Note: This page contains sample records for the topic radiation induced crystallinity from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: August 15, 2014.
1

Radiation induced crystallinity damage in poly( L-lactic acid)  

NASA Astrophysics Data System (ADS)

The radiation-induced crystallinity damage in poly( L-lactic acid) (PLLA) in the presence of air and in vacuum, is studied. From the heat of fusion enthalpy values of gamma irradiated samples, some changes on the thermal properties were determined. To identify these changes, first the glass transition temperature ( Tg) of L-lactic acid polymers irradiated to various doses in air and vacuum have been investigated and it is found that it is independent of irradiation atmosphere and dose. The fraction of damaged units of PLLA per unit of absorbed energy has been measured. For this purpose, SAXS and differential scanning calorimetry methods were used, and the radiation yield of number of damaged units ( G(- u)) is found to be 0.74 and 0.58 for PLLA samples irradiated in vacuum and air, respectively.

Kanto?lu, Ömer; Güven, Olgun

2002-12-01

2

Radiation-induced Precursors in Crystalline Energetic Composites  

NASA Astrophysics Data System (ADS)

We present new experimental evidence that demonstrates the origination of precursors of the major reaction front at SDT in PBXs, based on the results of wedge tests of the HMX/Epoxy 77/23 (wt. %) and HMX/Water composites. The precursors were spatially resolved in the modified wedge tests performed with the Multi-Channel Optical Analyzer -- MCOA by means of the simultaneous registration of the reaction radiance transmitting through the explosive bulk at the SDT and the stress field, which is induced by the reaction zone in the optical monitor. Experimental evidence, obtained at a wide variation of the HMX particle sizes (1.64 ?m < d50 < 960 ?m), point to the fact that the precursor is arisen as a result of the radiation heating due to the photon absorption, as the reaction radiation is scattered within the bulk of the crystalline explosive material. Within the precursor layer, thickness of which depends on both, temperature localization and radiation intensity in the major DRZ as well as on optical and kinetic properties (the photon absorption and further reactivity of the explosive particles), the explosive particles undergo thermal expansion, phase transformation and partial decomposition. Such a mechanism implies that the photo-excitation and energy localization due to radiation of the shock front play a crucial role in starting decomposition process.

Plaksin, I.; Rodrigues, L.; Plaksin, S.; Campos, J.; Mendes, R.; Ribeiro, J.; Gois, J.

2009-06-01

3

Radiation-Induced Precursors in Crystalline Energetic Composites  

NASA Astrophysics Data System (ADS)

Effect of the absorbed reaction light on the formation of the DRZ 3D-structure during the SDT was studied in the wedge tests of PBXs ``HMX 77/23 wt. % Epoxy,'' ten times distinguished by the grain size, 49 ?m vs. 507 ?m. Experimental evidence point to the fact that the precursor of the major front is arisen as a result of the photo-excitation and radiation heating due to the photon absorption, as the reaction radiation is scattered within the bulk of the crystalline explosive material.

Plaksin, I.; Rodrigues, L.; Plaksin, S.; Campos, J.; Mendes, R.; Ribeiro, J.; Gois, J.

2009-12-01

4

Tryptophan Cluster Protects Human ?D-Crystallin from Ultraviolet Radiation-Induced Photoaggregation In Vitro  

PubMed Central

Exposure to ultraviolet radiation (UVR) is a significant risk factor for age-related cataract, a disease of the human lens and the most prevalent cause of blindness in the world. Cataract pathology involves protein misfolding and aggregation of the primary proteins of the lens, the crystallins. Human ?D-crystallin (H?D-Crys) is a major ?-crystallin in the nucleus of the human lens. We report here analysis of UVR-induced damage to H?D-Crys in vitro. Irradiation of solutions of recombinant H?D-Crys with UVA/UVB light produced a rise in solution turbidity due to polymerization of the monomeric crystallins into higher molecular weight aggregates. A significant fraction of this polymerized protein was covalently linked. Photoaggregation of H?D-Crys required oxygen and its rate was protein concentration and UVR dose dependent. To investigate the potential roles of individual tryptophan residues in photoaggregation, triple W:F mutants of H?D-Crys were irradiated. Surprisingly, despite reducing UVR absorbing capacity, multiple W:F H?D-Crys mutant proteins photoaggregated more quickly and extensively than wild type. The results reported here are consistent with previous studies that postulated that an energy transfer mechanism between the highly conserved pairs of tryptophan residues in H?D-Crys could be protective against UVR-induced photodamage.

Schafheimer, Nathaniel; King, Jonathan

2013-01-01

5

Preparation of inorganic crystalline compounds induced by ionizing, UV and laser radiations  

NASA Astrophysics Data System (ADS)

Results on preparation of nickel, zinc, yttrium, aluminum and cobalt oxides, zinc peroxide and hydroxide, yttrium and lutetium aluminum garnets and cobalt(II) aluminate via irradiation of aqueous solutions containing soluble metal salts and radical scavengers (formate anion or propan-2-ol) are summarized in this paper. Various physico-chemical and structural properties of prepared compounds (e.g. crystallinity, specific surface area, particle size) are also reported. All used variants of radiation method are rather convenient and simple, and yield nano-scale powder materials with interesting characteristics. Prepared materials generally have high chemical purity, high specific surface area and narrow distribution of particle size (ranging in tens of nm). Generally, accelerated electrons, gamma, and UV radiation yield materials with comparable properties and structural characteristics, but UV-radiation seems to be the most convenient for preparation of intricate compounds such as synthetic garnets and spinels, while ionizing radiation is better for preparation of compounds doped with foreign ions. Among discussed compounds, only zinc oxide, peroxide and hydroxide were prepared directly via irradiation. For preparation of other crystalline oxidic compounds, mild heat treatment of amorphous or weakly crystalline solid phase was necessary.

?uba, Václav; Pavelková, Tereza; Bárta, Jan; Gbur, Tomáš; Vlk, Martin; Zavadilová, Alena; Indrei, Jakub; Do?ekalová, Zuzana; Pospíšil, Milan; Mú?ka, Viliam

2012-09-01

6

Laser-induced crystalline optical waveguide in glass fiber format.  

PubMed

We report on the first fabrication of a glass fiber based laser-induced crystalline waveguide. The glass and crystal are based on the stoichiometric composition of (La,Yb)BGeO(5). A laser induced waveguide has been fabricated on the surface of a ribbon glass fiber using milliwatt-level continuous wave UV laser radiation at a fast scanning speed. Evidence of crystallinity in the created structure was observed using micro-Raman spectroscopy and scanning electron microscopy. Preliminary investigations on the waveguiding behavior and the nonlinear performance in the crystalline waveguide are reported. PMID:23262917

Feng, Xian; Shi, Jindan; Huang, Chung-Che; Horak, Peter; Teh, Peh Siong; Alam, Shaif-ul; Ibsen, Morten; Loh, Wei H

2012-12-10

7

Light-induced liquid crystallinity.  

PubMed

Liquid crystals are traditionally classified as thermotropic, lyotropic or polymeric, based on the stimulus that governs the organization and order of the molecular system. The most widely known and applied class of liquid crystals are a subset of thermotropic liquid crystals known as calamitic, in which adding heat can result in phase transitions from or into the nematic, cholesteric and smectic mesophases. Photoresponsive liquid-crystal materials and mixtures can undergo isothermal phase transitions if light affects the order parameter of the system within a mesophase sufficiently. In nearly all previous examinations, light exposure of photoresponsive liquid-crystal materials and mixtures resulted in order-decreasing photo-induced isothermal phase transitions. Under specialized conditions, an increase in order with light exposure has been reported, despite the tendency of the photoresponsive liquid-crystal system to reduce order in the exposed state. A direct, photo-induced transition from the isotropic to the nematic phase has been observed in a mixture of spiropyran molecules and a nematic liquid crystal. Here we report a class of naphthopyran-based materials that exhibit photo-induced conformational changes in molecular structure capable of yielding order-increasing phase transitions. Appropriate functionalization of the naphthopyran molecules leads to an exceedingly large order parameter in the open form, which results in a clear to strongly absorbing dichroic state. The increase in order with light exposure has profound implications in optics, photonics, lasing and displays and will merit further consideration for applications in solar energy harvesting. The large, photo-induced dichroism exhibited by the material system has been long sought in ophthalmic applications such as photochromic and polarized variable transmission sunglasses. PMID:22596158

Kosa, Tamas; Sukhomlinova, Ludmila; Su, Linli; Taheri, Bahman; White, Timothy J; Bunning, Timothy J

2012-05-17

8

The influence of crystallinity on radiation stability of UHMWPE  

NASA Astrophysics Data System (ADS)

The influence of ionizing radiation on ultra high molecular weight polyethylene (UHMWPE) was studied using EPR spectroscopy and GC. Two samples of various degree of crystallinity, 85% and 53%, were investigated upon exposure to electron beam. In this study it was found that radicals generated following irradiation decay much faster in amorphous than in crystalline phase. The primary product generated in both phases is second ordered alkyl radical. EPR spectra detected for the sample containing 85% crystalline regions revealed a quintet of hyperfine splitting about 2.28 mT and the signal was tentatively assigned to the product of ?-fragmentation. The radiation yield of hydrogen for two studied samples of various crystallinity was similar.

Kornacka, Ewa Maria; Przybytniak, Gra?yna; ?wi?szkowski, Wojciech

2013-03-01

9

Radiation-induced crystallinity changes in linear polyethylene: Long-term aging effects in pressure-crystallized ultra-high molecular weight polymer  

Microsoft Academic Search

It has been shown previously that linear polyethylenes undergo increases in crystallinity and peak melting temperature after irradiation, the magnitude of the effects being dependent upon the dose and the molecular weight of the polymer. The crystallinity was also found to increase with time after irradiation (aging) up to 112 months, although peak melting temperature declined slowly with aging time.

S. K. Bhateja; S. M. Yarbrough; E. H. Andrews

1990-01-01

10

Locating microearthquakes induced by hydraulic fracturing in crystalline rock  

Microsoft Academic Search

Microearthquakes induced by hydraulic fracturing in crystalline rock at a depth of 3.5 km were located with a precision of better than 30 m to obtain information about the geometry and dimensions of the fracture system produced. The induced microseismicity was monitored by a network of five vorehole seismic stations; a total of about 800 induced events were reliably located

Leigh House

1987-01-01

11

The radiation damage of crystalline silicon PN diode in tritium beta-voltaic battery.  

PubMed

A tritium beta-voltaic battery using a crystalline silicon convertor composed of (100)Si/SiO2/Si3N4 film degrades remarkably with radiation from a high intensity titanium tritide film. Simulation and experiments were carried out to investigate the main factor causing the degradation. The radiation damages mainly comes from the x-ray emitted from the titanium tritide film and beta particle can relieve the damages. The x-ray radiation induced positive charges in the SiO2 film destroying the output property of the PN diode with the induction of an electric field. PMID:24751350

Lei, Yisong; Yang, Yuqing; Liu, Yebing; Li, Hao; Wang, Guanquan; Hu, Rui; Xiong, Xiaoling; Luo, Shunzhong

2014-08-01

12

Radiation damage and minority carrier lifetime in crystalline silicon  

NASA Astrophysics Data System (ADS)

The lifetime of the minority carriers in p and n type crystalline silicon was measured with 1 MeV pulsed electron beam. Silicon samples were exposed to different fluences of 1 and 6 MeV electron, 14 MeV neutrons, thermal neutrons and 60Co gamma rays and the value of the radiation damage coefficient for each sample was estimated by monitoring variations in the minority carrier lifetime with radiation fluence. It is found that 14 MeV neutrons can be effectively used in reducing the lifetime of minority carriers in silicon and therefore have potential in controlling parameters of semiconductor devices.

Bhoraskar, V. N.; Dhole, S. D.; Singh, Surjit; Jahagirdar, S. M.; Srinivas, K. S.

1991-11-01

13

Radiation induced recombination processes in AIN ceramics  

NASA Astrophysics Data System (ADS)

Luminescence processes are studied for aluminum nitride, AlN, ceramics after exposure to ionizing radiation and ultraviolet radiation (UVR) using the methods of photoluminescence (PL), optically stimulated luminescence (OSL) and thermoluminescence (TL). The luminescence processes are explained in terms of radiation-induced charge transfer and radiative recombination of the donor-acceptor pairs, based on oxygen-related defects of the AlN crystalline lattice. The comparative effects of the two types of radiation, the efficiency of TL and OSL and the optimal sintering procedure of the ceramics are discussed for an AlN ceramic proposed for potential application in dosimetry.

Trinkler, L.; Berzina, B.

2001-10-01

14

Annealing of nanoindentation-induced high pressure crystalline phases created in crystalline and amorphous silicon  

Microsoft Academic Search

Thermally induced phase transformation of Si-III\\/Si-XII zones formed by nanoindentation has been studied during low temperature (200crystalline (c-Si) and amorphous silicon (a-Si) to study the zone size and starting

S. Ruffell; B. Haberl; S. Koenig; J. E. Bradby; J. S. Williams

2009-01-01

15

Radiation-induced gliomas  

PubMed Central

Radiation-induced gliomas represent a relatively rare but well-characterized entity in the neuro-oncologic literature. Extensive retrospective cohort data in pediatric populations after therapeutic intracranial radiation show a clearly increased risk in glioma incidence that is both patient age- and radiation dose/volume-dependent. Data in adults are more limited but show heightened risk in certain groups exposed to radiation. In both populations, there is no evidence linking increased risk associated with routine exposure to diagnostic radiation. At the molecular level, recent studies have found distinct genetic differences between radiation-induced gliomas and their spontaneously-occurring counterparts. Clinically, there is understandable reluctance on the part of clinicians to re-treat patients due to concern for cumulative neurotoxicity. However, available data suggest that aggressive intervention can lead to improved outcomes in patients with radiation-induced gliomas.

Prasad, Gautam; Haas-Kogan, Daphne A.

2013-01-01

16

[Radiation induced side effects].  

PubMed

More than half of all people with cancer are treated with radiation therapy. Over the last decade the technical advances, both in therapy beam precision and imaging, have greatly improved the therapeutic ratio and accuracy of modern radiotherapy. However, damaging healthy tissues near the tumor leads to radiation induced injury that develops immediately and continue to progress long after exposure to radiation. Recently dramatic advances have been made in understanding the determinant of tissue response to radiation exposure. PMID:22641879

Henni, Mehdi; Ali, David

2012-04-01

17

Combining optical coherence tomography with acoustic radiation force for depth-dependent biomechanics of crystalline lens  

NASA Astrophysics Data System (ADS)

Noninvasively probing the biomechanical properties of crystalline lens has been challenging due to its unique features such as location inside the eye and being optically and ultrasonically transparent. Here we introduce a method of relying on the spectral analysis of the lens surface response to a mechanical stimulation for the depthdependent assessment of lens biomechanical properties. In this method, acoustic radiation force (ARF) is used to remotely induce the deformation on the surface of the crystalline lens, and a phase-sensitive optical coherence tomography (PhS-OCT) system, co-focused with ARF, utilized to monitor the localized temporal response of ARFinduced deformations on the lens surface. The dominant frequency from the amplitude spectra of the surface response is obtained as the indicator of the depthwise elasticity distribution. Pilot experiments were performed on tissue-mimicking layered phantoms and ex vivo porcine crystalline lens. Results indicate that the frequency response of the sample surface is contributed by the mechanical properties of layers located at different depths and the depthdependent elastic properties can be revealed from the amplitude spectrum. Further study will be focused on combining the experimental measurements with theoretical model and inverse numerical method for depth-resolved elastography of the crystalline lens.

Wang, Shang; Aglyamov, Salavat; Karpiouk, Andrei; Li, Jiasong; Emelianov, Stanislav; Manns, Fabrice; Larin, Kirill V.

2014-03-01

18

Radiation-induced pneumothorax  

SciTech Connect

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.

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

1983-01-01

19

Growth Induced Magnetic Anisotropy in Crystalline and Amorphous Thin Films  

SciTech Connect

OAK B204 Growth Induced Magnetic Anisotropy in Crystalline and Amorphous Thin Films. The work in the past 6 months has involved three areas of magnetic thin films: (1) amorphous rare earth-transition metal alloys, (2) epitaxial Co-Pt and hTi-Pt alloy thin films, and (3) collaborative work on heat capacity measurements of magnetic thin films, including nanoparticles and CMR materials.

Hellman, Frances

1998-10-03

20

Gravitational radiation from crystalline color-superconducting hybrid stars  

SciTech Connect

The interiors of high mass compact (neutron) stars may contain deconfined quark matter in a crystalline color-superconducting (CCS) state. On a basis of microscopic nuclear and quark matter equations of states we explore the internal structure of such stars in general relativity. We find that their stable sequence harbors CCS quark cores with masses M{sub core}{<=}(0.78-0.82)M{sub {center_dot}} and radii R{sub core}{<=}7 km. The CCS quark matter can support nonaxisymmetric deformations, because of its finite shear modulus, and can generate gravitational radiation at twice the rotation frequency of the star. Assuming that the CCS core is maximally strained we compute the maximal quadrupole moment it can sustain. The characteristic strain of gravitational wave emission h{sub 0} predicted by our models are compared to the upper limits obtained by the LIGO and GEO 600 detectors. The upper limits are consistent with the breaking strain of CCS matter {sigma}{<=}10{sup -4} and large pairing gaps {delta}{approx}50 MeV, or, alternatively, with {sigma}{approx}10{sup -3} and small pairing gaps {delta}{approx}15 MeV. An observationally determined value of the characteristic strain h{sub 0} can pin down the product {sigma}{delta}{sup 2}. On the theoretical side a better understanding of the breaking strain of CCS matter will be needed to predict reliably the level of the deformation of CCS quark core from first principles.

Knippel, Bettina; Sedrakian, Armen [Institute for Theoretical Physics, Goethe-University, D-60438 Frankfurt am Main (Germany)

2009-04-15

21

Decreased chaperone activity of ?-crystallin in selenite cataract may result from selenite-induced aggregation  

Microsoft Academic Search

Purpose To investigate the role of chaperone activity of ?-crystallin in selenite-induced cataract formation.Methods Selenite cataract was induced in Sprague–Dawley rats by five subcutaneous injections of sodium selenite over a 20-day period starting at 8–10 days postpartum. ?-Crystallin was separated from the rat lenses by size-exclusion chromatography. Bovine ?L-crystallin and ?L-crystallin were isolated for studies in vitro, and for the

H Yan; J J Harding; Y N Hui; M Y Li

2003-01-01

22

[Radiation induced carcinogenesis].  

PubMed

Intense research after Hiroshima and Nagasaki atomic bomb (A-bomb) tragedy and Chernobyl nuclear plant accident revealed that ionizing radiation (IR) more than 100 mSv induces cancers that are indistinguishable from sporadic tumors. It remains controversial whether low dose IR (less than 100 mSv) is oncogenic or not. Among IR-induced malignancies, leukemia (A-bomb) and thyroid cancers (Chernobyl), in which chimeric(fusion) oncogenes formed by chromosome translocations play a critical role, develop with relatively short latency. All other cancers develop after long latency. Age-related epigenetic changes, as well as additional genetic alterations, would contribute to IR-induced carcinogenesis. PMID:22514919

Inaba, Toshiya

2012-03-01

23

Radiation-Induced Bioradicals  

NASA Astrophysics Data System (ADS)

This chapter represents the second part of a review in which the production and application of radiation-induced radicals in biological matter are discussed. In part one the general aspects of the four stages (physical, physicochemical, chemical and biological) of interaction of radiation with matter in general and biological matter in particular, were discussed. Here an overview is presented of modem technologies and theoretical methods available for studying these radiation effects. The relevance is highlighted of electron paramagnetic resonance spectroscopy and quantum chemical calculations with respect to obtaining structural information on bioradicals, and a survey is given of the research studies in this field. We also discuss some basic aspects of modem accelerator technologies which can be used for creating radicals and we conclude with an overview of applications of radiation processing in biology and related fields such as biomedical and environmental engineering, food technology, medicine and pharmacy.

Lahorte, Philippe; Mondelaers, Wim

24

Light induced changes in the amorphous--crystalline silicon heterointerface  

NASA Astrophysics Data System (ADS)

The photostability of the amorphous--crystalline silicon heterointerface is investigated. It is revealed that the metastability of hydrogenated amorphous silicon (a-Si:H) causes significant light induced changes in the heterointerface. Unlike bulk a-Si:H, the photostability of the heterointerface is not controlled by the microstructural properties of a-Si:H but rather by the initial heterointerface properties. Interfaces that initially have low interface defect density show the greatest degradation while those that initially have high interface defect density actually show light-induced improvement. It is shown that the degree of light induced change in the interface defect density is linearly proportional to the natural logarithm of the initial interface defect density. Further, it is revealed that the kinetics of light-induced change in the heterointerface defect density can be faster or slower than light-induced changes in bulk a-Si:H films depending on the initial properties of the heterointerface. Light soaking measurements on heterointerfaces with doped a-Si:H films reveal that interface defect density of these structures improves with light soaking. It is proposed that this is caused by a combination of the high initial interface defect density of samples using doped a-Si:H films and reduced generation of defects near the heterointerface due to the enhanced field effect provided by the doped films.

Mahtani, Pratish; Varache, Renaud; Jovet, Bastien; Longeaud, Christophe; Kleider, Jean-Paul; Kherani, Nazir P.

2013-09-01

25

[Radiation-induced neuropathy].  

PubMed

Radiation-induced neuropathy is commonly observed among oncological patients. Radiation can affect the nervous tissue directly or indirectly by inducing vasculopathy or dysfunction of internal organs. Symptoms may be mild and reversible (e.g., pain, nausea, vomiting, fever, drowsiness, fatigue, paresthesia) or life-threatening (cerebral oedema, increased intracranial pressure, seizures). Such complications are clinically divided into peripheral (plexopathies, neuropathies of spinal and cranial nerves) and central neuropathy (myelopathy, encephalopathy, cognitive impairment). The degree of neuronal damages primarily depends on the total and fractional radiation dose and applied therapeutic methods. The conformal and megavoltage radiotherapy seems to be the safeties ones. Diagnostic protocol includes physical examination, imaging (in particular magnetic resonance), electromyography, nerve conduction study and sometimes histological examination. Prevention and early detection of neurological complications are necessary in order to prevent a permanent dysfunction of the nervous system. Presently their treatment is mostly symptomatic, but in same cases a surgical intervention is required. An experimental and clinical data indicates some effectiveness of different neuroprotective agents (e.g. anticoagulants, vitamin E, hyperbaric oxygen, pentoxifylline, bevacizumab, methylphenidate, donepezil), which should be administered before and/or during radiotherapy. PMID:24490474

Kolak, Agnieszka; Staros?awska, Elzbieta; Kieszko, Dariusz; Cisek, Pawe?; Patyra, Krzysztof Ireneusz; Surdyka, Dariusz; Dobrzy?ska-Rutkowska, Aneta; ?opacka-Szatan, Karolina; Burdan, Franciszek

2013-12-01

26

Radiation-Induced Effects on Microstructure  

SciTech Connect

Irradiation of materials with particles that are sufficiently energetic to create atomic displacements can induce significant microstructural alteration, ranging from crystalline-to-amorphous phase transitions to the generation of large concentrations of point defect or solute aggregates in crystalline lattices. These microstructural changes typically cause significant changes in the physical and mechanical properties of the irradiated material. A variety of advanced microstructural characterization tools are available to examine the microstructural changes induced by particle irradiation, including electron microscopy, atom probe field ion microscopy, X-ray scattering and spectrometry, Rutherford backscattering spectrometry, nuclear reaction analysis, and neutron scattering and spectrometry. Numerous reviews, which summarize the microstructural changes in materials associated with electron and heavy ion or neutron irradiation, have been published. These reviews have focused on pure metals as well as model alloys, steels, and ceramic materials. In this chapter, the commonly observed defect cluster morphologies produced by particle irradiation are summarized and an overview is presented on some of the key physical parameters that have a major influence on microstructural evolution of irradiated materials. The relationship between microstructural changes and evolution of physical and mechanical properties is then summarized, with particular emphasis on eight key radiation-induced property degradation phenomena. Typical examples of irradiated microstructures of metals and ceramic materials are presented. Radiation-induced changes in the microstructure of organic materials such as polymers are not discussed in this overview.

Zinkle, Steven J [ORNL

2012-01-01

27

Crystalline undulator radiation of microbunched beams taking into account the medium polarization  

NASA Astrophysics Data System (ADS)

Analytical and numerical results are obtained on the angular and spectral distributions of the number of photons as well as on the total number of the photons of the coherent X-ray crystalline undulator radiation (CXCUR) produced by microbunched beams passing through crystalline undulators (CU). These results show that one can use CXCUR for study of the microbunching process in XFELs and for production of additional monochromatic intense beams.

Gevorgian, L. A.; Ispirian, K. A.; Shamamian, A. H.

2013-08-01

28

Induced seismicity in crystalline basement: Understanding the reasons  

NASA Astrophysics Data System (ADS)

In recent years, cases of induced seismicity have been reported for geothermal wells in aseismic regions. The use of geothermal energy naturally influences the reservoir as heat and water are withdrawn. However, most geothermal plants reinject the water so that pressure levels within the reservoir remain more or less stable. Despite this and despite low injection pressures, some of these reinjecting plants experience induced seismicity. One example is the well Unterhaching Gt2, close to Munich, Germany. Here, the reservoir is an approximately 500 m thick karstified limestone layer of the Upper Jurassic, in which extraction and reinjection take place. Flow rates of more than 100 l/s have been established with reinjection pressures below 10 bar. Nevertheless, induced seismicity occurs. Most of the events are below 1.0 but some reach up to 2.4 on the Richter scale. Due to their location, they can without any doubt be attributed to the reinjection process. However, the origin of the quakes is not within the reservoir but located in the crystalline basement. As the reinjection well cuts through a steeply inclined fault, a hydraulic connection between reservoir, borehole and basement is given if a hydraulically open fault is assumed. So far, it was impossible to find a correlation between the occurrence of induced seismicity and operating parameters of the geothermal plant like flow rate, injection pressure, or temperature. Therefore, thermo-hydraulic-mechanical numerical models of the subsurface have been developed to understand the interaction between different parameters and to possibly identify critical thresholds for the initiation of induced seismicity. Due to the large scale of the model, several kilometers in each direction, an equivalent porosity approach has been chosen for the hydraulic modeling of the karstic limestone layer. Flow within in the fault is also described by Darcy's law as the fault is not assumed to be a surface but a volume. This assumption is based on the analysis of seismic data of this region, which indicate a zone of damaged rock several tens of meters in diameter. Because of this approach to model the hydraulics, the pore pressure within the fault will most likely be the determining factor for the onset of induced seismicity. Therefore, it is of high interest to analyse the influence of the operating parameters of the geothermal plant on this parameter.

Schumacher, Sandra

2014-05-01

29

Real-time WAXS study of induced orientation in a liquid crystalline polyester under the influence of a magnetic field  

Microsoft Academic Search

The in situ variation of induced orientation within a liquid crystalline polyester under the influence of a magnetic field was investigated during heat treatment, by means of wide-angle X-ray scattering (WAXS) using synchrotron radiation. The kinetics of molecular orientation, both from the melt and from the solid state, is analyzed in a wide temperature range (T=190–260°C) in terms of the

F Ania; A Flores; H. R Kricheldorf; F. J Baltá-Calleja

2003-01-01

30

Dependencia do grau de cristalinidade com a graftizacao induzida por radiacao gama da N,N(sup ') - dimetilacrilamida em polietileno. (Dependence of crystallinity degree with induced grafting by gamma radiation of N,N(sup ')-dimethyl acrylamide).  

National Technical Information Service (NTIS)

N,N' -dimethyl acrylamide (DMAA) graft copolymerization onto polyethylene films was carried out, using a organic solvent as a reaction medium and gamma rays from a (sup 60) Co source for surface activation. Thermal analysis revealed the crystallinity and ...

A. A. A. Queiroz O. Z. Higa E. R. Barrak I. Giolito

1991-01-01

31

Radiation-induced damage studies of energetic materials  

Microsoft Academic Search

We present studies of synchrotron radiation-induced decomposition of PETN and TATB under conditions of high pressure, high temperature, and crystalline orientation. We have found that the decomposition rate varies dramatically under all three of these variables. The experiments were performed using white beam synchrotron radiation at the 16 BM-B and 16 BM-D sectors of the HP-CAT beamline at the Advanced

Michael Pravica; Hubertus Giefers; Zachary Quine; Edward Romano; Sean Bajar; Brian Yulga; Wenge Yang; Hans Peter Liermann; Daniel Hooks

2007-01-01

32

Fracture-Induced Thermal Decomposition in Brittle Crystalline Solids.  

National Technical Information Service (NTIS)

An experimental study has been made of the thermal decomposition produced by the release of elastic strain energy when a fast cleavage crack runs through a brittle crystalline solid. The amounts of decomposition are measured for cleavages in crystals of c...

J. Soria-Ruiz P. G. Fox

1970-01-01

33

Radiation-induced intracranial fibrochondrosarcoma.  

PubMed

A 50-year-old patient developed a left temporal fibrochondrosarcoma 27 years after radiation therapy for a suspected pituitary adenoma. The long latency between the irradiation and the development of the sarcoma and the histological nature of the tumour are unusual features for a malignant radiation-induced intracranial tumour. The histogenesis of fibrochondrosarcoma of the brain is discussed. PMID:3772411

Pagès, A; Pagès, M; Ramos, J; Bénézech, J

1986-10-01

34

Radiation-induced enteropathy  

Microsoft Academic Search

The incidence of chronic radiation enteritis appears to have risen in recent years due to the increasing utilization of radiotherapy for abdominal and pelvic malignancies. The etiology, pathogenesis, and management of radiation enteritis are discussed. Two case reports exemplify the progressive nature of the disease. Case 1 demonstrates the classical picture of multiple exacerbations and remissions of partial small bowel

M. E. Sher; J. Bauer

1990-01-01

35

Protection of Retina by ?B Crystallin in Sodium Iodate Induced Retinal Degeneration  

PubMed Central

Age-related macular degeneration (AMD) is a leading cause of blindness in the developed world. The retinal pigment epithelium (RPE) is a critical site of pathology in AMD and ?B crystallin expression is increased in RPE and associated drusen in AMD. The purpose of this study was to investigate the role of ?B crystallin in sodium iodate (NaIO3)-induced retinal degeneration, a model of AMD in which the primary site of pathology is the RPE. Dose dependent effects of intravenous NaIO3 (20-70 mg/kg) on development of retinal degeneration (fundus photography) and RPE and retinal neuronal loss (histology) were determined in wild type and ?B crystallin knockout mice. Absence of ?B crystallin augmented retinal degeneration in low dose (20 mg/kg) NaIO3-treated mice and increased retinal cell apoptosis which was mainly localized to the RPE layer. Generation of reactive oxygen species (ROS) was observed with NaIO3 in mouse and human RPE which increased further after ?B crystallin knockout or siRNA knockdown, respectively. NaIO3 upregulated AKT phosphorylation and peroxisome proliferator–activator receptor–? (PPAR?) which was suppressed after ?B crystallin siRNA knockdown. Further, PPAR? ligand inhibited NaIO3-induced ROS generation. Our data suggest that ?B crystallin plays a critical role in protection of NaIO3-induced oxidative stress and retinal degeneration in part through upregulation of AKT phosphorylation and PPAR? expression.

Zhou, Peng; Kannan, Ram; Spee, Christine; Sreekumar, Parameswaran G.; Dou, Guorui; Hinton, David R.

2014-01-01

36

Disorder-induced localization in crystalline phase-change materials  

Microsoft Academic Search

Localization of charge carriers in crystalline solids has been the subject of numerous investigations over more than half a century. Materials that show a metal-insulator transition without a structural change are therefore of interest. Mechanisms leading to metal-insulator transition include electron correlation (Mott transition) or disorder (Anderson localization), but a clear distinction is difficult. Here we report on a metal-insulator

T. Siegrist; P. Jost; H. Volker; M. Woda; P. Merkelbach; C. Schlockermann; M. Wuttig

2011-01-01

37

Crystalline polymorphism induced by charge regulation in ionic membranes  

PubMed Central

The crystallization of molecules with polar and hydrophobic groups, such as ionic amphiphiles and proteins, is of paramount importance in biology and biotechnology. By coassembling dilysine (+2) and carboxylate (–1) amphiphiles of various tail lengths into bilayer membranes at different pH values, we show that the 2D crystallization process in amphiphile membranes can be controlled by modifying the competition of long-range and short-range interactions among the polar and the hydrophobic groups. The pH and the hydrophobic tail length modify the intermolecular packing and the symmetry of their crystalline phase. For hydrophobic tail lengths of 14 carbons (C14), we observe the coassembly into crystalline bilayers with hexagonal molecular ordering via in situ small- and wide-angle X-ray scattering. As the tail length increases, the hexagonal lattice spacing decreases due to an increase in van der Waals interactions, as demonstrated by atomistic molecular dynamics simulations. For C16 and C18 we observe a reentrant crystalline phase transition sequence, hexagonal–rectangular-C–rectangular-P–rectangular-C–hexagonal, as the solution pH is increased from 3 to 10.5. The stability of the rectangular phases, which maximize tail packing, increases with increasing tail length. As a result, for very long tails (C22), the possibility of observing packing symmetries other than rectangular-C phases diminishes. Our work demonstrates that it is possible to systematically exchange chemical and mechanical energy by changing the solution pH value within a range of physiological conditions at room temperature in bilayers of molecules with ionizable groups.

Leung, Cheuk-Yui; Palmer, Liam C.; Kewalramani, Sumit; Qiao, Baofu; Stupp, Samuel I.; Olvera de la Cruz, Monica; Bedzyk, Michael J.

2013-01-01

38

Crystalline polymorphism induced by charge regulation in ionic membranes.  

PubMed

The crystallization of molecules with polar and hydrophobic groups, such as ionic amphiphiles and proteins, is of paramount importance in biology and biotechnology. By coassembling dilysine (+2) and carboxylate (-1) amphiphiles of various tail lengths into bilayer membranes at different pH values, we show that the 2D crystallization process in amphiphile membranes can be controlled by modifying the competition of long-range and short-range interactions among the polar and the hydrophobic groups. The pH and the hydrophobic tail length modify the intermolecular packing and the symmetry of their crystalline phase. For hydrophobic tail lengths of 14 carbons (C14), we observe the coassembly into crystalline bilayers with hexagonal molecular ordering via in situ small- and wide-angle X-ray scattering. As the tail length increases, the hexagonal lattice spacing decreases due to an increase in van der Waals interactions, as demonstrated by atomistic molecular dynamics simulations. For C16 and C18 we observe a reentrant crystalline phase transition sequence, hexagonal-rectangular-C-rectangular-P-rectangular-C-hexagonal, as the solution pH is increased from 3 to 10.5. The stability of the rectangular phases, which maximize tail packing, increases with increasing tail length. As a result, for very long tails (C22), the possibility of observing packing symmetries other than rectangular-C phases diminishes. Our work demonstrates that it is possible to systematically exchange chemical and mechanical energy by changing the solution pH value within a range of physiological conditions at room temperature in bilayers of molecules with ionizable groups. PMID:24065818

Leung, Cheuk-Yui; Palmer, Liam C; Kewalramani, Sumit; Qiao, Baofu; Stupp, Samuel I; Olvera de la Cruz, Monica; Bedzyk, Michael J

2013-10-01

39

Radiation-induced damage studies of energetic materials.  

NASA Astrophysics Data System (ADS)

We present studies of synchrotron radiation-induced decomposition of PETN and TATB under conditions of high pressure, high temperature, and crystalline orientation. We have found that the decomposition rate varies dramatically under all three of these variables. The experiments were performed using white beam synchrotron radiation at the 16 BM-B and 16 BM-D sectors of the HP-CAT beamline at the Advanced Photon Source. Diffraction line intensities were measured as a function of time using energy-dispersive methods and angular-dispersive methods TATB showed dramatic slowing of the decomposition rate with pressure implying a positive activation volume of the activated complex whereas PETN showed little change in decomposition rate with pressure. Increased temperature increased the radiation-induced decomposition rate of TATB. Finally, we found dramatic differences in the radiation-induced decomposition rate for single crystals of explosives depending upon their orientation relative to the polarized x-ray beam.

Pravica, Michael; Giefers, Hubertus; Quine, Zachary; Romano, Edward; Bajar, Sean; Yulga, Brian; Yang, Wenge; Liermann, Hans Peter; Hooks, Daniel

2007-06-01

40

Analysis of the Cytoprotective Role of ?-Crystallins in Cell Survival and Implication of the ?A-Crystallin C-Terminal Extension Domain in Preventing Bax-Induced Apoptosis  

PubMed Central

?-Crystallins, initially described as the major structural proteins of the lens, belong to the small heat shock protein family. Apart from their function as chaperones, ?-crystallins are involved in the regulation of intracellular apoptotic signals. ?A- and ?B-crystallins have been shown to interfere with the mitochondrial apoptotic pathway triggering Bax pro-apoptotic activity and downstream activation of effector caspases. Differential regulation of ?-crystallins has been observed in several eye diseases such as age-related macular degeneration and stress-induced and inherited retinal degenerations. Although the function of ?-crystallins in healthy and diseased retina remains poorly understood, their altered expression in pathological conditions argue in favor of a role in cellular defensive response. In the Rpe65?/? mouse model of Leber's congenital amaurosis, we previously observed decreased expression of ?A- and ?B-crystallins during disease progression, which was correlated with Bax pro-death activity and photoreceptor apoptosis. In the present study, we demonstrated that ?-crystallins interacted with pro-apoptotic Bax and displayed cytoprotective action against Bax-triggered apoptosis, as assessed by TUNEL and caspase assays. We further observed in staurosporine-treated photoreceptor-like 661W cells stably overexpressing ?A- or ?B-crystallin that Bax-dependent apoptosis and caspase activation were inhibited. Finally, we reported that the C-terminal extension domain of ?A-crystallin was sufficient to provide protection against Bax-triggered apoptosis. Altogether, these data suggest that ?-crystallins interfere with Bax-induced apoptosis in several cell types, including the cone-derived 661W cells. They further suggest that ?A-crystallin-derived peptides might be sufficient to promote cytoprotective action in response to apoptotic cell death.

Hamann, Severine; Metrailler, Sylviane; Schorderet, Daniel F.; Cottet, Sandra

2013-01-01

41

Radiation stability test on multiphase glass ceramic and crystalline ceramic waste forms  

NASA Astrophysics Data System (ADS)

A radiation stability study was performed on glass ceramic and crystalline ceramic waste forms. These materials are candidate host materials for immobilizing alkali/alkaline earth (Cs/Sr-CS) + lanthanide (LN) + transition metal (TM) fission product waste streams from nuclear fuel reprocessing. In this study, glass ceramics were fabricated using a borosilicate glass as a matrix in which to incorporate CS/LN/TM combined waste streams. The major phases in these multiphase materials are powellite, oxyaptite, pollucite, celsian, and durable residual glass phases. Al2O3 and TiO2 were combined with these waste components to produce multiphase crystalline ceramics containing hollandite-type phases, perovskites, pyrochlores and other minor metal titanate phases.

Tang, Ming; Kossoy, Anna; Jarvinen, Gordon; Crum, Jarrod; Turo, Laura; Riley, Brian; Brinkman, Kyle; Fox, Kevin; Amoroso, Jake; Marra, James

2014-05-01

42

Radiation-induced peritoneal mesothelioma  

Microsoft Academic Search

A case report of a patient who developed peritoneal mesothelioma 7 years after internal and external irradiation for carcinoma of the cervix is reported. No previous reports of induction of this tumor by irradiation have been found. The subject of radiation-induced tumors and peritoneal mesothelioma is briefly discussed.

Terence L. Babcock; Darryl H. Powell; Roger S. Bothwell

1976-01-01

43

Radiation–Induced Haemorrhagic Cystitis  

Microsoft Academic Search

Objectives: In this article we review the literature concerning the frequency and management of severe haemorrhagic radiation–induced cystitis.Methods: A Medline search was performed from 1966 to 1999 for articles in English. A total of 309 references were found. Abstracts and complete articles were reviewed.Results: Severe haemorrhagic cystitis following radiotherapy remains a relatively rare event. However, the fact that it is

Jeremy P. Crew; Catherine R. Jephcott; John M. Reynard

2001-01-01

44

Radiation induced estane polymer crosslinking  

SciTech Connect

The exposure of polymeric materials to radiation has been known to induce the effects of crosslinking and degradation. The crosslinking phenomena comes about when two long chain polymers become linked together by a primary bond that extends the chain and increases the viscosity, molecular weight and the elastic modules of the polymer. This process has been observed in relatively short periods of time with fairly high doses of radiation, on the order of several megarads/hour. This paper address low dose exposure over long periods of time to determine what the radiation effects are on the polymeric binder material in PBX 9501. An experimental sample of binder material without explosives will be placed into a thermal and radiation field produced from a W-48 put mod 0. Another sample will be placed in a thermal environment without the radiation. The following is the test plan that was submitted to the Pantex process. The data presented here will be from the first few weeks of exposure and this test will be continued over the next few years. Subsequent data will hopefully be presented in the next compatibility and aging conference.

Fletcher, M. [Los Alamos National Lab., NM (United States); Foster, P. [Masson Hanger Pantex Plant, Amarillo, TX (United States)

1997-12-01

45

Femtosecond laser induced ablation of crystalline silicon upon double beam irradiation  

Microsoft Academic Search

Ultra-short pulsed laser radiation has been shown to be effective for precision materials processing. Advantages include the non-thermal nature of ablation process and short thermal penetration depth. These are ideal characteristics for precision microstructuring and controlled ablation. A crystalline silicon sample is subjected to two optically separated ultra-fast laser pulses of full width half maximum (FWHM) duration of about 80

Tae Y. Choi; David J. Hwang; Costas P. Grigoropoulos

2002-01-01

46

The ability of lens alpha crystallin to protect against heat-induced aggregation is age-dependent  

NASA Technical Reports Server (NTRS)

Alpha crystallin was prepared from newborn and aged bovine lenses. SDS-PAGE and tryptic peptide mapping demonstrated that both preparations contained only the alpha-A and alpha-B chains, with no significant contamination of other crystallins. Compared with alpha crystallin from the aged lens, alpha crystallin from the newborn lens was much more effective in the inhibition of beta L crystallin denaturation and precipitation induced in vitro by heat. Together, these results demonstrate that during the aging process, the alpha crystallins lose their ability to protect against protein denaturation, consistent with the hypothesis that the alpha crystallins play an important role in the maintenance of protein native structure in the intact lens.

Horwitz, J.; Emmons, T.; Takemoto, L.; Spooner, B. S. (Principal Investigator)

1992-01-01

47

Seeded growth induced amorphous to crystalline transformation of niobium oxide nanostructures  

NASA Astrophysics Data System (ADS)

A novel high-temperature synthesis of niobium oxide nanostructures has been developed through an amorphous intermediate that crystallizes into anisotropic crystalline structures through a complex mechanism of nucleation-dissolution-selective growth induced by seeded growth. The amorphous materials formed by the thermolysis of niobium oleate transformed into crystalline platelets, wires or bundled wires after the injection of additional niobium oleate at different temperatures. The temperature of the solution during injection of the additional precursor determined the morphology of the formed crystalline structure. The time- and temperature-dependent evolution of the niobium oxide nanostructures demonstrates that amorphous materials progressively turned to crystalline materials. We tuned the size of wires and platelets by the consecutive injection of the precursor solution into the reaction mixture under isothermal conditions. With the sequential injection of the precursor solution, we demonstrate that the anisotropic growth of individual nanowires occurs exclusively along the ends, without the formation of any new nuclei. A mechanism for the transformation of well-defined platelets from wires has been proposed and is due to the exclusive loss of mass at the ends of the wires while growth of the platelets initially occurs along the (001) direction which is then replaced by the (110) face.A novel high-temperature synthesis of niobium oxide nanostructures has been developed through an amorphous intermediate that crystallizes into anisotropic crystalline structures through a complex mechanism of nucleation-dissolution-selective growth induced by seeded growth. The amorphous materials formed by the thermolysis of niobium oleate transformed into crystalline platelets, wires or bundled wires after the injection of additional niobium oleate at different temperatures. The temperature of the solution during injection of the additional precursor determined the morphology of the formed crystalline structure. The time- and temperature-dependent evolution of the niobium oxide nanostructures demonstrates that amorphous materials progressively turned to crystalline materials. We tuned the size of wires and platelets by the consecutive injection of the precursor solution into the reaction mixture under isothermal conditions. With the sequential injection of the precursor solution, we demonstrate that the anisotropic growth of individual nanowires occurs exclusively along the ends, without the formation of any new nuclei. A mechanism for the transformation of well-defined platelets from wires has been proposed and is due to the exclusive loss of mass at the ends of the wires while growth of the platelets initially occurs along the (001) direction which is then replaced by the (110) face. Electronic supplementary information (ESI) available: Additional TEM images, XRD, TGA, and UV-Visible absorption spectra of niobium oxide nanostructures. See DOI: 10.1039/c2nr11803c

Jana, Subhra; Rioux, Robert M.

2012-02-01

48

Shock induced radiation from minerals  

NASA Technical Reports Server (NTRS)

Schmitt and Ahrens (1983) have concluded that the type of optical emission produced during shock compression was dependent upon phase changes taking place during shock compression. The present study is concerned with new observations of shock-induced optical radiation from Al2O3, MgO, NaCl, KCl, x-cut and fused SiO2, and LiF at various pressures up to 75 GPa. The experimental setup used in the study is similar to that employed by Schmitt and Ahrens. An Image Converter Camera with a three-frame plug-in unit was added to take two or three exposures of the radiation field during shock wave propagation through the sample, taking into account exposure times in the range from 50 to 500 nsec. The greybody emissions observed in LiF, which undergoes no phase transition, imply that localized heating and perhaps melting occurs in this material during shock deformation.

Schmitt, D.; Svendsen, B.; Ahrens, T. J.

1985-01-01

49

Radiation-induced leukemia: lessons from history.  

PubMed

Beginning in 1895, with the discovery of x-rays, alpha and beta radiation, uranium, radium, thorium, and polonium, the fascinating story of the beginning of knowledge concerning the existence of ionizing radiation unfolds. This brief history of radiation and leukemia is divided into two main parts: the first 50 years, which deals with the confusion regarding radiation effects and the failure to clearly recognize that exposure to ionizing radiation may induce leukemia. The second part focuses on the last 60 years, when the radiation induction of leukemia was accepted and some progress achieved in understanding the clinical and pathophysiological characteristics of radiation-induced leukemia. Particular attention in this is paid to the effects of radiation on the survivors of Hiroshima and Nagasaki. The discussion in this section also covers some concepts of radiation-induced cell damage and ruminations on unanswered questions. PMID:17336261

Finch, Stuart C

2007-03-01

50

Electrostatic-field-induced chain alignment of liquid crystalline copolyether TPP thin films  

Microsoft Academic Search

A liquid crystalline (LC) copolyether has been synthesized from 1-(4-hydroxy-4?-biphenyl)-2-(4-hydroxyphenyl)propane with 1,7-dibromoheptane and 1,11-dibromoundecane with a 50\\/50 (both in %) equal composition of the 7- and 11-methylene monomers [coTPP-7\\/11(5\\/5)]. A mono-domain with a homeotropic alignment can be induced by a thin film surface in the LC phase. When an electrostatic field is applied to the surface-induced mono-domains parallel to the

Fengchao Xie; Zhijun Hu; Jieping Liu; Xiaoniu Yang; Donghang Yan; Tianbai He; Ruqing Zheng; S. Z. D. Cheng; V. Percec

2001-01-01

51

Direct decoration of disclinations by solidification-induced band texture for a nematic side chain liquid crystalline polymer  

Microsoft Academic Search

For a nematic polymethacrylate side chain liquid crystalline polymer, g 154 N 298 I (°C), the solidification-induced band texture has been observed aligned along the disclination under a polarizing optical microscope, when the specimen was quenched from 280°C to room temperature. The decoration technique of solidification-induced band texture, which is usually reported for main chain liquid crystalline polymers, was then

Qincui Gu; Changcheng Wu; Shouxi Chen

2004-01-01

52

Radiation-induced leukemias in ankylosing spondylitis  

SciTech Connect

Three cases of leukemia occurred in patients with ankylosing spondylitis treated by radiotherapy. In each case, the leukemic process exhibited bizarre features suggesting that radiation is likely to induce atypical forms of leukemia possessing unusual attributes not shared by spontaneously developing leukemia. The likely distinctive aspects of radiation-induced leukemia are discussed.

Toolis, F. (Royal Infirmary, Edinburgh, UK); Potter, B.; Allan, N.C.; Langlands, A.O.

1981-10-01

53

Radiation-induced defect centers in glass ceramics  

SciTech Connect

Electron spin resonance (ESR) was used to characterize the radiation-induced defect centers in low-thermal-expansion glass ceramics, including two types of Zerodur and Astrositall. The observed ESR spectra can be associated with different types of defect centers: a Zn/sup +/ center, several types of oxygen hole centers (OHCs), an aluminum-oxygen hole center (Al-OHC), an Fe/sup 3 +/ center, Ti/sup 3 +/ and Zr/sup 3 +/ centers, and three types of As centers. An Sb/sup 4 +/ center, which is not observed in Zerodur, is tentatively identified in Astrositall. From the effect of crystallization on the observed defect concentrations in Zerodur and computer simulation of the spectral lines of some of the centers, we infer that among the nine defect centers observed in the Zerodurs, the As-associated centers are located in the glassy phase and/or at the interface between the glassy and crystalline phases, Zn/sup +/ and Al-OHC are in the crystalline phase, and the rest (including most of the OHCs) are in the glassy phase. Radiation-induced compaction in these materials appears to be related to the generation of OHCs in the glass phase.

Tsai, T.E.; Friebele, E.J.; Griscom, D.L.; Pannhorst, W.

1989-01-15

54

Radiation-induced gene responses  

SciTech Connect

In the process of identifying genes that are differentially regulated in cells exposed to ultraviolet radiation (UV), we identified a transcript that was repressed following the exposure of cells to a combination of UV and salicylate, a known inhibitor of NF-kappaB. Sequencing this band determined that it has identify to lactate dehydrogenase, and Northern blots confirmed the initial expression pattern. Analysis of the sequence of the LDH 5` region established the presence of NF-kappaB, Sp1, and two Ap-2 elements; two partial AP- 1; one partial RE, and two halves of E-UV elements were also found. Electromobility shift assays were then performed for the AP-1, NF- kappaB, and E-UV elements. These experiments revealed that binding to NF-kappaB was induced by UV but repressed with salicylic acid; UV did not affect AP-1 binding, but salicylic acid inhibited it alone or following UV exposure; and E-UV binding was repressed by UV, and salicylic acid had little effect. Since the binding of no single element correlated with the expression pattern of LDH, it is likely that multiple elements govern UV/salicylate-mediated expression.

Woloschak, G.E.; Paunesku, T.; Shearin-Jones, P.; Oryhon, J.

1996-12-31

55

Molecular insights into the progression of crystalline silica-induced pulmonary toxicity in rats.  

PubMed

Identification of molecular target(s) and mechanism(s) of silica-induced pulmonary toxicity is important for the intervention and/or prevention of diseases associated with exposure to silica. Rats were exposed to crystalline silica by inhalation (15 mg m(-3), 6 h per day, 5 days) and global gene expression profile was determined in the lungs by microarray analysis at 1, 2, 4, 8 and 16 weeks following termination of silica exposure. The number of significantly differentially expressed genes (>1.5-fold change and <0.01 false discovery rate P-value) detected in the lungs during the post-exposure time intervals analyzed exhibited a steady increase in parallel with the progression of silica-induced pulmonary toxicity noticed in the rats. Quantitative real-time PCR analysis of a representative set of 10 genes confirmed the microarray findings. The number of biological functions, canonical pathways and molecular networks significantly affected by silica exposure, as identified by the bioinformatics analysis of the significantly differentially expressed genes detected during the post-exposure time intervals, also exhibited a steady increase similar to the silica-induced pulmonary toxicity. Genes involved in oxidative stress, inflammation, respiratory diseases, cancer, and tissue remodeling and fibrosis were significantly differentially expressed in the rat lungs; however, unresolved inflammation was the single most significant biological response to pulmonary exposure to silica. Excessive mucus production, as implicated by significant overexpression of the pendrin coding gene, SLC26A4, was identified as a potential novel mechanism for silica-induced pulmonary toxicity. Collectively, the findings of our study provided insights into the molecular mechanisms underlying the progression of crystalline silica-induced pulmonary toxicity in the rat. Published 2012. This article is a US Government work and is in the public domain in the USA. PMID:22431001

Sellamuthu, Rajendran; Umbright, Christina; Roberts, Jenny R; Cumpston, Amy; McKinney, Walter; Chen, Bean T; Frazer, David; Li, Shengqiao; Kashon, Michael; Joseph, Pius

2013-04-01

56

Efeito da radiacao gama de cobalto 60 nas proteinas do cristalino. (Effect of (sup 60) Co gamma radiation on crystalline proteins).  

National Technical Information Service (NTIS)

In order to study the effects of (sup 6) (sup 0) Co gamma radiation on crystalline proteins an in vitro system was set up. For that, aqueous solutions from bovine crystalline were used irradiated with 0, 5.000, 10.000, 15.000, 20.000 and 25.000 Gy. The tr...

D. M. L. Bernardes

1991-01-01

57

Radiation-Induced Grafting on Polyamides.  

National Technical Information Service (NTIS)

The objective of the project was to investigate radiation-induced grafting on polyamides, with emphasis on fluorine-containg vinyl monomers. The principal experimental technique was the gamma ray irradiation of polyamide film samples immersed in suitable ...

J. E. Wilson

1972-01-01

58

Mesoscale modeling of strain induced solid state amorphization in crystalline materials  

NASA Astrophysics Data System (ADS)

Solid state amorphization, and in particular crystalline to amorphous transformation, can be observed in metallic alloys, semiconductors, intermetallics, minerals, and also molecular crystals when they undergo irradiation, hydrogen gas dissolution, thermal interdiffusion, mechanical alloying, or mechanical milling. Although the amorphization mechanisms may be different, the transformation occurs due to the high level of disorder introduced into the material. Milling induced solid state amorphization is proposed to be the result of accumulation of crystal defects, specifically dislocations, as the material is subjected to large deformations during the high energy process. Thus, understanding the deformation mechanisms of crystalline materials will be the first step in studying solid state amorphization in crystalline materials, which not only has scientific contributions, but also technical consequences. A phase field dislocation dynamics (PFDD) approach is employed in this work to simulate plastic deformation of molecular crystals. This PFDD model has the advantage of tracking all of the dislocations in a material simultaneously. The model takes into account the elastic interaction between dislocations, the lattice resistance to dislocation motion, and the elastic interaction of dislocations with an external stress field. The PFDD model is employed to describe the deformation of molecular crystals with pharmaceutical applications, namely, single crystal sucrose, acetaminophen, gamma-indomethacin, and aspirin. Stress-strain curves are produced that result in expected anisotropic material response due to the activation of different slip systems and yield stresses that agree well with those from experiments. The PFDD model is coupled to a phase transformation model to study the relation between plastic deformation and the solid state amorphization of crystals that undergo milling. This model predicts the amorphous volume fraction in excellent agreement with experimental observation. Finally, we incorporate the effect of stress free surfaces to model the behavior of dislocations close to these surfaces and in the presence of voids.

