Recording of radiation-induced optical density changes in doped agarose gels with a CCD camera

International Nuclear Information System (INIS)

Tarte, B.J.; Jardine, P.A.; Van Doorn, T.

1996-01-01

Full text: Spatially resolved dose measurement with iron-doped agarose gels is continuing to be investigated for applications in radiotherapy dosimetry. It has previously been proposed to use optical methods, rather than MRI, for dose measurement with such gels and this has been investigated using a spectrophotometer (Appleby A and Leghrouz A, Med Phys, 18:309-312, 1991). We have previously studied the use of a pencil beam laser for such optical density measurement of gels and are currently investigating charge-coupled devices (CCD) camera imaging for the same purpose but with the advantages of higher data acquisition rates and potentially greater spatial resolution. The gels used in these studies were poured, irradiated and optically analysed in Perspex casts providing gel sections 1 cm thick and up to 20 cm x 30 cm in dimension. The gels were also infused with a metal indicator dye (xylenol orange) to render the radiation induced oxidation of the iron in the gel sensitive to optical radiation, specifically in the green spectral region. Data acquisition with the CCD camera involved illumination of the irradiated gel section with a diffuse white light source, with the light from the plane of the gel section focussed to the CCD array with a manual zoom lens. The light was also filtered with a green colour glass filter to maximise the contrast between unirradiated and irradiated gels. The CCD camera (EG and G Reticon MC4013) featured a 1024 x 1024 pixel array and was interfaced to a PC via a frame grabber acquisition board with 8 bit resolution. The performance of the gel dosimeter was appraised in mapping of physical and dynamic wedged 6 MV X-ray fields. The results from the CCD camera detection system were compared with both ionisation chamber data and laser based optical density measurements of the gels. Cross beam profiles were extracted from each measurement system at a particular depth (eg. 2.3 cm for the physical wedge field) for direct comparison. A

Ramipril mitigates radiation-induced impairment of neurogenesis in the rat dentate gyrus

International Nuclear Information System (INIS)

Jenrow, Kenneth A; Brown, Stephen L; Liu, Jianguo; Kolozsvary, Andrew; Lapanowski, Karen; Kim, Jae Ho

2010-01-01

Sublethal doses of whole brain irradiation (WBI) are commonly administered therapeutically and frequently result in late delayed radiation injuries, manifesting as severe and irreversible cognitive impairment. Neural progenitors within the subgranular zone (SGZ) of the dentate gyrus are among the most radiosensitive cell types in the adult brain and are known to participate in hippocampal plasticity and normal cognitive function. These progenitors and the specialized SZG microenvironment required for neuronal differentiation are the source of neurogenic potential in the adult dentate gyrus, and provide a continuous supply of immature neurons which may then migrate into the adjacent granule cell layer to become mature granule cell neurons. The extreme radiosensitivity of these progenitors and the SGZ microenvironment suggests the hippocampus as a prime target for radiation-induced cognitive impairment. The brain renin-angiotensin system (RAS) has previously been implicated as a potent modulator of neurogenesis within the SGZ and selective RAS inhibitors have been implicated as mitigators of radiation brain injury. Here we investigate the angiotensin converting enzyme (ACE) inhibitor, ramipril, as a mitigator of radiation injury in this context. Adult male Fisher 344 rats received WBI at doses of 10 Gy and 15 Gy. Ramipril was administered beginning 24 hours post-WBI and maintained continuously for 12 weeks. Ramipril produced small but significant reductions in the deleterious effects of radiation on progenitor proliferation and neuronal differentiation in the rat dentate gyrus following 10 Gy-WBI, but was not effective following 15 Gy-WBI. Ramipril also reduced the basal rate of neurogenesis within the SGZ in unirradiated control rats. Our results indicate that chronic ACE inhibition with ramipril, initiated 24 hours post-irradiation, may reduce apoptosis among SGZ progenitors and/or inflammatory disruption of neurogenic signaling within SGZ microenvironment, and

Radiation-induced coloration of nitro blue tetrazolium gel dosimeter for low dose applications

International Nuclear Information System (INIS)

Abdel-Fattah, A.A.; Beshir, W.B.; Hassan, H.M.; Soliman, Y.S.

2017-01-01

A radiochromic sensor of nitro blue tetrazolium (NBT) in gelatin was evaluated as a new gel dosimeter for radiation applications. The NBT gel has the advantage of visual color change from faint yellow to violet at low absorbed doses (10–1000 Gy). This color change appears as a result of the reduction of NBT to colored formazan then to diformazan species with further increase of absorbed doses. Responses of the gel at different NBT concentrations were analyzed at the absorption maximum centered at 527 nm. An increase of NBT concentrations in the gel enhances the radiation dose sensitivity. Energy dependent study implies the tissue equivalency of the gel in the energy range of 0.15–20 MeV. Dependence of the gel response on irradiation temperature, and color stability before and after irradiation were also studied. The combined uncertainty associated with the dose monitoring (10–1000 Gy) is 6.26% (2σ). Thus, the NBT gel shows its suitability for food irradiation, insect population control, and some food irradiation applications. - Highlights: • Preparation of nitro blue tetrazolium (NBT) gel for the dose range of 10–1000 Gy. • The sensitivity of it increases with increasing NBT concentrations. • The response of irradiated dosimeter is stable after 5 h from irradiation. • The prepared gel dosimeter is a tissue equivalent. • Its combined uncertainty is equal to 6.26% for 10–1000 Gy dose level.

Lack of Prophylactic Effects of Aloe Vera Gel on Radiation Induced Dermatitis in Breast Cancer Patients

Science.gov (United States)

Ahmadloo, Niloofar; Kadkhodaei, Behnam; Omidvari, Shapour; Mosalaei, Ahmad; Ansari, Mansour; Nasrollahi, Hamid; Hamedi, Sayed Hasan; Mohammadianpanah, Mohammad

2017-04-01

Purpose: Radiotherapy induced dermatitis is a common and sometimes serious side effect. We conducted a randomized study to understand whether the adjunctive use of aloe vera gel might reduce the prevalence and/or severity of radiotherapy induced dermatitis. Methods: One hundred patients with newly diagnosed breast cancer were randomized to receive aloe vera gel or nothing during adjuvant radiotherapy consisting of conventional external beam radiation using 6 MV mega voltage linear accelerator photons. The radiation portals were composed of breast fields in all patients and supraclavicular and posterior axillary fields in node positive cases. The total dose was 50 Gy with a daily fraction of 2 Gy, five fractions per week. Results: Dermatitis was first found among patients of both groups after week 2. In the aloe vera and control groups, 2/8 patients and 5/12 patients had dermatitis grade 1 after weeks 2 (P value = 0.240) and 3 (P value = 0.317). After the 4th week, the numbers were 18 and, 23 fordermatitis grade 1 and only 1 for grade 3 dermatitis (P value = 0.328). After the 5th week, 31, 12 and 2 patients in the aloe vera group and 36, 6 and 5 of the controls had grades 1, 2 and 3 dermatitis, respectively (P value = 0.488). Conclusion: Aloe vera exerted no positive effect on prevalence orseverity of radiation dermatitis in this study. Creative Commons Attribution License

Effects of gel composition on the radiation induced density change in PAG polymer gel dosimeters: a model and experimental investigations

International Nuclear Information System (INIS)

Hilts, M; Jirasek, A; Duzenli, C

2004-01-01

Due to a density change that occurs in irradiated polyacrylamide gel (PAG), x-ray computed tomography (CT) has emerged as a feasible method of performing polymer gel dosimetry. However, applicability of the technique is currently limited by low sensitivity of the density change to dose. This work investigates the effect of PAG composition on the radiation induced density change and provides direction for future work in improving the sensitivity of CT polymer gel dosimetry. A model is developed that describes the PAG density change (Δρ gel ) as a function of both polymer yield (%P) and an intrinsic density change, per unit polymer yield, that occurs on conversion of monomer to polymer (Δρ polymer ). %P is a function of the fraction of monomer consumed and the weight fraction of monomer in the unirradiated gel (%T). Applying the model to experimental CT and Raman spectroscopic data, two important fundamental properties of the response of PAG density to dose (Δρ gel dose response) are discovered. The first property is that Δρ polymer depends on PAG %C (cross-linking fraction of total monomer) such that low and high %C PAGs exhibit a higher Δρ polymer than do more intermediate %C PAGs. This relationship is opposite to the relationship of polymer yield to %C and is explained by the effect of %C on the type of polymer formed. The second property is that the Δρ gel dose response is linearly dependent on %T. From the model, the inference is that, at least for %T≤12%, monomer consumption and Δρ polymer depend solely on %C. In terms of optimizing CT polymer gel dosimetry for high sensitivity, these results indicate that Δρ polymer can be expected to vary with each polymer gel system and thus should be considered when choosing a polymer gel for CT gel dosimetry. However, Δρ polymer and %P cannot be maximized simultaneously and maximizing %P, by choosing gels with intermediate %C and high %T, is found to have the greatest impact on increasing the

Radiation-induced DNA damage and repair in radiosensitive and radioresistant human tumour cells measured by field inversion gel electrophoresis

International Nuclear Information System (INIS)

Smeets, M.F.M.A.; Mooren, E.H.M.; Begg, A.C.

1993-01-01

Radiation-induced DNA damage induction and repair was measured in two human squamous carcinoma cell lines with differing radiosensitivities. Experiments were carried out with field inversion gel electrophoresis (FIGE), adapted to measure DNA double strand break (DSB) induction and repair in unlabelled cells. The sensitivity of the method was increased by introducing a hybridization membrane into the agarose gel. Damaged DNA accumulated on one spot on the membrane resulting in high local concentrations. This DNA was quantified using radioactively-labelled total human DNA as a probe. Radiosensitivity differences at physiological temperatures could not be explained by differences in either induction or repair of DNA damage as measured by pulsed field gel electrophoresis. (author)

Scopolamine methylbromide mitigates radiation induced damage and lethality in zebrafish

International Nuclear Information System (INIS)

Shrivastava, Nitisha; Joshi, Jayadev; Ghosh, Subhajit; Dimri, Manali; Prem Kumar, Indracanti; Sehgal, Neeta

2014-01-01

In view of the strategic importance radiation countermeasures hold, the present study was undertaken to screen a collection of small molecule clinical compounds for possible radioprotective action using zebrafish as a model system. Preliminary screening in developing zebrafish embryos (24 hour post fertilization, (hpf)) using damage manifestations and survival as end point identified scopolamine methylbromide (SMB), a muscarinic receptor antagonist, as a potential radiomitigator. It was found to be optimal (60% survival advantage after 6 th post irradiation day) at a dose of 80 μM when added 3 h post 20 Gy exposure. Mechanistic studies suggested that SMB though exhibited no significant antioxidant potential, but was found to limit radiation induced apoptosis (pre G1 population) quantified through flow cytometry (6 and 5% reduction after 8 or 24 h after treatments) and annexin V staining (8% reduction). Further, quantitative analysis, using caspase 3 assay, revealed a 2.46 fold increase in apoptosis in irradiated group and treatment of irradiated zebrafish embryos with SMB led to a significant reduction in global apoptosis (1.7 fold; p<0.05) when compared to irradiated group. In silico studies based on structural and functional similarity with known radioprotectors suggested similarities with atropine, a known anti-inflammatory agent with muscarinic antagonism and radioprotective potential. In view of this SMB was tested, in silico, for possible anti-inflammatory action. Molecular docking studies revealed that SMB interacts (B.E-8.0 Kcal/mole) with cycloxygenase-2 (COX-2). In lieu of this, anti-inflammation activity was assessed through ChIN (chemically induced inflammation) method in 3 dpf (days post fertilization) embryos and SMB was found to significantly inhibit inflammation at all doses studied from 20-200 μM at 3 and 6 hpi (hours post inflammation). Overall the result suggests that scopolamine methylbromide mitigates radiation induced injury and lethality in

Influence of temperature in TL signal induced by gamma radiation in zircon prepared by sol gel via

International Nuclear Information System (INIS)

Salas, P.; Castano, V.M.; Mendoza A, D.; Gonzalez M, P.R.; Rosa C, E. de la

2000-01-01

In this work, it was realized a study of the temperature effects in thermoluminescent signal (Tl) induced by gamma radiation in zircon, which was prepared by the sol gel method. According to the obtained results, the zircon thermically treated at 500 C or over is sensitive to radiation. This sensitivity is increased when the temperature in study is augmented, moreover, the Tl spectra form also is modified with the temperature increment. The samples thermically treated at 750 C or over present a linear response in the dose interval 27 to 165 Gy; therefore, such materials result promissories for dosimetric purposes. (Author)

Ramipril mitigates radiation-induced impairment of neurogenesis in the rat dentate gyrus

Directory of Open Access Journals (Sweden)

Lapanowski Karen

2010-02-01

Full Text Available Abstract Background Sublethal doses of whole brain irradiation (WBI are commonly administered therapeutically and frequently result in late delayed radiation injuries, manifesting as severe and irreversible cognitive impairment. Neural progenitors within the subgranular zone (SGZ of the dentate gyrus are among the most radiosensitive cell types in the adult brain and are known to participate in hippocampal plasticity and normal cognitive function. These progenitors and the specialized SZG microenvironment required for neuronal differentiation are the source of neurogenic potential in the adult dentate gyrus, and provide a continuous supply of immature neurons which may then migrate into the adjacent granule cell layer to become mature granule cell neurons. The extreme radiosensitivity of these progenitors and the SGZ microenvironment suggests the hippocampus as a prime target for radiation-induced cognitive impairment. The brain renin-angiotensin system (RAS has previously been implicated as a potent modulator of neurogenesis within the SGZ and selective RAS inhibitors have been implicated as mitigators of radiation brain injury. Here we investigate the angiotensin converting enzyme (ACE inhibitor, ramipril, as a mitigator of radiation injury in this context. Methods Adult male Fisher 344 rats received WBI at doses of 10 Gy and 15 Gy. Ramipril was administered beginning 24 hours post-WBI and maintained continuously for 12 weeks. Results Ramipril produced small but significant reductions in the deleterious effects of radiation on progenitor proliferation and neuronal differentiation in the rat dentate gyrus following 10 Gy-WBI, but was not effective following 15 Gy-WBI. Ramipril also reduced the basal rate of neurogenesis within the SGZ in unirradiated control rats. Conclusions Our results indicate that chronic ACE inhibition with ramipril, initiated 24 hours post-irradiation, may reduce apoptosis among SGZ progenitors and/or inflammatory

Ultraviolet-B radiation induced cross-linking improves physical properties of cold- and warm-water fish gelatin gels and films.

Science.gov (United States)

Otoni, Caio G; Avena-Bustillos, Roberto J; Chiou, Bor-Sen; Bilbao-Sainz, Cristina; Bechtel, Peter J; McHugh, Tara H

2012-09-01

Cold- and warm-water fish gelatin granules were exposed to ultraviolet-B radiation for doses up to 29.7 J/cm(2). Solutions and films were prepared from the granules. Gel electrophoresis and refractive index were used to examine changes in molecular weight of the samples. Also, the gel strength and rheological properties of the solutions as well as the tensile and water vapor barrier properties of the films were characterized. SDS-PAGE and refractive index results indicated cross-linking of gelatin chains after exposure to radiation. Interestingly, UV-B treated samples displayed higher gel strengths, with cold- and warm-water fish gelatin having gel strength increases from 1.39 to 2.11 N and from 7.15 to 8.34 N, respectively. In addition, both gelatin samples exhibited an increase in viscosity for higher UV doses. For gelatin films, the cold-water fish gelatin samples made from irradiated granules showed greater tensile strength. In comparison, the warm-water gelatin films made from irradiated granules had lower tensile strength, but better water vapor barrier properties. This might be due to the UV induced cross-linking in warm-water gelatin that disrupted helical structures. Journal of Food Science copy; 2012 Institute of Food Technologists® No claim to original US government works.

Functionalizable Sol-Gel Silica Coatings for Corrosion Mitigation

Science.gov (United States)

Gąsiorek, Jolanta; Babiarczuk, Bartosz; Kaleta, Jerzy; Jones, Walis; Krzak, Justyna

2018-01-01

Corrosion is constantly a major problem of the world economy in the field of metal products, metal processing and other areas that utilise metals. Previously used compounds utilizing hexavalent chromium were amongst the most effective materials for corrosion protection but regulations have been recently introduced that forbid their use. Consequently, there is a huge drive by engineers, technologists and scientists from different disciplines focused on searching a new, more effective and environmentally-friendly means of corrosion protection. One novel group of materials with the potential to solve metal protection problems are sol-gel thin films, which are increasingly interesting as mitigation corrosion barriers. These environmentally-friendly and easy-to-obtain coatings have the promise to be an effective alternative to hexavalent chromium compounds using for anti-corrosion industrial coatings. In this review the authors present a range of different solutions for slow down the corrosion processes of metallic substrates by using the oxides and doped oxides obtained by the sol-gel method. Examples of techniques used to the sol-gel coating examinations, in terms of anti-corrosion protection, are also presented. PMID:29373540

Functionalizable Sol-Gel Silica Coatings for Corrosion Mitigation.

Science.gov (United States)

Gąsiorek, Jolanta; Szczurek, Anna; Babiarczuk, Bartosz; Kaleta, Jerzy; Jones, Walis; Krzak, Justyna

2018-01-26

Corrosion is constantly a major problem of the world economy in the field of metal products, metal processing and other areas that utilise metals. Previously used compounds utilizing hexavalent chromium were amongst the most effective materials for corrosion protection but regulations have been recently introduced that forbid their use. Consequently, there is a huge drive by engineers, technologists and scientists from different disciplines focused on searching a new, more effective and environmentally-friendly means of corrosion protection. One novel group of materials with the potential to solve metal protection problems are sol-gel thin films, which are increasingly interesting as mitigation corrosion barriers. These environmentally-friendly and easy-to-obtain coatings have the promise to be an effective alternative to hexavalent chromium compounds using for anti-corrosion industrial coatings. In this review the authors present a range of different solutions for slow down the corrosion processes of metallic substrates by using the oxides and doped oxides obtained by the sol-gel method. Examples of techniques used to the sol-gel coating examinations, in terms of anti-corrosion protection, are also presented.

Targeting the Renin–Angiotensin System Combined With an Antioxidant Is Highly Effective in Mitigating Radiation-Induced Lung Damage

Energy Technology Data Exchange (ETDEWEB)

Mahmood, Javed [Ontario Cancer Institute and the Campbell Family Institute for Cancer Research, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario (Canada); Radiation Medicine Program, STTARR Innovation Centre, Princess Margaret Cancer Centre, Toronto, Ontario (Canada); Jelveh, Salomeh [Radiation Medicine Program, STTARR Innovation Centre, Princess Margaret Cancer Centre, Toronto, Ontario (Canada); Zaidi, Asif [Ontario Cancer Institute and the Campbell Family Institute for Cancer Research, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario (Canada); Doctrow, Susan R. [Pulmonary Center, Department of Medicine, Boston University, Boston, Massachusetts (United States); Medhora, Meetha [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin (United States); Hill, Richard P., E-mail: hill@uhnres.utoronto.ca [Ontario Cancer Institute and the Campbell Family Institute for Cancer Research, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario (Canada); Departments of Medical Biophysics and Radiation Oncology, University of Toronto, Toronto, Ontario (Canada)

2014-07-15

Purpose: To investigate the outcome of suppression of the renin angiotensin system using captopril combined with an antioxidant (Eukarion [EUK]-207) for mitigation of radiation-induced lung damage in rats. Methods and Materials: The thoracic cavity of female Sprague-Dawley rats was irradiated with a single dose of 11 Gy. Treatment with captopril at a dose of 40 mg/kg/d in drinking water and EUK-207 given by subcutaneous injection (8 mg/kg daily) was started 1 week after irradiation (PI) and continuing until 14 weeks PI. Breathing rate was monitored until the rats were killed at 32 weeks PI, when lung fibrosis was assessed by lung hydroxyproline content. Lung levels of the cytokine transforming growth factor-β1 and macrophage activation were analyzed by immunohistochemistry. Oxidative DNA damage was assessed by 8-hydroxy-2-deoxyguanosine levels, and lipid peroxidation was measured by a T-BARS assay. Results: The increase in breathing rate in the irradiated rats was significantly reduced by the drug treatments. The drug treatment also significantly decreased the hydroxyproline content, 8-hydroxy-2-deoxyguanosine and malondialdehyde levels, and levels of activated macrophages and the cytokine transforming growth factor-β1 at 32 weeks. Almost complete mitigation of these radiation effects was observed by combining captopril and EUK-207. Conclusion: Captopril and EUK-207 can provide mitigation of radiation-induced lung damage out to at least 32 weeks PI after treatment given 1-14 weeks PI. Overall the combination of captopril and EUK-207 was more effective than the individual drugs used alone.

Radiation hardness of Ce-doped sol-gel silica fibers for high energy physics applications.

Science.gov (United States)

Cova, Francesca; Moretti, Federico; Fasoli, Mauro; Chiodini, Norberto; Pauwels, Kristof; Auffray, Etiennette; Lucchini, Marco Toliman; Baccaro, Stefania; Cemmi, Alessia; Bártová, Hana; Vedda, Anna

2018-02-15

The results of irradiation tests on Ce-doped sol-gel silica using x- and γ-rays up to 10 kGy are reported in order to investigate the radiation hardness of this material for high-energy physics applications. Sol-gel silica fibers with Ce concentrations of 0.0125 and 0.05 mol. % are characterized by means of optical absorption and attenuation length measurements before and after irradiation. The two different techniques give comparable results, evidencing the formation of a main broad radiation-induced absorption band, peaking at about 2.2 eV, related to radiation-induced color centers. The results are compared with those obtained on bulk silica. This study reveals that an improvement of the radiation hardness of Ce-doped silica fibers can be achieved by reducing Ce content inside the fiber core, paving the way for further material development.

Radiation hardening of sol gel-derived silica fiber preforms through fictive temperature reduction.

Science.gov (United States)

Hari Babu, B; Lancry, Matthieu; Ollier, Nadege; El Hamzaoui, Hicham; Bouazaoui, Mohamed; Poumellec, Bertrand

2016-09-20

The impact of fictive temperature (Tf) on the evolution of point defects and optical attenuation in non-doped and Er3+-doped sol-gel silica glasses was studied and compared to Suprasil F300 and Infrasil 301 glasses before and after γ-irradiation. To this aim, sol-gel optical fiber preforms have been fabricated by the densification of erbium salt-soaked nanoporous silica xerogels through the polymeric sol-gel technique. These γ-irradiated fiber preforms have been characterized by FTIR, UV-vis-NIR absorption spectroscopy, electron paramagnetic resonance, and photoluminescence measurements. We showed that a decrease in the glass fictive temperature leads to a decrease in the glass disorder and strained bonds. This mainly results in a lower defect generation rate and thus less radiation-induced attenuation in the UV-vis range. Furthermore, it was found that γ-radiation "hardness" is higher in Er3+-doped sol-gel silica compared to un-doped sol-gel silica and standard synthetic silica glasses. The present work demonstrates an effective strategy to improve the radiation resistance of optical fiber preforms and glasses through glass fictive temperature reduction.

Fourier transform Raman spectroscopy of polyacrylamide gels for radiation dosimetry

International Nuclear Information System (INIS)

Baldock, C.; Murry, P.; Pope, J.; Rintoul, L.; George, G.

1998-01-01

Polyacrylamide (PAG) gels are used in magnetic resonance imaging radiation dosimetry. The PAG dosimeter is based on the radiation-induced co-polymerisation and cross-linking of acrylic monomers infused in a gel matrix. PAG was manufactured with a composition of 5% gelatine, 3% acrylamide and 3% N,N'methylene-bis-acrylamide by mass, with distilled water as the remaining constituent [Baldock, 1998]. FT-Raman spectroscopy studies were undertaken to investigate cross-linking changes during the co-polymerisation of PAG in the spectral range of 200 - 3500 cm -1 . Vibrational bands of 1285 cm -1 and 1256 cm -1 were assigned to the acrylamide and bis-acrylamide single CH 2 δ CH2 binding modes. These bands were found to decrease in amplitude with increasing absorbed radiation dose, as a result of co-polymerisation. Principal Component Regression was performed on FT-Raman spectra of PAG samples irradiated to 50 Gy and two components were found to be sufficient to account for 98.7% of variance in the data. Cross validation was used to establish the absorbed radiation dose of an unknown PAG sample from the FT-Raman spectra. The calculated correlation coefficient between measured and predictive samples was 0.997 with a standard error of estimate of 0.976 and a standard error of prediction of 1.140. These results demonstrate the potential of FT-Raman spectroscopy for ionising radiation dosimetry using polyacrylamide gels

γ radiation induced changes in the bioadhesion properties of Ca-alginate gels

International Nuclear Information System (INIS)

Popeski-Dimovski, Riste

2009-01-01

The need for controlled release of drugs and their administration in specific zone of the organism asks for developing of carriers of drugs who will do the job. The two greatest needs, controlled release, and attention on the site, organ, of the organism that's treated its bioadhesion is best done with polymer gels. From the many choices of polymer gels, ether synthetic or natural the Na-alginate gels are the best suited because of their easy of access and good controlled release as being nontoxic to the living organisms and showing promising bioadhesion capability. Because of that examining the possibility for modification of the bioadhesion properties with gamma radiation is of interest. In this work Ca-alginate gels are irradiated with different absorbed doses to see if there will be any changes of the bioadhesion properties. For this mechanical compressibility tests and bioadhesion pull test are conducted on the irradiated samples. The results show that under irradiation gels louse their structural integrity becoming softer but the bioadhesive properties increase. But this increase is very small of up to 20% and its of no interest in practical circumstances where the practice is interested in changes of at least 100% and up, so changing the doses and properties of the gels to increase the bioadhesive properties might be of further interest. (Author)

Functionalizable Sol-Gel Silica Coatings for Corrosion Mitigation

Directory of Open Access Journals (Sweden)

Jolanta Gąsiorek

2018-01-01

Full Text Available Corrosion is constantly a major problem of the world economy in the field of metal products, metal processing and other areas that utilise metals. Previously used compounds utilizing hexavalent chromium were amongst the most effective materials for corrosion protection but regulations have been recently introduced that forbid their use. Consequently, there is a huge drive by engineers, technologists and scientists from different disciplines focused on searching a new, more effective and environmentally-friendly means of corrosion protection. One novel group of materials with the potential to solve metal protection problems are sol-gel thin films, which are increasingly interesting as mitigation corrosion barriers. These environmentally-friendly and easy-to-obtain coatings have the promise to be an effective alternative to hexavalent chromium compounds using for anti-corrosion industrial coatings. In this review the authors present a range of different solutions for slow down the corrosion processes of metallic substrates by using the oxides and doped oxides obtained by the sol-gel method. Examples of techniques used to the sol-gel coating examinations, in terms of anti-corrosion protection, are also presented.

Mitigation of radiation induced hematopoietic injury via regulation of Nrf-2 and increasing hematopoietic stem cells

International Nuclear Information System (INIS)

Patwardhan, R.S.; Sharma, Deepak; Checker, Rahul; Santosh Kumar, S.

2014-01-01

Therapeutic doses of ionizing radiation (IR) that can be delivered to tumors are restricted due to radiation induced damage to surrounding normal tissues thereby limiting the effectiveness of radiotherapy. Strategies to develop agents that selectively protect normal cells yielded limited success in the past. There is pressing need to develop safe, syndrome specific and effective radiation countermeasures to prevent or mitigate the harmful consequences of radiation exposure. Survival of bone marrow stem cells (HSCs) play a key role in protecting against IR induced hematopoietic injury. Many studies have shown manipulation of HSC frequency and/or survival as principal mechanism of radioprotection. It is known that, Nrf-2 plays crucial role in HSC survival and maintenance under oxidative stress conditions. In the present study, we have investigated the radioprotective ability of a flavonoid baicalein (5,6,7-trihydroxyflavone), extracted from the root of Scutellaria baicalensis Georgi, a medicinal plant traditionally used in Oriental medicine. There are numerous reports showing anti-inflammatory, anti-apoptotic, anti-oxidant, anti-cancer, anti-microbial, anti-mutagenic and neuroprotective properties of baicalein. Based on these reports, we have investigated the ability of baicalein to protect against radiation induced hematopoietic injury. Baicalein administration to mice protected against WBI induced mortality. Interestingly, the stem cell frequency increased in bone marrow cells obtained from baicalein administered mice as compared to vehicle treated mice. Baicalein treatment led to increased phospho-Nrf-2 levels in lineage negative BM-MNC. Administration of mice with Nrf-2 inhibitor prior to baicalein treatment led to significant abrogation of radioprotective ability of baicalein. This result suggests that, Nrf-2 may be playing a key role in baicalein mediated radioprotection. Here, we have shown that baicalein administration augments stem cell frequency, induces

Acemannan (a polysaccharides of Aloe vera gel) protects against radiation induced mortality by modulation of immunosuppression

International Nuclear Information System (INIS)

Kumar, Sumit; Tiku, Ashu Bhan

2014-01-01

Acemannan (poly-acetylated mannose) is an active component of Aloe vera gel and has been reported to have anticancerous, antimicrobial and shown to stimulate the development and proliferation of the hematopoietic cells. The anticancerous properties of acemannan have been attributed to the modulation of immune system rather then cytotoxicity. Therefore objective of the present study was to evaluate radioprotective efficacy of acemannan against radiation induced immune suppression using Swiss albino mice as a model system. For In-vivo studies mice were treated for 7 days orally prior to irradiation (5 Gy). Animals were sacrificed at different time point to study the effect on cellular proliferation, DNA damage, apoptosis and ROS level, cytokines level, antioxidant enzymes, nitric oxide and protein expression. For survival studies mice were treated with acemannan for 7 days pre or post irradiation and survival was monitored for 30 days. Acemannan showed a significant induction of proliferation of splenocytes in radiation treated groups. Beside a decrease in radiation induced ROS and DNA damage resulted in the reduction of apoptosis in murine splenocytes. Acemannan restored the antioxidant enzyme level (catalase, SOD, DTD and GST) and maintained the proper redox status via GSH, in irradiated mice. Further acemannan was shown to induce the hematopoiesis (peripheral lymphocytes cells, spleen colony cells, spleen index) by increasing the level of the pro-hematopoiesis cytokines (IL-1, TNF-α). Being an immunomodulator, acemannan reduced the level of the inflammation (IL-6, nitric oxide). Also the multiple mechanisms operational at cellular and molecule levelled to the reduction of radiation induced mortality of mice in both pre and post-irradiation studies. On the basis of the above results it can be concluded that radioprotective effects of the acemannan was due to its immunomodulatory activity and could have application for radio-therapeutic purposes. (author)

Dietary flaxseed administered post thoracic radiation treatment improves survival and mitigates radiation-induced pneumonopathy in mice

International Nuclear Information System (INIS)

Christofidou-Solomidou, Melpo; Cengel, Keith A; Tyagi, Sonia; Tan, Kay-See; Hagan, Sarah; Pietrofesa, Ralph; Dukes, Floyd; Arguiri, Evguenia; Heitjan, Daniel F; Solomides, Charalambos C

2011-01-01

Flaxseed (FS) is a dietary supplement known for its antioxidant and anti-inflammatory properties. Radiation exposure of lung tissues occurs either when given therapeutically to treat intrathoracic malignancies or incidentally, such as in the case of exposure from inhaled radioisotopes released after the detonation of a radiological dispersion devise (RDD). Such exposure is associated with pulmonary inflammation, oxidative tissue damage and irreversible lung fibrosis. We previously reported that dietary FS prevents pneumonopathy in a rodent model of thoracic X-ray radiation therapy (XRT). However, flaxseed's therapeutic usefulness in mitigating radiation effects post-exposure has never been evaluated. We evaluated the effects of a 10%FS or isocaloric control diet given to mice (C57/BL6) in 2 separate experiments (n = 15-25 mice/group) on 0, 2, 4, 6 weeks post a single dose 13.5 Gy thoracic XRT and compared it to an established radiation-protective diet given preventively, starting at 3 weeks prior to XRT. Lungs were evaluated four months post-XRT for blood oxygenation levels, inflammation and fibrosis. Irradiated mice fed a 0%FS diet had a 4-month survival rate of 40% as compared to 70-88% survival in irradiated FS-fed mouse groups. Additionally, all irradiated FS-fed mice had decreased fibrosis compared to those fed 0%FS. Lung OH-Proline content ranged from 96.5 ± 7.1 to 110.2 ± 7.7 μg/ml (Mean ± SEM) in all irradiated FS-fed mouse groups, as compared to 138 ± 10.8 μg/ml for mice on 0%FS. Concomitantly, bronchoalveolar lavage (BAL) protein and weight loss associated with radiation cachexia was significantly decreased in all FS-fed groups. Inflammatory cell influx to lungs also decreased significantly except when FS diet was delayed by 4 and 6 weeks post XRT. All FS-fed mice (irradiated or not), maintained a higher blood oxygenation level as compared to mice on 0%FS. Similarly, multiplex cytokine analysis in the BAL fluid revealed a significant decrease

Dietary flaxseed administered post thoracic radiation treatment improves survival and mitigates radiation-induced pneumonopathy in mice

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Arguiri Evguenia

2011-06-01

Full Text Available Abstract Background Flaxseed (FS is a dietary supplement known for its antioxidant and anti-inflammatory properties. Radiation exposure of lung tissues occurs either when given therapeutically to treat intrathoracic malignancies or incidentally, such as in the case of exposure from inhaled radioisotopes released after the detonation of a radiological dispersion devise (RDD. Such exposure is associated with pulmonary inflammation, oxidative tissue damage and irreversible lung fibrosis. We previously reported that dietary FS prevents pneumonopathy in a rodent model of thoracic X-ray radiation therapy (XRT. However, flaxseed's therapeutic usefulness in mitigating radiation effects post-exposure has never been evaluated. Methods We evaluated the effects of a 10%FS or isocaloric control diet given to mice (C57/BL6 in 2 separate experiments (n = 15-25 mice/group on 0, 2, 4, 6 weeks post a single dose 13.5 Gy thoracic XRT and compared it to an established radiation-protective diet given preventively, starting at 3 weeks prior to XRT. Lungs were evaluated four months post-XRT for blood oxygenation levels, inflammation and fibrosis. Results Irradiated mice fed a 0%FS diet had a 4-month survival rate of 40% as compared to 70-88% survival in irradiated FS-fed mouse groups. Additionally, all irradiated FS-fed mice had decreased fibrosis compared to those fed 0%FS. Lung OH-Proline content ranged from 96.5 ± 7.1 to 110.2 ± 7.7 μg/ml (Mean ± SEM in all irradiated FS-fed mouse groups, as compared to 138 ± 10.8 μg/ml for mice on 0%FS. Concomitantly, bronchoalveolar lavage (BAL protein and weight loss associated with radiation cachexia was significantly decreased in all FS-fed groups. Inflammatory cell influx to lungs also decreased significantly except when FS diet was delayed by 4 and 6 weeks post XRT. All FS-fed mice (irradiated or not, maintained a higher blood oxygenation level as compared to mice on 0%FS. Similarly, multiplex cytokine analysis in the

Dietary flaxseed administered post thoracic radiation treatment improves survival and mitigates radiation-induced pneumonopathy in mice

Energy Technology Data Exchange (ETDEWEB)

Christofidou-Solomidou, Melpo [Department of Medicine, Pulmonary Allergy and Critical Care Division, University of Pennsylvania Medical Center, Philadelphia, PA 19104 (United States); Cengel, Keith A [Radiation Oncology, University of Pennsylvania Medical Center, Philadelphia, PA 19104 (United States); Tyagi, Sonia [Department of Medicine, Pulmonary Allergy and Critical Care Division, University of Pennsylvania Medical Center, Philadelphia, PA 19104 (United States); Tan, Kay-See [Biostatistics & Epidemiology, University of Pennsylvania Medical Center, Philadelphia, PA 19104 (United States); Hagan, Sarah [Radiation Oncology, University of Pennsylvania Medical Center, Philadelphia, PA 19104 (United States); Pietrofesa, Ralph; Dukes, Floyd; Arguiri, Evguenia [Department of Medicine, Pulmonary Allergy and Critical Care Division, University of Pennsylvania Medical Center, Philadelphia, PA 19104 (United States); Heitjan, Daniel F [Biostatistics & Epidemiology, University of Pennsylvania Medical Center, Philadelphia, PA 19104 (United States); Solomides, Charalambos C [Department of Pathology, Jefferson University Hospital, Philadelphia, PA 19140 (United States)

2011-06-24

Flaxseed (FS) is a dietary supplement known for its antioxidant and anti-inflammatory properties. Radiation exposure of lung tissues occurs either when given therapeutically to treat intrathoracic malignancies or incidentally, such as in the case of exposure from inhaled radioisotopes released after the detonation of a radiological dispersion devise (RDD). Such exposure is associated with pulmonary inflammation, oxidative tissue damage and irreversible lung fibrosis. We previously reported that dietary FS prevents pneumonopathy in a rodent model of thoracic X-ray radiation therapy (XRT). However, flaxseed's therapeutic usefulness in mitigating radiation effects post-exposure has never been evaluated. We evaluated the effects of a 10%FS or isocaloric control diet given to mice (C57/BL6) in 2 separate experiments (n = 15-25 mice/group) on 0, 2, 4, 6 weeks post a single dose 13.5 Gy thoracic XRT and compared it to an established radiation-protective diet given preventively, starting at 3 weeks prior to XRT. Lungs were evaluated four months post-XRT for blood oxygenation levels, inflammation and fibrosis. Irradiated mice fed a 0%FS diet had a 4-month survival rate of 40% as compared to 70-88% survival in irradiated FS-fed mouse groups. Additionally, all irradiated FS-fed mice had decreased fibrosis compared to those fed 0%FS. Lung OH-Proline content ranged from 96.5 ± 7.1 to 110.2 ± 7.7 μg/ml (Mean ± SEM) in all irradiated FS-fed mouse groups, as compared to 138 ± 10.8 μg/ml for mice on 0%FS. Concomitantly, bronchoalveolar lavage (BAL) protein and weight loss associated with radiation cachexia was significantly decreased in all FS-fed groups. Inflammatory cell influx to lungs also decreased significantly except when FS diet was delayed by 4 and 6 weeks post XRT. All FS-fed mice (irradiated or not), maintained a higher blood oxygenation level as compared to mice on 0%FS. Similarly, multiplex cytokine analysis in the BAL fluid revealed a significant decrease of

DMA mitigates ionizing radiation induced damage in Balb/c mice through Akt/NFκB/PTEN pathway

International Nuclear Information System (INIS)

Tiwari, Vinod; Ranjan, Atul; Tandon, Vibha

2014-01-01

Ionizing radiation is associated with massive apoptosis in tumor as well as in radiosensitive organs. DMA, (5-(4-methylpiperazin-1-yl)-2-(2'-(3,4-dimethoxy-phenyl)-5'-benzimidazolyl) a cytoprotective radiomodulator, work in dual mode of action as free radical quencher and modifier of genomic instability caused by radiation. We observed 34% radioprotection with 50 mg/Kg bw intravenous dose of DMA in Balb/c mice at 8 Gy. DMA treatment before irradiation restored the normal crypts and villi architecture in Balb/c mice. The villi height was restored equivalent to control group in DMA treated animals, whereas, it was degenerated in irradiated animals. IR-induced apoptosis was reduced in spleen in presence of DMA as a result of preservation of splenic lymphocytes from radiation. This clearly exhibits the radioprotective ability of DMA to mitigate radiation induced tissue damage. IR-induced S phase check point was overcome by DMA. DMA promoted activation and phosphorylation of GSK3β through the activation of Akt in Balb/c mice. There was reduction in PTEN level in DMA pretreated mice where as it was upregulated in irradiated mice. Relative enhanced kinase activity of Akt was observed in DMA treated Balb/c mice and irradiated A549, MRC5 cell lines. There was no significant radioprotection in DMA treated Akt siRNA transfected cells in comparison to only Akt siRNA transfected cells with increasing dose of radiation. Akt activation was found in a dose-dependent manner by DMA through Luciferase reporter assay. We observed that DMA treated HEK cells transfected with control siRNA, resulted in less early apoptotic cells within 24h, but radiation (5 Gy) treated cells showed 20% early apoptotic cells within 3 h which were reduced to 12% at 3 h, 9% at 6 h and 8% at 24 h in DMA+radiation treated cells determined by Annexin V binding assay. Further molecular mRNA expression analysis of key regulatory genes unveil that DMA inhibited p21 and augmented Akt and Gadd45 in

Laser-induced transfer of gel microdroplets for cell printing

Science.gov (United States)

Yusupov, V. I.; Zhigar'kov, V. S.; Churbanova, E. S.; Chutko, E. A.; Evlashin, S. A.; Gorlenko, M. V.; Cheptsov, V. S.; Minaev, N. V.; Bagratashvili, V. N.

2017-12-01

We study thermal and transport processes involved in the transfer of gel microdroplets under the conditions of laser cell microprinting. The specific features of the interaction of pulsed laser radiation ( λ = 1.064 µm, pulse duration 4 - 200 ns, energy 2 µJ - 1 mJ) with the absorbing gold film deposited on the glass donor substrate are determined. The investigation of the dynamics of transport processes by means of fast optical video recording and optoacoustic methods makes it possible to determine the characteristics of the produced gel jets as functions of the laser operation regimes. The hydrodynamic process of interaction between the laser radiation and the gold coating with the hydrogel layer on it is considered and the temperature in the region of the laser pulse action is estimated. It is shown that in the mechanism of laser-induced transfer a significant role is played by the processes of explosive boiling of water (in gel) and gold. The amount of gold nanoparticles arriving at the acceptor plate in the process of the laser transfer is determined. For the laser pulse duration 8 ns and small energies (less than 10 µJ), the fraction of gold nanoparticles in the gel microdroplets is negligibly small, and their quantity linearly grows with increasing pulse energy. The performed studies offer a base for optimising the processes of laser transfer of gel microdroplets in the rapidly developing technologies of cell microprinting.

Radiation-induced DNA breaks detected by immuno labelling of poly(ADP-ribose) in CHO cells. Standardization by pulsed-field gel electrophoresis

International Nuclear Information System (INIS)

Varlet, P.; Bidon, N.; Noel, G.; Averbeck, D.; Salamero, J.; DeMurcia, G.

1998-01-01

The poly (ADP-ribose) polymerase is an ubiquitous nuclear protein capable of binding specifically to DNA strand breaks. It synthesizes ADP-ribose polymers proportionally to DNA breaks. The actual method of reference to determine DNA double strand breaks is pulsed-field gel electrophoresis, but this requires many cells. It thus appeared of interest to use poly (ADP-ribos)ylation to follow and estimate γ-ray-induced DNA fragmentation at the level of isolated cells after γ-irradiation in chinese hamster ovary cells (CHO-K1). The results obtained by the immuno-labelling technique of ADP-ribose polymers were compared to those obtained by pulsed-field gel electrophoresis. They show that poly (ADP-ribos)ylation reflects the occurrence of radiation-induced DNA strand breaks. A clear relationship exists between the amount of ADP-ribose polymers detected and DNA double strand breaks after γ-irradiation. (authors)

Segregation effect of radiation induced crosslinking of HDPE: morphology change

International Nuclear Information System (INIS)

Deng Pengyang; Zhong Xiaoguang

2000-01-01

Scanning Electronic Microscopy has been used to study morphology of pure gel; sol-gel blend and sol-gel segregation samples of radiation induced crosslinking of HDPE. The results show that the morphology of segregation sample is the same as that of pure gel and different from that of sol-gel blend. This kind of morphology change proves that the sol-gel blend have occurred a liquid---solid phase segregation in the melting state. The liquid phase (sol) will naturally immersed in the network of the gel. (author)

Detection of ultraviolet radiation using tissue equivalent radiochromic gel materials

International Nuclear Information System (INIS)

Bero, M A; Abukassem, I

2009-01-01

Ferrous Xylenol-orange Gelatin gel (FXG) is known to be sensitive to ionising radiation such as γ and X-rays. The effect of ionising radiation is to produce an increase in the absorption over a wide region of the visible spectrum, which is proportional to the absorbed dose. This study demonstrates that FXG gel is sensitive to ultraviolet radiation and therefore it could functions as UV detector. Short exposure to UV radiation produces linear increase in absorption measured at 550nm, however high doses of UV cause the ion indicator colour to fad away in a manner proportional to the incident UV energy. Light absorbance increase at the rate of 1.1% per minute of irradiation was monitored. The exposure level at which the detector has linear response is comparable to the natural summer UV radiation. Evaluating the UV ability to pass through tissue equivalent gel materials shows that most of the UV gets absorbed in the first 5mm of the gel materials, which demonstrate the damaging effects of this radiation type on human skin and eyes. It was concluded that FXG gel dosimeter has the potential to offer a simple, passive ultraviolet radiation detector with sensitivity suitable to measure and visualises the natural sunlight UV exposure directly by watching the materials colour changes.

Detection of ultraviolet radiation using tissue equivalent radiochromic gel materials

Science.gov (United States)

Bero, M. A.; Abukassem, I.

2009-05-01

Ferrous Xylenol-orange Gelatin gel (FXG) is known to be sensitive to ionising radiation such as γ and X-rays. The effect of ionising radiation is to produce an increase in the absorption over a wide region of the visible spectrum, which is proportional to the absorbed dose. This study demonstrates that FXG gel is sensitive to ultraviolet radiation and therefore it could functions as UV detector. Short exposure to UV radiation produces linear increase in absorption measured at 550nm, however high doses of UV cause the ion indicator colour to fad away in a manner proportional to the incident UV energy. Light absorbance increase at the rate of 1.1% per minute of irradiation was monitored. The exposure level at which the detector has linear response is comparable to the natural summer UV radiation. Evaluating the UV ability to pass through tissue equivalent gel materials shows that most of the UV gets absorbed in the first 5mm of the gel materials, which demonstrate the damaging effects of this radiation type on human skin and eyes. It was concluded that FXG gel dosimeter has the potential to offer a simple, passive ultraviolet radiation detector with sensitivity suitable to measure and visualises the natural sunlight UV exposure directly by watching the materials colour changes.

LGM2605 as a mitigator of space radiation-induced vascular damage, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — LignaMed, LLC is a drug development company with a fast track strategy to approval of LGM2605, an oral small molecule for use as a radiation mitigating agent that...

SEM studies of the structure of the gels prepared from untreated and radiation modified potato starch

International Nuclear Information System (INIS)

Cieśla, Krystyna; Sartowska, Bożena; Królak, Edward

2015-01-01

Potato starch was irradiated with a 60 Co gamma rays using doses of 5, 10, 20 and 30 kGy. Gels containing ca. 9.1% of starch were prepared by heating the starch suspensions in the heating chamber stabilized at 100 °C. Four procedures were applied for preparation of the samples in regard to SEM studies and the ability to observe the radiation effect by SEM was assessed for each method. Differences were observed between the SEM images recorded for the non-irradiated samples prepared using all the methods, and those irradiated. Images of the non-irradiated gels indicate generally a honey-comb structure, while smooth areas but with oriented fractures has appeared after irradiation. Modification of gel structure corresponds to the applied dose. The results were related to the process of gel formation (as observed by means of the hot stage microscope) to decrease in swelling power of the irradiated starch and to decreased viscosity of the resulting gels. It can be concluded that the differences in structural properties of gels shown by SEM result probably due to the better homogenization of the gels formed after radiation induced degradation. - Highlights: • Four procedures of the preservation of starch gels for SEM studies were applied. • The ability to observe the radiation effect by SEM was assessed for each method. • Dose dependent changes in the gel structure were discovered. • It was related to decrease in the swelling power and decreased viscosity of the gels. • A hot-stage microscope was applied in order to follow the gelatinization process

Study on radiation-induced polymerization of vinyl monomers adsorbed on inorganic substances. II. Radiation-induced polymerization of methyl methacrylate adsorbed on several inorganic substances

International Nuclear Information System (INIS)

Fukano, K.; Kageyama, E.

1975-01-01

The radiation-induced polymerization of methyl methacrylate (MMA) adsorbed on such inorganic substances as silica gel, white carbon, silicic acid anhydride, zeolite, and activated alumina was carried out to compare with the case of styrene. The rate of radiation-induced polymerization adsorbed on inorganic substances was high compared with that of radiation-induced bulk state polymerization, as was the case with styrene. Inorganic substrates which contain aluminum as a component element are more likely to be grafted than those which consist of SiO 2 alone, as with styrene. The molecular weight distribution of unextractable polymer and extractable polymer differs, depending on the type of inorganic substance. Experiments by a preirradiation method were carried out in case of silica gel, white carbon, and silicic acid anhydride. GPC spectra of the polymer obtained were different from those of polymer formed by the simultaneous irradiation method. It appears that all the unextractable polymer is grafted to the inorganic surface with chemical bond

Radiation-chemical and optical properties of a radio-fluorogenic gel

International Nuclear Information System (INIS)

Yao, Tiantian; Gasparini, Alessia; Denkova, Antonia G; Warman, John M

2015-01-01

The radiation-induced polymerization and fluorescence intensity of a radio- fluorogenic medium consisting of tertiary-butyl acrylate (TBA) with ca 100 ppm maleimido- pyrene (MPy) display a super-linear dependence on dose and a close to inverse square root dependence on dose rate over the range from 2 to 30 Gy/min. In contrast with the fluorescence, the clarity and optical absorption remain unchanged on irradiation up to at least 17% monomer conversion for which the medium is a rigid gel

Mitigating radiation damage of single photon detectors for space applications

Energy Technology Data Exchange (ETDEWEB)

Anisimova, Elena; Higgins, Brendon L.; Bourgoin, Jean-Philippe [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Physics and Astronomy, Waterloo, ON (Canada); Cranmer, Miles [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); Choi, Eric [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); Magellan Aerospace, Ottawa, ON (Canada); Hudson, Danya; Piche, Louis P.; Scott, Alan [Honeywell Aerospace (formerly COM DEV Ltd.), Ottawa, ON (Canada); Makarov, Vadim [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Physics and Astronomy, Waterloo, ON (Canada); University of Waterloo, Department of Electrical and Computer Engineering, Waterloo, ON (Canada); Jennewein, Thomas [University of Waterloo, Institute for Quantum Computing, Waterloo, ON (Canada); University of Waterloo, Department of Physics and Astronomy, Waterloo, ON (Canada); Canadian Institute for Advanced Research, Quantum Information Science Program, Toronto, ON (Canada)

2017-12-15

Single-photon detectors in space must retain useful performance characteristics despite being bombarded with sub-atomic particles. Mitigating the effects of this space radiation is vital to enabling new space applications which require high-fidelity single-photon detection. To this end, we conducted proton radiation tests of various models of avalanche photodiodes (APDs) and one model of photomultiplier tube potentially suitable for satellite-based quantum communications. The samples were irradiated with 106 MeV protons at doses approximately equivalent to lifetimes of 0.6, 6, 12 and 24 months in a low-Earth polar orbit. Although most detection properties were preserved, including efficiency, timing jitter and afterpulsing probability, all APD samples demonstrated significant increases in dark count rate (DCR) due to radiation-induced damage, many orders of magnitude higher than the 200 counts per second (cps) required for ground-to-satellite quantum communications. We then successfully demonstrated the mitigation of this DCR degradation through the use of deep cooling, to as low as -86 C. This achieved DCR below the required 200 cps over the 24 months orbit duration. DCR was further reduced by thermal annealing at temperatures of +50 to +100 C. (orig.)

Study of radiation-induced polymerization of vinyl monomers adsorbed on inorganic substances. VIII. Polymerization of styrene and methyl methacrylate adsorbed on aerosil

International Nuclear Information System (INIS)

Fukano, K.; Kageyama, E.

1976-01-01

Aerosol is silica having a purity which is very high compared with that of silica gel and having, unlike silica gel, no micropores. To investigate the effects of impurities and micropores on the radiation-induced polymerization of styrene and methyl methacrylate adsorbed on silica gel, the radiation-induced polymerization of styrene and methyl methacrylate adsorbed on Aerosil was carried out. The results of both the styrene--Aerosil 300 system and the methyl methacrylate--Aerosil 300 system were similar to those of the styrene-silica gel and methyl methacrylate-silica gel systems, respectively. This suggests that in the radiation-induced polymerization of both styrene--silica gel and methyl methacrylate--silica gel systems the impurities and the presence of micropores have almost no effect on the reaction mechanism. The effect of aluminum as an impurity was investigated on the styrene--Aerosil MOX 170 system. It was found that aluminum accelerated the cationic polymerization

Study on dose-effect relationship of radiation-induced DNA damage using single cell gel electrophoresis

International Nuclear Information System (INIS)

Liu Qiang; Jiang Enhai; Li Jin; Tang Weisheng; Wang Zhiquan; Zhao Yongcheng; Fan Feiyue

2006-01-01

Objective: To explore a new, simple and quick radiation biodosimeter, which can be applied to estimate biological dose in case of radiation accident. Methods: DNA double-strand break were detected using neutral single cell gel electrophoresis (SCGE), and all the indexes of comet assay including HDNA%, TDNA%, CL, TL, TM, and OTM were analyzed by CASP (Comet Assay Software Project). The curve of dose-effect was fitted using SPSS 12.0 software. Results: Statistically significant dose-effect relationships were observed in all the indexes of comet assay, OTM was superior to other indexes. Conclusions: Application of neutral comet assay combined with CASP analysis could serve as a new radiation biodosimeter. (authors)

Radioprotective effect of Rapana thomasiana hemocyanin in gamma induced acute radiation syndrome

International Nuclear Information System (INIS)

Kindekov, Ivan; Vassilieva, Vladimir; Aljakova, Mitko; Mileva, Milka; Krastev, Dimo; Raynova, Yuliana; Idakieva, Krassimira; Doumanov, Lyuba

2014-01-01

The radioprotective effect of Rapana thomasiana hemocyanin (RtH) against radiation-induced injuries (stomach ulcers, survival time and endogenous haemopoiesis) and post-radiation recovery was investigated in male albino mice (C3H strain). Radiation course was in a dose of 7.5 Gy (LD 100/30 - dose that kills 100% of the mice at 30 days) from "1"3"7Cs with a dose of 2.05 Gy/ min. Radiation injuries were manifested by inducing 2 hematopoietic form of acute radiation syndrome. RtH was administered intraperitoneally in a single dose of 50, 100, 150 and 200 mg/kg body weight (b. w.) once a day for five consecutive days before irradiation. The results obtained showed that radiation exposure led to (1) 100% mortality rate, (2) ulceration in the stomach mucosa and (3) decrease formation of spleen colonies as a marker of endogenous haemopoiesis. Administration of RtH at a dose of 200 mg/kg provided better protection against radiation-induced stomach ulceration, mitigated the lethal effects of radiation exposure and recovered endogenous haemopoiesis versus irradiated but not supplemented mice. It could be expected that RtH will find a use in mitigating radiation induced injury and enhanced radiorecovery. Keywords: Rapana thomasiana hemocyanin; acute radiation syndrome; radioprotective effect; spleen colony assay; stomach ulcerations

Combined Hydration and Antibiotics with Lisinopril to Mitigate Acute and Delayed High-dose Radiation Injuries to Multiple Organs.

Science.gov (United States)

Fish, Brian L; Gao, Feng; Narayanan, Jayashree; Bergom, Carmen; Jacobs, Elizabeth R; Cohen, Eric P; Moulder, John E; Orschell, Christie M; Medhora, Meetha

2016-11-01

The NIAID Radiation and Nuclear Countermeasures Program is developing medical agents to mitigate the acute and delayed effects of radiation that may occur from a radionuclear attack or accident. To date, most such medical countermeasures have been developed for single organ injuries. Angiotensin converting enzyme (ACE) inhibitors have been used to mitigate radiation-induced lung, skin, brain, and renal injuries in rats. ACE inhibitors have also been reported to decrease normal tissue complication in radiation oncology patients. In the current study, the authors have developed a rat partial-body irradiation (leg-out PBI) model with minimal bone marrow sparing (one leg shielded) that results in acute and late injuries to multiple organs. In this model, the ACE inhibitor lisinopril (at ~24 mg m d started orally in the drinking water at 7 d after irradiation and continued to ≥150 d) mitigated late effects in the lungs and kidneys after 12.5-Gy leg-out PBI. Also in this model, a short course of saline hydration and antibiotics mitigated acute radiation syndrome following doses as high as 13 Gy. Combining this supportive care with the lisinopril regimen mitigated overall morbidity for up to 150 d after 13-Gy leg-out PBI. Furthermore, lisinopril was an effective mitigator in the presence of the growth factor G-CSF (100 μg kg d from days 1-14), which is FDA-approved for use in a radionuclear event. In summary, by combining lisinopril (FDA-approved for other indications) with hydration and antibiotics, acute and delayed radiation injuries in multiple organs were mitigated.

Measurement of the ferric diffusion coefficient in agarose and gelatine gels by utilization of the evolution of a radiation induced edge as reflected in relaxation rate images

International Nuclear Information System (INIS)

Pedersen, Torje V.; Olsen, Dag R.; Skretting, Arne

1997-01-01

A method has been developed to determine the diffusion coefficients of ferric ions in ferrous sulphate doped gels. A radiation induced edge was created in the gel, and two spin-echo sequences were used to acquire a pair of images of the gel at different points of time. For each of these image pairs, a longitudinal relaxation rate image was derived. From profiles through these images, the standard deviations of the Gaussian functions that characterize diffusion were determined. These data provided the basis for the determination of the ferric diffusion coefficients by two different methods. Simulations indicate that the use of single spin-echo images in this procedure may in some cases lead to a significant underestimation of the diffusion coefficient. The technique was applied to different agarose and gelatine gels that were prepared, irradiated and imaged simultaneously. The results indicate that the diffusion coefficient is lower in a gelatine gel than in an agarose gel. Addition of xylenol orange to a gelatine gel lowers the diffusion coefficient from 1.45 to 0.81 mm 2 h -1 , at the cost of significantly lower R 1 sensitivity. The addition of benzoic acid to the latter gel did not increase the R 1 sensitivity. (author) OK

Radiotherapy gel dosimetry

International Nuclear Information System (INIS)

Baldock, C.

2002-01-01

shapes and sizes while sparing normal tissue. The situation is further complicated if the normal tissues are critical organs or are particularly sensitive to radiation. Radiotherapy techniques employed to obtain a closer conformation of the dose distribution to the tumour volume are referred to as conformal radiotherapy techniques. The clinical implementation of conformal therapy has been delayed by limitations in the verification of conformal dose distributions calculated by treatment planning systems prior to the irradiation of the patient and the verification of complex treatments during its delivery to the patient. There are several aspects of conformal therapy that complicate dose verification. To achieve the dose distributions conforming to complex 3D volumes, high dose gradients arise in the treatment volume. Further, overdose or underdose regions can exist when separate radiation fields are used to deliver additional radiation. These aspects require that practical dose measurement (dosimetry) techniques be able to integrate dose over time and easily measure dose distributions in 3D with high spatial resolution. Traditional dosimeters, such as ion chambers, thermoluminescent dosimeters and radiographic film do not fulfil these requirements. Novel gel dosimetry techniques are being developed in which dose distributions can potentially be determined in vitro in 3D using anthropomorphic phantoms to simulate a clinically irradiated situation. As long ago as the 1950's, radiation-induced colour change in dyes was used to investigate radiation doses in gels. It was subsequently shown that radiation induced changes in nuclear magnetic resonance (NMR) relaxation properties of gels infused with conventional Fricke dosimetry solutions could be measured using magnetic resonance imaging (MRI). In Fricke gels, Fe 2+ ions in ferrous sulphate solutions are usually dispersed throughout a gelatin, agarose or PVA matrix. Radiation-induced changes in the dosimeters are considered to

A synthetic superoxide dismutase/catalase mimetic EUK-207 mitigates radiation dermatitis and promotes wound healing in irradiated rat skin.

Science.gov (United States)

Doctrow, Susan R; Lopez, Argelia; Schock, Ashley M; Duncan, Nathan E; Jourdan, Megan M; Olasz, Edit B; Moulder, John E; Fish, Brian L; Mäder, Marylou; Lazar, Jozef; Lazarova, Zelmira

2013-04-01

In the event of a radionuclear attack or nuclear accident, the skin would be the first barrier exposed to radiation, though skin injury can progress over days to years following exposure. Chronic oxidative stress has been implicated as being a potential contributor to the progression of delayed radiation-induced injury to skin and other organs. To examine the causative role of oxidative stress in delayed radiation-induced skin injury, including impaired wound healing, we tested a synthetic superoxide dismutase (SOD)/catalase mimetic, EUK-207, in a rat model of combined skin irradiation and wound injury. Administered systemically, beginning 48 hours after irradiation, EUK-207 mitigated radiation dermatitis, suppressed indicators of tissue oxidative stress, and enhanced wound healing. Evaluation of gene expression in irradiated skin at 30 days after exposure revealed a significant upregulation of several key genes involved in detoxication of reactive oxygen and nitrogen species. This gene expression pattern was primarily reversed by EUK-207 therapy. These results demonstrate that oxidative stress has a critical role in the progression of radiation-induced skin injury, and that the injury can be mitigated by appropriate antioxidant compounds administered 48 hours after exposure.

