Emilio G. Segrè - Patents

Science.gov Websites

neutrons to thermal energies. US 2,573,069 METHOD AND APPARATUS FOR MEASURING STRONG ALPHA EMITTERS - Segrà ¨, E. G.; October 30, 1951 (to the U.S. Atomic Energy Commission) This patent describes an apparatus and method for the determination of the strength of a strong alpha emitter. The apparatus is so

Radioactive sample effects on EDXRF spectra

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

Worley, Christopher G

2008-01-01

Energy dispersive X-ray fluorescence (EDXRF) is a rapid, straightforward method to determine sample elemental composition. A spectrum can be collected in a few minutes or less, and elemental content can be determined easily if there is adequate energy resolution. Radioactive alpha emitters, however, emit X-rays during the alpha decay process that complicate spectral interpretation. This is particularly noticeable when using a portable instrument where the detector is located in close proximity to the instrument analysis window held against the sample. A portable EDXRF instrument was used to collect spectra from specimens containing plutonium-239 (a moderate alpha emitter) and americium-241 (amore » heavy alpha emitter). These specimens were then analyzed with a wavelength dispersive XRF (WDXRF) instrument to demonstrate the differences to which sample radiation-induced X-ray emission affects the detectors on these two types of XRF instruments.« less

Measurement system for alpha emitters in solution

NASA Astrophysics Data System (ADS)

Robert, A.; Sella, C.; Heindl, R.

1984-08-01

The measurement of alpha emitter concentrations in solution corresponds to a need felt in particular by laboratories working on actinides and in the spent fuel reprocessing industry. The instrument present here allows this measurement continuously by the use of a new scintillator that is insensitive to corrosive liquids. The extreme thinness of the scintillator guarantees good detection selectivity of alpha particles in the presence of beta and gamma emissions. Examples of uranium-233, plutonium-239 and americium-241 concentration measurements are presented.

Studying Lyman-alpha escape and reionization in Green Pea galaxies

NASA Astrophysics Data System (ADS)

Yang, Huan; Malhotra, Sangeeta; Rhoads, James E.; Gronke, Max; Leitherer, Claus; Wofford, Aida; Dijkstra, Mark

2017-01-01

Green Pea galaxies are low-redshift galaxies with extreme [OIII]5007 emission line. We built the first statistical sample of Green Peas observed by HST/COS and used them as analogs of high-z Lyman-alpha emitters to study Ly-alpha escape and Ly-alpha sizes. Using the HST/COS 2D spectra, we found that Ly-alpha sizes of Green Peas are larger than the UV continuum sizes. We found many correlations between Ly-alpha escape fraction and galactic properties -- dust extinction, Ly-alpha kinematic features, [OIII]/[OII] ratio, and gas outflow velocities. We fit an empirical relation to predict Ly-alpha escape fraction from dust extinction and Ly-alpha red-peak velocity. In the JWST era, we can use this relation to derive the IGM HI column density along the line of sight of each high-z Ly-alpha emitter and probe the reionization process.

Risk of Lung Cancer Mortality in Nuclear Workers from Internal Exposure to Alpha Particle-emitting Radionuclides

PubMed Central

Atkinson, Will; Bérard, Philippe; Bingham, Derek; Birchall, Alan; Blanchardon, Eric; Bull, Richard; Guseva Canu, Irina; Challeton-de Vathaire, Cécile; Cockerill, Rupert; Do, Minh T.; Engels, Hilde; Figuerola, Jordi; Foster, Adrian; Holmstock, Luc; Hurtgen, Christian; Laurier, Dominique; Puncher, Matthew; Riddell, Anthony E.; Samson, Eric; Thierry-Chef, Isabelle; Tirmarche, Margot; Vrijheid, Martine; Cardis, Elisabeth

2017-01-01

Background: Carcinogenic risks of internal exposures to alpha-emitters (except radon) are poorly understood. Since exposure to alpha particles—particularly through inhalation—occurs in a range of settings, understanding consequent risks is a public health priority. We aimed to quantify dose–response relationships between lung dose from alpha-emitters and lung cancer in nuclear workers. Methods: We conducted a case–control study, nested within Belgian, French, and UK cohorts of uranium and plutonium workers. Cases were workers who died from lung cancer; one to three controls were matched to each. Lung doses from alpha-emitters were assessed using bioassay data. We estimated excess odds ratio (OR) of lung cancer per gray (Gy) of lung dose. Results: The study comprised 553 cases and 1,333 controls. Median positive total alpha lung dose was 2.42 mGy (mean: 8.13 mGy; maximum: 316 mGy); for plutonium the median was 1.27 mGy and for uranium 2.17 mGy. Excess OR/Gy (90% confidence interval)—adjusted for external radiation, socioeconomic status, and smoking—was 11 (2.6, 24) for total alpha dose, 50 (17, 106) for plutonium, and 5.3 (−1.9, 18) for uranium. Conclusions: We found strong evidence for associations between low doses from alpha-emitters and lung cancer risk. The excess OR/Gy was greater for plutonium than uranium, though confidence intervals overlap. Risk estimates were similar to those estimated previously in plutonium workers, and in uranium miners exposed to radon and its progeny. Expressed as risk/equivalent dose in sieverts (Sv), our estimates are somewhat larger than but consistent with those for atomic bomb survivors. See video abstract at, http://links.lww.com/EDE/B232. PMID:28520643

Lower thresholds for lifetime health effects in mammals from high-LET radiation - Comparison with chronic low-LET radiation.

PubMed

Sazykina, Tatiana G; Kryshev, Alexander I

2016-12-01

Lower threshold dose rates and confidence limits are quantified for lifetime radiation effects in mammalian animals from internally deposited alpha-emitting radionuclides. Extensive datasets on effects from internal alpha-emitters are compiled from the International Radiobiological Archives. In total, the compiled database includes 257 records, which are analyzed by means of non-parametric order statistics. The generic lower threshold for alpha-emitters in mammalian animals (combined datasets) is 6.6·10 -5  Gy day -1 . Thresholds for individual alpha-emitting elements differ considerably: plutonium and americium - 2.0·10 -5  Gy day -1 ; radium - 2.1·10 -4  Gy day -1 . Threshold for chronic low-LET radiation is previously estimated at 1·10 -3  Gy day -1 . For low exposures, the following values of alpha radiation weighting factor w R for internally deposited alpha-emitters in mammals are quantified: w R (α) = 15 as a generic value for the whole group of alpha-emitters; w R (Pu) = 50 for plutonium; w R (Am) = 50 for americium; w R (Ra) = 5 for radium. These values are proposed to serve as radiation weighting factors in calculations of equivalent doses to non-human biota. The lower threshold dose rate for long-lived mammals (dogs) is significantly lower than comparing with the threshold for short-lived mammals (mice): 2.7·10 -5  Gy day -1 , and 2.0·10 -4  Gy day -1 , respectively. The difference in thresholds is exactly reflecting the relationship between the natural longevity of these two species. Graded scale of severity in lifetime radiation effects in mammals is developed, based on compiled datasets. Being placed on the severity scale, the effects of internal alpha-emitters are situated in the zones of considerably lower dose rates than effects of the same severity caused by low-LET radiation. RBE values, calculated for effects of equal severity, are found to depend on the intensity of chronic exposure: different RBE values are characteristic for low, moderate, and high lifetime exposures (30, 70, and 13, respectively). The results of the study provide a basis for selecting correct values of radiation weighting factors in dose assessment to non-human biota. Copyright © 2016 Elsevier Ltd. All rights reserved.

Measuring Beam Sizes and Ultra-Small Electron Emittances Using an X-ray Pinhole Camera.

PubMed

Elleaume, P; Fortgang, C; Penel, C; Tarazona, E

1995-09-01

A very simple pinhole camera set-up has been built to diagnose the electron beam emittance of the ESRF. The pinhole is placed in the air next to an Al window. An image is obtained with a CCD camera imaging a fluorescent screen. The emittance is deduced from the size of the image. The relationship between the measured beam size and the electron beam emittance depends upon the lattice functions alpha, beta and eta, the screen resolution, pinhole size and photon beam divergence. The set-up is capable of measuring emittances as low as 5 pm rad and is presently routinely used as both an electron beam imaging device and an emittance diagnostic.

MOLECULAR SIEVES ADSORB IODINE-131 FROM AIR

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

Wahlgren, M.A.; Meinke, W.W.

1957-09-01

Consideration has been given to the problem of separating and estimating U, Po, nnd other alpha emitters (in order to provide analytical methods for their routine determination in conformity with the draft agreement on the Harwell effluent). Uranium may be ether extracted from solutions of NH/sub 4/NO/sub 3/ as salting out agent at pH1 with an efficiency of 98 to 99%. The deposition of Po on Ag foil is a specific method for this element and under prescribed conditions similar extraction efficiencies may be obtained. An adequate separation from all "other alpha emitters" is obtained and methods for the estimationmore » of these are discussed. A comprehensive scheme involving a preliminary activity concentration step has been elaborated. U, Po, and the majority of the "other alpha emitters" are precipitated as their tannin complexes at pH8 using Ca(OH)/sub 2/, the calcium-tannin complex acting as a carrier. That part of the activity remaining in solution is determined as in the total activity method, previously described. From the solution of the precipitate, Po is first separated by electrodeposition, and then U by ether extraction in the presence of NH/sub 4/NO/sub 3/. The majority of the "other alpha emitters" still in the aqueous NH/sub 4/NO/sub 3/ solution are collected on a second calcium-tannin precipitate, while the small part remaining in solution after this operation is obtained by direct evaporation. (auth)« less

A novel controlled release ethanol emitter: preparation and effect on some postharvest quality parameters of Chinese bayberry during storage.

PubMed

Mu, Honglei; Gao, Haiyan; Chen, Hangjun; Fang, Xiangjun; Han, Qiang

2017-11-01

Reducing spoilage and prolonging the shelf-life of food materials are both critically important in the food industry. Among the many available preservatives, ethanol has been widely used for the storage of fruits and vegetables. Although a few ethanol emitters are available in the form of antimicrobial packaging, these ethanol emitters demonstrate high volatility, uncontrolled release and other disadvantages, and so the practical applications are limited. A novel ethanol gel with a controlled release rate was prepared by a gelatification reaction between ethanol and sodium stearate to overcome the disadvantage of conventional ethanol emitters. The hardness, adhesiveness and cohesiveness of developed ethanol gels increased, whereas the springiness decreased along with an increase in the sodium stearate concentration. The release rate of ethanol in the gels was controlled by the concentration of sodium stearate, in which a first-order release kinetic was observed. The release rate constant (k) of the gels with 12.5, 37.5, 62.5 g kg -1 of sodium stearate was 0.58 ± 0.029, 0.49 ± 0.035 and 0.41 ± 0.021 h -1 , respectively, at 25 °C. The application of the controlled release ethanol emitter with respect to the storage of Chinese bayberry fruit demonstrated its ability to reduce the decay rate, maintain firmness and inhibit increased malondialdehyde content at 4 °C. In terms of practical applications, an appropriate sodium stearate content can be selected in accordance with the storage period, aiming to achieve precise storage goals. Therefore, the ethanol emitter has potential application prospects as an active packaging for Chinese bayberry fruit, as well as for other perishable products. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Extending lifetimes of lanthanide-based near-infrared emitters (Nd, Yb) in the millisecond range through Cr(III) sensitization in discrete bimetallic edifices.

PubMed

Imbert, Daniel; Cantuel, Martine; Bünzli, Jean-Claude G; Bernardinelli, Gérald; Piguet, Claude

2003-12-24

A [Cr(alpha,alpha'-diimine)3]3+ chromophore is used as a donor for sensitizing NdIII and YbIII near-infrared (NIR) emitters in the heterobimetallic helicates [LnCrIIIL3]6+. The intramolecular CrIII --> LnIII energy transfer process controls the population of the lanthanide-centered emitting levels, thus leading to unprecedented extension of the NIR luminescence decay times in the millisecond range for Nd and Yb ions incorporated in coordination complexes.

High-absorptance high-emittance anodic coating

NASA Technical Reports Server (NTRS)

Le, Huong Giang (Inventor); Chesterfield, John L. (Inventor)

1999-01-01

A colored anodic coating for use on surfaces of substrates, e.g. aluminum substrates in which it is desirable to maintain a high solar absorptance (.alpha.) and a high infrared emittance (.epsilon.), particularly in low earth orbit space environments. This anodic coating is preferably a dark colored coating, and even more preferably a black coating. This coating allows a touch temperature within an acceptable design range to preclude burning of an astronaut in case of contact, but also allows a solar radiation absorption in an amount such that an .alpha./.epsilon. ratio of unity is achieved. The coating of the invention comprises a first layer in the form of an acid anodized colored anodic layer for achieving a high solar absorptance and a second or high emittance layer in the form of a clear acid anodized layer for achieving a high emittance. The entire coating is quite thin, e.g. 1-2 mils and is quite stable in a hostile space environment of the type encountered in a low earth orbit. The coating is obtained by first creating the high emittance clear anodized coating on the metal surface followed by anodizing using a colored anodizing process.

Variable Emittance Electrochromics Using Ionic Electrolytes and Low Solar Absorptance Coatings

NASA Technical Reports Server (NTRS)

Chandrasekhar, Prasanna

2011-01-01

One of the last remaining technical hurdles with variable emittance devices or skins based on conducting polymer electrochromics is the high solar absorptance of their top surfaces. This high solar absorptance causes overheating of the skin when facing the Sun in space. Existing technologies such as mechanical louvers or loop heat pipes are virtually inapplicable to micro (< 20 kg) and nano (< 5 kg) spacecraft. Novel coatings lower the solar absorption to Alpha(s) of between 0.30 and 0.46. Coupled with the emittance properties of the variable emittance skins, this lowers the surface temperature of the skins facing the Sun to between 30 and 60 C, which is much lower than previous results of 100 C, and is well within acceptable satellite operations ranges. The performance of this technology is better than that of current new technologies such as microelectromechanical systems (MEMS), electrostatics, and electrophoretics, especially in applications involving micro and nano spacecraft. The coatings are deposited inside a high vacuum, layering multiple coatings onto the top surfaces of variable emittance skins. They are completely transparent in the entire relevant infrared region (about 2 to 45 microns), but highly reflective in the visible-NIR (near infrared) region of relevance to solar absorptance.

Beta/alpha continuous air monitor

DOEpatents

Becker, Gregory K.; Martz, Dowell E.

1989-01-01

A single deep layer silicon detector in combination with a microcomputer, recording both alpha and beta activity and the energy of each pulse, distinguishing energy peaks using a novel curve fitting technique to reduce the natural alpha counts in the energy region where plutonium and other transuranic alpha emitters are present, and using a novel algorithm to strip out radon daughter contribution to actual beta counts.

Alpha/beta pulse shape discrimination in plastic scintillation using commercial scintillation detectors.

PubMed

Bagán, H; Tarancón, A; Rauret, G; García, J F

2010-06-18

Activity determination in different types of samples is a current need in many different fields. Simultaneously analysing alpha and beta emitters is now a routine option when using liquid scintillation (LS) and pulse shape discrimination. However, LS has an important drawback, the generation of mixed waste. Recently, several studies have shown the capability of plastic scintillation (PS) as an alternative to LS, but no research has been carried out to determine its capability for alpha/beta discrimination. The objective of this study was to evaluate the capability of PS to discriminate alpha/beta emitters on the basis of pulse shape analysis (PSA). The results obtained show that PS pulses had lower energy than LS pulses. As a consequence, a lower detection efficiency, a shift to lower energies and a better discrimination of beta and a worst discrimination of alpha disintegrations was observed for PS. Colour quenching also produced a decrease in the energy of the particles, as well as the effects described above. It is clear that in PS, the discrimination capability was correlated with the energy of the particles detected. Taking into account the discrimination capabilities of PS, a protocol for the measurement and the calculation of alpha and beta activities in mixtures using PS and commercial scintillation detectors has been proposed. The new protocol was applied to the quantification of spiked river water samples containing a pair of radionuclides ((3)H-(241)Am or (90)Sr/(90)Y-(241)Am) in different activity proportions. The relative errors in all determinations were lower than 7%. These results demonstrate the capability of PS to discriminate alpha/beta emitters on the basis of pulse shape and to quantify mixtures without generating mixed waste. 2010 Elsevier B.V. All rights reserved.

Beta/alpha continuous air monitor

DOEpatents

Becker, G.K.; Martz, D.E.

1988-06-27

A single deep layer silicon detector in combination with a microcomputer, recording both alpha and beta activity and the energy of each pulse, distinquishing energy peaks using a novel curve fitting technique to reduce the natural alpha counts in the energy region where plutonium and other transuranic alpha emitters are present, and using a novel algorithm to strip out radon daughter contribution to actual beta counts. 7 figs.

A Search for z>6.5 Lyman-alpha Emitting Galaxies with WISP

NASA Astrophysics Data System (ADS)

Bagley, Micaela B.; Scarlata, Claudia; Dai, Yu Sophia; Rafelski, Marc; Baronchelli, Ivano; Colbert, James W.; Dominguez, Alberto; Hathi, Nimish P.; Henry, Alaina L.; Malkan, Matthew Arnold; Martin, Crystal L.; Mehta, Vihang; Pahl, Anthony; Ross, Nathaniel; Rutkowski, Michael J.; Teplitz, Harry I.; WISP Team

2016-01-01

The observed number density of Lyman-alpha emitting galaxies at z>6 provides an important probe of the reionization history of the universe. Because Lyman-alpha photons are very sensitive to the presence of neutral hydrogen, the evolution of the galaxy number density above redshift 6 can be used as a measurement on the progress of reionization. However, the Lyman-alpha luminosity function is currently poorly constrained at high-z. We present the results of a systematic search for Lyman-alpha emitters (LAEs) at redshifts of ~6.5 to 7.5 using the HST WFC3 Infrared Spectroscopic Parallels (WISP) survey. WISP's uncorrelated fields are well-suited to the study of bright LAEs, minimizing the effects of clustering introduced by a patchy reionization. From the 30 deepest WISP fields, we compile a sample of single-line emitters, confirm redshifts with broadband colors, and identify LAE candidates that have "dropped out" (are undetected at the 1 sigma level) of the WFC3 UVIS filters. By combining our results with other z~7 studies, we determine whether the number density of LAEs evolves past z~6.5.

Dynamic radioactive particle source

DOEpatents

Moore, Murray E; Gauss, Adam Benjamin; Justus, Alan Lawrence

2012-06-26

A method and apparatus for providing a timed, synchronized dynamic alpha or beta particle source for testing the response of continuous air monitors (CAMs) for airborne alpha or beta emitters is provided. The method includes providing a radioactive source; placing the radioactive source inside the detection volume of a CAM; and introducing an alpha or beta-emitting isotope while the CAM is in a normal functioning mode.

Fabrication, characterization and simulation of 4H-SiC Schottky diode alpha particle detectors for pyroprocessing actinide monitoring

NASA Astrophysics Data System (ADS)

Garcia, Timothy Richard

Pyroprocessing is a method of using high-temperature molten salts and electric fields to separate and collect fuel isotopes of used nuclear fuel. It has been has been tested in the U.S. at Idaho National Laboratory as a key step in closing the nuclear fuel cycle. One technical problem with the pyroprocessing method is a lack of knowledge regarding the actinide concentrations in the salt bath during operation, since on-line techniques for measuring these concentrations are not presently available. 4H-SiC Schottky diode detectors can potentially fulfill this need. Such detectors would operate in contact with the molten salt, and measure concentrations via alpha-particle spectroscopy. This work seeks to fabricate and characterize 4H-SiC Schottky diode detectors at high temperature, model the alpha particle spectrum expected in a molten salt, and model the operation of the detectors to confirm the physics of operation is as expected. In this work, 4H-SiC Schottky diode detectors were fabricated at OSU Nanotech West. After fabrication, these detectors were characterized using both I-V curves and Am-241 alpha-particle energy spectra. All measurements were made as a function of temperature, from room temperature up to 500°C. The average energy required to create an electron-hole pair was observed to decrease with an increase of temperature, due to a decrease of both the 4H-SiC bandgap and non-linear energy loss terms. Furthermore, the FWHM of the spectra was observed to be dependent on the leakage current at a certain temperature, and not dependent on the temperature itself. Secondly, the alpha particle energy spectrum in the pyroprocessing environment was modeled using SRIM. The molten salt was modeled in 3 different geometries, with or without a protective cover material on top of the detector. Due to the loss of alpha-particle energy in the molten salt itself, a high-energy alpha emitter may completely cover the spectrum from a lower-energy alpha emitter. Each of the geometries simulated showed a different sensitivity to the lower-energy alpha emitter. Regardless of which geometry was modeled, it was observed that it is possible to measure both the emission energy of the alpha particles, as well as the concentration of the alpha emitter in the liquid. Lastly, Sentaurus TCAD was used to simulate the detection of alpha-particle charge collection in situations that are relevant to the molten salt alpha particle energy spectra. The effect of electric field negation was investigated, as well as velocity saturation. Finally, the dependence of charge recombination on temperature, alpha particle energy, and angle of incidence was investigated. These simulations captured the measurements performed at room temperature. With changed angle of incidence, the change in the amount of charge collected was less than 1 percent, indicating a weak dependence. Also, the amount of charge lost to Auger recombination was seen to increase with temperature. This disagrees with observations from experiment, indicating that the temperature dependence of one or more parameters of the model may not be accurate.

Predicting the Redshift 2 H-Alpha Luminosity Function Using [OIII] Emission Line Galaxies

NASA Technical Reports Server (NTRS)

Mehta, Vihang; Scarlata, Claudia; Colbert, James W.; Dai, Y. S.; Dressler, Alan; Henry, Alaina; Malkan, Matt; Rafelski, Marc; Siana, Brian; Teplitz, Harry I.;

Radioactivity levels in major French rivers: summary of monitoring chronicles acquired over the past thirty years and current status.

PubMed

Eyrolle, Frédérique; Claval, David; Gontier, Gilles; Antonelli, Christelle

2008-07-01

Since the beginning of the 1990 s, liquid releases of gamma-emitting radionuclides from French nuclear facilities have generally fallen by almost 85%. Almost 65% of gamma-emitting liquid effluents released into freshwater rivers concerned the River Rhône (Southeast France), with around 85% of this originating from the Marcoule spent fuel reprocessing plant. Upstream of French nuclear plants, artificial radionuclides still detected by gamma spectrometry in 2006, include (137)Cs, (131)I as well as (60)Co, (58)Co and (54)Mn in the case of the Rhine (Switzerland nuclear industries). In the wake of the fallout from the Chernobyl accident, (103)Ru, (106)Rh-Ru, (110 m)Ag, (141)Ce and (129)Te were detected in rivers in the east of France. Some of these radionuclides were found in aquatic plants until 1989. In eastern France, (137)Cs activity in river sediments and mosses is still today two to three times greater than that observed in similar environments in western France. No (134)Cs has been detected upstream of nuclear plants in French rivers since 2001. Downstream of nuclear plants, the gamma emitters still detected regularly in rivers in 2006 are (137)Cs, (134)Cs, (60)Co, (58)Co, (110 m)Ag, (54)Mn, (131)I, together with (241)Am downstream of the Marcoule spent fuel reprocessing plant. Alpha and beta emitters such as plutonium isotopes and (90)Sr first entered freshwaters at the early 1950s due to the leaching of soils contaminated by atmospheric fallout from nuclear testing. These elements were also introduced, in the case of the Rhône River, via effluent from the Marcoule reprocessing plant. Until the mid 1990 s, plutonium isotope levels observed in the lower reaches of the Rhône were 10 to 1000 times higher than those observed in other French freshwaters. Data gathered over a period of almost thirty years of radioecological studies reveal that the only radionuclides detected in fish muscles are (137)Cs, (90)Sr, plutonium isotopes and (241)Am. At the scale of the French territory, there is no significant difference since the mid 1990 s between (137)Cs activity observed downstream of nuclear facilities and that observed upstream, whether in sediments, mosses and fish. Finally, this study highlights that the natural radioactivity of surface freshwaters are around 25 times greater than artificial radioactivity from gamma emitters. However, non gamma emitters released by nuclear industries, such as (3)H, may lead to artificial activity levels 2 to 20 times higher than natural levels.

A simple, cost-effective emitter for controlled release of fish pheromones: development, testing, and application to management of the invasive sea lamprey

USGS Publications Warehouse

Wagner, Michael C.; Hanson, James E.; Meckley, Trevor D.; Johnson, Nicholas; Bals, Jason D.

2018-01-01

Semiochemicals that elicit species-specific attraction or repulsion have proven useful in the management of terrestrial pests and hold considerable promise for control of nuisance aquatic species, particularly invasive fishes. Because aquatic ecosystems are typically large and open, use of a semiochemical to control a spatially dispersed invader will require the development of a cost-effective emitter that is easy to produce, environmentally benign, inexpensive, and controls the release of the semiochemical without altering its structure. We examined the release properties of five polymers, and chose polyethylene glycol (PEG) as the best alternative. In a series of laboratory and field experiments, we examined the response of the invasive sea lamprey to PEG, and to a partial sex pheromone emitted from PEG that has proven effective as a trap bait to capture migrating sea lamprey prior to spawning. Our findings confirm that the sea lamprey does not behaviorally respond to PEG, and that the attractant response to the pheromone component was conserved when emitted from PEG. Further, we deployed the pheromone-PEG emitters as trap bait during typical control operations in three Great Lakes tributaries, observing similar improvements in trap performance when compared to a previous study using mechanically pumped liquid pheromone. Finally, the polymer emitters tended to dissolve unevenly in high flow conditions. We demonstrate that housing the emitter stabilizes the dissolution rate at high water velocity. We conclude the performance characteristics of PEG emitters to achieve controlled-release of a semiochemical are sufficient to recommend its use in conservation and management activities related to native and invasive aquatic organisms.

A simple, cost-effective emitter for controlled release of fish pheromones: Development, testing, and application to management of the invasive sea lamprey

PubMed Central

Meckley, Trevor D.; Johnson, Nicholas S.; Bals, Jason D.

2018-01-01

Semiochemicals that elicit species-specific attraction or repulsion have proven useful in the management of terrestrial pests and hold considerable promise for control of nuisance aquatic species, particularly invasive fishes. Because aquatic ecosystems are typically large and open, use of a semiochemical to control a spatially dispersed invader will require the development of a cost-effective emitter that is easy to produce, environmentally benign, inexpensive, and controls the release of the semiochemical without altering its structure. We examined the release properties of five polymers, and chose polyethylene glycol (PEG) as the best alternative. In a series of laboratory and field experiments, we examined the response of the invasive sea lamprey to PEG, and to a partial sex pheromone emitted from PEG that has proven effective as a trap bait to capture migrating sea lamprey prior to spawning. Our findings confirm that the sea lamprey does not behaviorally respond to PEG, and that the attractant response to the pheromone component was conserved when emitted from PEG. Further, we deployed the pheromone-PEG emitters as trap bait during typical control operations in three Great Lakes tributaries, observing similar improvements in trap performance when compared to a previous study using mechanically pumped liquid pheromone. Finally, the polymer emitters tended to dissolve unevenly in high flow conditions. We demonstrate that housing the emitter stabilizes the dissolution rate at high water velocity. We conclude the performance characteristics of PEG emitters to achieve controlled-release of a semiochemical are sufficient to recommend its use in conservation and management activities related to native and invasive aquatic organisms. PMID:29897927

A simple, cost-effective emitter for controlled release of fish pheromones: Development, testing, and application to management of the invasive sea lamprey.

PubMed

Wagner, C Michael; Hanson, James E; Meckley, Trevor D; Johnson, Nicholas S; Bals, Jason D

2018-01-01

Semiochemicals that elicit species-specific attraction or repulsion have proven useful in the management of terrestrial pests and hold considerable promise for control of nuisance aquatic species, particularly invasive fishes. Because aquatic ecosystems are typically large and open, use of a semiochemical to control a spatially dispersed invader will require the development of a cost-effective emitter that is easy to produce, environmentally benign, inexpensive, and controls the release of the semiochemical without altering its structure. We examined the release properties of five polymers, and chose polyethylene glycol (PEG) as the best alternative. In a series of laboratory and field experiments, we examined the response of the invasive sea lamprey to PEG, and to a partial sex pheromone emitted from PEG that has proven effective as a trap bait to capture migrating sea lamprey prior to spawning. Our findings confirm that the sea lamprey does not behaviorally respond to PEG, and that the attractant response to the pheromone component was conserved when emitted from PEG. Further, we deployed the pheromone-PEG emitters as trap bait during typical control operations in three Great Lakes tributaries, observing similar improvements in trap performance when compared to a previous study using mechanically pumped liquid pheromone. Finally, the polymer emitters tended to dissolve unevenly in high flow conditions. We demonstrate that housing the emitter stabilizes the dissolution rate at high water velocity. We conclude the performance characteristics of PEG emitters to achieve controlled-release of a semiochemical are sufficient to recommend its use in conservation and management activities related to native and invasive aquatic organisms.

The Elbmarsch leukemia cluster: are there conceptual limitations in controlling immission from nuclear establishments in Germany?

PubMed

Schmitz-Feuerhake, I; Dieckmann, H; Hoffmann, W; Lengfelder, E; Pflugbeil, S; Stevenson, A F

2005-11-01

The childhood leukemia cluster in the proximity of the German nuclear establishments of Geesthacht is unique in its spatial and temporal concentration. After a steep increase in cases in 1990, the cluster continues to show a significant increase up to the present. Early investigations of blood samples from a casual sample of local residents showed an increase in dicentric chromosomes in lymphocytes, indicating exposure exceeding dose limits. Analyses of the immission data revealed several unexpected deliveries of fission and activation products in the environment but provided no explanation of the source. Because of the observed overdispersion of dicentric chromosomes in cells, the idea of a contribution by densely ionizing emitters was compelling. The routine programs, however, do not include alpha emitters. These were measured in specific studies that proved contamination by transuranic nuclides. As shown in the present investigation, routine environmental surveillance programs support the occurrence of an accidental event near Geesthacht in September 1986. Until now, neither the cause nor the complete scenario of the activity release could be established. The ongoing discussion highlights limitations in the immission-control concept, which is predominantly based on gamma-radiation monitoring.

Quantitative Assessment of Detection Frequency for the INL Ambient Air Monitoring Network

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

Sondrup, A. Jeffrey; Rood, Arthur S.

A quantitative assessment of the Idaho National Laboratory (INL) air monitoring network was performed using frequency of detection as the performance metric. The INL air monitoring network consists of 37 low-volume air samplers in 31 different locations. Twenty of the samplers are located on INL (onsite) and 17 are located off INL (offsite). Detection frequencies were calculated using both BEA and ESER laboratory minimum detectable activity (MDA) levels. The CALPUFF Lagrangian puff dispersion model, coupled with 1 year of meteorological data, was used to calculate time-integrated concentrations at sampler locations for a 1-hour release of unit activity (1 Ci) formore » every hour of the year. The unit-activity time-integrated concentration (TICu) values were calculated at all samplers for releases from eight INL facilities. The TICu values were then scaled and integrated for a given release quantity and release duration. All facilities modeled a ground-level release emanating either from the center of the facility or at a point where significant emissions are possible. In addition to ground-level releases, three existing stacks at the Advanced Test Reactor Complex, Idaho Nuclear Technology and Engineering Center, and Material and Fuels Complex were also modeled. Meteorological data from the 35 stations comprising the INL Mesonet network, data from the Idaho Falls Regional airport, upper air data from the Boise airport, and three-dimensional gridded data from the weather research forecasting model were used for modeling. Three representative radionuclides identified as key radionuclides in INL’s annual National Emission Standards for Hazardous Air Pollutants evaluations were considered for the frequency of detection analysis: Cs-137 (beta-gamma emitter), Pu-239 (alpha emitter), and Sr-90 (beta emitter). Source-specific release quantities were calculated for each radionuclide, such that the maximum inhalation dose at any publicly accessible sampler or the National Emission Standards for Hazardous Air Pollutants maximum exposed individual location (i.e., Frenchman’s Cabin) was no more than 0.1 mrem yr–1 (i.e., 1% of the 10 mrem yr–1 standard). Detection frequencies were calculated separately for the onsite and offsite monitoring network. As expected, detection frequencies were generally less for the offsite sampling network compared to the onsite network. Overall, the monitoring network is very effective at detecting the potential releases of Cs-137 or Sr-90 from all sources/facilities using either the ESER or BEA MDAs. The network was less effective at detecting releases of Pu-239. Maximum detection frequencies for Pu-239 using ESER MDAs ranged from 27.4 to 100% for onsite samplers and 3 to 80% for offsite samplers. Using BEA MDAs, the maximum detection frequencies for Pu-239 ranged from 2.1 to 100% for onsite samplers and 0 to 5.9% for offsite samplers. The only release that was not detected by any of the samplers under any conditions was a release of Pu-239 from the Idaho Nuclear Technology and Engineering Center main stack (CPP-708). The methodology described in this report could be used to improve sampler placement and detection frequency, provided clear performance objectives are defined.« less

Switchable radioactive neutron source device

DOEpatents

Boyar, Robert E.; DeVolpi, Alexander; Stanford, George S.; Rhodes, Edgar A.

1989-01-01

This invention is a switchable neutron generating apparatus comprised of a pair of plates, the first plate having an alpha emitter section on it and the second plate having a target material portion on it which generates neutrons when its nuclei absorb an alpha particle. In operation, the alpha portion of the first plate is aligned with the neutron portion of the second plate to produce neutrons and brought out of alignment to cease production of neutrons.

Fluorescence-Assisted Gamma Spectrometry for Surface Contamination Analysis

NASA Astrophysics Data System (ADS)

Ihantola, Sakari; Sand, Johan; Perajarvi, Kari; Toivonen, Juha; Toivonen, Harri

2013-02-01

A fluorescence-based alpha-gamma coincidence spectrometry approach has been developed for the analysis of alpha-emitting radionuclides. The thermalization of alpha particles in air produces UV light, which in turn can be detected over long distances. The simultaneous detection of UV and gamma photons allows detailed gamma analyses of a single spot of interest even in highly active surroundings. Alpha particles can also be detected indirectly from samples inside sealed plastic bags, which minimizes the risk of cross-contamination. The position-sensitive alpha-UV-gamma coincidence technique reveals the presence of alpha emitters and identifies the nuclides ten times faster than conventional gamma spectrometry.

An overview of targeted alpha therapy with 225Actinium and 213Bismuth.

PubMed

Morgenstern, Alfred; Apostolidis, Christos; Kratochwil, Clemens; Sathekge, Mike; Krolicki, Leszek; Bruchertseifer, Frank

2018-05-01

Recent reports of the remarkable therapeutic efficacy of 225Ac-labeled PSMA-617 for therapy of metastatic castration-resistant prostate cancer have underlined the clinical potential of targeted alpha therapy. This review describes methods for the production of 225Ac and its daughter nuclide 213Bi and summarizes the current clinical experience with both alpha emitters with particular focus on recent studies of targeted alpha therapy of bladder cancer, brain tumors, neuroendocrine tumors and prostate cancer. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Switchable radioactive neutron source device

DOEpatents

Stanford, G.S.; Rhodes, E.A.; Devolpi, A.; Boyar, R.E.

1987-11-06

This invention is a switchable neutron generating apparatus comprised of a pair of plates, the first plate having an alpha emitter section on it and the second plate having a target material portion on it which generates neutrons when its nuclei absorb an alpha particle. In operation, the alpha portion of the first plate is aligned with the neutron portion of the second plate to produce neutrons and brought out of alignment to cease production of neutrons. 3 figs.

Porous Emitter Colloid Thruster Performance Characterization Using Optical Techniques

DTIC Science & Technology

2013-03-01

spacecraft. Liquid propellant has received a renewed interest as a viable propellant with the creation and proliferation of new ionic liquid compounds ...electrostatic gate) and collector (metallic plate) is unknown. Two factors cause this ambiguity, first, the gate needs to close fast enough to...simultaneously block all of the emitters and second, it is not directly known which emitter released the last particle hitting the collector plate

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

Eremenko, D. O.; Fotina, O. V.; Platonov, S. Yu.

The functional fitness of the alpha-emitter At-211 for radiotherapy of the thyroid gland cancer is evaluated. Radiation doses are calculated using the MIRD method and previously obtained pharmacokinetic data for At-211 in isotonic solution.

Recent {alpha} decay half-lives and analytic expression predictions including superheavy nuclei

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

Royer, G.; Zhang, H. F.

New recent experimental {alpha} decay half-lives have been compared with the results obtained from previously proposed formulas depending only on the mass and charge numbers of the {alpha} emitter and the Q{sub {alpha}} value. For the heaviest nuclei they are also compared with calculations using the Density-Dependent M3Y (DDM3Y) effective interaction and the Viola-Seaborg-Sobiczewski (VSS) formulas. The correct agreement allows us to make predictions for the {alpha} decay half-lives of other still unknown superheavy nuclei from these analytic formulas using the extrapolated Q{sub {alpha}} of G. Audi, A. H. Wapstra, and C. Thibault [Nucl. Phys. A729, 337 (2003)].

Test chamber for alpha spectrometry

DOEpatents

Larsen, Robert P.

1977-01-01

Alpha emitters for low-level radiochemical analysis by measurement of alpha spectra are positioned precisely with respect to the location of a surface-barrier detector by means of a chamber having a removable threaded planchet holder. A pedestal on the planchet holder holds a specimen in fixed engagement close to the detector. Insertion of the planchet holder establishes an O-ring seal that permits the chamber to be pumped to a desired vacuum. The detector is protected against accidental contact and resulting damage.

Quantitative single-particle digital autoradiography with α-particle emitters for targeted radionuclide therapy using the iQID camera

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

Miller, Brian W., E-mail: brian.miller@pnnl.gov; Frost, Sofia H. L.; Frayo, Shani L.

2015-07-15

Purpose: Alpha-emitting radionuclides exhibit a potential advantage for cancer treatments because they release large amounts of ionizing energy over a few cell diameters (50–80 μm), causing localized, irreparable double-strand DNA breaks that lead to cell death. Radioimmunotherapy (RIT) approaches using monoclonal antibodies labeled with α emitters may thus inactivate targeted cells with minimal radiation damage to surrounding tissues. Tools are needed to visualize and quantify the radioactivity distribution and absorbed doses to targeted and nontargeted cells for accurate dosimetry of all treatment regimens utilizing α particles, including RIT and others (e.g., Ra-223), especially for organs and tumors with heterogeneous radionuclidemore » distributions. The aim of this study was to evaluate and characterize a novel single-particle digital autoradiography imager, the ionizing-radiation quantum imaging detector (iQID) camera, for use in α-RIT experiments. Methods: The iQID camera is a scintillator-based radiation detection system that images and identifies charged-particle and gamma-ray/x-ray emissions spatially and temporally on an event-by-event basis. It employs CCD-CMOS cameras and high-performance computing hardware for real-time imaging and activity quantification of tissue sections, approaching cellular resolutions. In this work, the authors evaluated its characteristics for α-particle imaging, including measurements of intrinsic detector spatial resolutions and background count rates at various detector configurations and quantification of activity distributions. The technique was assessed for quantitative imaging of astatine-211 ({sup 211}At) activity distributions in cryosections of murine and canine tissue samples. Results: The highest spatial resolution was measured at ∼20 μm full width at half maximum and the α-particle background was measured at a rate as low as (2.6 ± 0.5) × 10{sup −4} cpm/cm{sup 2} (40 mm diameter detector area). Simultaneous imaging of multiple tissue sections was performed using a large-area iQID configuration (ø 11.5 cm). Estimation of the {sup 211}At activity distribution was demonstrated at mBq/μg-levels. Conclusions: Single-particle digital autoradiography of α emitters has advantages over traditional film-based autoradiographic techniques that use phosphor screens, in terms of spatial resolution, sensitivity, and activity quantification capability. The system features and characterization results presented in this study show that the iQID is a promising technology for microdosimetry, because it provides necessary information for interpreting alpha-RIT outcomes and for predicting the therapeutic efficacy of cell-targeted approaches using α emitters.« less

Quantitative single-particle digital autoradiography with α-particle emitters for targeted radionuclide therapy using the iQID camera.

PubMed

Miller, Brian W; Frost, Sofia H L; Frayo, Shani L; Kenoyer, Aimee L; Santos, Erlinda; Jones, Jon C; Green, Damian J; Hamlin, Donald K; Wilbur, D Scott; Fisher, Darrell R; Orozco, Johnnie J; Press, Oliver W; Pagel, John M; Sandmaier, Brenda M

2015-07-01

Alpha-emitting radionuclides exhibit a potential advantage for cancer treatments because they release large amounts of ionizing energy over a few cell diameters (50-80 μm), causing localized, irreparable double-strand DNA breaks that lead to cell death. Radioimmunotherapy (RIT) approaches using monoclonal antibodies labeled with α emitters may thus inactivate targeted cells with minimal radiation damage to surrounding tissues. Tools are needed to visualize and quantify the radioactivity distribution and absorbed doses to targeted and nontargeted cells for accurate dosimetry of all treatment regimens utilizing α particles, including RIT and others (e.g., Ra-223), especially for organs and tumors with heterogeneous radionuclide distributions. The aim of this study was to evaluate and characterize a novel single-particle digital autoradiography imager, the ionizing-radiation quantum imaging detector (iQID) camera, for use in α-RIT experiments. The iQID camera is a scintillator-based radiation detection system that images and identifies charged-particle and gamma-ray/x-ray emissions spatially and temporally on an event-by-event basis. It employs CCD-CMOS cameras and high-performance computing hardware for real-time imaging and activity quantification of tissue sections, approaching cellular resolutions. In this work, the authors evaluated its characteristics for α-particle imaging, including measurements of intrinsic detector spatial resolutions and background count rates at various detector configurations and quantification of activity distributions. The technique was assessed for quantitative imaging of astatine-211 ((211)At) activity distributions in cryosections of murine and canine tissue samples. The highest spatial resolution was measured at ∼20 μm full width at half maximum and the α-particle background was measured at a rate as low as (2.6 ± 0.5) × 10(-4) cpm/cm(2) (40 mm diameter detector area). Simultaneous imaging of multiple tissue sections was performed using a large-area iQID configuration (ø 11.5 cm). Estimation of the (211)At activity distribution was demonstrated at mBq/μg-levels. Single-particle digital autoradiography of α emitters has advantages over traditional film-based autoradiographic techniques that use phosphor screens, in terms of spatial resolution, sensitivity, and activity quantification capability. The system features and characterization results presented in this study show that the iQID is a promising technology for microdosimetry, because it provides necessary information for interpreting alpha-RIT outcomes and for predicting the therapeutic efficacy of cell-targeted approaches using α emitters.

Spatial resolution properties of digital autoradiography systems for pre-clinical alpha particle imaging (Conference Presentation)

NASA Astrophysics Data System (ADS)

Tanguay, Jesse; Benard, Francois; Celler, Anna; Ruth, Thomas; Schaffer, Paul

2017-03-01

Attaching alpha-emitting radionuclides to cancer-targeting agents increases the anti-tumor effects of targeted cancer therapies. The success of alpha therapy for treating bone metastases has increased interest in using targeted alpha therapy (TAT) to treat a broad spectrum of metastatic cancers. Estimating radiation doses to targeted tumors, including small (<250 μm) clusters of cancer cells, and to non-targeted tissues is critical in the pre-clinical development of TATs. However, accurate quantification of heterogeneous distributions of alpha-emitters in small metastases is not possible with existing pre-clinical in-vivo imaging systems. Ex-vivo digital autoradiography using a scintillator in combination with an image intensifier and a charged coupled device (CCD) has gained interest for pre-clinical ex-vivo alpha particle imaging. We present a simulation-based analysis of the fundamental spatial resolution limits of digital autoradiography systems. Spatial resolution was quantified in terms of the modulation transfer function (MTF) and Wagner's equivalent aperture. We modeled systems operating in either particle-counting (PC) or energy-integrating (EI) mode using a cascaded systems approach that accounts for: 1) the stopping power of alpha particles; 2) the distance alpha particles travel within the scintillator; 3) optical blur, and; 4) binning in detector elements. We applied our analysis to imaging of astatine-211 using an LYSO scintillator with thickness ranging from 10 μm to 20 μm. Our analysis demonstrates that when these systems are operated in particle-counting mode with a centroid-calculation algorithm, the effective apertures of 35 μm can be achieved, which suggests that digital autoradiography may enable quantifying the uptake of alpha emitters in tumors consisting of a few cancer cells. Future work will investigate the image noise and energy-resolution properties of digital autoradiography systems.

Spectral reflectance properties of electroplated and converted zinc for use as a solar selective coating

NASA Technical Reports Server (NTRS)

Mcdonald, G. E.; Curtis, H. B.; Gianelos, L.

1975-01-01

The spectral reflectance properties of electroplated and chemically converted zinc were measured for both chromate and chloride conversion coatings. The reflectance properties were measured for various times of conversion and for conversion at various chromate concentrations. The values of absorptance, alpha, integrated over the solar spectrum, and of infrared emittance, epsilon, integrated over black body radiation at 250 F were then calculated from the measured reflectance values. The interdependent variations of alpha and epsilon were plotted. The results indicate that the optimum combination of the highest absorptance in the solar spectrum and the lowest emittance in the infrared of the converted electroplated zinc is produced by chromate conversion at 1/2 concentration of the standard NEOSTAR chromate black solution for 0.50 minute or by chloride conversion for 0.50 minute.

Development and Testing of a 212Pb/212Bi Peptide for Targeting Metastatic Melanoma

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

Fisher, Darrell R.

2012-10-25

The purpose of this project is to develop a new radiolabeled peptide for imaging and treating metastatic melanoma. The immunoconjugate consists of a receptor-specific peptide that targets melanoma cells. The beta-emitter lead-212 (half-life = 10.4 hours) is linked by coordination chemistry to the peptide. After injection, the peptide targets melanoma receptors on the surfaces of melanoma cells. Lead-212 decays to the alpha-emitter bismuth-212 (half-life = 60 minutes). Alpha-particles that hit melanoma cell nuclei are likely to kill the melanoma cell. For cancer cell imaging, the lead-212 is replaced by lead-203 (half-life = 52 hours). Lead-203 emits 279 keV photons (80.1%more » abundance) that can be imaged and measured for biodistribution analysis, cancer imaging, and quantitative dosimetry.« less

Prototype Demonstration of Gamma- Blind Tensioned Metastable Fluid Neutron/Multiplicity/Alpha Detector – Real Time Methods for Advanced Fuel Cycle Applications

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

McDeavitt, Sean M.

The content of this report summarizes a multi-year effort to develop prototype detection equipment using the Tensioned Metastable Fluid Detector (TMFD) technology developed by Taleyarkhan [1]. The context of this development effort was to create new methods for evaluating and developing advanced methods for safeguarding nuclear materials along with instrumentation in various stages of the fuel cycle, especially in material balance areas (MBAs) and during reprocessing of used nuclear fuel. One of the challenges related to the implementation of any type of MBA and/or reprocessing technology (e.g., PUREX or UREX) is the real-time quantification and control of the transuranic (TRU)more » isotopes as they move through the process. Monitoring of higher actinides from their neutron emission (including multiplicity) and alpha signatures during transit in MBAs and in aqueous separations is a critical research area. By providing on-line real-time materials accountability, diversion of the materials becomes much more difficult. The Tensioned Metastable Fluid Detector (TMFD) is a transformational technology that is uniquely capable of both alpha and neutron spectroscopy while being “blind” to the intense gamma field that typically accompanies used fuel – simultaneously with the ability to provide multiplicity information as well [1-3]. The TMFD technology was proven (lab-scale) as part of a 2008 NERI-C program [1-7]. The bulk of this report describes the advancements and demonstrations made in TMFD technology. One final point to present before turning to the TMFD demonstrations is the context for discussing real-time monitoring of SNM. It is useful to review the spectrum of isotopes generated within nuclear fuel during reactor operations. Used nuclear fuel (UNF) from a light water reactor (LWR) contains fission products as well as TRU elements formed through neutron absorption/decay chains. The majority of the fission products are gamma and beta emitters and they represent the more significant hazards from a radiation protection standpoint. However, alpha and neutron emitting uranium and TRU elements represent the more significant safeguards and security concerns. Table 1.1 presents a representative PWR inventory of the uranium and actinide isotopes present in a used fuel assembly. The uranium and actinide isotopes (chiefly the Pu, Am and Cm elements) are all emitters of alpha particles and some of them release significant quantities of neutrons through spontaneous fissions« less

Role of constant value of surface diffuseness in alpha decay half-lives of superheavy nuclei

NASA Astrophysics Data System (ADS)

Dehghani, V.; Alavi, S. A.; Benam, Kh.

2018-05-01

By using WKB method and considering deformed Woods-Saxon nuclear potential, deformed Coulomb potential, and centrifugal potential, the alpha decay half-lives of 68 superheavy alpha emitters have been calculated. The effect of the constant value of surface diffuseness parameter in the range of 0.1 ≤ a ≤ 0.9 (fm) on the potential barrier, tunneling probability, assault frequency, and alpha decay half-lives has been investigated. Significant differences were observed for alpha decay half-lives and decay quantities in this range of surface diffuseness. Good agreement between calculated half-lives with fitted surface diffuseness parameter a = 0.54 (fm) and experiment was observed.

Evaluation of the use of reverse osmosis to eliminate natural radionuclides from water samples.

PubMed

Nieto, Antonio; Palomo, Marta; Ruana, Josep; Peñalver, Alejandra; Aguilar, Carme; Borrull, Francesc

2013-12-01

The objective of drinking water treatment plants (DWTP) is to supply the population with tap water that is in optimal condition and in compliance with water quality regulations. In the DWTP of L'Ampolla (Tarragona, Spain), slightly high values of gross alpha activity and the amount of salts in the raw water have been observed. Conventional treatment has reduced these levels only minimally. This study tested a tertiary treatment based on reverse osmosis is tested in an industrial pilot plant (240 m3/day) The efficiency of this pilot plant to reduce the gross alpha and beta activities and the activity of some individual radioisotopes (U(238), U(234), U(235) and Ra(226)) was tested. Results showed that the elimination of alpha emitters was greater than 90%, whereas the elimination of beta emitters was about 35%. Overall, the data provided evidence that the pilot plant is effective for removing different radionuclides that can be present in the incoming water treated. Therefore, tertiary treatment based on reverse osmosis has a positive effect in water quality.

Adaptation and impairment of DNA repair function in pollen of Betula verrucosa and seeds of Oenothera biennis from differently radionuclide-contaminated sites of Chernobyl.

PubMed

Boubriak, I I; Grodzinsky, D M; Polischuk, V P; Naumenko, V D; Gushcha, N P; Micheev, A N; McCready, S J; Osborne, D J

2008-01-01

The plants that have remained in the contaminated areas around Chernobyl since 1986 encapsulate the effects of radiation. Such plants are chronically exposed to radionuclides that they have accumulated internally as well as to alpha-, beta- and gamma-emitting radionuclides from external sources and from the soil. This radiation leads to genetic damage that can be countered by DNA repair systems. The objective of this study is to follow DNA repair and adaptation in haploid cells (birch pollen) and diploid cells (seed embryos of the evening primrose) from plants that have been growing in situ in different radionuclide fall-out sites in monitored regions surrounding the Chernobyl explosion of 1986. Radionuclide levels in soil were detected using gamma-spectroscopy and radiochemistry. DNA repair assays included measurement of unscheduled DNA synthesis, electrophoretic determination of single-strand DNA breaks and image analysis of rDNA repeats after repair intervals. Nucleosome levels were established using an ELISA kit. Birch pollen collected in 1987 failed to perform unscheduled DNA synthesis, but pollen at gamma/beta-emitter sites has now recovered this ability. At a site with high levels of combined alpha- and gamma/beta-emitters, pollen still exhibits hidden damage, as shown by reduced unscheduled DNA synthesis and failure to repair lesions in rDNA repeats properly. Evening primrose seed embryos generated on plants at the same gamma/beta-emitter sites now show an improved DNA repair capacity and ability to germinate under abiotic stresses (salinity and accelerated ageing). Again those from combined alpha- and gamma/beta-contaminated site do not show this improvement. Chronic irradiation at gamma/beta-emitter sites has provided opportunities for plant cells (both pollen and embryo cells) to adapt to ionizing irradiation and other environmental stresses. This may be explained by facilitation of DNA repair function.

Final Report for DUSEL R&D: BetaCage: A Screener of Ultra-Low-Level Radioactive Surface Contamination

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

Golwala, Sunil R.

2013-12-20

The eventual full-size, radiopure BetaCage will be a low-background, atmospheric-pressure neon drift chamber with unprecedented sensitivity to emitters of low-energy electrons and alpha particles. We expect that the prototype BetaCage already developed will be an excellent screener of alpha particles. Both the prototype and final BetaCage will provide new infrastructure for rare-event science.

GAS MOTION STUDY OF Ly{alpha} EMITTERS AT z {approx} 2 USING FUV AND OPTICAL SPECTRAL LINES {sup ,}

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

Hashimoto, Takuya; Shimasaku, Kazuhiro; Nakajima, Kimihiko

2013-03-01

We present the results of Magellan/MMIRS and Keck/NIRSPEC spectroscopy for five Ly{alpha} emitters (LAEs) at z {approx_equal} 2.2 for which high-resolution FUV spectra from Magellan/MagE are available. We detect nebular emission lines including H{alpha} on the individual basis and low-ionization interstellar (LIS) absorption lines in a stacked FUV spectrum, and measure average offset velocities of the Ly{alpha} line, {Delta}v {sub Ly{alpha}}, and LIS absorption lines, {Delta}v {sub abs}, with respect to the systemic velocity defined by the nebular lines. For a sample of eight z {approx} 2-3 LAEs without active galactic nucleus from our study and the literature, we obtainmore » {Delta}v {sub Ly{alpha}} = 175 {+-} 35 km s{sup -1}, which is significantly smaller than that of Lyman-break Galaxies (LBGs), {Delta}v {sub Ly{alpha}} {approx_equal} 400 km s{sup -1}. The stacked FUV spectrum gives {Delta}v {sub abs} = -179 {+-} 73 km s{sup -1}, comparable to that of LBGs. These positive {Delta}v {sub Ly{alpha}} and negative {Delta}v {sub abs} suggest that LAEs also have outflows. In contrast to LBGs, however, the LAEs' {Delta}v {sub Ly{alpha}} is as small as |{Delta}v {sub abs}|, suggesting low neutral hydrogen column densities. Such a low column density with a small number of resonant scattering may cause the observed strong Ly{alpha} emission of LAEs. We find an anti-correlation between Ly{alpha} equivalent width (EW) and {Delta}v {sub Ly{alpha}} in a compilation of LAE and LBG samples. Although its physical origin is not clear, this anti-correlation result appears to challenge the hypothesis that a strong outflow, by means of a reduced number of resonant scattering, produces a large EW. If LAEs at z > 6 have similarly small {Delta}v {sub Ly{alpha}} values, constraints on the reionization history derived from the Ly{alpha} transmissivity may need to be revised.« less

Alpha-SNAP functions in insulin exocytosis from mature, but not immature secretory granules in pancreatic beta cells.

PubMed

Nakamichi, Y; Nagamatsu, S

1999-06-24

To explore alpha-SNAP function in insulin exocytosis from either immature or mature secretory granules in pancreatic beta cells, we studied the effects of overexpression of adenovirus-mediated wild-type alpha-SNAP and C-terminally deleted alpha-SNAP mutant (1-285) on newly synthesized proinsulin and insulin release by rat islets and MIN6 cells. Rat islets overexpressing alpha-SNAP and mutant alpha-SNAP were pulse-chased. Exocytosis from immature and mature insulin secretory granules was measured as fractional (%) labeled-proinsulin release immediately after the pulse-labeling and percentage labeled-insulin release after a 3-h chase period, respectively. There was no difference in percentage labeled-proinsulin release between the control and alpha-SNAP or mutant alpha-SNAP-overexpressed islets. Although percentage labeled-insulin release after a 3-h chase period was significantly increased in alpha-SNAP-overexpressed islets, it was decreased in mutant alpha-SNAP-overexpressed islets. Thus, the results demonstrated that alpha-SNAP overexpression in rat islets primarily increased exocytosis from mature, but not immature insulin secretory granules. On the other hand, in MIN6 cells, alpha-SNAP overexpression scarcely affected glucose-stimulated insulin release; therefore, we examined the effect of mutant alpha-SNAP overexpression as the dominant-negative inhibitor on the newly synthesized proinsulin/insulin release using the same protocol as in the rat islet experiments. alpha-SNAP mutant (1-285) overexpression in MIN6 cells decreased the percentage labeled insulin release from mature secretory granules, but not percentage labeled proinsulin release from immature secretory granules. Thus, our data demonstrate that alpha-SNAP functions mainly in the mature insulin secretory granules in pancreatic beta cells. Copyright 1999 Academic Press.

Design and Development of Emittance Measurement Device by Using the Pepper-pot Technique

NASA Astrophysics Data System (ADS)

Pakluea, S.; Rimjaem, S.

2017-09-01

Transverse emittance of a charged particle beam is one of the most important properties that reveals the quality of the beam. It is related to charge density, transvers size and angular displacement of the beam in transverse phase space. There are several techniques to measure the transverse emittance value. One of practical methods is the pepper-pot technique, which can measure both horizontal and vertical emittance value in a single measurement. This research concentrates on development of a pepper-pot device to measure the transverse emittance of electron beam produced from an accelerator injector system, which consists of a thermionic cathode RF electron gun and an alpha magnet, at the Plasma and Beam Physics Research Facility, Chiang Mai University. Simulation of beam dynamics was conducted with programs PARMELA, ELEGANT and self-developed codes using C and MATLAB. The geometry, dimensions and location of the pepper-pot as well as its corresponding screen station position were included in the simulation. The result from this study will be used to design and develop a practical pepper-pot experimental station.

[Low level alpha activity measurements with pulse shape discrimination--application to the determination of alpha-nuclides in environmental samples].

PubMed

Satoh, K; Noguchi, M; Higuchi, H; Kitamura, K

1984-12-01

Liquid scintillation counting of alpha rays with pulse shape discrimination was applied to the analysis of 226Ra and 239+240Pu in environmental samples and of alpha-emitters in/on a filter paper. The instrument used in this study was either a specially designed detector or a commercial liquid scintillation counter with an automatic sample changer, both of which were connected to the pulse shape discrimination circuit. The background counting rate in alpha energy region of 5-7 MeV was 0.01 or 0.04 cpm/MeV, respectively. The figure of merit indicating the resolving power for alpha- and beta-particles in time spectrum was found to be 5.7 for the commercial liquid scintillation counter.

Trimethyltin-activated cyclooxygenase stimulates tumor necrosis factor-alpha release from glial cells through reactive oxygen species.

PubMed

Viviani, B; Corsini, E; Pesenti, M; Galli, C L; Marinovich, M

2001-04-15

Exposure of a primary culture of glial cells to the classical neurotoxicant trimethyltin (TMT) results in the release of prostaglandin (PG)E(2) and tumor necrosis factor (TNF)-alpha. Prior treatment of glial cells with either the nonspecific inhibitor of cyclooxygenase and lypoxygenase eicosatetraynoic acid (ETYA) or the cyclooxygenase inhibitor indomethacin completely prevented TMT-induced PGE(2) production and TNF-alpha release, suggesting a role for cyclooxygenase metabolites in TMT-induced TNF-alpha release. Exposure of glial cells to increasing concentrations of PGE(2) or other prostanoids did not increase TNF-alpha synthesis, while the presence of exogenous PGE(2) during treatment of glial cells with TMT actually suppressed TNF-alpha release. The activation of arachidonic acid metabolism produces reactive oxygen species (ROS). Scavenging of ROS by means of the antioxidant trolox prevented the TMT-induced release of TNF-alpha from glial cells, while indomethacin was found to suppress ROS formation induced by 1 microM TMT in glial cells. These results suggest that activation of arachidonic acid metabolism causes TNF-alpha release through the production of ROS rather than PGE(2). Indeed, PGE(2) may exert negative feedback on the release of TNF-alpha. Copyright 2001 Academic Press.

Periodic Table of Elements: Los Alamos National Laboratory

Science.gov Websites

during the formation of the Earth (4.5 billion years old) has long since decayed away by now. However ) neutrons. Neptunium-237 is irradiated with neutrons to create 238Pu, an alpha emitter for radioisotope

TNF{alpha} release from peripheral blood leukocytes depends on a CRM1-mediated nuclear export

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

Miskolci, Veronika; Department of Pediatrics, Feinstein Institute for Medical Research at the North Shore-Long Island Jewish Health System, New Hyde Park, NY 11040; Ghosh, Chandra C.

2006-12-15

Tumor necrosis factor-{alpha} (TNF{alpha}) is a potent pro-inflammatory cytokine that plays a major role in the pathogenesis of acute and chronic inflammatory disorders such as septic shock and arthritis, respectively. Leukocytes stimulated with inflammatory signals such as lipopolysaccharide (LPS) are the predominant producers of TNF{alpha}, and thus control of TNF{alpha} release from stimulated leukocytes represents a potential therapeutic target. Here, we report that leptomycin B (LMB), a specific inhibitor of CRM1-dependent nuclear protein export, inhibits TNF{alpha} release from LPS-stimulated human peripheral blood neutrophils and mononuclear cells. In addition, immunofluorescence confocal microscopy and immunoblotting analysis indicate that TNF{alpha} is localized inmore » the nucleus of human neutrophils and mononuclear cells. This study demonstrates that the cellular release of TNF{alpha} from stimulated leukocytes is mediated by the CRM1-dependent nuclear export mechanism. Inhibition of CRM1-dependent cellular release of TNF{alpha} could thus provide a novel therapeutic approach for disorders involving excessive TNF{alpha} release.« less

KECK SPECTROSCOPY OF FAINT 3 < z < 8 LYMAN BREAK GALAXIES: EVIDENCE FOR A DECLINING FRACTION OF EMISSION LINE SOURCES IN THE REDSHIFT RANGE 6 < z < 8

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

Schenker, Matthew A.; Ellis, Richard S.; Robertson, Brant E.

2012-01-10

Using deep Keck spectroscopy of Lyman break galaxies selected from infrared imaging data taken with the Wide Field Camera 3 on board the Hubble Space Telescope, we present new evidence for a reversal in the redshift-dependent fraction of star-forming galaxies with detectable Lyman alpha (Ly{alpha}) emission in the redshift range 6.3 < z < 8.8. Our earlier surveys with the DEIMOS spectrograph demonstrated a significant increase with redshift in the fraction of line emitting galaxies over the interval 4 < z < 6, particularly for intrinsically faint systems which dominate the luminosity density. Using the longer wavelength sensitivities of Lowmore » Resolution Imaging Spectrometer and NIRSPEC, we have targeted 19 Lyman break galaxies selected using recent WFC3/IR data whose photometric redshifts are in the range 6.3 < z < 8.8 and which span a wide range of intrinsic luminosities. Our spectroscopic exposures typically reach a 5{sigma} sensitivity of <50 A for the rest-frame equivalent width (EW) of Ly{alpha} emission. Despite the high fraction of emitters seen only a few hundred million years later, we find only two convincing and one possible line emitter in our more distant sample. Combining with published data on a further seven sources obtained using FORS2 on the ESO Very Large Telescope, and assuming continuity in the trends found at lower redshift, we discuss the significance of this apparent reversal in the redshift-dependent Ly{alpha} fraction in the context of our range in continuum luminosity. Assuming all the targeted sources are at their photometric redshift and our assumptions about the Ly{alpha} EW distribution are correct, we would expect to find so few emitters in less than 1% of the realizations drawn from our lower redshift samples. Our new results provide further support for the suggestion that, at the redshifts now being probed spectroscopically, we are entering the era where the intergalactic medium is partially neutral. With the arrival of more sensitive multi-slit infrared spectrographs, the prospects for improving the statistical validity of this result are promising.« less

DEEP LBT/LUCI SPECTROSCOPY OF AN Ly{alpha} EMITTER CANDIDATE AT z {approx_equal} 7.7

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

Jiang Linhua; Bian Fuyan; Fan Xiaohui

2013-07-01

We present deep spectroscopic observations of an Ly{alpha} emitter (LAE) candidate at z {approx_equal} 7.7 using the infrared spectrograph LUCI on the 2 Multiplication-Sign 8.4 m Large Binocular Telescope (LBT). The candidate is the brightest among the four z {approx_equal} 7.7 LAE candidates found in a narrowband imaging survey by Krug et al. Our spectroscopic data include a total of 7.5 hr of integration with LBT/LUCI and are deep enough to significantly (3.2{sigma}-4.9{sigma}) detect the Ly{alpha} emission line of this candidate based on its Ly{alpha} flux 1.2 Multiplication-Sign 10{sup -17} erg s{sup -1} cm{sup -2} estimated from the narrowband photometry.more » However, we do not find any convincing signal at the expected position of its Ly{alpha} emission line, suggesting that this source is not an LAE at z {approx_equal} 7.7. The non-detection in this work, together with the previous studies of z {approx_equal} 7.7 LAEs, puts a strong constraint on the bright-end Ly{alpha} luminosity function (LF) at z {approx_equal} 7.7. We find a rapid evolution of the Ly{alpha} LF from z {approx_equal} 6.5 to 7.7: the upper limit of the z {approx_equal} 7.7 LF is more than five times lower than the z {approx_equal} 6.5 LF at the bright end (f{>=} 1.0 Multiplication-Sign 10{sup -17} erg s{sup -1} cm{sup -2} or L{>=} 6.9 Multiplication-Sign 10{sup 42} erg s{sup -1}). This is likely caused by an increasing neutral fraction in the intergalactic medium that substantially attenuates Ly{alpha} emission at z {approx_equal} 7.7.« less

Treatment of carcinoma in situ of the urinary bladder with an alpha-emitter immunoconjugate targeting the epidermal growth factor receptor: a pilot study.

PubMed

Autenrieth, Michael E; Seidl, Christof; Bruchertseifer, Frank; Horn, Thomas; Kurtz, Florian; Feuerecker, Benedikt; D'Alessandria, Calogero; Pfob, Christian; Nekolla, Stephan; Apostolidis, Christos; Mirzadeh, Saed; Gschwend, Jürgen E; Schwaiger, Markus; Scheidhauer, Klemens; Morgenstern, Alfred

2018-07-01

Patients with carcinoma in situ (CIS) of the bladder refractory to bacillus Calmette-Guérin (BCG) treatment are usually treated with cystectomy. Therefore, new treatment options with preservation of the urinary bladder are needed. The objective of the study was to investigate the feasibility, safety and efficacy of a novel targeted alpha-emitter immunotherapy for CIS after BCG treatment failure. A pilot study was conducted in 12 patients (age range 64-86 years, ten men, two women) with biopsy-proven CIS of the bladder refractory to BCG treatment. The patients were treated intravesically with a single instillation (one patient was treated twice) of the alpha-emitter 213 Bi coupled to an anti-EGFR antibody (366-821 MBq). The primary aims of the study were to determine the feasibility of treatment with the 213 Bi-immunoconjugate and evaluation of adverse effects. Therapeutic efficacy was monitored by histological mapping of the urinary bladder 8 weeks after treatment and at different time points thereafter. The study proved that intravesical instillation of the 213 Bi-immunoconjugate targeting EGFR is feasible. No adverse effects were observed and all blood and urine parameters determined remained in their normal ranges. Therapeutic efficacy was considered satisfactory, in that three of the 12 patients showed no signs of CIS 44, 30 and 3 months after treatment. Intravesical instillation of 213 Bi-anti-EGFR monoclonal antibody was well tolerated and showed therapeutic efficacy. Repeated instillation and/or instillation of higher activities of the 213 Bi-immunoconjugate might lead to better therapeutic outcomes. A phase I clinical trial is planned.

223Ra-dichloride spectrometric characterization: Searching for the presence of long-lived isotopes with radiological protection implications.

PubMed

Sánchez-Jiménez, J; López-Montes, A; Núñez-Martínez, L; Villa-Abaunza, A; Fraile, L M; Sánchez-Tembleque, V; Udías, J M

2017-03-01

223 Ra-dichloride was approved with the commercial name of Xofigo in 2014 for treatment of metastatic castration-resistant prostate cancer. 223 Ra is obtained by neutron irradiation of 226 Ra yielding 227 Ac, which decays to 227 Th and 223 Fr, both decaying to 223 Ra. Since 223 Ra is predominantly (95.3%) an alpha emitter with a 11.42days long half-life, the radiopharmaceutical, its remnants, the patient, and waste material can be managed and disposed with low radiation protection requirements. 227 Ac is a long-lived (T 1/2 =21.77years) beta emitter that demands strong radiation protection measures. In particular waste disposal has to follow the International Atomic Energy Agency (IAEA) and European Commission (EC) regulations. Since 227 Ac is involved in the production of 223 Ra, an impurity analysis of each batch is required after production. Due to time restrictions, the manufacturer's detection limit (<0.001%) exceeds the one required to assure that 227 Ac concentrations are below direct disposal levels. To improve the detection limit, long-term accurate spectroscopy is required. Alpha and gamma spectroscopy measurements were carried out at the Complutense University Nuclear Physics Laboratory. After twelve months follow up of a sample, 227 Ac concentration was found to be smaller than 10 -9 . This allows for direct waste disposal and no additional radiation protection restrictions than those required for 223 Ra. The presence of contamination by other radioisotopes was also ruled out by this experiment. Specifically 226 Ra, involved in 223 Ra production as the original parent and with a very long-lived (T 1/2 =1577years) alpha emitter, was also below the experimental detection limit. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Emitters of N-photon bundles

PubMed Central

Muñoz, C. Sánchez; del Valle, E.; Tudela, A. González; Müller, K.; Lichtmannecker, S.; Kaniber, M.; Tejedor, C.; Finley, J.J.; Laussy, F.P.

2014-01-01

Controlling the ouput of a light emitter is one of the basic tasks of photonics, with landmarks such as the laser and single-photon sources. The development of quantum applications makes it increasingly important to diversify the available quantum sources. Here, we propose a cavity QED scheme to realize emitters that release their energy in groups, or “bundles” of N photons, for integer N. Close to 100% of two-photon emission and 90% of three-photon emission is shown to be within reach of state of the art samples. The emission can be tuned with system parameters so that the device behaves as a laser or as a N-photon gun. The theoretical formalism to characterize such emitters is developed, with the bundle statistics arising as an extension of the fundamental correlation functions of quantum optics. These emitters will be useful for quantum information processing and for medical applications. PMID:25013456

Effect of metallic iron on the oxidative dissolution of UO2 doped with a radioactive alpha emitter in synthetic Callovian-Oxfordian groundwater

NASA Astrophysics Data System (ADS)

Odorowski, Mélina; Jegou, Christophe; De Windt, Laurent; Broudic, Véronique; Jouan, Gauthier; Peuget, Sylvain; Martin, Christelle

2017-12-01

In the hypothesis of direct disposal of spent fuel in a geological nuclear waste repository, interactions between the fuel mainly composed of UO2 and its environment must be understood. The dissolution rate of the UO2 matrix, which depends on the redox conditions on the fuel surface, will have a major impact on the release of radionuclides into the environment. The reducing conditions expected for a geological disposal situation would appear to be favorable as regards the solubility and stability of the UO2 matrix, but may be disturbed on the surface of irradiated fuel. In particular, the local redox conditions will result from a competition between the radiolysis effects of water under alpha irradiation (simultaneously producing oxidizing species like H2O2, hydrogen peroxide, and reducing species like H2, hydrogen) and those of redox active species from the environment. In particular, Fe2+, a strongly reducing aqueous species coming from the corrosion of the iron canister or from the host rock, could influence the dissolution of the fuel matrix. The effect of iron on the oxidative dissolution of UO2 was thus investigated under the conditions of the French disposal site, a Callovian-Oxfordian clay formation chosen by the French National Radioactive Waste Management Agency (Andra), here tested under alpha irradiation. For this study, UO2 fuel pellets doped with a radioactive alpha emitter (238/239Pu) were leached in synthetic Callovian-Oxfordian groundwater (representative of the French waste disposal site groundwater) in the presence of a metallic iron foil to simulate the steel canister. The pellets had varying levels of alpha activity, in order to modulate the concentrations of species produced by water radiolysis on the surface and to simulate the activity of aged spent fuel after 50 and 10,000 years of alpha radioactivity decay. The experimental data showed that whatever the sample alpha radioactivity, the presence of iron inhibits the oxidizing dissolution of UO2 and leads to low uranium concentrations (between 4 × 10-10 and 4 × 10-9 M), through a reactional mechanism located in the very first microns of the UO2/water reactional interface. The mechanism involves consumption of oxidizing species, in particular of H2O2 by Fe2+ at the precise place where these species are produced, and is accompanied by the precipitation of an akaganeite-type Fe3+ hydroxide on the surface. The higher the radioactivity of the samples, the greater the precipitation induced. Modeling has been developed, coupling chemistry with transport and based on the main reactional mechanisms identified, which enables accurate reproduction of the mineralogy of the system under study, giving the nature of the phases under observation as well as the location of their precipitation. Obviously without excluding a potential contribution from the hydrogen produced by the anoxic corrosion of the iron foil, this study has shown that iron plays a major role in this oxidizing dissolution inhibition process for the system investigated (localized alpha radiolysis). This inhibitor effect associated with iron is therefore strongly dependent on the location of the redox front, which is found on the surface in the case of alpha irradiation UO2/water reactional interface.

A method for the assessment of specific energy distribution in a model tumor system

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

Noska, M.A.

1996-12-31

Due to the short range of alpha particles in tissue, the calculation of dose from internally deposited alpha emitters requires a detailed analysis of the microscopic distribution of the radionuclide in order to determine the spatial distribution of energy emission events and, from this, the spatial distribution of dose. In the present study, the authors used quantitative autoradiography (QAR) to assess the microdistribution of a radiolabeled monoclonal antibody (MAb) fragment in human glioma xenografts in mice.

Novel sustained-release dosage forms of proteins using polyglycerol esters of fatty acids.

PubMed

Yamagata, Y; Iga, K; Ogawa, Y

2000-02-03

In order to develop a novel delivery system for proteins based on polyglycerol esters of fatty acids (PGEFs), we studied a model system using interferon-alpha (IFN-alpha) as the test protein. A cylindrical matrix was prepared by a heat extrusion technique using a lyophilized powder of the protein and 11 different types of synthetic PGEFs, which varied in degree of glycerol polymerization (di- and tetra-), chain length of fatty acids (myristate, palmitate and stearate) and degree of fatty acid esterification (mono-, di- and tri-). In an in-vitro release study using an enzyme-linked immunosorbent assay (ELISA) as a detection method, the matrices prepared from a monoglyceride (used for comparison) and from diglycerol esters exhibited a biphasic release pattern with a large initial burst followed by slow release. In contrast, the matrices prepared from tetraglycerol esters showed a steady rate of release without a large initial burst. In an in vivo release study, initial bursts of IFN-alpha release were, also, dramatically reduced when the matrices were prepared from the tetraglycerol esters of palmitate and stearate, and the mean residence time (MRT) of IFN-alpha was prolonged, whereas the matrices prepared from monoglyceride and from diglycerol esters showed large initial bursts of IFN-alpha release. Since the release rates from the matrices prepared from the tetraglycerol esters of palmitate and stearate were governed by Jander's equation modified for a cylindrical matrix, the release from those matrices was concluded to be a diffusion-controlled process. The bioavailability of IFN-alpha after implantation of the matrix formulation prepared using all types of PGEFs, except for tetraglycerol triesters, was almost equivalent to that after injection of IFN-alpha solution; consequently, IFN-alpha in these matrices appears to remain stable during the release period.

Performances of the Alpha-X RF gun on the PHIL accelerator at LAL

NASA Astrophysics Data System (ADS)

Vinatier, T.; Bruni, C.; Roux, R.; Brossard, J.; Chancé, S.; Cayla, J. N.; Chaumat, V.; Xu, G.; Monard, H.

2015-10-01

The Alpha-X RF-gun was designed to produce an ultra-short (<100 fs rms), 100 pC and 6.3 MeV electron beam with a normalized rms transverse emittance of 1π mm mrad for a gun peak accelerating field of 100 MV/m. Such beams will be required by the Alpha-X project, which aims to study a laser-driven plasma accelerator with a short wavelength accelerating medium. It has been demonstrated on PHIL (Photo-Injector at LAL) that the coaxial RF coupling, chosen to preserve the gun field cylindrical symmetry, is perfectly understood and allows reaching the required peak accelerating field of 100 MV/m giving beam energy of 6.3 MeV. Moreover, a quite low beam rms relative energy spread of 0.15% at 3.8 MeV has been measured, completely agreeing with simulations. Dark current, quantum efficiencies and dephasing curves measurements have also been performed. They all show high values of the field enhancement factor β, which can be explained by the preparation of the photocathodes. Finally, measurements on the transverse phase-space have been carried out, with some limitations given by the difficult modelization of one of the PHIL solenoid magnets and by the enlargement of the beam transverse dimensions due to the use of YAG screens. These measurements give a normalized rms transverse emittance around 5π mm mrad, which does not fulfill the requirement for the Alpha-X project.

Oxidation and emittance of superalloys in heat shield applications

NASA Technical Reports Server (NTRS)

Wiedemann, K. E.; Clark, R. K.; Unnam, J.

1986-01-01

Recently developed superalloys that form alumina coatings have a high potential for heat shield applications for advanced aerospace vehicles at temperatures above 1095C. Both INCOLOY alloy MA 956 (of the Inco Alloys International, Inc.), an iron-base oxide-dispersion-strengthened alloy, and CABOT alloy No. 214 (of the Cabot Corporation), an alumina-forming nickel-chromium alloy, have good oxidation resistance and good elevated temperature strength. The oxidation resistance of both alloys has been attributed to the formation of a thin alumina layer (alpha-Al2O3) at the surface. Emittance and oxidation data were obtained for simulated Space Shuttle reentry conditions using a hypersonic arc-heated wind tunnel. The surface oxides and substrate alloys were characterized using X-ray diffraction and scanning and transmission electron microscopy with an energy-dispersive X-ray analysis unit. The mass loss and emittance characteristics of the two alloys are discussed.

Bioactive interleukin-1alpha is cytolytically released from Candida albicans-infected oral epithelial cells.

PubMed

Dongari-Bagtzoglou, A; Kashleva, H; Villar, C Cunha

2004-12-01

Oral epithelial cells are primary targets of Candida albicans in the oropharynx and may regulate the inflammatory host response to this pathogen. This investigation studied the mechanisms underlying interleukin-1alpha (IL-1alpha) release by oral epithelial cells and the role of IL-1alpha in regulating the mucosal inflammatory response to C. albicans. Infected oral epithelial cells released processed IL-1alpha protein in culture supernatants. The IL-1alpha generated was stored intracellularly and was released upon cell lysis. This was further supported by the fact that different C. albicans strains induced variable IL-1alpha release, depending on their cytolytic activity. IL-1alpha from C. albicans-infected oral epithelial cells upregulated proinflammatory cytokine secretion (IL-8 and GM-CSF) in uninfected oral epithelial or stromal cells. Our studies suggest that production of IL-1alpha, IL-8 and GM-CSF may take place in the oral mucosa in response to lytic infection of epithelial cells with C. albicans. This process can act as an early innate immune surveillance system and may contribute to the clinicopathologic signs of infection in the oral mucosa.

Measuring the Stellar Populations of Individual Lyman Alpha Emitters During the Epoch of Peak Star Formation

NASA Astrophysics Data System (ADS)

Reddy, Naveen

2010-09-01

Selecting galaxies by their strong Lyman-alpha emission provides a powerful means of probing the reionization epoch and the faint/low-mass galaxies that dominate star formation at high redshift. Yet, our understanding of high-redshift Lyman-alpha emitters {LAEs} has lagged behind that of other well-studied populations {e.g., Lyman break galaxies} due to their continuum faintness and the shifting of age/mass-sensitive features into the near-IR where the high terrestrial background inhibits deep observations. All existing studies of LAEs at z>2 have used stacked optical and/or Spitzer infrared data to discern their median properties, but the actual distributions of ages, reddenings, and stellar masses for these populations are poorly characterized. To fill this glaring gap in the observations and advance our understanding of this important population, we propose WFC3/IR+F160W imaging of fields where we have conducted a survey of low redshift {z 1.9} Lyman-alpha emitters {LAEs}, in order to measure their ages and stellar masses at an epoch where such observations directly probe the age-sensitive Balmer/4000 AA breaks. The targeted sample will include 45-50 spectroscopically confirmed LAEs at z=1.7-2.1 and roughly twice as many candidates, making it the largest sample of homogeneously selected LAEs with individual measurements of the ages, masses, and dust extinction. With these data we will {1} carefully take into account the age-dependence of the extinction curve to make robust comparisons between LAEs and continuum-selected galaxies at the same redshifts; {2} combine clustering and stellar mass measurements to infer the duty cycles of LAEs and determine if they are triggered in the presence of large-scale structures; and {3} quantify the importance of the LAE phase at different galaxy luminosity and mass scales, over a large dynamic range in these properties. An economical investment of just 12 orbits will allow us to accomplish these goals, and remains the only hope of efficiently studying such low luminosity high-redshift galaxies in the near-IR prior to the JWST-era.

Prostaglandin F2 alpha and its analogs induce release of endogenous prostaglandins in iris and ciliary muscles isolated from cat and other mammalian species.

PubMed

Yousufzai, S Y; Ye, Z; Abdel-Latif, A A

1996-09-01

Prostaglandin F2 alpha (PGF 2 alpha) and its analog latanoprost are effective in lowering intraocular pressure (IOP) in both animal and human subjects. There is mounting experimental evidence now which indicates that the IOP-lowering effect of these PGs occurs through an increased uveoscleral outflow of aqueous humor. The ciliary muscle constitutes the main resistance in this pathway. Work from several laboratories, including our own, has shown that in this smooth muscle PGF 2 alpha has little effect on cAMP accumulation or on Ca2+ mobilization. In the present study, we hypothesized that some of the effects of PGF2 alpha and its analogs may be mediated through the release of endogenous PGs. The purpose of this work was to determine whether or not PGF2 alpha and its analogs can enhance the release of endogenous PGs in iris and ciliary muscles isolated from different species. This report documents for the first time that exogenous PGF2 alpha and its analogs, PhXA85 and latanoprost, stimulate the formation of PGE2, PGD2 and PGF2 alpha in iris and ciliary muscles isolated from cat, bovine, rabbit, dog, rhesus monkey and human. PG-induced PG release was demonstrated by means of both radioimmunoassay and radiochromatography. Kinetic studies on cat iris revealed that PGF2 alpha-induced PGE2 release is time (t 1/2 = 1.7 min) and dose-dependent (EC50 = 45 nM). The increase in PGE2 release was blocked by indomethacin (Indo) and by dexamethasone in a dose-dependent manner with IC50 s of 9.2 nM and 2.6 microM, respectively. Furthermore, dexamethasone inhibited arachidonic acid (AA) release, suggesting the involvement of phospholipase A2 in PGF2 alpha-induced PG release. The data presented demonstrate that PGF2 alpha and its analogs interact with the PG receptor to stimulate phospholipase A2 and release AA for PG synthesis. Relaxation of ciliary muscle by PGF2 alpha and its analogs, via release of endogenous PGE2, a potent activator of the adenylate cyclase system, could in part explain how these PGs may increase uveoscleral outflow and consequently lower IOP.