Lei, Lei

59

Terahertz radiation induced edge currents in graphene  

Microsoft Academic Search

We report on the observation of the terahertz radiation induced edge photogalvanic effect. The directed net electric current is generated in single layer graphene by the irradiation of the samples' edges with linearly or circularly polarized terahertz laser radiation at normal incidence. We show that the directed net electric current stems from the sample edges, which reduce locally the symmetry

C. Drexler; J. Karch; P. Olbrich; M. Fehrenbacher; M. M. Glazov; S. A. Tarasenko; D. Weiss; J. Eroms; R. Yakimova; S. Lara-Avila; S. Kubatkin; E. L. Ivchenko; M. Ostler; F. Fromm; T. Seyller; S. D. Ganichev

2011-01-01

60

Radiation-induced explosive initiation  

NASA Astrophysics Data System (ADS)

A model for explosive initiation under the influence of high energy radiation has been developed. The possibility for comparing explosive initiation conditions under the influence of radiation pulse and shock wave loads of microsecond duration has been shown and the initiation conditions as a function of the radiolysis constants have been determined.

Yakovlev, M.

1999-08-01

61

Radiation-induced explosive initiation  

Microsoft Academic Search

A model for explosive initiation under the influence of high energy radiation has been developed. The possibility for comparing explosive initiation conditions under the influence of radiation pulse and shock wave loads of microsecond duration has been shown and the initiation conditions as a function of the radiolysis constants have been determined.

M. Yakovlev

1999-01-01

62

Radiation-induced transgenerational instability  

Microsoft Academic Search

To date, the analysis of mutation induction has provided an irrefutable evidence for an elevated germline mutation rate in the parents directly exposed to ionizing radiation and a number of chemical mutagens. However, the results of numerous publications suggest that radiation may also have an indirect effect on genome stability, which is transmitted through the germ line of irradiated parents

Yuri E Dubrova

2003-01-01

63

Influence of excipients in comilling on mitigating milling-induced amorphization or structural disorder of crystalline pharmaceutical actives.  

PubMed

The feasibility of using excipients to suppress the amorphization or structural disorder of crystalline salbutamol sulphate (SS) during milling was investigated. SS was subjected to ball-milling in the presence of alpha-lactose monohydrate (LAC), adipic acid (AA), magnesium stearate (MgSt), or polyvinyl pyrrolidone (PVP). X-ray powder diffraction, dynamic vapor sorption (DVS), high sensitivity differential scanning calorimetry (HSDSC) were used to analyze the crystallinity of the milled mixtures. Comilling with crystalline excipients, LAC, AA, and MgSt proved effective in reducing the amorphization of SS. LAC, AA, or MgSt acting as seed crystals to induce recrystallization of amorphous SS formed by milling. During comilling, both SS and LAC turned predominantly amorphous after 45 min but transformed back to a highly crystalline state after 60 min. Amorphous content was below the detection limits of DVS (0.5%) and HSDSC (5%). Comilled and physical mixtures of SS and ALM were stored under normal and elevated humidity conditions. This was found to prevent subsequent changes in crystallinity and morphology of comilled SS:LAC as compared to significant changes in milled SS and physical mixture. These results demonstrate a promising application of comilling with crystalline excipients in mitigating milling induced amorphization of pharmaceutical actives. PMID:19902526

Balani, Prashant N; Ng, Wai Kiong; Tan, Reginald B H; Chan, Sui Yung

2010-05-01

64

Radiation-induced lung injury  

SciTech Connect

The use of radiation therapy is limited by the occurrence of the potentially fatal clinical syndromes of radiation pneumonitis and fibrosis. Radiation pneumonitis usually becomes clinically apparent from 2 to 6 months after completion of radiation therapy. It is characterized by fever, cough, dyspnea, and alveolar infiltrates on chest roentgenogram and may be difficult to differentiate from infection or recurrent malignancy. The pathogenesis is uncertain, but appears to involve both direct lung tissue toxicity and an inflammatory response. The syndrome may resolve spontaneously or may progress to respiratory failure. Corticosteroids may be effective therapy if started early in the course of the disease. The time course for the development of radiation fibrosis is later than that for radiation pneumonitis. It is usually present by 1 year following irradiation, but may not become clinically apparent until 2 years after radiation therapy. It is characterized by the insidious onset of dyspnea on exertion. It most often is mild, but can progress to chronic respiratory failure. There is no known successful treatment for this condition. 51 references.

Rosiello, R.A.; Merrill, W.W. (Yale Univ. Medical Center, New Haven, CT (USA))

1990-03-01

65

[Quantification of radiation-induced genetic risk].  

PubMed

Associated with technical advances of our civilization is a radiation- and chemically-induced increase in the germ cell mutation rate in man. This would result in an increase in the frequency of genetic diseases and would be detrimental to future generations. It is the duty of our generation to keep this risk as low as possible. The estimation of the radiation-induced genetic risk of human populations is based on the extrapolation of results from animal experiments. Radiation-induced mutations are stochastic events. The probability of the event depends on the dose; the degree of the damage does not. The different methods to estimate the radiation-induced genetic risk will be discussed. The accuracy of the predicted results will be evaluated by a comparison with the observed incidence of dominant mutations in offspring born to radiation exposed survivors of the Hiroshima and Nagasaki atomic bombings. These methods will be used to predict the genetic damage from the fallout of the reactor accident at Chernobyl. For the exposure dose we used the upper limits of the mean effective life time equivalent dose from the fallout values in the Munich region. According to the direct method for the risk estimation we will expect for each 100 to 500 spontaneous dominant mutations one radiation-induced mutation in the first generation. With the indirect method we estimate a ratio of 100 dominant spontaneous mutations to one radiation-induced dominant mutation. The possibilities and the limitations of the different methods to estimate the genetic risk will be discussed. The discrepancy between the high safety standards for radiation protection and the low level of knowledge for the toxicological evaluation of chemical mutagens will be emphasized. PMID:3589954

Ehling, U H

1987-05-01

66

On the pressure-induced loss of crystallinity in orthophosphates of zinc and calcium  

NASA Astrophysics Data System (ADS)

A recently suggested mechanism for the stress memory of various metal phosphates is investigated experimentally. Based on first-principles simulations [N. J. Mosey et al., Science 307, 1612 (2005)], it had been argued that atoms with flexible coordination, such as zinc or heavy-metal cations, act as network-forming agents, undergoing irreversible pressure-induced changes in bonding that lead to increased connectivity between phosphate anions. In the present study, orthophosphates of zinc and calcium were exposed to high pressures on surfaces and in diamond anvil cells. An additional set of first-principles simulations was accomplished on ?-orthophosphate of zinc, which suggested that this material was already cross-linked before compression but that it nevertheless underwent a reversible coordination change under pressure in agreement with the experimental results presented here. Raman spectra indicate an irreversible, pressure-induced loss of long-range crystallinity. The pressures required to induce these changes are around 7 GPa for the zinc phosphates, while they are close to 21 GPa for the calcium phosphates. Hydrogenation of the metal phosphate lowers the threshold pressure by approximately 2-3 GPa in both cases. Moreover, ?-orthophosphate of zinc could be partially amorphisized under nonisotropic pressure on copper foils.

Shakhvorostov, Dmitry; Müser, Martin H.; Mosey, Nicholas J.; Munoz-Paniagua, David J.; Pereira, Gavin; Song, Yang; Kasrai, Masoud; Norton, Peter R.

2008-02-01

67

Crystalline Membranes  

NASA Technical Reports Server (NTRS)

In certain aspects, the invention features methods for forming crystalline membranes (e.g., a membrane of a framework material, such as a zeolite) by inducing secondary growth in a layer of oriented seed crystals. The rate of growth of the seed crystals in the plane of the substrate is controlled to be comparable to the rate of growth out of the plane. As a result, a crystalline membrane can form a substantially continuous layer including grains of uniform crystallographic orientation that extend through the depth of the layer.

Tsapatsis, Michael (Inventor); Lai, Zhiping (Inventor)

2008-01-01

68

Polyaniline fibers, films, and powders: X-ray studies of crystallinity and stress-induced preferred orientation  

SciTech Connect

Powder (hk0) and four-circle X-ray diffractometry are used to study the effects of hot-stretching on films and fibers of the emeralidine base form of polyaniline (EB-II). It is shown definitively that hot-stretching induces nucleation of new crystalline material rather than growth and/or orientation of pre-existing crystallites. The diffuse scattering from amorphous EB-II is dominated by short-range interchain correlations and develops preferred orientation in response to stretching but with a broader mosaic than the crystalline phase. For the maximally-stretched samples, the crystal fractions was determined by accounting for the different mosaic distributions of crystalline and amorphous phases, correcting for the mass of N-methylphenazolinium plasticizer and ruling out any significant contribution from NMP diffuse scattering to the amorphous EB-II profiles. Films stretched to L/L[sub 0] = 4.25 contain no more than 4% crystalline material while fibers with L/L[sub 0] = 4.5 are 24--30% crystalline. These fractional crystallinity values are significantly small than found for EB-II powder (60%). More importantly, these results have implications for models of electric properties which invoke interchain interactions.

Fischer, J.E.; Zhu, Q.; Tang, X.; Scherr, E.M.; MacDiarmid, A.G. (Univ. of Pennsylvania, Philadelphia, PA (United States). Lab. for Research on the Structure of Matter); Cajipe, V.B. (CNRS-UMR 110, Nantes (France). Inst. des Materiaux des Nantes)

1994-08-29

69

Radiation-induced squamous sialometaplasia  

SciTech Connect

We describe a patient with recurrent acantholytic squamous cell carcinoma following radiation therapy. Mohs micrographic sections revealed extensive squamous sialometaplasia showing striking histologic similarity to the patient's squamous cell carcinoma. Criteria necessary to differentiate squamous sialometaplasia from neoplasm are presented. This differentiation is important to ensure adequate tumor resection without unnecessary sacrifice of tumor-free tissue.

Leshin, B.; White, W.L.; Koufman, J.A. (Wake Forest Univ., Winston-Salem, NC (USA))

1990-07-01

70

PH-Induced Nanosegregation of Ritonavir to Lyotropic Liquid Crystal of Higher Solubility Than Crystalline Polymorphs  

SciTech Connect

Birefringent spherical vesicles of ritonavir (RTV) are formed by increasing the pH of aqueous solutions from 1 to 3 or to 7 and by addition of water to ethanol solutions at room temperature. Increasing the pH creates supersaturation levels of 30--400. Upon this change in pH, the solutions become translucent, implying that some kind of RTV assembly was formed. Small spherical vesicles of narrow size distribution are detectable only after a few hours by optical microscopy. The vesicles show similar X-ray diffraction patterns and differential scanning calorimetry (DSC) behavior to amorphous RTV prepared by melt-quenching crystalline RTV. Examination by polarized optical microscopy suggests that these are lyotropic liquid crystalline (LLC) assemblies. Small-angle X-ray scattering and synchrotron X-ray diffraction further support the presence of orientational order that is associated with a nematic structure. RTV self-organizes into various phases as a result of the supersaturation created in aqueous solutions. The LLC vesicles do not fuse but slowly transform to the polymorphs of RTV (in days), Form I and finally Form II. Amorphous RTV in aqueous suspension also undergoes a transformation to a mesophase of similar morphology. Transformation pathways are consistent with measured dissolution rates and solubilities: amorphous > LLC >> Form I > Form II. The dissolution and solubility of LLC is slightly lower than that of the amorphous phase and about 20 times higher than that of Form II. RTV also self-assembles at the air/water interface as indicated by the decrease in surface tension of aqueous solutions. This behavior is similar to that of amphiphilic molecules that induce LLC formation.

Rodriguez-Spong, B.; Acciacca, A.; Fleisher, D.; Rodriguez-Hornedo, N.

2009-05-27

71

PH-induced nanosegregation of ritonavir to lyotropic liquid crystal of higher solubility than crystalline polymorphs.  

PubMed

Birefringent spherical vesicles of ritonavir (RTV) are formed by increasing the pH of aqueous solutions from 1 to 3 or to 7 and by addition of water to ethanol solutions at room temperature. Increasing the pH creates supersaturation levels of 30-400. Upon this change in pH, the solutions become translucent, implying that some kind of RTV assembly was formed. Small spherical vesicles of narrow size distribution are detectable only after a few hours by optical microscopy. The vesicles show similar X-ray diffraction patterns and differential scanning calorimetry (DSC) behavior to amorphous RTV prepared by melt-quenching crystalline RTV. Examination by polarized optical microscopy suggests that these are lyotropic liquid crystalline (LLC) assemblies. Small-angle X-ray scattering and synchrotron X-ray diffraction further support the presence of orientational order that is associated with a nematic structure. RTV self-organizes into various phases as a result of the supersaturation created in aqueous solutions. The LLC vesicles do not fuse but slowly transform to the polymorphs of RTV (in days), Form I and finally Form II. Amorphous RTV in aqueous suspension also undergoes a transformation to a mesophase of similar morphology. Transformation pathways are consistent with measured dissolution rates and solubilities: amorphous > LLC > Form I > Form II. The dissolution and solubility of LLC is slightly lower than that of the amorphous phase and about 20 times higher than that of Form II. RTV also self-assembles at the air/water interface as indicated by the decrease in surface tension of aqueous solutions. This behavior is similar to that of amphiphilic molecules that induce LLC formation. PMID:19434919

Rodríguez-Spong, Barbara; Acciacca, Alison; Fleisher, David; Rodríguez-Hornedo, Naír

2008-01-01

72

Lateral solidification of a liquid crystalline semiconductor film induced by temperature gradient  

NASA Astrophysics Data System (ADS)

Derivatives of [1]benzothieno[3,2-b]benzothiophene (BTBT) are attracting much attention as a highly soluble, highmobility semiconductor material for thin-film transistor applications. These small molecules are known to organize themselves into a single crystalline structure after spin coating or drop casting. Charge transport in a single crystal material is anisotropic in nature. Hence, it is desired to control its orientation during growth or recrystallization so that the source and drain electrodes of a transistor are to be placed along a faster transport direction. We propose to generate temperature gradient in a heated liquid crystalline thin film to induce lateral recrystallization. In experiment, we tried two methods. First, an aluminum plate with two narrow ridges was inserted between a temperature-controlled stage and a square silicon substrate with a 200nm-thick SiO2 and a spin-coated C8-BTBT film. We raised the temperature of the stage to 120oC and let it cool gradually. During cooling at around 105oC , the color of the sample started to change, indicating a phase change. This change proceeded from the corners of the film and in about 30 seconds, darker regions merged at the center of the substrate. Second, the sample was placed at the edge of the stage. In this case, the color change started from the protruding corner of the sample and proceeded toward the other end. Micrograph observation revealed that cracks were formed in these films and they were perpendicular to the direction of the phase change.

Hoshino, Tomoya; Ito, Hayato; Fujieda, Ichiro; Hanasaki, Tomonori

2013-09-01

73

Radiation Induces Acute Alterations in Neuronal Function  

PubMed Central

Every year, nearly 200,000 patients undergo radiation for brain tumors. For both patients and caregivers the most distressing adverse effect is impaired cognition. Efforts to protect against this debilitating effect have suffered from inadequate understanding of the cellular mechanisms of radiation damage. In the past it was accepted that radiation-induced normal tissue injury resulted from a progressive reduction in the survival of clonogenic cells. Moreover, because radiation-induced brain dysfunction is believed to evolve over months to years, most studies have focused on late changes in brain parenchyma. However, clinically, acute changes in cognition are also observed. Because neurons are fully differentiated post-mitotic cells, little information exists on the acute effects of radiation on synaptic function. The purpose of our study was to assess the potential acute effects of radiation on neuronal function utilizing ex vivo hippocampal brain slices. The cellular localization and functional status of excitatory and inhibitory neurotransmitter receptors was identified by immunoblotting. Electrophysiological recordings were obtained both for populations of neuronal cells and individual neurons. In the dentate gyrus region of isolated ex vivo slices, radiation led to early decreases in tyrosine phosphorylation and removal of excitatory N-methyl-D-aspartate receptors (NMDARs) from the cell surface while simultaneously increasing the surface expression of inhibitory gamma-aminobutyric acid receptors (GABAARs). These alterations in cellular localization corresponded with altered synaptic responses and inhibition of long-term potentiation. The non-competitive NMDAR antagonist memantine blocked these radiation-induced alterations in cellular distribution. These findings demonstrate acute effects of radiation on neuronal cells within isolated brain slices and open new avenues for study.

Wu, Peter H.; Coultrap, Steven; Pinnix, Chelsea; Davies, Kurtis D.; Tailor, Ramesh; Ang, Kian K.; Browning, Michael D.; Grosshans, David R.

2012-01-01

74

Imaging Radiation-Induced Normal Tissue Injury  

PubMed Central

Technological developments in radiation therapy and other cancer therapies have led to a progressive increase in five-year survival rates over the last few decades. Although acute effects have been largely minimized by both technical advances and medical interventions, late effects remain a concern. Indeed, the need to identify those individuals who will develop radiation-induced late effects, and to develop interventions to prevent or ameliorate these late effects is a critical area of radiobiology research. In the last two decades, preclinical studies have clearly established that late radiation injury can be prevented/ameliorated by pharmacological therapies aimed at modulating the cascade of events leading to the clinical expression of radiation-induced late effects. These insights have been accompanied by significant technological advances in imaging that are moving radiation oncology and normal tissue radiobiology from disciplines driven by anatomy and macrostructure to ones in which important quantitative functional, microstructural, and metabolic data can be noninvasively and serially determined. In the current article, we review use of positron emission tomography (PET), single photon emission tomography (SPECT), magnetic resonance (MR) imaging and MR spectroscopy to generate pathophysiological and functional data in the central nervous system, lung, and heart that offer the promise of, (1) identifying individuals who are at risk of developing radiation-induced late effects, and (2) monitoring the efficacy of interventions to prevent/ameliorate them.

Robbins, Mike E.; Brunso-Bechtold, Judy K.; Peiffer, Ann M.; Tsien, Christina I.; Bailey, Janet E.; Marks, Lawrence B.

2013-01-01

75

Radiation induced conductivity in space dielectric materials  

NASA Astrophysics Data System (ADS)

The radiation-induced conductivity of some polymers was described mainly in literature by a competition between ionization, trapping/detrapping, and recombination processes or by radiation assisted ageing mechanisms. Our aim is to revise the effect of the aforementioned mechanisms on the complex evolution of Teflon® FEP under space representative ionizing radiation. Through the definition of a new experimental protocol, revealing the effect of radiation dose and relaxation time, we have been able to demonstrate that the trapping/recombination model devised in this study agrees correctly with the observed experimental phenomenology at qualitative level and allows describing very well the evolution of radiation induced conductivity with irradiation time (or received radiation dose). According to this model, the complex behavior observed on Teflon® FEP may be basically ascribed to the competition between electron/hole pairs generation and recombination: electrons are deeply trapped and act as recombination centers for free holes. Relaxation effects have been characterized through successive irradiations steps and have been again well described with the defined model at qualitative level: recombination centers created by the irradiation induce long term alteration on the electric properties, especially the effective bulk conductivity. One-month relaxation does not allow a complete recovery of the material initial charging behavior.

Hanna, R.; Paulmier, T.; Molinie, P.; Belhaj, M.; Dirassen, B.; Payan, D.; Balcon, N.

2014-01-01

76

Radiation-induced long thoracic nerve palsy  

SciTech Connect

The incidence of long thoracic nerve palsy after radical mastectomy has been documented to be approximately 10%. No cases have been reported after the more recent treatment for breast cancer, lumpectomy with axillary dissection. This more recent surgical procedure is customarily followed by aggressive radiation therapy to the remaining breast tissue. This is the first case report of a patient with radiation-induced long thoracic nerve palsy. The patient was a young woman who underwent left breast quadrantectomy and axillary dissection for breast cancer. After radiation therapy, she had isolated left long thoracic nerve palsy. The diagnosis was confirmed by electrodiagnostic studies. Almost full recovery occurred after 5 months.

Pugliese, G.N.; Green, R.F.; Antonacci, A.

1987-09-15

77

Racemization of lens crystalline constituents in UV-induced cataract evaluated by chiral GC/MS spectroscopy.  

PubMed

The racemization of amino acids is hypothesized to cause cataract by disrupting the crystalline's tertiary structure, which, in turn, alters the optical characteristics of the lens. To better understand the role of these modifications in cataractogenesis, the changes in stereoisomer ratio of amino acids from lens crystalline by UV-B-induced cataract in animal models were studied using chiral separation gas chromatography-single quadrupole mass spectroscopy. The anticataract action of a compound, ([1-(phenylmethyl)-1H-indazol-3-yl]oxy)acetic acid lysinate, was also evaluated by this method. PMID:8883086

Jung, W T; Rho, S H; Park, W C

1996-01-01

78

Radiation-Induced Phase Transformations in Ilmenite-Group Minerals  

SciTech Connect

Transmission electron microscopy (TEM) is a powerful tool for characterizing and understanding radiation-induced structural changes in materials. We have irradiated single crystals of ilmenite (FeTiO{sub 3}) and geikielite (MgTiO{sub 3}) using ions and electrons to better understand the response of complex oxides to radiation. Ion irradiation experiments of bulk single crystals at 100 K show that ilmenite amorphized at doses of less than 1x10(exp15) Ar(2+)/sq cm and at a damage level in the peak damage region of 1 displacement per atom (dpa). Transmission electron microscopy and electron diffraction of a cross-sectioned portion of this crystal confirmed the formation of a 150 am thick amorphous layer. Geikielite proved to be more radiation resistant, requiring a flux of 2x10(exp 15) Xe(2+)/sq cm to induce amorphization at 100 K. This material did not amorphize at 470 K, despite a dose of 2.5 x10(exp 16) Xe(2+)/sq cm and a damage level as high as 25 dpa. Low temperature irradiations of electron- transparent crystals with 1 MeV Kr(+) also show that ilmenite amorphized after a damage level of 2.25 dpa at 175 K.Similar experiments on geikielite show that the microstructure is partially amorphous and partially crystalline after 10 dpa at 150 K. Concurrent ion and electron irradiation of both materials with 1 MeV Kr(+) and 0.9 MeV electrons produced dislocation loops in both materials, but no amorphous regions were formed. Differences in the radiation response of these isostructural oxides suggests that in systems with Mg-Fe solid solution, the Mg-rich compositions may be more resistant to structural changes.

Mitchell, J. N.

1997-12-31

79

Radiation-induced Genomic Instability and Radiation Sensitivity  

SciTech Connect

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.

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

2013-01-19

80

Ultrafast sub-threshold photo-induced response in crystalline and amorphous GeSbTe thin films  

NASA Astrophysics Data System (ADS)

Pump-probe optical reflectivity and terahertz transmission measurements have been used to investigate time resolved sub-threshold photo-induced effects in crystalline and amorphous GeSbTe films at MHz repetition rates. The reflectivity in both phases exhibits long-lived modulations consistent with the sign of the changes that occur upon switching but of smaller magnitude. These can be understood by the generation of acoustic strains with the crystalline phase response dominated by thermal effects and the amorphous phase response associated with electronically induced changes. Evidence for a photo-induced distortion is observed in the amorphous phase which develops homogeneously within the excited region on few-picosecond time scales.

Shu, M. J.; Chatzakis, I.; Kuo, Y.; Zalden, P.; Lindenberg, A. M.

2013-05-01

81

Radiation-Induced Grafting on Polyamides.  

National Technical Information Service (NTIS)

Earlier work indicated that in the radiation-induced grafting of vinyl monomers on polymeric films, the plasticity of the film being grafted is determined by the Hildebrand solubility parameter of the grafting solution. In the grafting of styrene on nylon...

J. E. Wilson

1973-01-01

82

Monitor for Radiation-Induced Heating.  

National Technical Information Service (NTIS)

The patent relates to a susceptive material that is to be examined with respect to radiation-induced heating sealed within a capsule composed of a material such as stainless steel. The remaining capsule volume is filled with a liquid metal that has a grea...

W. R. Wallin V. W. Lowery R. R. Smith

1974-01-01

83

Immunity induced by a broad class of inorganic crystalline materials is directly controlled by their chemistry.  

PubMed

There is currently no paradigm in immunology that enables an accurate prediction of how the immune system will respond to any given agent. Here we show that the immunological responses induced by members of a broad class of inorganic crystalline materials are controlled purely by their physicochemical properties in a highly predictable manner. We show that structurally and chemically homogeneous layered double hydroxides (LDHs) can elicit diverse human dendritic cell responses in vitro. Using a systems vaccinology approach, we find that every measured response can be modeled using a subset of just three physical and chemical properties for all compounds tested. This correlation can be reduced to a simple linear equation that enables the immunological responses stimulated by newly synthesized LDHs to be predicted in advance from these three parameters alone. We also show that mouse antigen-specific antibody responses in vivo and human macrophage responses in vitro are controlled by the same properties, suggesting they may control diverse responses at both individual component and global levels of immunity. This study demonstrates that immunity can be determined purely by chemistry and opens the possibility of rational manipulation of immunity for therapeutic purposes. PMID:24799501

Williams, Gareth R; Fierens, Kaat; Preston, Stephen G; Lunn, Daniel; Rysnik, Oliwia; De Prijck, Sofie; Kool, Mirjam; Buckley, Hannah C; Lambrecht, Bart N; O'Hare, Dermot; Austyn, Jonathan M

2014-06-01

84

Hydrogen-bond induced side-chain liquid crystalline polymers based on nicotinic acid derivatives  

Microsoft Academic Search

Supramolecular side-chain liquid crystalline poly(acrylate)s have been prepared by self-assembly of H-bond donor and acceptor complexes through intermolecular complementary hydrogen bond formation. Poly[4-(m-acryloyloxyalkyloxy)benzoic acid]s [m=6 (P1) and 8 (P2)] were employed as polymer components. Liquid crystalline nicotinic acid derivatives (C1, C2, C3, and C4) were used as complementary H-bond donor\\/acceptor counterparts. The liquid crystalline properties of the nicotinic acid derivatives,

C. Saravanan; V. Ambili; P. Kannan

2010-01-01

85

Delayed Radiation-Induced Vasculitic Leukoencephalopathy  

SciTech Connect

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.

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

86

Genistein mitigates radiation-induced testicular injury.  

PubMed

The present study investigated the radioprotective effect of a multifunctional soy isoflavone, genistein, with the testicular system. Genistein was administered (200?mg/kg body weight) to male C3H/HeN mice by subcutaneous injection 24?h prior to pelvic irradiation (5?Gy). Histopathological parameters were evaluated 12?h and 21?days post-irradiation. Genistein protected the germ cells from radiation-induced apoptosis (p?radiation-induced reduction in testis weight, seminiferous tubular diameter, seminiferous epithelial depth and sperm head count in the testes (p?radiation-induced ROS production. The results indicate that genistein protects from testicular dysfunction induced by gamma-irradiation by an antiapoptotic effect and recovery of spermatogenesis. PMID:22162311

Kim, Joong-Sun; Heo, Kyu; Yi, Joo-Mi; Gong, Eun Ji; Yang, Kwangmo; Moon, Changjong; Kim, Sung-Ho

2012-08-01

87

Laser-induced damage of single-crystalline silicon under different 1064-nm Nd:YAG laser modes  

NASA Astrophysics Data System (ADS)

The Laser-induced damage behavior of single-Crystalline Silicon was investigated with a Nd:YAG laser at 1064nm under single-pulse mode and free-running mode. It was found that the damage behavior of the SCS showed strong dependence on the output mode of the incident laser. From the experimental and theoretical analysis, the damage mechanism under the two laser modes were given based on thermal and thermal-stress coupling models.

Gao, WeiDong; Zhan, Meiqiong; Shao, Janda; Fan, Zhengxiu

2005-01-01

88

Rdiasensitivity and radiation-induced mutability: an empirical relationship.  

PubMed

The total genome size of various species can apparently define the radiation-induced mutability and radiosensitivity for these species. An empirical expression has been derived which relates the radiation-induced mutation rates of different species to their total DNA content and radiation-induced inactivation rates. PMID:1202558

Trujillo, R; Dugan, V L

1975-10-01

89

Amorphous silicon/crystalline silicon heterojunctions for nuclear radiation detector applications  

SciTech Connect

Results on characterization of electrical properties of amorphous Si films for the 3 different growth methods (RF sputtering, PECVD [plasma enhanced], LPCVD [low pressure]) are reported. Performance of these a-Si films as heterojunctions on high resistivity p-type and n- type crystalline Si is examined by measuring the noise, leakage current, and the alpha particle response of 5mm dia detector structures. It is demonstrated that heterojunction detectors formed by RF sputtered films and PECVD films are comparable in performance with conventional surface barrier detectors. Results indicate that the a-Si/c-Si heterojunctions have the potential to greatly simplify detector fabrication. Directions for future avenues of nuclear particle detector development are indicated.

Walton, J.T.; Hong, W.S.; Luke, P.N.; Wang, N.W. [Lawrence Berkeley National Lab., CA (United States); Ziemba, F.P. [Quantrad Sensor, Inc., Santa Clara, CA (United States)

1996-10-01

90

PROTON TUNNELING IN RADIATION-INDUCED MUTATION.  

PubMed

The equilibrium proton distribution and tunneling rate in the N-H. . . N hydrogen bond of the guanine-cytosine base pair have been calculated quantum mechanically for the ground state, a charge-transfer excited state, and positive and negative ionic states. These results are consistent with the idea that tautomeric rearrangement can be a cause of radiation induced mutation or carcinogenesis. PMID:14191703

REIN, R; HARRIS, F E

1964-10-30

91

Radiation-induced dechlorination of hexachlorobenzene  

NASA Astrophysics Data System (ADS)

A study on radiation-induced dechlorination of hexachlorobenzene in alkaline ethanol solution was performed. At the beginning a higher efficiency for dechlorination has been found. The dechlorination is a chain reaction. The solubility of radiolytic products in ethanol-water (v/v 1:4) is higher than that of HCB in the same solvent. Hexachlorobenzene could be transfered into the solution and degraded partially if the soil contaminated by hexachlorobenzene was mixed with ethanol, then irradiated with ?-rays.

Yongke, He; Hongtao, Chen; Xiangrong, Sheng; Jilan, Wu

1993-10-01

92

Role of neurotensin in radiation-induced hypothermia in rats  

SciTech Connect

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.

Kandasamy, S.B.; Hunt, W.A.; Harris, A.H. (Armed Forces Radiobiology Research Institute, Bethesda, MD (USA))

1991-05-01

93

Characteristics of metal-induced crystallization/dopant activation and its application to junction diodes on single-crystalline silicon  

NASA Astrophysics Data System (ADS)

In this work, we investigated the effect of p- and n-type dopant atoms (boron and phosphorus) on two- and one-step Ni metal-induced crystallization (MIC) of amorphous Si in the aspects of crystallization rate and crystal quality with XRD, SIMS and sheet resistance measurements. The two- and one-step MIC techniques were first applied to fabricate p+/n and n+/p junction diodes on single-crystalline Si substrates below 500 °C and we compared those with the diodes formed by the solid phase crystallization technique at 750 °C, in order to demonstrate the feasibility of the low-temperature MIC junction diodes for source/drain of p- and n-channel single-crystalline Si TFTs.

Jung, Woo-Shik; Park, Jin-Hong; Jung, Hyun-Wook; Saraswat, Krishna C.

2012-06-01

94

Effect on thickness of Al layer in poly-crystalline Si thin films using aluminum(Al) induced crystallization method.  

PubMed

The polycrystalline silicon (poly-Si) thin films were prepared by aluminum induced crystallization. Aluminum (Al) and amorphous silicon (a-Si) layers were deposited using DC sputtering and plasma enhanced chemical vapor deposition method, respectively. For the whole process Al properties of bi-layers can be one of the important factors. In this paper we investigated the structural and electrical properties of poly-crystalline Si thin films with a variation of Al thickness through simple annealing process. All samples showed the polycrystalline phase corresponding to (111), (311) and (400) orientation. Process time, defined as the time required to reach 95% of crystalline fraction, was within 60 min and Al(200 nm)/a-Si(400 nm) structure of bi-layer showed the fast response for the poly-Si films. The conditions with a variation of Al thickness were executed in preparing the continuous poly-Si films for solar cell application. PMID:21456186

Jeong, Chaehwan; Na, Hyeon Sik; Lee, Suk Ho

2011-02-01

95

Radiation induced genomic instability in bystander cells  

NASA Astrophysics Data System (ADS)

There is considerable evidence that exposure to ionizing radiation may induce a heritable genomic instability that leads to a persisting increased frequency of genetic and functional changes in the non-irradiated progeny of a wide variety of irradiated cells Genomic instability is measured as delayed expressions in chromosomal alterations micronucleus formation gene mutations and decreased plating efficiency During the last decade numerous studies have shown that radiation could induce bystander effect in non-irradiated neighboring cells similar endpoints have also been used in genomic instability studies Both genomic instability and the bystander effect are phenomena that result in a paradigm shift in our understanding of radiation biology In the past it seemed reasonable to assume that the production of single- and double-strand DNA breaks are due to direct energy deposition of energy by a charged particle to the nucleus It turns out that biology is not quite that simple Using the Columbia University charged particle microbeam and the highly sensitive human hamster hybrid AL cell mutagenic assay we irradiated 10 of the cells with a lethal dose of 30 alpha particles through the nucleus After overnight incubation the remaining viable bystander cells were replated in dishes for colony formation Clonal isolates were expanded and cultured for 6 consecutive weeks to assess plating efficiency and mutation frequency Preliminary results indicated that there was no significant decrease in plating efficiency among the bystander colonies when compared with

Zhou, H.; Gu, S.; Randers-Pehrson, G.; Hei, T.

96

Cathodoluminescence of radiation-induced zircon  

NASA Astrophysics Data System (ADS)

Zircon occurs as a common accessory mineral in igneous, metamorphic and sedimentary rocks, and maintains much information on thermal history, metamorphic process and natural radiation dose accumulated in the mineral. U-Pb zircon dating (e.g., SHRIMP) is an important tool to interpret a history of the minerals at a micrometer-scale, where cathodoluminescence (CL) image has been used for identification of internal zones and domains having different chemical compositions and/or structures with a high spatial resolution. The CL of zircon is derived from various types of emission centers, which are derived from impurities such as rare earth elements (REE) and structural defects. In fact, the CL features of zircon are closely related to metamorphic process and radiation from contained radionuclides as well as geochemical condition of its formation. Most zircon has yellow emission, which seems to be assigned to UO2 centers or radiation-induced defect during metamictization of the lattice by alpha particles from the decay of U and Th. In this study, the radiation effects on zircon CL have been studied for He+ ion-implanted samples annealed at various temperatures to clarify radiation-induced defect centers involved with the yellow CL emission in zircon. Single crystals of zircon from Malawi (MZ), Takidani granodiorite (TZ) and Kurobegawa granite (KZ) were selected for He+ ion implantation experiments. The polished plates of the samples were implanted by He+ ion 4.0 MeV corresponding to energy of alpha particle from 238 U and 232Th. CL spectra in the range from 300 to 800 nm with 1 nm step were measured by a scanning electron microscopy-cathodoluminescence (SEM-CL). CL spectra of untreated and annealed zircon show emission bands at ~370 nm assigned to intrinsic defect centers and at ~480, ~580 and ~760 nm to trivalent Dy impurity centers (Cesbron et al., 1995; Gaft et al, 2005). CL emissions in the yellow-region were observed in untreated zircon. The TZ and KZ indicate youngest formation ages of 1.93-1.20 Ma and 1.7-0.9 Ma, respectively (Harayama,1994; Harayama et al., 2010) in the world. In this case, it is hardly to detect yellow CL emissions derived from radiation-induced defect center, suggesting low radiation dose of alpha radiation from 238U and 232Th on them. CL spectra of MZ, TZ and KZ showed an increase in the intensities of yellow emissions with an increase in radiation dose of He+ ion implantation, though He+ ion implantation reduces the intensities of their impurity centers. CL intensity in the yellow region depends on radiation dose of He+ ion implantation. Therefore, if the component of yellow emission could be deconvoluted from the CL spectra in zircon, its intensity will be used for an indicator to evaluate total exposure doses on it during geological age.

Tsuchiya, Y.; Nishido, H.; Kayama, M.; Noumi, Y.

2013-12-01

97

Management of radiation-induced rectal bleeding.  

PubMed

Pelvic radiation disease is one of the major complication after radiotherapy for pelvic cancers. The most commonly reported symptom is rectal bleeding which affects patients' quality of life. Therapeutic strategies for rectal bleeding are generally ignored and include medical, endoscopic, and hyperbaric oxygen treatments. Most cases of radiation-induced bleeding are mild and self-limiting, and treatment is normally not indicated. In cases of clinically significant bleeding (i.e. anaemia), medical therapies, including stool softeners, sucralfate enemas, and metronidazole, should be considered as first-line treatment options. In cases of failure, endoscopic therapy, mainly represented by argon plasma coagulation and hyperbaric oxygen treatments, are valid and complementary second-line treatment strategies. Although current treatment options are not always supported by high-quality studies, patients should be reassured that treatment options exist and success is achieved in most cases if the patient is referred to a dedicated centre. PMID:24101202

Laterza, Liboria; Cecinato, Paolo; Guido, Alessandra; Mussetto, Alessandro; Fuccio, Lorenzo

2013-11-01

98

Radiation-induced electron migration along DNA  

SciTech Connect

Radiation-induced electron migration along DNA is a mechanism by which randomly produced stochastic energy deposition events can lead to nonrandom types of damage along DNA manifested distal to the sites of the initial energy deposition. Electron migration along DNA is significantly influenced by the DNA base sequence and DNA conformation. Migration along 7 base pairs in oligonucleotides containing guanine bases was observed for oligonucleotides irradiated in solution which compares to average migration distances of 6 to 10 bases for Escherichia coli DNA irradiated in solution and 5.5 base pairs for Escherichia coli DNA irradiated in cells. Evidence also suggests that electron migration can occur preferentially in the 5{prime} to 3{prime} direction along DNA. Our continued efforts will provide information regarding the contribution of electron transfer along DNA to formation of locally multiply damaged sites created in DNA by exposure to ionizing radiation.

Fuciarelli, A.F.; Sisk, E.C.; Miller, J.H. [Pacific Northwest Lab., Richland, WA (United States); Zimbrick, J.D. [National Research Council, Washington, DC (United States)

1994-04-01

99

Radiation-induced chronic arterial injury  

SciTech Connect

Acute arterial disruption associated with infection, previous irradiation, and the postoperative state is a well-described entity. The recognition of a chronic form of radiation-induced arterial injury presenting years after therapeutic doses of radiation is less well appreciated. This paper summarizes the vital data obtained by reviewing the literature concerning 162 cases of arterial injury associated with prior radiotherapy. The vessels involved include coronary arteries, the aorta, renal arteries, the extra- and intracranial circulation, the ilio-femoral system, and the upper extremity arteries. A review of the histologic findings, the studies regarding pathogenesis, and the morphology of the lesions found in these 162 patients suggests a disease distinct from the atherosclerotic process. 181 references.

Himmel, P.D.; Hassett, J.M.

1986-01-01

100

Radiation-induced osteosarcoma of the sphenoid bone  

SciTech Connect

The case of a patient who developed osteosarcoma in the sphenoid bone 15 years after radiation therapy for a craniopharyngioma is reported. Radiation-induced osteosarcoma of the sphenoid bone has not been reported previously. Reported cases of radiation-induced osteosarcomas are reviewed.

Tanaka, S.; Nishio, S.; Morioka, T.; Fukui, M.; Kitamura, K.; Hikita, K. (Kyushui Univ., Fukuoka (Japan))

1989-10-01

101

Synchronous radiation-induced orbital meningioma and multiple cavernomas.  

PubMed

Synchronous radiation-induced tumours are extremely rare. We present the first reported case of synchronous radiation-induced orbital meningioma and cavernomas of the cerebellum and bilateral basal ganglia, presenting 16 years after ionizing radiation therapy for parietal anaplastic ependymoma, at the age of five. This case again underscores the risks of radiotherapy to children. PMID:20491803

Paramanathan, Nirosha; Ooi, Kenneth Gek-Jin; Reeves, Dianne; Wilcsek, Geoff A

2010-05-01

102

Spatial distribution of radiation damage to crystalline proteins at 25-300 K  

PubMed Central

The spatial distribution of radiation damage (assayed by increases in atomic B factors) to thaumatin and urease crystals at temperatures ranging from 25 to 300?K is reported. The nature of the damage changes dramatically at approximately 180?K. Above this temperature the role of solvent diffusion is apparent in thaumatin crystals, as solvent-exposed turns and loops are especially sensitive. In urease, a flap covering the active site is the most sensitive part of the molecule and nearby loops show enhanced sensitivity. Below 180?K sensitivity is correlated with poor local packing, especially in thaumatin. At all temperatures, the component of the damage that is spatially uniform within the unit cell accounts for more than half of the total increase in the atomic B factors and correlates with changes in mosaicity. This component may arise from lattice-level, rather than local, disorder. The effects of primary structure on radiation sensitivity are small compared with those of tertiary structure, local packing, solvent accessibility and crystal contacts.

Warkentin, Matthew; Badeau, Ryan; Hopkins, Jesse B.; Thorne, Robert E.

2012-01-01

103

Radiation Induced Bystander Effects in Human Lymphoblastoid Cells.  

National Technical Information Service (NTIS)

It is well accepted that cells, in response to radiation, may release transmissible factors. These transmissible factors, clastogenic factors, have been reported to induce genomic instability in cells that have not been directly exposed to radiation. We h...

T. M. Segura D. Wilkinson L. Prud'honne-Lalonde E. M. Thorleifson S. Lachapelle

2003-01-01

104

YAG laser-induced crystalline dot patterning in samarium tellurite glasses  

Microsoft Academic Search

A CW YAG laser with a wavelength of 1064 nm and with a power of 1 W has been used to irradiate samarium tellurite glasses with the compositions of 10RO·10Sm2O3·80TeO2 (R=Mg, Ba) at room temperature for 30–60 s. It is found from polarized optical microscopy and from X-ray diffraction (XRD) analyses that crystalline dot patterns with sharp refractive index changes

Ryuji Sato; Yasuhiko Benino; Takumi Fujiwara; Takayuki Komatsu

2001-01-01

105

Radiation-induced intracranial meningioma and multiple cavernomas.  

PubMed

Brain irradiation has several well-known long-term side effects, including radiation-induced neoplasms and vasculopathy. In this case report, we describe an extremely rare case of meningioma and 15 cavernomas developing in a 29-year-old man, 19 years after cranial irradiation for posterior cranial fossa medulloblastoma. To our knowledge, this is the first case of a radiation-induced meningioma accompanied by this many radiation-induced cavernous angiomas. PMID:24051144

Chourmouzi, Danai; Papadopoulou, Elissavet; Kontopoulos, Athanasios; Drevelegas, Antonios

2013-01-01

106

Semi-interpenetrating polymer networks of poly(3-hydroxybutyrate) prepared by radiation-induced polymerization  

NASA Astrophysics Data System (ADS)

Semi-interpenetrating polymer networks (IPNs) based on bacterial poly(3-hydroxy butyrate) with a hydrophilic monomer at different compositions were prepared by radiation-induced polymerization using ?-rays from a 60Co source with a total dose of 10-100 kGy. The swelling behaviour was determined by water content at equilibrium, while thermal properties and crystallinity were studied by differential scanning calorimetry. Extraction of the soluble part of PHB from the films at low and high temperature with water or chloroform as well as FTIR data indicate the occurrence of the crosslinking reaction in the hydrogels. The results show a water uptake increasing with the hydrophilic component until 25%.

Martellini, Flavia; Innocentini Mei, Lúcia H.; Lora, Silvano; Carenza, Mario

2004-09-01

107

On the theory of the shear-induced isotropic-to-nematic phase transition of side chain liquid-crystalline polymers  

Microsoft Academic Search

The shear-induced isotropic-to-nematic phase transition of side chain liquid-crystalline polymers is studied theoretically. A modification of the previous models of main-chain liquid crystals to the case of side chain liquid-crystalline polymers is proposed. Orientational and rheological properties of the model are studied in plane-shear flow. Predictions of the present model agree qualitatively with experimental results (Pujolle-Robic, Noirez in Nature 409:167,

Siegfried Hess; Patrick Ilg

2005-01-01

108

Laser-Induced Forward Transfer-printing of focused ion beam pre-machined crystalline magneto-optic yttrium iron garnet micro-discs.  

PubMed

We present femtosecond laser-induced forward transfer of focused ion beam pre-machined discs of crystalline magneto-optic yttrium iron garnet (YIG) films. Debris-free circular micro-discs with smooth edges and surface uniformity have been successfully printed. The crystalline nature of the printed micro-discs has not been altered by the LIFT printing process, as was confirmed via micro-Raman measurements. PMID:22772215

Sones, C L; Feinaeugle, M; Sposito, A; Gholipour, B; Eason, R W

2012-07-01

109

Ion beam induced luminescence: Relevance to radiation induced bystander effects  

NASA Astrophysics Data System (ADS)

The aim of this work is quantify the light emitted as a result of charged particle interaction in materials which may be of relevance to radiation induced "bystander effects" studies. We have developed a system which employs single photon counting to measure the light emitted from samples irradiated under vacuum by a charged particle beam. The system uses a fast photomultiplier tube with a peak cathode response at 420 nm. It has been tested in a proof-of-principle experiment using polystyrene targets. Light output, as a result of irradiation, was measured. The luminescence yield appears to have a non-linear behavior with the incident ion fluence: it rises exponentially to an asymptotic value. The target was irradiated with beam energies varying from 1 to 2 MeV and showed saturation at or before an incident fluence rate of 3 × 1013 H+/cm2 s. The average saturation value for the photon output was found to be 40 × 106 cps. Some measurements were performed using filters to study the emission at specific wavelengths. In the case of filtered light measurements, the photon output was found to saturate at 28 × 103, 10 × 106, and 35 × 106 cps for wavelengths of 280 ± 5 nm, 320 ± 5 nm and 340 ± 5 nm respectively. The light output reaches a maximum value because of damage induced in the polymer. Our measurements indicate a "damage cross section" of the order of 10-14 cm2. The average radiant intensity was found to increase at wavelengths of 280 and 320 nm when the proton energy was increased. This was not found to occur at 340 nm. In conclusion, the light emission at specific wavelengths was found to depend upon the incident proton fluence and the proton energy. The wavelengths of the emitted light measured in this study have significance for the understanding of radiation induced bystander effects.

Ahmad, S. B.; McNeill, F. E.; Byun, S. H.; Prestwich, W. V.; Seymour, C.; Mothersill, C. E.

2012-10-01

110

INTERACTION OF LASER RADIATION WITH MATTER: Generation of a bleaching wave in an ST-50-1 glass ceramics induced by a Nd:YAG laser  

NASA Astrophysics Data System (ADS)

It is shown that upon exposing glass ceramics to laser radiation for which the initial polycrystalline phase is opaque, whereas the corresponding glass phase is transparent, the transparency oscillations can be produced due to the laser-induced phase transitions from the crystalline to amorphous state and vice versa, resulting in the propagation of a bleaching and darkening wave.

Veiko, V. P.; Novikov, B. Yu; Shakhno, E. A.; Yakovlev, E. B.

2009-01-01

111

Wet milling induced physical and chemical instabilities of naproxen nano-crystalline suspensions.  

PubMed

Wet-milling is the most common approach to formulate nano-crystalline suspensions. The effect of high intensity wet-milling on the physical and chemical stability of a poorly soluble drug was investigated. Naproxen (1%, w/v) was suspended in two different stabilizers (i.e. HPMC E15 and Tween 80) and stabilizer concentrations (0.2% or 0.6%, w/v) in distilled water. Wet-milling was performed at two different speeds (i.e. 3400rpm and 2000rpm) for four continuous hours. The milled samples were analyzed for physical and chemical instabilities. Wet-milling of naproxen-HPMC E15 at high milling intensity caused both physical and chemical instabilities as observed by particle size measurement and chemical analysis, respectively. The naproxen-Tween 80 formulations were stable regardless of milling intensity. Naproxen-HPMC E15 wet-milled samples, showed an IR peak shift suggesting strong bond formation or molecular interaction (i.e. amorphous phase). In addition, naproxen has a strong interaction with HPMC E15 as determined by MTDSC (i.e. melting point depression). The generation of amorphous phase at the naproxen-HPMC E15 crystal surface may be responsible for both aggregation and degradation during wet milling. Decarboxylated naproxen was identified as a degradation product. Milling intensity and/or selection of stabilizer/s are crucial for the stability of nano-crystalline suspensions. PMID:24614581

Kumar, Sumit; Burgess, Diane J

2014-05-15

112

Supersymmetry breaking induced by radiative corrections  

NASA Astrophysics Data System (ADS)

We show that simultaneous gauge and supersymmetry breaking can be induced by radiative corrections, à la Coleman-Weinberg. When a certain correlation among the superpotential parameters is present, a local supersymmetry-breaking minimum is induced in the effective potential of a gauge non-singlet field, in a region where the tree-level potential is almost flat. Supersymmetry breaking is then transmitted to the MSSM through gauge and chiral messenger loops, thus avoiding the suppression of gaugino masses characteristic of direct gauge mediation models. The use of a single field ensures that no dangerous tachyonic scalar masses are generated at the one-loop level. We illustrate this mechanism with an explicit example based on an SU(5) model with a single adjoint. An interesting feature of the scenario is that the GUT scale is increased with respect to standard unification, thus allowing for a larger colour Higgs triplet mass, as preferred by the experimental lower bound on the proton lifetime.

Bajc, Borut; Lavignac, Stéphane; Mede, Timon

2012-07-01

113

Non-targeted bystander effects induced by ionizing radiation  

Microsoft Academic Search

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

William F. Morgan; Marianne B. Sowa

2007-01-01

114

Induced radioactivity in Bevatron concrete radiation shielding blocks.  

National Technical Information Service (NTIS)

The Bevatron accelerated protons up to 6.2 GeV and heavy ions up to 2.1 GeV/amu. It operated from 1954 to 1993. Radioactivity was induced in some concrete radiation shielding blocks by prompt radiation. Prompt radiation is primarily neutrons and protons t...

G. C. Moeller R. J. Donahue

1994-01-01

115

[gamma]-radiation-induced changes in the chemical and physical structure of poly(ethylene terephthalate)  

SciTech Connect

Poly(ethylene terephthalate) (PET) film was irradiated with [gamma]-rays in air at doses from 0 to 620 Mrad, and at the rate of 0l8 to 1.0 Mrad/hr. Radiation-induced physical structure changes were studied by DMA and DSC measurements. Tensile properties were measured to find interrelationships with chemical and physical structure changes. Below 100 Mrad, PET shows little change in NMR and IR spectra. Fluorescence emission spectra, however, show the presence and increase of monohydroxy-substituted phenylene groups. This hydroxylation appears to stabilize the polymer. The phenylene group in PET also contributes to radiation-resistance. The amorphous-crystalline interfaces impede the penetration of oxygen and slow the oxidative chain scission. Between 100 and 215 Mrad, UV studies reveal that the rates of reaction begin to change rapidly. Chain scission appears to take place first in the interspherulitic amorphous regions and then in the intraspherulitic (interlamella) regions. [gamma]-Radiation-induced oxidative degradation shows aspects of both photolysis and of thermooxidative degradation (proton and carbon-13 NMR, and IR studies). It was concluded that the crystalline phase breaks down in to smaller crystallites, and these smaller crystallites grow in size by acting as nucleating sites. Tensile measurements show that throughout the range of irradiation studied the tensile strength at break and the percent elongation decrease. The tensile strength decreases uniformly and the percent elongation exhibits a more rapid decrease above 100 Mrad. The results of this study lead to the conclusion that [gamma]-radiation-induced oxidative degradation of PET involves products that are seen in both photolysis and thermooxidation.

Jin, Ho-Seon.

1992-01-01

116

Multiresonant two-photon-absorption-induced four wave mixing in crystalline rare earth insulators  

SciTech Connect

Coherent nonlinear optical generation of omega/sub 4/ = omega/sub 1/ + omega/sub 2/- omega/sub 3/ exhibits strong sharp intermediate (omega/sub 1/) and two-photon (omega/sub 1/ + omega /sub 2/) resonances in crystalline Tb(OH)/sub 3/ and LiTbF/sub 4/, providing a novel method for high resolution coherent measurement of both excited electronic configurations and intermediate 4f/sup n/ states of rare earth ions. New regions of the UV and VUV are thus made accessible to existing tuneable visible and near ultraviolet lasers. Selection of sharp features from broad overlapping absorptions, line narrowing due to phase matching selectivity, and coherent transient applications are discussed.

Cone, R.L.; Ender, D.A.; Otteson, M.S.; Fisher, P.L.; Friedman, J.M.; Guggenheim, H.J.

1982-01-01

117

Flow Induced Structures in Liquid Crystalline Polymers as Studied by Neutron Scattering  

NASA Astrophysics Data System (ADS)

Small angle neutron scattering has been utilized to examine the orientation of liquid crystalline polymer systems during and after the application of a flow field. Thermotropic systems show unique behavior including perpendicular orientation to the flow direction at low temperature and a temperature dependence of the molecular orientation within in the nematic regime. It is also found that the orientation is long-lived after the removal of the shear field in the thermotropic system. In lyotropic systems, however, an interesting dependence on solvent is found. The alignment behavior of poly(benzyl L-glutamate) (PBLG) in deuterated benzyl alcohol (DBA) differs significantly from the alignment of PBLG in deuterated m-cresol (DMC) during shear and upon shear cessation. This is unexpected, as DMC is an isomer of DBA. Possible explanations for this behavior will be discussed.

Dadmun, Mark

2000-03-01

118

Changing bioperformance of TiO2 amorphous nanotubes as an effect of inducing crystallinity.  

PubMed

Controlled-diameter TiO(2) nanotubes were obtained by electrochemical anodizing of two different substrates (Ti and Ti6Al7Nb) in an aqueous electrolyte. As-formed TiO(2) nanotubes are amorphous and by subjecting to thermal treatments, the structure becomes crystalline. An optimal thermal treatment with a specific anatase/rutile ratio was chosen, determined from X-ray diffraction (XRD). The electrochemical behaviour of annealed and as-formed samples was followed with Tafel plots and Electrochemical impedance spectroscopy (EIS), while surface analysis involved scanning electron microscopy (SEM) and contact angle measurements (CA). Annealed samples have a more hydrophilic character than as-formed as well as a better stability in bioliquids. Such behaviour of annealed samples is connected with a better biocompatibility expressed in terms of cell morphology and gene expression of bone specific markers obtained from Reverse Transcription Polymerase Chain Reaction (RT-PCR). PMID:22341625

Mazare, A; Dilea, M; Ionita, D; Titorencu, I; Trusca, V; Vasile, E

2012-10-01

119

Treatment of radiation-induced cystitis with hyperbaric oxygen  

SciTech Connect

The effects of hyperbaric oxygen on radiation cystitis have been documented in 3 patients with radiation-induced hemorrhagic cystitis refractory to conventional therapy. Cessation of gross hematuria and reversal of cystoscopic bladder changes were seen in response to a series of hyperbaric oxygen treatments of 2 atmosphere absolute pressure for 2 hours. To our knowledge this is the first report of cystoscopically documented healing of radiation-induced bladder injury.

Weiss, J.P.; Boland, F.P.; Mori, H.; Gallagher, M.; Brereton, H.; Preate, D.L.; Neville, E.C.

1985-08-01

120

Silica-based cerium (III) chloride nanoparticles prevent the fructose-induced glycation of ?-crystallin and H?O?-induced oxidative stress in human lens epithelial cells.  

