MeV-electron irradiation were far smaller than natural radioactivity from [sup 40]K contained in the samples and, hence, its biological effects should be negligible. (author).

On the modeling of irradiation-induced homogeneous precipitation in proton-bombarded Ni-Si solid solutions

Science.gov (United States)

Lam, Nghi Q.; Janghorban, K.; Ardell, A. J.

1981-10-01

Irradiation-induced solute redistribution leading to precipitation of coherent γ' particles in undersaturated Ni-based solid solutions containing 6 and 8 at.% Si during 400-keV proton bombardment was modeled, based on the concept of solute segregation in concentrated alloys under spatially-dependent defect production conditions. The combined effects of (i) an extremely large difference between the defect production rates in the peak-damage and mid-range regions during irradiation and (ii) a preferential coupling between the interstitial and solute fluxes generate a net transient flux of Si atoms into the mid-range region, which is much larger than the solute flux out of this location. As a result, the Si concentration exceeds the solubility limit and homogeneous precipitation of the γ' phase occurs in this particular region of the irradiated samples. The spatial, compositional and temperature dependences of irradiation-induced homogeneous precipitation derived from the present theoretical calculations are in good qualitative agreement with experimental observations

Modifications induced by gamma irradiation to Makrofol polymer nuclear track detector

Directory of Open Access Journals (Sweden)

A. Tayel

2015-03-01

Full Text Available The aim of the present study was extended from obtaining information about the interaction of gamma rays with Makrofol DE 7-2 track detector to introduce the basis that can be used in concerning simple sensor for gamma irradiation and bio-engineering applications. Makrofol polymer samples were irradiated with 1.25 MeV 60Co gamma radiations at doses ranging from 20 to 1000 kG y. The modifications of irradiated samples so induced were analyzed using UV–vis spectrometry, photoluminescence spectroscopy, and the measurements of Vickers’ hardness. Moreover, the change in wettability of irradiated Makrofol was investigated by the contact angle determination of the distilled water. UV–vis spectroscopy shows a noticeable decrease in the energy band gap due to gamma irradiation. This decrease could be attributed to the appearance of a shift to UV spectra toward higher wavelength region after irradiation. Photoluminescence spectra reveal a remarkable change in the integrated photoluminescence intensity with increasing gamma doses, which may be resulted from some matrix disorder through the creation of some defected states in the irradiated polymer. The hardness was found to increase from 4.78 MPa for the unirradiated sample to 23.67 MPa for the highest gamma dose. The contact angle investigations show that the wettability of the modified samples increases with increasing the gamma doses. The result obtained from present investigation furnishes evidence that the gamma irradiations are a successful technique to modify the Makrofol DE 7-2 polymer properties to use it in suitable applications.

Blue light irradiation-induced oxidative stress in vivo via ROS generation in rat gingival tissue.

Science.gov (United States)

Yoshida, Ayaka; Shiotsu-Ogura, Yukako; Wada-Takahashi, Satoko; Takahashi, Shun-suke; Toyama, Toshizo; Yoshino, Fumihiko

2015-10-01

It has been reported that oxidative stress with reactive oxygen species (ROS) generation is induced by blue light irradiation to a living body. Only limited research has been reported in dental field on the dangers of blue light, mostly focusing on cytotoxicity associated with heat injury of dental pulp. We thus performed an in vivo study on oral tissue exposed to blue light. ROS generated upon blue light irradiation of flavin adenine dinucleotide were measured by electron spin resonance spectroscopy. After blue light irradiation, the palatal gingiva of Wistar rats were isolated. Collected samples were subjected to biochemical analysis of lipid peroxidation and glutathione. Singlet oxygen was generated by blue light irradiation, but was significantly quenched in an N-acetyl-L-cysteine (NAC) concentration-dependent manner. Blue light significantly accelerated oxidative stress and increased the oxidized glutathione levels in gingival tissue. These effects were also inhibited by NAC pre-administration. The results suggest that blue light irradiation at clinical levels of tooth bleaching treatment may enhance lipid peroxidation by the induction of oxidative stress and the consumption of a significant amount of intracellular glutathione. In addition, NAC might be an effective supplement for the protection of oral tissues against blue light irradiation-induced oxidative damage. Copyright © 2015 Elsevier B.V. All rights reserved.

Irradiation induced improvement in crystallinity of epitaxially grown Ag thin films on Si substrates

Energy Technology Data Exchange (ETDEWEB)

Takahiro, Katsumi; Nagata, Shinji; Yamaguchi, Sadae [Tohoku Univ., Sendai (Japan). Inst. for Materials Research

1997-03-01

We report the improvement in crystallinity of epitaxially grown Ag films on Si(100) substrates with ion irradiation. The irradiation of 0.5 MeV Si ions to 2x10{sup 16}/cm{sup 2} at 200degC, for example, reduces the channeling minimum yield from 60% to 6% at Ag surface. The improvement originates from the decrease of mosaic spread in the Ag thin film. In our experiments, ion energy, ion species and irradiation temperature have been varied. The better crystallinity is obtained as the higher concentration of defect is generated. The mechanism involved in the irradiation induced improvement is discussed. (author)

Green Tea attenuates some biochemical disorders induced by γ- irradiation in male rats

International Nuclear Information System (INIS)

Nada, A.S.; Amin, N.E.; Aziz, M.M.; Ain-Shoka, A.; Abdel-Latif, H.A.

2012-01-01

While radiation hazards, due to free radical generation, present an enormous challenge for biological and medical safety, green tea extract is a potent scavenger of a variety of free radicals. This study was conducted to evaluate the modulating efficacy of prolonged oral administration of green tea against gamma radiation-induced cellular damage in the liver and kidney in male rats using vitamin E as a reference drug. Green tea aqueous extract (300 mg/Kg body weighty) or vitamin E (40 mg/ Kg body weighty) were administered to male albino rats via gavages during 21 successive days before whole body exposure to gamma rays (6.5 Gy), from cesium-137 source, and during 7 days after irradiation. The animals were sacrificed the 7th day post-irradiation. The levels of cholesterol, triglyceride (TG), urea, and creatinine, as well as activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP) were significantly increased in sera of the irradiated rats. Moreover, radiation induced disturbances in liver and kidney content of calcium (Ca), magnesium (Mg) and manganese (Mn). Treatment with green tea extract and or vitamin E before and post irradiation were significantly ameliorated the levels of cholesterol, TG, creatinine, and urea, as well as the activities of AST, ALT, and ALP in serum. Also, green tea extract and or vitamin E achieved significant amelioration liver and kidney contents of Ca, Mg and Mn. In conclusion, green tea extract and or vitamin E show a radioprotective impact against ionizing-radiation-induced liver and kidney injury

In vivo evaluation of expression of TGFβ1 in the irradiated heart

International Nuclear Information System (INIS)

