Terrestrial Vegetation Dynamics, Global Climate Controls, and Extreme Events

NASA Astrophysics Data System (ADS)

Klooster, S.; Potter, C.; Boriah, S.; Steinbach, M.; Kumar, V.

2006-12-01

Monthly greenness data from the Moderate Resolution Imaging Spectroradiometer (MODIS) was used to reconstruct vegetation dynamics in response to climate patterns over the period 2000-2005. Results suggest that plant growth over extensive land areas of southern Africa and Central Asia were the most closely coupled of any major land area to El Niño-Southern Oscillation (ENSO) effects on regional climate. Others land areas strongly tied to recent ENSO climate effects were in northern Canada, Alaska, western United States, northern Mexico, northern Argentina, and Australia. Localized variations in precipitation were the most common controllers of monthly values for the fraction absorbed of photosynthetically active radiation (FPAR) over these regions. In addition to the areas cited above, seasonal FPAR values were closely coupled to rainfall patterns in grassland and cropland areas of the northern and central United States. Historical associations between global vegetation FPAR and atmospheric carbon dioxide anomalies suggest that the terrestrial biosphere can contribute major fluxes of carbon dioxide during major drought events, such as those triggered by the 1997-98 El Niño event.

Terrestrial vegetation dynamics and global climate controls

NASA Astrophysics Data System (ADS)

Potter, Christopher; Boriah, Shyam; Steinbach, Michael; Kumar, Vipin; Klooster, Steven

2008-07-01

Monthly data from the moderate resolution imaging spectroradiometer (MODIS) and its predecessor satellite sensors was used to reconstruct vegetation dynamics in response to climate patterns over the period 1983 2005. Results suggest that plant growth over extensive land areas of southern Africa and Central Asia were the most closely coupled of any major land area to El Niño southern oscillation (ENSO) effects on regional climate. Others land areas strongly tied to recent ENSO climate effects were in northern Canada, Alaska, western US, northern Mexico, northern Argentina, and Australia. Localized variations in precipitation were the most common controllers of monthly values for the fraction absorbed of photosynthetically active radiation (FPAR) over these regions. In addition to the areas cited above, seasonal FPAR values from MODIS were closely coupled to rainfall patterns in grassland and cropland areas of the northern and central US. Historical associations between global vegetation FPAR and atmospheric carbon dioxide (CO2) anomalies suggest that the terrestrial biosphere can contribute major fluxes of CO2 during major drought events, such as those triggered by 1997 1998 El Niño event.

The SMAP Level-4 ECO Project: Linking the Terrestrial Water and Carbon Cycles

NASA Technical Reports Server (NTRS)

Kolassa, J.; Reichle, R. H.; Liu, Qing; Koster, Randal D.

2017-01-01

The SMAP (Soil Moisture Active Passive) Level-4 projects aims to develop a fully coupled hydrology-vegetation data assimilation algorithm to generate improved estimates of modeled hydrological fields and carbon fluxes. This includes using the new NASA Catchment-CN (Catchment-Carbon-Nitrogen) model, which combines the Catchment land surface hydrology model with dynamic vegetation components from the Community Land Model version 4 (CLM4). As such, Catchment-CN allows a more realistic, fully coupled feedback between the land hydrology and the biosphere. The L4 ECO project further aims to inform the model through the assimilation of Soil Moisture Active Passive (SMAP) brightness temperature observations as well as observations of Moderate Resolution Imaging Spectroradiometer (MODIS) fraction of absorbed photosynthetically active radiation (FPAR). Preliminary results show that the assimilation of SMAP observations leads to consistent improvements in the model soil moisture skill. An evaluation of the Catchment-CN modeled vegetation characteristics showed that a calibration of the model's vegetation parameters is required before an assimilation of MODIS FPAR observations is feasible.

Biophysical characterization and management effects on semiarid rangeland observed from Landsat ETM+ data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fang, Hongliang; Liang, Shunlin; McClaran, Mitchell P.

2005-01-20

Semi-arid rangelands are very sensitive to global climatic change; studies of their biophysical attributes are crucial to understanding the dynamics of rangeland ecosystems under human disturbance. In the Santa Rita Experimental Range (SRER), Arizona, the vegetation has changed considerably and there have been many management activities applied. This study calculates seven surface variables: the enhanced vegetation index (EVI), the normalized difference vegetation index (NDVI), surface albedos (total shortwave, visible and near-infrared), leaf area index (LAI) and the fraction of photosynthetically active radiation absorbed by green vegetation (FPAR) from the Enhanced Thematic Mapper (ETM+) data. Comparison with the MODIS (Moderate Resolutionmore » Imaging Spectroradiometer) vegetation index and albedo products indicate they agree well with our estimates from ETM+ while their LAI and FPAR are larger than ETM+. Human disturbance has significantly changed the cover types and biophysical conditions. Statistical tests indicate that surface albedos increased and FPAR decreased at all sites. The recovery will require more than 67 years, and is about 50% complete within 40 years at the higher elevation. Grass cover, vegetation indices, albedos and LAI recovered from cutting faster at the higher elevation. Woody plants, vegetation indices and LAI have recovered to their original characteristics after 65 years at the lower elevation. More studies are needed to examine the spectral characteristics of different ground components.« less

Predicting Phenologic Response to Water Stress and Implications for Carbon Uptake across the Southeast U.S.

NASA Astrophysics Data System (ADS)

Lowman, L.; Barros, A. P.

2016-12-01

Representation of plant photosynthesis in modeling studies requires phenologic indicators to scale carbon assimilation by plants. These indicators are typically the fraction of photosynthetically active radiation (FPAR) and leaf area index (LAI) which represent plant responses to light and water availability, as well as temperature constraints. In this study, a prognostic phenology model based on the growing season index is adapted to determine the phenologic indicators of LAI and FPAR at the sub-daily scale based on meteorological and soil conditions. Specifically, we directly model vegetation green-up and die-off responses to temperature, vapor pressure deficit, soil water potential, and incoming solar radiation. The indices are based on the properties of individual plant functional types, driven by observational data and prior modeling applications. First, we describe and test the sensitivity of the carbon uptake response to predicted phenology for different vegetation types. Second, the prognostic phenology model is incorporated into a land-surface hydrology model, the Duke Coupled Hydrology Model with Prognostic Vegetation (DCHM-PV), to demonstrate the impact of dynamic phenology on modeled carbon assimilation rates and hydrologic feedbacks. Preliminary results show reduced carbon uptake rates when incorporating a prognostic phenology model that match well against the eddy-covariance flux tower observations. Additionally, grassland vegetation shows the most variability in LAI and FPAR tied to meteorological and soil conditions. These results highlight the need to incorporate vegetation-specific responses to water limitation in order to accurately estimate the terrestrial carbon storage component of the global carbon budget.

BOREAS Level-0 ER-2 Daedalus TMS Imagery Digital Counts in BIL Format

NASA Technical Reports Server (NTRS)

Newcomer, Jeffrey A.; Dominguez, Roseanne; Hall, Forrest G. (Editor)

2000-01-01

The level-0 Daedalus Thematic Mapper Simulator (TMS) imagery, along with the other remotely sensed images, was collected to provide spatially extensive information about radiant energy over the primary BOReal Ecosystem-Atmosphere Study (BOREAS) study areas. This information includes detailed land cover and biophysical parameter maps such as fraction of Photosynthetically Active Radiation (fPAR) and Leaf Area Index (LAI). Two flights of the Daedalus TMS instrument were made onboard the ER-2 aircraft on 16-Sep-1994 and 17-Sep-1994.

Sources of Uncertainty in the Prediction of LAI / fPAR from MODIS

NASA Technical Reports Server (NTRS)

Dungan, Jennifer L.; Ganapol, Barry D.; Brass, James A. (Technical Monitor)

2002-01-01

To explicate the sources of uncertainty in the prediction of biophysical variables over space, consider the general equation: where z is a variable with values on some nominal, ordinal, interval or ratio scale; y is a vector of input variables; u is the spatial support of y and z ; x and u are the spatial locations of y and z , respectively; f is a model and B is the vector of the parameters of this model. Any y or z has a value and a spatial extent which is called its support. Viewed in this way, categories of uncertainty are from variable (e.g. measurement), parameter, positional. support and model (e.g. structural) sources. The prediction of Leaf Area Index (LAI) and the fraction of absorbed photosynthetically active radiation (fPAR) are examples of z variables predicted using model(s) as a function of y variables and spatially constant parameters. The MOD15 algorithm is an example of f, called f(sub 1), with parameters including those defined by one of six biome types and solar and view angles. The Leaf Canopy Model (LCM)2, a nested model that combines leaf radiative transfer with a full canopy reflectance model through the phase function, is a simpler though similar radiative transfer approach to f(sub 1). In a previous study, MOD15 and LCM2 gave similar results for the broadleaf forest biome. Differences between these two models can be used to consider the structural uncertainty in prediction results. In an effort to quantify each of the five sources of uncertainty and rank their relative importance for the LAI/fPAR prediction problem, we used recent data for an EOS Core Validation Site in the broadleaf biome with coincident surface reflectance, vegetation index, fPAR and LAI products from the Moderate Resolution Imaging Spectrometer (MODIS). Uncertainty due to support on the input reflectance variable was characterized using Landsat ETM+ data. Input uncertainties were propagated through the LCM2 model and compared with published uncertainties from the MOD15 algorithm.

Greener Pastures in Northern Queensland, Australia

NASA Technical Reports Server (NTRS)

2004-01-01

After a 19 month rainfall deficiency, heavy rainfall during January 2004 brought drought relief to much of northern Queensland. Local graziers hope for good long-term responses in pasture growth from the heavy rains. These images and maps from the Multi-angle Imaging SpectroRadiometer (MISR) portray part of Australia's Mitchell Grasslands bioregion before summer rainfall, on October 18, 2003 (left) and afterwards, on February 7, 2004 (right).

The top pair of images are natural color views from MISR's nadir camera. The green areas in the post-rainfall image highlight the growth of vegetation. The middle panels show the reflectivity of the surface over the photosynthetically active region (PAR) of visible light (400 - 700 nm), expressed as a directional-hemispherical reflectance (DHR-PAR), or albedo. That portion of the radiation that is not reflected back to the atmosphere or space is absorbed by either the vegetation or the soil. The fraction of PAR radiation absorbed by green vegetation, known as FPAR, is shown in the bottom panels. FPAR is one of the quantities that establishes the photosynthetic and carbon uptake efficiency of live vegetation. MISR's FPAR product makes use of aerosol retrievals to correct for atmospheric scattering and absorption effects, and uses plant canopy structural models to determine the partitioning of solar radiation. Both of these aspects are facilitated by the multiangular nature of the MISR measurements.

The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously and every 9 days views the entire globe between 82 degrees north and 82 degrees south latitude. These data products were generated from a portion of the imagery acquired during Terra orbits 20397 and 22028. The panels cover an area of about 290 kilometers x 228 kilometers, and utilize data from blocks 106 to 108 within World Reference System-2 path 96.

MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

Generating Vegetation Leaf Area Index Earth System Data Record from Multiple Sensors. Part 1; Theory

NASA Technical Reports Server (NTRS)

Ganguly, Sangram; Schull, Mitchell A.; Samanta, Arindam; Shabanov, Nikolay V.; Milesi, Cristina; Nemani, Ramakrishna R.; Knyazikhin, Yuri; Myneni, Ranga B.

2008-01-01

The generation of multi-decade long Earth System Data Records (ESDRs) of Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation absorbed by vegetation (FPAR) from remote sensing measurements of multiple sensors is key to monitoring long-term changes in vegetation due to natural and anthropogenic influences. Challenges in developing such ESDRs include problems in remote sensing science (modeling of variability in global vegetation, scaling, atmospheric correction) and sensor hardware (differences in spatial resolution, spectral bands, calibration, and information content). In this paper, we develop a physically based approach for deriving LAI and FPAR products from the Advanced Very High Resolution Radiometer (AVHRR) data that are of comparable quality to the Moderate resolution Imaging Spectroradiometer (MODIS) LAI and FPAR products, thus realizing the objective of producing a long (multi-decadal) time series of these products. The approach is based on the radiative transfer theory of canopy spectral invariants which facilitates parameterization of the canopy spectral bidirectional reflectance factor (BRF). The methodology permits decoupling of the structural and radiometric components and obeys the energy conservation law. The approach is applicable to any optical sensor, however, it requires selection of sensor-specific values of configurable parameters, namely, the single scattering albedo and data uncertainty. According to the theory of spectral invariants, the single scattering albedo is a function of the spatial scale, and thus, accounts for the variation in BRF with sensor spatial resolution. Likewise, the single scattering albedo accounts for the variation in spectral BRF with sensor bandwidths. The second adjustable parameter is data uncertainty, which accounts for varying information content of the remote sensing measurements, i.e., Normalized Difference Vegetation Index (NDVI, low information content), vs. spectral BRF (higher information content). Implementation of this approach indicates good consistency in LAI values retrieved from NDVI (AVHRRmode) and spectral BRF (MODIS-mode). Specific details of the implementation and evaluation of the derived products are detailed in the second part of this two-paper series.

Vegetation Earth System Data Record from DSCOVR EPIC Observations

NASA Astrophysics Data System (ADS)

Knyazikhin, Y.; Song, W.; Yang, B.; Mottus, M.; Rautiainen, M.; Stenberg, P.

2017-12-01

The NASA's Earth Polychromatic Imaging Camera (EPIC) onboard NOAA's Deep Space Climate Observatory (DSCOVR) mission was launched on February 11, 2015 to the Sun-Earth Lagrangian L1 point where it began to collect radiance data of the entire sunlit Earth every 65 to 110 min in June 2015. It provides imageries in near backscattering directions with the scattering angle between 168° and 176° at ten ultraviolet to near infrared (NIR) narrow spectral bands centered at 317.5 (band width 1.0) nm, 325.0 (2.0) nm, 340.0 (3.0) nm, 388.0 (3.0) nm, 433.0 (3.0) nm, 551.0 (3.0) nm, 680.0 (3.0) nm, 687.8 (0.8) nm, 764.0 (1.0) nm and 779.5 (2.0) nm. This poster presents current status of the Vegetation Earth System Data Record of global Leaf Area Index (LAI), solar zenith angle dependent Sunlit Leaf Area Index (SLAI), Fraction vegetation absorbed Photosynthetically Active Radiation (FPAR) and Normalized Difference Vegetation Index (NDVI) derived from the DSCOVR EPIC observations. Whereas LAI is a standard product of many satellite missions, the SLAI is a new satellite-derived parameter. Sunlit and shaded leaves exhibit different radiative response to incident Photosynthetically Active Radiation (400-700 nm), which in turn triggers various physiological and physical processes required for the functioning of plants. FPAR, LAI and SLAI are key state parameters in most ecosystem productivity models and carbon/nitrogen cycle. The product at 10 km sinusoidal grid and 65 to 110 min temporal frequency as well as accompanying Quality Assessment (QA) variables will be publicly available from the NASA Langley Atmospheric Science Data Center. The Algorithm Theoretical Basis (ATBD) and product validation strategy are also discussed in this poster.

Multi-Decadal Pathfinder Data Sets of Global Land Biophysical Variables from AVHRR and MODIS and their Use in GCM Studies of Biogeophysics and Biogeochemistry

NASA Technical Reports Server (NTRS)

Myneni, Ranga

2003-01-01

The problem of how the scale, or spatial resolution, of reflectance data impacts retrievals of vegetation leaf area index (LAI) and fraction absorbed photosynthetically active radiation (PAR) has been investigated. We define the goal of scaling as the process by which it is established that LAI and FPAR values derived from coarse resolution sensor data equal the arithmetic average of values derived independently from fine resolution sensor data. The increasing probability of land cover mixtures with decreasing resolution is defined as heterogeneity, which is a key concept in scaling studies. The effect of pixel heterogeneity on spectral reflectances and LAI/FPAR retrievals is investigated with 1 km Advanced Very High Resolution Radiometer (AVHRR) data aggregated to different coarse spatial resolutions. It is shown that LAI retrieval errors at coarse resolution are inversely related to the proportion of the dominant land cover in such pixel. Further, large errors in LAI retrievals are incurred when forests are minority biomes in non-forest pixels compared to when forest biomes are mixed with one another, and vice-versa. A physically based technique for scaling with explicit spatial resolution dependent radiative transfer formulation is developed. The successful application of this theory to scaling LAI retrievals from AVHRR data of different resolutions is demonstrated

Assessment of Vegetation Responses and Sensitivity to the Millennium Drought in Australia

NASA Astrophysics Data System (ADS)

Jiao, T.; Williams, C. A.

2016-12-01

During the period from 1997 to 2009, Australia experienced one of the most severe and persistent drought known as the Millennium Drought (MD). Major water shortages were reported across the Australian continent as well as a great many tree mortality during and post this drought event. Given the projection of hotter and drier conditions for much of the continent, it is critical to analyze the impacts of climate extremes like MD as an indicator of possible impacts of future trends. Despite many field investigation, large-area monitoring of vegetation decline from MD remains lacking. Here, multi-source remote sensing datasets and novel methods were employed to assess the impacts of MD on vegetation in Australia in terms of the magnitude and sensitivity. Vegetation variables examined include fraction of photosynthetically absorbed radiation (fPar), vegetation optical depth (VOD) and aboveground biomass (AGB). Drought indicators are calculated based on precipitation and potential evapotranspiration from meteorological data. We found consistent spatial patterns in drought-induced declines among fPar, VOD and AGB. Common declines were observed in the east of New South Wales (NSW), the southeast of Queensland, the center and east of Victoria, and Tasmania. Severe declines (>0.2) in fPar concentrate in open forests and shrub lands while regions with more than 0.1 of decline in VOD are found widely across biome types. The net decrease in AGB could reach more than 20 Mg C per ha in the west of Victoria and the southwest of NSW. Sensitivity analysis shows that forests followed by herbaceous are more sensitive to drought than shrubs in terms of declines in fPar and VOD. In addition, vegetation tends to have larger sensitivity in semi-arid or semi-mesic regions than in areas that are either too dry or too wet.

Catchment Water-Energy Balance Model: Development and Applications

NASA Astrophysics Data System (ADS)

Yang, D.; Yang, H.

2017-12-01

International Hydrological community has widely recognized that the catchment water-energy balance exists, which can be expressed as a general form of E/P = f(E0/P, c), where P is precipitation, E0 is potential evaporation, and c is a parameter. Many empirical/rational formulations of the catchment water-energy balance have been proposed. Several analytical solutions of the water-energy balance equation E/P = f(E0/P, c) have been derived by using dimensional analysis and mathematic reasoning and introducing additional boundary conditions. This paper will summarize the catchment water-energy balance equations and discuss their advantages and limitations. Catchment hydrology has been greatly influenced by the intensive variability in land use/cover, precipitation and air temperature due to climate change and local human activities. The water-energy balance equation, which are usually called the Budyko framework is widely used to analyze the impacts of climate and landscape changes on regional hydrology especially the annual runoff change. In order to quantify impacts of climate change and landscape change on the catchment runoff, the climate elasticity and landscape elasticity are estimated theoretically from the catchment water-energy balance equation. The elasticity of runoff has less of a dependency on the aridity index when the climate is drier (larger aridity index). The precipitation elasticity of runoff was close to 1.0 and that of potential evaporation close to 0.0 in the extreme humid climate with no relation to the landscape conditions, which implies that catchment water balance under extremely wet condition is controlled mainly by the climate condition. We establishes a relationship between the change in the landscape parameter in the catchment water-energy balance equation and vegetation change represented by fPAR, the fraction of Photosynthetically Active Radiation absorbed by vegetation. The fPAR elasticity of runoff is introduced and estimated over China, which indicate that runoff is more sensitive to the change in fPAR in relatively dry catchments. This paper will summarize applications of the water-energy balance equation and discuss on the future development.

Sea Surface Temperature Influence on Terrestrial Gross Primary Production along the Southern California Current.

PubMed

Reimer, Janet J; Vargas, Rodrigo; Rivas, David; Gaxiola-Castro, Gilberto; Hernandez-Ayon, J Martin; Lara-Lara, Ruben

2015-01-01

Some land and ocean processes are related through connections (and synoptic-scale teleconnections) to the atmosphere. Synoptic-scale atmospheric (El Niño/Southern Oscillation [ENSO], Pacific Decadal Oscillation [PDO], and North Atlantic Oscillation [NAO]) decadal cycles are known to influence the global terrestrial carbon cycle. Potentially, smaller scale land-ocean connections influenced by coastal upwelling (changes in sea surface temperature) may be important for local-to-regional water-limited ecosystems where plants may benefit from air moisture transported from the ocean to terrestrial ecosystems. Here we use satellite-derived observations to test potential connections between changes in sea surface temperature (SST) in regions with strong coastal upwelling and terrestrial gross primary production (GPP) across the Baja California Peninsula. This region is characterized by an arid/semiarid climate along the southern California Current. We found that SST was correlated with the fraction of photosynthetic active radiation (fPAR; as a proxy for GPP) with lags ranging from 0 to 5 months. In contrast ENSO was not as strongly related with fPAR as SST in these coastal ecosystems. Our results show the importance of local-scale changes in SST during upwelling events, to explain the variability in GPP in coastal, water-limited ecosystems. The response of GPP to SST was spatially-dependent: colder SST in the northern areas increased GPP (likely by influencing fog formation), while warmer SST at the southern areas was associated to higher GPP (as SST is in phase with precipitation patterns). Interannual trends in fPAR are also spatially variable along the Baja California Peninsula with increasing secular trends in subtropical regions, decreasing trends in the most arid region, and no trend in the semi-arid regions. These findings suggest that studies and ecosystem process based models should consider the lateral influence of local-scale ocean processes that could influence coastal ecosystem productivity.

Sea Surface Temperature Influence on Terrestrial Gross Primary Production along the Southern California Current

PubMed Central

Reimer, Janet J.; Vargas, Rodrigo; Rivas, David; Gaxiola-Castro, Gilberto; Hernandez-Ayon, J. Martin; Lara-Lara, Ruben

2015-01-01

Some land and ocean processes are related through connections (and synoptic-scale teleconnections) to the atmosphere. Synoptic-scale atmospheric (El Niño/Southern Oscillation [ENSO], Pacific Decadal Oscillation [PDO], and North Atlantic Oscillation [NAO]) decadal cycles are known to influence the global terrestrial carbon cycle. Potentially, smaller scale land-ocean connections influenced by coastal upwelling (changes in sea surface temperature) may be important for local-to-regional water-limited ecosystems where plants may benefit from air moisture transported from the ocean to terrestrial ecosystems. Here we use satellite-derived observations to test potential connections between changes in sea surface temperature (SST) in regions with strong coastal upwelling and terrestrial gross primary production (GPP) across the Baja California Peninsula. This region is characterized by an arid/semiarid climate along the southern California Current. We found that SST was correlated with the fraction of photosynthetic active radiation (fPAR; as a proxy for GPP) with lags ranging from 0 to 5 months. In contrast ENSO was not as strongly related with fPAR as SST in these coastal ecosystems. Our results show the importance of local-scale changes in SST during upwelling events, to explain the variability in GPP in coastal, water-limited ecosystems. The response of GPP to SST was spatially-dependent: colder SST in the northern areas increased GPP (likely by influencing fog formation), while warmer SST at the southern areas was associated to higher GPP (as SST is in phase with precipitation patterns). Interannual trends in fPAR are also spatially variable along the Baja California Peninsula with increasing secular trends in subtropical regions, decreasing trends in the most arid region, and no trend in the semi-arid regions. These findings suggest that studies and ecosystem process based models should consider the lateral influence of local-scale ocean processes that could influence coastal ecosystem productivity. PMID:25923109

Elucidating Inherent Uncertainties in Data Assimilation for Predictions Incorporating Non-stationary Processes - Focus on Predictive Phenology

NASA Astrophysics Data System (ADS)

Lowman, L.; Barros, A. P.

2017-12-01

Data assimilation (DA) is the widely accepted procedure for estimating parameters within predictive models because of the adaptability and uncertainty quantification offered by Bayesian methods. DA applications in phenology modeling offer critical insights into how extreme weather or changes in climate impact the vegetation life cycle. Changes in leaf onset and senescence, root phenology, and intermittent leaf shedding imply large changes in the surface radiative, water, and carbon budgets at multiple scales. Models of leaf phenology require concurrent atmospheric and soil conditions to determine how biophysical plant properties respond to changes in temperature, light and water demand. Presently, climatological records for fraction of photosynthetically active radiation (FPAR) and leaf area index (LAI), the modelled states indicative of plant phenology, are not available. Further, DA models are typically trained on short periods of record (e.g. less than 10 years). Using limited records with a DA framework imposes non-stationarity on estimated parameters and the resulting predicted model states. This talk discusses how uncertainty introduced by the inherent non-stationarity of the modeled processes propagates through a land-surface hydrology model coupled to a predictive phenology model. How water demand is accounted for in the upscaling of DA model inputs and analysis period serves as a key source of uncertainty in the FPAR and LAI predictions. Parameters estimated from different DA effectively calibrate a plant water-use strategy within the land-surface hydrology model. For example, when extreme droughts are included in the DA period, the plants are trained to uptake water, transpire, and assimilate carbon under favorable conditions and quickly shut down at the onset of water stress.

The 2010 Russian Drought Impact on Satellite Measurements of Solar-Induced Chlorophyll Fluorescence: Insights from Modeling and Comparisons with the Normalized Differential Vegetation Index (NDVI)

NASA Technical Reports Server (NTRS)

Yoshida, Y.; Joiner, J.; Tucker, C.; Berry, J.; Lee, J. -E.; Walker, G.; Reichle, R.; Koster, R.; Lyapustin, A.; Wang, Y.

2015-01-01

We examine satellite-based measurements of chlorophyll solar-induced fluorescence (SIF) over the region impacted by the Russian drought and heat wave of 2010. Like the popular Normalized Difference Vegetation Index (NDVI) that has been used for decades to measure photosynthetic capacity, SIF measurements are sensitive to the fraction of absorbed photosynthetically-active radiation (fPAR). However, in addition, SIF is sensitive to the fluorescence yield that is related to the photosynthetic yield. Both SIF and NDVI from satellite data show drought-related declines early in the growing season in 2010 as compared to other years between 2007 and 2013 for areas dominated by crops and grasslands. This suggests an early manifestation of the dry conditions on fPAR. We also simulated SIF using a global land surface model driven by observation-based meteorological fields. The model provides a reasonable simulation of the drought and heat impacts on SIF in terms of the timing and spatial extents of anomalies, but there are some differences between modeled and observed SIF. The model may potentially be improved through data assimilation or parameter estimation using satellite observations of SIF (as well as NDVI). The model simulations also offer the opportunity to examine separately the different components of the SIF signal and relationships with Gross Primary Productivity (GPP).

BOREAS Level-3s Landsat TM Imagery Scaled At-sensor Radiance in LGSOWG Format

NASA Technical Reports Server (NTRS)

Nickeson, Jaime; Knapp, David; Newcomer, Jeffrey A.; Cihlar, Josef; Hall, Forrest G. (Editor)

2000-01-01

For BOReal Ecosystem-Atmosphere Study (BOREAS),the level-3s Landsat Thematic Mapper (TM) data, along with the other remotely sensed images,were collected in order to provide spatially extensive information over the primary study areas. This information includes radiant energy,detailed land cover, and biophysical parameter maps such as Fraction of Photosynthetically Active Radiation (FPAR) and Leaf area Index (LAI). CCRS collected and supplied the level-3s images to BOREAS for use in the remote sensing research activities. Geographically,the bulk of the level-3s images cover the BOREAS Northern Study Area (NSA) and Southern Study Area (SSA) with a few images covering the area between the NSA and SSA. Temporally,the images cover the period of 22-Jun-1984 to 30-Jul-1996. The images are available in binary,image-format files.

Assessment of Vegetation Responses and Sensitivity to the Millennium Drought in Australia

NASA Astrophysics Data System (ADS)

Jiao, T.; Williams, C. A.

2017-12-01

During the period from 1997 to 2009, Australia experienced one of the most severe and persistent drought known as the Millennium Drought (MD). Major water shortages were reported across the Australian continent as well as a great many tree mortality during and post this drought event. Given the projection of hotter and drier conditions for much of the continent (Hughes 2003), it is critical to analyze the impacts of climate extremes like MD as an indicator of possible impacts of future trends. A few drought assessments have been performed for the MD but their utilization of single-source Remote sensing data like vegetation indices makes it difficult to produce a comprehensive understanding of drought responses for diverse ecosystems in Australia. Furthermore, methods adopted in past drought assessments did not distinguish vegetation responses to drought events with different intensity, duration and sequence, which are critically important in determining the magnitude of vegetation responses to drought. Here, multi-source remote sensing datasets and an event-based drought assessment method were employed to assess the impacts of MD on vegetation in Australia in terms of the magnitude and sensitivity. Vegetation variables examined include fraction of photosynthetically absorbed radiation (Fpar), vegetation optical depth (VOD) and aboveground biomass (AGB). Drought indicators were calculated based on precipitation and potential evapotranspiration. Results show that most of Eastern Australia experienced abnormal water deficit during the MD and drought intensity was greatest in humid regions. The decline in aboveground biomass (ABC) demonstrates consistent variation with drought intensity across aridity levels. Drought impacts on Fpar and VOD were greatest at intermediate dryness and for woodier ecosystems, with impacts appearing in Fpar before VOD. Drought sensitivity was also greatest at intermediate dryness and for woodier ecosystems. The small difference in drought sensitivity, in terms of Fpar and VOD, across biomes suggests that trees, shrubs, and herbaceous are equally vulnerable to canopy dieback while the high drought sensitivity of trees as shown in ABC implies that a large amount of carbon could be released to the atmosphere if intense and long-duration drought occurs in forested areas.

Assessment of the Broadleaf Crops Leaf Area Index Product from the Terra MODIS Instrument

NASA Technical Reports Server (NTRS)

Tan, Bin; Hu, Jiannan; Huang, Dong; Yang, Wenze; Zhang, Ping; Shabanov, Nikolay V.; Knyazikhin, Yuri; Nemani, Ramakrishna R.; Myneni, Ranga B.

2005-01-01

The first significant processing of Terra MODIS data, called Collection 3, covered the period from November 2000 to December 2002. The Collection 3 leaf area index (LAI) and fraction vegetation absorbed photosynthetically active radiation (FPAR) products for broadleaf crops exhibited three anomalies (a) high LAI values during the peak growing season, (b) differences in LAI seasonality between the radiative transfer-based main algorithm and the vegetation index based back-up algorithm, and (c) too few retrievals from the main algorithm during the summer period when the crops are at full flush. The cause of these anomalies is a mismatch between reflectances modeled by the algorithm and MODIS measurements. Therefore, the Look-Up-Tables accompanying the algorithm were revised and implemented in Collection 4 processing. The main algorithm with the revised Look-Up-Tables generated retrievals for over 80% of the pixels with valid data. Retrievals from the back-up algorithm, although few, should be used with caution as they are generated from surface reflectances with high uncertainties.

Using remote-sensing and the Simple Biosphere model (SiB4) to analyze the seasonality and productivity of the terrestrial biosphere.

NASA Astrophysics Data System (ADS)

Cheeseman, M.; Denning, S.; Baker, I. T.

2017-12-01

Understanding the variability and seasonality of carbon fluxes from the terrestrial biosphere is integral to understanding the mechanisms and drivers of the global carbon cycle. However, there are many regions across the globe where in situ observations are sparse, such as the Amazon rainforest and the African Sahel. The latest version of the Simple-Biosphere model (SiB4) predicts a suite of biophysical variables such as terrestrial carbon flux (GPP), solar induced fluorescence (SIF), fraction of photosynthetically active radiation (FPAR), and leaf area index (LAI). By comparing modeled values to a suite of satellite and in situ observations we produce a robust analysis of the seasonality and productivity of the terrestrial biosphere in a variety of biome types across the globe.

BOREAS Level-1B MAS Imagery At-sensor Radiance, Relative X and Y Coordinates

NASA Technical Reports Server (NTRS)

Strub, Richard; Strub, Richard; Newcomer, Jeffrey A.; Ungar, Stephen

2000-01-01

For BOReal Ecosystem-Atmosphere Study (BOREAS), the MODIS Airborne Simulator (MAS) images, along with the other remotely sensed data, were collected to provide spatially extensive information over the primary study areas. This information includes detailed land cover and biophysical parameter maps such as fraction of Photosynthetically Active Radiation (fPAR) and Leaf Area Index (LAI). Collection of the MAS images occurred over the study areas during the 1994 field campaigns. The level-1b MAS data cover the dates of 21-Jul-1994, 24-Jul-1994, 04-Aug-1994, and 08-Aug-1994. The data are not geographically/geometrically corrected; however, files of relative X and Y coordinates for each image pixel were derived by using the C-130 INS data in a MAS scan model. The data are provided in binary image format files.

April Showers Bring May Flowers to the Southern United States

NASA Technical Reports Server (NTRS)

2004-01-01

Vigorous vegetation growth in the Southern United States after heavy rains fell during April and early May, 2004, is quantified in these images and data products from the Multi-angle Imaging SpectroRadiometer (MISR). The images were acquired on April 1 (top set) and May 3 (bottom set), and extend through Kansas and Missouri, Oklahoma and Arkansas, and eastern Texas, with the Texas-Louisiana border at the bottom right-hand corner.

The left-hand images are natural-color views from MISR's nadir camera. In the month between the April and May images, the overall greenness is enhanced, and the Boston and Ouachita Mountains are transformed from brownish hues to vivid green. The city of Dallas, Texas, appears as the pale gray area at lower left and the Red River (which corresponds with the Texas-Oklahoma border) is apparent as the yellowish feature flowing toward the lower left-hand edge. Scattered clouds appear in the upper right-hand corners of both images. Quantitative values for the vegetation changes are provided by the center and right-hand images. The middle panels show Leaf Area Index (LAI), or the area of leaves per unit area of ground below them, as measured from above. The right-hand panels show FPAR, which is the fraction of the photosynthetically active region (PAR) of visible light (400 - 700 nm) absorbed by green vegetation. LAI and FPAR are two important quantities for monitoring the photosynthetic activity and carbon uptake efficiency of live vegetation. MISR's LAI and FPAR products make use of aerosol retrievals to correct for atmospheric scattering and absorption effects, and use plant canopy structural models to determine the partitioning of solar radiation. Both of these aspects are facilitated by the multiangular nature of the MISR measurements.

The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously and every 9 days views the entire globe between 82 degrees north and 82 degrees south latitude. These data products were generated from a portion of the imagery acquired during Terra orbits 22810 and 23276. The panels cover an area of about 380 kilometers x 704 kilometers, and utilize data from blocks 61 to 65 within World Reference System-2 path 26.

MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

Modeling spatially explicit fire impact on gross primary production in interior Alaska using satellite images coupled with eddy covariance

USGS Publications Warehouse

Huang, Shengli; Liu, Heping; Dahal, Devendra; Jin, Suming; Welp, Lisa R.; Liu, Jinxun; Liu, Shuguang

2013-01-01

In interior Alaska, wildfires change gross primary production (GPP) after the initial disturbance. The impact of fires on GPP is spatially heterogeneous, which is difficult to evaluate by limited point-based comparisons or is insufficient to assess by satellite vegetation index. The direct prefire and postfire comparison is widely used, but the recovery identification may become biased due to interannual climate variability. The objective of this study is to propose a method to quantify the spatially explicit GPP change caused by fires and succession. We collected three Landsat images acquired on 13 July 2004, 5 August 2004, and 6 September 2004 to examine the GPP recovery of burned area from 1987 to 2004. A prefire Landsat image acquired in 1986 was used to reconstruct satellite images assuming that the fires of 1987–2004 had not occurred. We used a light-use efficiency model to estimate the GPP. This model was driven by maximum light-use efficiency (Emax) and fraction of photosynthetically active radiation absorbed by vegetation (FPAR). We applied this model to two scenarios (i.e., an actual postfire scenario and an assuming-no-fire scenario), where the changes in Emax and FPAR were taken into account. The changes in Emax were represented by the change in land cover of evergreen needleleaf forest, deciduous broadleaf forest, and shrub/grass mixed, whose Emax was determined from three fire chronosequence flux towers as 1.1556, 1.3336, and 0.5098 gC/MJ PAR. The changes in FPAR were inferred from NDVI change between the actual postfire NDVI and the reconstructed NDVI. After GPP quantification for July, August, and September 2004, we calculated the difference between the two scenarios in absolute and percent GPP changes. Our results showed rapid recovery of GPP post-fire with a 24% recovery immediately after burning and 43% one year later. For the fire scars with an age range of 2–17 years, the recovery rate ranged from 54% to 95%. In addition to the averaging, our approach further revealed the spatial heterogeneity of fire impact on GPP, allowing one to examine the spatially explicit GPP change caused by fires.

BOREAS Level-3s SPOT Imagery: Scaled At-sensor Radiance in LGSOWG Format

NASA Technical Reports Server (NTRS)

Strub, Richard; Nickeson, Jaime; Newcomer, Jeffrey A.; Hall, Forrest G. (Editor); Cihlar, Josef

2000-01-01

For BOReal Ecosystem-Atmosphere Study (BOREAS), the level-3s Satellite Pour l'Observation de la Terre (SPOT) data, along with the other remotely sensed images, were collected in order to provide spatially extensive information over the primary study areas. This information includes radiant energy, detailed land cover, and biophysical parameter maps such as Fraction of Photosynthetically Active Radiation (FPAR) and Leaf Area Index (LAI). The SPOT images acquired for the BOREAS project were selected primarily to fill temporal gaps in the Landsat Thematic Mapper (TM) image data collection. CCRS collected and supplied the level-3s images to BOREAS Information System (BORIS) for use in the remote sensing research activities. Spatially, the level-3s images cover 60- by 60-km portions of the BOREAS Northern Study Area (NSA) and Southern Study Area (SSA). Temporally, the images cover the period of 17-Apr-1994 to 30-Aug-1996. The images are available in binary image format files. Due to copyright issues, the SPOT images may not be publicly available.

Developing Land Surface Type Map with Biome Classification Scheme Using Suomi NPP/JPSS VIIRS Data

NASA Astrophysics Data System (ADS)

Zhang, Rui; Huang, Chengquan; Zhan, Xiwu; Jin, Huiran

2016-08-01

Accurate representation of actual terrestrial surface types at regional to global scales is an important element for a wide range of applications, such as land surface parameterization, modeling of biogeochemical cycles, and carbon cycle studies. In this study, in order to meet the requirement of the retrieval of global leaf area index (LAI) and fraction of photosynthetically active radiation absorbed by the vegetation (fPAR) and other studies, a global map generated from Suomi National Polar- orbiting Partnership (S-NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) surface reflectance data in six major biome classes based on their canopy structures, which include: Grass/Cereal Crops, Shrubs, Broadleaf Crops, Savannas, Broadleaf Forests, and Needleleaf Forests, was created. The primary biome classes were converted from an International Geosphere-Biosphere Program (IGBP) legend global surface type data that was created in previous study, and the separation of two crop types are based on a secondary classification.

Automatic monitoring of ecosystem structure and functions using integrated low-cost near surface sensors

NASA Astrophysics Data System (ADS)

Kim, J.; Ryu, Y.; Jiang, C.; Hwang, Y.

2016-12-01

Near surface sensors are able to acquire more reliable and detailed information with higher temporal resolution than satellite observations. Conventional near surface sensors usually work individually, and thus they require considerable manpower from data collection through information extraction and sharing. Recent advances of Internet of Things (IoT) provides unprecedented opportunities to integrate various low-cost sensors as an intelligent near surface observation system for monitoring ecosystem structure and functions. In this study, we developed a Smart Surface Sensing System (4S), which can automatically collect, transfer, process and analyze data, and then publish time series results on public-available website. The system is composed of micro-computer Raspberry pi, micro-controller Arduino, multi-spectral spectrometers made from Light Emitting Diode (LED), visible and near infrared cameras, and Internet module. All components are connected with each other and Raspberry pi intelligently controls the automatic data production chain. We did intensive tests and calibrations in-lab. Then, we conducted in-situ observations at a rice paddy field and a deciduous broadleaf forest. During the whole growth season, 4S obtained landscape images, spectral reflectance in red, green, blue, and near infrared, normalized difference vegetation index (NDVI), fraction of photosynthetically active radiation (fPAR), and leaf area index (LAI) continuously. Also We compared 4S data with other independent measurements. NDVI obtained from 4S agreed well with Jaz hyperspectrometer at both diurnal and seasonal scales (R2 = 0.92, RMSE = 0.059), and 4S derived fPAR and LAI were comparable to LAI-2200 and destructive measurements in both magnitude and seasonal trajectory. We believe that the integrated low-cost near surface sensor could help research community monitoring ecosystem structure and functions closer and easier through a network system.

78 FR 48679 - Agency Information Collection Activities; Submission to OMB for Review and Approval; Public...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-09

... (GPRA) and HHS, to guide financial and program planning and evaluation, and to respond to inquiries... identifier HHS-OS-19606-30D for reference. Information Collection Request Title: Family Planning Annual...) administers and oversees the Title X Family Planning Program. The Family Planning Annual Report (FPAR) is an...

78 FR 29370 - Agency Information Collection Activities; Proposed Collection; Public Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-20

... HHS, to guide financial and program planning and evaluation, and to respond to inquiries about the... identifier HHS-OS-19606-60D for reference. Information Collection Request Title: Family Planning Annual...) administers and oversees the Title X Family Planning Program. The Family Planning Annual Report (FPAR) is an...

Simulating Carbon Flux Dynamics with the Product of PAR Absorbed by Chlorophyll (fAPARchl)

NASA Astrophysics Data System (ADS)

Yao, T.; Zhang, Q.

2016-12-01

A common way to estimate the gross primary production (GPP) is to use the fraction of photosynthetically radiation (PAR) absorbed by vegetation (FPAR). However, only the PAR absorbed by chlorophyll of the canopy, not the PAR absorbed by the foliage or by the entire canopy, is used for photosynthesis. MODIS fAPARchl product, which refers to the fraction of PAR absorbed by chlorophyll of the canopy, is derived from Moderate Resolution Imaging Spectroradiometer (MODIS) surface reflectance by using an advanced leaf-canopy-soil-water-snow coupled radiative transfer model PROSAIL4. PROSAIL4 can retrieve surface water cover fraction, snow cover fraction, and physiologically active canopy chemistry components (chlorophyll concentration and water content), fraction of photosynthetically active radiation (PAR) absorbed by a canopy (fAPARcanopy), fraction of PAR absorbed by photosynthetic vegetation (PV) component (mainly chlorophyll) throughout the canopy (fAPARPV, i.e., fAPARchl) and fraction of PAR absorbed by non-photosynthetic vegetation (NPV) component of the canopy (fAPARNPV). We have successfully retrieved these vegetation parameters for selected areas with PROSAIL4 and the MODIS images, or simulated spectrally MODIS-like images. In this study, the product of PAR absorbed by chlorophyll (fAPARchl) has been used to simulate carbon flux over different kinds of vegetation types. The results show that MODIS fAPARchl product has the ability to better characterize phenology than current phenology model in the Community Land Model and it also will likely be able to increase the accuracy of carbon fluxes simulations.

Mid Term Progress Report: Desertification Assessment and Monitoring in China Based on Remote Sensing

NASA Astrophysics Data System (ADS)

Gao, Zhihai; del Barrio, Gabriel; Li, Xiaosong; Wang, Bengyu; Puigdefabregas, Juan; Sanjuan, Maria E.; Bai, Lina; Wu, Junjun; Sun, Bin; Li, Changlong

2014-11-01

The objective of Dragon 3 Project 10367 is the development of techniques research for desertification assessment and monitoring in China using remote sensing data in combination with climate and environmental-related data. The main achievements acquired since2012could be summarized as follows: (1)Photosynthetic vegetation(PV)and non-photosynthetic vegetation(NPV)fraction were retrieved separately through utilizing Auto Monte Carlo Unmixing technique (AutoMCU), based on BJ-1 data and field measured spectral library. (2) The accuracy of sandy land classification was as high as81.52%when the object-oriented method and Support Vector Machine (SVM) classifiers were used. (3) A new Monthly net primary productivity (NPP)dataset from 2002 to 2010 for the whole China were established with Envisat-MERIS fraction of absorbed photosynthetically active radiation (FPAR) data. (4) The 2dRUE proved to be a good indicator for land degradation, based on which, land degradation status in the general potential extent of desertification in China(PEDC) was assessed preliminarily.

Mid Term Progress Report: Desertification Assessment and Monitoring in China Based on Remote Sensing

NASA Astrophysics Data System (ADS)

Gao, Zhihai; del Barrio, Gabriel; Li, Xiaosong; Wang, Wengyu; Puigdefabregas, Juan; Sanjuan, Maria E.; Bai, Lina; Wu, Junjun; Sun, Bin; Li, Changlong

2014-11-01

The objective of Dragon 3 Project 10367 is the development of techniques research for desertification assessment and monitoring in China using remote sensing data in combination with climate and environmental-related data. The main achievements acquired since 2012 could be summarized as follows:(1) Photosynthetic vegetation (PV) and non-photosynthetic vegetation (NPV) fraction were retrieved separately through utilizing Auto Monte Carlo Unmixing technique (AutoMCU), based on BJ-1 data and field measured spectral library.(2) The accuracy of sandy land classification was as high as 81.52% when the object-oriented method and Support Vector Machine (SVM) classifiers were used.(3) A new Monthly net primary productivity (NPP) dataset from 2002 to 2010 for the whole China were established with Envisat-MERIS fraction of absorbed photosynthetically active radiation (FPAR) data.(4) The 2dRUE proved to be a good indicator for land degradation, based on which, land degradation status in the general potential extent of desertification in China (PEDC) was assessed preliminarily.

BOREAS Level-3p Landsat TM Imagery: Geocoded and Scaled At-sensor Radiance

NASA Technical Reports Server (NTRS)

Nickeson, Jaime; Knapp, David; Newcomer, Jeffrey A.; Hall, Forrest G. (Editor); Cihlar, Josef

2000-01-01

For BOReal Ecosystem-Atmosphere Study (BOREAS), the level-3p Landsat Thematic Mapper (TM) data were used to supplement the level-3s Landsat TM products. Along with the other remotely sensed images, the Landsat TM images were collected in order to provide spatially extensive information over the primary study areas. This information includes radiant energy, detailed land cover, and biophysical parameter maps such as Fraction of Photosynthetically Active Radiation (FPAR) and Leaf Area Index (LAI). Although very similar to the level-3s Landsat TM products, the level-3p images were processed with ground control information, which improved the accuracy of the geographic coordinates provided. Geographically, the level-3p images cover the BOREAS Northern Study Area (NSA) and Southern Study Area (SSA). Temporally, the four images cover the period of 20-Aug-1988 to 07-Jun-1994. Except for the 07-Jun-1994 image, which contains seven bands, the other three contain only three bands.

Higher absorbed solar radiation partly offset the negative effects of water stress on the photosynthesis of Amazon forests during the 2015 drought

NASA Astrophysics Data System (ADS)

Li, Xing; Xiao, Jingfeng; He, Binbin

2018-04-01

Amazon forests play an important role in the global carbon cycle and Earth’s climate. The vulnerability of Amazon forests to drought remains highly controversial. Here we examine the impacts of the 2015 drought on the photosynthesis of Amazon forests to understand how solar radiation and precipitation jointly control forest photosynthesis during the severe drought. We use a variety of gridded vegetation and climate datasets, including solar-induced chlorophyll fluorescence (SIF), photosynthetic active radiation (PAR), the fraction of absorbed PAR (APAR), leaf area index (LAI), precipitation, soil moisture, cloud cover, and vapor pressure deficit (VPD) in our analysis. Satellite-derived SIF observations provide a direct diagnosis of plant photosynthesis from space. The decomposition of SIF to SIF yield (SIFyield) and APAR (the product of PAR and fPAR) reveals the relative effects of precipitation and solar radiation on photosynthesis. We found that the drought significantly reduced SIFyield, the emitted SIF per photon absorbed. The higher APAR resulting from lower cloud cover and higher LAI partly offset the negative effects of water stress on the photosynthesis of Amazon forests, leading to a smaller reduction in SIF than in SIFyield and precipitation. We further found that SIFyield anomalies were more sensitive to precipitation and VPD anomalies in the southern regions of the Amazon than in the central and northern regions. Our findings shed light on the relative and combined effects of precipitation and solar radiation on photosynthesis, and can improve our understanding of the responses of Amazon forests to drought.

Spatially explicit modelling of forest structure and function using airborne lidar and hyperspectral remote sensing data combined with micrometeorological measurements

NASA Astrophysics Data System (ADS)

Thomas, Valerie Anne

This research models canopy-scale photosynthesis at the Groundhog River Flux Site through the integration of high-resolution airborne remote sensing data and micrometeorological measurements collected from a flux tower. Light detection and ranging (lidar) data are analysed to derive models of tree structure, including: canopy height, basal area, crown closure, and average aboveground biomass. Lidar and hyperspectral remote sensing data are used to model canopy chlorophyll (Chl) and carotenoid concentrations (known to be good indicators of photosynthesis). The integration of lidar and hyperspectral data is applied to derive spatially explicit models of the fraction of photosynthetically active radiation (fPAR) absorbed by the canopy as well as a species classification for the site. These products are integrated with flux tower meteorological measurements (i.e., air temperature and global solar radiation) collected on a continuous basis over 2004 to apply the C-Fix model of carbon exchange to the site. Results demonstrate that high resolution lidar and lidar-hyperspectral integration techniques perform well in the boreal mixedwood environment. Lidar models are well correlated with forest structure, despite the complexities introduced in the mixedwood case (e.g., r2=0.84, 0.89, 0.60, and 0.91, for mean dominant height, basal area, crown closure, and average aboveground biomass). Strong relationships are also shown for canopy scale chlorophyll/carotenoid concentration analysis using integrated lidar-hyperspectral techniques (e.g., r2=0.84, 0.84, and 0.82 for Chl(a), Chl(a+b), and Chl(b)). Examination of the spatially explicit models of fPAR reveal distinct spatial patterns which become increasingly apparent throughout the season due to the variation in species groupings (and canopy chlorophyll concentration) within the 1 km radius surrounding the flux tower. Comparison of results from the modified local-scale version of the C-Fix model to tower gross ecosystem productivity (GEP) demonstrate a good correlation to flux tower measured GEP (r2=0.70 for 10 day averages), with the largest deviations occurring in June-July. This research has direct benefits for forest inventory mapping and management practices; mapping of canopy physiology and biochemical constituents related to forest health; and scaling and direct comparison to large resolution satellite models to help bridge the gap between the local-scale measurements at flux towers and predictions derived from continental-scale carbon models.

A Model-based Approach to Scaling GPP and NPP in Support of MODIS Land Product Validation

NASA Astrophysics Data System (ADS)

Turner, D. P.; Cohen, W. B.; Gower, S. T.; Ritts, W. D.

2003-12-01

Global products from the Earth-orbiting MODIS sensor include land cover, leaf area index (LAI), FPAR, 8-day gross primary production (GPP), and annual net primary production (NPP) at the 1 km spatial resolution. The BigFoot Project was designed specifically to validate MODIS land products, and has initiated ground measurements at 9 sites representing a wide array of vegetation types. An ecosystem process model (Biome-BGC) is used to generate estimates of GPP and NPP for each 5 km x 5 km BigFoot site. Model inputs include land cover and LAI (from Landsat ETM+), daily meteorological data (from a centrally located eddy covariance flux tower), and soil characteristics. Model derived outputs are validated against field-measured NPP and flux tower-derived GPP. The resulting GPP and NPP estimates are then aggregated to the 1 km resolution for direct spatial comparison with corresponding MODIS products. At the high latitude sites (tundra and boreal forest), the MODIS GPP phenology closely tracks the BigFoot GPP, but there is a high bias in the MODIS GPP. In the temperate zone sites, problems with the timing and magnitude of the MODIS FPAR introduce differences in MODIS GPP compared to the validation data at some sites. However, the MODIS LAI/FPAR data are currently being reprocessed (=Collection 4) and new comparisons will be made for 2002. The BigFoot scaling approach permits precise overlap in spatial and temporal resolution between the MODIS products and BigFoot products, and thus permits the evaluation of specific components of the MODIS NPP algorithm. These components include meteorological inputs from the NASA Data Assimilation Office, LAI and FPAR from other MODIS algorithms, and biome-specific parameters for base respiration rate and light use efficiency.

BOREAS RSS-4 1994 Southern Study Area Jack Pine LAI and FPAR Data

NASA Technical Reports Server (NTRS)

Hall, Forrest G. (Editor); Nickeson, Jaime (Editor); Plummer, Stephen

2000-01-01

The RSS-4 team collected several data sets related to leaf, plant, and stand physical, optical, and chemical properties. This data set contains leaf area indices and FPAR measurements that were taken at the three conifer sites in the BOREAS SSA during August 1993 and at the jack pine tower flux and a subset of auxiliary sites during July and August 1994. The measurements were made with LAI-2000 and Ceptometer instruments. The measurements were taken for the purpose of model parameterization and to test empirical relationships that were hypothesized between biophysical parameters and remotely sensed data. The data are stored in tabular ASCII files.

Examining the Influence of Teleconnection Patterns on CO2 Fluxes at an Old-Growth Forest Scaling from Stand to Region Using MODIS

NASA Astrophysics Data System (ADS)

Wharton, S.; Chasmer, L.; Falk, M.; Paw U, K.

2007-12-01

In this study, year-to-year variability in three of the major Pacific teleconnection patterns were examined to determine if CO2 and H2O fluxes at an old-growth forest in the Pacific Northwest were affected by climatic changes associated with these patterns. The three cycles examined are the Pacific Decadal Oscillation, Pacific/North American Oscillation and El Niño-Southern Oscillation. We centered our study on the Wind River Canopy Crane, an AmeriFlux tower located in a 500 year old conifer forest in southern Washington State. CO2 and H2O fluxes have been measured continuously for six years using the eddy covariance method. The objectives of this study are to: 1. determine to what extent teleconnection patterns influence measured CO2 and H2O fluxes through mechanistic anomalies; 2. ascertain if climatic shifts affect annual vegetation canopy characteristics; and 3. make comparisons at the local and regional scales using MODIS. The ecosystem was a significant sink of carbon (-207 gC m-2 year-1) in 1999 but turned into a large carbon source (+ 100 gC m-2 year-1) in 2003. NEE significantly (above the 95th CI) lags the PNA, ENSO and PDO indicating that these patterns affect the forest carbon budget across overlapping time scales. To ascertain the influence of atmospheric patterns on fluxes, we categorized the flux measurement years based on in-phase climate events (1999 = La Niña/cool PDO, 2003 = El Niño/warm PDO, 2000-2002, 2004 = neutral ENSO years). The results of this analysis indicate that the Pacific Ocean/atmospheric oscillation anomalies explain much of variance in annual NEE (R2 = 0.78 between NEE and the PDO, R2 = 0.87 for the PNA, and R2 = 0.56 for ENSO). Teleconnection patterns are found to be associated mostly with air temperature, precipitation, and incoming light radiation (cloudy vs. sunny conditions). Important meteorological driving mechanisms of fluxes include: water- use efficiency (WUE), light-use efficiency (LUE) and canopy structure parameters (e.g., fPAR). Tower-based fPAR was strongly related to NEE (R2 = 0.78) and climatic patterns (R2 = 0.84 with ENSO and R2 = 0.76 with PDO). Variability in fluxes may be a result of changes in the canopy structural characteristics; for example higher, fPAR (e.g., 2003) correlated well with increased respiration fluxes. MODIS data (200 km X 200 km area) were obtained to determine if anomalies in vegetation indices and canopy structure could be linked to teleconnection patterns at the site level and across the region. The MODIS-derived Enhanced Vegetation Index (EVI) correlated well with yearly cumulative NEE at the tower and regional EVI anomalies were strongly negatively correlated with the annual PDO index (R2 = 0.9). MODIS-derived fPAR product correlated with yearly variability in the PDO (R2 = 0.34) at the site level. Therefore, there is reasonable expectation that structural changes, as a result of climate variability during strongly positive or negative teleconnection patterns, will be observed in other parts of the Pacific Northwest. MODIS data is useful for identifying the effects of teleconnections across a regional scale.

Characterization of extreme years in Central Europe between 2000 and 2016 according to specific vegetation characteristics based on Earth Observatory data

NASA Astrophysics Data System (ADS)

Kern, Anikó; Marjanović, Hrvoje; Barcza, Zoltán

2017-04-01

Extreme weather events frequently occur in Central Europe, affecting the state of the vegetation in large areas. Droughts and heat-waves affect all plant functional types, but the response of the vegetation is not uniform and depends on other parameters, plant strategies and the antecedent meteorological conditions as well. Meteorologists struggle with the definition of extreme events and selection of years that can be considered as extreme in terms of meteorological conditions due to the large variability of the meteorological parameters both in time and space. One way to overcome this problem is the definition of extreme weather based on its observed effect on plant state. The Normalized Difference Vegetation Index (NDVI), the Enhanced Vegetation Index (EVI), the Leaf Area Index (LAI), the Fraction of Photosynthetically Active Radiation (FPAR) and the Gross Primary Production (GPP) are different measures of the land vegetation derived from remote sensing data, providing information about the plant state, but it is less known how weather anomalies affect these measures. We used the vegetation related official products created from the measurements of the MODerate resolution Imaging Spectroradiometer (MODIS) on board satellite Terra to select and characterize the extreme years in Central European countries during the 2000-2016 time period. The applied Collection-6 MOD13 NDVI/EVI, MOD15 LAI/FPAR and MOD17 GPP datasets have 500 m × 500 m spatial resolution covering the region of the Carpathian-Basin. After quality and noise filtering (and temporal interpolation in case of MOD13) 8-day anomaly values were derived to investigate the different years. The freely available FORESEE meteorological database was used to study climate variability in the region. Daily precipitation and maximum/minimum temperature fields at 1/12° × 1/12° grid were resampled to the 8-day temporal and 500 m × 500 m spatial resolution of the MODIS products. To discriminate the different behavior of the various plant functional types MODIS (MCD12) and CORINE (CLC2012) land cover datasets were applied and handled together. Based on the determination of the reliable pixels with different plant types the response of broadleaf forests, coniferous forests, grasslands and croplands were discriminated and investigated. Characteristic time periods were selected based on the remote sensing data to define anomalies, and then the meteorological data were used to define critical time periods within the year that has the strongest effect on the observed anomalies. Similarities/dissimilarities between the behaviors of the different remotely sensed measures are also studied to elucidate the consistency of the indices. The results indicate that the diverse remote sensing indices typically co-vary but reveal strong plant functional type dependency. The study suggest that the selection of extreme years based on annual data is not the best choice, as shorter time periods within the years explain the anomalies to a higher degree than annual data. The results can be used to select anomalous years outside of the satellite era as well. Keywords: Remote sensing, meteorology; extreme years; MODIS, NDVI; EVI; LAI; FPAR; GPP; phenology

Predicting the Invasion Potential of a Puerto Rican Frog in Hawaii using MODIS Satellite Imagery

NASA Astrophysics Data System (ADS)

Bisrat, S. A.; White, M. A.

2008-12-01

The Puerto Rican coqui frog (Eleutherodactylus coqui, hereafter coqui), which was introduced into Hawaii accidentally via commercial nurseries, is an aggressive invasive species in Hawaii. The coqui threatens Hawaii's unique ecological communities because it predates upon endemic invertebrates, which comprise the large majority of Hawaii's endemic fauna. Coqui frogs also affect real estate valuations because of their loud mating calls. Despite this widespread problem, the potential coqui range in Hawaii is currently unknown, making control and management efforts difficult. We fitted linear discriminant analysis (LDA), logistic regression (LR) via generalized linear models (GLMs), generalized additive models (GAMs), classification trees (CTs), random forests (RF), and support vector machine (SVM) to model the species distribution and map their invasion potential. We used five MODIS satellite imagery-derived biophysical variables as explanatory variables: leaf area index (LAI), fraction of photosynthetically active radiation absorbed by vegetation (FPAR), enhanced vegetation index (EVI), normalized difference vegetation index (NDVI), and land surface temperature (LST) from three MODIS products: MOD11 (LST), MOD13 (LAI and FPAR), and MOD15 (Vegetation Index) (collection 4). We used 2000-2005 MODIS data from Aqua and Terra satellites to generate monthly climatologies for each biophysical variable. We collected presence/absence data from Puerto Rico and Hawaii using a 1 km grid overlaid over the entire islands of Puerto Rico and the Island of Hawaii by sampling every other pixel of the grid intersecting with the road network. We then used the dataset from Puerto Rico to train the six models while the Hawaii dataset was used as a test set. All six models predicted the invasion potential of coqui frogs in Hawaii with a moderate success with mean Kappa value of 0.31, mean area under the curve of receiver operating characteristics (AUC) of 0.75 and mean classification accuracy (CA) of 0.69. RF and SVM outperformed the other classifiers with Kappa value of 0.4, AUC value of 0.79 and CA of 0.71 for RF and Kappa value of 0.4, AUC value of 0.71 and CA value of 0.72 for SVM. These results suggest climate matching between the native and the introduced habitats of coqui frogs is not strong. Further, the results suggest coqui frogs in their introduced habitat are not showing strong niche conservation.

A comprehensive assessment of the correlations between field crop yields and commonly used MODIS products

NASA Astrophysics Data System (ADS)

Johnson, David M.

2016-10-01

An exploratory assessment was undertaken to determine the correlation strength and optimal timing of several commonly used Moderate Resolution Imaging Spectroradiometer (MODIS) composited imagery products against crop yields for 10 globally significant agricultural commodities. The crops analyzed included barley, canola, corn, cotton, potatoes, rice, sorghum, soybeans, sugarbeets, and wheat. The MODIS data investigated included the Normalized Difference Vegetation Index (NDVI), Fraction of Photosynthetically Active Radiation (FPAR), Leaf Area Index (LAI), and Gross Primary Production (GPP), in addition to daytime Land Surface Temperature (DLST) and nighttime LST (NLST). The imagery utilized all had 8-day time intervals, but NDVI had a 250 m spatial resolution while the other products were 1000 m. These MODIS datasets were also assessed from both the Terra and Aqua satellites, with their differing overpass times, to document any differences. A follow-on analysis, using the Terra 250 m NDVI data as a benchmark, looked at the yield prediction utility of NDVI at two spatial scales (250 m vs. 1000 m), two time precisions (8-day vs. 16-day), and also assessed the Enhanced Vegetation Index (EVI, at 250 m, 16-day). The analyses spanned the major farming areas of the United States (US) from the summers of 2008-2013 and used annual county-level average crop yield data from the US Department of Agriculture as a basis. All crops, except rice, showed at least some positive correlations to each of the vegetation related indices in the middle of the growing season, with NDVI performing slightly better than FPAR. LAI was somewhat less strongly correlated and GPP weak overall. Conversely, some of the crops, particularly canola, corn, and soybeans, also showed negative correlations to DLST mid-summer. NLST, however, was never correlated to crop yield, regardless of the crop or seasonal timing. Differences between the Terra and Aqua results were found to be minimal. The 1000 m resolution NDVI showed somewhat poorer performance than the 250 m and suggests spatial resolution is helpful but not a necessity. The 8-day versus 16-day NDVI relationships to yields were very similar other than for the temporal precision. Finally, the EVI often showed the very best performance of all the variables, all things considered.

DSCOVR EPIC L2 VESDR Data Release Announcement

Atmospheric Science Data Center

2018-06-14

... Polychromatic Imaging Camera (EPIC) onboard the Deep Space Climate Observatory (DSCOVR). The VESDR product contains Leaf Area Index (LAI) ... FPAR, LAI, SLAI are useful for monitoring variability and change in global vegetation due to climate and anthropogenic influences, ...

DSCOVR EPIC L2 VESDR Data Release Announcement

Atmospheric Science Data Center

2018-06-07

... Polychromatic Imaging Camera (EPIC) onboard the Deep Space Climate Observatory (DSCOVR). The VESDR product contains Leaf Area Index (LAI) ... FPAR, LAI, SLAI are useful for monitoring variability and change in global vegetation due to climate and anthropogenic influences, ...

Modelling Biophysical Parameters of Maize Using Landsat 8 Time Series

NASA Astrophysics Data System (ADS)

Dahms, Thorsten; Seissiger, Sylvia; Conrad, Christopher; Borg, Erik

2016-06-01

Open and free access to multi-frequent high-resolution data (e.g. Sentinel - 2) will fortify agricultural applications based on satellite data. The temporal and spatial resolution of these remote sensing datasets directly affects the applicability of remote sensing methods, for instance a robust retrieving of biophysical parameters over the entire growing season with very high geometric resolution. In this study we use machine learning methods to predict biophysical parameters, namely the fraction of absorbed photosynthetic radiation (FPAR), the leaf area index (LAI) and the chlorophyll content, from high resolution remote sensing. 30 Landsat 8 OLI scenes were available in our study region in Mecklenburg-Western Pomerania, Germany. In-situ data were weekly to bi-weekly collected on 18 maize plots throughout the summer season 2015. The study aims at an optimized prediction of biophysical parameters and the identification of the best explaining spectral bands and vegetation indices. For this purpose, we used the entire in-situ dataset from 24.03.2015 to 15.10.2015. Random forest and conditional inference forests were used because of their explicit strong exploratory and predictive character. Variable importance measures allowed for analysing the relation between the biophysical parameters with respect to the spectral response, and the performance of the two approaches over the plant stock evolvement. Classical random forest regression outreached the performance of conditional inference forests, in particular when modelling the biophysical parameters over the entire growing period. For example, modelling biophysical parameters of maize for the entire vegetation period using random forests yielded: FPAR: R² = 0.85; RMSE = 0.11; LAI: R² = 0.64; RMSE = 0.9 and chlorophyll content (SPAD): R² = 0.80; RMSE=4.9. Our results demonstrate the great potential in using machine-learning methods for the interpretation of long-term multi-frequent remote sensing datasets to model biophysical parameters.

Application and Evaluation of MODIS LAI, FPAR, and Albedo Products in the WRF/CMAQ System

EPA Science Inventory

MODIS vegetation and albedo products provide a more realistic representation of surface conditions for input to the WRF/CMAQ modeling system. However, the initial evaluation of ingesting MODIS data into the system showed mixed results, with increased bias and error for 2-m temper...

75 FR 66101 - Agency Information Collection Request. 30-Day Public Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-27

... DEPARTMENT OF HEALTH AND HUMAN SERVICES [Document Identifier: OS-0990-0221; 30-day notice] Agency... of the Secretary (OS), Department of Health and Human Services, is publishing the following summary... public and private non-profit public heath agencies. OPA uses FPAR data to monitor compliance with...

Assessment of MODIS-EVI, MODIS-NDVI and VEGETATION-NDVI composite data using agricultural measurements: an example at corn fields in western Mexico.

PubMed

Chen, Pei-Yu; Fedosejevs, Gunar; Tiscareño-López, Mario; Arnold, Jeffrey G

2006-08-01

Although several types of satellite data provide temporal information of the land use at no cost, digital satellite data applications for agricultural studies are limited compared to applications for forest management. This study assessed the suitability of vegetation indices derived from the TERRA-Moderate Resolution Imaging Spectroradiometer (MODIS) sensor and SPOT-VEGETATION (VGT) sensor for identifying corn growth in western Mexico. Overall, the Normalized Difference Vegetation Index (NDVI) composites from the VGT sensor based on bi-directional compositing method produced vegetation information most closely resembling actual crop conditions. The NDVI composites from the MODIS sensor exhibited saturated signals starting 30 days after planting, but corresponded to green leaf senescence in April. The temporal NDVI composites from the VGT sensor based on the maximum value method had a maximum plateau for 80 days, which masked the important crop transformation from vegetative stage to reproductive stage. The Enhanced Vegetation Index (EVI) composites from the MODIS sensor reached a maximum plateau 40 days earlier than the occurrence of maximum leaf area index (LAI) and maximum intercepted fraction of photosynthetic active radiation (fPAR) derived from in-situ measurements. The results of this study showed that the 250-m resolution MODIS data did not provide more accurate vegetation information for corn growth description than the 500-m and 1000-m resolution MODIS data.

Is There an "F" in Your PAR? Understanding, Teaching and Doing Action Research

ERIC Educational Resources Information Center

Lorenzetti, Liza; Walsh, Christine Ann

2014-01-01

Participatory Action Research (PAR) is increasingly recognized within academic research and pedagogy. What are the benefits of including feminism within participatory action research and teaching? In responding to this question, we discuss the similarities and salient differences between PAR and feminist informed PAR (FPAR). There are eight themes…

Application and Evaluation of MODIS LAI, fPAR, and Albedo Products in the WRFCMAQ System

EPA Science Inventory

Leaf area index (LAI), vegetation fraction (VF), and surface albedo are important parameters in the land surface model (LSM) for meteorology and air quality modeling systems such as WRF/CMAQ. LAI and VF control not only leaf to canopy level evapotranspiration flux scaling but al...

Recent changes and relations among drought, vegetation and wildfires in the Eastern Mediterranean: The case of Israel

NASA Astrophysics Data System (ADS)

Turco, Marco; Levin, Noam; Tessler, Naama; Saaroni, Hadas

2017-04-01

On-going changes in drought, vegetation and wildfires in Israel provide a key example of possible future evolution in transition areas at the border between Mediterranean and arid climates. Here we present multiple lines of evidence suggesting that drought conditions in Israel, representing the eastern Mediterranean, have increased during the period 1980-2014. Drought conditions were calculated using the Standardized Precipitation Evapotranspiration Index (SPEI), the Standardized Precipitation Index (SPI) and the Standardized Soil Moisture Index (SSI). A 30-year series (1982-2011) of monthly Fraction of Photosynthetically Active Radiation absorbed by vegetation (FPAR) indicates generally positive trends in winter and spring and negative ones in summer and autumn, except in the transition zone between the southern Negev desert and the Mediterranean climate region, where a statistically significant negative trend in all seasons was found. Available ground observations suggest that fire activity has decreased during the period 1987-2011. Apparent year-to-year oscillations are superposed onto these long-term trends. We show that inter-annual variability of summer fires is related to antecedent wet conditions and to above normal vegetation conditions. These relationships suggest the summer fires in Israel are mainly limited by fuel availability rather than by fuel flammability. On the other hand, the year-to-year variations of spring and autumn fires are significantly related with drought indices. Thus, the increase of drought conditions together with climate projections for further warming and drying in this region, point at a potential increase of fire risk in the intermediate seasons.

GEONEX: Land Monitoring From a New Generation of Geostationary Satellite Sensors

NASA Technical Reports Server (NTRS)

Nemani, Ramakrishna; Lyapustin, Alexei; Wang, Weile; Wang, Yujie; Hashimoto, Hirofumi; Li, Shuang; Ganguly, Sangram; Michaelis, Andrew; Higuchi, Atsushi; Takaneka, Hideaki;

GEONEX: Land monitoring from a new generation of geostationary satellite sensors

NASA Astrophysics Data System (ADS)

Nemani, R. R.; Lyapustin, A.; Wang, W.; Ganguly, S.; Wang, Y.; Michaelis, A.; Hashimoto, H.; Li, S.; Higuchi, A.; Huete, A. R.; Yeom, J. M.; camacho De Coca, F.; Lee, T. J.; Takenaka, H.

2017-12-01

The latest generation of geostationary satellites carry sensors such as ABI (Advanced Baseline Imager on GOES-16) and the AHI (Advanced Himawari Imager on Himawari) that closely mimic the spatial and spectral characteristics of Earth Observing System flagship MODIS for monitoring land surface conditions. More importantly they provide observations at 5-15 minute intervals. Such high frequency data offer exciting possibilities for producing robust estimates of land surface conditions by overcoming cloud cover, enabling studies of diurnally varying local-to-regional biosphere-atmosphere interactions, and operational decision-making in agriculture, forestry and disaster management. But the data come with challenges that need special attention. For instance, geostationary data feature changing sun angle at constant view for each pixel, which is reciprocal to sun-synchronous observations, and thus require careful adaptation of EOS algorithms. Our goal is to produce a set of land surface products from geostationary sensors by leveraging NASA's investments in EOS algorithms and in the data/compute facility NEX. The land surface variables of interest include atmospherically corrected surface reflectances, snow cover, vegetation indices and leaf area index (LAI)/fraction of photosynthetically absorbed radiation (FPAR), as well as land surface temperature and fires. In order to get ready to produce operational products over the US from GOES-16 starting 2018, we have utilized 18 months of data from Himawari AHI over Australia to test the production pipeline and the performance of various algorithms for our initial tests. The end-to-end processing pipeline consists of a suite of modules to (a) perform calibration and automatic georeference correction of the AHI L1b data, (b) adopt the Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithm to produce surface spectral reflectances along with compositing schemes and QA, and (c) modify relevant EOS retrieval algorithms (e.g., LAI and FPAR, GPP, etc.) for subsequent science product generation. Initial evaluation of Himawari AHI products against standard MODIS products indicate general agreement, suggesting that data from geostationary sensors can augment low earth orbit (LEO) satellite observations.

BOREAS Level-0 NS001 TMS Imagery: Digital Counts in BIL Format

NASA Technical Reports Server (NTRS)

Hall, Forrest G. (Editor); Newcomer, Jeffrey A.; Dominguez, Roseanne

2000-01-01

For BOREAS, the NS001 TMS imagery, along with the other remotely sensed images, was collected in order to provide spatially extensive information over the primary study areas. This information includes detailed land cover and biophysical parameter maps such as fPAR and LAI. Data collections occurred over the study areas during the 1994 field campaigns.

Evaluation of eco-physiological indicators in Northeast Asia dryland regions based on MODIS products and ecological models

NASA Astrophysics Data System (ADS)

Kang, W.

2017-12-01

Ecosystem carbon-energy-water circles have significant effect on function and structure and vice verse. Based on these circles mechanism, some eco-physiological indicators, like Transpiration (T), gross primary productivity (GPP), light use efficiency (LUE) and water use efficiency (WUE), are commonly applied to assess terrestrial ecosystem function and structure dynamics. The ecosystem weakened function and simple structure in Northeast dryland regions resulted from land degradation or desertification, which could be demonstrated by above-mentioned indicators. In this study, based on MODIS atmosphere (MYD07, MYD04, MYD06 data) and land products (MYD13A2 NDVI, MYD11A1 LST, MYD15A2 LAI and land cover data), we first retrieved transpiration and LUE via Penman-Monteith Model and modified Vegetation Photosynthesis Model (VPM), respectively; and then evaluated dynamics of these eco-physiological indicators (Tair, VPD, T, LUE, GPP and WUE) and some hotspots were found for next land degradation assessment. The results showed: (1) LUE and WUE are lower in barren or sparsely vegetated area and grasslands than in forest and croplands. (2) Whereas, all indicators presented higher variability in grassland area, particularly in east Mongolia. (3) GPP and transpiration have larger variability than other indicators due to fraction of absorbed Photosynthetically active radiation (FPAR). These eco-physiological indicators are expected to continue to change under future climate change and to help to assess land degradation from ecosystem energy-water-carbon perspectives.

Estimation of leaf area index and its sunlit portion from DSCOVR EPIC data: Theoretical basis

PubMed Central

Yang, Bin; Knyazikhin, Yuri; Mõttus, Matti; Rautiainen, Miina; Stenberg, Pauline; Yan, Lei; Chen, Chi; Yan, Kai; Choi, Sungho; Park, Taejin; Myneni, Ranga B.

2017-01-01

This paper presents the theoretical basis of the algorithm designed for the generation of leaf area index and diurnal course of its sunlit portion from NASA’s Earth Polychromatic Imaging Camera (EPIC) onboard NOAA’s Deep Space Climate Observatory (DSCOVR). The Look-up-Table (LUT) approach implemented in the MODIS operational LAI/FPAR algorithm is adopted. The LUT, which is the heart of the approach, has been significantly modified. First, its parameterization incorporates the canopy hot spot phenomenon and recent advances in the theory of canopy spectral invariants. This allows more accurate decoupling of the structural and radiometric components of the measured Bidirectional Reflectance Factor (BRF), improves scaling properties of the LUT and consequently simplifies adjustments of the algorithm for data spatial resolution and spectral band compositions. Second, the stochastic radiative transfer equations are used to generate the LUT for all biome types. The equations naturally account for radiative effects of the three-dimensional canopy structure on the BRF and allow for an accurate discrimination between sunlit and shaded leaf areas. Third, the LUT entries are measurable, i.e., they can be independently derived from both below canopy measurements of the transmitted and above canopy measurements of reflected radiation fields. This feature makes possible direct validation of the LUT, facilitates identification of its deficiencies and development of refinements. Analyses of field data on canopy structure and leaf optics collected at 18 sites in the Hyytiälä forest in southern boreal zone in Finland and hyperspectral images acquired by the EO-1 Hyperion sensor support the theoretical basis. PMID:28867834

Improving the prediction of African savanna vegetation variables using time series of MODIS products

NASA Astrophysics Data System (ADS)

Tsalyuk, Miriam; Kelly, Maggi; Getz, Wayne M.

2017-09-01

African savanna vegetation is subject to extensive degradation as a result of rapid climate and land use change. To better understand these changes detailed assessment of vegetation structure is needed across an extensive spatial scale and at a fine temporal resolution. Applying remote sensing techniques to savanna vegetation is challenging due to sparse cover, high background soil signal, and difficulty to differentiate between spectral signals of bare soil and dry vegetation. In this paper, we attempt to resolve these challenges by analyzing time series of four MODIS Vegetation Products (VPs): Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), Leaf Area Index (LAI), and Fraction of Photosynthetically Active Radiation (FPAR) for Etosha National Park, a semiarid savanna in north-central Namibia. We create models to predict the density, cover, and biomass of the main savanna vegetation forms: grass, shrubs, and trees. To calibrate remote sensing data we developed an extensive and relatively rapid field methodology and measured herbaceous and woody vegetation during both the dry and wet seasons. We compared the efficacy of the four MODIS-derived VPs in predicting vegetation field measured variables. We then compared the optimal time span of VP time series to predict ground-measured vegetation. We found that Multiyear Partial Least Square Regression (PLSR) models were superior to single year or single date models. Our results show that NDVI-based PLSR models yield robust prediction of tree density (R2 = 0.79, relative Root Mean Square Error, rRMSE = 1.9%) and tree cover (R2 = 0.78, rRMSE = 0.3%). EVI provided the best model for shrub density (R2 = 0.82) and shrub cover (R2 = 0.83), but was only marginally superior over models based on other VPs. FPAR was the best predictor of vegetation biomass of trees (R2 = 0.76), shrubs (R2 = 0.83), and grass (R2 = 0.91). Finally, we addressed an enduring challenge in the remote sensing of semiarid vegetation by examining the transferability of predictive models through space and time. Our results show that models created in the wetter part of Etosha could accurately predict trees' and shrubs' variables in the drier part of the reserve and vice versa. Moreover, our results demonstrate that models created for vegetation variables in the dry season of 2011 could be successfully applied to predict vegetation in the wet season of 2012. We conclude that extensive field data combined with multiyear time series of MODIS vegetation products can produce robust predictive models for multiple vegetation forms in the African savanna. These methods advance the monitoring of savanna vegetation dynamics and contribute to improved management and conservation of these valuable ecosystems.

Validity of Five Satellite-Based Latent Heat Flux Algorithms for Semi-arid Ecosystems

DOE PAGES

Feng, Fei; Chen, Jiquan; Li, Xianglan; ...

2015-12-09

Accurate estimation of latent heat flux (LE) is critical in characterizing semiarid ecosystems. Many LE algorithms have been developed during the past few decades. However, the algorithms have not been directly compared, particularly over global semiarid ecosystems. In this paper, we evaluated the performance of five LE models over semiarid ecosystems such as grassland, shrub, and savanna using the Fluxnet dataset of 68 eddy covariance (EC) sites during the period 2000–2009. We also used a modern-era retrospective analysis for research and applications (MERRA) dataset, the Normalized Difference Vegetation Index (NDVI) and Fractional Photosynthetically Active Radiation (FPAR) from the moderate resolutionmore » imaging spectroradiometer (MODIS) products; the leaf area index (LAI) from the global land surface satellite (GLASS) products; and the digital elevation model (DEM) from shuttle radar topography mission (SRTM30) dataset to generate LE at region scale during the period 2003–2006. The models were the moderate resolution imaging spectroradiometer LE (MOD16) algorithm, revised remote sensing based Penman–Monteith LE algorithm (RRS), the Priestley–Taylor LE algorithm of the Jet Propulsion Laboratory (PT-JPL), the modified satellite-based Priestley–Taylor LE algorithm (MS-PT), and the semi-empirical Penman LE algorithm (UMD). Direct comparison with ground measured LE showed the PT-JPL and MS-PT algorithms had relative high performance over semiarid ecosystems with the coefficient of determination (R2) ranging from 0.6 to 0.8 and root mean squared error (RMSE) of approximately 20 W/m 2. Empirical parameters in the structure algorithms of MOD16 and RRS, and calibrated coefficients of the UMD algorithm may be the cause of the reduced performance of these LE algorithms with R2 ranging from 0.5 to 0.7 and RMSE ranging from 20 to 35 W/m 2 for MOD16, RRS and UMD. Sensitivity analysis showed that radiation and vegetation terms were the dominating variables affecting LE Fluxes in global semiarid ecosystem.« less

Validity of Five Satellite-Based Latent Heat Flux Algorithms for Semi-arid Ecosystems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feng, Fei; Chen, Jiquan; Li, Xianglan

Accurate estimation of latent heat flux (LE) is critical in characterizing semiarid ecosystems. Many LE algorithms have been developed during the past few decades. However, the algorithms have not been directly compared, particularly over global semiarid ecosystems. In this paper, we evaluated the performance of five LE models over semiarid ecosystems such as grassland, shrub, and savanna using the Fluxnet dataset of 68 eddy covariance (EC) sites during the period 2000–2009. We also used a modern-era retrospective analysis for research and applications (MERRA) dataset, the Normalized Difference Vegetation Index (NDVI) and Fractional Photosynthetically Active Radiation (FPAR) from the moderate resolutionmore » imaging spectroradiometer (MODIS) products; the leaf area index (LAI) from the global land surface satellite (GLASS) products; and the digital elevation model (DEM) from shuttle radar topography mission (SRTM30) dataset to generate LE at region scale during the period 2003–2006. The models were the moderate resolution imaging spectroradiometer LE (MOD16) algorithm, revised remote sensing based Penman–Monteith LE algorithm (RRS), the Priestley–Taylor LE algorithm of the Jet Propulsion Laboratory (PT-JPL), the modified satellite-based Priestley–Taylor LE algorithm (MS-PT), and the semi-empirical Penman LE algorithm (UMD). Direct comparison with ground measured LE showed the PT-JPL and MS-PT algorithms had relative high performance over semiarid ecosystems with the coefficient of determination (R2) ranging from 0.6 to 0.8 and root mean squared error (RMSE) of approximately 20 W/m 2. Empirical parameters in the structure algorithms of MOD16 and RRS, and calibrated coefficients of the UMD algorithm may be the cause of the reduced performance of these LE algorithms with R2 ranging from 0.5 to 0.7 and RMSE ranging from 20 to 35 W/m 2 for MOD16, RRS and UMD. Sensitivity analysis showed that radiation and vegetation terms were the dominating variables affecting LE Fluxes in global semiarid ecosystem.« less

Retrieving Biome Types from Multi-angle Spectral Data

NASA Astrophysics Data System (ADS)

Schull, M. A.; Xu, L.; Latorre, P.; Samanta, A.; Myneni, R. B.; Knyazikhin, Y.