The use of caspase inhibitors in pulsed-field gel electrophoresis may improve the estimation of radiation-induced DNA repair and apoptosis

International Nuclear Information System (INIS)

Balart, Josep; Pueyo, Gemma; Llobet, Lara I de; Baro, Marta; Sole, Xavi; Marin, Susanna; Casanovas, Oriol; Mesia, Ricard; Capella, Gabriel

2011-01-01

Radiation-induced DNA double-strand break (DSB) repair can be tested by using pulsed-field gel electrophoresis (PFGE) in agarose-encapsulated cells. However, previous studies have reported that this assay is impaired by the spontaneous DNA breakage in this medium. We investigated the mechanisms of this fragmentation with the principal aim of eliminating it in order to improve the estimation of radiation-induced DNA repair. Samples from cancer cell cultures or xenografted tumours were encapsulated in agarose plugs. The cell plugs were then irradiated, incubated to allow them to repair, and evaluated by PFGE, caspase-3, and histone H2AX activation (γH2AX). In addition, apoptosis inhibition was evaluated through chemical caspase inhibitors. We confirmed that spontaneous DNA fragmentation was associated with the process of encapsulation, regardless of whether cells were irradiated or not. This DNA fragmentation was also correlated to apoptosis activation in a fraction of the cells encapsulated in agarose, while non-apoptotic cell fraction could rejoin DNA fragments as was measured by γH2AX decrease and PFGE data. We were able to eliminate interference of apoptosis by applying specific caspase inhibitors, and improve the estimation of DNA repair, and apoptosis itself. The estimation of radiation-induced DNA repair by PFGE may be improved by the use of apoptosis inhibitors. The ability to simultaneously determine DNA repair and apoptosis, which are involved in cell fate, provides new insights for using the PFGE methodology as functional assay

Design Methodologies and to Combat Radiation Induced Corruption in FPGAs and SoCs, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Traditional radiation hardened by process (RHBP) and radiation hardened by design (RHBD) techniques have seen success in mitigating the effects of radiation induced...

Proton spectroscopic imaging of polyacrylamide gel dosimeters for absolute radiation dosimetry

International Nuclear Information System (INIS)

Murphy, P.S.; Schwarz, A.J.; Leach, M.O.

2000-01-01

Proton spectroscopy has been evaluated as a method for quantifying radiation induced changes in polyacrylamide gel dosimeters. A calibration was first performed using BANG-type gel samples receiving uniform doses of 6 MV photons from 0 to 9 Gy in 1 Gy intervals. The peak integral of the acrylic protons belonging to acrylamide and methylenebisacrylamide normalized to the water signal was plotted against absorbed dose. Response was approximately linear within the range 0-7 Gy. A large gel phantom irradiated with three, coplanar 3x3cm square fields to 5.74 Gy at isocentre was then imaged with an echo-filter technique to map the distribution of monomers directly. The image, normalized to the water signal, was converted into an absolute dose map. At the isocentre the measured dose was 5.69 Gy (SD = 0.09) which was in good agreement with the planned dose. The measured dose distribution elsewhere in the sample shows greater errors. A T 2 derived dose map demonstrated a better relative distribution but gave an overestimate of the dose at isocentre of 18%. The data indicate that MR measurements of monomer concentration can complement T 2 -based measurements and can be used to verify absolute dose. Compared with the more usual T 2 measurements for assessing gel polymerization, monomer concentration analysis is less sensitive to parameters such as gel pH and temperature, which can cause ambiguous relaxation time measurements and erroneous absolute dose calculations. (author)

Initial investigation of a novel light-scattering gel phantom for evaluation of optical CT scanners for radiotherapy gel dosimetry

International Nuclear Information System (INIS)

Bosi, Stephen; Naseri, Pourandokht; Puran, Alicia; Davies, Justin; Baldock, Clive

2007-01-01

There is a need for stable gel materials for phantoms used to validate optical computerized tomography (CT) scanners used in conjunction with radiation-induced polymerizing gel dosimeters. Phantoms based on addition of light-absorbing dyes to gelatine to simulate gel dosimeters have been employed. However, to more accurately simulate polymerizing gels one requires phantoms that employ light-scattering colloidal suspensions added to the gel. In this paper, we present the initial results of using an optical CT scanner to evaluate a novel phantom in which radiation-exposed polymer gels are simulated by the addition of colloidal suspensions of varying turbidity. The phantom may be useful as a calibration transfer standard for polymer gel dosimeters. The tests reveal some phenomena peculiar to light-scattering gels that need to be taken into account when calibrating polymer gel dosimeters

Radiation-induced change of optical property of hydroxypropyl cellulose hydrogel containing methacrylate compounds: As a basis for development of a new type of radiation dosimeter

International Nuclear Information System (INIS)

Yamashita, Shinichi; Hiroki, Akihiro; Taguchi, Mitsumasa

2014-01-01

Hydrogels with matrix of a cellulose derivative, hydrogel of hydroxpropyl cellulose (HPC), containing two of methacrylate compounds (2-hydroxyethyl methacrylate (HEMA) and poly(ethylene glycol) dimethacrylate (9G)) were irradiated with 60 Co γ-rays. The gels become white with irradiation, and thus, could be candidates of a new type of radiation dosimeter utilized in radiation therapy because the gels become white with irradiation and can be confirmed directly by human eyes even at low doses of 1–2 Gy. Radiation-induced change of optical properties, haze value and UV–vis absorption spectrum, of the irradiated gels was measured. Dose response of the white turbidity appearance was different for different compositions of the methacrylate compounds as well as for different dose rates. The degree of the radiation-induced white turbidity was quantified by measuring haze value, showing linear dose response in low dose region (<2 Gy). We also analyzed the gels with a UV–vis spectrometer and HEMA- and 9G-rich gels gave different spectral shapes, indicating that there are at least two mechanisms leading to the white turbidity. In addition, dose rate dependence was smaller for 9G-rich gels than HEMA-rich gels in the range of 0.015–1.5 Gy/min. - Highlights: • White turbidity appeared even at 1 or 2 Gy of 60 Co γ-ray irradiation. • Haze could be used as an index of the degree of white turbidity. • UV–vis spectroscopy indicated multiple mechanisms leading to white turbidity

Silver nitrate based gel dosimeter

International Nuclear Information System (INIS)

Titus, D; Samuel, E J J; Srinivasan, K; Roopan, S M; Madhu, C S

2017-01-01

A new radiochromic gel dosimeter based on silver nitrate and a normoxic gel dosimeter was investigated using UV-Visible spectrophotometry in the clinical dose range. Gamma radiation induced the synthesis of silver nanoparticles in the gel and is confirmed from the UV-Visible spectrum which shows an absorbance peak at around 450 nm. The dose response function of the dosimeter is found to be linear upto12Gy. In addition, the gel samples were found to be stable which were kept under refrigeration. (paper)

Emerging Radiation Health-Risk Mitigation Technologies

International Nuclear Information System (INIS)

Wilson, J.W.; Cucinotta, F.A.; Schimmerling, W.

2004-01-01

Past space missions beyond the confines of the Earth's protective magnetic field have been of short duration and protection from the effects of solar particle events was of primary concern. The extension of operational infrastructure beyond low-Earth orbit to enable routine access to more interesting regions of space will require protection from the hazards of the accumulated exposures of Galactic Cosmic Rays (GCR). There are significant challenges in providing protection from the long-duration exposure to GCR: the human risks to the exposures are highly uncertain and safety requirements places unreasonable demands in supplying sufficient shielding materials in the design. A vigorous approach to future radiation health-risk mitigation requires a triage of techniques (using biological and technical factors) and reduction of the uncertainty in radiation risk models. The present paper discusses the triage of factors for risk mitigation with associated materials issues and engineering design methods

Core Flight Executive Software Radiation Mitigation Study

Data.gov (United States)

National Aeronautics and Space Administration — The reliability of SmallSat / CubeSat missions may be increased by using software radiation mitigation for single event upsets (SEUs). Implementing protection in...

Correlation between γ-ray-induced DNA double-strand breakage and cell killing after biologically relevant doses: analysis by pulsed-field gel electrophoresis

International Nuclear Information System (INIS)

Murray, D.

1994-01-01

We examined the degree of correlation between γ-ray-induced lethality and DNA double-strand breaks (dsbs) after biologically relevant doses of radiation. Radiation lethality was modified by treating 14 C-labelled Chinese hamster ovary cells with either of two aminothiols (WR-1065 or WR-255591) and the associated effect on dsb induction was determined by pulsed-field gel electrophoresis (PFGE). The use of phosphorimaging to analyse the distribution of 14 C-activity in the gel greatly improved the low-dose resolution of the PFGE assay. Both WR-1065 and WR-255591 protected against dsb induction and lethality to a similar extent after low doses of radiation. although this correlation broke down when supralethal doses were used to induce dsbs. Thus, the level of dsbs induced in these cells as measured by PFGE after survival-curve doses of γ-radiation is consistently predictive of the degree of lethality obtained, implying a cause-effect relationship between these two parameters and confirming previous results obtained using the neutral filter elution assay for dsbs. (author)

Angiotensin converting enzyme inhibitors mitigate collagen synthesis induced by a single dose of radiation to the whole thorax

International Nuclear Information System (INIS)

Kma, L.; Gao, F.; Fish, B.L.; Moulder, J.E.; Jacobs, E.R.; Medhora, M.

2012-01-01

Our long-term goal is to use angiotensin converting enzyme (ACE) inhibitors to mitigate the increase in lung collagen synthesis that is induced by irradiation to the lung, which could result from accidental exposure or radiological terrorism. Rats (WAG/RijCmcr) were given a single dose of 13 Gy (dose rate of 1.43 Gy/min) of X-irradiation to the thorax. Three structurally-different ACE inhibitors, captopril, enalapril and fosinopril were provided in drinking water beginning 1 week after irradiation. Rats that survived acute pneumonitis (at 6-12 weeks) were evaluated monthly for synthesis of lung collagen. Other endpoints included breathing rate, wet to dry lung weight ratio, and analysis of lung structure. Treatment with captopril (145-207 mg/m 2 /day) or enalapril (19-28 mg/m 2 /day), but not fosinopril (19-28 mg/m 2 /day), decreased morbidity from acute pneumonitis. Lung collagen in the surviving irradiated rats was increased over that of controls by 7 months after irradiation. This increase in collagen synthesis was not observed in rats treated with any of the three ACE inhibitors. Analysis of the lung morphology at 7 months supports the efficacy of ACE inhibitors against radiation-induced fibrosis. The effectiveness of fosinopril against fibrosis, but not against acute pneumonitis, suggests that pulmonary fibrosis may not be a simple consequence of injury during acute pneumonitis. In summary, three structurally-different ACE inhibitors mitigate the increase in collagen synthesis 7 months following irradiation of the whole thorax and do so, even when therapy is started one week after irradiation. (author)

Radiation sensitive polymer gel dosimeters

International Nuclear Information System (INIS)

Lepage, M.; Back, S.A.J.; Baldock, C.; Whittaker, A.K.; Rintoul, L.

2000-01-01

Full text: Radiation sensitive gels are studied for their potential to retain a permanent 3D dose distribution for applications in radiotherapy. Co-monomers dissolved in a tissue-equivalent hydrogel undergo a polymerization reaction upon absorption of ionizing radiation. The polymer formed influences the local spin-spin relaxation time (T 2 ) of the dosimeter that can be determined using magnetic resonance imaging (MRI). The relationship between T2 and the absorbed dose was studied for different initial chemical compositions. The aim was to find a model linking the changes in T 2 with absorbed dose to the initial composition of the dosimeter. It is believed this will help designing new gel dosimeters having desired properties to minimize the uncertainty in the determination of the dose distribution. 1 H, 13 C nuclear magnetic resonance spectroscopy and FT-Raman spectroscopy were used to quantify the amount of monomers still remaining after the absorption of a given dose of radiation. This data is used to model the changes of T2 as a function of the absorbed dose. A model of fast exchange of magnetization between three proton pools was used, where the fraction of protons (f x H ) in the x th pool is obtained from the chemical composition of the dosimeter and the apparent T2 of each pool is determined for a given composition. Initially, the protons are contained in two pools; a mobile (mob), which contains the water protons and the monomers protons, and a gelatin (gela) proton pool. The mobile pool is partially depleted as polymer is formed, the protons are transferred into the polymer (pol) pool. In the figure, the experimental data along with the calculated values are plotted for three different monomer concentrations, with the gelatin concentration fixed. The model is seen to provide a good fit to the experimental data

Soft error mechanisms, modeling and mitigation

CERN Document Server

Sayil, Selahattin

2016-01-01

This book introduces readers to various radiation soft-error mechanisms such as soft delays, radiation induced clock jitter and pulses, and single event (SE) coupling induced effects. In addition to discussing various radiation hardening techniques for combinational logic, the author also describes new mitigation strategies targeting commercial designs. Coverage includes novel soft error mitigation techniques such as the Dynamic Threshold Technique and Soft Error Filtering based on Transmission gate with varied gate and body bias. The discussion also includes modeling of SE crosstalk noise, delay and speed-up effects. Various mitigation strategies to eliminate SE coupling effects are also introduced. Coverage also includes the reliability of low power energy-efficient designs and the impact of leakage power consumption optimizations on soft error robustness. The author presents an analysis of various power optimization techniques, enabling readers to make design choices that reduce static power consumption an...

Study on the kinetics of gel formation in the radiation crosslinking reaction

International Nuclear Information System (INIS)

Wang Mingjun; Liu Yuming

1988-01-01

From the kinetic equation of gel formation obtained by the authors, the mechanism of gel formation may be interpreted clearly as follows: (1) When the degree of crosslinking q g , the system is sol and the crosslinking reaction is only carried out between the sol molecules. (q g is the gel point). (2) When q=q g , there exists a beginning point where the gel is coexisted with the sol, and the system is still sol, and the crosslinking reaction is still carried out between the sol molecules. (3) When q>q g , the crosslinking reaction exceeds the gel point and the gel is coexisted with the sol. The kinetic equation shows clearly that the transformation from sol into gel is caused by crosslinking reaction of the uncrosslinked chain units between the sol and gel molecules. As a result the sol molecules are transformed into the gel molecules gradually, and the sol fraction is reduced. When the chain units P-barw(s)S(1-s)dq in sol are crosslinked with gel, the sol fraction in the system is reduced ds (where P-barw(s) is a function of the radiation dose and s is sol frection). The degree of crosslinking per unit dose (q 0 ) is a reduced function of dose (R). The equation for calculating its value for every irradiation dose is obtained. After knowing the correlation between P-bar W(s) vs R and q 0 vs R, the distribution of gel and sol in the process of radiation crosslinking can be discussed as well

Effect of heme oxygenase-1 on radiation-induced skin injury

International Nuclear Information System (INIS)

Song Chuanjun; Meng Xingjun; Xie Ling; Chen Qing; Zhou Jundong; Zhang Shuyu; Wu Jinchang

2012-01-01

Objective: To investigate the effect of heme oxygenase-1 (HO-1) on the acute radiation-induced skin injury by gene transfer. Methods: Thirty-three male SD rats were randomly divided into three groups as PBS-injected group, Ad-EGFP-injected group and Ad-HO-1-injected group (n=11). In each group, three rats were used for determining the expression of target gene and the other rats were irradiated on the buttock skin with 40 Gy electron beam generated by a linear accelerator. Immediately after irradiation, rats were administered with a subcutaneous injection of PBS, Ad-EGFP or Ad-HO-1, respectively. Subsequently, the skin reactions were measured twice a week using the semi-quantitative skin injury scale. Results: The strong positive expression of HO-1 was observed in subcutaneous dermal tissue after injection of Ad-HO-1. Compared to the PBS-injected group or the Ad-EGFP-injected group, a significant mitigation of skin injury was observed in Ad-HO-1-injected mice 14 d after irradiation (q=0.000-0.030, P<0.05). Conclusions: HO-1 could significantly mitigate radiation-induced acute skin injury and Ad-HO-1 could be used to treat radiation-induced skin injury. (authors)

How do monomeric components of a polymer gel dosimeter respond to ionising radiation: A steady-state radiolysis towards preparation of a 3D polymer gel dosimeter

International Nuclear Information System (INIS)

Kozicki, Marek

2011-01-01

Ionising radiation-induced reactions of aqueous single monomer solutions and mixtures of poly(ethylene glycol) diacrylate (PEGDA) and N,N'-methylenebisacrylamide (Bis) in a steady-state condition are presented below and above gelation doses in order to highlight reactions in irradiated 3D polymer gel dosimeters, which are assigned for radiotherapy dosimetry. Both monomers are shown to undergo radical polymerisation and cross-linking, which result in the measured increase in molecular weight and radius of gyration of the formed polydisperse polymer coils. The formation of nanogels was also observed for Bis solutions at a low concentration. In the case of PEGDA-Bis mixtures, co-polymerisation is suggested as well. At a sufficiently high radiation dose, the formation of a polymer network was observed for both monomers and their mixture. For this reason a sol-gel analysis for PEGDA and Bis was performed gravimetrically and a proposition of an alternative to this method employing a nuclear magnetic resonance technique is made. The two monomers were used for preparation of 3D polymer gel dosimeters having the acronyms PABIG and PABIG nx . The latter is presented for the first time in this work and is a type of the formerly established PABIG polymer gel dosimeter. The elementary characteristics of the new composition are presented, underlining the ease of its preparation, low dose threshold, and slightly increased sensitivity but lower quasi-linear range of dose response in comparison to PABIG. - Highlights: → Steady-state radiolysis of Bis, PEGDA and Bis-PEGDA is examined. → High Mw products are formed at low absorbed doses. → Formation of Bis nanogels is likely; PEGDA solutions form hydrogels. → NMR technique can be used for sol-gel analysis. → Features of 3D polymer gel dosimeters made from PEGDA and Bis are shown.

Cellulose gels produced in room temperature ionic liquids by ionizing radiation

International Nuclear Information System (INIS)

Kimura, Atsushi; Nagasawa, Naotsugu; Taguchi, Mitsumasa

2014-01-01

Cellulose-based gels were produced in room temperature ionic liquids (RTILs) by ionizing radiation. Cellulose was dissolved at the initial concentration of 20 wt% in 1-ethyl-3-methylimidazolium (EMI)-acetate or N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium (DEMA)-formate with a water content of 18 wt%, and irradiated with γ-rays under aerated condition to produce new cellulose gels. The gel fractions of the cellulose gels obtained in EMI-acetate and DEMA-formate at a dose of 10 kGy were 13% and 19%, respectively. The formation of gel fractions was found to depend on the initial concentration of cellulose, water content, and irradiation temperature. The obtained gel readily absorbed water, methanol, ethanol, dichloromethane, N,N-dimethylacetamide, and RTILs. - Highlights: • Cellulose gels were produced in room temperature ionic liquids (RTILs). • Water plays a crucial role in the cross-linking reaction. • Cellulose gels swollen with RTILs show good electronic conductivity (3.0 mS cm −1 )

Manufacturing of different gel detectors and their calibration for spatial radiation dose measurements

International Nuclear Information System (INIS)

Bero, M.

2008-05-01

Three types of gel dosemeter have been made and their most important properties for radiation dosimetry were studied. The comparison between the three categories helps to widen knowledge in each of these detectors and to establish a method for the preparation as well as testing of this radiation sensitive materials. Experiments show the technical application possibility for using these gel detectors to measure the spatial radiation dose distribution in the range of doses given for cancer treatment. The experimental results give some important characteristic for the three gel dosemeter used in comparison to that of the traditional dosimetry systems. It also shows the simplicity of manufacturing the dosemeter from low cost materials and its radiation response to ionizing. The relationships between the dosemeter response and the dose rate as well as the radiation energy were also investigated. Important subjects that have been also taken into consideration are the effects of ambient conditions and storage likelihood of the studied materials. Recommendation was made for the use of these materials in practical applications and for handling as well as their long term storage possibility. (author)

Low dose radiation induced protein and its experimental and ophthalmic clinical research

International Nuclear Information System (INIS)

Shen Wei; Su Liaoyuan; Liu Fenju; Ding Jie; Li Longbiao; Pan Chengsi

2001-01-01

The protective effects of low dose radiation (LDR) induced protein on cellular impairments caused by some harmful chemical and physical factors were studied. Male Kunming mice were irradiated with LDR, then the spleen cells of the mice were broken with ultrasonic energy and then ultracentrifugalized. The supernatant solution contained with LDR induced protein. The newly emerging protein was detected by gel filtration and its molecular weight was determined by gel electrophoresis. The content of newly emerging protein (LDR induced protein) was determined by Lowry's method. The method of isotope incorporation was used to observe the biological activity and its influence factors, the protective effects of LDR induced protein on the cells impaired by irradiating with ultraviolet (UV), high doses of 60 Co γ-rays and exposed to heat respectively, and the stimulative effects of LDR induced protein on human peripheral blood lymphocytes. Newly emerging protein has been observed in the experiment. The molecular weight of the protein is in the region 76.9 KD+- - 110.0 KD+-, the yield of the protein was 613.33 +- 213.42 μg per 3 x 10 7 spleen cells. DPM values (isotope were incorporated) of normal and injured mice spleen cells increased significantly after stimulating with the solution contained LDR induced protein. It is concluded that LDR induced protein could be obtained from mice spleen cells exposed to 5 - 15 cGy radiation for 2 - 16 h. The protein had biological activity and was able to stimulate the transformation of the spleen cells in vitro. It had obvious protective effects on some impaired cells caused by high dose radiation, UV radiation, heat and so on. It also had stimulative effects on the transformation of peripheral blood T and B lymphocytes of healthy individual and patients with eye diseases. It indicates that LDR induced protein increased immune function of human

Radiation Induced Crosslinking of Polyethylene in the Presence of Bifunctional Vinyl Monomers

DEFF Research Database (Denmark)

Joshi, M. S.; Singer, Klaus Albert Julius; Silverman, J.

1977-01-01

Several reports have been published showing that the radiation induced grafting of bifunctional vinyl monomers to low density polyethylene results in a product with an unusually high density of crosslinks. The same grafting reactions are shown to reduce the incipient gel dose by more than a factor...... of fifty. This paper is concerned with the apparent crosslinking produced by the radiation grafting of two monomers to polyethylene: acrylic acid and acrylonitrile....

A comparative analysis of longitudinal computed tomography and histopathology for evaluating the potential of mesenchymal stem cells in mitigating radiation-induced pulmonary fibrosis.

Science.gov (United States)

Perez, Jessica R; Lee, Sangkyu; Ybarra, Norma; Maria, Ola; Serban, Monica; Jeyaseelan, Krishinima; Wang, Li Ming; Seuntjens, Jan; Naqa, Issam El

2017-08-22

Radiation-induced pulmonary fibrosis (RIPF) is a debilitating side effect that occurs in up to 30% of thoracic irradiations in breast and lung cancer patients. RIPF remains a major limiting factor to dose escalation and an obstacle to applying more promising new treatments for cancer cure. Limited treatment options are available to mitigate RIPF once it occurs, but recently, mesenchymal stem cells (MSCs) and a drug treatment stimulating endogenous stem cells (GM-CSF) have been investigated for their potential in preventing this disease onset. In a pre-clinical rat model, we contrasted the application of longitudinal computed tomography (CT) imaging and classical histopathology to quantify RIPF and to evaluate the potential of MSCs in mitigating RIPF. Our results on histology demonstrate promises when MSCs are injected endotracheally (but not intravenously). While our CT analysis highlights the potential of GM-CSF treatment. Advantages and limitations of both analytical methods are contrasted in the context of RIPF.

Gel Dosimetry Analysis of Gold Nanoparticle Application in Kilovoltage Radiation Therapy

International Nuclear Information System (INIS)

Marques, T; Schwarcke, M; Garrido, C; Zucolot, V; Baffa, O; Nicolucci, P

2010-01-01

In this work gold nanoparticles (AuNP) were embedded in MAGIC-f gel and irradiated in a 250 kV x-ray clinical beam. The signal of non-irradiated gel samples containing AuNPs showed maximum difference of 0.5% related to gel without nanoparticles. Different AuNPs concentrations were studied: 0.10 mM, 0.05 mM and 0.02 mM, presenting dose enhancements of 106%, 90% and 77% respectively. Monte Carlo spectrometry was performed to quantify theoretical changes in photon energy spectrums due to AuNPs presence. Concordance between simulated dose enhancements and gel dosimetry measurements was better than 97% to all concentrations studied. This study evidences that polymer gel dosimetry as a suitable tool to perform dosimetric investigations of nanoparticle applications in Radiation Therapy.

Alpha-tocopherol succinate- and AMD3100-mobilized progenitors mitigate radiation combined injury in mice

International Nuclear Information System (INIS)

Singh, Vijay K.; Wise, Stephen Y.; Fatanmi, Oluseyi O.; Beattie, Lindsay A.; Ducey, Elizabeth J.; Seed, Thomas M.

2014-01-01

The purpose of this study was to elucidate the role of alpha-tocopherol succinate (TS)- and AMD3100-mobilized progenitors in mitigating combined injury associated with acute radiation exposure in combination with secondary physical wounding. CD2F1 mice were exposed to high doses of cobalt-60 gamma-radiation and then transfused intravenously with 5 million peripheral blood mononuclear cells (PBMCs) from TS- and AMD3100-injected mice after irradiation. Within 1 h after irradiation, mice were exposed to secondary wounding. Mice were observed for 30 d after irradiation and cytokine analysis was conducted by multiplex Luminex assay at various time-points after irradiation and wounding. Our results initially demonstrated that transfusion of TS-mobilized progenitors from normal mice enhanced survival of acutely irradiated mice exposed 24 h prior to transfusion to supralethal doses (11.5–12.5 Gy) of 60 Co gamma-radiation. Subsequently, comparable transfusions of TS-mobilized progenitors were shown to significantly mitigate severe combined injuries in acutely irradiated mice. TS administered 24 h before irradiation was able to protect mice against combined injury as well. Cytokine results demonstrated that wounding modulates irradiation-induced cytokines. This study further supports the conclusion that the infusion of TS-mobilized progenitor-containing PBMCs acts as a bridging therapy in radiation-combined-injury mice. We suggest that this novel bridging therapeutic approach involving the infusion of TS-mobilized hematopoietic progenitors following acute radiation exposure or combined injury might be applicable to humans. (author)

Sci—Fri PM: Dosimetry—01: Radiation-induced refraction artefacts in the optical CT readout of polymer gel dosimeters

International Nuclear Information System (INIS)

Campbell, Warren G; Jirasek, Andrew; Wells, Derek M

2014-01-01

Polymer gel dosimeters (PGDs) are a desirable tool for the verification of advanced radiotherapy treatments. Fully 3D, deformable, and tissue-equivalent, the PGD polymerizes wherever it absorbs dose. To measure the dose absorbed by a PGD, optical computed tomography (CT) can be used to evaluate, in full 3D, the opacity distribution that coincides with polymerization. In addition to an increase in opacity with dose, an increase in refractive index (RI) is also known to occur in irradiated polymer gels. The increase in RI is slight and was previously assumed insignificant. This work reveals the effects that radiation-induced RI changes can have on the optical CT readout of PGDs. A fan-beam optical CT scanner was used to image a cylindrical PGD irradiated by a pair of 3×3 cm 2 , 6 MV photon beams in an orthogonal arrangement. Investigative scans were performed to evaluate refraction errors occurring: i) within the plane, and ii) out of the plane of the fan-beam. In-plane refraction was shown to cause distinct streaking artefacts along dose gradients (i.e. RI gradients) due to higher intensity rays being refracted into more opaque regions. Out-of-plane refraction was shown to produce severe, widespread artefacts due to rays missing the detector array. An iterative Savitzky-Golay filtering technique was developed to reduce both types of artefacts by specifically targeting structured errors in sinogram space. Results introduce a new category of imaging artefacts to be aware of when using optical CT for PGD readout

Successful Mitigation of Delayed Intestinal Radiation Injury Using Pravastatin is not Associated with Acute Injury Improvement or Tumor Protection

International Nuclear Information System (INIS)

Haydont, Valerie; Gilliot, Olivier; Rivera, Sofia; Bourgier, Celine; Francois, Agnes; Aigueperse, Jocelyne; Bourhis, Jean; Vozenin-Brotons, Marie-Catherine

2007-01-01

Purpose: To investigate whether pravastatin mitigates delayed radiation-induced enteropathy in rats, by focusing on the effects of pravastatin on acute cell death and fibrosis according to connective tissue growth factor (CTGF) expression and collagen inhibition. Methods and Materials: Mitigation of delayed radiation-induced enteropathy was investigated in rats using pravastatin administered in drinking water (30 mg/kg/day) 3 days before and 14 days after irradiation. The ileum was irradiated locally after surgical exteriorization (X-rays, 19 Gy). Acute apoptosis, acute and late histologic alterations, and late CTGF and collagen deposition were monitored by semiquantitative immunohistochemistry and colorimetric staining (6 h, 3 days, 14 days, 15 weeks, and 26 weeks after irradiation). Pravastatin antitumor action was studied in HT-29, HeLa, and PC-3 cells by clonogenic cell survival assays and tumor growth delay experiments. Results: Pravastatin improved delayed radiation enteropathy in rats, whereas its benefit in acute and subacute injury remained limited (6 h, 3 days, and 14 days after irradiation). Delayed structural improvement was associated with decreased CTGF and collagen deposition but seemed unrelated to acute damage. Indeed, the early apoptotic index increased, and severe subacute structural damage occurred. Pravastatin elicited a differential effect, protecting normal intestine but not tumors from radiation injury. Conclusion: Pravastatin provides effective protection against delayed radiation enteropathy without interfering with the primary antitumor action of radiotherapy, suggesting that clinical transfer is feasible

Fungal beta glucan protects radiation induced DNA damage in human lymphocytes.

Science.gov (United States)

Pillai, Thulasi G; Maurya, Dharmendra K; Salvi, Veena P; Janardhanan, Krishnankutty K; Nair, Cherupally K K

2014-02-01

Ganoderma lucidum (Ling Zhi), a basidiomycete white rot macrofungus has been used extensively for therapeutic use in China, Japan, Korea and other Asian countries for 2,000 years. The present study is an attempt to investigate its DNA protecting property in human lymphocytes. Beta glucan (BG) was isolated by standard procedure and the structure and composition were studied by infrared radiation (IR) and nuclear magnetic resonance (NMR) spectroscopy, gel filtration chromatography and paper chromatography. The radioprotective properties of BG isolated from the macro fungi Ganoderma lucidum was assessed by single cell gel electrophoresis (comet assay). Human lymphocytes were exposed to 0, 1, 2 and 4 Gy gamma radiation in the presence and absence of BG. The comet parameters were reduced by BG. The results indicate that the BG of G. lucidum possessed significant radioprotective activity with DNA repairing ability and antioxidant activity as the suggestive mechanism. The findings suggest the potential use of this mushroom for the prevention of radiation induced cellular damages.

Modulation of differentiation and self-renewal of tissue specific stem cells for effective mitigation of radiation injury

International Nuclear Information System (INIS)

Bandekar, Mayuri; Patwardhan, R.S.; Maurya, Dharmendra K.; Bhilwade, Hari N.; Sharma, Deepak; Sandur, Santosh Kumar

2017-01-01

The use of stem cells in regenerative medicine for the treatment of various human diseases is one of the active research areas. The aim of regenerative medicine is to restore normal tissue functions by replenishing injured tissues using either cell-based therapy or by inducing certain factors that can aid endogenous repair and regeneration. The approach for inducing endogenous repair and regeneration requires in vivo modulation of tissue-specific stem cells by therapeutic agents and enhance their abundance through activation, proliferation, differentiation, or reprogramming. Here we describe three different approaches to enhance the abundance of hematopoietic stem cells in vivo for mitigation of radiation induced toxicity. Baicalein, a flavonoid derived from Chinese and Indian medicinal plants like Scutellaria baicalensis and Terminalia ariuna enhanced the abundance of hematopoietic stem cells through activation of Nrf-2 in the lineage negative cells. Another anti-oxidant, chlorophyllin derived from green plant pigment, chlorophyll also enhanced the abundance of hematopoietic stem cells through modulation of cell cycle in cells of the bone marrow. Treatment of mice with Cobaltus chloride (CoCl_2), a well-known activator of hypoxia inducible factor-1α (HIP-1α), also led to increase in the number of hematopoietic stem cells in the bone marrow. Whereas chlorophyllin offered up to 100 % protection against whole body irradiation (WBI, 8 Gy) induced mortality in mice, baicalein offered up to70%protection. Cobaltus chloride treatment offered 40% protection against 8 Gy of WBI. These studies indicate potential use of stem cell modulating agents as effective mitigators of radiation induced toxicity in vivo. (author)

Detection of heavy ion induced DNA double-strand breaks using static-field gel electrophoresis

International Nuclear Information System (INIS)

Taucher-Scholz, G.; Heilmann, J.; Schneider, G.; Kraft, G.

1994-11-01

Radiation induced DNA double-strand breaks (DSBs) were measured in Chinese hamster ovary cells (CHO-K1) using an experimental protocol involving static-field gel electrophoresis following exposure to various accelerated ions. Dose-effect curves were set up and relative biological efficiencies (RBEs) for DSB induction were determined for different radiation qualities. RBEs around 1 were obtained for low energy deuterons (6-7 keV/μm), while for high energy oxygen ions (20 keV/μm) an RBE value slightly greater than 1 was determined. Low energetic oxygen ions (LET ∼ 250 keV/μm) were found to show RBEs substantially below unity, and for higher LET particles (≥ 250 keV/μm) RBEs for DSB induction were generally found to be smaller than 1. The data presented here are in line with the generally accepted view that not induced DSBs, but misrepaired or unrepaired DNA-lesions are related to cellular inactivation. (orig.)

Radiation Synthesis of PEGDA and Acrylated Palm Oil Nanosized Gel for Bioactives Immobilization

International Nuclear Information System (INIS)

Hamzah, M.Y.; Tajau, R.; Dahlan, K.Z. Mohd; Mahmood, M.H.; Hashim, K.

2010-01-01

The use of microemulsion in the development of nanosized gel based on polyethylene glycol diacrylate (PEGDA) and acrylated palm oil (APO) is demonstrated. PEGDA was solubilized in n-heptane with use of AOT at 0.15M concentration to form reverse micelles, while APO was solubilized with SDS in water to form direct micelles. Both of these systems were depicted by means of ternary phase diagram. These micelles were than irradiated at 1,3,5,10,15 and 30kGy using gamma irradiation or EB to crosslink the entrapped polymer in the micelles. Ionizing radiation was imparted to the emulsions to generate crosslinking reactions in the micelles formed. The nanosized gel was evaluated in terms of particle diameter using dynamic light scattering and the images of the nanosized gel were studied using transmission electron microscopy (TEM). Results show that the size, charge and shape of the particles are influenced by concentration of surfactants and radiation dose. This study showed that this method can be utilized to produce nanosized gel. Future work include the attachment of functional group to the nano sized gel, loading of drug such as curcumin and further characterization using dynamic light scattering. (author)

Radiation Synthesis of PEGDA and Acrylated Palm Oil Nanosized Gel for Bioactives Immobilization

Energy Technology Data Exchange (ETDEWEB)

Hamzah, M. Y.; Tajau, R.; Dahlan, K.Z. Mohd; Mahmood, M. H.; Hashim, K., E-mail: m_yusof@nuclearmalaysia.gov.my [Makmal Nanoteknologi, Blok 64, BTS, Jafan Denghil, Agensi Nuklear Malaysia, Bangi 43000 Kajang, Selangor (Malaysia)

2010-07-01

The use of microemulsion in the development of nanosized gel based on polyethylene glycol diacrylate (PEGDA) and acrylated palm oil (APO) is demonstrated. PEGDA was solubilized in n-heptane with use of AOT at 0.15M concentration to form reverse micelles, while APO was solubilized with SDS in water to form direct micelles. Both of these systems were depicted by means of ternary phase diagram. These micelles were than irradiated at 1,3,5,10,15 and 30kGy using gamma irradiation or EB to crosslink the entrapped polymer in the micelles. Ionizing radiation was imparted to the emulsions to generate crosslinking reactions in the micelles formed. The nanosized gel was evaluated in terms of particle diameter using dynamic light scattering and the images of the nanosized gel were studied using transmission electron microscopy (TEM). Results show that the size, charge and shape of the particles are influenced by concentration of surfactants and radiation dose. This study showed that this method can be utilized to produce nanosized gel. Future work include the attachment of functional group to the nano sized gel, loading of drug such as curcumin and further characterization using dynamic light scattering. (author)

Type I collagen gel protects murine fibrosarcoma L929 cells from TNFα-induced cell death

International Nuclear Information System (INIS)

Wang, Hong-Ju; He, Wen-Qi; Chen, Ling; Liu, Wei-Wei; Xu, Qian; Xia, Ming-Yu; Hayashi, Toshihiko; Fujisaki, Hitomi; Hattori, Shunji; Tashiro, Shin-ichi; Onodera, Satoshi; Ikejima, Takashi

2015-01-01

Murine fibrosarcoma L929 cells have been used to test efficacy of proinflammatory cytokine TNFα. In the present study, we reported on protective effect of type I collagen gel used as L929 cell culture. L929 cell grew and proliferated well on collagen gel. However, the L929 cells exhibited cobblestone-like morphology which was much different from the spread fusiform shape when cultured on conventional cell dishes as well as the cells tended to aggregate. On conventional cell culture dishes, the cells treated with TNFα became round in shape and eventually died in a necroptotic manner. The cells cultured on collagen gel, however, were completely unaffected. TNFα treatment was reported to induce autophagy in L929 cells on the plastic dish, and therefore we investigated the effect of collagen gel on induction of autophagy. The results indicated that autophagy induced by TNFα treatment was much reduced when the cells were cultured on collagen gel. In conclusion, type I collagen gel protected L929 cell from TNFα-induced cell death. - Highlights: • Collagen gel culture changed the morphology of L929 cells. • L929 cell cultured on collagen gel were resistant to TNFα-induced cell death. • Collagen gel culture inhibited TNFα-induced autophagy in L929 cells

Type I collagen gel protects murine fibrosarcoma L929 cells from TNFα-induced cell death

Energy Technology Data Exchange (ETDEWEB)

Wang, Hong-Ju; He, Wen-Qi; Chen, Ling; Liu, Wei-Wei; Xu, Qian; Xia, Ming-Yu; Hayashi, Toshihiko [China-Japan Research Institute of Medical and Pharmaceutical Sciences, Shenyang Pharmaceutical University, Shenyang 110016 (China); Fujisaki, Hitomi; Hattori, Shunji [Nippi Research Institute of Biomatrix, Toride, Ibaraki 302-0017 (Japan); Tashiro, Shin-ichi [Institute for Clinical and Biomedical Sciences, Kyoto 603-8072 (Japan); Onodera, Satoshi [Department of Clinical and Pharmaceutical Sciences, Showa Pharmaceutical University, Tokyo 194-8543 (Japan); Ikejima, Takashi, E-mail: ikejimat@vip.sina.com [China-Japan Research Institute of Medical and Pharmaceutical Sciences, Shenyang Pharmaceutical University, Shenyang 110016 (China)

2015-02-20

Murine fibrosarcoma L929 cells have been used to test efficacy of proinflammatory cytokine TNFα. In the present study, we reported on protective effect of type I collagen gel used as L929 cell culture. L929 cell grew and proliferated well on collagen gel. However, the L929 cells exhibited cobblestone-like morphology which was much different from the spread fusiform shape when cultured on conventional cell dishes as well as the cells tended to aggregate. On conventional cell culture dishes, the cells treated with TNFα became round in shape and eventually died in a necroptotic manner. The cells cultured on collagen gel, however, were completely unaffected. TNFα treatment was reported to induce autophagy in L929 cells on the plastic dish, and therefore we investigated the effect of collagen gel on induction of autophagy. The results indicated that autophagy induced by TNFα treatment was much reduced when the cells were cultured on collagen gel. In conclusion, type I collagen gel protected L929 cell from TNFα-induced cell death. - Highlights: • Collagen gel culture changed the morphology of L929 cells. • L929 cell cultured on collagen gel were resistant to TNFα-induced cell death. • Collagen gel culture inhibited TNFα-induced autophagy in L929 cells.

Fricke Xylenol Gel characterization at megavoltage radiation energy

Energy Technology Data Exchange (ETDEWEB)

Del Lama, Lucas Sacchini, E-mail: lucasdellama@gmail.com [Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, DF-FFCLRP/USP, Avenida Bandeirantes, n" o 3900, Monte Alegre, CEP: 14040-901, Ribeirão Preto, SP (Brazil); Petchevist, Paulo César Dias [Oncoville, Centro de Excelência em Radioterapia em Curitiba, Rodovia BR-277, n" o 1437, Ecoville, CEP: 82305-100, Curitiba, PR (Brazil); Almeida, Adelaide de [Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, DF-FFCLRP/USP, Avenida Bandeirantes, n" o 3900, Monte Alegre, CEP: 14040-901, Ribeirão Preto, SP (Brazil)

2017-03-01

Accurate determination of absorbed dose is of great importance in every medical application of ionizing radiation, mainly when involving biological tissues. Among different types of dosimeters, the ferrous sulfate chemical solution, known as Fricke solution, can be detached, due to its accuracy, reproducibility and linearity, been used in radiation dosimetry for over 50 years. Besides these characteristics, the Fricke Xylenol Gel (FXG), became one of the most known dosimeters for absorbed dose spatial distribution because of its high spatial resolution. In this work, we evaluated the FXG dosimeter taking into account different preparation recipes, in order to characterize its response in terms of absorbed dose range, linearity, sensitivity and fading.

Fricke Xylenol Gel characterization at megavoltage radiation energy

International Nuclear Information System (INIS)

o 3900, Monte Alegre, CEP: 14040-901, Ribeirão Preto, SP (Brazil))" data-affiliation=" (Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, DF-FFCLRP/USP, Avenida Bandeirantes, no 3900, Monte Alegre, CEP: 14040-901, Ribeirão Preto, SP (Brazil))" >Del Lama, Lucas Sacchini; o 1437, Ecoville, CEP: 82305-100, Curitiba, PR (Brazil))" data-affiliation=" (Oncoville, Centro de Excelência em Radioterapia em Curitiba, Rodovia BR-277, no 1437, Ecoville, CEP: 82305-100, Curitiba, PR (Brazil))" >Petchevist, Paulo César Dias; o 3900, Monte Alegre, CEP: 14040-901, Ribeirão Preto, SP (Brazil))" data-affiliation=" (Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, DF-FFCLRP/USP, Avenida Bandeirantes, no 3900, Monte Alegre, CEP: 14040-901, Ribeirão Preto, SP (Brazil))" >Almeida, Adelaide de

2017-01-01

Accurate determination of absorbed dose is of great importance in every medical application of ionizing radiation, mainly when involving biological tissues. Among different types of dosimeters, the ferrous sulfate chemical solution, known as Fricke solution, can be detached, due to its accuracy, reproducibility and linearity, been used in radiation dosimetry for over 50 years. Besides these characteristics, the Fricke Xylenol Gel (FXG), became one of the most known dosimeters for absorbed dose spatial distribution because of its high spatial resolution. In this work, we evaluated the FXG dosimeter taking into account different preparation recipes, in order to characterize its response in terms of absorbed dose range, linearity, sensitivity and fading.

Application of controlled radiation-induced degradation in polymers: less exploited aspect of radiation processing of polymers

International Nuclear Information System (INIS)

Haji Saeid, M.; Guven, O.

2007-01-01

Industrial use of ionizing radiation treatment has been most successful in applications related to polymeric materials. The polymer, plastics and rubber industries have benefited from the unique advantages of ionizing radiation since its inception as an industrial tool to modify their properties and manufacture novel materials with value addition to the end product. The established and emerging applications of electron beam processing of polymers are based on the well known ultimate effects of ionizing radiation on polymers namely, crosslinking, curing, grafting and chain scissioning. Radiation-induced crosslinking dominates most applications, whereas the chain scissioning effect is much less explored and currently limited to radiation-induced degradation of Teflon, cellulose and polypropylene. The controlling of radiation-induced degradation for achieving a target average molecular weight or distribution has been evaluated for some polysaccharides, biopolymers and waste inner tubes whereas mitigation of the degradative effects of radiation has been analyzed from the point of view of using certain stabilizers, copolymers and annealing at an appropriate temperature. Several new or highly specialized techniques such as positron annihilation lifetime spectroscopy. Rutherford backscattering, elastic recoil detection analysis and solid waste NMR spectroscopy and gas chromatography-mass spectroscopy have been applied to the study or radiation-induced degradation. New information has been collected on the morphological changes associated with radiation-induced degradation processes, including chain scission, oxidation and free volume alteration. The IAEA coordinated research project (CRP) on Controlling of Degradation Effects in Radiation Processing of Polymers dealt with the role and importance of using ionizing radiation in controlling properties of natural and synthetic polymers through its degradative effect. This paper provides a summary of most important results

Investigation of Lithium Metal Hydride Materials for Mitigation of Deep Space Radiation

Science.gov (United States)

Rojdev, Kristina; Atwell, William

2016-01-01

Radiation exposure to crew, electronics, and non-metallic materials is one of many concerns with long-term, deep space travel. Mitigating this exposure is approached via a multi-faceted methodology focusing on multi-functional materials, vehicle configuration, and operational or mission constraints. In this set of research, we are focusing on new multi-functional materials that may have advantages over traditional shielding materials, such as polyethylene. Metal hydride materials are of particular interest for deep space radiation shielding due to their ability to store hydrogen, a low-Z material known to be an excellent radiation mitigator and a potential fuel source. We have previously investigated 41 different metal hydrides for their radiation mitigation potential. Of these metal hydrides, we found a set of lithium hydrides to be of particular interest due to their excellent shielding of galactic cosmic radiation. Given these results, we will continue our investigation of lithium hydrides by expanding our data set to include dose equivalent and to further understand why these materials outperformed polyethylene in a heavy ion environment. For this study, we used HZETRN 2010, a one-dimensional transport code developed by NASA Langley Research Center, to simulate radiation transport through the lithium hydrides. We focused on the 1977 solar minimum Galactic Cosmic Radiation environment and thicknesses of 1, 5, 10, 20, 30, 50, and 100 g/cm2 to stay consistent with our previous studies. The details of this work and the subsequent results will be discussed in this paper.

Mitigating effects of L-selenomethionine on low-dose iron ion radiation-induced changes in gene expression associated with cellular stress.

Science.gov (United States)

Nuth, Manunya; Kennedy, Ann R

2013-07-01

Ionizing radiation associated with highly energetic and charged heavy (HZE) particles poses a danger to astronauts during space travel. The aim of the present study was to evaluate the patterns of gene expression associated with cellular exposure to low-dose iron ion irradiation, in the presence and absence of L-selenomethionine (SeM). Human thyroid epithelial cells (HTori-3) were exposed to low-dose iron ion (1 GeV/n) irradiation at 10 or 20 cGy with or without SeM pretreatment. The cells were harvested 6 and 16 h post-irradiation and analyzed by the Affymetrix U133Av2 gene chip arrays. Genes exhibiting a 1.5-fold expression cut-off and 5% false discovery rate (FDR) were considered statistically significant and subsequently analyzed using the Database for Annotation, Visualization and Integrated Discovery (DAVID) for pathway analysis. Representative genes were further validated by real-time RT-PCR. Even at low doses of radiation from iron ions, global genome profiling of the irradiated cells revealed the upregulation of genes associated with the activation of stress-related signaling pathways (ubiquitin-mediated proteolysis, p53 signaling, cell cycle and apoptosis), which occurred in a dose-dependent manner. A 24-h pretreatment with SeM was shown to reduce the radiation effects by mitigating stress-related signaling pathways and downregulating certain genes associated with cell adhesion. The mechanism by which SeM prevents radiation-induced transformation in vitro may involve the suppression of the expression of genes associated with stress-related signaling and certain cell adhesion events.

Butyrate down regulates BCL-XL and sensitizes human fibroblasts to radiation and chemotherapy induced apoptosis

International Nuclear Information System (INIS)

Chung, Diana H.; Ljungman, Mats; Zhang Fenfen; Chen Feng; McLaughlin, William P.

1997-01-01

Purpose/Objective: Butyrate is a short chain fatty acid that has been implicated in the induction of cell cycle arrest, cell differentiation and apoptosis. The purpose of this study was to determine if butyrate treatment sensitizes cells to radiation or chemotherapy induced apoptosis. Materials and Methods: Normal neonatal human diploid fibroblasts were used throughout this study. Apoptosis was scored and quantified using three different methods. First, cell morphology using propidium iodide and fluorescence microscopy was used to qualitatively determine apoptosis and to quantify the percentage of cells undergoing apoptosis. Second, apoptosis induced DNA degradation was scored by quantifying the amount of cells appearing in a sub-G1 peak using fixed and PI-stained cells and flow cytometry. Third, apoptosis-induced DNA degradation was examined by using an assay involving direct lysis of cells in the wells of agarose gels followed by conventional gel electrophoresis. Western blotting was used to quantify the cellular levels of the apoptosis regulators, Bcl-2, Bcl-XL and Bax. Results: Human diploid fibroblasts, which were resistant to radiation induced apoptosis, were found to undergo massive apoptosis when radiation was combined with butyrate treatment. Sensitization was obtained when butyrate was added before or after radiation although the combination of both pre and post-treatment was the most effective. Butyrate was also found to enhance UV light and cisplatin-induced apoptosis. These findings correlated with a reduction of the apoptosis antagonist Bcl-XL. Bcl-XL levels significantly dropped in a time and dose dependent manner. In addition, butyrate effectively blocked UV-induced accumulation of p53. Conclusion: Our results suggest that butyrate may be an attractive agent to use in combination with radiation or chemotherapy to lower the apoptotic threshold of tumor cells, regardless of the p53 status of the tumor cells

Polymer gel dosimetry

Energy Technology Data Exchange (ETDEWEB)

Baldock, C [Institute of Medical Physics, School of Physics, University of Sydney (Australia); De Deene, Y [Radiotherapy and Nuclear Medicine, Ghent University Hospital (Belgium); Doran, S [CRUK Clinical Magnetic Resonance Research Group, Institute of Cancer Research, Surrey (United Kingdom); Ibbott, G [Radiation Physics, UT M D Anderson Cancer Center, Houston, TX (United States); Jirasek, A [Department of Physics and Astronomy, University of Victoria, Victoria, BC (Canada); Lepage, M [Centre d' imagerie moleculaire de Sherbrooke, Departement de medecine nucleaire et de radiobiologie, Universite de Sherbrooke, Sherbrooke, QC (Canada); McAuley, K B [Department of Chemical Engineering, Queen' s University, Kingston, ON (Canada); Oldham, M [Department of Radiation Oncology, Duke University Medical Center, Durham, NC (United States); Schreiner, L J [Cancer Centre of South Eastern Ontario, Kingston, ON (Canada)], E-mail: c.baldock@physics.usyd.edu.au, E-mail: yves.dedeene@ugent.be

2010-03-07

Polymer gel dosimeters are fabricated from radiation sensitive chemicals which, upon irradiation, polymerize as a function of the absorbed radiation dose. These gel dosimeters, with the capacity to uniquely record the radiation dose distribution in three-dimensions (3D), have specific advantages when compared to one-dimensional dosimeters, such as ion chambers, and two-dimensional dosimeters, such as film. These advantages are particularly significant in dosimetry situations where steep dose gradients exist such as in intensity-modulated radiation therapy (IMRT) and stereotactic radiosurgery. Polymer gel dosimeters also have specific advantages for brachytherapy dosimetry. Potential dosimetry applications include those for low-energy x-rays, high-linear energy transfer (LET) and proton therapy, radionuclide and boron capture neutron therapy dosimetries. These 3D dosimeters are radiologically soft-tissue equivalent with properties that may be modified depending on the application. The 3D radiation dose distribution in polymer gel dosimeters may be imaged using magnetic resonance imaging (MRI), optical-computerized tomography (optical-CT), x-ray CT or ultrasound. The fundamental science underpinning polymer gel dosimetry is reviewed along with the various evaluation techniques. Clinical dosimetry applications of polymer gel dosimetry are also presented. (topical review)

Radiation effects in polyolefins below the gel point as measured by torque rheometry

International Nuclear Information System (INIS)

Markovic, V.; Babic, D.; Silverman, J.

1981-01-01

Torque rheometry is used to obtain information about radiation effects on polymers (crosslinking, degradation) below the gel point. It is shown that rheometric melt viscosity measurements at different shear rates are related changes in the relaxation spectrum. In particular there is a significant radiation effect on low shear rate viscosities but a negligible effect on high shear rate viscosities. The fact that the shear rate in the torque rheometer oscillates about a mean value is utilized to relate torque amplitude measurements to entanglements at zero dose and to crosslink density at absorbed doses below or close to the gel point. (author)

Mammalian Target of Rapamycin Inhibition With Rapamycin Mitigates Radiation-Induced Pulmonary Fibrosis in a Murine Model

Energy Technology Data Exchange (ETDEWEB)

Chung, Eun Joo [Radiation Oncology Branch, Center for Cancer Research, National Institutes of Health, Bethesda, Maryland (United States); Sowers, Anastasia; Thetford, Angela [Radiation Biology Branch, Center for Cancer Research, National Institutes of Health, Bethesda, Maryland (United States); McKay-Corkum, Grace; Chung, Su I. [Radiation Oncology Branch, Center for Cancer Research, National Institutes of Health, Bethesda, Maryland (United States); Mitchell, James B. [Radiation Biology Branch, Center for Cancer Research, National Institutes of Health, Bethesda, Maryland (United States); Citrin, Deborah E., E-mail: citrind@mail.nih.gov [Radiation Oncology Branch, Center for Cancer Research, National Institutes of Health, Bethesda, Maryland (United States)

2016-11-15

Purpose: Radiation-induced pulmonary fibrosis (RIPF) is a late toxicity of therapeutic radiation. Signaling of the mammalian target of rapamycin drives several processes implicated in RIPF, including inflammatory cytokine production, fibroblast proliferation, and epithelial senescence. We sought to determine if mammalian target of rapamycin inhibition with rapamycin would mitigate RIPF. Methods and Materials: C57BL/6NCr mice received a diet formulated with rapamycin (14 mg/kg food) or a control diet 2 days before and continuing for 16 weeks after exposure to 5 daily fractions of 6 Gy of thoracic irradiation. Fibrosis was assessed with Masson trichrome staining and hydroxyproline assay. Cytokine expression was evaluated by quantitative real-time polymerase chain reaction. Senescence was assessed by staining for β-galactosidase activity. Results: Administration of rapamycin extended the median survival of irradiated mice compared with the control diet from 116 days to 156 days (P=.006, log-rank test). Treatment with rapamycin reduced hydroxyproline content compared with the control diet (irradiation plus vehicle, 45.9 ± 11.8 μg per lung; irradiation plus rapamycin, 21.4 ± 6.0 μg per lung; P=.001) and reduced visible fibrotic foci. Rapamycin treatment attenuated interleukin 1β and transforming growth factor β induction in irradiated lungs compared with the control diet. Type II pneumocyte senescence after irradiation was reduced with rapamycin treatment at 16 weeks (3-fold reduction at 16 weeks, P<.001). Conclusions: Rapamycin protected against RIPF in a murine model. Rapamycin treatment reduced inflammatory cytokine expression, extracellular matrix production, and senescence in type II pneumocytes.

Modulation of radiation-induced apoptosis and G2/M block in murine T-lymphoma cells

International Nuclear Information System (INIS)

Palayoor, S.T.; Macklis, R.M.; Bump, E.A.; Coleman, C.N.

1995-01-01

Radiation-induced apoptosis in lymphocyte-derived cell lines is characterized by endonucleolytic cleavage of cellular DNA within hours after radiation exposure. We have studied this phenomenon qualitatively (DNA gel electrophoresis) and quantitatively (diphenylamine reagent assay) in murine EL4 T-lymphoma cells exposed to 137 Cs γ irradiation. Fragmentation was discernible within 18-24 h after exposure. It increased with time and dose and reached a plateau after 8 Gy of γ radiation. We studied the effect of several pharmacological agents on the radiation-induced G 2 /M block and DNA fragmentation. The agents which reduced the radiation-induced G 2 /M-phase arrest (caffeine, theobromine, theophylline and 2-aminopurine) enhanced the degree of DNA fragmentation at 24 h. In contrast, the agents which sustained the radiation-induced G 2 /M-phase arrest (TPA, DBcAMP, IBMX and 3-aminobenzamide) inhibited the DNA fragmentation at 24 h. These studies on EL4 lymphoma cells are consistent with the hypothesis that cells with radiation-induced genetic damage are eliminated by apoptosis subsequent to a G 2 /M block. Furthermore, it may be possible to modulate the process of radiation-induced apoptosis in lymphoma cells with pharmacological agents that modify the radiation-induced G 2 /M block, and to use this effect in the treatment of patients with malignant disease. 59 refs., 7 figs

Protective effects of acemannan against radiation induced damage in Swiss albino mice

International Nuclear Information System (INIS)

Kumar, Sumit; Tiku, Ashu Bhan

2013-01-01

Aloe vera is one of the well known medicinal plant and posses a large no. of beneficial bioactive components like Anthraquinone, C-glycosides, anthrones, emodin, acemannan etc. Acemannan (poly-acetylated mannose) is one of the active component present in aloe vera gel and has anticancerous and antimicrobial properties. It has also been reported to have wound healing properties and has role as immunomodulator. The objective of the present study was to evaluate protective efficacy of acemannan against radiation induced damage in in-vitro and in in-vivo using murine splenocytes and Swiss albino mice as a model system. In vitro studies were done using primary mouse splenocytes cultures and effect of radiation on cell proliferation, viability, ROS, DNA damage and apoptosis were studies using MTT, trypan blue, DCFDA, single cell gel electrophoresis and ladder assay respectively. For in-vivo studies mice were pretreated with different doses of drug for 7 days followed by irradiation (5 Gy). Twenty four hours post-irradiation mice was sacrificed to observe the activity of antioxidant enzymes and level of protein expression. Acemannan showed a significant induction of proliferation of splenocytes in radiation treated groups both in in-vitro and in in-vivo. Beside a decrease in radiation induced ROS and DNA damage was observed in in-vitro system. Acemannan treatment was able to reduce the radiation induced apoptosis by about 50% both in in-vitro and in in-vivo. In in-vivo acemannan helps in the restoration of the antioxidant enzyme level (catalase, SOD, DTD and GST) besides maintaining the proper redox status via GSH, in irradiated mice. In our studies a dose of 50 mg/kg body wt of acemannan showed the best protective effects. On the basis of the above results it could be concluded that acemannan may have radioprotective potential. (author)

Rheological behaviour of white pepper gels - a new method for studying the effect of irradiation

International Nuclear Information System (INIS)

Esteves, M. Paula; Raymundo, Anabela; Sousa, Isabel de; Andrade, M. Eduarda; Empis, Jose

2002-01-01

Ground white pepper was treated by gamma radiation at average doses of 5, 10 and 15 kGy and the alterations in the rheological properties of its aqueous suspensions were used to study the radiation effects. Amylose and amylopectin suspensions were used as model systems. Ground pepper gels presented decreased strength expressed by a decrease of G' and G'' values and smaller limiting viscosity (η 0 ), as the irradiation dose increased. A similar behaviour was shown by the amylopectin gels. For the amylose gels, in opposition, irradiation induced a higher level of gel structure

Mechanism of radiation-induced degradation of poly(methyl methacrylate)

International Nuclear Information System (INIS)

Ichikawa, Tsuneki; Oyama, Ken-ichi; Yoshida, Hiroshi

1995-01-01

ESR and gel permeation chromatographic measurements of poly(methyl methacrylate) γ-irradiated between 77 K and 300 K have been carried out to elucidate the mechanism of radiation-induced degradation of the polymer. It is revealed that the scission of the main chain is not taken place immediately after the absorption of radiation energy but is induced by the intramolecular radical conversion of the side-chain -COOCH 2 radical to the tertiary -CH 2 -C(CH 3 )- radical followed by the main-chain β-scission of the latter radical. The degradation is not taken place below 190 K, because the side-chain radical starts to convert only above 190 K. The residual monomer in the polymer reacts with the side-chain radical below 190 K to generate the stable propagating-type radical, so that the degradation is suppressed even after warming the polymer to the ambient temperature. (author)

Effect of the crystallinity in the Tl signal induced by the gamma radiation in Al2O3: Eu obtained by the sol gel method

International Nuclear Information System (INIS)

Mendoza A, D.; Gonzalez M, P.R.; Custodio, E.; Rubio, E.; Rodriguez L, V.

2004-01-01

In this work the synthesis and characterization process of Al 2 O 3 and Al 2 O 3 : Eu by sol gel method is reported. A previous thermal treatment at 500 and 1000 C on the material powder type showed a notable influences on the thermoluminescent signal induced by the gamma radiation, such that the intensity thermoluminescent signal produced by samples with thermal treatment at 1000 C is much bigger that thermoluminescent signal produced by samples thermal treatment at 500 C. In order to explain this behavior, an analysis for X-ray diffraction and electron microscopy was also realized. The results show a notably influence of the crystalline array and the microstructure on the thermoluminescent behavior of the alumina. (Author)

Syneresis of rennet-induced milk gels as influenced by cheesemaking parameters

NARCIS (Netherlands)

Bijgaart, van den H.J.C.M.