Alpha Decay Potential Barriers and Half-Lives and Analytical Formula Predictions for Superheavy Nuclei

NASA Astrophysics Data System (ADS)

Royer, Guy; Zhang, Hongfei

The α decay potential barriers are determined in the cluster-like shape path within a generalized liquid drop model including the proximity effects between the α particle and the daughter nucleus and adjusted to reproduce the experimental Qα. The α emission half-lives are determined within the WKB penetration probability. Calculations using previously proposed formulae depending only on the mass and charge of the alpha emitter and Qα are also compared with new experimental alpha-decay half-lives. The agreement allows to provide predictions for the α decay half-lives of other still unknown superheavy nuclei using the Qα determined from the 2003 atomic mass evaluation of Audi, Wapstra and Thibault.

Variable anodic thermal control coating

NASA Technical Reports Server (NTRS)

Gilliland, C. S.; Duckett, J. (Inventor)

1983-01-01

A process for providing a thermal control solar stable surface coating for aluminum surfaces adapted to be exposed to solar radiation wherein selected values within the range of 0.10 to 0.72 thermal emittance (epsilon sub tau) and 0.2 to 0.4 solar absorptance (alpha subs) are reproducibly obtained by anodizing the surface area in a chromic acid solution for a selected period of time. The rate voltage and time, along with the parameters of initial epsilon sub tau and alpha subs, temperature of the chromic acid solution, acid concentration of the solution and the material anodized determines the final values of epsilon/tau sub and alpha sub S. 9 Claims, 5 Drawing Figures.

Skeletal dosimetry models for alpha-particles for use in molecular radiotherapy

NASA Astrophysics Data System (ADS)

Watchman, Christopher J.

Molecular radiotherapy is a cancer treatment methodology whereby a radionuclide is combined with a biologically active molecule to preferentially target cancer cells. Alpha-particle emitting radionuclides show significant potential for use in molecular radiotherapy due to the short range of the alpha-particles in tissue and their high rates of energy deposition. Current radiation dosimetry models used to assess alpha emitter dose in the skeleton were developed originally for occupational applications. In medical dosimetry, individual variability in uptake, translocation and other biological factors can result in poor correlation of clinical outcome with marrow dose estimates determined using existing skeletal models. Methods presented in this work were developed in response to the need for dosimetry models which account for these biological and patient-specific factors. Dosimetry models are presented for trabecular bone alpha particle dosimetry as well as a model for cortical bone dosimetry. These radiation transport models are the 3D chord-based infinite spongiosa transport model (3D-CBIST) and the chord-based infinite cortical transport model (CBICT), respectively. Absorbed fraction data for several skeletal tissues for several subjects are presented. Each modeling strategy accounts for biological parameters, such as bone marrow cellularity, not previously incorporated into alpha-particle skeletal dosimetry models used in radiation protection. Using these data a study investigating the variability in alpha-particle absorbed fractions in the human skeleton is also presented. Data is also offered relating skeletal tissue masses in individual bone sites for a range of ages. These data are necessary for dose calculations and have previously only been available as whole body tissue masses. A revised 3D-CBIST model is also presented which allows for changes in endosteum thickness to account for revised target cell location of tissues involved in the radiological induction of bone cancer. In addition, new data are presented on the location of bone-marrow stem cells within the marrow cavities of trabecular bone of the pelvis. All results presented in this work may be applied to occupational exposures, but their greatest utility lies in dose assessments for alpha-emitters in molecular radiotherapy.

Activation of alpha-latrotoxin receptors in neuromuscular synapses leads to a prolonged splash acetylcholine release.

PubMed

Lelyanova, V G; Thomson, D; Ribchester, R R; Tonevitsky, E A; Ushkaryov, Y A

2009-06-01

The mechanisms of acetylcholine release in presynaptic terminals of motoneurons induced by mutant alpha-latrotoxin (LT(N4C)) were analyzed. In contrast to wild-type alpha-latrotoxin that causes both continuous and splash secretion of acetylcholine and necessarity block neuromuscular transmission, LT(N4C) causes only splash release lasting over many hours. Thus, activation of alpha-latrotoxin receptors controls long-lasting enhanced secretion of acetylcholine.

Final Report for grant entitled "Production of Astatine-211 for U.S. Investigators"

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

Wilbur, Daniel Scott

2012-12-12

Alpha-particle emitting radionuclides hold great promise in the therapy of cancer, but few alpha-emitters are available to investigators to evaluate. Of the alpha-emitters that have properties amenable for use in humans, 211At is of particular interest as it does not have alpha-emitting daughter radionuclides. Thus, there is a high interest in having a source of 211At for sale to investigators in the US. Production of 211At is accomplished on a cyclotron using an alpha-particle beam irradiation of bismuth metal. Unfortunately, there are few cyclotrons available that can produce an alpha particle beam for that production. The University of Washington hasmore » a cyclotron, one of three in the U.S., that is currently producing 211At. In the proposed studies, the things necessary for production and shipment of 211At to other investigators will be put into place at UW. Of major importance is the efficient production and isolation of 211At in a form that can be readily used by other investigators. In the studies, production of 211At on the UW cyclotron will be optimized by determining the best beam energy and the highest beam current to maximize 211At production. As it would be very difficult for most investigators to isolate the 211At from the irradiated target, the 211At-isolation process will be optimized and automated to more safely and efficiently obtain the 211At for shipment. Additional tasks to make the 211At available for distribution include obtaining appropriate shipping vials and containers, putting into place the requisite standard operating procedures for Radiation Safety compliance at the levels of 211At activity to be produced / shipped, and working with the Department of Energy, Isotope Development and Production for Research and Applications Program, to take orders, make shipments and be reimbursed for costs of production and shipment.« less

Removal of plutonium and americium from alkaline waste solutions

DOEpatents

Schulz, Wallace W.

1979-01-01

High salt content, alkaline waste solutions containing plutonium and americium are contacted with a sodium titanate compound to effect removal of the plutonium and americium from the alkaline waste solution onto the sodium titanate and provide an effluent having a radiation level of less than 10 nCi per gram alpha emitters.

First In Vivo Evaluation of Liposome-encapsulated 223Ra as a Potential Alpha-particle-emitting Cancer Therapeutic Agent

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

Jonasdottir, Thora J.; Fisher, Darrell R.; Borrebaek, Jorgen

2006-09-13

Liposomes carrying chemotherapeutics have had some success in cancer treatment and may be suitable carriers for therapeutic radionuclides. This study was designed to evaluate the biodistribution of and to estimate the radiation doses from the alpha emitter 223Ra loaded into pegylated liposomes in selected tissues. 223Ra was encapsulated in pegylated liposomal doxorubicin by ionophore-mediated loading. The biodistribution of liposomal 223Ra was compared to free cationic 223Ra in Balb/C mice. We showed that liposomal 223 Ra circulated in the blood with an initial half-time in excess of 24 hours, which agreed well with that reported for liposomal doxorubicin in rodents, whilemore » the blood half-time of cationic 223Ra was considerably less than one hour. When liposomal 223 Ra was catabolized, the released 223Ra was either excreted or taken up in the skeleton. This skeletal uptake increased up to 14 days after treatment, but did not reach the level seen with free 223Ra. Pre-treatment with non-radioactive liposomal doxorubicin 4 days in advance lessened the liver uptake of liposomal 223 Ra. Dose estimates showed that the spleen, followed by bone surfaces, received the highest absorbed doses. Liposomal 223 Ra was relatively stable in vivo and may have potential for radionuclide therapy and combination therapy with chemotherapeutic agents.« less

Bioactive peptides released during of digestion of processed milk

USDA-ARS?s Scientific Manuscript database

Most of the proteins contained in milk consist of alpha-s1-, alpha-s2-, beta- and kappa-casein, and some of the peptides contained in these caseins may impart health benefits. To determine if processing affected release of peptides, samples of raw (R), homogenized (H), homogenized and pasteurized (...

LPS receptor CD14 participates in release of TNF-alpha in RAW 264.7 and peritoneal cells but not in kupffer cells.

PubMed

Lichtman, S N; Wang, J; Lemasters, J J

1998-07-01

Lipopolysaccharide (LPS) is a bacterial polymer that stimulates macrophages to release tumor necrosis factor-alpha (TNF-alpha). In macrophages (RAW 264.7 and peritoneal cells), LPS binds to the CD14 surface receptor as the first step toward signaling. Liver macrophages, Kupffer cells, are the most numerous fixed-tissue macrophage in the body. The presence of CD14 on Kupffer cells and its role in LPS stimulation of TNF-alpha were examined. TNF-alpha release by Kupffer cells after LPS stimulation was the same in the presence and absence of serum. RAW 264.7 and peritoneal cells, which utilize the CD14 receptor, released significantly less TNF-alpha after LPS stimulation in the absence of serum because of the absence of LPS-binding protein. Phosphatidylinositol-phospholipase C treatment, which cleaves the CD14 receptor, decreased LPS-stimulated TNF-alpha release by RAW 264.7 cells but not by Kupffer cells. Deacylated LPS (dLPS) competes with LPS at the CD14 receptor when incubated in a ratio of 100:1 (dLPS/LPS). Such competition blocked LPS-stimulated TNF-alpha release from RAW 264.7 cells but not from Kupffer cells. Western and fluorescence-activated cell sorter analysis directly demonstrated the presence of CD14 on RAW 264.7 cells and murine peritoneal cells but showed only minimal amounts of CD14 in murine Kupffer cells. LPS stimulation did not increase the amount of CD14 detectable on mouse Kupffer cells. CD14 expression is very low in Kupffer cells, and LPS-stimulated TNF-alpha release is independent of CD14 in these cells.

Alpha decay calculations with a new formula

NASA Astrophysics Data System (ADS)

Akrawy, D. T.; Poenaru, D. N.

2017-10-01

A new semi-empirical formula for calculations of α decay half-lives is presented. It was derived from the Royer relationship by introducing new parameters which are fixed by fit to a set of experimental data. We are using three sets: set A with 130 e-e (even-even), 119 e-o (even-odd), 109 o-e, and 96 o-o, set B with 188 e-e, 147 e-o, 131 o-e and 114 o-o, and set C with 136 e-e, 84 e-o, 76 o-e and 48 o-o alpha emitters. A comparison of results obtained with the new formula (newF) and the following well known relationships: semiempirical relationship based on fission theory (semFIS), analytical superasymmetric fission (ASAF) model and universal formula (UNIV) made in terms of rms standard deviation. We also introduced a weighted mean value of this quantity, allowing us to compare the global properties of a given model. For set B the order of the four models is the following: semFIS, UNIV, newF and ASAF. Nevertheless for even-even alpha emitters, UNIV gives the second best result after semFIS, and for odd-even parents the second is newF. Despite its simplicity in comparison with semFIS, newF, presented in this article, behaves quite well, competing with the other well known relationships.

Radioactivity in food crops

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

Drury, J.S.; Baldauf, M.F.; Daniel, E.W.

Published levels of radioactivity in food crops from 21 countries and 4 island chains of Oceania are listed. The tabulation includes more than 3000 examples of 100 different crops. Data are arranged alphabetically by food crop and geographical origin. The sampling date, nuclide measured, mean radioactivity, range of radioactivities, sample basis, number of samples analyzed, and bibliographic citation are given for each entry, when available. Analyses were reported most frequently for /sup 137/Cs, /sup 40/K, /sup 90/Sr, /sup 226/Ra, /sup 228/Ra, plutonium, uranium, total alpha, and total beta, but a few authors also reported data for /sup 241/Am, /sup 7/Be,more » /sup 60/Co, /sup 55/Fe, /sup 3/H, /sup 131/I, /sup 54/Mn, /sup 95/Nb, /sup 210/Pb, /sup 210/Po, /sup 106/Ru, /sup 125/Sb, /sup 228/Th, /sup 232/Th, and /sup 95/Zr. Based on the reported data it appears that radioactivity from alpha emitters in food crops is usually low, on the order of 0.1 Bq.g/sup -1/ (wet weight) or less. Reported values of beta radiation in a given crop generally appear to be several orders of magnitude greater than those of alpha emitters. The most striking aspect of the data is the great range of radioactivity reported for a given nuclide in similar food crops with different geographical origins.« less

alpha7 and non-alpha7 nicotinic acetylcholine receptors modulate dopamine release in vitro and in vivo in the rat prefrontal cortex.

PubMed

Livingstone, Phil D; Srinivasan, Jayaraman; Kew, James N C; Dawson, Lee A; Gotti, Cecilia; Moretti, Milena; Shoaib, Mohammed; Wonnacott, Susan

2009-02-01

Nicotine enhances attentional and working memory aspects of executive function in the prefrontal cortex (PFC) where dopamine plays a major role. Here, we have determined the nicotinic acetylcholine receptor (nAChR) subtypes that can modulate dopamine release in rat PFC using subtype-selective drugs. Nicotine and 5-Iodo-A-85380 (beta2* selective) elicited [(3)H]dopamine release from both PFC and striatal prisms in vitro and dopamine overflow from medial PFC in vivo. Blockade by dihydro-beta-erythroidine supports the participation of beta2* nAChRs. However, insensitivity of nicotine-evoked [(3)H]dopamine release to alpha-conotoxin-MII in PFC prisms suggests no involvement of alpha6beta2* nAChRs, in contrast to the striatum, and this distinction is supported by immunoprecipitation of nAChR subunits from these tissues. The alpha7 nAChR-selective agonists choline and Compound A also promoted dopamine release from PFC in vitro and in vivo, and their effects were enhanced by the alpha7 nAChR-selective allosteric potentiator PNU-120596 and blocked by specific antagonists. DNQX and MK801 inhibited [(3)H]dopamine release evoked by choline and PNU-120596, suggesting crosstalk between alpha7 nAChRs, glutamate and dopamine in the PFC. In vivo, systemic (but not local) administration of PNU-120596, in the absence of agonist, facilitated dopamine overflow in the medial PFC, consistent with the activation of extracortical alpha7 nAChRs by endogenous acetylcholine or choline. These data establish that both beta2* and alpha7 nAChRs can modulate dopamine release in the PFC in vitro and in vivo. Through their distinct actions on dopamine release, these nAChR subtypes could contribute to executive function, making them specific therapeutic targets for conditions such as schizophrenia and attention deficit hyperactivity disorder.

Effect of longitudinal aberration in an ion-optical system on the properties of a focused beam

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

Getmanov, V.N.; Ikryanov, I.M.; Savchenko, O.Ya.

1994-11-01

Modelling of the processes involved in the passage of a beam through a system of high-voltage electrodes with allowance made for the thermal and grid spreads of transverse particle velocities constitutes a three-dimensional problem that is difficult to solve with modern computers. In the present work, an analytic method has been developed that reduces this problem to a two-dimensional one. The method corresponds to approximating a marked longitudinal aberration in an ion-optical system (IOS), when the effective emittance of the beam during its high-voltage shaping increases severalfold, this being characteristic of all IOS know thus far. Fully justified in thismore » case is the statement that a unique relationship exists between the coordinates r and z, which respectively characterize the location of the particle on the emitter and the point of intersection of the axis by the particle (or the point of maximum approach of the particle to the axis), and also between r and {alpha} ({alpha}being the angle between the particle trajectory in the focusing region and the axis of the system). This statement leads to a hyperbolic law of increase in current density in the central portion of the focused beam and thus confirms the validity of this law. The calculations were compared with experimental data on the focusing of a 0.4-MeV proton beam with a current of 20-75 mA and a diameter of 2-5 mm in the crossover under conditions in which the effective emittance of the beam, as a result of aberrations during its high-voltage shaping, increased by a factor of 3 or more (in kilovolts), and the calculated trajectories for 20 of 40 mm at the emitter are shown, where the markers D8 and D9 denote the positions of multiwire beam profile sensors.« less

Deep-UV Emitters and Detectors Based on Lattice-Matched Cubic Oxide Semiconductors (4.2 Optoelectronics)

DTIC Science & Technology

2015-05-14

calculated   by   dividing   photo-­‐‑ generated  current  by  the  optical  power  spectrum  of  the   lamp .    A   UV ...the optimized parameters for growth. Efforts led to significant increases in solar?blind detector responsivity (up to 0.1 A/W) with sub-­ nanoamp...Aug-2014 Approved for Public Release; Distribution Unlimited Final Report: Deep- UV Emitters and Detectors Based on Lattice- Matched Cubic Oxide

Optical properties of thermal control coating contaminated by MMH/N2O4 5-pound thruster in a vacuum environment with solar simulation

NASA Technical Reports Server (NTRS)

Sommers, R. D.; Raquet, C. A.; Cassidy, J. F.

1972-01-01

Cat-a-lac Black, and S13G thermal control coatings were exposed to the exhaust of a thruster in a simulated space environment. Vacuum was maintained at less than 10 to the minus 5th power torr during thruster firing in the liquid helium cooled facility. The thruster was fired in a 50-millisecond pulse mode and the accumulated firing time was 224 seconds. Solar absorptance (alpha sub s) and thermal emittance (sigma) of the coatings were measured in-situ at intervals of 300 pulses. A calorimetric technique was used to measure alpha sub s and sigma. The tests, technique, and test results are presented. The Cat-a-lac Black coatings showed no change in alpha sub s or sigma. The S13G showed up to 25 percent increase in alpha sub s but no change in sigma.

A survey on uncertainty in bioassay measurements carried out within the OMINEX project.

PubMed

Hurtgen, C; Cossonnet, C

2003-01-01

One of the topics covered by the OMINEX (Optimisation of Monitoring for Internal Exposure) project was to look at the bioassay measurements performed in the European laboratories. Questionnaires on bioassay measurements by alpha spectrometry or inductively coupled plasma-mass spectrometry (ICP-MS) were sent to European laboratories. The main objective was to collect information on analytical procedures and on the uncertainties associated with bioassay results. Alpha spectrometry is the technique most often used for the determination of alpha emitters, such as actinides in biological samples. ICP-MS is not used much as yet for routine measurements of actinides in biological samples, but is very sensitive for measurements of long-lived radionuclides. The different parameters influencing the uncertainties on the results and the minimum detectable amount have been investigated. Optimum conditions for achieving low result uncertainties and high sensitivity are given for alpha spectrometry and ICP-MS.

The measurement of alpha particle emissions from semiconductor memory materials

NASA Astrophysics Data System (ADS)

Bouldin, D. P.

1981-07-01

With the increasing concern for the affects of alpha particles on the reliability of semiconductor memories, an interest has arisen in characterizing semiconductor manufacturing materials for extremely low-level alpha-emitting contaminants. It is shown that four elements are of primary concern: uranium, thorium, radium, and polonium. Measurement of contamination levels are given relevance by first correlating them with alpha flux emission levels and then corre1ating these flux values with device soft error rates. Measurement techniques involve either measurements of elemental concentrations-applicable to only uranium and thorium - or direct measurements of alpha emission fluxes. Alpha fluxes are most usefully measured by means of ZnS scintillation counting, practical details of which are discussed. Materials measurements are reported for ceramics, solder, silicon, quartz, and various metals and organic materials. Ceramics and most metals have contamination levels of concern, but the high temperature processing normally used in semiconductor manufacturing and low total amounts reduce problems, at least for metals. Silicon, silicon compounds, and organic materials have been found to have no detectable alpha emitters. Finally, a brief discussion of the calibration of alpha sources for accelerated device testing is given, including practical details on the affects of source/chip separation and alignment variations.

Radiation resistant PIDECα cell using photon intermediate direct energy conversion and a 210Po source.

PubMed

Weaver, Charles L; Schott, Robert J; Prelas, Mark A; Wisniewski, Denis A; Rothenberger, Jason B; Lukosi, Eric D; Oh, Kyuhak

2018-02-01

Radiation damage is a significant concern with both alphavoltaic and betavoltaic cells because their performance degrades, especially with high-energy - (>200keV) beta and alpha particles. Indirect excitation methods, such as the Photon Intermediate Direct Energy Conversion (PIDEC) framework, can protect the transducer from radiation. A nuclear battery using a 90 Sr beta source was constructed by the author's research group, which demonstrated the radiation resistance of a PIDEC cell driven by beta particles (PIDECβ cell). Use of alpha sources to drive nuclear batteries would appear to be much more attractive than beta sources due to higher potential power density. However, they are also subject to higher rates of radiation damage. This paper describes the successful incorporation of alpha particles into the PIDEC framework using the alpha emitter 210 Po to form a PIDECα cell. The PIDECα cell transducer was exposed to alpha particles for over one year without experiencing adverse effects from radiation damage. Copyright © 2017 Elsevier Ltd. All rights reserved.

Rat epileptic seizures evoked by BmK {alpha}IV and its possible mechanisms involved in sodium channels

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

Chai Zhifang; Bai Zhantao; Zhang Xuying

2007-05-01

This study showed that rat unilateral intracerebroventricular injection of BmK {alpha}IV, a sodium channel modulator derived from scorpion Buthus martensi Karsch, induced clusters of spikes, epileptic discharges and convulsion-related behavioral changes. BmK {alpha}IV potently promoted the release of endogenous glutamate from rat cerebrocortical synaptosomes. In vitro examination of the effect of BmK {alpha}IV on intrasynaptosomal free calcium concentration [Ca{sup 2+}]{sub i} and sodium concentration [Na{sup +}]{sub i} revealed that BmK {alpha}IV-evoked glutamate release from synaptosomes was associated with an increase in Ca{sup 2+} and Na{sup +} influx. Moreover, BmK {alpha}IV-mediated glutamate release and ion influx was completely blocked by tetrodotoxin,more » a blocker of sodium channel. Together, these results suggest that the induction of BmK {alpha}IV-evoked epileptic seizures may be involved in the modulation of BmK {alpha}IV on tetrodotoxin-sensitive sodium channels located on the nerve terminal, which subsequently enhances the Ca{sup 2+} influx to cause an increase of glutamate release. These findings may provide some insight regarding the mechanism of neuronal action of BmK {alpha}IV in the central nervous system for understanding epileptogenesis involved in sodium channels.« less

A New Population of High-z, Dusty Lyman-alpha Emitters and Blobs Discovered by WISE: Feedback Caught in the Act?

NASA Technical Reports Server (NTRS)

Bridge, Carrie R.; Blain, Andrew; Borys, Colin J. K.; Petty, Sara; Benford, Dominic; Eisenhardt, Peter; Farrah, Duncan; Griffith, Roger, L.; Jarrett, Tom; Lonsdale, Carol;

Human monocytes and gingival fibroblasts release tumor necrosis factor-alpha, interleukin-1 alpha and interleukin-6 in response to particulate and soluble fractions of Prevotella melaninogenica and Fusobacterium nucleatum.

PubMed

Rossano, F; Rizzo, A; Sanges, M R; Cipollaro de L'Ero, G; Tufano, M A

1993-01-01

In this study we provide evidence that structural and soluble components of periodontopathogenic bacteria, such as Prevotella melaninogenica and Fusobacterium nucleatum, induce the release of cytokines in vitro known to cause in vivo necrotic inflammatory phenomena and bone resorption (tumor necrosis factor-alpha, interleukin-1 alpha and interleukin-6). Human monocytes and gingival fibroblasts were cultivated in vitro in the presence of both particulate and soluble bacterial fractions. A dose-dependent production of tumor necrosis factor-alpha by monocytes and gingival fibroblasts was observed in the presence of fractions of P. melaninogenica and F. nucleatum. Interleukin-1 alpha was produced in approximately the same quantities in the presence of soluble fractions of either P. melaninogenica or F. nucleatum, but in greater quantities in response to particulate fractions of P. melaninogenica. Monocytes released larger amounts of interleukin-1 alpha (about 3000 pg/ml) than gingival fibroblasts (about 1500 pg/ml). Interleukin-6 was released in greater quantities by monocytes in the presence of the pellet fraction of P. melaninogenica (about 5.5 ng/ml), but gingival fibroblasts released larger amounts of interleukin-6, especially in the presence of particulate and soluble components of F. nucleatum (about 12 ng/ml). The ability to induce the release of these cytokines notably increases the pathogenic potential of the bacteria involved in the damage of periodontal tissue.

Discharging Static Electricity From Inside A Glass Tube

NASA Technical Reports Server (NTRS)

Ellsbury, Walter L.

1994-01-01

Device that contains emitter of alpha particles discharges static electricity from inside wall of glass tube of volumetric-flow calibrator. Includes cylinder that has wall thickness of 1/16 in., diameter about 1/2 in. smaller than inside diameter of tube, and height that extends about 1/2 in. above piston that moves along tube and is part of calibrator.

Mixture quantification using PLS in plastic scintillation measurements.

PubMed

Bagán, H; Tarancón, A; Rauret, G; García, J F

2011-06-01

This article reports the capability of plastic scintillation (PS) combined with multivariate calibration (Partial least squares; PLS) to detect and quantify alpha and beta emitters in mixtures. While several attempts have been made with this purpose in mind using liquid scintillation (LS), no attempt was done using PS that has the great advantage of not producing mixed waste after the measurements are performed. Following this objective, ternary mixtures of alpha and beta emitters ((241)Am, (137)Cs and (90)Sr/(90)Y) have been quantified. Procedure optimisation has evaluated the use of the net spectra or the sample spectra, the inclusion of different spectra obtained at different values of the Pulse Shape Analysis parameter and the application of the PLS1 or PLS2 algorithms. The conclusions show that the use of PS+PLS2 applied to the sample spectra, without the use of any pulse shape discrimination, allows quantification of the activities with relative errors less than 10% in most of the cases. This procedure not only allows quantification of mixtures but also reduces measurement time (no blanks are required) and the application of this procedure does not require detectors that include the pulse shape analysis parameter. Copyright © 2011 Elsevier Ltd. All rights reserved.

Measurement of the Solar Absorptance and Thermal Emittance of Lunar Simulants

NASA Technical Reports Server (NTRS)

Gaier, James R.; Street, Kenneth W.; Gustafson, Robert J.

2010-01-01

The first comparative study of the reflectance spectra of lunar simulants is presented. All of the simulants except one had a wavelength-dependent reflectivity, rho(lambda), near 0.10 over the wavelength range of 8 to 25 microns, so they are highly emitting at room temperature and lower. The 300 K emittance, epsilon, of all the lunar simulants except one ranged from 0.884 to 0.906. The 300 K epsilon of JSC Mars-1 simulant was 0.927. There was considerably more variation in the lunar simulant reflectance in the solar spectral range (250 to 2500 nm) than in the thermal infrared. Larger particle size simulants reflected much less than those with smaller particle size. As expected, the lunar highlands simulants were more reflective in this wavelength range than the lunar mare simulants. The alpha of the simulants ranged from 0.413 to 0.817 for those with smaller particles and 0.669 to 0.906 for large particles. Although spectral differences were observed, the total integrated alpha for the simulants appears to be similar to that of lunar soils (0.65 to 0.88). These data are now available to be used in modeling the effects of dust on thermal control surfaces.

Radiobiological long-term accumulation of environmental alpha radioactivity in extracted human teeth and animal bones in Malaysia.

PubMed

Almayahi, B A; Tajuddin, A A; Jaafar, M S

2014-03-01

In this study, the radiobiological analysis of natural alpha emitters in extracted human teeth and animal bones from Malaysia was estimated. The microdistributions of alpha particles in tooth and bone samples were measured using CR-39 alpha-particle track detectors. The lowest and highest alpha emission rates in teeth in the Kedah and Perak states were 0.0080 ± 0.0005 mBq cm(-2) and 0.061 ± 0.008 mBq cm(-2), whereas those of bones in the Perlis and Kedah states were 0.0140 ± 0.0001 mBq cm(-2) and 0.7700 ± 0.0282 mBq cm(-2), respectively. The average alpha emission rate in male teeth was 0.0209 ± 0.0008 mBq cm(-2), whereas that of female teeth was 0.0199 ± 0.0010 mBq cm(-2). The alpha emission rate in teeth is higher in smokers (0.0228 ± 0.0008 mBq cm(-2)) than in non-smokers (0.0179 ± 0.0008 mBq cm(-2)). Such difference was found statistically significant (p < 0.01). Copyright © 2014 Elsevier Ltd. All rights reserved.

Design, construction and measurements of an alpha magnet as a solution for compact bunch compressor for the electron beam from Thermionic RF Gun

NASA Astrophysics Data System (ADS)

Rajabi, A.; Jazini, J.; Fathi, M.; Sharifian, M.; Shokri, B.

2018-03-01

The beam produced by a thermionic RF gun has wide energy spread that makes it unsuitable for direct usage in photon sources. Here in the present work, we optimize the extracted beam from a thermionic RF gun by a compact economical bunch compressor. A compact magnetic bunch compressor (Alpha magnet) is designed and constructed. A comparison between simulation results and experimental measurements shows acceptable conformity. The beam dynamics simulation results show a reduction of the energy spread as well as a compression of length less than 1 ps with 2.3 mm-mrad emittance.

Systems and methods for neutron detection using scintillator nano-materials

DOEpatents

Letant, Sonia Edith; Wang, Tzu-Fang

2016-03-08

In one embodiment, a neutron detector includes a three dimensional matrix, having nanocomposite materials and a substantially transparent film material for suspending the nanocomposite materials, a detector coupled to the three dimensional matrix adapted for detecting a change in the nanocomposite materials, and an analyzer coupled to the detector adapted for analyzing the change detected by the detector. In another embodiment, a method for detecting neutrons includes receiving radiation from a source, converting neutrons in the radiation into alpha particles using converter material, converting the alpha particles into photons using quantum dot emitters, detecting the photons, and analyzing the photons to determine neutrons in the radiation.

Production of interleukin-1alpha by human endometrial stromal cells is triggered during menses and dysfunctional bleeding and is induced in culture by epithelial interleukin-1alpha released upon ovarian steroids withdrawal.

PubMed

Pretto, Chrystel M; Gaide Chevronnay, Héloïse P; Cornet, Patricia B; Galant, Christine; Delvaux, Denis; Courtoy, Pierre J; Marbaix, Etienne; Henriet, Patrick

2008-10-01

Endometrial breakdown during menstruation and dysfunctional bleeding is triggered by the abrupt expression of matrix metalloproteinases (MMPs), including interstitial collagenase (MMP-1). The paracrine induction of MMP-1 in stromal cells via epithelium-derived IL-1alpha is repressed by ovarian steroids. However, the control by estradiol (E) and progesterone (P) of endometrial IL-1alpha expression and bioactivity remains unknown. Variations of endometrial IL-1alpha mRNA and protein along the menstrual cycle and during dysfunctional bleeding were determined using RT-PCR, in situ hybridization, and immunolabeling. The mechanism of EP control was analyzed using culture of explants, laser capture microdissection, and purified cells. Data were compared with expression changes of IL-1beta and IL-1 receptor antagonist. IL-1alpha is synthesized by epithelial cells throughout the cycle but E and/or P prevents its release. In contrast, endometrial stromal cells produce IL-1alpha only at menses and during irregular bleeding in areas of tissue breakdown. Stromal expression of IL-1alpha, like that of MMP-1, is repressed by P (alone or with E) but triggered by epithelium-derived IL-1alpha released upon EP withdrawal. Our experiments in cultured endometrium suggest that IL-1alpha released by epithelial cells triggers the production of IL-1alpha by stromal cells in a paracrine amplification loop to induce MMP-1 expression during menstruation and dysfunctional bleeding. All three steps of this amplification cascade are repressed by EP.

Expected Backgrounds of the BetaCage, an Ultra-sensitive Screener for Surface Contamination

NASA Astrophysics Data System (ADS)

Wang, Boqian; Bunker, Raymond; Schnee, Richard; Bowles, Michael; Kos, Marek; Ahmed, Zeeshan; Golwala, Sunil; Nelson, Robert; Grant, Darren

2013-04-01

Material screening for low-energy betas and alphas is necessary for rare-event-search experiments, such as dark matter and neutrinoless double-beta decay searches where surface radiocontamination has become a significant background. The BetaCage, a gaseous neon time-projection chamber, has been proposed as a screener for emitters of low-energy betas and alphas to which existing screening facilities are insufficiently sensitive. The expected sensitivity is 0.1 betas / (keV m^2 day) and 0.1 alphas / (m^2 day). Expected backgrounds are dominated by Compton scattering of external photons in the sample to be screened; radioassays and simulations indicate backgrounds from detector materials and radon daughters should be subdominant. We will report on details of the background simulations and the detector design that allows discrimination to reach these sensitivity levels.

Detection of 210Po on filter papers 16 years after use for the collection of short-lived radon progeny in a room.

PubMed

Abu-Jarad, F; Fazal-ur-Rehman

2003-01-01

Radon gas was allowed to accumulate in its radium source and then injected into a 36 m(3) test room, resulting in an initial radon concentration of 15 kBq m(-3). Filter papers were used to collect the short-lived radon progeny and thus to measure the Potential Alpha Energy Concentration (PAEC) in-situ in the year 1984 at different times and conditions according to the experimental design. The radon progeny collected on the filter papers were studied as a function of aerosol particle concentration ranging from 10(2)-10(5) particles cm(-3) in three different experiments. The highest aerosol particle concentration was generated by indoor cigarette smoking. Those filters were stored after the experiment, and were used after 16 years to study the activity of the radon long-lived alpha emitter progeny, (210)Po (T(1/2)=138 days). This isotope is separated from the short-lived progeny by (210)Pb beta emitter with 22.3 years half-life. After 16 years' storage of these filters, each filter paper was sandwiched and wrapped between two CR-39 nuclear track detectors, to put the detectors in contact with the surfaces of different filters, for 337 days. Correlation between the PAEC measured using filter papers in the year 1984 and the activity of long-lived alpha emitter (210)Po on the same filter papers measured in the year 2000 were studied. The results of the (210)Po activity showed a very good correlation of 0.92 with the PAEC 16 years ago. The results also depict that the PAEC and (210)Po activity in indoor air increased with the increase of aerosol particle concentration, which shows the attachment of short-lived radon progeny with the aerosol particles. The experiment proves that indoor cigarette smoking is a major source of aerosol particles carrying radon progeny and, thus, indoor cigarette smoking is an additional source of internal radiation hazard to the occupants whether smoker or non-smoker.

Testing the stand-alone microbeam at Columbia University.

PubMed

Garty, G; Ross, G J; Bigelow, A W; Randers-Pehrson, G; Brenner, D J

2006-01-01

The stand-alone microbeam at Columbia University presents a novel approach to biological microbeam irradiation studies. Foregoing a conventional accelerator as a source of energetic ions, a small, high-specific-activity, alpha emitter is used. Alpha particles emitted from this source are focused using a compound magnetic lens consisting of 24 permanent magnets arranged in two quadrupole triplets. Using a 'home made' 6.5 mCi polonium source, a 1 alpha particle s(-1), 10 microm diameter microbeam can, in principle, be realised. As the alpha source energy is constant, once the microbeam has been set up, no further adjustments are necessary apart from a periodic replacement of the source. The use of permanent magnets eliminates the need for bulky power supplies and cooling systems required by other types of ion lenses and greatly simplifies operation. It also makes the microbeam simple and cheap enough to be realised in any large lab. The Microbeam design as well as first tests of its performance, using an accelerator-based beam are presented here.

Alpha 2 LASSO Data Bundles

DOE Data Explorer

Gustafson, William Jr; Vogelmann, Andrew; Endo, Satoshi; Toto, Tami; Xiao, Heng; Li, Zhijin; Cheng, Xiaoping; Kim, Jinwon; Krishna, Bhargavi

2015-08-31

The Alpha 2 release is the second release from the LASSO Pilot Phase that builds upon the Alpha 1 release. Alpha 2 contains additional diagnostics in the data bundles and focuses on cases from spring-summer 2016. A data bundle is a unified package consisting of LASSO LES input and output, observations, evaluation diagnostics, and model skill scores. LES input include model configuration information and forcing data. LES output includes profile statistics and full domain fields of cloud and environmental variables. Model evaluation data consists of LES output and ARM observations co-registered on the same grid and sampling frequency. Model performance is quantified by skill scores and diagnostics in terms of cloud and environmental variables.

GTP analogues promote release of the alpha subunit of the guanine nucleotide binding protein, Gi2, from membranes of rat glioma C6 BU1 cells.

PubMed Central

Milligan, G; Mullaney, I; Unson, C G; Marshall, L; Spiegel, A M; McArdle, H

1988-01-01

The major pertussis-toxin-sensitive guanine nucleotide-binding protein of rat glioma C6 BU1 cells corresponded immunologically to Gi2. Antibodies which recognize the alpha subunit of this protein indicated that it has an apparent molecular mass of 40 kDa and a pI of 5.7. Incubation of membranes of these cells with guanosine 5'-[beta gamma-imido]triphosphate, or other analogues of GTP, caused release of this polypeptide from the membrane in a time-dependent manner. Analogues of GDP or of ATP did not mimic this effect. The GTP analogues similarly caused release of the alpha subunit of Gi2 from membranes of C6 cells in which this G-protein had been inactivated by pretreatment with pertussis toxin. The beta subunit was not released from the membrane under any of these conditions, indicating that the release process was a specific response to the dissociation of the G-protein after binding of the GTP analogue. Similar nucleotide profiles for release of the alpha subunits of forms of Gi were noted for membranes of both the neuroblastoma x glioma hybrid cell line NG108-15 and of human platelets. These data provide evidence that: (1) pertussis-toxin-sensitive G-proteins, in native membranes, do indeed dissociate into alpha and beta gamma subunits upon activation; (2) the alpha subunit of 'Gi-like' proteins need not always remain in intimate association with the plasma membrane; and (3) the alpha subunit of Gi2 can still dissociate from the beta/gamma subunits after pertussis-toxin-catalysed ADP-ribosylation. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 5. Fig. 6. Fig. 7. Fig. 8. PMID:3140801

Radiation-induced biologic bystander effect elicited in vitro by targeted radiopharmaceuticals labeled with alpha-, beta-, and auger electron-emitting radionuclides.

PubMed

Boyd, Marie; Ross, Susan C; Dorrens, Jennifer; Fullerton, Natasha E; Tan, Ker Wei; Zalutsky, Michael R; Mairs, Robert J

2006-06-01

Recent studies have shown that indirect effects of ionizing radiation may contribute significantly to the effectiveness of radiotherapy by sterilizing malignant cells that are not directly hit by the radiation. However, there have been few investigations of the importance of indirect effects in targeted radionuclide treatment. Our purpose was to compare the induction of bystander effects by external beam gamma-radiation with those resultant from exposure to 3 radiohaloanalogs of metaiodobenzylguanidine (MIBG): (131)I-MIBG (low-linear-energy-transfer [LET] beta-emitter), (123)I-MIBG (potentially high-LET Auger electron emitter), and meta-(211)At-astatobenzylguanidine ((211)At-MABG) (high-LET alpha-emitter). Two human tumor cell lines-UVW (glioma) and EJ138 (transitional cell carcinoma of bladder)-were transfected with the noradrenaline transporter (NAT) gene to enable active uptake of MIBG. Medium from cells that accumulated the radiopharmaceuticals or were treated with external beam radiation was transferred to cells that had not been exposed to radioactivity, and clonogenic survival was determined in donor and recipient cultures. Over the dose range 0-9 Gy of external beam radiation of donor cells, 2 Gy caused 30%-40% clonogenic cell kill in recipient cultures. This potency was maintained but not increased by higher dosage. In contrast, no corresponding saturation of bystander cell kill was observed after treatment with a range of activity concentrations of (131)I-MIBG, which resulted in up to 97% death of donor cells. Cellular uptake of (123)I-MIBG and (211)At-MABG induced increasing recipient cell kill up to levels that resulted in direct kill of 35%-70% of clonogens. Thereafter, the administration of higher activity concentrations of these high-LET emitters was inversely related to the kill of recipient cells. Over the range of activity concentrations examined, neither direct nor indirect kill was observed in cultures of cells not expressing the NAT and, thus, incapable of active uptake of MIBG. Potent toxins are generated specifically by cells that concentrate radiohalogenated MIBG. These may be LET dependent and distinct from those elicited by conventional radiotherapy.

Fuel elements of thermionic converters

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

Hunter, R.L.; Gontar, A.S.; Nelidov, M.V.

1997-01-01

Work on thermionic nuclear power systems has been performed in Russia within the framework of the TOPAZ reactor program since the early 1960s. In the TOPAZ in-core thermionic convertor reactor design, the fuel element`s cladding is also the thermionic convertor`s emitter. Deformation of the emitter can lead to short-circuiting and is the primary cause of premature TRC failure. Such deformation can be the result of fuel swelling, thermocycling, or increased unilateral pressure on the emitter due to the release of gaseous fission products. Much of the work on TRCs has concentrated on preventing or mitigating emitter deformation by improving themore » following materials and structures: nuclear fuel; emitter materials; electrical insulators; moderator and reflector materials; and gas-exhaust device. In addition, considerable effort has been directed toward the development of experimental techniques that accurately mimic operational conditions and toward the creation of analytical and numerical models that allow operational conditions and behavior to be predicted without the expense and time demands of in-pile tests. New and modified materials and structures for the cores of thermionic NPSs and new fabrication processes for the materials have ensured the possibility of creating thermionic NPSs for a wide range of powers, from tens to several hundreds of kilowatts, with life spans of 5 to 10 years.« less

Sample preparation for the determination of 241Am in sediments utilizing gamma-spectroscopy.

PubMed

Ristic, M; Degetto, S; Ast, T; Cantallupi, C

2002-01-01

This paper describes a procedure developed to separate americium-241 from the bulk of a sample by coprecipitation followed by high sensitivity gamma-counting of the concentrate in a well-type detector. It enables the measurement of 241Am at low concentrations, e.g. fallout levels in soils and sediments, or where large sample sizes are not available. The method is much faster and more reliable than those involving separation from other alpha-emitters, electroplating and alpha-spectrometry. A number of tracer experiments was performed in order to optimize the conditions for coprecipitation of 241Am from sediment leachates. The general outline of the determination of americium is also given.

Mechanisms of stimulation of interleukin-1 beta and tumor necrosis factor-alpha by Mycobacterium tuberculosis components.

PubMed Central

Zhang, Y; Doerfler, M; Lee, T C; Guillemin, B; Rom, W N

1993-01-01

The granulomatous immune response in tuberculosis is characterized by delayed hypersensitivity and is mediated by various cytokines released by the stimulated mononuclear phagocytes, including tumor necrosis factor-alpha (TNF alpha) and IL-1 beta. We have demonstrated that Mycobacterium tuberculosis cell wall component lipoarabinomannan (LAM), mycobacterial heat shock protein-65 kD, and M. tuberculosis culture filtrate, devoid of LPS as assessed by the Amebocyte Lysate assay, stimulate the production of TNF alpha and IL-1 beta proteins and mRNA from mononuclear phagocytes (THP-1 cells). The effect of LAM on the release of these cytokines was specific, as only LAM stimulation was inhibited by anti-LAM monoclonal antibody. Interestingly, we found that LAM and Gram-negative bacterial cell wall-associated endotoxin LPS may share a similar mechanism in their stimulatory action as demonstrated by inhibition of TNF alpha and IL-1 beta release by monoclonal antibodies to CD14. Anti-CD14 monoclonal antibody MY4 inhibited both TNF alpha and IL-1 beta release with LAM and LPS but no effect was observed with other mycobacterial proteins. An isotype antibody control did not inhibit release of cytokines under the same experimental conditions. M. tuberculosis and its components upregulated IL-1 beta and TNF alpha mRNAs in THP-1 cells. Nuclear run-on assay for IL-1 beta demonstrated that LAM increased the transcription rate. The induction of IL-1 beta was regulated at the transcriptional level, in which these stimuli acted through cis-acting element(s) on the 5' flanking region of the IL-1 beta genomic DNA. M. tuberculosis cell wall component LAM acts similarly to LPS in activating mononuclear phagocyte cytokine TNF alpha and IL-1 beta release through CD14 and synthesis at the transcriptional level; both cytokines are key participants in the host immune response to tuberculosis. Images PMID:7683696

IgE reactivity to alpha1 and alpha2 chains of bovine type 1 collagen in children with bovine gelatin allergy.

PubMed

Sakaguchi, M; Hori, H; Hattori, S; Irie, S; Imai, A; Yanagida, M; Miyazawa, H; Toda, M; Inouye, S

1999-09-01

Anaphylactic reactions to measles, mumps, and rubella vaccines, including gelatin as a stabilizer, have been reported. It had been found that most of these reactions to live vaccines are caused by the bovine gelatin included in these vaccines. Gelatin mainly includes denatured type I collagen, which consists of alpha1 and alpha2 chains. The current study was designed to investigate the IgE reactivity to alpha1 and alpha2 chains of bovine type I collagen in gelatin-sensitive children. Serum samples were taken from 10 children who had anaphylaxis to the vaccines and high levels of specific IgE to bovine gelatin. Bovine type I collagen was isolated from bovine skin and then separated to alpha1 and alpha2 chains by column chromatography. IgE reactivity to denatured type I collagen and its alpha1 and alpha2 chains was analyzed by immunoblotting, ELISA, and histamine release from the mast cells passive sensitized with IgE antibodies in pooled serum of the children. All children had specific IgE to bovine type I collagen. Furthermore, IgE antibodies in their sera reacted with the alpha;2 chain but not with the alpha1 chain. Similarly, the mast cells sensitized with pooled sera in the children showed alpha2 chain-specific histamine release but not alpha1 chain-specific histamine release. In gelatin allergy denatured bovine type I collagen is a major allergen and IgE-binding sites exist in the alpha2 chain of type I collagen.

Effects of prostaglandin F(2alpha)and carbachol on MAP kinases, cytosolic phospholipase A(2)and arachidonic acid release in cat iris sphincter smooth muscle cells.

PubMed

Husain, S; Abdel-Latif, A A

2001-05-01

The signal transduction pathways initiated by Ca(2+)-mobilizing agonists, such as prostaglandin F(2alpha)(PGF(2alpha)) and carbachol (CCh), leading to activation of cytosolic phospholipase A(2)(cPLA(2)) and arachidonic acid (AA) release in a wide variety of tissues remain obscure. To further define the role of protein kinases in receptor mediated stimulation of cPLA(2)and consequently AA release we have investigated the role of mitogen-activated protein (MAP) kinases and protein kinase C (PKC) in PGF(2alpha)- and CCh-induced cPLA(2)phosphorylation and AA release in cat iris sphincter smooth muscle (CISM) cells. The cells were prelabeled with [(3)H]AA for 24 hr and incubated in the absence or presence of the agonist for 5-10 min as indicated. MAP kinases activities and cPLA(2)phosphorylation were determined in immunoprecipitates obtained by using anti-p38 MAP kinase and anti-cPLA(2)antibodies. We found that: (a) PGF(2alpha)and CCh increased p38 MAP kinase activity by 197 and 215%, respectively, and increased p42/p44 MAP kinase activity by 200 and 125%, respectively. (b) SB202190, a p38 MAP kinase specific inhibitor, inhibited PGF(2alpha)- and CCh-induced cPLA(2)phosphorylation by 92 and 85%, respectively, and AA release by 62 and 78%, respectively. (c) PD98059, a p42/p44 MAP kinase inhibitor, inhibited CCh-induced cPLA(2)phosphorylation by 70% and AA release by 71%, but had no effect on that of PGF(2alpha). (d) Inhibition of PKC activity by RO 31-8220 inhibited both PGF(2alpha)- and CCh-stimulation of p38 MAP kinase, p42/p44 MAP kinases and cPLA(2)phosphorylation. We conclude from these results that in CISM cells PGF(2alpha)-induced cPLA(2)phosphorylation and AA release is mediated through p38 MAP kinase, but not through p42/p44 MAP kinases, whereas that of CCh is mediated through both p38 MAP kinase and p42/p44 MAP kinases. These effects of PGF(2alpha)and CCh are regulated by the MAP kinases in a PKC-dependent manner. Studies aimed at elucidating the role of protein kinases in the coupling mechanism between the activation of PGF(2alpha)and muscarinic receptors, and the stimulation of cPLA(2)and AA release in the smooth muscles of the iris-ciliary body will provide important information about the role of protein kinases signaling pathways in smooth muscle function, as well as about the mechanism of the intraocular pressure-lowering effects of PGF(2alpha)and its analog, latanoprost, in glaucoma therapy. Copyright 2001 Academic Press.

Survey parameters for detecting 21cm - Lyα emitter cross correlations with the Square Kilometre Array

NASA Astrophysics Data System (ADS)

Hutter, Anne; Trott, Cathryn M.; Dayal, Pratika

2018-06-01

Detections of the cross correlation signal between the 21cm signal during reionization and high-redshift Lyman Alpha emitters (LAEs) are subject to observational uncertainties which mainly include systematics associated with radio interferometers and LAE selection. These uncertainties can be reduced by increasing the survey volume and/or the survey luminosity limit, i.e. the faintest detectable Lyman Alpha (Lyα) luminosity. We use our model of high-redshift LAEs and the underlying reionization state to compute the uncertainties of the 21cm-LAE cross correlation function at z ≃ 6.6 for observations with SKA1-Low and LAE surveys with Δz = 0.1 for three different values of the average IGM ionization state (⟨χHI⟩≃ 0.1, 0.25, 0.5). At z ≃ 6.6, we find SILVERRUSH type surveys, with a field of view of 21 deg2 and survey luminosity limits of Lα ≥ 7.9 × 1042erg s-1, to be optimal to distinguish between an inter-galactic medium (IGM) that is 50%, 25% and 10% neutral, while surveys with smaller fields of view and lower survey luminosity limits, such as the 5 and 10 deg2 surveys with WFIRST, can only discriminate between a 50% and 10% neutral IGM.

Structural Evidence for a Sequential Release Mechanism for Activation of Heterotrimeric G Proteins

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

Kapoor, Neeraj; Menon, Santosh T.; Chauhan, Radha

2010-01-12

Heptahelical G-protein (heterotrimeric guanine nucleotide-binding protein)-coupled receptors couple to heterotrimeric G proteins to relay extracellular signals to intracellular signaling networks, but the molecular mechanism underlying guanosine 5'-diphosphate (GDP) release by the G protein {alpha}-subunit is not well understood. Amino acid substitutions in the conserved {alpha}5 helix of Gi, which extends from the C-terminal region to the nucleotide-binding pocket, cause dramatic increases in basal (receptor-independent) GDP release rates. For example, mutant G{alpha}{sub i1}-T329A shows an 18-fold increase in basal GDP release rate and, when expressed in culture, it causes a significant decrease in forskolin-stimulated cAMP accumulation. The crystal structure of G{alpha}{submore » i1}-T329A {center_dot} GDP shows substantial conformational rearrangement of the switch I region and additional striking alterations of side chains lining the catalytic pocket that disrupt the Mg{sup +2} coordination sphere and dislodge bound Mg{sup +2}. We propose a 'sequential release' mechanism whereby a transient conformational change in the {alpha}5 helix alters switch I to induce GDP release. Interestingly, this mechanistic model for heterotrimeric G protein activation is similar to that suggested for the activation of the plant small G protein Rop4 by RopGEF8.« less

The effects of alpha tocopherol supplementation on monocyte function. Decreased lipid oxidation, interleukin 1 beta secretion, and monocyte adhesion to endothelium.

PubMed Central

Devaraj, S; Li, D; Jialal, I

1996-01-01

Low levels of alpha tocopherol are related to a higher incidence of cardiovascular disease and increased intake appears to afford protection against cardiovascular disease. In addition to decreasing LDL oxidation, alpha tocopherol may exert intracellular effects on cells crucial in atherogenesis, such as monocytes. Hence, the aim of this study was to test the effect of alpha tocopherol supplementation on monocyte function relevant to atherogenesis. Monocyte function was assessed in 21 healthy subjects at baseline, after 8 wk of supplementation with d-alpha tocopherol (1,200 IU/d) and after a 6-wk washout phase. The release of reactive oxygen species (superoxide anion, hydrogen peroxide), lipid oxidation, release of the potentially atherogenic cytokine, interleukin 1 beta, and monocyte-endothelial adhesion were studied in the resting state and after activation of the monocytes with lipopolysaccharide at 0, 8, and 14 wk. There was a 2.5-fold increase in plasma lipid-standardized and monocyte alpha tocopherol levels in the supplemented phase. After alpha tocopherol supplementation, there were significant decreases in release of reactive oxygen species, lipid oxidation, IL-1 beta secretion, and monocyte-endothelial cell adhesion, both in resting and activated cells compared with baseline and washout phases. Studies with the protein kinase C inhibitor, Calphostin C, suggest that the inhibition of reactive oxygen species release and lipid oxidation is due to an inhibition of protein kinase C activity by alpha tocopherol. Thus, this study provides novel evidence for an intracellular effect of alpha tocopherol in monocytes that is antiatherogenic. PMID:8698868

Characterization and identification of a chymotryptic hydrolysate of alpha-lactalbumin stimulating cholecystokinin release in STC-1 cells.

PubMed

Catiau, Lucie; Delval-Dubois, Véronique; Guillochon, Didier; Nedjar-Arroume, Naïma

2011-11-01

Alpha-lactalbumin hydrolysate is of significant interest, due to its potential application as a source of bioactive peptides in nutraceutical and pharmaceutical domains. This study was focused on the cholecystokinin (CCK) family compounds which are small peptides involved in the satiety control. The action of chymotryptic hydrolysate of alpha-lactalbumin on cholecystokinin release from intestinal endocrine STC-1 cells was investigated. We demonstrated for the first time that a chymotryptic hydrolysate of alpha-lactalbumin was able to highly stimulate CCK-releasing activity from STC-1 cells. The peptidic hydrolysate was characterized by LC/MS and MS/MS, thus highlighting the presence of 11 fractions containing 21 peptides, each potentially having the desired activity.

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

Scott, B.R.; Muggenburg, B.A.; Welsh, C.A.

The alpha emitter plutonium-238 ({sup 238}Pu), which is produced in uranium-fueled, light-water reactors, is used as a thermoelectric power source for space applications. Inhalation of a mixed oxide form of Pu is the most likely mode of exposure of workers and the general public. Occupational exposures to {sup 238}PuO{sub 2} have occurred in association with the fabrication of radioisotope thermoelectric generators. Organs and tissue at risk for deterministic and stochastic effects of {sup 238}Pu-alpha irradiation include the lung, liver, skeleton, and lymphatic tissue. Little has been reported about the effects of inhaled {sup 238}PuO{sub 2} on peripheral blood cell countsmore » in humans. The purpose of this study was to investigate hematological responses after a single inhalation exposure of Beagle dogs to alpha-emitting {sup 238}PuO{sub 2} particles and to extrapolate results to humans.« less

Tailoring Thin Film-Lacquer Coatings for Space Application

NASA Technical Reports Server (NTRS)

Peters, Wanda C.; Harris, George; Miller, Grace; Petro, John

1998-01-01

Thin film coatings have the capability of obtaining a wide range of thermal radiative properties, but the development of thin film coatings can sometimes be difficult and costly when trying to achieve highly specular surfaces. Given any space mission's thermal control requirements, there is often a need for a variation of solar absorptance (Alpha(s)), emittance (epsilon) and/or highly specular surfaces. The utilization of thin film coatings is one process of choice for meeting challenging thermal control requirements because of its ability to provide a wide variety of Alpha(s)/epsilon ratios. Thin film coatings' radiative properties can be tailored to meet specific thermal control requirements through the use of different metals and the variation of dielectric layer thickness. Surface coatings can be spectrally selective to enhance radiative coupling and decoupling. The application of lacquer to a surface can also provide suitable specularity for thin film application without the cost and difficulty associated with polishing.

In vitro evaluation of the immunotoxic potential of perfluorinated compounds (PFCs)

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

Corsini, Emanuela, E-mail: emanuela.corsini@unimi.it; Avogadro, Anna; Galbiati, Valentina

2011-01-15

There is evidence from both epidemiology and laboratory studies that perfluorinated compounds may be immunotoxic, affecting both cell-mediated and humoral immunity. The overall goal of this study was to investigate the mechanisms underlying the immunotoxic effects of perfluorooctane sulfonate (PFOS) and perfluorooctane acid (PFOA), using in vitro assays. The release of the pro-inflammatory cytokines IL-6, IL-8, and TNF-{alpha} was evaluated in lipolysaccharide (LPS)-stimulated human peripheral blood leukocytes and in the human promyelocytic cell line THP-1, while the release of IL-4, IL-10 and IFN-{gamma} was evaluated in phytohaemagglutinin (PHA)-stimulated peripheral blood leukocytes. PFOA and PFOS suppressed LPS-induced TNF-{alpha} production in primarymore » human cultures and THP-1 cells, while IL-8 was suppressed only in THP-1 cells. IL-6 release was decreased only by PFOS. Both PFOA and PFOS decreased T-cell derived, PHA-induced IL-4 and IL-10 release, while IFN-{gamma} release was affected only by PFOS. In all instances, PFOS was more potent than PFOA. Mechanistic investigations carried out in THP-1 cells demonstrated that the effect on cytokine release was pre-transcriptional, as assessed by a reduction in LPS-induced TNF-{alpha} mRNA expression. Using siRNA, a role for PPAR-{alpha} could be demonstrated for PFOA-induced immunotoxicity, while an inhibitory effect on LPS-induced I-{kappa}B degradation could explain the immunomodulatory effect of PFOS. The dissimilar role of PPAR-{alpha} in PFOA and PFOS-induced immunotoxicity was consistent with the differing effects observed on LPS-induced MMP-9 release: PFOA, as the PPAR-{alpha} agonist fenofibrate, modulated the release, while PFOS had no effect. Overall, these studies suggest that PFCs directly suppress cytokine secretion by immune cells, and that PFOA and PFOS have different mechanisms of action.« less

Monte Carlo calculations of the cellular S-values for α-particle-emitting radionuclides incorporated into the nuclei of cancer cells of the MDA-MB231, MCF7 and PC3 lines.

PubMed

Rojas-Calderón, E L; Ávila, O; Ferro-Flores, G

2018-05-01

S-values (dose per unit of cumulated activity) for alpha particle-emitting radionuclides and monoenergetic alpha sources placed in the nuclei of three cancer cell models (MCF7, MDA-MB231 breast cancer cells and PC3 prostate cancer cells) were obtained by Monte Carlo simulation. The MCNPX code was used to calculate the fraction of energy deposited in the subcellular compartments due to the alpha sources in order to obtain the S-values. A comparison with internationally accepted S-values reported by the MIRD Cellular Committee for alpha sources in three sizes of spherical cells was also performed leading to an agreement within 4% when an alpha extended source uniformly distributed in the nucleus is simulated. This result allowed to apply the Monte Carlo Methodology to evaluate S-values for alpha particles in cancer cells. The calculation of S-values for nucleus, cytoplasm and membrane of cancer cells considering their particular geometry, distribution of the radionuclide source and chemical composition by means of Monte Carlo simulation provides a good approach for dosimetry assessment of alpha emitters inside cancer cells. Results from this work provide information and tools that may help researchers in the selection of appropriate radiopharmaceuticals in alpha-targeted cancer therapy and improve its dosimetry evaluation. Copyright © 2018 Elsevier Ltd. All rights reserved.

Aging increases amyloid beta-peptide-induced 8-iso-prostaglandin F2alpha release from rat brain.

PubMed

Brunetti, Luigi; Michelotto, Barbara; Orlando, Giustino; Recinella, Lucia; Di Nisio, Chiara; Ciabattoni, Giovanni; Vacca, Michele

2004-01-01

In order to investigate whether amyloid beta-peptide-induced oxidative damage in the brain could be related to aging, we studied the release of 8-iso-prostaglandin (PG)F2alpha, a stable marker of cellular oxidative stress, in brain synaptosomes from Wistar rats of different ages (3, 6, 12, 18 months old), both basally and after amyloid beta-peptide (1-40) perfusion. We found that basal release of 8-iso-PGF2alpha was not significantly different among all age groups of rats. Either phospholipase A2 activation induced by calcium ionophore A23187 (10 nM) or amyloid beta-peptide (5 microM) did not modify isoprostane release, when these substances were used alone. In contrast, amyloid beta-peptide (1-5 microM) preincubation caused a dose-dependent increase of A23187-stimulated 8-iso-PGF2alpha release in each age group, which was also strikingly correlated to aging of rats. Furthermore, ferric ammonium sulfate stimulates isoprostane production to levels comparable to those induced by amyloid beta-peptide. In conclusion, although 8-iso-PGF2alpha production from rat brain synaptosomes is independent from aging in the basal state, aging renders neurons more vulnerable to amyloid beta-peptide-induced oxidative toxicity.

Confirmation of a Steep Luminosity Function for Ly alpha Emitters at z 5.7: a Major Component of Reionization

NASA Technical Reports Server (NTRS)

Dressler, Alan; Henry, Alaina L.; Martin, Crystal L.; Sawicki, Marcin; McCarthy, Patrick; Villaneuva, Edward

2014-01-01

We report the first direct and robust measurement of the faint-end slope of the Ly-alpha emitter (LAE) luminosity function at z = 5.7. Candidate LAEs from a low-spectral-resolution blind search with IMACS on Magellan- Baade were targeted at higher resolution to distinguish high redshift LAEs from foreground galaxies. All but 2 of our 42 single-emission-line systems are fainter than F = 2.0×10(exp-17) ergs s(exp-1) cm(exp-2), making these the faintest emission-lines observed for a z = 5.7 sample with known completeness, an essential property for determining the faint end slope of the LAE luminosity function. We find 13 LAEs as compared to 29 foreground galaxies, in very good agreement with the modeled foreground counts predicted in Dressler et al. (2011a) that had been used to estimate a faint-end slope of alpha = -2.0 for the LAE luminosity function. A 32% LAE fraction, LAE/(LAE+foreground) within the flux interval F = 2-20 × 10(exp-18) ergs s(exp-1) cm(exp-2) constrains the faint end slope of the luminosity function to -1.95 greater than alpha greater than -2.35 (1 delta). We show how this steep LF should provide, to the limit of our observations, more than 20% of the flux necessary to maintain ionization at z = 5.7, with a factor-of-ten extrapolation in flux reaching more than 55%. We suggest that this bodes well for a comparable contribution by similar, low-mass star forming galaxies at higher-redshift - within the reionization epoch at z greater than approximately 7, only 250 Myr earlier - and that such systems provide a substantial, if not dominant, contribution to the late-stage reionization of the IGM.

Biokinetics of nuclear fuel compounds and biological effects of nonuniform radiation.

PubMed Central

Lang, S; Servomaa, K; Kosma, V M; Rytömaa, T

1995-01-01

Environmental releases of insoluble nuclear fuel compounds may occur at nuclear power plants during normal operation, after nuclear power plant accidents, and as a consequence of nuclear weapons testing. For example, the Chernobyl fallout contained extensive amounts of pulverized nuclear fuel composed of uranium and its nonvolatile fission products. The effects of these highly radioactive particles, also called hot particles, on humans are not well known due to lack of reliable data on the extent of the exposure. However, the biokinetics and biological effects of nuclear fuel compounds have been investigated in a number of experimental studies using various cellular systems and laboratory animals. In this article, we review the biokinetic properties and effects of insoluble nuclear fuel compounds, with special reference to UO2, PuO2, and nonvolatile, long-lived beta-emitters Zr, Nb, Ru, and Ce. First, the data on hot particles, including sources, dosimetry, and human exposure are discussed. Second, the biokinetics of insoluble nuclear fuel compounds in the gastrointestinal tract and respiratory tract are reviewed. Finally, short- and long-term biological effects of nonuniform alpha- and beta-irradiation on the gastrointestinal tract, lungs, and skin are discussed. Images p920-a Figure 1. PMID:8529589

Enhanced adhesion by high energy bombardment

NASA Technical Reports Server (NTRS)

Griffith, Joseph E. (Inventor); Qiu, Yuanxun (Inventor); Tombrello, Thomas A. (Inventor)

1984-01-01

Films (12) of gold, copper, silicon nitride, or other materials are firmly bonded to insulator substrates (12) such as silica, a ferrite, or Teflon (polytetrafluorethylene) by irradiating the interface with high energy ions. Apparently, track forming processes in the electronic stopping region cause intermixing in a thin surface layer resulting in improved adhesion without excessive doping. Thick layers can be bonded by depositing or doping the interfacial surfaces with fissionable elements or alpha emitters.

Effect of pro-inflammatory mediators on membrane-associated mucins expressed by human ocular surface epithelial cells.

PubMed

Albertsmeyer, Ann-Christin; Kakkassery, Vinodh; Spurr-Michaud, Sandra; Beeks, Olivia; Gipson, Ilene K

2010-03-01

Membrane-associated mucins are altered on the ocular surface in non-Sjögren's dry eye. This study sought to determine if inflammatory mediators, present in tears of dry eye patients, regulate membrane-associated mucins MUC1 and -16 at the level of gene expression, protein biosynthesis and/or ectodomain release. A human corneal limbal epithelial cell line (HCLE), which produces membrane-associated mucins, was used. Cells were treated with interleukin (IL)-6, -8, or -17, tumor necrosis factor-alpha (TNF-alpha), and Interferon-gamma (IFN-gamma), or a combination of TNF-alpha and IFN-gamma, or IFN-gamma and IL-17, for 1, 6, 24, or 48 h. Presence of receptors for these mediators was verified by RT-PCR. Effects of the cytokines on expression levels of MUC1 and -16 were determined by real-time PCR, and on mucin protein biosynthesis and ectodomain release in cell lysates and culture media, respectively, by immunoblot analysis. TNF-alpha and IFN-gamma each significantly induced MUC1 expression, cellular protein content and ectodomain release over time. Combined treatment with the two cytokines was not additive. By comparison, one of the inflammatory mediators, IFN-gamma, affected all three parameters-gene expression, cellular protein, and ectodomain release-for MUC16. Combined treatment with TNF-alpha and IFN-gamma showed effects similar to IFN-gamma alone, except that ectodomain release followed that of TNF-alpha, which induced MUC16 ectodomain release. In conclusion, inflammatory mediators present in tears of dry eye patients can affect MUC1 and -16 on corneal epithelial cells and may be responsible for alterations of surface mucins in dry eye.

FcepsilonRI-alpha siRNA inhibits the antigen-induced activation of mast cells.

PubMed

Safaralizadeh, Reza; Soheili, Zahra-Soheila; Deezagi, Abdolkhaleg; Pourpak, Zahra; Samiei, Shahram; Moin, Mostafa

2009-12-01

FcepsilonRI, The high affinity receptor for IgE plays a critical role in triggering the allergic reactions. It is responsible for inducing mast cell degranulation and deliberation of allergy mediators when it is aggregated by allergen and IgE complexes. FcepsilonRI on the mast cells consists of three subunits; alpha chain directly binds IgE, beta chain and dimmer of gamma chains together mediate intracellular signaling. Cross-linking of IgE-bound FcepsilonRI on the surface of mast cells and basophils by the multivalent antigen induces release of chemical mediators. The present in vitro study was designed to investigate the effect of synthetic FcepsilonRI-alpha siRNA on the antigen-induced activation of MC/9 cells. MC/9 cells which are murine mast cells were transfected by FcepsilonRI-alpha siRNA and negative control siRNA. After 6 h, anti-DNP (Dinitrophenyl) IgE was used for the cells sensitization. Then the cells were challenged with Dinitrophenyl-Human Serum Albumin (DNP-HSA) for mast cell degranulation induction before collection of supernatants. The amount of mRNA and protein expression was measured by Real Time PCR and western blot analysis, respectively. Determination of the expression rate of FcepsilonRI-alpha on cell surface was achieved by flow cytometry. ELISA and spectrophotometry methods were used subsequently for measuring the effects of FcepsilonRI-alpha siRNA on antigen-induced histamine and beta-hexosaminidase release. FcepsilonRI-alpha siRNA treated cells showed significant decrease in FcepsilonRI-alpha mRNA and protein expression in comparison to control cells. FcepsilonRI-mediated mast cell release of beta-hexosaminidase and histamine were also inhibited. In this study it was shown that FcepsilonRI-alpha siRNA could suppress FcepsilonRI-alpha expression and inhibited degranulation and histamine release in antigen-stimulated MC/9 cells. In conclusion, knock-down of FcepsilonRI-alpha by siRNA could be a promising method for inhibition of the mast cell-mediated allergic reactions.

Stochastic simulation of radium-223 dichloride therapy at the sub-cellular level

NASA Astrophysics Data System (ADS)

Gholami, Y.; Zhu, X.; Fulton, R.; Meikle, S.; El-Fakhri, G.; Kuncic, Z.

2015-08-01

Radium-223 dichloride (223Ra) is an alpha particle emitter and a natural bone-seeking radionuclide that is currently used for treating osteoblastic bone metastases associated with prostate cancer. The stochastic nature of alpha emission, hits and energy deposition poses some challenges for estimating radiation damage. In this paper we investigate the distribution of hits to cells by multiple alpha particles corresponding to a typical clinically delivered dose using a Monte Carlo model to simulate the stochastic effects. The number of hits and dose deposition were recorded in the cytoplasm and nucleus of each cell. Alpha particle tracks were also visualized. We found that the stochastic variation in dose deposited in cell nuclei (≃ 40%) can be attributed in part to the variation in LET with pathlength. We also found that ≃ 18% of cell nuclei receive less than one sigma below the average dose per cell (≃ 15.4 Gy). One possible implication of this is that the efficacy of cell kill in alpha particle therapy need not rely solely on ionization clustering on DNA but possibly also on indirect DNA damage through the production of free radicals and ensuing intracellular signaling.

RADIOACTIVITY IN TEXAS STREAMS

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

Drynan, W.R.; Gloyna, E.F.; Smallhorst, D.F.

1961-07-01

Early results from a 3-year program to collect base-line data on radioactivity in Texas waters are reported. When preliminary teste indicate the presence of significant quantities of either alpha or beta emitters, a gamma spectrum and a radiochemical separation of Sr and Ra is made. The instruments most frequently used in counting river samples are of the proportional gas flow type. Most of the samples collected throughout the state had less than 50 mu mu c/l of beta activity and 10 mu mu c/l of alpha activity. Tables are given of the gross radioactivity analyses of samples from the Canadianmore » and Neches Rivers in Texas along with the dates the samples were collected. (P.C.H.)« less

Physical Conditions of the Interstellar Medium in Star-forming Galaxies at z1.5

NASA Technical Reports Server (NTRS)

Hayashi, Masao; Ly, Chun; Shimasaku, Kazuhiro; Motohara, Kentaro; Malkan, Matthew A.; Nagao, Tohru; Kashikawa, Nobunari; Goto, Ryosuke; Naito, Yoshiaki

2015-01-01

We present results from Subaru/FMOS near-infrared (NIR) spectroscopy of 118 star-forming galaxies at z approximately equal to 1.5 in the Subaru Deep Field. These galaxies are selected as [O II] lambda 3727 emitters at z approximately equal to 1.47 and 1.62 from narrow-band imaging. We detect H alpha emission line in 115 galaxies, [O III] lambda 5007 emission line in 45 galaxies, and H Beta, [N II] lambda 6584, and [S II]lambda lambda 6716, 6731 in 13, 16, and 6 galaxies, respectively. Including the [O II] emission line, we use the six strong nebular emission lines in the individual and composite rest-frame optical spectra to investigate physical conditions of the interstellar medium in star-forming galaxies at z approximately equal to 1.5. We find a tight correlation between H alpha and [O II], which suggests that [O II] can be a good star formation rate (SFR) indicator for galaxies at z approximately equal to 1.5. The line ratios of H alpha / [O II] are consistent with those of local galaxies. We also find that [O II] emitters have strong [O III] emission lines. The [O III]/[O II] ratios are larger than normal star-forming galaxies in the local Universe, suggesting a higher ionization parameter. Less massive galaxies have larger [O III]/[O II] ratios. With evidence that the electron density is consistent with local galaxies, the high ionization of galaxies at high redshifts may be attributed to a harder radiation field by a young stellar population and/or an increase in the number of ionizing photons from each massive star.

Thermal Optical Properties of Lunar Dust Simulants and Their Constituents

NASA Technical Reports Server (NTRS)

Gaier, James R.; Ellis, Shaneise; Hanks, Nichole

2011-01-01

The total reflectance spectra of lunar simulant dusts (less than 20 micrometer particles) were measured in order to determine their integrated solar absorptance (alpha) and their thermal emittance (e) for the purpose of analyzing the effect of dust on the performance of thermal control surfaces. All of the simulants except one had a wavelength-dependant reflectivity (p(lambda)) near 0.10 over the wavelength range of 8 to 25 micrometers, and so are highly emitting at room temperature and lower. The 300 K emittance (epsilon) of all the lunar simulants except one ranged from 0.78 to 0.92. The exception was Minnesota Lunar Simulant 1 (MLS-1), which has little or no glassy component. In all cases the epsilon was lower for the less 20 micrometer particles than for larger particles reported earlier. There was considerably more variation in the lunar simulant reflectance in the solar spectral range (250 to 2500 nanometers) than in the thermal infrared. As expected, the lunar highlands simulants were more reflective in this wavelength range than the lunar mare simulants. The integrated solar absorptance (alpha) of the simulants ranged from 0.39 to 0.75. This is lower than values reported earlier for larger particles of the same simulants (0.41 to 0.82), and for representative mare and highlands lunar soils (0.74 to 0.91). Since the alpha of some mare simulants more closely matched that of highlands lunar soils, it is recommended that and values be the criteria for choosing a simulant for assessing the effects of dust on thermal control surfaces, rather than whether a simulant has been formulated as a highlands or a mare simulant.

Silicon Carbide Radioisotope Batteries

NASA Technical Reports Server (NTRS)

Rybicki, George C.

2005-01-01

The substantial radiation resistance and large bandgap of SiC semiconductor materials makes them an attractive candidate for application in a high efficiency, long life radioisotope battery. To evaluate their potential in this application, simulated batteries were constructed using SiC diodes and the alpha particle emitter Americium Am-241 or the beta particle emitter Promethium Pm-147. The Am-241 based battery showed high initial power output and an initial conversion efficiency of approximately 16%, but the power output decayed 52% in 500 hours due to radiation damage. In contrast the Pm-147 based battery showed a similar power output level and an initial conversion efficiency of approximately 0.6%, but no degradation was observed in 500 hours. However, the Pm-147 battery required approximately 1000 times the particle fluence as the Am-242 battery to achieve a similar power output. The advantages and disadvantages of each type of battery and suggestions for future improvements will be discussed.

Recent advances on organic blue thermally activated delayed fluorescence (TADF) emitters for organic light-emitting diodes (OLEDs)

PubMed Central

Bui, Thanh-Tuân; Goubard, Fabrice; Ibrahim-Ouali, Malika; Gigmes, Didier

2018-01-01

The design of highly emissive and stable blue emitters for organic light emitting diodes (OLEDs) is still a challenge, justifying the intense research activity of the scientific community in this field. Recently, a great deal of interest has been devoted to the elaboration of emitters exhibiting a thermally activated delayed fluorescence (TADF). By a specific molecular design consisting into a minimal overlap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) due to a spatial separation of the electron-donating and the electron-releasing parts, luminescent materials exhibiting small S1–T1 energy splitting could be obtained, enabling to thermally upconvert the electrons from the triplet to the singlet excited states by reverse intersystem crossing (RISC). By harvesting both singlet and triplet excitons for light emission, OLEDs competing and sometimes overcoming the performance of phosphorescence-based OLEDs could be fabricated, justifying the interest for this new family of materials massively popularized by Chihaya Adachi since 2012. In this review, we proposed to focus on the recent advances in the molecular design of blue TADF emitters for OLEDs during the last few years. PMID:29507635

The nature of H α-selected galaxies along the large-scale structure at z = 0.4 revealed by Subaru Hyper Suprime-Cam survey

NASA Astrophysics Data System (ADS)

Koyama, Yusei; Hayashi, Masao; Tanaka, Masayuki; Kodama, Tadayuki; Shimakawa, Rhythm; Yamamoto, Moegi; Nakata, Fumiaki; Tanaka, Ichi; Suzuki, Tomoko L.; Tadaki, Ken-ichi; Nishizawa, Atsushi J.; Yabe, Kiyoto; Toba, Yoshiki; Lin, Lihwai; Jian, Hung-Yu; Komiyama, Yutaka

2018-01-01

We present the environmental dependence of color, stellar mass, and star formation (SF) activity in Hα-selected galaxies along the large-scale structure at z = 0.4 hosting twin clusters in the DEEP2-3 field, discovered by the Subaru Strategic Program of Hyper Suprime-Cam (HSC SSP). By combining photo-z-selected galaxies and Hα emitters selected with broadband and narrowband (NB) data from the recent data release of HSC SSP (DR1), we confirm that galaxies in higher-density environments or galaxies in cluster central regions show redder colors. We find that there still remains a possible color-density and color-radius correlation even if we restrict the sample to Hα-selected galaxies, probably due to the presence of massive Hα emitters in denser regions. We also find a hint of increased star formation rates (SFR) amongst Hα emitters toward the highest-density environment, again primarily driven by the excess of red/massive Hα emitters in high-density environments, while their specific SFRs do not significantly change with environment. This work demonstrates the power of the HSC SSP NB data for studying SF galaxies across environments in the distant universe.

Beta/gamma and alpha backgrounds in CRESST-II Phase 2

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

Strauss, R.; Angloher, G.; Ferreiro Iachellini, N.

2015-06-01

The experiment CRESST-II aims at the detection of dark matter with scintillating CaWO{sub 4} crystals operated as cryogenic detectors. Recent results on spin-independent WIMP-nucleon scattering from the CRESST-II Phase 2 allowed to probe a new region of parameter space for WIMP masses below 3 GeV/c{sup 2}. This sensitivity was achieved after background levels were reduced significantly. We present extensive background studies of a CaWO{sub 4} crystal, called TUM40, grown at the Technische Universität München. The average beta/gamma rate of 3.51/[kg keV day] (1-40 keV) and the total intrinsic alpha activity from natural decay chains of 3.08±0.04 mBq/kg are the lowestmore » reported for CaWO{sub 4} detectors. Contributions from cosmogenic activation, surface-alpha decays, external radiation and intrinsic alpha/beta emitters are investigated in detail. A Monte-Carlo based background decomposition allows to identify the origin of the majority of beta/gamma events in the energy region relevant for dark matter search.« less

Dexamethasone antagonizes IL-4 and IL-10-induced release of IL-1RA by monocytes but augments IL-4-, IL-10-, and TGF-beta-induced suppression of TNF-alpha release.

PubMed

Joyce, D A; Steer, J H; Kloda, A

1996-07-01

The activities of monocyte-derived tumor necrosis factor (TNF)-alpha and interleukin (IL)-1 beta are potentially modified by IL-1RA and soluble receptors for TNF (sTNF-R), which are themselves monocyte products. IL-4, IL-10, TGF-beta, and glucocorticoids (GC) all suppress the lipopolysaccharide (LPS)-stimulated release of TNF-alpha and IL-1beta but vary in their effects on IL-1RA and sTNF-R. This raises the prospect of interactions between the cytokines and glucocorticoids, which may be antagonistic or additive on IL-1 and TNF activity. We, therefore, studied the interactions of the GC dexamethasone (Dex) with IL-4, IL-10, and transforming growth factor (TGF)-beta on the release of TNF-alpha and IL-1RA by human monocytes and the monocytic THP-1 cell line. Low concentration of Dex (10(-8)-10(-7)M) acted additively with low concentrations of IL-4 (0.01-1 ng/ml), IL-10 (0.01-0.1 U/ml), or TGF-beta (0.01-1 ng/ml) to profoundly suppress LPS-stimulated release of TNF-alpha by whole blood and, to a lesser degree, THP-1 cells. Dex also suppressed spontaneous release of IL-1RA from PBMC and THP-1 cells, whereas IL-4 and IL-10, but not TGF-beta, stimulated release. Dex antagonized the enhanced release in IL-4 and IL-10-stimulated cultures. The capacity to stimulate release of IL-1RA may contribute to the anti-inflammatory potential of IL-4 and IL-10 in monocyte/macrophage-mediated disease. GC, therefore, do not uniquely enhance the suppressive functions of IL-4 and IL-10 on monokine activity. The therapeutic benefit of combinations of GC and IL-4, IL-10 or TGF-beta in disease may depend on the roles of the individual monokines and antagonists in pathogenesis.

21 CFR 866.5080 - Alpha-1-antichymotrypsin immunological test system.

Code of Federal Regulations, 2011 CFR

2011-04-01

... immunochemical techniques alpha-1-antichymotrypsin (a protein) in serum, other body fluids, and tissues. Alpha-1-antichymotrypsin helps protect tissues against proteolytic (protein-splitting) enzymes released during infection...

Radionuclide injury to the lung.