2009-12-01

Many studies have been conducted to demonstrate the ability of multi-angle spectral data to discriminate plant dominant species. Most have employed the use of empirically based techniques, which are site specific, requires some initial training based on characteristics of known leaf and/or canopy spectra and therefore may not be extendable to operational use or adapted to changing/unknown land cover. An ancillary objective of the MISR LAI/FPAR algorithm is classification of global vegetation into biome types. The algorithm is based on the 3D radiative transfer equation. Its performance suggests that is has valid LAI retrievals and correct biome identification in about 20% of the pixels. However with a probability of about 70%, uncertainties in LAI retrievals due to biome misclassification do not exceed uncertainties in the observations. In this poster we present an approach to improve reliability of the distribution of biomes and dominant species from multi angle spectral data. The radiative transfer theory of canopy spectral invariants underlies the approach, which facilitates parameterization of the canopy bidirectional reflectance factor in terms of the leaf spectrum and two spectrally invariant and structurally varying variables - recollision and directional escape probabilities. Theoretical and empirical analyses of ground and airborne data acquired by AVIRIS, AirMISR over two sites in New England and CHRIS/PROBA over BARAX site in Spain suggest that the canopy spectral invariants convey information about canopy structure at both the macro and micro scales. These properties allow for the natural separation of biome classes based on the location of points on the total escape probability vs the proportional escape ratio log-log plane.

Deriving a light use efficiency model from eddy covariance flux data for predicting daily gross primary production across biomes

USGS Publications Warehouse

Yuan, W.; Liu, S.; Zhou, G.; Tieszen, L.L.; Baldocchi, D.; Bernhofer, C.; Gholz, H.; Goldstein, Allen H.; Goulden, M.L.; Hollinger, D.Y.; Hu, Y.; Law, B.E.; Stoy, Paul C.; Vesala, T.; Wofsy, S.C.

2007-01-01

The quantitative simulation of gross primary production (GPP) at various spatial and temporal scales has been a major challenge in quantifying the global carbon cycle. We developed a light use efficiency (LUE) daily GPP model from eddy covariance (EC) measurements. The model, called EC-LUE, is driven by only four variables: normalized difference vegetation index (NDVI), photosynthetically active radiation (PAR), air temperature, and the Bowen ratio of sensible to latent heat flux (used to calculate moisture stress). The EC-LUE model relies on two assumptions: First, that the fraction of absorbed PAR (fPAR) is a linear function of NDVI; Second, that the realized light use efficiency, calculated from a biome-independent invariant potential LUE, is controlled by air temperature or soil moisture, whichever is most limiting. The EC-LUE model was calibrated and validated using 24,349 daily GPP estimates derived from 28 eddy covariance flux towers from the AmeriFlux and EuroFlux networks, covering a variety of forests, grasslands and savannas. The model explained 85% and 77% of the observed variations of daily GPP for all the calibration and validation sites, respectively. A comparison with GPP calculated from the Moderate Resolution Imaging Spectroradiometer (MODIS) indicated that the EC-LUE model predicted GPP that better matched tower data across these sites. The realized LUE was predominantly controlled by moisture conditions throughout the growing season, and controlled by temperature only at the beginning and end of the growing season. The EC-LUE model is an alternative approach that makes it possible to map daily GPP over large areas because (1) the potential LUE is invariant across various land cover types and (2) all driving forces of the model can be derived from remote sensing data or existing climate observation networks.

Drought onset mechanisms revealed by satellite solar-induced chlorophyll fluorescence: Insights from two contrasting extreme events

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Ying; Fu, Rong; Dickinson, Robert

This study uses the droughts of 2011 in Texas and 2012 over the central Great Plains as case studies to explore the potential of satellite-observed solar-induced chlorophyll fluorescence (SIF) for monitoring drought dynamics. We find that the spatial patterns of negative SIF anomalies from the Global Ozone Monitoring Experiment 2 (GOME-2) closely resembled drought intensity maps from the U.S. Drought Monitor for both events. The drought-induced suppression of SIF occurred throughout 2011 but was exacerbated in summer in the Texas drought. This event was characterized by a persistent depletion of root zone soil moisture caused by yearlong below-normal precipitation. Inmore » contrast, for the central Great Plains drought, warmer temperatures and relatively normal precipitation boosted SIF in the spring of 2012; however, a sudden drop in precipitation coupled with unusually high temperatures rapidly depleted soil moisture through evapotranspiration, leading to a rapid onset of drought in early summer. Accordingly, SIF reversed from above to below normal. For both regions, the GOME-2 SIF anomalies were significantly correlated with those of root zone soil moisture, indicating that the former can potentially be used as proxy of the latter for monitoring agricultural droughts with different onset mechanisms. Further analyses indicate that the contrasting dynamics of SIF during these two extreme events were caused by changes in both fraction of absorbed photosynthetically active radiation fPAR and fluorescence yield, suggesting that satellite SIF is sensitive to both structural and physiological/biochemical variations of vegetation. Here, we conclude that the emerging satellite SIF has excellent potential for dynamic drought monitoring.« less

Drought onset mechanisms revealed by satellite solar-induced chlorophyll fluorescence: Insights from two contrasting extreme events

DOE PAGES

Sun, Ying; Fu, Rong; Dickinson, Robert; ...

2015-11-02

This study uses the droughts of 2011 in Texas and 2012 over the central Great Plains as case studies to explore the potential of satellite-observed solar-induced chlorophyll fluorescence (SIF) for monitoring drought dynamics. We find that the spatial patterns of negative SIF anomalies from the Global Ozone Monitoring Experiment 2 (GOME-2) closely resembled drought intensity maps from the U.S. Drought Monitor for both events. The drought-induced suppression of SIF occurred throughout 2011 but was exacerbated in summer in the Texas drought. This event was characterized by a persistent depletion of root zone soil moisture caused by yearlong below-normal precipitation. Inmore » contrast, for the central Great Plains drought, warmer temperatures and relatively normal precipitation boosted SIF in the spring of 2012; however, a sudden drop in precipitation coupled with unusually high temperatures rapidly depleted soil moisture through evapotranspiration, leading to a rapid onset of drought in early summer. Accordingly, SIF reversed from above to below normal. For both regions, the GOME-2 SIF anomalies were significantly correlated with those of root zone soil moisture, indicating that the former can potentially be used as proxy of the latter for monitoring agricultural droughts with different onset mechanisms. Further analyses indicate that the contrasting dynamics of SIF during these two extreme events were caused by changes in both fraction of absorbed photosynthetically active radiation fPAR and fluorescence yield, suggesting that satellite SIF is sensitive to both structural and physiological/biochemical variations of vegetation. Here, we conclude that the emerging satellite SIF has excellent potential for dynamic drought monitoring.« less

Comparison of the New LEAF Area INDEX (LAI 3G) with the Kazahstan-Wide LEAF Area INDEX DATA SET (GGRS-LAI) over Central ASIA

NASA Astrophysics Data System (ADS)

Kappas, M.; Propastin, P.; Degener, J.; Renchin, T.

2014-12-01

Long-term global data sets of Leaf Area Index (LAI) are important for monitoring global vegetation dynamics. LAI indicating phenological development of vegetation is an important state variable for modeling land surface processes. The comparison of long-term data sets is based on two recently available data sets both derived from AVHRR time series. The LAI 3g data set introduced by Zaichun Zhu et al. (2013) is developed from the new improved third generation Global Inventory Modeling and Mapping Studies (GIMMS) Normalized Difference Vegetation Index (NDVI3g) and best-quality MODIS LAI data. The second long-term data set is based on the 8 km spatial resolution GIMMS-AVHRR data (GGRS-data set by Propastin et al. 2012). The GGRS-LAI product uses a three-dimensional physical radiative transfer model which establishes relationship between LAI, vegetation fractional cover and given patterns of surface reflectance, view-illumination conditions and optical properties of vegetation. The model incorporates a number of site/region specific parameters, including the vegetation architecture variables such as leaf angle distribution, clumping index, and light extinction coefficient. For the application of the model to Kazakhstan, the vegetation architecture variables were computed at the local (pixel) level based on extensive field surveys of the biophysical properties of vegetation in representative grassland areas of Kazakhstan. The comparison of both long-term data sets will be used to interpret their quality for scientific research in other disciplines. References:Propastin, P., Kappas, M. (2012). Retrieval of coarse-resolution leaf area index over the Republic of Kazakhstan using NOAA AVHRR satellite data and ground measurements," Remote Sensing, vol. 4, no. 1, pp. 220-246. Zaichun Zhu, Jian Bi, Yaozhong Pan, Sangram Ganguly, Alessandro Anav, Liang Xu, Arindam Samanta, Shilong Piao, Ramakrishna R. Nemani and Ranga B. Myneni (2013). Global Data Sets of Vegetation Leaf Area Index (LAI)3g and Fraction of photosynthetically Active Radiation (FPAR)3g Derived from Global Inventory Modeling and Mapping Studies (GIMMS) Normalized Difference Vegetation Index (NDVI3g) for the Period 1981 to 2011. Remote Sens. 2013, 5, 927-948; doi:10.3390/rs5020927

Plants and pixels: Comparing phenologies from the ground and from space (Invited)

NASA Astrophysics Data System (ADS)

Rutishauser, T.; Stoekli, R.; Jeanneret, F.; Peñuelas, J.

2010-12-01

Changes in the seasonality of life cycles of plants as recorded in phenological observations have been widely analysed at the species level with data available for many decades back in time. At the same time, seasonality changes in satellite-based observations and prognostic phenology models comprise information at the pixel-size or landscape scale. Change analysis of satellite-based records is restricted due to relatively short satellite records that further include gaps while model-based analyses are biased due to current model deficiencies. At 30 selected sites across Europe, we analysed three different sources of plant seasonality during the 1971-2000 period. Data consisted of (1) species-specific development stages of flowering and leave-out with different species observed at each site. (2) We used a synthetic phenological metric that integrates the common interannual phenological signal across all species at one site. (3) We estimated daily Leaf Area Index with a prognostic phenology model. The prior uncertainties of the model’s empirical parameter space are constrained by assimilating the Fraction of Photosynthetically Active Radiation absorbed by vegetation (FPAR) and Leaf Area Index (LAI) from the MODerate Resolution Imaging Spectroradiometer (MODIS). We extracted the day of year when the 25%, 50% and 75% thresholds were passed each spring. The question arises how the three phenological signals compare and correlate across climate zones in Europe. Is there a match between single species observations, species-based ground-observed metrics and the landscape-scale prognostic model? Are there single key-species across Europe that best represent a landscape scale measure from the prognostic model? Can one source substitute another and serve as proxy-data? What can we learn from potential mismatches? Focusing on changes in spring this contribution presents first results of an ongoing comparison study from a number of European test sites that will be extended to the pan-European phenological database Cost725 and PEP725.

Match and mismatch - comparing plant phenological metrics from ground-observations and from a prognostic model

NASA Astrophysics Data System (ADS)

Rutishauser, This; Stöckli, Reto; Jeanneret, François; Peñuelas, Josep

2010-05-01

Changes in the seasonality of life cycles of plants as recorded in phenological observations have been widely analysed at the species level with data available for many decades back in time. At the same time, seasonality changes in satellite-based observations and prognostic phenology models comprise information at the pixel-size or landscape scale. Change analysis of satellite-based records is restricted due to relatively short satellite records that further include gaps while model-based analyses are biased due to current model deficiencies., At 30 selected sites across Europe, we analysed three different sources of plant seasonality during the 1971-2000 period. Data consisted of (1) species-specific development stages of flowering and leave-out with different species observed at each site. (2) We used a synthetic phenological metric that integrates the common interannual phenological signal across all species at one site. (3) We estimated daily Leaf Area Index with a prognostic phenology model. The prior uncertainties of the model's empirical parameter space are constrained by assimilating the Fraction of Photosynthetically Active Radiation absorbed by vegetation (FPAR) and Leaf Area Index (LAI) from the MODerate Resolution Imaging Spectroradiometer (MODIS). We extracted the day of year when the 25%, 50% and 75% thresholds were passed each spring. The question arises how the three phenological signals compare and correlate across climate zones in Europe. Is there a match between single species observations, species-based ground-observed metrics and the landscape-scale prognostic model? Are there single key-species across Europe that best represent a landscape scale measure from the prognostic model? Can one source substitute another and serve as proxy-data? What can we learn from potential mismatches? Focusing on changes in spring this contribution presents first results of an ongoing comparison study from a number of European test sites that will be extended to the pan-European phenological database Cost725 and PEP725.

Grassland Production Change Due Comparison of NPP Estimates by Theoretical Model and Satellite Data from MODIS

NASA Astrophysics Data System (ADS)

Campbell, E. E.; Oliveira, J. D. C.; Lamparelli, R.; Soares, J.; Monteiro, L. A.; Jaiswal, D.; Sheehan, J. J.; Figueiredo, G. K. D. A.; Lynd, L. R.

2017-12-01

Accessing the changes in net primary production (NPP) from grassland in the globe has important applications, e.g. can identify where land have been degraded or in opposite site have been intensified. The aim of this study is to identify the changes occurred in grassland production due management practices and climate change. A recent comparison between a theoretical model of aboveground NPP and satellite data will be performed for the years 2000 to 2003. The theoretical model links NPP to climate, defined as total annual rainfall. Satellite data will use the total annual NPP from MODIS sensor (MOD17A3), that each pixel (spatial resolution of 1 km) include biome type information, daily meteorological data and the fraction absorbed of photosynthetic active radiation (FPAR) and leaf area index (LAI). Both NPP results were set in pastureland that is occupied by ruminants based on year 2000. The correlation between total NPP's values on year 2000 was 0.77. Therefore, the change in the differences between these models can reflect management practices and climate change impacts on grassland biomass production and also the reasonability of using both databases for predicting yield gap. The different from both NPP estimates will be then classified in three groups: no significant difference, significant increase and significant decrease. The outcome results will show the fluctuations in biomass from grassland worldwide. The regions with ongoing pasture degradation will be indentified, and can suggest a need for improvement. In the other hand, pastureland with significant increase in biomass will offer an example of intensification potential. The tendency of the pastureland in each region can give a support for policy makers in order to achieve a sustainability use of the land. Financial Support: FAPESP process 2017/06037-4, 2016/08741-8, 2017/08970-0, 2016/08742-4 and 2014/26767-9

Generating a Long-Term Land Data Record from the AVHRR and MODIS Instruments

NASA Technical Reports Server (NTRS)

Pedelty, Jeffrey; Devadiga, Sadashiva; Masuoka, Edward; Brown, Molly; Pinzon, Jorge; Tucker, Compton; Vermote, Eric; Prince, Stephen; Nagol, Jyotheshwar; Justice, Christopher;

Remote Sensing of Cloud, Aerosol, and Water Vapor Properties from MODIS

NASA Technical Reports Server (NTRS)

King, Michael D.

2001-01-01

MODIS is an earth-viewing cross-track scanning spectroradiometer launched on the Terra satellite in December 1999. MODIS scans a swath width sufficient to provide nearly complete global coverage every two days from a polar-orbiting, sun-synchronous, platform at an altitude of 705 km, and provides images in 36 spectral bands from 0.415 to 14.235 microns with spatial resolutions of 250 m (2 bands), 500 m (5 bands) and 1000 m (29 bands). These bands have been carefully selected to enable advanced studies of land, ocean, and atmospheric processes. In this presentation I will review the comprehensive set of remote sensing algorithms that have been developed for the remote sensing of atmospheric properties using MODIS data, placing primary emphasis on the principal atmospheric applications of: (1) developing a cloud mask for distinguishing clear sky from clouds, (2) retrieving global cloud radiative and microphysical properties, including cloud top pressure and temperature, effective emissivity, cloud optical thickness, thermodynamic phase, and effective radius, (3) monitoring tropospheric aerosol optical thickness over the land and ocean and aerosol size distribution over the ocean, (4) determining atmospheric profiles of moisture and temperature, and (5) estimating column water amount. The physical principles behind the determination of each of these atmospheric products will be described, together with an example of their application using MODIS observations. All products are archived into two categories: pixel-level retrievals (referred to as Level-2 products) and global gridded products at a latitude and longitude resolution of 1 deg (Level-3 products). An overview of the MODIS atmosphere algorithms and products, status, validation activities, and early level-2 and -3 results will be presented. Finally, I will present some highlights from the land and ocean algorithms developed for processing global MODIS observations, including: (1) surface reflectance, (2) vegetation indices, leaf area index, and FPAR, (3) albedo and nadir BRDF-adjusted reflectance, (4) normalized water-leaving radiance, (5) chlorophyll-a concentration, and (6) sea surface temperature.

Photon Recollision Probability: a Useful Concept for Cross Scale Consistency Check between Leaf Area Index and Foliage Clumping Products

NASA Astrophysics Data System (ADS)

Pisek, J.

2017-12-01

Clumping index (CI) is the measure of foliage aggregation relative to a random distribution of leaves in space. CI is an important factor for the correct quantification of true leaf area index (LAI). Global and regional scale CI maps have been generated from various multi-angle sensors based on an empirical relationship with the normalized difference between hotspot and darkspot (NDHD) index (Chen et al., 2005). Ryu et al. (2011) suggested that accurate calculation of radiative transfer in a canopy, important for controlling gross primary productivity (GPP) and evapotranspiration (ET) (Baldocchi and Harley, 1995), should be possible by integrating CI with incoming solar irradiance and LAI from MODIS land and atmosphere products. It should be noted that MODIS LAI/FPAR product uses internal non-empirical, stochastic equations for parameterization of foliage clumping. This raises a question if integration of the MODIS LAI product with empirically-based CI maps does not introduce any inconsistencies. Here, the consistency is examined independently through the `recollision probability theory' or `p-theory' (Knyazikhin et al., 1998) along with raw LAI-2000/2200 Plant Canopy Analyzer (PCA) data from > 30 sites, surveyed across a range of vegetation types. The theory predicts that the amount of radiation scattered by a canopy should depend only on the wavelength and the spectrally invariant canopy structural parameter p. The parameter p is linked to the foliage clumping (Stenberg et al., 2016). Results indicate that integration of the MODIS LAI product with empirically-based CI maps is feasible. Importantly, for the first time it is shown that it is possible to obtain p values for any location solely from Earth Observation data. This is very relevant for future applications of photon recollision probability concept for global and local monitoring of vegetation using Earth Observation data.

BOREAS Level-3b Landsat TM Imagery: At-sensor Radiances in BSQ Format

NASA Technical Reports Server (NTRS)

Hall, Forrest G. (Editor); Nickeson, Jaime; Knapp, David; Newcomer, Jeffrey A.; Cihlar, Josef

2000-01-01

For BOREAS, the level-3b Landsat TM data, along with the other remotely sensed images, were collected in order to provide spatially extensive information over the primary study areas. This information includes radiant energy, detailed land cover, and biophysical parameter maps such as FPAR and LAI. Although very similar in content to the level-3a Landsat TM products, the level-3b images were created to provide users with a directly usable at-sensor radiance image. Geographically, the level-3b images cover the BOREAS NSA and SSA. Temporally, the images cover the period of 22-Jun-1984 to 09-Jul-1996. The images are available in binary, image format files.

Intercomparisons of Prognostic, Diagnostic, and Inversion Modeling Approaches for Estimation of Net Ecosystem Exchange over the Pacific Northwest Region

NASA Astrophysics Data System (ADS)

Turner, D. P.; Jacobson, A. R.; Nemani, R. R.

2013-12-01

The recent development of large spatially-explicit datasets for multiple variables relevant to monitoring terrestrial carbon flux offers the opportunity to estimate the terrestrial land flux using several alternative, potentially complimentary, approaches. Here we developed and compared regional estimates of net ecosystem exchange (NEE) over the Pacific Northwest region of the U.S. using three approaches. In the prognostic modeling approach, the process-based Biome-BGC model was driven by distributed meteorological station data and was informed by Landsat-based coverages of forest stand age and disturbance regime. In the diagnostic modeling approach, the quasi-mechanistic CFLUX model estimated net ecosystem production (NEP) by upscaling eddy covariance flux tower observations. The model was driven by distributed climate data and MODIS FPAR (the fraction of incident PAR that is absorbed by the vegetation canopy). It was informed by coarse resolution (1 km) data about forest stand age. In both the prognostic and diagnostic modeling approaches, emissions estimates for biomass burning, harvested products, and river/stream evasion were added to model-based NEP to get NEE. The inversion model (CarbonTracker) relied on observations of atmospheric CO2 concentration to optimize prior surface carbon flux estimates. The Pacific Northwest is heterogeneous with respect to land cover and forest management, and repeated surveys of forest inventory plots support the presence of a strong regional carbon sink. The diagnostic model suggested a stronger carbon sink than the prognostic model, and a much larger sink that the inversion model. The introduction of Landsat data on disturbance history served to reduce uncertainty with respect to regional NEE in the diagnostic and prognostic modeling approaches. The FPAR data was particularly helpful in capturing the seasonality of the carbon flux using the diagnostic modeling approach. The inversion approach took advantage of a global network of CO2 observation stations, but had difficulty resolving regional fluxes such as that in the PNW given the still sparse nature of the CO2 measurement network.

Recent trends in Inner Asian forest dynamics to temperature and precipitation indicate high sensitivity to climate change

NASA Astrophysics Data System (ADS)

Poulter, B.; Pederson, N.; Liu, H.; Zhu, Z.; D'Arrigo, R.; Ciais, P.; Davi, N.; Frank, D. C.; Leland, C.; Myneni, R.; Piao, S.; Wang, T.

2012-12-01

Semi-arid ecosystems play an important role in regulating global climate and their response to climate change will depend on interactions between temperature, precipitation, and CO2. However, in cool-arid environments, precipitation is not the only limitation to forest productivity. For example, interactions between changes in precipitation and air temperature may enhance soil moisture stress while simultaneously extending growing season length, with unclear consequences for net carbon uptake. This presentation evaluates recent trends in productivity and seasonality of forests located in Inner Asia (Mongolia and Northern China) using satellite remote sensing, dendrochronology, and dynamic global vegetation model (DGVM) simulations to quantify the sensitivity of forest dynamics to decadal climate variability and trends. Long-term trends from satellite observations of FPAR between 1982-2010 show a greening of 21% of the region in spring (March, April May), but with 10% of the area 'browning' during summertime (June, July, August), the results of which are corroborated by trends in NPP simulated by the LPJ DGVM. Spring greening trends in FPAR are mainly explained by long-term trends in precipitation whereas summer browning trends are correlated with decreasing precipitation. Tree ring data from 25 sites confirm annual growth increments are mainly limited by summer precipitation (June, July, August) in Mongolia, and spring precipitation in northern China (March, April, May), with relatively weak prior-year lag effects. An ensemble of climate projections from the IPCC CMIP3 models indicates that warming temperatures (spring, summer) are expected to be associated with higher summer precipitation, which combined with CO2 causes large increases in NPP and eventual increase in forest cover in the Mongolian steppe. In the absence of a strong direct CO2 fertilization effect on plant growth (e.g., due to nutrient limitation), water stress or decreased carbon gain from higher autotrophic respiration results in decreased productivity and loss of forest cover.

Canopy structural complexity predicts forest canopy light absorption at continental scales

NASA Astrophysics Data System (ADS)

Atkins, J. W.; Fahey, R. T.; Hardiman, B. S.; Gough, C. M.

2017-12-01

Understanding how the physical structure of forest canopies influence light acquisition is a long-standing area of inquiry fundamental to advancing understanding of many areas of the physical sciences, including the modeling and interpretation of biogeochemical cycles. Conventional measures of forest canopy structure employed in earth system models are often limited to leaf area index (LAI)—a measure of the quantity of leaves in the canopy. However, more novel multi-dimensional measures of canopy structural complexity (CSC) that describe the arrangement of vegetation are now possible because of technological advances, and may improve modeled estimates of canopy light absorption. During 2016 and 2017, we surveyed forests at sites from across the eastern, southern, and midwestern United States using portable canopy LiDAR (PCL). This survey included 14 National Ecological Observation Network (NEON), Long-Term Ecological Research Network (LTER,) Ameriflux, and University affiliated sites. Our findings show that a composite model including CSC parameters and LAI explains 96.8% of the variance in light acquisition, measured as the fraction of photosynthetically absorbed radiation (fPAR) at the continental scale, and improvement of 12% over an LAI only model. Under high light sky conditions, measures of CSC are more strongly coupled with light acquisition than under low light, possibly because light scattering partially decouples CSC from canopy light absorption under low, predominately diffuse light conditions. We conclude that scalable estimates of CSC metrics may improve continent-wide estimates of canopy light absorption and, therefore, carbon uptake, with implications for remote sensing and earth system modeling.

Selective Cutting Impact on Carbon Storage in Fremont-Winema National Forest, Oregon

NASA Astrophysics Data System (ADS)

Huybrechts, C.; Cleve, C. T.

2004-12-01

Management personnel of the Fremont-Winema National Forest in southern Oregon were interested in investigating how selective cutting or fuel load reduction treatments affect forest carbon sinks and as an ancillary product, fire risk. This study was constructed with the objective of providing this information to the forest administrators, as well as to satisfy a directive to study carbon management, a component of the 2004 NASA's Application Division Program Plan. During the summer of 2004, a request for decision support tools by the forest management was addressed by a NASA sponsored student-led, student-run internship group called DEVELOP. This full-time10-week program was designed to be an introduction to work done by earth scientists, professional business / client relationships and the facilities available at NASA Ames. Four college and graduate students from varying educational backgrounds designed the study and implementation plan. The team collected data for five consecutive days in Oregon throughout the Fremont-Winema forest and the surrounding terrain, consisting of soil sampling for underground carbon dynamics, fire model and vegetation map validation. The goal of the carbon management component of the project was to model current carbon levels, then to gauge the effect of fuel load reduction treatments. To study carbon dynamics, MODIS derived fraction photosynthetically active radiation (FPAR) maps, regional climate data, and Landsat 5 generated dominant vegetation species and land cover maps were used in conjunction with the NASA - Carnegie-Ames-Stanford-Approach (CASA) model. To address fire risk the dominant vegetation species map was used to estimate fuel load based on species biomass in conjunction with a mosaic of digital elevation models (DEMs) as components to the creation of an Anderson-inspired fuel map, a rate of spread in meters/minute map and a flame length map using ArcMap 9 and FlamMap. Fire risk results are to be viewed qualitatively as maps output spatial distribution of data rather then quantitative assessment of risk. For the first time ever, the resource managers at the Fremont-Winema forest will be taking into consideration the value of carbon as a resource in their decision making process for the 2005 Fremont-Winema forest management plan.

Estimating primary productivity of tropical oil palm in Malaysia using remote sensing technique and ancillary data

NASA Astrophysics Data System (ADS)

Kanniah, K. D.; Tan, K. P.; Cracknell, A. P.

2014-10-01

The amount of carbon sequestration by vegetation can be estimated using vegetation productivity. At present, there is a knowledge gap in oil palm net primary productivity (NPP) at a regional scale. Therefore, in this study NPP of oil palm trees in Peninsular Malaysia was estimated using remote sensing based light use efficiency (LUE) model with inputs from local meteorological data, upscaled leaf area index/fractional photosynthetically active radiation (LAI/fPAR) derived using UK-DMC 2 satellite data and a constant maximum LUE value from the literature. NPP values estimated from the model was then compared and validated with NPP estimated using allometric equations developed by Corley and Tinker (2003), Henson (2003) and Syahrinudin (2005) with diameter at breast height, age and the height of the oil palm trees collected from three estates in Peninsular Malaysia. Results of this study show that oil palm NPP derived using a light use efficiency model increases with respect to the age of oil palm trees, and it stabilises after ten years old. The mean value of oil palm NPP at 118 plots as derived using the LUE model is 968.72 g C m-2 year-1 and this is 188% - 273% higher than the NPP derived from the allometric equations. The estimated oil palm NPP of young oil palm trees is lower compared to mature oil palm trees (<10 years old), as young oil palm trees contribute to lower oil palm LAI and therefore fPAR, which is an important variable in the LUE model. In contrast, it is noted that oil palm NPP decreases with respect to the age of oil palm trees as estimated using the allomeric equations. It was found in this study that LUE models could not capture NPP variation of oil palm trees if LAI/fPAR is used. On the other hand, tree height and DBH are found to be important variables that can capture changes in oil palm NPP as a function of age.

Modeling the health and productivity of Oak Savannas in central USA

NASA Astrophysics Data System (ADS)

Nightingale, J. M.; Hill, M. J.

2012-12-01

Oak species have a long history of domination in eastern North America and their present distribution in various regions exceeds that recorded in the original forests at the time of European settlement. The increase in oak during the late 18th and 19th centuries can be attributed to historical changes in disturbance regimes in the eastern biome. The expansion in oak distribution has occurred on xeric or nutrient-poor sites, which indicates the stress tolerance capabilities of many oak species. The aim of this research is to assess the health and productivity of the fragmented oak savannas that span from Texas north to the Canada border using statewide GAP, climate and MODIS data and the 3PGS (Physiological Principles Predicting Growth using satellite data) ecosystem process model. 3-PGS is a simple big-leaf productivity model that sets upper limits on monthly gross primary productivity (GPP) by determining the amount of photosynthetically active radiation absorbed (APAR) by vegetation and the photosynthetic capacity (LUE) of the canopy. The utilized portion of APAR is calculated by reducing total PAR by an amount determined by the most constraining of a series of environmental modifiers that affect gas exchange through stomata. These include: (a) high daytime atmospheric VPD; (b) soil water availability; and (c) the frequency of sub-freezing temperatures (<-2 °C). Climate data including day length, precipitation, average temperature and vapor pressure deficit are obtained from the Daymet daily gridded surface data from Oak Ridge National Laboratory (ORNL). The fraction of APAR is obtained from the MODIS terra/aqua combined product. Monthly surfaces were derived for the study period 2003-2008 spanning available MODIS and Climate datasets. Soil properties for the entire U.S.A., derived from luster analysis of STATSGO soil parameters, terrain and climate observations were obtained from ORNL. Oak savannas within this region are identified using the statewide Gap Analysis Program data provided by USGS. Several landsat scenes selected across the study region provided an estimate of the seasonal variation in fPAR and distinction between the tree and understory grass signals.

Temporal dynamics of spectral bioindicators evidence biological and ecological differences among functional types in a cork oak open woodland

NASA Astrophysics Data System (ADS)

Cerasoli, Sofia; Costa e Silva, Filipe; Silva, João M. N.

2016-06-01

The application of spectral vegetation indices for the purpose of vegetation monitoring and modeling increased largely in recent years. Nonetheless, the interpretation of biophysical properties of vegetation through their spectral signature is still a challenging task. This is particularly true in Mediterranean oak forest characterized by a high spatial and temporal heterogeneity. In this study, the temporal dynamics of vegetation indices expected to be related with green biomass and photosynthetic efficiency were compared for the canopy of trees, the herbaceous layer, and two shrub species: cistus ( Cistus salviifolius) and ulex ( Ulex airensis). coexisting in a cork oak woodland. All indices were calculated from in situ measurements with a FieldSpec3 spectroradiometer (ASD Inc., Boulder, USA). Large differences emerged in the temporal trends and in the correlation between climate and vegetation indices. The relationship between spectral indices and temperature, radiation, and vapor pressure deficit for cork oak was opposite to that observed for the herbaceous layer and cistus. No correlation was observed between rainfall and vegetation indices in cork oak and ulex, but in the herbaceous layer and in the cistus, significant correlations were found. The analysis of spectral vegetation indices with fraction of absorbed PAR (fPAR) and quantum yield of chlorophyll fluorescence ( ΔF/ Fm') evidenced strongest relationships with the indices Normalized Difference Water Index (NDWI) and Photochemical Reflectance Index (PRI)512, respectively. Our results, while confirms the ability of spectral vegetation indices to represent temporal dynamics of biophysical properties of vegetation, evidence the importance to consider ecosystem composition for a correct ecological interpretation of results when the spatial resolution of observations includes different plant functional types.

Temporal dynamics of spectral bioindicators evidence biological and ecological differences among functional types in a cork oak open woodland.

PubMed

Cerasoli, Sofia; Costa E Silva, Filipe; Silva, João M N

2016-06-01

The application of spectral vegetation indices for the purpose of vegetation monitoring and modeling increased largely in recent years. Nonetheless, the interpretation of biophysical properties of vegetation through their spectral signature is still a challenging task. This is particularly true in Mediterranean oak forest characterized by a high spatial and temporal heterogeneity. In this study, the temporal dynamics of vegetation indices expected to be related with green biomass and photosynthetic efficiency were compared for the canopy of trees, the herbaceous layer, and two shrub species: cistus (Cistus salviifolius) and ulex (Ulex airensis). coexisting in a cork oak woodland. All indices were calculated from in situ measurements with a FieldSpec3 spectroradiometer (ASD Inc., Boulder, USA). Large differences emerged in the temporal trends and in the correlation between climate and vegetation indices. The relationship between spectral indices and temperature, radiation, and vapor pressure deficit for cork oak was opposite to that observed for the herbaceous layer and cistus. No correlation was observed between rainfall and vegetation indices in cork oak and ulex, but in the herbaceous layer and in the cistus, significant correlations were found. The analysis of spectral vegetation indices with fraction of absorbed PAR (fPAR) and quantum yield of chlorophyll fluorescence (ΔF/Fm') evidenced strongest relationships with the indices Normalized Difference Water Index (NDWI) and Photochemical Reflectance Index (PRI)512, respectively. Our results, while confirms the ability of spectral vegetation indices to represent temporal dynamics of biophysical properties of vegetation, evidence the importance to consider ecosystem composition for a correct ecological interpretation of results when the spatial resolution of observations includes different plant functional types.

Retrieval of the Land Surface Reflectance for Landsat-8 and Sentinel-2 and its validation.

NASA Astrophysics Data System (ADS)

Roger, J. C.; Vermote, E.; Skakun, S.; Franch, B.; Holben, B. N.; Justice, C. O.

2017-12-01

The land surface reflectance is a fundamental climate data record at the basis of the derivation of other climate data records (Albedo, LAI/Fpar, Vegetation indices) and a key parameter in the understanding of the land-surface-climate processes. For 25 years, Vermote and al. develop atmospheric corrections methods to define a land surface reflectance product for various satellites (AVHRR, MODIS, VIIRS…). This presentation highlights the algorithms developed both for Landsant-8 and Sentinel-2. We also emphasize the validation of the "Land surface reflectance" satellite products, which is a very important step to be done. For that purpose, we compared the surface reflectance products to a reference determined by using the accurate radiative transfer code 6S and very detailed measurements of the atmosphere obtained over the AERONET network (which allows to test for a large range of aerosol characteristics); formers being important inputs for atmospheric corrections. However, the application of this method necessitates the definition of a very detailed protocol for the use of AERONET data especially as far as size distribution and absorption are concerned, so that alternative validation methods or protocols could be compared. We describe here the protocol we have been working on based on our experience with the AERONET data and its application to Landsat-8 and Sentinel-2). We also derive a detailed error budget in relation to this approach. For a mean loaded atmosphere, t550 less than 0.25, the maximum uncertainty is 0.0025 corresponding to a relative uncertainty (in the RED channels): U < 1% for rsurf > 0.10, and 1% < U <2% for 0.10 >rsurf > 0.04.

Progress towards the use of publicly available data networks to conduct cross-scale historical reconstructions of carbon dynamics in US Drylands

NASA Astrophysics Data System (ADS)

Washington-Allen, R. A.; Landolt, K.; Emanuel, R. E.; Therrell, M. D.; Nagle, N.; Grissino-Mayer, H. D.; Poulter, B.

2016-12-01

Emergent scale properties of water-limited or Dryland ecosystem's carbon flux are unknown at spatial scales from local to global and time scales of 10 - 1000 years or greater. The width of a tree ring is a metric of production that has been correlated with the amount of precipitation. This relationship has been used to reconstruct rainfall and fire histories in the Drylands of the southwestern US. The normalized difference vegetation index (NDVI) is globally measured by selected satellite sensors and is highly correlated with the fraction of solar radiation which is absorbed for photosynthesis by plants (FPAR), as well as with vegetation biomass, net primary productivity (NPP), and tree ring width. Publicly available web-based archives of free NDVI and tree ring data exist and have allowed historical temporal reconstructions of carbon dynamics for the past 300 to 500 years. Climate and tree ring databases have been used to spatially reconstruct drought dynamics for the last 500 years in the western US. In 2007, we hypothesized that NDVI and tree ring width could be used to spatially reconstruct carbon dynamics in US Drylands. In 2015, we succeeded with a 300-year historical spatial reconstruction of NPP in California using a Blue Oak tree ring chronology. Online eddy covariance flux tower measures of NPP are well correlated with satellite measures of NPP. This suggests that net ecosystem exchange (NEE = NPP - soil Respiration) could be historically reconstructed across Drylands. Ongoing research includes 1) scaling historical spatial reconstruction to US Drylands, 2) comparing the use of single versus multiple tree ring species (r2 = 68) and 3) use of the eddy flux tower network, remote sensing, and tree ring data to historically spatially reconstruct Dryland NEE.

The affordable care act and family planning services: the effect of optional medicaid expansion on safety net programs.

PubMed

Lanese, Bethany G; Oglesby, Willie H

2016-01-01

Title X of the Public Health Service Act provides funding for a range of reproductive health services, with a priority given to low-income persons. Now that many of these services are provided to larger numbers of people with low-income since the passage of the Affordable Care Act and Medicaid expansion, questions remain on the continued need for the Title X program. The current project highlights the importance of these safety net programs. To help inform this policy issue, research was conducted to examine the revenue and service changes for Title X per state and compare those findings to the states' Medicaid expansion and demographics. The dataset include publicly available data from 2013 and 2014 Family Planning Annual Reports (FPAR). Paired samples differences of means t-tests were then used to compare the means of family planning participation rates for 2013 and 2014 across the different categories for Medicaid expansion states and non-expansion states. The ACA has had an impact on Title X services, but the link is not as direct as previously thought. The findings indicate that all states' Title X funded clinics lost revenue; however, expansion states fared better than non-expansion states. While the general statements from the FPAR National surveys certainly are supported in that Title X providers have decreased in number and scope of services, which has led to the decrease in total clients, these variations are not evenly applied across the states. The ACA has very likely had an impact on Title X services, but the link is not as obvious as previously thought. Title X funded clinics have helped increase access to health insurance at a greater rate in expansion states than non-expansion states. There was much concern from advocates that with the projected increased revenue from Medicaid and private insurance, that Title X programs could be deemed unnecessary. However, this revenue increase has yet to actually pan out. Title X still helps fill a much needed service gap for a vulnerable population.

Estimating cropland NPP using national crop inventory and MODIS derived crop specific parameters

NASA Astrophysics Data System (ADS)

Bandaru, V.; West, T. O.; Ricciuto, D. M.

2011-12-01

Estimates of cropland net primary production (NPP) are needed as input for estimates of carbon flux and carbon stock changes. Cropland NPP is currently estimated using terrestrial ecosystem models, satellite remote sensing, or inventory data. All three of these methods have benefits and problems. Terrestrial ecosystem models are often better suited for prognostic estimates rather than diagnostic estimates. Satellite-based NPP estimates often underestimate productivity on intensely managed croplands and are also limited to a few broad crop categories. Inventory-based estimates are consistent with nationally collected data on crop yields, but they lack sub-county spatial resolution. Integrating these methods will allow for spatial resolution consistent with current land cover and land use, while also maintaining total biomass quantities recorded in national inventory data. The main objective of this study was to improve cropland NPP estimates by using a modification of the CASA NPP model with individual crop biophysical parameters partly derived from inventory data and MODIS 8day 250m EVI product. The study was conducted for corn and soybean crops in Iowa and Illinois for years 2006 and 2007. We used EVI as a linear function for fPAR, and used crop land cover data (56m spatial resolution) to extract individual crop EVI pixels. First, we separated mixed pixels of both corn and soybean that occur when MODIS 250m pixel contains more than one crop. Second, we substituted mixed EVI pixels with nearest pure pixel values of the same crop within 1km radius. To get more accurate photosynthetic active radiation (PAR), we applied the Mountain Climate Simulator (MTCLIM) algorithm with the use of temperature and precipitation data from the North American Land Data Assimilation System (NLDAS-2) to generate shortwave radiation data. Finally, county specific light use efficiency (LUE) values of each crop for years 2006 to 2007 were determined by application of mean county inventory NPP and EVI-derived APAR into the Monteith equation. Results indicate spatial variability in LUE values across Iowa and Illinois. Northern regions of both Iowa and Illinois have higher LUE values than southern regions. This trend is reflected in NPP estimates. Results also show that corn has higher LUE values than soybean, resulting in higher NPP for corn than for soybean. Current NPP estimates were compared with NPP estimates from MOD17A3 product and with county inventory-based NPP estimates. Results indicate that current NPP estimates closely agree with inventory-based estimates, and that current NPP estimates are higher than those of the MOD17A3 product. It was also found that when mixed pixels were substituted with nearest pure pixels, revised NPP estimates were improved showing better agreement with inventory-based estimates.

Estimation of Mangrove Net Primary Production and Carbon Sequestration service using Light Use Efficiency model in the Sunderban Biosphere region, India

NASA Astrophysics Data System (ADS)

Sannigrahi, Srikanta; Sen, Somnath; Paul, Saikat

2016-04-01

Net Primary Production (NPP) of mangrove ecosystem and its capacity to sequester carbon from the atmosphere may be used to quantify the regulatory ecosystem services. Three major group of parameters has been set up as BioClimatic Parameters (BCP): (Photosynthetically Active Radiation (PAR), Absorbed PAR (APAR), Fraction of PAR (FPAR), Photochemical Reflectance Index (PRI), Light Use Efficiency (LUE)), BioPhysical Parameters (BPP) :(Normalize Difference Vegetation Index (NDVI), scaled NDVI, Enhanced Vegetation Index (EVI), scaled EVI, Optimised and Modified Soil Adjusted Vegetation Index (OSAVI, MSAVI), Leaf Area Index (LAI)), and Environmental Limiting Parameters (ELP) (Temperature Stress (TS), Land Surface Water Index (LSWI), Normalize Soil Water Index (NSWI), Water Stress Scalar (WS), Inversed WS (iWS) Land Surface Temperature (LST), scaled LST, Vapor Pressure Deficit (VPD), scaled VPD, and Soil Water Deficit Index (SWDI)). Several LUE models namely Carnegie Ames Stanford Approach (CASA), Eddy Covariance - LUE (EC-LUE), Global Production Efficiency Model (GloPEM), Vegetation Photosynthesis Model (VPM), MOD NPP model, Temperature and Greenness Model (TG), Greenness and Radiation model (GR) and MOD17 was adopted in this study to assess the spatiotemporal nature of carbon fluxes. Above and Below Ground Biomass (AGB & BGB) was calculated using field based estimation of OSAVI and NDVI. Microclimatic zonation has been set up to assess the impact of coastal climate on environmental limiting factors. MODerate Resolution Imaging Spectroradiometer (MODIS) based yearly Gross Primary Production (GPP) and NPP product MOD17 was also tested with LUE based results with standard model validation statistics: Root Mean Square of Error (RMSE), Mean Absolute Error (MEA), Bias, Coefficient of Variation (CV) and Coefficient of Determination (R2). The performance of CASA NPP was tested with the ground based NPP with R2 = 0.89 RMSE = 3.28 P = 0.01. Among the all adopted models, EC-LUE and VPM models has explained the maximum variances (>80%) in comparison to the other model. Study result has also showed that the BPP has explained the maximum model variances (>93%) followed by BCP (>65%) and ELP (>50%). Scaled WS, iWS, LST, VPD, NDVI was performed better in a minimum ELP condition whereas surface moisture and wetness was highly correlated with the AGB and NPP (R2 = 0.86 RMSE = 1.83). During this study period (2000-2013), it was found that there was a significantly declining trend (R2 = 0.32 P = 0.05) of annual NPP and the maximum decrease was found in the eastern part where built-up area was mainly accounted for reduction of NPP. BCP are explained higher variances (>80%) in the optimum climatic condition exist along the coastal stretches in comparison to the landward extent (>45%).

Coupling gross primary production and transpiration for a consistent estimate of canopy water use efficiency

NASA Astrophysics Data System (ADS)

Yebra, Marta; van Dijk, Albert

2015-04-01

Water use efficiency (WUE, the amount of transpiration or evapotranspiration per unit gross (GPP) or net CO2 uptake) is key in all areas of plant production and forest management applications. Therefore, mutually consistent estimates of GPP and transpiration are needed to analysed WUE without introducing any artefacts that might arise by combining independently derived GPP and ET estimates. GPP and transpiration are physiologically linked at ecosystem level by the canopy conductance (Gc). Estimates of Gc can be obtained by scaling stomatal conductance (Kelliher et al. 1995) or inferred from ecosystem level measurements of gas exchange (Baldocchi et al., 2008). To derive large-scale or indeed global estimates of Gc, satellite remote sensing based methods are needed. In a previous study, we used water vapour flux estimates derived from eddy covariance flux tower measurements at 16 Fluxnet sites world-wide to develop a method to estimate Gc using MODIS reflectance observations (Yebra et al. 2013). We combined those estimates with the Penman-Monteith combination equation to derive transpiration (T). The resulting T estimates compared favourably with flux tower estimates (R2=0.82, RMSE=29.8 W m-2). Moreover, the method allowed a single parameterisation for all land cover types, which avoids artefacts resulting from land cover classification. In subsequent research (Yebra et al, in preparation) we used the same satellite-derived Gc values within a process-based but simple canopy GPP model to constrain GPP predictions. The developed model uses a 'big-leaf' description of the plant canopy to estimate the mean GPP flux as the lesser of a conductance-limited and radiation-limited GPP rate. The conductance-limited rate was derived assuming that transport of CO2 from the bulk air to the intercellular leaf space is limited by molecular diffusion through the stomata. The radiation-limited rate was estimated assuming that it is proportional to the absorbed photosynthetically active radiation (PAR), calculated as the product of the fraction of absorbed PAR (fPAR) and PAR flux. The proposed algorithm performs well when evaluated against flux tower GPP (R2=0.79, RMSE= 1.93 µmol m2 s-1). Here we use GPP and T estimates previously derived at the same 16 Fluxnet sites to analyse WUE. Satellite-derived WUE explained variation in (long-term average) WUE among plant functional types but evergreen needleleaf had higher WUE than predicted. The benefit of our approach is that it uses mutually consistent estimates of GPP and T to derive canopy-level WUE without any land cover classification artefacts. References Baldocchi, D. (2008). Turner Review No. 15: 'Breathing' of the terrestrial biosphere: lessons learned from a global network of carbon dioxide flux measurement systems. Australian Journal of Botany, 56, 26 Kelliher, F.M., Leuning, R., Raupach, M.R., & Schulze, E.D. (1995). Maximum conductances for evaporation from global vegetation types. Agricultural and Forest Meteorology, 73, 1-16 Yebra, M., Van Dijk, A., Leuning, R., Huete, A., & Guerschman, J.P. (2013). Evaluation of optical remote sensing to estimate actual evapotranspiration and canopy conductance. Remote Sensing of Environment, 129, 250-261

BOREAS Level-2 NS001 TMS Imagery: Reflectance and Temperature in BSQ Format

NASA Technical Reports Server (NTRS)

Lobitz, Brad; Spanner, Michael; Hall, Forrest G. (Editor); Newcomer, Jeffrey A. (Editor); Strub, Richard

2000-01-01

For BOREAS, the NS001 TMS images, along with the other remotely sensed data, were collected to provide spatially extensive information over the primary study areas. This information includes detailed land cover and biophysical parameter maps such as fPAR and LAI. Collection of the NS001 images occurred over the study areas during the 1994 field campaigns. The level-2 NS001 data are atmospherically corrected versions of some of the best original NS001 imagery and cover the dates of 19-Apr-1994, 07-Jun-1994, 21-Jul-1994, 08-Aug-1994, and 16-Sep-1994. The data are not geographically/geometrically corrected; however, files of relative X and Y coordinates for each image pixel were derived by using the C130 INS data in an NS001 scan model. The data are provided in binary image format files.

Estimating Vegetation Primary Production in the Heihe River Basin of China with Multi-Source and Multi-Scale Data.

PubMed

Cui, Tianxiang; Wang, Yujie; Sun, Rui; Qiao, Chen; Fan, Wenjie; Jiang, Guoqing; Hao, Lvyuan; Zhang, Lei

2016-01-01

Estimating gross primary production (GPP) and net primary production (NPP) are significant important in studying carbon cycles. Using models driven by multi-source and multi-scale data is a promising approach to estimate GPP and NPP at regional and global scales. With a focus on data that are openly accessible, this paper presents a GPP and NPP model driven by remotely sensed data and meteorological data with spatial resolutions varying from 30 m to 0.25 degree and temporal resolutions ranging from 3 hours to 1 month, by integrating remote sensing techniques and eco-physiological process theories. Our model is also designed as part of the Multi-source data Synergized Quantitative (MuSyQ) Remote Sensing Production System. In the presented MuSyQ-NPP algorithm, daily GPP for a 10-day period was calculated as a product of incident photosynthetically active radiation (PAR) and its fraction absorbed by vegetation (FPAR) using a light use efficiency (LUE) model. The autotrophic respiration (Ra) was determined using eco-physiological process theories and the daily NPP was obtained as the balance between GPP and Ra. To test its feasibility at regional scales, our model was performed in an arid and semi-arid region of Heihe River Basin, China to generate daily GPP and NPP during the growing season of 2012. The results indicated that both GPP and NPP exhibit clear spatial and temporal patterns in their distribution over Heihe River Basin during the growing season due to the temperature, water and solar influx conditions. After validated against ground-based measurements, MODIS GPP product (MOD17A2H) and results reported in recent literature, we found the MuSyQ-NPP algorithm could yield an RMSE of 2.973 gC m(-2) d(-1) and an R of 0.842 when compared with ground-based GPP while an RMSE of 8.010 gC m(-2) d(-1) and an R of 0.682 can be achieved for MODIS GPP, the estimated NPP values were also well within the range of previous literature, which proved the reliability of our modelling results. This research suggested that the utilization of multi-source data with various scales would help to the establishment of an appropriate model for calculating GPP and NPP at regional scales with relatively high spatial and temporal resolution.

Estimating Vegetation Primary Production in the Heihe River Basin of China with Multi-Source and Multi-Scale Data

PubMed Central

Cui, Tianxiang; Wang, Yujie; Sun, Rui; Qiao, Chen; Fan, Wenjie; Jiang, Guoqing; Hao, Lvyuan; Zhang, Lei

2016-01-01

Estimating gross primary production (GPP) and net primary production (NPP) are significant important in studying carbon cycles. Using models driven by multi-source and multi-scale data is a promising approach to estimate GPP and NPP at regional and global scales. With a focus on data that are openly accessible, this paper presents a GPP and NPP model driven by remotely sensed data and meteorological data with spatial resolutions varying from 30 m to 0.25 degree and temporal resolutions ranging from 3 hours to 1 month, by integrating remote sensing techniques and eco-physiological process theories. Our model is also designed as part of the Multi-source data Synergized Quantitative (MuSyQ) Remote Sensing Production System. In the presented MuSyQ-NPP algorithm, daily GPP for a 10-day period was calculated as a product of incident photosynthetically active radiation (PAR) and its fraction absorbed by vegetation (FPAR) using a light use efficiency (LUE) model. The autotrophic respiration (Ra) was determined using eco-physiological process theories and the daily NPP was obtained as the balance between GPP and Ra. To test its feasibility at regional scales, our model was performed in an arid and semi-arid region of Heihe River Basin, China to generate daily GPP and NPP during the growing season of 2012. The results indicated that both GPP and NPP exhibit clear spatial and temporal patterns in their distribution over Heihe River Basin during the growing season due to the temperature, water and solar influx conditions. After validated against ground-based measurements, MODIS GPP product (MOD17A2H) and results reported in recent literature, we found the MuSyQ-NPP algorithm could yield an RMSE of 2.973 gC m-2 d-1 and an R of 0.842 when compared with ground-based GPP while an RMSE of 8.010 gC m-2 d-1 and an R of 0.682 can be achieved for MODIS GPP, the estimated NPP values were also well within the range of previous literature, which proved the reliability of our modelling results. This research suggested that the utilization of multi-source data with various scales would help to the establishment of an appropriate model for calculating GPP and NPP at regional scales with relatively high spatial and temporal resolution. PMID:27088356

Strong Links Between Teleconnections and Ecosystem Exchange Found at a Pacific Northwest Old-Growth Forest from Flux Tower and MODIS EVI Data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wharton, S; Chasmer, L; Falk, M

2009-03-12

Variability in three Pacific teleconnection patterns are examined to see if net carbon exchange at a low-elevation, old-growth forest is affected by climatic changes associated with these periodicities. Examined are the Pacific Decadal Oscillation (PDO), Pacific/North American Oscillation (PNA) and El Nino-Southern Oscillation (ENSO). We use nine years of eddy covariance CO{sub 2}, H{sub 2}O and energy fluxes measured at the Wind River AmeriFlux site, Washington, USA and eight years of tower-pixel remote sensing data from the Moderate Resolution Imaging Spectroradiometer (MODIS) to address this question. We compute a new Composite Climate Index (CCI) based on the three Pacific Oscillationsmore » to divide the measurement period into positive- (2003 and 2005), negative- (1999 and 2000) and neutral-phase climate years (2001, 2002, 2004, 2006 and 2007). The forest transitioned from an annual net carbon sink (NEP = + 217 g C m{sup -2} year{sup -1}, 1999) to a source (NEP = - 100 g C m{sup -2} year{sup -1}, 2003) during two dominant teleconnection patterns. Net ecosystem productivity (NEP), water use efficiency (WUE) and light use efficiency (LUE) were significantly different (P < 0.01) during positive (NEP = -0.27 g C m{sup -2} day{sup -1}, WUE = 4.1 mg C/g H{sub 2}O, LUE = 0.94 g C MJ{sup -1}) and negative (NEP = +0.37 g C m{sup -2} day{sup -1}, WUE = 3.4 mg C/g H{sub 2}O, LUE = 0.83 g C MJ{sup -1}) climate phases. The CCI was linked to variability in the MODIS Enhanced Vegetation Index (EVI) but not to MODIS Fraction of absorbed Photosynthetically Active Radiation (FPAR). EVI was highest during negative climate phases (1999 and 2000) and was positively correlated with NEP and showed potential for using MODIS to estimate teleconnection-driven anomalies in ecosystem CO{sub 2} exchange in old-growth forests. This work suggests that any increase in the strength or frequency of ENSO coinciding with in-phase, low frequency Pacific oscillations (PDO and PNA) will likely increase CO{sub 2} uptake variability in Pacific Northwest conifer forests.« less

Sensitivity of MODIS evapotranspiration algorithm (MOD16) to the acuracy of meteorological data and land use and land cover parameterization

NASA Astrophysics Data System (ADS)

Ruhoff, Anderson; Santini Adamatti, Daniela

2017-04-01

MODIS evapotranspiration (MOD16) is currently available with 1 km of spatial resolution over 109.03 Million km2 of vegetated land surface areas and this information is widely used to evaluate the linkages between hydrological, energy and carbon cycles. The algorithm is driven by meteorological reanalysis data and MODIS remotely-sensed data, which include land use and land cover classification (MCD12Q1), leaf area index (LAI) and fraction of absorbed photosynthetically active radiation (FPAR) (MOD15A2) and albedo (MOD43b3). For calibration and parameterization, the algorithm uses a Biome Property Look-up Table (BPLUT) based on MCD12Q1 land cover classification. Several studies evaluated MOD16 accuracy using evapotranspiration measurements and water balance analysis, showing that this product can reproduce global evapotranspiration effectively under a variety climate condition, from local to wide-basin scale, with uncertainties up to 25%. In this study, we evaluated the sensitivity of MOD16 algorithm to land use and land cover parameterization and to meteorological data. Considering that MCD12Q1 has an accuracy between 70 and 85% at continental scale, we changed land cover parametererization to understand the influence of land use and land cover classification on MOD16 evapotranspiration estimations. Knowing that meteorological reanalysis data also have uncertainties (mostly related to the coarse spatial resolution), we compared MOD16 evapotranspiration driven by observed meteorological data to those driven by the reanalysis data. Our analysis were carried in South America, with evapotranspiration and meteorological measurements from the Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA) at 8 different sites, including tropical rainforest, tropical dry forest, selective logged forest, seasonal flooded forest and pasture/agriculture. Our results indicate that land use and land cover classification has a strong influence on MOD16 algorithm. The use of incorrect parametererization due to land use and land cover misclassification can introduce large erros in estimates of evapotranspiration. We also found that the biases in meteorological reanalysis data can introduce considerable errors into the estimations. Overall, there is a significant potential for mapping and monitoring global evapotranspiration using MODIS remotely-sensed images combined to meteorological reanalysis data.

Crosstalk between Fas and JNK determines lymphocyte apoptosis after ionizing radiation.

PubMed

Praveen, Koganti; Saxena, Nandita

2013-06-01

Radiation simultaneously activate Fas and JNK pathway in lymphocytes but their precise interaction is not clearly understood. Activation of Fas pathway is required for radiation induced apoptosis, however induction of JNK pathway may or may not contribute in apoptosis. Here we report that Fas, Fas associated death domain and total JNK are activated in a dose- and time-dependent radiation exposure. A biphasic pattern of phospho-JNK was found at lower doses (1 and 2 Gy), however at higher doses of radiation phospho-JNK was continuously activated. Interestingly, Fas ligand expression remained biphasic at all the doses of radiation. Our results suggest that the Fas pathway is the major player in radiation-induced apoptosis, with JNK playing a contributory role. We also observed that Fas ligand expression by radiation is dependent on JNK activation. We also propose that radiation activates JNK pathway, but sustained activation is required for maximal induction of apoptosis at later times. Our findings define a mechanism for crosstalk between JNK and Fas pathway in radiation-induced apoptosis, which may lead to the development of new therapeutic strategies.

A long-term simulation of forest carbon fluxes over the Qilian Mountains

NASA Astrophysics Data System (ADS)

Yan, Min; Tian, Xin; Li, Zengyuan; Chen, Erxue; Li, Chunmei; Fan, Wenwu

2016-10-01

In this work, we integrated a remote-sensing-based (the MODIS MOD_17 Gross Primary Productivity (GPP) model (MOD_17)) and a process-based (the Biome-BioGeochemical Cycles (Biome-BGC) model) ecological model in order to estimate long-term (from 2000 to 2012) forest carbon fluxes over the Qilian Mountains in northwest China, a cold and arid forest ecosystem. Our goal was to obtain an accurate and quantitative simulation of spatial GPP patterns using the MOD_17 model and a temporal description of forest processes using the Biome-BGC model. The original MOD_17 model was first optimized using a biome-specific parameter, observed meteorological data, and reproduced fPAR at the eddy covariance site. The optimized MOD_17 model performed much better (R2 = 0.91, RMSE = 5.19 gC/m2/8d) than the original model (R2 = 0.47, RMSE = 20.27 gC/m2/8d). The Biome-BGC model was then calibrated using GPP for 30 representative forest plots selected from the optimized MOD_17 model. The calibrated Biome-BGC model was then driven in order to estimate forest GPP, net primary productivity (NPP), and net ecosystem exchange (NEE). GPP and NEE were validated against two-year (2010 and 2011) EC measurements (R2 = 0.79, RMSE = 1.15 gC/m2/d for GPP; and R2 = 0.69, RMSE = 1.087 gC/m2/d for NEE). NPP estimates from 2000 to 2012 were then compared to dendrochronological measurements (R2 = 0.73, RMSE = 24.46 gC/m2/yr). Our results indicated that integration of the two models can be used for estimating carbon fluxes with good accuracy and a high temporal and spatial resolution. Overall, NPP displayed a downward trend, with an average rate of 0.39 gC/m2/yr, from 2000 and 2012 over the Qilian Mountains. Simulated average annual NPP yielded higher values for the southeast as compared to the northwest. The most positive correlative climatic factor to average annual NPP was downward shortwave radiation. The vapor pressure deficit, and mean temperature and precipitation yielded negative correlations to average annual NPP.

Uncertainties in estimates of fAPAR for photosynthesis (fAPARPSN) in tropical, Arctic/boreal, coastal, and wetland-dominant regions when approximated with fAPARcanopy and NDVI

NASA Astrophysics Data System (ADS)

Zhang, Q.; Yao, T.

2016-12-01

The climate is affected by the land surface through regulating the exchange of mass and energy with the atmosphere. The energy that reaches the land surface has three pathways: (1) reflected into atmosphere; (2) absorbed for photosynthesis; and (3) discarded as latent and sensible heat or emitted as fluorescence. Vegetation removes CO2 from the atmosphere during the process of photosynthesis, but also releases CO2 back into the atmosphere through the process of respiration. The complex set of vegetation-soil-atmosphere interactions requires that a realistic land-surface parameterization be included in any climate model or general circulation model (GCM) to accurately simulate canopy photosynthesis and stomatal conductance.We retrieve fraction of PAR absorbed by chlorophyll (fAPARchl) with an advanced canopy-leaf-soil-snow-water coupled radiative transfer model. Most ecological models and land-surface models that simulate vegetation GPP with remote sensing data utilize fraction of PAR absorbed by the whole canopy (fAPARcanopy). However, only the PAR absorbed by chlorophyll is potentially available for photosynthesis since the PAR absorbed by non-photosynthetic vegetation section (NPV) of the canopy is not used for photosynthesis. Therefore, fAPARchl (rather than fAPARcanopy) should be utilized to estimate fAPAR for photosynthesis (fAPARPSN), and thus in GPP simulation. Globally selected sites include those sites in tropical, Arctic/boreal, coastal, and wetland-dominant regions. The fAPARchl and fAPARcanopy products for a surrounding area 50 km x 50 km of each site are mapped. The fAPARchl is utilized to estimate GPP, and compared to tower flux GPP for validation. The GPP estimation performance with fAPARchl is also compared with the GPP estimation performance with MOD15A2 FPAR. The fAPARchl product is further implemented into ecological models and land-surface models to simulate vegetation GPP. NDVI is the other proxy of fAPARPSN in GPP estimation. We quantify the uncertainties in estimates of fAPARPSN when approximated with fAPARcanopy and NDVI. The uncertainties are significant and vary spatially, temporally, and with plant functional types.

How tropical cyclone inter-annual timing and trajectory control gross primary productivity in the SE US at seasonal and annual timescales and impacts on mountain forest eco-hydrology

NASA Astrophysics Data System (ADS)

Lowman, L.; Barros, A.

2015-12-01

Tropical cyclones (TCs) are an important source of freshwater input to the SE US eco-hydrologic function. Soil moisture, a temporal integral of precipitation, is critical to plant photosynthesis and carbon assimilation. In this study, we investigate the impact TCs have on gross primary productivity (GPP) in the SE US using the physically-based Duke Coupled Hydrology Model with Vegetation (DCHM-V) which includes coupled water and energy cycles and a biochemical representation of photosynthesis. A parsimonious evaluation of model-estimated GPP against all available AmeriFlux data in the SE US is presented. We characterize the seasonality of vegetation activity in the SE US by simulating water, energy, and carbon fluxes using the DCHM-V at high spatial (4 km) and temporal (30-min) resolution over the period 2002 - 2012. The model is run offline using atmospheric forcing data from NLDAS-2, precipitation from StageIV, and phenology indices from MODIS FPAR/LAI. Analysis of model results show the tendency for low GPP to occur in the Appalachian Mountains during peak summer months when water stress limits stomatal function. We contrast these simulations with model runs where periods of TC activity are replaced with the monthly climatological diurnal cycle from NARR. Results show that the timing and trajectory of TCs are key to understanding their impact on GPP across the SE US. Specifically: 1) Timing of moisture input from TCs greatly influences the vegetation response. TCs during peak summer months increase GPP and years with TCs falling in peak summer months see much higher annual GPP averages; 2) Years of drought and low plant productivity (2006-2007, 2011-2012) in the SE US tend to have TCs that fall later in the year when the additional moisture input does not have a significant impact on vegetation activity; and 3) TC path impacts regional GPP averages. The mountain region shows large inter- and intra-annual variability in plant productivity and high sensitivity to water stress. The Appalachian mountain region tends to have higher GPP when TC trajectories are closer in proximity.

Concurrent Transient Activation of Wnt/{beta}-Catenin Pathway Prevents Radiation Damage to Salivary Glands

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hai Bo; Yang Zhenhua; Shangguan Lei

2012-05-01

Purpose: Many head and neck cancer survivors treated with radiotherapy suffer from permanent impairment of their salivary gland function, for which few effective prevention or treatment options are available. This study explored the potential of transient activation of Wnt/{beta}-catenin signaling in preventing radiation damage to salivary glands in a preclinical model. Methods and Materials: Wnt reporter transgenic mice were exposed to 15 Gy single-dose radiation in the head and neck area to evaluate the effects of radiation on Wnt activity in salivary glands. Transient Wnt1 overexpression in basal epithelia was induced in inducible Wnt1 transgenic mice before together with, after,more » or without local radiation, and then saliva flow rate, histology, apoptosis, proliferation, stem cell activity, and mRNA expression were evaluated. Results: Radiation damage did not significantly affect activity of Wnt/{beta}-catenin pathway as physical damage did. Transient expression of Wnt1 in basal epithelia significantly activated the Wnt/{beta}-catenin pathway in submandibular glands of male mice but not in those of females. Concurrent transient activation of the Wnt pathway prevented chronic salivary gland dysfunction following radiation by suppressing apoptosis and preserving functional salivary stem/progenitor cells. In contrast, Wnt activation 3 days before or after irradiation did not show significant beneficial effects, mainly due to failure to inhibit acute apoptosis after radiation. Excessive Wnt activation before radiation failed to inhibit apoptosis, likely due to extensive induction of mitosis and up-regulation of proapoptosis gene PUMA while that after radiation might miss the critical treatment window. Conclusion: These results suggest that concurrent transient activation of the Wnt/{beta}-catenin pathway could prevent radiation-induced salivary gland dysfunction.« less

Spaceflight Radiation Health program at the Lyndon B. Johnson Space Center

NASA Technical Reports Server (NTRS)

Johnson, A. Steve; Badhwar, Gautam D.; Golightly, Michael J.; Hardy, Alva C.; Konradi, Andrei; Yang, Tracy Chui-Hsu

1993-01-01

The Johnson Space Center leads the research and development activities that address the health effects of space radiation exposure to astronaut crews. Increased knowledge of the composition of the environment and of the biological effects of space radiation is required to assess health risks to astronaut crews. The activities at the Johnson Space Center range from quantification of astronaut exposures to fundamental research into the biological effects resulting from exposure to high energy particle radiation. The Spaceflight Radiation Health Program seeks to balance the requirements for operational flexibility with the requirement to minimize crew radiation exposures. The components of the space radiation environment are characterized. Current and future radiation monitoring instrumentation is described. Radiation health risk activities are described for current Shuttle operations and for research development program activities to shape future analysis of health risk.

NF-κB functions as a molecular link between tumor cells and Th1/Tc1 T cells in the tumor microenvironment to exert radiation-mediated tumor suppression

PubMed Central

Simon, Priscilla S.; Bardhan, Kankana; Chen, May R.; Paschall, Amy V.; Lu, Chunwan; Bollag, Roni J.; Kong, Feng-Chong; Jin, JianYue; Kong, Feng-Ming; Waller, Jennifer L.; Pollock, Raphael E.; Liu, Kebin

2016-01-01

Radiation modulates both tumor cells and immune cells in the tumor microenvironment to exert its anti-tumor activity; however, the molecular connection between tumor cells and immune cells that mediates radiation-exerted tumor suppression activity in the tumor microenvironment is largely unknown. We report here that radiation induces rapid activation of the p65/p50 and p50/p50 NF-κB complexes in human soft tissue sarcoma (STS) cells. Radiation-activated p65/p50 and p50/p50 bind to the TNFα promoter to activate its transcription in STS cells. Radiation-induced TNFα induces tumor cell death in an autocrine manner. A sublethal dose of Smac mimetic BV6 induces cIAP1 and cIAP2 degradation to increase tumor cell sensitivity to radiation-induced cell death in vitro and to enhance radiation-mediated suppression of STS xenografts in vivo. Inhibition of caspases, RIP1, or RIP3 blocks radiation/TNFα-induced cell death, whereas inhibition of RIP1 blocks TNFα-induced caspase activation, suggesting that caspases and RIP1 act sequentially to mediate the non-compensatory cell death pathways. Furthermore, we determined in a syngeneic sarcoma mouse model that radiation up-regulates IRF3, IFNβ, and the T cell chemokines CCL2 and CCL5 in the tumor microenvironment, which are associated with activation and increased infiltration of Th1/Tc1 T cells in the tumor microenvironment. Moreover, tumor-infiltrating T cells are in their active form since both the perforin and FasL pathways are activated in irradiated tumor tissues. Consequently, combined BV6 and radiation completely suppressed tumor growth in vivo. Therefore, radiation-induced NF-κB functions as a molecular link between tumor cells and immune cells in the tumor microenvironment for radiation-mediated tumor suppression. PMID:27014915

BOREAS Level-3a Landsat TM Imagery: Scaled At-sensor Radiance in BSQ Format

NASA Technical Reports Server (NTRS)

Nickerson, Jaime; Hall, Forrest G. (Editor); Knapp, David; Newcomer, Jeffrey A.; Cihlar, Josef

2000-01-01

For BOREAS, the level-3a Landsat TM data, along with the other remotely sensed images, were collected in order to provide spatially extensive information over the primary study areas. This information includes radiant energy, detailed land cover, and biophysical parameter maps such as FPAR and LAI. Although very similar in content to the level-3s Landsat TM products, the level-3a images were created to provide users with a more usable BSQ format and to provide information that permitted direct determination of per-pixel latitude and longitude coordinates. Geographically, the level-3a images cover the BOREAS NSA and SSA. Temporally, the images cover the period of 22-Jun-1984 to 30-Jul-1996. The images are available in binary, image-format files. With permission from CCRS and RSI, several of the full-resolution images are included on the BOREAS CD-ROM series. Due to copyright issues, the images not included on the CD-ROM may not be publicly available. See Sections 15 and 16 for information about how to acquire the data. Information about the images not on the CD-ROMs is provided in an inventory listing on the CD-ROMs.

Charged particle detectors with active detector surface for partial energy deposition of the charged particles and related methods

DOEpatents

Gerts, David W; Bean, Robert S; Metcalf, Richard R

2013-02-19

A radiation detector is disclosed. The radiation detector comprises an active detector surface configured to generate charge carriers in response to charged particles associated with incident radiation. The active detector surface is further configured with a sufficient thickness for a partial energy deposition of the charged particles to occur and permit the charged particles to pass through the active detector surface. The radiation detector further comprises a plurality of voltage leads coupled to the active detector surface. The plurality of voltage leads is configured to couple to a voltage source to generate a voltage drop across the active detector surface and to separate the charge carriers into a plurality of electrons and holes for detection. The active detector surface may comprise one or more graphene layers. Timing data between active detector surfaces may be used to determine energy of the incident radiation. Other apparatuses and methods are disclosed herein.

Radiation Protection, Safety and Security Issues in Ghana.

PubMed

Boadu, Mary; Emi-Reynolds, Geoffrey; Amoako, Joseph Kwabena; Akrobortu, Emmanuel; Hasford, Francis

2016-11-01

Although the use of radioisotopes in Ghana began in 1952, the Radiation Protection Board of Ghana was established in 1993 and served as the national competent authority for authorization and inspection of practices and activities involving radiation sources until 2015. The law has been superseded by an Act of Parliament, Act 895 of 2015, mandating the Nuclear Regulatory Authority of Ghana to take charge of the regulation of radiation sources and their applications. The Radiation Protection Institute in Ghana provided technical support to the regulatory authority. Regulatory and service activities that were undertaken by the Institute include issuance of permits for handling of a radiation sources, authorization and inspection of radiation sources, radiation safety assessment, safety assessment of cellular signal towers, and calibration of radiation-emitting equipment. Practices and activities involving application of radiation are brought under regulatory control in the country through supervision by the national competent authority.

Activating PTEN by COX-2 inhibitors antagonizes radiation-induced AKT activation contributing to radiosensitization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meng, Zhen; Department of Oral & Maxillofacial Surgery, Peking University School and Hospital of Stomatology, 22 Zhongguancun Avenue South, Haidian District, Beijing 100081; Gan, Ye-Hua, E-mail: kqyehuagan@bjmu.edu.cn

2015-05-01

Radiotherapy is still one of the most effective nonsurgical treatments for many tumors. However, radioresistance remains a major impediment to radiotherapy. Although COX-2 inhibitors can induce radiosensitization, the underlying mechanism is not fully understood. In this study, we showed that COX-2 selective inhibitor celecoxib enhanced the radiation-induced inhibition of cell proliferation and apoptosis in HeLa and SACC-83 cells. Treatment with celecoxib alone dephosphorylated phosphatase and tensin homolog deleted on chromosome ten (PTEN), promoted PTEN membrane translocation or activation, and correspondingly dephosphorylated or inactivated protein kinase B (AKT). By contrast, treatment with radiation alone increased PTEN phosphorylation, inhibited PTEN membrane translocationmore » and correspondingly activated AKT in the two cell lines. However, treatment with celecoxib or another COX-2 selective inhibitor (valdecoxib) completely blocked radiation-induced increase of PTEN phosphorylation, rescued radiation-induced decrease in PTEN membrane translocation, and correspondingly inactivated AKT. Moreover, celecoxib could also upregulate PTEN protein expression by downregulating Sp1 expression, thereby leading to the activation of PTEN transcription. Our results suggested that COX-2 inhibitors could enhance radiosensitization at least partially by activating PTEN to antagonize radiation-induced AKT activation. - Highlights: • COX-2 inhibitor, celecoxib, could enhance radiosensitization. • Radiation induced PTEN inactivation (phosphorylation) and AKT activation. • COX-2 inhibitor induced PTEN expression and activation, and inactivated AKT. • COX-2 inhibitor enhanced radiosensitization through activating PTEN.« less

Universal EUV in-band intensity detector

DOEpatents

Berger, Kurt W.

2004-08-24

Extreme ultraviolet light is detected using a universal in-band detector for detecting extreme ultraviolet radiation that includes: (a) an EUV sensitive photodiode having a diode active area that generates a current responsive to EUV radiation; (b) one or more mirrors that reflects EUV radiation having a defined wavelength(s) to the diode active area; and (c) a mask defining a pinhole that is positioned above the diode active area, wherein EUV radiation passing through the pinhole is restricted substantially to illuminating the diode active area.

Radiation protection for manned space activities

NASA Technical Reports Server (NTRS)

Jordan, T. M.

1983-01-01

The Earth's natural radiation environment poses a hazard to manned space activities directly through biological effects and indirectly through effects on materials and electronics. The following standard practices are indicated that address: (1) environment models for all radiation species including uncertainties and temporal variations; (2) upper bound and nominal quality factors for biological radiation effects that include dose, dose rate, critical organ, and linear energy transfer variations; (3) particle transport and shielding methodology including system and man modeling and uncertainty analysis; (4) mission planning that includes active dosimetry, minimizes exposure during extravehicular activities, subjects every mission to a radiation review, and specifies operational procedures for forecasting, recognizing, and dealing with large solar flaes.

Exposure to Heavy Ion Radiation Induces Persistent Oxidative Stress in Mouse Intestine

PubMed Central

Datta, Kamal; Suman, Shubhankar; Kallakury, Bhaskar V. S.; Fornace, Albert J.

2012-01-01

Ionizing radiation-induced oxidative stress is attributed to generation of reactive oxygen species (ROS) due to radiolysis of water molecules and is short lived. Persistent oxidative stress has also been observed after radiation exposure and is implicated in the late effects of radiation. The goal of this study was to determine if long-term oxidative stress in freshly isolated mouse intestinal epithelial cells (IEC) is dependent on radiation quality at a dose relevant to fractionated radiotherapy. Mice (C57BL/6J; 6 to 8 weeks; female) were irradiated with 2 Gy of γ-rays, a low-linear energy transfer (LET) radiation, and intestinal tissues and IEC were collected 1 year after radiation exposure. Intracellular ROS, mitochondrial function, and antioxidant activity in IEC were studied by flow cytometry and biochemical assays. Oxidative DNA damage, cell death, and mitogenic activity in IEC were assessed by immunohistochemistry. Effects of γ radiation were compared to 56Fe radiation (iso-toxic dose: 1.6 Gy; energy: 1000 MeV/nucleon; LET: 148 keV/µm), we used as representative of high-LET radiation, since it's one of the important sources of high Z and high energy (HZE) radiation in cosmic rays. Radiation quality affected the level of persistent oxidative stress with higher elevation of intracellular ROS and mitochondrial superoxide in high-LET 56Fe radiation compared to unirradiated controls and γ radiation. NADPH oxidase activity, mitochondrial membrane damage, and loss of mitochondrial membrane potential were greater in 56Fe-irradiated mice. Compared to γ radiation oxidative DNA damage was higher, cell death ratio was unchanged, and mitotic activity was increased after 56Fe radiation. Taken together our results indicate that long-term functional dysregulation of mitochondria and increased NADPH oxidase activity are major contributing factors towards heavy ion radiation-induced persistent oxidative stress in IEC with potential for neoplastic transformation. PMID:22936983

[Effects of Light Near-Infrared Radiation on Rats Assessed by Succinate Dehydrogenase Activity in Lymphocytes on Blood Smears].

PubMed

Khunderyakova, N V; Zakharchenko, A V; Zakharchenko, M V; Muller, H; Fedotcheva, I; Kondrashova, M N

2015-01-01

Biological effects of light near infrared radiation (850 nm), with modulation acoustic frequency of 101 Hz, was studied. The study was conducted on rats, the effect was recorded by succinate dehydrogenase activity in lymphocytes on the blood smear after administration of the activating dose of adrenaline, which simulates the state of the organism in the early stages of the pathogenic effects (stress). A pronounced regulating effect of infrared radiation on the activity of succinate dehydrogenase in animals activated by adrenaline was shown. Infrared radiation has a normalizing effect reducing the degree of inhibition or activation of the enzyme induced by adrenaline and had no effect on the control animals. Thus, by modulating the activity of succinate dehydrogenase infrared radiation regulates energy production in the mitochondria supported by the most powerful oxidation substrate--succinic acid, which is especially pronounced under stress.

CONNECTION BETWEEN THE INCREASED FIBRINOGEN CONCENTRATION IN DOGS WITH RADIATION SICKNESS AND THE FIBRINOGENASE ACTIVITY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gordeeva, K.V.

1963-11-01

A study was made of the concentration of blood plasma fibrinogen in relation to the changes of fibrinogenase activity. Dogs with radiation sickness (severe, moderately severe, and mild) served as experimental animals. A rise of the blood plasma fibrinogen content was observed in dogs with severe and moderately severe radiation sickness. This phenomenon is especially pronounced at the height of radiation sickness. The activity of fibrinogenase in severe radiation sickness was considerably decreased at the initial period and at the height of the disease. The rise of fibrinogen content in severe and moderately severe radiation sickness should be regarded asmore » an adaptive reaction directed to control hemorrhages, not as the sequence of raduced fibrinogenase activity. (auth)« less

Gamma radiation combined with cinnamon oil to maintain fish quality

NASA Astrophysics Data System (ADS)

Lyu, Fei; Zhang, Jing; Wei, Qianqian; Gao, Fei; Ding, Yuting; Liu, Shulai

2017-12-01

Effects of gamma radiation combined with cinnamon oil on quality of Northern Snakehead fish fillets were observed during storage at 4 °C. Fish fillets were treated with 1-5 kGy gamma radiation, 0.05-0.5% cinnamon oil or the combination of radiation and cinnamon oil. The antimicrobial activity increased with radiation dose and cinnamon oil concentration. During storage, the combination of 1 kGy radiation and 0.5% cinnamon oil displayed better inhibiting activities on aerobic plate counts, total volatile basic nitrogen, thiobarbituric acid reaction substances than 1 kGy radiation or 0.5% cinnamon oil used alone. Moreover, the combination could arrive at the similar inhibiting activities of cinnamon oil with higher concentration of 0.5% or radiation with higher dose of 5 kGy. Thus, the combination could decrease the radiation dose and cinnamon oil concentration without decreasing the effect of them on maintaining fish quality.