1988-01-01

The syneresis behaviour of rennet-induced skimmilk gels was studied at closely controlled conditions. The origin of the endogenous syneresis pressure and changes therein and in the permeability of the gel during syneresis are discussed. The latter appears to be of predominant importance for

Influence of temperature in TL signal induced by gamma radiation in zircon prepared by sol gel via; Influencia de la temperatura en la senal TL inducida por la radiacion gamma en zirconia preparada via solgel

Energy Technology Data Exchange (ETDEWEB)

Salas, P.; Castano, V.M. [Instituto de Fisica, UNAM, Laboratorio Juriquilla, A.P. 1-1010, 76001 Queretaro (Mexico); Mendoza A, D.; Gonzalez M, P.R. [ININ, Mexico, D.F. (Mexico); Rosa C, E. de la [Centro de Investigaciones en Optical, Leon, Gto. (Mexico)

2000-07-01

In this work, it was realized a study of the temperature effects in thermoluminescent signal (Tl) induced by gamma radiation in zircon, which was prepared by the sol gel method. According to the obtained results, the zircon thermically treated at 500 C or over is sensitive to radiation. This sensitivity is increased when the temperature in study is augmented, moreover, the Tl spectra form also is modified with the temperature increment. The samples thermically treated at 750 C or over present a linear response in the dose interval 27 to 165 Gy; therefore, such materials result promissories for dosimetric purposes. (Author)

Modulation of radiation-induced apoptosis and G{sub 2}/M block in murine T-lymphoma cells

Energy Technology Data Exchange (ETDEWEB)

Palayoor, S.T.; Macklis, R.M.; Bump, E.A.; Coleman, C.N. [Harvard Medical School, Boston, MA (United States)

1995-03-01

Radiation-induced apoptosis in lymphocyte-derived cell lines is characterized by endonucleolytic cleavage of cellular DNA within hours after radiation exposure. We have studied this phenomenon qualitatively (DNA gel electrophoresis) and quantitatively (diphenylamine reagent assay) in murine EL4 T-lymphoma cells exposed to {sup 137}Cs {gamma} irradiation. Fragmentation was discernible within 18-24 h after exposure. It increased with time and dose and reached a plateau after 8 Gy of {gamma} radiation. We studied the effect of several pharmacological agents on the radiation-induced G{sub 2}/M block and DNA fragmentation. The agents which reduced the radiation-induced G{sub 2}/M-phase arrest (caffeine, theobromine, theophylline and 2-aminopurine) enhanced the degree of DNA fragmentation at 24 h. In contrast, the agents which sustained the radiation-induced G{sub 2}/M-phase arrest (TPA, DBcAMP, IBMX and 3-aminobenzamide) inhibited the DNA fragmentation at 24 h. These studies on EL4 lymphoma cells are consistent with the hypothesis that cells with radiation-induced genetic damage are eliminated by apoptosis subsequent to a G{sub 2}/M block. Furthermore, it may be possible to modulate the process of radiation-induced apoptosis in lymphoma cells with pharmacological agents that modify the radiation-induced G{sub 2}/M block, and to use this effect in the treatment of patients with malignant disease. 59 refs., 7 figs.

Bimodal cell death induced by high radiation doses in the radioresistant sf9 insect cell line

International Nuclear Information System (INIS)

Chandna, S.

2003-01-01

Full text: This study was conducted to investigate the mode(s) of cell death induced by high radiation doses in the highly radioresistant Sf9 insect ovarian cell line. Methods: Cells were exposed to γ-radiation doses 200Gy and 500Gy, harvested at various time intervals (6h-72h) following irradiation, and subjected to cell morphology assay, DNA agarose gel electrophoresis, single cell gel electrophoresis (SCGE; comet assay) and Annexin-V labeling for the detection of membrane phosphatidylserine externalization. Cell morphology was assessed in cells entrapped and fixed in agarose gel directly from the cell suspension, thus preventing the possible loss of fragments/ apoptotic bodies. Surviving fraction of Sf9 cells was 0.01 at 200Gy and 98%) undergoing extensive DNA fragmentation at 500Gy, whereas the frequency of cells with DNA fragmentation was considerably less (∼12%) at 200Gy. Conclusions: While the mode of cell death at 200Gy seems to be different from typical apoptosis, a dose of 500Gy induced bimodal cell death, with typical apoptotic as well as the atypical cell death observed at 200Gy

Dose of radiation enhancement, using silver nanoparticles in a human tissue equivalent gel dosimeter.

Science.gov (United States)

Hassan, Muhammad; Waheed, Muhammad Mohsin; Anjum, Muhammad Naeem

2016-01-01

To quantify the radiation dose enhancement in a human tissue-equivalent polymer gel impregnated with silver nanoparticles. The case-control study was conducted at the Bahawalpur Institute of Nuclear Medicine and Oncology, Bahawalpur, Pakistan, in January 2014. Silver nanoparticles used in this study were prepared by wet chemical method. Polymer gel was prepared by known quantity of gelatine, methacrylic acid, ascorbic acid, copper sulphate pentahydrate, hydroquinone and water. Different concentrations of silver nanoparticles were added to the gel during its cooling process. The gel was cooled in six plastic vials of 50ml each. Two vials were used as a control sample while four vials were impregnated with silver nanoparticles. After 22 hours, the vials were irradiated with gamma rays by aCobalt-60 unit. Radiation enhancement was assessed by taking magnetic resonance images of the vials. The images were analysed using Image J software. The dose enhancement factor was 24.17% and 40.49% for 5Gy and 10Gy dose respectively. The dose enhancement factor for the gel impregnated with 0.10mM silver nanoparticles was 32.88% and 51.98% for 5Gy and 10Gy dose respectively. The impregnation of a tissue-equivalent gel with silver nanoparticles resulted in dose enhancement and this effect was magnified up to a certain level with the increase in concentration of silver nanoparticles.

Proteomic analysis of PC12 cell differentiation induced by ionizing radiation

International Nuclear Information System (INIS)

Zhang Junquan; Gao Ronglian; Chen Xiaohua; Wang Zhidong; Dong Bo; Rao Yalan; Hou Lili; Zhang Hao; Mao Bingzhi

2005-01-01

Objective: To explore the molecular mechanism of PC12 cell differentiation induced by ionizing radiation and screen the molecular target of nervous system injured by irradiation. Methods: PC12 cells were irradiated with 16 Gy 60 Co γ ray. Total proteins of normal and irradiated cells were prepared 48 hours after irradiation and separated with two dimensional gel electrophoresis. Some differential expressed proteins were characterized with mass spectrometry. Results: 876 differential expressed proteins were observed. Up-regulated expression of ubiquitin carboxyl-terminal hydratase L1 was found. Down-regulated expression of new protein similar to HP1α was found. Conclusion: The characterization of some differential expressed proteins through proteomic analysis would benefit the research of molecular mechanism of PC12 cell differentiation induced by ionizing radiation. (authors)

Two Strategies for the Development of Mitochondrion-Targeted Small Molecule Radiation Damage Mitigators

International Nuclear Information System (INIS)

Rwigema, Jean-Claude M.; Beck, Barbara; Wang Wei; Doemling, Alexander; Epperly, Michael W.; Shields, Donna; Goff, Julie P.; Franicola, Darcy; Dixon, Tracy; Frantz, Marie-Celine; Wipf, Peter; Tyurina, Yulia; Kagan, Valerian E.; Wang, Hong

2011-01-01

Purpose: To evaluate the effectiveness of mitigation of acute ionizing radiation damage by mitochondrion-targeted small molecules. Methods and Materials: We evaluated the ability of nitroxide-linked alkene peptide isostere JP4-039, the nitric oxide synthase inhibitor-linked alkene peptide esostere MCF201-89, and the p53/mdm2/mdm4 protein complex inhibitor BEB55 to mitigate radiation effects by clonogenic survival curves with the murine hematopoietic progenitor cell line 32D cl 3 and the human bone marrow stromal (KM101) and pulmonary epithelial (IB3) cell lines. The p53-dependent mechanism of action was tested with p53 +/+ and p53 -/- murine bone marrow stromal cell lines. C57BL/6 NHsd female mice were injected i.p. with JP4-039, MCF201-89, or BEB55 individually or in combination, after receiving 9.5 Gy total body irradiation (TBI). Results: Each drug, JP4-039, MCF201-89, or BEB55, individually or as a mixture of all three compounds increased the survival of 32D cl 3 (p = 0.0021, p = 0.0011, p = 0.0038, and p = 0.0073, respectively) and IB3 cells (p = 0.0193, p = 0.0452, p = 0.0017, and p = 0.0019, respectively) significantly relative to that of control irradiated cells. KM101 cells were protected by individual drugs (p = 0.0007, p = 0.0235, p = 0.0044, respectively). JP4-039 and MCF201-89 increased irradiation survival of both p53 +/+ (p = 0.0396 and p = 0.0071, respectively) and p53 -/- cells (p = 0.0007 and p = 0.0188, respectively), while BEB55 was ineffective with p53 -/- cells. Drugs administered individually or as a mixtures of all three after TBI significantly increased mouse survival (p = 0.0234, 0.0009, 0.0052, and 0.0167, respectively). Conclusion: Mitochondrial targeting of small molecule radiation mitigators decreases irradiation-induced cell death in vitro and prolongs survival of lethally irradiated mice.

Development of Gel Polymer Electrolytes Using Radiation for Lithium Secondary Batteries

Energy Technology Data Exchange (ETDEWEB)

Park, Jung Ki; Lee, Jun Young; Lee, Dong Jin [KAIST, Daejeon (Korea, Republic of)

2010-05-15

Recently, demands of high performance lithium battery are increased. Development of battery materials for high power, high capacity, high safety are also needed. This project deals with the new gel polymer electrolyte based on the microporous matrix with specific functions using radiation techniques.

Rheological behaviour of white pepper gels - a new method for studying the effect of irradiation

Energy Technology Data Exchange (ETDEWEB)

Esteves, M. Paula E-mail: paula.esteves@ineti.pt; Raymundo, Anabela; Sousa, Isabel de; Andrade, M. Eduarda; Empis, Jose

2002-07-01

Ground white pepper was treated by gamma radiation at average doses of 5, 10 and 15 kGy and the alterations in the rheological properties of its aqueous suspensions were used to study the radiation effects. Amylose and amylopectin suspensions were used as model systems. Ground pepper gels presented decreased strength expressed by a decrease of G' and G'' values and smaller limiting viscosity ({eta}{sub 0}), as the irradiation dose increased. A similar behaviour was shown by the amylopectin gels. For the amylose gels, in opposition, irradiation induced a higher level of gel structure.

Effects of copper ions on the characteristics of egg white gel induced by strong alkali.

Science.gov (United States)

Shao, Yaoyao; Zhao, Yan; Xu, Mingsheng; Chen, Zhangyi; Wang, Shuzhen; Tu, Yonggang

2017-09-01

This study investigated the effects of copper ions on egg white (EW) gel induced by strong alkali. Changes in gel characteristics were examined through texture profile analysis, scanning electron microscopy (SEM), and chemical methods. The value of gel strength reached its maximum when 0.1% copper ions was added. However, the lowest cohesiveness values were observed at 0.1%. The springiness of gel without copper ions was significantly greater than the gel with copper ions added. SEM results illustrated that the low concentration of copper ions contributes to a dense and uniform gel network, and an open matrix was formed at 0.4%. The free and total sulphhydryl group content in the egg white protein gel significantly decreased with the increased copper. The increase of copper ions left the contents of ionic and hydrogen bonds basically unchanged, hydrophobic interaction presented an increasing trend, and the disulfide bond exhibited a completely opposite change. The change of surface hydrophobicity proved that the main binding force of copper induced gel was hydrophobic interaction. However, copper ions had no effect on the protein component of the gels. Generally, a low level of copper ions facilitates protein-protein association, which is involved in the characteristics of gels. Instead, high ionic strength had a negative effect on gels induced by strong alkali. © 2017 Poultry Science Association Inc.

A comparative study of radiation induced DNA damage and repair in buccal cells and lymphocytes assessed by single cell gel electrophoresis (comet) assay

International Nuclear Information System (INIS)

Dhillon, V.S.; Fenech, M.

2003-01-01

Full text: During the past few years, there has been increasing interest in epithelial cells from buccal mucosa for genotoxicity evaluation of different chemical and/or physical agents. In the present study we used the buccal and sublingual epithelial cells to detect both inter- and intra-individual variation in radiation induced DNA damage and repair. For this purpose we used the single cell gel electrophoresis assay which over the years has gained wide spread acceptance as a simple, sensitive and reliable assay to measure genotoxicity related effects as well as kinetics of DNA repair. Buccal and sublingual epithelial cells from six individuals (3 male and 3 females; 35-45 years old) were collected. Cells were then irradiated for 0, 2 and 4 Gy doses using 137 Cs-source (5.58 Gy min-1). After irradiation the cells were either placed immediately on ice or incubated at 37 deg C for 2 1/2 hour to allow cellular repair. We also studied G0 and G1 lymphocytes from the same individuals to compare the radiation-induced DNA damage and repair potential with the two types of buccal cells. Baseline DNA damage rate was significantly greater (p < 0.001) in buccal (28.18%) and sublingual epithelial cells (30.66) as compared to G0 (22.02%) and G1 (21.46%) lymphocytes. Radiation-induced DNA damage in buccal (19.34%, 2Gy; 21.41%, 4 Gy) and sublingual epithelial cells (18.11% and 20.60%) was very similar and significantly lower than that observed in lymphocytes (29.76%, 56.77% for G0 and 32.66%, 59.32% for G1). The extent of DNA repair in buccal and sublingual epithelial cells was significantly lower than that observed in lymphocytes. The results for buccal and sublingual epithelial cells were highly correlated with each other (r 0.9541) as were those of G0 and G1 lymphocytes (r 0.9868). The results suggest a much reduced capacity for cellular repair in buccal and sublingual epithelial cells

Effects of structural rearrangements on the rheology of rennet-induced casein particle gels

NARCIS (Netherlands)

Mellema, M.; Walstra, P.; Opheusden, van J.H.J.; Vliet, van T.

2002-01-01

During ageing of casein or skim milk gels, structural changes take place that affect gel parameters, such as pore size and storage modulus. These changes can be explained in terms of rearrangements of the gel network at various length scales. In this paper, rheological experiments on rennet-induced

Collagen gel protects L929 cells from TNFα-induced death by activating NF-κB.

Science.gov (United States)

Wang, Hong-Ju; Li, Meng-Qi; Liu, Wei-Wei; Hayashi, Toshihiko; Fujisaki, Hitomi; Hattori, Shunji; Tashiro, Shin-Ichi; Onodera, Satoshi; Ikejima, Takashi

2017-09-01

Type I collagen is one of the most abundant components of extracellular matrix. We previously illustrated that murine fibrosarcoma L929 cells grew well on type I collagen gel and escaped from TNFα-induced cell death. In this study, we investigated the mechanism underlying the protective effect of collagen gel. We used western blot, confocal microscopy, MTT assay and flow cytometry by introducing fluorescence staining to determine the expression levels of nuclear factor kappa B (NF-κB), inhibitory ratio and autophagy. L929 cells on collagen gel showed higher expression of NF-κB in the nucleus. Inhibition of NF-κB with pyrrolidine dithiocarbamate hydrochloride (PDTC) or knockdown by NF-κB-siRNA canceled the protective effect of collagen gel on L929 cells from TNFα-induced death, suggesting for the role of NF-κB in the protection from cell death. We found a new aspect of the effect of PDTC on L929 cells cultured on collagen gel. PDTC alone without TNFα induced apoptosis in the L929 cells cultured on collagen gel but not the cells on plastic dish. The apoptosis induction of the L929 cells cultured on collagen gel with PDTC was repressed by inhibiting autophagy with chloroquine, an autophagy inhibitor, suggesting that autophagy contributes to the death induced by the treatment with PDTC. Possible underlying mechanism of this finding is discussed. NF-κB played an important role in protecting the L929 cells cultured on collagen gel from TNFα-induced death.

The study of polymeric hydro-gels with unique properties obtained by polymerization with gamma radiation processing

International Nuclear Information System (INIS)

Dragusin, M.

1995-01-01

This thesis presents the work carried out on polymeric hydro-gels obtained by radiation processing using 60 Co gamma rays from the irradiation facility IETI-10.000 (10 k Ci), and on the polymeric hydro-gels obtained by irradiation with the electron beams from a linear accelerator (6 MeV). The aim of the study was to determine the effect of the rate dose and total dose absorbed in the materials. There are presented the preparation methods of homo- and co-polymer hydro-gels (acrylics, namely anionic and neutral monomers (acrylamide, acrylic acid, vinyl acetate) and cationic monomers (di-methyl di-allyl ammonium chloride)) such as floculants, additives, absorbers, etc. Concerning with these we have analysed the preparation methods, the mechanical, thermal, diffusivity, and swelling properties of polymeric hydro-gels in a large variety of gels of type I or II. The technological aspects and end use were studied in connection with the characteristics of the radiation processing of these hydro-gels as a function of chemical composition rate and absorbed dose, swelling degree (low and very high hydro-soluble), mechanical and diffusional properties. (author) 33 figs., 12 tabs., 101 refs

Mechanisms of radiation-induced normal tissue toxicity and implications for future clinical trials

Energy Technology Data Exchange (ETDEWEB)

Kim, Jae Ho; Jenrow, Kenneth A.; Brown, Stephen L. [Dept.of Radiation Oncology, Henry Ford Health System, Detroit (United States)

2014-09-15

To summarize current knowledge regarding mechanisms of radiation-induced normal tissue injury and medical countermeasures available to reduce its severity. Advances in radiation delivery using megavoltage and intensity-modulated radiation therapy have permitted delivery of higher doses of radiation to well-defined tumor target tissues. Injury to critical normal tissues and organs, however, poses substantial risks in the curative treatment of cancers, especially when radiation is administered in combination with chemotherapy. The principal pathogenesis is initiated by depletion of tissue stem cells and progenitor cells and damage to vascular endothelial microvessels. Emerging concepts of radiation-induced normal tissue toxicity suggest that the recovery and repopulation of stromal stem cells remain chronically impaired by long-lived free radicals, reactive oxygen species, and pro-inflammatory cytokines/chemokines resulting in progressive damage after radiation exposure. Better understanding the mechanisms mediating interactions among excessive generation of reactive oxygen species, production of pro-inflammatory cytokines and activated macrophages, and role of bone marrow-derived progenitor and stem cells may provide novel insight on the pathogenesis of radiation-induced injury of tissues. Further understanding the molecular signaling pathways of cytokines and chemokines would reveal novel targets for protecting or mitigating radiation injury of tissues and organs.

Mechanisms of radiation-induced normal tissue toxicity and implications for future clinical trials

International Nuclear Information System (INIS)

Kim, Jae Ho; Jenrow, Kenneth A.; Brown, Stephen L.

2014-01-01

To summarize current knowledge regarding mechanisms of radiation-induced normal tissue injury and medical countermeasures available to reduce its severity. Advances in radiation delivery using megavoltage and intensity-modulated radiation therapy have permitted delivery of higher doses of radiation to well-defined tumor target tissues. Injury to critical normal tissues and organs, however, poses substantial risks in the curative treatment of cancers, especially when radiation is administered in combination with chemotherapy. The principal pathogenesis is initiated by depletion of tissue stem cells and progenitor cells and damage to vascular endothelial microvessels. Emerging concepts of radiation-induced normal tissue toxicity suggest that the recovery and repopulation of stromal stem cells remain chronically impaired by long-lived free radicals, reactive oxygen species, and pro-inflammatory cytokines/chemokines resulting in progressive damage after radiation exposure. Better understanding the mechanisms mediating interactions among excessive generation of reactive oxygen species, production of pro-inflammatory cytokines and activated macrophages, and role of bone marrow-derived progenitor and stem cells may provide novel insight on the pathogenesis of radiation-induced injury of tissues. Further understanding the molecular signaling pathways of cytokines and chemokines would reveal novel targets for protecting or mitigating radiation injury of tissues and organs.

Melatonin mitigate cerebral vasospasm after experimental subarachnoid hemorrhage: a study of synchrotron radiation angiography

Science.gov (United States)

Cai, J.; He, C.; Chen, L.; Han, T.; Huang, S.; Huang, Y.; Bai, Y.; Bao, Y.; Zhang, H.; Ling, F.

2013-06-01

Cerebral vasospasm (CV) after subarachnoid hemorrhage (SAH) is a devastating and unsolved clinical issue. In this study, the rat models, which had been induced SAH by prechiasmatic cistern injection, were treated with melatonin. Synchrotron radiation angiography (SRA) was employed to detect and evaluate CV of animal models. Neurological scoring and histological examinations were used to assess the neurological deficits and CV as well. Using SRA techniques and histological analyses, the anterior cerebral artery diameters of SAH rats with melatonin administration were larger than those without melatonin treatment (p melatonin were less than those without melatonin treatment (p melatonin could mitigate CV after experimental SAH.

Radiation-induced apoptosis in different pH environments in vitro

International Nuclear Information System (INIS)

Lee, Hyung-Sik; Park, Heon J.; Lyons, John C.; Griffin, Robert J.; Auger, Elizabeth A.; Song, Chang W.

1997-01-01

Purpose: The effect of environmental pH on the radiation-induced apoptosis in tumor cells in vitro was investigated. Methods and Materials: Mammary adenocarcinoma cells of A/J mice (SCK cells) were irradiated with γ-rays using a 137 Cs irradiator and incubated in media of different pHs. After incubation at 37 deg. C for 24-120 h the extent of apoptosis was determined using agarose gel electrophoresis, TdT-mediated dUTP-biotin nick end labeling (TUNEL) staining, flow cytometry, and release of 3 H from 3 H-thymidine labeled cells. The clonogenicity of the cells irradiated in different pH medium was determined, and the progression of cells through the cell cycle after irradiation in different pHs was also determined with flow cytometry. Results: Irradiation with 2-12 Gy of γ-rays induced apoptosis in SCK cells in pH 7.5 medium within 48 h as judged from the results of four different assays mentioned. Radiation-induced apoptosis declined as the medium pH was lowered from 7.5 to 6.4. Specifically, the radiation-induced degradation of DNA including the early DNA breaks, as determined with the TUNEL method, progressively declined as the medium pH was lowered so that little DNA fragmentation occurred 48 h after irradiation with 12 Gy in pH 6.6 medium. When the cells were irradiated and incubated for 48 h in pH 6.6 medium and the medium was replaced with pH 7.5 medium, DNA fragmentation promptly occurred. DNA fragmentation also occurred even in pH 6.6 medium when the cells were irradiated and maintained in pH 7.5 medium for 8 h or longer post-irradiation before incubation in pH 6.6 medium. The radiation-induced G 2 arrest in pH 6.6 medium lasted markedly longer than that in pH 7.5 medium. Conclusion: Radiation-induced apoptosis in SCK cells in vitro is reversibly suppressed in an acidic environment. Taking the results of four different assays together, it was concluded that early step(s) in the apoptotic pathway, probably the DNA break or upstream of DNA break, is

Assessment of DNA damage and Chromosome aberration in human lymphocyte exposed to low dose radiation detected by FISH(Fluorescence In Situ Hybridization) and SCGE(Single Cell Gel Electrophoresis)

International Nuclear Information System (INIS)

Chung, Hai Won; Kim, Su Young; Kim, Byung Mo; Kim, Sun Jin; Ha, Sung Whan; Kim, Tae Hwan; Cho, Chul Koo

2000-01-01

Comparative study was performed for the assessment of DNA damage and Chromosomal aberration in human lymphocyte exposed to low dose radiation using Fluorescence In Situ Hybridization(FISH) and Single Cell Gel Electrophoresis(SCGE). Chromosomal aberrations in human lymphocyte exposed to radiation at doses of 5, 10, 30 and 50cGy were analysed with whole chromosome-specific probes by human chromosome 1, 2 and 4 according to PAINT system. FISH with chromosome-specific probe has been used to be a valid and rapid method for detection of chromosome rearrangements induced by low dose radiation. The frequencies of stable translocation per cell equivalents were 0.0116, 0.0375, 0.0407, 0.0727 and 0.0814 for 0, 5, 10, 30 and 50cGy, respectively, and those of dicentric were 0.00, 0.0125, 0.174, 0.0291 and 0.0407 respectively. Radiation induced DNA damage in human lymphocyte in a dose-dependent manner at low doses from 5cGy to 50cGy, which were analysed by single Cell Gel Electrophoresis(SCGE). From above results, FISH seemed to be useful for radiation biodosimetry by which the frequencies of stable aberrations in human lymphocyte can be observed more easily than by conventional method and SCGE also seemed to be sensitive method for detecting DNA damage by low dose radiation exposure, so that those methods will improve our technique to perform meaningful biodosimetry for radiation at low doses

Radiation-induced apoptosis

International Nuclear Information System (INIS)

Ohyama, Harumi

1995-01-01

Apoptosis is an active process of gene-directed cellular self-destruction that can be induced in many cell types via numerous physiological and pathological stimuli. We found that interphasedeath of thymocytes is a typical apoptosis showing the characteristic features of apoptosis including cell shrinkage, chromatin condensation and DNA degradation. Moderate dose of radiation induces extensive apoptosis in rapidly proliferating cell population such as the epithelium of intestinal crypt. Recent reports indicate that the ultimate form of radiation-induced mitotic death in several cells is also apoptosis. One of the hallmarks of apoptosis is the enzymatic internucleosomal degradation of chromatin DNA. We identified an endonuclease responsible for the radiation-induced DNA degradation in rat thymocytes. The death-sparing effects of interrupting RNA and protein synthesis suggested a cell genetic program for apoptosis. Apoptosis of thymocytes initiated by DNA damage, such as radiation and radio mimetic substance, absolutely requires the protein of p53 cancer suppresser gene. The cell death induced by glucocorticoid, or aging, has no such requirement. Expression of oncogene bcl-2 rescues cells from the apoptosis. Massive apoptosis in radiosensitive cells induced by higher dose radiation may be fatal. It is suggested that selective apoptotic elimination of cells would play an important role for protection against carcinogenesis and malformation through removal of cells with unrepaired radiation-induced DNA damages. Data to evaluate the significance of apoptosis in the radiation risk are still poor. Further research should be done in order to clarify the roles of the cell death on the acute and late effects of irradiation. (author)

Radiation induction interaction between CuSO4 and clinical gel for use in MRI

International Nuclear Information System (INIS)

Cardoso, Gabriela P.; Soares, Sidney S.; Gontijo, Rodrigo M.G.; Batista, Adriana S.M.; Pereira, Esther Lorrayne M.

2017-01-01

The preparation of tissue or organ simulators for magnetic resonance imaging has particularities associated with the method of image acquisition. Magnetic permeability magnetization similar to human tissues should be considered, avoiding excessive heating of the samples during the submission to radiofrequency stimulation. In this work clinical gel with CuSO 4 compound in the proportions of 50 - 500 mg/ 100 ml of gel was prepared. Copper sulphate, because it is paramagnetic, is predicted as a favorer in the alignment of the magnetic spins of the mixture at the moment of the submission to the magnetic field. To promote the interaction between the materials the mixture was subjected to gamma radiation of 10, 50 and 100 kGy and studied by FTIR analyses. preparation and two weeks after was studied whit the UV dependence on the preparation and time for use. For this, the to the sulfate group was monitored since the peak between 190 nm and 350 nm is confused wit clinical gel used. The material was shown to be stable to be prepared two weeks prior to use. The effect of radiation on the mixture is discussed in terms of interaction of the radiation with the components of the composite. (author)

Mitigate the tent-induced perturbation in ignition capsules by supersonic radiation propagation

Science.gov (United States)

Dai, Zhensheng; Gu, Jianfa; Zheng, Wudi

2017-10-01

In the inertial confinement fusion (ICF) scheme, to trap the alpha particle products of the D-T reaction, the capsules needs to be imploded and compressed with high symmetry In the laser indirect drive scheme, the capsules are held at the center of high-Z hohlraums by thin membranes (tents). However, the tents are recognized as one of the most important contributors to hot spot asymmetries, areal density perturbations and reduced performance. To improve the capsule implosion performance, various alternatives such as the micro-scale rods, a larger fill-tube and a low-density foam layer around the capsule have been presented. Our simulations show that the radiation propagates supersonically in the low-density foam layer and starts to ablate the capsule before the perturbations induced by the tents reach the ablating fronts. The tent induced perturbations are remarkably weakened when they are propagating in the blow-off plasma.

Fabrication and characterization of poly(L-lactic acid) gels induced by fibrous complex crystallization with solvents

Energy Technology Data Exchange (ETDEWEB)

Matsuda, Yasuhiro [ORNL; Fukatsu, Akinobu [Shizuoka University, Hamamatsu, Japan; Wang, Yangyang [ORNL; Miyamoto, Kazuaki [Shizuoka University, Hamamatsu, Japan; Mays, Jimmy [University of Tennessee, Knoxville (UTK); Tasaka, Shigeru [Shizuoka University, Hamamatsu, Japan

2014-01-01

Complex crystal induced gelation of poly(L-lactic acid) (PLLA) solutions was studied for a series of solvents, including N,N-dimethylformamide (DMF). By cooling the solutions prepared at elevated temperatures, PLLA gels were produced in solvents that induced complex crystals ( -crystals) with PLLA. Fibrous structure of PLLA in the gel with DMF was observed by polarizing optical microscopy, field emission electron microscopy, and atomic force microscopy. Upon heating, the crystal form of PLLA in the DMF gel changed from -crystal to a-crystal, the major crystal form in common untreated PLLA films, but the morphology and high elastic modulus of the gel remained until the a-crystal dissolved at higher temperature. In addition, a solvent exchanging method was developed, which allowed PLLA gels to be prepared in other useful solvents that do not induce -crystals without losing the morphology and mechanical properties.

Effects of ionizing radiations on the optical properties of ionic copper-activated sol-gel silica glasses

Science.gov (United States)

Al Helou, Nissrine; El Hamzaoui, Hicham; Capoen, Bruno; Ouerdane, Youcef; Boukenter, Aziz; Girard, Sylvain; Bouazaoui, Mohamed

2018-01-01

Studying the impact of radiations on doped silica glasses is essential for several technological applications. Herein, bulk silica glasses, activated with various concentrations of luminescent monovalent copper (Cu+), have been prepared using the sol-gel technique. Thereafter, these glasses were subjected to X- or γ-rays irradiation at 1 MGy(SiO2) accumulated dose. The effect of these ionizing radiations on the optical properties of these glasses, as a function of the Cu-doping content, were investigated using optical absorption and photoluminescence spectroscopies. Before any irradiation, the glass with the lowest copper concentration exhibits blue and green luminescence bands under UV excitation, suggesting that Cu+ ions occupy both cubic and tetragonal symmetry sites. However, at higher Cu-doping level, only the green emission band exists. Moreover, we showed that the hydroxyl content decreases with increasing copper doping concentration. Both X and γ radiation exposures induced visible absorption due to HC1 color centers in the highly Cu-doped glasses. In the case of the lower Cu-doped glass, the Cu+ sites with a cubic symmetry are transformed into sites with tetragonal symmetry.

Preparation of poly (2-hydroxyethyl methacrylate -co-acrylamide) hydrogels by gamma radiation: sol-gel analysis, swelling kinetic and mechanical behaviour

International Nuclear Information System (INIS)

Rapado Paneque, Manuel; Concepcion Villanueva, Daniel; Peniche, Carlos; Rosiak, Janusz M.

2006-01-01

2 hydroxyethyl methacrylate (HEMA) / acrylamide (Am) hydrogels were prepared by simultaneous radiation induced cross linking copolymerization. The G values of cross linking and degradation, gelation dose and further radiation parameters were estimated by sol/gel analysis. The dynamic swelling behaviour at 37 grade centigrade of these kind of materials was studied. The influence of the absorbed dose on the swelling degree at different pH was studied. It was observed that the kinetics is in good agreement with the second order diffusion kinetics proposed by Schott. The degree of cross linking was found to increase with the adsorbed dose and influence the mechanical properties to some extend. The molar mass of chain between the network cross links was estimated

Dosimetric evaluation of spectrophotometric response of alanine gel solution for gamma, photons, electrons and thermal neutrons radiations

International Nuclear Information System (INIS)

Silva, Cleber Feijo

2009-01-01

Alanine Gel Dosimeter is a new gel material developed at IPEN that presents significant improvement on Alanine system developed by Costa. The DL-Alanine (C 3 H 7 NO 2 ) is an amino acid tissue equivalent that improves the production of ferric ions in the solution. This work aims to analyse the main dosimetric characteristics this new gel material for future application to measure dose distribution. The performance of Alanine gel solution was evaluated to gamma, photons, electrons and thermal neutrons radiations using the spectrophotometry technique. According to the obtained results for the different studied radiation types, the reproducibility intra-batches and inter-batches is better than 4% and 5%, respectively. The dose response presents a linear behavior in the studied dose range. The response dependence as a function of dose rate and incident energy is better 2% and 3%, respectively. The lower detectable dose is 0.1 Gy. The obtained results indicate that the Alanine gel dosimeter presents good performance and can be useful as an alternative dosimeter in the radiotherapy area, using MRI technique for tridimensional dose distribution evaluation. (author)

Gymnemagenin-a triterpene saponin prevents γ-radiation induced cellular DNA damage

International Nuclear Information System (INIS)

Arunachalam, Kantha Deivi; Arun, Lilly Baptista; Annamalai, Sathesh Kumar; Hari, Shanmugasundaram

2014-01-01

Gymnema sylvestre an ethno-medicinally important plant was investigated for its protecting activity against radiation induced DNA damage. The major bioactive component present in Gymnema sylvestre such as gymnemic acid and gymnemagenin a triterpene saponin, were tested for its radioprotective effects against 60 Co irradiation induced DNA damage in fish model using fresh water fish Pangasius sutchi. Fishes subjected to a dose of 133 Gy of gamma radiation and observed for eight days. The genotoxic assessment by micronucleus assay showed us that that the plant extract helped in reducing the frequency of micronucleated and binucleated erythrocytes compared to the irradiated control group. The genotoxic assessment by alkaline comet assay by single gel electrophoresis shows that pretreatment with the plant extract appreciably decreased the percentage of tail DNA towards the levels close to those of normal control group. The gradual increase in the level of the antioxidant enzymes: superoxide dismutase (SOD) and catalase (CAT) during the course of the experiment indicates that the antioxidant enzyme activities play an important role in protecting organisms against gamma radiation-induced cellular oxidative stress. In conclusion the leaf extracts of Gymnema sylvstre exerts its radio protective potential by suppressing the toxic assault of ROS generated by the ionizing radiation through its ability to boost the levels of antioxidant enzymes (CAT and SOD) due to the presence of its phytochemicals like gymnemgenenin- a Triterpene Saponin. (author)

Radiation-induced erectile dysfunction: Recent advances and future directions

Directory of Open Access Journals (Sweden)

Javed Mahmood, PhD

2016-07-01

Full Text Available Prostate cancer is one of the most prevalent cancers and the second leading cause of cancer-related deaths in men in the United States. A large number of patients undergo radiation therapy (RT as a standard care of treatment; however, RT causes erectile dysfunction (radiation-induced erectile dysfunction; RiED because of late side effects after RT that significantly affects quality of life of prostate cancer patients. Within 5 years of RT, approximately 50% of patients could develop RiED. Based on the past and current research findings and number of publications from our group, the precise mechanism of RiED is under exploration in detail. Recent investigations have shown prostate RT induces significant morphologic arterial damage with aberrant alterations in internal pudendal arterial tone. Prostatic RT also reduces motor function in the cavernous nerve which may attribute to axonal degeneration may contributing to RiED. Furthermore, the advances in radiogenomics such as radiation induced somatic mutation identification, copy number variation and genome-wide association studies has significantly facilitated identification of biomarkers that could be used to monitoring radiation-induced late toxicity and damage to the nerves; thus, genomic- and proteomic-based biomarkers could greatly improve treatment and minimize arterial tissue and nerve damage. Further, advanced technologies such as proton beam therapy that precisely target tumor and significantly reduce off-target damage to vital organs and healthy tissues. In this review, we summarize recent advances in RiED research and novel treatment modalities for RiED. We also discuss the possible molecular mechanism involved in the development of RiED in prostate cancer patients. Further, we discuss various readily available methods as well as novel strategies such as stem cell therapies, shockwave therapy, nerve grafting with tissue engineering, and nutritional supplementations might be used to

Land radiative management as contributor to regional-scale climate adaptation and mitigation

Science.gov (United States)

Seneviratne, Sonia I.; Phipps, Steven J.; Pitman, Andrew J.; Hirsch, Annette L.; Davin, Edouard L.; Donat, Markus G.; Hirschi, Martin; Lenton, Andrew; Wilhelm, Micah; Kravitz, Ben

2018-02-01

Greenhouse gas emissions urgently need to be reduced. Even with a step up in mitigation, the goal of limiting global temperature rise to well below 2 °C remains challenging. Consequences of missing these goals are substantial, especially on regional scales. Because progress in the reduction of carbon dioxide emissions has been slow, climate engineering schemes are increasingly being discussed. But global schemes remain controversial and have important shortcomings. A reduction of global mean temperature through global-scale management of solar radiation could lead to strong regional disparities and affect rainfall patterns. On the other hand, active management of land radiative effects on a regional scale represents an alternative option of climate engineering that has been little discussed. Regional land radiative management could help to counteract warming, in particular hot extremes in densely populated and important agricultural regions. Regional land radiative management also raises some ethical issues, and its efficacy would be limited in time and space, depending on crop growing periods and constraints on agricultural management. But through its more regional focus and reliance on tested techniques, regional land radiative management avoids some of the main shortcomings associated with global radiation management. We argue that albedo-related climate benefits of land management should be considered more prominently when assessing regional-scale climate adaptation and mitigation as well as ecosystem services.

Evaluation of genotoxicity of the acute gamma radiation on earthworm Eisenia fetida using single cell gel electrophoresis technique (Comet assay).

Science.gov (United States)

Sowmithra, K; Shetty, N J; Jha, S K; Chaubey, R C

2015-12-01

Earthworms (Eisenia fetida) most suitable biological indicators of radioactive pollution. Radiation-induced lesions in DNA can be considered to be molecular markers for early effects of ionizing radiation. Gamma radiation produces a wide spectrum of DNA. Some of these lesions, i.e., DNA strand breaks and alkali labile sites can be detected by the single-cell gel electrophoresis (SCGE) or comet assay by measuring the migration of DNA from immobilized nuclear DNA. E. fetida were exposed to different doses of gamma radiation, i.e., 1, 5, 10, 20, 30, 40 and 50Gy, and comet assay was performed for all the doses along with control at 1, 3 and 5h post irradiation to evaluate the genotoxicity of gamma radiation in this organism. The DNA damage was measured as percentage of comet tail DNA. A significant increase in DNA damage was observed in samples exposed to 5Gy and above, and the increase in DNA damage was dose dependent i.e., DNA damage was increased with increased doses of radiation. The highest DNA damage was noticed at 1h post irradiation and gradually decreased with time, i.e., at 3 and 5h post irradiation. The present study reveals that gamma radiation induces DNA damage in E. fetida and the comet assay is a sensitive and rapid method for its detection to detect genotoxicity of gamma radiation. Copyright © 2015 Elsevier B.V. All rights reserved.

Progress in two-dimensional polyacrylamide gel electrophoresis and application in radiation research

International Nuclear Information System (INIS)

Wang Zhidong; Chen Xiaohua

2003-01-01

Two-dimensional polyacrylamide gel electrophoresis is the key separation technique in proteomics research, which is designed by protein character: molecular weight and PI. Some progress has been made in disease mechanism detection, tumor indicator research and drug development. This technique also has some potential application in radiation research

Reduction of Radiation-Induced Changes in Biophysical Properties of Erythrocytes

International Nuclear Information System (INIS)

El-Marakby, S.M.A.

2014-01-01

group received continuous administration for two weeks before and two other weeks after irradiation (total time of administration 28 days). While the mitigation effect of poly-MVA was evaluated by its daily administration immediately after irradiation for two weeks. Measurements had been carried out include determination of cellular antioxidant enzymes (Glutathione (GSH), catalase and superoxide dismutase) and lipid peroxidation in liver homogenate. The rheological properties of blood, electrical properties, osmotic fragility and scanning electron microscope photography of erythrocytes were also performed. The electrical properties of erythrocytes suspension were measured in the frequency range 40 kHz to 5 MHz using LCR meter HIOKI 3531. The erythrocyte normal hemolysis, mean corpuscular hemoglobin concentration, mean corpuscular volume, hemoglobin concentration and hematocrit were also measured. The results showed that exposure to radiation resulted in a significant decrease in cellular antioxidant enzymes (GSH, Catalase and SOD) and decrease in the AC conductivity, relative permittivity, area under the loss curve, membrane effective capacitance, blood Bingham viscosity, yield stress and aggregation index. Furthermore it induced slightly increase in average osmotic fragility of erythrocytes accompanied by decrease in osmotic dispersion and remarkable modification of erythrocytes morphology. It also caused significant increase (75%) in the lipid peroxidation 1 day after exposure to radiation. The later change persisted until the 14th day recorded after irradiation. Oral uptake of poly-MVA showed markedly elevation in the concentration of antioxidant enzymes (GSH, Catalase and SOD), while it produced a significant decrease in blood Bingham viscosity and yield stress with a non significant change in aggregation index, accompanied by a significant increase in average osmotic hemolysis and osmotic dispersion which continued increasing with time of poly-MVA administration

Grape extract protects against γ-radiation-induced membrane damage strains of human erythrocytes

International Nuclear Information System (INIS)

Das, Subir Kumar

2017-01-01

The membrane integrity of circulating red blood cells (RBCs) is compromised by the deleterious actions of γ-radiation in humans. Grapes are the richest source of antioxidants due to presence of potentially bioactive phytochemicals. The objective of the present study was to assess the radioprotective actions of grape extracts against the γ-radiation-induced membrane permeability of human erythrocytes. The scavenging activities in seeds of grape in DPPH, hydrogen peroxide and hydroxyl radicals, were higher than skin or pulp of different cultivars. Grape extracts also showed appreciable extent of total antioxidant capacity and effective antihemolytic action. Grape extracts significantly ameliorated the γ-radiation-induced increase of the levels of thiobarbituric acid-reactive substances (TBARS, an index of lipid peroxidation) in the RBC membrane ghosts. Stored blood showed higher levels of K + ion as compared to the normal blood which was elevated by γ-radiation. Membrane ATPase was inhibited by the exposure to γ-radiation.Treatment of RBCs with the grape extracts prior to the exposure of γ-radiation significantly mitigated these changes in the erythrocyte membranes caused by the lower dose of radiation (4 Gy). (author)

Immobilization of enzymes on radiation-modified gelatine gel by using a chemical cross-linking agent

International Nuclear Information System (INIS)

Bachmann, S.; Gebicka, L.; Galant, S.

1981-01-01

Investigations into the effect of ionizing radiation on the gelatine gels have shown that water-insoluble gel can be formed under suitable irradiation conditions. To establish the optimal conditions for the processing of the insoluble gel, the yield of cross-linking has been determined for gelatine solutions and its gels irradiated with various doses in the absence and in the presence of oxygen. Glucose isomerase (GI) was used as a test enzyme for immobilization on the gelatine gel. This enzyme which catalyses the isomerization of glucose to fructose has been used on the commercial-scale production of high fructose syrups. The support matrix chosen for the enzyme immobilization has been obtained by irradiating 4% wt/vol. de-aerated gelatine gel at a dose of 1.5 x 10 4 kGy at 15 0 C. Actinoplanes missouriensis cells containing GI were mixed with gelatine gel particles and cross-linked with glutaraldehyde. It was found that the immobilized GI can be successfully applied in the continuous isomerization of glucose to fructose. (author)

Radiation-induced crosslinking of polyethylene in the presence of bifunctional vinyl monomers

Energy Technology Data Exchange (ETDEWEB)

Joshi, M.S.

1976-10-06

The apparent crosslinking produced by the radiation grafting of two monomers to polyethylene, acrylic acid and acrylonitrile, was investigated. Evidence is presented to show that covalent crosslinks are not produced during the radiation grafting step; covalent crosslinks are produced by the post-irradiation heat treatment associated with measurements of gel; the enhancement in gel fraction and physical properties arises from true crosslinks rather than chain entanglements; and there may be practical value associated with the sensitization of crosslinking produced by the methods employed in this work. The effect of monomer-solvent composition on the graft and gel yield was studied. Viscoelastic properties of grafted films were determined above the melting point of pure polyethylene. The kinetic data, infrared spectra, and viscoelastic properties are the bases for the following mechanism: (1) Acrylic acid-g-PE: Acrylic acid enters the film in the form of a hydrogen bonded dimer and undergoes a grafting reaction that produces hydrogen-bond crosslinks. The heat treatment during the conventional methods for determining of crosslinks convert them into intermolecular anhydride bonds. (2) Acrylonitrile-g-PE: In this, the post-grafting crosslinking is the result of a thermally induced chain reaction leading to an uninterrupted conjugated sequence. The length of the ring structure increases with time and temperature, and the intensity of color increases with the length of the ring structure.

Radiation-induced crosslinking of polyethylene in the presence of bifunctional vinyl monomers

International Nuclear Information System (INIS)

Joshi, M.S.

1976-01-01

The apparent crosslinking produced by the radiation grafting of two monomers to polyethylene, acrylic acid and acrylonitrile, was investigated. Evidence is presented to show that covalent crosslinks are not produced during the radiation grafting step; covalent crosslinks are produced by the post-irradiation heat treatment associated with measurements of gel; the enhancement in gel fraction and physical properties arises from true crosslinks rather than chain entanglements; and there may be practical value associated with the sensitization of crosslinking produced by the methods employed in this work. The effect of monomer-solvent composition on the graft and gel yield was studied. Viscoelastic properties of grafted films were determined above the melting point of pure polyethylene. The kinetic data, infrared spectra, and viscoelastic properties are the bases for the following mechanism: (1) Acrylic acid-g-PE: Acrylic acid enters the film in the form of a hydrogen bonded dimer and undergoes a grafting reaction that produces hydrogen-bond crosslinks. The heat treatment during the conventional methods for determining of crosslinks convert them into intermolecular anhydride bonds. (2) Acrylonitrile-g-PE: In this, the post-grafting crosslinking is the result of a thermally induced chain reaction leading to an uninterrupted conjugated sequence. The length of the ring structure increases with time and temperature, and the intensity of color increases with the length of the ring structure

Sup(1)H n.m.r. relaxation of radiation induced crosslinking in polyester-styrene systems

International Nuclear Information System (INIS)

Andreis, M.; Veksli, Z.; Ranogajec, F.; Hedvig, P.

1989-01-01

The structure and dynamics of a network formed by radiation induced crosslinking of polyesters based on 1,6-hexane diol and 1,2-propylene glycol and maleic anhydride (HDF and PGF, respectively) with styrene is studied by proton pulsed n.m.r. spectroscopy. The dependence of spin-lattice, T 1 , and spin-spin, T 2 , relaxation times on the structure of polyester chain, molar ratios of styrene to polyester unsaturations and the radiation doses are analysed in terms of network formation and structure, and their effect on molecular motion. Above the gel point, at temperatures above the glass transition, the presence of two T 2 components reflects the heterogeneity of the network structure in both resins. Parallel with the n.m.r. relaxation measurements the crosslink density was determined from the extracted gel phase or double bonds (fumaric and styrene) participating in the crosslinking process. (author)

Radiation induction interaction between CuSO{sub 4} and clinical gel for use in MRI

Energy Technology Data Exchange (ETDEWEB)

Cardoso, Gabriela P.; Soares, Sidney S.; Gontijo, Rodrigo M.G.; Batista, Adriana S.M., E-mail: sidneyss70soares@gmail.com, E-mail: gabrielapontesc@gmail.com, E-mail: rodrigogadelhagontijo1@hotmail.com [Universidade Fderal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Anatomia e Imagem; Pereira, Esther Lorrayne M., E-mail: esther_machado@outlook.com.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Engenharia Nuclear

2017-07-01

The preparation of tissue or organ simulators for magnetic resonance imaging has particularities associated with the method of image acquisition. Magnetic permeability magnetization similar to human tissues should be considered, avoiding excessive heating of the samples during the submission to radiofrequency stimulation. In this work clinical gel with CuSO{sub 4} compound in the proportions of 50 - 500 mg/ 100 ml of gel was prepared. Copper sulphate, because it is paramagnetic, is predicted as a favorer in the alignment of the magnetic spins of the mixture at the moment of the submission to the magnetic field. To promote the interaction between the materials the mixture was subjected to gamma radiation of 10, 50 and 100 kGy and studied by FTIR analyses. preparation and two weeks after was studied whit the UV dependence on the preparation and time for use. For this, the to the sulfate group was monitored since the peak between 190 nm and 350 nm is confused wit clinical gel used. The material was shown to be stable to be prepared two weeks prior to use. The effect of radiation on the mixture is discussed in terms of interaction of the radiation with the components of the composite. (author)

Clustered DNA damages induced in isolated DNA and in human cells by low doses of ionizing radiation

Science.gov (United States)

Sutherland, B. M.; Bennett, P. V.; Sidorkina, O.; Laval, J.; Lowenstein, D. I. (Principal Investigator)

2000-01-01

Clustered DNA damages-two or more closely spaced damages (strand breaks, abasic sites, or oxidized bases) on opposing strands-are suspects as critical lesions producing lethal and mutagenic effects of ionizing radiation. However, as a result of the lack of methods for measuring damage clusters induced by ionizing radiation in genomic DNA, neither the frequencies of their production by physiological doses of radiation, nor their repairability, nor their biological effects are known. On the basis of methods that we developed for quantitating damages in large DNAs, we have devised and validated a way of measuring ionizing radiation-induced clustered lesions in genomic DNA, including DNA from human cells. DNA is treated with an endonuclease that induces a single-strand cleavage at an oxidized base or abasic site. If there are two closely spaced damages on opposing strands, such cleavage will reduce the size of the DNA on a nondenaturing gel. We show that ionizing radiation does induce clustered DNA damages containing abasic sites, oxidized purines, or oxidized pyrimidines. Further, the frequency of each of these cluster classes is comparable to that of frank double-strand breaks; among all complex damages induced by ionizing radiation, double-strand breaks are only about 20%, with other clustered damage constituting some 80%. We also show that even low doses (0.1-1 Gy) of high linear energy transfer ionizing radiation induce clustered damages in human cells.

Gel entrapment culture of rat hepatocytes for investigation of tetracycline-induced toxicity

International Nuclear Information System (INIS)

Shen Chong; Meng Qin; Schmelzer, Eva; Bader, Augustinus

2009-01-01

This paper aimed to explore three-dimensionally cultured hepatocytes for testing drug-induced nonalcoholic steatohepatitis. Gel entrapped rat hepatocytes were applied for investigation of the tetracycline-induced steatohepatitis, while hepatocyte monolayer was set as a control. The toxic responses of hepatocytes were systematically evaluated by measuring cell viability, liver-specific function, lipid accumulation, oxidative stress, adenosine triphosphate content and mitochondrial membrane potential. The results suggested that gel entrapped hepatocytes showed cell death after 96 h of tetracycline treatment at 25 μM which is equivalent to toxic serum concentration in rats, while hepatocyte monolayer showed cell death at a high dose of 200 μM. The concentration-dependent accumulation of lipid as well as mitochondrial damage were regarded as two early events for tetracycline hepatotoxicity in gel entrapment culture due to their detectability ahead of subsequent increase of oxidative stress and a final cell death. Furthermore, the potent protection of fenofibrate and fructose-1,6-diphosphate were evidenced in only gel entrapment culture with higher expressions on the genes related to β-oxidation than hepatocyte monolayer, suggesting the mediation of lipid metabolism and mitochondrial damage in tetracycline toxicity. Overall, gel entrapped hepatocytes in three-dimension reflected more of the tetracycline toxicity in vivo than hepatocyte monolayer and thus was suggested as a more relevant system for evaluating steatogenic drugs.

Anti-inflammatory effect of diclofenac diethylammonium gel on acute phase of ligature induced periodontitis in rats

OpenAIRE

Botelho, Marco A.; Paixão, Mônica S.; Rachid, Ítalo; Bannet, Leonard Edward; Patrus, Ana Helena; Mattos, Thiago Borges; Queiroz, Dinalva; Ruela, Ronaldo; Costa, Jose M. C; Quintans Júnior, Lucindo José

2010-01-01

This study aimed to evaluate the effect of a diclofenac diethylammonium gel 10 mg/g (DD) on acute phase of ligature induced periodontitis model in rats. Experimental Periodontitis Disease (EPD) was induced in 30 Wistar rats subjected to ligature placement on left molars. Animals were treated with (DD), immediately after (EPD) induction. Saline-based gel (SG) was utilized as negative control and DD gel 10 mg/g was the tested substance. Animals were randomly assigned into the groups. The period...

Solvent induced supramolecular anisotropy in molecular gels

Energy Technology Data Exchange (ETDEWEB)

Rogers, Michael A., E-mail: mroger09@uoguelph.ca [Department of Food Science, University of Guelph, Guelph, Ontario, N3C3X9 (Canada); Corradini, Maria G. [Department of Food Science, University of Massachusetts Amherst, Amherst, MA, 01003 (United States); Emge, Thomas [Department of Chemistry and Biochemistry, Rutgers University, New Brunswick, NJ, 08901 (United States)

2017-06-15

Herein is the first report of solvent induced anisotropy in 12-hydroxystearic acid self-assembled fibrillar networks. Increasing the chain length of polar solvent, such as nitriles and ketones, tailored the anisotropy of the fibrillar aggregates. 12HSA molecular gels, comprised of alkanes, exhibited an isotropic fibrillar network irrespective of the alkane chain length. In polar solvents, anisotropy, observed using 2D powder x-ray diffraction profiles, is correlated to a fibrillar supramolecular morphologies in long chain nitriles and ketones while sphereulitic crystals are correlated to x-ray diffraction patterns with an isotropic scatter intensity in short chain ketones and nitriles. These changes directly modify the final physical properties of the gels. - Highlights: • 12-HSA self-assembles into crystalline supramolecular morphologies depending on the solvent. • Alkanes, short chain nitriles and ketones led to 12-HSA displaying supramolecular isotropy. • In long chain nitriles and ketones, 12-HSA displays supramolecular anisotropy.

Solvent induced supramolecular anisotropy in molecular gels

International Nuclear Information System (INIS)

Rogers, Michael A.; Corradini, Maria G.; Emge, Thomas

2017-01-01

Herein is the first report of solvent induced anisotropy in 12-hydroxystearic acid self-assembled fibrillar networks. Increasing the chain length of polar solvent, such as nitriles and ketones, tailored the anisotropy of the fibrillar aggregates. 12HSA molecular gels, comprised of alkanes, exhibited an isotropic fibrillar network irrespective of the alkane chain length. In polar solvents, anisotropy, observed using 2D powder x-ray diffraction profiles, is correlated to a fibrillar supramolecular morphologies in long chain nitriles and ketones while sphereulitic crystals are correlated to x-ray diffraction patterns with an isotropic scatter intensity in short chain ketones and nitriles. These changes directly modify the final physical properties of the gels. - Highlights: • 12-HSA self-assembles into crystalline supramolecular morphologies depending on the solvent. • Alkanes, short chain nitriles and ketones led to 12-HSA displaying supramolecular isotropy. • In long chain nitriles and ketones, 12-HSA displays supramolecular anisotropy.

Examination of Icing Induced Loss of Control and Its Mitigations

Science.gov (United States)

Reehorst, Andrew L.; Addy, Harold E., Jr.; Colantonio, Renato O.

2010-01-01

Factors external to the aircraft are often a significant causal factor in loss of control (LOC) accidents. In today s aviation world, very few accidents stem from a single cause and typically have a number of causal factors that culminate in a LOC accident. Very often the "trigger" that initiates an accident sequence is an external environment factor. In a recent NASA statistical analysis of LOC accidents, aircraft icing was shown to be the most common external environmental LOC causal factor for scheduled operations. When investigating LOC accident or incidents aircraft icing causal factors can be categorized into groups of 1) in-flight encounter with super-cooled liquid water clouds, 2) take-off with ice contamination, or 3) in-flight encounter with high concentrations of ice crystals. As with other flight hazards, icing induced LOC accidents can be prevented through avoidance, detection, and recovery mitigations. For icing hazards, avoidance can take the form of avoiding flight into icing conditions or avoiding the hazard of icing by making the aircraft tolerant to icing conditions. Icing detection mitigations can take the form of detecting icing conditions or detecting early performance degradation caused by icing. Recovery from icing induced LOC requires flight crew or automated systems capable of accounting for reduced aircraft performance and degraded control authority during the recovery maneuvers. In this report we review the icing induced LOC accident mitigations defined in a recent LOC study and for each mitigation describe a research topic required to enable or strengthen the mitigation. Many of these research topics are already included in ongoing or planned NASA icing research activities or are being addressed by members of the icing research community. These research activities are described and the status of the ongoing or planned research to address the technology needs is discussed

[Socio-psychological and ecological aspects within the system of nuclear radiation risk mitigation].

Science.gov (United States)

Davydov, B I; Ushakov, I B; Zuev, V G

2004-01-01

The authors bring into light several aspects of nuclear radiation risks, i.e. physical safety of nuclear technologies and ecology, place of operator within the nuclear radiation safety system (proficiency, protective culture, safety guides) and consider approaches to the human factor quantification within the system of mitigation of risks from nuclear technologies, and IAEA recommendations on probable risk estimation. Future investigations should be aimed at extension of the radiation sensitivity threshold, personnel selection as by psychological so genetic testing for immunity to ionizing radiation, development of pharmachemical and physical protectors and methods of enhancing nonspecific resistance to extreme, including radiation, environments, and building of radiation event simulators for training.

Drug Release Profile from Calcium-Induced Alginate-Phosphate Composite Gel Beads

Directory of Open Access Journals (Sweden)

Yoshifumi Murata

2009-01-01

Full Text Available Calcium-induced alginate-phosphate composite gel beads were prepared, and model drug release profiles were investigated in vitro. The formation of calcium phosphate in the alginate gel matrix was observed and did not affect the rheological properties of the hydrogel beads. X-ray diffraction patterns showed that the calcium phosphate does not exist in crystalline form in the matrix. The initial release amount and release rate of a water-soluble drug, diclofenac, from the alginate gel beads could be controlled by modifying the composition of the matrix with calcium phosphate. In contrast, the release profile was not affected by the modification for hydrocortisone, a drug only slightly soluble in water.

Pharmacological Protection From Radiation ± Cisplatin-Induced Oral Mucositis

International Nuclear Information System (INIS)

Cotrim, Ana P.; Yoshikawa, Masanobu; Sunshine, Abraham N.; Zheng Changyu; Sowers, Anastasia L.; Thetford, Angela D.; Cook, John A.; Mitchell, James B.; Baum, Bruce J.

2012-01-01

Purpose: To evaluate if two pharmacological agents, Tempol and D-methionine (D-met), are able to prevent oral mucositis in mice after exposure to ionizing radiation ± cisplatin. Methods and Materials: Female C3H mice, ∼8 weeks old, were irradiated with five fractionated doses ± cisplatin to induce oral mucositis (lingual ulcers). Just before irradiation and chemotherapy, mice were treated, either alone or in combination, with different doses of Tempol (by intraperitoneal [ip] injection or topically, as an oral gel) and D-met (by gavage). Thereafter, mice were sacrificed and tongues were harvested and stained with a solution of Toluidine Blue. Ulcer size and tongue epithelial thickness were measured. Results: Significant lingual ulcers resulted from 5 × 8 Gy radiation fractions, which were enhanced with cisplatin treatment. D-met provided stereospecific partial protection from lingual ulceration after radiation. Tempol, via both routes of administration, provided nearly complete protection from lingual ulceration. D-met plus a suboptimal ip dose of Tempol also provided complete protection. Conclusions: Two fairly simple pharmacological treatments were able to markedly reduce chemoradiation-induced oral mucositis in mice. This proof of concept study suggests that Tempol, alone or in combination with D-met, may be a useful and convenient way to prevent the severe oral mucositis that results from head-and-neck cancer therapy.