PubMed Central

Dagle, G E; Sanders, C L

1984-01-01

Radionuclide injury to the lung has been studied in rats, hamsters, dogs, mice and baboons. Exposure of the lung to high dose levels of radionuclides produces a spectrum of progressively more severe functional and morphological changes, ranging from radiation pneumonitis and fibrosis to lung tumors. These changes are somewhat similar for different species. Their severity can be related to the absorbed radiation dose (measured in rads) produced by alpha, beta or gamma radiation emanating from various deposited radionuclides. The chemicophysical forms of radionuclides and spatial-temporal factors are also important variables. As with other forms of injury to the lung, repair attempts are highlighted by fibrosis and proliferation of pulmonary epithelium. Lung tumors are the principal late effect observed in experimental animals following pulmonary deposition of radionuclides at dose levels that do not result in early deaths from radiation pneumonitis or fibrosis. The predominant lung tumors described have been of epithelial origin and have been classified, in decreasing frequency of occurrence, as adenocarcinoma, bronchioloalveolar carcinoma, epidermoid carcinomas and combined epidermoid and adenocarcinoma. Mesothelioma and fibrosarcoma have been observed in rats, but less commonly in other species. Hemangiosarcomas were frequency observed in dogs exposed to beta-gamma emitters, and occasionally in rats exposed to alpha emitters. These morphologic changes in the lungs of experimental animals were reviewed and issues relevant to the prediction of human hazards discussed. PMID:6376095

Exploring the Structure of the Distant Universe with MUSE Data Cubes

NASA Astrophysics Data System (ADS)

MacDougall, Mason; Christensen, Lise

2018-01-01

The mass distribution in intergalactic and circumgalactic space is not well known since it is difficult to characterize objects in the distant universe. An ideal tool for studying such distant structure is the Multi-Unit Spectroscopic Explorer (MUSE) of the Very Large Telescope array, which employs a wide field-of-view and a large spectral range to produce high spatial resolution datasets. Here we exploit the 2 spatial dimensions and 1 spectral dimension of a particular MUSE “data cube” to identify and characterize emission line sources near the line-of-sight to quasar PKS1937-101, which lies at a redshift of z=3.787. In particular, we search for galaxy companions to a z=3.572 Lyman-limit system measured in the quasar spectrum and find an associated Lyman-alpha emitter at z=3.556 with a projected distance of 30.2 kpc from the quasar line-of-sight. Through a combination of automated source extraction and manual investigation, we also identify 25 emission line galaxies and 1 other Lyman-alpha emitter in our field. The proximity of several of these objects to the quasar line-of-sight allows us to reliably identify absorption lines in the quasar spectrum that can be associated with observed emission lines with resolved fluxes. This will help characterize the metallicities and kinematics of galaxy halos and circumgalactic media in the early universe.

Fission products and nuclear fuel behaviour under severe accident conditions part 3: Speciation of fission products in the VERDON-1 sample

NASA Astrophysics Data System (ADS)

Le Gall, C.; Geiger, E.; Gallais-During, A.; Pontillon, Y.; Lamontagne, J.; Hanus, E.; Ducros, G.

2017-11-01

Qualitative and quantitative analyses on the VERDON-1 sample made it possible to obtain valuable information on fission product behaviour in the fuel during the test. A promising methodology based on the quantitative results of post-test characterisations has been implemented to assess the release fraction of non γ-emitter fission products. The order of magnitude of the estimated release fractions for each fission product was consistent with their class of volatility.

Evolution of spent nuclear fuel in dry storage conditions for millennia and beyond

NASA Astrophysics Data System (ADS)

Wiss, Thierry; Hiernaut, Jean-Pol; Roudil, Danièle; Colle, Jean-Yves; Maugeri, Emilio; Talip, Zeynep; Janssen, Arne; Rondinella, Vincenzo; Konings, Rudy J. M.; Matzke, Hans-Joachim; Weber, William J.

2014-08-01

Significant amounts of spent uranium dioxide nuclear fuel are accumulating worldwide from decades of commercial nuclear power production. While such spent fuel is intended to be reprocessed or disposed in geologic repositories, out-of-reactor radiation damage from alpha decay can be detrimental to its structural stability. Here we report on an experimental study in which radiation damage in plutonium dioxide, uranium dioxide samples doped with short-lived alpha-emitters and urano-thorianite minerals have been characterized by XRD, transmission electron microscopy, thermal desorption spectrometry and hardness measurements to assess the long-term stability of spent nuclear fuel to substantial alpha-decay doses. Defect accumulation is predicted to result in swelling of the atomic structure and decrease in fracture toughness; whereas, the accumulation of helium will produce bubbles that result in much larger gaseous-induced swelling that substantially increases the stresses in the constrained spent fuel. Based on these results, the radiation-ageing of highly-aged spent nuclear fuel over more than 10,000 years is predicted.

Discovery and observation of BY Draconis variables

NASA Astrophysics Data System (ADS)

Bopp, B. W.; Noah, P. V.; Klimke, A.; Africano, J.

1981-10-01

The discovery of BY Draconis variables was efficiently accomplished by a spectroscopic survey of dK-M stars for weak H-alpha emissions, using 1-2 A resolution. The four BY Dra variables discovered are all spectroscopic binaries with P values lower than about 10 d, in light of which, it is noted that the onset of high surface activity and appearance of H-alpha emission occur sharply at v(equator) of approximately 5 km/sec. At v(equator) of about 3 km/sec, dK-M stars have low levels of surface activity. It is found that while there is a range of Ca II emission strength, and only the strongest emitters of this line are BY Dra and/or flare stars, the H-alpha feature changes abruptly to an emission feature signaling the onset of flaring and/or the BY Dra syndrome. An increase of the rotation rate above v(equator) 5 km/sec does not appear to increase the level of surface activity.

Interaction of a chick skin collagen fragment (alpha1-CB5) with human platelets. Biochemical studies during the aggregation and release reaction.

PubMed

Chiang, T M; Beachey, E H; Kang, A H

1975-09-10

The denatured alpha1(I) chain and the cyanogen bromide peptide, alpha1(I)-CB5, of chick skin collagen cause the release of serotonin and leakage of lactic dehydrogenase from human platelets in a manner similar to the release reaction mediated by adenosine diphosphate and native collagen. These peptides also cause a decrease in the level of adenosine 3':5'-monophosphate (cAMP) in platelets. Adenylate cyclase activity of platelets is partially inhibited by these peptides as well as by native collagen, ADP, and epinephrine, but cAMP phosphodiesterase activity is unaltered by these substances. In contrast, the level of platelet guanosine 3':5'-monophosphate (cGMP) is increased by the collagen peptides as well as the other aggregating agents. The increase is associated with increased guanylate cyclase, but normal cGMP phosphodiesterase activities of platelets. Optical rotatory and viscometric measurements of the alpha1 chains and alpha1-CB5 of chick skin in 0.01 M phosphate/0.15 M sodium chloride, pH 7.4, at various temperatures as a function of time indicate that no detectable renaturation occurs at 37 degrees for at least 30 min of observation. Molecular sieve chromatography of alpha1-CB5 in the phosphate buffer at 37 degrees shows that its elution position is identical to that performed under denaturing conditions (at 45 degrees) with no evidence of higher molecular weight aggregates, and the alpha1-CB5 glycopeptide fraction eluting from the column at the position of its monomer retains the platelet aggregating activity. Additionally, electron microscopic examination of the platelet-rich plasma that had been reacted with these peptides fail to show any ordered collagen structures. These data indicate that the denatured alpha1 chain and alpha1-CB5 glycopeptide of chick skin collagen mediate platelet aggregation through the "physiologic" release reaction in a manner similar to that induced by other aggregating agents such as ADP, epinephrine, or native collagen, and support the conclusion that the aggregating activity of the alpha1 chain and alpha1-CB5 is not likely to be due to the formation of polymerized products.

Tumor necrosis factor-inducing activities of Cryptococcus neoformans components.

PubMed Central

Delfino, D; Cianci, L; Migliardo, M; Mancuso, G; Cusumano, V; Corradini, C; Teti, G

1996-01-01

Cryptococcus neoformans-induced tumor necrosis factor alpha (TNF-alpha) production may lead to increased human immunodeficiency virus replication in patients with AIDS. In order to identify cryptococcal components that are predominantly responsible for stimulating TNF production, various concentrations of glucuronoxylomannan (GXM), galactoxylomannan (GalXM), mannoproteins (MP), and alpha(1-3) [corrected] glucan were added to whole-blood cultures. All of the cryptococcal components tested, as well as whole heat-killed cryptococci, were capable of inducing TNF-alpha release in a dose-dependent manner. MP were significantly more potent than any of the other cryptococcal components tested or heat-killed cryptococci in stimulating TNF-alpha production (P < 0.05). GXM, in contrast, was significantly less potent in this activity than either GalXM or MP (P < 0.05). As little as 0.5 microg of MP per ml was sufficient to produce moderate but significant elevations of TNF-alpha release. Maximal MP-induced TNF-alpha levels were similar to those induced by Salmonella enteritidis lipopolysaccharide, our positive control. Further experiments using isolated leukocytes suggested that monocytes were the cell population mainly responsible for TNF-alpha production, although the participation of other cell types could not be excluded. The presence of complement-sufficient plasma was a necessary requirement for TNF-alpha induction by GXM, GalXM, and low doses of MP. High MP concentrations (100 microg/ml) were also capable of stimulating TNF-alpha production in the absence of plasma. These data indicate that soluble products released by C. neoformans are capable of inducing TNF-alpha secretion in human leukocytes. This may be clinically relevant, since high concentrations of such products are frequently found in the body fluids of AIDS patients infected with C. neoformans. PMID:8945566

Anthropogenic Methane Emissions in California's San Joaquin Valley: Characterizing Large Point Source Emitters

NASA Astrophysics Data System (ADS)

Hopkins, F. M.; Duren, R. M.; Miller, C. E.; Aubrey, A. D.; Falk, M.; Holland, L.; Hook, S. J.; Hulley, G. C.; Johnson, W. R.; Kuai, L.; Kuwayama, T.; Lin, J. C.; Thorpe, A. K.; Worden, J. R.; Lauvaux, T.; Jeong, S.; Fischer, M. L.

2015-12-01

Methane is an important atmospheric pollutant that contributes to global warming and tropospheric ozone production. Methane mitigation could reduce near term climate change and improve air quality, but is hindered by a lack of knowledge of anthropogenic methane sources. Recent work has shown that methane emissions are not evenly distributed in space, or across emission sources, suggesting that a large fraction of anthropogenic methane comes from a few "super-emitters." We studied the distribution of super-emitters in California's southern San Joaquin Valley, where elevated levels of atmospheric CH4 have also been observed from space. Here, we define super-emitters as methane plumes that could be reliably detected (i.e., plume observed more than once in the same location) under varying wind conditions by airborne thermal infrared remote sensing. The detection limit for this technique was determined to be 4.5 kg CH4 h-1 by a controlled release experiment, corresponding to column methane enhancement at the point of emissions greater than 20% above local background levels. We surveyed a major oil production field, and an area with a high concentration of large dairies using a variety of airborne and ground-based measurements. Repeated airborne surveys (n=4) with the Hyperspectral Thermal Emission Spectrometer revealed 28 persistent methane plumes emanating from oil field infrastructure, including tanks, wells, and processing facilities. The likelihood that a given source type was a super-emitter varied from roughly 1/3 for processing facilities to 1/3000 for oil wells. 11 persistent plumes were detected in the dairy area, and all were associated with wet manure management. The majority (11/14) of manure lagoons in the study area were super-emitters. Comparing to a California methane emissions inventory for the surveyed areas, we estimate that super-emitters comprise a minimum of 9% of inventoried dairy emissions, and 13% of inventoried oil emissions in this region.

Interaction with extracellular matrix proteins influences Lsh/Ity/Bcg (candidate Nramp) gene regulation of macrophage priming/activation for tumour necrosis factor-alpha and nitrite release.

PubMed

Formica, S; Roach, T I; Blackwell, J M

1994-05-01

The murine resistance gene Lsh/Ity/Bcg regulates activation of macrophages for tumour necrosis factor-alpha (TNF-alpha)-dependent production of nitric oxide mediating antimicrobial activity against Leishmania, Salmonella and Mycobacterium. As Lsh is differentially expressed in macrophages from different tissue sites, experiments were performed to determine whether interaction with extracellular matrix (ECM) proteins would influence the macrophage TNF-alpha response. Plating of bone marrow-derived macrophages onto purified fibrinogen or fibronectin-rich L929 cell-derived matrices, but not onto mannan, was itself sufficient to stimulate TNF-alpha release, with significantly higher levels released from congenic B10.L-Lshr compared to C57BL/10ScSn (Lshs) macrophages. Only macrophages plated onto fibrinogen also released measurable levels of nitrites, again higher in Lshr compared to Lshs macrophages. Addition of interferon-gamma (IFN-gamma), but not bacterial lipopolysaccharide or mycobacterial lipoarabinomannan, as a second signal enhanced the TNF-alpha and nitrite responses of macrophages plated onto fibrinogen, particularly in the Lshr macrophages. Interaction with fibrinogen and fibronectin also primed macrophages for an enhanced TNF-alpha response to leishmanial parasites, but this was only translated into enhanced nitrite responses in the presence of IFN-gamma. In these experiments, Lshr macrophages remained superior in their TNF-alpha responses throughout, but to a degree which reflected the magnitude of the difference observed on ECM alone. Hence, the specificity for the enhanced TNF-alpha responses of Lshr macrophages lay in their interaction with fibrinogen and fibronectin ECM, while a differential nitrite response was only observed with fibrinogen and/or IFN-gamma. The results are discussed in relation to the possible function of the recently cloned candidate gene Nramp, which has structural identity to eukaryote transporters and an N-terminal cytoplasmic proline/serine-rich putative SH3 binding domain.

1973 environmental monitoring report

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

Hull, A.P.; Ash, J.A.

1974-03-01

>Results from radiation monitoring during 1973 in the environment of the Brookhaven National Laboratory are presented. Data are included on: the gross alpha and BETA activity and content of tritium and gamma-emitting radionuclides in surface air; gross BETA activity and gamma and tritium content in atmospheric precipitation; activities and concentration of gamma emitters in liquid effiuents and ground water; gross BETA , tritium and /sup 90/Sr in effluents; gross BETA and tritl um in surface waters; /sup 90/Sr and gamma- emitting radionuclides in river ecosystem; gross alpha , gross BETA , tritium, / sup 90/Sr, and /sup 137/Cs in groundmore » and well water; /sup 137/Cs, K, /sup 131/I, and /sup 90/Sr content in area milk; and gamma-emitting radionuclides in soils and grasses. (LCL)« less

Plasma effects on the passive external thermal control coating of Space Station Freedom

NASA Technical Reports Server (NTRS)

Carruth, Ralph, Jr.; Vaughn, Jason A.; Holt, James M.; Werp, Richard; Sudduth, Richard D.

1992-01-01

The current baseline chromic acid anodized thermal control coating on 6061-T6 aluminum meteoroid debris (M/D) shields for SSF has been evaluated. The degradation of the solar absorptance, alpha, and the thermal emittance, epsilon, of chromic acid anodized aluminum due to dielectric breakdown in plasma was measured to predict the on-orbit lifetime of the SSF M/D shields. The lifetime of the thermal control coating was based on the surface temperatures achieved with degradation of the thermal control properties, alpha and epsilon. The temperatures of each M/D shield from first element launch (FEL) through FEL+15 years were analyzed. It is shown that the baseline thermal control coating cannot withstand the -140 V potential between the conductive structure of the SSF and the current plasma environment.

Radiotoxicity of Gadolinium-148 and Radium-223 in Mouse Testes: Relative Biological Effectiveness of Alpha-Particle Emitters In Vivo

PubMed Central

Howell, Roger W.; Goddu, S. Murty; Narra, Venkat R.; Fisher, Darrell R.; Schenter, Robert E.; Rao, Dandamudi V.

2012-01-01

The biological effects of radionuclides that emit α particles are of considerable interest in view of their potential for therapy and their presence in the environment. The present work is a continuation of our ongoing effort to study the radiotoxicity of α-particle emitters in vivo using the survival of murine testicular sperm heads as the biological end point. Specifically, the relative biological effectiveness (RBE) of very low-energy α particles (3.2 MeV) emitted by 148Gd is investigated and determined to be 7.4 ± 2.4 when compared to the effects of acute external 120 kVp X rays. This datum, in conjunction with our earlier results for 210Po and 212Pb in equilibrium with its daughters, is used to revise and extend the range of validity of our previous RBE–energy relationship for α particles emitted by tissue-incorporated radionuclides. The new empirical relationship is given by RBEα = 9.14 − 0.510 Eα, where 3 < Eα < 9 MeV. The validity of this empirical relationship is tested by determining the RBE of the prolific α-particle emitter 223Ra (in equilibrium with its daughters) experimentally in the same biological model and comparing the value obtained experimentally with the predicted value. The resulting RBE values are 5.4 ± 0.9 and 5.6, respectively. This close agreement strongly supports the adequacy of the empirical RBE-Eα relationship to predict the biological effects of α-particle emitters in Vivo. PMID:9052681

Radioligand therapy of metastatic castration-resistant prostate cancer: current approaches.

PubMed

Awang, Zool Hilmi; Essler, Markus; Ahmadzadehfar, Hojjat

2018-05-23

Prostate Cancer is the forth most common type of cancer. Prostate-specific membrane antigen (PSMA) is anchored in the cell membrane of prostate epithelial cells. PSMA is highly expressed on prostate epithelial cells and strongly up-regulated in prostate cancer. Therefore it is an appropriate target for diagnostic and therapy of prostate cancer and its metastases. This article discusses several articles on radionuclide treatments in prostate cancer and the results on PSMA therapy with either beta or alpha emitters as a salvage therapy.

Review of technical justification of assumptions and methods used by the Environmental Protection Agency for estimating risks avoided by implementing MCLs for radionuclides

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

Morris, S.C.; Rowe, M.D.; Holtzman, S.

1992-11-01

The Environmental Protection Agency (EPA) has proposed regulations for allowable levels of radioactive material in drinking water (40 CFR Part 141, 56 FR 33050, July 18, 1991). This review examined the assumptions and methods used by EPA in calculating risks that would be avoided by implementing the proposed Maximum Contaminant Levels for uranium, radium, and radon. Proposed limits on gross alpha and beta-gamma emitters were not included in this review.

FEMOS - Advanced Neutron Monitor System for Waste Management

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

Simon, G.G.; Sokcic-Kostic, M.

2006-07-01

FEMOS is a specially developed monitor to detect fissile materials for waste characterisation and it is also suitable to identify the main neutron emitters. The latest measuring prototype is in routine operation at FZK-HDB (Germany) for determining Plutonium content and alpha activity in 2001 and 4001 drums from the reprocessing plant Karlsruhe (WAK). Authorities license the measurement procedure. Routine measurements conducted over a period of about 6 years and the results show that all specified prerequisites are met with the required reliability. (authors)

Rheology as a Tool to Predict the Release of Alpha-Lipoic Acid from Emulsions Used for the Prevention of Skin Aging

PubMed Central

Isaac, Vera Lucia Borges; Chiari-Andréo, Bruna Galdorfini; Marto, Joana Marques; Moraes, Jemima Daniela Dias; Leone, Beatriz Alves; Corrêa, Marcos Antonio; Ribeiro, Helena Margarida

2015-01-01

The availability of an active substance through the skin depends basically on two consecutive steps: the release of this substance from the vehicle and its subsequent permeation through the skin. Hence, studies on the specific properties of vehicles, such as their rheological behavior, are of great interest in the field of dermatological products. Recent studies have shown the influence of the rheological features of a vehicle on the release of drugs and active compounds from the formulation. In this context, the aim of this study was to evaluate the influence of the rheological features of two different emulsion formulations on the release of alpha-lipoic acid. Alpha-lipoic acid (ALA) was chosen for this study because of its antioxidant characteristics, which could be useful for the prevention of skin diseases and aging. The rheological and mechanical behavior and the in vitro release profile were assayed. The results showed that rheological features, such as viscosity, thixotropy, and compliance, strongly influenced the release of ALA from the emulsion and that the presence of a hydrophilic polymer in one of the emulsions was an important factor affecting the rheology and, therefore, the release of ALA. PMID:26788510

Nanozeolite bioconjugates labeled with 223Ra for targeted alpha therapy.

PubMed

Piotrowska, Agata; Męczyńska-Wielgosz, Sylwia; Majkowska-Pilip, Agnieszka; Koźmiński, Przemysław; Wójciuk, Grzegorz; Cędrowska, Edyta; Bruchertseifer, Frank; Morgenstern, Alfred; Kruszewski, Marcin; Bilewicz, Aleksander

2017-04-01

Alpha particle emitting isotopes are of considerable interest for radionuclide therapy because of their high cytotoxicity and short path length. Among the many α emitters, 223 Ra exhibits very attractive nuclear properties for application in radionuclide therapy. The decay of this radioisotope and its daughters is accompanied by the emission of four α-particles, releasing 27.9MeV of cumulative energy. Unfortunately the lack of an appropriate bifunctional ligand for radium has so far been a main obstacle for the application of 223 Ra in receptor targeted therapy. In our studies we investigated the use of nanozeolite-Substance P bioconjugates as vehicles for 223 Ra radionuclides for targeted α therapy. The sodium form of an A-type of nanozeolite (NaA) was synthesized using the template method. Next, the nanozeolite particles were conjugated to the Substance P (5-11) peptide fragment, which targets NK-1 receptors on glioma cells. The obtained bioconjugate was characterized by transmission emission spectroscopy, thermogravimetric analysis and dynamic light scattering analysis. The NaA-silane-PEG-SP(5-11) bioconjugates were labeled with 223 Ra by exchange of the Na + cation and the stability, receptor affinity and cytotoxicity of the obtained radiobioconjugates were tested. The 223 Ra-labeled nanozeolite bioconjugate almost quantitatively retains 223 Ra in vitro after 6days, while the retention of decay products varies from 90 to 95%. The synthesized 223 RaA-silane-PEG-SP(5-11) showed high receptor affinity toward NK-1 receptor expressing glioma cells and exhibited a high cytotoxic effect in vitro. Substance P functionalized nanozeolite-A represents a viable solution for the use of the 223 Ra in vivo generator as a therapeutic construct for targeting glioma cells. Copyright © 2016 Elsevier Inc. All rights reserved.

Characterization of noradrenaline release in the locus coeruleus of freely moving awake rats by in vivo microdialysis.

PubMed

Fernández-Pastor, Begoña; Mateo, Yolanda; Gómez-Urquijo, Sonia; Javier Meana, J

2005-07-01

The origin and regulation of noradrenaline (NA) in the locus coeruleus (LC) is unknown. The neurochemical features of NA overflow (nerve impulse dependence, neurotransmitter synthesis, vesicle storage, reuptake, alpha2-adrenoceptor-mediated regulation) were characterized in the LC. Brain microdialysis was performed in awake rats. Dialysates were analyzed for NA. NA in the LC decreased via local infusion of Ca2+-free medium (-42+/-5%) or the sodium channel blocker tetrodotoxine (TTX) (-47+/-8%) but increased (333+/-40%) via KCl-induced depolarization. The tyrosine hydroxylase (TH) inhibitor alpha-methyl-p-tyrosine (250 mg kg(-1), i.p.) and the vesicle depletory drug reserpine (5 mg kg(-1), i.p.) decreased NA. Therefore, extracellular NA in the LC satisfies the criteria for an impulse flow-dependent vesicular exocytosis of neuronal origin. Local perfusion of the alpha2-adrenoceptor agonist clonidine (0.1-100 microM) decreased NA (E(max)=-79+/-5%) in the LC, whereas the opposite effect (E(max)=268+/-53%) was observed with the alpha2A-adrenoceptor antagonist BRL44408 (0.1-100 microM). This suggests a tonic modulation of NA release through local alpha2A-adrenoceptors. The selective NA reuptake inhibitor desipramine (DMI) (0.1-100 microM) administered into the LC increased NA in the LC (E(max)=223+/-40%) and simultaneously decreased NA in the cingulate cortex, confirming the modulation exerted by NA in the LC on firing activity of noradrenergic cells and on the subsequent NA release in noradrenergic terminals. Synaptic processes underlying NA release in the LC are similar to those in noradrenergic terminal areas. NA in the LC could represent local somatodendritic release, but also the presence of neurotransmitter release from collateral axon terminals.

Defibrotide modulates prostaglandin production in the rat mesenteric vascular bed.

PubMed

Peredo, H A

2002-10-01

Defibrotide 1 microM, a polydeoxyribonucleotide extracted from mammalian organs, reduced the contractile responses to noradrenaline (NA) in the rat isolated and perfused mesenteric vascular bed, in intact as well as in de-endothelialized preparations. Defibrotide was without effect on the acetylcholine-induced relaxations of U-46619-precontracted mesenteric vascular beds. Moreover, defibrotide increased 6-keto prostaglandin (PG) F(2alpha) (stable metabolite of prostacyclin) release sixfold in the presence, but not in the absence of the endothelium, with no modification on the release of other prostanoids. Defibrotide also inhibited the NA-induced increase in PGF(2alpha) release, in both intact and de-endothelialized mesenteric vascular beds. In conclusion, the present results show that defibrotide modulates PG production in the mesenteric bed and that the observed inhibition of the contractile responses should be due to the impairment of the NA-induced increase in PGF(2alpha) release.

Effect of quench on alpha/beta pulse shape discrimination of liquid scintillation cocktails.

PubMed

DeVol, Timothy A; Theisen, Christopher D; DiPrete, David P

2007-05-01

The objectives of this paper are (1) to illustrate that knowledge of the external quench parameter is insufficient to properly setup a pulse shape discriminating liquid scintillation counter (LSC) for quantitative measurement, (2) to illustrate dependence on pulse shape discrimination on the radionuclide (more than just radiation and energy), and (3) to compare the pulse shape discrimination (PSD) of two commercial instruments. The effects various quenching agents, liquid scintillation cocktails, radionuclides, and LSCs have on alpha/beta pulse shape discriminating liquid scintillation counting were quantified. Alpha emitting radionuclides (239)Pu and (241)Am and beta emitter (90)Sr/(90)Y were investigated to quantify the nuclide dependence on alpha/beta pulse shape discrimination. Also, chemical and color quenching agents, nitromethane, nitric acid, and yellow dye impact on alpha/beta pulse shape discrimination using PerkinElmer Optiphase "HiSafe" 2 and 3, and Ultima Gold AB liquid scintillation cocktails were determined. The prepared samples were counted on the PerkinElmer Wallac WinSpectral 1414 alpha/beta pulse shape discriminating LSC. It was found that for the same level of quench, as measured by the external quench parameter, different quench agents influenced the pulse shape discrimination and the pulse shape discrimination parameters differently. The radionuclide also affects alpha/beta pulse shape discrimination. By comparison with the PerkinElmer Tri-carb 3150 TR/AB, the Wallac 1414 exhibited better pulse shape discrimination capability under the same experimental conditions.

Molecular Analysis of the Inheritance of Transcriptional Silencing

DTIC Science & Technology

2007-04-01

arrest, to synchronize the cells for hydroxyurea (HU) addition, and then released into an alpha factor/0.2M HU arrest (Fig. 1A). 2 hours after release...restrictive conditions to degrade both Sir1td and Asf1td proteins. Cells were then release for 4 hours into 0.2M hydroxyurea (HU), an early S phase arrest...on three experiments. The “Block” row describes the cell cycle inhibitor used in each time point (alpha factor, hydroxyurea and nocodozole). 24

Soluble antigens from group B streptococci induce cytokine production in human blood cultures.

PubMed Central

von Hunolstein, C; Totolian, A; Alfarone, G; Mancuso, G; Cusumano, V; Teti, G; Orefici, G

1997-01-01

Group B streptococcal antigens stimulated tumor necrosis factor alpha (TNF-alpha), interleukin-1 (IL-1), and IL-6 production in human blood cultures in a concentration- and time-dependent fashion. The minimal concentrations of type-specific polysaccharides, lipoteichoic acid, and group-specific polysaccharide required to produce these effects were, respectively, 0.01, 1, and 10 microg/ml. Cell separation experiments indicated that monocytes were the cell type mainly responsible for cytokine production. Time course studies indicated that TNF-alpha was released before the other cytokines. TNF-alpha, however, did not appear to directly induce IL-1beta, as shown by blockade experiments with anti-TNF-alpha antibodies. IL-6 levels were moderately but significantly decreased by anti-TNF-alpha. These data indicate that several products from group B streptococci are able to directly stimulate human monocytes to release TNF-alpha, IL-1beta, and IL-6. These findings may be clinically relevant, since proinflammatory cytokines can mediate pathophysiologic changes during sepsis. PMID:9317001

A K ATP channel-dependent pathway within alpha cells regulates glucagon release from both rodent and human islets of Langerhans.

PubMed

MacDonald, Patrick E; De Marinis, Yang Zhang; Ramracheya, Reshma; Salehi, Albert; Ma, Xiaosong; Johnson, Paul R V; Cox, Roger; Eliasson, Lena; Rorsman, Patrik

2007-06-01

Glucagon, secreted from pancreatic islet alpha cells, stimulates gluconeogenesis and liver glycogen breakdown. The mechanism regulating glucagon release is debated, and variously attributed to neuronal control, paracrine control by neighbouring beta cells, or to an intrinsic glucose sensing by the alpha cells themselves. We examined hormone secretion and Ca(2+) responses of alpha and beta cells within intact rodent and human islets. Glucose-dependent suppression of glucagon release persisted when paracrine GABA or Zn(2+) signalling was blocked, but was reversed by low concentrations (1-20 muM) of the ATP-sensitive K(+) (KATP) channel opener diazoxide, which had no effect on insulin release or beta cell responses. This effect was prevented by the KATP channel blocker tolbutamide (100 muM). Higher diazoxide concentrations (>/=30 muM) decreased glucagon and insulin secretion, and alpha- and beta-cell Ca(2+) responses, in parallel. In the absence of glucose, tolbutamide at low concentrations (<1 muM) stimulated glucagon secretion, whereas high concentrations (>10 muM) were inhibitory. In the presence of a maximally inhibitory concentration of tolbutamide (0.5 mM), glucose had no additional suppressive effect. Downstream of the KATP channel, inhibition of voltage-gated Na(+) (TTX) and N-type Ca(2+) channels (omega-conotoxin), but not L-type Ca(2+) channels (nifedipine), prevented glucagon secretion. Both the N-type Ca(2+) channels and alpha-cell exocytosis were inactivated at depolarised membrane potentials. Rodent and human glucagon secretion is regulated by an alpha-cell KATP channel-dependent mechanism. We propose that elevated glucose reduces electrical activity and exocytosis via depolarisation-induced inactivation of ion channels involved in action potential firing and secretion.

Drug discrimination and neurochemical studies in alpha7 null mutant mice: tests for the role of nicotinic alpha7 receptors in dopamine release.

PubMed

Quarta, Davide; Naylor, Christopher G; Barik, Jacques; Fernandes, Cathy; Wonnacott, Susan; Stolerman, Ian P

2009-04-01

The nicotine discriminative stimulus has been linked to beta2-containing (beta2*) nicotinic receptors, with little evidence of a role for alpha7 nicotinic receptors, because nicotine discrimination was very weak in beta2 null mutant mice but normal in alpha7 mutants. As both alpha7 and beta2* nicotinic receptors have been implicated in nicotine-stimulated dopamine overflow, this study focused on the dopamine-mediated element in the nicotine stimulus by examining cross-generalisation between amphetamine and nicotine. Male alpha7 nicotinic receptor null mutant mice and wild-type controls were bred in-house and trained to discriminate nicotine (0.8 mg/kg) or (+)-amphetamine (0.6 mg/kg) from saline in a two-lever procedure with a tandem VI-30 FR-10 schedule of food reinforcement. Dopamine release from striatal slices was determined in parallel experiments. An alpha7 nicotinic receptor-mediated component of dopamine release was demonstrated in tissue from wild-type mice using choline as a selective agonist. This response was absent in tissue from null mutant animals. The mutation did not influence acquisition of drug discriminations but subtly affected the results of cross-generalisation tests. In mice trained to discriminate nicotine or amphetamine, there was partial cross-generalisation in wild-type mice and, at certain doses, these effects were attenuated in mutants. Further support for an alpha7 nicotinic receptor-mediated component was provided by the ability of the alpha7 nicotinic receptor antagonist methyllycaconitine to attenuate responses to nicotine and amphetamine in wild-type mice. These findings support the concept of an alpha7 nicotinic receptor-mediated dopaminergic element in nicotine discrimination, warranting further tests with selective dopamine agonists.

The role of lipopolysaccharide in infectious bone resorption of periapical lesion.

PubMed

Hong, Chi-Yuan; Lin, Sze-Kwan; Kok, Sang-Heng; Cheng, Shih-Jung; Lee, Ming-Shu; Wang, Tong-Mei; Chen, Chuan-Shuo; Lin, Li-Deh; Wang, Juo-Song

2004-03-01

The role of lipopolysaccharide (LPS) in periapical lesion-induced bone resorption was investigated. Polymyxin B (PMB), a specific inhibitor of LPS, was evaluated to treat the apical lesion. Lipopolysaccharide isolated from two common endodontic pathogens, Fusobacterium nucleatum and Porphyromonas endodontalis, stimulated mouse macrophage (J774) to release interleukin-1alpha (IL-1 alpha) and tumor necrosis factor-alpha (TNF-alpha) in a time-dependent manner. Combination of LPS further enhanced the stimulation. PMB inhibited these effects significantly. LPS also stimulated matrix metalloproteinase-1 (MMP-1) gene expression in J774, whereas anti-IL-1 alpha and anti-TNF-alpha antibodies, as well as PMB, diminished this effect. A disease model of periapical lesion was established in Wistar rat. Administration of PMB reduced the extent of lesion-associated bone resorption by 76% to approximately 80%, and simultaneously reduced the numbers of MMP-1-producing macrophages. It is suggested that LPS released from the infected root canal triggers the synthesis of IL-1 alpha and TNF-alpha from macrophages. These pro-inflammatory cytokines up-regulate the production of MMP-1 by macrophages to promote periapical bone resorption.

Stability of zinc stearate under alpha irradiation in the manufacturing process of SFR nuclear fuels

NASA Astrophysics Data System (ADS)

Gracia, J.; Vermeulen, J.; Baux, D.; Sauvage, T.; Venault, L.; Audubert, F.; Colin, X.

2018-03-01

The manufacture of new fuels for sodium-cooled fast reactors (SFRs) will involve powders derived from recycling existing fuels in order to keep on producing electricity while saving natural resources and reducing the amount of waste produced by spent MOX fuels. Using recycled plutonium in this way will significantly increase the amount of 238Pu, a high energy alpha emitter, in the powders. The process of shaping powders by pressing requires the use of a solid lubricant, zinc stearate, to produce pellets with no defects compliant with the standards. The purpose of this study is to determine the impact of alpha radiolysis on this additive and its lubrication properties. Experiments were conducted on samples in contact with PuO2, as well as under external helium ion beam irradiation, in order to define the kinetics of radiolytic gas generation. The yield results relating to the formation of these gases (G0) show that the alpha radiation of plutonium can be simulated using external helium ion beam irradiation. The isotopic composition of plutonium has little impact on the yield. However, an increased yield was globally observed with increasing the mean linear energy transfer (LET). A radiolytic degradation process is proposed.

Lactococcin G is a potassium ion-conducting, two-component bacteriocin.

PubMed

Moll, G; Ubbink-Kok, T; Hildeng-Hauge, H; Nissen-Meyer, J; Nes, I F; Konings, W N; Driessen, A J

1996-02-01

Lactococcin G is a novel lactococcal bacteriocin whose activity depends on the complementary action of two peptides, termed alpha and beta. Peptide synthesis of the alpha and beta peptides yielded biologically active lactococcin G, which was used in mode-of-action studies on sensitive cells of Lactococcus lactis. Approximately equivalent amounts of both peptides were required for optimal bactericidal effect. No effect was observed with either the alpha or beta peptide in the absence of the complementary peptide. The combination of alpha and beta peptides (lactococcin G) dissipates the membrane potential (delta omega), and as a consequence cells release alpha-aminoisobutyrate, a non-metabolizable alanine analog that is accumulated through a proton motive-force dependent mechanism. In addition, the cellular ATP level is dramatically reduced, which results in a drastic decrease of the ATP-driven glutamate uptake. Lactococcin G does not form a proton-conducting pore, as it has no effect on the transmembrane pH gradient. Dissipation of the membrane potential by uncouplers causes a slow release of potassium (rubidium) ions. However, rapid release of potassium was observed in the presence of lactococcin G. These data suggest that the bactericidal effect of lactococcin G is due to the formation of potassium-selective channels by the alpha and beta peptides in the target bacterial membrane.

Hypoxia-inducible factor 1-alpha release after intracoronary versus intramyocardial stem cell therapy in myocardial infarction.

PubMed

Gyöngyösi, Mariann; Hemetsberger, Rayyan; Posa, Aniko; Charwat, Silvia; Pavo, Noemi; Petnehazy, Ors; Petrasi, Zsolt; Pavo, Imre J; Hemetsberger, Hani; Benedek, Imre; Benedek, Teodora; Benedek, Istvan; Kovacs, Istvan; Kaun, Christoph; Maurer, Gerald

2010-04-01

We have investigated the effect of stem cell delivery on the release of hypoxia-inducible factor 1 alpha (HIF-1alpha) in peripheral circulation and myocardium in experimental myocardial ischemia. Closed-chest, reperfused myocardial infarction (MI) was created in domestic pigs. Porcine mesenchymal stem cells (MSCs) were cultured and delivered (9.8 +/- 1.2 x 10(6)) either percutaneously NOGA-guided transendocardially (Group IM) or intracoronary (Group IC) 22 +/- 4 days post-MI. Pigs without MSC delivery served as sham control (Group S). Plasma HIF-1alpha was measured at baseline, immediately post- and at follow-up (FUP; 2 h or 24 h) post-MSC delivery by ELISA kit. Myocardial HIF-1alpha expression of infarcted, normal myocardium, or border zone was determined by Western blot. Plasma level of HIF-1alpha increased immediately post-MI (from 278 +/- 127 to 631 +/- 375 pg/ml, p < 0.05). Cardiac delivery of MSCs elevated the plasma levels of HIF-1alpha significantly (p < 0.05) in groups IC and IM immediately post-MSC delivery, and returned to baseline level at FUP, without difference between the groups IC and IM. The myocardial tissue HIF-1alpha expression in the infarcted area was higher in Group IM than in Group IC or S (1,963 +/- 586 vs. 1,307 +/- 392 vs. 271 +/- 110 activity per square millimeter, respectively, p < 0.05), while the border zone contained similarly lower level of HIF-1alpha, but still significantly higher as compared with Group S. Trend towards increase in myocardial expression of HIF-1alpha was measured in Group IM at 24 h, in contrast to Group IC. In conclusion, both stem cell delivery modes increase the systemic and myocardial level of HIF-1alpha. Intramyocardial delivery of MSC seems to trigger the release of angiogenic HIF-1alpha more effectively than does intracoronary delivery.

Hypothalamic interactions between neuropeptide Y, agouti-related protein, cocaine- and amphetamine-regulated transcript and alpha-melanocyte-stimulating hormone in vitro in male rats.

PubMed

Dhillo, W S; Small, C J; Stanley, S A; Jethwa, P H; Seal, L J; Murphy, K G; Ghatei, M A; Bloom, S R

2002-09-01

A number of neuropeptides implicated in the hypothalamic regulation of appetite are synthesized in the arcuate nucleus (Arc). Neuropeptide Y (NPY) and agouti-related protein (Agrp) are orexigenic. The pro-opiomelanocortin (POMC) product alpha-melanocyte-stimulating hormone (alpha-MSH) is anorectic. Intracerebroventricular administration of cocaine- and amphetamine-regulated transcript (CART) decreases food intake. However, recent results show that CART is orexigenic when injected into discrete hypothalamic nuclei. There is almost complete coexpression of NPY and Agrp mRNA in Arc neurones, and the majority of CART-containing neurones in the Arc also contain POMC mRNA. We investigated possible interactions between these neuropeptides in vitro using a rat hypothalamic explant system. Administration of 1, 10 and 100 nm of NPY to hypothalamic explants significantly increased release of Agrp(83-132)-immunoreactivity (IR). NPY (10 and 100 nm) significantly increased the release of CART(55-102)-IR and alpha-MSH-IR from hypothalamic explants. Agrp(83-132) (10 nm) administered to hypothalamic explants significantly increased the release of NPY-IR. Agrp(83-132) (10 and 100 nm) significantly decreased the release of CART(55-102)-IR from hypothalamic explants. Administration of 1, 10 and 100 nm CART(55-102) to hypothalamic explants resulted in a significant increase in NPY-IR release. Administration of 10 nm CART(55-102) to hypothalamic explants significantly increased the release of Agrp(83-132)-IR. NDP-MSH (10 nm) administered to hypothalamic explants significantly increased the release of NPY-IR. NDP-MSH (10 and 100 nm) significantly increased the release of Agrp(83-132)-IR from hypothalamic explants. These data suggest that orexigenic neuropeptides in the arcuate nucleus stimulate the release of each other, perhaps reinforcing orexigenic behaviour via a positive-feedback loop. Our results are also in keeping with the possibility that the melanocortin-3 receptor in the arcuate nucleus may influence the release of arcuate neuropeptides.

The pituitary-skin connection in amphibians. Reciprocal regulation of melanotrope cells and dermal melanocytes.

PubMed

Vaudry, H; Chartrel, N; Desrues, L; Galas, L; Kikuyama, S; Mor, A; Nicolas, P; Tonon, M C

1999-10-20

In amphibians, alpha-MSH secreted by the pars intermedia of the pituitary plays a pivotal role in the process of skin color adaptation. Reciprocally, the skin of amphibians contains a number of regulatory peptides, some of which have been found to regulate the activity of pituitary melanotrope cells. In particular, the skin of certain species of amphibians harbours considerable amounts of thyrotropin-releasing hormone, a highly potent stimulator of alpha-MSH release. Recently, we have isolated and sequenced from the skin of the frog Phyllomedusa bicolor--a novel peptide named skin peptide tyrosine tyrosine (SPYY), which exhibits 94% similarity with PYY from the frog Rana ridibunda. For concentrations ranging from 5 x 10(-10) to 10(-7) M, SPYY induces a dose-related inhibition of alpha-MSH secretion. At a dose of 10(-7) M, SPYY totally abolished alpha-MSH release. These data strongly suggest the existence of a regulatory loop between the pars intermedia of the pituitary and the skin in amphibians.

Changes in alpha-L-arabinofuranosidase activity in peel and pulp of banana (Musa sp.) fruits during ripening and softening.

PubMed

Zhuang, Jun-Ping; Su, Jing; Li, Xue-Ping; Chen, Wei-Xin

2007-04-01

Arabinose is one of the most dynamic cell wall glycosyl residues released during fruit ripening, alpha-L-arabinofuranosidase (alpha-Arab) are major glycosidases that may remove arabinose units from fruit cell wall polysaccharides. To find out whether alpha-Arab plays important roles in banana fruit softening, the enzyme activities in peel and pulp, fruit firmness, respiration rate and ethylene release rate were assayed during banana softening. The results showed that alpha-Arab activities in banana pulp and peel increased slightly at the beginning of storage and reached their maxima when the fruit firmness decreased drastically, alpha-Arab activity increased by more than ten folds in both pulp and peel during ripening and alpha-Arab activities were higher in pulp than in peel. Treatment of banana fruits with ethylene absorbent postponed the time of reaching of its maxima of respiration and ethylene, enhanced the firmness of pup and decreased alpha-Arab activity in the peel and pulp. These results suggest that alpha-Arab induced the decrease of fruit firmness and played an important role in banana fruit softening, and its activity was regulated by ethylene.

The alpha(2a)-adrenergic receptor plays a protective role in mouse behavioral models of depression and anxiety.

PubMed

Schramm, N L; McDonald, M P; Limbird, L E

2001-07-01

The noradrenergic system is involved in the regulation of many physiological and psychological processes, including the modulation of mood. The alpha(2)-adrenergic receptors (alpha(2)-ARs) modulate norepinephrine release, as well as the release of serotonin and other neurotransmitters, and are therefore potential targets for antidepressant and anxiolytic drug development. The current studies were undertaken to examine the role of the alpha(2A) subtype of alpha(2)-AR in mouse behavioral models of depression and anxiety. We have observed that the genetic knock-out of the alpha(2A)-AR makes mice less active in a modified version of Porsolt's forced swim test and insensitive to the antidepressant effects of the tricyclic drug imipramine in this paradigm. Furthermore, alpha(2A)-AR knock-out mice appear more anxious than wild-type C57 Bl/6 mice in the rearing and light-dark models of anxiety after injection stress. These findings suggest that the alpha(2A)-AR may play a protective role in some forms of depression and anxiety and that the antidepressant effects of imipramine may be mediated by the alpha(2A)-AR.

Measurements of Lyman-Alpha Escape From HST Far-UV Spectral SNAP Survey of 33 Starforming Galaxies: Initial Results

NASA Astrophysics Data System (ADS)

Redwine, Keith

2018-01-01

This thesis will describe and analyze far-UV spectra from nearby starforming galaxies to investigate how line features like the hydrogen Lyman-alpha (Lyα) line at 1216 Å are related to the local properties of the host galaxy. It has been suggested that Lyα can be used as a proxy for the escape of Lyman continuum (LyC) radiation, the escape of of which from bright regions of galaxies is of particular interest. Most notably, the reionization epoch of neutral atomic hydrogen in the universe over a redshift range from z∼6 to z∼12, was highly dependent on the flux of ionizing LyC photons in the interstellar and intergalactic media. Expanding our understanding of the dynamics of the Lyα escape fraction (fLyα) from the local environment of its emission could be key to determining a total LyC escape fraction (fLyC) across all morphologies of galaxies. The wide range of Lyα emitters and absorbors (occasionally both) of this Cycle 22 SNAP survey observed by the Cosmic Origins Spectrograph (COS) onboard Hubble Space Telescope (HST) provides a unique look at far-UV spectra in candidate LyC emitters. Lyα profiles are easily observable in short exposures, and line features discernable in the low-resolution G140L mode can inform and guide future observations by COS or other FUV spectroscopy.

The therapeutic potential of polymersomes loaded with 225Ac evaluated in 2D and 3D in vitro glioma models.

PubMed

de Kruijff, R M; van der Meer, A J G M; Windmeijer, C A A; Kouwenberg, J J M; Morgenstern, A; Bruchertseifer, F; Sminia, P; Denkova, A G

2018-06-01

Alpha emitters have great potential in targeted tumour therapy, especially in destroying micrometastases, due to their high linear energy transfer (LET). To prevent toxicity caused by recoiled daughter atoms in healthy tissue, alpha emitters like 225 Ac can be encapsulated in polymeric nanocarriers (polymersomes), which are capable of retaining the daughter atoms to a large degree. In the translation to a (pre-)clinical setting, it is essential to evaluate their therapeutic potential. As multicellular tumour spheroids mimic a tumour microenvironment more closely than a two-dimensional cellular monolayer, this study has focussed on the interaction of the polymersomes with U87 human glioma spheroids. We have found that polymersomes distribute themselves throughout the spheroid after 4 days which, considering the long half-life of 225 Ac (9.9 d) (Vaidyanathan and Zalutsky, 1996), allows for irradiation of the entire spheroid. A decrease in spheroidal growth has been observed upon the addition of only 0.1 kBq 225 Ac, an effect which was more pronounced for the 225 Ac in polymersomes than when only coupled to DTPA. At higher activities (5 kBq), the spheroids have been found to be destroyed completely after two days. We have thus demonstrated that 225 Ac containing polymersomes effectively inhibit tumour spheroid growth, making them very promising candidates for future in vivo testing. Copyright © 2018 Elsevier B.V. All rights reserved.

Evaluation of commercially supplied silver coated Teflon for spacecraft temperature control usage

NASA Technical Reports Server (NTRS)

Heaney, J. B.

1974-01-01

A series of tests are described which were performed to evaluate the acceptability of a commercially supplied silver backed teflon thermal control coating relative to teflon previously coated at GSFC. Optical measurements made on numerous samples indicate that the commercial material possesses an average solar absorptance of 0.085, an emittance of 0.76 and an average alpha/epsilon equal to 0.112, all of which are equivalent to the GSFC coated teflon. The emittance of the protective inconel backing was found to be 0.037. The coating is shown to have good adhesion at the Ag-teflon interface and exposure to UV irradiation uncovered no coating irregularities. Temperature cycling over the range -135 C to +200 C produced crazing in the evaporated Ag layer as expected but no delamination was observed. The suitability of Mystik no. 7366 and 3M no. 467 adhesives as bonding agents for the metallized polymer is demonstrated. Various problems associated with production reproducibility and selection of a proper bonding process are discussed.

Anthropogenic 129I in the atmosphere: overview over major sources, transport processes and deposition pattern.

PubMed

Reithmeier, H; Lazarev, V; Rühm, W; Nolte, E

2010-10-01

Wet and, to a lesser extent, dry deposition of atmospheric (129)I are known to represent the dominating processes responsible for (129)I in continental environmental samples that are remote from (129)I sources and not directly influenced by any liquid (129)I release of nuclear installations. Up to now, however, little is known about the major emitters and the related global deposition pattern of (129)I. In this work an overview over major sources of (129)I is given, and hitherto unknown time-dependent releases from these were estimated. Total gaseous (129)I releases from the US and former Soviet reprocessing facilities Hanford, Savannah River, Mayak, Seversk and Zheleznogorsk were found to have been 0.53, 0.27, 1.05, 0.23 and 0.14TBq, respectively. These facilities were thus identified as major airborne (129)I emitters. The global deposition pattern due to the (129)I released, depending on geographic latitude and longitude, and on time was studied using a box model describing the global atmospheric transport and deposition of (129)I. The model predictions are compared to (129)I concentrations measured by means of Accelerator Mass Spectrometry (AMS) in water samples that were collected from various lakes in Asia, Africa, America and New Zealand, and to published values. As a result, both pattern and temporal evolution of (129)I deposition values measured in and calculated for different types of environmental samples are, in general, in good agreement. This supports our estimate on atmospheric (129)I releases and the considered substantial transport and deposition mechanisms in our model calculations. Copyright 2010 Elsevier B.V. All rights reserved.

Hit rates and radiation doses to nuclei of bone lining cells from alpha-particle-emitting radionuclides

NASA Technical Reports Server (NTRS)

Polig, E.; Jee, W. S.; Kruglikov, I. L.

1992-01-01

Factors relating the local concentration of a bone-seeking alpha-particle emitter to the mean hit rate have been determined for nuclei of bone lining cells using a Monte Carlo procedure. Cell nuclei were approximated by oblate spheroids with dimensions and location taken from a previous histomorphometric study. The Monte Carlo simulation is applicable for planar and diffuse labels at plane or cylindrical bone surfaces. Additionally, the mean nuclear dose per hit, the dose mean per hit, the mean track segment length and its second moment, the percentage of stoppers, and the frequency distribution of the dose have been determined. Some basic features of the hit statistics for bone lining cells have been outlined, and the consequences of existing standards of radiation protection with regard to the hit frequency to cell nuclei are discussed.

Directional gamma detector

DOEpatents

LeVert, Francis E.; Cox, Samson A.

1981-01-01

An improved directional gamma radiation detector has a collector sandwiched etween two layers of insulation of varying thicknesses. The collector and insulation layers are contained within an evacuated casing, or emitter, which releases electrons upon exposure to gamma radiation. Delayed electrons and electrons entering the collector at oblique angles are attenuated as they pass through the insulation layers on route to the collector.

Alpha emitter radium-223 and survival in metastatic prostate cancer.

PubMed

Parker, C; Nilsson, S; Heinrich, D; Helle, S I; O'Sullivan, J M; Fosså, S D; Chodacki, A; Wiechno, P; Logue, J; Seke, M; Widmark, A; Johannessen, D C; Hoskin, P; Bottomley, D; James, N D; Solberg, A; Syndikus, I; Kliment, J; Wedel, S; Boehmer, S; Dall'Oglio, M; Franzén, L; Coleman, R; Vogelzang, N J; O'Bryan-Tear, C G; Staudacher, K; Garcia-Vargas, J; Shan, M; Bruland, Ø S; Sartor, O

2013-07-18

Radium-223 dichloride (radium-223), an alpha emitter, selectively targets bone metastases with alpha particles. We assessed the efficacy and safety of radium-223 as compared with placebo, in addition to the best standard of care, in men with castration-resistant prostate cancer and bone metastases. In our phase 3, randomized, double-blind, placebo-controlled study, we randomly assigned 921 patients who had received, were not eligible to receive, or declined docetaxel, in a 2:1 ratio, to receive six injections of radium-223 (at a dose of 50 kBq per kilogram of body weight intravenously) or matching placebo; one injection was administered every 4 weeks. In addition, all patients received the best standard of care. The primary end point was overall survival. The main secondary efficacy end points included time to the first symptomatic skeletal event and various biochemical end points. A prespecified interim analysis, conducted when 314 deaths had occurred, assessed the effect of radium-223 versus placebo on survival. An updated analysis, when 528 deaths had occurred, was performed before crossover from placebo to radium-223. At the interim analysis, which involved 809 patients, radium-223, as compared with placebo, significantly improved overall survival (median, 14.0 months vs. 11.2 months; hazard ratio, 0.70; 95% confidence interval [CI], 0.55 to 0.88; two-sided P=0.002). The updated analysis involving 921 patients confirmed the radium-223 survival benefit (median, 14.9 months vs. 11.3 months; hazard ratio, 0.70; 95% CI, 0.58 to 0.83; P<0.001). Assessments of all main secondary efficacy end points also showed a benefit of radium-233 as compared with placebo. Radium-223 was associated with low myelosuppression rates and fewer adverse events. In this study, which was terminated for efficacy at the prespecified interim analysis, radium-223 improved overall survival. (Funded by Algeta and Bayer HealthCare Pharmaceuticals; ALSYMPCA ClinicalTrials.gov number, NCT00699751.).

The BetaCage, an ultra-sensitive screener for surface contamination

NASA Astrophysics Data System (ADS)

Bunker, R.; Ahmed, Z.; Bowles, M. A.; Golwala, S. R.; Grant, D. R.; Kos, M.; Nelson, R. H.; Schnee, R. W.; Rider, A.; Wang, B.; Zahn, A.

2013-08-01

Material screening for identifying low-energy electron emitters and alpha-decaying isotopes is now a prerequisite for rare-event searches (e.g., dark-matter direct detection and neutrinoless double-beta decay) for which surface radiocon-tamination has become an increasingly important background. The BetaCage, a gaseous neon time-projection chamber, is a proposed ultra-sensitive (and nondestructive) screener for alpha-and beta-emitting surface contaminants to which existing screening facilities are insufficiently sensitive. Sensitivity goals are 0.1 betas keV-1 m-2 day-1 and 0.1 alphas m-2 day-1, with the former limited by Compton scattering of photons in the screening samples and (thanks to tracking) the latter expected to be signal-limited; radioassays and simulations indicate backgrounds from detector materials and radon daughters should be subdominant. We report on details of the background simulations and detector design that provide the discrimination, shielding, and radiopurity necessary to reach our sensitivity goals for a chamber with a 95 × 95 cm2 sample area positioned below a 40 cm drift region and monitored by crisscrossed anode and cathode planes consisting of 151 wires each.

X-ray and multiwavelength insights into the inner structure of high-luminosity disc-like emitters

NASA Astrophysics Data System (ADS)

Luo, B.; Brandt, W. N.; Eracleous, M.; Wu, Jian; Hall, P. B.; Rafiee, A.; Schneider, D. P.; Wu, Jianfeng

2013-02-01

We present X-ray and multiwavelength studies of a sample of eight high-luminosity active galactic nuclei (AGN) with disc-like Hβ emission-line profiles selected from the Sloan Digital Sky Survey Data Release 7. These sources have higher redshift (z ≈ 0.6) than the majority of the known disc-like emitters, and they occupy a largely unexplored space in the luminosity-redshift plane. Seven sources have typical AGN X-ray spectra with power-law photon indices of Γ ≈ 1.4-2.0; two of them show some X-ray absorption (column density NH ≈ 1021-1022 cm-2 for neutral gas). The other source, J0850+4451, has only three hard X-ray photons detected and is probably heavily obscured (NH ≳ 3 × 1023 cm-2). This object is also identified as a low-ionization broad absorption line (BAL) quasar based on Mg II λ2799 absorption; it is the first disc-like emitter reported that is also a BAL quasar. The infrared-to-ultraviolet (UV) spectral energy distributions (SEDs) of these eight sources are similar to the mean SEDs of typical quasars with a UV `bump', suggestive of standard accretion discs radiating with high efficiency, which differs from low-luminosity disc-like emitters. Studies of the X-ray-to-optical power-law slope parameters (αOX) indicate that there is no significant excess X-ray emission in these high-luminosity disc-like emitters. Energy budget analysis suggests that for disc-like emitters in general, the inner disc must illuminate and ionize the outer disc efficiently (≈15 per cent of the nuclear ionizing radiation is required on average) via direct illumination and/or scattering. Warped accretion discs are probably needed for direct illumination to work in high-luminosity objects, as their geometrically thin inner discs decrease the amount of direct illumination possible for a flat disc.

Inhibition of TNF-alpha-induced NF-kappaB activation and IL-8 release in A549 cells with the proteasome inhibitor MG-132.

PubMed

Fiedler, M A; Wernke-Dollries, K; Stark, J M

1998-08-01

The working hypothesis of the studies described herein was that inhibition of proteasome-mediated IkappaB degradation would inhibit TNF-alpha-induced nuclear factor-kappaB (NF-kappaB) activation, interleukin-8 (IL-8) gene transcription, and IL-8 protein release in A549 cells. Mutational analysis of the 5' flanking region of the IL-8 gene confirmed that an intact NF-kappaB site is necessary for TNF-alpha-induced IL-8 gene transcription. The addition of TNF-alpha to A549 cells resulted in rapid loss of IkappaB from the cytoplasm of cells, associated with a corresponding increase in NF-kappaB-binding activity in nuclear extracts from the cells. However, pretreatment of the cells with the proteasome inhibitor N-cbz-Leu-Leu-leucinal (MG-132, 10 microM) reversed the effects of TNF-alpha on IL-8 release from A549 cells (as determined with an enzyme-linked immunosorbent assay [ELISA]) and on IL-8 gene transcription (as determined with reporter-gene assays). MG-132 reversed the effects of TNF-alpha on IkappaB degradation as determined by Western blot analysis. IkappaB phosphorylation and ubiquination were not altered by MG-132, which implies that the effects of MG-132 were secondary to proteasome inhibition. MG-132 also reversed the increase in NF-kappaB binding in nuclear extracts from TNF-alpha-treated cells. These studies show that inhibition of proteasome-mediated IkappaB degradation results in inhibition of TNF-alpha induced IL-8 production in A549 cells by limiting NF-kappaB-mediated gene transcription.

Simulation study on beam loss in the alpha bucket regime during SIS-100 proton operation

NASA Astrophysics Data System (ADS)

Sorge, S.

2018-02-01

Crossing the transition energy γt in synchrotrons for high intensity proton beams requires well tuned jump schemes and is usually accompanied by longitudinal emittance growth. In order to avoid γt crossing during proton operation in the projected SIS-100 synchrotron special high-γt lattice settings have been developed, in order to keep γt above the beam extraction energy. A further advantage of this scheme is the formation of alpha buckets which naturally lead to short proton bunches, required for the foreseen production and storage of antiprotons for the FAIR facility. Special attention is turned on the imperfections of the superconducting SIS-100 magnets because together with the high-γt lattice settings, they could potentially lead to enhanced beam loss. The aim of the present work is to estimate the beam loss by means of particle tracking simulations.

Tailoring Thin Film-Lacquer Coatings for Space Applications

NASA Technical Reports Server (NTRS)

Peters, Wanda C.; Harris, George; Miller, Grace; Petro, John

1998-01-01

Thin film coatings have the capability of obtaining a wide range of thermal radiative properties, but the development of thin film coatings can sometimes be difficult and costly when trying to achieve highly specular surfaces. Given any space mission's then-nal control requirements, there is often a need for a variation of solar absorptance (alpha(sub s)), emittance (epsilon) and/or highly specular surfaces. The utilization of thin film coatings is one process of choice for meeting challenging thermal control requirements because of its ability to provide a wide variety of alpha(sub s)/epsilon ratios. Thin film coatings' radiative properties can be tailored to meet specific thermal control requirements through the use of different metals and the variation of dielectric layer thickness. Surface coatings can be spectrally selective to enhance radiative coupling and decoupling. The application of lacquer to a surface can also provide suitable specularity for thin film application without the cost and difficulty associated with polishing.

Spectral Energy Distribution Fitting of Hetdex Pilot Survey Ly-alpha Emitters in Cosmos and Goods-N

NASA Technical Reports Server (NTRS)

Hagen, Alex; Ciardullo, Robin; Cronwall, Caryl; Acquaviva, Viviana; Bridge, Joanna; Zeimann, Gregory R.; Blanc, Guillermo; Bond, Nicholas; Finkelstein, Steven L.; Song, Mimi;

From Beamline to Scanner with 225Ac

NASA Astrophysics Data System (ADS)

Robertson, Andrew K. H.; Ramogida, Caterina F.; Kunz, Peter; Rodriguez-Rodriguez, Cristina; Schaffer, Paul; Sossi, Vesna

2016-09-01

Due to the high linear energy transfer and short range of alpha-radiation, targeted radiation therapy using alpha-emitting pharmaceuticals that successfully target small disease clusters will kill target cells with limited harm to healthy tissue, potentially treating the most aggressive forms of cancer. As the parent of a decay chain with four alpha- and two beta-decays, 225Ac is a promising candidate for such a treatment. However, this requires retention of the entire decay chain at the target site, preventing the creation of freely circulating alpha-emitters that reduce therapeutic effect and increase toxicity to non-target tissues. Two major challenges to 225Ac pharmaceutical development exist: insufficient global supply, and the difficulty of preventing toxicity by retaining the entire decay chain at the target site. While TRIUMF works towards large-scale (C i amounts) production of 225Ac, we already use our Isotope Separation On-Line facility to provide small (< 1 mCi) quantities for in-house chemistry and imaging research that aims to improve and assess 225Ac radiopharmaceutical targeting. This presentation provides an overview of this research program and the journey of 225Ac from the beamline to the scanner. This research is funded by the Natural Sciences and Engineering Research Council of Canada.

Utilization of alpha-ketoglutarate as a precursor for transmitter glutamate in cultured cerebellar granule cells.

PubMed

Peng, L A; Schousboe, A; Hertz, L

1991-01-01

Alpha-ketoglutarate together with an amino group donor (alanine) was shown to be able to serve as a precursor for the glutamate pool which is released by potassium-induced depolarization (i.e., transmitter glutamate) in cerebellar granule cells. However, these compounds could not be utilized as precursors for intracellular glutamate or for release of transmitter aspartate. The formation of transmitter glutamate was inhibited by the transamination inhibitor aminooxyacetic acid but not by phenylsuccinate, an inhibitor of the dicarboxylate carrier in the mitochondrial membrane. Both of these inhibitors have previously been found to inhibit synthesis of transmitter glutamate from glutamine. The results support the hypothesis that alpha-ketoglutarate and alanine undergo transmination in the cytosol to form pyruvate and glutamate, and that this glutamate pool is available for transmitter release of glutamate but does not constitute the major intracellular pool of glutamate.

The mean ultraviolet spectrum of a representative sample of faint z ˜ 3 Lyman alpha emitters

NASA Astrophysics Data System (ADS)

Nakajima, Kimihiko; Fletcher, Thomas; Ellis, Richard S.; Robertson, Brant E.; Iwata, Ikuru

2018-06-01

We discuss the rest-frame ultraviolet (UV) emission line spectra of a large (˜100) sample of low luminosity redshift z ˜ 3.1 Lyman alpha emitters (LAEs) drawn from a Subaru imaging survey in the SSA22 survey field. Our earlier work based on smaller samples indicated that such sources have high [O III]/[O II] line ratios possibly arising from a hard ionizing spectrum that may be typical of similar sources in the reionization era. With optical spectra secured from VLT/VIMOS, we re-examine the nature of the ionizing radiation in a larger sample using the strength of the high ionization diagnostic emission lines of CIII]λ1909, CIVλ1549, HEIIλ1640, and O III]λλ1661, 1666 Å in various stacked subsets. Our analysis confirms earlier suggestions of a correlation between the strength of Ly α and CIII] emission and we find similar trends with broad-band UV luminosity and rest-frame UV colour. Using various diagnostic line ratios and our stellar photoionization models, we determine both the gas phase metallicity and hardness of the ionization spectrum characterized by ξion - the number of Lyman continuum photons per UV luminosity. We confirm our earlier suggestion that ξion is significantly larger for LAEs than for continuum-selected Lyman break galaxies, particularly for those LAEs with the faintest UV luminosities. We briefly discuss the implications for cosmic reionization if the metal-poor intensely star-forming systems studied here are representative examples of those at much higher redshift.

Boron modulates extracellular matrix and TNF alpha synthesis in human fibroblasts.

PubMed

Benderdour, M; Hess, K; Dzondo-Gadet, M; Nabet, P; Belleville, F; Dousset, B

1998-05-29

Boric acid was not mitogenic for human fibroblasts and it did not change cell viability until 0.5% (w/v). Boric acid treatment affected the metabolism of human dermal fibroblasts in culture, decreasing the synthesis of extracellular matrix macromolecules such as proteoglycans, collagen, and total proteins. It also increased the release of these molecules into the culture medium. The principal proteins secreted into the medium after boric acid treatment had molecular masses of 90, 70, 58, 49, and 43 kDa and faint bands were detected by electrophoresis between 14 and 30 kDa. hsp 70 and TNF alpha were detected among the secreted proteins by immunoblotting, and the amount of TNF alpha released was quantified by radioimmunoassay. Total mRNA levels were higher after boric acid treatment and peaked after 6 h of treatment. TNF alpha mRNA was undetectable in unstimulated fibroblasts and two TNF alpha mRNA bands were detected after stimulation: immature mRNA (4.8 kb) and mature TNF alpha mRNA (1.9 kb). Thus, the effects of boric acid observed in wound repair in vivo may be due to TNF alpha synthesis and secretion.

Modulation of starch digestion for slow glucose release through "toggling" of activities of mucosal "alpha"-glucosidases

USDA-ARS?s Scientific Manuscript database

Starch digestion involves the breakdown by alpha-amylase to small linear and branched malto-oligosaccharides, which are in turn hydrolyzed to glucose by the mucosal alpha-glucosidases, maltase-glucoamylase (MGAM) and sucrase-isomaltase (SI). MGAM and SI are anchored to the small intestinal brush-bor...

Tocotrienols suppress proinflammatory markers and cyclooxygenase-2 expression in RAW264.7 macrophages.

PubMed

Yam, Mun-Li; Abdul Hafid, Sitti Rahma; Cheng, Hwee-Ming; Nesaretnam, Kalanithi

2009-09-01

Tocotrienols are powerful chain breaking antioxidant. Moreover, they are now known to exhibit various non-antioxidant properties such as anti-cancer, neuroprotective and hypocholesterolemic functions. This study was undertaken to investigate the anti-inflammatory effects of tocotrienol-rich fraction (TRF) and individual tocotrienol isoforms namely delta-, gamma-, and alpha-tocotrienol on lipopolysaccharide-stimulated RAW264.7 macrophages. The widely studied vitamin E form, alpha-tocopherol, was used as comparison. Stimulation of RAW264.7 with lipopolysaccharide induced the release of various inflammatory markers. 10 mcirog/ml of TRF and all tocotrienol isoforms significantly inhibited the production of interleukin-6 and nitric oxide. However, only alpha-tocotrienol demonstrated a significant effect in lowering tumor necrosis factor-alpha production. Besides, TRF and all tocotrienol isoforms except gamma-tocotrienol reduced prostaglandin E(2) release. It was accompanied by the down-regulation of cyclooxygenase-2 gene expression by all vitamin E forms except alpha-tocopherol. Collectively, the data suggested that tocotrienols are better anti-inflammatory agents than alpha-tocopherol and the most effective form is delta-tocotrienol.

Radiological Assessment for the Removal of Legacy BPA Power Lines that Cross the Hanford Site

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

Millsap, William J.; Brush, Daniel J.

This paper discusses some radiological field monitoring and assessment methods used to assess the components of an old electrical power transmission line that ran across the Hanford Site between the production reactors area (100 Area) and the chemical processing area (200 Area). This task was complicated by the presence of radon daughters -- both beta and alpha emitters -- residing on the surfaces, particularly on the surfaces of weathered metals and metals that had been electrically-charged. In many cases, these activities were high compared to the DOE Surface Contamination Guidelines, which were used as guides for the assessment. These methodsmore » included the use of the Toulmin model of argument, represented using Toulmin diagrams, to represent the combined force of several strands of evidences, rather than a single measurement of activity, to demonstrate beyond a reasonable doubt that no or very little Hanford activity was present and mixed with the natural activity. A number of forms of evidence were used: the overall chance of Hanford contamination; measurements of removable activity, beta and alpha; 1-minute scaler counts of total surface activity, beta and alpha, using "background makers"; the beta activity to alpha activity ratios; measured contamination on nearby components; NaI gamma spectral measurements to compare uncontaminated and potentially-contaminated spectra, as well as measurements for the sentinel radionuclides, Am- 241 and Cs-137 on conducting wire; comparative statistical analyses; and in-situ measurements of alpha spectra on conducting wire showing that the alpha activity was natural Po-210, as well as to compare uncontaminated and potentially-contaminated spectra.« less

Arachidonic acid and prostaglandin endoperoxide metabolism in isolated rabbit and coronary microvessels and isolated and cultivated coronary microvessel endothelial cells.

PubMed Central

Gerritsen, M E; Cheli, C D

1983-01-01

Isolated microvessels and isolated and cultured microvessel endothelial cells were prepared from rabbit cardiac muscle. Pathways of arachidonic acid metabolism were determined by measurement of exogenous substrate utilization [( 1-14C]arachidonic acid incorporation and release from intact tissue and cells; [1-14C]prostaglandin H2 (PGH2) metabolism by broken cell preparations) and by quantification of endogenous products (immunoreactive 6-keto-prostaglandin F1 alpha (PGF1 alpha) and prostaglandin E (PGE) release) by selective radioimmunoassay. Rabbit coronary microvessels and derived microvascular endothelial cells (RCME cells) synthesized two major products of the cyclooxygenase pathway: 6-keto-PGF1 alpha (hydrolytic product of prostaglandin I2) and PGE2. A reduced glutathione requiring PGH-E isomerase was demonstrated in coronary microvessels and RCME cells, but not in rabbit circumflex coronary artery or aorta. In addition, a minor amount of a compound exhibiting similar characteristics to 6-keto-PGE1 was found to be produced by microvessels and RCME cells. Measurement of endogenously released prostaglandins indicated that under basal and stimulated conditions, PGE release exceeded that of 6-keto-PGF1 alpha. Microvessels and microvessel endothelial cells derived from cardiac muscle of rabbit exhibit pathways of arachidonate metabolism that are different from those of many large blood vessels and derived endothelial cells. Images PMID:6415116

The effect of supplemental energy, nitrogen, and protein on feed intake, digestibility, and nitrogen flux across the gut and liver in sheep fed low-quality forage.

PubMed

Ferrell, C L; Kreikemeier, K K; Freetly, H C

1999-12-01

Our objective was to determine the impact of supplemental energy, N, and protein on feed intake and N metabolism in sheep fed low-quality forage. Six Texel x Dorset wethers (16 mo, 63+/-3.1 kg) fitted with mesenteric, portal, and hepatic venous catheters were used in a Latin square design with five sampling periods. Lambs were fed chopped bromegrass hay (4.3% CP) to appetite, and a mineral mixture was given. Treatments were 1) control (no supplement), 2) energy (cornstarch, molasses, and soybean oil), 3) energy plus urea, 4) energy plus soybean meal (SBM), and 5) energy plus ruminally undegraded protein (RUP; 50:50 mixture of blood and feather meals). Supplements were fed once daily (.3% BW). Forage DMI did not differ (P = .13), but intake of total DM, N, and energy differed (P<.01) among treatments. Apparent digestibilities of DM, OM, and energy were less (P<.01) for control than for other treatments. Apparent N digestibility was least for control and energy and greatest for urea treatments (P<.05). As a result, digested DM, OM, and energy ranked from least to greatest were control, energy, urea, SBM, and RUP, respectively. Apparently digested N was 2.44, 2.24, 11.39, 9.80, and 11.25 g/d for control, energy, urea, SBM, and RUP (P<.01; SE = .10). Hour of sampling x treatment was a significant source of variation for blood concentrations of ammonia N and urea N, net ammonia N release from portal-drained viscera (PDV) and liver, and urea N release from splanchnic tissues. These results were primarily because patterns through time for the urea treatment differed from the other treatments. Net PDV release of alpha-amino N did not differ (P>.05) between control and energy treatments. Values for those treatments were about one-half of values for urea, SBM, and RUP treatments, which did not differ (P>.05). Hepatic net uptake (negative release) of alpha-amino N for control was 53% of values for the other treatments, which did not differ (P>.05). Net release of alpha-amino N from splanchnic tissues did not differ among treatments (P = .34) and did not differ from zero. The data indicate that arterial alpha-amino N concentration, hepatic alpha-amino N uptake, PDV release and hepatic uptake of ammonia N, and hepatic release of urea N were greater in energy than in control treatments. We also found that hepatic uptake of alpha-amino N was 187% of PDV release in energy-supplemented lambs. These results suggest that energy supplementation of a protein-limiting diet stimulated mobilization of body protein.

A High Space Density of Luminous Lyman Alpha Emitters at z ∼ 6.5

NASA Astrophysics Data System (ADS)

Bagley, Micaela B.; Scarlata, Claudia; Henry, Alaina; Rafelski, Marc; Malkan, Matthew; Teplitz, Harry; Dai, Y. Sophia; Baronchelli, Ivano; Colbert, James; Rutkowski, Michael; Mehta, Vihang; Dressler, Alan; McCarthy, Patrick; Bunker, Andrew; Atek, Hakim; Garel, Thibault; Martin, Crystal L.; Hathi, Nimish; Siana, Brian

2017-03-01

We present the results of a systematic search for Lyα emitters (LAEs) at 6≲ z≲ 7.6 using the HST WFC3 Infrared Spectroscopic Parallel (WISP) Survey. Our total volume over this redshift range is ∼ 8× {10}5 Mpc3, comparable to many of the narrowband surveys despite their larger area coverage. We find two LAEs at z = 6.38 and 6.44 with line luminosities of {L}Lyα }∼ 4.7× {10}43 erg s‑1, putting them among the brightest LAEs discovered at these redshifts. Taking advantage of the broad spectral coverage of WISP, we are able to rule out almost all lower-redshift contaminants. The WISP LAEs have a high number density of 7.7× {10}-6 Mpc‑3. We argue that the LAEs reside in megaparsec-scale ionized bubbles that allow the Lyα photons to redshift out of resonance before encountering the neutral intergalactic medium. We discuss possible ionizing sources and conclude that the observed LAEs alone are not sufficient to ionize the bubbles.

Fatty Acid Amide Hydrolase (FAAH) Inhibition Enhances Memory Acquisition through Activation of PPAR-alpha Nuclear Receptors

ERIC Educational Resources Information Center

Mazzola, Carmen; Medalie, Julie; Scherma, Maria; Panlilio, Leigh V.; Solinas, Marcello; Tanda, Gianluigi; Drago, Filippo; Cadet, Jean Lud; Goldberg, Steven R.; Yasar, Sevil

2009-01-01

Inhibitors of fatty acid amide hydrolase (FAAH) increase endogenous levels of anandamide (a cannabinoid CB[subscript 1]-receptor ligand) and oleoylethanolamide and palmitoylethanolamide (OEA and PEA, ligands for alpha-type peroxisome proliferator-activated nuclear receptors, PPAR-alpha) when and where they are naturally released in the brain.…

Feasibility of observing the α decay chains from isotopes of SHN with Z = 128, Z = 126, Z = 124 and Z = 122

NASA Astrophysics Data System (ADS)

Santhosh, K. P.; Priyanka, B.; Nithya, C.

2016-11-01

Within the Coulomb and proximity potential model for deformed nuclei (CPPMDN), the alpha decay properties of 34 isotopes of the superheavy nuclei with Z = 128 within the range 306 ≤ A ≤ 339 have been studied, considering both the parent and daughter nuclei to be deformed. The manuscript also deals with the decay properties of the isotopes of Z = 126 (within 288 ≤ A ≤ 339), Z = 124 (within 284 ≤ A ≤ 339) and Z = 122 (within 280 ≤ A ≤ 339). The alpha decay half lives thus evaluated have been compared with the values evaluated using other theoretical models and it was seen that, our theoretical alpha decay half lives match well with these values. Through the present study, we have underlined and have established the fact that, among the 192 isotopes considered in the present study, only those isotopes 321-324,328-335128, 318-320,323-327126, 305-308,315-322124 and 298-307,311-314122 can be synthesised and detected through alpha decay in laboratory. As the alpha decay half lives of these superheavy isotopes lie within the experimental limits, we hope these predictions, on the decay modes of these unknown nuclei, to pave the way for the future experiments. The proton separation energy calculations on 306-339128, 288-336126, 284-339124 and 280-339122 superheavy nuclei have also been done and the study revealed the probable proton emitters among these nuclei.

Plutonium and uranium determination in environmental samples: combined solvent extraction-liquid scintillation method.

PubMed

McDowell, W J; Farrar, D T; Billings, M R

1974-12-01

A method for the determination of uranium and plutonium by a combined high-resolution liquid scintillation-solvent extraction method is presented. Assuming a sample count equal to background count to be the detection limit, the lower detection limit for these and other alpha-emitting nuclides is 1.0 dpm with a Pyrex sample tube, 0.3 dpm with a quartz sample tube using present detector shielding or 0.02 d.p.m. with pulse-shape discrimination. Alpha-counting efficiency is 100%. With the counting data presented as an alpha-energy spectrum, an energy resolution of 0.2-0.3 MeV peak half-width and an energy identification to +/-0.1 MeV are possible. Thus, within these limits, identification and quantitative determination of a specific alpha-emitter, independent of chemical separation, are possible. The separation procedure allows greater than 98% recovery of uranium and plutonium from solution containing large amounts of iron and other interfering substances. In most cases uranium, even when present in 10(8)-fold molar ratio, may be quantitatively separated from plutonium without loss of the plutonium. Potential applications of this general analytical concept to other alpha-counting problems are noted. Special problems associated with the determination of plutonium in soil and water samples are discussed. Results of tests to determine the pulse-height and energy-resolution characteristics of several scintillators are presented. Construction of the high-resolution liquid scintillation detector is described.

Tocotrienol inhibits proliferation of human Tenon's fibroblasts in vitro: a comparative study with vitamin E forms and mitomycin C.

PubMed

Meyenberg, Alexander; Goldblum, David; Zingg, Jean-Marc; Azzi, Angelo; Nesaretnam, Kalanithi; Kilchenmann, Monika; Frueh, Beatrice E

2005-12-01

To evaluate the potential of the vitamin E compound alpha-tocotrienol as antifibrotic agent in vitro. Using human Tenon's capsule fibroblast cultures, the antiproliferative and cytotoxic effects of the different vitamin E forms alpha-tocopherol, alpha-tocopheryl acetate, alpha-tocopheryl succinate and alpha-tocotrienol were compared with those of mitomycin C. To mimic subconjunctival and regular oral application in vivo, exposure time of serum-stimulated and serum-restimulated fibroblasts (SF and RF, respectively) to vitamin E forms was set at 6 days. Cultures were only exposed for 5 min to mitomycin C due to its known acute toxicity and to mimic the short-time intraoperative administration. Proliferation (expressed as % of control) was determined by DNA content quantification on days 2, 4 and 6, whereas cytotoxicity was assessed by cell morphology and glucose 6-phosphate dehydrogenase (G6PD) release after 24 h. alpha-Tocopherol and alpha-tocopheryl acetate stimulated growth of SF, but not RF. Reduction of fibroblast content by alpha-tocopheryl succinate was accompanied by increased G6PD release and necrosis. Contrary to alpha-tocopheryl succinate, 50 microM or repeatedly 20 microM of alpha-tocotrienol significantly inhibited proliferation without causing cellular toxicity (maximal effect: 46.8%). RF were more sensitive to this effect than SF. Mitomycin C 100-400 microg/ml showed a stronger antiproliferative effect than alpha-tocotrienol (maximal effect: 13.8%). Morphologic characteristics of apoptosis were more commonly found under treatment with mitomycin C. Of the vitamin E forms tested, only alpha-tocotrienol significantly inhibited growth at non-toxic concentrations. In this in vitro study, antiproliferative effects of mitomycin C were stronger than those of alpha-tocotrienol.

Controls on the methane released through ebullition affected by permafrost degradation

Treesearch

S.J. Klapstein; M.R. Turetsky; A.D. McGuire; J.W. Harden; C.I. Czimczik; X. Xu; J.P. Chanton; J.M. Waddington

2014-01-01

Permafrost thaw in peat plateaus leads to the flooding of surface soils and the formation of collapse scar bogs, which have the potential to be large emitters of methane (CH4) from surface peat as well as deeper, previously frozen, permafrost carbon (C). We used a network of bubble traps, permanently installed 20 cm and 60 cm beneath the moss surface, to examine...

Role of astrocytes in reproduction and neuroprotection.

PubMed

Mahesh, Virendra B; Dhandapani, Krishnan M; Brann, Darrell W

2006-02-26

Hypothalamic astrocytes secrete TGF-beta and 3 alpha,5 alpha-tetrahydro progesterone (3 alpha,5 alpha-THP) in culture. When the astrocyte-conditioned medium (ACM) was incubated with the hypothalamic cell line GT1-7, it resulted in the secretion of GnRH. Immunoneutralization with TGF-beta antibody or ultra-filteration with a 10 kDa cut off filter resulted in attenuation of the GnRH releasing ability of ACM, indicating that TGF-beta was a major factor involved with GnRH release. Treatment with estrogens increases TGF-beta secretion. These observations indicate a significant role of astrocytes in GnRH secretion. Serum-deprivation results in the death of GT1-7 neurons in culture and addition of ACM or TGF-beta to the culture, attenuates cell death. The mechanism of protection from cell death appears to involve phosphorylation of MKK4, JNK, c-Jun(Ser63), and enhancement of AP-1 binding. Co-administration of JNK inhibitors, but not MEK inhibitors attenuated ACM or TGF-beta-induced c-Jun(Ser63) phosphorylation and their neuroprotective effects. These studies suggest that astrocytes can protect neurons, at least in part, by the release of TGF-beta and activation of a c-Jun/AP-1 protective pathway.

A Radium-223 Microgenerator from Cyclotron-Produced Trace Actinium-227

PubMed Central

Abou, Diane S.; Pickett, Juile; Mattson, John E.; Thorek, Daniel L. J.