Parametric Study of Variable Emissivity Radiator Surfaces

NASA Technical Reports Server (NTRS)

Grob, Lisa M.; Swanson, Theodore D.

2000-01-01

The goal of spacecraft thermal design is to accommodate a high function satellite in a low weight and real estate package. The extreme environments that the satellite is exposed during its orbit are handled using passive and active control techniques. Heritage passive heat rejection designs are sized for the hot conditions and augmented for the cold end with heaters. The active heat rejection designs to date are heavy, expensive and/or complex. Incorporating an active radiator into the design that is lighter, cheaper and more simplistic will allow designers to meet the previously stated goal of thermal spacecraft design Varying the radiator's surface properties without changing the radiating area (as with VCHP), or changing the radiators' views (traditional louvers) is the objective of the variable emissivity (vary-e) radiator technologies. A parametric evaluation of the thermal performance of three such technologies is documented in this paper. Comparisons of the Micro-Electromechanical Systems (MEMS), Electrochromics, and Electrophoretics radiators to conventional radiators, both passive and active are quantified herein. With some noted limitations, the vary-e radiator surfaces provide significant advantages over traditional radiators and a promising alternative design technique for future spacecraft thermal systems.

Curcumin Modulates the Radiosensitivity of Colorectal Cancer Cells by Suppressing Constitutive and Inducible NF-{kappa}B Activity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sandur, Santosh K.; Deorukhkar, Amit; Pandey, Manoj K.

2009-10-01

Purpose: Radiation therapy is an integral part of the preoperative treatment of rectal cancers. However, only a minority of patients achieve a complete pathologic response to therapy because of resistance of these tumors to radiation therapy. This resistance may be mediated by constitutively active pro-survival signaling pathways or by inducible/acquired mechanisms in response to radiation therapy. Simultaneous inhibition of these pathways can sensitize these tumors to radiation therapy. Methods and Materials: Human colorectal cancer cells were exposed to clinically relevant doses of gamma rays, and the mechanism of their radioresistance was investigated. We characterized the transcription factor nuclear factor-{kappa}B (NF-{kappa}B)more » activation as a mechanism of inducible radioresistance in colorectal cancer and used curcumin, the active ingredient in the yellow spice turmeric, to overcome this resistance. Results: Curcumin inhibited the proliferation and the post-irradiation clonogenic survival of multiple colorectal cancer cell lines. Radiation stimulated NF-{kappa}B activity in a dose- and time-dependent manner, whereas curcumin suppressed this radiation-induced NF-{kappa}B activation via inhibition of radiation-induced phosphorylation and degradation of inhibitor of {kappa}B alpha, inhibition of inhibitor of {kappa}B kinase activity, and inhibition of Akt phosphorylation. Curcumin also suppressed NF-{kappa}B-regulated gene products (Bcl-2, Bcl-x{sub L}, inhibitor of apoptosis protein-2, cyclooxygenase-2, and cyclin D1). Conclusions: Our results suggest that transient inducible NF-{kappa}B activation provides a prosurvival response to radiation that may account for development of radioresistance. Curcumin blocks this signaling pathway and potentiates the antitumor effects of radiation therapy.« less

[Effect of low-intensity 900 MHz frequency electromagnetic radiation on rat liver and blood serum enzyme activities].

PubMed

Nersesova, L S; Petrosian, M S; Gazariants, M G; Mkrtchian, Z S; Meliksetian, G O; Pogosian, L G; Akopian, Zh I

2014-01-01

The comparative analysis of the rat liver and blood serum creatine kinase, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and purine nucleoside phosphorylase post-radiation activity levels after a total two-hour long single and fractional exposure of the animals to low-intensity 900 MHz frequency electromagnetic field showed that the most sensitive enzymes to the both schedules of radiation are the liver creatine kinase, as well as the blood serum creatine kinase and alkaline phosphatase. According to the comparative analysis of the dynamics of changes in the activity level of the liver and blood serum creatine kinase, alanine aminotransferase, aspartate aminotransferase and purine nucleoside phosphorylase, both single and fractional radiation schedules do not affect the permeability of a hepatocyte cell membrane, but rather cause changes in their energetic metabolism. The correlation analysis of the post-radiation activity level changes of the investigated enzymes did not reveal a clear relationship between them. The dynamics of post-radiation changes in the activity of investigated enzyme levels following a single and short-term fractional schedules of radiation did not differ essentially.

Frequency-independent radiation modes of interior sound radiation: Experimental study and global active control

NASA Astrophysics Data System (ADS)

Hesse, C.; Papantoni, V.; Algermissen, S.; Monner, H. P.

2017-08-01

Active control of structural sound radiation is a promising technique to overcome the poor passive acoustic isolation performance of lightweight structures in the low-frequency region. Active structural acoustic control commonly aims at the suppression of the far-field radiated sound power. This paper is concerned with the active control of sound radiation into acoustic enclosures. Experimental results of a coupled rectangular plate-fluid system under stochastic excitation are presented. The amplitudes of the frequency-independent interior radiation modes are determined in real-time using a set of structural vibration sensors, for the purpose of estimating their contribution to the acoustic potential energy in the enclosure. This approach is validated by acoustic measurements inside the cavity. Utilizing a feedback control approach, a broadband reduction of the global acoustic response inside the enclosure is achieved.

Acute Cerebrovascular Radiation Syndrome: Radiation Neurotoxicity , mechanisms of CNS radiation injury, advanced countermeasures for Radiation Protection of Central Nervous System.

NASA Astrophysics Data System (ADS)

Popov, Dmitri; Jones, Jeffrey; Maliev, Slava

Key words: Cerebrovascular Acute Radiation Syndrome (Cv ARS), Radiation Neurotoxins (RNT), Neurotransmitters, Radiation Countermeasures, Antiradiation Vaccine (ArV), Antiradiation Blocking Antibodies, Antiradiation Antidote. Psychoneuroimmunology, Neurotoxicity. ABSTRACT: To review the role of Radiation Neurotoxins in triggering, developing of radiation induced central nervous system injury. Radiation Neurotoxins - rapidly acting blood toxic lethal agent, which activated after irradiation and concentrated, circulated in interstitial fluid, lymph, blood with interactions with cell membranes, receptors and cell compartments. Radiation Neurotoxins - biological molecules with high enzymatic activity and/or specific lipids and activated or modified after irradiation. The Radiation Neurotoxins induce increased permeability of blood vessels, disruption of the blood-brain barrier, blood-cerebrospinal fluid (CSF) barrier and developing severe disorder of blood macro- and micro-circulation. Principles of Radiation Psychoneuro-immunology and Psychoneuro-allergology were applied for determination of pathological processes developed after irradiation or selective administration of Radiation Neurotoxins to radiation naïve mammals. Effects of radiation and exposure to radiation can develop severe irreversible abnormalities of Central Nervous System, brain structures and functions. Antiradiation Vaccine - most effective, advanced methods of protection, prevention, mitigation and treatment and was used for of Acute Radiation Syndromes and elaboration of new technology for immune-prophylaxis and immune-protection against ϒ, Heavy Ion, Neutron irradiation. Results of experiments suggested that blocking, antitoxic, antiradiation antibodies can significantly reduce toxicity of Radiation Toxins. New advanced technology include active immune-prophylaxis with Antiradiation Vaccine and Antiradiation therapy that included specific blocking antibodies to Radiation Neurotoxins. Antiradiation Vaccine and Antiradiation IgG preparations - prospective effective antidote/countermeasure for ϒ-irradiation, heavy ions irradiation, neutron irradiation. Recommendations for treatment and immune-prophylaxis of CNS injury, induced by radiation, were proposed. Specific immune therapy and specific immune prophylaxis reduce symptoms of ACvRS. This manuscript summarizes the results of experiments and considering possibility for blocking toxicological mechanisms of action of Radiation and Radiation Neurotoxins and prevention or diminishing clinical signs of injury of CNS. Experimental data suggest that Antiradiation vaccine and Antiradiation IgG with specific antibodies to Radiation Neurotoxins, Cytotoxins protect CNS against high doses of radiation.

DNA Topoisomerase IB as a Potential Ionizing Radiation Exposure and Dose Biomarker.

PubMed

Daudee, Rotem; Gonen, Rafi; German, Uzi; Orion, Itzhak; Alfassi, Zeev B; Priel, Esther

2018-06-01

In radiation exposure scenarios where physical dosimetry is absent or inefficient, dose estimation must rely on biological markers. A reliable biomarker is of utmost importance in correlating biological system changes with radiation exposure. Human DNA topoisomerase ІB (topo І) is a ubiquitous nuclear enzyme, which is involved in essential cellular processes, including transcription, DNA replication and DNA repair, and is the target of anti-cancer drugs. It has been shown that the cellular activity of this enzyme is significantly sensitive to various DNA lesions, including radiation-induced DNA damages. Therefore, we investigated the potential of topo I as a biomarker of radiation exposure and dose. We examined the effect of exposure of different human cells to beta, X-ray and gamma radiation on the cellular catalytic activity of topo I. The results demonstrate a significant reduction in the DNA relaxation activity of topo I after irradiation and the level of the reduction was correlated with radiation dose. In normal human peripheral blood lymphocytes, exposure for 3 h to an integral dose of 0.065 mGy from tritium reduced the enzyme activity to less than 25%. In MG-63 osteoblast-like cells and in human pulmonary fibroblast (HPF) cells exposed to gamma radiation from a 60 Co source (up to 2 Gy) or to X rays (up to 2.8 Gy), a significant decrease in topo I catalytic activity was also observed. We observed that the enzyme-protein level was not altered but was partially posttranslational modified by ADP-ribosylation of the enzyme protein that is known to reduce topo I activity. The results of this study suggest that the decrease in the cellular topo I catalytic activity after low-dose exposure to different radiation types may be considered as a novel biomarker of ionizing radiation exposure and dose. For this purpose, a suitable ELISA-based method for large-scale analysis of radiation-induced topo I modification is under development.

Acetylcholine content and cholinesterase activity as related to the combined effects of allergen and radiation. [Rats, gamma radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lipshits, R.U.; Kratinova, M.A.

1977-01-01

Rats were given intraperitoneal injections of antigen and exposed to 200 R of gamma radiation. Acetylcholine content and cholinesterase activity of blood were analyzed every 5 days for 30 days. The interval between sensitization and irradiation determined the direction of changes in allergic reactions. The radiation appreciably attenuated active sensitization of rats. The degree of sensitization was related to changes in cholinergic processes. The data confirmed the assumption that cholinergic systems are involved in the mechanisms of change in allergic reactivity under the influence of radiation. (HLW)

Radiation Measurements Performed with Active Detectors Relevant for Human Space Exploration

PubMed Central

Narici, Livio; Berger, Thomas; Matthiä, Daniel; Reitz, Günther

2015-01-01

A reliable radiation risk assessment in space is a mandatory step for the development of countermeasures and long-duration mission planning in human spaceflight. Research in radiobiology provides information about possible risks linked to radiation. In addition, for a meaningful risk evaluation, the radiation exposure has to be assessed to a sufficient level of accuracy. Consequently, both the radiation models predicting the risks and the measurements used to validate such models must have an equivalent precision. Corresponding measurements can be performed both with passive and active devices. The former is easier to handle, cheaper, lighter, and smaller but they measure neither the time dependence of the radiation environment nor some of the details useful for a comprehensive radiation risk assessment. Active detectors provide most of these details and have been extensively used in the International Space Station. To easily access such an amount of data, a single point access is becoming essential. This review presents an ongoing work on the development of a tool that allows obtaining information about all relevant measurements performed with active detectors providing reliable inputs for radiation model validation. PMID:26697408

Radiation Measurements Performed with Active Detectors Relevant for Human Space Exploration.

PubMed

Narici, Livio; Berger, Thomas; Matthiä, Daniel; Reitz, Günther

2015-01-01

A reliable radiation risk assessment in space is a mandatory step for the development of countermeasures and long-duration mission planning in human spaceflight. Research in radiobiology provides information about possible risks linked to radiation. In addition, for a meaningful risk evaluation, the radiation exposure has to be assessed to a sufficient level of accuracy. Consequently, both the radiation models predicting the risks and the measurements used to validate such models must have an equivalent precision. Corresponding measurements can be performed both with passive and active devices. The former is easier to handle, cheaper, lighter, and smaller but they measure neither the time dependence of the radiation environment nor some of the details useful for a comprehensive radiation risk assessment. Active detectors provide most of these details and have been extensively used in the International Space Station. To easily access such an amount of data, a single point access is becoming essential. This review presents an ongoing work on the development of a tool that allows obtaining information about all relevant measurements performed with active detectors providing reliable inputs for radiation model validation.

Eckol protects V79-4 lung fibroblast cells against gamma-ray radiation-induced apoptosis via the scavenging of reactive oxygen species and inhibiting of the c-Jun NH(2)-terminal kinase pathway.

PubMed

Zhang, Rui; Kang, Kyoung Ah; Piao, Mei Jing; Ko, Dong Ok; Wang, Zhi Hong; Lee, In Kyung; Kim, Bum Joon; Jeong, Il Yun; Shin, Taekyun; Park, Jae Woo; Lee, Nam Ho; Hyun, Jin Won

2008-09-04

The radioprotective effect of eckol against gamma-ray radiation-induced oxidative stress and its possible protective mechanisms were investigated. Eckol was found to reduce the intracellular reactive oxygen species generated by gamma-ray radiation. Moreover, eckol also protected against radiation-induced cellular DNA damage and membrane lipid peroxidation, which are the main targets of radiation-induced damage. In addition, eckol recovered the cell viability damaged by radiation via the inhibition of apoptosis. Irradiated cells with eckol treatment reduced the expression of bax, the activation of caspase 9 and caspase 3, which were induced by radiation. However, irradiated cells with eckol recovered the expression of bcl-2 and mitochondrial cytochrome c which were decreased by radiation. The anti-apoptotic effect of eckol exerted via the inhibition of mitogen-activated protein kinase kinase-4 (MKK4/SEK1)-c-Jun NH(2)-terminal kinase (JNK)-activator protein 1 (AP-1) cascades induced by radiation. In summary, the results suggest that eckol protects cells against the oxidative stress induced by radiation via the reduction of reactive oxygen species and the attenuation of activation in SEK1-JNK-AP-1 pathway.

Effects of GSM-Frequency Electromagnetic Radiation on Some Physiological and Biochemical Parameters in Rats.

PubMed

Khirazova, E E; Baizhumanov, A A; Trofimova, L K; Deev, L I; Maslova, M V; Sokolova, N A; Kudryashova, N Yu

2012-10-01

Single exposure of white outbred rats to electromagnetic radiation with a frequency 905 MHz (GSM frequency) for 2 h increased anxiety, reduced locomotor, orientation, and exploration activities in females and orientation and exploration activities in males. Glucocorticoid levels and antioxidant system activity increased in both males and females. In addition to acute effects, delayed effects of radiation were observed in both males and females 1 day after the exposure. These results demonstrated significant effect of GSM-range radiation on the behavior and activity of stress-realizing and stress-limiting systems of the body.

Infra-red signature neutron detector

DOEpatents

Bell, Zane William [Oak Ridge, TN; Boatner, Lynn Allen [Oak Ridge, TN

2009-10-13

A method of detecting an activator, the method including impinging with an activator a receptor material that includes a photoluminescent material that generates infrared radiation and generation a by-product of a nuclear reaction due to the activator impinging the receptor material. The method further includes generating light from the by-product via the Cherenkov effect, wherein the light activates the photoluminescent material so as to generate the infrared radiation. Identifying a characteristic of the activator based on the infrared radiation.

Resonant infrared detector with substantially unit quantum efficiency

NASA Technical Reports Server (NTRS)

Farhoomand, Jam (Inventor); Mcmurray, Robert E., Jr. (Inventor)

1994-01-01

A resonant infrared detector includes an infrared-active layer which has first and second parallel faces and which absorbs radiation of a given wavelength. The detector also includes a first tuned reflective layer, disposed opposite the first face of the infrared-active layer, which reflects a specific portion of the radiation incident thereon and allows a specific portion of the incident radiation at the given wavelength to reach the infrared-active layer. A second reflective layer, disposed opposite the second face of the infrared-active layer, reflects back into the infrared-active layer substantially all of the radiation at the given wavelength which passes through the infrared-active layer. The reflective layers have the effect of increasing the quantum efficiency of the infrared detector relative to the quantum efficiency of the infrared-active layer alone.

NLRP3 inflammasome activation mediates radiation-induced pyroptosis in bone marrow-derived macrophages

PubMed Central

Liu, Yan-gang; Chen, Ji-kuai; Zhang, Zi-teng; Ma, Xiu-juan; Chen, Yong-chun; Du, Xiu-ming; Liu, Hong; Zong, Ying; Lu, Guo-cai

2017-01-01

A limit to the clinical benefit of radiotherapy is not an incapacity to eliminate tumor cells but rather a limit on its capacity to do so without destroying normal tissue and inducing inflammation. Recent evidence reveals that the inflammasome is essential for mediating radiation-induced cell and tissue damage. In this study, using primary cultured bone marrow-derived macrophages (BMDM) and a mouse radiation model, we explored the role of NLRP3 inflammasome activation and the secondary pyroptosis underlying radiation-induced immune cell death. We observed an increasing proportion of pyroptosis and elevating Caspase-1 activation in 10 and 20 Gy radiation groups. Nlrp3 knock out significantly diminished the quantity of cleaved-Caspase-1 (p10) and IL-1β as well as the proportion of pyroptosis. Additionally, in vivo research shows that 9.5 Gy of radiation promotes Caspase-1 activation in marginal zone cells and induces death in mice, both of which can be significantly inhibited by knocking out Nlrp3. Thus, based on these findings, we conclude that the NLRP3 inflammasome activation mediates radiation-induced pyroptosis in BMDMs. Targeting NLRP3 inflammasome and pyroptosis may serve as effective strategies to diminish injury caused by radiation. PMID:28151471

A passive and active microwave-vector radiative transfer (PAM-VRT) model

NASA Astrophysics Data System (ADS)

Yang, Jun; Min, Qilong

2015-11-01

A passive and active microwave vector radiative transfer (PAM-VRT) package has been developed. This fast and accurate forward microwave model, with flexible and versatile input and output components, self-consistently and realistically simulates measurements/radiation of passive and active microwave sensors. The core PAM-VRT, microwave radiative transfer model, consists of five modules: gas absorption (two line-by-line databases and four fast models); hydrometeor property of water droplets and ice (spherical and nonspherical) particles; surface emissivity (from Community Radiative Transfer Model (CRTM)); vector radiative transfer of successive order of scattering (VSOS); and passive and active microwave simulation. The PAM-VRT package has been validated against other existing models, demonstrating good accuracy. The PAM-VRT not only can be used to simulate or assimilate measurements of existing microwave sensors, but also can be used to simulate observation results at some new microwave sensors.

The c-Abl signaling network in the radioadaptive response

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chi-Min, Yuan

2014-01-28

The radioadaptive response, or radiation hormesis, i.e. a low dose of radiation can protect cells and organisms from the effects of a subsequent higher dose, is a widely recognized phenomenon. Mechanisms underlying such radiation hormesis, however, remain largely unclear. Preliminary studies indicate an important role of c-Abl signaling in mediating the radioadaptive response. We propose to investigate how c-Abl regulates the crosstalk between p53 and NFκB in response to low doses irradiation. We found in our recent study that low dose IR induces a reciprocal p53 suppression and NFκB activation, which induces HIF-a and subsequently a metabolic reprogramming resulting inmore » a transition from oxidative phosphorylation to glycolysis. Of importance is that this glycolytic switch is essential for the radioadaptive response. This low-dose radiationinduced HIF1α activation was in sharp contrast with the high-dose IR-induced p53 activation and HIF1α inhibition. HIF1α and p53 seem to play distinct roles in mediating the radiation dose-dependent metabolic response. The induction of HIF1α-mediated glycolysis is restricted to a low dose range of radiation, which may have important implications in assessing the level of radiation exposure and its potential health risk. Our results support a dose-dependent metabolic response to IR. When IR doses are below the threshold of causing detectable DNA damage (<0.2Gy) and thus little p53 activation, HIF1α is induced resulting in induction of glycolysis and increased radiation resistance. When the radiation dose reaches levels eliciting DNA damage, p53 is activated and diminishes the activity of HIF1α and glycolysis, leading to the induction of cell death. Our work challenges the LNT model of radiation exposure risk and provides a metabolic mechanism of radioadaptive response. The study supports a need for determining the p53 and HIF1α activity as a potential reliable biological readout of radiation exposure in humans. The exquisite sensitivity of cellular metabolism to low doses of radiation could also serve as a valuable biomarker for estimating the health effects of low-level radiation exposure.« less

Effect of active-region “volume” on the radiative properties of laser heterostructures with radiation output through the substrate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nekorkin, S. M.; Zvonkov, B. N.; Baidus, N. V.

2017-01-15

The radiative properties of InGaAs/GaAs/InGaP laser structures with radiation output through the substrate depending on the number of quantum wells in the active region and laser diodes on their basis are investigated. It is established that the presence of six–eight quantum wells in the active region is optimum from the viewpoint of observable values of the threshold current and the output optical power of lasers.

Radiation environment study of near space in China area

NASA Astrophysics Data System (ADS)

Fan, Dongdong; Chen, Xingfeng; Li, Zhengqiang; Mei, Xiaodong

2015-10-01

Aerospace activity becomes research hotspot for worldwide aviation big countries. Solar radiation study is the prerequisite for aerospace activity to carry out, but lack of observation in near space layer becomes the barrier. Based on reanalysis data, input key parameters are determined and simulation experiments are tried separately to simulate downward solar radiation and ultraviolet radiation transfer process of near space in China area. Results show that atmospheric influence on the solar radiation and ultraviolet radiation transfer process has regional characteristic. As key factors such as ozone are affected by atmospheric action both on its density, horizontal and vertical distribution, meteorological data of stratosphere needs to been considered and near space in China area is divided by its activity feature. Simulated results show that solar and ultraviolet radiation is time, latitude and ozone density-variant and has complicated variation characteristics.

Activation of eNOS in endothelial cells exposed to ionizing radiation involves components of the DNA damage response pathway

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nagane, Masaki; Yasui, Hironobu; Sakai, Yuri

2015-01-02

Highlights: • eNOS activity is increased in BAECs exposed to X-rays. • ATM is involved in this increased eNOS activity. • HSP90 modulates the radiation-induced activation of ATM and eNOS. - Abstract: In this study, the involvement of ataxia telangiectasia mutated (ATM) kinase and heat shock protein 90 (HSP90) in endothelial nitric oxide synthase (eNOS) activation was investigated in X-irradiated bovine aortic endothelial cells. The activity of nitric oxide synthase (NOS) and the phosphorylation of serine 1179 of eNOS (eNOS-Ser1179) were significantly increased in irradiated cells. The radiation-induced increases in NOS activity and eNOS-Ser1179 phosphorylation levels were significantly reduced bymore » treatment with either an ATM inhibitor (Ku-60019) or an HSP90 inhibitor (geldanamycin). Geldanamycin was furthermore found to suppress the radiation-induced phosphorylation of ATM-Ser1181. Our results indicate that the radiation-induced eNOS activation in bovine aortic endothelial cells is regulated by ATM and HSP90.« less

Ventilation duct with concurrent acoustic feed-forward and decentralised structural feedback active control

NASA Astrophysics Data System (ADS)

Rohlfing, J.; Gardonio, P.

2014-02-01

This paper presents theoretical and experimental work on concurrent active noise and vibration control for a ventilation duct. The active noise control system is used to reduce the air-borne noise radiated via the duct outlet whereas the active vibration control system is used to both reduce the structure-borne noise radiated by the duct wall and to minimise the structural feed-through effect that reduces the effectiveness of the active noise control system. An elemental model based on structural mobility functions and acoustic impedance functions has been developed to investigate the principal effects and limitations of feed-forward active noise control and decentralised velocity feedback vibration control. The principal simulation results have been contrasted and validated with measurements taken on a laboratory duct set-up, equipped with an active noise control system and a decentralised vibration control system. Both simulations and experimental results show that the air-borne noise radiated from the duct outlet can be significantly attenuated using the feed-forward active noise control. In the presence of structure-borne noise the performance of the active noise control system is impaired by a structure-borne feed-through effect. Also the sound radiation from the duct wall is increased. In this case, if the active noise control is combined with a concurrent active vibration control system, the sound radiation by the duct outlet is further reduced and the sound radiation from the duct wall at low frequencies reduces noticeably.

Comparative transcriptome analysis of rice seedlings induced by different doses of heavy ion radiation

NASA Astrophysics Data System (ADS)

Zhao, Qian; Sun, Yeqing; Wang, Wei

2016-07-01

Highly ionizing radiation (HZE) in space is considered as a main factor causing biological effects on plant seeds. To investigate the different effects on genome-wide gene expression of low-dose and high-dose ion radiation, we carried out ground-base carbon particle HZE experiments with different cumulative doses (0Gy, 0.2Gy, 2Gy) to rice seeds and then performed comparative transcriptome analysis of the rice seedlings. We identified a total of 2551 and 1464 differentially expressed genes (DEGs) in low-dose and high-dose radiation groups, respectively. Gene ontology analyses indicated that low-dose and high-dose ion radiation both led to multiple physiological and biochemical activities changes in rice. By Gene Ontology analyses, the results showed that only one process-oxidation reduction process was enriched in the biological process category after high-dose ion radiation, while more processes such as response to biotic stimulus, heme binding, tetrapyrrole binding, oxidoreductase activity, catalytic activity and oxidoreductase activity were significantly enriched after low-dose ion radiation. The results indicated that the rice plants only focused on the process of oxidation reduction to response to high-dose ion radiation, whereas it was a coordination of multiple biological processes to response to low-dose ion radiation. To elucidate the transcriptional regulation of radiation stress-responsive genes, we identified several DEGs-encoding TFs. AP2/EREBP, bHLH, C2H2, MYB and WRKY TF families were altered significantly in response to ion radiation. Mapman analysis speculated that the biological effects on rice seedlings caused by the radiation stress might share similar mechanisms with the biotic stress. Our findings highlight important alterations in the expression of radiation response genes, metabolic pathways, and TF-encoding genes in rice seedlings exposed to low-dose and high-dose ion radiation.

NEON Data Products: Supporting the Validation of GCOS Essential Climate Variables

NASA Astrophysics Data System (ADS)

Petroy, S. B.; Fox, A. M.; Metzger, S.; Thorpe, A.; Meier, C. L.

2014-12-01

The National Ecological Observatory Network (NEON) is a continental-scale ecological observation platform designed to collect and disseminate data that contributes to understanding and forecasting the impacts of climate change, land use change, and invasive species on ecology. NEON will collect in-situ and airborne data over 60 sites across the US, including Alaska, Hawaii, and Puerto Rico. The NEON Biomass, Productivity, and Biogeochemistry protocols currently direct the collection of samples from distributed, gradient, and tower plots at each site, with sampling occurring either multiple times during the growing season, annually, or on three- or five-year centers (e.g. for coarse woody debris). These data are processed into a series of field-derived data products (e.g. Biogeochemistry, LAI, above ground Biomass, etc.), and when combined with the NEON airborne hyperspectral and LiDAR imagery, are used support validation efforts of algorithms for deriving vegetation characteristics from the airborne data. Sites are further characterized using airborne data combined with in-situ tower measurements, to create additional data products of interest to the GCOS community, such as Albedo and fPAR. Presented here are a summary of tower/field/airborne sampling and observation protocols and examples of provisional datasets collected at NEON sites that may be used to support the ongoing validation of GCOS Essential Climate Variables.

A micromachined thermally compensated thin film Lamb wave resonator for frequency control and sensing applications

NASA Astrophysics Data System (ADS)

Wingqvist, G.; Arapan, L.; Yantchev, V.; Katardjiev, I.

2009-03-01

Micromachined thin film plate acoustic wave resonators (FPARs) utilizing the lowest order symmetric Lamb wave (S0) propagating in highly textured 2 µm thick aluminium nitride (AlN) membranes have been successfully demonstrated (Yantchev and Katardjiev 2007 IEEE Trans. Ultrason. Ferroelectr. Freq. Control 54 87-95). The proposed devices have a SAW-based design and exhibit Q factors of up to 3000 at a frequency around 900 MHz as well as design flexibility with respect to the required motional resistance. However, a notable drawback of the proposed devices is the non-zero temperature coefficient of frequency (TCF) which lies in the range -20 ppm K-1 to -25 ppm K-1. Thus, despite the promising features demonstrated, further device optimization is required. In this work temperature compensation of thin AlN film Lamb wave resonators is studied and experimentally demonstrated. Temperature compensation while retaining at the same time the device electromechanical coupling is experimentally demonstrated. The zero TCF Lamb wave resonators are fabricated onto composite AlN/SiO2 membranes. Q factors of around 1400 have been measured at a frequency of around 755 MHz. Finally, the impact of technological issues on the device performance is discussed in view of improving the device performance.

The mechanisms of protection of antioxidants on Nostoc sphaeroides against UV-B radiation

NASA Astrophysics Data System (ADS)

Wang, G. H.

UV radiation is one of space harmful factor for earth organisms in space exploration In the present work we studied on the role of antioxidant system in Nostoc sphaeroides K u tz Cyanobacteria and the effects of exogenous antioxidant molecules on its photosynthetic rate under UV-B radiation It was found that UV-B radiation decreased the photosynthetic activity of cyanobacterium but promoted the activity of antioxidant system to protect photosystem II PSII and exogenous antioxidant sodium nitroprusside SNP N-acetylcysteine NAC had an obvious protection on PSII activity under UV-B radiation The activity of SOD Superoxide Dismutase EC 1 15 1 1 CAT Catalase EC 1 11 1 6 POD Peroxidase EC 1 11 1 7 and content of MDA and ASC were improved by 0 5mM and 1mM SNP but 0 1mM SNP decreased the activity of antioxide system Exogenous NAC addition decreased the activity of SOD POD CAT and the content MDA and ASC but exogenous NAC addition increased the content of GSH The results suggested that exogenous SNP and NAC may protect algae by different mechanisms in which SNP maybe play double roles as sources of reactive free radicals or ROS scavengers in formation of algae s protection of PSII under UV-B radiation while NAC does function as antioxidant reagent or precursor of glutathione which could protect PSII directly from UV-B radiation Keyword antioxidant system exogenous or endogenous antioxidant Nostoc sphaeroides photosynthesis UV-B radiation

IN VITRO EFFECTS OF X-RADIATION ON WHITE BLOOD CELLS AND BLOOD PLATELETS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wagner, R.; Meyerriecks, N.; Berman, C.Z.

Alkaline phosphatase activity of leukocytes is enhanced by radiation with 50000 r. This disturbance accentuates the inherent aging process of white blood cells and may be explained by changes in the cell envelope. X radiation dimin ishes the endogenous oxygen uptake of leukocyte-platelet suspensions by approximately 20%. This response to radiation is demonstrable at exposures of as little as 5000 r. The decreasing effect is dimirished when substrates such as sodium succinate or alpha -glycerophosphate are added, within a wide range of their concentration. With increasing substrate concentration the decrease due to radiation approaches that of the endogenous respiration andmore » even exceeds it in some of the experiments. In pure blood platelets a similar decreasing x radiation effect occurs for endogenous respiration as well as succinic dehydrogenase activity; alpha -glycerophosphate dehydrogenase activity, on the other hand is enhanced. The oxygen uptake in leukocyteplatelet suspensions due only to leukocytes can be calculated. While the percentage radiation decrease of pure leukocytes is unchanged for endogenous and succirate activity, the decrease for alpha -glycerophosphate as substrate reaches considerably higher levels (68% compared with 8.2% in leukocyte-platelet suspensions). Thus alpha glycerophosphate dehydrogenase activity seems to be most sensitive to x radiation. It was shown in a previous study that alpha -glycerophosphate dehydrogenase is one of the most importart respiratory enzymes in leukocytes. The glycolytic system in leukocytes remains intact following exposure to radiation with 50000 r. (auth)« less

Frequency Tunable Wire Lasers

NASA Technical Reports Server (NTRS)

Hu, Qing (Inventor)

2013-01-01

The present invention provides frequency tunable solid-state radiation-generating devices, such as lasers and amplifiers, whose active medium has a size in at least one transverse dimension (e.g., its width) that is much smaller than the wavelength of radiation generated and/or amplified within the active medium. In such devices, a fraction of radiation travels as an evanescent propagating mode outside the active medium. It has been discovered that in such devices the radiation frequency can be tuned by the interaction of a tuning mechanism with the propagating evanescent mode.

p53 activated by AND gate genetic circuit under radiation and hypoxia for targeted cancer gene therapy

PubMed Central

Ding, Miao; Li, Rong; He, Rong; Wang, Xingyong; Yi, Qijian; Wang, Weidong

2015-01-01

Radio-activated gene therapy has been developed as a novel therapeutic strategy against cancer; however, expression of therapeutic gene in peritumoral tissues will result in unacceptable toxicity to normal cells. To restrict gene expression in targeted tumor mass, we used hypoxia and radiation tolerance features of tumor cells to develop a synthetic AND gate genetic circuit through connecting radiation sensitivity promoter cArG6, heat shock response elements SNF1, HSF1 and HSE4 with retroviral vector plxsn. Their construction and dynamic activity process were identified through downstream enhanced green fluorescent protein and wtp53 expression in non-small cell lung cancer A549 cells and in a nude mice model. The result showed that AND gate genetic circuit could be activated by lower required radiation dose (6 Gy) and after activated, AND gate could induce significant apoptosis effects and growth inhibition of cancer cells in vitro and in vivo. The radiation- and hypoxia-activated AND gate genetic circuit, which could lead to more powerful target tumoricidal activity represented a promising strategy for both targeted and effective gene therapy of human lung adenocarcinoma and low dose activation character of the AND gate genetic circuit implied that this model could be further exploited to decrease side-effects of clinical radiation therapy. PMID:26177264

NCRP Program Area Committee 5: Environmental Radiation and Radioactive Waste Issues

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, S. Y.; Napier, Bruce

Program Area Committee 5 of the National Council on Radiation Protection and Measurements (NCRP) focuses its activities on environmental radiation and radioactive waste issues. Historically this Committee addressed emerging issues of the nation pertaining to radioactivity or radiation in the environment or radioactive waste issues due either to natural origins or to manmade activities. The Committee continues to identify such issues in the future.

Effects of Microwave Radiation on Neuronal Activity

DTIC Science & Technology

1991-10-01

salivary glands and human cultured cells to extremely low- frequency (ELF) EMF alters patterns of polypeptide synthesis (18,19). The effects displayed...at 16 Hz. Continuous exposure to radio- frequency radiation for 4 consecutive days led to the development of a cell number density gradient. The...RADIATION ON NEURONAL ACTIVITY SUMMARY The effects of radiofrequency radiation on rat hippocampal fetal neurons were examined. Carrier frequencies of 300 to

The relationship between MMPs and pH in whole saliva of radiated head and neck cancer patients.

PubMed

Vuotila, T; Ylikontiola, L; Sorsa, T; Luoto, H; Hanemaaijer, R; Salo, T; Tjäderhane, L

2002-07-01

Radiation therapy for head and neck tumour patients may lead to decreased salivary flow, oral mucosal lesions and increased caries experience. Salivary matrix metalloproteinases (MMPs) may participate in the pathogenesis of mucosal lesions and dentinal caries. The aims of this study were: (i) to assay the presence, molecular forms and proteolytic activity of MMP-8 (collagenase-2) and MMP-9 (gelatinase B) in the whole saliva of head and neck cancer patients having radiation therapy; (ii) to see whether salivary pH affects the activity of MMP-8 and MMP-9; and (iii) to find out the possible connection between MMP-8 and MMP-9 with the eruption of oral mucosal lesions during radiation therapy. The whole saliva samples of 39 head and neck cancer patients having radiation therapy were collected before, during and after radiation therapy, and saliva flow rate, pH, buffer capacity, Streptococcus mutans, Lactobacillus and Candida albicans were measured. Any oral mucosal lesions were examined during each visit. The levels of MMP-8 were measured by immunofluorometric assay (IFMA) and the presence of different MMP-8 forms was analysed using Western immunoblotting. The presence and molecular forms of MMP-9 were analyzed by gelatin zymography. MMP-9 capture activity assay was used to determine the APMA-activated MMP-9 activity (total) and the endogenously active MMP-9 (free activity). Salivary flow rate, buffer capacity and pH decreased, and the levels of Lactobacilli increased significantly, during the first half of the radiation therapy. The endogenously activated salivary MMP-9 correlated with low salivary pH (P = 0.013). No connection was found between the oral mucosal lesions and salivary MMP-8 or MMP-9. In this study, salivary MMP-8 or MMP-9 did not correlate with the presence of radiation induced oral mucosal lesions, but the activation of MMP-9 may be dependent on pH.

From Assumption of Knowledge to Knowledgeable Considerations: a Class Activity on 'Ionizing Radiation' and Its Biological Effects.

ERIC Educational Resources Information Center

Ronen, Miky; Ganiel, Uri

1988-01-01

Describes a class activity, a game called "Beware--Radiation," developed as a framework for the introduction of the topic of radiation. Reports that both students and teachers had similar and mostly wrong preconceptions. (Author/YP)

Andrographolide Sensitizes Ras-Transformed Cells to Radiation in vitro and in vivo

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hung, Shih-Kai; Department of Radiation Oncology, Buddhist Dalin Tzu Chi General Hospital, Chiayi, Taiwan; Tzu Chi University School of Medicine, Hualian, Taiwan

2010-07-15

Purpose: Increasing the sensitivity of tumor cells to radiation is a major goal of radiotherapy. The present study investigated the radiosensitizing effects of andrographolide and examined the molecular mechanisms of andrographolide-mediated radiosensitization. Methods and Materials: An H-ras-transformed rat kidney epithelial (RK3E) cell line was used to measure the radiosensitizing effects of andrographolide in clonogenic assays, 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H tetrazolium bromide assays, and a xenograft tumor growth model. The mechanism of andrographolide-sensitized cell death was analyzed using annexin V staining, caspase 3 activity assays, and terminal transferase uridyl nick end labeling assays. The roles of nuclear factor kappa B (NF-{kappa}B) and Akt inmore » andrographolide-mediated sensitization were examined using reporter assays, electrophoretic mobility shift assays, and Western blotting. Results: Concurrent andrographolide treatment (10 {mu}M, 3 h) sensitized Ras-transformed cells to radiation in vitro (sensitizer enhancement ratio, 1.73). Andrographolide plus radiation (one dose of 300 mg/kg peritumor andrographolide and one dose of 6 Gy radiation) resulted in significant tumor growth delay (27 {+-} 2.5 days) compared with radiation alone (22 {+-} 1.5 days; p <.05). Radiation induced apoptotic markers (e.g., caspase-3, membrane reversion, DNA fragmentation), and andrographolide treatment did not promote radiation-induced apoptosis. However, the protein level of activated Akt was significantly reduced by andrographolide. NF-{kappa}B activity was elevated in irradiated Ras-transformed cells, and andrographolide treatment significantly reduced radiation-induced NF-{kappa}B activity. Conclusion: Andrographolide sensitized Ras-transformed cells to radiation both in vitro and in vivo. Andrographolide-mediated radiosensitization was associated with downregulation of Akt and NF-{kappa}B activity. These observations indicate that andrographolide is a novel radiosensitizing agent with potential application in cancer radiotherapy.« less

The influence of super-high-frequency radiation on the enzyme activity and number of microorganisms in soils of southern Russia

NASA Astrophysics Data System (ADS)

Denisova, T. V.; Kolesnikov, S. I.

2009-04-01

The effects of super-high-frequency radiation (SHF radiation) on the microflora and enzymatic activity of an ordinary chernozem, a chestnut soil, a brown forest soil, and gray sands were studied. The exposure time of the 800-W SHF radiation was 30 s, 1, 10, and 60 min. The activity of the soil enzymes (catalase and invertase) was found to be more resistant to the action of SHF radiation than the number of microorganisms (ammonifying bacteria (including sporogenous ones), bacteria of the genus Azotobacter, and micromycetes). According to the resistance of the enzymes, the soils studied form the following sequence: gray sands > ordinary chernozem ≥ chestnut soil > brown forest soil. Under the action of the SHF radiation, the number of microorganisms in the ordinary chernozem decreased to a lesser extent.

The biobehavioral and neuroimmune impact of low-dose ionizing radiation.

PubMed

York, Jason M; Blevins, Neil A; Meling, Daryl D; Peterlin, Molly B; Gridley, Daila S; Cengel, Keith A; Freund, Gregory G

2012-02-01

In the clinical setting, repeated exposures (10-30) to low-doses of ionizing radiation (≤200 cGy), as seen in radiotherapy for cancer, causes fatigue. Almost nothing is known, however, about the fatigue inducing effects of a single exposure to environmental low-dose ionizing radiation that might occur during high-altitude commercial air flight, a nuclear reactor accident or a solar particle event (SPE). To investigate the short-term impact of low-dose ionizing radiation on mouse biobehaviors and neuroimmunity, male CD-1 mice were whole body irradiated with 50 cGy or 200 cGy of gamma or proton radiation. Gamma radiation was found to reduce spontaneous locomotor activity by 35% and 36%, respectively, 6 h post irradiation. In contrast, the motivated behavior of social exploration was un-impacted by gamma radiation. Examination of pro-inflammatory cytokine gene transcripts in the brain demonstrated that gamma radiation increased hippocampal TNF-α expression as early as 4 h post-irradiation. This was coupled to subsequent increases in IL-1RA (8 and 12 h post irradiation) in the cortex and hippocampus and reductions in activity-regulated cytoskeleton-associated protein (Arc) (24 h post irradiation) in the cortex. Finally, restraint stress was a significant modulator of the neuroimmune response to radiation blocking the ability of 200 cGy gamma radiation from impairing locomotor activity and altering the brain-based inflammatory response to irradiation. Taken together, these findings indicate that low-dose ionizing radiation rapidly activates the neuroimmune system potentially causing early onset fatigue-like symptoms in mice. Copyright © 2011 Elsevier Inc. All rights reserved.

The biobehavioral and neuroimmune impact of low-dose ionizing radiation

PubMed Central

York, Jason M; Blevins, Neil A; Meling, Daryl D; Peterlin, Molly B; Gridley, Daila S; Cengel, Keith A; Freund, Gregory G

2011-01-01

In the clinical setting, repeated exposures (10–30) to low-doses of ionizing radiation (≤ 200 cGy), as seen in radiotherapy for cancer, causes fatigue. Almost nothing is known, however, about the fatigue inducing effects of a single exposure to environmental low-dose ionizing radiation that might occur during high-altitude commercial air flight, a nuclear reactor accident or a solar particle event (SPE). To investigate the short-term impact of low-dose ionizing radiation on mouse biobehaviors and neuroimmunity, male CD-1 mice were whole body irradiated with 50 cGy or 200 cGy of gamma or proton radiation. Gamma radiation was found to reduce spontaneous locomotor activity by 35% and 36%, respectively, 6 h post irradiation. In contrast, the motivated behavior of social exploration was un-impacted by gamma radiation. Examination of pro-inflammatory cytokine gene transcripts in the brain demonstrated that gamma radiation increased hippocampal TNF-α expression as early as 4 h post-irradiation. This was coupled to subsequent increases in IL-1RA (8 h and 12 h post irradiation) in the cortex and hippocampus and reductions in activity-regulated cytoskeleton-associated protein (Arc) (24 h post irradiation) in the cortex. Finally, restraint stress was a significant modulator of the neuroimmune response to radiation blocking the ability of 200 cGy gamma radiation from impairing locomotor activity and altering the brain-based inflammatory response to irradiation. Taken together, these findings indicate that low-dose ionizing radiation rapidly activates the neuroimmune system potentially causing early onset fatigue-like symptoms in mice. PMID:21958477

Radiation Measured with Different Dosimeters for ISS-Expedition 18-19/ULF2 on Board International Space Station during Solar Minimum

NASA Technical Reports Server (NTRS)

Zhou, Dazhuang; Gaza, R.; Roed, Y.; Semones, E.; Lee, K.; Steenburgh, R.; Johnson, S.; Flanders, J.; Zapp, N.

2010-01-01

Radiation field of particles in low Earth orbit (LEO) is mainly composed of galactic cosmic rays (GCR), solar energetic particles and particles in SAA (South Atlantic Anomaly). GCR are modulated by solar activity, at the period of solar minimum activity, GCR intensity is at maximum and the main contributor for space radiation is GCR. At present for space radiation measurements conducted by JSC (Johnson Space Center) SRAG (Space Radiation Analysis Group), the preferred active dosimeter sensitive to all LET (Linear Energy Transfer) is the tissue equivalent proportional counter (TEPC); the preferred passive dosimeters are thermoluminescence dosimeters (TLDs) and optically stimulated luminescence dosimeters (OSLDs) sensitive to low LET as well as CR-39 plastic nuclear track detectors (PNTDs) sensitive to high LET. For the method using passive dosimeters, radiation quantities for all LET can be obtained by combining radiation results measured with TLDs/OSLDs and CR-39 PNTDs. TEPC, TLDs/OSLDs and CR-39 detectors were used to measure the radiation field for the ISS (International Space Station) - Expedition 18-19/ULF2 space mission which was conducted from 15 November 2008 to 31 July 2009 - near the period of the recent solar minimum activity. LET spectra (differential and integral fluence, absorbed dose and dose equivalent) and radiation quantities were measured for positions TEPC, TESS (Temporary Sleeping Station, inside the polyethylene lined sleep station), SM-P 327 and 442 (Service Module - Panel 327 and 442). This paper presents radiation LET spectra measured with TEPC and CR-39 PNTDs and radiation dose measured with TLDs/OSLDs as well as the radiation quantities combined from results measured with passive dosimeters.

Carcinogen-Induced Microenvironment in Breast Cancer

DTIC Science & Technology

2000-04-01

unknown, the ability of radiation to induce TGF-P3 activation may gens , such as ionizing radiation, is to modify paracrine interactions indeed play a...radiation of the basement membrane proteins laminin and colla- induced proteases. In particular, tissue-type plasmino- gen IV were unchanged during the week...following gen activator is induced in a variety of irradiated cells radiation, marked changes in the periepithelial and and tissues (33) while plasmin

THE EFFECTS OF ULTRAVIOLET LIGHT AND GAMMA RAYS ON CELL LIPIDS AND THE PHYSIOLOGICAL ACTION OF IRRADIATED LIPIDS. Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bernheim, F.; Wilbur, K.M.

1962-03-26

Results are summarized from a series of studies on the effects of ultraviolet and ionizing radiation on the oxidation of cell lipids. It was shown that both in vitro and in vivo radiation produced oxidation products of lipids that inhibited the activity of certain oxidative enzymes, depolymerized desoxyribonucleoprotein, inhibited the division of marine eggs, and retarded bacterial growth. The presence of antioxidant activity was also demonstrated in tissues. The significant feature of antioxidant compounds with respect to the biological effects of radiation was shown to be the inhibition of the oxidation of lipids. In irradiated animals the antioxidant activity ofmore » the intestinal mucosa and the activity of phospholipase decreased. Experiments showed that radiation had not destroyed the enzyme but had inactivated the activator. Results are also summarized from a study on the effects of ionizing radiation on cell growth and protein synthesis in yeast. (C.H.)« less

The role of obesity and physical activity in non-specific and radiating low back pain: the Young Finns study.

PubMed

Shiri, Rahman; Solovieva, Svetlana; Husgafvel-Pursiainen, Kirsti; Telama, Risto; Yang, Xiaolin; Viikari, Jorma; Raitakari, Olli T; Viikari-Juntura, Eira

2013-06-01

To study the effects of obesity, physical activity, and change in physical activity on the incidence of low back pain and explore whether obesity modifies the effects of physical activity. As part of the ongoing Young Finns Study, 1224 subjects aged 24-39 years free from low back pain during the preceding 12 months at baseline in 2001 were included. Obesity was defined based on the body mass index (BMI) and waist circumference, and physical activity was assessed by the metabolic equivalent of task (MET) index in 2001 and 2007. Abdominal obesity, defined by an increased waist circumference, was associated with an increased incidence of radiating low back pain (adjusted odds ratio (OR) = 1.7 and 95% confidence interval (CI) 1.1-2.7), while it had no effect on non-specific low back pain. BMI was associated neither with the incidence of radiating low back pain nor with non-specific low back pain. Compared with subjects who stayed active during follow-up, those with a low level of physical activity (adjusted OR = 2.0 and 95% CI 1.1-3.5) and active subjects who further increased their physical activity during follow-up (OR = 3.1 and 95% CI 1.5-6.7) had a higher incidence of radiating low back pain. Low level of physical activity was associated with an increased incidence of radiating low back pain in obese (OR = 3.3 and 95% 1.1-10.4), but not in non-overweight subjects (OR = 1.1 and 95% CI 0.6-1.9). Physical activity was not associated with non-specific low back pain. Our findings indicate that both obesity and low level of physical activity are independent risk factors of radiating low back pain. The current findings propose a U-shaped relation between physical activity and radiating low back pain. Moderate level of physical activity is recommended for the prevention of low back pain, especially in obese individuals. In all, our findings imply that obese individuals should stay physically active, even if they may not lose weight. Copyright © 2013 Elsevier Inc. All rights reserved.

[The opportunity to use combined stem cells transplantation for haemopoesis activation in the old and mature laboratory animals under the conditions of ionizing radiation].

PubMed

Grebnev, D Iu; Maklakova, I Iu; Iastrebov, A P

2014-01-01

The objective of this work was to study the influence of combined transplantation of stem cells (multypotent mesenchimal stromal and haemopoetic stem cells) on the haemopoesis of old and mature laboratory animals under the condition of ionizing radiation. The result of the experiment shows that under physiological conditions the combined transplantation brings the erithropoesis activation, under the ionizing radiation conditions it brings the erythroid and granulocytopoesis activation. Moreover the combined MMSC and HSC transplantation gives cytoprotective action on the myeloid tissue due to decrease of cyto genically changed cells in the mature animals under the condition of ionizing radiation, but in the old animals this effect can be seen even under physiological condition. Combined transplantation of MMSC and GSC can be used in the mature and old laboratory animals under the conditions of ionising radiation for the haemopoesis activation.

Acquired Tumor Cell Radiation Resistance at the Treatment Site Is Mediated Through Radiation-Orchestrated Intercellular Communication

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aravindan, Natarajan, E-mail: naravind@ouhsc.edu; Aravindan, Sheeja; Pandian, Vijayabaskar

2014-03-01

Purpose: Radiation resistance induced in cancer cells that survive after radiation therapy (RT) could be associated with increased radiation protection, limiting the therapeutic benefit of radiation. Herein we investigated the sequential mechanistic molecular orchestration involved in radiation-induced radiation protection in tumor cells. Results: Radiation, both in the low-dose irradiation (LDIR) range (10, 50, or 100 cGy) or at a higher, challenge dose IR (CDIR), 4 Gy, induced dose-dependent and sustained NFκB-DNA binding activity. However, a robust and consistent increase was seen in CDIR-induced NFκB activity, decreased DNA fragmentation, apoptosis, and cytotoxicity and attenuation of CDIR-inhibited clonal expansion when the cellsmore » were primed with LDIR prior to challenge dose. Furthermore, NFκB manipulation studies with small interfering RNA (siRNA) silencing or p50/p65 overexpression unveiled the influence of LDIR-activated NFκB in regulating CDIR-induced DNA fragmentation and apoptosis. LDIR significantly increased the transactivation/translation of the radiation-responsive factors tumor necrosis factor-α (TNF-α), interleukin-1α (IL-1α), cMYC, and SOD2. Coculture experiments exhibit LDIR-influenced radiation protection and increases in cellular expression, secretion, and activation of radiation-responsive molecules in bystander cells. Individual gene-silencing approach with siRNAs coupled with coculture studies showed the influence of LDIR-modulated TNF-α, IL-1α, cMYC, and SOD2 in induced radiation protection in bystander cells. NFκB inhibition/overexpression studies coupled with coculture experiments demonstrated that TNF-α, IL-1α, cMYC, and SOD2 are selectively regulated by LDIR-induced NFκB. Conclusions: Together, these data strongly suggest that scattered LDIR-induced NFκB-dependent TNF-α, IL-1α, cMYC, and SOD2 mediate radiation protection to the subsequent challenge dose in tumor cells.« less

Effects of UVB radiation on Photosynthesis Activity of Wolffia arrhiza as Probed by Chlorophyll Fluorescence Transient

NASA Astrophysics Data System (ADS)

Wang, Gaohong; Hao, Zongjie; Chen, Kun; Liu, Yongding

UV radiation is one major environmental stress for growth of Wolffia arrhiza which is regarded as a good candidate producer for establishing CELSS during extraterrestrial colonization and spaceflight. In this study, we found that UVB radiation inhibited photosynthetic CO2 assimilation activity significantly, and the content of chlorophyll a, chlorophyll b and carotenoids decreased obviously when plants were exposed to UVB radiation for 6 h. High UVB radiation also declined the quantum yield of primary photochemistry (φPo), the quantum yield for electron transport (φEo) and the efficiency per trapped excitation (ψo) in the cells of Wolffia arrhiza simultaneously, while the amount of active PSII reaction centers per excited cross section (RC/CS) and the total number of active reaction center per absorption (RC/ABS) had the same changes under UV-B radiation stress. These results indicated that the effects of UV- B radiation on photosynthesis of Wolffia arrhiza maybe functioned by inhibition the electron transport and inactivation of reaction centers, but the inhibition maybe happen in more than one site in photosynthetic apparatus which is different to that in salt adaptation.

A dynamic analysis of the radiation excitation from the activation of a current collecting system in space

NASA Technical Reports Server (NTRS)

Wang, J.; Hastings, D. E.

1991-01-01

Current collecting systems moving in the ionosphere will induce electromagnetic wave radiation. The commonly used static analysis is incapable of studying the situation when such systems undergo transient processes. A dynamic analysis has been developed, and the radiation excitation processes are studied. This dynamic analysis is applied to study the temporal wave radiation from the activation of current collecting systems in space. The global scale electrodynamic interactions between a space-station-like structure and the ionospheric plasma are studied. The temporal evolution and spatial propagation of the electric wave field after the activation are described. The wave excitations by tethered systems are also studied. The dependencies of the temporal Alfven wave and lower hybrid wave radiation on the activation time and the space system structure are discussed. It is shown that the characteristics of wave radiation are determined by the matching of two sets of characteristic frequencies, and a rapid change in the current collection can give rise to substantial transient radiation interference. The limitations of the static and linear analysis are examined, and the condition under which the static assumption is valid is obtained.

Samarium-145 and its use as a radiation source

DOEpatents

Fairchild, Ralph G.; Laster, Brenda H.; Packer, Samuel

1989-09-05

The present invention covers a new radiation source, samarium-145, with radiation energies slightly above those of I-125 and a half-life of 340 days. The samarium-145 source is produced by neutron irradiation of SM-144. This new source is useful as the implanted radiation source in photon activation therapy of malignant tumors to activate the stable I-127 contained in the IdUrd accumulated in the tumor, causing radiation sensitization and Auger cascades that irreperably damage the tumor cells. This new source is also useful as a brachytherapy source.

Samarium-145 and its use as a radiation source

DOEpatents

Fairchild, Ralph G.; Laster, Brenda H.; Packer, Samuel

1989-01-01

The present invention covers a new radiation source, samarium-145, with radiation energies slightly above those of I-125 and a half-life of 340 days. The samarium-145 source is produced by neutron irradiation of SM-144. This new source is useful as the implanted radiation source in photon activation therapy of malignant tumors to activate the stable I-127 contained in the IdUrd accumulated in the tumor, causing radiation sensitization and Auger cascades that irreperably damage the tumor cells. This new source is also useful as a brachytherapy source.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ward, W.F.; Molteni, A.; Ts'ao, C.H.

The purpose of this study was to evaluate the angiotensin converting enzyme (ACE) inhibitor CL242817 as a modifier of radiation-induced pulmonary endothelial dysfunction and pulmonary fibrosis in rats sacrificed 2 months after a single dose of 60Co gamma rays (0-30 Gy) to the right hemithorax. CL242817 was administered in the feed continuously after irradiation at a regimen of 60 mg/kg/day. Pulmonary endothelial function was monitored by lung ACE activity, plasminogen activator (PLA) activity, and prostacyclin (PGI2) and thromboxane (TXA2) production. Pulmonary fibrosis was evaluated by lung hydroxyproline (HP) content. Lung ACE and PLA activities decreased with increasing radiation dose, andmore » cotreatment with CL242817 significantly ameliorated both responses. CL242817 dose-reduction factors (DRF) were 1.3-1.5 for ACE and PLA activity. Lung PGI2 and TXA2 production increased with increasing radiation dose, and CL242817 almost completely prevented both radiation responses. The slope of the radiation dose-response curves in the CL242817-treated rats was essentially zero, precluding calculation of DRF values for PGI2 and TXA2 production. Lung HP content also increased with increasing radiation dose, and CL242817 significantly attenuated this response (DRF = 1.5). These data suggest that the ability of ACE inhibitors to ameliorate radiation-induced pulmonary endothelial dysfunction is not unique to captopril, rather it is a therapeutic action shared by other members of this class of compounds. These data also provide the first evidence that ACE inhibitors exhibit antifibrotic activity in irradiated rat lung.« less

Measures against increased environmental radiation dose by the TEPCO Fukushima Dai-ichi NPP accident in some local governments in the Tokyo metropolitan area: focusing on examples of both Kashiwa and Nagareyama cities in Chiba prefecture.

PubMed

Iimoto, T; Fujii, H; Oda, S; Nakamura, T; Hayashi, R; Kuroda, R; Furusawa, M; Umekage, T; Ohkubo, Y

2012-11-01

The accident of the Fukushima Dai-ichi nuclear power plant of Tokyo Electric Power Cooperation (TEPCO) after the great east Japan earthquake (11 March 2011) elevated the background level of environmental radiation in Eastern Japan. Around the Tokyo metropolitan area, especially around Kashiwa and Nagareyama cities, the ambient dose equivalent rate has been significantly increased after the accident. Responding to strong requests from citizens, the local governments started to monitor the ambient dose equivalent rate precisely and officially, about 3 months after the accident had occurred. The two cities in cooperation with each other also organised a local forum supported by three radiation specialists. In this article, the activities of the local governments are introduced, with main focus on radiation monitoring and measurements. Topics are standardisation of environmental radiation measurements for ambient dose rate, dose mapping activity, investigation of foodstuff and drinking water, lending survey meters to citizens, etc. Based on the data and facts mainly gained by radiation monitoring, risk management and relating activity have been organised. 'Small consultation meetings in kindergartens', 'health consultation service for citizens', 'education meeting on radiation protection for teachers, medical staffs, local government staffs, and leaders of active volunteer parties' and 'decontamination activity', etc. are present key activities of the risk management and restoration around the Tokyo metropolitan area.

Space activities and radiation protection of crew members

NASA Astrophysics Data System (ADS)

Straube, Ulrich; Berger, Thomas; Reitz, Guenther; Facius, Rainer; Reiter, Thomas; Kehl, Marcel; Damann, M. D. Volker; Tognini, Michel

Personnel working as crew in space-based activities e.g. professional astronauts and cosmo-nauts but also -to a certain extend-space flight participants ("space tourists"), demand health and safety considerations that have to include radiation protection measures. The radiation environment that a crew is exposed to during a space flight, differs significantly to that found on earth including commercial aviation, mainly due to the presence of heavy charged particles with great potential for biological damage. The exposure exceeds those routinely received by terrestrial radiation workers. A sequence of activities has to be conducted targeting to mitigate adverse effects of space radiation. Considerable information is available and applied through the joint efforts of the Space Agencies that are involved in the operations of the International Space Station, ISS. This presentation will give an introduction to the current measures for ra-diation monitoring and protection of astronauts of the European Space Agency (ESA). It will include information: on the radiation protection guidelines that shall ensure the proper imple-mentation and execution of radiation protection measures, the operational hardware used for radiation monitoring and personal dosimetry on ISS, as well as information about operational procedures that are applied.

p53 activated by AND gate genetic circuit under radiation and hypoxia for targeted cancer gene therapy.

PubMed

Ding, Miao; Li, Rong; He, Rong; Wang, Xingyong; Yi, Qijian; Wang, Weidong

2015-09-01

Radio-activated gene therapy has been developed as a novel therapeutic strategy against cancer; however, expression of therapeutic gene in peritumoral tissues will result in unacceptable toxicity to normal cells. To restrict gene expression in targeted tumor mass, we used hypoxia and radiation tolerance features of tumor cells to develop a synthetic AND gate genetic circuit through connecting radiation sensitivity promoter cArG6 , heat shock response elements SNF1, HSF1 and HSE4 with retroviral vector plxsn. Their construction and dynamic activity process were identified through downstream enhanced green fluorescent protein and wtp53 expression in non-small cell lung cancer A549 cells and in a nude mice model. The result showed that AND gate genetic circuit could be activated by lower required radiation dose (6 Gy) and after activated, AND gate could induce significant apoptosis effects and growth inhibition of cancer cells in vitro and in vivo. The radiation- and hypoxia-activated AND gate genetic circuit, which could lead to more powerful target tumoricidal activity represented a promising strategy for both targeted and effective gene therapy of human lung adenocarcinoma and low dose activation character of the AND gate genetic circuit implied that this model could be further exploited to decrease side-effects of clinical radiation therapy. © 2015 The Authors. Cancer Science published by Wiley Publishing Asia Pty Ltd on behalf of Japanese Cancer Association.

Radiation doses for pediatric nuclear medicine studies: comparing the North American consensus guidelines and the pediatric dosage card of the European Association of Nuclear Medicine.

PubMed

Grant, Frederick D; Gelfand, Michael J; Drubach, Laura A; Treves, S Ted; Fahey, Frederic H

2015-04-01

Estimated radiation dose is important for assessing and communicating the risks and benefits of pediatric nuclear medicine studies. Radiation dose depends on the radiopharmaceutical, the administered activity, and patient factors such as age and size. Most radiation dose estimates for pediatric nuclear medicine have not been based on administered activities of radiopharmaceuticals recommended by established practice guidelines. The dosage card of the European Association of Nuclear Medicine (EANM) and the North American consensus guidelines each provide recommendations of administered activities of radiopharmaceuticals in children, but there are substantial differences between these two guidelines. For 12 commonly performed pediatric nuclear medicine studies, two established pediatric radiopharmaceutical administration guidelines were used to calculate updated radiation dose estimates and to compare the radiation exposure resulting from the recommendations of each of the guidelines. Estimated radiation doses were calculated for 12 common procedures in pediatric nuclear medicine using administered activities recommended by the dosage card of the EANM (version 1.5.2008) and the 2010 North American consensus guidelines for radiopharmaceutical administered activities in pediatrics. Based on standard models and nominal age-based weights, radiation dose was estimated for typical patients at ages 1, 5, 10 and 15 years and adult. The resulting effective doses were compared, with differences greater than 20% considered significant. Following either the EANM dosage card or the 2010 North American guidelines, the highest effective doses occur with radiopharmaceuticals labeled with fluorine-18 and iodine-123. In 24% of cases, following the North American consensus guidelines would result in a substantially higher radiation dose. The guidelines of the EANM dosage card would lead to a substantially higher radiation dose in 39% of all cases, and in 62% of cases in which patients were age 5 years or younger. For 12 commonly performed pediatric nuclear medicine studies, updated radiation dose estimates can guide efforts to reduce radiation exposure and provide current information for discussing radiation exposure and risk with referring physicians, patients and families. There can be substantial differences in radiation exposure for the same procedure, depending upon which of these two guidelines is followed. This discordance identifies opportunities for harmonization of the guidelines, which may lead to further reduction in nuclear medicine radiation doses in children.

Radiation-induced inflammatory markers of brain injury are modulated by PPARdelta activation in vitro and in vivo

NASA Astrophysics Data System (ADS)

Schnegg, Caroline Isabel

As a result of improvements in cancer therapy and health care, the population of long-term cancer survivors is growing. For these approximately 12 million long-term cancer survivors, brain metastases are a significant risk. Fractionated partial or whole-brain irradiation (fWBI) is often required to treat both primary and metastatic brain cancer. Radiation-induced normal tissue injury, including progressive cognitive impairment, however, can significantly affect the well-being of the approximately 200,000 patients who receive these treatments each year. Recent reports indicate that radiation-induced brain injury is associated with chronic inflammatory and oxidative stress responses, as well as increased microglial activation in the brain. Anti-inflammatory drugs may, therefore, be a beneficial therapy to mitigate radiation-induced brain injury. We hypothesized that activation of peroxisomal proliferator activated receptor delta (PPARō) would prevent or ameliorate radiation-induced brain injury, including cognitive impairment, in part, by alleviating inflammatory responses in microglia. For our in vitro studies, we hypothesized that PPARō activation would prevent the radiation-induced inflammatory response in microglia following irradiation. Incubating BV-2 murine microglial cells with the (PPAR)ō agonist, L-165041, prevented the radiation-induced increase in: i) intracellular ROS generation, ii) Cox-2 and MCP-1 expression, and iii) IL-1β and TNF-α message levels. This occured, in part, through PPARō-mediated modulation of stress activated kinases and proinflammatory transcription factors. PPARō inhibited NF-κB via transrepression by physically interacting with the p65 subunit, and prevented activation of the PKCα/MEK1/2/ERK1/2/AP-1 pathway by inhibiting the radiation-induced increase in intracellular ROS generation. These data support the hypothesis that PPARō activation can modulate the radiation-induced oxidative stress and inflammatory responses in microglia in vitro. To extend our in vitro findings in vivo, we investigated whether administration of the peroxisomal proliferator-activated receptor (PPAR)ä agonist, GW0742, prevented radiation-induced brain injury in C57Bl/6 WT mice. Our data demonstrate that GW0742 prevented the radiation-induced increase in the number of activated microglia (CD68+ cells) in wild-type (WT) mice 1 week following 10 Gy WBI. Furthermore, GW0742 inhibited the WBI-induced increase in IL-1β message levels and ERK phosphorylation observed 3 h post-irradiation. In contrast, GW0742 administration failed to modulate the radiation-induced decrease in hippocampal neurogenesis (NeuN+/BrdU+ cells) determined 2 months after irradiation, or mitigate hippocampal-dependent spatial memory impairment observed 3 months post-irradiation using the Barnes Maze task. We used PPARō knockout (KO) mice to examine if the effects of GW0742 are PPARō-dependent. Unexpectedly, PPARō KO mice exhibited a differential response following WBI compared to WT mice; therefore, we were unable to make mechanistic conclusions about GW0742. KO mice do not exhibit a WBI-induced increase in activated microglia; however, they appeared to display a pronounced astrocytic response. In particular, PPARō KO but not WT mice displayed increased GFAP message levels 2 months after WBI. Additionally, the number of GFAP+ cells was reduced significantly in the WT mice 2 months after WBI, but it was not in the PPARō KO mice. These results demonstrate that: i) GW0742 prevents the radiation-induced increase in microglial activation and inflammatory markers, and ii) WT and PPARō KO mice have a differential response to WBI.

Degradation of Biochemical Activity in Soil Sterilized by Dry Heat and Gamma Radiation

NASA Technical Reports Server (NTRS)

Shih, K. L.; Souza, K. A.

1978-01-01

The effect of soil sterilization by dry heat (0.08% relative humidity), gamma radiation, or both on soil phosphatase, urease, and decarboxylase activity was studied. Soil sterilized by a long exposure to dry heat at relatively low temperatures (eight weeks at 100.5 C) retained higher activities than did soil exposed to a higher temperature (two weeks at 124.5 C), while all activity was destroyed by four days at 148.5 C. Sterilization with 7.5 Mrads destroyed less activity than did heat sterilization. The effect of several individually nonsterizing doses of heat radiation is described.

Gamma-radiation effects on luminescence properties of Eu3+ activated LaPO4 phosphor

NASA Astrophysics Data System (ADS)

Vujčić, Ivica; Gavrilović, Tamara; Sekulić, Milica; Mašić, Slobodan; Putić, Slaviša; Papan, Jelena; Dramićanin, Miroslav D.

2018-05-01

Eu3+ activated LaPO4 phosphors were prepared by a high-temperature solid-state method and irradiated to different high-doses gamma-radiation in the 0-4 MGy range. No effects of high-doses of high-energy radiation on phosphor's morphology and structure were observed, as documented by electron microscopy and X-ray diffraction measurements. On the other hand, photoluminescence measurements showed that emission properties of phosphor were affected by gamma-radiation; changes in radiative properties being prominent for absorbed radiation doses up to 250 kGy after which no additional changes are observed. Judd-Ofelt analysis of emission spectra is performed to thoroughly investigate radiative properties of phosphors. Analysis showed that radiative transition probability of Eu3+ emission decreases while non-radiative probability increases upon gamma-irradiation. Quantum efficiency of emission is decreased from about 46% to 35% when Eu3+ doped LaPO4 powders are exposed to gamma-radiation of 250 kGy dose, showing no additional decrease for higher gamma-radiation doses.

γ-Secretase inhibitor enhances antitumour effect of radiation in Notch-expressing lung cancer

PubMed Central

Mizugaki, H; Sakakibara-Konishi, J; Ikezawa, Y; Kikuchi, J; Kikuchi, E; Oizumi, S; Dang, T P; Nishimura, M

2012-01-01

Background: Notch receptor has an important role in both development and cancer. We previously reported that inhibition of the Notch3 by γ-secretase inhibitor (GSI) induces apoptosis and suppresses tumour proliferation in non-small-cell lung cancer. Although radiation is reported to induce Notch activation, little is known about the relationship between radiation and Notch pathway. Methods: We examined the effect of combining GSI and radiation at different dosing in three Notch expressing lung cancer cell lines. The cytotoxic effect of GSI and radiation was evaluated using MTT assay and clonogenic assay in vitro and xenograft models. Expressions of Notch pathway, mitogen-activated protein kinase (MAPK) pathway and Bcl-2 family proteins were investigated using western blot analysis. Results: We discovered that the antitumour effect of combining GSI and radiation was dependent on treatment schedule. γ-Secretase inhibitor administration after radiation had the greatest growth inhibition of lung cancer in vitro and in vivo. We showed that the combination induced apoptosis of lung cancer cell lines through the regulation of MAPK and Bcl-2 family proteins. Furthermore, activation of Notch after radiation was ameliorated by GSI administration, suggesting that treatment with GSI prevents Notch-induced radiation resistance. Conclusion: Notch has an important role in lung cancer. Treatment with GSI after radiation can significantly enhance radiation-mediated tumour cytotoxicity. PMID:22596234

Influence of UV radiation on chlorophyll, and antioxidant enzymes of wetland plants in different types of constructed wetland.

PubMed

Xu, Defu; Wu, Yinjuan; Li, Yingxue; Howard, Alan; Jiang, Xiaodong; Guan, Yidong; Gao, Yongxia

2014-09-01

A surface- and vertical subsurface-flow-constructed wetland were designed to study the response of chlorophyll and antioxidant enzymes to elevated UV radiation in three types of wetland plants (Canna indica, Phragmites austrail, and Typha augustifolia). Results showed that (1) chlorophyll content of C. indica, P. austrail, and T. augustifolia in the constructed wetland was significantly lower where UV radiation was increased by 10 and 20 % above ambient solar level than in treatment with ambient solar UV radiation (p < 0.05). (2) The malondialdehyde (MDA) content, guaiacol peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) activities of wetland plants increased with elevated UV radiation intensity. (3) The increased rate of MDA, SOD, POD, and CAT activities of C. indica, P. australis, and T. angustifolia by elevated UV radiation of 10 % was higher in vertical subsurface-flow-constructed wetland than in surface-flow-constructed wetland. The sensitivity of MDA, SOD, POD, and CAT activities of C. indica, P. austrail, and T. augustifolia to the elevated UV radiation was lower in surface-flow-constructed wetland than in the vertical subsurface-flow-constructed wetland, which was related to a reduction in UV radiation intensity through the dissolved organic carbon and suspended matter in the water. C. indica had the highest SOD and POD activities, which implied it is more sensitive to enhanced UV radiation. Therefore, different wetland plants had different antioxidant enzymes by elevated UV radiation, which were more sensitive in vertical subsurface-flow-constructed wetland than in surface-flow-constructed wetland.

WE-E-BRE-12: Tumor Microenvironment Dynamics Following Radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Campos, D; Niles, D; Adamson, E

2014-06-15

Purpose: This work aims to understand the radiation-induced interplay between tumor oxygenation and metabolic activity. These dynamics can potentially serve as biomarkers in assessing treatment response allowing for patient-specific adaptive radiotherapy. Methods: Using patient-derived xenografts of head and neck cancer we assessed tumor oxygenation via fiber-optic probe monitored hemoglobin saturation and Blood Oxygen Level Dependent (BOLD) MRI. Measurements were taken before and after a 10 Gy dose of radiation. Changes in metabolic activity were measured via Fluorescence Lifetime IMaging (FLIM) with the appropriate controls following a 10 Gy dose of radiation. FLIM can non-invasively monitor changes in fluorescence in responsemore » to the microenvironment including being able to detect free and bound states of the intrinsically fluorescent metabolite NADH (Nicotinamide Adenine Dinucleotide). With this information FLIM can accurately quantify the metabolic state of cells that have been radiated. To model the observed changes, a two-compartment, source-sink simulation relating hemoglobin saturation and metabolic activity was performed using MATLAB. Results: Hemoglobin saturation as measured by interstitial probe and BOLD-MRI decreased by 30% within 15 minutes following radiation. FLIM demonstrated a decrease in the mean fluorescence lifetime of NADH by 100 ps following 10 Gy indicating a shift towards glycolytic pathways. Simulation of radiation-induced alterations in tumor oxygenation demonstrated that these changes can be the result of changes in either vasculature or metabolic activity. Conclusion: Radiation induces significant changes in hemoglobin saturation and metabolic activity. These alterations occur on time scales approximately the duration of common radiation treatments. Further understanding these dynamics has important implications with regard to improvement of therapy and biomarkers of treatment response.« less

Radiation and Maxwell Stress Stabilization of Liquid Bridges

NASA Technical Reports Server (NTRS)

Marr-Lyon, M. J.; Thiessen, D. B.; Blonigen, F. J.; Marston, P. L.

1999-01-01

The use of both acoustic radiation stress and the Maxwell stress to stabilize liquid bridges is reported. Acoustic radiation stress arises from the time-averaged acoustic pressure at the surface of an object immersed in a sound field. Both passive and active acoustic stabilization schemes as well as an active electrostatic method are examined.

Evaluating the Radiation Damage to Quartz Rods in the ATLAS Zero Degree Calorimeter

NASA Astrophysics Data System (ADS)

Goodale, Kathryn

2017-09-01

At the Large Hadron Collider, the ATLAS experiment studies particle collisions to explore the fundamental particles of nature. A key instrumentation technology used by the ATLAS experiment are calorimeters for particle energy measurements. UIUC is developing a new Zero-Degree Calorimeter; a hadronic calorimeter located at zero-degrees from the collision axis. It consists of alternating layers of tungsten and oil; passive and active layers, respectively. The passive layers cause intense showers of secondary particles. These particles then produce Cherenkov radiation in the active layer. The oil in the active layer is replaced at a constant rate allowing for very high radiation doses in the detector without deteriorating the radiator material. The active layer includes wavelength shifters that absorb and re-emit isotropically the Cherenkov radiation. In this way, some of the photons arrive at two, hollow quartz rods which are filled by a second stage wavelength shifter. Here the light is absorbed and re-directed to a Silicon Photomultiplier for detection. In this paper, the impact of ionizing radiation on quartz rods will be discussed and the results from attenuation measurements will be presented.

Role of lymphocyte-specific protein tyrosine kinase (LCK) in the expansion of glioma-initiating cells by fractionated radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Rae-Kwon; Yoon, Chang-Hwan; Hyun, Kyung-Hwan

2010-11-26

Research highlights: {yields} Activation of Lymphocyte-specific protein tyrosine kinase (LCK) is involved in the fractionated radiation-induced expansion of glioma stem-like cells. {yields} Inhibition of LCK prevents acquisition of fractionated radiation-induced resistance to chemotherapeutic treatment. {yields} LCK activity is critical for the maintenance of self-renewal in glioma stem-like cells. -- Abstract: Brain cancers frequently recur or progress as focal masses after treatment with ionizing radiation. Radiation used to target gliomas may expand the cancer stem cell population and enhance the aggressiveness of tumors; however, the mechanisms underlying the expansion of cancer stem cell population after radiation have remained unclear. In thismore » study, we show that LCK (lymphocyte-specific protein tyrosine kinase) is involved in the fractionated radiation-induced expansion of the glioma-initiating cell population and acquisition of resistance to anticancer treatments. Fractionated radiation caused a selective increase in the activity of LCK, a Src family non-receptor tyrosine kinase. The activities of other Src family kinases Src, Fyn, and Lyn were not significantly increased. Moreover, knockdown of LCK expression with a specific small interfering RNA (siRNA) effectively blocked fractionated radiation-induced expansion of the CD133{sup +} cell population. siRNA targeting of LCK also suppressed fractionated radiation-induced expression of the glioma stem cell marker proteins CD133, Nestin, and Musashi. Expression of the known self-renewal-related proteins Notch2 and Sox2 in glioma cells treated with fractionated radiation was also downregulated by LCK inhibition. Moreover, siRNA-mediated knockdown of LCK effectively restored the sensitivity of glioma cells to cisplatin and etoposide. These results indicate that the non-receptor tyrosine kinase LCK is critically involved in fractionated radiation-induced expansion of the glioma-initiating cell population and decreased cellular sensitivity to anticancer treatments. These findings may provide pivotal insights in the context of fractionated radiation-based therapeutic interventions in brain cancer.« less

Enzymological mechanism for the regulation of lanthanum chloride on flavonoid synthesis of soybean seedlings under enhanced ultraviolet-B radiation.

PubMed

Fan, Caixia; Hu, Huiqing; Wang, Lihong; Zhou, Qing; Huang, Xiaohua

2014-01-01

In order to probe into the enzymological mechanism for the regulation of lanthanum chloride (LaCl3) on flavonoid synthesis in plants under enhanced ultraviolet-B (UV-B) radiation, the effects of LaCl₃ (20 and 60 mg l(-1)) on the content of flavonoids as well as the activities of phenylalanine ammonia-lyase (PAL), cinnamate-4-hydroxylase (C4H), 4-coumarate : coenzyme A ligase (4CL), and chalcone synthase (CHS) in soybean seedlings under enhanced UV-B radiation (2.6 and 6.2 kJ m(-2) day(-1)) were investigated. Enhanced UV-B radiation (2.6 and 6.2 kJ m(-2) day(-1)) caused the increase in the content of flavonoids as well as the activities of PAL, C4H, 4CL, and CHS in soybean seedlings. The treatment of 20 mg l(-1) LaCl₃ also efficiently increased these indices, which promoted the flavonoid synthesis and provided protective effects for resisting enhanced UV-B radiation. On the contrary, the treatment of 60 mg l(-1) LaCl₃ decreased the content of flavonoids as well as the activities of C4H, 4CL, and CHS in soybean seedlings except increasing the activity of PAL, which were not beneficial to the flavonoid synthesis and provided negative effects for resisting enhanced UV-B radiation. In conclusion, enhanced UV-B radiation caused the increase in the flavonoid synthesis by promoting the activities of PAL, C4H, 4CL, and CHS in soybean seedlings. The treatment of LaCl₃ could change flavonoid synthesis in soybean seedlings under enhanced UV-B radiation by regulating the activities of PAL, C4H, 4CL, and CHS, which is an enzymological mechanism for the regulation of LaCl₃ on flavonoid synthesis in plants under enhanced UV-B radiation.

Study on the infrared radiation performance of Tourmaline composite and its effect on the diesel characteristic

NASA Astrophysics Data System (ADS)

Liao, Jian Bin; Yu, Hong Liang; Sun, Di; Ma, Fong Yuan

2017-09-01

The black tourmaline, magnesium tourmaline, and spinel were ground into powder, and the infrared radiation material was prepared by adding the ceramic powder, clay and the other material into the tourmaline powder according to a certain proportion. The infrared radiation property was tested and analyzed, the diesel was infrared radiation activated by the composite material, and the physicochemical property of fuel oil was analyzed pre-test and post-test. The result shows that the infrared absorption spectrum of the black tourmaline of different particle size is stable. After the diesel oil was infrared radiation activated by tourmaline composite materials, the physicochemical property of diesel oil was changed, the activation energy decreased, the viscosity and surface tension of fuel oil were reduced.

Deficiencies of active electronic radiation protection dosimeters in pulsed fields.

PubMed

Ankerhold, U; Hupe, O; Ambrosi, P

2009-07-01

Nowadays nearly all radiation fields used for X-ray diagnostics are pulsed. These fields are characterised by a high dose rate during the pulse and a short pulse duration in the range of a few milliseconds. The use of active electronic dosimeters has increased in the past few years, but these types of dosimeters might possibly not measure reliably in pulsed radiation fields. Not only personal dosimeters but also area dosimeters that are used mainly for dose rate measurements are concerned. These cannot be substituted by using passive dosimeter types. The characteristics of active electronic dosimeters determined in a continuous radiation field cannot be transferred to those in pulsed fields. Some provisional measurements with typical electronic dosimeters in pulsed radiation fields are presented to reveal this basic problem.