Affonso Junior, Renato Jose; Oshima, Celina Tizuko Fujiyama; Silva, Maria Regina Regis; Kimura, Edna Teruko; Egami, Mizue Imoto; Segreto, Roberto Araujo; Segreto, Helena Regina Comodo

2004-01-01

The objectives of this study were to assess the latent and active TGFβ1 localization in the heart, to evaluate whether or not radiation induces latent TGFβ1 activation, and to study the distribution of collagen fibers in the irradiated heart. Thirty-two C 57 BL mice were randomly assigned in two groups: GI (non irradiated animals) and GII (irradiated animals). The mice from G II received a single whole-body radiation dose of 7 Gy, using a 60 Co source at a dose rate of 0.97 Gy/min. The animals were sacrificed by cervical dislocation at 1, 14, 30 and 90 days after irradiation. The irradiated hearts showed: nuclear changes and muscle cells with decreased striations; significant increase in the collagen deposition 90 days after irradiation; latent TGFβ1 activation in the cardio myocytes and connective tissue cells after irradiation. Our results show the importance of TGFβ1 protein in the process of radiation-induced heart fibrosis and suggest that cardio myocytes and connective cells may play a role in this mechanism acting as cellular sources of active TGFβ1. (author)

Radiation retinopathy caused by low dose irradiation and antithyroid drug-induced systemic vasculitis

International Nuclear Information System (INIS)

Sonoda, Koh-hei; Ishibashi, Tatsuro

2005-01-01

We report on a patient with Graves' disease with radiation retinopathy caused by low-dose irradiation and antithyroid drug-induced antineutrophil cytoplasmic antibody (ANCA)-positive vasculitis. A 38-year-old woman with Graves' disease presented with bilateral blurred vision, micro-aneurysms, telangiectasia, and macular edema. The patient was examined by ophthalmoscopy and fluorescein angiography, and radiation retinopathy was diagnosed. The patient had been treated with low-dose irradiation for her Graves' ophthalmopathy a few years earlier. She also had ANCA-positive vasculitis induced by the antithyroid drug (propylthiouracil, PTU) that had been prescribed for her at that time. Because of multiple avascular areas on both retinas, she was treated by intensive retinal photocoagulation to control progressive retinopathy. The radiation doses used to treat Graves' disease ophthalmopathy are low. Nevertheless, there is still a risk of radiation retinopathy developing in patients with PTU-induced ANCA-positive vasculitis. (author)

Deuterium ion irradiation induced precipitation in Fe–Cr alloy: Characterization and effects on irradiation behavior

International Nuclear Information System (INIS)

Liu, P.P.; Yu, R.; Zhu, Y.M.; Zhao, M.Z.; Bai, J.W.; Wan, F.R.; Zhan, Q.

2015-01-01

Highlights: • A new phase precipitated in Fe–Cr alloy after deuterium ion irradiation at 773 K. • B2 structure was proposed for the Cr-rich new phase. • Strain fields around the precipitate have been measured by GPA. • The precipitate decrease growth rate of dislocation loop under electron irradiation. - Abstract: A new phase was found to precipitate in a Fe–Cr model alloy after 58 keV deuterium ion irradiation at 773 K. The nanoscale radiation-induced precipitate was studied systematically using high resolution transmission electron microscopy (HRTEM), image simulation and in-situ ultrahigh voltage transmission electron microscopy (HVEM). B2 structure is proposed for the new Cr-rich phase, which adopts a cube-on-cube orientation relationship with regard to the Fe matrix. Geometric phase analysis (GPA) was employed to measure the strain fields around the precipitate and this was used to explain its characteristic 1-dimensional elongation along the 〈1 0 0〉 Fe direction. The precipitate was stable under subsequent electron irradiation at different temperatures. We suggest that the precipitate with a high interface-to-volume ratio enhances the radiation resistance of the material. The reason for this is the presence of a large number of interfaces between the precipitate and the matrix, which may greatly reduce the concentration of point defects around the dislocation loops. This leads to a significant decrease in the growth rate

Adaptive response of spermatogenic cell apoptosis selectively induced by low dose X-ray irradiation in mice

International Nuclear Information System (INIS)

Liu Guangwei; Dong Lihua; Liu Yang; Lv Zhe; Liu Shuchun; Gong Shouliang

2003-01-01

Objective: The adaptive response of spermatogenic cell apoptosis induced by whole-body X-ray irradiation at low doses was studied in mice. Methods: Kunming male mice were irradiated with an inductive dose (D1:75 mGy) and/or a challenging dose (D2:1.0, 2.0 or 3.0 Gy). Different kinds of spermatogenic cells were separated using density gradient centrifugation and their apoptotic percentages were analysed using flow cytometry (FCM). Results: When the mice were irradiated with D1 6 h before irradiation with D2, the apoptotic percentages of the spermatogonia and spermatocytes declined rapidly as compared with those in the groups irradiated with D2 only, and those of spermatids and spermatozoa showed no significant changes. When the interval times between D1 and D2 was 3, 6, 12 or 24 h, the apoptotic percentages in spermatogonia and spermatocytes reduced early, significantly and continued for a longer duration after smaller D2(1.0 and 2.0 Gy) irradiation, while the apoptotic percentages did not change after larger D2(3.0 Gy) irradiation. Conclusion: The adaptive response of apoptosis in spermatogonia and spermatocytes could be selectively induced by low dose X-ray irradiation. The adaptive response could be closely related to the D2 dose and interval time between D1 and D2

Single Low-Dose Ionizing Radiation Induces Genotoxicity in Adult Zebrafish and its Non-Irradiated Progeny.

Science.gov (United States)

Lemos, J; Neuparth, T; Trigo, M; Costa, P; Vieira, D; Cunha, L; Ponte, F; Costa, P S; Metello, L F; Carvalho, A P

2017-02-01

This study investigated to what extent a single exposure to low doses of ionizing radiation can induce genotoxic damage in irradiated adult zebrafish (Danio rerio) and its non-irradiated F1 progeny. Four groups of adult zebrafish were irradiated with a single dose of X-rays at 0 (control), 100, 500 and 1000 mGy, respectively, and couples of each group were allowed to reproduce following irradiation. Blood of parental fish and whole-body offspring were analysed by the comet assay for detection of DNA damage. The level of DNA damage in irradiated parental fish increased in a radiation dose-dependent manner at day 1 post-irradiation, but returned to the control level thereafter. The level of DNA damage in the progeny was directly correlated with the parental irradiation dose. Results highlight the genotoxic risk of a single exposure to low-dose ionizing radiation in irradiated individuals and also in its non-irradiated progeny.