2016-01-01

The alpha particle emitter Radium-223 dichloride (223RaCl2) has recently been approved for treatment of late-stage bone metastatic prostate cancer. There is considerable interest in studying this new agent outside of the clinical setting, however the supply of 223Ra is limited and expensive. We have engineered a 223Ra microgenerator using traces of 227Ac previously generated from cyclotron-produced 225Ac. Radiochemically pure 223RaCl2 was made, characterized, evaluated in vivo, and the source was recovered in high yield for regeneration of the microgenerator. PMID:27835737

Pertussis toxin-sensitive G-protein mediates the alpha 2-adrenergic receptor inhibition of melatonin release in photoreceptive chick pineal cell cultures

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

Pratt, B.L.; Takahashi, J.S.

The avian pineal gland is a photoreceptive organ that has been shown to contain postjunctional alpha 2-adrenoceptors that inhibit melatonin synthesis and/or release upon receptor activation. Physiological response and (32P)ADP ribosylation experiments were performed to investigate whether pertussis toxin-sensitive guanine nucleotide-binding proteins (G-proteins) were involved in the transduction of the alpha 2-adrenergic signal. For physiological response studies, the effects of pertussis toxin on melatonin release in dissociated cell cultures exposed to norepinephrine were assessed. Pertussis toxin blocked alpha 2-adrenergic receptor-mediated inhibition in a dose-dependent manner. Pertussis toxin-induced blockade appeared to be noncompetitive. One and 10 ng/ml doses of pertussis toxinmore » partially blocked and a 100 ng/ml dose completely blocked norepinephrine-induced inhibition. Pertussis toxin-catalyzed (32P)ADP ribosylation of G-proteins in chick pineal cell membranes was assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography. Membranes were prepared from cells that had been pretreated with 0, 1, 10, or 100 ng/ml pertussis toxin. In the absence of pertussis toxin pretreatment, two major proteins of 40K and 41K mol wt (Mr) were labeled by (32P)NAD. Pertussis toxin pretreatment of pineal cells abolished (32P) radiolabeling of the 40K Mr G-protein in a dose-dependent manner. The norepinephrine-induced inhibition of both cAMP efflux and melatonin release, as assessed by RIA of medium samples collected before membrane preparation, was also blocked in a dose-dependent manner by pertussis toxin. Collectively, these results suggest that a pertussis toxin-sensitive 40K Mr G-protein labeled by (32P)NAD may be functionally associated with alpha 2-adrenergic signal transduction in chick pineal cells.« less

Ero1alpha requires oxidizing and normoxic conditions to localize to the mitochondria-associated membrane (MAM).

PubMed

Gilady, Susanna Y; Bui, Michael; Lynes, Emily M; Benson, Matthew D; Watts, Russell; Vance, Jean E; Simmen, Thomas

2010-09-01

Protein secretion from the endoplasmic reticulum (ER) requires the enzymatic activity of chaperones and oxidoreductases that fold polypeptides and form disulfide bonds within newly synthesized proteins. The best-characterized ER redox relay depends on the transfer of oxidizing equivalents from molecular oxygen through ER oxidoreductin 1 (Ero1) and protein disulfide isomerase to nascent polypeptides. The formation of disulfide bonds is, however, not the sole function of ER oxidoreductases, which are also important regulators of ER calcium homeostasis. Given the role of human Ero1alpha in the regulation of the calcium release by inositol 1,4,5-trisphosphate receptors during the onset of apoptosis, we hypothesized that Ero1alpha may have a redox-sensitive localization to specific domains of the ER. Our results show that within the ER, Ero1alpha is almost exclusively found on the mitochondria-associated membrane (MAM). The localization of Ero1alpha on the MAM is dependent on oxidizing conditions within the ER. Chemical reduction of the ER environment, but not ER stress in general leads to release of Ero1alpha from the MAM. In addition, the correct localization of Ero1alpha to the MAM also requires normoxic conditions, but not ongoing oxidative phosphorylation.

Mitogenic action of tumour necrosis factor-alpha and interleukin-8 on explants of human duodenal mucosa.

PubMed

Zachrisson, K; Neopikhanov, V; Wretlind, B; Uribe, A

2001-08-07

Our aim is to examine whether tumour necrosis factor-alpha (TNF-alpha) and interleukin affect the mitotic activity in explants of human duodenal mucosa and to estimate the release of cytokines from explants incubated with TNF-alpha. Biopsy specimens of normal duodenal mucosa were taken from 19 subjects that underwent upper endoscopy for investigation of dyspeptic symptoms or chronic gastrointestinal bleeding. The specimens were processed following guidelines for organ culture technique. Paired biopsy specimens from 12 subjects were cultured for 23 h to achieve steady state and thereafter the explants were incubated 25 h with 10(-13)-10(-9) M of TNF-alpha or IL-8. Mitoses were arrested in the metaphase by adding vincristine sulphate for the last three hours. The explants were then fixed and processed for microdissection. Fifteen crypts were microdissected and the total number of metaphases was determined using the whole crypt as reference volume. The number of metaphases per crypt was also estimated in explants incubated with 10(-10) M TNF-alpha in the presence of anti-IL-8 antibodies. Additional duodenal explants from seven subjects were incubated with 10(-10) M TNF-alpha for 25 h. Thereafter the release of IL-1-beta, IL-6, IL-8 and interferon gamma (IFN-gamma) into the culture medium was measured by enzyme immunoassay and expressed as pg/mg protein. TNF-alpha and IL-8 significantly increased the number of metaphases/crypts (P<0.0001). The addition of anti-IL-8 slightly reduced the number of metaphases/crypt compared to the values observed in the explants incubated with 10(-10) M TNF-alpha alone (P<0.0001). The number of metaphases/crypt in the explants incubated with 10(-10) M TNF-alpha in the presence of anti-IL-8 antibodies was, however, markedly and significantly higher than that of the controls (P<0.000). TNF-alpha induced the release of IL-8 (P<0.01) and IL-6 (P<0.05) from the duodenal explants. TNF-alpha and IL-8 are potent mitogens to human small intestinal crypts. The mitogenic action of TNF-alpha is primarily a direct effect of the cytokine and only to a minor extent mediated by a secondary production of IL-8 in the duodenal explant. Our findings indicate that TNF-alpha and IL-8 may participate in the regulation of cell proliferation in the human small intestinal epithelium. Copyright 2001 Academic Press.

TNF-{alpha} upregulates the A{sub 2B} adenosine receptor gene: The role of NAD(P)H oxidase 4

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

St Hilaire, Cynthia; Koupenova, Milka; Carroll, Shannon H.

2008-10-24

Proliferation of vascular smooth muscle cells (VSMC), oxidative stress, and elevated inflammatory cytokines are some of the components that contribute to plaque formation in the vasculature. The cytokine tumor necrosis factor-alpha (TNF-{alpha}) is released during vascular injury, and contributes to lesion formation also by affecting VSMC proliferation. Recently, an A{sub 2B} adenosine receptor (A{sub 2B}AR) knockout mouse illustrated that this receptor is a tissue protector, in that it inhibits VSMC proliferation and attenuates the inflammatory response following injury, including the release of TNF-{alpha}. Here, we show a regulatory loop by which TNF-{alpha} upregulates the A{sub 2B}AR in VSMC in vitromore » and in vivo. The effect of this cytokine is mimicked by its known downstream target, NAD(P)H oxidase 4 (Nox4). Nox4 upregulates the A{sub 2B}AR, and Nox inhibitors dampen the effect of TNF-{alpha}. Hence, our study is the first to show that signaling associated with Nox4 is also able to upregulate the tissue protecting A{sub 2B}AR.« less

The BetaCage, an ultra-sensitive screener for surface contamination

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

Bunker, R.; Bowles, M. A.; Schnee, R. W.

Material screening for identifying low-energy electron emitters and alpha-decaying isotopes is now a prerequisite for rare-event searches (e.g., dark-matter direct detection and neutrinoless double-beta decay) for which surface radiocon-tamination has become an increasingly important background. The BetaCage, a gaseous neon time-projection chamber, is a proposed ultra-sensitive (and nondestructive) screener for alpha-and beta-emitting surface contaminants to which existing screening facilities are insufficiently sensitive. Sensitivity goals are 0.1 betas keV{sup −1} m{sup −2} day{sup −1} and 0.1 alphas m{sup −2} day{sup −1}, with the former limited by Compton scattering of photons in the screening samples and (thanks to tracking) the latter expectedmore » to be signal-limited; radioassays and simulations indicate backgrounds from detector materials and radon daughters should be subdominant. We report on details of the background simulations and detector design that provide the discrimination, shielding, and radiopurity necessary to reach our sensitivity goals for a chamber with a 95 × 95 cm{sup 2} sample area positioned below a 40 cm drift region and monitored by crisscrossed anode and cathode planes consisting of 151 wires each.« less

Initial Results of a Far-Ultraviolet Spectroscopic Survey of Nearby Star-forming Galaxies with the Cosmic Origins Spectrograph

NASA Astrophysics Data System (ADS)

Redwine, Keith; McCandliss, Stephan R.; Wofford, Aida; Leitherer, Claus; Heckman, Timothy M.; France, Kevin; Fleming, Brian

2017-01-01

We present initial results for the HST Cycle 22 proposal 13761. We proposed to observe 75 target star-forming galaxies at a redshift 0.02 < z < 0.24 in the G140L mode of COS, spanning a bandpass of 1100 < λ < 2400 angstroms, and have thus far observed 34 of them. The main thrust of this project is to provide a previously unavailable survey of star-forming galaxies in this redshift range, allowing investigation into the factors that determine the Lyman-alpha emission at these low redshifts. We have begun a statistical analysis of the relationship between Lyman-alpha emission and the morphologies of the galaxies, such as absorption line strengths of other species, including various ionization states of oxygen, silicon, and other species to probe intrinsic properties of the emitting galaxy, such as metallicity, the gas-to-dust ratio, and local velocity fields. We have acquired a very rich dataset, with enough samples to try to answer a variety of open questions regarding the far-ultraviolet spectra of bright Lyman-alpha emitters. This work is supported by a NASA Grant HST-GO-13761 to the Johns Hopkins University.

Nanostructured Solar Irradiation Control Materials for Solar Energy Conversion

NASA Technical Reports Server (NTRS)

Kang, Jinho; Marshall, I. A.; Torrico, M. N.; Taylor, C. R.; Ely, Jeffry; Henderson, Angel Z.; Kim, J.-W.; Sauti, G.; Gibbons, L. J.; Park, C.;

Roles of the bacterial cell wall and capsule in induction of tumor necrosis factor alpha by type III group B streptococci.

PubMed Central

Vallejo, J G; Baker, C J; Edwards, M S

1996-01-01

Group B streptococci (GBS) are the major cause of sepsis and fatal shock in neonates in the United States. The precise role of tumor necrosis factor alpha (TNF-alpha) in the development of human GBS sepsis has not been defined; however, whole GBS have been shown to induce the production of this inflammatory cytokine. We sought to determine which bacterial cell wall components of GBS are responsible for triggering TNF-alpha production. Human cord blood monocytes were stimulated with encapsulated (COH1) or unencapsulated (COH1-13) whole type III GBS or with purified bacterial components, including type III capsular polysaccharide (III-PS), group B polysaccharide (GB-PS), lipoteichoic acid (LTA), or peptidoglycan (PG). Lipopolysaccharide from Escherichia coli served as a control. Supernatants were harvested at specific timed intervals, and TNF-alpha levels were measured by enzyme-linked immunosorbent assay. Monocytes exposed to COH1 and COH1-13 induced similar amounts of TNF-alpha. III-PS, GB-PS, LTA, and PG each induced TNF-alpha in a time- and concentration-dependent manner. However, TNF-alpha release was significantly greater after stimulation by the GB-PS or PG than after stimulation by III-PS or LTA (P < 0.05). Our findings indicate that GB-PS and PG are the bacterial cell wall components primarily evoking TNF-alpha release. These, alone or in concert with other factors, may be responsible for septic shock accompanying GBS sepsis. PMID:8945544

Effect of boric acid solution on cartilage metabolism.

PubMed

Benderdour, M; Hess, K; Gadet, M D; Dousset, B; Nabet, P; Belleville, F

1997-05-08

Pelvic cartilage of chick embryo was used to demonstrate that presence of boron in culture medium decreases synthesis of proteoglycans, collagen and total proteins but on the other hand increases the release of these macromolecules. However, when glucose concentration in culture medium is brought to 22mM, the synthesis decrease is no longer observed, whereas release increase persists. Proteins released into the culture medium included heat shock proteins (70 hsp) and tumor necrosis factor alpha (TNF alpha). The amount of phosphorylated proteins was enhanced in presence of boron while endoprotease activity in cartilage and in culture medium was significantly augmented. The in vitro effects of boric acid may explain its in vivo effect on wound healing.

Bladder pain induced by prolonged peripheral alpha 1A adrenoceptor stimulation involves the enhancement of transient receptor potential vanilloid 1 activity and an increase of urothelial adenosine triphosphate release.

PubMed

Matos, R; Cordeiro, J M; Coelho, A; Ferreira, S; Silva, C; Igawa, Y; Cruz, F; Charrua, A

2016-12-01

Pathophysiological mechanisms of chronic visceral pain (CVP) are unknown. This study explores the association between the sympathetic system and bladder nociceptors activity by testing the effect of a prolonged adrenergic stimulation on transient receptor potential vanilloid 1 (TRPV1) activity and on urothelial adenosine triphosphate (ATP) release. Female Wistar rats received saline, phenylephrine (PHE), PHE + silodosin, PHE + naftopidil or PHE + prazosin. TRPV1 knockout and wild-type mice received saline or PHE. Visceral pain behaviour tests were performed before and after treatment. Cystometry was performed, during saline and capsaicin infusion. Fos immunoreactivity was assessed in L6 spinal cord segment. Human urothelial ATP release induced by mechanical and thermal stimulation was evaluated. Subcutaneous, but not intrathecal, PHE administration induced pain, which was reversed by silodosin, a selective alpha 1A adrenoceptor antagonist, but not by naftopidil, a relatively selective antagonist for alpha 1D adrenoceptor. Silodosin also reversed PHE-induced bladder hyperactivity and L6 spinal cord Fos expression. Thus, in subsequent experiments, only silodosin was used. Wild-type, but not TRPV1 knockout, mice exhibited phenylephrine-induced pain. Capsaicin induced a greater increase in voiding contractions in PHE-treated rats than in control animals, and silodosin reversed this effect. When treated with PHE, ATP release from human urothelial cells was enhanced either by mechanical stimulation or by lowering the thermal threshold of urothelial TRPV1, which becomes abnormally responsive at body temperature. This study suggests that the activation of peripheral alpha 1A adrenoceptors induces CVP, probably through its interaction with TRPV1 and ATP release. © 2016 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

Therapeutic Efficacy of Alpha-RIT Using a (213)Bi-Anti-hCD138 Antibody in a Mouse Model of Ovarian Peritoneal Carcinomatosis.

PubMed

Derrien, Aurélie; Gouard, Sébastien; Maurel, Catherine; Gaugler, Marie-Hélène; Bruchertseifer, Frank; Morgenstern, Alfred; Faivre-Chauvet, Alain; Classe, Jean-Marc; Chérel, Michel

2015-01-01

Ovarian peritoneal carcinomatosis is a pathology for which effective cures are currently lacking. New research protocols seek to eradicate residual micrometastases following cytoreductive surgery by using hyperthermic intraperitoneal chemotherapy (HIPEC) or radioimmunotherapy (RIT). This study aims to first develop alpha-RIT using an anti-CD138 mAb radiolabeled with an alpha-emitter, bismuth-213 ((213)Bi-B-B4) and HIPEC in a nude mouse model and second to compare and combine these techniques. A murine model of postoperative ovarian peritoneal carcinomatosis was established. A pilot group of six mice received an intraperitoneal injection of luciferase-tagged SHIN-3 cells and bioluminescence was measured every day. Cytoreductive surgery was performed at day 14 (n = 4) and 29 (n = 2). Because the residual bioluminescence signal measured after surgery was equivalent to that obtained 3 days after the graft, HIPEC or alpha-RIT treatments were applied 3 days after the graft. Ten mice were treated by HIPEC with cisplatine (37.5 mg/mL), 11 with 7.4 MBq of (213)Bi-B-B4, seven with 11.1 MBq of (213)Bi-B-B4, and 10 mice were treated with the combined therapy (HIPEC + 7.4 MBq of (213)Bi-B-B4). Eleven mice received no treatment. Bioluminescence imaging and survival were assessed. Alpha-RIT 7.4 MBq and 11.1 MBq significantly improved survival (p = 0.0303 and p = 0.0070, respectively), whereas HIPEC and HIPEC + alpha-RIT treatments did not significantly ameliorate survival as compared to the control group. Survival was significantly increased by alpha-RIT treatment in mice with peritoneal carcinomatosis of ovarian origin; however, HIPEC alone or in combination with alpha-RIT had no significant effect.

Particles from wood smoke and traffic induce differential pro-inflammatory response patterns in co-cultures

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

Kocbach, Anette; Herseth, Jan Inge; Lag, Marit

2008-10-15

The inflammatory potential of particles from wood smoke and traffic has not been well elucidated. In this study, a contact co-culture of monocytes and pneumocytes was exposed to 10-40 {mu}g/cm{sup 2} of particles from wood smoke and traffic for 12, 40 and 64 h to determine their influence on pro-inflammatory cytokine release (TNF-{alpha}, IL-1, IL-6, IL-8) and viability. To investigate the role of organic constituents in cytokine release the response to particles, their organic extracts and the washed particles were compared. Antagonists were used to investigate source-dependent differences in intercellular signalling (TNF-{alpha}, IL-1). The cytotoxicity was low after exposure tomore » particles from both sources. However, wood smoke, and to a lesser degree traffic-derived particles, induced a reduction in cell number, which was associated with the organic fraction. The release of pro-inflammatory cytokines was similar for both sources after 12 h, but traffic induced a greater release than wood smoke particles with increasing exposure time. The organic fraction accounted for the majority of the cytokine release induced by wood smoke, whereas the washed traffic particles induced a stronger response than the corresponding organic extract. TNF-{alpha} and IL-1 antagonists reduced the release of IL-8 induced by particles from both sources. In contrast, the IL-6 release was only reduced by the IL-1 antagonist during exposure to traffic-derived particles. In summary, particles from wood smoke and traffic induced differential pro-inflammatory response patterns with respect to cytokine release and cell number. Moreover, the influence of the organic particle fraction and intercellular signalling on the pro-inflammatory response seemed to be source-dependent.« less

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

none

This report is the first quarterly report under Contract AT(30-1)-2528 for the decontamination and recovery of precious metals from contaminated scrap. This program encompasses the recovery of gold, platinum, iridium, rhodium and palladium from scrap and contaminated laboratory ware, equipment, etc. which may be contaminated by alpha emitters (i.e., uranium, plutonium and possibly polonium or combinations of these), beta-gamma emitters such as fission products or all three sources of radiation. In addition the scrap can be chemically contaminated by base metals, graphite or other contaminants. Osmium, ruthenium or silver are not to be recovered. Since the scrap can exist inmore » such a great variety of forms such as platinum-rhodium laboratory crucibles, graphite crucibles containing platinum-base metal alloys derived from vacuum fusion baths, insulated thermocouple wires, reactor liners, porous platinum filters, alloys such as Baker alloy 413 (60 Au, 25 Pd, 15 Pt) it may be necessary to devise specific methods for a given type of scrap. Nevertheless the basic chemistry is the same and information and methods applicable to single systems will apply directly to the more complicated ones. Accordingly the relatively simple systems would be investigated first and the more complicated ones later in the program. An essential and major contribution to the success of the program is to devise or adapt accurate and precise analytical chemical techniques for scrap identification, process control, purity of the final products and accountability control. Accordingly, the emphasis on chemical analysis will be proportionally greater during the early stages of the program. The residual activity level to be attained is presently stated at twice the standard deviation obtained in low background counters (alpha {approx}0.1 c/m, beta {approx} 5 c/m) of virgin platinum.« less

Thermal Optical Properties of Lunar Dust Simulants and Their Constituents

NASA Technical Reports Server (NTRS)

Gaier, James R.; Ellis, Shaneise; Hanks, Nichole

2011-01-01

The total reflectance spectra of lunar simulant dusts (< 20 mm particles) were measured in order to determine their integrated solar absorptance (alpha) and their thermal emittance (epsilon) for the purpose of analyzing the effect of dust on the performance of thermal control surfaces. All of the simulants except one had a wavelength-dependent reflectivity (p (lambda)) near 0.10 over the wavelength range of 8 to 25 microns and so are highly emitting at room temperature and lower. The 300 K emittance (epsilon) of all the lunar simulants except one ranged from 0.78 to 0.92. The exception was Minnesota Lunar Simulant 1 (MLS-1), which has little or no glassy component. In all cases the epsilon was lower for the < 20 micron particles than for larger particles reported earlier. There was considerably more variation in the lunar simulant reflectance in the solar spectral range (250 to 2500 nm) than in the thermal infrared. As expected, the lunar highlands simulants were more reflective in this wavelength range than the lunar mare simulants. The integrated solar absorptance (alpha) of the simulants ranged from 0.39 to 0.75. This is lower than values reported earlier for larger particles of the same simulants (0.41 to 0.82), and for representative mare and highlands lunar soils (0.74 to 0.91). Since the of some mare simulants more closely matched that of highlands lunar soils, it is recommended that and values be the criteria for choosing a simulant for assessing the effects of dust on thermal control surfaces, rather than whether a simulant has been formulated as a highlands or a mare simulant.

RANTES release by human airway smooth muscle: effects of prostaglandin E(2) and fenoterol.

PubMed

Lazzeri, N; Belvisi, M G; Patel, H J; Chung, K F; Yacoub, M H; Mitchell, J A

2001-12-21

In human airway smooth muscle cells, the levels of RANTES were increased upon stimulation with interleukin-1beta together with tumour necrosis factor-alpha (TNF-alpha) (10 ng ml(-1) for each). In this study, we have assessed the effects of prostaglandin E(2) and the beta(2)-adrenoceptor agonist, fenoterol on RANTES (regulated upon activation, normal T cell expressed and secreted) release by these cells. The levels of RANTES released by human airway smooth muscle cells were measured after 24 h of treatment. Prostaglandin E(2) and fenoterol, only in presence of a cyclo-oxygenase inhibitor indomethacin (10(-6) M), provoked a concentration-dependent reduction in RANTES release. These data suggest that, in settings where cyclo-oxygenase activity is low, both drugs may relieve the symptoms of airway diseases by reducing RANTES production.

Monoamine uptake inhibitors block alpha7-nAChR-mediated cerebral nitrergic neurogenic vasodilation.

PubMed

Long, Cheng; Chen, Mei-Fang; Sarwinski, Susan J; Chen, Po-Yi; Si, Minliang; Hoffer, Barry J; Evans, M Steven; Lee, Tony J F

2006-07-01

We have proposed that activation of cerebral perivascular sympathetic alpha7-nicotinic acetylcholine receptors (alpha7-nAChRs) by nicotinic agonists releases norepinephrine, which then acts on parasympathetic nitrergic nerves, resulting in release of nitric oxide and vasodilation. Using patch-clamp electrophysiology, immunohistochemistry, and in vitro tissue bath myography, we tested this axo-axonal interaction hypothesis further by examining whether blocking norepinephrine reuptake enhanced alpha7-nAChR-mediated cerebral nitrergic neurogenic vasodilation. The results indicated that choline- and nicotine-induced alpha7-nAChR-mediated nitrergic neurogenic relaxation in endothelium-denuded isolated porcine basilar artery rings was enhanced by desipramine and imipramine at lower concentrations (0.03-0.1 microM) but inhibited at higher concentrations (0.3-10 microM). In cultured superior cervical ganglion (SCG) neurons of the pig and rat, choline (0.1-30 mM)-evoked inward currents were reversibly blocked by 1-30 microM mecamylamine, 1-30 microM methyllycaconitine, 10-300 nM alpha-bungarotoxin, and 0.1-10 microM desipramine and imipramine, providing electrophysiological evidence for the presence of similar functional alpha7-nAChRs in cerebral perivascular sympathetic neurons of pigs and rats. In alpha7-nAChR-expressing Xenopus oocytes, choline-elicited inward currents were attenuated by alpha-bungarotoxin, imipramine, and desipramine. These monoamine uptake inhibitors appeared to directly block the alpha7-nAChR, resulting in diminished nicotinic agonist-induced cerebral nitrergic vasodilation. The enhanced nitrergic vasodilation by lower concentrations of monoamine uptake inhibitors is likely due to a greater effect on monoamine uptake than on alpha7-nAChR blockade. These results further support the hypothesis of axo-axonal interaction in nitrergic regulation of cerebral vascular tone.

Central alpha/sub 2/ adrenergic receptors in the rat cerebral cortex: repopulation kinetics and receptor reserve

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

Adler, C.H.

1986-01-01

The alpha/sub 2/ adrenergic receptor subtype is thought to play a role in the mechanism of action of antidepressant and antihypertensive drugs. This thesis has attempted to shed light on the regulation of central alpha/sub 2/ adrenergic receptors in the rat cerebral cortex. Repopulation kinetics analysis allows for the determination of the rate of receptor production, rate constant of degradation, and half-life of the receptor. This analysis was carried out using both radioligand binding and functional receptor assays at various times following the irreversible inactivation of central alpha/sub 2/ adrenergic receptors by in vivo administration of N-ethoxycarbonyl-2-ethyoxy-1,2-dihydroquinoline (EEDQ). Both alpha/submore » 2/ agonist and antagonist ligand binding sites recovered with a t/sub 1/2/ equal to approximately 4 days. The function of alpha/sub 2/ adrenergic autoreceptors, which inhibit stimulation-evoked release of /sup 3/H-norepinephrine (/sup 3/H-NE) and alpha/sub 2/ adrenergic heteroreceptors which inhibit stimulation-evoked release of /sup 3/H-serotonin (/sup 3/H-5-HT) were assayed. The t/sub 1/2/ for recovery of maximal autoreceptor and heteroreceptor function was 2.4 days and 4.6 days, respectively. The demonstration of a receptor reserve is critical to the interpretation of past and future studies of the alpha/sub 2/ adrenergic receptor since it demonstrates that: (1) alterations in the number of alpha/sub 2/ adrenergic receptor binding sites cannot be extrapolated to the actual function of the alpha/sub 2/ adrenergic receptor; and (2) alterations in the number of alpha/sub 2/ receptors is not necessarily accompanied by a change in the maximum function being studied, but may only result in shifting of the dose-response curve.« less

Preliminary results from the lunar prospector alpha particle spectrometer

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

Lawson, S. L.

2001-01-01

The Lunar Prospector Alpha Particle Spectrometer (LP APS) builds on Apollo heritage and maps the distribution of outgassing sites on the Moon. The APS searches for lunar surface gas release events and maps their distribution by detecting alpha particles produced by the decay of gaseous radon-222 (5.5 MeV, 3.8 day half-life) and solid polonium-210 (5.3 MeV, 138 day half-life, but remains on the surface with a 21 year half-life as lead-210), which are radioactive daughters from the decay of uranium-238. Radon is in such small quantities that it is not released directly from the lunar interior, rather it is entrainedmore » in a stream of gases and serves as a tracer for such gases. Once released, the radon spreads out by 'bouncing' across the surface on ballistic trajectories in a random-walk process. The 3.8 day half-life of radon-222 allows the gas to spread out by several 100 km before it decays and allows the APS to detect gas release events up to a few days after they occur. The long residence time (10s of years) of the lead-210 precursor to the polonium-210 allows the mapping of gas vents which have been active over the last approximately 50 years. Because radon and polonium are daughter products of the decay of uranium, the background level of alpha particle activity is a function of the lunar crustal uranium distribution. Using radioactive radon and polonium as tracers, the Apollo 15 and 16 Command Module orbital alpha particle experiments obtained evidence for the release of gases at several sites beneath the orbit tracks, especially over the Aristarchus Plateau and Mare Fecunditatis [1]. Aristarchus crater had previously been identified by ground-based observers as the site of transient optical events [2]. The Apollo 17 surface mass spectrometer showed that argon-40 is released from the lunar interior every few months, apparently in concert with some of the shallow moonquakes that are believed to be of tectonic origin [3]. The latter tectonic events could be associated with very young scarps identified in the lunar highlands [4] and are believed to indicate continued global contraction. Such quakes could open fissures leading to the release of gases that are trapped below the surface. The detection of radon-222 outgassing events at the margins of Fecunditatis basin was surprising because the observed surface distribution of uranium and thorium do not extend sufficiently eastward to cover Fecunditatis. If the Apollo detections prove sound, then those alpha particle emissions indicate substantial subsurface concentrations of uranium-238 within Fecunditatis. A primary goal of the APS was to map gas-release events, thus allowing both an appraisal of the current level of tectonic activity on the Moon and providing a probe of subsurface uranium concentrations.« less

alpha2-Adrenoceptors control the release of noradrenaline but not neuropeptide Y from perivascular nerve terminals.

PubMed

Donoso, M Veronica; Carvajal, Andrés; Paredes, Alfonso; Tomic, Alexander; Koenig, Cecilia S; Huidobro-Toro, J Pablo

2002-09-01

Neuropeptide Y (NPY) and noradrenaline (NA) are co-transmitters at many sympathetic synapses, but it is not yet clear if their release is independently regulated. To address this question, we quantified the electrically evoked release of these co-transmitters from perivascular nerve terminals to the mesenteric circulation in control and drug-treated rats. 6-Hydroxydopamine reduced the tissue content and the electrically evoked release of ir-NPY and NA as well as the rise in perfusion pressure. A 0.001 mg/kg reserpine reduced the content of ir-NPY and NA, but did not modify their release nor altered the rise in perfusion pressure elicited by the electrical stimuli. However, 0.1mg/kg reserpine reduced both the content and release of NA but decreased only the content but not the release of ir-NPY; the rise in perfusion pressure was halved. Clonidine did not affect the release of ir-NPY while it lowered the outflow of NA, not altering the rise in perfusion pressure elicited by the electrical stimuli. Yohimbine, did not modify the release of ir-NPY but increased the NA outflow, it antagonized the clonidine effect. Therefore, presynaptic alpha2-adrenoceptors modulate the release of NA but not NPY, implying separate regulatory mechanisms.

Extreme [O III] Emitters at z ∼ 0.5

NASA Astrophysics Data System (ADS)

Li, Zhihui; Malkan, Matthew A.

2018-06-01

We have found a sample of extreme emission-line galaxies (EELGs) with strong [O III]λ5007 emission at z ∼ 0.5. Using broadband photometric selection and requiring small uncertainties in photometry, we searched the 14th Data Release of the Sloan Digital Sky Survey (SDSS) and found 2658 candidates with strong i-band excess (i – z ≤ r – i – 0.7). We further obtained 649 SDSS spectra of these objects, and visually identified 22 [O III] emitters lying at 0.40 < z < 0.63. Having constructed their ultraviolet–infrared spectral energy distributions, we found that they have fairly blue r – W2 and red W1 – W4 colors, indicative of strong, warm dust emission. Their rest-frame [O III]λ5007 equivalent widths are mostly 200–600 Å, and their high [O III]λ5007/Hβ ratios put them at the boundary of star-forming galaxies and active galactic nuclei on line ratio classification diagrams. The typical E(B–V) and electron temperature of [O III] emitters are ∼0.1–0.3 mag and ∼104 K, respectively. The lowest metallicity of our [O III] emitters with S/N[O III]λ4363 > 3 is 12 + log(O/H) = {7.98}-0.02+0.12, with a median value of {8.24}-0.04+0.05. Our [O III] emitters exhibit remarkably high line luminosity—18/22 have L [O III]λ5007 > 5 × 1042 erg s‑1 and 5/22 have L [O III]λ5007 > 1043 erg s‑1. Their estimated volume number density at z ∼ 0.5 is ∼2 × 10‑8 Mpc‑3, with L [O III]λ5007 down to ∼3 × 1042 erg s‑1. The cumulative number distribution of EELGs across different redshifts is indicative of a strong redshift evolution at the bright end of the [O III] luminosity function.

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

Marfa-Riera, V.; Gollin, D.; Mohnen, D.

An optimized tobacco thin-cell-layer (TCL) bioassay was used to study the induction of flowers by plant oligosaccharins. Endopolygalacturonase (EPG)-released fragments of suspension-cultured sycamore cell walls induced flowers on TCLs grown on a medium containing 1.5 {mu}M IBA and 0.9 {mu}M kinetin. The EPG-released fragments were primarily composed of the polysaccharides rhamnogalacturonan I (RG-I), rhamnogalacturonan II (RG-II), and {alpha}-1,4-linked oligogalacturonides. The {alpha}-1,4-linked oligogalacturonides, subsequently purified from the EPG-released sycamore cell wall fragment mixture, induced flowers on TCLs. Purified RG-I and RG-II did not induce flowers. Oligosaccharide fragments, generated by partial acid hydrolysis of citrus pectin, were also capable of inducing flowersmore » on the TCLs. The active components in the pectin fragment mixture were {alpha}-1,4-linked oligogalacturonides. Oligogalacturonides with a degree of polymerization (DP) of 8-16, at concentrations of {approx} 0.1 {mu}M, induced flowers, while oligogalacturonides with a DP 2-7, even at higher concentrations, did not. Oligogalacturonides have previously been shown to induce the synthesis of phytoalexins, protease inhibitors, lignin, and ethylene in other plant systems. Thus, the ability of {alpha}-1,4-linked oligogalacturonides to induce flower formation in the tobacco TCLs represents a new biological activity of these oligosaccharins.« less

Noradrenaline inhibits lipopolysaccharide-induced tumor necrosis factor and interleukin 6 production in human whole blood.

PubMed Central

van der Poll, T; Jansen, J; Endert, E; Sauerwein, H P; van Deventer, S J

1994-01-01

Sepsis and lipopolysaccharide (LPS) trigger the systemic release of both cytokines and catecholamines. Cytokines are known to be capable of eliciting a stress hormone response in vivo. The present study sought insight into the effect of noradrenaline on LPS-induced release of tumor necrosis factor alpha (TNF) and interleukin 6 (IL-6) in human whole blood. Whole blood was incubated with LPS for 4 h at 37 degrees C in the presence and absence of noradrenaline and/or specific alpha and beta antagonists and agonists. Noradrenaline caused a dose-dependent inhibition of LPS-induced TNF and IL-6 production. This effect could be completely prevented by addition of the specific beta 1, antagonist metoprolol, while it was not affected by the alpha antagonist phentolamine. Specific beta-adrenergic stimulation by isoprenaline mimicked the inhibiting effect of noradrenaline on LPS-evoked cytokine production, whereas alpha-adrenergic stimulation by phenylephrine had no effect. Fluorescence-activated cell sorter analysis demonstrated that beta-adrenergic stimulation had no effect on LPS binding to and internalization into mononuclear cells or on the expression of CD14, the major receptor for LPS on mononuclear cells. In acute sepsis, enhanced release of noradrenaline may be part of a negative feedback mechanism meant to inhibit ongoing TNF and IL-6 production. PMID:8168970

Immune-endocrine interactions in the mammalian adrenal gland: facts and hypotheses.

PubMed

Nussdorfer, G G; Mazzocchi, G

1998-01-01

Several cytokines, which are the major mediators of the inflammatory responses, are well-known to stimulate the hypothalamopituitary corticotropin-releasing hormone (CRH)/adrenocorticotropic hormone (ACTH) system, thereby evoking secretory responses by the adrenal cortex. Many of these cytokines, including interleukin-1 (IL-1), IL-2, IL-6, tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (INF-gamma) are synthesized in the adrenal gland by both parenchymal cells and resident macrophages, and the release of some of them (e.g., IL-6 and TNF-alpha) is regulated by the main agonists of steroid hormone secretion (e.g., ACTH and angiotensin-II) and bacterial endotoxins. Adrenocortical and adrenomedullary cells are provided with specific receptors for IL-1, IL-2, and IL-6. IL-1 and TNF-alpha directly inhibit aldosterone secretion of zona glomerulosa cells, whereas IL-6 enhances it. IL-2, IL-3, IL-6, and INF-alpha are able to directly stimulate glucocorticoid production by zona fasciculata and zona reticularis cells, whereas IL-1 exerts an analogous effect through an indirect mechanism involving the stimulation of catecholamine release by chromaffin cells and/or the activation of the intramedullary CRH/ACTH system; again, TNF-alpha depresses glucocorticoid synthesis. IL-6 raises androgen secretion by inner adrenocortical layers. IL-1 enhances the proliferation of adrenocortical cells, and findings suggest that cytokines may control the apoptotic deletion of senescent zona reticularis cells. The relevance of the intraadrenal cytokine system in the fine-tuning of the secretion and growth of the adrenal cortex under normal conditions remains to be explored. However, indirect proof is available that local immune-endocrine interactions may play an important role in modulating adrenal responses to inflammatory and immune challenges and stresses.

Co-operative actions and degradation analysis of purified xylan-degrading enzymes from Thermomonospora fusca BD25 on oat-spelt xylan.

PubMed

Tuncer, M; Ball, A S

2003-01-01

To determine and quantify the products from the degradation of xylan by a range of purified xylan-degrading enzymes, endoxylanase, beta-xylosidase and alpha-l-arabinofuranosidase produced extracellularly by Thermomonospora fusca BD25. The amounts of reducing sugars released from oat-spelt xylan by the actions of endoxylanase, beta-xylosidase and alpha-l-arabinofuranosidase were equal to 28.1, 4.6 and 7% hydrolysis (as xylose equivalents) of the substrate used, respectively. However, addition of beta-xylosidase and alpha-l-arabinofuranosidase preparation to endoxylanase significantly enhanced (70 and 20% respectively) the action of endoxylanase on the substrate. The combination of purified endoxylanase, beta-xylosidase and alpha-l-arabinofuranosidase preparations produced a greater sugar yield (58.6% hydrolysis) and enhanced the total reducing sugar yield by around 50%. The main xylooligosaccharide products released using the action of endoxylanase alone on oat-spelt xylan were identified as xylobiose and xylopentose. alpha-l-Arabinofuranosidase was able to release arabinose and xylobiose from oat-spelt xylan. In the presence of all three purified enzymes the hydrolysis products of oat-spelt xylan were mainly xylose, arabinose and substituted xylotetrose with lesser amount of substituted xylotriose. The addition of the beta-xylosidase and alpha-l-arabinofuranosidase enzymes to purified xylanases more than doubled the degradation of xylan from 28 to 58% of the total substrate with xylose and arabinose being the major sugars produced. The results highlight the role of xylan de-branching enzymes in the degradation of xylan and suggest that the use of enzyme cocktails may significantly improve the hydrolysis of xylan in industrial processes.

Manipulation of norepinephrine metabolism with yohimbine in the treatment of autonomic failure

NASA Technical Reports Server (NTRS)

Biaggioni, I.; Robertson, R. M.; Robertson, D.

1994-01-01

It has been postulated that alpha 2-adrenergic receptors play a modulatory role in the regulation of blood pressure. Activation of alpha 2-receptors located in the central nervous system results in inhibition of sympathetic tone and decrease of blood pressure. This indeed may be the mechanism of action of central sympatholytic antihypertensives such as alpha-methyldopa. Presynaptic alpha 2-receptors also are found in adrenergic nerve terminals. These receptors act as a negative feedback mechanism by inhibiting the release of norepinephrine. The relevance of alpha 2-adrenergic receptors for blood pressure regulation can be explored with yohimbine, a selective antagonist of these receptors. Yohimbine increases blood pressure in resting normal volunteers. This effect is associated with an increase in both sympathetic nerve activity, reflecting an increase in central sympathetic outflow, and in norepinephrine spillover, reflecting potentiation of the release of norepinephrine from adrenergic nerve terminals. These actions, therefore, underscore the importance of alpha 2-adrenergic receptors for blood pressure regulation even under resting conditions. Patients with autonomic failure, even those with severe sympathetic deprivation, are hypersensitive to the pressor effects of yohimbine. This increased responsiveness can be explained by sensitization of adrenergic receptors, analogous to denervation supersensitivity, and by the lack of autonomic reflexes that would normally buffer any increase in blood pressure. Preliminary studies suggest that the effectiveness of yohimbine in autonomic failure can be enhanced with monoamine oxidase inhibitors. Used in combination, yohimbine increases norepinephrine release, whereas monoamine oxidase inhibitors inhibit its degradation. Therefore, yohimbine is not only a useful tool in the study of blood pressure regulation, but may offer a therapeutic option in autonomic dysfunction.

Tip-alpha (hp0596 gene product) is a highly immunogenic Helicobacter pylori protein involved in colonization of mouse gastric mucosa.

PubMed

Godlewska, Renata; Pawlowski, Marcin; Dzwonek, Artur; Mikula, Michal; Ostrowski, Jerzy; Drela, Nadzieja; Jagusztyn-Krynicka, Elzbieta K

2008-03-01

A product of the Helicobacter pylori hp0596 gene (Tip-alpha) is a highly immunogenic homodimeric protein, unique for this bacterium. Cell fractionation experiments indicate that Tip-alpha is anchored to the inner membrane. In contrast, the three-dimensional model of the protein suggests that Tip-alpha is soluble or, at least, largely exposed to the solvent. hp0596 gene knockout resulted in a significant decrease in the level of H. pylori colonization as measured by real-time PCR assay. In addition, the Tip-alpha recombinant protein was determined to stimulate macrophage to produce IL-1alpha and TNF-alpha. Both results imply that Tip-alpha is rather loosely connected to the inner membrane and potentially released during infection.

Rapid determination of alpha emitters using Actinide resin.

PubMed

Navarro, N; Rodriguez, L; Alvarez, A; Sancho, C

2004-01-01

The European Commission has recently published the recommended radiological protection criteria for the clearance of building and building rubble from the dismantling of nuclear installations. Radionuclide specific clearance levels for actinides are very low (between 0.1 and 1 Bq g(-1)). The prevalence of natural radionuclides in rubble materials makes the verification of these levels by direct alpha counting impossible. The capability of Actinide resin (Eichrom Industries, Inc.) for extracting plutonium and americium from rubble samples has been tested in this work. Besides a strong affinity for actinides in the tri, tetra and hexavalent oxidation states, this extraction chromatographic resin presents an easy recovery of absorbed radionuclides. The retention capability was evaluated on rubble samples spiked with certified radionuclide standards (239Pu and 241Am). Samples were leached with nitric acid, passed through a chromatographic column containing the resin and the elution fraction was measured by LSC. Actinide retention varies from 60% to 80%. Based on these results, a rapid method for the verification of clearance levels for actinides in rubble samples is proposed.

Removal of Long-Lived Radon Daughters by Electropolishing Thin Layers of Stainless Steel

NASA Astrophysics Data System (ADS)

White, James; Schnee, Richard; Bunker, Raymond; Bowles, Michael; Cushman, Priscilla; Epland, Matthew; Pepin, Mark; Guiseppe, Vince

2012-10-01

Long-lived alpha and beta emitters in the Radon decay chain on detector surfaces may be limiting background in many experiments attempting to detect dark matter or neutrinoless double beta decay. To screen detector surfaces for this radioactive contamination, a low-radiation, multi-wire proportional chamber (the BetaCage) is under construction. Removal of Pb-210 implanted on its 25-micron stainless steel wires without causing significant variation in the diameter of the wires is critical to the BetaCage's ultimate sensitivity. An apparatus to perform electropolishing trials to remove roughly a micron of material has been assembled. These trials have shown promising results. Stainless steel square samples implanted with Pb-210 have shown counts with a reduction factor greater than 10 after electropolishing according to gamma assay. Furthermore, alpha counting has produced similar results, with a reduction factor greater than 100. Lastly, the diameters of wires after electropolishing have remained sufficiently uniform, with reduction in thickness consistent with expectations.

Large area, low cost space solar cells with optional wraparound contacts

NASA Technical Reports Server (NTRS)

Michaels, D.; Mendoza, N.; Williams, R.

1981-01-01

Design parameters for two large area, low cost solar cells are presented, and electron irradiation testing, thermal alpha testing, and cell processing are discussed. The devices are a 2 ohm-cm base resistivity silicon cell with an evaporated aluminum reflector produced in a dielectric wraparound cell, and a 10 ohm-cm silicon cell with the BSF/BSR combination and a conventional contact system. Both cells are 5.9 x 5.9 cm and require 200 micron thick silicon material due to mission weight constraints. Normalized values for open circuit voltage, short circuit current, and maximum power calculations derived from electron radiation testing are given. In addition, thermal alpha testing values of absorptivity and emittance are included. A pilot cell processing run produced cells averaging 14.4% efficiencies at AMO 28 C. Manufacturing for such cells will be on a mechanized process line, and the area of coverslide application technology must be considered in order to achieve cost effective production.

Interpreting HST observations with simulations of reionization: the ionizing photon budget and the decline of Lyman-alpha emission in z>6 dropouts

NASA Astrophysics Data System (ADS)

D'Aloisio, Anson

2017-08-01

In recent years, HST surveys such as CANDELS, HUDF, BoRG/HIPPIES, ERS, and the Frontier Fields, have made possible the first robust measurements of the rest-frame UV luminosity function of z =6-10 galaxies, spanning much of the redshift range over which reionization likely occurred. These measurements provide an estimate of the galactic ionizing photon output, addressing the critical question of whether these galaxies could have reionized the Universe. In addition, follow-up spectroscopy has measured the fraction of these galaxies that show Lyman-alpha emission. Interestingly, a dramatic decrease in this fraction above z 6 has been observed, and this evolution has (controversially) been interpreted as evidence that much of reionization happened over z=6-8 (as intergalactic neutral gas leads to large damping wings that scatter the Lyman-alpha line). The clumpiness of the IGM and how it self shields to ionizing photons impacts whether the observed population of galaxies can reionize the Universe, as well as the interpretation of the evolving Lyman-alpha emitter fraction. We propose to run fully coupled radiative-hydrodynamics simulations that are the first to resolve the evaporation of small structures by passing ionization fronts and, hence, to accurately assess the level of clumpiness and self-shielding from the IGM. Our study will nail down the clumping factor used to assess whether the observed population of galaxies can drive reionization, and it will address whether neutral self-shielding clumps in recently reionized regions can scatter galaxies' Lyman-alpha lines.

Effects of synthetic sphingosine-1-phosphate analogs on cytosolic phospholipase A2alpha-independent release of arachidonic acid and cell toxicity in L929 fibrosarcoma cells: the structure-activity relationship.

PubMed

Shimizu, Masaya; Muramatsu, Yuki; Tada, Eiko; Kurosawa, Takeshi; Yamaura, Erika; Nakamura, Hiroyuki; Fujino, Hiromichi; Houjyo, Yuuya; Miyasaka, Yuri; Koide, Yuuki; Nishida, Atsushi; Murayama, Toshihiko

2009-03-01

Sphingolipid metabolites including ceramide, sphingosine, and their phosphorylated products [sphingosine-1-phosphate (S1P) and ceramide-1-phosphate] regulate cell functions including arachidonic acid (AA) metabolism and cell death. The development of analogs of S1P may be useful for regulating these mediator-induced cellular responses. We synthesized new analogs of S1P and examined their effects on the release of AA and cell death in L929 mouse fibrosarcoma cells. Among the analogs tested, several compounds including DMB-mC11S [dimethyl (2S,3R)-2-tert-butoxycarbonylamino-3-hydroxy-3-(3'-undecyl)phenylpropyl phosphate] and DMB-mC9S [dimethyl (2S,3R)-2-tert-butoxycarbonylamino-3-hydroxy-3-(3'-nonyl)phenylpropyl phosphate] released AA within 1 h and caused cell death 6 h after treatment. The release of AA was observed in C12 cells [a L929 variant lacking a type alpha cytosolic phospholipase A(2) (cPLA(2)alpha)] and L929-cPLAalpha-siRNA cells (L929 cells treated with small interference RNA for cPLA(2)alpha). Treatment with pharmacological inhibitors of secretory and Ca(2+)-independent PLA(2)s decreased the DMB-mC11S-induced release of AA. The effect of the S1P analogs tested on the release of AA was comparable to that on cell death in L929 cells, and a high correlation coefficient was observed. Two analogs lacking a butoxycarbonyl moiety [DMAc-mC11S (dimethyl (2S,3R)-2-acetamino-3-hydroxy-3-(3'-undecyl)phenylpropyl phosphate] and DMAm-mC11S [dimethyl (2S,3R)-2-amino-3-hydroxy-3-(3'-undecyl)phenylpropyl phosphate)] had inhibitory effects on the release of AA and cell toxicity induced by DMB-mC11S. Synthetic phosphorylated lipid analogs may be useful for studying PLA(2) activity and its toxicity in cells. [Supplementary Fig. 1: available only at http://dx.doi.org/10.1254/jphs.08284FP].

A 16 deg2 survey of emission-line galaxies at z < 1.5 in HSC-SSP Public Data Release 1

NASA Astrophysics Data System (ADS)

Hayashi, Masao; Tanaka, Masayuki; Shimakawa, Rhythm; Furusawa, Hisanori; Momose, Rieko; Koyama, Yusei; Silverman, John D.; Kodama, Tadayuki; Komiyama, Yutaka; Leauthaud, Alexie; Lin, Yen-Ting; Miyazaki, Satoshi; Nagao, Tohru; Nishizawa, Atsushi J.; Ouchi, Masami; Shibuya, Takatoshi; Tadaki, Ken-ichi; Yabe, Kiyoto

2018-01-01

We present initial results from the Subaru Strategic Program (SSP) with Hyper Suprime-Cam (HSC) on a comprehensive survey of emission-line galaxies at z < 1.5 based on narrowband imaging. The first Public Data Release provides us with data from two narrowband filters, specifically NB816 and NB921 over 5.7 deg2 and 16.2 deg2 respectively. The 5 σ limiting magnitudes are 25.2 mag (UltraDeep layer, 1.4 deg2) and 24.8 mag (Deep layer, 4.3 deg2) for NB816, and 25.1 mag (UltraDeep, 2.9 deg2) and 24.6-24.8 mag (Deep, 13.3 deg2) for NB921. The wide-field imaging allows us to construct unprecedentedly large samples of 8054 H α emitters at z ≈ 0.25 and 0.40, 8656 [O III] emitters at z ≈ 0.63 and 0.84, and 16877 [O II] emitters at z ≈ 1.19 and 1.47. We map the cosmic web on scales out to about 50 comoving Mpc that includes galaxy clusters, identified by red sequence galaxies, located at the intersection of filamentary structures of star-forming galaxies. The luminosity functions of emission-line galaxies are measured with precision and are consistent with published studies. The wide field coverage of the data enables us to measure the luminosity functions up to brighter luminosities than previous studies. The comparison of the luminosity functions between the different HSC-SSP fields suggests that a survey volume of >5 × 105 Mpc3 is essential to overcome cosmic variance. Since the current data have not reached the full depth expected for the HSC-SSP, the color cut in i - NB816 or z - NB921 induces a bias towards star-forming galaxies with large equivalent widths, primarily seen in the stellar mass functions for the H α emitters at z ≈ 0.25-0.40. Even so, the emission-line galaxies clearly cover a wide range of luminosity, stellar mass, and environment, thus demonstrating the usefulness of the narrowband data from the HSC-SSP for investigating star-forming galaxies at z < 1.5.

Two cofactors and cytoplasmic chaperonin are required for the folding of alpha- and beta-tubulin.

PubMed Central

Gao, Y; Vainberg, I E; Chow, R L; Cowan, N J

1993-01-01

Though the chaperonins that mediate folding in prokaryotes, mitochondria, and chloroplasts have been relatively well characterized, the folding of proteins in the eukaryotic cytosol is much less well understood. We recently identified a cytoplasmic chaperonin as an 800-kDa multisubunit toroid which forms a binary complex with unfolded actin; the correctly folded polypeptide is released upon incubation with Mg-ATP (Y. Gao, J. O. Thomas, R. L. Chow, G.-H. Lee, and N. J. Cowan, Cell 69:1043-1050, 1992). Here we show that the same chaperonin also forms a binary complex with unfolded alpha- or beta-tubulin; however, there is no detectable release of the correctly folded product, irrespective of the concentration of added Mg-ATP and Mg-GTP or the presence of added carrier tubulin heterodimers with which newly folded alpha- or beta-tubulin polypeptides might exchange. Rather, two additional protein cofactors are required for the generation of properly folded alpha- or beta-tubulin, which is then competent for exchange into preexisting alpha/beta-tubulin heterodimers. We show that actin and tubulins compete efficiently with one another for association with cytoplasmic chaperonin complexes. These data imply that actin and alpha- and beta-tubulin interact with the same site(s) on chaperonin complexes. Images PMID:8096061

Dissociation of branched-chain alpha-keto acid dehydrogenase kinase (BDK) from branched-chain alpha-keto acid dehydrogenase complex (BCKDC) by BDK inhibitors.

PubMed

Murakami, Taro; Matsuo, Masayuki; Shimizu, Ayako; Shimomura, Yoshiharu

2005-02-01

Branched-chain alpha-keto acid dehydrogenase kinase (BDK) phosphorylates and inactivates the branched-chain alpha-keto acid dehydrogenase complex (BCKDC), which is the rate-limiting enzyme in the branched-chain amino acid catabolism. BDK has been believed to be bound to the BCKDC. However, recent our studies demonstrated that protein-protein interaction between BDK and BCKDC is one of the factors to regulate BDK activity. Furthermore, only the bound form of BDK appears to have its activity. In the present study, we examined effects of BDK inhibitors on the amount of BDK bound to the BCKDC using rat liver extracts. The bound form of BDK in the extracts of liver from low protein diet-fed rats was measured by an immunoprecipitation pull down assay with or without BDK inhibitors. Among the BDK inhibitors. alpha-ketoisocaproate, alpha-chloroisocaproate, and a-ketoisovalerate released the BDK from the complex. Furthermore, the releasing effect of these inhibitors on the BDK appeared to depend on their inhibition constants. On the other hand, clofibric acid and thiamine pyrophosphate had no effect on the protein-protein interaction between two enzymes. These results suggest that the dissociation of the BDK from the BCKDC is one of the mechanisms responsible for the action of some inhibitors to BDK.

Neural control of renal function: role of renal alpha adrenoceptors.

PubMed

DiBona, G F

1985-01-01

Adrenoceptors of various subtypes mediate the renal functional responses to alterations in efferent renal sympathetic nerve activity, the neural component, and renal arterial plasma catecholamine concentrations, the humoral component, of the sympathoadrenergic nervous system. Under normal physiologic as well as hypertensive conditions, the influence of the renal sympathetic nerves predominates over that of circulating plasma catecholamines. In most mammalian species, increases in efferent renal sympathetic nerve activity elicit renal vasoconstrictor responses mediated predominantly by renal vascular alpha-1 adrenoceptors, increases in renin release mediated largely by renal juxtaglomerular granular cell beta-1 adrenoceptors with involvement of renal vascular alpha-1 adrenoceptors only when renal vasoconstriction occurs, and direct increases in renal tubular sodium and water reabsorption mediated predominantly by renal tubular alpha-1 adrenoceptors. In most mammalian species, alpha-2 adrenoceptors do not play a significant role in the renal vascular or renin release responses to renal sympathoadrenergic stimulation. Although renal tubular alpha-2 adrenoceptors do not mediate the increases in renal tubular sodium and water reabsorption produced by increases in efferent renal sympathetic nerve activity, they may be involved through their inhibitory effect on adenylate cyclase in modulating the response to other hormonal agents that influence renal tubular sodium and water reabsorption via stimulation of adenylate cyclase.

Enhanced adhesion of films to semiconductors or metals by high energy bombardment

NASA Technical Reports Server (NTRS)

Tombrello, Thomas A. (Inventor); Qiu, Yuanxun (Inventor); Mendenhall, Marcus H. (Inventor)

1985-01-01

Films (12) of a metal such as gold or other non-insulator materials are firmly bonded to other non-insulators such as semiconductor substrates (10), suitably silicon or gallium arsenide by irradiating the interface with high energy ions. The process results in improved adhesion without excessive doping and provides a low resistance contact to the semiconductor. Thick layers can be bonded by depositing or doping the interfacial surfaces with fissionable elements or alpha emitters. The process can be utilized to apply very small, low resistance electrodes (78) to light-emitting solid state laser diodes (60) to form a laser device 70.

Laser-produced lithium plasma as a narrow-band extended ultraviolet radiation source for photoelectron spectroscopy.

PubMed

Schriever, G; Mager, S; Naweed, A; Engel, A; Bergmann, K; Lebert, R

1998-03-01

Extended ultraviolet (EUV) emission characteristics of a laser-produced lithium plasma are determined with regard to the requirements of x-ray photoelectron spectroscopy. The main features of interest are spectral distribution, photon flux, bandwidth, source size, and emission duration. Laser-produced lithium plasmas are characterized as emitters of intense narrow-band EUV radiation. It can be estimated that the lithium Lyman-alpha line emission in combination with an ellipsoidal silicon/molybdenum multilayer mirror is a suitable EUV source for an x-ray photoelectron spectroscopy microscope with a 50-meV energy resolution and a 10-mum lateral resolution.

HEPC-based liposomes trigger cytokine release from peripheral blood cells: effects of liposomal size, dose and lipid composition.

PubMed

Yamamoto, Sayaka; Ishida, Tatsuhiro; Inoue, Akiko; Mikami, Junko; Muraguchi, Masahiro; Ohmoto, Yasukazu; Kiwada, Hiroshi

2002-04-02

The immune response caused by liposome stimulation was studied by assessing the level of several cytokines released from human peripheral blood cells. Liposome stimulation resulted in the release of IL-6, IL-10, IL-1beta, TNF-alpha and IFN-gamma. The size of the liposomes affected the degree of the cytokine releases with larger sized liposomes causing higher levels of cytokine induction. In addition, it appears that the lipid composition of liposomes had no effect on the degree of cytokine release. The release of cytokines occurred even in the absence of serum, suggesting that serum proteins did not contribute to liposome stimulation in peripheral blood cells. The release of cytokines induced by liposome stimulation was inhibited by the presence of either protein kinase-C (PKC) or protein tyrosine kinase (PTK) inhibitor, but not by the presence of an endocytosis inhibitor. This indicates that signal transduction via PKC or PTK is necessary, in order for human peripheral blood cells to release cytokines (IL-6, IL-10, IL-1beta, TNF-alpha and IFN-gamma) as the result of liposome stimulation. These quantitative data on the release of cytokines by liposomal stimulation provide useful information for the development of rational drug delivery systems and the safety of cytokine induction via the use of liposomes.

Ambient Temperature Phase Change Launcher

DTIC Science & Technology

2013-09-30

microwave emitter is activated simultaneously with the release of the gas into the tube. Dkt . No. 100903 Application No. ?? REPLACEMENT SHEET? /31...100 26 24 22 20 18 16 1214 10 FIG. 1 A Dkt . No. 100903 Application No. ?? REPLACEMENT SHEET? /32 STORE ATMOSPHERIC GAS IN LIQUID STATE LAUNCH MISSILE...FROM SUBMARINE BY VAPORIZING THE GAS ADD HEAT TO LIQUID DURING LAUNCH TO MAINTAIN EVAPORATION 50 FIG. 2 52 54 Dkt . No. 100903 Application No

Review of Gallium-68 PSMA PET/CT Imaging in the Management of Prostate Cancer

PubMed Central

Lenzo, Nat P.; Meyrick, Danielle; Turner, J. Harvey

2018-01-01

Over 90% of prostate cancers over-express prostate specific membrane antigen (PSMA) and these tumor cells may be accurately targeted for diagnosis by 68Ga-PSMA-positron emission tomography/computed tomography (68Ga-PSMA-PET/CT) imaging. This novel molecular imaging modality appears clinically to have superseded CT, and appears superior to MR imaging, for the detection of metastatic disease. 68Ga-PSMA PET/CT has the ability to reliably stage prostate cancer at presentation and can help inform an optimal treatment approach. Novel diagnostic applications of 68Ga-PSMA PET/CT include guiding biopsy to improve sampling accuracy, and guiding surgery and radiotherapy. In addition to facilitating the management of metastatic castrate resistant prostate cancer (mCRPC), 68Ga-PSMA can select patients who may benefit from targeted systemic radionuclide therapy. 68Ga-PSMA is the diagnostic positron-emitting theranostic pair with the beta emitter Lutetium-177 PSMA (177Lu-PSMA) and alpha-emitter Actinium-225 PSMA (225Ac-PSMA) which can both be used to treat PSMA-avid metastases of prostate cancer in the molecular tumor-targeted approach of theranostic nuclear oncology. PMID:29439481

Direct evidence for Lyboldsymbol{alpha } depletion in the protocluster core

NASA Astrophysics Data System (ADS)

Shimakawa, Rhythm; Kodama, Tadayuki; Hayashi, Masao; Tanaka, Ichi; Matsuda, Yuichi; Kashikawa, Nobunari; Shibuya, Takatoshi; Tadaki, Ken-ichi; Koyama, Yusei; Suzuki, Tomoko L.; Yamamoto, Moegi

2017-06-01

We have carried out panoramic Lyα narrow-band imaging with Suprime-Cam on Subaru towards the known protocluster USS1558-003 at z = 2.53. Our previous narrow-band imaging in the near-infrared identified multiple dense groups of Hα emitters (HAEs) within the protocluster. We have now identified the large-scale structures across a ˜50 comoving Mpc scale traced by Lyα emitters (LAEs) in which the protocluster traced by the HAEs is embedded. On a smaller scale, however, there are remarkably few LAEs in the regions of HAE overdensities. Moreover, the stacking analyses of the images show that HAEs in higher-density regions show systematically lower escape fractions of Lyα photons than those of HAEs in lower-density regions. These phenomena may be driven by the extra depletion of Lyα emission lines along our line of sight by more intervening cold circumgalactic/intergalactic medium and/or dust in the dense core. We also caution that all the previous high-z protocluster surveys using LAEs as tracers would have largely missed galaxies in the very dense cores of the protoclusters where we would expect to see any early environmental effects.

Evaluation of guggulipid and nimesulide on production of inflammatory mediators and GFAP expression in LPS stimulated rat astrocytoma, cell line (C6).

PubMed

Niranjan, Rituraj; Kamat, Pradeep Kumar; Nath, Chandishwar; Shukla, Rakesh

2010-02-17

The present study was designed to investigate effect of guggulipid, a drug developed by CDRI and nimesulide on LPS stimulated neuroinflammatory changes in rat astrocytoma cell line (C6). Rat astrocytoma cells (C6) were stimulated with LPS (10 microg/ml) alone and in combinations with different concentrations of guggulipid or nimesulide for 24h of incubation. Nitrite release in culture supernatant, ROS in cells, expressions of COX-2, GFAP and TNF-alpha in cell lysate were estimated. LPS (10 microg/ml) stimulated C6 cells to release nitrite, ROS generation, up regulated COX-2 and GFAP expressions at protein level and TNF-alpha at mRNA level. Both guggulipid and nimesulide significantly attenuated nitrite release, ROS generation and also down regulated expressions of COX-2, GFAP and TNF-alpha. Guggulipid and nimesulide per se did not have any significant effect on C6 cells. Results demonstrate the anti-inflammatory effect of guggulipid comparable to nimesulide which suggest potential use of guggulipid in neuroinflammation associated conditions in CNS disorders. Copyright 2009 Elsevier Ireland Ltd. All rights reserved.

Multi-wavelength Radio Continuum Emission Studies of Dust-free Red Giants

NASA Technical Reports Server (NTRS)

O'Gorman, Eamon; Harper, Graham M.; Brown, Alexander; Dranke, Stephen; Richards, Anita M. S.

2013-01-01

Multi-wavelength centimeter continuum observations of non-dusty, non-pulsating K spectral-type red giants directly sample their chromospheres and wind acceleration zones. Such stars are feeble emitters at these wavelengths, however, and previous observations have provided only a small number of modest signal-to-noise measurements slowly accumulated over three decades. We present multi-wavelength Karl G. Jansky Very Large Array thermal continuum observations of the wind acceleration zones of two dust-free red giants, Arcturus (alpha Boo: K2 III) and Aldebaran (alpha Tau: K5 III). Importantly, most of our observations of each star were carried out over just a few days, so that we obtained a snapshot of the different stellar atmospheric layers sampled at different wavelengths, independent of any long-term variability. We report the first detections at several wavelengths for each star including a detection at 10 cm (3.0 GHz: S band) for both stars and a 20 cm (1.5 GHz: L band) detection for alpha Boo. This is the first time single (non-binary) luminosity class III red giants have been detected at these continuum wavelengths. Our long-wavelength data sample the outer layers of alpha Boo's atmosphere where its wind velocity is approaching (or possibly has reached) its terminal value and the ionization balance is becoming frozen-in. For alpha Tau, however, our long-wavelength data are still sampling its inner atmosphere, where the wind is still accelerating probably due to its lower mass-loss rate. We compare our data with published semi-empirical models based on ultraviolet data, and the marked deviations highlight the need for new atmospheric models to be developed. Spectral indices are used to discuss the possible properties of the stellar atmospheres, and we find evidence for a rapidly cooling wind in the case of alpha Boo. Finally, we develop a simple analytical wind model for alpha Boo based on our new long-wavelength flux measurements.

DIFFUSE Ly{alpha} EMITTING HALOS: A GENERIC PROPERTY OF HIGH-REDSHIFT STAR-FORMING GALAXIES

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

Steidel, Charles C.; Bogosavljevic, Milan; Shapley, Alice E.

2011-08-01

Using a sample of 92 UV continuum-selected, spectroscopically identified galaxies with (z) = 2.65, all of which have been imaged in the Ly{alpha} line with extremely deep narrow-band imaging, we examine galaxy Ly{alpha} emission profiles to very faint surface brightness limits. The galaxy sample is representative of spectroscopic samples of Lyman break galaxies (LBGs) at similar redshifts in terms of apparent magnitude, UV luminosity, inferred extinction, and star formation rate and was assembled without regard to Ly{alpha} emission properties. Approximately 45% (55%) of the galaxy spectra have Ly{alpha} appearing in net absorption (emission), with {approx_equal} 20% satisfying commonly used criteriamore » for the identification of 'Ly{alpha} emitters' (LAEs; W{sub 0}(Ly{alpha}) {>=} 20 A). We use extremely deep stacks of rest-UV continuum and continuum-subtracted Ly{alpha} images to show that all sub-samples exhibit diffuse Ly{alpha} emission to radii of at least 10'' ({approx}80 physical kpc). The characteristic exponential scale lengths for Ly{alpha} line emission exceed that of the {lambda}{sub 0} = 1220 A UV continuum light by factors of {approx}5-10. The surface brightness profiles of Ly{alpha} emission are strongly suppressed relative to the UV continuum light in the inner few kpc, by amounts that are tightly correlated with the galaxies' observed spectral morphology; however, all galaxy sub-subsamples, including that of galaxies for which Ly{alpha} appears in net absorption in the spectra, exhibit qualitatively similar diffuse Ly{alpha} emission halos. Accounting for the extended Ly{alpha} emission halos, which generally would not be detected in the slit spectra of individual objects or with typical narrow-band Ly{alpha} imaging, increases the total Ly{alpha} flux (and rest equivalent width W{sub 0}(Ly{alpha})) by an average factor of {approx}5, and by a much larger factor for the 80% of LBGs not classified as LAEs. We argue that most, if not all, of the observed Ly{alpha} emission in the diffuse halos originates in the galaxy H II regions but is scattered in our direction by H I gas in the galaxy's circum-galactic medium. The overall intensity of Ly{alpha} halos, but not the surface brightness distribution, is strongly correlated with the emission observed in the central {approx}1''-more luminous halos are observed for galaxies with stronger central Ly{alpha} emission. We show that whether or not a galaxy is classified as a giant 'Ly{alpha} blob' (LAB) depends sensitively on the Ly{alpha} surface brightness threshold reached by an observation. Accounting for diffuse Ly{alpha} halos, all LBGs would be LABs if surveys were sensitive to 10 times lower Ly{alpha} surface brightness thresholds; similarly, essentially all LBGs would qualify as LAEs.« less

Effect of heat treatment and enzymatic digestion on the B cell epitopes of cow's milk proteins.

PubMed

Morisawa, Y; Kitamura, A; Ujihara, T; Zushi, N; Kuzume, K; Shimanouchi, Y; Tamura, S; Wakiguchi, H; Saito, H; Matsumoto, K

2009-06-01

Processing milk leads to changes in clinical allergenicity. However, the mechanism by which heat treatment affects the allergenicity of milk proteins is not fully understood. We investigated the effect of heat treatment and enzymatic digestion on the allergenicity of B cell epitopes of milk proteins using a histamine release assay. Human basophils were passively sensitized using sera from 10 patients with allergies to cow's milk. All the patients experienced symptoms immediately after ingesting milk. The human basophils were obtained from umbilical cord blood mononuclear cells after culturing the mononuclear cells for 3-4 weeks in the presence of IL-3. After sensitization with 10% patient sera for 48 h, the cells were stimulated with untreated, heat-treated, or heat-treated and pepsin-and-trypsin-digested beta-lactoglobulin or alpha-casein for 1 h. The histamine concentrations in the supernatants were then measured by radioimmunoassay. Heat treatment alone did not alter the molecular weight of beta-lactoglobulin or alpha-casein. Heat treatment of beta-lactoglobulin significantly increased its susceptibility to enzymatic digestion in a time- and temperature-dependent manner and reduced its ability to induce histamine release from sensitized basophils. Similar findings were not observed for alpha-casein. The combination of heat treatment and enzymatic digestion reduced the abilities of both beta-lactoglobulin and alpha-casein to induce histamine release from passively sensitized basophils. Heat treatment reduced the allergenicity of beta-lactoglobulin by inducing conformational changes and by increasing its susceptibility to enzymatic digestion, both of which disrupted B cell epitopes, whereas heat treatment alone did not alter the allergenicity of alpha-casein.

Control of interface reactions in SIC/TI composites

NASA Technical Reports Server (NTRS)

Houska, C. R.; Rao, V.

1982-01-01

The reaction between a 0.5 to 1.0 Al film and a thick Ti substrate to form TiAl3 occurs very rapidly on heating to 635 C and causes the Al to be confined to the surface region. After heating to 900 C Ti3Al is formed with little release of Al into alpha Ti. Further annealing at 900 C eventually causes the Ti3Al phase to decompose and a substantial amount of Al is released into alpha Ti. The interdiffusion coefficient for Al in alpha Ti at 900 C increases by less than one order of magnitude as Al is varied from 0 to 20 at %. These data were obtained from the (101) X-ray diffraction intensity band using polycrystalline samples. Improvements in the analysis of X-ray diffraction data for the determination of composition profiles are discussed.

Prostaglandin release from in vitro guinea-pig gallbladder.

PubMed

Booker, M L; LaMorte, W W

1983-02-01

In order to study prostaglandin release from guinea pig gallbladder, full thickness tissue sections were incubated for one hour in Krebs solution. Extraction and two dimensional chromatography of incubation media obtained in the presence of radio-labelled arachidonic acid demonstrated the presence of PGE2, PGF2 alpha, 6-keto-PGF1 alpha and thromboxane B2. These results were supported by radioimmunoassay of incubations conducted in the absence of exogenous arachidonate and in the presence of varying concentrations of unlabelled exogenous arachidonate. The previously reported predominance of PGE2 was only seen at high concentrations of exogenous arachidonate.

/sup 45/Ca efflux for myometrial cells: comparison of the effects of prostaglandin F/sub 2/. cap alpha. (PGF/sub 2/), oxytocin (OT) and arachidonate (A)

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

Katona, G.; Molnar, M.; Toth, M.

1986-03-01

The aim of this study was to measure PGF/sub 2..cap alpha../-induced Ca/sup 2 +/ release from uterine cells and to compare this to the actions of OT and A. Smooth muscle cells isolated from the uterus (shell gland) of laying hens were cultured for 7 days in M199 plus 10% fetal calf serum. The cells were treated with digitonin (20..mu..M) and preloaded with /sup 45/Ca for 40 min. Addition of PGF/sub 2..cap alpha../ caused a biphasic /sup 45/Ca-efflux. There was a small but significant /sup 45/Ca-release within 30 sec (rapid phase) followed by a larger one within 7 min (slowmore » phase). In comparison, both OT and A stimulated /sup 45/Ca efflux during a single, slow phase. The maximal effect of A was observed at < 7 min, whereas that of OT was slower, peaking after 7 min. Mepacrin, an inhibitor of A release, attenuated the action of OT without having any effect on A promoted /sup 45/Ca-efflux. Indomethacin, an inhibitor of PG synthase, failed to suppress the Ca-releasing effect of A suggesting the A itself or a lipoxygenase product may have been responsible for the observed effects. Moreover, these results provide suggestive evidence that A release is an important step in the action of various uterotonic agents converging on the mobilization of intracellular Ca.« less

Background Characterization for Thermal Ion Release Experiments with 224Ra

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

Kwong, H.; /Stanford U., Phys. Dept.; Rowson, P.

The Enriched Xenon Observatory for neutrinoless double beta decay uses {sup 136}Ba identification as a means for verifying the decay's occurrence in {sup 136}Xe. A current challenge is the release of Ba ions from the Ba extraction probe, and one possible solution is to heat the probe to high temperatures to release the ions. The investigation of this method requires a characterization of the alpha decay background in our test apparatus, which uses a {sup 228}Th source that produces {sup 224}Ra daughters, the ionization energies of which are similar to those of Ba. For this purpose, we ran a backgroundmore » count with our apparatus maintained at a vacuum, and then three counts with the apparatus filled with Xe gas. We were able to match up our alpha spectrum in vacuum with the known decay scheme of {sup 228}Th, while the spectrum in xenon gas had too many unresolved ambiguities for an accurate characterization. We also found that the alpha decays occurred at a near-zero rate both in vacuum and in xenon gas, which indicates that the rate was determined by {sup 228}Th decays. With these background measurements, we can in the future make a more accurate measurement of the temperature dependency of the ratio of ions to neutral atoms released from the hot surface of the probe, which may lead to a successful method of Ba ion release.« less

In vivo release of calcitonin gene-related peptide-like material from the cervicotrigeminal area in the rat. Effects of electrical and noxious stimulations of the muzzle.

PubMed

Pohl, M; Collin, E; Bourgoin, S; Clot, A M; Hamon, M; Cesselin, F; Le Bars, D

1992-10-01

The continuous perfusion with an artificial cerebrospinal fluid of the cervicotrigeminal area of the spinal cord in halothane-anaesthetized rats allowed the collection of calcitonin gene-related peptide-like material with the same immunological and chromatographic characteristics as authentic rat alpha-calcitonin gene-related peptide. The spinal release of calcitonin gene-related peptide-like material could be significantly increased by the local application of 60 mM K+ (approximately +100%), high-intensity percutaneous electrical stimulation (approximately +200%) and noxious heat (by immersion in water at 52 degrees C; approximately +150%) applied to the muzzle. By contrast, noxious mechanical (pinches) and chemical (subcutaneous formalin injection) stimulations and deep cooling (by immersion in water at 0 degrees C) of the muzzle did not alter the spinal release of calcitonin gene-related peptide-like material. In addition, low-intensity electrical stimulation, recruiting only the A alpha/beta primary afferent fibres, significantly reduced (approximately -30%) the release of calcitonin gene-related peptide-like material from the cervicotrigeminal area. These data suggest that among the various types of natural noxious stimuli, noxious heat may selectively excite calcitonin gene-related peptide-containing A delta and C primary afferent fibres projecting within the dorsal horn of the spinal cord, and that activation of A alpha/beta fibres reduces spontaneous calcitonin gene-related peptide-like material release possibly through an inhibitory presynaptic control of calcitonin gene-related peptide-containing A delta/C fibres.

Preliminary Work Toward a Transuranic Activity Estimation Method for Rapid Discrimination of Anthropogenic from Transuranic Activity in Alpha Air Samples

DOE PAGES

Cope, S. Joseph; Hayes, Robert B.

2018-03-01

Radon ( 222Rn) and thoron ( 220Rn) progeny (primarily bismuth and polonium) are known interferents when rapid evaluation of transuranic content on air filters is of interest. These complexities stem from the overlapping energies of the progeny alpha particles onto the transuranic region of interest (3–5.5 MeV) where naturally-occurring alpha emitters can overwhelm the spectra. Due to the immediacy of the alpha counting methods employed, coupled with the half-life of thoron progeny dominated by 212Pb (t 1/2=10.6 h), a conservative transuranic activity estimate with rigorous uncertainty is being sought. A successful transuranic activity estimation method will incorporate any thoron progenymore » present on the filter providing 95% confidence decision levels in which a filter may be evaluated for emergency response applications. Twenty-three pairs of samples of various duration having no transuranic content were taken over a 2-mo period. The resulting filters were counted in a time series before non-linear least squares decay curve fitting was applied to the decay profile. For the samples considered, a transuranic activity estima-tor decision level was determined at 0.2 Bq for the given geographic location and months analyzed. In conclusion, validation of this method for other seasonal and geographic regions could provide enhanced emergency response capability when the presence of transuranic activity is suspected.« less

Preliminary Work Toward a Transuranic Activity Estimation Method for Rapid Discrimination of Anthropogenic from Transuranic Activity in Alpha Air Samples

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

Cope, S. Joseph; Hayes, Robert B.

Radon ( 222Rn) and thoron ( 220Rn) progeny (primarily bismuth and polonium) are known interferents when rapid evaluation of transuranic content on air filters is of interest. These complexities stem from the overlapping energies of the progeny alpha particles onto the transuranic region of interest (3–5.5 MeV) where naturally-occurring alpha emitters can overwhelm the spectra. Due to the immediacy of the alpha counting methods employed, coupled with the half-life of thoron progeny dominated by 212Pb (t 1/2=10.6 h), a conservative transuranic activity estimate with rigorous uncertainty is being sought. A successful transuranic activity estimation method will incorporate any thoron progenymore » present on the filter providing 95% confidence decision levels in which a filter may be evaluated for emergency response applications. Twenty-three pairs of samples of various duration having no transuranic content were taken over a 2-mo period. The resulting filters were counted in a time series before non-linear least squares decay curve fitting was applied to the decay profile. For the samples considered, a transuranic activity estima-tor decision level was determined at 0.2 Bq for the given geographic location and months analyzed. In conclusion, validation of this method for other seasonal and geographic regions could provide enhanced emergency response capability when the presence of transuranic activity is suspected.« less

Alpha-particle-induced cancer in humans

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

Mays, C.W.

Updated information is given on alpha-particle-induced cancer in persons internally exposed to 222Rn progeny, Thorotrast, long-lived 226Ra and 228Ra, and short-lived 224Ra. The lung cancer risk to persons breathing 222Rn progeny in the indoor air of offices, schools, and homes is of increasing concern. About half of the recent deaths among the German Thorotrast patients have been from liver cancer. Animal studies indicate that the liver cancer risk from Thorotrast is mainly from its radioactivity and that the risk coefficient for the Thorotrast patients can be used provisionally for other alpha emitters in the human liver. Six skeletal cancers havemore » occurred in persons with average skeletal doses between 0.85 and 11.8 Gy from 226Ra and 228Ra. In the low-dose German 224Ra patients, two skeletal sarcomas have occurred at about 0.7 Gy compared to about six cases predicted by results from 224Ra patients at higher doses. The minimal appearance time for radiation-induced bone sarcomas in humans is about 4 y. Following brief irradiation, the vast majority of induced bone sarcomas are expressed by about 30 y. Recent evidence against the practical threshold hypothesis is given. With the downward revision of neutron doses to the atomic-bomb survivors, the follow-up of persons exposed to alpha particles may be the best opportunity to evaluate directly the effects of high LET radiation on humans. 90 references.« less

Apparatus and method for quantitative assay of generic transuranic wastes from nuclear reactors

DOEpatents

Caldwell, J.T.; Kunz, W.E.; Atencio, J.D.

1982-03-31

A combination of passive and active neutron measurements which yields quantitative information about the isotopic composition of transuranic wastes from nuclear power or weapons material manufacture reactors is described. From the measurement of prompt and delayed neutron emission and the incidence of two coincidentally emitted neutrons from induced fission of fissile material in the sample, one can quantify /sup 233/U, /sup 235/U and /sup 239/Pu isotopes in waste samples. Passive coincidence counting, including neutron multiplicity measurement and determination of the overall passive neutron flux additionally enables the separate quantitative evaluation of spontaneous fission isotopes such as /sup 240/Pu, /sup 244/Cm and /sup 252/Cf, and the spontaneous alpha particle emitter /sup 241/Am. These seven isotopes are the most important constituents of wastes from nuclear power reactors and once the mass of each isotope present is determined by the apparatus and method of the instant invention, the overall alpha particle activity can be determined to better than 1 nCi/g from known radioactivity data. Therefore, in addition to the quantitative analysis of the waste sample useful for later reclamation purposes, the alpha particle activity can be determined to decide whether permanent low-level burial is appropriate for the waste sample.

Apparatus and method for quantitative assay of generic transuranic wastes from nuclear reactors

DOEpatents

Caldwell, John T.; Kunz, Walter E.; Atencio, James D.

1984-01-01

A combination of passive and active neutron measurements which yields quantitative information about the isotopic composition of transuranic wastes from nuclear power or weapons material manufacture reactors is described. From the measurement of prompt and delayed neutron emission and the incidence of two coincidentally emitted neutrons from induced fission of fissile material in the sample, one can quantify .sup.233 U, .sup.235 U and .sup.239 Pu isotopes in waste samples. Passive coincidence counting, including neutron multiplicity measurement and determination of the overall passive neutron flux additionally enables the separate quantitative evaluation of spontaneous fission isotopes such as .sup.240 Pu, .sup.244 Cm and .sup.252 Cf, and the spontaneous alpha particle emitter .sup.241 Am. These seven isotopes are the most important constituents of wastes from nuclear power reactors and once the mass of each isotope present is determined by the apparatus and method of the instant invention, the overall alpha particle activity can be determined to better than 1 nCi/g from known radioactivity data. Therefore, in addition to the quantitative analysis of the waste sample useful for later reclamation purposes, the alpha particle activity can be determined to decide whether "permanent" low-level burial is appropriate for the waste sample.

