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1

Radiation-Induced Amorphization of Crystalline Ice  

NASA Astrophysics Data System (ADS)

Crystalline ice has been unambiguously identified on the surface of most of the Jovian, Saturnian and Uranian satellites, and on the surface of some trans-Neptunian objects such as Quaoar, and 2003 EL61. This result is surprising, as the low surface temperatures of these objects should cause the ice condensed on them to be amorphous. Moreover, the surface of these bodies is constantly exposed to UV photons, solar wind, cosmic rays or energetic charged particles trapped by the planetary magnetic fields, which are known to amorphize crystalline ice. Here, we review 30 years of experimental studies of radiation-induced amorphization of crystalline ice analyzing the differences found between light and heavy ions, electrons and photons. We also present high quality near-infrared absorption spectra for amorphous and crystalline ice before and after we irradiated them with 225 keV protons. After irradiation at 80 K, the crystalline ice spectrum is altered so that it is indistinguishable from the spectrum of amorphous ice, indicating that irradiation can fully amorphize crystalline ice. We will compare these results with previous studies and discuss the astrophysical implication for planetary bodies.

Fama, Marcelo A.; Loeffler, M. J.; Raut, U.; Baragiola, R. A.

2008-09-01

2

Radiation-induced amorphization of crystalline ice  

NASA Astrophysics Data System (ADS)

We study radiation-induced amorphization of crystalline ice, analyzing the results of three decades of experiments with a variety of projectiles, irradiation energy, and ice temperature, finding a similar trend of increasing resistance of amorphization with temperature and inconsistencies in results from different laboratories. We discuss the temperature dependence of amorphization in terms of the 'thermal spike' model. We then discuss the common use of the 1.65 ?m infrared absorption band of water as a measure of degree of crystallinity, an increasingly common procedure to analyze remote sensing data of astronomical icy bodies. The discussion is based on new, high quality near-infrared reflectance absorption spectra measured between 1.4 and 2.2 ?m for amorphous and crystalline ices irradiated with 225 keV protons at 80 K. We found that, after irradiation with 10 15 protons cm -2, crystalline ice films thinner than the ion range become fully amorphous, and that the infrared absorption spectra show no significant changes upon further irradiation. The complete amorphization suggests that crystalline ice observed in the outer Solar System, including trans-neptunian objects, may results from heat from internal sources or from the impact of icy meteorites or comets.

Famá, M.; Loeffler, M. J.; Raut, U.; Baragiola, R. A.

2010-05-01

3

Tyrosine/Cysteine Cluster Sensitizing Human ?D-Crystallin to Ultraviolet Radiation-Induced Photoaggregation in Vitro  

PubMed Central

Ultraviolet radiation (UVR) exposure is a major risk factor for age-related cataract, a protein-aggregation disease of the human lens often involving the major proteins of the lens, the crystallins. ?D-Crystallin (H?D-Crys) is abundant in the nucleus of the human lens, and its folding and aggregation have been extensively studied. Previous work showed that H?D-Crys photoaggregates in vitro upon exposure to UVA/UVB light and that its conserved tryptophans are not required for aggregation. Surprisingly, the tryptophan residues play a photoprotective role because of a distinctive energy-transfer mechanism. H?D-Crys also contains 14 tyrosine residues, 12 of which are organized as six pairs. We investigated the role of the tyrosines of H?D-Crys by replacing pairs with alanines and monitoring photoaggregation using light scattering and SDS-PAGE. Mutating both tyrosines in the Y16/Y28 pair to alanine slowed the formation of light-scattering aggregates. Further mutant studies implicated Y16 as important for photoaggregation. Mass spectrometry revealed that C18, in contact with Y16, is heavily oxidized during UVR exposure. Analysis of multiple mutant proteins by mass spectrometry suggested that Y16 and C18 likely participate in the same photochemical process. The data suggest an initial photoaggregation pathway for H?D-Crys in which excited-state Y16 interacts with C18, initiating radical polymerization. PMID:24410332

2015-01-01

4

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

5

UV-radiation Induced Disruption of Dry-Cavities in Human ?D-crystallin Results in Decreased Stability and Faster Unfolding  

E-print Network

Age-onset cataracts are believed to be expedited by the accumulation of UV-damaged human ?D-crystallins in the eye lens. Here we show with molecular dynamics simulations that the stability of ?D-crystallin is greatly reduced ...

Xia, Zhen

6

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

7

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. For the radiation stability test, selected glass ceramic and crystalline ceramic samples were exposed to different irradiation environments including low fluxes of high-energy (?1-5 MeV) protons and alpha particles generated by an ion accelerator, high fluxes of low-energy (hundreds of keV) krypton particles generated by an ion implanter, and in-situ electron irradiations in a transmission electron microscope. These irradiation experiments were performed to simulate self-radiation effects in a waste form. Ion irradiation-induced microstructural modifications were examined using X-ray diffraction and transmission electron microscopy. Our preliminary results reveal different radiation tolerance in different crystalline phases under various radiation damage environments. However, their stability may be rate dependent which may limit the waste loading that can be achieved.

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

2014-05-01

8

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. PMID:19831840

Prasad, Gautam; Haas-Kogan, Daphne A.

2013-01-01

9

Radiation-induced meningiomas.  

PubMed

High dose radiation-induced meningiomas are a rare, severe and late complication of craniospinal radiotherapy for brain tumors. Radiation-induced meningiomas are, according to the literature, several times more frequent than radiogenic gliomas and sarcomas. It is suggested that every new case of radiogenic meningioma has to be reported to elucidate this particular pathologic entity with its many grey areas. In addition to high dose radiation-induced meningiomas, intracranial meningiomas were observed in patients who underwent low-dose radiation for tinea capitis in childhood, applied en mass to immigrants coming to Israel from the North Africa and the Middle East during the 1950. Authors summarize the data on radiogenic meningiomas from the literature and, as the previous radiotherapy may confer a low, but life-long risk for meningioma occurrence, they suggest that surveillance MRI after high dose cerebrospinal radiotherapy should be extended to several (3-5) decades after radiotherapy. PMID:11949834

Boljesíkova, E; Chorvath, M

2001-01-01

10

Radiation-induced amorphization of intermetallic compounds  

NASA Astrophysics Data System (ADS)

In the present paper, important results of our recent computer simulation of radiation-induced amorphization in the ordered compounds CuTi and Cu4Ti3 are summarized. The energetic, structural, thermodynamic and mechanical responses of these intermetallics during chemical disordering, point-defect production and heating were simulated, using molecular dynamics and embedded-atom potentials. From the atomistic details obtained, the critical role of radiation-induced structural disorder in driving the crystalline-to-amorphous phase transformation is discussed.

Lam, N. Q.; Sabochick, M. J.; Okamoto, P. R.

1994-06-01

11

Crystalline undulator radiation and sub-harmonic bifurcation of system  

NASA Astrophysics Data System (ADS)

Looking for new light sources, especially short wavelength laser light sources has attracted widespread attention. This paper analytically describes the radiation of a crystalline undulator field by the sine-squared potential. In the classical mechanics and the dipole approximation, the motion equation of a particle is reduced to a generalized pendulum equation with a damping term and a forcing term. The bifurcation behavior of periodic orbits is analyzed by using the Melnikov method and the numerical method, and the stability of the system is discussed. The results show that, in principle, the stability of the system relates to its parameters, and only by adjusting these parameters appropriately can the occurrence of bifurcation be avoided or suppressed.

Luo, Xiao-Hua; He, Wei; Wu, Mu-Ying; Shao, Ming-Zhu; Luo, Shi-Yu

2013-06-01

12

[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

13

Surfactant-induced postsynthetic modulation of Pd nanoparticle crystallinity.  

PubMed

Modulation of Pd nanoparticle (NP) crystallinity is achieved by switching the surfactants of different binding strengths. Pd NPs synthesized in the presence of weak binding surfactants such as oleylamine possess polyhedral shapes and a polycrystalline nature. When oleylamine is substituted by trioctylphosphine, a much stronger binding surfactant, the particles become spherical and their crystallinity decreases significantly. Moreover, the Pd NPs reconvert their polycrystalline structure when the surfactant is switched back to oleylamine. Through control experiments and molecular dynamics simulation, we propose that this unusual nanocrystallinity transition induced by surfactant exchange was resulted from a counterbalance between the surfactant binding energy and the nanocrystal adhesive energy. The findings represent a novel postsynthetic approach to tailoring the structure and corresponding functional performance of nanomaterials. PMID:21355537

Liu, Yi; Wang, Chao; Wei, Yujie; Zhu, Leyi; Li, Dongguo; Jiang, J Samuel; Markovic, Nenad M; Stamenkovic, Vojislav R; Sun, Shouheng

2011-04-13

14

Surfactant-induced postsynthetic modulation of Pd nanoparticle crystallinity.  

SciTech Connect

Modulation of Pd nanoparticle (NP) crystallinity is achieved by switching the surfactants of different binding strengths. Pd NPs synthesized in the presence of weak binding surfactants such as oleylamine possess polyhedral shapes and a polycrystalline nature. When oleylamine is substituted by trioctylphosphine, a much stronger binding surfactant, the particles become spherical and their crystallinity decreases significantly. Moreover, the Pd NPs reconvert their polycrystalline structure when the surfactant is switched back to oleylamine. Through control experiments and molecular dynamics simulation, we propose that this unusual nanocrystallinity transition induced by surfactant exchange was resulted from a counterbalance between the surfactant binding energy and the nanocrystal adhesive energy. The findings represent a novel postsynthetic approach to tailoring the structure and corresponding functional performance of nanomaterials.

Liu, Y.; Wang, C.; Wei, Y.; Zhu, L.; Li, D.; Jiang, J. S.; Markovic, N. M.; Stamenkovic, V. R.; Sun, S. (Materials Science Division); (Brown Univ.); (Chinese Academy of Sciences)

2011-02-01

15

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

16

Radiation Induced Oral Mucositis  

PubMed Central

Patients receiving radiotherapy or chemotherapy will receive some degree of oral mucositis The incidence of oral mucositis was especially high in patients: (i) With primary tumors in the oral cavity, oropharynx, or nasopharynx; (ii) who also received concomitant chemotherapy; (iii) who received a total dose over 5,000 cGy; and (iv) who were treated with altered fractionation radiation schedules. Radiation-induced oral mucositis affects the quality of life of the patients and the family concerned. The present day management of oral mucositis is mostly palliative and or supportive care. The newer guidelines are suggesting Palifermin, which is the first active mucositis drug as well as Amifostine, for radiation protection and cryotherapy. The current management should focus more on palliative measures, such as pain management, nutritional support, and maintenance, of good oral hygiene PMID:20668585

PS, Satheesh Kumar; Balan, Anita; Sankar, Arun; Bose, Tinky

2009-01-01

17

Radiation Induced Genomic Instability  

SciTech Connect

Radiation induced genomic instability can be observed in the progeny of irradiated cells multiple generations after irradiation of parental cells. The phenotype is well established both in vivo (Morgan 2003) and in vitro (Morgan 2003), and may be critical in radiation carcinogenesis (Little 2000, Huang et al. 2003). Instability can be induced by both the deposition of energy in irradiated cells as well as by signals transmitted by irradiated (targeted) cells to non-irradiated (non-targeted) cells (Kadhim et al. 1992, Lorimore et al. 1998). Thus both targeted and non-targeted cells can pass on the legacy of radiation to their progeny. However the radiation induced events and cellular processes that respond to both targeted and non-targeted radiation effects that lead to the unstable phenotype remain elusive. The cell system we have used to study radiation induced genomic instability utilizes human hamster GM10115 cells. These cells have a single copy of human chromosome 4 in a background of hamster chromosomes. Instability is evaluated in the clonal progeny of irradiated cells and a clone is considered unstable if it contains three or more metaphase sub-populations involving unique rearrangements of the human chromosome (Marder and Morgan 1993). Many of these unstable clones have been maintained in culture for many years and have been extensively characterized. As initially described by Clutton et al., (Clutton et al. 1996) many of our unstable clones exhibit persistently elevated levels of reactive oxygen species (Limoli et al. 2003), which appear to be due dysfunctional mitochondria (Kim et al. 2006, Kim et al. 2006). Interestingly, but perhaps not surprisingly, our unstable clones do not demonstrate a “mutator phenotype” (Limoli et al. 1997), but they do continue to rearrange their genomes for many years. The limiting factor with this system is the target – the human chromosome. While some clones demonstrate amplification of this chromosome and thus lend themselves to prolonged study, many tend to eliminate or rearrange the target chromosome until it is too small for further rearrangement. The observed frequency of induced instability by low and high linear-energy-transfer radiations greatly exceeds that observed for nuclear gene mutations at similar doses; hence, mutation of a gene or gene family is unlikely to be the initiating mechanism. Once initiated however, there is evidence in the GM10115 model system that it can be perpetuated over time by dicentric chromosome formation followed by bridge breakage fusion cycles (Marder and Morgan 1993), as well as recombinational events involving interstitial telomere like repeat sequences (Day et al. 1998). There is also increasing evidence that inflammatory type reactions (Lorimore et al. 2001, Lorimore and Wright 2003), presumably involving reactive oxygen and nitrogen species as well as cytokines and chemokines might be involved in driving the ustable phenotype (Liaikis et al. 2007, Hei et al. 2008). To this end there is very convincing evidence for such reactions being involved in another non-targeted effect associated with ionizing radiation, the bystander effect (Hei et al. 2008). Clearly the link between induced instability and bystander effects suggests common processes and inflammatory type reactions will likely be the subject of future investigation.

Morgan, William F.

2011-03-01

18

[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

19

Fs-laser induced flexibility increase in the crystalline lens  

NASA Astrophysics Data System (ADS)

Presbyopia is one age related effect every human is suffering beginning at the age of about 45 years. Reading glasses are the conventional treatment so far. According to the Helmholtz theory the loss of accommodation in age is due to the hardening and the resulting loss of elasticity of the crystalline lens. However the ciliary muscle and the lens capsule stay active, respectively. Therefore a possible treatment concept is to regain the flexibility by inducing gliding planes in form of microcuts inside the lens. The increase of flexibility in young porcine lenses by different cutting patterns was shown by Ripken et al. 1, 2 who verified the increase in flexibility by the spinning test introduced by Fisher. 3 We will present our first measurements of flexibility increase of human donor lenses. Furthermore the influence of the laser cuts into the lens on the accommodation amplitude will be shown in a three dimensional finite-element simulation.

Schumacher, S.; Fromm, M.; Lakharia, R.; Schaefer, M.; Oberheide, U.; Ripken, T.; Breitenfeld, P.; Gerten, G.; Ertmer, W.; Lubatschowksi, H.

2007-02-01

20

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

21

EFFECT OF LASER INDUCED CRYSTALLINITY MODIFICATION ON BIODEGRADATION PROFILE OF POLY(L-LACTIC ACID)  

E-print Network

of surface crystallinity may have potential to tailor the initial PLLA degradation ratEFFECT OF LASER INDUCED CRYSTALLINITY MODIFICATION ON BIODEGRADATION PROFILE OF POLY(L-LACTIC ACID prevents the embedded drugs from releasing at the designed rate in the early stage. PLLA degradation

Yao, Y. Lawrence

22

Ultrafast Laser Induced Thermo-Elasto-Visco-Plastodynamics in Single Crystalline Silicon  

E-print Network

pulse width in Laser Induced Stress Waves Thermometry (LISWT) for single crystalline silicon processing motivated the work. The model formulation developed is of a hyperbolic type capable of characterizing non-thermal melting and thermo...

Qi, Xuele

2011-02-22

23

Radiation effects in crystalline ceramics for the immobilization of high-level nuclear waste and plutonium  

Microsoft Academic Search

This review provides a comprehensive evaluation of the state-of-knowledge of radiation effects in crystalline ceramics that may be used for the immobilization of high-level nuclear waste and plutonium. The current understanding of radiation damage processes, defect generation, microstructure development, theoretical methods, and experimental methods are reviewed. Fundamental scientific and technological issues that offer opportunities for research are identified. The most

W. J. Weber; R. C. Ewing; C. R. A. Catlow; T. Diaz de La Rubia; L. W. Hobbs; C. Kinoshita; Hj. Matzke; A. T. Motta; M. Nastasi; E. H. K. Salje; E. R. Vance; S. J. Zinkle

1998-01-01

24

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. PMID:24874187

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

2014-01-01

25

Radiation Induced Osmosis  

NASA Astrophysics Data System (ADS)

Pressure transients are observed in absorbing gases at low pressure in a non-resonant spectrophone. At very low pressure (transition saturated) the transient is negative on irradiation. Interpretation is given in terms of thermodynamics of laser driven systems. The local value of the partition function depends exponentially on the incident radiation's intensity. The observed depression on irradiation is the consequence of the law of mass action applied to inhomogeneously irradiated systems.

de Hemptinne, X.

1985-03-01

26

Radiation-induced cardiovascular effects  

NASA Astrophysics Data System (ADS)

Recent epidemiological studies indicate that exposure to ionising radiation enhances the risk of cardiovascular mortality and morbidity in a moderate but significant manner. Our goal is to identify molecular mechanisms involved in the pathogenesis of radiation-induced cardiovascular disease using cellular and mouse models. Two radiation targets are studied in detail: the vascular endothelium that plays a pivotal role in the regulation of cardiac function, and the myocardium, in particular damage to the cardiac mitochondria. Ionising radiation causes immediate and persistent alterations in several biological pathways in the endothelium in a dose- and dose-rate dependent manner. High acute and cumulative doses result in rapid, non-transient remodelling of the endothelial cytoskeleton, as well as increased lipid peroxidation and protein oxidation of the heart tissue, independent of whether exposure is local or total body. Proteomic and functional changes are observed in lipid metabolism, glycolysis, mitochondrial function (respiration, ROS production etc.), oxidative stress, cellular adhesion, and cellular structure. The transcriptional regulators Akt and PPAR alpha seem to play a central role in the radiation-response of the endothelium and myocardium, respectively. We have recently started co-operation with GSI in Darmstadt to study the effect of heavy ions on the endothelium. Our research will facilitate the identification of biomarkers associated with adverse cardiac effects of ionising radiation and may lead to the development of countermeasures against radiation-induced cardiac damage.

Tapio, Soile

27

Crystalline nanostructures on Ge surfaces induced by ion irradiation  

NASA Astrophysics Data System (ADS)

Besides conventional low efficiency lithographic techniques broad ion beam irradiation is a simple and potentially mass productive technique to fabricate nanoscale patterns on various semiconductor surfaces. The main drawback of this method is that the irradiated semiconductor surfaces are amorphized, which strongly limits the potential application of these nanostructures in electronic and optoelectronic devices. In this work we report that high-quality crystalline nanostructure patterns are formed on Ge surfaces via Ar+ irradiation at elevated temperatures. This pattern formation process resembles the pattern formation in homoepitaxy. Therefore, the process is discussed based on a 'reverse epitaxy' mechanism.

Ou, Xin; Facsko, Stefan

2014-12-01

28

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

?-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. PMID:23383327

Hamann, Séverine; Métrailler, Sylviane; Schorderet, Daniel F; Cottet, Sandra

2013-01-01

29

Analysis of rapidly synthesized guest-filled porous complexes with synchrotron radiation: practical guidelines for the crystalline sponge method  

PubMed Central

A detailed set of synthetic and crystallographic guidelines for the crystalline sponge method based upon the analysis of expediently synthesized crystal sponges using third-generation synchrotron radiation are reported. The procedure for the synthesis of the zinc-based metal–organic framework used in initial crystal sponge reports has been modified to yield competent crystals in 3 days instead of 2 weeks. These crystal sponges were tested on some small molecules, with two being unexpectedly difficult cases for analysis with in-house diffractometers in regard to data quality and proper space-group determination. These issues were easily resolved by the use of synchrotron radiation using data-collection times of less than an hour. One of these guests induced a single-crystal-to-single-crystal transformation to create a larger unit cell with over 500 non-H atoms in the asymmetric unit. This led to a non-trivial refinement scenario that afforded the best Flack x absolute stereochemical determination parameter to date for these systems. The structures did not require the use of PLATON/SQUEEZE or other solvent-masking programs, and are the highest-quality crystalline sponge systems reported to date where the results are strongly supported by the data. A set of guidelines for the entire crystallographic process were developed through these studies. In particular, the refinement guidelines include strategies to refine the host framework, locate guests and determine occupancies, discussion of the proper use of geometric and anisotropic displacement parameter restraints and constraints, and whether to perform solvent squeezing/masking. The single-crystal-to-single-crystal transformation process for the crystal sponges is also discussed. The presented general guidelines will be invaluable for researchers interested in using the crystalline sponge method at in-house diffraction or synchrotron facilities, will facilitate the collection and analysis of reliable high-quality data, and will allow construction of chemically and physically sensible models for guest structural determination. PMID:25537388

Ramadhar, Timothy R.; Zheng, Shao-Liang; Chen, Yu-Sheng; Clardy, Jon

2015-01-01

30

Analysis of rapidly synthesized guest-filled porous complexes with synchrotron radiation: practical guidelines for the crystalline sponge method.  

PubMed

A detailed set of synthetic and crystallographic guidelines for the crystalline sponge method based upon the analysis of expediently synthesized crystal sponges using third-generation synchrotron radiation are reported. The procedure for the synthesis of the zinc-based metal-organic framework used in initial crystal sponge reports has been modified to yield competent crystals in 3 days instead of 2 weeks. These crystal sponges were tested on some small molecules, with two being unexpectedly difficult cases for analysis with in-house diffractometers in regard to data quality and proper space-group determination. These issues were easily resolved by the use of synchrotron radiation using data-collection times of less than an hour. One of these guests induced a single-crystal-to-single-crystal transformation to create a larger unit cell with over 500 non-H atoms in the asymmetric unit. This led to a non-trivial refinement scenario that afforded the best Flack x absolute stereochemical determination parameter to date for these systems. The structures did not require the use of PLATON/SQUEEZE or other solvent-masking programs, and are the highest-quality crystalline sponge systems reported to date where the results are strongly supported by the data. A set of guidelines for the entire crystallographic process were developed through these studies. In particular, the refinement guidelines include strategies to refine the host framework, locate guests and determine occupancies, discussion of the proper use of geometric and anisotropic displacement parameter restraints and constraints, and whether to perform solvent squeezing/masking. The single-crystal-to-single-crystal transformation process for the crystal sponges is also discussed. The presented general guidelines will be invaluable for researchers interested in using the crystalline sponge method at in-house diffraction or synchrotron facilities, will facilitate the collection and analysis of reliable high-quality data, and will allow construction of chemically and physically sensible models for guest structural determination. PMID:25537388

Ramadhar, Timothy R; Zheng, Shao Liang; Chen, Yu Sheng; Clardy, Jon

2015-01-01

31

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

32

Crack propagation induced heating in crystalline energetic materials W. Holmes,a)  

E-print Network

Crack propagation induced heating in crystalline energetic materials W. Holmes,a) R. S. Francis in the vicinity of a propagating crack in a molecular crystal. In the model, energy from a moving crack tip is released as phonons in proximity to the crack. Initially the phonons and the molecular vibrations

Fayer, Michael D.

33

Laser-Induced Temperature Distribution in Photo-Alignment of Azobenzene Liquid Crystalline Side Chain Polymers  

Microsoft Academic Search

A theoretical model has been worked out to describe a temperature field, which is established within a film of isotropic trans azobenzene liquid crystalline side chain (LCSC) polymers when a linearly polarized laser beam illuminates it, and contributes to the photo-induced alignment behavior of LCSC polymers at an ambient temperature below the glassy transition temperature (Tg). The distribution of the

Xinghua Wang; Weilun Shen; Qijin Zhang; Teng Li; Xiaofang Cheng

2000-01-01

34

Defect-induced birefringence in crystalline silicon ingots  

NASA Astrophysics Data System (ADS)

Birefringence induced by crystal defects has been successfully characterized as standard ingot form in Si crystals by using a scanning infrared polariscope. It is found that there is a certain amount of defect-induced birefringence besides the birefringence due to the optical anisotropy in CZ Si crystals. If the infrared probing light is introduced to the crystallographic ?ngle100rangle directions, then the defect-induced birefringence is clearly observed with no influence of the optical anisotropy in cubic crystals. Although it is difficult to evaluate the absolute value of crystal defects, it is demonstrated that the SIRP measurement is very useful to nondestructively characterize the quality of Si crystals as standard ingot form without any special treatment.

Yamada, M.; Zui, N.; Chu, T.

2004-07-01

35

Hydrogeologic controls on induced seismicity in crystalline basement rocks due to fluid injection into basal reservoirs.  

PubMed

A series of Mb 3.8-5.5 induced seismic events in the midcontinent region, United States, resulted from injection of fluid either into a basal sedimentary reservoir with no underlying confining unit or directly into the underlying crystalline basement complex. The earthquakes probably occurred along faults that were likely critically stressed within the crystalline basement. These faults were located at a considerable distance (up to 10?km) from the injection wells and head increases at the hypocenters were likely relatively small (?70-150?m). We present a suite of simulations that use a simple hydrogeologic-geomechanical model to assess what hydrogeologic conditions promote or deter induced seismic events within the crystalline basement across the midcontinent. The presence of a confining unit beneath the injection reservoir horizon had the single largest effect in preventing induced seismicity within the underlying crystalline basement. For a crystalline basement having a permeability of 2?×?10(-17) ?m(2) and specific storage coefficient of 10(-7) /m, injection at a rate of 5455?m(3) /d into the basal aquifer with no underlying basal seal over 10?years resulted in probable brittle failure to depths of about 0.6?km below the injection reservoir. Including a permeable (kz ?=?10(-13) ?m(2) ) Precambrian normal fault, located 20?m from the injection well, increased the depth of the failure region below the reservoir to 3?km. For a large permeability contrast between a Precambrian thrust fault (10(-12) ?m(2) ) and the surrounding crystalline basement (10(-18) ?m(2) ), the failure region can extend laterally 10?km away from the injection well. PMID:23745958

Zhang, Yipeng; Person, Mark; Rupp, John; Ellett, Kevin; Celia, Michael A; Gable, Carl W; Bowen, Brenda; Evans, James; Bandilla, Karl; Mozley, Peter; Dewers, Thomas; Elliot, Thomas

2013-01-01

36

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

37

Ultrasound visualization of internal crystalline lens deformation using laser-induced microbubbles  

NASA Astrophysics Data System (ADS)

The progressive loss of accommodation of the eye, called presbyopia, affects people with age and can result in a complete loss of accommodation by about age 55 years. It is generally accepted that presbyopia is due to an increase in stiffness of the lens. With increasing age, the stiffness of the crystalline lens nucleus increases faster than that of the cortex. During accommodation, the deformation of different parts of the crystalline lens is different and likely changes with age. However, a direct observation of crystalline lens deformation and strain distribution is difficult because although imaging methods such as OCT or Scheimpflug imaging can distinguish cortex and nucleus, they cannot determine their regional deformation. Here, patterns of laser-induced microbubbles were created in gelatin phantoms and different parts of excised animal crystalline lenses and their displacements in response to external deformation were tracked by ultrasound imaging. In the animal lenses, the deformation of the lens cortex was greater than that of nucleus and this regional difference is greater for a 27-month-old bovine lens than for a 6-month-old porcine lens. This approach enables visualization of localized, regional deformation of crystalline lenses and, if applied to lenses from animal species that undergo accommodation, may help to understand the mechanisms of accommodation and presbyopia, improve diagnostics, and, potentially, aid in the development of new methods of lens modifying presbyopia treatments.

Karpiouk, Andrei B.; Aglyamov, Salavat R.; Glasser, Adrian; Emelianov, Stanislav Y.

2014-02-01

38

Influence of various types of ionizing radiation on the properties of polymers. Thermal conductivity and crystallinity of polytetrafluoroethylene  

SciTech Connect

The influence of the {gamma} radiation of {sup 60}Co, 100 MeV protons, and neutrons of a water-moderated water-cooled reactor on the thermal conductivity and crystallinity of polytetrafluoroethylene was investigated. Specific features of the type of ionizing radiation were detected under the influence of neutrons. 10 refs., 2 figs., 1 tab.

Briskman, B.A.; Rogova, V.N.; Chikina, Z.N.

1992-09-01

39

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

40

Alpha-crystallin-mediated protection of lens cells against heat and oxidative stress-induced cell death.  

PubMed

In addition to their key role as structural lens proteins, ?-crystallins also appear to confer protection against many eye diseases, including cataract, retinitis pigmentosa, and macular degeneration. Exogenous recombinant ?-crystallin proteins were examined for their ability to prevent cell death induced by heat or oxidative stress in a human lens epithelial cell line (HLE-B3). Wild type ?A- or ?B-crystallin (WT-?A and WT-?B) and ?A- or ?B-crystallins, modified by the addition of a cell penetration peptide (CPP) designed to enhance the uptake of proteins into cells (gC-?B, TAT-?B, gC-?A), were produced by recombinant methods. In vitro chaperone-like assays were used to assay the ability of ?-crystallins to protect client proteins from chemical or heat induced aggregation. In vivo viability assays were performed in HLE-B3 to determine whether pre-treatment with ?-crystallins reduced death after exposure to oxidative or heat stress. Most of the five recombinant ?-crystallin proteins tested conferred some in vitro protection from protein aggregation, with the greatest effect seen with WT-?B and gC-?B. All ?-crystallins displayed significant protection to oxidative stress induced cell death, while only the ?B-crystallins reduced cell death induced by thermal stress. Our findings indicate that the addition of the gC tag enhanced the protective effect of ?B-crystallin against oxidative but not thermally-induced cell death. In conclusion, modifications that increase the uptake of ?-crystallin proteins into cells, without destroying their chaperone-like activity and anti-apoptotic functions, create the potential to use these proteins therapeutically. PMID:24275510

Christopher, Karen L; Pedler, Michelle G; Shieh, Biehuoy; Ammar, David A; Petrash, J Mark; Mueller, Niklaus H

2014-02-01

41

REVIEW ARTICLE: Sputter-induced crystalline layers and epitaxial overlayers on quasicrystal surfaces  

Microsoft Academic Search

We present here an overview of surface and interface studies on various quasicrystals, focusing on areas where reflection high-energy electron diffraction plays an important role. Subjects included here are sputter-induced crystalline layers, surface alloying and epitaxial films. These phenomena are observed on the high symmetry surface of Al-based quasicrystals, such as decagonal Al-Ni-Co, icosahedral (i) Al-Cu-Fe and i-Al-Cu-Ru. For comparison,

M. Shimoda; H. R. Sharma

2008-01-01

42

Laser-Induced Forward Transfer-printing of pre-machined crystalline magneto-optic garnet discs  

E-print Network

Laser-Induced Forward Transfer-printing of pre-machined crystalline magneto-optic garnet discs-optic Yttrium Iron Garnet films. Debris-free circular micro-discs with smooth edges and surface uniformity have

Sóbester, András

43

Medium-induced multi-photon radiation  

E-print Network

We study the spectrum of multi-photon radiation off a fast quark in medium in the BDMPS/ASW approach. We reproduce the medium-induced one-photon radiation spectrum in dipole approximation, and go on to calculate the two-photon radiation in the Moli\\`{e}re limit. We find that in this limit the LPM effect holds for medium-induced two-photon ladder emission.

Hao Ma; Carlos A. Salgado; Konrad Tywoniuk

2011-05-29

44

Thermal Stress Induced Aggregation of Aquaporin 0 (AQP0) and Protection by ?-Crystallin via Its Chaperone Function  

PubMed Central

Aquaporin 0 (AQP0) formerly known as membrane intrinsic protein (MIP), is expressed exclusively in the lens during terminal differentiation of fiber cells. AQP0 plays an important role not only in the regulation of water content but also in cell-to-cell adhesion of the lens fiber cells. We have investigated the thermal stress-induced structural alterations of detergent (octyl glucoside)-solubilized calf lens AQP0. The results show an increase in the amount of AQP0 that aggregated as the temperature increased from 40°C to 65°C. ?-Crystallin, molecular chaperone abundantly present in the eye lens, completely prevented the AQP0 aggregation at a 1?1 (weight/weight) ratio. Since ?-crystallin consists of two gene products namely ?A- and ?B-crystallins, we have tested the recombinant proteins on their ability to prevent thermal-stress induced AQP0 aggregation. In contrast to the general observation made with other target proteins, ?A-crystallin exhibited better chaperone-like activity towards AQP0 compared to ?B-crystallin. Neither post-translational modifications (glycation) nor C-terminus truncation of AQP0 have any appreciable effect on its thermal aggregation properties. ?-Crystallin offers similar protection against thermal aggregation as in the case of the unmodified AQP0, suggesting that ?crystallin may bind to either intracellular loops or other residues of AQP0 that become exposed during thermal stress. Far-UV circular dichroism studies indicated a loss of ?helical structures when AQP0 was subjected to temperatures above 45°C, and the presence of ?-crystallin stabilized these secondary structures. We report here, for the first time, that ?-crystallin protects AQP0 from thermal aggregation. Since stress-induced structural perturbations of AQP0 may affect the integrity of the lens, presence of the molecular chaperone, ?-crystallin (particularly ?A-crystallin) in close proximity to the lens membrane is physiologically relevant. PMID:24312215

Swamy-Mruthinti, Satyanarayana; Srinivas, Volety; Hansen, John E.; Rao, Ch Mohan

2013-01-01

45

Thermal stress induced aggregation of aquaporin 0 (AQP0) and protection by ?-crystallin via its chaperone function.  

PubMed

Aquaporin 0 (AQP0) formerly known as membrane intrinsic protein (MIP), is expressed exclusively in the lens during terminal differentiation of fiber cells. AQP0 plays an important role not only in the regulation of water content but also in cell-to-cell adhesion of the lens fiber cells. We have investigated the thermal stress-induced structural alterations of detergent (octyl glucoside)-solubilized calf lens AQP0. The results show an increase in the amount of AQP0 that aggregated as the temperature increased from 40°C to 65°C. ?-Crystallin, molecular chaperone abundantly present in the eye lens, completely prevented the AQP0 aggregation at a 1?1 (weight/weight) ratio. Since ?-crystallin consists of two gene products namely ?A- and ?B-crystallins, we have tested the recombinant proteins on their ability to prevent thermal-stress induced AQP0 aggregation. In contrast to the general observation made with other target proteins, ?A-crystallin exhibited better chaperone-like activity towards AQP0 compared to ?B-crystallin. Neither post-translational modifications (glycation) nor C-terminus truncation of AQP0 have any appreciable effect on its thermal aggregation properties. ?-Crystallin offers similar protection against thermal aggregation as in the case of the unmodified AQP0, suggesting that ?crystallin may bind to either intracellular loops or other residues of AQP0 that become exposed during thermal stress. Far-UV circular dichroism studies indicated a loss of ?helical structures when AQP0 was subjected to temperatures above 45°C, and the presence of ?-crystallin stabilized these secondary structures. We report here, for the first time, that ?-crystallin protects AQP0 from thermal aggregation. Since stress-induced structural perturbations of AQP0 may affect the integrity of the lens, presence of the molecular chaperone, ?-crystallin (particularly ?A-crystallin) in close proximity to the lens membrane is physiologically relevant. PMID:24312215

Swamy-Mruthinti, Satyanarayana; Srinivas, Volety; Hansen, John E; Rao, Ch Mohan

2013-01-01

46

Nonthermal effects on microwave radiation on ionic diffusion in ionic crystalline ceramics  

SciTech Connect

Numerous claims have been made of observations that microwave heating of ceramics promotes faster processing or solid state reactions (e.g., sintering, bonding, tracer ion diffusion) than conventional furnace heating. These claims are controversial due to the absence of a verifiable theoretical explanation as well as questions on the interpretation of sample temperature measurements obtained in the presence of microwave fields or during microwave heating. A recent experimental investigation has clearly established that intense microwave fields can yield enhanced ion (or vacancy) diffusion in ionic crystalline ceramics. The results are in qualitative agreement with a model in which the microwave fields exert a ponderomotive or radiation pressure acting near the surfaces of NaCl crystals or grains. It is believed that this phenomenon explains the observations of microwave-enhanced tracer ion diffusion in higher temperature oxide ceramics and glasses. Future work will explore the role of this phenomenon in grain boundary diffusion and sintering during microwave processing of ceramics.

Freeman, S.A.; Booske, J.H.; Cooper, R.F. [Univ. of Wisconsin, Madison, WI (United States)

1995-12-31

47

Temperature dependence of the radiative recombination coefficient in crystalline silicon from spectral photoluminescence  

SciTech Connect

The radiative recombination coefficient B(T) in crystalline silicon is determined for the temperature range 90–363?K, and in particular from 270 to 350?K with an interval of 10?K, where only sparse data are available at present. The band-band absorption coefficient established recently by Nguyen et al. [J. Appl. Phys. 115, 043710 (2014)] via photoluminescence spectrum measurements is employed to compute the values of B(T) at various temperatures. The results agree very well with literature data from Trupke et al. [J. Appl. Phys. 94, 4930 (2003).] We present a polynomial parameterization describing the temperature dependence of the product of B(T) and the square of the intrinsic carrier density. We also find that B(T) saturates at a near constant value at room temperature and above for silicon samples with relatively low free carrier densities.

Nguyen, Hieu T., E-mail: hieu.nguyen@anu.edu.au; Macdonald, Daniel [Research School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 0200 (Australia); Baker-Finch, Simeon C. [Research School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 0200 (Australia); PV Lighthouse, Coledale, NSW 2515 (Australia)

2014-03-17

48

Radiation-induced defect centers in glass ceramics  

NASA Astrophysics Data System (ADS)

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+ center, several types of oxygen hole centers (OHCs), an aluminum-oxygen hole center (Al-OHC), an Fe3+ center, Ti3+ and Zr3+ centers, and three types of As centers. An Sb4+ 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+ 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.

1989-01-01

49

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

50

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

51

Formation kinetics of copper-related light-induced degradation in crystalline silicon  

NASA Astrophysics Data System (ADS)

Light-induced degradation (LID) is a deleterious effect in crystalline silicon, which is considered to originate from recombination-active boron-oxygen complexes and/or copper-related defects. Although LID in both cases appears as a fast initial decay followed by a second slower degradation, we show that the time constant of copper-related degradation increases with increasing boron concentration in contrast to boron-oxygen LID. Temperature-dependent analysis reveals that the defect formation is limited by copper diffusion. Finally, interface defect density measurements confirm that copper-related LID is dominated by recombination in the wafer bulk.

Lindroos, J.; Savin, H.

2014-12-01

52

Degenerate crystalline silicon films by aluminum-induced crystallization of boron-doped amorphous silicon  

NASA Astrophysics Data System (ADS)

Degenerate p-type crystalline silicon film with a hole concentration of 4 × 1021 cm-3 was investigated using aluminum-induced crystallization (AIC) of boron-doped amorphous silicon (a-Si). The AIC mechanism is different from that in the undoped AIC-Si. Boron atoms accumulate at Al layer forming a boron bump and segregate the Al atoms into Si layer, resulting to the formation of AlSi alloy. The degeneracy is not attributed to boron doping but instead to the AlSi alloy. Observations show that Al and Si layer transfer occurs not at original interface of Al and Si, but at the boron bump.

Hwang, J. D.; Luo, L. C.; Hsueh, T. J.; Hwang, S. B.

2012-10-01

53

REVIEW ARTICLE: Sputter-induced crystalline layers and epitaxial overlayers on quasicrystal surfaces  

NASA Astrophysics Data System (ADS)

We present here an overview of surface and interface studies on various quasicrystals, focusing on areas where reflection high-energy electron diffraction plays an important role. Subjects included here are sputter-induced crystalline layers, surface alloying and epitaxial films. These phenomena are observed on the high symmetry surface of Al-based quasicrystals, such as decagonal Al-Ni-Co, icosahedral (i) Al-Cu-Fe and i-Al-Cu-Ru. For comparison, studies on i-Ag-In-Yb quasicrystal, an isostructure of the binary i-Cd-Yb quasicrystal, and ?'-Al-Pd-Mn approximant are also included.

Shimoda, M.; Sharma, H. R.

2008-08-01

54

Radiation-induced thyroid disease  

SciTech Connect

Ionizing radiation has been demonstrated to result in a number of changes in the human thyroid gland. At lower radiation dose levels (between 10 and 1500 rads), benign and malignant neoplasms appear to be the dominant effect, whereas at higher dose levels functional changes and thyroiditis become more prevalent. In all instances, the likelihood of the effect is related to the amount and type of radiation exposure, time since exposure, and host factors such as age, sex, and heredity. The author's current approach to the evaluation of patients with past external radiation therapy to the thyroid is discussed. The use of prophylactic thyroxine (T4) therapy is controversial. While T4 therapy may not be useful in preventing carcinogenesis when instituted many years after radiation exposure, theoretically T4 may block TSH secretion and stimulation of damaged cells to undergo malignant transformation when instituted soon after radiation exposure.

Maxon, H.R.

1985-09-01

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

Molecular Pathways: Radiation-induced Cognitive Impairment  

PubMed Central

Approximately 200,000 patients/year in the US will receive partial or whole brain irradiation for the treatment of primary or metastatic brain cancer. Early and delayed radiation effects are transient and reversible with modern therapeutic standards; yet late radiation effects (?6 months postirradiation) remain a significant risk, resulting in progressive cognitive impairment. These include functional deficits in memory, attention, and executive function that severely affect the patient’s quality of life (QOL). The mechanisms underlying radiation-induced cognitive impairment remain ill defined. Classically, radiation-induced alterations in vascular and neuroinflammatory glial cell clonogenic populations were hypothesized to be responsible for radiation-induced brain injury. Recently, preclinical studies have focused on the hippocampus, one of two sites of adult neurogenesis within the brain, which plays an important role in learning and memory. Radiation ablates hippocampal neurogenesis, alters neuronal function, and induces neuroinflammation. Neuronal stem cells implanted into the hippocampus prevent the decrease in neurogenesis and improve cognition following irradiation. Clinically prescribed drugs, including PPAR ? and ? agonists, as well as RAS blockers, prevent radiation-induced neuroinflammation and cognitive impairment independent of improved neurogenesis. Translating these exciting findings to the clinic offers the promise of improving the QOL of brain tumor patients who receive radiotherapy. PMID:23388505

Greene-Schloesser, Dana; Moore, Elizabeth; Robbins, Mike E

2013-01-01

57

Medium-induced gluon radiation: an update  

E-print Network

The theory of radiative parton energy loss in a static QCD medium is updated. We show that for an incoming parton of large energy $E$ undergoing a hard, small angle scattering in the medium rest frame (i.e., $p_\\perp /E \\ll 1$ with $p_\\perp$ the final parton transverse momentum), the medium-induced radiative energy loss due to soft rescatterings is proportional to $E$. It arises from gluon radiation with large formation time $t_f \\gg L$, i.e., fully coherent over the size $L$ of the medium. In particular, in a physical (light-cone) gauge, the medium-induced radiation spectrum arises from the interference between initial and final state radiation. This result, rigorously derived to all orders in the opacity expansion, invalidates a common belief that any medium-induced energy loss through a finite size target should be bounded in the high-energy limit. We also review the case of a parton suddenly annihilated (created) in the hard process, where the bound on energy loss applies. In this case the induced gluon radiation reduces to purely initial (final) state radiation, and the fully coherent part of the radiation cancels out, leaving only a contribution from $t_f \\lesssim L$. As is well-known, in the high energy limit the resulting parton energy loss is independent of $E$ (neglecting logarithms) and proportional to $L^2$.

Stéphane Peigné; François Arleo; Rodion Kolevatov

2014-02-07

58

Radiation effects and annealing kinetics in crystalline silicates, phosphates and complex Nb-Ta-Ti oxides. FInal Report  

SciTech Connect

Interaction of heavy particles (alpha-recoil nuclei, fission fragments, implanted ions) with ceramics is complex because they have a wide range of structure types, complex compositions and chemical bonding is variable. Radiation damage can produce diverse results, but most commonly, crystalline periodic materials become either polycrystalline or aperiodic (metamict state). We studied the transition from crystalline to aperiodic state in natural materials that have been damaged by alpha recoil nuclei in the U and Th decay series and in synthetic, analogous structure types which have been amorphized by ion implantation. Transition from crystalline to aperiodic was followed by analysis of XRD, high resolution TEM, and EXAFS/XANE spectroscopy. Use of these techniques with increasing dose provided data on an increasing finer scale as the damage process progressed.

Ewing, R.C.

1987-08-10

59

Crystallinity in starch bioplastics  

Microsoft Academic Search

Thermoplastic starch (TPS) materials have been prepared by kneading, extrusion, compression moulding and injection moulding of several native starches with the addition of glycerol as a plasticizer. Two types of crystallinity can be distinguished in TPS directly after processing: (i) residual crystallinity: native A-, B- or C-type crystallinity caused by incomplete melting of starch during processing; (ii) processing-induced crystallinity: amylose

Jeroen J. G. van Soest; S. H. D. Hulleman; D. de Wit; J. F. G. Vliegenthart

1996-01-01

60

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

61

Eicosapentaenoic acid inhibits glucose-induced membrane cholesterol crystalline domain formation through a potent antioxidant mechanism.  

PubMed

Lipid oxidation leads to endothelial dysfunction, inflammation, and foam cell formation during atherogenesis. Glucose also contributes to lipid oxidation and promotes pathologic changes in membrane structural organization, including the development of cholesterol crystalline domains. In this study, we tested the comparative effects of eicosapentaenoic acid (EPA), an omega-3 fatty acid indicated for the treatment of very high triglyceride (TG) levels, and other TG-lowering agents (fenofibrate, niacin, and gemfibrozil) on lipid oxidation in human low-density lipoprotein (LDL) as well as membrane lipid vesicles prepared in the presence of glucose (200mg/dL). We also examined the antioxidant effects of EPA in combination with atorvastatin o-hydroxy (active) metabolite (ATM). Glucose-induced changes in membrane structural organization were measured using small angle x-ray scattering approaches and correlated with changes in lipid hydroperoxide (LOOH) levels. EPA was found to inhibit LDL oxidation in a dose-dependent manner (1.0-10.0µM) and was distinguished from the other TG-lowering agents, which had no significant effect as compared to vehicle treatment alone. Similar effects were observed in membrane lipid vesicles exposed to hyperglycemic conditions. The antioxidant activity of EPA, as observed in glucose-treated vesicles, was significantly enhanced in combination with ATM. Glucose treatment produced highly-ordered, membrane-restricted, cholesterol crystalline domains, which correlated with increased LOOH levels. Of the agents tested in this study, only EPA inhibited glucose-induced cholesterol domain formation. These data demonstrate that EPA, at pharmacologic levels, inhibits hyperglycemia-induced changes in membrane lipid structural organization through a potent antioxidant mechanism associated with its distinct, physicochemical interactions with the membrane bilayer. PMID:25449996

Mason, R Preston; Jacob, Robert F

2015-02-01

62

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

63

Radiation-induced instability and its relation to radiation carcinogenesis  

NASA Technical Reports Server (NTRS)

PURPOSE: A model that identifies radiation-induced genetic instability as the earliest cellular event in the multi-step sequence leading to radiation-induced cancer was previously proposed. In this paper ongoing experiments are discussed which are designed to test this model and its predictions in mouse mammary epithelial cells. RESULTS: Several lines of evidence are presented that appear to support this model: first, the development of delayed mutations in p53 following irradiation in altered growth variants; secondly, the high frequencies for the induction of both instability and transformation following irradiation in mammary epithelial cells; and finally, the demonstration that susceptibility to the induction of cytogenetic instability is a heritable trait that correlates with susceptibility to transformation and radiation-induced mammary cancer. Mice resistant to transformation and mammary cancer development are also resistant to the development of instability after irradiation. In contrast, mice sensitive to transformation and cancer are also sensitive to the development of cytogenetic instability. CONCLUSIONS: Data from this laboratory and from the studies cited above suggest a specific, and perhaps unique, role for radiation-induced instability as a critical early event associated with initiation of the carcinogenic process.