Radiation-induced apoptosis in differentially modulated by PTK inhibitora in K562 cells

International Nuclear Information System (INIS)

Lee, Hyung Sik; Moon, Chang Woo; Hur, Won Joo; Jeong, Su Jin; Jeong Min Ho; Lee, Jeong Hyeon; Lim, Young Jin; Park, Heon Joo

2000-01-01

The effect of PTK inhibitors (herbimycin A and genistein) on the induction of radiation-induced apoptosis in Ph-positive K562 leukemia cell line was investigated. K562 cells in exponential growth phase were irradiated with a linear accelerator at room temperature. For 6 MV X-ray irradiation and drug treatment, cultures were initiated at 2x10 6 cells/ml. The cells were irradiated with 10Gy. Stock solutions of herbimycin A and genistein were prepared in dimethyl sulphoxide (DMSO). After incubation at 37 .deg. for 0-48 h, the extent of apoptosis was determined using agarose gel electrophoresis and TUNEL assay. The progression of cells through the cell cycle after irradiation and drug treatment was also determined with flow cytometry. Western blot analysis was used to monitor bcl-2, bcl-X-L and bax protein levels. Treatment with 10 Gy X-irradiation did not result in the induction of apoptosis. The HMA alone (500 nM) also failed to induce apoptosis. By contrast, incubation of K562 cells with HMA after irradiation resulted in a substantial induction of nuclear condensation and fragmentation by agarose gel electrophoresis and TUNEL assay. Genistein failed to enhance the ability of X-irradiation to induce DNA fragmentation. Enhancement of apoptosis by HMA was not attributable to downregulation of the bcl-2 or bcl-X-L anti-apoptotic proteins. When the cells were irradiated and maintained with HMA, the percentage of cells in G2/M phase decreased to 30-40% at 48 h. On the other hand, cells exposed to 10 Gy X-irradiation alone or maintained with genistein did not show marked cell cycle redistribution. We have shown that nanomolar concentrations of the PTK inhibitor HMA synergize with X-irradiation in inducing the apoptosis in Ph (+) K562 leukemia cell line. While, genistein, a PTK inhibitor which is not selective for p210 bcr/abl failed to enhance the radiation induced apoptosis in K562 cells. It is unlikely that the ability of HMA to enhance apoptosis in K562 cells is

Effect of pH on radiation-induced apoptosis

International Nuclear Information System (INIS)

Chang, W. Song; Park, Heon J.; Lyons, John C.; Auger, Elizabeth A.; Lee, Hyung-Sik

1996-01-01

Purpose/Objective: The effect of environmental pH on the radiation-induced apoptosis in tumor cells in vitro was investigated. Materials and Methods: SCK mammary adenocarcinoma cells of A/J mice were irradiated with γ-rays using a 137 Cs irradiator and incubated in media of different pHs. After incubation at 37 degree sign C for 24-120 hrs., the extent of apoptosis was determined using agarose gel electrophoresis of DNA, in situ TUNEL staining, flow cytometry, and release of 3 H from 3 H-thymidine labeled cells. The membrane integrity, using the trypan blue exclusion method, and the clonogenicity of the cells were also determined. Results: Irradiation with 2-12 Gy of γ-rays induced apoptosis in pH 7.5 medium within 48 hrs. The radiation-induced apoptosis progressively declined as the medium pH was lowered so that little apoptosis occurred in 48 hrs. after irradiation with 12 Gy in pH 6.6 medium. However, when the cells were irradiated and incubated for 48 hrs. in pH 6.6 medium and then medium was replaced with pH 7.5 medium, apoptosis promptly occurred. Apoptosis also occurred even in pH 6.6 medium when the cells were irradiated and maintained in pH 7.5 medium for 8 hrs. or longer post-irradiation before incubation in pH 6.6 medium. Conclusion: An acidic environment markedly suppresses radiation-induced apoptosis probably by suppressing the expression of initial signals responsible for irradiation-induced apoptosis. Indications are that the signals persist in an acidic environment and trigger apoptosis when the environmental acidity is eased. Our results suggest that the acidic environment in human tumors may inhibit the apoptosis after irradiation. However, apoptosis may be triggered when reoxygenation occurs after irradiation, and thus, the intratumor environment becomes less acidic after irradiation. Not only the change in pO 2 but the change in pH during the course of fractionated radiotherapy may greatly influence the outcome of the treatment

Radiation-induced nitric oxide mitigates tumor hypoxia and radioresistance in a murine SCCVII tumor model

International Nuclear Information System (INIS)

Nagane, Masaki; Yasui, Hironobu; Yamamori, Tohru; Zhao, Songji; Kuge, Yuji; Tamaki, Nagara; Kameya, Hiromi; Nakamura, Hideo; Fujii, Hirotada; Inanami, Osamu

2013-01-01

Highlights: •IR-induced NO increased tissue perfusion and pO 2 . •IR increased NO production in tumors without changes in the mRNA and protein levels of NOS isoforms. •NOS activity assay showed that IR upregulated eNOS activity in tumors. •IR-induced NO decreased tumor hypoxia and altered tumor radiosensitivity. -- Abstract: Tumor hypoxia, which occurs mainly as a result of inadequate tissue perfusion in solid tumors, is a well-known challenge for successful radiotherapy. Recent evidence suggests that ionizing radiation (IR) upregulates nitric oxide (NO) production and that IR-induced NO has the potential to increase intratumoral circulation. However, the kinetics of NO production and the responsible isoforms for NO synthase in tumors exposed to IR remain unclear. In this study, we aimed to elucidate the mechanism by which IR stimulates NO production in tumors and the effect of IR-induced NO on tumor radiosensitivity. Hoechst33342 perfusion assay and electron spin resonance oxymetry showed that IR increased tissue perfusion and pO 2 in tumor tissue. Immunohistochemical analysis using two different hypoxic probes showed that IR decreased hypoxic regions in tumors; treatment with a nitric oxide synthase (NOS) inhibitor, L-NAME, abrogated the effects of IR. Moreover, IR increased endothelial NOS (eNOS) activity without affecting its mRNA or protein expression levels in SCCVII-transplanted tumors. Tumor growth delay assay showed that L-NAME decreased the anti-tumor effect of fractionated radiation (10 Gy × 2). These results suggested that IR increased eNOS activity and subsequent tissue perfusion in tumors. Increases in intratumoral circulation simultaneously decreased tumor hypoxia. As a result, IR-induced NO increased tumor radiosensitivity. Our study provides a new insight into the NO-dependent mechanism for efficient fractionated radiotherapy

Solvent exchange-induced in situ forming gel comprising ethyl cellulose-antimicrobial drugs.

Science.gov (United States)

Phaechamud, Thawatchai; Mahadlek, Jongjan

2015-10-15

Solvent-exchanged in situ forming gel is a drug delivery system which is in sol form before administration. When it contacts with the body fluid, then the water miscible organic solvent dissipates and water penetrates into the system, leading the polymer precipitation as in situ gel at the site of injection. The aim of this research was to study the parameters affecting the gel properties, drug release and antimicrobial activities of the in situ forming gels prepared from ethyl cellulose (EC) dissolved in N-methyl pyrrolidone (NMP) to deliver the antimicrobial agents (doxycycline hyclate, metronidazole and benzyl peroxide) for periodontitis treatment. The gel appearance, pH, viscosity, rheology, syringeability, gel formation, rate of water diffusion into the gels, in vitro degradation, drug release behavior and antimicrobial activities against Staphylococcus aureus, Escherichia coli, Candida albicans, Streptococcus mutans and Porphyrommonas gingivalis were determined. Increasing the amount of EC increased the viscosity of system while still exhibiting Newtonian flow and increased the work of syringeability whereas decreased the releasing of drug. The system transformed into the rigid gel formation after being injected into the simulated gingival crevicular fluid. The developed systems containing 5% w/w antimicrobial agent showed the antimicrobial activities against all test bacteria. Thus the developed solvent exchange-induced in situ forming gels comprising EC-antimicrobial drugs exhibited potential use for periodontitis treatment. Copyright © 2015 Elsevier B.V. All rights reserved.

Differential saliva-induced breakdown of starch filled protein gels in relation to sensory perception

NARCIS (Netherlands)

Janssen, A.M.; Pijpekamp, A.M. van de; Labiausse, D.

2009-01-01

In this study, the differential breakdown of protein gels containing four types of high and low cross-linked starch granules were studied. Susceptibility to saliva-induced breakdown of starch granules and the consequences of these for overall breakdown of the gel matrix were captured using a

Spontaneous and radiation induced cell death in HeLa S3 human carcinoma

International Nuclear Information System (INIS)

Zaric, B.; Milosavljevic, B.; Radojcic, M.

2001-01-01

Radiation biologists have classified radiation-induced cell death based on cell proliferative capacity to either mitotic or interphase death. Cytologists have revealed two morphologically and biochemically diverse forms of cell death, apoptosis and necrosis. While the knowledge of the former is already well exploited by radiologists, cell susceptibility to apoptosis and necrosis is still under investigation. We studied characteristics of spontaneous cell death, and dose dependence and time course of radiation-induced cell death of human uterine cervix epitheloid carcinoma HeLaS 3 in culture. Cells were irradiated with 2-40 Gy of γ-rays. The effect on growth, viability, morphology and genomic DNA structure were followed 24-72 h after irradiation. Cell viability was evaluated by trypan-blue exclusion assay and cell morphology by in situ DNA staining with propidium iodide. Cell genomic DNA fragmentation pattern was determined by electrophoresis on 2% agarose gels. At all cell densities 25-35% cells were PI positive and their DNA was fragmented to a high molecular size (≥20 kbp), but the internucleosomal ladder was not observed. A significant decrease in viability to 33% was observed 72 h post 40 Gy irradiation. It corresponded to 55% of PI positive cells. A smear of smaller DNA fragments (0.1-1 kbp), 24 h after 10-20 Gy irradiation was considered as proof that the dominant form of radiation-induced cell death was necrosis. It was concluded that the dominant form of radiation-induced cell death in HeLaS 3 population was necrosis and the radiation dose which caused 50% of cell death after 72 h (termed ND 50 ) was between 30-40 Gy. (author)

A comparative in vitro study of the digestibility of heat- and high pressure-induced gels prepared from industrial milk whey proteins

Science.gov (United States)

He, Jin-Song; Mu, Tai-Hua; Wang, Juan

2013-06-01

We undertook this study to compare the digestibility of heat- and high pressure-induced gels produced from whey protein isolate (WPI). To simulate in vivo gastrointestinal digestion of WPI gels, a pepsin-trypsin digestion system was used. The in vitro protein digestibility of WPI gels induced by high pressure (400 MPa and 30 min; P-gel) and those induced by heat (80°C and 30 min; H-gel) was compared using a protein concentration of 0.14 g mL-1. The in vitro protein digestibility of P-gels was significantly greater than that of H-gels (p<0.05). The size-exclusion chromatography profiles of the hydrolysates showed that the P-gel generated more and smaller peptides than natural WPI and H-gels. Furthermore, Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis showed some soluble disulfide-mediated aggregation in the P-gel, while there was more insoluble aggregation in the H-gel than the P-gel. The P-gel was more sensitive to proteinase than the H-gel, which was related to the content of S-S bonds, and this in turn could be attributed to the differences in the gelation mechanism between the H-gel and P-gel.

Protection of vanillin derivative VND3207 on plasmid DNA damage induced by different LET ionizing radiation

International Nuclear Information System (INIS)

Xu Huihui; Wang Li; Sui Li; Guan Hua; Wang Yu; Liu Xiaodan; Zhang Shimeng; Xu Qinzhi; Wang Xiao; Zhou Pingkun

2011-01-01

Objective: To evaluate the radioprotective effect of vanillin derivative VND3207 on DNA damage induced by different LET ionizing radiation. Methods: The plasmid DNA in liquid was irradiated by 60 Co γ-rays, proton or 7 Li heavy ion with or without VND3207. The conformation changes of plasmid DNA were assessed by agarose gel electrophoresis and the quantification was done using gel imaging system. Results: The DNA damage induced by proton and 7 Li heavy ion was much more serious as compared with that by 60 Co γ-rays, and the vanillin derivative VND3207 could efficiently decrease the DNA damage induced by all three types of irradiation sources, which was expressed as a significantly reduced ratio of open circular form (OC) of plasmid DNA. The radioprotective effect of VND3207 increased with the increasing of drug concentration. The protective efficiencies of 200 μmol/L VND3207 were 85.3% (t =3.70, P=0.033), 73.3% (t=10.58, P=0.017) and 80.4% (t=8.57, P=0.008) on DNA damage induction by 50 Gy of γ-rays, proton and 7 Li heavy ion, respectively. It seemed that the radioprotection of VND3207 was more effective on DNA damage induced by high LET heavy ion than that by proton. Conclusions: VND3207 has a protective effect against the genotoxicity of different LET ionizing radiation, especially for γ-rays and 7 Li heavy ion. (authors)

A study on apoptotic signaling pathway in HL-60 cells induced by radiation

International Nuclear Information System (INIS)

Kim, Hye Jung; Moon, Sung Keun; Lee, Jae Hoon; Moon, Sun Rock

2001-01-01

The mechanical insights of death at cancer cells by ionizing radiation are not yet clearly defined. Recent evidences have demonstrated that radiation therapy may induce cell death via activation of signaling pathway for apoptosis in target cells. This study is designed whether ionizing radiation may activate the signaling cascades of apoptosis including caspase family cysteine proteases, Bcl2/Bax, cytochrome c and Fas/Fas-L in target cells. HL-60 cells were irradiated in vitro with 6 MV X-ray at dose ranges from 2 Gy to 32 Gy. The cell viability was tested by MTT assay and the extent of apoptosis was determined using agarose gel electrophoresis. The activities of caspase proteases were measured by proteolytic cleavages of substrates. Western blot analysis was used to monitor PARP, caspase-3, Cytochrome-c, BcI-2, Bax, Fas and Fas-L. Ionizing radiation decreases the viability of HL -60 cells in a time and dose dependent manner. Ionizing radiation-induced death in HL- 60 cells is an apoptotic death which is revealed as characteristic ladder-pattern fragmentation at genomic DNA over 16 Gy at 4 hours. Ionizing radiation induces the activation of caspase-2, 3, 6, 8 and 9 of HL --60 cells in a time-dependent manner. The activation of caspase- 3 protease is also evidenced by the digestion of poly (ADP-ribose) polymerase and procaspase 3 with 16Gy ionizing irradiation. Anti-apoptotic Bcl2 expression is decreased but apoptotic Bax expression is increased with mitochondrial cytochrome c release in a time- dependent manner. In addition, expression of Fas and Fas-L is also increased in a time dependent manner. These data suggest that ionizing radiation-induced apoptosis is mediated by the activation of various signaling pathways including caspase family cysteine proteases, BcI 2 /Bax, Fas and Fas-L in a time and dose dependent manner

Post-factum detection of radiation treatment of meat and fish by means of DNA alterations identified by gas chromatography-mass spectrometry or pulsed-field gel electrophoresis

International Nuclear Information System (INIS)

Mayer, M.

1994-01-01

The doctoral thesis explains methods and experiments for post-factum detection of radiation-induced alterations of DNA. There are various manifestations of such alterations. Ionizing radiation can directly alter the bases and/or sugar component, or can indirectly induce DNA damage by way of forming water radicals. Both mechanisms result in base derivatives, released for some part from the DNA strand, or formed by alterations of the 2-deoxyribose, inducing strand breaks ( single and double strand breaks). The first part of the thesis explains the approach applying GC-MS for detection of radiation-induced base derivatives, using herring sperm DNA as a model DNA. Some typical types of base derivatives were identified (thymine glycol, 5-hydroxycytosine).Some base derivatives were also found in DNA samples derived from poultry meat. These base derivatives are known to be indicators of food processing with ionizing radiation, but surprisingly were also found in non-irradiated controls, although in minor amounts. The second part discusses the identification of strand breaks applying the pused-field gel electrophoresis. This method is capable of producing evidence that irradiation markedly enhances the short-chain DNA molecules as compared to non-irradiated controls. DNA molecules of a size of approx. 2.2 million base pairs are almost completely broken into short-chain fragments. The method reliably detects radiation treatments down to 1500 Gy, even if applied long ago. (orig./MG) [de

Depletion of the type 1 IGF receptor delays repair of radiation-induced DNA double strand breaks

International Nuclear Information System (INIS)

Turney, Benjamin W.; Kerr, Martin; Chitnis, Meenali M.; Lodhia, Kunal; Wang, Yong; Riedemann, Johann; Rochester, Mark; Protheroe, Andrew S.; Brewster, Simon F.; Macaulay, Valentine M.

2012-01-01

Background and purpose: IGF-1R depletion sensitizes prostate cancer cells to ionizing radiation and DNA-damaging cytotoxic drugs. This study investigated the hypothesis that IGF-1R regulates DNA double strand break (DSB) repair. Methods: We tested effects of IGF-1R siRNA transfection on the repair of radiation-induced DSBs by immunoblotting and immunofluorescence for γH2AX, and pulsed-field gel electrophoresis. Homologous recombination (HR) was quantified by reporter assays, and cell cycle distribution by flow cytometry. Results: We confirmed that IGF-1R depletion sensitized DU145 and PC3 prostate cancer cells to ionizing radiation. DU145 control transfectants resolved radiation-induced DSBs within 24 h, while IGF-1R depleted cells contained 30–40% unrepaired breaks at 24 h. IGF-1R depletion induced significant reduction in DSB repair by HR, although the magnitude of the repair defect suggests additional contributory factors. Radiation-induced G2-M arrest was attenuated by IGF-1R depletion, potentially suppressing cell cycle-dependent processes required for HR. In contrast, IGF-1R depletion induced only minor radiosensitization in LNCaP cells, and did not influence repair. Cell cycle profiles were similar to DU145, so were unlikely to account for differences in repair responses. Conclusions: These data indicate a role for IGF-1R in DSB repair, at least in part via HR, and support use of IGF-1R inhibitors with DNA damaging cancer treatments.

Depletion of the type 1 IGF receptor delays repair of radiation-induced DNA double strand breaks.

Science.gov (United States)

Turney, Benjamin W; Kerr, Martin; Chitnis, Meenali M; Lodhia, Kunal; Wang, Yong; Riedemann, Johann; Rochester, Mark; Protheroe, Andrew S; Brewster, Simon F; Macaulay, Valentine M

2012-06-01

IGF-1R depletion sensitizes prostate cancer cells to ionizing radiation and DNA-damaging cytotoxic drugs. This study investigated the hypothesis that IGF-1R regulates DNA double strand break (DSB) repair. We tested effects of IGF-1R siRNA transfection on the repair of radiation-induced DSBs by immunoblotting and immunofluorescence for γH2AX, and pulsed-field gel electrophoresis. Homologous recombination (HR) was quantified by reporter assays, and cell cycle distribution by flow cytometry. We confirmed that IGF-1R depletion sensitized DU145 and PC3 prostate cancer cells to ionizing radiation. DU145 control transfectants resolved radiation-induced DSBs within 24 h, while IGF-1R depleted cells contained 30-40% unrepaired breaks at 24 h. IGF-1R depletion induced significant reduction in DSB repair by HR, although the magnitude of the repair defect suggests additional contributory factors. Radiation-induced G2-M arrest was attenuated by IGF-1R depletion, potentially suppressing cell cycle-dependent processes required for HR. In contrast, IGF-1R depletion induced only minor radiosensitization in LNCaP cells, and did not influence repair. Cell cycle profiles were similar to DU145, so were unlikely to account for differences in repair responses. These data indicate a role for IGF-1R in DSB repair, at least in part via HR, and support use of IGF-1R inhibitors with DNA damaging cancer treatments. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Conducting polymer electrodes for gel electrophoresis.

Directory of Open Access Journals (Sweden)

Katarina Bengtsson

Full Text Available In nearly all cases, electrophoresis in gels is driven via the electrolysis of water at the electrodes, where the process consumes water and produces electrochemical by-products. We have previously demonstrated that π-conjugated polymers such as poly(3,4-ethylenedioxythiophene (PEDOT can be placed between traditional metal electrodes and an electrolyte to mitigate electrolysis in liquid (capillary electroosmosis/electrophoresis systems. In this report, we extend our previous result to gel electrophoresis, and show that electrodes containing PEDOT can be used with a commercial polyacrylamide gel electrophoresis system with minimal impact to the resulting gel image or the ionic transport measured during a separation.

Conducting polymer electrodes for gel electrophoresis.

Science.gov (United States)

Bengtsson, Katarina; Nilsson, Sara; Robinson, Nathaniel D

2014-01-01

In nearly all cases, electrophoresis in gels is driven via the electrolysis of water at the electrodes, where the process consumes water and produces electrochemical by-products. We have previously demonstrated that π-conjugated polymers such as poly(3,4-ethylenedioxythiophene) (PEDOT) can be placed between traditional metal electrodes and an electrolyte to mitigate electrolysis in liquid (capillary electroosmosis/electrophoresis) systems. In this report, we extend our previous result to gel electrophoresis, and show that electrodes containing PEDOT can be used with a commercial polyacrylamide gel electrophoresis system with minimal impact to the resulting gel image or the ionic transport measured during a separation.

Genomic rearrangement in radiation-induced murine myeloid leukemia

International Nuclear Information System (INIS)

Ishihara, Hiroshi

1994-01-01

After whole body irradiation of 3Gy X ray to C3H/He male mice, acute myeloid leukemia is induced at an incidence of 20 to 30% within 2 years. We have studied the mechanism of occurrence of this radiation-induced murine myeloid leukemia. Detection and isolation of genomic structural aberration which may be accumulated accompanied with leukemogenesis are helpful in analyzing the complicated molecular process from radiation damage to leukemogenesis. So, our research work was done in three phases. First, structures of previously characterized oncogenes and cytokine-related genes were analyzed, and abnormal structures of fms(protooncogene encoding M-CSF receptor gene)-related and myc-related genes were found in several leukemia cells. Additionally, genomic structural aberration of IL-3 gene was observed in some leukemia cells, so that construction of genomic libraries and cloning of the abnormal IL-3 genomic DNAs were performed to characterize the structure. Secondly, because the breakage of chromosome 2 that is frequently observed in myeloid leukemia locates in proximal position of IL-1 gene cluster in some cases, the copy number of IL-1 gene was determined and the gene was cloned. Lastly, the abnormal genome of leukemia cell was cloned by in-gel competence reassociation method. We discussed these findings and evaluated the analysis of the molecular process of leukemogenesis using these cloned genomic fragments. (author)

Radiation-induced thermoacoustic imaging

International Nuclear Information System (INIS)

Bowen, T.

1984-01-01

This invention provides a new technique for obtaining information non-invasively on the composition and structures of a material or body by detecting radiation-induced thermoacoustic image features. This is accomplished by utilizing the acoustic wave generated by sudden thermal stress. The sudden thermal stress is induced by a pulse of radiation which deposits energy causing a rapid, but very small, rise of temperature (typically, ΔT approximately 10sup(-6) - 10sup(-5) deg C). The radiation may be ionizing radiation, such as high energy electrons, photons (x-rays), neutrons, or other charged particles or it may be non-ionizing radiation, such as R.F. and microwave electromagnetic radiation and ultrasonic radiation. The choice of radiation depends on the nature of the body to be imaged and the type of information desired

The effect of vitamin D prophylaxis on radiation induced pulmonary damage

International Nuclear Information System (INIS)

Yazici, G.; Yildiz, F.; Iskit, A.; Surucu, S.; Firat, P.; Hayran, M.; Ozyigit, G.; Cengiz, M.; Erdemli, E.

2011-01-01

Vitamin D has a selective radio and chemosensitizing effect on tumor cells. In vitro and in vivo studies have shown that vitamin D inhibits collagen gel construction, induces type II pneumocyte proliferation and surfactant synthesis in the lungs, and decreases vascular permeability caused by radiation. The aim of this experimental study was to determine if vitamin D has a protective effect against radiation-induced pulmonary damage. Adult Wistar rats were divided into 4 groups. Group 1 was comprised of control animals. Group 2, which was administered 0.25 μg/kg/day of vitamin D3 for 8 weeks, was the vitamin D control group. Rats in groups 3 and 4 were given 20 Gy right hemithorax radiotherapy, and in addition group 4 was given vitamin D3 treatment, which began the day before the radiotherapy and continued for 8 weeks. At the 8 th and the 12 th weeks of the study 4 rats from each group were sacrificed. Right lungs were dissected for light and electron microscopic study. The electron microscopy examinations revealed statistically significant differences between group 3 and 4, and in group 4 there was less interstitial inflammation and collagen deposition, and the alveolar structure and the cells lining the alveolar walls were protected. These results confirm that vitamin D has a protective effect against radiation-induced pulmonary toxicity. These findings should be evaluated with further clinical studies. (author)

Physical changes on the radiation and heat induced poly(Vinyl alcohol) fibers

Energy Technology Data Exchange (ETDEWEB)

Nho, Young Chang; Park, Kyung Ran; Park, Jong Seok; Lim, Youn Mook; Kang, Phil Hyun [Research Division for Industry and Environment, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2016-11-15

Poly(vinyl alcohol) (PVA) has high tensile strength and flexibility as well as oxygen barrier properties. The water, which acts as a plasticizer, reduces the tensile strength of PVA and swells PVA as well. It needs to have high water-resistant depending on its applications, especially for the use as tire cords. The aim of this work was to investigate the effect of the annealing temperature and radiation on the Gel content and tensile strength of PVA fbers. For this purpose, gel fraction and tensile strength were determined and analyzed. Annealing was performed in the temperature range of 120-180℃ for 10 min. PVA fbers were irradiated by using a conventional electron beam irradiation at a radiation dose of 50⁓200 kGy, at a dose of 10 kGy/pass at room temperature (acceleration voltage of 1 MeV). Annealing markedly increased the Gel content and the tensile strength of PVA fbers. However irradiation lowered the Gel content and the tensile strength of PVA fbers because they were degraded easily by radiation.

Synthesis and Characterization of PVP-Grafted-Starch Hydrogels Using Gamma Radiation

International Nuclear Information System (INIS)

Suwanmala, Phiriyatorn; Hemvichian, Kasinee; Sonsuk, Manit

2004-10-01

A Series of hydrogels were prepared from gelatinized cassava starch and vinylpyrrolidone by radiation-induced graft copolymerization. Gel fraction, swelling ratio and gel strength of the obtained hydrogels were characterized. The experimental results show that the swelling ratio is inversely dependent on the radiation dose. The results from PVP-grafted-starch were subsequently compared with those of PVP hydrogels and PVP-blended-starch hydrogels. It was found that the PVP-grafted-starch hydrogels, with gel fraction higher than 80% can be prepared at the dose of 10 kGy, while PVP and PVP-blended-starch hydrogels require at least 30 kGy to obtain gels with more than 80% gel fraction

Two strategies for the development of mitochondrion-targeted small molecule radiation damage mitigators

NARCIS (Netherlands)

Rwigema, Jean-Claude M.; Beck, Barbara; Wang, Wei; Doemling, Alexander; Epperly, Michael W.; Shields, Donna; Goff, Julie P.; Franicola, Darcy; Dixon, Tracy; Frantz, Marie-Céline; Wipf, Peter; Tyurina, Yulia; Kagan, Valerian E.; Wang, Hong; Greenberger, Joel S.

2011-01-01

Purpose: To evaluate the effectiveness of mitigation of acute ionizing radiation damage by mitochondrion-targeted small molecules. Methods and Materials: We evaluated the ability of nitroxide-linked alkene peptide isostere JP4-039, the nitric oxide synthase inhibitor-linked alkene peptide esostere

Verification of motion induced thread effect during tomotherapy using gel dosimetry

International Nuclear Information System (INIS)

Edvardsson, Anneli; Ljusberg, Anna; Ceberg, Crister; Medin, Joakim; Ambolt, Lee; Nordström, Fredrik; Ceberg, Sofie

2015-01-01

The purpose of the study was to evaluate how breathing motion during tomotherapy (Accuray, CA, USA) treatment affects the absorbed dose distribution. The experiments were carried out using gel dosimetry and a motion device simulating respiratory-like motion (HexaMotion, ScandiDos, Uppsala, Sweden). Normoxic polyacrylamide gels (nPAG) were irradiated, both during respiratory-like motion and in a static mode. To be able to investigate interplay effects the static absorbed dose distribution was convolved with the motion function and differences between the dynamic and convolved static absorbed dose distributions were interpreted as interplay effects. The expected dose blurring was present and the interplay effects formed a spiral pattern in the lower dose volume. This was expected since the motion induced affects the preset pitch and the theoretically predicted thread effect may emerge. In this study, the motion induced thread effect was experimentally verified for the first time

Review of Fricke gel dosimeters

International Nuclear Information System (INIS)

Schreiner, L J

2004-01-01

The innovation of adding a gel matrix to the traditional Fricke dosimeter to stabilize geometric information established the field of gel dosimetry for radiation therapy. A discussion of Fricke gels provides an overview of the issues that determine the dose response of all gel dosimeters in general. In this paper we review some of the features of Fricke systems to illustrate these issues and, in addition, to motivate renewed clinical interest in Fricke gels

Conducting Polymer Electrodes for Gel Electrophoresis

OpenAIRE

Bengtsson, Katarina; Nilsson, Sara; Robinson, Nathaniel D

2014-01-01

In nearly all cases, electrophoresis in gels is driven via the electrolysis of water at the electrodes, where the process consumes water and produces electrochemical by-products. We have previously demonstrated that p-conjugated polymers such as poly(3,4-ethylenedioxythiophene) (PEDOT) can be placed between traditional metal electrodes and an electrolyte to mitigate electrolysis in liquid (capillary electroosmosis/electrophoresis) systems. In this report, we extend our previous result to gel ...

Kinetics of electrically and chemically induced swelling in polyelectrolyte gels

Science.gov (United States)

Grimshaw, P. E.; Nussbaum, J. H.; Grodzinsky, A. J.; Yarmush, M. L.

1990-09-01

Controlled swelling and shrinking of polyelectrolyte gels is useful for regulating the transport of solutes into, out of, and through these materials. A macroscopic continuum model is presented to predict the kinetics of swelling in polyelectrolyte gel membranes induced by augmentation of electrostatic swelling forces arising from membrane fixed charge groups. The model accounts for ionic transport within the membrane, electrodiffusion phenomena, dissociation of membrane charge groups, intramembrane fluid flow, and mechanical deformation of the membrane matrix. Model predictions are compared with measurements of chemically and electrically induced swelling and shrinking in crosslinked polymethacrylic acid (PMAA) membranes. Large, reversible changes in PMAA membrane hydration were observed after changing the bath pH or by applying an electric field to modify the intramembrane ionic environment and fixed charge density. A relatively slow swelling process and more rapid shrinking for both chemical and electrical modulation of the intramembrane pH are observed. The model indicates that retardation of membrane swelling is dominated by diffusion-limited reaction of H+ ions with membrane charge groups, and that the more rapid shrinking is limited primarily by mechanical processes.

Protective effect of zingerone, a dietary compound against radiation induced damage

International Nuclear Information System (INIS)

Satish Rao, B.S.; Rao, Nageshwar

2012-01-01

The radioprotective potential of phenolic alkanone, Zingerone (ZO) was investigated using human peripheral blood lymphocytes as well as Chinese hamster fibroblast (V79) cells growing in vitro and in vivo by using Swiss albino mice exposed to gamma radiation. In the in vivo studies, mice were administered with ZO (10-100 mg/kg b.wt), once daily for five consecutive days. One hour after the last administration of ZO on the fifth day, animals were whole body exposed to 10 Gy gamma radiations. The radioprotective potential was assessed using animal survival, haemopoietic stem cell survival (CFU) assay, mouse bone marrow micronucleus test, histological observations of intestinal and bone marrow damage. Effect of ZO pretreatment on radiation-induced changes in glutathione (GSH), glutathione-S-transferase (GST), superoxide dismutase (SOD), catalase (CAT) and lipid peroxidation (LPx) levels was also analyzed. ZO treatment resulted increase in the LD50/30 by 1.8 Gy (dose reduction factor = 1.2). The number of spleen colonies after whole body irradiation of mice (4.5 or 7.5 Gy) was increased when ZO was administered 1 h prior to irradiation. The histological observations indicated a decline in the villus height and crypt number with an increase in goblet and dead cell population in the irradiated group, which was normalized by pretreatment with ZO. A significant (p < 0.001) reduction in micronucleated polychromatic, normochromatic erythrocytes, increased PCE/NCE ratio, increase in the GSH, GST, SOD, CAT and decreased LPx levels were observed in ZO by pretreated group when compared to the irradiated animals. Our in vitro and in vivo studies demonstrate the potential of ZO in mitigating radiation-induced cytotoxic, genotoxicity, apoptosis in cell culture and animal mortality, cytogenetic damage, intestinal and bone marrow protection in vivo. Radioprotective potential of ZO may be attributed to the inhibition radiation-induced decline in the endogenous antioxidant levels

Radiation-induced centers in inorganic glasses

International Nuclear Information System (INIS)

Brekhovskikh, S.M.; Tyul'nin, V.A.

1988-01-01

The nature, structure and formation mechanisms of radiation-induced colour centers, EPR, luminescence, generated ionizing radiation in nonorganic oxide glasses are considered. Experimental material covering both fundamental aspects of radiation physics and glass chemistry, and aspects intimately connected with the creation of new materials with the given radiation-spectral characteristics, with possibilities to prepare radiation-stable and radiation-sensitive glasses is systematized and generalized. Considerable attention is paid to the detection of radiation-induced center binding with composition, glass structures redox conditions for their synthesis. Some new possibilities of practical application of glasses with radiation-induced centers, in particular, to record optical information are reflected in the paper

Cavitation bubble nucleation induced by shock-bubble interaction in a gelatin gel

Science.gov (United States)

Oguri, Ryota; Ando, Keita

2018-05-01

An optical visualization technique is developed to study cavitation bubble nucleation that results from interaction between a laser-induced shock and a preexisting gas bubble in a 10 wt. % gelatin gel; images of the nucleated cavitation bubbles are captured and the cavitation inception pressure is determined based on Euler flow simulation. A spherical gas cavity is generated by focusing an infrared laser pulse into a gas-supersaturated gel and the size of the laser-generated bubble in mechanical equilibrium is tuned via mass transfer of the dissolved gas into the bubble. A spherical shock is then generated, through rapid expansion of plasma induced by the laser focusing, in the vicinity of the gas bubble. The shock-bubble interaction is recorded by a CCD camera with flash illumination of a nanosecond green laser pulse. The observation captures cavitation inception in the gel under tension that results from acoustic impedance mismatching at the bubble interface interacting with the shock. We measure the probability of cavitation inception from a series of the repeated experiments, by varying the bubble radius and the standoff distance. The threshold pressure is defined at the cavitation inception probability equal to one half and is calculated, through comparisons to Euler flow simulation, at -24.4 MPa. This threshold value is similar to that from shock-bubble interaction experiments using water, meaning that viscoelasticity of the 10 wt. % gelatin gel has a limited impact on bubble nucleation dynamics.

Implication of microRNAs in the development and potential treatment of radiation-induced heart disease.

Science.gov (United States)

Kura, Branislav; Babal, Pavel; Slezak, Jan

2017-10-01

Radiotherapy is the most commonly used methodology to treat oncological disease, one of the most widespread causes of death worldwide. Oncological patients cured by radiotherapy applied to the mediastinal area have been shown to suffer from cardiovascular disease. The increase in the prevalence of radiation-induced heart disease has emphasized the need to seek new therapeutic targets to mitigate the negative impact of radiation on the heart. In this regard, microRNAs (miRNAs) have received considerable interest. miRNAs regulate post-transcriptional gene expression by their ability to target various mRNA sequences because of their imperfect pairing with mRNAs. It has been recognized that miRNAs modulate a diverse spectrum of cardiac functions with developmental, pathophysiological, and clinical implications. This makes them promising potential targets for diagnosis and treatment. This review summarizes the recent findings about the possible involvement of miRNAs in radiation-induced heart disease and their potential use as diagnostic or treatment targets in this respect.

DNA damage induced by radiation plasmodial mixed + gamma thermal neutrons in the presence and absence of free radical scavenger

International Nuclear Information System (INIS)

Rodriguez Gual, Maritza; Mas Milian, Felix; Gouveia, Andreia; Deppman, Airton

2010-01-01

In this work is quantified the damage in DNA plasmid induced by mixed radiation (thermal neutron and gamma rays) for first time. For the study was used the pBs KS+ plasmid of 2961 bp in aqueous solution of the 88 ng/μL with 0, 2 and 20 mmol/L of glycerol which acts as a free radicals scavenger. This plasmid changes its form of supercoiled to circular when a simple strand break is produced, and passes to a linear form when a double strand break is produced in the chain. Quantifying the fractions that exist in each of these forms is possible to estimate the effect of radiation on DNA. The irradiations were carried out in the radial channel 3 at IEA-R1 research reactor of the Instituto de Pesquisas Energeticas y Nucleares in Sao Paulo, Brazil. DNA forms were separated by agarose gel electrophoresis. For quantification the program GelAnalis was used. The values of the fractions of DNA in various forms were plotted as a function of dose and fitted to exponential and linear functions to obtaining the probabilities of simple and double strand breaks normalized by dose and molecular mass. The results showed the protective action of free radical scavenger against damage induced for radiation which corroborates the previous results found with other ionizing radiations. Yields of SSB and DSB will be of interest for the validation of the different models that attempt to reproduce the experimental results

Induced seismicity and carbon storage: Risk assessment and mitigation strategies

Energy Technology Data Exchange (ETDEWEB)

White, Joshua A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Foxall, William [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Bachmann, Corinne [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Chiaramonte, Laura [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Daley, Thomas M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2016-01-28

Geologic carbon storage (GCS) is widely recognized as an important strategy to reduce atmospheric carbon dioxide (CO₂) emissions. Like all technologies, however, sequestration projects create a number of potential environmental and safety hazards that must be addressed. These include earthquakes—from microseismicity to large, damaging events—that can be triggered by altering pore-pressure conditions in the subsurface. To date, measured seismicity due to CO₂ injection has been limited to a few modest events, but the hazard exists and must be considered. There are important similarities between CO₂ injection and fluid injection from other applications that have induced significant events—e.g. geothermal systems, waste-fluid injection, hydrocarbon extraction, and others. There are also important distinctions among these technologies that should be considered in a discussion of seismic hazard. This report focuses on strategies for assessing and mitigating risk during each phase of a CO₂ storage project. Four key risks related to fault reactivation and induced seismicity were considered. Induced slip on faults could potentially lead to: (1) infrastructure damage, (2) a public nuisance, (3) brine-contaminated drinking water, and (4) CO₂-contaminated drinking water. These scenarios lead to different types of damage—to property, to drinking water quality, or to the public welfare. Given these four risks, this report focuses on strategies for assessing (and altering) their likelihoods of occurrence and the damage that may result. This report begins with an overview of the basic physical mechanisms behind induced seismicity. This science basis—and its gaps—is crucial because it forms the foundation for risk assessment and mitigation. Available techniques for characterizing and monitoring seismic behavior are also described. Again, this technical basis—and its limitations—must be factored into the risk

Is radiation-induced cell death in mouse testis apoptosis?

International Nuclear Information System (INIS)

Hasegawa, Masatoshi; Wilson, Gene; Yun Zhang; Russell, Lonnie D.; Meistrich, Marvin L.

1996-01-01

Purpose: Radiation-induced death of spermatogonia and other germ cells in the testis has been claimed to be by an apoptotic mechanism, but these processes have been incompletely characterized. We investigated irradiated mouse testis by multiple techniques to determine whether the mode of cell death of spermatogonia can be classified as apoptosis. Materials and Methods: Adult male C57BL/6 and p53 knockout mice were irradiated with single doses of 0.5, 2.5 or 5.0 Gy. Four, 6, 8, 12, 18 or 24 hours after irradiation, testes were fixed in Bouin's solution or in 10% formalin. Slides were stained with hematoxylin and eosin or TdT-mediated dUTP-biotin nick end labeling (TUNEL). Some testes were perfusion-fixed with 5% glutaraldehyde for electron microscopy. Gel electrophoresis of DNA was also performed to identify DNA fragmentation. The number of sperm heads was counted 29 days after irradiation to evaluate the effect of radiation on the eventual survival of the differentiated spermatogonia. Results: The earliest sign of histological damage was an increase in the numbers of abnormal spermatogonia in the seminiferous tubules, particularly in stage I-VI of the seminiferous epithelial cycle. The numbers of abnormal spermatogonia began to increase at 6 hours, reached a peak 12 hours after irradiation, and then declined. The total number of spermatogonia began to decrease at 12 hours after irradiation, resulting in a 60% decline in sperm produced 29 days after 0.5 Gy. Although changes were greatest following 5.0 Gy irradiation, even 0.5 Gy induced marked changes. However, these changes were not induced in p53 knockout mice. By both light and electron microscopy, spermatogonia showed some condensation of nuclear chromatin, but margination of chromatin with clear delineation and nuclear fragmentation was rare. Many of the abnormal spermatogonia showed a positive TUNEL reaction, which was also at a maximum at 12 hours after irradiation. In addition, some TUNEL-positive and

Radiation-induced camptocormia and dropped head syndrome. Review and case report of radiation-induced movement disorders

International Nuclear Information System (INIS)

Seidel, Clemens; Kuhnt, Thomas; Kortmann, Rolf-Dieter; Hering, Kathrin

2015-01-01

In recent years, camptocormia and dropped head syndrome (DHS) have gained attention as particular forms of movement disorders. Camptocormia presents with involuntary forward flexion of the thoracolumbar spine that typically increases during walking or standing and may severely impede walking ability. DHS is characterized by weakness of the neck extensors and a consecutive inability to extend the neck; in severe cases the head is fixed in a ''chin to chest position.'' Many diseases may underlie these conditions, and there have been some reports about radiation-induced camptocormia and DHS. A PubMed search with the keywords ''camptocormia,'' ''dropped head syndrome,'' ''radiation-induced myopathy,'' ''radiation-induced neuropathy,'' and ''radiation-induced movement disorder'' was carried out to better characterize radiation-induced movement disorders and the radiation techniques involved. In addition, the case of a patient developing camptocormia 23 years after radiation therapy of a non-Hodgkin's lymphoma of the abdomen is described. In total, nine case series of radiation-induced DHS (n = 45 patients) and - including our case - three case reports (n = 3 patients) about radiogenic camptocormia were retrieved. Most cases (40/45 patients) occurred less than 15 years after radiotherapy involving extended fields for Hodgkin's disease. The use of wide radiation fields including many spinal segments with paraspinal muscles may lead to radiation-induced movement disorders. If paraspinal muscles and the thoracolumbar spine are involved, the clinical presentation can be that of camptocormia. DHS may result if there is involvement of the cervical spine. To prevent these disorders, sparing of the spine and paraspinal muscles is desirable. (orig.) [de

Processed Aloe vera Gel Ameliorates Cyclophosphamide-Induced Immunotoxicity

Directory of Open Access Journals (Sweden)

Sun-A Im

2014-10-01

Full Text Available The effects of processed Aloe vera gel (PAG on cyclophosphamide (CP-induced immunotoxicity were examined in mice. Intraperitoneal injection of CP significantly reduced the total number of lymphocytes and erythrocytes in the blood. Oral administration of PAG quickly restored CP-induced lymphopenia and erythropenia in a dose-dependent manner. The reversal of CP-induced hematotoxicity by PAG was mediated by the functional preservation of Peyer’s patch cells. Peyer’s patch cells isolated from CP-treated mice, which were administered PAG, produced higher levels of T helper 1 cytokines and colony-stimulating factors (CSF in response to concanavalin A stimulation as compared with those isolated from CP-treated control mice. PAG-derived polysaccharides directly activated Peyer’s patch cells isolated from normal mice to produce cytokines including interleukin (IL-6, IL-12, interferon-γ, granulocyte-CSF, and granulocyte-macrophage-CSF. The cytokines produced by polysaccharide-stimulated Peyer’s patch cells had potent proliferation-inducing activity on mouse bone marrow cells. In addition, oral administration of PAG restored IgA secretion in the intestine after CP treatment. These results indicated that PAG could be an effective immunomodulator and that it could prevent CP-induced immunotoxic side effects.

Sodium Dodecyl Sulfate- Polyacrylamide Gel Electrophoresis (SDS- PAGE) of Irradiated Wheat Flour Proteins

International Nuclear Information System (INIS)

Souzan, R.M.

1999-01-01

Sodium dodecyl sulfate - polyacrylamide gel electrophoresis (SDS-PAGE) of wheat (Triticum aestivum L) flour have revealed 23 polypeptides of molecular weights between 170 and 11.57 KDa, High molecular weight glutenin subunits (LMW-GS) were distinguished. Densitometric analysis of the gel showed the effect of radiation on polypeptide constitution at radiation energy up to 7.5 kGy. Irradiation of wheat flour with 2.5 kGy have resulted in a slight increase in the molecular weight of wheat flour protein subunits. The increase of irradiation dose to 5.0 kGy has also induced an additional increase of molecular weight of protein subunits. The continuity in application of more radiation energy to a level of 7.5 kGy have resulted in the prevalence of degradation processes of all protein subunits more than the aggregation

Contribution of radiation-induced, nitric oxide-mediated bystander effect to radiation-induced adaptive response.

Science.gov (United States)

Matsumoto, H.; Ohnishi, T.

There has been a recent upsurge of interest in radiation-induced adaptive response and bystander effect which are specific modes in stress response to low-dose low-dose rate radiation Recently we found that the accumulation of inducible nitric oxide NO synthase iNOS in wt p53 cells was induced by chronic irradiation with gamma rays followed by acute irradiation with X-rays but not by each one resulting in an increase in nitrite concentrations of medium It is suggested that the accumulation of iNOS may be due to the depression of acute irradiation-induced p53 functions by pre-chronic irradiation In addition we found that the radiosensitivity of wt p53 cells against acute irradiation with X-rays was reduced after chronic irradiation with gamma rays This reduction of radiosensitivity of wt p53 cells was nearly completely suppressed by the addition of NO scavenger carboxy-PTIO to the medium This reduction of radiosensitivity of wt p53 cells is just radiation-induced adaptive response suggesting that NO-mediated bystander effect may considerably contribute to adaptive response induced by radiation

“Beating speckles” via electrically-induced vibrations of Au nanorods embedded in sol-gel

Science.gov (United States)

Ritenberg, Margarita; Beilis, Edith; Ilovitsh, Asaf; Barkai, Zehava; Shahmoon, Asaf; Richter, Shachar; Zalevsky, Zeev; Jelinek, Raz

2014-01-01

Generation of macroscopic phenomena through manipulating nano-scale properties of materials is among the most fundamental goals of nanotechnology research. We demonstrate cooperative “speckle beats” induced through electric-field modulation of gold (Au) nanorods embedded in a transparent sol-gel host. Specifically, we show that placing the Au nanorod/sol-gel matrix in an alternating current (AC) field gives rise to dramatic modulation of incident light scattered from the material. The speckle light patterns take form of “beats”, for which the amplitude and frequency are directly correlated with the voltage and frequency, respectively, of the applied AC field. The data indicate that the speckle beats arise from localized vibrations of the gel-embedded Au nanorods, induced through the interactions between the AC field and the electrostatically-charged nanorods. This phenomenon opens the way for new means of investigating nanoparticles in constrained environments. Applications in electro-optical devices, such as optical modulators, movable lenses, and others are also envisaged. PMID:24413086

Synthesis of EVA/MWNT nanocomposites by radiation induced crosslinking

International Nuclear Information System (INIS)

Dubey, K.A.; Bhardwaj, Y.K.; Chaudhari, C.V.; Sabharwal, S.

2008-01-01

Full text: EVA is widely used as an insulating material for high voltage cables and in the footwear and toy industries due to its high flexibility and chemical inertness. The nano-composites of EVA with MWNT are of the special interest because incorporation of suitable amount of MWNT in EVA matrix is expected to significantly enhance EVA's thermal and mechanical properties, and open a new domain of applications. The modification of EVA by using high-energy radiation and with particulate filler has been widely practiced; however, there is not much information available on the radiation processing of EVA nanocomposites. To understand the effect of radiation and of MWNT addition on the physico-mechanical characteristics of EVA, different compositions of ethylene vinyl acetate (EVA)/multiple walled carbon nanotube (MWNT) nanocomposites were prepared by mixing in Brabender and subjected to different doses of gamma radiation. The efficiency of radiation vulcanization was analyzed by gel-content, Charlesby-Pinner parameter and crosslinking density measurements. Gamma radiation induced crosslinking was found to increase with MWNT fraction in EVA/MWNT nanocomposites (P o /q o range: 1.15-0.98). These results ruled out the possibility of a significant neutralization of single ionization spurs by MWNT addition. The polymer-filler interaction parameter determined from Kraus plot indicated good interaction between EVA and MWNTs. Storage modulus changed from 7 x 10 7 Pa to 1.8 x 10 8 Pa with incorporation of 5% (wt/wt) MWNT while density increased from 0.78 g/cc to 0.80 g/cc

Common genomic signaling among initial DNA damage and radiation-induced apoptosis in peripheral blood lymphocytes from locally advanced breast cancer patients

DEFF Research Database (Denmark)

Henríquez-Hernández, Luis Alberto; Pinar, Beatriz; Carmona-Vigo, Ruth

2013-01-01

PURPOSE: To investigate the genomic signaling that defines sensitive lymphocytes to radiation and if such molecular profiles are consistent with clinical toxicity; trying to disclose the radiobiology mechanisms behind these cellular processes. PATIENTS AND METHODS: Twelve consecutive patients...... suffering from locally advanced breast cancer and treated with high-dose hyperfractionated radiotherapy were recruited. Initial DNA damage was measured by pulsed-field gel electrophoresis and radiation-induced apoptosis was measured by flow cytometry. Gene expression was assessed by DNA microarray. RESULTS...

Influence of the gel thickness on in vivo hyaline cartilage regeneration induced by double-network gel implanted at the bottom of a large osteochondral defect: Short-term results

Directory of Open Access Journals (Sweden)

Matsuda Hidetoshi

2013-01-01

Full Text Available Abstract Background A double-network (DN gel, which is composed of poly(2-acrylamido-2-methylpropanesulfonic acid and poly(N,N’-dimethyl acrylamide, can induce hyaline cartilage regeneration in vivo in a large osteochondral defect. The purpose of this study was to clarify the influence of the thickness of the implanted DN gel on the induction ability of hyaline cartilage regeneration. Methods Thirty-eight mature rabbits were used in this study. We created an osteochondral defect having a diameter of 4.3-mm in the patellofemoral joint. The knees were randomly divided into 4 groups (Group I: 0.5-mm thick gel, Group II: 1.0-mm thick gel, Group III: 5.0-mm thick gel, and Group IV: untreated control. Animals in each group were further divided into 3 sub-groups depending on the gel implant position (2.0-, 3.0-, or 4.0-mm depth from the articular surface in the defect. The regenerated tissues were evaluated with the Wayne’s gross and histological grading scales and real time PCR analysis of the cartilage marker genes at 4 weeks. Results According to the total Wayne’s score, when the depth of the final vacant space was set at 2.0 mm, the scores in Groups I, II, and III were significantly greater than that Group IV (p  Conclusions The 1.0-mm thick DN gel sheet had the same ability to induce hyaline cartilage regeneration as the 5.0-mm thick DN gel plug. However, the induction ability of the 0.5-mm thick sheet was significantly lower when compared with the 1.0-mm thick gel sheet. The 1.0-mm DN gel sheet is a promising device to establish a cell-free cartilage regeneration strategy that minimizes bone loss from the gel implantation.

Selenoprotein P Inhibits Radiation-Induced Late Reactive Oxygen Species Accumulation and Normal Cell Injury

Energy Technology Data Exchange (ETDEWEB)

Eckers, Jaimee C.; Kalen, Amanda L.; Xiao, Wusheng; Sarsour, Ehab H.; Goswami, Prabhat C., E-mail: prabhat-goswami@uiowa.edu

2013-11-01

Purpose: Radiation is a common mode of cancer therapy whose outcome is often limited because of normal tissue toxicity. We have shown previously that the accumulation of radiation-induced late reactive oxygen species (ROS) precedes cell death, suggesting that metabolic oxidative stress could regulate cellular radiation response. The purpose of this study was to investigate whether selenoprotein P (SEPP1), a major supplier of selenium to tissues and an antioxidant, regulates late ROS accumulation and toxicity in irradiated normal human fibroblasts (NHFs). Methods and Materials: Flow cytometry analysis of cell viability, cell cycle phase distribution, and dihydroethidium oxidation, along with clonogenic assays, were used to measure oxidative stress and toxicity. Human antioxidant mechanisms array and quantitative real-time polymerase chain reaction assays were used to measure gene expression during late ROS accumulation in irradiated NHFs. Sodium selenite addition and SEPP1 overexpression were used to determine the causality of SEPP1 regulating late ROS accumulation and toxicity in irradiated NHFs. Results: Irradiated NHFs showed late ROS accumulation (4.5-fold increase from control; P<.05) that occurs after activation of the cell cycle checkpoint pathways and precedes cell death. The mRNA levels of CuZn- and Mn-superoxide dismutase, catalase, peroxiredoxin 3, and thioredoxin reductase 1 increased approximately 2- to 3-fold, whereas mRNA levels of cold shock domain containing E1 and SEPP1 increased more than 6-fold (P<.05). The addition of sodium selenite before the radiation treatment suppressed toxicity (45%; P<.05). SEPP1 overexpression suppressed radiation-induced late ROS accumulation (35%; P<.05) and protected NHFs from radiation-induced toxicity (58%; P<.05). Conclusion: SEPP1 mitigates radiation-induced late ROS accumulation and normal cell injury.

Radiation-induced instability of human genome

International Nuclear Information System (INIS)

Ryabchenko, N.N.; Demina, Eh.A.

2014-01-01

A brief review is dedicated to the phenomenon of radiation-induced genomic instability where the increased level of genomic changes in the offspring of irradiated cells is characteristic. Particular attention is paid to the problems of genomic instability induced by the low-dose radiation, role of the bystander effect in formation of radiation-induced instability, and its relationship with individual radiosensitivity. We believe that in accordance with the paradigm of modern radiobiology the increased human individual radiosensitivity can be formed due to the genome instability onset and is a significant risk factor for radiation-induced cancer

Manual of radiation processing of cassava starch hydrogel

International Nuclear Information System (INIS)

Sonsuk, Manit

2007-01-01

The radiation processing of natural cassava starch (CS) is described for the improvement of its properties. A series of hydrogels were prepared from gelatinized CS and vinylpyrrolidone by radiation-induced graft copolymerization. Hydrogels were also synthesized from radiation-induced crosslinking of carboxymethyl CS. The optimum condition for the swelling ratio and gel fraction of the obtained hydrogels is irradiation at low dose. The polymeric chelating resins containing the hydroxamic acid groups were synthesized from the polymethyl acrylate (PMA)-grafted CS via gamma radiation. (M.H.)

Infrared and laser-Raman spectroscopic studies of thermally-induced globular protein gels.

Science.gov (United States)

Clark, A H; Saunderson, D H; Suggett, A

1981-03-01

Infrared and laser-Raman spectroscopy have been used to follow secondary structure changes during the heat-set gelation of a number of aqueous (D2O) globular protein solutions. Measurements of the infrared Amide I' absorption band around 1650 cm-1, for BSA gels of varying clarity and texture, have shown that the very considerable variations in network structure underlying these materials are not reflected in obvious differences in secondary structure. In all cases aggregation is accompanied by development of beta-sheet of a kind common in fibrous protein systems, but for BSA at least this does not appear to vary significantly in amount from one gel type to another. Infrared studies of gels formed from other protein systems have confirmed this tendency for beta-sheet to develop during aggregation, and the tendency is further substantiated by laser-Raman evidence which provides the extra information that in most of the examples studied alpha-helix content simultaneously falls. From these, and other observations, some generalisations are made about the thermally-induced sol-to-gel transformations of globular proteins.

Protein structural development of threadfin bream ( Nemipterus spp.) surimi gels induced by glucose oxidase.

Science.gov (United States)

Wang, Lei; Fan, Daming; Fu, Lulu; Jiao, Xidong; Huang, Jianlian; Zhao, Jianxin; Yan, Bowen; Zhou, Wenguo; Zhang, Wenhai; Ye, Weijian; Zhang, Hao

2018-01-01

This study investigated the effect of glucose oxidase on the gel properties of threadfin bream surimi. The gel strength of surimi increased with the addition of 0.5‰ glucose oxidase after two-step heating. Based on the results of the chemical interactions, the hydrophobic interaction and disulfide bond of glucose oxidase-treated surimi samples increased compared with the control samples at the gelation temperature and gel modori temperature. The surface hydrophobicity of samples with glucose oxidase and glucose increased significantly ( p glucose oxidase induced more α-helixes to turn into a more elongated random and flocculent structure. Glucose oxidase changes the secondary structure of the surimi protein, making more proteins depolarize and stretch and causing actomyosin to accumulate to each other, resulting in the formation of surimi gel.

Categorization of rheological scaling models for particle gels applied to casein gels

NARCIS (Netherlands)

Mellema, M.; Opheusden, van J.H.J.; Vliet, van T.

2002-01-01

Rennet-induced casein gels made from skim milk were studied rheologically. A scaling model or framework for describing the rheological behavior of gels is discussed and used for classification of the structure of casein gels. There are two main parameters in the model that describe the number of

A Theoretical Evaluation of Secondary Atomization Effects on Engine Performance for Aluminum Gel Propellants

Science.gov (United States)

Mueller, D. C.; Turns, S. R.

1994-01-01

A one-dimensional model of a gel-fueled rocket combustion chamber has been developed. This model includes the processes of liquid hydrocarbon burnout, secondary atomization. aluminum ignition, and aluminum combustion. Also included is a model of radiative heat transfer from the solid combustion products to the chamber walls. Calculations indicate that only modest secondary atomization is required to significantly reduce propellant burnout distances, aluminum oxide residual size and radiation heat wall losses. Radiation losses equal to approximately 2-13 percent of the energy released during combustion were estimated. A two-dimensional, two-phase nozzle code was employed to estimate radiation and nozzle two-phase flow effects on overall engine performance. Radiation losses yielded a 1 percent decrease in engine I(sub sp). Results also indicate that secondary atomization may have less effect on two-phase losses than it does on propellant burnout distance and no effect if oxide particle coagulation and shear induced droplet breakup govern oxide particle size. Engine I(sub sp) was found to decrease from 337.4 to 293.7 seconds as gel aluminum mass loading was varied from 0-70 wt percent. Engine I(sub sp) efficiencies, accounting for radiation and two-phase flow effects, on the order of 0.946 were calculated for a 60 wt percent gel, assuming a fragmentation ratio of 5.

Obtention of gelatin biopolymers by ionizing radiation

International Nuclear Information System (INIS)

Takinami, Patricia Yoko Inamura

2014-01-01

The gelatin (Gel) is a biocompatible and biodegradable biopolymer, which naturally forms semi-solid colloids or hydrogels in aqueous solutions. As a hydrophilic polymer, the Gel has structural and physico-mechanical properties that distinguish it from synthetic hydrophilic polymers. The study of these properties led to the development of the present work. Thus, Gel-based films and hydrogels were developed using ionizing radiation technology by different techniques: irradiation with 60 Co, electron beam (EB) and/or pulsed EB. The Gel based-films enriched with different additives, such as glycerol (GLY), polyvinyl alcohol (PVA), butylated hydroxytoluene (BHT), acrylamide and/or vegetal fiber, were irradiated with doses from 10 to 60 kGy, depending on the additive; some parameters like mechanical properties, color, and water absorption were analyzed. In the radio-induced synthesis of GEL nanohydrogels, polyethylene glycol (PEG) and the mixture (MIX) of additives, PEG and GEL, the size, molar mass and surface morphology of the nanohydrogels were analyzed. There was a significant increase of gel fraction with increase of the radiation dose for the GEL/fiber samples. The GEL based-films with 10% PVA irradiated at 20 kGy showed the highest puncture strength. The addition of antioxidant BHT affected on some GEL based-films properties on applied conditions. Regarding the nanohydrogels, there was a decrease of hydrodynamic radius of MIX irradiated with 60 Co from 68 ± 25 nm (2 kGy) to 35 ± 4 nm (5 kGy). The radiation proved to be a convenient tool in the modification of polymeric materials for both, GEL films and hydrogels. (author)

Administration of dried Aloe vera gel powder reduced body fat mass in diet-induced obesity (DIO) rats.

Science.gov (United States)

Misawa, Eriko; Tanaka, Miyuki; Nabeshima, Kazumi; Nomaguchi, Kouji; Yamada, Muneo; Toida, Tomohiro; Iwatsuki, Keiji

2012-01-01

The aim of the present study was to investigate the anti-obesity effects of Aloe vera gel administration in male Sprague-Dawley (SD) rats with diet-induced obesity (DIO). SD rats at 7 wk of age were fed either a standard diet (10 kcal% fat) (StdD) or high-fat (60 kcal% fat) diet (HFD) during the experimental period. Four weeks after of HFD-feeding, DIO rats (11 wk of age) were orally administered with two doses of Aloe vera gel powder (20 and 200 mg/kg/d) for 90 d. Body weights (g) and body fat (%) of HFD fed rats were significantly higher than those of StdD-fed rats. Although a modest decrease of body weight (g) was observed with the administration of dried Aloe vera gel powder, both subcutaneous and visceral fat weight (g) and body fat (%) were reduced significantly in Aloe vera gel-treated rats. Serum lipid parameters elevated by HFD were also improved by the Aloe vera gel treatment. The oxygen consumption (VO(2)), an index of energy expenditure, was decreased in HFD-fed rats compared with that in StdD-fed rats. Administration of Aloe vera gel reversed the change in VO(2) in the HFD-fed rats. These results suggest that intake of Aloe vera gel reduced body fat accumulation, in part, by stimulation of energy expenditure. Aloe vera gel might be beneficial for the prevention and improvement of diet-induced obesity.

Radiation-induced heart injury

International Nuclear Information System (INIS)

Suzuki, Yoshihiko; Niibe, Hideo

1975-01-01

In order to identify radiation-induced heart injury and to differentiate it from heart disease, an attempt was made to clarify post-irradiation heart injury by investigating the histological changes which occur during the internal between the irradiation and the time of demonstrable histological changes. A study was made of 83 autopsies in which most of the primary neoplasms were breast cancers, lung cancers and mediastinal tumors. In 43 of these autopsies the heart had been irradiated. Sixty eight dd-strain mice were also used for microautoradiographic study. Histological changes in the heart were observed in 27 of the 43 cases receiving irradiation. The limit of the tolerance dose to the heart for indicating histological changes was 1220 ret in humans. The latent period without histological changes was 2.7 months after initiation of radiation therapy. Greater heart injury was observed after re-irradiation or after the combined therapy of radiation and chemotherapy especially mitomycin (MMC). The histological findings after treatment with MMC were similar to those of radiation-induced heart injury. Results of the study indicate that the damage is secondary to radiation-induced changes of the vascula connective tissue. (Evans, G.)

Study on the non-target effect of ionizing radiation using single cell gel electrophoresis

International Nuclear Information System (INIS)

Wang Yan; Li Deguan; Liu Jianfeng; Chu Liping; Liu Qiang

2008-01-01

Objective: To assess the non-target effect of ionizing radiation by single cell gel electrophoresis (SCGE). Methods: Cross incubated the irradiated( 137 Cs; 2Gy) or non-irradiated lymphocytes of human peripheral blood in the irradiated or non-irradiated plasma respectively, then, assess the DNA damage of lymphocytes using SCGE analysis. Results: The lymphocytes incubated in the irradiated plasma presented more obvious DNA damage than the incubated in the non-irradiated plasma dose (P<0.05). Conclusion: The non-target effect of ionizing radiation can be assessed by SCGE, and the results confirm that cytokines may play a great role in it. (authors)

Novel BCH Code Design for Mitigation of Phase Noise Induced Cycle Slips in DQPSK Systems

DEFF Research Database (Denmark)

Leong, M. Y.; Larsen, Knud J.; Jacobsen, G.