Linear Collider Test Facility: Twiss Parameter Analysis at the IP/Post-IP Location of the ATF2 Beam Line

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

Bolzon, Benoit; /Annecy, LAPP; Jeremie, Andrea

2012-07-02

At the first stage of the ATF2 beam tuning, vertical beam size is usually bigger than 3 {micro}m at the IP. Beam waist measurements using wire scanners and a laser wire are usually performed to check the initial matching of the beam through to the IP. These measurements are described in this paper for the optics currently used ({beta}{sub x} = 4cm and {beta}{sub y} = 1mm). Software implemented in the control room to automate these measurements with integrated analysis is also described. Measurements showed that {beta} functions and emittances were within errors of measurements when no rematching and couplingmore » corrections were done. However, it was observed that the waist in the horizontal (X) and vertical (Y) plane was abnormally shifted and simulations were performed to try to understand these shifts. They also showed that multiknobs are needed in the current optics to correct simultaneously {alpha}{sub x}, {alpha}{sub y} and the horizontal dispersion (D{sub x}). Such multiknobs were found and their linearity and orthogonality were successfully checked using MAD optics code. The software for these multiknobs was implemented in the control room and waist scan measurements using the {alpha}{sub y} knob were successfully performed.« less

Approaching reionization from two directions: high-redshift Lyman-alpha emitters and local analogs

NASA Astrophysics Data System (ADS)

Bagley, Micaela

2018-01-01

The dark ages that followed the recombination of the universe ended with the appearance of metal-free stars and the subsequent formation of numerous low-mass, metal-poor galaxies. The collective ionizing background from these newly-forming galaxies is thought to be responsible for the reionization of the diffuse hydrogen in the intergalactic medium between redshifts 10 and 6.5. The progression of the reionization history depends on the nature of these first sources -- their number densities, luminosities, clustering, and production rates of ionizing photons -- which is currently the subject of considerable observational and theoretical efforts.I will present results of a two-pronged approach to studying the Epoch of Reionization: a systematic search for Lyman-alpha emitting galaxies at redshifts greater than 6, and an analysis of high S/N spectra of a sample of local galaxies that are potential analogs to those responsible for the reionization. Selected for their large [OIII]/[OII] ratios and high H-alpha equivalent widths, the local galaxies have very low masses and are consistent with photoionization by stars with effective temperatures of 10^5 K. Both the emission lines and continua of the spectra are spatially extended, allowing for an analysis of galaxy properties such as gas temperature, elemental abundance, and ionizing power at different radii.

Physiological and anatomical studies of the development of the sympathetic innervation to rat iris arterioles.

PubMed

Sandow; Hill

1999-09-24

The development of the sympathetic innervation to rat irideal arterioles has been investigated using histochemical and in vitro pharmacological and electrophysiological methods. A plexus of fibres and varicosities appeared over the surface of the vessels after the first postnatal week and increased to reach a maximum density during the fourth postnatal week. Transmural nerve stimulation produced small, consistent contractions that were first recorded in arterioles of 7-day old rats. Contractions became larger and faster, reaching the adult form during the fourth postnatal week. Contractions became more sensitive to the alpha1-adrenoceptor antagonists, prazosin and naftopidil, and less sensitive to the alpha1A/D antagonist, WB4101 and alpha2 antagonist, yohimbine, during development. At both 10 and 21 days, contractile responses resulted from the release of intracellular calcium as they were abolished by caffeine (10(-3) M), thapsigargin (2 x 10(-6) M) and cyclopiazonic acid (3 x 10(-6) M), but not by nifedipine (10(-6) M). Intracellular recordings showed that nerve stimulation produced large, slow depolarizations at all ages tested. Time to peak potential decreased during development, while the amplitude of the depolarizations did not vary significantly. Results suggest that, throughout development, sympathetic nerves cause constriction of iris arterioles due to the release of noradrenaline and activation of alpha-adrenoceptors on the smooth muscle cells. Early responses involved both alpha1- and alpha2-adrenoceptors, while later responses were due to alpha1-adrenoceptors only. Irrespective of these changes in adrenoceptor subtypes, smooth muscle contraction resulted from the mobilization of intracellular calcium suggesting that both alpha1- and alpha2-adrenoceptors were coupled to pathways which accessed this source of calcium.

Astatine-211 conjugated to an anti-CD20 monoclonal antibody eradicates disseminated B-cell lymphoma in a mouse model

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

Green, Damian J.; Shadman, Mazyar; Jones, Jon C.

Alpha emitting radionuclides release a large amount of energy within a few cell diameters and may be particularly effective for radioimmunotherapy targeting minimal residual disease (MRD) conditions in which micrometastatic disease satellites are broadly distributed. To evaluate this hypothesis, 211At conjugated 1F5 mAb (anti-CD20) was studied in both bulky lymphoma tumor xenograft and MRD animal models. Superior treatment responses to 211At conjugated 1F5 mAb were evident in the MRD setting. Lymphoma xenograft tumor bearing animals treated with doses of up to 48µCi of anti-CD20 211At-decaborate [211At-B10-1F5] experienced modest responses (0% cures but 2-3-fold prolongation of survival compared to negative controls).more » In contrast, 70% of animals in the MRD lymphoma model demonstrated complete eradication of disease when treated with 211At-B10-1F5 at a radiation dose that was less than one-third (15 µCi) of the highest dose given to xenograft animals. Tumor progression among untreated control animals in both models was uniformly lethal. After 130 days, no significant renal or hepatic toxicity is observed in the cured animals receiving 15 µCi of 211At-B10-1F5. These findings suggest that in a MRD lymphoma model, where isolated cells and tumor microclusters prevail, α-emitters may be uniquely efficacious.« less

Investigation of tenuous plasma environment using Active Spacecraft Potential Control (ASPOC) on Magnetospheric Multiscale (MMS) Mission

NASA Astrophysics Data System (ADS)

Nakamura, Rumi; Jeszenszky, Harald; Torkar, Klaus; Andriopoulou, Maria; Fremuth, Gerhard; Taijmar, Martin; Scharlemann, Carsten; Svenes, Knut; Escoubet, Philippe; Prattes, Gustav; Laky, Gunter; Giner, Franz; Hoelzl, Bernhard

2015-04-01

The NASA's Magnetospheric Multiscale (MMS) Mission is planned to be launched on March 12, 2015. The scientific objectives of the MMS mission are to explore and understand the fundamental plasma physics processes of magnetic reconnection, particle acceleration and turbulence in the Earth's magnetosphere. The region of scientific interest of MMS is in a tenuous plasma environment where the positive spacecraft potential reaches an equilibrium at several tens of Volts. An Active Spacecraft Potential Control (ASPOC) instrument neutralizes the spacecraft potential by releasing positive charge produced by indium ion emitters. ASPOC thereby reduces the potential in order to improve the electric field and low-energy particle measurement. The method has been successfully applied on other spacecraft such as Cluster and Double Star. Two ASPOC units are present on each of the MMS spacecraft. Each unit contains four ion emitters, whereby one emitter per instrument is operated at a time. ASPOC for MMS includes new developments in the design of the emitters and the electronics enabling lower spacecraft potentials, higher reliability, and a more uniform potential structure in the spacecraft's sheath compared to previous missions. Model calculations confirm the findings from previous applications that the plasma measurements will not be affected by the beam's space charge. A perfectly stable spacecraft potential precludes the utilization of the spacecraft as a plasma probe, which is a conventional technique used to estimate ambient plasma density from the spacecraft potential. The small residual variations of the potential controlled by ASPOC, however, still allow to determine ambient plasma density by comparing two closely separated spacecraft and thereby reconstructing the uncontrolled potential variation from the controlled potential. Regular intercalibration of controlled and uncontrolled potentials is expected to increase the reliability of this new method.

Intracellular disposal of incompletely folded human alpha1-antitrypsin involves release from calnexin and post-translational trimming of asparagine-linked oligosaccharides.

PubMed

Liu, Y; Choudhury, P; Cabral, C M; Sifers, R N

1997-03-21

Protection of lung elastin fibers from proteolytic destruction is compromised by inefficient secretion of incompletely folded allelic variants of human alpha1-antitrypsin from hepatocytes. Pulse-chase radiolabeling with [35S]methionine and sucrose gradient sedimentation and coimmunoprecipitation techniques were employed to investigate quality control of human alpha1-antitrypsin secretion from stably transfected mouse hepatoma cells. The secretion-incompetent variant null(Hong Kong) (Sifers, R. N., Brashears-Macatee, S., Kidd, V. J., Muensch, H., and Woo, S. L. C. (1988) J. Biol. Chem. 263, 7330-7335) cannot fold into a functional conformation and was quantitatively associated with the molecular chaperone calnexin following biosynthesis. Assembly with calnexin required cotranslational trimming of glucose from asparagine-linked oligosaccharides. Intracellular disposal of pulse-radiolabeled molecules coincided with their release from calnexin. Released monomers and intracellular disposal were nonexistent in cells chased with cycloheximide, an inhibitor of protein synthesis. Post-translational trimming of asparagine-linked oligosaccharides and intracellular disposal were abrogated by 1-deoxymannojirimycin, an inhibitor of alpha-mannosidase activity, without affecting the monomer population. The data are consistent with a recently proposed quality control model (Hammond, C., Braakman, I., and Helenius, A. (1994) Proc. Natl. Acad. Sci. U. S. A. 91, 913-917) in which intracellular disposal requires dissociation from calnexin and post-translational trimming of mannose from asparagine-linked oligosaccharides.

EEG alpha asymmetry as a gender-specific predictor of outcome to acute treatment with different antidepressant medications in the randomized iSPOT-D study.

PubMed

Arns, Martijn; Bruder, Gerard; Hegerl, Ulrich; Spooner, Chris; Palmer, Donna M; Etkin, Amit; Fallahpour, Kamran; Gatt, Justine M; Hirshberg, Laurence; Gordon, Evian

2016-01-01

To determine whether EEG occipital alpha and frontal alpha asymmetry (FAA) distinguishes outpatients with major depression (MDD) from controls, predicts antidepressant treatment outcome, and to explore the role of gender. In the international Study to Predict Optimized Treatment in Depression (iSPOT-D), a multi-center, randomized, prospective open-label trial, 1008 MDD participants were randomized to escitalopram, sertraline or venlafaxine-extended release. The study also recruited 336 healthy controls. Treatment response was established after eight weeks and resting EEG was measured at baseline (two minutes eyes open and eyes closed). No differences in EEG alpha for occipital and frontal cortex, or for FAA, were found in MDD participants compared to controls. Alpha in the occipital and frontal cortex was not associated with treatment outcome. However, a gender and drug-class interaction effect was found for FAA. Relatively greater right frontal alpha (less cortical activity) in women only was associated with a favorable response to the Selective Serotonin Reuptake Inhibitors escitalopram and sertraline. No such effect was found for venlafaxine-extended release. FAA does not differentiate between MDD and controls, but is associated with antidepressant treatment response and remission in a gender and drug-class specific manner. Future studies investigating EEG alpha measures in depression should a-priori stratify by gender. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Hsp105 family proteins suppress staurosporine-induced apoptosis by inhibiting the translocation of Bax to mitochondria in HeLa cells

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

Yamagishi, Nobuyuki; Ishihara, Keiichi; Saito, Youhei

2006-10-15

Hsp105 (Hsp105{alpha} and Hsp105{beta}), major heat shock proteins in mammalian cells, belong to a subgroup of the HSP70 family, HSP105/110. Previously, we have shown that Hsp105{alpha} has completely different effects on stress-induced apoptosis depending on cell type. However, the molecular mechanisms by which Hsp105{alpha} regulates stress-induced apoptosis are not fully understood. Here, we established HeLa cells that overexpress either Hsp105{alpha} or Hsp105{beta} by removing doxycycline and examined how Hsp105 modifies staurosporine (STS)-induced apoptosis in HeLa cells. Apoptotic features such as the externalization of phosphatidylserine on the plasma membrane and nuclear morphological changes were induced by the treatment with STS, andmore » the STS-induced apoptosis was suppressed by overexpression of Hsp105{alpha} or Hsp105{beta}. In addition, we found that overexpression of Hsp105{alpha} or Hsp105{beta} suppressed the activation of caspase-3 and caspase-9 by preventing the release of cytochrome c from mitochondria. Furthermore, the translocation of Bax to mitochondria, which results in the release of cytochrome c from the mitochondria, was also suppressed by the overexpression of Hsp105{alpha} or Hsp105{beta}. Thus, it is suggested that Hsp105 suppresses the stress-induced apoptosis at its initial step, the translocation of Bax to mitochondria in HeLa cells.« less

Relative biological effectiveness (RBE) of alpha radiation in cultured porcine aortic endothelial cells.

PubMed

Thomas, Patricia; Tracy, Bliss; Ping, Tilly; Baweja, Anar; Wickstrom, Mark; Sidhu, Narinder; Hiebert, Linda

2007-03-01

Northern peoples can receive elevated radiation doses (1- 10 mSv/y) from transfer of polonium-210 (210Po) through the lichen-caribou-human food chain. Ingested 210Po is primarily blood-borne and thus many of its short range alpha particles irradiate the endothelial cells lining the blood vessels. The relative biological effectiveness (RBE) of alpha particles vs. x-rays was examined in porcine aortic endothelial cells as a surrogate for understanding what might happen to human endothelial cells in northern populations consuming traditional foods. Cultured porcine aortic endothelial cells were exposed to x-ray and 210Po alpha particle radiation. Alpha irradiation was applied to the cell cultures internally via the culture medium and externally, using thin-bottomed culture dishes. The results given here are based on the external irradiation method, which was found to be more reliable. Dose-response curves were compared for four lethal endpoints (cell viability, live cell fraction, release of lactate dehydrogenase [LDH] and clonogenic survival) to determine the relative biological effectiveness (RBE) of alpha radiation. The alpha RBE for porcine cells varied from 1.6-21, depending on the endpoint: 21.2+/-4.5 for cell viability, 12.9+/-2.7 for decrease in live cell number, 5.3+/-0.4 for LDH release to the medium but only 1.6 +/-0.1 for clonogenic survival. The low RBE of 1.6 was due to x-ray hypersensitivity of endothelial cells at low doses.

Methane emission estimates using chamber and tracer release experiments for a municipal waste water treatment plant

NASA Astrophysics Data System (ADS)

Yver Kwok, C. E.; Müller, D.; Caldow, C.; Lebègue, B.; Mønster, J. G.; Rella, C. W.; Scheutz, C.; Schmidt, M.; Ramonet, M.; Warneke, T.; Broquet, G.; Ciais, P.

2015-07-01

This study presents two methods for estimating methane emissions from a waste water treatment plant (WWTP) along with results from a measurement campaign at a WWTP in Valence, France. These methods, chamber measurements and tracer release, rely on Fourier transform infrared spectroscopy and cavity ring-down spectroscopy instruments. We show that the tracer release method is suitable for quantifying facility- and some process-scale emissions, while the chamber measurements provide insight into individual process emissions. Uncertainties for the two methods are described and discussed. Applying the methods to CH4 emissions of the WWTP, we confirm that the open basins are not a major source of CH4 on the WWTP (about 10 % of the total emissions), but that the pretreatment and sludge treatment are the main emitters. Overall, the waste water treatment plant is representative of an average French WWTP.

Prostaglandin mediates endotoxaemia-induced hypophagia by activation of pro-opiomelanocortin and corticotrophin-releasing factor neurons in rats.

PubMed

Rorato, Rodrigo; Menezes, Aline Motta; Giusti-Paiva, Alexandre; de Castro, Margaret; Antunes-Rodrigues, José; Elias, Lucila Leico Kagohara

2009-03-01

Corticotrophin-releasing factor (CRF) and alpha-melanocyte-stimulating hormone (alpha-MSH), both of which are synthesized by hypothalamic neurons, play an essential role in the control of energy homeostasis. Neuroendocrine and behavioural responses induced by lipopolyssacharide (LPS) have been shown to involve prostaglandin-mediated pathways. This study investigated the effects of prostaglandin on CRF and alpha-MSH neuronal activities in LPS-induced anorexia. Male Wistar rats were pretreated with indomethacin (10 mg kg(-1); i.p.) or vehicle; 15 min later they received LPS (500 microg kg(-1); i.p.) or saline injection. Food intake, hormone responses and Fos-CRF and Fos-alpha-MSH immunoreactivity in the paraventricular and arcuate nuclei, respectively, were evaluated. In comparison with saline treatment, LPS administration induced lower food intake and increased plasma ACTH and corticosterone levels, as well as an increase in Fos-CRF and Fos-alpha-MSH double-labelled neurons in vehicle-pretreated rats. In contrast, indomethacin treatment partly reversed the hypophagic effect, blunted the hormonal increase and blocked the Fos-CRF and Fos-alpha-MSH hypothalamic double labelling increase in response to the LPS stimulus. These data demonstrate that the activation of pro-opiomelanocortin and CRF hypothalamic neurons following LPS administration is at least partly mediated by the prostaglandin pathway and is likely to be involved in the modulation of feeding behaviour during endotoxaemia.

Release of tumor necrosis factor alpha and interleukin 6 during antibiotic killing of Escherichia coli in whole blood: influence of antibiotic class, antibiotic concentration, and presence of septic serum.

PubMed

Prins, J M; Kuijper, E J; Mevissen, M L; Speelman, P; van Deventer, S J

1995-06-01

The concentration and accessibility of endotoxin can increase following antibiotic killing of gram-negative bacteria. There are indications that antibiotics may differ in this respect. We measured endotoxin levels in RPMI 1640 and tumor necrosis factor alpha (TNF-alpha) and interleukin-6 production in whole blood ex vivo after exposure of log-phase Escherichia coli to antibiotics belonging to different classes, in a final concentration of 0.5, 5, or 50 times the MIC. After 4 h of incubation at 50 times the MIC, ceftazidime and ciprofloxacin treatment resulted in levels of endotoxin, TNF-alpha, and interleukin-6 significantly higher than those of imipenem and gentamicin (P < 0.001). Similar differences in cytokine induction were measured after 8 h of incubation. At 0.5 times the MIC, the differences between the antibiotics in measured endotoxin and cytokine levels were small, with levels comparable to the levels in untreated cultures. Polymyxin B and, to a lesser degree, recombinant bactericidal/permeability-increasing protein 21 (rBPI-21) were found to be potent inhibitors of TNF-alpha release, supporting the concept that the differences between the antibiotics in cytokine production were indeed due to differences in amounts of biologically active endotoxin. The presence of serum from patients suffering from untreated sepsis decreased TNF-alpha production significantly, in a concentration-dependent manner.

Isolation and Characterization of Escherichia coli tolC Mutants Defective in Secreting Enzymatically Active Alpha-Hemolysin

PubMed Central

Vakharia, Hema; German, Greg J.; Misra, Rajeev

2001-01-01

This study describes the isolation and characterization of a unique class of TolC mutants that, under steady-state growth conditions, secreted normal levels of largely inactive alpha-hemolysin. Unlike the reduced activity in the culture supernatants, the cell-associated hemolytic activity in these mutants was identical to that in the parental strain, thus reflecting a normal intracellular toxin activation event. Treatment of the secreted toxin with guanidine hydrochloride significantly restored cytolytic activity, suggesting that the diminished activity may have been due to the aggregation or misfolding of the toxin molecules. Consistent with this notion, sedimentation and filtration analyses showed that alpha-hemolysin secreted from the mutant strain has a mass greater than that secreted from the parental strain. Experiments designed to monitor the time course of alpha-hemolysin release showed delayed appearance of toxin in the culture supernatant of the mutant strain, thus indicating a possible defect in alpha-hemolysin translocation or release. Eight different TolC substitutions displaying this toxin secretion defect were scattered throughout the protein, of which six localized in the periplasmically exposed α-helical domain, while the remaining two mapped within the outer membrane-embedded β-barrel domain of TolC. A plausible model for the secretion of inactive alpha-hemolysin in these TolC mutants is discussed in the context of the recently determined three-dimensional structure of TolC. PMID:11698380

A novel immune-to-CNS communication pathway: cells of the meninges surrounding the spinal cord CSF space produce proinflammatory cytokines in response to an inflammatory stimulus.

PubMed

Wieseler-Frank, Julie; Jekich, Brian M; Mahoney, John H; Bland, Sondra T; Maier, Steven F; Watkins, Linda R

2007-07-01

Pain is enhanced in response to elevations of proinflammatory cytokines in spinal cerebrospinal fluid (CSF), following either intrathecal injection of these cytokines or intrathecal immune challenge with HIV-1 gp120 that induces cytokine release. Spinal cord glia have been assumed to be the source of endogenous proinflammatory cytokines that enhance pain. However, assuming that spinal cord glia are the sole source of CSF cytokines may be an underestimate, as the cellular composition of the meninges surrounding the spinal cord CSF space includes several cell types known to produce proinflammatory cytokines. The present experiments provide the first investigation of the immunocompetent nature of the spinal cord meninges. Here, we explore whether rat meninges are responsive to intrathecal gp120. These studies demonstrate that: (a) intrathecal gp120 upregulates meningeal gene expression of proinflammatory signals, including tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), interleukin 6 (IL-6), and inducible nitric oxide synthase (iNOS), and (b) intrathecal gp120 induces meningeal release of TNF-alpha, IL-1beta, and IL-6. In addition, stimulation of isolated meninges in vitro with gp120 induced the release of TNF-alpha and IL-1beta, indicating that the resident cells of the meninges are able to respond without immune cell recruitment. Taken together, these data document that the meninges are responsive to immunogenic stimuli in the CSF and that the meninges may be a source of immune products detected in CSF. The ability of the meninges to release to proinflammatory signals suggests a potential role in the modulation of pain.

Effects of cryopreservation and hypothermic storage on cell viability and enzyme activity in recombinant encapsulated cells overexpressing alpha-L-iduronidase.

PubMed

Mayer, Fabiana Quoos; Baldo, Guilherme; de Carvalho, Talita Giacomet; Lagranha, Valeska Lizzi; Giugliani, Roberto; Matte, Ursula

2010-05-01

Here, we show the effects of cryopreservation and hypothermic storage upon cell viability and enzyme release in alginate beads containing baby hamster kidney cells overexpressing alpha-L-iduronidase (IDUA), the enzyme deficient in mucopolysaccharidosis type I. In addition, we compared two different concentrations of alginate gel (1% and 1.5%) in respect to enzyme release from the beads and their shape and integrity. Our results indicate that in both alginate concentrations, the enzyme is released in lower amounts compared with nonencapsulated cells. Alginate 1% beads presented increased levels of IDUA release, although this group presented more deformities when compared with alginate 1.5% beads. Importantly, both encapsulated groups presented higher cell viability after long cryopreservation period and hypothermic storage. In addition, alginate 1.5% beads presented higher enzyme release after freezing protocols. Taken together, our findings suggest a benefic effect of alginate upon cell viability and functionality. These results may have important application for treatment of both genetic and nongenetic diseases using microencapsulation-based artificial organs.

Quantitative comparisons of cancer induction in humans by internally deposited radionuclides and external radiation.

PubMed

Harrison, J D; Muirhead, C R

2003-01-01

To compare quantitative estimates of lifetime cancer risk in humans for exposures to internally deposited radionuclides and external radiation. To assess the possibility that risks from radionuclide exposures may be underestimated. Risk estimates following internal exposures can be made for a small number of alpha-particle-emitting nuclides. (1) Lung cancer in underground miners exposed by inhalation to radon-222 gas and its short-lived progeny. Studies of residential (222)Rn exposure are generally consistent with predictions from the miner studies. (2) Liver cancer and leukaemia in patients given intravascular injections of Thorotrast, a thorium-232 oxide preparation that concentrates in liver, spleen and bone marrow. (3) Bone cancer in patients given injections of radium-224, and in workers exposed occupationally to (226)Ra and (228)Ra, mainly by ingestion. (4) Lung cancer in Mayak workers exposed to plutonium-239, mainly by inhalation. Liver and bone cancers were also seen, but the dosimetry is not yet sufficiently good enough to provide quantitative estimates of risks. Comparisons can be made between risk estimates for radiation-induced cancer derived for radionuclide exposure and those derived for the A-bomb survivors, exposed mainly to low-LET (linear energy transfer) external radiation. Data from animal studies, using dogs and rodents, allow comparisons of cancer induction by a range of alpha- and beta-/gamma-emitting radionuclides. They provide information on relative biological effectiveness (RBE), dose-response relationships, dose-rate effects and the location of target cells for different malignancies. For lung and liver cancer, the estimated values of risk per Sv for internal exposure, assuming an RBE for alpha-particles of 20, are reasonably consistent with estimates for external exposure to low-LET radiation. This also applies to bone cancer when risk is calculated on the basis of average bone dose, but consideration of dose to target cells on bone surfaces suggests a low RBE for alpha-particles. Similarly, for leukaemia, the comparison of risks from alpha-irradiation ((232)Th and progeny) and external radiation suggest a low alpha RBE; this conclusion is supported by animal data. Risk estimates for internal exposure are dependent on the assumptions made in calculating dose. Account is taken of the distribution of radionuclides within tissues and the distribution of target cells for cancer induction. For the lungs and liver, the available human and animal data provide support for current assumptions. However, for bone cancer and leukaemia, it may be that changes are required. Bone cancer risk may be best assessed by calculating dose to a 50 micro m layer of marrow adjacent to endosteal (inner) bone surfaces rather than to a single 10 micro m cell layer as currently assumed. Target cells for leukaemia may be concentrated towards the centre of marrow cavities so that the risk of leukaemia from bone-seeking radionuclides, particularly alpha emitters, may be overestimated by the current assumption of uniform distribution of target cells throughout red bone marrow. The lifetime risk estimates considered here for exposure to internally deposited radionuclides and to external radiation are subject to uncertainties, arising from the dosimetric assumptions made, from the quality of cancer incidence and mortality data and from aspects of risk modelling; including variations in baseline rates between populations for some cancer types. Bearing in mind such uncertainties, comparisons of risk estimates for internal emitters and external radiation show good agreement for lung and liver cancers. For leukaemia, the available data suggest that the assumption of an alpha-particle RBE of 20 can result in overestimates of risk. For bone cancer, it also appears that current assumptions will overestimate risks from alpha-particle-emitting nuclides, particularly at low doses.

Characterization of the expression, localization, and secretion of PANDER in alpha-cells.

PubMed

Carnegie, Jason R; Robert-Cooperman, Claudia E; Wu, Jianmei; Young, Robert A; Wolf, Bryan A; Burkhardt, Brant R

2010-08-30

The novel islet-specific protein PANcreatic DERived Factor (PANDER; FAM3B) has been extensively characterized with respect to the beta-cell, and these studies suggest a potential function for PANDER in the regulation of glucose homeostasis. Little is known regarding PANDER in pancreatic -cells, which are critically involved in maintaining euglycemia. Here we present the first report elucidating the expression and regulation of PANDER within the alpha-cell. Pander mRNA and protein are detected in alpha-cells, with primary localization to a glucagon-negative granular cytosolic compartment. PANDER secretion from alpha-cells is nutritionally and hormonally regulated by l-arginine and insulin, demonstrating similarities and differences with glucagon. Signaling via the insulin receptor (IR) through the PI3K and Akt/PKB node is required for insulin-stimulated PANDER release. The separate localization of PANDER and glucagon is consistent with their differential regulation, and the effect of insulin suggests a paracrine/endocrine effect on PANDER release. This provides further insight into the potential glucose-regulatory role of PANDER. Copyright (c) 2010 Elsevier Ireland Ltd. All rights reserved.

Profiles of alpha-melanocyte-stimulating hormone in the Japanese flounder as revealed by a newly developed time-resolved fluoroimmunoassay and immunohistochemistry.

PubMed

Amiya, Noriko; Amano, Masafumi; Takahashi, Akiyoshi; Yamanome, Takeshi; Yamamori, Kunio

2007-03-01

Profiles of alpha-melanocyte-stimulating hormone (alpha-MSH) in the Japanese flounder were examined by a newly developed time-resolved fluoroimmunoassay (TR-FIA) and immunohistochemistry. A TR-FIA for alpha-MSH was newly developed, and its levels in the pituitary gland and plasma of Japanese flounder reared in a white or black tank for 5 months were compared. A competitive assay using two antibodies was performed among secondary antibodies in the solid phase, alpha-MSH antibodies, samples, and europium-labeled Des-Ac-alpha-MSH. The sensitivity of the assay, defined as twice the standard deviation at a zero dose, was 0.98 ng/ml (49 pg/well). The intra- and interassay coefficients of variation of the assay were 8.8% (n=8) and 17.3% (n=5), respectively, at about 50% binding. Cross-reactivities of Des-Ac-alpha-MSH and Di-Ac-alpha-MSH were about 100%. Cross-reactivities of adrenocorticotropic hormone, salmon gonadotropin-releasing hormone (sGnRH), and chicken GnRH-II were less than 0.2%, and that of melanin-concentrating hormone was less than 2.0% at 50% binding. Displacement curves of serially twofold-diluted hypothalamus extract, pituitary gland extract, and plasma extract of Japanese flounder with the assay buffer were parallel to the alpha-MSH standard curve. Moreover, displacement curves of serially twofold-diluted hypothalamus and/or pituitary gland extract of masu salmon, goldfish, red seabream, Japanese eel, tiger puffer, and barfin flounder with the assay buffer were also parallel to the alpha-MSH standard. In Japanese flounder, total immunoreactive (ir)-alpha-MSH levels in the pituitary gland were lower in the black tank, whereas those in the plasma tended to be higher in the black tank, suggesting that the synthesis and release of alpha-MSH are higher in the black tank. alpha-MSH-ir cells were detected in the pars intermedia and a small part of the pars distalis of the pituitary gland. alpha-MSH-ir cell bodies were located in the basal hypothalamus and alpha-MSH-ir fibers were distributed not only in the hypothalamus but also in the telencephalon, midbrain, cerebellum, and medulla oblongata, suggesting that alpha-MSH functions as a neuromodulator in the brain.

QUASARS PROBING QUASARS. IV. JOINT CONSTRAINTS ON THE CIRCUMGALACTIC MEDIUM FROM ABSORPTION AND EMISSION

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

Hennawi, Joseph F.; Prochaska, J. Xavier, E-mail: xavier@ucolick.org

2013-03-20

We have constructed a sample of 29 close projected quasar pairs where the background quasar spectrum reveals absorption from optically thick H I gas associated with the foreground quasar. These unique sightlines allow us to study the quasar circumgalactic medium (CGM) in absorption and emission simultaneously, because the background quasar pinpoints large concentrations of gas where Ly{alpha} emission, resulting from quasar-powered fluorescence, resonant Ly{alpha} scattering, and/or cooling radiation, is expected. A sensitive search (1{sigma} surface-brightness limits of SB{sub Ly{alpha}}{approx_equal}3 Multiplication-Sign 10{sup -18} erg s{sup -1} cm{sup -2} arcsec{sup -2}) for diffuse Ly{alpha} emission in the environments of the foreground (predominantlymore » radio-quiet) quasars is conducted using Gemini/GMOS and Keck/LRIS slit spectroscopy. We fail to detect large-scale {approx}100 kpc Ly{alpha} emission, either at the location of the optically thick absorbers or in the foreground quasar halos, in all cases except a single system. We interpret these non-detections as evidence that the gas detected in absorption is shadowed from the quasar UV radiation due to obscuration effects, which are frequently invoked in unified models of active galactic nuclei. Small-scale R {approx}< 50 kpc extended Ly{alpha} nebulosities are detected in 34% of our sample, which are likely the high-redshift analogs of the extended emission-line regions (EELRs) commonly observed around low-redshift (z < 0.5) quasars. This may be fluorescent recombination radiation from a population of very dense clouds with a low covering fraction illuminated by the quasar. We also detect a compact high rest-frame equivalent width (W{sub Ly{alpha}} > 50 A) Ly{alpha}-emitter with luminosity L{sub Ly{alpha}} = 2.1 {+-} 0.32 Multiplication-Sign 10{sup 41} erg s{sup -1} at small impact parameter R = 134 kpc from one foreground quasar, and argue that it is more likely to result from quasar-powered fluorescence, than simply be a star-forming galaxy clustered around the quasar. Our observations imply that much deeper integrations with upcoming integral-field spectrometers such as MUSE and KCWI will be able to routinely detect a diffuse Ly{alpha} glow around bright quasars on scales R {approx} 100 kpc and thus directly image the CGM.« less

Effect of alpha-adrenoceptor antagonists (phentolamine, nicergoline and prazosin) on reperfusion arrhythmias and noradrenaline release in perfused rat heart.

PubMed Central

Bralet, J.; Didier, J.; Moreau, D.; Opie, L. H.; Rochette, L.

1985-01-01

Rat isolated hearts were perfused through the left atrium with a modified Krebs-Henseleit solution or mounted on a Langendorff perfusion system. The hearts were prelabelled with [3H]-noradrenaline [( 3H]-NA) and the left main coronary artery was ligated for 10 min after which reperfusion followed. The liberation of [3H]-NA and the development of ventricular tachycardia and fibrillation were monitored throughout. During the occlusion period, ventricular arrhythmias did not occur and heart rate was not significantly altered in the control series. In contrast, reperfusion was followed by ventricular fibrillation and ventricular tachycardia in all the hearts in the control series (Langendorff or 'working' models). The alpha-adrenoceptor antagonists phentolamine (7.1 X 10(-6) M and 7.1 X 10(-5) M) and nicergoline (3.1 X 10(-6) M) diminished or prevented reperfusion arrhythmias. However, prazosin (5.2 X 10(-6) M) was not effective. The lower concentration of phentolamine did not alter the pattern of [3H]-NA release, whereas, high doses of phentolamine and nicergoline increased the release of [3H]-NA. Prazosin (5.2 X 10(-6) M) caused a very marked increase in release of [3H]-NA but was not antiarrhythmic. A 'membrane-stabilizing' effect seems the most appropriate explanation for these antiarrhythmic effects of alpha-antagonist agents. PMID:2858234

Single-stage plasma-based correlated energy spread compensation for ultrahigh 6D brightness electron beams

PubMed Central

Manahan, G. G.; Habib, A. F.; Scherkl, P.; Delinikolas, P.; Beaton, A.; Knetsch, A.; Karger, O.; Wittig, G.; Heinemann, T.; Sheng, Z. M.; Cary, J. R.; Bruhwiler, D. L.; Rosenzweig, J. B.; Hidding, B.

2017-01-01

Plasma photocathode wakefield acceleration combines energy gains of tens of GeV m−1 with generation of ultralow emittance electron bunches, and opens a path towards 5D-brightness orders of magnitude larger than state-of-the-art. This holds great promise for compact accelerator building blocks and advanced light sources. However, an intrinsic by-product of the enormous electric field gradients inherent to plasma accelerators is substantial correlated energy spread—an obstacle for key applications such as free-electron-lasers. Here we show that by releasing an additional tailored escort electron beam at a later phase of the acceleration, when the witness bunch is relativistically stable, the plasma wave can be locally overloaded without compromising the witness bunch normalized emittance. This reverses the effective accelerating gradient, and counter-rotates the accumulated negative longitudinal phase space chirp of the witness bunch. Thereby, the energy spread is reduced by an order of magnitude, thus enabling the production of ultrahigh 6D-brightness beams. PMID:28580954

Development and characterisation of polymeric microparticle of poly(d,l-lactic acid) loaded with holmium acetylacetonate.

PubMed

de Azevedo, Mariangela de Burgos M; de Melo, Vitor H S; Soares, Carlos Roberto J; Miyamoto, Douglas M; Katayama, Ricardo A; Squair, Peterson L; Barros, Caio H N; Tasic, Ljubica

2018-06-14

Biodegradable polymers containing radioactive isotopes such as Holmium 166 ( 166 Ho) have potential applications as beta particle emitters in tumour tissues. It is also a gamma ray emitter, allowing nuclear imaging of any tissue to be acquired. It is frequently used in the form of complexes such as holmium acetylacetonate (HoAcAc), which may cause damages in tissues next to the targets cancer cells, as it is difficult to control its linkage or healthy tissues radiotherapy effects. Poly(d,l-lactic acid), PDLLA, was used to encapsulate holmium acetylacetonate (HoAcAc) using an emulsion solvent extraction/evaporation technique. Microspheres with sizes between 20-53 µm were extensively characterised. HoAcAc release from the microspheres was assessed through studies using Inductively Coupled Plasma - Optical Emission Spectroscopy, and the microspheres showed no holmium leakage after a period of 10 half-lives and following gamma irradiation. Thus, HoAcAc loaded microspheres are here presented as a potential system for brachytherapy and imaging purposes.

Single-stage plasma-based correlated energy spread compensation for ultrahigh 6D brightness electron beams

NASA Astrophysics Data System (ADS)

Manahan, G. G.; Habib, A. F.; Scherkl, P.; Delinikolas, P.; Beaton, A.; Knetsch, A.; Karger, O.; Wittig, G.; Heinemann, T.; Sheng, Z. M.; Cary, J. R.; Bruhwiler, D. L.; Rosenzweig, J. B.; Hidding, B.

2017-06-01

Plasma photocathode wakefield acceleration combines energy gains of tens of GeV m-1 with generation of ultralow emittance electron bunches, and opens a path towards 5D-brightness orders of magnitude larger than state-of-the-art. This holds great promise for compact accelerator building blocks and advanced light sources. However, an intrinsic by-product of the enormous electric field gradients inherent to plasma accelerators is substantial correlated energy spread--an obstacle for key applications such as free-electron-lasers. Here we show that by releasing an additional tailored escort electron beam at a later phase of the acceleration, when the witness bunch is relativistically stable, the plasma wave can be locally overloaded without compromising the witness bunch normalized emittance. This reverses the effective accelerating gradient, and counter-rotates the accumulated negative longitudinal phase space chirp of the witness bunch. Thereby, the energy spread is reduced by an order of magnitude, thus enabling the production of ultrahigh 6D-brightness beams.

TNF{alpha} and IL-1{beta} are mediated by both TLR4 and Nod1 pathways in the cultured HAPI cells stimulated by LPS

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

Zheng, Wenwen; Zheng, Xuexing; Department of Anesthesiology, University of Miami Miller School of Medicine, Miami, FL 33136

2012-04-20

Highlights: Black-Right-Pointing-Pointer LPS induces proinflammatory cytokine release in HAPI cells. Black-Right-Pointing-Pointer JNK pathway is dependent on TLR4 signaling to release cytokines. Black-Right-Pointing-Pointer NF-{kappa}B pathway is dependent on Nod1 signaling to release cytokines. -- Abstract: A growing body of evidence recently suggests that glial cell activation plays an important role in several neurodegenerative diseases and neuropathic pain. Microglia in the central nervous system express toll-like receptor 4 (TLR4) that is traditionally accepted as the primary receptor of lipopolysaccharide (LPS). LPS activates TLR4 signaling pathways to induce the production of proinflammatory molecules. In the present studies, we verified the LPS signaling pathwaysmore » using cultured highly aggressively proliferating immortalized (HAPI) microglial cells. We found that HAPI cells treated with LPS upregulated the expression of TLR4, phospho-JNK (pJNK) and phospho-NF-{kappa}B (pNF-{kappa}B), TNF{alpha} and IL-1{beta}. Silencing TLR4 with siRNA reduced the expression of pJNK, TNF{alpha} and IL-1{beta}, but not pNF-{kappa}B in the cells. Inhibition of JNK with SP600125 (a JNK inhibitor) decreased the expression of TNF{alpha} and IL-1{beta}. Unexpectedly, we found that inhibition of Nod1 with ML130 significantly reduced the expression of pNF-{kappa}B. Inhibition of NF-{kappa}B also reduced the expression of TNF{alpha} and IL-1{beta}. Nod1 ligand, DAP induced the upregulation of pNF-{kappa}B which was blocked by Nod1 inhibitor. These data indicate that LPS-induced pJNK is TLR4-dependent, and that pNF-{kappa}B is Nod1-dependent in HAPI cells treated with LPS. Either TLR4-JNK or Nod1-NF-{kappa}B pathways is involved in the expression of TNF{alpha} and IL-1{beta}.« less

Subaru studies of the cosmic dawn

PubMed Central

IYE, Masanori

2011-01-01

An overview on the current status of the census of the early Universe population is given. Observational surveys of high redshift objects provide direct opportunities to study the early epoch of the Universe. The target population included are Lyman Alpha Emitters (LAE), Lyman Break Galaxies (LBG), gravitationally lensed galaxies, quasars and gamma-ray bursts (GRB). The basic properties of these objects and the methods used to study them are reviewed. The present paper highlights the fact that the Subaru Telescope group made significant contributions in this field of science to elucidate the epoch of the cosmic dawn and to improve the understanding of how and when infant galaxies evolve into mature ones. PMID:22075759

The thalidomide analogue CC-3052 inhibits HIV-1 and tumour necrosis factor-alpha (TNF-alpha) expression in acutely and chronically infected cells in vitro.

PubMed

La Maestra, L; Zaninoni, A; Marriott, J B; Lazzarin, A; Dalgleish, A G; Barcellini, W

2000-01-01

We investigated the in vitro effect of the water-soluble, highly stable thalidomide analogue CC-3052 on HIV-1 expression and TNF-alpha production in latently infected promonocytic U1 cells, acutely infected T cells and monocyte-derived human macrophages (MDM), and in mitogen-stimulated ex vivo cultures from patients with primary acute HIV-1 infection. HIV-1 expression was assessed by Northern blot analysis of RNAs, and ELISA for p24 antigen release and reverse transcriptase (RT) activity. TNF-alpha expression was evaluated by RT-polymerase chain reaction (PCR)-ELISA for mRNA and ELISA for protein secretion. We demonstrated that CC-3052 is able to inhibit HIV-1 expression, as evaluated by mRNA, p24 release and RT activity, in phorbol myristate acetate (PMA)- and cytokine-stimulated U1 cells. Furthermore, CC-3052 inhibited HIV-1 expression, as evaluated by p24 and RT activity, in acutely infected MDM and T cells. As far as TNF-alpha is concerned, CC-3052 significantly reduced TNF-alpha mRNA and protein secretion in PMA-stimulated U937 and U1 cells, and in PMA-stimulated uninfected and acutely infected MDM. Consistently, the addition of CC-3052 reduced TNF-alpha production in phytohaemagglutinin (PHA) and lipopolysaccharide (LPS)-stimulated whole blood cultures from patients during the primary acute phase of HIV-1 infection. Since TNF-alpha is among the most potent enhancers of HIV-1 expression, the effect of CC-3052 on TNF-alpha may account for its inhibitory activity on HIV-1 expression. Given the well documented immunopathological role of TNF-alpha and its correlation with viral load, advanced disease and poor prognosis, CC-3052 could be an interesting drug for the design of therapeutic strategies in association with anti-retroviral agents.

Induction of hypoxia-inducible factor-1alpha and activation of caspase-3 in hypoxia-reoxygenated bone marrow stroma is negatively regulated by the delayed production of substance P.

PubMed

Qian, J; Ramroop, K; McLeod, A; Bandari, P; Livingston, D H; Harrison, J S; Rameshwar, P

2001-10-15

The bone marrow (BM), which is the major site of immune cell development in the adult, responds to different stimuli such as inflammation and hemorrhagic shock. Substance P (SP) is the major peptide encoded by the immune/hemopoietic modulator gene, preprotachykinin-1 (PPT-I). Differential gene expression using a microarray showed that SP reduced hypoxia-inducible factor-1alpha (HIF-1alpha) mRNA levels in BM stroma. Because long-term hypoxia induced the expression of PPT-I in BM mononuclear cells, we used timeline studies to determine whether PPT-I is central to the biologic responses of BM stroma subjected to 30-min hypoxia (pO(2) = 35 mm Hg) followed by reoxygenation. HIF-1alpha mRNA and protein levels were increased up to 12 h. At this time, beta-PPT-I mRNA was detected with the release of SP at 16 h. SP release correlated with down-regulation of HIF-1alpha to baseline. A direct role for SP in HIF-1alpha expression was demonstrated as follows: 1) transient knockout of beta-PPT-I showed an increase in HIF-1alpha expression up to 48 h of reoxygenation; and 2) HIF-1alpha expression remained baseline during reoxygenation when stroma was subjected to hypoxia in the presence of SP. Reoxygenation activated the PPT-I promoter with concomitant nuclear translocation of HIF-1alpha that can bind to the respective consensus sequences within the PPT-I promoter. SP reversed active caspase-3, an indicator of apoptosis and erythropoiesis, to homeostasis level after reoxygenation of hypoxic stroma. The results show that during reoxgenation the PPT-I gene acts as a negative regulator on the expression of HIF-1alpha and active caspase-3 in BM stroma subjected to reoxygenation.

Topological dispositions of lysine. alpha. 380 and lysine. gamma. 486 in the acetylcholine receptor from Torpedo californica

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

Dwyer, B.P.

1991-04-23

The locations have been determined, with respect to the plasma membrane, of lysine {alpha}380 and lysine {gamma}486 in the {alpha} subunit and the {gamma} subunit, respectively, of the nicotinic acetylcholine receptor from Torpedo californica. Immunoadsorbents were constructed that recognize the carboxy terminus of the peptide GVKYIAE released by proteolytic digestion from positions 378-384 in the amino acid sequence of the {alpha} subunit of the acetylcholine receptor and the carboxy terminus of the peptide KYVP released by proteolytic digestion from positions 486-489 in the amino acid sequence of the {gamma} subunit. They were used to isolate these peptides from proteolytic digestsmore » of polypeptides from the acetylcholine receptor. Sealed vesicles containing the native acetylcholine receptor were labeled with pyridoxal phosphate and sodium ({sup 3}H)-borohydride. The effect of saponin on the incorporation of pyridoxamine phosphate into lysine {alpha}380 and lysine {gamma}486 from the acetylcholine receptor in these vesicles was assessed with the immunoadsorbents. The conclusions that follow from these results are that lysine {alpha}380 is on the inside surface of a vesicle and lysine {gamma}486 is on the outside surface. Because a majority (85%) of the total binding sites for {alpha}-bungarotoxin bind the toxin in the absence of saponin, the majority of the vesicles are right side out with the inside of the vesicle corresponding to the cytoplasmic surface and the outside of the vesicle corresponding to the extracytoplasmic, synaptic surface. Because lysine {alpha}380 and lysine {gamma}486 lie on opposite sides of the membrane, a membrane-spanning segment must be located between the two positions occupied by these two amino acids in the common sequence of a polypeptide of the acetylcholine receptor.« less

Alpha lipoic acid protects the heart against myocardial post ischemia-reperfusion arrhythmias via KATP channel activation in isolated rat hearts.

PubMed

Dudek, Magdalena; Knutelska, Joanna; Bednarski, Marek; Nowiński, Leszek; Zygmunt, Małgorzata; Bilska-Wilkosz, Anna; Iciek, Małgorzata; Otto, Monika; Żytka, Iwona; Sapa, Jacek; Włodek, Lidia; Filipek, Barbara

2014-06-01

The cardiovascular effects of alpha lipoic acid were evaluated in isolated rat hearts exposed to ischemia-reperfusion injury in vitro. Alpha-lipoic acid raised the level of sulfane sulfur playing an important role in the release of hydrogen sulfide. H2S was shown to prevent the post-reperfusion arrhythmias and to protect the cardiomyocytes from death caused by hypoxia. The activation of potassium ATP-sensitive channels (K(ATP) channels) is one of the most important mechanisms of action of hydrogen sulfide in the cardiovascular system. The aim of this study was to investigate whether alpha lipoic acid can prevent the occurrence of post-reperfusion arrhythmias in vitro using a Langendorff model of ischemia-reperfusion in rats affecting the K(ATP) channels. Alpha lipoic acid significantly improved post-reperfusion cardiac function (reducing incidence of arrhythmias), especially in a dose of 10(-7)M. These cardiovascular effects of this compound on the measured parameters were reversed by glibenclamide, a selective K(ATP) blocker. Alpha lipoic acid increased the level of sulfane sulfur in the hearts. This may suggest that the positive effects caused by alpha lipoic acid in the cardiovascular system are not only related to its strong antioxidant activity, and the influence on the activity of such enzymes as aldehyde dehydrogenase 2, as previously suggested, but this compound can affect K(ATP) channels. It is possible that this indirect effect of alpha lipoic acid is connected with changes in the release of sulfane sulfur and hydrogen sulfide. Copyright © 2014 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

Local inflammation, lethality and cytokine release in mice injected with Bothrops atrox venom.

PubMed Central

Barros, S F; Friedlanskaia, I; Petricevich, V L; Kipnis, T L

1998-01-01

We have provided evidence that: (a) lethality of mice to crude Bothrops venom varies according the isogenic strain (A/J > C57Bl/6 > A/Sn > BALB/c > C3H/HePas > DBA/2 > C3H/He); (b)BALB/c mice (LD50=100.0 microg) were injected i.p. with 50 microg of venom produced IL-6, IL-10, INF-gamma, TNF-alpha and NO in the serum. In vitro the cells from the mice injected and challenged with the venom only released IL-10 while peritoneal macrophages released IL-10, INF-gamma and less amounts of IL-6; (c) establishment of local inflammation and necrosis induced by the venom, coincides with the peaks of TNF-alpha, IFN-gamma and NO and the damage was neutralized when the venom was incubated with a monoclonal antibody against a 60 kDa haemorrhagic factor. These results suggest that susceptibility to Bothrops atrox venom is genetically dependent but MHC independent; that IL-6, IL-10, TNF-alpha, IFN-gamma and NO can be involved in the mediation of tissue damage; and that the major venom component inducers of the lesions are haemorrhagins. PMID:9883969

Sport expertise: the role of precise timing of verbal-analytical engagement and the ability to detect visual cues.

PubMed

Taliep, Mogammad Sharhidd; John, Lester

2014-01-01

This study proposed that relative timing of high-alpha (10-12 Hz) left (T3) and right (T4) cortical temporal electroencephalographic (EEG) power levels would differentiate performance groups in a reactive sport such as cricket batting. The time course of EEG event-related alpha synchronisation (ERS) and desynchronisation was investigated in two groups (eight skilled and ten less skilled) of right-handed cricket batsmen whilst viewing projected video footage of a bowler delivering a randomised series of 24 deliveries repeated 10 times (total of 240 deliveries). Ball release from the bowler's hand was used as the corresponding reaction cue. Participants were instructed to press one of two buttons on a keypad to identify in-swingers or out-swingers. T3 ERS was significantly greater in skilled batsmen from approximately 1500 ms prior to ball release, but differences reduced close to ball release, reaching nonsignificance by 250 ms. There was no significant difference in T4 between the groups. This study uniquely highlights that the relative timing of the T3 high-alpha ERS state appears to differentiate batting skill groups in a reactive task.

A Comparative Study of QD and Nitrogen-Based 1.3 mu m VCSELs

DTIC Science & Technology

2001-06-01

molecular beam epitaxy (MBE) proposed as promising candidates for 1.3 /tm emitters. Among them InGaAsN quantum well (QW) and InGaAs quantum dots (QD... VCSELs DISTRIBUTION: Approved for public release, distribution unlimited Availability: Hard copy only. This paper is part of the following report: TITLE...and Technology" LOED.02 St Petersburg, Russia, June 18-22, 2001 ©0 2001 loffe Institute A comparative study of QD and nitrogen-based 1.3 /tm VCSELs A. P

Neutrophil contribution to the crescentic glomerulonephritis in SCG/Kj mice.

PubMed

Ishida-Okawara, Akiko; Ito-Ihara, Toshiko; Muso, Eri; Ono, Takahiko; Saiga, Kan; Nemoto, Kyuichi; Suzuki, Kazuo

2004-07-01

Myeloperoxidase-specific anti-neutrophil cytoplasmic auto-antibody (MPO-ANCA) has been a useful diagnostic marker in systemic vasculitis with crescentic glomerulonephritis (CrGN). It is highly suspected that the antigenic enzyme MPO released from activated neutrophils is involved in these lesions. We evaluated the relationship between neutrophil functions including peripheral neutrophil counts and renal lesions in SCG/Kj mice as a model of ANCA-associated CrGN and vasculitis. Peripheral neutrophil counts, the plasma levels of MPO-ANCA and tumour necrosis factor alpha (TNF-alpha) were measured. The capacity of MPO release and superoxide generation were evaluated as neutrophil activity. The renal lesions were estimated by grade of proteinuria, histopathological lesion, such as glomerular neutrophil infiltration and active or chronic renal injury scores with crescent formation. MPO-ANCA and TNF-alpha levels were higher than those of normal mice C57BL/6 even before overt proteinuria; subsequently, peripheral neutrophils increased. In the phase of nephritis with low grade proteinuria, the spontaneous release of MPO from peripheral neutrophils increased, while superoxide generation increased before spontaneous MPO release occurred. In addition, the renal lesion in histological observations was aggravated with ageing and the glomerular neutrophil infiltration was positively correlated with MPO-ANCA levels, as well as with histological indices of nephritis, active renal injury score; in particular, crescent formation was correlated with spontaneous MPO release. In contrast, superoxide generation was negatively correlated with the severity of this lesion during the progression. These findings indicate that neutrophils are activated and contribute to the development of the active crescentic lesion in SCG/Kj mice.

Monolithic multinozzle emitters for nanoelectrospray mass spectrometry

DOEpatents

Wang, Daojing [Daly City, CA; Yang, Peidong [Kensington, CA; Kim, Woong [Seoul, KR; Fan, Rong [Pasadena, CA

2011-09-20

Novel and significantly simplified procedures for fabrication of fully integrated nanoelectrospray emitters have been described. For nanofabricated monolithic multinozzle emitters (NM.sup.2 emitters), a bottom up approach using silicon nanowires on a silicon sliver is used. For microfabricated monolithic multinozzle emitters (M.sup.3 emitters), a top down approach using MEMS techniques on silicon wafers is used. The emitters have performance comparable to that of commercially-available silica capillary emitters for nanoelectrospray mass spectrometry.

Asymmetrical field emitter

DOEpatents

Fleming, J.G.; Smith, B.K.

1995-10-10

A method is disclosed for providing a field emitter with an asymmetrical emitter structure having a very sharp tip in close proximity to its gate. One preferred embodiment of the present invention includes an asymmetrical emitter and a gate. The emitter having a tip and a side is coupled to a substrate. The gate is connected to a step in the substrate. The step has a top surface and a side wall that is substantially parallel to the side of the emitter. The tip of the emitter is in close proximity to the gate. The emitter is at an emitter potential, and the gate is at a gate potential such that with the two potentials at appropriate values, electrons are emitted from the emitter. In one embodiment, the gate is separated from the emitter by an oxide layer, and the emitter is etched anisotropically to form its tip and its asymmetrical structure. 17 figs.

Effects of 17alpha-methyltestosterone on seminal vesicle development and semen release response in the African catfish, Clarias gariepinus.

PubMed

Viveiros, A T; Eding, E H; Komen, J

2001-11-01

The effects of 17alpha-methyltestosterone on seminal vesicle development in the African catfish, Clarias gariepinus, were investigated in an attempt to improve semen collection from this species. Treatment of larvae with dietary 17alpha-methyltestosterone at 50 mg kg(-1) for days 12-33 or days 12-40 after hatching, or at 20 mg kg(-1) for days 12-26, 12-33, 12-40 or 12-47 after hatching inhibited the development of the seminal vesicle finger-like extensions in male catfish, but did not affect the sex ratio. The minimum effective dose and period of treatment to inhibit seminal vesicle development in all male catfish treated with 17alpha-methyltestosterone was 20 mg kg(-1) for days 12-40 after hatching. Male catfish from this treatment group developed normal testes that, in some cases, contained a few oocytes, which tended to disappear before sexual maturation. After sexual maturation, the semen release response was evaluated in males with incomplete seminal vesicles. Fluid with viable spermatozoa was obtained after two consecutive injections of carp pituitary suspension, from 10 of 19 males that had been fed 20 mg 17alpha-methyltestosterone kg(-1) for days 12-40 or days 12-47 after hatching, but from only 4 of 15 males that did not receive any dietary steroid. Intratesticular semen quality was not affected by 17alpha-methyltestosterone treatment. The results of this study demonstrate that the absence of seminal vesicle extensions induced by treatment with 17alpha-methyltestosterone facilitated the collection of semen by stripping from this species of fish.

Macrophage activation by factors released from acetaminophen-injured hepatocytes: Potential role of HMGB1

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

Dragomir, Ana-Cristina; Laskin, Jeffrey D.; Laskin, Debra L., E-mail: laskin@eohsi.rutgers.edu

2011-06-15

Toxic doses of acetaminophen (AA) cause hepatocellular necrosis. Evidence suggests that activated macrophages contribute to the pathogenic process; however, the factors that activate these cells are unknown. In these studies, we assessed the role of mediators released from AA-injured hepatocytes in macrophage activation. Treatment of macrophages with conditioned medium (CM) collected 24 hr after treatment of mouse hepatocytes with 5 mM AA (CM-AA) resulted in increased production of reactive oxygen species (ROS). Macrophage expression of heme oxygenase-1 (HO-1) and catalase mRNA was also upregulated by CM-AA, as well as cyclooxygenase (COX)-2 and 12/15-lipoxygenase (LOX). CM-AA also upregulated expression of themore » proinflammatory chemokines, MIP-1{alpha} and MIP-2. The effects of CM-AA on expression of COX-2, MIP-1{alpha} and MIP-2 were inhibited by blockade of p44/42 MAP kinase, suggesting a biochemical mechanism mediating macrophage activation. Hepatocytes injured by AA were found to release HMGB1, a potent macrophage activator. This was inhibited by pretreatment of hepatocytes with ethyl pyruvate (EP), which blocks HMGB1 release. EP also blocked CM-AA induced ROS production and antioxidant expression, and reduced expression of COX-2, but not MIP-1{alpha} or MIP-2. These findings suggest that HMGB1 released by AA-injured hepatocytes contributes to macrophage activation. This is supported by our observation that expression of the HMGB1 receptor RAGE is upregulated in macrophages in response to CM-AA. These data indicate that AA-injured hepatocytes contribute to the inflammatory environment in the liver through the release of mediators such as HMGB1. Blocking HMGB1/RAGE may be a useful approach to limiting classical macrophage activation and AA-induced hepatotoxicity. - Research Highlights: > These studies analyze macrophage activation by mediators released from acetaminophen-damaged hepatocytes. > Factors released from acetaminophen-injured hepatocytes induce macrophage ROS production and expression of COX-2, chemokines, and RAGE. > Hepatocyte-mediated macrophage activation involves p44/42 MAP kinase signaling. > HMGB1 is released from acetaminophen-injured hepatocytes and contributes to macrophage activation.« less

Monte Carlo calculation of the maximum therapeutic gain of tumor antivascular alpha therapy

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

Huang, Chen-Yu; Oborn, Bradley M.; Guatelli, Susanna

Purpose: Metastatic melanoma lesions experienced marked regression after systemic targeted alpha therapy in a phase 1 clinical trial. This unexpected response was ascribed to tumor antivascular alpha therapy (TAVAT), in which effective tumor regression is achieved by killing endothelial cells (ECs) in tumor capillaries and, thus, depriving cancer cells of nutrition and oxygen. The purpose of this paper is to quantitatively analyze the therapeutic efficacy and safety of TAVAT by building up the testing Monte Carlo microdosimetric models. Methods: Geant4 was adapted to simulate the spatial nonuniform distribution of the alpha emitter {sup 213}Bi. The intraluminal model was designed tomore » simulate the background dose to normal tissue capillary ECs from the nontargeted activity in the blood. The perivascular model calculates the EC dose from the activity bound to the perivascular cancer cells. The key parameters are the probability of an alpha particle traversing an EC nucleus, the energy deposition, the lineal energy transfer, and the specific energy. These results were then applied to interpret the clinical trial. Cell survival rate and therapeutic gain were determined. Results: The specific energy for an alpha particle hitting an EC nucleus in the intraluminal and perivascular models is 0.35 and 0.37 Gy, respectively. As the average probability of traversal in these models is 2.7% and 1.1%, the mean specific energy per decay drops to 1.0 cGy and 0.4 cGy, which demonstrates that the source distribution has a significant impact on the dose. Using the melanoma clinical trial activity of 25 mCi, the dose to tumor EC nucleus is found to be 3.2 Gy and to a normal capillary EC nucleus to be 1.8 cGy. These data give a maximum therapeutic gain of about 180 and validate the TAVAT concept. Conclusions: TAVAT can deliver a cytotoxic dose to tumor capillaries without being toxic to normal tissue capillaries.« less

DETERMINATION AND DOSE CONTRIBUTION OF URANIUM ISOTOPES AND 210Po ACTIVITY CONCENTRATIONS OF NATURAL SPRING WATERS IN THE PROVINCE OF GRANADA, SPAIN.

PubMed

Milena-Pérez, A; Piñero-García, F; Expósito-Suárez, V M; Mantero, J; Benavente, J; Ferro-García, M A

2018-03-01

The activity concentrations of alpha-emitters comprising isotopes of uranium (238, 234, 235U) and polonium (210Po) were measured using alpha-particle spectrometry in natural spring waters in the province of Granada, Spain. These water are consumed by the population of the zone who live in villages. This is almost half of the population of the whole region. Mean values of activity concentrations found are 42.61 ± 2.66; 49.55 ± 3.03; 1.64 ± 0.28 and 1.74 ± 0.15 mBq L-1 for 238U, 234U, 235U and 210Po, respectively. Finally, the radiological impact of the analysed waters has been determined, in terms of the estimation of the committed annual effective dose due to the ingestion of the water. The assessment has been carried out for five age groups with the aim to cover all the population. The calculated annual effective doses are observed to be below the prescribed dose limit of 100 μSv y-1 recommended by WHO.

Reappraisal of solid selective emitters

NASA Technical Reports Server (NTRS)

Chubb, Donald L.

1990-01-01

New rare earth oxide emitters show greater efficiency than previous emitters. As a result, based on a simple model the efficiency of these emitters was calculated. Results indicate that the emission band of the selective emitter must be at relatively low energy (less than or equal to .52 eV) to obtain maximum efficiency at moderate emitter temperatures (less than or equal to 1500 K). Thus low bandgap energy PV materials are required to obtain an efficient thermophotovoltaic (TPV) system. Of the 4 specific rare earths (Nd, Ho, Er, Yb) studied Ho has the largest efficiency at moderate temperatures (72 percent at 1500 K). A comparison was made between a selective emitter TPV system and a TPV system that uses a thermal emitter plus a band pass filter to make the thermal emitter behave like a selective emitter. Results of the comparison indicate that only for very optimistic filter and thermal emitter properties will the filter TPV system have a greater efficiency than the selective emitter system.

77 FR 71462 - Blackstone Alternative Alpha Fund, et al.; Notice of Application

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-30

... Breakpoint Discounts by Mutual Funds, Investment Company Act Release No. 26464 (June 7, 2004) (adopting... Transactions and Certain Mutual Funds and Other Securities, and Other Confirmation Requirement Amendments, and Amendments to the Registration Form for Mutual Funds, Investment Company Act Release No. 26341 (Jan. 29, 2004...

Oxytocin induces prostaglandin F2 alpha release in pregnant cows: influence of gestational age and oxytocin receptor concentrations.

PubMed

Fuchs, A R; Rollyson, M K; Meyer, M; Fields, M J; Minix, J M; Randel, R D

1996-03-01

Brahman cows with known breeding dates received i.v. injections of either 10 or 100 IU oxytocin (OT) on Days 50, 150, 250, or 280 of gestation (n = 6 for each stage). Concentrations of the prostaglandin (PG) F2 alpha metabolite, 13,14-dihydro-15-keto-prostaglandin (PGFM), and OT were measured in samples of peripheral plasma collected at 15-min intervals for 1 h before and 1 h after treatment and then at 30-min intervals for 3 h. Plasma progesterone was measured daily for 14 days after OT injections on Days 50 and 250 of gestation. The increase in plasma OT after injection was dose-dependent (p = 0.001) but not affected by stage of gestation. Plasma PGFM increased after OT in a dose- and stage-dependent manner (p = 0.0001). At Day 280, the increase in plasma PGFM after 100 IU OT was sevenfold greater than at Day 50. Plasma progesterone declined significantly during the 7th to 12th days postinjection and returned to normal pregnancy values by the 14th day (4.4 +/- 0.3 ng/ml) except in two cows treated on Day 50 of gestation that later aborted. In these, plasma progesterone was significantly lower, 2.6 +/- 0.1 ng/ml. In a second experiment, the concentration of OT receptors was determined in endometrium collected from purebred Angus or Hereford cows slaughtered on Days 50, 150, 250, and 280 of gestation (n = 3 or 4 at each stage). Endometrial concentrations of OT receptor changed as a function of gestational age, increasing sixfold from Day 50 to Day 280, which was parallel to the increase by OT of plasma PGFM. Thus, endometrial OT receptors are functionally coupled to PGF2 alpha release during pregnancy, and their concentration determines the magnitude of OT-induced PGF2 alpha release during gestation. Consequently, endogenous OT is a factor in the regulation of PGF2 alpha release from the bovine uterus during pregnancy and parturition.

Nicergoline stimulates protein kinase C mediated alpha-secretase processing of the amyloid precursor protein in cultured human neuroblastoma SH-SY5Y cells.

PubMed

Cedazo-Minguez, A; Bonecchi, L; Winblad, B; Post, C; Wong, E H; Cowburn, R F; Benatti, L

1999-10-01

We investigated the ability of the antidementia agents, nicergoline, aniracetam and hydergine to stimulate PKC mediated alpha-secretase amyloid precursor protein (APP) processing in cultured human neuroblastoma SH-SY5Y cells. Western immunoblotting of cell conditioned media using the Mabs 22C11 and 6E10 revealed the presence of 2 bands with molecular mass of 90 and 120 kDa, corresponding to possible alternatively glycosylated forms of secreted APP (APPs). Short-term (30 min and 2 h) treatment of cells with nicergoline gave an increased intensity of both bands, compared to non-treated cells. Maximal nicergoline effects, of the order of 150-200% over basal APPs release, were seen at concentrations between 1 and 10 microM. Under the same condition, 1 microM PdBu, used as a positive control, gave 500-1000% increases of basal APPs release. In contrast, aniracetam and hydergine, did not show any effect on APPs secretion. 2 h treatment with nicergoline had no effect on cellular full-length APP levels, as determined by immunoblotting of cell extracts with 22C11 and CT15 antibodies. Immunoblotting with PKC isoform specific antibodies of soluble and membrane fractions prepared from 2 h treated cells, showed that nicergoline (50 microM) and PdBu (1 microM) both induced translocation of PKC alpha, gamma and epsilon, but not PKC beta. The involvement of PKC in mediating nicergoline stimulated APPs release was also studied using specific inhibitors. 1 microM calphostin C, a broad range PKC inhibitor, significantly reduced both PdBu (1 microM) and nicergoline (10 microM) induced APPs release. In contrast, Go6976 (1 microM), a selective PKC alpha and beta1 inhibitor, as well as the cAMP-dependent protein kinase inhibitor, H89 (1 microM) were without effect. These results indicate that nicergoline can modulate alpha-secretase APP processing by a PKC dependent mechanism that is likely to involve the gamma and epsilon isoforms of this enzyme.

Comparison of U.S. Environmental Protection Agency’s CAP88 PC versions 3.0 and 4.0

DOE PAGES

Jannik, Tim; Farfan, Eduardo B.; Dixon, Ken; ...

2015-08-01

The Savannah River National Laboratory (SRNL) with the assistance of Georgia Regents University, completed a comparison of the U.S. Environmental Protection Agency's (EPA) environmental dosimetry code CAP88 PC V3.0 with the recently developed V4.0. CAP88 is a set of computer programs and databases used for estimation of dose and risk from radionuclide emissions to air. At the U.S. Department of Energy's Savannah River Site, CAP88 is used by SRNL for determining compliance with EPA's National Emission Standards for Hazardous Air Pollutants (40 CFR 61, Subpart H) regulations. Using standardized input parameters, individual runs were conducted for each radionuclide within itsmore » corresponding database. Some radioactive decay constants, human usage parameters, and dose coefficients changed between the two versions, directly causing a proportional change in the total effective 137Cs, 3H, 129I, 239Pu, and 90Sr) is provided. In general, the total effective doses will decrease for alpha/beta emitters because of reduced inhalation and ingestion rates in V4.0. However, for gamma emitters, such as 60Co and 137Cs, the total effective doses will increase because of changes EPA made in the external ground shine calculations.« less

Tuning Into Brown Dwarfs: Long-Term Radio Monitoring of Two Very Low Mass Dwarfs

NASA Astrophysics Data System (ADS)

Van Linge, Russell; Burgasser, Adam J.; Melis, Carl; Williams, Peter K. G.

2017-01-01

The very lowest-mass (VLM) stars and brown dwarfs, with effective temperatures T < 3000 K, exhibit mixed magnetic activity trends, with H-alpha and X-ray emission that declines rapidly beyond type M7/M8, but persistent radio emission in roughly 10-20% of sources. The dozen or so VLM radio emitters known show a broad range of emission characteristics and time-dependent behavior, including steady persistent emission, periodic oscillations, periodic polarized bursts, and aperiodic flares. Understanding the evolution of these variability patterns, and in particular whether they undergo solar-like cycles, requires long-term monitoring. We report the results of a long-term JVLA monitoring program of two magnetically-active VLM dwarf binaries, the young M7 2MASS 1314+1320AB and older L5 2MASS 1315-2649AB. On the bi-weekly cadence, 2MASS 1314 continues to show variability by revealing regular flaring while 2MASS 1315 continues to be a quiescent emitter. On the daily time scale, both sources show a mean flux density that can vary significantly just over a few days. These results suggest long-term radio behavior in radio-emitting VLM dwarfs is just as diverse and complex as short-term behavior.

Rare Earth Garnet Selective Emitter

NASA Technical Reports Server (NTRS)

Lowe, Roland A.; Chubb, Donald L.; Farmer, Serene C.; Good, Brian S.

1994-01-01

Thin film Ho-YAG and Er-YAG emitters with a platinum substrate exhibit high spectral emittance in the emission band (epsilon(sub lambda) approx. = 0.75, sup 4)|(sub 15/2) - (sup 4)|(sub 13/2),for Er-YAG and epsilon(sub lambda) approx. = 0.65, (sup 5)|(sub 7) - (sup 5)|(sub 8) for Ho-YAG) at 1500 K. In addition, low out-of-band spectral emittance, epsilon(sub lambda) less than 0.2, suggest these materials would be excellent candidates for high efficiency selective emitters in thermophotovoltaic (TPV) systems operating at moderate temperatures (1200-1500 K). Spectral emittance measurements of the thin films were made (1.2 less than lambda less than 3.0 microns) and compared to the theoretical emittances calculated using measured values of the spectral extinction coefficient. In this paper we present the results for a new class of rare earth ion selective emitters. These emitters are thin sections (less than 1 mm) of yttrium aluminum garnet (YAG) single crystal with a rare earth substitutional impurity. Selective emitters in the near IR are of special interest for thermophotovoltaic (TPV) energy conversion. The most promising solid selective emitters for use in a TPV system are rare earth oxides. Early spectral emittance work on rare earth oxides showed strong emission bands in the infrared (0.9 - 3 microns). However, the emittance outside the emission band was also significant and the efficiency of these emitters was low. Recent improvements in efficiency have been made with emitters fabricated from fine (5 - 10 microns) rare earth oxide fibers similar to the Welsbach mantle used in gas lanterns. However, the rare earth garnet emitters are more rugged than the mantle type emitters. A thin film selective emitter on a low emissivity substrate such as gold, platinum etc., is rugged and easily adapted to a wide variety of thermal sources. The garnet structure and its many subgroups have been successfully used as hosts for rare earth ions, introduced as substitutional impurities, in the development of solid state laser crystals. Doping, dependent on the particular ion and crystal structure, may be as high as 100 at. % (complete substitution of yttrium ion with the rare earth ion). These materials have high melting points, 1940 C for YAG (Yttrium Aluminum Garnet), and low emissivity in the near infrared making them excellent candidates for a thin film selective emitter. As previously stated, the spectral emittance of a rare earth emitter is characterized by one or more well defined emission bands. Outside the emission band the emittance(absorptance) is much lower. Therefore, it is expected that emission outside the band for a thin film selective emitter will be dominated by the emitter substrate. For an efficient emitter (power in the emission band/total emitted power) the substrate must have low emittance, epsilon(sub S). This paper presents normal spectral emittance, epsilon(sub lambda), measurements of holmium(Ho) and erbium (Er) doped YAG thin film selective emitters at (1500 K), and compares those results with the theoretical spectral emittance.

Development of Bioorthogonally Degradable Linkers and Polymers Using alpha-Azidoethers

NASA Astrophysics Data System (ADS)

Rajagopalan, Chandrasekhar Ramasubramanian

Degradable polymers have gained a lot of attention in recent years for applications in biotechnology and medicine. External control over polymer degradation can be obtained by incorporating functional groups that cleave in the presence of triggers that would normally be absent in biological environments, i.e. are bioorthogonal. This thesis explores the use of chemically cleavable alpha-azidoethers as a new method to obtain external control over the degradation behavior of polymers. My first goal is to illustrate the potential of alpha-azidoethers toward developing cleavable linkers. We have studied the relationship between alpha-azidoether structure and hydrolytic stability, to prepare linkers that withstand background hydrolytic cleavage until they are exposed to the cleaving trigger. The cleavage kinetics of the alpha-azidoether functional group was quantified. In addition to the conventionally used tris(2-carboxyethyl)phosphine (TCEP), dihydrolipoic acid (DHLA), a previously unexplored, biocompatible reducing agent, was also evaluated as a cleaving trigger. Based on these results, we have proposed design rules for utilizing alpha-azidoethers as cleavable linkers in applications that require bioorthogonal control over linker cleavage. Secondly, the alpha-azidoether cleavable linker chemistry was implemented into the development of polymeric materials. Two different types of polymers were developed. Polyamides incorporating alpha-azidoethers along the backbone were synthesized, and their physical properties and chemically triggered degradation behavior were characterized. The degradation timescale of these polymers can be tuned simply by manipulating the concentration of the externally applied chemical trigger. The alpha-azidoether functional group was then utilized to develop a unique triggered-release polymeric adhesive for potential applications in dental adhesive formulations. A methacrylamide-phosphonate adhesive monomer incorporating an alpha-azidoether group was designed and synthesized. The monomer was polymerized to adhere polymer-composite substrates. Adhesion strength was quantified, and on-demand release of bonded substrates was demonstrated using DHLA as a trigger. The results presented here shed some light on the scope, advantages and drawbacks of utilizing alpha-azidoethers to develop new types of cleavable linkers and degradable polymers. In principle, the triggered degradation method described here could be incorporated into polymers with different chemical structures, to develop a variety of materials that offer an external control over degradation.

Dosimetry of radium-223 and progeny

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

Fisher, D.R.; Sgouros, G.

Radium-223 is a short-lived (11.4 d) alpha emitter with potential applications in radioimmunotherapy of cancer. Radium-223 can be complexed and linked to protein delivery molecules for specific tumor-cell targeting. It decays through a cascade of short-lived alpha- and beta-emitting daughters with emission of about 28 MeV of energy through complete decay. The first three alpha particles are essentially instantaneous. Photons associated with Ra-223 and progeny provide the means for tumor and normal-organ imaging and dosimetry. Two beta particles provide additional therapeutic value. Radium-223 may be produced economically and in sufficient amounts for widescale application. Many aspects of the chemistry ofmore » carrier-free isotope preparation, complexation, and linkage to the antibody have been developed and are being tested. The radiation dosimetry of a Ra-223-labeled antibody shows favorable tumor to normal tissue dose ratios for therapy. The 11.4-d half-life of Ra-223 allows sufficient time for immunoconjugate preparation, administration, and tumor localization by carrier antibodies before significant radiological decay takes place. If 0.01 percent of a 37 MBq (1 mCi) injection deposits in a one gram tumor mass, and if the activity is retained with a typical effective half-time (75 h), the absorbed dose will be 163 mGy MBq{sup {minus}1} (600 rad mCi{sup {minus}1}) administered. 49 refs., 5 figs., 2 tabs.« less

Shielding in ungated field emitter arrays

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

Harris, J. R.; Jensen, K. L.; Shiffler, D. A.

Cathodes consisting of arrays of high aspect ratio field emitters are of great interest as sources of electron beams for vacuum electronic devices. The desire for high currents and current densities drives the cathode designer towards a denser array, but for ungated emitters, denser arrays also lead to increased shielding, in which the field enhancement factor β of each emitter is reduced due to the presence of the other emitters in the array. To facilitate the study of these arrays, we have developed a method for modeling high aspect ratio emitters using tapered dipole line charges. This method can bemore » used to investigate proximity effects from similar emitters an arbitrary distance away and is much less computationally demanding than competing simulation approaches. Here, we introduce this method and use it to study shielding as a function of array geometry. Emitters with aspect ratios of 10{sup 2}–10{sup 4} are modeled, and the shielding-induced reduction in β is considered as a function of tip-to-tip spacing for emitter pairs and for large arrays with triangular and square unit cells. Shielding is found to be negligible when the emitter spacing is greater than the emitter height for the two-emitter array, or about 2.5 times the emitter height in the large arrays, in agreement with previously published results. Because the onset of shielding occurs at virtually the same emitter spacing in the square and triangular arrays, the triangular array is preferred for its higher emitter density at a given emitter spacing. The primary contribution to shielding in large arrays is found to come from emitters within a distance of three times the unit cell spacing for both square and triangular arrays.« less

Natural and Fukushima-derived radioactivity in macroalgae and mussels along the Japanese shoreline

NASA Astrophysics Data System (ADS)

Baumann, Z.; Casacuberta, N.; Baumann, H.; Masqué, P.; Fisher, N. S.

2013-02-01

Following the failure of the nuclear power plant in Fukushima Prefecture in March 2011, peer-reviewed publications describing radioactivity levels in organisms inhabiting coastal environments are scarce. This paper reports on elevated levels of 134Cs and 137Cs in macroalgae and mussels (up to ~ 800 Bq kg-1 dry wt.) in June 2011. Cs concentrations in biota sampled in early June 2011 were higher in areas south of Fukushima than sampled in the last third of the month north of Fukushima. Radioactivity from 134+137Cs in organisms south of Fukushima were comparable to or lower than that from the naturally occuring 40K in the same samples. While 210Pb and 210Po concentrations were generally lower than these other radionuclides, 210Po as an α-emitter is more significant from a radiological viewpoint than γ-emitters as it can inflict greater biological damage. By applying known bioconcentration factors of Cs in biota, measured biota concentrations of Cs were also used to estimate Cs concentraitons in coastal seawater to be in the range of 102-103 Bq m-3. These estimates show that 3 months after the accident and maximal release of radioactive Cs, levels of Cs persisted in coastal waters, although at levels that were two orders of magnitude lower than at the time of release. These June coastal seawater Cs levels were four orders of magnitude above Cs concentrations off Japan prior to the Fukushima disaster.

Natural and Fukushima-derived radioactivity in macroalgae and mussels along the Japanese shoreline

NASA Astrophysics Data System (ADS)

Baumann, Z.; Casacuberta, N.; Baumann, H.; Masqué, P.; Fisher, N. S.

2013-06-01

Following the failure of the nuclear power plant in Fukushima Prefecture in March 2011, peer-reviewed publications describing radioactivity levels in organisms inhabiting coastal environments are scarce. This paper reports on elevated levels of 134Cs and 137Cs in macroalgae and mussels (up to ~ 800 Bq kg-1 dry wt.) in June 2011. Cs concentrations in biota sampled in early June 2011 were higher in areas south of Fukushima than sampled in the last third of the month north of Fukushima. Activity concentrations from 134+137Cs in organisms south of Fukushima were comparable to or lower than those from the naturally occurring 40K in the same samples. While 210Pb and 210Po concentrations were generally lower than these other radionuclides, 210Po as an α-emitter is more significant from a radiological viewpoint than γ-emitters as it can inflict greater biological damage. By applying known bioconcentration factors of Cs in biota, measured biota concentrations of Cs were also used to estimate Cs concentrations in coastal seawater to be in the range of 102-103 Bq m-3. These estimates show that, 3 months after the accident and maximal release of radioactive Cs, levels of Cs persisted in coastal waters, although at levels that were two orders of magnitude lower than at the time of release. These June coastal seawater Cs levels were four orders of magnitude above Cs concentrations off Japan prior to the Fukushima disaster.

Iron release from corroded iron pipes in drinking water distribution systems: effect of dissolved oxygen.

PubMed

Sarin, P; Snoeyink, V L; Bebee, J; Jim, K K; Beckett, M A; Kriven, W M; Clement, J A

2004-03-01

Iron release from corroded iron pipes is the principal cause of "colored water" problems in drinking water distribution systems. The corrosion scales present in corroded iron pipes restrict the flow of water, and can also deteriorate the water quality. This research was focused on understanding the effect of dissolved oxygen (DO), a key water quality parameter, on iron release from the old corroded iron pipes. Corrosion scales from 70-year-old galvanized iron pipe were characterized as porous deposits of Fe(III) phases (goethite (alpha-FeOOH), magnetite (Fe(3)O(4)), and maghemite (alpha-Fe(2)O(3))) with a shell-like, dense layer near the top of the scales. High concentrations of readily soluble Fe(II) content was present inside the scales. Iron release from these corroded pipes was investigated for both flow and stagnant water conditions. Our studies confirmed that iron was released to bulk water primarily in the ferrous form. When DO was present in water, higher amounts of iron release was observed during stagnation in comparison to flowing water conditions. Additionally, it was found that increasing the DO concentration in water during stagnation reduced the amount of iron release. Our studies substantiate that increasing the concentration of oxidants in water and maintaining flowing conditions can reduce the amount of iron release from corroded iron pipes. Based on our studies, it is proposed that iron is released from corroded iron pipes by dissolution of corrosion scales, and that the microstructure and composition of corrosion scales are important parameters that can influence the amount of iron released from such systems.

Estradiol coupling to human monocyte nitric oxide release is dependent on intracellular calcium transients: evidence for an estrogen surface receptor.

PubMed

Stefano, G B; Prevot, V; Beauvillain, J C; Fimiani, C; Welters, I; Cadet, P; Breton, C; Pestel, J; Salzet, M; Bilfinger, T V

1999-10-01

We tested the hypothesis that estrogen acutely stimulates constitutive NO synthase (cNOS) activity in human peripheral monocytes by acting on an estrogen surface receptor. NO release was measured in real time with an amperometric probe. 17beta-estradiol exposure to monocytes stimulated NO release within seconds in a concentration-dependent manner, whereas 17alpha-estradiol had no effect. 17beta-estradiol conjugated to BSA (E2-BSA) also stimulated NO release, suggesting mediation by a membrane surface receptor. Tamoxifen, an estrogen receptor inhibitor, antagonized the action of both 17beta-estradiol and E2-BSA, whereas ICI 182,780, a selective inhibitor of the nuclear estrogen receptor, had no effect. We further showed, using a dual emission microfluorometry in a calcium-free medium, that the 17beta-estradiol-stimulated release of monocyte NO was dependent on the initial stimulation of intracellular calcium transients in a tamoxifen-sensitive process. Leeching out the intracellular calcium stores abolished the effect of 17beta-estradiol on NO release. RT-PCR analysis of RNA obtained from the cells revealed a strong estrogen receptor-alpha amplification signal and a weak beta signal. Taken together, a physiological dose of estrogen acutely stimulates NO release from human monocytes via the activation of an estrogen surface receptor that is coupled to increases in intracellular calcium.