Ullrich, R. L.; Ponnaiya, B.

1998-01-01

64

Gemcitabine-induced radiation recall myositis.  

PubMed

Radiation recall is an uncommon phenomenon in which administration of a chemotherapeutic agent induces an acute inflammatory reaction in previously irradiated tissues, often weeks to years after completion of radiotherapy. This entity is well known to medical and radiation oncologists, however only three cases have been reported in radiology journals. We present a case of gemcitabine-induced radiation recall that manifested as myositis with associated dermatitis in the posterior thigh of a patient with remote history of localized radiotherapy for biopsy-proven breast cancer metastasis. We also present a brief literature review to update the topic of radiation recall in imaging, and emphasize the importance of knowledge of this phenomenon when considering the differential diagnosis of myositis/dermatitis in a patient who has received cancer treatment. PMID:25193536

Delavan, Joshua Adam; Chino, Junzo P; Vinson, Emily N

2015-03-01

65

Radiation induced conductivity in space dielectric materials  

SciTech Connect

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{sup ®} 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{sup ®} 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. [DESP, The French Aerospace Lab, 2 avenue Edouard Belin, 31055 Toulouse (France); Energie, SUPELEC, 3 rue Joliot Curie, 91192 Gif sur Yvette (France); CNES, 18 avenue Edouard Belin, 31401 Toulouse (France); Paulmier, T., E-mail: thierry.paulmier@onera.fr; Belhaj, M.; Dirassen, B. [DESP, The French Aerospace Lab, 2 avenue Edouard Belin, 31055 Toulouse (France); Molinie, P. [Energie, SUPELEC, 3 rue Joliot Curie, 91192 Gif sur Yvette (France); Payan, D.; Balcon, N. [CNES, 18 avenue Edouard Belin, 31401 Toulouse (France)

2014-01-21

66

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

67

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. PMID:22348250

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

2013-01-01

68

Quercetin Inhibits Radiation-Induced Skin Fibrosis  

PubMed Central

Radiation induced fibrosis of the skin is a late toxicity that may result in loss of function due to reduced range of motion and pain. The current study sought to determine if oral delivery of quercetin mitigates radiation-induced cutaneous injury. Female C3H/HeN mice were fed control chow or quercetin-formulated chow (1% by weight). The right hind leg was exposed to 35 Gy of X rays and the mice were followed serially to assess acute toxicity and hind leg extension. Tissue samples were collected for assessment of soluble collagen and tissue cytokines. Human and murine fibroblasts were subjected to clonogenic assays to determine the effects of quercetin on radiation response. Contractility of fibroblasts was assessed with a collagen contraction assay in the presence or absence of quercetin and transforming growth factor-? (TGF-?). Western blotting of proteins involved in fibroblast contractility and TGF-? signaling were performed. Quercetin treatment significantly reduced hind limb contracture, collagen accumulation and expression of TGF-? in irradiated skin. Quercetin had no effect on the radioresponse of fibroblasts or murine tumors, but was capable of reducing the contractility of fibroblasts in response to TGF-?, an effect that correlated with partial stabilization of phosphorylated cofilin. Quercetin is capable of mitigating radiation induced skin fibrosis and should be further explored as a therapy for radiation fibrosis. PMID:23819596

Horton, Jason A.; Li, Fei; Chung, Eun Joo; Hudak, Kathryn; White, Ayla; Krausz, Kristopher; Gonzalez, Frank; Citrin, Deborah

2013-01-01

69

Radiation-induced degradation of DNA bases  

Microsoft Academic Search

Radio-induced degradation of DNA involves radical processes. A series of lesions among the major bases degradation products has been measured in isolated DNA exposed to gamma radiation in aerated aqueous solution. Degradation can be accounted for by the formation of hydroxyl radicals upon radiolysis of water (indirect effect). The four bases are degraded in high yield. Direct effect has been

T. Douki; T. Delatour; R. Martini; J. Cadet

1999-01-01

70

Nuclear Radiation Induced Noise in Infrared Detectors  

Microsoft Academic Search

A model for calculating the rate and amplitude of gamma ionization events in infrared detectors is presented. Several simplifying approximations to the actual, complex physical situation are applied in the model, thereby allowing an exact analytical formulation of the problem. Experimental measurements of nuclear-radiation induced noise pulse-height distributions and event rates are compared to predictions made using the model. Comparisons

J. C. Pickel; M. D. Petroff

1975-01-01

71

Nuclear radiation induced noise in infrared detectors  

Microsoft Academic Search

A model for calculating the rate and amplitude of gamma ionization events in infrared detectors is presented. Several simplifying approximations to the actual, complex physical situation are applied in the model, thereby allowing an exact analytical formulation of the problem. Experimental measurements of nuclear-radiation induced noise pulse-height distributions and event rates are compared to predictions made using the model. Comparisons

J. C. Pickel; M. D. Petroff

1975-01-01

72

Radiation-induced meningiomas in pediatric patients  

SciTech Connect

Radiation-induced meningiomas rarely have latency periods short enough from the time of irradiation to the clinical presentation of the tumor to present in the pediatric patient. Three cases of radiation-induced intracranial meningiomas in pediatric patients are presented. The first involved a meningioma of the right frontal region in a 10-year-old boy 6 years after the resection and irradiation of a 4th ventricular medulloblastoma. Review of our pediatric tumor cases produced a second case of a left temporal fossa meningioma presenting in a 15-year-old boy with a history of irradiation for retinoblastoma at age 3 years and a third case of a right frontoparietal meningioma in a 15-year-old girl after irradiation for acute lymphoblastic leukemia. Only three cases of meningiomas presenting in the pediatric age group after radiation therapy to the head were detected in our review of the literature.

Moss, S.D.; Rockswold, G.L.; Chou, S.N.; Yock, D.; Berger, M.S.

1988-04-01

73

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

74

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

75

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

76

Radiation-induced brain injury: A review  

PubMed Central

Approximately 100,000 primary and metastatic brain tumor patients/year in the US survive long enough (>6 months) to experience radiation-induced brain injury. Prior to 1970, the human brain was thought to be highly radioresistant; the acute CNS syndrome occurs after single doses >30 Gy; white matter necrosis occurs at fractionated doses >60 Gy. Although white matter necrosis is uncommon with modern techniques, functional deficits, including progressive impairments in memory, attention, and executive function have become important, because they have profound effects on quality of life. Preclinical studies have provided valuable insights into the pathogenesis of radiation-induced cognitive impairment. Given its central role in memory and neurogenesis, the majority of these studies have focused on the hippocampus. Irradiating pediatric and young adult rodent brains leads to several hippocampal changes including neuroinflammation and a marked reduction in neurogenesis. These data have been interpreted to suggest that shielding the hippocampus will prevent clinical radiation-induced cognitive impairment. However, this interpretation may be overly simplistic. Studies using older rodents, that more closely match the adult human brain tumor population, indicate that, unlike pediatric and young adult rats, older rats fail to show a radiation-induced decrease in neurogenesis or a loss of mature neurons. Nevertheless, older rats still exhibit cognitive impairment. This occurs in the absence of demyelination and/or white matter necrosis similar to what is observed clinically, suggesting that more subtle molecular, cellular and/or microanatomic modifications are involved in this radiation-induced brain injury. Given that radiation-induced cognitive impairment likely reflects damage to both hippocampal- and non-hippocampal-dependent domains, there is a critical need to investigate the microanatomic and functional effects of radiation in various brain regions as well as their integration at clinically relevant doses and schedules. Recently developed techniques in neuroscience and neuroimaging provide not only an opportunity to accomplish this, but they also offer the opportunity to identify new biomarkers and new targets for interventions to prevent or ameliorate these late effects. PMID:22833841

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

2012-01-01

77

Photo induced minority carrier annihilation at crystalline silicon surface in metal oxide semiconductor structure  

NASA Astrophysics Data System (ADS)

We report the properties of features of photo induced minority carrier annihilation at the silicon surface in a metal-oxide-semiconductor (MOS) structure using 9.35 GHz microwave transmittance measurement. 7 ? cm n-type 500-µm-thick crystalline silicon substrates coated with 100-nm-thick thermally grown SiO2 layers were prepared. Part of the SiO2 at the rear surface was removed. Al electrode bars were formed at the top and rear surfaces to form the structures Al/SiO2/Si/SiO2/Al and Al/SiO2/Si/Al. 635 nm light illumination onto the top surface caused photo induced carriers to be in one side of the silicon region of the Al electrode bar of the structure Al/SiO2/Si/SiO2/Al. Microwave transmittance was measured on the other side of the silicon region of the Al electrode bars. The measurement and analysis of microwave absorption by photo induced carriers laterally diffusing across the silicon region coated with Al electrodes revealed a change in the carrier recombination velocity at the silicon surface with the bias voltage applied onto the top Al electrode. The applied bias voltages of +2.0 and -2.2 V gave peaks at surface recombination velocities of 83 and 86 cm/s, respectively, for the sample structure Al/SiO2/Si/SiO2/Al, while it was 44 cm/s under the bias-free condition. A peak surface recombination velocity of 81 cm/s was only observed at a bias voltage of -2.0 V for the sample structure Al/SiO2/Si/Al.

Sameshima, Toshiyuki; Furukawa, Jun; Nakamura, Tomohiko; Shigeno, Satoshi; Node, Tomohito; Yoshidomi, Shinya; Hasumi, Masahiko

2014-03-01

78

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

79

Interference Phenomena in Medium Induced Radiation  

E-print Network

We consider the interference pattern for the medium-induced gluon radiation produced by a color singlet quark-antiquark antenna embedded in a QCD medium with size $L$ and `jet quenching' parameter $\\hat q$. Within the BDMPS-Z regime, we demonstrate that, for a dipole opening angle $\\theta_{q\\bar q} \\gg\\theta_c\\equiv {2}/{\\sqrt{\\hat q L^3}}$, the interference between the medium--induced gluon emissions by the quark and the antiquark is suppressed with respect to the direct emissions. This is so since direct emissions are delocalized throughout the medium and thus yield contributions proportional to $L$ while interference occurs only between emissions at early times, when both sources remain coherent. Thus, for $\\tqq \\gg\\theta_c$, the medium-induced radiation is the sum of the two spectra individually produced by the quark and the antiquark, without coherence effects like angular ordering. For $\\tqq \\ll\\theta_c$, the medium--induced radiation vanishes.

Jorge Casalderrey-Solana; Edmond Iancu

2011-06-20

80

Ionizing radiation-induced diseases in Korea.  

PubMed

Radiation risk has become well known through epidemiological studies of clinically or occupationally exposed populations, animal experiments, and in vitro studies; however, the study of radiation related or induced disease has been limited in Korea. This study is to find the level of occupational radiation exposure for various kinds of accidents, compensated occupational diseases, related studies, and estimations on future occupational disease risks. Research data of related institutions were additionally investigated. About 67% of 62,553 radiation workers had no exposure or less than 1.2 mSv per year. The 5 reported cases on radiation accident patients in Korea occurred during nondestructive testing. According to the recent rapid increase in the number of workers exposed to radiation, a higher social recognition of cancer, and an increasing cancer mortality rate, it is expected that occupational disease compensation will rapidly increase as well. Therefore, it is important to develop scientific and objective decision methods, such as probability of causation and screening dose in the establishment of an exposure and health surveillance system. PMID:21258594

Jin, Young-Woo; Jeong, Meeseon; Moon, Kieun; Jo, Min-Heui; Kang, Seong-Kyu

2010-12-01

81

Ionizing Radiation-induced Diseases in Korea  

PubMed Central

Radiation risk has become well known through epidemiological studies of clinically or occupationally exposed populations, animal experiments, and in vitro studies; however, the study of radiation related or induced disease has been limited in Korea. This study is to find the level of occupational radiation exposure for various kinds of accidents, compensated occupational diseases, related studies, and estimations on future occupational disease risks. Research data of related institutions were additionally investigated. About 67% of 62,553 radiation workers had no exposure or less than 1.2 mSv per year. The 5 reported cases on radiation accident patients in Korea occurred during nondestructive testing. According to the recent rapid increase in the number of workers exposed to radiation, a higher social recognition of cancer, and an increasing cancer mortality rate, it is expected that occupational disease compensation will rapidly increase as well. Therefore, it is important to develop scientific and objective decision methods, such as probability of causation and screening dose in the establishment of an exposure and health surveillance system. PMID:21258594

Jeong, Meeseon; Moon, Kieun; Jo, Min-Heui; Kang, Seong-Kyu

2010-01-01

82

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

PubMed Central

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.; O’Hare, Dermot; Austyn, Jonathan M.

2014-01-01

83

Radiation induced fracture of the scapula  

SciTech Connect

A case of radiation induced osteonecrosis resulting in a fracture of the scapula in a 76-yr-old female patient with a history of breast carcinoma is presented. Diagnostic imaging, laboratory recommendations and clinical findings are discussed along with an algorithm for the safe management of patients with a history of cancer and musculoskeletal complaints. This case demonstrates the necessity of a thorough investigation of musculoskeletal complaints in patients with previous bone-seeking carcinomas.

Riggs, J.H. III; Schultz, G.D.; Hanes, S.A. (Los Angeles College of Chiropractic, Whittier, CA (USA))

1990-10-01

84

Radiation-induced morphea - a literature review.  

PubMed

Radiation-induced morphea (RIM) is a rare and under-recognized skin complication of radiotherapy. It is commonly wrongly diagnosed as other dermatological conditions or malignancy because of similar clinical characteristics. This literature review analyses 66 cases that have been reported in the literature since 1989. The clinical appearance often includes pain and disfiguration of affected area, which may influence the patient's quality of life. There is no clear connection between the radiotherapy dose, the fractionation scheme, the use of a boost, age, the presence of other dermatological conditions or other connective tissue diseases and the occurrence of RIM. Its pathogenesis is still unclear, but several theories are proposed to explain this phenomenon. The available data suggest that the abnormally high secretion of some cytokines (interleukin 4, interleukin 5, transforming growth factor) induced by radiation causes an extensive fibrosis after an activation of fibroblasts. Histological confirmation is crucial in distinguishing RIM from similar-looking diseases, such as chronic radiation dermatitis, cancer recurrence, radiation, recall dermatitis, new carcinoma or cellulitis. There is no clear treatment regimen for this condition. Clinical outcome after therapy is often unsatisfactory. The commonly used methods and agents include: topical and systemic steroids, calcineurin inhibitors, systemic immunosuppressants including methotrexate, tacrolimus, heparin, hyaluronidase, phototherapy (UVA, UVA1, UVB, PUVA), systemic antibiotics, imiquimod, mycophenolate mofetil, photophoresis. The differential diagnosis is challenging and requires a multidisciplinary approach to avoid misdiagnosis and to plan appropriate treatment. PMID:25174551

Spalek, M; Jonska-Gmyrek, J; Ga?ecki, J

2015-02-01

85

Amorphous silicon\\/crystalline silicon heterojunctions for nuclear radiation detector applications  

Microsoft Academic Search

Results on the characterization of the electrical properties of amorphous silicon films for the three different growth methods, RF sputtering, PECVD, and LPCVD are reported. The performance of these a-Si films as heterojunctions on high resistivity p-type and n-type crystalline silicon is examined by measuring the noise, leakage current and the alpha particle response of 5 mm diameter detector structures.

J. T. Walton; W. S. Hong; P. N. Luke; N. W. Wang; F. P. Ziemba

1997-01-01

86

Amorphous silicon\\/crystalline silicon heterojunctions for nuclear radiation detector applications  

Microsoft Academic Search

Results on the characterization of the electrical properties of amorphous silicon films for the three different growth methods, RF sputtering, PECVD, and LPCVD are reported. The performance of these a-Si films as heterojunctions on high resistivity p-type and n-type crystalline silicon is examined by measuring the noise, leakage current and the alpha particle response of 5 mm diameter detector structures.

J. T. Walton; W. S. Hong; P. N. Luke; N. W. Wang; F. P. Ziemba

1996-01-01

87

The ?A66-80 peptide interacts with soluble ?-crystallin and induces its aggregation and precipitation: a contribution to age-related cataract formation.  

PubMed

Formation of protein aggregates in the aging eye lens has been shown to correlate with progressive accumulation of specific low-molecular weight (LMW) peptides derived from crystallins. Prominent among the LMW fragments is ?A66-80, a peptide derived from ?A-crystallin and present at higher concentrations in the water-insoluble nuclear fractions of the aging lens. The ?A66-80 peptide has amyloid-like properties and preferentially insolubilizes ?-crystallin from soluble lens fractions. However, the specific interactions and mechanisms by which the peptide induces ?-crystallin aggregation have not been delineated. To gain insight into the mechanisms of peptide-induced aggregation, we investigated the interactions of the peptide with ?-crystallin by various biochemical approaches. The peptide weakens ?-crystallin chaperone ability and drastically promotes ?-crystallin aggregation via the formation of insoluble peptide-protein complexes through transient intermediates. 4,4'-Dianilino-1,1'-binaphthyl-5,5'-disulfonic acid studies suggest that the peptide induces changes in the hydrophobicity of ?-crystallin that could trigger the formation and growth of aggregates. The peptide-?-crystallin aggregates were found to be resistant to dissociation by high ionic strengths, whereas guanidinium hydrochloride and urea were effective dissociating agents. We conclude that the ?A66-80 peptide forms a hydrophobically driven, stable complex with ?-crystallin and reduces its solubility. Using isotope-labeled chemical cross-linking and mass spectrometry, we show that the peptide binds to multiple sites, including the chaperone site, the C-terminal extension, and subunit interaction sites in ?B-crystallin, which may explain the antichaperone property of the peptide and the consequential age-related accumulation of aggregated proteins. Thus, the ?-crystallin-derived peptide could play a role in the pathogenesis of cataract formation in the aging lens. PMID:23631441

Kannan, Rama; Santhoshkumar, Puttur; Mooney, Brian P; Sharma, K Krishna

2013-05-28

88

? A66-80 Peptide Interacts with Soluble ?-crystallin and Induces its Aggregation and Precipitation: A Contribution to Age-related Cataract Formation  

PubMed Central

Formation of protein aggregates in the aging eye lens has been shown to correlate with progressive accumulation of specific low molecular weight (LMW) peptides derived from crystallins. Prominent among the LMW fragments is ?A66-80, a peptide derived from ?A-crystallin and present in increased concentrations in the water-insoluble (WIS) nuclear fractions of the aging lens. The ?A66-80 peptide has amyloid-like properties and preferentially insolubilizes ?-crystallin from soluble lens fractions. However, the specific interactions and mechanisms by which the peptide induces ?-crystallin aggregation have not been delineated. To gain insights into the mechanisms of peptide-induced aggregation, we investigated the peptide interactions with ?-crystallin by various biochemical approaches. The peptide diminishes ?-crystallin chaperone ability and drastically promotes ?-crystallin aggregation by formation of insoluble peptide-protein complexes through transient intermediates. Bis-ANS studies suggest that the peptide induces changes in hydrophobicity of ?-crystallin that could trigger the formation and growth of aggregates. The peptide-?-crystallin aggregates were found to be resistant to dissociation by high ionic strength, whereas guanidium hydrochloride and urea were effective dissociating agents. We conclude that the ?A66-80 peptide forms a hydrophobically driven, stable complex with ?-crystallin and reduces its solubility. Using isotope-labeled chemical crosslinking and mass spectrometry, we show that the peptide binds to multiple sites, including the chaperone site, C-terminal extension and subunit interaction sites in ?B-crystallin, which may explain the anti-chaperone property of the peptide and the consequential age-related accumulation of aggregated proteins. Thus, the ?-crystallin-derived peptide could play a role in the pathogenesis of cataract formation in the aging lens. PMID:23631441

Kannan, Rama; Santhoshkumar, Puttur; Mooney, Brian P.; Sharma, K. Krishna

2013-01-01

89

Shear-Induced Mixing Governs Codeformation of Crystalline-Amorphous Nanolaminates  

NASA Astrophysics Data System (ADS)

Deformation of ductile crystalline-amorphous nanolaminates is not well understood due to the complex interplay of interface mechanics, shear banding, and deformation-driven chemical mixing. Here we present indentation experiments on 10 nm nanocrystalline Cu-100 nm amorphous CuZr model multilayers to study these mechanisms down to the atomic scale. By using correlative atom probe tomography and transmission electron microscopy we find that crystallographic slip bands in the Cu layers coincide with noncrystallographic shear bands in the amorphous CuZr layers. Dislocations from the crystalline layers drag Cu atoms across the interface into the CuZr layers. Also, crystalline Cu blocks are sheared into the CuZr layers. In these sheared and thus Cu enriched zones the initially amorphous CuZr layer is rendered into an amorphous plus crystalline nanocomposite.

Guo, Wei; Jägle, Eric A.; Choi, Pyuck-Pa; Yao, Jiahao; Kostka, Aleksander; Schneider, Jochen M.; Raabe, Dierk

2014-07-01

90

Radiation-Induced Spinal Cord Hemorrhage (Hematomyelia)  

PubMed Central

Intraspinal hemorrhage is very rare and intramedullary hemorrhage, also called hematomyelia, is the rarest form of intraspinal hemorrhage, usually related to trauma. Spinal vascular malformations such intradural arteriovenous malformations are the most common cause of atraumatic hematomyelia. Other considerations include warfarin or heparin anticoagulation, bleeding disorders, spinal cord tumors. Radiation-induced hematomyelia of the cord is exceedingly rare with only one case in literature to date. We report the case of an 8 year old girl with Ewing’s sarcoma of the thoracic vertebra, under radiation therapy, presenting with hematomyelia. We describe the clinical course, the findings on imaging studies and the available information in the literature. Recognition of the clinical pattern of spinal cord injury should lead clinicians to perform imaging studies to evaluate for compressive etiologies. PMID:25568739

Agarwal, Amit; Kanekar, Sangam; Thamburaj, Krishnamurthy; Vijay, Kanupriya

2014-01-01

91

Countermeasures for Space Radiation Induced Malignancies and Acute Biological Effects  

Microsoft Academic Search

The hypothesis being evaluated in this research program is that control of radiation induced oxidative stress will reduce the risk of radiation induced adverse biological effects occurring as a result of exposure to the types of radiation encountered during space travel. As part of this grant work, we have evaluated the protective effects of several antioxidants and dietary supplements and

Ann Kennedy

2008-01-01

92

Low energy oxygen implantation induced improved crystallinity and optical properties of surface modified ZnO single crystals  

NASA Astrophysics Data System (ADS)

We report on the low energy oxygen implantation induced improvement in crystallinity and optical properties of surface modified ZnO single crystals. Undoped ZnO (0 0 0 1) single crystal wafers are implanted with 100 keV oxygen ions at a dose of 5 × 10 13 and 5 × 10 14 cm -2 and subsequently annealed at 500 and 600 °C in oxygen ambient. The as-implanted and annealed ZnO wafers are studied by Rutherford back scattering spectrometry (RBS), channeling, Raman, photoluminescence (PL), and Fourier transform infrared spectroscopy (FTIR). Channeling studies show a relatively high ?min (>20%) in the virgin ZnO wafer. After implantation and two-step annealing, RBS studies show improved crystallinity. Raman line width analysis for the E2high mode indicates reduction in strain in the annealed samples as compared to the virgin ZnO wafer. As-implanted samples show drastic quenching of the near band-edge (NBE) PL band due to defects created by the implantation. However, after two-step annealing, the low-dose implanted sample show a five-fold increase in intensity ratio of NBE band (376 nm) to defect related broad band (˜530 nm) at room temperature. Implantation induced changes in the composition and improved crystallinity in the near surface region is accounted for the major improvement in the PL emission.

Giri, P. K.; Kumari, Satchi; Goswami, D. K.

2009-10-01

93

Radiation induced micrencephaly in guinea pigs  

SciTech Connect

A brain weight deficit of about 70 mg was induced at doses of approximately 75-mGy and a deficit of 60 mg was induced at 100 mGy. This confirms the effects projected and observed by Wanner and Edwards. Although the data do not demonstrate a clear dose-response relationship between the 75-mGy and 100-mGy groups, the data are statistically consistent with a dose-response effect because of the overlapping confidence intervals. The lack of a statistically significant observation is most likely related to the small difference in doses and the limited numbers of animals examined. There are several factors that can influence the brain weight of guinea pig pups, such as caging and housing conditions, the sex of the animal, and litter size. These should be taken into account for accurate analysis. Dam weight did not appear to have a significant effect. The confirmation of a micrencephalic effect induced x rays at doses of 75-mGy during this late embryonic stage of development is consistent with the findings of small head size induced in those exposed prior to the eight week of conception at Hiroshima. This implies a mechanism for micrencephaly different from those previously suggested and lends credence to a causal relation between radiation and small head size in humans at low doses as reported by Miller and Mulvihill. 16 refs., 13 tabs.

Wagner, L.K.; Johnston, D.A.; Felleman, D.J.

1991-01-01

94

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

95

Generation of high-amplitude soliton waves in crystalline materials of different dimensions under high radiative, dynamic, and temperature loads  

SciTech Connect

It is shown that beams of high-amplitude supersonic breather solitons, phonons, and subsonic excitations of new type (torsions) are generated in crystalline materials of different dimensions under high radiative and dynamic loads near the stability threshold. The dispersion dependences of solitons and phonons in 1D crystals are presented. It is shown that, in 2D crystals beams consisting of six or two (depending on the bombarding particle direction), breather solitons are generated and propagate in certain crystallographic directions. The masses of soliton excitations as particles (coupled complexes of massless phonons) have been determined. It is shown that the subsonic soliton waves of a new type with torsion atomic vibrations are generated in 3D nanotubes, along with supersonic soliton waves of longitudinal vibrations.

Dubovsky, O. A., E-mail: dubov@ippe.ru; Orlov, A. V. [Leipunsky Institute for Physics and Power Engineering, State Scientific Center of the Russian Federation (Russian Federation)

2011-12-15

96

Guanidine hydrochloride induced reversible dissociation and denaturation of duck delta2-crystallin.  

PubMed

The tetrameric delta2-crystallin from duck lens exhibits a reversible dissociation-denaturation process in solutions containing guanidine hydrochloride (GdnHCl). Sigmoidal or biphasic curves for the dissociation/denaturation processes, obtained using different methods of structural analysis, as a function of GdnHCl concentration were not coincidental with each other. delta2-crystallin in 0.91 M GdnHCl existed primarily as a monomer, which had no endogenous argininosuccinate lyase activity. After dilution of the GdnHCl-treated protein, the monomers reassociated into tetramers with concomitant recovery of enzyme activity. The sigmoidal recovery of enzyme activity demonstrates a cooperative hysteretic reactivation process. When the concentration of GdnHCl was higher than 1.2 M, various partially unfolded soluble forms of delta2-crystallin were produced from the dissociated monomers as shown by size-exclusion chromatography. The formation of a partially unfolded intermediate during the dissociation-denaturation process is proposed. PMID:10866796

Lee, H J; Chang, G G

2000-07-01

97

Radiation-induced uterine changes: MR imaging  

SciTech Connect

To assess the capability of magnetic resonance (MR) imaging to demonstrate postirradiation changes in the uterus, MR studies of 23 patients who had undergone radiation therapy were retrospectively examined and compared with those of 30 patients who had not undergone radiation therapy. MR findings were correlated with posthysterectomy histologic findings. In premenopausal women, radiation therapy induced (a) a decrease in uterine size demonstrable as early as 3 months after therapy ended; (b) a decrease in signal intensity of the myometrium on T2-predominant MR images, reflecting a significant decrease in T2 relaxation time, demonstrable as early as 1 month after therapy; (c) a decrease in thickness and signal intensity of the endometrium demonstrable on T2-predominant images 6 months after therapy; and (d) loss of uterine zonal anatomy as early as 3 months after therapy. In postmenopausal women, irradiation did not significantly alter the MR imaging appearance of the uterus. These postirradiation MR changes in both the premenopausal and postmenopausal uteri appeared similar to the changes ordinarily seen on MR images of the nonirradiated postmenopausal uterus.

Arrive, L.; Chang, Y.C.; Hricak, H.; Brescia, R.J.; Auffermann, W.; Quivey, J.M.

1989-01-01

98

Atomic structure and thermally induced transformation of the crystalline BaO/Si(100) junction  

NASA Astrophysics Data System (ADS)

Atomic structure of interfaces between oxide layers and semiconductors is usually challenging to probe because of its buried nature. Here, we present a synchrotron photoemission approach to unveil the interface structure of BaO/Si(100), a prototype model of crystalline-oxide/semiconductor junctions, and demonstrate that such interface outspreads over four Si atomic planes and contains five different crystal sites for Si atoms, including three Si-O bonding sites. An atomic model is suggested for this system. Heating enhances Si diffusion and oxidation, but the junction still remains crystalline at 500 °C, promising potential for integration of III-V films and Si(100).

Kuzmin, M.; Laukkanen, P.; Punkkinen, M. P. J.; Yasir, M.; Tuominen, M.; Dahl, J.; Lâng, J. J. K.; Mäkelä, J.; Kokko, K.

2014-12-01

99

The Formation of Crystalline Dust in AGB Winds from Binary Induced Spiral Shocks  

E-print Network

As stars evolve along the Asymptotic Giant Branch, strong winds are driven from the outer envelope. These winds form a shell, which may ultimately become a planetary nebula. Many planetary nebulae are highly asymmetric, hinting at the presence of a binary companion. Some post-Asymptotic Giant Branch objects are surrounded by torii of crystalline dust, but there is no generally accepted mechanism for annealing the amorphous grains in the wind to crystals. In this Letter, we show that the shaping of the wind by a binary companion is likely to lead to the formation of crystalline dust in the orbital plane of the binary.

R. G. Edgar; J. Nordhaus; E. Blackman; A. Frank

2007-09-14

100

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

101

The theory of radiation emission by relativistic particles in amorphous and crystalline media  

NASA Astrophysics Data System (ADS)

Consideration is given to the effect of multiple scattering and polarization on the intensity of low-frequency coherent radiation in crystal and amorphous media, with emphasis on the radiation emitted by relativistic particles. The results of Migdal (1954) and Ter-Mikaelian (1953) concerning the effect of multiple scattering and polarization of the medium on bremsstrahlung of fast particles in amorphous media were reproduced using a continual integration. A formula was derived to describe the effect of multiple particle scattering by atomic chains. The effect of polarization on the intensity of the coherent radiation emitted by ultrarelativistic particles in a crystal is also described. It is shown that the effect of multiple scattering on the emission range of photons in a crystal may be significant at much lower particles than in an amorphous medium. The possibility of investigating the Landau-Pokerantchuk effect on accelerators is also briefly discussed.

Laskin, N. V.; Mazmanishvili, A. S.; Nasonov, N. N.; Shulga, N. F.

1985-09-01

102

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

103

A STUDY ON MICROWAVE INSTABILITY INDUCED RADIATION.  

SciTech Connect

It has been shown in the context of a solvable model that the microwave instability can be described in terms of ''coherent states'' [1]. Building on this model, we first show that the simplicity of the model arises from the fact that the key integral-differential equation can be reduced to the Karhunen-Loeve equation of the theory of stochastic processes. We present results on the correlation functions of the electric field. In particular, for the second order correlation function, we show that a relation akin to the Hanbury Brown-Twiss correlation holds for the coherent states of the microwave-instability induced radiation. We define an entropy-like quantity and we introduce a Wigner distribution function representation.

MURPHY,J.B.; WANG,J.M.

1999-03-29

104

Analysis of radiation pressure induced nonlinear optofluidics.  

PubMed

We analyze two nonlinear optofluidic processes where nonlinearity is induced by the interplay between optical field and liquid interface. Specifically, guided optical waves generate radiation pressure on the liquid interface, which can in turn distort the liquid interface and modify the properties of the optical field. In the first example, we discuss the feasibility of nonlinear optofluidic solitons, where optical field is governed by the nonlinear Schrödinger equation and nonlinearity is effectively determined by liquid properties. Then, we analyze a nonlinear optofluidic process associated with a high quality (Q) factor whispering gallery mode (WGM) in a liquid droplet. Similar to Kerr effects, the WGM can produce a frequency shift proportional to the WGM power. Using liquid properties that are experimentally attainable, we find that it may only take a few photons to generate measurable WGM resonance shift. Such a possibility may eventually lead to nonlinear optics at single photon energy level. PMID:25402127

Xu, Yong; Zhang, Peng; Jung, Sunghwan; Lee, Aram

2014-11-17

105

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

106

Alpha-decay-induced fracturing in zircon - The transition from the crystalline to the metamict state  

NASA Technical Reports Server (NTRS)

Zonation due to alpha-decay damage in a natural single crystal of zircon from Sri Lanka is discussed. The zones vary in thickness on a scale from one to hundreds of microns. The uranium and thorium concentrations vary from zone to zone such that the alpha decay dose is between 0.2 x 10 to the 16th and 0.8 x 10 to the 16th alpha-events per milligram. The transition from the crystalline to the aperiodic metamict state occurs over this dose range. At doses greater than 0.8 x 10 to the 16th alpha events/mg there is no evidence for long-range order. This type of damage will accumulate in actinide-bearing, ceramic nuclear waste forms. The systematic pattern of fractures would occur in crystalline phases that are zoned with respect to actinide radionuclides.

Chakoumakos, Bryan C.; Murakami, Takashi; Lumpkin, Gregory R.; Ewing, Rodney C.

1987-01-01

107

Microstructural evolution induced by micro-cracking during fast lithiation of single-crystalline silicon  

E-print Network

-Bum Kim a,d , Hyunchul Roh a , Se-Hee Lee c , Kyu Hwan Oh a , Joost J. Vlassak b,* a Department-crystalline silicon Yong Seok Choi a,b , Matt Pharr b , Chan Soon Kang a , Seoung-Bum Son a , Seul Cham Kim a , Kee of Materials Science and Engineering, Seoul National University, Seoul 151-742, Republic of Korea b School

108

Excitation Spectrum of Crystalline Tetracene Fluorescence: A Probe for Optically-Induced Singlet-Exciton Fission  

Microsoft Academic Search

The intrinsic fluorescence efficiency of crystalline tetracene depends on the energy of the exiciting light. It decreases for Eexc > 2.48 eV displaying a minimum at Eexc = 2.51 eV which is identical with the energy of the triplet pair state. It is suggested that an optically populated, vibronically excited S 1-state. which is iso-energetic with the triplet pair state

G. Vaubel; H. Baessler

1971-01-01

109

Transcriptional regulation of crystallin, redox, and apoptotic genes by C-Phycocyanin in the selenite-induced cataractogenic rat model  

PubMed Central

Purpose This study was designed to examine the constrictive potential of C-Phycocyanin (C-PC) in regulating changes imposed on gene expression in the selenite-induced cataract model. Methods Wistar rat pups were divided into three groups of eight each. On P10, Group I received an intraperitoneal injection of normal saline. Groups II and III received a subcutaneous injection of sodium selenite (19 ?mol/kg bodyweight); Group III also received an intraperitoneal injection of C-PC (200 mg/kg bodyweight) on P9–14. Total RNA was isolated on P16, and the relative abundance of mRNA of the crystallin structural genes, redox components, and apoptotic cascade were ascertained with real-time PCR with reference to the internal control ?-actin. Results Real-time PCR analysis showed the crystallin genes (?A-, ?B1-, ?D-) and redox cycle components (Cat, SOD-1, Gpx) were downregulated, the apoptotic components were upregulated, and antiapoptotic Bcl-2 was downregulated in Group II. Treatment with 200 mg/kg bodyweight C-PC (Group III) transcriptionally regulated the instability of the expression of these genes, thus ensuring C-PC is a prospective anticataractogenic agent that probably delays the onset and progression of cataractogenesis induced by sodium selenite. Conclusions C-PC treatment possibly prevented cataractogenesis triggered by sodium selenite, by regulating the lens crystallin, redox genes, and apoptotic cascade mRNA expression and thus maintains lens transparency. C-PC may be developed as a potential antioxidant compound applied in the future to prevent and treat age-related cataract.

Kumari, Rasiah Pratheepa; Ramkumar, Srinivasagan; Thankappan, Bency; Natarajaseenivasan, Kalimuthusamy; Balaji, Sadhasivam

2015-01-01

110

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

111

Radiation-induced adaptive response in fish cell lines  

Microsoft Academic Search

There is considerable interest at present in low-dose radiation effects in non-human species. In this study gamma radiation-induced adaptive response, a low-dose radiation effect, was examined in three fish cell lines, (CHSE-214 (Chinook salmon), RTG-2 (rainbow trout) and ZEB-2J (zebrafish)). Cell survival after exposure to direct radiation with or without a 0.1Gy priming dose, was determined using the colony forming

Lorna A. Ryan; Colin B. Seymour; Alicia O'Neill-Mehlenbacher; Carmel E. Mothersill

2008-01-01

112

Towards high efficiency thin-film crystalline silicon solar cells: The roles of light trapping and non-radiative recombinations  

SciTech Connect

Thin-film solar cells based on silicon have emerged as an alternative to standard thick wafers technology, but they are less efficient, because of incomplete absorption of sunlight, and non-radiative recombinations. In this paper, we focus on the case of crystalline silicon (c-Si) devices, and we present a full analytic electro-optical model for p-n junction solar cells with Lambertian light trapping. This model is validated against numerical solutions of the drift-diffusion equations. We use this model to investigate the interplay between light trapping, and bulk and surface recombination. Special attention is paid to surface recombination processes, which become more important in thinner devices. These effects are further amplified due to the textures required for light trapping, which lead to increased surface area. We show that c-Si solar cells with thickness of a few microns can overcome 20% efficiency and outperform bulk ones when light trapping is implemented. The optimal device thickness in presence of light trapping, bulk and surface recombination, is quantified to be in the range of 10–80??m, depending on the bulk quality. These results hold, provided the effective surface recombination is kept below a critical level of the order of 100?cm/s. We discuss the possibility of meeting this requirement, in the context of state-of-the-art techniques for light trapping and surface passivation. We show that our predictions are within the capability of present day silicon technologies.

Bozzola, A., E-mail: angelo.bozzola@unipv.it; Kowalczewski, P.; Andreani, L. C. [Physics Department, University of Pavia and CNISM, via Bassi 6, I-27100 Pavia (Italy)

2014-03-07

113

Matrix induced in-situ growth of crystalline Au nanoparticles for photonic applications  

NASA Astrophysics Data System (ADS)

The authors present a novel in-situ method of fabricating crystalline gold nanoparticles by self-organization. This nanoparticles are grown and modified in a surrounding thin film matrix using two different host materials (YBa2Cu3O7-? and SrTiO3) prepared by a pulsed laser deposition technique. The crystalline Au nanoparticles are formed out of a gold seed layer whereby the thickness of the initial seed layer influences the particle size and their distribution density. As we will show, using a matrix based preparation technique offers several advantages over conventional preparation methods. On the one hand, nanoparticle size and the distribution density can be controlled individually. On the other hand, by choosing an appropriate matrix material as well as suitable growth conditions also the shape of the resulting particles can be modified. Thus, also anisotropic nanoparticles can be prepared without using highly sophisticated methods like electron beam lithography or focused ion beam techniques. As one might have to extract the nanoparticles or at least theirs tips from the surrounding matrix material to realize photonic applications, we will show that an extraction is easily possible by selectively etching the matrix. This extraction process does not influence the particle distribution, i.e. particles can be prepared and extracted at distinct positions on the substrate utilizing a patterning of the Au seed layer. A spectral characterization of extracted as well as embedded particles will be presented based on microspectroscopy as well as on measurements using an integrating sphere.

Katzer, C.; Westerhausen, M.; Naujok, P.; Bernhardt, H.; Schmidl, G.; Fritzsche, W.; Undisz, A.; Drüe, M.; Rettenmayr, M.; Schmidl, F.

2013-09-01

114

Radiation-induced segregation in complex alloys  

SciTech Connect

Radiation-induced segregation (RIS) of alloying elements to the surface during 3 MeV /sup 58/Ni/sup +/ ion bombardment was investigated in alloys of Fe-200Cr-12Ni (at. %) containing controlled additions of Si and Mo. The segregation profiles, determined by Auger electron spectroscopy, show that Ni and Si are enriched, while Cr and Mo are depleted at the irradiated surfaces. The data indicates that the RIS of Ni and Cr are affected by the presence of Mo and Si in the alloy. However, no obvious trends are observed as a function of the minor solute element concentration. The temperature dependence of the RIS of the alloying elements was also investigated. A maximum of segregation at approx. 500/sup 0/C is observed for Si followed by a minimum and then a sharp increase in segregation at temperatures above 600/sup 0/C. The temperature dependence of segregation for Cr, Ni and Mo shows continous increase with temperature in the temperature regime investigated. The void swelling data on these alloys is also presented as a function of temperature and composition. Additions of Si reduce the swelling by affecting both the nucleation and the growth of the voids. The peak swelling temperature for all the alloys containing minor solutes are found to be lower (approx. 50/sup 0/C) than that of the base alloy (peak swelling temperature approx. 660/sup 0/C).

Sethi, V.K.; Okamoto, P.R.

1980-01-01

115

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

116

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. 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

117

Radiation exposure induces inflammasome pathway activation in immune cells.  

PubMed

Radiation exposure induces cell and tissue damage, causing local and systemic inflammatory responses. Because the inflammasome pathway is triggered by cell death and danger-associated molecular patterns, we hypothesized that the inflammasome may signal acute and chronic immune responses to radiation. Using a mouse radiation model, we show that radiation induces a dose-dependent increase in inflammasome activation in macrophages, dendritic cells, NK cells, T cells, and B cells as judged by cleaved caspase-1 detection in cells. Time course analysis showed the appearance of cleaved caspase-1 in cells by day 1 and sustained expression until day 7 after radiation. Also, cells showing inflammasome activation coexpressed the cell surface apoptosis marker annexin V. The role of caspase-1 as a trigger for hematopoietic cell losses after radiation was studied in caspase-1(-/-) mice. We found less radiation-induced cell apoptosis and immune cell loss in caspase-1(-/-) mice than in control mice. Next, we tested whether uric acid might mediate inflammasome activation in cells by treating mice with allopurinol and discovered that allopurinol treatment completely blocked caspase-1 activation in cells. Finally, we demonstrate that radiation-induced caspase-1 activation occurs by a Nod-like receptor family protein 3-independent mechanism because radiation-exposed Nlrp3(-/-) mice showed caspase-1 activation profiles that were indistinguishable from those of wild-type mice. In summary, our data demonstrate that inflammasome activation occurs in many immune cell types following radiation exposure and that allopurinol prevented radiation-induced inflammasome activation. These results suggest that targeting the inflammasome may help control radiation-induced inflammation. PMID:25539818

Stoecklein, Veit M; Osuka, Akinori; Ishikawa, Shizu; Lederer, Madeline R; Wanke-Jellinek, Lorenz; Lederer, James A

2015-02-01

118

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

119

Temperature-induced reversible self-assembly of diphenylalanine peptide and the structural transition from organogel to crystalline nanowires  

PubMed Central

Controlling the self-assembly of diphenylalanine peptide (FF) into various nanoarchitectures has received great amounts of attention in recent years. Here, we report the temperature-induced reversible self-assembly of diphenylalanine peptide to microtubes, nanowires, or organogel in different solvents. We also find that the organogel in isopropanol transforms into crystalline flakes or nanowires when the temperature increases. The reversible self-assembly in polar solvents may be mainly controlled by electronic and aromatic interactions between the FF molecules themselves, which is associated with the dissociation equilibrium and significantly influenced by temperature. We found that the organogel in the isopropanol solvent made a unique transition to crystalline structures, a process that is driven by temperature and may be kinetically controlled. During the heating-cooling process, FF preferentially self-assembles to metastable nanofibers and organogel. They further transform to thermodynamically stable crystal structures via molecular rearrangement after introducing an external energy, such as the increasing temperature used in this study. The strategy demonstrated in this study provides an efficient way to controllably fabricate smart, temperature-responsive peptide nanomaterials and enriches the understanding of the growth mechanism of diphenylalanine peptide nanostructures. PMID:25520600

2014-01-01

120

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

121

Topological phase transition in a topological crystalline insulator induced by finite-size effects  

NASA Astrophysics Data System (ADS)

We study electronic states and topological invariants of (001) films of the topological crystalline insulator (TCI) PbxSn1-xTe. Gapless surface Dirac cones on bulk TCIs become gapped in thin films due to the finite-size effect, which is the hybridization between the states on the top and bottom surfaces. We clarify that the TCI film has a strong finite-size effect as compared to three-dimensional topological insulators such as Bi2Se3. Moreover, the energy gap oscillates with the thickness of film. The oscillation stems from topological phase transitions in two dimensions. The obtained data of the topological invariants and energy gap serve as guide to TCI-device applications.

Ozawa, Hideyuki; Yamakage, Ai; Sato, Masatoshi; Tanaka, Yukio

2014-07-01

122

Induced Compton-scattering effects in radiation-transport approximations  

SciTech Connect

The method of characteristics is used to solve radiation transport problems with induced Compton scattering effects included. The methods used to date have only addressed problems in which either induced Compton scattering is ignored, or problems in which linear scattering is ignored. Also, problems which include both induced Compton scattering and spatial effects have not been considered previously. The introduction of induced scattering into the radiation transport equation results in a quadratic nonlinearity. Methods are developed to solve problems in which both linear and nonlinear Compton scattering are important. Solutions to scattering problems are found for a variety of initial photon energy distributions.

Gibson, D.R. Jr.

1982-02-01

123

Radiation-induced charge trapping in bipolar base oxides  

SciTech Connect

Capacitance-voltage and thermally stimulated current methods are used to investigate radiation induced charge trapping in bipolar base oxides. Results are compared with models of oxide and interface trap charge buildup at low electric fields.