PubMed

This study aimed to investigate whether silica-cerium (III) chloride (CeCl3) nanoparticles could inhibit the formation of advanced glycation end-products (AGEs) and reduce oxidative stress. Silica-CeCl3 nanoparticles were synthesised by adsorption and embedment with micro-silica materials, forming uniform nanoparticles with a diameter of approximately 130 nm. Chaperone activity assays and AGEs formation assays, and intracellular reactive assays were adopted in this study to evaluate CeCl3 nanoparticles effect. UV-visible spectrometry showed that silica-CeCl3 nanoparticles at low concentrations rapidly formed tentatively stable conjugations with ?-crystallin, greatly enhancing the chaperone activity of ?-crystallin. Moreover, silica-CeCl3 nanoparticles markedly inhibited the fructose-induced glycation of ?-crystallin, showing an advantage over the control drugs aminoguanidine and carnosine. Silica-CeCl3 nanoparticles also reduced intracellular reactive oxygen species production and restored glutathione levels in H2O2-treated human lens epithelial cells. These findings suggest that silica-CeCl3 may be used as a novel agent for the prevention of cataractogenesis. PMID:23828754

Yang, Jin; Cai, Lei; Zhang, Sen; Zhu, Xiangjia; Zhou, Peng; Lu, Yi

2014-03-01

121

Swelling characteristics of konjac glucomannan superabsobent synthesized by radiation-induced graft copolymerization  

NASA Astrophysics Data System (ADS)

Graft copolymerization of konjac glucomannan (KGM) and acrylic acid was induced by 60Co-? irradiation at room temperature. The effects of radiation dose and monomer-to-KGM ratio on grafting yield and equilibrium water absorbency were investigated. The KGM-based superabsorbent polymer (KSAP) could absorb water 625 times of its dry weight when the radiation dose was 5.0 kGy and monomer-to-KGM ratio was 5. The structure of KSAP was characterized by FTIR, XRD, and SEM. KSAP showed a lower crystallinity than KGM. The porous microstructure of KSAP was revealed by SEM. The diffusion mechanism of water in the hydrogel is consistent with the anomalous diffusion model. Cations, especially multivalent cations, greatly reduced water absorbency of KSAP. Rising temperature, acidic or basic solutions are not favorable for the swelling of KSAP.

Wu, Jia; Deng, Xiao; Lin, Xiangyang

2013-02-01

122

Formation of crystalline ?-Al2O3 induced by variable substrate biasing during reactive magnetron sputtering  

NASA Astrophysics Data System (ADS)

Reactive magnetron sputtering is a widely used technique to deposit various materials such as oxides and nitrides with a superior control of morphology and stoichiometry. The adjustment of the film properties at a given substrate temperature is believed to be affected by the average energy per incorporated atom during film growth, which is controlled by the ion-to-neutral ratio in the film forming growth flux and the energy of the incident ions. This concept is tested for alumina growth in an rf-magnetron discharge by keeping , the average energy of the incident ions Eions, and the ion-to-neutral flux ratio constant, but varying only the energy distribution of the incident ions (ion energy distribution-IED). The influence of the IED on film growth is monitored by observing the transition of the films between x-ray amorphous Al2O3 to ?-Al2O3. The results reveal that the substrate temperature necessary for the transition to ?-crystalline films can be lowered by almost 100 °C, when the maximum energy of the incident ions is kept at 100 eV, while maintaining the energy per incorporated atom at 11 eV. This result is compared with TRIM calculations for the collision cascades of impacting ions.

Prenzel, M.; Kortmann, A.; von Keudell, A.; Nahif, F.; Schneider, J. M.; Shihab, M.; Brinkmann, R. P.

2013-02-01

123

Protective immunity to UV radiation-induced skin tumours induced by skin grafts and epidermal cells  

Microsoft Academic Search

There is little evidence that cutaneous dendritic cells (DC), including epidermal Langerhans cells (LC), can induce immunity to UV radiation (UVR)-induced skin tumours. Here, it is shown that cells within skin can induce protective antitumour immunity against a UVR-induced fibrosarcoma. Transplantation of the skin overlying subcutaneous tumours onto naïve recipients could induce protective antitumour immunity, probably because the grafting stimulated

Ronald Sluyter; Kylie S Yuen; Gary M Halliday

2001-01-01

124

DNA fragmentation induced by ionizing radiation - Atomic Force Microscopy study .  

NASA Astrophysics Data System (ADS)

DNA as a carrier of genetic information is considered to be the critical target for radiation induced damage Especially severe are DNA double-strand breaks DSBs formed when breaks occur in both strands of the molecule The DSBs production is determined by the spatial distribution of ionization events dependent on the physical properties of the energy deposition and the chemical environment of the DNA According to theoretical predictions high LET charged particle radiation induces lesions in close proximity forming so called clustered damage in the DNA Atomic Force Microscopy AFM was newly established as a technique allowing the direct visualization of DNA fragments resulting from DSBs induced in small DNA molecules plasmids by ionizing radiation We have used AFM to visualize the DNA fragmentation induced by heavy ions high LET radiation and to compare it to the fragmentation pattern obtained after X-rays low LET radiation Plasmid supercoiled DNA was irradiated in vitro with X-rays and 3 9 MeV u Ni ions within a dose range 0 -- 3000 Gy Afterwards the samples were analyzed using AFM which allowed the detection and length measurement of individual fragments with a nanometer resolution Recording of the length of the induced fragments allowed to distinguish between molecules broken by a single DSB or by multiple DSBs The fragment length distributions were derived for different doses and different radiation qualities The first results of the measurement of radiation-induced DNA fragmentation show an influence of radiation quality on

Gudowska-Nowak, E.; Psonka, K.; Elsaesser, Th.; Brons, S.; Taucher-Scholz, G.

125

Radiation induces senescence and a bystander effect through metabolic alterations.  

PubMed

Cellular senescence is a state of irreversible growth arrest; however, the metabolic processes of senescent cells remain active. Our previous studies have shown that radiation induces senescence of human breast cancer cells that display low expression of securin, a protein involved in control of the metaphase-anaphase transition and anaphase onset. In this study, the protein expression profile of senescent cells was resolved by two-dimensional gel electrophoresis to investigate associated metabolic alterations. We found that radiation induced the expression and activation of glyceraldehyde-3-phosphate dehydrogenase that has an important role in glycolysis. The activity of lactate dehydrogenase A, which is involved in the conversion of pyruvate to lactate, the release of lactate and the acidification of the extracellular environment, was also induced. Inhibition of glycolysis by dichloroacetate attenuated radiation-induced senescence. In addition, radiation also induced activation of the 5'-adenosine monophosphate-activated protein kinase (AMPK) and nuclear factor kappa B (NF-?B) pathways to promote senescence. We also found that radiation increased the expression of monocarboxylate transporter 1 (MCT1) that facilitates the export of lactate into the extracellular environment. Inhibition of glycolysis or the AMPK/NF-?B signalling pathways reduced MCT1 expression and rescued the acidification of the extracellular environment. Interestingly, these metabolic-altering signalling pathways were also involved in radiation-induced invasion of the surrounding, non-irradiated breast cancer and normal endothelial cells. Taken together, radiation can induce the senescence of human breast cancer cells through metabolic alterations. PMID:24853433

Liao, E-C; Hsu, Y-T; Chuah, Q-Y; Lee, Y-J; Hu, J-Y; Huang, T-C; Yang, P-M; Chiu, S-J

2014-01-01

126

Radiation induces senescence and a bystander effect through metabolic alterations  

PubMed Central

Cellular senescence is a state of irreversible growth arrest; however, the metabolic processes of senescent cells remain active. Our previous studies have shown that radiation induces senescence of human breast cancer cells that display low expression of securin, a protein involved in control of the metaphase–anaphase transition and anaphase onset. In this study, the protein expression profile of senescent cells was resolved by two-dimensional gel electrophoresis to investigate associated metabolic alterations. We found that radiation induced the expression and activation of glyceraldehyde-3-phosphate dehydrogenase that has an important role in glycolysis. The activity of lactate dehydrogenase A, which is involved in the conversion of pyruvate to lactate, the release of lactate and the acidification of the extracellular environment, was also induced. Inhibition of glycolysis by dichloroacetate attenuated radiation-induced senescence. In addition, radiation also induced activation of the 5?-adenosine monophosphate-activated protein kinase (AMPK) and nuclear factor kappa B (NF-?B) pathways to promote senescence. We also found that radiation increased the expression of monocarboxylate transporter 1 (MCT1) that facilitates the export of lactate into the extracellular environment. Inhibition of glycolysis or the AMPK/NF-?B signalling pathways reduced MCT1 expression and rescued the acidification of the extracellular environment. Interestingly, these metabolic-altering signalling pathways were also involved in radiation-induced invasion of the surrounding, non-irradiated breast cancer and normal endothelial cells. Taken together, radiation can induce the senescence of human breast cancer cells through metabolic alterations.

Liao, E-C; Hsu, Y-T; Chuah, Q-Y; Lee, Y-J; Hu, J-Y; Huang, T-C; Yang, P-M; Chiu, S-J

2014-01-01

127

The influence of crystallinity degree on the glycine decomposition induced by 1 MeV proton bombardment in space analog conditions.  

PubMed

Glycine is the simplest proteinaceous amino acid and is present in all life-forms on Earth. In aqueous solutions, it appears mainly as zwitterion glycine (+NH3CH2COO-); however, in solid phase, it may be found in amorphous or crystalline (?, ?, and ?) forms. The crystalline forms differ from each other by the packing of zwitterions in the unitary cells and by the number of intermolecular hydrogen bonds. This molecular species has been extensively detected in carbonaceous meteorites and was recently observed in the cometary samples returned to Earth by NASA's Stardust spacecraft. In space, glycine is exposed to several radiation fields at different temperatures. We present an experimental study on the destruction of zwitterionic glycine crystals at room temperature by 1 MeV protons, in which the dependence of the destruction rates of the ?-glycine and ?-glycine crystals on bombardment fluence is investigated. The samples were analyzed in situ by Fourier transform infrared spectrometry at different proton fluences. The experiments occurred under ultrahigh vacuum conditions at the Van de Graaff accelerator lab at the Pontifical Catholic University at Rio de Janeiro (PUC-Rio), Brazil. For low fluences, the dissociation cross section of ?-glycine was observed to be 2.5×10(-14) cm2, a value roughly 5 times higher than the dissociation cross section found for ?-glycine. The estimated half-lives of ?-glycine and ?-glycine zwitterionic forms extrapolated to the Earth orbit environment are 9×10(5) and 4×10(6) years, respectively. In the diffuse interstellar medium the estimated values are 1 order of magnitude lower. These results suggest that pristine interstellar ?-glycine is the one most likely to survive the hostile environments of space radiation. A small feature around 1650-1700?cm(-1), tentatively attributed to an amide functional group, was observed in the IR spectra of irradiated samples, suggesting that cosmic rays may induce peptide bond synthesis in glycine crystals. Combining this finding with the fact that this form has the highest solubility among the other glycine polymorphs, we suggest that ?-glycine is the one most likely to have produced the first peptides on primitive Earth. PMID:23249407

Pilling, Sergio; Mendes, Luiz A V; Bordalo, Vinicius; Guaman, Christian F M; Ponciano, Cássia R; da Silveira, Enio F

2013-01-01

128

Effect of radiation induced crosslinking and degradation of ETFE films  

NASA Astrophysics Data System (ADS)

In this study the ETFE film with 125 ?m of thickness was placed inside a nylon bag and filled with either acetylene, nitrogen or oxygen. Following the procedure, the samples were irradiated at 5, 10 and 20 kGy. The physical and chemical properties of the modified and pristine films were evaluated by rheological and thermal analyses (TG and DSC), X-ray diffraction (XRD) and infrared spectroscopy (IR-ATR). In rheological analysis the storage modulus (G') indicates opposite profiles when the atmospheres (acetylene and oxygen) are evaluated according to the absorbed dose. For the samples submitted to radiation under oxygen atmosphere it is possible to observe the degradation process with the low levels of the storage modulus. The changes in the degree of crystallinity were verified in all modified samples when compared to the pristine polymer and this behavior was confirmed by DSC analysis. A decrease in the intensity of crystalline peak by X-ray diffraction was observed.

Zen, H. A.; Ribeiro, G.; Geraldes, A. N.; Souza, C. P.; Parra, D. F.; Lugão, A. B.

2013-03-01

129

Radiation-induced segregation in candidate fusion-reactor alloys  

SciTech Connect

The effect of radiation on surface segregation of minor and impurity elements has been studied in four candidate fusion reactor alloys. Radiation induced surface segregation of phosphorus was found in both 316 type stainless steel and in Nimonic PE-16. Segregation and depletion of the other alloying elements in 316 stainless steel agreed with that reported by other investigators. Segregation of nitrogen in ferritic HT-9 was enhanced by radiation but no phosphorus segregation was detected. No significant radiation enhanced or induced segregation was observed in a Ti-6Al-4V alloy. The results indicate that radiaton enhanced grain boundary segregation could contribute to the embrittlement of 316 SS and PE-16.

Brimhall, J.L.; Baer, D.R.; Jones, R.H.

1981-07-01

130

Acid-induced dissociation of alpha A- and alpha B-crystallin homopolymers.  

PubMed Central

Homopolymers were constructed from the alpha A and alpha B polypeptides isolated from the lens protein alpha-crystallin. As the pH is lowered from 7.0 to 3.4, these homopolymers dissociate to smaller species with molecular masses ranging from 80 to 250 kDa for the alpha A and around 140 kDa for the alpha B dissociation products. The pKa for this dissociation was 3.8 +/- 0.2 for alpha A and 4.1 +/- 0.1 for alpha B homopolymers. Further decreases in pH, to 2.5, resulted in the presence of only denatured alpha B polypeptides, whereas the alpha A dissociation products remained intact. Fractionation of the acid dissociation products from the alpha A homopolymer at pH 2.5 yielded stable species with molecular masses of 220 +/- 30, 160 +/- 20, and 90 +/- 10 kDa. The majority of the population at acid pH consisted of the 160 kDa species. Conformational analysis of these species revealed that most of the secondary structure of the original alpha A homopolymer was retained but that the tertiary structure was perturbed. Fluorescence quenching and energy transfer measurements suggested that the molecule had undergone acid expansion, with the greatest perturbation observed in the smallest particles. The results from this work suggest that alpha A homopolymers are heterogeneous populations of aggregates of a "monomeric" molecule with a molecular mass of 160 kDa. This "monomeric" molecule may be formed from the association of two tetrameric units.

Stevens, A; Augusteyn, R C

1993-01-01

131

Response to chemotherapy of a radiation-induced glioblastoma multiforme  

Microsoft Academic Search

Summary\\u000a Background  Radiation-induced glioblastoma multiforme (GBM) is particularly resistant to treatment and therapeutic options are limited.\\u000a We report a patient with a radiation-induced GBM who had a complete response to carmustine and survived for 44 months.\\u000a \\u000a \\u000a \\u000a Patients and Methods  Case report of a 38-year-old man with a radiation-induced GBM that responded to carmustine.\\u000a \\u000a \\u000a \\u000a Results  Our patient developed a left occipital GBM 35 years after a

Linda Nicolardi; Lisa M. DeAngelis

2006-01-01

132

Formation and annihilation of intrinsic defects induced by electronic excitation in high-purity crystalline SiO{sub 2}  

SciTech Connect

Formation and thermal annihilation of intrinsic defects in {alpha}-quartz were examined using high-purity samples, while minimizing the contributions of reactions involving metallic impurities. Electronic excitation with {sup 60}Co {gamma}-rays was employed to avoid radiation-induced amorphization. The results clearly show that formation of oxygen vacancies (Si-Si bonds) as a result of decomposition of regular Si-O-Si bonds (Frenkel process) is the dominant intrinsic defect process. Compared with amorphous SiO{sub 2}, in {alpha}-quartz, the formation yield of Si-Si bonds is an order of magnitude smaller, the 7.6 eV optical absorption band is less broadened, and their thermal annihilation is complete at a lower temperature, around the {alpha}-{beta} quartz transition. In contrast, radiation-induced interstitial oxygen atoms practically do not form interstitial oxygen molecules.

Kajihara, Koichi [Department of Applied Chemistry, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji 192-0397 (Japan); Skuja, Linards [Institute of Solid State Physics, University of Latvia, Kengaraga iela 8, LV1063 Riga (Latvia); Hosono, Hideo [Materials and Structures Laboratory and Frontier Research Center, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan)

2013-04-14

133

Formation and annihilation of intrinsic defects induced by electronic excitation in high-purity crystalline SiO2  

NASA Astrophysics Data System (ADS)

Formation and thermal annihilation of intrinsic defects in ?-quartz were examined using high-purity samples, while minimizing the contributions of reactions involving metallic impurities. Electronic excitation with 60Co ?-rays was employed to avoid radiation-induced amorphization. The results clearly show that formation of oxygen vacancies (Si-Si bonds) as a result of decomposition of regular Si-O-Si bonds (Frenkel process) is the dominant intrinsic defect process. Compared with amorphous SiO2, in ?-quartz, the formation yield of Si-Si bonds is an order of magnitude smaller, the 7.6 eV optical absorption band is less broadened, and their thermal annihilation is complete at a lower temperature, around the ?-? quartz transition. In contrast, radiation-induced interstitial oxygen atoms practically do not form interstitial oxygen molecules.

Kajihara, Koichi; Skuja, Linards; Hosono, Hideo

2013-04-01

134

Microscopic Effects of Shock Metamorphism in Crystalline Rocks Correlated With Shock Induced Changes in Density, Haughton Impact Structure  

NASA Astrophysics Data System (ADS)

Asteroid and comet impacts are an important geological process on all solid planetary bodies, including Earth, and involve pressures and temperatures that may reach several hundred GPa and several thousand K [1] over very limited spatial and temporal scales. This results in shock metamorphism and alters the target material on both megascopic and microscopic scales [2]. Many shock metamorphic features are unique to hypervelocity impact environments and are, therefore, diagnostic of such an event [1,2]. Of particular interest for this study is the effect of hypervelocity impact on the density of the target material. In the case of crystalline target rocks, shock metamorphism results in an increase of pore space and impact induced fractures which act to decrease the density. The Haughton impact structure is a well-preserved late Eocene (39 ± 2 Ma) complex impact structure, situated near the western end of Devon Island (75°22'N, 89°41'W) [3]. The geology of the area consists of a sedimentary sequence unconformably overlying crystalline Precambrian gneisses of the Canadian Shield. Since the impact, Devon Island has remained tectonically stable and Haughton remains well-preserved despite being subjected to several glaciations. The excellent preservation of the structure is largely due to the primarily cold and relatively dry environment that has existed in the Arctic since the Eocene [3]. Samples of crystalline material were collected from 36 sites within the impact breccia unit of the Haughton impact structure. These samples display a wide range of density and physical appearance. The type of shock effect(s) created depends upon the pressures and temperatures involved as well as the composition, density and material's location in the target. The samples found in the Haughton impact structure show a wide range of shock effects and thus were exposed to a variety of different conditions likely due to their in-situ positions relative to the impact. Polished thin sections from a representative selection of shocked and unshocked Precambrian gneiss from the Haughton impact structure were investigated in transmitted light with a petrographic microscope and each sample was assigned a shock level based on the identification of shock features. Features identified include kink banding in mica, planar deformation features in quarts and feldspar, and partial or complete melting of various minerals. The density of each sample was also measured. Preliminary results suggest a correlation between decreasing density and increasing shock level. These results may be important not only for understanding shock metamorphism, but also for astrobiology. Impact- induced density decreases in crystalline rocks present opportunities for microbial colonization that would not exist otherwise [4]. The colonization of the shocked material in craters represents a potential mechanism for pioneer organisms to invade an impact structure in the earliest stages of post-impact primary succession. This is a possible mechanism by which microbes may gain a foothold on planetary surfaces that do not have other hospitable habitats. This may be of particular relevance to Mars [4]. [1] Langenhorst, F., Bulletin of the Czech Geo. Survey, 2002. 77, (4): p. 265-282. [2] Therriault, A.M. et al. Bul- letin of the Czech Geo. Survey, 2002. 77, (4): p. 253-263. [3] Stöffler, D. (1971) Journal of Geo-physical Research, 79, (23) [4] Cockell, C.S. et al. Met. & Pl. Sci., 2002. 37, p. 1287-1298.

Singleton, A. C.; Osinski, G.; Moser, D.

2009-05-01

135

Ion-induced synthesis of uniform single-crystalline sulphide-based quaternary-alloy hexagonal nanorings for highly efficient photocatalytic hydrogen evolution.  

PubMed

Uniform single-crystalline quaternary sulphide nanoring photocatalysts are synthesized via the copper-ion-induced Kirkendall effect and is followed by a cation exchange reaction. The obtained Cu(2+)-doped ZnIn(2)S(4) nanorings show highly preserved morphology, and demonstrate high visible-light-driven photocatalytic activity for H(2) evolution in water splitting. PMID:23447427

Hu, Peng; Pramana, Stevin Snellius; Cao, Shaowen; Ngaw, Chee Keong; Lin, Jingdong; Loo, Say Chye Joachim; Tan, Timothy Thatt Yang

2013-05-14

136

Amorphization induced by chemical disorder in crystalline NiZr2: A molecular-dynamics study based on an n-body potential  

NASA Astrophysics Data System (ADS)

We present the first molecular-dynamics study of the amorphization of a crystalline alloy (NiZr2) induced by chemical disorder. We used a n-body potential in conjunction with isobaric-isothermal molecular dynamics. The behavior of the pair distribution function suggests that the instability leading to the amorphous state is a first-order phase transformation.

Massobrio, C.; Pontikis, V.; Martin, G.

1989-03-01

137

Dose-dependent radiation-induced hypotension in the canine  

SciTech Connect

Radiation-induced early transient incapacitation (ETI) is often accompanied by severe systemic hypotension. However, postradiation hypotension does not occur with equal frequency in all species and is not reported with consistency in the canine. In an attempt to clarify the differences in reported canine post-radiation blood pressures, canine systemic blood pressures were determined both before and after exposure to gamma radiation of either 80 or 100 Gy. Data obtained from six sham-radiated beagles and 12 radiated beagles indicated that 100-Gy, whole-body, gamma radiation produced a decrease in systemic mean blood pressure while 80-Gy, whole-body, gamma radiation did not. Analysis of this data could be consistent with a quantal response to a gamma radiation dose between 80 Gy and 100 Gy.

Cockerham, L.G.; Hampton, J.D.; Doyle, T.F.

1986-01-01

138

Reorientation of the crystalline planes in confined single crystal nickel nanorods induced by heavy ion irradiation  

SciTech Connect

In a recent letter Tyagi et al. [Appl. Phys. Lett. 86, 253110 (2005)] have reported the special orientation of nickel planes inside multiwalled carbon nanotubes (MWCNTs) with respect to the tube axis. Heavy ion irradiation has been performed with 1.5 MeV Au{sup 2+} and 100 MeV Au{sup 7+} ions on these nickel filled MWCNTs at fluences ranging from 10{sup 12} to 10{sup 15} ions/cm{sup 2} at room temperature. Ion-induced modifications have been studied using high-resolution transmission electron microscopy. The diffraction pattern and the lattice imaging showed the presence of ion-induced planar defects on the tube walls and completely amorphized encapsulated nickel nanorods. The results are discussed in terms of thermal spike model.

Misra, Abha; Tyagi, Pawan K.; Rai, Padmnabh; Misra, D. S.; Ghatak, Jay; Satyam, P. V.; Avasthi, D. K. [Physics Department, IIT Bombay, Powai, Mumbai 400076 (India); Institute of Physics, Sachivalaya Marg, Bhubaneswar 751005 (India); Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India)

2006-08-28

139

Reorientation of the crystalline planes in confined single crystal nickel nanorods induced by heavy ion irradiation  

NASA Astrophysics Data System (ADS)

In a recent letter Tyagi et al. [Appl. Phys. Lett. 86, 253110 (2005)] have reported the special orientation of nickel planes inside multiwalled carbon nanotubes (MWCNTs) with respect to the tube axis. Heavy ion irradiation has been performed with 1.5 MeV Au2+ and 100 MeV Au7+ ions on these nickel filled MWCNTs at fluences ranging from 1012 to 1015 ions/cm2 at room temperature. Ion-induced modifications have been studied using high-resolution transmission electron microscopy. The diffraction pattern and the lattice imaging showed the presence of ion-induced planar defects on the tube walls and completely amorphized encapsulated nickel nanorods. The results are discussed in terms of thermal spike model.

Misra, Abha; Tyagi, Pawan K.; Rai, Padmnabh; Misra, D. S.; Ghatak, Jay; Satyam, P. V.; Avasthi, D. K.

2006-08-01

140

Defect-induced ferromagnetism in crystalline SrTiO 3  

NASA Astrophysics Data System (ADS)

In this work it is shown that ion irradiation of high-quality SrTiO 3 single crystals can lead to room-temperature ferromagnetism. Structural analysis revealed a polycrystalline SrTiO 3 layer, Sr 2Ti 6O 13, or Ruddlesden-Popper like secondary phase at the sample surface induced by the irradiation. The lack of any measurable ferromagnetic secondary phases suggests defects are the origin of the observed ferromagnetic signal.

Potzger, K.; Osten, J.; Levin, A. A.; Shalimov, A.; Talut, G.; Reuther, H.; Arpaci, S.; Bürger, D.; Schmidt, H.; Nestler, T.; Meyer, D. C.

2011-06-01

141

Modification of Synthetic Fibers by Radiation-Induced Grafting.  

National Technical Information Service (NTIS)

The present report describes studies to modify properties of synthetic fibers by radiation-induced grafting technique. This technique was employed since it is considered to be generally applicable to the grafting of a radically polymerizable monomer onto ...

K. Kaji

1981-01-01

142

Radiation-induced xerostomia: pathophysiology, clinical course and supportive treatment  

Microsoft Academic Search

Xerostomia, or oral dryness, is one of the most common complaints experienced by patients who have had radiotherapy of the\\u000a oral cavity and neck region. The hallmarks of radiation-induced damage are acinar atrophy and chronic inflammation of the\\u000a salivary glands. The early response, resulting in atrophy of the secretory cells without inflammation might be due to radiation-induced\\u000a apoptosis. In contrast,

H.-J. Guchelaar; A. Vermes; J. H. Meerwaldt

1997-01-01

143

Defects induced in fluorides and oxides by VUV radiation  

Microsoft Academic Search

Irradiation effects of monochromatic VUV were studied in some broad band crystals such as alkaline-earth and perovskite-type fluorides as well as metal oxides. The irradiations were carried out at RT and at LNT and the thermal stability of some radiation-induced defects was studied. Results were compared to effects induced in the same samples by X or radiation. The various types

N. Kristianpoller; D. Weiss; R. Chen

2005-01-01

144

Repair Machinery for Radiation-Induced DNA Damage.  

National Technical Information Service (NTIS)

Understanding the repair mechanisms for ionizing radiation (IR) - induced DNA damage and having prior knowledge of a patient' 5 1K-specific repair capacity will help determine which patients will be most responsive to radiation therapy and design more aff...

D. Wilson

2001-01-01

145

The radiation-induced lesions which trigger the bystander effect  

Microsoft Academic Search

The ionizing radiation induced bystander effect is initiated by damage to a cellular molecule which then gives rise to a signal exported to other cells. The nature of this damage is considered with the understanding that it may not be the same as that responsible for the traditional cellular effects of radiation. Consideration is give to amounts of endogenous damage

John F Ward

2002-01-01

146

Hyperbaric Oxygen Therapy for Radiation-induced Optic Neuropathy  

Microsoft Academic Search

Introduction: Radiation-induced optic neuropathy (RON) is an infrequent but devastating consequence of radiation exposure to the visual pathways, usually following months to years after the treatment of paranasal or intracranial tumours. Hyperbaric oxygen (HBO) therapy is one of several therapies that have been tried for this condition. The purpose of this review is to describe the clinical characteristics of RON,

Richard L Levy; Neil R Miller

147

Space-radiation-induced photon luminescence of the Moon  

Microsoft Academic Search

We report on the results of a continuing study of the photon luminescence of the Moon induced by Galactic Cosmic Rays (GCRs) and space radiation from the Sun, using the Monte Carlo program FLUKA. Understanding the space radiation environment is critical to future exploration of the Moon, and this includes photons. The model of the lunar surface is taken to

K. T. Lee; T. L. Wilson

2009-01-01

148

Radiation induced sarcoma following treatment of breast cancer.  

PubMed

The occurrence of radiation induced sarcoma following treatment of breast cancer is rare. It has an average latency of ten years and it correlates with the dose and technique of radiation. The prognosis is poor due to delay in diagnosis. We present a case where a female patient developed a chondrosarcoma of sternoclavicular joint 19 years after radiotherapy for breast cancer. PMID:10921225

Pandey, K K; Kumar, R; Goel, A; Saharia, A

1999-01-01

149

Radiation-Induced Cellular Adaptive Response.  

National Technical Information Service (NTIS)

One aspect of the present invention relates to a method for determining an adaptive response of a tumor during radiation therapy. A second aspect of the present invention relates to a method for determining a substantially optimal dose of radiation therap...

B. P. Engelward

2005-01-01

150

Probing the photothermally induced phase transitions in single-crystalline vanadium dioxide nanobeams  

NASA Astrophysics Data System (ADS)

Using Raman spectroscopy, we demonstrated photothermally induced crystallographic phase transitions of vanadium dioxide (VO2) nanobeams clamped to and free-standing on a substrate. Compared to the temperature-dependent Raman measurements, the laser-power-dependent Raman characteristics provide substantial evidence for the photothermal origin of the phase transitions of the VO2 nanobeams. The laser power necessary to cause phase transitions in the free-standing nanobeam was approximately eight times smaller than the laser power used in the substrate-clamped nanobeam. Our study will enhance the understanding of the complex phase transitions of strongly correlated oxides and thereby provide a foundation for engineering desirable properties in novel devices.

Chang, Sung-Jin; Hong, Woong-Ki; Kim, Hae Jin; Lee, Jin Bae; Yoon, Jongwon; Ko, Heung Cho; Huh, Yun Suk

2013-08-01

151

Protection from radiation-induced pneumonitis using cerium oxide nanoparticles.  

PubMed

In an effort to combat the harmful effects of radiation exposure, we propose that rare-earth cerium oxide (CeO(2)) nanoparticles (free-radical scavengers) protect normal tissue from radiation-induced damage. Preliminary studies suggest that these nanoparticles may be a therapeutic regenerative nanomedicine that will scavenge reactive oxygen species, which are responsible for radiation-induced cell damage. The effectiveness of CeO(2) nanoparticles in radiation protection in murine models during high-dose radiation exposure is investigated, with the ultimate goal of offering a new approach to radiation protection, using nanotechnology. We show that CeO(2) nanoparticles are well tolerated by live animals, and they prevent the onset of radiation-induced pneumonitis when delivered to live animals exposed to high doses of radiation. In the end, these studies provide a tremendous potential for radioprotection and can lead to significant benefits for the preservation of human health and the quality of life for humans receiving radiation therapy. PMID:19285453

Colon, Jimmie; Herrera, Luis; Smith, Joshua; Patil, Swanand; Komanski, Chris; Kupelian, Patrick; Seal, Sudipta; Jenkins, D Wayne; Baker, Cheryl H

2009-06-01

152

Microstructure and magnetic disorder induced by nanoindentation in single-crystalline Fe  

NASA Astrophysics Data System (ADS)

Using molecular dynamics simulation, we study nanoindentation into an Fe (100) surface. We use the so-called magnetic interaction potentials provided by Dudarev and Derlet [J. Phys.: Condens. Matter 17, 7097 (2005), 10.1088/0953-8984/17/44/003] and Chiesa et al. [J. Phys.: Condens. Matter 23, 206001 (2011), 10.1088/0953-8984/23/20/206001] in three different parametrizations; these allow us to extract information about the local magnetic moments from the molecular-dynamics simulation. Our simulations are performed at low temperature; the simulation cell is assumed to consist of a single ferromagnetic domain. Material hardness as well as the density of dislocations generated coincide satisfactorily with previous studies using conventional potentials. We observe the generation of both b =1/2<111> and b =<100> dislocations, which contribute to the plastic deformation. Besides dislocations, the induced microstructure features twins and vacancies. The local magnetic moments change considerably due to the strain field induced by the developing microstructure and assume values between 83 and 112% of the equilibrium bulk value in Fe. These changes are, however, quite localized and quickly decay away from the highly strained regions of dislocation cores.

Wang, Binjun; Gao, Yu; Urbassek, Herbert M.

2014-03-01

153

Pressure-induced depolarization and resonance in Raman scattering of single-crystalline boron carbide  

SciTech Connect

We report polarized and resonant Raman scattering of single-crystal boron carbide (B{sub 4}C) at high pressures. Significant intensity enhancements of 270 and 1086 cm{sup -1} Raman bands of B{sub 4}C have been observed at quasihydrostatic pressures higher than approx20 GPa. The pressure-induced intensity change of the 1086 cm{sup -1} band is mainly due to the resonance between excitation energy and electronic transition, whereas the intensity change of 270 cm{sup -1} band is caused by the depolarization effect. Importantly, the first-order phase transition has not been found at high quasihydrostatic pressures and all the Raman intensity changes along with the corresponding high-pressure lattice distortion can be recovered during unloading.

Guo Junjie; Zhang Ling; Fujita, Takeshi; Chen Mingwei [WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Goto, Takashi [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan)

2010-02-01

154

Radiation-induced decomposition of explosives under extreme conditions  

Microsoft Academic Search

We present high-pressure and high temperature studies of the synchrotron radiation-induced decomposition of powder secondary high explosives pentaerythritol tetranitrate (PETN) and 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) using white beam synchrotron radiation at the 16 BM-B and 16 BM-D sectors of the HP-CAT beamline at the Advanced Photon Source. The radiation-induced decomposition rate TATB showed dramatic slowing with pressure up to 26.6GPa (the highest

Hubertus Giefers; Michael Pravica; Wenge Yang; Peter Liermann

2008-01-01

155

Radiation-induced coronary artery disease  

SciTech Connect

This report describes three patients who developed myocardial infarction at an untimely age, 4 to 12 years after radiation therapy for Hodgkin's disease. These cases lend credence to the cause and effect relation of such therapy to coronary artery disease.

Dunsmore, L.D.; LoPonte, M.A.; Dunsmore, R.A.

1986-07-01

156

Radiation-induced changes in carboxymethylated chitosan  

Microsoft Academic Search

This study focuses on the radiation effect of ?-ray on carboxymethylated chitosan (CM-chitosan) in solid state. The changes in molecular weight of CM-chitosan with absorbed dose were monitored by viscosity method. Experimental results indicated that random chain scissions took place under irradiation. Radiation chemical yield (Gd) of CM-chitosan in solid state with N2-saturated was 0.49, which showed CM-chitosan has high

Ling Huang; Jing Peng; Maolin Zhai; Jiuqiang Li; Genshuan Wei

2007-01-01

157

Cosmic Microwave Background Radiation Anisotropy Induced by Cosmic Strings  

Microsoft Academic Search

We report on a current investigation of the anisotropy pattern induced by cosmic strings on the cosmic microwave background radiation (MBR). We have numerically evolved a network of cosmic strings from a redshift of $Z = 100$ to the present and calculated the anisotropies which they induce. Based on a limited number of realizations, we have compared the results of

B. Allen; R. R. Caldwell; E. P. S. Shellard; A. Stebbins; S. Veeraraghavan

1994-01-01

158

Pressure- and temperature-induced transformations in crystalline polymers of C{sub 60}  

SciTech Connect

The great advantage of the C{sub 60} molecule is its potential for polymerization, due to which the molecule can be the building block of new all carbon materials. In addition, it contains, both sp{sup 2} and sp{sup 3} hybridized carbon atoms, which allows synthesizing new carbon materials with desired physicochemical properties using both types of carbon bonding. The one- and two-dimensional polymeric phases of C{sub 60} are prototype materials of this sort. Their properties, especially polymerization under pressure and room temperature via covalent bonding between molecules belonging to adjacent polymeric chains or polymeric layers, can be used for further development of new materials. The present review focuses on the study of the pressure-induced polymerization and thermodynamic stability of these materials and their recovered new phases by in-situ high-pressure Raman and X-ray diffraction studies. The phonon spectra show that the fullerene molecular cage in the high-pressure phases is preserved, while these polymers decompose under heat treatment into the initial fullerene C{sub 60} monomer.

Meletov, K. P., E-mail: mele@issp.ac.ru [Russian Academy of Sciences, Institute of Solid State Physics (Russian Federation); Kourouklis, G. A. [Aristotle University of Thessaloniki GR-54006, Physics Division, School of Technology (Greece)

2012-10-15

159

Influence of elastic properties on the strain induced by ion irradiation in crystalline materials  

NASA Astrophysics Data System (ADS)

Cubic zirconia, an elastically anisotropic material, has been irradiated with 300 keV Cs+ ions and the irradiation-induced elastic strain has been measured using x-ray diffraction (XRD). In order to highlight the influence of the elastic properties on the strain level, two different cases have been investigated: (i) {1?0?0} versus {1?1?1}-oriented zirconia single crystals and (ii) {1?0?0} zirconia versus {1?0?0} strontium titanate. In the former case, raw experimental results show that the {1?0?0} planes deform less than the {1?1?1} planes. However, with a modelling that takes into account the effect of the elastic properties, it is demonstrated that the strain due to irradiation defects only is the same for both orientations (with a maximum value of ˜0.8%). Combined use of this modelling and of a dedicated computer program for fitting XRD data allowed determining both defect concentration (˜1%) and relaxation volume (˜0.5 atomic volume). In the latter case, it is shown that elastic properties affect the measured strain in irradiated zirconia and strontium titanate. However, a difference between the two materials remains even taking into account this effect, confirming that different compounds of a same class of materials (namely ceramic oxides) can exhibit a different response to ion irradiation.

Debelle, A.; Boulle, A.; Rakotovao, F.; Moeyaert, J.; Bachelet, C.; Garrido, F.; Thomé, L.

2013-01-01

160

Radiation-induced bystander signalling in cancer therapy  

PubMed Central

Our understanding of how radiation kills normal and tumour cells has been based on an intimate knowledge of the direct induction of DNA damage and its cellular consequences. What has become clear is that, as well as responses to direct DNA damage, cell–cell signalling — known as the bystander effect — mediated through gap junctions and inflammatory responses may have an important role in the response of cells and tissues to radiation exposure and also chemotherapy agents. This Review outlines the key aspects of radiation-induced intercellular signalling and assesses its relevance for existing and future radiation-based therapies.

Prise, Kevin M.; O'Sullivan, Joe M.

2010-01-01

161

Radiation-induced malignant and atypical peripheral nerve sheath tumors  

SciTech Connect

The reported peripheral nerve complications of therapeutic irradiation in humans include brachial and lumbar plexus fibrosis and cranial and peripheral nerve atrophy. We have encountered 9 patients with malignant (7) and atypical (2) peripheral nerve tumors occurring in an irradiated site suggesting that such tumors represent another delayed effect of radiation treatment on peripheral nerve. In all instances the radio-theray was within an acceptable radiation dosage, yet 3 patients developed local radiation-induced skin and bony abnormalities. The malignant peripheral nerve sheath tumors developed only in the radiation port. Animal studies support the clinical observation that malignant peripheral nerve sheath tumors can occur as a delayed effect of irradiation.

Foley, K.M.; Woodruff, J.M.; Ellis, F.T.; Posner, J.B.

1980-04-01

162

Radiation-induced apoptosis in microvascular endothelial cells.  

PubMed Central

The response of the microvasculature to ionizing radiation is thought to be an important factor in the overall response of both normal tissues and tumours. It has recently been reported that basic fibroblast growth factor (bFGF), a potent mitogen for endothelial cells, protects large vessel endothelial cells from radiation-induced apoptosis in vitro. Microvessel cells are phenotypically distinct from large vessel cells. We studied the apoptotic response of confluent monolayers of capillary endothelial cells (ECs) to ionizing radiation and bFGF. Apoptosis was assessed by identifying changes in nuclear morphology, recording cell detachment rates and by detecting internucleosomal DNA fragmentation. Withdrawal of bFGF alone induces apoptosis in these monolayers. The magnitude of this apoptotic response depends upon the duration of bFGF withdrawal. Irradiation (2-10 Gy) induces apoptosis in a dose-dependent manner. Radiation-induced apoptosis occurs in a discrete wave 6-10 h after irradiation, and radiation-induced apoptosis is enhanced in cultures that are simultaneously deprived of bFGF. For example, 6 h after 10 Gy, 44.3% (s.e. 6.3%) of cells in the monolayer simultaneously deprived of bFGF exhibit apoptotic morphology compared with 19.8% (s.e. 3.8%) in the presence of bFGF. These studies show that either bFGF withdrawal or ionizing radiation can induce apoptosis in confluent monolayers of capillary endothelial cells and that radiation-induced apoptosis can be modified by the presence of bFGF. Images Figure 1 Figure 2 Figure 4 Figure 5

Langley, R. E.; Bump, E. A.; Quartuccio, S. G.; Medeiros, D.; Braunhut, S. J.

1997-01-01

163

Thermodynamic processes induced by coherent radiation  

NASA Technical Reports Server (NTRS)

It is shown by quantum statistics that under certain stated conditions the entropy of coherent radiation is zero and it is still negligible for multimode laser operation. This makes possible gas kinetic processes which, to a small extent, have already been observed or even utilized, but which can be greatly enhanced by an optimized choice of molecular structures and radiation conditions. Radiative cooling of gases is discussed in detail. The conditions for maximum heat withdrawal are derived, and it is proposed that the processes of cooling and relaxation heating can be sufficiently separated in time to achieve certain effects and thermodynamic cycles. One of these is the complete conversion, possible in principle, of coherent radiation into work. This concept is based on a heat pump process followed by heat-to-work conversion, the heat rejected being just equal to that withdrawn by radiation. The conditions for complete conversion turn out to be the same as for maximum heat withdrawal. The feasibility of these processes depends on the degree to which practical conditions can be met, and on the validity of certain assumptions which have to await experimental verification.

Garbuny, M.

1977-01-01

164

Radiation induces aerobic glycolysis through reactive oxygen species  

PubMed Central

Background and purpose Although radiation induced reoxygenation has been thought to increase radiosensitivity, we have shown that its associated oxidative stress can have radioprotective effects, including stabilization of the transcription factor hypoxia inducible factor 1 (HIF-1). HIF-1 is known to regulate many of the glycolytic enzymes, thereby promoting aerobic glycolysis, which is known to promote treatment resistance. Thus, we hypothesized that reoxygenation after radiation would increase glycolysis. We previously showed that blockade of oxidative stress using a superoxide dismutase (SOD) mimic during reoxygenation can downregulate HIF-1 activity. Here we tested whether concurrent use of this drug with radiotherapy would reduce the switch to a glycolytic phenotype. Materials and methods 40 mice with skin fold window chambers implanted with 4T1 mammary carcinomas were randomized into (1) no treatment, (2) radiation alone, (3) SOD mimic alone, and (4) SOD mimic with concurrent radiation. All mice were imaged on the ninth day following tumor implantation (30 h following radiation treatment) following injection of a fluorescent glucose analog, 2-[N-(7-nitrobenz-2-oxa-1,3-diaxol-4-yl)amino]-2-deoxyglucose (2-NBDG). Hemoglobin saturation was measured by using hyperspectral imaging to quantify oxygenation state. Results Mice treated with radiation showed significantly higher 2-NBDG fluorescence compared to controls (p = 0.007). Hemoglobin saturation analysis demonstrated reoxygenation following radiation, coinciding with the observed increase in glycolysis. The concurrent use of the SOD mimic with radiation demonstrated a significant reduction in 2-NBDG fluorescence compared to effects seen after radiation alone, while having no effect on reoxygenation. Conclusions Radiation induces an increase in tumor glucose demand approximately 30 h following therapy during reoxygenation. The use of an SOD mimic can prevent the increase in aerobic glycolysis when used concurrently with radiation, without preventing reoxygenation.

Zhong, Jim; Rajaram, Narasimhan; Brizel, David M.; Frees, Amy E.; Ramanujam, Nirmala; Batinic-Haberle, Ines; Dewhirst, Mark W.

2013-01-01

165

Radiation-induced changes in carboxymethylated chitosan  

NASA Astrophysics Data System (ADS)

This study focuses on the radiation effect of ?-ray on carboxymethylated chitosan (CM-chitosan) in solid state. The changes in molecular weight of CM-chitosan with absorbed dose were monitored by viscosity method. Experimental results indicated that random chain scissions took place under irradiation. Radiation chemical yield ( Gd) of CM-chitosan in solid state with N 2-saturated was 0.49, which showed CM-chitosan has high radiation stability. Biomaterials composed of CM-chitosan can be thought to sterilize with low absorbed dose. FTIR and UV spectra showed that main chain structures of CM-chitosan were retained, carbonyl/carboxyl groups were formed and partial amino groups were eliminated in high absorbed dose. XRD patterns identified that the degradation of CM-chitosan occurred mostly in amorphous region.

Huang, Ling; Peng, Jing; Zhai, Maolin; Li, Jiuqiang; Wei, Genshuan

2007-11-01

166

Self-nucleation free and dimension dependent metal-induced lateral crystallization of amorphous germanium for single crystalline germanium growth on insulating substrate  

NASA Astrophysics Data System (ADS)

In this work we have investigated Ni- or Au-induced crystallization and the lateral crystallization of planar amorphous germanium (?-Ge) on silicon dioxide at 360 °C without the deleterious effects of thermally induced self-nucleation. Subsequently, single crystalline Ge growth has been achieved on SiO2 by making dimension of ?-Ge line to be smaller than the size of grains formed using Ni- and Au-induced lateral crystallizations at 360 °C. This method can be used to form the channel region of the MOS devices in upper layers of the three-dimensional integrated circuits at low temperatures.

Park, Jin-Hong; Tada, Munehiro; Kapur, Pawan; Peng, Hailin; Saraswat, Krishna C.

2008-09-01

167

Radiation-induced cognitive impairment-from bench to bedside  

PubMed Central

Approximately 100 000 patients per year in the United States with primary and metastatic brain tumor survive long enough (>6 months) to develop radiation-induced brain injury. Before 1970, the human brain was thought to be radioresistant; the acute central nervous system (CNS) syndrome occurs after single doses of ?30 Gy, and white matter necrosis can occur at fractionated doses of ?60 Gy. Although white matter necrosis is uncommon with modern radiation therapy techniques, functional deficits, including progressive impairments in memory, attention, and executive function have become increasingly important, having profound effects on quality of life. Preclinical studies have provided valuable insights into the pathogenic mechanisms involved in radiation-induced cognitive impairment. Although reductions in hippocampal neurogenesis and hippocampal-dependent cognitive function have been observed in rodent models, it is important to recognize that other brain regions are affected; non–hippocampal-dependent reductions in cognitive function occur. Neuroinflammation is viewed as playing a major role in radiation-induced cognitive impairment. During the past 5 years, several preclinical studies have demonstrated that interventional therapies aimed at modulating neuroinflammation can prevent/ameliorate radiation-induced cognitive impairment independent of changes in neurogenesis. Translating these exciting preclinical findings to the clinic offers the promise of improving the quality of life in patients with brain tumors who receive radiation therapy.

Greene-Schloesser, Dana; Robbins, Mike E.

2012-01-01

168

Use of probiotics for prevention of radiation-induced diarrhea  

PubMed Central

AIM: To investigate the efficacy of a high-potency probiotic preparation on prevention of radiation-induced diarrhea in cancer patients. METHODS: This was a double-blind, placebo-controlled trial. Four hundred and ninety patients who underwent adjuvant postoperative radiation therapy after surgery for sigmoid, rectal, or cervical cancer were assigned to either the high-potency probiotic preparation VSL#3 (one sachet t.i.d.,) or placebo starting from the first day of radiation therapy. Efficacy endpoints were incidence and severity of radiation-induced diarrhea, daily number of bowel movements, and the time from the start of the study to the use of loperamide as rescue medication. RESULTS: More placebo patients had radiation-induced diarrhea than VSL#3 patients (124 of 239 patients, 51.8%, and 77 of 243 patients, 31.6%; P < 0.001) and more patients given placebo suffered grade 3 or 4 diarrhea compared with VSL#3 recipients (55.4% and 1.4%, P < 0.001). Daily bowel movements were 14.7 ± 6 and 5.1 ± 3 among placebo and VSL#3 recipients (P < 0.05), and the mean time to the use of loperamide was 86 ± 6 h for placebo patients and 122 ± 8 h for VSL#3 patients (P < 0.001). CONCLUSION: Probiotic lactic acid-producing bacteria are an easy, safe, and feasible approach to protect cancer patients against the risk of radiation-induced diarrhea.

Delia, P; Sansotta, G; Donato, V; Frosina, P; Messina, G; De Renzis, C; Famularo, G

2007-01-01

169

Radiation-induced changes in permeability in unilamellar phospholipid liposomes.  

PubMed

Gamma-radiation-induced oxidative damage in unilamellar dipalmitoylphosphatidylcholine liposomes was investigated using a fluorescence technique. Liposomal changes in permeability induced by gamma radiation were monitored by measuring the leakage of pre-encapsulated 6-carboxyfluorescein, and alterations in lipid bilayer fluidity were determined by 1,6-diphenyl-1,3,5-hexatriene fluorescence polarization. The changes in permeability and fluidity in the bilayer were found to be dependent on the radiation dose in a biphasic fashion. The results are interpreted in terms of lipid bilayer fluidization after exposure to doses up to 1 kGy, but rigidization of the bilayer at higher doses. These results indicate a relationship between alterations in permeability and fluidity in the lipid bilayer after irradiation. The vesicles were protected significantly against radiation-induced oxidative damage in the presence of alpha-tocopherol and ascorbic acid. Radiation-induced changes in the permeability of the liposomes after exposure to gamma radiation and their modification by antioxidants indicate the involvement of a free radical mechanism in the production of damage, which may offer new insights in to the modification of cellular radiosensitivity by modulation of membrane damage. PMID:12005548

Marathe, Dipti; Mishra, K P

2002-06-01

170

Radiation-induced biomarkers for the detection and assessment of absorbed radiation doses  

PubMed Central

Radiation incident involving living organisms is an uncommon but a very serious situation. The first step in medical management including triage is high-throughput assessment of the radiation dose received. Radiation exposure levels can be assessed from viability of cells, cellular organelles such as chromosome and different intermediate metabolites. Oxidative damages by ionizing radiation result in carcinogenesis, lowering of the immune response and, ultimately, damage to the hematopoietic system, gastrointestinal system and central nervous system. Biodosimetry is based on the measurement of the radiation-induced changes, which can correlate them with the absorbed dose. Radiation biomarkers such as chromosome aberration are most widely used. Serum enzymes such as serum amylase and diamine oxidase are the most promising biodosimeters. The level of gene expression and protein are also good biomarkers of radiation.

Rana, Sudha; Kumar, Raj; Sultana, Sarwat; Sharma, Rakesh Kumar

2010-01-01

171

Mechanisms of Radiation-Induced Bone Loss and Effects on Prostate Cancer Bone Metastases.  

National Technical Information Service (NTIS)

Patients with prostate cancer frequently receive radiation therapy. Although radiation therapy is effective for the treatment of primary tumors, bystander bone absorbs approximately half of the radiation dose and thus may cause adverse radiation-induced e...

L. E. Wright

2013-01-01

172

Role of PPARs in Radiation-Induced Brain Injury  

PubMed Central

Whole-brain irradiation (WBI) represents the primary mode of treatment for brain metastases; about 200 000 patients receive WBI each year in the USA. Up to 50% of adult and 100% of pediatric brain cancer patients who survive >6 months post-WBI will suffer from a progressive, cognitive impairment. At present, there are no proven long-term treatments or preventive strategies for this significant radiation-induced late effect. Recent studies suggest that the pathogenesis of radiation-induced brain injury involves WBI-mediated increases in oxidative stress and/or inflammatory responses in the brain. Therefore, anti-inflammatory strategies can be employed to modulate radiation-induced brain injury. Peroxisomal proliferator-activated receptors (PPARs) are ligand-activated transcription factors that belong to the steroid/thyroid hormone nuclear receptor superfamily. Although traditionally known to play a role in metabolism, increasing evidence suggests a role for PPARs in regulating the response to inflammation and oxidative injury. PPAR agonists have been shown to cross the blood-brain barrier and confer neuroprotection in animal models of CNS disorders such as stroke, multiple sclerosis and Parkinson's disease. However, the role of PPARs in radiation-induced brain injury is unclear. In this manuscript, we review the current knowledge and the emerging insights about the role of PPARs in modulating radiation-induced brain injury.

Ramanan, Sriram; Zhao, Weiling; Riddle, David R.; Robbins, Mike E.

2010-01-01

173

Pathogenesis of Radiation-Induced Osteosarcomas.  

National Technical Information Service (NTIS)

Results backed by experiments are presented here for the osteosarcoma induction in mice after incorporation of radium-224 or thorium-227. The dose-response relationship for osteosarcoma induction by short-lived alpha radiation is very much influenced by t...

A. Luz

1980-01-01

174

Neutron Radiation Induced Degradation of Diode Characteristics.  

National Technical Information Service (NTIS)

Neutron radiation effects on diode current-voltage characteristics have been studied for a variety of diode over 1x10 to the 13th to 3x10 to the 15th n/sq. cm 1 MeV equivalent neutron fluence range. A classification scheme consisting of three types of neu...

S. M. Khanna G. T. Pepper R. E. Stone

1992-01-01

175

Radiation pressure induced instability in Saturn's rings  

NASA Astrophysics Data System (ADS)

A mechanism for producing density dependent diffusive instability as a result of radiation pressure in a planetary ring is proposed. This instability is operative for particles ?1 cm, and may explain the initial formation of the fine radial structure in Saturn's B-ring.

Clarke, T. L.

176

Radiation induced synthesis of molecularly imprinted polymers  

Microsoft Academic Search

A new synthetic procedure for preparation of molecularly imprinted polymers (MIPs) was developed. The polymerization process was initiated by ?-radiation, in the model system with (±)-menthol as a template molecule. The thermal stability of MIP was investigated by thermogravimetric analysis and differential scanning calorimetry, while the specific surface area was determined from Brumauer-Emmett-Teller isotherm. Adsorption properties and recognition capabilities of

Smiljana S. Milojkovi?; Dušan Kostoski; Jovan M. Nedeljkovi?

1997-01-01

177

Cellular Canceration Induced by Mobile Phone Radiation  

Microsoft Academic Search

With the rapid development of communication technology, there is a widespread use of mobile telephone, whose effect on human has been getting more and more attention. The electromagnetic wave can penetrate biosystems and interacts with biological tissue at different biological levels. Although many researchers have been studying biological effects of electromagnetic radiation for years, their results are not consistent and

Yang Lei; Wang MingLian; Hao DongMei; Zeng Yi

2010-01-01

178

Radiation-induced cerebellar chondrosarcoma. Case report  

SciTech Connect

The authors report a case of chondrosarcoma arising in the cerebellum 16 years after treatment of a cerebellar malignant astrocytoma by subtotal resection and irradiation. It is thought that the chondrosarcoma arising within the intracranial cavity was a probable consequence of previous ionizing radiation.

Bernstein, M.; Perrin, R.G.; Platts, M.E.; Simpson, W.J.

1984-07-01

179

Characterization of radiation-induced emesis in the ferret  

SciTech Connect

Forty-eight ferrets (Mustela putorius furo) were individually head-shielded and radiated with bilateral cobalt 60 gamma radiation at 100 cGy min at doses ranging between 49 and 601 cGy. The emetic threshold was observed at 69 cGy, the ED 50 was calculated as 77 cGy, and 100% incidence of emesis occurred at 201 cGy. With increasing doses of radiation, the latency to first emesis after radiation decreased dramatically, whereas the duration of the prodromal period increased. Two other sets of experiments suggest that dopaminergic mechanisms play a minor role in radiation-induced emesis in the ferret. Twenty-two animals were injected either intravenously or subcutaneously with 30 to 300 micrograms /kg of apomorphine. Fewer than 50% of the animals vomited to 300 micrograms/kg apomorphine; central dopaminergic receptor activation was apparent at all doses. Another eight animals received 1 mg/kg domperidone prior to either 201 (n=4) or 401 (n=4) cGy radiation and their emetic responses were compared with NaCi-injected-irradiated controls (n=8). At 201 cGy, domperidone significantly reduced only the total time in emetic behavior. At 401 cGy, domperidone had no salutary effect on radiation-induced emesis. The emetic responses of the ferret to radiation and apomorphine are compared with these responses in other vomiting species.