Chemical regeneration of emitter surface increases thermionic diode life

NASA Technical Reports Server (NTRS)

Breiteieser, R.

1966-01-01

Chemical regeneration of sublimated emitter electrode increases the operating efficiency and life of thermionic diodes. A gas which forms chemical compounds with the sublimated emitter material is introduced into the space between the emitter and the collector. The compounds migrate to the emitter where they decompose and redeposit the emitter material.

Neutrophil-derived alpha defensins control inflammation by inhibiting macrophage mRNA translation

PubMed Central

Tomlinson, Gareth H.; Miles, Katherine; Smith, Richard W. P.; Rossi, Adriano G.; Hiemstra, Pieter S.; van ’t Wout, Emily F. A.; Dean, Jonathan L. E.; Gray, Nicola K.; Lu, Wuyuan; Gray, Mohini

2016-01-01

Neutrophils are the first and most numerous cells to arrive at the site of an inflammatory insult and are among the first to die. We previously reported that alpha defensins, released from apoptotic human neutrophils, augmented the antimicrobial capacity of macrophages while also inhibiting the biosynthesis of proinflammatory cytokines. In vivo, alpha defensin administration protected mice from inflammation, induced by thioglychollate-induced peritonitis or following infection with Salmonella enterica serovar Typhimurium. We have now dissected the antiinflammatory mechanism of action of the most abundant neutrophil alpha defensin, Human Neutrophil Peptide 1 (HNP1). Herein we show that HNP1 enters macrophages and inhibits protein translation without inducing the unfolded-protein response or affecting mRNA stability. In a cell-free in vitro translation system, HNP1 powerfully inhibited both cap-dependent and cap-independent mRNA translation while maintaining mRNA polysomal association. This is, to our knowledge, the first demonstration of a peptide released from one cell type (neutrophils) directly regulating mRNA translation in another (macrophages). By preventing protein translation, HNP1 functions as a “molecular brake” on macrophage-driven inflammation, ensuring both pathogen clearance and the resolution of inflammation with minimal bystander tissue damage. PMID:27044108

Throw Away Your Mathematical Handbook! Undergraduate Physics with Wolfram|Alpha, a FREE(!) Internet-Based Mathematical Engine

NASA Astrophysics Data System (ADS)

Looney, Craig W.

2009-10-01

Wolfram|Alpha (http://www.wolframalpha.com/), a free internet-based mathematical engine released earlier this year, represents an orders-of magnitude advance in mathematical power freely available - without money, passwords, or downloads - on the web. Wolfram|Alpha is based on Mathematica, so it can plot functions, take derivatives, solve systems of equations, perform symbolic and numerical integration, and more. These capabilities (especially plotting and integration) will be explored in the context of topics covered in upper level undergraduate physics courses.

Preparation of alpha-cyclodextrin-terminated polyrotaxane consisting of beta-cyclodextrins and pluronic as a building block of a biodegradable network.

PubMed

Ooya, Tooru; Ito, Akihiro; Yui, Nobuhiko

2005-05-23

A beta-CD-based biodegradable polyrotaxane was prepared by capping both terminals of polypseudorotaxane consisting of hydrazide-terminated PEG-block-PPG-block-PEG (Pluronic P-105) and beta-CD-succinates with mono-aldehyde alpha-CDs. By decreasing pH, the fluorescent intensity of TNS was increased with time, indicating cleavage of the terminal hydrazone bonds followed by beta-CD-succinate release. The terminal alpha-CD moieties of the polyrotaxane are useful for self-assembled formation with some guest molecules. [Diagram: see text

The P2Y(1) and P2Y(12) receptors mediate autoinhibition of transmitter release in sympathetic innervated tissues.

PubMed

Quintas, Clara; Fraga, Sónia; Gonçalves, Jorge; Queiroz, Glória

2009-12-01

In the sympathetic nervous system, ATP is a co-transmitter and modulator of transmitter release, inhibiting noradrenaline release by acting on P2Y autoreceptors, but in peripheral tissues the subtypes involved have only scarcely been identified. We investigated the identity of the noradrenaline release-inhibiting P2Y subtypes in the epididymal portion of vas deferens and tail artery of the rat. The subtypes operating as autoreceptors, the signalling mechanism and cross-talk with alpha(2)-autoreceptors, was also investigated in the epididymal portion. In both tissues, the nucleotides 2-methylthioATP, 2-methylthioADP, ADP and ATP inhibited noradrenaline release up to 68%, with the following order of potency: 2-methylthioADP=2-methylthioATP>ADP=ATP in the epididymal portion and 2-methylthioADP=2-methylthioATP=ADP>ATP in the tail artery. The selective P2Y(1) antagonist 2'-deoxy-N(6)-methyladenosine 3',5'-bisphosphate (30microM) and the P2Y(12) antagonist 2,2-dimethyl-propionic acid 3-(2-chloro-6-methylaminopurin-9-yl)-2-(2,2-dimethyl-propionyloxymethyl)-propyl ester (30microM) increased noradrenaline release per se by 25+/-8% and 18+/-3%, respectively, in the epididymal portion but not in tail artery. Both antagonists attenuated the effect of nucleotides in the epididymal portion whereas in tail artery only the P2Y(1) antagonist was effective. The agonist of P2Y(1) and P2Y(12) receptors, 2-methylthioADP, caused an inhibition of noradrenaline release that was not prevented by inhibition of phospholipase C or protein kinase C but was abolished by pertussis toxin. 2-methylthioADP and the adenosine A(1) receptor agonist N(6)-cyclopentyladenosine were less potent at inhibiting noradrenaline release under marked influence of alpha(2)-autoinhibition. In both tissues, nucleotides modulate noradrenaline release by activation of inhibitory P2Y(1) receptors but in the epididymal portion P2Y(12) receptors also participate. P2Y(1) and P2Y(12) receptors are coupled to G(i/o)-proteins and operate as autoreceptors in the vas deferens where they interact with alpha(2)-adrenoceptors on the modulation of noradrenaline release.

Fuel-induced amplification of insulin secretion in mouse pancreatic islets exposed to a high sulfonylurea concentration: role of the NADPH/NADP+ ratio.

PubMed

Panten, U; Rustenbeck, I

2008-01-01

The aim of this study was to examine whether the cytosolic NADPH/NADP+ ratio of beta cells serves as an amplifying signal in fuel-induced insulin secretion and whether such a function is mediated by cytosolic alpha-ketoglutarate. Pancreatic islets and islet cells were isolated from albino mice by collagenase digestion. Insulin secretion of incubated or perifused islets was measured by ELISA. The NADPH and NADP+ content of incubated islets was determined by enzymatic cycling. The cytosolic Ca2+ concentration ([Ca2+]c) in islets was measured by microfluorimetry and the activity of ATP-sensitive K+ channels in islet cells by patch-clamping. Both 30 mmol/l glucose and 10 mmol/l alpha-ketoisocaproate stimulated insulin secretion and elevated the NADPH/NADP+ ratio of islets preincubated in the absence of fuel. The increase in the NADPH/NADP+ ratio was abolished in the presence of 2.7 micromol/l glipizide (closing all ATP-sensitive K+ channels). However, alpha-ketoisocaproate, but not glucose, still stimulated insulin secretion. That glipizide did not inhibit alpha-ketoisocaproate-induced insulin secretion was not the result of elevated [Ca2+]c, as glucose caused a more marked [Ca2+]c increase. Insulin release triggered by glipizide alone was moderately amplified by dimethyl alpha-ketoglutarate (which is cleaved to produce cytosolic alpha-ketoglutarate), but there was no indication of a signal function of cytosolic alpha-ketoglutarate. The results strongly suggest that the NADPH/NADP+ ratio in the beta cell cytosol does not serve as an amplifying signal in fuel-induced insulin release. The study supports the view that amplification results from the intramitochondrial production of citrate by citrate synthase and from the associated export of citrate into the cytosol.

Use of probabilistic neural networks for emitter correlation

NASA Astrophysics Data System (ADS)

Maloney, P. S.

1990-08-01

The Probabilistic Neural Network (PNN) as described by Specht''3 has been successfully applied to a number of emitter correlation problems involving operational data for training and testing of the neural net work. The PNN has been found to be a reliable classification tool for determining emitter type or even identifying specific emitter platforms given appropriate representative data sets for training con sisting only of parametric data from electronic intelligence (ELINT) reports. Four separate feasibility studies have been conducted to prove the usefulness of PNN in this application area: . Hull-to-emitter correlation (HULTEC) for identification of seagoing emitter platforms . Identification of landbased emitters from airborne sensors . Pulse sorting according to emitter of origin . Emitter typing based on a dynamically learning neural network. 1 .

[Efficiencies of contamination source for flooring and some materials used in unencapsulated radioactivity handling facilities].

PubMed

Yoshida, M; Yoshizawa, M; Minami, K

1990-09-01

The efficiencies of contamination source, defined in ISO Report 7506-1, were experimentally determined for such materials as flooring, polyethylene, smear-tested filter paper and stainless steel plate. 5 nuclides of 147Pm, 60Co, 137Cs, 204Tl and 90Sr-Y were used to study beta-ray energy dependence of the efficiency, and 241Am as alpha-ray emitter. The charge-up effect in the measurement by a window-less 2 pi-proportional counter was evaluated to obtain reliable surface emission rate. The measured efficiencies for non-permeable materials, except for two cases, are more than 0.5 even for 147Pm. The ISO recommendations were shown to be conservative enough on the basis of present results.

Thorium-232 fission induced by light charged particles up to 70 MeV

NASA Astrophysics Data System (ADS)

Métivier, Vincent; Duchemin, Charlotte; Guertin, Arnaud; Michel, Nathalie; Haddad, Férid

2017-09-01

Studies have been devoted to the production of alpha emitters for medical application in collaboration with the GIP ARRONAX that possesses a high energy and high intensity multi-particle cyclotron. The productions of Ra-223, Ac-225 and U-230 have been investigated from the Th-232(p,x) and Th-232(d,x) reactions using the stacked-foils method and gamma spectrometry measurements. These reactions have led to the production of several fission products, including some with a medical interest like Mo-99, Cd-115g and I-131. This article presents cross section data of fission products obtained from these undedicated experiments. These data have been also compared with the TALYS code results.

High temperature bias line stabilized current sources

DOEpatents

Patterson, III, Raymond B.

1984-01-01

A compensation device for the base of emitter follower configured bipolar transistors becoming operable at elevated temperatures including a bipolar transistor of a geometry of not more than half the geometry of the bipolar emitter follower having its collector connected to the base of the emitter follower and its base and emitter connected together and to the emitter of the emitter follower.

High temperature bias line stabilized current sources

DOEpatents

Patterson, R.B. III.

1984-09-11

A compensation device for the base of emitter follower configured bipolar transistors becoming operable at elevated temperatures including a bipolar transistor of a geometry of not more than half the geometry of the bipolar emitter follower having its collector connected to the base of the emitter follower and its base and emitter connected together and to the emitter of the emitter follower. 1 fig.

Pyridostigmine bromide modulates topical irritant-induced cytokine release from human epidermal keratinocytes and isolated perfused porcine skin.

PubMed

Monteiro-Riviere, Nancy A; Baynes, Ronald E; Riviere, Jim E

2003-02-01

Gulf War personnel were given pyridostigmine bromide (PB) as a prophylactic treatment against organophosphate nerve agent exposure, and were exposed to the insecticide permethrin and the insect repellent N,N-diethyl-m-toluamide (DEET). The purpose of this study was to assess the effects of PB to modulate release of inflammatory biomarkers after topical chemical exposure to chemical mixtures containing permethrin and DEET applied in ethanol or water vehicles. Treatments were topically applied to isolated perfused porcine skin flaps (IPPSFs). Concentrations of interleukin-8 (IL-8), tumor necrosis factor-alpha (TNF-alpha) and prostaglandin E(2) (PGE(2)) were assayed in perfusate to probe for potential inflammatory effects after complex mixture application. IPPSFs (n=4/treatment) were topically dosed with mixtures of permethrin, DEET, and permethrin/DEET, in ethanol. Each treatment was repeated with perfusate spiked with 50 ng/ml of PB. Perfusate was also spiked with 30 ng/ml diisopropylfluorophosphate to simulate low level organophosphate nerve agent exposure. Timed IPPSF venous effluent samples (0.5,1,2,4, and 8 h) were assayed by ELISA for IL-8 and TNF-alpha and by EIA for PGE(2). Overall, PB infusion caused a decrease or IL-8 and PGE(2) release. Effects on TNF-alpha were vehicle dependent. To probe the potential mechanism of this PB effect, human epidermal keratinocyte HEK cell cultures were exposed to permethrin DEET permethrin/DEET, with and without PB in DMSO. IL-8 was assayed at 1, 2, 4, 8, 12 and 24 h. PB suppressed IL-8 in permethrin and ethanol treatment from 4 to 24 h confirming the IPPSF results. In conclusion, these studies suggest that systemic exposure to PB suppressed IL-8 release at multiple time points in two skin model systems. This interaction merits further study.

Modulation of the release of ( sup 3 H)norepinephrine from the base and body of the rat urinary bladder by endogenous adrenergic and cholinergic mechanisms

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

Somogyi, G.T.; de Groat, W.C.

Modulation of (3H)NE release was studied in rat urinary bladder strips prelabeled with (3H)NE. (3H)NE uptake occurred in strips from the bladder base and body, but was very prominent in the base where the noradrenergic innervation is most dense. Electrical field stimulation markedly increased (3H)NE outflow from the superfused tissue. The quantity of (3H)NE release was approximately equal during three consecutive periods of stimulation. Activation of presynaptic muscarinic receptors by 1.0 microM oxotremorine reduced (3H)NE release to 46% of the control. Atropine (1 microM) blocked the effect of oxotremorine and increased the release to 147% of predrug control levels. Activationmore » of presynaptic alpha-2 adrenoceptors by 1 microM clonidine reduced (3H)NE release to 55% of control. Yohimbine blocked the action of clonidine and increased the release to 148% of control. The release of (3H)NE from the bladder base and body was increased by both 1 microM atropine (to 167% and 174% of control, respectively) and 1 microM yohimbine (to 286% and 425% of control, respectively). Atropine and yohimbine administered in combination had similar facilitatory effects as when administered alone. We conclude that the release of (3H)NE from adrenergic nerve endings in electrically stimulated bladder strips is modulated via endogenous transmitters acting on both muscarinic and alpha-2 adrenergic presynaptic receptors and that the latter provide the most prominent control.« less

Emitter location errors in electronic recognition system

NASA Astrophysics Data System (ADS)

Matuszewski, Jan; Dikta, Anna

2017-04-01

The paper describes some of the problems associated with emitter location calculations. This aspect is the most important part of the series of tasks in the electronic recognition systems. The basic tasks include: detection of emission of electromagnetic signals, tracking (determining the direction of emitter sources), signal analysis in order to classify different emitter types and the identification of the sources of emission of the same type. The paper presents a brief description of the main methods of emitter localization and the basic mathematical formulae for calculating their location. The errors' estimation has been made to determine the emitter location for three different methods and different scenarios of emitters and direction finding (DF) sensors deployment in the electromagnetic environment. The emitter has been established using a special computer program. On the basis of extensive numerical calculations, the evaluation of precise emitter location in the recognition systems for different configuration alignment of bearing devices and emitter was conducted. The calculations which have been made based on the simulated data for different methods of location are presented in the figures and respective tables. The obtained results demonstrate that calculation of the precise emitter location depends on: the number of DF sensors, the distances between emitter and DF sensors, their mutual location in the reconnaissance area and bearing errors. The precise emitter location varies depending on the number of obtained bearings. The higher the number of bearings, the better the accuracy of calculated emitter location in spite of relatively high bearing errors for each DF sensor.

Methane emission estimates using chamber and tracer release experiments for a municipal waste water treatment plant

NASA Astrophysics Data System (ADS)

Yver-Kwok, C. E.; Müller, D.; Caldow, C.; Lebègue, B.; Mønster, J. G.; Rella, C. W.; Scheutz, C.; Schmidt, M.; Ramonet, M.; Warneke, T.; Broquet, G.; Ciais, P.

2015-03-01

This study presents two methods for estimating methane emissions from a waste water treatment plant (WWTP) along with results from a measurement campaign at a WWTP in Valence, France. These methods, chamber measurements and tracer release, rely on Fourier Transform Infrared (FTIR) spectroscopy and Cavity Ring Down Spectroscopy (CRDS) instruments. We show that the tracer release method is suitable to quantify facility- and some process-scale emissions, while the chamber measurements, provide insight into individual process emissions. Uncertainties for the two methods are described and discussed. Applying the methods to CH4 emissions of the WWTP, we confirm that the open basins are not a major source of CH4 on the WWTP (about 10% of the total emissions), but that the pretreatment and sludge treatment are the main emitters. Overall, the waste water treatment plant represents a small part (about 1.5%) of the methane emissions of the city of Valence and its surroundings, which is lower than the national inventories.

Effects of TNF-alpha on Endothelial Cell Collective Migration

NASA Astrophysics Data System (ADS)

Chen, Desu; Wu, Di; Helim Aranda-Espinoza, Jose; Losert, Wolfgang

2013-03-01

Tumor necrosis factor (TNF-alpha) is a small cell-signaling protein usually released by monocytes and macrophages during an inflammatory response. Previous work had shown the effects of TNF-alpha on single cell morphology, migration, and biomechanical properties. However, the effect on collective migrations remains unexplored. In this work, we have created scratches on monolayers of human umbilical endothelial cells (HUVECs) treated with 25ng/mL TNF-alpha on glass substrates. The wound healing like processes were imaged with phase contrast microscopy. Quantitative analysis of the collective migration of cells treated with TNF-alpha indicates that these cells maintain their persistent motion and alignment better than untreated cells. In addition, the collective migration was characterized by measuring the amount of non-affine deformations of the wound healing monolayer. We found a lower mean non-affinity and narrower distribution of non-affinities upon TNF-alpha stimulation. These results suggest that TNF-alpha introduces a higher degree of organized cell collective migration.

Involvement of central, but not placental corticotropin releasing hormone (CRH) in heat stress induced immunosuppression during pregnancy.

PubMed

Nakamura, H; Nagase, H; Ogino, K; Hatta, K; Matsuzaki, I

2001-03-01

To clarify whether corticotropin releasing hormone (CRH) and beta-endorphin (betaEP) system mediate maternal immunosuppression in pregnant rats exposed to heat through central or placental pathway, we examined the effects of intravenous (iv) (100 or 500 microg) or intracerebroventricular (icv) (5 microg) administration of CRH receptor antagonist alpha-helical CRH (9-41) on splenic natural killer cell activity (NKCA) as well as betaEP in blood, pituitary lobes, and placenta in pregnant rats at 15 to 16 days gestation. Two-way ANOVA revealed that heat reduced NKCA and elevated blood and pituitary betaEP but did not change placental betaEP. Iv administered 500 microg and icv administered alpha-helical CRH reversed the reduced NKCA and the elevated pituitary betaEP, while iv administration of 100 microg alpha-helical CRH did not. The increased blood betaEP was reversed by iv 100 and 500 microg alpha-helical CRH and icv administration. Both iv and icv administrations reduced placental betaEP independent of heat exposure. Thus, the response of placental betaEP to iv administration of alpha-helical CRH seemed to be stronger than that of pituitary betaEP. These results indicate that alpha-helical CRH which acts on pituitary betaEP antagonizes heat-induced immunosuppression during pregnancy, suggesting that immunosuppression produced by heat stress during pregnancy is mediated by the central CRH system. The placental CRH-betaEP system seems unlikely to be involved in the immunosuppression. Physiologic roles of placental CRH and opioid system should be clarified by future in vitro experiments using placenta specimen including placental immunocyte.

Clebopride enhances contractility of the guinea pig stomach by blocking peripheral D2 dopamine receptor and alpha-2 adrenoceptor.

PubMed

Takeda, K; Taniyama, K; Kuno, T; Sano, I; Ishikawa, T; Ohmura, I; Tanaka, C

1991-05-01

The mechanism of action of clebopride on the motility of guinea pig stomach was examined by the receptor binding assay for bovine brain membrane and by measuring gastric contractility and the release of acetylcholine from the stomach. The receptor binding assay revealed that clebopride bound to the D2 dopamine receptor with a high affinity and to the alpha-2 adrenoceptor and 5-HT2 serotonin receptor with relatively lower affinity, and not to D1 dopamine, alpha-1 adrenergic, muscarinic acetylcholine, H1 histamine, or opioid receptor. In strips of the stomach, clebopride at 10(-8) M to 10(-5) M enhanced the electrical transmural stimulation-evoked contraction and the release of acetylcholine. This enhancement was attributed to the blockade of the D2 dopamine receptor and alpha-2 adrenoceptor because: 1) Maximum responses obtained with specific D2 dopamine receptor antagonist, domperidone, and with specific alpha-2 adrenoceptor antagonist, yohimbine, were smaller than that with clebopride, and the sum of the effects of these two specific receptor antagonists is approximately equal to the effect of clebopride. 2) The facilitatory effect of clebopride was partially eliminated by pretreatment of the sample with domperidone or yohimbine, and the facilitatory effect of clebopride was not observed in preparations treated with the combination of domperidone and yohimbine. Clebopride also antagonized the inhibitory effects of dopamine and clonidine on the electrical transmural stimulation-evoked responses. These results indicate that clebopride acts on post ganglionic cholinergic neurons at D2 and alpha-2 receptors in this preparation to enhance enteric nervous system stimulated motility.

Improving the Sensitivity of Mass Spectrometry by Using a New Sheath Flow Electrospray Emitter Array at Subambient Pressures

DOE PAGES

Cox, Jonathan T.; Marginean, Ioan; Kelly, Ryan T.; ...

2014-03-28

Arrays of chemically etched emitters with individualized sheath gas capillaries have been developed to enhance electrospray ionization (ESI) at subambient pressures. By including an emitter array in a subambient pressure ionization with nanoelectrospray (SPIN) source, ionization and transmission efficiency can be maximized allowing for increased sensitivity in mass spectrometric analyses. The SPIN source eliminates the major ion losses at conventional ESI-mass spectrometry (MS) interface by placing the emitter in the first vacuum region of the instrument. To facilitate stable electrospray currents in such conditions we have developed an improved emitter array with individualized sheath gas around each emitter. The utilitymore » of the new emitter arrays for generating stable multi-electrosprays at subambient pressures was probed by coupling the emitter array/SPIN source with a time of flight (TOF) mass spectrometer. The instrument sensitivity was compared between single emitter/SPIN-MS and multi-emitter/SPIN-MS configurations using an equimolar solution of 9 peptides. An increase in sensitivity correlative to the number of emitters in the array was observed.« less

Rare earth garnet selective emitter

NASA Technical Reports Server (NTRS)

Lowe, Roland A.; Chubb, Donald L.; Farmer, Serene C.; Good, Brian S.

1994-01-01

Thin film Ho-YAG and Er-YAG emitters with a platinum substrate exhibit high spectral emittance in the emission band (epsilon(sub lambda) approximately equal to 0.74, ((4)l(sub 15/2)) - ( (4)l(sub13/2)), for Er-YAG and epsilon(sub lambda) approximately equal to 0.65, ((5)l(sub 7))-((5)l(sub 8)) for Ho-YAG) at excellent candidates for high efficiency selective emitters in the thermophotovoltaics (TPV) systems operating at moderate temperatures (1200-1500K). Spectral emittance measurements of the thin films were made (1.2 less than lambda less than 3.0 microns) and compared to the theoretical emittances calculated using measured values of the spectral extinction coefficient. In this paper we present the results for a new class of rare earth ion selective emitters. These emitters are thin sections (less than 1 mm) of yttrium aluminum garnet (YAG) single crystal with a rare earth substitutional impurity. This paper presents normal spectral emittance, epsilon(sub lambda), measurements of holmium (Ho), and erbium (Er) doped YAG thin film selective emitters at 1500 K, and compares those results with the theoretical spectral emittance.

Improving the Sensitivity of Mass Spectrometry by Using a New Sheath Flow Electrospray Emitter Array at Subambient Pressures

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

Cox, Jonathan T.; Marginean, Ioan; Kelly, Ryan T.

Arrays of chemically etched emitters with individualized sheath gas capillaries have been developed to enhance electrospray ionization (ESI) at subambient pressures. By including an emitter array in a subambient pressure ionization with nanoelectrospray (SPIN) source, ionization and transmission efficiency can be maximized allowing for increased sensitivity in mass spectrometric analyses. The SPIN source eliminates the major ion losses at conventional ESI-mass spectrometry (MS) interface by placing the emitter in the first vacuum region of the instrument. To facilitate stable electrospray currents in such conditions we have developed an improved emitter array with individualized sheath gas around each emitter. The utilitymore » of the new emitter arrays for generating stable multi-electrosprays at subambient pressures was probed by coupling the emitter array/SPIN source with a time of flight (TOF) mass spectrometer. The instrument sensitivity was compared between single emitter/SPIN-MS and multi-emitter/SPIN-MS configurations using an equimolar solution of 9 peptides. An increase in sensitivity correlative to the number of emitters in the array was observed.« less

Determination of the efficiency of commercially available dose calibrators for beta-emitters.

PubMed

Valley, Jean-François; Bulling, Shelley; Leresche, Michel; Wastiel, Claude

2003-03-01

The goals of this investigation are to determine whether commercially available dose calibrators can be used to measure the activity of beta-emitting radionuclides used in pain palliation and to establish whether manufacturer-supplied calibration factors are appropriate for this purpose. Six types of commercially available dose calibrators were studied. Dose calibrator response was controlled for 5 gamma-emitters used for calibration or typically encountered in routine use. For the 4 most commonly used beta-emitters ((32)P, (90)Sr, (90)Y, and (169)Er) dose calibrator efficiency was determined in the syringe geometry used for clinical applications. Efficiency of the calibrators was also measured for (153)Sm and (186)Re, 2 beta-emitters with significant gamma-contributions. Source activities were traceable to national standards. All calibrators measured gamma-emitters with a precision of +/-10%, in compliance with Swiss regulatory requirements. For beta-emitters, dose calibrator intrinsic efficiency depends strongly on the maximal energy of the beta-spectrum and is notably low for (169)Er. Manufacturer-supplied calibration factors give accurate results for beta-emitters with maximal beta-energy in the middle-energy range (1 MeV) but are not appropriate for use with low-energy ((169)Er) or high-energy ((90)Y) beta-emitters. beta-emitters with significant gamma-contributions behave like gamma-emitters. Commercially available dose calibrators have an intrinsic efficiency that is sufficient for the measurement of beta-emitters, including beta-emitters with a low maximum beta-energy. Manufacturer-supplied calibration factors are reliable for gamma-emitters and beta-emitters in the middle-energy range. For low- and high-energy beta-emitters, the use of manufacturer-supplied calibration factors introduces significant measurement inaccuracy.

Characterization of histamine-releasing activity: role of cytokines and IgE heterogeneity.

PubMed

Liao, T N; Hsieh, K H

1992-07-01

Histamine-releasing factors (HRFs) are a group of cytokines that cause histamine release (HR) from basophils and mast cells. The concept of the priming effect of cytokines and the heterogeneity of IgE involved in the HRF-induced HR have been emphasized in recent years. In this study, we performed a series of experiments to elucidate the above-mentioned hypotheses. The stock HRF were obtained by stimulating mononuclear cells (MNC) with phytohemagglutinin (PHA). Maximal activity was observed 36 hr after culture. By gel filtration, HRF was eluted with a peak activity ranging from 12 to 18 KD. A large portion (75%) of HRF activity could be neutralized by a combination of antibodies against interleukin 1 (IL-1), IL-3, IL-8, granulocyte-macrophage colony-stimulating factor (GM-CSF), and tumor necrosis factor-alpha (TNF-alpha). The stimulation of basophils with 100 ng/ml each of IL-3, IL-6, IL-7, GM-CSF, or TNF-alpha alone caused 10% HR; however, when the cells were pretreated with 10 ng/ml of either IL-3, IL-6, IL-7, IL-8, TNF-alpha, or GM-CSF and then stimulated with anti-IgE, a marked increase in HR was regularly observed. The combination of 100 ng/ml each of IL-1, IL-3, IL-8, GM-CSF, and TNF-alpha could induce only about 20% HR; furthermore, such combinations did not have an additive or synergistic priming effect on anti-IgE-induced HR compared to the effect of single cytokines. Stripping of surface-bound IgE with lactic acid markedly reduced the capacity of basophils to release histamine in response to MNC-HRF and anti-IgE. Passive sensitization of IgE-stripped basophils with high-HRF responders' serum could restore their responsiveness to both MNC-HRF and anti-IgE, but passive sensitization with low-HRF responders' serum could restore responsiveness to anti-IgE only. Moreover, passage of MNC-HRF through high-, but not low-HRF, responders' IgE-Sepharose columns significantly reduced the HR activity of MNC-HRF. Finally, although the eluant could induce only 10% HR, the majority of its HR activity could be restored by the addition of effluent but not by the mixture of IL-1, IL-3, IL-8, GM-CSF, and TNF-alpha, suggesting the presence of a complex interaction among those cytokines. In summary, MNC-HRF contained at least two types of HRF activity; one was IgE dependent and the other was IgE independent.(ABSTRACT TRUNCATED AT 400 WORDS)

Multinozzle emitter arrays for ultrahigh-throughput nanoelectrospray mass spectrometry

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

Wang, Daojing; Mao, Pan; Wang, Hung-Ta

The present invention provides for a structure comprising a plurality of emitters, wherein a first nozzle of a first emitter and a second nozzle of a second emitter emit in two directions that are not or essentially not in the same direction; wherein the walls of the nozzles and the emitters form a monolithic whole. The present invention also provides for a structure comprising an emitter with a sharpened end from which the emitter emits; wherein the emitters forms a monolithic whole. The present invention also provides for a fully integrated separation of proteins and small molecules on a siliconmore » chip before the electrospray mass spectrometry analysis.« less

Alpha Channeling in Open-System Magnetic Devices

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

Fisch, Nathaniel

The Grant DE-SC0000736, Alpha Channeling in Open-System Magnetic Devices, is a continuation of the Grant DE-FG02-06ER54851, Alpha Channeling in Mirror Machines. In publications funded by DE-SC0000736, the grant DE-FG02-06ER54851 was actually credited. The key results obtained under Grant DE-SC0000736, Alpha Channeling in Open-System Magnetic Devices, appear in a series of publications. The earlier effort under DE-FG02- 06ER54851 was the subject of a previous Final Report. The theme of this later effort has been unusual confinement effects, or de-confinement effects, in open-field magnetic confinement devices. First, the possibilities in losing axisymmetry were explored. Then a number of issues in rotating plasmamore » were addressed. Most importantly, a spinoff application to plasma separations was recognized, which also resulted in a provisional patent application. (That provisional patent application, however, was not pursued further.) Alpha channeling entails injecting waves into magnetically confined plasma to release energy from one particular ion while ejecting that ion. The ejection of the ion is actually a concomitant effect in releasing energy from the ion to the wave. In rotating plasma, there is the opportunity to store the energy in a radial electric field rather than in waves. In other words, the ejected alpha particle loses its energy to the radial potential, which in turn produces plasma rotation. This is a very useful effect, since producing radial electric fields by other means are technologically more difficult. In fact, one can heat ions, and then eject them, to produce the desired radial field. In each case, there is a separation effect of different ions, which generalizes the original alpha-channeling concept of separating alpha ash from hydrogen. In a further generalization of the separation concept, a double-well filter represents a new way to produce high-throughput separations of ions, potentially useful for nuclear waste remediation.« less

Parallel nanomanufacturing via electrohydrodynamic jetting from microfabricated externally-fed emitter arrays

NASA Astrophysics Data System (ADS)

Ponce de Leon, Philip J.; Hill, Frances A.; Heubel, Eric V.; Velásquez-García, Luis F.

2015-06-01

We report the design, fabrication, and characterization of planar arrays of externally-fed silicon electrospinning emitters for high-throughput generation of polymer nanofibers. Arrays with as many as 225 emitters and with emitter density as large as 100 emitters cm-2 were characterized using a solution of dissolved PEO in water and ethanol. Devices with emitter density as high as 25 emitters cm-2 deposit uniform imprints comprising fibers with diameters on the order of a few hundred nanometers. Mass flux rates as high as 417 g hr-1 m-2 were measured, i.e., four times the reported production rate of the leading commercial free-surface electrospinning sources. Throughput increases with increasing array size at constant emitter density, suggesting the design can be scaled up with no loss of productivity. Devices with emitter density equal to 100 emitters cm-2 fail to generate fibers but uniformly generate electrosprayed droplets. For the arrays tested, the largest measured mass flux resulted from arrays with larger emitter separation operating at larger bias voltages, indicating the strong influence of electrical field enhancement on the performance of the devices. Incorporation of a ground electrode surrounding the array tips helps equalize the emitter field enhancement across the array as well as control the spread of the imprints over larger distances.

Dual inhibitory action of enadoline (CI977) on release of amino acids in the rat hippocampus.

PubMed

Millan, M H; Chapman, A G; Meldrum, B S

1995-06-06

The effect of the kappa-opioid receptor agonist enadoline (CI977, (5R)-(5 alpha,7 alpha,8 beta)-N-methyl-N-[7-(1-pyrrilidinyl)-1-oxaspiro [4,5]dec-8-yl-4-benzofuranacetamide monohydrochloride), on the release of amino acids was studied in the hippocampus of freely moving rats. K+, 100 mM, or veratrine, 100 microM, were applied for 10 min via the dialysis probe, either alone (control groups) or together with CI977 (after a 10 min pretreatment with CI977 in the perfusion medium). To test the specificity of the response to CI977, nor-binaltorphimine, a selective kappa-opioid receptor antagonist, was delivered together with CI977 in two groups of animals. To test the effect of systemic injection, CI977 was given subcutaneously 30 min prior to either stimulus. K(+)-induced release of glutamate and aspartate was significantly reduced by CI977, 2.5 mM; release of gamma-aminobutyric acid (GABA) was reduced by 250 microM CI977 in the probe. The effect of CI977 on release of glutamate and aspartate, but not of GABA, was reversed by nor-binaltorphimine (45 microM). Systemic treatment with CI977, 1 or 10 mg/kg, did not reduce K(+)-induced release of glutamate. Veratrine-induced release of aspartate and glutamate was significantly inhibited by 25 microM and release of GABA by 250 microM CI977 in the probe, and this effect was not modified by nor-binaltorphimine (58 microM). Systemic injection of CI977 1 mg/kg significantly reduced veratrine-induced release of glutamate. These results indicate that CI977 regulates release of amino acids by two independent mechanisms.(ABSTRACT TRUNCATED AT 250 WORDS)

Single-stage plasma-based correlated energy spread compensation for ultrahigh 6D brightness electron beams

DOE PAGES

Manahan, Grace G.; Habib, A. F.; Scherkl, P.; ...

2017-06-05

Plasma photocathode wakefield acceleration combines energy gains of tens of GeV m –1 with generation of ultralow emittance electron bunches, and opens a path towards 5D-brightness orders of magnitude larger than state-of-the-art. This holds great promise for compact accelerator building blocks and advanced light sources. However, an intrinsic by-product of the enormous electric field gradients inherent to plasma accelerators is substantial correlated energy spread—an obstacle for key applications such as free-electron-lasers. Here we show that by releasing an additional tailored escort electron beam at a later phase of the acceleration, when the witness bunch is relativistically stable, the plasma wavemore » can be locally overloaded without compromising the witness bunch normalized emittance. Here, this reverses the effective accelerating gradient, and counter-rotates the accumulated negative longitudinal phase space chirp of the witness bunch. Thereby, the energy spread is reduced by an order of magnitude, thus enabling the production of ultrahigh 6D-brightness beams.« less

Effect of salivary gland adenocarcinoma cell-derived alpha-N-acetylgalactosaminidase on the bioactivity of macrophage activating factor.

PubMed

Matsuura, Takashi; Uematsu, Takashi; Yamaoka, Minoru; Furusawa, Kiyofumi

2004-03-01

The aim of this study was to clarify the effects of alpha-N-acetylgalactosaminidase (alpha-NaGalase) produced by human salivary gland adenocarcinoma (SGA) cells on the bioactivity of macrophage-activating factor (GcMAF). High exo-alpha-NaGalase activity was detected in the SGA cell line HSG. HSG alpha-NaGalase had both exo- and endo-enzyme activities, cleaving the Gal-GalNAc and GalNAc residues linked to Thr/Ser but not releasing the [NeuAc2-6]GalNac residue. Furthermore, GcMAF enzymatically prepared from the Gc protein enhanced the superoxide-generation capacity and phagocytic activity of monocytes/macrophages. However, GcMAF treated with purified alpha-NaGalase did not exhibit these effects. Thus, HSG possesses the capacity to produce larger quantities of alpha-NaGalase, which inactivates GcMAF produced from Gc protein, resulting in reduced phagocytic activity and superoxide-generation capacity of monocytes/macrophages. The present data strongly suggest that HSG alpha-NaGalase acts as an immunodeficiency factor in cancer patients.

Acidic attack of perfluorinated alkyl ether lubricant molecules by metal oxide surfaces

NASA Technical Reports Server (NTRS)

Zehe, Michael J.; Faut, Owen D.

1990-01-01

The reactions of linear perfluoropolyalkylether (PFAE) lubricants with alpha-Fe203 and Fe203-based solid superacids were studied. The reaction with alpha-Fe203 proceeds in two stages. The first stage is an initial slow catalytic decomposition of the fluid. This reaction releases reactive gaseous products which attach the metal oxide and convert it to FeF3. The second stage is a more rapid decomposition of the fluid, effected by the surface FeF3. A study of the initial breakdown step was performed using alpha-Fe203, alpha-Fe203 preconverted to FeF3, and sulfate-promoted alpha-Fe203 superacids. The results indicate that the breakdown reaction involves acidic attack at fluorine atoms on acetal carbons in the linear PFAE. Possible approaches to combat the problem are outlined.

Effects of Extended-Release Guanfacine on ADHD Symptoms and Sedation-Related Adverse Events in Children with ADHD

ERIC Educational Resources Information Center

Faraone, Stephen V.; Glatt, Stephen J.

2010-01-01

Objective: Guanfacine extended release (GXR) is a selective alpha[subscript 2A]-adrenoceptor agonist that is shown to be an effective nonstimulant treatment for the symptoms of attention-deficit/hyperactivity disorder. This report documents the time course and predictors of symptom efficacy and sedation-related adverse events (AEs) that emerge…

Chemical evolution. XXI - The amino acids released on hydrolysis of HCN oligomers

NASA Technical Reports Server (NTRS)

Ferris, J. P.; Wos, J. D.; Nooner, D. W.; Oro, J.

1974-01-01

Major amino acids released by hydrolysis of acidic and basic HCN oligomers are identified by chromatography as Gly, Asp, and diaminosuccinic acid. Smaller amounts of Ala, Ile and alpha-aminoisobutyric acid are also detected. The amino acids released did not change appreciably when the hydrolysis medium was changed from neutral to acidic or basic. The presence of both meso and d, l-diaminosuccinic acids was established by paper chromatography and on an amino acid analyzer.

Evaluation of tumor necrosis factor-alpha (TNF) as an exposure or risk marker in three French coal mining regions.

PubMed

Porcher, J M; Oberson, D; Viseux, N; Sébastien, P; Honnons, S; Auburtin, G

1994-01-01

Several studies have shown the crucial role of the tumor necrosis factor-alpha (TNF) in the fibrosis induced by dusts containing silica and its role in the transition from simple pneumoconiosis (CWSP) to progressive massive fibrosis (PMF). To evaluate the nocivity of dust exposure among coal miners (n = 474) from different mining regions in France (e.g., Nord-Pas de Calais, Lorraine, and Provence), spontaneous and LPS or silica-induced TNF released by peripheral blood monocytes was quantified. The primary aim of this effort was to study the link between the prevalence of coal workers pneumoconiosis (CWP) and TNF release. TNF levels were significantly different between active miners from the three regions. However, after correction for age and region, TNF was found not to be related to dust exposure. Interestingly, a very low, homogeneous expression of TNF was observed in the group from Provence. These results are probably related to the absence of pneumoconiosis in this area. A positive relation between profusion and TNF release was found for all stimulants among retired miners with PMF. Although in retired miners TNF release was consistently higher, the design of the study does not allow this effect to be separated from that of age. Both silica and nonstimulated TNF release were found to increase with increasing radiological symptoms; the opposite was found for LPS-induced release.

A combined emitter threat assessment method based on ICW-RCM

NASA Astrophysics Data System (ADS)

Zhang, Ying; Wang, Hongwei; Guo, Xiaotao; Wang, Yubing

2017-08-01

Considering that the tradition al emitter threat assessment methods are difficult to intuitively reflect the degree of target threaten and the deficiency of real-time and complexity, on the basis of radar chart method(RCM), an algorithm of emitter combined threat assessment based on ICW-RCM (improved combination weighting method, ICW) is proposed. The coarse sorting is integrated with fine sorting in emitter combined threat assessment, sequencing the emitter threat level roughly accordance to radar operation mode, and reducing task priority of the low-threat emitter; On the basis of ICW-RCM, sequencing the same radar operation mode emitter roughly, finally, obtain the results of emitter threat assessment through coarse and fine sorting. Simulation analyses show the correctness and effectiveness of this algorithm. Comparing with classical method of emitter threat assessment based on CW-RCM, the algorithm is visual in image and can work quickly with lower complexity.

Prolonged survival in secondary glioblastoma following local injection of targeted alpha therapy with 213Bi-substance P analogue.

PubMed

Krolicki, Leszek; Bruchertseifer, Frank; Kunikowska, Jolanta; Koziara, Henryk; Królicki, Bartosz; Jakuciński, Maciej; Pawlak, Dariusz; Apostolidis, Christos; Mirzadeh, Saed; Rola, Rafał; Merlo, Adrian; Morgenstern, Alfred

2018-04-30

Glioblastoma multiforme (GBM), the most common malignant brain tumor, mainly manifests as a primary de novo and less frequently as a secondary glial neoplasm. GBM has been demonstrated to overexpress the NK-1 receptor and substance P can be used as a ligand for targeted therapy. Alpha emitters, e.g. 213 Bi, that deposit their high energy within a short range allow the selective irradiation of tumor cells while sparing adjacent neuronal structures. Among 50 glioma patients of different subtypes that have to date been treated with targeted alpha therapy at the Medical University Warsaw, we report here the data on nine patients with secondary GBM. Following surgery, chemo- and radiotherapy, recurrent GBM was treated by intracavitary injection of 1-6 doses of 0.9-2.3 GBq 213 Bi- DOTA-[Thi 8 ,Met(O 2 ) 11 ]-substance P ( 213 Bi-DOTA-SP) in 2-month intervals. 68 Ga-DOTA-[Thi 8 ,Met(O 2 ) 11 ]-substance P ( 68 Ga-DOTA-SP) was co-injected with the therapeutic doses to assess biodistribution using PET/CT. Therapeutic response was monitored with MRI. Treatment with activities ranging from 1.4 to 9.7 (median 5.8) GBq 213 Bi- DOTA-SP was well tolerated with only mild transient adverse reactions, mainly headaches due to a transient perfocal edema reaction. The median progression free survival and overall survival time following the initiation of alpha therapy was 5.8 and 16.4 months, respectively. The median overall survival time from the first diagnosis was 52.3 months. Two out of nine patients are still alive 39 and 51 months, respectively, after the initiation of the therapy. Targeted alpha therapy of secondary GBM with 213 Bi-DOTA-SP is safe and well tolerated and may evolve as a promising novel therapeutic option for secondary GBM.

Peritoneal macrophage and blood monocyte functions after open and laparoscopic-assisted cecectomy in rats.

PubMed

Lee, S W; Feingold, D L; Carter, J J; Zhai, C; Stapleton, G; Gleason, N; Whelan, R L

2003-12-01

It has been well established that open abdominal surgery results in systemic immunosuppression postoperatively; in contrast, laparoscopic surgery is associated with significantly better preserved systemic immune function. However, when intraperitoneal (local) immune function is considered, laparoscopic procedures done under a CO2 pneumoperitoneum (pneumo) have been shown to result in greater immunosuppression compared to that of open surgery. Few studies have simultaneously assessed systemic and local immune function. The purpose of this study was to assess peripheral blood mononuclear cell (PBMC) and peritoneal macrophage tumor necrosis factor-alpha (TNF-alpha) levels, H2O2 production, and MHC class II antigen expression after open and laparoscopically assisted cecectomy in a rat model. A total of 75 Sprague Dawley rats were used for three separate experiments. For each study, rats were randomly divided into three groups: anesthesia alone (AC), laparoscopic-assisted cecectomy (LC), and open cecectomy via full laparotomy (OP). A CO2 pneumo was used for laparoscopic operations. On postoperative day 1 the animals were sacrificed, macrophages were harvested via intraperitoneal lavage, and PBMCs were isolated from whole blood obtained by cardiac puncture. In experiment 1, macrophages and PBMC from each animal were stimulated with lipopolysaccharide, after which TNF-alpha levels of the supernatant were determined. In experiment 2, after stimulation with PMA, H2O2 release was assessed by measuring fluorescence. In experiment 3, via flow cytometry, the number of cells with surface MHC class II proteins were determined. Data from the three groups in each experiment were compared using analysis of variance Tukey-Kramer tests. Macrophages and PBMC from rats in the OP group released significantly more TNF-alpha than cells from rats in the LC ( p < 0.05) or AC ( p < 0.05) groups. Macrophages from rats in the OP group released significantly less H2O2 than cells from the AC ( p < 0.01) and LC ( p < 0.05) groups. There was no difference between the AC and LC results. No significant differences in PBMC H2O2 release were noted among any of the groups. OP group macrophages expressed significantly less MHC class II antigen than did AC group macrophages ( p < 0.05). No differences were noted among the LC results and either the OP or AC group's outcomes. No differences were noted in PBMC MHC class II expression among any of the groups. In all instances, the LC group's macrophage results were similar to the AC group's results. OC group macrophages produced significantly more TNF-alpha and less H2O2 than both the AC and LC groups. MHC class II protein expression was less for the OC group than for the AC group. OC group PBMCs produced more TNF-alpha. No differences in PBMC H2O2 release or MHC class II expression were noted. Laparoscopic methods better preserves the baseline values of the parameters studied.

Verification survey report of the south waste tank farm training/test tower and hazardous waste storage lockers at the West Valley demonstration project, West Valley, New York

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

Weaver, Phyllis C.

A team from ORAU's Independent Environmental Assessment and Verification Program performed verification survey activities on the South Test Tower and four Hazardous Waste Storage Lockers. Scan data collected by ORAU determined that both the alpha and alpha-plus-beta activity was representative of radiological background conditions. The count rate distribution showed no outliers that would be indicative of alpha or alpha-plus-beta count rates in excess of background. It is the opinion of ORAU that independent verification data collected support the site?s conclusions that the South Tower and Lockers sufficiently meet the site criteria for release to recycle and reuse.

p53-mediated inhibition of angiogenesis through up-regulation of a collagen prolyl hydroxylase.

PubMed

Teodoro, Jose G; Parker, Albert E; Zhu, Xiaochun; Green, Michael R

2006-08-18

Recent evidence suggests that antiangiogenic therapy is sensitive to p53 status in tumors, implicating a role for p53 in the regulation of angiogenesis. Here we show that p53 transcriptionally activates the alpha(II) collagen prolyl-4-hydroxylase [alpha(II)PH] gene, resulting in the extracellular release of antiangiogenic fragments of collagen type 4 and 18. Conditioned media from cells ectopically expressing either p53 or alpha(II)PH selectively inhibited growth of primary human endothelial cells. When expressed intracellularly or exogenously delivered, alpha(II)PH significantly inhibited tumor growth in mice. Our results reveal a genetic and biochemical linkage between the p53 tumor suppressor pathway and the synthesis of antiangiogenic collagen fragments.

Activated release of membrane-anchored TGF-alpha in the absence of cytosol

PubMed Central

1993-01-01

The ectodomain of proTGF-alpha, a membrane-anchored growth factor, is converted into soluble TGF-alpha by a regulated cellular proteolytic system that recognizes proTGF-alpha via the C-terminal valine of its cytoplasmic tail. In order to define the biochemical components involved in proTGF-alpha cleavage, we have used cells permeabilized with streptolysin O (SLO) that have been extensively washed to remove cytosol. PMA, acting through a Ca(2+)-independent protein kinase C, activates cleavage as efficiently in permeabilized cells as it does in intact cells. ProTGF-alpha cleavage is also stimulated by GTP gamma S through a mechanism whose pharmacological properties suggest the involvement of a heterotrimeric G protein acting upstream of the PMA- sensitive Ca(2+)-independent protein kinase C. Activated proTGF-alpha cleavage is dependent on ATP hydrolysis, appears not to require vesicular traffic, and acts specifically on proTGF-alpha that has reached the cell surface. These results indicate that proTGF-alpha is cleaved from the cell surface by a regulated system whose signaling, recognition, and proteolytic components are retained in cells devoid of cytosol. PMID:8314849

The Army Learning Organisation Questionnaire: Developing a Valid and Reliable Measure of Learning Organisation Characteristics

DTIC Science & Technology

2014-07-01

Telephone: 1300 333 362 Fax: (03) 9626 7999 © Commonwealth of Australia 2014 AR-016-028 July 2014 APPROVED FOR PUBLIC RELEASE... Pallant , 2007; Steiner & Norman, 2003). Validity is assessed using nomological network and its relationship to item construction using theoretical...alpha (Cronbach, 1951; De Vellis, 2003; Nunnally, 1978; Pallant , 2007; Streiner & Norman, 2003, 2008). Cronbach’s alpha builds on the utility of the

Thermionic converter

DOEpatents

Rasor, Ned S.; Britt, Edward J.

1976-01-01

A gas-filled thermionic converter is provided with a collector and an emitter having a main emitter region and an auxiliary emitter region in electrical contact with the main emitter region. The main emitter region is so positioned with respect to the collector that a main gap is formed therebetween and the auxiliary emitter region is so positioned with respect to the collector that an auxiliary gap is formed therebetween partially separated from the main gap with access allowed between the gaps to allow ionizable gas in each gap to migrate therebetween. With heat applied to the emitter the work function of the auxiliary emitter region is sufficiently greater than the work function of the collector so that an ignited discharge occurs in the auxiliary gap and the work function of the main emitter region is so related to the work function of the collector that an unignited discharge occurs in the main gap sustained by the ions generated in the auxiliary gap. A current flows through a load coupled across the emitter and collector due to the unignited discharge in the main gap.

Field emission characteristics of a small number of carbon fiber emitters

NASA Astrophysics Data System (ADS)

Tang, Wilkin W.; Shiffler, Donald A.; Harris, John R.; Jensen, Kevin L.; Golby, Ken; LaCour, Matthew; Knowles, Tim

2016-09-01

This paper reports an experiment that studies the emission characteristics of small number of field emitters. The experiment consists of nine carbon fibers in a square configuration. Experimental results show that the emission characteristics depend strongly on the separation between each emitter, providing evidence of the electric field screening effects. Our results indicate that as the separation between the emitters decreases, the emission current for a given voltage also decreases. The authors compare the experimental results to four carbon fiber emitters in a linear and square configurations as well as to two carbon fiber emitters in a paired array. Voltage-current traces show that the turn-on voltage is always larger for the nine carbon fiber emitters as compared to the two and four emitters in linear configurations, and approximately identical to the four emitters in a square configuration. The observations and analysis reported here, based on Fowler-Nordheim field emission theory, suggest the electric field screening effect depends critically on the number of emitters, the separation between them, and their overall geometric configuration.

Electrochemical formation of field emitters

DOEpatents

Bernhardt, Anthony F.

1999-01-01

Electrochemical formation of field emitters, particularly useful in the fabrication of flat panel displays. The fabrication involves field emitting points in a gated field emitter structure. Metal field emitters are formed by electroplating and the shape of the formed emitter is controlled by the potential imposed on the gate as well as on a separate counter electrode. This allows sharp emitters to be formed in a more inexpensive and manufacturable process than vacuum deposition processes used at present. The fabrication process involves etching of the gate metal and the dielectric layer down to the resistor layer, and then electroplating the etched area and forming an electroplated emitter point in the etched area.

Spectrally-engineered solar thermal photovoltaic devices

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

Lenert, Andrej; Bierman, David; Chan, Walker

A solar thermal photovoltaic device, and method of forming same, includes a solar absorber and a spectrally selective emitter formed on either side of a thermally conductive substrate. The solar absorber is configured to absorb incident solar radiation. The solar absorber and the spectrally selective emitter are configured with an optimized emitter-to-absorber area ratio. The solar thermal photovoltaic device also includes a photovoltaic cell in thermal communication with the spectrally selective emitter. The spectrally selective emitter is configured to permit high emittance for energies above a bandgap of the photovoltaic cell and configured to permit low emittance for energies belowmore » the bandgap.« less

Ultra-high Temperature Emittance Measurements for Space and Missile Applications

NASA Technical Reports Server (NTRS)

Rogers, Jan; Crandall, David

2009-01-01

Advanced modeling and design efforts for many aerospace components require high temperature emittance data. Applications requiring emittance data include propulsion systems, radiators, aeroshells, heatshields/thermal protection systems, and leading edge surfaces. The objective of this work is to provide emittance data at ultra-high temperatures. MSFC has a new instrument for the measurement of emittance at ultra-high temperatures, the Ultra-High Temperature Emissometer System (Ultra-HITEMS). AZ Technology Inc. developed the instrument, designed to provide emittance measurements over the temperature range 700-3500K. The Ultra-HITEMS instrument measures the emittance of samples, heated by lasers, in vacuum, using a blackbody source and a Fourier Transform Spectrometer. Detectors in a Nicolet 6700 FT-IR spectrometer measure emittance over the spectral range of 0.4-25 microns. Emitted energy from the specimen and output from a Mikron M390S blackbody source at the same temperature with matched collection geometry are measured. Integrating emittance over the spectral range yields the total emittance. The ratio provides a direct measure of total hemispherical emittance. Samples are heated using lasers. Optical pyrometry provides temperature data. Optical filters prevent interference from the heating lasers. Data for Inconel 718 show excellent agreement with results from literature and ASTM 835. Measurements taken from levitated spherical specimens provide total hemispherical emittance data; measurements taken from flat specimens mounted in the chamber provide near-normal emittance data. Data from selected characterization studies will be presented. The Ultra-HITEMS technique could advance space and missile technologies by advancing the knowledge base and the technology readiness level for ultra-high temperature materials.

Emittance Theory for Thin Film Selective Emitter

NASA Technical Reports Server (NTRS)

Chubb, Donald L.; Lowe, Roland A.; Good, Brian S.

1994-01-01

Thin films of high temperature garnet materials such as yttrium aluminum garnet (YAG) doped with rare earths are currently being investigated as selective emitters. This paper presents a radiative transfer analysis of the thin film emitter. From this analysis the emitter efficiency and power density are calculated. Results based on measured extinction coefficients for erbium-YAG and holmium-YAG are presented. These results indicated that emitter efficiencies of 50 percent and power densities of several watts/sq cm are attainable at moderate temperatures (less than 1750 K).

Dexamethasone but not indomethacin inhibits human phagocyte nicotinamide adenine dinucleotide phosphate oxidase activity by down-regulating expression of genes encoding oxidase components.

PubMed

Condino-Neto, A; Whitney, C; Newburger, P E

1998-11-01

We investigated the effects of dexamethasone or indomethacin on the NADPH oxidase activity, cytochrome b558 content, and expression of genes encoding the components gp91-phox and p47-phox of the NADPH oxidase system in the human monocytic THP-1 cell line, differentiated with IFN-gamma and TNF-alpha, alone or in combination, for up to 7 days. IFN-gamma and TNF-alpha, alone or in combination, caused a significant up-regulation of the NADPH oxidase system as reflected by an enhancement of the PMA-stimulated superoxide release, cytochrome b558 content, and expression of gp91-phox and p47-phox genes on both days 2 and 7 of cell culture. Noteworthy was the tremendous synergism between IFN-gamma and TNF-alpha for all studied parameters. Dexamethasone down-regulated the NADPH oxidase system of cytokine-differentiated THP-1 cells as assessed by an inhibition on the PMA-stimulated superoxide release, cytochrome b558 content, and expression of the gp91-phox and p47-phox genes. The nuclear run-on assays indicated that dexamethasone down-regulated the NADPH oxidase system at least in part by inhibiting the transcription of gp91-phox and p47-phox genes. Indomethacin inhibited only the PMA-stimulated superoxide release of THP-1 cells differentiated with IFN-gamma and TNF-alpha during 7 days. None of the other parameters was affected by indomethacin. We conclude that dexamethasone down-regulates the NADPH oxidase system at least in part by inhibiting the expression of genes encoding the gp91-phox and p47-phox components of the NADPH oxidase system.

Direct and remote modulation of L-channels in chromaffin cells: distinct actions on alpha1C and alpha1D subunits?

PubMed

Baldelli, Pietro; Hernández-Guijo, Jesus Miguel; Carabelli, Valentina; Novara, Monica; Cesetti, Tiziana; Andrés-Mateos, Eva; Montiel, Carmen; Carbone, Emilio

2004-02-01

Understanding precisely the functioning of voltage-gated Ca2+ channels and their modulation by signaling molecules will help clarifying the Ca(2+)-dependent mechanisms controlling exocytosis in chromaffin cells. In recent years, we have learned more about the various pathways through which Ca2+ channels can be up- or down-modulated by hormones and neurotransmitters and how these changes may condition chromaffin cell activity and catecolamine release. Recently, the attention has been focused on the modulation of L-channels (CaV 1), which represent the major Ca2+ current component in rat and human chromaffin cells. L-channels are effectively inhibited by the released content of secretory granules or by applying mixtures of exogenous ATP, opioids, and adrenaline through the activation of receptor-coupled G proteins. This unusual inhibition persists in a wide range of potentials and results from a direct (membrane-delimited) interaction of G protein subunits with the L-channels co-localized in membrane microareas. Inhibition of L-channels can be reversed when the cAMP/PKA pathway is activated by membrane permeable cAMP analog or when cells are exposed to isoprenaline (remote action), suggesting the existence of parallel and opposite effects on L-channel gating by distinctly activated membrane autoreceptors. Here, the authors review the molecular components underlying these two opposing signaling pathways and present new evidence supporting the presence of two L-channel types in rat chromaffin cells (alpha1C and alpha1D), which open new interesting issues concerning Ca(2+)-channel modulation. In light of recent findings on the regulation of exocytosis by Ca(2+)-channel modulation, the authors explore the possible role of L-channels in the autocontrol of catecholamine release.

Discovery of a novel nicotinic receptor antagonist for the treatment of nicotine addiction: 1-(3-Picolinium)-12-triethylammonium-dodecane dibromide (TMPD).

PubMed

Dwoskin, Linda P; Joyce, B Matthew; Zheng, Guangrong; Neugebauer, Nichole M; Manda, Vamshi K; Lockman, Paul; Papke, Roger L; Bardo, Michael T; Crooks, Peter A

2007-10-15

Limitations in efficacy and high relapse rates of currently available smoking cessation agents reveal the need for more efficacious pharmacotherapies. One strategy is to develop subtype-selective nicotinic receptor (nAChR) antagonists that inhibit nicotine-evoked dopamine (DA) release, the primary neurotransmitter involved in nicotine reward. Simple alkylation of the pyridino N-atom converts nicotine from a potent agonist into a potent antagonist. The classical antagonists, hexamethonium and decamethonium, differentiate between peripheral nAChR subtypes. Using a similar approach, we interconnected varying quaternary ammonium moieties with a lipophilic linker to provide N,N'-bis-nicotinium analogs, affording a lead compound, N,N'-dodecyl-1,12-diyl-bis-3-picolinium dibromide (bPiDDB), which inhibited nicotine-evoked DA release and decreased nicotine self-administration. The current work describes a novel compound, 1-(3-picolinium)-12-triethylammonium-dodecane dibromide (TMPD), a hybrid of bPiDDB and decamethonium. TMPD completely inhibited (IC(50)=500 nM) nicotine-evoked DA release from superfused rat striatal slices, suggesting that TMPD acts as a nAChR antagonist at more than one subtype. TMPD (1 microM) inhibited the response to acetylcholine at alpha3beta4, alpha4beta4, alpha4beta2, and alpha1beta1varepsilondelta receptors expressed in Xenopus oocytes. TMPD had a 2-fold higher affinity than choline for the blood-brain barrier choline transporter, suggesting brain bioavailability. TMPD did not inhibit hyperactivity in nicotine sensitized rats, but significantly and specifically decreased nicotine self-administration. Together, the results suggest that TMPD may have the ability to reduce the rewarding effect of nicotine with minimal side effects, a pharmacological profile indicative of potential clinical utility for the treatment of tobacco dependence.

Evaluation of selected thermal control coatings for long-life space structures

NASA Technical Reports Server (NTRS)

Teichman, Louis A.; Slemp, Wayne S.; Witte, William G., Jr.

1992-01-01

Graphite-reinforced resin matrix composites are being considered for spacecraft structural applications because of their light weight, high stiffness, and lower thermal expansion. Thin protective coatings with stable optical properties and the proper ratio of solar absorption (alpha sub s) to thermal emittance (epsilon) minimize orbital thermal extremes and protect these materials against space environment degradation. Sputtered coatings applied directly to graphite/epoxy composite surfaces and anodized coatings applied to thin aluminum foil were studied for use both as an atomic oxygen barrier and as thermal control coatings. Additional effort was made to develop nickel-based coatings which could be applied directly to composites. These coating systems were selected because their inherent tenacity made them potentially more reliable than commercial white paints for long-life space missions. Results indicate that anodized aluminum foil coatings are suitable for tubular and flat composite structures on large platforms in low Earth orbit. Anodized foil provides protection against some elements of the natural space environment (atomic oxygen, ultraviolet, and particulate radiation) and offers a broad range of tailored alpha sub s/epsilon. The foil is readily available and can be produced in large quantities, while the anodizing process is a routine commercial technique.

Rapid method to determine 226Ra in steel samples

DOE PAGES

Maxwell, Sherrod L.; Culligan, Brian; Hutchison, Jay B.; ...

2017-09-22

The rapid measurement of 226Ra in steel samples is very important in the event of a radiological emergency. 226Ra (T 1/2 = 1600 y) is a natural radionuclide present in the environment and a highly toxic alpha-emitter. Due to its long life and tendency to concentrate in bones, 226Ra ingestion or inhalation can lead to significant committed dose to individuals. A new method for the determination of 226Ra in steel samples has been developed at the Savannah River Environmental Laboratory. The new method employs a rugged acid digestion method that includes hydrofluoric acid, followed by a single precipitation step tomore » rapidly preconcentrate the radium and remove most of the dissolved steel sample matrix. Radium is then separated using a combination of cation exchange and extraction chromatography, and 226Ra is measured by alpha spectrometry. This approach has a sample preparation time of ~ 8 h for steel samples, has a very high tracer yield (> 88%), and removes interferences effectively. A 133Ba yield tracer is used so that samples can be counted immediately following the separation method, avoiding lengthy ingrowth times that are required in other methods.« less

Approaches to Manufacturing Alpha Emitters For Radioimmunotherapeutic Drugs

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

Gaylord King, A.; Givens, Kenneth R.; Miller, William H.

Several alpha emitting isotopes have been proposed for radioimmunotherapy. To produce these nuclides reliably and in quantities needed, unique manufacturing approaches will be required. This paper describes the approaches that are being developed for the manufacture of 225Actinium (225 Ac) that decays to 213Bismuth (213 Bi) and the commercial manufacturing approaches. Oak Ridge National Laboratory (ORNL) currently supplies the actinium used for research and medical use. Today the ORNL 233U stockpiles only provide sufficient material for research quantities of 213 Bi. At the Institute for Transuranium Elements (ITU), in Karlsruhe, researchers have also developed a method of irradiating radium-226 withmore » protons in a cyclotron to produce actinium- 225 through the reaction 226Ra (p, 2n) 225Ac. Researchers from the Missouri University (MU), the Missouri University Research Reactor (MURR), MedActinium, Inc. and Los Alamos National Laboratory (LANL) are working on a collaborative effort to benchmark and optimize the production of 213Bi via neutron bombardment of 226Ra. MedActinium, Inc., in collaboration with commercial and institutional investigators at PG Research Foundation (PGRF) and Memorial Sloan Kettering Cancer Center (MSKCC), is developing commercial approaches to manufacturing these unique radioimmunotherapeutic drugs.« less

Rapid method to determine 226Ra in steel samples

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

Maxwell, Sherrod L.; Culligan, Brian; Hutchison, Jay B.

The rapid measurement of 226Ra in steel samples is very important in the event of a radiological emergency. 226Ra (T 1/2 = 1600 y) is a natural radionuclide present in the environment and a highly toxic alpha-emitter. Due to its long life and tendency to concentrate in bones, 226Ra ingestion or inhalation can lead to significant committed dose to individuals. A new method for the determination of 226Ra in steel samples has been developed at the Savannah River Environmental Laboratory. The new method employs a rugged acid digestion method that includes hydrofluoric acid, followed by a single precipitation step tomore » rapidly preconcentrate the radium and remove most of the dissolved steel sample matrix. Radium is then separated using a combination of cation exchange and extraction chromatography, and 226Ra is measured by alpha spectrometry. This approach has a sample preparation time of ~ 8 h for steel samples, has a very high tracer yield (> 88%), and removes interferences effectively. A 133Ba yield tracer is used so that samples can be counted immediately following the separation method, avoiding lengthy ingrowth times that are required in other methods.« less

Effect of radiation-induced amorphization on smectite dissolution.

PubMed

Fourdrin, C; Allard, T; Monnet, I; Menguy, N; Benedetti, M; Calas, G

2010-04-01

Effects of radiation-induced amorphization of smectite were investigated using artificial irradiation. Beams of 925 MeV Xenon ions with radiation dose reaching 73 MGy were used to simulate the effects generated by alpha recoil nuclei or fission products in the context of high level nuclear waste repository. Amorphization was controlled by X-ray diffraction, transmission electron microscopy, and Fourier transform infrared spectroscopy. An important coalescence of the smectite sheets was observed which lead to a loss of interparticle porosity. The amorphization is revealed by a loss of long-range structure and accompanied by dehydroxylation. The dissolution rate far-from-equilibrium shows that the amount of silica in solution is two times larger in the amorphous sample than in the reference clay, a value which may be enhanced by orders of magnitude when considering the relative surface area of the samples. Irradiation-induced amorphization thus facilitates dissolution of the clay-derived material. This has to be taken into account for the safety assessment of high level nuclear waste repository, particularly in a scenario of leakage of the waste package which would deliver alpha emitters able to amorphize smectite after a limited period of time.

Comparison of U.S. Environmental Protection Agency's CAP88 PC Versions 3.0 and 4.0.

PubMed

Jannik, Tim; Farfan, Eduardo B; Dixon, Ken; Newton, Joseph; Sailors, Christopher; Johnson, Levi; Moore, Kelsey; Stahman, Richard

2015-08-01

The Savannah River National Laboratory (SRNL) with the assistance of Georgia Regents University, completed a comparison of the U.S. Environmental Protection Agency's (U.S. EPA) environmental dosimetry code CAP88 PC V3.0 with the recently developed V4.0. CAP88 is a set of computer programs and databases used for estimation of dose and risk from radionuclide emissions to air. At the U.S. Department of Energy's Savannah River Site, CAP88 is used by SRNL for determining compliance with U.S. EPA's National Emission Standards for Hazardous Air Pollutants (40 CFR 61, Subpart H) regulations. Using standardized input parameters, individual runs were conducted for each radionuclide within its corresponding database. Some radioactive decay constants, human usage parameters, and dose coefficients changed between the two versions, directly causing a proportional change in the total effective dose. A detailed summary for select radionuclides of concern at the Savannah River Site (60Co, 137Cs, 3H, 129I, 239Pu, and 90Sr) is provided. In general, the total effective doses will decrease for alpha/beta emitters because of reduced inhalation and ingestion rates in V4.0. However, for gamma emitters, such as 60Co and 137Cs, the total effective doses will increase because of changes U.S. EPA made in the external ground shine calculations.

Recovering the systemic redshift of galaxies from their Lyman-alpha line profile

NASA Astrophysics Data System (ADS)

Verhamme, A.; Garel, T.; Ventou, E.; Contini, T.; Bouché, N.; Herenz, E. C.; Richard, J.; Bacon, R.; Schmidt, K. B.; Maseda, M.; Marino, R. A.; Brinchmann, J.; Cantalupo, S.; Caruana, J.; Clément, B.; Diener, C.; Drake, A. B.; Hashimoto, T.; Inami, H.; Kerutt, J.; Kollatschny, W.; Leclercq, F.; Patrício, V.; Schaye, J.; Wisotzki, L.; Zabl, J.

2018-04-01

The Lyman alpha (Lyα) line of Hydrogen is a prominent feature in the spectra of star-forming galaxies, usually redshifted by a few hundreds of km s-1 compared to the systemic redshift. This large offset hampers follow-up surveys, galaxy pair statistics and correlations with quasar absorption lines when only Lyα is available. We propose diagnostics that can be used to recover the systemic redshift directly from the properties of the Lyα line profile. We use spectroscopic observations of Lyman-Alpha Emitters (LAEs) for which a precise measurement of the systemic redshift is available. Our sample contains 13 sources detected between z ≈ 3 and z ≈ 6 as part of various Multi Unit Spectroscopic Explorer (MUSE) Guaranteed Time Observations (GTO). We also include a compilation of spectroscopic Lyα data from the literature spanning a wide redshift range (z ≈ 0 - 8). First, restricting our analysis to double-peaked Lyα spectra, we find a tight correlation between the velocity offset of the red peak with respect to the systemic redshift, V_peak^red, and the separation of the peaks. Secondly, we find a correlation between V_peak^red and the full width at half maximum of the Lyα line. Fitting formulas, to estimate systemic redshifts of galaxies with an accuracy of ≤100 km s-1 when only the Lyα emission line is available, are given for the two methods.

Involvement of the Clock Gene Rev-erb alpha in the Regulation of Glucagon Secretion in Pancreatic Alpha-Cells

PubMed Central

Vieira, Elaine; Marroquí, Laura; Figueroa, Ana Lucia C.; Merino, Beatriz; Fernandez-Ruiz, Rebeca; Nadal, Angel; Burris, Thomas P.; Gomis, Ramon; Quesada, Ivan

2013-01-01

Disruption of pancreatic clock genes impairs pancreatic beta-cell function, leading to the onset of diabetes. Despite the importance of pancreatic alpha-cells in the regulation of glucose homeostasis and in diabetes pathophysiology, nothing is known about the role of clock genes in these cells. Here, we identify the clock gene Rev-erb alpha as a new intracellular regulator of glucagon secretion. Rev-erb alpha down-regulation by siRNA (60–70% inhibition) in alphaTC1-9 cells inhibited low-glucose induced glucagon secretion (p<0.05) and led to a decrease in key genes of the exocytotic machinery. The Rev-erb alpha agonist GSK4112 increased glucagon secretion (1.6 fold) and intracellular calcium signals in alphaTC1-9 cells and mouse primary alpha-cells, whereas the Rev-erb alpha antagonist SR8278 produced the opposite effect. At 0.5 mM glucose, alphaTC1-9 cells exhibited intrinsic circadian Rev-erb alpha expression oscillations that were inhibited by 11 mM glucose. In mouse primary alpha-cells, glucose induced similar effects (p<0.001). High glucose inhibited key genes controlled by AMPK such as Nampt, Sirt1 and PGC-1 alpha in alphaTC1-9 cells (p<0.05). AMPK activation by metformin completely reversed the inhibitory effect of glucose on Nampt-Sirt1-PGC-1 alpha and Rev-erb alpha. Nampt inhibition decreased Sirt1, PGC-1 alpha and Rev-erb alpha mRNA expression (p<0.01) and glucagon release (p<0.05). These findings identify Rev-erb alpha as a new intracellular regulator of glucagon secretion via AMPK/Nampt/Sirt1 pathway. PMID:23936124

Evidence of low injection efficiency for implanted p-emitters in bipolar 4H-SiC high-voltage diodes

NASA Astrophysics Data System (ADS)

Matthus, Christian D.; Huerner, Andreas; Erlbacher, Tobias; Bauer, Anton J.; Frey, Lothar

2018-06-01

In this study, the influence of the emitter efficiency on the forward current-voltage characteristics, especially the conductivity modulation of bipolar SiC-diodes was analyzed. It was determined that the emitter efficiency of p-emitters formed by ion implantation is significantly lower compared to p-emitters formed by epitaxy. In contrast to comparable studies, experimental approach was arranged that the influence of the quality of the drift-layer or the thickness of the emitter on the conductivity modulation could be excluded for the fabricated bipolar SiC-diodes of this work. Thus, it can be established that the lower emitter injection efficiency is mainly caused by the reduced electron lifetime in p-emitters formed by ion implantation. Therefore, a significant enhancement of the electron lifetime in implanted p-emitters is mandatory for e.g. SiC-MPS-diodes where the functionality of the devices depends significantly on the injection efficiency.

Measurement of transverse emittance and coherence of double-gate field emitter array cathodes

PubMed Central

Tsujino, Soichiro; Das Kanungo, Prat; Monshipouri, Mahta; Lee, Chiwon; Miller, R.J. Dwayne

2016-01-01

Achieving small transverse beam emittance is important for high brightness cathodes for free electron lasers and electron diffraction and imaging experiments. Double-gate field emitter arrays with on-chip focussing electrode, operating with electrical switching or near infrared laser excitation, have been studied as cathodes that are competitive with photocathodes excited by ultraviolet lasers, but the experimental demonstration of the low emittance has been elusive. Here we demonstrate this for a field emitter array with an optimized double-gate structure by directly measuring the beam characteristics. Further we show the successful application of the double-gate field emitter array to observe the low-energy electron beam diffraction from suspended graphene in minimal setup. The observed low emittance and long coherence length are in good agreement with theory. These results demonstrate that our all-metal double-gate field emitters are highly promising for applications that demand extremely low-electron bunch-phase space volume and large transverse coherence. PMID:28008918

Measurement of transverse emittance and coherence of double-gate field emitter array cathodes

NASA Astrophysics Data System (ADS)

Tsujino, Soichiro; Das Kanungo, Prat; Monshipouri, Mahta; Lee, Chiwon; Miller, R. J. Dwayne

2016-12-01

Achieving small transverse beam emittance is important for high brightness cathodes for free electron lasers and electron diffraction and imaging experiments. Double-gate field emitter arrays with on-chip focussing electrode, operating with electrical switching or near infrared laser excitation, have been studied as cathodes that are competitive with photocathodes excited by ultraviolet lasers, but the experimental demonstration of the low emittance has been elusive. Here we demonstrate this for a field emitter array with an optimized double-gate structure by directly measuring the beam characteristics. Further we show the successful application of the double-gate field emitter array to observe the low-energy electron beam diffraction from suspended graphene in minimal setup. The observed low emittance and long coherence length are in good agreement with theory. These results demonstrate that our all-metal double-gate field emitters are highly promising for applications that demand extremely low-electron bunch-phase space volume and large transverse coherence.

Ageing enhances alpha-synuclein, ubiquitin and endoplasmic reticular stress protein expression in the nigral neurons of Asian Indians.

PubMed

Alladi, Phalguni Anand; Mahadevan, Anita; Vijayalakshmi, K; Muthane, Uday; Shankar, S K; Raju, T R

2010-11-01

Accumulating evidences suggest that dopaminergic neuronal loss in the substantia nigra pars compacta (SNpc) during ageing and in Parkinson's disease (PD) is linked to neurodegenerative changes like exponential increase in alpha-synuclein expression and protein misfolding. Lewy body formation is also a quintessential observation in neurodegeneration and PD. In experimental models of PD, GRP78 a neuroprotective endoplasmic reticulum (ER) chaperone protein targets misfolded proteins for degradation and prevents release of caspase12 from the ER. Release of active caspase12 and its translocation to the nucleus induces ER mediated apoptosis. The effect of ageing on these proteins in human nigra is not known. We evaluated alpha-synuclein, caspase12, GRP78 and ubiquitin expression in the SNpc of Asian Indians, using immunohistochemistry and stereology. The number of alpha-synuclein and caspase12 immunoreactive neurons increased gradually with age whereas the number of GRP78-labeled neurons remained stable. In contrast, GRP78 protein expression was significantly upregulated with age, while alpha-synuclein and caspase12 increased slightly. An increase in the size and numbers of marinesco bodies was prominent after the sixth decade. The mild increase in alpha-synuclein expression and occurrence of marinesco bodies suggests ageing induced protein misfolding and GRP78 upregulation indicates presence of ER stress. The logarithmic upregulation of GRP78 could even be an indicator of neuroprotective or neuromodulatory response of ER to protein misfolding and initiation of unfolded protein response pathway. Since dopaminergic neurons are preserved in ageing Asian Indians, our study possibly signifies better proteasomal or ER response and partially explains the lower prevalence of PD in them. Copyright 2010 Elsevier Ltd. All rights reserved.

Coordinate regulation of estrogen-mediated fibronectin matrix assembly and epidermal growth factor receptor transactivation by the G protein-coupled receptor, GPR30.

PubMed

Quinn, Jeffrey A; Graeber, C Thomas; Frackelton, A Raymond; Kim, Minsoo; Schwarzbauer, Jean E; Filardo, Edward J

2009-07-01

Estrogen promotes changes in cytoskeletal architecture not easily attributed to the biological action of estrogen receptors, ERalpha and ERbeta. The Gs protein-coupled transmembrane receptor, GPR30, is linked to specific estrogen binding and rapid estrogen-mediated release of heparin-bound epidermal growth factor. Using marker rescue and dominant interfering mutant strategies, we show that estrogen action via GPR30 promotes fibronectin (FN) matrix assembly by human breast cancer cells. Stimulation with 17beta-estradiol or the ER antagonist, ICI 182, 780, results in the recruitment of FN-engaged integrin alpha5beta1 conformers to fibrillar adhesions and the synthesis of FN fibrils. Concurrent with this cellular response, GPR30 promotes the formation of Src-dependent, Shc-integrin alpha5beta1 complexes. Function-blocking antibodies directed against integrin alpha5beta1 or soluble Arg-Gly-Asp peptide fragments derived from FN specifically inhibited GPR30-mediated epidermal growth factor receptor transactivation. Estrogen-mediated FN matrix assembly and epidermal growth factor receptor transactivation were similarly disrupted in integrin beta1-deficient GE11 cells, whereas reintroduction of integrin beta1 into GE11 cells restored these responses. Mutant Shc (317Y/F) blocked GPR30-induced FN matrix assembly and tyrosyl phosphorylation of erbB1. Interestingly, relative to recombinant wild-type Shc, 317Y/F Shc was more readily retained in GPR30-induced integrin alpha5beta1 complexes, yet this mutant did not prevent endogenous Shc-integrin alpha5beta1 complex formation. Our results suggest that GPR30 coordinates estrogen-mediated FN matrix assembly and growth factor release in human breast cancer cells via a Shc-dependent signaling mechanism that activates integrin alpha5beta1.

Searching for Lyman-alpha Emitters as a Probe of Cosmic Reionization and Peering Inside Galaxies in the First Two Billion Years

NASA Astrophysics Data System (ADS)

Jung, Intae; Finkelstein, Steven; CANDELS team

2018-01-01

In the reionization era an immediately accessible method for studying the intergalactic medium is to measure the equivalent width distribution of Lyman-alpha emission from galaxies with follow-up spectroscopy. To search for Lyman-alpha emission from galaxies at z ~ 5-8, we perform spectroscopic observations of candidate galaxies from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS). We utilize data from the Keck DEIMOS (optical) and MOSFIRE (near-infrared) spectrographs, ensuring a comprehensive wavelength coverage of Lyman-alpha emission at z ~ 5-8. We have a total of 1170 object-hours of spectroscopic integration of galaxies at z > 5: 118 galaxies with DEIMOS and 69 galaxies with MOSFIRE. The equivalent width distribution of Lyman-alpha emission is constrained with the number of detected objects from our dataset by constructing detailed simulations of mock emission lines, which consider observational conditions and the photometric redshift probability distribution function. We present our robust measure of the evolution of the Lyman-alpha emission equivalent width distribution at z ~ 5-8.Understanding what drives star-formation quenching in the early universe is a long-standing puzzle. To reveal the hidden relation of quenching with galaxy structural properties, particularly central stellar mass density, we perform the first spatially resolved stellar population study of galaxies at z ~ 4, utilizing the CANDELS imaging data set over the GOODS-S field. We examine 166 photometric-redshift-selected galaxies at 3.5 < z < 4.0 with additional deep K-band survey data from the HAWK-I UDS and GOODS Survey which covers the 4000Å break at these redshifts. We estimate the stellar mass, star formation rate, and dust extinction for galaxy inner and outer regions via spatially resolved spectral energy distribution fitting based on a Markov Chain Monte Carlo algorithm. By comparing specific star formation rates (sSFRs) between inner and outer parts of the galaxies we find that the majority of galaxies with high central mass densities show evidence for a preferentially lower sSFR in their centers than in their outer regions, indicative of reduced sSFRs in their central regions.

A model for optimizing delivery of targeted radionuclide therapies into resection cavity margins for the treatment of primary brain cancers.