Fleetwood, D.M.; Riewe, L.C. [Sandia National Labs., Albuquerque, NM (United States); Witczak, Schrimpf, R.D. [Arizona Univ., Tucson, AZ (United States). Dept. of Electrical and Computer Engineering

1996-03-01

124

Clinical and dosimetric factors of radiation-induced esophageal injury: Radiation-induced esophageal toxicity  

PubMed Central

AIM: To analyze the clinical and dosimetric predictive factors for radiation-induced esophageal injury in patients with non-small-cell lung cancer (NSCLC) during three-dimensional conformal radiotherapy (3D-CRT). METHODS: We retrospectively analyzed 208 consecutive patients (146 men and 62 women) with NSCLC treated with 3D-CRT. The median age of the patients was 64 years (range 35-87 years). The clinical and treatment parameters including gender, age, performance status, sequential chemotherapy, concurrent chemotherapy, presence of carinal or subcarinal lymph nodes, pretreatment weight loss, mean dose to the entire esophagus, maximal point dose to the esophagus, and percentage of volume of esophagus receiving >55 Gy were studied. Clinical and dosimetric factors for radiation-induced acute and late grade 3-5 esophageal injury were analyzed according to Radiation Therapy Oncology Group (RTOG) criteria. RESULTS: Twenty-five (12%) of the two hundred and eight patients developed acute or late grade 3-5 esophageal injury. Among them, nine patients had both acute and late grade 3-5 esophageal injury, two died of late esophageal perforation. Concurrent chemotherapy and maximal point dose to the esophagus ?60 Gy were significantly associated with the risk of grade 3-5 esophageal injury. Fifty-four (26%) of the two hundred and eight patients received concurrent chemotherapy. Among them, 25 (46%) developed grade 3-5 esophageal injury (P = 0.0001<0.01). However, no grade 3-5 esophageal injury occurred in patients who received a maximal point dose to the esophagus <60 Gy (P = 0.0001<0.01). CONCLUSION: Concurrent chemotherapy and the maximal esophageal point dose ?60 Gy are significantly associated with the risk of grade 3-5 esophageal injury in patients with NSCLC treated with 3D-CRT. PMID:15849822

Qiao, Wen-Bo; Zhao, Yan-Hui; Zhao, Yan-Bin; Wang, Rui-Zhi

2005-01-01

125

Radiation-induced myeloid leukemia in murine models  

PubMed Central

The use of radiation therapy is a cornerstone of modern cancer treatment. The number of patients that undergo radiation as a part of their therapy regimen is only increasing every year, but this does not come without cost. As this number increases, so too does the incidence of secondary, radiation-induced neoplasias, creating a need for therapeutic agents targeted specifically towards incidence reduction and treatment of these cancers. Development and efficacy testing of these agents requires not only extensive in vitro testing but also a set of reliable animal models to accurately recreate the complex situations of radiation-induced carcinogenesis. As radiation-induced leukemic progression often involves genomic changes such as rearrangements, deletions, and changes in methylation, the laboratory mouse Mus musculus, with its fully sequenced genome, is a powerful tool in cancer research. This fact, combined with the molecular and physiological similarities it shares with man and its small size and high rate of breeding in captivity, makes it the most relevant model to use in radiation-induced leukemia research. In this work, we review relevant M. musculus inbred and F1 hybrid animal models, as well as methods of induction of radiation-induced myeloid leukemia. Associated molecular pathologies are also included. PMID:25062865

2014-01-01

126

Impurity induced crystallinity and optical emissions in ZnO nanorod arrays  

NASA Astrophysics Data System (ADS)

We report the growth of ZnO nanocrystallites doped with impurities such as B, N and S by green chemistry route using ultrasound. The effect of intrinsic defects and impurity doping on the structural and optical properties of ZnO nanostructures has been studied and discussed. Characterization studies carried out using x-ray diffraction (XRD) reveal the change in lattice parameters and crystallinity of ZnO in the presence of dopant. This has been explained on the basis of the dopant substitution at regular anion and interstitial sites. Study on surface morphology by field emission scanning electron microscopy (FESEM) shows a change from particle-like structure to aligned nanorods nucleated at definite sites. Elemental analysis such as x-ray photon electron spectroscopy (XPS) has been carried out to ascertain the dopant configuration in ZnO. This has been corroborated by the results obtained from FTIR and Raman studies. UV–vis light absorption and PL studies show an expansion of the band gap which has been explained on the basis of Moss–Burstein shift in the electronic band gap of ZnO by impurity incorporation. The optical emissions corresponding to excitonic transition and defect centres present in the band gap of ZnO is found to shift towards lower/higher wavelength sides. New PL bands observed have been assigned to the transitions related to the impurity states present in the band gap of ZnO along with intrinsic defects.

Panda, N. R.; Acharya, B. S.

2015-01-01

127

Strain-induced partially flat band, helical snake states and interface superconductivity in topological crystalline insulators  

NASA Astrophysics Data System (ADS)

Topological crystalline insulators in IV-VI compounds host novel topological surface states consisting of multi-valley massless Dirac fermions at low energy. Here we show that strain generically acts as an effective gauge field on these Dirac fermions and creates pseudo-Landau orbitals without breaking time-reversal symmetry. We predict the realization of this phenomenon in IV-VI semiconductor heterostructures, due to a naturally occurring misfit dislocation array at the interface that produces a periodically varying strain field. Remarkably, the zero-energy Landau orbitals form a flat band in the vicinity of the Dirac point, and coexist with a network of snake states at higher energy. We propose that the high density of states of this flat band gives rise to interface superconductivity observed in IV-VI semiconductor multilayers at unusually high temperatures, with non-Bardeen-Cooper-Schrieffer behaviour. Our work demonstrates a new route to altering macroscopic electronic properties to achieve a partially flat band, and provides a starting point for realizing novel correlated states of matter.

Tang, Evelyn; Fu, Liang

2014-12-01

128

Coherent microwave radiation from a laser induced plasma  

NASA Astrophysics Data System (ADS)

We propose a method for generation of coherent monochromatic microwave/terahertz radiation from a laser-induced plasma. It is shown that small-scale plasma, located in the interaction region of two co-propagating plane-polarized laser beams, can be a source of the dipole radiation at a frequency equal to the difference between the frequencies of the lasers. This radiation is coherent and appears as a result of the so-called optical mixing in plasma.

Shneider, M. N.; Miles, R. B.

2012-12-01

129

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

130

Protection from radiation-induced apoptosis by the radioprotector amifostine (WR-2721) is radiation dose dependent.  

PubMed

The radioprotective agent amifostine is a free radical scavenger that can protect cells from the damaging effects of ionising radiation when administered prior to radiation exposure. However, amifostine has also been shown to protect cells from chromosomal mutations when administered after radiation exposure. As apoptosis is a common mechanism by which cells with mutations are removed from the cell population, we investigated whether amifostine stimulates apoptosis when administered after radiation exposure. We chose to study a relatively low dose which is the maximum radiation dose for radiation emergency workers (0.25 Gy) and a high dose relevant to radiotherapy exposures (6 Gy). Mice were administered 400 mg/kg amifostine 30 min before, or 3 h after, whole-body irradiation with 0.25 or 6 Gy X-rays and apoptosis was analysed 3 or 7 h later in spleen and bone marrow. We observed a significant increase in radiation-induced apoptosis in the spleen of mice when amifostine was administered before or after 0.25 Gy X-rays. In contrast, when a high dose of radiation was used (6 Gy), amifostine caused a reduction in radiation-induced apoptosis 3 h post-irradiation in spleen and bone marrow similar to previously published studies. This is the first study to investigate the effect of amifostine on radiation-induced apoptosis at a relatively low radiation dose and the first to demonstrate that while amifostine can reduce apoptosis from high doses of radiation, it does not mediate the same effect in response to low-dose exposures. These results suggest that there may be a dose threshold at which amifostine protects from radiation-induced apoptosis and highlight the importance of examining a range of radiation doses and timepoints. PMID:24459009

Ormsby, Rebecca J; Lawrence, Mark D; Blyth, Benjamin J; Bexis, Katrina; Bezak, Eva; Murley, Jeffrey S; Grdina, David J; Sykes, Pamela J

2014-02-01

131

Epigenetic Regulation of ?A-crystallin in High Myopia-Induced Dark Nuclear Cataract  

PubMed Central

Purpose To assess the etiology of early-onset dark nucleus in high-myopic patients and its relationship with the epigenetic regulation of ?A-crystallin (CRYAA). Methods We reviewed clinical data from patients who underwent cataract surgery at our center in 2012. Lens epithelial samples were collected during capsulorhexis, whereas young lens epithelium was donated. Cataract type and severity were graded according to the Lens Opacity Classification System III (LOCS III). DNA methylation was analyzed by pyrosequencing the CpG islands of the CRYAA promoter in the following groups: Age-Related Cataract (ARC) Nuclear Color (NC) 2–3; High-Myopic Cataract (HMC) NC2–3; ARC NC5–6; HMC NC5–6; and in young lenses graded NC1. We analyzed CRYAA expression by real-time polymerase chain reaction (PCR), reverse transcription PCR, and immunohistochemistry. Results The odds ratio of dark nucleus in high-myopic patients was 5.16 (95% confidence interval: 3.98–6.69; p<0.001). CpG islands in lens epithelial CRYAA promoter in the HMC NC5–6 Group exhibited the highest methylation of all the groups, but no statistically significant differences were evident between the HMC NC2–3 and ARC NC2–3 Groups. Likewise, CRYAA mRNA and protein levels in the HMC NC5–6 Group were significantly lower than the ARC NC5–6 Group and high-myopic controls. Conclusions High myopia is a risk factor for dark nucleus. Downregulation of CRYAA via the hypermethylation of CpG islands in its promoter could underlie the earlier onset of dark nucleus in high-myopic patients. PMID:24312600

Zhang, Ke-Ke; Yang, Jin; Luo, Yi; Lu, Yi

2013-01-01

132

Halofuginone mediated protection against radiation-induced leg contracture.  

PubMed

Fibrosis of normal tissues often accompanies radiation treatment of cancer. Activation of the transforming growth factor-beta (TGF-beta) signaling pathway is thought to play a major role in radiation-induced fibrosis and has prompted the development and assessment of low molecular weight inhibitors of the pathway. Previous studies with halofuginone have shown it to inhibit TGF-beta signaling in vitro and protect mice from radiation-induced leg contraction (a model for soft tissue fibrosis). The current study confirms these findings for HaCaT cells stimulated with exogenous TGF-beta treatment. Reducing the halifuginone treatment from 7 days/week (used previously) to 5 days/week post-radiation exposure provided significant protection against radiation-induced leg contraction in mice 3 and 4 months post-radiation treatment. Halofuginone treatment was shown to attenuate TGF-beta signaling molecules taken from irradiated skin including TGF-betaRII, pSmad3, Smad7, and TSP1. The latter, TSP1, a co-activator of TGF-beta may serve as a suitable biomarker for monitoring the efficacy of halofuginone should it be evaluated in a clinical setting for protection against radiation-induced fibrosis. PMID:19578745

Ishii, Hisanari; Choudhuri, Rajani; Mathias, Askale; Sowers, Anastasia L; Flanders, Kathleen C; Cook, John A; Mitchell, James B

2009-08-01

133

Colostomy in radiation-induced rectal stricture  

Microsoft Academic Search

Summary and Conclusions  The subject of rectal stricture due to radiation therapy is reviewed and a case reported. Although the incidence of this condition\\u000a is low, it can occur in as many as 57 per cent of cases treated by radiation for carcinoma of the cervix. Pathology, symptoms\\u000a and treatment are discussed, and an illustrative case report is presented to show

Horace Chaitin

1971-01-01

134

The radiation-induced chemistry in solid xenon matrices  

NASA Astrophysics Data System (ADS)

The paper presents an overview of recent studies of the radiation-chemical transformations of guest molecules in solid xenon induced by fast electrons and x-ray irradiation. Specific features of the experimental approach based on the combination of matrix isolation IR and EPR spectroscopy are briefly outlined (with a particular emphasis on monoisotopic and isotopically enriched xenon matrices). The results reveal rich and diverse radiation-induced chemistry in solid xenon, which is considered in the following major aspects: (1) matrix-induced and matrix-assisted transformations of the primary guest radical cations; (2) production and dynamics of hydrogen atoms; (3) formation of xenon hydrides. Finally, preliminary results on the radiation-induced generation of oxygen atoms and ions in solid xenon are presented.

Feldman, V. I.; Kobzarenko, A. V.; Orlov, A. Y.; Sukhov, F. F.

2012-08-01

135

Electromagnetically Induced Transparency using six level atoms doped in the crystalline medium  

E-print Network

Using the density matrix theory of interaction between light and matter, and relevant parameters of the relaxation rates for a six-level model, we have shown theoretically the possibility of realizing Electromagnetically Induced Transparency (EIT) and Slow Light effects in Pr(+3 ion) doped YSO crystal. In addition, we have presented a simplified method to analyse EIT effect in such a six level atomic system. Finally, we have demonstrated results of numerical calculation and have compared them with experimental measurements reported recently.

Hassan Kaatuzian; Sina Mehrabadi; Ahmad Ajdarzadeh Oskouei

2005-11-21

136

Radiation-induced apoptosis in microvascular endothelial cells.  

PubMed

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. PMID:9043022

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

1997-01-01

137

Radio frequency radiation-induced hyperthermia using Si nanoparticle-based sensitizers for mild cancer therapy.  

PubMed

Offering mild, non-invasive and deep cancer therapy modality, radio frequency (RF) radiation-induced hyperthermia lacks for efficient biodegradable RF sensitizers to selectively target cancer cells and thus avoid side effects. Here, we assess crystalline silicon (Si) based nanomaterials as sensitizers for the RF-induced therapy. Using nanoparticles produced by mechanical grinding of porous silicon and ultraclean laser-ablative synthesis, we report efficient RF-induced heating of aqueous suspensions of the nanoparticles to temperatures above 45-50°C under relatively low nanoparticle concentrations (<1?mg/mL) and RF radiation intensities (1-5?W/cm(2)). For both types of nanoparticles the heating rate was linearly dependent on nanoparticle concentration, while laser-ablated nanoparticles demonstrated a remarkably higher heating rate than porous silicon-based ones for the whole range of the used concentrations from 0.01 to 0.4?mg/mL. The observed effect is explained by the Joule heating due to the generation of electrical currents at the nanoparticle/water interface. Profiting from the nanoparticle-based hyperthermia, we demonstrate an efficient treatment of Lewis lung carcinoma in vivo. Combined with the possibility of involvement of parallel imaging and treatment channels based on unique optical properties of Si-based nanomaterials, the proposed method promises a new landmark in the development of new modalities for mild cancer therapy. PMID:25391603

Tamarov, Konstantin P; Osminkina, Liubov A; Zinovyev, Sergey V; Maximova, Ksenia A; Kargina, Julia V; Gongalsky, Maxim B; Ryabchikov, Yury; Al-Kattan, Ahmed; Sviridov, Andrey P; Sentis, Marc; Ivanov, Andrey V; Nikiforov, Vladimir N; Kabashin, Andrei V; Timoshenko, Victor Yu

2014-01-01

138

Radio frequency radiation-induced hyperthermia using Si nanoparticle-based sensitizers for mild cancer therapy  

NASA Astrophysics Data System (ADS)

Offering mild, non-invasive and deep cancer therapy modality, radio frequency (RF) radiation-induced hyperthermia lacks for efficient biodegradable RF sensitizers to selectively target cancer cells and thus avoid side effects. Here, we assess crystalline silicon (Si) based nanomaterials as sensitizers for the RF-induced therapy. Using nanoparticles produced by mechanical grinding of porous silicon and ultraclean laser-ablative synthesis, we report efficient RF-induced heating of aqueous suspensions of the nanoparticles to temperatures above 45-50°C under relatively low nanoparticle concentrations (<1 mg/mL) and RF radiation intensities (1-5 W/cm2). For both types of nanoparticles the heating rate was linearly dependent on nanoparticle concentration, while laser-ablated nanoparticles demonstrated a remarkably higher heating rate than porous silicon-based ones for the whole range of the used concentrations from 0.01 to 0.4 mg/mL. The observed effect is explained by the Joule heating due to the generation of electrical currents at the nanoparticle/water interface. Profiting from the nanoparticle-based hyperthermia, we demonstrate an efficient treatment of Lewis lung carcinoma in vivo. Combined with the possibility of involvement of parallel imaging and treatment channels based on unique optical properties of Si-based nanomaterials, the proposed method promises a new landmark in the development of new modalities for mild cancer therapy.

Tamarov, Konstantin P.; Osminkina, Liubov A.; Zinovyev, Sergey V.; Maximova, Ksenia A.; Kargina, Julia V.; Gongalsky, Maxim B.; Ryabchikov, Yury; Al-Kattan, Ahmed; Sviridov, Andrey P.; Sentis, Marc; Ivanov, Andrey V.; Nikiforov, Vladimir N.; Kabashin, Andrei V.; Timoshenko, Victor Yu

2014-11-01

139

Light induced enhancement of minority carrier lifetime of chemically passivated crystalline silicon  

NASA Astrophysics Data System (ADS)

In this work we present light effects on chemically passivated silicon surface. Di-iodine-ethanol (I-E) mixtures were used to passivate silicon dangling bonds. The passivation quality is sensitive to both silicon surface state and light irradiation. The minority carrier lifetime values vary from 2 ?s for unpassivated surfaces to about 40 ?s for chemically passivated ones. FTIR investigations show that light irradiation catalyses the passivation effect by forming the silicon-ethoxylate group (sbnd Sisbnd Osbnd C2H5). We suggest a mechanism to explain the passivation effect based on carrier-induced dissociation of I2.

Aouida, S.; Bachtouli, N.; Bessais, B.

2013-06-01

140

Electromechanical actuation and current-induced metastable states in suspended single-crystalline VO2 nanoplatelets  

SciTech Connect

Current-induced electromechanical actuation enabled by the metal-insulator transition in VO{sub 2} nanoplatelets is demonstrated. The Joule heating by a sufficient current flowing through suspended nanoplatelets results in formation of heterophase domain patterns and is accompanied by nanoplatelet deformation. The actuation action can be achieved in a wide temperature range below the bulk phase transition temperature (68 C). The observed current-sustained heterophase domain structures should be interpreted as distinct metastable states in free-standing and end-clamped VO{sub 2} samples. We analyze the main prerequisites for the realization of a current-controlled actuator based on the proposed concept.

Tselev, Alexander [ORNL; Budai, John D [ORNL; Strelcov, Evgheni [Southern Illinois University; Tischler, Jonathan Zachary [ORNL; Kolmakov, Andrei [Southern Illinois University; Kalinin, Sergei V [ORNL

2011-01-01

141

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

142

?-Radiation Induced Color Centers in Anthracene  

Microsoft Academic Search

The effects of ?-irradiation on pure anthracene have been investigated by optical absorption and electron paramagnetic resonance (EPR) measurements. It is found that the optical absorption peaks which are produced by the radiation at 30°C are stable at 30°C but increase upon annealing up to 140°C; the most prominent of these being at 6060 Å and 5350 Å. EPR signals

Haywood Blum; P. L. Mattern; R. A. Arndt; A. C. Damask

1967-01-01

143

Hyperprolactinemia from radiation-induced hypothalamic hypopituitarism  

SciTech Connect

In 1975 Samaan et al., described the effects of radiation damage of the hypothalamus in 15 patients with head and neck cancer. Shalet et al., in 1977 described endocrine morbidity in adults who as children had been irradiated for brain tumors. This report describes instances of hyperprolactinemia and associated hypothalamic, pituitary, and thyroid dysfunction following irradiation of a young adult female for brain neoplasia.

Corkill, G.; Hanson, F.W.; Gold, E.M.; White, V.A.

1980-01-01

144

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. PMID:21829314

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

2010-01-01

145

Modulation of radiation-induced apoptosis by thiolamines.  

PubMed

Exposure to the thiolamine radioprotector N-(2-mercaptoethyl)-1,3-propanediamine (WR-1065) induced apoptosis in the mouse TB8.3 hybridoma after a 60-min (LD50 = 4.5 mM) or during a 20-h (LD50 = 0.15 mM) exposure. In contrast, a 20-h exposure to 17 mM L-cysteine or 10 mM cysteamine was required to induce 50% apoptosis within 20 h. Apoptosis was not induced by either a 60-min or 20-h exposure to 10 mM of the thiazolidine 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 (4 mM for 15 min) or cysteine (10 mM for 60 min) 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 h) did not. Treatment with either WR-1065, cysteine, RibCys or RibCyst for 60 min beginning 60 min after irradiation did not affect the level of radiation-induced apoptosis. In contrast, treatment with either cysteine, cysteamine or RibCys for 20 h beginning 60 min 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. PMID:9343109

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

1997-10-01

146

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

147

[Chlorophyll mutations induced by gamma radiation in Phaseolus vulgaris L].  

PubMed

In a study of chlorophyll mutants of Phaseolus vulgaris L. through Co60 gamma radiation, five types of mutants, classified as albino, cream, yellow, yellow-green and light green were obtained; all were lethal; their segregation was always proportionally lower than the Mendelian. Gamma radiation-induced mutations in black beans do not depart significantly from those obtained elsewhere in barley and wheat. PMID:1197814

Meoño, M E

1975-07-01

148

Pressure- and temperature-induced transformations in crystalline polymers of C60  

NASA Astrophysics Data System (ADS)

The great advantage of the C60 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 2 and sp 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 C60 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 C60 monomer.

Meletov, K. P.; Kourouklis, G. A.

2012-10-01

149

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

150

Effective surface passivation of p-type crystalline silicon with silicon oxides formed by light-induced anodisation  

NASA Astrophysics Data System (ADS)

Electronic surface passivation of p-type crystalline silicon by anodic silicon dioxide (SiO2) was investigated. The anodic SiO2 was grown by light-induced anodisation (LIA) in diluted sulphuric acid at room temperature, a process that is significantly less-expensive than thermal oxidation which is widely-used in silicon solar cell fabrication. After annealing in oxygen and then forming gas at 400 °C for 30 min, the effective minority carrier lifetime of 3-5 ? cm, boron-doped Czochralski silicon wafers with a phosphorus-doped 80 ?/? emitter and a LIA anodic SiO2 formed on the p-type surface was increased by two orders of magnitude to 150 ?s. Capacitance-voltage measurements demonstrated a very low positive charge density of 3.4 × 1011 cm-2 and a moderate density of interface states of 6 × 1011 eV-1 cm-2. This corresponded to a silicon surface recombination velocity of 62 cm s-1, which is comparable with values reported for other anodic SiO2 films, which required higher temperatures and longer growth times, and significantly lower than oxides grown by chemical vapour deposition techniques. Additionally, a very low leakage current density of 3.5 × 10-10 and 1.6 × 10-9 A cm-2 at 1 and -1 V, respectively, was measured for LIA SiO2 suggesting its potential application as insulation layer in IBC solar cells and a barrier for potential induced degradation.

Cui, Jie; Grant, Nicholas; Lennon, Alison

2014-12-01

151

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

152

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); Stulen, Richard H. (Livermore, CA)

2003-01-01

153

Radiation induced growth of micro crystallites  

NASA Astrophysics Data System (ADS)

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.

Meisel, D.

154

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

155

The Mechanisms of Radiation-Induced Bystander Effect  

PubMed Central

The radiation-induced bystander effect is the phenomenon which non-irradiated cells exhibit effects along with their different levels as a result of signals received from nearby irradiated cells. Responses of non-irradiated cells may include changes in process of translation, gene expression, cell proliferation, apoptosis and cells death. These changes are confirmed by results of some In-Vivo studies. Most well-known important factors affecting radiation-induced bystander effect include free radicals, immune system factors, expression changes of some genes involved in inflammation pathway and epigenetic factors. PMID:25599062

Najafi, M; Fardid, R; Hadadi, Gh; Fardid, M

2014-01-01

156

[Radiation-induced meningioma: the changing pattern of the disease].  

PubMed

In this country radiation-induced meningiomas were usually associated with low-dose irradiation of the scalp of immigrants from North Africa, given as part of the treatment of tinea capitis. An Ashkenazi patient developed meningiomas 15 years after high-dose irradiation for a benign lesion in the parasellar region. The accumulating literature about high-dose radiation-induced meningiomas is reviewed and attention is drawn to the ever increasing number of meningiomas observed in immigrants from the former Soviet Union. PMID:9153891

Sviri, G; Sahar, A; Feinsod, M

1997-02-16

157

Targeting CREB inhibits radiation-induced neuroendocrine differentiation and increases radiation-induced cell death in prostate cancer cells  

PubMed Central

Neuroendocrine differentiation (NED) is a process by which prostate cancer cells transdifferentiate into neuroendocrine-like (NE-like) cancer cells. Accumulated evidence suggests that NED is associated with disease progression and therapy resistance in prostate cancer patients. We previously reported that by mimicking a clinical radiotherapy protocol, fractionated ionizing radiation (FIR) induces NED in prostate cancer cells. Interestingly, FIR-induced NED constitutes two distinct phases: a radioresistance phase in which a fraction of cells selectively survive during the first two week irradiation, and a neuroendocrine differentiation phase in which surviving cells differentiate into NE-like cancer cells during the second two week irradiation. We have also observed increased activation of the transcription factor cAMP response element binding (CREB) protein during the course of FIR-induced NED. To determine whether targeting NED can be explored as a radiosensitization approach, we employed two CREB targeting strategies, CREB knockdown and overexpression of ACREB, a dominant-negative mutant of CREB, to target both phases. Our results showed that ACREB expression increased FIR-induced cell death and sensitized prostate cancer cells to radiation. Consistent with this, knockdown of CREB also inhibited FIR-induced NED and sensitized prostate cancer cells to radiation. Molecular analysis suggests that CREB targeting primarily increases radiation-induced pre-mitotic apoptosis. Taken together, our results suggest that targeting NED could be developed as a radiosensitization approach for prostate cancer radiotherapy. PMID:25520873

Suarez, Christopher D; Deng, Xuehong; Hu, Chang-Deng

2014-01-01

158

Peroxidase changes in barley induced by ionizing and thermal radiation.  

PubMed

Thermal and ionizing (gamma-ray) radiations were used to induce damage to barley seeds (IB65). The activity and isozyme banding patterns of peroxidase were compared. It was found that both physical agents caused damage to barley seeds (as observed from seedling height), but their action on peroxidase activity is not similar. Gamma-Rays enhance peroxidase activity. Thermal radiation, on the other hand, tends to reduce it but fails to alter the number of peroxidase isozymes. It is conjectured that the pathways of damage by thermal and ionizing radiations are not the same. PMID:8601749

Sah, N K; Pramanik, S; Raychaudhuri, S S

1996-01-01

159

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

160

Ion-Induced Radiation Damage in Biomolecular Systems  

NASA Astrophysics Data System (ADS)

The interaction of keV ions with building blocks of DNA and proteins is of fundamental interest to proton and heavy ion therapy. During the last decade, ion-induced ionization and fragmentation was studied for isolated biomolecules, biomolecular clusters, nanosolvated isolated biomolecules and solid thin biomolecular films. This article gives a brief overview over the research on biomolecular mechanisms underlying ion-induced radiation damage with a focus on the different target systems.

Schlathölter, Thomas

161

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

162

Si photoepitaxy induced by synchrotron radiation  

NASA Astrophysics Data System (ADS)

Epitaxial Si films are grown on Si substrates by synchrotron radiation-excited gas-source molecular beam epitaxy (MBE) using disilane. It is demonstrated that the epitaxial temperature is lowered to 40 degrees Celsius. Selective epitaxial growth between Si/SiO2 substrate can be achieved irrespective of growth time at temperatures above 700 degrees Celsius. For the B doping using disilane/decaborane, it is confirmed that SR irradiation significantly decreases the doping temperatue (80 degrees Celsius) and electrical activation rate.

Utsumi, Yuichi

1997-05-01

163

Radiation-induced endometriosis in Macaca mulatta  

SciTech Connect

Female rhesus monkeys received whole-body doses of ionizing radiation in the form of single-energy protons, mixed-energy protons, X rays, and electrons. Endometriosis developed in 53% of the monkeys during a 17-year period after exposure. Incidence rates for endometriosis related to radiation type were: single-energy protons, 54%; mixed-energy protons, 73%; X rays, 71%; and electrons, 57%. The incidence of endometriosis in nonirradiated control monkeys was 26%. Monkeys exposed to single-energy protons, mixed-energy protons, and X rays developed endometriosis at a significantly higher rate than control monkeys (chi 2, P less than 0.05). Severity of endometriosis was staged as massive, moderate, and minimal. The incidence of these stages were 65, 16, and 19%, respectively. Observations of clinical disease included weight loss in 43% of the monkeys, anorexia in 35%, space-occupying masses detected by abdominal palpation in 55%, abnormal ovarian/uterine anatomy on rectal examination in 89%, and radiographic evidence of abdominal masses in 38%. Pathological lesions were endometrial cyst formation in 69% of the monkeys, adhesions of the colon in 66%, urinary bladder in 50%, ovaries in 86%, and ureters in 44%, focal nodules of endometrial tissue throughout the omentum in 59%, and metastasis in 9%. Clinical management of endometriosis consisted of debulking surgery and bilateral salpingo-oophorectomy combined in some cases with total abdominal hysterectomy. Postoperative survival rates at 1 and 5 years for monkeys recovering from surgery were 48 and 36%, respectively.

Fanton, J.W.; Golden, J.G. (USAF School of Aerospace Medicine, Brooks AFB, TX (USA))

1991-05-01

164

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

165

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

166

Introduction Mammals suffering from radiation-induced anemia or  

E-print Network

Introduction Mammals suffering from radiation-induced anemia or neutropenia can be rescued by stromal-derived factor-1 (SDF-1) neutralization or CXCR4-blocking antibody, but could be reduced by addition of c-met-blocking antibody and augmented by hepatocyte growth factor (HGF), the putative ligand

Zandstra, Peter W.

167

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

168

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...

169

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

170

Kinetics of radiation-induced segregation in ternary alloys. [LMFBR  

SciTech Connect

Model calculations of radiation-induced segregation in ternary alloys have been performed, using a simple theory. The theoretical model describes the coupling between the fluxes of radiation-induced defects and alloying elements in an alloy A-B-C by partitioning the defect fluxes into those occurring via A-, B-, and C-atoms, and the atom fluxes into those taking place via vacancies and interstitials. The defect and atom fluxes can be expressed in terms of concentrations and concentration gradients of all the species present. With reasonable simplifications, the radiation-induced segregation problem can be cast into a system of four coupled partial-differential equations, which can be solved numerically for appropriate initial and boundary conditions. Model calculations have been performed for ternary solid solutions intended to be representative of Fe-Cr-Ni and Ni-Al-Si alloys under various irradiation conditions. The dependence of segregation on both the alloy properties and the irradiation variables, e.g., temperature and displacement rate, was calculated. The sample calculations are in good qualitative agreement with the general trends of radiation-induced segregation observed experimentally.

Lam, N.Q.; Kumar, A.; Wiedersich, H.

1982-01-01

171

Gamma Radiation Induced Calibration Shift for Four Cryogenic Thermometer Types  

NASA Astrophysics Data System (ADS)

Cryogenic temperature sensors utilized in space environments are exposed to ionizing radiation with the total dose dependent upon the length of the mission. Based upon their minimal size and robust packaging, four models of cryogenic Resistance Thermometer Devices (RTDs) manufactured by Lake Shore Cryotronics, Inc. were tested to determine their reliability for space applications with regard to radiation. Samples of Cernox™ RTDs (CX-1050-SD), ruthenium oxide RTDs (models RX-102A-AA and RX-103A-AA), and silicon diode thermometers (model DT-670-SD) were irradiated at room temperature by a cesium-137 gamma source to total doses ranging from 5 Gy to 10 kGy. This paper presents the resulting temperature shifts induced by the gamma radiation as a function of total dose over the 1.4 K to 325 K temperature range. These data show that 1) Cernox™ RTDs exhibit high radiation hardness to 10 kGy from 1.4 K to 325 K, 2) ruthenium oxide RTDs show moderate radiation hardness to 10 kGy below 10 K, and 3) silicon diodes temperature sensors exhibit some radiation tolerance to low levels of radiation (especially below 70 K), but quickly shift calibration at radiation levels above 300 Gy, especially above 100 K.

Courts, S. Scott; Yeager, C. J.

2004-06-01

172

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

173

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

174

Radiation-Induced Bystander Response: Mechanism and Clinical Implications.  

PubMed

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. PMID:24761341

Suzuki, Keiji; Yamashita, Shunichi

2014-01-01

175

Radiation-induced dural fibrosarcoma with unusually short latent period  

SciTech Connect

Although rare, the occurrence of radiation-induced intracranial neoplasms of various types is well known. Among these tumors, fibrosarcomas, especially in the region of seila turcica, seem to be the most common type. These tumors characteristically occur after a long latent period, usually several years, following radiation therapy. The authors now report a case of apparently radiation-induced fibrosarcoma with some unusual features in a 10-year-old boy who was treated with radiation for medulloblastoma. He received a total dose of 53.2 Gy radiation delivered at 1.8 per fraction with 6 MV acceleration using the standard craniospinal technique. An MRI at 15 months after the completion of radiotherapy showed a mass over the cerebral convexity, which increased two-fold in size within a period of 4 months. A well circumscribed tumor was removed from the fronto-parietal convexity. The tumor measured 5x4.5x1.5 cm and was attached to the dura with invasion of the overlying bone. Histologically, it displayed the characteristic features of a low-grade fibrosarcoma. The patient remains free of tumor 18 months after the surgery. This case emphasizes the potential risk for the development of a second neoplasm following therapeutic radiation and also documents, to the authors' knowledge, the shortest latent period reported so far between administration of radiotherapy and development of an intracranial tumor.

Ghatak, N.R.; Aydin, F.; Leshner, R.T. (Medical College of Virginia, Richmond (United States) Tulane Univ., New Orleans, LA (United States))

1993-05-01

176

Countermeasures for space radiation induced adverse biologic effects  

NASA Astrophysics Data System (ADS)

Radiation exposure in space is expected to increase the risk of cancer and other adverse biological effects in astronauts. The types of space radiation of particular concern for astronaut health are protons and heavy ions known as high atomic number and high energy (HZE) particles. Recent studies have indicated that carcinogenesis induced by protons and HZE particles may be modifiable. We have been evaluating the effects of proton and HZE particle radiation in cultured human cells and animals for nearly a decade. Our results indicate that exposure to proton and HZE particle radiation increases oxidative stress, cytotoxicity, cataract development and malignant transformation in in vivo and/or in vitro experimental systems. We have also shown that these adverse biological effects can be prevented, at least partially, by treatment with antioxidants and some dietary supplements that are readily available and have favorable safety profiles. Some of the antioxidants and dietary supplements are effective in preventing radiation induced malignant transformation in vitro even when applied several days after the radiation exposure. Our recent progress is reviewed and discussed in the context of the relevant literature.

Kennedy, A. R.; Wan, X. S.

2011-11-01

177

Dynamics of plasma formation, relaxation, and topography modification induced by femtosecond laser pulses in crystalline and amorphous dielectrics  

SciTech Connect

We have studied plasma formation and relaxation dynamics along with the corresponding topography modifications in fused silica and sapphire induced by single femtosecond laser pulses (800 nm and 120 fs). These materials, representative of high bandgap amorphous and crystalline dielectrics, respectively, require nonlinear mechanisms to absorb the laser light. The study employed a femtosecond time-resolved microscopy technique that allows obtaining reflectivity and transmission images of the material surface at well-defined temporal delays after the arrival of the pump pulse which excites the dielectric material. The transient evolution of the free-electron plasma formed can be followed by combining the time-resolved optical data with a Drude model to estimate transient electron densities and skin depths. The temporal evolution of the optical properties is very similar in both materials within the first few hundred picoseconds, including the formation of a high reflectivity ring at about 7 ps. In contrast, at longer delays (100 ps-20 ns) the behavior of both materials differs significantly, revealing a longer lasting ablation process in sapphire. Moreover, transient images of sapphire show a concentric ring pattern surrounding the ablation crater, which is not observed in fused silica. We attribute this phenomenon to optical diffraction at a transient elevation of the ejected molten material at the crater border. On the other hand, the final topography of the ablation crater is radically different for each material. While in fused silica a relatively smooth crater with two distinct regimes is observed, sapphire shows much steeper crater walls, surrounded by a weak depression along with cracks in the material surface. These differences are explained in terms of the most relevant thermal and mechanical properties of the material. Despite these differences the maximum crater depth is comparable in both material at the highest fluences used (16 J/cm{sup 2}). The evolution of the crater depth as a function of fluence can be described taking into account the individual bandgap of each material.

Puerto, D.; Siegel, J.; Gawelda, W.; Galvan-Sosa, M.; Solis, J. [Laser Processing Group, Instituto de Optica-CSIC, Madrid (Spain); Ehrentraut, L. [Max-Born-Institut fuer Nichtlineare Optik und Kurzzeitspektroskopie, Berlin (Germany); Bonse, J. [Bundesanstalt fuer Materialforschung und-pruefung (BAM), Berlin (Germany)

2010-05-15

178

Pivotal role of augmented ?B-crystallin in tumor development induced by deficient TSC1/2 complex.  

PubMed

Tuberous sclerosis complex 1 (TSC1) and TSC2 are suppressors of mechanistic target of rapamycin (mTOR). mTOR is the major component of two protein complexes: mTOR complex 1 (mTORC1) and mTORC2. Inactive mutation of either TSC1 or TSC2 unleashes mTOR signaling and consequently causes TSC, a benign tumor syndrome affecting multiple organs. We report here that expression of ?B-crystallin was upregulated in Tsc1-/- or Tsc2-/- mouse embryonic fibroblasts, Eker rat uterine leiomyoma-derived Tsc2-deficient ELT3 cells, mutant Tsc2-associated mouse kidney tumors, and human lung lymphangioleiomyomatosis nodules. ?B-crystallin was transcriptionally activated by mTOR complex 2 (mTORC2): nuclear factor-kappa B (NF?B) signaling cascade. The augmented ?B-crystallin was critical for the migration, invasion and apoptotic resistance of Tsc2-defective cells. Disruption of ?B-crystallin suppressed Tsc2-null cell proliferation and tumorigenesis. Therefore, enhanced ?B-crystallin has an essential role in TSC1/2 complex deficiency-mediated tumorigenesis, and inhibition of ?B-crystallin may complement the current therapy for TSC. PMID:24077282

Wang, F; Chen, X; Li, C; Sun, Q; Chen, Y; Wang, Y; Peng, H; Liu, Z; Chen, R; Liu, K; Yan, H; Ye, B H; Kwiatkowski, D J; Zhang, H

2014-08-21

179

Radiation induced viscous flow in amorphous thin films  

NASA Astrophysics Data System (ADS)

We investigate surface roughness and stress relaxation in amorphous thin films during ion beam irradiation by a combination of experiments and molecular dynamics simulations. These experiments show, that smoothing occurs by a viscous mechanism. With computer simulations we investigate the model system CuTi, and find that radiation induced viscous flow is independent of the recoil energy between 100 and 15keV, when compared on the basis of defect production. Additionally we can identify a threshold recoil energy for flow of approximately 10eV. We show, that point defects can mediate the flow, by injection of interstitial and vacancy-like defects, which induce the same amount of flow as recoil events. The results are compared with the thermal spike model of radiation induced viscous flow.

Mayr, S. G.; Ashkenazy, Y.; Averback, R. S.

2003-03-01

180

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

181

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

182

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

183

Ionizing radiation-induced mutagenesis: radiation studies in Neurospora predictive for results in mammalian cells  

NASA Technical Reports Server (NTRS)

Ionizing radiation was the first mutagen discovered and was used to develop the first mutagenicity assay. In the ensuing 70+ years, ionizing radiation became a fundamental tool in understanding mutagenesis and is still a subject of intensive research. Frederick de Serres et al. developed and used the Neurospora crassa ad-3 system initially to explore the mutagenic effects of ionizing radiation. Using this system, de Serres et al. demonstrated the dependence of the frequency and spectra of mutations induced by ionizing radiation on the dose, dose rate, radiation quality, repair capabilities of the cells, and the target gene employed. This work in Neurospora predicted the subsequent observations of the mutagenic effects of ionizing radiation in mammalian cells. Modeled originally on the mouse specific-locus system developed by William L. Russell, the N. crassa ad-3 system developed by de Serres has itself served as a model for interpreting the results in subsequent systems in mammalian cells. This review describes the primary findings on the nature of ionizing radiation-induced mutagenesis in the N. crassa ad-3 system and the parallel observations made years later in mammalian cells.

Evans, H. H.; DeMarini, D. M.

1999-01-01

184

[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

185

Radiation-Induced Notch Signaling in Breast Cancer Stem Cells  

SciTech Connect

Purpose: To explore patterns of Notch receptor and ligand expression in response to radiation that could be crucial in defining optimal dosing schemes for ?-secretase inhibitors if combined with radiation. Methods and Materials: Using MCF-7 and T47D breast cancer cell lines, we used real-time reverse transcription–polymerase chain reaction to study the Notch pathway in response to radiation. Results: We show that Notch receptor and ligand expression during the first 48 hours after irradiation followed a complex radiation dose–dependent pattern and was most pronounced in mammospheres, enriched for breast cancer stem cells. Additionally, radiation activated the Notch pathway. Treatment with a ?-secretase inhibitor prevented radiation-induced Notch family gene expression and led to a significant reduction in the size of the breast cancer stem cell pool. Conclusions: Our results indicate that, if combined with radiation, ?-secretase inhibitors may prevent up-regulation of Notch receptor and ligand family members and thus reduce the number of surviving breast cancer stem cells.

Lagadec, Chann [Department of Radiation Oncology, David Geffen School of Medicine at University of California, Los Angeles (UCLA), Los Angeles, California (United States); Vlashi, Erina [Department of Radiation Oncology, David Geffen School of Medicine at University of California, Los Angeles (UCLA), Los Angeles, California (United States); Jonsson Comprehensive Cancer Center at UCLA, Los Angeles, California (United States); Alhiyari, Yazeed; Phillips, Tiffany M.; Bochkur Dratver, Milana [Department of Radiation Oncology, David Geffen School of Medicine at University of California, Los Angeles (UCLA), Los Angeles, California (United States); Pajonk, Frank, E-mail: fpajonk@mednet.ucla.edu [Department of Radiation Oncology, David Geffen School of Medicine at University of California, Los Angeles (UCLA), Los Angeles, California (United States); Jonsson Comprehensive Cancer Center at UCLA, Los Angeles, California (United States)

2013-11-01

186

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

187

Modeling radiation-induced mixing at interfaces between low solubility metals  

E-print Network

This thesis studies radiation-induced mixing at interfaces between low solubility metals using molecular dynamics (MD) computer simulations. It provides original contributions on the fundamental mechanisms of radiation-induced ...

Zhang, Liang, Ph. D. Massachusetts Institute of Technology

2014-01-01

188

Titanium carbide nanocube core induced interfacial growth of crystalline polypyrrole/polyvinyl alcohol lamellar shell for wide-temperature range supercapacitors  

NASA Astrophysics Data System (ADS)

This is the first investigation on electrically conducting polymers-based supercapacitor electrodes over a wide temperature range, from -18 °C to 60 °C. A high-performance supercapacitor electrode material consisting of TiC nanocube core and conformal crystalline polypyrrole (PPy)/poly-vinyl-alcohol (PVA) lamellar shell has been synthesized by heterogeneous nucleation-induced interfacial crystallization. PPy is induced to crystallize on the negatively charged TiC nanocube surfaces via strong interfacial interactions. In this organic-inorganic hybrid nanocomposite, the long chain PVA enables enhanced cycle life due to improved mechanical properties, and the TiC nanocube not only contributes to electron conduction, but also dictates the PPy morphology/crystallinity for maximizing the charging-discharging performance. The crystalline PPy/PAV layer on the TiC nanocube offers unprecedented high capacity (>350 F g-1-PPy at 300 mV s-1 with ?V = 1.6 V) and cycling stability in a temperature range from -18 °C to 60 °C. The presented hybrid-filler and interfacial crystallization strategies can be applied to the exploration of new-generation high-power conducting polymer-based supercapacitor materials.

Weng, Yu-Ting; Pan, Hsiao-An; Wu, Nae-Lih; Chen, Geroge Zheng

2015-01-01

189

Radiation-induced multi-organ involvement and failure: challenges for radiation accident medical management and future research  

Microsoft Academic Search

A common feature of radiation accidents is the medical consequences of dose-dependent radiation- induced multi-organ involvement (RIMOI) and radiation-induced multi-organ failure (RIMOF). Both RIMOI and RIMOF contribute to the clinical outcome and prognosis of radiation accident victims. A most remarkable fact in this context is that the specific pathophysiological mechanisms involved in RIMOI and RIMOF as a function of time

V Meineke; T M FLIEDNER

2005-01-01

190

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

191

Quantification of anti-aggregation activity of UV-irradiated ?-crystallin.  

PubMed

Ultraviolet radiation is a risk factor for cataractogenesis. It is believed that enhanced rates of lens opacification and cataract formation are the results of gradual loss of chaperone-like efficiency of ?-crystallin upon exposure to UV light. To characterize chaperone-like activity of ?-crystallin damaged by UV irradiation, a test system based on dithiothreitol-induced aggregation of holo-?-lactalbumin from bovine milk was used. The adsorption capacity of ?-crystallin (AC0) with respect to the target protein (?-lactalbumin) was used as a measure of anti-aggregation activity of ?-crystallin. The data on SDS-PAGE testify that UV irradiation of ?-crystallin results in covalent cross-linking of subunits in ?-crystallin oligomers. The dependence of AC0 value on the irradiation dose was compared with the UV-induced diminution of the portion of native ?-crystallin estimated from the data on differential scanning calorimetry. On the basis of such comparison a conclusion has been made that the loss in chaperone-like activity is mainly due to UV-induced denaturation of ?-crystallin subunits. Cross-linking of remaining native subunits leads to an additional decrease in anti-aggregation activity. PMID:25445690

Borzova, Vera A; Markossian, Kira A; Muranov, Konstantin O; Polyansky, Nikolay B; Kleymenov, Sergey Yu; Kurganov, Boris I

2015-02-01

192

Radiation-induced cardiomyopathy as a function of radiation beam gating to the cardiac cycle  

NASA Astrophysics Data System (ADS)

Portions of the heart are often unavoidably included in the primary treatment volume during thoracic radiotherapy, and radiation-induced heart disease has been observed as a treatment-related complication. Such complications have been observed in humans following radiation therapy for Hodgkin's disease and treatment of the left breast for carcinoma. Recent attempts have been made to prevent re-stenosis following angioplasty procedures using external beam irradiation. These attempts were not successful, however, due to the large volume of heart included in the treatment field and subsequent cardiac morbidity. We suggest a mechanism for sparing the heart from radiation damage by synchronizing the radiation beam with the cardiac cycle and delivering radiation only when the heart is in a relatively hypoxic state. We present data from a rat model testing this hypothesis and show that radiation damage to the heart can be altered by synchronizing the radiation beam with the cardiac cycle. This technique may be useful in reducing radiation damage to the heart secondary to treatment for diseases such as Hodgkin's disease and breast cancer.