Prediction of iodine-131 biokinetics and radiation doses from therapy on the basis of tracer studies: an important question for therapy planning in nuclear medicine.

PubMed

Willegaignon, José; Pelissoni, Rogério A; Lima, Beatriz C G D; Sapienza, Marcelo T; Coura-Filho, George B; Buchpiguel, Carlos A

2016-05-01

This study aimed to present a comparison of iodine-131 (I) biokinetics and radiation doses to red-marrow (rm) and whole-body (wb), following the administration of tracer and therapeutic activities, as a means of confirming whether I clearance and radiation doses for therapy procedures can be predicted by tracer activities. Eleven differentiated thyroid cancer patients were followed after receiving tracer and therapeutic I activity. Whole-body I clearance was estimated using radiation detectors and OLINDA/EXM software was used to calculate radiation doses to rm and wb. Tracer I activity of 86 (±14) MBq and therapeutic activity of 8.04 (±1.18) GBq were administered to patients, thereby producing an average wb I effective half-time and residence time of, respectively, 13.51 (±4.05) and 23.13 (±5.98) h for tracer activities and 13.32 (±3.38) and 19.63 (±4.77) h for therapy. Radiation doses to rm and wb were, respectively, 0.0467 (±0.0208) and 0.0589 (±0.0207) mGy/MBq in tracer studies and 0.0396 (±0.0169) and 0.0500 (±0.0163) mGy/MBq in therapy. Although the differences were not considered statistically significant between averages, those between the values of effective half-times (P=0.906), residence times (P=0.145), and radiation doses to rm (P=0.393) and to wb (P=0.272), from tracer and therapy procedures, large differences of up to 80% in wb I clearance, and up to 50% in radiation doses were observed when patients were analyzed individually, thus impacting on the total amount of I activity calculated to be safe for application in individual therapy. I biokinetics and radiation doses to rm and wb in therapy procedures are well predicted by diagnostic activities when average values of a group of patients are compared. Nonetheless, when patients are analyzed individually, significant differences may be encountered, thus implying that nuclear medicine therapy-planning requires due consideration of changes in individual patient-body status from initial tracer to final therapy procedures to thus provide appropriate adjustments in therapeutic activities.

Latent transforming growth factor beta1 activation in situ: quantitative and functional evidence after low-dose gamma-irradiation

NASA Technical Reports Server (NTRS)

Ehrhart, E. J.; Segarini, P.; Tsang, M. L.; Carroll, A. G.; Barcellos-Hoff, M. H.; Chatterjee, A. (Principal Investigator)

1997-01-01

The biological activity of transforming growth factor beta1 (TGF-beta) is controlled by its secretion as a latent complex in which it is noncovalently associated with latency-associated peptide (LAP). Activation is the extracellular process in which TGF-beta is released from LAP, and is considered to be a primary regulatory control. We recently reported rapid and persistent changes in TGF-beta immunoreactivity in conjunction with extracellular matrix remodeling in gamma-irradiated mouse mammary gland. Our hypothesis is that these specific changes in immunoreactivity are indicative of latent TGF-beta activation. In the present study, we determined the radiation dose response and tested whether a functional relationship exists between radiation-induced TGF-beta and collagen type III remodeling. After radiation exposures as low as 0.1 Gy, we detected increased TGF-beta immunoreactivity in the mammary epithelium concomitant with decreased LAP immunostaining, which are events consistent with activation. Quantitative image analysis demonstrated a significant (P=0.0005) response at 0.1 Gy without an apparent threshold and a linear dose response to 5 Gy. However, in the adipose stroma, loss of LAP demonstrated a qualitative threshold at 0.5 Gy. Loss of LAP paralleled induction of collagen III immunoreactivity in this tissue compartment. We tested whether TGF-beta mediates collagen III expression by treating animals with TGF-beta panspecific monoclonal antibody, 1D11.16, administered i.p. shortly before irradiation. Radiation-induced collagen III staining in the adipose stroma was blocked in an antibody dose-dependent manner, which persisted through 7 days postirradiation. RNase protection assay revealed that radiation-induced elevation of total gland collagen III mRNA was also blocked by neutralizing antibody treatment. These data provide functional confirmation of the hypothesis that radiation exposure leads to latent TGF-beta activation, support our interpretation of the reciprocal shift in immunoreactivity as evidence of activation, and implicate TGF-beta as a mediator of tissue response to ionizing radiation. The sensitivity of activation to low radiation doses points to a potential role for TGF-beta in orchestrating tissue response to oxidative stress. As such, radiation may be useful as a probe to delineate the consequences of latent TGF-beta activation in situ.

DETERMINATION OF THE RADIOSENSITIVITY OF DIFFERENT BONE GROWTH REGIONS USING Ca$sup 45$ METABOLISM (in German)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kolar, J.; Babicky, A.

1961-02-01

The radiation sensitivity of some bone segments and especially of the growth zones of white rats was examined with the help of Ca/sup 45/. The deviations in the specific activities corresponded not only to the delivered dosage but also to the growth activity of some of the bone segments. After large radiation doses and in more activity growth zones the radiation damage was also greater. These results should give reason in the clinical practice for greater caution in radiation treatment in the area of strongly growing epiphyseal zones (in the area of knee and wrist joints). (auth)

Effects of yak-activated protein on hematopoiesis and related cytokines in radiation-induced injury in mice.

PubMed

Duan, Yabin; Yao, Xingchen; Zhu, Junbo; Li, Yongping; Zhang, Juanling; Zhou, Xuejiao; Qiao, Yijie; Yang, Meng; Li, Xiangyang

2017-12-01

The aim of the present study was to investigate the protective effects of yak-activated protein on hematopoiesis and cytokine function in radiation-induced injury in mice. A total of 180 Kunming mice were randomly divided into three groups (A, B and C). Of these, 60 were randomly divided into a normal control group, a radiation model group, a positive control group and 3 yak-activated protein groups (high, medium and low dose groups; 10, 5 and 2.5 mg/kg, respectively). The other 120 mice were used for the subsequent experiments on days 7 and 14 following radiation. Yak-activated protein was administered orally to mice in the treatment groups and an equal volume of saline was administered orally to mice in the normal control and radiation model groups for 14 days. The positive control group received amifostine (150 mg/kg) via intraperitoneal injection. With the exception of the control group, the groups of mice received a 5 Gy quantity of X-radiation evenly over their whole body once. Changes in the peripheral hemogram, thymus and spleen indices, DNA content in the bone marrow, interleukin (IL)-2 and IL-6 levels, and the expression levels of B cell lymphoma 2 (Bcl-2) and Bcl-2-associated X protein (Bax) following irradiation were assessed. The low dose of yak-activated protein significantly increased Spleen indices in mice 14 days after irradiation and the high and middle dose of yak-activated protein significantly increased Thymus indices in mice 14 days after irradiation (P<0.05) compared with the control group. In addition, hemogram results increased gradually in the low-yak-activated protein dose group and were significantly higher 7 days after irradiation compared with the radiation model group (P<0.05). The DNA content in the bone marrow was markedly increased in the yak-activated protein groups, and increased significantly in the low dose group at 7 days post-irradiation compared with the radiation model group (P<0.05). The IL-2 content was significantly increased in the yak-activated protein groups (P<0.05). Furthermore, Bcl-2 expression was increased and Bax expression was decreased (P<0.05). These results suggest that yak-activated protein exerts protective effects against radiation-induced injury in mice. The optimal effects of yak-activated protein were observed in the medium dose group 14 days after irradiation.

Effects of yak-activated protein on hematopoiesis and related cytokines in radiation-induced injury in mice

PubMed Central

Duan, Yabin; Yao, Xingchen; Zhu, Junbo; Li, Yongping; Zhang, Juanling; Zhou, Xuejiao; Qiao, Yijie; Yang, Meng; Li, Xiangyang

2017-01-01

The aim of the present study was to investigate the protective effects of yak-activated protein on hematopoiesis and cytokine function in radiation-induced injury in mice. A total of 180 Kunming mice were randomly divided into three groups (A, B and C). Of these, 60 were randomly divided into a normal control group, a radiation model group, a positive control group and 3 yak-activated protein groups (high, medium and low dose groups; 10, 5 and 2.5 mg/kg, respectively). The other 120 mice were used for the subsequent experiments on days 7 and 14 following radiation. Yak-activated protein was administered orally to mice in the treatment groups and an equal volume of saline was administered orally to mice in the normal control and radiation model groups for 14 days. The positive control group received amifostine (150 mg/kg) via intraperitoneal injection. With the exception of the control group, the groups of mice received a 5 Gy quantity of X-radiation evenly over their whole body once. Changes in the peripheral hemogram, thymus and spleen indices, DNA content in the bone marrow, interleukin (IL)-2 and IL-6 levels, and the expression levels of B cell lymphoma 2 (Bcl-2) and Bcl-2-associated X protein (Bax) following irradiation were assessed. The low dose of yak-activated protein significantly increased Spleen indices in mice 14 days after irradiation and the high and middle dose of yak-activated protein significantly increased Thymus indices in mice 14 days after irradiation (P<0.05) compared with the control group. In addition, hemogram results increased gradually in the low-yak-activated protein dose group and were significantly higher 7 days after irradiation compared with the radiation model group (P<0.05). The DNA content in the bone marrow was markedly increased in the yak-activated protein groups, and increased significantly in the low dose group at 7 days post-irradiation compared with the radiation model group (P<0.05). The IL-2 content was significantly increased in the yak-activated protein groups (P<0.05). Furthermore, Bcl-2 expression was increased and Bax expression was decreased (P<0.05). These results suggest that yak-activated protein exerts protective effects against radiation-induced injury in mice. The optimal effects of yak-activated protein were observed in the medium dose group 14 days after irradiation. PMID:29285056

Influence of Extraterrestrial Radiation on Radiation Portal Monitors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keller, Paul E.; Kouzes, Richard T.

2009-06-01

Cosmic radiation and solar flares can be a major source of background radiation at the Earth’s surface. This paper examines the relationship between extraterrestrial radiation and the detectable background in radiation portal monitors used for homeland security applications. Background radiation data from 13 radiation portal monitor facilities are examined and compared against external sources of data related to extraterrestrial radiation, including measurements at neutron monitors located at 53 cosmic-ray observatories around the Earth, four polar orbiting satellites, three geostationary satellites, ground-based geomagnetic field data from observatories around the Earth, a solar magnetic index, solar radio flux data, and sunspot activitymore » data. Four-years (January 2003 through December 2006) of data are used in this study, which include the latter part of Solar Cycle 23 as solar activity was on the decline. The analysis shows a significant relationship between some extraterrestrial radiation and the background detected in the radiation portal monitors. A demonstrable decline is shown in the average gamma ray and neutron background at the radiation portal monitors as solar activity declined over the period of the study.« less

Immunological mechanism of low-dose priming radiation resistance in walker-256 tumor model mice

PubMed Central

Feng, Li; Qin, Ling; Guo, Dan; Deng, Daping; Lu, Feng; Li, Hailiang; Bao, Narisu; Yang, Xiting; Ding, Hongyu; Li, Jianguo

2017-01-01

The aim of the present study was to investigate whether low-dose priming radiation induces antitumor immunity that can be augmented by the modulation of natural killer (NK) cell and cytokine activity using a mouse tumor model. Walker-256 cells were injected into the right flank of male BALB/c mice. At 7 days after inoculation, mice were divided into three groups, including group 1,2,3. In group 1 the mice were without radiation, in group 2 the mice were received 2 Gy radiation only, and in group 3 the mice were radiated with a priming dose of 75 mGy followed by 2 Gy radiation after 24 h. On day 21 following the radiation, the tumors were removed and the tumor index (tumor weight as a percentage of body weight) was calculated. At 1, 7, 14 and 21 days following the 2 Gy radiation, mouse splenocytes were isolated to analyze the NK activity and measure the production of the cytokines interleukin-1β, interferon-γ and tumor necrosis factor-α by ELISA. Apoptosis was also measured by flow cytometry. The results demonstrated that priming radiation significantly delayed the tumor growth and prolonged the median survival time to 38 days compared with the 31-day survival in the 2 Gy radiation group. The percentage of apoptotic cells was significantly higher in the mice that received 75 mGy + 2 Gy radiation compared with that in the mice that received 2 Gy alone; by contrast, mice that were not irradiated exhibited a relatively low level of apoptosis. The primed mice had a higher level of NK activity as compared with the mice exposed to 2 Gy radiation only or mice that were not irradiated. Furthermore, cytokine expression remained at a higher level in mice receiving priming dose of radiation compared that in the mice receiving only 2 Gy radiation. In conclusion, the results indicated that low-dose priming X-ray radiation may enhance the NK activity and the levels of cytokines, and that the immune response serves an important role in anticancer therapy, including radiotherapy. PMID:29042994

Small Spacecraft Active Thermal Control: Micro-Vascular Composites Enable Small Satellite Cooling

NASA Technical Reports Server (NTRS)

Ghosh, Alexander

2016-01-01

The Small Spacecraft Integrated Power System with Active Thermal Control project endeavors to achieve active thermal control for small spacecraft in a practical and lightweight structure by circulating a coolant through embedded micro-vascular channels in deployable composite panels. Typically, small spacecraft rely on small body mounted passive radiators to discard heat. This limits cooling capacity and leads to the necessity to design for limited mission operations. These restrictions severely limit the ability of the system to dissipate large amounts of heat from radios, propulsion systems, etc. An actively pumped cooling system combined with a large deployable radiator brings two key advantages over the state of the art for small spacecraft: capacity and flexibility. The use of a large deployable radiator increases the surface area of the spacecraft and allows the radiation surface to be pointed in a direction allowing the most cooling, drastically increasing cooling capacity. With active coolant circulation, throttling of the coolant flow can enable high heat transfer rates during periods of increased heat load, or isolate the radiator during periods of low heat dissipation.

THE EFFECT OF RADIATION AND POLYMYXIN B SULFATE ON THE SERIUM BETA- GLUCURONIDASE ACTIVITY LEVEL IN CANCER PATIENTS: A PRELIMINARY REPORT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bartalos, M.; Gyoerkey, F.

1962-01-01

Serial serum BETA -glucuronidase activity determinations showed a consistently higher level in 50 cancer patients as compared with a group of healthy adults. In 1 group of these patients treated with radiation alone, the serum BETA glucuronidase level rose in all reaching the highest peak about the 12th day. Another group of these cancer patients was treated with radiation and polymyxin B each day for 2 consecutive days. In all, the serum activity showed a sharp fall after the 2nd injection which was followed by clinical improvement. In order to exclude the possibility of a direct deactivating effect of radiationmore » of BETA -glucuronidase in the circulating blood, the following in vitro experiments were performed. A pure crystalline enzyme was dissolved in distilled water to an approximately similar concentration to that found in cancer patients' serums with and without polymyxin and exposed to 50,000 r radiation. This did not lower the enzyme activity level. Pleural fluid from cancer patients showing high BETA -glucoronidase activity, with and without polymyxin, exposed to a similar dose of radiation showed no change in activity. (H.H.D.)« less

Photoprotective Potential of Penta-O-Galloyl-β-DGlucose by Targeting NF-κB and MAPK Signaling in UVB Radiation-Induced Human Dermal Fibroblasts and Mouse Skin.

PubMed

Kim, Byung-Hak; Choi, Mi Sun; Lee, Hyun Gyu; Lee, Song-Hee; Noh, Kum Hee; Kwon, Sunho; Jeong, Ae Jin; Lee, Haeri; Yi, Eun Hee; Park, Jung Youl; Lee, Jintae; Joo, Eun Young; Ye, Sang-Kyu

2015-11-01

Exposure of the skin to ultraviolet radiation can cause skin damage with various pathological changes including inflammation. In the present study, we identified the skin-protective activity of 1,2,3,4,6-penta-O-galloyl-β-D-glucose (pentagalloyl glucose, PGG) in ultraviolet B (UVB) radiation-induced human dermal fibroblasts and mouse skin. PGG exhibited antioxidant activity with regard to intracellular reactive oxygen species (ROS) generation as well as ROS and reactive nitrogen species (RNS) scavenging. Furthermore, PGG exhibited anti-inflammatory activity, inhibiting the activation of nuclear factor-kappaB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling, resulting in inhibition of the expression of pro-inflammatory mediators. Topical application of PGG followed by chronic exposure to UVB radiation in the dorsal skin of hairless mice resulted in a significant decrease in the progression of inflammatory skin damages, leading to inhibited activation of NF-κB signaling and expression of pro-inflammatory mediators. The present study demonstrated that PGG protected from skin damage induced by UVB radiation, and thus, may be a potential candidate for the prevention of environmental stimuli-induced inflammatory skin damage.

Electron beam agrobionanotechnologies for agriculture and food industry enabled by electron accelerators

NASA Astrophysics Data System (ADS)

Pavlov, Y. S.; Revina, A. A.; Souvorova, O. V.; Voropaeva, N. L.; Chekmar, D. V.; Abkhalimov, E. V.; Zavyalov, M. A.; Filippovich, V. P.

2017-12-01

Electron beam (EB) radiation technologies have been employed to increase efficiency of biologically active nanochips developed for agricultural plants seed pre-treatment with purpose of enhancing crop yield and productivity. Iron-containing nanoparticles (NPs), synthesized in reverse micelles following known radiation-chemical technique, have served as a multifunctional biologically active and phytosanitary substance of the chips. Porous chip carriers activation has been performed by EB ionization (doze 20kGy) of the active carbons (AC) prepared from agricultural waste and by-products: Jerusalem artichoke (Helianthus tuberosus) straw, rape (Brassica napus L. ssp. oleifera Metzg) straw, camelina (Camelina sativa (L.) Crantz) straw, wheat (Triticum aestivum) straw. Three methods, UV-VIS spectrophotometry, Electron Paramagnetic Resonance (EPR) spectroscopy, cyclic voltammetry (CV) have been used for process control and characterization of radiation-activated and NPs-modified ACs. The results show a notable effect of ACs activation by electron beam radiation, evidenced by FeNPs-adsorption capacity increase. Studies of the impact of Fe NPs-containing nanochip technology on enhancement of seeds germination rate and seedlings vigour suggest that reported electron beam radiation treatment techniques of the ACs from selected agricultural residues may be advantageous for industrial application.

[Use of terahertz electromagnetic radiation at nitric oxide frequencies for the correction of thyroid functional state during stress].

PubMed

Kirichuk, V F; Tsymbal, A A

2010-01-01

The influence of terahertz electromagnetic radiation at nitric oxide frequencies (150.176-150.664 Ghz) on the functional activity of rat thyroid gland subjected to acute immobilization stress has been studied. It is shown that terahertz radiation totally normalizes thyroid activity in stressed animals within 30 min after application.

The German ISS-experiment Cellular Responses to Radiation in Space (CERASP): The effects of single and combined space flight conditions on mammalian cells

NASA Astrophysics Data System (ADS)

Hellweg, C. E.; Thelen, M.; Arenz, A.; Baumstark-Khan, C.

The combined action of ionizing radiation and microgravity will continue to influence future manned space missions, with special risks for astronauts on the Moon surface or for long duration missions to Mars. There is increasing evidence that basic cellular functions are sensitive not only to radiation but also to microgravity. Previous space flight experiments gave contradictory results: from inhibition of DNA repair by microgravity to enhancement, whereas others did not detect any influence of microgravity on repair. At the Radiation Biology Department of the German Aerospace Center (DLR), recombinant bacterial and mammalian cell systems were developed as reporters for cellular signal transduction modulation by genotoxic environmental conditions. The space experiment “Cellular Responses to Radiation in Space” (CERASP) to be performed at the International Space Station (ISS) will make use of such reporter cell lines thereby supplying basic information on the cellular response to radiation applied in microgravity. One of the biological endpoints will be survival reflected by radiation-dependent reduction of constitutive expression of the enhanced variant of green fluorescent protein (EGFP). A second end-point will be gene activation by space flight conditions in mammalian cells, based on fluorescent promoter reporter systems using the destabilized d2EGFP variant. The promoter element to be investigated reflects the activity of the nuclear factor kappa B (NF-κB) pathway. The NF-κB family of proteins plays a major role in the inflammatory and immune response, cell proliferation and differentiation, apoptosis and tumor genesis. Results obtained with X-rays and accelerated heavy ions produced at the French heavy ion accelerator GANIL imply that densely ionizing radiation has a stronger potential to activate NF-κB dependent gene expression than sparsely ionizing radiation. The correlation of NF-κB activation to negative regulation of apoptosis could favor survival of cells with damaged DNA. A third endpoint to be examined will be DNA damage induced by combined exposure to radiation and microgravity and its repair. In the current work, preparatory experiments for the space experiment CERASP were performed. For radiation exposure on the ISS, an artificial radiation source is necessary since long-term exposure to cosmic radiation of frozen cells for damage accumulation will not be feasible. The biological activity of the designated space radiation source, the β-emitter promethium-147, was evaluated. Different shielding scenarios according to the experiment and safety requirements were evaluated. As growth surface for the human embryonic kidney cells, polytetrafluoroethylene and polyolefin foils were tested. For protection issues, the shielding effect of titanium foils was evaluated. With the prototype Pm-147 radiation source, the requirements of CERASP can be fulfilled with cells growing on the polytetrafluoroethylene foil and titanium foils for safety issues. In this setting, β-rays activated NF-κB-dependent reporter gene expression in human embryonic kidney cells. Regarding cell survival and NF-κB activation, the Pm-147 radiation source meets the requirements of the space experiment CERASP.

Compact optical transconductance varistor

DOEpatents

Sampayan, Stephen

2015-09-22

A compact radiation-modulated transconductance varistor device having both a radiation source and a photoconductive wide bandgap semiconductor material (PWBSM) integrally formed on a substrate so that a single interface is formed between the radiation source and PWBSM for transmitting PWBSM activation radiation directly from the radiation source to the PWBSM.

NCRP Program Area Committee 5: Environmental Radiation and Radioactive Waste Issues.

PubMed

Chen, S Y; Napier, Bruce

2016-02-01

Program Area Committee 5 of the National Council on Radiation Protection and Measurements (NCRP) focuses its activities on environmental radiation and radioactive waste issues. The Committee completed a number of reports in these subject areas, most recently NCRP Report No. 175, Decision Making for Late-Phase Recovery from Major Nuclear or Radiological Incidents. Historically this Committee addressed emerging issues of the nation pertaining to radioactivity or radiation in the environment or radioactive waste issues due either to natural origins or to manmade activities.

Fiber Amplifier Report for NEPP 2008

NASA Technical Reports Server (NTRS)

Thomes, Joe; Ott, Melanie; LaRocca, Frank; Chuska, Rick; Switzer, Rob

2008-01-01

Ongoing qualification activities of LiNbO3 modulators. Passive (unpumped) radiation testing of Er-, Yb-, and Er/Yb-doped fibers: a) Yb-doped fibers exhibit higher radiation resistance than Er-doped fibers; b) Er/Yb co-doped fibers exhibit largest radiation resistance. Active (pumped) radiation testing of Yb-doped fibers conducted at NASA GSFC: a) Typical decay behavior observed; b) No comparison could be made to other fibers due to problems with test setup. Development of new high power fiber terminations.

Radiation sensors for medical, industrial and environmental applications: how to engage with schools and the general public

NASA Astrophysics Data System (ADS)

Seitz, B.; Campos Rivera, N.; Gray, R.; Powell, A.; Thomson, F.

2018-01-01

Radiation, radiation detection and radiation protection are topics in physics and its applications which generate a wide interest in the public. This interest is either generated through medical procedures, applications of nuclear energy or nuclear accidents. The technical nature of these topics usually means that they are not well covered in the normal education stream, opening many opportunities to engage with schools and the general public to showcase the latest developments and their applications. The detection of radiation is at the very heart of understanding radiation, its fascination and associated fears. The outreach group of the nuclear physics group at the University of Glasgow demonstrates a number of successful outreach activities centred around radiation detection and described in this paper, focusing on activities delivered to a variety of audiences and related to applied nuclear physics work within our group. These concentrate on the application of novel sensor technologies for nuclear decommissioning, medical imaging modalities and the monitoring of environmental radioactivity. The paper will provide some necessary background material as well as practical instructions for some of the activities developed.

Radiation-induced interleukin-6 expression through MAPK/p38/NF-kappaB signaling pathway and the resultant antiapoptotic effect on endothelial cells through Mcl-1 expression with sIL6-Ralpha.

PubMed

Chou, Chia-Hung; Chen, Shee-Uan; Cheng, Jason Chia-Hsien

2009-12-01

To investigate the mechanism of interleukin-6 (IL-6) activity induced by ionizing radiation. Human umbilical vascular endothelial cells (HUVECs) were irradiated with different doses to induce IL-6. The IL-6 promoter assay and reverse transcriptase-polymerase chain reaction (RT-PCR) were used to examine transcriptional regulation. Specific chemical inhibitors, decoy double-stranded oligodeoxynucleotides, and Western blotting were conducted to investigate the signal transduction pathway. Recombinant soluble human IL-6 receptor alpha-chain (sIL6-Ralpha) and specific small interfering RNA were used to evaluate the biologic function of radiation-induced IL-6. Four grays of radiation induced the highest level of IL-6 protein. The promoter assay and RT-PCR data revealed that the induction of IL-6 was mediated through transcriptional regulation. The p38 inhibitor SB203580, by blocking nuclear factor-kappaB (NF-kappaB) activation, prevented both the transcriptional and translational regulation of radiation-induced IL-6 expression. The addition of sIL6-Ralpha rescued HUVECs from radiation-induced death in an IL-6 concentratio-dependent manner. The antiapoptotic effect of combined sIL6-Ralpha and radiation-induced IL-6 was inhibited by mcl-1-specific small interfering RNA. Radiation transcriptionally induces IL-6 expression in endothelial cells through mitogen-activated protein kinase/p38-mediated NF-kappaB/IkappaB (inhibitor of NF-kappaB) complex activation. In the presence of sIL6-Ralpha, radiation-induced IL-6 expression acts through Mcl-1 expression to rescue endothelial cells from radiation-induced death.

The response of antioxidant systems in Nostoc sphaeroides against UV-B radiation and the protective effects of exogenous antioxidants

NASA Astrophysics Data System (ADS)

Wang, Gaohong; Hu, Chunxiang; Li, Dunhai; Zhang, Delu; Li, Xiaoyan; Chen, Kun; Liu, Yongding

UV radiation is one of many harmful factors found in space that are detrimental to organisms on earth in space exploration. In the present work, we examined the role of antioxidant system in Nostoc sphaeroides Kütz (Cyanobacterium) and the effects of exogenously applied antioxidant molecules on its photosynthetic rate under UV-B radiation. It was found that UV-B radiation promoted the activity of antioxidant system to protect photosystem II (PSII) and exogenously applied antioxidant: sodium nitroprusside (SNP) and N-acetylcysteine (NAC) had an obvious protection on PSII activity under UV-B radiation. The activity of superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6), peroxidase (POD, EC 1.11.1.7) and content of MDA (malondialdehyde) and ASC (ascorbate) were improved by 0.5 mM and 1 mM SNP, but 0.1 mM SNP decreased the activity of antioxidant system. Addition of exogenous NAC decreased the activity of SOD, POD, CAT and the content MDA and ASC. In contrast, exogenously applied NAC increased GSH content. The results suggest that exogenous SNP and NAC may protect algae by different mechanisms: SNP may play double roles as both sources of reactive free radicals as well as ROS scavengers in mediating the protective role of PSII on algae under UV-B radiation. On the other hand, NAC functions as an antioxidant or precursor of glutathione, which could protect PSII directly from UV-B radiation.

Effect of gamma irradiation on the microbial load, nutrient composition and free radical scavenging activity of Nelumbo nucifera rhizome

NASA Astrophysics Data System (ADS)

Khattak, Khanzadi Fatima; Simpson, Thomas James; Ihasnullah

2009-03-01

The assurance of microbial quality is necessary to make plant materials suitable for human consumption and commercialization. The aim of the present study was to evaluate the possibility to apply the gamma radiation treatment on the rhizome samples of Nelumbo nucifera for microbial decontamination. The radiation processing was carried out at dose levels of 1, 2, 4 and 6 kGy. The irradiated and control samples were analyzed for microbial load, organoleptic acceptance, extraction yield, proximate composition, phenolic contents and DPPH scavenging activity. The results indicated that gamma radiation treatment significantly reduced microbial load and increased the storability of the irradiated samples. The treated samples were also acceptable sensorically. The extraction yield and phenolic contents increased with the increase of radiation dose. Gamma radiation also enhanced the DPPH scavenging activity.

Micro-Fabricated Solid-State Radiation Detectors for Active Personal Dosimetry

NASA Technical Reports Server (NTRS)

Wrbanek, John D.; Wrbanek, Susan Y.; Fralick, Gustave C.; Chen, Liang-Yu

2007-01-01

Active radiation dosimetry is important to human health and equipment functionality for space applications outside the protective environment of a space station or vehicle. This is especially true for long duration missions to the moon, where the lack of a magnetic field offers no protection from space radiation to those on extravehicular activities. In order to improve functionality, durability and reliability of radiation dosimeters for future NASA lunar missions, single crystal silicon carbide devices and scintillating fiber detectors are currently being investigated for applications in advanced extravehicular systems. For many years, NASA Glenn Research Center has led significant efforts in silicon carbide semiconductor technology research and instrumentation research for sensor applications under extreme conditions. This report summarizes the technical progress and accomplishments toward characterization of radiation-sensing components for the recommendation of their fitness for advanced dosimetry development.

Tobacco Smoking During Radiation Therapy for Head-and-Neck Cancer Is Associated With Unfavorable Outcome

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Allen M., E-mail: allen.chen@ucdmc.ucdavis.ed; Chen, Leon M.; Vaughan, Andrew

Purpose: To evaluate the effect of continued cigarette smoking among patients undergoing radiation therapy for head-and-neck cancer by comparing the clinical outcomes among active smokers and quitters. Methods and Materials: A review of medical records identified 101 patients with newly diagnosed squamous cell carcinoma of the head and neck who continued to smoke during radiation therapy. Each active smoker was matched to a control patient who had quit smoking before initiation of radiation therapy. Matching was based on tobacco history (pack-years), primary site, age, sex, Karnofsky Performance Status, disease stage, radiation dose, chemotherapy use, year of treatment, and whether surgicalmore » resection was performed. Outcomes were compared by use of Kaplan-Meier analysis. Normal tissue effects were graded according to the Radiation Therapy Oncology Group/European Organization for the Treatment of Cancer toxicity criteria. Results: With a median follow-up of 49 months, active smokers had significantly inferior 5-year overall survival (23% vs. 55%), locoregional control (58% vs. 69%), and disease-free survival (42% vs. 65%) compared with the former smokers who had quit before radiation therapy (p < 0.05 for all). These differences remained statistically significant when patients treated by postoperative or definitive radiation therapy were analyzed separately. The incidence of Grade 3 or greater late complications was also significantly increased among active smokers compared with former smokers (49% vs. 31%, p = 0.01). Conclusions: Tobacco smoking during radiation therapy for head-and-neck cancer is associated with unfavorable outcomes. Further studies analyzing the biologic and molecular reasons underlying these differences are planned.« less

Tolerance to Gamma Radiation in the Marine Heterotardigrade, Echiniscoides sigismundi.

PubMed

Jönsson, K Ingemar; Hygum, Thomas L; Andersen, Kasper N; Clausen, Lykke K B; Møbjerg, Nadja

2016-01-01

Tardigrades belong to the most radiation tolerant animals on Earth, as documented by a number of studies using both low-LET and high-LET ionizing radiation. Previous studies have focused on semi-terrestrial species, which are also very tolerant to desiccation. The predominant view on the reason for the high radiation tolerance among these semi-terrestrial species is that it relies on molecular mechanisms that evolved as adaptations for surviving dehydration. In this study we report the first study on radiation tolerance in a marine tardigrade, Echiniscoides sigismundi. Adult specimens in the hydrated active state were exposed to doses of gamma radiation from 100 to 5000 Gy. The results showed little effect of radiation at 100 and 500 Gy but a clear decline in activity at 1000 Gy and higher. The highest dose survived was 4000 Gy, at which ca. 8% of the tardigrades were active 7 days after irradiation. LD50 in the first 7 days after irradiation was in the range of 1100-1600 Gy. Compared to previous studies on radiation tolerance in semi-terrestrial and limnic tardigrades, Echiniscoides sigismundi seems to have a lower tolerance. However, the species still fits into the category of tardigrades that have high tolerance to both desiccation and radiation, supporting the hypothesis that radiation tolerance is a by-product of adaptive mechanisms to survive desiccation. More studies on radiation tolerance in tardigrade species adapted to permanently wet conditions, both marine and freshwater, are needed to obtain a more comprehensive picture of the patterns of radiation tolerance.

Tolerance to Gamma Radiation in the Marine Heterotardigrade, Echiniscoides sigismundi

PubMed Central

Hygum, Thomas L.; Andersen, Kasper N.; Clausen, Lykke K. B.; Møbjerg, Nadja

2016-01-01

Tardigrades belong to the most radiation tolerant animals on Earth, as documented by a number of studies using both low-LET and high-LET ionizing radiation. Previous studies have focused on semi-terrestrial species, which are also very tolerant to desiccation. The predominant view on the reason for the high radiation tolerance among these semi-terrestrial species is that it relies on molecular mechanisms that evolved as adaptations for surviving dehydration. In this study we report the first study on radiation tolerance in a marine tardigrade, Echiniscoides sigismundi. Adult specimens in the hydrated active state were exposed to doses of gamma radiation from 100 to 5000 Gy. The results showed little effect of radiation at 100 and 500 Gy but a clear decline in activity at 1000 Gy and higher. The highest dose survived was 4000 Gy, at which ca. 8% of the tardigrades were active 7 days after irradiation. LD50 in the first 7 days after irradiation was in the range of 1100–1600 Gy. Compared to previous studies on radiation tolerance in semi-terrestrial and limnic tardigrades, Echiniscoides sigismundi seems to have a lower tolerance. However, the species still fits into the category of tardigrades that have high tolerance to both desiccation and radiation, supporting the hypothesis that radiation tolerance is a by-product of adaptive mechanisms to survive desiccation. More studies on radiation tolerance in tardigrade species adapted to permanently wet conditions, both marine and freshwater, are needed to obtain a more comprehensive picture of the patterns of radiation tolerance. PMID:27997621

Biochemical changes in the skin of rats exposed to radiation against the background of thermal stress. [X rays; ATPase and creatine kinase activities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matyushichev, V.B.; Taratukhin, V.R.; Shamratova, V.G.

1978-01-01

The effectiveness of exposing rats to different doses of x radiation after submitting them to a heat load, according to the tests of ATPase and creatine kinase activity of aqueous extracts of skin at the relatively late observation period was compared. The effects of the combined factors were monitored by means of a heat load (one group) and exposure to radiation alone in doses of 25, 50, 100, 250, and 400 R (5 groups). The obtained data are indicative of marked specificity of ATPase and creatine kinase reactions to the combined factors. Creatine kinase activity undergoes a 157% change, whereasmore » the mean relative deviation of ATPase activity constitutes only 71% of the normal level. The most effect loads are 36/sup 0/C + 25 R and 36/sup 0/C + 400 R. With all tested doses the extent of the effect of radiation on creatine kinase activity is only negligibly lower than the effectiveness of combined loads, whereas according to the ATPase test, radiation alone induces virtually the same changes in activity as combined factors. ATPase undergoes maximum change after irradiation in doses of 250 and 400 R; delivery of 25 to 100 R is associated with much less marked changes in activity. In contrast, creatine kinase demonstrates maximum sensitivity to radiation in a dosage of 25 R and minimum sensitivity, with a dosage of 100 R. Thermal stress (according to ATPase and creatine kinase activity) has a profound and quite substantial effect on processes of development of radiation lesion. It can be manifested by complete or partial summation of effects of each of the factors, mutual attenuation of effects, or absence of interaction between factors in the combination. All this is indicative of the complexity and differences in mechanisms of expression of effects of the factors used. (ERB)« less

Mississippi CaP HBCU Undergraduate Research Training Program

DTIC Science & Technology

2016-09-01

activities. This activity, occurred once a week (between weeks 4-6) and included touring to Urology, Hematology- Oncology , and Radiation Oncology facilities...Director of UMMC-Cancer Institute, Professor and Chairman, Department of Radiation Oncology University of Mississippi Medical Center, "Precision...Jackson, MS,4Vanderbilt University, Nashville, TN, 5Department of Pathology and Radiation Oncology , Mississippi Medical Center, Jackson, MS Tumor hypoxia

Mechanism of action of ionizing radiation on hexokinase and cholinesterase activity in the rat brain, in the presence of altered function of M-cholinergic structures. [X radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khripchenko, I.P.; Kukulyanskaya, M.F.; Markina, V.L.

1977-01-01

Data are submitted on activity of hexokinase and isozymes thereof, and cholinesterase in subcellular fractions of the brain in the case of inhibition and stimulation of M-cholinoreactive structures under the influence of a relatively small dose, 40 R, of ionizing radiation.

Computational Model of Heat Transfer on the ISS

NASA Technical Reports Server (NTRS)

Torian, John G.; Rischar, Michael L.

2008-01-01

SCRAM Lite (SCRAM signifies Station Compact Radiator Analysis Model) is a computer program for analyzing convective and radiative heat-transfer and heat-rejection performance of coolant loops and radiators, respectively, in the active thermal-control systems of the International Space Station (ISS). SCRAM Lite is a derivative of prior versions of SCRAM but is more robust. SCRAM Lite computes thermal operating characteristics of active heat-transport and heat-rejection subsystems for the major ISS configurations from Flight 5A through completion of assembly. The program performs integrated analysis of both internal and external coolant loops of the various ISS modules and of an external active thermal control system, which includes radiators and the coolant loops that transfer heat to the radiators. The SCRAM Lite run time is of the order of one minute per day of mission time. The overall objective of the SCRAM Lite simulation is to process input profiles of equipment-rack, crew-metabolic, and other heat loads to determine flow rates, coolant supply temperatures, and available radiator heat-rejection capabilities. Analyses are performed for timelines of activities, orbital parameters, and attitudes for mission times ranging from a few hours to several months.

Application and Evaluation of MODIS LAI, FPAR, and Albedo ...

EPA Pesticide Factsheets

MODIS vegetation and albedo products provide a more realistic representation of surface conditions for input to the WRF/CMAQ modeling system. However, the initial evaluation of ingesting MODIS data into the system showed mixed results, with increased bias and error for 2-m temperature and reduced bias and error for 2-m mixing ratio. Recently, the WRF/CMAQ land surface and boundary laywer processes have been updated. In this study, MODIS vegetation and albedo data are input to the updated WRF/CMAQ meteorology and air quality simulations for 2006 over a North American (NA) 12-km domain. The evaluation of the simulation results shows that the updated WRF/CMAQ system improves 2-m temperature estimates over the pre-update base modeling system estimates. The MODIS vegetation input produces a realistic spring green-up that progresses through time from the south to north. Overall, MODIS input reduces 2-m mixing ration bias during the growing season. The NA west shows larger positive O3 bias during the growing season because of reduced gas phase deposition resulting from lower O3 deposition velocities driven by reduced vegetation cover. The O3 bias increase associated with the realistic vegetation representation indicates that further improvement may be needed in the WRF/CMAQ system. The National Exposure Research Laboratory’s Atmospheric Modeling Division (AMAD) conducts research in support of EPA’s mission to protect human health and the environment. AMAD’s rese

[Formation of paroxysmal brain activity in the liquidators of the consequences of the Chernobyl nuclear disaster].

PubMed

Podsonnaya, I V; Shumacher, G I; Efremushkin, G G; Gelobetskaya, E D

2015-01-01

To investigate the effect of ionizing radiation on the formation of paroxysmal brain activity (PBA) in the liquidators of the consequences of the Chernobyl nuclear disaster in view of their age on the date of exposure to radiation. EEG examinations were performed in 105 liquidators of the consequences of the nuclear disaster (LCND) and 90 people without radiation anamnesis (control group). It has been determined that the formation of paroxysmal brain activity in LCND occurs 3.5 times more frequent (p<0.001) and 15-17 years earlier (p<0.001) than in the control group and mainly during the first 10 years after the exposure to radiation. The history of the exposure to ionizing radiation is associated with the increased risk of the development of convulsive PBA as focal seizures by 5.5 times (p<0.001), interictal epileptiform discharges (IED) in EEG by 3.3 times (p<0.001). Radiation effect on LCND under 30 years old increases (as compared to the control group) the risk of the formation of elevated paroxysmal brain activity by 19 times (p<0.001), convulsive epileptic seizures by 33.3 times (p<0.001), interictal epileptiform discharges in EEG by 12 times (p<0.001), asymptomatic focal epileptoid nidus in EEG by 9.3 times (p<0.001). Stimulating effect of ionizing radiation on the development of PBA related to the age on the date of exposure to radiation was found.

Parylene-based active micro space radiator with thermal contact switch

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ueno, Ai; Suzuki, Yuji

2014-03-03

Thermal management is crucial for highly functional spacecrafts exposed to large fluctuations of internal heat dissipation and/or thermal boundary conditions. Since thermal radiation is the only means for heat removal, effective control of radiation is required for advanced space missions. In the present study, a MEMS (Micro Electro Mechanical Systems) active radiator using the contact resistance change has been proposed. Unlike previous bulky thermal louvers/shutters, higher fill factor can be accomplished with an array of electrostatically driven micro diaphragms suspended with polymer tethers. With an early prototype developed with parylene MEMS technologies, radiation heat flux enhancement up to 42% hasmore » been achieved.« less

RADIATION EFFECTS ON IMMUNE MECHANISMS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stoner, R.D.; Hale, W.M.

1963-03-01

Experiments were performed on pathogen-free Swiss albino mice to determine the repressive effect of ionizing radiation on immune mechanisms. In animals given sublethal doses of Co/sup 60/ gamma radiation by acute short-term exposure or by chronic long-term exposure at a low dose rate, ability to produce antibody was inhibited or abolished, and natural resistance and active and passive immunity to pneumococcal and Trichinella infections were severely depressed. It appears that the repression resulted from damage to the cellular defensive mechanisms of the host. Active immunity and natural resistance to influenza virus infections were not altered significantly by radiation. Exposure tomore » radiation enhanced the severity of anaphylactic shock markedly in mice previously sensitized to tetanus toxoid and challenged with tetanus toxoid after radiation. Chronic exposure to radiation caused immediate increased sensitivity to fatal anaphylaxis. (auth)« less

A CONCEPTUAL FRAMEWORK FOR MANAGING RADIATION DOSE TO PATIENTS IN DIAGNOSTIC RADIOLOGY USING REFERENCE DOSE LEVELS.

PubMed

Almén, Anja; Båth, Magnus

2016-06-01

The overall aim of the present work was to develop a conceptual framework for managing radiation dose in diagnostic radiology with the intention to support optimisation. An optimisation process was first derived. The framework for managing radiation dose, based on the derived optimisation process, was then outlined. The outset of the optimisation process is four stages: providing equipment, establishing methodology, performing examinations and ensuring quality. The optimisation process comprises a series of activities and actions at these stages. The current system of diagnostic reference levels is an activity in the last stage, ensuring quality. The system becomes a reactive activity only to a certain extent engaging the core activity in the radiology department, performing examinations. Three reference dose levels-possible, expected and established-were assigned to the three stages in the optimisation process, excluding ensuring quality. A reasonably achievable dose range is also derived, indicating an acceptable deviation from the established dose level. A reasonable radiation dose for a single patient is within this range. The suggested framework for managing radiation dose should be regarded as one part of the optimisation process. The optimisation process constitutes a variety of complementary activities, where managing radiation dose is only one part. This emphasises the need to take a holistic approach integrating the optimisation process in different clinical activities. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Effects of Pharmacological Inhibition and Genetic Deficiency of Plasminogen Activator Inhibitor-1 in Radiation-Induced Intestinal Injury

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abderrahmani, Rym; Francois, Agnes; Buard, Valerie

2009-07-01

Purpose: To investigate effects of plasminogen activator inhibitor 1 (PAI-1) genetic deficiency and pharmacological PAI-1 inhibition with PAI-039 in a mouse model of radiation-induced enteropathy. Methods and Materials: Wild-type (Wt) and PAI-1{sup -/-} knockout mice received a single dose of 19 Gy to an exteriorized localized intestinal segment. Sham and irradiated Wt mice were treated orally with 1 mg/g of PAI-039. Histological modifications were quantified using a radiation injury score. Moreover, intestinal gene expression was monitored by real-time PCR. Results: At 3 days after irradiation, PAI-039 abolished the radiation-induced increase in the plasma active form of PAI-1 and limited themore » radiation-induced gene expression of transforming growth factor {beta}1 (TGF-{beta}1), CTGF, PAI-1, and COL1A2. Moreover, PAI-039 conferred temporary protection against early lethality. PAI-039 treatment limited the radiation-induced increase of CTGF and PAI-1 at 2 weeks after irradiation but had no effect at 6 weeks. Radiation injuries were less severe in PAI-1{sup -/-} mice than in Wt mice, and despite the beneficial effect, 3 days after irradiation, PAI-039 had no effects on microscopic radiation injuries compared to untreated Wt mice. Conclusions: A genetic deficiency of PAI-1 is associated with amelioration of late radiation enteropathy. Pharmacological inhibition of PAI-1 by PAI-039 positively impacts the early, acute phase increase in plasma PAI-1 and the associated radiation-induced gene expression of inflammatory/extracellular matrix proteins. Since PAI-039 has been shown to inhibit the active form of PAI-1, as opposed to the complete loss of PAI-1 in the knockout animals, these data suggest that a PAI-1 inhibitor could be beneficial in treating radiation-induced tissue injury in acute settings where PAI-1 is elevated.« less

Effects of UV-B radiation on photosynthesis activity of Wolffia arrhiza as probed by chlorophyll fluorescence transients

NASA Astrophysics Data System (ADS)

Wang, Gaohong; Hao, Zongjie; Anken, Ralf H.; Lu, Jinying; Liu, Yongding

2010-04-01

The higher plant Wolffia arrhiza is regarded to be well suited concerning the provision of photosynthetic products in the cycle of matter of a Controlled Ecological Life Support System (CELSS) to be established in the context of extraterrestrial, human-based colonization and long-term space flight. Since UV radiation is one major extraterrestrial environmental stress for growth of any plant, effects of UV-B radiation on W. arrhiza were assessed in the present study. We found that UV-B radiation significantly inhibited photosynthetic CO2 assimilation activity, and the contents of chlorophyll a, chlorophyll b (Chl a, Chl b) and carotenoids considerably decreased when plants were exposed to UV-B radiation for 12 h. High UV-B radiation also declined the quantum yield of primary photochemistry (φpo), the quantum yield for electron transport (φEo) and the efficiency per trapped excitation (Ψo) in W. arrhiza simultaneously, while the amount of active PSII reaction centers per excited cross section (RC/CS) and the total number of active reaction centers per absorption (RC/ABS) had comparative changes. These results indicate that the effects of UV-B radiation on photosynthesis of W. arrhiza is due to an inhibition of the electron transport and via inactivation of reaction centers, but the inhibition may take place at more than one site in the photosynthetic apparatus.

Lipoxin A4 inhibits UV radiation-induced skin inflammation and oxidative stress in mice.

PubMed

Martinez, R M; Fattori, V; Saito, P; Melo, C B P; Borghi, S M; Pinto, I C; Bussmann, A J C; Baracat, M M; Georgetti, S R; Verri, W A; Casagrande, R

2018-04-27

Lipoxin A4 (LXA 4 ) is a metabolic product of arachidonic acid. Despite potent anti-inflammatory and pro-resolution activities, it remains to be determined if LXA 4 has effect on ultraviolet (UV) radiation-induced skin inflammation. To investigate the effects of systemic administration with LXA 4 on UV radiation-induced inflammation and oxidative damage in the skin of mice. Varied parameters of inflammation and oxidative stress in the skin of mice were evaluated after UV radiation (4.14 J/cm 2 ). Pretreatment with LXA 4 significantly inhibited UV radiation-induced skin edema and myeloperoxidase activity. LXA 4 efficacy was enhanced by increasing the time of pre-treatment to up to 72 h. LXA 4 reduced UV radiation-induced skin edema, neutrophil recruitment (myeloperoxidase activity and LysM-eGFP + cells), MMP-9 activity, deposition of collagen fibers, epidermal thickness, sunburn cell counts, and production of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6 and IL-33). Depending on the time point, LXA 4 increased the levels of anti-inflammatory cytokines (TGF-β and IL-10). LXA 4 significantly attenuated UV radiation-induced oxidative damage returning the oxidative status to baseline levels in parameters such as ferric reducing ability, scavenging of free radicals, GSH levels, catalase activity and superoxide anion production. LXA 4 also reduced UV radiation-induced gp91 phox [nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 2 (NOX2) subunit] mRNA expression and enhanced nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream target enzyme nicotinamide adenine dinucleotide (phosphate) quinone oxidoreductase (Nqo1) mRNA expression. LXA 4 inhibited UV radiation-induced skin inflammation by diminishing pro-inflammatory cytokine production and oxidative stress as well as inducing anti-inflammatory cytokines and Nrf2. Copyright © 2018. Published by Elsevier B.V.

B-DIM impairs radiation-induced survival pathways independently of androgen receptor expression and augments radiation efficacy in prostate cancer.

PubMed

Singh-Gupta, Vinita; Banerjee, Sanjeev; Yunker, Christopher K; Rakowski, Joseph T; Joiner, Michael C; Konski, Andre A; Sarkar, Fazlul H; Hillman, Gilda G

2012-05-01

Increased consumption of cruciferous vegetables is associated with decreased risk in prostate cancer (PCa). The active compound in cruciferous vegetables appears to be the self dimerized product [3,3'-diindolylmethane (DIM)] of indole-3-carbinol (I3C). Nutritional grade B-DIM (absorption-enhanced) has proven safe in a Phase I trial in PCa. We investigated the anti-cancer activity of B-DIM as a new biological approach to improve the effects of radiotherapy for hormone refractory prostate cancer cells, which were either positive or negative for androgen receptor (AR) expression. B-DIM inhibited cell growth in a dose-dependent manner in both PC-3 (AR-) and C4-2B (AR+) cell lines. B-DIM was effective at increasing radiation-induced cell killing in both cell lines, independently of AR expression. B-DIM inhibited NF-κB and HIF-1α DNA activities and blocked radiation-induced activation of these transcription factors in both PC-3 and C4-2B cells. In C4-2B (AR+) cells, AR expression and nuclear localization were significantly increased by radiation. However, B-DIM abrogated the radiation-induced AR increased expression and trafficking to the nucleus, which was consistent with decreased PSA secretion. In vivo, treatment of PC-3 prostate tumors in nude mice with B-DIM and radiation resulted in significant primary tumor growth inhibition and control of metastasis to para-aortic lymph nodes. These studies demonstrate that B-DIM augments radiation-induced cell killing and tumor growth inhibition. B-DIM impairs critical survival signaling pathways activated by radiation, leading to enhanced cell killing. These novel observations suggest that B-DIM could be used as a safe compound to enhance the efficacy of radiotherapy for castrate-resistant PCa. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Radiological health risks to astronauts from space activities and medical procedures

NASA Technical Reports Server (NTRS)

Peterson, Leif E.; Nachtwey, D. Stuart

1990-01-01

Radiation protection standards for space activities differ substantially from those applied to terrestrial working situations. The levels of radiation and subsequent hazards to which space workers are exposed are quite unlike anything found on Earth. The new more highly refined system of risk management involves assessing the risk to each space worker from all sources of radiation (occupational and non-occupational) at the organ level. The risk coefficients were applied to previous space and medical exposures (diagnostic x ray and nuclear medicine procedures) in order to estimate the radiation-induced lifetime cancer incidence and mortality risk. At present, the risk from medical procedures when compared to space activities is 14 times higher for cancer incidence and 13 times higher for cancer mortality; however, this will change as the per capita dose during Space Station Freedom and interplanetary missions increases and more is known about the risks from exposure to high-LET radiation.

Active Control of Sound Radiation due to Subsonic Wave Scattering from Discontinuities on Thin Elastic Beams.

NASA Astrophysics Data System (ADS)

Guigou, Catherine Renee J.

1992-01-01

Much progress has been made in recent years in active control of sound radiation from vibrating structures. Reduction of the far-field acoustic radiation can be obtained by directly modifying the response of the structure by applying structural inputs rather than by adding acoustic sources. Discontinuities, which are present in many structures are often important in terms of sound radiation due to wave scattering behavior at their location. In this thesis, an edge or boundary type discontinuity (clamped edge) and a point discontinuity (blocking mass) are analytically studied in terms of sound radiation. When subsonic vibrational waves impinge on these discontinuities, large scattered sound levels are radiated. Active control is then achieved by applying either control forces, which approximate shakers, or pairs of control moments, which approximate piezoelectric actuators, near the discontinuity. Active control of sound radiation from a simply-supported beam is also examined. For a single frequency, the flexural response of the beam subject to an incident wave or an input force (disturbance) and to control forces or control moments is expressed in terms of waves of both propagating and near-field types. The far-field radiated pressure is then evaluated in terms of the structural response, using Rayleigh's formula or a stationary phase approach, depending upon the application. The control force and control moment magnitudes are determined by optimizing a quadratic cost function, which is directly related to the control performance. On determining the optimal control complex amplitudes, these can be resubstituted in the constitutive equations for the system under study and the minimized radiated fields can be evaluated. High attenuation in radiated sound power and radiated acoustic pressure is found to be possible when one or two active control actuators are located near the discontinuity, as is shown to be mostly associated with local changes in beam response near the discontinuity. The effect of the control actuators on the far-field radiated pressure, the wavenumber spectrum, the flexural displacement and the near-field time averaged intensity and pressure distributions are studied in order to further understand the control mechanisms. The influence of the near-field structural waves is investigated as well. Some experimental results are presented for comparison.

Are passive smoking, air pollution and obesity a greater mortality risk than major radiation incidents?

PubMed Central

Smith, Jim T

2007-01-01

Background Following a nuclear incident, the communication and perception of radiation risk becomes a (perhaps the) major public health issue. In response to such incidents it is therefore crucial to communicate radiation health risks in the context of other more common environmental and lifestyle risk factors. This study compares the risk of mortality from past radiation exposures (to people who survived the Hiroshima and Nagasaki atomic bombs and those exposed after the Chernobyl accident) with risks arising from air pollution, obesity and passive and active smoking. Methods A comparative assessment of mortality risks from ionising radiation was carried out by estimating radiation risks for realistic exposure scenarios and assessing those risks in comparison with risks from air pollution, obesity and passive and active smoking. Results The mortality risk to populations exposed to radiation from the Chernobyl accident may be no higher than that for other more common risk factors such as air pollution or passive smoking. Radiation exposures experienced by the most exposed group of survivors of Hiroshima and Nagasaki led to an average loss of life expectancy significantly lower than that caused by severe obesity or active smoking. Conclusion Population-averaged risks from exposures following major radiation incidents are clearly significant, but may be no greater than those from other much more common environmental and lifestyle factors. This comparative analysis, whilst highlighting inevitable uncertainties in risk quantification and comparison, helps place the potential consequences of radiation exposures in the context of other public health risks. PMID:17407581

Active electromagnetic invisibility cloaking and radiation force cancellation

NASA Astrophysics Data System (ADS)

Mitri, F. G.

2018-03-01

This investigation shows that an active emitting electromagnetic (EM) Dirichlet source (i.e., with axial polarization of the electric field) in a homogeneous non-dissipative/non-absorptive medium placed near a perfectly conducting boundary can render total invisibility (i.e. zero extinction cross-section or efficiency) in addition to a radiation force cancellation on its surface. Based upon the Poynting theorem, the mathematical expression for the extinction, radiation and amplification cross-sections (or efficiencies) are derived using the partial-wave series expansion method in cylindrical coordinates. Moreover, the analysis is extended to compute the self-induced EM radiation force on the active source, resulting from the waves reflected by the boundary. The numerical results predict the generation of a zero extinction efficiency, achieving total invisibility, in addition to a radiation force cancellation which depend on the source size, the distance from the boundary and the associated EM mode order of the active source. Furthermore, an attractive EM pushing force on the active source directed toward the boundary or a repulsive pulling one pointing away from it can arise accordingly. The numerical predictions and computational results find potential applications in the design and development of EM cloaking devices, invisibility and stealth technologies.

Analytical-HZETRN Model for Rapid Assessment of Active Magnetic Radiation Shielding

NASA Technical Reports Server (NTRS)

Washburn, S. A.; Blattnig, S. R.; Singleterry, R. C.; Westover, S. C.

2014-01-01

The use of active radiation shielding designs has the potential to reduce the radiation exposure received by astronauts on deep-space missions at a significantly lower mass penalty than designs utilizing only passive shielding. Unfortunately, the determination of the radiation exposure inside these shielded environments often involves lengthy and computationally intensive Monte Carlo analysis. In order to evaluate the large trade space of design parameters associated with a magnetic radiation shield design, an analytical model was developed for the determination of flux inside a solenoid magnetic field due to the Galactic Cosmic Radiation (GCR) radiation environment. This analytical model was then coupled with NASA's radiation transport code, HZETRN, to account for the effects of passive/structural shielding mass. The resulting model can rapidly obtain results for a given configuration and can therefore be used to analyze an entire trade space of potential variables in less time than is required for even a single Monte Carlo run. Analyzing this trade space for a solenoid magnetic shield design indicates that active shield bending powers greater than 15 Tm and passive/structural shielding thicknesses greater than 40 g/cm2 have a limited impact on reducing dose equivalent values. Also, it is shown that higher magnetic field strengths are more effective than thicker magnetic fields at reducing dose equivalent.

Naturally induced secondary radiation in interplanetary space: Preliminary analyses for gamma radiation and radioisotope production from thermal neutron activation

NASA Technical Reports Server (NTRS)

Plaza-Rosado, Heriberto

1991-01-01

Thermal neutron activation analyses were carried out for various space systems components to determine gamma radiation dose rates and food radiation contamination levels. The space systems components selected were those for which previous radiation studies existed. These include manned space vehicle radiation shielding, liquid hydrogen propellant tanks for a Mars mission, and a food supply used as space vehicle radiation 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 radiation 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 induced radioactivity was below the accepted maximum permissible concentrations.

Naturally induced secondary radiation in interplanetary space: Preliminary analyses for gamma radiation and radioisotope production from thermal neutron activation

NASA Astrophysics Data System (ADS)

Plaza-Rosado, Heriberto

1991-09-01

Thermal neutron activation analyses were carried out for various space systems components to determine gamma radiation dose rates and food radiation contamination levels. The space systems components selected were those for which previous radiation studies existed. These include manned space vehicle radiation shielding, liquid hydrogen propellant tanks for a Mars mission, and a food supply used as space vehicle radiation 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 radiation 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 induced radioactivity was below the accepted maximum permissible concentrations.

Ultrasound-mediated microbubble enhancement of radiation therapy studied using three-dimensional high-frequency power Doppler ultrasound.

PubMed

Kwok, Sheldon J J; El Kaffas, Ahmed; Lai, Priscilla; Al Mahrouki, Azza; Lee, Justin; Iradji, Sara; Tran, William Tyler; Giles, Anoja; Czarnota, Gregory J

2013-11-01

Tumor responses to high-dose (>8 Gy) radiation therapy are tightly connected to endothelial cell death. In the study described here, we investigated whether ultrasound-activated microbubbles can locally enhance tumor response to radiation treatments of 2 and 8 Gy by mechanically perturbing the endothelial lining of tumors. We evaluated vascular changes resulting from combined microbubble and radiation treatments using high-frequency 3-D power Doppler ultrasound in a breast cancer xenograft model. We compared treatment effects and monitored vasculature damage 3 hours, 24 hours and 7 days after treatment delivery. Mice treated with 2 Gy radiation and ultrasound-activated microbubbles exhibited a decrease in vascular index to 48 ± 10% at 24 hours, whereas vascular indices of mice treated with 2 Gy radiation alone or microbubbles alone were relatively unchanged at 95 ± 14% and 78 ± 14%, respectively. These results suggest that ultrasound-activated microbubbles enhance the effects of 2 Gy radiation through a synergistic mechanism, resulting in alterations of tumor blood flow. This novel therapy may potentiate lower radiation doses to preferentially target endothelial cells, thus reducing effects on neighboring normal tissue and increasing the efficacy of cancer treatments. Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.

The effects of UV-B radiation intensity on biochemical parameters and active ingredients in flowers of Qi chrysanthemum and Huai chrysanthemum.

PubMed

Yao, Xiao-Qin; Chu, Jian-Zhou; He, Xue-Li; Si, Chao

2014-01-01

The article studied UV-B effects on biochemical parameters and active ingredients in flowers of Qi chrysanthemum and Huai chrysanthemum during the bud stage. The experiment included four UV-B radiation levels (CK, ambient UV-B; T1, T2 and T3 indicated a 5%, 10% and 15% increase in ambient UV-BBE, respectively) to determine the optimal UV-B radiation intensity in regulating active ingredients level in flowers of two chrysanthemum varieties. Flower dry weight of two cultivars was not affected by UV-B radiation under experimental conditions reported here. UV-B treatments significantly increased the rate of superoxide radical production, hydrogen peroxide (H2O2) (except for T1) and malondialdehyde concentration in flowers of Huai chrysanthemum and H2O2 concentration in flowers of Qi chrysanthemum. T2 and T3 treatments induced a significant increase in phenylalanine ammonia lyase enzyme (PAL) activity, anthocyanins, proline, ascorbic acid, chlorogenic acid and flavone content in flowers of two chrysanthemum varieties, and there were no significant differences in PAL activity, ascorbic acid, flavone and chlorogenic acid content between the two treatments. These results indicated that appropriate UV-B radiation intensity did not result in the decrease in flower yield, and could regulate PAL activity and increase active ingredients content in flowers of two chrysanthemum varieties. © 2014 The American Society of Photobiology.

Combined Impact of Gamma and Laser Radiation on Peripheral Blood of Rats in vivo

NASA Astrophysics Data System (ADS)

Zalesskaya, G. A.; Batay, L. E.; Koshlan, I. V.; Nasek, V. M.; Zilberman, R. D.; Milevich, T. I.; Govorun, R. D.; Koshlan, N. A.; Blaga, P.

2017-11-01

The impact of γ radiation of 137Cs (doses of 1 and 3 Gy), low-intensity laser radiation (λ = 670 nm, 5.3 or 10.6 J/cm2) as well as the influence of consecutive laser and γ radiation on peripheral blood and blood cells (erythrocytes, leukocytes, lymphocytes, granulocytes) were studied by analyzing the number of blood cells, blood absorption spectra, and activity of antioxidant defense enzymes. Two series of experiments were performed on four groups of rats. The rats of the control group (group 1) were not exposed to γ or laser radiation. In the experimental groups, single irradiation of the whole body of rats with γ radiation (group 2), three- or four-day over-vein irradiation of blood in the tail vein by low-intensity laser radiation (group 3), and successive three- or four-day irradiation of blood by laser and then a single irradiation of the whole body with γ radiation (group 4) were performed. It was shown that changes of the blood cell content in the experimental groups are accompanied by changes in the spectral characteristics of the blood and the activity of antioxidant defense enzymes. The radioprotective effect of low-intensity laser radiation is manifested as an increase in the average number of leukocytes and lymphocytes in the group as compared with the postradiation, as well as an increase in the activity of antioxidant protection enzymes. The possibility of using low-intensity optical radiation for correction of hematological disorders caused by ionizing radiation is discussed.

Radiation From Solar Activity | Radiation Protection | US EPA

EPA Pesticide Factsheets

2017-08-07

Solar flares, coronal mass ejections (CMEs) and geomagnetic storms from the sun can send extreme bursts of ionizing radiation and magnetic energy toward Earth. Some of this energy is in the form ionizing radiation and some of the energy is magnetic energy.

78 FR 5813 - 2013 Assuring Radiation Protection

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-28

...] 2013 Assuring Radiation Protection AGENCY: Food and Drug Administration, HHS. ACTION: Notice. SUMMARY... of the Center for Devices and Radiological Health (CDRH) radiation protection program. The goal of the 2013 Assuring Radiation Protection will be to coordinate Federal, State, and Tribal activities to...

Inhibiting the phosphatidylinositide 3-kinase pathway blocks radiation-induced metastasis associated with Rho-GTPase and Hypoxia-inducible factor-1 activity.

PubMed

Burrows, Natalie; Telfer, Brian; Brabant, Georg; Williams, Kaye J

2013-09-01

Undifferentiated follicular and anaplastic thyroid tumours often respond poorly to radiotherapy and show increased metastatic potential. We evaluated radiation-induced effects on metastasis in thyroid carcinoma cells and tumours, mechanistically focusing on phosphatidylinositide 3-kinase (PI3K) and associated pathways. Migration was analysed in follicular (FTC133) and anaplastic (8505c) cells following radiotherapy (0-6 Gray) with concomitant pharmacological (GDC-0941) or genetic inhibition of PI3K. Hypoxia-inducible factor-1 (HIF-1)-activity was measured using luciferase reporter assays and was inhibited using a dominant-negative variant. Activation and subcellular localisation of target proteins were assessed via Western blot and immunofluorescence. In vivo studies used FTC133 xenografts with metastatic lung dissemination assessed ex vivo. Radiation induced migration in a HIF-dependent manner in FTC133 cells but decreased migration in 8505c's. Post-radiation HIF-activity correlated with migratory phenotype. PI3K-targeting inhibited migration under basal and irradiated conditions through inhibition of HIF-1α, Rho-GTPase expression/activity and localisation whilst having little effect on src/FAK. In vivo, radiation induced PI3K, HIF, Rho-GTPases and src but only PI3K, HIF and Rho-GTPases were inhibited by GDC-0941. Co-treatment with GDC-0941 and radiation significantly reduced metastatic dissemination versus radiotherapy alone. Radiation modifies metastatic characteristics of thyroid carcinoma cells, which can be successfully inhibited by targeting PI3K using GDC-0941 in vitro and in vivo. Copyright © 2013 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

Glass transition in thaumatin crystals revealed through temperature-dependent radiation-sensitivity measurements.

PubMed

Warkentin, Matthew; Thorne, Robert E

2010-10-01

The temperature-dependence of radiation damage to thaumatin crystals between T = 300 and 100 K is reported. The amount of damage for a given dose decreases sharply as the temperature decreases from 300 to 220 K and then decreases more gradually on further cooling below the protein-solvent glass transition. Two regimes of temperature-activated behavior were observed. At temperatures above ∼200 K the activation energy of 18.0 kJ mol(-1) indicates that radiation damage is dominated by diffusive motions in the protein and solvent. At temperatures below ∼200 K the activation energy is only 1.00 kJ mol(-1), which is of the order of the thermal energy. Similar activation energies describe the temperature-dependence of radiation damage to a variety of solvent-free small-molecule organic crystals over the temperature range T = 300-80 K. It is suggested that radiation damage in this regime is vibrationally assisted and that the freezing-out of amino-acid scale vibrations contributes to the very weak temperature-dependence of radiation damage below ∼80 K. Analysis using the radiation-damage model of Blake and Phillips [Blake & Phillips (1962), Biological Effects of Ionizing Radiation at the Molecular Level, pp. 183-191] indicates that large-scale conformational and molecular motions are frozen out below T = 200 K but become increasingly prevalent and make an increasing contribution to damage at higher temperatures. Possible alternative mechanisms for radiation damage involving the formation of hydrogen-gas bubbles are discussed and discounted. These results have implications for mechanistic studies of proteins and for studies of the protein glass transition. They also suggest that data collection at T ≃ 220 K may provide a viable alternative for structure determination when cooling-induced disorder at T = 100 is excessive.

Infrared irradiation alters the expression of matrix metalloproteinases and glycosaminoglycans in the cornea and crystalline lens.

PubMed

Dadoukis, Panagiotis; Klagas, Ioannis; Komnenou, Anastasia; Karakiulakis, George; Karoutis, Athanasios; Karampatakis, Vassilios; Papakonstantinou, Eleni

2013-08-01

Prolonged exposure to infrared (IR) radiation is associated with different types of damage to cornea and lens. The aim of our study was to investigate the effect of acute and chronic exposure to IR radiation on the activity of matrix metalloproteinase-2 (MMP-2) and MMP-9 and on the expression of glycosaminoglycans (GAG) in the rabbit cornea and crystalline lens. New Zealand rabbits were subjected to IR radiation for 4 months (chronic exposure to IR) or to normal light (control group). In experiments regarding acute exposure, animals were subjected to IR radiation or normal light for 12 h, in the presence of 0.1% diclofenac sodium (eye drops instilled in the right eye of animals) or saline (instilled in the left eye of animals). The cornea and lens were dissected away and homogenized. The activity of MMP-2 and MMP-9 was assayed by gelatine zymography. Total GAG were isolated from tissue specimens after lipid extraction and extensive digestion with pronase and DNase and characterized by treatment with GAG-degrading enzymes, followed by electrophoresis on cellulose acetate membranes. Acute or chronic exposure to IR radiation induced the activity of MMP-2 in cornea and lens, whereas only acute IR radiation increased the content of heparan sulphate in crystalline lens. Local administration of diclofenac sodium did not prevent the above effects of acute IR radiation. The detrimental effects of excessive or prolonged exposure of the eyes to IR radiation are associated with induced activity of MMP-2 in cornea and lens and alterations in the content of heparan sulphate in lens. Thus, MMP and GAG may offer alternative targets for pharmacological intervention to confront ocular damages associated with IR radiation.

Effectiveness Evaluation Method of Anti-Radiation Missile against Active Decoy

NASA Astrophysics Data System (ADS)

Tang, Junyao; Cao, Fei; Li, Sijia

2017-06-01

In the problem of anti-radiation missile against active decoy, whether the ARM can effectively kill the target radiation source and bait is an important index for evaluating the operational effectiveness of the missile. Aiming at this problem, this paper proposes a method to evaluate the effect of ARM against active decoy. Based on the calculation of ARM’s ability to resist the decoy, the paper proposes a method to evaluate the decoy resistance based on the key components of the hitting radar. The method has the advantages of scientific and reliability.

Space-type radiation induces multimodal responses in the mouse gut microbiome and metabolome.

PubMed

Casero, David; Gill, Kirandeep; Sridharan, Vijayalakshmi; Koturbash, Igor; Nelson, Gregory; Hauer-Jensen, Martin; Boerma, Marjan; Braun, Jonathan; Cheema, Amrita K

2017-08-18

Space travel is associated with continuous low dose rate exposure to high linear energy transfer (LET) radiation. Pathophysiological manifestations after low dose radiation exposure are strongly influenced by non-cytocidal radiation effects, including changes in the microbiome and host gene expression. Although the importance of the gut microbiome in the maintenance of human health is well established, little is known about the role of radiation in altering the microbiome during deep-space travel. Using a mouse model for exposure to high LET radiation, we observed substantial changes in the composition and functional potential of the gut microbiome. These were accompanied by changes in the abundance of multiple metabolites, which were related to the enzymatic activity of the predicted metagenome by means of metabolic network modeling. There was a complex dynamic in microbial and metabolic composition at different radiation doses, suggestive of transient, dose-dependent interactions between microbial ecology and signals from the host's cellular damage repair processes. The observed radiation-induced changes in microbiota diversity and composition were analyzed at the functional level. A constitutive change in activity was found for several pathways dominated by microbiome-specific enzymatic reactions like carbohydrate digestion and absorption and lipopolysaccharide biosynthesis, while the activity in other radiation-responsive pathways like phosphatidylinositol signaling could be linked to dose-dependent changes in the abundance of specific taxa. The implication of microbiome-mediated pathophysiology after low dose ionizing radiation may be an unappreciated biologic hazard of space travel and deserves experimental validation. This study provides a conceptual and analytical basis of further investigations to increase our understanding of the chronic effects of space radiation on human health, and points to potential new targets for intervention in adverse radiation effects.

Protective effect of α-lipoic acid against radiation-induced fibrosis in mice

PubMed Central

Ryu, Seung-Hee; Park, Eun-Young; Kwak, Sungmin; Heo, Seung-Ho; Ryu, Je-Won; Park, Jin-hong

2016-01-01

Radiation-induced fibrosis (RIF) is one of the most common late complications of radiation therapy. We found that α-lipoic acid (α-LA) effectively prevents RIF. In RIF a mouse model, leg contracture assay was used to test the in vivo efficacy of α-LA. α-LA suppressed the expression of pro-fibrotic genes after irradiation, both in vivo and in vitro, and inhibited the up-regulation of TGF-β1-mediated p300/CBP activity. Thus, α-LA prevents radiation-induced fibrosis (RIF) by inhibiting the transcriptional activity of NF-κB through inhibition of histone acetyltransferase activity. α-LA is a new therapeutic methods that can be used in the prevention-treatment of RIF. PMID:26799284

Application of an Informatics-Based Decision-Making Framework and Process to the Assessment of Radiation Safety in Nanotechnology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoover, Mark D.; Myers, David S.; Cash, Leigh J.

The National Council on Radiation Protection and Measurements (NCRP) has established NCRP Scientific Committee 2-6 to develop a report on the current state of knowledge and guidance for radiation safety programs involved with nanotechnology. Nanotechnology is the understanding and control of matter at the nanoscale, at dimensions between approximately 1 and 100 nanometers, where unique phenomena enable novel applications. While the full report is in preparation, this article presents and applies an informatics-based decision-making framework and process through which the radiation protection community can anticipate that nano-enabled applications, processes, nanomaterials, and nanoparticles are likely to become present or are alreadymore » present in radiation-related activities; recognize specific situations where environmental and worker safety, health, well-being, and productivity may be affected by nano-related activities; evaluate how radiation protection practices may need to be altered to improve protection; control information, interpretations, assumptions, and conclusions to implement scientifically sound decisions and actions; and confirm that desired protection outcomes have been achieved. This generally applicable framework and supporting process can be continuously applied to achieve health and safety at the convergence of nanotechnology and radiation-related activities.« less

Response of antioxidant defense system to laser radiation apical meristem of Isatis indigotica seedlings exposed to UV-B.

PubMed

Chen, Yi-Ping

2009-07-01

To determine the response of antioxidant defense system to laser radiation apical meristem of Isatis indigotica seedlings, Isatis indigotica seedlings were subjected to UV-B radiation (10.08 kJ m(-2)) for 8 h day(-1) for 8 days (PAR, 220 micromol m(-2) s(-1)) and then exposed to He-Ne laser radiation (633 nm; 5.23 mW mm(-2); beam diameter: 1.5 mm) for 5 min each day without ambient light radiation. Changes in free radical elimination systems were measured, the results indicate that: (1) UV-B radiation enhanced the concentration of Malondialdahyde (MDA) and decreased the activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) in seedlings compared with the control. The concentration of MDA was decreased and the activities of SOD, CAT and POD were increased when seedlings were subjected to elevated UV-B damage followed by laser; (2) the concentration of UV absorbing compounds and proline were increased progressively with UV-B irradiation, laser irradiation and He-Ne laser irradiation plus UV-B irradiation compared with the control. These results suggest that laser radiation has an active function in repairing UV-B-induced lesions in seedlings.

Application of an informatics-based decision-making framework and process to the assessment of radiation safety in nanotechnology.

PubMed

Hoover, Mark D; Myers, David S; Cash, Leigh J; Guilmette, Raymond A; Kreyling, Wolfgang G; Oberdörster, Günter; Smith, Rachel; Cassata, James R; Boecker, Bruce B; Grissom, Michael P

2015-02-01

The National Council on Radiation Protection and Measurements (NCRP) established NCRP Scientific Committee 2-6 to develop a report on the current state of knowledge and guidance for radiation safety programs involved with nanotechnology. Nanotechnology is the understanding and control of matter at the nanoscale, at dimensions between ∼1 and 100 nm, where unique phenomena enable novel applications. While the full report is in preparation, this paper presents and applies an informatics-based decision-making framework and process through which the radiation protection community can anticipate that nano-enabled applications, processes, nanomaterials, and nanoparticles are likely to become present or are already present in radiation-related activities; recognize specific situations where environmental and worker safety, health, well-being, and productivity may be affected by nano-related activities; evaluate how radiation protection practices may need to be altered to improve protection; control information, interpretations, assumptions, and conclusions to implement scientifically sound decisions and actions; and confirm that desired protection outcomes have been achieved. This generally applicable framework and supporting process can be continuously applied to achieve health and safety at the convergence of nanotechnology and radiation-related activities.

Application of an Informatics-Based Decision-Making Framework and Process to the Assessment of Radiation Safety in Nanotechnology

DOE PAGES

Hoover, Mark D.; Myers, David S.; Cash, Leigh J.; ...

2015-01-01

The National Council on Radiation Protection and Measurements (NCRP) has established NCRP Scientific Committee 2-6 to develop a report on the current state of knowledge and guidance for radiation safety programs involved with nanotechnology. Nanotechnology is the understanding and control of matter at the nanoscale, at dimensions between approximately 1 and 100 nanometers, where unique phenomena enable novel applications. While the full report is in preparation, this article presents and applies an informatics-based decision-making framework and process through which the radiation protection community can anticipate that nano-enabled applications, processes, nanomaterials, and nanoparticles are likely to become present or are alreadymore » present in radiation-related activities; recognize specific situations where environmental and worker safety, health, well-being, and productivity may be affected by nano-related activities; evaluate how radiation protection practices may need to be altered to improve protection; control information, interpretations, assumptions, and conclusions to implement scientifically sound decisions and actions; and confirm that desired protection outcomes have been achieved. This generally applicable framework and supporting process can be continuously applied to achieve health and safety at the convergence of nanotechnology and radiation-related activities.« less

Scale models: A proven cost-effective tool for outage planning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, R.; Segroves, R.

1995-03-01

As generation costs for operating nuclear stations have risen, more nuclear utilities have initiated efforts to improve cost effectiveness. Nuclear plant owners are also being challenged with lower radiation exposure limits and new revised radiation protection related regulations (10 CFR 20), which places further stress on their budgets. As source term reduction activities continue to lower radiation fields, reducing the amount of time spent in radiation fields becomes one of the most cost-effective ways of reducing radiation exposure. An effective approach for minimizing time spent in radiation areas is to use a physical scale model for worker orientation planning andmore » monitoring maintenance, modifications, and outage activities. To meet the challenge of continued reduction in the annual cumulative radiation exposures, new cost-effective tools are required. One field-tested and proven tool is the physical scale model.« less

Compton effect thermally activated depolarization dosimeter

DOEpatents

Moran, Paul R.

1978-01-01

A dosimetry technique for high-energy gamma radiation or X-radiation employs the Compton effect in conjunction with radiation-induced thermally activated depolarization phenomena. A dielectric material is disposed between two electrodes which are electrically short circuited to produce a dosimeter which is then exposed to the gamma or X radiation. The gamma or X-radiation impinging on the dosimeter interacts with the dielectric material directly or with the metal composing the electrode to produce Compton electrons which are emitted preferentially in the direction in which the radiation was traveling. A portion of these electrons becomes trapped in the dielectric material, consequently inducing a stable electrical polarization in the dielectric material. Subsequent heating of the exposed dosimeter to the point of onset of ionic conductivity with the electrodes still shorted through an ammeter causes the dielectric material to depolarize, and the depolarization signal so emitted can be measured and is proportional to the dose of radiation received by the dosimeter.

Activation of Protease Activated Receptor 2 by Exogenous Agonist Exacerbates Early Radiation Injury in Rat Intestine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang Junru; Boerma, Marjan; Kulkarni, Ashwini

2010-07-15

Purpose: Protease-activated receptor-2 (PAR{sub 2}) is highly expressed throughout the gut and regulates the inflammatory, mitogenic, fibroproliferative, and nociceptive responses to injury. PAR{sub 2} is strikingly upregulated and exhibits increased activation in response to intestinal irradiation. We examined the mechanistic significance of radiation enteropathy development by assessing the effect of exogenous PAR{sub 2} activation. Methods and Materials: Rat small bowel was exposed to localized single-dose radiation (16.5 Gy). The PAR{sub 2} agonist (2-furoyl-LIGRLO-NH{sub 2}) or vehicle was injected intraperitoneally daily for 3 days before irradiation (before), for 7 days after irradiation (after), or both 3 days before and 7 daysmore » after irradiation (before-after). Early and delayed radiation enteropathy was assessed at 2 and 26 weeks after irradiation using quantitative histologic examination, morphometry, and immunohistochemical analysis. Results: The PAR{sub 2} agonist did not elicit changes in the unirradiated (shielded) intestine. In contrast, in the irradiated intestine procured 2 weeks after irradiation, administration of the PAR{sub 2} agonist was associated with more severe mucosal injury and increased intestinal wall thickness in all three treatment groups (p <.05) compared with the vehicle-treated controls. The PAR{sub 2} agonist also exacerbated the radiation injury score, serosal thickening, and mucosal inflammation (p <.05) in the before and before-after groups. The short-term exogenous activation of PAR{sub 2} did not affect radiation-induced intestinal injury at 26 weeks. Conclusion: The results of the present study support a role for PAR{sub 2} activation in the pathogenesis of early radiation-induced intestinal injury. Pharmacologic PAR{sub 2} antagonists might have the potential to reduce the intestinal side effects of radiotherapy and/or as countermeasures in radiologic accidents or terrorism scenarios.« less

Clinical Advances of Hypoxia-Activated Prodrugs in Combination With Radiation Therapy.