PubMed

Raghavan, Raghu; Howell, Roger W; Zalutsky, Michael R

2017-06-01

Radionuclides conjugated to molecules that bind specifically to cancer cells are of great interest as a means to increase the specificity of radiotherapy. Currently, the methods to disseminate these targeted radiotherapeutics have been either systemic delivery or by bolus injection into the tumor or tumor resection cavity. Herein we model a potentially more efficient method of delivery, namely pressure-driven fluid flow, called convection-enhanced delivery (CED), where a device infuses the molecules in solution (or suspension) directly into the tissue of interest. In particular, we focus on the setting of primary brain cancer after debulking surgery, where the tissue margins surrounding the surgical resection cavity are infiltrated with tumor cells and the most frequent sites of tumor recurrence. We develop the combination of fluid flow, chemical kinetics, and radiation dose models needed to examine such protocols. We focus on Auger electron-emitting radionuclides (e.g. 67 Ga, 77 Br, 111 In, 125 I, 123 I, 193m Pt, 195m Pt) whose short range makes them ideal for targeted therapy in this setting of small foci of tumor spread within normal tissue. By solving these model equations, we confirm that a CED protocol is promising in allowing sufficient absorbed dose to destroy cancer cells with minimal absorbed dose to normal cells at clinically feasible activity levels. We also show that Auger emitters are ideal for this purpose while the longer range alpha particle emitters fail to meet criteria for effective therapy (as neither would energetic beta particle emitters). The model is used with simplified assumptions on the geometry and homogeneity of brain tissue to allow semi-analytic solutions to be displayed, and with the purpose of a first examination of this new delivery protocol proposed for radionuclide therapy. However, we emphasize that it is immediately extensible to personalized therapy treatment planning as we have previously shown for conventional CED, at the price of requiring a fully numerical computerized approach.

Utilization of peptide carrier system to improve intestinal absorption: targeting prolidase as a prodrug-converting enzyme

NASA Technical Reports Server (NTRS)

Bai, J. P.; Hu, M.; Subramanian, P.; Mosberg, H. I.; Amidon, G. L.

1992-01-01

The feasibility of targeting prolidase as a peptide prodrug-converting enzyme has been examined. The enzymatic hydrolysis by prolidase of substrates for the peptide transporter L-alpha-methyldopa-pro and several dipeptide analogues without an N-terminal alpha-amino group (phenylpropionylproline, phenylacetylproline, N-benzoylproline, and N-acetylproline) was investigated. The Michaelis-Menten parameters Km and Vmax for L-alpha-methyldopa-pro are 0.09 +/- 0.02 mM and 3.98 +/- 0.25 mumol/min/mg protein, respectively. However, no hydrolysis of the dipeptide analogues without an N-terminal alpha-amino group is observed, suggesting that an N-terminal alpha-amino group is required for prolidase activity. These results demonstrate that prolidase may serve as a prodrug-converting enzyme for the dipeptide-type prodrugs, utilizing the peptide carrier for transport of prodrugs into the mucosal cells and prolidase, a cytosolic enzyme, to release the drug. However, a free alpha-amino group appears to be necessary for prolidase hydrolysis.

Anaplerotic input is sufficient to induce time-dependent potentiation of insulin release in rat pancreatic islets.

PubMed

Gunawardana, Subhadra C; Liu, Yi-Jia; Macdonald, Michael J; Straub, Susanne G; Sharp, Geoffrey W G

2004-11-01

Nutrients that induce biphasic insulin release, such as glucose and leucine, provide acetyl-CoA and anaplerotic input in the beta-cell. The first phase of release requires increased ATP production leading to increased intracellular Ca(2+) concentration ([Ca(2+)](i)). The second phase requires increased [Ca(2+)](i) and anaplerosis. There is strong evidence to indicate that the second phase is due to augmentation of Ca(2+)-stimulated release via the K(ATP) channel-independent pathway. To test whether the phenomenon of time-dependent potentiation (TDP) has similar properties to the ATP-sensitive K(+) channel-independent pathway, we monitored the ability of different agents that provide acetyl-CoA and anaplerotic input or both of these inputs to induce TDP. The results show that anaplerotic input is sufficient to induce TDP. Interestingly, among the agents tested, the nonsecretagogue glutamine, the nonhydrolyzable analog of leucine aminobicyclo[2.2.1]heptane-2-carboxylic acid, and succinic acid methyl ester all induced TDP, and all significantly increased alpha-ketoglutarate levels in the islets. In conclusion, anaplerosis that enhances the supply and utilization of alpha-ketoglutarate in the tricarboxylic acid cycle appears to play an essential role in the generation of TDP.

Phosphorylation of TNF-alpha converting enzyme by gastrin-releasing peptide induces amphiregulin release and EGF receptor activation.

PubMed

Zhang, Qing; Thomas, Sufi M; Lui, Vivian Wai Yan; Xi, Sichuan; Siegfried, Jill M; Fan, Huizhou; Smithgall, Thomas E; Mills, Gordon B; Grandis, Jennifer Rubin

2006-05-02

G protein-coupled receptors induce EGF receptor (EGFR) signaling, leading to the proliferation and invasion of cancer cells. Elucidation of the mechanism of EGFR activation by G protein-coupled receptors may identify new signaling paradigms. A gastrin-releasing peptide (GRP)/GRP receptor-mediated autocrine pathway was previously described in squamous cell carcinoma of head and neck. In the present study, we demonstrate that TNF-alpha converting enzyme (TACE), a disintegrin and metalloproteinse-17, undergoes a Src-dependent phosphorylation that regulates release of the EGFR ligand amphiregulin upon GRP treatment. Further investigation reveals the phosphatidylinositol 3-kinase (PI3-K) as the intermediate of c-Src and TACE, contributing to their association and TACE phosphorylation. Phosphoinositide-dependent kinase 1 (PDK1), a downstream target of PI3-K, has been identified as the previously undescribed kinase to directly phosphorylate TACE upon GRP treatment. These findings suggest a signaling cascade of GRP-Src-PI3-K-PDK1-TACE-amphiregulin-EGFR with multiple points of interaction, translocation, and phosphorylation. Furthermore, knockdown of PDK1 augmented the antitumor effects of the EGFR inhibitor erlotinib, indicating PDK1 as a therapeutic target to improve the clinical response to EGFR inhibitors.

Acidic attack of perfluorinated alkyl ether lubricant molecules by metal oxide surfaces

NASA Technical Reports Server (NTRS)

Zehe, Michael J.; Faut, Owen D.

1989-01-01

The reactions of linear perfluoropolyalkylether (PFAE) lubricants with alpha-Fe2O3 and Fe2O3-based solid superacids were studied. The reaction with alpha-Fe2O3 proceeds in two stages. The first stage is an initial slow catalytic decomposition of the fluid. This reaction releases reactive gaseous products which attach the metal oxide and convert it to FeF3. The second stage is a more rapid decomposition of the fluid, effected by the surface FeF3. A study of the inital breakdown step was performed using alpha-Fe2O3, alpha-Fe2O3 preconverted to FeF3, and sulfate-promoted alpha-Fe2O3 superacids. The results indicate that the breakdown reaction involves acidic attack at fluorine atoms on acetal carbons in the linear PFAE. Possible approaches to combat the problem are outlined.

Electrochemical formation of field emitters

DOEpatents

Bernhardt, A.F.

1999-03-16

Electrochemical formation of field emitters, particularly useful in the fabrication of flat panel displays is disclosed. The fabrication involves field emitting points in a gated field emitter structure. Metal field emitters are formed by electroplating and the shape of the formed emitter is controlled by the potential imposed on the gate as well as on a separate counter electrode. This allows sharp emitters to be formed in a more inexpensive and manufacturable process than vacuum deposition processes used at present. The fabrication process involves etching of the gate metal and the dielectric layer down to the resistor layer, and then electroplating the etched area and forming an electroplated emitter point in the etched area. 12 figs.

Emittance measurements of Space Shuttle orbiter reinforced carbon-carbon

NASA Technical Reports Server (NTRS)

Caram, Jose M.; Bouslog, Stanley A.; Cunnington, George R., Jr.

1992-01-01

The spectral and total normal emittance of the Reinforced Carbon-Carbon (RCC) used on Space Shuttle nose cap and wing leading edges has been measured at room temperature and at surface temperatures of 1200 to 2100 K. These measurements were made on virgin and two flown RCC samples. Room temperature directional emittance data were also obtained and were used to determine the total hemispherical emittance of RCC as a function of temperature. Results of the total normal emittance for the virgin samples showed good agreement with the current RCC emittance design curve; however, the data from the flown samples showed an increase in the emittance at high temperature possibly due to exposure from flight environments.

Radial arrays of nano-electrospray ionization emitters and methods of forming electrosprays

DOEpatents

Kelly, Ryan T [West Richland, WA; Tang, Keqi [Richland, WA; Smith, Richard D [Richland, WA

2010-10-19

Electrospray ionization emitter arrays, as well as methods for forming electrosprays, are described. The arrays are characterized by a radial configuration of three or more nano-electrospray ionization emitters without an extractor electrode. The methods are characterized by distributing fluid flow of the liquid sample among three or more nano-electrospray ionization emitters, forming an electrospray at outlets of the emitters without utilizing an extractor electrode, and directing the electrosprays into an entrance to a mass spectrometry device. Each of the nano-electrospray ionization emitters can have a discrete channel for fluid flow. The nano-electrospray ionization emitters are circularly arranged such that each is shielded substantially equally from an electrospray-inducing electric field.

Localization of alpha 1-adrenoceptors in rat and human hearts by immunocytochemistry.

PubMed

Schulze, W; Fu, M L

1996-01-01

The localization of the alpha 1 adrenoceptors (alpha 1-AR) in the heart tissues from rat and human and in the cultured heart cells from neonatal rats was studied by indirect immunofluorescence and postembedding electronmicroscopical immuno-gold technique. With antipeptide antibodies directed against the second extracellular loop of the human alpha 1-AR (AS sequence 192-218), this receptor was found to be localized along the sarcolemma in both human and rat hearts. Similar localization sites were detected in cultivated rat neonatal cardiomyocytes. Beside the localization in cardiomyocytes, alpha 1-AR were identified in endothelial cells of capillaries and smooth muscle cells of coronary vessels, in neuronal endings, in mast cells of cultivated heart cells but not, or in less amount in fibroblasts. Interestingly, in the right atrium of rat heart the localization of alpha 1-AR was found to be near or on atrial natriuretic factor (ANF) granules, providing the basis for the alpha-adrenergic influence on ANF release. The immunocytochemical studies further confirm and complete the findings known by using autoradiographic binding studies with specific ligands.

Construction and measurements of a vacuum-swing-adsorption radon-mitigation system

NASA Astrophysics Data System (ADS)

Schnee, R. W.; Bunker, R.; Ghulam, G.; Jardin, D.; Kos, M.; Tenney, A. S.

2013-08-01

Long-lived alpha and beta emitters in the 222Rn decay chain on (and near) detector surfaces may be the limiting background in many experiments attempting to detect dark matter or neutrinoless double beta decay, and in screening detectors. In order to reduce backgrounds from radon-daughter plate-out onto the wires of the Beta Cage during its assembly, an ultra-low-radon cleanroom is being commissioned at Syracuse University using a vacuum-swing-adsorption radon-mitigation system. The radon filter shows ˜20× reduction at its output, from 7.47±0.56 to 0.37±0.12 Bq/m3, and the cleanroom radon activity meets project requirements, with a lowest achieved value consistent with that of the filter, and levels consistently < 2 Bq/m3.

The Oxidation Rate of SiC in High Pressure Water Vapor Environments

NASA Technical Reports Server (NTRS)

Opila, Elizabeth J.; Robinson, R. Craig

1999-01-01

CVD SiC and sintered alpha-SiC samples were exposed at 1316 C in a high pressure burner rig at total pressures of 5.7, 15, and 25 atm for times up to 100h. Variations in sample emittance for the first nine hours of exposure were used to determine the thickness of the silica scale as a function of time. After accounting for volatility of silica in water vapor, the parabolic rate constants for Sic in water vapor pressures of 0.7, 1.8 and 3.1 atm were determined. The dependence of the parabolic rate constant on the water vapor pressure yielded a power law exponent of one. Silica growth on Sic is therefore limited by transport of molecular water vapor through the silica scale.

Redefining relative biological effectiveness in the context of the EQDX formalism: implications for alpha-particle emitter therapy.

PubMed

Hobbs, Robert F; Howell, Roger W; Song, Hong; Baechler, Sébastien; Sgouros, George

2014-01-01

Alpha-particle radiopharmaceutical therapy (αRPT) is currently enjoying increasing attention as a viable alternative to chemotherapy for targeting of disseminated micrometastatic disease. In theory, αRPT can be personalized through pre-therapeutic imaging and dosimetry. However, in practice, given the particularities of α-particle emissions, a dosimetric methodology that accurately predicts the thresholds for organ toxicity has not been reported. This is in part due to the fact that the biological effects caused by α-particle radiation differ markedly from the effects caused by traditional external beam (photon or electron) radiation or β-particle emitting radiopharmaceuticals. The concept of relative biological effectiveness (RBE) is used to quantify the ratio of absorbed doses required to achieve a given biological response with alpha particles versus a reference radiation (typically a beta emitter or external beam radiation). However, as conventionally defined, the RBE varies as a function of absorbed dose and therefore a single RBE value is limited in its utility because it cannot be used to predict response over a wide range of absorbed doses. Therefore, efforts are underway to standardize bioeffect modeling for different fractionation schemes and dose rates for both nuclear medicine and external beam radiotherapy. Given the preponderant use of external beams of radiation compared to nuclear medicine in cancer therapy, the more clinically relevant quantity, the 2 Gy equieffective dose, EQD2(α/β), has recently been proposed by the ICRU. In concert with EQD2(α/β), we introduce a new, redefined RBE quantity, named RBE2(α/β), as the ratio of the two linear coefficients that characterize the α particle absorbed dose-response curve and the low-LET megavoltage photon 2 Gy fraction equieffective dose-response curve. The theoretical framework for the proposed new formalism is presented along with its application to experimental data obtained from irradiation of a breast cancer cell line. Radiobiological parameters are obtained using the linear quadratic model to fit cell survival data for MDA-MB-231 human breast cancer cells that were irradiated with either α particles or a single fraction of low-LET (137)Cs γ rays. From these, the linear coefficient for both the biologically effective dose (BED) and the EQD2(α/β) response lines were derived for fractionated irradiation. The standard RBE calculation, using the traditional single fraction reference radiation, gave RBE values that ranged from 2.4 for a surviving fraction of 0.82-6.0 for a surviving fraction of 0.02, while the dose-independent RBE2(4.6) value was 4.5 for all surviving fraction values. Furthermore, bioeffect modeling with RBE2(α/β) and EQD2(α/β) demonstrated the capacity to predict the surviving fraction of cells irradiated with acute and fractionated low-LET radiation, α particles and chronic exponentially decreasing dose rates of low-LET radiation. RBE2(α/β) is independent of absorbed dose for α-particle emitters and it provides a more logical framework for data reporting and conversion to equieffective dose than the conventional dose-dependent definition of RBE. Moreover, it provides a much needed foundation for the ongoing development of an α-particle dosimetry paradigm and will facilitate the use of tolerance dose data available from external beam radiation therapy, thereby helping to develop αRPT as a single modality as well as for combination therapies.

Redefining Relative Biological Effectiveness in the Context of the EQDX Formalism: Implications for Alpha-Particle Emitter Therapy.

PubMed

Hobbs, Robert F; Howell, Roger W; Song, Hong; Baechler, Sébastien; Sgouros, George

2013-12-30

Alpha-particle radiopharmaceutical therapy (αRPT) is currently enjoying increasing attention as a viable alternative to chemotherapy for targeting of disseminated micrometastatic disease. In theory, αRPT can be personalized through pre-therapeutic imaging and dosimetry. However, in practice, given the particularities of α-particle emissions, a dosimetric methodology that accurately predicts the thresholds for organ toxicity has not been reported. This is in part due to the fact that the biological effects caused by α-particle radiation differ markedly from the effects caused by traditional external beam (photon or electron) radiation or β-particle emitting radiopharmaceuticals. The concept of relative biological effectiveness (RBE) is used to quantify the ratio of absorbed doses required to achieve a given biological response with alpha particles versus a reference radiation (typically a beta emitter or external beam radiation). However, as conventionally defined, the RBE varies as a function of absorbed dose and therefore a single RBE value is limited in its utility because it cannot be used to predict response over a wide range of absorbed doses. Therefore, efforts are underway to standardize bioeffect modeling for different fractionation schemes and dose rates for both nuclear medicine and external beam radiotherapy. Given the preponderant use of external beams of radiation compared to nuclear medicine in cancer therapy, the more clinically relevant quantity, the 2 Gy equieffective dose, EQD2(α/β), has recently been proposed by the ICRU. In concert with EQD2(α/β), we introduce a new, redefined RBE quantity, named RBE2(α/β), as the ratio of the two linear coefficients that characterize the α particle absorbed dose-response curve and the low-LET megavoltage photon 2 Gy fraction equieffective dose-response curve. The theoretical framework for the proposed new formalism is presented along with its application to experimental data obtained from irradiation of a breast cancer cell line. Radiobiological parameters are obtained using the linear quadratic model to fit cell survival data for MDA-MB-231 human breast cancer cells that were irradiated with either α particles or a single fraction of low-LET 137 Cs γ rays. From these, the linear coefficient for both the biologically effective dose (BED) and the EQD2(α/β) response lines were derived for fractionated irradiation. The standard RBE calculation, using the traditional single fraction reference radiation, gave RBE values that ranged from 2.4 for a surviving fraction of 0.82-6.0 for a surviving fraction of 0.02, while the dose-independent RBE2(4.6) value was 4.5 for all surviving fraction values. Furthermore, bioeffect modeling with RBE2(α/β) and EQD2(α/β) demonstrated the capacity to predict the surviving fraction of cells irradiated with acute and fractionated low-LET radiation, α particles and chronic exponentially decreasing dose rates of low-LET radiation. RBE2(α/β) is independent of absorbed dose for α-particle emitters and it provides a more logical framework for data reporting and conversion to equieffective dose than the conventional dose-dependent definition of RBE. Moreover, it provides a much needed foundation for the ongoing development of an α-particle dosimetry paradigm and will facilitate the use of tolerance dose data available from external beam radiation therapy, thereby helping to develop αRPT as a single modality as well as for combination therapies.

Corrosion characteristics of alpha-Ti and Ti2Cu composing Ti-Cu alloys.

PubMed

Takada, Yukyo; Okuno, Osamu

2005-12-01

A series of binary Ti-Cu alloys containing 5-20 mass% Cu was prepared, and the corrosion behavior of alpha-Ti and Ti2Cu composing the Ti-Cu alloys were examined based on the anodic polarization curves and released ions in 0.9% NaCl and 1% lactic acid solutions. In both solutions, the Ti-Cu alloys showed the same anodic polarization curves as titanium in the condition below 1.4 V. However, precipitation of Ti2Cu contributed to a small increase in current densitiy in the transpassive region beyond 1.4 V. The amount of Cu ions released from Ti2Cu was 0.260 and 1.003 (microg/cm2/7 days) in 0.9% NaCl and 1% lactic acid solutions respectively. Although these values were larger than those from alpha-Ti (0.0379 +/- 0.0041 and 0.0962 +/- 0.0327 (microg/cm2/7days) in NaCl and lactic acid solutions respectively), they were not greater than those from type 4 gold alloy under the same conditions.

Targeted inhibition of p38alpha MAPK suppresses tumor-associated endothelial cell migration in response to hypericin-based photodynamic therapy.

PubMed

Hendrickx, Nico; Dewaele, Michael; Buytaert, Esther; Marsboom, Glenn; Janssens, Stefan; Van Boven, Maurits; Vandenheede, Jackie R; de Witte, Peter; Agostinis, Patrizia

2005-11-25

Photodynamic therapy (PDT) is an established anticancer modality and hypericin is a promising photosensitizer for the treatment of bladder tumors. We show that exposure of bladder cancer cells to hypericin PDT leads to a rapid rise in the cytosolic calcium concentration which is followed by the generation of arachidonic acid by phospholipase A2 (PLA2). PLA2 inhibition significantly protects cells from the PDT-induced intrinsic apoptosis and attenuates the activation of p38 MAPK, a survival signal mediating the up-regulation of cyclooxygenase-2 that converts arachidonic acid into prostanoids. Importantly, inhibition of p38alpha MAPK blocks the release of vascular endothelial growth factor and suppresses tumor-promoted endothelial cell migration, a key step in angiogenesis. Hence, targeted inhibition of p38alpha MAPK could be therapeutically beneficial to PDT, since it would prevent COX-2 expression, the inducible release of growth and angiogenic factors by the cancer cells, and cause an increase in the levels of free arachidonic acid, which promotes apoptosis.

Essential role of protein kinase C delta in platelet signaling, alpha IIb beta 3 activation, and thromboxane A2 release.

PubMed

Yacoub, Daniel; Théorêt, Jean-François; Villeneuve, Louis; Abou-Saleh, Haissam; Mourad, Walid; Allen, Bruce G; Merhi, Yahye

2006-10-06

The protein kinase C (PKC) family is an essential signaling mediator in platelet activation and aggregation. However, the relative importance of the major platelet PKC isoforms and their downstream effectors in platelet signaling and function remain unclear. Using isolated human platelets, we report that PKCdelta, but not PKCalpha or PKCbeta, is required for collagen-induced phospholipase C-dependent signaling, activation of alpha(IIb)beta(3), and platelet aggregation. Analysis of PKCdelta phosphorylation and translocation to the membrane following activation by both collagen and thrombin indicates that it is positively regulated by alpha(IIb)beta(3) outside-in signaling. Moreover, PKCdelta triggers activation of the mitogen-activated protein kinase-kinase (MEK)/extracellular-signal regulated kinase (ERK) and the p38 MAPK signaling. This leads to the subsequent release of thromboxane A(2), which is essential for collagen-induced but not thrombin-induced platelet activation and aggregation. This study adds new insight to the role of PKCs in platelet function, where PKCdelta signaling, via the MEK/ERK and p38 MAPK pathways, is required for the secretion of thromboxane A(2).

Thermal emittance from ionization-induced trapping in plasma accelerators

DOE PAGES

Schroeder, C.  B.; Vay, J. -L.; Esarey, E.; ...

2014-10-03

The minimum obtainable transverse emittance (thermal emittance) of electron beams generated and trapped in plasma-based accelerators using laser ionization injection is examined. The initial transverse phase space distribution following ionization and passage through the laser is derived, and expressions for the normalized transverse beam emittance, both along and orthogonal to the laser polarization, are presented. Results are compared to particle-in-cell simulations. Ultralow emittance beams can be generated using laser ionization injection into plasma accelerators, and examples are presented showing normalized emittances on the order of tens of nm.

[The alpha2delta subunit of the voltage-dependent calcium channel. A new pharmaceutical target for psychiatry and neurology].

PubMed

Wedekind, D; Bandelow, B

2005-07-01

Calcium channel blockers are substances used for treating high blood pressure and coronary heart disease. New medications have been developed that modulate calcium channels but also show promise in psychiatric and neurologic applications. Gabapentin and pregabalin bind to a subunit of calcium channels--the alpha2delta receptors--thereby reducing calcium influx to neurons. As a result, less glutamate is released from nerve endings that use excitatory amino acids as transmitters. This in turn reduces substance P-related activation of AMPA heteroreceptors on noradrenergic synapses, total transmitter release, and finally neuronal activity. That mechanism is the probable explanation for gabapentin's and pregabalin's usefulness in the treatment of neuropathic pain but also their possible anticonvulsive and anxiolytic effects.

Investigation of magnetic nanoparticles for the rapid extraction and assay of alpha-emitting radionuclides from urine: Demonstration of a novel radiobioassay method

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

O'Hara, Matthew J.; Carter, Jennifer C.; Maclellan, Jay A.

2011-08-01

In the event of an accidental or intentional release of radionuclides into a populated area, three things must occur in a timely manner: food and drinking water supplies must be determined to be safe to eat / drink, civilians and/or military personnel must be surveyed to ensure that they do not have external contamination, and they must be screened to ensure that significant ingestion or inhalation of radionuclides has not occurred (this paper is concerned with the latter). In the event of such a disaster, the volume of radiobioassays to be performed would be tremendous. If the event released significantmore » levels of β- or α-emitting radionuclides, in vivo assays would be ineffective. Therefore, highly efficient and rapid analytical methods for radionuclide detection from submitted spot urine samples (≤ 50 mL) would be required. At present, the quantitative determination of α-emitting radionuclides from urine samples is highly labor intensive, and requires significant sample preparation and analysis time. Sorbent materials that provide effective collection and enable rapid assay could significantly streamline the radioanalytical process. We have demonstrated the use of paramagnetic nanoparticles as a novel class of extracting media for four α-emitting radionuclides of concern (Po, Ra, Am, and U) from chemically unmodified and pH 2 human urine. Herein the initial experimental sorption results are presented along with a novel method that utilizes paramagnetic nanoparticles for the extraction of radionuclides from unmodified human urine followed by the magnetic field-induced collection of the particles for subsequent α-counting-source preparation. Additionally, we construct a versatile human dose model that determines the detector count times required to estimate internal human dose at specific protective action thresholds. The model provides a means to assess a method’s detection capabilities and use fundamental health physics parameters and actual experimental data as core variables. The modeling shows that with effective sorbent materials, rapid screening for internalized α-emitters is possible from a 50 mL spot urine sample volume collected within one week of exposure/intake.« less

Summaries of Research 1986

DTIC Science & Technology

1986-01-01

PSEUDOMONAS AERUGINOSA AD A177 399 NMRI 86-0009 3CMILLAN M CHERNOW B ROTH BL PHOROOL ESTERS INHIBIT ALPHA I-ADRENERGIC RECEPTOR- STIlULATED...PHORBOL ESTERS PHOSPHOINOSITIDES RATS RECEPTORS, ADRENERGIC, ALPHA TASOMOTOR SYSTEM AD A171 091 NMRI 86-0010 QUESADA M MILLAR DB SMEJKAL R TUEULIN SYNTHESIS...UPTAKE AND RELEASE OF CALCIUM BY BRAIN SYNAPTOSOMES. JOURNAL OF APPLIED PHYSIOLOGY 1966 APR;60(4):1446-50 HYPERBARIC MEDICINE MRO41.O.1.1124 REPORT NO

Assembly of the stator in Escherichia coli ATP synthase. Complexation of alpha subunit with other F1 subunits is prerequisite for delta subunit binding to the N-terminal region of alpha

PubMed Central

Senior, Alan E.; Muharemagi, Alma; Wilke-Mounts, Susan

2008-01-01

Alpha subunit of Escherichia coli ATP synthase was expressed with a C-terminal 6-His tag and purified. Pure alpha was monomeric, competent in nucleotide binding, and had normal N-terminal sequence. In F1-subunit dissociation/reassociation experiments it supported full reconstitution of ATPase, and reassociated complexes were able to bind to F1-depleted membranes with restoration of ATP-driven proton pumping. Therefore interaction between the stator delta subunit and the N-terminal residue 1-22 region of alpha occurred normally when pure alpha was complexed with other F1 subunits. On the other hand, three different types of experiment showed that no interaction occurred between pure delta and isolated alpha subunit. Unlike in F1, the N-terminal region of isolated alpha was not susceptible to trypsin cleavage. Therefore, during assembly of ATP synthase, complexation of alpha subunit with other F1 subunits is prerequisite for delta subunit binding to the N-terminal region of alpha. We suggest that the N-terminal 1-22 residues of alpha are sequestered in isolated alpha until released by binding of beta to alpha subunit. This prevents 1/1 delta/alpha complexes from forming, and provides a satisfactory explanation of the stoichiometry of one delta per three alpha seen in the F1 sector of ATP synthase, assuming that steric hindrance prevents binding of more than one delta to the alpha3/beta3 hexagon. The cytoplasmic fragment of the b subunit (bsol) did not bind to isolated alpha. It might also be that complexation of alpha with beta subunits is prerequisite for direct binding of stator b subunit to the F1-sector. PMID:17176112

Loss of tumorigenic potential by human lung tumor cells in the presence of antisense RNA specific to the ectopically synthesized alpha subunit of human chorionic gonadotropin.

PubMed

Rivera, R T; Pasion, S G; Wong, D T; Fei, Y B; Biswas, D K

1989-06-01

A clonal strain of human lung tumor cells in culture (ChaGo), derived from a bronchogenic carcinoma, synthesizes and secretes large amounts of alpha (alpha) and a comparatively lower level of beta (beta) subunit of the glycoprotein hormone, human chorionic gonadotropin (HCG). ChaGo cells lost their characteristic anchorage-independent growth phenotype in the presence of anti-alpha-HCG antibody. The effect of the antibody was partially reversed by addition of alpha-HCG to the culture medium. ChaGo cells were transfected with an expression vector (pRSV-anti-alpha-HCG), that directs synthesis of RNA complementary to alpha-HCG mRNA. The transfectants produced alpha-HCG antisense RNA which was associated with the reduced level of alpha-HCG. Transfectants also displayed several altered phenotypic properties, including altered morphology, less mitosis, reduced growth rate, loss of anchorage-independent growth, and loss of tumorigenicity in nude mice. Treatment of transfectants with 8,bromo-cAMP resulted in increased accumulation of alpha-HCG mRNA, no change in the level of alpha-HCG antisense RNA, release of the inhibition of [3H]thymidine incorporation, and restoration of anchorage-independent growth phenotype. The overexpression of c-myc, observed in ChaGo cells, was unaffected by the reduced level of alpha-HCG. These results suggest that ectopic synthesis of the alpha subunit of HCG plays a functional role in the transformation of these human lung cells.

AtFXG1, an Arabidopsis gene encoding alpha-L-fucosidase active against fucosylated xyloglucan oligosaccharides.

PubMed

de La Torre, Francisco; Sampedro, Javier; Zarra, Ignacio; Revilla, Gloria

2002-01-01

An alpha-L-fucosidase (EC 3.2.1.51) able to release the t-fucosyl residue from the side chain of xyloglucan oligosaccharides has been detected in the leaves of Arabidopsis plants. Moreover, an alpha-L-fucosidase with similar substrate specificity was purified from cabbage (Brassica oleracea) leaves to render a single band on SDS-PAGE. Two peptide sequences were obtained from this protein band, and they were used to identify an Arabidopsis gene coding for an alpha-fucosidase that we propose to call AtFXG1. In addition, an Arabidopsis gene with homology with known alpha-L-fucosidases has been also found, and we proposed to name it as AtFUC1. Both AtFXG1 and ATFUC1 were heterologously expressed in Pichia pastoris cells and the alpha-L-fucosidase activities secreted to the culture medium. The alpha-L-fucosidase encoded by AtFXG1 was active against the oligosaccharides from xyloglucan XXFG as well as against 2'-fucosyl-lactitol but not against p-nitrophenyl-alpha-L-fucopyranoside. However, the AtFUC1 heterologously expressed was active only against 2'-fucosyl-lactitol. Thus, the former must be related to xyloglucan metabolism.

Tumour necrosis factor alpha changes porcine intestinal ion transport through a paracrine mechanism involving prostaglandins.

PubMed Central

Kandil, H M; Berschneider, H M; Argenzio, R A

1994-01-01

Prostaglandins stimulate electrogenic anion secretion and inhibit sodium chloride absorption in cryptosporidium induced pig diarrhoea. Because tumour necrosis factor alpha (TNF alpha) is an early mediator of inflammation and stimulates prostaglandin secretion, we investigated its effect on intestinal ion transport. Cryptosporidium infected pig ileum showed higher macrophage infiltration and tissue TNF alpha-like activity than uninfected tissues (p < 0.05, n = 4 and p < 0.05, n = 12, respectively). TNF alpha treatment of control porcine ileal mucosa increased the short circuit current (Isc), a measurement of net anion secretion in this model (p < 0.001, n = 23). This effect was blocked by 10(-6) M indomethacin and Cl- replacement. Neither acute treatment nor preincubation of colonic intestinal epithelial cell monolayers (T84) with TNF alpha stimulated the Isc. However, co-mounting of TNF alpha preincubated pig jejunal fibroblasts (P2JF) monolayers back to back with untreated T84 monolayers dose-dependently induced an indomethacin sensitive increase in Isc compared with values in untreated co-mounted monolayers (p < 0.001, n = 11). These data suggest that in infectious diarrhoea, TNF alpha may induce Cl- secretion through a paracrine mechanism involving prostaglandin release from subepithelial cells, for example fibroblasts. PMID:8063221

Endotoxin-induced lethality in neonatal mice is counteracted by interleukin-10 (IL-10) and exacerbated by anti-IL-10.

PubMed Central

Nicoletti, F; Mancuso, G; Ciliberti, F A; Beninati, C; Carbone, M; Franco, S; Cusumano, V

1997-01-01

The lethal effects occurring in neonatal (<24-h-old) BALB/c mice after challenge with 25 mg of lipopolysaccharide (LPS) per kg of body weight were significantly counteracted by pretreatment with recombinant interleukin-10 (rIL-10; 25 or 50 ng/mouse). Concordantly, blockage of endogenous IL-10 with the SXC1 monoclonal antibody increased LPS-induced mortality. Both IL-10 and SXC1 modulated the release of tumor necrosis factor alpha (TNF-alpha) so that, relative to controls, peak TNF-alpha values after LPS challenge were decreased by rIL-10 and increased by anti-IL-10. PMID:9302214

Different signaling pathway between sphingosine-1-phosphate and lysophosphatidic acid in Xenopus oocytes: functional coupling of the sphingosine-1-phosphate receptor to PLC-xbeta in Xenopus oocytes.

PubMed

Noh, S J; Kim, M J; Shim, S; Han, J K

1998-08-01

In Xenopus oocytes, both sphingosine-1-phosphate (S1P) and lysophosphatidic acid (LPA) activate Ca2+-dependent oscillatory Cl- currents by acting through membrane-bound receptors. External application of 50 microM S1P elicited a long-lasting oscillatory current that continued over 30 min from the beginning of oscillation, with 300 nA (n = 11) as a usual maximum peak of current, whereas 1-microM LPA treatment showed only transiently oscillating but more vigorous current responses, with 2,800 nA (n = 18) as a maximum peak amplitude. Both phospholipid-induced Ca2+-dependent Cl- currents were observed in the absence of extracellular Ca2+, were blocked by intracellular injection of the Ca2+ chelator, EGTA, and could not be elicited by treatment with thapsigargin, an inhibitor of endoplasmic reticulum (ER) Ca2+ ATPase. Intracellular Ca2+ release appeared to be from inositol 1,4,5-trisphosphate (IP3)-sensitive Ca2+ store, because Cl- currents were blocked by heparin injection. Pretreatment with the aminosteroid, U-73122, an inhibitor of G protein-mediated phospholipase C (PLC) activation, to oocytes inhibited the current responses evoked both by S1P and LPA. However, when they were injected with 10 ng of antisense oligonucleotide (AS-ODN) against Xenopus phospholipase C (PLC-xbeta), oocytes could not respond to S1P application, whereas they responded normally to LPA, indicating that the S1P signaling pathway goes through PLC-xbeta, whereas LPA signaling goes through another unknown PLC. To determine the types of G proteins involved, we introduced AS-ODNs against four types of G-protein alpha subunits that were identified in Xenopus laevis; G(q)alpha, G11alpha, G0alpha, and G(i1)alpha. Among AS-ODNs against the G alphas tested, AS-G(q)alpha and AS-G(i1)alpha to S1P and AS-G(q)alpha and AS-G11alpha to LPA specifically reduced current responses, respectively, to about 20-30% of controls. These results demonstrate that LPA and S1P, although they have similar structural features, release intracellular Ca2+ from the IP3-sensitive pool, use different components in their signal transduction pathways in Xenopus oocytes.

High performance incandescent lighting using a selective emitter and nanophotonic filters

NASA Astrophysics Data System (ADS)

Leroy, Arny; Bhatia, Bikram; Wilke, Kyle; Ilic, Ognjen; Soljačić, Marin; Wang, Evelyn N.

2017-09-01

Previous approaches for improving the efficiency of incandescent light bulbs (ILBs) have relied on tailoring the emitted spectrum using cold-side interference filters that reflect the infrared energy back to the emitter while transmitting the visible light. While this approach has, in theory, potential to surpass light-emitting diodes (LEDs) in terms of luminous efficiency while conserving the excellent color rendering index (CRI) inherent to ILBs, challenges such as low view factor between the emitter and filter, high emitter (>2800 K) and filter temperatures and emitter evaporation have significantly limited the maximum efficiency. In this work, we first analyze the effect of non-idealities in the cold-side filter, the emitter and the view factor on the luminous efficiency. Second, we theoretically and experimentally demonstrate that the loss in efficiency associated with low view factors can be minimized by using a selective emitter (e.g., high emissivity in the visible and low emissivity in the infrared) with a filter. Finally, we discuss the challenges in achieving a high performance and long-lasting incandescent light source including the emitter and filter thermal stability as well as emitter evaporation.

Close proximity electrostatic effect from small clusters of emitters

NASA Astrophysics Data System (ADS)

Dall'Agnol, Fernando F.; de Assis, Thiago A.

2017-10-01

Using a numerical simulation based on the finite-element technique, this work investigates the field emission properties from clusters of a few emitters at close proximity, by analyzing the properties of the maximum local field enhancement factor (γm ) and the corresponding emission current. At short distances between the emitters, we show the existence of a nonintuitive behavior, which consists of the increasing of γm as the distance c between the emitters decreases. Here we investigate this phenomenon for clusters with 2, 3, 4 and 7 identical emitters and study the influence of the proximity effect in the emission current, considering the role of the aspect ratio of the individual emitters. Importantly, our results show that peripheral emitters with high aspect-ratios in large clusters can, in principle, significantly increase the emitted current as a consequence only of the close proximity electrostatic effect (CPEE). This phenomenon can be seen as a physical mechanism to produce self-oscillations of individual emitters. We discuss new insights for understanding the nature of self-oscillations in emitters based on the CPEE, including applications to nanometric oscillators.

Sharpening of field emitter tips using high-energy ions

DOEpatents

Musket, Ronald G.

1999-11-30

A process for sharpening arrays of field emitter tips of field emission cathodes, such as found in field-emission, flat-panel video displays. The process uses sputtering by high-energy (more than 30 keV) ions incident along or near the longitudinal axis of the field emitter to sharpen the emitter with a taper from the tip or top of the emitter down to the shank of the emitter. The process is particularly applicable to sharpening tips of emitters having cylindrical or similar (e.g., pyramidal) symmetry. The process will sharpen tips down to radii of less than 12 nm with an included angle of about 20 degrees. Because the ions are incident along or near the longitudinal axis of each emitter, the tips of gated arrays can be sharpened by high-energy ion beams rastered over the arrays using standard ion implantation equipment. While the process is particularly applicable for sharpening of arrays of field emitters in field-emission flat-panel displays, it can be effectively utilized in the fabrication of other vacuum microelectronic devices that rely on field emission of electrons.

Comparison of metal release from various metallic biomaterials in vitro.

PubMed

Okazaki, Yoshimitsu; Gotoh, Emiko

2005-01-01

To investigate the metal release of each base and alloying elements in vitro, SUS316L stainless steel, Co-Cr-Mo casting alloy, commercially pure Ti grade 2, and Ti-6Al-4V, V-free Ti-6Al-7Nb and Ti-15Zr-4Nb-4Ta alloys were immersed in various solutions, namely, alpha-medium, PBS(-), calf serum, 0.9% NaCl, artificial saliva, 1.2 mass% L-cysteine, 1 mass% lactic acid and 0.01 mass% HCl for 7d. The difference in the quantity of Co released from the Co-Cr-Mo casting alloy was relatively small in all the solutions. The quantities of Ti released into alpha-medium, PBS(-), calf serum, 0.9% NaCl and artificial saliva were much lower than those released into 1.2% L-cysteine, 1% lactic acid and 0.01% HCl. The quantity of Fe released from SUS316L stainless steel decreased linearly with increasing pH. On the other hand, the quantity of Ti released from Ti materials increased with decreasing pH, and it markedly attenuated at pHs of approximately 4 and higher. The quantity of Ni released from stainless steel gradually decreased with increasing pH. The quantities of Al released from the Ti-6Al-4V and Ti-6Al-7Nb alloys gradually decreased with increasing pH. A small V release was observed in calf serum, PBS(-), artificial saliva, 1% lactic acid, 1.2% l-cysteine and 0.01% HCl. The quantity of Ti released from the Ti-15Zr-4Nb-4Ta alloy was smaller than those released from the Ti-6Al-4V and Ti-6Al-7Nb alloys in all the solutions. In particular, it was approximately 30% or smaller in 1% lactic acid, 1.2% L-cysteine and 0.01% HCl. The quantity of (Zr + Nb + Ta) released was also considerably lower than that of (Al + Nb) or (Al + V) released. Therefore, the Ti-15Zr-4Nb-4Ta alloy with its low metal release in vitro is considered advantageous for long-term implants. Copyright 2004 Elsevier Ltd.

Sodium molybdate prevents hypertension and vascular prostanoid imbalance in fructose-overloaded rats.

PubMed

Peredo, H A; Andrade, V; Donoso, A S; Lee, H J; Puyó, A M

2013-10-01

(1) Fructose (F) overload produces elevated blood pressure (BP), hyperglycaemia, hypertriglyceridemia and insulin resistance, resembling human metabolic syndrome. Previously, we found altered vascular prostanoid (PR) production in this model. (2) Sodium molybdate (Mo), as well as sodium tungstate, causes insulin-like effects and normalizes plasma glucose levels in streptozotocin-treated diabetic rats. We studied the effects of Mo on BP, metabolic parameters and release of PR from the mesenteric vascular bed (MVB) in F-overloaded rats. (3) Four groups of male Sprague-Dawley rats were analysed: Control, tap water to drink; F, F solution 10% W/V to drink; CMo, Mo 100 mg kg day(-1) and FMo, both treatments. After 9 weeks, the animals were killed and MVBs removed and the released PRs measured. (4) F increased BP, glycemia, triglyceridemia and insulinemia. Mo treatment prevented the increases in BP and glycemia, but did not modify triglyceridemia or insulinemia. In addition, Mo decreased BP in controls. (5) Prostaglandins (PG) F2 alpha and E2, PG 6-ketoF1 alpha and thromboxane (TX) B2 , as well as inactive metabolites of prostacyclin (PGI2 ) and TXA2 were detected. F decreased the production of vasodilator PRs PGI2 and PGE2 in MVB. Mo prevented these alterations and increased PGE2 in controls. Vasoconstrict or PRs PGF2 alpha and TXA2 release was not modified. (6) Mo treatment, beyond its known lowering effect on glycemia, prevents the reduction in the vascular release of vasodilator PR observed in this model. This could be one of the mechanisms by which Mo avoids the increase in BP caused by F overload in the rat. © 2013 John Wiley & Sons Ltd.

Role of IL-1 beta and COX2 in silica-induced IL-6 release and loss of pneumocytes in co-cultures.

PubMed

Herseth, Jan I; Refsnes, Magne; Låg, Marit; Schwarze, Per E

2009-10-01

The pro-inflammatory cytokines IL-1 beta, TNF-alpha and IL-6 are of great importance in the development of silica-induced lung damage and repair. In this study we investigated the role of IL-1 beta, TNF-alpha and COX2 in silica-induced regulation of IL-6 release and pneumocyte loss in various mono- and co-cultures of monocytes, pneumocytes and endothelial cells. All co-cultures with monocytes, and especially cultures including endothelial cells, showed an increase of silica-induced release of IL-6 compared to the respective monocultures. Treatment with the antagonist IL-1 ra strongly decreased IL-1 beta and IL-6 release in contact co-cultures of monocytes and pneumocytes. COX2 up-regulation by silica and IL-1 beta was eliminated by IL-1 ra. Inhibition of COX2 markedly reduced both IL-1 beta and IL-6 release. IL-1 ra was more effective than COX2-inhibition in reduction of IL-6, but not of IL-1 beta. Silica-induced pneumocyte loss was reduced by IL-1 beta, but this effect was not counteracted by the IL-1 receptor antagonist. Our findings suggest that silica-induced IL-6 release from pneumocytes is mainly mediated via IL-1 beta release from the monocytes, via both COX2-dependent and -independent pathways. Notably, COX2-derived mediators seem crucial for a positive feed-back regulation of IL-1 beta release from the monocytes. In contrast to silica-induced IL-6, the reduction in pneumocyte loss by IL-1 beta does not seem to be regulated through an IL-1R1-dependent mechanism.

Experimental Study of Coherent Synchrotron Radiation in the Emittance Exchange Line at the A0-Photoinjector

NASA Astrophysics Data System (ADS)

Thangaraj, Jayakar C. T.; Thurman-Keup, R.; Johnson, A.; Lumpkin, A. H.; Edwards, H.; Ruan, J.; Santucci, J.; Sun, Y. E.; Church, M.; Piot, P.

2010-11-01

Next generation accelerators will require a high current, low emittance beam with a low energy spread. Such accelerators will employ advanced beam conditioning systems such as emittance exchangers to manipulate high brightness beams. One of the goals of the Fermilab A0 photoinjector is to investigate the transverse to longitudinal emittance exchange principle. Coherent synchrotron radiation could limit high current operation of the emittance exchanger. In this paper, we report on the preliminary experimental and simulation study of the coherent synchroton radiation (CSR) in the emittance exchange line at the A0 photoinjector.

Synthesis, photophysical and electrochemical properties of a blue emitter with binaphthalene and carbazole units.

PubMed

Guo, Lixia; Wang, Xiaoju; Feng, Liheng

2018-08-05

A blue emitter, 3,3'-(2,2'-dimethoxy-[1,1'-binaphthalene]-6,6'-diyl)bis(9-benzyl-9H-carbazole), was synthesized by Suzuki coupling reaction. The photophysical properties of the emitter in solution were firstly investigated by UV-Vis absorption and fluorescence emission techniques. The results indicate that the emitter has excellent optical and electron transfer properties. The maximum absorption and emission peaks of the emitter are 302 nm and 406 nm with 67.4% fluorescence quantum yield in chloroform, respectively. Thermal stability study reveals that the emitter has a good thermal stability (Td > 330 °C, Tg > 160 °C). Electrochemical Redox properties of the emitters were measured by cyclic voltammetry, and the energy gaps of highest occupied molecular orbital and the lowest unoccupied molecular orbital levels are in good agreement with the results of theoretical calculation. Furthermore, the multilayer electrochemcial device with the emitter was fabricated and its properties were explored. The wavelength of electroluminescence for the device with this emitter locates at 428 nm. These results indicate the emitter as a deep blue-emitting material has promising application in organic light-emitting diode devices. Copyright © 2018 Elsevier B.V. All rights reserved.

Alpha-crystallin-type heat shock proteins: socializing minichaperones in the context of a multichaperone network.

PubMed

Narberhaus, Franz

2002-03-01

Alpha-crystallins were originally recognized as proteins contributing to the transparency of the mammalian eye lens. Subsequently, they have been found in many, but not all, members of the Archaea, Bacteria, and Eucarya. Most members of the diverse alpha-crystallin family have four common structural and functional features: (i) a small monomeric molecular mass between 12 and 43 kDa; (ii) the formation of large oligomeric complexes; (iii) the presence of a moderately conserved central region, the so-called alpha-crystallin domain; and (iv) molecular chaperone activity. Since alpha-crystallins are induced by a temperature upshift in many organisms, they are often referred to as small heat shock proteins (sHsps) or, more accurately, alpha-Hsps. Alpha-crystallins are integrated into a highly flexible and synergistic multichaperone network evolved to secure protein quality control in the cell. Their chaperone activity is limited to the binding of unfolding intermediates in order to protect them from irreversible aggregation. Productive release and refolding of captured proteins into the native state requires close cooperation with other cellular chaperones. In addition, alpha-Hsps seem to play an important role in membrane stabilization. The review compiles information on the abundance, sequence conservation, regulation, structure, and function of alpha-Hsps with an emphasis on the microbial members of this chaperone family.

Targeted drug delivery and enhanced intracellular release using functionalized liposomes

NASA Astrophysics Data System (ADS)

Garg, Ashish

The ability to target cancer cells using an appropriate drug delivery system can significantly reduce the associated side effects from cancer therapies and can help in improving the overall quality of life, post cancer survival. Integrin alpha5beta1 is expressed on several types of cancer cells, including colon cancer and plays an important role in tumor growth and metastasis. Thus, the ability to target the integrin alpha 5beta1 using an appropriate drug delivery nano-vector can significantly help in inhibiting tumor growth and reducing tumor metastasis. The work in this thesis focuses on designing and optimizing, functionalized stealth liposomes (liposomes covered with polyethylene glycol (PEG)) that specifically target the integrin alpha5beta1. The PEG provides a steric barrier allowing the liposomes to circulate in the blood for longer duration and the functionalizing moiety, PR_b peptide specifically recognizes and binds to integrin alpha5beta1 expressing cells. The work demonstrates that by optimizing the amount of PEG and PR_b on the liposomal interface, nano-vectors can be engineered that bind to CT26.WT colon cancer cells in a specific manner and internalize through alpha 5beta1-mediated endocytosis. To further improve the efficacy of the system, PR_b functionalized pH-sensitive stealth liposomes that exhibit triggered release under mild acidic conditions present in endocytotic vesicles were designed. The study showed that PR_b functionalized pH-sensitive stealth liposomes, undergo destabilization under mildly acidic conditions and incorporation of the PR_b peptide does not significantly affect the pH-sensitivity of the liposomes. PR_b functionalized pH-sensitive stealth liposomes bind to CT26.WT colon carcinoma cells that express integrin alpha5beta 1, undergo cellular internalization, and release their load intracellularly in a short period of time as compared to other formulations. PR_b-targeted pH-sensitive stealth liposomes encapsulating 5-fluorouracil (5-FU) show significantly higher cytotoxicity than the PR_b-targeted inert stealth liposomes and the non-targeted stealth liposomes (both pH-sensitive and inert). The studies demonstrated that optimized PR_b functionalized pH sensitive liposomes have the potential to deliver a payload, such as chemotherapeutic agents, directly to colon cancer cells in an efficient and specific manner.

RIP1-mediated mitochondrial dysfunction and ROS production contributed to tumor necrosis factor alpha-induced L929 cell necroptosis and autophagy.

PubMed

Ye, Yuan-Chao; Wang, Hong-Ju; Yu, Lu; Tashiro, Shin-Ichi; Onodera, Satoshi; Ikejima, Takashi

2012-12-01

Tumor necrosis factor alpha (TNFα) induces necroptosis and autophagy; however, the detailed molecular mechanism is not fully understood. In this study, we found that TNFα administration caused mitochondrial dysfunction and reactive oxygen species (ROS) production, which led to necroptosis and autophagy in murine fibrosarcoma L929 cells. Notably, the RIP1 (serine-threonine kinase receptor-interacting protein 1, a main adaptor protein of necroptosis) specific inhibitor necrostatin-1 (Nec-1) recovered mitochondrial dysfunction and ROS production due to TNFα administration. Moreover, pan-caspase inhibitor z-VAD-fmk (zVAD) increased RIP1 expression and exacerbated TNFα-induced mitochondrial dysfunction and ROS production, indicating that RIP1 led to mitochondrial dysfunction and ROS production. In addition, cytochrome c release from mitochondria was accompanied with TNFα administration, and Nec-1 blocked the release of cytochrome c upon TNFα administration, while zVAD enhanced the release. These further suggested that RIP1 induced mitochondrial dysfunction accompanied with cytochrome c release. Furthermore, autophagy inhibitor 3-methyladenine (3MA) did not affect RIP1 expression as well as mitochondrial dysfunction and ROS production. Together with our previous publication that autophagy was a downstream consequence of necroptosis, we concluded that TNFα induced mitochondrial dysfunction accompanied with ROS production and cytochrome c release via RIP1, leading to necroptosis and resulting autophagic cell death. Copyright © 2012 Elsevier B.V. All rights reserved.

Further studies on the effect of nitrogen dioxide on mast cells: The effect of the metabolite, nitrite

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

Fujimaki, Hidekazu; Ozawa, Masashi; Bissonnette, E.

1993-05-01

To evaluate the relationship between atmospheric nitrogen dioxide exposure and the development of allergic diseases, the effects of nitrite as a chemical product of inhaled nitrogen dioxide on mast cell functions were investigated. We have studied nitride-induced histamine release from two functionally distinct mast cell populations, namely peritoneal mast cells (PMC) and intestinal mucosal mast cells (IMMC) of Nippostrongylus brasiliensis-infected rats. High concentrations of nitrite alone (10, 20, and 50 mM) induced histamine release from IMMC, but not from PMC. Moreover, histamine release from PMC and IMMC stimulated with sensitizing antigen was significantly enhanced by pretreatment with 50 mM nitritemore » or nitrate. No differences in histamine release from nitrite-treated and control PMC were seen below 1 mM. To investigate the effect of nitrite on tumor cell cytotoxic activity, PMC were incubated with various concentrations of nitrite. Pretreatment with 5 and 50 mM nitrite markedly depressed tumor necrosis factor (TNF)-[alpha]-dependent natural cytotoxicity of PMC for the tumor target WEHI-164. Thus, high concentrations of nitrite enhanced mast cell histamine release, but depressed TNF-[alpha]-dependent cytotoxicity. However, low concentrations of nitrite (<1 mM) that would normally be produced by short-term atmospheric exposure to nitrogen dioxide may have no significant effects on mast cell functions. 27 refs., 3 figs., 1 tab.« less

Effects of ionotropic glutamate receptor antagonists on rat dural artery diameter in an intravital microscopy model.

PubMed

Chan, K Y; Gupta, S; de Vries, R; Danser, A H J; Villalón, C M; Muñoz-Islas, E; Maassenvandenbrink, A

2010-07-01

During migraine, trigeminal nerves may release calcitonin gene-related peptide (CGRP), inducing cranial vasodilatation and central nociception; hence, trigeminal inhibition or blockade of craniovascular CGRP receptors may prevent this vasodilatation and abort migraine headache. Several preclinical studies have shown that glutamate receptor antagonists affect the pathophysiology of migraine. This study investigated whether antagonists of NMDA (ketamine and MK801), AMPA (GYKI52466) and kainate (LY466195) glutamate receptors affected dural vasodilatation induced by alpha-CGRP, capsaicin and periarterial electrical stimulation in rats, using intravital microscopy. Male Sprague-Dawley rats were anaesthetized and the overlying bone was thinned to visualize the dural artery. Then, vasodilator responses to exogenous (i.v. alpha-CGRP) and endogenous (released by i.v. capsaicin and periarterial electrical stimulation) CGRP were elicited in the absence or presence of the above antagonists. alpha-CGRP, capsaicin and periarterial electrical stimulation increased dural artery diameter. Ketamine and MK801 inhibited the vasodilator responses to capsaicin and electrical stimulation, while only ketamine attenuated those to alpha-CGRP. In contrast, GYKI52466 only attenuated the vasodilatation to exogenous alpha-CGRP, while LY466195 did not affect the vasodilator responses to endogenous or exogenous CGRP. Although GYKI52466 has not been tested clinically, our data suggest that it would not inhibit migraine via vascular mechanisms. Similarly, the antimigraine efficacy of LY466195 seems unrelated to vascular CGRP-mediated pathways and/or receptors. In contrast, the cranial vascular effects of ketamine and MK801 may represent a therapeutic mechanism, although the same mechanism might contribute, peripherally, to cardiovascular side effects.

Amorphous-diamond electron emitter

DOEpatents

Falabella, Steven

2001-01-01

An electron emitter comprising a textured silicon wafer overcoated with a thin (200 .ANG.) layer of nitrogen-doped, amorphous-diamond (a:D-N), which lowers the field below 20 volts/micrometer have been demonstrated using this emitter compared to uncoated or diamond coated emitters wherein the emission is at fields of nearly 60 volts/micrometer. The silicon/nitrogen-doped, amorphous-diamond (Si/a:D-N) emitter may be produced by overcoating a textured silicon wafer with amorphous-diamond (a:D) in a nitrogen atmosphere using a filtered cathodic-arc system. The enhanced performance of the Si/a:D-N emitter lowers the voltages required to the point where field-emission displays are practical. Thus, this emitter can be used, for example, in flat-panel emission displays (FEDs), and cold-cathode vacuum electronics.

Rare Earth Doped Yttrium Aluminum Garnet (YAG) Selective Emitters

NASA Technical Reports Server (NTRS)

Chubb, Donald L.; Pal, AnnaMarie T.; Patton, Martin O.; Jenkins, Phillip P.

1999-01-01

As a result of their electron structure, rare earth ions in crystals at high temperature emit radiation in several narrow bands rather than in a continuous blackbody manner. This study presents a spectral emittance model for films and cylinders of rare earth doped yttrium aluminum garnets. Good agreement between experimental and theoretical film spectral emittances was found for erbium and holmium aluminum garnets. Spectral emittances of films are sensitive to temperature differences across the film. For operating conditions of interest, the film emitter experiences a linear temperature variation whereas the cylinder emitter has a more advantageous uniform temperature. Emitter efficiency is also a sensitive function of temperature. For holminum aluminum garnet film the efficiency is 0.35 at 1446K but only 0.27 at 1270 K.

Method for photon activation positron annihilation analysis

DOEpatents

Akers, Douglas W.

2006-06-06

A non-destructive testing method comprises providing a specimen having at least one positron emitter therein; determining a threshold energy for activating the positron emitter; and determining whether a half-life of the positron emitter is less than a selected half-life. If the half-life of the positron emitter is greater than or equal to the selected half-life, then activating the positron emitter by bombarding the specimen with photons having energies greater than the threshold energy and detecting gamma rays produced by annihilation of positrons in the specimen. If the half-life of the positron emitter is less then the selected half-life, then alternately activating the positron emitter by bombarding the specimen with photons having energies greater then the threshold energy and detecting gamma rays produced by positron annihilation within the specimen.

The characterization of radioactive waste: a critical review of techniques implemented or under development at CEA, France

NASA Astrophysics Data System (ADS)

Pérot, Bertrand; Jallu, Fanny; Passard, Christian; Gueton, Olivier; Allinei, Pierre-Guy; Loubet, Laurent; Estre, Nicolas; Simon, Eric; Carasco, Cédric; Roure, Christophe; Boucher, Lionel; Lamotte, Hervé; Comte, Jérôme; Bertaux, Maïté; Lyoussi, Abdallah; Fichet, Pascal; Carrel, Frédérick

2018-03-01

This review paper describes the destructive and non-destructive measurements implemented or under development at CEA, in view to perform the most complete radioactive waste characterization. First, high-energy photon imaging (radiography, tomography) brings essential information on the waste packages, such as density, position and shape of the waste inside the container and in the possible binder, quality of coating and blocking matrices, presence of internal shields or structures, presence of cracks, voids, or other defects in the container or in the matrix, liquids or other forbidden materials, etc. Radiological assessment is then performed using a series of non-destructive techniques such as gamma-ray spectroscopy, which allows characterizing a wide range of radioactive and nuclear materials, passive neutron coincidence counting and active neutron interrogation with the differential die-away technique, or active photon interrogation with high-energy photons (photofission), to measure nuclear materials. Prompt gamma neutron activation analysis (PGNAA) can also be employed to detect toxic chemicals or elements which can greatly influence the above measurements, such as neutron moderators or absorbers. Digital auto-radiography can also be used to detect alpha and beta contaminated waste. These non-destructive assessments can be completed by gas measurements, to quantify the radioactive and radiolysis gas releases, and by destructive examinations such as coring homogeneous waste packages or cutting the heterogeneous ones, in view to perform visual examination and a series of physical, chemical, and radiochemical analyses on samples. These last allow for instance to check the mechanical and containment properties of the package envelop, or of the waste binder, to measure toxic chemicals, to assess the activity of long-lived radionuclides or pure beta emitters, to determine the isotopic composition of nuclear materials, etc.

Progesterone modulation of alpha5 nAChR subunits influences anxiety-related behavior during estrus cycle.

PubMed

Gangitano, D; Salas, R; Teng, Y; Perez, E; De Biasi, M

2009-06-01

Smokers often report an anxiolytic effect of cigarettes. In addition, stress-related disorders such as anxiety, post-traumatic stress syndrome and depression are often associated with chronic nicotine use. To study the role of the alpha5 nicotinic acetylcholine receptor subunit in anxiety-related responses, control and alpha5 subunit null mice (alpha5(-/-)) were subjected to the open field activity (OFA), light-dark box (LDB) and elevated plus maze (EPM) tests. In the OFA and LDB, alpha5(-/-) behaved like wild-type controls. In the EPM, female alpha5(-/-) mice displayed an anxiolytic-like phenotype, while male alpha5(-/-) mice were undistinguishable from littermate controls. We studied the hypothalamus-pituitary-adrenal axis by measuring plasma corticosterone and hypothalamic corticotropin-releasing factor. Consistent with an anxiolytic-like phenotype, female alpha5(-/-) mice displayed lower basal corticosterone levels. To test whether gonadal steroids regulate the expression of alpha5, we treated cultured NTera 2 cells with progesterone and found that alpha5 protein levels were upregulated. In addition, brain levels of alpha5 mRNA increased upon progesterone injection into ovariectomized wild-type females. Finally, we tested anxiety levels in the EPM during the estrous cycle. The estrus phase (when progesterone levels are low) is anxiolytic-like in wild-type mice, but no cycle-dependent fluctuations in anxiety levels were found in alpha5(-/-) females. Thus, alpha5-containing neuronal nicotinic acetylcholine receptors may be mediators of anxiogenic responses, and progesterone-dependent modulation of alpha5 expression may contribute to fluctuations in anxiety levels during the ovarian cycle.

Characterization and charge distribution of the asparagine-linked oligosaccharides on secreted mouse thyrotropin and free alpha-subunits

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

Gesundheit, N.; Gyves, P.W.; DeCherney, G.S.

1989-06-01

Mouse hemipituitaries in vitro secrete TSH, composed of an alpha-beta heterodimer, as well as excess (free) alpha-subunits. By dual metabolic labeling with (35S)sulfate and (3H)mannose, we have characterized oligosaccharides from secreted TSH alpha, TSH beta, and free alpha-subunits released from the apoprotein by enzymatic deglycosylation. Oligosaccharides from each subunit displayed a distinct anion exchange HPLC profile due to a specific pattern of sialylation and sulfation. Six species were obtained from TSH alpha (with two glycosylation sites), including neutral oligosaccharides as well as those with one or two negative charges. For TSH beta (with one glycosylation site) at least eight oligosaccharidemore » species were noted, representing nearly every permutation of sialylation and sulfation; approximately 30% contained three or more negative charges. Analysis of (3H)mannose-labeled oligosaccharides on Concanavalin-A-agarose showed 85% binding for those from TSH alpha, 70% for free alpha, and 50% for those from TSH beta. These data demonstrate that oligosaccharides from secreted TSH beta were more sialylated and sulfated, consistent with a more complex branching pattern, than those from TSH alpha. Oligosaccharides from free alpha-subunit were more sialylated than those from TSH alpha, and the net negative charge was intermediate between those of TSH alpha and TSH beta. Although great microheterogeneity is present even at the single glycosylation site on the beta-subunit of secreted TSH, a pattern of sialylation and sulfation could be discerned.« less

17{alpha}-Estradiol arrests cell cycle progression at G{sub 2}/M and induces apoptotic cell death in human acute leukemia Jurkat T cells

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

Jun, Do Youn; Park, Hae Sun; Kim, Jun Seok

2008-09-15

A pharmacological dose (2.5-10 {mu}M) of 17{alpha}-estradiol (17{alpha}-E{sub 2}) exerted a cytotoxic effect on human leukemias Jurkat T and U937 cells, which was not suppressed by the estrogen receptor (ER) antagonist ICI 182,780. Along with cytotoxicity in Jurkat T cells, several apoptotic events including mitochondrial cytochrome c release, activation of caspase-9, -3, and -8, PARP degradation, and DNA fragmentation were induced. The cytotoxicity of 17{alpha}-E{sub 2} was not blocked by the anti-Fas neutralizing antibody ZB-4. While undergoing apoptosis, there was a remarkable accumulation of G{sub 2}/M cells with the upregulatoin of cdc2 kinase activity, which was reflected in the Thr56more » phosphorylation of Bcl-2. Dephosphorylation at Tyr15 and phosphorylation at Thr161 of cdc2, and significant increase in the cyclin B1 level were underlying factors for the cdc2 kinase activation. Whereas the 17{alpha}-E{sub 2}-induced apoptosis was completely abrogated by overexpression of Bcl-2 or by pretreatment with the pan-caspase inhibitor z-VAD-fmk, the accumulation of G{sub 2}/M cells significantly increased. The caspase-8 inhibitor z-IETD-fmk failed to influence 17{alpha}-E{sub 2}-mediated caspase-9 activation, but it markedly reduced caspase-3 activation and PARP degradation with the suppression of apoptosis, indicating the contribution of caspase-8; not as an upstream event of the mitochondrial cytochrome c release, but to caspase-3 activation. In the presence of hydroxyurea, which blocked the cell cycle progression at the G{sub 1}/S boundary, 17{alpha}-E{sub 2} failed to induce the G{sub 2}/M arrest as well as apoptosis. These results demonstrate that the cytotoxicity of 17{alpha}-E{sub 2} toward Jurkat T cells is attributable to apoptosis mainly induced in G{sub 2}/M-arrested cells, in an ER-independent manner, via a mitochondria-dependent caspase pathway regulated by Bcl-2.« less

Dopamine-regulated adrenocorticotropic hormone secretion in lactating rats: functional plasticity of melanotropes.

PubMed

Oláh, Márk; Fehér, Pálma; Ihm, Zsófia; Bácskay, Ildikó; Kiss, Timea; Freeman, Marc E; Nagy, Gyorgy M; Vecsernyés, Miklós

2009-01-01

Pro-opiomelanocortin (POMC) is processed to adrenocorticotropic hormone (ACTH) and beta-lipotropin in corticotropes of the anterior lobe, and to alpha-melanocyte-stimulating hormone (alpha-MSH) and beta-endorphin in melanotropes of the intermediate lobe (IL) of the pituitary gland. While ACTH secretion is predominantly under the stimulatory influence of the hypothalamic factors, hormone secretion of the IL is tonically inhibited by neuroendocrine dopamine (NEDA) neurons. Lobe-specific POMC processing is not absolute. For example, D(2) type DA receptor (D2R)-deficient mice have elevated plasma ACTH levels, although it is known that corticotropes do not express D2R(s). Moreover, observations that suckling does not influence alpha-MSH release, while it induces an increase in plasma ACTH is unexplained. The aim of the present study was to investigate the involvement of the NEDA system in the regulation of ACTH secretion and the participation of the IL in ACTH production in lactating rats. Untreated and estradiol (E(2))-substituted ovariectomized (OVX) females were also studied. The concentration of ACTH in the IL was higher in lactating rats than in OVX rats, while the opposite change in alpha-MSH level of the IL was observed. DA levels in the IL and the neural lobe were lower in lactating rats than in OVX rats. Suckling-induced ACTH response was eliminated by pretreatment with the DA receptor agonist, bromocriptine (BRC). Inhibition of DA biosynthesis by alpha-methyl-p-tyrosine (alphaMpT) and blockade of D2R by domperidone (DOM) elevated plasma ACTH levels, but did not influence plasma alpha-MSH levels in lactating rats. The same drugs had opposite effects in OVX and OVX + E(2) animals. In lactating mothers, BRC was able to block ACTH responses induced by both alphaMpT and DOM. Surgical denervation of the IL elevated basal plasma levels of ACTH. Taken together, these data indicate that melanotropes synthesize ACTH during lactation and its release from these cells is regulated by NEDA neurons. Copyright 2009 S. Karger AG, Basel.

Monte Carlo simulation of age-dependent radiation dose from alpha- and beta-emitting radionuclides to critical trabecular bone and bone marrow targets

NASA Astrophysics Data System (ADS)

Dant, James T.; Richardson, Richard B.; Nie, Linda H.

2013-05-01

Alpha (α) particles and low-energy beta (β) particles present minimal risk for external exposure. While these particles can induce leukemia and bone cancer due to internal exposure, they can also be beneficial for targeted radiation therapies. In this paper, a trabecular bone model is presented to investigate the radiation dose from bone- and marrow-seeking α and β emitters to different critical compartments (targets) of trabecular bone for different age groups. Two main issues are addressed with Monte Carlo simulations. The first is the absorption fractions (AFs) from bone and marrow to critical targets within the bone for different age groups. The other issue is the application of 223Ra for the radiotherapy treatment of bone metastases. Both a static model and a simulated bone remodeling process are established for trabecular bone. The results show significantly lower AFs from radionuclide sources in the bone volume to the peripheral marrow and the haematopoietic marrow for adults than for newborns and children. The AFs from sources on the bone surface and in the bone marrow to peripheral marrow and haematopoietic marrow also varies for adults and children depending on the energy of the particles. Regarding the use of 223Ra as a radionuclide for the radiotherapy of bone metastases, the simulations show a significantly higher dose from 223Ra and its progeny in forming bone to the target compartment of bone metastases than that from two other more commonly used β-emitting radiopharmaceuticals, 153Sm and 89Sr. There is also a slightly lower dose from 223Ra in forming bone to haematopoietic marrow than that from 153Sm and 89Sr. These results indicate a higher therapy efficiency and lower marrow toxicity from 223Ra and its progeny. In conclusion, age-related changes in bone dimension and cellularity seem to significantly affect the internal dose from α and β emitters in the bone and marrow to critical targets, and 223Ra may be a more efficient radiopharmaceutical for the treatment of bone metastases than 153Sm and 89Sr, if the diffusion of 219Rn to the bone marrow is insignificant.

Can Gas Outflows Explain The Strong Lyα Emission Of Lyman Alpha Emitters?

NASA Astrophysics Data System (ADS)

Hashimoto, Takuya; Ouchi, M.; Shimasaku, K.; Nakajima, K.; Ono, Y.; Rauch, M.

2012-05-01

Lyman alpha emitters (LAEs) are galaxies commonly seen at high redshift, probably playing an important role in galaxy evolution as building blocks of massive galaxies. The most interesting feature of LAEs is strong Lyα emission, because Lyα photons produced in a galaxy are expected to be easily absorbed by dust in the ISM before escaping the galaxy due to their resonant nature. Previous studies have suggested that outflow may help their escape thanks to reduced cross sections of outflowing (ie, redshifted) neutral hydrogen atoms. Although the presence of outflows can be examined from the offset of the Lyα emission from the systemic velocity defined by Hα emission, there are only four LAEs with reliable detection of Hα emission. We present the results of Magellan/MMIRS and Keck/NIRSPEC spectroscopic observations of five LAEs at z˜2.2 from our wide-field narrow-band survey with Subaru/Suprime-Cam. We successfully detect Hα emission for five objects. After eliminating an AGN contaminated object, we measure the velocityoffset between Lyα and Hα (Δ v_Lyα) for the remaining four, to find that three have a positive offset, suggesting an outflow. Since three among the four from the the literature also have an outflow, we conclude that ˜75% of LAEs have an outflow, with velocities of 75-280 km/s. We then use these eight LAEs to examine how the Lyα strength defined by Lyα escape fraction (f_esc) and/or Lyα equivalent width (EW(Lyα)) depend on other physical quantities including those derived from SED fitting. Contrary to our expectation, we find that both f_esc and EW(Lyα) decrease with Δ v_Lyα. Thus, although LAEs do have outflow, high outflow velocities are not the primary cause of strong Lyα emission. We also find that the Lyα strength does not depend on E(B-V). However, we find that objects with a clumpier gas distribution may have higher f_esc.

The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP)

NASA Technical Reports Server (NTRS)

Ishikawa, Shin-nosuke; Kano, R.; Kobayashi, K.; Bando, T.; Narukage, N..; Ishikawa, R.; Kubo, M.; Katsukawa, Y.; Suematsu, Y.; Hara, H.;

Emittance Measurements Relevant to a 250 W(sub t) Class RTPV Generator for Space Exploration

NASA Technical Reports Server (NTRS)

Wolford, Dave; Chubb, Donald; Clark, Eric; Pal, Anna Maria; Scheiman, Dave; Colon, Jack

2009-01-01

A proposed 250 Wt Radioisotope Thermophotovoltaic (RTPV) power system for utilization in lunar exploration and the subsequent exploration of Mars is described. Details of emitter selection are outlined for use in a maintenance free power supply that is productive over a 14-year mission life. Thorough knowledge of a material s spectral emittance is essential for accurate modeling of the RTPV system. While sometimes treated as a surface effect, emittance involves radiation from within a material. This creates a complex thermal gradient which is a combination of conductive and radiative heat transfer mechanisms. Emittance data available in the literature is a valuable resource but it is particular to the test sample s physical characteristics and the test environment. Considerations for making spectral emittance measurements relevant to RTPV development are discussed. Measured spectral emittance data of refractory emitter materials is given. Planned measurement system modifications to improve relevance to the current project are presented.

Selective far-field addressing of coupled quantum dots in a plasmonic nanocavity.

PubMed

Tang, Jianwei; Xia, Juan; Fang, Maodong; Bao, Fanglin; Cao, Guanjun; Shen, Jianqi; Evans, Julian; He, Sailing

2018-04-27

Plasmon-emitter hybrid nanocavity systems exhibit strong plasmon-exciton interactions at the single-emitter level, showing great potential as testbeds and building blocks for quantum optics and informatics. However, reported experiments involve only one addressable emitting site, which limits their relevance for many fundamental questions and devices involving interactions among emitters. Here we open up this critical degree of freedom by demonstrating selective far-field excitation and detection of two coupled quantum dot emitters in a U-shaped gold nanostructure. The gold nanostructure functions as a nanocavity to enhance emitter interactions and a nanoantenna to make the emitters selectively excitable and detectable. When we selectively excite or detect either emitter, we observe photon emission predominantly from the target emitter with up to 132-fold Purcell-enhanced emission rate, indicating individual addressability and strong plasmon-exciton interactions. Our work represents a step towards a broad class of plasmonic devices that will enable faster, more compact optics, communication and computation.

Benchmarking of measurement and simulation of transverse rms-emittance growth

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

Jeon, Dong-O

2008-01-01

Transverse emittance growth along the Alvarez DTL section is a major concern with respect to the preservation of beam quality of high current beams at the GSI UNILAC. In order to define measures to reduce this growth appropriated tools to simulate the beam dynamics are indispensable. This paper is about the benchmarking of three beam dynamics simulation codes, i.e. DYNAMION, PARMILA, and PARTRAN against systematic measurements of beam emittances for different machine settings. Experimental set-ups, data reduction, the preparation of the simulations, and the evaluation of the simulations will be described. It was found that the measured 100%-rmsemittances behind themore » DTL exceed the simulated values. Comparing measured 90%-rms-emittances to the simulated 95%-rms-emittances gives fair to good agreement instead. The sum of horizontal and vertical emittances is even described well by the codes as long as experimental 90%-rmsemittances are compared to simulated 95%-rms-emittances. Finally, the successful reduction of transverse emittance growth by systematic beam matching is reported.« less

Emitter utilization in heterojunction bipolar transistors

NASA Astrophysics Data System (ADS)

Quach, T.; Jenkins, T.; Barrette, J.; Bozada, C.; Cerny, C.; Desalvo, G.; Dettmer, R.; Ebel, J.; Gillespie, J.; Havasy, C.; Ito, C.; Nakano, K.; Pettiford, C.; Sewell, J.; Via, D.; Anholt, R.

1997-09-01

We compare measured collector current densities, cutoff frequencies ( ft), and transducer gains for thermally shunted heterojunction bipolar transistors with 2-16 μm emitter dot diameters or 2-8 μm emitter bar widths with models of the emitter utilization factors. Models that do not take emitter resistance into account predict that the d.c. utilization factors are below 0.7 for collector current densities greater than 6 × 10 4 A cm -2 and emitter diameters or widths greater than 8 μm. However, because the current gains are compressed by the emitter resistances at those current densities, the measured utilization factors are close to 1, which agrees with models that include emitter resistance. A.c. utilization factors are evident in the transistor Y parameters. For example, Re|Y 21z.sfnc drops off at high frequencies more steeply in HBTs with large emitter diameters or widths than in small ones. However, measured data shows that the HBT a.c. current gains h21 or ft values are not influenced by the a.c. utilization factor. A.c. utilization effects on HBT performance parameters such as small signal and power gains, output power, and power added efficiency are also examined.

Exogenous NO administration and alpha-adrenergic vasoconstriction in human limbs.

PubMed

Rosenmeier, Jaya B; Fritzlar, Sandy J; Dinenno, Frank A; Joyner, Michael J

2003-12-01

Nitric oxide (NO) is capable of blunting alpha-adrenergic vasoconstriction in contracting skeletal muscles of experimental animals (functional sympatholysis). We therefore tested the hypothesis that exogenous NO administration can blunt alpha-adrenergic vasoconstriction in resting human limbs by measuring forearm blood flow (FBF; Doppler ultrasound) and blood pressure in eight healthy males during brachial artery infusions of three alpha-adrenergic constrictors (tyramine, which evokes endogenous norepinephrine release; phenylephrine, an alpha1-agonist; and clonidine, an alpha2-agonist). To simulate exercise hyperemia, the vasoconstriction caused by the alpha-agonists was compared during adenosine-mediated (>50% NO independent) and sodium nitroprusside-mediated (SNP; NO donor) vasodilation of the forearm. Both adenosine and SNP increased FBF from approximately 35-40 to approximately 200-250 ml/min. All three alpha-adrenergic constrictor drugs caused marked reductions in FBF and calculated forearm vascular conductance (P < 0.05). The relative reductions in forearm vascular conductance caused by the alpha-adrenergic constrictors during SNP infusion were similar (tyramine, -74 +/- 3 vs. -65 +/- 2%; clonidine, -44 +/- 6 vs. -44 +/- 6%; P > 0.05) or slightly greater (phenylephrine, -47 +/- 6 vs. -33 +/- 6%; P < 0.05) compared with the responses during adenosine. In conclusion, these results indicate that exogenous NO sufficient to raise blood flow to levels simulating those seen during exercise does not blunt alpha-adrenergic vasoconstriction in the resting human forearm.

Partial agonist clonidine mediates alpha(2)-AR subtypes specific regulation of cAMP accumulation in adenylyl cyclase II transfected DDT1-MF2 cells.

PubMed

Limon-Boulez, I; Bouet-Alard, R; Gettys, T W; Lanier, S M; Maltier, J P; Legrand, C

2001-02-01

alpha2-Adrenergic receptor (alpha(2)-AR) activation in the pregnant rat myometrium at midterm potentiates beta(2)-AR stimulation of adenylyl cyclase (AC) via Gbetagamma regulation of the type II isoform of adenylyl cyclase. However, at term, alpha(2)-AR activation inhibits beta(2)-AR stimulation of AC. This phenomenon is associated with changes in alpha(2)-AR subtype expression (midterm alpha(2A/D)-AR > alpha(2B)-AR; term alpha(2B) >or =alpha(2A/D)-AR), without any change in ACII mRNA, suggesting that alpha(2A/D)- and alpha(2B)-AR differentially regulate beta(2)-cAMP production. To address this issue, we have stably expressed the same density of alpha(2A/D)- or alpha(2B)-AR with AC II in DDT1-MF2 cells. Clonidine (partial agonist) increased beta(2)-AR-stimulated cAMP production in alpha(2A/D)-AR-ACII transfectants but inhibited it in alpha(2B)-AR-ACII transfectants. In contrast, epinephrine (full agonist) enhanced beta(2)-stimulated ACII in both alpha(2A)- and alpha(2B)-ACII clonal cell lines. 4-Azidoanilido-[alpha-(32)P]GTP-labeling of activated G proteins indicated that, in alpha(2B)-AR transfectants, clonidine activated only Gi(2), whereas epinephrine, the full agonist, effectively coupled to Gi(2) and Gi(3). Thus, partial and full agonists selectively activate G proteins that lead to drug specific effects on effectors. Moreover, these data indicate that Gi(3) activation is required for potentiation of beta(2)-AR stimulation of AC by alpha(2A/D) and alpha(2B)-AR in DDT1-MF2 cells. This may reflect an issue of the amount of Gbetagamma released upon receptor activation and/or betagamma composition of Gi(3) versus Gi(2).

Radiosensitivity of Prostate Cancer Cell Lines for Irradiation from Beta Particle-emitting Radionuclide ¹⁷⁷Lu Compared to Alpha Particles and Gamma Rays.

PubMed

Elgqvist, Jörgen; Timmermand, Oskar Vilhelmsson; Larsson, Erik; Strand, Sven-Erik

2016-01-01

The purpose of the present study was to investigate the radiosensitivity of the prostate cancer cell lines LNCaP, DU145, and PC3 when irradiated with beta particles emitted from (177)Lu, and to compare the effect with irradiation using alpha particles or gamma rays. Cells were irradiated with beta particles emitted from (177)Lu, alpha particles from (241)Am, or gamma rays from (137)Cs. A non-specific polyclonal antibody was labeled with (177)Lu and used to irradiate cells in suspension with beta particles. A previously described in-house developed alpha-particle irradiator based on a (241)Am source was used to irradiate cells with alpha particles. External gamma-ray irradiation was achieved using a standard (137)Cs irradiator. Cells were irradiated to absorbed doses equal to 0, 0.5, 1, 2, 4, 6, 8, or 10 Gy. The absorbed doses were calculated as mean absorbed doses. For evaluation of cell survival, the tetrazolium-based WST-1 assay was used. After irradiation, WST-1 was added to the cell solutions, incubated, and then measured for level of absorbance at 450 nm, indicating the live and viable cells. LNCaP, DU145, and PC3 cell lines all had similar patterns of survival for the different radiation types. No significant difference in surviving fractions were observed between cells treated with beta-particle and gamma-ray irradiation, represented for example by the surviving fraction values (mean±SD) at 2, 6, and 10 Gy (SF2, SF6, and SF10) for DU145 after beta-particle irradiation: 0.700±0.090, 0.186±0.050 and 0.056±0.010, respectively. A strong radiosensitivity to alpha particles was observed, with SF2 values of 0.048±0.008, 0.018±0.006 and 0.015±0.005 for LNCaP, DU145, and PC3, respectively. The surviving fractions after irradiation using beta particles or gamma rays did not differ significantly at the absorbed dose levels and dose rates used. Irradiation using alpha particles led to a high level of cell killing. The results show that the beta-particle emitter (177)Lu as well as alpha-particles are both good candidates for radionuclide-therapy applications in the treatment of prostate cancer. Copyright© 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Ion Motion Induced Emittance Growth of Matched Electron Beams in Plasma Wakefields.