Gladstone, David J.; Flanagan, Michael F.; Southworth, Jean B.; Hadley, Vaughn; Thibualt, Melissa Wei; Hug, Eugen B.; Hoopes, P. Jack

2004-04-01

193

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

194

Oxidative Stress Mediates Radiation Lung Injury by Inducing Apoptosis  

SciTech Connect

Purpose: Apoptosis in irradiated normal lung tissue has been observed several weeks after radiation. However, the signaling pathway propagating cell death after radiation remains unknown. Methods and Materials: C57BL/6J mice were irradiated with 15 Gy to the whole thorax. Pro-apoptotic signaling was evaluated 6 weeks after radiation with or without administration of AEOL10150, a potent catalytic scavenger of reactive oxygen and nitrogen species. Results: Apoptosis was observed primarily in type I and type II pneumocytes and endothelium. Apoptosis correlated with increased PTEN expression, inhibition of downstream PI3K/AKT signaling, and increased p53 and Bax protein levels. Transforming growth factor-{beta}1, Nox4, and oxidative stress were also increased 6 weeks after radiation. Therapeutic administration of AEOL10150 suppressed pro-apoptotic signaling and dramatically reduced the number of apoptotic cells. Conclusion: Increased PTEN signaling after radiation results in apoptosis of lung parenchymal cells. We hypothesize that upregulation of PTEN is influenced by Nox4-derived oxidative stress. To our knowledge, this is the first study to highlight the role of PTEN in radiation-induced pulmonary toxicity.

Zhang Yu; Zhang Xiuwu; Rabbani, Zahid N. [Department of Radiation Oncology, Duke University Medical Center, Durham, NC (United States); Jackson, Isabel L. [Department of Pathology, Duke University Medical Center, Durham, NC (United States); Vujaskovic, Zeljko, E-mail: vujas@radonc.duke.edu [Department of Radiation Oncology, Duke University Medical Center, Durham, NC (United States); Department of Pathology, Duke University Medical Center, Durham, NC (United States)

2012-06-01

195

Liquid-crystalline self-organization of isocyanide-containing dendrimers induced by coordination to gold(I) fragments.  

PubMed

Dendritic polyisocyanides can be considered as promising polytopic ligands to generate a great diversity of metallodendrimers due to the ability of the isocyanide moiety to bind to various transition metals. Here, new isocyanide-containing dendrimers and their corresponding polynuclear gold complexes have been prepared, [G(i)(NC)(Z)] and [G(i)(NCAuR)(Z)], respectively, where G(i) is a poly(phenyl ether) dendrimer, i is the generation number (i = 0, 1, or 2), Z is the number of peripheral groups (Z = 3 x 2(i)), and AuR are the surface groups ([R = Cl, C[triple bond]C-C(6)H(4)-OC(12)H(25), C[triple bond]CC(6)H(2)(OC(12)H(25))(3)]. The compounds are derived from a highly flexible phenyl ether-based dendritic core, G(i), having the general formula G(0) = C(6)H(3)(OC(11)H(22)OC(6)H(4)-)(3), G(1) = C(6)H(3)[OC(11)H(22)OC(6)H(3)(OC(11)H(22)OC(6)H(4)-)(2)](3), G(2) = C(6)H(3)[OC(11)H(22)OC(6)H(3){OC(11)H(22)OC(6)H(3)(OC(11)H(22)OC(6)H(4)-)(2)}(2)](3)), growing from the trivalent phloroglucinol and with undecylene aliphatic spacers between each branching benzene ring and end-functionalized by isocyanide groups. As in their monomeric model counterparts, stable liquid-crystalline phases are induced upon complexation of the AuR gold moieties at the branch termini. The nature of the anionic ligand R promotes the appearance of smectic or columnar mesophases, the formation of which are governed by steric and dipolar interactions. Based on X-ray diffraction experiments, models describing the supramolecular organization of these metallodendrimers into smectic and columnar mesophases are proposed: columnar phases result from the one-dimensional stacking of molecular disks made of self-assembled supermolecules in oblate cylindrical conformation, while the smectic phases form by the lateral two-dimensional registry of the supermolecules in antiparallel head-to-head prolate conformation. PMID:20055502

Cordovilla, Carlos; Coco, Silverio; Espinet, Pablo; Donnio, Bertrand

2010-02-01

196

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

197

Caffeine Markedly Enhanced Radiation-Induced Bystander Effects  

NASA Astrophysics Data System (ADS)

In this paper it is shown that incubation with 2 mM caffeine enhanced significantly the MN (micronucleus) formation in both the 1 cGy ?-particle irradiated and non-irradiated bystander regions. Moreover, caffeine treatment made the non-irradiated bystander cells more sensitive to damage signals. Treated by c-PTIO(2-(4-carboxy-phenyl)-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide), a nitric oxide (NO) scavenger, the MN frequencies were effectively inhibited, showing that nitric oxide might be very important in mediating the enhanced damage. These results indicated that caffeine enhanced the low dose ?-particle radiation-induced damage in irradiated and non-irradiated bystander regions, and therefore it is important to investigate the relationship between the radiosensitizer and radiation-induced bystander effects (RIBE).

Jiang, Erkang; Wu, Lijun

2009-04-01

198

Image reconstruction with acoustic radiation force induced shear waves  

NASA Astrophysics Data System (ADS)

Acoustic radiation force may be used to induce localized displacements within tissue. This phenomenon is used in Acoustic Radiation Force Impulse Imaging (ARFI), where short bursts of ultrasound deliver an impulsive force to a small region. The application of this transient force launches shear waves which propagate normally to the ultrasound beam axis. Measurements of the displacements induced by the propagating shear wave allow reconstruction of the local shear modulus, by wave tracking and inversion techniques. Here we present in vitro, ex vivo and in vivo measurements and images of shear modulus. Data were obtained with a single transducer, a conventional ultrasound scanner and specialized pulse sequences. Young's modulus values of 4 kPa, 13 kPa and 14 kPa were observed for fat, breast fibroadenoma, and skin. Shear modulus anisotropy in beef muscle was observed.

McAleavey, Stephen A.; Nightingale, Kathryn R.; Stutz, Deborah L.; Hsu, Stephen J.; Trahey, Gregg E.

2003-05-01

199

Inner-shell electron excitation effect on the structural change in amorphous and crystalline GaAs with brilliant X-ray irradiation using synchrotron radiation  

SciTech Connect

Amorphous layers of gallium arsenide (a-GaAs) formed by heavy implantation of silicon ions and crystalline gallium arsenide (c-GaAs) were irradiated with monochromatized X-rays using brilliant synchrotron radiation. Infrared absorption measurements at low temperature for a-GaAs specimens showed that X-rays having an energy larger than the K-binding energy of As atoms created a much larger fraction of Si-Ga and Si-As bondings than in the as-implanted state. On the other hand, from photoluminescence measurements, it was confirmed that X-rays having a smaller energy than either of the K binding energies, enhanced the relaxation of the a-GaAs network, and created some defects in c-Ga-As. The mechanism for these structural changes is discussed from the viewpoint of relaxation processes after inner-shell electron excitation by X-rays.

Sato, Fumio; Saito, Nobuo; Kusano, Junichi; Takizawa, Kuniharu [NHK Science and Technical Research Labs., Kinuta, Tokyo (Japan); Kawado, Seiji [Sony Corp. Research Center, Yokohama (Japan); Kato, Takanori [Sumitomo Heavy Industries, Ltd., Tanashi, Tokyo (Japan); Sugiyama, Hiroshi; Kagoshima, Yasushi; Ando, Masami [National Lab. for High Energy Physics, Tsukuba, Ibaraki (Japan)

1998-09-01

200

Cosmic ray radiation effects caused by proton-induced fragmentation.  

PubMed

In space, radiation effects in which a large amount of energy is transferred by a single particle are observed. These effects can be caused by either the direct ionization of a cosmic ray heavy ion or alternatively by the ionization of short range target fragments which are produced inside the material by interactions of cosmic ray particles. Protons of the lower radiation belt contribute significantly to target fragmentation; especially in the South Atlantic Anomaly (SAA). To allow predictions of possible radiation hazards the characteristics of these interactions at energies below 100 MeV must be understood in detail. We have performed an experiment to measure the proton induced fragmentation cross sections for carbon target nuclei at about 70 MeV/nucleon and to determine some characteristics of the kinematics of the target fragments. For this purpose experimental setups with CR-39 track detectors were used. In this paper we describe the experimental technique and present some preliminary results. PMID:11541798

Heinrich, W; Streibel, T; Ahrendt, M; Rocher, H; Huntrup, G

1997-01-01

201

Radiation Induced Charge Trapping in Ultrathin Based MOSFETs  

Microsoft Academic Search

Radiation induced charge trapping in ultrathin HfO2 -based n-channel MOSFETs is characterized as a function of dielectric thickness and irradiation bias following exposure to 10 keV X-rays and\\/or constant voltage stress. Positive and negative oxide-trap charges are observed, depending on irradiation and bias stress conditions. No significant interface-trap buildup is found in these devices under these irradiation and stress conditions.

Sriram K. Dixit; Xing J. Zhou; Ronald D. Schrimpf; Daniel M. Fleetwood; Sokrates T. Pantelides; Rino Choi; Gennadi Bersuker; Leonard C. Feldman

2007-01-01

202

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

203

Radiation damage of gallium arsenide induced by reactive ion etching  

Microsoft Academic Search

Radiation damage induced in the surface of gallium arsenide (GaAs) by reactive ion etching (RIE)is studied using physical and electrical analyses. The number of displaced Ga and As atoms observed by Rutherford backscattering spectrometry aligned spectra is 7.8×1015 cm?2 and 1.3×1016 cm?2 at rf power of 300 W (0.47 W\\/cm2) and 500 W (0.78 W\\/cm2), respectively. The barrier height of

Tohru Hara; Hidenori Suzuki; Akio Suga; Toshiyuki Terada; Nobuyuki Toyoda

1987-01-01

204

Radiative and phonon-induced dephasing in double quantum dots  

E-print Network

Abstract. A simple method for describing the evolution of a quantum state of a double quantum dot system interacting simultaneously with the electromagnetic environment and with the lattice modes is developed. It is shown that the joint action of the two reservoirs leads to nontrivial effects in the system dephasing. As an example, the impact of phonon-induced initial dephasing on the radiative decay of delocalized exciton states is discussed. 1.

unknown authors

205

Radiation-induced defect centers in glass ceramics  

Microsoft Academic Search

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 +\\/

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

1989-01-01

206

Radiation-induced defect centers in glass ceramics  

Microsoft Academic Search

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+ center, several types of oxygen hole centers (OHCs), an aluminum-oxygen hole center (Al-OHC), an Fe3+ center, Ti3+ and Zr3+ centers, and three

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

1989-01-01

207

Repair of radiation-induced genetic damage under microgravity  

Microsoft Academic Search

The influence of microgravity on the repair of radiation induced genetic damage in a temperature-conditional repair mutant of the yeast Saccharomyces cerevisiae (rad 54-3) was investigated onboard the IML-1 mission (January 22th - 30th 1992, STS-42). Cells were irradiated before the flight, incubated under microgravity at the permissive (22°C) and restrictive (36°C) temperature and afterwards tested for survival. The results

H.-D. Pross; M. Kost; J. Kiefer

1994-01-01

208

Ionizing Radiation Induces Human Intercellular Adhesion Molecule1 In Vitro  

Microsoft Academic Search

Intercellular adhesion molecule-1 (ICAM-1) plays a central role in various inflammatory reactions and its expression is readily induced by inflammatory stimuli such as cytokines or ultraviolet irradiation. We have investigated the effect of ionizing radiation (IR) on human ICAM-1 expression in human cell lines and skin cultures. ICAM-1 mRNA levels in HL60, HaCaT, and HeLa cells were elevated at 3-6

Uta Behrends; Ralf U. Peter; Renate Hintermeier-Knabe; Günther Eißner; Ernst Holler; Georg W. Bornkamm; S. Wright Caughman; Klaus Degitz

1994-01-01

209

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

210

Giant langerhans cells induced by psoralen and ultraviolet radiation  

Microsoft Academic Search

Treatment of psoriasis with psoralens and long-wave ultraviolet radiation (320-440 nm, UVA) is an effective treatment. The risk that it might induce cutaneous carcinoma has recently been discussed [6, 7]. In Uppsala we have used photochemotherapy with trioxsalen baths (0.05 % trioxsalen dissolved in 100 ml ethylalcohol added to 1501 of water at 37~ for 15 min followed by irradiation

Lennart Juhlin; Walter B. Shelley

1979-01-01

211

Heat Induced Damage Detection by Terahertz (THz) Radiation  

Microsoft Academic Search

Terahertz (THz) and sub-terahertz imaging and spectroscopy are becoming increasingly popular nondestructive evaluation techniques\\u000a for damage detection and characterization of materials. THz radiation is being used for inspecting ceramic foam tiles used\\u000a in TPS (Thermal Protection System), thick polymer composites and polymer tiles that are not good conductors of ultrasonic\\u000a waves. Capability of THz electromagnetic waves in detecting heat induced

Ehsan Kabiri Rahani; Tribikram Kundu; Ziran Wu; Hao Xin

2011-01-01

212

Crosstalk between telomere maintenance and radiation effects: A key player in the process of radiation-induced carcinogenesis.  

PubMed

It is well established that ionizing radiation induces chromosomal damage, both following direct radiation exposure and via non-targeted (bystander) effects, activating DNA damage repair pathways, of which the proteins are closely linked to telomeric proteins and telomere maintenance. Long-term propagation of this radiation-induced chromosomal damage during cell proliferation results in chromosomal instability. Many studies have shown the link between radiation exposure and radiation-induced changes in oxidative stress and DNA damage repair in both targeted and non-targeted cells. However, the effect of these factors on telomeres, long established as guardians of the genome, still remains to be clarified. In this review, we will focus on what is known about how telomeres are affected by exposure to low- and high-LET ionizing radiation and during proliferation, and will discuss how telomeres may be a key player in the process of radiation-induced carcinogenesis. PMID:24486376

Shim, Grace; Ricoul, Michelle; Hempel, William M; Azzam, Edouard I; Sabatier, Laure

2014-01-31

213

On the time-dependency of the flow-induced dynamic moduli of a liquid crystalline hydroxypropylcellulose solution  

Microsoft Academic Search

Some unusual rheological features of a liquid crystalline solution of hydroxypropylcellulose (HPC) in water have been investigated. Measurements have been performed by using a variety of different apparatuses with cone and plate geometries. Particular attention has been devoted to the experimental procedures, including the use of different sealing techniques, which are necessary to avoid solvent evaporation during the very long

N. Grizzuti; P. Moldenaers; M. Mortier; J. Mewis

1993-01-01

214

Countermeasures for Space Radiation Induced Malignancies and Acute Biological Effects  

NASA Astrophysics Data System (ADS)

The hypothesis being evaluated in this research program is that control of radiation induced oxidative stress will reduce the risk of radiation induced adverse biological effects occurring as a result of exposure to the types of radiation encountered during space travel. As part of this grant work, we have evaluated the protective effects of several antioxidants and dietary supplements and observed that a mixture of antioxidants (AOX), containing L-selenomethionine, N-acetyl cysteine (NAC), ascorbic acid, vitamin E succinate, and alpha-lipoic acid, is highly effective at reducing space radiation induced oxidative stress in both in vivo and in vitro systems, space radiation induced cytotoxicity and malignant transformation in vitro [1-7]. In studies designed to determine whether the AOX formulation could affect radiation induced mortality [8], it was observed that the AOX dietary supplement increased the 30-day survival of ICR male mice following exposure to a potentially lethal dose (8 Gy) of X-rays when given prior to or after animal irradiation. Pretreatment of animals with antioxidants resulted in significantly higher total white blood cell and neutrophil counts in peripheral blood at 4 and 24 hours following exposure to doses of 1 Gy and 8 Gy. Antioxidant treatment also resulted in increased bone marrow cell counts following irradiation, and prevented peripheral lymphopenia following 1 Gy irradiation. Supplementation with antioxidants in irradiated animals resulted in several gene expression changes: the antioxidant treatment was associated with increased Bcl-2, and decreased Bax, caspase-9 and TGF-?1 mRNA expression in the bone marrow following irradiation. These results suggest that modulation of apoptosis may be mechanistically involved in hematopoietic system radioprotection by antioxidants. Maintenance of the antioxidant diet was associated with improved recovery of the bone marrow following sub-lethal or potentially lethal irradiation. Taken together, oral supplementation with antioxidants appears to be an effective approach for the radioprotection of hematopoietic cells against the cell killing effects of radiation, and for improving survival in irradiated animals. Preliminary data suggest similar antioxidant protective effects for animals exposed to potentially lethal doses of proton radiation. Studies were also performed to determine whether dietary antioxidants could affect the incidence rates of malignancies in CBA mice exposed to 300 cGy proton (1 GeV/n) radiation or 50 cGy iron ion (1 GeV/n) radiation [9]. Two antioxidant formulations were utilized in these studies; an AOX formulation containing the mixture of antioxidant agents developed from our previous studies and an antioxidant dietary formulation containing the soybean-derived protease inhibitor known as the Bowman-Birk inhibitor (BBI). BBI was evaluated in the form of BBI Concentrate (BBIC), which is the form of BBI utilized in human trials. BBIC has been utilized in human trials since 1992, as described [10]. The major finding in the long-term animal studies was that there was a reduced risk of malignant lymphoma in mice exposed to space radiations and maintained on diets containing the antioxidant formulations. In addition, the two different dietary countermeasures also reduced the yields of a variety of different rare tumor types, arising from both epithelial and connective tissue cells, observed in the animals exposed to space radiation. REFERENCES [1] Guan J. et al (2004) Radiation Research 162, 572-579. [2] Wan X.S. et al (2005) Radiation Research 163, 364-368. [3] Wan X.S. et al (2005) Radiation Research 163, 232-240. [4] Guan J. et al (2006) Radiation Research 165, 373-378. [5] Wan X.S. et al (2006) International Journal of Radiation Oncology, Biology, Physics 64, 1475-1481. [6] Kennedy A.R. et al (2006) Radiation Research 166, 327-332. [7] Kennedy A.R. et al (2007) Radiation & Environmental Biophysics 46(2), 201-3. [8]Wambi, C., Sanzari, J., Wan, X.S., Nuth, M., Davis, J., Ko, Y.-H., Sayers, C.M., Baran, M., Ware, J.H. and Kennedy, A

Kennedy, Ann

215

Targets for, and consequences of, radiation-induced chromosomal instability  

NASA Astrophysics Data System (ADS)

Chromosomal instability has been demonstrated in a human- hamster hybrid cell line, GM10115, after exposure to x- rays. Chromosomal instability in these cells is characterized by the appearance of novel chromosomal rearrangements multiple generations after exposure to ionizing radiation. To identify the cellular target(s) for radiation-induced chromosomal instability, cells were treated with 125I-labeled compounds. Labeling cells with 125I-iododeoxyuridine, which caused radiation damage to the DNA and associated nuclear structures, did induce chromosomal instability. While cell killing and first-division chromosomal rearrangements increased with increasing numbers of 125I decays, the frequency of chromosomal instability was independent of dose. Incorporation of an 125I-labeled protein, 125I-succinyl- concanavalin A, into either the plasma membrane or the cytoplasm, failed to elicit chromosomal instability. These results show that radiation damage to the nucleus, and not to extranuclear regions, contributes to the induction of chromosomal instability. To determine the role of DNA strand breaks as a molecular lesion responsible for initiating chromosomal instability, cells were treated with a variety of DNA strand breaking agents. Agents capable of producing complex DNA double strand breaks, including X-rays, Neocarzinostatin and bleomycin, were able to induce chromosomal instability. In contrast, double strand breaks produced by restriction endonucleases as well as DNA strand breaks produced by hydrogen peroxide failed to induce chromosomal instability. This demonstrates that the type of DNA breakage is important in the eventual manifestation of chromosomal instability. In order to understand the relationship between chromosomal instability and other end points of genomic instability, chromosomally stable and unstable clones were analyzed for sister chromatid exchange, delayed reproductive cell death, delayed mutation, mismatch repair and delayed gene amplification. Although individual clones within each group were significantly different from unirradiated clones for many of the endpoints, there was no significant correlation between chromosomal instability and the phenotypes of sister chromatid exchange, delayed mutation, and mismatch repair. Delayed gene amplification weakly correlated chromosomal instability (0.05 < p < 0.1) and delayed reproductive cell death correlated strongly (p < 0.05) with chromosomal instability. These data indicate that multiple pathways exist for inducing genomic instability in GM10115 cells after radiation exposure.

Kaplan, Mark Isaac

216

Dynamics of the UV-Induced Absorption of Laser Light by Color Centers in Crystalline KY3F10:Ce3+,Yb3+  

NASA Astrophysics Data System (ADS)

A pump-probe method is used to study the dynamics of the destruction of color centers in KY3F10:Ce3+ and KY3F10:Ce3+,Yb3+ crystals by continuous UV radiation and to measure its parameters. The effect of Yb3+ ions in crystalline KY3F10:Ce3+,Yb3+ on the rate of bleaching of color centers in it under exposure to the probe light is studied. Irradiation of KY3F10:Ce3+ and KY3F10:Ce3+,Yb3+ crystals at a wavelength corresponding to an absorption band of a color center accelerates the destruction of the color centers and the reduction of Yb2+ ions to the trivalent state in proportion to the density of the radiation. A model is constructed for the bleaching mechanism that can be used to estimate the ionization cross section of the color centers.

Morozov, O. A.; Naumov, A. K.; Tselisheva, E. Yu.; Lovchev, A. V.; Korableva, S. L.

2014-09-01

217

Radiation Induced Bystander Effects in Mice Given Low Doses of Radiation in Vivo  

PubMed Central

The ‘bystander effect’ phenomenon has challenged the traditional framework for assessing radiation damage by showing radiation induced changes in cells which have not been directly targeted, but are neighbors to or receive medium from directly hit cells. Our group performed a range of single and serial low dose irradiations on two genetically distinct strains of mice. Bladder explants established from these mice were incubated in culture medium, which was used to measure death responses in a keratinocyte reporter system. The study revealed that the medium harvested from bladder tissues’ (ITCM) from acutely irradiated C57BL6 but not Balb/c mice, was able to induce clonogenic death. Administration of a priming dose(s) before a challenge dose to both C57BL6 and Balb/c mice stimulated reporter cell survival irrespective of the time interval between dose(s) delivery. When ITCM corresponding to both strains of mice was measured for its calcium mobilization inducing ability, results showed an elevation in intracellular calcium levels that was strain dependent. This indicates that genotype determined the type of bystander signal/response that was produced after exposure to low and acute doses of radiation. However, serial exposure conditions modified bystander signal production to induce similar effects that were characterized by excessive growth. PMID:21731538

Singh, Harleen; Saroya, Rohin; Smith, Richard; Mantha, Rebecca; Guindon, Lynda; Mitchel, Ron E.J.; Seymour, Colin; Mothersill, Carmel

2010-01-01

218

Radiation-Induced Leukemia at Doses Relevant to Radiation Therapy: Modeling Mechanisms and Estimating Risks  

NASA Technical Reports Server (NTRS)

Because many cancer patients are diagnosed earlier and live longer than in the past, second cancers induced by radiation therapy have become a clinically significant issue. An earlier biologically based model that was designed to estimate risks of high-dose radiation induced solid cancers included initiation of stem cells to a premalignant state, inactivation of stem cells at high radiation doses, and proliferation of stem cells during cellular repopulation after inactivation. This earlier model predicted the risks of solid tumors induced by radiation therapy but overestimated the corresponding leukemia risks. Methods: To extend the model to radiation-induced leukemias, we analyzed in addition to cellular initiation, inactivation, and proliferation a repopulation mechanism specific to the hematopoietic system: long-range migration through the blood stream of hematopoietic stem cells (HSCs) from distant locations. Parameters for the model were derived from HSC biologic data in the literature and from leukemia risks among atomic bomb survivors v^ ho were subjected to much lower radiation doses. Results: Proliferating HSCs that migrate from sites distant from the high-dose region include few preleukemic HSCs, thus decreasing the high-dose leukemia risk. The extended model for leukemia provides risk estimates that are consistent with epidemiologic data for leukemia risk associated with radiation therapy over a wide dose range. For example, when applied to an earlier case-control study of 110000 women undergoing radiotherapy for uterine cancer, the model predicted an excess relative risk (ERR) of 1.9 for leukemia among women who received a large inhomogeneous fractionated external beam dose to the bone marrow (mean = 14.9 Gy), consistent with the measured ERR (2.0, 95% confidence interval [CI] = 0.2 to 6.4; from 3.6 cases expected and 11 cases observed). As a corresponding example for brachytherapy, the predicted ERR of 0.80 among women who received an inhomogeneous low-dose-rate dose to the bone marrow (mean = 2.5 Gy) was consistent with the measured ERR (0.62, 95% Cl =-0.2 to 1.9). Conclusions: An extended, biologically based model for leukemia that includes HSC initiation, inactivation, proliferation, and, uniquely for leukemia, long-range HSC migration predicts, %Kith reasonable accuracy, risks for radiationinduced leukemia associated with exposure to therapeutic doses of radiation.

Shuryak, Igor; Sachs, Rainer K.; Hlatky, Lynn; Mark P. Little; Hahnfeldt, Philip; Brenner, David J.

2006-01-01

219

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

220

Lack of photoprotection against UVB-induced erythema by immediate pigmentation induced by 382 nm radiation  

SciTech Connect

Immediate pigment darkening (IPD) was induced on the backs of 11 human volunteers of skin types III and IV by exposing the skin to UVA radiation (382 nm). The minimum erythema dose (MED) of UVB radiation was also determined by exposing sites to graduated doses of 304 nm radiation. The order of exposure of distinct anatomic areas was as follow: UVB followed by IPD induction; IPD induction followed by UVB; IPD induction followed 3 h later by UVB; and UVB only. Erythema responses induced by UVB were graded by inspection 24 h later and the MEDs in the 4 areas were compared. The induction of IPD before UVB exposure caused no significant change in the MED compared to sites receiving UVB only, or receiving UVA radiation after UVB, confirming that the IPD reaction does not protect against UVB-induced erythema. There was also no evidence of photorecovery, i.e., an increase in the MED of UVB resulting from exposure to longer wavelength, UV or visible radiation following UVB exposure.

Black, G.; Matzinger, E.; Gange, R.W.

1985-11-01

221

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

222

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

223

Sensitivity to Radiation-Induced Cancer in Hemochromatosis  

SciTech Connect

The objectives of this pilot project using HFE-knockout homozygotes and heterozygotes are to (1) determine whether the knock-out mice have greater sensitivity to radiation-induced cancer of the colon, liver and breast, (2) establish the dependence of this sensitivity on the accumulation of iron, (3) determine the extent to which cell replication and apoptosis occur in these target tissues with varying iron load, and (4) correlate the increases in sensitivity with changes in insulin-related signaling in tumors and normal tissue from each target organ. Three experimental designs will be used in the pilot project. The sequence of experiments is designed to first explore the influence of iron load on the response and demonstrate that HFE knockout mice are more sensitive than the wild type to radiation-induced cancer in one or more of three target tissues (liver, colon and breast). The dose response relationships with a broader set of radiation doses will be explored in the second experiment. The final experiment is designed to explore the extent to which heterozygotes display the increased susceptibility to cancer induction and to independently assess the importance of iron load to the initiation versus promotion of tumors.

Bull. Richard J.; Anderson, Larry E.

2000-06-01

224

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. PMID:18521195

1997-01-01

225

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

226

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. PMID:21859013

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

2011-01-01

227

G2-chromosome aberrations induced by high-LET radiations.  

PubMed

We report measurement of initial G2-chromatid breaks in normal human fibroblasts exposed to various types of high-LET particles. Exponentially growing AG 1522 cells were exposed to gamma rays or heavy ions. Chromosomes were prematurely condensed by calyculin A. Chromatid-type breaks and isochromatid-type breaks were scored separately. The dose response curves for the induction of total chromatid breaks (chromatid-type + isochromatid-type) and chromatid-type breaks were linear for each type of radiation. However, dose response curves for the induction of isochromatid-type breaks were linear for high-LET radiations and linear-quadratic for gamma rays. Relative biological effectiveness (RBE), calculated from total breaks, showed a LET dependent tendency with a peak at 55 keV/micrometer silicon (2.7) or 80 keV/micrometer carbon (2.7) and then decreased with LET (1.5 at 440 keV/micrometer). RBE for chromatid-type break peaked at 55 keV/micrometer (2.4) then decreased rapidly with LET. The RBE of 440 keV/micrometer iron particles was 0.7. The RBE calculated from induction of isochromatid-type breaks was much higher for high-LET radiations. It is concluded that the increased production of isochromatid-type breaks, induced by the densely ionizing track structure, is a signature of high-LET radiation exposure. PMID:11642300

Kawata, T; Durante, M; Furusawa, Y; George, K; Ito, H; Wu, H; Cucinotta, F A

2001-01-01

228

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

229

Debris and Radiation-Induced Damage Effects on EUV Nanolithography Source Collector Mirror Optics Performance  

E-print Network

Debris and Radiation-Induced Damage Effects on EUV Nanolithography Source Collector Mirror Optics-based EUV light sources to debris (fast ions, neutrals, off-band radiation, droplets) remains one sputtering. In this paper we study several aspects of debris and radiation-induced damage to candidate EUVL

Harilal, S. S.

230

Mechanism of radiation-induced bystander effect: Role of the cyclooxygenase-2 signaling pathway  

E-print Network

Mechanism of radiation-induced bystander effect: Role of the cyclooxygenase-2 signaling pathway 25, 2005 (received for review June 30, 2005) The radiation-induced bystander effect is defined are likely to be directly dam- aged, the deleterious effect of radiation is expected to decline

Brenner, David Jonathan

231

Pressure-induced superconducting state in crystalline boron nanowires Liling Sun,1,*, Takahiro Matsuoka,2 Yasuyuki Tamari,2 Katsuya Shimizu,2,*, Jifa Tian,1 Yuan Tian,1 Chendong Zhang,1  

E-print Network

Pressure-induced superconducting state in crystalline boron nanowires Liling Sun,1,*, Takahiro February 2009; published 16 April 2009 We report high-pressure induced superconductivity in boron nanowires-B , these BNWs show a semiconductor- metal transition at much lower pressure than bulk -r-B. Also, we found

Gao, Hongjun

232

Erythrocyte Stiffness during Morphological Remodeling Induced by Carbon Ion Radiation  

PubMed Central

The adverse effect induced by carbon ion radiation (CIR) is still an unavoidable hazard to the treatment object. Thus, evaluation of its adverse effects on the body is a critical problem with respect to radiation therapy. We aimed to investigate the change between the configuration and mechanical properties of erythrocytes induced by radiation and found differences in both the configuration and the mechanical properties with involving in morphological remodeling process. Syrian hamsters were subjected to whole-body irradiation with carbon ion beams (1, 2, 4, and 6 Gy) or X-rays (2, 4, 6, and 12 Gy) for 3, 14 and 28 days. Erythrocytes in peripheral blood and bone marrow were collected for cytomorphological analysis. The mechanical properties of the erythrocytes were determined using atomic force microscopy, and the expression of the cytoskeletal protein spectrin-?1 was analyzed via western blotting. The results showed that dynamic changes were evident in erythrocytes exposed to different doses of carbon ion beams compared with X-rays and the control (0 Gy). The magnitude of impairment of the cell number and cellular morphology manifested the subtle variation according to the irradiation dose. In particular, the differences in the size, shape and mechanical properties of the erythrocytes were well exhibited. Furthermore, immunoblot data showed that the expression of the cytoskeletal protein spectrin-?1 was changed after irradiation, and there was a common pattern among its substantive characteristics in the irradiated group. Based on these findings, the present study concluded that CIR could induce a change in mechanical properties during morphological remodeling of erythrocytes. According to the unique characteristics of the biomechanical categories, we deduce that changes in cytomorphology and mechanical properties can be measured to evaluate the adverse effects generated by tumor radiotherapy. Additionally, for the first time, the current study provides a new strategy for enhancing the assessment of the curative effects and safety of clinical radiotherapy, as well as reducing adverse effects. PMID:25401336

Zhang, Baoping; Liu, Bin; Zhang, Hong; Wang, Jizeng

2014-01-01

233

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

234

Radiation-induced premelting of ice at silica interfaces.  

PubMed

The existence of surface and interfacial melting of ice below 0 degrees C has been confirmed by many different experimental techniques. Here we present a high-energy x-ray reflectivity study of the interfacial melting of ice as a function of both temperature and x-ray irradiation dose. We found a clear increase of the thickness of the quasiliquid layer with the irradiation dose. By a systematic x-ray study, we have been able to unambiguously disentangle thermal and radiation-induced premelting phenomena. We also confirm the previously announced very high water density (1.25 g/cm(3)) within the emerging quasiliquid layer. PMID:19792807

Schöder, S; Reichert, H; Schröder, H; Mezger, M; Okasinski, J S; Honkimäki, V; Bilgram, J; Dosch, H

2009-08-28

235

Investigation Into Radiation-Induced Compaction of Zerodur (trademark)  

NASA Technical Reports Server (NTRS)

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.

1996-01-01

236

Facial reconstruction for radiation-induced skin cancer  

SciTech Connect

Radiation-induced skin cancers can be difficult to diagnose and treat. Typically, a patient who has received orthovoltage radiotherapy for disorders such as acne, eczema, tinea capitis, skin tuberculosis, and skin cancer can expect that aggressive skin cancers and chronic radiodermatitis may develop subsequently. Cryptic facial cancers can lead to metastases and death. Prophylactic widefield excision of previously irradiated facial skin that has been subject to multiple recurrent skin cancers is suggested as a method of deterring future cutaneous malignancy and metastases. The use of tissue expanders and full-thickness skin grafts offers an expedient and successful method of subsequent reconstruction.

Panje, W.R.; Dobleman, T.J. (Univ. of Chicago, IL (USA))

1990-04-01

237

Transient radiation-induced absorption in laser materials  

SciTech Connect

Transient radiation-induced absorption losses in laser materials have been measured using a pulsed nuclear reactor. Reactor pulse widths of 70 to 90 {mu}s and absorbed doses of 1 to 7.5 krad have been used. Transmission recovery times and peak absorption coefficients are given. Materials tested include LiNbO{sub 3}, GSGG, silica substrates, and filter glasses used in the laser cavity. The filter glasses are tested at discrete wavelengths in the range 440--750 nm. Lithium niobate , MgO doped LiNbO{sub 3}, GSGG, and the silica substrates are tested at 1061 nm.

Brannon, P.J.

1994-12-31

238

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

239

Measurements of prompt radiation induced conductivity in Teflon (PTFE).  

SciTech Connect

We performed measurements of the prompt radiation induced conductivity (RIC) in thin samples of Teflon (PTFE) at the Little Mountain Medusa LINAC facility in Ogden, UT. Three mil (76.2 microns) samples were irradiated with a 0.5 %CE%BCs pulse of 20 MeV electrons, yielding dose rates of 1E9 to 1E11 rad/s. We applied variable potentials up to 2 kV across the samples and measured the prompt conduction current. Details of the experimental apparatus and analysis are reported in this report on prompt RIC in Teflon.

Hartman, E. Frederick; Zarick, Thomas Andrew; Sheridan, Timothy J.; Preston, E. [ITT Exelis Mission Systems, Colorado Springs, CO

2013-05-01

240

Heat Induced Damage Detection by Terahertz (THz) Radiation  

NASA Astrophysics Data System (ADS)

Terahertz (THz) and sub-terahertz imaging and spectroscopy are becoming increasingly popular nondestructive evaluation techniques for damage detection and characterization of materials. THz radiation is being used for inspecting ceramic foam tiles used in TPS (Thermal Protection System), thick polymer composites and polymer tiles that are not good conductors of ultrasonic waves. Capability of THz electromagnetic waves in detecting heat induced damage in porous materials is investigated in this paper. Porous pumice stone blocks are subjected to long time heat exposures to produce heat induced damage in the block. The dielectric properties extracted from THz TDS (Time Domain Spectroscopy) measurements are compared for different levels of heat exposure. Experimental results show noticeable and consistent change in dielectric properties with increasing levels of heat exposure, well before its melting point.

Rahani, Ehsan Kabiri; Kundu, Tribikram; Wu, Ziran; Xin, Hao

2011-06-01

241

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

242

Follistatin Is Induced by Ionizing Radiation and Potentially Predictive of Radiosensitivity in Radiation-Induced Fibrosis Patient Derived Fibroblasts  

PubMed Central

Follistatin is a potent regulator of the inflammatory response and binds to and inhibits activin A action. Activin A is a member of the TGF? protein superfamily which has regulatory roles in the inflammatory response and in the fibrotic process. Fibrosis can occur following cell injury and cell death induced by agents such as ionizing radiation (IR). IR is used to treat cancer and marked fibrotic response is a normal tissue (non-tumour) consequence in a fraction of patients under the current dose regimes. The discovery and development of a therapeutic to abate fibrosis in these radiosensitive patients would be a major advance for cancer radiotherapy. Likewise, prediction of which patients are susceptible to fibrosis would enable individualization of treatment and provide an opportunity for pre-emptive fibrosis control and better tumour treatment outcomes. The levels of activin A and follistatin were measured in fibroblasts derived from patients who developed severe radiation-induced fibrosis following radiotherapy and compared to fibroblasts from patients who did not. Both follistatin and activin A gene expression levels were increased following IR and the follistatin gene expression level was lower in the fibroblasts from fibrosis patients compared to controls at both basal levels and after IR. The major follistatin transcript variants were found to have a similar response to IR and both were reduced in fibrosis patients. Levels of follistatin and activin A secreted in the fibroblast culture medium also increased in response to IR and the relative follistatin protein levels were significantly lower in the samples derived from fibrosis patients. The decrease in the follistatin levels can lead to an increased bioactivity of activin A and hence may provide a useful measurement to identify patients at risk of a severe fibrotic response to IR. Additionally, follistatin, by its ability to neutralise the actions of activin A may be of value as an anti-fibrotic for radiation induced fibrosis. PMID:24204752

McKay, Michael J.; Leong, Trevor; de Kretser, David M.; Sprung, Carl N.

2013-01-01

243

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

244

Gossypol enhances radiation induced autophagy in glioblastoma multiforme.  

PubMed

Malignant gliomas (glioblastoma multiforme) are the most aggressive of the primary brain tumors. Radiotherapy is an important tool for treatment of cancer but malignant gliomas are usually resistant to radiotherapy and other adjuvant therapies. Thus new drugs are needed to increase the efficiency of radiotherapy in order to improve the therapeutic outcome of tumor patients. Recent investigations showed that gossypol, natural polyphenolic compound produced by cotton plants, is a promising agent against solid tumors. The current study was defined to evaluate whether the combinatorial effect of radiation and gossypol would induce higher level of cell death on U-87 MG than single agent treatment and its possible mechanism of action. Clonogenic survival assay showed that ionizing radiation plus gossypol significantly inhibited clonogenic growth of irradiated cells as compared with either treatment alone. Acridine orange/etidium bromide staining confirmed that there was no significant increase in necrotic and apoptotic cells, but irradiated cells in combination with gossypol showed a significant increase in accumulation of acidic vesicular organelle. The results obtained herein indicated that gossypol is a promising drug that induced autophagic cell death in radioresistant malignant glioma. PMID:24968413

Keshmiri-Neghab, Hoda; Goliaei, Bahram; Nikoofar, Alireza

2014-10-01

245

Temperature Dependence of Radiation Induced Conductivity in Insulators  

SciTech Connect

This study measures Radiation Induced Conductivity (RIC) of Low Density Polyethylene (LDPE) over temperatures ranging from {approx}110 K to {approx}350 K. RIC occurs when incident ionizing radiation deposits energy and excites electrons into the conduction band of insulators. Conductivity was measured when a voltage was applied across vacuum-baked, thin film LDPE polymer samples in a parallel plate geometry. RIC was calculated as the difference in sample conductivity under no incident radiation and under an incident {approx}4 MeV electron beam at low incident fluxes of 10{sup -4}-10{sup -1} Gr/sec. The steady-state RIC was found to agree well with the standard power law relation, {sigma}{sub RIC} = k{sub RIC}{center_dot}D ring {sup {delta}} between conductivity, {sigma} and adsorbed dose rate, D ring . Both the proportionality constant, k{sub RIC}, and the power, {delta}, were found to be temperature dependant above {approx}250 K, with behavior consistent with photoconductivity models developed for localized trap states in disordered semiconductors. Below {approx}250 K, kRIC and {delta} exhibited little change. The observed difference in temperature dependence might be related to a structural phase transition seen at T{sub {beta}}{approx}256 K in prior studies of mechanical and thermodynamic properties of LDPE.

Dennison, J. R.; Gillespie, Jodie; Hodges, Joshua; Hoffmann, R. C.; Abbott, J.; Hart, Steven [Physics Department, Utah State University 4415 Old Main Hill, Logan, UT 84322 (United States); Hunt, Alan W. [Idaho Accelerator Center, Idaho State University, Pocatello, ID 83209 (United States)

2009-03-10

246

Proton-induced radiation damage in germanium detectors  

SciTech Connect

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{sub 8} protons cm{sup {minus}2} (proton energy: 1.5 GeV) at different operating temperatures (90 to 120 K) to induce radiation damage. Basic scientific as well as 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 T {le} 110{degrees}C while staying specially designed cryostats. This paper shows that n-type HPGe detectors can be used in charged particles 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.

Bruckner, J.; Korfer, M.; Wanke, H. (Max-Planck-Institut fuer Chemie (Otto-Hahn-Institut), Mainz (Germany)); Schroeder, A.N.F. (Univ. zu Koln, D-5000 Koln 41 (DE)); Figes, D.; Dragovitsch, P. (Inst. fur Kernphysik, KFA Julich, D-5170 Julich (DE)); Englert, P.A.J. (San Jose State Univ., CA (United States)); Starr, R.; Trombka, J.I. (National Aeronautics and Space Administration, Greenbelt, MD (United States). Goddard Space Flight Center); Taylor, I. (Princeton Gamma-Tech, Princeton, NJ (US)); Drake, D.M.; Shunk, E.R. (Los Alamos National Lab., NM (United States))

1991-04-01

247

Radiation induced thyroid neoplasms 1920 to 1987: A vanishing problem  

SciTech Connect

Radiation for benign diseases has been implicated as an etiologic factor in thyroid cancer. From 1930-60, over 2 million children may have been exposed to therapeutic radiation and it is estimated that up to 7% may develop thyroid cancer after a 5-40 year latency. Thyroid stimulating hormone, secondary to radioinduced hypothyroidism, has been implicated as causative in animals. Such data has led to expensive screening programs in high risk patients. Because of a decline in irradiation for benign diseases in children over the last 2 decades, we questioned whether the incidence of radiation induced thyroid neoplasms (RITN) was also decreasing. Twenty-six of 227 patients (11%) with thyroid malignancies seen at our institution from 1974-87 had a history of previous head and neck irradiation. These included 13 papillary, 3 follicular, and 7 mixed carcinomas as well as 2 lymphomas and 1 synovial cell sarcoma. None of these 26 patients had abnormal thyroid function tests at presentation. Mean latency from irradiation to the diagnosis of thyroid cancer was 25.4 years (6-55 year range). Compared to the reported increasing incidence of RITN from 1940-70, there appears to be a significant decrease since 1970. Based on our analysis, the use of expensive screening programs in high risk populations may no longer be warranted. Additionally, the routine use of thyroid replacement in previously irradiated chemically hypothyroid patients is not recommended.30 references.

Mehta, M.P.; Goetowski, P.G.; Kinsella, T.J.

1989-06-01

248

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

249

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

250

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. PMID:23909719

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

2014-01-01

251

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

252

Ionizing radiation induces tumor cell lysyl oxidase secretion  

PubMed Central

Background Ionizing radiation (IR) is a mainstay of cancer therapy, but irradiation can at times also lead to stress responses, which counteract IR-induced cytotoxicity. IR also triggers cellular secretion of vascular endothelial growth factor, transforming growth factor ? and matrix metalloproteinases, among others, to promote tumor progression. Lysyl oxidase is known to play an important role in hypoxia-dependent cancer cell dissemination and metastasis. Here, we investigated the effects of IR on the expression and secretion of lysyl oxidase (LOX) from tumor cells. Methods LOX-secretion along with enzymatic activity was investigated in multiple tumor cell lines in response to irradiation. Transwell migration assays were performed to evaluate invasive capacity of naïve tumor cells in response to IR-induced LOX. In vivo studies for confirming IR-enhanced LOX were performed employing immunohistochemistry of tumor tissues and ex vivo analysis of murine blood serum derived from locally irradiated A549-derived tumor xenografts. Results LOX was secreted in a dose dependent way from several tumor cell lines in response to irradiation. IR did not increase LOX-transcription but induced LOX-secretion. LOX-secretion could not be prevented by the microtubule stabilizing agent patupilone. In contrast, hypoxia induced LOX-transcription, and interestingly, hypoxia-dependent LOX-secretion could be counteracted by patupilone. Conditioned media from irradiated tumor cells promoted invasiveness of naïve tumor cells, while conditioned media from irradiated, LOX- siRNA-silenced cells did not stimulate their invasive capacity. Locally applied irradiation to tumor xenografts also increased LOX-secretion in vivo and resulted in enhanced LOX-levels in the murine blood serum. Conclusions These results indicate a differential regulation of LOX-expression and secretion in response to IR and hypoxia, and suggest that LOX may contribute towards an IR-induced migratory phenotype in sublethally-irradiated tumor cells and tumor progression. PMID:25052686

2014-01-01

253

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

254

Chemoprevention of ultraviolet radiation-induced skin cancer.  