Analysis of decay of radicals induced in irradiated foods during long storage

International Nuclear Information System (INIS)

Kishita, Keigo; Kawamura, Shoei; Nakamura, Hideo; Ukai, Mitsuko; Kikuchi, Masahiro; Kobayashi, Yasuhiko

2013-01-01

By electron spin resonance (ESR) spectroscopy, we revealed free radicals in γ-ray irradiated foods ; black pepper, green coffee bean, cereal flour and ginseng. We also analyzed the decay behavior of radiation induced free radicals during long storage. The ESR spectrum of experimental irradiated foods consists of a sextet signal centered at g=2.0 and a singlet signal at the same g-value position and a singlet signal at g=4.0. The ESR spectrum of the cereal flour sample showed only singlet signal at g=2.0. The singlet signal at g=2.0 is originated from organic free radicals and its peak intensity showed the dependence of γ-ray radiation dose levels. But the signal intensity was decreased during storage. Only after 3 hours of radiation treatment the peak intensity was decreased fast and after that the intensity was decreased slowly. The analysis of radical decay process using the simulation methods based on the theory of reaction speed, the three decay behavior was showed. It is considered that at least three or more kinds of radicals were induced in irradiated foods and in decay during long time storage. (author)

Studies on γ-irradiation-induced-degradation of chloramphenicol in aqueous solution

International Nuclear Information System (INIS)

Xie Fang; Ha Yiming; Wang Feng; Zhou Hongjie

2008-01-01

The irradiation-induced degradation of chloramphenicol by γ-rays in aqueous solution was studied and the radiolytical products were determined. The relationship among degradation rate, absorbed dose and initial concentration have been explored by comparing the position of maximum absorption peaks of chloramphenicol be- fore and after irradiation using high performance liquid chromatography. The identification of radiolytical products has been conducted using liquid chromatography tandem mass spectrometry. It has been found that the relationship among C/C 0 , absorbed dose and initial concentration can be fit with index curve. After irradiation, more than 30 radiolytical products with stable absorption below 278nm could be determined. 8 major radiolytical products with [M-H] - 353, 337, 335(A), 335(B), 319, 289, 127, 166, which are detected in several different conditions, have been picked up. Their possible structures are deducted. (authors)

Effect of local UV irradiation of generative nuclei of Paramecium caudatum on sexual functions of the cells

International Nuclear Information System (INIS)

Skoblo, I.I.; Borkhsenius, O.N.

1979-01-01

The functions of micronucleus (MI) were studied in the period of the sexual process in Paramecium caudatum-infusoria the descendants of the cells, whose micronucleus was locally irradiated with UV rays at the dose of 3060 erg/mm 2 . It has been found that the descendants of the irradiated cells (the cells of UV clones) can be involved into the sexual process irrespoctive of the morphological type of their MI. Four out of forteen UV clones have changed the initial mating type for the opposite one. It is suggested that the change of the mating type is related to the changes of MI genome resulted from UV irradiation. The pathway of nuclear transformations in the course of sexual process was traced in cells of three UV clones. It has been found, that local UV irradiation of MI causes a number of deviations in the behaviour of MI derivatives in the metagamic part of the sexual process in the clones, whose MI have undergone substantial morphological changes. The exconjugants produced by crossing of UV clones with such changed MI and the normal test-clone were characterized by low viability

Intestinal metaplasia induced by x-irradiation in different strains of rats

International Nuclear Information System (INIS)

Watanabe, Hiromitsu; Naito, Masashi; Kawashima, Kengo; Ito, Akihiro

1985-01-01

Attempts were made to examine strain differences in the susceptibility of rats to intestinal metaplasia induced by X-irradiation. The gastric regions of 4 inbred male rats (SHR, F344, WKY, and LEW strains) in 5-week-old and 2 random bred male rats (SD, and WIS strains) were irradiated with a total dose of 20 Gy X-ray given in two equal fractions separated by three days. Upon sacrifice at 6 months after the last irradiation, the number of intestinal metaplastic crypts with positive reaction to alkaline phosphatase (ALP) appeared highest in the SHR and lowest in the WIS rats. Morphologically, the number of crypts with intestinal metaplasia in whole glandular stomachs of SHR, WIS, F344, and SD rats were higher than those in WKY and LEW rats. In the pyloric gland, it was highest in WIS rats, while in the fundic gland it was highest in SHR rats. The results show that the appearance and location of intestinal metaplasia by X-irradiation are greatly influenced by the strain of the rat. (author)

Irradiation-assisted stress corrosion cracking considerations at temperatures below 288 degree C

International Nuclear Information System (INIS)

Simonen, E.P.; Jones, R.H.; Bruemmer, S.M.

1995-03-01

Irradiation-assisted stress corrosion cracking (IASCC) occurs above a critical neutron fluence in light-water reactor (LWR) water environments at 288 C, but very little information exists to indicate susceptibility as temperatures are reduced. Potential low-temperature behavior is assessed based on the temperature dependencies of intergranular (IG) SCC in the absence of irradiation, radiation-induced segregation (RIS) at grain boundaries and micromechanical deformation mechanisms. IGSCC of sensitized SS in the absence of irradiation exhibits high growth rates at temperatures down to 200 C under conditions of anodic dissolution control, while analysis of hydrogen-induced cracking suggests a peak crack growth rate near 100 C. Hence from environmental considerations, IASCC susceptibility appears to remain likely as water temperatures are decreased. Irradiation experiments and model predictions indicate that RIS also persists to low temperatures. Chromium depletion may be significant at temperatures below 100C for irradiation doses greater than 10 displacements per atom (dpa). Macromechanical effects of irradiation on strength and ductility are not strongly dependent on temperature below 288 C. However, temperature does significantly affect radiation effects on SS microstructure and micromechanical deformation mechanisms. The critical conditions for material susceptibility to IASCC at low temperatures may be controlled by radiation-induced grain boundary microchemistry, strain localization due to irradiation microstructure and irradiation creep processes. 39 refs

Plasmatic and thermographic consequences of local acute irradiation; a qualitative and quantitative analysis in the pig

International Nuclear Information System (INIS)

Lefaix, J.L; Daburon, F.; Crechet, F.; Tricaud, Y.

1987-04-01

Acute phase reactant proteins associated with thermographic measurements and enzymatic activity assays in plasma were carried out on 39 pigs, following local exposure of the thigh to a collimated source of iridium 192 at doses ranging between 30 and 84 Gy (2 cm depth dose). The inflammatory response after irradiation, from day 1 to day 30 was accompanied by plasma protein changes associated with an elevation of local and general temperatures in irradiated animals. Degenerative processes in muscle led to an increase of plasmatic creatine kinase and lactate-dehydrogenase. Results were developed qualitatively (distribution pattern of proteins, thermographic measurements, enzymatic activities and clinical evolution of the lesions) and qualitatively (plasma level of creatine kinase versus applied radiation doses and pharmalogical treatments) [fr

Vasoconstriction Potency Induced by Aminoamide Local Anesthetics Correlates with Lipid Solubility

Directory of Open Access Journals (Sweden)