PubMed

An, Weiming; Lu, Wei; Huang, Chengkun; Xu, Xinlu; Hogan, Mark J; Joshi, Chan; Mori, Warren B

2017-06-16

Plasma-based acceleration is being considered as the basis for building a future linear collider. Nonlinear plasma wakefields have ideal properties for accelerating and focusing electron beams. Preservation of the emittance of nano-Coulomb beams with nanometer scale matched spot sizes in these wakefields remains a critical issue due to ion motion caused by their large space charge forces. We use fully resolved quasistatic particle-in-cell simulations of electron beams in hydrogen and lithium plasmas, including when the accelerated beam has different emittances in the two transverse planes. The projected emittance initially grows and rapidly saturates with a maximum emittance growth of less than 80% in hydrogen and 20% in lithium. The use of overfocused beams is found to dramatically reduce the emittance growth. The underlying physics that leads to the lower than expected emittance growth is elucidated.

Flavonoids inhibit histamine release and expression of proinflammatory cytokines in mast cells.

PubMed

Park, Hyo-Hyun; Lee, Soyoung; Son, Hee-Young; Park, Seung-Bin; Kim, Mi-Sun; Choi, Eun-Ju; Singh, Thoudam S K; Ha, Jeoung-Hee; Lee, Maan-Gee; Kim, Jung-Eun; Hyun, Myung Chul; Kwon, Taeg Kyu; Kim, Yeo Hyang; Kim, Sang-Hyun

2008-10-01

Mast cells participate in allergy and inflammation by secreting inflammatory mediators such as histamine and proinflammatory cytokines. Flavonoids are naturally occurring molecules with antioxidant, cytoprotective, and antiinflammatory actions. However, effect of flavonoids on the release of histamine and proinflammatory mediator, and their comparative mechanism of action in mast cells were not well defined. Here, we compared the effect of six flavonoids (astragalin, fisetin, kaempferol, myricetin, quercetin, and rutin) on the mast cell-mediated allergic inflammation. Fisetin, kaempferol, myricetin, quercetin, and rutin inhibited IgE or phorbol-12-myristate 13-acetate and calcium ionophore A23187 (PMACI)-mediated histamine release in RBL-2H3 cells. These five flavonoids also inhibited elevation of intracellular calcium. Gene expressions and secretion of proinflammatory cytokines such as tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1beta, IL-6, and IL-8 were assessed in PMACI-stimulated human mast cells (HMC-1). Fisetin, quercetin, and rutin decreased gene expression and production of all the proinflammatory cytokines after PMACI stimulation. Myricetin attenuated TNF-alpha and IL-6 but not IL-1beta and IL-8. Fisetin, myricetin, and rutin suppressed activation of NF-kappaB indicated by inhibition of nuclear translocation of NF-kappaB, NF-kappaB/DNA binding, and NF-kappaB-dependent gene reporter assay. The pharmacological actions of these flavonoids suggest their potential activity for treatment of allergic inflammatory diseases through the down-regulation of mast cell activation.

Effects of long-term lithium and desipramine treatment upon clonidine-induced inhibition of /sup 3/H-norepinephrine release from rat hippocampal slices

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

Spengler, R.N.; Hollingsworth, P.J.; Smith, C.B.

1986-03-01

Long-term treatment with antidepressant agents alters the specific binding of /sup 3/H-clonidine, an alpha/sub 2/ adrenoreceptor agonist, to neural membranes isolated from specific areas of the rat brain. The purpose of the present study was to determine whether these changes in binding of /sup 3/H-clonidine represent an alteration in the functional state of the presynaptic alpha/sub 2/ adrenorecepotr. Hippocampal slices were incubated with /sup 3/H-norepinephrine (/sup 3/H-NE, 330 nM0 for 20 min, washed with fresh buffer for 30 min and then stimulated (4 Hz, 2 msec duration, 2 min) at 12 min intervals. Cumulative concentration-effect curves were determined of /supmore » 3/H-NE. Rats were injected, i.p., twice daily for 14 days with lithium chloride (105 mg/kg), desipramine HCl (10 mg/kg) or saline. In controls, the EC50 for clonidine was 2.3 +/- 1.0 nM (n = 3). After lithium treatment, the clonidine concentration-effect curve was shifted to the right, and the EC50 as 12.1 +/- 4.3 nM. Desipramine treatment nearly abolished the inhibitory effect of clonidine upon the release of /sup 3/H-NE by field stimulation. These observations indicate that the long-term administration of desipramine and lithium produce a functional subsensitivity of the alpha/sub 2/ adrenoreceptor which regulates norepinephrine release in the rat brain.« less

Beyond injection: Trojan horse underdense photocathode plasma wakefield acceleration

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

Hidding, B.; Rosenzweig, J. B.; Xi, Y.

2012-12-21

An overview on the underlying principles of the hybrid plasma wakefield acceleration scheme dubbed 'Trojan Horse' acceleration is given. The concept is based on laser-controlled release of electrons directly into a particle-beam-driven plasma blowout, paving the way for controlled, shapeable electron bunches with ultralow emittance and ultrahigh brightness. Combining the virtues of a low-ionization-threshold underdense photocathode with the GV/m-scale electric fields of a practically dephasing-free beam-driven plasma blowout, this constitutes a 4th generation electron acceleration scheme. It is applicable as a beam brightness transformer for electron bunches from LWFA and PWFA systems alike. At FACET, the proof-of-concept experiment 'E-210: Trojanmore » Horse Plasma Wakefield Acceleration' has recently been approved and is in preparation. At the same time, various LWFA facilities are currently considered to host experiments aiming at stabilizing and boosting the electron bunch output quality via a trojan horse afterburner stage. Since normalized emittance and brightness can be improved by many orders of magnitude, the scheme is an ideal candidate for light sources such as free-electron-lasers and those based on Thomson scattering and betatron radiation alike.« less

Prototype of a subsurface drip irrigation emitter: Manufacturing, hydraulic evaluation and experimental analyses

NASA Astrophysics Data System (ADS)

Souza, Wanderley De Jesus; Rodrigues Sinobas, Leonor; Sánchez, Raúl; Arriel Botrel, Tarlei; Duarte Coelho, Rubens

2013-04-01

Root and soil intrusion into the conventional emitters is one of the major disadvantages to obtain a good uniformity of water application in subsurface drip irrigation (SDI). In the last years, there have been different approaches to reduce these problems such as the impregnation of emitters with herbicide, and the search for an emitter geometry impairing the intrusion of small roots. Within the last this study, has developed and evaluated an emitter model which geometry shows specific physical features to prevent emitter clogging. This work was developed at the Biosystems Engineering Department at ESALQ-USP/Brazil, and it is a part of a research in which an innovated emitteŕs model for SDI has been developed to prevent root and soil particles intrusion. An emitter with a mechanical-hydraulic mechanism (opening and closing the water outlet) for SDI was developed and manufactured using a mechanical lathe process. It was composed by a silicon elastic membrane a polyethylene tube and a Vnyl Polychloride membrane protector system. In this study the performance of the developed prototype was assessed in the laboratory and in the field conditions. In the laboratory, uniformity of water application was calculated by the water emission uniformity coefficient (CUE), and the manufacturer's coefficient of variation (CVm). In addition, variation in the membrane diameter submitted to internal pressures; head losses along the membrane, using the energy equation; and, precision and accuracy of the equation model, analyzed by Pearson's correlation coefficient (r), and by Willmott's concordance index (d) were also calculated with samples of the developed emitters. In the field, the emitters were installed in pots with and without sugar cane culture from October 2010 to January 2012. During this time, flow rate in 20 emitters were measured periodically, and the aspects of them about clogging at the end of the experiment. Emitters flow rates were measured quarterly to calculate: relative flow rate (QR); flow disturbance (FD); CUE; and, variation coefficient of relative flow (CVQR). In the laboratory, both "CVm" and "CUE" were small since emitters were manufactured manually, the manufacturing variation was higher than in processed emitters. Variation in the membrane diameter decreased 1/4.5 from the central toward to the emitter end; and, the head loss increased. Estimated pressures were in good agreement to the observed ones with r and d values of 0.95, and 0.85, respectively. In the field tests, coefficients CVQR and QR were variable showing a poor classification according with ABNT (1986) and Solomon (1984). FD values were ranged between 11 and 24%and there was no observed clogging by roots and/or soil intrusion at the end of the experiment. On the other hand, emitter's flows were close to the average, indicating that water application kept according to the initial results. This study shows the suitability of this emitter model to prevent root and soil intrusion within the research conditions however further studies would be needed assessing the membrane performance, emitter physical characteristics, and control of emitter flow rate in order to develop the final prototype.

Fault location in optical networks

DOEpatents

Stevens, Rick C [Apple Valley, MN; Kryzak, Charles J [Mendota Heights, MN; Keeler, Gordon A [Albuquerque, NM; Serkland, Darwin K [Albuquerque, NM; Geib, Kent M [Tijeras, NM; Kornrumpf, William P [Schenectady, NY

2008-07-01

One apparatus embodiment includes an optical emitter and a photodetector. At least a portion of the optical emitter extends a radial distance from a center point. The photodetector provided around at least a portion of the optical emitter and positioned outside the radial distance of the portion of the optical emitter.

Monoamine oxidase and head-twitch response in mice. Mechanisms of alpha-methylated substrate derivatives.

PubMed

Nakagawasai, Osamu; Arai, Yuichiro; Satoh, Shin-etsu; Satoh, Nobunori; Neda, Mitsuro; Hozumi, Masato; Oka, Ryusho; Hiraga, Hajime; Tadano, Takeshi

2004-01-01

It is well known that head-twitch response (HTR) in mice represents hallucinations, since administration of lysergic acid diethylamide (LSD) produces hallucinations in humans, and the HTR in mice is induced by administration of LSD as a hallucinogen. The HTR is produced by excitation of 5-hydroxytryptamine (5-HT)2A receptors. In this paper, we review the mechanisms of HTR induced by various drugs such as 5-HT precursor, 5-HT receptor agonist, 5-HT releaser, hallucinogenic compounds, benzodiazepins and cannabinoid. The response induced by HTR-inducers is significantly enhanced by combined treatment with a non-selective form of monoamine oxidase (MAO) inhibitor. Thus, the relationship between MAO activity and HTR caused by these drugs (especially, alpha-methylated analogous compounds which 5-fluoro-alpha-methyltryptamine, 6-fluoro-alpha-methyltryptamine and p-hydroxyamphetamine) is presented in detail.

Distinct expression pattern of IFN-alpha and TNF-alpha in juvenile idiopathic arthritis synovial tissue.

PubMed

Gattorno, M; Chicha, L; Gregorio, A; Ferlito, F; Rossi, F; Jarrossay, D; Lanzavecchia, A; Martini, A; Manz, M G

2007-04-01

Recent laboratory and clinical data suggest that two prototype autoimmune diseases, systemic lupus erythematosus and rheumatoid arthritis are mainly driven by distinct cytokines, interferon (IFN)-alpha and tumour necrosis factor (TNF)-alpha, respectively. We here investigated the presence and characteristics of natural type I IFN-producing cells (IPCs), as well as IFN-alpha and TNF-alpha expression at sites of inflammation in juvenile idiopathic arthritis (JIA). Peripheral blood (PB) and synovial fluid (SF) mononuclear cells (MNCs) (n = 25 each) from JIA patients with active disease were studied. IPCs were identified as BCDA-2(+)CD123(+)HLA-DR(+)CD45RA(+) cells, and dendritic cells (DCs) as CD11c(+)CD14(-/low)lin(-) cells by flow cytometry. IPCs and DCs were analysed for Toll-like receptor-7 and -9 mRNA expression by real-time polymerase chain reaction. IFN-alpha was measured by enzyme-linked immunosorbent assay in serum, SF and in supernatants of influenza virus-infected, cultured IPCs. Synovial tissues of n = 6 additional JIA patients were analysed by immunohistochemistry using mAbs against CD123, IFN-alpha, TNF-alpha, CD3, CD19 and CD138. IPCs were enriched in SF MNCs compared with PB MNCs in all JIA patients. Influenza-induced, but no spontaneous IFN-alpha release was detected from SF IPCs, and serum and SF IFN-alpha levels were not elevated. Nonetheless, in synovial tissue IFN-alpha producing cells accumulated at inflammatory lymph-follicular-like structures, while TNF-alpha producing cells were mostly found at the lining and sublining layers. These data suggest that besides TNF-alpha-expressing cells, IFN-alpha-producing IPCs are involved in initiation, maintenance or regulation of the inflammatory response in JIA.

Hybrid emitter all back contact solar cell

DOEpatents

Loscutoff, Paul; Rim, Seung

2016-04-12

An all back contact solar cell has a hybrid emitter design. The solar cell has a thin dielectric layer formed on a backside surface of a single crystalline silicon substrate. One emitter of the solar cell is made of doped polycrystalline silicon that is formed on the thin dielectric layer. The other emitter of the solar cell is formed in the single crystalline silicon substrate and is made of doped single crystalline silicon. The solar cell includes contact holes that allow metal contacts to connect to corresponding emitters.

Tumor Necrosis Factor alpha (TNF{alpha}) regulates CD40 expression through SMAR1 phosphorylation

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

Singh, Kamini; Sinha, Surajit; Malonia, Sunil Kumar

2010-01-08

CD40 plays an important role in mediating inflammatory response and is mainly induced by JAK/STAT phosphorylation cascade. TNF{alpha} is the key cytokine that activates CD40 during inflammation and tumorigenesis. We have earlier shown that SMAR1 can repress the transcription of Cyclin D1 promoter by forming a HDAC1 dependent repressor complex. In this study, we show that SMAR1 regulates the transcription of NF-{kappa}B target gene CD40. SMAR1 recruits HDAC1 and forms a repressor complex on CD40 promoter and keeps its basal transcription in check. Further, we show that TNF{alpha} stimulation induces SMAR1 phosphorylation at Ser-347 and promotes its cytoplasmic translocation, thusmore » releasing its negative effect. Concomitantly, TNF{alpha} induced phosphorylation of STAT1 at Tyr-701 by JAK1 facilitates its nuclear translocation and activation of CD40 through p300 recruitment and core Histone-3 acetylation. Thus, TNF{alpha} mediated regulation of CD40 expression occurs by dual phosphorylation of SMAR1 and STAT1.« less

A rational approach to predict and modulate stereolability of chiral alpha substituted ketones.

PubMed

Cirilli, Roberto; Costi, Roberta; Di Santo, Roberto; Gasparrini, Francesco; La Torre, Francesco; Pierini, Marco; Siani, Gabriella

2009-01-01

An effective strategy to assess and modulate the stereolability of chiral alpha substituted ketones (C alpha SKs) is presented. The tendency of C alpha SKs to retain or change their configuration in water is analyzed as a function of thermodynamic proton-release attitude of alpha asymmetric atoms inside the structures by linear Brønsted correlations. A molecular modeling procedure was developed to analyze and suggest chemical modifications of C alpha SKs in view to obtain the desired grade of stereochemical stability. The approach was employed to predict the tendency to enantiomerize in water of two ketones (1 and 2) endowed with inhibitory activity against monoamine oxidases (MAOs) and the results were confirmed by experimental kinetics measurements performed in organic medium. As a demonstration of practical potentialities of the approach, four new structures, conceived as simple chemical modifications of 1 and 2, were designed to improve/reduce the stereostability grade of the starting anti-MAO ketones. The possibility to extend easily the procedure to other classes of C-H acids appears of interest.

Time Evolution of Activity Concentration of Natural Emitters in a Scenario Affected By Previous Phosphogypsum Contamination

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

Villa, M.; Hurtado, S.; Mantero, J.

2008-08-07

The estuary formed by the confluence of Tinto and Odiel river-mouths is located in the South of Spain, close to Huelva town. This estuary has been deeply studied through the years because it has a double particularity. On one hand, since the beginning of the 1960s, the estuary has been affected by direct and indirect phosphogypsum (pg.) releases from two phosphoric acid and fertilizers factories that are working in the area. On the other hand, the pyrite mining operations upstream the Odiel and Tinto rivers has caused historically the formation of H{sub 2}SO{sub 4}, through oxidation of the natural sulphurmore » deposits, the acidification of the waters and the consequent mobilisation of heavy metals from the mining area to the Huelva estuary. As a consequence, enhancement contamination levels in natural emitters from the {sup 238}U series were found in the surroundings of the factories in the previous years to 1998. However, in 1998 the management policy of waste releases drastically changed in the area, and direct discharges to Tinto and Odiel River had to be ceased.A thorough study of the affected zone is being carried out. Riverbed sediments and water samples have been analyzed from four different sampling campaigns in the estuary during the years 1999, 2001, 2002 and 2005. Different radioanalytical techniques have been employed to obtain the activity concentrations of U-isotopes, Th-isotopes, {sup 226}Ra, {sup 210}Pb and {sup 210}Po. Furthermore, the results for the rates of de-contamination of the area are presented. This data will be discussed in order to establish the present status of the contamination in the area, and moreover, to predict the time-evolution of the self-cleaning.« less

Negative feedback regulation of human platelets via autocrine activation of the platelet-derived growth factor alpha-receptor.

PubMed

Vassbotn, F S; Havnen, O K; Heldin, C H; Holmsen, H

1994-05-13

Human platelets contain platelet-derived growth factor (PDGF) in their alpha-granules which is released during platelet exocytosis. We show by immunoprecipitation and 125I-PDGF binding experiments that human platelets have functionally active PDGF alpha-receptors, but not beta-receptors. The PDGF alpha-receptor (PDGFR-alpha) was identified as a 170-kDa glycosylated protein-tyrosine kinase as found in other cell types. Stimulation of platelets with 0.1 unit/ml thrombin resulted in a significant increase (2-5-fold) of the tyrosine phosphorylation of the PDGFR-alpha, as determined by immunoprecipitation with phosphotyrosine antiserum as well as with PDGFR-alpha antiserum. The observed thrombin-induced autophosphorylation of the PDGFR-alpha was inhibited by the addition of a neutralizing monoclonal PDGF antibody. Thus, our results suggest that the platelet PDGFR-alpha is stimulated in an autocrine manner by PDGF secreted during platelet activation. Preincubation of platelets with PDGF inhibited thrombin-induced platelet aggregation and secretion of ATP + ADP and beta-hexosaminidase. Thrombin-induced platelet aggregation was also reversed when PDGF was added 30 s after thrombin stimulation. Inhibition of the autocrine PDGF pathway during platelet activation by the PDGF antibody led to a potentiation of thrombin-induced beta-hexosaminidase secretion. Thus, the PDGFR-alpha takes part in a negative feedback regulation during platelet activation. Our demonstration of PDGF alpha-receptors on human platelets and its inhibitory function during platelet activation identifies a new possible role of PDGF in the regulation of thrombosis.

The Effects of Exercise on Brain Inflammation

DTIC Science & Technology

2010-06-01

macrophages and lymphocytes release pro -inflammatory cytokines such as interleukin-1β and tumor necrosis factor alpha that induce the subsequent...inflammatory cascade. These pro -inflammatory cytokines are responsible for weakening the BBB so that effector cells from the periphery can enter the CNS...restrictions on Cover and Notice Page: Distribution A – Approved for Public Release DISCUSSION IL-1β Interleukin-1β (IL-1β) is a pro -inflammatory cytokine

Workshop on Biophysics of Transmembrane Electric Fields

DTIC Science & Technology

1990-11-15

binding of K (a- ketoglutarate ) to the high energy ER form releases only a part of the energy induced in the system. This partial release accomplishes two...nature (eg. calcium , polyethylene glycol), a specialized protein (eg. influenza HA spike glycoprotein), a natural protein or peptide used under...that alamethicin has a stable alpha -helical conformation of about ten residues long beginning at the N terminus and at least in some solvent systems

Polyisoprene matrix for progesterone release: in vitro and in vivo studies.

PubMed

Heredia, V; Bianco, I D; Tríbulo, H; Tríbulo, R; Seoane, M Ferro; Faudone, S; Cuffini, S L; Demichelis, N A; Schalliol, H; Beltramo, D M

2009-12-01

Latex, a polyisoprene (PI) hydrophobic elastomer, was evaluated in vitro and in vivo as a matrix for intravaginal steroid hormone delivery. Matrices containing hormone were prepared by swelling latex in chloroform that contained soluble progesterone (P4). In vitro studies demonstrate that P4 release from PI follows a zero order model during at least 100 h and depends on initial load up to 10 mg cm(-2). The release of P4 from a PI matrix was found to be two times faster than from a polydimethylsiloxane (PDMS) matrix. FT-IR and X-ray powder diffraction analysis of P4 polymorphs show that when nucleated in PDMS, the hormone crystallizes only in alpha-form while in latex, crystallizes as a mixture of alpha- and beta-form. In vivo studies show that devices with a PI matrix containing 0.5 g of P4 are effective to reach plasma levels above 1 ng ml(-1) that are needed to synchronize estrous in cattle. Altogether, the results show that PI, a vulcanized polymer with a carbon-carbon backbone, can be used as a new matrix for the intravaginal administration of progesterone with improved release profile than silicone and that the matrix can influence the crystalline state of the hormone.

Ion Motion Induced Emittance Growth of Matched Electron Beams in Plasma Wakefields

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

An, Weiming; Lu, Wei; Huang, Chengkun

2017-06-14

Plasma-based acceleration is being considered as the basis for building a future linear collider. Nonlinear plasma wakefields have ideal properties for accelerating and focusing electron beams. Preservation of the emittance of nano-Coulomb beams with nanometer scale matched spot sizes in these wakefields remains a critical issue due to ion motion caused by their large space charge forces. We use fully resolved quasistatic particle-in-cell simulations of electron beams in hydrogen and lithium plasmas, including when the accelerated beam has different emittances in the two transverse planes. The projected emittance initially grows and rapidly saturates with a maximum emittance growth of lessmore » than 80% in hydrogen and 20% in lithium. The use of overfocused beams is found to dramatically reduce the emittance growth. In conclusion, the underlying physics that leads to the lower than expected emittance growth is elucidated.« less

Emission Testing Results of Thermally Stable, Metamaterial, Selective-Emitters for Thermophotovoltaics

NASA Astrophysics Data System (ADS)

Levinson, Katherine; Naka, Norihito; Pfiester, Nicole; Licht, Abigail; Vandervelde, Tom

2015-03-01

In thermophotovoltaics, the energy from a heated emitter is converted to electricity by a photovoltaic diode. A selective emitter can be used to emit a narrow band of wavelengths tailored to the bandgap of the photovoltaic diode. This spectral shaping improves the conversion efficiency of the diode and reduces undesirable diode heating. In our research, we study selective emitters based on metamaterials composed of repeating nanoscale structures. The emission characteristics of these materials vary based on the compositional structure, allowing the emitted spectrum to be tunable. Simulations were performed with CST Microwave Studio to design emitters with peak wavelengths ranging from 1-10 microns. The structures were then fabricated using physical vapor deposition and electron beam lithography on a sapphire substrate. Emitter materials studied include gold, platinum, and iridium. Here we report on the emission spectra of the selective emitters and the post-heating structural integrity.

Doping-free white organic light-emitting diodes without blue molecular emitter: An unexplored approach to achieve high performance via exciplex emission

NASA Astrophysics Data System (ADS)

Luo, Dongxiang; Xiao, Ye; Hao, Mingming; Zhao, Yu; Yang, Yibin; Gao, Yuan; Liu, Baiquan

2017-02-01

Doping-free white organic light-emitting diodes (DF-WOLEDs) are promising for the low-cost commercialization because of their simplified device structures. However, DF-WOLEDs reported thus far in the literature are based on the use of blue single molecular emitters, whose processing can represent a crucial point in device manufacture. Herein, DF-WOLEDs without the blue single molecular emitter have been demonstrated by managing a blue exciplex system. For the single-molecular-emitter (orange or yellow emitter) DF-WOLEDs, (i) a color rendering index (CRI) of 81 at 1000 cd/m2 can be obtained, which is one of the highest for the single-molecular-emitter WOLEDs, or (ii) a high efficiency of 35.4 lm/W can be yielded. For the dual-molecular-emitter (yellow/red emitters) DF-WOLED, a high CRI of 85 and low correlated color temperature of 2376 K at 1000 cd/m2 have been simultaneously achieved, which has not been reported by previous DF-WOLEDs. Such presented findings may unlock an alternative avenue to the simplified but high-performance WOLEDs.

Single photon emission from plasma treated 2D hexagonal boron nitride.

PubMed

Xu, Zai-Quan; Elbadawi, Christopher; Tran, Toan Trong; Kianinia, Mehran; Li, Xiuling; Liu, Daobin; Hoffman, Timothy B; Nguyen, Minh; Kim, Sejeong; Edgar, James H; Wu, Xiaojun; Song, Li; Ali, Sajid; Ford, Mike; Toth, Milos; Aharonovich, Igor

2018-05-03

Artificial atomic systems in solids are becoming increasingly important building blocks in quantum information processing and scalable quantum nanophotonic networks. Amongst numerous candidates, 2D hexagonal boron nitride has recently emerged as a promising platform hosting single photon emitters. Here, we report a number of robust plasma and thermal annealing methods for fabrication of emitters in tape-exfoliated hexagonal boron nitride (hBN) crystals. A two-step process comprising Ar plasma etching and subsequent annealing in Ar is highly robust, and yields an eight-fold increase in the concentration of emitters in hBN. The initial plasma-etching step generates emitters that suffer from blinking and bleaching, whereas the two-step process yields emitters that are photostable at room temperature with emission wavelengths greater than ∼700 nm. Density functional theory modeling suggests that the emitters might be associated with defect complexes that contain oxygen. This is further confirmed by generating the emitters via annealing hBN in air. Our findings advance the present understanding of the structure of quantum emitters in hBN and enhance the nanofabrication toolkit needed to realize integrated quantum nanophotonic circuits.

High-speed and on-chip graphene blackbody emitters for optical communications by remote heat transfer.

PubMed

Miyoshi, Yusuke; Fukazawa, Yusuke; Amasaka, Yuya; Reckmann, Robin; Yokoi, Tomoya; Ishida, Kazuki; Kawahara, Kenji; Ago, Hiroki; Maki, Hideyuki

2018-03-29

High-speed light emitters integrated on silicon chips can enable novel architectures for silicon-based optoelectronics, such as on-chip optical interconnects, and silicon photonics. However, conventional light sources based on compound semiconductors face major challenges for their integration with a silicon-based platform because of their difficulty of direct growth on a silicon substrate. Here we report ultra-high-speed (100-ps response time), highly integrated graphene-based on-silicon-chip blackbody emitters in the near-infrared region including telecommunication wavelength. Their emission responses are strongly affected by the graphene contact with the substrate depending on the number of graphene layers. The ultra-high-speed emission can be understood by remote quantum thermal transport via surface polar phonons of the substrates. We demonstrated real-time optical communications, integrated two-dimensional array emitters, capped emitters operable in air, and the direct coupling of optical fibers to the emitters. These emitters can open new routes to on-Si-chip, small footprint, and high-speed emitters for highly integrated optoelectronics and silicon photonics.

Specific lysine labeling by 18OH- during alkaline cleavage of the alpha-1-antitrypsin-trypsin complex.

PubMed Central

Cohen, A B; Gruenke, L D; Craig, J C; Geczy, D

1977-01-01

alpha-1-Antitrypsin is a serum protein that inhibits many proteolytic enzymes. Recently, it was suggested that the alpha-1-antitrypsin-trypsin complex is an acyl ester analogous to the acyl intermediate that forms between trypsin and its substrates. In previous work we showed that the alpha-1-antitrypsin-trypsin complex can be split at high pH, releasing a component of alpha-1-antitrypsin. This component had a new carboxyl-terminal lysine, and it had lost a peptide of about 4000 daltons. In order to determine whether the alpha-1-antitrypsin is bound to trypsin through the new carboxy-terminal lysine, as would be expected if the above hypothesis is correct, we split the complex in the presence of 18OH-. When the new carboxy-terminal lysine was cleaved with carboxypeptidase B, singly labeled, doubly labeled, and unlabeled lysine were recovered. These data support the hypothesis that the alpha-1-antitrypsin-trypsin complex is an acyl ester or a tetrahedral precursor that is transformed into the acyl ester form at high pH. If other enzymes are bound by a similar mechanism, the methods used may be useful in determining which amino acids on alpha-1-antitrypsin bind covalently to each enzyme. PMID:303770

A Pauson-Khand-type reaction between alkynes and olefinic aldehydes catalyzed by rhodium/cobalt heterobimetallic nanoparticles: an olefinic aldehyde as an olefin and CO source.

PubMed

Park, Kang Hyun; Jung, Il Gu; Chung, Young Keun

2004-04-01

Co/Rh (Co:Rh = 2:2) heterobimetallic nanoparticles derived from Co(2)Rh(2)(CO)(12) react with alkynes and alpha,beta-unsaturated aldehydes such as acrolein, crotonaldehyde, and cinnamic aldehyde and release products resulting from [2 + 2 + 1]cycloaddition of alkyne, carbon monoxide, and alkene. alpha,beta-Unsaturated aldehydes act as a CO and alkene source. These reactions produce 2-substituted cyclopentenones.

Interleukin-6 production by human monocytes stimulated with Cryptococcus neoformans components.

PubMed Central

Delfino, D; Cianci, L; Lupis, E; Celeste, A; Petrelli, M L; Curró, F; Cusumano, V; Teti, G

1997-01-01

In order to ascertain if Cryptococcus neoformans components can induce interleukin-6 (IL-6) production, we stimulated human whole blood with purified capsular products. Their potencies in stimulating IL-6 release were mannoproteins > galactoxylomannan = glucuronoxylomannan > alpha(1-3)glucan. IL-6 production was tumor necrosis factor alpha independent and required the presence of monocytes and plasma. Since IL-6 can stimulate replication of the human immunodeficiency virus in monocytic cells, these findings may be clinically relevant. PMID:9169790

Disruption of Brewers' yeast by hydrodynamic cavitation: Process variables and their influence on selective release.

PubMed

Balasundaram, B; Harrison, S T L

2006-06-05

Intracellular products, not secreted from the microbial cell, are released by breaking the cell envelope consisting of cytoplasmic membrane and an outer cell wall. Hydrodynamic cavitation has been reported to cause microbial cell disruption. By manipulating the operating variables involved, a wide range of intensity of cavitation can be achieved resulting in a varying extent of disruption. The effect of the process variables including cavitation number, initial cell concentration of the suspension and the number of passes across the cavitation zone on the release of enzymes from various locations of the Brewers' yeast was studied. The release profile of the enzymes studied include alpha-glucosidase (periplasmic), invertase (cell wall bound), alcohol dehydrogenase (ADH; cytoplasmic) and glucose-6-phosphate dehydrogenase (G6PDH; cytoplasmic). An optimum cavitation number Cv of 0.13 for maximum disruption was observed across the range Cv 0.09-0.99. The optimum cell concentration was found to be 0.5% (w/v, wet wt) when varying over the range 0.1%-5%. The sustained effect of cavitation on the yeast cell wall when re-circulating the suspension across the cavitation zone was found to release the cell wall bound enzyme invertase (86%) to a greater extent than the enzymes from other locations of the cell (e.g. periplasmic alpha-glucosidase at 17%). Localised damage to the cell wall could be observed using transmission electron microscopy (TEM) of cells subjected to less intense cavitation conditions. Absence of the release of cytoplasmic enzymes to a significant extent, absence of micronisation as observed by TEM and presence of a lower number of proteins bands in the culture supernatant on SDS-PAGE analysis following hydrodynamic cavitation compared to disruption by high-pressure homogenisation confirmed the selective release offered by hydrodynamic cavitation. Copyright 2006 Wiley Periodicals, Inc.

Effect of Escherichia coli and Lactobacillus rhamnosus on Macrophage Inflammatory Protein 3α, Tumor Necrosis Factor Alpha, and Transforming Growth Factor β Release by Polarized Rat Uterine Epithelial Cells in Culture

PubMed Central

Crane-Godreau, Mardi A.; Wira, Charles R.

2004-01-01

Entry of bacteria from the vagina into the uterus raises the question of uterine epithelial cell (UEC) signaling in response to the presence of bacteria. Our model system helps to define microbially elicited UEC basolateral cytokine release, important in regulating underlying stromal immune cell protection. UECs from adult rats were grown in cell culture inserts to establish a confluent polarized monolayer as was determined by transepithelial resistance (TER). Polarized epithelial cell cultures were treated apically with live or heat-killed Escherichia coli or Lactobacillus rhamnosus prior to collection of basolateral media after 24 h of incubation. Coculture of polarized UECs with live E. coli had no effect on epithelial cell TER. In response to exposure to live E. coli, epithelial cell basolateral release of macrophage inflammatory protein 3α (MIP3α) and tumor necrosis factor alpha (TNF-α) increased at a time when basolateral release of biologically active transforming growth factor β (TGF-β) decreased. Incubation of UECs with heat-killed E. coli resulted in an increased basolateral release of MIP3α and TNF-α, without affecting TER or TGF-β. In contrast to E. coli, live or heat-killed L. rhamnosus had no effect on TER or cytokine release. These studies indicate that polarized rat UECs respond to gram-negative E. coli by releasing the cytokines MIP3α and TNF-α, signals important to both the innate and adaptive immune systems. These findings suggest that UEC responses to bacteria are selective and important in initiating and regulating immune protection in the female reproductive tract. PMID:15039305

Thermal emittance enhancement of graphite-copper composites for high temperature space based radiators

NASA Technical Reports Server (NTRS)

Rutledge, Sharon K.; Forkapa, Mark J.; Cooper, Jill M.

1991-01-01

Graphite-copper composites are candidate materials for space based radiators. The thermal emittance of this material, however, is a factor of two lower than the desired emittance for these systems of greater than or equal to 0.85. Arc texturing was investigated as a surface modification technique for enhancing the emittance of the composite. Since the outer surface of the composite is copper, and samples of the composite could not be readily obtained for testing, copper was used for optimization testing. Samples were exposed to various frequencies and currents of arcs during texturing. Emittances near the desired goal were achieved at frequencies less than 500 Hz. Arc current did not appear to play a major role under 15 amps. Particulate carbon was observed on the surface, and was easily removed by vibration and handling. In order to determine morphology adherence, ultrasonic cleaning was used to remove the loosely adherent material. This reduced the emittance significantly. Emittance was found to increase with increasing frequency for the cleaned samples up to 500 Hz. The highest emittance achieved on these samples over the temperature range of interest was 0.5 to 0.6, which is approximately a factor of 25 increase over the untextured copper emittance.

Chemically doped three-dimensional porous graphene monoliths for high-performance flexible field emitters.

PubMed

Kim, Ho Young; Jeong, Sooyeon; Jeong, Seung Yol; Baeg, Kang-Jun; Han, Joong Tark; Jeong, Mun Seok; Lee, Geon-Woong; Jeong, Hee Jin

2015-03-12

Despite the recent progress in the fabrication of field emitters based on graphene nanosheets, their morphological and electrical properties, which affect their degree of field enhancement as well as the electron tunnelling barrier height, should be controlled to allow for better field-emission properties. Here we report a method that allows the synthesis of graphene-based emitters with a high field-enhancement factor and a low work function. The method involves forming monolithic three-dimensional (3D) graphene structures by freeze-drying of a highly concentrated graphene paste and subsequent work-function engineering by chemical doping. Graphene structures with vertically aligned edges were successfully fabricated by the freeze-drying process. Furthermore, their number density could be controlled by varying the composition of the graphene paste. Al- and Au-doped 3D graphene emitters were fabricated by introducing the corresponding dopant solutions into the graphene sheets. The resulting field-emission characteristics of the resulting emitters are discussed. The synthesized 3D graphene emitters were highly flexible, maintaining their field-emission properties even when bent at large angles. This is attributed to the high crystallinity and emitter density and good chemical stability of the 3D graphene emitters, as well as to the strong interactions between the 3D graphene emitters and the substrate.

Construction and measurements of a vacuum-swing-adsorption radon-mitigation system

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

Schnee, R. W.; Bunker, R.; Ghulam, G.

Long-lived alpha and beta emitters in the {sup 222}Rn decay chain on (and near) detector surfaces may be the limiting background in many experiments attempting to detect dark matter or neutrinoless double beta decay, and in screening detectors. In order to reduce backgrounds from radon-daughter plate-out onto the wires of the Beta Cage during its assembly, an ultra-low-radon cleanroom is being commissioned at Syracuse University using a vacuum-swing-adsorption radon-mitigation system. The radon filter shows ∼20× reduction at its output, from 7.47±0.56 to 0.37±0.12 Bq/m{sup 3}, and the cleanroom radon activity meets project requirements, with a lowest achieved value consistent withmore » that of the filter, and levels consistently < 2 Bq/m{sup 3}.« less

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

Adelstein, S.J.; Kassis, A.I.

This report describes many factors that need to be considered if radioimmunotherapy is to become a commonplace reality. For beta-emitting radionuclides, two physical features of importance are half-life and energy, with the latter determining the range. These features must be matched to the pharmacokinetics of the carrier and the distribution of the radionuclide, both macroscopically and microscopically. Alpha-particle emitters could be considered for cells that are readily accessible to the labeled antibody and for populations that uniformly and constantly display the targeted antigen or idiotype, e.g., trafficking cells such as T or B lymphocytes. For cells that concentrate the radioactivemore » label, the use of low-energy electrons should be examined. If the radionuclide is translocated to the nucleus, the Auger effect can be particularly lethal because of the high LET-like biological response. 15 refs., 3 figs., 2 tabs.« less

Determination of Low Level Alpha and Beta Emitters Using Liquid-Liquid Extraction and a Liquid Scintillation Spectrometer

NASA Astrophysics Data System (ADS)

Yu, Yu-Fu; BjØRnstad, H. E.; Salbu, B.

Two radiochemical procedures for determination of low level strontium-90 and plutonium-239+240 in environmental and biological materials using combined selective solvent extraction with low level liquid scintillation counting have been presented. Y-90, the daughter nuclide of Sr-90, and Pu-239+240 are selectively extracted from nitric acid solution into 5% di(-2ethylhexyl)phosphoric acid (HDEHP) in toluene and the radionuclides of interest in organic phase are counted with an ultra low level scintillation counter "Quantulus". The lower detection limits for Sr-90 and Pu-239+240 are estimated to be 20 mBq and 0.3 mBq respectively. The developed procedures have been tested for soma environmental and biological samples and the preminarly results show that they are more simple and time-saving than traditional methods.

Do Lyman-alpha photons escape from star-forming galaxies through dust-holes?

NASA Astrophysics Data System (ADS)

Wofford, Aida

2012-10-01

The hydrogen Lyman-alpha line is arguably the most important signature of galaxies undergoing their first violent burst of star formation. Although Lya photons are easily destroyed by dust, candidate Lya emitters have been detected at z>5. Thus the line can potentially be used to probe galaxy formation and evolution, as long as the astrophysical processes that regulate the escape of Lya photons from star-forming galaxies are well understood.We request 15 orbits for imaging in Lya and the FUV continuum with ACS/SBC, and in the H-beta/H-alpha ratio {proxy for dust extinction} with WFC3/UVIS, a sample of isolated non-AGN face-on spirals for which our team previously obtained and analyzed COS FUV spectroscopy of the central regions. Each target shows a different Lya profile, i.e., pure absorption, P-Cygni like, and multiple-emission. From the COS data, we already know the starburst phase and H I gas velocity. The images would greatly increase the impact of our spectroscopic study by enabling us to 1} conclusively determine if Lya photons escape through dust-holes, 2} assess the relative importance of dust extinction, ISM kinematics, and starburst phase in regulating the Lya escape, 3} clarify what we can really learn from the Lya equivalent width, and 4} provide constraints on the dust extinction to Lya 3D radiative transfer models. Ultimately this program will inform our understanding of the Lya escape at high redshift by providing spatially resolved views of the local conditions within star-forming galaxies that favor escape.

Superresolution microscope image reconstruction by spatiotemporal object decomposition and association: application in resolving t-tubule structure in skeletal muscle

PubMed Central

Sun, Mingzhai; Huang, Jiaqing; Bunyak, Filiz; Gumpper, Kristyn; De, Gejing; Sermersheim, Matthew; Liu, George; Lin, Pei-Hui; Palaniappan, Kannappan; Ma, Jianjie

2014-01-01

One key factor that limits resolution of single-molecule superresolution microscopy relates to the localization accuracy of the activated emitters, which is usually deteriorated by two factors. One originates from the background noise due to out-of-focus signals, sample auto-fluorescence, and camera acquisition noise; and the other is due to the low photon count of emitters at a single frame. With fast acquisition rate, the activated emitters can last multiple frames before they transiently switch off or permanently bleach. Effectively incorporating the temporal information of these emitters is critical to improve the spatial resolution. However, majority of the existing reconstruction algorithms locate the emitters frame by frame, discarding or underusing the temporal information. Here we present a new image reconstruction algorithm based on tracklets, short trajectories of the same objects. We improve the localization accuracy by associating the same emitters from multiple frames to form tracklets and by aggregating signals to enhance the signal to noise ratio. We also introduce a weighted mean-shift algorithm (WMS) to automatically detect the number of modes (emitters) in overlapping regions of tracklets so that not only well-separated single emitters but also individual emitters within multi-emitter groups can be identified and tracked. In combination with a maximum likelihood estimator method (MLE), we are able to resolve low to medium density of overlapping emitters with improved localization accuracy. We evaluate the performance of our method with both synthetic and experimental data, and show that the tracklet-based reconstruction is superior in localization accuracy, particularly for weak signals embedded in a strong background. Using this method, for the first time, we resolve the transverse tubule structure of the mammalian skeletal muscle. PMID:24921337

Theory and measurements of emittance preservation in plasma wakefield acceleration

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

Frederico, Joel

2016-12-01

In this dissertation, we examine the preservation and measurement of emittance in the plasma wakefield acceleration blowout regime. Plasma wakefield acceleration (PWFA) is a revolutionary approach to accelerating charged particles that has been demonstrated to have the potential for gradients orders of magnitude greater than traditional approaches. The application of PWFA to the design of a linear collider will make new high energy physics research possible, but the design parameters must first be shown to be competitive with traditional methods. Emittance preservation is necessary in the design of a linear collider in order to maximize luminosity. We examine the conditionsmore » necessary for circular symmetry in the PWFA blowout regime, and demonstrate that current proposals meet these bounds. We also present an application of beam lamentation which describes the process of beam parameter and emittance matching. We show that the emittance growth saturates as a consequence of energy spread in the beam. The initial beam parameters determine the amount of emittance growth, while the contribution of energy spread is negligible. We also present a model for ion motion in the presence of a beam that is much more dense than the plasma. By combining the model of ion motion and emittance growth, we find the emittance growth due to ion motion is minimal in the case of marginal ion motion. In addition, we present a simulation that validates the ion motion model, which is under further development to examine emittance growth of both marginal and pronounced ion motion. Finally, we present a proof-of-concept of an emittance measurement which may enable the analysis of emittance preservation in future PWFA experiments.« less

Superresolution microscope image reconstruction by spatiotemporal object decomposition and association: application in resolving t-tubule structure in skeletal muscle.

PubMed

Sun, Mingzhai; Huang, Jiaqing; Bunyak, Filiz; Gumpper, Kristyn; De, Gejing; Sermersheim, Matthew; Liu, George; Lin, Pei-Hui; Palaniappan, Kannappan; Ma, Jianjie

2014-05-19

One key factor that limits resolution of single-molecule superresolution microscopy relates to the localization accuracy of the activated emitters, which is usually deteriorated by two factors. One originates from the background noise due to out-of-focus signals, sample auto-fluorescence, and camera acquisition noise; and the other is due to the low photon count of emitters at a single frame. With fast acquisition rate, the activated emitters can last multiple frames before they transiently switch off or permanently bleach. Effectively incorporating the temporal information of these emitters is critical to improve the spatial resolution. However, majority of the existing reconstruction algorithms locate the emitters frame by frame, discarding or underusing the temporal information. Here we present a new image reconstruction algorithm based on tracklets, short trajectories of the same objects. We improve the localization accuracy by associating the same emitters from multiple frames to form tracklets and by aggregating signals to enhance the signal to noise ratio. We also introduce a weighted mean-shift algorithm (WMS) to automatically detect the number of modes (emitters) in overlapping regions of tracklets so that not only well-separated single emitters but also individual emitters within multi-emitter groups can be identified and tracked. In combination with a maximum likelihood estimator method (MLE), we are able to resolve low to medium density of overlapping emitters with improved localization accuracy. We evaluate the performance of our method with both synthetic and experimental data, and show that the tracklet-based reconstruction is superior in localization accuracy, particularly for weak signals embedded in a strong background. Using this method, for the first time, we resolve the transverse tubule structure of the mammalian skeletal muscle.

Long-lived and highly efficient green and blue phosphorescent emitters and device architectures for OLED displays

NASA Astrophysics Data System (ADS)

Eickhoff, Christian; Murer, Peter; Geßner, Thomas; Birnstock, Jan; Kröger, Michael; Choi, Zungsun; Watanabe, Soichi; May, Falk; Lennartz, Christian; Stengel, Ilona; Münster, Ingo; Kahle, Klaus; Wagenblast, Gerhard; Mangold, Hannah

2015-09-01

In this paper, two OLED device concepts are introduced. First, classical phosphorescent green carbene emitters with unsurpassed lifetime, combined with low voltage and high efficiency are presented and the associated optimized OLED stacks are explained. Second, a path towards highly efficient, long-lived deep blue systems is shown. The high efficiencies can be reached by having the charge-recombination on the phosphorescent carbene emitter while at the same time short emissive lifetimes are realized by fast energy transfer to the fluorescent emitter, which eventually allows for higher OLED stability in the deep blue. Device architectures, materials and performance data are presented showing that carbene type emitters have the potential to outperform established phosphorescent green emitters both in terms of lifetime and efficiency. The specific class of green emitters under investigation shows distinctly larger electron affinities (2.1 to 2.5 eV) and ionization potentials (5.6 to 5.8 eV) as compared to the "standard" emitter Ir(ppy)3 (5.0/1.6 eV). This difference in energy levels requires an adopted OLED design, in particular with respect to emitter hosts and blocking layers. Consequently, in the diode setup presented here, the emitter species is electron transporting or electron trapping. For said green carbene emitters, the typical peak wavelength is 525 nm yielding CIE color coordinates of (x = 0.33, y = 0.62). Device data of green OLEDs are shown with EQEs of 26 %. Driving voltage at 1000 cd/m2 is below 3 V. In an optimized stack, a device lifetime of LT95 > 15,000 h (1000 cd/m2) has been reached, thus fulfilling AMOLED display requirements.

Mechanisms of postspaceflight orthostatic hypotension: low alpha1-adrenergic receptor responses before flight and central autonomic dysregulation postflight

NASA Technical Reports Server (NTRS)

Meck, Janice V.; Waters, Wendy W.; Ziegler, Michael G.; deBlock, Heidi F.; Mills, Paul J.; Robertson, David; Huang, Paul L.

2004-01-01

Although all astronauts experience symptoms of orthostatic intolerance after short-duration spaceflight, only approximately 20% actually experience presyncope during upright posture on landing day. The presyncopal group is characterized by low vascular resistance before and after flight and low norepinephrine release during orthostatic stress on landing day. Our purpose was to determine the mechanisms of the differences between presyncopal and nonpresyncopal groups. We studied 23 astronauts 10 days before launch, on landing day, and 3 days after landing. We measured pressor responses to phenylephrine injections; norepinephrine release with tyramine injections; plasma volumes; resting plasma levels of chromogranin A (a marker of sympathetic nerve terminal release), endothelin, dihydroxyphenylglycol (DHPG, an intracellular metabolite of norepinephrine); and lymphocyte beta(2)-adrenergic receptors. We then measured hemodynamic and neurohumoral responses to upright tilt. Astronauts were separated into two groups according to their ability to complete 10 min of upright tilt on landing day. Compared with astronauts who were not presyncopal on landing day, presyncopal astronauts had 1). significantly smaller pressor responses to phenylephrine both before and after flight; 2). significantly smaller baseline norepinephrine, but significantly greater DHPG levels, on landing day; 3). significantly greater norepinephrine release with tyramine on landing day; and 4). significantly smaller norepinephrine release, but significantly greater epinephrine and arginine vasopressin release, with upright tilt on landing day. These data suggest that the etiology of orthostatic hypotension and presyncope after spaceflight includes low alpha(1)-adrenergic receptor responsiveness before flight and a remodeling of the central nervous system during spaceflight such that sympathetic responses to baroreceptor input become impaired.

Mechanisms of postspaceflight orthostatic hypotension: low alpha1-adrenergic receptor responses before flight and central autonomic dysregulation postflight.

PubMed

Meck, Janice V; Waters, Wendy W; Ziegler, Michael G; deBlock, Heidi F; Mills, Paul J; Robertson, David; Huang, Paul L

2004-04-01

Although all astronauts experience symptoms of orthostatic intolerance after short-duration spaceflight, only approximately 20% actually experience presyncope during upright posture on landing day. The presyncopal group is characterized by low vascular resistance before and after flight and low norepinephrine release during orthostatic stress on landing day. Our purpose was to determine the mechanisms of the differences between presyncopal and nonpresyncopal groups. We studied 23 astronauts 10 days before launch, on landing day, and 3 days after landing. We measured pressor responses to phenylephrine injections; norepinephrine release with tyramine injections; plasma volumes; resting plasma levels of chromogranin A (a marker of sympathetic nerve terminal release), endothelin, dihydroxyphenylglycol (DHPG, an intracellular metabolite of norepinephrine); and lymphocyte beta(2)-adrenergic receptors. We then measured hemodynamic and neurohumoral responses to upright tilt. Astronauts were separated into two groups according to their ability to complete 10 min of upright tilt on landing day. Compared with astronauts who were not presyncopal on landing day, presyncopal astronauts had 1). significantly smaller pressor responses to phenylephrine both before and after flight; 2). significantly smaller baseline norepinephrine, but significantly greater DHPG levels, on landing day; 3). significantly greater norepinephrine release with tyramine on landing day; and 4). significantly smaller norepinephrine release, but significantly greater epinephrine and arginine vasopressin release, with upright tilt on landing day. These data suggest that the etiology of orthostatic hypotension and presyncope after spaceflight includes low alpha(1)-adrenergic receptor responsiveness before flight and a remodeling of the central nervous system during spaceflight such that sympathetic responses to baroreceptor input become impaired.

Lyman-α emitters gone missing: the different evolution of the bright and faint populations

NASA Astrophysics Data System (ADS)

Weinberger, Lewis H.; Kulkarni, Girish; Haehnelt, Martin G.; Choudhury, Tirthankar Roy

2018-06-01

We model the transmission of the Lyman-α line through the circum- and intergalactic media around dark matter haloes expected to host Lyman-alpha emitters (LAEs) at z ≥ 5.7, using the high-dynamic-range Sherwood simulations. We find very different CGM environments around more massive haloes (˜1011M⊙) compared to less massive haloes (˜109M⊙) at these redshifts, which can contribute to a different evolution of the Lyα transmission from LAEs within these haloes. Additionally we confirm that part of the differential evolution could result from bright LAEs being more likely to reside in larger ionized regions. We conclude that a combination of the CGM environment and the IGM ionization structure is likely to be responsible for the differential evolution of the bright and faint ends of the LAE luminosity function at z ≥ 6. More generally, we confirm the suggestion that the self-shielded neutral gas in the outskirts of the host halo can strongly attenuate the Lyα emission from high redshift galaxies. We find that this has a stronger effect on the more massive haloes hosting brighter LAEs. The faint-end of the LAE luminosity function is thus a more reliable probe of the average ionization state of the IGM. Comparing our model for LAEs with a range of observational data we find that the favoured reionization histories are our previously advocated `Late' and `Very Late' reionization histories, in which reionization finishes rather rapidly at around z ≃ 6.

Chromate conversion coating: Iridite 14-2 thermal/optical characterization

NASA Astrophysics Data System (ADS)

Rodriguez, Marcello

2012-10-01

Chromate Conversion Coating (CCC) BOL and EOL thermal properties (absorptance and emittance) have been unspecified throughout the industry and throughout its use here at GSFC. Being key values essential for thermal engineers to assess thermal space conditions, this study focuses on the current application process, its outputted properties and assess whether these properties can in turn be classified under proper documentation. The results show that wide variations in the process overcome any possibility in thermally classifying this coating. A new set of samples were fabricated (in preparation for space environmental studies) in which a more controlled approach to applying the CCC was made. The resulting thermal values continued to show variations indicating lack of bath agitation existing within the bath. From this study you can conclude that witness samples may not best represent the flight hardware for this coating. The study then turns to space environmental study testing samples to high temperature (80°C), high vacuum, and combination of both, and UV radiation totaling 1625 ESH. The results showed an extremely dynamic coating sensitive to every environmental condition it was exposed to. Though the initial changes to the coating are drastic, post initial changes appear to be minuscule making EOL predictions more attainable. These results show that the worst case alpha/emittance values are likely after ground processing and before space exposure. From the data obtained in this study greater understanding and more informed decisions can be made with respect to this coating.

Vitamin C attenuation of the development of type I diabetes mellitus by interferon-alpha.

PubMed

al-Zuhair, H; Mohamed, H E

1998-07-01

Interferon alpha (IFN-alpha) inhibits insulin release and may be cytotoxic to pancreatic islets. Increased free radical activity may be implicated in the cytotoxic action of IFN-alpha and development of diabetes mellitus. Therefore we measured markers of free radical activity (lipid peroxides and the non-peroxide-conjugated diene isomer of linoleic acid [PL-9,11-LA']) along with some pancreatic variables in male albino rats treated with IFN-alpha, as well as the possible protective effect of two antioxidants, vitamin C and mannitol. Compared to untreated rats, it was shown that IFN-alpha induced an increase in plasma glucose. Pancreatic and serum insulin, as well as serum C-peptide, were increased after 1 week, then their levels were reduced after 2 weeks. Plasma lipids peroxides and (PL-9,11-LA') were markedly elevated, while linoleic acid was reduced. These changes in the studied parameters were attributed, in part, to the superoxide and free radical generation during IFN-alpha treatment. Plasma glucagon was increased after 2 weeks. Administration of vitamin C along with IFN-alpha succeeded in modulating most of the altered parameters affected during IFN-alpha. The hyperglycaemic effect of IFN-alpha was greatly ameliorated and the negative effect on pancreatic and serum insulin and serum C-peptide were nearly abolished. The elevated levels of lipid peroxide and (PL-9,11-LA') and the reduction in linoleic acid being normalised. The only persistent effect was the increase in plasma glucagon. Concurrent administration of mannitol with IFN-alpha caused no changes in the parameters studied compared to that induced by treatment with IFN-alpha alone.

Prediction and design of efficient exciplex emitters for high-efficiency, thermally activated delayed-fluorescence organic light-emitting diodes.

PubMed

Liu, Xiao-Ke; Chen, Zhan; Zheng, Cai-Jun; Liu, Chuan-Lin; Lee, Chun-Sing; Li, Fan; Ou, Xue-Mei; Zhang, Xiao-Hong

2015-04-08

High-efficiency, thermally activated delayed-fluorescence organic light-emitting diodes based on exciplex emitters are demonstrated. The best device, based on a TAPC:DPTPCz emitter, shows a high external quantum efficiency of 15.4%. Strategies for predicting and designing efficient exciplex emitters are also provided. This approach allow prediction and design of efficient exciplex emitters for achieving high-efficiency organic light-emitting diodes, for future use in displays and lighting applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Thermionic gas switch

DOEpatents

Hatch, George L.; Brummond, William A.; Barrus, Donald M.

1986-01-01

A temperature responsive thermionic gas switch having folded electron emitting surfaces. An ionizable gas is located between the emitter and an interior surface of a collector, coaxial with the emitter. In response to the temperature exceeding a predetermined level, sufficient electrons are derived from the emitter to cause the gas in the gap between the emitter and collector to become ionized, whereby a very large increase in current in the gap occurs. Due to the folded emitter surface area of the switch, increasing the "on/off" current ratio and adjusting the "on" current capacity is accomplished.

Minimum emittance in TBA and MBA lattices

NASA Astrophysics Data System (ADS)

Xu, Gang; Peng, Yue-Mei

2015-03-01

For reaching a small emittance in a modern light source, triple bend achromats (TBA), theoretical minimum emittance (TME) and even multiple bend achromats (MBA) have been considered. This paper derived the necessary condition for achieving minimum emittance in TBA and MBA theoretically, where the bending angle of inner dipoles has a factor of 31/3 bigger than that of the outer dipoles. Here, we also calculated the conditions attaining the minimum emittance of TBA related to phase advance in some special cases with a pure mathematics method. These results may give some directions on lattice design.

Simulated Performance of the Wisconsin Superconducting Electron Gun

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

R.A. Bosch, K.J. Kleman, R.A. Legg

2012-07-01

The Wisconsin superconducting electron gun is modeled with multiparticle tracking simulations using the ASTRA and GPT codes. To specify the construction of the emittance-compensation solenoid, we studied the dependence of the output bunch's emittance upon the solenoid's strength and field errors. We also evaluated the dependence of the output bunch's emittance upon the bunch's initial emittance and the size of the laser spot on the photocathode. The results suggest that a 200-pC bunch with an emittance of about one mm-mrad can be produced for a free-electron laser.

Solar absorptance and thermal emittance of some common spacecraft thermal-control coatings

NASA Technical Reports Server (NTRS)

Henninger, J. H.

1984-01-01

Solar absorptance and thermal emittance of spacecraft materials are critical parameters in determining spacecraft temperature control. Because thickness, surface preparation, coatings formulation, manufacturing techniques, etc. affect these parameters, it is usually necessary to measure the absorptance and emittance of materials before they are used. Absorptance and emittance data for many common types of thermal control coatings, are together with some sample spectral data curves of absorptance. In some cases for which ultraviolet and particle radiation data are available, the degraded absorptance and emittance values are also listed.

High-Performance Field Emission from a Carbonized Cork.

PubMed

Lee, Jeong Seok; Lee, Hak Jun; Yoo, Jae Man; Kim, Taewoo; Kim, Yong Hyup

2017-12-20

To broaden the range of application of electron beams, low-power field emitters are needed that are miniature and light. Here, we introduce carbonized cork as a material for field emitters. The light natural cork becomes a graphitic honeycomb upon carbonization, with the honeycomb cell walls 100-200 nm thick and the aspect ratio larger than 100, providing an ideal structure for the field electron emission. Compared to nanocarbon field emitters, the cork emitter produces a high current density and long-term stability with a low turn-on field. The nature of the cork material makes it quite simple to fabricate the emitter. Furthermore, any desired shape of the emitter tailored for the final application can easily be prepared for point, line, or planar emission.

Membrane-Based Emitter for Coupling Microfluidics with Ultrasensitive Nanoelectrospray Ionization-Mass Spectrometry

PubMed Central

Sun, Xuefei; Kelly, Ryan T.; Tang, Keqi; Smith, Richard D.

2011-01-01

An integrated poly(dimethylsiloxane) (PDMS) membrane-based microfluidic emitter for high performance nanoelectrospray ionization-mass spectrometry (nanoESI-MS) has been fabricated and evaluated. The ~100-μm-thick emitter was created by cutting a PDMS membrane that protrudes beyond the bulk substrate. The reduced surface area at the emitter enhances the electric field and reduces wetting of the surface by the electrospray solvent. As such, the emitter enables highly stable electrosprays at flow rates as low as 10 nL/min, and is compatible with electrospray solvents containing a large organic component (e.g., 90% methanol). This approach enables facile emitter construction, and provides excellent stability, reproducibility and sensitivity, as well as compatibility with multilayer soft lithography. PMID:21657269

Design and testing a high fuel volume fraction, externally finned, thermionic emitter.

NASA Technical Reports Server (NTRS)

Peelgren, M. L.; Ernst, D. M.

1971-01-01

A prototypical, high fuel volume fraction, thermionic emitter body was designed and tested. The emitter body is all tungsten, with a 1.40-cm ID, a 3.23-cm OD, and eight full-length axial fins. The emitter thickness is 0.15 cm while the fins and outer clad are 0.075 cm thick. Different methods of fabrication were used in making the test samples. Stress analysis was performed with a three-dimensional elastic code. Thermal testing of the samples, duplicating calculated radial temperature gradients, heatup and cooldown rates, and emitter body temperatures in operation, was performed with no structural failures noted (six heatup and cooldown cycles per sample). Further emitter analysis and testing is planned.

Rare-Earth Oxide (Yb2O3) Selective Emitter Fabrication and Evaluation

NASA Technical Reports Server (NTRS)

Jennette, Bryan; Gregory, Don A.; Herren, Kenneth; Tucker, Dennis; Smith, W. Scott (Technical Monitor)

2001-01-01

This investigation involved the fabrication and evaluation of rare-earth oxide selective emitters. The first goal of this study was to successfully fabricate the selective emitter samples using paper and ceramic materials processing techniques. The resulting microstructure was also analyzed using a Scanning Electron Microscope. All selective emitter samples fabricated for this study were made with ytterbium oxide (Yb2O3). The second goal of this study involved the measurement of the spectral emission and the radiated power of all the selective emitter samples. The final goal of this study involved the direct comparison of the radiated power emitted by the selective emitter samples to that of a standard blackbody at the same temperature and within the same wavelength range.

Solid-state current transformer

NASA Technical Reports Server (NTRS)

Farnsworth, D. L. (Inventor)

1976-01-01

A signal transformation network which is uniquely characterized to exhibit a very low input impedance while maintaining a linear transfer characteristic when driven from a voltage source and when quiescently biased in the low microampere current range is described. In its simplest form, it consists of a tightly coupled two transistor network in which a common emitter input stage is interconnected directly with an emitter follower stage to provide virtually 100 percent negative feedback to the base input of the common emitter stage. Bias to the network is supplied via the common tie point of the common emitter stage collector terminal and the emitter follower base stage terminal by a regulated constant current source, and the output of the circuit is taken from the collector of the emitter follower stage.

Emittance of positron beams produced in intense laser plasma interaction

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

Chen Hui; Hazi, A.; Link, A.

2013-01-15

The first measurement of the emittance of intense laser-produced positron beams has been made. The emittance values were derived through measurements of positron beam divergence and source size for different peak positron energies under various laser conditions. For one of these laser conditions, we used a one dimensional pepper-pot technique to refine the emittance value. The laser-produced positrons have a geometric emittance between 100 and 500 mm{center_dot}mrad, comparable to the positron sources used at existing accelerators. With 10{sup 10}-10{sup 12} positrons per bunch, this low emittance beam, which is quasi-monoenergetic in the energy range of 5-20 MeV, may be usefulmore » as an alternative positron source for future accelerators.« less

Targeted Therapy for Melanoma

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

Quinn, Thomas; Moore, Herbert

The research project, entitled ”Targeted Therapy for Melanoma,” was focused on investigating the use of kidney protection measures to lower the non-specific kidney uptake of the radiolabeled Pb-DOTA-ReCCMSH peptide. Previous published work demonstrated that the kidney exhibited the highest non-target tissue uptake of the 212Pb/203Pb radiolabeled melanoma targeting peptide DOTA-ReCCMSH. The radiolabeled alpha-melanocyte stimulating hormone (α-MSH) peptide analog DOTA-Re(Arg 11)CCMSH, which binds the melanocortin-1 receptor over-expressed on melanoma tumor cells, has shown promise as a PRRT agent in pre-clinical studies. High tumor uptake of 212Pb labeled DOTA-Re(Arg 11)CCMSH resulted in tumor reduction or eradication in melanoma therapy studies. Of particularmore » note was the 20-50% cure rate observed when melanoma mice were treated with alpha particle emitter 212Pb. However, as with most PRRT agents, high radiation doses to the kidneys where observed. To optimize tumor treatment efficacy and reduce nephrotoxicity, the tumor to kidney uptake ratio must be improved. Strategies to reduce kidney retention of the radiolabeled peptide, while not effecting tumor uptake and retention, can be broken into several categories including modification of the targeting peptide sequence and reducing proximal tubule reabsorption.« less

The effect of dimethyl sulfoxide on the induction of DNA strand breaks in plasmid DNA and colony formation of PC Cl3 mammalian cells by alpha-, beta-, and Auger electron emitters (223)Ra, (188)Re, and (99m)Tc.

PubMed

Runge, Roswitha; Oehme, Liane; Kotzerke, Jörg; Freudenberg, Robert

2016-12-01

DNA damage occurs as a consequence of both direct and indirect effects of ionizing radiation. The severity of DNA damage depends on the physical characteristics of the radiation quality, e.g., the linear energy transfer (LET). There are still contrary findings regarding direct or indirect interactions of high-LET emitters with DNA. Our aim is to determine DNA damage and the effect on cellular survival induced by (223)Ra compared to (188)Re and (99m)Tc modulated by the radical scavenger dimethyl sulfoxide (DMSO). Radioactive solutions of (223)Ra, (188)Re, or (99m)Tc were added to either plasmid DNA or to PC Cl3 cells in the absence or presence of DMSO. Following irradiation, single strand breaks (SSB) and double strand breaks (DSB) in plasmid DNA were analyzed by gel electrophoresis. To determine the radiosensitivity of the rat thyroid cell line (PC Cl3), survival curves were performed using the colony formation assay. Exposure to 120 Gy of (223)Ra, (188)Re, or (99m)Tc leads to maximal yields of SSB (80 %) in plasmid DNA. Irradiation with 540 Gy (223)Ra and 500 Gy (188)Re or (99m)Tc induced 40, 28, and 64 % linear plasmid conformations, respectively. DMSO prevented the SSB and DSB in a similar way for all radionuclides. However, with the α-emitter (223)Ra, a low level of DSB could not be prevented by DMSO. Irradiation of PC Cl3 cells with (223)Ra, (188)Re, and (99m)Tc pre-incubated with DMSO revealed enhanced survival fractions (SF) in comparison to treatment without DMSO. Protection factors (PF) were calculated using the fitted survival curves. These factors are 1.23 ± 0.04, 1.20 ± 0.19, and 1.34 ± 0.05 for (223)Ra, (188)Re, and (99m)Tc, respectively. For (223)Ra, as well as for (188)Re and (99m)Tc, dose-dependent radiation effects were found applicable for plasmid DNA and PC Cl3 cells. The radioprotection by DMSO was in the same range for high- and low-LET emitter. Overall, the results indicate the contribution of mainly indirect radiation effects for each of the radionuclides regarding DNA damage and cell survival. In summary, our findings may contribute to fundamental knowledge about the α-particle induced DNA damage.

IL-9 expression by human eosinophils: regulation by IL-1beta and TNF-alpha.

PubMed

Gounni, A S; Nutku, E; Koussih, L; Aris, F; Louahed, J; Levitt, R C; Nicolaides, N C; Hamid, Q

2000-09-01

IL-9 is a pleiotropic cytokine that exhibits biologic activity on cells of diverse hemopoietic lineage. IL-9 stimulates the proliferation of activated T cells, enhances the production of IgE from B cells, and promotes the proliferation and differentiation of mast cells and hematopoietic progenitors. In this study we evaluated the expression of IL-9 messenger (m)RNA and protein by human peripheral blood eosinophils. We also investigated the role of IL-1beta and TNF-alpha in the release of IL-9 from human peripheral blood eosinophils. RT-PCR, in situ hybridization, and immunocytochemistry were used to investigate the presence of IL-9 mRNA and protein in human peripheral blood eosinophils from asthmatic patients and normal control subjects. Furthermore, biologic assay was used to investigate the release of IL-9 protein from IL-1beta- or TNF-alpha-stimulated eosinophils in vitro. RT-PCR analysis showed the presence of IL-9 mRNA in human peripheral blood eosinophil RNA preparations from subjects with atopic asthma, as well as in the eosinophil-differentiated HL-60 cell line. By using in situ hybridization, a significant difference (P <.01) in IL-9 mRNA expression was detected in human peripheral blood eosinophils freshly isolated from asthmatic subjects compared with those isolated from normal control subjects. Furthermore, the percentage of IL-9 immunoreactive eosinophils from asthmatic patients was increased compared with that found in normal control subjects (P <.01). We also demonstrate that cultured human peripheral blood eosinophils from asthmatic subjects synthesize and release IL-9 protein, which is upregulated on stimulation with TNF-alpha and IL-1beta. Human eosinophils express biologically active IL-9, which suggests that these cells may influence the recruitment and activation of effector cells linked to the pathogenesis of allergic disease. These observations provide further evidence for the role of eosinophils in regulating airway immune responses.

Evidence of a novel aggrecan-degrading activity in cartilage: Studies of mice deficient in both ADAMTS-4 and ADAMTS-5.

PubMed

Rogerson, Fraser M; Stanton, Heather; East, Charlotte J; Golub, Suzanne B; Tutolo, Leonie; Farmer, Pamela J; Fosang, Amanda J

2008-06-01

To characterize aggrecan catabolism and the overall phenotype in mice deficient in both ADAMTS-4 and ADAMTS-5 (TS-4/TS-5 Delta-cat) activity. Femoral head cartilage from the joints of TS-4/TS-5 Delta-cat mice and wild-type mice were cultured in vitro, and aggrecan catabolism was stimulated with either interleukin-1alpha (IL-1alpha) or retinoic acid. Total aggrecan release was measured, and aggrecanase activity was examined by Western blotting using neoepitope antibodies for detecting cleavage at EGE 373-374 ALG, SELE 1279-1280 GRG, FREEE 1467-1468 GLG, and AQE 1572-1573 AGEG. Aggrecan catabolism in vivo was examined by Western blotting of cartilage that had been extracted immediately ex vivo. TS-4/TS-5 Delta-cat mice were viable, fertile, and phenotypically normal. TS-4/TS-5 Delta-cat cartilage explants did not release aggrecan in response to IL-1alpha, and there was no detectable increase in aggrecanase neoepitopes. TS-4/TS-5 Delta-cat cartilage explants released aggrecan in response to retinoic acid. There was no retinoic acid-stimulated cleavage at either EGE 373-374 ALG or AQE 1572-1573 AGEG. There was a low level of cleavage at SELE 1279-1280 GRG and major cleavage at FREEE 1467-1468 GLG. Ex vivo, cleavage at FREEE 1467-1468 GLG was substantially reduced, but still present, in TS-4/TS-5 Delta-cat mouse cartilage compared with wild-type mouse cartilage. An aggrecanase other than ADAMTS-4 and ADAMTS-5 is expressed in mouse cartilage and is up-regulated by retinoic acid but not IL-1alpha. The novel aggrecanase appears to have different substrate specificity from either ADAMTS-4 or ADAMTS-5, cleaving E-G bonds but not E-A bonds. Neither ADAMTS-4 nor ADAMTS-5 is required for normal skeletal development or aggrecan turnover in cartilage.

Proteinase-activated receptor-2 stimulates prostaglandin production in keratinocytes: analysis of prostaglandin receptors on human melanocytes and effects of PGE2 and PGF2alpha on melanocyte dendricity.

PubMed

Scott, Glynis; Leopardi, Sonya; Printup, Stacey; Malhi, Namrita; Seiberg, Miri; Lapoint, Randi

2004-05-01

Prostaglandins (PG) are key mediators of diverse functions in the skin and several reports suggest that PG mediate post-inflammatory pigmentary changes through modulation of melanocyte dendricity and melanin synthesis. The proteinase-activated receptor 2 (PAR-2) is important for skin pigmentation because activation of keratinocyte PAR-2 stimulates uptake of melanosomes through phagocytosis in a Rho-dependent manner. In this report, we show that activation of keratinocyte PAR-2 stimulates release of PGE(2) and PGF(2alpha) and that PGE(2) and PGF(2alpha) act as paracrine factors that stimulate melanocyte dendricity. We characterized the expression of the EP and FP receptors in human melanocytes and show that human melanocytes express EP1 and EP3, and the FP receptor, but not EP2 and EP4. Treatment of melanocytes with EP1 and EP3 receptor agonists resulted in increased melanocyte dendricity, indicating that both EP1 and EP3 receptor signaling contribute to PGE(2)-mediated melanocyte dendricity. Certain EP3 receptor subtypes have been shown to increase adenosine 3',5'-cyclic monophosphate (cAMP) through coupling to Gs, whereas EP1 is known to couple to Gq to activate phospholipase C with elevation in Ca(2+). The cAMP/protein kinase A system is known to modulate melanocyte dendrite formation through modulation of Rac and Rho activity. Neither PGF(2alpha) or PGE(2) elevated cAMP in human melanocytes showing that dendricity observed in response to PGE(2) and PGF(2alpha) is cAMP-independent. Our data suggest that PAR-2 mediates cutaneous pigmentation both through increased uptake of melanosomes by keratinocytes, as well as by release of PGE(2) and PGF(2alpha) that stimulate melanocyte dendricity through EP1, EP3, and FP receptors.

Characteristics of alpha-glycerophosphate-evoked H2O2 generation in brain mitochondria.

PubMed

Tretter, Laszlo; Takacs, Katalin; Hegedus, Vera; Adam-Vizi, Vera

2007-02-01

Characteristics of reactive oxygen species (ROS) production in isolated guinea-pig brain mitochondria respiring on alpha-glycerophosphate (alpha-GP) were investigated and compared with those supported by succinate. Mitochondria established a membrane potential (DeltaPsi(m)) and released H(2)O(2) in parallel with an increase in NAD(P)H fluorescence in the presence of alpha-GP (5-40 mm). H(2)O(2) formation and the increase in NAD(P)H level were inhibited by rotenone, ADP or FCCP, respectively, being consistent with a reverse electron transfer (RET). The residual H(2)O(2) formation in the presence of FCCP was stimulated by myxothiazol in mitochondria supported by alpha-GP, but not by succinate. ROS under these conditions are most likely to be derived from alpha-GP-dehydrogenase. In addition, huge ROS formation could be provoked by antimycin in alpha-GP-supported mitochondria, which was prevented by myxothiazol, pointing to the generation of ROS at the quinol-oxidizing center (Q(o)) site of complex III. FCCP further stimulated the production of ROS to the highest rate that we observed in this study. We suggest that the metabolism of alpha-GP leads to ROS generation primarily by complex I in RET, and in addition a significant ROS formation could be ascribed to alpha-GP-dehydrogenase in mammalian brain mitochondria. ROS generation by alpha-GP at complex III is evident only when this complex is inhibited by antimycin.

Luminous phenomena and electromagnetic VHF wave emission originated from earthquake-related radon exhalation

NASA Astrophysics Data System (ADS)

Seki, A.; Tobo, I.; Omori, Y.; Muto, J.; Nagahama, H.

2013-12-01

Anomalous luminous phenomena and electromagnetic wave emission before or during earthquakes have been reported (e.g., the 1965 Matsushiro earthquake swarm). However, their mechanism is still unsolved, in spite of many models for these phenomena. Here, we propose a new model about luminous phenomena and electromagnetic wave emission during earthquake by focusing on atmospheric radon (Rn-222) and its daughter nuclides (Po-218 and Po-214). Rn-222, Po-218 and Po-214 are alpha emitters, and these alpha particles ionize atmospheric molecules. A light emission phenomenon, called 'the air luminescence', is caused by de-excitation of the ionized molecules of atmospheric nitrogen due to electron impact ionization from alpha particles. The de-excitation is from the second positive system of neutral nitrogen molecules and the first negative system of nitrogen molecule ion. Wavelengths of lights by these transitions include the visible light wavelength. So based on this mechanism, we proposed a new luminous phenomenon model before or during earthquake: 1. The concentration of atmospheric radon and its daughter nuclides increase anomalously before or during earthquakes, 2. Nitrogen molecules and their ions are excited by alpha particles emitted from Rn-222, Po-218 and Po-214, and air luminescence is generated by their de-excitation. Similarly, electromagnetic VHF wave emission can be explained by ionizing effect of radon and its daughter nuclides. Boyarchuk et al. (2005) proposed a model that electromagnetic VHF wave emission is originated when excited state of neutral clusters changes. Radon gas ionizes atmosphere and forms positively and negatively charged heavy particles. The process of ion hydration in ordinary air can be determined by the formation of complex chemically active structures of the various types of ion radicals. As a result of the association of such hydration radical ions, a neutral cluster, which is dipole quasi-molecules, is formed. A neutral cluster's rotation-rotation transition causes electromagnetic VHF wave emission. We also discuss a possibility of electromagnetic VHF wave emission from excitation of polyatomic molecules by alpha particles from Rn-222 and its daughter nuclides, similar to air luminescence by excitation of nitrogen molecule in the viewpoint of electromagnetic radiation in quantum theory.

Highly reliable field electron emitters produced from reproducible damage-free carbon nanotube composite pastes with optimal inorganic fillers.

PubMed

Kim, Jae-Woo; Jeong, Jin-Woo; Kang, Jun-Tae; Choi, Sungyoul; Ahn, Seungjoon; Song, Yoon-Ho

2014-02-14

Highly reliable field electron emitters were developed using a formulation for reproducible damage-free carbon nanotube (CNT) composite pastes with optimal inorganic fillers and a ball-milling method. We carefully controlled the ball-milling sequence and time to avoid any damage to the CNTs, which incorporated fillers that were fully dispersed as paste constituents. The field electron emitters fabricated by printing the CNT pastes were found to exhibit almost perfect adhesion of the CNT emitters to the cathode, along with good uniformity and reproducibility. A high field enhancement factor of around 10,000 was achieved from the CNT field emitters developed. By selecting nano-sized metal alloys and oxides and using the same formulation sequence, we also developed reliable field emitters that could survive high-temperature post processing. These field emitters had high durability to post vacuum annealing at 950 °C, guaranteeing survival of the brazing process used in the sealing of field emission x-ray tubes. We evaluated the field emitters in a triode configuration in the harsh environment of a tiny vacuum-sealed vessel and observed very reliable operation for 30 h at a high current density of 350 mA cm(-2). The CNT pastes and related field emitters that were developed could be usefully applied in reliable field emission devices.

Highly reliable field electron emitters produced from reproducible damage-free carbon nanotube composite pastes with optimal inorganic fillers

NASA Astrophysics Data System (ADS)

Kim, Jae-Woo; Jeong, Jin-Woo; Kang, Jun-Tae; Choi, Sungyoul; Ahn, Seungjoon; Song, Yoon-Ho

2014-02-01

Highly reliable field electron emitters were developed using a formulation for reproducible damage-free carbon nanotube (CNT) composite pastes with optimal inorganic fillers and a ball-milling method. We carefully controlled the ball-milling sequence and time to avoid any damage to the CNTs, which incorporated fillers that were fully dispersed as paste constituents. The field electron emitters fabricated by printing the CNT pastes were found to exhibit almost perfect adhesion of the CNT emitters to the cathode, along with good uniformity and reproducibility. A high field enhancement factor of around 10 000 was achieved from the CNT field emitters developed. By selecting nano-sized metal alloys and oxides and using the same formulation sequence, we also developed reliable field emitters that could survive high-temperature post processing. These field emitters had high durability to post vacuum annealing at 950 °C, guaranteeing survival of the brazing process used in the sealing of field emission x-ray tubes. We evaluated the field emitters in a triode configuration in the harsh environment of a tiny vacuum-sealed vessel and observed very reliable operation for 30 h at a high current density of 350 mA cm-2. The CNT pastes and related field emitters that were developed could be usefully applied in reliable field emission devices.

Resolution of G(s)alpha and G(q)alpha/G(11)alpha proteins in membrane domains by two-dimensional electrophoresis: the effect of long-term agonist stimulation.

PubMed

Matousek, P; Novotný, J; Svoboda, P

2004-01-01

Low-density membrane-domain fractions were prepared from S49 lymphoma cells and clone e2m11 of HEK293 cells expressing a large number of thyrotropin-releasing hormone receptor (TRH-R) and G(11)alpha by flotation on sucrose density gradients. The intact cell structure was broken by detergent-extraction, alkaline-treatment or drastic homogenization. Three types of low-density membranes were resolved by two-dimensional electrophoresis and analyzed for G(s)alpha (S49) or G(q)alpha/G11) (e2m11) content. Four individual immunoblot signals of Gsalpha protein were identified in S49 lymphoma cells indicating complete resolution of the long G(s)alpha L+/-ser and short G(s)alpha S+/-ser variants of G(s)alpha. All these were diminished by prolonged agonist (isoprenaline) stimulation. In e2m11-HEK cells, five different immunoblot signals were detected indicating post-translational modification of G proteins of G(q)alpha/G(11)alpha family. The two major spots corresponding to exogenously (over)expressed G(11)alpha and endogenous G(q)alpha were reduced; the minor spots diminished by hormonal stimulation. Parallel analysis by silver staining of the total protein content indicated that no major changes in protein composition occurred under these conditions. Our data thus indicate that agonist-stimulation of target cells results in down-regulation of all different members of G(s) and G(q)/G(11) families. This agonist-specific effect may be demonstrated in crude membrane as well as domain/raft preparations and it is not accompanied by changes in overall protein composition.

Using antennas separated in flight direction to avoid effect of emitter clock drift in geolocation

DOEpatents

Ormesher, Richard C.; Bickel, Douglas L

2012-10-23

The location of a land-based radio frequency (RF) emitter is determined from an airborne platform. RF signaling is received from the RF emitter via first and second antennas. In response to the received RF signaling, signal samples for both antennas are produced and processed to determine the location of the RF emitter.

Efficient triplet harvesting of hybrid white organic light-emitting diodes using thermally activated delayed fluorescence green emitter

NASA Astrophysics Data System (ADS)

Lee, Song Eun; Lee, Ho Won; Baek, Hyun Jung; Yun, Tae Jun; Yun, Geum Jae; Kim, Woo Young; Kim, Young Kwan

2016-10-01

Hybrid white organic light-emitting diodes (WOLEDs) were fabricated by applying triplet harvesting (TH) using a green thermally activated delayed fluorescence (TADF) emitter. The triplet exciton of the green TADF emitter can be upconverted to its singlet state. The TH involved energy transfer of triplet exciton from a blue fluorescent emitter to a green TADF and red phosphorescent emitters, where they can decay radiatively. In addition, the triplet exciton of the green TADF emitter was energy transferred to its singlet state for a reverse intersystem crossing by green emission. Enhanced hybrid WOLEDs were demonstrated using an efficient green TADF emitter combined with red phosphorescent and blue fluorescent emitters. Hybrid WOLEDs were fabricated with various hole-electron recombination zones as changing blue emitting layer thicknesses. Among these, hybrid WOLEDs showed a maximum external quantum efficiency of 11.23%, luminous efficiency of 29.20 cd/A, and a power efficiency of 26.21 lm/W. Moreover, the WOLED exhibited electroluminescence spectra with Commission International de L'Éclairage chromaticity of (0.38, 0.36) at 1000 cd/m2 and a color rendering index of 82 at a practical brightness of 20,000 cd/m2.