PubMed

Mistry, Ishna N; Thomas, Matthew; Calder, Ewen D D; Conway, Stuart J; Hammond, Ester M

2017-08-01

With the increasing incidence of cancer worldwide, the need for specific, effective therapies is ever more urgent. One example of targeted cancer therapeutics is hypoxia-activated prodrugs (HAPs), also known as bioreductive prodrugs. These prodrugs are inactive in cells with normal oxygen levels but in hypoxic cells (with low oxygen levels) undergo chemical reduction to the active compound. Hypoxia is a common feature of solid tumors and is associated with a more aggressive phenotype and resistance to all modes of therapy. Therefore, the combination of radiation therapy and bioreductive drugs presents an attractive opportunity for synergistic effects, because the HAP targets the radiation-resistant hypoxic cells. Hypoxia-activated prodrugs have typically been precursors of DNA-damaging agents, but a new generation of molecularly targeted HAPs is emerging. By targeting proteins associated with tumorigenesis and survival, these compounds may result in greater selectivity over healthy tissue. We review the clinical progress of HAPs as adjuncts to radiation therapy and conclude that the use of HAPs alongside radiation is vastly underexplored at the clinical level. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Comparison of the measured and predicted response of the Earth Radiation Budget Experiment active cavity radiometer during solar observations

NASA Technical Reports Server (NTRS)

Mahan, J. R.; Tira, N. E.; Lee, Robert B., III; Keynton, R. J.

1989-01-01

The Earth Radiation Budget Experiment consists of an array of radiometric instruments placed in earth orbit by the National Aeronautics and Space Administration to monitor the longwave and visible components of the earth's radiation budget. Presented is a dynamic electrothermal model of the active cavity radiometer used to measure the earth's total radiative exitance. Radiative exchange is modeled using the Monte Carlo method and transient conduction is treated using the finite element method. Also included is the feedback circuit which controls electrical substitution heating of the cavity. The model is shown to accurately predict the dynamic response of the instrument during solar calibration.

Fourier Transform IR Spectroscopic Study of Nano-ZrO2 + Nano-SiO2 + Nano-H2O Systems Upon the Action of Gamma Radiation

NASA Astrophysics Data System (ADS)

Agayev, T. N.; Gadzhieva, N. N.; Melikova, S. Z.

2018-05-01

The radiation decomposition of water in a nano-ZrO2 + nano-SiO2 + H2O system at 300 K by the action of gamma radiation has been studied by Fourier transform IR spectroscopy. Water adsorption in the zirconium and silicon nanooxides is attributed to molecular and dissociative mechanisms. Active intermediates in this radiation-induced heterogeneous decomposition of water were detected including zirconium and silicon hydrides and hydroxyl groups. Variation in the ratio of ZrO2 and SiO2 nanopowders was shown to lead to change in their radiation catalytic activity compared to initial ZrO2.

A semiconductor radiation imaging pixel detector for space radiation dosimetry

NASA Astrophysics Data System (ADS)

Kroupa, Martin; Bahadori, Amir; Campbell-Ricketts, Thomas; Empl, Anton; Hoang, Son Minh; Idarraga-Munoz, John; Rios, Ryan; Semones, Edward; Stoffle, Nicholas; Tlustos, Lukas; Turecek, Daniel; Pinsky, Lawrence

2015-07-01

Progress in the development of high-performance semiconductor radiation imaging pixel detectors based on technologies developed for use in high-energy physics applications has enabled the development of a completely new generation of compact low-power active dosimeters and area monitors for use in space radiation environments. Such detectors can provide real-time information concerning radiation exposure, along with detailed analysis of the individual particles incident on the active medium. Recent results from the deployment of detectors based on the Timepix from the CERN-based Medipix2 Collaboration on the International Space Station (ISS) are reviewed, along with a glimpse of developments to come. Preliminary results from Orion MPCV Exploration Flight Test 1 are also presented.

The Potential Radiative Forcing of Global Land Use and Land Cover Change Activities

NASA Astrophysics Data System (ADS)

Ward, D. S.; Mahowald, N. M.; Kloster, S.

2014-12-01

Given the expected increase in pressure on land resources over the next century, there is a need to understand the total impacts of activities associated with land use and land cover change (LULCC). Here we quantify these impacts using the radiative forcing metric, including forcings from changes in long-lived greenhouse gases, tropospheric ozone, aerosol effects, and land surface albedo. We estimate radiative forcings from the different agents for historical LULCC and for six future projections using simulations from the National Center for Atmospheric Research Community Land Model and Community Atmosphere Models and additional offline analyses. When all forcing agents are considered together we show that 45% (+30%, -20%) of the present-day (2010) anthropogenic radiative forcing can be attributed to LULCC. Changes in the emission of non-CO2 greenhouse gases and aerosols from LULCC enhance the total LULCC radiative forcing by a factor of 2 to 3 with respect to the forcing from CO2 alone. In contrast, the non-CO2 forcings from fossil fuel burning are roughly neutral, due largely to the negative (cooling) impact of aerosols from these sources. We partition the global LULCC radiative forcing into three major sources: direct modification of land cover (e.g. deforestation), agricultural activities, and fire regime changes. Contributions from deforestation and agriculture are roughly equal in the present day, while changes to wildfire activity impose a small negative forcing globally. In 2100, deforestation activities comprise the majority of the LULCC radiative forcing for all projections except one (Representative Concentration Pathway (RCP) 4.5). This suggests that realistic scenarios of future forest area change are essential for projecting the contribution of LULCC to climate change. However, the commonly used RCP land cover change projections all include decreases in global deforestation rates over the next 85 years. To place an upper bound on the potential radiative forcing from LULCC we create a 'worst-case scenario" in which all arable land is converted to agriculture by the year 2100. This scenario leads to a total radiative forcing of 4.3 Wm-2 (+/- 1 Wm-2) suggesting that well thought-out land policy is needed to minimize future increases in global anthropogenic radiative forcing.

10 CFR 835.101 - Radiation protection programs.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 4 2011-01-01 2011-01-01 false Radiation protection programs. 835.101 Section 835.101 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Management and Administrative Requirements § 835.101 Radiation protection programs. (a) A DOE activity shall be conducted in compliance with a...

10 CFR 835.101 - Radiation protection programs.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 4 2012-01-01 2012-01-01 false Radiation protection programs. 835.101 Section 835.101 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Management and Administrative Requirements § 835.101 Radiation protection programs. (a) A DOE activity shall be conducted in compliance with a...

10 CFR 835.101 - Radiation protection programs.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 4 2013-01-01 2013-01-01 false Radiation protection programs. 835.101 Section 835.101 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Management and Administrative Requirements § 835.101 Radiation protection programs. (a) A DOE activity shall be conducted in compliance with a...

10 CFR 835.101 - Radiation protection programs.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 4 2010-01-01 2010-01-01 false Radiation protection programs. 835.101 Section 835.101 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Management and Administrative Requirements § 835.101 Radiation protection programs. (a) A DOE activity shall be conducted in compliance with a...

10 CFR 835.101 - Radiation protection programs.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 4 2014-01-01 2014-01-01 false Radiation protection programs. 835.101 Section 835.101 Energy DEPARTMENT OF ENERGY OCCUPATIONAL RADIATION PROTECTION Management and Administrative Requirements § 835.101 Radiation protection programs. (a) A DOE activity shall be conducted in compliance with a...

29 CFR 1926.53 - Ionizing radiation.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 29 Labor 8 2011-07-01 2011-07-01 false Ionizing radiation. 1926.53 Section 1926.53 Labor... § 1926.53 Ionizing radiation. (a) In construction and related activities involving the use of sources of ionizing radiation, the pertinent provisions of the Nuclear Regulatory Commission's Standards for...

29 CFR 1926.53 - Ionizing radiation.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 29 Labor 8 2012-07-01 2012-07-01 false Ionizing radiation. 1926.53 Section 1926.53 Labor... § 1926.53 Ionizing radiation. (a) In construction and related activities involving the use of sources of ionizing radiation, the pertinent provisions of the Nuclear Regulatory Commission's Standards for...

29 CFR 1926.53 - Ionizing radiation.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 29 Labor 8 2014-07-01 2014-07-01 false Ionizing radiation. 1926.53 Section 1926.53 Labor... § 1926.53 Ionizing radiation. (a) In construction and related activities involving the use of sources of ionizing radiation, the pertinent provisions of the Nuclear Regulatory Commission's Standards for...

EVALUATION OF SIGNIFICANT ANTHROPOGENIC SOURCES OF RADIATIVELY IMPORTANT TRACE GASES

EPA Science Inventory

The report is an initial evaluation of significant anthropogenic sources of radiatively important trace gases. missions of greenhouse gases from human activities--including fossil fuel combustion, industrial/agricultural activities, and transportation--contribute to the increasin...

Overview of active methods for shielding spacecraft from energetic space radiation

NASA Technical Reports Server (NTRS)

Townsend, L. W.; Wilson, J. W. (Principal Investigator)

2001-01-01

During the 1960's and into the early 1970's, investigations were conducted related to the feasibility of using active radiation shielding methods, such as afforded by electromagnetic fields, as alternatives to passive, bulk material shielding to attenuate space radiations. These active concepts fall into four categories: (1) electrostatic fields; (2) plasma shields; (3) confined magnetic fields; and (4) unconfined magnetic fields. In nearly all of these investigations, consideration was given only to shielding against protons or electrons, or both. During the 1980's and 1990's there were additional studies related to proton shielding and some new studies regarding the efficacy of using active methods to shield from the high energy heavy ion (HZE particle) component of the galactic cosmic ray spectrum. In this overview, each concept category is reviewed and its applicability and limitations for the various types of space radiations are described. Recommendations for future research on this topic are made.

Active/Passive Control of Sound Radiation from Panels using Constrained Layer Damping

NASA Technical Reports Server (NTRS)

Gibbs, Gary P.; Cabell, Randolph H.

2003-01-01

A hybrid passive/active noise control system utilizing constrained layer damping and model predictive feedback control is presented. This system is used to control the sound radiation of panels due to broadband disturbances. To facilitate the hybrid system design, a methodology for placement of constrained layer damping which targets selected modes based on their relative radiated sound power is developed. The placement methodology is utilized to determine two constrained layer damping configurations for experimental evaluation of a hybrid system. The first configuration targets the (4,1) panel mode which is not controllable by the piezoelectric control actuator, and the (2,3) and (5,2) panel modes. The second configuration targets the (1,1) and (3,1) modes. The experimental results demonstrate the improved reduction of radiated sound power using the hybrid passive/active control system as compared to the active control system alone.

Up-stream events in the nuclear factor κB activation cascade in response to sparsely ionizing radiation

NASA Astrophysics Data System (ADS)

Hellweg, Christine E.; Langen, Britta; Klimow, Galina; Ruscher, Roland; Schmitz, Claudia; Baumstark-Khan, Christa; Reitz, Günther

2009-10-01

Radiation is a potentially limiting factor for manned long-term space missions. Prolonged exposure to galactic cosmic rays may shorten the healthy life-span after return to Earth due to cancer induction. During the mission, a solar flare can be life threatening. For better risk estimation and development of appropriate countermeasures, the study of the cellular radiation response is necessary. Since apoptosis may be a mechanism the body uses to eliminate damaged cells, the induction by cosmic radiation of the nuclear anti-apoptotic transcription factor nuclear factor κB (NF-κB) could influence the cancer risk of astronauts exposed to cosmic radiation by improving the survival of radiation-damaged cells. In previous studies using a screening assay for the detection of NF-κB-dependent gene induction (HEK-pNF-κB-d2EGFP/Neo cells), the activation of this transcription factor by heavy ions was shown [Baumstark-Khan, C., Hellweg, C.E., Arenz, A., Meier, M.M. Cellular monitoring of the nuclear factor kappa B pathway for assessment of space environmental radiation. Radiat. Res. 164, 527-530, 2005]. Studies with NF-κB inhibitors can map functional details of the NF-κB pathway and the influence of radiation-induced NF-κB activation on various cellular outcomes such as survival or cell cycle arrest. In this work, the efficacy and cytotoxicity of four different NF-κB inhibitors, caffeic acid phenethyl ester (CAPE), capsaicin, the proteasome inhibitor MG-132, and the cell permeable peptide NF-κB SN50 were analyzed using HEK-pNF-κB-d2EGFP/Neo cells. In the recommended concentration range, only CAPE displayed considerable cytotoxicity. CAPE and capsaicin partially inhibited NF-κB activation by the cytokine tumor necrosis factor α. MG-132 completely abolished the activation and was therefore used for experiments with X-rays. NF-κB SN-50 could not reduce NF-κB dependent expression of the reporter destabilized Enhanced Green Fluorescent Protein (d2EGFP). MG-132 entirely suppressed the X-ray induced NF-κB activation in HEK-pNF-κB-d2EGFP/Neo cells. In conclusion, the degradation of the inhibitor of NF-κB (IκB) in the proteasome is essential for X-ray induced NF-κB activation, and MG-132 will be useful in studies of the NF-κB pathway involvement in the cellular response to heavy ion exposure and other space-relevant radiation qualities.

Combined Release and Radiation Effects Satellite (CRRES) experiments data collection, analysis, and publication

NASA Technical Reports Server (NTRS)

Long, Terry N.; Alzmann, Melanie O.

1992-01-01

The Combined Release and Radiation Effects Satellite (CRRES) program experiments data collection, analysis, and publication activities are described. These activities were associated with both the satellite chemical release and a planned Puerto Rico sounding rocket campaign. To coordinate these activities, a working group meeting was organized and conducted.

National Marrow Donor Program

DTIC Science & Technology

2011-04-29

Radiation D O) rugs http://www.nytimes.com/2011/04/01/ business /01radiation.html?_r=1 3/29/2011-Amid Japan crisis, hunt for better radiation...activity this quarter. IIA.3 Task 2: Critical Fac ility and Staff Related Functions Period 4 Activity: Conducted a Business Continuity Plan (BCP...of 21 the and review and determination of future projects to close these gaps. Began preparing Business Continuity Plan Exercise 2011 (BCPeX 2011

Effects of low-intensity ultrahigh frequency electromagnetic radiation on inflammatory processes.

PubMed

Lushnikov, K V; Shumilina, Yu V; Yakushina, V S; Gapeev, A B; Sadovnikov, V B; Chemeris, N K

2004-04-01

Low-intensity ultrahigh frequency electromagnetic radiation (42 GHz, 100 microW/cm(2)) reduces the severity of inflammation and inhibits production of active oxygen forms by inflammatory exudate neutrophils only in mice with inflammatory process. These data suggest that some therapeutic effects of electromagnetic radiation can be explained by its antiinflammatory effect which is realized via modulation of functional activity of neutrophils in the focus of inflammation.

Lévy noise improves the electrical activity in a neuron under electromagnetic radiation.

PubMed

Wu, Juan; Xu, Yong; Ma, Jun

2017-01-01

As the fluctuations of the internal bioelectricity of nervous system is various and complex, the external electromagnetic radiation induced by magnet flux on membrane can be described by the non-Gaussian type distribution of Lévy noise. Thus, the electrical activities in an improved Hindmarsh-Rose model excited by the external electromagnetic radiation of Lévy noise are investigated and some interesting modes of the electrical activities are exhibited. The external electromagnetic radiation of Lévy noise leads to the mode transition of the electrical activities and spatial phase, such as from the rest state to the firing state, from the spiking state to the spiking state with more spikes, and from the spiking state to the bursting state. Then the time points of the firing state versus Lévy noise intensity are depicted. The increasing of Lévy noise intensity heightens the neuron firing. Also the stationary probability distribution functions of the membrane potential of the neuron induced by the external electromagnetic radiation of Lévy noise with different intensity, stability index and skewness papremeters are analyzed. Moreover, through the positive largest Lyapunov exponent, the parameter regions of chaotic electrical mode of the neuron induced by the external electromagnetic radiation of Lévy noise distribution are detected.

Lévy noise improves the electrical activity in a neuron under electromagnetic radiation

PubMed Central

Wu, Juan; Ma, Jun

2017-01-01

As the fluctuations of the internal bioelectricity of nervous system is various and complex, the external electromagnetic radiation induced by magnet flux on membrane can be described by the non-Gaussian type distribution of Lévy noise. Thus, the electrical activities in an improved Hindmarsh-Rose model excited by the external electromagnetic radiation of Lévy noise are investigated and some interesting modes of the electrical activities are exhibited. The external electromagnetic radiation of Lévy noise leads to the mode transition of the electrical activities and spatial phase, such as from the rest state to the firing state, from the spiking state to the spiking state with more spikes, and from the spiking state to the bursting state. Then the time points of the firing state versus Lévy noise intensity are depicted. The increasing of Lévy noise intensity heightens the neuron firing. Also the stationary probability distribution functions of the membrane potential of the neuron induced by the external electromagnetic radiation of Lévy noise with different intensity, stability index and skewness papremeters are analyzed. Moreover, through the positive largest Lyapunov exponent, the parameter regions of chaotic electrical mode of the neuron induced by the external electromagnetic radiation of Lévy noise distribution are detected. PMID:28358824

Radiation activated CHK1/MEPE pathway may contribute to microgravity-induced bone density loss

NASA Astrophysics Data System (ADS)

Zhang, Xiangming; Wang, Ping; Wang, Ya

2015-11-01

Bone density loss in astronauts on long-term space missions is a chief medical concern. Microgravity in space is the major cause of bone density loss (osteopenia), and it is believed that high linear energy transfer (LET) radiation in space exacerbates microgravity-induced bone density loss; however, the mechanism remains unclear. It is known that acidic serine- and aspartate-rich motif (ASARM) as a small peptide released by matrix extracellular phosphoglycoprotein (MEPE) promotes osteopenia. We previously discovered that MEPE interacted with checkpoint kinase 1 (CHK1) to protect CHK1 from ionizing radiation promoted degradation. In this study, we addressed whether the CHK1-MEPE pathway activated by radiation contributes to the effects of microgravity on bone density loss. We examined the CHK1, MEPE and secreted MEPE/ASARM levels in irradiated (1 Gy of X-ray) and rotated cultured human osteoblast cells. The results showed that radiation activated CHK1, decreased the levels of CHK1 and MEPE in human osteoblast cells and increased the release of MEPE/ASARM. These results suggest that the radiation-activated CHK1/MEPE pathway exacerbates the effects of microgravity on bone density loss, which may provide a novel targeting factor/pathway for a future countermeasure design that could contribute to reducing osteopenia in astronauts.

[Staffing levels in medical radiation physics in radiation therapy in Germany. Summary of a questionnaire].

PubMed

Leetz, Hans-Karl; Eipper, Hermann Hans; Gfirtner, Hans; Schneider, Peter; Welker, Klaus

2003-10-01

To get a general idea of the actual staffing level situation in medical radiation physics in 1999 a survey was carried out by the task-group "Personalbedarf" of Deutsche Gesellschaft für Medizinische Physik (DGMP) among all DGMP-members who are active in this field. Main components for equipment and activities are defined in Report 8 and 10 of DGMP for staffing requirements in medical radiation physics. 322 forms were sent out, 173 of them have been evaluated. From the answers regarding equipment and activities numbers for staff are calculated by the methods given in Report 8 and 10 for this spot check target and compared with effective staffing levels. The data of the spot check are then extrapolated on total Germany. The result is a calculated deficit of 865 medical physicists for the whole physics staff, 166 of them in radiation therapy. From the age distribution of DGMP-members and the calculated deficit resulted a training capacity of about 100 medical physicists at all per year (19 in radiation therapy) if the deficit shall be cut back in 10 years.

An analytical and experimental investigation of active structural acoustic control of noise transmission through double panel systems

NASA Astrophysics Data System (ADS)

Carneal, James P.; Fuller, Chris R.

2004-05-01

An analytical and experimental investigation of active control of sound transmission through double panel systems has been performed. The technique used was active structural acoustic control (ASAC) where the control inputs, in the form of piezoelectric actuators, were applied to the structure while the radiating pressure field was minimized. Results verify earlier experimental investigations and indicate the application of control inputs to the radiating panel of the double panel system resulted in greater transmission loss (TL) due to its direct effect on the nature of the structural-acoustic (or radiation) coupling between the radiating panel and the receiving acoustic space. Increased control performance was seen in a double panel system consisting of a stiffer radiating panel due to its lower modal density and also as a result of better impedance matching between the piezoelectric actuator and the radiating plate. In general the results validate the ASAC approach for double panel systems, demonstrating that it is possible to take advantage of double panel system passive behavior to enhance control performance, and provide design guidelines.

Physical and biological properties of U. S. standard endotoxin EC after exposure to ionizing radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Csako, G.; Elin, R.J.; Hochstein, H.D.

Techniques that reduce the toxicity of bacterial endotoxins are useful for studying the relationship between structure and biological activity. We used ionizing radiation to detoxify a highly refined endotoxin preparation. U.S. standard endotoxin EC. Dose-dependent changes occurred by exposure to /sup 60/Co-radiation in the physical properties and biological activities of the endotoxin. Sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis showed gradual loss of the polysaccharide components (O-side chain and R-core) from the endotoxin molecules. In contrast, although endotoxin revealed a complex absorption pattern in the UV range, radiation treatment failed to modify that pattern. Dose-related destruction of the primary toxic component,more » lipid A, was suggested by the results of activity tests: both the pyrogenicity and limulus reactivity of the endotoxin were destroyed by increasing doses of radiation. The results indicate that the detoxification is probably due to multiple effects of the ionizing radiation on bacterial lipopolysaccharides, and the action involves (i) the destruction of polysaccharide moieties and possibly (ii) the alteration of lipid A component of the endotoxin molecule.« less

Assessment of radiation awareness training in immersive virtual environments

NASA Astrophysics Data System (ADS)

Whisker, Vaughn E., III

The prospect of new nuclear power plant orders in the near future and the graying of the current workforce create a need to train new personnel faster and better. Immersive virtual reality (VR) may offer a solution to the training challenge. VR technology presented in a CAVE Automatic Virtual Environment (CAVE) provides a high-fidelity, one-to-one scale environment where areas of the power plant can be recreated and virtual radiation environments can be simulated, making it possible to safely expose workers to virtual radiation in the context of the actual work environment. The use of virtual reality for training is supported by many educational theories; constructivism and discovery learning, in particular. Educational theory describes the importance of matching the training to the task. Plant access training and radiation worker training, common forms of training in the nuclear industry, rely on computer-based training methods in most cases, which effectively transfer declarative knowledge, but are poor at transferring skills. If an activity were to be added, the training would provide personnel with the opportunity to develop skills and apply their knowledge so they could be more effective when working in the radiation environment. An experiment was developed to test immersive virtual reality's suitability for training radiation awareness. Using a mixed methodology of quantitative and qualitative measures, the subjects' performances before and after training were assessed. First, subjects completed a pre-test to measure their knowledge prior to completing any training. Next they completed unsupervised computer-based training, which consisted of a PowerPoint presentation and a PDF document. After completing a brief orientation activity in the virtual environment, one group of participants received supplemental radiation awareness training in a simulated radiation environment presented in the CAVE, while a second group, the control group, moved directly to the assessment phase of the experiment. The CAVE supplied an activity-based training environment where learners were able to use a virtual survey meter to explore the properties of radiation sources and the effects of time and distance on radiation exposure. Once the training stage had ended, the subjects completed an assessment activity where they were asked to complete four tasks in a simulated radiation environment in the CAVE, which was designed to provide a more authentic assessment than simply testing understanding using a quiz. After the practicum, the subjects completed a post-test. Survey information was also collected to assist the researcher with interpretation of the collected data. Response to the training was measured by completion time, radiation exposure received, successful completion of the four tasks in the practicum, and scores on the post-test. These results were combined to create a radiation awareness score. In addition, observational data was collected as the subjects completed the tasks. The radiation awareness scores of the control group and the group that received supplemental training in the virtual environment were compared. T-tests showed that the effect of the supplemental training was not significant; however, calculation of the effect size showed a small-to-medium effect of the training. The CAVE group received significantly less radiation exposure during the assessment activity, and they completed the activities on an average of one minute faster. These results indicate that the training was effective, primarily for instilling radiation sensitivity. Observational data collected during the assessment supports this conclusion. The training environment provided by the immersive virtual reality recreated a radiation environment where learners could apply knowledge they had been taught by computer-based training. Activity-based training has been shown to be a more effective way to transfer skills because of the similarity between the training environment and the application environment. Virtual reality enables the training environment to look and feel like the application environment. Because of this, radiation awareness training in an immersive virtual environment should be considered by the nuclear industry, which is supported by the results of this experiment.

NF-kB activation and its downstream target genes expression after heavy ions exposure

NASA Astrophysics Data System (ADS)

Chishti, Arif Ali; Baumstark-Khan, Christa; Hellweg, Christine; Schmitz, Claudia; Koch, Kristina; Feles, Sebastian

2016-07-01

To enable long-term human space flight cellular radiation response to densely ionizing radiation needs to be better understood for developing appropriate countermeasures to mitigate acute effects and late radiation risks for the astronaut. The biological effectiveness of accelerated heavy ions (which constitute the most important radiation type in space) with high linear energy transfer (LET) for effecting DNA damage response pathways as a gateway to cell death or survival is of major concern not only for space missions but also for new regimes of tumor radiotherapy. In the current research study, the contribution of NF-κB in response to space-relevant radiation qualities was determined by a NF-κB reporter cell line (HEK-pNF-κB-d2EGFP/Neo L2). The NF-κB dependent reporter gene expression (d2EGFP) after ionizing radiation (X-rays and heavy ions) exposure was evaluated by flow cytometry. Because of differences in the extent of NF-κB activation after X-irradiation and heavy ions exposure, it was expected that radiation quality (LET) might play an important role in the cellular radiation response. In addition, the biological effectiveness (RBE) of NF-κB activation and reduction of cellular survival was examined for heavy ions having a broad range of LET (˜0.3 - 9674 keV/µm). Furthermore, the effect of LET on NF-κB target gene expression was analyzed by real time reverse transcriptase quantitative PCR (RT-qPCR). In this study it was proven that NF-κB activation and NF-κB dependent gene expression comprises an early step in cellular radiation response. Taken together, this study clearly demonstrates that NF-κB activation and NF-κB-dependent gene expression by heavy ions are highest in the LET range of ˜50-200 keV/μupm. The up-regulated chemokines and cytokines (CXCL1, CXCL2, CXCL10, IL-8 and TNF) might be important for cell-cell communication among hit as well as unhit cells (bystander effect). The results obtained suggest the NF-κB pathway to be a promising target for pharmacological modulation of cellular radiation response either to improve tumor cell killing during radiotherapy with heavy ions or to mitigate radiation late effects in astronauts or irradiated healthy tissue.

Radiation-Hardened Electronics for the Space Environment

NASA Technical Reports Server (NTRS)

Keys, Andrew S.; Watson, Michael D.

2007-01-01

RHESE covers a broad range of technology areas and products. - Radiation Hardened Electronics - High Performance Processing - Reconfigurable Computing - Radiation Environmental Effects Modeling - Low Temperature Radiation Hardened Electronics. RHESE has aligned with currently defined customer needs. RHESE is leveraging/advancing SOA space electronics, not duplicating. - Awareness of radiation-related activities through out government and industry allow advancement rather than duplication of capabilities.

Use of Combination Thermal Therapy and Radiation in Breast-Conserving Treatment of Extensive Intraductal Breast Cancer

DTIC Science & Technology

1997-07-01

Review Board of the DFCI is provided in Appendix A . The investigator will keep the following information on each patient: 1. Past medical ...treatments, you will receive radiation therapy to your breast. Your radiation oncologist will decide what radiation dose you receive . On the basis of... Activities 6/87 Controversies in radiation therapy in

Multidisciplinary European Low Dose Initiative (MELODI): strategic research agenda for low dose radiation risk research.

PubMed

Kreuzer, M; Auvinen, A; Cardis, E; Durante, M; Harms-Ringdahl, M; Jourdain, J R; Madas, B G; Ottolenghi, A; Pazzaglia, S; Prise, K M; Quintens, R; Sabatier, L; Bouffler, S

2018-03-01

MELODI (Multidisciplinary European Low Dose Initiative) is a European radiation protection research platform with focus on research on health risks after exposure to low-dose ionising radiation. It was founded in 2010 and currently includes 44 members from 18 countries. A major activity of MELODI is the continuous development of a long-term European Strategic Research Agenda (SRA) on low-dose risk for radiation protection. The SRA is intended to identify priorities for national and European radiation protection research programs as a basis for the preparation of competitive calls at the European level. Among those key priorities is the improvement of health risk estimates for exposures close to the dose limits for workers and to reference levels for the population in emergency situations. Another activity of MELODI is to ensure the availability of European key infrastructures for research activities, and the long-term maintenance of competences in radiation research via an integrated European approach for training and education. The MELODI SRA identifies three key research topics in low dose or low dose-rate radiation risk research: (1) dose and dose rate dependence of cancer risk, (2) radiation-induced non-cancer effects and (3) individual radiation sensitivity. The research required to improve the evidence base for each of the three key topics relates to three research lines: (1) research to improve understanding of the mechanisms contributing to radiogenic diseases, (2) epidemiological research to improve health risk evaluation of radiation exposure and (3) research to address the effects and risks associated with internal exposures, differing radiation qualities and inhomogeneous exposures. The full SRA and associated documents can be downloaded from the MELODI website ( http://www.melodi-online.eu/sra.html ).

Insulin-Like Growth Factor-1 Preserves Salivary Gland Function After Fractionated Radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Limesand, Kirsten H., E-mail: limesank@u.arizona.ed; Department of Nutritional Sciences, University of Arizona, Tucson, AZ; Avila, Jennifer L.

Purpose: Radiotherapy for head-and-neck cancer consists of fractionated radiation treatments that cause significant damage to salivary glands leading to chronic salivary gland dysfunction with only limited prevention and treatment options currently available. This study examines the feasibility of IGF-1 in preserving salivary gland function following a fractionated radiation treatment regimen in a pre-clinical model. Methods and Materials: Mice were exposed to fractionated radiation, and salivary gland function and histological analyses of structure, apoptosis, and proliferation were evaluated. Results: In this study, we report that treatment with fractionated doses of radiation results in a significant level of apoptotic cells in FVBmore » mice after each fraction, which is significantly decreased in transgenic mice expressing a constitutively active mutant of Akt1 (myr-Akt1). Salivary gland function is significantly reduced in FVB mice exposed to fractionated radiation; however, myr-Akt1 transgenic mice maintain salivary function under the same treatment conditions. Injection into FVB mice of recombinant insulin-like growth factor-1 (IGF-1), which activates endogenous Akt, suppressed acute apoptosis and preserved salivary gland function after fractionated doses of radiation 30 to 90 days after treatment. FVB mice exposed to fractionated radiation had significantly lower levels of proliferating cell nuclear antigen-positive salivary acinar cells 90 days after treatment, which correlated with a chronic loss of function. In contrast, FVB mice injected with IGF-1 before each radiation treatment exhibited acinar cell proliferation rates similar to those of untreated controls. Conclusion: These studies suggest that activation of IGF-1-mediated pathways before head-and-neck radiation could modulate radiation-induced salivary gland dysfunction and maintain glandular homeostasis.« less

Protective role of hesperidin against γ-radiation-induced oxidative stress and apoptosis in rat testis.

PubMed

Shaban, Nadia Z; Ahmed Zahran, Ahmed M; El-Rashidy, Fatma H; Abdo Kodous, Ahmad S

2017-12-01

Gamma (γ) ray, an electromagnetic radiation, is occasionally accompanying the emission of an alpha or beta particle. Exposure to such radiation can cause cellular changes such as mutations, chromosome aberration and cellular damage which depend upon the total amount of energy, duration of exposure and the dose. Ionizing radiation can impair spermatogenesis and can cause mutations in germ cells. In general, type B spermatogonia are sensitive to this type of radiation. The current study was carried out to evaluate the protective role of hesperidin (H), as a polyphenolic compound, on rat testis injury induced by γ-radiation. Rats were divided into groups including C group (control rats), R (irradiated) group (rats irradiated with γ-radiation), Vehicle (V) group (rats administered with dimethylsulfoxide "DMSO"), H group (rats administered with H only), HR and RH groups (rats treated with H before and after exposure to γ-radiation, respectively). Malondialdehyde (MDA: the end product of lipid peroxidation "LPO") and xanthine oxidase (XO: it generates reactive oxygen species "ROS") in testes homogenate as well as nitric oxide (NO: as ROS) in mitochondrial matrix were determined. The apoptotic markers including DNA-fragmentation (DNAF) in testes homogenate and calcium ions (Ca 2+ ) in mitochondrial matrix were determined. Superoxide dismutase (SOD) and catalase (CAT) activities in testes homogenate, while reduced glutathione "GSH" in nuclear matrix were determined. Also histopathological examination for testes tissues through electron microscope was studied. Exposure of rats to γ-radiation (R group) increased the levels of MDA, NO, DNAF, Ca 2+ and XO activity, while it decreased GSH level, SOD and CAT activities as compared to the C groups; γ-radiation increased oxidative stress (OS), LPO, apoptosis and induced testes injuries. These results are in agreement with the histopathological examination. In contrast, treatment with H before or after exposure to γ-radiation (HR and RH groups, respectively) decreased the levels of MDA, NO, DNAF and Ca 2+ but increased GSH level and the activities of SOD, CAT and XO as compared to R group and this indicates that H decreased OS, LPO and apoptosis. Also, the histopathological results showed that H improved testis architecture and this is related to the antioxidant and anti-apoptotic activities of H contents. Protection is more effective when H is given before rather than after exposure. Finally, administration of H to healthy rats for a short period had no adverse affect on testes cells. Hesperidin showed antioxidant and anti-apoptotic activities. It has a protective role against OS, injury and apoptosis induced by γ-radiation in testes. Protection is more effective when H is given before rather than after exposure.Graphical Abstract.

Combined effects of lanthanum(III) and elevated ultraviolet-B radiation on root growth and ion absorption in soybean seedlings.

PubMed

Huang, Guang Rong; Wang, Li Hong; Zhou, Qing

2014-03-01

Rare earth element accumulation in the soil and elevated ultraviolet (UV)-B radiation (280-315 nm) are important environmental issues worldwide. To date, there have been no reports concerning the combined effects of lanthanum (La)(III) and elevated UV-B radiation on plant roots in regions where the two issues occur simultaneously. Here, the combined effects of La(III) and elevated UV-B radiation on the growth, biomass, ion absorption, activities, and membrane permeability of roots in soybean (Glycine max L.) seedlings were investigated. A 0.08 mmol L(-1) La(III) treatment improved the root growth and biomass of soybean seedlings, while ion absorption, activities, and membrane permeability were obviously unchanged; a combined treatment with 0.08 mmol L(-1) La(III) and elevated UV-B radiation (2.63/6.17 kJ m(-2) day(-1)) exerted deleterious effects on the investigated indices. The deleterious effects were aggravated in the other combined treatments and were stronger than those of treatments with La(III) or elevated UV-B radiation alone. The combined treatment with 0.24/1.20 mmol L(-1) La(III) and elevated UV-B radiation exerted synergistically deleterious effects on the growth, biomass, ion absorption, activities, and membrane permeability of roots in soybean seedlings. In addition, the deleterious effects of the combined treatment on the root growth were due to the inhibition of ion absorption induced by the changes in the root activity and membrane permeability.

[The activity of prooxidant-antioxidant system in loach embryos under the action of microwave radiation].

PubMed

Iaremchuk, M M; Dyka, M V; Sanahurs'kyĭ, D I

2014-01-01

Electromagnetic radiation (EMR) affects biological organisms, primarily on the cellular level. However, the effects of EMR at low-intensity exposure on animals and state of metabolic systems are not fully defined yet. Thus, research of microwave radiation influence on the processes of lipid peroxidation and antioxidant protection system is important for understanding the mechanisms of EMR action on the cell, in particular, and organism development on the whole. The content of lipid peroxidation products--lipid hydroperoxides, thiobarbituric acid reactive substances and the activity of antioxidant enzymes--superoxide dismutase, glutathione peroxidase and catalase in loach embryos under the action of microwave radiation (GSM-900 MHz, SAR = 1.1 Vt/kg) lasting 1; 5; 10 and 20 min during early embryogenesis were studied. It has been found that content of lipid peroxidation products in germ cells undergoes significant changes under the action of low-intensity EMR. The effect of microwave radiation (1, 5, 10 min) leads to the increase of superoxide dismutase activity, nevertheless, 20 min exposure decreased this index to the level of control values as it is shown. It has been established that EMR at frequencies used for mobile communications reduce the activity of antioxidant protection system components, especially catalase and glutathione peroxidase. The growth of catalase activity at the 10-cell stage of blastomere division (P < 0.05) is an exception. The results of two-way analysis of variance attest that microwave radiation factor causes the large part of all observable modifications.

Indirect macrophage responses to ionizing radiation: implications for genotype-dependent bystander signaling.

PubMed

Coates, Philip J; Rundle, Jana K; Lorimore, Sally A; Wright, Eric G

2008-01-15

In addition to the directly mutagenic effects of energy deposition in DNA, ionizing radiation is associated with a variety of untargeted and delayed effects that result in ongoing bone marrow damage. Delayed effects are genotype dependent with CBA/Ca mice, but not C57BL/6 mice, susceptible to the induction of damage and also radiation-induced acute myeloid leukemia. Because macrophages are a potential source of ongoing damaging signals, we have determined their gene expression profiles and we show that bone marrow-derived macrophages show widely different intrinsic expression patterns. The profiles classify macrophages derived from CBA/Ca mice as M1-like (pro-inflammatory) and those from C57BL/6 mice as M2-like (anti-inflammatory); measurements of NOS2 and arginase activity in normal bone marrow macrophages confirm these findings. After irradiation in vivo, but not in vitro, C57BL/6 macrophages show a reduction in NOS2 and an increase in arginase activities, indicating a further M2 response, whereas CBA/Ca macrophages retain an M1 phenotype. Activation of specific signal transducer and activator of transcription signaling pathways in irradiated hemopoietic tissues supports these observations. The data indicate that macrophage activation is not a direct effect of radiation but a tissue response, secondary to the initial radiation exposure, and have important implications for understanding genotype-dependent responses and the mechanisms of the hemotoxic and leukemogenic consequences of radiation exposure.

Effect of 99 GHz continuous millimeter wave electro-magnetic radiation on E. coli viability and metabolic activity.

PubMed

Cohen, Irena; Cahan, Rivka; Shani, Gad; Cohen, Eyal; Abramovich, Amir

2010-05-01

To investigate time exposure dependence of continuous millimeter wave (CW) 99 GHz radiation on Escherichia coli bacterial cell viability and metabolic activity. Suspensions of E. coli bacterial cells with an optical density of OD(660 nm) = 0.1 were used for viability tests and OD(660 nm) = 1.0 for metabolic activity tests. These suspensions were exposed to 99 GHz CW electromagnetic radiation, generated by a Backward Wave Oscillator (BWO) tube base instrument with a horn antenna at the BWO exit, to obtain an almost ideal Gaussian beam. Calculations of the Gaussian beam show that a power of 0.2 mW/cm(2) was obtained at the bacterial plane. The experimental results show that 1 hour of exposure to 99 GHz CW electromagnetic radiation had no effect on E. coli viability and colony characterisation. In 19 h of radiation, the number of colonies forming units was half order of magnitude higher than the sham-exposed and the control. However, 19 h of exposure did not affect the E. coli metabolic activity. Exposure of E. coli to millimeter wave (MW) CW 99 GHz radiation for a short period did not affect the viability of E. coli bacterial cells. However, exposure for 19 h caused a slight proliferation but did not influence the metabolic activities of about 90 biochemical reactions that were examined. Hence, we assume that the slight proliferation (half order of magnitude) after 19 h of exposure dose not have a biological meaning.

Radiation Hard Active Media R&D for CMS Hadron Endcap Calorimetry

NASA Astrophysics Data System (ADS)

Tiras, Emrah; CMS-HCAL Collaboration

2015-04-01

The High Luminosity LHC era imposes unprecedented radiation conditions on the CMS detectors targeting a factor of 5-10 higher than the LHC design luminosity. The CMS detectors will need to be upgraded in order to withstand these conditions yet maintain/improve the physics measurement capabilities. One of the upgrade options is reconstructing the CMS Endcap Calorimeters with a shashlik design electromagnetic section and replacing active media of the hadronic section with radiation-hard scintillation materials. In this context, we have studied various radiation-hard materials such as Polyethylene Naphthalate (PEN), Polyethylene Terephthalate (PET), HEM and quartz plates coated with various organic materials such as p-Terphenyl (pTp), Gallium doped Zinc Oxide (ZnO:Ga) and Anthracene. Here we discuss the related test beam activities, laboratory measurements and recent developments.

Radiosensitivity profiles from a panel of ovarian cancer cell lines exhibiting genetic alterations in p53 and disparate DNA-dependent protein kinase activities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Langland, Gregory T.; Yannone, Steven M.; Langland, Rachel A.

2009-09-07

The variability of radiation responses in ovarian tumors and tumor-derived cell lines is poorly understood. Since both DNA repair capacity and p53 status can significantly alter radiation sensitivity, we evaluated these factors along with radiation sensitivity in a panel of sporadic human ovarian carcinoma cell lines. We observed a gradation of radiation sensitivity among these sixteen lines, with a five-fold difference in the LD50 between the most radiosensitive and the most radioresistant cells. The DNA-dependent protein kinase (DNA-PK) is essential for the repair of radiation induced DNA double-strand breaks in human somatic cells. Therefore, we measured gene copy number, expressionmore » levels, protein abundance, genomic copy and kinase activity for DNA-PK in all of our cell lines. While there were detectable differences in DNA-PK between the cell lines, there was no clear correlation with any of these differences and radiation sensitivity. In contrast, p53 function as determined by two independent methods, correlated well with radiation sensitivity, indicating p53 mutant ovarian cancer cells are typically radioresistant relative to p53 wild-type lines. These data suggest that the activity of regulatory molecules such as p53 may be better indicators of radiation sensitivity than DNA repair enzymes such as DNAPK in ovarian cancer.« less

Advances in Atmospheric Radiation Measurements and Modeling Needed to Improve Air Safety

NASA Astrophysics Data System (ADS)

Tobiska, W. Kent; Atwell, William; Beck, Peter; Benton, Eric; Copeland, Kyle; Dyer, Clive; Gersey, Brad; Getley, Ian; Hands, Alex; Holland, Michael; Hong, Sunhak; Hwang, Junga; Jones, Bryn; Malone, Kathleen; Meier, Matthias M.; Mertens, Chris; Phillips, Tony; Ryden, Keith; Schwadron, Nathan; Wender, Stephen A.; Wilkins, Richard; Xapsos, Michael A.

2015-04-01

Air safety is tied to the phenomenon of ionizing radiation from space weather, primarily from galactic cosmic rays but also from solar energetic particles. A global framework for addressing radiation issues in this environment has been constructed, but more must be done at international and national levels. Health consequences from atmospheric radiation exposure are likely to exist. In addition, severe solar radiation events may cause economic consequences in the international aviation community due to exposure limits being reached by some crew members. Impacts from a radiation environment upon avionics from high-energy particles and low-energy, thermalized neutrons are now recognized as an area of active interest. A broad community recognizes that there are a number of mitigation paths that can be taken relative to the human tissue and avionics exposure risks. These include developing active monitoring and measurement programs as well as improving scientific modeling capabilities that can eventually be turned into operations. A number of roadblocks to risk mitigation still exist, such as effective pilot training programs as well as monitoring, measuring, and regulatory measures. An active international effort toward observing the weather of atmospheric radiation must occur to make progress in mitigating radiation exposure risks. Stakeholders in this process include standard-making bodies, scientific organizations, regulatory organizations, air traffic management systems, aircraft owners and operators, pilots and crew, and even the public.

The Role of Radiation Pressure in the Narrow Line Regions of Seyfert Host Galaxies

NASA Astrophysics Data System (ADS)

Davies, Rebecca L.; Dopita, Michael A.; Kewley, Lisa; Groves, Brent; Sutherland, Ralph; Hampton, Elise J.; Shastri, Prajval; Kharb, Preeti; Bhatt, Harish; Scharwächter, Julia; Jin, Chichuan; Banfield, Julie; Zaw, Ingyin; James, Bethan; Juneau, Stéphanie; Srivastava, Shweta

2016-06-01

We investigate the relative significance of radiation pressure and gas pressure in the extended narrow line regions (ENLRs) of four Seyfert galaxies from the integral field Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7). We demonstrate that there exist two distinct types of starburst-active galactic nucleus (AGN) mixing curves on standard emission line diagnostic diagrams, which reflect the balance between gas pressure and radiation pressure in the ENLR. In two of the galaxies the ENLR is radiation pressure dominated throughout and the ionization parameter remains constant (log U ˜ 0). In the other two galaxies radiation pressure is initially important, but gas pressure becomes dominant as the ionization parameter in the ENLR decreases from log U ˜ 0 to -3.2 ≲ log U ≲ -3.4. Where radiation pressure is dominant, the AGN regulates the density of the interstellar medium on kiloparsec scales and may therefore have a direct impact on star formation activity and/or the incidence of outflows in the host galaxy to scales far beyond the zone of influence of the black hole. We find that both radiation pressure dominated and gas pressure dominated ENLRs are dynamically active with evidence for outflows, indicating that radiation pressure may be an important source of AGN feedback even when it is not dominant over the entire ENLR.

Antiradiation Vaccine: Immunological neutralization of Radiation Toxins at Acute Radiation Syndromes.

NASA Astrophysics Data System (ADS)

Popov, Dmitri; Maliev, Slava

Introduction: Current medical management of the Acute Radiation Syndromes (ARS) does not include immune prophylaxis based on the Antiradiation Vaccine. Existing principles for the treatment of acute radiation syndromes are based on the replacement and supportive therapy. Haemotopoietic cell transplantation is recomended as an important method of treatment of a Haemopoietic form of the ARS. Though in the different hospitals and institutions, 31 pa-tients with a haemopoietic form have previously undergone transplantation with stem cells, in all cases(100%) the transplantants were rejected. Lethality rate was 87%.(N.Daniak et al. 2005). A large amount of biological substances or antigens isolated from bacterias (flagellin and derivates), plants, different types of venom (honeybees, scorpions, snakes) have been studied. This biological active substances can produce a nonspecific stimulation of immune system of mammals and protect against of mild doses of irradiation. But their radioprotection efficacy against high doses of radiation were not sufficient. Relative radioprotection characteristics or adaptive properties of antioxidants were expressed only at mild doses of radiation. However antioxidants demonstrated a very low protective efficacy at high doses of radiation. Some ex-periments demonstrated even a harmful effect of antioxidants administered to animals that had severe forms of the ARS. Only Specific Radiation Toxins roused a specific antigenic stim-ulation of antibody synthesis. An active immunization by non-toxic doses of radiation toxins includes a complex of radiation toxins that we call the Specific Radiation Determinant (SRD). Immunization must be provided not less than 24 days before irradiation and it is effective up to three years and more. Active immunization by radiation toxins significantly reduces the mortality rate (100%) and improves survival rate up to 60% compare with the 0% sur-vival rate among the irradiated animals in control groups. Material and Methods: The SRD molecules were isolated from Lymphatic Systems of animals that were irradiated with high doses of irradiation and had a clinical and laboratory picture of the Cerebral Acute Radia-tion Syndrome, Cardiovascular Acute Radiation Syndrome, Gastrointestinal Acute Radiation Syndrome, and Hematological Acute Radiation Syndrome. Our classification of radiation tox-ins includes 4 major groups: 1.SRD-1, Cerebrovascular neurotoxic Radiation Toxins (CvARS); 2.SRD-2, Cardiovascular Radiation Toxins(CrARS); 3.SRD-3,Gastrointestinal neurotoxic Ra-diation Toxins (GiARS); 4.SRD-4, Hematopietic Radiation Toxins (HpARS). Radiation tox-ins possess both toxic and immunological properties. But mechanisms of immune-toxicity by which radiation toxins stimulate development of the ARS are poorly understood. We have studied lethal toxicity of radiation toxins and an ability of specific antibodies to neutralize toxic activity of radiation toxins by specific antibodies. Results: The Blocking Antiradiation Antibodies induce an immunologically specific effect and inhibiting effects on radiation induced neuro-toxicity, vascular-toxicity, gastrointestinal toxcity, hematopoietic toxicity. Antiradiation Antibodies prevent the radiation induced cytolysis of selected groups of cells that are sensitive to radiation. The Blocking Antiradiation Antibodies are immunologically specific and can be produced by immunization with the different radiation toxins isolated from irradiated mam-mals. We propose that Specific Antiradiation Antibodies targeted against the radiation induced Toxins. Specific Antiradiation Antibodies neutralize toxic properties of radiation toxins. Anti-radiation Antibodies in different phases of the Acute Radiation Syndromes can compete with cytotoxic lymphocytes and prevent cytolysis mediated by cytotoxic lymphocytes. Conclusions: Immunological inhibition of cytotoxic and neurotoxic properties of Specific Radiation Toxins are significant factors for improving results of Medical Management of severe forms of the ARS and will optimize results of traditional methods of therapy of the ARS. Immunological inhi-bition of Radiation Toxins must be a part of technical procedure before haemotopoietic stem cells transplantation. Positive therapeutic results of neutralization of SRD RT could make a procedure of haemopoietic stem cell transplantation unnecessary.

Passive and active pulse stacking scheme for pulse shaping

DOEpatents

Harney, Robert C.; Schipper, John F.

1977-01-01

Apparatus and method for producing a sequence of radiation pulses with a pulse envelope of time variation which is controllable by an external electromagnetic signal applied to an active medium or by a sectored reflector, through which the radiation passes.

A Flash X-Ray Facility for the Naval Postgraduate School

DTIC Science & Technology

1985-06-01

ionizing radiation, *• NPS has had active programs with a Van de Graaff generator, a reactor, radioactive sources, X-ray machines and a linear electron ...interaction of radiation with matter and with coherent radiation. Currently the most active program is at the linear electron accelerator which over...twenty years has produced some 75 theses. The flash X-ray machine was obtained to expan-i and complement the capabilities of the linear electron

WNT activation by lithium abrogates TP53 mutation associated radiation resistance in medulloblastoma.

PubMed

Zhukova, Nataliya; Ramaswamy, Vijay; Remke, Marc; Martin, Dianna C; Castelo-Branco, Pedro; Zhang, Cindy H; Fraser, Michael; Tse, Ken; Poon, Raymond; Shih, David J H; Baskin, Berivan; Ray, Peter N; Bouffet, Eric; Dirks, Peter; von Bueren, Andre O; Pfaff, Elke; Korshunov, Andrey; Jones, David T W; Northcott, Paul A; Kool, Marcel; Pugh, Trevor J; Pomeroy, Scott L; Cho, Yoon-Jae; Pietsch, Torsten; Gessi, Marco; Rutkowski, Stefan; Bognár, Laszlo; Cho, Byung-Kyu; Eberhart, Charles G; Conter, Cecile Faure; Fouladi, Maryam; French, Pim J; Grajkowska, Wieslawa A; Gupta, Nalin; Hauser, Peter; Jabado, Nada; Vasiljevic, Alexandre; Jung, Shin; Kim, Seung-Ki; Klekner, Almos; Kumabe, Toshihiro; Lach, Boleslaw; Leonard, Jeffrey R; Liau, Linda M; Massimi, Luca; Pollack, Ian F; Ra, Young Shin; Rubin, Joshua B; Van Meir, Erwin G; Wang, Kyu-Chang; Weiss, William A; Zitterbart, Karel; Bristow, Robert G; Alman, Benjamin; Hawkins, Cynthia E; Malkin, David; Clifford, Steven C; Pfister, Stefan M; Taylor, Michael D; Tabori, Uri

2014-12-24

TP53 mutations confer subgroup specific poor survival for children with medulloblastoma. We hypothesized that WNT activation which is associated with improved survival for such children abrogates TP53 related radioresistance and can be used to sensitize TP53 mutant tumors for radiation. We examined the subgroup-specific role of TP53 mutations in a cohort of 314 patients treated with radiation. TP53 wild-type or mutant human medulloblastoma cell-lines and normal neural stem cells were used to test radioresistance of TP53 mutations and the radiosensitizing effect of WNT activation on tumors and the developing brain. Children with WNT/TP53 mutant medulloblastoma had higher 5-year survival than those with SHH/TP53 mutant tumours (100% and 36.6%±8.7%, respectively (p<0.001)). Introduction of TP53 mutation into medulloblastoma cells induced radioresistance (survival fractions at 2Gy (SF2) of 89%±2% vs. 57.4%±1.8% (p<0.01)). In contrast, β-catenin mutation sensitized TP53 mutant cells to radiation (p<0.05). Lithium, an activator of the WNT pathway, sensitized TP53 mutant medulloblastoma to radiation (SF2 of 43.5%±1.5% in lithium treated cells vs. 56.6±3% (p<0.01)) accompanied by increased number of γH2AX foci. Normal neural stem cells were protected from lithium induced radiation damage (SF2 of 33%±8% for lithium treated cells vs. 27%±3% for untreated controls (p=0.05). Poor survival of patients with TP53 mutant medulloblastoma may be related to radiation resistance. Since constitutive activation of the WNT pathway by lithium sensitizes TP53 mutant medulloblastoma cells and protect normal neural stem cells from radiation, this oral drug may represent an attractive novel therapy for high-risk medulloblastomas.

Toxic properties of specific radiation determinant molecules, derived from radiated species

NASA Astrophysics Data System (ADS)

Popov, Dmitri; Maliev, Vecheslav; Kedar, Prasad; Casey, Rachael; Jones, Jeffrey

Introduction: High doses of radiation induce the formation of radiation toxins in the organs of irradiated mammals. After whole body irradiation, cellular macromolecules and cell walls are damaged as a result of long-lived radiation-induced free radicals, reactive oxygen species, and fast, charged particles of radiation. High doses of radiation induce breaks in the chemical bonds of macromolecules and cross-linking reactions via chemically active processes. These processes result in the creation of novel modified macromolecules that possess specific toxic and antigenic properties defined by the type and dose of irradiation by which they are generated. Radiation toxins isolated from the lymph of irradiated animals are classified as hematotoxic, neurotoxic, and enteric non-bacterial (GI) radiation toxins, and they play an important role in the development of hematopoietic, cerebrovascular, and gastrointestinal acute radiation syndromes (ARS). Seven distinct toxins derived from post-irradiated animals have been designated as Specific Radiation Determinants (SRD): SRD-1 (neurotoxic radiation toxin generated by the cerebrovascular form of ARS), SRD-3 (enteric non-bacterial radiation toxins generated by the gastrointestinal form of ARS), and SRD-4 (hematotoxic radiation toxins generated by the hematological, bone marrow form of ARS). SRD-4 is further subdivided into four groups depending on the severity of the ARS induced: SRD-4/1, mild ARS; SRD-4/2, moderate ARS; SRD-4/3, severe ARS; and SRD-4/4, extremely severe ARS. The seventh SRD, SRD-2 is a toxic extract derived from animals suffering from a fourth form of ARS, as described in European literature and produces toxicity primarily in the autonimic nervous system. These radiation toxins have been shown to be responsible for the induction of important pathophysiological, immunological, and biochemical reactions in ARS. Materials and Methods: These studies incorporated the use of statistically significant numbers of a variety of animals. Lymphatic fluid was collected from the thoracic ducts of bovine species exposed to lethal doses of gamma radiation, and the SRDs were separated by size exclusion gel filtration and high-performance liquid chromatography. We compared the toxicity of isolated radiation toxins in a variety of animals. The clinical characteristics of ARS induced by intravenous or intra-muscular injections of radiation toxins were observed. Results: In radiation-na¨ animals (rats, rabbits, and sheep), toxicity was defined ıve by observing the timing and rate of lethality following injections with extracted radiation toxins (SRDs). Preparations of SRD-1 were injected intra-muscularly in doses of 5 or 10 mg/kg body weight. We observed the development of cerebrovascular ARS with 100% lethality at 10-30 minutes after injection. Analysis of the toxicity of different forms of radiation toxins showed that cerebrovascular neurotoxins possess the highest toxicity compared with other forms of radiation toxins. The other SRD's were also injected into radiation-naive animals and observed for subsequent toxicity/lethality, with the other SRDs producing less virulent forms of ARS. However, both the SRD-2- and SRD-3-injected animals also suffered lethality between 2 and 30 days post-injection. Conclusions: We have observed that radiation toxins are transported from the cells and tissues of irradiated organisms to the interstitial blood and lymphatic fluids, and that this migration of radiation toxins occurs hours after irradiation. Upon analysis of the results of our research and literature sources, we postulate that radiation toxins arise from the radiation-induced chemical modification of macromolecules resident in cell membranes and other cellular structures. Furthermore, we postulate that these altered macromolecules are not processed by antigen processing cells, but instead bind to class II MHC molecules and TCR-beta chains. This causes nonspecific activation of T cells, pro-inflammatory agents such as cytokines and isozymes of phospholipase A2 and phospholipase C, and platelet-activating factor. Longer-term effects induced by the altered macromolecules include the activation of cytotoxic T cells, which induces cytolysis in radiation-damaged cells. Activated CD8+ T cells produce tumor necrosis factor-B and additional cytokines. By these mechanisms, we postulate that radiation toxins generate the pathophysiological reactions associated with acute radiation syndromes.

Modular and Stochastic Approaches to Molecular Pathway Models of ATM, TGF beta, and WNT Signaling

NASA Technical Reports Server (NTRS)

Cucinotta, Francis A.; O'Neill, Peter; Ponomarev, Artem; Carra, Claudio; Whalen, Mary; Pluth, Janice M.

2009-01-01

Deterministic pathway models that describe the biochemical interactions of a group of related proteins, their complexes, activation through kinase, etc. are often the basis for many systems biology models. Low dose radiation effects present a unique set of challenges to these models including the importance of stochastic effects due to the nature of radiation tracks and small number of molecules activated, and the search for infrequent events that contribute to cancer risks. We have been studying models of the ATM, TGF -Smad and WNT signaling pathways with the goal of applying pathway models to the investigation of low dose radiation cancer risks. Modeling challenges include introduction of stochastic models of radiation tracks, their relationships to more than one substrate species that perturb pathways, and the identification of a representative set of enzymes that act on the dominant substrates. Because several pathways are activated concurrently by radiation the development of modular pathway approach is of interest.

Active structural acoustic control of noise transmission through double panel systems

NASA Astrophysics Data System (ADS)

Carneal, James P.; Fuller, Chris R.

1995-04-01

A preliminary parametric study of active control of sound transmission through double panel systems has been experimentally performed. The technique used is the active structural acoustic control (ASAC) approach where control inputs, in the form of piezoelectric actuators, were applied to the structure while the radiated pressure field was minimized. Results indicate the application of control inputs to the radiating panel resulted in greater transmission loss due to its direct effect on the nature of the structural-acoustic coupling between the radiating panel and the receiving chamber. Increased control performance was seen in a double panel system consisting of a stiffer radiating panel with a lower modal density. As expected, more effective control of a radiating panel excited on-resonance is achieved over one excited off-resonance. In general, the results validate the ASAC approach for double panel systems and demonstrate that it is possible to take advantage of double panel behavior to enhance control performance, although it is clear that further research must be done to understand the physics involved.

NASA Fundamental Remote Sensing Science Research Program

NASA Technical Reports Server (NTRS)

1984-01-01

The NASA Fundamental Remote Sensing Research Program is described. The program provides a dynamic scientific base which is continually broadened and from which future applied research and development can draw support. In particular, the overall objectives and current studies of the scene radiation and atmospheric effect characterization (SRAEC) project are reviewed. The SRAEC research can be generically structured into four types of activities including observation of phenomena, empirical characterization, analytical modeling, and scene radiation analysis and synthesis. The first three activities are the means by which the goal of scene radiation analysis and synthesis is achieved, and thus are considered priority activities during the early phases of the current project. Scene radiation analysis refers to the extraction of information describing the biogeophysical attributes of the scene from the spectral, spatial, and temporal radiance characteristics of the scene including the atmosphere. Scene radiation synthesis is the generation of realistic spectral, spatial, and temporal radiance values for a scene with a given set of biogeophysical attributes and atmospheric conditions.

Observations of energitic radiation bursts from thunder activities

NASA Astrophysics Data System (ADS)

Tsuchiya, H.; Enoto, T.; Torii, T.; Yuasa, T.; Yamada, S.; Kitacuhi, T.; Nakazawa, K.; Kato, H.; Okano, M.; Makishima, K.

2009-04-01

Energetic radiation bursts have been observed during strong thunderstorms by ground-based detectors as well as high-mountain ones. Those radiation bursts are thought to result from runaway electrons originating from electrons accelerated by strong electric field in lightning discharges and thunderclouds, and hence provide a valuable key to understand particle acceleration in thunder activity. Interestingly, they can be categorized into two bursts by their duration. One consists of short bursts lasting for milli-seconds or less. The other comprises long bursts having duration of a few seconds. In order to better understand both short and long bursts, we have conducted experiments at coastal area of the Japan Sea and a 2770-m altitude observatory. In this talk, we will report on those experiments, showing the two experiments has successfully observed both short and long bursts. Especially, we will focus on high-energy radiations extending over MeV energies, and then discuss a plausible model to explain how those high-energy radiations are produced in thunder activity.

Induction of Cell Death through Alteration of Oxidants and Antioxidants in Epithelial Cells Exposed to High Energy Protons

NASA Technical Reports Server (NTRS)

Ramesh, Govindarajan; Wu, Honglu

2012-01-01

Radiation affects several cellular and molecular processes including double strand breakage, modifications of sugar moieties and bases. In outer space, protons are the primary radiation source which poses a range of potential health risks to astronauts. On the other hand, the use of proton radiation for tumor radiation therapy is increasing as it largely spares healthy tissues while killing tumor tissues. Although radiation related research has been conducted extensively, the molecular toxicology and cellular mechanisms affected by proton radiation remain poorly understood. Therefore, in the present study, we irradiated rat epithelial cells (LE) with different doses of protons and investigated their effects on cell proliferation and cell death. Our data showed an inhibition of cell proliferation in proton irradiated cells with a significant dose dependent activation and repression of reactive oxygen species (ROS) and antioxidants, glutathione and superoxide dismutase respectively as compared to control cells. In addition, apoptotic related genes such as caspase-3 and -8 activities were induced in a dose dependent manner with corresponding increased levels of DNA fragmentation in proton irradiated cells than control cells. Together, our results show that proton radiation alters oxidant and antioxidant levels in the cells to activate apoptotic pathway for cell death.

CERTAIN SPECIFIC FEATURES OF THE HIGHER NERVOUS ACTIVITY OF FULLY GROWN ANIMALS IRRADIATED ANTENATALLY WITH IONIZING RADIATION. I. THE INFLUENCE OF IONIZING RADIATION ON THE OFFSPRING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Piontkovskii, I.A.

1958-09-01

Irradiation of pregnant female aniamals and women with ionizing radiation may cause the appearance of a variety of congenital deformities in the offspring and may interfere with their postnatal development. L. Hicks points out the particular sensitivity of the nervous system of the embryo to ionizing radiation. Thus irradiation of rats on the 9th, 11th, 12th, and 13th days of prenatal development may cause, in addition to somatic deformities, anencephaly (on the 9th day), hydrocephaly (on the 11th day), microcephaly (on the 12th13th day), failure of development of the subcortical structures, the corpora callosa and so on. The influence ofmore » ionizing radiation on the nervous system during antenatal irradiation has been studied mainly morphologically. There are no indications in the literature of the state of the higher nervous activity of fully grown animals exposed at various periods of their antenatal development to the action of ionizing radiation. The effect of ionizing radiation, applied in various doses and at different stages of embryonic development, on the state of the higher nervous activity of animals was studied. (auth)« less

In vivo sensitivity of the embryonic and adult neural stem cell compartments to low-dose radiation.

PubMed

Barazzuol, Lara; Jeggo, Penny A

2016-08-01

The embryonic brain is radiation-sensitive, with cognitive deficits being observed after exposure to low radiation doses. Exposure of neonates to radiation can cause intracranial carcinogenesis. To gain insight into the basis underlying these outcomes, we examined the response of the embryonic, neonatal and adult brain to low-dose radiation, focusing on the neural stem cell compartments. This review summarizes our recent findings. At E13.5-14.5 the embryonic neocortex encompasses rapidly proliferating stem and progenitor cells. Exploiting mice with a hypomorphic mutation in DNA ligase IV (Lig4(Y288C) ), we found a high level of DNA double-strand breaks (DSBs) at E14.5, which we attribute to the rapid proliferation. We observed endogenous apoptosis in Lig4(Y288C) embryos and in WT embryos following exposure to low radiation doses. An examination of DSB levels and apoptosis in adult neural stem cell compartments, the subventricular zone (SVZ) and the subgranular zone (SGZ) revealed low DSB levels in Lig4(Y288C) mice, comparable with the levels in differentiated neuronal tissues. We conclude that the adult SVZ does not incur high levels of DNA breakage, but sensitively activates apoptosis; apoptosis was less sensitively activated in the SGZ, and differentiated neuronal tissues did not activate apoptosis. P5/P15 mice showed intermediate DSB levels, suggesting that DSBs generated in the embryo can be transmitted to neonates and undergo slow repair. Interestingly, this analysis revealed a stage of high endogenous apoptosis in the neonatal SVZ. Collectively, these studies reveal that the adult neural stem cell compartment, like the embryonic counterpart, can sensitively activate apoptosis. © The Author 2016. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

Biosentinel: Developing a Space Radiation Biosensor

NASA Technical Reports Server (NTRS)

Santa Maria, Sergio R.; Marina, Diana B.; Parra, Macarena P.; Boone, Travis D.; Tan, Ming; Ricco, Antonio J.; Straume, Tore N.; Lusby, Terry C.; Harkness, T.; Reiss-Bubenheim, Debra;

Review of Radioisotopes as Radiological Weapons

DTIC Science & Technology

2016-06-01

doses of radiation . Two of the woodsmen devel- oped serious symptoms of Acute Radiation Syndrome (ARS) and beta radiation burns that required...or organs). Absorbed dose is usually defined as energy deposited (joule) per unit of mass (kilogram). See gray and rad. Acute Radiation Syndrome ...AI alveolar-interstitial ALARA as low as reasonably achievable ARS Acute Radiation Syndrome Bq becquerel C Activity of Concern CDC Centers for

Principals Of Radiation Toxicology: Important Aspects.

NASA Astrophysics Data System (ADS)

Popov, Dmitri; Maliev, Slava; Jones, Jeffrey

“All things are poison, and nothing is without poison; only the dose permits something not to be poisonous.” Paracelsus Key Words: Radiation Toxins (RT), Radiation Toxicants (RTc), Radiation Poisons (RP), Radiation Exposure (RE), Radiation Toxicology is the science about radiation poisons. [D.Popov et al. 2012,J.Zhou et al. 2007,] Radiation Toxins is a specific proteins with high enzymatic activity produced by living irradiated mammals. [D.Popov et al. 2012,] Radiation Toxicants is a substances that produce radiomimetics effects, adverse biological effects which specific for radiation. [D.Popov et al. 2012,] Radiation Toxic agent is specific proteins that can produce pathological biological effects specific for physical form of radiation.[D.Popov et al. 1990,2012,V. Maliev 2007] Different Toxic Substances isolated from cells or from blood or lymph circulation. [Kudriashov I. et al. 1970, D.Popov et al. 1990,2012,V. Maliev et al. 2007,] Radiation Toxins may affects many organs or specific organ, tissue, specific group of cells. [Kudriashov I. et al. 1970, D.Popov et al. 1990,2012,V. Maliev et al. 2007] For example: Radiation Toxins could induce collective toxic clinical states to include: systemic inflammatory response syndrome (SIRS),toxic multiple organ injury (TMOI), toxic multiple organ dysfunction syndromes (TMODS),and finally, toxic multiple organ failure (TMOF). [T. Azizova et al. 2005, Konchalovsky et al., 2005, D. Popov et al 2012] However, Radiation Toxins could induce specific injury of organs or tissue and induce Acute Radiation Syndromes such as Acute Radiation Cerebrovascular Syndrome, Acute Radiation Cardiovascular Syndrome, Acute Radiation Hematopoietic Syndrome, Acute Radiation GastroIntestinal Syndrome. [ D.Popov et al. 1990, 2012, V. Maliev et al. 2007] Radiation Toxins correlates with Radiation Exposure and the dose-response relationship is a fundamental and essential concept in classic Toxicology and Radiation Toxicology.[ D.Popov et al. 1990, 2012] Moderate and high doses of radiation induces necrosis of radiosensitive cells with the subsequent formation of radiation toxins and their induced acute inflammatory processes. Radiation necrosis is the most substantial and most severe form of radiation induced injury, and when widespread, has grave therapeutic implications. [D. Popov et al. 1990, 2012,Claudio A. et al. 2002, Robertson J. et al. 2002, ] Relatively small doses of Radiation Toxins induce apoptosis and high doses of Radiation Toxins induce necrosis. [Rastogi P. et al. 2009, D. Popov et al. 1990, 2012,] Threshold of Toxic Effects occurs and can be defined. [D. Popov et al. 2012, ] Radiation Toxins affects Somatic cells and Germ Cells. Radiation Toxins can induce teratogenic processes. Specific Toxicity of Radiation Toxins can affects developing fetus. Material and Methods, Results: http://www.intechopen.com/books/current-topics-in-ionizing-radiation-research/radiation-toxins-molecular-mechanisms-of-toxicity-and-radiomimetic-properties- Conclusion: Radiation is a physical agent - induce activation of some secretory proteins with high enzymatic activity. This proteins called as Radiation Toxins can produce specific for radiation biological and toxic effects after administration to radiation naive mammals. [V. Maliev et al. 2007, D. Popov et al. 1990, 2012] Radiation Toxins are teratogenic and oncogenic. Radiation Toxins effects depend on Administered Dose and Radiation effects depend on Exposure Dose and Absorbed Dose. The levels of Radiation Toxins correlates with Radiation Exposure.

Evaluation of NF-kappaB Pathway Inhibition for Space Radiation Biology Research

NASA Astrophysics Data System (ADS)

Koch, Kristina; Hellweg, Christine; Baumstark-Khan, Christa; Schmitz, Claudia; Lau, Patrick; Testard, Isabelle; Reitz, Guenther

Radiation is a potentially limiting factor for long term orbital and interplanetary missions. To improve risk estimation and to allow development of appropriate countermeasures, the study of the cellular radiation response is necessary. The anti-apoptotic factor nuclear factor κB (NF-κB) was identified as important modulating factor in the cellular response to heavy ions (Radiat. Res. 164: 527-530, 2005). This transcription factor could improve cellular survival after exposure to high radiation doses and influence the cancer risk of astronauts exposed to low doses of cosmic radiation. Therefore, the inhibition of selected NF-κB pathway compo-nents might help to identify possible pharmacological targets. It is supposed that the ATM kinase mediates the signal from damaged DNA in the nucleus to kinases in the cytoplasm. For liberation of NF-κB and its nuclear translocation, the inhibitor of NF-κB (IκB) has to be degraded in the proteasom. In this work, the efficacy and cytotoxicity of ATM, NF-κB and the proteasome inhibitors were analyzed using recombinant HEK-pNF-κB-d2EGFP/Neo cells. In the recommended concentration range, only the NF-κB inhibitor caffeic acid phenethyl ester (CAPE) displayed considerable cytotoxicity, while the others were not toxic. The inhibition of ATM by KU-55933 suppresses the X-ray and heavy ion (13 C, 35 MeV/u, LET 70 keV/m) induced activation of NF-κB dependent gene expression, indicating the central position of ATM in radiation induced NF-κB activation. CAPE and capsaicin partially inhibited NF-κB acti-vation by the cytokine tumor necrosis factor α. The proteasome inhibitor MG-132 completely abolished the activation and was therefore used for short-term incubation experiments with X-rays. MG-132 suppressed the X-ray induced NF-κB activation in HEK-pNF-κB-d2EGFP/Neo cells entirely. The results lead to the conclusion that ATM and the proteasomal degradation of IκB are essential prerequisites for radiation induced NF-κB activation. KU-55933 and MG-132 will be useful in studies of the NF-κB pathway involvement in the cellular response to heavy ion exposure and other space relevant radiation qualities.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Warkentin, Matthew, E-mail: maw64@cornell.edu; Thorne, Robert E.

Radiation damage to protein crystals exhibits two regimes of temperature-activated behavior between T = 300 and 100 K, with a crossover at the protein glass transition near 200 K. These results have implications for mechanistic studies of proteins and for structure determination when cooling to T = 100 K creates excessive disorder. The temperature-dependence of radiation damage to thaumatin crystals between T = 300 and 100 K is reported. The amount of damage for a given dose decreases sharply as the temperature decreases from 300 to 220 K and then decreases more gradually on further cooling below the protein-solvent glassmore » transition. Two regimes of temperature-activated behavior were observed. At temperatures above ∼200 K the activation energy of 18.0 kJ mol{sup −1} indicates that radiation damage is dominated by diffusive motions in the protein and solvent. At temperatures below ∼200 K the activation energy is only 1.00 kJ mol{sup −1}, which is of the order of the thermal energy. Similar activation energies describe the temperature-dependence of radiation damage to a variety of solvent-free small-molecule organic crystals over the temperature range T = 300–80 K. It is suggested that radiation damage in this regime is vibrationally assisted and that the freezing-out of amino-acid scale vibrations contributes to the very weak temperature-dependence of radiation damage below ∼80 K. Analysis using the radiation-damage model of Blake and Phillips [Blake & Phillips (1962 ▶), Biological Effects of Ionizing Radiation at the Molecular Level, pp. 183–191] indicates that large-scale conformational and molecular motions are frozen out below T = 200 K but become increasingly prevalent and make an increasing contribution to damage at higher temperatures. Possible alternative mechanisms for radiation damage involving the formation of hydrogen-gas bubbles are discussed and discounted. These results have implications for mechanistic studies of proteins and for studies of the protein glass transition. They also suggest that data collection at T ≃ 220 K may provide a viable alternative for structure determination when cooling-induced disorder at T = 100 is excessive.« less

Cerebrovascular Acute Radiation Syndrome : Radiation Neurotoxins, Mechanisms of Toxicity, Neuroimmune Interactions.

NASA Astrophysics Data System (ADS)

Popov, Dmitri; Maliev, Slava

Introduction: Cerebrovascular Acute Radiation Syndrome (CvARS) is an extremely severe in-jury of Central Nervous System (CNS) and Peripheral Nervous System (PNS). CvARS can be induced by the high doses of neutron, heavy ions, or gamma radiation. The Syndrome clinical picture depends on a type, timing, and the doses of radiation. Four grades of the CvARS were defined: mild, moderate, severe, and extremely severe. Also, four stages of CvARS were developed: prodromal, latent, manifest, outcome -death. Duration of stages depends on the types, doses, and time of radiation. The CvARS clinical symptoms are: respiratory distress, hypotension, cerebral edema, severe disorder of cerebral blood microcirculation, and acute motor weakness. The radiation toxins, Cerebro-Vascular Radiation Neurotoxins (SvARSn), determine development of the acute radiation syndrome. Mechanism of action of the toxins: Though pathogenesis of radiation injury of CNS remains unknown, our concept describes the Cv ARS as a result of Neurotoxicity and Excitotoxicity, cell death through apoptotic necrosis. Neurotoxicity occurs after the high doses radiation exposure, formation of radiation neuro-toxins, possible bioradicals, or group of specific enzymes. Intracerebral hemorrhage can be a consequence of the damage of endothelial cells caused by radiation and the radiation tox-ins. Disruption of blood-brain barrier (BBB)and blood-cerebrospinal fluid barrier (BCFB)is possibly the most significant effect of microcirculation disorder and metabolic insufficiency. NMDA-receptors excitotoxic injury mediated by cerebral ischemia and cerebral hypoxia. Dam-age of the pyramidal cells in layers 3 and 5 and Purkinje cell layer the cerebral cortex , damage of pyramidal cells in the hippocampus occur as a result of cerebral ischemia and intracerebral bleeding. Methods: Radiation Toxins of CV ARS are defined as glycoproteins with the molec-ular weight of RT toxins ranges from 200-250 kDa and with high enzymatic activity. Radiation Toxins (SRD-1)had been isolated from Central Lymph of irradiated animals (cows, sheep, pigs). Experiments to study toxicity of Radiation Neurotoxins had been performed. Intravenous (IV) and intramuscular (IM) administration of RT SRD-1 to radiation naive animals had induced acute toxicity which referred to the harmful effects generated by high doses of radiation. In-jection of toxic doses of RT SRD-1 (Toxic doses: 0,1 mg/kg, 0,5mg/kg, 1 mg/kg, 10mg/kg,30 mg/kg, 50mg/kg,70 mg/kg,100 mg/kg, 110mg/kg)were compared to the similar effects caused by high doses of radiation. Results: Injection of SRD-1 ( Neurotoxin Cv ARS)of all ten tested toxic doses had caused a death of radiation naive animals within the first hours after admin-istration of toxins. For all animals in all experiments, a short period of extreme agitation was replaced by deep coma, and suppression of blood circulation and breathing. The results of postmortem section had showed characteristics of intra-cortical hemorrhage. Conclusions: Acute radiation injury induces a disorder of blood supply of the Central Nervous System (CNS). However, administration of SRD-1 Radiation Toxins to radiation naive animals produces crit-ically important inflammatory reactions with hemorrhagic stroke development. Neurotoxicity and Excitotoxicity are two stages of the pathological processes resulted in damaging and killing nerve cells thorough apoptotic necrosis. Excitotoxicity is well known as a pathological process that occurs when important excitatory neurotransmitters (glutamate, serotonin) over-activate the receptors -NMDA, AMPA, 5HT1, 5HT2, 5H3. Radiation Neurotoxins possibly act on the same receptors and activate the cell death mechanisms through direct or indirect excessive activation of same receptors.

Raman spectroscopic analysis of the responds of desert cyanobacterium Nostoc sp under UV-B radiation

NASA Astrophysics Data System (ADS)

Wang, Gaohong; Hao, Zongjie; Hu, Chunxiang; Liu, Yongding

Cyanobacteria are renowned for tolerating extremes of desiccation, UV radiation, freezethaw cycles, hypersalinity and oligotrophy, which make them as candidate par excellence for terraforming in extraterrestrial planet. Recently Raman spectrum was applied to study the biochemical information changes in different field of life science. In this study, we investigated the respond of desert cyanobactreium Nostoc sp under UV-B radiation via FT-Raman spectra. It was found that the spectral biomarkers of protectant molecular of UV radiation such as β-carotene and scytonemin were induced by UV-B radiation, but Chlorophyll a content was decreased, and also the photosynthesis activity was inhibited significantly. After light adaptation without UV-B radiation, the Chlorophyll a content and photosynthesis activity returned to high level, butβ-carotene and scytonemin content remained in the cells. Those results indicated that desert Cyanobacteria have good adaptation ability for UV-B radiation and synthesis of protectant molecular may be an effective strategy for its adaptation in evolution.

IBPRO - A Novel Short-Duration Teaching Course in Advanced Physics and Biology Underlying Cancer Radiotherapy.

PubMed

Joiner, Michael C; Tracey, Monica W; Kacin, Sara E; Burmeister, Jay W

2017-06-01

This article provides a summary and status report of the ongoing advanced education program IBPRO - Integrated course in Biology and Physics of Radiation Oncology. IBPRO is a five-year program funded by NCI. It addresses the recognized deficiency in the number of mentors available who have the required knowledge and skill to provide the teaching and training that is required for future radiation oncologists and researchers in radiation sciences. Each year, IBPRO brings together 50 attendees typically at assistant professor level and upwards, who are already qualified/certified radiation oncologists, medical physicists or biologists. These attendees receive keynote lectures and activities based on active learning strategies, merging together the clinical, biological and physics underpinnings of radiation oncology, at the forefront of the field. This experience is aimed at increasing collaborations, raising the level and amount of basic and applied research undertaken in radiation oncology, and enabling attendees to confidently become involved in the future teaching and training of researchers and radiation oncologists.

Active Solid State Dosimetry for Lunar EVA

NASA Technical Reports Server (NTRS)

Wrbanek, John D.; Fralick, Gustave C.; Wrbanek, Susan Y.; Chen, Liang-Yu.

2006-01-01

The primary threat to astronauts from space radiation is high-energy charged particles, such as electrons, protons, alpha and heavier particles, originating from galactic cosmic radiation (GCR), solar particle events (SPEs) and trapped radiation belts in Earth orbit. There is also the added threat of secondary neutrons generated as the space radiation interacts with atmosphere, soil and structural materials.[1] For Lunar exploration missions, the habitats and transfer vehicles are expected to provide shielding from standard background radiation. Unfortunately, the Lunar Extravehicular Activity (EVA) suit is not expected to afford such shielding. Astronauts need to be aware of potentially hazardous conditions in their immediate area on EVA before a health and hardware risk arises. These conditions would include fluctuations of the local radiation field due to changes in the space radiation field and unknown variations in the local surface composition. Should undue exposure occur, knowledge of the dynamic intensity conditions during the exposure will allow more precise diagnostic assessment of the potential health risk to the exposed individual.[2

Active noise control using noise source having adaptive resonant frequency tuning through stress variation

NASA Technical Reports Server (NTRS)

Pla, Frederic G. (Inventor); Renshaw, Anthony A. (Inventor); Rajiyah, Harindra (Inventor); Hedeen, Robert A. (Inventor)

1995-01-01

A noise source for an aircraft engine active noise cancellation system in which the resonant frequency of a noise radiating element is tuned to permit noise cancellation over a wide range of frequencies. The resonant frequency of the noise radiating element is tuned by an expandable ring embedded in the noise radiating element. Excitation of the ring causes expansion or contraction of the ring, thereby varying the stress in the noise radiating element. The ring is actuated by a controller which receives input of a feedback signal proportional to displacement of the noise radiating element and a signal corresponding to the blade passage frequency of the engine's fan. In response, the controller determines a control signal which is sent to the ring, causing the ring to expand or contract. Instead of a single ring embedded in the noise radiating panel, a first expandable ring can be bonded to one side of the noise radiating element, and a second expandable ring can be bonded to the other side.