Hui-Jin Sung

2012-01-01

Full Text Available Aminoamide local anesthetics induce vasoconstriction in vivo and in vitro. The goals of this in vitro study were to investigate the potency of local anesthetic-induced vasoconstriction and to identify the physicochemical property (octanol/buffer partition coefficient, pKa, molecular weight, or potency of local anesthetics that determines their potency in inducing isolated rat aortic ring contraction. Cumulative concentration-response curves to local anesthetics (levobupivacaine, ropivacaine, lidocaine, and mepivacaine were obtained from isolated rat aorta. Regression analyses were performed to determine the relationship between the reported physicochemical properties of local anesthetics and the local anesthetic concentration that produced 50% (ED50 of the local anesthetic-induced maximum vasoconstriction. We determined the order of potency (ED50 of vasoconstriction among local anesthetics to be levobupivacaine > ropivacaine > lidocaine > mepivacaine. The relative importance of the independent variables that affect the vasoconstriction potency is octanol/buffer partition coefficient > potency > pKa > molecular weight. The ED50 in endothelium-denuded aorta negatively correlated with the octanol/buffer partition coefficient of local anesthetics (r2=0.9563; P<0.001. The potency of the vasoconstriction in the endothelium-denuded aorta induced by local anesthetics is determined primarily by lipid solubility and, in part, by other physicochemical properties including potency and pKa.

Fate mapping of the silkworm, Bombyx mori, using localized UV irradiation of the egg at fertilization

International Nuclear Information System (INIS)

Myohara, Maroko

1994-01-01

Bombyx eggs at the fertilization stage (0-2 hours after oviposition) were irradiated with a scanning UV-laser microbeam (355 nm) over an area of about 1% of the total egg surface. In spite of absence of nuclei or cells at the irradiated sites, larvae from treated eggs showed localized cuticle defects in the integument. The location and frequency of the defects within the cuticular pattern correlated closely to the site of irradiation both in the anteroposterior and the dorsoventral direction. Based on the correlation, presumptive regions for each larval segment were located and a fate map of the Bombyx egg was established. (author)

Irradiation-induced creep in metallic nanolaminates characterized by In situ TEM pillar nanocompression

Energy Technology Data Exchange (ETDEWEB)

Dillon, Shen J., E-mail: sdillon@illinois.edu [Department of Materials Science and Engineering, University of Illinois Urbana-Champagin, Urbana, IL 61801 (United States); Bufford, Daniel C. [Sandia National Laboratories, Albuquerque, NM 87185 (United States); Jawaharram, Gowtham S.; Liu, Xuying; Lear, Calvin [Department of Materials Science and Engineering, University of Illinois Urbana-Champagin, Urbana, IL 61801 (United States); Hattar, Khalid [Sandia National Laboratories, Albuquerque, NM 87185 (United States); Averback, Robert S. [Department of Materials Science and Engineering, University of Illinois Urbana-Champagin, Urbana, IL 61801 (United States)

2017-07-15

This work reports on irradiation-induced creep (IIC) measured on nanolaminate (Cu-W and Ni-Ag) and nanocrystalline alloys (Cu-W) at room temperature using a combination of heavy ion irradiation and nanopillar compression performed concurrently in situ in a transmission electron microscope. Appreciable IIC is observed in multilayers with 50 nm layer thicknesses at high stress, ≈½ the yield strength, but not in multilayers with only 5 nm layer thicknesses.

The genetic effects induced by an irradiation in low doses at Drosophila melanogaster

International Nuclear Information System (INIS)

Zajnullin, V.G.; Taskaev, A.I.; Moskalev, A.A.; Shaposhnikov, M.V.

2006-01-01

The review generalizes the results obtained in researches of genetic radiation effects for Drosophila melanogaster from contamination regions near the Chernobylsk NPP. The results of laboratory investigations of low dose irradiation effects on genotype variability and lifetime of Drosophila are presented too. It supposed that the main effect of low dose irradiation is caused by the induced genetic instability against the background of which the realization of different-directed radiobiological reactions is possible [ru

Effect and adaptive response of lymphocytes DNA induced by low dose irradiation

International Nuclear Information System (INIS)

Du Zeji; Su Liaoyuan; Tian Hailin

1994-09-01

Fluorometric analysis of DNA unwinding (FADU) was conducted and was proved to be an optimal method for studying DNA strand breaks induced by low dose irradiation. The linear dose response curve was obtained. The minimum detected dose was 0.3 Gy. There was no effect of low dose γ-rays (0.5∼8.0 cGy) on DNA strand breaks of quiescent and mitogen-induced lymphocytes. The 0.5∼4.0 cGy γ-rats could induce adaptive response of lymphocytes' DNA strand breaks, especially, at the doses of 2.0 and 4.0 cGy. The challenge doses of 5∼20 Gy could make the adaptive response appearance, and the 15 Gy was the best one. The 3-AB could powerfully inhibit the adaptive response. The repair of DNA strand breaks (37 degree C, 15∼60 min) caused by 15 Gy γ-rays could be promoted by the low dose γ-ray irradiation (2.0 cGy), but no difference was found at 37 degree C, 120 min

Hassall's corpuscles in the guinea-pig thymus after 60Co 2000R local irradiation

International Nuclear Information System (INIS)

Kinoshita, Hideo; Sugiyama, Shizuyuki; Shibata, Moritoshi; Ishibashi, Hirofumi; Uehara, Masaomi

1974-01-01

The cervical regions of male guinea pigs weighing about 300g were irradiated locally with 60 Co 2000 R and the animals were sacrificed on the 3rd, 5th, 7th and 9th days after the irradiation. The thymus was weighed and fixed in 10% formal saline. Tissues were blocked in paraffin and each block was cut into serial sections having a thickness of approximately 6 microns. These sections were stained by the haematoxylin-eosin (HE) and the aldehyde-fuchsin (AF) techniques. The size of Hassall's corpuscles was measured in the sections stained with haematoxylin-eosin and it was found that the weight of the thymus in 60 Co 2000 R irradiation decreased remarkably and that the tendency of Hassall's corpuscles to enlarge was more remarkable in the 2000 R group than in the 800 R group. (author)

Molecular nature of mutations induced by high-LET irradiation with argon and carbon ions in Arabidopsis thaliana

International Nuclear Information System (INIS)

Hirano, Tomonari; Kazama, Yusuke; Ohbu, Sumie; Shirakawa, Yuki; Liu Yang; Kambara, Tadashi; Fukunishi, Nobuhisa; Abe, Tomoko

2012-01-01

Linear energy transfer (LET) is an important parameter to be considered in heavy-ion mutagenesis. However, in plants, no quantitative data are available on the molecular nature of the mutations induced with high-LET radiation above 101–124 keV μm −1 . In this study, we irradiated dry seeds of Arabidopsis thaliana with Ar and C ions with an LET of 290 keV μm −1 . We analyzed the DNA alterations caused by the higher-LET radiation. Mutants were identified from the M 2 pools. In total, 14 and 13 mutated genes, including bin2, egy1, gl1, gl2, hy1, hy3–5, ttg1, and var2, were identified in the plants derived from Ar- and C-ions irradiation, respectively. In the mutants from both irradiations, deletion was the most frequent type of mutation; 13 of the 14 mutated genes from the Ar ion-irradiated plants and 11 of the 13 mutated genes from the C ion-irradiated plants harbored deletions. Analysis of junction regions generated by the 2 types of irradiation suggested that alternative non-homologous end-joining was the predominant pathway of repair of break points. Among the deletions, the proportion of large deletions (>100 bp) was about 54% for Ar-ion irradiation and about 64% for C-ion irradiation. Both current results and previously reported data revealed that the proportions of the large deletions induced by 290-keV μm −1 radiations were higher than those of the large deletions induced by lower-LET radiations (6% for 22.5–30.0 keV μm −1 and 27% for 101–124 keV μm −1 ). Therefore, the 290 keV μm −1 heavy-ion beams can effectively induce large deletions and will prove useful as novel mutagens for plant breeding and analysis of gene functions, particularly tandemly arrayed genes.