King, G.L.

1988-01-01

180

Characterization of radiation-induced emesis in the ferret  

SciTech Connect

Forty-eight ferrets (Mustela putorius furo) were individually head-shielded and radiated with bilateral /sup 60/Co gamma radiation at 100 cGy min-1 at doses ranging between 49 and 601 cGy. The emetic threshold was observed at 69 cGy, the ED50 was calculated at 77 cGy, and 100% incidence of emesis occurred at 201 cGy. With increasing doses of radiation, the latency to first emesis after radiation decreased dramatically, whereas the duration of the prodromal period increased. Two other sets of experiments suggest that dopaminergic mechanisms play a minor role in radiation-induced emesis in the ferret. Twenty-two animals were injected either intravenously or subcutaneously with 30 to 300 micrograms/kg of apomorphine. Fewer than 50% of the animals vomited to 300 micrograms/kg apomorphine; central dopaminergic receptor activation was apparent at all doses. Another eight animals received 1 mg/kg domperidone prior to either 201 (n = 4) or 401 (n = 4) cGy radiation and their emetic responses were compared with NaCl-injected-irradiated controls (n = 8). At 201 cGy, domperidone significantly reduced only the total time in emetic behavior. At 401 cGy, domperidone had no salutary effect on radiation-induced emesis. The emetic responses of the ferret to radiation and apomorphine are compared with these responses in other vomiting species.

King, G.L.

1988-06-01

181

Simple method to demonstrate radiation-inducible radiation resistance in microbial cells.  

PubMed Central

A simple method for detection of radiation-inducible radiation resistance was developed by irradiating aliquots (0.01 ml) of cell suspension on agar plates. Part of each experimental plate was subjected to an induction treatment, and subsequent radiation resistance was compared with that of untreated cells on the same plate. The UV radiation resistance of a Micrococcus sp. was increased approximately 1.6 times by an induction treatment. This simple procedure of irradiating cells in a "fixed" position on agar avoided washing, centrifugation, and cell enumeration required in traditional methods. Images

Tan, S T; Maxcy, R B

1986-01-01

182

Simple method to demonstrate radiation-inducible radiation resistance in microbial cells  

SciTech Connect

A simple method for detection of radiation-inducible radiation resistance was developed by irradiating aliquots (0.01 ml) of cell suspension on agar plates. Part of each experimental plate was subjected to an induction treatment, and subsequent radiation resistance was compared with that of untreated cells on the same plate. The UV radiation resistance of a Micrococcus sp. was increased approximately 1.6 times by an induction treatment. This simple procedure of irradiating cells in a fixed position on agar avoided washing, centrifugation, and cell enumeration required in traditional methods.

Tan, S.T.; Maxcy, R.B.

1986-01-01

183

Solution combustion synthesis and visible light-induced photocatalytic activity of mixed amorphous and crystalline MgAl 2O 4 nanopowders  

Microsoft Academic Search

Mixed amorphous and crystalline MgAl2O4 nanopowders with visible light-induced photocatalytic activity were prepared via a simple solution combustion method using glycine and urea as fuel mixtures. The obtained samples were characterized by X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray, transmission electron microscopy, Brunauer–Emmett–Teller (BET) surface area, thermogravimetry, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and UV–Vis diffuse reflection

Fa-tang Li; Ye Zhao; Ying Liu; Ying-juan Hao; Rui-hong Liu; Di-shun Zhao

2011-01-01

184

Radiation induced growth of micro crystallites  

SciTech Connect

Generation of colloidal particles during the radiolysis of aqueous solutions was already observed in the early days of radiation chemistry. Systematic studies using radiation chemistry techniques as synthetic tools in the preparation of colloidal particles, primarily metallic particles, were begun approximately a decade ago in conjunction since they were found to catalyze multi-electron redox processes. A large number of metallic colloidal particles were then synthesized, including silver, gold, platinum, iridium, nickel, cadmium, and others. More recently, attention has turned to semiconductor colloidal particles. The stimulus to these studies is the observation of quantum size effects in small semiconductor particles that exhibit hybrid properties between those of the molecular species and the solid state bulk material. In the following we discuss our own observations on the evolution of semiconductor particles whose growth has been initiated by pulse radiolysis. 13 refs., 2 figs.

Meisel, D.

1991-01-01

185

Mitigation of radiation induced surface contamination  

DOEpatents

A process for mitigating or eliminating contamination and/or degradation of surfaces having common, adventitious atmospheric contaminants adsorbed thereon and exposed to radiation. A gas or a mixture of gases is introduced into the environment of a surface(s) to be protected. The choice of the gaseous species to be introduced (typically a hydrocarbon gas, water vapor, or oxygen or mixtures thereof) is dependent upon the contaminant as well as the ability of the gaseous species to bind to the surface to be protected. When the surface and associated bound species are exposed to radiation reactive species are formed that react with surface contaminants such as carbon or oxide films to form volatile products (e.g., CO, CO.sub.2) which desorb from the surface.

Klebanoff, Leonard E. (Dublin, CA) [Dublin, CA; Stulen, Richard H. (Livermore, CA) [Livermore, CA

2003-01-01

186

Chemotherapy or radiation-induced oral mucositis.  

PubMed

Oral mucositis is a significant toxicity of systemic chemotherapy and of radiation therapy to the head and neck region. The morbidity of oral mucositis can include pain, nutritional compromise, impact on quality of life, alteration in cancer therapy, risk for infection, and economic costs. Management includes general symptomatic support and targeted therapeutic interventions for the prevention or treatment of oral mucositis. Evidence-based clinical practice guidelines are available to guide clinicians in the selection of effective management strategies. PMID:24655526

Lalla, Rajesh V; Saunders, Deborah P; Peterson, Douglas E

2014-04-01

187

Tristetraprolin Mediates Radiation-Induced TNF-? Production in Lung Macrophages  

PubMed Central

The efficacy of radiation therapy for lung cancer is limited by radiation-induced lung toxicity (RILT). Although tumor necrosis factor-alpha (TNF-?) signaling plays a critical role in RILT, the molecular regulators of radiation-induced TNF-? production remain unknown. We investigated the role of a major TNF-? regulator, Tristetraprolin (TTP), in radiation-induced TNF-? production by macrophages. For in vitro studies we irradiated (4 Gy) either a mouse lung macrophage cell line, MH-S or macrophages isolated from TTP knockout mice, and studied the effects of radiation on TTP and TNF-? levels. To study the in vivo relevance, mouse lungs were irradiated with a single dose (15 Gy) and assessed at varying times for TTP alterations. Irradiation of MH-S cells caused TTP to undergo an inhibitory phosphorylation at Ser-178 and proteasome-mediated degradation, which resulted in increased TNF-? mRNA stabilization and secretion. Similarly, MH-S cells treated with TTP siRNA or macrophages isolated from ttp (?/?) mice had higher basal levels of TNF-?, which was increased minimally after irradiation. Conversely, cells overexpressing TTP mutants defective in undergoing phosphorylation released significantly lower levels of TNF-?. Inhibition of p38, a known kinase for TTP, by either siRNA or a small molecule inhibitor abrogated radiation-induced TNF-? release by MH-S cells. Lung irradiation induced TTPSer178 phosphorylation and protein degradation and a simultaneous increase in TNF-? production in C57BL/6 mice starting 24 h post-radiation. In conclusion, irradiation of lung macrophages causes TTP inactivation via p38-mediated phosphorylation and proteasome-mediated degradation, leading to TNF-? production. These findings suggest that agents capable of blocking TTP phosphorylation or stabilizing TTP after irradiation could decrease RILT.

Ray, Dipankar; Shukla, Shirish; Allam, Uday Sankar; Helman, Abigail; Ramanand, Susmita Gurjar; Tran, Linda; Bassetti, Michael; Krishnamurthy, Pranathi Meda; Rumschlag, Matthew; Paulsen, Michelle; Sun, Lei; Shanley, Thomas P.; Ljungman, Mats; Nyati, Mukesh K.; Zhang, Ming; Lawrence, Theodore S.

2013-01-01

188

Monitoring of radiation-induced germline mutation in humans.  

PubMed

Estimating the genetic hazards of radiation and other mutagens in humans depends on extrapolation from experimental systems. Recent data have shown that minisatellite loci provide a useful and sensitive experimental approach for monitoring radiation-induced mutation in humans. This review describes the progress made in validating this approach and presents the results of recent publications on the analysis of minisatellite mutation rates in the irradiated families. PMID:14652802

Dubrova, Yuri E

2003-09-01

189

Radiation-induced outgassing from Type 304 stainless steel  

Microsoft Academic Search

A Type 304 stainless-steel vacuum system has been designed and constructed to study radiation-induced outgassing when this material is exposed to ⁶°Co gamma radiation. An analytical model has been developed that predicts the outgassing from Type 304 stainless steel to be 5 x 10⁻¹° Pa.l\\/cm².s per Mrad\\/h. Experiments determined the value for Type 304 stainless steel after bakeout at 300°C

T. P. Toepker; J. N. Anno

1979-01-01

190

Radiation-induced bystander effects, carcinogenesis and models  

Microsoft Academic Search

Implications for carcinogenesis of radiation-induced bystander effects are both mechanistic and practical. They include induction of second cancers, perturbations to tissue social control and induction of genomic instability and delayed or immediate mutations in areas not receiving a direct deposition of energy. Bystander effects have consequences for DNA damage-mutation-cancer initiation paradigms of radiation carcinogenesis that provide the mechanistic justification for

Carmel Mothersill; Colin Seymour

2003-01-01

191

Radiation-Induced Bystander Effects in Cultured Human Stem Cells  

Microsoft Academic Search

BackgroundThe radiation-induced “bystander effect” (RIBE) was shown to occur in a number of experimental systems both in vitro and in vivo as a result of exposure to ionizing radiation (IR). RIBE manifests itself by intercellular communication from irradiated cells to non-irradiated cells which may cause DNA damage and eventual death in these bystander cells. It is known that human stem

Mykyta V. Sokolov; Ronald D. Neumann; Henning Ulrich

2010-01-01

192

NF-?B signaling modulates radiation?induced microglial activation.  

PubMed

Microglial activation has been suggested to be associated with the incidence of radiation-induced brain injury. The present study investigated the molecular mechanism(s) involved in radiation-induced activation of the microglia. Mouse microglial BV-2 cells were exposed to different doses of radiation. The release of inflammatory factors was evaluated by enzyme-linked immunosorbent assay and real-time reverse transcriptase polymerase chain reaction. Protein expression was determined by immunocytochemistry and immunoblotting. Microglial activation was induced by radiation [>16 Gray (Gy)]. Activated cells exhibited a stouter spherical morphology and the levels of ionized calcium-binding adapter molecule-1 and CD68 were considerably upregulated. The generation of inflammatory factors, including interleukin-1? (IL-1?), tumor necrosis factor-? (TNF-?), IL-6, toll?like receptor 8 (TLR-8) and cyclooxygenase 2 (COX-2), was increased and peaked at either 3 or 6 h after radiation treatment. Phosphorylated ?-histone 2A, member X (?-H2AX), which facilitates DNA double-strand breaks (DSBs), was upregulated at 3 h post-radiation treatment. This was accompanied by the nuclear translocation of the nuclear factor-?B (NF-?B) p65 subunit. Moreover, 3 h following radiation treatment, the NF-?B essential modulator (NEMO) was markedly elevated, whereas the NF-?B regulatory inhibitor-? (I?B-?) was considerably decreased. Our results demonstrate that the NF-?B signaling pathway may trigger microglial activation and release of inflammatory factors following irradiation. These findings may provide valuable insight into understanding the molecular mechanism(s) involved in brain injury induced by radiation therapy. PMID:24756575

Xue, Jun; Dong, Ji-Hua; Huang, Guo-Dong; Qu, Xiao-Fei; Wu, Gang; Dong, Xiao-Rong

2014-06-01

193

Simvastatin attenuates radiation-induced tissue damage in mice.  

PubMed

The aim of this study was to investigate the protective effect of simvastatin against radiation-induced tissue injury in mice. Mice were radiated with 4 Gy or 8 Gy after 20 mg/kg/d simvastatin treatment over 2 weeks. Morphological changes were observed in the jejunum and bone marrow, and apoptotic cells were determined in both tissues. Peripheral blood cells were counted, and the superoxide dismutase (SOD) activity and the malondialdehyde (MDA) level in tissues of both thymus and spleen were measured. Compared with the radiation-only group, 20 mg/kg/d simvastatin administration significantly increased the mean villi height and decreased apoptotic cells in jejunum tissue, and stimulated regeneration and reduced apoptotic cells in bone marrow. Peripheral blood cell analysis revealed that simvastatin treatment induced a larger number of red blood cells and increased the hemoglobin level present after 4 Gy of radiation. Interestingly, it was also found that the number of peripheral endothelial progenitor cells was markedly increased following simvastatin administration. Antioxidant determination for tissues displayed that simvastatin therapy increased the SOD activity after both 4 and 8 Gy of radiation, but only decreased the MDA level after 4 Gy. Simvastatin ameliorated radiation-induced tissue damage in mice. The radioprotective effect of simvastatin was possibly related to inhibition of apoptosis and improvement of oxygen-carrying and antioxidant activities. PMID:24105712

Zhao, Xinbin; Yang, Hong; Jiang, Guojun; Ni, Min; Deng, Yaping; Cai, Jian; Li, Zhangpeng; Shen, Fuming; Tao, Xia

2014-03-01

194

Radiation-induced nonlinear optical response of quartz fibers  

NASA Astrophysics Data System (ADS)

The intensity of radiation-induced luminescence and transient optical losses in KU-1 (Russia) and K-3 (Japan) quartz glass optical tibers irradiated in a fast pulsed fission reactor (a pulse duration of 80 ?s and a neutron flux up to 7 × 1016 cm 2 s 2) has been measured in the visible range. The intensity of the fast luminescence component nonlinearly depends on the neutron flux. The luminescence intensity and the transient optical losses depend on the probe light intensity. Suppression of radiation-induced luminescence is observed at wavelengths that are longer or shorter than the probe light wavelength. Light probing leads to an increase in transient optical losses and a more rapid recovery of transparency. A model of two photon fluxes is proposed to analyze the relationship of the effects of suppression of radiation-induced luminescence and the increase in optical losses upon light probing. The effect of suppression of radiation-induced luminescence can be used to control the optical properties of fibers in radiation fields.

Plaksin, O. A.

2006-10-01

195

Squamous cell carcinoma antigen suppresses radiation-induced cell death  

PubMed Central

Previous study has demonstrated that squamous cell carcinoma antigen (SCCA) 1 attenuates apoptosis induced by TNF?, NK cell or anticancer drug. In this study, we have examined the effect of SCCA2, which is highly homologous to SCCA1, but has different target specificity, against radiation-induced apoptosis, together with that of SCCA1. We demonstrated that cell death induced by radiation treatment was remarkably suppressed not only in SCCA1 cDNA-transfected cells, but also in SCCA2 cDNA-transfected cells. In these transfectants, caspase 3 activity and the expression of activated caspase 9 after radiation treatment were suppressed. Furthermore, the expression level of phosphorylated p38 mitogen-activated protein kinase (p38 MAPK) was suppressed compared to that of the control cells. The expression level of upstream stimulator of p38 MAPK, phosphorylated MKK3/MKK6, was also suppressed in the radiation-treated cells. Thus, both SCCA1 and SCCA2 may contribute to survival of the squamous cells from radiation-induced apoptosis by regulating p38 MAPK pathway. © 2001 Cancer Research Campaign http://www.bjcancer.com

Murakami, A; Suminami, Y; Hirakawa, H; Nawata, S; Numa, F; Kato, H

2001-01-01

196

Modulation of Radiation-Induced Apoptosis by Thiolamines  

NASA Technical Reports Server (NTRS)

Exposure to the thiolamine radioprotector N-(2-mercaptoethyl)-1,3-propanediamine (WR-1065) induced apoptosis in the mouse TB8-3 hybridoma after 60-minute (LD(sub50) = 4.5mM) or during a 20-hour (LD(sub50) = 0.15 mM) exposure. In contrast, a 20-hour exposure to 17 mM L-cysteine or 10 mM cysteamine was required to induce 50 percent apoptosis within 20 hours. Apoptosis was not induced by either a 60-minute or 20-hour exposure to 10 mM of the thiazolidime prodrugs ribose-cysteine (RibCys) or ribose-cysteamine (RibCyst). Thiolamine-induced apoptosis appeared to be a p53-independent process since it was induced by WR-1065 exposure in human HL60 cells. Exposure to WR-1065 (4mM for 15 minutes) or cysteine (10mM for 60 minutes) before and during irradiation protected cells against the induction of both DNA double-strand breaks and apoptosis, while exposure to RibCys (10 mM for 3 hours) did not. Treatment with either WR-1065, cysteine, RibCys or RibCyst for 60 minutes beginning 60 minutes after irradiation did not affect the level of radiation-induced apoptosis. In contrast, treatment with either cysteine, cysteamine or RibCys for 20 hours beginning 60 minutes after irradiation enhanced radiation-induced apoptosis. Similar experiments could not be conducted with WR-1065 because of its extreme toxicity. Our results indicate that thiolamine enhancement of radiation-induced apoptosis is not involved in their previously reported capacity to reduce radiation-induced mutations.

Warters, R. L.; Roberts, J. C.; Wilmore, B. H.; Kelley, L. L.

1997-01-01

197

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

NASA Astrophysics Data System (ADS)

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

Matsumoto, H.; Ohnishi, T.

198

Mechanisms of radiation-induced neoplastic cell transformation  

SciTech Connect

Studies with cultured mammalian cells demonstrated clearly that radiation can transform cells directly and can enhance the cell transformation by oncogenic DNA viruses. In general, high-LET heavy-ion radiation can be more effective than X and gamma rays in inducing neoplastic cell transformation. Various experimental results indicate that radiation-induced DNA damage, most likely double-strand breaks, is important for both the initiation of cell transformation and for the enhancement of viral transformation. Some of the transformation and enhancement lesions can be repaired properly in the cell, and the amount of irrepairable lesions produced by a given dose depends on the quality of radiation. An inhibition of repair processes with chemical agents can increase the transformation frequency of cells exposed to radiation and/or oncogenic viruses, suggesting that repair mechanisms may play an important role in the radiation transformation. The progression of radiation-transformed cells appears to be a long and complicated process that can be modulated by some nonmutagenic chemical agents, e.g., DMSO. Normal cells can inhibit the expression of transforming properties of tumorigenic cells through an as yet unknown mechanism. The progression and expression of transformation may involve some epigenetic changes in the irradiated cells. 38 references, 15 figures, 1 table.

Yang, T.C.H.; Tobias, C.A.

1984-04-01

199

Chemoprevention of Radiation Induced Rat Mammary Neoplasms  

NASA Technical Reports Server (NTRS)

Radiations encountered in space include protons and heavy ions such as iron as well as their secondaries. The relative biological effect (RBE) of these ions is not known, particularly at the doses and dose-rates expected for planetary missions. Neutrons, are not particularly relevant to space travel, but have been found experimentally to have an increase in their RBE with decreasing dose. If a similar trend of increasing RBE with decreasing dose is present for heavy ions and protons during irradiation in space, the small doses received during space travel could potentially have substantial carcinogenic risk. Clearly more investigation of the effects of heavy ions and protons is needed before accurate risk assessment for prolonged travel in space can be done. One means to mitigate the increased risk of cancer due to radiation exposure in space is by developing effective countermeasures that can reduce the incidence of tumor development. Tamoxifen has recently been shown to be an effective chemopreventive agent in both animal models and humans for the prevention of mammary tumors. Tamoxifen is a unique drug, with a highly specific mechanism of action affecting a specific radiation-sensitive population of epithelial cells in the mammary gland. In human studies, the annual incidence of a primary tumor in the contralateral breast of women with previous breast cancer is about 8 per 1000, making them an exceedingly high-risk group for the development of breast cancer. In this high risk group, treated with tamoxifen, daily, for 2 years, the incidence of a new primary tumor in the contralateral breast was approximately one third of that noted in the non-tamoxifen treatment group. Tamoxifen antagonizes the action of estrogen by competing for the nuclear receptor complex thereby altering the association of the receptor complex and nuclear binding sites. Its effects in reducing the development of breast cancer could be accomplished by controlling clinically undetectable microcancers, arresting preneoplastic lesions, or correcting abnormal environments which predispose to high risk of malignant transformation.

Huso, David L.

1999-01-01

200

INTERRELATIONS OF NUCLEIC ACID AND PROTEIN SYNTHESES IN RADIATION INDUCED MUTATION INDUCTION IN BACTERIA  

Microsoft Academic Search

During the past decade evidence has accumulated that an appreciable ; portion of radiation-induced mutations are due to chemical effects of radiation ; on sensitive metabolites. The shape of induced mutation frequency curves ; suggests that intracellular radiation-sensitive material is modified by radiation. ; This material is probably both limited in quantity and destroyed by radiat high ; doses of

F. L. Haas; C. O. Doudney

1958-01-01

201

Radiation-induced grain boundary segregation in nuclear reactor steels  

Microsoft Academic Search

The paper will review the various mechanisms of grain boundary segregation. These are: thermal equilibrium segregation (TES); neutron irradiation enhanced equilibrium segregation; thermal non-equilibrium segregation; and radiation-induced segregation (RIS). The neutron irradiation-induced mechanisms will be discussed in detail. Modelling of the neutron irradiation segregation effects will be outlined with reference to two approaches: non-equilibrium theory based models and rate theory

R. G. Faulkner

1997-01-01

202

Radiation induced leakage current in floating gate memory cells  

Microsoft Academic Search

Single ions impacting on SiO2 layers generate tracks of defects which may result in a Radiation Induced Leakage Current (RILC). This current is usually studied as the cumulative effect of ion-induced defects in capacitors with ultra-thin oxides. We are demonstrating and modeling this phenomenon in 10 nm oxides by using Floating Gate memories. The impact of a single, high-LET ion

G. Cellere; L. Larcher; A. Paccagnella; A. Visconti; M. Bonanomi

2005-01-01

203

Theory of Radiation-Induced Attenuation in Optical Fibers  

NASA Technical Reports Server (NTRS)

A new mathematical model for describing radiation-induced attenuation in optical fibers ispresented. Unlike the existing empirical power law, the new expression is dose- rate dependent andcan be used to predict low-dose-rate induced fiber loss occurring in space from the normally high-dose-rate results obtained in a ground-based laboratory. The new theory is in good agreement withthe experiment.

Liu, Duncan T. H.; Johnston, Alan R.

1993-01-01

204

Interleukin-32 Positively Regulates Radiation-Induced Vascular Inflammation  

SciTech Connect

Purpose: To study the role of interleukin-32 (IL-32), a novel protein only detected in human tissues, in ionizing radiation (IR)-induced vascular inflammation. Methods and Materials: Irradiated (0-6 Gy) human umbilical vein endothelial cells treated with or without various agents-a cytosolic phospholipase A2 (cPLA2) inhibitor, a cyclooxygenase-2 (Cox-2) inhibitor, or lysophosphatidylcholines (LPCs)-were used to assess IL-32 expression by Northern blot analysis and quantitative reverse transcriptase-polymerase chain reaction. Expression of cell adhesion molecules and leukocyte adhesion to endothelial cells using human acute monocytic leukemia cell line (THP-1) cells was also analyzed. Results: Ionizing radiation dramatically increased IL-32 expression in vascular endothelial cells through multiple pathways. Ionizing radiation induced IL-32 expression through nuclear factor {kappa}B activation, through induction of cPLA2 and LPC, as well as induction of Cox-2 and subsequent conversion of arachidonic acid to prostacyclin. Conversely, blocking nuclear factor {kappa}B, cPLA2, and Cox-2 activity impaired IR-induced IL-32 expression. Importantly, IL-32 significantly enhanced IR-induced expression of vascular cell adhesion molecules and leukocyte adhesion on endothelial cells. Conclusion: This study identifies IL-32 as a positive regulator in IR-induced vascular inflammation, and neutralization of IL-32 may be beneficial in protecting from IR-induced inflammation.

Kobayashi, Hanako; Yazlovitskaya, Eugenia M. [Department of Radiation Oncology, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN (United States); Lin, P. Charles [Department of Radiation Oncology, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN (United States); Department of Cancer Biology, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN (United States); Department of Cell and Development Biology, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN (United States)], E-mail: Charles.lin@vanderbilt.edu

2009-08-01

205

Neutrino mass induced radiatively by supersymmetric leptoquarks  

NASA Astrophysics Data System (ADS)

We show how nonzero Majorana neutrino masses can be radiatively generated by extending the MSSM with leptoquark chiral multiplets without violating R-parity. It is found that, with these particles, the R-parity conservation does not imply lepton number conservation. Neutrino masses generated at a one-loop level are closely related to the down quark mass matrix. The ratio of neutrino mass-squared splittings ?m2?2- ?1/?m2?3- ?2 obtained is naturally close to ?m2s-d/?m2b- s~10-3 which is in the right region required to explain both the atmospheric neutrino data and the MSW solutions for the solar neutrino data.

Chua, C.-K.; He, X.-G.; Hwang, W.-Y. P.

2000-04-01

206

Radiation-induced conductivity control in polyaniline blends/composites  

NASA Astrophysics Data System (ADS)

Polyaniline (PANI) blends with chlorine-containing polymers and copolymers and composites with HCl-releasing compounds were prepared to investigate their radiation response in terms of induced conductivities. Blends of non-conductive PANI with poly(vinyl chloride) (PVC), poly(vinylidene chloride- co-vinyl acetate), [P(VDC- co-VAc)], poly(vinylidene chloride- co-vinyl chloride), [P(VDC- co-VC)] were prepared in the form of as-cast films. A number of blends which are different in composition were exposed to gamma radiation and accelerated electrons to various doses, and the effects of irradiation type and composition of polymers on the conductivity of films were investigated by using conductivity measurements and UV-vis and FT-IR spectroscopy. The results clearly showed that ionizing radiation is an effective tool to induce and control conductivity in the blends of PANI-base with chlorine-carrying polymers as well as its composites prepared from HCl-releasing compounds such as chloral hydrate. The main mechanism behind this radiation-induced conductivity is in situ doping of PANI-base with HCl released from partner polymers and low molecular weight compounds by the effect of radiation.

Güven, Olgun

2007-08-01

207

Expansion of nanosized pores in low-crystallinity nanoparticle-assembled plates via a thermally induced increase in solid-state density.  

PubMed

We investigated thermally induced changes in a low-crystallinity hydroxyapatite (HAp)-nanoparticle-assembled plate containing nanosized pores. We first prepared an aqueous dispersion of low-crystallinity HAp nanoparticles (particle size, 48 nm) via a wet chemical process and then prepared the nanoparticle-assembled plate by drying the dispersion on an oil substrate to prevent crack formation. Before the plates were subjected to heat treatments, they contained 7.9-nm-sized pores because of the gap between the nanoparticles, and their porosity was 60%. After the heat treatments (600-1100 °C) were performed for 1 h, the solid-state density determined using helium pycnometry increased from 2.85 to 3.21 g/cm(3), and the pore size increased from 7.9 to 250 nm. These results indicate that the pore size expanded because of increases in crystallinity and density, despite the large decrease in the total volume because of thermally induced sintering of the nanoparticles. PMID:23777865

Okada, Masahiro; Fujiwara, Keiko; Uehira, Mayo; Matsumoto, Naoyuki; Takeda, Shoji

2013-09-01

208

Effect of solvents on radiation-induced ionic graft polymerization. [Gamma radiation  

SciTech Connect

The influence of various solvents on radiation-induced cationic (grafting of vinyl-n-butyl ether onto polyethylene) and anionic (grafting of 2-methyl-5-vinylpyridine onto polyethylene) graft polymerization was studied. This ionic grafting was performed in thoroughly dried systems at room temperature. It was established that electron-acceptor solvents promote cationic grafting but that electron-donor solvents promote the anionic. A clear correlation between the donor number of solvents and grafting value by the anionic mechanism was shown. There was no correlation between dielectric constants and grafting values. The reaction orders, according to monomer concentraton by 2-methyl-5-vinylpyridine grafting in various solvents, were equal to approximately 1.5 and 2 for the radical and anionic mechanisms, respectively. The effect of solvents on radiation-induced ionic graft polymerization is discussed. The results of this study indicate the correct choice of solvents for radiation-induced ionic grafting.

Kabanov, V.Ya.; Aliev, R.E.; Sidorova, L.P.

1980-03-01

209

Radiation-induced genomic instability and its implications for radiation carcinogenesis  

NASA Technical Reports Server (NTRS)

Radiation-induced genomic instability is characterized by an increased rate of genetic alterations including cytogenetic rearrangements, mutations, gene amplifications, transformation and cell death in the progeny of irradiated cells multiple generations after the initial insult. Chromosomal rearrangements are the best-characterized end point of radiation-induced genomic instability, and many of the rearrangements described are similar to those found in human cancers. Chromosome breakage syndromes are defined by chromosome instability, and individuals with these diseases are cancer prone. Consequently, chromosomal instability as a phenotype may underlie some fraction of those changes leading to cancer. Here we attempt to relate current knowledge regarding radiation-induced chromosome instability with the emerging molecular information on the chromosome breakage syndromes. The goal is to understand how genetic and epigenetic factors might influence the onset of chromosome instability and the role of chromosomal instability in carcinogenesis.

Huang, Lei; Snyder, Andrew R.; Morgan, William F.

2003-01-01

210

Blackbody-radiation-induced photodetachment of dipole-bound anions  

NASA Astrophysics Data System (ADS)

The lifetimes of dipole-bound anions due to photodetachment by thermal background blackbody radiation (BBR) are calculated using a simple analytic model. The calculated lifetimes are in reasonable agreement with those measured experimentally. It is shown that, at low temperatures, the temperature dependence of the ion lifetime is similar to that for BBR-induced photoionization of atoms.

Chernov, V. E.; Danilyan, A. V.; Dolgikh, A. V.; Dunning, F. B.; Zon, B. A.

2006-07-01

211

Radiation-induced segregation in alloy X-750  

SciTech Connect

Microstructural and microchemical evolution of an Alloy X-750 heat under neutron irradiation was studied in order to understand the origin of irradiation-assisted stress corrosion cracking. Both clustering of point defects and radiation-induced segregation at interfaces were observed. Although no significant changes in the precipitate structure were observed, boundaries exhibited additional depletion of Cr and Fe and enrichment of Ni.

Kenik, E.A.

1996-12-31

212

Radiation-induced segregation in alloy X-750  

Microsoft Academic Search

Microstructural and microchemical evolution of an Alloy X-750 heat under neutron irradiation was studied in order to understand the origin of irradiation-assisted stress corrosion cracking. Both clustering of point defects and radiation-induced segregation at interfaces were observed. Although no significant changes in the precipitate structure were observed, boundaries exhibited additional depletion of Cr and Fe and enrichment of Ni.

Kenik

1996-01-01

213

Radiation induced CNS toxicity – molecular and cellular mechanisms  

Microsoft Academic Search

Radiotherapy of tumours proximal to normal CNS structures is limited by the sensitivity of the normal tissue. Prior to the development of prophylactic strategies or treatment protocols a detailed understanding of the mechanisms of radiation induced CNS toxicity is mandatory. Histological analysis of irradiated CNS specimens defines possible target structures prior to a delineation of cellular and molecular mechanisms. Several

C Belka; W Budach; R D Kortmann; M Bamberg

2001-01-01

214

Genomic Instability Induced by Ionizing Radiation in Human Hepatocytes  

Microsoft Academic Search

The aim of this study was to characterize genomic instability induced by ionizing radiation (IR) in human hepatocytes as reflected by alterations in cloning efficiency, micronucleus (MN) frequency, and apoptosis. The human normal liver 7702 cell line (HL7702) was subjected to initial irradiation of Co-? ray at doses of 0 (control group), 2, 4, 6, 8, or 10 Gy in

Ya-Hui Zuo; Xu-Hong Dang; Hui-Fang Zhang; Jian-Gong Liu; Zhi-Kai Duan; Zhong-Wen Wang; Jian Tong

2012-01-01

215

Poor outcome in radiation-induced constrictive pericarditis  

SciTech Connect

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.

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

1993-01-15

216

Radiation-Induced Phosphorus Segregation in Austenitic and Ferritic Alloys.  

National Technical Information Service (NTIS)

The radiation induced surface segregation (RIS) of phosphorus in stainless steel attained a maximum at a dose of 0.8 dpa then decreased continually with dose. This decrease in the surface segregation of phosphorus at high dose levels has been attributed t...

J. L. Brimhall D. R. Baer R. H. Jones

1983-01-01

217

Effect of sodium meclofenamate on ultraviolet radiation induced carcinogenesis  

SciTech Connect

Sodium meclofenamate (Meclomen), an antiprostaglandin antileukotriene agent, was found in previous studies to protect primates against x-ray induced brain edema, esophagitis and cystitis. In the present study, it appeared to protect hairless mice against the carcinogenic effect of ultraviolet B-radiation.

Ambrus, J.L.; Ambrus, C.M.; Pickren, J.W.; Klein, E.

1984-01-01

218

SENSITIVITY TO RADIATION-INDUCED CANCER IN HEMOCHROMATOSIS  

EPA Science Inventory

Determination of dose-response relationships for radiation-induced cancer in segments of the population with high susceptibility is critical for understanding the risks of low dose and low dose rates to humans. Clean-up levels for radionuclides will depend upon the fraction of t...

219

Contribution to the Study of Radiation Induced Bone Tissue Cancer.  

National Technical Information Service (NTIS)

In this work four original observations of more or less long-delayed cancers induced by ionizing radiations are compared with 34 other cases in the literature, after which an attempt is made to establish a general and prognostic synthesis of the results; ...

M. Bouet

1975-01-01

220

Cosmology for grand unified theories with radiatively induced symmetry breaking  

Microsoft Academic Search

The treatment of first-order phase transitions for standard grand unified theories is shown to break down for models with radiatively induced spontaneous symmetry breaking. It is argued that proper analysis of these transitions which would take place in the early history of the universe can lead to an explanation of the cosmological homogeneity, flatness, and monopole puzzles.

Andreas Albrecht; P. J. Steinhardt

1982-01-01

221

Silicon radiation detector analysis using back electron beam induced current  

Microsoft Academic Search

A new technique for the observation and analysis of detects in silicon radiation detectors is described. This method uses an electron beam from a scanning electron microscope (SEM) impinging on the rear side of the p+n junction of the silicon detector, which itself is active and detects the electron beam induced current (EBIC). It is shown that this current is

R. Guye; P. Jarron

1987-01-01

222

Radiation-Induced Bystander Response: Mechanism and Clinical Implications  

PubMed Central

Significance: Absorption of energy from ionizing radiation (IR) to the genetic material in the cell gives rise to damage to DNA in a dose-dependent manner. There are two types of DNA damage; by a high dose (causing acute or deterministic effects) and by a low dose (related to chronic or stochastic effects), both of which induce different health effects. Among radiation effects, acute cutaneous radiation syndrome results from cell killing as a consequence of high-dose exposure. Recent advances: Recent advances in radiation biology and oncology have demonstrated that bystander effects, which are emerged in cells that have never been exposed, but neighboring irradiated cells, are also involved in radiation effects. Bystander effects are now recognized as an indispensable component of tissue response related to deleterious effects of IR. Critical issues: Evidence has indicated that nonapoptotic premature senescence is commonly observed in various tissues and organs. Senesced cells were found to secrete various proteins, including cytokines, chemokines, and growth factors, most of which are equivalent to those identified as bystander factors. Secreted factors could trigger cell proliferation, angiogenesis, cell migration, inflammatory response, etc., which provide a tissue microenvironment assisting tissue repair and remodeling. Future directions: Understandings of the mechanisms and physiological relevance of radiation-induced bystander effects are quite essential for the beneficial control of wound healing and care. Further studies should extend our knowledge of the mechanisms of bystander effects and mode of cell death in response to IR.

Suzuki, Keiji; Yamashita, Shunichi

2014-01-01

223

Radiation-induced transient darkening of optically transparent polymers  

SciTech Connect

Results are presented for the radiation-induced transient darkening of thin organic polymer films normally used as Cerenkov light emissions sources. The radiation source is a 27-MeV, 10-..mu..C, 200-ns electron beam generated by the PHERMEX accelerator. The typical dose for a single pulse is 5 Mrad. At this dose, the broadband time-resolved percent transmission above 520 nm was measured for four common polymers: polyimide (Kapton-H), polyethylene terephthalate (Mylar), cellulose acetate, and high-density polyethylene. Kapton was found to darken the most and polyethylene darkened the least. The recovery time to normal transmission for Kapton was found to be greater than 10--20 ..mu..s. The radiation-induced attenuation coefficient is shown to depend on electronic band energy separation. The results show that Kapton is not the material of choice for a Cerenkov light source.

Downey, S.W.; Builta, L.A.; Carlson, R.L.; Czuchlewski, S.J.; Moir, D.C.

1986-11-15

224

Radiation-induced decomposition of explosives under extreme conditions  

SciTech Connect

We present high-pressure and high temperature studies of the synchrotron radiation-induced decomposition of powder secondary high explosives pentaerythritol tetranitrate (PETN) and 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) using white beam synchrotron radiation at the 16 BM-B and 16 BM-D sectors of the HP-CAT beamline at the Advanced Photon Source. The radiation-induced decomposition rate TATB showed dramatic slowing with pressure up to 26.6 GPa (the highest pressure studied), implying a positive activation volume of the activated complex. The decomposition rate of PETN varied little with pressure up to 15.7 GPa (the highest pressure studied). Diffraction line intensities were measured as a function of time using energy-dispersive methods. By measuring the decomposition rate as a function of pressure and temperature, kinetic and other constants associated with the decomposition reactions were extracted.

Giefers, Hubertus; Pravica, Michael; Yang, Wenge; Liermann, Peter (UNLV); (CIW)

2008-11-03

225

Radiation-induced lung injury: a hypersensitivity pneumonitis  

SciTech Connect

Radiation pneumonitis occurs 6 to 12 weeks after thoracic irradiation, and is thought to be due to direct radiation-induced lung injury. Four patients who developed pneumonitis after unilateral thoracic irradiation for carcinoma of the breast were studied with bronchoalveolar lavage, gallium scan of the lung, and respiratory function tests. On the irradiated side of the chest, all four patients showed an increase in total cells recovered from the lavage fluid and a marked increase in the percentage of lymphocytes. When results for the unirradiated lung were compared with results for the irradiated lung, there was a comparable increase in total cells and percentage of lymphocytes. Gallium scans showed increases for both irradiated and unirradiated lungs. Prompt improvement was seen after corticosteroid therapy in all patients. The fact that abnormal findings occur equally in irradiated and unirradiated lung is inconsistent with simple direct radiation-induced injury and suggests an immunologically mediated mechanism such as a hypersensitivity pneumonitis.

Gibson, P.G.; Bryant, D.H.; Morgan, G.W.; Yeates, M.; Fernandez, V.; Penny, R.; Breit, S.N.

1988-08-15

226

Preliminary studies on radiation-induced changes in chitosan  

NASA Astrophysics Data System (ADS)

Radiation-induced changes in chitosan irradiated in solid state and in aqueous solution were examined. Radiation yields of scission in solid state, determined by HPLC/GPC, are Gs = 0.9 in vacuum, Gs = 1.1 in air and Gs = 1.3 in oxygen; corresponding yields of crosslinking are equal to zero. Increase in absorbance at 247 and 290 nm was observed. Existence of post-effect, i.e. further decrease in molecular weight and increase in absorbance was detected. Radiation-induced changes in solution were studied by pulse radiolysis. Two time-separated first order processes of chain scission were found ( k1 = 1.4 x 10 4 s -1, k2 = 0.58 s -1). Time evolution of absorption spectrum of chitosan macroadicals (? max = 275 nm) was traced.

Ula?ski, P.; Rosiak, J.

227

Modulation of radiation-induced hemopoietic suppression by acute thrombocytopenia  

SciTech Connect

Modifications of radiation-induced hemopoietic suppression by acute thrombocytopenia were evaluated. Immediately before or after exposure to sublethal irradiation, mice were given a single injection of anti-mouse platelet serum (APS), normal heterologous serum, neuraminidase (N'ase), or saline, or no further treatment was provided. Hemopoiesis was evaluated by blood cell counts, hematocrits, and incorporation of (75Se)selenomethionine into platelets. APS and N'ase induced an acute thrombocytopenia from which there was partial recovery before the platelet count started to fall from the radiation. During the second post-treatment week, both thrombocytopoiesis and erythropoiesis were greater in mice that received APS or N'ase in addition to radiation than in control irradiated mice. Differences in leukopoiesis were not apparent. Therefore, both thrombocytopoiesis and erythropoiesis appeared to be responsive to a stimulus generated by acute thrombocytopenia in sublethally irradiated mice.

Ebbe, S.; Phalen, E.; Threatte, G.; Londe, H.

1985-01-01

228

Photocurrent Enhancement Induced By Interface Modifications Due To Low Dose Electron Irradiation Of Amorphous/Crystalline Silicon Heterojunctions  

SciTech Connect

A series of n-type amorphous silicon/p-type crystalline silicon solar cells has been exposed to different fluences of 1 MeV electrons. For intermediate fluences up to 1.10{sup 13} electrons/cm{sup 2}, an enhancement of the spectral response at shorter wavelengths and a increase of the short circuit current has been observed, while for higher fluences the usual device degradation due to the decrease of the charge carrier diffusion length in the crystalline silicon base after irradiation has been found.

Neitzert, Heinz-Christoph; Ferrara, Manuela [DIIIE, Universita di Salerno, Via Ponte Don Melillo 1, 84084 Fisciano (Saudi Arabia) (Italy); Fahrner, Wolfgang; Scherff, Maximilian [Chair of Electronic Devices, University Hagen, Haldener Str. 182, 58084 Hagen (Germany); Klaver, Arjen; Swaaij, Rene van [DIMES-ECTM, Delft University of Technology, P.O. Box 5053, 2600 GB Delft (Netherlands)

2010-01-04

229

The influence of infrared radiation on short-term ultraviolet-radiation-induced injuries  

SciTech Connect

Because heat has been reported to influence adversely short- and long-term ultraviolet (UV)-radiation-induced skin damage in animals, we investigated the short-term effects of infrared radiation on sunburn and on phototoxic reactions to topical methoxsalen and anthracene in human volunteers. Prior heating of the skin caused suppression of the phototoxic response to methoxsalen as evidenced by an increase in the threshold erythema dose. Heat administered either before or after exposure to UV radiation had no detectable influence on sunburn erythema or on phototoxic reactions provoked by anthracene.

Kaidbey, K.H.; Witkowski, T.A.; Kligman, A.M.

1982-05-01

230

Radiation induced absorption in PCS and all silica optical fibres  

NASA Astrophysics Data System (ADS)

From the point of view of radiation hardness, pure synthetic silica is one of the best materials for use in the core of a step-index fiber, taking into account the 0.8-micron wavelength region. Two kinds of fibers have been proposed, including fibers with plastic cladding (PCS) and fibers with doped silica cladding (all silica fibers). The present investigation is concerned with absorption induced by X-ray radiation or high-energy electrons in the 0.8-micron wavelength region. A comparison is conducted regarding the radiation damage suffered by PCS fibers and all silica fibers. It is found that at a wavelength of 0.8 microns the PCS fiber shows much less radiation damage than the all silica fiber.

Torquet de Beauregard, G.; Guillaume, F.; Delay, P.; Noel, G.; Negre, J. P.

1984-01-01

231

Radiation-induced transient attenuation of PCS fiber  

SciTech Connect

Some applications of optical fibers require their exposure to intense radiation fields. This exposure can potentially degrade performance of a fiber data link. Research at Los Alamos National Laboratory has recently concentrated on development of an understanding of such radiation effects at short times, less than 100 ns. In previous papers we have identified a particular type of fiber, ITT plastic-clad-silica (PCS) with Suprasil core as optimum for short time radiation-induced attenuation, but that work used very large doses of ionizing radiation, close to 1 Mrad. For these high dose exposures, moderate success in understanding the transient nature of the attenuation was realized with a geminate recombination model. In this paper, we report further studies with ITT PCS fiber over a range of doses and wavelengths. Data on other PCS fibers is included that provide performance comparable to the ITT product. Comparison to several fluorsilicate fibers is also included.

Lyons, P.B.; Looney, L.D.; Ogle, J.W.

1983-01-01

232

Radiation-induced DNA damage and chromatin structure  

NASA Technical Reports Server (NTRS)

DNA lesions induced by ionizing radiation in cells are clustered and not randomly distributed. For low linear energy transfer (LET) radiation this clustering occurs mainly on the small scales of DNA molecules and nucleosomes. For example, experimental evidence suggests that both strands of DNA on the nucleosomal surface can be damaged in single events and that this damage occurs with a 10-bp modulation because of protection by histones. For high LET radiation, clustering also occurs on a larger scale and depends on chromatin organization. A particularly significant clustering occurs when an ionizing particle traverses the 30 nm chromatin fiber with generation of heavily damaged DNA regions with an average size of about 2 kbp. On an even larger scale, high LET radiation can produce several DNA double-strand breaks in closer proximity than expected from randomness. It is suggested that this increases the probability of misrejoining of DNA ends and generation of lethal chromosome aberrations.

Rydberg, B.; Chatterjee, A. (Principal Investigator)

2001-01-01

233

Probiotic Therapy in Radiation-Induced Intestinal Injury and Repair  

PubMed Central

Intestinal injury from ionizing radiation is a clinically important entity, as enteritis symptoms occur commonly after radiotherapy for pelvic malignancies. Preventative or therapeutic options for radiation enteritis are mostly unsatisfactory; however, available data suggests that probiotic bacteria—those which confer health benefit—may have therapeutic value. Previous reports from both human trials and animal models have evaluated various end points for probiotic usage in limiting radiation-associated intestinal damage. Newer data suggests that particular probiotics and/or their secreted or derived bacterial products may have unique radioprotective properties. We will review the area with a focus on new developments surrounding probiotic therapy in radiation-induced intestinal injury and repair.

Ciorba, Matthew A.; Stenson, William F.

2014-01-01

234

Mechanisms of radiation-induced gene responses  

SciTech Connect

In the process of identifying genes differentially expressed in cells exposed ultraviolet radiation, we have identified a transcript having a 26-bp region that is highly conserved in a variety of species including Bacillus circulans, yeast, pumpkin, Drosophila, mouse, and man. When the 5` region (flanking region or UTR) of a gene, the sequence is predominantly in +/+ orientation with respect to the coding DNA strand; while in the coding region and the 3` region (UTR), the sequence is most frequently in the +/-orientation with respect to the coding DNA strand. In two genes, the element is split into two parts; however, in most cases, it is found only once but with a minimum of 11 consecutive nucleotides precisely depicting the original sequence. The element is found in a large number of different genes with diverse functions (from human ras p21 to B. circulans chitonase). Gel shift assays demonstrated the presence of a protein in HeLa cell extracts that binds to the sense and antisense single-stranded consensus oligomers, as well as to the double- stranded oligonucleotide. When double-stranded oligomer was used, the size shift demonstrated as additional protein-oligomer complex larger than the one bound to either sense or antisense single-stranded consensus oligomers alone. It is speculated either that this element binds to protein(s) important in maintaining DNA is a single-stranded orientation for transcription or, alternatively that this element is important in the transcription-coupled DNA repair process.

Woloschak, G.E.; Paunesku, T.

1996-10-01

235

Radiation-induced genomic instability and bystander effects: inter-related nontargeted effects of exposure to ionizing radiation  

Microsoft Academic Search

The paradigm of genetic alterations being restricted to direct DNA damage after exposure to ionizing radiation has been challenged by observations in which cells that are not exposed to ionizing radiation exhibit responses typically associated with direct radiation exposure. These effects are demonstrated in cells that are the descendants of irradiated cells (radiation-induced genomic instability) or in cells that are

Sally A Lorimore; Philip J Coates; Eric G Wright

2003-01-01

236

Radiation-induced mesotheliomas in rats  

SciTech Connect

Mesotheliomas have been reported in rats that inhaled plutonium, but these tumors have not been extensively studied. To investigate a possible role for inhaled radionuclides in the induction of mesotheliomas, four life-span studies conducted at the Inhalation Toxicology Research Institute are reviewed. A total of 3076 F344 rats were exposed by inhalation to aerosols of {sup 239}PuO{sub 2}, mixed uranium-plutonium oxide, or {sup 144}CeO{sub 2}. Results showed that a low incidence of pleural mesotheliomas was induced by either alpha- or beta-emitting radionuclides deposited and retained in the lung. Chronic alpha irradiation was more effective per unit dose in producing mesotheliomas than chronic beta irradiation of the lung by a factor of 15. 7 refs., 1 tab., 7 figs. (MHB)

Hahn, F.F.; Haley, P.J.; Hubbs, A.F.; Hoover, M.D.; Lundgren, D.L.

1990-01-01

237

Defects induced in fluorides and oxides by VUV radiation  

NASA Astrophysics Data System (ADS)

Irradiation effects of monochromatic VUV were studied in some broad band crystals such as alkaline-earth and perovskite-type fluorides as well as metal oxides. The irradiations were carried out at RT and at LNT and the thermal stability of some radiation-induced defects was studied. Results were compared to effects induced in the same samples by X or radiation. The various types of investigated crystals showed some interesting common properties. In most materials, essentially the same main TL peaks and with the same thermal activation energies appeared after VUV as after X or irradiation, indicating that the same traps were induced by the different irradiations. The TL excitation spectra in the various types of crystals generally showed maxima at the long wavelength tail of the fundamental absorption; this fits previous results in various alkali halides. Dosimetric properties and possible application of the materials as dosimeters for the VUV were also investigated.

Kristianpoller, N.; Weiss, D.; Chen, R.

2005-01-01

238

[Update - health risks induced by ionizing radiation from diagnostic imaging].  

PubMed

Ionizing radiation is the most thoroughly investigated exogenous noxa. Since the early 20th century it is well known that using ionizing radiation in diagnostic procedures causes cancer - physicians themselves frequently being struck by this disease in those early days of radiology. Radiation protection therefore plays an important role. Below doses of 100 Millisievert (mSv) however much research has to be accomplished yet because not only malignant tumors, but cardiovascular diseases, malformations and genetic sequelae attributable to low dose radiation have been described. Unborns, children and adolescents are highly vulnerable. Dose response correlations are subject to continuing discussions because data stem mostly from calculations studying Japanese atomic bomb survivors. Radiation exposure is not exactly known, and it is unknown, if observations of radiation induced diseases in this ethnicity can be generalized. Nowadays the main source of low dose ionizing radiation from medical diagnostics is due to computertomography (CT). Large recent clinical studies from the UK and Australia investigating cancer incidence after exposition to CT in childhood and adolescence confirm that low doses in the range of 5 mSv already significantly increase the risk of malignant diseases during follow up. Imaging techniques as ultrasound and magnetic resonance tomography therefore should be preferred whenever appropriate. PMID:24297861

Knüsli, Claudio; Walter, Martin

2013-12-01

239

Radiation induced oxidative damage modification by cholesterol in liposomal membrane  

NASA Astrophysics Data System (ADS)

Ionizing radiation induced structural and chemical alterations in egg lecithin liposomal membrane have been studied by measurements of lipid peroxides, conjugated diene and fluorescence polarization. Predominantly unilamellar phospholipid vesicles prepared by sonication procedure were subjected to radiation doses of ?-rays from Co-60 in aerated, buffered aqueous suspensions. The oxidative damage in irradiated lipid molecules of liposomes has been determined spectrophotometrically by diene conjugate formation and thiobarbituric acid reactive (TBAR) method as a function of radiation dose. A correlation was found between the radiation dose applied (0.1-1 kGy) and the consequent lipid oxidation. The damage produced in irradiated liposomal membrane was measured by 1,6-diphenyl-1,3,5-hexatriene (DPH) fluorescence decay and polarization. The observed decrease in DPH fluorescence and increase in polarization was found dependent on the radiation dose suggesting alterations in rigidity or organizational order in phospholipid bilayer after irradiation. Furthermore, irradiated liposome vesicles composed of cholesterol showed marked reduction in observed radiation mediated peroxide formation and significantly affected the DPH fluorescence parameters. The magnitude of these modifying effects were found dependent on the mole fraction of cholesterol. It is concluded that modulation of structural order in unilamellar vesicle membrane by variations in basic molecular components controlled the magnitude of lipid peroxidation and diene conjugate formation. These observations contribute to our understanding of mechanism of radical reaction mediated damage caused by ionizing radiation in phospholipid membrane.

Pandey, B. N.; Mishra, K. P.

1999-05-01

240

Aging masks detection of radiation-induced brain injury  

PubMed Central

Fractionated partial or whole-brain irradiation (fWBI) is a widely used, effective treatment for primary and metastatic brain tumors, but it also produces radiation-induced brain injury, including cognitive impairment. Radiation-induced neural changes are particularly problematic for elderly brain tumor survivors who also experience age-dependent cognitive impairment. Accordingly, we investigated, i] radiation-induced cognitive impairment, and ii] potential biomarkers of radiation-induced brain injury in a rat model of aging. Fischer 344 × Brown Norway rats received fractionated whole-brain irradiation (fWBI rats, 40 Gy, 8 fractions over 4 wk) or sham-irradiation (Sham-IR rats) at 12 months of age; all analyses were performed at 26–30 months of age. Spatial learning and memory were measured using the Morris water maze (MWM), hippocampal metabolites were measured using proton magnetic resonance spectroscopy (1H MRS), and hippocampal glutamate receptor subunits were evaluated using Western blots. Young rats (7–10 month-old) were included to control for age effects. The results revealed that both Sham-IR and fWBI rats exhibited age-dependent impairments in MWM performance; fWBI induced additional impairments in the reversal MWM. 1H MRS revealed age-dependent decreases in neuronal markers, increases in glial markers, but no detectable fWBI-dependent changes. Western blot analysis revealed age-dependent, but not fWBI-dependent, glutamate subunit declines. Although previous studies demonstrated fWBI-induced changes in cognition, glutamate subunits, and brain metabolites in younger rats, age-dependent changes in these parameters appear to mask their detection in old rats, a phenomenon also likely to occur in elderly fWBI patients >70 years of age.

Shi, Lei; Olson, John; D'Agostino, Ralph; Linville, Constance; Nicolle, Michelle M.; Robbins, Michael E.; Wheeler, Kenneth T.; Brunso-Bechtold, Judy K.