IBPRO – a novel short-duration teaching course in advanced physics and biology underlying cancer radiotherapy

PubMed Central

Joiner, Michael C.; Tracey, Monica W.; Kacin, Sara E.; Burmeister, Jay W.

2017-01-01

This article provides a summary and status report of the ongoing advanced education program IBPRO – Integrated course in Biology and Physics of Radiation Oncology. IBPRO is a five-year program funded by NCI. It addresses the recognized deficiency in the number of mentors available who have the required knowledge and skill to provide the teaching and training that is required for future radiation oncologists and researchers in radiation sciences. Each year, IBPRO brings together 50 attendees typically at assistant professor level and upwards, who are already qualified/certified radiation oncologists, medical physicists or biologists. These attendees receive keynote lectures and activities based on active learning strategies, merging together the clinical, biological and physics underpinnings of radiation oncology, at the forefront of the field. This experience is aimed at increasing collaborations, raising the level and amount of basic and applied research undertaken in radiation oncology, and enabling attendees to confidently become involved in the future teaching and training of researchers and radiation oncologists. PMID:28328309

Status of LDEF radiation modeling

NASA Technical Reports Server (NTRS)

Watts, John W.; Armstrong, T. W.; Colborn, B. L.

1995-01-01

The current status of model prediction and comparison with LDEF radiation dosimetry measurements is summarized with emphasis on major results obtained in evaluating the uncertainties of present radiation environment model. The consistency of results and conclusions obtained from model comparison with different sets of LDEF radiation data (dose, activation, fluence, LET spectra) is discussed. Examples where LDEF radiation data and modeling results can be utilized to provide improved radiation assessments for planned LEO missions (e.g., Space Station) are given.

Activities of the National Institute of Radiological Sciences

NASA Astrophysics Data System (ADS)

1994-01-01

This annual report presents activities at the National Institute of Radiological Sciences (NIRS) in Japan during the period April 1992-March 1993. The activities are divided into research, technical aids, training, medical services, management, library or editing, and international cooperation. Research activities are arranged with twelve sections. The first section on special researches deals with continuing research projects entitled: (1) 'Biological Risk Evaluation in Public Exposure'; (2) 'Exposure Assessment in the Environment and the Public Through Food Chain'; (3) 'Medical Use of Accelerated Heavy Ions'; and (4) 'Preliminary Study for the Demonstration of Dose-Response Relationships in Low-Dose Range'. All projects except for project (4) will be finished up to March 1993. The section of assigned researches covers four titles. The section of ordinary researches covers physics (four titles), pharmacochemistry (four), biology (three), genetics (four), physiopathology (four), cytological radiation injuries (three), internal exposure (four), environmental science (four), clinical research (four), clinical research for radiation injuries (three), medical use of heavy particles (three), environmental radiation ecology (three), and aquatic radiation ecology (two). The section on technical aids gives an overview of technical services, radiation safety, animal and plant management, and cyclotron management. Appendices give the information on personnel in NIRS.

A Radiation Laboratory Curriculum Development at Western Kentucky University

NASA Astrophysics Data System (ADS)

Barzilov, Alexander P.; Novikov, Ivan S.; Womble, Phil C.

2009-03-01

We present the latest developments for the radiation laboratory curriculum at the Department of Physics and Astronomy of Western Kentucky University. During the last decade, the Applied Physics Institute (API) at WKU accumulated various equipment for radiation experimentation. This includes various neutron sources (computer controlled d-t and d-d neutron generators, and isotopic 252 Cf and PuBe sources), the set of gamma sources with various intensities, gamma detectors with various energy resolutions (NaI, BGO, GSO, LaBr and HPGe) and the 2.5-MeV Van de Graaff particle accelerator. XRF and XRD apparatuses are also available for students and members at the API. This equipment is currently used in numerous scientific and teaching activities. Members of the API also developed a set of laboratory activities for undergraduate students taking classes from the physics curriculum (Nuclear Physics, Atomic Physics, and Radiation Biophysics). Our goal is to develop a set of radiation laboratories, which will strengthen the curriculum of physics, chemistry, geology, biology, and environmental science at WKU. The teaching and research activities are integrated into real-world projects and hands-on activities to engage students. The proposed experiments and their relevance to the modern status of physical science are discussed.

75 FR 55366 - In the Matter of Mark M. Ficek; Order Prohibiting Involvement in NRC-Licensed Activities...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-10

... (Effective Immediately) Mr. Mark M. Ficek is the President, owner, and former radiation safety officer (RSO... new radiation safety officer, and due to expire on February 28, 2016. The license authorizes Mattingly... assessing Mattingly's entire radiation safety program, providing radiation safety training to the Mattingly...

Photosynthetically active radiation (PAR) x ultraviolet radiation (UV) interact to initiate solar injury in apple

USDA-ARS?s Scientific Manuscript database

Sunburn or solar injury (SI) in apple is associated with high temperature, high visible light and ultraviolet radiation (UV). Fruit surface temperature (FST) thresholds for SI related disorders have been developed but there are no thresholds established for solar radiation. The objectives of the s...

Active noise control using noise source having adaptive resonant frequency tuning through stiffness variation

NASA Technical Reports Server (NTRS)

Rajiyah, Harindra (Inventor); Hedeen, Robert A. (Inventor); Pla, Frederic G. (Inventor); Renshaw, Anthony A. (Inventor)

1995-01-01

A noise source for an aircraft engine active noise cancellation system in which the resonant frequency of a noise radiating element is tuned to permit noise cancellation over a wide range of frequencies. The resonant frequency of the noise radiating element is tuned by a plurality of force transmitting mechanisms which contact the noise radiating element. Each one of the force transmitting mechanisms includes an expandable element and a spring in contact with the noise radiating element so that excitation of the element varies the spring force applied to the noise radiating element. The elements are actuated by a controller which receives input of a signal proportional to displacement of the noise radiating element and a signal corresponding to the blade passage frequency of the engine's fan. In response, the controller determines a control signal which is sent to the elements and causes the spring force applied to the noise radiating element to be varied. The force transmitting mechanisms can be arranged to either produce bending or linear stiffness variations in the noise radiating element.

Temporary microglia-depletion after cosmic radiation modifies phagocytic activity and prevents cognitive deficits.

PubMed

Krukowski, Karen; Feng, Xi; Paladini, Maria Serena; Chou, Austin; Sacramento, Kristen; Grue, Katherine; Riparip, Lara-Kirstie; Jones, Tamako; Campbell-Beachler, Mary; Nelson, Gregory; Rosi, Susanna

2018-05-18

Microglia are the main immune component in the brain that can regulate neuronal health and synapse function. Exposure to cosmic radiation can cause long-term cognitive impairments in rodent models thereby presenting potential obstacles for astronauts engaged in deep space travel. The mechanism/s for how cosmic radiation induces cognitive deficits are currently unknown. We find that temporary microglia depletion, one week after cosmic radiation, prevents the development of long-term memory deficits. Gene array profiling reveals that acute microglia depletion alters the late neuroinflammatory response to cosmic radiation. The repopulated microglia present a modified functional phenotype with reduced expression of scavenger receptors, lysosome membrane protein and complement receptor, all shown to be involved in microglia-synapses interaction. The lower phagocytic activity observed in the repopulated microglia is paralleled by improved synaptic protein expression. Our data provide mechanistic evidence for the role of microglia in the development of cognitive deficits after cosmic radiation exposure.

Effect of radiation on red cell membrane and intracellular oxidative defense systems.

PubMed

Katz, D; Mazor, D; Dvilansky, A; Meyerstein, N

1996-03-01

Ionizing radiation is currently used for prevention of transfusion associated graft versus host disease (TAGVHD). As radiation damage is associated with the production of activated oxygen species, the aim of this study was to observe the immediate effect of ionizing radiation on red cell membrane and intracellular oxidative defense systems. Neonatal and iron deficiency (IDA) cells, known for their increased sensitivity to oxidative stress, were chosen and compared with normal cells. Irradiation was performed in doses of 1500 cGy, 3000 cGy and 5000 cGy. GSH and methemoglobin levels and the activity of different antioxidant enzymes, measured under optimal in vitro conditions, were preserved in all cells after irradiation. Only radiation at the highest does of 5000 cGy, caused significant potassium leakage in neonatal cells and insignificant increase in IDA cells. Thus, cells with increased sensitivity to oxidative stress are more susceptible to damage by ionizing radiation than normal cells.

Acoustic transmission and radiation analysis of adaptive shape-memory alloy reinforced laminated plates

NASA Astrophysics Data System (ADS)

Liang, C.; Rogers, C. A.; Fuller, C. R.

1991-02-01

A theoretical analysis of sound transmission/radiation of shape-memory alloy (SMA) hybrid composite panels is presented. Unlike other composite materials, SMA hybrid composite is dynamically tunable by electrical activation of the SMA fibers and has numerous active control capabilities. Two of the concepts that will be briefly described and utilized in this paper are referred to as active property tuning (APT) and active strain energy tuning (ASET). Tuning or activating the embedded shape-memory alloy fibers in conventional composite materials changes the overall stiffness of the SMA hybrid composite structure and consequently changes natural frequency and mode shapes. The sound transmission and radiation from a composite panel is related to its frequency and mode shapes. Because of the capability to change both the natural frequency and mode shapes, the acoustic characteristics of SMA hybrid composite plates can be changed as well. The directivity pattern, radiation efficiency, and transmission loss of laminated composite materials are investigated based on 'composite' mode shapes in order to derive a basic understanding of the nature and authority of acoustic control by use of SMA hybrid composites.

The effect of melatonin on eye lens of rats exposed to ultraviolet radiation.

PubMed

Anwar, M M; Moustafa, M A

2001-05-01

We investigated the influence of exogenously administered melatonin on adult rats eye lenses exposed to ultraviolet radiation (UV) A and B ranging from 356-254 nm irradiation at 8 microW/cm(2). Rats exposed to this range of UV for 15 min for one week showed a significant (P<0.05) reduction in antioxidant enzymes activities; superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and elevated (P<0.001) lipid peroxidation served as an index of cellular damage by free radicals. UV-radiation significantly (P<0.001) elevated calcium ions (Ca(2+)) and lactate dehydrogenase (LDH) activity in lenses. Depleting animals of their stores of important intracellular antioxidant and elevating lenticular Ca(2+) by UV irradiation, may be the main cause of lens opacification. Melatonin injection with radiation significantly reduced (P<0.05) lipid peroxidation, Ca(2+) and (P<0.001) for LDH. When melatonin was injected after radiation, SOD and GSH-Px enzyme activities increased significantly (P<0.01), and lipid peroxidation, Ca(2+) levels and LDH activities were reduced significantly. Melatonin injection after UV radiation was as effective as melatonin treatment concurrent with UV irradiation. We conclude that melatonin may protect the eye lens from the damaging effects of UV exposure, and its actions protect lens from oxidative stress, elevating Ca(2+) levels, which are considered as an important causes of cataractogenesis.

Radiation increases the activity of oncolytic adenovirus cancer gene therapy vectors that overexpress the ADP (E3-11.6K) protein.

PubMed

Toth, Karoly; Tarakanova, Vera; Doronin, Konstantin; Ward, Peter; Kuppuswamy, Mohan; Locke, Jacob E; Dawson, Julie E; Kim, Han J; Wold, William S M

2003-03-01

We have described three potential adenovirus type 5 (Ad5)-based replication-competent cancer gene therapy vectors named KD1, KD3, and VRX-007. All three vectors overexpress an Ad5 protein named Adenovirus Death Protein (ADP, also named E3-11.6 K protein). ADP is required for efficient lysis of Ad5-infected cells and spread of virus from cell to cell, and thus its overexpression increases the oncolytic activity of the vectors. KD1 and KD3 contain mutations in the Ad5 E1A gene that knock out binding of the E1A proteins to cellular p300/CBP and pRB; these mutations allow KD1 and KD3 to grow well in cancer cells but not in normal cells. VRX-007 has wild-type E1A. Here we report that radiation increases the oncolytic activity of KD1, KD3, and VRX-007. This increased activity was observed in cultured cells, and it was not because of radiation-induced replication of the vectors. The combination of radiation plus KD3 suppressed the growth of A549 lung adenocarcinoma xenografts in nude mice more efficiently than radiation alone or KD3 alone. The combination of ADP-overexpressing vectors and radiation may have potential in treating cancer.

Extinction cross-section cancellation of a cylindrical radiating active source near a rigid corner and acoustic invisibility

NASA Astrophysics Data System (ADS)

Mitri, F. G.

2017-11-01

Active cloaking in its basic form requires that the extinction cross-section (or energy efficiency) from a radiating body vanishes. In this analysis, this physical effect is demonstrated for an active cylindrically radiating acoustic source in a non-viscous fluid, undergoing periodic axisymmetric harmonic vibrations near a rigid corner (i.e., quarter-space). The rigorous multipole expansion method in cylindrical coordinates, the method of images, and the addition theorem of cylindrical wave functions are used to derive closed-form mathematical expressions for the radiating, amplification, and extinction cross-sections of the active source. Numerical computations are performed assuming monopole and dipole modal oscillations of the circular source. The results reveal some of the situations where the extinction energy efficiency factor of the active source vanishes depending on its size and location with respect to the rigid corner, thus, achieving total invisibility. Moreover, the extinction energy efficiency factor varies between positive or negative values. These effects also occur for higher-order modal oscillations of the active source. The results find potential applications in the development of acoustic cloaking devices and invisibility in underwater acoustics or other areas.

Radiative, actively cooled panel tests results

NASA Technical Reports Server (NTRS)

Shore, C. P.; Nowak, R. J.; Sharpe, E. L.

1978-01-01

The radiative, actively cooled panel designed to withstand a uniform incident heat flux of 136 kW/sq m to a 444 K surface temperature was evaluated. The test program consisted of preliminary static thermal mechanical loading and aerothermal flow tests. Test results are briefly discussed.

Actively driven thermal radiation shield

DOEpatents

Madden, Norman W.; Cork, Christopher P.; Becker, John A.; Knapp, David A.

2002-01-01

A thermal radiation shield for cooled portable gamma-ray spectrometers. The thermal radiation shield is located intermediate the vacuum enclosure and detector enclosure, is actively driven, and is useful in reducing the heat load to mechanical cooler and additionally extends the lifetime of the mechanical cooler. The thermal shield is electrically-powered and is particularly useful for portable solid-state gamma-ray detectors or spectrometers that dramatically reduces the cooling power requirements. For example, the operating shield at 260K (40K below room temperature) will decrease the thermal radiation load to the detector by 50%, which makes possible portable battery operation for a mechanically cooled Ge spectrometer.

[Effect of Low-Intensity 900 MHz Frequency Electromagnetic Radiation on Rat Brain Enzyme Activities Linked to Energy Metabolism].

PubMed

Petrosyan, M S; Nersesova, L S; Gazaryants, M G; Meliksetyan, G O; Malakyan, M G; Bajinyan, S A; Akopian, J I

2015-01-01

The research deals with the effect of low-intensity 900 MHz frequency electromagnetic radiation (EMR), power density 25 μW/cm2, on the following rat brain and blood serum enzyme activities: creatine kinase (CK), playing a central role in the process of storing and distributing the cell energy, as well as alanine aminotransferase (ALT) and aspartate aminotransferase (AST) that play a key role in providing the conjunction of carbohydrate and amino acid metabolism. The comparative analysis of the changes in the enzyme activity studied at different times following the two-hour single, as well as fractional, radiation equivalent of the total time showed that the most radiosensitive enzyme is the brain creatine kinase, which may then be recommended as a marker of the radio frequency radiation impact. According to the analysis of the changing dynamics of the CK, ALT and AST activity level, with time these changes acquire the adaptive character and are directed to compensate the damaged cell energy metabolism.

Solar Activity, Ultraviolet Radiation and Consequences in Birds in Mexico City, 2001- 2002

NASA Astrophysics Data System (ADS)

Valdes, M.; Velasco, V.

2008-12-01

Anomalous behavior in commercial and pet birds in Mexico City was reported during 2002 by veterinarians at the Universidad Nacional Autonoma de Mexico. This was attributed to variations in the surrounding luminosity. The solar components, direct, diffuse, global, ultraviolet band A and B, as well as some meteorological parameters, temperature, relative humidity, and precipitation, were then analyzed at the Solar Radiation Laboratory. Although the total annual radiance of the previously mentioned radiation components did not show important changes, ultraviolet Band-B solar radiation did vary significantly. During 2001 the total annual irradiance , 61.05 Hjcm² to 58.32 Hjcm², was 1.6 standard deviations lower than one year later, in 2002 and increased above the mean total annual irradiance, to 65.75 Hjcm², 2.04 standard deviations, giving a total of 3.73 standard deviations for 2001-2002. Since these differences did not show up clearly in the other solar radiation components, daily extra-atmosphere irradiance was analyzed and used to calculate the total annual extra-atmosphere irradiance, which showed a descent for 2001. Our conclusions imply that Ultraviolet Band-B solar radiation is representative of solar activity and has an important impact on commercial activity related with birds.

Nuclear Countermeasure Activity of TP508 Linked to Restoration of Endothelial Function and Acceleration of DNA Repair

PubMed Central

Olszewska-Pazdrak, Barbara; McVicar, Scott D.; Rayavara, Kempaiah; Moya, Stephanie M.; Kantara, Carla; Gammarano, Chris; Olszewska, Paulina; Fuller, Gerald M.; Sower, Laurie E.; Carney, Darrell H.

2016-01-01

There is increasing evidence that radiation-induced damage to endothelial cells and loss of endothelial function may contribute to both acute radiation syndromes and long-term effects of whole-body nuclear irradiation. Therefore, several drugs are being developed to mitigate the effects of nuclear radiation, most of these drugs will target and protect or regenerate leukocytes and platelets. Our laboratory has demonstrated that TP508, a 23-amino acid thrombin peptide, activates endothelial cells and stem cells to revascularize and regenerate tissues. We now show that TP508 can mitigate radiation-induced damage to endothelial cells in vitro and in vivo. Our in vitro results demonstrate that human endothelial cells irradiation attenuates nitric oxide (NO) signaling, disrupts tube formation and induces DNA double-strand breaks (DSB). TP508 treatment reverses radiation effects on NO signaling, restores tube formation and accelerates the repair of radiation-induced DSB. The radiation-mitigating effects of TP508 on endothelial cells were also seen in CD-1 mice where systemic injection of TP508 stimulated endothelial cell sprouting from aortic explants after 8 Gy irradiation. Systemic doses of TP508 that mitigated radiation-induced endothelial cell damage, also significantly increased survival of CD-1 mice when injected 24 h after 8.5 Gy exposure. These data suggest that increased survival observed with TP508 treatment may be due to its effects on vascular and microvascular endothelial cells. Our study supports the usage of a regenerative drug such as TP508 to activate endothelial cells as a countermeasure for mitigating the effects of nuclear radiation. PMID:27388041

[The role of homeobox B2 gene in vascular endothelial proliferation and the protective effects of VEGF on the endothelia against radiation injury].

PubMed

Liu, Xu-sheng; Zhang, Xiao-qi; Liu, Liang; Ming, Jia; Xu, Hui; Ran, Xin-ze; Cheng, Tian-min

2004-10-01

To explore the role of HOXB2 gene in the proliferation of primary human umbilical vein endothelial cells (HUVECs) and the protective effects of VEGF on the endothelia against radiation injury. HUVECs were isolated, cultured, subcultured and identified. (1) Liposome coated oligodeoxynucleotide (odn) and homeoboxB2 antisense oligodeoxyncleotide (HOXB2asodn) were prepared prepared in the concentrations of 0.25, 0.5, 1.0 and 2.5 mg/L for the stimulation of HUVEC. (3)H-TdR incorporation test and MTT method were employed to determine the proliferation activity of HUVECs after activation. The cell cycle analysis of HUVECs was determined by flow cytometry. The expression level of HOXB2mRNA within HUVECs was detected by RT-PCR (reverse transcription polymerase chain reaction). (2) HUVECs were separately treated with the addition of VEGF in concentration of 50 microg/L, by radiation in the dose of 6 Gy or 12 Gy (60)Co gamma gamma ray, or radiation with 12 Gy (60)Co gamma gamma ray followed by the addition of VEGF in dose of 50 microg/L. The cellular morphology was observed and the cellular proliferation activity was determined by MTT method. (1) The proliferation activity of HUVECs could be markedly inhibited by liposome coated HOXB2asodn in comparison to liposome-odn (P < 0.05 or 0.001), and the inhibition effect was positively correlated with the increase in asodn concentration. The cell ratio in S phase and the expression level of the HOXB2mRNA could be lowered by asodn in dose of 2.5 mg/L (P < 0.05 or 0.001). (2) Radiation by (60)Co gamma ray could lead to the nuclear enlargement, vacuolation in the cytoplasm, multiplicity of nucleus and nuclear swelling. The proliferative activity of HUVECs was increased from 0.365 +/- 0.047 and 0.487 +/- 0.022 without radiation to 0.557 +/- 0.042 and 0.648 +/- 0.021 24 and 48 hours after 6 Gy radiation However it was decreased to 0.263 +/- 0.038 and 0.306 +/- 0.024 (P < 0.01) after 12 Gy (60)Co gamma ray radiation. Nevertheless, the cell morphology was obviously improved and the proliferation was enhanced by the addition of VEGF after 12 Gy radiation. HOXB2 gene played important roles in the biological activities of HUVECs. Small dose (6 Gy) gamma-radiation could promote, but large dose (12 Gy) could decrease the mRNA expression of HOXB2 gene in HUVECs. In addition, VEGF could protect HUVECs against radiation injury.

Rosiglitazone enhances the radiosensitivity of p53-mutant HT-29 human colorectal cancer cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chiu, Shu-Jun, E-mail: chiusj@mail.tcu.edu.tw; Institute of Radiation Sciences, Tzu Chi Technology College, Hualien, Taiwan; Hsaio, Ching-Hui

2010-04-09

Combined-modality treatment has improved the outcome in cases of various solid tumors, and radiosensitizers are used to enhance the radiotherapeutic efficiency. Rosiglitazone, a synthetic ligand of peroxisome proliferator-activated receptors {gamma} used in the treatment of type-2 diabetes, has been shown to reduce tumor growth and metastasis in human cancer cells, and may have the potential to be used as a radiosensitizer in radiotherapy for human colorectal cancer cells. In this study, rosiglitazone treatment significantly reduced the cell viability of p53-wild type HCT116 cells but not p53-mutant HT-29 cells. Interestingly, rosiglitazone pretreatment enhanced radiosensitivity in p53-mutant HT-29 cells but not HCT116more » cells, and prolonged radiation-induced G{sub 2}/M arrest and enhanced radiation-induced cell growth inhibition in HT-29 cells. Pretreatment with rosiglitazone also suppressed radiation-induced H2AX phosphorylation in response to DNA damage and AKT activation for cell survival; on the contrary, rosiglitazone pretreatment enhanced radiation-induced caspase-8, -9, and -3 activation and PARP cleavage in HT-29 cells. In addition, pretreatment with a pan-caspase inhibitor, zVAD-fmk, attenuated the levels of caspase-3 activation and PARP cleavage in radiation-exposed cancer cells in combination with rosiglitazone pretreatment. Our results provide proof for the first time that rosiglitazone suppresses radiation-induced survival signals and DNA damage response, and enhances the radiation-induced apoptosis signaling cascade. These findings can assist in the development of rosiglitazone as a novel radiosensitizer.« less

Alectinib induced CNS radiation necrosis in an ALK+NSCLC patient with a remote (7 years) history of brain radiation.

PubMed

Ou, Sai-Hong Ignatius; Weitz, Michael; Jalas, John R; Kelly, Daniel F; Wong, Vanessa; Azada, Michele C; Quines, Oliver; Klempner, Samuel J

2016-06-01

Alectinib is a second generation ALK inhibitor that has significant clinical activity in central nervous system (CNS) metastases in anaplastic lymphoma kinase (ALK)-rearranged non-small cell lung cancer (NSCLC). Pseudoprogression (PsP) due to radiation necrosis during alecitnib treatment of central nervous system (CNS) metastases from ALK-rearranged NSCLC as been reported. Hence, distinguishing radiation-related PsP from alectinib-induced radiographic changes is important to avoid erroneous early trial discontinuation and abandonment of an effective treatment. However, it remains difficult to assess casuality of radiation necrosis is related to recent direct radiation or induced by alectinib treatment or both. It is also unknown how long from previous radiation can alectinib still induce radiation necrosis. Here we reported a crizotinib-refractory ALK-positive NSCLC patient who develop radiation necrosis in one of his metastatic CNS lesions after approximately 12 months of alectinib treatment who otherwise had on-going CNS response on alectinib. His most recent radiation to his CNS metastases was 7 years prior to the start of alectinib. This case illustrates that in the setting of pror CNS radiation, given the significant clinical activity of alectinib in CNS metastases in ALK-positive NSCLC patients the risk of CNS radiation necrosis remains long after previous radiation to the CNS metastases has been completed and can occur after durable response of treatment. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

The DOSIS and DOSIS 3D Experiments onboard the International Space Station - Results from the Active DOSTEL Instruments

NASA Astrophysics Data System (ADS)

Burmeister, Soenke; Berger, Thomas; Reitz, Guenther; Beaujean, Rudolf; Boehme, Matthias; Haumann, Lutz; Labrenz, Johannes; Kortmann, Onno

2012-07-01

Besides the effects of the microgravity environment, and the psychological and psychosocial problems experienced in confined spaces, radiation is the main health detriment for long duration human space missions. The radiation environment encountered in space differs in nature from that on earth, consisting mostly of high energetic ions from protons up to iron, resulting in radiation levels far exceeding the ones present on earth for occupational radiation workers. Accurate knowledge of the physical characteristics of the space radiation field in dependence on the solar activity, the orbital parameters and the different shielding configurations of the International Space Station ISS is therefore needed. For the investigation of the spatial and temporal distribution of the radiation field inside the European COLUMBUS module the experiment DOSIS (Dose Distribution Inside the ISS) under the lead of DLR was launched on July 15th 2009 with STS-127 to the ISS. The experimental package was transferred from the Space Shuttle into COLUMBUS on July 18th. It consists of a combination of passive detector packages (PDP) distributed at 11 locations inside the European Columbus Laboratory and two active radiation detectors (DOSTELs) with a DDPU (DOSTEL Data and Power Unit) in a nomex pouch (DOSIS MAIN BOX) mounted at a fixed location beneath the European Physiology Module rack (EPM) inside COLUMBUS. The DOSTELs measured during the lowest solar minimum conditions in the space age from July 18th 2009 to June 16th 2011. In July 2011 the active hardware was transferred to ground for refurbishment and preparation for the DOSIS-3D experiment. The hardware will be launched with the Soyuz 30S flight to the ISS on May 15th 2012 and activated approximately ten days later. Data will be transferred from the DOSTEL units to ground via the EPM rack which is activated approximately every four weeks for this action. First Results for the active DOSIS-3D measurements such as count rate profiles, dose rates and LET spectra will be presented in comparison to the data of the DOSIS experiment as well as the DOSMAP experiment which has been performed during solar maximum in 2001.

Radiation curing progress in Hungary

NASA Astrophysics Data System (ADS)

Czvikovszky, T.

Radiation chemistry and radiation processing is an actively cultivated field of chemical technology and of applied research in several Central/Eastern European countries. Hungary, with his synthetic polymer production over 50 kg/capita/year, with his strong commitment in nuclear power production /almost 40 % of total electric power/, with his pioneering activity in food irradiation, radiation sterilization as well as EB processing of polymer — performs an iniciating role in this region. Actually four industrial EB machines are working in Hungary on plastics converting. Two of these accelerators, manufactured in SU are producing heat-shrinkable products. Two other, low-energy EB machines from FRG are working on industrial-scale surface-coating. An ELECTROCURTAIN /USA/ is serving R/D. Some actual problems of the applied radiation chemistry of EB-curing will be discussed.

Radiation hardening of rare-earth doped fiber amplifiers

NASA Astrophysics Data System (ADS)

Vivona, Marilena; Girard, Sylvain; Marcandella, Claude; Pinsard, Emmanuel; Laurent, Arnaud; Robin, Thierry; Cadier, Benoît; Cannas, Marco; Boukenter, Aziz; Ouerdane, Y.

2017-11-01

We investigated the radiation hardening of optical fiber amplifiers operating in space environments. Through a real-time analysis in active configuration, we evaluated the role of Ce in the improvement of the amplifier performance against ionizing radiations. Ce-codoping is an efficient hardening solution, acting both in the limitation of defects in the host glass matrix of RE-doped optical fibers and in the stabilization of lasing properties of the Er3+-ions. On the one hand, in the near-infrared region, radiation induced attenuation measurements show the absence of radiation induced P-related defect species in host glass matrix of the Ce-codoped active fibers; on the other hand, in the Ce-free fiber, the higher lifetime variation shows stronger local modifications around the Er3+-ions with the absence of Ce.

A semiconductor radiation imaging pixel detector for space radiation dosimetry.

PubMed

Kroupa, Martin; Bahadori, Amir; Campbell-Ricketts, Thomas; Empl, Anton; Hoang, Son Minh; Idarraga-Munoz, John; Rios, Ryan; Semones, Edward; Stoffle, Nicholas; Tlustos, Lukas; Turecek, Daniel; Pinsky, Lawrence

2015-07-01

Progress in the development of high-performance semiconductor radiation imaging pixel detectors based on technologies developed for use in high-energy physics applications has enabled the development of a completely new generation of compact low-power active dosimeters and area monitors for use in space radiation environments. Such detectors can provide real-time information concerning radiation exposure, along with detailed analysis of the individual particles incident on the active medium. Recent results from the deployment of detectors based on the Timepix from the CERN-based Medipix2 Collaboration on the International Space Station (ISS) are reviewed, along with a glimpse of developments to come. Preliminary results from Orion MPCV Exploration Flight Test 1 are also presented. Copyright © 2015 The Committee on Space Research (COSPAR). All rights reserved.

Tumor Cells Surviving Exposure to Proton or Photon Radiation Share a Common Immunogenic Modulation Signature, Rendering Them More Sensitive to T Cell–Mediated Killing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gameiro, Sofia R.; Malamas, Anthony S.; Bernstein, Michael B.

Purpose: To provide the foundation for combining immunotherapy to induce tumor antigen–specific T cells with proton radiation therapy to exploit the activity of those T cells. Methods and Materials: Using cell lines of tumors frequently treated with proton radiation, such as prostate, breast, lung, and chordoma, we examined the effect of proton radiation on the viability and induction of immunogenic modulation in tumor cells by flow cytometric and immunofluorescent analysis of surface phenotype and the functional immune consequences. Results: These studies show for the first time that (1) proton and photon radiation induced comparable up-regulation of surface molecules involved in immune recognition (histocompatibilitymore » leukocyte antigen, intercellular adhesion molecule 1, and the tumor-associated antigens carcinoembryonic antigen and mucin 1); (2) proton radiation mediated calreticulin cell-surface expression, increasing sensitivity to cytotoxic T-lymphocyte killing of tumor cells; and (3) cancer stem cells, which are resistant to the direct cytolytic activity of proton radiation, nonetheless up-regulated calreticulin after radiation in a manner similar to non-cancer stem cells. Conclusions: These findings offer a rationale for the use of proton radiation in combination with immunotherapy, including for patients who have failed radiation therapy alone or have limited treatment options.« less

Short-Course Treatment With Gefitinib Enhances Curative Potential of Radiation Therapy in a Mouse Model of Human Non-Small Cell Lung Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bokobza, Sivan M.; Jiang, Yanyan; Weber, Anika M.

2014-03-15

Purpose: To evaluate the combination of radiation and an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) in preclinical models of human non-small cell lung cancer. Methods and Materials: Sensitivity to an EGFR TKI (gefitinib) or radiation was assessed using proliferation assays and clonogenic survival assays. Effects on receptor signal transduction pathways (pEGFR, pAKT, pMAPK) and apoptosis (percentage of cleaved PARP Poly (ADP-ribose) polymerase (PARP)) were assessed by Western blotting. Radiation-induced DNA damage was assessed by γH2AX immunofluorescence. Established (≥100 mm{sup 3}) EGFR-mutated (HCC287) or EGFR wild-type (A549) subcutaneous xenografts were treated with radiation (10 Gy, day 1) or gefitinib (50 mg/kg,more » orally, on days 1-3) or both. Results: In non-small cell lung cancer (NSCLC) cell lines with activating EGFR mutations (PC9 or HCC827), gefitinib treatment markedly reduced pEGFR, pAKT, and pMAPK levels and was associated with an increase in cleaved PARP but not in γH2AX foci. Radiation treatment increased the mean number of γH2AX foci per cell but did not significantly affect EGFR signaling. In contrast, NSCLC cell lines with EGFR T790M (H1975) or wild-type EGFR (A549) were insensitive to gefitinib treatment. The combination of gefitinib and radiation treatment in cell culture produced additive cell killing with no evidence of synergy. In xenograft models, a short course of gefitinib (3 days) did not significantly increase the activity of radiation treatment in wild-type EGFR (A549) tumors (P=.27), whereas this combination markedly increased the activity of radiation (P<.001) or gefitinib alone (P=.002) in EGFR-mutated HCC827 tumors, producing sustained tumor regressions. Conclusions: Gefitinib treatment increases clonogenic cell killing by radiation but only in cell lines sensitive to gefitinib alone. Our data suggest additive rather than synergistic interactions between gefitinib and radiation and that a combination of short-course gefitinib and high-dose/-fraction radiation may have the greatest potential against the subsets of lung cancers harboring activating mutations in the EGFR gene.« less

Evaluation of Delivery Costs for External Beam Radiation Therapy and Brachytherapy for Locally Advanced Cervical Cancer Using Time-Driven Activity-Based Costing.

PubMed

Bauer-Nilsen, Kristine; Hill, Colin; Trifiletti, Daniel M; Libby, Bruce; Lash, Donna H; Lain, Melody; Christodoulou, Deborah; Hodge, Constance; Showalter, Timothy N

2018-01-01

To evaluate the delivery costs, using time-driven activity-based costing, and reimbursement for definitive radiation therapy for locally advanced cervical cancer. Process maps were created to represent each step of the radiation treatment process and included personnel, equipment, and consumable supplies used to deliver care. Personnel were interviewed to estimate time involved to deliver care. Salary data, equipment purchasing information, and facilities costs were also obtained. We defined the capacity cost rate (CCR) for each resource and then calculated the total cost of patient care according to CCR and time for each resource. Costs were compared with 2016 Medicare reimbursement and relative value units (RVUs). The total cost of radiation therapy for cervical cancer was $12,861.68, with personnel costs constituting 49.8%. Brachytherapy cost $8610.68 (66.9% of total) and consumed 423 minutes of attending radiation oncologist time (80.0% of total). External beam radiation therapy cost $4055.01 (31.5% of total). Personnel costs were higher for brachytherapy than for the sum of simulation and external beam radiation therapy delivery ($4798.73 vs $1404.72). A full radiation therapy course provides radiation oncologists 149.77 RVUs with intensity modulated radiation therapy or 135.90 RVUs with 3-dimensional conformal radiation therapy, with total reimbursement of $23,321.71 and $16,071.90, respectively. Attending time per RVU is approximately 4-fold higher for brachytherapy (5.68 minutes) than 3-dimensional conformal radiation therapy (1.63 minutes) or intensity modulated radiation therapy (1.32 minutes). Time-driven activity-based costing was used to calculate the total cost of definitive radiation therapy for cervical cancer, revealing that brachytherapy delivery and personnel resources constituted the majority of costs. However, current reimbursement policy does not reflect the increased attending physician effort and delivery costs of brachytherapy. We hypothesize that the significant discrepancy between treatment costs and physician effort versus reimbursement may be a potential driver of reported national trends toward poor compliance with brachytherapy, and we suggest re-evaluation of payment policies to incentivize quality care. Copyright © 2017 Elsevier Inc. All rights reserved.

Active personal radiation monitor for lunar EVA

NASA Astrophysics Data System (ADS)

Straume, Tore; Borak, Tom; Braby, L. A.; Lusby, Terry; Semones, Edward J.; Vazquez, Marcelo E.

As astronauts return to the Moon-and this time, work for extended periods-there will be a critical need for crew personnel radiation monitoring as they operate lunar rovers or otherwise perform a myriad of extravehicular activities (EVAs). Our focus is on development of a small personal radiation monitor for lunar EVA that responds to the complex radiation quality and changing dose rates on the Moon. Of particular concern are active monitoring capabilities that provide both early warning and radiation dosimetry information during solar particle events (SPEs). To accomplish this, we are developing small detectors integrated with modern high speed, low power microelectronics to measure dose-rate and dose-mean lineal energy in real time. The monitor is designed to perform over the range of dose rates and LETs expected from both GCR and SPE radiations during lunar EVA missions. The monitor design provides simultaneous measurement of dose-equivalent rates at two tissue-equivalent depths simulating skin and marrow. The compact personal monitor is estimated to be the size of a cell phone and would fit on an EVA spacesuit (e.g., in backpack) or in a toolbox. The four-year development effort (which began December 2007) will result in a prototype radiation monitor field tested and characterized for the major radiations expected on the surface of the Moon. We acknowledge support from NSBRI through grants to NASA Ames Research Center (T. Straume, PI) and Colorado State University (T. Borak, PI).

75 FR 28803 - Agency Information Collection Activities; Submission to OMB for Review and Approval; Comment...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-24

... INFORMATION CONTACT: Charles M. Petko, Office of Radiation and Indoor Air (ORIA), National Air and Radiation... Protection Agency, Air and Radiation Docket, Mail Code 28221T, 1200 Pennsylvania Ave., NW., Washington, DC... viewing at the Office of Air and Radiation Docket in the EPA Docket Center (EPA/DC), EPA West, Room 3334...

Evaluation of fraction of absorbed photosynthetically active radiation products for different canopy radiation transfer regimes: methodology and results using Joint Research Center products derived from SeaWiFS against ground-based estimations.

Treesearch

Nadine Gobron; Bernard Pinty; Ophélie Aussedat; Jing M. Chen; Warren B. Cohen; Rasmus Fensholt; Valery Gond; Karl Fred Huemmrich; Thomas Lavergne; Frédéric Méline; Jeffrey L. Privette; Inge Sandholt; Malcolm Taberner; David P. Turner; Michael M. Verstraete; Jean-Luc Widlowski

2006-01-01

This paper discusses the quality and the accuracy of the Joint Research Center (JRC) fraction of absorbed photosynthetically active radiation (FAPAR) products generated from an analysis of Sea-viewing Wide Field-of-view Sensor (SeaWiFS) data. The FAPAR value acts as an indicator of the presence and state of the vegetation and it can be estimated from remote sensing...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Shih-Yew; Napier, Bruce A.

The Program Area Committee 5 (PAC 5) of the National Council on Radiation protection and Measurements (NCRP) focuses its activities on environmental radiation and radioactive waste issues. The committee completed a number of reports in the subject areas, and specifically the most recent NCRP Report 175 (Decision Making for Late-Phase Recovery from Major Nuclear or Radiological Incidents). Historically PAC 5 addressed the emerging issues of the nation that pertain to radioactivity or radiation in the environment, or the radioactive waste issues due either to the natural origins or to the manmade activities

Traceability of radiation protection instruments

NASA Astrophysics Data System (ADS)

Hino, Y.; Kurosawa, T.

2007-08-01

Radiation protection instruments are used in daily measurement of dose and activities in workplaces and environments for safety management. The requirements for calibration certificates with traceability are increasing for these instruments to ensure the consistency and reliabilities of the measurement results. The present traceability scheme of radiation protection instruments for dose and activity measurements is described with related IEC/ISO requirements. Some examples of desirable future calibration systems with recent new technologies are also discussed to establish the traceability with reasonable costs and reliabilities.

[Effect of NF-κB activation on the radiation response of esophageal cancer cells].

PubMed

Li, Baozhong; Chen, Zhaoli; Zhou, Fang; He, Jie

2014-07-01

To investigate the effect of NF-κB activation on radiation response of esophageal carcinoma. The expression of NF-κB was detected in pretreatment and posttreatment specimens of patients with ESCC by immunohistochemistry. Electrophoretic mobility shift assay (EMSA) and Western blot were used to detect the activation of NF-κB in esophageal cancer cell line KYSE150 cells. SN50, a specific NF-κB inhibitor, was applied to inhibit the activation of NF-κB. Clone formation test was used to detect the radiosensitivity of esophageal cancer cells. The median survival time of patients with activated and inactivated NF-κB in the pretreatment specimens were 16 and 19 months, respectively, with a non-significant difference between the two groups (P > 0.05). As to the patients with activated and inactivated NF-κB in posttreatment specimens, the median survival times were 13 and 35 months, respectively, with a significant difference (P < 0.01) between them. Western blot showed that the cytoplasmic expression of NF-κB was reduced with increasing radiation dose at 1.5 and 3 hours after radiation treatment. However, the expression of NF-κB in the cell nuclei was increased under the same condition, showing a trend of increased nucleus/cytoplasm ratio. The clone number in SN50 group was 96.66, 64.66, 76.66 and 10.00 under 0, 2, 4 and 12 Gy irradiation, which demonstrated a significant difference compared with the control groups (P < 0.001). Our results show that activation of NF-κB is induced by radiotherapy. Activation of NF-κB reduces the outcome of radiation treatment of esophageal cancer patients.

Activating Photodynamic Therapy in vitro with Cerenkov Radiation Generated from Yttrium-90

PubMed Central

Hartl, Brad A.; Hirschberg, Henry; Marcu, Laura; Cherry, Simon R.

2017-01-01

The translation of photodynamic therapy (PDT) to the clinical setting has primarily been limited to easily accessible and/or superficial diseases, for which traditional light delivery can be performed noninvasively. Cerenkov radiation, as generated from medically relevant radionuclides, has been suggested as a means to deliver light to deeper tissues noninvasively to overcome this depth limitation. This article investigates the utility of Cerenkov radiation, as generated from the radionuclide yttrium-90, for activating the PDT process using clinically approved aminolevulinic acid at 1.0 mm and also the more efficient porphyrin-based photosensitizer mesotetraphenylporphine with two sulfonate groups on adjacent phenyl rings (TPPS2a) at 1.2 μM. Experiments were conducted with monolayer cultured glioma and breast tumor cell lines. Although aminolevulinic acid proved to be ineffective for generating a therapeutic effect at all but the highest activity levels, TPPS2a produced at least a 20% therapeutic effect at activities ranging from 6 to 60 μCi/well for the C6 glioma cell line. Importantly, these results demonstrate for the first time, to our knowledge, that Cerenkov radiation generated from a radionuclide can be used to activate PDT using clinically relevant photosensitizers. These results therefore provide evidence that it may be possible to generate a phototherapeutic effect in vivo using Cerenkov radiation and clinically relevant photosensitizers. PMID:27481495

Optically Activated Exciplex Shutter/Attenuator.

DTIC Science & Technology

radiation of a certain wavelength to excite a bi-molecular exciplex solution. The exciplex solution reacts to a range of radiation wavelengths whereas...optical elements prevent passage of radiation below and above the operative range of an exciplex solution such as anthracene and diethylaniline.

10 CFR 835.1 - Scope.

Code of Federal Regulations, 2010 CFR

2010-01-01

... OCCUPATIONAL RADIATION PROTECTION General Provisions § 835.1 Scope. (a) General. The rules in this part establish radiation protection standards, limits, and program requirements for protecting individuals from ionizing radiation resulting from the conduct of DOE activities. (b) Exclusion. Except as provided in...

Exploiting different active silicon detectors in the International Space Station: ALTEA and DOSTEL galactic cosmic radiation (GCR) measurements

NASA Astrophysics Data System (ADS)

Narici, Livo; Berger, Thomas; Burmeister, Sönke; Di Fino, Luca; Rizzo, Alessandro; Matthiä, Daniel; Reitz, Günther

2017-08-01

The solar system exploration by humans requires to successfully deal with the radiation exposition issue. The scientific aspect of this issue is twofold: knowing the radiation environment the astronauts are going to face and linking radiation exposure to health risks. Here we focus on the first issue. It is generally agreed that the final tool to describe the radiation environment in a space habitat will be a model featuring the needed amount of details to perform a meaningful risk assessment. The model should also take into account the shield changes due to the movement of materials inside the habitat, which in turn produce changes in the radiation environment. This model will have to undergo a final validation with a radiation field of similar complexity. The International Space Station (ISS) is a space habitat that features a radiation environment inside which is similar to what will be found in habitats in deep space, if we use measurements acquired only during high latitude passages (where the effects of the Earth magnetic field are reduced). Active detectors, providing time information, that can easily select data from different orbital sections, are the ones best fulfilling the requirements for these kinds of measurements. The exploitation of the radiation measurements performed in the ISS by all the available instruments is therefore mandatory to provide the largest possible database to the scientific community, to be merged with detailed Computer Aided Design (CAD) models, in the quest for a full model validation. While some efforts in comparing results from multiple active detectors have been attempted, a thorough study of a procedure to merge data in a single data matrix in order to provide the best validation set for radiation environment models has never been attempted. The aim of this paper is to provide such a procedure, to apply it to two of the most performing active detector systems in the ISS: the Anomalous Long Term Effects in Astronauts (ALTEA) instrument and the DOSimetry TELescope (DOSTEL) detectors, applied in the frame of the DOSIS and DOSIS 3D project onboard the ISS and to present combined results exploiting the features of each of the two apparatuses.

Austrian results from Matroshka poncho and organ dose determination

NASA Astrophysics Data System (ADS)

Hajek, M.; Bergmann, R.; Fugger, M.; Vana, N.

Cosmic rays in low-earth orbits LEO primarily consist of high-energy charged particles originating from galactic cosmic radiation GCR energetic solar particle events SPE and trapped radiation belts These radiations of high linear energy transfer LET generally inflict greater biological damage than that resulting from typical terrestrial radiation hazards Particle and energy spectra are attenuated in interaction processes within shielding structures and within the human body Reliable assessment of health risks to astronaut crews is pivotal in the design of future expeditions into interplanetary space and requires knowledge of absorbed radiation doses in critical radiosensitive organs and tissues The European Space Agency ESA Matroshka experiment---conducted under the aegis of the German Aerospace Center DLR ---is aimed at simulating an astronaut s body during extravehicular activities EVA Matroshka basically consists of a human phantom torso attached to a base structure and covered with a protective carbon-fibre container acting as a spacesuit model The phantom is divided into 33 tissue-equivalent polyurethane slices of specific density for tissue and organs Natural bones are embedded Channels and cut-outs enable accommodation of active and passive radiation monitors The torso is dressed by a skin-equivalent poncho which is also designed for dosimeter integration The phantom houses in total 7 active and more than 6000 passive radiation sensors Thereof the Atomic Institute of the Austrian Universities ATI provided more than

Improving Quality and Access to Radiation Therapy-An IAEA Perspective.

PubMed

Abdel-Wahab, May; Zubizarreta, Eduardo; Polo, Alfredo; Meghzifene, Ahmed

2017-04-01

The International Atomic Energy Agency (IAEA) has been involved in radiation therapy since soon after its creation in 1957. In response to the demands of Member States, the IAEA׳s activities relating to radiation therapy have focused on supporting low- and middle-income countries to set up radiation therapy facilities, expand the scope of treatments, or gradually transition to new technologies. In addition, the IAEA has been very active in providing internationally harmonized guidelines on clinical, dosimetry, medical physics, and safety aspects of radiation therapy. IAEA clinical research has provided evidence for treatment improvement as well as highly effective resource-sparing interventions. In the process, training of researchers occurs through this program. To provide this support, the IAEA works with its Member States and multiple partners worldwide through several mechanisms. In this article, we review the main activities conducted by the IAEA in support to radiation therapy. IAEA support has been crucial for achieving tangible results in many low- and middle-income countries. However, long-term sustainability of projects can present a challenge, especially when considering health budget constraints and the brain drain of skilled professionals. The need for support remains, with more than 90% of patients in low-income countries lacking access to radiotherapy. Thus, the IAEA is expected to continue its support and strengthen quality radiation therapy treatment of patients with cancer. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

UV Radiation Activates Toll-Like Receptor 9 Expression in Primary Human Keratinocytes, an Event Inhibited by Human Papillomavirus 38 E6 and E7 Oncoproteins.

PubMed

Pacini, Laura; Ceraolo, Maria Grazia; Venuti, Assunta; Melita, Giusi; Hasan, Uzma A; Accardi, Rosita; Tommasino, Massimo

2017-10-01

Several lines of evidence indicate that cutaneous human papillomavirus (HPV) types belonging to the beta genus of the HPV phylogenetic tree synergize with UV radiation in the development of skin cancer. Accordingly, the E6 and E7 oncoproteins from some beta HPV types are able to deregulate pathways related to immune response and cellular transformation. Toll-like receptor 9 (TLR9), in addition to playing a role in innate immunity, has been shown to be involved in the cellular stress response. Using primary human keratinocytes as experimental models, we have shown that UV irradiation (and other cellular stresses) activates TLR9 expression. This event is closely linked to p53 activation. Silencing the expression of p53 or deleting its encoding gene affected the activation of TLR9 expression after UV irradiation. Using various strategies, we have also shown that the transcription factors p53 and c-Jun are recruited onto a specific region of the TLR9 promoter after UV irradiation. Importantly, the E6 and E7 oncoproteins from beta HPV38, by inducing the accumulation of the p53 antagonist ΔNp73α, prevent the UV-mediated recruitment of these transcription factors onto the TLR9 promoter, with subsequent impairment of TLR9 gene expression. This study provides new insight into the mechanism that mediates TLR9 upregulation in response to cellular stresses. In addition, we show that HPV38 E6 and E7 are able to interfere with this mechanism, providing another explanation for the possible cooperation of beta HPV types with UV radiation in skin carcinogenesis. IMPORTANCE Beta HPV types have been suggested to act as cofactors in UV-induced skin carcinogenesis by altering several cellular mechanisms activated by UV radiation. We show that the expression of TLR9, a sensor of damage-associated molecular patterns produced during cellular stress, is activated by UV radiation in primary human keratinocytes (PHKs). Two transcription factors known to be activated by UV radiation, p53 and c-Jun, play key roles in UV-activated TLR9 expression. The E6 and E7 oncoproteins from beta HPV38 strongly inhibit UV-activated TLR9 expression by preventing the recruitment of p53 and c-Jun to the TLR9 promoter. Our findings provide additional support for the role that beta HPV types play in skin carcinogenesis by preventing activation of specific pathways upon exposure of PHKs to UV radiation. Copyright © 2017 American Society for Microbiology.

Estimated Internal and External Radiation Exposure of Caregivers of Patients With Pediatric Neuroblastoma Undergoing 131I Metaiodobenzylguanidine Therapy: A Prospective Pilot Study.

PubMed

Han, Sangwon; Yoo, Seon Hee; Koh, Kyung-Nam; Lee, Jong Jin

2017-04-01

Current recommendations suggest that family members should participate in the care of children receiving in-hospital I metaiodobenzylguanidine (MIBG) therapy for neuroblastoma. The present study aimed to measure the external radiation exposure and estimate the internal radiation exposure of caregivers during the hospital stay for I MIBG therapy. Caregivers received radiation safety instructions and a potassium iodide solution for thyroid blockade before patient admission. External radiation exposure was determined using a personal pocket dosimeter. Serial 24-hour urine samples were collected from caregivers during the hospital stay. Estimated internal radiation exposure was calculated based on the urine activity. Twelve cases (mean age, 6.2 ± 3.5 years; range, 2-13 years) were enrolled. The mean administered activity was 233.3 ± 74.9 (range, 150.0-350.0) mCi. The mean external radiation dose was 5.8 ± 7.2 (range, 0.8-19.9) mSv. Caregivers of children older than 4 years had significantly less external radiation exposure than those of children younger than 4 years (1.9 ± 1.0 vs 16.4 ± 5.0 mSv; P = 0.012). The mean estimated internal radiation dose was 11.3 ± 10.2 (range, 1.0-29.8) μSv. Caregivers receive both external and internal radiation exposure while providing in-hospital care to children receiving I MIBG therapy for neuroblastoma. However, the internal radiation exposure was negligible compared with the external radiation exposure.

Study of the surface activation of ETFE by low energy (keV) Si and N bombardment

NASA Astrophysics Data System (ADS)

Parada, M. A.; de Almeida, A.; Muntele, C.; Muntele, I.; Delalez, N.; Ila, D.

2005-12-01

The ethylenetetrafluoroethylene (ETFE) is a polymer formed by alternating ethylene and tetrafluoroethylene segments. It can be applied in the field of medical physics as intra venous catheters and as radiation dosimeters. The increasing application of polymeric materials in technological and scientific fields has motivated the use of surface treatments to modify the physical and chemical properties of polymer surfaces. When a material is exposed to ionizing radiation, it suffers damage leading to surface activation depending on the type, energy and intensity of the applied radiation. In order to determine the radiation damage and the surface activation mechanism ETFE films were bombarded with keV Si and N at various fluences. The bombarded film was also analyzed with optical absorption photospectrometry (OAP), Raman and Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy showing quantitatively the chemical nature at the damage caused by the Si and N bombardment.

Simulation and experimental measurement of radon activity using a multichannel silicon-based radiation detector.

PubMed

Ozdemir, F B; Selcuk, A B; Ozkorucuklu, S; Alpat, A B; Ozdemir, T; Ӧzek, N

2018-05-01

In this study, high-precision radiation detector (HIPRAD), a new-generation semiconductor microstrip detector, was used for detecting radon (Rn-222) activity. The aim of this study was to detect radon (Rn-222) activity experimentally by measuring the energy of particles in this detector. Count-ADC channel, eta-charge, and dose-response values were experimentally obtained using HIPRAD. The radon simulation in the radiation detector was theoretically performed using the Geant4 software package. The obtained radioactive decay, energy generation, energy values, and efficiency values of the simulation were plotted using the root program. The new-generation radiation detector proved to have 95% reliability according to the obtained dose-response graphs. The experimental and simulation results were found to be compatible with each other and with the radon decays and literature studies. Copyright © 2018 Elsevier Ltd. All rights reserved.

A mechanistic model of environmental oxygen influence on the deterministic effects to human skin from space radiations

NASA Astrophysics Data System (ADS)

Flores-McLaughlin, John

During human spaceflight missions, controlled variation of atmospheric pressure and oxygen concentration from a sea-level based normal to hyperoxic levels may occur as part of operational procedure. This activity is of interest because it provides the relevant radiation exposure and dynamic oxygen concentration parameters that may lead to varying radiation sensitivity in the skin and other organs. Tumor hypoxia has been indicated as a primary factor in the decrease in efficacy of radiation therapy. These oxygen concentration effects have been largely demonstrated with low-LET radiations and to a lesser degree with high-LET primary radiations such as protons and heavy ions common in space exposure. In order to analyze the variation of oxygen concentration in human skin from spaceflight activities, a mathematical model of oxygen transport through the human cardiorespiratory system with pulmonary and cutaneous intake was implemented. Oxygen concentration was simulated at the various skin layers, from dermis to epidermis. Skin surface radiation doses and spectra from relatively high flux Solar Particle Events (SPEs) were calculated by the PHITS radiation transport code over a range of spacecraft and spacesuit thicknesses in terms of aluminum equivalence. A series of anatomical skin and shielding thicknesses were chosen to encompass the scope of radiation exposure levels as indicated by existing NASA skin phantom studies. To model the influence of oxygen with radiation exposure, microdosimetric oxygen fixation simulations were implemented using the Monte-Carlo-Damage-Simulation (MCDS) code. From these outputs, occurrence of DNA double strand breaks (DSBs) and relative biological effect (RBE) from radiation exposure with oxygen concentration dependence was established and correlated to spaceflight activities. It was determined that minimal but observable oxygen concentration transients occur in skin during environmental oxygen changes in spaceflight. The most significant transients occurred in the thickest epidermal layers with relatively high amounts of diffusion. Accordingly, these thickest epidermal layers also showed the greatest spaceflight induced transients of RBE relative to sea-level based atmosphere exposures.

Greenhouse Effect, Radiative Forcing and Climate Sensitivity

NASA Astrophysics Data System (ADS)

Ponater, Michael; Dietmüller, Simone; Sausen, Robert

Temperature conditions and climate on Earth are controlled by the balance between absorbed solar radiation and outgoing terrestrial radiation. The greenhouse effect is a synonym for the trapping of infrared radiation by radiatively active atmospheric constituents. It generally causes a warming of the planet's surface, compared to the case without atmosphere. Perturbing the radiation balance of the planet, e.g., by anthropogenic greenhouse gas emissions, induces climate change. Individual contributions to a total climate impact are usually quantified and ranked in terms of their respective radiative forcing. This method involves some limitations, because the effect of the external forcing is modified by radiative feedbacks. Here the current concept of radiative forcing and potential improvements are explained.

Thermal Performance of Orion Active Thermal Control System With Seven-Panel Reduced-Curvature Radiator

NASA Technical Reports Server (NTRS)

Wang, Xiao-Yen J.; Yuko, James R.

2010-01-01

The active thermal control system (ATCS) of the crew exploration vehicle (Orion) uses radiator panels with fluid loops as the primary system to reject heat from spacecraft. The Lockheed Martin (LM) baseline Orion ATCS uses eight-panel radiator coated with silver Teflon coating (STC) for International Space Station (ISS) missions, and uses seven-panel radiator coated with AZ 93 white paint for lunar missions. As an option to increase the radiator area with minimal impact on other component locations and interfaces, the reduced-curvature (RC) radiator concept was introduced and investigated here for the thermal perspective. Each RC radiator panel has 15 percent more area than each Lockheed Martin (LM) baseline radiator panel. The objective was to determine if the RC seven-panel radiator concept could be used in the ATCS for both ISS and lunar missions. Three radiator configurations the LM baseline, an RC seven-panel radiator with STC, and an RC seven-panel radiator with AZ 93 coating were considered in the ATCS for ISS missions. Two radiator configurations the LM baseline and an RC seven-panel radiator with AZ 93 coating were considered in the ATCS for lunar missions. A Simulink/MATLAB model of the ATCS was used to compute the ATCS performance. Some major hot phases on the thermal timeline were selected because of concern about the large amount of water sublimated for thermal topping. It was concluded that an ATCS with an RC seven-panel radiator could be used for both ISS and lunar missions, but with two different coatings STC for ISS missions and AZ 93 for lunar missions to provide performance similar to or better than that of the LM baseline ATCS.

Acute radiation impacts contractility of guinea-pig bladder strips affecting mucosal-detrusor interactions.

PubMed

McDonnell, Bronagh M; Buchanan, Paul J; Prise, Kevin M; McCloskey, Karen D

2018-01-01

Radiation-induced bladder toxicity is associated with radiation therapy for pelvic malignancies, arising from unavoidable irradiation of neighbouring normal bladder tissue. This study aimed to investigate the acute impact of ionizing radiation on the contractility of bladder strips and identify the radiation-sensitivity of the mucosa vs the detrusor. Guinea-pig bladder strips (intact or mucosa-free) received ex vivo sham or 20Gy irradiation and were studied with in vitro myography, electrical field stimulation and Ca2+-fluorescence imaging. Frequency-dependent, neurogenic contractions in intact strips were reduced by irradiation across the force-frequency graph. The radiation-difference persisted in atropine (1μM); subsequent addition of PPADs (100μM) blocked the radiation effect at higher stimulation frequencies and decreased the force-frequency plot. Conversely, neurogenic contractions in mucosa-free strips were radiation-insensitive. Radiation did not affect agonist-evoked contractions (1μM carbachol, 5mM ATP) in intact or mucosa-free strips. Interestingly, agonist-evoked contractions were larger in irradiated mucosa-free strips vs irradiated intact strips suggesting that radiation may have unmasked an inhibitory mucosal element. Spontaneous activity was larger in control intact vs mucosa-free preparations; this difference was absent in irradiated strips. Spontaneous Ca2+-transients in smooth muscle cells within tissue preparations were reduced by radiation. Radiation affected neurogenic and agonist-evoked bladder contractions and also reduced Ca2+-signalling events in smooth muscle cells when the mucosal layer was present. Radiation eliminated a positive modulatory effect on spontaneous activity by the mucosa layer. Overall, the findings suggest that radiation impairs contractility via mucosal regulatory mechanisms independent of the development of radiation cystitis.

Depression of p53-independent Akt survival signals in human oral cancer cells bearing mutated p53 gene after exposure to high-LET radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nakagawa, Yosuke; Takahashi, Akihisa; Kajihara, Atsuhisa

Highlights: Black-Right-Pointing-Pointer High-LET radiation induces efficiently apoptosis regardless of p53 gene status. Black-Right-Pointing-Pointer We examined whether high-LET radiation depresses the Akt-survival signals. Black-Right-Pointing-Pointer High-LET radiation depresses of survival signals even in the mp53 cancer cells. Black-Right-Pointing-Pointer High-LET radiation activates Caspase-9 through depression of survival signals. Black-Right-Pointing-Pointer High-LET radiation suppresses cell growth through depression of survival signals. -- Abstract: Although mutations and deletions in the p53 tumor suppressor gene lead to resistance to low linear energy transfer (LET) radiation, high-LET radiation efficiently induces cell lethality and apoptosis regardless of the p53 gene status in cancer cells. Recently, it has been suggestedmore » that the induction of p53-independent apoptosis takes place through the activation of Caspase-9 which results in the cleavage of Caspase-3 and poly (ADP-ribose) polymerase (PARP). This study was designed to examine if high-LET radiation depresses serine/threonine protein kinase B (PKB, also known as Akt) and Akt-related proteins. Human gingival cancer cells (Ca9-22 cells) harboring a mutated p53 (mp53) gene were irradiated with 2 Gy of X-rays or Fe-ion beams. The cellular contents of Akt-related proteins participating in cell survival signaling were analyzed with Western Blotting 1, 2, 3 and 6 h after irradiation. Cell cycle distributions after irradiation were assayed with flow cytometric analysis. Akt-related protein levels decreased when cells were irradiated with high-LET radiation. High-LET radiation increased G{sub 2}/M phase arrests and suppressed the progression of the cell cycle much more efficiently when compared to low-LET radiation. These results suggest that high-LET radiation enhances apoptosis through the activation of Caspase-3 and Caspase-9, and suppresses cell growth by suppressing Akt-related signaling, even in mp53 bearing cancer cells.« less

Simultaneous SMM flat crystal spectrometer and Very Large Array observations of solar active regions

NASA Technical Reports Server (NTRS)

Lang, Kenneth R.; Willson, Robert F.; Smith, Kermit L.; Strong, Keith T.

1987-01-01

High-resolution images of the quiescent emission from two solar active regions at 20 cm (VLA) and soft X-ray (SMM FCS) wavelengths are compared. There are regions where the X-ray coronal loops have been completely imaged at 20 cm wavelength. In other regions, the X-ray radiation was detected without detectable 20 cm radiation, and vice versa. The X-ray data were used to infer average electron temperatures of about 3-million K and average electron densities of about 2.5 x 10 to the 9th/cu cm for the X-ray emitting plasma in the two active regions. The thermal bremsstrahlung of the X-ray emitting plasma is optically thin at 20 cm wavelength. The 20 cm brightness temperatures were always less than T(e), which is consistent with optically thin bremsstrahlung. The low T(B) can be explained if a higher, cooler plasma covers the hotter X-ray emitting plasma. Thermal gyroresonance radiation must account for the intense 20 cm radiation near and above sunspots where no X-ray radiation is detected.

Effect of ionizing radiation on the physiological activities of ethanol extract from hizikia fusiformis cooking drips.

PubMed

Kim, Hyun-Joo; Choi, Jong-il; Kim, Duk-Jin; Kim, Jae-Hun; Soo Chun, Byeong; Hyun Ahn, Dong; Sun Yook, Hong; Byun, Myung-Woo; Kim, Mi-Jung; Shin, Myung-Gon; Lee, Ju-Woon

2009-01-01

Although the byproduct from Hizikia fusiformis industry had many nutrients, it is being wasted. In this study, the physiological activities of cooking drip extracts from H. fusiformis (CDHF) were determined to investigate the effect of a gamma and an electron beam irradiations. DPPH radical scavenging activity and tyrosinase and ACE inhibition effects of the gamma and electron beam irradiated CDHF extracts were increased with increasing irradiation dose. These were reasoned by the increase in the content of the total polyphenolic compound of CDHF by the gamma and electron beam irradiation. There were no differences for the radiation types. These results show that ionizing radiation could be used for enhancing the functional activity of CDHF which is a major by-product in Hizikia fusiformis processing, in various applications.

Results of neutron irradiation of GEM detector for plasma radiation detection

NASA Astrophysics Data System (ADS)

Jednorog, S.; Bienkowska, B.; Chernyshova, M.; Łaszynska, E.; Prokopowicz, R.; Ziołkowski, A.

2015-09-01

The detecting devices dedicated for plasma monitoring will be exposed for massive fluxes of neutron, photons as well as other rays that are components of fusion reactions and their product interactions with plasma itself or surroundings. In result detecting module metallic components will be activated becoming a source of radiation. Moreover, electronics components could change their electronic properties. The prototype GEM detector constructed for monitoring soft X-ray radiation in ITER oriented tokamaks was used for plasma monitoring during experimental campaign on tokamak ASDEX Upgrade. After that it became a source of gamma radiation caused by neutrons. The present work contains description of detector activation in the laboratory conditions.

Cyclotron Line in Solar Microwave Radiation by Radio Telescope RATAN-600 Observations of the Solar Active Region NOAA 12182

NASA Astrophysics Data System (ADS)

Peterova, N. G.; Topchilo, N. A.

2017-12-01

This paper presents the results of observation of a rare phenomenon—a narrowband increase in the brightness of cyclotron radiation of one of the structural details of a radio source located in the solar corona above the solar active region NOAA 12182 in October 2014 at a frequency of 4.2 ± 0.1 GHz. The brightness of radiation in the maximum of the phenomenon has reached 10 MK; its duration was equal to 3 s. The exact location of the source of the narrowband cyclotron radiation is indicated: it is a corona above a fragmented (4-nuclear) sunspot, on which a small UV flare loop was closed.

DIRECT AND INDIRECT BIOLOGICAL EFFECTS OF RADIATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hobitz, H.

1961-01-01

The primary physical processes, ionization and excitation, induced by radiation in biological materials are discussed. Their effects in causing reduction, decarboxylation, and depolymerization in proteins and deoxyribonucleic acid of the cell nucleus are examined. The action of radiation doses of 100,000- 600,000 r on pollen of Digitalis purpurea maintained at room temperature and at approximates 190 deg C showed that biological activity was destroyed by doses >200,000 r at room temperature, but at approximates 190 deg the pollen retained some activity even after the highest dose. A similar effect was seen with Bacterium cadaveris cells, about 0.5% of which survivedmore » 50000 r given at l8O deg whereas no cells survived 20000 r given at 4 deg . The presence of 1% cysteamine at the higher temperature increased survival 20-fold. Cytochrome c showed markedly different responses to radiation in dry form as compared with aqueous solution. The anhydrous enzyme showed a linear decline in log activity with radiation dose but in aqueous solution the activity declined more slowly at higher doses. The radiation dose to-produce 50% inactivation was 4 x 10/sup 7/ r in dry form and 6 x 10/sup 5/ r in solution, a 67-fold difference. The results suggest that diffusion of the free radicals (H: or OH:) produced in the primary process is considerably hindered at low temperature and by the absence of water. (H.H.D.)« less

The MCART radiation physics core: the quest for radiation dosimetry standardization.

PubMed

Kazi, Abdul M; MacVittie, Thomas J; Lasio, Giovanni; Lu, Wei; Prado, Karl L

2014-01-01

Dose-related radiobiological research results can only be compared meaningfully when radiation dosimetry is standardized. To this purpose, the National Institute of Allergy and Infectious Diseases (NIAID)-sponsored Medical Countermeasures Against Radiological Threats (MCART) consortium recently created a Radiation Physics Core (RPC) as an entity to assume responsibility of standardizing radiation dosimetry practices among its member laboratories. The animal research activities in these laboratories use a variety of ionizing photon beams from several irradiators such as 250-320 kVp x-ray generators, Cs irradiators, Co teletherapy machines, and medical linear accelerators (LINACs). In addition to this variety of sources, these centers use a range of irradiation techniques and make use of different dose calculation schemes to conduct their experiments. An extremely important objective in these research activities is to obtain a Dose Response Relationship (DRR) appropriate to their respective organ-specific models of acute and delayed radiation effects. A clear and unambiguous definition of the DRR is essential for the development of medical countermeasures. It is imperative that these DRRs are transparent between centers. The MCART RPC has initiated the establishment of standard dosimetry practices among member centers and is introducing a Remote Dosimetry Monitoring Service (RDMS) to ascertain ongoing quality assurance. This paper will describe the initial activities of the MCART RPC toward implementing these standardization goals. It is appropriate to report a summary of initial activities with the intent of reporting the full implementation at a later date.

Inflammatory biomarkers and fatigue during radiation therapy for breast and prostate cancer.

PubMed

Bower, Julienne E; Ganz, Patricia A; Tao, May Lin; Hu, Wenhua; Belin, Thomas R; Sepah, Saviz; Cole, Steve; Aziz, Najib

2009-09-01

Biomarkers of radiation-induced behavioral symptoms, such as fatigue, have not been identified. Studies linking inflammatory processes to fatigue in cancer survivors led us to test the hypothesis that activation of the proinflammatory cytokine network is associated with fatigue symptoms during radiation therapy for breast and prostate cancer. Individuals with early-stage breast (n = 28) and prostate cancer (n = 20) completed questionnaires and provided blood samples for determination of serum levels of interleukin 1beta (IL-1beta) and IL-6 at assessments conducted before, during, and after a course of radiation therapy. Serum markers of proinflammatory cytokine activity, including IL-1 receptor antagonist and C-reactive protein, were examined in a subset of participants. Random coefficient models were used to evaluate the association between changes in cytokine levels and fatigue. As expected, there was a significant increase in fatigue during radiation treatment. Changes in serum levels of inflammatory markers C-reactive protein and IL-1 receptor antagonist were positively associated with increases in fatigue symptoms (Ps < 0.05), although serum levels of IL-1beta and IL-6 were not associated with fatigue. These effects remained significant (Ps < 0.05) in analyses controlling for potential biobehavioral confounding factors, including age, body mass index, hormone therapy, depression, and sleep disturbance. Results suggest that activation of the proinflammatory cytokine network and associated increases in downstream biomarkers of proinflammatory cytokine activity are associated with fatigue during radiation therapy for breast and prostate cancer.

Treatment Parameters and Outcome in 680 Treatments of Internal Radiation With Resin {sup 90}Y-Microspheres for Unresectable Hepatic Tumors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kennedy, Andrew S.; McNeillie, Patrick M.S.; Dezarn, William A.

Purpose: Radioembolization (RE) using {sup 90}Y-microspheres is an effective and safe treatment for patients with unresectable liver malignancies. Radiation-induced liver disease (RILD) is rare after RE; however, greater understanding of radiation-related factors leading to serious liver toxicity is needed. Methods and Materials: Retrospective review of radiation parameters was performed. All data pertaining to demographics, tumor, radiation, and outcomes were analyzed for significance and dependencies to develop a predictive model for RILD. Toxicity was scored using the National Cancer Institute Common Toxicity Criteria Adverse Events Version 3.0 scale. Results: A total of 515 patients (287 men; 228 women) from 14 USmore » and 2 EU centers underwent 680 separate RE treatments with resin {sup 90}Y-microspheres in 2003-2006. Multifactorial analyses identified factors related to toxicity, including activity (GBq) Selective Internal Radiation Therapy delivered (p < 0.0001), prescribed (GBq) activity (p < 0.0001), percentage of empiric activity (GBq) delivered (p < 0.0001), number of prior liver treatments (p < 0.0008), and medical center (p < 0.0001). The RILD was diagnosed in 28 of 680 treatments (4%), with 21 of 28 cases (75%) from one center, which used the empiric method. Conclusions: There was an association between the empiric method, percentage of calculated activity delivered to the patient, and the most severe toxicity, RILD. A predictive model for RILD is not yet possible given the large variance in these data.« less

Role of Ferulic Acid in the Amelioration of Ionizing Radiation Induced Inflammation: A Murine Model

PubMed Central

Das, Ujjal; Manna, Krishnendu; Sinha, Mahuya; Datta, Sanjukta; Das, Dipesh Kr; Chakraborty, Anindita; Ghosh, Mahua; Saha, Krishna Das; Dey, Sanjit

2014-01-01

Ionizing radiation is responsible for oxidative stress by generating reactive oxygen species (ROS), which alters the cellular redox potential. This change activates several redox sensitive enzymes which are crucial in activating signaling pathways at molecular level and can lead to oxidative stress induced inflammation. Therefore, the present study was intended to assess the anti-inflammatory role of ferulic acid (FA), a plant flavonoid, against radiation-induced oxidative stress with a novel mechanistic viewpoint. FA was administered (50 mg/kg body wt) to Swiss albino mice for five consecutive days prior to exposing them to a single dose of 10 Gy 60Co γ-irradiation. The dose of FA was optimized from the survival experiment and 50 mg/kg body wt dose showed optimum effect. FA significantly ameliorated the radiation induced inflammatory response such as phosphorylation of IKKα/β and IκBα and consequent nuclear translocation of nuclear factor kappa B (NF-κB). FA also prevented the increase of cycloxygenase-2 (Cox-2) protein, inducible nitric oxide synthase-2 (iNOS-2) gene expression, lipid peroxidation in liver and the increase of tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) in serum. It was observed that exposure to radiation results in decreased activity of superoxide dismutase (SOD), catalase (CAT) and the pool of reduced glutathione (GSH) content. However, FA treatment prior to irradiation increased the activities of the same endogenous antioxidants. Thus, pretreatment with FA offers protection against gamma radiation induced inflammation. PMID:24854039

Solid state radiative heat pump

DOEpatents

Berdahl, P.H.

1984-09-28

A solid state radiative heat pump operable at room temperature (300 K) utilizes a semiconductor having a gap energy in the range of 0.03-0.25 eV and operated reversibly to produce an excess or deficit of change carriers as compared equilibrium. In one form of the invention an infrared semiconductor photodiode is used, with forward or reverse bias, to emit an excess or deficit of infrared radiation. In another form of the invention, a homogenous semiconductor is subjected to orthogonal magnetic and electric fields to emit an excess or deficit of infrared radiation. Three methods of enhancing transmission of radiation the active surface of the semiconductor are disclosed. In one method, an anti-refection layer is coated into the active surface of the semiconductor, the anti-reflection layer having an index of refraction equal to the square root of that of the semiconductor. In the second method, a passive layer is speaced trom the active surface of the semiconductor by a submicron vacuum gap, the passive layer having an index of refractive equal to that of the semiconductor. In the third method, a coupler with a paraboloid reflecting surface surface is in contact with the active surface of the semiconductor, the coupler having an index of refraction about the same as that of the semiconductor.

Er:YAG and CTH:YAG laser radiation: contact versus non-contact enamel ablation and sonic-activated bulk composite placement

NASA Astrophysics Data System (ADS)

Buckova, M.; Kasparova, M.; Dostalova, T.; Jelinkova, H.; Sulc, J.; Nemec, M.; Fibrich, M.; Bradna, P.; Miyagi, M.

2013-05-01

Laser radiation can be used for effective caries removal and cavity preparation without significant thermal effects, collateral damage of tooth structure, or patient discomfort. The aim of this study was to compare the quality of tissue after contact or non-contact Er:YAG and CTH:YAG laser radiation ablation. The second goal was to increase the sealing ability of hard dental tissues using sonic-activated bulk filling material with change in viscosity during processing. The artificial caries was prepared in intact teeth to simulate a demineralized surface and then the Er:YAG or CTH:YAG laser radiation was applied. The enamel artificial caries was gently removed by the laser radiation and sonic-activated composite fillings were inserted. A stereomicroscope and then a scanning electron microscope were used to evaluate the enamel surface. Er:YAG contact mode ablation in enamel was quick and precise; the cavity was smooth with a keyhole shaped prism and rod relief arrangement without a smear layer. The sonic-activated filling material was consistently regularly distributed; no cracks or microleakage in the enamel were observed. CTH:YAG irradiation was able to clean but not ablate the enamel surface; in contact and also in non-contact mode there was evidence of melting and fusing of the enamel.

Radiation and inhibition of angiogenesis by canstatin synergize to induce HIF-1α–mediated tumor apoptotic switch

PubMed Central

Magnon, Claire; Opolon, Paule; Ricard, Marcel; Connault, Elisabeth; Ardouin, Patrice; Galaup, Ariane; Métivier, Didier; Bidart, Jean-Michel; Germain, Stéphane; Perricaudet, Michel; Schlumberger, Martin

2007-01-01

Tumor radioresponsiveness depends on endothelial cell death, which leads in turn to tumor hypoxia. Radiation-induced hypoxia was recently shown to trigger tumor radioresistance by activating angiogenesis through hypoxia-inducible factor 1–regulated (HIF-1–regulated) cytokines. We show here that combining targeted radioiodide therapy with angiogenic inhibitors, such as canstatin, enhances direct tumor cell apoptosis, thereby overcoming radio-induced HIF-1–dependent tumor survival pathways in vitro and in vivo. We found that following dual therapy, HIF-1α increases the activity of the canstatin-induced αvβ5 signaling tumor apoptotic pathway and concomitantly abrogates mitotic checkpoint and tetraploidy triggered by radiation. Apoptosis in conjunction with mitotic catastrophe leads to lethal tumor damage. We discovered that HIF-1 displays a radiosensitizing activity that is highly dependent on treatment modalities by regulating key apoptotic molecular pathways. Our findings therefore support a crucial role for angiogenesis inhibitors in shifting the fate of radiation-induced HIF-1α activity from hypoxia-induced tumor radioresistance to hypoxia-induced tumor apoptosis. This study provides a basis for developing new biology-based clinically relevant strategies to improve the efficacy of radiation oncology, using HIF-1 as an ally for cancer therapy. PMID:17557121

Covariability in the Monthly Mean Convective and Radiative Diurnal Cycles in the Amazon

NASA Technical Reports Server (NTRS)

Dodson, Jason B.; Taylor, Patrick C.

2015-01-01

The diurnal cycle of convective clouds greatly influences the radiative energy balance in convectively active regions of Earth, through both direct presence, and the production of anvil and stratiform clouds. Previous studies show that the frequency and properties of convective clouds can vary on monthly timescales as a result of variability in the monthly mean atmospheric state. Furthermore, the radiative budget in convectively active regions also varies by up to 7 Wm-2 in convectively active regions. These facts suggest that convective clouds connect atmospheric state variability and radiation variability beyond clear sky effects alone. Previous research has identified monthly covariability between the diurnal cycle of CERES-observed top-of-atmosphere radiative fluxes and multiple atmospheric state variables from reanalysis over the Amazon region. ASVs that enhance (reduce) deep convection, such as CAPE (LTS), tend to shift the daily OLR and cloud albedo maxima earlier (later) in the day by 2-3 hr. We first test the analysis method using multiple reanalysis products for both the dry and wet seasons to further investigate the robustness of the preliminary results. We then use CloudSat data as an independent cloud observing system to further evaluate the relationships of cloud properties to variability in radiation and atmospheric states. While CERES can decompose OLR variability into clear sky and cloud effects, it cannot determine what variability in cloud properties lead to variability in the radiative cloud effects. Cloud frequency, cloud top height, and cloud microphysics all contribute to the cloud radiative effect, all of which are observable by CloudSat. In addition, CloudSat can also observe the presence and variability of deep convective cores responsible for the production of anvil clouds. We use these capabilities to determine the covariability of convective cloud properties and the radiative diurnal cycle.

Interspecific Variability in Sensitivity to UV Radiation and Subsequent Recovery in Selected Isolates of Marine Bacteria†

PubMed Central

Arrieta, Jesús María; Weinbauer, Markus G.; Herndl, Gerhard J.

2000-01-01

The interspecific variability in the sensitivity of marine bacterial isolates to UV-B (295- to 320-nm) radiation and their ability to recover from previous UV-B stress were examined. Isolates originating from different microenvironments of the northern Adriatic Sea were transferred to aged seawater and exposed to artificial UV-B radiation for 4 h and subsequently to different radiation regimens excluding UV-B to determine the recovery from UV-B stress. Bacterial activity was assessed by thymidine and leucine incorporation measurements prior to and immediately after the exposure to UV-B and after the subsequent exposure to the different radiation regimens. Large interspecific differences among the 11 bacterial isolates were found in the sensitivity to UV-B, ranging from 21 to 92% inhibition of leucine incorporation compared to the bacterial activity measured in dark controls and from 14 to 84% for thymidine incorporation. Interspecific differences in the recovery from the UV stress were also large. An inverse relation was detectable between the ability to recover under dark conditions and the recovery under photosynthetic active radiation (400 to 700 nm). The observed large interspecific differences in the sensitivity to UV-B radiation and even more so in the subsequent recovery from UV-B stress are not related to the prevailing radiation conditions of the microhabitats from which the bacterial isolates originate. Based on our investigations on the 11 marine isolates, we conclude that there are large interspecific differences in the sensitivity to UV-B radiation and even larger differences in the mechanisms of recovery from previous UV stress. This might lead to UV-mediated shifts in the bacterioplankton community composition in marine surface waters. PMID:10742228

Self-indicating radiation alert dosemeter (SIRAD).