Molecular nature of mutations induced by high-LET irradiation with argon and carbon ions in Arabidopsis thaliana

Energy Technology Data Exchange (ETDEWEB)

Hirano, Tomonari; Kazama, Yusuke [Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Innovation Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Ohbu, Sumie; Shirakawa, Yuki; Liu Yang; Kambara, Tadashi; Fukunishi, Nobuhisa [Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Abe, Tomoko, E-mail: tomoabe@riken.jp [Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Innovation Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)

2012-07-01

Linear energy transfer (LET) is an important parameter to be considered in heavy-ion mutagenesis. However, in plants, no quantitative data are available on the molecular nature of the mutations induced with high-LET radiation above 101-124 keV {mu}m{sup -1}. In this study, we irradiated dry seeds of Arabidopsis thaliana with Ar and C ions with an LET of 290 keV {mu}m{sup -1}. We analyzed the DNA alterations caused by the higher-LET radiation. Mutants were identified from the M{sub 2} pools. In total, 14 and 13 mutated genes, including bin2, egy1, gl1, gl2, hy1, hy3-5, ttg1, and var2, were identified in the plants derived from Ar- and C-ions irradiation, respectively. In the mutants from both irradiations, deletion was the most frequent type of mutation; 13 of the 14 mutated genes from the Ar ion-irradiated plants and 11 of the 13 mutated genes from the C ion-irradiated plants harbored deletions. Analysis of junction regions generated by the 2 types of irradiation suggested that alternative non-homologous end-joining was the predominant pathway of repair of break points. Among the deletions, the proportion of large deletions (>100 bp) was about 54% for Ar-ion irradiation and about 64% for C-ion irradiation. Both current results and previously reported data revealed that the proportions of the large deletions induced by 290-keV {mu}m{sup -1} radiations were higher than those of the large deletions induced by lower-LET radiations (6% for 22.5-30.0 keV {mu}m{sup -1} and 27% for 101-124 keV {mu}m{sup -1}). Therefore, the 290 keV {mu}m{sup -1} heavy-ion beams can effectively induce large deletions and will prove useful as novel mutagens for plant breeding and analysis of gene functions, particularly tandemly arrayed genes.

Isolating the effect of radiation-induced segregation in irradiation-assisted stress corrosion cracking of austenitic stainless steels

International Nuclear Information System (INIS)

Busby, J.T.; Was, G.S.; Kenik, E.A.

2002-01-01

Post-irradiation annealing was used to help identify the role of radiation-induced segregation (RIS) in irradiation-assisted stress corrosion cracking (IASCC) by preferentially removing dislocation loop damage from proton-irradiated austenitic stainless steels while leaving the RIS of major and minor alloying elements largely unchanged. The goal of this study is to better understand the underlying mechanisms of IASCC. Simulations of post-irradiation annealing of RIS and dislocation loop microstructure predicted that dislocation loops would be removed preferentially over RIS due to both thermodynamic and kinetic considerations. To verify the simulation predictions, a series of post-irradiation annealing experiments were performed. Both a high purity 304L (HP-304L) and a commercial purity 304 (CP-304) stainless steel alloy were irradiated with 3.2 MeV protons at 360 deg. C to doses of 1.0 and 2.5 dpa. Following irradiation, post-irradiation anneals were performed at temperatures ranging from 400 to 650 deg. C for times between 45 and 90 min. Grain boundary composition was measured using scanning transmission electron microscopy with energy-dispersive spectrometry in both as-irradiated and annealed samples. The dislocation loop population and radiation-induced hardness were also measured in as-irradiated and annealed specimens. At all annealing temperatures above 500 deg. C, the hardness and dislocation densities decreased with increasing annealing time or temperature much faster than RIS. Annealing at 600 deg. C for 90 min removed virtually all dislocation loops while leaving RIS virtually unchanged. Cracking susceptibility in the CP-304 alloy was mitigated rapidly during post-irradiation annealing, faster than RIS, dislocation loop density or hardening. That the cracking susceptibility changed while the grain boundary chromium composition remained essentially unchanged indicates that Cr depletion is not the primary determinator for IASCC susceptibility. For the same

Tissue specific promoters improve the localization of radiation-inducible gene expression

International Nuclear Information System (INIS)

Hallahan, Dennis; Kataoka, Yasushi; Kuchibhotla, Jaya; Virudachalam, Subbu; Weichselbaum, Ralph

1996-01-01

expression was quantified in vascular endothelial cells from large vessel (HUVEC) and small vessels (HMEC). We found cell-type specificity of radiation-induction. The promoter region from the ELAM gene gave no expression in cells that were not of endothelial cell origin and x-ray-induction of ELAM in the endothelium required the NFkB binding cis-acting element. ELAM induction was achieved at doses as low as 1 Gy, whereas induction of other radiation inducible genes required 5 to 10 Gy. Cells transfected with the minimal promoter (plasmid pTK-CAT) demonstrated no radiation induction. Expression of the CMV-LacZ genetic construct that was used as a negative control in each transfection was not altered by x-irradiation. Moreover, intravenous administration of liposomes containing a reporter gene linked to the ELAM promoter and a transcriptional amplification system were induced specifically at sites of x-irradiation in an animal model. Conclusions: Activation of transcription of the ELAM-1 promoter by ionizing radiation is a means of activating gene therapy within the vascular endothelium and demonstrates the feasibility of treating vascular lesions with noninvasive procedures. Tissue specific promoters (e. g., ELAM-1) combined with radiation inducible gene therapy improves the localization of gene therapy expression. These results have applications in intravascular brachytherapy for the prevention of blood vessel restenosis

Magnetic circular dichroism study of electron-irradiation induced defects in InP

International Nuclear Information System (INIS)

Gislason, H.P.