PubMed Central

The use of chemical and physical sunscreening agents has increased dramatically during the last two to three decades as an effective means of preventing sunbum. The use of high sunprotection factor sunscreens has also been widely promoted for the prevention of skin cancer, including melanoma. Whereas sunscreens are undoubtedly effective in preventing sunbum, their efficacy in preventing skin cancer, especially melanoma, is currently under considerable debate. Sunscreens have been shown to prevent the induction of DNA damage that presumably results from the direct effects of ultraviolet radiation (UVR) on DNA. DNA damage has been identified as an initiator of skin cancer formation. However, both laboratory and epidemiological studies indicate that sunscreens may not block the initiation or promotion of melanoma formation. These studies suggest that the action spectrum for erythema induction is different than the action spectrum for the induction of melanoma. Indeed, recent reports on the wavelength dependency for the induction of melanoma in a fish model indicate that the efficacy of ultraviolet A wavelengths (320-400 nm) to induce melanoma is orders of magnitude higher than would be predicted from the induction of erythema in man or nonmelanoma skin tumors in mice. Other strategies for the chemoprevention of skin cancer have also been reported. Low levels and degree of unsaturation of dietary fats protect against UVR-induced skin cancer in mice humens. Compounds with antioxidant activity, including green tea extracts (polyphenols), have been reported to inhibit UVR-induced skin carcinogenesis. PMID:9255591

Ley, R D; Reeve, V E

1997-01-01

255

Crystalline phase transition information induced by high temperature susceptibility transformations in bulk PMP-YBCO superconductor growth in-situ  

NASA Astrophysics Data System (ADS)

The dynamic susceptibility transformations of bulk HTSC PMP-YBCO growth have been investigated from 200 °C up to 1060 °C by the Faraday Balance in-situ. It revealed that the crystalline phase transitions of bulk PMP-YBCO growth in process. A new discovery of Y123 phase pre-formed then melted in heating stage has been found. It also discovered that Y123 crystal solidification started at 1004 °C in cooling stage. Before Y123 solidification the liquid phase CuO change to Cu2O reciprocally as well as the copper ion valence changed between divalent Cu2+ and trivalent Cu1+ each other. It was essential to keep quantities of CuO phase instead of the Cu2O for Y123 crystal solidification.

Zhang, C. P.; Chaud, X.; Beaugnon, E.; Zhou, L.

2015-01-01

256

Molecular-dynamics simulations of stacking-fault-induced dislocation annihilation in prestrained ultrathin single-crystalline copper films  

SciTech Connect

We report results of large-scale molecular-dynamics simulations of dynamic deformation under biaxial tensile strain of prestrained single-crystalline nanometer-scale-thick face-centered cubic (fcc) copper films. Our results show that stacking faults, which are abundantly present in fcc metals, may play a significant role in the dissociation, cross slip, and eventual annihilation of dislocations in small-volume structures of fcc metals. The underlying mechanisms are mediated by interactions within and between extended dislocations that lead to annihilation of Shockley partial dislocations or formation of perfect dislocations. Our findings demonstrate dislocation starvation in small-volume structures with ultrathin film geometry, governed by a mechanism other than dislocation escape to free surfaces, and underline the significant role of geometry in determining the mechanical response of metallic small-volume structures.

Kolluri, Kedarnath; Gungor, M. Rauf; Maroudas, Dimitrios [Department of Chemical Engineering, University of Massachusetts, Amherst, Massachusetts 01003-3110 (United States)

2009-05-01

257

Superconductivity induced by In substitution into the topological crystalline insulator Pb0.5Sn0.5Te  

NASA Astrophysics Data System (ADS)

Indium substitution turns the topological crystalline insulator (TCI) Pb0.5Sn0.5Te into a possible topological superconductor. To investigate the effect of the indium concentration on the crystal structure and superconducting properties of (Pb0.5Sn0.5)1-xInxTe, we have grown high-quality single crystals using a modified floating-zone method and have performed systematic studies for indium content in the range 0?x?0.35. We find that the single crystals retain the rocksalt structure up to the solubility limit of indium (x ˜0.30). Experimental dependencies of the superconducting transition temperature (Tc) and the upper critical magnetic field (Hc2) on the indium content x have been measured. The maximum Tc is determined to be 4.7 K at x =0.30, with ?0Hc2(T =0)?5 T.

Zhong, R. D.; Schneeloch, J. A.; Liu, T. S.; Camino, F. E.; Tranquada, J. M.; Gu, G. D.

2014-07-01

258

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

E-print Network

In \\u{C}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 {\\itshape 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 \\u{C}erenkov radiation and transition radiation, which may pave the way to investigate new schemes of transferring evanescent wave to radiation.

Liu, Yangjie

2013-01-01

259

The effect of Halofuginone in the amelioration of radiation induced-lung fibrosis.  

PubMed

The lung is one of the most sensitive organs to ionizing radiation, and damage to normal lung tissue remains a major dose limiting factor for patients receiving radiation to the thorax. Radiation induced lung injury (RILI) which is also named as "radiation pneumonpathy" is a continuous process and regarded as the result of an abnormal healing response. It has been shown that transforming growth factor ?-1 (TGF-?1) plays an integral role in the radiation induced lung fibrosis formation by promoting the chemoattraction of fibroblasts and their conversion to myofibroblasts. Halofuginone is a, low molecular weight plant derived alkaloid, isolated from the Dichroa febrifuga plant that exhibits antifibrotic activity and inhibition of type I collagen synthesis. Halofuginone has been shown to protect against radiation induced soft tissue fibrosis by virtue of inhibiting various members of TFG-? signaling pathway. By the light of these findings, we hypothesize that Halofuginone may be able to ameliorate the radiation induced lung fibrosis. PMID:23352286

Yavas, Guler; Calik, Mustafa; Calik, Goknil; Yavas, Cagdas; Ata, Ozlem; Esme, Hidir

2013-04-01

260

Radiation effects in ice: New results  

NASA Astrophysics Data System (ADS)

Studies of radiation effects in ice are motivated by intrinsic interest and by applications in astronomy. Here we report on new and recent results on radiation effects induced by energetic ions in ice: amorphization of crystalline ice, compaction of microporous amorphous ice, electrostatic charging and dielectric breakdown and correlated structural/chemical changes in the irradiation of water-ammonia ices.

Baragiola, R. A.; Famá, M.; Loeffler, M. J.; Raut, U.; Shi, J.

2008-06-01

261

Radiation-induced segregation and phase stability in ferritic-martensitic alloy T 91  

NASA Astrophysics Data System (ADS)

Radiation-induced segregation in ferritic-martensitic alloy T 91 was studied to understand the behavior of solutes as a function of dose and temperature. Irradiations were conducted using 2 MeV protons to doses of 1, 3, 7 and 10 dpa at 400 °C. Radiation-induced segregation at prior austenite grain boundaries was measured, and various features of the irradiated microstructure were characterized, including grain boundary carbide coverage, the dislocation microstructure, radiation-induced precipitation and irradiation hardening. Results showed that Cr, Ni and Si segregate to prior austenite grain boundaries at low dose, but segregation ceases and redistribution occurs above 3 dpa. Grain boundary carbide coverage mirrors radiation-induced segregation. Irradiation induces formation of Ni-Si-Mn and Cu-rich precipitates that account for the majority of irradiation hardening. Radiation-induced segregation behavior is likely linked to the evolution of the precipitate and dislocation microstructures.

Wharry, Janelle P.; Jiao, Zhijie; Shankar, Vani; Busby, Jeremy T.; Was, Gary S.

2011-10-01

262

Radiation-induced attenuation of high-OH optical fibers after hydrogen treatment in the presence of ionizing radiation  

SciTech Connect

High purity, high-OH, optical fibers were irradiated in a hydrogen atmosphere to explore hydrogen binding into defects created by the ionizing radiation. Significant improvements in subsequent measurements of radiation-induced attenuation were observed. 18 refs., 4 figs., 2 tabs.

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

1991-01-01

263

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

264

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

265

Characterization of gamma radiation inducible thioredoxin h from Spirogyra varians.  

PubMed

In this study, thioredoxin h (Trxh) was isolated and characterized from the fresh water green alga Spirogyra varians, which was one amongst the pool of proteins induced upon gamma radiation treatment. cDNA clones encoding S. varians thioredoxin h were isolated from a pre-constructed S. varians cDNA library. Trxh had a molecular mass of 13.5kDa and contained the canonical WCGPC active site. Recombinant Trxh showed the disulfide reduction activity, and exhibited insulin reduction activity. Also, Trxh had higher 5,5'-dithiobis(2-nitrobenzoic acid) reduction activity with Arabidopsis thioredoxin reductase (TR) than with Escherichia coli TR. Specific expression of the Trxh gene was further analyzed at mRNA and protein levels and was found to increase by gamma irradiation upto the absorbed dose of 3kGy, suggesting that Trxh may have potential functions in protection of biomolecules from gamma irradiation. PMID:23830452

Yoon, Minchul; Yang, Ho-Yeon; Lee, Seung-Sik; Kim, Dong-Ho; Kim, Gwang-Hoon; Choi, Jong-il

2013-08-15

266

Ventricular Tachycardia Associated with Radiation-Induced Cardiac Sarcoma  

PubMed Central

Cardiac tumors can lead to distinct electrocardiographic changes and ventricular arrhythmias. Benign and malignant cardiac tumors have been associated with ventricular tachycardia. When possible, benign tumors should be resected when ventricular arrhythmias are intractable. Chemotherapy can shrink malignant tumors and eliminate arrhythmias. We report the case of a 52-year-old woman with breast sarcoma whom we diagnosed with myocardial metastasis after she presented with palpitations. The initial electrocardiogram revealed sinus rhythm with new right bundle branch block and ST-segment elevation in the anterior precordial leads. During telemetry, hemodynamically stable, sustained ventricular tachycardia with right ventricular localization was detected. Images showed a myocardial mass in the right ventricular free wall. Amiodarone suppressed the arrhythmia. To our knowledge, this is the first report of ventricular tachycardia associated with radiation-induced undifferentiated sarcoma. We discuss the distinct electrocardiographic changes and ventricular arrhythmias that can be associated with cardiac tumors, and we review the relevant medical literature. PMID:25593527

Beaty, Elijah H.; Ballany, Wassim; Trohman, Richard G.

2014-01-01

267

Bystander effects in radiation-induced genomic instability  

NASA Technical Reports Server (NTRS)

Exposure of GM10115 hamster-human hybrid cells to X-rays can result in the induction of chromosomal instability in the progeny of surviving cells. This instability manifests as the dynamic production of novel sub-populations of cells with unique cytogenetic rearrangements involving the "marker" human chromosome. We have used the comet assay to investigate whether there was an elevated level of endogenous DNA breaks in chromosomally unstable clones that could provide a source for the chromosomal rearrangements and thus account for the persistent instability observed. Our results indicate no significant difference in comet tail measurement between non-irradiated and radiation-induced chromosomally unstable clones. Using two-color fluorescence in situ hybridization we also investigated whether recombinational events involving the interstitial telomere repeat-like sequences in GM10115 cells were involved at frequencies higher than random processes would otherwise predict. Nine of 11 clones demonstrated a significantly higher than expected involvement of these interstitial telomere repeat-like sequences at the recombination junction between the human and hamster chromosomes. Since elevated levels of endogenous breaks were not detected in unstable clones we propose that epigenetic or bystander effects (BSEs) lead to the activation of recombinational pathways that perpetuate the unstable phenotype. Specifically, we expand upon the hypothesis that radiation induces conditions and/or factors that stimulate the production of reactive oxygen species (ROS). These reactive intermediates then contribute to a chronic pro-oxidant environment that cycles over multiple generations, promoting chromosomal recombination and other phenotypes associated with genomic instability.

Morgan, William F.; Hartmann, Andreas; Limoli, Charles L.; Nagar, Shruti; Ponnaiya, Brian