2014-01-01

We show that by proper code design, phase noise induced cycle slips causing an error floor can be mitigated for 28 Gbau d DQPSK systems. Performance of BCH codes are investigated in terms of required overhead......We show that by proper code design, phase noise induced cycle slips causing an error floor can be mitigated for 28 Gbau d DQPSK systems. Performance of BCH codes are investigated in terms of required overhead...

Impacts of aerosol pollutant mitigation on lowland rice yields in China

Science.gov (United States)

Zhang, Tianyi; Li, Tao; Yue, Xu; Yang, Xiaoguang

2017-10-01

Aerosol pollution in China is significantly altering radiative transfer processes and is thereby potentially affecting rice photosynthesis and yields. However, the response of rice photosynthesis to aerosol-induced radiative perturbations is still not well understood. Here, we employ a process-based modelling approach to simulate changes in incoming radiation (RAD) and the diffuse radiation fraction (DF) with aerosol mitigation in China and their associated impacts on rice yields. Aerosol reduction has the positive effect of increasing RAD and the negative effect of decreasing DF on rice photosynthesis and yields. In rice production areas where the average RAD during the growing season is lower than 250 W m-2, aerosol reduction is beneficial for higher rice yields, whereas in areas with RAD>250 W m-2, aerosol mitigation causes yield declines due to the associated reduction in the DF, which decreases the light use efficiency. As a net effect, rice yields were estimated to significantly increase by 0.8%-2.6% with aerosol concentrations reductions from 20 to 100%, which is lower than the estimates obtained in earlier studies that only considered the effects of RAD. This finding suggests that both RAD and DF are important processes influencing rice yields and should be incorporated into future assessments of agricultural responses to variations in aerosol-induced radiation under climate change.

Radiation-induced gene expression in human subcutaneous fibroblasts is predictive of radiation-induced fibrosis

DEFF Research Database (Denmark)

Rødningen, Olaug Kristin; Børresen-Dale, Anne-Lise; Alsner, Jan

2008-01-01

BACKGROUND AND PURPOSE: Breast cancer patients show a large variation in normal tissue reactions after ionizing radiation (IR) therapy. One of the most common long-term adverse effects of ionizing radiotherapy is radiation-induced fibrosis (RIF), and several attempts have been made over the last...... years to develop predictive assays for RIF. Our aim was to identify basal and radiation-induced transcriptional profiles in fibroblasts from breast cancer patients that might be related to the individual risk of RIF in these patients. MATERIALS AND METHODS: Fibroblast cell lines from 31 individuals......-treated fibroblasts. Transcriptional differences in basal and radiation-induced gene expression profiles were investigated using 15K cDNA microarrays, and results analyzed by both SAM and PAM. RESULTS: Sixty differentially expressed genes were identified by applying SAM on 10 patients with the highest risk of RIF...

Proteomics analysis of ram sperm by heavy ion radiation

International Nuclear Information System (INIS)

He Yuxuan; Li Hongyan; Zhang Hong

2013-01-01

The objective of this study was to investigate the proteome changes induced by heavy ion radiation using irradiated ram sperm by a two-dimensional electrophoresis (2-DE) analysis. The 2D gels were stained with Coomassie Brilliant Blue. Differentially expressed proteins were detected by PDQuest 8.0 software and subjected to ion trap mass spectrometer equipped with a surveyor HPLC system, and differential protein spots were identified. Results showed there are five differential protein spots in irradiated sperm gels, four up-regulated protein spots and one spot missed. The differentially expressed protein spots were identified to be two up-regulated proteins including enolase, and enolase 1. It was concluded there was proteome changes induced by heavy ion radiation in ram sperm, which may be useful to clarify the physiology state of ram sperm in heavy ion radiation and provide a theoretical basis for radiation ram breeding. (authors)

Occupational and environmental exposures to radon: A perspective for mitigators

International Nuclear Information System (INIS)

Sanchez, D.C.; Messing, M.; Saum, D.

1989-01-01

This paper compares normal environmental and occupational exposures to radon and radon decay products for the occupational group, including radon mitigators and diagnosticians. Occupational exposures to radon and radon decay products and the associated high incidence of radiation-induced lung cancer form the basis for current concern for limiting exposures to radon. While it is now known that radon is a ubiquitous environmental pollutant and estimates exist as to what this means in terms of cancer risk to the general population, similar estimates are not available for radon mitigators and diagnosticians

Application of radiation-induced apoptosis in radiation oncology and radiation protection

International Nuclear Information System (INIS)

Crompton, N.E.A.; Emery, G.C.; Ozsahin, M.; Menz, R.; Knesplova, L.; Larsson, B.

1997-01-01

A rapid assay of the ability of lymphocytes to respond to radiation-induced damage is presented. Age and genetic dependence of radiation response have been quantified. The assay is sensitive to low doses of radiation. Its ability to assess the cytotoxic response of blood capillaries to radiation has been evaluated. (author)

Light-induced spatial control of pH-jump reaction at smart gel interface.

Science.gov (United States)

Techawanitchai, Prapatsorn; Ebara, Mitsuhiro; Idota, Naokazu; Aoyagi, Takao

2012-11-01

We proposed here a 'smart' control of an interface movement of proton diffusion in temperature- and pH-responsive hydrogels using a light-induced spatial pH-jump reaction. A photoinitiated proton-releasing reaction of o-nitrobenzaldehyde (NBA) was integrated into poly(N-isopropylacrylamide-o-2-carboxyisopropylacrylamide) (P(NIPAAm-co-CIPAAm)) hydrogels. NBA-integrated hydrogels demonstrated quick release of proton upon UV irradiation, allowing the pH inside the gel to decrease below the pK(a) of P(NIPAAm-co-CIPAAm) within a minute. The NBA-integrated gel was shown to shrink rapidly upon UV irradiation without polymer "skin layer" formation due to a uniform decrease of pH inside the gel. Spatial control of gel shrinking was also created by irradiating UV light to a limited region of the gel through a photomask. The interface of proton diffusion ("active interface") gradually moved toward non-illuminated area. The apparent position of "active interface", however, did not change remarkably above the LCST, while protons continuously diffused outward direction. This is because the "active interface" also moved inward direction as gel shrank above the LCST. As a result, slow movement of the apparent interface was observed. The NBA-integrated gel was also successfully employed for the controlled release of an entrapped dextran in a light controlled manner. This system is highly promising as smart platforms for triggered and programmed transportation of drugs. Copyright © 2011 Elsevier B.V. All rights reserved.

Sandy soil plantation in semi-arid zones by polyacrylamide gel conditioner prepared by ionizing radiation. Part of a coordinated programme on radiation modified polymers for biomedical and biochemical applications

International Nuclear Information System (INIS)

Azzam, R.A.I.

1983-07-01

Polyacrylamide gel prepared by ionizing radiation was found to be capable of furnishing adequate conditions for sandy-soil plantation in semi-arid zones. The gel can be tailored for any soil texture under various climatic conditions. The sand-gel combination maintains three cycles of complete destruction and reformation without significant changes in erosion index. Water holding capacity and retention at different suctions in treated sand are increased. This increases water use efficiency. Fertilizers use efficiency is also increased to almost three times that of fertile clayey soil

Radiation-induced pneumothorax

International Nuclear Information System (INIS)

Epstein, D.M.; Littman, P.; Gefter, W.B.; Miller, W.T.; Raney, R.B. Jr.

1983-01-01

Pneumothorax is an uncommon complication of radiation therapy to the chest. The proposed pathogenesis is radiation-induced fibrosis promoting subpleural bleb formation that ruptures resulting in pneumothorax. We report on two young patients with primary sarcomas without pulmonary metastases who developed spontaneous pneumothorax after irradiation. Neither patient had antecedent radiographic evidence of pulmonary fibrosis

Kaempferol protects against gamma radiation-induced mortality and damage via inhibiting oxidative stress and modulating apoptotic molecules in vivo and vitro.

Science.gov (United States)

Wang, Jing; Li, Tiejun; Feng, Jingjing; Li, Li; Wang, Rong; Cheng, Hao; Yuan, Yongfang

2018-04-20

To investigate the potential protective effect of kaempferol, a representative flavonoid, against radiation induced mortality and injury in vivo and vitro.C57BL/6 male mice and human umbilical venous endothelial cells (HUVECs) were pretreated with kaempferol before radiation. We found that kaempferol can effectively increase 30-day survival rate after 8.5 Gy lethal total body irradiation (TBI). Mice were sacrificed at 7th day after 7 Gy TBI, we found kaempferol against radiation-induced tissues damage, by inhibiting the oxidative stress, and attenuating morphological changes and cell apoptosis. In vitro, kaempferol increased HUVECs cell viability and decrease apoptosis. It also mitigated oxidative stress and restored the abnormal expression of prx-5, Cyt-c, Caspase9 and Caspase3 in mRNA and protein level in HUVECs after radiation. Taken together, it suggests kaempferol can protect against gamma-radiation induced tissue damage and mortality. The present study is the first report of the radioprotective role of kaempferol in vivo and vitro. Copyright © 2018 Elsevier B.V. All rights reserved.

Protective effect of Asparagus racemosus root extract against lethal total - body electron beam radiation induced damage in Swiss albino mice

International Nuclear Information System (INIS)

Sharmila, K.P.; Bhandary, B. Satheesh Kumar; Suchetha Kumari, N.; Bhat, Vadish S.; Shetty, Jayaram; Peter, Alex John; Jose, Jerish M.; Fernandes, Ronald

2016-01-01

To investigate the protective effect of Asparagus Racemosus Root ethanolic extract (ARE) in Swiss albino mice against acute lethal total - body Electron beam irradiation. Swiss Albino mice were used for the assessment of radiation induced sickness and 30 day survival analysis. Survival studies were determined using the Kaplan-Meier survival curves. The maximum survival was observed in the experimental mice pretreated with 200 mg/kg.b.wt. of ARE which also reduced the radiation sickness characteristics. This dose was considered as an optimal dose for radioprotection. Treatment of mice with ARE before irradiation delayed the onset of mortality as compared with the untreated irradiated controls. Present findings demonstrate the potential of ARE in mitigating radiation-induced mortality, which may be attributed to its free radical scavenging and increased antioxidant potential

Radiation induced sarcomas of bone following therapeutic radiation

International Nuclear Information System (INIS)

Kim, J.H.; Chu, F.C.H.; Woodward, H.Q.; Huvos, A.

1983-01-01

Because of new therapeutic trends of multi-modality and the importance of late effects, we have updated our series of radiation induced bone sarcomas seen at Memorial Sloan-Kettering Cancer Center over the past four decades. A total of 37 cases of bone sarcoma arising from normal bone in the irradiated field was analyzed. The median for latent period from irradiation to diagnosis of bone sarcoma was 11 years with a minimum latent period of four years. The median radiation dose for the bone sarcoma was 6000 rad in 6 weeks with a minimum total radiation dose of 3000 rad in 3 weeks. We have found nine patients who developed bone sarcomas in the radiation field after successful treatment of Hodgkin's disease. Criteria for radiation induced bone sarcomas and the magnitude of the risk of bone sarcomas are briefly discussed

Development and dosimetric evaluation of radiochromic PCDA vesicle gel dosimeters

International Nuclear Information System (INIS)

Sun, P.; Fu, Y.C.; Hu, J.; Hao, N.; Huang, W.; Jiang, B.

2016-01-01

The gel dosimeter has the unique capacity in recording radiation dose distribution in three dimensions (3D), which has the specific advantages in dosimetry measurements where steep dose gradients exist, such as in intensity-modulated radiation therapy (IMRT), brachytherapy and so on. Some 3D dosimeters, such as Fricke gel dosimeters, polymer gel dosimeters, the PRESAGE plastic dosimeters and micelle gel dosimeters have appeared recently. However, there are several disadvantages of these 3D dosimeters limit their application in radiotherapy dose verification. In this study, a novel radiochromic gel dosimeter for 3D dose verification of radiotherapy was developed by dispersing nanovesicles self-assembled by 10,12-pentacosadiynoic acid (PCDA) into the tissue equivalence gel matrix. The characteristics of radiochromic PCDA vesicle gel dosimeters were evaluated. The results indicate that these radiochromic gel dosimeters have good linear dose response to X-ray irradiation in the dose range of 2–100 Gy. In addition, the radiochromic gel dosimeters breakthrough the limitations of the existing gel dosimeters such as diffusion effect, post-radiation effect, and poor forming ability. The response of the gel dosimeter does not show any dose rate dependence, energy dependence and temperature effect, and there was no obvious difference in the gel response between single and cumulative dose of fractional irradiation. Hence, the radiochromic PCDA vesicle gel dosimeters developed in this study could be generally applied to 3D dose verification in radiotherapy. - Highlights: • A novel radiochromic gel dosimeter was developed by dispersing PCDA nanovesicles into the tissue equivalence gel matrix. • This nanovesicle overcomes the dose image blurring caused by the diffusion of monomer molecules. • This nanovesicle limits the polymer chain growth, so as to reduce the post-radiation effect. • The gel matrixes possess excellent tissue equivalence and elastic strength, which

Sol/gel analysis of poly (acrylamide-co-metacrylic acid) Hydrogels obtained by gamma radiation for biomedical use

International Nuclear Information System (INIS)

Rapado, M.; Altanes, S.; Prado, S.; Chong, B.; Aguilera, Y.; Saldivar, D.

1999-01-01

Sol-Gel analysis of irradiated polymer was carried out and allowed to estimate important radiation parameters as gelation dose, virtual dose , degradation and crosslinking densities and yield of crosslinking and degradation of copolymer according with a modified Charesby-Pinner equation. The degree of copolymer conversion as a function of the absorbed dose of irradiation is presented. These parameters can be correlated with some physical and chemical properties of polymeric network formation and this way be able to design and prepare gels with the desired structure suitable as a drug delivery system

Radiation-induced bone neoplasma in facial cranium

Energy Technology Data Exchange (ETDEWEB)

Zomer-Drozda, J; Buraczewska-Lipinska, H; Buraczewski, J [Instytut Onkologii, Warsaw (Poland)

1976-01-01

Radiation-induced bone neoplasms in the region of facial cranium account for about 40% of all radiation-induced tumours of bones, although the number of cases with lesions irradiated in this area is proportionally much lower than the number of cases treated with radiotherapy in other parts of the body. Four personal cases of radiation-induced tumours with complicated course are reported. Attention is called to the value of radiological investigations in the diagnosis of bone diseases and in differential diagnosis of radiation-induced tumours of bones.

Study of the radiated energy loss during massive gas injection mitigated disruptions on EAST

Science.gov (United States)

Duan, Y. M.; Hao, Z. K.; Hu, L. Q.; Wang, L.; Xu, P.; Xu, L. Q.; Zhuang, H. D.; EAST Team

2015-08-01

The MGI mitigated disruption experiments were carried out on EAST with a new fast gas controlling valve in 2012. Different amounts of noble gas He or mixed gas of 99% He + 1% Ar are injected into plasma in current flat-top phase and current ramp-down phase separately. The initial results of MGI experiments are described. The MGI system and the radiation measurement system are briefly introduced. The characteristics of radiation distribution and radiation energy loss are analyzed. About 50% of the stored thermal energy Wdia is dissipated by radiation during the entire disruption process and the impurities of C and Li from the PFC play important roles to radiative energy loss. The amount of the gas can affect the pre-TQ phase. Strong poloidal asymmetry of radiation begins to appear in the CQ phase, which is possibly caused by the plasma configuration changes as a result of VDE. No toroidal radiation asymmetry is observed presently.

Failure modes induced by natural radiation environments on DRAM memories: study, test methodology and mitigation technique

International Nuclear Information System (INIS)

Bougerol, A.

2011-05-01

DRAMs are frequently used in space and aeronautic systems. Their sensitivity to cosmic radiations have to be known in order to satisfy reliability requirements for critical applications. These evaluations are traditionally done with particle accelerators. However, devices become more complex with technology integration. Therefore new effects appear, inducing longer and more expensive tests. There is a complementary solution: the pulsed laser, which triggers similar effects as particles. Thanks to these two test tools, main DRAM radiation failure modes were studied: SEUs (Single Event Upset) in memory blocks, and SEFIs (Single Event Functional Interrupt) in peripheral circuits. This work demonstrates the influence of test patterns on SEU and SEFI sensitivities depending on technology used. In addition, this study identifies the origin of the most frequent type of SEFIs. Moreover, laser techniques were developed to quantify sensitive surfaces of the different effects. This work led to a new test methodology for industry, in order to optimize test cost and efficiency using both pulsed laser beams and particle accelerators. Finally, a new fault tolerant technique is proposed: based on DRAM cell radiation immunity when discharged, this technique allows to correct all bits of a logic word. (author)

Regulation of radiation-induced protein kinase Cδ activation in radiation-induced apoptosis differs between radiosensitive and radioresistant mouse thymic lymphoma cell lines

International Nuclear Information System (INIS)

Nakajima, Tetsuo; Yukawa, Osami; Tsuji, Hideo; Ohyama, Harumi; Wang, Bing; Tatsumi, Kouichi; Hayata, Isamu; Hama-Inaba, Hiroko

2006-01-01

Protein kinase Cδ (PKCδ) has an important role in radiation-induced apoptosis. The expression and function of PKCδ in radiation-induced apoptosis were assessed in a radiation-sensitive mouse thymic lymphoma cell line, 3SBH5, and its radioresistant variant, XR223. Rottlerin, a PKCδ-specific inhibitor, completely abolished radiation-induced apoptosis in 3SBH5. Radiation-induced PKCδ activation correlated with the degradation of PKCδ, indicating that PKCδ activation through degradation is involved in radiation-induced apoptosis in radiosensitive 3SBH5. In radioresistant XR223, radiation-induced PKCδ activation was lower than that in radiosensitive 3SBH5. Cytosol PKCδ levels in 3SBH5 decreased markedly after irradiation, while those in XR223 did not. There was no apparent change after irradiation in the membrane fractions of either cell type. In addition, basal cytosol PKCδ levels in XR223 were higher than those in 3SBH5. These results suggest that the radioresistance in XR223 to radiation-induced apoptosis is due to a difference in the regulation of radiation-induced PKCδ activation compared to that of 3SBH5. On the other hand, Atm -/- mouse thymic lymphoma cells were more radioresistant to radiation-induced apoptosis than wild-type mouse thymic lymphoma cells. Irradiated wild-type cells, but not Atm -/- cells, had decreased PKCδ levels, indicating that the Atm protein is involved in radiation-induced apoptosis through the induction of PKCδ degradation. The decreased Atm protein levels induced by treatment with Atm small interfering RNA had no effect on radiation-induced apoptosis in 3SBH5 cells. These results suggest that the regulation of radiation-induced PKCδ activation, which is distinct from the Atm-mediated cascade, determines radiation sensitivity in radiosensitive 3SBH5 cells

Radiation-induced Changes in the Electrophoretic Profile of Serum Albumin

Directory of Open Access Journals (Sweden)

Celso Vieira Lima

2018-01-01

Full Text Available ABSTRACT Albumin protein profiles were investigated in electrophoresis system in relation to the whole body exposition to the radiation. Two groups of rats Wistar were set up as the control (CG and the irradiated one (IG. The IG was exposed to Co-60 at a dose of 5 Gy. After a 72-hour exposition, 300 μL of blood was collected in the inferior vena cava, renal, jugular, hepatic, and pulmonary veins and the serum separated. The albumin protein was identified by vertical electrophoresis in acrylamide Commassi blue or silver stained. The calibration procedure was applied to albumin samples with well-known concentrations. The mathematical correlation was developed involving electrophoretic parameters of band intensities and sizes from gel representation, providing values of protein concentrations in comparison with standard bands with known concentrations. There were significant differences in the physiological concentrations in the jugular and pulmonary sites in relation to renal and cava regional sites. Significant differences induced by radiation in serum albumin concentration were also found in hepatic and jugular sites. Alteration of albumin concentration was found as a nearly effect from whole body irradiation. This phenomenon points out to alterations in cell metabolism in the liver justified by a possible indication of proteomics damage from radiation.

3 cases of radiation-induced sarcoma

International Nuclear Information System (INIS)

Shiba, Keiichiro; Fukuma, Hisatoshi; Beppu, Yasuo; Hirota, Teruyuki; Shinohara, Norio.

1982-01-01

Criteria for the diagnosis of radiation-induced sarcoma have been previously described. All cases must have a history of irradiation and the second neoplasm must have arisen in the area of the radiation field. A latent period of several years must have elapsed after irradiation before clinical evidence of a second malignant neoplasm. Most important thing is that, all suspected cases must have been proved histologically. We have experienced 3 cases of radiation-induced sarcoma, they were 42-years-old man who developed an osteosarcoma of the lumbar spine at the field of postoperative irradiation for seminoma 7 years previously, 69-years-old woman who developed a malignant fibrous histiocytoma of the buttock at the field of radical radiation for uterine carcinoma 7 years previously and 59-years-old woman who developed an extraskeletal osteosarcoma of the abdominal wall at the field of postoperative irradiation for uterine sarcoma 7 years previously. The last case is very rare and only 8 cases of radiation-induced extraskeletal osteosarcoma have been reported. Since there has been a definite trend in the treatment of cancer toward employing radiation for more favorable cases, in addition to technical improvements in the administration of radiotherapy and more modern equipment, survival data may have been altered considerably in many malignant tumors. Accordingly, more radiation-induced tumors may be encountered in the future. The clinical presentation and histopathology of these radiation-induced sarcomas are presented with a review of the literature. (author)

The effect of carbohydrates and lipids on the radiation-induced aggregation of proteins

International Nuclear Information System (INIS)

Delincee, H.; Jakubick, V.

1977-01-01

Myoglobin, ovalbumin and serum albumin have been irradiated in aqueous solution in the presence of varying amounts of carbohydrates and lipids, simulating a model food. Gel chromatography revealed the induction of protein aggregates, the formation of which depended strongly on protein concentration. The addition of carbohydrates (trehalose, starch) greatly reduced the amount of radiation-induced aggregates, whereas the addition of lipids (sunflower oil) had practically no effect on aggregate formation. However, if both carbohydrates and lipids were added, the decrease in aggregation caused by the carbohydrate addition was counteracted by the addition of the lipid; as increasing amounts of lipid were added, the effect of carbohydrate addition became smaller. (author)

Mitigation of Unwanted Forward Narrow-band Radiation from PCBs with a Metamaterial Unit Cell

DEFF Research Database (Denmark)

Ruaro, Andrea; Thaysen, Jesper; Jakobsen, Kaj Bjarne

2013-01-01

Mitigation of EMI from a PCB is obtained through the use of a metamaterial unit cell. The focus is on the reduction of narrow-band radiation in the forward hemisphere when the resonant element is etched on a layer located between the source of radiation and the ground plane. As opposed to previous...... publications in the literature, the aim of this work is the application of a filter to scattered radiation, generalizing the former characterizations based solely upon transmission lines’ insertion loss. The radiating area accounts for traces and components placed on the top layer of a PCB and is simulated via...... a patch antenna. The study exhibits how the radiation pattern and the electric field on the patch antenna change within and outside the resonance bandwidth of the parasitic element. An EMC assessment provides experimental verification of the operating principle....

Placebo effect of an inert gel on experimentally induced leg muscle pain

Directory of Open Access Journals (Sweden)

James G Hopker

2010-11-01

Full Text Available James G Hopker1, Abigail J Foad2, Christopher J Beedie2, Damian A Coleman2, Geoffrey Leach11Centre for Sports Studies, University of Kent, Chatham, Kent, UK; 2Department of Sports Science, Tourism and Leisure, Canterbury Christ Church University, Canterbury, Kent, UKPurpose: This study examined the therapeutic effects of an inert placebo gel on experimentally induced muscle pain in a sports therapy setting. It aimed to investigate the degree to which conditioned analgesia, coupled with an expectation of intervention, was a factor in subsequent analgesia.Methods: Participants were sixteen male and eight female sports therapy students at a UK University. With institutional ethics board approval and following informed consent procedures, each was exposed to pain stimulus in the lower leg in five conditions, ie, conditioning, prebaseline, experimental (two placebo gel applications, and postbaseline. In conditioning trials, participants identified a level of pain stimulus equivalent to a perceived pain rating of 6/10. An inert placebo gel was then applied to the site with the explicit instruction that it was an analgesic. Participants were re-exposed to the pain stimulus, the level of which, without their knowledge, had been decreased, creating the impression of an analgesic effect resulting from the gel. In experimental conditions, the placebo gel was applied and the level of pain stimulus required to elicit a pain rating of 6/10 recorded.Results: Following application of the placebo gel, the level of pain stimulus required to elicit a pain rating of 6/10 increased by 8.2%. Application of the placebo gel significantly decreased participant’s perceptions of muscle pain (P = 0.001.Conclusion: Subjects’ experience and expectation of pain reduction may be major factors in the therapeutic process. These factors should be considered in the sports therapeutic environment.Keywords: conditioning, expectation, perception, positive belief, sports therapy

Gamma-radiation induced synthesis of silver nanoparticles in gelatin and its application for radiotherapy dose measurements

Science.gov (United States)

Soliman, Y. S.

2014-09-01

A new gel dosimeter based on a radiation-sensitive silver nitrate was formulated and investigated for its potential use in γ-radiation treatment, from 3 to 100 Gy. This gel matrix is analyzed by UV-vis spectrophotometry and X-ray diffraction (XRD). Subjecting the gel to γ-rays produces Ag nanoparticles that exhibit a plasmon resonance absorption band at 450 nm. The intensity of this band increases linearly with the increase of absorbed dose up to 100 Gy. Stability of Ag nanoparticle in the dark at 6 °C is good. The overall uncertainty (2σ) of the gel dosimeter is estimated as ~4.65% in the dose range of 5-100 Gy.

Investigation of the use of FXG gel dosimeter for UV radiation detection

International Nuclear Information System (INIS)

Bero, M.; Abu Kassem, I.

2009-02-01

The radio-chromic chemical radiation dosimeter is well known type of detectors that have been used in the measurement application of radiation dose resulting for ionizing radiation such as γ and X-rays. The detector materials consist of mainly water with added gelatin powder that gives the detector its solid shape. Other chemicals sensitive to radiation are also added to form the Ferrous-sulfate Xylenol-orange Gelatin gel detector (FXG). Ionizing radiation effects appears as an increase in the optical absorbance within a defined range of wavelengths located in the visible region of the light spectrum. These visible changes in the materials optical characteristic as a result of radiation exposure is proportional to the radiation absorbed dose at certain wave lengths. Ultraviolet radiation was found to produce similar effects in the FXG detector materials; hence we suggested studying the UV effects in details. It is known that UV radiation carry relatively high quantum energies big enough to enhance important chemical and biological reactions in some exposed medium. This study examines the most important properties required for the FXG detector to be used as a UV monitoring system that is capable of measuring the absorbed UV radiation dose. The study also works on finding chemical detector structure that is easy to be used for simulating the UV interactions with human body. It has been shown that the optical absorbance of standard size FXG samples increases linearly with the exposure time to UV radiation produced by a sun simulator source, when the beam is filtered to produces exposure similar to that found in nature. However, the UV effects are also influenced by the applied UV radiation spectrum used for irradiation as well as the thicknesses of the FXG materials.(authors)

Assessment of DNA damage in radiation workers by using single cell gel electrophoresis

International Nuclear Information System (INIS)

Jia Lili; Zhang Tao; Yang Yonghua; Wang Yan; Du Liqing; Cao Jia; Wang Hong; Liu Qiang; Fan Feiyue

2010-01-01

Objective: To assess the DNA damage of radiation workers in different grade hospitals, and to explore the correlation between the types of work or work time and the levels of DNA damage. Methods: DNA single strand break were detected by using alkaline single cell gel electrophoresis (SCGE), and the comet was analyzed with CASP (Comet Assay Software Project). TDNA%, TL, TM and OTM were calculated. Results: The parameters of SCGE in the radiation group were higher than those of control group (F=3.93, P<0.01). The significant difference was found not only among the different types of work or different work time, but also among the different grade hospitals (F=1.83, 1.91, P<0.05). Conclusions: Various levels of DNA damage could be detected in the radiation workers of the two hospitals. DNA damage of radiation workers is less serious in the higher-grade hospital than the lower grade one. Different types of work or work time might affect the DNA damage level. (authors)

Radiation-induced radical ions in calcium sulfite

Science.gov (United States)

Bogushevich, S. E.

2006-07-01

We have used EPR to study the effect of γ radiation on calcium sulfite. We have observed and identified the radiation-induced radical ions SO 2 - (iso) with g = 2.0055 and SO 2 - (orth-1) with g1 = 2.0093, g2 = 2.0051, g3 = 2.0020, identical to the initial and thermally induced SO 2 - respectively, SO 3 - (iso) with g = 2.0031 and SO 3 - (axial) with g⊥ = 2.0040, g∥ = 2.0023, identical to mechanically induced SO 3 - . We have established the participation of radiation-induced radical ions SO 3 - in formation of post-radiation SO 2 - .

Sol-Gel Glasses

Science.gov (United States)

Mukherjee, S. P.

1985-01-01

Multicomponent homogeneous, ultrapure noncrystalline gels/gel derived glasses are promising batch materials for the containerless glass melting experiments in microgravity. Hence, ultrapure, homogeneous gel precursors could be used to: (1) investigate the effect of the container induced nucleation on the glass forming ability of marginally glass forming compositions; and (2) investigate the influence of gravity on the phase separation and coarsening behavior of gel derived glasses in the liquid-liquid immiscibility zone of the nonsilicate systems having a high density phase. The structure and crystallization behavior of gels in the SiO2-GeO2 as a function of gel chemistry and thermal treatment were investigated. As are the chemical principles involved in the distribution of a second network former in silica gel matrix being investigated. The procedures for synthesizing noncrystalline gels/gel-monoliths in the SiO2-GeO2, GeO2-PbO systems were developed. Preliminary investigations on the levitation and thermal treatment of germania silicate gel-monoliths in the Pressure Facility Acoustic Levitator were done.

New radiation mitigators to reduce bone marrow death of mice by post-irradiation administration

International Nuclear Information System (INIS)

Anzai, Kazunori

2009-01-01

We have found recently that heat-treated mineral yeast preparations and water-soluble analogs of vitamin E are potent radiation mitigator to reduce bone marrow death of mice by post-irradiation administration. When administered immediately after whole-body X-irradiation (7.5 Gy), both Zn-yeast and γ-tocopherol dimethylglycine ester (TDMG) significantly increased the viability of mice from 0% (control) to more than 90% (treated). Zn-yeast did not inhibit the tumor-regulation by γ-rays but even sensitize the radiation effect in mice xenografts of HeLa cells. (author)

Radiation- induced aneuploidy in mammalian germ cells

International Nuclear Information System (INIS)

Tease, C.

1989-01-01

The ability of ionizing radiation to induce aneuploidy in mammalian germ cells has been investigated experimentally in the laboratory mouse using a variety of cytogenetic and genetic methods. These studies have provided unambiguous evidence of induced nondisjunction in both male and female germ cells when the effect of irradiation is screened in meiotic cells or preimplantation embryos. In contrast, however, cytogenetic analyses of post-implantation embryos and genetic assays for induced chromosome gains have not found a significant radiation effect. These apparently contradictory findings may be reconciled if (a) radiation induces tertiary rather than primary trisomy, or (b) induces embryo-lethal genetic damage, such as deletions, in addition to numerical anomalies. Either or both of these explanations may account for the apparent loss during gestation of radiation-induced trisomic embryos. Extrapolating from the information so far available, it seems unlikely that environmental exposure to low doses if low dose rate radiation will result in a detectable increase in the rate of aneuploidy in the human population. (author)

Radiation-induced camptocormia and dropped head syndrome. Review and case report of radiation-induced movement disorders

Energy Technology Data Exchange (ETDEWEB)

Seidel, Clemens; Kuhnt, Thomas; Kortmann, Rolf-Dieter; Hering, Kathrin [Leipzig University, Department of Radiotherapy and Radiation Oncology, Leipzig (Germany)

2015-10-15

In recent years, camptocormia and dropped head syndrome (DHS) have gained attention as particular forms of movement disorders. Camptocormia presents with involuntary forward flexion of the thoracolumbar spine that typically increases during walking or standing and may severely impede walking ability. DHS is characterized by weakness of the neck extensors and a consecutive inability to extend the neck; in severe cases the head is fixed in a ''chin to chest position.'' Many diseases may underlie these conditions, and there have been some reports about radiation-induced camptocormia and DHS. A PubMed search with the keywords ''camptocormia,'' ''dropped head syndrome,'' ''radiation-induced myopathy,'' ''radiation-induced neuropathy,'' and ''radiation-induced movement disorder'' was carried out to better characterize radiation-induced movement disorders and the radiation techniques involved. In addition, the case of a patient developing camptocormia 23 years after radiation therapy of a non-Hodgkin's lymphoma of the abdomen is described. In total, nine case series of radiation-induced DHS (n = 45 patients) and - including our case - three case reports (n = 3 patients) about radiogenic camptocormia were retrieved. Most cases (40/45 patients) occurred less than 15 years after radiotherapy involving extended fields for Hodgkin's disease. The use of wide radiation fields including many spinal segments with paraspinal muscles may lead to radiation-induced movement disorders. If paraspinal muscles and the thoracolumbar spine are involved, the clinical presentation can be that of camptocormia. DHS may result if there is involvement of the cervical spine. To prevent these disorders, sparing of the spine and paraspinal muscles is desirable. (orig.) [German] In den letzten Jahren haben Bewegungsstoerungen von Wirbelsaeule und paraspinaler Muskulatur in

Radiation-induced myelopathy

Energy Technology Data Exchange (ETDEWEB)

Gaenshirt, H [Heidelberg Univ. (F.R. Germany). Neurologische Klinik

1975-10-01

12 cases of radiation-induced myelopathy after /sup 60/Co teletherapy are reported on. Among these were 10 thoracal lesions, one cerviothoracal lesion, and one lesion of the medulla oblongata. In 9 cases, Hodgkin's disease had been the primary disease, tow patients had been irradiated because of suspected vertebral metastases of cancer of the breast, and one patient had suffered from a glomus tumour of the petrous bone. The spinal doses had exceeded the tolerance doses recommended in the relevant literature. There was no close correlation between the radiation dose and the course of the disease. The latency periods between the end of the radiotherapy and the onset of the neurological symptons varied from 6 to 16 mouths and were very constant in 7 cases with 6 to 9 months. The segmental height of the lesion corresponded to the level of irradiation. The presenting symptons of radiation-induced myelopathy are buruing dysaesthesias and Brown-Sequard's paralysis which may develop into transverse lesion of the cord with paraplegia still accompanied by dissociated perception disorders. The disease developed intermittently. Disturbances of the bladder function are frequent. The fluid is normal in most cases. Myelographic examinations were made in 8 cases. 3 cases developed into stationary cases exhibiting. Brown-Sequard syndrome, while 9 patients developed transverse lesion of the cord with paraplegia. 3 patients have died; antopsy findings are given for two of these. In the pathogenesis of radiation-induced myelopathy, the vascular factor is assumed to be of decisive importance.

Dosimetric evaluation of spectrophotometric response of alanine gel solution for gamma, photons, electrons and thermal neutrons radiations; Avaliacao dosimetrica da resposta espectrofotometrica da solucao gel de alanina para radiacao gama, de fotons, de eletrons e de neutrons termicos

Energy Technology Data Exchange (ETDEWEB)

Silva, Cleber Feijo

2009-07-01

Alanine Gel Dosimeter is a new gel material developed at IPEN that presents significant improvement on Alanine system developed by Costa. The DL-Alanine (C{sub 3}H{sub 7}NO{sub 2}) is an amino acid tissue equivalent that improves the production of ferric ions in the solution. This work aims to analyse the main dosimetric characteristics this new gel material for future application to measure dose distribution. The performance of Alanine gel solution was evaluated to gamma, photons, electrons and thermal neutrons radiations using the spectrophotometry technique. According to the obtained results for the different studied radiation types, the reproducibility intra-batches and inter-batches is better than 4% and 5%, respectively. The dose response presents a linear behavior in the studied dose range. The response dependence as a function of dose rate and incident energy is better 2% and 3%, respectively. The lower detectable dose is 0.1 Gy. The obtained results indicate that the Alanine gel dosimeter presents good performance and can be useful as an alternative dosimeter in the radiotherapy area, using MRI technique for tridimensional dose distribution evaluation. (author)

Radiation-induced genomic instability and bystander effects: related inflammatory-type responses to radiation-induced stress and injury? A review.

Science.gov (United States)

Lorimore, S A; Wright, E G

2003-01-01

To review studies of radiation responses in the haemopoietic system in the context of radiation-induced genomic instability, bystander effects and inflammatory-type processes. There is considerable evidence that cells that themselves are not exposed to ionizing radiation but are the progeny of cells irradiated many cell divisions previously may express a high frequency of gene mutations, chromosomal aberrations and cell death. These effects are collectively known as radiation-induced genomic instability. A second untargeted effect results in non-irradiated cells exhibiting responses typically associated with direct radiation exposure but occurs as a consequence of contact with irradiated cells or by receiving soluble signals from irradiated cells. These effects are collectively known as radiation-induced bystander effects. Reported effects include increases or decreases in damage-inducible and stress-related proteins; increases or decreases in reactive oxygen species, cell death or cell proliferation, and induction of mutations and chromosome aberrations. This array of responses is reminiscent of effects mediated by cytokines and other similar regulatory factors that may involve, but do not necessarily require, gap junction-mediated transfer, have multiple inducers and a variety of context-dependent consequences in different cell systems. That chromosomal instability in haemopoietic cells can be induced by an indirect bystander-type mechanism both in vitro and in vivo provides a potential link between these two untargeted effects and there are radiation responses in vivo consistent with the microenvironment contributing secondary cell damage as a consequence of an inflammatory-type response to radiation-induced injury. Intercellular signalling, production of cytokines and free radicals are features of inflammatory responses that have the potential for both bystander-mediated and persisting damage as well as for conferring a predisposition to malignancy. The

Radiation-induced polymerization and radiation effect on polymers

International Nuclear Information System (INIS)

Seguchi, Tadao

1977-12-01

The processes of radiation-induced polymerization of monomers and also radiation effects on polymers have been studied by instrumental analyses of electron spin resonance (ESR), nuclear magnetic resonance (NMR) and electron microscopy. In radiation-induced polymerization, graft-copolymerization and absorbed state polymerization were taken up. For graft-copolymerization, monomers such as methylmethacrylate and butadiene were made to react with irradiated polyethylene, and behaviors of the initiating radicals and propagating radicals were followed under the reaction by ESR. For absorbed state polymerization, acrylonitrile/zeolite and methylmethacrylate/zeolite were chosen. Absorbed monomers were irradiated at 77 0 K and polymerized at room temperature. Active species and the concentrations were measured by ESR and the yields of polymer were observed by NMR. In radiation effect on polymers, polyvinylfluoride, polyvinylidenfluoride and polytetrafluoroethylene were taken up. Active species trapped in the polymer matrixes were identified and decay and reactivity of the species were also studied. On the basis of information from the electron microscopy and x-ray analysis, radiation effects on these polymers are described. In polytetrafluoroethylene produced by radiation polymerization, the relation between morphology and polymerization conditions and also the process of crystallization during polymerization were studied. (auth.)

Study on radiation-inducible genes

Energy Technology Data Exchange (ETDEWEB)

Lim, Sang Yong; Kim, Dong Ho; Joe, Min Ho; Park, Hae Jun; Song, Hyu Npa

2012-01-15

Radiation-inducible genes of E. coli, which is a model strain for bacterial study, and Salmonella, which is a typical strain for pathogenic bacteria were compared through omic analysis. Heat shock response genes and prophage genes were induced by radiation in Salmonella, not in E. coli. Among prophage genes tested, STM2628 showed the highest activation by radiation, and approximately 1 kb promoter region was turned out to be necessary for radiation response. To screen an artificial promoter showing activation by 2 Gy, the high-throughput screening method using fluorescent MUG substrate was established. The use of bacteria as anticancer agents has attracted interest. In this study, we tried to develop tumor targeting bacteria in which the radiation-inducible promoter activate a transgene encoding a cytotoxic protein. To do this, a tumor-targeting hfq Salmonella mutant strain was constructed, and we found that its virulence decreased. For outward secretion of anticancer protein produced inside bacteria, the signal peptide of SspH1 was determined and the signal peptide was proven to be able to secrete an anticancer protein. Tumor xenograft mouse model was secured, which can be used for efficiency evaluation of bacterial tumor therapy.

Study on radiation-inducible genes

International Nuclear Information System (INIS)

Lim, Sang Yong; Kim, Dong Ho; Joe, Min Ho; Park, Hae Jun; Song, Hyu Npa

2012-01-01

Radiation-inducible genes of E. coli, which is a model strain for bacterial study, and Salmonella, which is a typical strain for pathogenic bacteria were compared through omic analysis. Heat shock response genes and prophage genes were induced by radiation in Salmonella, not in E. coli. Among prophage genes tested, STM2628 showed the highest activation by radiation, and approximately 1 kb promoter region was turned out to be necessary for radiation response. To screen an artificial promoter showing activation by 2 Gy, the high-throughput screening method using fluorescent MUG substrate was established. The use of bacteria as anticancer agents has attracted interest. In this study, we tried to develop tumor targeting bacteria in which the radiation-inducible promoter activate a transgene encoding a cytotoxic protein. To do this, a tumor-targeting hfq Salmonella mutant strain was constructed, and we found that its virulence decreased. For outward secretion of anticancer protein produced inside bacteria, the signal peptide of SspH1 was determined and the signal peptide was proven to be able to secrete an anticancer protein. Tumor xenograft mouse model was secured, which can be used for efficiency evaluation of bacterial tumor therapy

Radiation-induced cancers in man

International Nuclear Information System (INIS)

Hirose, Fumio

1978-01-01

Radiation-induced cancers in man were divided into three groups, a group in which cancers occurred after atomic bomb exposure, a group in which cancers occurred in radiologists and other medical specialists, and a group in which cancers occurred after exposure to diagnostic radiation, and they were summarized. In atomic bomb survivors leukemia, thyroid cancer, salivary gland cancer, lung cancer, and breast cancer occurred so frequently. In addition to them, mortality ratios by malignant lymphoma, stomach cancer, esophageal cancer, and by cancer of urinary tract were increased. The incidence of leukemia was decreased in those who treated radiation owing to the development of the protection of occupational exposure, and the incidence of radiation-induced cancers was decreased in patients owing to the improvement of therapy. However, a new problem has arisen as to the occurrence of cancers after medical exposure, such as various histological types of cancers after the treatment of skin diseases on the head, and breast cancer after the treatment of pneumothorax. Dose-to-effect relation, hereditary factors, effect of age, immunological influences and endocrine actions were also studied in each radiation-induced cancer. (Ichikawa, K.)

Radiation-induced cancers in man

Energy Technology Data Exchange (ETDEWEB)

Hirose, F [Hiroshima Univ. (Japan). Research Inst. for Nuclear Medicine and Biology

1978-07-01

Radiation-induced cancers in man were divided into three groups, a group in which cancers occurred after atomic bomb exposure, a group in which cancers occurred in radiologists and other medical specialists, and a group in which cancers occurred after exposure to diagnostic radiation, and they were summarized. In atomic bomb survivors leukemia, thyroid cancer, salivary gland cancer, lung cancer, and breast cancer occurred so frequently. In addition to them, mortality ratios by malignant lymphoma, stomach cancer, esophageal cancer, and by cancer of urinary tract were increased. The incidence of leukemia was decreased in those who treated radiation owing to the development of the protection of occupational exposure, and the incidence of radiation-induced cancers was decreased in patients owing to the improvement of therapy. However, a new problem has arisen as to the occurrence of cancers after medical exposure, such as various histological types of cancers after the treatment of skin diseases on the head, and breast cancer after the treatment of pneumothorax. Dose-to-effect relation, hereditary factors, effect of age, immunological influences and endocrine actions were also studied in each radiation-induced cancer.

Mitigation of waterlogging-induced damages to pepper by exogenous meja

International Nuclear Information System (INIS)

Jun, O.; Bin, L.; Zhi, Y.B.

2017-01-01

In this study, we studied the mitigation effects of exogenous Methyl jasmonate (MeJA) on waterlogging-induced damages to Xinyou No.5 wrinkled skin pepper cultivar by spraying MeJA on leave's surface at different waterlogging periods and investigated its underlying mechanisms. The results showed that administration of MeJA increased antioxidant enzymes' activities, proline and soluble sugar contents and alcohol dehydrogenase (ADH) activity, reduced relative conductivity, malondialdehyde (MDA) and hydroxyl free radical (.OH) accumulation, lactate dehydrogenase (LDH) activity and lactic acid and acetaldehyde accumulation, and maintained high root malate dehydrogenase (MDH) and succinate dehydrogenase (SDH) activities and certain aerobic respiratory metabolism. The study also found that there were significant differences among exogenous MeJA treatments at different waterlogging periods. Peppers treated with exogenous MeJA 1 day and 2 days prior to waterlogging had optimal agronomic traits, higher chlorophyll content, enzymatic activities and osmolytic substances, as well as lower relative conductivity, MDA and ·OH accumulation. Overall, the results suggest that MeJA mitigates waterlogging-induced damages to pepper by adjusting osmolytic substances contents, antioxidant enzymatic activities and root respiration and metabolism and achieves better alleviation effects by spraying prior to waterlogging. (author)

Radiation-induced brain injury: A review

Directory of Open Access Journals (Sweden)

Michael eRobbins

2012-07-01

Full Text Available Approximately 100,000 primary and metastatic brain tumor patients/year in the US survive long enough (> 6 months to experience radiation-induced brain injury. Prior to 1970, the human brain was thought to be highly radioresistant; the acute CNS syndrome occurs after single doses > 30 Gy; white matter necrosis occurs at fractionated doses > 60 Gy. Although white matter necrosis is uncommon with modern techniques, functional deficits, including progressive impairments in memory, attention, and executive function have become important, because they have profound effects on quality of life. Preclinical studies have provided valuable insights into the pathogenesis of radiation-induced cognitive impairment. Given its central role in memory and neurogenesis, the majority of these studies have focused on the hippocampus. Irradiating pediatric and young adult rodent brains leads to several hippocampal changes including neuroinflammation and a marked reduction in neurogenesis. These data have been interpreted to suggest that shielding the hippocampus will prevent clinical radiation-induced cognitive impairment. However, this interpretation may be overly simplistic. Studies using older rodents, that more closely match the adult human brain tumor population, indicate that, unlike pediatric and young adult rats, older rats fail to show a radiation-induced decrease in neurogenesis or a loss of mature neurons. Nevertheless, older rats still exhibit cognitive impairment. This occurs in the absence of demyelination and/or white matter necrosis similar to what is observed clinically, suggesting that more subtle molecular, cellular and/or microanatomic modifications are involved in this radiation-induced brain injury. Given that radiation-induced cognitive impairment likely reflects damage to both hippocampal- and non-hippocampal-dependent domains, there is a critical need to investigate the microanatomic and functional effects of radiation in various brain

Radiation tolerance and mitigation strategies for FPGA:s in the ATLAS TileCal Demonstrator

CERN Document Server

Akerstedt, H; The ATLAS collaboration

2013-01-01

During 2014, demonstrator electronics will be installed in a Tile calorimeter "drawer" to get long term experience with the inherently redundant electronics proposed for a full upgrade scheduled for 2022. The new system, being FPGA-based, uses dense programmable logic which must be proven to be sufficently radiation tolerant. It must be protected against radiation induced single event upsets that corrupt memory and logic functions. Radiation induced errors need to be found and compensated for in time, to minimize data loss but also to avoid permanent damage. Strategies for detecting and correcting radiation induced errors in the Kintex-7 FPGA:s of the demonstrator are evaluated and discussed.

Radiation tolerance and mitigation strategies for FPGA:s in the ATLAS TileCal Demonstrator

CERN Document Server

Akerstedt, H; The ATLAS collaboration; Drake, G; Muschter, S; Oreglia, M; Tang, F; Anderson, K; Paramonov, A

2013-01-01

During 2014, upgrade-demonstrator electronics will be installed in a Tile calorimeter drawer to obtain long term experience with the inherently redundant electronics proposed for a full upgrade scheduled for 2022. The new, FPGA-based system uses dense programmable logic, which must be proven to be sufficiently radiation tolerant. It must also be protected against radiation induced single event upsets that can corrupt memory and logic Radiation induced errors need to be found and compensated for in time to minimize data loss, and also to avoid permanent damage. Strategies for detecting and correcting radiation induced errors in the Kintex-7 FPGAs on the demonstrator electronics are evaluated and discussed.

Radiation reaction of skin treatment with nucliderm-gel

International Nuclear Information System (INIS)

Pandova, V.; Marinova, Ts.; Stefanova, D.; Pantev, T.; Yankova, S.

1988-01-01

The process of epithelization and the anticeptic effect of nucliderm-gel applied locally have been studied in 63 oncological patients subjected to radiotherapy. In all cases under study nucliderm-gel promotes skin epithelization and has a high antiseptic effect as compared with the drugs applied hitherto

Ionizing radiation induced malignancies in man

International Nuclear Information System (INIS)

Dutrillaux, B.

1997-01-01

Using data on gene and chromosome alterations in human cancers, it is proposed that most radiation induced cancers are a consequence of recessive mutations of tumor suppressor genes. This explains the long delay between radiation exposure and the cancer onset. As a consequence, radiation induced cancers belong to groups of tumors where no specific translocations (forming or activating oncogenes) but multiple unbalanced chromosome rearrangements (deletions unmasking recessive mutations) exist. This explains why osteosarcomas, malignant fibrous histiocytoma, chondrosarcomas are frequently induced, but not liposarcoma, Ewing sarcomas and rhabdomyosarcomas, among others. A single exception confirms this rule: papillary thyroid cancer, frequently induced in exposed children, in which structural rearrangements frequently form a RET/PTC3 fusion gene. This fusion gene is the results of the inversion of a short segment of chromosome 10, and it is assumed that such rearrangement (small para-centric inversion) can easily occur after exposure to radiations, at contrast with translocations between to genes belonging to different chromosomes. (author)

Prototype Biology-Based Radiation Risk Module Project

Science.gov (United States)

Terrier, Douglas; Clayton, Ronald G.; Patel, Zarana; Hu, Shaowen; Huff, Janice

2015-01-01

Biological effects of space radiation and risk mitigation are strategic knowledge gaps for the Evolvable Mars Campaign. The current epidemiology-based NASA Space Cancer Risk (NSCR) model contains large uncertainties (HAT #6.5a) due to lack of information on the radiobiology of galactic cosmic rays (GCR) and lack of human data. The use of experimental models that most accurately replicate the response of human tissues is critical for precision in risk projections. Our proposed study will compare DNA damage, histological, and cell kinetic parameters after irradiation in normal 2D human cells versus 3D tissue models, and it will use a multi-scale computational model (CHASTE) to investigate various biological processes that may contribute to carcinogenesis, including radiation-induced cellular signaling pathways. This cross-disciplinary work, with biological validation of an evolvable mathematical computational model, will help reduce uncertainties within NSCR and aid risk mitigation for radiation-induced carcinogenesis.

Joint immobilization inhibits spontaneous hyaline cartilage regeneration induced by a novel double-network gel implantation.

Science.gov (United States)

Arakaki, Kazunobu; Kitamura, Nobuto; Kurokawa, Takayuki; Onodera, Shin; Kanaya, Fuminori; Gong, Jian-Ping; Yasuda, Kazunori

2011-02-01

We have recently discovered that spontaneous hyaline cartilage regeneration can be induced in an osteochondral defect in the rabbit, when we implant a novel double-network (DN) gel plug at the bottom of the defect. To clarify whether joint immobilization inhibits the spontaneous hyaline cartilage regeneration, we conducted this study with 20 rabbits. At 4 or 12 weeks after surgery, the defect in the mobile knees was filled with a sufficient volume of the hyaline cartilage tissue rich in proteoglycan and type-2 collagen, while no cartilage tissues were observed in the defect in the immobilized knees. Type-2 collagen, Aggrecan, and SOX9 mRNAs were expressed only in the mobile knees at each period. This study demonstrated that joint immobilization significantly inhibits the spontaneous hyaline cartilage regeneration induced by the DN gel implantation. This fact suggested that the mechanical environment is one of the significant factors to induce this phenomenon.

Three cases of radiation-induced cancer in oral regions

International Nuclear Information System (INIS)

Kawamura, Hiroshi; Shinoki, Kunihiko; Endo, Yoshitaka; Fujita, Yasushi; Hayashi, Susumu

1985-01-01

Three cases of radiation-induced cancer in the oral regions were reported with relation to radiation therapy. One was the general radiation-induced cancer following radiotherapy for the hemangioma. The other two cases, which belonged in the B-1 group of Sakai and his coworker's diagnostic criteria for radiation-induced cancer, were those occurring after radiotherapy for the malignant tumors. Due to the relatively high dosage exposure by the patient in the radiotherapy it is necessary to look out the latency of the radiation-induced cancer. After radiotherapy, careful and periodical observation is important for immediate treatment in an early stage for the radiation-induced cancer to have a favorable prognosis. In addition careful observation of the changes after radiotherapy helps in discovering the precancerous lesions from the therapy. For the radiation-induced cancer, surgical treatment would be the best, however, radiation therapy is also effective in certain cases. (author)

Dosimetric evaluation of a novel polymer gel dosimeter for proton therapy

Energy Technology Data Exchange (ETDEWEB)

Zeidan, O. A.; Sriprisan, S. I.; Lopatiuk-Tirpak, O.; Kupelian, P. A.; Meeks, S. L.; Hsi, W. C.; Li, Z.; Palta, J. R.; Maryanski, M. J. [M. D. Anderson Cancer Center Orlando, Orlando, Florida 32806 (United States); University of Florida Proton Therapy Institute, Jacksonville, Florida 32206 (United States); MGS Research, Inc., Madison, Connecticut 06443 (United States)

2010-05-15

Purpose: The aim of this study is to evaluate the dosimetric performance of a newly developed proton-sensitive polymer gel formulation for proton therapy dosimetry. Methods: Using passive scattered modulated and nonmodulated proton beams, the dose response of the gel was assessed. A next-generation optical CT scanner is used as the readout mechanism of the radiation-induced absorbance in the gel medium. Comparison of relative dose profiles in the gel to ion chamber profiles in water is performed. A simple and easily reproducible calibration protocol is established for routine gel batch calibrations. Relative stopping power ratio measurement of the gel medium was performed to ensure accurate water-equivalent depth dose scaling. Measured dose distributions in the gel were compared to treatment planning system for benchmark irradiations and quality of agreement is assessed using clinically relevant gamma index criteria. Results: The dosimetric response of the gel was mapped up to 600 cGy using an electron-based calibration technique. Excellent dosimetric agreement is observed between ion chamber data and gel. The most notable result of this work is the fact that this gel has no observed dose quenching in the Bragg peak region. Quantitative dose distribution comparisons to treatment planning system calculations show that most (>97%) of the gel dose maps pass the 3%/3 mm gamma criterion. Conclusions: This study shows that the new proton-sensitive gel dosimeter is capable of reproducing ion chamber dose data for modulated and nonmodulated Bragg peak beams with different clinical beam energies. The findings suggest that the gel dosimeter can be used as QA tool for millimeter range verification of proton beam deliveries in the dosimeter medium.

Dosimetric evaluation of a novel polymer gel dosimeter for proton therapy

International Nuclear Information System (INIS)

Zeidan, O. A.; Sriprisan, S. I.; Lopatiuk-Tirpak, O.; Kupelian, P. A.; Meeks, S. L.; Hsi, W. C.; Li, Z.; Palta, J. R.; Maryanski, M. J.

2010-01-01

Purpose: The aim of this study is to evaluate the dosimetric performance of a newly developed proton-sensitive polymer gel formulation for proton therapy dosimetry. Methods: Using passive scattered modulated and nonmodulated proton beams, the dose response of the gel was assessed. A next-generation optical CT scanner is used as the readout mechanism of the radiation-induced absorbance in the gel medium. Comparison of relative dose profiles in the gel to ion chamber profiles in water is performed. A simple and easily reproducible calibration protocol is established for routine gel batch calibrations. Relative stopping power ratio measurement of the gel medium was performed to ensure accurate water-equivalent depth dose scaling. Measured dose distributions in the gel were compared to treatment planning system for benchmark irradiations and quality of agreement is assessed using clinically relevant gamma index criteria. Results: The dosimetric response of the gel was mapped up to 600 cGy using an electron-based calibration technique. Excellent dosimetric agreement is observed between ion chamber data and gel. The most notable result of this work is the fact that this gel has no observed dose quenching in the Bragg peak region. Quantitative dose distribution comparisons to treatment planning system calculations show that most (>97%) of the gel dose maps pass the 3%/3 mm gamma criterion. Conclusions: This study shows that the new proton-sensitive gel dosimeter is capable of reproducing ion chamber dose data for modulated and nonmodulated Bragg peak beams with different clinical beam energies. The findings suggest that the gel dosimeter can be used as QA tool for millimeter range verification of proton beam deliveries in the dosimeter medium.

Impacts of aerosol mitigation on Chinese rice photosynthesis: An integrated modeling approach

Science.gov (United States)

Zhang, T.; Li, T.; Yue, X.; Yang, X.

2017-12-01

Aerosol pollution in China is significantly altering radiative transfer processes and is thereby potentially affecting rice photosynthesis. However, the response of rice photosynthesis to aerosol-induced radiative perturbations is still not well understood. Here, we employ an integrated process-based modeling approach to simulate changes in incoming radiation (RAD) and the diffuse radiation fraction (DF) with aerosol mitigation in China and their associated impacts on rice yields. Aerosol reduction has the positive effect of increasing RAD and the negative effect of decreasing DF on rice photosynthesis and yields. In rice production areas where the average RAD during the growing season is lower than 250 W m-2, aerosol reduction is beneficial for higher rice yields, whereas in areas with RAD>250 W m-2, aerosol mitigation causes yield declines due to the associated reduction in the DF, which decreases the light use efficiency. This response pattern and threshold are similar with observations, even through more data are needed in future investigation. As a net effect, rice yields were estimated to significantly increase by 0.8-2.6% with aerosol concentrations reductions from 20 to 100%, which is lower than the estimates obtained in earlier studies that only considered the effects of RAD. This finding suggests that both RAD and DF are important processes influencing rice yields and should be incorporated into future assessments of agricultural responses to variations in aerosol-induced radiation under climate change.

Anti-inflammatory activity of Achillea and Ruscus topical gel on carrageenan-induced paw edema in rats.

Science.gov (United States)

Maswadeh, Hamzah M; Semreen, Mohammad H; Naddaf, Ahmad R

2006-01-01

The anti-inflammatory activity of Achillea and Ruscus extracts was studied in comparison with diclofenac sodium topical gel (diclosal Emulgel), using the carrageenan induced paw edema model in Albino rats. Gel formulation was prepared containing 6% of each extract in gel base, namely sodium carboxymethylcellulose (NaCMC). The kinetics of drug release from the prepared formulation was studied separately in each case. Results showed that the release follows the Higuchi square root equation. The pharmacological screening revealed that the percent reduction of edema for Achillea extract and Ruscus extract were 48.1% and 18.8%, respectively, while diclosal Emulgel produced 47% reduction of edema.

The nature and principles of the radiation-induced cancerogenesis

International Nuclear Information System (INIS)

Lips'ka, A.YI.; Serkyiz, Ya.Yi.

2004-01-01

The paper represents the analysis of the authors and literary data concerning the nature and principles of the radiation-induced neoplasms. The mechanisms of the radiation-induced cancerogenesis development are not clear understood. The experimental data altogether do not allow developing the mathematical model of the radiation-induced cancerogenesis at the molecular level. This model has to take into account all necessary indices including radiation factor and the state of the organism. The general principles of the radiation-induced cancerogenesis have been formulated in the present review. It is possible to use these principles in order to predict and calculate the risks of the radiation-induced neoplasms

Minimalist fault-tolerance techniques for mitigating single-event effects in non-radiation-hardened microcontrollers

Science.gov (United States)

Caldwell, Douglas Wyche

Commercial microcontrollers--monolithic integrated circuits containing microprocessor, memory and various peripheral functions--such as are used in industrial, automotive and military applications, present spacecraft avionics system designers an appealing mix of higher performance and lower power together with faster system-development time and lower unit costs. However, these parts are not radiation-hardened for application in the space environment and Single-Event Effects (SEE) caused by high-energy, ionizing radiation present a significant challenge. Mitigating these effects with techniques which require minimal additional support logic, and thereby preserve the high functional density of these devices, can allow their benefits to be realized. This dissertation uses fault-tolerance to mitigate the transient errors and occasional latchups that non-hardened microcontrollers can experience in the space radiation environment. Space systems requirements and the historical use of fault-tolerant computers in spacecraft provide context. Space radiation and its effects in semiconductors define the fault environment. A reference architecture is presented which uses two or three microcontrollers with a combination of hardware and software voting techniques to mitigate SEE. A prototypical spacecraft function (an inertial measurement unit) is used to illustrate the techniques and to explore how real application requirements impact the fault-tolerance approach. Low-cost approaches which leverage features of existing commercial microcontrollers are analyzed. A high-speed serial bus is used for voting among redundant devices and a novel wire-OR output voting scheme exploits the bidirectional controls of I/O pins. A hardware testbed and prototype software were constructed to evaluate two- and three-processor configurations. Simulated Single-Event Upsets (SEUs) were injected at high rates and the response of the system monitored. The resulting statistics were used to evaluate

Attenuation of adjuvant-induced arthritis in rats by phonophoresis with an aqueous gel of the Amazonian plant Elaeoluma nuda (Sapotaceae).