1989-01-01

A strong magnetic circular dichroism (MCD) absorption band centered at 1.07 eV in electron irradiated InP is reported. Temperature and magnetic field dependence of the signal reveal that the centre giving rise to this band is a spin triplet. By simulating neutral and reverse bias conditions of junction measurements through a careful choice of irradiation dose and starting material, the MCD band is shown to have an annealing behaviour closely resembling that of the majority carrier traps which control the Fermi level position in n- and p-type InP. The 1.07 eV MCD band represents the first magneto-optical signal connected with this family of complex irradiation-induced defects in InP. (author) 19 refs., 5 figs., 1 tab

Hassall's corpuscles in the guinea-pig thymus after a second /sup 60/Co local irradiation

Energy Technology Data Exchange (ETDEWEB)

Kinoshita, H [Nara Medical Univ., Kashihara (Japan)

1974-12-01

The cervical regions of male guinea-pigs, weighing about 300 g, were irradiated locally with /sup 60/Co 800 R, and the same dose of irradiation was repeated a second time in each guinea pig at a different interval. Thereafter, an irradiated animal was sacrificed every other day for 2 weeks. Thymuses were weighed and fixed in 10 percent formal saline. Tissues were blocked in paraffin and each block was cut into serial sections having a thickness of approximately 6 microns. These sections were stained with the haematoxylin-eosin (HE) and the aldehyde-fuchsin (AF) techniques. The size of Hassall's corpuscles was measured in the sections of HE and the AF (+) ratio of Hassall's corpuscles was calculated in sections of AF. The ratio (%) of the number of AF (+) corpuscles to the total number of corpuscles seen in the entire microscopical field was called ''AF (+) ratio''. The weight of the twice irradiated thymuses decreased regardless of the interval from the first irradiation. The tendency of Hassall's corpuscles to enlarge during the period of enlargement of the corpuscles after first irradiation was increased by the second irradiation. The enlarged pattern of Hassall's corpuscles after a single irradiation of /sup 60/Co 800 R re-appeared when the animals were given a second irradiation on the 35th day. Concerning the AF (+) ratio of Hassall's corpuscles, the increasing pattern of AF (+) ratio such as after single irradiation of /sup 60/Co 800 R re-appeared when the animals were given a second irradiation on the 35th day, but no effect was observed during the process of enlargement and disintegration of Hassall's corpuscles after the second irradiation. The enlargement of Hassall's corpuscles is attributed not only to the process of lympholysis, but also to various other factors such as the number and size of the corpuscles and the stage in their life cycle.

Continuous in-situ measurements of fission fragment irradiation induced void swelling in Ni

International Nuclear Information System (INIS)

Lefakis, H.

1980-01-01

A novel simulation technique has been developed to study the early stages of irradiation induced void formation in metals. The technique makes use of fission fragment irradiation produced by doping with 235 U and irradiating in a thermal neutron flux under highly controlled irradiation-environmental conditions. Employment of a computer and a high temperature radiation resistant LVDT resulted in a high volumetric sensitivity and the production of continuous, in-situ void swelling data for bulk specimens. Results for Ni, used as a test-metal served to corroborate the technique in a number of ways including comparisons with (a) reactor data, (b) direct post-irradiation specimen length measurements and (c) TEM examinations of irradiated samples. The technique has several unique advantages and, in conjunction with other conventional methods, it offers the possibility of detailed evaluation of void nucleation and growth theories. In view of the present results no definitive answer may be given on the issue of the incubation period while checks with two theoretical models have yielded an order-of-magnitude agreement

Decrease of glucose-induced insulin secretion of pancreatic rat islets after irradiation in vitro

Energy Technology Data Exchange (ETDEWEB)

Heinzmann, D; Nadrowitz, R; Besch, W; Schmidt, W; Hahn, H J

1983-01-01

Irradiation of pancreatic rat islets up to a dose of 2.5 Gy did neither alter glucose-nor IBMX-induced insulin secretion studied in vitro. The insulin as well as glucagon content of irradiated islets were similar as in the control tissue. This was also true in islets irradiated with 25 Gy which were characterized by a decreased insulin secretion in the presence of glucose and IBMX, respectively. Since we did not find indications of an enhanced hormone output in the radiation medium, we want to suggest that higher irradiation doses affect insulin release of pancreatic islets in vitro. This observation has to be taken into account for application of radioimmunosuppression for transplantation.

Radiotherapy-induced anti-tumor immunity contributes to the therapeutic efficacy of irradiation and can be augmented by CTLA-4 blockade in a mouse model.

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Yuya Yoshimoto

Full Text Available PURPOSE: There is growing evidence that tumor-specific immune responses play an important role in anti-cancer therapy, including radiotherapy. Using mouse tumor models we demonstrate that irradiation-induced anti-tumor immunity is essential for the therapeutic efficacy of irradiation and can be augmented by modulation of cytotoxic T lymphocyte (CTL activity. METHODS AND MATERIALS: C57BL/6 mice, syngeneic EL4 lymphoma cells, and Lewis lung carcinoma (LL/C cells were used. Cells were injected into the right femurs of mice. Ten days after inoculation, tumors were treated with 30 Gy of local X-ray irradiation and their growth was subsequently measured. The effect of irradiation on tumor growth delay (TGD was defined as the time (in days for tumors to grow to 500 mm3 in the treated group minus that of the untreated group. Cytokine production and serum antibodies were measured by ELISA and flow cytometry. RESULTS: In the EL4 tumor model, tumors were locally controlled by X-ray irradiation and re-introduced EL4 cells were completely rejected. Mouse EL4-specific systemic immunity was confirmed by splenocyte cytokine production and detection of tumor-specific IgG1 antibodies. In the LL/C tumor model, X-ray irradiation also significantly delayed tumor growth (TGD: 15.4 days and prolonged median survival time (MST to 59 days (versus 28 days in the non-irradiated group. CD8(+ cell depletion using an anti-CD8 antibody significantly decreased the therapeutic efficacy of irradiation (TGD, 8.7 days; MST, 49 days. Next, we examined whether T cell modulation affected the efficacy of radiotherapy. An anti-CTLA-4 antibody significantly increased the anti-tumor activity of radiotherapy (TGD was prolonged from 13.1 to 19.5 days, while anti-FR4 and anti-GITR antibodies did not affect efficacy. CONCLUSIONS: Our results indicate that tumor-specific immune responses play an important role in the therapeutic efficacy of irradiation. Immunomodulation, including CTLA-4

Radiotherapy-Induced Anti-Tumor Immunity Contributes to the Therapeutic Efficacy of Irradiation and Can Be Augmented by CTLA-4 Blockade in a Mouse Model

Science.gov (United States)

Yoshimoto, Yuya; Suzuki, Yoshiyuki; Mimura, Kousaku; Ando, Ken; Oike, Takahiro; Sato, Hiro; Okonogi, Noriyuki; Maruyama, Takanori; Izawa, Shinichiro; Noda, Shin-ei; Fujii, Hideki; Kono, Koji; Nakano, Takashi