2002-01-01

268

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

269

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 " lang="en"> <div class="resultNumber element">270</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/22300035"> <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://www.osti.gov/scitech">SciTech Connect</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., E-mail: magda@lanl.gov, E-mail: efu@pku.edu.cn; Fu, E. G., E-mail: magda@lanl.gov, E-mail: efu@pku.edu.cn; Wang, Y. Q.; Martinez, E.; Caro, A. [Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Mook, W. M.; Sheehan, C.; Baldwin, J. K. [Center for Integrated Nanotechnology, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-06-09</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">271</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 " lang="en"> <div class="resultNumber element">272</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=19830060651&hterms=calcite+mineral&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dcalcite%2Bmineral"> <span id="translatedtitle">Heterogeneous shock-<span class="hlt">induced</span> thermal <span class="hlt">radiation</span> in minerals</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 500-channel optical imaging intensifying and spectral digital recording system is used for recording the shock-<span class="hlt">induced</span> <span class="hlt">radiation</span> emitted from 406 to 821 nm from transparent minerals during the time interval that a shock wave propagates through the sample. The initial results obtained for single crystals of gypsum, calcite and halite in the 30 to 40 GPa (300 to 400 kbar) pressure range reveal grey-body emission spectra corresponding to temperatures in the 3000 to 4000 K range and emissivities ranging from 0.003 to 0.02. With gypsum and calcite, distinctive line spectra are superimposed on the thermal <span class="hlt">radiation</span>. The observed color temperatures are greater than the Hugoniot temperature by a factor of 2 to 10; this is calculable on the basis of continuum thermodynamics and equation of state models for the shock states achieved in the three minerals. These observed high temperatures are thought to be real. It is concluded that a large number of closed spaced high temperature shear-band regions are being detected immediately behind the shock front.</p> <div class="credits"> <p class="dwt_author">Kondo, K.-I.; Ahrens, T. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">1983-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">273</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=4259957"> <span id="translatedtitle"><span class="hlt">Radiation-induced</span> sarcomas of the head and neck</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">With improved outcomes associated with radiotherapy, <span class="hlt">radiation-induced</span> sarcomas (RIS) are increasingly seen in long-term survivors of head and neck cancers, with an estimated risk of up to 0.3%. They exhibit no subsite predilection within the head and neck and can arise in any irradiated tissue of mesenchymal origin. Common histologic subtypes of RIS parallel their de novo counterparts and include osteosarcoma, chondrosarcoma, malignant fibrous histiocytoma/sarcoma nitricoxide synthase, and fibrosarcoma. While imaging features of RIS are not pathognomonic, large size, extensive local invasion with bony destruction, marked enhancement within a prior radiotherapy field, and an appropriate latency period are suggestive of a diagnosis of RIS. RIS development may be influenced by factors such as <span class="hlt">radiation</span> dose, age at initial exposure, exposure to chemotherapeutic agents and genetic tendency. Precise pathogenetic mechanisms of RIS are poorly understood and both directly mutagenizing effects of radiotherapy as well as changes in microenvironments are thought to play a role. Management of RIS is challenging, entailing surgery in irradiated tissue and a limited scope for further radiotherapy and chemotherapy. RIS is associated with significantly poorer outcomes than stage-matched sarcomas that arise independent of irradiation and surgical resection with clear margins seems to offer the best chance for cure. PMID:25493233</p> <div class="credits"> <p class="dwt_author">Thiagarajan, Anuradha; Iyer, N Gopalakrishna</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">274</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=3354559"> <span id="translatedtitle">Are Epigenetic Mechanisms Involved in <span class="hlt">Radiation-Induced</span> Bystander Effects?</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">The “non-targeted effects” of ionizing <span class="hlt">radiation</span> including bystander effects and genomic instability are unique in that no classic mutagenic event occurs in the cell showing the effect. In the case of bystander effects, cells which were not in the field affected by the <span class="hlt">radiation</span> show high levels of mutations, chromosome aberrations, and membrane signaling changes leading to what is termed “horizontal transmission” of mutations and information which may be damaging while in the case of genomic instability, generations of cells derived from an irradiated progenitor appear normal but then lethal and non-lethal mutations appear in distant progeny. This is known as “vertical transmission.” In both situations high yields of non-clonal mutations leading to distant occurrence of mutation events both in space and time. This precludes a mutator phenotype or other conventional explanation and appears to indicate a generalized form of stress-<span class="hlt">induced</span> mutagenesis which is well documented in bacteria. This review will discuss the phenomenology of what we term “non-targeted effects,” and will consider to what extent they challenge conventional ideas in genetics and epigenetics. PMID:22629281</p> <div class="credits"> <p class="dwt_author">Mothersill, Carmel; Seymour, Colin</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">275</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=20040089880&hterms=mammary+gland&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3D%2528mammary%2Bgland%2529"> <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://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</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">1996-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">276</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/2013Nanos...5.5539H"> <span id="translatedtitle">Strain-<span class="hlt">induced</span> macroscopic magnetic anisotropy from smectic liquid-<span class="hlt">crystalline</span> elastomer-maghemite nanoparticle hybrid nanocomposites</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">We combine tensile strength analysis and X-ray scattering experiments to establish a detailed understanding of the microstructural coupling between liquid-<span class="hlt">crystalline</span> 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.We combine tensile strength analysis and X-ray scattering experiments to establish a detailed understanding of the microstructural coupling between liquid-<span class="hlt">crystalline</span> 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. Electronic supplementary information (ESI) available: Fig. ESI-1: polarized optical microscopy images, Fig. ESI-2-4: supplementary X-ray data, Fig. ESI-5: FORC diagrams. See DOI: 10.1039/c3nr01016c</p> <div class="credits"> <p class="dwt_author">Haberl, Johannes M.; Sánchez-Ferrer, Antoni; Mihut, Adriana M.; Dietsch, Hervé; Hirt, Ann M.; Mezzenga, Raffaele</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-05-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">277</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/2015ApSS..326..216J"> <span id="translatedtitle">Femtosecond laser-<span class="hlt">induced</span> cross-periodic structures on a <span class="hlt">crystalline</span> silicon surface under low pulse number irradiation</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 cross-patterned surface periodic structure in femtosecond laser processing of <span class="hlt">crystalline</span> silicon was revealed under a relatively low shots (4 < N < 10) with the pulse energy slightly higher than the ablation threshold. The experimental results indicated that the cross-pattern was composed of mutually orthogonal periodic structures (ripples). Ripples with a direction perpendicular to laser polarization (R?) spread in the whole laser-modified region, with the periodicity around 780 nm which was close to the central wavelength of the laser. Other ripples with a direction parallel to laser polarization (R?) were found to be distributed between two of the adjacent ripples R?, with a periodicity about the sub-wavelength of the irradiated laser, 390 nm. The geometrical morphology of two mutually orthogonal ripples under static femtosecond laser irradiation could be continuously rotated as the polarization directions changed, but the periodicity remained almost unchanged. The underlying physical mechanism was revealed by numerical simulations based on the finite element method. It was found that the incubation effect with multiple shots, together with the redistributed electric field after initial ablation, plays a crucial role in the generation of the cross-patterned periodic surface structures.</p> <div class="credits"> <p class="dwt_author">Ji, Xu; Jiang, Lan; Li, Xiaowei; Han, Weina; Liu, Yang; Wang, Andong; Lu, Yongfeng</p> <p class="dwt_publisher"></p> <p class="publishDate">2015-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">278</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/61393814"> <span id="translatedtitle">Are lesions <span class="hlt">induced</span> by ionizing <span class="hlt">radiation</span> direct blocks to DNA chain elongation</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> blocks DNA chain elongation in normal diploid fibroblasts but not in fibroblasts from patients with ataxia-telangiectasia, even though there are no differences in the damage <span class="hlt">induced</span> between the two cell types. This difference suggests that <span class="hlt">radiation-induced</span> lesions in DNA are not themselves blocks to chain elongation in ataxia cells and raises the possibility that in normal cells a</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">1983-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">279</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 " lang="en"> <div class="resultNumber element">280</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.colorado.edu/MCDB/sulab/Wichmann%202006.pdf"> <span id="translatedtitle">Ionizing <span class="hlt">radiation</span> <span class="hlt">induces</span> caspase-dependent but Chk2-and p53-independent cell death</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary"><span class="hlt">radiation</span> (IR) can <span class="hlt">induce</span> apoptosis via p53, which is the most commonly mutated gene in human cancers. Loss after exposure to a LD50 dose. In mutants of Drosophila Chk2 or p53 homologs, apoptosis is severelyIonizing <span class="hlt">radiation</span> <span class="hlt">induces</span> caspase-dependent but Chk2- and p53-independent cell death in Drosophila</p> <div class="credits"> <p class="dwt_author">Su, Tin Tin</p> <p class="dwt_publisher"></p> <p class="publishDate"></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_13");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" 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showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_16");' 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">281</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://cancerres.aacrjournals.org/cgi/reprint/65/15/6734.pdf"> <span id="translatedtitle">Cellular Mechanisms for Low-Dose Ionizing <span class="hlt">Radiation-Induced</span> Perturbation of the Breast Tissue Microenvironment</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</span> exposure is an important form of environmental carcinogen and has been associated with increased risk of breast cancer. Epigenetic events, especially those involving alterations in the breast stromal microenvironment, may play an important role in <span class="hlt">radiation-induced</span> carcinogenesis but remain not well understood. We here show that human mammary stromal fibroblasts respond to protracted low-dose ionizing <span class="hlt">radiation</span> exposures by displaying</p> <div class="credits"> <p class="dwt_author">Kelvin K. C. Tsai; Eric Yao-Yu Chuang; John B. Little</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">282</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/2013RaPC...84..185T"> <span id="translatedtitle">On the mechanisms of the <span class="hlt">radiation-induced</span> degradation of cellulosic substances</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">Much interest has been generated in utilizing ionizing <span class="hlt">radiation</span> for the production of bio-fuels from cellulosic plant materials. It is well known that exposure of cellulose to ionizing <span class="hlt">radiation</span> causes significant breakdown of the polysaccharide. <span class="hlt">Radiation-induced</span> degradation of cellulose may reduce or replace ecologically hazardous chemical steps in addition to reducing the number of processing stages and decreasing energy consumption.</p> <div class="credits"> <p class="dwt_author">Tissot, Chanel; Grdanovska, Slavica; Barkatt, Aaron; Silverman, Joseph; Al-Sheikhly, Mohamad</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">283</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.math.psu.edu/cao/Papers_PDF/QinFeng-5-9-2011.pdf"> <span id="translatedtitle">Pressure-sensitive blackbody point <span class="hlt">radiation</span> <span class="hlt">induced</span> by infrared diode laser irradiation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Pressure-sensitive blackbody point <span class="hlt">radiation</span> <span class="hlt">induced</span> by infrared diode laser irradiation Feng Qin,1 Ultrabroadband <span class="hlt">radiation</span> from Yb2O3 at ambient and low air pressures was investigated under the excitation to environmental air pressure in the way that the integrated <span class="hlt">radiation</span> intensity decreases linearly with increasing</p> <div class="credits"> <p class="dwt_author">Cao, Wenwu</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">284</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://radhome.gsfc.nasa.gov/radhome/papers/tns07_chen.pdf"> <span id="translatedtitle">Mechanisms of Enhanced <span class="hlt">Radiation-Induced</span> Degradation Due to Excess Molecular Hydrogen in Bipolar 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">Bipolar junction test structures packaged in hermetically sealed packages with excess molecular hydrogen (H2) showed enhanced degradation after <span class="hlt">radiation</span> exposure. Using chemical kinetics, we propose a model that quantitatively establishes the relationship between excess H2 and <span class="hlt">radiation-induced</span> interface trap formation. Using environments with different molecular hydrogen concentrations, <span class="hlt">radiation</span> experiments were performed and the experimental data showed excellent agreement with the</p> <div class="credits"> <p class="dwt_author">X. J. Chen; H. J. Barnaby; B. Vermeire; K. Holbert; D. Wright; R. L. Pease; G. Dunham; D.G. Platteter; J. Seiler; S. McClure; P. Adell</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">285</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/2012SMaS...21l5012Y"> <span id="translatedtitle">Coupled effects of director orientations and boundary conditions on light <span class="hlt">induced</span> bending of monodomain nematic liquid <span class="hlt">crystalline</span> polymer plates</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 photo-chromic liquid crystal polymers (LCPs) is a smart material for large light-activated variation or bending to transfer luminous energy into mechanical energy. We study the light <span class="hlt">induced</span> behavior by modeling planar and homeotropic nematic network polymer plates. We effectively illustrate some reported experimental outcomes and theoretically predict some possible bending patterns. This paper constructs an understanding between the bending behaviors and interactions among the alignments, aspect ratios and boundary conditions, etc. Our work provides information on optimizing light <span class="hlt">induced</span> bending in the process of micro-opto-mechanical system (MOMS) design.</p> <div class="credits"> <p class="dwt_author">You, Yue; Xu, Changwei; Ding, Shurong; Huo, Yongzhong</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">286</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/2009APS..SHK.J2001C"> <span id="translatedtitle">Pressure <span class="hlt">induced</span> phase transitions in Vacancy-doped nano-<span class="hlt">crystalline</span> manganites through High-pressure Mössbauer spectroscopy</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">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-<span class="hlt">crystalline</span> 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.</p> <div class="credits"> <p class="dwt_author">Chandra, Usha</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-06-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">287</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/25423999"> <span id="translatedtitle">Single-<span class="hlt">crystalline</span> organic-inorganic layered cobalt hydroxide nanofibers: facile synthesis, characterization, and reversible water-<span class="hlt">induced</span> structural conversion.</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">New pink organic-inorganic layered cobalt hydroxide nanofibers intercalated with benzoate ions [Co(OH)(C6H5COO)·H2O] have been synthesized by using cobalt nitrate and sodium benzoate as reactants in water with no addition of organic solvent or surfactant. The high-purity nanofibers are single-<span class="hlt">crystalline</span> in nature and very uniform in size with a diameter of about 100 nm and variable lengths over a wide range from 200 ?m down to 2 ?m by simply adjusting reactant concentrations. The as-synthesized products are well-characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), fast Fourier transforms (FFT), X-ray diffraction (XRD), energy dispersive X-ray spectra (EDX), X-ray photoelectron spectra (XPS), elemental analysis (EA), Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), and UV-vis diffuse reflectance spectra (UV-vis). Our results demonstrate that the structure consists of octahedral cobalt layers and the benzoate anions, which are arranged in a bilayer due to the ?-? stacking of small aromatics. The carboxylate groups of benzoate anions are coordinated to Co(II) ions in a strong bridging mode, which is the driving force for the anisotropic growth of nanofibers. When NaOH is added during the synthesis, green irregular shaped platelets are obtained, in which the carboxylate groups of benzoate anions are coordinated to the Co(II) ions in a unidentate fashion. Interestingly, the nanofibers exhibit a reversible transformation of the coordination geometry of the Co(II) ions between octahedral and pseudotetrahedral with a concomitant color change between pink and blue, which involves the loss and reuptake of unusual weakly coordinated water molecules without destroying the structure. This work offers a facile, cost-effective, and green strategy to rationally design and synthesize functional nanomaterials for future applications in catalysis, magnetism, gas storage or separation, and sensing technology. PMID:25423999</p> <div class="credits"> <p class="dwt_author">Guo, Xiaodi; Wang, Lianying; Yue, Shuang; Wang, Dongyang; Lu, Yanluo; Song, Yufei; He, Jing</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-12-15</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">288</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=3338537"> <span id="translatedtitle">PAI-1-Dependent Endothelial Cell Death Determines Severity of <span class="hlt">Radiation-Induced</span> Intestinal Injury</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">Normal tissue toxicity still remains a dose-limiting factor in clinical <span class="hlt">radiation</span> therapy. Recently, plasminogen activator inhibitor type 1 (SERPINE1/PAI-1) was reported as an essential mediator of late <span class="hlt">radiation-induced</span> intestinal injury. However, it is not clear whether PAI-1 plays a role in acute <span class="hlt">radiation-induced</span> intestinal damage and we hypothesized that PAI-1 may play a role in the endothelium radiosensitivity. In vivo, in a model of <span class="hlt">radiation</span> enteropathy in PAI-1 ?/? mice, apoptosis of radiosensitive compartments, epithelial and microvascular endothelium was quantified. In vitro, the role of PAI-1 in the <span class="hlt">radiation-induced</span> endothelial cells (ECs) death was investigated. The level of apoptotic ECs is lower in PAI-1 ?/? compared with Wt mice after irradiation. This is associated with a conserved microvascular density and consequently with a better mucosal integrity in PAI-1 ?/? mice. In vitro, irradiation rapidly stimulates PAI-1 expression in ECs and <span class="hlt">radiation</span> sensitivity is increased in ECs that stably overexpress PAI-1, whereas PAI-1 knockdown increases EC survival after irradiation. Moreover, ECs prepared from PAI-1 ?/? mice are more resistant to <span class="hlt">radiation-induced</span> cell death than Wt ECs and this is associated with activation of the Akt pathway. This study demonstrates that PAI-1 plays a key role in <span class="hlt">radiation-induced</span> EC death in the intestine and suggests that this contributes strongly to the progression of <span class="hlt">radiation-induced</span> intestinal injury. PMID:22563394</p> <div class="credits"> <p class="dwt_author">Abderrahmani, Rym; François, Agnes; Buard, Valerie; Tarlet, Georges; Blirando, Karl; Hneino, Mohammad; Vaurijoux, Aurelie; Benderitter, Marc; Sabourin, Jean-Christophe; Milliat, Fabien</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">289</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/25407082"> <span id="translatedtitle">A mechanistic investigation of morphology evolution in P3HT-PCBM films <span class="hlt">induced</span> by liquid <span class="hlt">crystalline</span> molecules under external electric field.</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 morphology of poly(3-hexyl thiophene) and [6,6]-phenyl-C61-butyric acid methyl ester (P3HT-PCBM) bulk heterojunctions (BHJ) could be tuned by the 4-cyano-4'-pentylterphenyl (5CT) liquid <span class="hlt">crystalline</span> molecules under electric field assisted treatment for enhanced solar cell performance. The miscibility and interactions between the components were carefully studied, showing that 5CT could <span class="hlt">induce</span> the crystallization of P3HT to form edge-on structures in ternary blends after electric field assisted treatment as revealed by grazing-incidence wide-angle X-ray diffraction (GIXRD). The PCBM and 5CT are supposed to form the rod-like complexes, and the nanorods could orient to the direction of electric field, accompanied by the homogeneous distribution of nanorods in diameters of about 30 nm at an electric field of 600 V mm(-1). The sizes of PCBM clusters and complexes are dependent on the 5CT doping ratios and intensity of electric field according to grazing-incidence small-angle X-ray scattering (GISAXS) analysis. When the active layers were processed under the atmospheric environment, the power conversion efficiency (PCE) could reach 3.5% at 5CT weight fraction of 6 wt% after treatment by an electric field of 600 V mm(-1), in contrast to the PCE value of 2.4% for a pristine P3HT-PCBM blend. This work provides an attractive strategy for manipulating the nanostructure of BHJ layers and also increases insight into morphology evolution when liquid <span class="hlt">crystalline</span> molecules are incorporated into BHJs. PMID:25407082</p> <div class="credits"> <p class="dwt_author">Zhou, Weihua; Shi, Jiangman; Lv, Lingjian; Chen, Lie; Chen, Yiwang</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">290</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.molbiolcell.org/cgi/reprint/14/8/3292.pdf"> <span id="translatedtitle">Irod\\/Ian5: An Inhibitor of  <span class="hlt">Radiation</span> and Okadaic Acid-<span class="hlt">induced</span> Apoptosis</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">Protein phosphatase-directed toxins such as okadaic acid (OA) are general apoptosis <span class="hlt">inducers</span>. We show that a protein (inhibitor of <span class="hlt">radiation</span>- and OA-<span class="hlt">induced</span> apoptosis, Irod\\/Ian5), belonging to the family of immune-associated nucleotide binding proteins, protected Jurkat T-cells against OA- and -<span class="hlt">radiation-induced</span> apoptosis. Unlike previously described antiapoptotic proteins Irod\\/Ian5 did not protect against anti-Fas, tumor necrosis factor-, staurosporine, UV-light, or a number</p> <div class="credits"> <p class="dwt_author">Tone Sandal; Linda Aumo; Lars Hedin; Bjørn T. Gjertsen; Stein O. Doskeland</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">291</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">292</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/18975154"> <span id="translatedtitle">Pretreatment of low dose <span class="hlt">radiation</span> reduces <span class="hlt">radiation-induced</span> apoptosis in mouse lymphoma (EL4) 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">Induction of an adaptive response to ionizing <span class="hlt">radiation</span> in mouse lymphoma (EL4) cells was studied by using cell survival fraction and apoptotic nucleosomal DNA fragmentation as biological end points. Cells in early log phase were pre-exposed to low dose of gamma-rays (0.01 Gy) 4 or 20 hrs prior to high dose gamma-ray (4, 8 and 12 Gy for cell survival fraction analysis; 8 Gy for DNA fragmentation analysis) irradiation. Then cell survival fractions and the extent of DNA fragmentation were measured. Significant adaptive response, increase in cell survival fraction and decrease in the extent of DNA fragmentation were <span class="hlt">induced</span> when low and high dose gamma-ray irradiation time interval was 4 hr. Addition of protein or RNA synthesis inhibitor, cycloheximide or 5,6-dichloro-1-beta-d-ribofuranosylbenzimidazole (DRFB), respectively during adaptation period, the period from low dose gamma-ray irradiation to high dose gamma-ray irradiation, was able to inhibit the induction of adaptive response, which is the reduction of the extent DNA fragmentation in irradiated EL4 cells. These data suggest that the induction of adaptive response to ionizing <span class="hlt">radiation</span> in EL4 cells required both protein and RNA synthesis. PMID:18975154</p> <div class="credits"> <p class="dwt_author">Kim, J H; Hyun, S J; Yoon, M Y; Ji, Y H; Cho, C K; Yoo, S Y</p> <p class="dwt_publisher"></p> <p class="publishDate">1997-06-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">293</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">294</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/6145913"> <span id="translatedtitle"><span class="hlt">Radiation</span> damage of gallium arsenide <span class="hlt">induced</span> by reactive ion etching</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"><span class="hlt">Radiation</span> damage <span class="hlt">induced</span> in the surface of gallium arsenide (GaAs) by reactive ion etching (RIE)is studied using physical and electrical analyses. The number of displaced Ga and As atoms observed by Rutherford backscattering spectrometry aligned spectra is 7.8 x 10/sup 15/ cm/sup -2/ and 1.3 x 10/sup 16/ cm/sup -2/ at rf power of 300 W (0.47 W/cm/sup 2/) and 500 W (0.78 W/cm/sup 2/), respectively. The barrier height of the Schottky electrode formed on the undamaged layer is 0.745 V. The height decreases with increasing rf power and reaches 0.47 V at 0.78 W/cm/sup 2/. Carrier concentration at the surface of the GaAs channel layer decreases with increasing rf power. The damage can be reduced by annealing at 400 /sup 0/C for 30 min. For instance, the barrier height at 300 W increases from 0.47 to 0.70 V, and the carrier concentration increases from 7.0 x 10/sup 16/ to 1.3 x 10/sup 17/ cm/sup -3/. However, the carrier concentration cannot recover to the same level as that of an undamaged layer with annealing at 400 /sup 0/C. The temperature conventionally employed in GaAs electrode annealing process.</p> <div class="credits"> <p class="dwt_author">Hara, T.; Suzuki, H.; Suga, A.; Terada, T.; Toyoda, N.</p> <p class="dwt_publisher"></p> <p class="publishDate">1987-11-15</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">295</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/1987JAP....62.4109H"> <span id="translatedtitle"><span class="hlt">Radiation</span> damage of gallium arsenide <span class="hlt">induced</span> by reactive ion etching</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</span> damage <span class="hlt">induced</span> in the surface of gallium arsenide (GaAs) by reactive ion etching (RIE)is studied using physical and electrical analyses. The number of displaced Ga and As atoms observed by Rutherford backscattering spectrometry aligned spectra is 7.8×1015 cm-2 and 1.3×1016 cm-2 at rf power of 300 W (0.47 W/cm2) and 500 W (0.78 W/cm2), respectively. The barrier height of the Schottky electrode formed on the undamaged layer is 0.745 V. The height decreases with increasing rf power and reaches 0.47 V at 0.78 W/cm2. Carrier concentration at the surface of the GaAs channel layer decreases with increasing rf power. The damage can be reduced by annealing at 400 °C for 30 min. For instance, the barrier height at 300 W increases from 0.47 to 0.70 V, and the carrier concentration increases from 7.0×1016 to 1.3×1017 cm-3. However, the carrier concentration cannot recover to the same level as that of an undamaged layer with annealing at 400 °C. The temperature conventionally employed in GaAs electrode annealing process.</p> <div class="credits"> <p class="dwt_author">Hara, Tohru; Suzuki, Hidenori; Suga, Akio; Terada, Toshiyuki; Toyoda, Nobuyuki</p> <p class="dwt_publisher"></p> <p class="publishDate">1987-11-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">296</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">297</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=thick+dielectric+SiO2+electrical+breakdown&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dthick%2Bdielectric%2BSiO2%2Belectrical%2Bbreakdown"> <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">298</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. PMID:24558369</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">299</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/2008cosp...37..284B"> <span id="translatedtitle">Enhanced homologous recombination is <span class="hlt">induced</span> by alpha-particle <span class="hlt">radiation</span> in somatic cells of Arabidopsis thaliana</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">Almost 9 percent of cosmic rays which strike the earth's atmosphere are alpha particles. As one of the ionizing <span class="hlt">radiations</span> (IR), its biological effects have been widely studied. However, the plant genomic instability <span class="hlt">induced</span> by alpha-particle <span class="hlt">radiation</span> was not largely known. In this research, the Arabidopsis thaliana transgenic for GUS recombination substrate was used to evaluate the genomic instability <span class="hlt">induced</span> by alpha-particle <span class="hlt">radiation</span> (3.3MeV). The pronounced effects of systemic exposure to alpha-particle <span class="hlt">radiation</span> on the somatic homologous recombination frequency (HRF) were found at different doses. The 10Gy dose of <span class="hlt">radiation</span> <span class="hlt">induced</span> the maximal HRF which was 1.9-fold higher than the control. The local <span class="hlt">radiation</span> of alpha-particle (10Gy) on root also resulted in a 2.5-fold increase of somatic HRF in non-<span class="hlt">radiated</span> aerial plant, indicating that the signal(s) of genomic instability was transferred to non-<span class="hlt">radiated</span> parts and initiated their genomic instability. Concurrent treatment of seedlings of Arabidopsis thaliana with alpha-particle and DMSO(ROS scavenger) both in systemic and local <span class="hlt">radiation</span> signifi- cantly suppressed the somatic HR, indicating that the free radicals produced by alpha-particle <span class="hlt">radiation</span> took part in the production of signal of genomic instability rather than the signal transfer. Key words: alpha-particle <span class="hlt">radiation</span>, somatic homologous recombination, genomic instability</p> <div class="credits"> <p class="dwt_author">Bian, Po; Liu, Ping; Wu, Yuejin</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">300</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=3435866"> <span id="translatedtitle">Spinal Cord Glioblastoma <span class="hlt">Induced</span> by <span class="hlt">Radiation</span> Therapy of Nasopharyngeal Rhabdomyosarcoma with MRI Findings: Case Report</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"><span class="hlt">Radiation-induced</span> spinal cord gliomas are extremely rare. Since the first case was reported in 1980, only six additional cases have been reported.; The <span class="hlt">radiation-induced</span> gliomas were related to the treatment of Hodgkin's lymphoma, thyroid cancer, and medullomyoblastoma, and to multiple chest fluoroscopic examinations in pulmonary tuberculosis patient. We report a case of <span class="hlt">radiation-induced</span> spinal cord glioblastoma developed in a 17-year-old girl after a 13-year latency period following radiotherapy for nasopharyngeal rhabdomyosarcoma. MRI findings of our case are described. PMID:22977336</p> <div class="credits"> <p class="dwt_author">Ahn, Se Jin</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</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_14");' 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 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<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 style="font-weight: bold;">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 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_17");' 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">301</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/10115362"> <span id="translatedtitle">Transient <span class="hlt">radiation-induced</span> absorption in the materials for a GSGG laser</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">Materials used in the optical elements of a 1,061 m GSGG (gadolinium scandium gallium garnet) laser have been tested for transient <span class="hlt">radiation-induced</span> absorption. The transient <span class="hlt">radiation-induced</span> absorption in KK1, Schott S7005 and S7010, and M382 glasses have been determined for discrete wavelengths in the range 440--750 nm. Also, the transient <span class="hlt">radiation-induced</span> absorption in {open_quotes}pure{close_quotes} and MgO doped LiNbO{sub 3} has been measured at 1,061 nm. Mathematical expressions composed of exponentials are fitted to the data.</p> <div class="credits"> <p class="dwt_author">Brannon, P.J.</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-11-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">302</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/2002PhDT.......132P"> <span id="translatedtitle"><span class="hlt">Radiation-induced</span> changes affecting polyester based polyurethane binder</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 application of thermoplastic polyurethane elastomers as binders in the high energy explosives particularly when used in weapons presents a significantly complex and challenging problem due to the impact of the aging of this polymer on the useful service life of the explosive. In this work, the effects of <span class="hlt">radiation</span> on the aging of the polyester based polyurethane were investigated using both electron beam and gamma irradiation at various dose rates in the presence and absence of oxygen. It was found by means of GPC that, in the presence and absence of oxygen, the poly (ester urethane) primarily undergoes cross-linking, by means of a carbon-centered secondary alkyl radical. It was also concluded that the polymer partially undergoes scission of the backbone of the main chain at C-O, N-C, and C-C bonds. Substantial changes in the conditions of irradiation and in dose levels did not affect the cross-linking and scission yields. Experiments were also performed with EPR spectroscopy for the purpose of identifying the initial carbon-centered free radicals and for studying the decay mechanisms of these radicals. It was found that the carbon-centered radical which is produced via C-C scission (primary alkyl radical) is rapidly converted to a long-lived allylic species at higher temperatures; more than 80% radicals are converted to allyl species in 2.5 hours. In the presence of oxygen, the allyl radical undergoes a fast reaction to produce a peroxyl radical; this radical decays with a 1.7 hour half-life by pseudo first-order kinetics to negligible levels in 13 hours. FTIR measurements were conducted to identify the <span class="hlt">radiation-induced</span> changes to the functional groups in the polyester polyurethane. These measurements show an increase in carbonyl, amine and carboxylic groups as a result of reaction of H atoms with R-C-O·, ·NH-R and R-COO·. The FTIR results also demonstrate the production of the unsaturation resulting from hydrogen atom transfer during intrachain conversion of the primary alkyl radical to the allyl species, prompt trans-vinylene production in tetramethylene units, and hydrogen atom abstraction by alkyl radicals on neighboring chains. The production of unsaturation is substantiated by the EPR studies. Finally, a free radical mechanism is proposed for the production of cross-linking in polyester polyurethane.</p> <div class="credits"> <p class="dwt_author">Pierpoint, Sujita Basi</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">303</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 " lang="en"> <div class="resultNumber element">304</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=Gene&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DGene"> <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 odd" lang="en"> <div class="resultNumber element">305</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/22283357"> <span id="translatedtitle">A Nonhuman Primate Model of Human <span class="hlt">Radiation-Induced</span> Venocclusive Liver Disease and Hepatocyte Injury</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">Background: Human liver has an unusual sensitivity to <span class="hlt">radiation</span> that limits its use in cancer therapy or in preconditioning for hepatocyte transplantation. Because the characteristic veno-occlusive lesions of <span class="hlt">radiation-induced</span> liver disease do not occur in rodents, there has been no experimental model to investigate the limits of safe <span class="hlt">radiation</span> therapy or explore the pathogenesis of hepatic veno-occlusive disease. Methods and Materials: We performed a dose-escalation study in a primate, the cynomolgus monkey, using hypofractionated stereotactic body radiotherapy in 13 animals. Results: At doses ?40 Gy, animals developed a systemic syndrome resembling human <span class="hlt">radiation-induced</span> liver disease, consisting of decreased albumin, elevated alkaline phosphatase, loss of appetite, ascites, and normal bilirubin. Higher <span class="hlt">radiation</span> doses were lethal, causing severe disease that required euthanasia approximately 10 weeks after <span class="hlt">radiation</span>. Even at lower doses in which <span class="hlt">radiation-induced</span> liver disease was mild or nonexistent, latent and significant injury to hepatocytes was demonstrated by asialoglycoprotein-mediated functional imaging. These monkeys developed hepatic failure with encephalopathy when they received parenteral nutrition containing high concentrations of glucose. Histologically, livers showed central obstruction via an unusual intimal swelling that progressed to central fibrosis. Conclusions: The cynomolgus monkey, as the first animal model of human veno-occlusive <span class="hlt">radiation-induced</span> liver disease, provides a resource for characterizing the early changes and pathogenesis of venocclusion, for establishing nonlethal therapeutic dosages, and for examining experimental therapies to minimize <span class="hlt">radiation</span> injury.</p> <div class="credits"> <p class="dwt_author">Yannam, Govardhana Rao [Department of Surgery, University of Nebraska Medical Center, Omaha, Nebraska (United States); Han, Bing [Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania (United States); Department of Hepatobiliary Surgery, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi (China); Setoyama, Kentaro [Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania (United States); Yamamoto, Toshiyuki [Department of Surgery, University of Nebraska Medical Center, Omaha, Nebraska (United States); Ito, Ryotaro; Brooks, Jenna M. [Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania (United States); Guzman-Lepe, Jorge [Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania (United States); Department of Pathology, Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania (United States); Galambos, Csaba [Department of Pathology, Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania (United States); Fong, Jason V. [Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania (United States); Deutsch, Melvin; Quader, Mubina A. [Department of Radiation Oncology, Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania (United States); Yamanouchi, Kosho [Department of Radiation Oncology, Albert Einstein College of Medicine, Bronx, New York (United States); Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, New York (United States); Kabarriti, Rafi; Mehta, Keyur [Department of Radiation Oncology, Albert Einstein College of Medicine, Bronx, New York (United States); Soto-Gutierrez, Alejandro [Department of Pathology, Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania (United States); McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania (United States); and others</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-02-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">306</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 odd" lang="en"> <div class="resultNumber element">307</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/19585028"> <span id="translatedtitle">Glycine and L-serine <span class="hlt">crystalline</span> perhydrates.</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 report the first <span class="hlt">crystalline</span> amino acid perhydrates, show <span class="hlt">induced</span> chirality of hydrogen peroxide in L-serine perhydrate, and demonstrate that the glycine perhydrate contains 40.47 wt% hydrogen peroxide. PMID:19585028</p> <div class="credits"> <p class="dwt_author">Churakov, Andrei V; Prikhodchenko, Petr V; Howard, Judith A K; Lev, Ovadia</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-07-28</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">308</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 odd" lang="en"> <div class="resultNumber element">309</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/25483171"> <span id="translatedtitle">Molecular responses of <span class="hlt">radiation-induced</span> liver damage in rats.</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 aim of the present study was to investigate the molecular responses involved in <span class="hlt">radiation?induced</span> liver damage (RILD). Sprague?Dawley rats (6?weeks?old) were irradiated once at a dose of 20 Gy to the right upper quadrant of the abdomen. The rats were then sacrificed 3 days and 1, 2, 4, 8 and 12 weeks after irradiation and rats, which were not exposed to irradiation were used as controls. Weight measurements and blood was obtained from the rats and liver tissues were collected for histological and apoptotic analysis. Immunohistochemistry, reverse transcription quantitative polymerase chain reaction (RT?qPCR) and western blot analysis were performed to measure the expression levels of mRNAs and proteins, respectively. The serum levels of alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase were increased significantly in the RILD rats. Histological investigation revealed the proliferation of collagen and the formation of fibrotic tissue 12 weeks after irradiation. Apoptotic cells were observed predominantly 2 and 4 weeks after irradiation. The immunohistochemistry, RT?qPCR and western blot analysis all revealed the same pattern of changes in the expression levels of the molecules assessed. The expression levels of transforming growth factor??1 (TGF??1), nuclear factor (NF)??B65, mothers against decapentaplegic homolog 3 (Smad3) and Smad7 and connective tissue growth factor were increased during the recovery period following irradiation up to 12 weeks. The expression levels of tumor necrosis factor??, Smad7 and Smad4 were only increased during the early phase (first 4 weeks) of recovery following irradiation. In the RILD rat model, the molecular responses indicated that the TGF??1/Smads and NF??B65 signaling pathways are involved in the mechanism of RILD recovery. PMID:25483171</p> <div class="credits"> <p class="dwt_author">Cheng, Wei; Xiao, Lei; Ainiwaer, Aimudula; Wang, Yunlian; Wu, Ge; Mao, Rui; Yang, Ying; Bao, Yongxing</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">310</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/2014JCrGr.405..131T"> <span id="translatedtitle">Defect formation <span class="hlt">induced</span> by seed-joints during directional solidification of quasi-mono-<span class="hlt">crystalline</span> silicon ingots</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">In this work, the growth behavior inside and above seed gaps during directional solidification of monocrystalline lab-scale silicon ingots was investigated. It will be shown that the silicon melt fills the gaps rapidly and monocrystalline growth starts in most cases at the seed side walls toward the gap center. During this process, dislocations were <span class="hlt">induced</span> at the seed edges and in the gap center by the thermal shock caused by the hot melt and the coalescence of the two growth interfaces, respectively. The dislocations originating from the gap are propagating more or less parallel to the growth axis toward the top of the crystal. These dislocation bundles fan out in dependence of the growth height and axial seed orientation, respectively. It was found that <1 0 0> is the most suitable growth direction in comparison to <1 1 1> and <1 1 0> to avoid defect clusters above the seed gaps which is probably due to the orientation of the preferential glide systems.</p> <div class="credits"> <p class="dwt_author">Trempa, M.; Reimann, C.; Friedrich, J.; Müller, G.; Krause, A.; Sylla, L.; Richter, T.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-11-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">311</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/2015NIMPB.343..167M"> <span id="translatedtitle">Ion beam <span class="hlt">induced</span> luminescence (IBIL) system for imaging of <span class="hlt">radiation</span> <span class="hlt">induced</span> changes in materials</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 progress of construction on the new IBIL (ion beam <span class="hlt">induced</span> luminescence) spectrometer installed at the ion microprobe facility of the Ru?er Boškovi? Institute (RBI) is reported. The IBIL system can be used with beams from either 6.0 MV Tandem Van de Graaff or 1.0 MV Tandetron accelerators. Components of the new apparatus and current experimental set-up are described in detail. Measurements with the new IBIL system were performed using a 2 MeV proton microbeam on three sets of samples. This paper gives a summary of the IBIL arrangement capabilities for various problems, emphasising the potential of this technique for <span class="hlt">radiation</span> damage studies. Due to the relatively good sensitivity of the IBIL spectrometer, integration into the conventional ion beam analysis (IBA) microbeam setup is shown to be possible.</p> <div class="credits"> <p class="dwt_author">Markovi?, N.; Siketi?, Z.; Cosic, D.; Jung, H. K.; Lee, N. H.; Han, W.-T.; Jakši?, M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2015-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">312</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/22275829"> <span id="translatedtitle">Gamma <span class="hlt">radiation</span> <span class="hlt">induced</span> effects in floppy and rigid Ge-containing chalcogenide thin films</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">We explore the <span class="hlt">radiation</span> <span class="hlt">induced</span> effects in thin films from the Ge-Se to Ge-Te systems accompanied with silver <span class="hlt">radiation</span> <span class="hlt">induced</span> diffusion within these films, emphasizing two distinctive compositional representatives from both systems containing a high concentration of chalcogen or high concentration of Ge. The studies are conducted on blanket chalcogenide films or on device structures containing also a silver source. Data about the electrical conductivity as a function of the <span class="hlt">radiation</span> dose were collected and discussed based on material characterization analysis. Raman Spectroscopy, X-ray Diffraction Spectroscopy, and Energy Dispersive X-ray Spectroscopy provided us with data about the structure, structural changes occurring as a result of <span class="hlt">radiation</span>, molecular formations after Ag diffusion into the chalcogenide films, Ag lateral diffusion as a function of <span class="hlt">radiation</span> and the level of oxidation of the studied films. Analysis of the electrical testing suggests application possibilities of the studied devices for <span class="hlt">radiation</span> sensing for various conditions.</p> <div class="credits"> <p class="dwt_author">Ailavajhala, Mahesh S.; Mitkova, Maria [Department of Electrical Engineering, Boise State University, 1910 University Dr. Boise, Idaho 83725-2075 (United States); Gonzalez-Velo, Yago; Barnaby, Hugh; Kozicki, Michael N.; Holbert, Keith [School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, Arizona 85287-9309 (United States); Poweleit, Christian [Department of Physics, Arizona State University, Tempe, Arizona 85287-1504 (United States); Butt, Darryl P. [Department of Material Science and Engineering, Boise State University, 1910 University Dr. Boise, Idaho 83725-2090 (United States)</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-28</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">313</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/2806435"> <span id="translatedtitle">Calpain activation is upstream of caspases in <span class="hlt">radiation-induced</span> apoptosis</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 molecular events involved in apoptosis <span class="hlt">induced</span> by ionizing <span class="hlt">radiation</span> remain unresolved. In this paper we show that the cleavage of fodrin to a 150 kDa fragment is an early proteolytic event in <span class="hlt">radiation-induced</span> apoptosis in the Burkitts' Lymphoma cell line BL30A and requires 100 ?M zVAD-fmk for inhibition. Caspases-1, -3, -6 and -7 were shown to cleave fodrin to</p> <div class="credits"> <p class="dwt_author">Nigel J Waterhouse; Debra M Finucane; Douglas R Green; John S Elce; Sharad Kumar; Emad S Alnemri; Gerald Litwack; KumKum Khanna; Martin F Lavin; Dianne J Watters</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">314</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/28897241"> <span id="translatedtitle">Androgens <span class="hlt">induce</span> oxidative stress and <span class="hlt">radiation</span> resistance in prostate cancer cells though NADPH oxidase</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">Androgen deprivation therapy (ADT) facilitates the response of prostate cancer (PC) to <span class="hlt">radiation</span>. Androgens have been shown to <span class="hlt">induce</span> elevated basal levels of reactive oxygen species (ROS) in PC, leading to adaptation to <span class="hlt">radiation-induced</span> cytotoxic oxidative stress. Here, we show that androgens increase the expression of p22phox and gp91phox subunits of NADPH oxidase (NOX) and ROS production by NOX2 and</p> <div class="credits"> <p class="dwt_author">J P Lu; L Monardo; I Bryskin; Z F Hou; J Trachtenberg; B C Wilson; J H Pinthus</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">315</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.mne.psu.edu/motta/Publications/1998_Weber_JMR.pdf"> <span id="translatedtitle">http://journals.cambridge.org Downloaded: 06 Aug 2012 IP address: 130.203.205.122 <span class="hlt">Radiation</span> effects in <span class="hlt">crystalline</span> ceramics for the immobilization</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">in <span class="hlt">crystalline</span> ceramics for the immobilization of high-level nuclear waste and plutonium W. J. Weber Pacific ceramics that may be used for the immobilization of high-level nuclear waste and plutonium. The current ceramics for the immobilization of high-level nuclear waste TABLE OF CONTENTS I. INTRODUCTION 1435 II</p> <div class="credits"> <p class="dwt_author">Motta, Arthur T.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">316</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/53060618"> <span id="translatedtitle">Effects of <span class="hlt">radiation-induced</span> carbon contamination on the printing performance of extreme ultraviolet masks</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">This dissertation investigates one of the remaining issues for extreme ultraviolet (EUV) lithography, the effects of <span class="hlt">radiation</span> <span class="hlt">induced</span> carbon contamination on the printing performance of patterned EUV masks. The impact of carbon contamination on EUV masks is significant due to the throughput loss and potential effects on imaging performance, and occurs when multilayer surfaces are exposed to EUV <span class="hlt">radiation</span> with</p> <div class="credits"> <p class="dwt_author">Yu-Jen Fan</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">317</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/29243074"> <span id="translatedtitle">Apoptosis in mesangial cells <span class="hlt">induced</span> by ionizing <span class="hlt">radiation</span> and cytotoxic drugs</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">Apoptosis in mesangial cells <span class="hlt">induced</span> by ionizing <span class="hlt">radiation</span> and cytotoxic drugs. Mesangial proliferation contributes to the pathogenesis of many forms of glomerulonephritis. To evaluate the role of apoptosis on the pharmacologic effects of cytotoxic drugs and ionizing <span class="hlt">radiation</span>, we studied their effects on cultured rat mesangial cells (MC), whose apoptotic response to these drugs is unknown. Mesangial cells were cultured</p> <div class="credits"> <p class="dwt_author">Dae Ryong Cha; Stella M Feld; Cynthia Nast; Janine LaPage; Sharon G Adler</p> <p class="dwt_publisher"></p> <p class="publishDate">1996-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">318</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/7136593"> <span id="translatedtitle"><span class="hlt">Radiation-induced</span> meningioma after treatment for pituitary adenoma: Case report and literature review</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"><span class="hlt">Radiation-induced</span> meningiomas are becoming increasingly well-recognized. We report a case of a 35-year-old man who developed a suprasellar meningioma 9 years after receiving a <span class="hlt">radiation</span> dose of 4480 cGy for a pituitary adenoma. The literature is also reviewed. 10 references.</p> <div class="credits"> <p class="dwt_author">Partington, M.D.; Davis, D.H. (Mayo Clinic, Rochester, MN (USA))</p> <p class="dwt_publisher"></p> <p class="publishDate">1990-02-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">319</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://hal.archives-ouvertes.fr/docs/00/85/55/58/PDF/Bouchet-2013_Synchrotron_microbeam_AA.pdf"> <span id="translatedtitle">Synchrotron Microbeam <span class="hlt">Radiation</span> Therapy <span class="hlt">induces</span> hypoxia in intracerebral gliosarcoma but not in the normal brain</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Synchrotron Microbeam <span class="hlt">Radiation</span> Therapy <span class="hlt">induces</span> hypoxia in intracerebral gliosarcoma University, 85748 Garching, Germany Key words: Synchrotron Microbeam <span class="hlt">Radiation</span> Therapy - Brain Tumors;108(1):143-8" DOI : 10.1016/j.radonc.2013.05.013 #12;Bouchet et al. 2013 2 Abstract Purpose Synchrotron microbeam</p> <div class="credits"> <p class="dwt_author">Paris-Sud XI, Université de</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">320</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/28061392"> <span id="translatedtitle">Homeopathic treatment of <span class="hlt">radiation-induced</span> itching in breast cancer patients. A prospective observational study</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">Following surgery for carcinoma of the breast, patients receive local radiotherapy. This can cause itching, which may be severe, in the <span class="hlt">radiation</span> field. The affected skin usually is dry, rough and red. Twenty-five patients were treated homeopathically for <span class="hlt">radiation-induced</span> itching. Fourteen patients developed itching during their course of postoperative <span class="hlt">radiation</span> at 27 days median (range: 14–40). Eleven patients experienced itching</p> <div class="credits"> <p class="dwt_author">O Schlappack</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</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_15");' 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 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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">321</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/19142643"> <span id="translatedtitle">MRI of <span class="hlt">radiation-induced</span> tumors of the head and neck in post-<span class="hlt">radiation</span> nasopharyngeal carcinoma.</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 aim of this study was to document the sites and MRI features of <span class="hlt">radiation-induced</span> tumors (RITs) in the head and neck following treatment for nasopharyngeal carcinoma (NPC). The MRI examinations and clinical records of 20 patients with 21 RITs were reviewed retrospectively. RITs developed 3-30 years after radiotherapy and included eleven squamous cell carcinomas, six sarcomas, two neuroendocrine carcinomas, one mucoepidermoid carcinoma and one meningioma. RITs arose in the maxillary region (9), oro/hypopharynx and oral cavity (5), external auditory canal (4), nasopharynx and sphenoid sinus (2) and brain (1). <span class="hlt">Radiation-induced</span> carcinoma and sarcoma had MRI features that were useful to distinguish them from recurrent NPC. To improve early detection of RITs, the check areas on an MRI of a patient with previous NPC treated by <span class="hlt">radiation</span> should always include the maxillary region, tongue, and external auditory canal/temporal bone. PMID:19142643</p> <div class="credits"> <p class="dwt_author">Abrigo, Jill M; King, Ann D; Leung, Sing Fai; Vlantis, Alexander C; Wong, Jeffrey K T; Tong, Michael C F; Tse, Gary M K; Ahuja, Anil T</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">322</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/2014cosp...40E3788Z"> <span id="translatedtitle">Epigenetic Analysis of Heavy-ion <span class="hlt">Radiation</span> <span class="hlt">Induced</span> Bystander Effects in Mice</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">Abstract: <span class="hlt">Radiation-induced</span> bystander effect was defined as the induction of damage in neighboring non-hit cells by signals released from directly-irradiated cells. Recently, low dose of high LET <span class="hlt">radiation</span> <span class="hlt">induced</span> bystander effects in vivo have been reported more and more. It has been indicated that <span class="hlt">radiation</span> <span class="hlt">induced</span> bystander effect was localized not only in bystander tissues but also in distant organs. Genomic, epigenetic and proteomics plays significant roles in regulating heavy-ion <span class="hlt">radiation</span> stress responses in mice. To identify the molecular mechanism that underlies bystander effects of heavy-ion <span class="hlt">radiation</span>, the male Balb/c and C57BL mice were exposed head-only to 40, 200, 2000mGy dose of (12) C heavy-ion <span class="hlt">radiation</span>, while the rest of the animal body was shielded. Directly <span class="hlt">radiation</span> organ ear and the distant organ liver were detected on 1h, 6h, 12h and 24h after <span class="hlt">radiation</span>, respectively. Methylation-sensitive amplification polymorphism (MSAP) was used to monitor the level of polymorphic genomic DNA methylation changed with dose and time effects. The results show that heavy-ion irradiated mouse head could <span class="hlt">induce</span> genomic DNA methylation changes significantly in both the directly <span class="hlt">radiation</span> organ ear and the distant organ liver. The percent of DNA methylation changes were time-dependent and tissue-specific. Demethylation polymorphism rate was highest separately at 1 h in 200 mGy and 6 h in 2000 mGy after irradiation. The global DNA methylation changes tended to occur in the CG sites. The results illustrated that genomic methylation changes of heavy ion <span class="hlt">radiation-induced</span> bystander effect in liver could be obvious 1 h after <span class="hlt">radiation</span> and achieved the maximum at 6 h, while the changes could recover gradually at 12 h. The results suggest that mice head exposed to heavy-ion <span class="hlt">radiation</span> can <span class="hlt">induce</span> damage and methylation pattern changed in both directly <span class="hlt">radiation</span> organ ear and distant organ liver. Moreover, our findings are important to understand the molecular mechanism of <span class="hlt">radiation</span> <span class="hlt">induced</span> bystander effects in vivo.</p> <div class="credits"> <p class="dwt_author">Zhang, Meng; Sun, Yeqing; Cui, Changna; Xue, Bei</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">323</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=4194292"> <span id="translatedtitle">Mechanisms of <span class="hlt">radiation-induced</span> normal tissue toxicity and implications for future clinical trials</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">To summarize current knowledge regarding mechanisms of <span class="hlt">radiation-induced</span> normal tissue injury and medical countermeasures available to reduce its severity. Advances in <span class="hlt">radiation</span> delivery using megavoltage and intensity-modulated <span class="hlt">radiation</span> therapy have permitted delivery of higher doses of <span class="hlt">radiation</span> to well-defined tumor target tissues. Injury to critical normal tissues and organs, however, poses substantial risks in the curative treatment of cancers, especially when <span class="hlt">radiation</span> is administered in combination with chemotherapy. The principal pathogenesis is initiated by depletion of tissue stem cells and progenitor cells and damage to vascular endothelial microvessels. Emerging concepts of <span class="hlt">radiation-induced</span> normal tissue toxicity suggest that the recovery and repopulation of stromal stem cells remain chronically impaired by long-lived free radicals, reactive oxygen species, and pro-inflammatory cytokines/chemokines resulting in progressive damage after <span class="hlt">radiation</span> exposure. Better understanding the mechanisms mediating interactions among excessive generation of reactive oxygen species, production of pro-inflammatory cytokines and activated macrophages, and role of bone marrow-derived progenitor and stem cells may provide novel insight on the pathogenesis of <span class="hlt">radiation-induced</span> injury of tissues. Further understanding the molecular signaling pathways of cytokines and chemokines would reveal novel targets for protecting or mitigating <span class="hlt">radiation</span> injury of tissues and organs. PMID:25324981</p> <div class="credits"> <p class="dwt_author">Jenrow, Kenneth A.; Brown, Stephen L.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">324</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=20090014108&hterms=rate+Exchange&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Drate%2BExchange"> <span id="translatedtitle">M-BAND Study of <span class="hlt">Radiation-Induced</span> Chromosome Aberrations in Human Epithelial Cells: <span class="hlt">Radiation</span> Quality and Dose Rate Effects</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">The advantage of the multicolor banding in situ hybridization (mBAND) technique is its ability to identify both inter- (translocation to unpainted chromosomes) and intra- (inversions and deletions within a single painted chromosome) chromosome aberrations simultaneously. To study the detailed rearrangement of low- and high-LET <span class="hlt">radiation</span> <span class="hlt">induced</span> chromosome aberrations in human epithelial cells (CH184B5F5/M10) in vitro, we performed a series of experiments with Cs-137 gamma rays of both low and high dose rates, neutrons of low dose rate and 600 MeV/u Fe ions of high dose rate, with chromosome 3 painted with multi-binding colors. We also compared the chromosome aberrations in both 2- and 3-dimensional cell cultures. Results of these experiments revealed the highest chromosome aberration frequencies after low dose rate neutron exposures. However, detailed analysis of the <span class="hlt">radiation</span> <span class="hlt">induced</span> inversions revealed that all three <span class="hlt">radiation</span> types <span class="hlt">induced</span> a low incidence of simple inversions. Most of the inversions in gamma-ray irradiated samples were accompanied by other types of intra-chromosomal aberrations but few inversions were accompanied by inter-chromosomal aberrations. In contrast, neutrons and Fe ions <span class="hlt">induced</span> a significant fraction of inversions that involved complex rearrangements of both inter- and intrachromosomal exchanges. The location of the breaks involved in chromosome exchanges was analyzed along the painted chromosome. The breakpoint distribution was found to be randomly localized on chromosome 3 after neutron or Fe ion exposure, whereas non-random distribution with clustering breakpoints was observed after -ray exposure. Our comparison of chromosome aberration yields between 2- and 3-dimensional cell cultures indicated a significant difference for gamma exposures, but not for Fe ion exposures. These experimental results indicated that the track structure of the <span class="hlt">radiation</span> and the cellular/chromosome structure can both affect <span class="hlt">radiation-induced</span> chromosome aberrations.</p> <div class="credits"> <p class="dwt_author">Hada, Megumi; Cucinotta, Francis; Wu, Honglu</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">325</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/2012PhDT.......117F"> <span id="translatedtitle"><span class="hlt">Radiation</span> <span class="hlt">Induced</span> Segregation in High Chromium Ferritic/Martensitic Steels</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">High Cr ferritic/martensitic (F/M) steels including nano-featured oxide dispersion strengthened steels (NF-ODS) are a candidate material class for advanced fission and fusion nuclear reactor designs. F/M steels have excellent high temperature strength, low swelling rates and the recent developments in NF-ODS steels has improved their high temperature creep performance. A concern for F/M steels is their <span class="hlt">radiation</span> <span class="hlt">induced</span> segregation (RIS) response while in-service. RIS occurs when atomic fluxes preferentially couple to point defect fluxes to defect sinks such as grain boundaries (GBs). For F/M steels no conclusive trends or dependencies on the RIS response have been drawn. Interfaces, including grain boundaries and precipitate-matrix interfaces can alter the RIS response. The grain boundary structure could change the point defect interaction at the GB. Changes in the point defect kinetics at a grain boundary could therefore alter the RIS response at the boundary. Furthermore, oxide nanoclusters in NF-ODS steel act as sinks for point defects under irradiation. The surface area and number density of these nanoclusters in NF-ODS steels could alter the point defect fluxes to GBs. Analytical microscopy techniques were conducted to determine the role of grain boundary structure and nanocluster dispersion on the RIS response in irradiated F/M steels. Here, a 9 wt. % Cr model alloy which simulates the structure of commercially available steels and 14YWT NF-ODS alloy was irradiated under numerous conditions. Both alloys were investigated using STEM/EDS and GB misorientation analysis. Experimental results indicate a preferential segregation of Cr to specific GB misorientations in the model F/M steel. Findings in the NF-ODS alloy indicates the stability of nanoclusters within the alloy alters the concentration gradient of the point defects near irradiated GBs. Based on these results, new theories on the role of interfaces in irradiated F/M steels was developed including a rate theory model which accounts for the GB misorientation angle within the RIS model. These theories will stimulate the development of new F/M steels which are highly resistant to RIS while in-service.</p> <div class="credits"> <p class="dwt_author">Field, Kevin G.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">326</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://dspace.mit.edu/handle/1721.1/73975"> <span id="translatedtitle">Reductive electrosynthesis of <span class="hlt">crystalline</span> metal-organic frameworks</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Electroreduction of oxoanions affords hydroxide equivalents that <span class="hlt">induce</span> selective deposition of <span class="hlt">crystalline</span> metal–organic frameworks (MOFs) on conductive surfaces. The method is illustrated by cathodic electrodeposition ...