2011-01-01

241

A mechanistic model for radiation-induced crystallization and amorphization in U 3Si  

NASA Astrophysics Data System (ADS)

Of concern for the proposed Advanced Neutron Source and Research Reactors, which would use intermetallic fuels, are potential radiation-induced phenomena that could affect the physical and mechanical properties of intermetallic aluminum dispersion fuels. For this reason and because of observations of radiation-induced amorphization of U 3Si during ion irradiation, the phenomenology of radiation-induced amorphization is assessed. A rate theory model is formulated wherein amorphous clusters are formed by the damage event. These clusters are considered centers of expansion (CE), or excess-free-volume zones. Simultaneously, centers of compression (CC) are created in the material. In general, many more CCs are created per ion than CEs. The CCs are local regions of increased density that travel through the material as an elastic (e.g., acoustic) shock wave. The CEs can be annihilated upon contact with a sufficient number of CCs, forming either a crystallized region indistinguishable from the host material, or a region with a slight disorientation (recrystallized grain). Recrystallized grains grow by the accumulation of additional CCs. Full amorphization is calculated on the basis of achieving a volume fraction consistent with the close packing of spherical entities. Amorphization of a recrystallized grain is hindered by the presence of the grain boundary. Preirradiation of U 3Si above the critical temperature for amorphization results in the observed formation of nanometer-size grains. In addition, the subsequent reirradiation of these samples in the same ion flux at temperatures below the critical temperatures shows that the material has developed a resistance to radiation-induced amorphization (i.e., a higher dose is needed to amorphize the preirradiated samples than for those that have not been preirradiated). In the model, it is assumed that grain boundaries act as effective defect sinks, and that enhanced defect annihilation is responsible for retarding amorphization below the critical temperature. The calculations have been validated against data from ion-irradiation experiments with U 3Si. The model has also been applied to the ion-induced motion of the interface between crystalline and amorphous phases of U 3Si. The results of this analysis are compared to data and results of calculations for ion bombardment of Si.

Rest, J.

1995-08-01

242

Crystalline Beams  

NASA Astrophysics Data System (ADS)

Crystalline Beams are ordered stale of an ensemble of ions circulating in a Storage Ring with very small velocity fluctuations. They can be obtained from ordinary warm ion beams with the application of intense cooling techniques, namely electron and/or laser cooling. A phase transition occurs when sufficiently small velocity spreads are reached, freezing the particle-to-particle spacing in strings, zig-zags, and helices... The properties and feasibility of Crystalline Beams depend on the choice of the lattice of the Storage Ring. There are three issues closely related to the design of the Storage Ring, namely: the determination of Equilibrium Configurations, Confinement Conditions, and Stability Conditions. Of particular concern is the effect of the trajectory curvature and of the beam momentum spread. They both set the requirements on the amount of momentum cooling, on the focussing, and on the distribution of bending in the lattice of the Storage Ring. The practical demonstration of Crystalline Beams may create the basis for an advanced technology of particle accelerators. The limitations due to Coulomb intra-beam scattering and space-charge forces would be finally be brought under control, so that ordered beams of ions can be achieved for a variety of new applications.

Ruggiero, Alessandro G.

2000-12-01

243

Radiation-induced transmissable chromosomal instability in haemopoietic stem cells  

NASA Astrophysics Data System (ADS)

Heritable radiation-induced genetic alterations have long been assumed to be ``fixed'' within the first cell division. However, there is a growing body of evidence that a considerable fraction of cells surviving radiation exposure appear normal, but a variety of mutational changes arise in their progeny due to a transmissible genomic instability. In our investigations of G-banded metaphases, non-clonal cytogenetic aberrations, predominantly chromatid-type aberrations, have been observed in the clonal descendants of murine and human haemopoietic stem cells surviving low doses (~1 track per cell) of alpha-particle irradiations. The data are consistent with a transmissible genetic instability induced in a stem cell resulting in a diversity of chromosomal aberrations in its clonal progeny many cell divisions later. Recent studies have demonstrated that the instability phenotype persists in vivo and that the expression of chromosomal instability has a strong dependence on the genetic characteristics of the irradiated cell. At the time when cytogenetic aberrations are detected, an increased incidence of hprt mutations and apoptotic cells have been observed in the clonal descendants of alpha-irradiated murine haemopoietic stem cells. Thus, delayed chromosomal abnormalities, delayed cell death by apoptosis and late-arising specific gene mutations may reflect diverse consequences of radiation-induced genomic instability. The relationship, if any, between these effects is not established. Current studies suggest that expression of these delayed heritable effects is determined by the type of radiation exposure, type of cell and a variety of genetic factors.

Kadhim, M. A.; Wright, E. G.

244

Radiation induced corrosion of copper for spent nuclear fuel storage  

NASA Astrophysics Data System (ADS)

The long term safety of repositories for radioactive waste is one of the main concerns for countries utilizing nuclear power. The integrity of engineered and natural barriers in such repositories must be carefully evaluated in order to minimize the release of radionuclides to the biosphere. One of the most developed concepts of long term storage of spent nuclear fuel is the Swedish KBS-3 method. According to this method, the spent fuel will be sealed inside copper canisters surrounded by bentonite clay and placed 500 m down in stable bedrock. Despite the importance of the process of radiation induced corrosion of copper, relatively few studies have been reported. In this work the effect of the total gamma dose on radiation induced corrosion of copper in anoxic pure water has been studied experimentally. Copper samples submerged in water were exposed to a series of total doses using three different dose rates. Unirradiated samples were used as reference samples throughout. The copper surfaces were examined qualitatively using IRAS and XPS and quantitatively using cathodic reduction. The concentration of copper in solution after irradiation was measured using ICP-AES. The influence of aqueous radiation chemistry on the corrosion process was evaluated based on numerical simulations. The experiments show that the dissolution as well as the oxide layer thickness increase upon radiation. Interestingly, the evaluation using numerical simulations indicates that aqueous radiation chemistry is not the only process driving the corrosion of copper in these systems.

Björkbacka, Åsa; Hosseinpour, Saman; Johnson, Magnus; Leygraf, Christofer; Jonsson, Mats

2013-11-01

245

Radiation-induced skin carcinomas of the head and neck  

SciTech Connect

Radiation exposures to the scalp during childhood for tinea capitis were associated with a fourfold increase in skin cancer, primarily basal cell carcinomas, and a threefold increase in benign skin tumors. Malignant melanoma, however, was not significantly elevated. Overall, 80 neoplasms were identified from an extensive search of the pathology logs of all major hospitals in Israel and computer linkage with the national cancer registry. Radiation dose to the scalp was computed for over 10,000 persons irradiated for ringworm (mean 7 Gy), and incidence rates were contrasted with those observed in 16,000 matched comparison subjects. The relative risk of radiogenic skin cancer did not differ significantly between men or women or by time since exposure; however, risk was greatest following exposures in early childhood. After adjusting for sex, ethnic origin, and attained age, the estimated excess relative risk was 0.7 per Gy and the average excess risk over the current follow-up was 0.31/10(4) PY-Gy. The risk per Gy of radiation-induced skin cancer was intermediate between the high risk found among whites and no risk found among blacks in a similar study conducted in New York City. This finding suggests the role that subsequent exposure to uv radiation likely plays in the expression of a potential radiation-induced skin malignancy.

Ron, E.; Modan, B.; Preston, D.; Alfandary, E.; Stovall, M.; Boice, J.D. Jr. (National Cancer Institute, Bethesda, MD (USA))

1991-03-01

246

Induced movements of giant vesicles by millimeter wave radiation.  

PubMed

Our previous study of interaction between low intensity radiation at 53.37GHz and cell-size system - such as giant vesicles - indicated that a vectorial movement of vesicles was induced. This effect among others, i.e. elongation, induced diffusion of fluorescent dye di-8-ANEPPS, and increased attractions between vesicles was attributed to the action of the field on charged and dipolar residues located at the membrane-water interface. In an attempt to improve the understanding on how millimeter wave radiation (MMW) can induce this movement we report here a real time evaluation of changes induced on the movement of giant vesicles. Direct optical observations of vesicles subjected to irradiation enabled the monitoring in real time of the response of vesicles. Changes of the direction of vesicle movement are demonstrated, which occur only during irradiation with a "switch on" of the effect. This MMW-induced effect was observed at a larger extent on giant vesicles prepared with negatively charged phospholipids. The monitoring of induced-by-irradiation temperature variation and numerical dosimetry indicate that the observed effects in vesicle movement cannot be attributed to local heating. PMID:24704354

Albini, Martina; Dinarelli, Simone; Pennella, Francesco; Romeo, Stefania; Zampetti, Emiliano; Girasole, Marco; Morbiducci, Umberto; Massa, Rita; Ramundo-Orlando, Alfonsina

2014-07-01

247

Simulation of Nucleation Kinetics of Radiation-Induced Defect Clusters in Irradiated Materials.  

National Technical Information Service (NTIS)

A numerical method for simulation kinetics of radiation-induced defect clusters in irradiated materials is developed. Calculations of nucleation kinetics of radiation-induced defect clusters under pulsed irradiation corresponding to continuous irradiation...

A. I. Ryazanov A. D. Sidorenko S. S. Filippov

1985-01-01

248

Radiation-pressure-induced mechano-optical bistability.  

PubMed

We suggest and analyze a new radiation-pressure-induced bistability: A planar waveguide is suspended to swing as a torsional pendulum. A laser beam is coupled into the waveguide by a grating input coupler at one end of the waveguide and is outcoupled at the other end. The incoupling efficiency has a sharp angular resonance. When the pendulum is initially detuned from resonance, the torque exerted by the radiation pressure tends to drive it into resonance. The torque is proportional to the incoupling efficiency; therefore it depends on the angular position of the pendulum. This feedback leads to the mechano-optical bistability. PMID:19724373

Lukosz, W

1985-03-01

249

[Interest of blood markers in predicting radiation-induced toxicity].  

PubMed

The oncologic outcome and the total dose are highly correlated with the treatment by ionizing radiation. The dose increase (total or per fraction) may provoke late-side effects that are potentially irreversible. The radiation-induced CD8 lymphocyte apoptotic value and the molecular modifications within the lymphocyte are capable of predicting the level of risk of developing late-side effects after curative intent radiotherapy. In this review, we present the different blood assays in this setting and discuss the current possibilities of researches, namely those involving the proteomic process. PMID:21676639

Lacombe, J; Solassol, J; Coelho, M; Ozsahin, M; Azria, D

2011-08-01

250

The radiation-induced changes in rectal mucosa: Hyperfractionated vs. hypofractionated preoperative radiation for rectal cancer  

SciTech Connect

Purpose: The purpose of the study was the qualitative and quantitative evaluation of acute radiation-induced rectal changes in patients who underwent preoperative radiotherapy according to two different irradiation protocols. Patients and Methods: Sixty-eight patients with rectal adenocarcinoma underwent preoperative radiotherapy; 44 and 24 patients underwent hyperfractionated and hypofractionated protocol, respectively. Fifteen patients treated with surgery alone served as a control group. Five basic histopathologic features (meganucleosis, inflammatory infiltrations, eosinophils, mucus secretion, and erosions) and two additional features (mitotic figures and architectural glandular abnormalities) of radiation-induced changes were qualified and quantified. Results: Acute radiation-induced reactions were found in 66 patients. The most common were eosinophilic and plasma-cell inflammatory infiltrations (65 patients), erosions, and decreased mucus secretion (54 patients). Meganucleosis and mitotic figures were more common in patients who underwent hyperfractionated radiotherapy. The least common were the glandular architectural distortions, especially in patients treated with hypofractionated radiotherapy. Statistically significant differences in morphologic parameters studied between groups treated with different irradiation protocols were found. Conclusion: The system of assessment is a valuable tool in the evaluation of radiation-induced changes in the rectal mucosa. A greater intensity of regenerative changes was found in patients treated with hyperfractionated radiotherapy.

Starzewski, Jacek J. [Department of General and Colorectal Surgery, Medical University of Silesia, Sosnowiec (Poland); Pajak, Jacek T. [Department of Pathology, Medical University of Silesia, Katowice (Poland); Pawelczyk, Iwona [Department of General and Colorectal Surgery, Medical University of Silesia, Sosnowiec (Poland); Lange, Dariusz [Department of Tumor Pathology, Comprehensive Cancer Center Division, Gliwice (Poland); Golka, Dariusz [Department of Pathology, Medical University of Silesia, Katowice (Poland)]. E-mail: dargolka@wp.pl; Brzeziska, Monika [Department of General and Colorectal Surgery, Medical University of Silesia, Sosnowiec (Poland); Lorenc, Zbigniew [Department of General and Colorectal Surgery, Medical University of Silesia, Sosnowiec (Poland)

2006-03-01

251

Effects of crystallinity on laser-induced voltage effect from Zn0.9Co0.1O thin film  

NASA Astrophysics Data System (ADS)

Co-doped ZnO epilayer films were grown by pulsed laser deposition (PLD) on vicinal cut silicon and sapphire substrates. Changes in deposition time were observed as a moderate effect on the quality of the films, and the influence of the thickness on thermoelectric signals from Zn0.9Co0.1O thin films were discussed. The effect of one of the main deposition parameters, the deposition time, on the crystallinity and electron mobility properties of the Zn0.9Co0.1O thin films grown on sapphire was investigated by means of X-ray diffraction (XRD) and laser-induced voltage (LIV) effect. It shown that the XRD rocking curve full-width half-maximun (FWHM) decreased as time increasing, and the LIV signals were observed along the tilting angle of the substrate orientation when the pulsed KrF excimer laser of 248 nm were irradiated on the films. When the films illuminated in pulse lasers, the highest signals occurred in the films with best crystalline quality, and the signals were higher in the films grown on sapphire than those on silicon substrates. It suggested that the electrical resistivity and electron mobility have close relations with not only the crystallinity but also with the interface of the thin films.

Zhou, X. F.; Lu, M. H.; Zhang, H.; Yan, H.; He, C. L.; Hao, R. Y.

2013-11-01

252

Radiation-quality-dependent bystander effects induced by the microbeams with different radiation sources  

PubMed Central

A central paradigm in radiation biology has been that only cells ‘hit’ by a track of radiation would be affected to induce radiobiological consequences, and cells ‘not hit’ should not be. This is the basis of the current system for risk estimation of radiobiological effects. However, it has recently been challenged by so-called non-targeted effects, such as bystander effect, and such radiation-induced cellular responses may have important implications for risk evaluation of low-dose-rate radiations as well as in tumor radiotherapy. Our group has been studying radiation-quality bystander cellular effects using the microbeams with different radiation sources. It is essentially important for evaluating risk such a low-dose-rate exposure as the accident of Fukushima Daiichi Nuclear Power Plants to examine bystander effects induced by low-LET electromagnetic radiations, such as X or gamma rays. We have been studying the cellular responses in normal human fibroblasts by targeted cell nucleus irradiations with monochromatic X-ray microbeams (5.35 keV) produced by Photon Factory in High Energy Accelerator Research Organization. The results indicated that the bystander effect in cell- killing effect was observed in the targeted cell nucleus irradiation, not in the random irradiation containing both cell nucleus and cytoplasm by Poisson distribution. The results suggest that energy deposition in cytoplasm is an important role of inducing bystander effects in case of low-LET radiations. We have also been investigating high-LET-radiation induced bystander effects using the heavy-ion microbeams at Takasaki Ion Accelerators for Advanced Radiation Application in Japan Atomic Energy Agency. Only 0.04% of the total numbers of normal human fibroblasts were irradiated with C-ion (220 MeV), Ne-ion (260 MeV) and Ar-ion (460 MeV) microbeams collimated at 20 ?m in diameter. Cell-killing effect and gene mutation at HPRT locus in the cells irradiated with C ions were higher beyond our expectations and returned the estimated values that only 0.04% of the total cells were irradiated when using the specific inhibitor of gap junctions. On the other hand, no induced biological effects were observed in Ne and Ar ions whether the inhibitor was applied or not. The result suggested that the C-ion microbeam was capable of inducing bystander cellular effects via gap junction-mediated cell-cell communication. There is clear evidence that bystander cellular effects are dependent on radiation quality. It is also important for highly developed heavy-ion radiotherapy to identify bystander effects induced by spatially low-fluence irradiations with heavy-ion beams. We have been investigating the biological effects using human tumor cell lines. The results clearly showed that bystander effects were observed in the carbon-ion irradiation but not in other ions as well as the effects in normal fibroblasts. Furthermore, the bystander cell-killing effect in tumor cell lines was strongly induced in the cells harboring wild-type P53 not in mutated-type P53 cells. The results provide the important implication for a tailor-made therapy using carbon ions.

Suzuki, M.; Autsavapromporn, N.; Usami, N.; Funayama, T.; Plante, I.; Yokota, Y.; Mutou; Suzuki, M.; Ikeda, H.; Hattori, Y.; Kobayashi, K.; Kobayashi, Y.; Murakami, T.

2014-01-01

253

Simulation of shear wave propagation induced by acoustic radiation force  

NASA Astrophysics Data System (ADS)

Acoustic radiation force is a physical phenomenon caused by propagation of ultrasound in an attenuating medium. When ultrasound propagates in the medium, the momentum of propagating ultrasound is transferred to the medium due to absorption mechanism. As a result, acoustic radiation force is generated in the principal direction of waves. By focusing the ultrasound at a specific location for a certain period, we can exert the acoustic radiation force at the location and generate the source of the shear waves. Characteristics of the shear wave critically depend on the material properties. Therefore, the shear wave propagation in the medium containing an inclusion shows differences compared to the wave in the pure medium. We simulate acoustic radiation force and generate shear waves by using the finite element method. The purpose of this study is to simulate the effect of the radiation force and to estimate the properties of the inclusion through analyzing the change of the shear wave induced by the radiation force in the almost incompressible materials.

Jung, Jae-Wook; Hong, Jung-Wuk; Lee, Hyoung-Ki; Choi, Kiwan

2014-04-01

254

Factors influencing the yield of radiation induced electron spin resonance (ESR) signal in lamb bones  

Microsoft Academic Search

Irradiation treatment of bone-in meat chunks induced a characteristic ESR signal in the bone tissue. Effect of various processing parameters such as bone type, absorbed radiation dose, irradiation temperature, cooking prior to irradiation and post irradiation cooking on the intensity of radiation induced ESR signal was studied. It was observed that intensity of radiation induced signal was higher in leg

S. P Chawla; Paul Thomas; D. R Bongirwar

2002-01-01

255

Opportunities for nutritional amelioration of radiation-induced cellular damage  

NASA Technical Reports Server (NTRS)

The closed environment and limited evasive capabilities inherent in space flight cause astronauts to be exposed to many potential harmful agents (chemical contaminants in the environment and cosmic radiation exposure). Current power systems used to achieve space flight are prohibitively expensive for supporting the weight requirements to fully shield astronauts from cosmic radiation. Therefore, radiation poses a major, currently unresolvable risk for astronauts, especially for long-duration space flights. The major detrimental radiation effects that are of primary concern for long-duration space flights are damage to the lens of the eye, damage to the immune system, damage to the central nervous system, and cancer. In addition to the direct damage to biological molecules in cells, radiation exposure induces oxidative damage. Many natural antioxidants, whether consumed before or after radiation exposure, are able to confer some level of radioprotection. In addition to achieving beneficial effects from long-known antioxidants such as vitamins E and C and folic acid, some protection is conferred by several recently discovered antioxidant molecules, such as flavonoids, epigallocatechin, and other polyphenols. Somewhat counterintuitive is the protection provided by diets containing elevated levels of omega-3 polyunsaturated fatty acids, considering they are thought to be prone to peroxidation. Even with the information we have at our disposal, it will be difficult to predict the types of dietary modifications that can best reduce the risk of radiation exposure to astronauts, those living on Earth, or those enduring diagnostic or therapeutic radiation exposure. Much more work must be done in humans, whether on Earth or, preferably, in space, before we are able to make concrete recommendations.

Turner, Nancy D.; Braby, Leslie A.; Ford, John; Lupton, Joanne R.

2002-01-01

256

Pyridoxamine protects intestinal epithelium from ionizing radiation-induced apoptosis  

PubMed Central

Reactive oxygen species (ROS) and reactive carbonyl species (RCS) are the major cause of biological tissue damage during the exposure to ionizing radiation (IR). The existing strategies to protect normal tissues from detrimental effects of IR suffer from several shortcomings including high toxic side effects, unfavorable administration routs or low efficacy. These shortcomings emphasize a need for radioprotective treatments that combine effectiveness with safety and ease of use. In this paper, we demonstrate that pyridoxamine, a ROS and RCS scavenger with a very favorable safety profile, can inhibit IR-induced gastrointestinal endothelial apoptosis in cell culture and in animal model. Pyridoxamine was more effective at protecting from radiation-induced apoptosis compared to Amifostine, a synthetic thiol compound and the only FDA approved radioprotector. We suggest that PM has a potential as an effective and safe radioprotective agent.

Thotala, Dinesh; Chetyrkin, Sergei; Hudson, Billy; Hallahan, Dennis; Voziyan, Paul; Yazlovitskaya, Eugenia

2009-01-01

257

Radiation-induced coordination topological defects in chalcogenide glasses  

NASA Astrophysics Data System (ADS)

The radiation-induced (gamma-quanta of Co-60 source) coordination topological defect formation in chalcogenide glasses of quasi-binary AS(2)S(3)-GeS2 system is studied using experimental techniques of IR Fourier spectroscopy and positron annihilation lifetime measurements. The new model of open-volume microvoids connected with negatively charged under-coordinated defects is developed at the basis of the obtained results.

Shpotyuk, O. I.; Filipecki, J.; Kozdras, A.; Balitska, V.

2003-01-01

258

Effect of Sobatum on radiation-induced toxicity in mice  

Microsoft Academic Search

Sobatum, the active fraction of the plant Solanum trilobatum was obtained from the petroleum ether\\/ethyl acetate (75:25) extractable portion. Sobatum was proven to be an anticancer agent by in vitro and in vivo methods. The aim of this study is to evaluate the effect of Sobatum on radiation-induced toxicity in mice. In this assay there are three groups. Group I,

P. V Mohanan; K. S Devi

1998-01-01

259

Interlaboratory comparison of radiation-induced attenuation in optical fibers  

SciTech Connect

A comparison of the losses induced in step index multimode, graded index multimode and single mode fibers by pulsed radiation exposure has been made among 12 laboratories over a period of 5 years. The recoveries of the incremental attenuations from 10{sup -9} to 10{sup 1} s are reported. Although a standard set of measurement parameters was attempted, differences between the laboratories are evident; possible origins for these are discussed. 18 refs., 18 figs., 7 tabs.

Friebele, E.J.; Lyons, P.B.; Blackburn, J.C.; Henschel, H.; Johan, A.; Krinsky, J.A.; Robinson, A.; Schneider, W.; Smith, D.; Taylor, E.W. (Naval Research Lab., Washington, DC (USA); Los Alamos National Lab., NM (USA); Harry Diamond Labs., Adelphi, MD (USA); Fraunhofer-Institut fuer Naturwissenschaftlich-Technische Trendanalysen (INT), Euskirchen (Germany, F.R.); Direction des Recherches, Etudes et Techni

1989-08-01

260

Radiation-Induced Polymerization of a Series of Vinyl Ethers  

Microsoft Academic Search

The radiation-induced polymerization of methyl, ethyl, isobutyl, isopropyl, and tert-butyl vinyl ethers was studied under super-dry conditions. Methyl vinyl ether did not polymerize at measurable rates; ethyl vinyl ether polymerized readily but with a dose rate dependence of the rate of only 0.3. The other ethers polymerized with a square-root dependence of the rate on the dose rate. Good agreement

A. M. Goineau; J. Kohler; V. Stannett

1977-01-01

261

Proton-induced radiation damage in germanium detectors  

Microsoft Academic Search

High-purity germanium (HPGe) detectors will be used in future space missions for gamma-ray measurements and will be subject to interactions with energetic particles. To simulate this process, several large-volume n-type HPGe detectors were incrementally exposed to a particle fluence of up to 108 protons cm-2 (proton energy: 1.5 GeV) at different operating temperatures (90 to 120 K) to induce radiation

J. Brueckner; M. Koerfer; H. Waenke; A. N. F. Schroeder; D. Filges; P. Dragovitsch; P. A. J. Englert; R. Starr; J. I. Trombka; I. Taylor; D. M. Drake; E. R. Shunk

1991-01-01

262

Radiation-induced transient absorption in single mode optical fibers  

SciTech Connect

This paper reviews the measurements conducted by the Los Alamos National Laboratory in support of these NATO efforts wherein radiation-induced transient absorption was measured over time ranges from a few ns to several ..mu..s for two single mode fibers. Experimental conditions were varied to provide data for future development of standarized test conditions for single mode fibers. 8 refs., 11 figs.

Looney, L.D.; Lyons, P.B.

1988-01-01

263

Radiation-induced decomposition of PETN and TATB under pressure  

NASA Astrophysics Data System (ADS)

We have investigated decomposition of PETN and TATB induced by white synchrotron X-ray radiation in a diamond anvil cell at ambient temperature and two pressures, nearly ambient and about 6 GPa. The decomposition rate of TATB decreases significantly when it is pressurized to 5.9 GPa. The measurements were highly reproducible and allowed us to obtain decomposition rates and the order parameters of the reactions.

Giefers, Hubertus; Pravica, Michael; Liermann, Hanns-Peter; Yang, Wenge

2006-09-01

264

Radiation-induced decomposition of PETN and TATB under pressure  

Microsoft Academic Search

We have investigated decomposition of PETN and TATB induced by white synchrotron X-ray radiation in a diamond anvil cell at ambient temperature and two pressures, nearly ambient and about 6GPa. The decomposition rate of TATB decreases significantly when it is pressurized to 5.9GPa. The measurements were highly reproducible and allowed us to obtain decomposition rates and the order parameters of

Hubertus Giefers; Michael Pravica; Hanns-Peter Liermann; Wenge Yang

2006-01-01

265

Radiation-induced decomposition of PETN and TATB under pressure  

SciTech Connect

We have investigated decomposition of PETN and TATB induced by white synchrotron X-ray radiation in a diamond anvil cell at ambient temperature and two pressures, nearly ambient and about 6 GPa. The decomposition rate of TATB decreases significantly when it is pressurized to 5.9 GPa. The measurements were highly reproducible and allowed us to obtain decomposition rates and the order parameters of the reactions.

Giefers, Hubertus; Pravica, Michael; Liermann, Hanns-Peter; Yang, Wenge (UNLV); (CIW)

2008-10-02

266

Verilog-A Modeling of Radiation-Induced Mismatch Enhancement  

Microsoft Academic Search

Physical model of TID effects is embedded into BSIM3v3 model implemented using Verilog-A. Radiation-induced mismatch enhancement due to the combined action of technology variations and electrical bias difference is demonstrated by sim- ulation. It is shown that the total ionizing dose degradation of circuit components under inequivalent electric field conditions could lead to mismatch of internal circuit parameters, which results

Maxim S. Gorbunov; Igor A. Danilov; Gennady I. Zebrev; Pavel N. Osipenko

2011-01-01

267

Radiation-induced luminescence in terbium-doped silicate glasses  

NASA Astrophysics Data System (ADS)

The purpose of this study is to characterize radiation- induced luminescence of terbium-doped silicate glasses. Experiments performed investigated the optical properties, isothermal time-evolution, and temperature dependence of the radiation-induced luminescence of two commercially available terbium-doped glasses. A problem common to this type of glass is the persistent luminescence, or afterglow, that occurs following the end of excitation from an external source of radiation. While the processes that govern characteristic luminescence of rare earth ions, including terbium, are well understood, the processes that give rise to afterglow in doped glasses are not. Identifying the source of long-term luminescence is essential for controlling problems that may arise from practical applications of luminescent glasses. It was determined that the stimulation of terbium fluorescence is the result of direct excitation from the external radiation source, and indirect excitation from the delayed recombination of charge carriers releasing from traps in the host glass. The range of trap depths is found to be well represented by quasi-continuous distribution functions. The characteristic decay time during the initial response of both glasses studied is approximately 3.5 milliseconds. Decay of the afterglow was observed to persist for several hours, depending on the acquired dose of radiation. Comparison of the response to x-rays and ultraviolet radiation yielded the same results, indicating that the same processes are involved in producing afterglow for both cases. This result suggests a more efficient means of characterizing scintillating glasses by using ultraviolet lasers instead of x-rays.

West, Michael Stuart

1997-12-01

268

Environmental applications of radiation-induced defects in clay minerals  

NASA Astrophysics Data System (ADS)

Radiation effects on clay minerals have been studied over the last 35 years, providing a wealth of information on environmental and geological processes. They have been applied to the reconstruction of past radioelement migrations in the geosphere, the dating of clay minerals from soils or the evolution of the physico-chemical properties under irradiation. All known radiation-induced point defects in clay minerals are detected using Electron Paramagnetic Resonance Spectroscopy. They mostly consist in electron holes located on oxygen atoms of the structure, and can be differentiated through their nature and their thermal stability. For instance, several are associated to a ? orbital on a Si-O bond. One defect, namely the A-center, is stable over geological periods at ambiant temperature. These point defects are produced mainly by ionizing radiations. By contrast to point defects, it was shown that electron or heavy ion irradiation easily produces amorphization in smectites. Two main applications of radiation-induced defects in clay minerals are derived : (i) the use of defects as tracers of past radioactivity. In geosystems where the age of the clay can be constrained, migrations of radioelements can be reconstructed in natural analogues of the far field of high level nuclear waste repositories. When the dose rate may be assumed constant over time, the paleodose is used to date clay populations, an approach applied to laterites of the Amazon basin. (ii) The influence of radiation on clay mineral properties that remains poorly documented, although it is an important issue in various domains such as the safety assessment of the high level nuclear waste repositories. In case of a leakage of transuranic elements from the radioactive wasteform, alpha recoil nuclei would amorphize smectite after a period much lower than the disposal lifetime. By contrast, amorphisation from ionizing radiation is unlikely over 1 million years. Furthermore, it was shown that amorphization greatly enhances the dissolution kinetics of smectite, a result that must be taken into account in the safety assessment of engineered barriers.

Allard, T.

2011-12-01

269

Radiation-induced alterations in mitochondria of the rat heart.  

PubMed

Radiation therapy for the treatment of thoracic cancers may be associated with radiation-induced heart disease (RIHD), especially in long-term cancer survivors. Mechanisms by which radiation causes heart disease are largely unknown. To identify potential long-term contributions of mitochondria in the development of radiation-induced heart disease, we examined the time course of effects of irradiation on cardiac mitochondria. In this study, Sprague-Dawley male rats received image-guided local X irradiation of the heart with a single dose ranging from 3-21 Gy. Two weeks after irradiation, left ventricular mitochondria were isolated to assess the dose-dependency of the mitochondrial permeability transition pore (mPTP) opening in a mitochondrial swelling assay. At time points from 6 h to 9 months after a cardiac dose of 21 Gy, the following analyses were performed: left ventricular Bax and Bcl-2 protein levels; apoptosis; mitochondrial inner membrane potential and mPTP opening; mitochondrial mass and expression of mitophagy mediators Parkin and PTEN induced putative kinase-1 (PINK-1); mitochondrial respiration and protein levels of succinate dehydrogenase A (SDHA); and the 70 kDa subunit of complex II. Local heart irradiation caused a prolonged increase in Bax/Bcl-2 ratio and induced apoptosis between 6 h and 2 weeks. The mitochondrial membrane potential was reduced until 2 weeks, and the calcium-induced mPTP opening was increased from 6 h up to 9 months. An increased mitochondrial mass together with unaltered levels of Parkin suggested that mitophagy did not occur. Lastly, we detected a significant decrease in succinate-driven state 2 respiration in isolated mitochondria from 2 weeks up to 9 months after irradiation, coinciding with reduced mitochondrial levels of succinate dehydrogenase A. Our results suggest that local heart irradiation induces long-term changes in cardiac mitochondrial membrane functions, levels of SDH and state 2 respiration. At any time after exposure to radiation, cardiac mitochondria are more prone to mPTP opening. Future studies will determine whether this makes the heart more susceptible to secondary stressors such as calcium overload or ischemia/reperfusion. PMID:24568130

Sridharan, Vijayalakshmi; Aykin-Burns, Nukhet; Tripathi, Preeti; Krager, Kimberly J; Sharma, Sunil K; Moros, Eduardo G; Corry, Peter M; Nowak, Grazyna; Hauer-Jensen, Martin; Boerma, Marjan

2014-03-01

270

Adaptive radiation-induced epigenetic alterations mitigated by antioxidants  

PubMed Central

Humans are exposed to low-dose ionizing radiation (LDIR) from a number of environmental and medical sources. In addition to inducing genetic mutations, there is concern that LDIR may also alter the epigenome. Such heritable effects early in life can either be positively adaptive or result in the enhanced formation of diseases, including cancer, diabetes, and obesity. Herein, we show that LDIR significantly increased DNA methylation at the viable yellow agouti (Avy) locus in a sex-specific manner (P=0.004). Average DNA methylation was significantly increased in male offspring exposed to doses between 0.7 and 7.6 cGy, with maximum effects at 1.4 and 3.0 cGy (P<0.01). Offspring coat color was concomitantly shifted toward pseudoagouti (P<0.01). Maternal dietary antioxidant supplementation mitigated both the DNA methylation changes and coat color shift in the irradiated offspring. Thus, LDIR exposure during gestation elicits epigenetic alterations that lead to positive adaptive phenotypic changes that are negated with antioxidants, indicating they are mediated in part by oxidative stress. These findings provide evidence that in the isogenic Avy mouse model, epigenetic alterations resulting from LDIR play a role in radiation hormesis, bringing into question the assumption that every dose of radiation is harmful.—Bernal, A. J., Dolinoy, D. C., Huang, D., Skaar, D. A., Weinhouse, C., Jirtle, R. J. Adaptive radiation-induced epigenetic alterations mitigated by antioxidants.

Bernal, Autumn J.; Dolinoy, Dana C.; Huang, Dale; Skaar, David A.; Weinhouse, Caren; Jirtle, Randy L.

2013-01-01

271

Radiation induced CNS toxicity - molecular and cellular mechanisms  

PubMed Central

Radiotherapy of tumours proximal to normal CNS structures is limited by the sensitivity of the normal tissue. Prior to the development of prophylactic strategies or treatment protocols a detailed understanding of the mechanisms of radiation induced CNS toxicity is mandatory. Histological analysis of irradiated CNS specimens defines possible target structures prior to a delineation of cellular and molecular mechanisms. Several lesions can be distinguished: Demyelination, proliferative and degenerative glial reactions, endothelial cell loss and capillary occlusion. All changes are likely to result from complex alterations within several functional CNS compartments. Thus, a single mechanism responsible cannot be separated. At least four factors contribute to the development of CNS toxicity: (1) damage to vessel structures; (2) deletion of oligodendrocyte-2 astrocyte progenitors (O-2A) and mature oligodendrocytes; (3) deletion of neural stem cell populations in the hippocampus, cerebellum and cortex; (4) generalized alterations of cytokine expression. Several underlying cellular and molecular mechanisms involved in radiation induced CNS toxicity have been identified. The article reviews the currently available data on the cellular and molecular basis of radiation induced CNS side effects. ??http://www.bjcancer.com © 2001 Cancer Research Campaign

Belka, C; Budach, W; Kortmann, R D; Bamberg, M

2001-01-01

272

[Radiation-induced sequelae: toward an individual profile].  

PubMed

The impact of curative radiotherapy depends mainly on the total dose delivered homogenously in the targeted volume. Nevertheless, the dose delivery is limited by the tolerated dose of the surrounding healthy tissues. Two different side effects (acute and late) can occur during and after radiotherapy. Of particular interest are the radiation-induced sequelae due to their irreversibility and the potential impact on daily quality of life. In a population treated in one center with the same technique, it appears that individual radiosensitivity clearly exists. In the hypothesis that genetic is involved in this area of research, lymphocytes seem to be the tissue of choice due to easy accessibility. Recently, low percentage of CD4 and CD8 lymphocyte apoptosis were shown to be correlated with high grade of sequelae. In addition, recent data suggest that patients with severe radiation-induced late side effects possess four or more SNP in candidate genes (ATM, SOD2, TGFB1, XRCC1 et XRCC3) and low radiation-induced CD8 lymphocyte apoptosis in vitro. PMID:18757226

Azria, D; Belkacemi, Y; Lagrange, J-L; Chapet, O; Mornex, F; Maingon, P; Hennequin, C; Rosenstein, B; Ozsahin, M

2008-11-01

273

Identifying patients at risk for late radiation-induced toxicity.  

PubMed

The impact of curative radiotherapy depends mainly on the total dose delivered in the targeted volume. Nevertheless, the dose delivered to the surrounding healthy tissues may reduce the therapeutic ratio of many treatments. Two different side effects (acute and late) can occur during and after radiotherapy. Of particular interest are the radiation-induced late complications (LC) due to their irreversibility and the potential impact on quality of life. In one population treated with the same technique, it appears that individual radiosensitivity clearly exists. In the hypothesis that genetic is involved in this area of research, low CD4 and CD8 lymphocyte apoptosis were shown to be correlated with high grade of LC. In addition, recent data suggest that patients with severe radiation-induced LC possess 4 or more single nucleotide polymorphisms (SNPs) in candidate genes and low radiation-induced CD8 lymphocyte apoptosis in vitro. On-going studies are being analyzing the entire genome using a genome-wide association study (GWAS). PMID:20869261

Azria, D; Betz, M; Bourgier, C; Jeanneret Sozzi, W; Ozsahin, M

2012-12-01

274

Radiation-induced grain boundary segregation in austenitic stainless steels  

SciTech Connect

Radiation-induced segregation (RIS) to grain boundaries in Fe-Ni-Cr-Si stainless alloys has been measured as a function of irradiation temperature and dose. Heavy-ion irradiation was used to produce damage levels from 1 to 20 displacements per atom (dpa) at temperatures from 175 to 550{degrees}C. Measured Fe, Ni, and Cr segregation increased sharply with irradiation dose (from G to 5 dpa) and temperature (from 175 to about 350{degrees}C). However, grain boundary concentrations did not change significantly as dose or temperatures were further increased. Although interfacial compositions were similar, the width of radiation-induced enrichment or depletion profiles increased consistently with increasing dose or temperature. Impurity segregation (Si and P) was also measured, but only Si enrichment appeared to be radiation-induced. Grain boundary Si peaked at levels approaching 10 at% after irradiation doses to 10 dpa at an intermediate temperature of 325{degrees}C. No evidence of grain boundary silicide precipitation was detected after irradiation at any temperature. Equilibrium segregation of P was measured in the high-P alloys, but interfacial concentration did not increase with irradiation exposure. Comparisons to reported RIS in neutron-irradiated stainless steels revealed similar grain boundary compositional changes for both major alloying and impurity elements.

Bruemmer, S.M.; Charlot, L.A.; Vetrano, J.S.; Simonen, E.P.

1994-11-01

275

Radiation induced bystander effects: Implications for low dose radiation risk assessment  

NASA Astrophysics Data System (ADS)

Current model used in radiation risk assessment is based on the dogma that the DNA of the nucleus is the main target for radiation-induced genotoxicity and, as fewer cells are directly damaged at low doses, the deleterious effects of radiation proportionally decline. Using a precision microbeam to target an exact fraction of cells in a population and irradiated their nuclei with exactly one alpha particle each, we found that the frequencies of induced mutations and chromosomal changes in populations where some known fractions of nuclei were hit are consistent with non- hit cells contributing significantly to the response. In fact, irradiation of 10% of a mammalian cell population with a single alpha particle per cell results in a mutant yield similar to that observed when all of the cells in the population are irradiated. This effect was significantly eliminated in cells pretreated with gap junction inhibitor or in cells carrying a dominant negative connexin 43 vector. The data imply that the relevant target for radiation mutagenesis is larger than an individual cell and suggest a need to reconsider the validity of the linear extrapolation in making risk estimate for low dose radiation exposure.

Zhou, H.; Suzuki, M.; Randers-Pehrson, G.; Waldren, C.; Hei, T.

276

Method for increased sensitivity of radiation detection and measurement  

DOEpatents

Dose of radiation to which a body of crystalline material has been exposed is measured by exposing the body to optical radiation at a first wavelength, which is greater than about 540 nm, and measuring optical energy emitted from the body by luminescence at a second wavelength, which is longer than the first wavelength. Reduced background is accomplished by more thorough annealing and enhanced radiation induced luminescence is obtained by treating the crystalline material to coalesce primary damage centers into secondary damage centers.

Miller, Steven D. (Richland, WA)

1994-01-01

277

Thin-Film Photovoltaic Radiation Testing for Space Applications  

Microsoft Academic Search

Although thin-film photovoltaic technology on lightweight flexible substrates has lower beginning-of-life efficiency compared to traditional single crystalline solar cells, it can offer advantages in high-specific power and low-stowed volume for power generation in space. To date, radiation testing on thin-film solar cells has demonstrated superior radiation hardness compared to traditional crystalline solar cells. In addition, radiation induced damage in thin-film

S. H. Liu; J. E. Granata; J. C. Nocerino; J. S. Halpine; E. J. Simburger

2006-01-01

278

Quantifying Local Radiation-Induced Lung Damage From Computed Tomography  

SciTech Connect

Purpose: Optimal implementation of new radiotherapy techniques requires accurate predictive models for normal tissue complications. Since clinically used dose distributions are nonuniform, local tissue damage needs to be measured and related to local tissue dose. In lung, radiation-induced damage results in density changes that have been measured by computed tomography (CT) imaging noninvasively, but not yet on a localized scale. Therefore, the aim of the present study was to develop a method for quantification of local radiation-induced lung tissue damage using CT. Methods and Materials: CT images of the thorax were made 8 and 26 weeks after irradiation of 100%, 75%, 50%, and 25% lung volume of rats. Local lung tissue structure (S{sub L}) was quantified from local mean and local standard deviation of the CT density in Hounsfield units in 1-mm{sup 3} subvolumes. The relation of changes in S{sub L} (DELTAS{sub L}) to histologic changes and breathing rate was investigated. Feasibility for clinical application was tested by applying the method to CT images of a patient with non-small-cell lung carcinoma and investigating the local dose-effect relationship of DELTAS{sub L}. Results: In rats, a clear dose-response relationship of DELTAS{sub L} was observed at different time points after radiation. Furthermore, DELTAS{sub L} correlated strongly to histologic endpoints (infiltrates and inflammatory cells) and breathing rate. In the patient, progressive local dose-dependent increases in DELTAS{sub L} were observed. Conclusion: We developed a method to quantify local radiation-induced tissue damage in the lung using CT. This method can be used in the development of more accurate predictive models for normal tissue complications.

Ghobadi, Ghazaleh; Hogeweg, Laurens E. [Department of Radiation Oncology, University Medical Center Groningen/University of Groningen, Groningen (Netherlands); Faber, Hette [Department of Radiation Oncology, University Medical Center Groningen/University of Groningen, Groningen (Netherlands); Department of Cell Biology, Section of Radiation and Stress Cell Biology, University Medical Center Groningen/University of Groningen, Groningen (Netherlands); Tukker, Wim G.J. [Department of Radiology, University Medical Center Groningen/University of Groningen, Groningen (Netherlands); Schippers, Jacobus M. [Department of Radiation Oncology, University Medical Center Groningen/University of Groningen, Groningen (Netherlands); Accelerator Department, Paul Scherrer Institut, Villigen (Switzerland); Brandenburg, Sytze [Kernfysisch Versneller Instituut, Groningen (Netherlands); Langendijk, Johannes A. [Department of Radiation Oncology, University Medical Center Groningen/University of Groningen, Groningen (Netherlands); Coppes, Robert P. [Department of Radiation Oncology, University Medical Center Groningen/University of Groningen, Groningen (Netherlands); Department of Cell Biology, Section of Radiation and Stress Cell Biology, University Medical Center Groningen/University of Groningen, Groningen (Netherlands); Luijk, Peter van, E-mail: p.van.luijk@rt.umcg.n [Department of Radiation Oncology, University Medical Center Groningen/University of Groningen, Groningen (Netherlands)

2010-02-01

279

In-Situ Measurement of Crystalline Silicon Modules Undergoing Potential-Induced Degradation in Damp Heat Stress Testing for Estimation of Low-Light Power Performance  

SciTech Connect

The extent of potential-induced degradation of crystalline silicon modules in an environmental chamber is estimated using in-situ dark I-V measurements and applying superposition analysis. The dark I-V curves are shown to correctly give the module power performance at 200, 600 and 1,000 W/m2 irradiance conditions, as verified with a solar simulator. The onset of degradation measured in low light in relation to that under one sun irradiance can be clearly seen in the module design examined; the time to 5% relative degradation measured in low light (200 W/m2) was 28% less than that of full sun (1,000 W/m2 irradiance). The power of modules undergoing potential-induced degradation can therefore be characterized in the chamber, facilitating statistical analyses and lifetime forecasting.

Hacke, P.; Terwilliger, K.; Kurtz, S.

2013-08-01

280

Periodic models in quantum chemical simulations of F centers in crystalline metal oxides  

Microsoft Academic Search

We present a survey of recent first principles simulations of the neutral oxygen vacancies (F centers) existing as native or radiation-induced point defects in various crystalline metal oxides in different forms (bulk, bare substrate surface, and on the interface with metal adsorbates). We mainly consider periodic models in calculations of point defects using the metal oxide supercell or cyclic clusters.

Yuri F. Zhukovskii; Eugene A. Kotomin; Robert A. Evarestov; Donald E. Ellis

2007-01-01

281

Differences between heat and radiation damage in radiation-induced fibrosarcomas  

SciTech Connect

The growth delays induced in murine fibrosarcomas exposed to either single, graded doses of X-irradiation or exposures to 44.5 degrees C for various lengths of time were compared. Tumor regrowth rates after X-irradiation showed a dose-dependent reduction in growth rate; those after heat were indistinguishable from controls. Growth delay after radiation exposure increased linearly up to the maximum dose given (5,000 rad). Heating became progressively less effective in inducing additional delay; the delay measured after 60 minutes was only slightly greater than that seen after 30 minutes at 44.5 degrees C.

Faria, S.L.; Hahn, G.M.

1982-06-01

282

Should Cancer Survivors Fear Radiation-Induced Sarcomas?  

PubMed Central

Purpose/Results. Ionizing radiation is carcinogenic and the induction of a second malignancy is a serious potential long-term complication of radiotherapy. The incidence of radiation-induced sarcomas was evaluated from many large epidemiological surveys of long-term cancer survivors reported in the literature over the past 30 years and only one case was found for every 1000 patients irradiated. Discussion. Although greater numbers of cancer patients are receiving radical radiotherapy and surviving free of disease for longer intervals, cases of radiation-induced sarcomas are rare and should not deter patients from accepting radiotherapy as treatment for curable cancers. With improvements in the administration of radiotherapy over the past two decades which are resulting in less damage to bone and soft tissues, it is likely that fewer cases of this condition will be seen in the future. If these sarcomas are diagnosed early, long-term survival can be achieved with surgical excision and possibly re-irradiation, as occurs in other types of sarcomas.

1997-01-01

283

Pharmacological Protection From Radiation {+-} Cisplatin-Induced Oral Mucositis  

SciTech Connect

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, {approx}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 Multiplication-Sign 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.

Cotrim, Ana P. [Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD (United States); Yoshikawa, Masanobu [Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD (United States); Department of Clinical Pharmacology, Tokai University School of Medicine, Kanagawa (Japan); Sunshine, Abraham N.; Zheng Changyu [Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD (United States); Sowers, Anastasia L.; Thetford, Angela D.; Cook, John A.; Mitchell, James B. [Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD (United States); Baum, Bruce J., E-mail: bbaum@dir.nidcr.nih.gov [Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD (United States)

2012-07-15

284

Secondary Ultraweak Luminescence from Humic Acids Induced by ?-Radiation  

PubMed Central

Humic substances (HSs) are products of biochemical transformations of plant and animal residues that make up a major fraction of the organic carbon of soil and aquatic systems in the environment. Because radioisotopes occur in the Earth’s crust and because the entire biosphere is continuously exposed to cosmic radiation, ionizing radiation continually interacts with HSs. This chronic irradiation could have a significant ecological impact. However, very few publications are available that address possible consequences of chronic exposure of HSs to ionizing radiation from terrestrial and cosmic sources. This study was conducted to investigate possible impacts of exposure of HSs to ionizing radiation. Dried humic acid (HA) or its associated aqueous solution (in 0.1 M Na2CO3) were exposed to absorbed ?-radiation in high doses of 1–90 kGy using a 60Co source. Following the ?-ray exposures, a secondary, ultraweak radiation emanation with wavelengths in the spectral range ?= 340–650 nm was recorded as a long-lived chemiluminescence (CL) from the aqueous solutions; however, the CL was not observed after irradiating dry HA. Absorption spectra (for ?=240–800 nm) of irradiated solutions indicated that polymerization/degradation processes were operating on the HA macromolecules. The effect of specific CL enhancers (luminol and lucigenin) on the intensity and kinetics of the CL implicated the participation of reactive oxygen species and free radicals in the CL and polymerization/degradation processes. For the range of absorbed doses used (1–10 kGy), the intensity of the induced CL was nonlinearly related to dose, suggesting that complex radical formation mechanisms were involved.

Goraczko, Wieslaw; Slawinski, Janusz

2004-01-01

285

Ultraviolet-A radiation induces changes in cyclin G gene expression in mouse melanoma B16-F1 cells  

PubMed Central

Background We have previously shown that ultraviolet-A (UVA) radiation enhances metastatic lung colonization capacity of B16-F1 melanoma cells. The aim of this study was to examine changes in expression profile of genes in mouse melanoma B16-F1 cells exposed to UVA radiation. Results B16-F1 melanoma cells were exposed to a single UVA radiation dose of 8 J/cm2 and mRNA was isolated 4 h after the end of UVA exposure. Atlas™ Mouse Cancer 1.2 cDNA expression arrays were used for the large-scale screening to identify the genes involved in the regulation of carcinogenesis, tumor progression and metastasis. Physiologically relevant UVA dose induced differential expression in 9 genes in the UVA exposed melanoma cells as compared to the unexposed control cells. The expression of seven genes out of nine was upregulated (HSC70, HSP86, ?-B-crystallin, GST mu2, Oxidative stress induced protein OSI, VEGF, cyclin G), whereas the expression of two genes was down-regulated (G-actin, non-muscle cofilin). The gene expression of cyclin G was mostly affected by UVA radiation, increasing by 4.85-folds 4 hour after exposure. The analysis of cyclin G protein expression revealed 1.36-fold increase at the 6 hour time point after UVA exposure. Cell cycle arrest in G2/M phase, which is known to be regulated by cyclin G, occurred at 4-h hour time-point, peaking 8 hours after the end of UVA irradiation, suggesting that cyclin G might play a role in the cell cycle arrest. Conclusion Our results suggest that UVA radiation-induces changes in the expression of several genes. Some of these changes, e.g. in expression of cyclin G, possibly might affect cell physiology (cell cycle arrest).

Pastila, Riikka; Leszczynski, Dariusz

2007-01-01

286

Cerenkov emission induced by external beam radiation stimulates molecular fluorescence  

PubMed Central

Purpose: Cerenkov emission is induced when a charged particle moves faster than the speed of light in a given medium. Both x-ray photons and electrons produce optical Cerenkov photons in everyday radiation therapy of tissue; yet, this phenomenon has never been fully documented. This study quantifies the emissions and also demonstrates that the Cerenkov emission can excite a fluorophore, protoporphyrin IX (PpIX), embedded in biological phantoms.Methods: In this study, Cerenkov emission induced by radiation from a clinical linear accelerator is investigated. Biological mimicking phantoms were irradiated with x-ray photons, with energies of 6 or 18 MV, or electrons at energies 6, 9, 12, 15, or 18 MeV. The Cerenkov emission and the induced molecular fluorescence were detected by a camera or a spectrometer equipped with a fiber optic cable.Results: It is shown that both x-ray photons and electrons, at MeV energies, produce optical Cerenkov photons in tissue mimicking media. Furthermore, we demonstrate that the Cerenkov emission can excite a fluorophore, protoporphyrin IX (PpIX), embedded in biological phantoms.Conclusions: The results here indicate that molecular fluorescence monitoring during external beam radiotherapy is possible.

Axelsson, Johan; Davis, Scott C.; Gladstone, David J.; Pogue, Brian W.

2011-01-01

287

Cerenkov emission induced by external beam radiation stimulates molecular fluorescence  

SciTech Connect

Purpose: Cerenkov emission is induced when a charged particle moves faster than the speed of light in a given medium. Both x-ray photons and electrons produce optical Cerenkov photons in everyday radiation therapy of tissue; yet, this phenomenon has never been fully documented. This study quantifies the emissions and also demonstrates that the Cerenkov emission can excite a fluorophore, protoporphyrin IX (PpIX), embedded in biological phantoms. Methods: In this study, Cerenkov emission induced by radiation from a clinical linear accelerator is investigated. Biological mimicking phantoms were irradiated with x-ray photons, with energies of 6 or 18 MV, or electrons at energies 6, 9, 12, 15, or 18 MeV. The Cerenkov emission and the induced molecular fluorescence were detected by a camera or a spectrometer equipped with a fiber optic cable. Results: It is shown that both x-ray photons and electrons, at MeV energies, produce optical Cerenkov photons in tissue mimicking media. Furthermore, we demonstrate that the Cerenkov emission can excite a fluorophore, protoporphyrin IX (PpIX), embedded in biological phantoms. Conclusions: The results here indicate that molecular fluorescence monitoring during external beam radiotherapy is possible.

Axelsson, Johan; Davis, Scott C.; Gladstone, David J.; Pogue, Brian W. [Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755 (United States); Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire 03766 (United States); Thayer School of Engineering and Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire 03755 (United States)

2011-07-15

288

Radiation Induces Osteogenesis in Human Aortic Valve Interstitial Cells  

PubMed Central

Objective Irradiation of the chest or chest wall has been shown to caause calcific aortic stenosis. However, the mechanisms are unknown. Aortic valve interstitial cells (AVICs) have been implicated in the pathogenesis of aortic stenosis; they have been shown to change from the phenotype of a myofibroblast to an osteoblast-like cell. We therefore hypothesized that irradiation of human AVICs induces an osteogenic phenotype. In isolated human AVICs, our purpose was to determine the effect of irradiation on the production of osteogenic factors: (a) bone morphogenetic protein-2 (BMP-2) (b) osteopontin (OPN) (c) alkaline phosphatase (ALP), and (d) the transcription factor Runx2. Methods Human AVICs were isolated from normal aortic valves obtained from explanted hearts of patients undergoing cardiac transplantation (n=4) and grown in culture. The cells were grown to confluence, irradiated with 10 Gy using a cesium-137 irradiator and then lysed 24 hours following irradiation. Cell lysates were analyzed via immunoblot and densitometry for BMP-2, OPN, ALP and Runx2. Statistics were by ANOVA. P < 0.05 was significant. Results Irradiation induced an osteogenic phenotype in human AVICs. Irradiation induced a 2-fold increase in BMP-2, a 7-fold increase in OPN, a 3-fold increase in ALP, and a 2-fold increase in Runx2. Conclusions Radiation induces an osteogenic phenotype in human AVICs. The irradiated cells had significantly increased expression of the osteogenic factors BMP-2, OPN, ALP and Runx2. These data offer mechanistic insight into the pathogenesis of radiation-induced valvular heart disease.

Nadlonek, Nicole A; Weyant, Michael J; Yu, Jessica A; Cleveland, Joseph C; Reece, T Brett; Meng, Xianzhong; Fullerton, David A.

2012-01-01

289

DNA damage induced by the direct effect of radiation  

NASA Astrophysics Data System (ADS)

We have studied the nature of DNA damage induced by the direct effect of radiation. The yields of single- (SSB) and double-strand breaks (DSB), base lesions and clustered damage were measured using the agarose gel electrophoresis method after exposing to various kinds of radiations to a simple model DNA molecule, fully hydrated closed-circular plasmid DNA (pUC18). The yield of SSB does not show significant dependence on linear energy transfer (LET) values. On the other hand, the yields of base lesions revealed by enzymatic probes, endonuclease III (Nth) and formamidopyrimidine DNA glycosylase (Fpg), which excise base lesions and leave a nick at the damage site, strongly depend on LET values. Soft X-ray photon (150 kVp) irradiation gives a maximum yield of the base lesions detected by the enzymatic probes as SSB and clustered damage, which is composed of one base lesion and proximate other base lesions or SSBs. The clustered damage is visualized as an enzymatically induced DSB. The yields of the enzymatically additional damages strikingly decrease with increasing levels of LET. These results suggest that in higher LET regions, the repair enzymes used as probes are compromised because of the dense damage clustering. The studies using simple plasmid DNA as a irradiation sample, however, have a technical difficulty to detect multiple SSBs in a plasmid DNA. To detect the additional SSBs induced in opposite strand of the first SSB, we have also developed a novel technique of DNA-denaturation assay. This allows us to detect multiply induced SSBs in both strand of DNA, but not induced DSB.