2014-01-01

Purpose There is growing evidence that tumor-specific immune responses play an important role in anti-cancer therapy, including radiotherapy. Using mouse tumor models we demonstrate that irradiation-induced anti-tumor immunity is essential for the therapeutic efficacy of irradiation and can be augmented by modulation of cytotoxic T lymphocyte (CTL) activity. Methods and Materials C57BL/6 mice, syngeneic EL4 lymphoma cells, and Lewis lung carcinoma (LL/C) cells were used. Cells were injected into the right femurs of mice. Ten days after inoculation, tumors were treated with 30 Gy of local X-ray irradiation and their growth was subsequently measured. The effect of irradiation on tumor growth delay (TGD) was defined as the time (in days) for tumors to grow to 500 mm3 in the treated group minus that of the untreated group. Cytokine production and serum antibodies were measured by ELISA and flow cytometry. Results In the EL4 tumor model, tumors were locally controlled by X-ray irradiation and re-introduced EL4 cells were completely rejected. Mouse EL4-specific systemic immunity was confirmed by splenocyte cytokine production and detection of tumor-specific IgG1 antibodies. In the LL/C tumor model, X-ray irradiation also significantly delayed tumor growth (TGD: 15.4 days) and prolonged median survival time (MST) to 59 days (versus 28 days in the non-irradiated group). CD8(+) cell depletion using an anti-CD8 antibody significantly decreased the therapeutic efficacy of irradiation (TGD, 8.7 days; MST, 49 days). Next, we examined whether T cell modulation affected the efficacy of radiotherapy. An anti-CTLA-4 antibody significantly increased the anti-tumor activity of radiotherapy (TGD was prolonged from 13.1 to 19.5 days), while anti-FR4 and anti-GITR antibodies did not affect efficacy. Conclusions Our results indicate that tumor-specific immune responses play an important role in the therapeutic efficacy of irradiation. Immunomodulation, including CTLA-4 blockade, may be a

Nucleolus degradation and growth induced by uv-microbeam irradiation of interphase cells grown in culture

International Nuclear Information System (INIS)

Sakharov, V.N.; Voronkova, N.

1976-01-01

In contrast to total cell irradiation, local UV-microbeam irradiation can stimulate a significant diminution in the irradiated mature nucleoli in interphase mammalian cells in culture. This diminution is accompanied by the concomitant expansion of the unirradiated nucleoli within the same nucleus, and the total nucleolar volume per nucleus does not change appreciably. It is suggested that these nucleolar volume changes are the result of the dispersion, migration, and redistribution of the nucleolar material between competitive nucleolar organizer regions of the interphase nucleus

Phases stability of shape memory alloys Cu based under irradiation

International Nuclear Information System (INIS)

Zelaya, Maria Eugenia

2006-01-01

The effects of irradiation on the relative phase stability of phases related by a martensitic transformation in copper based shape memory alloys were studied in this work.Different kind of particles and energies were employed in the irradiation experiments.The first kind of irradiation was performed with 2,6 MeV electrons, the second one with 170 keV and 300 keV Cu ions and the third one with swift heavy ions (Kr, Xe, Au) with energies between 200 and 600 MeV.Stabilization of the 18 R martensite in Cu-Zn-Al-Ni induced by electron irradiation was studied.The results were compared to those of the stabilization induced by quenching and ageing in the same alloy, and the ones obtained by irradiation in 18 R-Cu-Zn-Al alloys.The effects of Cu irradiation over b phase were analyzed with several electron microscopy techniques including: scanning electron microscopy (S E M), high resolution electron microscopy (H R E M), micro diffraction and X-ray energy dispersive spectroscopy (E D S). Structural changes in Cu-Zn-Al b phase into a closed packed structure were induced by Cu ion implantation.The closed packed structures depend on the irradiation fluence.Based on these results, the interface between these structures (closed packed and b) and the stability of disordered phases were analyzed. It was also compared the evolution of long range order in the Cu-Zn-Al and in the Cu-Zn-Al-Ni b phase as a function of fluence.The evolution of the g phase was also compared. Both results were discussed in terms of the mobility of irradiation induced point defects.Finally, the effects induced by swift heavy ions in b phase and 18 R martensite were studied. The results of the irradiation in b phase were qualitatively similar to those produced by irradiation with lower energies. On the contrary, nano metric defects were found in the irradiated 18 R martensite.These defects were characterized by H R E M.The characteristic contrast of the defects was associated to a local change in the

Delayed cell death, giant cell formation and chromosome instability induced by X-irradiation in human embryo cells

International Nuclear Information System (INIS)

Roy, K.; Kodama, Seiji; Suzuki, Keiji; Watanabe, Masami

1999-01-01

We studied X-ray-induced delayed cell death, delayed giant cell formation and delayed chromosome aberrations in normal human embryo cells to explore the relationship between initial radiation damage and delayed effect appeared at 14 to 55 population doubling numbers (PDNs) after X-irradiation. The delayed effect was induced in the progeny of X-ray survivors in a dose-dependent manner and recovered with increasing PDNs after X-irradiation. Delayed plating for 24 h post-irradiation reduced both acute and delayed lethal damage, suggesting that potentially lethal damage repair (PLDR) can be effective for relieving the delayed cell death. The chromosome analysis revealed that most of the dicentrics (more than 90%) observed in the progeny of X-ray survivors were not accompanied with fragments, in contrast with those observed in the first mitosis after X-irradiation. The present results indicate that the potentiality of genetic instability is determined during the repair process of initial radiation damage and suggest that the mechanism for formation of delayed chromosome aberrations by radiation might be different from that of direct radiation-induced chromosome aberrations. (author)

Recovery from radiation induced changes in some protein end-products in the liver and blood serum of irradiated rats

International Nuclear Information System (INIS)

Elkashef, H.S.; Roushdy, H.M.; Saada, H.N.; Abdelsamie, M.A.

1989-01-01

When rats were subjected to whole body gamma-irradiation at the dose of 5.5 Gy it caused significant changes in the content of urea and creatine the serum at 7 and 14 days postirradiation. In the liver significant changes were observed in the content of urea, creatine and creatinine at all post-irradiation days except the third day for urea and seventh day for creatine. Ten days pre-irradiation of the rats a mixture of 5 mg testosterone propionate and 10 mg of vitamin E was intraperitoneally injected. The results indicated that this mixture could help in obtaining complete recovery for radiation induced changes in the content of urea in both liver and serum of irradiated protected rats. Also this mixture provided good protection and caused recovery from radiation induced changes in the liver creatine on the third and seventh days after irradiation. But for serum creatine, the recovery was observed only on the third post irradiation day. The applied radiation dose did not induce any significant changes in the level of serum creatinine, while a partial recovery was noticed for liver creatinine in irradiated protected rats. The recovery process seems to be related to the radiosensitivity of the animal tissue, with the chemical structure of the radioprotector substances and the estimated compounds as well as the post-irradiation time intervals.3 tab