Science.gov (United States)

Merini, Lilian Regiani; Furtado, Silvânia da Conceição; de Oliveira, Marcelo Miguel Brito; Carneiro, Ana Lúcia Basílio; Boechat, Antonio Luiz; Barcellos, José Fernando Marques

2014-02-01

Various species of the genus Pouteria (Elaeoluma) are used by the native population of Brazil because of, among other factors, their anti-inflammatory properties. The anti-inflammatory properties of the extract of the Amazonian plant Elaeoluma nuda were recently identified in prospective pharmacological studies. The objective of this study was to assess the anti-inflammatory effect of phonophoresis with aqueous gel extract of E. nuda in rat adjuvant-induced arthritis. Arthritis was induced in Lewis rats with an adjuvant. Phonophoresis with E. nuda gel was then administered daily and the results compared with those obtained with phonophoresis of diclofenac diethylammonium gel and ultrasound therapy without phonophoresis. Arthritis in the different groups was evaluated by plethysmometry. Proinflammatory cytokines TNF-α and IL-1α were quantified by cytometric bead array (CBA). The effect of phonophoresis of aqueous gel with E. nuda extract on arthritis in rats' paws (a 33% reduction compared with the controls) was the same as that produced by phonophoresis with diclofenac diethylammonium. Ultrasound therapy without phonophoresis produced no significant effect on the 21st day of therapy. There was a significant reduction in TNF-α and IL-1α levels in the group treated with phonophoresis with E. nuda gel (p=0.0042; p=0.0003, respectively). Our results demonstrate the anti-inflammatory effect of phonophoresis with E. nuda gel on cytokines TNF-α, IL-1α and adjuvant-induced arthritis. Copyright © 2013 Elsevier Ltd. All rights reserved.

Radiation Mitigation and Power Optimization Design Tools for Reconfigurable Hardware in Orbit

Science.gov (United States)

French, Matthew; Graham, Paul; Wirthlin, Michael; Wang, Li; Larchev, Gregory

2005-01-01

The Reconfigurable Hardware in Orbit (RHinO)project is focused on creating a set of design tools that facilitate and automate design techniques for reconfigurable computing in space, using SRAM-based field-programmable-gate-array (FPGA) technology. In the second year of the project, design tools that leverage an established FPGA design environment have been created to visualize and analyze an FPGA circuit for radiation weaknesses and power inefficiencies. For radiation, a single event Upset (SEU) emulator, persistence analysis tool, and a half-latch removal tool for Xilinx/Virtex-II devices have been created. Research is underway on a persistence mitigation tool and multiple bit upsets (MBU) studies. For power, synthesis level dynamic power visualization and analysis tools have been completed. Power optimization tools are under development and preliminary test results are positive.

Single-strand breaks in oligodeoxyribonucleotides induced by fission neutrons and gamma radiation and measured by gel electrophoresis. Protective effects of aminothiols

International Nuclear Information System (INIS)

Swenberg, C.E.; Vaishnav, Y.N.; Li, Bin; Tsao, Hong; Mao, Bing; Geacintov, N.E.

1997-01-01

The technique of high-resolution gel electrophoresis using oligodeoxyribonucleotides of known composition as model systems, offers a simple quantitative estimate of DNA damage in aqueous solution induced by ionizing radiation. The fraction of damaged DNA can be quantitatively defined in terms of the increased electrophoretic mobilities of the damaged oligonucleotides, relative to the mobility of the unirradiated and intact oligonucleotides. The usual direct strand breaks can be observed at γ-ray dosages of 200 Gy. However, at a γ-ray dosage of 400 Gy, only a broad background, attributed to heterogeneously and multiply damaged oligonucleotide fragments with overlapping and varying electrophoretic mobilities, can be distinguished. On the other hand, individual bands due to resolvable DNA fragments are evident even at dosages as high as 400 Gy for fission neutrons. When double-stranded oligonucleotides are exposed to γ-ray dosages of 200 Gy, the fraction of damaged DNA approaches 30-40%. This damage can be almost completely suppressed (>99%) if the irradiations are conducted in aqueous solutions in the presence of 0.5-1.0 mM concentrations of the thiols cysteamine or 3-(3-methylaminopropylamino)propanethiol (WR-151326). The rate constant of reaction of OH·radicals with small double stranded oligonucleotides 16 base pairs long, K DNA , is found to be closer to the diffusion-controlled value (>3 x 10 9 M -1 s -1 ) than the magnitudes of K DNA for the higher molecular weight, native DNA reported in the literature. These observations suggest that oligonucleotides represent more simple model systems than native DNA in solutions for studying the mechanisms of radioprotection exerted by thiols of different structures. (author)

Solving radiation problems at particle accelerators

Energy Technology Data Exchange (ETDEWEB)

Nikolai V. Mokhov

2001-12-11

At high-intensity high-energy particle accelerators, consequences of a beam-induced radiation impact on machine and detector components, people, environment and complex performance can range from negligible to severe. The specifics, general approach and tools used at such machines for radiation analysis are described. In particular, the world leader Fermilab accelerator complex is considered, with its fixed target and collider experiments, as well as new challenging projects such as LHC, VLHC, muon collider and neutrino factory. The emphasis is on mitigation of deleterious beam-induced radiation effects and on the key role of effective computer simulations.

Solving radiation problems at particle accelerators

International Nuclear Information System (INIS)

Mokhov, N.V.

2001-01-01

At high-intensity high-energy particle accelerators, consequences of a beam-induced radiation impact on machine and detector components, people, environment and complex performance can range from negligible to severe. The specifics, general approach and tools used at such machines for radiation analysis are described. In particular, the world leader Fermilab accelerator complex is considered, with its fixed target and collider experiments, as well as new challenging projects such as LHC, VLHC, muon collider and neutrino factory. The emphasis is on mitigation of deleterious beam-induced radiation effects and on the key role of effective computer simulations

Radiation-induced linking reactions in polyethylene

International Nuclear Information System (INIS)

Zoepfl, F.J.

1983-01-01

Three types of measurements are reported relating to chemical reactions in polyethylene induced by ionizing radiation: 1) viscometric and low-angle laser light scattering measurements to determine the effect of a radical scavenger on the yield of links; 2) calorimetric measurements to determine the effect of radiation-induced linking on the melting behavior of polyethylene; and 3) high-resolution solution carbon 13 nuclear magnetic resonance (NMR) spectrometry measurements to determine the nature of the links and the method of their formation. The NMR results present the first direct detection of radiation-induced long-chain branching (Y links) in polyethylene, and place an apparent upper limit on the yield of H-shaped crosslinks that are formed when polyethylene is irradiated to low absorbed doses. The effect of radiation-induced linking on the melting behavior of polyethylene was examined using differential scanning calorimetry (DSC). It was found that radiation-induced links do not change the heat of fusion of polythylene crystals, but decrease the melt entropy and increase the fold surface free energy per unit area of the crystals. The carbon 13 NMR results demonstrate that long-chain branches (Y links) are formed much more frequently than H-shaped crosslinks at low absorbed doses. The Y links are produced by reactions of alkyl free radicals with terminal vinyl groups in polyethylene

Genetic alterations during radiation-induced carcinogenesis

International Nuclear Information System (INIS)

Kodama, Seiji

1995-01-01

This paper reviews radiation-induced genetic alterations and its carcinogenesis, focusing on the previous in vitro assay outcome. A colony formation assay using Syrian hamster fetal cells and focus formation assay using mouse C3H10T1/2 cells are currently available to find malignant transformation of cells. Such in vitro assays has proposed the hypothesis that radiation-induced carcinogenesis arises from at least two-stage processes; i.e., that an early step induced by irradiation plays an important role in promoting the potential to cause the subsequent mutation. A type of genetic instability induced by radiation results in a persistently elevated frequency of spontaneous mutations, so-called the phenomenon of delayed reproductive death. One possible mechanism by which genetic instability arises has been shown to be due to the development of abnormality in the gene group involved in the maintenance mechanism of genome stability. Another possibility has also been shown to stem from the loss of telomere (the extremities of a chromosome). The importance of search for radiation-induced genetic instability is emphasized in view of the elucidation of carcinogenesis. (N.K.)

Evaluation of radiation-induced genotoxicity on human melanoma cells (SK-MEL-37) by flow cytometry

International Nuclear Information System (INIS)

Bonfim, Leticia; Carvalho, Luma Ramirez de; Vieira, Daniel Perez

2017-01-01

Micronucleus assay is a test used to evaluate genotoxic damage in cells, which can be caused by various factors, like ionizing radiation. Interactions between radiation energies and DNA can cause breakage, leading to use chromosomal mutations or loss of genetic material, important events that could be induced in solid tumors to mitigate its expansion within human body. Melanoma has been described as a tumor with increased radio resistance. This work evaluated micronuclei percentages (%MN) in human melanoma cells (SK-MEL-37), irradiated by gamma radiation, with doses between 0 and 16Gy. Cell suspensions were irradiated in PBS by a "6"0Co source in doses between 0 and 16Gy, and incubated by 48h. Then cell membranes were lysed in the presence of SYTOX Green and EMA dyes, preserving nuclear membranes. Using this method, EMA-stained nuclei could be discriminated as those derived from dead cells, and SYTOX nuclei and micronuclei could be quantified. Micronuclei percentages were found to be proportional to dose, (R2 = 0.997). Only the highest dose (16Gy) could induce statistically significant increase of MN (p<0.0001), although cultures irradiated by 4, 8 and 16Gy showed significant increase of dead cell fractions. Calculation of the nuclei-to-beads ratio showed that 8 and 16Gy could reduce melanoma cell proliferation. Results showed that although cell death and loss of proliferative capacity could be observed on cultures irradiated at lower doses, genotoxic damage could be induced only on a higher dose. Resistance to radiation-induced genotoxicity could explain a relatively high radio resistance of melanoma tumors. (author)

Evaluation of radiation-induced genotoxicity on human melanoma cells (SK-MEL-37) by flow cytometry

Energy Technology Data Exchange (ETDEWEB)

Bonfim, Leticia; Carvalho, Luma Ramirez de; Vieira, Daniel Perez, E-mail: leticia.bonfim@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2017-11-01

Micronucleus assay is a test used to evaluate genotoxic damage in cells, which can be caused by various factors, like ionizing radiation. Interactions between radiation energies and DNA can cause breakage, leading to use chromosomal mutations or loss of genetic material, important events that could be induced in solid tumors to mitigate its expansion within human body. Melanoma has been described as a tumor with increased radio resistance. This work evaluated micronuclei percentages (%MN) in human melanoma cells (SK-MEL-37), irradiated by gamma radiation, with doses between 0 and 16Gy. Cell suspensions were irradiated in PBS by a {sup 60}Co source in doses between 0 and 16Gy, and incubated by 48h. Then cell membranes were lysed in the presence of SYTOX Green and EMA dyes, preserving nuclear membranes. Using this method, EMA-stained nuclei could be discriminated as those derived from dead cells, and SYTOX nuclei and micronuclei could be quantified. Micronuclei percentages were found to be proportional to dose, (R2 = 0.997). Only the highest dose (16Gy) could induce statistically significant increase of MN (p<0.0001), although cultures irradiated by 4, 8 and 16Gy showed significant increase of dead cell fractions. Calculation of the nuclei-to-beads ratio showed that 8 and 16Gy could reduce melanoma cell proliferation. Results showed that although cell death and loss of proliferative capacity could be observed on cultures irradiated at lower doses, genotoxic damage could be induced only on a higher dose. Resistance to radiation-induced genotoxicity could explain a relatively high radio resistance of melanoma tumors. (author)

Cation-induced folding of alginate-bearing bilayer gels: an unusual example of spontaneous folding along the long axis.

Science.gov (United States)

Athas, Jasmin C; Nguyen, Catherine P; Kummar, Shailaa; Raghavan, Srinivasa R

2018-04-04

The spontaneous folding of flat gel films into tubes is an interesting example of self-assembly. Typically, a rectangular film folds along its short axis when forming a tube; folding along the long axis has been seen only in rare instances when the film is constrained. Here, we report a case where the same free-swelling gel film folds along either its long or short axis depending on the concentration of a solute. Our gels are sandwiches (bilayers) of two layers: a passive layer of cross-linked N,N'-dimethylyacrylamide (DMAA) and an active layer of cross-linked DMAA that also contains chains of the biopolymer alginate. Multivalent cations like Ca2+ and Cu2+ induce these bilayer gels to fold into tubes. The folding occurs instantly when a flat film of the gel is introduced into a solution of these cations. The likely cause for folding is that the active layer stiffens and shrinks (because the alginate chains in it get cross-linked by the cations) whereas the passive layer is unaffected. The resulting mismatch in swelling degree between the two layers creates internal stresses that drive folding. Cations that are incapable of cross-linking alginate, such as Na+ and Mg2+, do not induce gel folding. Moreover, the striking aspect is the direction of folding. When the Ca2+ concentration is high (100 mM or higher), the gels fold along their long axis, whereas when the Ca2+ concentration is low (40 to 80 mM), the gels fold along their short axis. We hypothesize that the folding axis is dictated by the inhomogeneous nature of alginate-cation cross-linking, i.e., that the edges get cross-linked before the faces of the gel. At high Ca2+ concentration, the stiffer edges constrain the folding; in turn, the gel folds such that the longer edges are deformed less, which explains the folding along the long axis. At low Ca2+ concentration, the edges and the faces of the gel are more similar in their degree of cross-linking; therefore, the gel folds along its short axis. An analogy

An intelligent biopolymer gel with pendant L-proline methyl ester

International Nuclear Information System (INIS)

Yoshida, Masaru; Safranj, A.; Omichi, Hideki; Katakai, Ryoichi.

1995-01-01

Linear poly(acryloyl-L-proline methyl ester, A-ProOMe), obtained by radiation-induced polymerization of its monomer in ethanol, exhibits a lower critical solution temperature (LCST) at 14degC. A-ProOMe was copolymerized with a minor amount of 2-hydroxypropyl methacrylate (HPMA) or 2-hydroxyethyl methacrylate (HEMA), to obtain intelligent biopolymer gels for application in drug delivery systems. The poly(A-ProOMe/HPMA) gel was characterized by an initial rapid shrinkage at the surface in the swollen state, as resulting in formation of a rigid membrane barrier devoid of micropores. This gel is called a surface regulated matrix. In the case of poly(A-ProOMe/HEMA), no such a barrier formed, instead, the whole matrix shrunk without the disappearance of micropores. This gel is called a matrix pumping gel. Testosterone (T) was incorporated into the poly(A-ProOMe/HPMA) gel, and it was found that the daily dose of T released in vivo from this formulation remained constant at approximately 30 μg/day throughout an experimental period of 54 weeks. On the other hand, 9-β-D-arabinofuranosyladenine (Ara-A) was incorporated into the poly(A-ProOMe/HEMA) gel to evaluate the pulsatile drug release when cycled at 10 and 37degC. The in vitro release rate of Ara-A was found to be 11 ng/h at 10degC and 33 ng/h at 37degC. (author)

The Effect of Gel Microstructure on Simulated Gastric Digestion of Protein Gels

NARCIS (Netherlands)

Opazo-Navarrete, Mauricio; Altenburg, Marte D.; Boom, Remko M.; Janssen, Anja E.M.

2018-01-01

The objective of this study was to analyse the impact of the gel structure obtained by different heat-induced temperatures on the in vitro gastric digestibility at pH 2. To achieve this, gels were prepared from soy protein, pea protein, albumin from chicken egg white and whey protein isolate at

Effect of the crystallinity in the Tl signal induced by the gamma radiation in Al{sub 2}O{sub 3}: Eu obtained by the sol gel method; Efecto de la cristalinidad en la senal Tl inducida por la radiacion gamma en Al{sub 2}O{sub 3}: Eu obtenida por el metodo sol gel

Energy Technology Data Exchange (ETDEWEB)

Mendoza A, D.; Gonzalez M, P.R. [ININ, Gerencia de Ciencias de Materiales. Carr. Mexico-Toluca Km. 36.5, 52045 Ocoyoacac (Mexico); Custodio, E. [Universidad Juarez Autonoma de Tabasco, DACB, Carr. Cunduacan-Jalpa, km. 1.5, 86680 Tabasco (Mexico); Rubio, E.; Rodriguez L, V. [Facultad de Ingenieria Quimica, BUAP. Av. San Claudio y 18 Sur Col. San Manuel. C. P. 72570.C.U. Puebla (Mexico)

2004-07-01

In this work the synthesis and characterization process of Al{sub 2}O{sub 3} and Al{sub 2}O{sub 3}: Eu by sol gel method is reported. A previous thermal treatment at 500 and 1000 C on the material powder type showed a notable influences on the thermoluminescent signal induced by the gamma radiation, such that the intensity thermoluminescent signal produced by samples with thermal treatment at 1000 C is much bigger that thermoluminescent signal produced by samples thermal treatment at 500 C. In order to explain this behavior, an analysis for X-ray diffraction and electron microscopy was also realized. The results show a notably influence of the crystalline array and the microstructure on the thermoluminescent behavior of the alumina. (Author)

Cyclic compression maintains viability and induces chondrogenesis of human mesenchymal stem cells in fibrin gel scaffolds.

Science.gov (United States)

Pelaez, Daniel; Huang, Chun-Yuh Charles; Cheung, Herman S

2009-01-01

Mechanical loading has long been shown to modulate cartilage-specific extracellular matrix synthesis. With joint motion, cartilage can experience mechanical loading in the form of compressive, tensile or shearing load, and hydrostatic pressure. Recent studies have demonstrated the capacity of unconfined cyclic compression to induce chondrogenic differentiation of human mesenchymal stem cell (hMSC) in agarose culture. However, the use of a nonbiodegradable material such as agarose limits the applicability of these constructs. Of the possible biocompatible materials available for tissue engineering, fibrin is a natural regenerative scaffold, which possesses several desired characteristics including a controllable degradation rate and low immunogenicity. The objective of the present study was to determine the capability of fibrin gels for supporting chondrogenesis of hMSCs under cyclic compression. To optimize the system, three concentrations of fibrin gel (40, 60, and 80 mg/mL) and three different stimulus frequencies (0.1, 0.5, and 1.0 Hz) were used to examine the effects of cyclic compression on viability, proliferation and chondrogenic differentiation of hMSCs. Our results show that cyclic compression (10% strain) at frequencies >0.5 Hz and gel concentration of 40 mg/mL fibrinogen appears to maintain cellular viability within scaffolds. Similarly, variations in gel component concentration and stimulus frequency can be modified such that a significant chondrogenic response can be achieved by hMSC in fibrin constructs after 8 h of compression spread out over 2 days. This study demonstrates the suitability of fibrin gel for supporting the cyclic compression-induced chondrogenesis of mesenchymal stem cells.

Radiation-induced brain injury: A review

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Greene-Schloesser, Dana; Robbins, Mike E.; Peiffer, Ann M.; Shaw, Edward G. [Department of Radiation Oncology, Wake Forest School of Medicine,, Winston-Salem, NC (United States); Brain Tumor Center of Excellence, Wake Forest School of Medicine,, Winston-Salem, NC (United States); Wheeler, Kenneth T. [Brain Tumor Center of Excellence, Wake Forest School of Medicine,, Winston-Salem, NC (United States); Department of Radiology, Wake Forest School of Medicine,, Winston-Salem, NC (United States); Chan, Michael D., E-mail: mrobbins@wakehealth.edu [Department of Radiation Oncology, Wake Forest School of Medicine,, Winston-Salem, NC (United States); Brain Tumor Center of Excellence, Wake Forest School of Medicine,, Winston-Salem, NC (United States)

2012-07-19

Approximately 100,000 primary and metastatic brain tumor patients/year in the US survive long enough (>6 months) to experience radiation-induced brain injury. Prior to 1970, the human brain was thought to be highly radioresistant; the acute CNS syndrome occurs after single doses >30 Gy; white matter necrosis occurs at fractionated doses >60 Gy. Although white matter necrosis is uncommon with modern techniques, functional deficits, including progressive impairments in memory, attention, and executive function have become important, because they have profound effects on quality of life. Preclinical studies have provided valuable insights into the pathogenesis of radiation-induced cognitive impairment. Given its central role in memory and neurogenesis, the majority of these studies have focused on the hippocampus. Irradiating pediatric and young adult rodent brains leads to several hippocampal changes including neuroinflammation and a marked reduction in neurogenesis. These data have been interpreted to suggest that shielding the hippocampus will prevent clinical radiation-induced cognitive impairment. However, this interpretation may be overly simplistic. Studies using older rodents, that more closely match the adult human brain tumor population, indicate that, unlike pediatric and young adult rats, older rats fail to show a radiation-induced decrease in neurogenesis or a loss of mature neurons. Nevertheless, older rats still exhibit cognitive impairment. This occurs in the absence of demyelination and/or white matter necrosis similar to what is observed clinically, suggesting that more subtle molecular, cellular and/or microanatomic modifications are involved in this radiation-induced brain injury. Given that radiation-induced cognitive impairment likely reflects damage to both hippocampal- and non-hippocampal-dependent domains, there is a critical need to investigate the microanatomic and functional effects of radiation in various brain regions as well as their

Radiation-induced brain injury: A review

International Nuclear Information System (INIS)

Greene-Schloesser, Dana; Robbins, Mike E.; Peiffer, Ann M.; Shaw, Edward G.; Wheeler, Kenneth T.; Chan, Michael D.

2012-01-01

Approximately 100,000 primary and metastatic brain tumor patients/year in the US survive long enough (>6 months) to experience radiation-induced brain injury. Prior to 1970, the human brain was thought to be highly radioresistant; the acute CNS syndrome occurs after single doses >30 Gy; white matter necrosis occurs at fractionated doses >60 Gy. Although white matter necrosis is uncommon with modern techniques, functional deficits, including progressive impairments in memory, attention, and executive function have become important, because they have profound effects on quality of life. Preclinical studies have provided valuable insights into the pathogenesis of radiation-induced cognitive impairment. Given its central role in memory and neurogenesis, the majority of these studies have focused on the hippocampus. Irradiating pediatric and young adult rodent brains leads to several hippocampal changes including neuroinflammation and a marked reduction in neurogenesis. These data have been interpreted to suggest that shielding the hippocampus will prevent clinical radiation-induced cognitive impairment. However, this interpretation may be overly simplistic. Studies using older rodents, that more closely match the adult human brain tumor population, indicate that, unlike pediatric and young adult rats, older rats fail to show a radiation-induced decrease in neurogenesis or a loss of mature neurons. Nevertheless, older rats still exhibit cognitive impairment. This occurs in the absence of demyelination and/or white matter necrosis similar to what is observed clinically, suggesting that more subtle molecular, cellular and/or microanatomic modifications are involved in this radiation-induced brain injury. Given that radiation-induced cognitive impairment likely reflects damage to both hippocampal- and non-hippocampal-dependent domains, there is a critical need to investigate the microanatomic and functional effects of radiation in various brain regions as well as their

Laser CT evaluation on normoxic PAGAT gel dosimeter

International Nuclear Information System (INIS)

Kumar, D S; Samuel, E J J; Watanabe, Y

2013-01-01

Optical computed tomography has been shown to be a potentially useful imaging tool for the radiation therapy physicists. In radiation therapy, researchers have used optical CT for the readout of 3D dosimeters. The purpose of this paper is to describe the initial evaluation of a newly fabricated laser CT scanner for 3D gel dosimetry which works using the first generation principle. A normoxic PAGAT (Polyacrylamide Gelatin and Tetrakis) gel is used as a dosimeter for this analysis. When a laser passes through the gel phantom, absorption and scattering of photon take place. The optical attenuation coefficient of the laser can be obtained by measuring its intensity after passing through the gel by a sensor. The scanner motion is controlled by a computer program written in Microsoft Visual C++. Reconstruction and data analysis on the irradiated gel phantom is performed by suitable algorithm using Matlab software.

Optical CT evaluation on normoxic polymer gel dosimeter

International Nuclear Information System (INIS)

Samuel, E. James Jebaseelan

2013-01-01

Optical computed tomography has been shown to be a potentially useful imaging tool for the radiation therapy physicists. In radiation therapy, researchers have used optical CT for the readout of 3D dosimeters. The purpose of this paper is to explicate the initial evaluation of a newly fabricated laser CT scanner for '3D gel dosimetry' which works in the first generation principle. The normoxic PAGAT (Polyacrylamide Gelatin and Tetrakis) gel is used as a dosimeter for this analysis. When laser passes through this gel phantom, absorption and scattering of photon take place. The optical attenuation coefficient of the laser can be obtained by measuring its intensity after passing through the gel by a sensor.The scanner motion is controlled by the program written in Microsoft Visual C++. Reconstruction and data analysis on the irradiated gel phantom is performed by suitable algorithm using Matlab software. (author)

Delayed Radiation-Induced Vasculitic Leukoencephalopathy

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Rauch, Philipp J. [Departments of Pathology and Neurosurgery, Yale University School of Medicine, New Haven, Connecticut (United States); Faculty of Medicine, University of Heidelberg, Heidelberg (Germany); Park, Henry S. [Departments of Pathology and Neurosurgery, Yale University School of Medicine, New Haven, Connecticut (United States); Knisely, Jonathan P.S. [Department of Radiation Medicine, North Shore University Hospital, Manhasset, New York (United States); Chiang, Veronica L. [Departments of Pathology and Neurosurgery, Yale University School of Medicine, New Haven, Connecticut (United States); Vortmeyer, Alexander O., E-mail: alexander.vortmeyer@yale.edu [Departments of Pathology and Neurosurgery, Yale University School of Medicine, New Haven, Connecticut (United States)

2012-05-01

Purpose: Recently, single-fraction, high-dosed focused radiation therapy such as that administered by Gamma Knife radiosurgery has been used increasingly for the treatment of metastatic brain cancer. Radiation therapy to the brain can cause delayed leukoencephalopathy, which carries its own significant morbidity and mortality. While radiosurgery-induced leukoencephalopathy is known to be clinically different from that following fractionated radiation, pathological differences are not well characterized. In this study, we aimed to integrate novel radiographic and histopathologic observations to gain a conceptual understanding of radiosurgery-induced leukoencephalopathy. Methods and Materials: We examined resected tissues of 10 patients treated at Yale New Haven Hospital between January 1, 2009, and June 30, 2010, for brain metastases that had been previously treated with Gamma Knife radiosurgery, who subsequently required surgical management of a symptomatic regrowing lesion. None of the patients showed pathological evidence of tumor recurrence. Clinical and magnetic resonance imaging data for each of the 10 patients were then studied retrospectively. Results: We provide evidence to show that radiosurgery-induced leukoencephalopathy may present as an advancing process that extends beyond the original high-dose radiation field. Neuropathologic examination of the resected tissue revealed traditionally known leukoencephalopathic changes including demyelination, coagulation necrosis, and vascular sclerosis. Unexpectedly, small and medium-sized vessels revealed transmural T-cell infiltration indicative of active vasculitis. Conclusions: We propose that the presence of a vasculitic component in association with radiation-induced leukoencephalopathy may facilitate the progressive nature of the condition. It may also explain the resemblance of delayed leukoencephalopathy with recurring tumor on virtually all imaging modalities used for posttreatment follow-up.

Evaluation of polymer gels and MRI as a 3-D dosimeter for intensity-modulated radiation therapy.

Science.gov (United States)

Low, D A; Dempsey, J F; Venkatesan, R; Mutic, S; Markman, J; Mark Haacke, E; Purdy, J A

1999-08-01

BANG gel (MGS Research, Inc., Guilford, CT) has been evaluated for measuring intensity-modulated radiation therapy (IMRT) dose distributions. Treatment plans with target doses of 1500 cGy were generated by the Peacock IMRT system (NOMOS Corp., Sewickley, PA) using test target volumes. The gels were enclosed in 13 cm outer diameter cylindrical glass vessels. Dose calibration was conducted using seven smaller (4 cm diameter) cylindrical glass vessels irradiated to 0-1800 cGy in 300 cGy increments. Three-dimensional maps of the proton relaxation rate R2 were obtained using a 1.5 T magnetic resonance imaging (MRI) system (Siemens Medical Systems, Erlangen, Germany) and correlated with dose. A Hahn spin echo sequence was used with TR = 3 s, TE = 20 and 100 ms, NEX = 1, using 1 x 1 x 3 mm3 voxels. The MRI measurements were repeated weekly to identify the gel-aging characteristics. Ionization chamber, thermoluminescent dosimetry (TLD), and film dosimetry measurements of the IMRT dose distributions were obtained to compare against the gel results. The other dosimeters were used in a phantom with the same external cross-section as the gel phantom. The irradiated R2 values of the large vessels did not precisely track the smaller vessels, so the ionization chamber measurements were used to normalize the gel dose distributions. The point-to-point standard deviation of the gel dose measurements was 7.0 cGy. When compared with the ionization chamber measurements averaged over the chamber volume, 1% agreement was obtained. Comparisons against radiographic film dose distribution measurements and the treatment planning dose distribution calculation were used to determine the spatial localization accuracy of the gel and MRI. Spatial localization was better than 2 mm, and the dose was accurately determined by the gel both within and outside the target. The TLD chips were placed throughout the phantom to determine gel measurement precision in high- and low-dose regions. A

Computer modelling of radiation-induced bystander effect

International Nuclear Information System (INIS)

Khvostunov, Igor K.; Nikjoo, Hooshang

2002-01-01

Radiation-induced genomic instability and bystander effects are now well established consequences of exposure of living cells to ionising radiation. It has been observed that cells not directly hit by radiation tracks may still exhibit radiation effects. We present a quantitative modelling of the radiation-induced bystander effect based on a diffusion model of spreading the bystander signal. The model assumes the bystander factor to be a protein of low molecular weight, given out by the hit cell, diffusing in the medium and reacting with non-hit cells. The model calculations successfully predict the results of cell survival in an irradiated conditioned medium. The model predicts the shape of dose-effect relationship for cell survival and oncogenic transformation induced by broad-beam and micro-beam irradiation by alpha-particles. (author)

Simvastatin mitigates increases in risk factors for and the occurrence of cardiac disease following 10 Gy total body irradiation.

Science.gov (United States)

Lenarczyk, Marek; Su, Jidong; Haworth, Steven T; Komorowski, Richard; Fish, Brian L; Migrino, Raymond Q; Harmann, Leanne; Hopewell, John W; Kronenberg, Amy; Patel, Shailendra; Moulder, John E; Baker, John E

2015-06-01

The ability of simvastatin to mitigate the increases in risk factors for and the occurrence of cardiac disease after 10 Gy total body irradiation (TBI) was determined. This radiation dose is relevant to conditioning for stem cell transplantation and threats from radiological terrorism. Male rats received single dose TBI of 10 Gy. Age-matched, sham-irradiated rats served as controls. Lipid profile, heart and liver morphology and cardiac mechanical function were determined for up to 120 days after irradiation. TBI resulted in a sustained increase in total- and LDL-cholesterol (low-density lipoprotein-cholesterol), and triglycerides. Simvastatin (10 mg/kg body weight/day) administered continuously from 9 days after irradiation mitigated TBI-induced increases in total- and LDL-cholesterol and triglycerides, as well as liver injury. TBI resulted in cellular peri-arterial fibrosis, whereas control hearts had less collagen and fibrosis. Simvastatin mitigated these morphological injuries. TBI resulted in cardiac mechanical dysfunction. Simvastatin mitigated cardiac mechanical dysfunction 20-120 days following TBI. To determine whether simvastatin affects the ability of the heart to withstand stress after TBI, injury from myocardial ischemia/reperfusion was determined in vitro. TBI increased the severity of an induced myocardial infarction at 20 and 80 days after irradiation. Simvastatin mitigated the severity of this myocardial infarction at 20 and 80 days following TBI. It is concluded simvastatin mitigated the increases in risk factors for cardiac disease and the extent of cardiac disease following TBI. This statin may be developed as a medical countermeasure for the mitigation of radiation-induced cardiac disease.

4-phenylbutyrate Mitigates Fluoride-Induced Cytotoxicity in ALC Cells

Directory of Open Access Journals (Sweden)

Maiko Suzuki

2017-05-01

Full Text Available Chronic fluoride over-exposure during pre-eruptive enamel development can cause dental fluorosis. Severe dental fluorosis is characterized by porous, soft enamel that is vulnerable to erosion and decay. The prevalence of dental fluorosis among the population in the USA, India and China is increasing. Other than avoiding excessive intake, treatments to prevent dental fluorosis remain unknown. We previously reported that high-dose fluoride induces endoplasmic reticulum (ER stress and oxidative stress in ameloblasts. Cell stress induces gene repression, mitochondrial damage and apoptosis. An aromatic fatty acid, 4-phenylbutyrate (4PBA is a chemical chaperone that interacts with misfolded proteins to prevent ER stress. We hypothesized that 4PBA ameliorates fluoride-induced ER stress in ameloblasts. To determine whether 4PBA protects ameloblasts from fluoride toxicity, we analyzed gene expression of Tgf-β1, Bcl2/Bax ratio and cytochrome-c release in vitro. In vivo, we measured fluorosis levels, enamel hardness and fluoride concentration. Fluoride treated Ameloblast-lineage cells (ALC had decreased Tgf-β1 expression and this was reversed by 4PBA treatment. The anti-apoptotic Blc2/Bax ratio was significantly increased in ALC cells treated with fluoride/4PBA compared to fluoride treatment alone. Fluoride treatment induced cytochrome-c release from mitochondria into the cytosol and this was inhibited by 4PBA treatment. These results suggest that 4PBA mitigates fluoride-induced gene suppression, apoptosis and mitochondrial damage in vitro. In vivo, C57BL/6J mice were provided fluoridated water for six weeks with either fluoride free control-chow or 4PBA-containing chow (7 g/kg 4PBA. With few exceptions, enamel microhardness, fluorosis levels, and fluoride concentrations of bone and urine did not differ significantly between fluoride treated animals fed with control-chow or 4PBA-chow. Although 4PBA mitigated high-dose fluoride toxicity in vitro, a diet

4-phenylbutyrate Mitigates Fluoride-Induced Cytotoxicity in ALC Cells.

Science.gov (United States)

Suzuki, Maiko; Everett, Eric T; Whitford, Gary M; Bartlett, John D

2017-01-01

Chronic fluoride over-exposure during pre-eruptive enamel development can cause dental fluorosis. Severe dental fluorosis is characterized by porous, soft enamel that is vulnerable to erosion and decay. The prevalence of dental fluorosis among the population in the USA, India and China is increasing. Other than avoiding excessive intake, treatments to prevent dental fluorosis remain unknown. We previously reported that high-dose fluoride induces endoplasmic reticulum (ER) stress and oxidative stress in ameloblasts. Cell stress induces gene repression, mitochondrial damage and apoptosis. An aromatic fatty acid, 4-phenylbutyrate (4PBA) is a chemical chaperone that interacts with misfolded proteins to prevent ER stress. We hypothesized that 4PBA ameliorates fluoride-induced ER stress in ameloblasts. To determine whether 4PBA protects ameloblasts from fluoride toxicity, we analyzed gene expression of Tgf -β 1, Bcl2 / Bax ratio and cytochrome-c release in vitro . In vivo , we measured fluorosis levels, enamel hardness and fluoride concentration. Fluoride treated Ameloblast-lineage cells (ALC) had decreased Tgf -β 1 expression and this was reversed by 4PBA treatment. The anti-apoptotic Blc2 / Bax ratio was significantly increased in ALC cells treated with fluoride/4PBA compared to fluoride treatment alone. Fluoride treatment induced cytochrome-c release from mitochondria into the cytosol and this was inhibited by 4PBA treatment. These results suggest that 4PBA mitigates fluoride-induced gene suppression, apoptosis and mitochondrial damage in vitro . In vivo , C57BL/6J mice were provided fluoridated water for six weeks with either fluoride free control-chow or 4PBA-containing chow (7 g/kg 4PBA). With few exceptions, enamel microhardness, fluorosis levels, and fluoride concentrations of bone and urine did not differ significantly between fluoride treated animals fed with control-chow or 4PBA-chow. Although 4PBA mitigated high-dose fluoride toxicity in vitro , a diet rich

Radiation-induced chromosomal instability

International Nuclear Information System (INIS)

Ritter, S.

1999-01-01

Recent studies on radiation-induced chromosomal instability in the progeny of exposed mammalian cells were briefly described as well as other related studies. For the analysis of chromosomal damage in clones, cells were seeded directly after exposure in cell well-dish to form single cell clones and post-irradiation chromosome aberrations were scored. Both exposure to isoeffective doses of X-ray or 270 MeV/u C-ions (13 keV/μm) increased the number of clones with abnormal karyotype and the increase was similar for X-ray and for C-ions. Meanwhile, in the progeny of cells for mass cultures, there was no indication of a delayed expression of chromosomal damage up to 40 population doublings after the exposure. A high number of aberrant cells were only observed directly after exposure to 10.7 MeV/u O-ions, i.e. in the first cycle cells and decreased with subsequent cell divisions. The reason for these differences in the radiation-induced chromosomal instability between clonal isolates and mass culture has not been clarified. Recent studies indicated that genomic instability occurs at a high frequency in the progeny of cells irradiated with both sparsely and densely ionizing radiation. Such genomic instability is thought likely to increase the risk of carcinogenesis, but more data are required for a well understanding of the health risks resulting from radiation-induced delayed instability. (M.N.)

A novel method of estimating dose responses for polymer gels using texture analysis of scanning electron microscopy images.

Directory of Open Access Journals (Sweden)

Cheng-Ting Shih

Full Text Available Polymer gels are regarded as a potential dosimeter for independent validation of absorbed doses in clinical radiotherapy. Several imaging modalities have been used to convert radiation-induced polymerization to absorbed doses from a macro-scale viewpoint. This study developed a novel dose conversion mechanism by texture analysis of scanning electron microscopy (SEM images. The modified N-isopropyl-acrylamide (NIPAM gels were prepared under normoxic conditions, and were administered radiation doses from 5 to 20 Gy. After freeze drying, the gel samples were sliced for SEM scanning with 50×, 500×, and 3500× magnifications. Four texture indices were calculated based on the gray level co-occurrence matrix (GLCM. The results showed that entropy and homogeneity were more suitable than contrast and energy as dose indices for higher linearity and sensitivity of the dose response curves. After parameter optimization, an R (2 value of 0.993 can be achieved for homogeneity using 500× magnified SEM images with 27 pixel offsets and no outlier exclusion. For dose verification, the percentage errors between the prescribed dose and the measured dose for 5, 10, 15, and 20 Gy were -7.60%, 5.80%, 2.53%, and -0.95%, respectively. We conclude that texture analysis can be applied to the SEM images of gel dosimeters to accurately convert micro-scale structural features to absorbed doses. The proposed method may extend the feasibility of applying gel dosimeters in the fields of diagnostic radiology and radiation protection.

Tracking of Nuclear Cable Insulation Polymer Structural Changes using the Gel Fraction and Uptake Factor Method

Energy Technology Data Exchange (ETDEWEB)

Correa, Miguel; Huang, Qian; Fifield, Leonard S.

2018-04-11

Cross-linked polyethylene (XLPE) cable insulation samples were exposed to heat and gamma radiation at a series of temperatures, dose rates, and exposure times to evaluate the effects of these variables on material degradation. The samples were tested using the solvent incubation method to collect gel fraction and uptake factor data in order to assess the crosslinking and chain scission occurring in polymer samples with aging. Consistent with previous reports, gel fraction values were observed to increase and uptake factor values to decrease with radiation and thermal exposure. The trends seen were also more prominent as exposure time increased, suggesting this to be a viable method of tracking structural changes in the XLPE-insulated cable material over extended periods. For the conditions explored, the cable insulation material evaluated did not indicate signs of anomalous aging such as inverse temperature effect in which radiation-induced aging is more severe at lower temperature. Ongoing aging under identical radiation conditions and at lower temperature will further inform conclusions regarding the importance of inverse temperature effects for this material under these conditions.

Radiation Synthesis and Application of Absorbent Hydrogels to Enhance the Quality of Basadiesel

International Nuclear Information System (INIS)

Nguyen Duy Hang; Pham Thi Le Ha; Tran Thi Thuy; Le Hai; Nguyen Tan Man; Le Huu Tu; Nguyen Trong Hoanh Phong; Tran Thi Tam; Tran Thu Hong; Pham Thi Sam; Nguyen Tuong Li Lan

2013-01-01

Studying on the using ability of radiation synthesis hydrogels to enhance the quality of the biodiesel produced from Basa fish oil was implemented. Radiation synthesis of absorbent hydrogels and their application to removal of contaminants from biodiesel produced from fish oil were the major problems. The preparation of the super absorbent hydrogel obtained by radiation induced cross linking of polyacrylamide and polyacrylic was investigated and its application in removal of water, catalyst from the basadiesel emulsion is reported. The hydrogels were characterized in terms of gel content, swelling, character of water and mineral catalyst removal were studied. The effect of temperature, NaOH and KOH content of solution on the swelling degree of hydrogels was also determined. The results showed that the gel fraction of PAAm/PAAc hydrogel with PAAm/AAc (1/4) ratio and dose of 20 kGy was used to synthesized the Gel of A-311. Studies also made on the application of Gel A-311 during the refining process in Basadiesel industry. (author)

Role of neurotensin in radiation-induced hypothermia in rats

International Nuclear Information System (INIS)

Kandasamy, S.B.; Hunt, W.A.; Harris, A.H.

1991-01-01

The role of neurotensin in radiation-induced hypothermia was examined. Intracerebroventricular (ICV) administration of neurotensin produced dose-dependent hypothermia. Histamine appears to mediate neurotensin-induced hypothermia because the mast cell stabilizer disodium cromoglycate and antihistamines blocked the hypothermic effects of neurotensin. An ICV pretreatment with neurotensin antibody attenuated neurotensin-induced hypothermia, but did not attenuate radiation-induced hypothermia, suggesting that radiation-induced hypothermia was not mediated by neurotensin

Pouring and running a protein gel by reusing commercial cassettes.

Science.gov (United States)

Hwang, Alexander C; Grey, Paris H; Cuddy, Katrina; Oppenheimer, David G

2012-02-12

The evaluation of proteins using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis is a common technique used by biochemistry and molecular biology researchers. For laboratories that perform daily analyses of proteins, the cost of commercially available polyacrylamide gels (~$10/gel) can be considerable over time. To mitigate this cost, some researchers prepare their own polyacrylamide gels. Traditional methods of pouring these gels typically utilize specialized equipment and glass gel plates that can be expensive and preclude pouring many gels and storing them for future use. Furthermore, handling of glass plates during cleaning or gel pouring can result in accidental breakage creating a safety hazard, which may preclude their use in undergraduate laboratory classes. Our protocol demonstrates how to pour multiple protein gels simultaneously by recycling Invitrogen Nupage Novex minigel cassettes, and inexpensive materials purchased at a home improvement store. This economical and streamlined method includes a way to store the gels at 4°C for a few weeks. By re-using the plastic gel cassettes from commercially available gels, labs that run frequent protein gels can save significant costs and help the environment. In addition, plastic gel cassettes are extremely resistant to breakage, which makes them ideal for undergraduate laboratory classrooms.

Relationship between radiation induced activation of DNA repair genes and radiation induced apoptosis in human cell line A431

International Nuclear Information System (INIS)

Bom, Hee Seung; Min, Jung Jun; Kim, Kyung Keun; Choi, Keun Hee

2000-01-01

The purpose of this study was to evaluate the relationship between radiation-induced acivation of DNA repair genes and radiation induced apoptosis in A431 cell line. Five and 25 Gys of gamma radiation were given to A431 cells by a Cs-137 cell irradiator. Apoptosis was evaluated by flow cytometry using annexin V-fluorescein isothiocyanate and propidium iodide staining. The expression of DNA repair genes was evaluated by both Northern and Western blot analyses. The number of apoptotic cells increased with the increased radiation dose. It increased most significantly at 12 hours after irradiation. Expression of p53, p21, and ℎRAD50 reached the highest level at 12 hours after 5 Gy irradiation. In response to 25 Gy irradiation, ℎRAD50 and p21 were expressed maximally at 12 hours, but p53 and GADD45 genes showed the highest expression level after 12 hours. Induction of apoptosis and DNA repair by ionizing radiation were closely correlated. The peak time of inducing apoptosis and DNA repair was 12 hours in this study model. ℎRAD50, a recently discovered DNA repair gene, was also associated with radiation-induced apoptosis.=20

Study on radiation-inducible genes

Energy Technology Data Exchange (ETDEWEB)

Lim, Sang Yong; Kim, Dong Ho; Joe, Min Ho; Song, Hyu Npa

2012-01-15

Transcription of previously identified radiation-inducible genes, uscA and cyoA, was examined responding to radiation. The putative promoter regions of both genes were cloned into pRS415 vector containing lacZ, and the core promoter region necessary for radiation response were determined through promoter deletion method. To investigate the role of uscA, which is assumed to be small RNA related with radiation response, a deletion mutant strain of uscA was constructed. However, uscA deletion did not affect bacterial survival against radiation exposure. The use of bacteria as anticancer agents has attracted interest. In this study, we tried to develop tumor targeting bacteria in which the radiation-inducible promoter activate a transgene encoding a cytotoxic protein. For outward secretion of anticancer protein produced inside bacteria, the N-terminal 140 amino acid of SspH1 was found to function as a secretion signal peptide. To create an attenuated tumor-targeting bacteria, Salmonella ptsI mutant strain was constructed, and we found that its virulence decreased. Finally, the tumor-targeting ability of ptsI mutant was verified by the use of in-vivo imaging analysis.

Study on radiation-inducible genes

International Nuclear Information System (INIS)

Lim, Sang Yong; Kim, Dong Ho; Joe, Min Ho; Song, Hyu Npa

2012-01-01

Transcription of previously identified radiation-inducible genes, uscA and cyoA, was examined responding to radiation. The putative promoter regions of both genes were cloned into pRS415 vector containing lacZ, and the core promoter region necessary for radiation response were determined through promoter deletion method. To investigate the role of uscA, which is assumed to be small RNA related with radiation response, a deletion mutant strain of uscA was constructed. However, uscA deletion did not affect bacterial survival against radiation exposure. The use of bacteria as anticancer agents has attracted interest. In this study, we tried to develop tumor targeting bacteria in which the radiation-inducible promoter activate a transgene encoding a cytotoxic protein. For outward secretion of anticancer protein produced inside bacteria, the N-terminal 140 amino acid of SspH1 was found to function as a secretion signal peptide. To create an attenuated tumor-targeting bacteria, Salmonella ptsI mutant strain was constructed, and we found that its virulence decreased. Finally, the tumor-targeting ability of ptsI mutant was verified by the use of in-vivo imaging analysis

Role of endothelium in radiation-induced normal tissue damages

International Nuclear Information System (INIS)

Milliat, F.

2007-05-01

More than half of cancers are treated with radiation therapy alone or in combination with surgery and/or chemotherapy. The goal of radiation therapy is to deliver enough ionising radiation to destroy cancer cells without exceeding the level that the surrounding healthy cells can tolerate. Unfortunately, radiation-induced normal tissue injury is still a dose limiting factor in the treatment of cancer with radiotherapy. The knowledge of normal tissue radiobiology is needed to determine molecular mechanisms involved in normal tissue pathogenic pathways in order to identify therapeutic targets and develop strategies to prevent and /or reduce side effects of radiation therapy. The endothelium is known to play a critical role in radiation-induced injury. Our work shows that endothelial cells promote vascular smooth muscle cell proliferation, migration and fibro-genic phenotype after irradiation. Moreover, we demonstrate for the first time the importance of PAI-1 in radiation-induced normal tissue damage suggesting that PAI-1 may represent a molecular target to limit injury following radiotherapy. We describe a new role for the TGF-b/Smad pathway in the pathogenesis of radiation-induced damages. TGF-b/Smad pathway is involved in the fibro-genic phenotype of VSMC induced by irradiated EC as well as in the radiation-induced PAI-1 expression in endothelial cells. (author)

Modulation of ionizing radiation induced oxidative imbalance by semi-fractionated extract of Piper betle

Science.gov (United States)

Verma, Savita; Dutta, Ajaswrata; Sankhwar, Sanghmitra; Shukla, Sandeep Kumar

2010-01-01

The study was planned to evaluate modulatory effect of aqueous extract of Piper betle leaf (PBL) on ionizing radiation mediated oxidative stress leading to normal tissues damage during radiotherapy and other radiation exposures. The total polyphenols and flavonoids known as free radical scavenger (chelators) were measured in the extract. To ascertain antioxidant potential of PBL extract, we studied free radical scavenging, metal chelation, reducing power, lipid peroxidation inhibition and ferric reducing antioxidant properties (FRAP ) using in vitro assays. Mice were exposed to varied radiation doses administered with the same extract prior to irradiation to confirm its oxidative stress minimizing efficacy by evaluating ferric reducing ability of plasma, reduced glutathione, lipid peroxidation and micro-nuclei frequency. PBL extract was effective in scavenging DPPH (up to 92% at 100 µg/ml) and superoxide radicals (up to 95% at 80 µg/ml), chelated metal ions (up to 83% at 50 µg/ml) and inhibited lipid peroxidation (up to 45.65% at 500 µg/ml) in a dose dependant manner using in vitro model. Oral administration of PBL extract (225 mg/kg body weight) 1 hr before irradiation in mice significantly enhanced (p < 0.01) radiation abated antioxidant potential of plasma and GSH level in all the observed organs. The treatment with extract effectively lowered the radiation induced lipid peroxidation at 24 hrs in all the selected organs with maximum inhibition in thymus (p < 0.01). After 48 hrs, lipid peroxidation was maximally inhibited in the group treated with the extract. Frequency of radiation induced micronucleated cells declined significantly (34.78%, p < 0.01) at 24 hrs post-irradiation interval by PBL extract administration. The results suggest that PBL extract has high antioxidant potential and relatively non-toxic and thus could be assertively used to mitigate radiotherapy inflicted normal tissues damage and also injuries caused by moderate doses of radiation

Influence of the gel thickness on in vivo hyaline cartilage regeneration induced by double-network gel implanted at the bottom of a large osteochondral defect: short-term results.

Science.gov (United States)

Matsuda, Hidetoshi; Kitamura, Nobuto; Kurokawa, Takayuki; Arakaki, Kazunobu; Gong, Jian Ping; Kanaya, Fuminori; Yasuda, Kazunori

2013-01-31

A double-network (DN) gel, which is composed of poly(2-acrylamido-2-methylpropanesulfonic acid) and poly(N,N'-dimethyl acrylamide), can induce hyaline cartilage regeneration in vivo in a large osteochondral defect. The purpose of this study was to clarify the influence of the thickness of the implanted DN gel on the induction ability of hyaline cartilage regeneration. Thirty-eight mature rabbits were used in this study. We created an osteochondral defect having a diameter of 4.3-mm in the patellofemoral joint. The knees were randomly divided into 4 groups (Group I: 0.5-mm thick gel, Group II: 1.0-mm thick gel, Group III: 5.0-mm thick gel, and Group IV: untreated control). Animals in each group were further divided into 3 sub-groups depending on the gel implant position (2.0-, 3.0-, or 4.0-mm depth from the articular surface) in the defect. The regenerated tissues were evaluated with the Wayne's gross and histological grading scales and real time PCR analysis of the cartilage marker genes at 4 weeks. According to the total Wayne's score, when the depth of the final vacant space was set at 2.0 mm, the scores in Groups I, II, and III were significantly greater than that Group IV (phyaline cartilage regeneration as the 5.0-mm thick DN gel plug. However, the induction ability of the 0.5-mm thick sheet was significantly lower when compared with the 1.0-mm thick gel sheet. The 1.0-mm DN gel sheet is a promising device to establish a cell-free cartilage regeneration strategy that minimizes bone loss from the gel implantation.

Effect of gamma radiation on silica gel, (3)

International Nuclear Information System (INIS)

Ogura, Hajime; Nakazato, Chiyoko; Kondo, Masaharu; Sawai, Teruko; Sawai, Takeshi.

1979-01-01

The γ-irradiation of silica gel degassed for 24 h above 400 0 C produces visible color center (lambda sub(max) = 530 nm). The color center instantly disappears on exposure to H 2 at room temperature and irreversible adsorption of H 2 is concurrently observed. On the basis that color center is attributed to the positive hole due to substitutional impurity of Al in silica matrix, the yield of color center and H 2 adsorption have been investigated as a function of Al content in silica gel deliberatly prepared by us from silicon tetrachloride to contain Al in the range of 10 -3 -- 5w/0. Absorbance at 530 nm, A 530 , due to color center as well as the amount of H 2 adsorbed, (H 2 )sub(ads), increase with the Al content in the matrix. A 530 /(H 2 )sub(ads) is 1.0 x 10 6 (O.D. unit g/mol) in these gels. This ratio is seen almost same with two samples of gel commercially available. By assuming that 1 mol of H 2 reacts with 2 mol of positive hole, the extinction coefficient of color center at 530 nm is evaluated as 1.0 x 10 6 (g/mol.cm). (author)

Heavy-ion radiation induced bystander effect in mice

Science.gov (United States)

Liang, Shujian; Sun, Yeqing; Zhang, Meng; Wang, Wei; Cui, Changna

2012-07-01

Radiation-induced bystander effect is defined as the induction of damage in neighboring non-hit cells by signals released from directly-irradiated cells. Recently, Low dose of high LET radiation induced bystander effects in vivo have been reported more and more. It has been indicated that radiation induced bystander effect was localized not only in bystander tissues but also in distant organs. Genomic, epigenetic, metabolomics and proteomics play significant roles in regulating heavy-ion radiation stress responses in mice. To identify the molecular mechanism that underlies bystander effects of heavy-ion radiation, the male mice head were exposed to 2000mGy dose of 12C heavy-ion radiation and the distant organ liver was detected on 1h, 6h, 12h and 24h after radiation, respectively. MSAP was used to monitor the level of polymorphic DNA methylation changes. The results show that heavy-ion irradiate mouse head can induce liver DNA methylation changes significantly. The percent of DNA methylation changes are time-dependent and highest at 6h after radiation. We also prove that the hypo-methylation changes on 1h and 6h after irradiation. But the expression level of DNA methyltransferase DNMT3a is not changed. UPLC/Synapt HDMS G2 was employed to detect the proteomics of bystander liver 1h after irradiation. 64 proteins are found significantly different between treatment and control group. GO process show that six of 64 which were unique in irradiation group are associated with apoptosis and DNA damage response. The results suggest that mice head exposed to heavy-ion radiation can induce damage and methylation pattern changed in distant organ liver. Moreover, our findings are important to understand the molecular mechanism of radiation induced bystander effects in vivo.

A study of radiation-induced cerebral vascular injury in nasopharyngeal carcinoma patients with radiation-induced temporal lobe necrosis.

Directory of Open Access Journals (Sweden)

Jianhong Ye

Full Text Available To investigate radiation-induced carotid and cerebral vascular injury and its relationship with radiation-induced temporal lobe necrosis in nasopharyngeal carcinoma (NPC patients.Fifty eight NPC patients with radiation-induced temporal lobe necrosis (TLN were recruited in the study. Duplex ultrasonography was used to scan bilateral carotid arterials to evaluate the intima-media thickness (IMT and occurrence of plaque formation. Flow velocities of bilateral middle cerebral arteries (MCAs, internal carotid arteries (ICAs and basal artery (BA were estimated through Transcranial Color Doppler (TCD. The results were compared with data from 33 patients who were free from radiation-induced temporal lobe necrosis after radiotherapy and 29 healthy individuals.Significant differences in IMT, occurrence of plaques of ICAs and flow velocities of both MCAs and ICAs were found between patients after radiotherapy and healthy individuals (p<0.05. IMT had positive correlation with post radiation interval (p = 0.049. Compared with results from patients without radiation-induced TLN, the mean IMT was significantly thicker in patients with TLN (p<0.001. Plaques were more common in patients with TLN than patients without TLN (p = 0.038. In addition, flow velocities of MCAs and ICAs in patients with TLN were much faster (p<0.001, p<0.001. Among patients with unilateral TLN, flow velocity of MCAs was significantly different between ipsilateral and contralateral sides to the lesion (p = 0.001.Thickening of IMT, occurrence of plaque formation and hemodynamic abnormality are more common in patients after radiotherapy, especially in those with TLN, compared with healthy individuals.

Radiation-induced heart injury. Radiopathological study

Energy Technology Data Exchange (ETDEWEB)

Suzuki, Y; Niibe, H [Gunma Univ., Maebashi (Japan). School of Medicine

1975-11-01

In order to identify radiation-induced heart injury and to differentiate it from heart disease, an attempt was made to clarify post-irradiation heart injury by investigating the histological changes which occur during the interval between the irradiation and the time of demonstrable histological changes. A study was made of 83 autopsies in which most of the primary neoplasms were breast cancers, lung cancers and mediastinal tumors. In 43 of these autopsies the heart had been irradiated. Sixty eight dd-strain mice were also used for microautoradiographic study. Histological changes in the heart were observed in 27 of the 43 cases receiving irradiation. The limit of the tolerance dose to the heart for indicating histological changes was 1220 ret in humans. The latent period without histological changes was 2.7 months after initiation of radiation therapy. Greater heart injury was observed after re-irradiation or after the combined therapy of radiation and chemotherapy especially mitomycin (MMC). The histological findings after treatment with MMC were similar to those of radiation-induced heart injury. Results of the study indicate that the damage is secondary to radiation-induced changes of the vascula connective tissue.

Interval for the expression of the adaptive response induced by gamma radiation in leucocytes of mouse In vivo

International Nuclear Information System (INIS)

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

2002-01-01

The interval between the adaptive gamma radiation dose (0.01 Gy) and challenge (1.0 Gy) capable to induce the maximum expression of the adaptive response in lymphocytes of mouse In vivo. The animals were exposed to the mentioned doses with different intervals among both (1, 1.5, 5 or 18 hr). By means of the unicellular electrophoresis in gel technique, four damage parameters were analysed. The results showed that from the 1 hr interval an adaptive response was produced since in the pretreated organisms with 0.01 Gy the cells present lesser damage than in those not adapted. The maximum response was induced with the intervals between 2.5 and 5 hr and even though it persisted until 18 hr, the effect was reducing. (Author)

Magneto-dependent stress relaxation of magnetorheological gels

KAUST Repository

Xu, Yangguang; Liu, Taixiang; Liao, G J; Lubineau, Gilles

2017-01-01

The stress relaxation behaviors of magnetorheological (MR) gels under stepwise shear loading are systematically investigated. The particle-enhanced effect, the magneto-induced effect, and the temperature-enhanced effect on the stress relaxation of MR gels are discussed. For further analysis of the magneto-induced stress relaxation mechanism in MR gels, a phenomenological model is established to describe the stress relaxation behavior of the matrix and the magnetic particle chains. All characteristic parameters introduced in the model, i.e. relaxation time, instantaneous modulus, and stable modulus, have well-defined physical meanings and are fitted based on the experimental results. The influence of each parameter on the macroscopic response is discussed and it is found that the relaxation stress induced by the magneto-mechanical coupling effect plays an important role in the stress relaxation process of MR gels.

Magneto-dependent stress relaxation of magnetorheological gels

KAUST Repository

Xu, Yangguang

2017-09-01

The stress relaxation behaviors of magnetorheological (MR) gels under stepwise shear loading are systematically investigated. The particle-enhanced effect, the magneto-induced effect, and the temperature-enhanced effect on the stress relaxation of MR gels are discussed. For further analysis of the magneto-induced stress relaxation mechanism in MR gels, a phenomenological model is established to describe the stress relaxation behavior of the matrix and the magnetic particle chains. All characteristic parameters introduced in the model, i.e. relaxation time, instantaneous modulus, and stable modulus, have well-defined physical meanings and are fitted based on the experimental results. The influence of each parameter on the macroscopic response is discussed and it is found that the relaxation stress induced by the magneto-mechanical coupling effect plays an important role in the stress relaxation process of MR gels.

Radiation-induced degradation of pollutants

International Nuclear Information System (INIS)

Proksch, E.

1988-01-01

This article outlines the fundamentals of radiation-induced degradation of noxious substances in drinking water and waste water and discusses the relevant literature. Radiation methods present a number of advantages and disadvantages, which should carefully be considered in each case. In many cases, there seems to be merit in combining the radiation method with other techniques, as e.g. ozone treatement and biodegradation. 30 refs., 3 figs. (Author)

Gel-free proteomics reveal potential biomarkers of priming-induced salt tolerance in durum wheat.

Science.gov (United States)

Fercha, Azzedine; Capriotti, Anna Laura; Caruso, Giuseppe; Cavaliere, Chiara; Gherroucha, Hocine; Samperi, Roberto; Stampachiacchiere, Serena; Lagana, Aldo

2013-10-08

Seed priming has been successfully demonstrated to be an efficient method to improve crop productivity under stressful conditions. As a first step toward better understanding of the mechanisms underlying the priming-induced salt stress tolerance in durum wheat, and to overcome the limitations of the gel-based approach, a comparative gel-free proteomic analysis was conducted with durum wheat seed samples of varying vigor as generated by hydro- and ascorbate-priming treatments. Results indicate that hydro-priming was accompanied by significant changes of 72 proteins, most of which are involved in proteolysis, protein synthesis, metabolism and disease/defense response. Ascorbate-priming was, however, accompanied by significant changes of 83 proteins, which are mainly involved in protein metabolism, antioxidant protection, repair processes and, interestingly, in methionine-related metabolism. The present study provides new information for understanding how 'priming-memory' invokes seed stress tolerance. The current work describes the first study in which gel-free shotgun proteomics were used to investigate the metabolic seed protein fraction in durum wheat. A combined approach of protein fractionation, hydrogel nanoparticle enrichment technique, and gel-free shotgun proteomic analysis allowed us to identify over 380 proteins exhibiting greater molecular weight diversity (ranging from 7 to 258kDa). Accordingly, we propose that this approach could be useful to acquire a wider perspective and a better understanding of the seed proteome. In the present work, we employed this method to investigate the potential biomarkers of priming-induced salt tolerance in durum wheat. In this way, we identified several previously unrecognized proteins which were never been reported before, particularly for the ascorbate-priming treatment. These findings could provide new avenues for improving crop productivity, particularly under unfavorable environmental conditions. © 2013.