</p> <div class="credits"> <p class="dwt_author">Li, Minyuan</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">327</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/2003REDS..158..391K"> <span id="translatedtitle">Compositional trends of <span class="hlt">radiation-induced</span> effects in ternary systems of chalcogenide glasses</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 effect of gamma-irradiation on the optical transmittance spectra of pseudobinary stoichiometric and non-stoichiometric cuts of ternary systems of chalcogenide glasses was studied. The application of chemical-bond approach is proposed to explain the features of compositional dependencies of <span class="hlt">radiation-induced</span> effects in these materials. It is shown that free volume concept must be taken into consideration at the presence of different <span class="hlt">radiation</span>-sensitive structural units. The creation processes of coordination defects connected with the formation of free volume and coupled with the capability of the constituent atoms to passivation are the main factors determining the magnitude of the <span class="hlt">radiation-induced</span> effects in chalcogenide glasses.</p> <div class="credits"> <p class="dwt_author">Kovalskiy, A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">328</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=3998761"> <span id="translatedtitle">Numbers and proportions of leukemias in young people and adults <span class="hlt">induced</span> by <span class="hlt">radiation</span> of natural origin</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">Natural sources contribute a large fraction of the <span class="hlt">radiation</span> exposure of the general public. Under the linear no-threshold hypothesis risk decreases in proportion to decreasing dose without a threshold. We use recent estimates of doses to the red bone marrow to calculate the number and proportion of cases of leukemia in England <span class="hlt">induced</span> by natural <span class="hlt">radiation</span>. We calculate that 5–6% of cases of leukemia, excluding chronic lymphocytic leukemia, up to age 80 years are <span class="hlt">induced</span> by this background <span class="hlt">radiation</span>. In young people up to the age of 25 years the attributable fraction is 12–18%, substantially lower than a previous estimate. PMID:21334745</p> <div class="credits"> <p class="dwt_author">Kendall, Gerald; Little, Mark; Wakeford, Richard</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">329</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=2913836"> <span id="translatedtitle">Prophylaxis and management of acute <span class="hlt">radiation-induced</span> skin reactions: a systematic review of the 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=pmc">PubMed Central</a></p> <p class="result-summary"><span class="hlt">Radiation</span> therapy is a common treatment for cancer patients. One of the most common side effects of <span class="hlt">radiation</span> is acute skin reaction (<span class="hlt">radiation</span> dermatitis) that ranges from a mild rash to severe ulceration. Approximately 85% of patients treated with <span class="hlt">radiation</span> therapy will experience a moderate-to-severe skin reaction. Acute <span class="hlt">radiation-induced</span> skin reactions often lead to itching and pain, delays in treatment, and diminished aesthetic appearance—and subsequently to a decrease in quality of life. Surveys have demonstrated that a wide variety of topical, oral, and intravenous agents are used to prevent or to treat <span class="hlt">radiation-induced</span> skin reactions. We conducted a literature review to identify trials that investigated products for the prophylaxis and management of acute <span class="hlt">radiation</span> dermatitis. Thirty-nine studies met the pre-defined criteria, with thirty-three being categorized as prophylactic trials and six as management trials. For objective evaluation of skin reactions, the <span class="hlt">Radiation</span> Therapy Oncology Group criteria and the U.S. National Cancer Institute Common Toxicity Criteria were the most commonly used tools (65% of the studies). Topical corticosteroid agents were found to significantly reduce the severity of skin reactions; however, the trials of corticosteroids evaluated various agents, and no clear indication about a preferred corticosteroid has emerged. Amifostine and oral enzymes were somewhat effective in preventing <span class="hlt">radiation-induced</span> skin reactions in phase ii and phase iii trials respectively; further large randomized controlled trials should be undertaken to better investigate those products. Biafine cream (Ortho–McNeil Pharmaceuticals, Titusville, NJ, U.S.A.) was found not to be superior to standard regimes in the prevention of <span class="hlt">radiation-induced</span> skin reactions (n = 6). In conclusion, the evidence is insufficient to support the use of a particular agent for the prevention and management of acute <span class="hlt">radiation-induced</span> skin reactions. Future trials should focus on comparing agents and approaches that, in phase i and ii trials, suggest efficacy. These future phase iii randomized controlled trials must clearly distinguish between preventive and management strategies for <span class="hlt">radiation-induced</span> dermatitis. Only then can evidence-based guidelines be developed, with the hope of standardizing the approach across centres and of improving the prevention and management of <span class="hlt">radiation-induced</span> dermatitis. PMID:20697521</p> <div class="credits"> <p class="dwt_author">Salvo, N.; Barnes, E.; van Draanen, J.; Stacey, E.; Mitera, G.; Breen, D.; Giotis, A.; Czarnota, G.; Pang, J.; De Angelis, C.</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">330</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.nephy.chalmers.se/staff-pages/imre/publ/099RumjanaRadPhys.pdf"> <span id="translatedtitle"><span class="hlt">Radiation</span> Physics and Chemistry 61 (2001) 541543 Evolution of ion <span class="hlt">induced</span> point defects in silicon</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary"><span class="hlt">Radiation</span> Physics and Chemistry 61 (2001) 541­543 Evolution of ion <span class="hlt">induced</span> point defects in silicon <span class="hlt">induced</span> by 1 keV recoils in silicon crystals. The defect generation and evolution is simulated silicon. The different damage levels are related to the characteristics of the defect structure shortly</p> <div class="credits"> <p class="dwt_author">Pázsit, Imre</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">331</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/24727460"> <span id="translatedtitle">Mitigating the risk of <span class="hlt">radiation-induced</span> cancers: limitations and paradigms in drug development.</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 United States <span class="hlt">radiation</span> medical countermeasures (MCM) programme for radiological and nuclear incidents has been focusing on developing mitigators for the acute <span class="hlt">radiation</span> syndrome (ARS) and delayed effects of acute <span class="hlt">radiation</span> exposure (DEARE), and biodosimetry technologies to provide <span class="hlt">radiation</span> dose assessments for guiding treatment. Because a nuclear accident or terrorist incident could potentially expose a large number of people to low to moderate doses of ionising <span class="hlt">radiation</span>, and thus increase their excess lifetime cancer risk, there is an interest in developing mitigators for this purpose. This article discusses the current status, issues, and challenges regarding development of mitigators against <span class="hlt">radiation-induced</span> cancers. The challenges of developing mitigators for ARS include: the long latency between exposure and cancer manifestation, limitations of animal models, potential side effects of the mitigator itself, potential need for long-term use, the complexity of human trials to demonstrate effectiveness, and statistical power constraints for measuring health risks (and reduction of health risks after mitigation) following relatively low <span class="hlt">radiation</span> doses (<0.75 Gy). Nevertheless, progress in the understanding of the molecular mechanisms resulting in <span class="hlt">radiation</span> injury, along with parallel progress in dose assessment technologies, make this an opportune, if not critical, time to invest in research strategies that result in the development of agents to lower the risk of <span class="hlt">radiation-induced</span> cancers for populations that survive a significant <span class="hlt">radiation</span> exposure incident. PMID:24727460</p> <div class="credits"> <p class="dwt_author">Yoo, Stephen S; Jorgensen, Timothy J; Kennedy, Ann R; Boice, John D; Shapiro, Alla; Hu, Tom C-C; Moyer, Brian R; Grace, Marcy B; Kelloff, Gary J; Fenech, Michael; Prasanna, Pataje G S; Coleman, C Norman</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">332</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/23175338"> <span id="translatedtitle">Bystander effect <span class="hlt">induced</span> by UV <span class="hlt">radiation</span>; why should we be interested?</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 bystander effect, whose essence is an interaction of cells directly subjected to <span class="hlt">radiation</span> with adjacent non-subjected cells, via molecular signals, is an important component of ionizing <span class="hlt">radiation</span> action. However, knowledge of the bystander effect in the case of ultraviolet (UV) <span class="hlt">radiation</span> is quite limited. Reactive oxygen and nitrogen species generated by UV in exposed cells <span class="hlt">induce</span> bystander effects in non-exposed cells, such as reduction in clonogenic cell survival and delayed cell death, oxidative DNA damage and gene mutations, induction of micronuclei, lipid peroxidation and apoptosis. Although the bystander effect after UV <span class="hlt">radiation</span> has been recognized in cell culture systems, its occurrence in vivo has not been studied. However, solar UV <span class="hlt">radiation</span>, which is the main source of UV in the environment, may <span class="hlt">induce</span> in human dermal tissue an inflammatory response and immune suppression, events which can be considered as bystander effects of UV <span class="hlt">radiation</span>. The oxidative damage to DNA, genomic instability and the inflammatory response may lead to carcinogenesis. UV <span class="hlt">radiation</span> is considered one of the important etiologic factors for skin cancers, basal- and squamous-cell carcinomas and malignant melanoma. Based on the mechanisms of actions it seems that the UV-<span class="hlt">induced</span> bystander effect can have some impact on skin damage (carcinogenesis?), and probably on cells of other tissues. The paper reviews the existing data about the UV-<span class="hlt">induced</span> bystander effect and discusses a possible implication of this phenomenon for health risk.  PMID:23175338</p> <div class="credits"> <p class="dwt_author">Widel, Maria</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">333</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/6273510"> <span id="translatedtitle">Management of late <span class="hlt">radiation-induced</span> rectal injury after treatment of carcinoma of the uterus</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">Sixty-one of 1418 (4.3 per cent) patients treated with <span class="hlt">radiation</span> for carcinoma of the uterus from 1963 to 1983 had significant <span class="hlt">radiation-induced</span> complications of the intestine develop which required a surgical opinion considering further management. Ninety-three per cent of these complications involved the rectum. Florid proctitis resolved within two years of onset in 33 per cent of the patients who were managed conservatively while 22 per cent of the patients died of disseminated disease within the same time period. Surgical treatment was eventually necessary in 39 per cent of the patients who were initially treated conservatively for <span class="hlt">radiation</span> <span class="hlt">induced</span> proctitis. Rectal excision with coloanal sleeve anastomosis produced a satisfactory result in eight of 11 patients with severe <span class="hlt">radiation</span> injury involving the rectum. The incidence of <span class="hlt">radiation-induced</span> and malignant rectovaginal fistula were similar (1 per cent), but disease-<span class="hlt">induced</span> symptoms tended to occur earlier after primary treatment (a median of eight months) compared with <span class="hlt">radiation-induced</span> symptoms (a median of 16 months).</p> <div class="credits"> <p class="dwt_author">Allen-Mersh, T.G.; Wilson, E.J.; Hope-Stone, H.F.; Mann, C.V.</p> <p class="dwt_publisher"></p> <p class="publishDate">1987-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">334</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/1094911"> <span id="translatedtitle">Detecting <span class="hlt">Radiation-Induced</span> Injury Using Rapid 3D Variogram Analysis of CT Images of Rat Lungs</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">A new heterogeneity analysis approach to discern <span class="hlt">radiation-induced</span> lung damage was tested on CT images of irradiated rats. The method, combining octree decomposition with variogram analysis, demonstrated a significant correlation with <span class="hlt">radiation</span> exposure levels, whereas conventional measurements and pulmonary function tests did not. The results suggest the new approach may be highly sensitive for assessing even subtle <span class="hlt">radiation-induced</span> changes</p> <div class="credits"> <p class="dwt_author">Jacob, Rick E.; Murphy, Mark K.; Creim, Jeffrey A.; Carson, James P.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-10-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">335</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/12359287"> <span id="translatedtitle"><span class="hlt">Radiation-induced</span> aortoesophageal fistula: an unusual case of massive upper gastrointestinal bleeding.</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">Aortoesophageal fistula (AEF) is an unusual cause of massive upper gastrointestinal bleeding. Thoracic aortic aneurysm is the most common etiology of primary AEF followed by, respectively, foreign body ingestion, esophageal malignancy, and postsurgical fistulization. <span class="hlt">Radiation-induced</span> damage to the great vessels is well recognized and some authors in the past have suggested that AEF may be caused by radiotherapy. However, previous case reports of <span class="hlt">radiation-induced</span> AEF involved patients who received radiotherapy for esophageal carcinoma, and precise histopathologic differentiation between AEF secondary to esophageal malignancy and that <span class="hlt">induced</span> by <span class="hlt">radiation</span> was difficult. We present here the unique case of a patient with a non-esophageal carcinoma who received radiotherapy before the development of an AEF, thus providing further evidence for the role of <span class="hlt">radiation</span> injury in the development of this condition. As well, we discuss current opinion regarding etiology, clinical presentation, diagnosis, and management of this entity. PMID:12359287</p> <div class="credits"> <p class="dwt_author">Sivaraman, Sujith K; Drummond, Robert</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-08-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">336</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=3854433"> <span id="translatedtitle">Effect of ozone oxidative preconditioning in preventing early <span class="hlt">radiation-induced</span> lung injury in rats</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</span> causes its biological effects mainly through oxidative damage <span class="hlt">induced</span> by reactive oxygen species. Previous studies showed that ozone oxidative preconditioning attenuated pathophysiological events mediated by reactive oxygen species. As inhalation of ozone <span class="hlt">induces</span> lung injury, the aim of this study was to examine whether ozone oxidative preconditioning potentiates or attenuates the effects of irradiation on the lung. Rats were subjected to total body irradiation, with or without treatment with ozone oxidative preconditioning (0.72 mg/kg). Serum proinflammatory cytokine levels, oxidative damage markers, and histopathological analysis were compared at 6 and 72 h after total body irradiation. Irradiation significantly increased lung malondialdehyde levels as an end-product of lipoperoxidation. Irradiation also significantly decreased lung superoxide dismutase activity, which is an indicator of the generation of oxidative stress and an early protective response to oxidative damage. Ozone oxidative preconditioning plus irradiation significantly decreased malondialdehyde levels and increased the activity of superoxide dismutase, which might indicate protection of the lung from <span class="hlt">radiation-induced</span> lung injury. Serum tumor necrosis factor alpha and interleukin-1 beta levels, which increased significantly following total body irradiation, were decreased with ozone oxidative preconditioning. Moreover, ozone oxidative preconditioning was able to ameliorate <span class="hlt">radiation-induced</span> lung injury assessed by histopathological evaluation. In conclusion, ozone oxidative preconditioning, repeated low-dose intraperitoneal administration of ozone, did not exacerbate <span class="hlt">radiation-induced</span> lung injury, and, on the contrary, it provided protection against <span class="hlt">radiation-induced</span> lung damage. PMID:23969972</p> <div class="credits"> <p class="dwt_author">Bakkal, B.H.; Gultekin, F.A.; Guven, B.; Turkcu, U.O.; Bektas, S.; Can, M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">337</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=20040087650&hterms=DNA&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DDNA"> <span id="translatedtitle">Clustered DNA damages <span class="hlt">induced</span> in human hematopoietic cells by low doses of ionizing <span class="hlt">radiation</span></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> <span class="hlt">induces</span> clusters of DNA damages--oxidized bases, abasic sites and strand breaks--on opposing strands within a few helical turns. Such damages have been postulated to be difficult to repair, as are double strand breaks (one type of cluster). We have shown that low doses of low and high linear energy transfer (LET) <span class="hlt">radiation</span> <span class="hlt">induce</span> such damage clusters in human cells. In human cells, DSB are about 30% of the total of complex damages, and the levels of DSBs and oxidized pyrimidine clusters are similar. The dose responses for cluster induction in cells can be described by a linear relationship, implying that even low doses of ionizing <span class="hlt">radiation</span> can produce clustered damages. Studies are in progress to determine whether clusters can be produced by mechanisms other than ionizing <span class="hlt">radiation</span>, as well as the levels of various cluster types formed by low and high LET <span class="hlt">radiation</span>.</p> <div class="credits"> <p class="dwt_author">Sutherland, Betsy M.; Bennett, Paula V.; Cintron-Torres, Nela; Hada, Megumi; Trunk, John; Monteleone, Denise; Sutherland, John C.; Laval, Jacques; Stanislaus, Marisha; Gewirtz, Alan</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">338</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/23849504"> <span id="translatedtitle">Biological consequences of <span class="hlt">radiation-induced</span> DNA damage: relevance to radiotherapy.</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">DNA damage of exposed tumour tissue leading to cell death is one of the detrimental effects of ionising <span class="hlt">radiation</span> that is exploited, with beneficial consequences, for radiotherapy. The pattern of the discrete energy depositions during passage of the ionising track of <span class="hlt">radiation</span> defines the spatial distribution of lesions <span class="hlt">induced</span> in DNA with a fraction of the DNA damage sites containing clusters of lesions, formed over a few nanometres, against a background of endogenously <span class="hlt">induced</span> individual lesions. These clustered DNA damage sites, which may be considered as a signature of ionising <span class="hlt">radiation</span>, underlie the deleterious biological consequences of ionising <span class="hlt">radiation</span>. The concepts developed rely in part on the fact that ionising <span class="hlt">radiation</span> creates significant levels of clustered DNA damage, including complex double-strand breaks (DSB), to kill tumour cells as clustered damage sites are difficult to repair. This reduced repairability of clustered DNA damage using specific repair pathways is exploitable in radiotherapy for the treatment of cancer. We discuss some potential strategies to enhance radiosensitivity by targeting the repair pathways of <span class="hlt">radiation-induced</span> clustered damage and complex DNA DSB, through inhibition of specific proteins that are not required in the repair pathways for endogenous damage. The variety and severity of DNA damage from ionising <span class="hlt">radiation</span> is also influenced by the tumour microenvironment, being especially sensitive to the oxygen status of the cells. For instance, nitric oxide is known to influence the types of damage <span class="hlt">induced</span> by <span class="hlt">radiation</span> under hypoxic conditions. A potential strategy based on bioreductive activation of pro-drugs to release nitric oxide is discussed as an approach to deliver nitric oxide to hypoxic tumours during radiotherapy. The ultimate aim of this review is to stimulate thinking on how knowledge of the complexity of <span class="hlt">radiation-induced</span> DNA damage may contribute to the development of adjuncts to radiotherapy. PMID:23849504</p> <div class="credits"> <p class="dwt_author">Lomax, M E; Folkes, L K; O'Neill, P</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-10-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">339</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/17265150"> <span id="translatedtitle">Protective effects of L-selenomethionine on space <span class="hlt">radiation</span> <span class="hlt">induced</span> changes in gene expression.</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> can produce adverse biological effects in astronauts during space travel. Of particular concern are the types of <span class="hlt">radiation</span> from highly energetic, heavy, charged particles known as HZE particles. The aims of our studies are to characterize HZE particle <span class="hlt">radiation</span> <span class="hlt">induced</span> biological effects and evaluate the effects of L-selenomethionine (SeM) on these adverse biological effects. In this study, microarray technology was used to measure HZE <span class="hlt">radiation</span> <span class="hlt">induced</span> changes in gene expression, as well as to evaluate modulation of these changes by SeM. Human thyroid epithelial cells (HTori-3) were irradiated (1 GeV/n iron ions) in the presence or in the absence of 5 microM SeM. At 6 h post-irradiation, all cells were harvested for RNA isolation. Gene Chip U133Av2 from Affymetrix was used for the analysis of gene expression, and ANOVA and EASE were used for a determination of the genes and biological processes whose differential expression is statistically significant. Results of this microarray study indicate that exposure to small doses of <span class="hlt">radiation</span> from HZE particles, 10 and 20 cGy from iron ions, <span class="hlt">induces</span> statistically significant differential expression of 196 and 610 genes, respectively. In the presence of SeM, differential expression of 77 out of 196 genes (exposure to 10 cGy) and 336 out of 610 genes (exposure to 20 cGy) is abolished. In the presence or in the absence of SeM, <span class="hlt">radiation</span> from HZE particles <span class="hlt">induces</span> differential expression of genes whose products have roles in the induction of G1/S arrest during the mitotic cell cycle, as well as heat shock proteins. Some of the genes, whose expressions were affected by <span class="hlt">radiation</span> from HZE particles and were unchanged in irradiated cells treated with SeM, have been shown to have altered expression levels in cancer cells. The conclusions of this report are that <span class="hlt">radiation</span> from HZE particles can <span class="hlt">induce</span> differential expression of many genes, some of which are known to play roles in the same processes that have been shown to be activated in cells exposed to <span class="hlt">radiation</span> from photons (like cell cycle arrest in G1/S), and that supplementation with SeM abolishes HZE particle-<span class="hlt">induced</span> differential expression of many genes. Understanding the roles that these genes play in the <span class="hlt">radiation-induced</span> transformation of cells may help to decipher the origins of <span class="hlt">radiation-induced</span> cancer. PMID:17265150</p> <div class="credits"> <p class="dwt_author">Stewart, J; Ko, Y-H; Kennedy, A R</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">340</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/2013JAP...114f4104Z"> <span id="translatedtitle">Surface photoconductivity of organosilicate glass dielectrics <span class="hlt">induced</span> by vacuum-ultraviolet <span class="hlt">radiation</span></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 temporary increase in the electrical surface conductivity of low-k organosilicate glass (SiCOH) during exposure to vacuum-ultraviolet <span class="hlt">radiation</span> (VUV) is investigated. To measure the photoconductivity, patterned "comb structures" are deposited on dielectric films and exposed to synchrotron <span class="hlt">radiation</span> in the range of 8-25 eV, which is in the energy range of most plasma vacuum-ultraviolet <span class="hlt">radiation</span>. The change in photo surface conductivity <span class="hlt">induced</span> by VUV <span class="hlt">radiation</span> may be beneficial in limiting charging damage of dielectrics by depleting the plasma-deposited charge.</p> <div class="credits"> <p class="dwt_author">Zheng, H.; Nichols, M. T.; Pei, D.; Nishi, Y.; Shohet, J. L.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-08-01</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_16");' 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");' 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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">341</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/2011RaPC...80..957C"> <span id="translatedtitle"><span class="hlt">Radiation</span> <span class="hlt">induced</span> synthesis of powder yttrium aluminium garnet</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">Yttrium-aluminium garnet powders were prepared from aqueous solutions containing yttrium nitrate and aluminium chloride or nitrate via irradiation with accelerated electrons or UV light and via consequent calcination of formed solid phase. UV light seems to be more convenient for yttrium-aluminium garnet preparation; both types of irradiation yield <span class="hlt">crystalline</span> Y 3Al 5O 12 phase after 1 h calcination at 1000 °C in air, but some amounts of yttrium oxide and aluminium oxide were also detected in calcinated solid phase formed under accelerated electrons irradiation. Preliminary radioluminescence and thermoluminescence measurements were performed to further evaluate prepared materials. Intensive radioluminescence typical for Ce 3+ doped structure was observed; thermoluminescence glow curves show distinctive peaks at 135-140 and 240-250 °C.</p> <div class="credits"> <p class="dwt_author">?uba, Václav; Indrei, Jakub; Mú?ka, Viliam; Nikl, Martin; Beitlerová, Alena; Pospíšil, Milan; Jakubec, Ivo</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-09-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">342</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ece.rice.edu/~kono/CerneetAl97APL.pdf"> <span id="translatedtitle">Near-infrared sideband generation <span class="hlt">induced</span> by intense far-infrared <span class="hlt">radiation</span> in GaAs quantum wells</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Near-infrared sideband generation <span class="hlt">induced</span> by intense far-infrared <span class="hlt">radiation</span> in GaAs quantum wells J illuminated with near-infrared NIR <span class="hlt">radiation</span> at frequency nir and intense far-infrared FIR <span class="hlt">radiation</span> from and quenching of photoluminescence PL .8,9 The nonlinear interaction of FIR and near-infrared NIR <span class="hlt">radiation</span></p> <div class="credits"> <p class="dwt_author">Kono, Junichiro</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">343</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/18957831"> <span id="translatedtitle">High LET heavy ion <span class="hlt">radiation</span> <span class="hlt">induces</span> p53-independent apoptosis.</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">Conventional clinical treatments with X-rays provide an effective modality for widely various human cancers, however, therapeutic results are sometimes poor. Many mutations have been reported to be in the p53 gene in advanced human cancers. The p53 plays a pivotal role in the pathway which controls apoptosis, cell growth and cell proliferation, and mutations or deletions in the p53 gene lead to resistance to cancer therapy. The involvement of the p53 gene in determining the sensitivity of many cell types toward low linear energy transfer (LET) <span class="hlt">radiation</span> is now well established. In contrast to low LET <span class="hlt">radiation</span>, high LET <span class="hlt">radiation</span> has several potential advantages over X-rays, one of which is the fact that its effects may be independent of cellular p53 gene status. It is conceivable that effective future therapeutic strategies may be designed on the basis of genetic and biochemical events involved in cell death. Therefore, the accurate characterization and quantification of the mode of cell death, such as apoptosis and necrosis, has become increasingly important for the further understanding of the biological effectiveness of high LET <span class="hlt">radiation</span>. This review discusses the mechanisms of p53-independent apoptosis by high LET <span class="hlt">radiation</span>. PMID:18957831</p> <div class="credits"> <p class="dwt_author">Mori, Eiichiro; Takahashi, Akihisa; Yamakawa, Nobuhiro; Kirita, Tadaaki; Ohnishi, Takeo</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">344</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=19920004637&hterms=fast+neutron+shielding&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dfast%2Bneutron%2Bshielding"> <span id="translatedtitle">Naturally <span class="hlt">induced</span> secondary <span class="hlt">radiation</span> in interplanetary space: Preliminary analyses for gamma <span class="hlt">radiation</span> and radioisotope production from thermal neutron activation</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">Thermal neutron activation analyses were carried out for various space systems components to determine gamma <span class="hlt">radiation</span> dose rates and food <span class="hlt">radiation</span> contamination levels. The space systems components selected were those for which previous <span class="hlt">radiation</span> studies existed. These include manned space vehicle <span class="hlt">radiation</span> shielding, liquid hydrogen propellant tanks for a Mars mission, and a food supply used as space vehicle <span class="hlt">radiation</span> shielding. The computational method used is based on the fast neutron distribution generated by the BRYNTRN and HZETRN transport codes for Galactic Cosmic Rays (GCR) at solar minimum conditions and intense solar flares in space systems components. The gamma dose rates for soft tissue are calculated for water and aluminum space vehicle slab shields considering volumetric source self-attenuation and exponential buildup factors. In the case of the lunar habitat with regolith shielding, a completely exposed spherical habitat was assumed for mathematical convenience and conservative calculations. Activation analysis of the food supply used as <span class="hlt">radiation</span> shielding is presented for four selected nutrients: potassium, calcium, sodium, and phosphorus. Radioactive isotopes that could represent a health hazard if ingested are identified and their concentrations are identified. For nutrients soluble in water, it was found that all <span class="hlt">induced</span> radioactivity was below the accepted maximum permissible concentrations.</p> <div class="credits"> <p class="dwt_author">Plaza-Rosado, Heriberto</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">345</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/24828078"> <span id="translatedtitle">PHD inhibition mitigates and protects against <span class="hlt">radiation-induced</span> gastrointestinal toxicity via HIF2.</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> gastrointestinal (GI) toxicity can be a major source of morbidity and mortality after <span class="hlt">radiation</span> exposure. There is an unmet need for effective preventative or mitigative treatments against the potentially fatal diarrhea and water loss <span class="hlt">induced</span> by <span class="hlt">radiation</span> damage to the GI tract. We report that prolyl hydroxylase inhibition by genetic knockout or pharmacologic inhibition of all PHD (prolyl hydroxylase domain) isoforms by the small-molecule dimethyloxallyl glycine (DMOG) increases hypoxia-<span class="hlt">inducible</span> factor (HIF) expression, improves epithelial integrity, reduces apoptosis, and increases intestinal angiogenesis, all of which are essential for radioprotection. HIF2, but not HIF1, is both necessary and sufficient to prevent <span class="hlt">radiation-induced</span> GI toxicity and death. Increased vascular endothelial growth factor (VEGF) expression contributes to the protective effects of HIF2, because inhibition of VEGF function reversed the radioprotection and radiomitigation afforded by DMOG. Additionally, mortality from abdominal or total body irradiation was reduced even when DMOG was given 24 hours after exposure. Thus, prolyl hydroxylase inhibition represents a treatment strategy to protect against and mitigate GI toxicity from both therapeutic <span class="hlt">radiation</span> and potentially lethal <span class="hlt">radiation</span> exposures. PMID:24828078</p> <div class="credits"> <p class="dwt_author">Taniguchi, Cullen M; Miao, Yu Rebecca; Diep, Anh N; Wu, Colleen; Rankin, Erinn B; Atwood, Todd F; Xing, Lei; Giaccia, Amato J</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-05-14</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">346</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/25072018"> <span id="translatedtitle">Mitochondria regulate DNA damage and genomic instability <span class="hlt">induced</span> by high LET <span class="hlt">radiation</span>.</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">High linear energy transfer (LET) <span class="hlt">radiation</span> including ? particles and heavy ions is the major type of <span class="hlt">radiation</span> find in space and is considered a potential health risk for astronauts. Even though the chance that these high LET particles traversing through the cytoplasm of cells is higher than that through the nuclei, the contribution of targeted cytoplasmic irradiation, to the induction of genomic instability and other chromosomal damages <span class="hlt">induced</span> by high LET <span class="hlt">radiation</span> is not known. In the present study, we investigated whether mitochondria are the potential cytoplasmic target of high LET <span class="hlt">radiation</span> in mediating cellular damage using a mitochondrial DNA (mtDNA) depleted (?(0)) human small airway epithelial (SAE) cell model and a precision charged particle microbeam with a beam width of merely one micron. Targeted cytoplasmic irradiation by high LET ? particles <span class="hlt">induced</span> DNA oxidative damage and double strand breaks in wild type ?(+) SAE cells. Furthermore, there was a significant increase in autophagy, micronuclei, which is an indication of genomic instability, together with the activation of nuclear factor kappa-B (NF-?B) and mitochondrial <span class="hlt">inducible</span> nitric oxide synthase (iNOS) signaling pathways in ?(+) SAE cells. In contrast, ?(0) SAE cells exhibited a significantly lower response to these same endpoints examined after cytoplasmic irradiation with high LET ? particles. The results indicate that mitochondria are essential in mediating cytoplasmic <span class="hlt">radiation</span> <span class="hlt">induced</span> genotoxic damage in mammalian cells. Furthermore, the findings may shed some light in the design of countermeasures for space <span class="hlt">radiation</span>. PMID:25072018</p> <div class="credits"> <p class="dwt_author">Zhang, Bo; Davidson, Mercy M; Hei, Tom K</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">347</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=20130013689&hterms=chen&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dchen"> <span id="translatedtitle">Chromatin Folding, Fragile Sites, and Chromosome Aberrations <span class="hlt">Induced</span> by Low- and High- LET <span class="hlt">Radiation</span></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 previously demonstrated non-random distributions of breaks involved in chromosome aberrations <span class="hlt">induced</span> by low- and high-LET <span class="hlt">radiation</span>. To investigate the factors contributing to the break point distribution in <span class="hlt">radiation-induced</span> chromosome aberrations, human epithelial cells were fixed in G1 phase. Interphase chromosomes were hybridized with a multicolor banding in situ hybridization (mBAND) probe for chromosome 3 which distinguishes six regions of the chromosome in separate colors. After the images were captured with a laser scanning confocal microscope, the 3-dimensional structure of interphase chromosome 3 was reconstructed at multimega base pair scale. Specific locations of the chromosome, in interphase, were also analyzed with bacterial artificial chromosome (BAC) probes. Both mBAND and BAC studies revealed non-random folding of chromatin in interphase, and suggested association of interphase chromatin folding to the <span class="hlt">radiation-induced</span> chromosome aberration hotspots. We further investigated the distribution of genes, as well as the distribution of breaks found in tumor cells. Comparisons of these distributions to the <span class="hlt">radiation</span> hotspots showed that some of the <span class="hlt">radiation</span> hotspots coincide with the frequent breaks found in solid tumors and with the fragile sites for other environmental toxins. Our results suggest that multiple factors, including the chromatin structure and the gene distribution, can contribute to <span class="hlt">radiation-induced</span> chromosome aberrations.</p> <div class="credits"> <p class="dwt_author">Zhang, Ye; Cox, Bradley; Asaithamby, Aroumougame; Chen, David J.; Wu, Honglu</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">348</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/22149591"> <span id="translatedtitle">A Prospective Cohort Study on <span class="hlt">Radiation-induced</span> Hypothyroidism: Development of an NTCP Model</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: To establish a multivariate normal tissue complication probability (NTCP) model for <span class="hlt">radiation-induced</span> hypothyroidism. Methods and Materials: The thyroid-stimulating hormone (TSH) level of 105 patients treated with (chemo-) <span class="hlt">radiation</span> therapy for head-and-neck cancer was prospectively measured during a median follow-up of 2.5 years. Hypothyroidism was defined as elevated serum TSH with decreased or normal free thyroxin (T4). A multivariate logistic regression model with bootstrapping was used to determine the most important prognostic variables for <span class="hlt">radiation-induced</span> hypothyroidism. Results: Thirty-five patients (33%) developed primary hypothyroidism within 2 years after <span class="hlt">radiation</span> therapy. An NTCP model based on 2 variables, including the mean thyroid gland dose and the thyroid gland volume, was most predictive for <span class="hlt">radiation-induced</span> hypothyroidism. NTCP values increased with higher mean thyroid gland dose (odds ratio [OR]: 1.064/Gy) and decreased with higher thyroid gland volume (OR: 0.826/cm{sup 3}). Model performance was good with an area under the curve (AUC) of 0.85. Conclusions: This is the first prospective study resulting in an NTCP model for <span class="hlt">radiation-induced</span> hypothyroidism. The probability of hypothyroidism rises with increasing dose to the thyroid gland, whereas it reduces with increasing thyroid gland volume.</p> <div class="credits"> <p class="dwt_author">Boomsma, Marjolein J.; Bijl, Hendrik P.; Christianen, Miranda E.M.C.; Beetz, Ivo; Chouvalova, Olga; Steenbakkers, Roel J.H.M. [Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands); Laan, Bernard F.A.M. van der [Department of Otorhinolaryngology/Head and Neck Surgery, University Medical Center Groningen, University of Groningen, Groningen (Netherlands); Wolffenbuttel, Bruce H.R. [Department of Endocrinology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands)] [Department of Endocrinology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands); Oosting, Sjoukje F. [Department of Medical Oncology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands)] [Department of Medical Oncology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands); Schilstra, Cornelis [Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands)] [Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands); Langendijk, Johannes A., E-mail: j.a.langendijk@umcg.nl [Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands)</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-11-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">349</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/6085815"> <span id="translatedtitle">Studies of oxidative degradation of polymers <span class="hlt">induced</span> by ionizing <span class="hlt">radiation</span></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"><span class="hlt">Radiation</span> effects on polymers in the presence of air are characterized by complicated phenomena such as dose-rate effects and post-irradiation degradation. These time-dependent effects can be understood in these terms: (1) features of the free radical chain-reaction chemistry underlying the oxidation, and (2) oxygen diffusion effects. A profiling technique has been developed to study heterogeneous degradation resulting from oxygen diffusion, and kinetic schemes have been developed to allow long-term aging predictions from short-term high dose-rate experiments. Low molecular weight additives which act either as free-radical scavengers or else as energy-scavengers are effective as stabilizers in <span class="hlt">radiation</span>-oxidation environments. Non-radical oxidation mechanisms, involving species such as ozone, can also be important in the <span class="hlt">radiation</span>-oxidation of polymers. 18 refs., 15 figs.</p> <div class="credits"> <p class="dwt_author">Clough, R.L.; Gillen, K.T.</p> <p class="dwt_publisher"></p> <p class="publishDate">1989-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">350</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/2004cosp...35.1514H"> <span id="translatedtitle"><span class="hlt">Radiation</span> <span class="hlt">induced</span> cell inactivation as cause for cancer promotion</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">In space research, estimates of health risks from high-LET <span class="hlt">radiation</span> are needed. Features of several applications of the biologically based two step clonal expansion (TSCE) model on data with the high-LET <span class="hlt">radiation</span>, normally alpha particles, from radon and from Thorotrast are reviewed. One conclusion is that <span class="hlt">radiation</span> might not only influence the initiating event in carcinogenesis, but may also act as a promoter. A possible mechanism which gives a promoting action from cell inactivation is presented for the organs "lung", with a two-dimensional arrangement of the cells at risk, and for "liver" where the sensitive cells are distributed in all three dimensions. Inferences for dose-response curves at low doses and dose rates are drawn.</p> <div class="credits"> <p class="dwt_author">Heidenreich, W. F.; Paretzke, H. G.</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">351</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/2012rdbs.book..203M"> <span id="translatedtitle">Monte Carlo Methods to Model <span class="hlt">Radiation</span> Interactions and <span class="hlt">Induced</span> Damage</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">This review is devoted to the analysis of some Monte Carlo (MC) simulation programmes which have been developed to describe <span class="hlt">radiation</span> interaction with biologically relevant materials. Current versions of the MC codes Geant4 (GEometry ANd Tracking 4), PENELOPE (PENetration and Energy Loss of Positrons and Electrons), EPOTRAN (Electron and POsitron TRANsport), and LEPTS (Low-Energy Particle Track Simulation) are described. Mean features of each model, as the type of <span class="hlt">radiation</span> to consider, the energy range covered by primary and secondary particles, the type of interactions included in the simulation and the considered target geometries are discussed. Special emphasis lies on recent developments that, together with (still emerging) new databases that include adequate data for biologically relevant materials, bring us continuously closer to a realistic, physically meaningful description of <span class="hlt">radiation</span> damage in biological tissues.</p> <div class="credits"> <p class="dwt_author">Muñoz, Antonio; Fuss, Martina C.; Cortés-Giraldo, M. A.; Incerti, Sébastien; Ivanchenko, Vladimir; Ivanchenko, Anton; Quesada, J. M.; Salvat, Francesc; Champion, Christophe; Gómez-Tejedor, Gustavo García</p> <p class="dwt_publisher"></p> <p class="publishDate"></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/2009PhRvB..79c3406R"> <span id="translatedtitle">Thermal-<span class="hlt">radiation-induced</span> nonequilibrium carriers in intrinsic graphene</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">We have examined an intrinsic graphene connected to the phonon thermostat at temperature T under irradiation of thermal photons with temperature Tr , different from T . The distribution of nonequilibrium electron-hole pairs was obtained for the cases when the interparticle scattering is unessential and when the Coulomb scattering dominates. For the first case, the distribution function is determined by the interplay of intraband relaxation of energy due to acoustic phonons and interband <span class="hlt">radiative</span> transitions caused by the thermal <span class="hlt">radiation</span>. For the alter case, the quasiequilibrium distribution with effective temperature and nonequilibrium concentration, determined through balance equations, is realized. Due to the effect of thermal <span class="hlt">radiation</span> with temperature Tr?T , concentration and conductivity of carriers in graphene are modified essentially. It is demonstrated that at Tr>T , the negative interband absorption caused by the inversion of carriers distribution can occur.</p> <div class="credits"> <p class="dwt_author">Romanets, P. N.; Vasko, F. T.; Strikha, M. V.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</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=93191"> <span id="translatedtitle">Insertion or Deletion of the Cheo Box Modifies <span class="hlt">Radiation</span> <span class="hlt">Inducibility</span> of Clostridium Promoters</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"><span class="hlt">Radiation-inducible</span> promoters are being used in many viral vector systems to obtain spatial and temporal control of gene expression. It was previously proven that <span class="hlt">radiation-induced</span> gene expression can also be obtained in a bacterial vector system using anaerobic apathogenic clostridia. The effect of <span class="hlt">radiation</span> <span class="hlt">inducibility</span> was detected using mouse tumor necrosis factor alpha (mTNF-?) as a model protein under regulation of the <span class="hlt">radiation-inducible</span> recA promoter. In this report, experiments are described in which this recA promoter was modified in order to increase <span class="hlt">radiation</span> responsiveness. Incorporation of an extra Cheo box in the recA promoter region resulted in an increase in mTNF-? secretion from 44% for the wild-type promoter to 412% for the promoter with an extra Cheo box after a single irradiation dose of 2 Gy. Deletion of the Cheo box in the promoter region eliminated <span class="hlt">radiation</span> <span class="hlt">inducibility</span>. These results prove that the Cheo box in the recA promoter is indeed the <span class="hlt">radiation</span>-responsive element. We also tested whether we could <span class="hlt">induce</span> the constitutive endo-?-1,4-glucanase promoter (eglA) via ionizing irradiation by introducing a Cheo box in the promoter region. While the use of the constitutive promoter did not lead to an increase in mTNF-? secretion after irradiation, the introduction of a Cheo box resulted in a 242% increase in mTNF-? secretion. Reverse transcriptase PCR of RNA samples isolated from irradiated and nonirradiated bacterial cultures demonstrated that the increase in secretion was the result of enhanced transcription of the mTNF-? gene. PMID:11571144</p> <div class="credits"> <p class="dwt_author">Nuyts, S.; Van Mellaert, L.; Barbé, S.; Lammertyn, E.; Theys, J.; Landuyt, W.; Bosmans, E.; Lambin, P.; Anné, J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</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://adsabs.harvard.edu/abs/2013JNuM..442..518O"> <span id="translatedtitle">Effect of <span class="hlt">radiation-induced</span> damage on deuterium retention in tungsten, tungsten coatings and Eurofer</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">An influence of <span class="hlt">radiation-induced</span> damage on hydrogen isotope retention and transport in a bulk tungsten (W), dense nano-structured W coatings and Eurofer was investigated under well-defined laboratory conditions. <span class="hlt">Radiation-induced</span> defects in W materials and Eurofer were created by irradiation with 20 MeV W ions. Following the damage production, samples were exposed to low-energy deuterium plasma. The deuterium (D) retention in each sample was subsequently measured by nuclear reaction analysis (NRA) for the depth profiling up to 6 ?m. It was shown that the D retention at <span class="hlt">radiation-induced</span> damage is almost equivalent for different W grades after irradiation at high enough fluence. The kinetic of D migration and trapping in damaged area as well as recovery of <span class="hlt">radiation-induced</span> damage were investigated by loading at different temperatures. It was shown that deuterium retention in tungsten in fusion environment will be dominated by <span class="hlt">radiation-induced</span> effect in a wide range of investigated temperatures, namely, from room temperature to 1100 K. Whereas displacement damage produced in Eurofer has less pronounced effect on the deuterium accumulation.</p> <div class="credits"> <p class="dwt_author">Ogorodnikova, O. V.; Sugiyama, K.</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">355</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=3393340"> <span id="translatedtitle">Amelioration of <span class="hlt">radiation-induced</span> hematopoietic and gastrointestinal damage by Ex-RAD® in 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">The aim of the present study was to assess recovery from hematopoietic and gastrointestinal damage by Ex-RAD®, also known as ON01210.Na (4-carboxystyryl-4-chlorobenzylsulfone, sodium salt), after total body <span class="hlt">radiation</span>. In our previous study, we reported that Ex-RAD, a small-molecule radioprotectant, enhances survival of mice exposed to gamma <span class="hlt">radiation</span>, and prevents <span class="hlt">radiation-induced</span> apoptosis as measured by the inhibition of <span class="hlt">radiation-induced</span> protein 53 (p53) expression in cultured cells. We have expanded this study to determine best effective dose, dose-reduction factor (DRF), hematological and gastrointestinal protection, and in vivo inhibition of p53 signaling. A total of 500 mg/kg of Ex-RAD administered at 24 h and 15 min before <span class="hlt">radiation</span> resulted in a DRF of 1.16. Ex-RAD ameliorated <span class="hlt">radiation-induced</span> hematopoietic damage as monitored by the accelerated recovery of peripheral blood cells, and protection of granulocyte macrophage colony-forming units (GM-CFU) in bone marrow. Western blot analysis on spleen indicated that Ex-RAD treatment inhibited p53 phosphorylation. Ex-RAD treatment reduces terminal deoxynucleotidyl transferase mediated dUTP nick end labeling assay (TUNEL)-positive cells in jejunum compared with vehicle-treated mice after <span class="hlt">radiation</span> injury. Finally, Ex-RAD preserved intestinal crypt cells compared with the vehicle control at 13 and 14 Gy. The results demonstrated that Ex-RAD ameliorates <span class="hlt">radiation-induced</span> peripheral blood cell depletion, promotes bone marrow recovery, reduces p53 signaling in spleen and protects intestine from <span class="hlt">radiation</span> injury. PMID:22843617</p> <div class="credits"> <p class="dwt_author">Ghosh, Sanchita P.; Kulkarni, Shilpa; Perkins, Michael W.; Hieber, Kevin; Pessu, Roli L.; Gambles, Kristen; Maniar, Manoj; Kao, Tzu-Cheg; Seed, Thomas M.; Kumar, K. Sree</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">356</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/924961"> <span id="translatedtitle"><span class="hlt">Radiation</span> <span class="hlt">Induced</span> Stress Relaxation in Silicone and Polyurethane Elastomers</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">Many different materials are used in the National Ignition Facility, NIF, located at Lawrence Livermore National Laboratory, LLNL. Some of these are exposed to significant doses of ionizing <span class="hlt">radiation</span>. Two elastomers are of special interest because they are used in sealing applications with long expected lifetimes. These are LPU4, a polyurethane formulated at LLNL, and Dow Corning DC93-500, a silicone RTV elastomer. In 2004 a program to determine the impact of ionizing <span class="hlt">radiation</span> on the stress relaxation and compression set characteristics of these two elastomers was undertaken. Since the materials are used in continuous compression and must reliably seal, the primary test utilized was a stress relaxation test. This test provides insight into the ability of a seal to remain functional in a static seal. The test determines how much residual force remains after a certain period of time under compression. The temperature and absorbed <span class="hlt">radiation</span> dose can dramatically impact this property. In this study the only independent environmental variable studied is the effect of <span class="hlt">radiation</span> at ambient temperatures. Two levels of <span class="hlt">radiation</span> exposure were studied, 1 MRad, and 10 MRad. One of the independent test parameters is the compression deflection during storage and in this test the value used was 25%. The need for a compression retention mechanism ruled out <span class="hlt">radiation</span> exposure in the compressed direction since the high atomic number materials for that device would block the <span class="hlt">radiation</span>. Therefore, an annular ring was chosen for the specimen shape. The procedures are, as closely as possible, based on ASTM D 6147-97. Since the data is readily obtained at the end of the stress relaxation test, the samples were also evaluated for compression set. Compression set is the essentially permanent deformation incurred in a seal after the seal is compressed for some period of time and then unloaded. Though this is indicative of potential sealing reliability, it is not as direct an indicator of seal performance as is stress relaxation. Compression set does not yield any useable, quantified information but is an indicator of viscoelastic deformation with time. The needed thickness measurements were obtained both from the unloading curves and direct measurement in general accordance with ASTM D395-03. The <span class="hlt">radiation</span> source for this testing was the Co60 gamma source located at Lawrence Livermore National Laboratory (LLNL). This source has an exposure vessel approximately 29.2cm (11.5-inch) tall with an inside diameter of 7.44cm (2.93-inch). Because of the geometry limits, cylindrical symmetry and limited volume, a standard stress relaxation test such as ASTM D 6147-97 could not be utilized and a modified test was developed. An additional constraint imposed by the vertical asymmetry of the <span class="hlt">radiation</span> dose in the exposure chamber was a limited height with reasonably uniform <span class="hlt">radiation</span> exposure. The specific dimensions and <span class="hlt">radiation</span> characteristics of the test cell are in Appendix A.</p> <div class="credits"> <p class="dwt_author">Spellman, G; Gourdin, W; Jensen, W; Pearson, M; Fine, I</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-08-22</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://www.ncbi.nlm.nih.gov/pubmed/24792319"> <span id="translatedtitle">Complementary and alternative medicine in reducing <span class="hlt">radiation-induced</span> skin toxicity.</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-<span class="hlt">induced</span> acute and late effects, particularly skin toxicities, have significant impact on cancer patients' quality of life and long-term survival. To date, no effective topical agents have been routinely used in the clinical setting to prevent skin toxicity. Using SKH-hr1 hairless mice, we investigated two complementary and alternative medicine in their effects on inflammation and ionizing <span class="hlt">radiation</span> (IR)-<span class="hlt">induced</span> skin toxicity: Calendula officinalis (CO) and Ching Wan Hung (CWH). They were applied immediately following each IR dosing of 10 Gy/day for 4 days. Skin toxicity and inflammatory factors were evaluated at multiple time points up to 15 days post-<span class="hlt">radiation</span>. Serum interleukin (IL)-1?, monocyte chemotactic protein-1 (MCP1), keratinocyte-derived chemokine (KC), and granulocyte colony-stimulating factor (G-CSF) were significantly <span class="hlt">induced</span> by <span class="hlt">radiation</span>. Both CO and CWH significantly inhibited IR-<span class="hlt">induced</span> MCP1 (p < 0.01), KC (p < 0.05), and G-CSF (p < 0.001). IR-<span class="hlt">induced</span> erythema and blood vessel dilation were significantly reduced by CWH (p < 0.001) but not by CO at day 10 post-IR. Both agents inhibited IR-<span class="hlt">induced</span> IL-1? (p < 0.01), MCP1 (p < 0.05), and vascular endothelial growth factor (p < 0.05). There were continuous inhibitory effects of CWH on IR-<span class="hlt">induced</span> skin toxicities and inflammation. In contrast, CO treatment resulted in skin reactions compared to IR alone. Our results suggest that both CO and CWH reduce IR-<span class="hlt">induced</span> inflammation and CWH reduced IR-<span class="hlt">induced</span> erythema. In summary, CWH showed promising effects in reducing IR-related inflammation and skin toxicities, and future proof-of-principal testing in humans will be critical in evaluating its potential application in preventing IR-<span class="hlt">induced</span> skin toxicities. PMID:24792319</p> <div class="credits"> <p class="dwt_author">Hu, Jennifer J; Cui, Tengjiao; Rodriguez-Gil, Jorge L; Allen, Glenn O; Li, Jie; Takita, Cristiane; Lally, Brian E</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-08-01</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://ntrs.nasa.gov/search.jsp?R=19730024107&hterms=Solid-state+Physics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3D%2522Solid-state%2BPhysics%2522"> <span id="translatedtitle">Study of interaction among silicon, lithium, oxygen and <span class="hlt">radiation-induced</span> defects for <span class="hlt">radiation</span>-hardened solar cells</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">In order to improve reliability and the useful lifetime of solar cell arrays for space use, a program was undertaken to develop <span class="hlt">radiation</span>-hardened lithium-doped silicon solar cells. These cells were shown to be significantly more resistant to degradation by ionized particles than the presently used n-p nonlithium-doped silicon solar cells. The results of various analyses performed to develop a more complete understanding of the physics of the interaction among lithium, silicon, oxygen, and <span class="hlt">radiation-induced</span> defects are presented. A discussion is given of those portions of the previous model of <span class="hlt">radiation</span> damage annealing which were found to be in error and those portions which were upheld by these extensive investigations.</p> <div class="credits"> <p class="dwt_author">Berman, P. A.</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">359</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/22559204"> <span id="translatedtitle">Spatially fractionated <span class="hlt">radiation</span> <span class="hlt">induces</span> cytotoxicity and changes in gene expression in bystander and <span class="hlt">radiation</span> adjacent murine carcinoma 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"><span class="hlt">Radiation-induced</span> bystander effects have been extensively studied at low doses, since evidence of bystander <span class="hlt">induced</span> cell killing and other effects on unirradiated cells were found to be predominant at doses up to 0.5 Gy. Therefore, few studies have examined bystander effects <span class="hlt">induced</span> by exposure to higher doses of <span class="hlt">radiation</span>, such as spatially fractionated <span class="hlt">radiation</span> (GRID) treatment. In the present study, we evaluate the ability of GRID treatment to <span class="hlt">induce</span> changes in GRID adjacent (bystander) regions, in two different murine carcinoma cell lines following exposure to a single irradiation dose of 10 Gy. Murine SCK mammary carcinoma cells and SCCVII squamous carcinoma cells were irradiated using a brass collimator to create a GRID pattern of nine circular fields 12 mm in diameter with a center-to-center distance of 18 mm. Similar to the typical clinical implementation of GRID, this is approximately a 50:50 ratio of direct and bystander exposure. We also performed experiments by irradiating separate cultures and transferring the medium to unirradiated bystander cultures. Clonogenic survival was evaluated in both cell lines to determine the occurrence of <span class="hlt">radiation-induced</span> bystander effects. For the purpose of our study, we have defined bystander cells as GRID adjacent cells that received approximately 1 Gy scatter dose or unirradiated cells receiving conditioned medium from irradiated cells. We observed significant bystander killing of cells adjacent to the GRID irradiated regions compared to sham treated controls. We also observed bystander killing of SCK and SCCVII cells cultured in conditioned medium obtained from cells irradiated with 10 Gy. Therefore, our results confirm the occurrence of bystander effects following exposure to a high-dose of <span class="hlt">radiation</span> and suggest that cell-to-cell contact is not required for these effects. In addition, the gene expression profile for DNA damage and cellular stress response signaling in SCCVII cells after GRID exposure was studied. The occurrence of GRID-<span class="hlt">induced</span> bystander gene expression changes in significant numbers of DNA damage and cellular stress response signaling genes, providing molecular evidence for possible mechanisms of bystander cell killing. PMID:22559204</p> <div class="credits"> <p class="dwt_author">Asur, Rajalakshmi S; Sharma, Sunil; Chang, Ching-Wei; Penagaricano, Jose; Kommuru, Indira M; Moros, Eduardo G; Corry, Peter M; Griffin, Robert J</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">360</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=3395590"> <span id="translatedtitle">Spatially Fractionated <span class="hlt">Radiation</span> <span class="hlt">Induces</span> Cytotoxicity and Changes in Gene Expression in Bystander and <span class="hlt">Radiation</span> Adjacent Murine Carcinoma 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=pmc">PubMed Central</a></p> <p class="result-summary"><span class="hlt">Radiation-induced</span> bystander effects have been extensively studied at low doses, since evidence of bystander <span class="hlt">induced</span> cell killing and other effects on unirradiated cells were found to be predominant at doses up to 0.5 Gy. Therefore, few studies have examined bystander effects <span class="hlt">induced</span> by exposure to higher doses of <span class="hlt">radiation</span>, such as spatially fractionated <span class="hlt">radiation</span> (GRID) treatment. In the present study, we evaluate the ability of GRID treatment to <span class="hlt">induce</span> changes in GRID adjacent (bystander) regions, in two different murine carcinoma cell lines following exposure to a single irradiation dose of 10 Gy. Murine SCK mammary carcinoma cells and SCCVII squamous carcinoma cells were irradiated using a brass collimator to create a GRID pattern of nine circular fields 12 mm in diameter with a center-to-center distance of 18 mm. Similar to the typical clinical implementation of GRID, this is approximately a 50:50 ratio of direct and bystander exposure. We also performed experiments by irradiating separate cultures and transferring the medium to unirradiated bystander cultures. Clonogenic survival was evaluated in both cell lines to determine the occurrence of <span class="hlt">radiation-induced</span> bystander effects. For the purpose of our study, we have defined bystander cells as GRID adjacent cells that received approximately 1 Gy scatter dose or unirradiated cells receiving conditioned medium from irradiated cells. We observed significant bystander killing of cells adjacent to the GRID irradiated regions compared to sham treated controls. We also observed bystander killing of SCK and SCCVII cells cultured in conditioned medium obtained from cells irradiated with 10 Gy. Therefore, our results confirm the occurrence of bystander effects following exposure to a high-dose of <span class="hlt">radiation</span> and suggest that cell-to-cell contact is not required for these effects. In addition, the gene expression profile for DNA damage and cellular stress response signaling in SCCVII cells after GRID exposure was studied. The occurrence of GRID-<span class="hlt">induced</span> bystander gene expression changes in significant numbers of DNA damage and cellular stress response signaling genes, providing molecular evidence for possible mechanisms of bystander cell killing. PMID:22559204</p> <div class="credits"> <p class="dwt_author">Asur, Rajalakshmi S.; Sharma, Sunil; Chang, Ching-Wei; Penagaricano, Jose; Kommuru, Indira M.; Moros, Eduardo G.; Corry, Peter M.; Griffin, Robert J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</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_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 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<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");' 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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.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4222525"> <span id="translatedtitle"><span class="hlt">Radiation-Induced</span> Apoptosis Varies Among Individuals and is Modified by Sex and Age</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">Purpose Although there are considerable data on mechanisms of <span class="hlt">radiation-induced</span> apoptosis in vitro and in animal models, little is known about functional variation in these pathways in humans. We sought to develop a tractable system to evaluate this. Materials and methods Peripheral blood mononuclear cells were isolated from 90 healthy volunteers, divided into two aliquots, one irradiated with a 5 Gy dose and the other sham-treated (0 Gy), and assessed for damage-<span class="hlt">induced</span> apoptosis after 24 hours. To investigate reproducibility, ten individuals spanning the entire <span class="hlt">radiation-induced</span> apoptotic range were tested three times each, with 3–6 months between replicates. Results We observed surprising heterogeneity in apoptosis among individuals, ranging from 21–62%. Biological replicates from a single individual, however, were completely concordant, suggesting the variability observed across individuals is not the result of stochastic or short-term effects. We found significantly higher <span class="hlt">radiation-induced</span> apoptosis in males than in females (Mean: 41.0% vs. 30.7%; p < 3.5 × 10?7). Moreover, advancing age was associated with decreasing <span class="hlt">radiation-induced</span> apoptosis in males (p = 0.01) but not females (p = 0.82).a Conclusions Our results provide evidence that the function of cellular pathways crucial for stress-<span class="hlt">induced</span> apoptosis varies by sex and could decline with age in humans. PMID:24882388</p> <div class="credits"> <p class="dwt_author">Applebaum, Mark A.; Skol, Andrew D.; Bond, Elisabeth E.; Overholtzer, Michael; Bond, Gareth L.; Onel, Kenan</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</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://academic.research.microsoft.com/Publication/34044050"> <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://academic.research.microsoft.com/">Microsoft Academic Search </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</p> <div class="credits"> <p class="dwt_author">Peter S. Friedmann; Barbara A. Gilchrest</p> <p class="dwt_publisher"></p> <p class="publishDate">1987-01-01</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.hi.helsinki.fi/cgtg/downloads/Nokisalmi_Radiation-induced_upregulation_of_gene_expression_from_adenoviral_vectors_Int_J_Radiat_Oncol_Biol_Phys_2012.pdf"> <span id="translatedtitle">Biology Contribution <span class="hlt">Radiation-Induced</span> Upregulation of Gene Expression From</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">) was studied with and without <span class="hlt">radiation</span> in three cell lines: breast cancer M4A4- LM3, prostate cancer PC-3MM2, Ph.D.,x Laura Ahtiainen, Ph.D.,*,y and Akseli Hemminki, M.D., Ph.D.