Yokoya, A.; Shikazono, N.; Fujii, K.; Urushibara, A.; Akamatsu, K.; Watanabe, R.

2008-10-01

290

Solar radiation induced rotational bursting of interplanetary particles  

NASA Technical Reports Server (NTRS)

It is suggested that the magnitudes of the two radiation-induced rotational bursting mechanisms (Radzieskii effect and windmill effect) have been overestimated and that they do not work significantly faster than the Poynting-Robertson effect in removing interplanetary particles. These two mechanisms are described, and serious doubts are raised regarding the derivation of their radiation pressure-torque proportionality constants, which are required for calculating their magnitudes. It is shown that both mechanisms will cause the alignment of elongated particles and, consequently, the polarization of zodiacal light. Since no positive polarization has been measured at the antisolar point, it is concluded that the magnitudes of the rotational bursting mechanisms are smaller than that of the Poynting-Robertson effect.

Sparrow, J. G.

1975-01-01

291

Radiation-induced hydroperoxidation of oleic acid on silica gel  

NASA Astrophysics Data System (ADS)

Radiation-induced hydroperoxidation of oleic acid in bulk liquid, in multiple liquid layers on glass and in silica gel coated with O1 proceed by a chain mechanism. Two propagation steps in the formation of OlOOH could be identified in bulk liquid, as well as in adsorbed layers: reaction with oxygen and chain transfer reaction. Consequently, radiation chemical yields of hydroperoxidation, G(OlOOH), are influenced by both, the availability of oxygen and by the presence of chain-breaking antioxidants. Besides scavenging precursors to OlOOH, ?-tocopherol also reacts with OlOOH formed in monolayers by irradiation. Adsorbed layers of oleic acid behave as two-dimensional liquids.

Katušin-Ražem, Branka; Ražem, Dušan

1996-03-01

292

Radiation induced grafting of acrylic acid onto extruded polystyrene surface  

NASA Astrophysics Data System (ADS)

Polystyrene materials with good solubility in liquid scintillation cocktails are used to wipe off different types of surfaces in order to determine the tritium removable contamination with the help of a liquid scintillation counter. This paper analyses hydrophilic surface modifications by radiation induced grafting of acrylic groups onto extruded polystyrene plates. Two grafting methods were used: (a) exposure of extruded polystyrene plates, immersed in aqueous acrylic acid solution, to a gamma radiation of a Co-60 source, and (b) exposure of extruded polystyrene plates to a Co-60 source, followed by the immersion of extruded polystyrene plates in aqueous acrylic acid solution. The grafting of acrylic was proved by IR spectrometry and by radiometric methods using acrylic acid labelled with tritium.

Fugaru, Viorel; Bubueanu, George; Tuta, Catalin

2012-09-01

293

Treatment of radiation- and chemotherapy-induced stomatitis  

SciTech Connect

Severe stomatitis is a common problem encountered during either radiation therapy or chemotherapy. Most therapeutic regimens are empirical, with no scientific basis. The purpose of this study is to determine the efficacy of various topical solutions in the treatment of radiation- or chemotherapy-induced stomatitis. Eighteen patients were entered into a prospective double-blinded study to test several topical solutions: (1) viscous lidocaine with 1% cocaine; (2) dyclonine hydrochloride 1.0% (Dyclone); (3) kaolin-pectin solution, diphenhydramine plus saline (KBS); and (4) a placebo solution. Degree of pain relief, duration of relief, side effects, and palatability were evaluated. The results showed that Dyclone provided the most pain relief. Dyclone and viscous lidocaine with 1% cocaine provided the longest pain relief, which averaged 50 minutes This study provides objective data and defines useful guidelines for treatment of stomatitis.

Carnel, S.B.; Blakeslee, D.B.; Oswald, S.G.; Barnes, M. (Fitzsimons Army Medical Center, Aurora, CO (USA))

1990-04-01

294

Thermal instability of a fluid layer induced by radiation  

SciTech Connect

In this paper the thermal instability of a fluid layer above a solid boundary induced by incident radiative heat to the upper free surface is studied numerically. Eddington approximation is adopted for the equation of transfer, and the pseudospectral method is used to solve the linearized perturbed equations. The effects of Planck number, optical thickness, Biot number, emissivity of the lower plate, and transmissivity of the upper surface on the transition are analyzed for gray and nonscattering fluids. In general, decreasing the temperature difference between the lower plate and the upper surface by increasing the Planck number and the optical thickness, and by decreasing the emissivity and the transmissivity at fixed Biot number, delays the onset of instability. Biot number plays a unique role for nonradiating fluids, and dual roles for radiating fluids on the occurrence of instability.

Yang, W.M. (Dept. of Mechanical Engineering, National Chiao Tung Univ., HsinchU 30049 (TW))

1990-01-01

295

Mechanisms of radiation-induced sensorineural hearing loss and radioprotection.  

PubMed

Patients that receive radiotherapy are at risk of late sensorineural hearing loss when the inner ear is included within the radiation field. Preclinical and human temporal bone studies have shown that there is differential damage to cochlear structures depending on the amount of dose delivered to the inner ear. In vitro studies have suggested that reactive oxygen species (ROS) are the main initial actors in radiation-induced damage. The interaction of ROS with different cellular components can result in different apoptotic pathways. Therefore, approaches to radioprotection are mainly aimed to reduce ROS production through antioxidants. This review summarizes recent research in the field that can improve the understanding and boost preventive efforts of this adverse effect. PMID:24650954

Mujica-Mota, Mario A; Lehnert, Shirley; Devic, Slobodan; Gasbarrino, Karina; Daniel, Sam J

2014-06-01

296

Changes induced by UV radiation during virgin olive oil storage.  

PubMed

The effects of UV radiation on the chemical and sensory characteristics of virgin olive oils (cv. Arbequina and Picual) were assessed. Even small doses of UV radiation induced oxidation of the virgin olive oil samples. Total phenols and fatty acids contents decreased during the process as well as the intensity of the bitter and fruity sensory attributes, while the intensity of the rancid sensory attribute notably increased. Acetaldehyde, 2-butenal, 2-pentenal, octane, octanal, hexanal, nonanal, and 2-decenal were the volatile compounds most affected, showing an important increase during the irradiation process. Nonanal, hexanal, and pentanal showed high correlation with the rancid sensory attribute (90%, 86%, and 86%, respectively). 2-Decenal and nonanal concentrations allowed us to predict the alteration level of the samples by mean of multiple Ridge regression. PMID:16787029

Luna, G; Morales, M T; Aparicio, R

2006-06-28

297

Ion-beam mixing in crystalline and amorphous germanium isotope multilayers  

SciTech Connect

Gallium (Ga) implantation induced self-atom mixing in crystalline and amorphous germanium (Ge) is investigated utilizing isotopically controlled Ge multilayer structures grown by molecular beam epitaxy. The distribution of the Ga ions and the ion-beam induced depth-dependent mixing of the isotope structure was determined by means of secondary ion mass spectrometry. Whereas the distribution of Ga in the crystalline and amorphous Ge is very similar and accurately reproduced by computer simulations based on binary collision approximation (BCA), the ion-beam induced self-atom mixing is found to depend strongly on the state of the Ge structure. The experiments reveal stronger self-atom mixing in crystalline than in amorphous Ge. Atomistic simulations based on BCA reproduce the experimental results only when unphysically low Ge displacement energies are assumed. Analysis of the self-atom mixing induced by silicon implantation confirms the low displacement energy deduced within the BCA approach. This demonstrates that thermal spike mixing contributes significantly to the overall mixing of the Ge isotope structures. The disparity observed in the ion-beam mixing efficiency of crystalline and amorphous Ge indicates different dominant mixing mechanisms. We propose that self-atom mixing in crystalline Ge is mainly controlled by radiation enhanced diffusion during the early stage of mixing before the crystalline structure turns amorphous, whereas in an already amorphous state self-atom mixing is mediated by cooperative diffusion events.

Bracht, H.; Radek, M.; Kube, R.; Knebel, S. [Institut fuer Materialphysik, Westfaelische Wilhelms-Universitaet Muenster, 48149 Muenster (Germany); Posselt, M.; Schmidt, B. [Helmholtz-Zentrum Dresden-Rossendorf, 01314 Dresden (Germany); Haller, E. E. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Bougeard, D. [Institut fuer Experimentelle und Angewandte Physik, 93040 Regensburg (Germany)

2011-11-01

298

Radiation Induced Sarcoma of Oral Cavity-A Rare Case Report and a Short Review  

PubMed Central

Radiation - Induced Sarcomas(RIS) are rare clinical entity. They arise from the previously irradiated areas with a prolonged latency period. In this case report we present a rare case of radiation induced sarcoma with a brief review of literature. We report radiation-induced sarcoma in a 67–year–old male, involving the left Retromolar Trigone region following treatment of squamous cell carcinoma of tongue with wide excision, neck dissection and post-operative radiation. Diagnosis of radiation induced sarcoma was confirmed by history, latency period and biopsy.

Ganesan, Sivaraman; Iype, Elizabeth Mathew; Kapali, Aravind S.; S., Renu

2013-01-01

299

?-Tocopherol succinate protects mice against radiation-induced gastrointestinal injury.  

PubMed

The purpose of this study was to elucidate the role of ?-tocopherol succinate (?-TS) in protecting mice from gastrointestinal syndrome induced by total-body irradiation. CD2F1 mice were injected subcutaneously with 400 mg/kg of ?-TS and exposed to different doses of (60)Co ? radiation, and 30-day survival was monitored. Jejunum sections were analyzed for crypts and villi, PUMA (p53 upregulated modulator of apoptosis), and apoptosis (terminal deoxynucleotidyl transferase dUTP nick end labeling - TUNEL). The crypt regeneration in irradiated mice was evaluated by 5-bromo-2-deoxyuridine (BrdU). Bacterial translocation from gut to heart, spleen and liver in ?-TS-treated and irradiated mice was evaluated by bacterial culture on sheep blood agar, colistin-nalidixic acid, and xylose-lysine-desoxycholate medium. Our results demonstrate that ?-TS enhanced survival in a significant number of mice irradiated with 9.5, 10, 11 and 11.5 Gy (60)Co ? radiation when administered 24 h before radiation exposure. ?-TS also protected the intestinal tissue of irradiated mice in terms of crypt and villus number, villus length and mitotic figures. TS treatment decreased the number of TUNEL- and PUMA-positive cells and increased the number of BrdU-positive cells in jejunum compared to vehicle-treated mice. Further, ?-TS inhibited gut bacterial translocation to the heart, spleen and liver in irradiated mice. Our data suggest that ?-TS protects mice from radiation-induced gastrointestinal damage by inhibiting apoptosis, promoting regeneration of crypt cells, and inhibiting translocation of gut bacteria. PMID:22013885

Singh, Pankaj K; Wise, Stephen Y; Ducey, Elizabeth J; Fatanmi, Oluseyi O; Elliott, Thomas B; Singh, Vijay K

2012-02-01

300

Involvement of Prostaglandins and Histamine in Radiation-Induced Temperature Responses in Rats.  

National Technical Information Service (NTIS)

Exposure of rats to Gy of gamma radiation induced hypothermia, whereas exposure to 20-150 Gy produced hypothermia. Since radiation exposure included the release of prostaglandins (PGs) and histamine, the role of PGs and histamine in radiation-induced temp...

S. B. Kandasamy W. A. Hunt

1990-01-01

301

Radiation induced failures of complementary metal oxide semiconductor containing pacemakers: a potentially lethal complication  

Microsoft Academic Search

New multi-programmable pacemakers frequently employ complementary metal oxide semiconductors (CMOS). This circuitry appears more sensitive to the effects of ionizing radiation when compared to the semiconductor circuits used in older pacemakers. A case of radiation induced runaway pacemaker in a CMOS device is described. Because of this and other recent reports of radiation therapy-induced CMOS type pacemaker failure, these pacemakers

Alan A. Lewin; Christopher F. Serago; James G. Schwade; Andre A. Abitbol; Stephen C. Margolis

1984-01-01

302

Strain-induced macroscopic magnetic anisotropy from smectic liquid-crystalline elastomer-maghemite nanoparticle hybrid nanocomposites.  

PubMed

We combine tensile strength analysis and X-ray scattering experiments to establish a detailed understanding of the microstructural coupling between liquid-crystalline elastomer (LCE) networks and embedded magnetic core-shell ellipsoidal nanoparticles (NPs). We study the structural and magnetic re-organization at different deformations and NP loadings, and the associated shape and magnetic memory features. In the quantitative analysis of a stretching process, the effect of the incorporated NPs on the smectic LCE is found to be prominent during the reorientation of the smectic domains and the softening of the nanocomposite. Under deformation, the soft response of the nanocomposite material allows the organization of the nanoparticles to yield a permanent macroscopically anisotropic magnetic material. Independent of the particle loading, the shape-memory properties and the smectic phase of the LCEs are preserved. Detailed studies on the magnetic properties demonstrate that the collective ensemble of individual particles is responsible for the macroscopic magnetic features of the nanocomposite. PMID:23677459

Haberl, Johannes M; Sánchez-Ferrer, Antoni; Mihut, Adriana M; Dietsch, Hervé; Hirt, Ann M; Mezzenga, Raffaele

2013-06-21

303

Measurements of prompt radiation induced conductivity of Kapton.  

SciTech Connect

We performed measurements of the prompt radiation induced conductivity in thin samples of Kapton (polyimide) at the Little Mountain Medusa LINAC facility in Ogden, UT. Three mil samples were irradiated with a 0.5 {mu}s pulse of 20 MeV electrons, yielding dose rates of 1E9 to 1E10 rad/s. We applied variable potentials up to 2 kV across the samples and measured the prompt conduction current. Analysis rendered prompt conductivity coefficients between 6E-17 and 2E-16 mhos/m per rad/s, depending on the dose rate and the pulse width.

Preston, Eric F. (ITT Corporation, Colorado Springs, CO); Zarick, Thomas Andrew; Sheridan, Timothy J.; Hartman, E. Frederick; Stringer, Thomas Arthur (ITT Corporation, Colorado Springs, CO)

2010-10-01

304

Radiation therapy induces the DNA damage response in peripheral blood  

PubMed Central

Stereotactic body radiation therapy (SBRT) is a radiotherapy modality that delivers highly conformal, ablative doses to a well-defined target. Here, using a semiquantitative multiplexed assay to analyze ATM and H2AX phosphorylation, we show that ATM kinase activity in peripheral blood mononuclear cells is induced following SBRT. This observation of a systemic ATM kinase-dependent DNA damage response in the peripheral blood is unprecedented and promotes the use of ATM serine-1981 phosphorylation as a predictive biomarker for DNA damaging modalities and ATM inhibitors.

Bakkenist, Christopher J.; Czambel, R. Kenneth; Clump, David A.; Greenberger, Joel S.; Beumer, Jan H.; Schmitz, John C.

2013-01-01

305

Radiation-induced morphoea treated with UVA-1 phototherapy.  

PubMed

Morphoea is a localized inflammatory disorder of the dermis and subcutaneous fat and radiotherapy is a rarely reported cause (estimated incidence of 2 per 1000). Morphoea is commonly mistaken for an inflammatory recurrence of breast cancer, resulting in unnecessary investigations and treatment. We report the case of a 40-year-old woman who developed radiation-induced morphoea of the breast 7 months following adjuvant radiotherapy. She was treated with topical and systemic steroids as well as psoralen plus ultraviolet (UV)A before proceeding to UVA1 phototherapy. We also review the literature and discuss other management options. PMID:24890985

Lim, D; Johnston, S; Novakovic, L; Fearfield, L

2014-07-01

306

Radiation-induced differential optical absorption of metal nanoparticles  

NASA Astrophysics Data System (ADS)

A method of measuring the temperature of metal nanoparticles under ion bombardment is proposed. Optical absorption in the range of the surface plasmon resonance of metal nanoparticles was measured during implantation of 3 MeV Cu2+ ions into silica glass to derive a difference in optical absorption between beam on and off regimes. The radiation-induced differential (RD) spectra were similar to the spectra of thermomodulation (TM) and quite different from the spectra of nonlinear optical response measured by the pump-probe method. Increasing amplitude of RD and TM spectra was assigned to an increase of lattice temperature of Cu nanoparticles.

Plaksin, Oleg; Takeda, Yoshihiko; Amekura, Hiroshi; Kishimoto, Naoki

2006-05-01

307

Internally consistent model for radiation-induced void swelling  

SciTech Connect

Most previous analytical models for radiation-induced void swelling employed reaction rate theory in which all concentrations were averaged out. Here a unified, internally consistent analytical approach is presented which incorporates the presence of dislocations, voids, and grain boundaries each with their own spatially varying diffusional fields. The results show large variations in sink strength Z-factors, usually treated as constants, significant variations in the void swelling bias factor, and quantitative levels of bias about an order of magnitude larger than most previous estimates. Good qualitative agreement is shown with available data, consistent with current concepts of close-pair annihilation in high-energy damage cascades.

Nichols, F.A.; Liu, Y.Y.

1981-01-01

308

Investigation Into Radiation-Induced Compaction of Zerodur (trademark)  

SciTech Connect

Zerodur is a low coefficient of thermal expansion glass-ceramic material. This property makes Zerodur an excellent material for high precision optical substrates. Functioning as a high precision optical substrate, a material must be dimensionally stable in the system operating environment. Published data indicate that Zerodur is dimensionally unstable when exposed to large doses of ionizing radiation. The dimensional instability is discussed as an increase in Zerodur density. This increase in density is described as a compaction. Experimental data showing proton-induced compaction of Zerodur is presented. The dependence of compaction on proton dose was determined to be a power law relationship.

Edwards, D.L.; Herren, K.; Hayden, M.; Mcdonald, K.; Sims, J.A.; Semmel, C.L.

1996-03-01

309

Galactic cosmic ray-induced radiation dose on terrestrial exoplanets.  

PubMed

This past decade has seen tremendous advancements in the study of extrasolar planets. Observations are now made with increasing sophistication from both ground- and space-based instruments, and exoplanets are characterized with increasing precision. There is a class of particularly interesting exoplanets that reside in the habitable zone, which is defined as the area around a star where the planet is capable of supporting liquid water on its surface. Planetary systems around M dwarfs are considered to be prime candidates to search for life beyond the Solar System. Such planets are likely to be tidally locked and have close-in habitable zones. Theoretical calculations also suggest that close-in exoplanets are more likely to have weaker planetary magnetic fields, especially in the case of super-Earths. Such exoplanets are subjected to a high flux of galactic cosmic rays (GCRs) due to their weak magnetic moments. GCRs are energetic particles of astrophysical origin that strike the planetary atmosphere and produce secondary particles, including muons, which are highly penetrating. Some of these particles reach the planetary surface and contribute to the radiation dose. Along with the magnetic field, another factor governing the radiation dose is the depth of the planetary atmosphere. The higher the depth of the planetary atmosphere, the lower the flux of secondary particles will be on the surface. If the secondary particles are energetic enough, and their flux is sufficiently high, the radiation from muons can also impact the subsurface regions, such as in the case of Mars. If the radiation dose is too high, the chances of sustaining a long-term biosphere on the planet are very low. We have examined the dependence of the GCR-induced radiation dose on the strength of the planetary magnetic field and its atmospheric depth, and found that the latter is the decisive factor for the protection of a planetary biosphere. PMID:24143867

Atri, Dimitra; Hariharan, B; Grießmeier, Jean-Mathias

2013-10-01

310

Frequency-comb-induced radiative force on cold rubidium atoms  

NASA Astrophysics Data System (ADS)

We experimentally investigate the radiative force and laser-induced fluorescence (LIF) in cold rubidium atoms induced by pulse-train (frequency-comb) excitation. Three configurations are studied: (i) single-pulse-train excitation, (ii) two in-phase counterpropagating pulse trains, and (iii) two out-of-phase counterpropagating pulse trains. In all configurations, measured LIF is in agreement with calculations based on the optical Bloch equations. The observed forces in the first two configurations are in qualitative agreement with the model(s) used for calculating mechanical action of a pulse train on atoms; however, this is not the case for the third configuration. Possible resolution of the discrepancy is discussed.

Kregar, G.; Šanti?, N.; Aumiler, D.; Buljan, H.; Ban, T.

2014-05-01

311

Theoretical simulations of the radiation-induced defect processes in insulating materials  

NASA Astrophysics Data System (ADS)

The results of two basic kinds of computer simulations of radiation-induced processes in insulating materials, one based on quantum-mechanical and pair-potential (atomistic) approaches, and the other a phenomenological theory of diffusion-controlled reactions, are presented. It is shown that, by combining different techniques (atom-atom potentials and semi-empirical quantum chemical methods) the optimized geometry and the electronic structure of a family of hole centres in crystalline corundum (?-Al 2O 3) could be found. Their energetics are analyzed; V 2-, V -V -Mg hole centres all have a common basic element, namely the diatomic molecule O 23-, which is responsible for their similar absorption energies. Our calculations provide evidence for the existence of a small-radius two-centre polaron (self-trapped hole, or STH) with an optical absorption energy of around 2.9 eV. The strong covalent bonding of the two O atoms sharing a hole makes this centre analogous to the V K centre in alkali halides. The calculated activation energy for the STH hops (? 0.9 eV) between different O triangles is close to the experimental.

Kotomin, E. A.; Jacobs, P. W. M.

1994-06-01

312

Radiation-induced luminescence in magnesium aluminate spinel crystals and ceramics  

NASA Astrophysics Data System (ADS)

Radioluminescence (RL) and thermoluminescence (TL) in spinel crystals and ceramics were investigated to elucidate the radiation-induced electronic processes in single crystals grown by Verneuil and Czochralski methods as well as transparent and translucent ceramics. Both RL and TL spectra demonstrate a UV-band related to electron-hole recombination luminescence at intrinsic defects; green and red luminescence are identified with emission of Mn 2+- and Cr 3+-ions, respectively. The kinetics of growth of different RL luminescence bands depending on dose at the prolonged X-irradiation shows the competitive character of charge and energy transfer between defects and impurity ions. The dependence of RL intensity on the temperature of the sample was measured in the range of 300-750 K and compared with TL for different emission bands. The variety of maxima in the temperature dependence of RL and in the glow curves of TL measured for different luminescence bands in spinels of different origins and crystalline forms is used to show that charge carrier traps and luminescence centers are not isolated defects but are complexes of defects and impurities. The formation, structure and properties of these complexes depend on the processing conditions.

Gritsyna, V. T.; Kazarinov, Yu. G.; Kobyakov, V. A.; Reimanis, I. E.

2006-09-01

313

Field-induced weak ferromagnetism in single-crystalline DyFe0.8Mn0.2O3  

NASA Astrophysics Data System (ADS)

Single-crystalline DyFe1- x Mn x O3 perovskites with the nominal Mn contents of x = 0.2, 0.5, and 0.7 were grown successfully. The solid solutions have an orthorhombic structure with space group Pbnm. Magnetic susceptibilities at different crystallographic axes show a large magnetic anisotropy, primarily originating from the large spin-orbit coupling of the Dy moment. For DyFe0.8Mn0.2O3, a room-temperature weak ferromagnetism is confirmed along the c-axis. A spin reorientation transition occurs at T SR ? 225 K, below which the canted weak ferromagnetic moment disappears. The application of a high magnetic field (µ0H ? 6 T) along the c-axis at T = 200 K unveils a hidden field-induced weak ferromagnetism, which probably has the same spin configuration as that above T SR ? 225 K.

Cho, Kwanghee; Park, Soonyong

2013-07-01

314

Swelling and radiation-induced segregation in austentic alloys  

NASA Astrophysics Data System (ADS)

To elucidate the relationship between radiation-induced segregation and swelling in austenitic stainless steels, a series of alloys were irradiated with 3.2 MeV protons to doses of 0.5 and 1.0 dpa at 400 °C. Three alloy series were irradiated, the first to examine the effect of bulk nickel in Fe-16-18Cr- xNi, the second to determine the effect of Mo and P in an Fe-16Cr-13Ni base alloy, and the third to examine the effect of oversized solute Zr addition to an Fe-18Cr-0.5Ni alloy. The addition of nickel in Fe-16-18Cr- xNi caused a significant decrease in swelling and increase in segregation. The addition of Mo+P to Fe-16Cr-13Ni eliminated swelling and reduced segregation. The addition of Zr to Fe-18Cr-9.5Ni decreased swelling and altered the segregation. Comparison of swelling with changes in lattice parameter and shear modulus caused by the segregation showed that swelling correlates well with the decreases in lattice parameter caused by radiation-induced segregation. Those alloys whose segregation decreased the lattice parameter the greatest showed the lowest swelling. These results are consistent with theoretical predictions made by Wolfer.

Allen, T. R.; Cole, J. I.; Gan, J.; Was, G. S.; Dropek, R.; Kenik, E. A.

2005-06-01

315

Radiation-induced chondrosarcoma of the maxilla 7-year after combined chemoradiation for tonsillar lymphoma.  

PubMed

Radiation-induced sarcoma is a rare complication of radiation therapy. We report a case of radiation-induced chondrosarcoma of the maxilla. An 80-year-old Persian woman developed radiation-induced chondrosarcoma of the left maxilla 7 years after combined chemotherapy and external beam radiation therapy for the Ann Arbor stage IE malignant lymphoma of the right tonsil. She underwent suboptimal tumour resection and died due to extensive locoregional disease 8 months later. An English language literature search of Medline using the terms chondrosarcoma, radiation-induced sarcoma and maxilla revealed only one earlier reported case. We describe the clinical and pathological features of this case and review the literature on radiation-induced sarcomas. PMID:15377806

Mohammadianpanah, M; Gramizadeh, B; Omidvari, Sh; Mosalaei, A

2004-01-01

316

Use of Photostimulated Luminescence for Studying the Characteristics of Radiation-Induced Electron Centers.  

National Technical Information Service (NTIS)

The kinetics of recombination processes in a solid body depends in great measure on the probability of repeated localizations (RL) of the charge carriers in pre-radiation and radiation induced microdefects. Repeated localizations can determine in a broad ...

B. I. Rogalev, I. A. Parfianovich, P. N. Yarovoii, V. G. Krongauz

1973-01-01

317

Mechanisms of Radiation-Induced Bone Loss and Effect on Prostate Cancer Bone Metastases.  

National Technical Information Service (NTIS)

Patients with tumors in the pelvic region frequently receive radiation therapy, and as a result, bystander bone may experience adverse effects. Earlier reports demonstrated that radiation-induced bone loss occurs via increased osteoclast activation in a m...

H. S. Kim

2012-01-01

318

Modelling radiation-induced bystander effect and cellular communication.  

PubMed

In the last 10 years evidence has accumulated on the so-called radiation-induced 'non-targeted effects' and in particular on bystander effects, consisting of damage induction in non-irradiated cells most likely following the release of soluble factors by the irradiated ones. These phenomena were observed for different biological endpoints, both lethal and non-lethal for the cell. Although the underlying mechanisms are largely unknown, it is now widely recognised that two types of cellular communication (i.e. via gap junctions and/or release of molecular messengers into the extracellular environment) play a pivotal role. Furthermore, the effects can be significantly modulated by parameters such as cell type and cell-cycle stage, cell density, time after irradiation etc. Theoretical models and simulation codes can be of help to improve our knowledge of the mechanisms, as well as to investigate the possible role of these effects in determining deviations from the linear relationship between dose and risk which is generally applied in radiation protection. In this paper three models, including an approach under development at the University of Pavia, will be presented in detail. The focus will be on the various adopted assumptions, together with their implications in terms of non-targeted radiobiological damage and, more generally, low-dose radiation risk. Comparisons with experimental data will also be discussed. PMID:17142819

Ballarini, F; Alloni, D; Facoetti, A; Mairani, A; Nano, R; Ottolenghi, A

2006-01-01

319

Polyamines protect against radiation-induced oxidative stress.  

PubMed

Astronauts and cosmonauts are exposed to a wide variety of different hazards while in space that include radiation, which presents one of the most critical barriers to long-term missions. A major deleterious effect directly associated with ionizing radiation is the production of reactive oxygen species (ROS) such as peroxides and hydroxyl radicals. The free radicals generated by ultraviolet (UV) or ionizing radiation can attack cellular lipids, proteins and DNA. Endogenous free radical scavengers such as glutathione and the polyamines (e.g, spermidine and spermine) can inhibit the action of ROS. In particular, heme oxygenase-1 (HO-1), the enzyme involved in heme protein metabolism, can provide antioxidant protection through the production of the antioxidant bilirubin. Furthermore, polyamines have been shown to indirectly increase HO-1 content and antioxidant protection. The beta2-adrenoceptor agonist clenbuterol has been shown to stimulate polyamine synthesis and by extension, might provide a margin of antioxidant protection through increasing HO-1 content. However, it is unclear whether the polyamines are acting as a tertiary messengers for antioxidant protection in the be beta2-adrenoceptor signal transduction pathway. The purpose of this study was to study the role of the polyamine pathway in attenuating free radical-induced damage. PMID:16044631

von Deutsch, Albert W; Mitchell, Clarence D; Williams, Chris E; Dutt, Kamla; Silvestrov, Natalia A; Klement, Brenda J; Abukhalaf, Imad K; von Deutsch, Daniel A

2005-06-01

320

Radiation induces epithelial-mesenchymal transition in colorectal cancer cells.  

PubMed

Radiotherapy remains a major approach to adjuvant therapy for patients with advanced rectal cancer. Nevertheless, the effects of radiation on malignant processes have yet to be clarified. The aim of this study was to assess the biological effects of radiation on colorectal cancer (CRC) cells with special reference to epithelial-mesenchymal transition (EMT), a key developmental program often activated during cancer invasion and metastasis. We investigated the effect of radiation on two colorectal cancer cell lines, CaR1 and DLD1, assessing cell morphology, motility, migration and invasive ability. Expression of molecules associated with EMT was determined using RT-PCR, Western blotting, and immunofluorescence staining in control and irradiated cells. We also used real-time RT-PCR to examine the expression of molecules associated with EMT before and after chemoradiotherapy. Thus, we studied 26 rectal cancer patients who received preoperative chemoradiotherapy followed by radical surgery. In addition, we examined the relationship between disease recurrence and the expression of a number of proteins. Irradiation caused CRC cells to undergo phenotypic changes characteristic of EMT: spindle-cell shape, loss of polarity, intercellular separation and pseudopodia formation. Irradiation enhanced cell migration and invasiveness. In irradiated CRC cells, molecular changes consistent with EMT were observed. In clinical samples, we observed molecular changes consistent with EMT, and those changes were significantly enhanced in patients with recurring disease. These results indicate that irradiation induces an alteration to a malignant phenotype consistent with EMT in colorectal cancer cells. PMID:21971767

Kawamoto, Aya; Yokoe, Takeshi; Tanaka, Koji; Saigusa, Susumu; Toiyama, Yuji; Yasuda, Hiromi; Inoue, Yasuhiro; Miki, Chikao; Kusunoki, Masato

2012-01-01

321

Robust Feedback Control of Flow Induced Structural Radiation of Sound  

NASA Technical Reports Server (NTRS)

A significant component of the interior noise of aircraft and automobiles is a result of turbulent boundary layer excitation of the vehicular structure. In this work, active robust feedback control of the noise due to this non-predictable excitation is investigated. Both an analytical model and experimental investigations are used to determine the characteristics of the flow induced structural sound radiation problem. The problem is shown to be broadband in nature with large system uncertainties associated with the various operating conditions. Furthermore the delay associated with sound propagation is shown to restrict the use of microphone feedback. The state of the art control methodologies, IL synthesis and adaptive feedback control, are evaluated and shown to have limited success for solving this problem. A robust frequency domain controller design methodology is developed for the problem of sound radiated from turbulent flow driven plates. The control design methodology uses frequency domain sequential loop shaping techniques. System uncertainty, sound pressure level reduction performance, and actuator constraints are included in the design process. Using this design method, phase lag was added using non-minimum phase zeros such that the beneficial plant dynamics could be used. This general control approach has application to lightly damped vibration and sound radiation problems where there are high bandwidth control objectives requiring a low controller DC gain and controller order.

Heatwole, Craig M.; Bernhard, Robert J.; Franchek, Matthew A.

1997-01-01

322

Molecular Mechanisms and Treatment of Radiation-Induced Lung Fibrosis  

PubMed Central

Radiation-induced lung fibrosis (RILF) is a severe side effect of radiotherapy in lung cancer patients that presents as a progressive pulmonary injury combined with chronic inflammation and exaggerated organ repair. RILF is a major barrier to improving the cure rate and well-being of lung cancer patients because it limits the radiation dose that is required to effectively kill tumor cells and diminishes normal lung function. Although the exact mechanism is unclear, accumulating evidence suggests that various cells, cytokines and regulatory molecules are involved in the tissue reorganization and immune response modulation that occur in RILF. In this review, we will summarize the general symptoms, diagnostics, and current understanding of the cells and molecular factors that are linked to the signaling networks implicated in RILF. Potential approaches for the treatment of RILF will also be discussed. Elucidating the key molecular mediators that initiate and control the extent of RILF in response to therapeutic radiation may reveal additional targets for RILF treatment to significantly improve the efficacy of radiotherapy for lung cancer patients.

Ding, Nian-Hua; Li, Jian Jian; Sun, Lun-Quan

2013-01-01

323

Proton-induced radiation damage in germanium detectors  

NASA Technical Reports Server (NTRS)

High-purity germanium (HPGe) detectors will be used in future space missions for gamma-ray measurements and will be subject to interactions with energetic particles. To simulate this process, several large-volume n-type HPGe detectors were incrementally exposed to a particle fluence of up to 10 to the 8th protons/sq cm (proton energy: 1.5 GeV) at different operating temperatures (90 to 120 K) to induce radiation damage. Basic scientific and engineering data on detector performance were collected. During the incremental irradiation, the peak shape produced by the detectors showed a significant change from a Gaussian shape to a broad complex structure. After the irradiation, all detectors were thoroughly characterized by measuring many parameters. To remove the accumulated radiation damage, the detectors were stepwise-annealed at temperatures below 110 C, while kept in their specially designed cryostats. This study shows that n-type HPGe detectors can be used in charged-particle environments as high-energy resolution devices until a certain level of radiation damage is accumulated and that the damage can be removed at moderate annealing temperatures and the detector returned to operating condition.

Brueckner, J.; Koerfer, M.; Waenke, H.; Schroeder, A. N. F.; Filges, D.; Dragovitsch, P.; Englert, P. A. J.; Starr, R.; Trombka, J. I.

1991-01-01

324

Radiation-induced defects in clay minerals: A review  

NASA Astrophysics Data System (ADS)

Extensive information has been collected on radiation effects on clay minerals over the last 35 years, providing a wealth of information on environmental and geological processes. The fields of applications include the reconstruction of past radioelement migrations, the dating of clay minerals or the evolution of the physico-chemical properties under irradiation. The investigation of several clay minerals, namely kaolinite, dickite, montmorillonite, illite and sudoite, by Electron Paramagnetic Resonance Spectroscopy has shown the presence of defects produced by natural or artificial radiations. These defects consist mostly of electron holes located on oxygen atoms of the structure. The various radiation-induced defects are differentiated through their nature and their thermal stability. Most of them are associated with a ? orbital on a Si-O bond. The most abundant defect in clay minerals is oriented perpendicular to the silicate layer. Thermal annealing indicates this defect in kaolinite (A-center) to be stable over geological periods at ambient temperature. Besides, electron or heavy ion irradiation easily leads to an amorphization in smectites, depending on the type of interlayer cation. The amorphization dose exhibits a bell-shaped variation as a function of temperature, with a decreasing part that indicates the influence of thermal dehydroxylation. Two main applications of the knowledge of radiation-induced defects in clay minerals are derived: (i) The use of defects as tracers of past radioactivity. In geological systems where the age of the clay can be constrained, ancient migrations of radioelements can be reconstructed in natural analogues of high level nuclear waste repositories. When the dose rate may be assumed constant over time, the paleodose is used to date clay populations, an approach applied to fault gouges or laterites of the Amazon basin. (ii) The influence of irradiation over physico-chemical properties of clay minerals. An environmental application concerns the performance assessment of the engineered barrier of nuclear waste disposals. In case of a leakage of transuranic elements from the radioactive waste form, alpha recoil nuclei can amorphize smectite after periods of the order of 1000 years according to a worst case scenario, whereas amorphization from ionizing radiation is unlikely. As amorphization greatly enhances the dissolution kinetics of smectite, the sensitivity of the smectites must be taken into account in the prediction of the long term behavior of engineered barriers.

Allard, Th.; Balan, E.; Calas, G.; Fourdrin, C.; Morichon, E.; Sorieul, S.

2012-04-01

325

Risk estimates for radiation-induced cancer and radiation protection standards  

SciTech Connect

At low doses, the primary biological effects of concern are stochastic in nature, i.e., they are more probable at higher doses, but their severity is independent of the dose. In the last decade, a new epidemiological information on radiation-induced cancer in humans has become available. In the Japanese survivors three new cycles of data (11 yr of experience) have accumulated, and a revised dosimetry system (DS86) has been introduced. UNSCEAR (United Nations Scientific Committee on the Effects of Atomic Radiation) reevaluated the risk of cancer from all human sources, which include other human populations such as those treated for ankylosing spondylitis and for cancer of the cervix. UNSCEAR has also evaluated the cancer risk for each of nine organs. For radiation protection purposes (low doses and dose rates, adult populations mainly), nominal values of risk since the 1977-80 period have been {approximately}1%/Sv. This value will need to be increased in the light of the new estimates. Also, risk estimates for various tissues must be reconsidered, and weighting factors used by International Commission on Radiological Protection need to be reexamined. Recommendations on occupational and public dose limits must also be reconsidered. The National Council on Radiation Protection and Measurements is in a comparatively good position with a recently produced set of recommendations that had higher cancer risk estimates in mind.

Sinclair, W.K. (National Council on Radiation Protection and Measurements, Bethesda, MD (USA))

1989-11-01

326

Radiation-Induced Lymphocyte Apoptosis to Predict Radiation Therapy Late Toxicity in Prostate Cancer Patients  

SciTech Connect

Purpose: To examine a potential correlation between the in vitro apoptotic response of lymphocytes to radiation and the risk of developing late gastrointestinal (GI)/genitourinary (GU) toxicity from radiotherapy for prostate cancer. Methods and Materials: Prostate cancer patients formerly enrolled in a randomized study were tested for radiosensitivity by using a radiation-induced lymphocyte apoptosis assay. Apoptosis was measured using flow cytometry-based Annexin-FITC/7AAD and DiOC{sub 6}/7AAD assays in subpopulations of lymphocytes (total lymphocytes, CD4+, CD8+ and CD4-/CD8-) after exposure to an in vitro dose of 0, 2, 4, or 8 Gy. Results: Patients with late toxicity after radiotherapy showed lower lymphocyte apoptotic responses to 8 Gy than patients who had not developed late toxicity (p = 0.01). All patients with late toxicity had apoptosis levels that were at or below the group mean. The negative predictive value in both apoptosis assays ranged from 95% to 100%, with sensitivity values of 83% to 100%. Apoptosis at lower dose points and in lymphocyte subpopulations had a weaker correlation with the occurrence of late toxicity. Conclusions: Lymphocyte apoptosis after 8 Gy of radiation has the potential to predict which patients will be spared late toxicity after radiation therapy. Further research should be performed to identify the specific subset of lymphocytes that correlates with late toxicity, followed by a corresponding prospective study.

Schnarr, Kara [Department of Medicine, St. George's University, Grenada, WI (Grenada); Boreham, Douglas [Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, ON (Canada); Sathya, Jinka [Department of Radiation Oncology, University of Manitoba, Winnipeg, MB (Canada); Julian, Jim [Department of Oncology, McMaster University, Hamilton, Ontario (Canada); Dayes, Ian S. [Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, ON (Canada); Department of Oncology, McMaster University, Hamilton, Ontario (Canada)], E-mail: Ian.Dayes@jcc.hhsc.ca

2009-08-01

327

Image-based modeling of radiation-induced foci  

NASA Astrophysics Data System (ADS)

Several proteins involved in the response to DNA double strand breaks (DSB) form microscopically visible nuclear domains, or foci, after exposure to ionizing radiation. Radiation-induced foci (RIF) are believed to be located where DNA damage occurs. To test this assumption, we used Monte Carlo simulations to predict the spatial distribution of DSB in human nuclei exposed to high or low-LET radiation. We then compared these predictions to the distribution patterns of three DNA damage sensing proteins, i.e. 53BP1, phosphorylated ATM and ?H2AX in human mammary epithelial. The probability to induce DSB can be derived from DNA fragment data measured experimentally by pulsed-field gel electrophoresis. We first used this probability in Monte Carlo simulations to predict DSB locations in synthetic nuclei geometrically described by a complete set of human chromosomes, taking into account microscope optics from real experiments. Simulations showed a very good agreement for high-LET, predicting 0.7 foci/µm along the path of a 1 GeV/amu Fe particle against measurement of 0.69 to 0.82 foci/µm for various RIF 5 min following exposure (LET 150 keV/µm). On the other hand, discrepancies were shown in foci frequency for low-LET, with measurements 20One drawback using a theoretical model for the nucleus is that it assumes a simplistic and static pattern for DNA densities. However DNA damage pattern is highly correlated to DNA density pattern (i.e. the more DNA, the more likely to have a break). Therefore, we generalized our Monte Carlo approach to real microscope images, assuming pixel intensity of DAPI in the nucleus was directly proportional to the amount of DNA in that pixel. With such approach we could predict DNA damage pattern in real images on a per nucleus basis. Since energy is randomly deposited along high-LET particle paths, RIF along these paths should also be randomly distributed. As expected, simulations produced DNA-weighted random (Poisson) distributions. In contrast, the distributions of RIF obtained as early as 5 min after exposure to high LET (1 GeV/amu Fe) were non-random. This deviation from the expected DNA-weighted random pattern was further characterized by "relative DNA image measurements". This novel imaging approach showed that RIF were located preferentially at the interface between high and low DNA density regions, and were more frequent than predicted in regions with lower DNA density. The same preferential nuclear location was also measured for RIF induced by 1 Gy of low-LET radiation. This deviation from random behavior was evident only 5 min after irradiation for phosphorylated ATM RIF, while ?H2AX and 53BP1 RIF showed pronounced deviations up to 30 min after exposure. These data suggest that RIF within a few minutes following exposure to radiation cluster into open regions of the nucleus (i.e. euchromatin). It is possible that DNA lesions are collected in these nuclear sub-domains for more efficient repair. If so, this would imply that DSB are actively transported within the nucleus, a phenomenon that has not yet been considered in modeling DNA misrepair following exposure to radiation. These results are thus critical for more accurate risk models of radiation and we are actively working on characterizing further RIF movement in human nuclei using live cell imaging.

Costes, Sylvain; Cucinotta, Francis A.; Ponomarev, Artem; Barcellos-Hoff, Mary Helen; Chen, James; Chou, William; Gascard, Philippe

328

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

SciTech Connect

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.

Kandasamy, S.B.; Hunt, W.A. (Armed Forces Radiobiology Research Institute, Bethesda, MD (USA))

1990-01-01

329

FEM numerical analysis of excimer laser induced modification in alternating multi-layers of amorphous and nano-crystalline silicon films  

NASA Astrophysics Data System (ADS)

UV excimer laser annealing (UV-ELA) is an alternative annealing process that, during the last few years, has gained enormous importance for the CMOS nano-electronic technologies, with the ability to provide films and alloys with electrical and optical properties to fit the desired device performance. The UV-ELA of amorphous (a-) and/or doped nano-crystalline (nc-) silicon films is based on the rapid (nanoseconds) formation of temperature profiles caused by laser radiation that is absorbed in the material and lead to crystallisation, diffusion in solid or even in liquid phase. To achieve the desired temperature profiles and to optimize the parameters involved in the processing of hydrogenated nanocrystalline silicon (nc-Si:H) films with the UV-ELA, a numerical analysis by finite element method (FEM) of a multilayer structure has been performed. The multilayer structures, consisting of thin alternating a-Si:H(10 nm) and n-doped nc-Si:H(60 nm) layers, deposited on a glass substrate, has also been experimentally analyzed. Temperature profiles caused by 193 nm radiation with 25 ns pulse length and energy densities ranging from 50 mJ/cm2 to 400 mJ/cm2 have been calculated. Numerical results allowed us to estimate the dehydrogenation process of the different layers and the diffusion of phosphorous (P) in Si layers as well as their structural modifications as a function of the applied laser energy density. Numerical results are compared with exhaustive characterization of the experimental results.

Conde, J. C.; Martín, E.; Stefanov, S.; Alpuim, P.; Chiussi, S.

2012-09-01

330

An Amino Acid Mixture Mitigates Radiation-induced Gastrointestinal Toxicity.  

PubMed

Electrolyte and nutrient absorption occur in villous epithelial cells. Radiation often results in reduced electrolyte and nutrient absorption, which leads to gastrointestinal toxicity. Therefore, the authors studied: (1) radiation-induced changes in glucose and amino acid absorption across ileal tissues and (2) the effect of amino acid mixtures on absorptive capacity. NIH Swiss mice were irradiated (0, 1, 3, 5, or 7 Gy) using a Cs source at 0.9 Gy min. Transepithelial short circuit current (Isc), dilution potential, and isotope flux determinations were made in Ussing chamber studies and correlated to plasma endotoxin and IL-1? levels. Amino acids that increased electrolyte absorption and improved mucosal barrier functions were used to create a mitigating amino acid mixture (MAAM). The MAAM was given to mice via gastric gavage; thereafter, body weight and survival were recorded. A significant decrease in basal and glucose-stimulated sodium absorption occurred after 0, 1, 3, 5, and 7 Gy irradiation. Ussing chamber studies showed that paracellular permeability increased following irradiation and that the addition of glucose resulted in a further increase in permeability. Following irradiation, certain amino acids manifested decreased absorption, whereas others were associated with increased absorption. Lysine, aspartic acid, glycine, isoleucine, threonine, tyrosine, valine, tryptophan, and serine decreased plasma endotoxins were selected for the MAAM. Mice treated with the MAAM showed increased electrolyte absorption and decreased paracellular permeability, IL-1? levels, and plasma endotoxin levels. Mice treated with MAAM also had increased weight gain and better survival following irradiation. The MAAM has immediate potential for use in mitigating radiation-induced acute gastrointestinal syndrome. PMID:24776907

Yin, Liangjie; Vijaygopal, Pooja; Menon, Rejeesh; Vaught, Lauren A; Zhang, Mei; Zhang, Lurong; Okunieff, Paul; Vidyasagar, Sadasivan

2014-06-01

331

Inflammatory-type responses after exposure to ionizing radiation in vivo: a mechanism for radiation-induced bystander effects?  

PubMed

Haemopoietic tissues exposed to ionizing radiation are shown to exhibit increased macrophage activation, defined by ultrastructural characteristics and increased lysosomal and nitric oxide synthase enzyme activities. Macrophage activation post-irradiation was also associated with enhanced respiratory burst activities and an unexpected neutrophil infiltration. Examination of p53-null mice demonstrated that macrophage activation and neutrophil infiltration were not direct effects of irradiation, but were a consequence of the recognition and clearance of radiation-induced apoptotic cells. Increased phagocytic cell activity was maintained after apoptotic bodies had been removed. These findings demonstrate that, contrary to expectation, recognition and clearance of apoptotic cells after exposure to radiation produces both a persistent macrophage activation and an inflammatory-type response. We also demonstrate a complexity of macrophage activation following radiation that is genotype dependent, indicating that the in vivo macrophage responses to radiation damage are genetically modified processes. These short-term responses of macrophages to radiation-induced apoptosis and their genetic modification are likely to be important determinants of the longer-term consequences of radiation exposure. Furthermore, in addition to any effects attributable to immediate radiation-induced damage, our findings provide a mechanism for the production of damage via a 'bystander' effect which may contribute to radiation-induced genomic instability and leukaemogenesis. PMID:11704832

Lorimore, S A; Coates, P J; Scobie, G E; Milne, G; Wright, E G

2001-10-25

332

Interaction of alpha radiation with thermally-induced defects in silicon  

SciTech Connect

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{sub c}-0.48 eV and E{sub 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.

Ali, Akbar [Advance Materials Physics Lab. Department of Physics, Quaid-i-Azam University, Islamabad (Pakistan)], E-mail: aarandhawa@yahoo.com; Majid, Abdul [Advance Materials Physics Lab. Department of Physics, Quaid-i-Azam University, Islamabad (Pakistan)], E-mail: abdulmajid40@yahoo.com

2008-01-15

333

Dosimetric Analysis of Radiation-induced Gastric Bleeding  

SciTech Connect

Purpose: Radiation-induced gastric bleeding has been poorly understood. In this study, we described dosimetric predictors for gastric bleeding after fractionated radiation therapy. Methods and Materials: The records of 139 sequential patients treated with 3-dimensional conformal radiation therapy (3D-CRT) for intrahepatic malignancies were reviewed. Median follow-up was 7.4 months. The parameters of a Lyman normal tissue complication probability (NTCP) model for the occurrence of {>=}grade 3 gastric bleed, adjusted for cirrhosis, were fitted to the data. The principle of maximum likelihood was used to estimate parameters for NTCP models. Results: Sixteen of 116 evaluable patients (14%) developed gastric bleeds at a median time of 4.0 months (mean, 6.5 months; range, 2.1-28.3 months) following completion of RT. The median and mean maximum doses to the stomach were 61 and 63 Gy (range, 46-86 Gy), respectively, after biocorrection of each part of the 3D dose distributions to equivalent 2-Gy daily fractions. The Lyman NTCP model with parameters adjusted for cirrhosis predicted gastric bleed. Best-fit Lyman NTCP model parameters were n=0.10 and m=0.21 and with TD{sub 50} (normal) = 56 Gy and TD{sub 50} (cirrhosis) = 22 Gy. The low n value is consistent with the importance of maximum dose; a lower TD{sub 50} value for the cirrhosis patients points out their greater sensitivity. Conclusions: This study demonstrates that the Lyman NTCP model has utility for predicting gastric bleeding and that the presence of cirrhosis greatly increases this risk. These findings should facilitate the design of future clinical trials involving high-dose upper abdominal radiation.

Feng, Mary, E-mail: maryfeng@umich.edu [Department of Radiation Oncology, University of Michigan School of Medicine, Ann Arbor, Michigan (United States)] [Department of Radiation Oncology, University of Michigan School of Medicine, Ann Arbor, Michigan (United States); Normolle, Daniel [Department of Biostatistics, University of Pittsburgh, Pittsburgh, Pennsylvania (United States)] [Department of Biostatistics, University of Pittsburgh, Pittsburgh, Pennsylvania (United States); Pan, Charlie C. [Department of Radiation Oncology, University of Michigan School of Medicine, Ann Arbor, Michigan (United States)] [Department of Radiation Oncology, University of Michigan School of Medicine, Ann Arbor, Michigan (United States); Dawson, Laura A. [Department of Radiation Oncology, Princess Margaret Hospital, University of Toronto, Toronto, Ontario (Canada)] [Department of Radiation Oncology, Princess Margaret Hospital, University of Toronto, Toronto, Ontario (Canada); Amarnath, Sudha [Department of Radiation Oncology, University of Michigan School of Medicine, Ann Arbor, Michigan (United States)] [Department of Radiation Oncology, University of Michigan School of Medicine, Ann Arbor, Michigan (United States); Ensminger, William D. [Department of Internal Medicine, Division of Hematology Oncology, University of Michigan School of Medicine, Ann Arbor, Michigan (United States)] [Department of Internal Medicine, Division of Hematology Oncology, University of Michigan School of Medicine, Ann Arbor, Michigan (United States); Lawrence, Theodore S.; Ten Haken, Randall K. [Department of Radiation Oncology, University of Michigan School of Medicine, Ann Arbor, Michigan (United States)] [Department of Radiation Oncology, University of Michigan School of Medicine, Ann Arbor, Michigan (United States)

2012-09-01

334

Pressure Induced Phase Transitions in Vacancy Doped Nano-Crystalline Manganites Through High-Pressure MÖSSBAUER Spectroscopy  

NASA Astrophysics Data System (ADS)

Vacancy-doping at A and B sites in nanocrystalline perovskite Manganites ABO3 (A = RE, and B = Mn) change their electrical and magnetic behaviour as compared to the stoichiometric counterpart. We report here the effect of pressure up to 10 GPa on the vacancy-doped nanocrystalline manganites synthesized by sol-gel nitrate technique. The Mössbauer measurements on nano-crystalline La-deficient sample La0.9Mn0.8Fe0.2O3.15 at ambient condition show distribution of Fe3+ ions at two different environments. Interesting features observed with variation in pressure on the sample are-an isostructural high spin Fe3+ to low spin Fe3+ transition (at 2.1 GPa), reversal to high spin again (at 2.8 GPa) and an orthorhombic to monoclinic structural transition (at 4.9 GPa). However nanocrystalline Mn-deficient sample La0.86Sr0.14Mn0.80Fe.016O2.91 behaves differently. Unlike La-deficient sample, it retains isostructural high spin Fe3+ configuration up to 4.9 GPa. The structural transition from orthorhombic to monoclinic seems to be incomplete even at 6.3 GPa. Decrease in isomer shift of one of the sites indicates strong covalent interaction persisting between Mn and Fe ions. Low temperature Mössbauer measurements at 80 K show appearance of magnetic sextet in Mn deficient sample while La-deficient sample remains paramagnetic.

Chandra, Usha

2009-12-01

335

[New results on the linearity of the dose-response relationship of radiation-induced mutation].  

PubMed

Mutations induced by ionizing radiation in germ cells may affect future generations; mutations induced in somatic cells may damage the irradiated persons themselves, because radiation carcinogenesis is assumed to result from genetic damage induced in somatic cells. Since we are exposed mainly to low doses of ionizing radiation, both from natural and artificial sources, especially the dose dependence of radiation-induced mutations in the low-dose range is of interest. A review of recent studies on the induction of mutations by X-rays in human cells (in vitro) favors the hypothesis that in the low-dose range the dose dependence is linear, without a "threshold." PMID:3065646

Traut, H

1988-08-01

336

Motion-induced radiation from electrons moving in Maxwell's fish-eye.  

PubMed

In ?erenkov radiation and transition radiation, evanescent wave from motion of charged particles transfers into radiation coherently. However, such dissipative motion-induced radiations require particles to move faster than light in medium or to encounter velocity transition to pump energy. Inspired by a method to detect cloak by observing radiation of a fast-moving electron bunch going through it by Zhang et al., we study the generation of electron-induced radiation from electrons' interaction with Maxwell's fish-eye sphere. Our calculation shows that the radiation is due to a combination of ?erenkov radiation and transition radiation, which may pave the way to investigate new schemes of transferring evanescent wave to radiation. PMID:24166002

Liu, Yangjie; Ang, L K

2013-01-01

337

Motion-induced radiation from electrons moving in Maxwell's fish-eye  

NASA Astrophysics Data System (ADS)

In ?erenkov radiation and transition radiation, evanescent wave from motion of charged particles transfers into radiation coherently. However, such dissipative motion-induced radiations require particles to move faster than light in medium or to encounter velocity transition to pump energy. Inspired by a method to detect cloak by observing radiation of a fast-moving electron bunch going through it by Zhang et al., we study the generation of electron-induced radiation from electrons' interaction with Maxwell's fish-eye sphere. Our calculation shows that the radiation is due to a combination of ?erenkov radiation and transition radiation, which may pave the way to investigate new schemes of transferring evanescent wave to radiation.