Irradiation induced tensile property change of SA 508 Cl. 3 reactor pressure vessel steels

International Nuclear Information System (INIS)

Chi, Se Hwan; Hong, Jun Hwa; Kuk, Il Hiun

1998-01-01

Irradiation induced tensile property change of four kinds of reactor pressure vessel steels manufactured by different steel refining process was compared based on the differences in the miniature tensile specimen tests were conducted for mechanical property measurement and optical microscope (OM) and transmission electron microscope (TEM) were used for microstructural characterization. Specimens were irradiated to a neutron fluence of 2.7 x 10 19 n/cm 2 (E ≥ 1 MeV) at 288 deg C. Investigation on the unirradiated microstructures showed largely a same microstructure in that tempered acicular bainite and ferrite with bainitic phase prevailing in the unirradiated condition. Ban-shaped segregations were also clearly observed except a kind of materials. A large difference in the unirradiated microstructure appeared in the grain size and carbide microstructure. Of carbide microstructures, noticeable differences were observed in the size and distribution of cementite, and bainitic lath microstructures. No noticeable changes were observed in the optical and thin film TEM microstructures after irradiation. Complicated microstructural state of heat treated bainitic low alloy microstructure prevents easy quantification of microstructural changes due to irradiation. Apparent differences, however, were observed in the results of mechanical testing. Results of tensile testing and hardness measurement show that a steel refined by vacuum carbon deoxidation (VCD) method exhibits the highest radiation hardening behavior. Some of mechanical testing results on irradiated materials were possible to understand based on the initial microstructure, but further investigations using a wide array of sophisticated tools (for example, SANS, APFIM) are required to understand and characterize irradiation induced defects that are responsible for irradiation hardening behavior but are not revealed by conventional TEM. (author)

Biological effect of penetration controlled irradiation with ion beams

Energy Technology Data Exchange (ETDEWEB)

Tanaka, Atsushi; Shimizu, Takashi; Kikuchi, Masahiro; Kobayashi, Yasuhiko; Watanabe, Hiroshi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Yamashita, Takao

1997-03-01

To investigate the effect of local irradiation with ion beams on biological systems, technique for penetration controlled irradiation has been established. The range in a target was controlled by changing the distance from beam window in the atmosphere, and could be controlled linearly up to about 31 {mu}m in biological material. In addition, the effects of the penetration controlled irradiations with 1.5 MeV/u C and He ions were examined using tobacco pollen. The increased frequency of leaky pollen produced by ion beams suggests that the efficient pollen envelope damages would be induced at the range-end of ion beams. (author)

γ-irradiation-induced mortality: protective effect of protease inhibitors in chickens and mice

International Nuclear Information System (INIS)

Palladino, M.A.; Galton, J.E.; Troll, W.; Thorbecke, G.J.

1982-01-01

Chickens (Gallus domesticus) were protected from the acute γ-irradiation-induced mortality (within 24 hours) by the proteolytic enzyme inhibitors, soy-bean trypsin inhibitor (SBTI), lima bean inhibitor (LBTI), antipain, α-N-benzoyl-L-arginine ethyl ester HCl (BAEE), trasylol, and leupeptin. Several other enzyme inhibitors, p-tosyl-L-arginine methyl ester HCl (TAME), α-tosyl-lysyl-chloromethyl ketone HCl (TLCK) and epsilon-amino caproic acid (EACA), did not protect. EACA even increased the mortality caused by γ-irradiation. The pattern of protective enzyme inhibitors suggests involvement of a kallikrein-like enzyme. SBTI and antipain also protected against low range lethal γ-irradiation exposures, 690 R in BALB/c and 880 R in SJL/J mice. It is suggested that enhanced vascular permeability, which in chickens is known to be the cause of the irradiation mortality during the first 24 hours, may also contribute to the mortality in mice during the first week after irradiation. (author)

Effects of x irradiation on estrogen-induced synthetic processes of the avian liver

International Nuclear Information System (INIS)

Holshouser, S.J.; Schjeide, O.A.; Briles, W.E.

1975-01-01

Effects of x irradiation on protein and lipid synthesis were studied, using estrogen-induced yolk protein syntheses by the avian liver as a test model. Female chickens, receiving a single sublethal whole-body exposure of 600 R of x irradiation at 5 wk of age, laid fewer and smaller eggs upon reaching maturity as compared to nonirradiated controls. However, chemical contents and ultracentrifuge patterns of yolk proteins were not found to be qualitatively different. Accordingly, the synthesis of no one major yolk protein appeared to be selectively inhibited by exposure of the bird to irradiation. Injection of Estrogenic Substances into hens over a period of 3 days resulted in a much greater enlargement of livers in control estrogenized birds than in irradiated estrogenized birds. Differences were also ascertained to exist between control and irradiated birds in terms of total liver RNA. This would seem to indicate a greater potential for synthesis of serum yolk protein precursors in nonirradiated estrogenized hens. (U.S.)

Irradiation and inhomogeneity effects on ductility and toughness of (ODS)-7 -13Cr steels

International Nuclear Information System (INIS)

Preininger, D.

2007-01-01

Full text of publication follows: The superimposed effect of irradiation defect and structural inhomogeneity formation on tensile ductility and dynamic toughness of ferritic-martensitic 7-13CrW(Mo)VTa(Nb) and oxide dispersion-strengthened (ODS)-7-13CrWVTa(Ti)- RAFM steels has been examined by work hardening and local stress/strain-induced ductile fracture models. Structural inhomogeneities which strongly promoting plastic instability and localized flow might be formed by the applied fabrication process, high dose irradiation and additionally further during deformation by enhanced local dislocation generation around fine particles or due to slip band formation with localized heating at high impact strain rates ε'. The work hardening model takes into account superimposed dislocation multiplication from stored dislocations, dispersions and also grain boundaries as well as annihilation by cross-slip. Analytical relations have been deduced from the model describing uniform ductility and ductile upper shelf energy (USE) observed from Charpy-impact testes. Especially, the influence of different irradiation defects like atomic clusters, dislocation loops and coherent chromium-rich α'- precipitates have been considered together with effects from strain rate as well as irradiation (TI) and test temperature TT. Strengthening by clusters and more pronounced by dislocation loops formed at higher TI>250 deg. C reduces uniform ductility and also distinctly stronger dynamic toughness USE. A superimposed hardening by the α'- formation in higher Cr containing 9-13Cr steels strongly reduces toughness assisted by a combined grain-boundary embrittlement with reduction of the ductile fracture stress. But that improves work hardening and uniform ductility as observed particularly due to nano-scale Y 2 O 3 - dispersions in ODS-RAFM steels. For ODS- steels additionally the strength-induced reduction of toughness is diminished by a combined microstructural-induced increase of the ductile

Role of L-carnitine in Ameliorating the Cadmium Chloride and/or Irradiation-Induced Testicular Toxicity

International Nuclear Information System (INIS)

Ramadan, L.A.