PubMed

Riel, Gordon K; Winters, Patrick; Patel, Gordhan; Patel, Paresh

2006-01-01

In an event of a nuclear or dirty bomb explosion and a radiological accident, there is a need for self-indicating instant radiation dosemeter for monitoring radiation exposure. The self-indicating instant radiation alert dosemeter (SIRAD) is a credit card size radiation dosemeter for monitoring ionising radiation from a few hundredths of a Gray to a few Gray. It is always active and is ready to use. It needs no battery. The dosemeter develops colour instantly upon exposure, and the colour intensifies with dose. It has a colour chart so that the dose on the active element may be read by matching its colour with the chart that is printed next to it on the card. However, in this work, the dose is measured by the optical density of the element. The dosemeter cannot be reset. The response changes by <1% per degrees C from -20 to +60 degrees C. The shelf-life is >3 y at room temperature. It contains no hazardous materials. The dosemeter would meet the requirements of instantly monitoring high dose in an event of a nuclear or dirty bomb explosion or a radiation accident.

Effect of infrared and microwave radiations on properties of Indian Horse Chestnut starch.

PubMed

Shah, Umar; Gani, Adil; Ashwar, Bilal Ahmad; Shah, Asima; Wani, Idrees Ahmed; Masoodi, Farooq Ahmad

2016-03-01

Starch extracted from Indian Horse Chestnut (IHCN) was subjected to infrared and microwave radiations for different time intervals (15 s, 30 s, & 45 s) at constant dose. The structural change of MW and IR radiated IHCN starches were determined by Fourier transform-infra red spectroscopy. The increased peak intensity at 3240 cm(-1) of treated starch represents more exposure of hydroxyl groups due to radiation. Granule morphology of native starch showed round and elliptical granules with smooth surfaces. However radiation treatment resulted in the development of surface cracks. Effect of radiation on physicochemical properties of starch revealed increase in water absorption capacity and light transmittance and decrease in apparent amylose content, pH, and syneresis. The peak, trough, final, and setback viscosities were significantly reduced with increase in treatment time. Radiated starches displayed significantly lower values of To,Tp, and ΔHgel than native starch. Further antioxidant activities were evaluated by DPPH and FRAP assays. Results showed significant improvement in antioxidant activity of starch by both MW and IR treatments. Copyright © 2015 Elsevier B.V. All rights reserved.

Graphdiyne Nanoparticles with High Free Radical Scavenging Activity for Radiation Protection.

PubMed

Xie, Jiani; Wang, Ning; Dong, Xinghua; Wang, Chengyan; Du, Zhen; Mei, Linqiang; Yong, Yuan; Huang, Changshui; Li, Yuliang; Gu, Zhanjun; Zhao, Yuliang

2018-03-06

Numerous carbon networks materials comprised of benzene moieties, such as graphene and fullerene, have held great fascination for radioprotection because of their acknowledged good biocompatibility and strong free radical scavenging activity derived from their delocalized π-conjugated structure. Recently, graphdiyne, a new emerging carbon network material consisting of a unique chemical structure of benzene and acetylenic moieties, has gradually attracted attention in many research fields. Encouraged by its unique structure with strong conjugated π-system and highly reactive diacetylenic linkages, graphdiyne might have free radical activity and can thus be used as a radioprotector, which has not been investigated so far. Herein, for the first time, we synthesized bovine serum albumin (BSA)-modified graphdiyne nanoparticles (graphdiyne-BSA NPs) to evaluate their free radical scavenging ability and investigate their application for radioprotection both in cell and animal models. In vitro studies indicated that the graphdiyne-BSA NPs could effectively eliminate the free-radicals, decrease radiation-induced DNA damage in cells, and improve the viability of cells under ionizing radiation. In vivo experiments showed that the graphdiyne-BSA NPs could protect the bone marrow DNA of mice from radiation-induced damage and make the superoxide dismutase (SOD) and malondialdehyde (MDA) (two kinds of vital indicators of radiation-induced injury) recover back to normal levels. Furthermore, the good biocompatibility and negligible systemically toxicity responses of the graphdiyne-BSA NPs to mice were verified. All these results manifest the good biosafety and radioprotection activity of graphdiyne-BSA NPs to normal tissues. Therefore, our studies not only provide a new radiation protection platform based on graphdiyne for protecting normal tissues from radiation-caused injury but also provide a promising direction for the application of graphdiyne in the biomedicine field.

Effects of UV-B radiation on growth, photosynthesis, UV-B-absorbing compounds and NADP-malic enzyme in bean (Phaseolus vulgaris L.) grown under different nitrogen conditions.

PubMed

Pinto, M E; Casati, P; Hsu, T P; Ku, M S; Edwards, G E

1999-02-01

The effects of UV-B radiation on growth, photosynthesis, UV-B-absorbing compounds and NADP-malic enzyme have been examined in different cultivars of Phaseolous vulgaris L. grown under 1 and 12 mM nitrogen. Low nitrogen nutrition reduces chlorophyll and soluble protein contents in the leaves and thus the photosynthesis rate and dry-matter accumulation. Chlorophyll, soluble protein and Rubisco contents and photosynthesis rate are not significantly altered by ambient levels of UV-B radiation (17 microW m-2, 290-320 nm, 4 h/day for one week). Comparative studies show that under high nitrogen, UV-B radiation slightly enhances leaf expansion and dry-matter accumulation in cultivar Pinto, but inhibits these parameters in Vilmorin. These results suggest that the UV-B effect on growth is mediated through leaf expansion, which is particularly sensitive to UV-B, and that Pinto is more tolerant than Vilmorin. The effect of UV-B radiation on UV-B-absorbing compounds and on NADP-malic enzyme (NADP-ME) activity is also examined. Both UV-B radiation and low-nitrogen nutrition enhance the content of UV-B-absorbing compounds, and among the three cultivars used, Pinto exhibits the highest increases and Arroz the lowest. The same trend is observed for the specific activity and content of NADP-ME. On a leaf-area basis, the amount of UV-B-absorbing compounds is highly correlated with the enzyme activity (r2 = 0.83), suggesting that NADP-ME plays a key role in biosynthesis of these compounds. Furthermore, the higher sensitivity of Vilmorin than Pinto to UV-B radiation appears to be related to the activity of NADP-ME and the capacity of the plants to accumulate UV-B-absorbing compounds.

[The opportunity to use combined stem cells transplantation for haemopoesis activation in the old and mature laboratory animals under the conditions of ionizing radiation].

PubMed

Grebnev, D U

2014-01-01

The objective of this work was to study the influence of combined transplantation of stem cells (multypotent mesenchimal stromal and hem poetic stem cells) on the haemopoesis of old and mature laboratory animals under the condition of ionizing radiation. The experiments were conducted on 48 white male mice with the body weight of 30 g, age of 3-4 months, and 48 male mice of 3 years of age and body mass of 50 g. The experiments for obtaining the MMSC and HSC cultures were conducted on 16 laboratory animals: female mice of 3-4 months of age and body mass of 30 g., 18 days gestation period. The control group was formed by the animals not under the ionizing radiation. The experimental group animals got the dose of 4 Gr. These animals also got MMSC and HSC mixture intravenously in the doses of 6 mln. c/kg. and 330 thousand cell/kg prospectively. The control group animals got the 0.9% NaCl - 0.2 ml. intravenously. The infusions were made 1 hour after radiation once. As the result of the experiment it was shown that under physiological conditions combined transplantation brings the erithropoesis activation, under the ionizing radiation conditions it brings the erythroid and granulocytopoesis activation. More over the combined MMSC and HSC transplantation gives cytoprotective action on the myeloid tissue due to decrease of cyto genically changed cells in the mature animals under the condition of ionizing radiation, but in the old animals this effect can be seen even under physiological condition. Conclusions: Combined transplantation of MMSC and GSC can be used in the mature and old laboratory animals under the conditions of ionising radiation for the haemopoesis activation.

Anti-radiation damage effect of polyethylenimine as a toll-like receptor 5 targeted agonist

PubMed Central

Hu, Zhiqiang; Xing, Yaling; Qian, Yuanyu; Chen, Xiaojuan; Tu, Jian; Ren, Lening; Wang, Kai; Chen, Zhongbin

2013-01-01

A number of agents are now available for use in protecting against ionizing radiation. These radiation-protective agents, however, have many adverse effects. Efforts have been made to develop new radiation-protective agents for medical application. Here, we investigated whether a compound, polyethylenimine (PEI), which activates Toll-like receptor 5 (TLR5)-mediated NF-kB signaling pathways, could have an anti-radiation effect on a mouse model. First, a cell-based screening model for an agonist of TLR5-mediated NF-kB pathway was established and then validated by activation of TLR5-mediated NF-kB luciferase reporter activity with a known TLR5 agonist, flagellin. We found that PEI induced dose-dependent activation of the TLR5-mediated NF-kB pathway, indicating that PEI is indeed a TLR5 agonist. Furthermore, the anti-radiation effect of polyethylenimine was assessed using a γ-ray total body irradiation (TBI) mouse model. Compared with the irradiation control, both survival time and survival rate were significantly improved in mice that received either a low dose of polyethylenimine (P= 0.019) or a high dose of polyethylenimine (P< 0.001). We also observed a positive correlation between animal body weight and survival time in mice that received a low dose of polyethylenimine, a high dose of polyethylenimine and amifostine, over a period of 30 days, r= 0.42 (P< 0.02), 0.72 (P< 0.0001) and 0.95 (P< 0.0001), respectively, while a negative correlation between animal body weight and survival time was observed in the irradiation control (r= –0.89; P< 0.0001). These results indicate that polyethylenimine is a new TLR5 agonist with potential application in offering protection for patients receiving radiotherapy or in radiation-related accidents. PMID:23104900

Anti-radiation damage effect of polyethylenimine as a toll-like receptor 5 targeted agonist.

PubMed

Hu, Zhiqiang; Xing, Yaling; Qian, Yuanyu; Chen, Xiaojuan; Tu, Jian; Ren, Lening; Wang, Kai; Chen, Zhongbin

2013-03-01

A number of agents are now available for use in protecting against ionizing radiation. These radiation-protective agents, however, have many adverse effects. Efforts have been made to develop new radiation-protective agents for medical application. Here, we investigated whether a compound, polyethylenimine (PEI), which activates Toll-like receptor 5 (TLR5)-mediated NF-kB signaling pathways, could have an anti-radiation effect on a mouse model. First, a cell-based screening model for an agonist of TLR5-mediated NF-kB pathway was established and then validated by activation of TLR5-mediated NF-kB luciferase reporter activity with a known TLR5 agonist, flagellin. We found that PEI induced dose-dependent activation of the TLR5-mediated NF-kB pathway, indicating that PEI is indeed a TLR5 agonist. Furthermore, the anti-radiation effect of polyethylenimine was assessed using a γ-ray total body irradiation (TBI) mouse model. Compared with the irradiation control, both survival time and survival rate were significantly improved in mice that received either a low dose of polyethylenimine (P= 0.019) or a high dose of polyethylenimine (P< 0.001). We also observed a positive correlation between animal body weight and survival time in mice that received a low dose of polyethylenimine, a high dose of polyethylenimine and amifostine, over a period of 30 days, r= 0.42 (P< 0.02), 0.72 (P< 0.0001) and 0.95 (P< 0.0001), respectively, while a negative correlation between animal body weight and survival time was observed in the irradiation control (r= -0.89; P< 0.0001). These results indicate that polyethylenimine is a new TLR5 agonist with potential application in offering protection for patients receiving radiotherapy or in radiation-related accidents.

Continuous Activity Monitoring During Concurrent Chemoradiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ohri, Nitin, E-mail: ohri.nitin@gmail.com; Kabarriti, Rafi; Bodner, William R.

Purpose: To perform a prospective trial testing the feasibility and utility of acquiring activity data as a measure of health status during concurrent chemoradiotherapy. Methods and Materials: Ambulatory patients who were planned for treatment with concurrent chemoradiotherapy with curative intent for cancers of the head and neck, lung, or gastrointestinal tract were provided with activity monitors before treatment initiation. Patients were asked to wear the devices continuously throughout the radiation therapy course. Step count data were downloaded weekly during radiation therapy and 2 and 4 weeks after radiation therapy completion. The primary objective was to demonstrate feasibility, defined as collection ofmore » step counts for 80% of the days during study subjects' radiation therapy courses. Secondary objectives included establishing step count as a dynamic predictor of unplanned hospitalization risk. Results: Thirty-eight enrolled patients were treated with concurrent chemoradiotherapy. Primary diagnoses included head and neck cancer (n=11), lung cancer (n=13), and a variety of gastrointestinal cancers (n=14). Step data were collected for 1524 of 1613 days (94%) during patients' radiation therapy courses. Fourteen patients were hospitalized during radiation therapy or within 4 weeks of radiation therapy completion. Cox regression modeling demonstrated a significant association between recent step counts (3-day average) and hospitalization risk, with a 38% reduction in the risk of hospitalization for every 1000 steps taken each day (hazard ratio 0.62, 95% confidence interval 0.46-0.83, P=.002). Inferior quality of life scores and impaired performance status were not associated with increased hospitalization risk. Conclusion: Continuous activity monitoring during concurrent chemoradiotherapy is feasible and well-tolerated. Step counts may serve as powerful, objective, and dynamic indicators of hospitalization risk.« less

Ablative Hypofractionated Radiation Therapy Enhances Non-Small Cell Lung Cancer Cell Killing via Preferential Stimulation of Necroptosis In Vitro and In Vivo.

PubMed

Wang, Huan-Huan; Wu, Zhi-Qiang; Qian, Dong; Zaorsky, Nicholas G; Qiu, Ming-Han; Cheng, Jing-Jing; Jiang, Chao; Wang, Juan; Zeng, Xian-Liang; Liu, Chun-Lei; Tian, Li-Jun; Ying, Guo-Guang; Meng, Mao-Bin; Hao, Xi-Shan; Yuan, Zhi-Yong

2018-05-01

To investigate how necroptosis (ie, programmed necrosis) is involved in killing of non-small cell lung cancer (NSCLC) after ablative hypofractionated radiation therapy (HFRT). Deoxyribonucleic acid damage, DNA repair, and the death form of NSCLC cells were assessed after radiation therapy. The overexpression and silencing of receptor-interacting protein kinases 3 (RIP3, a key protein involved activation of necroptosis)-stable NSCLC cell lines were successfully constructed. The form of cell death, the number and area of colonies, and the regulatory proteins of necroptosis were characterized after radiation therapy in vitro. Finally, NSCLC xenografts and patient specimens were used to examine involvement of necroptosis after ablative HFRT in vivo. Radiation therapy induced expected DNA damage and repair of NSCLC cell lines, but ablative HFRT at ≥10 Gy per fraction preferentially stimulated necroptosis in NSCLC cells and xenografts with high RIP3 expression, as characterized by induction and activation of RIP3 and mixed-lineage kinase domain-like protein and release of immune-activating chemokine high-mobility group box 1. In contrast, RNA interference of RIP3 attenuated ablative HFRT-induced necroptosis and activation of its regulatory proteins. Among central early-stage NSCLC patients receiving stereotactic body radiation therapy, high expression of RIP3 was associated with improved local control and progression-free survival (all P < .05). Ablative HFRT at ≥10 Gy per fraction enhances killing of NSCLC with high RIP3 expression via preferential stimulation of necroptosis. RIP3 may serve as a useful biomarker to predict favorable response to stereotactic body radiation therapy. Copyright © 2018 Elsevier Inc. All rights reserved.

Caspase 3 promotes genetic instability and carcinogenesis

PubMed Central

Liu, Xinjian; He, Yujun; Li, Fang; Huang, Qian; Kato, Takamitsu A.; Hall, Russell P; Li, Chuan-Yuan

2015-01-01

Summary Apoptosis is typically considered an anti-oncogenic process since caspase activation can promote the elimination of genetically unstable or damaged cells. We report that a central effector of apoptosis, caspase 3, facilitates, rather than suppresses, chemical and radiation-induced genetic instability and carcinogenesis. We found that a significant fraction of mammalian cells treated with ionizing radiation can survive, despite caspase 3 activation. Moreover, this sublethal activation of caspase 3 promoted persistent DNA damage and oncogenic transformation. In addition, chemically-induced skin carcinogenesis was significantly reduced in mice genetically deficient in caspase 3. Furthermore, attenuation of Endo G activity significantly reduced radiation-induced DNA damage and oncogenic transformation, identifying Endo G as a downstream effector of caspase 3 in this pathway. Our findings suggest that rather than acting as a broad inhibitor of carcinogenesis, caspase 3 activation may contribute to genome instability and play a pivotal role in tumor formation following damage. PMID:25866249

Effects of gamma radiation on cork wastewater: Antioxidant activity and toxicity.

PubMed

Madureira, Joana; Pimenta, Andreia I; Popescu, Larisa; Besleaga, Alexandra; Dias, Maria Inês; Santos, Pedro M P; Melo, Rita; Ferreira, Isabel C F R; Cabo Verde, Sandra; Margaça, Fernanda M A

2017-02-01

A comprehensive assessment of the toxicity and antioxidant activity of cork boiling wastewater and the effects of gamma radiation on these parameters was performed. Antioxidant activity was evaluated using different methodologies as DPPH radical scavenging activity, reducing power and inhibition of β-carotene bleaching. The results have shown that gamma radiation can induce an increase on the antioxidant activity of cork boiling wastewater. Toxicity tests were performed to access the potential added value of the irradiated wastewaters and/or minimization of the impact for discharge in the environment. Two different methods for toxicity evaluation were followed, bacterial growth inhibition test and cytotoxicity assay, in order to predict the behavior of different cells (prokaryotic and eukaryotic) in the presence of cork wastewater. Non-treated cork boiling wastewater seemed to be non-toxic for prokaryotic cells (Pseudomonas fluorescens and Bacillus subtilis) but toxic for eukaryotic cells (A549 human cells and RAW264.7 mouse cells). The gamma radiation treatment at doses of 100 kGy appeared to increase the toxicity of cork compounds for all tested cells, which could be related to a toxic effect of radiolytic products of cork compounds in the wastewaters. Copyright © 2016 Elsevier Ltd. All rights reserved.

The DOSIS -Experiment onboard the Columbus Laboratory of the International Space Station -First Mission Results from the Active DOSTEL Instruments

NASA Astrophysics Data System (ADS)

Burmeister, Soenke; Berger, Thomas; Beaujean, Rudolf; Boehme, Matthias; Haumann, Lutz; Kortmann, Onno; Labrenz, Johannes; Reitz, Guenther

Besides the effects of the microgravity environment, and the psychological and psychosocial problems encountered in confined spaces, radiation is the main health detriment for long dura-tion human space missions. The radiation environment encountered in space differs in nature from that on earth, consisting mostly of high energetic ions from protons up to iron, resulting in radiation levels far exceeding the ones encountered on earth for occupational radiation workers. Accurate knowledge of the physical characteristics of the space radiation field in dependence on the solar activity, the orbital parameters and the different shielding configurations of the International Space Station ISS is therefore needed. For the investigation of the spatial and temporal distribution of the radiation field inside the European COLUMBUS module the DLR experiment DOSIS (Dose Distribution Inside the ISS) was launched on July 15th 2009 with STS-127 to the ISS. The experimental package was transferred from the Space Shuttle into COLUMBUS on July 18th. It consists in a first part of a combination of passive detector packages (PDP) distributed at 11 locations inside the European Columbus Laboratory. The second part are two active radiation detectors (DOSTELs) with a DDPU (DOSIS Data and Power Unit) in a nomex pouch (DOSIS MAIN BOX) mounted at a fixed location beneath the European Physiology Module (EPM) inside COLUMBUS. After the successful installation the active part has been activated on the 18th July 2009. Each of the DOSTEL units consists of two 6.93 cm PIPS silicon detectors forming a telescope with an opening angle of 120. The two DOSTELs are mounted with their telescope axis perpendicular to each other to investigate anisotropies of the radiation field inside the COLUMBUS module especially during the passes through the South Atlantic Anomaly (SAA) and during Solar Particle Events (SPEs). The data from the DOSTEL units are transferred to ground via the EPM rack which is activated approximately every four weeks for this action. The first data downlink was performed on July 31st 2009. First Results for the DOSTEL measurements such as count rate profiles, dose rates and LET spectra will be presented in comparison to the data obtained by other experiments.

The Effects of Low Doses of Gamma-Radiation on Growth and Membrane Activity of Pseudomonas aeruginosa GRP3 and Escherichia coli M17.

PubMed

Soghomonyan, D; Margaryan, A; Trchounian, K; Ohanyan, K; Badalyan, H; Trchounian, A

2018-06-01

Microorganisms are part of the natural environments and reflect the effects of different physical factors of surrounding environment, such as gamma (γ) radiation. This work was devoted to the study of the influence of low doses of γ radiation with the intensity of 2.56 μW (m 2  s) -1 (absorbed doses were 3.8 mGy for the radiation of 15 min and 7.2 mGy-for 30 min) on Escherichia coli M-17 and Pseudomonas aeruginosa GRP3 wild type cells. The changes of bacterial, growth, survival, morphology, and membrane activity had been studied after γ irradiation. Verified microbiological (specific growth rate, lag phase duration, colony-forming units (CFU) number, and light microscopy digital image analysis), biochemical (ATPase activity of bacterial membrane vesicles), and biophysical (H + fluxes throughout cytoplasmic membrane of bacteria) methods were used for assessment of radiation implications on bacteria. It was shown that growth specific rate, lag phase duration and CFU number of these bacteria were lowered after irradiation, and average cell surface area was decreased too. Moreover ion fluxes of bacteria were changed: for P. aeruginosa they were decreased and for E. coli-increased. The N,N'-dicyclohexylcarbodiimide (DCCD) sensitive fluxes were also changed which were indicative for the membrane-associated F 0 F 1 -ATPase enzyme. ATPase activity of irradiated membrane vesicles was decreased for P. aeruginosa and stimulated for E. coli. Furthermore, DCCD sensitive ATPase activity was also changed. The results obtained suggest that these bacteria especially, P. aeruginosa are sensitive to γ radiation and might be used for developing new monitoring methods for estimating environmental changes after γ irradiation.

Gene expression profiling of breast cancer cell lines treated with proton and electron radiations.

PubMed

Bravatà, Valentina; Minafra, Luigi; Cammarata, Francesco Paolo; Pisciotta, Pietro; Lamia, Debora; Marchese, Valentina; Manti, Lorenzo; Cirrone, Giuseppe Ap; Gilardi, Maria Carla; Cuttone, Giacomo; Forte, Giusi Irma; Russo, Giorgio

2018-06-11

Technological advances in radiation therapy are evolving with the use of hadrons, such as protons, indicated for tumors where conventional radiotherapy does not give significant advantages or for tumors located in sensitive regions, which need the maximum of dose-saving of the surrounding healthy tissues. The genomic response to conventional and non conventional Linear Energy Transfer exposure is a poor investigated topic and became an issue of radiobiological interest. The aim of this work was to analyze and compare molecular responses in term of gene expression profiles, induced by electron and proton irradiation in breast cancer cell lines. We studied the gene expression profiling differences by cDNA microarray activated in response to electron and proton irradiation with different Linear Energy Transfer values, among three breast cell lines (the tumorigenic MCF7 and MDA-MB-231 and the non tumorigenic MCF10A), exposed to the same sub-lethal dose of 9 Gy. Gene expression profiling pathway analyses showed the activation of different signaling and molecular networks in a cell line and radiation type-dependent manner. MCF10A and MDA-MB-231 cell lines were found to induce factors and pathways involved in the immunological process control. Here we describe in a detailed way the gene expression profiling and pathways activated after electron and proton irradiation in breast cancer cells. Summarizing, although specific pathways are activated in a radiation type-dependent manner, each cell line activates overall similar molecular networks in response to both these two types of ionizing radiation. Advances in knowledge: In the era of personalized medicine and breast cancer target-directed intervention, we trust that this study could drive radiation therapy towards personalized treatments, evaluating possible combined treatments, based on the molecular characterization.

Active Control of Fan Noise-Feasibility Study. Volume 2: Canceling Noise Source-Design of an Acoustic Plate Radiator Using Piezoceramic Actuators

NASA Technical Reports Server (NTRS)

Pla, F. G.; Rajiyah, H.

1995-01-01

The feasibility of using acoustic plate radiators powered by piezoceramic thin sheets as canceling sources for active control of aircraft engine fan noise is demonstrated. Analytical and numerical models of actuated beams and plates are developed and validated. An optimization study is performed to identify the optimum combination of design parameters that maximizes the plate volume velocity for a given resonance frequency. Fifteen plates with various plate and actuator sizes, thicknesses, and bonding layers were fabricated and tested using results from the optimization study. A maximum equivalent piston displacement of 0.39 mm was achieved with the optimized plate samples tested with only one actuator powered, corresponding to a plate deflection at the center of over 1 millimeter. This is very close to the deflection required for a full size engine application and represents a 160-fold improvement over previous work. Experimental results further show that performance is limited by the critical stress of the piezoceramic actuator and bonding layer rather than by the maximum moment available from the actuator. Design enhancements are described in detail that will lead to a flight-worthy acoustic plate radiator by minimizing actuator tensile stresses and reducing nonlinear effects. Finally, several adaptive tuning methods designed to increase the bandwidth of acoustic plate radiators are analyzed including passive, active, and semi-active approaches. The back chamber pressurization and volume variation methods are investigated experimentally and shown to be simple and effective ways to obtain substantial control over the resonance frequency of a plate radiator. This study shows that piezoceramic-based plate radiators can be a viable acoustic source for active control of aircraft engine fan noise.

Radiative Energy Budget Studies Using Observations from the Earth Radiation Budget Experiment (ERBE)

NASA Technical Reports Server (NTRS)

Ackerman, Steven A.; Frey, R.; Shie, M.; Olson, R.; Collimore, C.; Friedman, M.

1997-01-01

Our research activities under this NASA grant have focused on two broad topics associated with the Earth Radiation Budget Experiment (ERBE): (1) the role of clouds and the surface in modifying the radiative balance; and (2) the spatial and temporal variability of the earth's radiation budget. Each of these broad topics is discussed separately in the text that follows. The major points of the thesis are summarized in section 3 of this report. Other dissertation focuses on deriving the radiation budget over the TOGA COARE region.

Cloud and Radiation Mission with Active and Passive Sensing from the Space Station

NASA Technical Reports Server (NTRS)

Spinhirne, James D.

1998-01-01

A cloud and aerosol radiative forcing and physical process study involving active laser and radar profiling with a combination of passive radiometric sounders and imagers would use the space station as an observation platform. The objectives are to observe the full three dimensional cloud and aerosol structure and the associated physical parameters leading to a complete measurement of radiation forcing processes. The instruments would include specialized radar and lidar for cloud and aerosol profiling, visible, infrared and microwave imaging radiometers with comprehensive channels for cloud and aerosol observation and specialized sounders. The low altitude,. available power and servicing capability of the space station are significant advantages for the active sensors and multiple passive instruments.

Effects of a tryptophan supplemented diet and U.V. radiation on the rat lens.

PubMed

Mathur, R L; Sahai, P

1990-01-01

Rats maintained on a tryptophan supplemented diet and exposed to U.V. radiation showed decreased concentration of ascorbic acid in serum. In the lens, a small increase in the urea-mercaptoethanol soluble fraction was observed suggesting some oxidation of P-SH groups. The decreased concentrations of lens glutathione and ascorbic acid were accompanied with increased concentration of malondialdehyde suggesting increased oxidative stress. The activities of glutathione peroxidase decreased by about 40%. Though the activity of glutathione reductase decreased by about 58%, addition of FAD in the enzyme assay system showed restoration of lost activity. Additive effect of raised serum tryptophan concentration and ultraviolet radiation in causing damage to the eye lens is suggested.

Approximating the Probability of Mortality Due to Protracted Radiation Exposures

DTIC Science & Technology

2016-06-01

syndrome of acute radiation sickness. In the MARCELL model, radiation exposure dynamically depletes the bone marrow cell population, the underpinning of...Protracted Radiation Exposures DTRA-TR-16-054 HDTRA1-14-D-0003; 0005 Prepared by: Applied Research Associates, Inc. 801 N. Quincy Street...Celsius (oC) degree Fahrenheit (oF) [T(oF) + 459.67]/1.8 kelvin (K) Radiation curie (Ci) [activity of radionuclides] 3.7 × 1010 per second (s–1

The DOSIS -Experiment onboard the Columbus Laboratory of the International Space Station -Overview and first mission results

NASA Astrophysics Data System (ADS)

Reitz, Guenther; Berger, Thomas; Kürner, Christine; Burmeister, Sünke; Hajek, Michael; Bilski, Pawel; Horwacik, Tomasz; Vanhavere, Filip; Spurny, Frantisek; Jadrnickova, Iva; Pálfalvi, József K.; O'Sullivan, Denis; Yasuda, Nakahiro; Uchihori, Yukio; Kitamura, Hisashi; Kodaira, Satoshi; Yukihara, Eduardo; Benton, Eric; Zapp, Neal; Gaza, Ramona; Zhou, Dazhuang; Semones, Edward; Roed, Yvonne; Boehme, Matthias; Haumann, Lutz

Besides the effects of the microgravity environment, and the psychological and psychosocial problems encountered in confined spaces, radiation is the main health detriment for long dura-tion human space missions. The radiation environment encountered in space differs in nature from that on earth, consisting mostly of high energetic ions from protons up to iron, resulting in radiation levels far exceeding the ones encountered on earth for occupational radiation workers. Accurate knowledge of the physical characteristics of the space radiation field in dependence on the solar activity, the orbital parameters and the different shielding configurations of the International Space Station ISS is therefore needed. The DOSIS (Dose Distribution inside the ISS) experiment, under the project and science lead of DLR, aims for the spatial and tempo-ral measurement of the radiation field parameters inside the European Columbus laboratory onboard the International Space Station. This goal is achieved by applying a combination of passive (Thermo-and Optical luminescence detectors and Nuclear track etch detectors) and active (silicon telescope) radiation detectors. The passive radiation detectors -so called pas-sive detector packages (PDP) are mounted at eleven positions within the Columbus laboratory -aiming for a spatial dose distribution measurement of the absorbed dose, the linear energy transfer spectra and the dose equivalent with an average exposure time of six months. Two active silicon telescopes -so called Dosimetry Telescopes (DOSTEL 1 and DOSTEL 2) together with a Data and Power Unit (DDPU) are mounted within the DOSIS Main Box at a fixed loca-tion beneath the European Physiology Module (EPM) rack. The DOSTEL 1 and DOSTEL 2 detectors are positioned at a 90 angle to each other for a precise measurement of the temporal and spatial variation of the radiation field, especially during crossing of the South Atlantic Anomaly (SAA). The DOSIS hardware was launched with the Space Shuttle Endeavour to the International Space Station on 15 July 2009 and installed by European Astronaut Frank de Winne on 18 July 2009. The first PDP set was downloaded after an exposure time of 124 days in November 2009 and a second PDP set was installed in November 2009. The active part of the instrument suit is working since July 2009. The presentation will give an overview about the DOSIS experiment as well as first results from the passive and active radiation detector measurements. The Austrian activities within this experiment were supported by the Austrian Space Appli-cations Programme (ASAP) of the Federal Ministry for Transport, Innovation and Technology under contract no. 819643. The Polish contribution to this work was supported by the Min-istry of Science and Higher Education, grant No. DWM/N118/ESA/2008. The Hungarian contribution was supported by the ESA PECS grant No. C98066.

Possible Mechanism of Infrared Radiation Reception: The Role of the Temperature Factor

NASA Astrophysics Data System (ADS)

Yachnev, I. L.; Penniyaynen, V. A.; Podzorova, S. A.; Rogachevskii, I. V.; Krylov, B. V.

2018-02-01

The role of the temperature factor in the mechanism of reception of the CO2 laser low-power infrared (IR) radiation (λ = 10.6 μm) by a sensory neuron membrane has been studied. Organotypic embryonic tissue culture has been used to measure and estimate the temperature of a sensory ganglia monolayer exposed to radiation at different energy densities. The effects of tissue exposure to low-power IR radiation have been investigated. It has been found that inhibition of tissue growth by radiation of low energy density (10-14-10-10 J/cm2) is replaced by tissue growth (10-7-10-4 J/cm2), and again followed by inhibition in the range of 0.1-6 J/cm2. A statistically significant specific reaction to nonthermal radiation has been detected at the radiation power density of 3 × 10-10 J/cm2, which is due to activation of the Na+,K+-ATPase transducer function. The mechanisms of interaction of IR radiation with embryonic nerve tissue have been considered. Low-power IR radiation with the wavelength of 10.6 μm has been demonstrated to specifically activate a novel signal transducer function of the sodium pump, which controls the reception of nonthermal IR radiation in the energy density range of 10-14 to 10-10 J/cm2.

Active Radiation Detectors for Use in Space Beyond Low Earth Orbit: Spatial and Energy Resolution Requirements and Methods for Heavy Ion Charge Classification

NASA Astrophysics Data System (ADS)

McBeth, Rafe A.

Space radiation exposure to astronauts will need to be carefully monitored on future missions beyond low earth orbit. NASA has proposed an updated radiation risk framework that takes into account a significant amount of radiobiological and heavy ion track structure information. These models require active radiation detection systems to measure the energy and ion charge Z. However, current radiation detection systems cannot meet these demands. The aim of this study was to investigate several topics that will help next generation detection systems meet the NASA objectives. Specifically, this work investigates the required spatial resolution to avoid coincident events in a detector, the effects of energy straggling and conversion of dose from silicon to water, and methods for ion identification (Z) using machine learning. The main results of this dissertation are as follows: 1. Spatial resolution on the order of 0.1 cm is required for active space radiation detectors to have high confidence in identifying individual particles, i.e., to eliminate coincident events. 2. Energy resolution of a detector system will be limited by energy straggling effects and the conversion of dose in silicon to dose in biological tissue (water). 3. Machine learning methods show strong promise for identification of ion charge (Z) with simple detector designs.

Changes of reduced glutathion, glutathion reductase, and glutathione peroxidase after radiation in guinea pigs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Erden, M.; Bor, N.M.

1984-04-01

In this series of experiments the protective action of reduced glutathion due to ionizing radiation has been studied. In the experimental group 18 guinea pigs were exposed to successive radiations of 150 rad 3 or 4 days apart. Total dose given amounted to 750 rad which is the LD50 for guinea pigs. Blood samples were taken 30 min after each exposure. The control series were sham radiated but otherwise treated identically. The cells of the removed blood samples were separated by centrifugation and were subjected to the reduced glutathion stability test. GSSGR, GPer, and LDH enzyme activities were also measuredmore » of which the latter served as a marked enzyme. It was found that LDH did not show any alteration after radiation. The reduced glutathion stability test showed a consistent but minor reduction (P greater than 0.05), in the experimental group. GSSGR enzyme activity on the other hand was reduced significantly (from 176.48 +/- 11.32 to 41.34 +/- 1.17 IU/ml of packed erythrocytes, P less than 0.001) in the same group. GPer activity showed a consistent but minor elevation during the early phase of the experimental group. It was later increased significantly beginning after 600 rad total radiation on the fourth session (P less than 0.050).« less

[Effect of UV-radiation on the level of ascorbic acid, SH-groups, and activity of glutathione reductase in the eye lens].

PubMed

Byshneva, L N; Senchuk, V V

2002-01-01

The effect of UV radiation in vitro on the level of ascorbate, SH-groups and glutathione reductase activity in the soluble fraction of bovine eye lens was studied. UV-Irradiation increased NADPH-oxidoreductase activity, the level of ascorbate oxidation and decreased the content of SH-groups and activity of glutathione reductase. Significant activation of the NADPH-oxidoreductase activity in the presence of ascorbate and Cu2+ was observed after UV-irradiation. It is suggested that ascorbate may play an important role in the UV-induced lens pathology.

Active noise control using noise source having adaptive resonant frequency tuning through variable ring loading

NASA Technical Reports Server (NTRS)

Rajiyah, Harindra (Inventor); Pla, Frederic G. (Inventor); Hedeen, Robert A. (Inventor); Renshaw, Anthony A. (Inventor)

1995-01-01

A noise source for an aircraft engine active noise cancellation system in which the resonant frequency of noise radiating structure is tuned to permit noise cancellation over a wide range of frequencies. The resonant frequency of the noise radiating structure is tuned by a plurality of drivers arranged to contact the noise radiating structure. Excitation of the drivers causes expansion or contraction of the drivers, thereby varying the edge loading applied to the noise radiating structure. The drivers are actuated by a controller which receives input of a feedback signal proportional to displacement of the noise radiating element and a signal corresponding to the blade passage frequency of the engine's fan. In response, the controller determines a control signal which is sent to the drivers, causing them to expand or contract. The noise radiating structure may be either the outer shroud of the engine or a ring mounted flush with an inner wall of the shroud or disposed in the interior of the shroud.

Structural-electrical coupling optimisation for radiating and scattering performances of active phased array antenna

NASA Astrophysics Data System (ADS)

Wang, Congsi; Wang, Yan; Wang, Zhihai; Wang, Meng; Yuan, Shuai; Wang, Weifeng

2018-04-01

It is well known that calculating and reducing of radar cross section (RCS) of the active phased array antenna (APAA) are both difficult and complicated. It remains unresolved to balance the performance of the radiating and scattering when the RCS is reduced. Therefore, this paper develops a structure and scattering array factor coupling model of APAA based on the phase errors of radiated elements generated by structural distortion and installation error of the array. To obtain the optimal radiating and scattering performance, an integrated optimisation model is built to optimise the installation height of all the radiated elements in normal direction of the array, in which the particle swarm optimisation method is adopted and the gain loss and scattering array factor are selected as the fitness function. The simulation indicates that the proposed coupling model and integrated optimisation method can effectively decrease the RCS and that the necessary radiating performance can be simultaneously guaranteed, which demonstrate an important application value in engineering design and structural evaluation of APAA.

SU-F-T-154: An Evaluation and Quantification of Secondary Neutron Radiation Dose Due to Double Scatter and Pencil Beam Scanning Proton Therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Glick, A; Diffenderfer, E

2016-06-15

Proton radiation therapy can deliver high radiation doses to tumors while sparing normal tissue. However, protons yield secondary neutron and gamma radiation that is difficult to detect, small in comparison to the prescribed dose, and not accounted for in most treatment planning systems. The risk for secondary malignancies after proton therapy may be dependent on the quality of this dose. Consequently, there is interest in characterizing the secondary radiation. Previously, we used the dual ionization chamber method to measure the separate absorbed dose from gamma-rays and neutrons secondary to the proton beam1, relying on characterization of ionization chamber response inmore » the unknown neutron spectrum from Monte Carlo simulation. We developed a procedure to use Shieldwerx activation foils, with neutron activation energies ranging from 0.025 eV to 13.5 MeV, to measure the neutron energy spectrum from double scattering (DS) and pencil beam scanning (PBS) protons outside of the treatment volume in a water tank. The activated foils are transferred to a NaI well chamber for gamma-ray spectroscopy and activity measurement. Since PBS treats in layers, the switching time between layers is used to correct for the decay of the activated foils and the relative dose per layer is assumed to be proportional to the neutron fluence per layer. MATLAB code was developed to incorporate the layer delivery and switching time into a calculation of foil activity, which is then used to determine the neutron energy fluence from tabulated foil activation energy thresholds.1. Diffenderfer et. al., Med. Phys., 38(11) 2011.« less

Saussurea tridactyla Sch. Bip.-derived polysaccharides and flavones reduce oxidative damage in ultraviolet B-irradiated HaCaT cells via a p38MAPK-independent mechanism

PubMed Central

Guo, Yan; Sun, Juan; Ye, Juan; Ma, Wenyu; Yan, Hualing; Wang, Gang

2016-01-01

Objective To investigate whether Saussurea tridactyla Sch. Bip.-derived polysaccharides and flavones exert apoptosis-inhibiting effects in ultraviolet B (UVB)-irradiated HaCaT cells. Methods We divided HaCaT cells into low radiation UVB and high radiation UVB groups. Low radiation UVB and high radiation UVB groups were further divided into a control group, UVB radiation group (UVB group), S. tridactyla Sch. Bip.-derived polysaccharides and flavones low-dose group, and S. tridactyla Sch. Bip.-derived polysaccharides and flavones high-dose group. Cell viability and morphology were assayed by MTT and trypan blue staining. Superoxide dismutase activity, glutathione content, malondialdehyde content, and catalase activity test kits were used to detect superoxide dismutase activity, glutathione content, malondialdehyde content, and catalase activity, respectively. Cell apoptosis, intracellular Ca2+ levels, and mitochondrial membrane potential (Δψ) were detected by flow cytometry. Protein levels were analyzed by Western blotting and immunofluorescence. Results S. tridactyla Sch. Bip.-derived polysaccharides and flavones were found to increase the absorbance of MTT, decrease cell death, alleviate the degree of cell edema, restore the cell morphology, reduce cell death fragments and chip phenomenon, increase superoxide dismutase activity, glutathione content, and catalase activity while decreasing the content of malondialdehyde, lowering the population of apoptotic cells, reducing the intracellular Ca2+ fluorescence, increasing the mitochondrial membrane potential (Δψ), increasing the expressions of p-38, p-53, Bcl-2, and decreasing the expressions of Bax and active-caspase-3. Conclusion S. tridactyla Sch. Bip.-derived polysaccharides and flavones can reduce cell apoptosis to protect HaCaT cells from oxidative damage after UVB irradiation; however, this effect does not occur via the p38MAPK pathway. PMID:26855564

Protective properties of Huperzine A through activation Nrf2/ARE-mediated transcriptional response in X-rays radiation-induced NIH3T3 cells.

PubMed

Zhu, Huan-Feng; Yan, Peng-Wei; Wang, Li-Jun; Liu, Ya-Tian; Wen, Jing; Zhang, Qian; Fan, Yan-Xin; Luo, Yan-Hong

2018-06-22

Huperzine A (HupA), derived from Huperzia Serrata, has exhibited a variety of biological actions, in particular neuroprotective effect. However, the protective activities of HupA on murine embryonic fibroblast NIH3T3 cells after X-rays radiation have not been fully elucidated. Herein, HupA treatment dramatically promoted cell viability, abated a G0/G1 peak accumulation, and ameliorated increase of cell apoptosis in NIH3T3 cells after X-rays radiation. Simultaneously, HupA notably enhanced activities of anti-oxidant enzymes, inhibited activity of lipid peroxide, and efficiently eliminated production of reactive oxygen species in NIH3T3 cells after X-rays radiation. Dose-dependent increase of antioxidant genes by HupA were associated with up-regulated Nrf2 and down-regulated Keap-1 expression, which was confirmed by increasing nuclear accumulation, and inhibiting of degradation of Nrf2. Notably, augmented luciferase activity of ARE may explained Nrf2/ARE-mediated signaling pathways behind HupA protective properties. Moreover, expression of Nrf2 HupA-mediated was significant attenuated by AKT inhibitor (LY294002), p38 MAPK inhibitor (SB202190) and ERK inhibitor (PD98059). Besides, HupA-mediated cell viability, and ROS production were dramatically bated by LY294002, SB202190, and PD98059. Taken together, HupA effectively ameliorated X-rays radiation-induced damage Nrf2-ARE-mediated transcriptional response via activation AKT, p38, and ERK signaling in NIH3T3 cells. © 2018 Wiley Periodicals, Inc.

Combined Treatment With Peroxisome Proliferator-Activated Receptor (PPAR) Gamma Ligands and Gamma Radiation Induces Apoptosis by PPARγ-Independent Up-Regulation of Reactive Oxygen Species-Induced Deoxyribonucleic Acid Damage Signals in Non-Small Cell Lung Cancer Cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Han, Eun Jong; Im, Chang-Nim; Park, Seon Hwa

2013-04-01

Purpose: To investigate possible radiosensitizing activities of the well-known peroxisome proliferator-activated receptor (PPAR)γ ligand ciglitazone and novel PPARγ ligands CAY10415 and CAY10506 in non-small cell lung cancer (NSCLC) cells. Methods and Materials: Radiosensitivity was assessed using a clonogenic cell survival assay. To investigate the mechanism underlying PPARγ ligand-induced radiosensitization, the subdiploid cellular DNA fraction was analyzed by flow cytometry. Activation of the caspase pathway by combined PPARγ ligands and γ-radiation treatment was detected by immunoblot analysis. Reactive oxygen species (ROS) were measured using 2,7-dichlorodihydrofluorescein diacetate and flow cytometry. Results: The 3 PPARγ ligands induced cell death and ROS generation inmore » a PPARγ-independent manner, enhanced γ-radiation–induced apoptosis and caspase-3–mediated poly (ADP-ribose) polymerase (PARP) cleavage in vitro. The combined PPARγ ligand/γ-radiation treatment triggered caspase-8 activation, and this initiator caspase played an important role in the combination-induced apoptosis. Peroxisome proliferator-activated receptor-γ ligands may enhance the γ-radiation-induced DNA damage response, possibly by increasing γ-H2AX expression. Moreover, the combination treatment significantly increased ROS generation, and the ROS scavenger N-acetylcysteine inhibited the combined treatment-induced ROS generation and apoptotic cell death. Conclusions: Taken together, these results indicated that the combined treatment of PPARγ ligands and γ-radiation synergistically induced DNA damage and apoptosis, which was regulated by ROS.« less

Vitamin D protects keratinocytes from deleterious effects of ionizing radiation.

PubMed

Langberg, M; Rotem, C; Fenig, E; Koren, R; Ravid, A

2009-01-01

Radiotherapy can induce severe skin responses that may limit the clinically acceptable radiation dose. The responses include erythema, dry and moist desquamation, erosions and dermal-epidermal blister formation. These effects reflect injury to, and reproductive failure of, epidermal cells and may also be due to dysregulation of the tissue remodelling process caused by excessive proteolytic activity. Calcitriol, the hormonally active vitamin D metabolite, protects keratinocytes from programmed cell death induced by various noxious stimuli. To examine whether calcitriol protects proliferating keratinocytes from the damage inflicted by ionizing radiation under conditions similar to those employed during radiotherapy. Autonomously proliferating HaCaT keratinocytes, used as a model for basal layer keratinocytes, were irradiated using a linear accelerator. Cell death was monitored by vital staining, executioner caspase activation, lactic dehydrogenase release and colony formation assay. Induction of matrix metalloproteinase-9 was assessed by gelatinase activity assay and mRNA determination. Levels of specific proteins were determined by immunoblotting. Treatment with calcitriol inhibited both caspase-dependent and -independent programmed cell death occurring within 48 h of irradiation and increased the colony formation capacity of irradiated cells. These effects may be attributable to inhibition of the c-Jun NH(2)-terminal kinase cascade and to upregulation of the truncated antiapoptotic isoform of p63. Treatment with the hormone also attenuated radiation-induced increase in matrix metalloproteinase-9 protein and mRNA levels. The results of this study suggest that active vitamin D derivatives may attenuate cell death and excessive proteolytic activity in the epidermis due to exposure to ionizing radiation in the course of radiotherapy.

Molecular mechanism of biological and therapeutical effect of low-intensity laser irradiation

NASA Astrophysics Data System (ADS)

Mostovnikov, Vasili A.; Mostovnikova, Galina R.; Plavski, Vitali Y.; Plavskaja, Ljudmila G.; Morozova, Raisa P.

1995-05-01

The investigations carried out in our group on biological systems of various organization level (enzyme molecules in solution, human and animal cell cultures), allowed us to conclude, that the light-induced changes of spatial structure of cells components form the basis of biological activity (and as a consequence therapeutic effect) of various wavelength low-intensity laser emission. Photophysical mechanism of these changes lies in the reorientation of highregulated anisotropic parts (domains) with the liquid-crystalline type of ordering of the cell components due to the interaction between the electric field and the light induced integral electric dipole of the domain. The mechanism of such reorientation is well established in physics of liquid crystals of nematic type and is known as light induced analogue of Frederix's effect. The following results enable us to draw the conclusion about the determining role of the orientations effects on the biological activity mechanism of low-intensity laser radiation: (i) the possibility of reversible modification of spatial structure and enzyme molecules functional activity under the influence of laser radiation outside the band of their own or admixture absorption; (ii) the dependence of biological effect of laser radiation on the functional activity of cells vs. polarization degree of the light with the maximum photobiological effects observed for linear-polarized radiation; (iii) the equivalence of a static magnetic field and low-intensity laser radiation in action on functional activity of the cells and the lowering of the laser field intensity for the achieving the difinite changes of the cell functional activity in the presence of static magnetic field.

Biophysical principles of regulatory action of low-intensity laser irradiation

NASA Astrophysics Data System (ADS)

Mostovnikov, Vasili A.; Mostovnikova, Galina R.; Plavski, Vitali Y.; Plavskaja, Ljudmila G.

1996-01-01

The investigations carried out in our group on biological systems of various organization level (enzyme molecules in solution, human and animal cell cultures), allowed us to conclude, that the light-induced changes of spatial structure of cells components form the basis of biological activity (and as a consequence therapeutic effect) of various wavelength low-intensity laser emission. Photophysical mechanism of these changes lies in the reorientation of highregulated anisotropic parts (domains) with the liquid-crystalline type of ordering of the cell components due to the interaction between the electric field and the light induced integral electric dipole of the domain. The mechanism of such reorientation is well established in physics of liquid crystals of nematic type and is known as light induced analogue of Frederix's effect. The following results enable us to draw the conclusion about the determining role of the orientations effects on the biological activity mechanism of low-intensity laser radiation: (1) the possibility of reversible modification of spatial structure and enzyme molecules functional activity under the influence of laser radiation outside the band of their own or admixture absorption; (2) the dependence of biological effect of laser radiation on the functional activity of cells vs. polarization degree of the light with the maximum photobiological effects observed for linear-polarized radiation; (3) the equivalence of a static magnetic field and low-intensity laser radiation in action on functional activity of the cells and the lowering of the laser field intensity for the achieving the definite changes of the cell functional activity in the presence of static magnetic field.

Long term dose monitoring onboard the European Columbus module of the international space station (ISS) in the frame of DOSIS and DOSIS 3D project - results from the active instruments

NASA Astrophysics Data System (ADS)

Burmeister, Soenke; Berger, Thomas; Reitz, Guenther; Boehme, Matthias; Haumann, Lutz; Labrenz, Johannes

Besides the effects of the microgravity environment, and the psychological and psychosocial problems encountered in confined spaces, radiation is the main health detriment for long duration human space missions. The radiation environment encountered in space differs in nature from that on earth, consisting mostly of high energetic ions from protons up to iron, resulting in radiation levels far exceeding the ones encountered on earth for occupational radiation workers. Accurate knowledge of the physical characteristics of the space radiation field in dependence on the solar activity, the orbital parameters and the different shielding configurations of the International Space Station ISS is therefore needed. For the investigation of the spatial and temporal distribution of the radiation field inside the European COLUMBUS module the experiment DOSIS (Dose Distribution Inside the ISS) under the lead of DLR has been launched on July 15 (th) 2009 with STS-127 to the ISS. The experimental package was transferred from the Space Shuttle into COLUMBUS on July 18 (th) . It consists of a combination of passive detector packages (PDP) distributed at 11 locations inside the European Columbus Laboratory and two active radiation detectors (Dosimetry Telescopes = DOSTELs) with a DDPU (DOSTEL Data and Power Unit) in a Nomex pouch (DOSIS MAIN BOX) mounted at a fixed location beneath the European Physiology Module rack (EPM) inside COLUMBUS. The active components of the DOSIS experiment were operational from July 18 (th) 2009 to June 16 (th) 2011. After refurbishment the hardware has been reactivated on May 15 (th) 2012 as active part of the DOSIS 3D experiment and provides continuous data since this activation. The presentation will focus on the latest results from the two DOSTEL instruments as absorbed dose, dose equivalent and the related LET spectra gathered within the DOSIS (2009 - 2011) and DOSIS 3D (2012 - 2014) experiment. The CAU contributions to DOSIS and DOSIS 3D are financially supported by BMWi under Grants 50WB0826, 50WB1026 and 50WB1232

Inter- and intra-cellular mechanism of NF-kB-dependent survival advantage and clonal expansion of radio-resistant cancer cells.

PubMed

Yu, Hui; Aravindan, Natarajan; Xu, Ji; Natarajan, Mohan

2017-02-01

Understanding the underlying mechanism by which cancer cells acquire resistance to radiation and favorably selected for its clonal expansion will provide molecular insight into tumor recurrence at the treatment site. In the present study, we investigated the molecular mechanisms prompted in MCF-7 breast cancer cells in response to clinical radiation and the associated coordination of intra- and inter-cellular signaling that orchestrate radio-resistance and tumor relapse/recurrence. Our findings showed that 2 or 10Gy of 137 Cs γ-rays at a dose rate of 1.03Gy/min trigger the activation of nuclear factor kappa B (NF-κB), its DNA-binding activity and recycles its own transcription. NF-κB DNA-binding kinetic analysis demonstrated both sustained and dual phase NF-κB activation with radiation. Gene manipulation approach revealed that radiation triggered NF-κB-mediated TNF-α transcriptional activity. TNF-α blocking approach confirmed that the de novo synthesis and secretion of TNF-α serves as a pre-requisite for the second phase of NF-κB activation and sustained maintenance. Radiation-associated NF-κB-dependent secretion of TNF-α from irradiated cells, in parallel, activates NF-κB in the non-targeted un-irradiated bystander cells. Together, these findings demonstrated that radiation-triggered NF-κB-dependent TNFα secretion is critical for self-sustenance of NF-κB (through autocrine positive feedback signaling) and for coordinating bystander response (through inter-cellular paracrine mechanism) after radiation exposure. Further, the data suggest that this self-sustained NF-κB in the irradiated cells determines radio-resistance, survival advantage and clonal expansion of the tumor cells at the treatment site. Parallel maintenance of NF-ΚB-TNF-α-NF-κB feedback-cycle in the un-irradiated non-targeted bystander cells initiates supportive mechanism for the promotion and progression of surviving tumor cells. Intervening this molecular pathway would help us to achieve disease-free cancer survivors. Copyright © 2017 Elsevier Inc. All rights reserved.

Cellular Internalization of Fibroblast Growth Factor-12 Exerts Radioprotective Effects on Intestinal Radiation Damage Independently of FGFR Signaling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nakayama, Fumiaki, E-mail: f_naka@nirs.go.jp; Umeda, Sachiko; Yasuda, Takeshi

2014-02-01

Purpose: Several fibroblast growth factors (FGFs) were shown to inhibit radiation-induced tissue damage through FGF receptor (FGFR) signaling; however, this signaling was also found to be involved in the pathogenesis of several malignant tumors. In contrast, FGF12 cannot activate any FGFRs. Instead, FGF12 can be internalized readily into cells using 2 cell-penetrating peptide domains (CPP-M, CPP-C). Therefore, this study focused on clarifying the role of FGF12 internalization in protection against radiation-induced intestinal injury. Methods and Materials: Each FGF or peptide was administered intraperitoneally to BALB/c mice in the absence of heparin 24 hours before or after total body irradiation withmore » γ rays at 9 to 12 Gy. Several radioprotective effects were examined in the jejunum. Results: Administration of FGF12 after radiation exposure was as effective as pretreatment in significantly promoting intestinal regeneration, proliferation of crypt cells, and epithelial differentiation. Two domains, comprising amino acid residues 80 to 109 and 140 to 169 of FGF12B, were identified as being responsible for the radioprotective activity, so that deletion of both domains from FGF12B resulted in a reduction in activity. Interestingly, these regions included the CPP-M and CPP-C domains, respectively; however, CPP-C by itself did not show an antiapoptotic effect. In addition, FGF1, prototypic FGF, possesses a domain corresponding to CPP-M, whereas it lacks CPP-C, so the fusion of FGF1 with CPP-C (FGF1/CPP-C) enhanced cellular internalization and increased radioprotective activity. However, FGF1/CPP-C reduced in vitro mitogenic activity through FGFRs compared with FGF1, implying that FGFR signaling might not be essential for promoting the radioprotective effect of FGF1/CPP-C. In addition, internalized FGF12 suppressed the activation of p38α after irradiation, resulting in reduced radiation-induced apoptosis. Conclusions: These findings indicate that FGF12 can protect the intestine against radiation-induced injury through its internalization, independently of FGFRs, suggesting that cellular uptake of FGF12 is an alternative signaling pathway useful for cancer radiation therapy.« less

Effects of Proton and Combined Proton and (56)Fe Radiation on the Hippocampus.

PubMed

Raber, Jacob; Allen, Antiño R; Sharma, Sourabh; Allen, Barrett; Rosi, Susanna; Olsen, Reid H J; Davis, Matthew J; Eiwaz, Massarra; Fike, John R; Nelson, Gregory A

2016-01-01

The space radiation environment contains protons and (56)Fe, which could pose a significant hazard to space flight crews during and after missions. The space environment involves complex radiation exposures, thus, the effects of a dose of protons might be modulated by a dose of heavy-ion radiation. The brain, and particularly the hippocampus, may be susceptible to space radiation-induced changes. In this study, we first determined the dose-response effect of proton radiation (150 MeV) on hippocampus-dependent cognition 1 and 3 months after exposure. Based on those results, we subsequently exposed mice to protons alone (150 MeV, 0.1 Gy), (56)Fe alone (600 MeV/n, 0.5 Gy) or combined proton and (56)Fe radiations (protons first) with the two exposures separated by 24 h. At one month postirradiation, all animal groups showed novel object recognition. However, at three months postirradiation, mice exposed to either protons or combined proton and (56)Fe radiations showed impaired novel object recognition, which was not observed in mice irradiated with (56)Fe alone. The mechanisms in these impairments might involve inflammation. In mice irradiated with protons alone or (56)Fe alone three months earlier, there was a negative correlation between a measure of novel object recognition and the number of newly born activated microglia in the dentate gyrus. Next, cytokine and chemokine levels were assessed in the hippocampus. At one month after exposure the levels of IL-12 were higher in mice exposed to combined radiations compared with sham-irradiated mice, while the levels of IFN-γ were lower in mice exposed to (56)Fe radiation alone or combined radiations. In addition, IL-4 levels were lower in (56)Fe-irradiated mice compared with proton-irradiated mice and TNF-α levels were lower in proton-irradiated mice than in mice receiving combined radiations. At three months after exposure, macrophage-derived chemokine (MDC) and eotaxin levels were lower in mice receiving combined radiations. The levels of MDC and eotaxin correlated and the levels of MDC, but not eotaxin, correlated with the percentage of newly born activated microglia in the blades of the dentate gyrus. Finally, hippocampal IL-6 levels were higher in mice receiving combined radiations compared with mice receiving (56)Fe radiation alone. These data demonstrate the sensitivity of novel object recognition for detecting cognitive injury three months after exposure to proton radiation alone, and combined exposure to proton and (56)Fe radiations, and that newly-born activated microglia and inflammation might be involved in this injury.

Monocyte galactose/N-acetylgalactosamine-specific C-type lectin receptor stimulant immunotherapy of an experimental glioma. Part II: combination with external radiation improves survival

PubMed Central

Kushchayev, Sergiy V; Sankar, Tejas; Eggink, Laura L; Kushchayeva, Yevgeniya S; Wiener, Philip C; Hoober, J Kenneth; Eschbacher, Jennifer; Liu, Ruolan; Shi, Fu-Dong; Abdelwahab, Mohammed G; Scheck, Adrienne C; Preul, Mark C

2012-01-01

Background A peptide mimetic of a ligand for the galactose/N-acetylgalactosamine-specific C-type lectin receptors (GCLR) exhibited monocyte-stimulating activity, but did not extend survival when applied alone against a syngeneic murine malignant glioma. In this study, the combined effect of GCLRP with radiation was investigated. Methods C57BL/6 mice underwent stereotactic intracranial implantation of GL261 glioma cells. Animals were grouped based on randomized tumor size by magnetic resonance imaging on day seven. One group that received cranial radiation (4 Gy on days seven and nine) only were compared with animals treated with radiation and GCLRP (4 Gy on days seven and nine combined with subcutaneous injection of 1 nmol/g on alternative days beginning on day seven). Magnetic resonance imaging was used to assess tumor growth and correlated with survival rate. Blood and brain tissues were analyzed with regard to tumor and contralateral hemisphere using fluorescence-activated cell sorting analysis, histology, and enzyme-linked immunosorbent assay. Results GCLRP activated peripheral monocytes and was associated with increased blood precursors of dendritic cells. Mean survival increased (P < 0.001) and tumor size was smaller (P < 0.02) in the GCLRP + radiation group compared to the radiation-only group. Accumulation of dendritic cells in both the tumoral hemisphere (P < 0.005) and contralateral tumor-free hemisphere (P < 0.01) was associated with treatment. Conclusion Specific populations of monocyte-derived brain cells develop critical relationships with malignant gliomas. The biological effect of GCLRP in combination with radiation may be more successful because of the damage incurred by tumor cells by radiation and the enhanced or preserved presentation of tumor cell antigens by GCLRP-activated immune cells. Monocyte-derived brain cells may be important targets for creating effective immunological modalities such as employing the receptor system described in this study. PMID:23049281

Monocyte galactose/N-acetylgalactosamine-specific C-type lectin receptor stimulant immunotherapy of an experimental glioma. Part II: combination with external radiation improves survival.

PubMed

Kushchayev, Sergiy V; Sankar, Tejas; Eggink, Laura L; Kushchayeva, Yevgeniya S; Wiener, Philip C; Hoober, J Kenneth; Eschbacher, Jennifer; Liu, Ruolan; Shi, Fu-Dong; Abdelwahab, Mohammed G; Scheck, Adrienne C; Preul, Mark C

2012-01-01

A peptide mimetic of a ligand for the galactose/N-acetylgalactosamine-specific C-type lectin receptors (GCLR) exhibited monocyte-stimulating activity, but did not extend survival when applied alone against a syngeneic murine malignant glioma. In this study, the combined effect of GCLRP with radiation was investigated. C57BL/6 mice underwent stereotactic intracranial implantation of GL261 glioma cells. Animals were grouped based on randomized tumor size by magnetic resonance imaging on day seven. One group that received cranial radiation (4 Gy on days seven and nine) only were compared with animals treated with radiation and GCLRP (4 Gy on days seven and nine combined with subcutaneous injection of 1 nmol/g on alternative days beginning on day seven). Magnetic resonance imaging was used to assess tumor growth and correlated with survival rate. Blood and brain tissues were analyzed with regard to tumor and contralateral hemisphere using fluorescence-activated cell sorting analysis, histology, and enzyme-linked immunosorbent assay. GCLRP activated peripheral monocytes and was associated with increased blood precursors of dendritic cells. Mean survival increased (P < 0.001) and tumor size was smaller (P < 0.02) in the GCLRP + radiation group compared to the radiation-only group. Accumulation of dendritic cells in both the tumoral hemisphere (P < 0.005) and contralateral tumor-free hemisphere (P < 0.01) was associated with treatment. Specific populations of monocyte-derived brain cells develop critical relationships with malignant gliomas. The biological effect of GCLRP in combination with radiation may be more successful because of the damage incurred by tumor cells by radiation and the enhanced or preserved presentation of tumor cell antigens by GCLRP-activated immune cells. Monocyte-derived brain cells may be important targets for creating effective immunological modalities such as employing the receptor system described in this study.

The Study of External Dose Rate and Retained Body Activity of Patients Receiving 131I Therapy for Differentiated Thyroid Carcinoma

PubMed Central

Zhang, Haiying; Jiao, Ling; Cui, Songye; Wang, Liang; Tan, Jian; Zhang, Guizhi; He, Yajing; Ruan, Shuzhou; Fan, Saijun; Zhang, Wenyi

2014-01-01

Radiation safety is an integral part of targeted radionuclide therapy. The aim of this work was to study the external dose rate and retained body activity as functions of time in differentiated thyroid carcinoma patients receiving 131I therapy. Seventy patients were stratified into two groups: the ablation group (A) and the follow-up group (FU). The patients’ external dose rate was measured, and simultaneously, their retained body radiation activity was monitored at various time points. The equations of the external dose rate and the retained body activity, described as a function of hours post administration, were fitted. Additionally, the release time for patients was calculated. The reduction in activity in the group receiving a second or subsequent treatment was more rapid than the group receiving only the initial treatment. Most important, an expeditious method was established to indirectly evaluate the retained body activity of patients by measuring the external dose rate with a portable radiation survey meter. By this method, the calculated external dose rate limits are 19.2, 8.85, 5.08 and 2.32 μSv·h−1 at 1, 1.5, 2 and 3 m, respectively, according to a patient’s released threshold level of retained body activity <400 MBq. This study is beneficial for radiation safety decision-making. PMID:25337944

Influences of photosynthetically active radiation on cladode orientation, stem tilting, and height of cacti

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nobel, P.S.

1981-08-01

Stem orientation and morphology were investigated for 14 species of cacti in Chile, Ecuador, Mexico, and the United States. The interception of photosynthetically active radiation (PAR) was specifically considered for cladodes (flattened stems) of platyopuntias, for tilted cylindrical stems, and in the presence of surrounding vegetation.

Experimental active and passive dosimetry systems for the NASA Skylab program

NASA Technical Reports Server (NTRS)

Schneider, M. F.; Janni, J. F.; Ainsworth, G. C.

1972-01-01

Active and passive dosimetry instrumentation to measure absorbed dose, charged particle spectra, and linear energy transfer spectra inside the command module and orbital workshop on the Skylab program were developed and tested. The active dosimetry system consists of one integral unit employing both a tissue equivalent ionization chamber and silicon solid state detectors. The instrument measures dose rates from 0.2 millirad/hour to 25 rads/hour, linear energy transfer spectra from 2.8 to 42.4 Kev/micron, and the proton and alpha particle energy spectra from 0.5 to 75 Mev. The active dosimeter is equipped with a portable radiation sensor for use in astronaut on-body and spacecraft shielding surveys during passage of the Skylab through significant space radiations. Data are transmitted in real time or are recorded by onboard spacecraft tape recorder for rapid evaluation of the radiation levels. The passive dosimetry systems consist of twelve (12) hard-mounted assemblies, each containing a variety of passive radiation sensors which are recoverable at the end of the mission for analysis.

Gamma Radiation Effects on Peanut Skin Antioxidants

PubMed Central

de Camargo, Adriano Costa; de Souza Vieira, Thais Maria Ferreira; Regitano-D’Arce, Marisa Aparecida Bismara; Calori-Domingues, Maria Antonia; Canniatti-Brazaca, Solange Guidolin

2012-01-01

Peanut skin, which is removed in the peanut blanching process, is rich in bioactive compounds with antioxidant properties. The aims of this study were to measure bioactive compounds in peanut skins and evaluate the effect of gamma radiation on their antioxidant activity. Peanut skin samples were treated with 0.0, 5.0, 7.5, or 10.0 kGy gamma rays. Total phenolics, condensed tannins, total flavonoids, and antioxidant activity were evaluated. Extracts obtained from the peanut skins were added to refined-bleached-deodorized (RBD) soybean oil. The oxidative stability of the oil samples was determined using the Oil Stability Index method and compared to a control and synthetic antioxidants (100 mg/kg BHT and 200 mg/kg TBHQ). Gamma radiation changed total phenolic content, total condensed tannins, total flavonoid content, and the antioxidant activity. All extracts, gamma irradiated or not, presented increasing induction period (h), measured by the Oil Stability Index method, when compared with the control. Antioxidant activity of the peanut skins was higher than BHT. The present study confirmed that gamma radiation did not affect the peanut skin extracts’ antioxidative properties when added to soybean oil. PMID:22489142

Occupational external exposure to ionising radiation in France (2005-2011).

PubMed

Feuardent, J; Scanff, P; Crescini, D; Rannou, A

2013-12-01

The Institute for Radiological Protection and Nuclear Safety (IRSN) produces the French annual report on occupational exposure to ionising radiation, collecting all national data and aggregating the results according to a unique activity classification expected to be shared by all involved in personal dosimetric monitoring (employers, external dosimetry services and IRSN). Nearly 344,000 monitored workers were counted in France in 2011, with a collective dose of 64.24 man.Sv. The average annual dose (as calculated over the number of measurably exposed workers) differed among the main activity fields: 0.54 mSv in medical and veterinary activities, 1.18 mSv in the nuclear field, 1.60 mSv in non-nuclear industry and 0.47 mSv in research activities. Because of improved knowledge about worker activities, the results for year 2011 are detailed per activity sectors in each field. Lasting limitations prevent from having complete and reliable worker activity information. Solutions are considered to reduce the inaccuracy in the annually published statistics. The evolution of occupational external exposure to ionising radiation from 2005 to 2011 in France is then presented for the main activity fields.

Subtype-Specific Radiation Response and Therapeutic Effect of FAS Death Receptor Modulation in Human Breast Cancer.

PubMed

Lee, Chen-Ting; Zhou, Yingchun; Roy-Choudhury, Kingshuk; Siamakpour-Reihani, Sharareh; Young, Kenneth; Hoang, Peter; Kirkpatrick, John P; Chi, Jen-Tsan A; Dewhirst, Mark W; Horton, Janet K

2017-08-01

Breast cancer is the most common malignancy diagnosed among women and represents a heterogeneous group of subtypes. Radiation therapy is a critical component of treatment for breast cancer patients. However, little is known about radiation response among these intrinsic subtypes. In previous studies, we identified a significant induction of FAS after irradiation in biologically favorable breast cancer patients and breast cancer cell lines. Here, we expanded our study and investigated radiation response in a mouse model of breast cancer. MCF7 (luminal), HCC1954 (HER2 + ) or SUM159 (basal) cells were implanted orthotopically into the dorsal mammary fat pad of nude mice. These mice were then treated with different doses of radiation to assess tumor growth control. We further investigated the therapeutic effect of FAS modulation by silencing FAS in radiation-responsive tumors and injecting FAS agonist antibody into radiation-resistant tumors. Exposure to radiation inhibited MCF7, and to a lesser extent HCC1954 tumor growth in a dose-dependent manner. In contrast, SUM159 tumors were resistant to radiation. The estimated TCD 50 values were 19.3 Gy for MCF7 and 44.9 Gy for SUM159. Radiation induced FAS expression in MCF7 tumors, but not SUM159 tumors. We found that silencing of FAS did not negatively impact radiation response in MCF7 tumors, possibly due to compensation by other apoptotic pathways. On the other hand, FAS activating antibody in combination with radiation treatment delayed SUM159 and HCC1954 tumor growth. However, it did not reach statistical significance compared to radiation treatment alone. Our results suggest that there is intrinsic variation in radiation response among breast cancer subtypes. FAS activation concurrent with radiation slows tumor growth in the radiation-resistant subtypes, but the effect was not significant. Alternative subtype-specific modulators of radiation response are under investigation.

Nuclear fuel pin scanner

DOEpatents

Bramblett, Richard L.; Preskitt, Charles A.

1987-03-03

Systems and methods for inspection of nuclear fuel pins to determine fiss loading and uniformity. The system includes infeed mechanisms which stockpile, identify and install nuclear fuel pins into an irradiator. The irradiator provides extended activation times using an approximately cylindrical arrangement of numerous fuel pins. The fuel pins can be arranged in a magazine which is rotated about a longitudinal axis of rotation. A source of activating radiation is positioned equidistant from the fuel pins along the longitudinal axis of rotation. The source of activating radiation is preferably oscillated along the axis to uniformly activate the fuel pins. A detector is provided downstream of the irradiator. The detector uses a plurality of detector elements arranged in an axial array. Each detector element inspects a segment of the fuel pin. The activated fuel pin being inspected in the detector is oscillated repeatedly over a distance equal to the spacing between adjacent detector elements, thereby multiplying the effective time available for detecting radiation emissions from the activated fuel pin.

A novel research model for evaluating sunscreen protection in the UV-A1.

PubMed

Figueiredo, Sônia Aparecida; de Moraes, Dayane Cristina; Vilela, Fernanda Maria Pinto; de Faria, Amanda Natalina; Dos Santos, Marcelo Henrique; Fonseca, Maria José Vieira

2018-01-01

The use of a broad spectrum sunscreen is considered one of the main and most popular measures for preventing the damaging effects of ultraviolet radiation (UVR) on the skin. In this study we have developed a novel in vitro method to assess sunscreens efficacy to protect calcineurin enzyme activity, a skin cell marker. The photoprotective efficacy of sunscreen products was assessed by measuring the UV-A1 radiation-induced depletion of calcineurin (Cn) enzyme activity in primary neonatal human dermal fibroblast (HDFn) cell lysates. After exposure to 24J/cm 2 UV-A1 radiation, the sunscreens containing larger amounts of UV-A1 filters (brand B), the astaxanthin (UV-A1 absorber) and the Tinosorb® M (UV-A1 absorber) were capable of preventing loss of Cn activity when compared to the sunscreens formulations of brand A (low concentration of UV-A1 filters), with the Garcinia brasiliensis extract (UV-B absorber) and with the unprotected cell lysate and exposed to irradiation (Irradiated Control - IC). The Cn activity assay is a reproducible, accurate and selective technique for evaluating the effectiveness of sunscreens against the effects of UV-A1 radiation. The developed method showed that calcineurin activity have the potential to act as a biological indicator of UV-A1 radiation-induced damages in skin and the assay might be used to assess the efficacy of sunscreens agents and plant extracts prior to in vivo tests. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of enhanced UV-B radiation on the diversity and activity of soil microorganism of alpine meadow ecosystem in Qinghai-Tibet Plateau.

PubMed

Niu, Fujun; He, Junxia; Zhang, Gaosen; Liu, Xiaomei; Liu, Wei; Dong, Maoxing; Wu, Fasi; Liu, Yongjun; Ma, Xiaojun; An, Lizhe; Feng, Huyuan

2014-12-01

The effects of enhanced UV-B radiation on abundance, community composition and the total microbial activity of soil bacteria in alpine meadow ecosystem of Qinghai-Tibet Plateau were investigated. Traditional counting and 16S rRNA gene sequencing were used to investigate the culturable bacteria and their composition in soil, meanwhile the total microbial activity was measured by microcalorimetry. The population of soil culturable bacteria was slightly reduced with the enhanced UV-B radiation in both of the two depths, 2.46 × 10(6) CFU/g in upper layer (0-10 cm), 1.44 × 10(6) CFU/g in under layer (10-20 cm), comparing with the control (2.94 × 10(6) CFU/g in upper layer, 1.65 × 10(6) CFU/g in under layer), although the difference was not statistically significant (P > 0.05). However, the bacteria diversity decreased obviously due to enhanced UV-B, the number of species for upper layer was decreased from 20 to 13, and from 16 to 13 for the lower layer. The distribution of species was also quite different between the two layers. Another obvious decrease induced by enhanced UV-B radiation was in the total soil microbial activities, which was represented by the microbial growth rate constant (k) in this study. The results indicated that the culturable bacteria community composition and the total activity of soil microbes have been considerably changed by the enhanced UV-B radiation.

[Variations of solar activity and radiation situation on board MIR station during the period 1986-1994].

PubMed

Bondarenko, V A; Mitrikas, V G; Tsetlin , V V

1995-01-01

This paper is dedicated to the analysis of the radiation situation onboard Mir station over a period of 1986-1994, there examined the main cosmophysics parameters and indices of the solar activity as well as the variations of the parameters of the earth's magnetic field and their association with the changes in the power of absorbed dose onboard the station. There noted the high levels of radiation exposure to the cosmonauts under terrestrial conditions when carrying out the roentgeno-radiologic examinations and procedures comparable or exceeding the absorbed doses during the flights. For revealing the regular associations of the radiation situation onboard the station with the parameters of solar activity there has been analyzed the time changes of average monthly values of dose power since the beginning of station functioning in 1986 until returning the fifteenth expedition to Earth. From the analyses of the results it might be assumed that the best statistical associations of average monthly power of the absorbed dose are found with the streams of protons of GCR. Wolff numbers and background stream of the radio emission of the Sun which reflects the existence of the radiation situation upon the phase of solar activity cycle. From this paper it transpires that calculating the dose loads during the period of the extreme phases of solar activity, it is possible to make between them the interpolations of time dependence by analogy with the dynamics in time of the background streams of GCR or Wolff numbers.

76 FR 29010 - Agency Information Collection Activities; Submission for OMB Review; Comment Request; Ionizing...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-19

... for OMB Review; Comment Request; Ionizing Radiation Standard ACTION: Notice. SUMMARY: The Department... information collection request (ICR) titled, ``Ionizing Radiation Standard,'' to the Office of Management and... provisions of the Ionizing Radiation Standard specify paperwork requirements, including: Monitoring of worker...

Ionizing radiation induces O6-alkylguanine-DNA-alkyltransferase mRNA and activity in mouse tissues.

PubMed

Wilson, R E; Hoey, B; Margison, G P

1993-04-01

The effect of exposure to whole-body gamma-irradiation or fast electrons on O6-alkylguanine-DNA-alkyltransferase (ATase) activity and mRNA abundance has been examined in mice. In response to gamma-radiation, hepatic ATase activity was significantly raised in BDF1 mice 24 h post-irradiation, reaching a maximum of 2- to 3-fold at 36 h and beginning to decrease by 48-60 h. A small but consistently higher level of induction was achieved when mice were exposed using a low dose rate (0.015 Gy/min) compared to a high dose rate (0.5 Gy/min). ATase activity was also induced approximately 2-fold 48 h post-irradiation in brain, kidney, lung and spleen, with a greater induction again observed in response to the lower dose rate. In response to fast electrons from a linear accelerator hepatic ATase activity was also induced 2- to 3-fold 48 h post-irradiation in BDF1, BALB/c, C57Bl and DBA2 strains. Induction of ATase activity in livers of BDF1 mice was observed 48 h after a total single dose of 5 Gy gamma-radiation (2-fold), increasing to a slightly higher level at 15 Gy, but no induction was observed at doses of 2 Gy and below. Although a maximum 2- to 3-fold induction of ATase activity was observed, mRNA levels were induced 3- to 4-fold by 48 h after a dose of 15 Gy. Furthermore, significant increases in mRNA levels were detected at low doses (1-2 Gy) at which there was no apparent increase in ATase activity. This suggests that ionizing radiation increases ATase levels by a process involving transcriptional upregulation but that strong post-transcriptional and/or translational controls operate to limit induction of enzyme activity to 2- to 3-fold. This is the first report of an in vivo induction of ATase by ionizing radiation in a species other than the rat.

RESEARCH ACTIVITIES IN THE FIELD OF MATERIALS SCIENCE.

DTIC Science & Technology

MAGNETIC RESONANCE, COMPLEX COMPOUNDS, CRYSTAL STRUCTURE, ELECTROCHEMISTRY, CHEMILUMINESCENCE, PHOTOCHEMICAL REACTIONS, PHOSPHORUS HETEROCYCLIC COMPOUNDS...RADIATION CHEMISTRY, POLYMERS, ROCK, SUPERCONDUCTORS, POSITRONS , DAMAGE, RADIATION EFFECTS, HALIDES

Analysis of Radiation Transport Due to Activated Coolant in the ITER Neutral Beam Injection Cell

DOE Office of Scientific and Technical Information (OSTI.GOV)

Royston, Katherine; Wilson, Stephen C.; Risner, Joel M.

Detailed spatial distributions of the biological dose rate due to a variety of sources are required for the design of the ITER tokamak facility to ensure that all radiological zoning limits are met. During operation, water in the Integrated loop of Blanket, Edge-localized mode and vertical stabilization coils, and Divertor (IBED) cooling system will be activated by plasma neutrons and will flow out of the bioshield through a complex system of pipes and heat exchangers. This paper discusses the methods used to characterize the biological dose rate outside the tokamak complex due to 16N gamma radiation emitted by the activatedmore » coolant in the Neutral Beam Injection (NBI) cell of the tokamak building. Activated coolant will enter the NBI cell through the IBED Primary Heat Transfer System (PHTS), and the NBI PHTS will also become activated due to radiation streaming through the NBI system. To properly characterize these gamma sources, the production of 16N, the decay of 16N, and the flow of activated water through the coolant loops were modeled. The impact of conservative approximations on the solution was also examined. Once the source due to activated coolant was calculated, the resulting biological dose rate outside the north wall of the NBI cell was determined through the use of sophisticated variance reduction techniques. The AutomateD VAriaNce reducTion Generator (ADVANTG) software implements methods developed specifically to provide highly effective variance reduction for complex radiation transport simulations such as those encountered with ITER. Using ADVANTG with the Monte Carlo N-particle (MCNP) radiation transport code, radiation responses were calculated on a fine spatial mesh with a high degree of statistical accuracy. In conclusion, advanced visualization tools were also developed and used to determine pipe cell connectivity, to facilitate model checking, and to post-process the transport simulation results.« less

Analysis of Radiation Transport Due to Activated Coolant in the ITER Neutral Beam Injection Cell

DOE PAGES

Royston, Katherine; Wilson, Stephen C.; Risner, Joel M.; ...