Liu, Yangjie; Ang, L. K.

2013-10-01

338

Pressure induced phase transitions in Vacancy-doped nano-crystalline manganites through High-pressure Mössbauer spectroscopy  

NASA Astrophysics Data System (ADS)

Nanocrystalline perovskite Manganites ABO3 (A=RE, and B= Mn) are interesting materials due to their colossal magneto resistive behaviour. The effect of vacancy-doping at A and B sites show changes in their behaviour as compared to the stoichiometric counterpart. We report here the effect of pressure on the vacancy-doped nanocrystalline manganites synthesized by sol-gel nitrate technique up to 10 GPa. The Mössbauer measurements on nano-crystalline La-deficient sample La0.9Mn0.8Fe0.2O3.15 at ambient condition show distribution of Fe^3+ ions at two different environments. Interesting features are observed with variation in pressure on the sample -- an isostructural high spin Fe^3+ to low spin Fe^3+ transition (at 2.1 GPa), reversal to high spin again (at 2.8 GPa) and an orthorhombic to monoclinic structural transition (at 4.9 GPa). However nanocrystalline Mn-deficient sample La0.8Sr0.2Mn0.8Fe.16O2.95 behaves differently. Unlike La-deficient sample, it retains isostructural high spin Fe^3+ configuration up to 4.2 GPa. The structural transition from orthorhombic to monoclinic seems to be still incomplete even at 6.3 GPa. Decrease in isomer shift of one of the site indicates strong covalent interaction between Mn and Fe ions. Low temperature Mössbauer measurements at 80 K show appearance of magnetic sextet in Mn deficient sample while La-deficient remains paramagnetic.

Chandra, Usha

2009-06-01

339

Role of Neurotensin in Radiation-Induced Hypothermia in Rats. (Reannouncement with New Availability Information).  

National Technical Information Service (NTIS)

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 stab...

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

1991-01-01

340

Radiation from Large Space Structures in Low Earth Orbit with Induced Alternating Currents,  

National Technical Information Service (NTIS)

Large conducting space structures in low Earth orbit will have a nonnegligible induced potential across their structures. The induced current flow through the body and the ionosphere causes the radiation of Alfven and lower hybrid waves. This current flow...

D. E. Hastings A. Barnett S. Olbert

1988-01-01

341

N-methyl-N?-nitro-N-nitrosoguanidine-induced resistance to ionizing radiation  

Microsoft Academic Search

N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) pretreatments increase the resistance of Escherichia coli to ?-radiation. The increased resistance is dependent on functional polA, recA, recB, recC, and lexA genes and is partly dependent on recN. The MNNG-induced resistance is additive to resistance induced by pretreatment with ?-radiation but not by increases induced by hydrogen peroxide. The MNNG-induced resistance occurs in adaptive response mutants and

M. L. Morse; Diana S. Smith

1987-01-01

342

RhoA GTPase regulates radiation-induced alterations in endothelial cell adhesion and migration  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer We explore the role of RhoA in endothelial cell response to ionizing radiation. Black-Right-Pointing-Pointer RhoA is rapidly activated by single high-dose of radiation. Black-Right-Pointing-Pointer Radiation leads to RhoA/ROCK-dependent actin cytoskeleton remodeling. Black-Right-Pointing-Pointer Radiation-induced apoptosis does not require the RhoA/ROCK pathway. Black-Right-Pointing-Pointer Radiation-induced alteration of endothelial adhesion and migration requires RhoA/ROCK. -- Abstract: Endothelial cells of the microvasculature are major target of ionizing radiation, responsible of the radiation-induced vascular early dysfunctions. Molecular signaling pathways involved in endothelial responses to ionizing radiation, despite being increasingly investigated, still need precise characterization. Small GTPase RhoA and its effector ROCK are crucial signaling molecules involved in many endothelial cellular functions. Recent studies identified implication of RhoA/ROCK in radiation-induced increase in endothelial permeability but other endothelial functions altered by radiation might also require RhoA proteins. Human microvascular endothelial cells HMEC-1, either treated with Y-27632 (inhibitor of ROCK) or invalidated for RhoA by RNA interference were exposed to 15 Gy. We showed a rapid radiation-induced activation of RhoA, leading to a deep reorganisation of actin cytoskeleton with rapid formation of stress fibers. Endothelial early apoptosis induced by ionizing radiation was not affected by Y-27632 pre-treatment or RhoA depletion. Endothelial adhesion to fibronectin and formation of focal adhesions increased in response to radiation in a RhoA/ROCK-dependent manner. Consistent with its pro-adhesive role, ionizing radiation also decreased endothelial cells migration and RhoA was required for this inhibition. These results highlight the role of RhoA GTPase in ionizing radiation-induced deregulation of essential endothelial functions linked to actin cytoskeleton.

Rousseau, Matthieu; Gaugler, Marie-Helene; Rodallec, Audrey; Bonnaud, Stephanie; Paris, Francois [Inserm UMR U892, Centre de Recherche en Cancerologie Nantes-Angers CRCNA, Institut de Recherche Therapeutique IRT-UN, Universite de Nantes, 8 Quai Moncousu, BP 70721, F-44007 (France)] [Inserm UMR U892, Centre de Recherche en Cancerologie Nantes-Angers CRCNA, Institut de Recherche Therapeutique IRT-UN, Universite de Nantes, 8 Quai Moncousu, BP 70721, F-44007 (France); Corre, Isabelle, E-mail: icorre@nantes.inserm.fr [Inserm UMR U892, Centre de Recherche en Cancerologie Nantes-Angers CRCNA, Institut de Recherche Therapeutique IRT-UN, Universite de Nantes, 8 Quai Moncousu, BP 70721, F-44007 (France)] [Inserm UMR U892, Centre de Recherche en Cancerologie Nantes-Angers CRCNA, Institut de Recherche Therapeutique IRT-UN, Universite de Nantes, 8 Quai Moncousu, BP 70721, F-44007 (France)

2011-11-04

343

An internally consistent model for radiation-induced void swelling  

SciTech Connect

Most previous analytical models for radiation-induced void swelling employed reaction rate theory in which all concentrations were ''averaged out.'' The loss terms for use in such models were then usually obtained by separate, single-cell diffusion analyses which introduced various inconsistencies and uncertainties. Presented here is a unified, internally consistent analytical approach which incorporates, for the first time, the presence of dislocations, voids, and grain boundaries each with their own spatially varying diffusional fields. The results show large variations in sink strength Z-factors, usually treated as constants, significant variations in the void swelling bias factor, and quantitative levels of bias about an order of magnitude larger than most previous estimates. Good qualitative agreement is shown with available data, consistent with current concepts of close-pair annihilation in high-energy damage cascades.

Nichols, F.A.; Liu, Y.Y.

1981-01-01

344

Radiation-induced formation of cavities in amorphous germanium  

SciTech Connect

Prethinned polycrystalline Ge TEM samples were irradiated with 1.5 MeV Kr{sup +} ions at room temperature while structural and morphological changes were observed {ital in} {ital situ} in the Argonne High Voltage Electron Microscope-Tandem Facility. After a Kr{sup +} dose of 1.2{times}10{sup 14} ions/cm{sup 2}, the irradiated Ge was completely amorphized. A high density of small void-like cavities was observed after a Kr{sup +} dose of 7{times}10{sup 14} ions/cm{sup 2}. With increasing Kr{sup +} ion dose, these cavities grew into large holes transforming the irradiated Ge into a sponge-like porous material after 8.5{times}10{sup 15} ions/cm{sup 2}. The radiation-induced nucleation of void-like cavities in amorphous material is astonishing, and the final structure of the irradiated Ge with enormous surface area may have potential applications.

Wang, L.M.; Birtcher, R.C. (Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (US))

1989-12-11

345

Imaging for Assessment of Radiation-Induced Normal Tissue Effects  

SciTech Connect

Imaging can provide quantitative assessment of radiation-induced normal tissue effects. Identifying an early sign of normal tissue damage with imaging would have the potential to predict organ dysfunction, thereby allowing reoptimization of treatment strategies based on individual patients' risks and benefits. Early detection with noninvasive imaging may enable interventions to mitigate therapy-associated injury before its clinical manifestation. Furthermore, successive imaging may provide an objective assessment of the impact of such mitigation therapies. However, many problems make application of imaging to normal tissue assessment challenging, and further work is required to establish imaging biomarkers as surrogate endpoints of clinical outcome. The performance of clinical trials in which normal tissue injury is a clearly defined endpoint would greatly aid in realization of these goals.

Jeraj, Robert, E-mail: rjeraj@wisc.ed [University of Wisconsin, Madison, WI (United States); Cao Yue; Ten Haken, Randall K. [University of Michigan, Ann Arbor, MI (United States); Hahn, Carol [Duke University, Durham, NC (United States); Marks, Lawrence [Duke University, Durham, NC (United States); University of North Carolina, Chapel Hill, NC (United States)

2010-03-01

346

Radiation-induced polymerization for the immobilization of penicillin acylase  

SciTech Connect

The immobilization of Escherichia coli penicillin acylase was investigated by radiation-induced polymerization of 2-hydroxyethyl methacrylate at low temperature. A leak-proof composite that does not swell in water was obtained by adding the cross-linking agent trimethylolpropane trimethacrylate to the monomer-aqueous enzyme mixture. Penicillin acylase, which was immobilized with greater than 70% yield, possessed a higher Km value toward the substrate 6-nitro-3-phenylacetamidobenzoic acid than the free enzyme form (Km = 1.7 X 10(-5) and 1 X 10(-5) M, respectively). The structural stability of immobilized penicillin acylase, as assessed by heat, guanidinium chloride, and pH denaturation profiles, was very similar to that of the free-enzyme form, thus suggesting that penicillin acylase was entrapped in its native state into aqueous free spaces of the polymer matrix.

Boccu, E.; Carenza, M.; Lora, S.; Palma, G.; Veronese, F.M.

1987-06-01

347

Radiation-induced effects and the immune system in cancer  

PubMed Central

Chemotherapy and radiation therapy (RT) are standard therapeutic modalities for patients with cancers, and could induce various tumor cell death modalities, releasing tumor-derived antigens as well as danger signals that could either be captured for triggering anti-tumor immune response. Historic studies examining tissue and cellular responses to RT have predominantly focused on damage caused to proliferating malignant cells leading to their death. However, there is increasing evidence that RT also leads to significant alterations in the tumor microenvironment, particularly with respect to effects on immune cells and infiltrating tumors. This review will focus on immunologic consequences of RT and discuss the therapeutic reprogramming of immune responses in tumors and how it regulates efficacy and durability to RT.

Kaur, Punit; Asea, Alexzander

2012-01-01

348

Radiation-induced degradation of 4-chloroaniline in aqueous solution  

NASA Astrophysics Data System (ADS)

The radiation-induced decomposition of 4-chloroaniline (4-ClA) was studied under steady-state conditions using aqueous solutions saturated with air, pure oxygen, N 2O, argon and argon in the presence of t-Butanol. Using HPLC-method, the initial G-values of the substrate degradation as well as of a number of radiolytic products were determined. The formation of aminophenols, chlorophenols, aniline and phenol in addition to chloride, ammonia, formaldehyde and mixture of aldehydes as well as carboxylic acids was studied as a function of absorbed dose. Based on the experimental data, probable reaction mechanisms for the degradation of 4-ClA by ?-rays and the formation of the identified products are presented.

Sánchez, M.; Wolfger, H.; Getoff, N.

2002-12-01

349

Radiation-induced leukemia: Comparative studies in mouse and man  

SciTech Connect

We now have a clear understanding of the mechanism by which radiation-induced (T-cell) leukemia occurs. In irradiated mice (radiation-induced thymic leukemia) and in man (acute lymphoblastic T-cell leukemia, T-ALL) the mechanism of leukemogenesis is surprisingly similar. Expressed in the most elementary terms, T-cell leukemia occurs when T-cell differentiation is inhibited by a mutation, and pre-T cells attempt but fail to differentiate in the thymus. Instead of leaving the thymus for the periphery as functional T-cells they continue to proliferate in the thymus. The proliferating pre- (pro-) T-cells constitute the (early) acute T-cell leukemia (A-TCL). This model for the mechanism of T-cell leukemogenesis accounts for all the properties of both murine and human A-TCL. Important support for the model has recently come from work by Ilan Kirsch and others, who have shown that mutations/deletions in the genes SCL (TAL), SIL, and LCK constitute primary events in the development of T-ALL, by inhibiting differentiation of thymic pre- (pro-) T-cells. This mechanism of T-cell leukemogenesis brings several specific questions into focus: How do early A-TCL cells progress to become potently tumorigenic and poorly treatable Is it feasible to genetically suppress early and/or progressed A-TCL cells What is the mechanism by which the differentiation-inhibited (leukemic) pre-T cells proliferate During the first grant year we have worked on aspects of all three questions.

Haas, M.

1991-01-01

350

Aviation-induced cirrus and radiation changes at diurnal timescales  

NASA Astrophysics Data System (ADS)