*,y *Cancer Gene Therapy Group, Molecular Cancer Biology Program, Transplantation Laboratory, Haartman Institute, and Finnish Institute</p> <div class="credits"> <p class="dwt_author">Hemminki, Akseli</p> <p class="dwt_publisher"></p> <p class="publishDate"></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.stanford.edu/group/sherlocklab/pdfs/HELLAND_RADIOTH_ONC_2006.pdf"> <span id="translatedtitle">Molecular radiobiology <span class="hlt">Radiation-induced</span> effects on gene expression</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">the molecular basis underlying response to radiotherapy in breast cancer tissue. Material and Methods: Tumour Background and Purpose: Breast cancer is diagnosed worldwide in approximately one million women annually with breast cancer receiving <span class="hlt">radiation</span> therapy. Gene expression microarray analyses were performed to identify</p> <div class="credits"> <p class="dwt_author">Ford, James</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">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/26327085"> <span id="translatedtitle"><span class="hlt">Radiation</span> <span class="hlt">induced</span> degradation of dyes—An overview</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">Synthetic dyes are a major part of our life. Products ranging from clothes to leather accessories to furniture all depend on extensive use of organic dyes. An unfortunate side effect of extensive use of these chemicals is that huge amounts of these potentially carcinogenic compounds enter our water supplies. Various advanced oxidation processes (AOPs) including the use of high-energy <span class="hlt">radiation</span></p> <div class="credits"> <p class="dwt_author">M. A. Rauf; S. Salman Ashraf</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</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://www.osti.gov/scitech/biblio/1168875"> <span id="translatedtitle">Non-Targeted Effects <span class="hlt">Induced</span> by Ionizing <span class="hlt">Radiation</span>: Mechanisms and Potential Impact on <span class="hlt">Radiation</span> <span class="hlt">Induced</span> Health Effects</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">Not-targeted effects represent a paradigm shift from the "DNA centric" view that ionizing <span class="hlt">radiation</span> only elicits biological effects and subsequent health consequences as a result of an energy deposition event in the cell nucleus. While this is likely true at higher <span class="hlt">radiation</span> doses (> 1Gy), at low doses (< 100mGy) non-targeted effects associated with <span class="hlt">radiation</span> exposure might play a significant role. Here definitions of non-targeted effects are presented, the potential mechanisms for the communication of signals and signaling networks from irradiated cells/tissues are proposed, and the various effects of this intra- and intercellular signaling are described. We conclude with speculation on how these observations might lead to and impact long-term human health outcomes.</p> <div class="credits"> <p class="dwt_author">Morgan, William F.; Sowa, Marianne B.</p> <p class="dwt_publisher"></p> <p class="publishDate">2015-01-01</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://ntrs.nasa.gov/search.jsp?R=19730011000&hterms=helium+spin&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dhelium%2Bspin"> <span id="translatedtitle">Energy Distribution of Electrons in <span class="hlt">Radiation</span> <span class="hlt">Induced</span>-Helium Plasmas. Ph.D. Thesis</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">Energy distribution of high energy electrons as they slow down and thermalize in a gaseous medium is studied. The energy distribution in the entire energy range from source energies down is studied analytically. A helium medium in which primary electrons are created by the passage of heavy-charged particles from nuclear reactions is emphasized. A <span class="hlt">radiation-induced</span> plasma is of interest in a variety of applications, such as <span class="hlt">radiation</span> pumped lasers and gaseous core nuclear reactors.</p> <div class="credits"> <p class="dwt_author">Lo, R. H.</p> <p class="dwt_publisher"></p> <p class="publishDate">1972-01-01</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://academic.research.microsoft.com/Publication/31621301"> <span id="translatedtitle"><span class="hlt">Radiation</span> <span class="hlt">induced</span> G 1-block and p53 status in six human cell lines</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">Considerable attention has recently been focused on the fact that the tumor suppressor protein p53 is involved in the cellular response to <span class="hlt">radiation</span>. In its wild-type form the protein appears to control a cell cycle checkpoint, preventing entry into S-phase following DNA damage. A number of authors observed a <span class="hlt">radiation</span> <span class="hlt">induced</span> G1-block in cells expressing wild-type p53, but not in</p> <div class="credits"> <p class="dwt_author">F. Zölzer; S. Hillebrandt; C. Streffer</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">369</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=3991713"> <span id="translatedtitle">C/EBP? Deficiency Sensitizes Mice to Ionizing <span class="hlt">Radiation-Induced</span> Hematopoietic and Intestinal Injury</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">Knowledge of the mechanisms involved in the <span class="hlt">radiation</span> response is critical for developing interventions to mitigate <span class="hlt">radiation-induced</span> injury to normal tissues. Exposure to <span class="hlt">radiation</span> leads to increased oxidative stress, DNA-damage, genomic instability and inflammation. The transcription factor CCAAT/enhancer binding protein delta (Cebpd; C/EBP? is implicated in regulation of these same processes, but its role in <span class="hlt">radiation</span> response is not known. We investigated the role of C/EBP? in <span class="hlt">radiation-induced</span> hematopoietic and intestinal injury using a Cebpd knockout mouse model. Cebpd?/? mice showed increased lethality at 7.4 and 8.5 Gy total-body irradiation (TBI), compared to Cebpd+/+ mice. Two weeks after a 6 Gy dose of TBI, Cebpd?/? mice showed decreased recovery of white blood cells, neutrophils, platelets, myeloid cells and bone marrow mononuclear cells, decreased colony-forming ability of bone marrow progenitor cells, and increased apoptosis of hematopoietic progenitor and stem cells compared to Cebpd+/+ controls. Cebpd?/? mice exhibited a significant dose-dependent decrease in intestinal crypt survival and in plasma citrulline levels compared to Cebpd+/+ mice after exposure to <span class="hlt">radiation</span>. This was accompanied by significantly decreased expression of ?-H2AX in Cebpd?/? intestinal crypts and villi at 1 h post-TBI, increased mitotic index at 24 h post-TBI, and increase in apoptosis in intestinal crypts and stromal cells of Cebpd?/? compared to Cebpd+/+ mice at 4 h post-irradiation. This study uncovers a novel biological function for C/EBP? in promoting the response to <span class="hlt">radiation-induced</span> DNA-damage and in protecting hematopoietic and intestinal tissues from <span class="hlt">radiation-induced</span> injury. PMID:24747529</p> <div class="credits"> <p class="dwt_author">Chang, Jianhui; Wang, Wenze; Pathak, Rupak; Zhu, Xiaoyan; Wang, Junru; Hendrickson, Howard; Boerma, Marjan; Sterneck, Esta; Zhou, Daohong; Hauer-Jensen, Martin</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</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://adsabs.harvard.edu/abs/1996RaPC...48..201A"> <span id="translatedtitle">On the mechanisms of <span class="hlt">radiation-induced</span> curing of epoxy-fiber composites</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">Depending on the monomer molecular structure, the mechanisms of <span class="hlt">radiation-induced</span> polymerization proceed via either C-centered radical mechanisms or cationic polymerization. While polymerization via C-centered radicals can be impeded by the presence of oxygen and high dose-rate, polymerization through cationic polymerization is inhibited even by the presence of trace amounts of water. Synergy by the combination of <span class="hlt">radiation</span> and thermal curing can help to achieve various desired properties of polymer-fiber composite materials.</p> <div class="credits"> <p class="dwt_author">Al-Sheikhly, Mohamad; McLaughlin, William L.</p> <p class="dwt_publisher"></p> <p class="publishDate">1996-08-01</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.springerlink.com/index/g2n652q2x4hl93g7.pdf"> <span id="translatedtitle">Role of <span class="hlt">Radiation-Induced</span> Signaling Proteins in the Response of Vascular and Connective Tissues</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">\\u000a Over the years considerable effort has been made not only to quantify the tolerance of normal tissue to <span class="hlt">radiation</span>, but also\\u000a to provide a baseline for radiotherapy at maximum biological effective doses. Normal tissue complications <span class="hlt">induced</span> by ionizing\\u000a <span class="hlt">radiation</span> differ depending on the target organ and cell types. Acute or early reactions are primarily characterized by rapidly\\u000a occurring changes within</p> <div class="credits"> <p class="dwt_author">H. P. Rodemann</p> <p class="dwt_publisher"></p> <p class="publishDate"></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://academic.research.microsoft.com/Publication/28846743"> <span id="translatedtitle">Implication of replicative stress-related stem cell ageing in <span class="hlt">radiation-induced</span> murine leukaemia</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">Background:The essential aetiology of <span class="hlt">radiation-induced</span> acute myeloid leukaemia (AML) in mice is the downregulation of the transcription factor PU.1. The causative mutation of the PU.1-endocing Sfpi1 gene consists mostly of C:G to T:A transitions at a CpG site and is likely to be of spontaneous origin. To work out a mechanism underlying the association between <span class="hlt">radiation</span> exposure and the AML</p> <div class="credits"> <p class="dwt_author">N Ban; M Kai</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</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://academic.research.microsoft.com/Publication/51179309"> <span id="translatedtitle">Modeling of Ionizing <span class="hlt">Radiation-Induced</span> Degradation in Multiple Gate Field Effect Transistors</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> response of advanced non-planar mul- tiple gate field effect transistors (MuGFETs) has been shown to have a strong dependence on fin width . The incorporation of total ionizing dose (TID) effects into a physics-based surface-po- tential compact model allows for the effects of <span class="hlt">radiation-induced</span> degradation in MuGFET devices to be modeled in circuit sim- ulators, e.g., SPICE. A</p> <div class="credits"> <p class="dwt_author">Ivan Sanchez Esqueda; Hugh J. Barnaby; Keith E. Holbert; Farah El-Mamouni; Ronald D. Schrimpf</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">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.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3745490"> <span id="translatedtitle">Electrostatic origin of in vitro aggregation of human ?-<span class="hlt">crystallin</span></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">The proteins ?-, ?-, and ?-<span class="hlt">crystallins</span> are the major components of the lens in the human eye. Using dynamic light scattering method, we have performed in vitro investigations of protein-protein interactions in dilute solutions of human ?-<span class="hlt">crystallin</span> and ?-<span class="hlt">crystallin</span>. We find that ?-<span class="hlt">crystallin</span> spontaneously aggregates into finite-sized clusters in phosphate buffer solutions. There are two distinct populations of unaggregated and aggregated ?-<span class="hlt">crystallins</span> in these solutions. On the other hand, ?-<span class="hlt">crystallin</span> molecules are not aggregated into large clusters in solutions of ?-<span class="hlt">crystallin</span> alone. When ?-<span class="hlt">crystallin</span> and ?-<span class="hlt">crystallin</span> are mixed in phosphate buffer solutions, we demonstrate that the clusters of ?-<span class="hlt">crystallin</span> are prevented. By further investigating the roles of temperature, protein concentration, pH, salt concentration, and a reducing agent, we show that the aggregation of ?-<span class="hlt">crystallin</span> under our in vitro conditions arises from non-covalent electrostatic interactions. In addition, we show that aggregation of ?-<span class="hlt">crystallin</span> occurs under the dilute in vitro conditions even in the absence of oxidizing agents that can <span class="hlt">induce</span> disulfide cross-links, long considered to be responsible for human cataracts. Aggregation of ?-<span class="hlt">crystallin</span> when maintained under reducing conditions suggests that oxidation does not contribute to the aggregation in dilute solutions. PMID:24089726</p> <div class="credits"> <p class="dwt_author">Mohr, Benjamin G.; Dobson, Cassidy M.; Garman, Scott C.; Muthukumar, Murugappan</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</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://www.ncbi.nlm.nih.gov/pubmed/19408841"> <span id="translatedtitle">Use of probiotics for prevention of <span class="hlt">radiation-induced</span> diarrhea.</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">Probiotics can be applied in therapy and mainly in prevention of many civilization disorders. Experimental studies in animal models and clinical trials of patients with inflammatory bowel disease (IBD) have consistently shown that the use of probiotic organisms may effectively down-modulate the severity of intestinal inflammation by altering the composition and metabolic and functional properties of indigenous flora of the gut. Previous studies showed a protective effect of probiotic administration after <span class="hlt">radiation</span> therapy, and probiotic may play an important role in the pathogenesis of <span class="hlt">radiation</span> enteropathy. These studies indicate that probiotics may decrease the risk of accumulated reactive oxygen species (ROS) in host organisms and could potentially be used as probiotic food supplements to reduce oxidative stress (Tab. 2, Ref. 47). Full Text (Free, PDF) www.bmj.sk. PMID:19408841</p> <div class="credits"> <p class="dwt_author">Blanarova, C; Galovicova, A; Petrasova, D</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</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://academic.research.microsoft.com/Publication/37087549"> <span id="translatedtitle">Molecular mechanisms of ionizing <span class="hlt">radiation-induced</span> apoptosis</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> activates not only signalling pathways in the nucleus as a result of DNA damage, but also signalling pathways initiated at the level of the plasma membrane. Proteins involved in DNA damage recognition include poly(ADP ribose) polymerase (PARP), DNA-dependent protein kinase, p53 and ataxia- telangiectasia mutated (ATM). Many of these proteins are inactivated by caspases during the execution phase</p> <div class="credits"> <p class="dwt_author">Dianne Watters</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">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.cancer.gov/clinicaltrials/featured/trials/MAYO-MCS285"> <span id="translatedtitle">Electroacupuncture for <span class="hlt">Radiation-Induced</span> Chronic Dry Mouth</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.cancer.gov">Cancer.gov</a></p> <p class="result-summary">In this clinical trial, head and neck cancer patients with chronic dry mouth who completed <span class="hlt">radiation</span> therapy at least 6 months before joining the trial and who received no benefit from treatment with the drug pilocarpine (Salagen) will be randomly assigned to undergo electroacupuncture using a machine called a LISS stimulator, or a sham procedure, using a similar-looking machine that does not produce electrical stimulation.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></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=243757"> <span id="translatedtitle">Solar <span class="hlt">radiation</span> <span class="hlt">induces</span> sublethal injury in Escherichia coli in seawater.</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">Sublethal injury was noted in Escherichia coli after cells were exposed to solar <span class="hlt">radiation</span>. Injury was detected by differential plate counts between complete and minimal media that were observed with sunlight-exposed cells but not with cells kept in the dark. Since addition of catalase or pyruvate to minimal medium overcame or repaired this injury, the catalase system appeared to be the site of injury. PMID:7013708</p> <div class="credits"> <p class="dwt_author">Kapuscinski, R B; Mitchell, R</p> <p class="dwt_publisher"></p> <p class="publishDate">1981-01-01</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://academic.research.microsoft.com/Publication/47773191"> <span id="translatedtitle">Management of <span class="hlt">Radiation-Induced</span> Head and Neck Injury</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">During the treatment of neoplastic diseases, unavoidable toxicities to normal cells may be produced. The mucosal lining of\\u000a the upper respiratory and gastrointestinal tracts is a prime target for radiotherapy-related toxicity due to its rapid cell\\u000a turnover rate. The oral cavity is highly sensitive to direct and indirect toxic effects of <span class="hlt">radiation</span> therapy (RT); this is\\u000a attributable to multiple factors</p> <div class="credits"> <p class="dwt_author">Angel I. Blanco; Clifford Chao</p> <p class="dwt_publisher"></p> <p class="publishDate"></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://www.ncbi.nlm.nih.gov/pubmed/23042190"> <span id="translatedtitle"><span class="hlt">Radiation</span> combined with thermal injury <span class="hlt">induces</span> immature myeloid 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">The continued development of nuclear weapons and the potential for thermonuclear injury necessitates the further understanding of the immune consequences after <span class="hlt">radiation</span> combined with injury (RCI). We hypothesized that sublethal ionization <span class="hlt">radiation</span> exposure combined with a full-thickness thermal injury would result in the production of immature myeloid cells. Mice underwent either a full-thickness contact burn of 20% total body surface area or sham procedure followed by a single whole-body dose of 5-Gy <span class="hlt">radiation</span>. Serum, spleen, and peripheral lymph nodes were harvested at 3 and 14 days after injury. Flow cytometry was performed to identify and characterize adaptive and innate cell compartments. Elevated proinflammatory and anti-inflammatory serum cytokines and profound leukopenia were observed after RCI. A population of cells with dual expression of the cell surface markers Gr-1 and CD11b were identified in all experimental groups, but were significantly elevated after burn alone and RCI at 14 days after injury. In contrast to the T-cell-suppressive nature of myeloid-derived suppressor cells found after trauma and sepsis, myeloid cells after RCI augmented T-cell proliferation and were associated with a weak but significant increase in interferon ? and a decrease in interleukin 10. This is consistent with previous work in burn injury indicating that a myeloid-derived suppressor cell-like population increases innate immunity. <span class="hlt">Radiation</span> combined injury results in the increase in distinct populations of Gr-1CD11b cells within the secondary lymphoid organs, and we propose these immature inflammatory myeloid cells provide innate immunity to the severely injured and immunocompromised host. PMID:23042190</p> <div class="credits"> <p class="dwt_author">Mendoza, April Elizabeth; Neely, Crystal Judith; Charles, Anthony G; Kartchner, Laurel Briane; Brickey, Willie June; Khoury, Amal Lina; Sempowski, Gregory D; Ting, Jenny P Y; Cairns, Bruce A; Maile, Robert</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-11-01</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" 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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://www.ncbi.nlm.nih.gov/pubmed/25360944"> <span id="translatedtitle">Dispersive <span class="hlt">radiation</span> <span class="hlt">induced</span> by shock waves in passive resonators.</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 show that passive Kerr resonators pumped close to zero dispersion wavelengths on the normal dispersion side can develop the resonant generation of linear waves driven by cavity (mixed dispersive-dissipative) shock waves. The resonance mechanism can be successfully described in the framework of the generalized Lugiato-Lefever equation with higher-order dispersive terms. Substantial differences with <span class="hlt">radiation</span> from cavity solitons and purely dispersive shock waves dispersion are highlighted. PMID:25360944</p> <div class="credits"> <p class="dwt_author">Malaguti, Stefania; Conforti, Matteo; Trillo, Stefano</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-10-01</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.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3796387"> <span id="translatedtitle">Protective effect of tanshinone IIA against <span class="hlt">radiation-induced</span> ototoxicity in HEI-OC1 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=pmc">PubMed Central</a></p> <p class="result-summary">Radiotherapy is a highly efficient treatment method for nasopharyngeal carcinoma that is often accompanied by significant ototoxic side-effects. The inner ear hair cells are particularly prone to serious injury following radiotherapy. Tanshinone IIA is a transcription factor inhibitor that is extracted from the traditional herbal medicine, Salvia miltiorrhiza Bunge. The present study investigated the effects of tanshinone IIA treatment on <span class="hlt">radiation-induced</span> toxicity in the HEI-OC1 hair cell line. Using an MTT assay and flow cytometry, the <span class="hlt">radiation-induced</span> weakening of the cells was observed to be alleviated when the cells were pre-treated with tanshinone IIA. <span class="hlt">Radiation</span> exposure promoted p65/nuclear factor (NF)-?B nuclear translocation and activated the p53/p21 pathway, two processes which play a significant role in <span class="hlt">radiation-induced</span> cell apoptosis. However, pre-treatment of the cells with tanshinone IIA inhibited p65/NF-?B nuclear translocation and p53/p21 pathway activation. These results demonstrate that tanshinone IIA is capable of protecting cochlear cells from <span class="hlt">radiation-induced</span> injury through the suppression of p65/NF-?B nuclear translocation and the p53/p21 signaling pathway. PMID:24137434</p> <div class="credits"> <p class="dwt_author">DU, SHASHA; YAO, QIWEI; TAN, PEIXIN; XIE, GUOZHU; REN, CHEN; SUN, QUANQUAN; ZHANG, XIAO; ZHENG, RONG; YANG, KAIJUN; YUAN, YAWEI; YUAN, QUAN</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</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://www.ncbi.nlm.nih.gov/pubmed/24880906"> <span id="translatedtitle">Imaging of nuclear factor ?B activation <span class="hlt">induced</span> by ionizing <span class="hlt">radiation</span> in human embryonic kidney (HEK) 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> modulates several signaling pathways resulting in transcription factor activation. Nuclear factor kappa B (NF-?B) is one of the most important transcription factors that respond to changes in the environment of a mammalian cell. NF-?B plays a key role not only in inflammation and immune regulation but also in cellular <span class="hlt">radiation</span> response. In response to DNA damage, NF-?B might inhibit apoptosis and promote carcinogenesis. Our previous studies showed that ionizing <span class="hlt">radiation</span> is very effective in <span class="hlt">inducing</span> biological damages. Therefore, it is important to understand the <span class="hlt">radiation-induced</span> NF-?B signaling cascade. The current study aims to improve existing mammalian cell-based reporter assays for NF-?B activation by the use of DD-tdTomato which is a destabilized variant of red fluorescent protein tdTomato. It is demonstrated that exposure of recombinant human embryonic kidney cells (HEK/293 transfected with a reporter constructs containing NF-?B binding sites in its promoter) to ionizing <span class="hlt">radiation</span> <span class="hlt">induces</span> NF-?B-dependent DD-tdTomato expression. Using this reporter assays, NF-?B signaling in mammalian cells was monitored by flow cytometry and fluorescence microscopy. Activation of NF-?B by the canonical pathway was found to be quicker than by the genotoxin- and stress-<span class="hlt">induced</span> pathway. X-rays activate NF-?B in HEK cells in a dose-dependent manner, and the extent of NF-?B activation is higher as compared to camptothecin. PMID:24880906</p> <div class="credits"> <p class="dwt_author">Chishti, Arif Ali; Baumstark-Khan, Christa; Hellweg, Christine E; Reitz, Günther</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-08-01</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://ntrs.nasa.gov/search.jsp?R=20040112350&hterms=Breast+cancer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3D%2528Breast%2Bcancer%2529"> <span id="translatedtitle"><span class="hlt">Radiation</span> <span class="hlt">induces</span> genomic instability and mammary ductal dysplasia in Atm heterozygous mice</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">Ataxia-telangiectasia (AT) is a genetic syndrome resulting from the inheritance of two defective copies of the ATM gene that includes among its stigmata radiosensitivity and cancer susceptibility. Epidemiological studies have demonstrated that although women with a single defective copy of ATM (AT heterozygotes) appear clinically normal, they may never the less have an increased relative risk of developing breast cancer. Whether they are at increased risk for <span class="hlt">radiation-induced</span> breast cancer from medical exposures to ionizing <span class="hlt">radiation</span> is unknown. We have used a murine model of AT to investigate the effect of a single defective Atm allele, the murine homologue of ATM, on the susceptibility of mammary epithelial cells to <span class="hlt">radiation-induced</span> transformation. Here we report that mammary epithelial cells from irradiated mice with one copy of Atm truncated in the PI-3 kinase domain were susceptible to <span class="hlt">radiation-induced</span> genomic instability and generated a 10% incidence of dysplastic mammary ducts when transplanted into syngenic recipients, whereas cells from Atm(+/+) mice were stable and formed only normal ducts. Since <span class="hlt">radiation-induced</span> ductal dysplasia is a precursor to mammary cancer, the results indicate that AT heterozygosity increases susceptibility to radiogenic breast cancer in this murine model system.</p> <div class="credits"> <p class="dwt_author">Weil, M. M.; Kittrell, F. S.; Yu, Y.; McCarthy, M.; Zabriskie, R. C.; Ullrich, R. L.</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</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://adsabs.harvard.edu/abs/2009PCM....36..291F"> <span id="translatedtitle"><span class="hlt">Induced</span> modifications of kaolinite under ionizing <span class="hlt">radiation</span>: an infrared spectroscopic study</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</span> effects on kaolinite were investigated using He+ ions of 1.5 MeV at <span class="hlt">radiation</span> doses up to 4.3 × 108 Gy, which are comparable to the doses expected for clay barriers in high-level nuclear waste repositories. The concentration of paramagnetic <span class="hlt">radiation-induced</span> defects in kaolinite reaches 2 × 1016 spins/mg (400 at. ppm), as determined by electron paramagnetic resonance spectroscopy. The broadening of X-ray diffraction patterns and transmission infrared (IR) absorption bands is mostly related to the structural strain <span class="hlt">induced</span> by <span class="hlt">radiation-induced</span> point defects. The broadening of IR absorption spectra is analyzed using an autocorrelation approach and is related to a change in the distribution of vibrational frequencies due to crystal heterogeneities. We theoretically analyze how the effective dielectric properties of kaolinite samples depend on macroscopic parameters and how irradiation can modify some of them. Irradiation leads to an increase in the electronic polarizability of kaolinite particles, related to the accumulation of <span class="hlt">radiation-induced</span> electronic point defects.</p> <div class="credits"> <p class="dwt_author">Fourdrin, C.; Balan, E.; Allard, T.; Boukari, C.; Calas, G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-05-01</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/6605110"> <span id="translatedtitle"><span class="hlt">Radiation-induced</span> proctitis cystica profunda in the rat</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">Therapeutic pelvic irradiation is notorious for the production of clinically significant sequela after a long latency. One of the rarest of these complications is proctitis cystica profunda (PCP). To study the histologic changes of chronic <span class="hlt">radiation</span> proctitis, we evaluated 35 female Wistar rats that had received a single exposure of 22.5 Gy of <span class="hlt">radiation</span> to the rectum and were then followed for one year. We identified PCP and its precursor lesions in 18 rats. The fully developed lesion consisted of a focal expansion of the submucosa by dilated cystic spaces lined by a single layer of benign epithelial cells. Usually, PCP evolved as glands herniated between small defects in the muscularis mucosae. Mitotic figures were not recognized in the cells lining the herniating glands. In two rats, the <span class="hlt">radiation</span> had apparently caused large ulcers, which had subsequently reepithelialized, resulting in prominent submucosal glandular tissue. Although the number of goblet cells in the displaced epithelium was reduced, the cells had rather mature appearances ultrastructurally. Glands displaced into the submucosa were encased by an intact basal lamina but lacked in muscularis.</p> <div class="credits"> <p class="dwt_author">Geisinger, K.R.; Scobey, M.W.; Northway, M.G.; Cassidy, K.T.; Castell, D.O. (Wake Forest Univ., Winston-Salem, NC (USA))</p> <p class="dwt_publisher"></p> <p class="publishDate">1990-07-01</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://adsabs.harvard.edu/abs/2003AdSpR..31..119S"> <span id="translatedtitle">Cognitive deficits <span class="hlt">induced</span> by 56Fe <span class="hlt">radiation</span> exposure</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">Exposing rats to particles of high energy and charge (e.g., 56Fe) disrupts neuronal systems and the behaviors mediated by them; these adverse behavioral and neuronal effects are similar to those seen in aged animals. Because cognition declines with age, and our previous study showed that <span class="hlt">radiation</span> disrupted Morris water maze spatial learning and memory performance, the present study used an 8-arm radial maze (RAM) to further test the cognitive behavioral consequences of <span class="hlt">radiation</span> exposure. Control rats or rats exposed to whole-body irradiation with 1.0 Gy of 1 GeV/n high-energy 56Fe particles (delivered at the alternating gradient synchrotron at Brookhaven National Laboratory) were tested nine months following exposure. <span class="hlt">Radiation</span> adversely affected RAM performance, and the changes seen parallel those of aging. Irradiated animals entered baited arms during the first 4 choices significantly less than did controls, produced their first error sooner, and also tended to make more errors as measured by re-entries into non-baited arms. These results show that irradiation with high-energy particles produces age-like decrements in cognitive behavior that may impair the ability of astronauts to perform critical tasks during long-term space travel beyond the magnetosphere.</p> <div class="credits"> <p class="dwt_author">Shukitt-Hale, B.; Casadesus, G.; Cantuti-Castelvetri, I.; Rabin, B. M.; Joseph, J. A.</p> <p class="dwt_publisher"></p> <p class="publishDate"></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://ntrs.nasa.gov/search.jsp?R=20040087860&hterms=animal+behavior&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Danimal%2Bbehavior"> <span id="translatedtitle">Cognitive deficits <span class="hlt">induced</span> by 56Fe <span class="hlt">radiation</span> exposure</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">Exposing rats to particles of high energy and charge (e.g., 56Fe) disrupts neuronal systems and the behaviors mediated by them; these adverse behavioral and neuronal effects are similar to those seen in aged animals. Because cognition declines with age, and our previous study showed that <span class="hlt">radiation</span> disrupted Morris water maze spatial learning and memory performance, the present study used an 8-arm radial maze (RAM) to further test the cognitive behavioral consequences of <span class="hlt">radiation</span> exposure. Control rats or rats exposed to whole-body irradiation with 1.0 Gy of 1 GeV/n high-energy 56Fe particles (delivered at the alternating gradient synchrotron at Brookhaven National Laboratory) were tested nine months following exposure. <span class="hlt">Radiation</span> adversely affected RAM performance, and the changes seen parallel those of aging. Irradiated animals entered baited arms during the first 4 choices significantly less than did controls, produced their first error sooner, and also tended to make more errors as measured by re-entries into non-baited arms. These results show that irradiation with high-energy particles produces age-like decrements in cognitive behavior that may impair the ability of astronauts to perform critical tasks during long-term space travel beyond the magnetosphere. Published by Elsevier Science Ltd on behalf of COSPAR.</p> <div class="credits"> <p class="dwt_author">Shukitt-Hale, B.; Casadesus, G.; Cantuti-Castelvetri, I.; Rabin, B. M.; Joseph, J. A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</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://www.ncbi.nlm.nih.gov/pubmed/25436137"> <span id="translatedtitle">Regorafenib-<span class="hlt">induced</span> transverse myelopathy after stereotactic body <span class="hlt">radiation</span> therapy.</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">Stereotactic body <span class="hlt">radiation</span> therapy (SBRT) delivers large doses of <span class="hlt">radiation</span> with great accuracy, but is known to have deleterious effects on the vascular compartment of irradiated tissues. Combining SBRT with targeted anti-angiogenesis agents, while able to increase therapeutic efficacy, may unexpectedly precipitate vascular-based toxicities. In this report, we describe a patient with colon cancer who developed transverse myelopathy from regorafenib 2 years after receiving SBRT for three metastatic liver lesions. Regorafenib (Stivarga), formerly BAY 73-4506, (Bayer HealthCare Pharmaceuticals, Montville, NJ) is a multiple receptor tyrosine kinase inhibitor with anti-angiogenic effects used in metastatic colon cancer. Its most common side effects are fatigue, diarrhea and hypertension. However, severe neurologic toxicity has not been previously recognized. Here, we illustrate a case in which the patient developed hyperalgesia and radicular pain 2 weeks after starting regorafenib. Several studies report an increased neurological toxicity when angiogenesis inhibitors are given after <span class="hlt">radiation</span> therapy, and we postulate that the angioinhibitory effects of regorafenib accelerated subclinical microvascular injury from SBRT. This unexpected toxicity may be clinically relevant when giving targeted angiogenesis inhibitors after SBRT. PMID:25436137</p> <div class="credits"> <p class="dwt_author">Tian, Sibo; Nissenblatt, Michael; Goyal, Sharad</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-12-01</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://ntrs.nasa.gov/search.jsp?R=20040087883&hterms=epigenetic&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Depigenetic"> <span id="translatedtitle">Characterization of a novel epigenetic effect of ionizing <span class="hlt">radiation</span>: the death-<span class="hlt">inducing</span> effect</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">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 challenged this dogma. After cellular exposure to ionizing <span class="hlt">radiation</span>, we have isolated a number of clones of Chinese hamster-human hybrid GM10115 cells that demonstrate genomic instability as measured by chromosomal destabilization. These clones show dynamic and persistent generation of chromosomal rearrangements multiple generations after the original insult. We hypothesize that these unstable clones maintain this delayed instability phenotype by secreting factors into the culture medium. To test this hypothesis we transferred filtered medium from unstable cells to unirradiated GM10115 cells. No GM10115 cells were able to survive this medium. This phenomenon by which GM10115 cells die when cultured in medium from chromosomally unstable GM10115 clones is the death-<span class="hlt">inducing</span> effect. Medium transfer experiments indicate that a factor or factors is/are secreted by unstable cells within 8 h of growth in fresh medium and result in cell killing within 24 h. These factors are stable at ambient temperature but do not survive heating or freezing, and are biologically active when diluted with fresh medium. We present the initial description and characterization of the death-<span class="hlt">inducing</span> effect. This novel epigenetic effect of <span class="hlt">radiation</span> has implications for <span class="hlt">radiation</span> risk assessment and for health risks associated with <span class="hlt">radiation</span> exposure.</p> <div class="credits"> <p class="dwt_author">Nagar, Shruti; Smith, Leslie E.; Morgan, William F.</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</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.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4136475"> <span id="translatedtitle">PHD Inhibition Mitigates and Protects Against <span class="hlt">Radiation-Induced</span> Gastrointestinal Toxicity via HIF2</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"><span class="hlt">Radiation-induced</span> gastrointestinal (GI) toxicity can be a major source of morbidity and mortality after <span class="hlt">radiation</span> exposure. There is an unmet need for effective preventative or mitigative treatments against the potentially fatal diarrhea and water loss <span class="hlt">induced</span> by <span class="hlt">radiation</span> damage to the GI tract. We report that prolyl hydroxylase inhibition by genetic knockout or pharmacologic inhibition of all PHD isoforms by the small molecule dimethyloxyallylglycine (DMOG) increases HIF expression, improves epithelial integrity, reduces apoptosis, and increases intestinal angiogenesis, all of which are essential for radioprotection. HIF2, but not HIF1, is both necessary and sufficient to prevent <span class="hlt">radiation-induced</span> GI toxicity and death. Increased VEGF expression contributes to the protective effects of HIF2, since inhibition of VEGF function reversed the radioprotection and radiomitigation afforded by DMOG. Additionally, mortality is reduced from abdominal or total body irradiation even when DMOG is given 24 hours after exposure. Thus, prolyl hydroxylase inhibition represents a new treatment strategy to protect against and mitigate GI toxicity from both therapeutic <span class="hlt">radiation</span> and potentially lethal <span class="hlt">radiation</span> exposures. PMID:24828078</p> <div class="credits"> <p class="dwt_author">Taniguchi, Cullen M.; Miao, Yu Rebecca; Diep, Anh N.; Wu, Colleen; Rankin, Erinn B.; Atwood, Todd F.; Xing, Lei; Giaccia, Amato J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</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/5933677"> <span id="translatedtitle">Total-dose <span class="hlt">radiation-induced</span> degradation of thin film ferroelectric capacitors</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">Thin film PbZr{sub y}Ti{sub 1{minus}y}O{sub 3} (PZT) ferroelectric memories offer the potential for <span class="hlt">radiation</span>-hardened, high-speed nonvolatile memories with good retention and fatigue properties. In this paper we explore in detail the <span class="hlt">radiation</span> hardness of PZT ferroelectric capacitors. Ferroelectric capacitors were irradiated using x-ray and Co-60 sources to dose levels up to 16 Mrad(Si). The capacitors were characterized for their memory properties both before and after irradiation. The <span class="hlt">radiation</span> hardness was process dependent. Three out of four processes resulted in capacitors that showed less than 30% <span class="hlt">radiation-induced</span> degradation in retained polarization charge and remanent polarization after irradiating to 16 Mrad(Si). On the other hand, one of the processes showed significant <span class="hlt">radiation-induced</span> degradation in retained polarization charge and remanent polarization at dose levels above 1 Mrad(Si). The decrease in retained polarization charge appears to be due to an alteration of the switching characteristics of the ferroelectric due to changes in the internal fields. The <span class="hlt">radiation-induced</span> degradation is recoverable by a postirradiation biased anneal and can be prevented entirely if devices are cycled during irradiation. The authors have developed a model to simulate the observed degradation.</p> <div class="credits"> <p class="dwt_author">Schwank, J.R.; Nasby, R.D.; Miller, S.L.; Rodgers, M.S.; Dressendorfer, P.V. (Sandia National Labs., Albuquerque, NM (USA))</p> <p class="dwt_publisher"></p> <p class="publishDate">1990-12-01</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/20211636"> <span id="translatedtitle">Three-dimensional culture conditions lead to decreased <span class="hlt">radiation</span> <span class="hlt">induced</span> cytotoxicity in human mammary epithelial 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">For both targeted and non-targeted exposures, the cellular responses to ionizing <span class="hlt">radiation</span> have predominantly been measured in two-dimensional monolayer cultures. Although convenient for biochemical analysis, the true interactions in vivo depend upon complex interactions between cells themselves and the surrounding extracellular matrix. This study directly compares the influence of culture conditions on <span class="hlt">radiation</span> <span class="hlt">induced</span> cytotoxicity following exposure to low-LET ionizing <span class="hlt">radiation</span>. Using a three-dimensional (3D) human mammary epithelial tissue model, we have found a protective effect of 3D cell culture on cell survival after irradiation. The initial state of the cells (i.e., 2D versus 3D culture) at the time of irradiation does not alter survival, nor does the presence of extracellular matrix during and after exposure to dose, but long term culture in 3D which offers significant reduction in cytotoxicity at a given dose (e.g. approximately 4-fold increased survival at 5Gy). The cell cycle delay <span class="hlt">induced</span> following exposure to 2 and 5Gy was almost identical between 2D and 3D culture conditions and cannot account for the observed differences in <span class="hlt">radiation</span> responses. However the amount of apoptosis following <span class="hlt">radiation</span> exposure is significantly decreased in 3D culture relative to the 2D monolayer after the same dose. A likely mechanism of the cytoprotective effect afforded by 3D culture conditions is the down regulation of <span class="hlt">radiation</span> <span class="hlt">induced</span> apoptosis in 3D structures. PMID:20211636</p> <div class="credits"> <p class="dwt_author">Sowa, Marianne B; Chrisler, William B; Zens, Kyra D; Ashjian, Emily J; Opresko, Lee K</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-05-01</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://www.osti.gov/scitech/biblio/991997"> <span id="translatedtitle">Three-dimensional Culture Conditions Lead to Decreased <span class="hlt">Radiation</span> <span class="hlt">Induced</span> Crytoxicity in Human Mammary Epithelial Cells</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">For both targeted and non-targeted exposures, the cellular responses to ionizing <span class="hlt">radiation</span> have predominantly been measured in two dimensional monolayer cultures. Although convenient for biochemical analysis, the true interactions in vivo depend upon complex interactions between cells themselves and the surrounding extra cellular matrix. This study directly compares the influence of culture conditions on <span class="hlt">radiation</span> <span class="hlt">induced</span> cytotoxicity following exposure to low-LET ionizing <span class="hlt">radiation</span>. Using a three dimensional (3D) human mammary epithelial tissue model, we have found a protective effect of 3D cell culture on cell survival after irradiation. The initial state of the cells (i.e., 2D vs. 3D culture) at the time of irradiation does not alter survival, nor does the presence of extracellular matrix during and after exposure to dose, but long term culture in 3D which offers significant reduction in cytotoxicity at a given dose (e.g. ~4 fold increased survival at 5 Gy). The cell cycle delay <span class="hlt">induced</span> following exposure to 2 and 5 Gy was almost identical between 2D and 3D culture conditions and cannot account for the observed differences in <span class="hlt">radiation</span> responses. However the amount of apoptosis following <span class="hlt">radiation</span> exposure is significantly decreased in 3D culture relative to the 2D monolayer after the same dose. A likely mechanism of the cytoprotective effect afforded by 3D culture conditions is the down regulation of <span class="hlt">radiation</span> <span class="hlt">induced</span> apoptosis in 3D structures</p> <div class="credits"> <p class="dwt_author">Sowa, Marianne B.; Chrisler, William B.; Zens, Kyra D.; Ashjian, Emily J.; Opresko, Lee K.</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-05-01</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://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2477724"> <span id="translatedtitle">Non-Problematic Risks from Low-Dose <span class="hlt">Radiation-Induced</span> DNA Damage Clusters</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"><span class="hlt">Radiation-induced</span> DNA damage clusters have been proposed and are usually considered to pose the threat of serious biological damage. This has been attributed to DNA repair debilitation or cessation arising from the complexity of cluster damage. It will be shown here, contrary to both previous suggestions and perceived wisdom, that <span class="hlt">radiation</span> <span class="hlt">induced</span> damage clusters contribute to non-problematic risks in the low-dose, low-LET regime. The very complexity of cluster damage which inhibits and/or compromises DNA repair will ultimately be responsible for the elimination and/or diminution of precancer-ous and cancerous cells. PMID:18648573</p> <div class="credits"> <p class="dwt_author">Hayes, Daniel P.</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</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://adsabs.harvard.edu/abs/2013RaPC...84..242A"> <span id="translatedtitle">Antimicrobial fabric adsorbed iodine produced by <span class="hlt">radiation-induced</span> graft polymerization</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">Antimicrobial fabric was synthesized by <span class="hlt">radiation-induced</span> graft polymerization of N-vinyl pyrrolidone onto polyolefine nonwoven fabric and subsequent adsorption of iodine. In response of the huge request for the antimicrobial material applied to face masks for swine flu in 2009, operation procedure of continuous <span class="hlt">radiation-induced</span> graft polymerization apparatus was improved. The improved grafting production per week increased 3.8 times compared to the production by former operation procedure. Shipped antimicrobial fabric had reached 130,000 m2 from June until December, 2009.</p> <div class="credits"> <p class="dwt_author">Aoki, Shoji; Fujiwara, Kunio; Sugo, Takanobu; Suzuki, Koichi</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">397</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/10107117"> <span id="translatedtitle">Transient <span class="hlt">radiation-induced</span> absorption in materials for the DOI laser</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 is the final report on a series of experiments concerned with transient <span class="hlt">radiation-induced</span> absorption in materials for a Cr,Nd:GSGG laser. Both the Sandia National Laboratories SPR III pulsed reactor and the Hermes III pulsed X-ray machine are used as <span class="hlt">radiation</span> sources. The time dependence and the magnitude of the <span class="hlt">induced</span> absorption in filter glasses and in doped and undoped LiNbO{sub 3} Q-switch materials have been measured. Gain has been observed in Cr,Nd:GSGG, the laser medium, when it is irradiated by X-rays.</p> <div class="credits"> <p class="dwt_author">Brannon, P.J.</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">398</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/5663407"> <span id="translatedtitle">Comparative analysis of <span class="hlt">radiation</span>- and virus-<span class="hlt">induced</span> leukemias in BALB/c mice</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">Endogenous murine leukemia virus (MuLV) proviral copies were analyzed in thymomas <span class="hlt">induced</span> in normal BALB/c (Fv-1b) and in Fv-1n congenic mice by X-irradiation. Both strains of mice developed leukemia with similar kinetics, indicating that N-tropism of endogenous MuLV was not a rate-limiting factor in development of disease. Southern blot analysis, using a probe specific for ecotropic virus and for ecotropic-specific sequences retained in pathogenic, env-recombinant viruses, showed that the majority of <span class="hlt">radiation</span> leukemias lacked newly acquired, clonally integrated, proviruses. This was in contrast to virus-<span class="hlt">induced</span> leukemias, which routinely exhibited several new proviral integration sites. When an internal proviral DNA restriction fragment was monitored, some <span class="hlt">radiation</span> leukemias showed evidence of nonclonal infection, accounting for more frequent isolation of infectious virus from such leukemias. Differences in expression of T-cell surface antigens were found in X-ray-<span class="hlt">induced</span> and virus-<span class="hlt">induced</span> leukemias. All <span class="hlt">radiation</span> leukemias were TL positive, whereas virus-<span class="hlt">induced</span> leukemias were primarily negative for TL. Some differences were also found in Lyt-1 and Lyt-2 expression. The data as a whole suggest that, in the majority of cases, <span class="hlt">radiation</span> leukemogenesis is not initiated by a viral route--that is, the sort of viral mechanism for which exogenous infection by known pathogenic MuLV is the paradigm.</p> <div class="credits"> <p class="dwt_author">Newcomb, E.W.; Binari, R.; Fleissner, E.</p> <p class="dwt_publisher"></p> <p class="publishDate">1985-01-15</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/biblio/5019066"> <span id="translatedtitle"><span class="hlt">Radiation-induced</span> chromosomal inversions in mice. Technical progress report</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">Chromosomal inversions are being produced for the purpose of establishing efficient systems for assessing <span class="hlt">induced</span> and spontaneous heritable mutations. The inversions and other chromosomal aberrations produced are used to ask basic questions about meiosis and reproductive performance. Chromosomal structure is being studied by identifying the cytological location of genes and break points related to the inversions. 2 tabs.</p> <div class="credits"> <p class="dwt_author">Roderick, T.H.</p> <p class="dwt_publisher"></p> <p class="publishDate">1986-01-01</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/49962459"> <span id="translatedtitle"><span class="hlt">Radiation-induced</span> dark current increases in CCDs</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 on ionization and displacement damage-<span class="hlt">induced</span> dark current increases in CCDs. Effects of reverse annealing and operation in surface inversion (dither clocking and MPP mode) are discussed. Bulk damage effects such as field enhancement and random telegraph noise are also considered. The emphasis is on effects in the near-Earth space environment</p> <div class="credits"> <p class="dwt_author">G. R. Hopkinson; Kent BR</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-01-01</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 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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://adsabs.harvard.edu/abs/1999NIMPB.151..399K"> <span id="translatedtitle">Modification of poly(vinyltrimethylsilane) by <span class="hlt">radiation-induced</span> graft polymerization</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 modification of polyvinyltrimethylsilane (PVTMS) has been carried out using the <span class="hlt">radiation-induced</span> graft polymerization. PVTMS is applied as a basis for gas-separating membranes. Acrylonitrile, acrolein, ethyl acrylate, acrylic acid and acrylamide were used as monomers. The grafting was performed both from vapour and liquid phase of monomers and their solutions by the direct <span class="hlt">radiation</span> method. Some kinetic regularities of <span class="hlt">radiation</span> graft polymerization of monomers and the character of distribution of grafted polymers along the thickness of PVTMS films were studied. It was shown that grafting improves the chemical resistance, the selective permeability of gases and some mechanical properties of PVTMS films.</p> <div class="credits"> <p class="dwt_author">Kudryavtsev, Val. N.; Starannikova, L. E.; Teplyakov, V. V.; Kabanov, V. Ya.</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-05-01</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://www.osti.gov/scitech/biblio/6425918"> <span id="translatedtitle">The response of kidney to ionizing <span class="hlt">radiation</span> combined with hyperthermia <span class="hlt">induced</span> by ultrasound</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">Mouse kidneys were made hyperthermic (42.5/sup 0/C for 30 min) one hour before, during, or one hour after local irradiation to determine the effect of hyperthermia on <span class="hlt">radiation</span> damage. An ultrasound beam was used to <span class="hlt">induce</span> hyperthermia. The urinary concentrations of total protein and albumin were used as criteria of kidney injury. Hyperthermia alone did not <span class="hlt">induce</span> proteinuria. <span class="hlt">Radiation</span> alone produced proteinuria that was not correlated with dose. Hyperthermia <span class="hlt">induced</span> during or after irradiation resulted in a thermal enhancement factor of 1.29+/-.33. Hyperthermia <span class="hlt">induced</span> one hour before irradiation resulted in a thermal enhancement factor of 0.88+/-.05, indicating a radioprotective effect. To the authors' knowledge, this is the first time such an effect has been shown.</p> <div class="credits"> <p class="dwt_author">Baker, D.G.; Sager, H.T.; Elkon, D.; Constable, W.; Rinehart, L.; Wills, M.; Savory, J.; Lacher, D.</p> <p class="dwt_publisher"></p> <p class="publishDate">1982-11-01</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://www.osti.gov/scitech/biblio/6527268"> <span id="translatedtitle">The response of kidney to ionizing <span class="hlt">radiation</span> combined with hyperthermia <span class="hlt">induced</span> by ultrasound</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">Mouse kidneys were made hyperthermic (42.5 degrees C for 30 min) one hour before, during, or one hour after local irradiation to determine the effect of hyperthermia on <span class="hlt">radiation</span> damage. An ultrasound beam was used to <span class="hlt">induce</span> hyperthermia. The urinary concentrations of total protein and albumin were used as criteria of kidney injury. Hyperthermia alone did not <span class="hlt">induce</span> proteinuria. <span class="hlt">Radiation</span> alone produced proteinuria that was not correlated with dose. Hyperthermia <span class="hlt">induced</span> during or after irradiation resulted in a thermal enhancement factor of 1.29 +/- .33. Hyperthermia <span class="hlt">induced</span> one hour before irradiation resulted in a thermal enhancement factor of 0.88 +/- .05, indicating a radioprotective effect. To the authors' knowledge, this is the first time such an effect has been shown.</p> <div class="credits"> <p class="dwt_author">Baker, D.G.; Sager, H.T.; Elkon, D.; Constable, W.; Rinehart, L.; Wills, M.; Savory, J.; Lacher, D.</p> <p class="dwt_publisher"></p> <p class="publishDate">1982-11-01</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.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3941603"> <span id="translatedtitle">New era of radiotherapy: an update in <span class="hlt">radiation-induced</span> lung disease</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">Over the last few decades, advances in radiotherapy (RT) technology have improved delivery of <span class="hlt">radiation</span> therapy dramatically. Advances in treatment planning with the development of image-guided radiotherapy and in techniques such as proton therapy, allows the <span class="hlt">radiation</span> therapist to direct high doses of <span class="hlt">radiation</span> to the tumour. These advancements result in improved local regional control while reducing potentially damaging dosage to surrounding normal tissues. It is important for radiologists to be aware of the radiological findings from these advances in order to differentiate expected <span class="hlt">radiation-induced</span> lung injury (RILD) from recurrence, infection, and other lung diseases. In order to understand these changes and correlate them with imaging, the radiologist should have access to the <span class="hlt">radiation</span> therapy treatment plans. PMID:23473474</p> <div class="credits"> <p class="dwt_author">Benveniste, M. F. K.; Welsh, J.; Godoy, M. C. B.; Betancourt, S. L.; Mawlawi, O. R; Munden, R. F.</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">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=4128341"> <span id="translatedtitle">Unlocking the Combination: Potentiation of <span class="hlt">Radiation-Induced</span> Antitumor Responses with Immunotherapy</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">There is increasing evidence of the potential for <span class="hlt">radiation</span> therapy to generate antitumor immune responses. The mechanisms of this immune-activating potential include actions on tumor cells such as immunogenic cell death and phenotypic change. <span class="hlt">Radiation</span> modulates tumor cell surface expression of cell death receptors, tumor-associated antigens and adhesion molecules. This process of immunomodulation sensitizes tumor cells to immune-mediated killing. <span class="hlt">Radiation</span> also affects immune compartments, including antigen-presenting cells, cytotoxic T lymphocytes and humoral immunity, leading to specific antitumor immune responses. Recognizing the importance of immunity as a potentiator of response to <span class="hlt">radiation</span> leads to rational augmentation of antitumor immunity by combining <span class="hlt">radiation</span> and immunotherapy. Targeted immunotherapy manipulates the immune system in a way that best synergizes with <span class="hlt">radiation</span>. This article discusses the ability of <span class="hlt">radiation</span> monotherapy to <span class="hlt">induce</span> antitumor immunity, with a focus on the effect of <span class="hlt">radiation</span> on antigen-presenting cells and cytotoxic T lymphocytes. We define two important responses generated by tumor cells, immunogenic cell death and immunomodulation, both of which are <span class="hlt">radiation</span> dose-dependent. In conclusion, we describe the translation of several combination therapies from the preclinical to the clinical setting and identify opportunities for further exploration. PMID:24960415</p> <div class="credits"> <p class="dwt_author">Wattenberg, Max M.; Fahim, Ahmed; Ahmed, Mansoor M.; Hodge, James W.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</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.osti.gov/scitech/biblio/22224496"> <span id="translatedtitle">Sorafenib Enhances <span class="hlt">Radiation-Induced</span> Apoptosis in Hepatocellular Carcinoma by Inhibiting STAT3</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: Hepatocellular carcinoma (HCC) is one of the most common and lethal human malignancies. Lack of efficient therapy for advanced HCC is a pressing problem worldwide. This study aimed to determine the efficacy and mechanism of combined sorafenib and <span class="hlt">radiation</span> therapy treatment for HCC. Methods and Materials: HCC cell lines (PLC5, Huh-7, Sk-Hep1, and Hep3B) were treated with sorafenib, <span class="hlt">radiation</span>, or both, and apoptosis and signal transduction were analyzed. Results: All 4 HCC cell lines showed resistance to <span class="hlt">radiation-induced</span> apoptosis; however, this resistance could be reversed in the presence of sorafenib. Inhibition of phospho-STAT3 was found in cells treated with sorafenib or sorafenib plus <span class="hlt">radiation</span> and subsequently reduced the expression levels of STAT3-related proteins, Mcl-1, cyclin D1, and survivin. Silencing STAT3 by RNA interference overcame apoptotic resistance to <span class="hlt">radiation</span> in HCC cells, and the ectopic expression of STAT3 in HCC cells abolished the radiosensitizing effect of sorafenib. Moreover, sorafenib plus <span class="hlt">radiation</span> significantly suppressed PLC5 xenograft tumor growth. Conclusions: These results indicate that sorafenib sensitizes resistant HCC cells to <span class="hlt">radiation-induced</span> apoptosis via downregulating phosphorylation of STAT3 in vitro and in vivo.</p> <div class="credits"> <p class="dwt_author">Huang, Chao-Yuan [Department of Oncology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan (China) [Department of Oncology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan (China); Department of Radiological Technology, Yuanpei University, Hsinchu, Taiwan (China); Lin, Chen-Si [School of Veterinary Medicine, National Taiwan University Hospital, Taipei, Taiwan (China)] [School of Veterinary Medicine, National Taiwan University Hospital, Taipei, Taiwan (China); Tai, Wei-Tien; Hsieh, Chi-Ying [Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan (China) [Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan (China); National Center of Excellence for Clinical Trial and Research, National Taiwan University Hospital, Taipei, Taiwan (China); Shiau, Chung-Wai [Institute of Biopharmaceutical Sciences, National Yang-Ming University, Taipei, Taiwan (China)] [Institute of Biopharmaceutical Sciences, National Yang-Ming University, Taipei, Taiwan (China); Cheng, Ann-Lii [Department of Oncology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan (China) [Department of Oncology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan (China); National Center of Excellence for Clinical Trial and Research, National Taiwan University Hospital, Taipei, Taiwan (China); Chen, Kuen-Feng, E-mail: kfchen1970@ntu.edu.tw [Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan (China) [Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan (China); National Center of Excellence for Clinical Trial and Research, National Taiwan University Hospital, Taipei, Taiwan (China)</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-07-01</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.ncbi.nlm.nih.gov/pubmed/25501166"> <span id="translatedtitle">Physiological and morphological responses <span class="hlt">induced</span> by ?-particle <span class="hlt">radiation</span> on Arabidopsis thaliana embryos.</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 (a)-particle <span class="hlt">radiation</span> has been thoroughly studied in the occupational and residential environments, but biological mechanisms <span class="hlt">induced</span> by a-particle <span class="hlt">radiation</span> on plants are not clearly understood. In this study, <span class="hlt">radiation</span> effects were examined using different total doses (1, 10, 100 Gy, respectively) of 241Am, a-particle on Arabidopsis embryos. No significant difference in the germination percentage was observed between the 3 levels of doses and the control. Germination speed and root length were increased by treatment with the 1-Gy dose of a-particles, and decreased by treatment with 10- and 100-Gy doses. Moreover, the bending degree of roots increased with <span class="hlt">radiation</span> dose, and the roots showed an "S" shape when treated with the 100-Gy dose. Root bending under the 100-Gy dose was inhibited by scavengers of reactive oxygen species (ROS). Root gravitropism and root length may respond to the consistency of ROS <span class="hlt">induced</span> by irradiation. Further analysis of the physiological effects revealed that an increase in a-particle <span class="hlt">radiation</span> intensity enhanced the activity of catalase and the content of malondialdehyde, but superoxide dismutase activity was reduced by treatment with 100-Gy <span class="hlt">radiation</span> of a-particles, suggesting that the high linear energy transfer of a-particles may cause a relatively high level of membrane lipid preoxidation and high accumulation of ROS. ROS showed both physiological and morphological responses following exposure to ?-particle <span class="hlt">radiation</span> in Arabidopsis embryos. PMID:25501166</p> <div class="credits"> <p class="dwt_author">Ren, J; Liu, L; Jin, X L; Fu, S L; Ding, Z C</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</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.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2949714"> <span id="translatedtitle">Emerging role of <span class="hlt">radiation</span> <span class="hlt">induced</span> bystander effects: Cell communications and 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">Ionizing <span class="hlt">radiation</span> is an invaluable diagnostic and treatment tool used in various clinical applications. On the other hand, <span class="hlt">radiation</span> is a known cytotoxic with a potential DNA damaging and carcinogenic effects. However, the biological effects of low and high linear energy transfer (LET) <span class="hlt">radiations</span> are considerably more complex than previously thought. In the past decade, evidence has mounted for a novel biological phenomenon termed as "bystander effect" (BE), wherein directly irradiated cells transmit damaging signals to non-irradiated cells thereby <span class="hlt">inducing</span> a response similar to that of irradiated cells. BE can also be <span class="hlt">induced</span> in various cells irrespective of the type of <span class="hlt">radiation</span>, and the BE may be more damaging in the longer term than direct <span class="hlt">radiation</span> exposure. BE is mediated either through gap-junctions or via soluble factors released by irradiated cells. DNA damage response mechanisms represent a vital line of defense against exogenous and endogenous damage caused by <span class="hlt">radiation</span> and promote two distinct outcomes: survival and the maintenance of genomic stability. The latter is critical for cancer avoidance. Therefore, efforts to understand and modulate the bystander responses will provide new approaches to cancer therapy and prevention. This review overviews the emerging role of BE of low and high LET <span class="hlt">radiations</span> on the genomic instability of bystander cells and its possible implications for carcinogenesis. PMID:20831828</p> <div class="credits"> <p class="dwt_author"></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">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.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3005325"> <span id="translatedtitle">Genetic analysis of <span class="hlt">radiation-induced</span> changes in human gene expression</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">Humans are exposed to <span class="hlt">radiation</span> through the environment and in medical settings. To deal with <span class="hlt">radiation-induced</span> damage, cells mount complex responses that rely on changes in gene expression. These gene expression responses differ greatly between individuals1 and contribute to individual differences in response to <span class="hlt">radiation</span>2. Here we identify regulators that influence expression levels of <span class="hlt">radiation</span>-responsive genes. We treated <span class="hlt">radiation-induced</span> changes in gene expression as quantitative phenotypes3,4, and conducted genetic linkage and association studies to map their regulators. For more than 1,200 of these phenotypes there was significant evidence of linkage to specific chromosomal regions. Nearly all of the regulators act in trans to influence the expression of their target genes; there are very few cis-acting regulators. Some of the transacting regulators are transcription factors, but others are genes that were not known to have a regulatory function in <span class="hlt">radiation</span> response. These results have implications for our basic and clinical understanding of how human cells respond to <span class="hlt">radiation</span>. PMID:19349959</p> <div class="credits"> <p class="dwt_author">Smirnov, Denis A.; Morley, Michael; Shin, Eunice; Spielman, Richard S.; Cheung, Vivian G.</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">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.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3883787"> <span id="translatedtitle"><span class="hlt">Radiation-