2017-07-26

Detailed spatial distributions of the biological dose rate due to a variety of sources are required for the design of the ITER tokamak facility to ensure that all radiological zoning limits are met. During operation, water in the Integrated loop of Blanket, Edge-localized mode and vertical stabilization coils, and Divertor (IBED) cooling system will be activated by plasma neutrons and will flow out of the bioshield through a complex system of pipes and heat exchangers. This paper discusses the methods used to characterize the biological dose rate outside the tokamak complex due to 16N gamma radiation emitted by the activatedmore » coolant in the Neutral Beam Injection (NBI) cell of the tokamak building. Activated coolant will enter the NBI cell through the IBED Primary Heat Transfer System (PHTS), and the NBI PHTS will also become activated due to radiation streaming through the NBI system. To properly characterize these gamma sources, the production of 16N, the decay of 16N, and the flow of activated water through the coolant loops were modeled. The impact of conservative approximations on the solution was also examined. Once the source due to activated coolant was calculated, the resulting biological dose rate outside the north wall of the NBI cell was determined through the use of sophisticated variance reduction techniques. The AutomateD VAriaNce reducTion Generator (ADVANTG) software implements methods developed specifically to provide highly effective variance reduction for complex radiation transport simulations such as those encountered with ITER. Using ADVANTG with the Monte Carlo N-particle (MCNP) radiation transport code, radiation responses were calculated on a fine spatial mesh with a high degree of statistical accuracy. In conclusion, advanced visualization tools were also developed and used to determine pipe cell connectivity, to facilitate model checking, and to post-process the transport simulation results.« less

Radiation hazards of radio frequency waves on the early embryonic development of Zebrafish

NASA Astrophysics Data System (ADS)

Harkless, Ryan; Al-Quraishi, Muntather; Vagula, Mary C.

2014-06-01

With the growing use of wireless devices in almost all day-to-day activities, exposure to radio-frequency radiation has become an immediate health concern. It is imperative that the effects of such radiation not only on humans, but also on other organisms be well understood. In particular, it is critical to understand if RF radiation has any bearing on the gene expression during embryonic development, as this is a crucial and delicate phase for any organism. Owing to possible effects that RF radiation may have on gene expression, it is essential to explore the carcinogenic or teratogenic properties that it may show. This study observed the effects of RF radiation emitted from a cellular telephone on the embryonic development of zebra fish. The expression of the gene shha plays a key role in the early development of the fish. This gene has homologs in humans as well as in other model organisms. Additionally, several biomarkers indicative of cell stress were examined: including lactate dehydrogenase (LDH), superoxide dismutase (SOD), and lipid peroxidation (LPO). Results show a significant decrease in the expression of shha, a significant decrease in LDH activity. There was no significant increase in SOD and LPO activity. No morphological abnormalities were observed in the developing embryos. At present, these results indicate that exposure to cell phone radiation may have a suppressive effect on expression of shha in D. rerio, though such exposure does not appear to cause morphological detriments. More trials are underway to corroborate these results.

Manned Mars mission radiation environment and radiobiology

NASA Technical Reports Server (NTRS)

Nachtwey, D. S.

1986-01-01

Potential radiation hazards to crew members on manned Mars missions are discussed. It deals briefly with radiation sources and environments likely to be encountered during various phases of such missions, providing quantitative estimates of these environments. Also provided are quantitative data and discussions on the implications of such radiation on the human body. Various sorts of protective measures are suggested. Recent re-evaluation of allowable dose limits by the National Council of Radiation Protection is discussed, and potential implications from such activity are assessed.

The radiation asymmetry in MGI rapid shutdown on J-TEXT tokamak

NASA Astrophysics Data System (ADS)

Tong, Ruihai; Chen, Zhongyong; Huang, Duwei; Cheng, Zhifeng; Zhang, Xiaolong; Zhuang, Ge; J-TEXT Team

2017-10-01

Disruptions, the sudden termination of tokamak fusion plasmas by instabilities, have the potential to cause severe material wall damage to large tokamaks like ITER. The mitigation of disruption damage is an essential part of any fusion reactor system. Massive gas injection (MGI) rapid shutdown is a technique in which large amounts of noble gas are injected into the plasma in order to safely radiate the plasma energy evenly over the entire plasma-facing first wall. However, the radiated energy during the thermal quench (TQ) in massive gas injection (MGI) induced disruptions is found toroidal asymmetric, and the degrees of asymmetry correlate with the gas penetration and MGI induced magnetohydrodynamics (MHD) activities. A toroidal and poloidal array of ultraviolet photodiodes (AXUV) has been developed to investigate the radiation asymmetry on J-TEXT tokamak. Together with the upgraded mirnov probe arrays, the relation between MGI triggered MHD activities with radiation asymmetry is studied.

In-flight shortwave calibrations of the active cavity radiometers using tungsten lamps

NASA Technical Reports Server (NTRS)

Thomas, Susan; Lee, Robert B.; Gibson, Michael A.; Wilson, Robert S.; Bolden, William C.

1992-01-01

The Earth Radiation Budget Experiment (ERBE) active cavity radiometers are used to measure the incoming solar, reflected shortwave solar, and emitted longwave radiations from the Earth and atmosphere. The radiometers are located on the NASA's Earth Radiation Budget Satellite (ERBS) and the NOAA-9 and NOAA-10 spacecraft platforms. Two of the radiometers, one wide field of view (WFOV) and one medium field of view (MFOV), measure the total radiation in the spectral region of 0.2 to 50 microns and the other two radiometers (WFOV and MFOV) measure the shortwave radiation in the spectral region of 0.2 to 5.0 microns. For the in-flight calibrations, tungsten lamp and the sun are used as calibration sources for shortwave radiometers. Descriptions of the tungsten lamp and solar calibration procedures and mechanisms are presented. The tungsten lamp calibration measurements are compared with the measurements of solar calibration for ERBS and NOAA-9 instruments.

Measurement of surface physical properties and radiation balance for KUREX-91 study

NASA Technical Reports Server (NTRS)

Walter-Shea, Elizabeth A.; Blad, Blaine L.; Mesarch, Mark A.; Hays, Cynthia J.

1992-01-01

Biophysical properties and radiation balance components were measured at the Streletskaya Steppe Reserve of the Russian Republic in July 1991. Steppe vegetation parameters characterized include leaf area index (LAI), leaf angle distribution, mean tilt angle, canopy height, leaf spectral properties, leaf water potential, fraction of absorbed photosynthetically active radiation (APAR), and incoming and outgoing shortwave and longwave radiation. Research results, biophysical parameters, radiation balance estimates, and sun-view geometry effects on estimating APAR are discussed. Incoming and outgoing radiation streams are estimated using bidirectional spectral reflectances and bidirectional thermal emittances. Good agreement between measured and modeled estimates of the radiation balance were obtained.

Estimation of land photosynthetically active radiation in clear sky using MODIS atmosphere and land products

NASA Astrophysics Data System (ADS)

Xie, Xiaoping; Gao, Wei; Gao, Zhiqiang

2008-08-01

Photosynthetically active radiation (PAR) is an essential parameter in vegetation growth model and soil carbon sequestration models. A method is presented with which instantaneous PAR can be calculated with high accuracy from Moderate Resolution Imaging Spectroradiometer (MODIS) atmosphere and land products. The method is based on a simplification of the general radiative transfer equation, which considers five major processes of attenuation of solar radiation: Rayleigh scattering, absorption by ozone and water vapor, aerosol scattering, multiply reflectance between surface and atmosphere. Comparing 108 retrieveled results to filed measured PAR in Yucheng station of Chinese Ecosystem Research Network (CERN) in 2006, and the r-square of 0.855 indicates that the computed results can interpret actual PAR well.

NASA Crew Personal Active Dosimeters (CPADs): Leveraging Novel Terrestrial Personal Radiation Monitoring Capabilities for Space Exploration

NASA Technical Reports Server (NTRS)

Leitgab, Martin; Semones, Edward; Lee, Kerry

2016-01-01

The NASA Space Radiation Analysis Group (SRAG) is developing novel Crew Personal Active Dosimeters (CAPDs) for upcoming crewed space exploration missions and beyond. To reduce the resource footprint of the project a COTS dosimeter base is used for the development of CPADs. This base was identified from evaluations of existing COTS personal dosimeters against the concept of operations of future crewed missions and tests against detection requirements for radiation characteristic of the space environment. CPADs exploit operations efficiencies from novel features for space flight personal dosimeters such as real-time dose feedback, and autonomous measuring and data transmission capabilities. Preliminary CPAD design, results of radiation testing and aspects of operational integration will be presented.

Federal Guidance Report No. 2: Background Material for the Development of Radiation Protection Standards (Federal Radiation Council)

EPA Pesticide Factsheets

This report discusses how to provide guidance for Federal agencies in activities designed to limit exposure of members of population groups to radiation from radioactive materials deposited in the body as a result of their occurrence in the environment.

BEIR-III report and its implications for radiation protection and public health policy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fabrikant, J.I.

1980-03-01

A general background is given of the implications the BEIR-III Report may have on societal decision-making in the regulation of activities concerned with the health effects of low-level radiation. The scientific basis for establishing appropriate radiation protection guides are discussed. (ACR)

Space radiation protection: Human support thrust exploration technology program

NASA Technical Reports Server (NTRS)

Conway, Edmund J.

1991-01-01

Viewgraphs on space radiation protection are presented. For crew and practical missions, exploration requires effective, low-mass shielding and accurate estimates of space radiation exposure for lunar and Mars habitat shielding, manned space transfer vehicle, and strategies for minimizing exposure during extravehicular activity (EVA) and rover operations.

Assessing exposure to granite countertops--Part 1: Radiation.

PubMed

Myatt, Theodore A; Allen, Joseph G; Minegishi, Taeko; McCarthy, William B; Stewart, James H; Macintosh, David L; McCarthy, John F

2010-05-01

Humans are continuously exposed to low levels of ionizing radiation. Known sources include radon, soil, cosmic rays, medical treatment, food, and building products such as gypsum board and concrete. Little information exists about radiation emissions and associated doses from natural stone finish materials such as granite countertops in homes. To address this knowledge gap, gross radioactivity, gamma ray activity, and dose rate were determined for slabs of granite marketed for use as countertops. Annual effective radiation doses were estimated from measured dose rates and human activity patterns while accounting for the geometry of granite countertops in a model kitchen. Gross radioactivity, gamma activity, and dose rate varied significantly among and within slabs of granite with ranges for median levels at the slab surface of ND to 3000 cpm, ND to 98,000 cpm, and ND to 1.5E-4 mSv/h, respectively. The maximum activity concentrations of the (40)K, (232)Th, and (226)Ra series were 2715, 231, and 450 Bq/kg, respectively. The estimated annual radiation dose from spending 4 h/day in a hypothetical kitchen ranged from 0.005 to 0.18 mSv/a depending on the type of granite. In summary, our results show that the types of granite characterized in this study contain varying levels of radioactive isotopes and that their observed emissions are consistent with those reported in the scientific literature. We also conclude from our analyses that these emissions are likely to be a minor source of external radiation dose when used as countertop material within the home and present a negligible risk to human health.

Monitoring cosmic radiation on aircraft

NASA Astrophysics Data System (ADS)

Bentley, Robert D.; Iles, R. H. A.; Jones, J. B. L.; Hunter, R.; Taylor, G. C.; Thomas, D. J.

2002-03-01

The Earth is constantly bombarded by cosmic radiation that can be either galactic or solar in origin. At aircraft altitudes, the radiation levels are much higher than at sea level and recent European legislation has classified aircrew as radiation workers. University College London is working with Virgin Atlantic Airways on a 3 year project to monitor the levels of cosmic radiation on long-haul flights. The study will determine whether models currently used to predict radiation exposure of aircrew are adequate. It will also try to determine whether solar flare activity can cause significant enhancement to the predicted doses.

University Physics Students' Ideas of Thermal Radiation Expressed in Open Laboratory Activities Using Infrared Cameras

ERIC Educational Resources Information Center

Haglund, Jesper; Melander, Emil; Weiszflog, Matthias; Andersson, Staffan

2017-01-01

Background: University physics students were engaged in open-ended thermodynamics laboratory activities with a focus on understanding a chosen phenomenon or the principle of laboratory apparatus, such as thermal radiation and a heat pump. Students had access to handheld infrared (IR) cameras for their investigations. Purpose: The purpose of the…

Technique for Radiometer and Antenna Array Calibration with a Radiated Noise Diode

NASA Technical Reports Server (NTRS)

Srinivasan, Karthik; Limaye, Ashutosh; Laymon, Charles; Meyer, Paul

2009-01-01

This paper presents a new technique to calibrate a microwave radiometer and antenna array system. This calibration technique uses a radiated noise source in addition to two calibration sources internal to the radiometer. The method accurately calibrates antenna arrays with embedded active devices (such as amplifiers) which are used extensively in active phased array antennas.

Metal-matrix radiation-protective composite materials based on aluminum

NASA Astrophysics Data System (ADS)

Cherdyntsev, V. V.; Gorshenkov, M. V.; Danilov, V. D.; Kaloshkin, S. D.; Gul'bin, V. N.

2013-05-01

A method of mechanical activation providing a homogeneous distribution of reinforcing boron-bearing components and tungsten nanopowder in the matrix is recommended for making an aluminum-based radiation- protective material. Joint mechanical activation and subsequent extrusion are used to produce aluminum- based composites. The structure and the physical, mechanical and tribological characteristics of the composite materials are studied.

Embedded top-coat for reducing the effect out of band radiation in EUV lithography

NASA Astrophysics Data System (ADS)

Du, Ke; Siauw, Meiliana; Valade, David; Jasieniak, Marek; Voelcker, Nico; Trefonas, Peter; Thackeray, Jim; Blakey, Idriss; Whittaker, Andrew

2017-03-01

Out of band (OOB) radiation from the EUV source has significant implications for the performance of EUVL photoresists. Here we introduce a surface-active polymer additive, capable of partitioning to the top of the resist film during casting and annealing, to protect the underlying photoresist from OOB radiation. Copolymers were prepared using reversible addition-fragmentation chain transfer (RAFT) polymerization, and rendered surface active by chain extension with a block of fluoro-monomer. Films were prepared from the EUV resist with added surface-active Embedded Barrier Layer (EBL), and characterized using measurements of contact angles and spectroscopic ellipsometry. Finally, the lithographic performance of the resist containing the EBL was evaluated using Electron Beam Lithography exposure

Remote sensing of solar radiation absorbed and reflected by vegetated land surfaces

NASA Technical Reports Server (NTRS)

Myneni, Ranga B.; Asrar, Ghassem; Tanre, Didier; Choudhury, Bhaskar J.

1992-01-01

1D and 3D radiative-transfer models have been used to investigate the problem of remotely sensed determination of vegetated land surface-absorbed and reflected solar radiation. Calculations were conducted for various illumination conditions to determine surface albedo, soil- and canopy-absorbed photosynthetically active and nonactive radiation, and normalized difference vegetation index. Simple predictive models are developed on the basis of the relationships among these parameters.

The Toll-Like Receptor 2/6 Agonist, FSL-1 Lipopeptide, Therapeutically Mitigates Acute Radiation Syndrome.

PubMed

Kurkjian, Cathryn J; Guo, Hao; Montgomery, Nathan D; Cheng, Ning; Yuan, Hong; Merrill, Joseph R; Sempowski, Gregory D; Brickey, W June; Ting, Jenny P-Y

2017-12-11

Risks of radiation exposure from nuclear incidents and cancer radiotherapy are undeniable realities. These dangers urgently compel the development of agents for ameliorating radiation-induced injuries. Biologic pathways mediated by myeloid differentiation primary response gene 88 (MyD88), the common adaptor for toll-like receptor (TLR) and Interleukin-1 receptor signaling, are critical for radioprotection. Treating with agonists prior to radiation enhances survival by activating TLR signaling, whereas radiomitigating TLR-activating therapeutics given after exposure are less defined. We examine the radiomitigation capability of TLR agonists and identify one that is superior for its efficacy and reduced toxic consequences compared to other tested agonists. We demonstrate that the synthetic TLR2/6 ligand Fibroblast-stimulating lipopeptide (FSL-1) substantially prolongs survival in both male and female mice when administered 24 hours after radiation and shows MyD88-dependent function. FSL-1 treatment results in accelerated hematopoiesis in bone marrow, spleen and periphery, and augments systemic levels of hematopoiesis-stimulating factors. The ability of FSL-1 to stimulate hematopoiesis is critical, as hematopoietic dysfunction results from a range of ionizing radiation doses. The efficacy of a single FSL-1 dose for alleviating radiation injury while protecting against adverse effects reveals a viable radiation countermeasures agent.

Active control of sound radiation from a vibrating rectangular panel by sound sources and vibration inputs - An experimental comparison

NASA Technical Reports Server (NTRS)

Fuller, C. R.; Hansen, C. H.; Snyder, S. D.

1991-01-01

Active control of sound radiation from a rectangular panel by two different methods has been experimentally studied and compared. In the first method a single control force applied directly to the structure is used with a single error microphone located in the radiated acoustic field. Global attenuation of radiated sound was observed to occur by two main mechanisms. For 'on-resonance' excitation, the control force had the effect of increasing the total panel input impedance presented to the nosie source, thus reducing all radiated sound. For 'off-resonance' excitation, the control force tends not significantly to modify the panel total response amplitude but rather to restructure the relative phases of the modes leading to a more complex vibration pattern and a decrease in radiation efficiency. For acoustic control, the second method, the number of acoustic sources required for global reduction was seen to increase with panel modal order. The mechanism in this case was that the acoustic sources tended to create an inverse pressure distribution at the panel surface and thus 'unload' the panel by reducing the panel radiation impedance. In general, control by structural inputs appears more effective than control by acoustic sources for structurally radiated noise.

Co-expression of antioxidant enzymes with expression of p53, DNA repair, and heat shock protein genes in the gamma ray-irradiated hermaphroditic fish Kryptolebias marmoratus larvae.

PubMed

Rhee, Jae-Sung; Kim, Bo-Mi; Kim, Ryeo-Ok; Seo, Jung Soo; Kim, Il-Chan; Lee, Young-Mi; Lee, Jae-Seong

2013-09-15

To investigate effects of gamma ray irradiation in the hermaphroditic fish, Kryptolebias marmoratus larvae, we checked expression of p53, DNA repair, and heat shock protein genes with several antioxidant enzyme activities by quantitative real-time RT-PCR and biochemical methods in response to different doses of gamma radiation. As a result, the level of gamma radiation-induced DNA damage was initiated after 4Gy of radiation, and biochemical and molecular damage became substantial from 8Gy. In particular, several DNA repair mechanism-related genes were significantly modulated in the 6Gy gamma radiation-exposed fish larvae, suggesting that upregulation of such DNA repair genes was closely associated with cell survival after gamma irradiation. The mRNA expression of p53 and most hsps was also significantly upregulated at high doses of gamma radiation related to cellular damage. This finding indicates that gamma radiation can induce oxidative stress with associated antioxidant enzyme activities, and linked to modulation of the expression of DNA repair-related genes as one of the defense mechanisms against radiation damage. This study provides a better understanding of the molecular mode of action of defense mechanisms upon gamma radiation in fish larvae. Copyright © 2013 Elsevier B.V. All rights reserved.

[Reparative Osteogenesis and Angiogenesis in Low Intensity Electromagnetic Radiation of Ultra-High Frequency].

PubMed

Iryanov, Y M; Kiryanov, N A

2015-01-01

Non-drug correction of reparative bone tissue regeneration in different pathological states - one of the most actual problems of modern medicine. Our aim was to conduct morphological analysis of the influence of electromagnetic radiation of ultra-high frequency and low intensity on reparative osteogenesis and angiogenesis in fracture treatment under transosseous osteosynthesis. A controlled nonrandomized study was carried out. In the experiment conducted on rats we modeled tibial fracture with reposition and fixation of the bone fragments both in control and experimental groups. In the animals of the experimental group the fracture zone was exposed to low intensity electromagnetic radiation of ultra-high frequency. Exposure simulation was performed in the control group. The operated bones were examined using radiography, light and electronic microscopy, X-ray electronic probe microanalysis. It has been established that electromagnetic radiation of ultra-high frequency sessions in fracture treatment stimulate secretory activity and degranulation of mast cells, produce microcirculatory bed vascular permeability increase, endotheliocyte migration phenotype expression, provide endovascular endothelial outgrowth formation, activate reparative osteogenesis and angiogenesis while fracture reparation becomes the one of the primary type. The full periosteal, intermediary and intraosteal bone union was defined in 28 days. Among the therapeutic benefits of electromagnetic radiation of ultra-high frequency in fracture treatment we can detect mast cell secretorv activity stimulation and endovascular anziozenesis activation.

A national survey of natural radionuclides in soils and terrestrial radiation exposure in Iran.

PubMed

Kardan, M R; Fathabdi, N; Attarilar, A; Esmaeili-Gheshlaghi, M T; Karimi, M; Najafi, A; Hosseini, S S

2017-11-01

In the past, some efforts have been made for measuring natural radioactivity and evaluating public exposure to natural radiation in certain areas of Iran especially in well-known High Level Natural Radiation Areas (HLNRA) in Ramsar and Mahallat. However, the information on radionuclide concentrations, and, consequently, terrestrial radiation exposure for many other areas are not available. There was therefore a need for a systematic and nation-wide survey. For this purpose, 979 soil samples from 31 provinces were collected. The activity concentrations of 40 K, 226 Ra and 232 Th were measured by HPGe detector. The average activity concentrations for Iran were found to be 457.7 Bq/kg for 40 K, 24.3 Bq/kg for 226 Ra and 25.8 Bq/kg for 232 Th. Results were compared with previous regional or provincial surveys. The population-weighted average outdoor and indoor annual effective dose due to external exposure to terrestrial sources of radiation are 0.06 mSv and 0.33 mSv, respectively. It was shown that there is a significant correlation between the activity concentrations of 232 Th and 40 K in soil. In addition, the results of chi square tests show normal and lognormal distributions cannot be considered for the frequency distributions of activity concentration of 232 Th and 226 Ra while 40 K has a normal distribution. Copyright © 2017 Elsevier Ltd. All rights reserved.

Improved communication, understanding of risk perception and ethics related to ionising radiation.

PubMed

Perko, Tanja; Raskob, Wolfgang; Jourdain, Jean-Rene

2016-06-06

In Europe today, institutions, media and the general public exchange information about ionizing radiation and associated risks. However, communication about ionising radiation with the general public has to be further improved, as has been previously highlighted by international responses to the 2011 accident in Japan. This article reports the main activities and findings in this field from the following three FP7 projects: EAGLE, PREPARE and OPERRA and discussed by a broad spectrum of stakeholders at the conference RICOMET 2015. These projects, among other aims, also investigate how communication about ionising radiation in different fields could be improved and harmonised, how radiological risks are perceived, how to encourage ethical considerations in all fields of nuclear applications and what kind of transdisciplinary research is needed. The projects relate to several domains; the first relates to education, training and communication, the second to nuclear emergency preparedness and response, and the third to research and development in the radiation protection field. Incorporation of stakeholder engagement activities such as the RICOMET conference broadens social and ethical aspects and takes them into account during coordination activities as well as during core scientific and nuclear research and development performed in the projects. These activities offered opportunities for moving closer to a citizen-centred ideal of risk communication in particular and nuclear research and development in general.

The use of an active controlled enclosure to attenuate sound radiation from a heavy radiator

NASA Astrophysics Data System (ADS)

Sun, Yao; Yang, Tiejun; Zhu, Minggang; Pan, Jie

2017-03-01

Active structural acoustical control usually experiences difficulty in the control of heavy sources or sources where direct applications of control forces are not practical. To overcome this difficulty, an active controlled enclosure, which forms a cavity with both flexible and open boundary, is employed. This configuration permits indirect implementation of active control in which the control inputs can be applied to subsidiary structures other than the sources. To determine the control effectiveness of the configuration, the vibro-acoustic behavior of the system, which consists of a top plate with an open, a sound cavity and a source panel, is investigated in this paper. A complete mathematical model of the system is formulated involving modified Fourier series formulations and the governing equations are solved using the Rayleigh-Ritz method. The coupling mechanisms of a partly opened cavity and a plate are analysed in terms of modal responses and directivity patterns. Furthermore, to attenuate sound power radiated from both the top panel and the open, two strategies are studied: minimizing the total radiated power and the cancellation of volume velocity. Moreover, three control configurations are compared, using a point force on the control panel (structural control), using a sound source in the cavity (acoustical control) and applying hybrid structural-acoustical control. In addition, the effects of boundary condition of the control panel on the sound radiation and control performance are discussed.

Absorbed photosynthetically active radiation of steppe vegetation and sun-view geometry effects on APAR estimates

NASA Technical Reports Server (NTRS)

Walter-Shea, E. A.; Blad, B. L.; Mesarch, M. A.; Hays, C. J.; Deering, D. W.; Eck, T. F.

1992-01-01

Instantaneous fractions of absorbed photosynthetically active radiation (APAR) were measured at the Streletskaya Steppe Reserve in conjunction with canopy bidirectional-reflected radiation measured at solar zenith angles ranging between 37 and 74 deg during the Kursk experiment (KUREX-91). APAR values were higher for KUREX-91 than those for the first ISLSCP field experiment (FIFE-89) and the amount of APAR of a canopy was a function of solar zenith angle, decreasing as solar zenith angle increased at the resrve. Differences in absorption are attributed to leaf area index (LAI) and leaf angle distribution and subsequently transmitted radiation interactions. LAIs were considerably higher at the reserve than those at the FIFE site. Leaf angle distributions of the reserve approach a uniform distribution while distributions at the FIFE site more closely approximate erectophile distributions. Reflected photosynthetically active radiation (PAR) components at KUREX-91 and FIFE-89 were similar in magnitude and in their response to solar zenith angle. Transmitted PAR increased with increasing solar zenith angle at KUREX-91 and decreased with increasing solar zenith angle at FIFE-89. Transmitted PAR at FIFE-89 was considerably larger than those at KUREX-91.

Observations of lightning processes using VHF radio interferometry

NASA Technical Reports Server (NTRS)

Rhodes, C. T.; Shao, X. M.; Krehbiel, P. R.; Thomas, R.

1991-01-01

A single station, multiple baseline radio interferometer was used to locate the direction of VHF radiation from lightning discharges with microsec time resolution. Radiation source directions and electric field waveforms were analyzed for various types of breakdown events. These include initial breakdown and K type events of in-cloud activity, and the leaders of initial and subsequent strokes to ground and activity during and following return strokes. Radiation during the initial breakdown of a flash and in the early stages of initial leaders to ground is found to be similar. In both instances, the activity consists of localized bursts of radiation that are intense and slow moving. Motion within a given burst is unresolved by the interferometer. Radiation from in-cloud K type events is essentially the same as that from dart leaders; in both cases it is produced at the leading edge of a fast moving streamer that propagates along a well defined, often extensive path. K type events are sometimes terminated by fast field changes that are similar to the return stroke initiated by dart leaders; such K type events are the in-cloud analog of the dart leader return stroke process.

Radiation Monitoring Equipment Dosimeter Experiment

NASA Technical Reports Server (NTRS)

Hardy, Kenneth A.; Golightly, Michael J.; Quam, William

1992-01-01

Spacecraft crews risk exposure to relatively high levels of ionizing radiation. This radiation may come from charged particles trapped in the Earth's magnetic fields, charged particles released by solar flare activity, galactic cosmic radiation, energetic photons and neutrons generated by interaction of these primary radiations with spacecraft and crew, and man-made sources (e.g., nuclear power generators). As missions are directed to higher radiation level orbits, viz., higher altitudes and inclinations, longer durations, and increased flight frequency, radiation exposure could well become a major factor for crew stay time and career lengths. To more accurately define the radiological exposure and risk to the crew, real-time radiation monitoring instrumentation, which is capable of identifying and measuring the various radiation components, must be flown. This presentation describes a radiation dosimeter instrument which was successfully flown on the Space Shuttle, the RME-3.

Interactions between TGF-β1, canonical WNT/β-catenin pathway and PPAR γ in radiation-induced fibrosis

PubMed Central

Vallée, Alexandre; Lecarpentier, Yves; Guillevin, Rémy; Vallée, Jean-Noël

2017-01-01

Radiation therapy induces DNA damage and inflammation leading to fibrosis. Fibrosis can occur 4 to 12 months after radiation therapy. This process worsens with time and years. Radiation-induced fibrosis is characterized by fibroblasts proliferation, myofibroblast differentiation, and synthesis of collagen, proteoglycans and extracellular matrix. Myofibroblasts are non-muscle cells that can contract and relax. Myofibroblasts evolve towards irreversible retraction during fibrosis process. In this review, we discussed the interplays between transforming growth factor-β1 (TGF-β1), canonical WNT/β-catenin pathway and peroxisome proliferator-activated receptor gamma (PPAR γ) in regulating the molecular mechanisms underlying the radiation-induced fibrosis, and the potential role of PPAR γ agonists. Overexpression of TGF-β and canonical WNT/β-catenin pathway stimulate fibroblasts accumulation and myofibroblast differentiation whereas PPAR γ expression decreases due to the opposite interplay of canonical WNT/β-catenin pathway. Both TGF-β1 and canonical WNT/β-catenin pathway stimulate each other through the Smad pathway and non-Smad pathways such as phosphatidylinositol 3-kinase/serine/threonine kinase (PI3K/Akt) signaling. WNT/β-catenin pathway and PPAR γ interact in an opposite manner. PPAR γ agonists decrease β-catenin levels through activation of inhibitors of the WNT pathway such as Smad7, glycogen synthase kinase-3 (GSK-3 β) and dickkopf-related protein 1 (DKK1). PPAR γ agonists also stimulate phosphatase and tensin homolog (PTEN) expression, which decreases both TGF-β1 and PI3K/Akt pathways. PPAR γ agonists by activating Smad7 decrease Smads pathway and then TGF-β signaling leading to decrease radiation-induced fibrosis. TGF-β1 and canonical WNT/β-catenin pathway promote radiation-induced fibrosis whereas PPAR γ agonists can prevent radiation-induced fibrosis. PMID:29163854

Haemopoietic cell renewal in radiation fields

NASA Astrophysics Data System (ADS)

Fliedner, T. M.; Nothdurft, W.; Tibken, B.; Hofer, E.; Weiss, M.; Kindler, H.

1994-10-01

Space flight activities are inevitably associated with a chronic exposure of astronauts to a complex mixture of ionising radiation. Although no acute radiation consequences are to be expected as a rule, the possibility of Solar Particle Events (SPE) associated with relatively high doses of radiation (1 or more Gray) cannot be excluded. It is the responsibility of physicians in charge of the health of astronauts to evaluate before, during and after space flight activities the functional status of haemopoietic cell renewal. Chronic low level exposure of dogs indicate that daily gamma-exposure doses below about 2 cGy are tolerated for several years as far as blood cell concentrations are concerned. However, the stem cell pool may be severely affected. The maintenance of sufficient blood cell counts is possible only through increased cell production to compensate for the radiation inflicted excess cell loss. This behaviour of haemopoietic cell renewal during chronic low level exposure can be simulated by bioengineering models of granulocytopoiesis. It is possible to define a ``turbulence region'' for cell loss rates, below which an prolonged adaptation to increased radiation fields can be expected to be tolerated. On the basis of these experimental results, it is recommended to develop new biological indicators to monitor haemopoietic cell renewal at the level of the stem cell pool using blood stem cells in addition to the determination of cytokine concentrations in the serum (and other novel approaches). To prepare for unexpected haemopoietic effects during prolonged space missions, research should be increased to modify the radiation sensitivity of haemopoietic stem cells (for instance by the application of certain regulatory molecules). In addition, a ``blood stem cell bank'' might be established for the autologous storage of stem cells and for use in space activities keeping them in a radiation protected container.

Novel Regenerative Peptide TP508 Mitigates Radiation-Induced Gastrointestinal Damage By Activating Stem Cells and Preserving Crypt Integrity

PubMed Central

Kantara, Carla; Moya, Stephanie M.; Houchen, Courtney W.; Umar, Shahid; Ullrich, Robert L.; Singh, Pomila; Carney, Darrell H.

2015-01-01

In recent years, increasing threats of radiation exposure and nuclear disasters have become a significant concern for the United States and countries worldwide. Exposure to high doses of radiation triggers a number of potentially lethal effects. Among the most severe is the gastrointestinal (GI) toxicity syndrome caused by the destruction of the intestinal barrier, resulting in bacterial translocation, systemic bacteremia, sepsis and death. The lack of effective radioprotective agents capable of mitigating radiation-induced damage has prompted a search for novel countermeasures that can mitigate the effects of radiation post-exposure, accelerate tissue repair in radiation-exposed individuals, and prevent mortality. We report that a single injection of regenerative peptide TP508 (rusalatide acetate, Chrysalin®) 24h after lethal radiation exposure (9Gy, LD100/15) appears to significantly increase survival and delay mortality by mitigating radiation-induced intestinal and colonic toxicity. TP508 treatment post-exposure prevents the disintegration of gastrointestinal crypts, stimulates the expression of adherens junction protein E-cadherin, activates crypt cell proliferation, and decreases apoptosis. TP508 post-exposure treatment also up-regulates the expression of DCLK1 and LGR5 markers of stem cells that have been shown to be responsible for maintaining and regenerating intestinal crypts. Thus, TP508 appears to mitigate the effects of GI toxicity by activating radioresistant stem cells and increasing the stemness potential of crypts to maintain and restore intestinal integrity. These results suggest that TP508 may be an effective emergency nuclear countermeasure that could be delivered within 24h post-exposure to increase survival and delay mortality, giving victims time to reach clinical sites for advanced medical treatment. PMID:26280221

The Mars Dust Cycle: Investigating the Effects of Radiatively Active Water Ice Clouds on Surface Stresses and Dust Lifting Potential with the NASA Ames Mars General Circulation Model

NASA Technical Reports Server (NTRS)

Kahre, Melinda A.; Hollingsworth, Jeffery

2012-01-01

The dust cycle is a critically important component of Mars' current climate system. Dust is present in the atmosphere of Mars year-round but the dust loading varies with season in a generally repeatable manner. Dust has a significant influence on the thermal structure of the atmosphere and thus greatly affects atmospheric circulation. The dust cycle is the most difficult of the three climate cycles (CO2, water, and dust) to model realistically with general circulation models. Until recently, numerical modeling investigations of the dust cycle have typically not included the effects of couplings to the water cycle through cloud formation. In the Martian atmosphere, dust particles likely provide the seed nuclei for heterogeneous nucleation of water ice clouds. As ice coats atmospheric dust grains, the newly formed cloud particles exhibit different physical and radiative characteristics. Thus, the coupling between the dust and water cycles likely affects the distributions of dust, water vapor and water ice, and thus atmospheric heating and cooling and the resulting circulations. We use the NASA Ames Mars GCM to investigate the effects of radiatively active water ice clouds on surface stress and the potential for dust lifting. The model includes a state-of-the-art water ice cloud microphysics package and a radiative transfer scheme that accounts for the radiative effects of CO2 gas, dust, and water ice clouds. We focus on simulations that are radiatively forced by a prescribed dust map, and we compare simulations that do and do not include radiatively active clouds. Preliminary results suggest that the magnitude and spatial patterns of surface stress (and thus dust lifting potential) are substantial influenced by the radiative effects of water ice clouds.

Modeled Microgravity Inhibits Apoptosis in Peripheral Blood Lymphocytes

NASA Technical Reports Server (NTRS)

Risin, Diana; Pellis, Neal R.

2000-01-01

Microgravity interferes with numerous lymphocyte functions (expression of cell surface molecules, locomotion, polyclonal and antigen-specific activation, and the protein kinase C activity in signal transduction). The latter suggests that gravity may also affect programmed cell death (PCD) in lymphocyte populations. To test this hypothesis, we investigated spontaneous, activation- and radiation-induced PCD in peripheral blood mononuclear cells (PBMC) exposed to modeled microgravity using a rotating cell culture system. The results showed significant inhibition of radiation- and activation-induced apoptosis in modeled microgravity and provide insights into the potential mechanisms of this phenomenon.

Modeled microgravity inhibits apoptosis in peripheral blood lymphocytes

NASA Technical Reports Server (NTRS)

Risin, D.; Pellis, N. R.; McIntire, L. V. (Principal Investigator)

2001-01-01

Microgravity interferes with numerous lymphocyte functions (expression of cell surface molecules, locomotion, polyclonal and antigen-specific activation, and the protein kinase C activity in signal transduction). The latter suggests that gravity may also affect programmed cell death (PCD) in lymphocyte populations. To test this hypothesis, we investigated spontaneous, activation- and radiation-induced PCD in peripheral blood mononuclear cells exposed to modeled microgravity (MMG) using a rotating cell culture system. The results showed significant inhibition of radiation- and activation-induced apoptosis in MMG and provide insights into the potential mechanisms of this phenomenon.

Gamma-irradiated bacterial preparation having anti-tumor activity

DOEpatents

Vass, Arpad A.; Tyndall, Richard L.; Terzaghi-Howe, Peggy

1999-01-01

A bacterial preparation from Pseudomonas species isolated #15 ATCC 55638 that has been exposed to gamma radiation exhibits cytotoxicity that is specific for neoplastic carcinoma cells. A method for obtaining a bacterial preparation having antitumor activity consists of suspending a bacterial isolate in media and exposing the suspension to gamma radiation. A bacterial preparation of an aged culture of an amoeba-associated bacteria exhibits anti-reverse transcriptase activity. A method for obtaining a bacterial preparation having anti-reverse transcriptase activity from an amoeba-associated bacterial isolate grown to stationary phase is disclosed.

Antioxidant power, lipid oxidation, color, and viability of Listeria monocytogenes in beef bologna treated with gamma radiation and containing various levels of glucose.

PubMed

Sommers, Christopher H; Fan, Xuetong

2002-11-01

Ionizing radiation can be used to pasteurize ready-to-eat (RTE) meat products. Thermal processing of RTE meats that contain dextrose results in the production of antioxidants that may interfere with ionizing radiation pasteurization of RTE meat products. Beef bologna was manufactured with dextrose concentrations of 0, 2, 4, 6, and 8%. Antioxidant activity, as measured by the Ferric Reducing Antioxidant Power assay, increased with dextrose concentration but was unaffected by ionizing radiation. Lipid oxidation increased significantly in irradiated bologna (4 kGy) that contained dextrose. Hunter color analysis indicated that the addition of dextrose reduced the ionizing radiation-induced loss of redness (a-value) but promoted the loss of brightness (L-value). The radiation resistance, D10-value, of Listeria monocytogenes that was surface-inoculated onto bologna slices was not affected by dextrose concentration. L. monocytogenes strains isolated from RTE meats after listeriosis outbreaks were utilized. Increased antioxidant activity generated by thermal processing of dextrose in fine emulsion sausages does not present a barrier to radiation pasteurization of RTE meats. However, a high dextrose concentration in combination with gamma irradiation increases lipid oxidation significantly.

Foundation, excavation and radiation shielding concepts for a 16-m large lunar telescope

NASA Technical Reports Server (NTRS)

Chua, Koon M.; Johnson, Stewart W.

1991-01-01

NASA is considering a 16-m diameter optical telescope on the moon as a part of the Space Exploration Initiative. Fundamental concepts of engineering activities on the moon and how they can be applied to the establishment of a 16-m large lunar telescope (LLT) are discussed. These fundamental concepts include the engineering response of lunar soils and how they affect construction activities, namely, drilling, blasting, ripping, digging and compaction. A mirror support structure and foundation design concept is proposed. The foundation considered is a multiple contact points spud-can type footing. It does not appear that a deep foundation or the presence of bedrock is required to achieve the telescope foundation stiffness. The LLT system will include a regolith covered housing, the size of a small room, which will contain sensitive electronic equipment including charge coupled devices which need protection from cosmic radiation effects. A brief discussion is made on radiation, radiation transport and radiation effects on electronics and on humans. Radiation protection techniques and the different emplacement schemes for the LLT instrument housing for radiation protection are suggested. A structural concept of an early lunar based telescope is also presented.

Illumination system having a plurality of movable sources

DOEpatents

Sweatt, William C.; Kubiak, Glenn D.

2002-01-01

An illumination system includes several discharge sources that are multiplexed together to reduce the amount of debris generated. The system includes: (a) a first electromagnetic radiation source array that includes a plurality of first activatable radiation source elements that are positioned on a first movable carriage; (b) a second electromagnetic radiation source array that includes a plurality of second activatable radiation source elements that are positioned on a second movable carriage; (c) means for directing electromagnetic radiation from the first electromagnetic radiation source array and electromagnetic radiation from the second electromagnetic radiation source array toward a common optical path; (d) means for synchronizing (i) the movements of the first movable carriage and of the second movable carriage and (ii) the activation of the first electromagnetic radiation source array and of the second electromagnetic radiation source array to provide an essentially continuous illumination of electromagnetic radiation along the common optical path.

A boundary element approach to optimization of active noise control sources on three-dimensional structures

NASA Technical Reports Server (NTRS)

Cunefare, K. A.; Koopmann, G. H.

1991-01-01

This paper presents the theoretical development of an approach to active noise control (ANC) applicable to three-dimensional radiators. The active noise control technique, termed ANC Optimization Analysis, is based on minimizing the total radiated power by adding secondary acoustic sources on the primary noise source. ANC Optimization Analysis determines the optimum magnitude and phase at which to drive the secondary control sources in order to achieve the best possible reduction in the total radiated power from the noise source/control source combination. For example, ANC Optimization Analysis predicts a 20 dB reduction in the total power radiated from a sphere of radius at a dimensionless wavenumber ka of 0.125, for a single control source representing 2.5 percent of the total area of the sphere. ANC Optimization Analysis is based on a boundary element formulation of the Helmholtz Integral Equation, and thus, the optimization analysis applies to a single frequency, while multiple frequencies can be treated through repeated analyses.

Nrf2 Activation Protects against Solar-Simulated Ultraviolet Radiation in Mice and Humans.

PubMed

Knatko, Elena V; Ibbotson, Sally H; Zhang, Ying; Higgins, Maureen; Fahey, Jed W; Talalay, Paul; Dawe, Robert S; Ferguson, James; Huang, Jeffrey T-J; Clarke, Rosemary; Zheng, Suqing; Saito, Akira; Kalra, Sukirti; Benedict, Andrea L; Honda, Tadashi; Proby, Charlotte M; Dinkova-Kostova, Albena T

2015-06-01

The transcription factor Nrf2 determines the ability to adapt and survive under conditions of electrophilic, oxidative, and inflammatory stress by regulating the expression of elaborate networks comprising nearly 500 genes encoding proteins with versatile cytoprotective functions. In mice, disruption of Nrf2 increases susceptibility to carcinogens and accelerates disease pathogenesis. Paradoxically, Nrf2 is upregulated in established human tumors, but whether this upregulation drives carcinogenesis is not known. Here we show that the incidence, multiplicity, and burden of solar-simulated UV radiation-mediated cutaneous tumors that form in SKH-1 hairless mice in which Nrf2 is genetically constitutively activated are lower than those that arise in their wild-type counterparts. Pharmacologic Nrf2 activation by topical biweekly applications of small (40 nmol) quantities of the potent bis(cyano enone) inducer TBE-31 has a similar protective effect against solar-simulated UV radiation in animals receiving long-term treatment with the immunosuppressive agent azathioprine. Genetic or pharmacologic Nrf2 activation lowers the expression of the pro-inflammatory factors IL6 and IL1β, and COX2 after acute exposure of mice to UV radiation. In healthy human subjects, topical applications of extracts delivering the Nrf2 activator sulforaphane reduced the degree of solar-simulated UV radiation-induced skin erythema, a quantifiable surrogate endpoint for cutaneous damage and skin cancer risk. Collectively, these data show that Nrf2 is not a driver for tumorigenesis even upon exposure to a very potent and complete carcinogen and strongly suggest that the frequent activation of Nrf2 in established human tumors is a marker of metabolic adaptation. ©2015 American Association for Cancer Research.

Nrf2 activation protects against solar-simulated ultraviolet radiation in mice and humans

PubMed Central

Knatko, Elena V.; Ibbotson, Sally H.; Zhang, Ying; Higgins, Maureen; Fahey, Jed W.; Talalay, Paul; Dawe, Robert S.; Ferguson, James; Huang, Jeffrey T.-J.; Clarke, Rosemary; Zheng, Suqing; Saito, Akira; Kalra, Sukirti; Benedict, Andrea L.; Honda, Tadashi; Proby, Charlotte M.; Dinkova-Kostova, Albena T.

2015-01-01

The transcription factor Nrf2 determines the ability to adapt and survive under conditions of electrophilic, oxidative and inflammatory stress by regulating the expression of elaborate networks comprising nearly 500 genes encoding proteins with versatile cytoprotective functions. In mice, disruption of Nrf2 increases susceptibility to carcinogens and accelerates disease pathogenesis. Paradoxically, Nrf2 is upregulated in established human tumors, but whether this upregulation drives carcinogenesis is not known. Here we show that the incidence, multiplicity and burden of solar-simulated UV radiation-mediated cutaneous tumors that form in SKH-1 hairless mice in which Nrf2 is genetically constitutively activated, are lower than those that arise in their wild-type counterparts. Pharmacological Nrf2 activation by topical bi-weekly applications of small (40 nmol) quantities of the potent bis(cyano enone) inducer TBE-31 has a similar protective effect against solar-simulated UV radiation in animals receiving long-term treatment with the immunosuppressive agent azathioprine. Genetic or pharmacological Nrf2 activation lowers the expression of the pro-inflammatory factors interleukin (IL)-6 and IL-1β, and cyclooxygenase (COX)-2 after acute exposure of mice to UV radiation. In healthy human subjects, topical applications of extracts delivering the Nrf2 activator sulforaphane, reduced the degree of solar-simulated UV radiation-induced skin erythema, a quantifiable surrogate end-point for cutaneous damage and skin cancer risk. Collectively, these data show that Nrf2 is not a driver for tumorigenesis even upon exposure to a very potent and complete carcinogen, and strongly suggest that the frequent activation of Nrf2 in established human tumors is a marker of metabolic adaptation. PMID:25804610

Taurine Protects Mouse Spermatocytes from Ionizing Radiation-Induced Damage Through Activation of Nrf2/HO-1 Signaling.

PubMed

Yang, Wenjun; Huang, Jinfeng; Xiao, Bang; Liu, Yan; Zhu, Yiqing; Wang, Fang; Sun, Shuhan

2017-01-01

The increasing prevalence of ionizing radiation exposure has inevitably raised public concern over the potential detrimental effects of ionizing radiation on male reproductive system function. The detection of drug candidates to prevent reproductive system from damage caused by ionizing radiation is urgent. We aimed to investigate the protective role of taurine on the injury of mouse spermatocyte-derived cells (GC-2) subjected to ionizing radiation. mouse spermatocytes (GC-2 cells) were exposed to ionizing radiation with or without treatment of Taurine. The effect of ionizing radiation and Taurine treatment on GC-2 cells were evaluated by cell viability assay (CCK8), cell cycle and apoptosis. The relative protein abundance change was determined by Western blotting. The siRNA was used to explore whether Nrf2 signaling was involved in the cytoprotection of Taurine. Taurine significantly inhibited the decrease of cell viability, percentage of apoptotic cells and cell cycle arrest induced by ionizing radiation. Western blot analysis showed that taurine significantly limited the ionizing radiation-induced down-regulation of CyclinB1 and CDK1, and suppressed activation of Fas/FasL system pathway. In addition, taurine treatment significantly increased the expression of Nrf2 and HO-1 in GC-2 cells exposed to ionizing radiation, two components in antioxidant pathway. The above cytoprotection of Taurine was blocked by siNrf2. Our results demonstrate that taurine has the potential to effectively protect GC-2 cells from ionizing radiation- triggered damage via upregulation of Nrf2/HO-1 signaling. © 2017 The Author(s). Published by S. Karger AG, Basel.

Relationships between radiation, clouds, and convection during DYNAMO

NASA Astrophysics Data System (ADS)

Ciesielski, Paul E.; Johnson, Richard H.; Jiang, Xianan; Zhang, Yunyan; Xie, Shaocheng

2017-03-01

The relationships between radiation, clouds, and convection on an intraseasonal time scale are examined with data taken during the Dynamics of the Madden-Julian Oscillation (MJO) field campaign. Specifically, column-net, as well as vertical profiles of radiative heating rates, computed over Gan Island in the central Indian Ocean (IO) are used along with an objective analysis of large-scale fields to examine three MJO events that occurred during the 3 month period (October to December 2011) over this region. Longwave (LW) and shortwave radiative heating rates exhibit tilted structures, reflecting radiative effects associated with the prevalence of shallow cumulus during the dry, suppressed MJO phase followed by increasing deep convection leading into the active phase. As the convection builds going into the MJO active phase, there are increasingly top-heavy anomalous radiative heating rates while the column-net radiative cooling rate progressively decreases. Temporal fluctuations in the cloud radiative forcing, being quite sensitive to changes in high cloudiness, are dominated by LW effects with an intraseasonal variation of 0.4-0.6 K/d. While both the water vapor and cloud fields are inextricably linked, it appears that the tilted radiative structures are more related to water vapor effects. The intraseasonal variation of column-net radiative heating enhances the convective signal in the mean by 20% with a minimum in this enhancement 10 days prior to peak MJO rainfall and maximum 7 days after. This suggests that as MJO convective envelope weakens over the central IO, cloud-radiative feedbacks help maintain the mature MJO as it moves eastward.

Relationships between radiation, clouds, and convection during DYNAMO.

PubMed

Ciesielski, Paul E; Johnson, Richard H; Jiang, Xianan; Zhang, Yunyan; Xie, Shaocheng

2017-03-16

The relationships between radiation, clouds, and convection on an intraseasonal time scale are examined with data taken during the Dynamics of the Madden-Julian Oscillation (MJO) field campaign. Specifically, column-net, as well as vertical profiles of radiative heating rates, computed over Gan Island in the central Indian Ocean (IO) are used along with an objective analysis of large-scale fields to examine three MJO events that occurred during the 3 month period (October to December 2011) over this region. Longwave (LW) and shortwave radiative heating rates exhibit tilted structures, reflecting radiative effects associated with the prevalence of shallow cumulus during the dry, suppressed MJO phase followed by increasing deep convection leading into the active phase. As the convection builds going into the MJO active phase, there are increasingly top-heavy anomalous radiative heating rates while the column-net radiative cooling rate < Q r > progressively decreases. Temporal fluctuations in the cloud radiative forcing, being quite sensitive to changes in high cloudiness, are dominated by LW effects with an intraseasonal variation of ~0.4-0.6 K/d. While both the water vapor and cloud fields are inextricably linked, it appears that the tilted radiative structures are more related to water vapor effects. The intraseasonal variation of column-net radiative heating < Q r > enhances the convective signal in the mean by ~20% with a minimum in this enhancement ~10 days prior to peak MJO rainfall and maximum ~7 days after. This suggests that as MJO convective envelope weakens over the central IO, cloud-radiative feedbacks help maintain the mature MJO as it moves eastward.

Relationships between radiation, clouds, and convection during DYNAMO

PubMed Central

Ciesielski, Paul E.; Johnson, Richard H.; Jiang, Xianan; Zhang, Yunyan; Xie, Shaocheng

2017-01-01

The relationships between radiation, clouds, and convection on an intraseasonal time scale are examined with data taken during the Dynamics of the Madden-Julian Oscillation (MJO) field campaign. Specifically, column-net, as well as vertical profiles of radiative heating rates, computed over Gan Island in the central Indian Ocean (IO) are used along with an objective analysis of large-scale fields to examine three MJO events that occurred during the 3 month period (October to December 2011) over this region. Longwave (LW) and shortwave radiative heating rates exhibit tilted structures, reflecting radiative effects associated with the prevalence of shallow cumulus during the dry, suppressed MJO phase followed by increasing deep convection leading into the active phase. As the convection builds going into the MJO active phase, there are increasingly top-heavy anomalous radiative heating rates while the column-net radiative cooling rate progressively decreases. Temporal fluctuations in the cloud radiative forcing, being quite sensitive to changes in high cloudiness, are dominated by LW effects with an intraseasonal variation of ~0.4–0.6 K/d. While both the water vapor and cloud fields are inextricably linked, it appears that the tilted radiative structures are more related to water vapor effects. The intraseasonal variation of column-net radiative heating enhances the convective signal in the mean by ~20% with a minimum in this enhancement ~10 days prior to peak MJO rainfall and maximum ~7 days after. This suggests that as MJO convective envelope weakens over the central IO, cloud-radiative feedbacks help maintain the mature MJO as it moves eastward. PMID:29082119

Impact of preschool environment upon children's physical activity and sun exposure.

PubMed

Boldemann, Cecilia; Blennow, Margareta; Dal, Henrik; Mårtensson, Fredrika; Raustorp, Anders; Yuen, Katarina; Wester, Ulf

2006-04-01

The physical qualities of outdoor environments are important to trigger healthy behavior in children. We studied the impact of outdoor environments upon spontaneous physical activity and exposure to ultraviolet (UV) radiation in 4- to 6-year-old children at 11 preschools in Stockholm county. In May-June 2004, pedometry and measurement of UV radiation were carried out on 197 children from 11 preschools in Stockholm county. Outdoor environments differed regarding vegetation, topography, space, and education. Ambient global UV radiation data were collected, free sky, and ground surface assessed. Arrival, in- and outdoor stay, and departure were recorded. For analysis, linear mixed model analysis was applied. In environments with trees, shrubbery, and broken ground, the mean step count/min was 21.5, and mean exposure to UV radiation as fraction of available UV during play outdoors 14.6%. In delimited environments with little vegetation, the mean step count/min was 17.7 and mean exposure fraction to UV radiation 24.3% (P < 0.001, crude). Step/min range was 8.9-30.0 (girls) and 8.8-37.2 (boys), UV radiation exposure range 4-60% (no difference between genders). Spacious preschool environments with trees, shrubbery, and broken ground trigger physical activity and yield sun protection in outdoor play. As many children attend preschool, access to such environments is recommended in community architecture.

Targeting Phosphatidylinositide3-Kinase/Akt pathway by BKM120 for radiosensitization in hepatocellular carcinoma

PubMed Central

Liu, Wei-Lin; Gao, Ming; Tzen, Kai-Yuan; Tsai, Chiao-Ling; Hsu, Feng-Ming; Cheng, Ann-Lii; Cheng, Jason Chia-Hsien

2014-01-01

Tumor control of hepatocellular carcinoma by radiotherapy remains unsatisfactory. The phosphatidylinositol 3-kinase (PI3K)/Akt pathway plays a critical role in inhibiting cancer cell death. Elevated PI3K/Akt activity is associated with increased cellular resistance to irradiation. Our aim was to determine whether the inhibition of PI3K/Akt activity by a PI3K inhibitor, BKM120, contributes to the increased sensitivity of liver cancer cells to irradiation. The hepatocellular carcinoma cell lines (Huh7 and BNL) were used to evaluate the in vitro synergism between BKM120 and irradiation. Balb/c mice bearing ectopic BNL xenografts were treated with BKM120 and/or radiotherapy to assess the in vivo response. BKM120 increased cell killing by radiation, increased the expression of apoptotic markers, and suppressed the repair of radiation-induced DNA double-strand breaks. BKM120 pretreatment inhibited radiation-induced Akt phosphorylation and enhanced the tumor-suppressive effect and radiation-induced tumor cell apoptosis in ectopic xenografts. Inhibition of mTOR phosphorylation by rapamycin enhanced the radiosensitivity of BKM120-treated hepatocellular carcinoma cells. The synergism between BKM120 and irradiation likely inhibits the activation of Akt by radiation, leading to increased cell apoptosis and suppression of DNA-double-strand breaks repair in hepatocellular carcinoma cells. These data suggest that the BKM120/radiation combination may be a strategy worthy of clinical trials. PMID:25004403

Prior irradiation results in elevated programmed cell death protein 1 (PD-1) in T cells.

PubMed

Li, Deguan; Chen, Renxiang; Wang, Yi-Wen; Fornace, Albert J; Li, Heng-Hong

2018-05-01

In this study we addressed the question whether radiation-induced adverse effects on T cell activation are associated with alterations of T cell checkpoint receptors. Expression levels of checkpoint receptors on T cell subpopulations were analyzed at multiple post-radiation time points ranging from one to four weeks in mice receiving a single fraction of 1 or 4 Gy of γ-ray. T cell activation associated metabolic changes were assessed. Our results showed that prior irradiation resulted in significant elevated expression of programmed cell death protein 1 (PD-1) in both CD4+ and CD8+ populations, at all three post-radiation time points. T cells with elevated PD-1 mostly were either central memory or naïve cells. In addition, the feedback induction of PD-1 expression in activated T cells declined after radiation. Taken together, the elevated PD-1 level observed at weeks after radiation exposure is connected to T cell dysfunction. Recent preclinical and clinical studies have showed that a combination of radiotherapy and T cell checkpoint blockade immunotherapy including targeting the programmed death-ligand 1 (PD-L1)/PD-1 axis may potentiate the antitumor response. Understanding the dynamic changes in PD-1 levels in T cells after radiation should help in the development of a more effective therapeutic strategy.

Mobile phone electromagnetic radiation activates MAPK signaling and regulates viability in Drosophila.

PubMed

Lee, Kyu-Sun; Choi, Jong-Soon; Hong, Sae-Yong; Son, Tae-Ho; Yu, Kweon

2008-07-01

Mobile phones are widely used in the modern world. However, biological effects of electromagnetic radiation produced by mobile phones are largely unknown. In this report, we show biological effects of the mobile phone 835 MHz electromagnetic field (EMF) in the Drosophila model system. When flies were exposed to the specific absorption rate (SAR) 1.6 W/kg, which is the proposed exposure limit by the American National Standards Institute (ANSI), more than 90% of the flies were viable even after the 30 h exposure. However, in the SAR 4.0 W/kg strong EMF exposure, viability dropped from the 12 h exposure. These EMF exposures triggered stress response and increased the production of reactive oxygen species. The EMF exposures also activated extracellular signal regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) signaling, but not p38 kinase signaling. Interestingly, SAR 1.6 W/kg activated mainly ERK signaling and expression of an anti-apoptotic gene, whereas SAR 4.0 W/kg strongly activated JNK signaling and expression of apoptotic genes. In addition, SAR 4.0 W/kg amplified the number of apoptotic cells in the fly brain. These findings demonstrate that the exposure limit on electromagnetic radiation proposed by ANSI triggered ERK-survival signaling but the strong electromagnetic radiation activated JNK-apoptotic signaling in Drosophila.

Piezoelectric wafer active sensors under gamma radiation exposure toward applications for structural health monitoring of nuclear dry cask storage systems

NASA Astrophysics Data System (ADS)

Faisal Haider, Mohammad; Mei, Hanfei; Lin, Bin; Yu, Lingyu; Giurgiutiu, Victor; Lam, Poh-Sang; Verst, Christopher

2018-03-01

Structural health monitoring (SHM) is in urgent need and must be integrated into the nuclear-spent fuel storage systems to guarantee the safe operation. The dry cask storage system (DCSS) is such storage facility, which is licensed for temporary storage for nuclear-spent fuel at the independent spent fuel storage installations (ISFSIs) for certain predetermined period of time. Gamma radiation is one of the major radiation sources near DCSS. Therefore, a detailed experimental investigation was completed on the gamma radiation endurance of piezoelectric wafer active sensors (PWAS) transducers for SHM applications to the DCSS system. The irradiation test was done in a Co-60 gamma irradiator. Lead Zirconate Titanate (PZT) and Gallium Orthophosphate (GaPO4) PWAS transducers were exposed to 40.7 kGy gamma radiation. Total radiation dose was achieved in two different radiation dose rates: (a) slower radiation rate at 0.1 kGy/hr for 20 hours (b) accelerated radiation rate at 1.233 kGy/hr for 32 hours. The total cumulative radiation dose of 40.7 kGy is equivalent to 45 years of operation in DCSS system. Electro-mechanical impedance and admittance (EMIA) signatures and electrical capacitance were measured to evaluate the PWAS performance after each gamma radiation exposure. The change in resonance frequency of PZT-PWAS transducer for both in-plane and thickness mode was observed. The GaPO4-PWAS EMIA spectra do not show a significant shift in resonance frequency after gamma irradiation exposure. Radiation endurance of new high-temperature HPZ-HiT PWAS transducer was also evaluated. The HPZ-HiT transducers were exposed to gamma radiation at 1.233 kGy/hr for 160 hours with 80 hours interval. Therefore, the total accumulated gamma radiation dose is 184 kGy. No significant change in impedance spectra was observed due to gamma radiation exposure.

Summary of radiation dosimetry results on U.S. and Soviet manned spacecraft.

PubMed

Benton, E V

1986-01-01

Measurements of the radiation environment aboard U.S. and Soviet manned spacecraft are reviewed and summarized. Data obtained mostly from passive and some active radiation detectors now exist for the case of low Earth-orbit missions. Major uncertainties still exist for space exposure in high altitude, high inclination, geostationary orbits, in connection with solar effects and that of shielding. Data from active detectors flown in Spacelabs 1 and 2 suggest that a variety of phenomena must be understood before the effects of long-term exposure at the space-station type of orbit and shielding can be properly assessed.

A system for monitoring the radiation effects of a proton linear accelerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Skorkin, V. M., E-mail: skorkin@inr.ru; Belyanski, K. L.; Skorkin, A. V.

2016-12-15

The system for real-time monitoring of radioactivity of a high-current proton linear accelerator detects secondary neutron emission from proton beam losses in transport channels and measures the activity of radionuclides in gas and aerosol emissions and the radiation background in the environment affected by a linear accelerator. The data provided by gamma, beta, and neutron detectors are transferred over a computer network to the central server. The system allows one to monitor proton beam losses, the activity of gas and aerosol emissions, and the radiation emission level of a linear accelerator in operation.

Calibration of the active radiation detector for Spacelab-One

NASA Technical Reports Server (NTRS)

1982-01-01

The flight models of the active radiation detector (ARD) for the ENV-01 environmental monitor were calibrated using gamma radiation. Measured sensitivities of the ion chambers were 6.1 + or - 0.3 micron rad per count for ARD S/N1, and 10.4 + or - 0.5 micron rad per count for ARD S/N2. Both were linear over the measured range 0.10 to 500 m/rad hour. The particle counters (proportional counters) were set to respond to approximately 85% of minimum ionizing particles of unit charge passing through them. These counters were also calibrated in the gamma field.

Lanthanum (III) regulates the nitrogen assimilation in soybean seedlings under ultraviolet-B radiation.

PubMed

Huang, Guangrong; Wang, Lihong; Zhou, Qing

2013-01-01

Ultraviolet-B (UV-B, 280-320 nm) radiation has seriously affected the growth of plants. Finding the technology/method to alleviate the damage of UV-B radiation has become a frontal topic in the field of environmental science. The pretreatment with rare earth elements (REEs) is an effective method, but the regulation mechanism of REEs is unknown. Here, the regulation effects of lanthanum (La(III)) on nitrogen assimilation in soybean seedlings (Glycine max L.) under ultraviolet-B radiation were investigated to elucidate the regulation mechanism of REEs on plants under UV-B radiation. UV-B radiation led to the inhibition in the activities of the key enzymes (nitrate reductase, glutamine synthetase, glutamate synthase) in the nitrogen assimilation, the decrease in the contents of nitrate and soluble proteins, as well as the increase in the content of amino acid in soybean seedlings. The change degree of UV-B radiation at the high level (0.45 W m(-2)) was higher than that of UV-B radiation at the low level (0.15 W m(-2)). The pretreatment with 20 mg L(-1) La(III) could alleviate the effects of UV-B radiation on the activities of nitrate reductase, glutamine synthetase, glutamate synthase, and glutamate dehydrogenase, promoting amino acid conversion and protein synthesis in soybean seedlings. The regulation effect of La(III) under UV-B radiation at the low level was better than that of UV-B radiation at the high level. The results indicated that the pretreatment with 20 mg L(-1) La(III) could alleviate the inhibition of UV-B radiation on nitrogen assimilation in soybean seedlings.

Apparatus and method for detecting gamma radiation

DOEpatents

Sigg, Raymond A.

1994-01-01

A high efficiency radiation detector for measuring X-ray and gamma radiation from small-volume, low-activity liquid samples with an overall uncertainty better than 0.7% (one sigma SD). The radiation detector includes a hyperpure germanium well detector, a collimator, and a reference source. The well detector monitors gamma radiation emitted by the reference source and a radioactive isotope or isotopes in a sample source. The radiation from the reference source is collimated to avoid attenuation of reference source gamma radiation by the sample. Signals from the well detector are processed and stored, and the stored data is analyzed to determine the radioactive isotope(s) content of the sample. Minor self-attenuation corrections are calculated from chemical composition data.

Darcy-Forchheimer flow of Maxwell nanofluid flow with nonlinear thermal radiation and activation energy

NASA Astrophysics Data System (ADS)

Sajid, T.; Sagheer, M.; Hussain, S.; Bilal, M.

2018-03-01

The present article is about the study of Darcy-Forchheimer flow of Maxwell nanofluid over a linear stretching surface. Effects like variable thermal conductivity, activation energy, nonlinear thermal radiation is also incorporated for the analysis of heat and mass transfer. The governing nonlinear partial differential equations (PDEs) with convective boundary conditions are first converted into the nonlinear ordinary differential equations (ODEs) with the help of similarity transformation, and then the resulting nonlinear ODEs are solved with the help of shooting method and MATLAB built-in bvp4c solver. The impact of different physical parameters like Brownian motion, thermophoresis parameter, Reynolds number, magnetic parameter, nonlinear radiative heat flux, Prandtl number, Lewis number, reaction rate constant, activation energy and Biot number on Nusselt number, velocity, temperature and concentration profile has been discussed. It is viewed that both thermophoresis parameter and activation energy parameter has ascending effect on the concentration profile.

Decentralized Control of Sound Radiation using a High-Authority/Low-Authority Control Strategy with Anisotropic Actuators

NASA Technical Reports Server (NTRS)

Schiller, Noah H.; Cabell, Randolph H.; Fuller, Chris R.

2008-01-01

This paper describes a combined control strategy designed to reduce sound radiation from stiffened aircraft-style panels. The control architecture uses robust active damping in addition to high-authority linear quadratic Gaussian (LQG) control. Active damping is achieved using direct velocity feedback with triangularly shaped anisotropic actuators and point velocity sensors. While active damping is simple and robust, stability is guaranteed at the expense of performance. Therefore the approach is often referred to as low-authority control. In contrast, LQG control strategies can achieve substantial reductions in sound radiation. Unfortunately, the unmodeled interaction between neighboring control units can destabilize decentralized control systems. Numerical simulations show that combining active damping and decentralized LQG control can be beneficial. In particular, augmenting the in-bandwidth damping supplements the performance of the LQG control strategy and reduces the destabilizing interaction between neighboring control units.

A Study of Aerosol Direct Radiative Effect and Its Impacts on Global Terrestrial Ecosystem Cycles

NASA Astrophysics Data System (ADS)

Zhang, J.; Shao, S.; Zhou, L.

2017-12-01

Aerosols can absorb and scatter solar radiation, thus cause the total solar radiation reaching the surface to drop and the fraction of diffuse radiation to increase, which influence the surface radiation budget. The global surface radiation with and without consideration of aerosols are calculated by the Fu-Liou atmospheric radiative transfer model based on the MODIS aerosol products, CERES cloud products and other remote sensing data. The aerosol direct radiative effect is calculated based on the two scenarios of aerosols. Our calculation showed that in 2007, aerosols decreased the global total radiation by 9.16 W m-2 on average. Large decrease generally occurred in places with high AOD. As for the diffuse radiation, aerosol-induced changes were either positive or negative. Large increase generally occurred in places with high surface albedo, while large decrease generally occurred in places with high cloud fraction. The global aerosol-induced diffuse radiation change averaged 8.17 W m-2 in 2007. The aerosol direct radiative effect causes the photosynthetic active radiation to increase, and its influences on the global carbon cycle of terrestrial ecosystem are studied by using the Community Land Model (CLM). Calculations show that the aerosol direct radiative effects caused the global averages of terrestrial gross primary productivity (GPP), net primary productivity (NPP), heterotrophic respiration (RH), autotrophic respiration (RA), and net ecosystem productivity (Reco) to increase in 2007, with significant spatial variations however. The global average changes of GPP, NPP, NEP, RA, RH and Reco in 2007 were +6.47 gC m-2, +2.23 gC m-2, +0.34 gC m-2, +4.24 gC m-2, +1.89 gC m-2, +6.13 gC m-2, respectively. Examinations of the carbon fluxes show that the aerosol direct radiative effects influence the terrestrial ecosystem carbon cycles via the following two approaches: First, the diffuse fertilization effect, i.e. more diffuse radiation absorbed by vegetation shade leaves (photosynthetic active radiation, PAR) results in higher photosynthetic rates; Second, the radiation changes lead to changes in temperature and humidity, thereby changing the rates of the plant biophysical and chemical processes.

Current issues and actions in radiation protection of patients.

PubMed

Holmberg, Ola; Malone, Jim; Rehani, Madan; McLean, Donald; Czarwinski, Renate

2010-10-01

Medical application of ionizing radiation is a massive and increasing activity globally. While the use of ionizing radiation in medicine brings tremendous benefits to the global population, the associated risks due to stochastic and deterministic effects make it necessary to protect patients from potential harm. Current issues in radiation protection of patients include not only the rapidly increasing collective dose to the global population from medical exposure, but also that a substantial percentage of diagnostic imaging examinations are unnecessary, and the cumulative dose to individuals from medical exposure is growing. In addition to this, continued reports on deterministic injuries from safety related events in the medical use of ionizing radiation are raising awareness on the necessity for accident prevention measures. The International Atomic Energy Agency is engaged in several activities to reverse the negative trends of these current issues, including improvement of the justification process, the tracking of radiation history of individual patients, shared learning of safety significant events, and the use of comprehensive quality audits in the clinical environment. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Effects of radiation on DNA's double helix

NASA Technical Reports Server (NTRS)

2003-01-01

The blueprint of life, DNA's double helix is found in the cells of everything from bacteria to astronauts. Exposure to radiation(depicted at right) such as X-rays (upper) or heavy ion particles (lower), can damage DNA and cause dire consequences both to the organism itself and to future generations. One of NASA's main goals is to develop better radiation shielding materials to protect astronauts from destructive radiation in space. This is particularly important for long space missions. NASA has selected researchers to study materials that provide better shielding. This research is managed by NASA's Office of Biological and Physical Research and is supported by the Microgravity Science and Applications Department at NASA's Marshall Center. During International Space Station Expedition Six, the Extravehicular Activity Radiation Monitoring (EVARM) will continue to measure radiation dosage encountered by the eyes, internal organs and skin during specific spacewalks, and relate it to the type of activity, location and other factors. An analysis of this information may be useful in mitigating potential exposure to space walkers in the future. (Illustration by Dr. Frank Cucinotta, NASA/Johnson Space Center, and Prem Saganti, Lockheed Martin)

Loss of β-catenin triggers oxidative stress and impairs hematopoietic regeneration

PubMed Central

Lento, William; Ito, Takahiro; Zhao, Chen; Harris, Jeffrey R.; Huang, Wei; Jiang, Chen; Owzar, Kouros; Piryani, Sadhna; Racioppi, Luigi; Chao, Nelson; Reya, Tannishtha

2014-01-01

Accidental or deliberate ionizing radiation exposure can be fatal due to widespread hematopoietic destruction. However, little is known about either the course of injury or the molecular pathways that regulate the subsequent regenerative response. Here we show that the Wnt signaling pathway is critically important for regeneration after radiation-induced injury. Using Wnt reporter mice, we show that radiation triggers activation of Wnt signaling in hematopoietic stem and progenitor cells. β-Catenin-deficient mice, which lack the ability to activate canonical Wnt signaling, exhibited impaired hematopoietic stem cell regeneration and bone marrow recovery after radiation. We found that, as part of the mechanism, hematopoietic stem cells lacking β-catenin fail to suppress the generation of reactive oxygen species and cannot resolve DNA double-strand breaks after radiation. Consistent with the impaired response to radiation, β-catenin-deficient mice are also unable to recover effectively after chemotherapy. Collectively, these data indicate that regenerative responses to distinct hematopoietic injuries share a genetic dependence on β-catenin and raise the possibility that modulation of Wnt signaling may be a path to improving bone marrow recovery after damage. PMID:24788518

Ferulic acid (FA) abrogates γ-radiation induced oxidative stress and DNA damage by up-regulating nuclear translocation of Nrf2 and activation of NHEJ pathway.

PubMed

Das, Ujjal; Manna, Krishnendu; Khan, Amitava; Sinha, Mahuya; Biswas, Sushobhan; Sengupta, Aaveri; Chakraborty, Anindita; Dey, Sanjit

2017-01-01

The present study was aimed to evaluate the radioprotective effect of ferulic acid (FA), a naturally occurring plant flavonoid in terms of DNA damage and damage related alterations of repair pathways by gamma radiation. FA was administered at a dose of 50 mg/kg body weight for five consecutive days prior to exposing the swiss albino mice to a single dose of 10 Gy gamma radiation. Ionising radiation induces oxidative damage manifested by decreased expression of Cu, Zn-SOD (SOD stands for super oxide dismutase), Mn-SOD and catalase. Gamma radiation promulgated reactive oxygen species (ROS) mediated DNA damage and modified repair pathways. ROS enhanced nuclear translocation of p53, activated ATM (ataxia telangiectasia-mutated protein), increased expression of GADD45a (growth arrest and DNA-damage-inducible protein) gene and inactivated Non homologous end joining (NHEJ) repair pathway. The comet formation in irradiated mice peripheral blood mononuclear cells (PBMC) reiterated the DNA damage in IR exposed groups. FA pretreatment significantly prevented the comet formation and regulated the nuclear translocation of p53, inhibited ATM activation and expression of GADD45a gene. FA promoted the nuclear translocation of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and activated NHEJ repair pathway to overcome ROS mediated oxidative stress and DNA damage. Therefore, the current study stated that FA can challenge the oxidative stress by (i) inducing nuclear translocation of Nrf2, (ii) scavenging ROS, and (iii) activating NHEJ DNA repair process.

Monolithic active pixel radiation detector with shielding techniques

DOEpatents

Deptuch, Grzegorz W.

2018-03-20

A monolithic active pixel radiation detector including a method of fabricating thereof. The disclosed radiation detector can include a substrate comprising a silicon layer upon which electronics are configured. A plurality of channels can be formed on the silicon layer, wherein the plurality of channels are connected to sources of signals located in a bulk part of the substrate, and wherein the signals flow through electrically conducting vias established in an isolation oxide on the substrate. One or more nested wells can be configured from the substrate, wherein the nested wells assist in collecting charge carriers released in interaction with radiation and wherein the nested wells further separate the electronics from the sensing portion of the detector substrate. The detector can also be configured according to a thick SOA method of fabrication.

Monolithic active pixel radiation detector with shielding techniques

DOEpatents

Deptuch, Grzegorz W.

2016-09-06

A monolithic active pixel radiation detector including a method of fabricating thereof. The disclosed radiation detector can include a substrate comprising a silicon layer upon which electronics are configured. A plurality of channels can be formed on the silicon layer, wherein the plurality of channels are connected to sources of signals located in a bulk part of the substrate, and wherein the signals flow through electrically conducting vias established in an isolation oxide on the substrate. One or more nested wells can be configured from the substrate, wherein the nested wells assist in collecting charge carriers released in interaction with radiation and wherein the nested wells further separate the electronics from the sensing portion of the detector substrate. The detector can also be configured according to a thick SOA method of fabrication.

[Allelopathic effects of Lycoris radiate on radish, cucumber, tomato and rape seedlings].

PubMed

Jiang, Hongyun; Zhang, Yanning; Feng, Pingzhang; Zhang, Heng

2006-09-01

The laboratory test showed that Lycoris radiate water extract had a stronger inhibitory effect on the seed germination and seedling growth of radish, cucumber, tomato and rape. After treated with 0.0125 g x ml(-1) of the extract, tomato seed could not germinate, but the seed germination inhibition rate of rape, radish and cucumber was only 17.73%, 14.97% and 2.65%, respectively. Under the same concentrations of the extract, sprout growth was inhibited more strongly than root growth. L. radiate methanol extract could inhibit the sprout and root growth of endosperm-removed wheat and sorghum, and the effect was stronger for sorghum than for wheat. All of these illustrated that L. radiate extracts mainly inhibited non-photosynthesis activity, but could also inhibit photosynthesis activity to some degree.

Inclusion of an ultraviolet radiation transfer component in an urban forest effects model for predicting tree influences on potential below-canopy exposure to UVB radiation

Treesearch

Gordon M. Heisler; Richard H. Grant; David J. Nowak; Wei Gao; Daniel E. Crane; Jeffery T. Walton

2003-01-01

Evaluating the impact of ultraviolet-B radiation (UVB) on urban populations would be enhanced by improved predictions of the UVB radiation at the level of human activity. This paper reports the status of plans for incorporating a UVB prediction module into an existing Urban Forest Effects (UFORE) model. UFORE currently has modules to quantify urban forest structure,...

Summary of ionizing radiation analysis on the Long Duration Exposure Facility

NASA Technical Reports Server (NTRS)

Parnell, T. A.

1991-01-01

The Ionizing Radiation Special Investigation Group (IRSIG) for the Long Duration Exposure Facility (LDEF) was established to perform radiation measurements and analysis not planned in the original experiments, and to assure availability of LDEF analysis results in a form useful to future missions. The IRSIG has organized extensive induced radioactivity measurements throughout LDEF, and a comprehensive program to compare the LDEF radiation measurements to values calculated using environment models. The activities and present status of the Group is described. The ionizing radiation results presented is summarized.

Methods of and apparatus for radiation measurement, and specifically for in vivo radiation measurement

DOEpatents

Huffman, D.D.; Hughes, R.C.; Kelsey, C.A.; Lane, R.; Ricco, A.J.; Snelling, J.B.; Zipperian, T.E.

1986-08-29

Methods of and apparatus for in vivo radiation measurements rely on a MOSFET dosimeter of high radiation sensitivity which operates in both the passive mode to provide an integrated dose detector and active mode to provide an irradiation rate detector. A compensating circuit with a matched unirradiated MOSFET is provided to operate at a current designed to eliminate temperature dependence of the device. Preferably, the MOSFET is rigidly mounted in the end of a miniature catheter and the catheter is implanted in the patient proximate the radiation source.

TAO kinases mediate activation of p38 in response to DNA damage

PubMed Central

Raman, Malavika; Earnest, Svetlana; Zhang, Kai; Zhao, Yingming; Cobb, Melanie H

2007-01-01

Thousand and one amino acid (TAO) kinases are Ste20p-related MAP kinase kinase kinases (MAP3Ks) that activate p38 MAPK. Here we show that the TAO kinases mediate the activation of p38 in response to various genotoxic stimuli. TAO kinases are activated acutely by ionizing radiation, ultraviolet radiation, and hydroxyurea. Full-length and truncated fragments of dominant negative TAOs inhibit the activation of p38 by DNA damage. Inhibition of TAO expression by siRNA also decreases p38 activation by these agents. Cells in which TAO kinases have been knocked down are less capable of engaging the DNA damage-induced G2/M checkpoint and display increased sensitivity to IR. The DNA damage kinase ataxia telangiectasia mutated (ATM) phosphorylates TAOs in vitro; radiation induces phosphorylation of TAO on a consensus site for phosphorylation by the ATM protein kinase in cells; and TAO and p38 activation is compromised in cells from a patient with ataxia telangiectasia that lack ATM. These findings indicate that TAO kinases are regulators of p38-mediated responses to DNA damage and are intermediates in the activation of p38 by ATM. PMID:17396146

Energy release, beam attenuation radiation damage, gas production and accumulation of long-lived activity in Pb, Pb-Bi and Hg targets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shubin, Yu.N.

1996-06-01

The calculation and analysis of the nuclei concentrations and long-lived residual radioactivity accumulated in Pb, Pb-Bi and Hg targets irradiated by 800 MeV, 30 mA proton beam have been performed. The dominating components to the total radioactivity of radionuclides resulting from fission and spallation reactions and radiative capture by both target nuclei and accumulated radioactive nuclei for various irradiation and cooling times were analyzed. The estimations of spectral component contributions of neutron and proton fluxes to the accumulated activity were carried out. The contributions of fission products to the targets activity and partial activities of main long-lived fission products tomore » the targets activity and partial activities of main long-lived fission products were evaluated. The accumulation of Po isotopes due to reactions induced by secondary alpha-particles were found to be important for the Pb target as compared with two-step radiative capture. The production of Tritium in the targets and its contribution to the total targets activity was considered in detail. It is found that total activities of both targets are close to one another.« less

Monte Carlo simulations for the space radiation superconducting shield project (SR2S).

PubMed

Vuolo, M; Giraudo, M; Musenich, R; Calvelli, V; Ambroglini, F; Burger, W J; Battiston, R

2016-02-01

Astronauts on deep-space long-duration missions will be exposed for long time to galactic cosmic rays (GCR) and Solar Particle Events (SPE). The exposure to space radiation could lead to both acute and late effects in the crew members and well defined countermeasures do not exist nowadays. The simplest solution given by optimized passive shielding is not able to reduce the dose deposited by GCRs below the actual dose limits, therefore other solutions, such as active shielding employing superconducting magnetic fields, are under study. In the framework of the EU FP7 SR2S Project - Space Radiation Superconducting Shield--a toroidal magnetic system based on MgB2 superconductors has been analyzed through detailed Monte Carlo simulations using Geant4 interface GRAS. Spacecraft and magnets were modeled together with a simplified mechanical structure supporting the coils. Radiation transport through magnetic fields and materials was simulated for a deep-space mission scenario, considering for the first time the effect of secondary particles produced in the passage of space radiation through the active shielding and spacecraft structures. When modeling the structures supporting the active shielding systems and the habitat, the radiation protection efficiency of the magnetic field is severely decreasing compared to the one reported in previous studies, when only the magnetic field was modeled around the crew. This is due to the large production of secondary radiation taking place in the material surrounding the habitat. Copyright © 2016 The Committee on Space Research (COSPAR). Published by Elsevier Ltd. All rights reserved.