Radiation effects on the immiscible polymer blend of nylon1010 and high-impact polystyrene (HIPS) I: Gel/dose curves, mathematical expectation theorem and thermal behaviour

International Nuclear Information System (INIS)

Dong, W.; Zhang, W.; Chen, G.; Liu, J.

2000-01-01

This paper studies the radiation properties of the immiscible blend of nylon1010 and HIPS. The gel fraction increased with increasing radiation dose. The network was found mostly in nylon1010, the networks were also found in both nylon1010 and HIPS when the dose reaches 0.85 MGy or more. We used the equation and the modified Zhang-Sun-Qian equation to simulate the relationship with the dose and the sol fraction. The latter equation fits well with these polymer blends and the relationship used by it showed better linearity than the one by the equation. We also studied the conditions of formation of the network by the mathematical expectation theorem for the binary system. Thermal properties of polymer blend were observed by DSC curves. The crystallization temperature decreases with increasing dose because the cross-linking reaction inhibited the crystallization procession and destroyed the crystals. The melting temperature also reduced with increasing radiation dose. The dual melting peak gradually shifted to single peak and the high melting peak disappeared at high radiation dose. However, the radiation-induced crystallization was observed by the heat of fusion increasing at low radiation dose. On the other hand, the crystal will be damaged by radiation. A similar conclusion may be drawn by the DSC traces when the polymer blends were crystallized. When the radiation dose increases, the heat of fusion reduces dramatically and so does the heat of crystallization. (author)

Pyruvate metabolism: A therapeutic opportunity in radiation-induced skin injury

Energy Technology Data Exchange (ETDEWEB)

Yoo, Hyun; Kang, Jeong Wook [Department of Radiation Oncology, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Lee, Dong Won [Department of Plastic Surgery, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Oh, Sang Ho [Department of Dermatology, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Lee, Yun-Sil [College of Pharmacy & Division of Life and Pharmaceutical Sciences, Ewah Womans University, Seoul 120-750 (Korea, Republic of); Lee, Eun-Jung [Department of Radiation Oncology, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Cho, Jaeho, E-mail: jjhmd@yuhs.ac [Department of Radiation Oncology, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of)

2015-05-08

Ionizing radiation is used to treat a range of cancers. Despite recent technological progress, radiation therapy can damage the skin at the administration site. The specific molecular mechanisms involved in this effect have not been fully characterized. In this study, the effects of pyruvate, on radiation-induced skin injury were investigated, including the role of the pyruvate dehydrogenase kinase 2 (PDK2) signaling pathway. Next generation sequencing (NGS) identified a wide range of gene expression differences between the control and irradiated mice, including reduced expression of PDK2. This was confirmed using Q-PCR. Cell culture studies demonstrated that PDK2 overexpression and a high cellular pyruvate concentration inhibited radiation-induced cytokine expression. Immunohistochemical studies demonstrated radiation-induced skin thickening and gene expression changes. Oral pyruvate treatment markedly downregulated radiation-induced changes in skin thickness and inflammatory cytokine expression. These findings indicated that regulation of the pyruvate metabolic pathway could provide an effective approach to the control of radiation-induced skin damage. - Highlights: • The effects of radiation on skin thickness in mice. • Next generation sequencing revealed that radiation inhibited pyruvate dehydrogenase kinase 2 expression. • PDK2 inhibited irradiation-induced cytokine gene expression. • Oral pyruvate treatment markedly downregulated radiation-induced changes in skin thickness.

A phase III trial comparing an anionic phospholipid-based cream and aloe vera-based gel in the prevention of radiation dermatitis in pediatric patients

International Nuclear Information System (INIS)

Merchant, Thomas E; Bosley, Christina; Smith, Julie; Baratti, Pam; Pritchard, David; Davis, Tina; Li, Chenghong; Xiong, Xiaoping

2007-01-01

Radiation dermatitis is a common side effect of radiation therapy (RT). In severe cases, RT must be interrupted until the skin heals, which can compromise treatment. The purpose of the study was to compare an anionic polar phospholipid (APP)-based cream and an aloe vera-based gel to determine their effectiveness in preventing and treating radiation dermatitis. Forty-five pediatric patients (median age, 11 years) with various diagnoses who received at least 23.4 Gy participated. APP cream and aloe vera gel were symmetrically applied within the irradiated field after each treatment. Three measures were collected before, during and after completion of treatment: subject's skin comfort, dermatologic assessment, and common toxicity criteria (CTC). Significant differences in specific variables favoring APP cream use were noted in some patients including skin comfort variables, dry (p = 0.002), soft (p = 0.057), feels good (p = 0.002), rough (p = 0.065), smooth (p = 0.012) and dermatologic variables, dryness (p = 0.013), erythema (p = 0.002) and peely (p = 0.008). Grouped CTC scores were supportive of APP cream (p = 0.004). In comparing the first and last assessments, two dermatologic variables, dryness (p = 0.035) and peely (p = 0.016), favored APP cream. APP cream is more effective than aloe vera-based gel for prevention and treatment of radiation dermatitis

Water equivalence of polymer gel dosimeters

International Nuclear Information System (INIS)

Sellakumar, P.; James Jebaseelan Samuel, E.; Supe, Sanjay S.

2007-01-01

To evaluate the water equivalence and radiation transport properties of polymer gel dosimeters over the wide range of photon and electron energies 14 different types of polymer gels were considered. Their water equivalence was evaluated in terms of effective atomic number (Z eff ), electron density (ρ e ), photon mass attenuation coefficient (μ/ρ), photon mass energy absorption coefficient (μ en /ρ) and total stopping power (S/ρ) tot of electrons using the XCOM and the ESTAR database. The study showed that the effective atomic number of polymer gels were very close ( en /ρ for all polymer gels were in close agreement ( tot of electrons in polymer gel dosimeters were within 1% agreement with that of water. From the study we conclude that at lower energy (<80keV) the polymer gel dosimeters cannot be considered water equivalent and study has to be carried out before using the polymer gel for clinical application

Konjac flour improved textural and water retention properties of transglutaminase-mediated, heat-induced porcine myofibrillar protein gel: Effect of salt level and transglutaminase incubation.

Science.gov (United States)

Chin, Koo B; Go, Mi Y; Xiong, Youling L

2009-03-01

Functional properties of heat-induced gels prepared from microbial transglutaminase (TG)-treated porcine myofibrillar protein (MP) containing sodium caseinate with or without konjac flour (KF) under various salt concentrations (0.1, 0.3 and 0.6MNaCl) were evaluated. The mixed MP gels with KF exhibited improved cooking yields at all salt concentrations. TG treatment greatly enhanced gel strength and elasticity (storage modulus, G') at 0.6M NaCl, but not at lower salt concentrations. The combination of KF and TG improved the gel strength at 0.1 and 0.3M NaCl and G' at all salt concentrations, when compared with non-TG controls. Incubation of MP suspensions (sols) with TG promoted the disappearance of myosin heavy chain and the production of polymers. The TG-treated MP mixed gels had a compact structure, compared to those without TG, and the KF incorporation modified the gel matrix and increased its water-holding capacity. Results from differential scanning calorimetry suggested possible interactions of MP with KF, which may explain the changes in the microstructure of the heat-induced gels.

Vaginal prostaglandin gel to induce labour in women with one previous caesarean section.

LENUS (Irish Health Repository)

Agnew, G

2012-02-01

This retrospective study reviewed the mode of delivery when vaginal prostaglandins were used to induce labour in women with a single previous lower segment caesarean section. Over a 4-year period, PGE 2 gel was used cautiously in low doses in 54 women. Induction with PGE 2 gel was associated with an overall vaginal birth after caesarean section (VBAC) rate of 74%, which compared favourably with the 74% VBAC rate in women who went into spontaneous labour (n = 1969). There were no adverse outcomes recorded after the prostaglandin inductions but the number reported are too small to draw any conclusions about the risks, such as uterine rupture. We report our results because they may be helpful in assessing the chances of a successful VBAC in the uncommon clinical circumstances where prostaglandin induction is being considered.

Creation of Dosimetric Verification for Implementation of Intensity Modulated Radiation Therapy (IMRT) Validates Using Polymer Gel

International Nuclear Information System (INIS)

Mansour, M.Sh.E.

2015-01-01

Polymer gel dosimeter is a technique that has the ability to map absorbed radiation dose distributions in three dimensions (3D) with high spatial resolution, it offers a number of advantages over traditional dosimeters such as ionization chambers, thermo luminescent dosimeters (TLD) and radiographic film. These gels are reproducible in response and stable 0 n post-irradiation. It is used as the monomer N-iso propyl acryl amide (NIPAM) and N, N- methylene bis acryl amide (Bis) as the cross linker. A historical overview of gel dosimeter was discussed in detail, inside the theses this case; nearly all data met the expected measurement error of 5 % of the maximum dose (50 c Gy). Relative errors were determined to decrease from 25 % at a 2 Gy irradiation to 9.2% for a 10 Gy irradiation The NIPAM polymer gel dosimeter system proved to be an invaluable method for the quantification of the 3-D dose distribution provided by IMRT. A measurement error of less than 5% was achieved. Toxicity and uncertain response to particular environmental characteristics (i.e., temperature and aging) upon the gel are of important concern about the use of the gel at this time. A PAG gel dosimeter is a method verifying dose delivered for prostate cancer radiotherapy treatment, which has been evaluated in this work. A comparison of DVH for PTV between the two treatment plans was verified experimentally. MRI response, the possibility was demonstrated of manufacturing gel dosimeters suitable for 3D dosimeter in the dose range. The results show that IMRT technique not only provides a better conformal dose to the prostate target volume than conventional Seven-field technique, but also reduces doses to the surrounding normal tissues, The aim of this study was to investigate the basic characteristics of the modified gel dosimeter such as temperature effects, magnetic field strength, Ph, aging, energy and dose rate dependence This includes studies of relaxation time dose response, and stability of the

Radiation-induced Genomic Instability and Radiation Sensitivity

Energy Technology Data Exchange (ETDEWEB)

Varnum, Susan M.; Sowa, Marianne B.; Kim, Grace J.; Morgan, William F.

2013-01-19

The obvious relationships between reactive oxygen and nitrogen species, mitochondrial dysfunction, inflammatory type responses and reactive chemokines and cytokines suggests a general stress response induced by ionizing radiation most likely leads to the non-targeted effects described after radiation exposure. We argue that true bystander effects do not occur in the radiation therapy clinic. But there is no question that effects outside the target volume do occur. These “out of field effects” are considered very low dose effects in the context of therapy. So what are the implications of non-targeted effects on radiation sensitivity? The primary goal of therapy is to eradicate the tumor. Given the genetic diversity of the human population, lifestyle and environment factors it is likely some combination of these will influence patient outcome. Non-targeted effects may contribute to a greater or lesser extent. But consider the potential situation involving a partial body exposure due to a radiation accident or radiological terrorism. Non-targeted effects suggest that the tissue at risk for demonstrating possible detrimental effects of radiation exposure might be greater than the volume actually irradiated.

Basic reactions induced by radiation

International Nuclear Information System (INIS)

Charlesby, A.

1980-01-01

This paper summarises some of the basic reactions resulting from exposure to high energy radiation. In the initial stages energy is absorbed, but not necessarily at random, giving radical and ion species which may then react to promote the final chemical change. However, it is possible to intervene at intermediate stages to modify or reduce the radiation effect. Under certain conditions enhanced reactions are also possible. Several expressions are given to calculate radiation yield in terms of energy absorbed. Some analogies between radiation-induced reactions in polymers, and those studied in radiobiology are outlined. (author)

Silica scintillating materials prepared by sol-gel methods

International Nuclear Information System (INIS)

Werst, D.W.; Sauer, M.C. Jr.; Cromack, K.R.; Lin, Y.; Tartakovsky, E.A.; Trifunac, A.D.

1993-01-01

Silica was investigated as a rad-hard alternative to organic polymer hosts for organic scintillators. Silica sol-gels were prepared by hydrolysis of tetramethoxysilane in alcohol solutions. organic dyes were incorporated into the gels by dissolving in methanol at the sol stage of gel formation. The silica sol-gel matrix is very rad-hard. The radiation stability of silica scintillators prepared by this method is dye-limited. Transient radioluminescence was measured following excitation with 30 ps pulses of 20 MeV electrons

Radiation-Induced Differentiation in Human Lung Fibroblast

International Nuclear Information System (INIS)

Park, Sa-Rah; Ahn, Ji-Yeon; Han, Young-Soo; Shim, Jie-Young; Yun, Yeon-Sook; Song, Jie-Young

2007-01-01

One of the most common tumors in many countries is lung cancer and patients with lung cancer may take radiotherapy. Although radiotherapy may have its own advantages, it can also induce serious problems such as acute radiation pneumonitis and pulmonary fibrosis. Pulmonary fibrosis is characterized by excessive production of α-SMA and accumulation of extracellular matrix (ECM) such as collagen and fibronectin. There has been a great amount of research about fibrosis but the exact mechanism causing the reaction is not elucidated especially in radiation-induced fibrosis. Until now it has been known that several factors such as transforming growth factor (TGF-β), tumor necrosis factor (TNF), interleukin (IL)-1, IL-6, platelet-derived growth factor (PDGF) and fibroblast growth factor (FGF) are related to fibrosis. Among them TGF-β with Smad signaling is known to be the main stream and other signaling molecules such as MAPK, ERK and JNK (3) also participates in the process. In addition to those above factors, it is thought that more diverse and complicate mechanisms may involve in the radiationinduced fibrosis. Therefore, to investigate the underlying mechanisms in radiation induced fibrosis, first of all, we confirmed whether radiation induces trans differentiation in human normal lung fibroblasts. Here, we suggest that not only TGF-β but also radiation can induce trans differentiation in human lung fibroblast WI-38 and IMR-90

Radiation-Induced Alopecia after Endovascular Embolization under Fluoroscopy

Directory of Open Access Journals (Sweden)

Vipawee Ounsakul

2016-01-01

Full Text Available Radiation-induced alopecia after fluoroscopically guided procedures is becoming more common due to an increasing use of endovascular procedures. It is characterized by geometric shapes of nonscarring alopecia related to the area of radiation. We report a case of a 46-year-old man presenting with asymptomatic, sharply demarcated rectangular, nonscarring alopecic patch on the occipital scalp following cerebral angiography with fistula embolization under fluoroscopy. His presentations were compatible with radiation-induced alopecia. Herein, we also report a novel scalp dermoscopic finding of blue-grey dots in a target pattern around yellow dots and follicles, which we detected in the lesion of radiation-induced alopecia.

Directed shift of vaginal microbiota induced by vaginal application of sucrose gel in rhesus macaques

Directory of Open Access Journals (Sweden)

Kai-tao Hu

2015-04-01

Conclusions: Rhesus macaques can be used as animal models of bacterial vaginosis to develop drugs and test treatment efficacy. Furthermore, the topical application of sucrose gel induced the shifting of vaginal flora of rhesus macaques from a BV kind of flora to a lactobacilli-dominating flora.

Clinical evaluation of the intraoral fluoride releasing system in radiation-induced xerostomic subjects. Part 2: Phase I study.

Science.gov (United States)

Chambers, Mark S; Mellberg, James R; Keene, Harris J; Bouwsma, Otis J; Garden, Adam S; Sipos, Tibor; Fleming, Terence J

2006-10-01

Radiation-induced xerostomia can result in the rapid onset and progression of dental caries in head and neck cancer patients. Topically applied fluorides have been successfully used to inhibit the formation of dental caries in this population. However, because intensive daily self-application is required, compliance is an issue. The intraoral fluoride-releasing system (IFRS) containing a sodium fluoride core is a newly developed, sustained-release, passive drug delivery system that does not require patient involvement except for periodic replacement, thus reducing the effect of patient compliance on its effectiveness in dental caries prevention. Twenty-two head and neck cancer patients from U. T. M. D. Anderson Cancer Center, with radiation-induced xerostomia, were entered into a pilot study to contrast the daily home use of a 0.4% stannous fluoride-gel-containing tray (control group) to IFRS (study group) with respect to tolerability and adherence, and to obtain information on relative caries preventive efficacy. Participants were stratified on the basis of radiation exposure and randomly assigned to treatment with either IFRS or stannous fluoride gel. Patients in both groups were fitted with two IFRS retainers and also were instructed to use a 1100-ppm fluoride conventional sodium fluoride dentifrice twice daily. The study was conducted as a single-blinded, parallel-cell trial. Pre-existing carious lesions were restored prior to the beginning of the study. The efficacy variable was determined by the mean number of new or recurrent decayed surfaces. Patients were examined for caries 4, 8, 12, 24, 36, and 48 weeks after initiation of treatment. Reports of adverse reactions were based on information volunteered by patients and that were elicited during interviews. At baseline, the resting and stimulated salivary flow rates (g/5min) were significantly greater in the control group than in the study group (pIFRS groups during the study period. The rate of new or

Acoustic evaluation of polymer gel dosimeters

International Nuclear Information System (INIS)

Mather, M.L.; De Deene, Y.; Baldock, C.; Whittaker, A.K.

2002-01-01

Advances in radiotherapy treatment techniques such as intensity modulated radiotherapy are placing increasing demands on radiation dosimetry for verification of dose distributions in 3D. In response, polymer gel dosimeters that are capable of recording dose distributions in 3D are currently being developed. Recently, a new technique for evaluation of absorbed dose distributions in these dosimeters using ultrasound was introduced. The current work aims to demonstrate the potential of ultrasound as an evaluation technique for polymer gel dosimeters and to investigate the ultrasound properties of two different dosimeter formulations, PAG and MAGIC gels

Radiation-induced neuropathies: collateral damage of improved cancer prognosis

International Nuclear Information System (INIS)

Pradat, Pierre-Francois; Maisonobe, Thierry; Psimaras, Dimitri; Lenglet, Timothee; Porcher, Raphael; Lefaix, J.L.; Delenian, S.

2012-01-01

Because of the improvement of cancer prognosis, long-term damages of treatments become a medical and public health problem. Among the iatrogenic complications, neurological impairment is crucial to consider since motor disability and pain have a considerable impact on quality of life of long cancer survivors. However, radiation-induced neuropathies have not been the focus of great attention. The objective of this paper is to provide an updated review about the radiation-induced lesions of the peripheral nerve system. Radiation-induced neuropathies are characterized by their heterogeneity in both symptoms and disease course. Signs and symptoms depend on the affected structures of the peripheral nerve system (nerve roots, nerve plexus or nerve trunks). Early-onset complications are often transient and late complications are usually progressive and associated with a poor prognosis. The most frequent and well known is delayed radiation-induced brachial plexopathy, which may follow breast cancer irradiation. Radiation-induced lumbosacral radiculoplexopathy is characterized by pure or predominant lower motor neuron signs. They can be misdiagnosed, confused with amyotrophic lateral sclerosis (ALS) or with leptomeningeal metastases since nodular MRI enhancement of the nerve roots of the cauda equina and increased cerebrospinal fluid protein content can be observed. In the absence of specific markers of the link with radiotherapy, the diagnosis of post-radiation neuropathy may be difficult. Recently, a posteriori conformal radiotherapy with 3D dosimetric reconstitution has been developed to link a precise anatomical site to unexpected excess irradiation. The importance of early diagnosis of radiation-induced neuropathies is underscored by the emergence of new disease-modifying treatments. Although the pathophysiology is not fully understood, it is already possible to target radiation-induced fibrosis but also associated factors such as ischemia, oxidative stress and

Radiation induced mitotic delay and stimulation of growth

International Nuclear Information System (INIS)

Feldmann, A.

1974-01-01

The mechanisms responsible for the radiation induced mitotic delay and stimulation of growth are discussed in connection with the results of studies in Lemna minor and Lepidium sativum. The action of temperature seems to be of major importance. As many authors suggest that various chemical agents and slight intoxications also affect mitosis in a way similar to that induced by ionizing radiation, the radiation induced stimulation has lost its specific character and approaches might be found for further investigations of this phenomenon. (MG) [de

Radiation-induced apoptosis in F9 teratocarcinoma cells

International Nuclear Information System (INIS)

Langley, R.E.; Palayoor, S.T.; Coleman, C.N.; Bump, E.A.

1994-01-01

We have found that F9 murine teratocarcinoma cells undergo morphological changes and internucleosomal DNA fragmentation characteristic of apoptosis after exposure to ionizing radiation. We studied the time course, radiation dose-response, and the effects of protein and RNA synthesis inhibitors on this process. The response is dose dependent in the range 2-12 Gy. Internucleosomal DNA fragmentation can be detected as early as 6 h postirradiation and is maximal by 48 h. Cycloheximide, a protein synthesis inhibitor, and 5,6-dichloro-1-β-D-ribofuranosylbenzimidazole, an RNA synthesis inhibitor, both induced internucleosomal DNA fragmentation in the unirradiated cells and enhanced radiation-induced DNA fragmentation. F9 cells can be induced to differentiate into cells resembling endoderm with retinoic acid. After irradiation, differentiated F9 cells exhibit less DNA fragmentation than stem cells. This indicates that ionizing radiation can induce apoptosis in non-lymphoid tumours. We suggest that embryonic tumour cells may be particularly susceptible to agents that induce apoptosis. (Author)

Radiation-induced apoptosis in F9 teratocarcinoma cells

Energy Technology Data Exchange (ETDEWEB)

Langley, R E; Palayoor, S T; Coleman, C N; Bump, E A [Joint Center for Radiation Therapy and Dana Farber Cancer Inst., Boston (United States)

1994-05-01

We have found that F9 murine teratocarcinoma cells undergo morphological changes and internucleosomal DNA fragmentation characteristic of apoptosis after exposure to ionizing radiation. We studied the time course, radiation dose-response, and the effects of protein and RNA synthesis inhibitors on this process. The response is dose dependent in the range 2-12 Gy. Internucleosomal DNA fragmentation can be detected as early as 6 h postirradiation and is maximal by 48 h. Cycloheximide, a protein synthesis inhibitor, and 5,6-dichloro-1-[beta]-D-ribofuranosylbenzimidazole, an RNA synthesis inhibitor, both induced internucleosomal DNA fragmentation in the unirradiated cells and enhanced radiation-induced DNA fragmentation. F9 cells can be induced to differentiate into cells resembling endoderm with retinoic acid. After irradiation, differentiated F9 cells exhibit less DNA fragmentation than stem cells. This indicates that ionizing radiation can induce apoptosis in non-lymphoid tumours. We suggest that embryonic tumour cells may be particularly susceptible to agents that induce apoptosis. (Author).

Radiation induced crosslinking of polytetrafluoroethylene

International Nuclear Information System (INIS)

Oshima, Akihiro; Tabata, Yoneho; Ikeda, Shigetoshi; Otsuhata, Kazushige; Kudoh, Hisaaki; Seguchi, Tadao.

1995-01-01

The Irradiation temperature effect on polytetrafluoroethylene (PTFE) from room temperature to 380degC was investigated by tensile test and thermal analysis. The behavior of tensile properties and changes of crystallinity on irradiation indicated the formation of a network structure in PTFE by radiation induced crosslinking in inert gas in the molten state just above the melting temperature of PTFE (327degC). The crosslinked PTFE showed a much improved radiation resistance in an atmospheric radiation field. (author)

Study of radiation-induced chromosomal aberrations

International Nuclear Information System (INIS)

Wolfring, E.

2004-06-01

A method for determining chromosomal aberrations was established for the purpose of examining the relative biological effectiveness (RBE) of photon radiation with respect to mammary epithelium cells. Cells were exposed to 25 kV X-radiation and to 200 kV X-radiation for comparison and the resulting concentrations of chromosomal aberrations were compared. The RBE M value for radiation-induced fragmentation was found to be 4.2 ± 2.4, while the RBE M value for radiation-induced generation of dicentric chromosomes was found to be 0.5 ± 0.5. In addition to the evaluation of chromosomal aberrations the number of cell cycles undergone by the cells was monitored by means of BrDU staining. As expected, the proportion of cells which underwent more than one cell cycle following exposure to 5 Gy was very low in both cases, amounting to 1.9% (25 kV) and 3.2 (200 kV). Non-radiated cells yielded control values of 26.0% and 12.6%, suggesting variations in external conditions from day to day

Cell cycle arrest induced by radiation

International Nuclear Information System (INIS)

Okaichi, Yasuo; Matsumoto, Hideki; Ohnishi, Takeo

1994-01-01

It is known that various chemical reactions, such as cell cycle arrest, DNA repair and cell killing, can occur within the cells when exposed to ionizing radiation and ultraviolet radiation. Thus protein dynamics involved in such chemical reactions has received considerable attention. In this article, cell cycle regulation is first discussed in terms of the G2/M-phase and the G1/S-phase. Then, radiation-induced cell cycle arrest is reviewed. Cell cycle regulation mechanism involved in the G2 arrest, which is well known to occur when exposed to radiation, has recently been investigated using yeasts. In addition, recent study has yielded a noticeable finding that the G1 arrest can occur with intracellular accumulation of p53 product following ionization radiation. p53 is also shown to play an extremely important role in both DNA repair and cell killing due to DNA damage. Studies on the role of genes in protein groups induced by radiation will hold promise for the elucidation of cell cycle mechanism. (N.K.) 57 refs

Control of radiation-induced diarrhea with cholestyramine

International Nuclear Information System (INIS)

Heusinkveld, R.S.; Manning, M.R.; Aristizabal, S.A.

1978-01-01

Cholestyramine is a non-absorbable ion-exchange resin which specifically binds bile salts. We have treated seven patients with acute or chronic radiation-induced diarrhea that was refractory to the usual methods of control with cholestyramine. In each case, the diarrhea was controlled with cholestyramine. This observation supports previous experimental work with animals which indicated that bile salts contribute to the genesis of radiation-induced diarrhea. Cholestyramine is well-tolerated, but should not be administered with certain oral medications. The results of this small series are preliminary, but point the way toward a more extensive clinical trial to define the usefulness of cholestyramine in the treatment of refractory acute or chronic radiation-induced diarrhea

Involvement of prostaglandins and histamine in radiation-induced temperature responses in rats

International Nuclear Information System (INIS)

Kandasamy, S.B.; Hunt, W.A.

1990-01-01

Exposure of rats to 1-15 Gy of gamma radiation induced hyperthermia, whereas exposure to 20-150 Gy produced hypothermia. Since radiation exposure induced the release of prostaglandins (PGs) and histamine, the role of PGs and histamine in radiation-induced temperature changes was examined. Radiation-induced hyper- and hypothermia were antagonized by pretreatment with indomethacin, a cyclooxygenase inhibitor. Intracerebroventricular administration of PGE2 and PGD2 induced hyper- and hypothermia, respectively. Administration of SC-19220, a specific PGE2 antagonist, attenuated PGE2- and radiation-induced hyperthermia, but it did not antagonize PGD2- or radiation-induced hypothermia. Consistent with an apparent role of histamine in hypothermia, administration of disodium cromoglycate (a mast cell stabilizer), mepyramine (H1-receptor antagonist), or cimetidine (H2-receptor antagonist) attenuated PGD2- and radiation-induced hypothermia. These results suggest that radiation-induced hyperthermia is mediated via PGE2 and that radiation-induced hypothermia is mediated by another PG, possibly PGD2, via histamine

Molecular epidemiology of radiation-induced carcinogenesis

International Nuclear Information System (INIS)

Trosko, J.E.

1996-01-01

The role of ionizing radiation in carcinogenesis is discussed. Every cell contains proto-oncogenes, which if damaged may lead to cell transformation. Every cell also contains tumor suppressor genes, which guard against transformation. Thus, transformation would seem to require a double injury to the DNA in a cell. Ionizing radiation is known to be a relatively weak mutagen, but a good clastogen (inducer of chromosome breaks, deletions and rearrangements). Ionizing radiation may therefore be a 'promoter' of cancer, i.e. a stimulant of the clonal expansion of transformed cells, if it kills enough cells to induce compensatory hyperplasia - i.e. rapid growth of cells. Ionizing radiation may be a 'progressor', if it deactivates tumor suppressor genes tending to suppress the growth of existing clones of transformed cells resulting from any of numerous causes. It may therefore be an oversimplification to say that radiation causes cancer; rather, it seems to be a weak initiator, an indirect promoter, and a late-stage progressor. 2 figs

Radiation-induced tumors of the nervous system

International Nuclear Information System (INIS)

Bernstein, M.; Laperriere, N.

1991-01-01

Therapeutic and nontherapeutic ionizing radiation has long been recognized as a putative carcinogenic agent, but the evidence that radiation causes tumors is circumstantial at worst and statistically significant at best. There are no distinct histological, biochemical, cytogenetic, or clinical criteria that can be used to determine if an individual tumor was caused directly by previous irradiation of the anatomic area. Additional supportive evidence for radiation-induced tumors includes a position correlation between radiation dose and tumor incidence (usually in the low dose range) and experimental induction of the same neoplasm in appropriate animal models. even if these criteria are fulfilled, coincidental development of a second tumor can never be discounted in an individual patient, particularly if there is an underlying diathesis to develop multiple tumors of different histology, such as in Recklinghausen's disease, or if there is an strong family history for the development of neoplastic disease. In this paper, the authors critically evaluate the available evidence to support the hypothesis that radiation induces tumors in the nervous system. The current concepts of radiation carcinogenesis are discussed and are followed by a discussion of animal data and clinical experience in humans. Finally, a brief discussion on treatment of radiation-induced nervous system tumors is presented

Disruptions and Their Mitigation in TEXTOR

International Nuclear Information System (INIS)

Finken, K.H.; Jaspers, R.; Kraemer-Flecken, A.; Savtchkov, A.; Lehnen, M.; Waidmann, G.

2005-01-01

Disruptions remain a major concern for tokamak devices, particularly for large machines. The critical issues are the induced (halo) currents and the resulting forces, the excessive heating of exposed surfaces by the instantaneous power release, and the possible occurrence of highly energetic runaway electrons. The key topics of the investigations on TEXTOR in the recent years concerned (a) the power deposition pattern recorded by a fast infrared scanner, (b) the runaway generation measured by synchrotron radiation in the infrared spectral region, (c) method development for 'healing' discharges that are going to disrupt, and (d) massive gas puffing for mitigating the adverse effects of disruptions

Characterization of radiation-induced Apoptosis in rodent cell lines

International Nuclear Information System (INIS)

Guo, Min; Chen, Changhu; Ling, C.C.

1997-01-01

For REC:myc(ch1), Rat1 and Rat1:myc b cells, we determined the events in the development of radiation-induced apoptosis to be in the following order: cell division followed by chromatin condensation, membrane blebbing, loss of adhesion and the uptake of vital dye. Experimental data which were obtained using 4 He ions of well defined energies and which compared the dependence of apoptosis and clonogenic survival on 4 He range strongly suggested that in our cells both apoptosis and loss of clonogenic survival resulted from radiation damage to the cell nucleus. Corroboratory evidence was that BrdU incorporation sensitized these cells to radiation-induced apoptosis. Comparing the dose response for apoptosis and the clonogenic survival curves for Rat1 and Rat1:myc b cells, we concluded that radiation-induced cell inactivation as assayed by clonogenic survival, and that a modified linear-quadratic model, proposed previously, modeled such a contribution effectively. In the same context, the selective increase in radiation-induced apoptosis. Comparing the dose response for apoptosis and the clonogenic survival curves for Rat1 and Rat1:myc b cells, we concluded that radiation-induced apoptosis contributed to the overall radiation-induced cell inactivation as assayed by clonogenic survival, and that a modified linear-quadratic model, proposed previously, modeled such a contribution effectively. In the same context, the selective increase in radiation-induced apoptosis during late S and G 2 phases reduced the relative radioresistance observed for clonogenic survival during late S and G 2 phases. 30 refs., 8 figs

Application of Nano PAC on Mitigating Membrane Fouling by Surface Properties Optimization

Directory of Open Access Journals (Sweden)

Mi Hairong

2016-01-01

Full Text Available Membrane material has been widely accepted owing to the ability in water treatment, but the membrane fouling problem in using process is seriously restricted the promotion of membrane technology. So in this research nano PAC flocculant is added into the raw water to reach the goals of strengthening treatment efficiency and mitigating membrane fouling. According to the TMP change, it results that the PAC dosage of 45mg/L can realize the purpose to mitigate membrane fouling best. Compared with MBR, the MCBR is 16 days tardiness at the change of TMP, 1/3 gel layer filtration resistance less and 3.5% C element content fewer. The sum of C, O and N elements content, in addition, in the gel layer pollutants is more than 95%. That means membrane pollution is mainly caused by organic matter and nano PAC has the effect on surface properties optimization and membrane fouling mitigating.

Melatonin mitigates neomycin-induced hair cell injury in zebrafish.

Science.gov (United States)

Oh, Kyoung Ho; Rah, Yoon Chan; Hwang, Kyu Ho; Lee, Seung Hoon; Kwon, Soon Young; Cha, Jae Hyung; Choi, June

2017-10-01

Ototoxicity due to medications, such as aminoglycosides, is irreversible, and free radicals in the inner ear are assumed to play a major role. Because melatonin has an antioxidant property, we hypothesize that it might mitigate hair cell injury by aminoglycosides. The objective of this study was to evaluate whether melatonin has an alleviative effect on neomycin-induced hair cell injury in zebrafish (Danio rerio). Various concentrations of melatonin were administered to 5-day post-fertilization zebrafish treated with 125 μM neomycin for 1 h. Surviving hair cells within four neuromasts were compared with that of a control group. Apoptosis was assessed via terminal deoxynucleotidyl transferase dUTP nick-end labeling assay. The changes of ultrastructure were confirmed using a scanning electron microscope. Melatonin alleviated neomycin-induced hair cell injury in neuromasts (neomycin + melatonin 100 μM: 13.88 ± 0.91 cells, neomycin only: 7.85 ± 0.90 cells; n = 10, p melatonin for 1 h in SEM findings. Melatonin is effective in alleviating aminoglycoside-induced hair cell injury in zebrafish. The results of this study demonstrated that melatonin has the potential to reduce apoptosis induced by aminoglycosides in zebrafish.

Interaction of alpha radiation with thermally-induced defects in silicon

International Nuclear Information System (INIS)

Ali, Akbar; Majid, Abdul

2008-01-01

The interaction of radiation-induced defects created by energetic alpha particles and thermally-induced defects in silicon has been studied using a Deep Level Transient Spectroscopy (DLTS) technique. Two thermally-induced defects at energy positions E c -0.48 eV and E c -0.25 eV and three radiation-induced defects E2, E3 and E5 have been observed. The concentration of both of the thermally-induced defects has been observed to increase on irradiation. It has been noted that production rates of the radiation-induced defects are suppressed in the presence of thermally-induced defects. A significant difference in annealing characteristics of thermally-induced defects in the presence of radiation-induced defects has been observed compared to the characteristics measured in pre-irradiated samples

The Small Mixed Field Autonomous Radiation Tracker (SMART) Dosimeter, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Active dosimeters for astronauts and space weather monitors are critical tools for mitigating radiation induced health issues or system failure on capital equipment....

MSBIS: A Multi-Step Biomedical Informatics Screening Approach for Identifying Medications that Mitigate the Risks of Metoclopramide-Induced Tardive Dyskinesia

Directory of Open Access Journals (Sweden)

Dong Xu

2017-12-01

Full Text Available In 2009 the U.S. Food and Drug Administration (FDA placed a black box warning on metoclopramide (MCP due to the increased risks and prevalence of tardive dyskinesia (TD. In this study, we developed a multi-step biomedical informatics screening (MSBIS approach leveraging publicly available bioactivity and drug safety data to identify concomitant drugs that mitigate the risks of MCP-induced TD. MSBIS includes (1 TargetSearch (http://dxulab.org/software bioinformatics scoring for drug anticholinergic activity using CHEMBL bioactivity data; (2 unadjusted odds ratio (UOR scoring for indications of TD-mitigating effects using the FDA Adverse Event Reporting System (FAERS; (3 adjusted odds ratio (AOR re-scoring by removing the effect of cofounding factors (age, gender, reporting year; (4 logistic regression (LR coefficient scoring for confirming the best TD-mitigating drug candidates. Drugs with increasing TD protective potential and statistical significance were obtained at each screening step. Fentanyl is identified as the most promising drug against MCP-induced TD (coefficient: −2.68; p-value < 0.01. The discovery is supported by clinical reports that patients fully recovered from MCP-induced TD after fentanyl-induced general anesthesia. Loperamide is identified as a potent mitigating drug against a broader range of drug-induced movement disorders through pharmacokinetic modifications. Using drug-induced TD as an example, we demonstrated that MSBIS is an efficient in silico tool for unknown drug-drug interaction detection, drug repurposing, and combination therapy design.

Radiation-induced damage of membranes

International Nuclear Information System (INIS)

Yonei, Shuji

1977-01-01

An outline of membranous structure was stated, and radiation-induced damage of membranes were surveyed. By irradiation, permeability of membranes, especially passive transportation mechanism, was damaged, and glycoprotein in the surface layers of cells and the surface layer structures were changed. The intramembranous damage was induced by decrease of electrophoresis of nuclear mambranes and a quantitative change of cytochrome P450 of microsomal membranes of the liver, and peroxidation of membranous lipid and SH substitute damage of membranous protein were mentioned as the mechanism of membranous damage. Recovery of membranous damage depends on radiation dose and temperature, and membranous damage participates largely in proliferation death. (tsunoda, M.)

Protection against radiation-induced performance decrement in mice

International Nuclear Information System (INIS)

Mukherjee, S.K.; Pant, Kanchan; Goel, H.C.; Jain, Viney

1997-01-01

Recognizing that there is lack of information on the effects of low-level ionizing radiations and the modifying role of radioprotectors, an attempt has been made in this study to explore the relationship between impairment of spatial learning and low level of radiation exposure. A radial arm maze was utilised to evaluate radiation-induced behavioural alterations and performance decrement in mice. Immediately after whole body exposure to gamma radiation (absorbed dose, 1 Gy) significant perturbations in the learned behaviour of the animals were observed. The regular control movement became irregular and the food consumption time was reduced appreciably (40%). Recovery took place in four days. If diltiazem (7 mg/kg b.w.), a Ca 2+ channel blocker and a radioprotector, was administered i.p. 20-30 min prior to irradiation, radiation-induced behavioural abnormalities were reduced. Mechanisms underlying protection by diltiazem against radiation-induced performance decrement observed in the present study need to be investigated. (author). 23 refs., 2 figs

Radiation-Induced Second Cancer Risk Estimates From Radionuclide Therapy

Science.gov (United States)

Bednarz, Bryan; Besemer, Abigail

2017-09-01

The use of radionuclide therapy in the clinical setting is expected to increase significantly over the next decade. There is an important need to understand the radiation-induced second cancer risk associated with these procedures. In this study the radiation-induced cancer risk in five radionuclide therapy patients was investigated. These patients underwent serial SPECT imaging scans following injection as part of a clinical trial testing the efficacy of a 131Iodine-labeled radiopharmaceutical. Using these datasets the committed absorbed doses to multiple sensitive structures were calculated using RAPID, which is a novel Monte Carlo-based 3D dosimetry platform developed for personalized dosimetry. The excess relative risk (ERR) for radiation-induced cancer in these structures was then derived from these dose estimates following the recommendations set forth in the BEIR VII report. The radiation-induced leukemia ERR was highest among all sites considered reaching a maximum value of approximately 4.5. The radiation-induced cancer risk in the kidneys, liver and spleen ranged between 0.3 and 1.3. The lifetime attributable risks (LARs) were also calculated, which ranged from 30 to 1700 cancers per 100,000 persons and were highest for leukemia and the liver for both males and females followed by radiation-induced spleen and kidney cancer. The risks associated with radionuclide therapy are similar to the risk associated with external beam radiation therapy.

Thixotropic gel-like composition and sterile blood-collecting and separating device

International Nuclear Information System (INIS)

Semersky, F.E.

1980-01-01

A thixotropic gel-like composition comprising liquid polybutadiene and an inorganic inert filler dispersed therein is adapted for use as a sealing barrier between separated phases of differing densities of a fluid in which said composition has at rest a density intermediate said differing densities, said gel-like composition being substantially resistant to sterilizing radiation. There is also disclosed a pre-packaged blood collecting and separating device which contains a mixture of liquid polybutadiene and an inorganic, inert filler, such as silica, as a thixotropic gel adapted at rest to form a sealing barrier between separated blood phases. The device and gel are subjected to sterilizing radiation to form a substantially sterile device, substantially free of backflow contamination without degradation of the physical properties of the gel. (author)

Space debris mitigation - engineering strategies

Science.gov (United States)

Taylor, E.; Hammond, M.

The problem of space debris pollution is acknowledged to be of growing concern by space agencies, leading to recent activities in the field of space debris mitigation. A review of the current (and near-future) mitigation guidelines, handbooks, standards and licensing procedures has identified a number of areas where further work is required. In order for space debris mitigation to be implemented in spacecraft manufacture and operation, the authors suggest that debris-related criteria need to become design parameters (following the same process as applied to reliability and radiation). To meet these parameters, spacecraft manufacturers and operators will need processes (supported by design tools and databases and implementation standards). A particular aspect of debris mitigation, as compared with conventional requirements (e.g. radiation and reliability) is the current and near-future national and international regulatory framework and associated liability aspects. A framework for these implementation standards is presented, in addition to results of in-house research and development on design tools and databases (including collision avoidance in GTO and SSTO and evaluation of failure criteria on composite and aluminium structures).

Directed shift of vaginal microbiota induced by vaginal application of sucrose gel in rhesus macaques.

Science.gov (United States)

Hu, Kai-tao; Zheng, Jin-xin; Yu, Zhi-jian; Chen, Zhong; Cheng, Hang; Pan, Wei-guang; Yang, Wei-zhi; Wang, Hong-yan; Deng, Qi-wen; Zeng, Zhong-ming

2015-04-01

Sucrose gel was used to treat bacterial vaginosis in a phase III clinical trial. However, the changes of vaginal flora after treatment were only examined by Nugent score in that clinical trial, While the vaginal microbiota of rhesus macaques is characterized by anaerobic, Gram-negative bacteria, few lactobacilli, and pH levels above 4.6, similar to the microbiota of patients with bacterial vaginosis. This study is aimed to investigate the change of the vaginal microbiota of rehsus macaques after topical use of sucrose gel to reveal more precisely the bacterial population shift after the topical application of sucrose gel. Sixteen rhesus macaques were treated with 0.5 g sucrose gel vaginally and three with 0.5 g of placebo gel. Vaginal swabs were collected daily following treatment. Vaginal pH levels and Nugent scores were recorded. The composition of the vaginal micotbiota was tested by V3∼V4 16S rDNA metagenomic sequencing. Dynamic changes in the Lactobacillus genus were analyzed by qPCR. The vaginal microbiota of rhesus macaques are dominated by anaerobic Gram-negative bacteria, with few lactobacilli and high pH levels above 4.6. After five days' treatment with topical sucrose gel, the component percentage of Lactobacillus in vaginal microbiota increased from 1.31% to 81.59%, while the component percentage of Porphyromonas decreased from 18.60% to 0.43%, Sneathia decreased from 15.09% to 0.89%, Mobiluncus decreased from 8.23% to 0.12%, etc.. The average vaginal pH values of 16 rhesus macaques of the sucrose gel group decreased from 5.4 to 3.89. There were no significant changes in microbiota and vaginal pH observed in the placebo group. Rhesus macaques can be used as animal models of bacterial vaginosis to develop drugs and test treatment efficacy. Furthermore, the topical application of sucrose gel induced the shifting of vaginal flora of rhesus macaques from a BV kind of flora to a lactobacilli-dominating flora. Copyright © 2015 The Authors. Published by

Localization of quantitative trait loci associated with radiation induced pulmonary fibrosis in the mouse

International Nuclear Information System (INIS)

Oas, L.G.; Haston, C.K.; Travis, E.L.

1997-01-01

Purpose/Objective: Pulmonary fibrosis is often a limiting factor in the planning of radiotherapy for thoracic neoplasms. Differences in the propensity to develop radiation induced pulmonary fibrosis have been noted between C3Hf/Kam (resistant) and C57BL/6J (susceptible) mouse strains. Bleomycin and radiation induced pulmonary fibrosis have been shown to be heritable traits in mice with significant linkage to the major histocompatibility complex on chromosome 17. The heritability of radiation induced damage was estimated to be 38%±11% with 1-2 genetic factors influencing expression. Only 6.6% of the phenotypic variance could be attributed to chromosome 17. A search of the genome was undertaken to identify loci which may be responsible for the remaining phenotypic variance. Materials and Methods: C3Hf/Kam and C57BL/6J mice were crosbred to yield F1 and F2 (F1 intercross) generations. Two hundred sixty eight males and females of the F2 generation were treated with orthovoltage radiation, 14 or 16 Gy, to the whole thorax. The mice were sacrificed after development of respiratory distress or at 33 weeks. Histologic sections were assessed with quantified image analysis to determine the percentage of fibrosis in both lungs. Genotyping was done on the pooled DNA of the mice who developed respiratory distress with 44 32 P labeled microsatellite markers having an average spacing of 24.5 cM. Correlation of the quantitative trait loci (QTLs) with the highest quartile of fibrosis revealed 10 out of 44 regions showing possible linkage. Individual DNA from 54 mice with the least fibrosis and 40 with the most fibrosis were probed using these markers. PCR and gel electrophoresis were performed and the results analysed. Results: Of the 10 markers analysed, one locus on chromosome 1 meets the criterion of suggestion of linkage. Conclusion: These findings point to regions on the mouse genome for which further investigation of fibrosis associated loci may be warranted

Radiation induced changes in the airway - anaesthetic implications ...

African Journals Online (AJOL)

Radiation induced changes in the airway - anaesthetic implications: case report. Mallika Balakrishnan, Renju Kuriakose, Rachel Cherian Koshy. Abstract. Radiation induces a variety of changes in the airway that can potentially lead to difficult intubation. Osteoradionecrosis (ORN) of the mandible, a severe consequence of ...

Radiation-induced changes in DNA methylation of repetitive elements in the mouse heart

Energy Technology Data Exchange (ETDEWEB)

Koturbash, Igor, E-mail: ikoturbash@uams.edu [Department of Environmental and Occupational Health, University of Arkansas for Medical Sciences, Little Rock, AR 72205 (United States); Miousse, Isabelle R. [Department of Environmental and Occupational Health, University of Arkansas for Medical Sciences, Little Rock, AR 72205 (United States); Sridharan, Vijayalakshmi [Division of Radiation Health, Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205 (United States); Nzabarushimana, Etienne; Skinner, Charles M. [Department of Environmental and Occupational Health, University of Arkansas for Medical Sciences, Little Rock, AR 72205 (United States); Melnyk, Stepan B.; Pavliv, Oleksandra [Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR 72205 (United States); Hauer-Jensen, Martin [Division of Radiation Health, Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205 (United States); Surgical Service, Central Arkansas Veterans Healthcare System, Little Rock, AR 72205 (United States); Nelson, Gregory A. [Departments of Basic Sciences and Radiation Medicine, Loma Linda University, Loma Linda, CA 92354 (United States); Boerma, Marjan [Division of Radiation Health, Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205 (United States)

2016-05-15

Highlights: • Radiation-induced dynamic changes in cardiac DNA methylation were detected. • Early LINE-1 hypomethylation was followed by hypermethylation at a later time-point. • Radiation affected one-carbon metabolism in the heart tissue. • Irradiation resulted in accumulation of satellite DNA mRNA transcripts. - Abstract: DNA methylation is a key epigenetic mechanism, needed for proper control over the expression of genetic information and silencing of repetitive elements. Exposure to ionizing radiation, aside from its strong genotoxic potential, may also affect the methylation of DNA, within the repetitive elements, in particular. In this study, we exposed C57BL/6J male mice to low absorbed mean doses of two types of space radiation—proton (0.1 Gy, 150 MeV, dose rate 0.53 ± 0.08 Gy/min), and heavy iron ions ({sup 56}Fe) (0.5 Gy, 600 MeV/n, dose rate 0.38 ± 0.06 Gy/min). Radiation-induced changes in cardiac DNA methylation associated with repetitive elements were detected. Specifically, modest hypomethylation of retrotransposon LINE-1 was observed at day 7 after irradiation with either protons or {sup 56}Fe. This was followed by LINE-1, and other retrotransposons, ERV2 and SINE B1, as well as major satellite DNA hypermethylation at day 90 after irradiation with {sup 56}Fe. These changes in DNA methylation were accompanied by alterations in the expression of DNA methylation machinery and affected the one-carbon metabolism pathway. Furthermore, loss of transposable elements expression was detected in the cardiac tissue at the 90-day time-point, paralleled by substantial accumulation of mRNA transcripts, associated with major satellites. Given that the one-carbon metabolism pathway can be modulated by dietary modifications, these findings suggest a potential strategy for the mitigation and, possibly, prevention of the negative effects exerted by ionizing radiation on the cardiovascular system. Additionally, we show that the methylation status and

Radiation induced changes in proteome of mice jejunum: an in vivo 2DE study

International Nuclear Information System (INIS)

Bajaj, Sania; Dutta, Ajaswrata; Gupta, Manju L.

2014-01-01

Radiation exposure results in severe damage to biological system, by affecting cellular macromolecules of an individual. Damage to bio-molecules may lead to up/down-regulation of proteins, leading to dysfunction of organs. Gastrointestinal tract a key organ for digestion, absorption and barrier to the luminal bacteria and toxins, is one of the highly sensitive radiosensitive organ. Current study is focused on differential proteomic approach to understand the effect of radiation on intestinal (jejunum) proteins in a time dependent manner. Experiments were carried out initially to determine the appropriate conditions for separation of proteins in GI tissue of non irradiated control male C57BL6/J mice. 8-10 weeks old animals were exposed to 9 Gy (lethal) dose of gamma radiation. Differential expression of gastrointestinal tissue (jejunum) proteome was studied by 2DE at different time intervals. The intensity of protein spots of different treatment groups and control was measured by PD Quest software and the differential expression of respective proteins was calculated manually. Comparison of 2-DE gel images of irradiated jejunum tissue samples showed differential expression of various proteins when compared with untreated samples. A significant upregulation of total protein spots was observed within 1 hr group of 9 Gy radiation exposed sample and maximum down-regulation was evident at 72 hr. Out of 24 spots identified in the irradiated samples, 15 spots were down-regulated, and 3 spots were found missing in 72 hr group of irradiated samples respectively. Time dependent regulation of protein expression in irradiated jejunum was thus prominently evident. The data obtained from the present study has revealed differential radio sensitivity of some of the proteins which certainly have a definite role in inducing major cellular changes after radiation exposure. The finding also suggests that proteomic approach could be a potential tool to access the role of specific

Poor outcome in radiation-induced constrictive pericarditis

International Nuclear Information System (INIS)

Karram, T.; Rinkevitch, D.; Markiewicz, W.

1993-01-01

The purpose was to compare the outcome of patients with radiation-induced constrictive pericarditis versus patients with constiction due to another etiology. Twenty patients with constrictive pericarditis were seen during 1975-1986 at a single medical center. Six had radiation-induced constrictive pericarditis (Group A). The etiology was idiopathic in ten subjects and secondary to carcinomatous encasement, chronic renal failure, purulent infection and tuberculosis in one patient each (Group B, N = 14). Meang age was 53.4 ± 15.5 years. Extensive pericardiectomy was performed in 3/6 Group A and 13/14 Group B patients. All Group A patients died, 4 weeks - 11 years post-diagnosis (median = 10 months). Two Group A patients died suddenly, one died post-operatively of respiratory failure, another of pneumonia and two of recurrent carcinoma. Thirteen Group B patients are alive (median follow-up = 72 months). The only death in this group was due to metastatic cancer. The poor outcome with radiation-induced constriction is probably multi-factorial. Poor surgical outcome is to be expected in patients with evidence of recurrent tumor, high-dose irradiation, pulmonary fibrosis or associated radiation-induced myocardinal, valvular or coronary damage

Poor outcome in radiation-induced constrictive pericarditis

Energy Technology Data Exchange (ETDEWEB)

Karram, T.; Rinkevitch, D.; Markiewicz, W. (Technion Medical School, Haifa (Israel))

1993-01-15

The purpose was to compare the outcome of patients with radiation-induced constrictive pericarditis versus patients with constiction due to another etiology. Twenty patients with constrictive pericarditis were seen during 1975-1986 at a single medical center. Six had radiation-induced constrictive pericarditis (Group A). The etiology was idiopathic in ten subjects and secondary to carcinomatous encasement, chronic renal failure, purulent infection and tuberculosis in one patient each (Group B, N = 14). Meang age was 53.4 [+-] 15.5 years. Extensive pericardiectomy was performed in 3/6 Group A and 13/14 Group B patients. All Group A patients died, 4 weeks - 11 years post-diagnosis (median = 10 months). Two Group A patients died suddenly, one died post-operatively of respiratory failure, another of pneumonia and two of recurrent carcinoma. Thirteen Group B patients are alive (median follow-up = 72 months). The only death in this group was due to metastatic cancer. The poor outcome with radiation-induced constriction is probably multi-factorial. Poor surgical outcome is to be expected in patients with evidence of recurrent tumor, high-dose irradiation, pulmonary fibrosis or associated radiation-induced myocardinal, valvular or coronary damage.

Stem cell-based therapies for acute radiation syndrome

International Nuclear Information System (INIS)

Guha, Chandan

2014-01-01

Exposure to high doses of ionizing radiation in the event of accidental or intentional incident such as nuclear/radiological terrorism can lead to debilitating injuries to multiple organs resulting in death within days depending on the amount of radiation dose and the quality of radiation. Unfortunately, there is not a single FDA-licensed drug approved against acute radiation injury. The RadStem Center for Medical Countermeasures against Radiation (RadStem CMGR) program at Einstein is developing stem cell-based therapies to treat acute radiation syndrome (ARS). We have demonstrated that intravenous transplantation of bone marrow-derived and adipose-derived stromal cells, consisting of a mixture of mesenchymal, endothelial and myeloid progenitors can mitigate mice exposed to whole body irradiation of 12 Gy or whole abdominal irradiation of up to 20 Gy. We identified a variety of growth and differentiation factors that individually is unable to improve survival of animals exposed to lethal irradiation, but when administered sequentially mitigates radiation injury and improves survival. We termed this phenomenon as synthetic survival and describe a new paradigm whereby the 'synthetic survival' of irradiated tissues can be promoted by systemic administration of growth factors to amplify residual stem cell clonogens post-radiation exposure, followed by a differentiation factor that favors tissue stem cell differentiation. Synthetic survival can be applied to mitigate lethal radiation injury in multiple organs following radiation-induced hematopoeitic, gastrointestinal and pulmonary syndromes. (author)

Radiation induced pesticidal microbes

Energy Technology Data Exchange (ETDEWEB)

Kim, Ki Yup; Lee, Y. K.; Kim, J. S.; Kim, J. K.; Lee, S. J.; Lim, D. S

2001-01-01

To isolate pesticidal microbes against plant pathogenic fungi, 4 strains of bacteria(K1. K3, K4, YS1) were isolated from mushroom compost and hot spring. K4, K1, K3, YS1 strain showed wide antifungal spectrum and high antifungal activities against 12 kinds of fungi. Specific proteins and the specific transcribed genes were found from the YS1 and its radiation-induced mutants. And knock-out mutants of antifungal activity were derived by transposon mutagenesis. From these knock-out mutants, the antifungal activity related genes and its modification by gamma-ray radiation are going to be studied. These results suggested that radiation could be an useful tool for the induction of functional mutants.

Radiation induced pesticidal microbes

International Nuclear Information System (INIS)

Kim, Ki Yup; Lee, Y. K.; Kim, J. S.; Kim, J. K.; Lee, S. J.; Lim, D. S.

2001-01-01

To isolate pesticidal microbes against plant pathogenic fungi, 4 strains of bacteria(K1. K3, K4, YS1) were isolated from mushroom compost and hot spring. K4, K1, K3, YS1 strain showed wide antifungal spectrum and high antifungal activities against 12 kinds of fungi. Specific proteins and the specific transcribed genes were found from the YS1 and its radiation-induced mutants. And knock-out mutants of antifungal activity were derived by transposon mutagenesis. From these knock-out mutants, the antifungal activity related genes and its modification by gamma-ray radiation are going to be studied. These results suggested that radiation could be an useful tool for the induction of functional mutants

Diallyl sulfide as a radio-mitigator

International Nuclear Information System (INIS)

Katoch, Omika; Agrawala, Paban K.

2014-01-01

Mitigation or post irradiation radiation protection involves repair and recovery of critical organs such as the hematopoietic and gastrointestinal (GI) system besides others. The present study describes mitigating potential of diallyl sulfied (DAS), a constituent of garlic in mice hematopoietic and GI systems. 160 mg/kg body weight of DAS was administered intra-peritoneally after 2 hrs of radiation exposure. 160 mg/kg body weight of DAS administration resulted in 37% animal survival as opposed to 100% mortality in 9 Gy whole body irradiated group only. DAS also normalized the different parameters of blood in irradiated mice. This dose of DAS also decreased bone marrow apoptosis (TUNEL assay) in DAS + 5 Gy group as compared to irradiation group that resulted in increased cellularity of bone marrow as seen by Hematoxylin and Eosin in 5 um thick sections. Administration of DAS also alleviates the symptoms in GI system caused by radiation exposure. Administration of 160 mg/kg body weight of DAS in 11 Gy irradiated mice resulted in increased villi length and underlying stem cells count as compared to irradiation group only. Further experiments are needed to prove DAS as a potential radiation mitigator agent. (author)

Radiation: behavioral implications in space

International Nuclear Information System (INIS)

Bogo, V.

1988-01-01

Since future space missions are likely to be beyond Earth's protective atmosphere, a potentially significant hazard is radiation. The following behavioural situations are addressed in this paper: (1) space radiations are more effective at disrupting behaviour; (2) task demands can aggravate the radiation-disruption; (3) efforts to mitigate disruption with drugs or shielding are not satisfactory and the drugs can be behaviourally toxic; and (4) space- and radiation-induced emesis combined may be synergistic. Thus future space travel will be a demanding, exciting time for behavioral toxicologists, and while the circumstances may seem insurmountable at first, creative application of scientific expertise should illicit solutions, similar to demanding situations confronted before. (author)

Radiation polymerization and crosslinking of N-isopropylacrylamide in aqueous solution and in solid state

International Nuclear Information System (INIS)

Safranj, A.; Yoshida, Masaru; Omichi, Hideki; Nagaoka, Noriyasu; Kubota, Hitoshi; Katakai, Ryoichi.

1995-01-01

Poly(N-isopropylacrylamide) hydrogels were synthesized by radiation induced simultaneous polymerization and cross-linking. Aqueous monomer solutions and pure monomer, without crosslinker, were irradiated in nitrogen atmosphere at a 60 Co gamma source. The conversion from monomer to polymer and cross-linked gel was investigated as a function of temperature and monomer concentration. The swelling behavior of the gels showed clear dependence on the synthesis conditions. (author)

Single event and TREE latchup mitigation for a star tracker sensor: An innovative approach to system level latchup mitigation

International Nuclear Information System (INIS)

Kimbrough, J.R.; Colella, N.J.; Davis, R.W.; Bruener, D.B.; Coakley, P.G.; Lutjens, S.W.; Mallon, C.E.

1994-08-01

Electronic packages designed for spacecraft should be fault-tolerant and operate without ground control intervention through extremes in the space radiation environment. If designed for military use, the electronics must survive and function in a nuclear radiation environment. This paper presents an innovative ''blink'' approach rather than the typical ''operate through'' approach to achieve system level latchup mitigation on a prototype star tracker camera. Included are circuit designs, flash x-ray test data, and heavy ion data demonstrating latchup mitigation protecting micro-electronics from current latchup and burnout due to Single Event Latchup (SEL) and Transient Radiation Effects on Electronics (TREE)

Cataracts induced by microwave and ionizing radiation

International Nuclear Information System (INIS)

Lipman, R.M.; Tripathi, B.J.; Tripathi, R.C.