Abstract The <span class="hlt">radiative</span> forcing from aviation-<span class="hlt">induced</span> cirrus is derived from observations and models. The annual mean diurnal cycle of airtraffic in the North Atlantic region exhibits two peaks in early morning and afternoon with different peak times in the western and eastern parts of the North Atlantic region. The same "aviation fingerprint" is found in 8 years (2004-2011) of Meteosat observations of cirrus cover and OLR. The observations are related to airtraffic data with linear response models assuming the background atmosphere without aviation to be similar to that observed in the South Atlantic. The change in OLR is interpreted as aviation-<span class="hlt">induced</span> longwave <span class="hlt">radiative</span> forcing (LW RF). The data analysis suggests an LW RF of about 600-900 mW m-2 regionally. A detailed contrail cirrus model for given global meteorology and airtraffic in 2006 gives similar results. The global RF is estimated from the ratio of global and regional RF as derived from three models. The extrapolation implies about 100-160 mW m-2 global LW RF. The models show large differences in the shortwave/longwave RF-magnitude ratio. One model computes a ratio of 0.6, implying an estimate of global net RF of about 50 mW m-2 (40-80 mW m-2). Other models suggest smaller ratios, with less cooling during day, which would imply considerably larger net effects. The sensitivity of the results to the accuracy of the observations, traffic data, and models and the estimated background is discussed.</p> <div class="credits"> <p class="dwt_author">Schumann, Ulrich; Graf, Kaspar</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">351</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/5633586"> <span id="translatedtitle"><span class="hlt">Radiation-induced</span> sarcomas of the chest wall</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Sixteen patients are presented who had sarcomas of the chest wall at a site where a prior malignancy had been irradiated. The first malignancies included breast cancer (ten cases), Hodgkin's disease (four cases), and others (two cases). <span class="hlt">Radiation</span> doses varied from 4200 to 5500 R (mean, 4900 R). The latency period ranged from 5 to 28 years (mean, 13 years). The histologic types of the <span class="hlt">radiation-induced</span> sarcomas were as follows: malignant fibrous histiocytoma, nine cases; osteosarcoma, six cases; and malignant mesenchymoma, one case. The only long-term survivor is alive and well 12 years after resection of a clavicular chondroblastic osteosarcoma. Three cases were recently diagnosed. Despite aggressive multimodality treatment, the remaining 13 patients have all died from their sarcomas (mean survival, 13.5 months). All patients have apparently been cured of their first malignancies. Chemotherapy was ineffective. No treatment, including forequarter amputation, appeared to palliate the patients with supraclavicular soft tissue sarcomas. Major chest wall resection offered good palliation for seven of eight patients with sarcomas arising in the sternum or lateral chest wall. Close follow-up is needed to detect signs of these sarcomas in the ever-increasing number of patients receiving therapeutic irradiation.</p> <div class="credits"> <p class="dwt_author">Souba, W.W.; McKenna, R.J. Jr.; Meis, J.; Benjamin, R.; Raymond, A.K.; Mountain, C.F.</p> <p class="dwt_publisher"></p> <p class="publishDate">1986-02-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">352</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1996AdSpR..18...99D"> <span id="translatedtitle"><span class="hlt">Radiation-induced</span> chromosomal instability in human mammary epithelial cells</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Karyotypes of human cells surviving X- and alpha-irradiation have been studied. Human mammary epithelial cells of the immortal, non-tumorigenic cell line H184B5 F5-1 M/10 were irradiated and surviving clones isolated and expanded in culture. Cytogenetic analysis was performed using dedicated software with an image analyzer. We have found that both high- and low-LET <span class="hlt">radiation</span> <span class="hlt">induced</span> chromosomal instability in long-term cultures, but with different characteristics. Complex chromosomal rearrangements were observed after X-rays, while chromosome loss predominated after alpha-particles. Deletions were observed in both cases. In clones derived from cells exposed to alpha-particles, some cells showed extensive chromosome breaking and double minutes. Genomic instability was correlated to delayed reproductive death and neoplastic transformation. These results indicate that chromosomal instability is a <span class="hlt">radiation</span>-quality-dependent effect which could determine late genetic effects, and should therefore be carefully considered in the evaluation of risk for space missions.</p> <div class="credits"> <p class="dwt_author">Durante, M.; Grossi, G. F.; Yang, T. C.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">353</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3180059"> <span id="translatedtitle"><span class="hlt">Radiation-induced</span> tumor neoantigens: imaging and therapeutic implications</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Exposure of tumor cells to ionizing <span class="hlt">radiation</span> (IR) is widely known to <span class="hlt">induce</span> a number of cellular changes. One way that IR can affect tumor cells is through the development of neoantigens which are new molecules that tumor cells express at the cell membrane following some insult or change to the cell. There have been numerous reports in the literature of changes in both tumor and tumor vasculature cell surface molecule expression following treatment with IR. The usefulness of neoantigens for imaging and therapeutic applications lies in the fact that they are differentially expressed on the surface of irradiated tumor cells to a greater extent than on normal tissues. This differential expression provides a mechanism by which tumor cells can be “marked” by <span class="hlt">radiation</span> for further targeting. Drug delivery vehicles or imaging agents conjugated to ligands that recognize and interact with the neoantigens can help to improve tumor-specific targeting and reduce systemic toxicity with cancer drugs. This article provides a review of the molecules that have been reported to be expressed on the surface of tumor cells in response to IR either in vivo or in vitro. Additionally, we provide a discussion of some of the methods used in the identification of these antigens and applications for their use in drug delivery and imaging.</p> <div class="credits"> <p class="dwt_author">Corso, Christopher D; Ali, Arif N; Diaz, Roberto</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">354</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/24180216"> <span id="translatedtitle">Ionizing <span class="hlt">radiation-induced</span> DNA damage, response, and repair.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Abstract Significance: Ionizing <span class="hlt">radiation</span> (IR) is an effective and commonly employed treatment in the management of more than half of human malignancies. Because IR's ability to control tumors mainly relies on DNA damage, the cell's DNA damage response and repair (DRR) processes may hold the key to determining tumor responses. IR-<span class="hlt">induced</span> DNA damage activates a number of DRR signaling cascades that control cell cycle arrest, DNA repair, and the cell's fate. DNA double-strand breaks (DSBs) generated by IR are the most lethal form of damage, and are mainly repaired via either homologous recombination (HR) or nonhomologous end-joining (NHEJ) pathways. Recent Advances: In recent years, immense effort to understand and exploit the differences in the use of these repair pathways between tumors and normal cells will allow for an increase in tumor cell killing and a decrease in normal tissue injury. Critical Issues: Regulation of the two major DSB repair mechanisms (HR and NHEJ) and new strategies, which may improve the therapeutic ratio of <span class="hlt">radiation</span> by differentially targeting HR and NHEJ function in tumor and normal tissues, is of intense interest currently, and is the focus of this article. Future Directions: By utilizing the strategies outlined above, it may be possible to exploit differences between tumor and somatic cell DRR pathways, specifically their DSB repair mechanisms, to improve the therapeutic ratio of IR. Antioxid. Redox Signal. 21, 251-259. PMID:24180216</p> <div class="credits"> <p class="dwt_author">Santivasi, Wil L; Xia, Fen</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-07-10</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">355</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2002cosp...34E.583S"> <span id="translatedtitle"><span class="hlt">Radiation-induced</span> radioresistance of mammals and risk assessment</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">It is shown experimentally that a preliminary low dose exposure can <span class="hlt">induce</span> radioresistance in mice in two (early and late) periods after preirradiation. The manifestation of such effects is reduced mortality of pre-exposed specimens after challenge acute irradiation, the reason of the animal death being the hematopoietic subsyndrome of the acute <span class="hlt">radiation</span> syndrome. Therefore, proceeding from the radiobiological concept of the critical system, the theoretical investigation of the influence of preirradiation on mammalian radiosensitivity is conducted by making use of mathematical models of the vital body system, hematopoiesis. Modeling results make it possible to elucidate the mechanisms of the radioprotection effect of low level priming irradiation on mammals. Specifically, the state of acquired radioresistance in mice is caused by reduced radiosensitivity of lymphopoietic and thrombocytopoietic systems in the early period and by reduced radiosensitivity of granulocytopoietic system in the late period after preirradiation. It is important to emphasize that the evaluations of the duration of the early and late periods of postirradiation radioresistance in mice, carried out on the basis of the modeling and experimental investigations, practically coincide. All this demonstrates the effectiveness of joint modeling and experimental methods in studies and predictions of modification effects of preirradiation on mammalian radiosensitivity. The results obtained show the importance of accounting such effects in <span class="hlt">radiation</span> risk assessments for cosmonauts and astronauts on long-term missions.</p> <div class="credits"> <p class="dwt_author">Smirnova, O.; Yonezawa, M.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">356</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014ApPhL.104w3109C"> <span id="translatedtitle"><span class="hlt">Radiation</span> <span class="hlt">induced</span> effects on mechanical properties of nanoporous gold foams</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">It has recently been shown that due to a high surface-to-volume ratio, nanoporous materials display <span class="hlt">radiation</span> tolerance. The abundance of surfaces, which are perfect sinks for defects, and the relation between ligament size, defect diffusion, and time combine to define a window of <span class="hlt">radiation</span> resistance [Fu et al., Appl. Phys. Lett. 101, 191607 (2012)]. Outside this window, the dominant defect created by irradiation in Au nanofoams are stacking fault tetrahedra (SFT). Molecular dynamics computer simulations of nanopillars, taken as the elemental constituent of foams, predict that SFTs act as dislocation sources <span class="hlt">inducing</span> softening, in contrast to the usual behavior in bulk materials, where defects are obstacles to dislocation motion, producing hardening. In this work we test that prediction and answer the question whether irradiation actually hardens or softens a nanofam. Ne ion irradiations of gold nanofoams were performed at room temperature for a total dose up to 4 dpa, and their mechanical behavior was measured by nanoindentation. We find that hardness increases after irradiation, a result that we analyze in terms of the role of SFTs on the deformation mode of foams.</p> <div class="credits"> <p class="dwt_author">Caro, M.; Mook, W. M.; Fu, E. G.; Wang, Y. Q.; Sheehan, C.; Martinez, E.; Baldwin, J. K.; Caro, A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-06-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">357</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014NIMPB.326...86C"> <span id="translatedtitle">Preliminary results on the relationship between luminescence and <span class="hlt">crystalline</span> structure of lithium metatitanate</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Lithium metatitanate is a luminescent ceramic material of promising properties for numerous applications (breeder blanket in fusion reactors, ionic conductors). In some cases, the material will be submitted to aggressive environments (<span class="hlt">radiation</span>, chemicals, high temperatures), which could <span class="hlt">induce</span> changes in the <span class="hlt">crystalline</span> structure. Small variations (presence of inclusions, impurities, or surface) in the lattice of <span class="hlt">crystalline</span> solids are known to change the light emission behaviour, i.e. intensity and wavelength position of photoluminescence. Li2TiO3 ceramic samples were sintered in the range of 1050 and 1350 °C to modify the high temperature <span class="hlt">crystalline</span> structure, and then were characterized by means of their cathodoluminescence (CL) and thermoluminescence (TL) properties as a function of total <span class="hlt">radiation</span> dose and time of storage.</p> <div class="credits"> <p class="dwt_author">Correcher, V.; González, M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">358</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2043523"> <span id="translatedtitle">Snai2 Expression Enhances Ultraviolet <span class="hlt">Radiation-Induced</span> Skin Carcinogenesis</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Snai2, encoded by the SNAI2 gene, has been shown to modulate epithelial-mesenchymal transformation (EMT), the conversion of sessile epithelial cells attached to adjacent cells and to the basement membrane into dissociated and motile fibroblastic cells. EMT occurs during development, wound healing, and carcinoma progression. Using Snai2-null mice (Snai2lacZ), we evaluated the role of Snai2 in UV <span class="hlt">radiation</span> (UVR)-<span class="hlt">induced</span> skin carcinogenesis. In chronically UVR-exposed nontumor-bearing skin from Snai2-null mice, inflammation and epidermal proliferation were decreased compared with wild-type (+/+) skin. Snai2-null mice had a consistently lower tumor burden than +/+ mice. In addition, null mice developed fewer aggressive spindle cell tumors, believed to arise from squamous cell carcinomas that have undergone EMT, than +/+ mice; however, the difference in tumor type distribution between the two genotypes was not statistically significant. No metastases were observed in either the +/+ or Snai2-null mice. Using quantitative reverse transcriptase-polymerase chain reaction and immunohistochemistry, we showed that the spindle cell tumors in the Snai2-null mice demonstrated impaired EMT, as shown by decreased vimentin and increased cadherin 1 expression. This study confirms a role for Snai2 in EMT, but demonstrates that Snai2 expression is not required for the development or progression of UVR-<span class="hlt">induced</span> skin tumors.</p> <div class="credits"> <p class="dwt_author">Newkirk, Kimberly M.; Parent, Allison E.; Fossey, Stacey L.; Choi, Changsun; Chandler, Heather L.; Rajala-Schultz, Paivi J.; Kusewitt, Donna F.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">359</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009JPES....3..216H"> <span id="translatedtitle">Mechanism of Hydrophilicity by <span class="hlt">Radiation-Induced</span> Surface Activation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">When a metal oxide is irradiated by gamma rays, the irradiated surface becomes hydrophilic. This surface phenomenon is called as <span class="hlt">radiation-induced</span> surface activation (RISA) hydrophilicity. In order to investigate gamma ray-<span class="hlt">induced</span> and photoinduced hydrophilicity, the contact angles of water droplets on a titanium dioxide surface were measured in terms of irradiation intensity and time for gamma rays of cobalt-60 and for ultraviolet rays. Reciprocals of the contact angles increased in proportion to the irradiation time before the contact angles reached its super-hydrophilic state. The irradiation time dependency is equal to each other qualitatively. In addition, an effect of ambient gas was investigated. In pure argon gas, the contact angle remains the same against the irradiation time. This clearly indicates that certain humidity is required in ambient gas to take place of RISA hydrophilicity. A single crystal titanium dioxide (100) surface was analyzed by X-ray photoelectron spectrometry (XPS). After irradiation with gamma rays, a peak was found in the O1s spectrum, which indicates the adsorption of dissociative water to a surface 5-fold coordinate titanium site, and the formation of a surface hydroxyl group. We conclude that the RISA hydrophilicity is caused by chemisorption of the hydroxyl group on the surface.</p> <div class="credits"> <p class="dwt_author">Honjo, Yoshio; Furuya, Masahiro; Takamasa, Tomoji; Okamoto, Koji</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">360</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012PhRvB..85t5211S"> <span id="translatedtitle"><span class="hlt">Radiation</span> <span class="hlt">induced</span> recombination centers in organic solar cells</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Prolonged x-ray exposure of bulk heterojunction organic solar cells <span class="hlt">induces</span> deep trap states that are observed in measurements of the photocurrent spectral response. The density of <span class="hlt">induced</span> trap states is proportional to the density of recombination centers as measured by the voltage dependence of the photocurrent, therefore identifying the traps as primary recombination centers. The states are reversible by thermal annealing to about 100 °C, which implies a metastable structural change with binding energy 1-1.2 eV. However, the annealing kinetics reveal three different annealing processes, although for defect states with essentially the same electronic character. Analysis of the <span class="hlt">radiation</span> damage indicates that defects are formed by hydrogen release from C-H bonds due to electronic excitation by the energetic secondary electrons created by the x rays. Theoretical structure calculations of possible hydrogen-related defects find specific defect states that match the experimental observations and provide values for hydrogen migration energies that are consistent with the annealing kinetics. The effects of prolonged white light exposure are very similar to x-ray exposure, although the annealing kinetics are significantly different. Measurements of the spectral response with bias illumination provide information about the energy level of the localized states.</p> <div class="credits"> <p class="dwt_author">Street, R. A.; Northrup, J. E.; Krusor, B. S.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-05-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_17");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' href="#">4</a> <a onClick='return showDiv("page_5");' href="#">5</a> <a onClick='return showDiv("page_6");' href="#">6</a> <a onClick='return showDiv("page_7");' href="#">7</a> <a onClick='return showDiv("page_8");' href="#">8</a> <a onClick='return showDiv("page_9");' href="#">9</a> <a onClick='return showDiv("page_10");' href="#">10</a> <a onClick='return showDiv("page_11");' href="#">11</a> <a onClick='return showDiv("page_12");' href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a style="font-weight: bold;">18</a> <a onClick='return showDiv("page_19");' href="#">19</a> <a onClick='return showDiv("page_20");' href="#">20</a> <a onClick='return showDiv("page_21");' href="#">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_19");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> </div><!-- page_18 div --> <div id="page_19" class="hiddenDiv"> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_18");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' href="#">4</a> <a onClick='return showDiv("page_5");' href="#">5</a> <a onClick='return showDiv("page_6");' href="#">6</a> <a onClick='return showDiv("page_7");' href="#">7</a> <a onClick='return showDiv("page_8");' href="#">8</a> <a onClick='return showDiv("page_9");' href="#">9</a> <a onClick='return showDiv("page_10");' href="#">10</a> <a onClick='return showDiv("page_11");' href="#">11</a> <a onClick='return showDiv("page_12");' href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a onClick='return showDiv("page_18");' href="#">18</a> <a style="font-weight: bold;">19</a> <a onClick='return showDiv("page_20");' href="#">20</a> <a onClick='return showDiv("page_21");' href="#">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_20");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">361</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/19738419"> <span id="translatedtitle">Mitochondrial ROS and <span class="hlt">radiation</span> <span class="hlt">induced</span> transformation in mouse embryonic fibroblasts.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Manganese superoxide dismutase (SOD2) is a nuclear encoded and mitochondria localized antioxidant enzyme that converts mitochondria derived superoxide to hydrogen peroxide. This study investigates the hypothesis that mitochondria derived reactive oxygen species (ROS) regulate ionizing <span class="hlt">radiation</span> (IR) <span class="hlt">induced</span> transformation in normal cells. Mouse embryonic fibroblasts (MEFs) with wild type SOD2 (+/+), heterozygous SOD2 (+/-), and homozygous SOD2 (-/-) genotypes were irradiated with equitoxic doses of IR, and assayed for transformation frequency, cellular redox environment, DNA damage, and cell cycle checkpoint activation. Transformation frequency increased ( approximately 5-fold) in SOD2 (-/-) compared to SOD2 (+/+) MEFs. Cellular redox environment (GSH, GSSG, DHE and DCFH-oxidation) did not show any significant change within 24 h post-IR. However, a significant increase in cellular ROS levels was observed at 72 h post-IR in SOD2 (-/-) compared to SOD2 (+/+) MEFs, which was consistent with an increase in GSSG in SOD2 (-/-) MEFs. Late ROS accumulation was associated with an increase in micronuclei frequency in SOD2 (-/-) MEFs. Exit from G(2) was accelerated in irradiated SOD2 (+/-) and SOD2 (-/-) compared to SOD2 (+/+) MEFs. These results support the hypothesis that SOD2 activity and mitochondria generated ROS regulate IR <span class="hlt">induced</span> transformation in mouse embryonic fibroblasts. PMID:19738419</p> <div class="credits"> <p class="dwt_author">Du, Changbin; Gao, Zhen; Venkatesha, Venkatasubbaiah A; Kalen, Amanda L; Chaudhuri, Leena; Spitz, Douglas R; Cullen, Joseph J; Oberley, Larry W; Goswami, Prabhat C</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">362</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/20706262"> <span id="translatedtitle"><span class="hlt">Radiation-induced</span> osteosarcomas in the pediatric population</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Purpose: <span class="hlt">Radiation-induced</span> osteosarcomas (R-OS) have historically been high-grade, locally invasive tumors with a poor prognosis. The purpose of this study was to perform a comprehensive literature review and analysis of reported cases dealing with R-OS in the pediatric population to identify the characteristics, prognostic factors, optimal treatment modalities, and overall survival of these patients. Methods and Materials: A MEDLINE/PubMed search of articles written in the English language dealing with OSs occurring after radiotherapy (RT) in the pediatric population yielded 30 studies from 1981 to 2004. Eligibility criteria included patients <21 years of age at the diagnosis of the primary cancer, cases satisfying the modified Cahan criteria, and information on treatment outcome. Factors analyzed included the type of primary cancer treated with RT, the <span class="hlt">radiation</span> dose and beam energy, the latency period between RT and the development of R-OS, and the treatment, follow-up, and final outcome of R-OS. Results: The series included 109 patients with a median age at the diagnosis of primary cancer of 6 years (range, 0.08-21 years). The most common tumors treated with RT were Ewing's sarcoma (23.9%), rhabdomyosarcoma (17.4%), retinoblastoma (12.8%), Hodgkin's disease (9.2%), brain tumor (8.3%), and Wilms' tumor (6.4%). The median <span class="hlt">radiation</span> dose was 47 Gy (range, 15-145 Gy). The median latency period from RT to the development of R-OS was 100 months (range, 36-636 months). The median follow-up after diagnosis of R-OS was 18 months (1-172 months). The 3- and 5-year cause-specific survival rate was 43.6% and 42.2%, respectively, and the 3- and 5-year overall survival rate was 41.7% and 40.2%, respectively. Variables, including age at RT, primary site, type of tumor treated with RT, total <span class="hlt">radiation</span> dose, and latency period did not have a significant effect on survival. The 5-year cause-specific and overall survival rate for patients who received treatment for R-OS involving chemotherapy alone, surgery alone, and surgery plus chemotherapy was 17.3% and 17.3%, 56.6% and 50.3%, and 71.0% and 68.3%, respectively (p < 0.0001, log-rank test). Conclusion: The type of treatment for R-OS was the most significant factor for cause-specific and overall survival. Patients who develop R-OS should be aggressively treated, because the outcome is not as dismal as once thought.</p> <div class="credits"> <p class="dwt_author">Koshy, Matthew [Department of Radiology, Division of Radiation Oncology, Baylor College of Medicine, Methodist Hospital, and Texas Children's Hospital, Houston, TX (United States); Paulino, Arnold C. [Department of Radiology, Division of Radiation Oncology, Baylor College of Medicine, Methodist Hospital, and Texas Children's Hospital, Houston, TX (United States)]. E-mail: apaulino@tmh.tmc.edu; Mai, Wei Y. [Department of Radiology, Division of Radiation Oncology, Baylor College of Medicine, Methodist Hospital, and Texas Children's Hospital, Houston, TX (United States); Teh, Bin S. [Department of Radiology, Division of Radiation Oncology, Baylor College of Medicine, Methodist Hospital, and Texas Children's Hospital, Houston, TX (United States)</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-11-15</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">363</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/24902516"> <span id="translatedtitle">Oxygen vacancy <span class="hlt">induced</span> selective silver deposition on the {001} facets of BiOCl single-<span class="hlt">crystalline</span> nanosheets for enhanced Cr(vi) and sodium pentachlorophenate removal under visible light.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">We demonstrate that the high oxygen density characteristic of BiOCl {001} facets ensures the fast generation of oxygen vacancies in ethylene glycol under microwave irradiation, resulting in in situ nucleation and growth of Ag on the {001} facets of BiOCl single-<span class="hlt">crystalline</span> nanosheets. The resulting Ag selectively deposited BiOCl single-<span class="hlt">crystalline</span> nanosheets exhibit much higher reactivity and stability on both Cr(vi) reduction and sodium pentachlorophenate oxidation than the randomly deposited counterparts under visible light because of the tight contact between Ag and the {001} facets of BiOCl arisen from oxygen vacancy <span class="hlt">induced</span> selective silver deposition. PMID:24902516</p> <div class="credits"> <p class="dwt_author">Li, Hao; Zhang, Lizhi</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-06-26</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">364</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/21608123"> <span id="translatedtitle">Deep Level Transient Spectroscopy Technique to Analyze <span class="hlt">Radiation</span> <span class="hlt">Induced</span> Defects in Power Transistors</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Deep Level Transient Spectroscopy (DLTS) technique is useful tool to study process and <span class="hlt">radiation</span> <span class="hlt">induced</span> defects in semiconductor materials and devices. The different types of <span class="hlt">radiation</span> <span class="hlt">induced</span> trap levels in the collector-base depletion region of the transistors were studied by DLTS technique.</p> <div class="credits"> <p class="dwt_author">Prakash, A. P. Gnana [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore, Karnataka-570006 (India)</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-07-15</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">365</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/29243910"> <span id="translatedtitle">Early hyperbaric oxygen therapy improves outcome for <span class="hlt">radiation-induced</span> hemorrhagic cystitis</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">ObjectivesTo assess the clinical factors that affect the efficacy of hyperbaric oxygen (HBO2) therapy in treating <span class="hlt">radiation-induced</span> hemorrhagic cystitis. HBO2 therapy is an effective treatment for <span class="hlt">radiation-induced</span> hemorrhagic cystitis, with reported response rates ranging from 76% to 100%.</p> <div class="credits"> <p class="dwt_author">Kian Tai Chong; Neil B. Hampson; John M. Corman</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">366</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011AIPC.1349.1077P"> <span id="translatedtitle">Deep Level Transient Spectroscopy Technique to Analyze <span class="hlt">Radiation</span> <span class="hlt">Induced</span> Defects in Power Transistors</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Deep Level Transient Spectroscopy (DLTS) technique is useful tool to study process and <span class="hlt">radiation</span> <span class="hlt">induced</span> defects in semiconductor materials and devices. The different types of <span class="hlt">radiation</span> <span class="hlt">induced</span> trap levels in the collector-base depletion region of the transistors were studied by DLTS technique.</p> <div class="credits"> <p class="dwt_author">Prakash, A. P. Gnana</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-07-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">367</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/41977539"> <span id="translatedtitle"><span class="hlt">Radiation</span> from large space structures in low earth orbit with <span class="hlt">induced</span> alternating currents</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Large conducting space structures in low Earth orbit will have a nonnegligible motionally <span class="hlt">induced</span> potential across their structures. The <span class="hlt">induced</span> current flow through the body and the ionosphere causes the <span class="hlt">radiation</span> of Alfvén and lower hybrid waves. This current flow is taken to be ac, and the <span class="hlt">radiated</span> power is studied as a function of the ac frequency. The current</p> <div class="credits"> <p class="dwt_author">D. E. Hastings; A. Barnett; S. Olbert</p> <p class="dwt_publisher"></p> <p class="publishDate">1988-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">368</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/6847782"> <span id="translatedtitle">Colitis cystica profunda occurring in a <span class="hlt">radiation-induced</span> colonic stricture</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Localized colitis cystica profunda developed in a fibrotic <span class="hlt">radiation-induced</span> colonic stricture 17 years after pelvic <span class="hlt">radiation</span> for squamous carcinoma of cervix. This uncommon pathologic entity must be distinguished from invasive adenocarcinoma of colon, and colonic <span class="hlt">radiation</span> injury should be included with other conditions associated with colitis cystica profunda.</p> <div class="credits"> <p class="dwt_author">Gardiner, G.W.; McAuliffe, N.; Murray, D.</p> <p class="dwt_publisher"></p> <p class="publishDate">1984-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">369</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://cbrl.stanford.edu/mbrown/pdf/nagar03.pdf"> <span id="translatedtitle">Characterization of a Novel Epigenetic Effect of Ionizing <span class="hlt">Radiation</span>: The Death-<span class="hlt">Inducing</span> Effect1</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The detrimental effects associated with exposure to ionizing <span class="hlt">radiation</span> have long been thought to result from the direct targeting of the nucleus leading to DNA damage; however, the emergence of concepts such as <span class="hlt">radiation-induced</span> genomic instability and bystander effects have chal- lenged this dogma. After cellular exposure to ionizing <span class="hlt">radiation</span>, we have isolated a number of clones of Chinese hamster-human</p> <div class="credits"> <p class="dwt_author">Shruti Nagar; Leslie E. Smith; William F. Morgan</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">370</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4014155"> <span id="translatedtitle">Increased radiosensitivity and <span class="hlt">radiation-induced</span> apoptosis in SRC-3 knockout mice</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Steroid receptor coactivator-3 (SRC-3), a multifunctional transcriptional coactivator, plays an important role in regulation of cell apoptosis in chemoresistant cancer cells. However, its role in <span class="hlt">radiation-induced</span> apoptosis in hematopoietic cells is still unclear. In this study, we used SRC-3 knockout (SRC-3-/-) mice to assess the role of SRC-3 in <span class="hlt">radiation-induced</span> hematopoietic injury in vivo. After a range of doses of irradiation, SRC-3-/- mice exhibited lower counts of peripheral blood cells and bone marrow (BM) mononuclear cells and excessive BM depression, which resulted in a significantly higher mortality compared with wildtype mice. Moreover, BM mononuclear cells obtained from SRC-3-/- mice showed a remarkable increase in <span class="hlt">radiation-induced</span> apoptosis. Collectively, our data demonstrate that SRC-3 plays a role in <span class="hlt">radiation-induced</span> apoptosis of BM hematopoietic cells. Regulation of SRC-3 might influence the radiosensitivity of hematopoietic cells, which highlights a potential therapeutic target for <span class="hlt">radiation-induced</span> hematopoietic injury.</p> <div class="credits"> <p class="dwt_author">Jin, Jie; Wang, Yu; Wang, Jin; Xu, Yang; Chen, Shilei; Wang, Junping; Ran, Xinze; Su, Yongping</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">371</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/7198897"> <span id="translatedtitle">Time dependent annealing of <span class="hlt">radiation</span> - <span class="hlt">induced</span> leakage currents in MOS devices</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Results are presented showing the <span class="hlt">radiation</span> response of several unhardened commercial 1.25-{mu}m bulk CMOS processes using LOCOS isolation technology. In all cases studied <span class="hlt">radiation-induced</span> failure is caused by effects in the field oxide, and the <span class="hlt">radiation-induced</span> {delta}V{sub T} in the channel region is usually small at the failure dose. Time dependent leakage current data for the field oxides are presented and discussed.</p> <div class="credits"> <p class="dwt_author">Terrell, J.M. (Booz Allen and Hamilton, Inc. Bethesda, MD (US)); Olkham, T.R.; Lelis, A.J.; Benedetto, J.M. (Harry Diamond Labs., Adelphi, MD (US))</p> <p class="dwt_publisher"></p> <p class="publishDate">1989-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">372</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1999NIMPB.148..573L"> <span id="translatedtitle">Binary collision approximation modeling of ion-<span class="hlt">induced</span> damage effects in <span class="hlt">crystalline</span> 6H-SiC</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Disorder accumulation in ion implanted 6H-SiC and the associated surface swelling are simulated with a Monte Carlo binary collision code. The parameters of the models used in the program are adjusted through the comparison with previously reported data obtained from 0.5 MeV Al + implantation at room temperature. The evolution of damage profiles, as determined with the Rutherford Backscattering-Channeling technique, can be described by the linear cascade approximation, provided that apparent atomic displacement energies much smaller than commonly referred values are used. This observation indicates that, in spite of the reported high individual displacement threshold energies, SiC is very sensitive to collective disordering effects <span class="hlt">induced</span> by ion irradiation. Swelling can be modeled assuming a linear dependence of surface shift on the integral of damage in the disordered crystal, plus a contribution of the relaxation which occurs at the onset of crystal-to-amorphous transition.</p> <div class="credits"> <p class="dwt_author">Lulli, G.; Albertazzi, E.; Bianconi, M.; Nipoti, R.</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">373</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/837474"> <span id="translatedtitle"><span class="hlt">Radiation-Induced</span> Topological Disorder in Irradiated Network Structures</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">This report summarizes results of a research program investigating the fundamental principles underlying the phenomenon of topological disordering in a <span class="hlt">radiation</span> environment. This phenomenon is known popularly as amorphization, but is more formally described as a process of <span class="hlt">radiation-induced</span> structural arrangement that leads in crystals to loss of long-range translational and orientational correlations and in glasses to analogous alteration of connectivity topologies. The program focus has been on a set compound ceramic solids with directed bonding exhibiting structures that can be described as networks. Such solids include SiO2, Si3N4, SiC, which are of interest to applications in fusion energy production, nuclear waste storage, and device manufacture involving ion implantation or use in <span class="hlt">radiation</span> fields. The principal investigative tools comprise a combination of experimental diffraction-based techniques, topological modeling, and molecular-dynamics simulations that have proven a rich source of information in the preceding support period. The results from the present support period fall into three task areas. The first comprises enumeration of the rigidity constraints applying to (1) more complex ceramic structures (such as rutile, corundum, spinel and olivine structures) that exhibit multiply polytopic coordination units or multiple modes of connecting such units, (2) elemental solids (such as graphite, silicon and diamond) for which a correct choice of polytope is necessary to achieve correct representation of the constraints, and (3) compounds (such as spinel and silicon carbide) that exhibit chemical disorder on one or several sublattices. With correct identification of the topological constraints, a unique correlation is shown to exist between constraint and amorphizability which demonstrates that amorphization occurs at a critical constraint loss. The second task involves the application of molecular dynamics (MD) methods to topologically-generated models of amorphized network silicas. These methods are shown to generate fully connected topologically-disordered networks, equilibrated to achieve accurately-specified atomic coordinates that can be compared to correlation data derived from diffraction experiments. The MD equilibrations demonstrate the insensitivity of diffraction methods to substantial differences in intermediate-range topology, with the exception of the first diffraction peak which is shown to be uniquely sensitive to topological differences. The third task concerns application of MD simulations to amorphization of silicon carbide, which exhibits anomalous amorphizability. Amorphization of this compound is shown to derive from its facility for tolerating chemical disorder, and a critical homonuclear bond density threshold is established as a criterion for its amorphization.</p> <div class="credits"> <p class="dwt_author">Hobbs, Linn W.</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-12-21</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">374</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/24813621"> <span id="translatedtitle">Autophagy promotes <span class="hlt">radiation-induced</span> senescence but inhibits bystander effects in human breast cancer cells.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Ionizing <span class="hlt">radiation</span> <span class="hlt">induces</span> cellular senescence to suppress cancer cell proliferation. However, it also <span class="hlt">induces</span> deleterious bystander effects in the unirradiated neighboring cells through the release of senescence-associated secretory phenotypes (SASPs) that promote tumor progression. Although autophagy has been reported to promote senescence, its role is still unclear. We previously showed that <span class="hlt">radiation</span> <span class="hlt">induces</span> senescence in PTTG1-depleted cancer cells. In this study, we found that autophagy was required for the <span class="hlt">radiation-induced</span> senescence in PTTG1-depleted breast cancer cells. Inhibition of autophagy caused the cells to switch from <span class="hlt">radiation-induced</span> senescence to apoptosis. Senescent cancer cells exerted bystander effects by promoting the invasion and migration of unirradiated cells through the release of CSF2 and the subsequently activation of the JAK2-STAT3 and AKT pathways. However, the <span class="hlt">radiation-induced</span> bystander effects were correlated with the inhibition of endogenous autophagy in bystander cells, which also resulted from the activation of the CSF2-JAK2 pathway. The induction of autophagy by rapamycin reduced the <span class="hlt">radiation-induced</span> bystander effects. This study reveals, for the first time, the dual role of autophagy in <span class="hlt">radiation-induced</span> senescence and bystander effects. PMID:24813621</p> <div class="credits"> <p class="dwt_author">Huang, Yao-Huei; Yang, Pei-Ming; Chuah, Qiu-Yu; Lee, Yi-Jang; Hsieh, Yi-Fen; Peng, Chih-Wen; Chiu, Shu-Jun</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-07-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">375</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/52362251"> <span id="translatedtitle">Tunable terahertz <span class="hlt">radiation</span> from an ultrashort-laser-pulse-<span class="hlt">induced</span> discharge in biased air</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Strong beams of coherent <span class="hlt">radiation</span> are essential to <span class="hlt">induce</span> nonlinear excitation phenomena in biology and material sciences. Optical-field-<span class="hlt">induced</span> ionization by an ultrashort laser pulse produces ultrabroadband bursts of <span class="hlt">radiation</span> with photon energies ranging from radio-wave at the microsecond timescale to x-ray at the attosecond timescale. As the laser pulse drives an ultrafast-discharge with high current it <span class="hlt">induces</span> nonlinear spectral conversion</p> <div class="credits"> <p class="dwt_author">Fuminori Suzuki; Hiroaki Anno-Kashiwazaki; Jun Miyazawa; Shohei Ono; Takeshi Higashiguchi; Noboru Yugami; Yasuhiko Sentoku; Ryosuke Kodama; Patric Muggli</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">376</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/21062132"> <span id="translatedtitle">Single <span class="hlt">crystalline</span> BaTiO{sub 3} thin films synthesized using ion implantation <span class="hlt">induced</span> layer transfer</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Layer transfer of BaTiO{sub 3} thin films onto silicon-based substrates has been investigated. Hydrogen and helium ions were co-implanted to facilitate ion-implantation-<span class="hlt">induced</span> layer transfer of films from BaTiO{sub 3} single crystals. From thermodynamic equilibrium calculations, we suggest that the dominant species during cavity nucleation and growth are H{sub 2}, H{sup +}, H{sub 2}O, Ba{sup 2+} and Ba-OH, and that the addition of hydrogen to the Ba-Ti-O system can effectively suppress volatile oxide formation during layer transfer and subsequent annealing. After ion implantation, BaTiO{sub 3} layers contain microstructural defects and hydrogen precipitates in the lattice, but after layer transfer, the single crystal is found to be stoichiometric. Using direct wafer bonding and layer splitting, single crystal BaTiO{sub 3} thin films were transferred onto amorphous Si{sub 3}N{sub 4} and Pt substrates. Micro-Raman spectroscopy indicated that the density of defects generated by ion implantation in BaTiO{sub 3} can be significantly reduced during post-transfer annealing, returning the transferred layer to its single crystal state. Characterization using piezoresponse force microscopy shows that the layer transferred thin films are ferroelectric, with domain structures and piezoresponse characteristics similar to that of bulk crystals.</p> <div class="credits"> <p class="dwt_author">Park, Young-Bae; Diest, Kenneth; Atwater, Harry A. [Thomas J. Watson Laboratory of Applied Physics, California Institute of Technology, Pasadena, California 91125 (United States)</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-10-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">377</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/20486661"> <span id="translatedtitle">Sodium bicarbonate <span class="hlt">induces</span> <span class="hlt">crystalline</span> wax generation, activates host-resistance, and increases imazalil level in rind wounds of oranges, improving the control of green mold during storage.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Imazalil (IMZ) was quantified in the flavedo and albedo (Citrus fruits outer and inner tissue of the exocarp) of wounded and unwounded Valencia L. Olinda oranges following a 2 min immersion at 25 degrees C in 50, 100, or 250 microg mL(-1) of the fungicide mixture with or without 3% sodium bicarbonate (SBC). The addition of SBC significantly reduced the decay incidence throughout 30 d of storage at 10 degrees C with 95% RH and 6 d of simulated marketing period at 25 degrees C and 75% RH. In unwounded oranges, IMZ uptake was not changed by the coapplication of SBC, and the fungicide was predominantly recovered in the flavedo. To the contrary, in the albedo of wounded fruit, the residue level increased by about 6-fold when the fungicide was applied with SBC. When SBC was coapplied to wounded fruit, the phytoalexin scoparone was <span class="hlt">induced</span> in the albedo and the accumulation was not affected by IMZ. When fruit was treated with SBC, scanning electron microscopy observations evidenced a production of <span class="hlt">crystalline</span> wax patches with branched stripes and the magnitude was positively correlated to the salt concentration in the mixture. The generation as fast as 24 h post-treatment, and the different morphology of the new wax suggests a displacement of intracuticular waxes which can affect the fungicide sorption and diffusion coefficient into the rind. PMID:20486661</p> <div class="credits"> <p class="dwt_author">Dore, Antonio; Molinu, Maria Giovanna; Venditti, Tullio; D'Hallewin, Guy</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-06-23</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">378</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3928108"> <span id="translatedtitle">A Novel <span class="hlt">Radiation-Induced</span> p53 Mutation Is Not Implicated in <span class="hlt">Radiation</span> Resistance via a Dominant-Negative Effect</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Understanding the mutations that confer <span class="hlt">radiation</span> resistance is crucial to developing mechanisms to subvert this resistance. Here we describe the creation of a <span class="hlt">radiation</span> resistant cell line and characterization of a novel p53 mutation. Treatment with 20 Gy <span class="hlt">radiation</span> was used to <span class="hlt">induce</span> mutations in the H460 lung cancer cell line; <span class="hlt">radiation</span> resistance was confirmed by clonogenic assay. Limited sequencing was performed on the resistant cells created and compared to the parent cell line, leading to the identification of a novel mutation (del) at the end of the DNA binding domain of p53. Levels of p53, phospho-p53, p21, total caspase 3 and cleaved caspase 3 in <span class="hlt">radiation</span> resistant cells and the <span class="hlt">radiation</span> susceptible (parent) line were compared, all of which were found to be similar. These patterns held true after analysis of p53 overexpression in H460 cells; however, H1299 cells transfected with mutant p53 did not express p21, whereas those given WT p53 produced a significant amount, as expected. A luciferase assay demonstrated the inability of mutant p53 to bind its consensus elements. An MTS assay using H460 and H1299 cells transfected with WT or mutant p53 showed that the novel mutation did not improve cell survival. In summary, functional characterization of a <span class="hlt">radiation-induced</span> p53 mutation in the H460 lung cancer cell line does not implicate it in the development of <span class="hlt">radiation</span> resistance.</p> <div class="credits"> <p class="dwt_author">Sun, Yunguang; Myers, Carey Jeanne; Dicker, Adam Paul; Lu, Bo</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">379</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008PhRvL.100m6101C"> <span id="translatedtitle"><span class="hlt">Crystalline</span> Amorphous Semiconductor Superlattice</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">A new class of superlattice, <span class="hlt">crystalline</span> amorphous superlattice (CASL), by alternatively depositing two semiconductor materials, is proposed. CASL displays three states depending on the component materials’ phase: both polycrystalline phases, both amorphous phases, and one polycrystalline phase while another amorphous phase. Using materials capable of reversible phase transition, CASL can demonstrate reversibility among three states. GeTe/Sb2Te3 CASL has been synthesized and proved by x-ray reflectometry and TEM results. The reversible transition among three states <span class="hlt">induced</span> by electrical and laser pulse was observed. The changes in the optical absorption edge, electrical resistivity, thermal conductivity, and crystallization temperature as a function of layer thickness are interpreted as quantum or nanoeffects. The unique properties of CASL enable the design of materials with specific properties.</p> <div class="credits"> <p class="dwt_author">Chong, T. C.; Shi, L. P.; Wei, X. Q.; Zhao, R.; Lee, H. K.; Yang, P.; Du, A. Y.</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">380</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20040087533&hterms=E-cadherin&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3D%2522E-cadherin%2522"> <span id="translatedtitle">Ionizing <span class="hlt">radiation</span> <span class="hlt">induces</span> heritable disruption of epithelial cell interactions</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Ionizing <span class="hlt">radiation</span> (IR) is a known human breast carcinogen. Although the mutagenic capacity of IR is widely acknowledged as the basis for its action as a carcinogen, we and others have shown that IR can also <span class="hlt">induce</span> growth factors and extracellular matrix remodeling. As a consequence, we have proposed that an additional factor contributing to IR carcinogenesis is the potential disruption of critical constraints that are imposed by normal cell interactions. To test this hypothesis, we asked whether IR affected the ability of nonmalignant human mammary epithelial cells (HMEC) to undergo tissue-specific morphogenesis in culture by using confocal microscopy and imaging bioinformatics. We found that irradiated single HMEC gave rise to colonies exhibiting decreased localization of E-cadherin, beta-catenin, and connexin-43, proteins necessary for the establishment of polarity and communication. Severely compromised acinar organization was manifested by the majority of irradiated HMEC progeny as quantified by image analysis. Disrupted cell-cell communication, aberrant cell-extracellular matrix interactions, and loss of tissue-specific architecture observed in the daughters of irradiated HMEC are characteristic of neoplastic progression. These data point to a heritable, nonmutational mechanism whereby IR compromises cell polarity and multicellular organization.</p> <div class="credits"> <p class="dwt_author">Park, Catherine C.; Henshall-Powell, Rhonda L.; Erickson, Anna C.; Talhouk, Rabih; Parvin, Bahram; Bissell, Mina J.; Barcellos-Hoff, Mary Helen; Chatterjee, A. (Principal Investigator)</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_18");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' href="#">4</a> <a onClick='return showDiv("page_5");' href="#">5</a> <a onClick='return showDiv("page_6");' href="#">6</a> <a onClick='return showDiv("page_7");' href="#">7</a> <a onClick='return showDiv("page_8");' href="#">8</a> <a onClick='return showDiv("page_9");' href="#">9</a> <a onClick='return showDiv("page_10");' href="#">10</a> <a onClick='return showDiv("page_11");' href="#">11</a> <a onClick='return showDiv("page_12");' href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a onClick='return showDiv("page_18");' href="#">18</a> <a style="font-weight: bold;">19</a> <a onClick='return showDiv("page_20");' href="#">20</a> <a onClick='return showDiv("page_21");' href="#">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_20");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> </div><!-- page_19 div --> <div id="page_20" class="hiddenDiv"> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_19");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' href="#">4</a> <a onClick='return showDiv("page_5");' href="#">5</a> <a onClick='return showDiv("page_6");' href="#">6</a> <a onClick='return showDiv("page_7");' href="#">7</a> <a onClick='return showDiv("page_8");' href="#">8</a> <a onClick='return showDiv("page_9");' href="#">9</a> <a onClick='return showDiv("page_10");' href="#">10</a> <a onClick='return showDiv("page_11");' href="#">11</a> <a onClick='return showDiv("page_12");' href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a onClick='return showDiv("page_18");' href="#">18</a> <a onClick='return showDiv("page_19");' href="#">19</a> <a style="font-weight: bold;">20</a> <a onClick='return showDiv("page_21");' href="#">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_21");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">381</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1985seit.nasa..571M"> <span id="translatedtitle">Investigations of <span class="hlt">radiation-induced</span> and carrier-enhanced conductivity</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">A steady-state carrier computer code, PECK (Parker Enhanced Carrier Kinetics), that predicts the <span class="hlt">radiation-induced</span> conductivity (RIC) produced in a dielectric by an electron beam was developed. The model, which assumes instantly-trapped holes, was then applied to experimental measurements on thin Kapton samples penetrated by an electron beam. Measurements at high bias were matched in the model by an appropriate choice for the trap-modulated electron mobility. A fractional split between front and rear currents measured at zone bias is explained on the basis of beam-scattering. The effects of carrier-enhanced conductivity (CEC) on data obtained for thick, free-surface Kapton samples is described by using an analytical model that incorporates field injection of carriers from the RIC region. The computer code, LWPCHARGE, modified for carrier transport, is also used to predict partial penetration effects associated with CEC in the unirradiated region. Experimental currents and surface voltages, when incorporated in the appropriate models, provide a value for the trap modulated mobility that is in essential agreement with the RIC results.</p> <div class="credits"> <p class="dwt_author">Meulenberg, A., Jr.; Parker, L. W.; Yadlowski, E. J.; Hazelton, R. C.</p> <p class="dwt_publisher"></p> <p class="publishDate">1985-03-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">382</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/21436110"> <span id="translatedtitle">Outcome of Carotid Artery Stenting for <span class="hlt">Radiation-Induced</span> Stenosis</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Purpose: Patients who have been irradiated at the neck have an increased risk of symptomatic stenosis of the carotid artery during follow-up. Carotid angioplasty and stenting (CAS) can be a preferable alternative treatment to carotid endarterectomy, which is associated with increased operative risks in these patients. Methods and Materials: We performed a prospective cohort study of 24 previously irradiated patients who underwent CAS for symptomatic carotid stenosis. We assessed periprocedural and nonprocedural events including transient ischemic attack (TIA), nondisabling stroke, disabling stoke, and death. Patency rates were evaluated on duplex ultrasound scans. Restenosis was defined as a stenosis of >50% at the stent location. Results: Periprocedural TIA rate was 8%, and periprocedural stroke (nondisabling) occurred in 4% of patients. After a mean follow-up of 3.3 years (range, 0.3-11.0 years), only one ipsilateral incident event (TIA) had occurred (4%). In 12% of patients, a contralateral incident event was present: one TIA (4%) and two strokes (12%, two disabling strokes). Restenosis was apparent in 17%, 33%, and 42% at 3, 12, and 24 months, respectively, although none of the patients with restenosed vessels became symptomatic. The length of the irradiation to CAS interval proved the only significant risk factor for restenosis. Conclusions: The results of CAS for <span class="hlt">radiation-induced</span> carotid stenosis are favorable in terms of recurrence of cerebrovascular events at the CAS site.</p> <div class="credits"> <p class="dwt_author">Dorresteijn, Lucille, E-mail: L.Dorresteijn@mst.n [Department of Neurology, Radboud University Nijmegen Medical Centre, Donders Institute for Brain, Cognition and Behaviour, Nijmegen (Netherlands); Vogels, Oscar [Department of Neurology and Clinical Neurophysiology, St Antonius Hospital, Nieuwegein (Netherlands); Leeuw, Frank-Erik de [Department of Neurology, Radboud University Nijmegen Medical Centre, Donders Institute for Brain, Cognition and Behaviour, Nijmegen (Netherlands); Vos, Jan-Albert [Department of Radiology, St Antonius Hospital, Nieuwegein (Netherlands); Christiaans, Marleen H. [Department of Neurology, Diakonessenhuis, Utrecht (Netherlands); Ackerstaff, Rob [Department of Neurology and Clinical Neurophysiology, St Antonius Hospital, Nieuwegein (Netherlands); Kappelle, Arnoud C. [Department of Neurology, Radboud University Nijmegen Medical Centre, Donders Institute for Brain, Cognition and Behaviour, Nijmegen (Netherlands)</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-08-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">383</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19850014204&hterms=flux+electric+conductivity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dflux%2Belectric%2Bconductivity"> <span id="translatedtitle">Investigations of <span class="hlt">radiation-induced</span> and carrier-enhanced conductivity</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">A steady-state carrier computer code, PECK (Parker Enhanced Carrier Kinetics), that predicts the <span class="hlt">radiation-induced</span> conductivity (RIC) produced in a dielectric by an electron beam was developed. The model, which assumes instantly-trapped holes, was then applied to experimental measurements on thin Kapton samples penetrated by an electron beam. Measurements at high bias were matched in the model by an appropriate choice for the trap-modulated electron mobility. A fractional split between front and rear currents measured at zone bias is explained on the basis of beam-scattering. The effects of carrier-enhanced conductivity (CEC) on data obtained for thick, free-surface Kapton samples is described by using an analytical model that incorporates field injection of carriers from the RIC region. The computer code, LWPCHARGE, modified for carrier transport, is also used to predict partial penetration effects associated with CEC in the unirradiated region. Experimental currents and surface voltages, when incorporated in the appropriate models, provide a value for the trap modulated mobility that is in essential agreement with the RIC results.</p> <div class="credits"> <p class="dwt_author">Meulenberg, A., Jr.; Parker, L. W.; Yadlowski, E. J.; Hazelton, R. C.</p> <p class="dwt_publisher"></p> <p class="publishDate">1985-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">384</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/24113311"> <span id="translatedtitle"><span class="hlt">Radiation-induced</span> vascular lesions of the skin: an overview.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary"><span class="hlt">Radiation-induced</span> cutaneous vascular neoplasms occur infrequently and comprise benign, so-called atypical vascular lesions (AVL) and angiosarcomas (AS), often being high-grade malignant tumors. Both arise most frequently within previously irradiated skin in breast-conserving-treated mammary cancer patients. Because of the different clinical course and, consequently, different therapeutic approaches, histopathologic distinction of AVL and AS is essential but significant morphologic overlap has been documented. Furthermore, the coexistence of these lesions or progression of AVL into AS has rarely been reported. Whether AVL is a precursor of AS is much debated and unresolved to date. Recent interest has focused on genetic changes and their differences in AS and AVL. MYC amplification and expression of the corresponding protein has been identified in AS in comparison with AVL. Therefore, MYC fluorescent in situ hybridization and anti-MYC immunohistochemical analysis are diagnostically useful in difficult cases. Furthermore, advanced tailored treatment strategies in AS, one of the most aggressive type of sarcoma, rely on identifying genes and proteins involved in malignant angiogenesis. PMID:24113311</p> <div class="credits"> <p class="dwt_author">Flucke, Uta; Requena, Luis; Mentzel, Thomas</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-11-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">385</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3316927"> <span id="translatedtitle"><span class="hlt">Radiation-Induced</span> Sarcoma of the Breast: A Systematic Review</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Introduction. <span class="hlt">Radiation-induced</span> sarcoma (RIS) is a rare, aggressive malignancy. Breast cancer survivors treated with radiotherapy constitute a large fraction of RIS patients. To evaluate evidenced-based practices for RIS treatment, we performed a systematic review of the published English-language literature. Methods. We performed a systematic keyword search of PubMed for original research articles pertaining to RIS of the breast. We classified and evaluated the articles based on hierarchal levels of scientific evidence. Results. We identified 124 original articles available for analysis, which included 1,831 patients. No randomized controlled trials involving RIS patients were found. We present the best available evidence for the etiology, comparative biology to primary sarcoma, prognostic factors, and treatment options for RIS of the breast. Conclusion. Although the evidence to guide clinical practice is limited to single institutional cohort studies, registry studies, case–control studies, and case reports, we applied the available evidence to address clinically relevant questions related to best practice in patient management. Surgery with widely negative margins remains the primary treatment of RIS. Unfortunately, the role of adjuvant and neoadjuvant chemotherapy remains uncertain. This systematic review highlights the need for additional well-designed studies to inform the management of RIS.</p> <div class="credits"> <p class="dwt_author">Sheth, Grishma R.; Cranmer, Lee D.; Smith, Benjamin D.; Grasso-LeBeau, Lauren</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">386</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/5179203"> <span id="translatedtitle">Early corticosteroid administration in experimental <span class="hlt">radiation-induced</span> heart disease</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The ability of dexamethasone (DEX) to reduce the severity of the late stage of <span class="hlt">radiation-induced</span> heart disease (RIHD) was assessed in 25 New Zealand white rabbits. Ten rabbits served as unirradiated controls (CONT). In Group A, seven rabbits received intravenous DEX prior to irradiation and every 24 hours for three consecutive days. DEX was not administered to the eight rabbits in Group B. At 100 days postirradiation, the severity of the late state was determined by microscopic examination (MICRO) for myocardial fibrosis and determination of myocardial hydroxyproline content (MHP). Myocardial fibrosis was evident in groups A (40%) and B (80%) while none was present in CONT by MICRO. One rabbit in Group B with no fibrosis by MICRO had abnormally increased MHP. MHP was significantly increased in Groups A and B, as compared to CONT (p < 0.01). In addition to less fibrosis by MICRO, Group A demonstrated a significant reduction of MHP when compared to Group B (p < 0.05). Determination of MHP may be superior to MICRO in the detection of the late stage of RIHD. Also, early DEX administration appears to reduce myocardial collagen content (fibrosis) in this experimental model.</p> <div class="credits"> <p class="dwt_author">Reeves, W.C.; Stryker, J.A.; Abt, A.A.; Chung, C.K.; Whitesell, L.; Zelis, R.</p> <p class="dwt_publisher"></p> <p class="publishDate">1980-02-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">387</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/5099910"> <span id="translatedtitle">Does oxygen enhance the <span class="hlt">radiation-induced</span> inactivation of penicillinase</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The <span class="hlt">radiation-induced</span> inactivation of penicillinase (..beta..-lactamase, EC 3.5.2.6) in dilute aqueous solutions buffered with phosphate was studied by examining enzyme radiosensitivity in the presence of various gases (He, O/sub 2/, H/sub 2/, N/sub 2/O and N/sub 2/O + O/sub 2/). The introduction of either N/sub 2/O or O/sub 2/ was found to reduce the radiodamage. On the other hand, H/sub 2/ or N/sub 2/O + O/sub 2/ gas mixture enhanced the radiosensitivity. In the presence of formate and oxygen no enzyme inactivation was detected. The results indicated that the specific damaging efficiency of H atoms is more than twofold higher than that of OH radicals; therefore, in 50 mM phosphate buffer, where more than half the free radicals are H atoms, the H radicals are responsible for the majority of the damage. The superoxide radicals appeared to be completely inactive and did not contribute to enzyme inactivation. Oxygen affected the radiosensitivity in two ways: (1) it protected by converting e/sub aq//sup -/ and H into harmless O/sub 2/-radicals; and (2) it increased inactivation by enhancing the damage brought about by OH radicals (OER = 2.6). In oxygenated buffer the protection effect of oxygen exceeded that of sensitization, thus giving rise to a moderate overall protection effect.</p> <div class="credits"> <p class="dwt_author">Samuni, A.; Kalkstein, A.; Czapski, G.</p> <p class="dwt_publisher"></p> <p class="publishDate">1980-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">388</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/24956797"> <span id="translatedtitle"><span class="hlt">Radiation-induced</span> removal of sulphadiazine antibiotics from wastewater.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The <span class="hlt">radiation-induced</span> removal of sulphadiazine (SD) belonging to the heterocyclic sulphonamides pharmaceuticals was investigated by gamma irradiation at different conditions in laboratory scale. The influence of initial SD concentrations, pH values, 02 and N2 on SD degradation was determined. The experimental results showed that gamma-ray irradiation was efficient for removing SD from wastewater. SD could be completely removed at an absorbed dose of 10 kGy. The degradation kinetics of SD conformed to the first-order kinetic equation. When SD concentration was in the range of 10-30 mg/L, the dose constant (d) decreased with an increasing initial SD concentration. The mineralization of SD, in terms of total organic carbon removal, was not obvious at a low absorbed dose, but it increased to more than 75% at 100 kGy. The biodegradability of SD was improved after irradiation, suggesting that irradiation could be used as a pretreatment technology for treating SD-containing wastewater. The possible degradation pathway of SD was tentatively proposed based on the analysis of intermediate products during gamma irradiation. PMID:24956797</p> <div class="credits"> <p class="dwt_author">Liu, Yuankun; Hu, Jun; Wang, Jianlong</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-08-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">389</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/30546285"> <span id="translatedtitle">HYPERBARIC OXYGEN THERAPY FOR <span class="hlt">RADIATION</span> <span class="hlt">INDUCED</span> HEMORRHAGIC CYSTITIS</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Purpose<span class="hlt">Radiation</span> therapy has been used successfully to treat pelvic malignancy but morbidity from hemorrhagic cystitis remains a major long-term sequela in 1 to 2% of patients. Obliterative endarteritis secondary to ionizing <span class="hlt">radiation</span> leads to tissue hypoxia and poor healing. Hyperbaric oxygen therapy has been demonstrated to improve angiogenesis and promote healing in <span class="hlt">radiation</span> injured tissue, including the bladder. We describe</p> <div class="credits"> <p class="dwt_author">RANJIV MATHEWS; NATARAJAN RAJAN; LAURA JOSEFSON; ENRICO CAMPORESI; ZAHI MAKHULI</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">390</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/41103602"> <span id="translatedtitle">Opportunities for nutritional amelioration of <span class="hlt">radiation-induced</span> cellular damage</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The closed environment and limited evasive capabilities inherent in space flight cause astronauts to be exposed to many potential harmful agents (chemical contaminants in the environment and cosmic <span class="hlt">radiation</span> exposure). Current power systems used to achieve space flight are prohibitively expensive for supporting the weight requirements to fully shield astronauts from cosmic <span class="hlt">radiation</span>. Therefore, <span class="hlt">radiation</span> poses a major, currently unresolvable</p> <div class="credits"> <p class="dwt_author">Nancy D Turner; Leslie A Braby; John Ford; Joanne R Lupton</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">391</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/24583639"> <span id="translatedtitle">Low-dose <span class="hlt">radiation</span> exposure <span class="hlt">induces</span> a HIF-1-mediated adaptive and protective metabolic response.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Because of insufficient understanding of the molecular effects of low levels of <span class="hlt">radiation</span> exposure, there is a great uncertainty regarding its health risks. We report here that treatment of normal human cells with low-dose <span class="hlt">radiation</span> <span class="hlt">induces</span> a metabolic shift from oxidative phosphorylation to aerobic glycolysis resulting in increased <span class="hlt">radiation</span> resistance. This metabolic change is highlighted by upregulation of genes encoding glucose transporters and enzymes of glycolysis and the oxidative pentose phosphate pathway, concomitant with downregulation of mitochondrial genes, with corresponding changes in metabolic flux through these pathways. Mechanistically, the metabolic reprogramming depends on HIF1?, which is <span class="hlt">induced</span> specifically by low-dose irradiation linking the metabolic pathway with cellular <span class="hlt">radiation</span> dose response. Increased glucose flux and <span class="hlt">radiation</span> resistance from low-dose irradiation are also observed systemically in mice. This highly sensitive metabolic response to low-dose <span class="hlt">radiation</span> has important implications in understanding and assessing the health risks of <span class="hlt">radiation</span> exposure. PMID:24583639</p> <div class="credits"> <p class="dwt_author">Lall, R; Ganapathy, S; Yang, M; Xiao, S; Xu, T; Su, H; Shadfan, M; Asara, J M; Ha, C S; Ben-Sahra, I; Manning, B D; Little, J B; Yuan, Z-M</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">392</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/6302440"> <span id="translatedtitle"><span class="hlt">Radiation</span> <span class="hlt">induced</span> failures of complementary metal oxide semiconductor containing pacemakers: a potentially lethal complication</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">New multi-programmable pacemakers frequently employ complementary metal oxide semiconductors (CMOS). This circuitry appears more sensitive to the effects of ionizing <span class="hlt">radiation</span> when compared to the semiconductor circuits used in older pacemakers. A case of <span class="hlt">radiation</span> <span class="hlt">induced</span> runaway pacemaker in a CMOS device is described. Because of this and other recent reports of <span class="hlt">radiation</span> therapy-<span class="hlt">induced</span> CMOS type pacemaker failure, these pacemakers should not be irradiated. If necessary, the pacemaker can be shielded or moved to a site which can be shielded before institution of <span class="hlt">radiation</span> therapy. This is done to prevent damage to the CMOS circuit and the life threatening arrythmias which may result from such damage.</p> <div class="credits"> <p class="dwt_author">Lewin, A.A.; Serago, C.F.; Schwade, J.G.; Abitbol, A.A.; Margolis, S.C.</p> <p class="dwt_publisher"></p> <p class="publishDate">1984-10-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">393</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/14711370"> <span id="translatedtitle">Effect of dicarbonyl-<span class="hlt">induced</span> browning on alpha-<span class="hlt">crystallin</span> chaperone-like activity: physiological significance and caveats of in vitro aggregation assays.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Alpha-<span class="hlt">crystallin</span> is a member of the small heat-shock protein family and functions like a molecular chaperone, and may thus help in maintaining the transparency of the eye lens by protecting the lens proteins from various stress conditions. Non-enzymic glycation of long-lived proteins has been implicated in several age- and diabetes-related complications, including cataract. Dicarbonyl compounds such as methylglyoxal and glyoxal have been identified as the predominant source for the formation of advanced glycation end-products in various tissues including the lens. We have investigated the effect of non-enzymic browning of alpha-<span class="hlt">crystallin</span> by reactive dicarbonyls on its molecular chaperone-like function. Non-enzymic browning of bovine alpha-<span class="hlt">crystallin</span> in vitro caused, along with altered secondary and tertiary structures, cross-linking and high-molecular-mass aggregation. Notwithstanding these structural changes, methylglyoxal- and glyoxal-modified alpha-<span class="hlt">crystallin</span> showed enhanced anti-aggregation activity in various in vitro aggregation assays. Paradoxically, increased chaperone-like activity of modified alpha-<span class="hlt">crystallin</span> was not associated with increased surface hydrophobicity and rather showed less 8-anilinonaphthalene-l-sulphonic acid binding. In contrast, the chaperone-like function of modified alpha-<span class="hlt">crystallin</span> was found to be reduced in assays that monitor the prevention of enzyme inactivation by UV-B and heat. Moreover, incubation of bovine lens with methylglyoxal in organ culture resulted in cataract formation with accumulation of advanced glycation end-products and recovery of alpha-<span class="hlt">crystallin</span> in high proportions in the insoluble fraction. Furthermore, soluble alpha-<span class="hlt">crystallin</span> from methylglyoxal-treated lenses showed decreased chaperone-like activity. Thus, in addition to describing the effects of methylglyoxal and glyoxal on structure and chaperone-like activity, our studies also bring out an important caveat of aggregation assays in the context of the chaperone function of alpha-<span class="hlt">crystallin</span>. PMID:14711370</p> <div class="credits"> <p class="dwt_author">Kumar, M Satish; Reddy, P Yadagiri; Kumar, P Anil; Surolia, Ira; Reddy, G Bhanuprakash</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-04-15</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">394</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2006QuEle..36..369K"> <span id="translatedtitle">INTERACTION OF LASER <span class="hlt">RADIATION</span> WITH MATTER: Resonance laser-<span class="hlt">induced</span> ionisation of sodium vapour taking <span class="hlt">radiative</span> transfer into account</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The problem of ionisation of atomic sodium in the field of resonance laser <span class="hlt">radiation</span> is numerically solved taking <span class="hlt">radiative</span> transfer into account. Seed electrons are produced due to the mechanism of associative ionisation, then they gain energy in superelastic processes (collisions of the second kind) and initiate the avalanche ionisation of the medium by electron impact. We studied the effect of secondary <span class="hlt">radiation</span> on the laser pulse propagation upon competition between the ionising and quenching electron collisions with excited atoms, on the kinetics of ionisation-<span class="hlt">induced</span> vapour bleaching, and the plasma channel expansion in the form of a halo.</p> <div class="credits"> <p class="dwt_author">Kosarev, N. I.; Shaparev, N. Ya</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">395</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20040087647&hterms=genome&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dgenome"> <span id="translatedtitle"><span class="hlt">Radiation-induced</span> gene expression in the nematode Caenorhabditis elegans</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">We used the nematode C. elegans to characterize the genotoxic and cytotoxic effects of ionizing <span class="hlt">radiation</span> in a simple animal model emphasizing the unique effects of charged particle <span class="hlt">radiation</span>. Here we demonstrate by RT-PCR differential display and whole genome microarray hybridization experiments that gamma rays, accelerated protons and iron ions at the same physical dose lead to unique transcription profiles. 599 of 17871 genes analyzed (3.4%) showed differential expression 3 hrs after exposure to 3 Gy of <span class="hlt">radiation</span>. 193 were up-regulated, 406 were down-regulated and 90% were affected only by a single species of <span class="hlt">radiation</span>. A novel statistical clustering technique identified the regulatory relationships between the <span class="hlt">radiation</span>-modulated genes and showed that genes affected by each <span class="hlt">radiation</span> species were associated with unique regulatory clusters. This suggests that independent homeostatic mechanisms are activated in response to <span class="hlt">radiation</span> exposure as a function of track structure or ionization density.</p> <div class="credits"> <p class="dwt_author">Nelson, Gregory A.; Jones, Tamako A.; Chesnut, Aaron; Smith, Anna L.</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">396</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3974334"> <span id="translatedtitle">Harmonic Tracking of Acoustic <span class="hlt">Radiation</span> Force <span class="hlt">Induced</span> Displacements</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Ultrasound-based elasticity imaging methods rely upon accurate estimates of tissue deformation to characterize the mechanical properties of soft tissues. These methods are corrupted by clutter, which can bias and/or increase variance in displacement estimates. Harmonic imaging methods are routinely used for clutter suppression and improved image quality in conventional B-mode ultrasound, but have not been utilized in ultrasound-based elasticity imaging methods. We introduce a novel, fully-sampled pulse inversion harmonic method for tracking tissue displacements that corrects the loss in temporal sampling frequency associated with conventional pulse inversion techniques. The method is implemented with Acoustic <span class="hlt">Radiation</span> Force Impulse (ARFI) imaging to monitor the displacements <span class="hlt">induced</span> by an impulsive acoustic <span class="hlt">radiation</span> force excitation. Custom pulse sequences were implemented on a diagnostic ultrasound scanner to collect spatially-matched fundamental and harmonic information within a single acquisition. B-mode and ARFI images created from fundamental data collected at 4 MHz and 8 MHz are compared with 8 MHz harmonic images created using a bandpass filter approach and the fully sampled pulse inversion method. In homogeneous, tissue-mimicking phantoms, where no visible clutter was observed, there was little difference in the axial displacements, estimated jitter, and normalized cross-correlation among the fundamental and harmonic tracking methods. The similarity of the lower and higher frequency methods suggests that any improvement due to the increased frequency of the harmonic components is negligible. The harmonic tracking methods demonstrated a marked improvement in B-mode and ARFI image quality of in vivo carotid arteries. Improved feature detection and decreased variance in estimated displacements were observed in the arterial walls of harmonic ARFI images, especially in the pulse inversion harmonic ARFI images. Within the lumen, the harmonic tracking methods improved the discrimination of the blood–vessel interface, making it easier to visualize plaque boundaries. Improvements in harmonic ARFI images in vivo were consistent with suppressed clutter supported by improved contrast and CNR in the matched harmonic B-mode images compared to the fundamental B-mode images. These results suggest that harmonic tracking methods can improve the clinical utility and diagnostic accuracy of ultrasound-based elasticity imaging methods.</p> <div class="credits"> <p class="dwt_author">Doherty, Joshua R.; Dahl, Jeremy J.; Trahey, Gregg E.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">397</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012RaPC...81..599S"> <span id="translatedtitle">Characteristics of <span class="hlt">radiation</span> <span class="hlt">induced</span> light in optical fibres for portal imaging application</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The purpose of this paper is to characterize the <span class="hlt">radiation</span> <span class="hlt">induced</span> light in optical fibres to optimise the design of a new Cherenkov detector for portal imaging application in <span class="hlt">radiation</span> therapy. Experiments were performed using a single optical fibre to evaluate the angle dependence, spectrum and temporal properties of the <span class="hlt">radiation</span> <span class="hlt">induced</span> light in the optical fibre in comparison with that of Cherenkov <span class="hlt">radiation</span>. A theoretical model was also developed to compare with experiments. It has been found that <span class="hlt">radiation-induced</span> light output from the optical fibre under megavoltage (MV) x-ray irradiation is significantly (about 45 times) higher than that under 100 kVp x-ray irradiation for the same dose rate at the fibre. The angular-dependence, spectrum and temporal properties of the <span class="hlt">radiation</span> <span class="hlt">induced</span> light in the optical fibre under MV x-ray irradiation match that of Cherenkov <span class="hlt">radiation</span>. Different angular dependence and spectrum results from that of previous studies on <span class="hlt">radiation</span> <span class="hlt">induced</span> light in optical fibres have also been found. The result of the theoretical model agrees with the angle-dependence measurements.</p> <div class="credits"> <p class="dwt_author">Silva, I.; Pang, G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">398</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/1597954"> <span id="translatedtitle">Response of advanced bipolar processes to ionizing <span class="hlt">radiation</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Ionizing <span class="hlt">radiation</span> <span class="hlt">induced</span> gain degradation in microcircuit bipolar polysilicon and <span class="hlt">crystalline</span> emitter transistors is investigated. In this work, 60Co irradiation testing was performed on bipolar test structures. The effects of collector bias, dose rate, and anneal temperature are discussed. Major differences in the <span class="hlt">radiation</span> response of polysilicon emitter transistors are demonstrated as a function of dose rate. The worst-case gain</p> <div class="credits"> <p class="dwt_author">Edward W. Enlow; Ronald L. Pease; William Combs; Ron D. Schrimpf; R. Nathan Nowlin</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">399</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/770807"> <span id="translatedtitle">Synchrotron-<span class="hlt">Radiation</span> <span class="hlt">Induced</span> X-Ray Emission (SRIXE)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Elemental analysis using emission of characteristic x rays is a well-established scientific method. The success of this analytical method is highly dependent on the properties of the source used to produce the x rays. X-ray tubes have long existed as a principal excitation source, but electron and proton beams have also been employed extensively. The development of the synchrotron <span class="hlt">radiation</span> x-ray source that has taken place during the past 40 years has had a major impact on the general field of x-ray analysis. Even tier 40 years, science of x-ray analysis with synchrotron x-ray beams is by no means mature. Improvements being made to existing synchrotron facilities and the design and construction of new facilities promise to accelerate the development of the general scientific use of synchrotron x-ray sources for at least the next ten years. The effective use of the synchrotron source technology depends heavily on the use of high-performance computers for analysis and theoretical interpretation of the experimental data. Fortunately, computer technology has advanced at least as rapidly as the x-ray technology during the past 40 years and should continue to do so during the next decade. The combination of these technologies should bring about dramatic advances in many fields where synchrotron x-ray science is applied. It is interesting also to compare the growth and rate of acceptance of this particular research endeavor to the rates for other technological endeavors. Griibler [1997] cataloged the time required for introduction, diffusion,and acceptance of technological, economic, and social change and found mean values of 40 to 50 years. The introduction of the synchrotron source depends on both technical and non-technical factors, and the time scale at which this seems to be occurring is quite compatible with what is seen for other major innovations such as the railroad or the telegraph. It will be interesting to see how long the present rate of technological change and increase in scientific use can be maintained for the synchrotron x-ray source. A short summary of the present state of the synchrotron <span class="hlt">radiation-induced</span> x-ray emission (SRIXE) method is presented here. Basically, SRIXE experiments can include any that depend on the detection. of characteristic x-rays produced by the incident x-ray beam born the synchrotron source as they interact with a sample. Thus, experiments done to measure elemental composition, chemical state, crystal, structure, and other sample parameters can be considered in a discussion of SRIXE. It is also clear that the experimentalist may well wish to use a variety of complementary techniques for study of a given sample. For this reason, discussion of computed microtomography (CMT) and x-ray diffraction is included here. It is hoped that this present discussion will serve as a succinct introduction to the basic ideas of SRIXE for those not working in the field and possibly help to stimulate new types of work by those starting in the field as well as by experienced practitioners of the art. The topics covered include short descriptions of (1) the properties of synchrotron <span class="hlt">radiation</span>, (2) a description of facilities used for its production, (3) collimated microprobe, (4) focused microprobes, (5) continuum and monoenergetic excitation, (6) detection limits, (7) quantitation, (8) applications of SRIXE, (9) computed microtomography (CMT), and (10)chemical speciation using x-ray absorption near-edge structure (XANES) and extended x-ray absorption fine structure (EXAFS). An effort has been made to cite a wide variety of work from different laboratories to show the vital nature of the field.</p> <div class="credits"> <p class="dwt_author">Jones, Keith W.</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-09-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">400</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/15139986"> <span id="translatedtitle">alphaB-<span class="hlt">Crystallin</span> is a Small Heat Shock Protein</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Sequence similarity between alpha B-<span class="hlt">crystallin</span> and small heat shock proteins (HSPs) has prompted us to investigate whether alphaB-<span class="hlt">crystallin</span> expression is <span class="hlt">induced</span> by heat shock. Indeed, accumulation of alphaB-<span class="hlt">crystallin</span> was detected immunologically in NIH 3T3 cells after incubation at elevated temperatures and after addition of Cd2+ or sodium arsenite to these cells. Two-dimensional gel electrophoresis revealed identity between alphaB-<span class="hlt">crystallin</span> from eye</p> <div class="credits"> <p class="dwt_author">Roman Klemenz; Erika Frohli; Rudolf H. Steiger; Reinhold Schafer; Akira Aoyama</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_19");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' href="#">4</a> <a onClick='return showDiv("page_5");' href="#">5</a> <a onClick='return showDiv("page_6");' href="#">6</a> <a onClick='return showDiv("page_7");' href="#">7</a> <a onClick='return showDiv("page_8");' href="#">8</a> <a onClick='return showDiv("page_9");' href="#">9</a> <a onClick='return showDiv("page_10");' href="#">10</a> <a onClick='return showDiv("page_11");' href="#">11</a> <a onClick='return showDiv("page_12");' href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a onClick='return showDiv("page_18");' href="#">18</a> <a onClick='return showDiv("page_19");' href="#">19</a> <a style="font-weight: bold;">20</a> <a onClick='return showDiv("page_21");' href="#">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_21");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> </div><!-- page_20 div --> <div id="page_21" class="hiddenDiv"> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_20");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' href="#">4</a> <a onClick='return showDiv("page_5");' href="#">5</a> <a onClick='return showDiv("page_6");' href="#">6</a> <a onClick='return showDiv("page_7");' href="#">7</a> <a onClick='return showDiv("page_8");' href="#">8</a> <a onClick='return showDiv("page_9");' href="#">9</a> <a onClick='return showDiv("page_10");' href="#">10</a> <a onClick='return showDiv("page_11");' href="#">11</a> <a onClick='return showDiv("page_12");' href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a onClick='return showDiv("page_18");' href="#">18</a> <a onClick='return showDiv("page_19");' href="#">19</a> <a onClick='return showDiv("page_20");' href="#">20</a> <a style="font-weight: bold;">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_22");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">401</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/5757658"> <span id="translatedtitle">Ultraviolet <span class="hlt">radiation</span> directly <span class="hlt">induces</span> pigment production by cultured human melanocytes</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">In humans the major stimulus for cutaneous pigmentation is ultraviolet <span class="hlt">radiation</span> (UVR). Little is known about the mechanism underlying this response, in part because of the complexity of interactions in whole epidermis. Using a recently developed culture system, human melanocytes were exposed daily to a physiologic range of UVR doses from a solar simulator. Responses were determined 24 hours after the last exposure. There was a dose-related increase in melanin content per cell and uptake of /sup 14/C-DOPA, accompanied by growth inhibition. Cells from donors of different racial origin gave proportionately similar increases in melanin, although there were approximately tenfold differences in basal values. Light and electron microscopy revealed UVR-stimulated increases in dendricity as well as melanosome number and degree of melanization, analogous to the well-recognized melanocyte changes following sun exposure of intact skin. Similar responses were seen with Cloudman S91 melanoma cells, although this murine cell line required lower UVR dosages and fewer exposures for maximal stimulation. These data establish that UVR is capable of directly stimulating melanogenesis. Because cyclic AMP elevation has been associated in some settings with increased pigment production by cultured melanocytes, preliminary experiments were conducted to see if the effects of UVR were mediated by cAMP. Both alpha-MSH and isobutylmethylxanthine (IBMX), as positive controls, caused a fourfold increase in cAMP level in human melanocytes and/or S91 cells, but following a dose of UVR sufficient to stimulate pigment production there was no change in cAMP level up to 4 hours after exposure. Thus, it appears that the UVR-<span class="hlt">induced</span> melanogenesis is mediated by cAMP-independent mechanisms.</p> <div class="credits"> <p class="dwt_author">Friedmann, P.S.; Gilchrest, B.A.</p> <p class="dwt_publisher"></p> <p class="publishDate">1987-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">402</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1981RaPC...18..503K"> <span id="translatedtitle"><span class="hlt">Radiation-induced</span> grafting of acrylic acid onto polyethylene filaments</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary"><span class="hlt">Radiation-induced</span> grafting of acrylic acid onto high density polyethylene (PE) filaments was carried out in order to raise softening temperature and impart flame retardance and hydrophilic properties. Mutual ?-irradiation method was employed for the grafting in a mixture of acrylic acid (AA), ethylene dichloride and water containing a small amount of ferrous ammonium sulfate. The rate of grafting was very low at room temperature. On the other hand, large percent grafts were obtained when the grafting was performed at an elevated temperature. Activation energy for the initial rate of grafting was found to be 17 {kcal}/{mol} between 20 and 60°C and 10 {kcal}/{mol} between 60 and 80°C. Original PE filament begins to shrink at 70°C, show maximum shrinkage of 50% at 130°C and then breaks off at 136°C. When a 34% AA graft is converted to metallic salt such as sodium and calcium, the graft filament retains its filament form even above 300°C and gives maximum shrinkage of 15%. Burning tests by a wire-netting basket method indicate that graft filaments and its metallic salts do not form melting drops upon burning and are self-extinguishing. Original PE filament shows no moisture absorption, however, that of AA-grafted PE increases with increasing graft percent. The sodium salt of 15% graft shows the same level of moisture regain as cotton. The AA-grafted PE filament and its metallic salts can be dyed with cationic dyes even at 1% graft. Tensile properties of PE filament is impaired neither by grafting nor by conversion to metallic salts.</p> <div class="credits"> <p class="dwt_author">Kaji, K.; Okada, T.; Sakurada, I.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">403</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014PhRvB..89x5434Z"> <span id="translatedtitle">Tunable terahertz <span class="hlt">radiation</span> from graphene <span class="hlt">induced</span> by moving electrons</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Based on a structure consisting of a single graphene layer situated on periodic dielectric gratings, we show theoretically that terahertz <span class="hlt">radiation</span> can be generated by low-energy electron bunches moving atop the graphene layer. The THz emission arises from graphene plasmons excited efficiently by the moving electrons. We find that the <span class="hlt">radiation</span> intensity can be strongly enhanced due to the local field enhancement of graphene plasmons arising from their low losses and high confinement. Importantly, the <span class="hlt">radiation</span> frequency can be tuned over a wide spectral range by varying the Fermi level of the graphene layer. Our results could find applications in developing tunable and miniature free-electron terahertz <span class="hlt">radiation</span> sources.</p> <div class="credits"> <p class="dwt_author">Zhan, Tianrong; Han, Dezhuan; Hu, Xinhua; Liu, Xiaohan; Chui, Siu-Tat; Zi, Jian</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">404</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/5099556"> <span id="translatedtitle">Mechanisms of <span class="hlt">radiation-induced</span> skeletal cancer: Cells at risk and cell-specific <span class="hlt">radiation</span> dosimetry</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Progress occurred in several areas. The activation of bone remodeling occurred before day 3 and the reversal phase occurred before day 14 of lactation and low calcium diet. These findings will enable us to better design future cell kinetics studies. A semi-automatic quantitative neutron-<span class="hlt">induced</span> autoradiography system for bone sections containing plutonium-239 was developed and deployed. The same bone sections will be analyzed by dynamic histomorphometry. The system will generate much needed distribution values for cancellous and cortical boned and formic and resting surfaces needed in our calculations of cell-specific <span class="hlt">radiation</span> dosimetry. The bone formation rate for 4 cortical bone sites was found to be less than 1%/yr. The rib was slightly higher at 5%/yr. These values were at least 30 times lower than those observed in various cancellous bone sites in the same animals. The long residence time of bone surface cells could partially explain the occurrence of cortical bone tumors in dogs administered alpha-emitting bone-seeking radionuclides. 2 tabs.</p> <div class="credits"> <p class="dwt_author">Jee, W.S.S.</p> <p class="dwt_publisher"></p> <p class="publishDate">1989-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">405</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3427298"> <span id="translatedtitle">Exposure to Heavy Ion <span class="hlt">Radiation</span> <span class="hlt">Induces</span> Persistent Oxidative Stress in Mouse Intestine</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Ionizing <span class="hlt">radiation-induced</span> oxidative stress is attributed to generation of reactive oxygen species (ROS) due to radiolysis of water molecules and is short lived. Persistent oxidative stress has also been observed after <span class="hlt">radiation</span> exposure and is implicated in the late effects of <span class="hlt">radiation</span>. The goal of this study was to determine if long-term oxidative stress in freshly isolated mouse intestinal epithelial cells (IEC) is dependent on <span class="hlt">radiation</span> quality at a dose relevant to fractionated radiotherapy. Mice (C57BL/6J; 6 to 8 weeks; female) were irradiated with 2 Gy of ?-rays, a low-linear energy transfer (LET) <span class="hlt">radiation</span>, and intestinal tissues and IEC were collected 1 year after <span class="hlt">radiation</span> exposure. Intracellular ROS, mitochondrial function, and antioxidant activity in IEC were studied by flow cytometry and biochemical assays. Oxidative DNA damage, cell death, and mitogenic activity in IEC were assessed by immunohistochemistry. Effects of ? <span class="hlt">radiation</span> were compared to 56Fe <span class="hlt">radiation</span> (iso-toxic dose: 1.6 Gy; energy: 1000 MeV/nucleon; LET: 148 keV/µm), we used as representative of high-LET <span class="hlt">radiation</span>, since it's one of the important sources of high Z and high energy (HZE) <span class="hlt">radiation</span> in cosmic rays. <span class="hlt">Radiation</span> quality affected the level of persistent oxidative stress with higher elevation of intracellular ROS and mitochondrial superoxide in high-LET 56Fe <span class="hlt">radiation</span> compared to unirradiated controls and ? <span class="hlt">radiation</span>. NADPH oxidase activity, mitochondrial membrane damage, and loss of mitochondrial membrane potential were greater in 56Fe-irradiated mice. Compared to ? <span class="hlt">radiation</span> oxidative DNA damage was higher, cell death ratio was unchanged, and mitotic activity was increased after 56Fe <span class="hlt">radiation</span>. Taken together our results indicate that long-term functional dysregulation of mitochondria and increased NADPH oxidase activity are major contributing factors towards heavy ion <span class="hlt">radiation-induced</span> persistent oxidative stress in IEC with potential for neoplastic transformation.</p> <div class="credits"> <p class="dwt_author">Datta, Kamal; Suman, Shubhankar; Kallakury, Bhaskar V. S.; Fornace, Albert J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">406</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=DE82021943"> <span id="translatedtitle"><span class="hlt">Radiation-Induced</span> Dimensional Changes of AM-350 Stainless Steel (LWBR Development Program).</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">AM-350 stainless steel, which is used for fuel rod support grids in the Light Water Breeder Reactor, experiences <span class="hlt">radiation-induced</span> dimensional changes during in-reactor service. Dimensional changes (strain) were measured periodically for two sets of test ...</p> <div class="credits"> <p class="dwt_author">B. C. Smith B. Z. Hyatt</p> <p class="dwt_publisher"></p> <p class="publishDate">1982-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">407</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=DE99618008"> <span id="translatedtitle">Electron paramagnetic resonance study on the ionizing <span class="hlt">radiation</span> <span class="hlt">induced</span> defects of the tooth enamel hydroxyapatite.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">Hydroxyapatite is the main constituent of calcified tissues. Defects <span class="hlt">induced</span> by ionizing <span class="hlt">radiations</span> in this biomineral can present high stability and then, these are used as biological markers in radiological accidents, irradiated food identifying and geo...</p> <div class="credits"> <p class="dwt_author">L. M. Oliveira</p> <p class="dwt_publisher"></p> <p class="publishDate">1995-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">408</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=DE2006891255"> <span id="translatedtitle">Mechanisms of Adaptive Responses and Genomic Instability <span class="hlt">Induced</span> by Low Dose/Low Dose Rate <span class="hlt">Radiation</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">The proposed study investigates the effect of low dose and low dose rate <span class="hlt">radiation</span> exposure (X-rays) on <span class="hlt">induced</span> genomic instability and the adaptive response, including the molecular mechanisms for these phenomena. The proposed studies will utilize human ...</p> <div class="credits"> <p class="dwt_author">W. F. Morgan</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">409</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=CONF7901253"> <span id="translatedtitle">Effects of <span class="hlt">Radiation-Induced</span> Segregation and Preferential Sputtering on the Sputtering Rate of Alloys.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">Changes in the surface composition and in the sputtering rate of binary alloys were calculated using a kinetic model that includes the effects of <span class="hlt">radiation-induced</span> segregation and preferential sputtering. Numerical solutions were obtained for two dilute N...</p> <div class="credits"> <p class="dwt_author">N. Q. Lam G. K. Leaf H. Wiedersich</p> <p class="dwt_publisher"></p> <p class="publishDate">1979-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">410</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=UR3490511"> <span id="translatedtitle">Renal and Adrenal Factors in <span class="hlt">Radiation-Induced</span> Hypertension and Nephrosclerosis.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">Experiments were conducted in order to investigate the effects of adrenalectomy on the incidence, severity, and rate of progression of <span class="hlt">radiation-induced</span> hypertension and nephrosclerosis in male rats. Adrenalectomized and non-adrenalectomized rats received...</p> <div class="credits"> <p class="dwt_author">A. G. Lurie</p> <p class="dwt_publisher"></p> <p class="publishDate">1973-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">411</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20040141559&hterms=hoff&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3D%2522hoff%2522"> <span id="translatedtitle">The potential influence of <span class="hlt">radiation-induced</span> microenvironments in neoplastic progression</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Ionizing <span class="hlt">radiation</span> is a complete carcinogen, able both to initiate and promote neoplastic progression and is a known carcinogen of human and murine mammary gland. Tissue response to <span class="hlt">radiation</span> is a composite of genetic damage, cell death and induction of new gene expression patterns. Although DNA damage is believed to initiate carcinogenesis, the contribution of these other aspects of <span class="hlt">radiation</span> response are beginning to be explored. Our studies demonstrate that <span class="hlt">radiation</span> elicits rapid and persistent global alterations in the mammary gland microenvironment. We postulate that <span class="hlt">radiation-induced</span> microenvironments may affect epithelial cells neoplastic transformation by altering their number or susceptibility. Alternatively, <span class="hlt">radiation</span> <span class="hlt">induced</span> microenvironments may exert a selective force on initiated cells and/or be conducive to progression. A key impetus for these studies is the possibility that blocking these events could be a strategy to interrupt neoplastic progression.</p> <div class="credits"> <p class="dwt_author">Barcellos-Hoff, M. H.; Chatterjee, A. (Principal Investigator)</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">412</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/21119289"> <span id="translatedtitle"><span class="hlt">Radiation-induced</span> chondrosarcomas: a case report with review of literature.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary"><span class="hlt">Radiation</span> therapy has become an important component of various cancer treatments. The development of second malignancy as a result of <span class="hlt">radiation</span> therapy is a well-known sinister complication. However, <span class="hlt">radiation-induced</span> sarcomas (RIS) are rare complications of <span class="hlt">radiation</span> therapy. The timescale between completion of the radiotherapy and the development of a second malignancy, known as the latent period, can vary widely from as little as 5 years to 50 years later. <span class="hlt">Radiation-induced</span> sarcomas per se are very rare and those with histomorphology of chondrosarcomas are even rarer. We report a rare case of RIS of left iliac bone in a 62-year-old lady after combined chemotherapy and external beam <span class="hlt">radiation</span> therapy for cervical carcinoma (stage IIb). This case is being reported for its extreme rarity, vivid histology and clinical presentation. PMID:21119289</p> <div class="credits"> <p class="dwt_author">Gupta, G; Hafiz, A; Gandhi, J S</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">413</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/39370928"> <span id="translatedtitle"><span class="hlt">Radiation-induced</span> amorphization resistance and <span class="hlt">radiation</span> tolerance in structurally related oxides</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Ceramics destined for use in hostile environments such as nuclear reactors or waste immobilization must be highly durable and especially resistant to <span class="hlt">radiation</span> damage effects. In particular, they must not be prone to amorphization or swelling. Few ceramics meet these criteria and much work has been devoted in recent years to identifying <span class="hlt">radiation</span>-tolerant ceramics and the characteristics that promote <span class="hlt">radiation</span></p> <div class="credits"> <p class="dwt_author">Kurt E. Sickafus; Robin W. Grimes; James A. Valdez; Antony Cleave; Ming Tang; Manabu Ishimaru; Siobhan M. Corish; Christopher R. Stanek; Blas P. Uberuaga</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">414</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2007RaPC...76..901K"> <span id="translatedtitle"><span class="hlt">Radiation-induced</span> grafting of vinyl benzyl trimethyl ammonium chloride onto nylon-6 fabric</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Vinyl benzyl trimethyl ammonium chloride (VBTAC) was grafted onto nylon-6 fabric in the presence of 2- hydroxy ethyl methacrylate (HEMA) by the simultaneous irradiation method in the presence of air with 60Co ?-<span class="hlt">radiations</span>. An increase in grafting was observed with increasing dose. Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA) confirmed the grafting of VBTAC. Morphological changes after grafting were confirmed by scanning electron microscopy (SEM). The X-ray diffraction (XRD) pattern showed changes in <span class="hlt">crystallinity</span> on grafting. The initial studies carried out with grafted nylon fabric showed behavioural changes in the burning properties.</p> <div class="credits"> <p class="dwt_author">Kolhe, Shailesh M.; Kumar, Ashok</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-05-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">415</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/30668156"> <span id="translatedtitle">Effects of Berberine Against <span class="hlt">Radiation-Induced</span> Intestinal Injury in Mice</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Purpose: <span class="hlt">Radiation-induced</span> intestinal injury is a significant clinical problem in patients undergoing abdominal radiotherapy (RT). Berberine has been used as an antimicrobial, anti-inflammatory, and antimotility agent. The present study investigated the protective effect of berberine against <span class="hlt">radiation-induced</span> intestinal injury. Methods and Materials: The mice were administrated berberine or distilled water. A total of 144 mice underwent 0, 3, 6, 12,</p> <div class="credits"> <p class="dwt_author">Guang-Hui Li; Ya-Ping Zhang; Jin-liang Tang; Zheng-Tang Chen; Yi-De Hu; Hong Wei; De-Zhi Li; Ping Hao; Dong-Lin Wang</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">416</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/54690298"> <span id="translatedtitle">Temperature and Doping Level Dependence of Delayed <span class="hlt">Radiation</span> <span class="hlt">Induced</span> Conductivity in Chromium Polyacrylate</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The <span class="hlt">radiation</span> <span class="hlt">induced</span> conductivity of post-irradiated chromium polyacrylate (CrPA) is investigated as a function of exposure rate, temperature, doping level (concentration) and field strength. The samples are irradiated with 5.5 MeV 241AM, alpha-source. The exposure rate is varied from 5.96×108 particles\\/cm2 to 3.58×109 particles\\/cm2. It is noted that the <span class="hlt">radiation</span> <span class="hlt">induced</span> conductivity in this material increases exponentially, passes through a</p> <div class="credits"> <p class="dwt_author">A. Rauf; S. U. Rehman; Farid A. Khwaja</p> <p class="dwt_publisher"></p> <p class="publishDate">1995-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">417</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.springerlink.com/index/rk05486q7153778j.pdf"> <span id="translatedtitle"><span class="hlt">Radiation-induced</span> adult medulloblastoma: a two-case report and review of the literature</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary"><span class="hlt">Radiation-induced</span> medulloblastoma is an exceedingly rare phenomenon for which treatment standards have not been established.\\u000a The literature suggests that these tumors are high grade with aggressive behavior. We report two cases of <span class="hlt">radiation-induced</span>\\u000a medulloblastoma which have been treated with full dose re-irradiation with curative intent. In both cases, treatment toxicity\\u000a and tumor progression proved to be insurmountable obstacles. Further reports</p> <div class="credits"> <p class="dwt_author">Michael D. Chan; Albert Attia; Stephen B. Tatter; Glenn Lesser; Michael E. Zapadka; Ryan T. Mott; Annette Carter; Kevin P. McMullen; Edward G. Shaw; Thomas E. Ellis</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">418</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/1599993"> <span id="translatedtitle">Degradation of silicon AC-coupled microstrip detectors <span class="hlt">induced</span> by <span class="hlt">radiation</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Results are presented showing the <span class="hlt">radiation</span> response of AC-coupled FOXFET biased microstrip detectors and related test patterns to be used in the microvertex detector of the CDF experiment at Fermi National Laboratory. <span class="hlt">Radiation</span> tolerance of detectors to gamma and proton irradiation has been tested, and the <span class="hlt">radiation-induced</span> variations of the DC electrical parameters have been analyzed. The long-term postirradiation behavior</p> <div class="credits"> <p class="dwt_author">N. Bacchetta; D. Bisello; C. Canali; P. G. Fuochi; Y. Gotra; A. Paccagnella; G. Verzellesi</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">419</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/49933170"> <span id="translatedtitle">Degradation of silicon AC-coupled microstrip detectors <span class="hlt">induced</span> by <span class="hlt">radiation</span> damage</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Results are presented showing the <span class="hlt">radiation</span> response of FOXFET (field-oxide field effect transistor) biased AC-coupled microstrip detectors and related test patterns to be used in the CDF microvertex detector. The <span class="hlt">radiation</span> tolerance of detectors to gamma and proton irradiation has been tested, and the <span class="hlt">radiation</span> <span class="hlt">induced</span> variations of the DC electrical parameters have been analyzed. The long-term post-irradiation behavior of</p> <div class="credits"> <p class="dwt_author">N. Bacchetta; D. Bisello; Y. Gotra; A. Paccagnella; G. Verzellesi; C. Canali; P. G. Fuochi</p> <p class="dwt_publisher"></p> <p class="publishDate">1992-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">420</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2003RaPC...68..893K"> <span id="translatedtitle">Changes <span class="hlt">induced</span> in spice paprika powder by treatment with ionizing <span class="hlt">radiation</span> and saturated steam</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The changes in spice paprika powder <span class="hlt">induced</span> by ionizing <span class="hlt">radiation</span>, saturated steam (SS) and their combination were studied as a function of the absorbed <span class="hlt">radiation</span> dose and the storage time. The SS treatment lead to a decrease in color content (lightening) after 12 weeks of storage, together with the persistence of free radicals and viscosity changes for a longer period. The results suggest that ionizing <span class="hlt">radiation</span> is a more advantageous method as concerns preservation of the quality of spice paprika.</p> <div class="credits"> <p class="dwt_author">Kispéter, J.; Bajúsz-Kabók, K.; Fekete, M.; Szabó, G.; Fodor, E.; Páli, T.</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-12-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_20");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' href="#">4</a> <a onClick='return showDiv("page_5");' href="#">5</a> <a onClick='return showDiv("page_6");' href="#">6</a> <a onClick='return showDiv("page_7");' href="#">7</a> <a onClick='return showDiv("page_8");' href="#">8</a> <a onClick='return showDiv("page_9");' href="#">9</a> <a onClick='return showDiv("page_10");' href="#">10</a> <a onClick='return showDiv("page_11");' href="#">11</a> <a onClick='return showDiv("page_12");' href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a onClick='return showDiv("page_18");' href="#">18</a> <a onClick='return showDiv("page_19");' href="#">19</a> <a onClick='return showDiv("page_20");' href="#">20</a> <a style="font-weight: bold;">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_22");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> </div><!-- page_21 div --> <div id="page_22" class="hiddenDiv"> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_21");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' href="#">4</a> <a onClick='return showDiv("page_5");' href="#">5</a> <a onClick='return showDiv("page_6");' href="#">6</a> <a onClick='return showDiv("page_7");' href="#">7</a> <