1988-01-01

Microwaves most commonly cause anterior and/or posterior subcapsular lenticular opacities in experimental animals and, as shown in epidemiologic studies and case reports, in human subjects. The formation of cataracts seems to be related directly to the power of the microwave and the duration of exposure. The mechanism of cataractogenesis includes deformation of heat-labile enzymes, such as glutathione peroxide, that ordinarily protect lens cell proteins and membrane lipids from oxidative damage. Oxidation of protein sulfhydryl groups and the formation of high-molecular-weight aggregates cause local variations in the orderly structure of the lens cells. An alternative mechanism is thermoelastic expansion through which pressure waves in the aqueous humor cause direct physical damage to the lens cells. Cataracts induced by ionizing radiation (e.g., X-rays and gamma rays) usually are observed in the posterior region of the lens, often in the form of a posterior subcapsular cataract. Increasing the dose of ionizing radiation causes increasing opacification of the lens, which appears after a decreasing latency period. Like cataract formation by microwaves, cataractogenesis induced by ionizing radiation is associated with damage to the lens cell membrane. Another possible mechanism is damage to lens cell DNA, with decreases in the production of protective enzymes and in sulfur-sulfur bond formation, and with altered protein concentrations. Until further definitive conclusions about the mechanisms of microwaves and ionizing radiation induced cataracts are reached, and alternative protective measures are found, one can only recommend mechanical shielding from these radiations to minimize the possibility of development of radiation-induced cataracts. 74 references

Development of hydroxyapatite-chitosan gel sunscreen combating clinical multidrug-resistant bacteria

Science.gov (United States)

Morsy, Reda; Ali, Sameh S.; El-Shetehy, Mohamed

2017-09-01

The several harmful effects on infected human skin resulting from exposure to the sun's UV radiation generate an interest in the development of a multifunctional hydroxyapatite-chitosan (HAp-chitosan) gel that works as an antibacterial sunscreen agent for skin care. In this work, HAp-chitosan gel was synthesized via coprecipitation method by dissolving chitosan in phosphoric acid and adding HAp. The characteristics of HAp-chitosan composite were investigated by conventional techniques, such as XRD, FTIR, and SEM techniques, while its sunscreen property was investigated by UV-spectroscopy. In addition to the influence of the gel on bacterial cell morphology, the antibacterial activity of HAp-chitosan gel against clinical multidrug resistant skin pathogens, such as Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa has been studied. The results revealed the formation of HAp-chitosan gel having nanosized particles, which confers protection against UV-radiation. The antibacterial activity records showed that chitosan-HAp gel exhibits a significant effect on the growth and ultrastructure of multi-drug resistant bacterial activities. Therefore, the chitosan-HAp gel is promising for skin health care as an antibacterial sunscreen.

Prevention of radiation induced xerostomia and improved quality of life: Submandibular salivary gland transfer

International Nuclear Information System (INIS)

Heck, K.

2003-01-01

Over 60,000 new cases of head and neck cancers, and approximately 15,000 deaths occur every year in the United States (1). Head and neck cancers affect more men then women by a factor of 2:1, although the incidence of women is increasing as a result of increased tobacco use (2). Over 90% of all head and neck cancers are squamous cell carcinomas; most of the remaining cancers are adenocarcinomas. A combination of radiation therapy and surgery is used as the standard, primary treatment modality. Xerostomia occurs when the salivary glands are affected by irradiation. Patients experiencing xerostomia are at an increased risk for a wide variety of oral problems; all adversely affecting one's quality of life. Currently patients make lifestyle changes, dietary modifications, and use artificial salivas, sprays, gels, and lozenges to help mask their xerostomia. However, none of these products stimulate natural salivary production and act as a replacement therapy rather then a cure for xerostomia. A new protocol, RTOG 1083 has been approved by the Radiation Therapy Oncology Group, which involves a surgical transfer of a submandibular salivary gland to the submental space (where it can be easily shielded) as a method of prevention of radiation induced xerostomia. (author)

Aloe vera gel improves behavioral deficits and oxidative status in streptozotocin-induced diabetic rats.

Science.gov (United States)

Tabatabaei, Seyed Reza Fatemi; Ghaderi, Shahab; Bahrami-Tapehebur, Mohammad; Farbood, Yaghoob; Rashno, Masome

2017-12-01

Oxidative stress has a major role in progression of diabetes-related behavioral deficits. It has been suggested that Aloe vera has anti-diabetic, antioxidative, and neuroprotective effects. The present study was designed to determine the effects of Aloe vera gel on behavioral functions, oxidative status, and neuronal viability in the hippocampus of streptozotocin (STZ)-induced diabetic rats. Fifty five adult male Wistar rats were randomly divided into five groups, including: control (normal saline 8ml/kg/day; P.O.), diabetic (normal saline 8ml/kg/day; P.O.), Aloe vera gel (100mg/kg/day; P.O.), diabetic+Aloe vera gel (100mg/kg/day; P.O.) and diabetic+NPH insulin (10 IU/kg/day; S.C.). All treatments were started immediately following confirmation of diabetes in diabetic groups and were continued for eight weeks. Behavioral functions were evaluated by employing standard behavioral paradigms. Additionally, oxidative status and neuronal viability were assessed in the hippocampus. The results of behavioral tests showed that diabetes enhanced anxiety/depression-like behaviors, reduced exploratory and locomotor activities, decreased memory performance, and increased stress related behaviors. These changes in diabetic rats were accompanied by increasing oxidative stress and neuronal loss in the hippocampus. Interestingly, eight weeks of treatment with Aloe vera gel not only alleviated all the mentioned deficits related to diabetes, but in some aspects, it was even more effective than insulin. In conclusion, the results suggest that both interrelated hypoglycemic and antioxidative properties of Aloe vera gel are possible mechanisms that improve behavioral deficits and protect hippocampal neurons in diabetic animals. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

MSBIS: A Multi-Step Biomedical Informatics Screening Approach for Identifying Medications that Mitigate the Risks of Metoclopramide-Induced Tardive Dyskinesia.

Science.gov (United States)

Xu, Dong; Ham, Alexandrea G; Tivis, Rickey D; Caylor, Matthew L; Tao, Aoxiang; Flynn, Steve T; Economen, Peter J; Dang, Hung K; Johnson, Royal W; Culbertson, Vaughn L

2017-12-01

In 2009 the U.S. Food and Drug Administration (FDA) placed a black box warning on metoclopramide (MCP) due to the increased risks and prevalence of tardive dyskinesia (TD). In this study, we developed a multi-step biomedical informatics screening (MSBIS) approach leveraging publicly available bioactivity and drug safety data to identify concomitant drugs that mitigate the risks of MCP-induced TD. MSBIS includes (1) TargetSearch (http://dxulab.org/software) bioinformatics scoring for drug anticholinergic activity using CHEMBL bioactivity data; (2) unadjusted odds ratio (UOR) scoring for indications of TD-mitigating effects using the FDA Adverse Event Reporting System (FAERS); (3) adjusted odds ratio (AOR) re-scoring by removing the effect of cofounding factors (age, gender, reporting year); (4) logistic regression (LR) coefficient scoring for confirming the best TD-mitigating drug candidates. Drugs with increasing TD protective potential and statistical significance were obtained at each screening step. Fentanyl is identified as the most promising drug against MCP-induced TD (coefficient: -2.68; p-valueTD after fentanyl-induced general anesthesia. Loperamide is identified as a potent mitigating drug against a broader range of drug-induced movement disorders through pharmacokinetic modifications. Using drug-induced TD as an example, we demonstrated that MSBIS is an efficient in silico tool for unknown drug-drug interaction detection, drug repurposing, and combination therapy design. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Peculiarities of radiation induced craniopharyngioma

Energy Technology Data Exchange (ETDEWEB)

Sataev, N.M. (Uzbekskij Nauchno-Issledovatel' skij Inst. Onkologii i Radiologii, Tashkent (USSR))

1982-03-01

Due to intracranial implantation of a radiosource in rabbit brain craniopharyngioma appeared. Its specific feature is grandular differentiation of embryonal epithelium of residuals of hypophysical (craniopharyngial) passage and the presence of focuses of blood vessel tumor degeneration of hemangioma type in its stroma. It is suggested that radiation craniopharyngioma is developed along the way of epigenetic changes of cellular elements of embryonal epithelium induced by radiation.

Peculiarities of radiation induced craniopharyngioma

International Nuclear Information System (INIS)

Sataev, N.M.

1982-01-01

Due to intracranial implantation of a radiosource in rabbit brain craniopharyngioma appeared. Its specific feature is grandular differentiation of embryonal epithelium of residuals of hypophysical (craniopharyngial) passage and the presence of focuses of blood vessel tumor degeneration of hemangioma type in its stroma. It is suggested that radiation craniopharyngioma is developed along the way of epigenetic changes of cellular elements of embryonal epithelium induced by radiation

ANALYSIS AND MITIGATION OF X-RAY HAZARD GENERATED FROM HIGH INTENSITY LASER-TARGET INTERACTIONS

Energy Technology Data Exchange (ETDEWEB)

Qiu, R.; Liu, J.C.; Prinz, A.A.; Rokni, S.H.; Woods, M.; Xia, Z.; /SLAC

2011-03-21

Interaction of a high intensity laser with matter may generate an ionizing radiation hazard. Very limited studies have been made, however, on the laser-induced radiation protection issue. This work reviews available literature on the physics and characteristics of laser-induced X-ray hazards. Important aspects include the laser-to-electron energy conversion efficiency, electron angular distribution, electron energy spectrum and effective temperature, and bremsstrahlung production of X-rays in the target. The possible X-ray dose rates for several femtosecond Ti:sapphire laser systems used at SLAC, including the short pulse laser system for the Matter in Extreme Conditions Instrument (peak power 4 TW and peak intensity 2.4 x 10{sup 18} W/cm{sup 2}) were analysed. A graded approach to mitigate the laser-induced X-ray hazard with a combination of engineered and administrative controls is also proposed.

Radiation damage to histones

International Nuclear Information System (INIS)

Mee, L.K.; Adelstein, S.J.

1985-01-01

The damage to histones irradiated in isolation is being elaborated to aid the identification of the crosslinking sites in radiation-induced DNA-histone adducts. Histones are being examined by amino acid analysis to determine the destruction of residues and by polyacrylamide gel electrophoresis to delineate changes in conformation. For the slightly lysine-rich histone, H2A, a specific attack on selective residues has been established, the aromatic residues, tyrosine and phenylalanine, and the heterocyclic residue, histidine, being significantly destroyed. In addition, a significant increase in aspartic acid was found; this may represent a radiation product from scission of the ring in the histidine residues. The similarity of the effects on residues in nitrous oxide-saturated and nitrogen-saturated solutions suggests that OH . and e/sub aq//sup -/ are equally efficient and selective in their attack. On gel electrophoresis degradation of the histone H2A was found to be greatest for irradiations in nitrous oxide-saturated solutions, suggesting CH . is the most effective radical for producing changes in conformation; O/sub 2//sup -/ was essentially ineffective. Other histones are being examined for changes in amino acid composition, conformation, and for the formation of radiation products

Influence of DNA conformation on radiation-induced single-strand breaks

International Nuclear Information System (INIS)

Barone, F.; Belli, M.; Mazzei, F.

1994-01-01

We performed experiments on two DNA fragments of about 300 bp having different conformation to test whether radiation-induced single-strand breakage is dependent on DNA conformation. Breakage analysis was carried out by denaturing polyacrylamide gel electrophoresis, which allows determination of the broken site at single nucleotide resolution. We found uniform cutting patterns in B-form regions. On the contrary, X- or γ-irradiation of curved fragments of kinetoplast DNA showed that the distribution of single-strand breaks was not uniform along the fragment, as the cleavage pattern was modulated in phase with the runs of A-T pairs. This modulation likely reflected the reduced accessibility of the sites which on hydroxyl-radical attack give rise to strand breaks. The cleavage pattern was phased with the runs of A-T pairs. Moreover, the overall yield of strand breaks was considerably lower in curved DNA fragments than in those with extended straight regions. The conformation effect found here indicates that the cleavage pattern reflects the fine structural features of DNA. (orig./MG)

The impact of locally multiply damaged sites (LMDS) induced by ionizing radiation in mammalian cells

International Nuclear Information System (INIS)

Averbeck, D.; Boucher, D.

2006-01-01

Monte Carlo calculations have shown that ionising radiations produce a specific type of clustered cell damage called locally multiply damaged sites or LMDS. These lesions consist of closely positioned single-strand breaks, (oxidative) base damage and DNA double-strand breaks (DSB) in between one helical turn of DNA. As specific markers of radiation-induced damage these lesions are likely to condition biological responses and are thus of great interest for radiation protection. Calculations indicate that there should be more LMDS induced by high than by low LET radiation, and they should be absent in un-irradiated cells. Processes like K-shell activation and local Auger electron emission can be expected to add complex DSB or LMDS, producing significant chromosomal damage. In the discussion of the specificity of ionising radiation in comparison to other genotoxic agents, many arguments have been put forward that these lesions should be particularly deleterious for living cells. Complex lesions of that type should represent big obstacles for DNA repair and give rise to high lethality. Moreover, cellular attempts to repair them could accentuate harm, leading to mutations, genetic instability and cancer. In vitro experiments with oligonucleotides containing an artificially introduced set of base damage and SSB in different combinations have shown that depending on the close positioning of the damage on DNA, repair enzymes, and even whole cell extracts, are unable to repair properly and may stimulate mis-repair. Pulsed field gel electrophoresis (PFGE) in conjunction with enzymatic treatments has been used to detect LMDS in mammalian cells after high and low LET radiation. In order to further define the importance of LMDS for radiation induced cellular responses, we studied the induction of LMDS as a function of radiation dose and dose rate in mammalian cells (CHO and MRC5) using 137 Cs gamma-radiation. Using PFGE and specific glycosylases to convert oxidative damage into

The impact of locally multiply damaged sites (LMDS) induced by ionizing radiation in mammalian cells

Energy Technology Data Exchange (ETDEWEB)

Averbeck, D.; Boucher, D. [Institut Curie-Section de Recherche, UMR2027 CNRS, LCR-V28 du CEA, Centre Universitaire, 91405 Orsay Cedex (France)

2006-07-01

Monte Carlo calculations have shown that ionising radiations produce a specific type of clustered cell damage called locally multiply damaged sites or LMDS. These lesions consist of closely positioned single-strand breaks, (oxidative) base damage and DNA double-strand breaks (DSB) in between one helical turn of DNA. As specific markers of radiation-induced damage these lesions are likely to condition biological responses and are thus of great interest for radiation protection. Calculations indicate that there should be more LMDS induced by high than by low LET radiation, and they should be absent in un-irradiated cells. Processes like K-shell activation and local Auger electron emission can be expected to add complex DSB or LMDS, producing significant chromosomal damage. In the discussion of the specificity of ionising radiation in comparison to other genotoxic agents, many arguments have been put forward that these lesions should be particularly deleterious for living cells. Complex lesions of that type should represent big obstacles for DNA repair and give rise to high lethality. Moreover, cellular attempts to repair them could accentuate harm, leading to mutations, genetic instability and cancer. In vitro experiments with oligonucleotides containing an artificially introduced set of base damage and SSB in different combinations have shown that depending on the close positioning of the damage on DNA, repair enzymes, and even whole cell extracts, are unable to repair properly and may stimulate mis-repair. Pulsed field gel electrophoresis (PFGE) in conjunction with enzymatic treatments has been used to detect LMDS in mammalian cells after high and low LET radiation. In order to further define the importance of LMDS for radiation induced cellular responses, we studied the induction of LMDS as a function of radiation dose and dose rate in mammalian cells (CHO and MRC5) using {sup 137}Cs gamma-radiation. Using PFGE and specific glycosylases to convert oxidative damage

Radiation and desiccation response motif mediates radiation induced gene expression in D. radiodurans

International Nuclear Information System (INIS)

Anaganti, Narasimha; Basu, Bhakti; Apte, Shree Kumar

2015-01-01

Deinococcus radiodurans is an extremophile that withstands lethal doses of several DNA damaging agents such as gamma irradiation, UV rays, desiccation and chemical mutagens. The organism responds to DNA damage by inducing expression of several DNA repair genes. At least 25 radiation inducible gene promoters harbour a 17 bp palindromic sequence known as radiation and desiccation response motif (RDRM) implicated in gamma radiation inducible gene expression. However, mechanistic details of gamma radiation-responsive up-regulation in gene expression remain enigmatic. The promoters of highly radiation induced genes ddrB (DR0070), gyrB (DR0906), gyrA (DR1913), a hypothetical gene (DR1143) and recA (DR2338) from D. radiodurans were cloned in a green fluorescence protein (GFP)-based promoter probe shuttle vector pKG and their promoter activity was assessed in both E. coli as well as in D. radiodurans. The gyrA, gyrB and DR1143 gene promoters were active in E. coli although ddrB and recA promoters showed very weak activity. In D. radiodurans, all the five promoters were induced several fold following 6 kGy gamma irradiation. Highest induction was observed for ddrB promoter (25 fold), followed by DR1143 promoter (15 fold). The induction in the activity of gyrB, gyrA and recA promoters was 5, 3 and 2 fold, respectively. To assess the role of RDRM, the 17 bp palindromic sequence was deleted from these promoters. The promoters devoid of RDRM sequence displayed increase in the basal expression activity, but the radiation-responsive induction in promoter activity was completely lost. The substitution of two conserved bases of RDRM sequence yielded decreased radiation induction of PDR0070 promoter. Deletion of 5 bases from 5'-end of PDR0070 RDRM increased basal promoter activity, but radiation induction was completely abolished. Replacement of RDRM with non specific sequence of PDR0070 resulted in loss of basal expression and radiation induction. The results demonstrate that

Effectiveness of Melatonin, as a Radiation Damage-Mitigating Drug in Modulating Liver Biochemical disorders in γ-Irradiated Rats

International Nuclear Information System (INIS)

El-Fatih, N.M.; Elshamy, E.

2011-01-01

mitigating effects against gamma- radiation induced oxidative stress and liver injury.

Use of a ring chromosome and pulsed-field gels to study recombinational repair

International Nuclear Information System (INIS)

Game, J.C.; Arabi, S.; Mortimer, R.K.

1989-01-01

In wild type yeast, it is known that x-ray induced DNA double-strand breaks (dsb) are repaired, leading to recovery of high molecular-weight molecules on gradients or pulsed-field gels. There is genetic evidence that some or all of this repair occurs via recombinational mechanisms involving sister-chromatid exchange (SCE) and (in diploids) inter-homologue recombination. However, this evidence is indirect and qualitative. The authors of this paper are attempting to use pulsed-field gels to detect and measure recombinational repair at the physical level in yeast strains with a circular homologue of Chr. III. The authors have previously used such strains to study meiotic recombination. The authors have shown that double-size circular molecules can be detected in log-phase haploid yeast cells carrying a ring chromosome, when such cells are exposed to x-rays and allowed time for subsequent repair. Large circular molecules will not enter our pulsed-field gels, but treatment of the DNA samples with radiation prior to running the gels will linearize a fraction of such molecules with a single dsb. Such linearized molecules will run as a band whose position indicates the size of the original unbroken circles

A correlation of long term effects and radiation quality in the progeny of bystander cells after microbeam radiations: The experimental study of radiotherapy for cancer risk mitigation

Science.gov (United States)

Autsavapromporn, N.; Konishi, T.; Liu, C.; Plante, I.; Funayama, T.; Usami, N.; Azzam, EI; Suzuki, M.

2017-06-01

The goal of this study is to investigate the role of radiation quality and gap junction intercellular communication (GJIC) in the propagation of delayed stressful effects in the progeny of bystander human skin fibroblasts cultures (NB1RGB). Briefly, confluent NB1RGB cells in the presence and absence of gap junction inhibitor (AGA) were exposed to ionizing radiation (IR) with a different linear energy transfer (LET) either 5.35 keV X rays (LET ∼6 keV/μm) or 18.3 MeV/u carbon (LET ∼103 keV/μm) microbeam radiations. Following 20 populations post-irradiation, the progeny of bystander NB1RGB cells were harvested and assayed for several of biological endpoints. Our results showed that expression of stressful effects in the progeny of bystander cells is dependent on LET. The progeny of bystander cells exposed to low-LET X rays showed the persistence of oxidative stress and it was correlated with the increased mutant fraction. Such effect were not observed after high-LET carbon ions. Interestingly, inhibition of GJIC mitigated the toxic effects in the progeny of bystander cells. Together, the results contribute to the understanding of the fundamental radiation biology relating to the high-LET carbon ions to mitigate cancer risk after radiotherapy. Furthermore, GJIC be considered as a critical mediator in the bystander mutagenic effect.

The potential benefits of nicaraven to protect against radiation-induced injury in hematopoietic stem/progenitor cells with relative low dose exposures

International Nuclear Information System (INIS)

Ali, Haytham; Galal, Omima; Urata, Yoshishige; Goto, Shinji; Guo, Chang-Ying; Luo, Lan; Abdelrahim, Eman; Ono, Yusuke; Mostafa, Emtethal; Li, Tao-Sheng

2014-01-01

Highlights: • Nicaraven mitigated the radiation-induced reduction of c-kit + stem cells. • Nicaraven enhanced the function of hematopoietic stem/progenitor cells. • Complex mechanisms involved in the protection of nicaraven to radiation injury. - Abstract: Nicaraven, a hydroxyl radical-specific scavenger has been demonstrated to attenuate radiation injury in hematopoietic stem cells with 5 Gy γ-ray exposures. We explored the effect and related mechanisms of nicaraven for protecting radiation injury induced by sequential exposures to a relatively lower dose γ-ray. C57BL/6 mice were given nicaraven or placebo within 30 min before exposure to 50 mGy γ-ray daily for 30 days in sequences (cumulative dose of 1.5 Gy). Mice were victimized 24 h after the last radiation exposure, and the number, function and oxidative stress of hematopoietic stem cells were quantitatively estimated. We also compared the gene expression in these purified stem cells from mice received nicaraven and placebo treatment. Nicaraven increased the number of c-kit + stem/progenitor cells in bone marrow and peripheral blood, with a recovery rate around 60–90% of age-matched non-irradiated healthy mice. The potency of colony forming from hematopoietic stem/progenitor cells as indicator of function was completely protected with nicaraven treatment. Furthermore, nicaraven treatment changed the expression of many genes associated to DNA repair, inflammatory response, and immunomodulation in c-kit + stem/progenitor cells. Nicaraven effectively protected against damages of hematopoietic stem/progenitor cells induced by sequential exposures to a relatively low dose radiation, via complex mechanisms

The potential benefits of nicaraven to protect against radiation-induced injury in hematopoietic stem/progenitor cells with relative low dose exposures

Energy Technology Data Exchange (ETDEWEB)

Ali, Haytham [Department of Stem Cell Biology, Atomic Bomb Disease Institute, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523 (Japan); Department of Medical Physiology and Cell Biology, Qena Faculty of Medicine, South Valley University (Egypt); Galal, Omima [Department of Medical Physiology and Cell Biology, Qena Faculty of Medicine, South Valley University (Egypt); Urata, Yoshishige; Goto, Shinji; Guo, Chang-Ying; Luo, Lan [Department of Stem Cell Biology, Atomic Bomb Disease Institute, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523 (Japan); Abdelrahim, Eman [Department of Medical Histology, Qena Faculty of Medicine, South Valley University (Egypt); Ono, Yusuke [Department of Stem Cell Biology, Atomic Bomb Disease Institute, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523 (Japan); Mostafa, Emtethal [Department of Medical Physiology and Cell Biology, Qena Faculty of Medicine, South Valley University (Egypt); Li, Tao-Sheng, E-mail: litaoshe@nagasaki-u.ac.jp [Department of Stem Cell Biology, Atomic Bomb Disease Institute, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523 (Japan)

2014-09-26

Highlights: • Nicaraven mitigated the radiation-induced reduction of c-kit{sup +} stem cells. • Nicaraven enhanced the function of hematopoietic stem/progenitor cells. • Complex mechanisms involved in the protection of nicaraven to radiation injury. - Abstract: Nicaraven, a hydroxyl radical-specific scavenger has been demonstrated to attenuate radiation injury in hematopoietic stem cells with 5 Gy γ-ray exposures. We explored the effect and related mechanisms of nicaraven for protecting radiation injury induced by sequential exposures to a relatively lower dose γ-ray. C57BL/6 mice were given nicaraven or placebo within 30 min before exposure to 50 mGy γ-ray daily for 30 days in sequences (cumulative dose of 1.5 Gy). Mice were victimized 24 h after the last radiation exposure, and the number, function and oxidative stress of hematopoietic stem cells were quantitatively estimated. We also compared the gene expression in these purified stem cells from mice received nicaraven and placebo treatment. Nicaraven increased the number of c-kit{sup +} stem/progenitor cells in bone marrow and peripheral blood, with a recovery rate around 60–90% of age-matched non-irradiated healthy mice. The potency of colony forming from hematopoietic stem/progenitor cells as indicator of function was completely protected with nicaraven treatment. Furthermore, nicaraven treatment changed the expression of many genes associated to DNA repair, inflammatory response, and immunomodulation in c-kit{sup +} stem/progenitor cells. Nicaraven effectively protected against damages of hematopoietic stem/progenitor cells induced by sequential exposures to a relatively low dose radiation, via complex mechanisms.

Radiation-induced brain damage in children

International Nuclear Information System (INIS)

Oi, Shizuo; Kokunai, Takashi; Ijichi, Akihiro; Matsumoto, Satoshi; Raimondi, A.J.

1990-01-01

The nature and sequence of the radiation-induced changes in the brain were studied postmortem in 34 children with glioma, 22 of whom underwent central nervous system radiation therapy. Twenty received whole-brain or whole-neuroaxis radiation at a total mean dosage of 4063 cGy. Brain tissue alternations were analyzed histologically by means of various staining methods, including immunohistochemical techniques. The histological features of irradiated brains were compared with those of non-irradiated brains. Microscopic findings included demyelination (seven cases), focal necrosis (six cases), cortical atrophy (four cases), endothelial proliferation (four cases), and telangiectatic vascular proliferation with vascular thickening and oozing of a thick fluid (one case). Such findings were rare in non-irradiated patients. Demyelination was observed earliest in a patient who died 5 months after radiation therapy and was more common after 9 months. Focal necrosis was first observed 9 months post-irradiation but was more advanced and extensive after 1 year. Calcified foci were found only after 60 months. Various vascular changes such as vascular thickening and thrombosis suggested ischemic insult to the brain as a late effect of radiation injury. The results of this study suggest that the immature brain may be more sensitive to radiation than is the adult brain, and that the manifestations of radiation-induced injury depend on the time elapsed after irradiation. (author)

Radiation-induced xerostomia in a patient with nasopharyngeal ...

African Journals Online (AJOL)

OBJECTIVE: This study reports a case of radiation-induced xerstomia in a patient with nasopharyngeal cancer, to emphasize the need for prompt oral care to prevent untoward effects of xerostomia and to improve patients' quality of life. CASE REPORT: A 60 year old man diagnosed of radiation-induced xerostomia, after 6 ...

Ionizing radiation induced genomic instability and its relation to radiation carcinogenesis

International Nuclear Information System (INIS)

Wang Zhongwen

2000-01-01

There are widespread testimonies that the genomic instability induced by ionizing irradiation exits in mammal and its vitro cells. Genomic instability can enhance the frequency of genetic changes among the progeny of the original irradiated cells. In the radiation-leukemogenesis, there is no significant difference between controls and CBA/H mouses of PPI (preconception patent irradiation), but the offsprings of the PPI recipients show a different character (shorter latent period and higher incidence) after an extra γ-radiation. The radiation-induced genomic instability may get the genome on the verge of mutation and lead to carcinogens following mutation of some critical genes. The genomic instability, as the early event of initiation of carcinomas, may be play a specific or unique role

Erratum to "Clinical evaluation of the intraoral fluoride releasing system in radiation-induced xerostomic subjects. Part 2: Phase I study".

Science.gov (United States)

Chambers, Mark S; Fleming, Terence J; Toth, Béla B; Lemon, James C; Craven, Timothy E; Bouwsma, Otis J; Garden, Adam S; Espeland, Mark A; Keene, Harris J; Martin, Jack W; Sipos, Tibor

2007-01-01

Radiation-induced xerostomia can result in the rapid onset and progression of dental caries in head and neck cancer patients. Topically applied fluorides have been successfully used to inhibit the formation of dental caries in this population. However, because intensive daily self-application is required, compliance is an issue. The intraoral fluoride-releasing system (IFRS) containing a sodium fluoride core is a newly developed, sustained-release, passive drug delivery system that does not require patient involvement except for periodic replacement, thus reducing the effect of patient compliance on its effectiveness in dental caries prevention. Twenty-two head and neck cancer patients from U. T. M. D. Anderson Cancer Center, with radiation-induced xerostomia, were entered into a pilot study to contrast the daily home use of a 0.4% stannous fluoride-gel-containing tray (control group) to IFRS (study group) with respect to tolerability and adherence, and to obtain information on relative caries preventive efficacy. Participants were stratified on the basis of radiation exposure and randomly assigned to treatment with either IFRS or stannous fluoride gel. Patients in both groups were fitted with two IFRS retainers and also were instructed to use a 1100-ppm fluoride conventional sodium fluoride dentifrice twice daily. The study was conducted as a single-blinded, parallel-cell trial. Pre-existing carious lesions were restored prior to the beginning of the study. The efficacy variable was determined by the mean number of new or recurrent decayed surfaces. Patients were examined for caries 4, 8, 12, 24, 36, and 48 weeks after initiation of treatment. Reports of adverse reactions were based on information volunteered by patients and that were elicited during interviews. At baseline, the resting and stimulated salivary flow rates (g/5min) were significantly greater in the control group than in the study group (pIFRS groups during the study period. The rate of new or

Influence of the formation- and passivation rate of boron-oxygen defects for mitigating carrier-induced degradation in silicon within a hydrogen-based model

International Nuclear Information System (INIS)

Hallam, Brett; Abbott, Malcolm; Nampalli, Nitin; Hamer, Phill; Wenham, Stuart

2016-01-01

A three-state model is used to explore the influence of defect formation- and passivation rates of carrier-induced degradation related to boron-oxygen complexes in boron-doped p-type silicon solar cells within a hydrogen-based model. The model highlights that the inability to effectively mitigate carrier-induced degradation at elevated temperatures in previous studies is due to the limited availability of defects for hydrogen passivation, rather than being limited by the defect passivation rate. An acceleration of the defect formation rate is also observed to increase both the effectiveness and speed of carrier-induced degradation mitigation, whereas increases in the passivation rate do not lead to a substantial acceleration of the hydrogen passivation process. For high-throughput mitigation of such carrier-induced degradation on finished solar cell devices, two key factors were found to be required, high-injection conditions (such as by using high intensity illumination) to enable an acceleration of defect formation whilst simultaneously enabling a rapid passivation of the formed defects, and a high temperature to accelerate both defect formation and defect passivation whilst still ensuring an effective mitigation of carrier-induced degradation

Bovine chromosomal regions affecting rheological traits in rennet-induced skim milk gels

DEFF Research Database (Denmark)

Gregersen, Vivi Raundahl; Gustavsson, F; Glantz, M

2015-01-01

genomic regions affecting traits related to rennet-induced gelation, the aim of this study was to identify potential candidate genes affecting these traits. Hence, rennet-induced gelation, including rennet coagulation time, gel strength, and yield stress, was measured in skim milk samples collected from...... 379 animals of the Swedish Red breed using low-amplitude oscillation measurements. All animals had genotypes for almost 621,000 segregating single nucleotide polymorphisms (SNP), identified using the Bovine HD SNPChip (Illumina Inc., San Diego, CA). The genome was scanned for associations, haplotypes...... based on SNP sets comprising highly associated SNP were inferred, and the effects of the 2 most common haplotypes within each region were analyzed using mixed models. Even though the number of animals was relatively small, a total of 21 regions were identified, with 4 regions showing association...

Radiation-induced valvular heart disease.

Science.gov (United States)

Gujral, Dorothy M; Lloyd, Guy; Bhattacharyya, Sanjeev

2016-02-15

Radiation to the mediastinum is a key component of treatment with curative intent for a range of cancers including Hodgkin's lymphoma and breast cancer. Exposure to radiation is associated with a risk of radiation-induced heart valve damage characterised by valve fibrosis and calcification. There is a latent interval of 10-20 years between radiation exposure and development of clinically significant heart valve disease. Risk is related to radiation dose received, interval from exposure and use of concomitant chemotherapy. Long-term outlook and the risk of valve surgery are related to the effects of radiation on mediastinal structures including pulmonary fibrosis and pericardial constriction. Dose prediction models to predict the risk of heart valve disease in the future and newer radiation techniques to reduce the radiation dose to the heart are being developed. Surveillance strategies for this cohort of cancer survivors at risk of developing significant heart valve complications are required. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Caffeine Mitigates Lung Inflammation Induced by Ischemia-Reperfusion of Lower Limbs in Rats

Directory of Open Access Journals (Sweden)

Wei-Chi Chou

2015-01-01

Full Text Available Reperfusion of ischemic limbs can induce inflammation and subsequently cause acute lung injury. Caffeine, a widely used psychostimulant, possesses potent anti-inflammatory capacity. We elucidated whether caffeine can mitigate lung inflammation caused by ischemia-reperfusion (IR of the lower limbs. Adult male Sprague-Dawley rats were randomly allocated to receive IR, IR plus caffeine (IR + Caf group, sham-operation (Sham, or sham plus caffeine (n=12 in each group. To induce IR, lower limbs were bilaterally tied by rubber bands high around each thigh for 3 hours followed by reperfusion for 3 hours. Caffeine (50 mg/kg, intraperitoneal injection was administered immediately after reperfusion. Our histological assay data revealed characteristics of severe lung inflammation in the IR group and mild to moderate characteristic of lung inflammation in the IR + Caf group. Total cells number and protein concentration in bronchoalveolar lavage fluid of the IR group were significantly higher than those of the IR + Caf group (P<0.001 and P=0.008, resp.. Similarly, pulmonary concentrations of inflammatory mediators (tumor necrosis factor-α, interleukin-1β, and macrophage inflammatory protein-2 and pulmonary myeloperoxidase activity of the IR group were significantly higher than those of the IR + Caf group (all P<0.05. These data clearly demonstrate that caffeine could mitigate lung inflammation induced by ischemia-reperfusion of the lower limbs.

Effectiveness of the herbal medicine daikenchuto for radiation-induced enteritis.

Science.gov (United States)

Takeda, Takashi; Kamiura, Shouji; Kimura, Tadashi

2008-07-01

Radiation-induced enteritis is a serious clinical problem for which there is currently no recommended standard management. Daikenchuto (DKT) is a Japanese herbal medicine that has been used to treat adhesive bowel obstruction in Japan. This report describes a patient with radiation-induced enteritis whose clinical symptoms were much improved by treatment with DKT. The patient was administered DKT, a traditional Japanese herbal formula, orally (2.5 g 3 times daily). Abdominal distention was evaluated objectively with computed tomography. Gastrointestinal symptoms associated with radiation-induced enteritis were controlled successfully with DKT treatment. DKT treatment may be useful for the management of radiation-induced enteritis.

Radiation levels at CERN's injectors and their impact on electronic equipment

CERN Document Server

AUTHOR|(SzGeCERN)649218; Brugger, Markus

2013-01-01

Electronic devices operating in hostile radiation environments, such as those found close to high-energy particle accelerators, can suffer from different types of radiation induced failures. At CERN, the mixed particle and energy radiation fields present at the Large Hadron Collider (LHC) and its injector chain can give rise to both stochastic and cumulative effects causing radiation induced failures of exposed electronics and materials, thus directly impacting components and system lifetimes, as well as maintenance requirements. With its original focus on the LHC, the Radiation to Electronics (R2E) project has been successfully implementing mitigation actions in order to avoid accelerator downtime due to radiation induced failures on active electronics. In a next step, the emphasis is put on CERN's injector chain, collecting the respective available information about radiation levels, the definition of additional monitoring requirements and a critical analysis of present and future equipment installations. T...

Kinetics of radiation-induced segregation in ternary alloys

International Nuclear Information System (INIS)

Lam, N.O.; Kumar, A.; Wiedersich, H.

1982-01-01

Model calculations of radiation-induced segregation in ternary alloys have been performed, using a simple theory. The theoretical model describes the coupling between the fluxes of radiation-induced defects and alloying elements in an alloy A-B-C by partitioning the defect fluxes into those occurring via A-, B-, and C-atoms, and the atom fluxes into those taking place via vacancies and interstitials. The defect and atom fluxes can be expressed in terms of concentrations and concentration gradients of all the species present. With reasonable simplifications, the radiation-induced segregation problem can be cast into a system of four coupled partial-differential equations, which can be solved numerically for appropriate initial and boundary conditions. Model calculations have been performed for ternary solid solutions intended to be representative of Fe-Cr-Ni and Ni-Al-Si alloys under various irradiation conditions. The dependence of segregation on both the alloy properties and the irradiation variables, e.g., temperature and displacement rate, was calculated. The sample calculations are in good qualitative agreement with the general trends of radiation-induced segregation observed experimentally

Study of effects of radiation on silicone prostheses

International Nuclear Information System (INIS)

Shedbalkar, A.R.; Devata, A.; Padanilam, T.

1980-01-01

Radiation effects on silicone gel and dose distribution of radiation through mammary prostheses were studied. Silicone gel behaves like tissue. Half value thickness for silicone gel and water are almost the same. Linear absorption coefficient for silicone gel and water are comparable

Seven cases of radiation-induced cutaneous squamous cell carcinoma

Energy Technology Data Exchange (ETDEWEB)

Sugita, Kazunari; Yamamoto, Osamu; Suenaga, Yoshinori [Univ. of Occupational and Environmental Health, Kitakyushu, Fukuoka (Japan). School of Medicine

2000-09-01

We report 7 cases of radiation-induced skin cancer. The diagnosis was based on the history of radiotherapy for benign skin diseases (5 cases) and of occupational exposures to medical doctors (2 cases). All cases were squamous cell carcinomas which arose from chronic radiodermatitis. The estimated latent period of these tumors ranged from 6 to 64 years, with an average of 29.9 years. After surgical treatments of the lesions, no local recurrences were observed in all cases. Benign skin diseases had sometimes been treated with low-energy radiation before the 1960s. Considering the estimated latent period, the peak time point of developing risk of radiation-induced skin cancer by such treatment has been already passed, however, the danger of it should not be ignored in future. In association with multiplicity of radiation usage, occupational exposure of radiation may develop the risk of occurrence of skin cancer in future. Therefore, we should recognize that radiation-induced skin cancer is not in the past. In the cases of chronic skin diseases showing warty keratotic growth, erosion and ulcer, we should include chronic radio-dermatitis in the differential diagnosis. It is necessary to recall all patients about the history of radiotherapy or radiation exposure. Rapid histopathological examination is mandatory because of the suspicion of radiation-induced skin cancer. (author)

Seven cases of radiation-induced cutaneous squamous cell carcinoma

International Nuclear Information System (INIS)

Sugita, Kazunari; Yamamoto, Osamu; Suenaga, Yoshinori

2000-01-01

We report 7 cases of radiation-induced skin cancer. The diagnosis was based on the history of radiotherapy for benign skin diseases (5 cases) and of occupational exposures to medical doctors (2 cases). All cases were squamous cell carcinomas which arose from chronic radiodermatitis. The estimated latent period of these tumors ranged from 6 to 64 years, with an average of 29.9 years. After surgical treatments of the lesions, no local recurrences were observed in all cases. Benign skin diseases had sometimes been treated with low-energy radiation before the 1960s. Considering the estimated latent period, the peak time point of developing risk of radiation-induced skin cancer by such treatment has been already passed, however, the danger of it should not be ignored in future. In association with multiplicity of radiation usage, occupational exposure of radiation may develop the risk of occurrence of skin cancer in future. Therefore, we should recognize that radiation-induced skin cancer is not in the past. In the cases of chronic skin diseases showing warty keratotic growth, erosion and ulcer, we should include chronic radio-dermatitis in the differential diagnosis. It is necessary to recall all patients about the history of radiotherapy or radiation exposure. Rapid histopathological examination is mandatory because of the suspicion of radiation-induced skin cancer. (author)

Radiation induced crosslinking of cellulose ethers

International Nuclear Information System (INIS)

Wach, A.R.; Mitomo, H.; Yoshii, F.; Kume, T.

2002-01-01

The effects of high-energy radiation on four ethers of cellulose: carboxymethyl (CMC); hydroxypropyl (HPC), hydroxyethyl (HEC) and methylcellulose (MC) were investigated. Polymers are irradiated in solid state and in aqueous solutions at various concentrations. Degree of substitution (DS) of the derivatives, the concentration of their aqueous solutions and irradiation conditions had a significant impact on the obtained products. Irradiation of polymers in solid state and in diluted aqueous solutions resulted in their degradation. However, it was found that for concentrated solutions gel formation occurred. Paste-like form of the initial material, when water plasticizes the bulk of polymer as well as the high dose rate, what prevents oxygen penetration of the polymer during irradiation, have been found favourable for hydrogel formation. Up to 95% of gel fraction was obtained from solutions of CMC with concentration over 50% irradiated by γ-rays or electron beam. It was pointed out that the ability to the formation of the three-dimensional network is related to the DS of anhydroglucose units and a type of chemical group introduced to main chain of cellulose. Produced hydrogels swelled markedly in water. Despite of the crosslinked structure they underwent degradation by the action of cellulase enzyme or microorganisms from compost, and can be included into the group of biodegradable materials. (author)

Public health activities for mitigation of radiation exposures and risk communication challenges after the Fukushima nuclear accident

International Nuclear Information System (INIS)

Shimura, Tsutomu; Yamaguchi, Ichiro; Terada, Hiroshi; Kunugita, Naoki; Svendsen, Erik Robert

2015-01-01

Herein we summarize the public health actions taken to mitigate exposure of the public to radiation after the Fukushima accident that occurred on 11 March 2011 in order to record valuable lessons learned for disaster preparedness. Evacuations from the radiation-affected areas and control of the distribution of various food products contributed to the reduction of external and internal radiation exposure resulting from the Fukushima incident. However, risk communication is also an important issue during the emergency response effort and subsequent phases of dealing with a nuclear disaster. To assist with their healing process, sound, reliable scientific information should continue to be disseminated to the radiation-affected communities via two-way communication. We will describe the essential public health actions following a nuclear disaster for the early, intermediate and late phases that will be useful for radiological preparedness planning in response to other nuclear or radiological disasters. (author)

Obtention of gelatin biopolymers by ionizing radiation; Obtencao de biopolimeros de gelatina por radiacao ionizante

Energy Technology Data Exchange (ETDEWEB)

Takinami, Patricia Yoko Inamura

2014-07-01

The gelatin (Gel) is a biocompatible and biodegradable biopolymer, which naturally forms semi-solid colloids or hydrogels in aqueous solutions. As a hydrophilic polymer, the Gel has structural and physico-mechanical properties that distinguish it from synthetic hydrophilic polymers. The study of these properties led to the development of the present work. Thus, Gel-based films and hydrogels were developed using ionizing radiation technology by different techniques: irradiation with {sup 60}Co, electron beam (EB) and/or pulsed EB. The Gel based-films enriched with different additives, such as glycerol (GLY), polyvinyl alcohol (PVA), butylated hydroxytoluene (BHT), acrylamide and/or vegetal fiber, were irradiated with doses from 10 to 60 kGy, depending on the additive; some parameters like mechanical properties, color, and water absorption were analyzed. In the radio-induced synthesis of GEL nanohydrogels, polyethylene glycol (PEG) and the mixture (MIX) of additives, PEG and GEL, the size, molar mass and surface morphology of the nanohydrogels were analyzed. There was a significant increase of gel fraction with increase of the radiation dose for the GEL/fiber samples. The GEL based-films with 10% PVA irradiated at 20 kGy showed the highest puncture strength. The addition of antioxidant BHT affected on some GEL based-films properties on applied conditions. Regarding the nanohydrogels, there was a decrease of hydrodynamic radius of MIX irradiated with {sup 60}Co from 68 ± 25 nm (2 kGy) to 35 ± 4 nm (5 kGy). The radiation proved to be a convenient tool in the modification of polymeric materials for both, GEL films and hydrogels. (author)

Membrane phospholipids and radiation-induced death of mammalian cells

International Nuclear Information System (INIS)

Wolters, H.

1987-01-01

Radiation-induced cell killing is generally believed to be a consequence of residual DNA damage or damage that is mis-repaired. However, besides this DNA damage, damage to other molecules or structures of the cell may be involved in the killing. Especially membranes have been suggested as a determinant in cellular radiosensitivity. In this thesis experiments are described, dealing with the possible involvement of membranes in radiation-induced killing of mammalian cells. A general treatise of membrane structure is followed by information concerning deleterious effects of radiation on membranes. Consequences of damage to structure and function of membranes are reviewed. Thereafter evidence relating to the possible involvement of membranes in radiation-induced cell killing is presented. (Auth.)

Radiation-induced alternative transcripts as detected in total and polysome-bound mRNA.

Science.gov (United States)

Wahba, Amy; Ryan, Michael C; Shankavaram, Uma T; Camphausen, Kevin; Tofilon, Philip J

2018-01-02

Alternative splicing is a critical event in the posttranscriptional regulation of gene expression. To investigate whether this process influences radiation-induced gene expression we defined the effects of ionizing radiation on the generation of alternative transcripts in total cellular mRNA (the transcriptome) and polysome-bound mRNA (the translatome) of the human glioblastoma stem-like cell line NSC11. For these studies, RNA-Seq profiles from control and irradiated cells were compared using the program SpliceSeq to identify transcripts and splice variations induced by radiation. As compared to the transcriptome (total RNA) of untreated cells, the radiation-induced transcriptome contained 92 splice events suggesting that radiation induced alternative splicing. As compared to the translatome (polysome-bound RNA) of untreated cells, the radiation-induced translatome contained 280 splice events of which only 24 were overlapping with the radiation-induced transcriptome. These results suggest that radiation not only modifies alternative splicing of precursor mRNA, but also results in the selective association of existing mRNA isoforms with polysomes. Comparison of radiation-induced alternative transcripts to radiation-induced gene expression in total RNA revealed little overlap (about 3%). In contrast, in the radiation-induced translatome, about 38% of the induced alternative transcripts corresponded to genes whose expression level was affected in the translatome. This study suggests that whereas radiation induces alternate splicing, the alternative transcripts present at the time of irradiation may play a role in the radiation-induced translational control of gene expression and thus cellular radioresponse.

Aloe vera gel provides protection to Swiss albino mice against radiation induced injury

International Nuclear Information System (INIS)

Saini, D.K.; Chaudhary, G.; Saini, M.R.

2007-01-01

Aloe gel powder was administered orally to Swiss albino mice at the dose of 250, 500 and 750 mg/kg body weight/day for 15 consecutive days with and without irradiation with 8 Gy to find out its maximum effective radioprotective dose. 30 days survivality and change in levels of lipid peroxidation (LPO), reduced glutathione (GSH) and vitamin C were studied at 1 hour and 30 days for this purpose. In Aloe treated (750 mg/kg b. wt.) 8 Gy irradiated animals 30 days survivality, contents of GSH and vitamin C were higher and LPO level was lesser at 1 hour and 30 days in comparison to those treated with Aloe at the dose of 250 and 500 mg/kg body weight and irradiated with 8 Gy. These results indicate that Aloe administration at the dose of 750 mg/kg body weight was found to be the most effective

Non-targeted bystander effects induced by ionizing radiation

International Nuclear Information System (INIS)

Morgan, William F.; Sowa, Marianne B.

2007-01-01

Radiation-induced bystander effects refer to those responses occurring in cells that were not subject to energy deposition events following ionizing radiation. These bystander cells may have been neighbors of irradiated cells, or physically separated but subject to soluble secreted signals from irradiated cells. Bystander effects have been observed in vitro and in vivo and for various radiation qualities. In tribute to an old friend and colleague, Anthony V. Carrano, who would have said 'well what are the critical questions that should be addressed, and so what?', we review the evidence for non-targeted radiation-induced bystander effects with emphasis on prevailing questions in this rapidly developing research field, and the potential significance of bystander effects in evaluating the detrimental health effects of radiation exposure

Radiation-induced hondrosarcoma - a clinical case from our practice

International Nuclear Information System (INIS)

Marinova, L.; Georgiev, R.; Mihaylova, I.

2013-01-01

We present a clinical case of radiation - induced occipital extracerebral chondrosarcoma in 36 years old young man. The patient had undergone two brain operations 8 years ago due to oligodendroglioma in the left temporo - parietal area. These surgical interventions were partial and subtotal tumor extirpation, followed by local radiotherapy to the brain to a total dose of 56Gy. The necessity of immunohistochemistry (IHH) analysis for pathologic differential diagnosis in high grade brain and peripheral tumors was discussed. In this particular case a precise differential diagnosis between peripheral chondrosarcoma and Ewing sarcoma/pPNET is needed. important risk factors for the development of radiation-induced brain tumors and chondrosarcoma, extremely rarely diagnosed, was discussed. A very accurate precising of the treatment radiation dose is needed in young patients with malignant brain tumors, not only in the surrounding healthy brain tissues, but also in other tissues, such as skin, subcutaneous layer and bone. The exceeding of the radiation dose in the bone above 45-50 Gy, increases the risk of radiation - induced sarcoma with latent period over 8 years. Key words: Hondrosarcoma. Radiotherapy. Radiation-induced Sarcoma. Complex Treatment. Immunohistochemistry

Bile acids in radiation-induced diarrhea

International Nuclear Information System (INIS)

Arlow, F.L.; Dekovich, A.A.; Priest, R.J.; Beher, W.T.

1987-01-01

Radiation-induced bowel disease manifested by debilitating diarrhea is an unfortunate consequence of therapeutic irradiation for pelvic malignancies. Although the mechanism for this diarrhea is not well understood, many believe it is the result of damage to small bowel mucosa and subsequent bile acid malabsorption. Excess amounts of bile acids, especially the dihydroxy components, are known to induce water and electrolyte secretion and increase bowel motility. We have directly measured individual and total bile acids in the stool samples of 11 patients with radiation-induced diarrhea and have found bile acids elevated two to six times normal in eight of them. Our patients with diarrhea and increased bile acids in their stools had prompt improvement when given cholestyramine. They had fewer stools and returned to a more normal life-style

Ionizing radiation induces stemness in cancer cells.

Directory of Open Access Journals (Sweden)

Laura Ghisolfi

Full Text Available The cancer stem cell (CSC model posits the presence of a small number of CSCs in the heterogeneous cancer cell population that are ultimately responsible for tumor initiation, as well as cancer recurrence and metastasis. CSCs have been isolated from a variety of human cancers and are able to generate a hierarchical and heterogeneous cancer cell population. CSCs are also resistant to conventional chemo- and radio-therapies. Here we report that ionizing radiation can induce stem cell-like properties in heterogeneous cancer cells. Exposure of non-stem cancer cells to ionizing radiation enhanced spherogenesis, and this was accompanied by upregulation of the pluripotency genes Sox2 and Oct3/4. Knockdown of Sox2 or Oct3/4 inhibited radiation-induced spherogenesis and increased cellular sensitivity to radiation. These data demonstrate that ionizing radiation can activate stemness pathways in heterogeneous cancer cells, resulting in the enrichment of a CSC subpopulation with higher resistance to radiotherapy.

Apparatus and Methods for Mitigating Electromagnetic Emissions

Science.gov (United States)

Geng, Steven M. (Inventor); Niedra, Janis M. (Inventor)

2016-01-01

Apparatus, methods, and other embodiments associated with mitigation of magnetic fields are described herein. In an embodiment, a method for mitigating an electromagnetic field includes positioning a mitigating coil around a linear alternator of linear motor so that the mitigating coil is coaxially located with an alternator coil; arranging the mitigating coil to generate a field to mitigate an electromagnetic field generated by the alternator coil; and passing an induced current from the alternator coil through the mitigating coil.

Molecular dosimetry based on radiation induced degradation of polyisobutylene

International Nuclear Information System (INIS)

Joerkov Thomsen, Kristina

1999-01-01

This project investigates the possibility of qualitative measurement of radiation doses through detection of changes in the average molecular weight in the polymer Polyisobutylene (PIB). Changes in molecular weight and molecular weight distribution is detected by Gel Permeation Chromatography (GPC). The aim of the project is to decide whether or not it is possible to determine a quality difference between α-radiation ( 241 Am, 5,5 MeV) and γ-radiation ( 60 Co, 1,25 MeV) in the dose range 0,5 to 10 kGy by irradiation of PIB. Irradiation with 60 Co changes the average number molecular weight M n by 12% per kGy and the average weight molecular weight M w by 23% per kGy. The presence of antioxidant in the irradiated sample inhibits a change in average molecular weight by 5% and 16% for M n and M w respectively. (au)

ON01210.Na (Ex-RAD® mitigates radiation damage through activation of the AKT pathway.

Directory of Open Access Journals (Sweden)

Anthony D Kang

Full Text Available Development of radio-protective agents that are non-toxic is critical in light of ever increasing threats associated with proliferation of nuclear materials, terrorism and occupational risks associated with medical and space exploration. In this communication, we describe the discovery, characterization and mechanism of action of ON01210.Na, which effectively protects mouse and human bone marrow cells from radiation-induced damage both in vitro and in vivo. Our results show that treatment of normal fibroblasts with ON01210.Na before and after exposure to ionizing radiation provides dose dependent protection against radiation-induced damage. Treatment of mice with ON01210.Na prior to radiation exposure was found to result in a more rapid recovery of their hematopoietic system. The mechanistic studies described here show that ON01210.Na manifests its protective effects through the up-regulation of PI3-Kinase/AKT pathways in cells exposed to radiation. These results suggest that ON 01210.Na is a safe and effective radioprotectant and could be a novel agent for use in radiobiological disasters.

Specitic gene alterations in radiation-induced tumorigenesis

Energy Technology Data Exchange (ETDEWEB)

Ahn, Joo Mee; Kang, Chang Mo; Lee, Seung Sook; Cho, Chul Koo; Bae, Sang Woo; Lee, Su Jae; Lee, Yun Sil [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

2004-07-01

To identify a set of genes involved in the development of radiation-induced tumorigenesis, we used DNA microarrays consisting of 1,176 mouse genes and compared expression profiles of radioresistant cells, designated NIH3T3-R1 and -R4. These cells were tumorigenic in a nude mouse grafting system, as compared to the parental NIH3T3 cells. Expressions of MDM2, CDK6 and CDC25B were found to increase more than 3-fold. Entactin protein levels were downregulated in NIH3T3-R1 and -R4 cells. Changes in expression genes were confirmed by reverse transcription-PCR or western blotting. When these genes were transfected to NIH3T3 cells, the CDC25B and MDM2 overexpressing NIH3T3 cells showed radioresistance, while 2 CDK6 overexpressing cells did not. In the case of entactin overexpressing NIH3T3-R1 or R-4 cells were still radioresistant. Furthermore, the CDC25B and MDM2 overexpressing cells grafted to nude mice, were tumorigenic. NIH3T3-R1 and R4 cells showed increased radiation-induced apoptosis, accompanied by faster growth rate, rather than and earlier radiation-induced G2/M phase arrest, suggesting that the radioresistance of NIH3T3-R1 and R4 cells was due to faster growth rate, rather than induction of apoptosis. In the case of MDM2 and CDC25B overexpressing cells, similar phenomena, such as increased apoptosis and faster growth rate, were shown. The above results, therefore, demonstrate involvement of CDC25B and MDM2 overexpression in radiation-induced tumorigenesis and provide novel targets for detection of radiation-induced carcinogenesis.

Three dimensional gel dosimetry by use of nuclear magnetic resonance imaging (MRI)

Energy Technology Data Exchange (ETDEWEB)

De Deene, Y; De Wagter, C; Van Duyse, B; Achten, E; De Neve, W [Ghent Rijksuniversiteit (Belgium). Kliniek voor Radiotherapie en Kerngeneeskunde; De Poorter, J [Ghent Univ. (Belgium). Dept. of Magnetic Resonance

1995-12-01

As co-monomers are found to polymerize by radiation, they are eligible for constructing a three dimensional dosimeter. Another kind of three dimensional dosimeter, based on the radiation sensitivity of the ferrous ions in a Fricke solution, was tested in a previous study. However, a major problem that occurs in this kind of gel dosimeters is the diffusion of the ferric and ferrous ions. The co-monomer gels are more stable. The degree of polymerisation is visualized with a clinical MRI system. Acrylamide and N,N-methylene-bis-acrylamide are dissolved in a gel composed of gelatin and water. By irradiation the co-monomers are polymerized to polyacrylamide. The gel is casted in humanoid forms. As such, a simulation of the irradiation of the patient can be performed. Magnetic resonance relaxivity images of the irradiated gel display the irradiation dose. The images of the gel are fused with the radiological images of the patient. Quantitation of the dose response of the co-monomer gel is obtained through calibration by test tubes.

Three dimensional gel dosimetry by use of nuclear magnetic resonance imaging (MRI)

International Nuclear Information System (INIS)

De Deene, Y.; De Wagter, C.; Van Duyse, B.; Achten, E.; De Neve, W.; De Poorter, J.

1995-01-01

As co-monomers are found to polymerize by radiation, they are eligible for constructing a three dimensional dosimeter. Another kind of three dimensional dosimeter, based on the radiation sensitivity of the ferrous ions in a Fricke solution, was tested in a previous study. However, a major problem that occurs in this kind of gel dosimeters is the diffusion of the ferric and ferrous ions. The co-monomer gels are more stable. The degree of polymerisation is visualized with a clinical MRI system. Acrylamide and N,N-methylene-bis-acrylamide are dissolved in a gel composed of gelatin and water. By irradiation the co-monomers are polymerized to polyacrylamide. The gel is casted in humanoid forms. As such, a simulation of the irradiation of the patient can be performed. Magnetic resonance relaxivity images of the irradiated gel display the irradiation dose. The images of the gel are fused with the radiological images of the patient. Quantitation of the dose response of the co-monomer gel is obtained through calibration by test tubes

Induced Compton-scattering effects in radiation-transport approximations

International Nuclear Information System (INIS)

Gibson, D.R. Jr.

1982-02-01

The method of characteristics is used to solve radiation transport problems with induced Compton scattering effects included. The methods used to date have only addressed problems in which either induced Compton scattering is ignored, or problems in which linear scattering is ignored. Also, problems which include both induced Compton scattering and spatial effects have not been considered previously. The introduction of induced scattering into the radiation transport equation results in a quadratic nonlinearity. Methods are developed to solve problems in which both linear and nonlinear Compton scattering are important. Solutions to scattering problems are found for a variety of initial photon energy distributions

Simulating Space Radiation-Induced Breast Tumor Incidence Using Automata.

Science.gov (United States)

Heuskin, A C; Osseiran, A I; Tang, J; Costes, S V

2016-07-01

Estimating cancer risk from space radiation has been an ongoing challenge for decades primarily because most of the reported epidemiological data on radiation-induced risks are derived from studies of atomic bomb survivors who were exposed to an acute dose of gamma rays instead of chronic high-LET cosmic radiation. In this study, we introduce a formalism using cellular automata to model the long-term effects of ionizing radiation in human breast for different radiation qualities. We first validated and tuned parameters for an automata-based two-stage clonal expansion model simulating the age dependence of spontaneous breast cancer incidence in an unexposed U.S. We then tested the impact of radiation perturbation in the model by modifying parameters to reflect both targeted and nontargeted radiation effects. Targeted effects (TE) reflect the immediate impact of radiation on a cell's DNA with classic end points being gene mutations and cell death. They are well known and are directly derived from experimental data. In contrast, nontargeted effects (NTE) are persistent and affect both damaged and undamaged cells, are nonlinear with dose and are not well characterized in the literature. In this study, we introduced TE in our model and compared predictions against epidemiologic data of the atomic bomb survivor cohort. TE alone are not sufficient for inducing enough cancer. NTE independent of dose and lasting ∼100 days postirradiation need to be added to accurately predict dose dependence of breast cancer induced by gamma rays. Finally, by integrating experimental relative biological effectiveness (RBE) for TE and keeping NTE (i.e., radiation-induced genomic instability) constant with dose and LET, the model predicts that RBE for breast cancer induced by cosmic radiation would be maximum at 220 keV/μm. This approach lays the groundwork for further investigation into the impact of chronic low-dose exposure, inter-individual variation and more complex space radiation

MAJOR OUTCOMES OF THE WORK PERFORMED BY ST. PETERSBURG RESEARCH INSTITUTE OF RADIATION HYGIENE AFTER PROFESSOR P. V. RAMZAEV ON THE IMPLEMENTATION OF THE FEDERAL TARGETED PROGRAM “MITIGATION OF THE RADIATION ACCIDENTS’CONSEQUENCES UNTIL 2015” AND OF THE “JOINT ACTIVITIES PROGRAM ON MITIGATION OF THE CHERNOBYL DISASTER WITHIN THE UNION STATE FOR THE PERIOD UNTIL 2016“

Directory of Open Access Journals (Sweden)

A. N. Barkovskiy

2016-01-01

Full Text Available The article presents major results of the work performed by St. Petersburg Research Institute of Radiation Hygiene after Professor P. V. Ramzaev on public contracts signed within the implementation of the Federal targeted program “ Mitigation of the radiation accidents’ consequences for the period until 2015” ( Direction IV “ Streamlining of monitoring systems and their elements and situation forecasting on radioactively contaminated territories paragraph 14 “The analyses and comprehensive evaluation of radiation situation changes on radioactively contaminated territories “ aimed at compilation of radioactively contaminated zones’ settlements list and Direction VI “Awareness raising and social -psychological rehabilitation of radiation- affected residents”, paragraph 20 “Creation of unified informational system on ensuring population’s radiation safety and overcoming radiation accidents’ consequences via development of the federal and regional informational resources’ systems” and “ Joint activities program on mitigation of the Chernobyl disaster within the Union State for the period until 2016” ( Direction II “ Streamlining of unified radiation protection system in radioactively contaminated territories” paragraph 2.1 “ The harmonization of requirements, methods and technologies aimed at mitigation of Russian and Belorussian population’s internal and external exposure, the development of radiation control and monitoring unified system”, sub-paragraph 2.1.1 “The development of unified assessment and forecast system for population exposure doses and rationing of radionuclide – containing foodstuffs, agricultural products and forest preserves based on the international approaches” over the period from 2011 to 2015.